bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting the sensitivity of populations from individual exposure to chemicals: The role of ecological interactions
Authors: Gabsi Faten , Schäffer Andreas , Preuss Thomas G. 
Published: October 2013

Abstract

Population responses to chemical stress exposure are influenced by nonchemical, environmental processes such as species interactions. A realistic quantification of chemical toxicity to populations calls for the use of methodologies that integrate these multiple stress effects. The authors used an individual-based model for Daphnia magna as a virtual laboratory to determine the influence of ecological interactions on population sensitivity to chemicals with different modes of action on individuals. In the model, hypothetical chemical toxicity targeted different vital individual-level processes: reproduction, survival, feeding rate, or somatic growth rate. As for species interactions, predatory and competition effects on daphnid populations were implemented following a worst-case approach. The population abundance was simulated at different food levels and exposure scenarios, assuming exposure to chemical stress solely or in combination with either competition or predation. The chemical always targeted one vital endpoint. Equal toxicity-inhibition levels differently affected the population abundance with and without species interactions. In addition, population responses to chemicals were highly sensitive to the environmental stressor (predator or competitor) and to the food level. Results show that population resilience cannot be attributed to chemical stress only. Accounting for the relevant ecological interactions would reduce uncertainties when extrapolating effects of chemicals from individuals to the population level. Validated population models should be used for a more realistic risk assessment of chemicals. Environ Toxicol Chem 2014;33:1449–1457. © 2014 SETAC
Influence of carbon nanotubes with preloaded and coexisting dissolved organic matter on the bioaccumulation of polycyclic aromatic hydrocarbons to Chironomus plumosus larvae in sediment
Authors: Shen Mohai , Xia Xinghui , Zhai Yawei , Zhang Xiaotian , Zhao Xiuli , Zhang Pu 
Published: October 2013

Abstract

The ubiquity of dissolved organic matter (DOM) in an aqueous environment may have influence on the carbonaceous material's impact on the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) to benthonic organisms in contaminated sediment. In the present study, 1 multiwalled carbon nanotube (MWNT); 2 types of DOM (fulvic acid and tannic acid), and 2 PAHs (pyrene and chrysene) were selected to study the influence of MWNT with preloaded and coexisting DOM on the bioaccumulation of PAHs to Chironomus plumosus larvae in sediment. Moreover, the freely dissolved concentrations of PAHs were measured to explore the influence mechanisms. The results showed that despite the presence or absence of preloaded or coexisting DOM, the presence of 1% MWNT in sediments suppressed the biota-sediment accumulation factor (BSAF) and elevated the water-based bioaccumulation factor (BAF) of PAHs. However, the BSAF and BAF values generally decreased with the increase of 2 forms of both DOM; this was caused by the combined impact of DOM and MWNT on the freely dissolved concentrations of PAHs and the ingestion behavior of benthic organisms. Environ Toxicol Chem 2014;33:182–189. © 2013 SETAC
Metabolomic analysis of soil communities can be used for pollution assessment
Authors: Jones Oliver A.H. , Sdepanian Stephanie , Lofts Steven , Svendsen Claus , Spurgeon David J. , Maguire Mahon L. , Griffin Julian L. 
Published: October 2013

Abstract

Metabolic profiling can be used to assess the changes in biochemical profiles of soil communities living in contaminated sites. The term “community metabolomics” is proposed for the application of metabolomics techniques to the study of the entire community of a soil sample. The authors anticipate the present study to be a starting point for the use of this technique to assess how communities respond to factors such as pollution and climate change. Environ Toxicol Chem 2014;33:61–64. © 2013 SETAC
On the feasibility of indoor broadband secondary access to 960–1215 MHz aeronautical spectrum
Authors: Obregon Evanny , Sung Ki Won , Zander Jens 
Published: October 2013

ABSTRACTIn this paper, we analyse the feasibility of indoor broadband service provisioning using secondary spectrum access to the 960–1215 MHz band, primarily allocated to the distance measuring equipment (DME) system for aeronautical navigation. We propose a practical secondary sharing scheme customised to the characteristics of the DME. Because the primary system performs a safety‐of‐life functionality, protection from harmful interference becomes extremely critical. The proposed scheme controls aggregate interference by imposing an individual interference threshold on the secondary users. We examine the feasibility of large scale secondary access in terms of the transmission probability of the secondary users that keeps the probability of harmful interference below a given limit. Uncertainties in the estimation of propagation loss and DME location affect the feasibility of the secondary access. Numerical results show that a large number of secondary users are able to operate in adjacent DME channels without harming the primary system even with limited accuracy on the estimation of the propagation loss. Copyright © 2013 John Wiley & Sons, Ltd.
The heterogeneity of inter‐domain Internet application flows: entropic analysis and flow graph modelling
Authors: Yu Ke , Li Frank Y. , Wu Xiaofei , Di Jiaxi 
Published: October 2013

