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  • 1
    Online Resource
    Online Resource
    Berlin : Springer Berlin | Springer
    Part of "Beiträge zum ausländischen öffentlichen Recht und Völkerrech ..."
    Keywords: Europäischer Gerichtshof für Menschenrechte ; Rechtsprechung ; Beweisführung ; Hochschulschrift ; Europäischer Gerichtshof für Menschenrechte ; Rechtsprechung ; Beweisführung
    Type of Medium: Online Resource
    Edition: 1. Auflage 2019
    ISBN: 9783662602645
    Series Statement: Beiträge zum ausländischen öffentlichen Recht und Völkerrecht Band 288
    Language: German , English
    Dissertation note: Dissertation Bucerius Law School 2019
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  • 2
    Online Resource
    Online Resource
    Wiesbaden : Springer Fachmedien Wiesbaden GmbH | Springer
    Keywords: Immaterialgut ; Rechtsverletzung ; Wettbewerbsverstoß ; Verkehrssicherungspflicht ; Dritthaftung ; Beseitigungsanspruch ; Unterlassungsanspruch ; LA ; Gefahrengeneigte Geschäftsmodelle ; Intermediär ; Störerhaftung ; Teilnehmerhaftung ; Verkehrspflichten aus Ingerenz ; LA ; Hochschulschrift ; Immaterialgut ; Rechtsverletzung ; Wettbewerbsverstoß ; Verkehrssicherungspflicht ; Dritthaftung ; Beseitigungsanspruch ; Unterlassungsanspruch
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (XIII, 255 Seiten)
    ISBN: 9783658251062
    Series Statement: Juridicum - Schriften zum Unternehmens- und Wirtschaftsrecht
    Language: German
    Dissertation note: Dissertation Universität Konstanz 2018
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  • 3
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    Springer
    Publication Date: 2018-03-05
    Print ISSN: 0949-1775
    Electronic ISSN: 1432-0517
    Topics: Chemistry and Pharmacology
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  • 4
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    Springer
    Publication Date: 2018-03-05
    Description: In the penultimate paragraph of the original publication, a confidence interval of 93 mg/kg to 971 mg/kg was reported. These values should be 114.5 mg/kg to 786.2 mg/kg.
    Print ISSN: 0949-1775
    Electronic ISSN: 1432-0517
    Topics: Chemistry and Pharmacology
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  • 5
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    Springer
    Publication Date: 2018-03-05
    Print ISSN: 0949-1775
    Electronic ISSN: 1432-0517
    Topics: Chemistry and Pharmacology
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  • 6
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    Springer
    Publication Date: 2018-03-05
    Description: An uncertainty comparison method is proposed to assess the homogeneity of reference materials. The method compares “standard uncertainty associated with between-unit variability” ( u bb ) with “target standard uncertainty” ( u trg ) or “measurement uncertainty” ( u meas ) to solve the problems in assessing homogeneity of reference materials. Methods for the calculation of u bb , u trg and u meas as well as criterion for the quantitative judgment of sample homogeneity are introduced. When u bb  ≤ 0.3 u trg , it shows the sample is considered to be homogeneous; when 0.3 u trg  〈  u bb  ≤ 0.7 u trg , the sample is considered to be sufficiently homogeneous for the intended use; and when u bb  〉 0.7 u trg , the sample is considered to be inhomogeneous. The uncertainty comparison method is compared with the F test method and shown to be more objective for the assessment of the homogeneity of certified reference materials for the chemical testing of toys.
    Print ISSN: 0949-1775
    Electronic ISSN: 1432-0517
    Topics: Chemistry and Pharmacology
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  • 7
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    Springer
    Publication Date: 2018-03-05
    Print ISSN: 0949-1775
    Electronic ISSN: 1432-0517
    Topics: Chemistry and Pharmacology
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  • 8
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    Springer
    Publication Date: 2018-03-05
    Description: Based on the Brazilian test results of 23 kinds of transversely isotropic rocks, five trends are obtained for the variation of normalized failure strength (NFS) as a function of the weak plane-loading angles. For each angle, three kinds of fracture patterns are obtained. Furthermore, a new numerical approach based on the particle discrete element method is put forward to systematically investigate the influence of the micro-structure of rock matrix and strength of weak plane on NFS and fracture patterns. The results reveal that the trend of NFS and fracture patterns are slightly influenced by coordination number of rock particles and tensile strength of weak plane, but greatly influenced by percentage of pre-existing cracks and shear strength of weak plane. Micro-parameters of the numerical approach are calibrated to reproduce behaviours of transversely isotropic rocks with different trends, and the simulation results are well matched with experimental results in terms of NFS and fracture patterns. Finally, the numerical approach is applied to study the failure process of layered surrounding rock after tunnel excavation. The simulation results also agree well with observation results of engineering projects.
    Print ISSN: 1861-1125
    Electronic ISSN: 1861-1133
    Topics: Geosciences
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  • 9
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    Publication Date: 2018-03-05
    Description: The reduction in volume for unsaturated soils wetted at constant total stress is indicated as capillary collapse. Several studies conducted on standard laboratory specimens (macro-scale) outlined the role of initial void ratio, confining pressure and matric suction on collapse onset. Conversely, few observations were made at grain scale, although an important influence of soil structure has been supposed since years. This paper investigated the collapse of coarse and fine sands derived from a pyroclastic soil of Southern Italy. The X-ray computed tomography was used to identify the mechanisms acting at grain scale and to measure the local variations of soil structure. The experimental procedure consisted in preparing remoulded unsaturated specimens and reducing the matric suction until the collapse occurred under self-weight. At different stages of the process, the sample was imaged by X-ray tomography. The experimental results provided original insight into: (1) transformation of soil structure during the wetting tests; (2) variation of porosity, water content and degree of saturation for the whole specimen; and (3) local variations of those variables in several representative sub-volumes. It is worth noting that collapse of coarse sand specimen occurred before saturation. This was also emphasized by the presence of macro-voids at collapse.
    Print ISSN: 1861-1125
    Electronic ISSN: 1861-1133
    Topics: Geosciences
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  • 10
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    Springer
    Publication Date: 2018-03-05
    Description: Numerical modelling of a field soil desiccation test is performed using a hybrid continuum-discrete element method with a mix-mode cohesive fracture model and Voronoi tessellation grain assemblages. The fracture model considers material strength and contact stiffness degradation in both normal and tangential directions of an interface. It is found that the model can reasonably reproduce the special features of the field soil desiccation, such as curling and sub-horizontal crack. In addition, three significant factors controlling field desiccation cracking, fracture energy, grain heterogeneity and grain size are identified.
    Print ISSN: 1861-1125
    Electronic ISSN: 1861-1133
    Topics: Geosciences
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  • 11
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    Springer
    In: 4OR
    Publication Date: 2018-03-05
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 12
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    In: 4OR
    Publication Date: 2018-03-05
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 13
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    Springer
    In: 4OR
    Publication Date: 2018-03-05
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 14
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    In: 4OR
    Publication Date: 2018-03-05
    Description: This is the traditional triennial note used by the editors to give the readers of 4OR information on the state of the journal and its future. In the 3 years that have passed since the last editorial note (Liberti et al. in Q J Oper 13:1–13, 2015 ), three volumes (each containing four issues) of the journal have been published: vol. 13 (2015), vol. 14 (2016), and vol. 15 (2017).
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 15
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    In: 4OR
    Publication Date: 2018-03-05
    Description: In this paper, we study a vector scheduling problem with rejection on a single machine, in which each job is characterized by a d -dimension vector and a penalty, in the sense that, jobs can be either rejected by paying a certain penalty or assigned to the machine. The objective is to minimize the sum of the maximum load over all dimensions of the total vector of all accepted jobs, and the total penalty of rejected jobs. We prove that the problem is NP-hard and design two approximation algorithms running in polynomial time. When d is a fixed constant, we present a fully polynomial time approximation scheme.
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 16
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    In: 4OR
    Publication Date: 2018-03-05
    Description: In this paper we analyze an inter-temporal optimization problem of a representative firm that invests in horizontal and vertical innovations and that faces a constraint with respect to total R&D spending. We find that there can exist two different steady-states of the economy when the amount of research spending falls short of an endogenously determined threshold: one with higher productivities and less new technologies being developed, and the other with more technologies being created and lower productivities. But, for a higher amount of R&D spending the steady-state becomes unique and the firm produces the whole spectrum of available technologies. Thus, a lock-in effect may arise that, however, can be overcome by raising R&D spending sufficiently.
