3,395 research outputs found

    Modeling current and potential distributions of mammal species using presence?only data: a case study on British deer

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    Aim: Decisions on wildlife conservation, management, and epidemiological risk are best based on robust evidence. The continual improvement of species distributions, such that they can be relied upon in decision?making, is important. Here we seek to refine aspects of a generic modelling approach and improve the utility of speciesdistribution maps.Location: Great Britain (GB).Methods: We applied a modeling framework based on hierarchical Bayesian species distribution models exploiting opportunistic occurrence records from citizen science datasets to predict both current and potential distributions for each of the six deerspecies known to be present in GB. Using the resulting maps, we performed a simple analysis of the overlap between species to illustrate possible contact, which we interpret as the relative risk of potential disease spread given an introduction.Results: Predicted distribution maps showed good agreement with the broader scale occurrence reported by a recent national deer survey with an average True Skill Statistics and AUC of 0.69 and 0.89, respectively. Aggregation of the maps for all species highlighted regions of central and eastern England as well as parts of Scotlandwhere extensive areas of range overlap could result in interspecific contact with consequences for risk assessments for diseases of deer. However, if populations are allowed to expand to their predicted potential, then areas of overlap, and therefore disease interspecific transmission risk, will become extensive and widespread across all of mainland Britain.Main conclusions: The generic modeling approach outlined performed well across all of the deer species tested, offering a robust and reliable tool through which current and potential animal distributions can be estimated and presented. Our application,intended to inform quantitative risk assessments, demonstrates the practical use of such outputs to generate the valuable evidence required to inform policy decisions on issues such as management strategy

    Dehydrative etherification reactions of glycerol with alcohols catalyzed by recyclable nanoporous aluminosilicates: telescoped routes to glyceryl ethers

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    Catalytic strategies for the efficient transformation of abundant sustainable bioderived molecules, such as glycerol, into higher value more useful products is an important research goal. In this study, we demonstrate that atom efficient dehydrative etherification reactions of glycerol with activated alcohols are effectively catalyzed by nanoporous aluminosilicate materials in dimethylcarbonate (DMC) to produce the corresponding 1-substituted glyceryl ethers in high yield. By carrying out the reaction in acetone, it is possible to capitalize on the ability of these materials to catalyze the corresponding acetalization reaction, allowing for the development of novel, telescoped acetalization-dehydrative etherification reaction sequences to selectively produce protected solketal derivatives. These materials also catalyze the telescoped reaction of glycerol with <i>tert</i>-butanol (TBA) in acetone to produce the corresponding solketal mono <i>tert</i>-butyl ether product in high yield, providing a potential route to convert glycerol directly into a useful and sustainable fuel additive

    Synthesis and reactivity of N-allenyl cyanamides

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    N-Allenyl cyanamides have been accessed via a one-pot deoxycyanamidation–isomerization approach using propargyl alcohol and N-cyano-N-phenyl-p-methylbenzenesulfonamide. The utility of this novel class of allenamide was explored through derivatization, with hydroarylation, hydroamination, and cycloaddition protocols employed to access an array of cyanamide products that would be challenging to access using existing methods

    The effects of secondary oxides on copper-based catalysts for green methanol synthesis

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    © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Catalysts for methanol synthesis from CO 2 and H 2 have been produced by two main methods: co-precipitation and supercritical anti-solvent (SAS) precipitation. These two methods are compared, along with the behaviour of copper supported on Zn, Mg, Mn, and Ce oxides. Although the SAS method produces initially active material with high Cu specific surface area, they appear to be unstable during reaction losing significant amounts of surface area and hence activity. The CuZn catalysts prepared by co-precipitation, however, showed much greater thermal and reactive stability than the other materials. There appeared to be the usual near-linear dependence of activity upon Cu specific area, though the initial performance relationship was different from that post-reaction, after some loss of surface area. The formation of the malachite precursor, as reported before, is important for good activity and stability, whereas if copper oxides are formed during the synthesis and ageing process, then a detrimental effect on these properties is seen

    Multilevel population-based cross-sectional study examining school substance-misuse policy and the use of cannabis, mephedrone and novel psychoactive substances among students aged 11-16 years in schools in Wales

