bluuebunny/crossref_metadata_2025 huggingface dataset:
Issues and Challenges of Student Financing Systems in Africa: The Case of Tanzania
Authors: Kossey Masumbuko Mathew , Ishengoma Johnson Muchunguzi
Published: December 2017

This article investigates the challenges confronting student fnancing systems in Africa, with specifc reference to Tanzania’s Higher Education Students’ Loans Board (HESLB). It shows that the major challenges include limited resources, unemployment among loan benefciaries, increased loans applications, the lack of a national identifcation system, emigration of loan benefciaries, poor policy and legal frameworks, and corruption among HESLB staﬀ and loan benefciaries. The article recommends that the HESLB should diversify its sources of funding to reduce dependence on government; enforce loan repayment through legislation that enables direct reimbursement from benefciaries’ salaries; charge interest higher than the inﬂation rate; and embark on aggressive public education campaigns on the importance and benefts of the loan scheme and loan repayments. Cet article examine les défs auxquels sont confrontés les systèmes de fnancement de l’enseignement supérieur en Afrique, en prenant pour exemple le Comité de Prêts pour Etudiants de l’Enseignement Supérieur de Tanzanie (HESLB). Il montre que les défs principaux sont liés au manque de ressources et au chômage des bénéfciaires de prêts, à une augmentation des demandes de prêts, à l’absence d’un système d’identifcation national, à l’émigration des bénéfciaires de prêts, à l’inadaptation des politiques et des cadres légaux, et à la corruption du personnel de l’HESLB et des bénéfciaires de prêts. Cet article recommande que l’HESLB diversife ses sources de fnancement pour limiter sa dépendance vis-à-vis du gouvernement ; qu’il renforce le taux de remboursement des prêts au moyen d’une législation permettant un prélèvement direct sur le salaire des bénéfciaires ; qu’il charge des intérêts plus haut que l’inﬂation ; et qu’il mène une campagne agressive d’éducation du public sur l’importance et les bénéfces du système de prêts et de remboursements pour les étudiants.
I CINAPSE – I International Conference of Physical Activity and Health Promotion at School
Authors: Pontes Júnior Jose Airton , Catunda Ricardo , Garrido Nuno Domingos , Marques Adilson , Loureiro Adriano C. , Rombaldi Airton J. , Netto Americo Valdanha , Oliveira Amauri B. , Catrib Ana F. , Machado André A. , Pereira Beatriz O. , Carneiro Cleide , Guedes Dartagnan Pinto , Ferreira Heraldo S. , Pelarigo Jailton G. , Martins João F. , Fernández José R. , Melo José P. , Pereira Laércio , Gurgel Luilma , Maggi Luis , Neto Luiz Silva , Carvalho Mark , Soares Paula M. , Silva Romeu , Moreira Thereza M. , Borges Thiago T. , Barbosa Filho Valter
Published: December 2017

The papers published in the present supplement were submitted to the Scientific Commission of I CINAPSE - "I International Conference of Physical Activity and Health Promotion at School" held on November 17 to 19th, 2016, at the State University of Ceará, Fortaleza, Ceará-Brazil.
Community structure explains antibiotic resistance gene dynamics over a temperature gradient in soil
Authors: Dunivin Taylor K , Shade Ashley
Published: December 2017

Soils are reservoirs of antibiotic resistance genes, but dynamics of antibiotic resistance genes in the environment are largely unknown. Long-term disturbances offer extended opportunities to examine microbiome responses at scales relevant for both ecological and evolutionary processes, and therefore can be insightful for studying the dynamics of antibiotic resistance genes in the environment. We examined antibiotic resistance genes in soils overlying the underground coal seam fire in Centralia, PA, which has been burning since 1962. As the fire progresses, previously hot soils can recover to ambient temperatures, which creates a gradient of contemporary and historical fire impact. We examined metagenomes from fire-affected, recovered, and reference surface soils to examine gene-resolved dynamics of antibiotic resistance using a gene-targeted assembler. We targeted 35 distinct types of clinically-relevant antibiotic resistance genes and two horizontal gene transfer-related genes (intI and repA). We detected 17 antibiotic resistance genes in Centralia, including AAC6-Ia, adeB, bla_A, bla_B, bla_C, cmlA, dfra12, intI, sul2, tetA, tetW, tetX, tolC, vanA, vanH, vanX, and vanZ. The diversity and abundance of several antibiotic resistance genes (bla_A, bla_B, dfra12, tolC) decreased with soil temperature, and changes in ARGs could largely be explained by associated changes in community structure. We also observed sequence-specific dynamics along the temperature gradient and observed compositional shifts in bla_A, dfra12, and intI. These results suggest that increased temperatures can reduce soil antibiotic resistance genes but that this is largely due to a concomitant reduction in community-level diversity.
Collaborative Learning at the Boundaries: Hallmarks within a Rehabilitation Context
Authors: Christiansen Bjørg , Taasen Inger , Hagstrøm Nora , Hansen Kjellaug Kildal , Norenberg Dorte Lybye
Published: December 2017

