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Presents Evidence (present + evidence)
Kinds of Presents Evidence Terms modified by Presents Evidence Selected AbstractsMushroom bodies are not required for courtship behavior by normal and sexually mosaic DrosophilaDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2002Asami Kido Abstract To elucidate the effect of feminization of male Drosophila brain cells on courtship control, we performed a large scale screening of expression drivers that can suppress male-specific behavior with transformer gene expression. Two drivers caused essentially total courtship suppression. The expression pattern of these drivers did not show any correlation with the mushroom bodies or the antennal lobes, the regions that have been suggested to play important roles in courtship. Ablation of mushroom bodies using hydroxyurea treatment did not affect this courtship suppression. The ablation did not change either wild-type heterosexual behavior or bisexual behavior caused by transformer expression driven by the same drivers used in the previous studies to suggest the involvement of the mushroom bodies in courtship. Our results show that feminization of different nonoverlapping cells in other parts of the protocerebrum was sufficient to cause the same bisexual or suppressed-courtship phenotype. Thus, contrary to previous assumptions, the mushroom bodies are not required for the control of courtship. Present evidence supports its mediation by other distributed protocerebral regions. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 302,311, 2002 [source] Adaptive dimensions of health research among indigenous Siberians,AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 2 2007J. Josh Snodgrass Present evidence suggests that modern humans were the first hominid species to successfully colonize high-latitude environments (,55°N). Given evidence for a recent (<200,000 years) lower latitude naissance of modern humans, the global dispersal and successful settlement of arctic and subarctic regions represent an unprecedented adaptive shift. This adaptive shift, which included cultural, behavioral, and biological dimensions, allowed human populations to cope with the myriad environmental stressors encountered in circumpolar regions. Although unique morphological and physiological adaptations among contemporary northern residents have been recognized for decades, human biologists are only now beginning to consider whether biological adaptations to regional environmental conditions influence health changes associated with economic modernization and lifestyle change. Recent studies have documented basal metabolic rates (BMRs) among indigenous Siberian populations that are systematically elevated compared to lower latitude groups; this metabolic elevation apparently is a physiological adaptation to cold stress experienced in the circumpolar environment. Important health implications of metabolic adaptation are suggested by research with the Yakut (Sakha), Evenki, and Buriat of Siberia. BMR is significantly positively correlated with blood pressure, independently of body size, body composition, and various potentially confounding variables (e.g., age and smoking). Further, this research has documented a significant negative association between BMR and LDL cholesterol, which remains after controlling for potential confounders; this suggests that high metabolic turnover among indigenous Siberians has a protective effect with regard to plasma lipid levels. These results underscore the importance of incorporating an evolutionary approach into health research among northern populations. Am. J. Hum. Biol. 19:165,180, 2007. © 2007 Wiley-Liss, Inc. [source] THE QUALITY OF INSTITUTIONS AND FOREIGN DIRECT INVESTMENTECONOMICS & POLITICS, Issue 3 2007CHRISTIAN DAUDE Using bilateral foreign direct investment (FDI) stocks around the world, we explore the importance of a wide range of institutional variables as determinants of the location of FDI. While we find that better institutions have overall a positive and economically significant effect on FDI, some institutional aspects matter more than others do. Especially, the unpredictability of laws, regulations and policies, excessive regulatory burden, government instability and lack of commitment play a major role in deterring FDI. For example, the effect of a one standard deviation improvement in the regulatory quality of the host country increases FDI by a factor of around 2. These results are robust to different specifications, estimation methods, and institutional variables. We also present evidence on the significance of institutions as a determinant of FDI over time. [source] Immune suppression in the honey bee (Apis mellifera) following infection by Nosema ceranae (Microsporidia)ENVIRONMENTAL MICROBIOLOGY, Issue 9 2009Karina Antúnez Summary Two microsporidia species have been shown to infect Apis mellifera, Nosema apis and Nosema ceranae. This work present evidence that N. ceranae infection significantly suppresses the honey bee immune response, although this effect was not observed following infection with N. apis. Immune suppression would also increase susceptibility to other bee pathogens and senescence. Despite the importance of both Nosema species in honey bee health, there is no information about their effect on the bees' immune system and present results can explain the different virulence between both microsporida infecting honeybees. [source] Analysis of the Pseudomonas aeruginosa oprD gene from clinical and environmental isolatesENVIRONMENTAL MICROBIOLOGY, Issue 12 2002Jean-Paul Pirnay Summary Genomes are constantly evolving. Our report highlights the wide mutational diversity of clinical as well as environmental isolates, compared with the