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Diverse Set (diverse + set)
Selected AbstractsExploring type I angiotensin (AT1) receptor functions through gene targetingACTA PHYSIOLOGICA, Issue 4 2004S. D. Crowley Abstract The renin,angiotensin system (RAS) modulates a diverse set of physiological processes including development, blood pressure, renal function and inflammation. The principal effector molecule of this system, angiotensin II, mediates most of these actions. The classically recognized functions of the RAS are triggered via the type 1 (AT1) class of angiotensin receptors. Pharmacological blockade of the AT1 receptor lowers blood pressure and slows the progression of cardiovascular and renal diseases. Gene-targeting technology provides an experimental approach for precisely dissecting the physiological functions of the RAS. Here, we review how gene-targeting experiments have elucidated AT1 receptor functions. [source] The Paradoxes of Environmental Policy and Resource Management in Reform-Era China,ECONOMIC GEOGRAPHY, Issue 3 2000Joshua Muldavin Abstract: Over the last 5,000 years serious environmental problems,deforestation, desertification, erosion, and widespread pollution of air, land, and water,have prevailed throughout most of China, brought about by a diverse set of social and political contexts. In this paper I focus on an enduring contradiction associated with the post-1978 reforms, namely accelerated environmental resource degradation in rural areas amid unprecedented national economic growth. Declining entitlements to assets and social capital in China's rural village populations are a crucial aspect of altered state-peasant relations, as these are increasingly mediated by the market during China's transition to a hybrid economy. This has resulted in changing patterns of resource use, impacting both the environment and peasant livelihoods. A brief assessment of China's postrevolutionary environmental policy and management practices provides the context for detailed case studies in Henan Province. These examples highlight the relationship between political-economic changes and environmental policy and management. Contrary to reform rhetoric, rural peasants' embracing of reform policies does not necessarily optimize their welfare or promote sustainable use of resources. The case studies reveal alternative pathways for villages, ones that ought to be brought into the policy debate spotlight. [source] Development and application of the human intestinal tract chip, a phylogenetic microarray: analysis of universally conserved phylotypes in the abundant microbiota of young and elderly adultsENVIRONMENTAL MICROBIOLOGY, Issue 7 2009-Stojanovi, Mirjana Rajili Summary In this paper we present the in silico assessment of the diversity of variable regions of the small subunit ribosomal RNA (SSU rRNA) gene based on an ecosystem-specific curated database, describe a probe design procedure based on two hypervariable regions with minimal redundancy and test the potential of such probe design strategy for the design of a flexible microarray platform. This resulted in the development and application of a phylogenetic microarray for studying the human gastrointestinal microbiota , referred as the human intestinal tract chip (HITChip). Over 4800 dedicated tiling oligonucleotide probes were designed based on two hypervariable regions of the SSU rRNA gene of 1140 unique microbial phylotypes (< 98% identity) following analysis of over 16 000 human intestinal SSU rRNA sequences. These HITChip probes were hybridized to a diverse set of human intestinal samples and SSU rRNA clones to validate its fingerprinting and quantification potential. Excellent reproducibility (median Pearson's correlation of 0.99) was obtained following hybridization with T7 polymerase transcripts generated in vitro from SSU rRNA gene amplicons. A linear dose,response was observed with artificial mixtures of 40 different representative amplicons with relative abundances as low as 0.1% of total microbiota. Analysis of three consecutively collected faecal samples from ten individuals (five young and five elderly adults) revealed temporal dynamics and confirmed that the adult intestinal microbiota is an individual-specific and relatively stable ecosystem. Further analysis of the stable part allowed for the identification of a universal microbiota core at the approximate genus level (90% sequence similarity). This core consists of members of Actinobacteria, Bacteroidetes and Firmicutes. Used as a phylogenetic fingerprinting tool with the possibility for relative quantification, the HITChip has the potential to bridge the gaps in our knowledge in the quantitative and qualitative description of the human gastrointestinal microbiota composition. [source] Structure,activity relationships for gene activation oestrogenicity: Evaluation of a diverse set of aromatic chemicalsENVIRONMENTAL TOXICOLOGY, Issue 1 2002T. Wayne Schultz Abstract Structure,activity relationships for oestrogenicity were developed based on 120 aromatic chemicals evaluated in the Saccharomyces cerevisiae -based Lac -Z reporter assay. Relative gene activation was compared to 17,-estradiol and varied over eight orders of magnitude. Analysis of the data compared to 17,-estradiol identified three structural criteria that were related to xenoestrogen activity and potency: (1) the hydrogen-bonding ability of the phenolic ring mimicking the A-ring, (2) a hydrophobic centre similar in size and shape to the B- and C-rings, and (3) a hydrogen-bond donor mimicking the 17,-hydroxyl moiety of the D-ring, especially with an oxygen-to-oxygen distance similar to that between the 3- and 17,-hydroxyl groups of 17,-estradiol. Binding data were segregated into activity clusters including strong, moderate, weak, and