194 research outputs found

    Evolution of chiral-odd spin-independent fracture functions in Quantum Cromodynamics

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    We construct the evolution equations for the twist-3 chiral-odd spin independent fracture functions in QCD. The Gribov-Lipatov reciprocity relation is fulfilled at the one-loop level for the quasi-partonic two-particle cut vertices only. It is found that the rang of the anomalous dimensions matrix is infinite for any given moment of the three-parton fracture function as distinguished from the case of DIS-distributions where the rang of the matrix was finite and increases with the number of the moment. In the multicolour limit Nc→∞N_c \to \infty the evolution equation for the quark-gluon-quark correlation function decouples from another equation in the system and becomes homogeneous provided we discard the quark mass effects. This fact provides an opportunity to find its analytic solution explicitly in nonlocal form similarly to the DIS.Comment: 16 pages, latex, no figure

    Anticoagulant rodenticides in red kites (Milvus milvus) in Britain in 2017 and 2018

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    Second generation anticoagulant rodenticides (SGARs) can be toxic to all mammals and birds. Various studies have shown that, in Britain, there is widespread exposure to SGARs in a diverse range of predatory mammals and birds, including red kites (Milvus milvus) which scavenge dead rats, a target species for rodent control. The Wildlife Incident Monitoring Scheme (WIIS) and the Predatory Bird Monitoring Scheme (PBMS) have shown that some mortalities result from this secondary exposure. In the present study, we analysed liver SGAR residues in 77 red kites that had been found dead in Britain in either 2017 or 2018. The carcasses were submitted to and necropsied by the Disease Risk Analysis and Health Surveillance (DRAHS) programme, the PBMS, the WIIS for England & Wales, the WIIS for Scotland and the Raptor Health Scotland study; the livers from the kites were subsequently analysed for SGAR residues. All the organisations are partners in the WILDCOMS network that promotes collaboration among surveillance schemes that monitor disease and contaminants in vertebrate wildlife. All of the 66 kites from England & Wales and 10 of the 11 red kites from Scotland had detectable liver residues of at least one SGAR. When considering the sample of kites as a whole, brodifacoum, difenacoum and bromadiolone were each detected in 73, 71 and 60 kites, respectively. Difethialone was found in 11 individuals while flocoumafen was detected in only one bird. Sum liver SGAR concentrations ranged between non-detected and 1218 ng/g wet wt. (arithmetic mean: 246 ng/g, median 154 ng/g). Post-mortem examinations indicated that 13 (16.8%) of red kites examined had internal haemorrhaging that was not associated with detectable trauma and had detectable liver SGAR concentrations. These birds had sum SGAR liver concentrations that ranged from 135 ng/g wet weight to 1218 ng/g wet weight. SGARs were considered a contributory cause of death in these cases. The stewardship scheme for anticoagulant rodenticides came fully into force in mid-2016 as re-registration of products for use in the UK was completed. A key aim is to reduce exposure of non-target wildlife to anticoagulant rodenticides but stewardship also aims to maintain efficacious rat control and so the number and density of AR-contaminated rats may remain unchanged. However, diligent searching, removal and safe disposal of poisoned rats, as promoted by stewardship, might be expected to reduce the availability of poisoned dead rats to red kites [and other scavengers] and thereby reduce the proportion of birds that are exposed and/or the magnitude of exposure. Concomitant with stewardship was a relaxation of the indoor use only restriction previously applied to brodifacoum, flocoumafen and difethialone, the three most acutely toxic SGARs. Any consequent increase in outdoor use of these three SGARs could increase the risk of secondary exposure in red kites. We therefore compared the data in the current report with that collected in 2015 and 2016 to determine if there was any evidence of a change in pattern or magnitude of exposure in red kites that might be connected to stewardship and/or change in usage restriction. The proportion of red kites exposed to SGARs in 2015 (90.6%), 2016 (89.6%) 2017 (96,4%) and 2018 (100%) was always 90% or more; the higher percentages in 2017 and 2018 were principally due to a greater proportion of birds from Scotland containing residues. Brodifacoum and difenacoum were the most prevalent compounds (89% of red kites across the four years for each compound) along with bromadiolone (75%). On average, there were residues of three different SGARs in each kite liver. There was no significant difference between years in liver sum (ÎŁ) SGAR concentrations. We investigated if there was a change between years in the exposure of red kites to brodifacoum, flocoumafen and difethialone, the compounds for which indoor only usage restrictions were relaxed in 2016. To enable statistical analysis of data on residue prevalence, it was necessary to pool the data into two-year blocks. Data on presence/absence of detectable brodifacoum, flocoumafen or difethialone residues were therefore compared for 2015/16 (pre and year of implementation of change in usage restriction) and 2017/18 (post-change in usage restriction). The proportion of red kites with detectable residues was 82% (50 out of 61 red kites) in 2015/16 but significantly higher (95%; 73 out of 77 red kites) in 2017/18. However, there was also an increase [albeit not statistically significant] in the proportion of red kites with detectable liver difenacoum or bromadiolone residues (90% in 2015/16 vs. 97% in 2017/18). Therefore, these data may simply reflect an increase in the prevalence of exposure to SGARs generally rather than any effect of change in usage restriction. There was no difference between the four years in the summed magnitude of liver brodifacoum, difethialone and flocoumafen concentrations. The percentage of red kites examined that were diagnosed as birds in which SGARs were implicated as a contributory cause of death did not differ significantly between individual years nor show a significant trend across the years; the overall average across the four years was 22%. However, if data were pooled by pairs of years (2017/8 vs 2015/16), the proportion of red kites for which SGARs were implicated as a contributory cause of death was lower (18%) in 2017/18 than in 2015/16 (33%) for red kites from England & Wales. Our findings do not indicate that there has been any reduction in exposure in red kites to SGARs following implementation of stewardship, in terms of either the proportion of individuals exposed or the magnitude of residues detected. There is some evidence (depending upon the statistical approach used) that the proportion of red kites in which SGARs were implicated as a contributory mortality factor has decreased in more recent years. There was no clear evidence that relaxation of usage restrictions on brodifacoum, difethialone and flocoumafen has altered the pattern of residue accumulation in red kites to date

