2,524 research outputs found
Transverse Spin Structure of the Nucleon through Target Single Spin Asymmetry in Semi-Inclusive Deep-Inelastic Reaction at Jefferson Lab
Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to
perform precision studies of the transverse spin and
transverse-momentum-dependent structure in the valence quark region for both
the proton and the neutron. In this paper, we focus our discussion on a
recently approved experiment on the neutron as an example of the precision
studies planned at JLab. The new experiment will perform precision measurements
of target Single Spin Asymmetries (SSA) from semi-inclusive electro-production
of charged pions from a 40-cm long transversely polarized He target in
Deep-Inelastic-Scattering kinematics using 11 and 8.8 GeV electron beams. This
new coincidence experiment in Hall A will employ a newly proposed solenoid
spectrometer (SoLID). The large acceptance spectrometer and the high polarized
luminosity will provide precise 4-D (, , and ) data on the
Collins, Sivers, and pretzelocity asymmetries for the neutron through the
azimuthal angular dependence. The full 2 azimuthal angular coverage in the
lab is essential in controlling the systematic uncertainties. The results from
this experiment, when combined with the proton Collins asymmetry measurement
and the Collins fragmentation function determined from the ee collision
data, will allow for a quark flavor separation in order to achieve a
determination of the tensor charge of the d quark to a 10% accuracy. The
extracted Sivers and pretzelocity asymmetries will provide important
information to understand the correlations between the quark orbital angular
momentum and the nucleon spin and between the quark spin and nucleon spin.Comment: 23 pages, 13 figures, minor corrections, matches published versio
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An ASKAP Search for a Radio Counterpart to the First High-significance Neutron Star-Black Hole Merger LIGO/Virgo S190814bv
We present results from a search for a radio transient associated with the LIGO/Virgo source S190814bv, a likely neutron star-black hole (NSBH) merger, with the Australian Square Kilometre Array Pathfinder. We imaged a 30 deg2 field at ΞT = 2, 9, and 33 days post-merger at a frequency of 944 MHz, comparing them to reference images from the Rapid ASKAP Continuum Survey observed 110 days prior to the event. Each epoch of our observations covers 89% of the LIGO/Virgo localization region. We conducted an untargeted search for radio transients in this field, resulting in 21 candidates. For one of these, AT2019osy, we performed multiwavelength follow-up and ultimately ruled out the association with S190814bv. All other candidates are likely unrelated variables, but we cannot conclusively rule them out. We discuss our results in the context of model predictions for radio emission from NSBH mergers and place constrains on the circum-merger density and inclination angle of the merger. This survey is simultaneously the first large-scale radio follow-up of an NSBH merger, and the most sensitive widefield radio transients search to-date
Bosonic excitations of the AdS4 Reissner-Nordstrom black hole
We study the long-lived modes of the charge density and energy density
correlators in the strongly-coupled, finite density field theory dual to the
AdS4 Reissner-Nordstrom black hole. For small momenta q<<\mu, these correlators
contain a pole due to sound propagation, as well as a pole due to a long-lived,
purely imaginary mode analogous to the \mu=0 hydrodynamic charge diffusion
mode. As the temperature is raised in the range T\lesssim\mu, the sound
attenuation shows no significant temperature dependence. When T\gtrsim\mu, it
quickly approaches the \mu=0 hydrodynamic result where it decreases like 1/T.
It does not share any of the temperature-dependent properties of the 'zero
sound' of Landau Fermi liquids observed in the strongly-coupled D3/D7 field
theory. For such small momenta, the energy density spectral function is
dominated by the sound mode at all temperatures, whereas the charge density
spectral function undergoes a crossover from being dominated by the sound mode
at low temperatures to being dominated by the diffusion mode when T \mu^2/q.
This crossover occurs due to the changing residue at each pole. We also compute
the momentum dependence of these spectral functions and their corresponding
long-lived poles at fixed, low temperatures T<<\mu.Comment: 33 pages, 21 figures, 6 animation
Clinical and genetic characterisation of dystrophin-deficient muscular dystrophy in a family of Miniature Poodle dogs
Four full-sibling intact male Miniature Poodles were evaluated at 4β19 months of age. One was clinically normal and three were affected. All affected dogs were reluctant to exercise and had generalised muscle atrophy, a stiff gait and a markedly elevated serum creatine kinase activity. Two affected dogs also showed poor development, learning difficulties and episodes of abnormal behaviour. In these two dogs, investigations into forebrain structural and metabolic diseases were unremarkable; electromyography demonstrated fibrillation potentials and complex repetitive discharges in the infraspinatus, supraspinatus and epaxial muscles. Histopathological, immunohistochemical and immunoblotting analyses of muscle biopsies were consistent with dystrophin-deficient muscular dystrophy. DNA samples were obtained from all four full-sibling male Poodles, a healthy female littermate and the dam, which was clinically normal. Whole genome sequencing of one affected dog revealed a >5 Mb deletion on the X chromosome, encompassing the entire DMD gene. The exact deletion breakpoints could not be experimentally ascertained, but we confirmed that this region was deleted in all affected males, but not in the unaffected dogs. Quantitative polymerase chain reaction confirmed all three affected males were hemizygous for the mutant X chromosome, while the wildtype chromosome was observed in the unaffected male littermate. The female littermate and the dam were both heterozygous for the mutant chromosome. Forty-four Miniature Poodles from the general population were screened for the mutation and were homozygous for the wildtype chromosome. The finding represents a naturally-occurring mutation causing dystrophin-deficient muscular dystrophy in the dog
Outcome measurement in functional neurological disorder: a systematic review and recommendations.
