628 research outputs found

    Meso-Scale Hydrologic Modeling for Climate Impact Assessments: A Conceptual and A Regresssion Approach

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    The paper presents two different approaches to hydrologic modeling for Climate Impact Assessments: A conceptual water balance model and a non-parametric regression model. They both are designed for modeling large-scale river basins (Meso-Scale) at a monthly time step and to accept GCM-based climate scenarios defined as changes in monthly precipitation and temperature. The data requirements for the models are historical, multi-annual series of mean monthly temperature, precipitation, and runoff. These data are used to calibrate the models. GCM data or user-defined sensitivity of climatic variable must be provided for the assessment analyses. The paper describes the theoretical bases of both approaches and presents the results of a comparison of the application of the models to the Vistula River Basin in Poland

    Will d-amphetamine’s effect on impulsive choice be consistent when the environmental context changes by using decreasing delays to reinforcement?

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    Impulsivity (choosing a smaller, more immediate reward over a larger, more delayed reward) and substance abuse are positively correlated. It is important to understand how factors like delay to reward and drug effects determine impulsive choice, which can be studied using animal models. This study evaluated impulsive choice in rats, where delays to the larger reward (three food pellets) were presented in decreasing order versus one food pellet delivered immediately. Then, effects of d-amphetamine were assessed. It was found that in three of four rats, d-amphetamine increased impulsive choice when the larger option was presented with decreasing delays. This effect is contrary to what has generally been found with increasing delays. Thus, environmental context can influence drug effects on impulsive choice

    Re-Inventing Public Education:The New Role of Knowledge in Education Policy-Making

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    This article focuses on the changing role of knowledge in education policy making within the knowledge society. Through an examination of key policy texts, the Scottish case of Integrated Children Services provision is used to exemplify this new trend. We discuss the ways in which knowledge is being used in order to re-configure education as part of a range of public services designed to meet individuals' needs. This, we argue, has led to a 'scientization' of education governance where it is only knowledge, closely intertwined with action (expressed as 'measures') that can reveal problems and shape solutions. The article concludes by highlighting the key role of knowledge policy and governance in orienting education policy making through a re-invention of the public role of education

    Executive (dys)function after stroke: special considerations for behavioral pharmacology

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    Stroke is a world-wide leading cause of death and long-term disability with concurrent secondary consequences that are largely comprised of mood dysfunction, as well as sensory, motor, and cognitive deficits. This review focuses on the cognitive deficits associated with stroke specific to executive dysfunction (including decision making, working memory, and cognitive flexibility) in humans, non-human primates, and additional animal models. Further, we review some of the cellular and molecular underpinnings of the individual components of executive dysfunction and their neuroanatomical substrates after stroke, with an emphasis on the changes that occur during biogenic monoamine neurotransmission. We concentrate primarily on changes in the catecholaminergic (dopaminergic and noradrenergic) and serotonergic systems at the levels of neurotransmitter synthesis, distribution, re-uptake, and degradation. We also discuss potential secondary stroke-related behavioral deficits (specifically, post-stroke depression as well as drug-abuse potential and addiction) and their relationship with stroke-induced deficits in executive function, an especially important consideration given that the average age of the human stroke population is decreasing. In the final sections, we address pharmacological considerations for the treatment of ischemia and the subsequent functional impairment, as well as current limitations in the field of stroke and executive function research

    Executive (dys)function after traumatic brain injury: special considerations for behavioral pharmacology