detectable gene expression, and those compounds that were inactive. The hydrogen-bonding ability of hydroxy group in the 3-position on 17,-estradiol was observed to be essential for gene activation. Compounds with a 4-hydroxyl substituted benzene ring and a hydrophobic moiety of size and shape equivalent to the B-ring of 17,-estradiol were generally observed to be weakly active compounds. Moderately active compounds have a 4-hydroxyl substituted benzene ring with a hydrophobic moiety equivalent in size and shape to the B- and C-ring of 17,-estradiol, or have a high hydrogen-bond donor capacity owing to the presence of halogens on a nonphenolic ring. Strongly active compounds, similar to 4,4,-diethylethylene bisphenol (DES), possess the same hydrophobic ring structure as described for moderately active compounds and an additional hydroxyl group with an oxygen-to-oxygen distance close to that exhibited by the 3- and 17-hydroxyl groups of 17,-estradiol. © 2002 by Wiley Periodicals, Inc. Environ Toxicol 17: 14,23, 2002 [source] Prediction of biodegradation from the atom-type electrotopological state indicesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2001Jarmo Huuskonen Abstract A group contribution method based on atom-type electrotopological state indices for predicting the biodegradation of a diverse set of 241 organic chemicals is presented. Multiple linear regression and artificial neural networks were used to build the models using a training set of 172 compounds, for which the approximate time for ultimate biodegradation was estimated from the results of a survey of an expert panel. Derived models were validated by using a leave-25%-out method and against two test sets of 12 and 57 chemicals not included in the training set. The squared correlation coefficient (r2) for a linear model with 15 structural parameters was 0.76 for the training set and 0.68 for the test set of 12 molecules. The model predicted correctly the biodegradation of 48 chemicals in the test set of 57 molecules, for which biodegradability was presented as rapid or slow. The use of artificial neural networks gave better prediction for both test sets when the same set of parameters was tested as inputs in neural network simulations. The predictions of rapidly biodegradable chemicals were more accurate than the predictions of slowly bio-degradable chemicals for both the regression and neural network models. [source] The Contribution of Bioenergy to a New Energy ParadigmEUROCHOICES, Issue 3 2005Daniel De La Torre Ugarte Biomass is a widely available resource that is receiving increased consideration as a renewable substitute for fossil fuels. Developed sustainably and used efficiently, it can induce growth in developing countries, reduce oil demand, and address environmental problems. The potential benefits include: reduction of greenhouse gases, recuperation of soil productivity and degraded land, economic benefits from adding value to agricultural activities and improving access to and quality of energy services. The production of bioenergy involves a range of technologies, including solid combustion, gasification, and fermentation. These technologies produce energy from a diverse set of biological resources - traditional crops, crop residues, energy-dedicated crops, dung, and the organic component of urban waste. The results are bioenergy products that provide multiple energy services: cooking fuel, heat, electricity and transportation fuels. It is this very diversity that holds the potential of a win-win-win for the environment, social and economic development. Bioenergy has to be viewed not as a replacement for oil, but as an element of a portfolio of renewable sources of energy. Coherent and mutually supportive environmental and economic policies may be needed to encourage the emergence of a globally dispersed bioenergy industry that will pursue a path of sustainable development. La biomasse est une resource largement répandue, qui commence à retenir l'attention comme substitut renouvelable aux énergies fossiles. En l'utilisant de façon efficace et durable, on peut accélérer la croissance des pays en voie de développement, réduire la demandepour le pétrole et résoudre certains problèmes d'environnement. Au nombre des bénéfices potentiels il faut mettre : la réduction des émissions de gaz à effet de serre, la reconstitution de la fertilité dessols et des terres dégradées, les avantages économiques liés à l'accroissement de la production agricole et à l'amélioration des services énergétiques, tant en qualité qu'en accessibilité. La production de bioénergie met en oeuvre un large éventail de techniques parmi lesquelles la combustionde produits solides, la gazéification et la fermentation. Elles produisent de l'énergie à partir d'une grande variété de sources biologiques : cultures traditionnelles, résidus de cultures, cultures spécialisées, fumiers et déchets organiques urbains. Les produits bio-énergétiques qui en résultent couvrent une grande variété d'usages : énergie de cuisson, chauffage, électricité et transports. C'est précisément sur cette diversité que repose l'espoir de gains dans toutes les directions, sociales, environnementales et économiques. Il ne faut pas voir la bioénergie comme un simple substitut au pétrole, mais comme un portefeuille de ressources renouvelables. Pour encourager l'émergence d'une industrie bioénergétique largement répandue et susceptible de contribuer au développement durable, il faudra sans doute élaborer des politiques économiques et environnementales cohérentes, capables de se soutenir mutuellement. Bei Biomasse handelt es sich umeine weithin verfügbare Ressource, welche zunehmend als erneuerbarer Ersatz für fossile Brennstoffe in Betracht gezogen wird. Sie kann bei nachhaltiger Entwicklung und effizienter Nutzung