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 17
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    Springer
    In: 4OR
    Publication Date: 2018-03-05
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 18
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    In: 4OR
    Publication Date: 2018-03-05
    Description: In this study, we deal with the problem of short-term transportation outsourcing for transshipment centers. The carrier needs to determine the numbers of outsourced and self-run trips for the different types of transportation tasks. Stochastic demands which are likely to occur in actual operation are considered. Different trip numbers need to be determined in sequence, so a two-stage stochastic programming technique is applied to formulate the problem. Two models are developed based upon practical considerations to help determine the optimal transportation outsourcing plan. A case study regarding the operations of a logistics carrier in Taiwan is performed. Several tests are also performed considering the number of demand scenarios, optimality gaps, variations in demands, outsourcing cost variations, and problem dimensions in order to better understand the performance of the two models.
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 19
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    In: 4OR
    Publication Date: 2018-03-05
    Description: In the context of recreational routing, the problem of finding a route which starts and ends in the same location (while achieving a length between specified upper and lower boundaries) is a common task, especially for tourists or cyclists who want to exercise. The topic of finding a tour between a specified starting and ending location while minimizing one or multiple criteria is well covered in literature. In contrast to this, the route planning task in which a pleasant tour with length between a maximum and a minimum boundary needs to be found is relatively underexplored. In this paper, we provide a formal definition of this problem, taking into account the existing literature on which route attributes influence cyclists in their route choice. We show that the resulting problem is NP-hard and devise a branch-and-bound algorithm that is able to provide a bound on the quality of the best solution in pseudo-polynomial time. Furthermore, we also create an efficient heuristic to tackle the problem and we compare the quality of the solutions that are generated by the heuristic with the bounds provided by the branch-and-bound algorithm. Also, we thoroughly discuss the complexity and running time of the heuristic.
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 20
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    In: 4OR
    Publication Date: 2018-03-05
    Description: Interior point methods usually rely on iterative methods to solve the linear systems of large scale problems. The paper proposes a hybrid strategy using groups for the preconditioning of these iterative methods. The objective is to solve large scale linear programming problems more efficiently by a faster and robust computation of the preconditioner. In these problems, the coefficient matrix of the linear system becomes ill conditioned during the interior point iterations, causing numerical difficulties to find a solution, mainly with iterative methods. Therefore, the use of preconditioners is a mandatory requirement to achieve successful results. The paper proposes the use of a new columns ordering for the splitting preconditioner computation, exploring the sparsity of the original matrix and the concepts of groups. This new preconditioner is designed specially for the final interior point iterations; a hybrid approach with the controlled Cholesky factorization preconditioner is adopted. Case studies show that the proposed methodology reduces the computational times with the same quality of solutions when compared to previous reference approaches. Furthermore, the benefits are obtained while preserving the sparse structure of the systems. These results highlight the suitability of the proposed approach for large scale problems.
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 21
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    In: 4OR
    Publication Date: 2018-03-05
    Description: Fritz John and Karush–Kuhn–Tucker necessary conditions for local LU-optimal solutions of the constrained interval-valued optimization problems involving inequality, equality and set constraints in Banach spaces in terms of convexificators are established. Under suitable assumptions on the generalized convexity of objective and constraint functions, sufficient conditions for LU-optimal solutions are given. The dual problems of Mond–Weir and Wolfe types are studied together with weak and strong duality theorems for them.
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 22
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    In: 4OR
    Publication Date: 2018-03-05
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 23
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    In: 4OR
    Publication Date: 2018-03-05
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 24
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    In: 4OR
    Publication Date: 2018-03-05
    Print ISSN: 1619-4500
    Electronic ISSN: 1614-2411
    Topics: Mathematics
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  • 25
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    Publication Date: 2018-03-05
    Description: Advances in multi-material 3D printing technologies have opened a new horizon for design and fabrication of architected multi-materials in multiple length scales from nano-/microscale to meso-/macroscales. In this study, we apply modified couple stress and first-order shear deformation theories for a size-dependent structural analysis of 3D printable functionally graded (FG) doubly-curved panels where their microarchitecture can be engineered to improve their structural performance. This non-classical model incorporates the microstructure-dependent size effects for the structural performance through the introduction of a length scale in the kinematics of deformation. The volume fraction of matrix in the dual-phase (inclusion and matrix) FG size-dependent panels varies continuously through the thickness. The microarchitecture of inclusion and matrix in FG panels is engineered to show its effect on the structural responses. We implement the standard mechanics homogenization technique via finite element simulation to accurately predict the effective mechanical properties of FG materials for different topologies of engineered microarchitecture to show the significance of selecting appropriate micromechanical modeling for analyzing FG structures. Governing equations derived by variational Hamilton’s principle are solved by applying the Galerkin method for different sets of boundary conditions. We investigate the effects of material length scale, material composition, heterogeneous material distribution, particulate topology, length-to-thickness ratio, and panel curvature on the structural performance. It is found that the fundamental frequencies of size-dependent two-phase FG doubly-curved panels with square-shape inclusions are higher than for those with other topologies, which sheds lights on the engineering of the inclusion shape in advanced architected materials to optimize their structural performance.
    Print ISSN: 0001-5970
    Electronic ISSN: 1619-6937
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 26
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    Publication Date: 2018-03-05
    Description: Considering both single and multiple time delays, partial pole assignment for stabilising asymmetric systems is exemplified by friction-induced vibration and aerodynamic flutter. The control strategy is a single-input state feedback including constant time delays in the feedback loop. An unobservability condition is considered to assign some poles while keeping others unchanged. The receptance method is applied to avoid modelling errors from evaluating mass, damping and stiffness matrices by the finite element method. The solution is formulated in linear equations which allow determination of control gains. The stability of the closed-loop system is analysed by evaluating the first few dominant poles and determining a critical time delay. The numerical study shows that the proposed method is capable of making partial pole assignment with time delays. Since many structures and systems with non-conservative forces can be represented by asymmetric systems, this approach is widely applicable for vibration control of engineering structures.
    Print ISSN: 0001-5970
    Electronic ISSN: 1619-6937
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 27
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    Publication Date: 2018-03-05
    Description: In this paper, we present the elastic solutions for the problem of an internal pressurized functionally graded thick-walled tube based on the Voigt method in Xin et al. (Int J Mech Sci 89:344–349, 2014 ); a transversely isotropic functionally graded thick-walled tube subjected to internal pressure is studied. It is assumed that the functionally graded tube is made up of two linear isotropic elastic materials; the matrix is reinforced by fibers with circular cross section all aligned in the circumferential direction. The volume fraction of the reinforced material is identical with our previous work (i.e., Xin et al. in Int J Mech Sci 89:344–349, 2014 ). By using the Mori–Tanaka method, this paper obtains the differential equation of the radial displacement and then the numerical results of the radial displacement and the stresses are deduced. The approximate analytical solutions are also derived which agree well with the numerical results on the basis of the Mori–Tanaka method. Further, both based on the Mori–Tanaka method, the results received by the present model are compared with those by a particle model for solving an isotropic inner-pressurized FGM tube problem. Finally, in the numerical part the influences of the volume fraction and the elastic moduli’s ratio on radial displacement and the stresses are discussed.
    Print ISSN: 0001-5970
    Electronic ISSN: 1619-6937
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 28
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    Publication Date: 2018-03-05
    Description: In this paper, an elastic metamaterial is proposed by integrating a two-dimensionally periodic honeycomb lattice and tetrachiral metamaterial inclusions for low-frequency wave applications. Plane wave propagation in infinite periodic cells is investigated through using Floquet–Bloch principles and the finite element method. Two separate negative pass bands induced by different mechanisms appear in the band structures of wave propagation in the proposed elastic metamaterial. The working mechanisms of those two negative pass bands are revealed though analyzing the eigenmodes of the unit cell and the dynamic effective material properties. Numerical examples validate the proposed model and show that negative refraction of elastic waves in the elastic metamaterial has been obtained. The design concept of this type of elastic may be of use for the design of broadband flat lenses for elastic wave focusing.
    Print ISSN: 0001-5970
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 29
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    Publication Date: 2018-03-05
    Description: This paper presents a smoothed FE-Meshfree (SFE-Meshfree) method for solving solid mechanics problems. The system stiffness matrix is calculated via a strain-smoothing technique with the composite shape function, which is based on the partition of unity-based method, combing the classical isoparametric quadrilateral function and radial-polynomial basis function. The corresponding Gauss integration in the element is replaced by line integration along the edges of the smoothing cells, so no derivatives of the composite shape functions are needed during the field gradient estimation process. Several numerical examples including an automobile mechanical component are employed to examine the presented method. Calculation results indicate that SFE-Meshfree can obtain a high convergence rate and accuracy without introducing additional degrees of freedom to the system. In addition, it is also more tolerant with respect to mesh distortion. The volumetric locking problem is also explored in this paper under a selective smoothing integration scheme.