    Colored Spin Systems, BKP Evolution and finite N_c effects

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    Even within the framework of the leading logarithmic approximation the eigenvalues of the BKP kernel for states of more than three reggeized gluons are unknown in general, contrary to the planar limit case where the problem becomes integrable. We consider a 4-gluon kernel for a finite number of colors and define some simple toy models for the configuration space dynamics, which are directly solvable with group theoretical methods. Then we study the dependence of the spectrum of these models with respect to the number of colors and make comparisons with the large limit case.Comment: 17 pages, 4 figures, references update, to appear on EPJ

    Kaon-Nucleon Scattering Amplitudes and Z∗^*-Enhancements from Quark Born Diagrams

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    We derive closed form kaon-nucleon scattering amplitudes using the ``quark Born diagram" formalism, which describes the scattering as a single interaction (here the OGE spin-spin term) followed by quark line rearrangement. The low energy I=0 and I=1 S-wave KN phase shifts are in reasonably good agreement with experiment given conventional quark model parameters. For klab>0.7k_{lab}> 0.7 Gev however the I=1 elastic phase shift is larger than predicted by Gaussian wavefunctions, and we suggest possible reasons for this discrepancy. Equivalent low energy KN potentials for S-wave scattering are also derived. Finally we consider OGE forces in the related channels KΔ\Delta, K∗^*N and K∗Δ^*\Delta, and determine which have attractive interactions and might therefore exhibit strong threshold enhancements or ``Z∗^*-molecule" meson-baryon bound states. We find that the minimum-spin, minimum-isospin channels and two additional K∗Δ^*\Delta channels are most conducive to the formation of bound states. Related interesting topics for future experimental and theoretical studies of KN interactions are also discussed.Comment: 34 pages, figures available from the authors, revte

