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Considerable Contribution (considerable + contribution)
Selected AbstractsCoxsackievirus B4 and type 1 diabetes pathogenesis: contribution of animal modelsDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 7 2009H. Jaïdane Abstract The role of enteroviruses, in particular type B coxsackieviruses (CV-B), in type 1 diabetes (T1D) pathogenesis is supported by epidemiological, clinical and experimental observations. The investigation of T1D pathogenesis benefits from the contribution of animal models called spontaneously diabetic. Among these animals the non-obese diabetic (NOD) mouse and the bio-breeding diabetes-prone (BBDP) rat present a genetic susceptibility manifested by the expression of an autoimmune diabetes similar to the pathology observed in human beings. Other models whose genetic predisposition is less known are of considerable contribution as well. Numerous major observations relative to several aspects of T1D pathogenesis in the context of CV-B infections, such as susceptibility, diabetogenicity, pancreatotropism, mechanisms of , cells destruction and others, have been deduced thanks to investigations with animal models. Despite their limits, these models are necessary in improving our knowledge of the role of enteroviruses, like CV-B4, in the pathogenesis of T1D, and the recent advances ensuing from their contribution may have important therapeutic and preventive spin-offs. Copyright © 2009 John Wiley & Sons, Ltd. [source] Formation of 2,4,D complexes on montmorillonites , an ab initio molecular dynamics studyEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2007D. Tunega Summary Sorption of the anionic form of the pesticide 2,4,D (2,4,dichlorophenoxyacetic acid) on the surface of the clay mineral montmorillonite was investigated using a short-time ab initio molecular dynamics (MD) simulation at room temperature. Three different situations were modelled: sorption on a dry surface, on a hydrated surface and an intercalation between montmorillonite layers. In all three cases, the calcium cation compensates the excess negative charge of the montmorillonite layer and the negative charge of the 2,4,D anion. It was found that in all models with direct contact of the Ca2+ cation with the montmorillonite layer, the most stable position of Ca2+ is above the ditrigonal hole of the mineral layer. While in the case of a dry surface very stable bidentate binding is created between the 2,4,D anion and the Ca2+ cation, the formation of the monodentate complexes is preferred in all models that include water molecules. Hydrogen bonds formed between water molecules and the 2,4,D anion make a considerable contribution to the formation of the monodentate complexes. Tetrahedral substitutions in the montmorillonite layer have a significant effect on the formation of the complexes of any type. However, the MD simulations did not support the role of Ca2+ as a cation bridge in the adsorption mechanism. Calculations showed that hydrated 2,4,D···Ca2+ complexes are thermodynamically more stable than complexes in which the Ca2+ cation acts as a bridge to the surface. On the other hand, it is possible that phyllosilicates with a greater concentration of isomorphic substitutions (e.g. mica) will be able to form stable surface complexes with a cation bridge mechanism. [source] Multilevel analysis of effects of individual characteristics and household factors on self-rated health among older adults in rural VietnamGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 2 2010Hoang Van Minh Aim: This paper aims to describe self-rated health (SRH) status among older adults in a rural community of Vietnam, and examine individual and household-level factors associated with good health rating among the study populations. Methods: The study was carried out in the Bavi district, a rural community located 60 km west of Hanoi, the capital, within the Epidemiological Field Laboratory of Bavi (FilaBavi) in Vietnam in 2006. All people aged 50 years and over who lived within the district were surveyed. Face-to-face household interviews were conducted by trained surveyors using standard World Health Organization/INDEPTH network questionnaire,summary version. A logistic multilevel modeling approach was applied to analyze the association between SRH and both individual and household-level factors. Results: The proportion of people aged 50 years and older in FilaBavi reported having good/very good health and poor/very poor health was 15.1% and 24.8%, respectively. SRH status was reported to be better among: (i) men; (ii) younger people; (iii) people with higher education; (iv) people who were currently in marital a partnership; (v) those from wealthier households; and (vi) those who were living in riverside/island or highland areas compared to those of other categories of the same variable. Conclusion: The findings reveal that there exist problems of inequality in health among older adults in the study setting by sex, age, education, wealth status and place of residence. We also found a considerable contribution of the household-level factors to SRH of the study populations.. [source] Intra-seasonal variability of wintertime temperature over East AsiaINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2004Dao-Yi Gong Abstract There has been a profound warming over East Asia during the winter months (November through to March) over the past few decades. The goal of this study is to address the question of whether the daily temperature has become more variable in conjunction with this warming by