    Print ISSN: 0001-5970
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 30
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    Publication Date: 2018-03-05
    Description: This paper concerns a new and fast meshfree method for the linear coupled thermoelasticity problem. The resulting algorithm provides an attractive alternative to existing mesh-based and meshfree methods. Compared with mesh-based methods, the proposed technique inherits the advantages of meshfree methods allowing the use of scattered points instead of a predefined mesh. Compared with the existing meshfree methods, the proposed technique is truly meshless, requiring no background mesh for both trial and test spaces and, more importantly, numerical integrations are done over low-degree polynomials rather than complicated shape functions. In fact, this method mimics the known advantages of both meshless and finite element methods, where in the former triangulation is not required for approximation and in the latter the stiffness and mass matrices are set up by integration against simple polynomials. The numerical results of the present work concern the thermal and mechanical shocks in a finite domain considering classical coupled theory of thermoelasticity.
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 31
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    Publication Date: 2018-03-05
    Description: Under consideration is the finite-size scaling of the elastic properties in two-phase random polycrystals with individual grains belonging to any arbitrary crystal class. These polycrystals are generated by Voronoi Tessellations with varying grain sizes and volume fractions. Any given realization of such a microstructure sampled randomly is highly anisotropic and heterogeneous. Using extremum principles in elasticity, we introduce the notion of a ‘Heterogeneous Anisotropy Index \(\left( A^U_H\right) \) ’ and examine its role in the scaling of elastic properties at finite mesoscales ( \(\delta \) ). The relationship between \(A^U_H\) and the Universal Anisotropy Index \(A^U\) by Ranganathan and Ostoja-Starzewski (Phys Rev Lett 101(5):055504, 2008 ) is established for special cases. The index \(A^U_H\) turns out to be a function of 43 variables—21 independent components for each phase and the volume fraction of either phase. The scale-dependent bounds are then obtained by setting up and solving 9250 Dirichlet and Neumann type boundary value problems consistent with the Hill–Mandel homogenization condition. Subsequently, the concept of an elastic scaling function is introduced that takes a power-law form in terms of \(A^U_H\) and ( \(\delta \) ). Finally, a material scaling diagram is constructed by employing the elastic scaling function which captures the convergence to the effective properties for any two-phase elastic microstructure.
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 32
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    Publication Date: 2018-03-05
    Description: According to classical gas dynamic theory, if a steady supersonic parallel flow encounters a sudden change in the wall slope, two very different phenomena may occur. If the flow expands around a sharp corner, the well-known isentropic Prandtl–Meyer fan is observed. Conversely, a shock wave occurs if the flow is compressed: for wedge angles smaller than the detachment value, which depends on the uniform upstream state, an oblique shock originates at the corner; at larger deviation angles, a detached shock is formed. A unified description of these flows is presented here to extend the validity of the common \(\beta \) – \(\vartheta \) (shock angle–deflection angle) diagram for shocked non-isentropic flows into the realm of isentropic expansions. The new graph allows for a straightforward identification of the wave angles for self-similar flow fields around compressive and rarefactive corners. Besides, it clarifies the relation between shock waves and rarefaction fans in the neighbourhood of the \({\vartheta =0}\) axis, where shock waves are weak enough to be fairly well approximated by isentropic compressions. At \({\vartheta =0}\) , indeed, shock and rarefaction curves are demonstrated to be first order continuous. This result is interpreted in view of the bisector rule for oblique shock waves. Exemplary diagrams are reported for both ideal-gas flows, dilute-gas flows and non-ideal flows of dense vapours in the close proximity of the liquid–vapour saturation curve and critical point. The application of the new diagram is illustrated for the textbook case of the supersonic flow past a diamond-shaped airfoil.
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 33
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    Publication Date: 2018-03-05
    Print ISSN: 0001-5970
    Electronic ISSN: 1619-6937
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 34
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    Publication Date: 2018-03-05
    Description: Molecular dynamics simulations with Adaptive Intermolecular Reactive Empirical Bond Order force fields were conducted to determine the transversely isotropic elastic properties of carbon nanotubes (CNTs) containing vacancies. This is achieved by imposing axial extension, twist, in-plane biaxial tension, and in-plane shear to the defective CNTs. The effects of vacancy concentrations, their position, and the diameter of armchair CNTs were taken into consideration. Current results reveal that vacancy defects affect (i) the axial Young’s and shear moduli of smaller-diameter CNTs more than the larger ones and decrease by 8 and 16% for 1 and 2% vacancy concentrations, respectively; (ii) the plane strain bulk and the in-plane shear moduli of the larger-diameter CNTs more profoundly, reduced by 33 and 45% for 1 and 2% vacancy concentrations, respectively; and (iii) the plane strain bulk and in-plane shear moduli among all the elastic coefficients. It is also revealed that the position of vacancies along the length of CNTs is the main influencing factor which governs the change in the properties of CNTs, especially for vacancy concentration of 1%. The current fundamental study highlights the important role played by vacancy defected CNTs in determining their mechanical behaviors as reinforcements in multifunctional nanocomposites.
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 35
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    Publication Date: 2018-03-05
    Description: In this paper, we propose and study a single-phase elastic metamaterial with periodic chiral local resonator, which is composed of cylindrical central core surrounded by evenly distributed ligaments and embedded in the matrix in a square lattice. Based on the analytical and numerical analysis, we prove that the translational resonance of the unit cell can lead to negative effective mass density, and the rotational resonance of it can produce negative effective modulus. They can also work together to generate double-negative effective material properties. The wave attenuation of elastic waves in this elastic metamaterial is also demonstrated, which is owing to the negative effective mass density. In addition, the damping of the base material is also considered in the simulation. We finally examine the existence of negative band, and this leads to the physics of negative refraction, which is induced by simultaneous translational and rotational resonance of the unit cell. Our work can serve as the theoretical foundation for the design of single-phase elastic metamaterials.
    Print ISSN: 0001-5970
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 36
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    Publication Date: 2018-03-05
    Description: The problem of structural design of polymeric and composite viscoelastic materials is currently of great interest. The development of new methods of calculation of the stress–strain state of viscoelastic solids is also a current mathematical problem, because when solving boundary value problems one needs to consider the full history of exposure to loads and temperature on the structure. The article seeks to build an iterative algorithm for calculating the stress–strain state of viscoelastic structures, enabling a complete separation of time and space variables, thereby making it possible to determine the stresses and displacements at any time without regard to the loading history. It presents a modified theoretical basis of the iterative algorithm and provides analytical solutions of variational problems based on which the measure of the rate of convergence of the iterative process is determined. It also presents the conditions for the separation of space and time variables. The formulation of the iterative algorithm, convergence rate estimates, numerical computation results, and comparisons with exact solutions are provided in the tension plate problem example.
    Print ISSN: 0001-5970
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 37
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    Publication Date: 2018-03-05
    Description: This manuscript investigates the thermal stresses and temperatures in a porous plate hydrated with a liquid. The upper surface is taken to be impermeable, traction free and subjected to a thermal shock. The lower surface is laid on a rigid foundation. The effect of the porosity is analyzed through graphs. It is noticed that all functions for the two phases increase with the increasing porosity except for the stress and the displacement. The effect of time is analyzed through graphs. It is observed that the heat and elastic effects propagate with finite speeds. Comparison is made with a problem with the same configuration in the absence of fluid when the medium is not porous. It was found that the existence of the fluid decreases the temperature and the displacement, whereas opposite behavior is observed for the stress.
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 38
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    Publication Date: 2018-03-05
    Description: In this paper, we study buckling of radially FGM circular plates. In a previous study, a fourth-order polynomial expressing the exact solution of a linear elastic problem was used as buckling mode shape. To generalise such investigation, in this contribution the buckling mode is postulated to take the shape of a fifth-order polynomial function of the radial coordinate. The flexural rigidity is consequently sought as a polynomial of suitable order, expressing the functional grading. New solutions in closed form are then obtained by a semi-inverse method. It is found that suitable choices of functional grading may increase the buckling load up to 246% with respect to the homogeneous and uniform cases.
    Print ISSN: 0001-5970
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 39
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    Publication Date: 2018-03-05
    Description: The purpose of this study is to analyze the nonlinear dynamic responses of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) beams exposed to axial supersonic airflow in thermal environments. The dynamic model of the FG-CNTRC beam is developed with regard to the first-order shear deformation theory incorporating the von Kármán geometrical nonlinearity. The thermomechanical properties of the constituents are assumed to be temperature dependent. The third-order piston theory is adopted to estimate the nonlinear aerodynamic pressure induced by the supersonic airflow. Harmonic differential quadrature method is implemented to discretize the equations of motion in the spatial domain. A comprehensive parametric study is performed to expatiate on the effect of the distribution type and volume fraction of CNTs, boundary condition, slenderness ratio, and thermal environments on the aerothermoelastic responses of the FG-CNTRC beam. Simulation results indicate that the presence of the aerodynamic pressure not only increases the critical buckling temperature of the FG-CNTRC beam, but also changes the buckling mode shapes of the beam. Furthermore, the results show that aerothermoelastic characteristics of FG-CNTRC beams may be remarkably improved by the selection of a proper distribution of CNTs. Besides, it is found that FG-CNTRC beams with intermediate CNT volume fraction do not have an intermediate critical buckling temperature.
