Selección óptima del factor de ajuste CA-CFAR para clutter marino de potencia K estadísticamente variable

The presence of the sea clutter interfering signal sets limitations on the quality of radar detection in coastal and ocean environments. The CA-CFAR processor is the classic solution for detecting radar targets. It usually operates keeping constant its adjustment factor during the entire operation period. As a consequence, the scheme does not take into account the slow statistical variations of the background signal when performing the clutter discrimination. To solve this problem, the authors conducted an intensive processing of 40 million computer generated clutter power samples in MATLAB. As a result, they found the optimal adjustment factor values to be applied in 40 possible clutter statistical states, suggesting thus the use of the CA-CFAR architecture with a variable adjustment factor. In addition, a curve fitting procedure was performed, obtaining mathematical expressions that generalize the results for the whole addressed range of clutter statistical states. The experiments were executed with a 64 cells CA-CFAR and found the adjustment factor values for three common false alarms probabilities. The K distribution was used as clutter model, thanks to its wide popularity. This paper facilitates the handling of the K power distribution avoiding the use of Gamma and Bessel functions, commonly found in developments related to the K model. Moreover, requirements for building an adaptive clutter detector in K power clutter with a priori knowledge of the shape parameter were fulfill. Also, several recommendations are given to continue the development of a more overall solution which will also include the estimation of the shape parameter.La presencia de la señal interferente de clutter marino establece limitaciones en la calidad de la detección de radar en ambientes costeros y de alta mar. El procesador CA-CFAR es la solución clásica para detectar blancos de radar. Usualmente mantiene su factor de ajuste constante todo el período de operación. Como consecuencia, el esquema no toma en consideración las variaciones estadísticas de la señal de fondo cuando realiza la discriminación del clutter. Para resolver este problema, los autores realizaron un procesamiento intensivo de 40 millones de muestras de clutter de intensidad, generadas en computadora a través de MATLAB. Como resultado, encontraron los valores óptimos del factor de ajuste a ser aplicados para 40 posibles estados estadísticos del clutter, sugiriendo el uso de la arquitectura CA-CFAR con un factor de ajuste variable. Adicionalmente, fue llevado a cabo un ajuste de curvas, obteniéndose expresiones matemáticas que generalizan los resultados en todo el intervalo de considerado de estados estadísticos del clutter. Los experimentos se ejecutaron con un CA-CFAR de 64 celdas y apuntaron a encontrar los valores del factor de ajuste para tres probabilidades de falsa alarma comunes. La distribución K fue elegida como el modelo usado para el clutter, gracias a su amplia popularidad. Este artículo facilita el manejo de la distribución K de intensidad, evitando el uso de funciones Gamma y Bessel, comúnmente encontradas en desarrollos relacionados con el modelo K. Además, fueron cumplidos los requerimientos necesarios para construir un detector adaptativo en clutter de potencia K con conocimiento previo del parámetro de forma. Al mismo tiempo, fueron dadas varias recomendaciones para continuar el desarrollo de una solución más general que también incluirá la estimación del parámetro de forma

Detector CFAR de promediación con corrección del factor de ajuste a través del método de los momentos para la distribución Log-Normal

The new LN-MoM-CA-CFAR detector is introduced, exhibiting a reduced deviation of the operational false alarm probability from the value conceived in the design. The solution solves a fundamental problem of CFAR processors that has been ignored in most proposals. Indeed, most of the previously proposed schemes deal with sudden changes in the clutter level, whereas the new solution has an improved performance against slow statistical changes that occur in the background signal. It has been proven that these slow changes have a remarkable influence on the selection of the CFAR adjustment factor, and consequently in maintaining the false alarm probability. The authors took advantage of the high precision achieved by the MoM (Method of Moments) in the estimation of the Log-Normal (LN) shape parameter, and the wide application of this distribution to radar clutter modeling, to create an architecture that offers precise results and it’s computationally inexpensive at the same time. After an intensive processing, involving 100 million Log-Normal samples, a scheme, which operates with excellent stability reaching a deviation of only 0,2884 % for the probability of false alarm of 0,01, was created, improving the classical CA-CFAR detector through the continuous correction of its scale factor.Se presenta el nuevo detector LN-MoM-CA-CFAR que tiene una desviación reducida en la tasa de probabilidad de falsa alarma operacional con respecto al valor concebido de diseño. La solución corrige un problema fundamental de los procesadores CFAR que ha sido ignorado en múltiples desarrollos. En efecto, la mayoría de los esquemas previamente propuestos tratan con los cambios bruscos del nivel del clutter mientras que la presente solución corrige los cambios lentos estadísticos de la señal de fondo. Se ha demostrado que estos tienen una influencia marcada en la selección del factor de ajuste multiplicativo CFAR, y consecuentemente en el mantenimiento de la probabilidad de falsa alarma. Los autores aprovecharon la alta precisión que se alcanza en la estimación del parámetro de forma Log-Normal con el MoM, y la amplia aplicación de esta distribución en la modelación del clutter, para crear una arquitectura que ofrece resultados precisos y con bajo costo computacional. Luego de un procesamiento intensivo de 100 millones de muestras Log-Normal, se creó un esquema que, mejorando el desempeño del clásico CA-CFAR a través de la corrección continua de su factor de ajuste, opera con una excelente estabilidad alcanzando una desviación de solamente 0,2884 % para la probabilidad de falsa alarma de 0,01

