Optimizing single-photon-source heralding efficiency at 1550 nm using periodically poled lithium niobate

We explore the feasibility of using high conversion-efficiency periodically-poled crystals to produce photon pairs for photon-counting detector calibrations at 1550 nm. The goal is the development of an appropriate parametric down-conversion (PDC) source at telecom wavelengths meeting the requirements of high-efficiency pair production and collection in single spectral and spatial modes (single-mode fibers). We propose a protocol to optimize the photon collection, noise levels and the uncertainty evaluation. This study ties together the results of our efforts to model the single-mode heralding efficiency of a two-photon PDC source and to estimate the heralding uncertainty of such a source.Comment: 14 pages, 2 tables and 3 figures, final version accepted by Metrologi

Avalanche Photo-Detection for High Data Rate Applications

Avalanche photo detection is commonly used in applications which require single photon sensitivity. We examine the limits of using avalanche photo diodes (APD) for characterising photon statistics at high data rates. To identify the regime of linear APD operation we employ a ps-pulsed diode laser with variable repetition rates between 0.5MHz and 80MHz. We modify the mean optical power of the coherent pulses by applying different levels of well-calibrated attenuation. The linearity at high repetition rates is limited by the APD dead time and a non-linear response arises at higher photon-numbers due to multiphoton events. Assuming Poissonian input light statistics we ascertain the effective mean photon-number of the incident light with high accuracy. Time multiplexed detectors (TMD) allow to accomplish photon- number resolution by photon chopping. This detection setup extends the linear response function to higher photon-numbers and statistical methods may be used to compensate for non-linearity. We investigated this effect, compare it to the single APD case and show the validity of the convolution treatment in the TMD data analysis.Comment: 16 pages, 5 figure

Classificação do atendimento pré-hospitalar pediátrico como instrumento para otimizar a alocação de recursos no atendimento do trauma na cidade de São Paulo, Brasil

PURPOSE: To evaluate the pediatric prehospital care in São Paulo, the databases from basic life support units (BLSU) and ALSU, and to propose a simple and effective method for evaluating trauma severity in children at the prehospital phase. METHODS: A single firemen headquarter coordinates all prehospital trauma care in São Paulo city. Two databases were analyzed for children from 0 to 18 years old between 1998 and 2001: one from the Basic Life Support Units (BLSU - firemen) and one from the Advanced Life Support Units (ALSU - doctor and firemen). During this period, advanced life support units provided medical reports from 604 victims, while firemen provided 12.761 reports (BLSU+ALSU). Pre-Hospital Pediatric Trauma Classification is based on physiological status, trauma mechanism and anatomic injuries suggesting high energy transfer. In order to evaluate the proposed classification, it was compared to the Glasgow Coma Score and to the Revised Trauma Score. RESULTS: There was a male predominance in both databases and the most common trauma mechanism was transport related, followed by falls. Mortality was 1.6% in basic life support units and 9.6% in ALSU. There was association among the proposed score, the Glasgow Coma Score and to the Revised Trauma Score (p<0.0001). CONCLUSION: Pre-Hospital Pediatric Trauma Classification is a simple and reliable method for assessment, triage and recruitment of pediatric trauma resources.OBJETIVO: Avaliar o atendimento pré-hospitalar de crianças e adolescentes em São Paulo, avaliar o banco de dados das Unidades de Suporte Básico (UR) e Avançado (USA) e propor um método simples e eficaz para a avaliação da gravidade do trauma pediátrico na fase pré-hospitalar. MÉTODOS: Uma única central do Corpo de Bombeiros (COBOM) coordena todo o atendimento pré-hospitalar em São Paulo. Dois bancos de dados foram analisados para crianças de 0 a 18 anos de idade, entre 1998 e 2001: um das Unidades de Suporte Básico de Vida (UR- bombeiros) e outra de Unidades de Suporte Avançado (USA - médico e bombeiros). Neste período, o Serviço de Atendimento Médico de Urgência do Estado de São Paulo (SAMU) forneceu relatórios médicos de 604 vítimas, enquanto os bombeiros forneceram relatórios de 12.761 vitimas (UR+USA). A classificação do trauma pré-hospitalar pediátrico é baseada na condição fisiológica, mecanismo de trauma e lesões anatômicas das vítimas. A classificação do trauma pré-hospitalar pediátrico foi comparada à Escala de Coma de Glasgow (GCS) e ao Escore de Trauma Revisado (RTS). RESULTADOS: Houve predominância do sexo masculino em ambos bancos de dados. O mecanismo de trauma mais freqüente foi relacionado a transporte, seguido de quedas. A mortalidade foi 1,6% nas Unidades Básicas e 9,6% no Suporte Avançado. Houve associação entre a classificação do trauma pré-hospitalar pediátrico, Escala de Coma de Glasgow (GCS) e ao Escore de Trauma Revisado (RTS) GCS e RTS (p<0,0001). CONCLUSÃO: A classificação do trauma pré-hospitalar pediátrico é um método simples e confiável para a avaliação, triagem e recrutamento de recursos para o atendimento pré-hospitalar do trauma pediátrico.Universidade Federal de São Paulo (UNIFESP) Department of SurgeryUNIFESP, Department of SurgerySciEL