    Print ISSN: 0001-5970
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 40
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    Publication Date: 2018-03-05
    Description: The sensitivity of tropical cyclone (TC) intensification to the ambient rotation effect under vertical shear is investigated. The results show that the vortices develop more rapidly with intermediate planetary vorticity, which suggests an optimal latitude for the TC development in the presence of vertical shear. This is different from the previous studies in which no mean flow is considered. It is found that the ambient rotation has two main effects. On the one hand, the boundary layer imbalance is largely controlled by the Coriolis parameter. For TCs at lower latitudes, due to the weaker inertial instability, the boundary inflow is promptly established, which results in a stronger moisture convergence and thus greater diabatic heating in the inner core region. On the other hand, the Coriolis parameter modulates the vertical realignment of the vortex with a higher Coriolis parameter, favoring a quicker vertical realignment and thus a greater potential for TC development. The combination of these two effects results in an optimal latitude for TC intensification in the presence of a vertical shear investigated.
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    Topics: Geosciences
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  • 41
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    Publication Date: 2018-03-05
    Description: By using idealized numerical simulations, the impact of tropical cyclone size on secondary eyewall formation (SEF) is examined. Both unbalanced boundary layer and balanced processes are examined to reveal the underlying mechanism. The results show that a tropical cyclone (TC) with a larger initial size favors a quicker SEF and a larger outer eyewall. For a TC with a larger initial size, it will lead to a stronger surface entropy flux, and thus more active outer convection. Meanwhile, a greater inertial stability helps the conversion from diabatic heating to kinetic energy. Furthermore, the progressively broadening of the tangential wind field will induce significant boundary layer imbalances. This unbalanced boundary layer process results in a supergradient wind zone that acts as an important mechanism for triggering and maintaining deep convection. In short, different behaviors of balanced and unbalanced processes associated with the initial wind profile lead to different development rates of the secondary eyewall.
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  • 42
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    Publication Date: 2018-03-05
    Description: We used daily maximum temperature data (1986–2100) from the COSMO-CLM (COnsortium for Small-scale MOdeling in CLimate Mode) regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events (EMTEs) with the intensity–area–duration method. Between 1986 and 2005 (reference period), the frequency, intensity, and coverage of EMTEs are 1330–1680 times yr –1 , 31.4–33.3°C, and 1.76–3.88 million km 2 , respectively. The center of the most severe EMTEs is located in central China and 179.5–392.8 million people are exposed to EMTEs annually. Relative to 1986–2005, the frequency, intensity, and coverage of EMTEs increase by 1.13–6.84, 0.32–1.50, and 15.98%–30.68%, respectively, under 1.5°C warming; under 2.0°C warming, the increases are 1.73–12.48, 0.64–2.76, and 31.96%–50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5°C warming, one in North China and the other in Southwest China. Under 2.0°C warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0°C warming, population exposure is projected to increase by 23.2%–39.2% and 26.6%–48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0°C warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0°C will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5°C.
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  • 43
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    Publication Date: 2018-03-05
    Description: The available agro-climate resources that can be absorbed and converted into dry matter could directly affect crop growth and yield under climate change. Knowledge of the average amount and stability of available agro-climate resources for maize in the main cropping regions of China under climate change is essential for farmers and advisors to optimize cropping choices and develop adaptation strategies under limited resources. In this study, the three main maize cropping regions in China—the North China spring maize region (NCS), the Huanghuaihai summer maize region (HS), and the Southwest China mountain maize region (SCM)—were selected as study regions. Based on observed solar radiation, temperature, and precipitation data, we analyzed the spatial distributions and temporal trends in the available agro-climate resources for maize during 1981–2010. During this period, significantly prolonged climatological growing seasons for maize [3.3, 2.0, and 4.7 day (10 yr) –1 in NCS, HS, and SCM] were found in all three regions. However, the spatiotemporal patterns of the available agro-climate resources differed among the three regions. The available heating resources for maize increased significantly in the three regions, and the rates of increase were higher in NCS [95.5°C day (10 yr)–1] and SCM [93.5°C day (10 yr) –1 ] than that in HS [57.7°C day (10 yr) –1 ]. Meanwhile, decreasing trends in the available water resources were found in NCS [–5.3 mm (10 yr) –1 ] and SCM [–5.8 mm (10 yr) –1 ], whereas an increasing trend was observed in HS [3.0 mm (10 yr) –1 ]. Increasing trends in the available radiation resources were found in NCS [20.9 MJ m –2 (10 yr) –1 ] and SCM [25.2 MJ m –2 (10 yr) –1 ], whereas a decreasing trend was found in HS [11.6 MJ m –2 (10 yr) –1 ]. Compared with 1981–90, the stability of all three resource types decreased during 1991–2000 and 2001–10 in the three regions. More consideration should be placed on the extreme events caused by more intense climate fluctuations. The results can provide guidance in the development of suitable adaptations to climate change in the main maize cropping regions in China.
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  • 44
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    Publication Date: 2018-03-05
    Description: We analyzed the structure and evolution of turbulent transfer and the wind profile in the atmospheric boundary layer in relation to aerosol concentrations during an episode of heavy haze pollution from 6 December 2016 to 9 January 2017. The turbulence data were recorded at Peking University’s atmospheric science and environment observation station. The results showed a negative correlation between the wind speed and the PM 2.5 concentration. The turbulence kinetic energy was large and showed obvious diurnal variations during unpolluted (clean) weather, but was small during episodes of heavy haze pollution. Under both clean and heavy haze conditions, the relation between the non-dimensional wind components and the stability parameter z / L followed a 1/3 power law, but the normalized standard deviations of the wind speed were smaller during heavy pollution events than during clean periods under near-neutral conditions. Under unstable conditions, the normalized standard deviation of the potential temperature σ θ /| θ * | was related to z / L , roughly following a –1/3 power law, and the ratio during pollution days was greater than that during clean days. The three-dimensional turbulence energy spectra satisfied a –2/3 power exponent rate in the high-frequency band. In the low-frequency band, the wind velocity spectrum curve was related to the stability parameters under clear conditions, but was not related to atmospheric stratification under polluted conditions. In the dissipation stage of the heavy pollution episode, the horizontal wind speed first started to increase at high altitudes and then gradually decreased at lower altitudes. The strong upward motion during this stage was an important dynamic factor in the dissipation of the heavy haze.
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  • 45
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    Publication Date: 2018-03-05
    Description: A 42-year-old man had an unstable Jefferson type IV atlas fracture with unilateral vertebral artery occlusion after a diving accident. We performed C1-ring reconstruction with a crosslink rod and C2 fixation to directly reduce the fracture fissure. Within 6 h, cerebellar hemisphere infarction developed. After decompressive craniectomy, duroplasty, and release of the vertebral artery occlusion caused by the transfixing rod, a postoperative computed tomography angiogram showed that blood flow in the right vertebral artery improved. We suggest cautiously inserting screws into the fractured C1 lateral mass and gently tightening the crosslink rod to prevent distal migration of a thrombus.
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  • 46
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    Publication Date: 2018-03-05
    Description: Background The aim of this retrospective study was to investigate the long-term seizure control and antiepileptic drug (AED) prescriptions, as well as identifying predictors of seizure(s) before and after surgery in a population-based cohort of operated intracranial meningioma patients. Methods A total of 113 consecutive adult (〉 18 years old) patients with newly diagnosed meningioma operated at the Karolinska University Hospital between 2006 and 2008 were included and followed up until the end of 2015. Data on seizure activity and AED prescriptions were obtained through chart review and telephone interview. Logistic regression and survival analysis were applied to identify risk factors for pre- and postoperative seizures. Results A total of 21/113 (18.6%) patients experienced seizures before surgery of which 8/21 (38.1%) went on to become seizure-free after surgery. Thirteen (14%) patients experienced new-onset seizures after surgery. The regression analysis revealed tumor diameter ≥ 3.5 cm as a risk factor for preoperative seizures (OR 3.83, 95% CI 1.14–12.87). Presence of headache (OR 0.19, 95% CI 0.05–0.76) and skull base tumor location (OR 0.14, 95% CI 0.04–0.44) decreased the risk of preoperative seizures. Postoperative seizures were associated with tumor diameter ≥ 3.5 cm (OR 2.65, 95% CI 1.06–6.62) and history of preoperative seizures (OR 3.50, 95% CI 1.55–7.90). Conclusion Seizures are common before and after intracranial meningioma surgery. Approximately one third of patients with preoperative seizures become seizure-free on long-term follow-up after surgery, while 14% experienced new-onset seizures after surgery. Larger tumor size, absence of headache, and non-skull base location were associated with preoperative seizures, while tumor size and preoperative seizures were associated with postoperative seizures.
