540 research outputs found

    A relativistic model for neutrino pion production from nuclei in the resonance region

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    We present a relativistic model for electroweak pion production from nuclei, focusing on the Δ\Delta and the second resonance region. Bound states are derived in the Hartree approximation to the σ−ω\sigma-\omega Walecka model. Final-state interactions of the outgoing pion and nucleon are described in a factorized way by means of a relativistic extension of the Glauber model. Our formalism allows a detailed study of neutrino pion production through Q2Q^2, WW, energy, angle and out-of-plane distributions.Comment: 3 pages, 1 figure, poster presented at the NuInt07 conference on few-GeV neutrino physic

    A Self-powered And Autonomous Fringing Field Capacitive Sensor Integrated Into A Micro Sprinkler Spinner To Measure Soil Water Content

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    We present here the design and fabrication of a self- powered and autonomous fringing field capacitive sensor to measure soil water content. The sensor is manufactured using a conventional printed circuit board and includes a porous ceramic. To read the sensor, we use a circuit that includes a 10 kHz triangle wave generator, an AC amplifier, a precision rectifier and a microcontroller. In terms of performance, the sensor's capacitance ( measured in a laboratory prototype) increases up to 5% when the volumetric water content of the porous ceramic changed from 3% to 36%, resulting in a sensitivity of S = 15.5 pF per unity change. Repeatability tests for capacitance measurement showed that the theta(v) sensor's root mean square error is 0.13%. The average current consumption of the system ( sensor and signal conditioning circuit) is less than 1.5 mu A, which demonstrates its suitability for being powered by energy harvesting systems. We developed a complete irrigation control system that integrates the sensor, an energy harvesting module composed of a microgenerator installed on the top of a micro sprinkler spinner, and a DC/ DC converter circuit that charges a 1 F supercapacitor. The energy harvesting module operates only when the micro sprinkler spinner is irrigating the soil, and the supercapacitor is fully charged to 5 V in about 3 h during the first irrigation. After the first irrigation, with the supercap fully charged, the system can operate powered only by the supercapacitor for approximately 23 days, without any energy being harvested.17

    Measurement Of The Electric Energy Storage Capacity In Solar Thermoelectric Generators' Energy Harvesting Modules

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    Reducing energy consumption is mandatory in self-powered sensor nodes of wireless sensor networks that obtain all their energy from the environment. In this direction, one first step to optimize the network is to accurately measure the total energy harvested, which will determine the power available for sensor consumption. We present here a technique based on an embedded circuit with an ultra-low-power microcontroller to accurately measure the efficiency of flat-panel solar thermoelectric generators operating with environmental temperature gradients. Experimental tests showed that when a voltage of 180 mV (best case in an environmental flat-panel solar thermoelectric generators) is applied to the input of the DC-DC converter, the proposed technique eliminates a measurement error of 33% when compared with the conventional single supercapacitor strategy.13

    Cerebral Regulation In Different Maximal Aerobic Exercise Modes

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We investigated cerebral responses, simultaneously with peripheral and ratings of perceived exertion (RPE) responses, during different VO2MAX-matched aerobic exercise modes. Nine cyclists (VO2MAX of 57.5 +/- 6.2 ml.kg(-1).min(-1)) performed a maximal, controlled-pace incremental test (MIT) and a self-paced 4 km time trial (TT4km). Measures of cerebral (COX) and muscular (MOX) oxygenation were assessed throughout the exercises by changes in oxy-(O(2)Hb) and deoxy-hemoglobin (HHb) concentrations over the prefrontal cortex (PFC) and vastus lateralis (VL) muscle, respectively. Primary motor cortex (PMC) electroencephalography (EEG), VL, and rectus femoris EMG were also assessed throughout the trials, together with power output and cardiopulmonary responses. The RPE was obtained at regular intervals. Similar motor output (EMG and power output) occurred from 70% of the duration in MIT and TT4km, despite the greater motor output, muscle deoxygenation (down arrow MOX) and cardiopulmonary responses in TT4km before that point. Regarding cerebral responses, there was a lower COX (1, O(2)Hb concentrations in PFC) at 20, 30, 40, 50 and 60%, but greater at 100% of the TT4km duration when compared to MIT The alpha wave EEG in PMC remained constant throughout the exercise modes, with greater values in TT4km. The RPE was maximal at the endpoint in both exercises, but it increased slower in TT4km than in MIT. Results showed that similar motor output and effort tolerance were attained at the closing stages of different VO2MAX-matched aerobic exercises, although the different disturbance until that point. Regardless of different COX responses during most of the exercises duration, activation in PMC was preserved throughout the exercises, suggesting that these responses may be part of a centrally coordinated exercise regulation.7FAPESP-Brazil [2010/01317-0]FAPESP [2005/56578-4, 2015/13096-1]CNPq-Brazil [480702/2010-1, 303085/2015-0]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Pair condensation in the BCS-BEC crossover of ultracold atoms loaded onto a 2D square lattice

