3,747 research outputs found

    A worldwide correlation of lactase persistence phenotype and genotypes

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    Background: The ability of adult humans to digest the milk sugar lactose - lactase persistence - is a dominant Mendelian trait that has been a subject of extensive genetic, medical and evolutionary research. Lactase persistence is common in people of European ancestry as well as some African, Middle Eastern and Southern Asian groups, but is rare or absent elsewhere in the world. The recent identification of independent nucleotide changes that are strongly associated with lactase persistence in different populations worldwide has led to the possibility of genetic tests for the trait. However, it is highly unlikely that all lactase persistence-associated variants are known. Using an extensive database of lactase persistence phenotype frequencies, together with information on how those data were collected and data on the frequencies of lactase persistence variants, we present a global summary of the extent to which current genetic knowledge can explain lactase persistence phenotype frequency. Results: We used surface interpolation of Old World lactase persistence genotype and phenotype frequency estimates obtained from all available literature and perform a comparison between predicted and observed trait frequencies in continuous space. By accommodating additional data on sample numbers and known false negative and false positive rates for the various lactase persistence phenotype tests (blood glucose and breath hydrogen), we also apply a Monte Carlo method to estimate the probability that known lactase persistence-associated allele frequencies can explain observed trait frequencies in different regions. Conclusion: Lactase persistence genotype data is currently insufficient to explain lactase persistence phenotype frequency in much of western and southern Africa, southeastern Europe, the Middle East and parts of central and southern Asia. We suggest that further studies of genetic variation in these regions should reveal additional nucleotide variants that are associated with lactase persistence

    Psychopathology in police custody: The role of importation, deprivation and interaction models

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    People experiencing mental illness are over-represented among police cell detainees, however limited work has sought to investigate the occurrence of psychopathology in police custody. The present study sought to examine the predictive power of personal factors (e.g., history of psychiatric hospitalisation), situational factors (e.g., police cell conditions), and their interactive effects to explain the occurrence of psychopathology in police custody. A total of 150 detainees were recruited from two metropolitan police stations in Melbourne, Australia. Personal factors were significantly associated with psychiatric symptomatology, with situational factors and interaction terms yielding no association. Detainees with preexisting vulnerabilities and those unsatisfied with police cell conditions demonstrated the highest levels of psychopathology. While all detainees experience some difficulties in police cells, it is those with pre-existing vulnerabilities that suffer the most. This may be due to the exacerbation of vulnerabilities by police cell conditions. The implications of these findings for provision of health care services in police cells are discussed

    Effects of rundown in soil hydraulic condition on crop productivity in south-eastern Queensland - a simulation study

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    Declining soil organic matter levels because of cropping have been shown to reduce crop growth and yield, but the effects of changing infiltration and soil hydraulic properties on crop productivity have not been widely evaluated. Cropping systems in south-eastern Queensland have, in the past, involved intense tillage, trafficking with heavy machinery, and changed organic matter cycling, affecting soil aggregation, permeability, water-holding characteristics, and organic matter. The aim of this paper is to determine how important infiltration and soil hydraulic condition has been to the water balance, crop growth, and yield in the past, and may be in the future if management is not changed. Change in physical and chemical condition of the 5 most commonly cropped soils in south-east Queensland (Sodosols, Vertosols with ≤55% clay, Vertosols with >55% clay, Red Ferrosols and Red Chromosols/Kandosols) was measured over 0–70 years of cropping and estimated up to 200 years. The APSIM model was used to predict effects of changing soil condition in a rain-fed, fertilised, wheat-summer fallow cropping system with intense tillage. Decline in infiltration, restricted internal redistribution of water, and increased evaporation reduced water supply to the crop, causing simulated yield to decline by 29, 38, 25, 17, and 13% for the 5 soils, respectively, after 50 years of cropping. Gross margin declined at a faster rate, falling by 36, 50, 40, 20, and 21%, respectively after 50 years because of increasing fertiliser requirement to compensate for declining soil fertility. Crop productivity on most soils continued to steadily decline as period of cropping increased to 200 years. To arrest or reverse this downward trend, it is likely that substantial changes to current cropping systems will be needed, including reducing tillage and trafficking, and improving organic matter levels

    Simulating infiltration and the water balance in cropping systems with APSIM-SWIM