Uterine mesenchymal tumors: development and preliminary results of a magnetic resonance imaging (MRI) diagnostic algorithm

Purpose: The aim of our study is to propose a diagnostic algorithm to guide MRI findings interpretation and malignancy risk stratification of uterine mesenchymal masses with a multiparametric step-by-step approach. Methods: A non-interventional retrospective multicenter study was performed: Preoperative MRI of 54 uterine masses was retrospectively evaluated. Firstly, the performance of MRI with monoparametric and multiparametric approach was assessed. Reference standard for final diagnosis was surgical pathologic result (n = 53 patients) or at least 1-year MR imaging follow-up (n = 1 patient). Subsequently, a diagnostic algorithm was developed for MR interpretation, resulting in a Likert score from 1 to 5 predicting risk of malignancy of the uterine lesion. The accuracy and reproducibility of the MRI scoring system were then tested: 26 preoperative pelvic MRI were double-blind evaluated by a senior (SR) and junior radiologist (JR). Diagnostic performances and the agreement between the two readers with and without the application of the proposed algorithm were compared, using histological results as standard reference. Results: Multiparametric approach showed the best diagnostic performance in terms of accuracy (94.44%,) and specificity (97.56%). DWI was confirmed as the most sensible parameter with a relative high specificity: low ADC values (mean 0.66) significantly correlated to uterine sarcomas diagnosis (p &lt; 0.01). Proposed algorithm allowed to improve both JR and SR performance (algorithm-aided accuracy 88.46% and 96%, respectively) and determined a significant increase in inter-observer agreement, helping even the less-experienced radiologist in this difficult differential diagnosis. Conclusions: Uterine leiomyomas and sarcomas often show an overlap of clinical and imaging features. The application of a diagnostic algorithm can help radiologists to standardize their approach to a complex myometrial mass and to easily identify suspicious MRI features favoring malignancy

Medical treatment of prolactinomas.

Prolactinomas, the most prevalent type of neuroendocrine disease, account for approximately 40% of all pituitary adenomas. The most important clinical problems associated with prolactinomas are hypogonadism, infertility and hyposexuality. In patients with macroprolactinomas, mass effects, including visual field defects, headaches and neurological disturbances, can also occur. The objectives of therapy are normalization of prolactin levels, to restore eugonadism, and reduction of tumor mass, both of which can be achieved in the majority of patients by treatment with dopamine agonists. Given their association with minimal morbidity, these drugs currently represent the mainstay of treatment for prolactinomas. Novel data indicate that these agents can be successfully withdrawn in a subset of patients after normalization of prolactin levels and tumor disappearance, which suggests the possibility that medical therapy may not be required throughout life. Nevertheless, multimodal therapy that involves surgery, radiotherapy or both may be necessary in some cases, such as patients who are resistant to the effects of dopamine agonists or for those with atypical prolactinomas. This Review reports on efficacy and safety of pharmacotherapy in patients with prolactinomas

Propuesta de cadena de valor en la gesti?n integrada de residuos sector Oil y Gas

La industria de oil&gas se encuentra en una etapa importante con exigencias hacia un desarrollo sustentable y sostenible en orden a las nuevas tendencias del mundo, para la implementaci?n de propuestas innovadoras en relaci?n a su entorno y el impacto generado en su cadena productiva. Investigar la cadena de valor representa oportunidades para el an?lisis y presentaci?n de casos de estudio que promueven a la investigaci?n en temas de relevancia a sus estrategias de negocio y ciclos productivos. La investigaci?n aplicada analiza la problem?tica de la log?stica inversa y la relaci?n con la gesti?n de residuos, plan de abandono y de comisionado. Utilizando el an?lisis cualitativo y cuantitativo de la informaci?n recolectada de diversas fuentes, se responde a la hip?tesis del estudio, desarrollando una soluci?n basada en estrategias por ?reas de impacto como el planeamiento, operaciones, finanzas, medio ambiente y responsabilidad social; realizando un an?lisis de evaluaci?n econ?mica que permite visualizar resultados en indicadores como el VAN y TIR, la sensibilidad de las variables como el precio, cantidad de producci?n y costos operativos, que afectan las proyecciones en el escenario actual como el an?lisis econ?mico, logrando demostrar beneficios tangibles y no tangibles que pueden ser implementados como propuesta de valor

