bluuebunny/crossref_metadata_2025_split huggingface dataset:
Roles of mating behavioural interactions and life history traits in the competition between alien and indigenous whiteflies
Authors: Wang P. , Crowder D.W. , Liu S.-S. 
Published: March 2012

AbstractInterference competition between closely related alien and indigenous species often influences the outcome of biological invasions. The whitefly Bemisia tabaci species complex contains ≥28 putative species and two of them, Mediterranean (MED, formally referred to as the ‘Q biotype’) and Middle East-Asia Minor 1 (MEAM1, formally referred to as the ‘B biotype’), have recently spread to much of the world. In many invaded regions, these species have displaced closely related indigenous whitefly species. In this study, we integrated laboratory population experiments, behavioural observations and simulation modelling to investigate the capacity of MED to displace Asia II 1 (AII1, formally referred to as the ‘ZHJ2 biotype’), an indigenous whitefly widely distributed in Asia. Our results show that intensive mating interactions occur between MED and AII1, leading to reduced fecundity and progeny female ratio in AII1, as well as an increase in progeny female ratio in MED. In turn, our population cage experiments demonstrated that MED has the capacity to displace AII1 in a few generations. Using simulation models, we then show that both asymmetric mating interactions and differences in life history traits between the two species contribute substantially to the process of displacement. These findings would help explain the displacement of AII1 by MED in the field and, together with earlier studies on mating interactions between other species of the B. tabaci complex, indicate the widespread significance of asymmetric mating interactions in whitefly species exclusions.
UNDERSTANDING THE ASSOCIATION BETWEEN MATERNAL EDUCATION AND USE OF HEALTH SERVICES IN GHANA: EXPLORING THE ROLE OF HEALTH KNOWLEDGE
Authors: SMITH GREENAWAY EMILY , LEON JUAN , BAKER DAVID P. 
Published: March 2012

SummaryThis paper examines the role of health knowledge in the association between mothers' education and use of maternal and child health services in Ghana. The study uses data from a nationally representative sample of female respondents to the 2008 Ghana Demographic and Health Survey. Ordered probit regression models evaluate whether women's health knowledge helps to explain use of three specific maternal and child health services: antenatal care, giving birth with the supervision of a trained professional and complete child vaccination. The analyses reveal that mothers' years of formal education are strongly associated with health knowledge; health knowledge helps explain the association between maternal education and use of health services; and, net of a set of stringent demographic and socioeconomic controls, mothers' health knowledge is a key factor associated with use of health services.
Effects of environmental policy on consumption: lessons from the Chinese plastic bag regulation
Authors: He Haoran 
Published: March 2012

AbstractTo reduce plastic bag litter, China introduced a nationwide regulation requiring all retailers to charge for plastic shopping bags on 1 June 2008. By using the policy implementation as a natural experiment and collecting individual-level data before and after the implementation, we investigate the impacts of the regulation on consumers’ bag use. We find that the regulation implementation caused a 49 per cent reduction in the use of new bags. Besides regulation enforcement, consumers’ attitude toward the regulation and some consumers’ socioeconomic characteristics also affected bag consumption. However, the regulation effects differ largely among consumer groups and among regions and shopping occasions.
Environmental policy in a linear city model of product differentiation
Authors: Espínola-Arredondo Ana , Zhao Huan 
Published: March 2012

AbstractThis paper analyzes how a tax/subsidy policy affects consumers' behavior when choosing between green (pollution-free goods) and conventional products, and its effects on welfare when a proportion of consumers have strong preferences for green goods. We analyze a Hotelling's linear city model where final products by two firms are symmetric in all dimensions except for the externality their production process generates. Our efficiency comparisons suggest that, under a setting of horizontal product differentiation, an environmental regulation (either on polluting firms or consumers buying their products) yields higher social welfare than the absence of policy. Moreover, the proportion of consumers who prefer green products affects the welfare gains from a subsidy or tax policy.
Period doubling in magnetospheric convection cycle
Authors: Liu W. William 
Published: March 2012