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  • 47
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    Publication Date: 2018-03-05
    Description: Background Intraperitoneal pressure (IPP) counteracts the diversion of cerebrospinal fluid (CSF) from the cranial to the peritoneal compartment during ventriculoperitoneal shunting. Animal studies suggest that the intrinsic IPP exceeds the intraperitoneal hydrostatic pressure. The intrinsic IPP in mobile patients is relevant for shunt therapy, but data about it is not available. Methods The IPP was measured indirectly in 25 mobile subjects (13 female) by applying a standard intravesical pressure measurement technique. Measurements were carried out in reference to the navel (supine position) and the xiphoid (upright position). Results were adjusted for the intraperitoneal hydrostatic pressure and correlated afterward with general body measures. Results The corrected mean (SD) IPP measured in the supine position was 4.4 (4.5) cm H 2 O, and the mean (SD) upright IPP was 1.6 (7.8) cm H 2 O ( p  = 0.02). A positive correlation was found between the body mass index (BMI) and the IPP in the upright ( r  = 0.51) and supine ( r  = 0.65) body positions, and between the abdominal circumference and the IPP in the supine position ( r  = 0.63). Conclusions The intrinsic IPP in mobile subjects exceeds the intraperitoneal hydrostatic pressure. Thus, the intrinsic IPP counteracts the diversion of CSF into the peritoneal compartment. The intrinsic IPP is correlated with mobile patients’ general body measures.
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  • 48
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    Publication Date: 2018-03-05
    Print ISSN: 0001-6322
    Electronic ISSN: 1432-0533
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  • 49
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    Publication Date: 2018-03-05
    Description: Background There are no uniform guidelines regarding when to operate for Lumbar Spinal Stenosis (LSS). As we apply findings from clinical research from one population to the next, elucidating similarities or differences provides important context for the validity of extrapolating clinical outcomes. The aim of this study was to compare the morphological severity of lumbar spinal stenosis on preoperative MRI in patients undergoing decompressive surgery in Boston, USA, and Trondheim, Norway. Methods In this observational retrospective study, we compared morphological severity on MRI before surgical treatment between two propensity score-matched patient populations with single or two-level symptomatic LSS. We assessed the radiographic severity of LSS utilizing the Schizas classification (grade A to D). Results Following propensity score matching, demographics are balanced. In the Trondheim cohort, two levels decompression were present in 36.2% of the patients vs. 41.9% in Boston, ( p  = 0.396). There was no significant difference in grades A to D concerning central stenosis ( p  = 0.075). When dichotomized in mild/moderate (A/B) and severe /extreme (C/D), there were no significant differences in the rate of levels operated for high-grade stenosis (C/D), 67.6% in the Boston group compare to 78.1% in the Trondheim group ( p  = 0.088). Conclusions Trondheim, Norway, and Boston, US, have similar radiographic thresholds of LSS for offering surgery.
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  • 50
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    Publication Date: 2018-03-05
    Description: The western North Pacific anomalous anticyclone (WNPAC) is an important atmospheric circulation system that conveys El Niño impact on East Asian climate. In this review paper, various theories on the formation and maintenance of the WNPAC, including warm pool atmosphere–ocean interaction, Indian Ocean capacitor, a combination mode that emphasizes nonlinear interaction between ENSO and annual cycle, moist enthalpy advection/Rossby wave modulation, and central Pacific SST forcing, are discussed. It is concluded that local atmosphere–ocean interaction and moist enthalpy advection/Rossby wave modulation mechanisms are essential for the initial development and maintenance of the WNPAC during El Niño mature winter and subsequent spring. The Indian Ocean capacitor mechanism does not contribute to the earlier development but helps maintain the WNPAC in El Niño decaying summer. The cold SST anomaly in the western North Pacific, although damped in the summer, also plays a role. An interbasin atmosphere–ocean interaction across the Indo-Pacific warm pool emerges as a new mechanism in summer. In addition, the central Pacific cold SST anomaly may induce the WNPAC during rapid El Niño decaying/La Niña developing or La Niña persisting summer. The near-annual periods predicted by the combination mode theory are hardly detected from observations and thus do not contribute to the formation of the WNPAC. The tropical Atlantic may have a capacitor effect similar to the tropical Indian Ocean.
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  • 51
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    Publication Date: 2018-03-05
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  • 52
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    Publication Date: 2018-03-05
    Description: Background This study aims to assess surgical outcome in brain tumor surgery using patient reported outcome measures (PROMs) and to compare their results with traditional clinical outcome measurements. Method Neuro-oncological patients undergoing surgical removal for the lesion were enrolled; MOCA test, PROMs (EUROHIS-QoL, PGWB-S, WHODAS-12), and the clinical scale Karnofsky Performance Status (KPS) were administered to evaluate respectively cognitive status, quality of life, well-being, disability, and functional status before surgery and at 3-month follow-up. Wilcoxon test was performed to evaluate the longitudinal change of test scores, the smallest detectable difference to classify the change of patients in PROMs, the Cohen kappa to investigate the concordance between KPS and PROMs in classifying the patients’ change, and Mann-Whitney U test to compare patients with complications and no complications. Results A total of 101 patients were enrolled (54 woman, mean age 50.2 ± 14.1, range 20–85): psychological well-being improved at follow-up; 95 patients (94.1%) were improved/unchanged and 6 (5.9%) were worsened according to PROMs; functional status measured with KPS had a slight agreement with quality of life and disability and no agreement with psychological well-being questionnaires; patients with complications had a greater worsening in KPS. Conclusions According to PROMs measuring QoL, disability, and psychological well-being, most of the patients were improved/unchanged after surgery. Since PROMs and KPS detect different aspects of the patients’ health status, PROMs should be integrated in surgical outcome evaluation. Furthermore, their association with complications and with other clinical and subjective variables that could influence patient’s perception of health status should be investigated.
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  • 53
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    Publication Date: 2018-03-05
    Description: Background Wound healing impairment is a serious problem in surgical disciplines which may be associated with chronic morbidity, increased cost and patient discomfort. Here we aimed to investigate the relevance of bacterial colonisation on suture material using polymerase chain reaction (PCR) to detect and taxonomically classify bacterial DNA in patients with and without wound healing problems after routine neurosurgical procedures. Methods Repeat surgery was performed in 25 patients with wound healing impairment and in 38 patients with well-healed wounds. To determine the presence of bacteria, a 16S rDNA-based PCR detection method was applied. Fragments of 500 bp were amplified using universal primers which target hypervariable regions within the bacterial 16S rRNA gene. Amplicons were separated from each other by single-strand conformation polymorphism (SSCP) analysis, and finally classified using Sanger sequencing. Results PCR/SSCP detected DNA of various bacteria species on suture material in 10/38 patients with well-healed wounds and in 12/25 patients with wound healing impairment including Staphylococcus aureus , Staphylococcus epidermidis , Propionibacterium acnes and Escherichia coli . Microbiological cultures showed bacterial growth in almost all patients with wound healing impairment and positive results in PCR/SSCP (10/12), while this was the case in only one patient with a well-healed wound (1/10). Conclusions Colonisation of suture material with bacteria occurs in a relevant portion of patients with and without wound healing impairment after routine neurosurgical procedures. Suture material may provide a nidus for bacteria and subsequent biofilm formation. Most likely, however, such colonisation of sutures is not a general primer for subsequent wound infection.
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  • 54
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    Publication Date: 2018-03-05
    Description: Background Overall (OS) and progression-free survival (PFS) of patients undergoing spinal ependymoma resection has been frequently reported. Contrarily, OS and PFS of purely intramedullary ependymomas have not been clearly determined yet. Methods The data of 37 patients undergoing resection of an intramedullary ependymoma (IE) from January 2000 to December 2016 were analysed retrospectively. Results The mean age was 46 years. The male:female ratio was 24:13. The median duration of symptoms was 12 months. Sixty-two per cent of ependymomas were in the cervical, 24% in the thoracic, and 14% in the conus region in our series. The median volume was 1.3 ml. A syrinx was found in 49% and a cyst in 32%. GTR was achieved in 89%, STR in three (8%), and PR in one patient (3%). Median follow-up was 114 months. PFS was 87%, 82%, and 82% at 5, 10, and 15 years, respectively. OS was 97%, 88%, and 63% at 5, 10, and 15 years, respectively. There was a significant difference in PFS depending on the extent of resection and in OS depending on the pre-operative clinical status. There was no significant difference in OS and PFS regarding the other examined influencing factors. Conclusion GTR resection was the most important factor influencing PFS. According to our results OS of IEs is much worse than that of spinal ependymomas. Our analysis confirms that patients with good pre-operative (McCormick grade 1 and 2) clinical status have significantly better OS than patients with McCormick grade 3 and higher.
