Perfil profissional no meio rural: subsídios para diagnóstico e definição de estratégias: cadeias produtivas da apicultura, bovinocultura leiteira e ovinocultura.

bitstream/CNPDIA-2009-09/12002/1/DOC40_2008.pd

Diagnostic accuracy of multislice computed tomography coronary angiography is improved at low heart rates

Purpose: Assess the effect of heart rate on diagnostic accuracy for the detection of significant coronary artery stenosis using 16-row multislice computed tomography (MSCT). Material and methods: About 120 patients (105 males; 59 ± 11 years) with suspected coronary artery disease who underwent conventional coronary angiography (CA) and MSCT-CA were retrospectively enrolled for the study. Patients underwent a MSCT-CA (Sensation 16, Siemens, Germany), with the following protocol: Collimation 16 × 0.75 mm, gantry rotation time 420 ms, feed/rotation 3.0 mm, kV 120, mAs 400-500. The protocol for contrast material administration was 100 ml of Iodixanol (Visipaque 320 mg l/ml, Amersham, UK) at 4 ml/s and the delay was defined with a bolus tracking technique. In all patients the mean heart rate (HR) during the scan was used as a criteria to divide the population in two groups of 60 patients each. In one group (Low HR) the 60 patients with lower heart rates, and in the other group (High HR) the patients with higher heart rates. In the two groups diagnostic accuracy (per coronary segment) for the detection of significant stenosis (≥50% lumen reduction) was evaluated in vessels ≥2 mm of diameter using quantitative CA as reference standard. The difference in diagnostic accuracy were compared with a Chi2 test and a p < 0.05 was considered significant. Results: There was no significant difference between the two groups regarding age, gender, weight, mean intravascular attenuation, and calcium score. Overall 1310 (652 for Low HR and 658 for High HR) segments with 219 (105 for Low HR and 114 for High HR) significant lesions were available for the analysis. The average heart rate was 52 ± 4HU and 63 ± 5HU for Low HR and High HR, respectively (p < 0.001). The sensitivity and specificity were 92 and 96% for Low HR and 90 and 92% for High HR (p < 0.05). There were 22 vs. 44 false positives, and 8 vs. 12 false negatives in the Low HR and High HR, respectively. Conclusion: Increasing HR significantly deteriorates diagnostic accuracy in MSCT-CA

Análise comparativa entre arranjos de tomografia elétrica no reconhecimento de estruturas de fluxo em aquífero fraturado em Caçapava do Sul (RS)

This paper performs presents a comparative analysis between data from detailed electrical resistivity tomography data acquired through the dipole-dipole, Schlumberger and Wenner arrays of detail, obtained on a ground where granite terrain in Caçapava do Sul (RS) where groundwater flows in occurs underground flow in a fractured aquifer system, acquired through the arrangements make dipole-dipole, Schlumberger and Wenner. Structural data obtained on rocks exposed in 100 m and 300 m offrom the study area served as a fundamental the basis for analysisthe analysis of geophysical products and the definition of the mathematical model that is more feasible with the reality. The predominant fracture direction in the region has E/W orientation with two main senses of diving.By the results of the three arrays, it was possible to recognize areas of low resistivity related to water accumulation, with values lower than 70 Ω.m, in contrast to values higher than 1000 Ω.m typical of unaltered rock. The results of the arrangement allowed Schlumberger array allowed a 3D modeling a surface of low resistivity surface with orientation and dive compatible with the fracture system recognized in field, ih this way this array showed a more realist model guidance and diving are compatible with systems of fractures found in rock, to the of the geological structures in detriment to the other results, which do not allow subsidies for an adequate definition of sites for drilling wells. Este trabalho apresenta uma análise comparativa entre dados de tomografia elétrica de detalhe, obtidos sobre terreno granítico onde ocorre fluxo subterrâneo em sistema aquífero fraturado, adquiridos por meio dos arranjos dipolo-dipolo, Schlumberger e Wenner, na região de Caçapava do Sul (RS). Dados estruturais obtidos em exposições de rochas entre 100 m e 300 m da área de estudo serviram de base para análise dos produtos geofísicos e definição do modelo matemático mais factível a realidade geológica. O fraturamento predominante na região possui orientação E/W com dois sentidos principais de mergulho. Nos três arranjos de aquisição tomográfica analisados, foi possível o reconhecimento de zonas de baixa resistividade relacionadas ao acúmulo de água, com valores inferiores a 70 W.m, em contraste com valores superiores a 1000 W.m típicos de rocha inalterada. Os resultados referentes ao arranjo Schlumberger permitiram o modelamento 3D de uma superfície de baixa resistividade com orientação e mergulho compatíveis com sistemas de fraturas reconhecidos em afloramentos, em detrimento aos demais resultados, que não possibilitaram subsídios para uma definição adequada de locais para perfuração de poços

Equatorial Atlantic Ocean dynamics in a coupled ocean–atmosphere model simulation

The ocean temperatures and zonal currents at the equatorial Atlantic simulated by an improved version of the Brazilian earth system model (BESM), with changes in the cloud cover scheme and optical properties of the atmospheric component, are analyzed and compared to those obtained from a previous version of BESM and also from other seven selected CMIP5 models. It is shown that this updated version of BESM, despite some persistent biases, more accurately represents the surface temperature variation at the Equator and the equatorial thermocline east–west slope. These improvements are associated to a more realistic seasonal cycle achieved for the Atlantic equatorial undercurrent, as well as sea surface temperatures and zonal wind stress. The better simulation of the equatorial undercurrent is, in its turn, credited to a more realistic representation of the surface wind position and strength at the tropical Atlantic by the coupled model. With many of the systematic errors noticed in the previous version of the model alleviated, this version of BESM can be considered as a useful tool for modelers involved in Atlantic variability studies

A highly-compact and ultra-fast homogeneous electromagnetic calorimeter based on oriented lead tungstate crystals

Progress in high-energy physics has been closely tied to the development of high-performance electromagnetic calorimeters. Recent experiments have demonstrated the possibility to significantly accelerate the development of electromagnetic showers inside scintillating crystals typically used in homogeneous calorimeters based on scintillating crystals when the incident beam is aligned with a crystallographic axis to within a few mrad. In particular, a reduction of the radiation length has been measured when ultrarelativistic electron and photon beams were incident on a high-Z scintillator crystal along one of its main axes. Here, we propose the possibility to exploit this physical effect for the design of a new type of compact e.m. calorimeter, based on oriented ultra-fast lead tungstate (PWO-UF) crystals, with a significant reduction in the depth needed to contain electromagnetic showers produced by high-energy particles with respect to the state-of-the-art. We report results from tests of the crystallographic quality of PWO-UF samples via high-resolution X-ray diffraction and photoelastic analysis. We then describe a proof-of-concept calorimeter geometry defined with a Geant4 model including the shower development in oriented crystals. Finally, we discuss the experimental techniques needed for the realization of a matrix of scintillator crystals oriented along a specific crystallographic direction. Since the angular acceptance for e.m. shower acceleration depends little on the particle energy, while the decrease of the shower length remains pronounced at very high energy, an oriented crystal calorimeter will open the way for applications at the maximum energies achievable in current and future experiments. Such applications span from forward calorimeters, to compact beam dumps for the search for light dark matter, to source-pointing space-borne γ-ray telescopes, to decrease the size and the cost of the calorimeter needed to fully contain e.m. showers initiated by GeV to TeV particles