Gain and noise spectral density in an electronic parametric amplifier with added white noise

In this paper, we discuss the behavior of a linear classical parametric amplifier (PA) in the presence of white noise and give theoretical estimates of the noise spectral density based on approximate Green's functions obtained by using averaging techniques. Furthermore, we give analytical estimates for parametric amplification bandwidth of the amplifier and for the noisy precursors to instability. To validate our theory we compare the analytical results with experimental data obtained in an analog circuit. We describe the implementation details and the setup used in the experimental study of the amplifier. Near the threshold to the first parametric instability, and in degenerate-mode amplification, the PA achieved very high gains in a very narrow bandwidth centered on its resonance frequency. In quasi-degenerate mode amplification, we obtained lower values of gain, but with a wider bandwidth that is tunable. The experimental data were accurately described by the predictions of the model. Moreover, we noticed spectral components in the output signal of the amplifier which are due to noise precursors of instability. The position, width, and magnitude of these components are in agreement with the noise spectral density obtained by the theory proposed here

Intensity-duration-frequency of maximum rainfall in Mato Grosso State.

EN-US: Intensive rainfall is an important meteorological variable that is of technical interest in hydraulic projects. This study therefore generated Intensity-Duration-Frequency equations (IDF) for 14 weather stations in Mato Grosso State, based on pluviograph analysis. Annual maximum rainfall data regarding 10-to-1440-minute long rainfall events were collected from digitized daily pluviographs. Data adherence to the generalized extreme value distribution (GEV) was checked through the Kolmogorov-Smirnov test at a 20% significance level. Next, the maximum probable rainfall for return periods such as 2, 5, 10, 20, 30, 50 and 100 years was calculated and the IDF equations were adjusted. The performance of the IDF equations was evaluated based on mean absolute error (MAE), root mean square error (RMSE), bias, Willmott's concordance index and Nash-Sutcliffe efficiency index (ENS). Adjusting the IDF equations was only possible for rainfall durations ranging from 10 to 360 min at each station due to the low frequency of longer rainfalls. High variation was present in parameters of the IDF equation and in maximum rainfall intensity between stations. The satisfactory performance of the models, as attested to by statistical indices, allows using IDF equations adjusted for rainfall durations from 10 to 360 min, and return periods from 2 to 100 years, in the regions of the Mato Grosso weather stations. | PT-BR: A chuva intensa é uma importante variável meteorológica que apresenta interesse técnico em projetos hidráulicos. Assim, este estudo teve como objetivo obter equações intensidade-duração-frequência (IDF), obtidas por análise de pluviógrafos, para 14 estações no Estado do Mato Grosso. As séries anuais de intensidade máximas de chuva com duração de 10 a 1440 min foram obtidas de Pluviogramas diários digitalizados. Verificada a aderência das séries à distribuição generalizada de valores extremos, pelo teste de Kolmogorov-Smirnov à 20% de significância, calculou-se as chuvas máximas prováveis para os tempos de retorno de 2, 5, 10, 20, 30, 50 e 100 anos e, ajustaram-se as equações IDF. O desempenho das equações IDF foi avaliado pelo erro absoluto médio (MAE), erro quadrático médio (RMSE), bias, índice de concordância de Willmott e índice de eficiência de Nash-Sutcliffe (ENS). Em todas as estações foi possível ajustar apenas equações IDF para chuvas com duração de 10 a 360 min, devido à baixa frequência de chuvas com duração superior. Houve grande variação na intensidade máxima da chuva e dos parâmetros da equação IDF entre as estações estudadas. O bom desempenho dos modelos, conforme atestados por índices estatísticos, permitem a utilização das equações IDF para as durações de 10 a 360 min e tempo de retorno de 2 a 100 anos, nas regiões das estações do Mato Grosso

Abordagem multivariada para recomendação de sorgo forrageiro no semiárido cearense.

