871 research outputs found

    Macroscopic and Microscopic Entropy of Near-Extremal Spinning Black Holes

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    A seven parameter family of five-dimensional black hole solutions depending on mass, two angular momenta, three charges and the asymptotic value of a scalar field is constructed. The entropy is computed as a function of these parameters both from the Bekenstein-Hawking formula and from the degeneracies of the corresponding D-brane states in string theory. The expressions agree at and to leading order away from extremality.Comment: 7 pages, harvma

    Graviton Propagators on Fuzzy G/H

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    We describe closed string modes by open Wilson lines in noncommutative (NC) gauge theories on compact fuzzy G/H in IIB matrix model. In this construction the world sheet cut-off is related to the spacetime cut-off since the string bit of the symmetric traced Wilson line carries the minimum momentum on G/H. We show that the two point correlation functions of graviton type Wilson lines in 4 dimensional NC gauge theories behave as 1/(momentum)^2. This result suggests that graviton is localized on D3-brane, so we can naturally interpret D3-branes as our universe. Our result is not limited to D3-brane system, and we generalize our analysis to other dimensions and even to any topology of D-brane worldvolume within fuzzy G/H.Comment: 22 pages, 1 figure. minor correction

    Effective Potential on Fuzzy Sphere

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    The effective potential of quantized scalar field on fuzzy sphere is evaluated to the two-loop level. We see that one-loop potential behaves like that in the commutative sphere and the Coleman-Weinberg mechanism of the radiatively symmetry breaking could be also shown in the fuzzy sphere system. In the two-loop level, we use the heavy-mass approximation and the high-temperature approximation to perform the evaluations. The results show that both of the planar and nonplanar Feynman diagrams have inclinations to restore the symmetry breaking in the tree level. However, the contributions from planar diagrams will dominate over those from nonplanar diagrams by a factor N^2. Thus, at heavy-mass limit or high-temperature system the quantum field on the fuzzy sphere will behave like those on the commutative sphere. We also see that there is a drastic reduction of the degrees of freedom in the nonplanar diagrams when the particle wavelength is smaller than the noncommutativity scale.Comment: Latex 18 pages, some typos correcte

    Serum and bal beta-d-glucan for the diagnosis of Pneumocystis pneumonia in HIV positive patients

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    Background/purposeThe diagnosis of patients with pulmonary infiltrates and human immunodeficiency virus (HIV) infection remains a challenge. In current clinical practice the gold standard for Pneumocystis jirovecii pneumonia (PCP) diagnosis remains the identification of the organism in bronco alveolar lavage (BAL) using microscopy (e.g., silver stain). (1->3)-ÎČ -d-glucan (BG) is a polysaccharide that is present within the cell wall of Pneumocystis and other fungi.MethodsWe analyzed serum and BAL lavage fluid from a cohort of 119 patients that did have HIV, a diagnosis of pneumonia and underwent bronchoscopy (FOB) for diagnosis of PCP.ResultsThe discriminative power of serum BG for the diagnosis of PCP in this group of patients was very high. Using a cutoff of 300 pg/mL, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 91%, 92%, 89% and 93% respectively. A model for ROC with just serum BG (N = 108) had an AUC of 0.95. Serum procalcitonin (PCT) and BAL BG were not as accurate for the diagnosis of PCP. For BAL BG using a cutoff of 783 pg/mL, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 72%, 79%, 72% and 79% respectively. The differences between the medians for serum PCT between the group with a without PCP did not reach statistical significance (p = 0.6137).ConclusionThe measurement of serum BG should be incorporated in the diagnostic work up of HIV positive patients with dyspnea and infiltrates on chest X X-ray. Our study confirms the diagnostic value of serum BG previously reported by others but we add a cutoff value that we believe is more accurate for patients with AIDS and suspicion of PCP

    The Impact of an Adapted Climbing Program on Children with Attention-Deficit/Hyperactivity Disorder

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    Attention-Deficit/Hyperactivity Disorder impacts children’s participation in activities that require attention to instruction, sustained mental effort, and executive functioning. Physical activity has been correlated to improvement in attention in children with ADHD. Rock climbing challenges muscular endurance, attention, and route planning. Five participants, aged 8-13, participated in the climbing program. Attention was measured pre and post climbing intervention with Trail Making Test B (TMT-B) for time to complete. Exercise intensity was measured by heart rate. Parent feedback on behavior was collected with the Conner’s Parent Rating Scale (CPRS). The social validity of the intervention was measured by the IRP-15 measures. Statistically, significant intrasession attention improvements were noted in all 5 climbers (p=.43). Two climbers were consistently working at a moderate intensity (40-60% HRmax) while 3 climbers maintained a light level of intensity (20-40% HRmax). No statistically significant improvements were found on the CPRS, although improvements are noted with qualitative reports from parents. The IRP-15 showed 100% of parents believed rock climbing was an effective intervention for their children with ADHD. Rock climbing at a light to moderate intensity is associated with improvements in attention and behavior in children with ADHD

    Kinect vs. low-cost inertial sensing for gesture recognition

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    In this paper, we investigate efficient recognition of human gestures / movements from multimedia and multimodal data, including the Microsoft Kinect and translational and rotational acceleration and velocity from wearable inertial sensors. We firstly present a system that automatically classifies a large range of activities (17 different gestures) using a random forest decision tree. Our system can achieve near real time recognition by appropriately selecting the sensors that led to the greatest contributing factor for a particular task. Features extracted from multimodal sensor data were used to train and evaluate a customized classifier. This novel technique is capable of successfully classifying various gestures with up to 91 % overall accuracy on a publicly available data set. Secondly we investigate a wide range of different motion capture modalities and compare their results in terms of gesture recognition accuracy using our proposed approach. We conclude that gesture recognition can be effectively performed by considering an approach that overcomes many of the limitations associated with the Kinect and potentially paves the way for low-cost gesture recognition in unconstrained environments
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