Fast gain calibration in radio astronomy using alternating direction implicit methods: Analysis and applications

Context. Modern radio astronomical arrays have (or will have) more than one order of magnitude more receivers than classical synthesis arrays, such as the VLA and the WSRT. This makes gain calibration a computationally demanding task. Several alternating direction implicit (ADI) approaches have therefore been proposed that reduce numerical complexity for this task from $\mathcal{O}(P^3)$ to $\mathcal{O}(P^2)$, where $P$ is the number of receive paths to be calibrated. Aims. We present an ADI method, show that it converges to the optimal solution, and assess its numerical, computational and statistical performance. We also discuss its suitability for application in self-calibration and report on its successful application in LOFAR standard pipelines. Methods. Convergence is proved by rigorous mathematical analysis using a contraction mapping. Its numerical, algorithmic, and statistical performance, as well as its suitability for application in self-calibration, are assessed using simulations. Results. Our simulations confirm the $\mathcal{O}(P^2)$ complexity and excellent numerical and computational properties of the algorithm. They also confirm that the algorithm performs at or close to the Cramer-Rao bound (CRB, lower bound on the variance of estimated parameters). We find that the algorithm is suitable for application in self-calibration and discuss how it can be included. We demonstrate an order-of-magnitude speed improvement in calibration over traditional methods on actual LOFAR data. Conclusions. In this paper, we demonstrate that ADI methods are a valid and computationally more efficient alternative to traditional gain calibration method and we report on its successful application in a number of actual data reduction pipelines.Comment: accepted for publication in Astronomy & Astrophysic

EFEITOS DA VINHOTERAPIA EM PARÂMETROS SANGUÍNEOS. (COLESTEROL, GLICOSE E TRIGLICERÍDEOS)

É expressivo o número de evidências acerca das propriedades benéficas do vinho para a saúde humana. Estudos recentes comprovaram que certas substâncias presentes no vinho, os compostos fenólicos, possuem atividade antioxidante inibindo a oxidação do LDL - Colesterol. Além da ação antioxidante, mecanismos antiplaquetários, antiinflamatórios e vasodilatadores. Segundo estudos, o etanol eleva os níveis sangüíneos de HDL - Colesterol também faz parte das propriedades do vinho. Entretanto, por ser uma bebida alcoólica, é importante ressaltar que o vinho deve ser consumido com moderação, sendo que o consumo excessivo passa a ser fator de diversas doenças. O presente estudo analisou trinta pacientes com alimentação normal, ingerindo vinho tinto Cabernet Sauvignon, Isabel e Chardonnay durante a refeição principal, num período de trinta dias, acompanhado por exames sanguíneos: colesterol total, HDL- Colesterol, LDL- Colesterol, triglicerídeos e glicemia pré-vinho e pós-vinho. Com relação aos exames laboratoriais estes apresentaram um aumento significativo no HDL - Colesterol (p<0,05) apenas com o grupo que teve a ingestão do vinho Isabel

Horizontal polarization of ground motion in the Hayward fault zone

We investigate shear wave polarization in the Hayward fault zone near Niles Canyon, Fremont, CA. Waveforms of 12 earthquakes recorded by a seven-accelerometer seismic array around the fault are analysed to clarify directional site effects in the fault damage zone. The analysis is performed in the frequency domain through H/V spectral ratios with horizontal components rotated from 0◦ to 180◦, and in the time domain using the eigenvectors and eigenvalues of the covariance matrix method employing three component records. The near-fault ground motion tends to be polarized in the horizontal plane. At two on-fault stations where the local strike is N160◦, ground motion polarization is oriented N88 ± 19◦ and N83 ± 32◦, respectively. At a third on-fault station, the motion is more complex with horizontal polarization varying in different frequency bands. However, a polarization of N86 ± 7◦, similar to the results at the other two on-fault stations, is found in the frequency band 6–8 Hz. The predominantly high-angle polarization from the fault strike at the Hayward Fault is consistent with similar results at the Parkfield section of the San Andreas Fault and the Val d’Agri area (a Quaternary extensional basin) in Italy. In all these cases, comparisons of the observed polarization directions with models of fracture orientation based on the fault movement indicate that the dominant horizontal polarization is near-orthogonal to the orientation of the expected predominant cracking direction. The results help to develop improved connections between fault mechanics and near-fault ground motion

