1,848 research outputs found

    STONE TOOL-USE EXPERIMENTS TO DETERMINE THE FUNCTION OF GRINDING STONES AND DENTICULATE SICKLES

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    Within a broader study of early Chinese agriculture, stone tool-use experiments were undertaken to document usewear on sandstone and tuff implements used to process Quercus acorns, Avena oats and Setaria millet. In other experiments, we examined usewear on denticulate slate sickles used to harvest Quercus acorns, Poaceae grass and Typha reeds. Results support other studies that indicate different patterns of abrasive smoothing, striation formation and polish development together provide a basis for distinguishing some of these tasks. This research is aimed to establish a database for functional analysis of grinding stones and sickles from the early Neolithic Peiligang culture. Controlled experiments are required to identify critical variables (e.g. silica in husks) that affect usewear patterns

    Superconducting tantalum disulfide nanotapes; growth, structure and stoichiometry

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    Superconducting tantalum disulfide nanowires have been synthesised by surface-assisted chemical vapour transport (SACVT) methods and their crystal structure, morphology and stoichiometry studied by powder X-ray diffraction (PXD), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and nanodiffraction. The evolution of morphology, stoichiometry and structure of materials grown by SACVT methods in the Ta-S system with reaction temperature was investigated systematically. High-aspect-ratio, superconducting disulfide nanowires are produced at intermediate reaction temperatures (650 degrees C). The superconducting wires are single crystalline, adopt the 2H polytypic structure (hexagonal space group P6(3)/mmc: a = 3.32(2) angstrom, c = 12.159(2) angstrom; c/a = 3.66) and grow in the <2<(1)over bar>(1) over bar0> direction. The nanowires are of rectangular cross-section forming nanotapes composed of bundles of much smaller fibres that grow cooperatively. At lower reaction temperatures nanowires close to a composition of TaS3 are produced whereas elevated temperatures yield platelets of 1T TaS2

    Effects of heat exposure and volumetric compression on Poisson's ratios, Young's moduli and polymeric composition during thermo-mechanical conversion of auxetic open cell polyurethane foam

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    The effects of thermo-mechanical auxetic foam conversion parameters on the Young's modulus and Poisson's ratio of open-cell polyurethane foam are related to changes in chemical bonding and cell structure. Applied volumetric compression, conversion temperature and duration are reported on foam Young's modulus, Poisson's ratio and structural stability. Fourier transform infrared spectral analysis on samples converted at and above 160°C strongly indicates a hydrogen bond interaction increase in urea groups (C=O---H-N) and an increase in hydrogen bonding population. Spectral changes inferred soft segment degradation following extensive heat exposure (200°C, 180 minutes), specifically a shift and intensity change in CH2 and C-O-C polyol bands and a broad baseline increase between 3600 and 2400 cm-1. These changes are linked to: i) resistance to dimensional recovery over time and during re-heating, ii) Poisson's ratio becoming negative, then zero in tension or marginally positive in compression, iii) Young's Modulus reducing then increasing, iv) mass loss, evidenced by thermogravimetric analysis increasing from 150°C. The minimum mean values of Poisson's ratio of ~-0.2 (to 10% compression/tension) are comparable to other studies. All samples that retain their imposed compression over time are isotropic, with near constant Young's moduli and Poisson's ratio (to 10 % compression/tension)

    Phylogenomic exploration of the relationships between strains of Mycobacterium avium subspecies paratuberculosis.