The aim of the article is to shed light on how collaborative learning at the boundaries between professions plays out within a rehabilitation context. The study has an ethnographic design in the form of observation and interviews in two rehabilitation contexts. Findings showed that collaborative learning was stimulated when the professional groups made a concerted effort to acquire an overall perspective on the patient’s situation and requested and disseminated context-dependent expressions and knowledge about how the patient functioned. The “training” of patients on the ward served as an abstract boundary object amongst the staff functioning as a unifying resource in collaboration. The study exemplifies the learning potential when boundaries between professions become more open in an overlapping collaboration. This enables awareness of one’s own boundaries and of the fact that one had a wealth of shared knowledge. In addition, it entailed the learning of techniques and procedures from other professions, which augmented and developed one’s own professional repertoire.
Book review of: Metaheuristics for Business Analytics. A Decision Modeling Approach by Abraham Duarte, Manuel Laguna,and Rafael Martí
Authors: Makajić-Nikolić Dragana
Published: December 2017

Book review of:  Metaheuristics for Business Analytics. A Decision Modeling Approach by Abraham Duarte, Manuel Laguna,and Rafael Martí. Springer International Publishing, Series: EURO Advanced Tutorials on Operational Research, 2018, 136 pp. Hardcover ISBN: 978-3-319-68117-7, eBook ISBN: 978-3-319-68119-1
An Approach to Criteria Weights Determination by Integrating the DELPHI and the Adapted SWARA Methods
Authors: Karabasevic Darjan , Stanujkic Dragisa , Urosevic Snezana , Popovic Gabrijela , Maksimovic Mladjan
Published: December 2017

The process of evaluation and selection of personnel is characterized by defining a specific set of criteria. The process of defining and determining the weights of the criteria is a significant, because the evaluation and the final selection of personnel are carried out on the basis of the defined set of criteria. Therefore, this manuscript is aimed at creating a set of the sales managers’ evaluation criteria as well as defining the weights of such criteria. The survey sample was 79 domain experts in the field of the recruitment and selection of personnel. The proposed approach based on the integration of the Delphi technique and the adapted SWARA methods was successfully applied for the purpose of defining the weights of the criteria and completely  responded to the requirements in terms of defining the criteria and determining the weights of the criteria.
Nighttime Medium‐Scale Traveling Ionospheric Disturbances From Airglow Imager and Global Navigation Satellite Systems Observations
Authors: Huang Fuqing , Lei Jiuhou , Dou Xiankang , Luan Xiaoli , Zhong Jiahao
Published: December 2017

In this study, coordinated airglow imager, GPS total electron content (TEC), and Beidou geostationary orbit (GEO) TEC observations for the first time are used to investigate the characteristics of nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) over central China. The results indicated that the features of nighttime MSTIDs from three types of observations are generally consistent, whereas the nighttime MSTID features from the Beidou GEO TEC are in better agreement with those from airglow images as compared with the GPS TEC, given that the nighttime MSTID characteristics from GPS TEC are significantly affected by Doppler effect due to satellite movement. It is also found that there are three peaks in the seasonal variations of the occurrence rate of nighttime MSTIDs in 2016. Our study revealed that the Beidou GEO satellites provided fidelity TEC observations to study the ionospheric variability.
The Influence of Air‐Sea Fluxes on Atmospheric Aerosols During the Summer Monsoon Over the Tropical Indian Ocean
Authors: Zavarsky Alex , Booge Dennis , Fiehn Alina , Krüger Kirstin , Atlas Elliot , Marandino Christa
Published: December 2017

During the summer monsoon, the western tropical Indian Ocean is predicted to be a hot spot for dimethylsulfide emissions, the major marine sulfur source to the atmosphere, and an important aerosol precursor. Other aerosol relevant fluxes, such as isoprene and sea spray, should also be enhanced, due to the steady strong winds during the monsoon. Marine air masses dominate the area during the summer monsoon, excluding the influence of continentally derived pollutants. During the SO234‐2/235 cruise in the western tropical Indian Ocean from July to August 2014, directly measured eddy covariance DMS fluxes confirm that the area is a large source of sulfur to the atmosphere (cruise average 9.1 μmol m−2 d−1). The directly measured fluxes, as well as computed isoprene and sea spray fluxes, were combined with FLEXPART backward and forward trajectories to track the emissions in space and time. The fluxes show a significant positive correlation with aerosol data from the Terra and Suomi‐NPP satellites, indicating a local influence of marine emissions on atmospheric aerosol numbers.
Frictional Properties of Opalinus Clay: Implications for Nuclear Waste Storage
Authors: Orellana L. F. , Scuderi M. M. , Collettini C. , Violay M.
Published: December 2017