zu Wachstum in den Entwicklungsländern führen, die Nachfrage nach Öl senken und dazu beitragen, die Umweltprobleme in den Griff zu bekommen. Zu den potenziellen Nutzen gehÖren: Verringerung der Treibhausgase, Wiederherstellung von Bodenproduktivität sowie von erodiertem Land, wirtschaftlicher Nutzen durch zusätzliche Wertschöpfung aus landwirtschaftlicher Aktivität und besserer Zugang zu und Qualität in der Energieversorgung. Bei der Erzeugungvon Bioenergie kommen eine Reihe von verschiedenen Technologien zur Anwendung, z.B. Verbrennung fester Brennstoffe, Vergasung sowie Gärung. Diese Technologien erzeugen Energie mittels unterschiedlicher biologischer Ressourcen , traditionelle Feldfrüchte und deren Rückstände, spezielle Energiepflanzen, Mist sowie der organische Anteil städtischer Abfälle. Die daraus erzeugte Bioenergie kann zum Kochen, zum Heizen, als Elektrizität oder als Treibstoff genutzt werden. Gerade in dieser Vielfalt liegt der potenzielle Gewinn für die Umwelt und die soziale sowie die wirtschaftliche Entwicklung. Bioenergie sollte nicht als ein Ersatz für Öl, sondern als Bestandteil des Portfolios erneuerbarer Energiequellen angesehen werden. Kohärente und sich gegenseitig unterstützende ökologische und Ökonomische Politikmaßnahmen könntenerforderlich sein, um die Entstehung einer global verbreiteten Bioenergieindustrie zu begünstigen, welche eine nachhaltige Entwicklung verfolgt. [source] ASSORTATIVE MATING FOR FITNESS AND THE EVOLUTION OF RECOMBINATIONEVOLUTION, Issue 7 2006Alistair Blachford Abstract To understand selection on recombination, we need to consider how linkage disequilibria develop and how recombination alters these disequilibria. Any factors that development of disequilbria, including nonrandom mating, can potentially change selectio on recombination. Assortative mating is known to affect linkage disequilbria but its effect on the evolution of recombination have not been previously studied. Given that assortative arise indirectly via a number of biologically realistic scenarios, it is plausible that weak assortative mating occurs across a diverse set of taxa. Using a modifier model, we examine how assortative mating for fitness affects the evolution of recombination under two evolutionary scenarios: selective sweeps and mutation-selection balance. We find there is no net effect of assortative mating during a selective sweep. In contrast, assortative mating could have a large effect on recombination when deleterious alleles are maintained at mutation-selection balance but only if assortative mating is sufficiently strong. Upon considering reasonable values for the number of loci affecting fitness components, the strength of selection, and the mutation rate, we conclude that the correlation in fitness between mates is unlikely to be sufficiently high for assortative mating to affect the evolution of recombination in most species. [source] Interpreting the smells of predation: how alarm cues and kairomones induce different prey defencesFUNCTIONAL ECOLOGY, Issue 6 2009Nancy M. Schoeppner Summary 1.,For phenotypically plastic organisms to produce phenotypes that are well matched to their environment, they must acquire information about their environment. For inducible defences, cues from damaged prey and cues from predators both have the potential to provide important information, yet we know little about the relative importance of these separate sources of information for behavioural and morphological defences. We also do not know the point during a predation event at which kairomones are produced, i.e. whether they are produced constitutively, during prey attack or during prey digestion. 2.,We exposed leopard frog tadpoles (Rana pipiens) to nine predator cue treatments involving several combinations of cues from damaged conspecifics or heterospecifics, starved predators, predators only chewing prey, predators only digesting prey or predators chewing and digesting prey. 3.,We quantified two behavioural defences. Tadpole hiding behaviour was induced only by cues from crushed tadpoles. Reduced tadpole activity was induced only by cues from predators digesting tadpoles or predators chewing + digesting tadpoles. 4.,We also quantified tadpole mass and two size-adjusted morphological traits that are known to be phenotypically plastic. Mass was unaffected by the cue treatments. Relative body length was affected (i.e. there were differences among some treatments), but none of the treatments significantly differed from the no-predator control. Relative tail depth was affected by the treatments and deeper tails were induced only when tadpoles were exposed to cues from predators digesting tadpoles or cues from predators chewing + digesting tadpoles. 5.,These results demonstrate that some prey species can discriminate among a diverse set of potential cues from heterospecific prey, conspecific prey and predators. Moreover, the results illustrate that the cues responsible for the full suite of behavioural and morphological defences are not induced by tadpole crushing nor can they be induced by generalized digestive chemicals produced when predators digest their prey. Instead, both prey damage and predator digestion of conspecific tissues appear to be important for communicating predatory risk to phenotypically plastic anuran prey. Importantly, the production of chemical cues by predators may be unavoidable and prey have evolved the ability to eavesdrop on these signals. [source] Global change and carnivore body size: data are stasisGLOBAL ECOLOGY, Issue 2 2009Shai Meiri ABSTRACT Aim, Global warming and other anthropogenic changes to the environment affect many aspects of biology and have often been invoked as causing body size changes in vertebrates. Here we examine a diverse set of carnivore populations in search