Caracterização de Doentes com Espondilite Anquilosante em Hidrocinesiterapia – Uma Avaliação Multidimensional

OBJECTIVES: Clinical, functional and working characterization of an Ankylosing Spondylitis (AS) group of patients that perform hydrotherapy regularly in a physical and rehabilitation department. Assessment of the benefit of hydrotherapy in symptom relief, function and consumption of analgesics and non-steroidal anti-inflammatory drugs (NSAIDs). MATERIAL AND METHODS: A transversal characterization of a group of patients with SA undergoing hydrotherapy was performed. Demographic, clinical (including disease activity, function and health-related quality of life), radiographic and laboratorial data was collected. A questionnaire about working situation, presence of dyspnoea, smoking, number of sessions and benefit of hydrotherapy was applied. RESULTS: 22 patients (73% males) were enrolled in the study, mean age 55.6 ± 8.8 years, mean duration of the disease 28.0 ± 13.13 years. Apart from the axial involvement, 50% had a previous history of enthesitis, 54.5% peripheral arthritis, 18% dactylitis and 36% uveitis. At the day of assessment, 81% had low-back pain complaints (39% inflammatory rhythm), 18% oligoarthritis, 9.1% had total hip and/or knee prosthesis. The majority of the patients had active disease, accentuated functional deterioration and reduced health related quality of life. About 54.5% were retired due to disability, 18.2% were smokers and 36.4% had dyspnoea; 31.8% presented restrictive ventilatory alterations; 36.4% obstructive (predominance in the small airways); 13.6% mixed and in 18.2% the spiromety was normal. The mean total time of hydrotherapy was 13 ± 6.8 years. The patients attended a mean of 3 sessions per week and 3 series of 15 sessions per year. Of the 22.7% that performed another physical activity, 80% walked and 20% cycled. The ingestions of analgesics (p < 0.05) and NSAIDs (p < 0.01) were also reduced. CONCLUSION: A high percentage of spyrometric changes were identified. The majority of the patients are retired due to disability. The patients feel benefit with hydrotherapy, that contributed to reduction of the analgesic and NSAIDs consumption. The importance of the global systemic evaluation and multidisciplinary of the SA to optimize the therapeuthics and improve the quality of life of the patients is pointed out

ONDE ESTÃO OS EGRESSOS DO CURSO DE ADMINISTRAÇÃO DA UFSC?

O Estudo de Caso aborda a atuação profissional de egressos, modalidade presencial, do Curso de Administração (2011-2014), da Universidade Federal de Santa Catarina (CAD-UFSC). Da população de 548 bacharéis da lista de Graduados deste Survey, obteve-se a Amostra de 146 investigados, num Intervalo de Confiança de 95% e Erro Amostral de 7% (RENDER, STAIR JR.; HANNA, 2010). O questionário foi estruturado com perguntas fechadas Estilo Likert (HAIR JR., ANDERSON; TATHAM; BLACK, 2005), fixado no Google Docs e enviado por e-mail a todos egressos do período. A coleta foi feita em maio e junho de 2015, o tratamento dos dados foi quantitativo e usou-se o SPSS® na sua operacionalização. A pesquisa apontou que predominam os egressos na faixa etária de 26 a 30 anos (50,7%), sendo 50,7% do sexo feminino, a maioria natural do Estado de Santa Catarina, cursaram o ensino médio em escola privada e que cerca de 30% fez intercâmbio no exterior durante a graduação. Eles trabalham em empresas de médio porte e a faixa salarial predominante oscila de 3 a 6 salários mínimos, mas a maioria deles fez ou está cursando pós-graduação. Realçam à relevância em terem se graduado na UFSC, pois lhes permitiu reconhecimento pessoal e profissional, reforçando as avaliações do CAD-UFSC como um dos cursos 5 estrelas pelo MEC-Brasil

The Faber-Jackson relation for early-type galaxies: Dependence on the magnitude range