laboratory strain(s), through the systematic genetic analysis of a chromosomal porin gene (oprD) in relation to a specific antibiotic resistance. Mutational inactivation of the oprD gene is associated with carbapenem resistance in Pseudomonas aeruginosa. The sequence of the oprD gene of 55 Pseudomonas aeruginosa natural isolates obtained from across the world , from sources as diverse as patients and rhizospheres , was analysed. A microscale mosaic structure for this gene , resulting from multiple intra- and possibly interspecies recombinational events , is reported. An array of independent and seemingly fast-occurring defective oprD mutations were found, none of which had been described before. A burn wound isolate demonstrated unusually high overall sequence variability typical of mutator strains. We also present evidence for the existence of OprD homologues in other fluorescent pseudomonads. [source] Chemotherapy-related nausea and vomiting , past reflections, present practice and future managementEUROPEAN JOURNAL OF CANCER CARE, Issue 1 2004M. MILLER ba (hons), msc (cancer nursing), rgn research fellow Although much progress has occurred in the last decade regarding the management of chemotherapy-induced nausea and vomiting, these remain among the most intolerable side-effects of treatment and patients continue to report the negative impact such symptoms have on their ability to enjoy life. Inadequate control of nausea and vomiting reduces patients' quality of life and functional status and jeopardizes the delivery of optimal treatment, so making its management a priority for oncology health care workers. This article will reflect on past and present evidence regarding the management of chemotherapy-induced nausea and vomiting while highlighting some of the most recent scientific advances before drawing conclusions about the future management of this troublesome symptom for patients receiving chemotherapy. [source] Autoantibodies in alcoholic liver diseaseADDICTION BIOLOGY, Issue 2 2000Ian G. McFarlane Despite many decades of research, the reasons why only a relatively small proportion of individuals who consume excessive quantities of alcohol develop clinically significant liver disease remain unknown. The association with features of autoimmune diseases, including hypergammaglobulinaemia, circulating autoantibodies, inheritance of certain immunogenetic (HLA) markers and response to corticosteroid therapy in some patients has led to a persistent impression that altered immune regulation with a relative loss of self-tolerance underlies susceptibility to the development of the more severe forms of alcoholic liver disease (alcoholic hepatitis and/or cirrhosis). However, review of the data from the numerous studies that have been conducted over the past 30 years fails to reveal sufficiently convincing evidence that autoimmunity plays a primary role in alcohol-related liver damage. In particular, most of the wide range of circulating autoantibodies that have been reported in patients are found mainly at low titres, are not confined to those with severe liver injury, and are probably more likely to be a response to the hepatic insult than causally related to liver damage. Additionally, an association with various HLA phenotypes has not been confirmed by meta-analysis. Interpretation is complicated by evidence that alcohol may have direct effects on some components of the immune system but, if there is an immunogenetic basis for alcoholic liver disease, the present evidence suggests that this might be related more to cytokine gene polymorphisms than to a predisposition to autoimmunity per se. [source] A CENTENNIAL CELEBRATION FOR QUANTITATIVE GENETICSEVOLUTION, Issue 5 2007Derek A. Roff Quantitative genetics is at or is fast approaching its centennial. In this perspective I consider five current issues pertinent to the application of quantitative genetics to evolutionary theory. First, I discuss the utility of a quantitative genetic perspective in describing genetic variation at two very different levels of resolution, (1) in natural, free-ranging populations and (2) to describe variation at the level of DNA transcription. Whereas quantitative genetics can serve as a very useful descriptor of genetic variation, its greater usefulness is in predicting evolutionary change, particularly when used in the first instance (wild populations). Second, I review the contributions of Quantitative trait loci (QLT) analysis in determining the number of loci and distribution of their genetic effects, the possible importance of identifying specific genes, and the ability of the multivariate breeder's equation to predict the results of bivariate selection experiments. QLT analyses appear to indicate that genetic effects are skewed, that at least 20 loci are generally involved, with an unknown number of alleles, and that a few loci have major effects. However, epistatic effects are common, which means that such loci might not have population-wide major effects: this question waits upon (QTL) analyses conducted on more than a few inbred lines. Third, I examine the importance of research into the action of specific genes on traits. Although great progress has been made in identifying specific genes contributing to trait variation, the high level of gene interactions underlying quantitative traits makes it unlikely that in the near future we will have mechanistic models for such traits, or that these would have greater predictive power than quantitative genetic models. In the fourth section I present evidence that the results of bivariate selection experiments when selection is antagonistic to the genetic covariance are frequently not well predicted by the multivariate breeder's equation. Bivariate experiments that combine both selection and