Single-cell analyses of Crohn’s disease tissues reveal intestinal intraepithelial T cells heterogeneity and altered subset distributions

Crohn’s disease (CD) is a chronic transmural inflammation of intestinal segments caused by dysregulated interaction between microbiome and gut immune system. Here, we profile, via multiple single-cell technologies, T cells purified from the intestinal epithelium and lamina propria (LP) from terminal ileum resections of adult severe CD cases. We find that intraepithelial lymphocytes (IEL) contain several unique T cell subsets, including NKp30+γδT cells expressing RORγt and producing IL-26 upon NKp30 engagement. Further analyses comparing tissues from non-inflamed and inflamed regions of patients with CD versus healthy controls show increased activated TH17 but decreased CD8+T, γδT, TFH and Treg cells in inflamed tissues. Similar analyses of LP find increased CD8+, as well as reduced CD4+T cells with an elevated TH17 over Treg/TFH ratio. Our analyses of CD tissues thus suggest a potential link, pending additional validations, between transmural inflammation, reduced IEL γδT cells and altered spatial distribution of IEL and LP T cell subsets

Intra-tidal variation of stratification in a semi-arid estuary under the impact of flow regulation

The Jaguaribe River is the largest semi-arid Brazilian river and represents an important water source for the state of Ceará. The Castanhão Weir, built to regulate the flow of the Jaguaribe, began operating successfully in the 1990s. As a result, the hydrodynamic regime of the estuary has undergone alteration and is no longer subject to the former annual climatological variability of the dry and rainy seasons. This paper introduces an assessment of the changes in the hydrological conditions resulting from the construction of the weir and investigates the structure of the density stratification in the estuary. A field experiment was conducted at the end of the dry season in November 2009, during which salinity and temperature were monitored at different levels for three tidal cycles. The temporal variations in salinity and temperature during the tidal cycles were 16 psu and 1.5°C, respectively. The salinity exhibited a vertical variation of four units, while the temperature variation was much lower. Several stratification indicators were calculated from the observed density: the stratification coefficient, the Brunt-Väisälä frequency and the potential energy anomaly. The results showed that the parameters behave similarly, differences being observed only in their relative magnitudes. The vertical structure of the estuary exhibited marked stratification during the ebb tide but vertical homogeneity during both flood and high tide. With the regularized flow existing under present conditions, the estuary exhibits hyposaline and a partially mixed structure for the period studied, despite the typical expectation of a hypersaline and well-mixed vertical structure.O rio Jaguaribe é o maior rio do semi-árido brasileiro, constituindo uma importante fonte de água para o estado do Ceará. Na década de 1990 entrou em operação o Açude do Castanhão com o objetivo de regularizar a vazão do rio Jaguaribe, o qual obteve grande sucesso. Como consequência foi alterado o regime hidrodinâmico do estuário, o qual atualmente não está mais sujeito a variabilidade climatológica anual de estações seca e chuvosa. O presente trabalho apresenta uma avaliação da mudança do regime hidrológico antes e após a construção do açude, e investiga a estrutura de estratificação da densidade nos estuários. Foi realizado um experimento de campo em novembro de 2009, no fim da estação seca, quando a salinidade e temperatura da água foram monitorados em diferentes níveis durante três ciclos de maré. A variação temporal da salinidade e temperatura durante os ciclos de maré foram de 16 psu e 1,5ºC, respectivamente. A salinidade chegou a apresentar variação vertical de 4 unidades, enquanto que a variação da temperatura foi bem inferior. Foram calculados parâmetros indicadores da estratificação a partir da densidade: coeficiente de estratificação; frequência de Brunt-Väisälä; e a anomalia da energia potencial. Os resultados mostraram que os parâmetros comportam-se da mesma maneira, apenas com diferença da magnitude relativa de seus valores. A estrutura vertical do estuário apresentou estratificação pronunciada durante a fase de vazante da maré, e verticalmente homogênea na fase de enchente da maré e durante a preamar. Dada as condições presentes, com vazão regularizada, o estuário apresenta padrão de estratificação parcialmente misturado e hiposalino, quando seria esperado uma condição bem misturada e hipersalina para o período estudado