of patterns in body size change that could reflect global warming (in accord with Bergmann's rule). Location, Global. Methods, We used > 4400 specimens representing 22 carnivore species in 52 populations collected over the last few decades to examine whether size changed with collection date when geography and sex are accounted for. We then examined several factors related to global warming, body mass, diet, and the attributes of the different datasets, to see whether they affect the standardized slope (,) of the size versus time regression. Results, Six of 52 populations we examined show a significant effect of year of collection on body size at the 0.05 probability level. The response of size to global warming does not reflect spatial patterns of size variation, nor do diet or body mass affect tendency of populations to change in body size. Size changes are no more pronounced in populations that have been sampled more recently. However, change, where it occurs, is rapid. Main conclusions, There may be a tendency in the literature to report only cases where recent changes are prevalent. Although in our data only a minority of populations show body size changes, we may see changes accelerating in the future in response to more drastic climatic changes and other anthropogenic changes. [source] There's more to macroecology than meets the eyeGLOBAL ECOLOGY, Issue 6 2006Tim M. Blackburn ABSTRACT Macroecology sits at the junction of, and can contribute to, the fields of ecology, biogeography, palaeontology and macroevolution, using a broad range of approaches to tackle a diverse set of questions. Here, we argue that there is more to macroecology than mapping, and that while they are potentially useful, maps are insufficient to assess macroecological pattern and process. The true nature of pattern can only be assessed, and competing hypotheses about process can only be disentangled, by adopting a statistical approach, and it is this that has been key to the development of macroecology as a respected and rigorous scientific discipline. [source] Is there a cost of reproduction for Marsh Tits Parus palustris in a primeval forest?IBIS, Issue 1 2006OWSKI TOMASZ We looked for evidence of a cost of reproduction in the Marsh Tit Parus palustris living in the last fragments of primeval temperate forest (Bia,owie,a National Park, eastern Poland). Potential nest-holes were superabundant but the birds had to cope with a diverse set of predators, dangerous both to broods and to parents. Taking advantage of the natural variation in realized reproductive investment that this caused in terms of the loss of nests or mates, we expected to find differences in survival and future fecundity between birds which had lost broods (reduced effort), had reared young (controls) or were either provisioning young single-handed or had laid replacement clutches (increased effort). Despite 13 years of observation, even during seasons with very strenuous conditions, we have failed to demonstrate that the observed range of variation in parental investment caused any demographic cost of reproduction. Incubating females were regularly killed on the nest, which could indicate the existence of a cost operating in the earlier stages of the breeding cycle. Overall, these results suggest that the reproductive rate in Marsh Tits is not controlled proximately by reproductive cost. [source] Onset of promiscuous gene expression in murine fetal thymus organ cultureIMMUNOLOGY, Issue 3 2006Renato Sousa Cardoso Summary T-cell differentiation and induction of tolerance to self-antigens occurs mainly in the thymus. Thymic stromal cells, specifically medullary thymic epithelial cells, express a diverse set of genes encoding parenchymal organ-specific proteins. This phenomenon has been termed promiscuous gene expression (PGE) and has been implicated in preventing organ-specific autoimmunity by inducing T-cell tolerance to self antigens. Early thymopoiesis and the critical factors involved in T-cell differentiation can be reproduced in vitro by murine fetal thymus organ culture (FTOC), which mimics the natural thymic microenvironment. To evaluate the occurrence of PGE in FTOC, gene expression profiling during in vitro thymic development in BALB/c mice was performed using a set of nylon cDNA microarrays containing 9216 sequences. The statistical analysis of the microarray data (sam program) revealed the temporal repression and induction of 57 parenchymal and seven lymphoid organ-specific genes. Most of the genes analysed are repressed during early thymic development (15,17 days post-coitum). The expression of the autoimmune regulator (AIRE) gene at 16 days post-coitum marks the onset of PGE. This precedes the induction of parenchymal organ genes during the late developmental phase at 20 days post-coitum. The mechanism of T-cell tolerance induction begins during fetal development and continues into adulthood. Our findings are significant because they show a fine demarcation of PGE onset, which plays a central role in induction of T-cell tolerance. [source] Applications of the DM-GRASP heuristic: a surveyINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 4 2008Luis F. Santos Abstract Recent research has shown that the hybridization of metaheuristics is a powerful mechanism to develop more robust and efficient methods to solve hard optimization problems. The combination of different techniques and concepts behind metaheuristics, if well designed, has the potential to exploit their advantages while diminishing their drawbacks, which results in methods suited to a more diverse set of real problems. The DM-GRASP heuristic is one such hybrid method that has achieved promising results. It is a hybrid version of the GRASP metaheuristic that incorporates a data-mining process. In this work, we