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    Executive function is an umbrella term that includes cognitive processes such as decision-making, impulse control, attention, behavioral flexibility, and working memory. Each of these processes depends largely upon monoaminergic (dopaminergic, serotonergic, and noradrenergic) neurotransmission in the frontal cortex, striatum, and hippocampus, among other brain areas. Traumatic brain injury (TBI) induces disruptions in monoaminergic signaling along several steps in the neurotransmission process – synthesis, distribution, and breakdown – and in turn, produces long-lasting deficits in several executive function domains. Understanding how TBI alters monoamingeric neurotransmission and executive function will advance basic knowledge of the underlying principles that govern executive function and potentially further treatment of cognitive deficits following such injury. In this review, we examine the influence of TBI on the following measures of executive function – impulsivity, behavioral flexibility, and working memory. We also describe monoaminergic-systems changes following TBI. Given that TBI patients experience alterations in monoaminergic signaling following injury, they may represent a unique population with regard to pharmacotherapy. We conclude this review by discussing some considerations for pharmacotherapy in the field of TBI

    An analysis of pupil concerns regarding transition into higher education.

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    Transitioning to higher education is often a stressful experience, with incoming students facing similar issues year after year. This chapter presents two years of data collection regarding the concerns of Computing secondary school pupils when considering their upcoming transition into the first year of higher education. Over the two-year period, it can be seen that pupils continue to demonstrate concerns regarding topics related to money, jobs and course achievement as opposed to those related to environment or social issues. The consistency between relative areas of concern over the two years is striking, further suggesting that an understanding of these issues might help higher education institutions to better support their incoming students

    Characterization of proanthocyanidin metabolism in pea (Pisum sativum) seeds

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    BACKGROUND: Proanthocyanidins (PAs) accumulate in the seeds, fruits and leaves of various plant species including the seed coats of pea (Pisum sativum), an important food crop. PAs have been implicated in human health, but molecular and biochemical characterization of pea PA biosynthesis has not been established to date, and detailed pea PA chemical composition has not been extensively studied. RESULTS: PAs were localized to the ground parenchyma and epidermal cells of pea seed coats. Chemical analyses of PAs from seeds of three pea cultivars demonstrated cultivar variation in PA composition. ‘Courier’ and ‘Solido’ PAs were primarily prodelphinidin-types, whereas the PAs from ‘LAN3017’ were mainly the procyanidin-type. The mean degree of polymerization of ‘LAN3017’ PAs was also higher than those from ‘Courier’ and ‘Solido’. Next-generation sequencing of ‘Courier’ seed coat cDNA produced a seed coat-specific transcriptome. Three cDNAs encoding anthocyanidin reductase (PsANR), leucoanthocyanidin reductase (PsLAR), and dihydroflavonol reductase (PsDFR) were isolated. PsANR and PsLAR transcripts were most abundant earlier in seed coat development. This was followed by maximum PA accumulation in the seed coat. Recombinant PsANR enzyme efficiently synthesized all three cis-flavan-3-ols (gallocatechin, catechin, and afzalechin) with satisfactory kinetic properties. The synthesis rate of trans-flavan-3-ol by co-incubation of PsLAR and PsDFR was comparable to cis-flavan-3-ol synthesis rate by PsANR. Despite the competent PsLAR activity in vitro, expression of PsLAR driven by the Arabidopsis ANR promoter in wild-type and anr knock-out Arabidopsis backgrounds did not result in PA synthesis. CONCLUSION: Significant variation in seed coat PA composition was found within the pea cultivars, making pea an ideal system to explore PA biosynthesis. PsANR and PsLAR transcript profiles, PA localization, and PA accumulation patterns suggest that a pool of PA subunits are produced in specific seed coat cells early in development to be used as substrates for polymerization into PAs. Biochemically competent recombinant PsANR and PsLAR activities were consistent with the pea seed coat PA profile composed of both cis- and trans-flavan-3-ols. Since the expression of PsLAR in Arabidopsis did not alter the PA subunit profile (which is only comprised of cis-flavan-3-ols), it necessitates further investigation of in planta metabolic flux through PsLAR. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-014-0238-y) contains supplementary material, which is available to authorized users

    Biogeographic Study of Human Gut-Associated CrAssphage Suggests Impacts From Industrialization and Recent Expansion

