5,441 research outputs found

    Scale-factor duality in string Bianchi cosmologies

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    We apply the scale factor duality transformations introduced in the context of the effective string theory to the anisotropic Bianchi-type models. We find dual models for all the Bianchi-types [except for types VIIIVIII and IXIX] and construct for each of them its explicit form starting from the exact original solution of the field equations. It is emphasized that the dual Bianchi class BB models require the loss of the initial homogeneity symmetry of the dilatonic scalar field.Comment: 18 pages, no figure

    Tactile Thresholds are Preserved yet Cortical Sensory Function is Impaired in Chronic Non-Specific Low Back Pain Patients

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    Introduction: A substantial amount of evidence points to an alteration in brain structure and function patients with chronic non-specific low back pain (CNSLBP) [1-6]. One interpretation of these findings is that the observed brain changes may represent a disruption of the brain’s representations of the body part and the resultant body perception disturbance may underpin this clinical problem. The current study aimed to investigate sensory dysfunction in CNSLBP. Specifically we aimed to distinguish cortically mediated sensory dysfunction from peripheral dysfunction by comparing simple tactile thresholds with more complex cortically mediated sensory tests Methods: We investigated tactile thresholds (TTH), two point discrimination (TPD) and graphaesthesia over the lumbar spine of 19 CLBP patients and 19 age and sex matched healthy controls as a way of investigating whether CLBP patients present with a perceptual disturbance of their lumbar spine. Differences in performance of the sensory tests was explored using the Mann Whitney U Test and one-way between groups multivariate analysis of variance. Results: We found no difference in tactile threshold between the two groups (P=.0.751). There was a statistically significant difference between controls and LBP for TPD: F(1,36)=10.15, p=.003 and letter error rate: F(1, 36)=6.54 p=0.015. The data indicate that LBP patients had a larger lumbar TPD distance and a greater letter recognition error rate. Discussion: Both TPD and graphaesthesia are dependant on the integrity of the primary sensory cortex [7]. These data support existing findings of perceptual abnormality in chronic back pain [8] and the preservation of tactile thresholds is suggestive of cortical rather than peripheral sensory dysfunction. Amelioration of these abnormalities may present a target for therapeutic intervention

    Vacuum stability, fixed points, and phases of QED3 at large Nf

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    We consider three-dimensional quantum electrodynamics in the presence of a Chern-Simons term at level k and Nf flavors, in the limit of large Nf and k with k/Nf fixed. We consider either bosonic or fermionic matter fields, with and without quartic terms at criticality: the resulting theories are critical and tricritical bosonic QED3, Gross-Neveu, and fermionic QED3. For all such theories we compute the effective potentials and the beta functions of classically marginal couplings, at the leading order in the large Nf limit and to all orders in k/Nf and in the couplings. We determine the renormalization group fixed points and discuss the quantum stability of the corresponding vacua. While critical bosonic and fermionic QED3 are always stable conformal field theories, we find that tricritical bosonic and Gross-Neveu QED3 exist as stable conformal field theories only for specific values of k/Nf. Finally, we discuss the phase diagrams of these theories as a function of their relevant deformations

    Multiple ectopic leiomyomas of the abdominal rectus muscles after gasless laparoscopic uterine myomectomy

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    To describe and analyze the first case of multiple ectopic leiomyomas of the abdominal rectus muscles in a patient who had undergone gasless laparoscopic uterine myomectomy (GLM) 10 years before

    The academic impact of natural disasters: evidence from L’Aquila earthquake

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    This paper uses a standard difference-in-differences approach to examine the effect of the L’Aquila earthquake on the academic performance of the students of the local university. The empirical results indicate that this natural disaster reduced students’ probability of graduating on-time and slightly increased students’ probability of dropping out. While post-disaster measures (e.g. fast re-establishment of education activities in temporary locations) are likely to have mitigated the effects of this event, disruptions in the learning environment and the mental trauma suffered by students in the aftermath of the earthquake may have worsened their academic performance

    Return visits to the Paediatric Emergency Department: first analysis in Italy

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    Return visits to the emergency room have come under scrutiny with a view to identifying the reasons for these events. The aim of the study was to estimate the incidence of return visits to emer- gency room and to compare this with data from other countries, with a view to proposing a method of monitoring this parameter nationwide. Ours is the first Italian study to report the incidence of return visits to the ER and to analyse the factors correlated with this phenomenon. The incidence of return visits within 72 hours of the first visit proved to be 2.5%. Statistical analysis revealed a significant difference in the number of return visits between patients under 1 year of age and those older than 1 year. Our future objective is to re-analyse recent case-records on the basis of the indicators identified, with a view to assessing the quality of the service

    Assessment of the Triage System in a Pediatric Emergency Department. A pilot study on critical code

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    Introduction. In Italy, triage involves assigning a priority color code to patients arriving at the hospital Emergency Department: red (very critical), yellow (moderately critical), green (not very critical), and white (not critical). Methods. This study was aimed at assessing the triage system in the Emergency Department of ?Giannina Gaslini? Children? s Hospital in Genoa, Italy. The authors examined 130 triage forms assigning a yellow code in 2003, in order to determine whether they had been correctly filled in with regard to the detection of vital parameters, identification of main symptoms and color code assignment. Results. Results showed that vital signs were recorded in 94% of patients, main symptoms were identified in 97%, and a yel- low code was assigned according to hospital guidelines in 84%. The percentage of underestimation (3.2%) was higher than that reported in the literature (2%). Conclusions. The study shows the need to improve compliance with the guidelines and to evaluate green and white codes
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