review how this hybridization was designed and survey the results of its practical applications evaluated until now. [source] Viable ultramicrocells in drinking waterJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2009F.S. Silbaq Abstract Aims:, To examine the diversity of cultivable 0·2 micron filtrate biofilm forming bacteria from drinking water systems. Methods and Results:, Potable chlorinated drinking water hosts phylogenetically diverse ultramicrocells (UMC) (0·2 and 0·1 ,m filterable). UMC (starved or dwarf bacteria) were isolated by cultivation on minimal medium from a flow system wall model with polyvinyl chloride (PVC) pipes. All cultivated cells (25 different isolates) did not maintain their ultra-size after passages on rich media. Cultured UMC were identified by their 16S ribosomal DNA sequences. The results showed that they were closely related to uncultured and cultured members of the Proteobacteria, Actinobacteria and Firmicutes. The isolates of phylum Actinobacteria included representatives of a diverse set of Actinobacterial families: Micrococcaceae, Microbacteriaceae, Dermabacteraceae, Nocardiaceae and Nocardioidaceae. Conclusions:, This study is the first to show an abundance of cultivable UMC of various phyla in drinking water system, including a high frequency of bacteria known to be involved in opportunistic infections, such as Stenotrophomonas maltophilia, Microbacterium sp., Pandoraea sp. and Afipia strains. Significance and Impact of the Study:, Chlorinated tap water filtrate (0·2 and 0·1 ,m) still harbours opportunistic micro-organisms that can pose some health threat. [source] Occurrence and life history correlates of vocal duetting in North American passerinesJOURNAL OF AVIAN BIOLOGY, Issue 1 2008Lauryn Benedict Vocal duetting, where two birds produce temporally coordinated vocalizations, has been reported in a taxonomically and geographically diverse set of avian species. Researchers have suggested a number of potential correlates of duetting, including long term monogamy, year-round territory defense and sexual plumage monomorphism. Because the majority of duetting species are tropical, they have been the focus of the most comprehensive studies to date. There is, therefore, a real need for data regarding avian duets in temperate species. I used the recently completed Birds of North America species reports to examine the frequency, evolutionary origins and potential life history correlates of duetting behavior in North American passerines. "Duetting" behavior was reported in 7% of species from 12 avian families, likely representing 17 separate evolutionary origins. Duetting species showed apparent long term monogamy and year-round territoriality at frequencies more than double those of non-duetting passerines: 65% of duetting species were long term monogamous, compared to 27% of non-duetting species, and 50% of duetting species defended the same territory throughout the year, compared with only 11% of non-duetting species. Duetting and non-duetting species showed statistically indistinguishable frequencies of sexual plumage monomorphism. Comparative analyses of duetting species and their sister taxa revealed that the shift to duetting is accompanied by a gain of long term monogamy and year-round territoriality more often than it is associated with a loss of those traits. This study provides intriguing summary evidence that selective factors promoting duetting may be associated with a sedentary, monogamous lifestyle, and may operate similarly across taxonomic groups. Furthermore, vocal duetting may be considerably more common among temperate-zone species than previously recognized. [source] Climatic responses in spring migration of boreal and arctic birds in relation to wintering area and taxonomyJOURNAL OF AVIAN BIOLOGY, Issue 5 2006Kalle Rainio Large-scale climate fluctuations, such as the North Atlantic Oscillation (NAO), have a marked effect on the timing of spring migration of birds. It has however been suggested that long-distance migrants wintering in Africa could respond less to NAO than short-distance migrants wintering in Europe, making them more vulnerable to climatic changes. We studied whether migratory boreal and arctic bird species returning from different wintering areas show differences in responses to the NAO in the timing of their spring migration. We used data on 75 species from two bird observatories in northern Europe (60°N). By extending the examination to the whole distribution of spring migration and to a taxonomically diverse set of birds, we aimed at finding general patterns of the effects of climate fluctuation on the timing of avian migration. Most species arrived earlier after winters with high NAO index. The degree of NAO-response diminished with the phase of migration: the early part of a species' migratory population responded more strongly than the later part. Early phase waterfowl responded strongest to NAO, but in later phases their response faded to non-significant. This pattern may be related to winter severity and/or ice conditions in the Baltic. In the two other groups, gulls and waders and passerines, all phases of migration responded to NAO and fading with phase was non-significant. The difference between waterfowl and other groups may be related to differences between the phenological development of their respective macrohabitats. Wintering area affected the strength of NAO response in a complicated way. On average medium distance migrants responded most strongly, followed by short-distance migrants and partial migrants. Our results concerning the response of long-distance migrants were difficult to interpret: there is an overall weak yet statistically significant effect, but patterns with phase of migration need further study. Our results highlight the