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    We investigate the crossover from the Bardeen-Cooper-Schrieffer (BCS) state of weakly-bound Cooper pairs to the Bose-Einstein Condensate (BEC) of strongly-bound molecular dimers in a gas of ultracold atoms loaded on a two-dimensional optical lattice. By using the the mean-field BCS equations of the emerging Hubbard model and the concept of off-diagonal-long-range-order for fermions we calculate analytically and numerically the pair binding energy, the energy gap and the condensate fraction of Cooper pairs as a function of interaction strength and filling fractor of atoms in the lattice at zero temperature.Comment: 7 pages, 5 figures, to be published in Phys. Rev.

    Biodegradable nanoparticles containing benzopsoralens : an attractive strategy for modifying vascular function in pathological skin disorders

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    Psoralens are often used to treat skin disorders such as psoriasis, vitiligo and others. The toxicity and fast degradation of these drugs can be diminished by encapsulation in drug delivery systems (DDS). Nanoparticles (NPs) containing the benzopsoralen (BP) (3-ethoxy carbonyl-2H-benzofuro[3,2-e]-1-benzopiran-2-one) were prepared by the solvent evaporation technique, and parameters such as particle size, zeta potential, drug encapsulation efficiency, and external morphology were evaluated. The analysis revealed that the NPs are spherical and possessed a smooth external surface with diameter of 815 ± 80 nm, they present low tendency toward aggregation, as confirmed by their zeta potential (+17.3±2.9 mV) and the encapsulation efficiency obtained was 74%. The intracellular distribution of NPs as well as their uptake by tissues was monitored by using laser confocal microscopy and transmission electron microscopy. The use of benzopsoralen in association with ultraviolet light (360 nm) revealed morphological characteristics of cell damage such as cytosolic vesiculation, mitochondria condensation, and swelling of both the granular endoplasmic reticulum and the nuclear membrane. The primary target of DDS and drugs in vascular system are endothelial cells and an attractive strategy for modifying vascular function in various pathological states of skin disorders, cancer and inflammation. The result presented in this work indicates that PLGA NP could be a promising delivery system for benzopsoralen in connection with ultraviolet irradiation therapy (PUVA) for further application in different therapies.CNPq , CAPES, FAPESP (Braisl

    The metabolic pattern of idiopathic REM sleep behavior disorder reflects early-stage Parkinson's disease