functional analyses are urgently needed. Finally, I discuss the importance of gaining more insight, both theoretical and empirical, on the evolution of the G and P matrices. [source] Firm Size, Industry Mix and the Regional Transmission of Monetary Policy in GermanyGERMAN ECONOMIC REVIEW, Issue 1 2004Ivo J. M. Arnold Monetary transmission; regional effects; industry effects; firm size Abstract. This paper estimates the impact of interest rate shocks on regional output in Germany over the period from 1970 to 2000. We use a vector autoregression (VAR) model to obtain impulse responses, which reveal differences in the output responses to monetary policy shocks across ten German provinces. Next, we investigate whether these differences can be related to structural features of the regional economies, such as industry mix, firm size, bank size and openness. An additional analysis of the volatility of real GDP growth for the period 1992,2000 includes the Eastern provinces. We also present evidence on the interrelationship between firm size and industry, and compare our measure of firm size with those used in previous studies. We conclude that the differential regional effects of monetary policy are related to industrial composition, but not to firm size or bank size. [source] How a leading medical lab accrediting organization has achieved breakthrough improvement with transformational leadershipGLOBAL BUSINESS AND ORGANIZATIONAL EXCELLENCE, Issue 4 2010Tammy Roberts COLA, a leading clinical laboratory accreditation organization, faced a rapidly contracting market and worsening financial performance but was paralyzed by outmoded systems and a vision and mind-set hamstrung by attachments to past success. In an eight-year journey, leaders and staff learned to create transformative change in themselves and on key organizational fronts, subsequently generating breakthrough improvements in performance that have set COLA on a new path to success. The authors discuss the key cornerstones of transformational change; a model of transformational leadership; and the transformation cycle COLA used to integrate these with strategic/business planning, execution, and performance monitoring. They also describe COLA's key initiatives,including governance, leadership and culture, performance measurement, sales and marketing, research and development process, and IT,and present evidence of a robust business and organizational transformation at COLA. © 2010 Wiley Periodicals, Inc. [source] Guidelines on the management of secondary prophylaxis of vascular events in stable patients in primary careINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 2 2004D.J. Betteridge Summary Atherothrombosis, thrombus formation superimposed on an existing atherosclerotic plaque, is an acute process leading to ischaemic events such as myocardial infarction, stroke and critical limb ischaemia. Patients presenting with clinical conditions associated with atherothrombosis are at increased risk of subsequent vascular events. The beneficial effect of antiplatelet therapies for short-term and long-term secondary prevention of atherothrombotic events has been established. These guidelines aim to provide evidence-based recommendations that will assist in the antiplatelet-mediated secondary prophylaxis of vascular events in patients with stable cardiovascular disease treated in the primary healthcare setting. Medline and the Cochrane library were accessed using free-text strategies in the domains of antiplatelet agents and antithrombotics. Development of the guidelines was driven by a series of Steering Committee meetings, in which the quality of relevant studies was assessed and identified using narrative summary. These guidelines present evidence and recommendations for the treatment of numerous atherothrombotic indications depending on individual patient circumstances. [source] Conservatism and Cross-Sectional Variation in the Post,Earnings Announcement DriftJOURNAL OF ACCOUNTING RESEARCH, Issue 4 2006GANAPATHI NARAYANAMOORTHY ABSTRACT Accounting conservatism allows me to identify a previously undocumented source of predictable cross-sectional variation in Standardized Unexpected Earnings' autocorrelations viz. the sign of the most recent earnings realization and present evidence that the market ignores this variation ("loss effect"). It is possible to earn returns higher than from the Bernard and Thomas (1990) strategy by incorporating this feature. Additionally, the paper shows that the "loss effect" is different from the "cross quarter" effect shown by Rangan and Sloan (1998) and it is possible to combine the two effects to earn returns higher than either strategy alone. Thus, the paper corroborates the Bernard and Thomas finding that stock prices fail to reflect the extent to which quarterly earnings series differ from a seasonal random walk and extends it by showing that the market systematically underestimates time-series properties resulting from accounting conservatism. [source] ORIGINAL ARTICLE: Extinction of the autochthonous small mammals of Mallorca (Gymnesic Islands, Western Mediterranean) and its ecological consequencesJOURNAL OF BIOGEOGRAPHY, Issue 6 2008Pere Bover Abstract Aim, To investigate the chronology, causes and consequences of the extinction of the autochthonous Pleistocene small mammals of Mallorca. Location, Mallorca (Gymnesic Islands, Balearics, Western Mediterranean). Methods, We have obtained the first direct 14C ages from the bone collagen of selected samples of two extinct endemic small mammals from Mallorca: the Balearic dormouse, Eliomys morpheus (Rodentia: Myoxidae) and the Balearic shrew, Asoriculus hidalgoi (Soricomorpha: Soricidae). We also present evidence for the absence of both endemics from the earliest Mallorcan archaeological