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  • 55
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    Publication Date: 2018-03-05
    Description: Introduction Drug-resistant essential tremor (ET) can benefit from open standard stereotactic procedures, such as deep-brain stimulation or radiofrequency thalamotomy. Non-surgical candidates can be offered either high-focused ultrasound (HIFU) or radiosurgery (RS). All procedures aim to target the same thalamic site, the ventro-intermediate nucleus (e.g., Vim). The mechanisms by which tremor stops after Vim RS or HIFU remain unknown. We used voxel-based morphometry (VBM) on pretherapeutic neuroimaging data and assessed which anatomical site would best correlate with tremor arrest 1 year after Vim RS. Methods Fifty-two patients (30 male, 22 female; mean age 71.6 years, range 49–82) with right-sided ET benefited from left unilateral Vim RS in Marseille, France. Targeting was performed in a uniform manner, using 130 Gy and a single 4-mm collimator. Neurological (pretherapeutic and 1 year after) and neuroimaging (baseline) assessments were completed. Tremor score on the treated hand (TSTH) at 1 year after Vim RS was included in a statistical parametric mapping analysis of variance (ANOVA) model as a continuous variable with pretherapeutic neuroimaging data. Pretherapeutic gray matter density (GMD) was further correlated with TSTH improvement. No a priori hypothesis was used in the statistical model. Results The only statistically significant region was right Brodmann area (BA) 18 (visual association area V2, p  = 0.05, cluster size K c  = 71). Higher baseline GMD correlated with better TSTH improvement at 1 year after Vim RS (Spearman’s rank correlation coefficient = 0.002). Conclusions Routine baseline structural neuroimaging predicts TSTH improvement 1 year after Vim RS. The relevant anatomical area is the right visual association cortex (BA 18, V2). The question whether visual areas should be included in the targeting remains open.
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  • 56
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    Publication Date: 2018-03-05
    Print ISSN: 0001-6322
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  • 57
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  • 58
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  • 59
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    Publication Date: 2018-03-05
    Print ISSN: 0001-6322
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  • 60
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    Publication Date: 2018-03-05
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  • 61
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  • 62
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    Publication Date: 2018-03-05
    Description: The exact mechanism underlying amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) associated with the GGGGCC repeat expansion in C9orf72 is still unclear. Two gain-of-function mechanisms are possible: repeat RNA toxicity and dipeptide repeat protein (DPR) toxicity. We here dissected both possibilities using a zebrafish model for ALS. Expression of two DPRs, glycine–arginine and proline–arginine, induced a motor axonopathy. Similarly, expanded sense and antisense repeat RNA also induced a motor axonopathy and formed mainly cytoplasmic RNA foci. However, DPRs were not detected in these conditions. Moreover, stop codon-interrupted repeat RNA still induced a motor axonopathy and a synergistic role of low levels of DPRs was excluded. Altogether, these results show that repeat RNA toxicity is independent of DPR formation. This RNA toxicity, but not the DPR toxicity, was attenuated by the RNA-binding protein Pur-alpha and the autophagy-related protein p62. Our findings demonstrate that RNA toxicity, independent of DPR toxicity, can contribute to the pathogenesis of C9orf72 -associated ALS/FTD.
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  • 63
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    Publication Date: 2018-03-05
    Description: Hexanucleotide repeat expansions in C9orf72 are the most common genetic cause of amyotrophic lateral sclerosis (C9 ALS). The main hypothesized pathogenic mechanisms are C9orf72 haploinsufficiency and/or toxicity from one or more of bi-directionally transcribed repeat RNAs and their dipeptide repeat proteins (DPRs) poly-GP, poly-GA, poly-GR, poly-PR and poly-PA. Recently, nuclear import and/or export defects especially caused by arginine-containing poly-GR or poly-PR have been proposed as significant contributors to pathogenesis based on disease models. We quantitatively studied and compared DPRs, nuclear pore proteins and C9orf72 protein in clinically related and clinically unrelated regions of the central nervous system, and compared them to phosphorylated TDP-43 (pTDP-43), the hallmark protein of ALS. Of the five DPRs, only poly-GR was significantly abundant in clinically related areas compared to unrelated areas ( p  〈 0.001), and formed dendritic-like aggregates in the motor cortex that co-localized with pTDP-43 ( p  〈 0.0001). While most poly-GR dendritic inclusions were pTDP-43 positive, only 4% of pTDP-43 dendritic inclusions were poly-GR positive. Staining for arginine-containing poly-GR and poly-PR in nuclei of neurons produced signals that were not specific to C9 ALS. We could not detect significant differences of nuclear markers RanGap, Lamin B1, and Importin β1 in C9 ALS, although we observed subtle nuclear changes in ALS, both C9 and non-C9, compared to control. The C9orf72 protein itself was diffusely expressed in cytoplasm of large neurons and glia, and nearly 50% reduced, in both clinically related frontal cortex and unrelated occipital cortex, but not in cerebellum. In summary, sense-encoded poly-GR DPR was unique, and localized to dendrites and pTDP43 in motor regions of C9 ALS CNS. This is consistent with new emerging ideas about TDP-43 functions in dendrites.
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  • 64
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    Publication Date: 2018-03-05
    Description: The popular methods to estimate wave height with high-frequency (HF) radar depend on the integration over the second-order spectral region and thus may come under from even not strong external interference. To improve the accuracy and increase the valid detection range of the wave height measurement, particularly by the smallaperture radar, it is turned to singular peaks which often exceed the power of other frequency components. The power of three kinds of singular peaks, i.e., those around ±1, ± and ± times the Bragg frequency, are retrieved from a one-month-long radar data set collected by an ocean state monitoring and analyzing radar, model S (OSMAR-S), and in situ buoy records are used to make some comparisons. The power response to a wave height is found to be described with a new model quite well, by which obvious improvement on the wave height estimation is achieved. With the buoy measurements as reference, a correlation coefficient is increased to 0.90 and a root mean square error (RMSE) is decreased to 0.35 m at the range of 7.5 km compared with the results by the second-order method. The further analysis of the fitting performance across range suggests that the peak has the best fit and maintains a good performance as far as 40 km. The correlation coefficient is 0.78 and the RMSE is 0.62 m at 40 km. These results show the effectiveness of the new empirical method, which opens a new way for the wave height estimation with the HF radar.
    Print ISSN: 0253-505X
    Electronic ISSN: 1869-1099
    Topics: Geosciences , Physics
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    Publication Date: 2018-03-05
    Description: The natural gas generation process is simulated by heating source rocks of the Yacheng Formation, including the onshore-offshore mudstone and coal with kerogens of Type II2-III in the Qiongdongnan Basin. The aim is to quantify the natural gas generation from the Yacheng Formation and to evaluate the geological prediction and kinetic parameters using an optimization procedure based on the basin modeling of the shallow-water area. For this, the hydrocarbons produced have been grouped into four classes (C 1 C 2 C 3 and C 4-6 ). The results show that the onset temperature of methane generation is predicted to occur at 110°C during the thermal history of sediments since 5.3 Ma by using data extrapolation. The hydrocarbon potential for ethane, propane and heavy gaseous hydrocarbons (C 4-6 ) is found to be almost exhausted at geological temperature of 200°C when the transformation ratio (TR) is over 0.8, but for which methane is determined to be about 0.5 in the shallow-water area. In contrast, the end temperature of the methane generation in the deep-water area was over 300°C with a TR over 0.8. It plays an important role in the natural gas exploration of the deep-water basin and other basins in the broad ocean areas of China. Therefore, the natural gas exploration for the deep-water area in the Qiongdongnan Basin shall first aim at the structural traps in the Ledong, Lingshui and Beijiao sags, and in the forward direction of the structure around the sags, and then gradually develop toward the non-structural trap in the deep-water area basin of the broad ocean areas of China.
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  • 66
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    Publication Date: 2018-03-05
    Print ISSN: 0256-1530
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  • 67
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    Publication Date: 2018-03-05
    Description: Wave ray theory is employed to study features of propagation pathways (rays) of vortex Rossby waves in typhoons with asymmetric basic flow, where the tangential asymmetric basic flow is constructed by superimposing the wavenumber-1 perturbation flow on the symmetric basic flow, and the radial basic flow is derived from the non-divergence equation. Results show that, in a certain distance, the influences of the asymmetry in the basic flow on group velocities and slopes of rays of vortex Rossby waves are mainly concentrated near the radius of maximum wind (RMW), whereas it decreases outside the RMW. The distributions of radial and tangential group velocities of the vortex Rossby waves in the asymmetric basic flow are closely related to the azimuth location of the maximum speed of the asymmetric basic flow, and the importance of radial and tangential basic flow on the group velocities would change with radius. In addition, the stronger asymmetry in the basic flow always corresponds to faster outward energy propagation of vortex Rossby waves. In short, the group velocities, and thereby the wave energy propagation and vortex Rossby wave ray slope in typhoons, would be changed by the asymmetry of the basic flow.
