Data Analysis of the Water and Scintillator Phases of SNO+ : from Solar Neutrino Measurements to Double Beta Decay Sensitivity Studies

SNO+ is a leading liquid scintillator experiment for neutrino physics, with the ultimate goal of conducting a low background search for 0ѵꞵꞵ decay using 1300 kg of 130Te. The observation of this lepton-number-violating nuclear transition would provide fundamental insights regarding the neutrino mass and nature, opening doors to physics beyond the Standard Model. The success of this search relies on a complete understanding of the backgrounds contaminating the 0ѵꞵꞵ region-of-interest, and an accurate model of the energy response of the detector. Both are addressed continuously during three different stages of the experiment’s operations – water, scintillator and Te-loaded phases. This thesis presents the analysis of data taken during the water and scintillator phases of the SNO+ experiment. Optical calibration data taken with a deployed source during the water phase allowed to measure for the first time in situ key optical parameters for the detector model, which will be common to all phases. The initial liquid scintillator data, taken during a 7 month transition period when the detector was half-filled with 365 tonnes of liquid scintillator on top of water, was used to characterize the intrinsic background contaminants in the scintillator. The background model was validated with a target-out double beta decay analysis, which tested for any unexpected background sources or leakage within the expected 0ѵꞵꞵ decay region-of-interest. Moreover, these data allowed the first physics measurement using scintillator in SNO+ – a measurement of the 8B solar neutrino flux, Փ8B =6.534 (+26.11%)/(-22.39%) (stat.) (+11.38%)/(-9.64%) (syst.) X 106 cm-2 s-1 with an exposure of 11.2 kt day, compatible with previous measurements by other experiments. Based on the best knowledge of the backgrounds in the detector and of its energy response, a Monte Carlo based analysis was performed in order to evaluate the expected precision for the measurement of the 2ѵββ decay of 130Te, one of the major intrinsic background expected for the 0ѵββ search. Due to the large detector mass and isotope loading, SNO+ will achieve exposures competitive with other double beta decay experiments and statistical uncertainties well below 1% with a few months of data. It is expected that the future half-life measurement will be limited by systematic uncertainties due to energy scale and background correlations, which could be on the order of 5%. These will have to be accurately determined and minimized using calibrations after the tellurium is loaded

Bayesian nonparametric inference for the three-class Youden index and its associated optimal cut-points

The three-class Youden index serves both as a measure of medical test accuracy and a criterion to choose the optimal pair of cutoff values for classifying subjects into three ordinal disease categories (e.g. no disease, mild disease, advanced disease). We present a Bayesian nonparametric approach for estimating the three-class Youden index and its corresponding optimal cutoff values based on Dirichlet process mixtures, which are robust models that can handle intricate features of distributions for complex data. Results from a simulation study are presented and an application to data from the Trail Making Test to assess cognitive impairment in Parkinson’s disease patients is detailed. </jats:p

A cada formando, uma estratégia de formação? A experiência dos serviços de formação da Biblioteca do Iscte na inclusão de estudantes guineenses

Na sequência de uma proposta de ação de formação sobre boas práticas na elaboração de trabalhos científicos, a Biblioteca do Iscte integrou uma parceria, gerida pelo Laboratório de Competências Transversais, para aplicar conteúdos de formação nessa mesma temática a estudantes estrangeiros. Percebeu, contudo, que os destinatários tinham especificidades que mereciam o desenvolvimento de um trabalho dirigido, dado tratar-se de um conjunto de estudantes oriundos da Guiné-Bissau, a frequentar o 2.º ciclo, com dificuldades de compreensão da língua portuguesa e herdeiros de um sistema de ensino desestruturado devido à Guerra. De forma a dar a melhor resposta às suas necessidades práticas na elaboração de trabalhos académicos, foi definido um plano de formação constituído por três módulos com o objetivo de responder às questões Como começar?, Como fazer? e Como apresentar? A formação foi dada em formato de oficina, ministrada por duas formadoras, tendo sido contruídos materiais de apoio que incluíram fichas de sistematização de conteúdos e exercícios práticos feitos em contexto de sala, com acompanhamento. A apresentação deste trabalho pretende expor as estratégias utilizadas como resultado da preocupação existente na inclusão destes estudantes e, sobretudo, refletir sobre as lições aprendidas, desmistificando, em simultâneo, alguns preconceitos.publicad

Optimization of raw ewes’ milk high-pressure pre-treatment for improved production of raw milk cheese

Serra da Estrela protected designation of origin (PDO) cheese is manufactured with raw milk from Bordaleira and/or Churra Mondegueira da Serra da Estrela sheep breeds. Several socio-environmental shortcomings have reduced production capacity; hence, treatments that may contribute to its efficient transformation into cheese are welcome. High-pressure processing (HPP) milk pre-treatment may contribute to a cheese yield increment, yet optimization of processing conditions is warranted. An initial wide-scope screening experiment allowed for pinpointing pressure intensity, holding time under pressure and time after HPP as the most important factors influencing curd yield. Based on this, a more targeted screening experiment allowed for selecting the range of experimental conditions to be used for an experimental design study that revealed an HPP treatment at 121 MPa for 30 min as the optimum for milk processing to improve curd yield (>9%) and effectively maintain the beneficial cheese microbiota; the optimum was validated in a final experimental framework

In situ assessment of the normal incidence sound absorption coefficient of asphalt mixtures with a new impedance tube

Normal incidence sound absorption coefficient of materials is usually calculated with the use of an impedance tube following the ISO 10534-2 international standard. The same is applied in the evaluation of the sound absorption characteristics of pavement mixtures. In this research an impedance tube which was specifically designed to be used in field conditions has been developed. In order test the tube six asphalt slabs were constructed in laboratory and its sound absorption coefficient measured with the new impedance tube. Then, several road sections, with different types of surface, among dense asphalt layers and thin layers, namely with rubberized asphalt were tested. In this paper, some considerations are made regarding the performance of the new impedance tube and the sound absorption coefficient of each asphalt mixtures.(undefined

Sound absorption coefficient of wet gap graded asphalt mixtures

Acoustic absorption properties of materials have often been used to reduce the generation and propagation of sound. The research carried out in this paper deals with sound absorption in relation to road surface layers. As the presence of water affects significantly the noise generated by the tyre-road contact, an evaluation of the sound absorption coefficient was made to several wet gap-graded mixtures with different levels of porosity and different contents of rubberized asphalt bitumen. A vacuum device was used to soak the interstices of the cores with water, which were then tested by means of an impedance tube, according with standard ISO 10534-2:1998. It was found that the values of the normal incidence sound absorption coefficient became smeared over the frequency spectrum in comparison with dry samples and that the quantity of rubber in the asphalt bitumen affected the way water fills the cores and, consequently, its sound absorption characteristics.(undefined

DOE: high-pressure processing as a pre-treatment for production of raw ewe milk-cheese

info:eu-repo/semantics/publishedVersio

First report of Thielaviopsis paradoxa causing stem rot in Dracaena marginata in Brazil.

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