AbstractThe growing popularity of the Internet has triggered the proliferation of various applications, which possess diverse communication patterns and user behaviour. In this paper, the heterogeneous characteristics of Internet applications and traffic are investigated from a complex network and entropic perspective. On the basis of real‐life flow data collected from a public network provided by an Internet service provider, flow graphs are constructed for five types of applications as follows: Web, P2P Download, P2P Stream, Video Stream and Instant Messaging. Three types of entropy measures are introduced to the flow graphs, and the heterogeneity of applications within a 24‐h period is analysed and compared. By using the strict timing information of the flow records, the growth process and the entropy fluctuation of flow graphs are observed. On the basis of the analysis of the flow records, a complex network model is developed for the flow graph growth. Simulation results show that the novel model matches well the flow graphs in terms of both degree distribution and entropy dynamics. Our analysis results and the proposed model shed light on traffic identification and modelling for inter‐domain traffic in today's Internet. Copyright © 2013 John Wiley & Sons, Ltd.
Adaptive resource allocation and decoding strategy for underlay multi‐carrier cooperative cognitive radio systems
Authors: Pischella Mylene , Le Ruyet Didier 
Published: October 2013

ABSTRACTThis paper proposes a resource allocation and decoding strategy at the secondary system for underlay and interweave multi‐carrier cooperative cognitive radio. The objective is to maximise the sum rate of both primary and secondary systems, taking into account the interference threshold constraint and the fact that the primary receiver always considers interference as noise. The decoding method at the secondary receivers is either Successive Interference Cancellation or treating interference as noise, depending on their channel gains. The rationale for this strategy is the extension of the Han–Kobayashi capacity‐achieving strategy on the Gaussian interference channel to the studied cognitive scenario. The proposed resource allocation algorithm is composed of a subcarrier allocation procedure to avoid intercell interference between secondary cells and of an iterative power allocation algorithm that maximises the sum rate on the primary and secondary cells, respectively. The proposed algorithm achieves high data rate improvements for the secondary systems while maintaining a low degradation on the primary system's rate. It also benefits from multi‐user diversity and is robust to the distance variations. Copyright © 2013 John Wiley & Sons, Ltd.
Novel flame‐retardant epoxy based on zinc methylethyl phosphinate
Authors: Liu Xueqing , Liu Jiyan , Sun Shan , Chen Jia , Cai Shaojun 
Published: October 2013

ABSTRACTA novel flame retardant zinc methylethylphosphinate (Zn(MEP)) was used to fill epoxy resins (EPs). The structure of Zn(MEP) was conformed with Fourier transform infrared, hydrogen nuclear magnetic resonance and phosphorus nuclear magnetic resonance, and X‐ray fluorescent and X‐ray diffraction. The flammability, decomposition behavior, and glass transition temperature (Tg) of cured EP/Zn(MEP) were investigated. Zn(MEP) is stable below 406°C. EP containing 20 phr of Zn(MEP) achieves 27.5% of limiting oxygen index and UL‐94 V0 rating. Scanning electron microscopy‐energy‐dispersive X‐ray and Fourier transform infrared spectroscopy investigations show that a condensed char layer with carbon‐rich and phosphorus‐rich components was formed during heating Zn(MEP)/EP, the atomic ratio of P to Zn on the surface of the char is reduced compared with the initial sample. The P‐rich components and lower atomic ratio of P/Zn on the char surface implies that the Zn(MEP) acts in both condensed phase and gas phase. TGA investigation shows that there are interactions between Zn(MEP) and EP when they are copyrolyzed. The interactions lead to a modification in degradation process and promote the char forming. Compared with aluminum diethylphosphinate Zn(MEP) filled EP shows lower limiting oxygen index but higher Tg. In addition, the interactions between polymer and additive are different when aluminum diethylphosphinate instead of Zn(MEP) is added into EP. Copyright © 2013 John Wiley & Sons, Ltd.
Furan resin as a replacement of phenolics: influence of the clay addition on its thermal degradation and fire behaviour
Authors: Rivero Guadalupe , Villanueva Sara , Manfredi Liliana B. 
Published: October 2013

SummaryNanocomposites based on a furan resin and different types of clays were obtained. Their thermal and fire behaviours were compared with traditional phenolic resins, which are known by their excellent flame resistance. Three types of montmorillonite clays were in situ added to the thermosetting matrix. A cone calorimeter and a smoke chamber were used to evaluate the performance of the materials against fire and their smokes generation. Global parameters were calculated for comparison purposes. Fires derived from the furan resin combustion grow faster than the phenolic ones, but they are extinguished more rapidly. This effect is enhanced by the incorporation of inorganic nanofillers. The only addition of any clay causes shorter fires but slightly speeds up the degradation process. A homogeneous nanofiller dispersion was found to be crucial to achieve good fire behaviour. Nevertheless, for materials with similar dispersion, the crosslinking degree of the polymer matrix appears as a secondary factor that determines slighter differences in the performance. Nanocomposites with organomodified clays showed a quite similar fire performance, though the composite containing the clay (Southern Clay Products, Inc., Louisville, Ky, USA) Cloisite®30B showed the best performance taking into account both the fire risk and the smoke evolution and obscuration. Copyright © 2013 John Wiley & Sons, Ltd.
The quest for odorants having salicylate notes
Authors: Gaudin Jean‐Marc 
Published: October 2013