The kaolinite‐bearing Opalinus Clay (OPA) is the host rock proposed in Switzerland for disposal of radioactive waste. However, the presence of tectonic faults intersecting the OPA formation put the long‐term safety performance of the underground repository into question due to the possibility of earthquakes triggered by fault instability. In this paper, we study the frictional properties of the OPA shale. To do that, we have carried out biaxial direct shear experiments under conditions typical of nuclear waste storage. We have performed velocity steps (1–300 μm/s) and slide‐hold‐slide tests (1–3,000 s) on simulated fault gouge at different normal stresses (4–30 MPa). To establish the deformation mechanisms, we have analyzed the microstructures of the sheared samples through scanning electron microscopy. Our results show that peak (μpeak) and steady state friction (μss) range from 0.21 to 0.52 and 0.14 to 0.39, respectively, thus suggesting that OPA fault gouges are weak. The velocity dependence of friction indicates a velocity strengthening regime, with the friction rate parameter (a − b) that decreases with normal stress. Finally, the zero healing values imply a lack of restrengthening during interseismic periods. Taken together, if OPA fault reactivates, our experimental evidence favors an aseismic slip behavior, making the nucleation of earthquakes difficult, and long‐term weakness, resulting in stable fault creeping over geological times. Based on the results, our study confirms the seismic safety of the OPA formation for a nuclear waste repository.
Nonparametric Integrated Agrometeorological Drought Monitoring: Model Development and Application
Authors: Zhang Qiang , Li Qin , Singh Vijay P. , Shi Peijun , Huang Qingzhong , Sun Peng
Published: December 2017

Drought is a major natural hazard that has massive impacts on the society. How to monitor drought is critical for its mitigation and early warning. This study proposed a modified version of the multivariate standardized drought index (MSDI) based on precipitation, evapotranspiration, and soil moisture, i.e., modified multivariate standardized drought index (MMSDI). This study also used nonparametric joint probability distribution analysis. Comparisons were done between standardized precipitation evapotranspiration index (SPEI), standardized soil moisture index (SSMI), MSDI, and MMSDI, and real‐world observed drought regimes. Results indicated that MMSDI detected droughts that SPEI and/or SSMI failed to do. Also, MMSDI detected almost all droughts that were identified by SPEI and SSMI. Further, droughts detected by MMSDI were similar to real‐world observed droughts in terms of drought intensity and drought‐affected area. When compared to MMSDI, MSDI has the potential to overestimate drought intensity and drought‐affected area across China, which should be attributed to exclusion of the evapotranspiration components from estimation of drought intensity. Therefore, MMSDI is proposed for drought monitoring that can detect agrometeorological droughts. Results of this study provide a framework for integrated drought monitoring in other regions of the world and can help to develop drought mitigation.
Impact of Biomass Burning Aerosols on the Diurnal Cycle of Convective Clouds and Precipitation Over a Tropical Island
Authors: Hodzic Alma , Duvel Jean Philippe
Published: December 2017

A coupled weather‐aerosol model is used to study the effect of biomass burning aerosols on deep convection over the Borneo Island and surrounding oceans. Simulations are performed at the convection‐permitting scale (4 km) for 40 days during the boreal summer and include interactive fire emissions and the aerosol effect on radiative and microphysical processes. Intense burning occurs daily in the southern part of the island, and smoke propagates northward to regions of deep convection. The model captures well the observed diurnal cycle of precipitation and high cloud cover. Cloud microphysics and radiative aerosol impacts are considered separately. Modifications of the cloud microphysics by smoke aerosols reinforce deep convection near the central Borneo mountainous region. This reinforced convection is due to reduced shallow precipitation in the afternoon that leads to a warm planetary boundary layer anomaly at sunset enhancing deep convection at night. Aerosol absorptive properties strongly affect local and synoptic atmospheric responses. The radiative processes of moderately absorbing aerosols tend to reduce deep convection over most regions due to local surface cooling and atmosphere warming that increase the static stability. For more absorbing aerosols, however, the impact is reversed with increased nighttime convection over most regions. This is partly related to changes in the vertical water vapor divergence profiles that decrease the convergence toward Borneo for moderately absorbing aerosols and increase it for more absorbing ones. These changes in the synoptic circulation due to large‐scale aerosol perturbations are as important as local processes to explain the observed rainfall perturbation patterns.
Seasonal Progression of the Deposition of Black Carbon by Snowfall at Ny‐Ålesund, Spitsbergen
Authors: Sinha P. R. , Kondo Y. , Goto‐Azuma K. , Tsukagawa Y. , Fukuda K. , Koike M. , Ohata S. , Moteki N. , Mori T. , Oshima N. , Førland E. J. , Irwin M. , Gallet J.‐C. , Pedersen C. A.
Published: December 2017

Deposition of black carbon (BC) aerosol in the Arctic lowers snow albedo, thus contributing to warming in the region. However, the processes and impacts associated with BC deposition are poorly understood because of the scarcity and uncertainties of measurements of BC in snow with adequate spatiotemporal resolution. We sampled snowpack at two sites (11 m and 300 m above sea level) at Ny‐Ålesund, Spitsbergen, in April 2013. We also collected falling snow near the surface with a windsock from September 2012 to April 2013. The size distribution of BC in snowpack and falling snow was measured using a single‐particle soot photometer combined with a characterized nebulizer. The BC size distributions did not show significant variations with depth in the snowpack, suggesting stable size distributions in falling snow. The BC number and mass concentrations (CNBC and CMBC) at the two sites agreed to within 19% and 10%, respectively, despite the sites' different snow water equivalent (SWE) loadings. This indicates the small influence of the amount of SWE (or precipitation) on these quantities. Average CNBC and CMBC in snowpack and falling snow at nearly the same locations agreed to within 5% and 16%, after small corrections for artifacts associated with the sampling of the falling snow. This comparison shows that the dry deposition was a small contributor to the total BC deposition. CMBC were highest (2.4 ± 3.0 μg L−1) in December–February and lowest (1.2 ± 1.2 μg L−1) in September–November.
Sensitivity of Coupled Tropical Pacific Model Biases to Convective Parameterization in CESM1
Authors: Woelfle M. D. , Yu S. , Bretherton C. S. , Pritchard M. S.
Published: December 2017

