900 research outputs found

    On the misidentification of chalcid (Hymenoptera: Chalcidoidea) parasitoids of the cabbage seedpod weevil (Coleoptera: Curculionidae) in North America

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    Previous identifications in North America of Trichomalus perfectus (Walker, 1835) and Mesopolobus morys (Walker, 1848) (Chalcidoidea: Pteromalidae), the principal chalcid parasitoids of the cabbage seedpod weevil (Ceutorhynchus obstrictus Marsham, 1802) in Europe, are shown to be misidentifications of Trichomalus lucidus (Walker, 1835) and Mesopolobus (Xenocrepis) moryoides sp. nov., respectively. Necremnus duplicatus Gahan, 1941 (Chalcidoidea: Eulophidae) is synonymized formally under Necremnus tidius (Walker, 1839) syn. nov., confirming a previous, tentative synonymy. Both sexes of N. tidius, M. moryoides, and T. lucidus are illustrated and compared with those of similar species using macrophotography and scanning electron microphotography. Hypotheses are offered to explain why the principal chalcid parasitoids of the cabbage seedpod weevil differ between North America and Europe and how the three treated species came to be in North Americ

    Review of the species of Trichomalus (Chalcidoidea: Pteromalidae) associated with Ceutorhynchus (Coleoptera: Curculionidae) host species of European origin

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    Six species of Trichomalus Thomson were reared as parasitoids of Ceutorhynchinae hosts in Europe during surveys in 2000-2004. Trichomalus rusticus (Walker) is treated as a valid species, resurrected from synonymy under T. lucidus (Walker), and T. lyttus (Walker) is transferred from synonymy under T. lucidus and newly placed in synonymy with T. rusticus. Illustrated keys to females and males are given to differentiate the six species (T. bracteatus (Walker), T. campestris (Walker), T. gynetelus (Walker), T. lucidus, T. perfectus (Walker), and T. rusticus) except for males of T. bracteatus and T. gynetelus. A lectotype female is designated for T. rusticus. Trichomalus campestris is newly recorded as a parasitoid of Ceutorhynchus cardariae Korotyaev. Implications of the host-parasitoid associations recovered by the surveys are discussed relative to introduction of species to North America for classical biological contro

    Elastic moduli of model random three-dimensional closed-cell cellular solids

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    Most cellular solids are random materials, while practically all theoretical results are for periodic models. To be able to generate theoretical results for random models, the finite element method (FEM) was used to study the elastic properties of solids with a closed-cell cellular structure. We have computed the density (Ļ\rho) and microstructure dependence of the Young's modulus (EE) and Poisson's ratio (PR) for several different isotropic random models based on Voronoi tessellations and level-cut Gaussian random fields. The effect of partially open cells is also considered. The results, which are best described by a power law EāˆĻnE\propto\rho^n (1<n<21 < n <2), show the influence of randomness and isotropy on the properties of closed-cell cellular materials, and are found to be in good agreement with experimental data.Comment: 13 pages, 13 figure

    Efficient Recursion Method for Inverting Overlap Matrix

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    A new O(N) algorithm based on a recursion method, in which the computational effort is proportional to the number of atoms N, is presented for calculating the inverse of an overlap matrix which is needed in electronic structure calculations with the the non-orthogonal localized basis set. This efficient inverting method can be incorporated in several O(N) methods for diagonalization of a generalized secular equation. By studying convergence properties of the 1-norm of an error matrix for diamond and fcc Al, this method is compared to three other O(N) methods (the divide method, Taylor expansion method, and Hotelling's method) with regard to computational accuracy and efficiency within the density functional theory. The test calculations show that the new method is about one-hundred times faster than the divide method in computational time to achieve the same convergence for both diamond and fcc Al, while the Taylor expansion method and Hotelling's method suffer from numerical instabilities in most cases.Comment: 17 pages and 4 figure

    Capability, opportunity, and motivation to enact hygienic practices in the early stages of the COVIDā€19 outbreak in the United Kingdom

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    Objectives The COVIDā€19 pandemic is one of the greatest global health threats facing humanity in recent memory. This study aimed to explore influences on hygienic practices, a set of key transmission behaviours, in relation to the Capability, Opportunity, Motivationā€Behaviour (COMā€B) model of behaviour change (Michie et al., 2011). Design Data from the first wave of a longitudinal survey study were used, launched in the early stages of the UK COVIDā€19 pandemic. Methods Participants were 2025 adults aged 18 and older, representative of the UK population, recruited by a survey company from a panel of research participants. Participants selfā€reported motivation, capability, and opportunity to enact hygienic practices during the COVIDā€19 outbreak. Results Using regression models, we found that all three COMā€B components significantly predicted good hygienic practices, with motivation having the greatest influence on behaviour. Breaking this down further, the subscales psychological capability, social opportunity, and reflective motivation positively influenced behaviour. Reflective motivation was largely driving behaviour, with those highest in reflective motivation scoring 51% more on the measure of hygienic practices compared with those with the lowest scores. Conclusions Our findings have clear implications for the design of behaviour change interventions to promote hygienic practices. Interventions should focus on increasing and maintaining motivation to act and include elements that promote and maintain social support and knowledge of COVIDā€19 transmission. Groups in particular need of targeting for interventions to increase hygienic practices are males and those living in cities and suburbs