    Definition and Calculation of Bottom Quark Cross-Sections in Deep-inelastic Scattering at HERA and Determination of their Uncertainties

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    The uncertainties involved in the calculation of bottom quark cross-sections in deep-inelastic scattering at HERA are studied in different phase space regions. Besides the inclusive bottom quark cross-section, definitions closer to the detector acceptance requiring at least one high energetic muon from the semi-leptonic \bquark decay or a jet with high transverse energy are investigated. For each case the uncertainties due to the choice of the renormalisation and factorisation scale as well as the \bquark mass are estimated in the perturbative NLO QCD calculation and furthermore uncertainties in the fragmenation of the bottom quark to a B-meson and in its semi-leptonic decay are discussed

    Gastric Marginal Zone B Cell Lymphoma of the Duodenum

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    Small bowel lymphomas of the extranodal type occur in the young and are characteristically associated with malabsorption syndrome. We present the case of an elderly in whom there was no malabsorption and the duodenal tumor was a gastric type marginal zone B cell lymphoma also known as gastric mucosa-associated lymphoid tissue (MALT) lymphoma. A 73-year-old woman presented to the emergency room with 2 weeks of general weakness, recurrent vomiting containing food particles and abdominal distension. She had been diagnosed with diabetic gastroparesis 4 years prior. CT of the abdomen and pelvis was suggestive of gastric outlet obstruction but no evidence of pancreatic or duodenal mass. Endoscopy and biopsy of the tumor obstructing the distal first part of the duodenum confirmed a gastric marginal MALT lymphoma. The patient's symptoms improved with radiotherapy. Gastric MALT lymphoma, an extranodal lymphoma primarily described in the stomach, can also present in the small bowel and is not associated with malabsorption

    Anticoagulant rodenticides in red kites (Milvus milvus) in Britain 2015

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    Second generation anticoagulant rodenticides (SGARs) can be toxic to all mammals and birds. Various studies have shown that, in Britain, there is widespread exposure to SGARs in a diverse range of predatory mammals and birds, including red kites (Milvus milvus) which scavenge dead rats, a target species for rodent control. The Wildlife Incident Monitoring Scheme (WIIS) and the Predatory Bird Monitoring Scheme (PBMS) have shown that some mortalities result from this secondary exposure. The aim of the current study was to assess the scale and severity of exposure to SGARs (as assessed from the presence of liver SGAR residues) in red kites found dead in Britain in 2015. Carcasses, typically found by members of the public, were submitted for examination and analysis either to the Institute of Zoology’s Disease Risk Analysis and Health Surveillance programme (DRAHS) or to the Centre for Ecology & Hydrology’s Predatory Bird Monitoring Scheme, partners in the WILDCOMS network. We also report the results of SGAR analysis of red kites from England, Wales and Scotland that died in 2015 and analysed by the WIIS, who are also partners of the WILDCOMS network. Eighteen red kites from England & Wales were necropsied by either the DRAHS or the PBMS and the livers of the birds were analysed for SGARs by the PBMS. All had detectable liver residues of difenacoum and brodifacoum, and most also contained detectable liver bromadiolone residues. Difethialone was less frequently detected and flocoumafen was not detected in any birds. The presence of detectable brodifacoum residues in all birds may partly reflect the predominance of adult birds in the 2015 sample but may also indicate a growing prevalence of exposure to this compound. The percentage of red kites found by the PBMS to contain brodifacoum has increased since 2010 although any influence of age on this trend has not yet been examined. Sum liver SGAR concentrations in the 18 kites ranged between 50 and 1266 ng/g wet wt. (arithmetic mean: 463 ng/g). Post-mortems indicated that 7 of the kites had internal hemorrhaging that was not associated with detectable trauma; these birds typically had elevated sum SGAR liver concentrations. On the basis of these two factors, it is considered probable that SGARs were a contributory cause of death in these birds. The exposure pattern observed in 8 red kites from England & Wales analysed by the WIIS was very similar to that observed in birds analysed by the PBMS, with detectable liver residues of difenacoum and brodifacoum in all birds and bromadiolone in most. SGARs were assessed to be a contributory cause of death in two birds. Thus, of the 26 red kites from England & Wales analysed overall, SGARs were considered to be implicated in the deaths of 9 (35%). Residue data were available through the WIIS for 6 red kites from Scotland that died in 2015. Three kites (50%) had liver residues of at least two SGARs (bromadiolone and difenacoum); brodifacoum was also detected in one of these kites. SGARs were assessed to be a contributory cause of death in the bird that had residues of three SGARs. The data, although sample size is small, suggest that exposure of kites to SGARs may have been less marked in Scotland than in England & Wales in 2015, as has been found for other species