A gedanken investigation is performed on magnetospheric complexity. In an attempt to separate complexities due to external (solar wind) and internal (magnetospheric) dynamics, we hold the solar wind condition constant and investigate how the open flux in the magnetosphere changes from one convection cycle to the next. The change of open flux is related to the time integral of the tail electric field. This field, in turn, is proportional to the product of the normal (x) and tangential (z) components of the tail magnetic field. As the magnetosphere evolves, the magnetic components typically vary in opposite directions. We show that this competition leads to a magnetic flux cycle described by the classical logistic equation xn+1 = r(1 − xn)xn, where x is a linear function of open flux, the much researched route to chaos through period‐doubling. The result could provide a possible explanation of the steady magnetospheric convection, sawtooth events, and other observed manifestations of nonlinearity.
Complexity of the Mw 6.3 2009 L'Aquila (central Italy) earthquake: 1. Multiple finite‐extent source inversion
Authors: Gallovič F. , Zahradník J. 
Published: March 2012

Strong ground motion recordings of the Mw 6.3 2009 L'Aquila earthquake are analyzed by a newly proposed slip inversion technique. The source model consists of Multiple Finite‐Extent (MuFEx) subsources. The slip amplitude, rupture velocity, rake and risetime are assumed constant within each subsource. The size and location of the MuFEx subsources have to be inferred independently from other methods, preferably those free of strong constraints (such as constant rupture velocity over the whole fault, etc); here we use two published approaches satisfying such requirement: the truncated singular value decomposition and the iterative multiple‐point source deconvolution. Each MuFEx subsource is characterized by an individual set of trial nucleation points, rupture velocities and nucleation times, which are grid‐searched. For each combination of these parameters, the subsources' slip is determined by the least squares approach. This procedure thus provides not only the best fitting model, but also a whole range of acceptable models, allowing for the uncertainty analysis. The method is demonstrated on three synthetic tests. When applied to the L'Aquila data, both the best fitting model and the uncertainty analysis suggest that the event consisted of two major episodes, one with the rupture propagating immediately after the nucleation in the updip direction, the other being delayed by 3–4 s with dominant propagation toward the SE along the deeper part of the fault. The retrieved complexity of the rupture propagation warns against attempts to stabilize inversions by the use of a constant rupture velocity over the whole fault.
Seasonal variability of upper ocean heat content in Drake Passage
Authors: Stephenson Gordon R. , Gille Sarah T. , Sprintall Janet 
Published: March 2012

Mixed‐layer depth (MLD) is often used in a mixed‐layer heat budget to relate air‐sea exchange to changes in the near‐surface ocean temperature. In this study, reanalysis heat flux products and profiles from a 15 year time series of high‐resolution, near‐repeat expendable bathythermograph/expendable conductivity‐temperature‐depth (XBT/XCTD) sampling in Drake Passage are used to examine the nature of MLD variations and their impact on a first‐order, one‐dimensional heat budget for the upper ocean in the regions north and south of the Polar Front. Results show that temperature and density criteria yield different MLD estimates, and that these estimates can be sensitive to the choice of threshold. The difficulty of defining MLD in low‐stratification regions, the large amplitude of wintertime MLD (up to 700 m in Drake Passage), and the natural small‐scale variability of the upper ocean result in considerable cast‐to‐cast variability in MLD, with changes of up to 200 m over 10 km horizontal distance. In contrast, the heat content over a fixed‐depth interval of the upper ocean shows greater cast‐to‐cast stability and clearly measures the ocean response to surface heat fluxes. In particular, an annual cycle in upper ocean heat content is in good agreement with the annual cycle in heat flux forcing, which explains ∼24% of the variance in heat content above 400 m depth north of the Polar Front and ∼63% of the variance in heat content south of the Polar Front.
Vibrational relaxation of CO2(ν2) by O(3P) in the 142–490 K temperature range
Authors: Castle Karen J. , Black Labe A. , Simione Michael W. , Dodd James A. 
Published: March 2012