The evolution of eyes and visually guided behaviour

The morphology and molecular mechanisms of animal photoreceptor cells and eyes reveal a complex pattern of duplications and co-option of genetic modules, leading to a number of different light-sensitive systems that share many components, in which clear-cut homologies are rare. On the basis of molecular and morphological findings, I discuss the functional requirements for vision and how these have constrained the evolution of eyes. The fact that natural selection on eyes acts through the consequences of visually guided behaviour leads to a concept of task-punctuated evolution, where sensory systems evolve by a sequential acquisition of sensory tasks. I identify four key innovations that, one after the other, paved the way for the evolution of efficient eyes. These innovations are (i) efficient photopigments, (ii) directionality through screening pigment, (iii) photoreceptor membrane folding, and (iv) focusing optics. A corresponding evolutionary sequence is suggested, starting at non-directional monitoring of ambient luminance and leading to comparisons of luminances within a scene, first by a scanning mode and later by parallel spatial channels in imaging eyes

Radioisotopic purity and imaging properties of cyclotron-produced 99mTc using direct 100Mo(p,2n) reaction

Evaluation of the radioisotopic purity of technetium-99m (99mTc) produced in GBq amounts by proton bombardment of enriched molibdenum-100 (100Mo) metallic targets at low proton energies (i.e. within 15\u201320 MeV) is conducted. This energy range was chosen since it is easily achievable by many conventional medical cyclotrons already available in the nuclear medicine departments of hospitals. The main motivation for such a study is in the framework of the research activities at the international level that have been conducted over the last few years to develop alternative production routes for the most widespread radioisotope used in medical imaging. The analysis of technetium isotopes and isomeric states (9xTc) present in the pertechnetate saline Na99mTcO4 solutions, obtained after the extraction/purification procedure, reveals radionuclidic purity levels basically in compliance with the limits recently issued by European Pharmacopoeia 9.3 (2018 Sodium pertechnetate (99mTc) injection 4801\u20133). Moreover, the impact of 9xTc contaminant nuclides on the final image quality is thoroughly evaluated, analyzing the emitted high-energy gamma rays and their influence on the image quality. The spatial resolution of images from cyclotron-produced 99mTc acquired with a mini-gamma camera was determined and compared with that obtained using technetium-99m solutions eluted from standard 99Mo/99mTc generators. The effect of the increased image background contribution due to Compton-scattered higher-energy gamma rays (E \u3b3 \u2009\u2009>\u2009\u2009200\u2009keV), which could cause image-contrast deterioration, was also studied. It is concluded that, due to the high radionuclidic purity of cyclotron-produced 99mTc using 100Mo(p,2n)99mTc reaction at a proton beam energy in the range 15.7\u201319.4 MeV, the resulting image properties are well comparable with those from the generator-eluted 99mTc

Plasma 25-Hydroxyvitamin D Concentration and Risk of Incident Type 2 Diabetes in Women

OBJECTIVE — To determine the association between 25-hydroxyvitamin D (25-OHD) con-centration and risk of incident type 2 diabetes. RESEARCH DESIGN AND METHODS — In a nested case-control study conducted among 608 women with newly diagnosed type 2 diabetes and 559 control subjects in the Nurses’ Health Study, we measured the association between baseline plasma 25-OHD concentration and risk of incident diabetes. RESULTS — After adjusting for matching factors and diabetes risk factors, including BMI, higher levels of plasma 25-OHD were associated with a lower risk for type 2 diabetes. The odds ratio for incident type 2 diabetes in the top (median 25-OHD, 33.4 ng/ml) versus the bottom (median 25-OHD, 14.4 ng/ml) quartile was 0.52 (95 % CI 0.33–0.83). The associations were consistent across subgroups of baseline BMI, age, and calcium intake. CONCLUSIONS — Plasma 25-OHD concentration was associated with lower risk of inci-dent type 2 diabetes in women. Diabetes Care 33:2021–2023, 2010 G rowing evidence indicates that sub-optimal vitamin D status may play arole in the development of type 2 diabetes (1). Results from longitudinal observational studies support the hypoth-esis that low vitamin D status is associated with development of type 2 diabetes; however, only one study has examined the association between blood 25-hydroxyvitamin D (25-OHD) concentra-tion and incident type 2 diabetes, and there was no significant association among women (2,3). We examined pro-spectively the association between plasma 25-OHD concentration and risk of inci-dent type 2 diabetes among women in a case-control study nested within th

Cancer Stem Cells Sensitivity Assay (STELLA) in Patients with Advanced Lung and Colorectal Cancer: A Feasibility Study.