using observed temperature data obtained from 155 Chinese and Korean stations. Prior to the analysis, the annual cycle is removed to obtain daily temperature anomalies for each winter for each station. Results show that the intra-seasonal variance generally decreases, implying that the daily temperatures are becoming less variable. Considering all stations as a whole, the rate of change is ,0.49°C2 per decade (equivalent to ,3.59% per decade). The changes are more robust in the northeastern portion of China. In contrast, there are no dominant trends for the skewness coefficients, except for clear negatively skewed trends in northeastern China. These results are consistent with an increase in the number of extremely cold events. Over the region, the frequency of low-temperature extremes (as low as below minus two standard deviations) increases at a rate of change of 0.26 days per decade, significant at the 95% confidence level. Both the Siberian high and Arctic oscillation (AO) exert a notable influence on the temperature variance. Intra-seasonal variance of the Siberian high and AO are significantly correlated with the temperature variance, whereas the seasonal mean state of the AO affects the temperature variance by modulating the high-frequency components of the Siberian high. The intra-seasonal variance of the Siberian high tends to decline at a rate of change of ,10.7% per decade, significant at the 99% level; meanwhile, the mean wintertime AOs have strengthened in the last few decades. These two climate features together make a considerable contribution to the changes in intra-seasonal temperature variance in East Asia. Copyright © 2004 Royal Meteorological Society [source] Breeding success in Blue Tits: good territories or good parents?JOURNAL OF AVIAN BIOLOGY, Issue 3 2001Robert Przybylo Territorial quality and parental quality are usually assumed to be the main sources of variation in the reproductive success of passerine birds. To evaluate their relative importance for variation in breeding time (itself an important factor for breeding success), clutch size and offspring condition at fledging, we analysed six years of data from a Blue Tit Parus caeruleus population breeding on the island of Gotland, Sweden. Hatching dates and the condition of offspring were consistent for territories between years and accounted for 30% and 33% of the variation in these variables, respectively. After removing the effect of territory quality, none of the breeding parameters were significantly repeatable for individual females, but offspring condition was repeatable for males, accounting for 28% of variation. For females breeding on the same territory in subsequent seasons (combined effect of individual and territory quality) only hatching date was repeatable (45% of variation accounted for). In males, the combined effect of individual and territory quality was repeatable for offspring condition and accounted for 33% of variation, but this result was only marginally significant. Consistency of the peak frass-fall date for individual frass collectors over the study period suggests that repeatable hatching dates on territories may be related to the relationship between timing of breeding and timing of peak food availability on territories. Our results suggest that territory quality is more important than parental quality for breeding success in the Blue Tit, and that male (but not female) quality makes a considerable contribution to reproductive success. [source] Evaluation of the capacity of three halophytes to desalinize their rhizosphere as grown on saline soils under nonleaching conditionsAFRICAN JOURNAL OF ECOLOGY, Issue 4 2009Mokded Rabhi Abstract In the sabkha of Soliman (N-E Tunisia), soil samples of the upper 20 cm were taken during the driest period of the year (July,August) from inside and outside tufts of two perennial halophytes: Arthrocnemum indicum (Willd.) Moq. and Suaeda fruticosa Forssk., both from family Chenopodiaceae. Samples were analysed for electrical conductivity of the saturation paste extract (ECe) and soluble sodium (Na+) content. Then, tufts were divided into three size categories and their shoot biomass production and Na+ content were determined. Our results showed a considerable contribution of shoot Na+ accumulation to rhizosphere desalination. The capacity of the two native halophytes A. indicum. and S. fruticosa to desalinize saline soils was compared with that of an introduced halophyte, Sesuvium portulacastrum L. (Aizoaceae). Seedlings were grown under greenhouse conditions in pots containing 8 kg of saline soil each. Pots were irrigated with tap water during 170 days without leaching. Our results confirmed the contribution of shoot Na+ accumulation to soil desalination. They showed also that among the three studied species, Sesuvium portulacastrum L. seems to be the most convenient to be used for this purpose in arid and semi-arid regions where precipitation is too low to leach salts from rhizosphere. Résumé Dans la sebkha de Soliman (N-E de la Tunisie), des échantillons de sol ont été prélevés dans les 20 cm supérieurs pendant la période la plus sèche de l'année (juillet-août) à l'intérieur et à l'extérieur des touffes de deux halophytes pérennes, Arthrocnemum indicum (Willd) Moq. et Suaeda fructicosa Forsk., appartenant tous deux à la famille des Chenopodiaceae. L'analyse des échantillons s'est basée sur la conductivitéélectrique de la pâte saturée (ECe) et le contenu en sodium (Na+) soluble. Par ailleurs, les touffes d'halophytes ont été réparties en trois catégories selon leur taille, puis des