sites and for the introduction of the garden dormouse, Eliomys quercinus, and the wood mouse, Apodemus sylvaticus. Combined information from direct dating of bone collagen of E. quercinus and A. sylvaticus and from cultural associations provides an adequate framework to establish the chronology of the faunal change and to compare it with the chronological information available on climatic change and the first arrival of humans on the islands. Results, The chronological record includes the latest evidence available for the survival of endemic species and the earliest introduction of small mammals into Mallorca. We present ,uncertainty periods for extinction' (UPEs) of both endemic mammals based on the chronology of their last occurrence and on the inferred timing of their extinction (restricted UPEs). Main conclusions, Possible causes for the extinction of autochthonous small mammals on Mallorca are discussed. Once we have discarded climatic causes, predation by invasive species, competition with newcomers and habitat deterioration, the introduction of diseases emerges as the most reasonable explanation for these extinctions. Based on the identification of changes in keystone species in Mallorcan ecosystems, we propose a tentative schedule of key ecological changes that have taken place over the past 5 millennia. [source] DILP-producing median neurosecretory cells in the Drosophila brain mediate the response of lifespan to nutritionAGING CELL, Issue 3 2010Susan J. Broughton Summary Dietary restriction extends lifespan in diverse organisms, but the gene regulatory mechanisms and tissues mediating the increased survival are still unclear. Studies in worms and flies have revealed a number of candidate mechanisms, including the target of rapamycin and insulin/IGF-like signalling (IIS) pathways and suggested a specific role for the nervous system in mediating the response. A pair of sensory neurons in Caenorhabditis elegans has been found to specifically mediate DR lifespan extension, but a neuronal focus in the Drosophila nervous system has not yet been identified. We have previously shown that reducing IIS via the partial ablation of median neurosecretory cells in the Drosophila adult brain, which produce three of the seven fly insulin-like peptides, extends lifespan. Here, we show that these cells are required to mediate the response of lifespan to full feeding in a yeast dilution DR regime and that they appear to do so by mechanisms that involve both altered IIS and other endocrine effects. We also present evidence of an interaction between these mNSCs, nutrition and sleep, further emphasising the functional homology between the DILP-producing neurosecretory cells in the Drosophila brain and the hypothalamus of mammals in their roles as integration sites of many inputs for the control of lifespan and behaviour. [source] Views of nature of science questionnaire: Toward valid and meaningful assessment of learners' conceptions of nature of scienceJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 6 2002Norm G. Lederman Helping students develop informed views of nature of science (NOS) has been and continues to be a central goal for kindergarten through Grade 12 (K,12) science education. Since the early 1960s, major efforts have been undertaken to enhance K,12 students and science teachers' NOS views. However, the crucial component of assessing learners' NOS views remains an issue in research on NOS. This article aims to (a) trace the development of a new open-ended instrument, the Views of Nature of Science Questionnaire (VNOS), which in conjunction with individual interviews aims to provide meaningful assessments of learners' NOS views; (b) outline the NOS framework that underlies the development of the VNOS; (c) present evidence regarding the validity of the VNOS; (d) elucidate the use of the VNOS and associated interviews, and the range of NOS aspects that it aims to assess; and (e) discuss the usefulness of rich descriptive NOS profiles that the VNOS provides in research related to teaching and learning about NOS. The VNOS comes in response to some calls within the science education community to go back to developing standardized forced-choice paper and pencil NOS assessment instruments designed for mass administrations to large samples. We believe that these calls ignore much of what was learned from research on teaching and learning about NOS over the past 30 years. The present state of this line of research necessitates a focus on individual classroom interventions aimed at enhancing learners' NOS views, rather than on mass assessments aimed at describing or evaluating students' beliefs. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 497,521, 2002 [source] Guidelines for the laboratory diagnosis of trichomoniasis in East European countriesJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 10 2010M Domeika Abstract The laboratory diagnosis of sexually transmitted infections in many Eastern European countries remains suboptimal. The main objective of the present evidence-based guidelines is to provide comprehensive information regarding the laboratory diagnosis of infections caused by Trichomonas vaginalis in East European countries. In particular, the present guidelines recommend: (i) to encourage examination of the wet mounts of vaginal exudates, instead of stained smears, at all clinical settings; (ii) nucleic acid amplification tests (NAATs) or culture could be employed if no trichomonads are detected on microscopic examination of the wet preparation and there is a strong indication of infection and (iii) the use of NAATs is encouraged in screening, using non-invasive specimens, or high volume testing situations. In the absence of internationally recognized commercial NAAT systems, tests developed in-house should be validated using obtainable international standards and quality assured strictly. Individual East European countries may be required to make minor national adjustments to these guidelines as a result of lack of accessibility to some reagents or equipment, or laws in a specific country. [source] Creep Resistant Polymer Nanocomposites Reinforced with Multiwalled Carbon NanotubesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 8 2007Jinglei Yang Abstract Poly(propylene) (PP) nanocomposites filled with shorter- and longer-aspect-ratio multiwalled carbon nanotubes (MWNTs) were compounded using a twin-screw extruder and an injection moulding machine. It is shown that with only 1 vol.