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    Objectives To examine whether young peoples’ risk of cannabis, mephedrone and novel psychoactive substances (NPS) use is associated with school substance-misuse policy. Design A cross-sectional survey of secondary school students combined with a School Environment Questionnaire and independently coded school substance-misuse policies (2015/6). Setting 66 secondary schools in Wales. Participants Students aged 11–16 years (n=18 939). Results The prevalence of lifetime, past 30-day and daily cannabis use was 4.8%, 2.6% and 0.7%, respectively; lifetime prevalence of mephedrone use was 1.1% and NPS use was 1.5%. Across 66 schools, 95.5% (n=63) reported having a substance-misuse policy, 93.9% (n=62) reported having a referral pathway for drug using students, such that we were insufficiently powered to undertake an analysis. We found little evidence of a beneficial association between lifetime cannabis use and involving students in policy development including student council consultation (OR=1.24, 95% CI 0.89 to 1.73), other student consultation (OR=1.42, 95% CI 0.94 to 2.14) or with the use of isolation (OR=0.98, 95% CI 0.67 to 1.43), with similar results for cannabis use in past 30 days, daily and the lifetime use of mephedrone and NPS. The School Environment Questionnaires found that 39.4% (n=26) schools reported no student involvement in policy development, 42.4% (n=28) reported student council consultation, 18.2% (n=12) used other student consultations and 9.7% (n=3) mentioned isolation. The independently coded content of policies found that no school policy recommended abstinence, one mentioned methods on harm minimisation, 16.1% (n=5) policies mentioned student involvement and 9.7% (n=3) mentioned isolation. Conclusions Policy development involving students is widely recommended, but we found no beneficial associations between student involvement in policy development and student drug use. This paper has highlighted the need for further contextual understanding around the policy-development process and how schools manage drug misuse

    Principles for the post-GWAS functional characterisation of risk loci

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    Several challenges lie ahead in assigning functionality to susceptibility SNPs. For example, most effect sizes are small relative to effects seen in monogenic diseases, with per allele odds ratios usually ranging from 1.15 to 1.3. It is unclear whether current molecular biology methods have enough resolution to differentiate such small effects. Our objective here is therefore to provide a set of recommendations to optimize the allocation of effort and resources in order maximize the chances of elucidating the functional contribution of specific loci to the disease phenotype. It has been estimated that 88% of currently identified disease-associated SNP are intronic or intergenic. Thus, in this paper we will focus our attention on the analysis of non-coding variants and outline a hierarchical approach for post-GWAS functional studies

    The effect of sodium species on methanol synthesis and water-gas shift Cu/ZnO catalysts: utilising high purity zincian georgeite

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    The effect of sodium species on the physical and catalytic properties of Cu/ZnO catalysts derived from zincian georgeite has been investigated. Catalysts prepared with <100 ppm to 2.1 wt% Na+, using a supercritical CO2 antisolvent technique, were characterised and tested for the low temperature water–gas shift reaction and also CO2 hydrogenation to methanol. It was found that zincian georgeite catalyst precursor stability was dependent on the Na+ concentration, with the 2.1 wt% Na+-containing sample uncontrollably ageing to malachite and sodium zinc carbonate. Samples with lower Na+ contents (<100–2500 ppm) remained as the amorphous zincian georgeite phase, which on calcination and reduction resulted in similar CuO/Cu particle sizes and Cu surface areas. The aged 2.1 wt% Na+ containing sample, after calcination and reduction, was found to comprise of larger CuO crystallites and a lower Cu surface area. However, calcination of the high Na+ sample immediately after precipitation (before ageing) resulted in a comparable CuO/Cu particle size to the lower (<100–2500 ppm) Na+ containing samples, but with a lower Cu surface area, which indicates that Na+ species block Cu sites. Activity of the catalysts for the water–gas shift reaction and methanol yields in the methanol synthesis reaction correlated with Na+ content, suggesting that Na+ directly poisons the catalyst. In situ XRD analysis showed that the ZnO crystallite size and consequently Cu crystallite size increased dramatically in the presence of water in a syn-gas reaction mixture, showing that stabilisation of nanocrystalline ZnO is required. Sodium species have a moderate effect on ZnO and Cu crystallite growth rate, with lower Na+ content resulting in slightly reduced rates of growth under reaction conditions