Six month coupled hindcasts show the central equatorial Pacific cold tongue bias development in a GCM to be sensitive to the atmospheric convective parameterization employed. Simulations using the standard configuration of the Community Earth System Model version 1 (CESM1) develop a cold bias in equatorial Pacific sea surface temperatures (SSTs) within the first two months of integration due to anomalous ocean advection driven by overly strong easterly surface wind stress along the equator. Disabling the deep convection parameterization enhances the zonal pressure gradient leading to stronger zonal wind stress and a stronger equatorial SST bias, highlighting the role of pressure gradients in determining the strength of the cold bias. Superparameterized hindcasts show reduced SST bias in the cold tongue region due to a reduction in surface easterlies despite simulating an excessively strong low‐level jet at 1‐1.5 km elevation. This reflects inadequate vertical mixing of zonal momentum from the absence of convective momentum transport in the superparameterized model. Standard CESM1simulations modified to omit shallow convective momentum transport reproduce the superparameterized low‐level wind bias and associated equatorial SST pattern. Further superparameterized simulations using a three‐dimensional cloud resolving model capable of producing realistic momentum transport simulate a cold tongue similar to the default CESM1. These findings imply convective momentum fluxes may be an underappreciated mechanism for controlling the strength of the equatorial cold tongue. Despite the sensitivity of equatorial SST to these changes in convective parameterization, the east Pacific double‐Intertropical Convergence Zone rainfall bias persists in all simulations presented in this study.
Variability of Bed Load Transport During Six Summers of Continuous Measurements in Two Austrian Mountain Streams (Fischbach and Ruetz)
Authors: Rickenmann Dieter
Published: December 2017

Previous measurements of bed load transport in gravel bed streams revealed a large temporal and spatial variability of bed load transport rates. Using an impact plate geophone system, continuous bed load transport measurements were made during 6 years in two mountain streams in Austria. The two streams have a snow‐melt and glacier‐melt dominated hydrologic regime resulting in frequent transport activity during the summer half year. Periods of days to weeks were identified which are associated with approximately constant Shields values that indicate quasi‐stable bed conditions. Between these stable periods, the position of the bed load transport function varied while its steepness remained approximately constant. For integration time scales of several hours to 1 day, the fluctuations in bed load transport decreased and the correlation between bed load transport and water discharge increased. For integration times of about 70–100 days, bed load transport is determined by discharge or shear stress to within a factor of about 2, relative to the 6 year mean level. Bed load texture increased with increasing mean flow strength and mean transport intensity. Weak and predominantly clockwise daily hysteresis of bed load transport was found for the first half of the summer period.
Interactions Between Stratigraphy and Interfacial Properties on Flow and Trapping in Geologic Carbon Storage
Authors: Liang Bo , Clarens Andres F.
Published: December 2017

Gas leakage from geologic carbon storage sites could undermine the long‐term goal of reducing emissions to the atmosphere and negatively impact groundwater resources. Despite this, there remain uncertainties associated with the transport processes that would govern this leakage. These stem from the complex interaction between governing forces (e.g., gravitational, viscous, and capillary), the heterogeneous nature of the porous media, and the characteristic length scales of these leakage events, all of which impact the CO2 fluid flow processes. Here we assessed how sub‐basin‐scale horizons in porous media could impact the migration and trapping of a CO2 plume. A high‐pressure column packed with two layers of sand with different properties (e.g., grain size and wettability) was used to create a low‐contrast stratigraphic horizon. CO2 in supercritical or liquid phase was injected into the bottom of the column under various conditions (e.g., temperature, pressure, and capillary number) and the transport of the resulting plume was recorded using electrical resistivity. The results show that CO2 trapping was most strongly impacted by shifting the wettability balance to mixed‐wet conditions, particularly for residual saturation. A 16% increase in the cosine of the contact angle for a mixed‐wet sand resulted in nearly twice as much residual trapping. Permeability contrast, pressure, and temperature also impacted the residual saturation but to a lesser extent. Flow rate affected the dynamics of saturation profile development, but the effect is transient, suggesting that the other effects observed here could apply to a broad range of leakage conditions.
Adaptive Computational Methods for Parabolic Problems
Authors: Eriksson Kenneth , Johnson Claes , Logg A.
Published: December 2017

We present a unified methodology for the computational solution of parabolic systems of differential equations with adaptive selection of discretization in space and time, based ona posteriorierror estimates involving residuals of computed solutions and stability factors/weights, obtained by solving an associated linearized dual problem. We define parabolicity as boundedness in time (up to logarithmic factors) of a certain strong stability factor measuring theL1(L2)‐norm in time–space of the time derivative of the dual solution withL2‐normalized initial data.
Time‐Dependent Problems with the Boundary Integral Equation Method
Authors: Costabel Martin , Sayas Francisco‐Javier
Published: December 2017

