2,125 research outputs found

    Extremely Red Objects in Two Quasar Fields at z ~ 1.5

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    We present an investigation of the properties and environments of bright extremely red objects (EROs) found in the fields of the quasars TXS 0145+386 and 4C 15.55, both at z ~ 1.4. There is marginal evidence from Chandra ACIS imaging for hot cluster gas with a luminosity of a few 10^44 ergs/s in the field of 4C 15.55. The TXS 0145+386 field has an upper limit at a similar value, but it also clearly shows an overdensity of faint galaxies. None of the EROs are detected as X-ray sources. For two of the EROs that have spectral-energy distributions and rest-frame near-UV spectra that show that they are strongly dominated by old stellar populations, we determine radial-surface-brightness profiles from adaptive-optics images. Both of these galaxies are best fit by profiles close to exponentials, plus a compact nucleus comprising ~30% of the total light in one case and 8% in the other. Neither is well fit by an r^1/4-law profile. This apparent evidence for the formation of massive ~2 X 10^11 disks of old stars in the early universe indicates that at least some galaxies formed essentially monolithically, with high star-formation rates sustained over a few 10^8 years, and without the aid of major mergers.Comment: 25 pages, 13 figures, accepted to Ap

    Examining the symptom-level specificity of negative problem orientation in a clinical sample

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    This article was originally published in Cognitive Behaviour Therapy. The version of record can be found here: http://www.tandfonline.com/doi/abs/10.1080/16506073.2014.987314Given the equivocal state of the literature as to the symptom-level specificity of the cognitive variable labeled negative problem orientation (NPO), we targeted NPO–symptom relations. A clinical sample (N = 132) of adults diagnosed with an anxiety disorder, mood disorder, or obsessive-compulsive disorder completed self-reports of NPO and symptom types (worry, depression, obsessive-compulsive, panic, and social anxiety). Symptom-level specificity was examined using a combination of zero-order and regression analyses that controlled for the other assessed symptoms. Results were that NPO shared small to moderate correlations with the symptoms. Regression results indicated that NPO only shared unique associations with worry, depression, and social anxiety. In the analyses, NPO clustered particularly strongly with worry. The present results provide support for conceptualizing NPO as a cognitive variable common to emotional disorders, but not as related equivalently to all disorders within this category

    Self-assembly, structure and electronic properties of a quasiperiodic lead monolayer

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    A quasiperiodic Pb monolayer has been formed on the five-fold surface of the Al-Pd-Mn quasicrystal. Growth of the monolayer proceeds via self-assembly of an interconnected network of pentagonal Pb stars, which are shown to be tau-inflated compared to similar structural elements of the quasiperiodic substrate. Measurements of the electronic structure of the system using scanning tunnelling spectroscopy and ultra-violet photoemission spectroscopy reveal that the Pb monolayer displays a pseudo-gap at the Fermi level which is directly related to its quasiperiodic structure.Comment: 4 pages, 4 figure

    Nucleation of Pb starfish clusters on the five-fold Al-Pd-Mn quasicrystal surface

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    The nucleation of Pb clusters on the five-fold Al-Pd-Mn quasicrystal surface has been investigated using scanning tunneling microscopy (STM) and ab initio calculations based on density-functional theory (DFT). In the submonolayer regime, Pb atoms are highly mobile and adsorb preferentially within equatorially truncated pseudo-Mackay clusters present at the surface. The decoration of these unique adsorption sites leads to the formation of five-fold islands dubbed “starfish” and eventually to a quasiperiodic Pb monolayer. From a comparison of measured and calculated STM images it is concluded that most starfish clusters on all terraces are composed of ten Pb adatoms. A model of the structure of the starfish cluster has been proposed. Our total-energy calculations confirm its stability. The experimentally measured height profile of the starfish cluster is also reproduced by the DFT calculations

    Energy loss after daily role stress and work incivility: caring for oneself with emotional wellness

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    The present study seeks to build on burnout research by examining daily fuctuations of role stress and work incivility, and their impact on employees’ energy loss. Optimism and recovery (i.e., psychological detachment and relaxation), two mechanisms that allow workers’ self-care and self-defence from these toxic conditions when faced by these job stressors, were included. In a daily study, 117 service sector workers completed surveys three times a day, over a period of one working week. Hierarchical linear modeling revealed work incivility as predictor of daily emotional exhaustion. Optimism and recovery play diferent roles in protecting workers from daily energy loss. Daily optimism increased employees’energy and decreased emotional exhaustion and negative afect at night. It also moderated the relationship between work incivility and positive afect at night. The results on psychological detachment supported the stressor-detachment model (Sonnentag, 2010), in which psychological detachment from work during nonworking time is not only a direct predictor of increased energy, but could similarly bufer the negative impact of role stress and work incivility. Relaxation basically showed main efects in predicting emotional exhaustion (inversely) and positive afect (directly). Our fndings suggest two main implications: (1) the necessity for implemention of workplace policies to prevent role stress and work incivility in reducing daily loss of energy. (2) Training workers in self-care programmes focusing on optimism and recovery can provide early steps toward organizational change and employee daily well-beingThis research was supported by a project from the Spanish Ministry of Economy and Competitiveness (PSI2015-68011-R). Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Natur

    Reduced Fertility in Patients' Families Is Consistent with the Sexual Selection Model of Schizophrenia and Schizotypy