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    BACKGROUND: Mycobacterium avium subspecies paratuberculosis (Map) is an infectious enteric pathogen that causes Johne's disease in livestock. Determining genetic diversity is prerequisite to understanding the epidemiology and biology of Map. We performed the first whole genome sequencing (WGS) of 141 global Map isolates that encompass the main molecular strain types currently reported. We investigated the phylogeny of the Map strains, the diversity of the genome and the limitations of commonly used genotyping methods. RESULTS: Single nucleotide polymorphism (SNP) and phylogenetic analyses confirmed two major lineages concordant with the former Type S and Type C designations. The Type I and Type III strain groups are subtypes of Type S, and Type B strains are a subtype of Type C and not restricted to Bison species. We found that the genome-wide SNPs detected provided greater resolution between isolates than currently employed genotyping methods. Furthermore, the SNP used for IS1311 typing is not informative, as it is likely to have occurred after Type S and C strains diverged and does not assign all strains to the correct lineage. Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR) differentiates Type S from Type C but provides limited resolution between isolates within these lineages and the polymorphisms detected do not necessarily accurately reflect the phylogenetic relationships between strains. WGS of passaged strains and coalescent analysis of the collection revealed a very high level of genetic stability, with the substitution rate estimated to be less than 0.5 SNPs per genome per year. CONCLUSIONS: This study clarifies the phylogenetic relationships between the previously described Map strain groups, and highlights the limitations of current genotyping techniques. Map isolates exhibit restricted genetic diversity and a substitution rate consistent with a monomorphic pathogen. WGS provides the ultimate level of resolution for differentiation between strains. However, WGS alone will not be sufficient for tracing and tracking Map infections, yet importantly it can provide a phylogenetic context for affirming epidemiological connections

    Children and older adults exhibit distinct sub-optimal cost-benefit functions when preparing to move their eyes and hands

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    "© 2015 Gonzalez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited"Numerous activities require an individual to respond quickly to the correct stimulus. The provision of advance information allows response priming but heightened responses can cause errors (responding too early or reacting to the wrong stimulus). Thus, a balance is required between the online cognitive mechanisms (inhibitory and anticipatory) used to prepare and execute a motor response at the appropriate time. We investigated the use of advance information in 71 participants across four different age groups: (i) children, (ii) young adults, (iii) middle-aged adults, and (iv) older adults. We implemented 'cued' and 'non-cued' conditions to assess age-related changes in saccadic and touch responses to targets in three movement conditions: (a) Eyes only; (b) Hands only; (c) Eyes and Hand. Children made less saccade errors compared to young adults, but they also exhibited longer response times in cued versus non-cued conditions. In contrast, older adults showed faster responses in cued conditions but exhibited more errors. The results indicate that young adults (18 -25 years) achieve an optimal balance between anticipation and execution. In contrast, children show benefits (few errors) and costs (slow responses) of good inhibition when preparing a motor response based on advance information; whilst older adults show the benefits and costs associated with a prospective response strategy (i.e., good anticipation)

    Maxwell-Chern-Simons Vortices and Holographic Superconductors

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    We investigate probe limit vortex solutions of a charged scalar field in Einstein-Maxwell theory in 3+1 dimensions, for an asymptotically AdS Schwarzschild black hole metric with the addition of an axionic coupling to the Maxwell field. We show that the inclusion of such a term, together with a suitable potential for the axion field, can induce an effective Chern-Simons term on the 2+1 dimensional boundary. We obtain numerical solutions of the equations of motion and find Maxwell-Chern-Simons like magnetic vortex configurations, where the magnetic field profile varies with the size of the effective Chern-Simons coupling. The axion field has a non-trivial profile inside the AdS bulk but does not condense at spatial infinity.Comment: 17 pages, 5 figures, version accepted for publication in JHE

    Walks4work: Rationale and study design to investigate walking at lunchtime in the workplace setting

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    Background: Following recruitment of a private sector company, an 8week lunchtime walking intervention was implemented to examine the effect of the intervention on modifiable cardiovascular disease risk factors, and further to see if walking environment had any further effect on the cardiovascular disease risk factors. Methods. For phase 1 of the study participants were divided into three groups, two lunchtime walking intervention groups to walk around either an urban or natural environment twice a week during their lunch break over an 8week period. The third group was a waiting-list control who would be invited to join the walking groups after phase 1. In phase 2 all participants were encouraged to walk during their lunch break on self-selecting routes. Health checks were completed at baseline, end of phase 1 and end of phase 2 in order to measure the impact of the intervention on cardiovascular disease risk. The primary outcome variables of heart rate and heart rate variability were measured to assess autonomic function associated with cardiovascular disease. Secondary outcome variables (Body mass index, blood pressure, fitness, autonomic response to a stressor) related to cardiovascular disease were also measured. The efficacy of the intervention in increasing physical activity was objectively monitored throughout the 8-weeks using an accelerometer device. Discussion. The results of this study will help in developing interventions with low researcher input with high participant output that may be implemented in the workplace. If effective, this study will highlight the contribution that natural environments can make in the reduction of modifiable cardiovascular disease risk factors within the workplace. © 2012 Brown et al.; licensee BioMed Central Ltd