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    We test APSIM-SWIM's ability to simulate infiltration and interactions between the soil water balance and grain crop growth using soil hydraulic properties derived from independent, point measurements. APSIMSWIM is a continuous soil-crop model that simulates infiltration, surface crusting, and soil condition in more detail than most other soil-crop models. Runoff, soil water, and crop growth information measured at sites in southern Queensland was used to test the model. Parameter values were derived directly from soil hydraulic properties measured using rainfall simulators, disc permeameters and ponded rings, and pressure plate apparatus. In general, APSIM-SWIM simulated infiltration, runoff, soil water and the water balance, and yield as accurately and reliably as other soil crop models, indicating the model is suitable for evaluating effects of infiltration and soil-water relations on crop growth. Increased model detail did not hinder application, instead improving parameter transferability and utility, but improved methods of characterising crusting, soil hydraulic conductivity, and macroporosity under field conditions would improve ease of application, prediction accuracy, and reliability of the model. Model utility and accuracy would benefit from improved representation of temporal variation in soil condition, including effects of tillage and consolidation on soil condition and bypass flow in cracks

    Correlates of criminal victimisation among police cell detainees in Victoria, Australia

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    People with mental illness are more likely to be crime victims than others; however, little is known about the relationship between offending and victimisation among mentally ill offenders. This study investigated the rates and types of victimisation among people detained in police cells (N = 764), with and without histories of mental illness. Those with mental disorders were 1.56 times (95% CI = 1.11–2.17) more likely to be victims of violent crimes than other detainees. Some subgroups of people with mental disorders were not over-represented as victims, raising the possibility that they were less inclined to report certain types of crimes. Implications are discussed with reference to police practice

    Bohm's interpretation and maximally entangled states

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    Several no-go theorems showed the incompatibility between the locality assumption and quantum correlations obtained from maximally entangled spin states. We analyze these no-go theorems in the framework of Bohm's interpretation. The mechanism by which non-local correlations appear during the results of measurements performed on distant parts of entangled systems is explicitly put into evidence in terms of Bohmian trajectories. It is shown that a GHZ like contradiction of the type+1=-1 occurs for well-chosen initial positions of the Bohmian trajectories and that it is this essential non-classical feature that makes it possible to violate the locality condition.Comment: 18 page

    General solutions of the Wess-Zumino consistency condition for the Weyl anomalies

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    The general solutions of the Wess-Zumino consistency condition for the conformal (or Weyl, or trace) anomalies are derived. The solutions are obtained, in arbitrary dimensions, by explicitly computing the cohomology of the corresponding Becchi-Rouet-Stora-Tyutin differential in the space of integrated local functions at ghost number unity. This provides a purely algebraic, regularization-independent classification of the Weyl anomalies in arbitrary dimensions. The so-called type-A anomaly is shown to satisfy a non-trivial descent of equations, similarly to the non-Abelian chiral anomaly in Yang-Mills theory.Comment: 9 pages. RevTeX fil

    Capillary electrophoresis-mass spectrometry characterisation of secondary metabolites from the antihyperglycaemic plant Genista tenera

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    Genista tenera is endemic to the Portuguese island of Madeira, where an infusion of the aerial parts of the plant is used in folk medicine as an antidiabetic agent. Consequently the medicinal properties of the secondary metabolites of this plant have been the subject of an ongoing study. A recently reported LC-MS method using a 100 min separation allowed identification of five flavonoid components in an extract of the aerial parts of this plant. In order to obtain additional information on the range and complexity of the plant’s secondary metabolite components a CE-MS method has been developed and applied for the analysis of an extract of G. tenera. Twenty-six different components are distinguished in an analysis time of only 10 min. Results demonstrate that CE-MS/MS rapidly generates data complementary to those obtainable by LC-MS/MS and is particularly suited to the analysis of plant metabolites where concentration is not limiting.BBSRC, University of York, Treaty of Windsor Anglo-Portuguese joint research programme, Thermo Electron, Analytical Chemistry Trust Fund, Royal Society of Chemistry Analytical Division, Engineering and Physical Sciences Research Council (EPSRC)info:eu-repo/semantics/publishedVersio

    Steady and Stable: Numerical Investigations of Nonlinear Partial Differential Equations

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    Excerpt: Mathematics is a language which can describe patterns in everyday life as well as abstract concepts existing only in our minds. Patterns exist in data, functions, and sets constructed around a common theme, but the most tangible patterns are visual. Visual demonstrations can help undergraduate students connect to abstract concepts in advanced mathematical courses. The study of partial differential equations, in particular, benefits from numerical analysis and simulation

    Bragg spectroscopy with an accelerating Bose-Einstein condensate

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    We present the results of Bragg spectroscopy performed on an accelerating Bose-Einstein condensate. The Bose condensate undergoes circular micro-motion in a magnetic TOP trap and the effect of this motion on the Bragg spectrum is analyzed. A simple frequency modulation model is used to interpret the observed complex structure, and broadening effects are considered using numerical solutions to the Gross-Pitaevskii equation.Comment: 5 pages, 3 figures, to appear in PRA. Minor changes to text and fig
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