ABSTRACTWe describe the synthesis and sensory characterization of a series of compounds which we anticipated would possess the olfactory notes of salicylates. We explored carba‐analogues, cyclic β‐keto esters and cyclic β‐diketones as salicylate analogues. Applying the simple concept of three‐dimensional structure similarity was very fruitful. Salicylate carba‐analogues and β‐keto esters, especially compounds 5, 7 and 10 for the first series and 27 and 28 for the second series, proved to be the most interesting type of compounds. For example, 1‐(2‐hydroxyphenyl)‐3‐phenyl‐1‐propanone (10), which can be found in nature, is nicely diffusive and has an excellent olfactory profile with an interesting dual floral–animal note. In general, these compounds may offer a first credible alternative to the popular salicylates. Copyright © 2013 John Wiley & Sons, Ltd.
A simple sliding‐mesh interface procedure and its application to the CFD simulation of a tidal‐stream turbine
Authors: McNaughton J. , Afgan I. , Apsley D. D. , Rolfo S. , Stallard T. , Stansby P. K. 
Published: October 2013

SUMMARYAn effective way of using computational fluid dynamics (CFD) to simulate flow about a rotating device—for example, a wind or marine turbine—is to embed a rotating region of cells inside a larger, stationary domain, with a sliding interface between. This paper describes a simple but effective method for implementing this as an internal Dirichlet boundary condition, with interfacial values obtained by interpolation from halo nodes. The method is tested in two finite‐volume codes: one using block‐structured meshes and the other unstructured meshes. Validation is performed for flow around simple, isolated, rotating shapes (cylinder, sphere and cube), comparing, where possible, with experiment and the alternative CFD approach of fixed grid with moving walls. Flow variables are shown to vary smoothly across the sliding interface. Simulations of a tidal‐stream turbine, including both rotor and support, are then performed and compared with towing‐tank experiments. Comparison between CFD and experiment is made for thrust and power coefficients as a function of tip‐speed ratio (TSR) using Reynolds‐averaged Navier–Stokes turbulence models and large‐eddy simulation (LES). Performance of most models is good near the optimal TSR, but simulations underestimate mean thrust and power coefficients in off‐design conditions, with the standard k– ϵ turbulence model performing noticeably worse than shear stress transport k– ω and Reynolds‐stress‐transport closures. LES gave good predictions of mean load coefficients and vital information about wake structures but at substantial computational cost. Grid‐sensitivity studies suggest that Reynolds‐averaged Navier–Stokes models give acceptable predictions of mean power and thrust coefficients on a single device using a mesh of about 4 million cells. Copyright © 2013 John Wiley & Sons, Ltd.
Searching the best equilibrium moisture equation for lettuce seeds using measures of curvature and bias
Authors: Bortolotti Carolina T. , Barrozo Marcos A. S. 
Published: October 2013

AbstractIn the present work, we performed a discrimination analysis of the nonlinear equations used to describe sorption isotherms of the lettuce seeds. The equilibrium data were obtained by the static method using saturated salt solutions. The best model to describe the equilibrium moisture of lettuce seeds was selected using measures of curvature and bias. The obtained results showed that the Copace equation was the best model in terms of nonsignificance for bias and nonlinearity measures.
Hysteresis conditions the vertical position of deep chlorophyll maximum in the temperate ocean
Authors: Navarro Gabriel , Ruiz Javier 
Published: October 2013

AbstractDeep chlorophyll maxima (DCMs) are widespread features of oceans. In temperate regions, DCMs are commonly associated with isopycnal surfaces that frequently move over a wide vertical range. This general association between DCMs and isopycnals remains unexplained by present theories, and we show here that it emerges from the seasonal history of the water column. Analysis of the formation of more than 9000 seasonal DCMs throughout the world's oceans consistently locates the vertical position of spring/summer DCMs in temperate seas at the density of the previous winter mixed layer, independently of this density value and future depth. These results indicate that DCM formation cannot be understood without hysteresis by solely considering the instantaneous response of phytoplankton to vertical gradients in physical and chemical fields. Present theories for DCM formation cannot explain why spring and summer DCMs are systematically found at a density equal to that of the previous mixed layer where a bloom has occurred. Rather than reacting to instantaneous physical forcing, the results indicate that DCMs operate as self‐preserving biological structures that are associated with particular isopycnals because of their capacity to modify the physicochemical environment. Combined with remote sensors to measure salinity and temperature in the surface ocean, this new understanding of DCM dynamics has the potential to improve the quantification of three‐dimensional primary production via satellites. This significant enhancement of the representation of oceanic biological processes can also allow increasingly realistic predictions of future biogeochemical scenarios in a warming ocean.
Gene‐Environment Interactions in Cancer Epidemiology: A National Cancer Institute Think Tank Report
Authors: Hutter Carolyn M. , Mechanic Leah E. , Chatterjee Nilanjan , Kraft Peter , Gillanders Elizabeth M. 
Published: October 2013