Cancer stem cells represent a population of immature tumor cells found in most solid tumors. Their peculiar features make them ideal models for studying drug resistance and sensitivity. In this study, we investigated whether cancer stem cells isolation and in vitro sensitivity assay are feasible in a clinical setting. METHODS: Cancer stem cells were isolated from effusions or fresh cancer tissue of 23 patients who progressed after standard therapy failure. Specific culture conditions selected for immature tumor cells that express markers of stemness. These cells were exposed in vitro to chemotherapeutic and targeted agents. RESULTS: Cancer stem cells were extracted from liver metastases in 6 cases (25%), lung nodules in 2 (8%), lymph node metastases in 3 (12.5%) and pleural/peritoneal/pericardial effusion in 13 (54%). Cancer stem cells were successfully isolated in 15 patients (63%), including 14 with lung cancer (93.3%). A sensitivity assay was successfully performed in 7 patients (30.4%), with a median of 15 drugs/combinations tested (range 5-28) and a median time required for results of 51 days (range 37-95). CONCLUSION: The approach used for the STELLA trial allowed isolation of cancer stem cells in a consistent proportion of patients. The low percentage of cases completing the full procedure and the long median time for obtaining results highlights the need for a more efficient procedure. TRIAL REGISTRATION: ClinalTrials.gov NCT01483001

Avaliação da amplitude articular do joelho: correlação entre as medidas realizadas com o goniômetro universal e no dinamômetro isocinético

CONTEXTUALIZAÇÃO: O instrumento mais utilizado pelos terapeutas para mensuração da amplitude de movimento (ADM) articular é o goniômetro universal. No entanto, há carência de estudos que analisem a confiabilidade das medidas da ADM do joelho realizadas no dinamômetro isocinético. OBJETIVO: O objetivo deste estudo foi analisar a correlação entre as medidas de ADM na articulação do joelho, realizadas com o goniômetro universal e no dinamômetro isocinético. MÉTODO: Foram avaliados 38 voluntários saudáveis (27 mulheres, 11 homens), com idade de 36 ± 11 anos, com limitação mínima de 20° na ADM de extensão do joelho. No membro dominante de cada sujeito foram realizadas três mensurações da ADM do joelho com o goniômetro e três mensurações no dinamômetro. RESULTADOS: Os resultados deste estudo mostraram que há alto grau de correlação entre as medidas da ADM do joelho obtidas com o goniômetro universal e no dinamômetro isocinético (Coeficiente de Correlação de Pearson = 0,90). CONCLUSÃO: Com os procedimentos realizados, tanto o goniômetro universal como o dinamômetro isocinético podem ser utilizados para avaliação da ADM do joelho, pois ambos apresentam mensurações confiáveis.<br>BACKGROUND: The instrument most often used by therapists for measuring joint range of motion (ROM) is the universal goniometer. However, there is a lack of studies analyzing the reliability of knee joint ROM measured by the isokinetic dynamometer. OBJECTIVE: The purpose of this study was to analyze the correlation between the knee joint ROM measurements made using a universal goniometer and an isokinetic dynamometer. METHOD: 38 healthy volunteers (27 women, 11 men) aged 36 ± 11 years were evaluated. All of them had a minimum knee extension ROM limitation of 20°. Three knee ROM measurements were made using the universal goniometer and another three using the isokinetic dynamometer, on each subject's dominant limb. RESULTS: The results showed a high degree of correlation between the knee ROM measurements made using the two instruments (Pearson correlation coefficient = 0.90). CONCLUSION: From the procedures performed, both the universal goniometer and the isokinetic dynamometer can be used to evaluate knee ROM, since they both present reliable measurements