Laboratory measurements of the quenching of CO2(ν2) by O atoms are presented over the 142–490 K temperature range relevant to the 75–120 km altitude region of the terrestrial atmosphere. The primary cooling mechanism in this region occurs when CO2 is efficiently excited through collisions with ambient O atoms, populating the bending vibrational (ν2) modes. A significant fraction of the vibrationally excited CO2 relaxes through spontaneous 15‐μm emission that escapes into space, thereby removing kinetic energy from this region of the atmosphere and generating a local cooling effect. The rate coefficient for the vibrational relaxation of CO2(ν2) by O atoms, kO(ν2), is measured using transient diode laser absorption spectroscopy. A slight negative temperature dependence is observed for kO(ν2), with values ranging from 2.7 (±0.4) × 10−12 cm3 s−1 at 142 K to 1.3 (±0.2) × 10−12 cm3 s−1 at 490 K.
Metagenomic and metaproteomic insights into bacterial communities in leaf-cutter ant fungus gardens
Authors: Aylward Frank O , Burnum Kristin E , Scott Jarrod J , Suen Garret , Tringe Susannah G , Adams Sandra M , Barry Kerrie W , Nicora Carrie D , Piehowski Paul D , Purvine Samuel O , Starrett Gabriel J , Goodwin Lynne A , Smith Richard D , Lipton Mary S , Currie Cameron R 
Published: March 2012

Abstract
Herbivores gain access to nutrients stored in plant biomass largely by harnessing the metabolic activities of microbes. Leaf-cutter ants of the genus Atta are a hallmark example; these dominant neotropical herbivores cultivate symbiotic fungus gardens on large quantities of fresh plant forage. As the external digestive system of the ants, fungus gardens facilitate the production and sustenance of millions of workers. Using metagenomic and metaproteomic techniques, we characterize the bacterial diversity and physiological potential of fungus gardens from two species of Atta. Our analysis of over 1.2 Gbp of community metagenomic sequence and three 16S pyrotag libraries reveals that in addition to harboring the dominant fungal crop, these ecosystems contain abundant populations of Enterobacteriaceae, including the genera Enterobacter, Pantoea, Klebsiella, Citrobacter and Escherichia. We show that these bacterial communities possess genes associated with lignocellulose degradation and diverse biosynthetic pathways, suggesting that they play a role in nutrient cycling by converting the nitrogen-poor forage of the ants into B-vitamins, amino acids and other cellular components. Our metaproteomic analysis confirms that bacterial glycosyl hydrolases and proteins with putative biosynthetic functions are produced in both field-collected and laboratory-reared colonies. These results are consistent with the hypothesis that fungus gardens are specialized fungus–bacteria communities that convert plant material into energy for their ant hosts. Together with recent investigations into the microbial symbionts of vertebrates, our work underscores the importance of microbial communities in the ecology and evolution of herbivorous metazoans.
Molecular dynamics and kinetic study of carbon coagulation in the release wave of detonation products
Authors: Chevrot Guillaume , Sollier Arnaud , Pineau Nicolas 
Published: March 2012

We present a combined molecular dynamics and kinetic study of a carbon cluster aggregation process in thermodynamic conditions relevant for the detonation products of oxygen deficient explosives. Molecular dynamics simulations with the LCBOPII potential under gigapascal pressure and high temperatures indicate that (i) the cluster motion in the detonation gas is compatible with Brownian diffusion and (ii) the coalescence probability is 100% for two clusters entering the interaction cutoff distance. We used these results for a subsequent kinetic study with the Smoluchowski model, with realistic models applied for the physical parameters such as viscosity and cluster size. We found that purely aggregational kinetics yield too fast clustering, with moderate influence of the model parameters. In agreement with previous studies, the introduction of surface reactivity through a simple kinetic model is necessary to approach the clustering time scales suggested by experiments (1000 atoms after 100 ns, 10 000 atoms after 1 μs). However, these models fail to reach all experimental criteria simultaneously and more complex modelling of the surface process seems desirable to go beyond these current limitations.
European athletes dominate performances in Double Iron ultra‐triathlons – A retrospective data analysis from 1985 to 2010
Authors: Rüst Christoph Alexander , Knechtle Beat , Knechtle Patrizia , Lepers Romuald , Rosemann Thomas , Onywera Vincent 
Published: March 2012