A decisão de quais culturas forrageiras plantar nas regiões semiáridas brasileira não é um processo fácil, devido as instabilidades climáticas decorrente em cada safra agrícola. Dessa forma, o presente trabalho objetivou-se comparar o desempenho fenotípico de cultivares híbridas e variedades da cultura do sorgo para a produção de forragem com o auxílio do método gráfico para análise multivariada, em região norte cearense. O ensaio foi conduzido envolvendo cultivares tanto de variedades (V) quanto de híbridos simples de sorgo. O delineamento experimental utilizado foi o de bloco ao acaso com três repetições. Foram avaliados 17 caracteres pela análise de variância e posteriormente analisadas pelo método gráfico com análise multivariada, que permitiu uma melhor decisão sobre o desempenho entre as cultivares da cultura quando se consideram grandes quantidades de caracteres. As cultivares de sorgo hibrido BRS 716 e o sorgo BRS 655 apresentam bom desempenho produtivo e nutricional em condições de semiárido

Comportamento ingestivo de caprinos das raças Moxotó e Canindé em confinamento recebendo dois níveis de energia na dieta.

Neste trabalho foi avaliado o comportamento ingestivo de caprinos nativos do semiárido nordestino mantidos em confinamento. Foram utilizados 40 machos castrados, 20 da raça Moxotó e 20 Canindé, com peso médio inicial de 15,22 kg ± 1,78 kg, distribuídos aleatoriamente em delineamento inteiramente casualizado, em arranjo fatorial 2 × 2, com duas raças e duas dietas. Foram avaliadas duas dietas experimentais: uma com menor nível energético (2,2 Mcal de EM/kg de MS), formulada com relação volumoso:concentrado 70:30; e outra com maior nível energético (2,7 Mcal de EM/kg de MS) e relação volumoso:concentrado de 35:65. Para o comportamento ingestivo, foram realizadas observações a cada cinco minutos, durante 24 horas, para determinação do tempo despendido em alimentação, ruminação e ócio. O consumo de matéria seca, o número de bolos ruminados e de mastigações merícicas por dia, o tempo de mastigação merícica por bolo, a frequência urinária e de procura por água e o consumo de água variaram significativamente entre as raças. Os animais da raça Moxotó apresentaram maior frequência urinária e menor procura por água ao longo do dia. Entretanto, recebendo a dieta com 2,7 Mcal de EM/kg de MS, excretaram menor quantidade de urina. Caprinos das raças Moxotó e Canindé são muito seletivos e têm maior preferência pelas partículas pequenas da dieta, independentemente do seu nível energético. O fornecimento de dietas com alto nível de energia favorece a eficiência alimentar e de ruminação de caprinos Moxotó e Canindé em confinamento

Automatized assessment of motor function in patients with NMD: MFM-Digital Study

International audienceGiven the progress of research and management in Spinal Muscular Atrophy (SMA), validated tools are needed to assess patients’ motor function. The Motor Function Measure assessment (MFM) is known as principal outcome measure of the motor function with an international recognition. It is a validated tool and sensitive to the change applicable in SMA.Clinicians from the Neuromuscular Diseases Department (Hospices Civils de Lyon, France) are developing the MFM-digital, an automated system to assess SMA patients’ motor function based on MFM. By using a Microsoft Kinect and a digital tablet, the objective is to improve reliability and acceptability of the MFM by lowering the measure’s subjectivity linked to heteroevaluation and by creating a hybrid serious-game.The feasibility study assesses the relevance of the system to capture postures and motions during a MFM test. Due to technological limits of capture by the Kinect sensor, 14 on 32 items may be recognized by the Kinect and 3 items by a tablet. In each case, the therapist scores items in live by referring to the MFM manual. Based on digital data coming from Kinect and tablet records, the principal investigator informs a blind score. The good correlation between items scoring by a therapist and items scoring on captured digital data show the possibility to use an algorithm to propose an automatic score.21 records of MFM were collected with Kinect and Tablet sensors. The first results are encouraging, showing a good concordance between the scores with tracks of improvements of the system in particular concerning the capture for weaker patients. The data supplied by the MFM-digital system bring additional data, in particular the duration of the items’ exercises and kinematic parameters.One interest of this work consists in creating an automatic measurement tool, based on the MFM-items, which has already shown its validity

Proposta de uma unidade de an?lise para a materialidade da cogni??o.