Time‐dependent problems that are modeled by initial‐boundary value problems for parabolic or hyperbolic partial differential equations can be treated with the boundary integral equation (BIE) method. The ideal situation is when the right‐hand side in the partial differential equation and the initial conditions vanish, the data are given only on the boundary of the domain, the equation is linear with constant coefficients, and the domain does not depend on time. In this situation, the transformation of the problem to a BIE follows the same well‐known lines as for the case of stationary or time‐harmonic problems modeled by elliptic boundary value problems. The same main advantages of the reduction to the boundary prevail: reduction of the dimension by one, and reduction of an unbounded exterior domain to a bounded boundary.

There are, however, specific difficulties due to the additional time dimension. Apart from the practical problems of increased complexity related to the higher dimension, there can appear new stability problems. In the stationary case, one often has unconditional stability for reasonable approximation methods, and this stability is closely related to variational formulations based on the ellipticity of the underlying boundary value problem. In the time‐dependent case, instabilities have been observed in practice, but due to the absence of ellipticity, the stability analysis is more difficult and fewer theoretical results are available.

In this chapter, the mathematical principles governing the construction of BIE methods for time‐dependent problems are presented. We describe some of the main numerical algorithms that are used in practice and have been analyzed in the mathematical literature.
Solids and Structures: Introduction and Survey
Authors: de Borst René
Published: December 2017

Volume 2 “Solids and Structures” is concerned with the numerical analysis of solids and structures in the widest possible sense. Utilizing the basic methods outlined in Volume 1 “Fundamentals”, a comprehensive picture is first given of numerical methods for solids and structures in the linear regime. Next, a wide variety of nonlinear theories are discussed, encompassing structural stability problems as well as instabilities that stem from the properties of the constituent materials. The volume also contains chapters that address computational problems that are specific to particular materials such as concrete, soils, composites, and biomaterials, and to forming processes.

Problems in which interaction between fluids and solids plays a role are covered next, for example, multiphase media, fluid–structure interaction, and structural acoustics. Other important topics that are treated include stochastic finite elements, parameter identification, model reduction, optimization problems, contact, explicit finite element methods for large deformation problems, the analysis of structural problems using boundary element methods, and large rotations.
Models and Finite Elements for Thin‐Walled Structures
Authors: Bischoff Manfred , Ramm E. , Irslinger J.
Published: December 2017

This chapter is a revised, updated, and extended version of the chapter with the same title in the first issue of the “Encyclopedia of Computational Mechanics.” It provides an overview of modeling and discretization aspects in finite element analysis of thin‐walled structures. Shell formulations based on derivation from three‐dimensional continuum mechanics, the direct approach, and the degenerated solid concept are compared, highlighting conditions for their equivalence.

Rather than individually describing the innumerable contributions to theories and finite element formulations for plates and shells, the essential assumptions in modeling and discretization, along with their consequences, are discussed. It is hoped that this approach comprises a good amount of the existing literature by including most concepts in a generic format.

The contribution focuses on nonlinear finite element formulations for large displacements and rotations in the context of elastostatics, including some remarks on stability. Problems involving material nonlinearities and dynamics are other important topics, but these are outside the scope of the present chapter.
Buckling
Authors: Riks Eduard
Published: December 2017

Although the first known solution of a buckling problem was given by the outstanding Swiss ‘natural philosopher’ Leonhard Euler (1744), buckling theory as an engineering subject is an outgrowth of a development that was established during the last century. The overview of the present knowledge regarding the computational analysis of buckling problems is here given in the context of the theory's most important historical developments.
Computational Structural Dynamics
Authors: Hulbert Gregory M.
Published: December 2017

This chapter presents an overview and a state‐of‐the art compilation of time integration methods for solving problems of dynamics, with a particular focus on developments that have occurred during the past 25 years. Various classifications of time integration algorithms are provided that assist the reader in understanding the many different types of numerical methods available for solving time‐dependent problems. Time integration algorithms for linear structural dynamics are reviewed thoroughly, from classical Newmark‐type schemes, to recent developments in time finite element‐based approaches. The distinction between linear and nonlinear dynamics is articulated and numerical methods developed for direct application towards solving nonlinear dynamics probems are presented. The chapter concludes with guidelines towards selecting an appropriate time integration method, along with guidelines towards choosing appropriate time step sizes.
Computational Modeling of Damage and Failures in Composite Laminates
Authors: Reddy J. N. , Robbins D. H.
Published: December 2017

