28 research outputs found

    Measurement of Soil Water Potential by Adsorption Conductivity

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    Current methods of measuring soil water potential are reviewed, and the limitations of each are noted. The need for a transducer that will measure soil water potential over a wide moisture range for long periods of time is delineated. The concept of utilizing an adsorptive surface that resembles the soil in its water holding capacity as a transducer is discussed. Various designs and materials are tested for such a transducer. All designs tested did not fulfill the requirements needed for a truly useful transducer. However, experimental results show that modification of the adsorptive surface should allow construction of a unit that will be useful in soil water research

    Managing Protein in Spring Wheat with Aerial and Satellite Imagery

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    Nitrogen fertilizer application can help wheat growers increase crop value and marketability by increasing grain quality. Nitrogen (N) is often applied at heading as a method of increasing protein content and therefore quality of wheat. Our objectives were to obtain spectral signatures of wheat under various N rates (0, 72, 180, 234 kg N ha-1), test various spectral methods of identifying crop stress, and observe the grain protein response to a midseason N application. Spectral data from satellite and aerial platforms were compared to preseason N treatments and flag-leaf tissue samples. Spectral data correlated well with preseason and flag leaf tissue analysis (r2 = 0.58-0.82). Grain protein increased on plots that received an additional 54 kg of N ha-1 at anthesis almost 2% in the N stressed plots (72 kg N ha-1) and 0.3-0.4% on plots with sufficient N (234 and 180 kg N ha-1). Wheat stress detected and managed with help from satellite and aerial platforms could help growers increase revenue and decrease N over-application

    Integrating Statistical Predictions and Experimental Verifications for Enhancing Protein-Chemical Interaction Predictions in Virtual Screening

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    Predictions of interactions between target proteins and potential leads are of great benefit in the drug discovery process. We present a comprehensively applicable statistical prediction method for interactions between any proteins and chemical compounds, which requires only protein sequence data and chemical structure data and utilizes the statistical learning method of support vector machines. In order to realize reasonable comprehensive predictions which can involve many false positives, we propose two approaches for reduction of false positives: (i) efficient use of multiple statistical prediction models in the framework of two-layer SVM and (ii) reasonable design of the negative data to construct statistical prediction models. In two-layer SVM, outputs produced by the first-layer SVM models, which are constructed with different negative samples and reflect different aspects of classifications, are utilized as inputs to the second-layer SVM. In order to design negative data which produce fewer false positive predictions, we iteratively construct SVM models or classification boundaries from positive and tentative negative samples and select additional negative sample candidates according to pre-determined rules. Moreover, in order to fully utilize the advantages of statistical learning methods, we propose a strategy to effectively feedback experimental results to computational predictions with consideration of biological effects of interest. We show the usefulness of our approach in predicting potential ligands binding to human androgen receptors from more than 19 million chemical compounds and verifying these predictions by in vitro binding. Moreover, we utilize this experimental validation as feedback to enhance subsequent computational predictions, and experimentally validate these predictions again. This efficient procedure of the iteration of the in silico prediction and in vitro or in vivo experimental verifications with the sufficient feedback enabled us to identify novel ligand candidates which were distant from known ligands in the chemical space

    A hierarchical Bayesian model for understanding the spatiotemporal dynamics of the intestinal epithelium

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    Our work addresses two key challenges, one biological and one methodological. First, we aim to understand how proliferation and cell migration rates in the intestinal epithelium are related under healthy, damaged (Ara-C treated) and recovering conditions, and how these relations can be used to identify mechanisms of repair and regeneration. We analyse new data, presented in more detail in a companion paper, in which BrdU/IdU cell-labelling experiments were performed under these respective conditions. Second, in considering how to more rigorously process these data and interpret them using mathematical models, we use a probabilistic, hierarchical approach. This provides a best-practice approach for systematically modelling and understanding the uncertainties that can otherwise undermine the generation of reliable conclusions-uncertainties in experimental measurement and treatment, difficult-to-compare mathematical models of underlying mechanisms, and unknown or unobserved parameters. Both spatially discrete and continuous mechanistic models are considered and related via hierarchical conditional probability assumptions. We perform model checks on both in-sample and out-of-sample datasets and use them to show how to test possible model improvements and assess the robustness of our conclusions. We conclude, for the present set of experiments, that a primarily proliferation-driven model suffices to predict labelled cell dynamics over most time-scales

    Structure of the human κ-opioid receptor in complex with JDTic

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    Opioid receptors mediate the actions of endogenous and exogenous opioids on many physiological processes, including the regulation of pain, respiratory drive, mood, and—in the case of κ-opioid receptor (κ-OR)—dysphoria and psychotomimesis. Here we report the crystal structure of the human κ-OR in complex with the selective antagonist JDTic, arranged in parallel dimers, at 2.9 Å resolution. The structure reveals important features of the ligand-binding pocket that contribute to the high affinity and subtype selectivity of JDTic for the human κ-OR. Modelling of other important κ-OR-selective ligands, including the morphinan-derived antagonists norbinaltorphimine and 5′-guanidinonaltrindole, and the diterpene agonist salvinorin A analogue RB-64, reveals both common and distinct features for binding these diverse chemotypes. Analysis of site-directed mutagenesis and ligand structure–activity relationships confirms the interactions observed in the crystal structure, thereby providing a molecular explanation for κ-OR subtype selectivity, and essential insights for the design of compounds with new pharmacological properties targeting the human κ-OR

    European consensus statement on diagnosis and treatment of adult ADHD: The European Network Adult ADHD.