importance of examining the whole distribution of migration and warrant the use of data sets from several sampling sites when studying climatic effects on the timing of avian life-history events. [source] A novel semi-empirical topological descriptor Nt and the application to study on QSPR/QSARJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2007Congyi Zhou Abstract A novel semi-empirical topological descriptor Nt was proposed by revising the traditional distance matrix based on the equilibrium electronegativity and the relative bond length. Nt can not only efficiently distinguish structures of organic compounds containing multiple bonds and/or heteroatoms, but also possess good applications of QSPR/QSAR (quantitative structure-property/activity relationships) to a large diverse set of compounds, which are alkanes, alkenes, alkynes, aldehydes, ketones, thiols, and alkoxy silicon chlorides with all the correlation coefficients of the models over 0.99. The LOO CV (leave-one-out cross-validation) method was used to testify the stability and predictive ability of the models. The validation results verify the good stability and predictive ability of the models employing the cross-validation parameters: RCV, SEPCV and SCV, which demonstrate the wide potential of the Nt descriptor for applications to QSPR/ QSAR. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007 [source] Accurate prediction of the blood,brain partitioning of a large set of solutes using ab initio calculations and genetic neural network modelingJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 11 2006Bahram Hemmateenejad Abstract A genetic algorithm-based artificial neural network model has been developed for the accurate prediction of the blood,brain barrier partitioning (in logBB scale) of chemicals. A data set of 123 logBB (115 old molecules and 8 new molecules) of a diverse set of chemicals was chosen in this study. The optimum 3D geometry of the molecules was estimated by the ab initio calculations at the level of RHF/STO-3G, and consequently, different electronic descriptors were calculated for each molecule. Indeed, logP as a measure of hydrophobicity and different topological indices were also calculated. A three-layered artificial neural network with backpropagation of an error-learning algorithm was employed to process the nonlinear relationship between the calculated descriptors and logBB data. Genetic algorithm was used as a feature selection method to select the most relevant set of descriptors as the input of the network. Modeling of the logBB data by the only quantum descriptors produced a 5:4:1 ANN structure with RMS error of validation and crossvalidation equal to 0.224 and 0.227, respectively. Better nonlinear model (RMSV and RMSCV equals to 0.097 and 0.099, respectively) was obtained by the incorporation of the logP and the principal components of the topological indices to electronic descriptors. The ultimate performances of the models were obtained by the application of the models to predict the logBB of 23 molecules that did not have contribution in the steps of model development. The best model produced RMS error of prediction 0.140, and could predict about 98% of variances in the logBB data. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1125,1135, 2006 [source] Consumer Experiences with Predatory Lending PracticesJOURNAL OF CONSUMER AFFAIRS, Issue 1 2007RONALD PAUL HILL This investigation examines how consumers perceive and experience predatory lenders. Findings reveal that industry practices are carried out to the detriment of persons typically defined as "vulnerable," such as elderly, impoverished, and African American consumers. Using a series of personal interviews with a geographically diverse set of respondents, data reveal thematic categories that include the friendly veneer, the rules of engagement, and an aggressive response, which capture the nuances of this exchange relationship from the perspective of these unwitting consumers. The closing section provides implications for scholars and regulators seeking workable solutions to limit additional financial exploitation. [source] What determines African bilateral aid receipts?,JOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 8 2005Mark McGillivray This paper empirically models aid allocation to four African countries,Egypt, Kenya, Morocco and Tanzania,using 1968,1999 time series data. The econometric method employed allows for the joint determination of aid to these countries and for recipient-specific coefficients. It is hypothesised that aid to these countries has been determined by a diverse set of determinants, ranging from their developmental needs or requirements through to donor commercial, political and strategic interests. A special interest of the paper is whether policy regimes have impacted on the amounts of aid received by these countries. Results indicate that they have for all four countries, although the direction of influence differs among them. Copyright © 2005 John Wiley & Sons, Ltd. [source] The influence of top management team attention patterns on global strategic posture of firmsJOURNAL OF ORGANIZATIONAL BEHAVIOR, Issue 7 2005Orly Levy Drawing upon the managerial cognition and the upper echelons perspectives, this study proposes that the cognitive capabilities of top executives significantly affect globalization efforts. Specifically, the study suggests that managerial attention patterns or the cognitive processes of [noticing and constructing meaning] about the environment influence strategic posture of firms. Based on a longitudinal sample of U.S. firms operating in technologically intensive industries, the results indicate that firms were more likely to develop an expansive global strategic posture when their top management paid attention