    A novel high mobility group box 1 neutralizing chimeric antibody attenuates drug-induced liver injury and postinjury inflammation in mice

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    Acetaminophen (APAP) overdoses are of major clinical concern. Growing evidence underlines a pathogenic contribution of sterile postinjury inflammation in APAP‐induced acute liver injury (APAP‐ALI) and justifies development of anti‐inflammatory therapies with therapeutic efficacy beyond the therapeutic window of the only current treatment option, N‐acetylcysteine (NAC). The inflammatory mediator, high mobility group box 1 (HMGB1), is a key regulator of a range of liver injury conditions and is elevated in clinical and preclinical APAP‐ALI. The anti‐HMGB1 antibody (m2G7) is therapeutically beneficial in multiple inflammatory conditions, and anti‐HMGB1 polyclonal antibody treatment improves survival in a model of APAP‐ALI. Herein, we developed and investigated the therapeutic efficacy of a partly humanized anti‐HMGB1 monoclonal antibody (mAb; h2G7) and identified its mechanism of action in preclinical APAP‐ALI. The mouse anti‐HMGB1 mAb (m2G7) was partly humanized (h2G7) by merging variable domains of m2G7 with human antibody‐Fc backbones. Effector function‐deficient variants of h2G7 were assessed in comparison with h2G7 in vitro and in preclinical APAP‐ALI. h2G7 retained identical antigen specificity and comparable affinity as m2G7. 2G7 treatments significantly attenuated APAP‐induced serum elevations of alanine aminotransferase and microRNA‐122 and completely abrogated markers of APAP‐induced inflammation (tumor necrosis factor, monocyte chemoattractant protein 1, and chemokine [C‐X‐C motif] ligand 1) with prolonged therapeutic efficacy as compared to NAC. Removal of complement and/or Fc receptor binding did not affect h2G7 efficacy. Conclusion: This is the first report describing the generation of a partly humanized HMGB1‐neutralizing antibody with validated therapeutic efficacy and with a prolonged therapeutic window, as compared to NAC, in APAP‐ALI. The therapeutic effect was mediated by HMGB1 neutralization and attenuation of postinjury inflammation. These results represent important progress toward clinical implementation of HMGB1‐specific therapy as a means to treat APAP‐ALI and other inflammatory conditions. (Hepatology 2016;64:1699‐1710)

    Changing gender roles and attitudes and their implications for well-being around the new millennium

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    <b>Purpose</b><p></p> Given evidence that gender role attitudes (GRAs) and actual gender roles impact on well-being, we examine associations between GRAs, three roles (marital status, household chore division, couple employment) and psychological distress in working-age men and women. We investigate time-trends reflecting broader social and economic changes, by focusing on three age groups at two dates.<p></p> <b>Methods</b><p></p> We used British Household Panel Survey data from 20- to 64-year-olds in heterosexual couple households in 1991 (N = 5,302) and 2007 (N = 6,621). We examined: levels of traditional GRAs according to gender, age, date, household and employment roles; associations which GRAs and roles had with psychological distress (measured via the GHQ-12); whether psychological distress increased when GRAs conflicted with actual roles; and whether any of these associations differed according to gender, age or date.<p></p> <b>Results</b><p></p> Gender traditionalism was lower among women, younger people, those participating in 2007 and in ‘less traditional’ relationships and households. Psychological distress was higher among those with more traditional GRAs and, particularly among men, for those not employed, and there was some evidence of different patterns of association according to age-group. There was limited evidence, among women only, of increased psychological distress when GRAs and actual roles conflicted and/or reductions when GRAs and roles agreed, particularly in respect of household chores and paid employment.<p></p> <b>Conclusions</b><p></p> Although some aspects of gender roles and attitudes (traditionalism and paid employment) are associated with well-being, others (marital status and household chores), and attitude-role consistency, may have little impact on the well-being of contemporary UK adults.<p></p&gt
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