As aulas de ci?ncias s?o espa?os ocupados por um conjunto enorme de objetos e sem eles as aulas certamente seriam diferentes ou mesmo imposs?veis de acontecer. Assim, p?e-se a necessidade de se considerar o engajamento entre esses objetos e humanos para o entendimento dos processos de ensino/aprendizagem. No presente artigo apresentamos uma proposta de unidade de an?lise, denominada por n?s de figura??o cognitiva. Essa unidade est? fundamentada no enquadramento te?rico-metodol?gico da teoria ator-rede, da cogni??o distribu?da e na psicologia ecol?gica. Com essa proposta, procuramos evitar um vocabul?rio mentalista e cognitivista, bem como facilitar a visualiza??o da rede de rela??es nos processos de ensino/aprendizagem

A smoking prevention program delivered by medical students to secondary schools in Brazil called ?Education Against Tobacco? : randomized controlled trial.

Background: Smoking is the largest preventable cause of mortality in Brazil. Education Against Tobacco (EAT) is a network of more than 3500 medical students and physicians across 14 countries who volunteer for school-based smoking prevention programs. EAT educates 50,000 adolescents per year in the classroom setting. A recent quasi-experimental study conducted in Germany showed that EAT had significant short-term smoking cessation effects among adolescents aged 11 to 15 years. Objective: The aim is to measure the long-term effectiveness of the most recent version of the EAT curriculum in Brazil. Methods: A randomized controlled trial was conducted among 2348 adolescents aged 12 to 21 years (grades 7-11) at public secondary schools in Brazil. The prospective experimental design included measurements at baseline and at 6 and 12 months postintervention. The study groups comprised randomized classes receiving the standardized EAT intervention (90 minutes of mentoring in a classroom setting) and control classes in the same schools (no intervention). Data were collected on smoking status, gender, social aspects, and predictors of smoking. The primary endpoint was the difference in the change in smoking prevalence between the intervention group and the control group at 12-month follow-up. Results: From baseline to 12 months, the smoking prevalence increased from 11.0% to 20.9% in the control group and from 14.1% to 15.6% in the intervention group. This difference was statistically significant (P<.01). The effects were smaller for females (control 12.4% to 18.8% vs intervention 13.1% to 14.6%) than for males (control 9.1% to 23.6% vs intervention 15.3% to 16.8%). Increased quitting rates and prevented onset were responsible for the intervention effects. The differences in change in smoking prevalence from baseline to 12 months between the intervention and control groups were increased in students with low school performance. Conclusions: To our knowledge, this is the first randomized trial on school-based tobacco prevention in Brazil that shows significant long-term favorable effects. The EAT program encourages quitting and prevents smoking onset, especially among males and students with low educational background

Tratamento para queloides : revis?o de literatura.

Introduction: Keloids are characterized by an abnormal response to dermal trauma, resulting in fibroblast proliferation, excessive collagen production, and impairment of adjacent healthy tissue. The diagnosis is clinical, and many conservative and surgical methods can be used as treatments. However, data on the efficacy of these treatments are limited, and there is no consensus regarding the best treatment option. This gap needs to be filled by developing comprehensive evidence-based therapies. Methods: A non-systematic literature review of keloid scars was carried out using PubMed, Scielo, MEDLINE, UptoDate, and dermatology and dermatological surgery textbooks. Literature review: The search retrieved relevant information on surgical and adjuvant therapies used for keloids, including excision, intralesional injections, cryotherapy, laser therapy, silicone gel sheeting, radiation therapy, and pressure therapy. These data are crucial because, in addition to complaints of pain, itching, and restriction of movement, the main reason for seeking treatment for keloids is for cosmetic and aesthetic improvement, and the rates of recurrence and treatment failure are high, emphasizing the importance of creating awareness regarding the available procedures and their effectiveness. Conclusion: Many surgical and adjuvant therapies for keloids are available. Nonetheless, there is no consensus on a universally accepted treatment. Therefore, additional high-quality studies are needed to identify the most effective therapeutic approaches to achieve better results