AbstractWe investigated the participation and performance trends of ultra‐endurance triathletes from all nationalities competing in a Double Iron ultra‐triathlon (7.6‐km swim, 360‐km cycle and 84.4‐km run) from 1985 to 2010. A total of 1854 athletes participated in 92 Double Iron ultra‐triathlons. The majority of the winners came from Europe with 72 victories, followed by North America with 17 victories. The race time for the European ultra‐triathletes was 1340 (s=95.3) min, decreasing highly significantly (r 2=0.28; P<0.0001) across the years. North American ultra‐triathletes finished the races within 1556 (s=124.5) min; their race time showed no changes across the years (r 2=0.045; P=0.07). The race time for the Europeans was highly significantly faster compared to the North Americans (P<0.0001). Future studies should investigate each country in Europe and North America in order to find the country with the largest participation of athletes and their best performance.
Inactivity‐induced oxidative stress: A central role in age‐related sarcopenia?
Authors: Derbré Frédéric , Gratas‐Delamarche Arlette , Gómez‐Cabrera Mari Carmen , Viña José 
Published: March 2012

AbstractAgeing causes a progressive decline in skeletal muscle mass that may lead to decreased strength and functionality. The term sarcopenia is especially used to characterise this geriatric syndrome. Numerous conditions and behaviours are considered to accelerate the progression of sarcopenia such as chronic diseases, malnutrition and physical inactivity. As people in modern countries are more and more sedentary, the impact of physical inactivity on the prevalence of sarcopenia might be more and more important in the future. In this review, we discuss how reactive oxygen species (ROS) could mediate the effects of lifelong inactivity in the onset and progression of age‐related sarcopenia. Although the cellular mechanisms responsible for muscle ROS production are not necessarily the same, both inactivity and ageing are indeed known to increase basal ROS concentrations in skeletal muscle. New data and literature review are provided showing that chronic ROS overproduction induced by physical inactivity may exacerbate the activation of some redox‐sensitive signalling pathways involved in age‐related sarcopenia. We also address the scientific evidences implicating the role of ROS overproduction in the precocious failure of aged muscles to activate intracellular signalling responses to contractions.
The effects of air travel on performance measures of elite Australian rugby league players
Authors: McGuckin Teneale Alyce , Sinclair Wade Heath , Sealey Rebecca Maree , Bowman Paul 
Published: March 2012

AbstractThe current study explored the effects of short haul air travel within the same country on elite Australian rugby league (RL) players (n=12) during two away and two home games of elite competition. Physiological tests of handgrip strength and leg power were assessed along with psychological tests and perceptions of leg soreness and tiredness on the day before the game (Time 1 and Time 2) and on game day (Time 3). Game statistics of tackles and metres gained were assessed for the games analysed. Significant differences were found for daily analyses of life demands for athletes (DALDA) worse than normal responses at Time 2 (2.50±3.23 vs. 3.50±3.93; P=0.04), Karolinska Sleepiness Scale (KSS) at Time 2 (2.88±1.51 vs. 3.71±1.37; P=0.011) and leg tiredness at Time 3 (3.38±1.66 vs. 2.35±1.70; P=0.004) between home and away games. The analysis of game statistics identified that more metres were gained during home games (83.6±49.1 vs. 63.0±30.1; P=0.02) and more tackles made while playing away (18.4±9.2 vs. 14.3±6.7; P=0.016). The results suggest that short haul air travel without crossing time zones results in symptoms of travel fatigue but does not appear to negatively impact on elite RL players ability to perform strength and power tasks. Different game tactics (attacking vs. defensive) occurred between home and away games however, it is unclear whether travel fatigue or a home advantage (HA) is associated with this finding.
Binding of Autoantibodies to the Core Region of Tissue Transglutaminase Is a Feature of Paediatric Coeliac Disease
Authors: Comerford Ross , Byrne Greg , Feighery Conleth , Kelly Jacinta 
Published: March 2012