This chapter is intended to provide an overview of issues that are important in the computational modeling of progressive damage and failure in fiber‐reinforced composite laminates. Owing to space limitations, the discussion mainly focuses on those models and methods that have been effectively used by the authors to address this particular class of problems, with references given to other viable models and methods. Topics covered in this chapter are as follows. An introduction and overview of fiber‐reinforced composite laminates, with emphasis on the multiscale nature of this class of materials, is presented in Section 1. Section 2 contains an overview of mathematical models that are commonly used to represent the mechanical behavior of composite laminates. These models constitute a natural hierarchy of models ranging from the simplest two‐dimensional plate model that only represents in‐plane behavior to a fully three‐dimensional layerwise model that includes discrete layer transverse shear and transverse normal effects. In Section 3, an overview of damage and failure models that have been used for composite laminates is presented. Discussion of the coupling between the macroscale and the microscale is presented in Section 4. This micro/macro coupling is achieved through the processes ofhomogenizationandlocalization. Homogenization is the process of determining homogeneous anisotropic material properties that effectively represent the average behavior of the heterogeneous fiber/matrix composite material. Localization is the process of determining the microscopic distribution of stress and strain based on a known macroscopic solution. These topics are discussed in the context of both infinitesimal and finite deformation. Finally, Section 5 is devoted to the description of possible approaches for the modeling of progressive damage. In particular, the discussion focuses on the application of continuum damage mechanics to the homogenized material description used for individual composite laminae. This particular methodology is chosen on the basis of its computational practicality coupled with its ability to describe stiffness reduction to a level of accuracy that is sufficient for a large class of problems. The last section, Section 6 (new with this volume), is concerned with the use of simultaneous, multiple laminate models in simulating progressive damage and global collapse of laminates subjected to combined bending and transverse shear deformation.
Dynamic Multilevel Methods and Turbulence
Authors: Dubois Thierry , Jauberteau Francois , Temam Roger M.
Published: December 2017

In this chapter, we describe numerical multilevel methods applied to the Navier–Stokes equations (homogeneous isotropic turbulence and channel flow problem), to the shallow water equations (geophysical problems), and to the renormalization of small eddies. The first difficulties with multilevel methods is to separate the scales. In this work, various cases are considered: the case of spectral methods, the case of finite difference methods, and the case of finite element methods. Then the numerical treatment is adapted to the size of the computed scales. The aim is to obtain new schemes, with better modeling properties and improved numerical stability. The spectral case is studied in detail, and the results of numerical simulations are reported in this case.

Multilevel numerical methods are indispensable for the approximation of phenomena involving a large number of scales, such as turbulence. Although the methods described in this chapter are generally limited to two levels, they can, as explained in the text, be extended to a more important number of levels, thus extending significantly their performances.
Turbulence Direct Numerical Simulation and Large‐Eddy Simulation
Authors: Sagaut Pierre
Published: December 2017

This chapter deals with direct numerical simulation and large‐eddy simulation (LES) of turbulent flows, which are two techniques for the unsteady three‐dimensional simulation of turbulent motion. For the sake of clarity and brevity, the present framework is restricted to Newtonian, single‐phase, single‐species fluids. Both compressible and incompressible cases are considered. Numerical requirements for both these approaches are discussed, including grid resolution and control of numerical errors. The specific problem of compressible flows with shocks is detailed. The problem of the definition of the filtering procedure and subgrid models for the LES approach is presented, and the main theoretical and practical solutions are given. The difficult question of the definition of boundary conditions is also considered, with emphasis on turbulent inflow conditions and wall stress models. The last section is devoted to the presentation of the evolution of the application of these two techniques.
Retrograde interferon‐gamma signaling induces major histocompatibility class I expression in human‐induced pluripotent stem cell‐derived neurons
Authors: Clarkson Benjamin D. S. , Patel Misha S. , LaFrance‐Corey Reghann G. , Howe Charles L.
Published: December 2017

Objective

Injury‐associated axon‐intrinsic signals are thought to underlie pathogenesis and progression in many neuroinflammatory and neurodegenerative diseases, including multiple sclerosis (MS). Retrograde interferon gamma (IFNγ) signals are known to induce expression of major histocompatibility class I (MHC I) genes in murine axons, thereby increasing the susceptibility of these axons to attack by antigen‐specific CD8+ T cells. We sought to determine whether the same is true in human neurons.

Methods

A novel microisolation chamber design was used to physically isolate and manipulate axons from human skin fibroblast‐derived induced pluripotent stem cell (iPSC)‐derived neuron‐enriched neural aggregates. Fluorescent retrobeads were used to assess the fraction of neurons with projections to the distal chamber. Axons were treated with IFNγ for 72 h and expression of MHC class I and antigen presentation genes were evaluated by RT‐PCR and immunofluorescence.

Results

Human iPSC‐derived neural stem cells maintained as 3D aggregate cultures in the cell body chamber of polymer microisolation chambers extended dense axonal projections into the fluidically isolated distal chamber. Treatment of these axons with IFNγ resulted in upregulation of MHC class I and antigen processing genes in the neuron cell bodies. IFNγ‐induced MHC class I molecules were also anterogradely transported into the distal axon.