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  • 68
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    Publication Date: 2018-03-05
    Description: The geometric characteristics of tropical cyclone (TC) eyes before landfall in South China are examined using ground-based radar reflectivity. It is found that the median and mean eye area decrease with TC intensity, except for the severe typhoon category, and the eye size increases with height. The increasing rate of eye size is relatively greater in upper layers. Moreover, the ratio of eye size change in the vertical direction does not correlate with TC intensity. No relationship is presented between the ratio of eye size change in the vertical direction and the vertical wind shear. No relationship between the vertical change in eye size and the eye size at a certain level is found, inconsistent with other studies. No relationship exists between the vertical change in eye size and the intensity tendency. The eye roundness values range mainly from 0.5 to 0.7, and more intense TCs generally have eyes that are more circular.
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  • 69
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    Publication Date: 2018-03-05
    Description: Future changes in the 50-yr return level for temperature and precipitation extremes over mainland China are investigated based on a CMIP5 multi-model ensemble for RCP2.6, RCP4.5 and RCP8.5 scenarios. The following indices are analyzed: TXx and TNn (the annual maximum and minimum of daily maximum and minimum surface temperature), RX5day (the annual maximum consecutive 5-day precipitation) and CDD (maximum annual number of consecutive dry days). After first validating the model performance, future changes in the 50-yr return values and return periods for these indices are investigated along with the inter-model spread. Multi-model median changes show an increase in the 50-yr return values of TXx and a decrease for TNn, more specifically, by the end of the 21st century under RCP8.5, the present day 50-yr return period of warm events is reduced to 1.2 yr, while extreme cold events over the country are projected to essentially disappear. A general increase in RX5day 50-yr return values is found in the future. By the end of the 21st century under RCP8.5, events of the present RX5day 50-yr return period are projected to reduce to 〈 10 yr over most of China. Changes in CDD-50 show a dipole pattern over China, with a decrease in the values and longer return periods in the north, and vice versa in the south. Our study also highlights the need for further improvements in the representation of extreme events in climate models to assess the future risks and engineering design related to large-scale infrastructure in China.
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    Publication Date: 2018-03-05
    Description: The application of numerical weather prediction (NWP) products is increasing dramatically. Existing reports indicate that ensemble predictions have better skill than deterministic forecasts. In this study, numerical ensemble precipitation forecasts in the TIGGE database were evaluated using deterministic, dichotomous (yes/no), and probabilistic techniques over Iran for the period 2008–16. Thirteen rain gauges spread over eight homogeneous precipitation regimes were selected for evaluation. The Inverse Distance Weighting and Kriging methods were adopted for interpolation of the prediction values, downscaled to the stations at lead times of one to three days. To enhance the forecast quality, NWP values were post-processed via Bayesian Model Averaging. The results showed that ECMWF had better scores than other products. However, products of all centers underestimated precipitation in high precipitation regions while overestimating precipitation in other regions. This points to a systematic bias in forecasts and demands application of bias correction techniques. Based on dichotomous evaluation, NCEP did better at most stations, although all centers overpredicted the number of precipitation events. Compared to those of ECMWF and NCEP, UKMO yielded higher scores in mountainous regions, but performed poorly at other selected stations. Furthermore, the evaluations showed that all centers had better skill in wet than in dry seasons. The quality of post-processed predictions was better than those of the raw predictions. In conclusion, the accuracy of the NWP predictions made by the selected centers could be classified as medium over Iran, while post-processing of predictions is recommended to improve the quality.
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  • 71
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    Publication Date: 2018-03-05
    Description: Variations in the high-frequency oscillations of tropical cyclones (TCs) over the western North Pacific (WNP) are studied in numerical model simulations. Power spectrum analysis of maximum wind speeds at 10 m (MWS 10 ) from an ensemble of 15 simulated TCs shows that oscillations are significant for all TCs. The magnitudes of oscillations in MWS 10 are similar in the WNP and South China Sea (SCS); however, the mean of the averaged significant periods in the SCS (1.93 h) is shorter than that in the open water of the WNP (2.83 h). The shorter period in the SCS is examined through an ensemble of simulations, and a case simulation as well as a sensitivity experiment in which the continent is replaced by ocean for Typhoon Hagupit (2008). The analysis of the convergence efficiency within the boundary layer suggests that the shorter periods in the SCS are possibly due to the stronger terrain effect, which intensifies convergence through greater friction. The enhanced convergence strengthens the disturbance of the gradient and thermal wind balances, and then contributes to the shorter oscillation periods in the SCS.
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    Publication Date: 2018-03-05
    Description: Soil enthalpy ( H ) contains the combined effects of both soil moisture ( w ) and soil temperature ( T ) in the land surface hydrothermal process. In this study, the sensitivities of H to w and T are investigated using the multi-linear regression method. Results indicate that T generally makes positive contributions to H , while w exhibits different (positive or negative) impacts due to soil ice effects. For example, w negatively contributes to H if soil contains more ice; however, after soil ice melts, w exerts positive contributions. In particular, due to lower w interannual variabilities in the deep soil layer (i.e., the fifth layer), H is more sensitive to T than to w . Moreover, to compare the potential capabilities of H , w and T in precipitation ( P ) prediction, the Huanghe–Huaihe Basin (HHB) and Southeast China (SEC), with similar sensitivities of H to w and T , are selected. Analyses show that, despite similar spatial distributions of H–P and T–P correlation coefficients, the former values are always higher than the latter ones. Furthermore, H provides the most effective signals for P prediction over HHB and SEC, i.e., a significant leading correlation between May H and early summer (June) P . In summary, H , which integrates the effects of T and w as an independent variable, has greater capabilities in monitoring land surface heating and improving seasonal P prediction relative to individual land surface factors (e.g., T and w ).
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    Publication Date: 2018-03-05
    Description: Severe weather reports and composite radar reflectivity data from 2010–14 over North China were used to analyze the distribution of severe convective wind (SCW) events and their organizational modes of radar reflectivity. The six organizational modes for SCW events (and their proportions) were cluster cells (35.4%), squall lines (18.4%), nonlinear-shaped systems (17.8%), broken lines (11.6%), individual cells (1.2%), and bow echoes (0.5%). The peak month for both squall lines and broken lines was June, whereas it was July for the other four modes. The highest numbers of SCW events were over the mountains, which were generally associated with disorganized systems of cluster cells. In contrast, SCW associated with linear systems occurred mainly over the plains, where stations recorded an average of less than one SCW event per year. Regions with a high frequency of SCW associated with nonlinear-shaped systems also experienced many SCW events associated with squall lines. Values of convective available potential energy, precipitable water, 0–3-km shear, and 0–6-km shear, were demonstrably larger over the plains than over the mountains, which had an evident effect on the organizational modes of SCW events. Therefore, topography may be an important factor in the organizational modes for SCW events over North China.
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  • 74
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    Publication Date: 2018-03-05
    Description: Using observational data and the pre-industrial simulations of 19 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), the El Niño (EN) and La Niña (LN) events in positive and negative Pacific Decadal Oscillation (PDO) phases are examined. In the observational data, with EN (LN) events the positive (negative) SST anomaly in the equatorial eastern Pacific is much stronger in positive (negative) PDO phases than in negative (positive) phases. Meanwhile, the models cannot reasonably reproduce this difference. Besides, the modulation of ENSO frequency asymmetry by the PDO is explored. Results show that, in the observational data, EN is 300% more (58% less) frequent than LN in positive (negative) PDO phases, which is significant at the 99% confidence level using the Monte Carlo test. Most of the CMIP5 models exhibit results that are consistent with the observational data.
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  • 75
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    Publication Date: 2018-03-05
    Description: The characteristics of tropical cyclone (TC) extreme rainfall events over Hainan Island from 1969 to 2014 are analyzed from the viewpoint of the TC maximum daily rainfall (TMDR) using daily station precipitation data from the Meteorological Information Center of the China Meteorological Administration, TC best-track data from the Shanghai Typhoon Institute, and NCEP/NCAR reanalysis data. The frequencies of the TMDR reaching 50, 100 and 250 mm show a decreasing trend [−0.7 (10 yr) −1 ], a weak decreasing trend [−0.2 (10 yr) −1 ] and a weak increasing trend [0.1 (10 yr) −1 ], respectively. For seasonal variations, the TMDR of all intensity grades mainly occurs from July to October, with the frequencies of TMDR - 50 mm and - 100 mm peaking in September and the frequency of TMDR - 250 mm [TC extreme rainstorm (TCER) events] peaking in August and September. The western region (Changjiang) of the Island is always the rainfall center, independent of the intensity or frequencies of different intensity grades. The causes of TCERs are also explored and the results show that topography plays a key role in the characteristics of the rainfall events. TCERs are easily induced on the windward slopes of Wuzhi Mountain, with the coordination of TC tracks and TC wind structure. A slower speed of movement, a stronger TC intensity and a farther westward track are all conducive to extreme rainfall events. A weaker northwestern Pacific subtropical high is likely to make the 500-hPa steering flow weaker and results in slower TC movement, whereas a stronger South China Sea summer monsoon can carry a higher moisture flux. These two environmental factors are both favorable for TCERs.