-% of MWNTs, creep resistance of PP can be significantly improved with reduced creep deformation and creep rate at a long-term loading period. Additionally, the creep lifetime of the nanocomposites has been considerably extended by 1,000% compared to that of a neat PP. Three possible mechanisms of load transfer were considered that could contribute to the observed enhancement of creep resistance, which are: (1) fairly good interfacial strength between MWNTs and polymer matrix, (2) increasing immobility of amorphous regions due to nanotubes acting as restriction sites, and (3) high aspect ratio of MWNTs. DSC results showing crystallinity changes in the specimens before and after creep deformation present evidence to confirm these mechanisms. Our results should lead to improved grades of creep resistant polymer nanocomposites for engineering applications. [source] 39Ar- 40Ar dating of the Zagami Martian shergottite and implications for magma origin of excess 40ArMETEORITICS & PLANETARY SCIENCE, Issue 7 2008Donald D. BOGARD 1992, 1999). Like several shergottites, Zagami contains excess 40Ar relative to its formation age. To understand the origin of this excess 40Ar, we made 39Ar- 40Ar analyses on plagioclase and pyroxene minerals from two phases representing different stages in the magma evolution. Surprisingly, all these separates show similar concentrations of excess 40Ar, ,1 × 10,6 cm3/g. We present arguments against this excess 40Ar having been introduced from the Martian atmosphere as impact glass. We also present evidence against excess 40Ar being a partially degassed residue from a basalt that actually formed ,4 Gyr ago. We utilize our experimental data on Ar diffusion in Zagami and evidence that it was shock-heated to only ,70 °C, and we assume this heating occurred during an ejection from Mars ,3 Myr ago. With these constraints, thermal considerations necessitates either that its ejected mass was impossibly large, or that its shock-heating temperature was an order of magnitude higher than that measured. We suggest that this excess 40Ar was inherited from the Zagami magma, and that it was introduced into the magma either by degassing of a larger volume of material or by early assimilation of old, K-rich crustal material. Similar concentrations of excess 40Ar in the analyzed separates imply that this magma maintained a relatively constant 40Ar concentration throughout its crystallization. This likely occurred through volatile degassing as the magma rose toward the surface and lithostatic pressure was released. These concepts have implications for excess 40Ar in other shergottites. [source] New Expression Profiles of Voltage-gated Ion Channels in Arteries Exposed to High Blood PressureMICROCIRCULATION, Issue 4 2002Robert H. Cox The diameters of small arteries and arterioles are tightly regulated by the dynamic interaction between Ca2+ and K+ channels in the vascular smooth muscle cells. Calcium influx through voltage-gated Ca2+ channels induces vasoconstriction, whereas the opening of K+ channels mediates hyperpolarization, inactivation of voltage-gated Ca2+ channels, and vasodilation. Three types of voltage-sensitive ion channels have been highly implicated in the regulation of resting vascular tone. These include the L-type Ca2+ (CaL) channels, voltage-gated K+ (KV) channels, and high-conductance voltage- and Ca2+ -sensitive K+ (BKCa) channels. Recently, abnormal expression profiles of these ion channels have been identified as part of the pathogenesis of arterial hypertension and other vasospastic diseases. An increasing number of studies suggest that high blood pressure may trigger cellular signaling cascades that dynamically alter the expression profile of arterial ion channels to further modify vascular tone. This article will briefly review the properties of CaL, KV, and BKCa channels, present evidence that their expression profile is altered during systemic hypertension, and suggest potential mechanisms by which the signal of elevated blood pressure may result in altered ion channel expression. A final section will discuss emerging concepts and opportunities for the development of new vasoactive drugs, which may rely on targeting disease-specific changes in ion channel expression as a mechanism to lower vascular tone during hypertensive diseases. [source] Horizontally acquired homologues of the nucleoid-associated protein H-NS: implications for gene regulationMOLECULAR MICROBIOLOGY, Issue 2 2010Charles J. Dorman Summary H-NS is one of the most intensively studied members of the family of bacterial nucleoid-associated proteins. It is a DNA-binding protein with a preference for A+T-rich DNA sequences, and it represses the transcription of hundreds of genes in Gram-negative bacteria, including pathogens. In most cases where the issue has been investigated, the repressive activity of H-NS is opposed by the intervention of an antagonistically acting DNA-binding protein, a remodelling of local DNA structure, or a combination of these two. H-NS activity can also be modulated by protein,protein interaction with members