Interpretation

These results provide conclusive evidence that human axons are competent to express MHC class I molecules, suggesting that inflammatory factors enriched in demyelinated lesions may render axons vulnerable to attack by autoreactive CD8+ T cells in patients with MS. Future work will be aimed at identifying pathogenic anti‐axonal T cells in these patients.
Enzymatically Produced miR34a Nanoparticles for Enhanced Antiproliferation Activity
Authors: Kim Hyejin , Lee Eunju , Kang Yoon Young , Song Jihyun , Mok Hyejung , Lee Jong Bum
Published: December 2017

Among a range of functional forms of RNA, microRNAs (miRNAs) have held a great promise for their natural ability to influence cellular behavior by regulating gene expression. In particular, it is revealed that miR34a has a function as a tumor suppressor by regulating silent information regulator 1 expression, causing antiproliferation of tumor. To utilize functional miR34a as an effective cancer therapeutics, an enzymatic approach to synthesize miR34a nanoparticles is adapted. The enzymatically self‐assembled miR34a nanoparticles have a high cargo capacity and a suitable size for cellular uptake. Indeed, the miR34a nanoparticles are delivered successfully to PC3 cells, human prostate cancer cells, and suppress proliferation and migration of those cells. These results suggest that the enzymatically produced miR34a nanoparticles can function as an effective tumor suppressor. Furthermore, it is expected that the enzymatic synthesis of miRNA nanoparticles can be adapted universally for delivery of other functional miRNAs as well.
Periosteum Extracellular‐Matrix‐Mediated Acellular Mineralization during Bone Formation
Authors: Lin Xianfeng , Zhao Chenchen , Zhu Peizhi , Chen Jiaxin , Yu Huaguang , Cai Yin , Zhang Qi , Qin An , Fan Shunwu
Published: December 2017

Cell‐mediated mineralization is essential for bone formation and regeneration. In this study, it is proven that extracellular matrix (ECM) of decellularized periosteum can play an initiative and independent role in bone‐like apatite formation. Using decellularized periosteum scaffold, it is revealed that ECM scaffold itself can promote critical bone defect regeneration and nude mouse ectopic ossification. The natural collagen matrix of decellularized periosteum can serve as a 3D structural template for Ca–P nuclei initiation, controlling the size and orientation of bone‐like mineral crystals. The naturally cross‐linked and highly ordered 3D fibrillar network of decellularized periosteum not only provides a model for mimicking mineralization in vitro and in vivo to elucidate the important functions of ECM in bone formation and regeneration, but also can be a promising biomaterial for bone tissue engineering and clinical application.
Cytokine Profiling of Primary Human Macrophages Exposed to Endotoxin‐Free Graphene Oxide: Size‐Independent NLRP3 Inflammasome Activation
Authors: Mukherjee Sourav P. , Kostarelos Kostas , Fadeel Bengt
Published: December 2017

Graphene‐based materials including graphene oxide (GO) are envisioned for a variety of biomedical applications. However, there are conflicting results concerning the biocompatibility of these materials. Here, a question is raised whether GO with small or large lateral dimensions triggers cytotoxicity and/or cytokine responses in primary human monocyte‐derived macrophages. GO sheets produced under sterile conditions by a modified Hummers' method are found to be taken up by macrophages without signs of cytotoxicity. Then, multiplex arrays are used for profiling of proinflammatory and anti‐inflammatory responses. Notably, GO suppresses the lipopolysaccharide (LPS)‐triggered induction of several chemokines and cytokines, including the anti‐inflammatory cytokine, interleukin‐10 (IL‐10). No production of proinflammatory TNF‐αis observed. However, GO elicits caspase‐dependent IL‐1βexpression, a hallmark of inflammasome activation, in LPS‐primed macrophages. Furthermore, GO‐triggered IL‐1 βproduction requires NADPH oxidase‐generated reactive oxygen species and cellular uptake of GO and is accompanied by cathepsin B release and K+ efflux. Using THP‐1 knockdown cells, a role for the inflammasome sensor, NLRP3, the adaptor protein, ASC, and caspase‐1 for GO‐induced IL‐1βsecretion is demonstrated. Finally, these studies show that inflammasome activation is independent of the lateral dimensions of the GO sheets. These studies provide novel insights regarding the immunomodulatory properties of endotoxin‐free GO.
A Black Phosphorus Carbide Infrared Phototransistor
Authors: Tan Wee Chong , Huang Li , Ng Rui Jie , Wang Lin , Hasan Dihan Md. Nuruddin , Duffin Thorin Jake , Kumar Karuppannan Senthil , Nijhuis Christian A. , Lee Chengkuo , Ang Kah‐Wee
Published: December 2017

Photodetectors with broadband detection capability are desirable for sensing applications in the coming age of the internet‐of‐things. Although 2D layered materials (2DMs) have been actively pursued due to their unique optical properties, by far only graphene and black arsenic phosphorus have the wide absorption spectrum that covers most molecular vibrational fingerprints. However, their reported responsivity and response time are falling short of the requirements needed for enabling simultaneous weak‐signal and high‐speed detections. Here, a novel 2DM, black phosphorous carbide (b‐PC) with a wide absorption spectrum up to 8000 nm is synthesized and a b‐PC phototransistor with a tunable responsivity and response time at an excitation wavelength of 2004 nm is demonstrated. The b‐PC phototransistor achieves a peak responsivity of 2163 A W−1 and a shot noise equivalent power of 1.3 fW Hz−1/2 at 2004 nm. In addition, it is shown that a response time of 0.7 ns is tunable by the gating effect, which renders it versatile for high‐speed applications. Under the same signal strength (i.e., excitation power), its performance in responsivity and detectivity in room temperature condition is currently ahead of recent top‐performing photodetectors based on 2DMs that operate with a small bias voltage of 0.2 V.
Recent Progress in Porous Graphene and Reduced Graphene Oxide‐Based Nanomaterials for Electrochemical Energy Storage Devices
Authors: Hooch Antink Wytse , Choi Yejung , Seong Kwang‐dong , Kim Jong Min , Piao Yuanzhe
Published: December 2017