to the external environment and considered a diverse set of elements in this environment. On the other hand, firms led by top management that paid more attention to the internal environment were less likely to be global. Copyright © 2005 John Wiley & Sons, Ltd. [source] The confounding role of personality and trait affectivity in the relationship between job and life satisfactionJOURNAL OF ORGANIZATIONAL BEHAVIOR, Issue 7 2002Daniel Heller Previous research has demonstrated a strong positive relationship between job and life satisfaction. Traditionally, this relationship has been explained in terms of a spillover model, wherein job experiences spill over onto life, and vice versa. This study directly tests a different explanation for this relationship: personality traits that influence both job and life satisfaction. In a longitudinal test with multisource data, three typologies, which were shown by past research to be linked to both job and life satisfaction, were examined: Big Five, positive and negative affectivity, and core self-evaluations. One hundred and fifty-three university employees working in a diverse set of occupations were surveyed twice, with a six month time interval; the first survey also included a second questionnaire to be completed by a ,significant other.' Analyses of concurrent and prospective zero-order and partial correlations, as well as structural equation modeling, supported the hypothesized confounding role of all three typologies, especially core self-evaluations. Though controlling for personality reduced the magnitude of the job,life satisfaction relationship, it did not entirely eliminate it. Overall, the results suggest the presence of both dispositional and environmental factors in job and life satisfaction. Finally, implications for organizational practice and theory development are discussed. Copyright © 2002 John Wiley & Sons, Ltd. [source] Synthesis and characterization of a series of diverse poly(2-oxazoline)sJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2009Kristian Kempe Abstract This article describes the synthesis and characterization of a variety of new poly(2-oxazoline)s. With regard to functional polymers, 2-oxazolines represent an interesting class of monomers because of the easy variation of the substituent in 2-position. Starting from the corresponding nitriles, different 2-oxazolines were obtained containing a diverse set of 2-substituents, including thioether bonds (M11), trifluoromethyl groups (M8, M10), and alkyl- or aryl groups (M1,M7). The subsequent polymerization of the majority of these monomers proceeded in a living manner, which was demonstrated by linear first-order kinetics, a linear increase of molar mass with conversion, and relatively narrow molar mass distributions. In addition, selected thermal and surface properties of the polymers were studied utilizing DSC and contact-angle measurements to determine the effects of different 2-substituents on the macroscopic properties. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3829,3838, 2009 [source] LOOKING FORWARD, PUSHING BACK AND PEERING SIDEWAYS: ANALYZING THE SUSTAINABILITY OF INDUSTRIAL SYMBIOSISJOURNAL OF SUPPLY CHAIN MANAGEMENT, Issue 4 2009PRATIMA BANSAL This paper compares and contrasts two different forms of interorganizational relationships that deal with the production and movement of waste: industrial symbiosis and supply chains. Industrial symbiosis reuses, recycles and reprocesses byproducts and intermediates within the system of organizations, whereas conventional supply chains reduce waste within manufacturing processes and reuse end-of-life products. Although both these models address waste, there is surprisingly little consideration of industrial symbiosis within supply chain research. Yet, industrial symbiosis has much to offer the study of sustainable development within supply chains. Industrial symbiosis emphasizes community, cooperation and coordination among firms, which serves to protect the environmental integrity, social equity and economic prosperity of the region , all hallmarks of sustainable development. However, such tight integration among a diverse set of organizations is difficult to jump start and difficult to maintain. In this paper, we also outline the challenges and offer some ideas on how to address these challenges. We ground our insights from interviews with firms in the Sarnia-Lambton region of Ontario, Canada. This region is home to over 130,000 people, and has a strong physical infrastructure and social structures that have facilitated symbiotic relationships among local businesses. [source] Modelling concurrency of events in on-line auctions via spatiotemporal semiparametric modelsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 1 2007Wolfgang Jank Summary., We introduce a semiparametric approach for modelling the effect of concurrent events on an outcome of interest. Concurrency manifests itself as temporal and spatial dependences. By temporal dependence we mean the effect of an event in the past. Modelling this effect is challenging since events arrive at irregularly spaced time intervals. For the spatial part we use an abstract notion of ,feature space' to conceptualize distances among a set of item features. We motivate our model in the context of on-line auctions by modelling the effect of concurrent auctions on an auction's price. Our concurrency model consists of three components: a transaction-related component that accounts for auction design and bidding competition, a spatial component that takes into account similarity between item features and a temporal component that accounts for recently closed auctions. To construct each of these we borrow ideas from spatial and mixed model methodology. The power of this model is illustrated on a large and