of the Hha/YdgT protein family, molecules that share partial amino acid sequence similarity to the oligomerization domain of H-NS. Of particular interest is the ability of H-NS to interact with the full-length paralogue StpA or full-length orthologues that have been acquired by horizontal DNA transfer. In this issue of Molecular Microbiology, Müller et al. describe the H-NS orthologue Hfp and present evidence that in bacteria that acquire Hfp the range of activities of H-NS is modified with important implications for the physiology of the bacterium. [source] Unravelling a histone code for malaria virulenceMOLECULAR MICROBIOLOGY, Issue 6 2007Christy A. Comeaux Summary Epigenetic phenomena have been shown to play a role in the regulated expression of virulence genes in several pathogenic organisms, including the var gene family in Plasmodium falciparum. A better understanding of how P. falciparum can both maintain a single active var gene locus through many erythrocytic cycles and also achieve successive switching to different loci in order to evade the host immune system is greatly needed. Disruption of this tightly co-ordinated expression system presents an opportunity for increased clearance of the parasites by the immune system and, in turn, reduced mortality and morbidity. In the current issue of Molecular Microbiology, Lopez-Rubio and colleagues investigate the correlation of specific post-translational histone modifications with different transcriptional states of a single var gene, var2csa. Quantitative chromatin immunoprecipitation is used to demonstrate that different histone methylation marks are enriched at the 5, flanking and coding regions of active, poised or silenced var genes. They identify an increase of H3K4me2 and H3K4me3 in the 5, flanking region of an active var locus and expand on an earlier finding that H3K9me3 is enriched in the coding regions of silenced var genes. The authors also present evidence that H3K4me2 bookmarks the active var gene locus during later developmental stages for expression in the subsequent asexual cycle, hinting at a potential mechanism for transcriptional ,memory'. The stage is now set for work generating a complete catalogue of all histone modifications associated with var gene regulation as well as functional studies striving to uncover the precise mechanisms underlying these observations. [source] A catalogue and analysis of X-ray luminosities of early-type galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2001Ewan O'Sullivan We present a catalogue of X-ray luminosities for 401 early-type galaxies, of which 136 are based on newly analysed ROSAT PSPC pointed observations. The remaining luminosities are taken from the literature and converted to a common energy band, spectral model and distance scale. Using this sample we fit the LX : LB relation for early-type galaxies and find a best-fit slope for the catalogue of ,2.2. We demonstrate the influence of group-dominant galaxies on the fit and present evidence that the relation is not well modelled by a single power-law fit. We also derive estimates of the contribution to galaxy X-ray luminosities from discrete-sources and conclude that they provide . We compare this result with luminosities from our catalogue. Lastly, we examine the influence of environment on galaxy X-ray luminosity and on the form of the relation. We conclude that although environment undoubtedly affects the X-ray properties of individual galaxies, particularly those in the centres of groups and clusters, it does not change the nature of whole populations. [source] The constant-density region of the dark haloes of spiral galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2001Paolo Salucci We determine a crucial feature of the dark halo density distribution from the fact that the luminous matter dominates the gravitational potential at about one disc scalelength Rd, but at the optical edge the dark matter has already become the main component of the galaxy density. From the kinematics of 137 spirals we find that the dark matter halo density profiles are self-similar at least out to Ropt and show core radii much larger than the corresponding disc scalelengths. The luminous regions of spirals consist of stellar discs embedded in dark haloes with roughly constant density. This invariant dark matter profile is very difficult to reconcile with the fundamental properties of the density distribution of cold dark matter haloes. With respect to previous work, the present evidence is obtained by means of a robust method and for a large and complete sample of normal spirals. [source] Above and below ground impacts of terrestrial mammals and birds in a tropical forestOIKOS, Issue 4 2008Amy E. Dunham Understanding the impact of losing trophic diversity has global significance for managing ecosystems as well as important theoretical implications for community and ecosystem ecology. In several tropical forest ecosystems, habitat fragmentation has resulted in declines and local extinctions of mammalian and avian terrestrial insectivores. To assess the ability of a tropical rainforest community in Ivory Coast to resist perturbation from such loss of trophic diversity, I traced feedbacks in above and below ground communities and measured changes in nutrient levels and herbivory rates in response to an experimental exclosure of avian and mammalian terrestrial insectivores. I present evidence that loss of this functional group may result in increased tree seedling herbivory and altered nutrient regimes through changes in the abundance and guild structure of invertebrates. Exclusion of top predators of the forest floor resulted in increased seedling herbivory rates and macro-invertebrate (>5 mm) densities with strongest effects on herbivorous taxa, spiders and