We take a sample of early-type galaxies from the Sloan Digital Sky Survey (SDSS-DR7, $\sim$ 90 000 galaxies) spanning a range of approximately 7 $mag$ in both $g$ and $r$ filters and analyse the behaviour of the Faber-Jackson relation parameters as functions of the magnitude range. We calculate the parameters in two ways: i) We consider the faintest (brightest) galaxies in each sample and we progressively increase the width of the magnitude interval by inclusion of the brighter (fainter) galaxies (increasing-magnitude-intervals), and ii) we consider narrow-magnitude intervals of the same width ($\Delta M = 1.0$ $mag$) over the whole magnitude range available (narrow-magnitude-intervals). Our main results are that: i) in both increasing and narrow-magnitude-intervals the Faber-Jackson relation parameters change systematically, ii) non-parametric tests show that the fluctuations in the values of the slope of the Faber-Jackson relation are not products of chance variations. We conclude that the values of the Faber-Jackson relation parameters depend on the width of the magnitude range and the luminosity of galaxies within the magnitude range. This dependence is caused, to a great extent by the selection effects and because the geometrical shape of the distribution of galaxies on the $M - \log (\sigma_{0})$ plane depends on luminosity. We therefore emphasize that if the luminosity of galaxies or the width of the magnitude range or both are not taken into consideration when comparing the structural relations of galaxy samples for different wavelengths, environments, redshifts and luminosities, any differences found may be misinterpreted.Comment: 15 pages, 5 figures. A&A. Accepte

Divergent Effects of Metformin on an Inflammatory Model of Parkinson’s Disease

The oral antidiabetic drug metformin is known to exhibit anti-inflammatory properties through activation of AMP kinase, thus protecting various brain tissues as cortical neurons, for example. However, the effect of metformin on the substantia nigra (SN), the main structure affected in Parkinson’s disease (PD), has not yet been studied in depth. Inflammation is a key feature of PD and it may play a central role in the neurodegeneration that takes place in this disorder. The aim of this work was to determine the effect of metformin on the microglial activation of the SN of rats using the animal model of PD based on the injection of the pro-inflammogen lipopolysaccharide (LPS). In vivo and in vitro experiments were conducted to study the activation of microglia at both the cellular and molecular levels. Our results indicate that metformin overall inhibits microglia activation measured by OX-6 (MHCII marker), IKKβ (pro-inflammatory marker) and arginase (anti-inflammatory marker) immunoreactivity. In addition, qPCR experiments reveal that metformin treatment minimizes the expression levels of several pro- and anti-inflammatory cytokines. Mechanistically, the drug decreases the phosphorylated forms of mitogen-activated protein kinases (MAPKs) as well as ROS generation through the inhibition of the NADPH oxidase enzyme. However, metformin treatment fails to protect the dopaminergic neurons of SN in response to intranigral LPS. These findings suggest that metformin could have both beneficial and harmful pharmacological effects and raise the question about the potential use of metformin for the prevention and treatment of PD.España MINECO SAF2015-64171-

Prevalence Of Temporomandibular Disorders In Postmenopausal Women And Relationship With Pain And Hrt

The prevalence of temporomandibular disorders (TMD) is higher in females, reaching their high peak during reproductive years, probably because of the action of some female hormones, which alter pain threshold. This study aimed to investigate the prevalence of TMD in postmenopausal women and its relationship with pain and hormone replacement therapy (HRT). In total, 284 patients were evaluated and classified using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Pain was measured using the Visual Analogue Scale (VAS), and patients were also asked about the use of HRT. All data was analyzed using analysis of variance (ANOVA) and chi-square test. In total, 155 subjects did not have TMD and 129 had TMD; TMD group patients were classified according to RDC/TMD axis I classification as follows: muscle disorder group (1.6%), disk displacement group (72.87%), and arthralgia, osteoarthritis, and osteoarthrosis group (37.98%). Pain was registered in 35 patients who belonged to the TMD group, while 48 patients reported the use of HRT. There was a similar percentage of TMD and non TMD patients; moreover, the use of exogenous hormones was no associated with TMD, suggesting that there is no influence on the pain threshold.30

Trends and topics in geographically weighted regression research from 1996 to 2019

[EN]This research was conducted in order to improve the understanding of the struc-ture, contents, and trend of topics within the existing literature in the field of geographically weighted regression. Additionally, it intended to determine and produce a mapping of scientific networks in the domain of geographically weighted regression. The proposed methodology implements a combination of bibliometric techniques and modelling of topics in order to extract the latent top-ics from the collected literature by utilising latent Dirichlet allocation and a ma-chine learning tool. The results identified the most prolific authors, the most cited authors, the most representative articles and journals, and the countries which are responsible for the publication

GeoWeightedModel : An R-Shiny package for Geographically Weighted Models

[EN]This paper describes GeoWeightedModel, a R package, which provides a graphical user friendly web application to perform techniques from a subarea of spatial Statistics known as Geographically Weighted (GW) models, such as Geographically Weighted Regression (GWR) and its extensions: Robust GWR, Generalized GWR, Heteroskedastic GWR, Mixed GWR, and “Scalable​ GWR), Geographically Weighted Principal Component Analysis, and Geographically Weighted Discriminant analysis. It also allows calculating a basic and robust Geographically weighted summary. The main goal of GeoWeightedModel package was to make the workflow easier to use, especially for those who are not familiar with the R environment. With GeoWeightedModel, analyses can be performed interactively (point-and-click way) in a web browser, making the applications easier for many more researchers. In addition with this tool, the results of the analyses can be mapped providing a valuable tool for exploring the spatial heterogeneity of the data