    A COMPARISON OF ELECTROMECHANICAL VERSUS PNEUMATIC-CONTROLLED KNEE SIMULATORS FOR THE WEAR PERFORMANCE OF A TOTAL ANKLE ARTHROPLASTY

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    Objectives Implant loosening remains a common cause of total ankle replacement (TAR) revision, and has been associated with wear-mediated osteolysis. Limited pre-clinical studies for TARs have been reported and the variety of experiment settings make it difficult to compare wear rates. Factors such as simulator control mechanism; whether pneumatic or electromechanical, may influence the integrity of the simulator outputs with respect to input profiles. This study compares the wear of a TAR, tested in electromechanical and pneumatic experimental simulators under identical input conditions. Methods Twelve medium BOX® (MatOrtho Ltd) TARs (n=6 for each simulator) were tested in an electromechanical and pneumatic knee simulator (Simulation Solutions, UK) for 3 million cycles (Mc). Standard ‘Leeds’ displacement-controlled inputs were used. Kinematic performance was investigated by comparing the output profiles against the maximum demanded input values. The lubricant used was 25% new-born calf serum and wear was determined gravimetrically. Results There was no significant difference (P=0.66) in wear rate between simulators (electromechanical = 15.96 ± 6.37mm3/Mc; pneumatic = 14.51 ± 5.27mm3/Mc). The electromechanical simulator (3157.06 ± 1.52N) achieved the maximum load (3150N), but the pneumatic simulator was unable to attain the demand (2542.34 ± 86.52N). Maximum AP displacement from the electromechanical simulator was 3.27 ± 0.07mm (3.1mm input), compared to 3.62 ± 0.95mm from the pneumatic simulator. Internal/external rotation angle was 7.97° ± 0.00 (8° input) and 7.24° ± 0.12 from the electromechanical and pneumatic simulators respectively. Both simulators achieved the demanded flexion angle (±15°). Conclusions The outputs from the electromechanical simulator followed the input profiles more closely than the pneumatic simulator. Despite these differences, there was no significant influence on wear rate. The variation in kinematics between simulators was not sufficient to significantly change the tribological conditions of the TAR. The authors recommend the use of electromechanical simulators for future studies where more demanding and adverse conditions may be applied

    Supercritical antisolvent precipitation of amorphous copper–zinc georgeite and acetate precursors for the preparation of ambient‐pressure water‐gas‐shift copper/zinc oxide catalysts

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    A series of copper-zinc acetate and zincian georgeite precursors have been produced by supercritical CO2 anti-solvent (SAS) precipitation as precursors to Cu/ZnO catalysts for the water gas shift (WGS) reaction. The amorphous materials were prepared by varying the water/ethanol volumetric ratio in the initial metal acetate solutions. Water addition promoted georgeite formation at the expense of mixed metal acetates, which are formed in the absence of the water co-solvent. Optimum SAS precipitation occurs without water to give high surface areas, whilst a high water content gives inferior surface areas and copper-zinc segregation. Calcination of the acetates is exothermic, producing a mixture of metal oxides with high crystallinity. However, thermal decomposition of zincian georgeite resulted in highly dispersed CuO and ZnO crystallites with poor structural order. The georgeite-derived catalysts give superior WGS performance in comparison to the acetate-derived catalysts, which is attributed to enhanced copper-zinc interactions that originate from the precursor

    Towards discovery of gravitationally lensed explosive transients: the brightest galaxies in massive galaxy clusters from Planck-SZ2

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    We combine the Planck-SZ2 galaxy cluster catalogue with near-infrared photometry of galaxies from the VISTA Hemisphere Survey to identify candidate brightest cluster galaxies (BCGs) in 306 massive clusters in the Southern skies at redshifts of z>0.1z>0.1. We find that 91% of these clusters have at least one candidate BCG within the 95% confidence interval on the cluster centers quoted by the Planck collaboration, providing reassurance that our analyses are statistically compatible, and find 92% to be reasonable candidates following a manual inspection. We make our catalog publicly available to assist colleagues interested in multi-wavelength studies of cluster cores, and the search for gravitationally lensed explosive transients in upcoming surveys including the Legacy Survey of Space and Time by the Vera C. Rubin Observatory.Comment: Published in RNAAS in March 2023. 3 pages, 1 figur
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