    Z^* Resonances: Phenomenology and Models

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    We explore the phenomenology of, and models for, the Z^* resonances, the lowest of which is now well established, and called the Theta. We provide an overview of three models which have been proposed to explain its existence and/or its small width, and point out other relevant predictions, and potential problems, for each. The relation to what is known about KN scattering, including possible resonance signals in other channels, is also discussed.Comment: 29 pages, uses RevTeX4; expanded version (published form

    The pattern of growth hormone secretion during the menstrual cycle in normal and depressed women

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    Objective Major depression is associated to altered hypothalamic pituitary function. Stress is linked to elevated cortisol as well as menstrual cycle disturbance; however, there is no known relationship between depression and menstrual cycle disruption. The aim of this study was to investigate changes of growth hormone (GH) secretion during the menstrual cycle in normal and depressed women. Design Case-control study. Patients and methods Nineteen women affected with depression and 24 normal controls were included. The two groups had comparable body mass index (BMI), and age (29·4 ±9·8 vs. 28·6 ± 9·7 years). Nine depressed and 10 controls were studied in the follicular phase, while 10 depressed and 14 controls were studied in the luteal phase of the cycle. GH was sampled every 10 min for 24 h, and the data were analysed by the cluster pulse detection method. Results There was no difference in 24-h mean GH concentrations between depressed and control subjects (P =0·93), even after accounting for menstrual cycle phase (P = 0·38). GH pulse frequency was higher during the follicular phase of the cycle (P =0·032), and nocturnal GH was higher in the follicular phase of the cycle (P =0·05, and after adjusting for 24-h GH, P= 0·0138) regardless of whether thesubjects were depressed or healthy. Conclusions In studies of GH secretion in women with or without depression, it is necessary to control for the phase of menstrual cycle.NIMH MH 50030 NICHD K12HD01438Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49486/2/KasaVubuYoung.pd

    Primeval Corrections to the CMB Anisotropies

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    We show that deviations of the quantum state of the inflaton from the thermal vacuum of inflation may leave an imprint in the CMB anisotropies. The quantum dynamics of the inflaton in such a state produces corrections to the inflationary fluctuations, which may be observable. Because these effects originate from IR physics below the Planck scale, they will dominate over any trans-Planckian imprints in any theory which obeys decoupling. Inflation sweeps away these initial deviations and forces its quantum state closer to the thermal vacuum. We view this as the quantum version of the cosmic no-hair theorem. Such imprints in the CMB may be a useful, independent test of the duration of inflation, or of significant features in the inflaton potential about 60 e-folds before inflation ended, instead of an unlikely discovery of the signatures of quantum gravity. The absence of any such substructure would suggest that inflation lasted uninterrupted much longer than O(100){\cal O}(100) e-folds.Comment: 17 pages, latex, no figures; v3: added references and comments, final version to appear in Phys. Rev.
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