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    Rationale: Idiopathic REM sleep behavior disorder (iRBD) is considered a prodromal stage of Parkinson's disease (PD) and other Lewy-body disorders. Spatial covariance analysis of [18F]-Fluorodeoxyglucose Positron Emission Tomography (18F-FDG-PET) data has disclosed a specific brain pattern of altered glucose metabolism in PD. In this study, we identify the metabolic pattern underlying iRBD and compare it to the known PD pattern. To understand the relevance of the iRBD pattern to disease progression, we study the expression of the iRBD pattern in de novo PD patients.Methods:The iRBD-related pattern was identified in18F-FDG-PET scans of 21 patients with polysomnographically-confirmed iRBD and 19 controls using spatial covariance analysis. Expression of the iRBD-related pattern was subsequently computed in18F-FDG-PET scans of 44 controls and 38 de novo, treatment-naïve PD patients. Of these 38 PD patients, 24 had probable RBD according to the Mayo Sleep Questionnaire. Neuropsychological evaluation showed mild cognitive impairment in 20 PD patients (PD-MCI), of whom sixteen also had concomitant RBD and roughly half (11/20) had bilateral motor symptoms.Results:The iRBD-related pattern was characterized by relative hypermetabolism in cerebellum, brainstem, thalamus, sensorimotor cortex, and hippocampus, and by relative hypometabolism in middle cingulate, temporal, occipital and parietal cortices. This topography partially overlapped with the PD-related pattern (PDRP). The iRBD-related pattern was significantly expressed in PD patients compared to controls (P<0.0001). iRBD-related pattern expression was not significantly different between PD patients with and without probable RBD, or between PD patients with unilateral or bilateral parkinsonism. iRBD-related pattern expression was higher in PD-MCI patients, compared to PD patients with preserved cognition (P= 0.001). Subject scores on the iRBD-related pattern were highly correlated to subject scores on the PDRP (r=0.94, P<0.0001).Conclusion:In conclusion, our results show that the iRBDRP is an early manifestation of the PDRP. Expression of both PDRP and iRBDRP was higher in patients with a more severe form of PD (PD-MCI), which indicates that expression of the two patterns increases with disease severity

    Caffeine and Placebo Improved Maximal Exercise Performance Despite Unchanged Motor Cortex Activation and Greater Prefrontal Cortex Deoxygenation

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    Caffeine (CAF) is an ergogenic aid used to improve exercise performance. Independent studies have suggested that caffeine may have the ability to increase corticospinal excitability, thereby decreasing the motor cortex activation required to generate a similar motor output. However, CAF has also been suggested to induce a prefrontal cortex (PFC) deoxygenation. Others have suggested that placebo (PLA) may trigger comparable effects to CAF, as independent studies found PLA effects on motor performance, corticospinal excitability, and PFC oxygenation. Thus, we investigated if CAF and CAF-perceived PLA may improve motor performance, despite the likely unchanged MC activation and greater PFC deoxygenation. Nine participants (26.4 ± 4.8 years old, VO2MAX of 42.2 ± 4.6 mL kg-1 min-1) performed three maximal incremental tests (MITs) in control (no supplementation) and ∼60 min after CAF and PLA ingestion. PFC oxygenation (near-infrared spectroscopy at Fp1 position), MC activation (EEG at Cz position) and vastus lateralis and rectus femoris muscle activity (EMG) were measured throughout the tests. Compared to control, CAF and PLA increased rectus femoris muscle EMG (P = 0.030; F = 2.88; d = 0.84) at 100% of the MIT, and enhanced the peak power output (P = 0.006; F = 12.97; d = 1.8) and time to exhaustion (P = 0.007; F = 12.97; d = 1.8). In contrast, CAF and PLA did not change MC activation, but increased the PFC deoxygenation as indicated by the lower O2Hb (P = 0.001; F = 4.68; d = 1.08) and THb concentrations (P = 0.01; F = 1.96; d = 0.7) at 80 and 100% the MIT duration. These results showed that CAF and CAF-perceived PLA had the ability to improve motor performance, despite unchanged MC activation and greater PFC deoxygenation. The effectiveness of CAF as ergogenic aid to improve MIT performance was challenged

    Fully Automatic Expression-Invariant Face Correspondence

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    We consider the problem of computing accurate point-to-point correspondences among a set of human face scans with varying expressions. Our fully automatic approach does not require any manually placed markers on the scan. Instead, the approach learns the locations of a set of landmarks present in a database and uses this knowledge to automatically predict the locations of these landmarks on a newly available scan. The predicted landmarks are then used to compute point-to-point correspondences between a template model and the newly available scan. To accurately fit the expression of the template to the expression of the scan, we use as template a blendshape model. Our algorithm was tested on a database of human faces of different ethnic groups with strongly varying expressions. Experimental results show that the obtained point-to-point correspondence is both highly accurate and consistent for most of the tested 3D face models
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