Graphene‐based nanocomposites are characterized by high mechanical strength, excellent electrical conductivity, and outstanding thermal and chemical stability. Additionally, the combination of versatile functionalization chemistry and simplicity of large‐scale synthesis makes graphene ideal for electrode materials for energy storage devices. To improve the electrochemical performance even further, recent research has focused on the preparation of porous graphene structures, either by creating holes in the graphene sheets or by assembling them into a 3D porous framework. Porous graphene and reduced graphene oxide allow for rapid ion diffusion and display high real surface area. In this review paper, the conventional methods for the preparation of porous graphene are summarized and recent progress in porous graphene‐based nanomaterials for electrochemical energy storage devices is discussed.
The social cost of the Black Saturday bushfires
Authors: Ambrey Christopher L. , Fleming Christopher M. , Manning Matthew
Published: December 2017

The Intergovernmental Panel on Climate Change have predicted with high confidence that the risk of bushfires will increase in the future. As this risk increases, so too does the need for appropriate policy responses. In developing these responses, costs need to be weighed against benefits. To fully appreciate the benefits of bushfire risk mitigation policies and strengthen the development of social policies around such events, it is necessary to include the psychological cost of experiencing these events. In this study, we employ the ‘life satisfaction approach’ to place a monetary estimate on the cost of Australia's Black Saturday bushfires (Australia's worst bushfires on record). Results reveal that the bushfires significantly reduce self‐reported levels of life satisfaction, with an implied willingness‐to‐pay of AUD 2,991 in terms of annual household income, or AUD 1,039 per capita, to reduce by one percent the extent to which an individual's immediate local area was affected by the Black Saturday bushfires. In doing so, we identify an apparent gap between current levels of expenditure on bushfire response and mitigation, and that amount which (with the inclusion of associated social benefits) would be welfare maximising.
Synthesis of Difluoromethylthioesters from Aldehydes
Authors: Guo Shi‐Huan , Zhang Xing‐Long , Pan Gao‐Fei , Zhu Xue‐Qing , Gao Ya‐Ru , Wang Yong‐Qiang
Published: December 2017

Difluoromethylthioester compounds are yet another important kind of organofluorine compound and are reported here for the first time. They can be efficiently synthesized from various aldehydes. The synthetic method features mild reaction conditions, good tolerance of functional groups, broad substrate scope, and importantly, no metal is involved in the reaction. The approach has the potential to become an important tool for the late‐stage functionalization of advanced synthetic intermediates, and should have many applications in medicinal chemistry.
Core–Shell Structuring of Pure Metallic Aerogels towards Highly Efficient Platinum Utilization for the Oxygen Reduction Reaction
Authors: Cai Bin , Hübner René , Sasaki Kotaro , Zhang Yuanzhe , Su Dong , Ziegler Christoph , Vukmirovic Miomir B. , Rellinghaus Bernd , Adzic Radoslav R. , Eychmüller Alexander
Published: December 2017

The development of core–shell structures remains a fundamental challenge for pure metallic aerogels. Here we report the synthesis of PdxAu‐Pt core–shell aerogels composed of an ultrathin Pt shell and a composition‐tunable PdxAu alloy core. The universality of this strategy ensures the extension of core compositions to Pd transition‐metal alloys. The core–shell aerogels exhibited largely improved Pt utilization efficiencies for the oxygen reduction reaction and their activities show a volcano‐type relationship as a function of the lattice parameter of the core substrate. The maximum mass and specific activities are 5.25 A mgPt−1 and 2.53 mA cm−2, which are 18.7 and 4.1 times higher than those of Pt/C, respectively, demonstrating the superiority of the core–shell metallic aerogels. The proposed core‐based activity descriptor provides a new possible strategy for the design of future core–shell electrocatalysts.
Magnetically separable g‐C3N4 hybrid nanocomposite: Highly efficient and eco‐friendly recyclable catalyst for one‐pot synthesis of α‐aminonitriles
Authors: Azizi Najmedin , Farhadi Elham
Published: December 2017

A magnetically separable graphitic carbon nitride nanocomposite (Fe3O4/g‐C3N4) as a catalyst for the three‐component condensation reactions of carbonyl compounds, amines and trimethylsilylcyanide was thoroughly investigated. The reaction of these three components was found to be efficient, economical and green and took place in the presence of a catalytic amount of the magnetically separable catalyst to yield the corresponding α‐aminonitriles in good to excellent yields. The prepared nanocomposite was characterized using scanning electron microscopy and energy‐dispersive X‐ray and Fourier transform infrared spectroscopies. The nanocomposite was also found to be reusable could be recovered easily and reused several times without distinct deterioration in its catalytic activity.