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    BACKGROUND: Schizophrenia is a mental disorder marked by an evolutionarily puzzling combination of high heritability, reduced reproductive success, and a remarkably stable prevalence. Recently, it has been proposed that sexual selection may be crucially involved in the evolution of schizophrenia. In the sexual selection model (SSM) of schizophrenia and schizotypy, schizophrenia represents the negative extreme of a sexually selected indicator of genetic fitness and condition. Schizotypal personality traits are hypothesized to increase the sensitivity of the fitness indicator, thus conferring mating advantages on high-fitness individuals but increasing the risk of schizophrenia in low-fitness individuals; the advantages of successful schzotypy would be mediated by enhanced courtship-related traits such as verbal creativity. Thus, schizotypy-increasing alleles would be maintained by sexual selection, and could be selectively neutral or even beneficial, at least in some populations. However, most empirical studies find that the reduction in fertility experienced by schizophrenic patients is not compensated for by increased fertility in their unaffected relatives. This finding has been interpreted as indicating strong negative selection on schizotypy-increasing alleles, and providing evidence against sexual selection on schizotypy. METHODOLOGY: A simple mathematical model is presented, showing that reduced fertility in the families of schizophrenic patients can coexist with selective neutrality of schizotypy-increasing alleles, or even with positive selection on schizotypy in the general population. If the SSM is correct, studies of patients' families can be expected to underestimate the true fertility associated with schizotypy. SIGNIFICANCE: This paper formally demonstrates that reduced fertility in the families of schizophrenic patients does not constitute evidence against sexual selection on schizotypy-increasing alleles. Futhermore, it suggests that the fertility estimates derived from extant studies may be biased to an unknown extent. These results have important implications for the evolutionary genetics of psychosis

    Evaluating enhanced recovery after surgery: time to cover new ground and discover the missing patient voice

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    Multicomponent peri-operative interventions offer to accelerate patient recovery and improve cost-effectiveness. The recent National Institute of Health Research-commissioned evidence synthesis review by Nunns et al. considers the effectiveness and cost-effectiveness of all types of multicomponent interventions for older adults undergoing elective inpatient surgery. Enhanced recovery programmes (ERPs) were the most commonly evaluated intervention. An association between ERPs and decreased length of stay was observed, whilst complication rates and time to recovery were static or sometimes reduced. Important areas which lack research in the context of ERPs are patient-reported outcome measures, patients with complex needs and assessment of factors pertaining to successful ERP implementation. The next generation of ERP studies should seek to develop our understanding in these key areas

    Portable X-ray fluorescence (pXRF) calibration for analysis of nutrient concentrations and trace element contaminants in fertilisers

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    With the increasing popularity of local blending of fertilisers, the fertiliser industry faces issues regarding quality control and fertiliser adulteration. Another problem is the contamination of fertilisers with trace elements that have been shown to subsequently accumulate in the soil and be taken up by plants, posing a danger to the environment and human health. Conventional characterisation methods necessary to ensure the quality of fertilisers and to comply with local regulations are costly, time consuming and sometimes not even accessible. Alternatively, using a wide range of unamended and intentionally amended fertilisers this study developed empirical calibrations for a portable handheld X-ray fluorescence (pXRF) spectrometer, determined the reliability for estimating the macro and micro nutrients and evaluated the use of the pXRF for the high-throughput detection of trace element contaminants in fertilisers. The models developed using pXRF for Mg, P, S, K, Ca, Mn, Fe, Zn and Mo had R2 values greater or equal to 0.97. These models also performed well on validation, with R2 values greater or equal to 0.97 (except for Fe, R2val = 0.55) and slope values ranging from 0.81 to 1.44. A second set of models were developed with a focus on trace elements in amended fertilisers. The R2 values of calibration for Co, Ni, As, Se, Cd and Pb were greater than or equal to 0.80. At concentrations up to 1000 mg kg-1, good validation statistics were also obtained; R2 values ranged from 0.97–0.99, except in one instance. The regression coefficients of the validation also had good prediction in the range of 0–100 mg kg-1 (R2 values were from 0.78–0.99), but not as well at lower concentrations up to 20 mg kg-1 (R2 values ranged from 0.10–0.99), especially for Cd. This study has demonstrated that pXRF can measure several major (P, Ca) and micro (Mn, Fe, Cu) nutrients, as well as trace elements and potential contaminants (Cr, Ni, As) in fertilisers with high accuracy and precision. The results obtained in this study is good, especially considering that loose powders were scanned for a maximum of 90 seconds without the use of a vacuum pump

    Self-Assembled Triply Periodic Minimal Surfaces as moulds for Photonic Band Gap Materials

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    We propose systems with structures defined by self-assembled triply periodic minimal surfaces (STPMS) as candidates for photonic bandgap materials. To support our proposal we have calculated the photonic bands for different STPMS and we have found that, at least, the double diamond and gyroid structures present full photonic bandgaps. Given the great variety of systems which crystalize in these structures, the diversity of possible materials that form them and the range of lattice constants they present, the construction of photonic bandgap materials with gaps in the visible range may be presently within reach.Comment: 3 pages, 2 figures, RevTe

    Antiproton Production in p+Ap+A Collisions at AGS Energies

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    Inclusive and semi-inclusive measurements are presented for antiproton (pˉ\bar{p}) production in proton-nucleus collisions at the AGS. The inclusive yields per event increase strongly with increasing beam energy and decrease slightly with increasing target mass. The pˉ\bar{p} yield in 17.5 GeV/c p+Au collisions decreases with grey track multiplicity, NgN_g, for Ng>0N_g>0, consistent with annihilation within the target nucleus. The relationship between NgN_g and the number of scatterings of the proton in the nucleus is used to estimate the pˉ\bar{p} annihilation cross section in the nuclear medium. The resulting cross section is at least a factor of five smaller than the free pˉ−p\bar{p}-p annihilation cross section when assuming a small or negligible formation time. Only with a long formation time can the data be described with the free pˉ−p\bar{p}-p annihilation cross section.Comment: 8 pages, 6 figure
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