ABSTRACTCancer risk is determined by a complex interplay of genetic and environmental factors. Genome‐wide association studies (GWAS) have identified hundreds of common (minor allele frequency [MAF] > 0.05) and less common (0.01 < MAF < 0.05) genetic variants associated with cancer. The marginal effects of most of these variants have been small (odds ratios: 1.1–1.4). There remain unanswered questions on how best to incorporate the joint effects of genes and environment, including gene‐environment (G × E) interactions, into epidemiologic studies of cancer. To help address these questions, and to better inform research priorities and allocation of resources, the National Cancer Institute sponsored a “Gene‐Environment Think Tank” on January 10–11, 2012. The objective of the Think Tank was to facilitate discussions on (1) the state of the science, (2) the goals of G × E interaction studies in cancer epidemiology, and (3) opportunities for developing novel study designs and analysis tools. This report summarizes the Think Tank discussion, with a focus on contemporary approaches to the analysis of G × E interactions. Selecting the appropriate methods requires first identifying the relevant scientific question and rationale, with an important distinction made between analyses aiming to characterize the joint effects of putative or established genetic and environmental factors and analyses aiming to discover novel risk factors or novel interaction effects. Other discussion items include measurement error, statistical power, significance, and replication. Additional designs, exposure assessments, and analytical approaches need to be considered as we move from the current small number of success stories to a fuller understanding of the interplay of genetic and environmental factors.
A Whole‐Genome Simulator Capable of Modeling High‐Order Epistasis for Complex Disease
Authors: Yang Wei , Gu C. Charles 
Published: October 2013

ABSTRACTGenome‐wide association studies (GWAS) have been successful in finding numerous new risk variants for complex diseases, but the results almost exclusively rely on single‐marker scans. Methods that can analyze joint effects of many variants in GWAS data are still being developed and trialed. To evaluate the performance of such methods it is essential to have a GWAS data simulator that can rapidly simulate a large number of samples, and capture key features of real GWAS data such as linkage disequilibrium (LD) among single‐nucleotide polymorphisms (SNPs) and joint effects of multiple loci (multilocus epistasis). In the current study, we combine techniques for specifying high‐order epistasis among risk SNPs with an existing program GWAsimulator [Li and Li, 2008] to achieve rapid whole‐genome simulation with accurate modeling of complex interactions. We considered various approaches to specifying interaction models including the following: departure from product of marginal effects for pairwise interactions, product terms in logistic regression models for low‐order interactions, and penetrance tables conforming to marginal effect constraints for high‐order interactions or prescribing known biological interactions. Methods for conversion among different model specifications are developed using penetrance table as the fundamental characterization of disease models. The new program, called simGWA, is capable of efficiently generating large samples of GWAS data with high precision. We show that data simulated by simGWA are faithful to template LD structures, and conform to prespecified diseases models with (or without) interactions.
Adjusting for Population Stratification in a Fine Scale With Principal Components and Sequencing Data
Authors: Zhang Yiwei , Shen Xiaotong , Pan Wei 
Published: October 2013

ABSTRACTPopulation stratification is of primary interest in genetic studies to infer human evolution history and to avoid spurious findings in association testing. Although it is well studied with high‐density single nucleotide polymorphisms (SNPs) in genome‐wide association studies (GWASs), next‐generation sequencing brings both new opportunities and challenges to uncovering population structures in finer scales. Several recent studies have noticed different confounding effects from variants of different minor allele frequencies (MAFs). In this paper, using a low‐coverage sequencing dataset from the 1000 Genomes Project, we compared a popular method, principal component analysis (PCA), with a recently proposed spectral clustering technique, called spectral dimensional reduction (SDR), in detecting and adjusting for population stratification at the level of ethnic subgroups. We investigated the varying performance of adjusting for population stratification with different types and sets of variants when testing on different types of variants. One main conclusion is that principal components based on all variants or common variants were generally most effective in controlling inflations caused by population stratification; in particular, contrary to many speculations on the effectiveness of rare variants, we did not find much added value with the use of only rare variants. In addition, SDR was confirmed to be more robust than PCA, especially when applied to rare variants.