    HST hot Jupiter transmission spectral survey: detection of water in HAT-P-1b from WFC3 near-IR spatial scan observations

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society Ā©: 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We present Hubble Space Telescope near-infrared transmission spectroscopy of the transiting hot-Jupiter HAT-P-1b. We observed one transit with Wide Field Camera 3 using the G141 low-resolution grism to cover the wavelength range 1.087ā€“1.678ā€‰Ī¼m. These time series observations were taken with the newly available spatial-scan mode that increases the duty cycle by nearly a factor of 2, thus improving the resulting photometric precision of the data. We measure a planet-to-star radius ratio of Rp/R* = 0.117 09 Ā± 0.000 38 in the white light curve with the centre of transit occurring at 245 6114.345 Ā± 0.000 133 (JD). We achieve S/N levels per exposure of 1840 (0.061ā€‰perā€‰cent) at a resolution of Ī”Ī» = 19.2 nm (R āˆ¼ 70) in the 1.1173ā€“1.6549ā€‰Ī¼m spectral region, providing the precision necessary to probe the transmission spectrum of the planet at close to the resolution limit of the instrument. We compute the transmission spectrum using both single target and differential photometry with similar results. The resultant transmission spectrum shows a significant absorption above the 5Ļƒ level matching the 1.4ā€‰Ī¼m water absorption band. In solar composition models, the water absorption is sensitive to the āˆ¼1 m bar pressure levels at the terminator. The detected absorption agrees with that predicted by a 1000ā€‰K isothermal model, as well as with that predicted by a planetary-averaged temperature model.Science & Technology Facilities Council (STFC)Space Telescope Science Institut

    Anxiety, depression, traumatic stress, and COVID-19 related anxiety in the UK general population during the COVID-19 pandemic

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    Background The COVID-19 pandemic has created an unprecedented global crisis necessitating drastic changes to living conditions, social life, personal freedom and economic activity. No study has yet examined the presence of psychiatric symptoms in the UK population in similar conditions. Aims We investigated the prevalence of COVID-19 related anxiety, generalised anxiety, depression and trauma symptoms in a representative sample of the UK population during an early phase of the pandemic, and estimated associations with variables likely to influence these symptoms. Method Between March 23rd and March 28th 2020, a quota sample of 2025 UK adults 18 years and older, stratified by age, sex and household income, was recruited by online survey company Qualtrics. Participants completed measures of depression (PHQ9), generalised anxiety (GAD7), and trauma symptoms relating to the pandemic (ITQ). Bivariate and multivariate associations were calculated for age, gender, rural vs urban environment, presence of children in the household, income, loss of income, pre-existing health conditions in self and someone close, infection in self and someone close, and perceived risk of infection over the next month. Results Higher levels of anxiety, depression and trauma symptoms were reported compared to previous population studies, but not dramatically so. Meeting the criteria for either anxiety or depression, and trauma symptoms was predicted by young age, presence of children in the home, and high estimates of personal risk. Anxiety and depression symptoms were also predicted by low income, loss of income, and pre-existing health conditions in self and other. Specific anxiety about COVID-19 was greater in older participants. Conclusions The UK population, especially older citizens, were largely resilient in the early stages of the pandemic. However, several specific COVID-related variables are associated with psychological distress: particularly having children at home, loss of income because of the pandemic, as well as having a pre-existing health condition, exposure to the virus and high estimates of personal risk. Further similar surveys, particularly of those with children at home, are required as the pandemic progresses

    Influence of OATP1B1 Function on the Disposition of Sorafenib-Ī²-D-Glucuronide

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    The oral multikinase inhibitor sorafenib undergoes extensive UGT1A9-mediated formation of sorafenib-Ī²-D-glucuronide (SG). Using transporter-deficient mouse models, it was previously established that SG can be extruded into bile by ABCC2 or follow a liver-to-blood shuttling loop via ABCC3-mediated efflux into the systemic circulation, and subsequent uptake in neighboring hepatocytes by OATP1B-type transporters. Here we evaluated the possibility that this unusual process, called hepatocyte hopping, is also operational in humans and can be modulated through pharmacological inhibition. We found that SG transport by OATP1B1 or murine Oatp1b2 was effectively inhibited by rifampin, and that this agent can significantly increase plasma levels of SG in wildtype mice, but not in Oatp1b2-deficient animals. In human subjects receiving sorafenib, rifampin acutely increased the systemic exposure to SG. Our study emphasizes the need to consider hepatic handling of xenobiotic glucuronides in the design of drug-drug interaction studies of agents that undergo extensive phase II conjugation

    Processing of aluminum-graphite particulate metal matrix composites by advanced shear technology

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    Copyright @ 2009 ASM International. This paper was published in Journal of Materials Engineering and Performance 18(9) and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.To extend the possibilities of using aluminum/graphite composites as structural materials, a novel process is developed. The conventional methods often produce agglomerated structures exhibiting lower strength and ductility. To overcome the cohesive force of the agglomerates, a melt conditioned high-pressure die casting (MC-HPDC) process innovatively adapts the well-established, high-shear dispersive mixing action of a twin screw mechanism. The distribution of particles and properties of composites are quantitatively evaluated. The adopted rheo process significantly improved the distribution of the reinforcement in the matrix with a strong interfacial bond between the two. A good combination of improved ultimate tensile strength (UTS) and tensile elongation (e) is obtained compared with composites produced by conventional processes.EPSR
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