earthworms. Densities of microbivores including Collembola, Acarina and Sciaridae showed the opposite trend as did levels of inorganic phosphorus in the soil. Results were evaluated using path analysis which supported the presence of a top down trophic cascade in the detrital web which ultimately affected turnover of phosphorus, a limiting nutrient in tropical soils. Results illustrate the potential importance of vertebrate predators in both above and belowground food webs despite the biotic diversity and structural heterogeneity of the rainforest floor. [source] The Line-Item Veto in Georgia: Fiscal Restraint or Inter-Branch Politics?PUBLIC BUDGETING AND FINANCE, Issue 2 2006THOMAS P. LAUTH This article about use of the line-item veto in Georgia concludes that the item veto has been used not as an instrument for reducing the budget total or the size of state government, but as an instrument for protecting the executive budget. Using appropriations data and drawing upon interviews with participants in the budget process, including seven governors, the authors present evidence that in Georgia the item veto (1) is not frequently used, (2) when used, is more likely to remove legislative language than delete dollar amounts, and (3) enables the spending priorities and fiscal policy preferences of the governor to prevail as state policy. [source] The ecology and evolutionary endocrinology of reproduction in the human femaleAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue S49 2009Virginia J. Vitzthum Abstract Human reproductive ecology (HRE) is the study of the mechanisms that link variation in reproductive traits with variation in local habitats. Empirical and theoretical contributions from biological anthropology, physiology, and demography have established the foundation necessary for developing a comprehensive understanding, grounded in life history theory (LHT), of temporal, individual, and populational variation in women's reproductive functioning. LHT posits that natural selection leads to the evolution of mechanisms that tend to allocate resources to the competing demands of growth, reproduction, and survival such that fitness is locally maximized. (That is, among alternative allocation patterns exhibited in a population, those having the highest inclusive fitness will become more common over generational time.) Hence, strategic modulation of reproductive effort is potentially adaptive because investment in a new conception may risk one's own survival, future reproductive opportunities, and/or current offspring survival. The hypothalamic-pituitary-ovarian (HPO) axis is the principal neuroendocrine pathway by which the human female modulates reproductive functioning according to the changing conditions in her habitat. Adjustments of reproductive investment in a potential conception are manifested in temporal and individual variation in ovarian cycle length, ovulation, hormone levels, and the probability of conception. Understanding the extent and causes of adaptive and non-adaptive variation in ovarian functioning is fundamental to ascertaining the proximate and remote determinants of human reproductive patterns. In this review I consider what is known and what still needs to be learned of the ecology of women's reproductive biology, beginning with a discussion of the principal explanatory frameworks in HRE and the biometry of ovarian functioning. Turning next to empirical studies, it is evident that marked variation between cycles, women, and populations is the norm rather than an aberration. Other than woman's age, the determinants of these differences are not well characterized, although developmental conditions, dietary practices, genetic variation, and epigenetic mechanisms have all been hypothesized to play some role. It is also evident that the reproductive functioning of women born and living in arduous conditions is not analogous to that of athletes, dieters, or even the lower end of the "normal range" of HPO functioning in wealthier populations. Contrary to the presumption that humans have low fecundity and an inefficient reproductive system, both theory and present evidence suggest that we may actually have very high fecundity and a reproductive system that has evolved to be flexible, ruthlessly efficient and, most importantly, strategic. Yrbk Phys Anthropol 52:95,136, 2009. © 2009 Wiley-Liss, Inc. [source] Intravenous magnesium sulfate in acute severe asthmaRESPIROLOGY, Issue 3 2000Chaichan Boonyavorakul Objective: Intravenous magnesium sulfate (MgSO4), as an adjunctive medication to the standard treatment of acute asthma, improves admission rate or severity score in acute severe asthma patients. Methodology: We conducted a randomized double-blind placebo controlled trial with subjects from the emergency room, Ramathibodi Hospital, Bangkok, Thailand. Patients, aged 15,65 years with acute severe asthma attack, whose severity scores were greater than 4 and who were willing to be enrolled in a study during March to November 1997 participated in the study. Randomly allocated patients received either 2 g intravenous MgSO4 or placebo, sterile water, as an adjunctive medication to standard therapy for acute asthma. The medication was diluted in 50 mL of 0.9% normal saline. Measurement: Severity scores were measured by two investigators using Fischl's indices. The times interval of measurements were at the initial (0), 60, 120, 180, and 240 min from receipt of treatment. Patients were hospitalized if the severity scores at 240 min exceeded 1. Risk ratio (RR) and 95% confidence interval (CI) of RR were applied to estimate the risk of admission. Analysis of variance with repeated measurement on time was used to determine the severity score between two groups. Results: Thirty-four patients with acute severe asthma