ABSTRACTObjectives:Production of autoantibodies to the enzyme tissue transglutaminase (tTG) is a hallmark of coeliac disease (CD). We have previously demonstrated that the immumoglobulin (Ig) A response to tTG in adult CD specifically targets its catalytic core region, containing the active‐site triad of amino acids. The aim of the present study was to investigate this phenomenon in paediatric patients with CD, and to elucidate the contribution of each active‐site residue to epitopes recognised. The specificity of the IgG anti‐tTG response was also investigated and compared with that of the IgA anti‐tTG response, in both paediatric and adult patients with CD.Methods:Wild‐type and novel variants of tTG were generated via site‐directed mutagenesis and expressed as glutathione‐S‐transferase–fusion proteins in Escherichia coli BL‐21. The mutagenic variants of tTG had substitutions of 1, 1, or all of the 3 of the catalytic triad amino acids. All of the recombinant tTGs were tested for their antigenicity in IgA and IgG enzyme‐linked immunosorbent assays with cohorts of paediatric (n = 63) and adult (n = 30) CD sera.Results:Substitution of even 1 amino acid in the catalytic triad resulted in a significant reduction of CD IgA and IgG anti‐tTG binding, with all of the mutant proteins displaying diminished antigenicity compared with the wild‐type protein.Conclusions:The core region of tTG is specifically targeted from early on in disease course by CD patient autoantibodies of both the IgA and IgG class.
Population PK/PD analysis of metformin using the signal transduction model
Authors: Chae Jung‐woo , Baek In‐hwan , Lee Byung‐yo , Cho Seong‐kwon , Kwon Kwang‐il 
Published: March 2012

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Metformin, a biguanide glucose lowering agent, is commonly used to manage type 2 diabetes.• The molecular mechanisms of metformin have not been fully identified, but turnover of biomarkers such as glucose and signalling pathways or translocation of glucose transporters are closely related to the glucose‐lowering effects of metformin.• The PK/PD of metformin have been investigated in healthy humans and patients with type 2 diabetes mellitus and modelling has been performed using an indirect response model.WHAT THIS STUDY ADDS• The purpose of this investigation was to develop a population PK/PD model for metformin using a signal transduction model in healthy humans and predict the PK/PD profile in patients with type 2 diabetes.• The aim was to compare a previous model (a biophase model) with the signal transduction model, and use a more appropriate model to follow the actions of metformin.• Additionally, our developed model was appropriate to predict the time course of plasma metformin and fasting plasma glucose (FPG) concentrations in patients with type 2 diabetes.• To our knowledge, this is the first published population PK/PD analysis using the signal transduction model for metformin.AIMS To develop a population pharmacokinetic (PK) and pharmacodynamic (PD) model for metformin (500 mg) using the signal transduction model in healthy humans and to predict the PK/PD profile in patients with type 2 diabetes.METHODS Following the oral administration of 500 mg metformin to healthy humans, plasma concentrations of metformin were measured using LC‐MS/MS. A sequential modelling approach using NONMEM VI was used to facilitate data analysis. Monte Carlo simulation was performed to predict the antihyperglycaemic effect in patients with type 2 diabetes.RESULTS Forty‐two healthy humans were included in the study. Population mean estimates (relative standard error, RSE) of apparent clearance, apparent volume of distribution and the absorption rate constant were 52.6 l h−1 (4.18%), 113 l (56.6%) and 0.41 h−1, respectively. Covariate analyses revealed that creatinine clearance (CLCR) significantly influenced metformin: CL/F= 52.6 × (CLcr/106.5)0.782. The signal transduction model was applied to describe the antihyperglycaemic effect of metformin. The population means for efficacy, potency, transit time and the Hill coefficient were estimated to be 19.8 (3.17%), 3.68 µg ml−1 (3.89%), 0.5 h (2.89%) and 0.547 (9.05%), respectively. The developed model was used to predict the antihyperglycaemic effect in patients with type 2 diabetes. The predicted plasma glucose concentration value was similar to previous values.CONCLUSIONS The population signal transduction model was developed and evaluated for metformin use in healthy volunteers. Model evaluation by non‐parametric bootstrap analysis suggested that the proposed model was robust and parameter values were estimated with good precision.