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    Publication Date: 2018-03-05
    Description: The present study investigates the interannual variation of June–November synoptic disturbance activity over the western North Pacific (WNP) and its relationship with large-scale circulation for the period 1958–2014. Two leading modes of eddy kinetic energy for the disturbance variability over the WNP are obtained by EOF analysis, characterized by anomalous eddy kinetic energy over the subtropical WNP and around the Philippines, respectively. These modes explain a large portion of the interannual variance of synoptic disturbance activity over the WNP. Both are associated with lower-level cyclonic anomalies, but with different locations: over the subtropical WNP for the first mode and over the South China Sea for the second mode. Considering the impact of ENSO on synoptic disturbance activity over the WNP, we repeat the analyses after removing the effect of ENSO, which is simply defined as the components linearly regressed onto the Niño3.4 index, and find similar results, suggesting that the leading modes and their relationships with large-scale circulation exist without SST effects. Further analyses suggest that the meridional shear of zonal winds caused by cyclonic anomalies is crucial for maintaining the leading modes through barotropic conversion.
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  • 77
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    Publication Date: 2018-03-05
    Description: A numerical experiment was performed using the Weather Research and Forecasting (WRF) model to analyze the generation and propagation of inertia-gravity waves during an orographic rainstorm that occurred in the Sichuan area on 17 August 2014. To examine the spatial and temporal structures of the inertia-gravity waves and identify the wave types, three wavenumber-frequency spectral analysis methods (Fourier analysis, cross-spectral analysis, and wavelet cross-spectrum analysis) were applied. During the storm, inertia-gravity waves appeared at heights of 10–14 km, with periods of 80–100 min and wavelengths of 40–50 km. These waves were generated over a mountain and propagated eastward at an average speed of 15–20 m s −1 . Meanwhile, comparison between the reconstructed inertia-gravity waves and accumulated precipitation showed there was a mutual promotion process between them. The Richardson number and Scorer parameter were used to demonstrate that the eastward-moving inertia-gravity waves were trapped in an effective atmospheric ducting zone with favorable reflector and critical level conditions, which were the primary causes of the long lives of the waves. Finally, numerical experiments to test the sensitivity to terrain and diabatic heating were conducted, and the results suggested a cooperative effect of terrain and diabatic heating contributed to the propagation and enhancement of the waves.
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    Publication Date: 2018-03-05
    Description: This study investigates the structure and propagation of intraseasonal sea surface temperature (SST) variability in the South China Sea (SCS) on the 30–60-day timescale during boreal summer (May–September). TRMM-based SST, GODAS oceanic reanalysis and ERA-Interim atmospheric reanalysis datasets from 1998 to 2013 are used to examine quantitatively the atmospheric thermodynamic and oceanic dynamic mechanisms responsible for its formation. Power spectra show that the 30–60-day SST variability is predominant, accounting for 60% of the variance of the 10–90-day variability over most of the SCS. Composite analyses demonstrate that the 30–60-day SST variability is characterized by the alternate occurrence of basin-wide positive and negative SST anomalies in the SCS, with positive (negative) SST anomalies accompanied by anomalous northeasterlies (southwesterlies). The transition and expansion of SST anomalies are driven by the monsoonal trough–ridge seesaw pattern that migrates northward from the equator to the northern SCS. Quantitative diagnosis of the composite mixed-layer heat budgets shows that, within a strong 30–60-day cycle, the atmospheric thermal forcing is indeed a dominant factor, with the mixed-layer net heat flux (MNHF) contributing around 60% of the total SST tendency, while vertical entrainment contributes more than 30%. However, the entrainment-induced SST tendency is sometimes as large as the MNHF-induced component, implying that ocean processes are sometimes as important as surface fluxes in generating the 30–60-day SST variability in the SCS.
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  • 79
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    Publication Date: 2018-03-05
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  • 80
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    Publication Date: 2018-03-05
    Description: In previous work, a significant relationship was identified between the meridional displacement of the Asian westerly jet (JMD) and the Silk Road Pattern (SRP) in summer. The present study reveals that this relationship is robust in northward JMD years but absent in southward JMD years. In other words, the amplitude of the SRP increases with northward displacement of the jet but shows little change with southward displacement. Further analysis indicates that, in northward JMD years, the Rossby wave source (RWS) anomalies, which are primarily contributed by the planetary vortex stretching, are significantly stronger around the entrance of the Asian jet, i.e., the Mediterranean Sea–Caspian Sea area, with the spatial distribution being consistent with that related to the SRP. By contrast, in southward JMD years, the RWS anomalies are much weaker. Therefore, this study suggests that the RWS plays a crucial role in inducing the asymmetry of the JMD–SRP relationship. The results imply that climate anomalies may be stronger in strongly northward-displaced JMD years due to the concurrence of the JMD and SRP, and thus more attention should be paid to these years.
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  • 81
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    Publication Date: 2018-03-05
    Description: Few studies have specifically focused on the validation and spatiotemporal distribution of planetary boundary layer height (PBLH) and relative humidity (RH) data in China. In this analysis, continuous PBLH and surface-level RH data simulated from GEOS-5 between 2004 and 2012, were validated against ground-based observations. Overall, the simulated RH was consistent with the statistical data from meteorological stations, with a correlation coefficient of 0.78 and a slope of 0.9. However, the simulated PBLH was underestimated compared to LIDAR data by a factor of approximately two, which was primarily because of poor simulation in late summer and early autumn. We further examined the spatiotemporal distribution characteristics of two factors in four regions—North China, South China, Northwest China, and the Tibetan Plateau. The results showed that the annual PBLH trends in all regions were fairly moderate but sensitive to solar radiation and precipitation, which explains why the PBLH values were ranked in order from largest to smallest as follows: Tibetan Plateau, Northwest China, North China, and South China. Strong seasonal variation of the PBLH exhibited high values in summer and low values in winter, which was also consistent with the turbulent vertical exchange. Not surprisingly, the highest RH in South China and the lowest RH in desert areas of Northwest China (less than 30%). Seasonally, South China exhibited little variation, whereas Northwest China exhibited its highest humidity in winter and lowest humidity in spring, the maximum values in the other regions were obtained from July to September.
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  • 82
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    Publication Date: 2018-03-06
    Description: To meet the environmental challenges that are presently confronting society, the narrow focus on agricultural production needs to be altered to one that places equal value on the generation of crucial ecosystem services. Current research shows that perennial intercropping systems such as agroforestry may be a feasible alternative. Based on studies during the establishment of edible forest gardens in 12 participating farms in Sweden, this paper explores the potential of utilizing multi-strata designs for food production in temperate, high-income countries. Design and species composition of such gardens, types of food they provide, and how they would best fit into the present landscape are discussed. Factors for success and major problems related to the establishment are shared. Potential benefits were found to be closely related to a thorough analysis of the social and ecological contexts before establishment. Characteristics of the site and goals of the garden need to guide species and design choices. If forest garden approaches to food production should contribute to more than local self-sufficiency, the gardens need to increase in scale. Marginal lands and transitions areas between different land uses may be appropriate. Large knowledge gaps concerning potential production, social and economic benefits, and agronomic issues were identified.
    Print ISSN: 0167-4366
    Electronic ISSN: 1572-9680
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 83
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    Publication Date: 2018-03-06
    Description: The published on-line ms “Carbon dynamics of cocoa agroforestry systems in Central Cameroon: afforestation of savannah as a sequestration opportunity.” ( https://doi.org/10.1007/s10457-017-0182-6 ) unfortunately bears some unit errors on soil organic C contents.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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    Springer
    Publication Date: 2018-03-06
    Description: Large seed banks in the soils of Mediterranean wood pastures can allow the composition of the understorey vegetation to adapt to changing conditions such as under-grazing, grazing exclusion and climate change. This three year study investigated the effect of grazing exclusion on the transient and persistent seed banks of 23 areas of a Mediterranean wood pasture of Quercus suber L., Q. ilex L. and Q. pubescens Willd. A canonical correspondence analysis was used to determine the effect of topo-climatic (elevation, aspect, slope, rainfall, temperature, tree coverage), soil (pH, soil texture, and soil nitrogen, phosphorus, lime and organic carbon content) and biodiversity (Shannon index, species richness index, and Pastoral Value) variables on the soil seed bank under grazed and ungrazed conditions. The size of the persistent seed bank increased with rainfall, grazing, and the available phosphorus content of the soil. Specific site by site grazing regimes could increase the abundance of legumes in the soil seed bank and the species richness and diversity of the understorey vegetation. These results can help guide the conservation management of this silvopastoral area.