diverse set of laptop auctions on eBay.com. We show that our model results in superior predictive performance compared with a set of competitor models. The model also allows for new insight into the factors that drive price in on-line auctions and their relationship to bidding competition, auction design, product variety and temporal learning effects. [source] The Cross-linguistic Study of Sentence ProductionLINGUISTICS & LANGUAGE COMPASS (ELECTRONIC), Issue 4 2009T. Florian Jaeger The mechanisms underlying language production are often assumed to be universal, and hence not contingent on a speaker's language. This assumption is problematic for at least two reasons. Given the typological diversity of the world's languages, only a small subset of languages has actually been studied psycholinguistically. And, in some cases, these investigations have returned results that at least superficially raise doubt about the assumption of universal production mechanisms. The goal of this paper is to illustrate the need for more psycholinguistic work on a typologically more diverse set of languages. We summarize cross-linguistic work on sentence production (specifically: grammatical encoding), focusing on examples where such work has improved our theoretical understanding beyond what studies on English alone could have achieved. But cross-linguistic research has much to offer beyond the testing of existing hypotheses: it can guide the development of theories by revealing the full extent of the human ability to produce language structures. We discuss the potential for interdisciplinary collaborations, and close with a remark on the impact of language endangerment on psycholinguistic research on understudied languages. [source] Popular Magazines, Popular Culture: Gradations of Celebrity in the Romantic PeriodLITERATURE COMPASS (ELECTRONIC), Issue 8 2010Brian Rejack Celebrity and popular culture emerged simultaneously, and synergistically, in part through the agency of the periodical press during the romantic period. As modes of fame multiplied, the audience of celebrity understood itself as a collective,often British, polite, class-oriented,and as individuals modeled through the individualized celebrity that periodicals could project. This process,centered on fashion and fame,integrated notions of the popular and the common with those of the spectacular and the unique. For emerging discourses that consolidated middle-class ideals, such as gastronomy, sports, and contemporary etiquette, the popular magazines occupied a crucial position in what Jon Klancher has denominated "the social text" and helped legitimize themselves by producing their own localized celebrities. Exploring articles from a range of periodicals on a diverse set of topics, this essay shows the reliance of popular magazines on popular culture, understood both in terms of those celebrities of popularity and those commonplace games, sports, and activities associated with the populace. [source] Quantitative structure property relationship models for the prediction of liquid heat capacityMOLECULAR INFORMATICS, Issue 1 2003Xiaojun Yao Abstract Quantitative Structure-Property Relationship (QSPR) models based on molecular descriptors derived from molecular structures have been developed for the prediction of liquid heat capacity at 25,°C using a diverse set of 871 organic compounds. The molecular descriptors used to represent molecular structures include constitutional and topological indices and quantum chemical parameters. Forward stepwise regression and radial basis function neural networks (RBFNNs) were used to construct the QSPR models. The root mean square errors in liquid heat capacity predictions for the training, test and overall data sets are 16.857, 18.744 and 17.141 heat capacity units, respectively. The prediction results are in agreement with the experimental values, but the RBFNN model seems to be better than stepwise regression method. [source] Training and support for evaluability assessment methodologyNEW DIRECTIONS FOR EVALUATION, Issue 125 2010Thearis A. Osuji The authors describe training of a network of professionals to conduct evaluability assessments for the Early Assessment of Programs and Policies on Childhood Obesity Initiative (Early Assessment Initiative). We learned that (1) the professionals trained had a diverse set of skills and expertise, (2) a training refresher session solidified methods and concepts, (3) evaluability assessments were improved when training included content on qualitative interviewing and development and application of logic models, and (4) comprehensive and consistent training methods helped to ensure consistency and methodological integrity. © Wiley Periodicals, Inc., and the American Evaluation Association. [source] Molecular Tools to Study Physcomitrella patensPLANT BIOLOGY, Issue 3 2005W. Frank Abstract: The moss Physcomitrella patens has become a suitable model plant system for the analysis of diverse aspects of modern plant biology. The research strategies have been influenced by the implementation of state-of-the-art cell culture and molecular biology techniques. The forthcoming completion of the Physcomitrella genome sequencing project will generate many open questions, the examination of which will rely on a diverse set of molecular tools. Within this article, we intend to introduce the essential cell culture and molecular biology techniques which have been adopted in recent years to make Physcomitrella amenable to a wide range of genetic analyses. Many research groups have made valuable contributions to improve the methodology for the study of Physcomitrella. We would like to apologise to all colleagues whose important contributions could not be cited within this manuscript. [source] | |||||||||||||||||||||||||||||||||||||