were enrolled in the present study. One patient from the placebo group was excluded because he did not consent to undergoing peak expiratory flow rate. Seventeen patients received MgSO4 and 16 patients received placebo. The general characteristics between the two groups were not significantly different, which reflected the quality of randomization. The admission rates of the placebo and MgSO4 group were 25.00% and 17.65%, respectively. Patients who received MgSO4 had preventive risk to be hospitalized 0.71 times relative to patients who received placebo. However, this preventive risk did not reach statistical significance (95% CI of RR = 0.19,2.67). The severity score at any time between the two groups was also not statistically significantly different (P = 0.366). Conclusion: With the present evidence, the hypothesis was not confirmed. Magnesium sulphate as an adjunct to standard therapy did not improve either admission rate or severity score in patients with acute severe asthma. [source] Neurobiological Processes in Adolescent Addictive DisordersTHE AMERICAN JOURNAL ON ADDICTIONS, Issue 1 2008Ty S. Schepis PhD The purpose of this review is to summarize the neurobiological factors involved in the etiology of adolescent addiction and present evidence implicating various mechanisms in its development. Adolescents are at heightened risk for experimentation with substances, and early experimentation is associated with higher rates of SUD in adulthood. Both normative (e.g., immature frontal-limbic connections, immature frontal lobe development) and non-normative (e.g., lowered serotonergic function, abnormal hypothalamic-pituitary-adrenal axis function) neurobiological developmental factors can predispose adolescents to a heightened risk for SUD. In addition, a normative imbalance in the adolescent neurobiological motivational system may be caused by the relative underdevelopment of suppressive mechanisms when compared to stimulatory systems. These neurobiological liabilities may correspond to neurobehavioral impairments in decision-making, affiliation with deviant peers and externalizing behavior; these and other cognitive and behavioral traits converge with neurobiological factors to increase SUD risk. The progression to SUD acts as an amplifying feedback loop, where the development of SUD results in reciprocal impairments in neurobehavioral and neurobiological processes. A clearer understanding of adolescent neurobiology is a necessary step in the development of prevention and treatment interventions for adolescent SUD. [source] COMPETITIVE ISSUES IN THE TAIWANESE BANKING INDUSTRY: MERGERS AND UNIVERSAL BANKSTHE DEVELOPING ECONOMIES, Issue 3 2003Peiyi YU This paper investigates scale economies and scope economies in the Taiwanese banking system, looking beyond the market-power (MP) and efficient-structure (ES) hypotheses. Given the existence of overall economies of scale and the positive value of expansion path sub-additivity, we conclude that there might be large increases in profits following mergers. Moreover, since the profit-structure relationship after financial reform is determined by the relative-market-power hypothesis, this consolidation trend will not necessarily decrease the social benefit for Taiwanese consumers. With regard to scope economies and product-specific economies of scale, we are unable to recommend whether Taiwanese banks should develop as specialized banks or diversified banks in the future. Finally, we find that risk indicators play an important role in explaining the observed variation in bank profitability, and present evidence that default risk and leverage risk have negative effects on the profits of banking, although the effect of portfolio risk is uncertain. [source] The impact of after-school programs on the routine activities of middle-school students: Results from a randomized, controlled trial,CRIMINOLOGY AND PUBLIC POLICY, Issue 2 2009Amanda Brown Cross Research Summary Unsupervised after-school time for adolescents is a concern for parents and policymakers alike. Evidence linking unsupervised adolescent socializing to problem behavior outcomes heightens this concern among criminologists. Routine activities theory suggests that, when youth peer groups congregate away from adult authority, both opportunity for and motivation to engage in deviant acts increase. After-school programs are a possible solution to unsupervised teen socializing during afternoon hours and are much in demand. However, empirical research has yet to test the relationship between the availability of after-school programs and youth routine activities. This study presents evidence from a multisite, randomized, controlled trial of an after-school program for middle-school students in an urban school district. Policy Implications Youth in the treatment group engaged in less unsupervised socializing after school than youth in the control group but not as much less as would be expected if the after-school program was providing consistent supervision to youth who would otherwise be unsupervised. Additional analyses examined why the influence of the after-school program was not more pronounced. We found that, although program attendance was related to decreases in unsupervised socializing, the program did not attract many delinquency-prone youths who were unsupervised, which suggests that the students most in need of the program did not benefit. Furthermore, data obtained from a mid-year activity survey revealed that youth in the study were highly engaged in a variety of after-school activities. The addition of the after-school program into the mixture of available activities had little effect on the frequency with which students participated in organized activities after school. [source] | ||||||||||||||||||||||||||||