OBJECTIVES: We aimed to identify existing outcome measures for functional neurological disorder (FND), to inform the development of recommendations and to guide future research on FND outcomes. METHODS: A systematic review was conducted to identify existing FND-specific outcome measures and the most common measurement domains and measures in previous treatment studies. Searches of Embase, MEDLINE and PsycINFO were conducted between January 1965 and June 2019. The findings were discussed during two international meetings of the FND-Core Outcome Measures group. RESULTS: Five FND-specific measures were identified-three clinician-rated and two patient-rated-but their measurement properties have not been rigorously evaluated. No single measure was identified for use across the range of FND symptoms in adults. Across randomised controlled trials (k=40) and observational treatment studies (k=40), outcome measures most often assessed core FND symptom change. Other domains measured commonly were additional physical and psychological symptoms, life impact (ie, quality of life, disability and general functioning) and health economics/cost-utility (eg, healthcare resource use and quality-adjusted life years). CONCLUSIONS: There are few well-validated FND-specific outcome measures. Thus, at present, we recommend that existing outcome measures, known to be reliable, valid and responsive in FND or closely related populations, are used to capture key outcome domains. Increased consistency in outcome measurement will facilitate comparison of treatment effects across FND symptom types and treatment modalities. Future work needs to more rigorously validate outcome measures used in this population
Emotional stress as a trigger of myasthenic crisis and concomitant takotsubo cardiomyopathy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Myasthenia gravis is a neuromuscular junction post-synaptic autoimmune disorder. Myasthenic crisis is characterized by respiratory failure requiring mechanical ventilation. Takotsubo cardiomyopathy is a rare clinical syndrome defined as a profound but reversible left ventricular dysfunction in the absence of coronary artery disease.</p> <p>Case presentation</p> <p>We report a unique case of a 60-year-old Hispanic woman with myasthenia gravis who developed takotsubo cardiomyopathy and concomitant myasthenic crisis that appear to have been triggered by a stressful life event. On admission, she presented with severe mid-sternal chest pain and shortness of breath shortly after a personally significant stressful life event. A pertinent neurological examination showed bilateral facial weakness and right ptosis. The left ventriculogram showed apical ballooning with hyperdynamic proximal segments with sparing of the apex. Her troponin I level was elevated, while cardiac catheterization revealed no significant coronary artery disease. The findings were consistent with takotsubo cardiomyopathy. Shortly after cardiac catheterization, she developed bilateral ophthalmoparesis and significant bulbar and respiratory muscle weakness. Forced vital capacity values were persistently less than 1 L. The patient developed respiratory failure and required endotracheal intubation. After plasmapheresis and corticosteroid treatment, her clinical course improved with successful extubation. A normal left ventricle chamber size and a normal ejection fraction were noted by an echocardiogram repeated 10 months later.</p> <p>Conclusion</p> <p>This is the first reported case of the simultaneous triggering of both takotsubo cardiomyopathy and myasthenic crisis by the physiologic consequences of a state of severe emotional stress. We hypothesize that the mechanism underlying the rare association of takotsubo cardiomyopathy with myasthenic crisis involves excessive endogenous glucocorticoid release, a high-catecholamine state, or a combination of both. We advocate careful cardiac monitoring of myasthenia gravis patients during acute emotional or physical stress, as there is potential risk of developing takotsubo cardiomyopathy.</p
Modulation of emotional appraisal by false physiological feedback during fMRI
BACKGROUND
James and Lange proposed that emotions are the perception of physiological reactions. Two-level theories of emotion extend this model to suggest that cognitive interpretations of physiological changes shape self-reported emotions. Correspondingly false physiological feedback of evoked or tonic bodily responses can alter emotional attributions. Moreover, anxiety states are proposed to arise from detection of mismatch between actual and anticipated states of physiological arousal. However, the neural underpinnings of these phenomena previously have not been examined.