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    BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is among the most common psychiatric disorders of childhood that persists into adulthood in the majority of cases. The evidence on persistence poses several difficulties for adult psychiatry considering the lack of expertise for diagnostic assessment, limited treatment options and patient facilities across Europe. METHODS: The European Network Adult ADHD, founded in 2003, aims to increase awareness of this disorder and improve knowledge and patient care for adults with ADHD across Europe. This Consensus Statement is one of the actions taken by the European Network Adult ADHD in order to support the clinician with research evidence and clinical experience from 18 European countries in which ADHD in adults is recognised and treated. RESULTS: Besides information on the genetics and neurobiology of ADHD, three major questions are addressed in this statement: (1) What is the clinical picture of ADHD in adults? (2) How can ADHD in adults be properly diagnosed? (3) How should ADHD in adults be effectively treated? CONCLUSIONS: ADHD often presents as an impairing lifelong condition in adults, yet it is currently underdiagnosed and treated in many European countries, leading to ineffective treatment and higher costs of illness. Expertise in diagnostic assessment and treatment of ADHD in adults must increase in psychiatry. Instruments for screening and diagnosis of ADHD in adults are available and appropriate treatments exist, although more research is needed in this age group

    Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes

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    publisher: Elsevier articletitle: Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes journaltitle: Cell articlelink: https://doi.org/10.1016/j.cell.2018.05.046 content_type: article copyright: © 2018 Elsevier Inc

    Modeling Spring Wheat Production as Influenced by Climate and Irrigation

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    A model has been developed that predicts spring wheat grain and dry matter yield. Preliminary tests show very favorable results when predicting grain yield in two different climatic regimes, one being a dryland and another being an irrigated area. The strenghts of the model lie in its simplicity, relatively available input data, and low computer processing time cost. Weakness of the model stem from the assumptions that allow its simplicity. The basic assumption in the model is that grain and dry matter yield can be related to the ratio of actual to potential transpiration, computed for each of five phenological stages. Actual and potential evapotranspiration, transpiration, and soil evaporation are obtained in the model by numerical operations on a potential evapotranspiration/potential soil evaporation array obtained by empirical formulae or pan data, and a modified crop coefficient. Soil water status is monitored in the model by taking into account the balance of irrigation, drainage, precipitation, soil water storage and evapotranspiration. Phenological data is computed by a simple numerical formula utilizing maximum and minimum temperatures during the season. Good agreement was found in comparing predicted versus actual heading date for four varieties over four different years. A field study was carried out to aid in model calibration and testing. A continuous variable plot design, with two replications of each of five spring wheat varieties (two soft whit spring wheats and three hard red spring wheats)\u3e This allowed a large number of data points to be measured that related yield to many water levels within the soil. Although this design leads to difficulties in classical statistical analysis, it was shown to be especially useful in calibration of a model of the type shown herein

    Genetic support for the dual nature of attention deficit hyperactivity disorder: substantial genetic overlap between the inattentive and hyperactive-impulsive components

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    Objective Attention deficit hyperactivity disorder (ADHD) is a common, complex and highly heritable disorder, characterised by inattentive, impulsive and overactive behaviour. Evidence for the heritability of ADHD measures in twin population samples has come from the analysis of total scores that combine inattentive and hyperactive–impulsive symptoms subscales. This study investigated, in a community sample, the aetiology of ADHD-like traits and the aetiological overlap between the two dimensions that define the ADHD disorder. Materials and Methods Parents of 6,222 approximately 8-year-old twin pairs from the Twins Early Development Study (TEDS) population sample completed the two subscales of the Conners’ 18-item DSMIV checklist, a screening instrument for ADHD symptoms. Results Both subscales were highly heritable (hyperactive–impulsive: 88%; inattentive: 79%). Bivariate genetic modelling indicated substantial genetic overlap between the two components; however, there were significant independent genetic effects. Conclusions These findings suggest that many genes associated with the hyperactivity–impulsivity dimension will also be associated with the inattentive dimension but that there is significant genetic heterogeneity as well. These results provide genetic support for combining the two behavioural dimensions that define ADHD, but also suggest that some symptom-specific genes will also be identified
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