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    CrAssphage (cross-assembly phage) is a bacteriophage that was first discovered in human gut metagenomic data. CrAssphage belongs to a diverse family of crAss-like bacteriophages thought to infect gut commensal bacteria belonging to Bacteroides species. However, not much is known about the biogeography of crAssphage and whether certain strains are associated with specific human populations. In this study, we screened publicly available human gut metagenomic data from 3,341 samples for the presence of crAssphage sensu stricto (NC_024711.1). We found that crAssphage prevalence is low in traditional, hunter-gatherer populations, such as the Hadza from Tanzania and Matses from Peru, as compared to industrialized, urban populations. Statistical comparisons showed no association of crAssphage prevalence with variables such as age, sex, body mass index, and health status of individuals. Phylogenetic analyses show that crAssphage strains reconstructed from the same individual over multiple time-points, cluster together. CrAssphage strains from individuals from the same study population do not always cluster together. Some evidence of clustering is seen at the level of broadly defined geographic regions, however, the relative positions of these clusters within the crAssphage phylogeny are not well-supported. We hypothesize that this lack of strong biogeographic structuring is suggestive of an expansion event within crAssphage. Using a Bayesian dating approach, we estimate that this expansion has occurred fairly recently. Overall, we determine that crAssphage presence is associated with an industrialized lifestyle and the absence of strong biogeographic structuring within global crAssphage strains is likely due to a recent population expansion within this bacteriophage.This study was supported by a grant from the National Institutes of Health (https://www.nih.gov/), NIH R01 GM089886, awarded to C.M.L., C.W., and K.S. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

    Origins of an Unmarked Georgia Cemetery Using Ancient DNA Analysis

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    Determining the origins of those buried within undocumented cemeteries is of incredible importance to historical archaeologists and in many cases, the nearby communities. In the case of Avondale Burial Place, a cemetery in Bibb County, Georgia, in use from 1820 to 1950, all written documentation of those interred within it has been lost. Osteological and archaeological evidence alone could not describe, with confidence, the ancestral origins of the 101 individuals buried there. In the present study, we utilize ancient DNA extraction methods to investigate the origins of Avondale Burial Place through the use of well-preserved skeletal fragments from 20 individuals buried in the cemetery. Through examination of hypervariable region I in the mitochondrial genome (HVR1, mtDNA), we determine haplotypes for all 20 of these individuals. A total of 18 of the 20 individuals belong to the L or U haplogroups, suggesting that Avondale Burial Place was most likely used primarily as a resting place for African Americans. After the surrounding Bibb County community expressed interest in investigating potential ancestral relationships to those within the cemetery, a total of eight potential descendants provided saliva in order to obtain mtDNA HVR1 information. This phase of the study revealed that two different individuals from Avondale Burial Place matched two individuals with oral history ties to the cemetery. Using the online tool EMPOP, we calculated the likelihood of these exact matches occurring by chance alone

    Gender and educational leadership in England: a comparison of secondary headteachers' views over time

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    In the context of gender being a barrier to accessing leadership, this paper presents a comparison of the views of men and women head teacher (principals) of secondary schools in England in the 1990s and in 2004. The same survey instrument was used on both occasions. The perceptions of the head teachers show change in some areas and no change in others. Overall, women are more likely to become head teachers and are now less likely to be categorised into pastoral roles, but in some cases women still meet prejudice from governors and others in the wider community. Women head teachers are more likely to have partners and children than in the 1990s, sharing equally or carrying most of the domestic responsibilities, whereas male colleagues are most likely to have partners who take the majority of responsibility in the home. Essentialist stereotypes about women and men as leaders still prevail, although both the women and men head teachers see themselves as adopting a traditionally ‘feminine’ style of leadership. Women head teachers are likely to see some benefits in being a woman in a role stereotypically associated with men. However, there has been an increase in the proportion of women who feel that they have to prove their worth as a leader, and this may be linked with increased levels of accountability in schools
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