METHODOLOGY/PRINCIPAL FINDINGS
We undertook a functional brain imaging (fMRI) experiment to investigate how both primary and second-order levels of physiological (viscerosensory) representation impact on the processing of external emotional cues. 12 participants were scanned while judging face stimuli during both exercise and non-exercise conditions in the context of true and false auditory feedback of tonic heart rate. We observed that the perceived emotional intensity/salience of neutral faces was enhanced by false feedback of increased heart rate. Regional changes in neural activity corresponding to this behavioural interaction were observed within included right anterior insula, bilateral mid insula, and amygdala. In addition, right anterior insula activity was enhanced during by asynchronous relative to synchronous cardiac feedback even with no change in perceived or actual heart rate suggesting this region serves as a comparator to detect physiological mismatches. Finally, BOLD activity within right anterior insula and amygdala predicted the corresponding changes in perceived intensity ratings at both a group and an individual level.
CONCLUSIONS/SIGNIFICANCE
Our findings identify the neural substrates supporting behavioural effects of false physiological feedback, and highlight mechanisms that underlie subjective anxiety states, including the importance of the right anterior insula in guiding second-order "cognitive" representations of bodily arousal state
Modulation of emotional appraisal by false physiological feedback during fMRI
BACKGROUND
James and Lange proposed that emotions are the perception of physiological reactions. Two-level theories of emotion extend this model to suggest that cognitive interpretations of physiological changes shape self-reported emotions. Correspondingly false physiological feedback of evoked or tonic bodily responses can alter emotional attributions. Moreover, anxiety states are proposed to arise from detection of mismatch between actual and anticipated states of physiological arousal. However, the neural underpinnings of these phenomena previously have not been examined.
METHODOLOGY/PRINCIPAL FINDINGS
We undertook a functional brain imaging (fMRI) experiment to investigate how both primary and second-order levels of physiological (viscerosensory) representation impact on the processing of external emotional cues. 12 participants were scanned while judging face stimuli during both exercise and non-exercise conditions in the context of true and false auditory feedback of tonic heart rate. We observed that the perceived emotional intensity/salience of neutral faces was enhanced by false feedback of increased heart rate. Regional changes in neural activity corresponding to this behavioural interaction were observed within included right anterior insula, bilateral mid insula, and amygdala. In addition, right anterior insula activity was enhanced during by asynchronous relative to synchronous cardiac feedback even with no change in perceived or actual heart rate suggesting this region serves as a comparator to detect physiological mismatches. Finally, BOLD activity within right anterior insula and amygdala predicted the corresponding changes in perceived intensity ratings at both a group and an individual level.
CONCLUSIONS/SIGNIFICANCE
Our findings identify the neural substrates supporting behavioural effects of false physiological feedback, and highlight mechanisms that underlie subjective anxiety states, including the importance of the right anterior insula in guiding second-order "cognitive" representations of bodily arousal state
Knowledge and exposure to complementary and alternative medicine in paediatric doctors: a questionnaire survey
<p>Abstract</p> <p>Background</p> <p>Complementary and alternative medicines are increasingly used by the general population. A survey was conducted to ascertain the knowledge of Complementary and Alternative Medicines (CAMs) amongst paediatric physicians, and whether seniority increases the likelihood of its use being considered in consultations, or of families discussing it.</p> <p>Methods</p> <p>Anonymous survey of general paediatric doctors in a large inner-city district general hospital (DGH) and tertiary children's centre (TC) using a questionnaire. Statistical analysis was calculated using Minitab.</p> <p>Results</p> <p>43/49 (88%) questionnaires were returned correctly. 13 (30%, CI 17 β 46%) doctors had personally used CAMs. 24 (56%, CI 40 β 71%) of their families had used CAMs. 13 (30%, CI 17 β 46%) had received formal CAMs education. 21 (49%, CI 40 β 71%) could name a total of 5 types of CAMs. Consultants were significantly more likely to ask about CAM use than middle-grades and juniors (p < 0.05, CI 48 β 93%, 35 β 90%, 8 β 33% respectively) and have had a clinical encounter where they felt it was significant. 32 (74%, CI 59 β 86%) of the clinicians had been asked about CAMs. 33 (77%, CI 61 β 88%) of doctors had successful CAM use reported to them, and 20 (47%, CI 31 β 62%) had failure of CAMs reported to them.</p> <p>Conclusion</p> <p>CAM use is relatively common in paediatric doctors and their families. They have received little formal CAMs education. Consultants were more likely than juniors to ask about CAM use and have had a clinical encounter where it played a significant part. Around half of all doctors irrespective of grade have been asked about CAMs in a clinical encounter.</p
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