touffes représentatives de chaque catégorie ont été récoltées pour la détermination de la biomasse et la charge en Na+ de leurs parties aériennes. Nos résultats ont montré que l'accumulation de ces ions au niveau des organes aériens contribue considérablement au dessalement de la rhizosphère. La capacité des deux halophytes locales A. indicum et S. fructicosa de dessaler des sols salins a été comparée à celle d'un halophyte introduite, Sesuvium portulacastrum L. (Aizoaceae). De jeunes plantules ont été cultivées sous serre dans des pots contenant chacun huit kilos de sol salin. Les pots ont été irrigués à l'eau de ville pendant 170 jours sans lessivage. Nos résultats ont confirmé la contribution de l'accumulation de Na+ par les organes photosynthétiques au dessalement du sol. Ils ont montré, également, que, parmi les trois espèces étudiées, S. portulacastrum semble être la plus prometteuse pour un tel programme dans les régions arides et semi-arides où les précipitations sont assez faibles pour lessiver les sels de la rhizosphère. [source] (4,4-Difluoro-4-bora-3a,4a,-diaza-s-indacen-3-yl)acetaldehyde: Synthesis and chemical propertiesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2009Mykola P. Shandura A reaction of 3,5-dimethylborondipyrromethene 3 with the DMF dimethylacetal gives rise to monoenamine 4. The latter is converted to the corresponding aldehyde 5. A considerable contribution of the enolic form of the aldehyde allows preparing numerous 3-vinyl substituted borondipyrromethenes and some heterocyclic derivatives. A reaction of the aldehyde 5 with tertiary aliphatic amines and the consecutive Hofmann-type decomposition of the intermediary quaternary salt give rise to the corresponding dialkylaminovinyl derivatives. J. Heterocyclic Chem., (2009). [source] Raman spectra and elastic properties of KPb2Cl5 crystalsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2004A. N. Vtyurin Abstract Raman scattering spectra and elastic constants of KPb2Cl5 crystals have been studied. The results obtained are interpreted in terms of the ab initio lattice dynamics model taking into account multipole moments of ionic electron envelopes. The experimental results have been found to be in good agreement with numerical simulation; the narrow phonon spectra are shown to be due to a considerable contribution of heavy cations into the eigenvectors of the higher frequency lattice modes. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Genetic approaches and technologies for improving the sustainability of livestock production,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2004Stephen C Bishop Abstract Livestock production industries worldwide face considerable conflicting challenges and pressures. In developed countries the challenge is to remain sustainable and competitive in the face of declining prices and increasing costs, competition and public pressures. In developing countries the strong increase in demand for livestock products must be met in circumstances where infrastructure is often minimal, there are limitations on inputs and the environment places demands on management and on the adaptive fitness of the livestock. In both situations, solutions to these problems must be sustainable and appropriate, yet be technically feasible, cost-effective and publicly acceptable. This paper summarises the impact of two technologies that will make considerable contributions to sustainable livestock production systems, namely information technology and genetic technologies that utilise naturally occurring genetic variation. Genetic technologies are inherently sustainable owing to the permanent and cumulative nature of genetic change, and range from simple to sophisticated. They include breed choice, within-breed selection and the use of genetic markers linked to gene variants conferring favourable attributes. Breeding goals include increased output, where required, enhanced product quality and increased disease resistance. These goals are illustrated by examples for the hill sheep and pig sectors in the UK and by challenges facing animal health in developing countries. Central to all examples is the gathering, management and interpretation of information, ie information technology, which enables rational genetic and management decisions to be made. Additionally, in all sustainable livestock production systems the maintenance and utilisation of biodiversity will help manage the risks of today as well as the challenges of the future. Copyright © 2004 Society of Chemical Industry [source] An Australian Outlook on International Affairs?AUSTRALIAN JOURNAL OF POLITICS AND HISTORY, Issue 3 2009The Evolution of International Relations Theory in Australia Disciplinary histories of Australian International Relations (IR) theory have tended to focus on the 1960s , when a number of Australian scholars returned from the UK to take up posts at the Australian National University's Department of International Relations , as the beginning of a discipline that has subsequently flourished through various disciplinary debates and global events. This article offers a preliminary attempt at narrating a more complete history of Australian IR by beginning to recover much-neglected contributions made in the early interwar years. From these earliest years through to the current "era of critical diversity", it is argued, Australian scholars have made considerable contributions not just to the intellectual formation of an Australian outlook on international affairs, but to an understanding of international relations itself. [source] | |||||||||||||||||||