756 research outputs found
Low-background gamma spectroscopy at the Boulby Underground Laboratory
The Boulby Underground Germanium Suite (BUGS) comprises three low-background, high-purity germanium detectors operating in the Boulby Underground Laboratory, located 1.1 km underground in the north-east of England, UK. BUGS utilises three types of detector to facilitate a high-sensitivity, high-throughput radio-assay programme to support the development of rare-event search experiments. A Broad Energy Germanium (BEGe) detector delivers sensitivity to low-energy gamma-rays such as those emitted by 210 Pb and 234 Th. A Small Anode Germanium (SAGe) well-type detector is employed for efficient screening of small samples. Finally, a standard p-type coaxial detector provides fast screening of standard samples. This paper presents the steps used to characterise the performance of these detectors for a variety of sample geometries, including the corrections applied to account for cascade summing effects. For low-density materials, BUGS is able to radio-assay to specific activities down to 3.6mBqkg −1 for 234 Th and 6.6mBqkg −1 for 210 Pb both of which have uncovered some significant equilibrium breaks in the 238 U chain. In denser materials, where gamma-ray self-absorption increases, sensitivity is demonstrated to specific activities of 0.9mBqkg −1 for 226 Ra, 1.1mBqkg −1 for 228 Ra, 0.3mBqkg −1 for 224 Ra, and 8.6mBqkg −1 for 40 K with all upper limits at a 90% confidence level. These meet the requirements of most screening campaigns presently under way for rare-event search experiments, such as the LUX-ZEPLIN (LZ) dark matter experiment. We also highlight the ability of the BEGe detector to probe the X-ray fluorescence region which can be important to identify the presence of radioisotopes associated with neutron production; this is of particular relevance in experiments sensitive to nuclear recoils
Individual-environment interactions in swimming: The smallest unit for analysing the emergence of coordination dynamics in performance?
Displacement in competitive swimming is highly dependent on fluid characteristics,
since athletes use these properties to propel themselves. It is essential for sport
scientists and practitioners to clearly identify the interactions that emerge between
each individual swimmer and properties of an aquatic environment. Traditionally, the
two protagonists in these interactions have been studied separately. Determining the
impact of each swimmer’s movements on fluid flow, and vice versa, is a major
challenge. Classic biomechanical research approaches have focused on swimmers’
actions, decomposing stroke characteristics for analysis, without exploring
perturbations to fluid flows. Conversely, fluid mechanics research has sought to
record fluid behaviours, isolated from the constraints of competitive swimming
environments (e.g. analyses in two-dimensions, fluid flows passively studied on
mannequins or robot effectors). With improvements in technology, however, recent
investigations have focused on the emergent circular couplings between swimmers’
movements and fluid dynamics. Here, we provide insights into concepts and tools that
can explain these on-going dynamical interactions in competitive swimming within
the theoretical framework of ecological dynamics
Satisfação no trabalho da equipe de enfermagem: revisão integrativa
Job satisfaction consists of a feeling of wellbeing, resulting from the interaction of several occupational aspects, and may influence the worker's relationship with the organization, clients and family. Hence, it becomes important for the quality of nursing care to reflect on this topic in depth. Therefore, this study aimed to examine the scientific evidence related to job satisfaction in Brazilian nursing. An integrative literature review was carried out in the databases LILACS, MEDLINE, BDENF and Cochrane Library, totaling 17 publications, categorized in: Job Satisfaction, Job Dissatisfaction and Associated Factors. It was concluded that job satisfaction is determined by a complex network of factors and may vary depending on the group studied. Additional research, particularly of evidence level III in different nursing fields, covering all of Brazil, is necessary to support the implementation of occupational improvements.La satisfacción en el trabajo consiste en un sentimiento de bienestar resultante de la interacción de varios aspectos ocupacionales, pudiendo influenciar la relación del trabajador con la organización, clientes y familia. Es importante para la calidad de la asistencia de enfermería realizar una reflexión profunda sobre este tema, por eso se objetivó en este estudio analizar las evidencias científicas referentes a la satisfacción en el trabajo del equipo de enfermería brasileño. Se trató de una revisión integradora de la literatura en las bases de datos LILACS, MEDLINE, BDENF y Biblioteca Cochrane, totalizando 17 publicaciones categorizadas en: Satisfacción en el Trabajo, Insatisfacción en el Trabajo y Factores Asociados. Se concluyó que la satisfacción en el trabajo es determinada por una red compleja de factores, pudiendo variar conforme el grupo estudiado. Investigaciones adicionales, especialmente con niveles de evidencias III, en diferentes campos de actuación de la enfermería, abarcando todo el Brasil, son necesarias para subsidiar la implantación de mejorías ocupacionales.A satisfação no trabalho consiste em sentimento de bem-estar. resultante da interação de vários aspectos ocupacionais, podendo influenciar a relação do trabalhador com a organização, clientes e família. Torna-se importante, para a qualidade da assistência de enfermagem, reflexão aprofundada sobre esse tema, e, por isso, objetivou-se neste estudo analisar as evidências científicas referentes à satisfação no trabalho da equipe de enfermagem brasileira. Trata-se de revisão integrativa da literatura nas bases de dados LILACS, MEDLINE, BDENF e Biblioteca Cochrane, totalizando 17 publicações categorizadas em: satisfação no trabalho, insatisfação no trabalho e fatores associados. Conclui-se que a satisfação no trabalho é determinada por rede complexa de fatores, podendo variar conforme o grupo estudado. Pesquisas adicionais, especialmente com níveis de evidências III, em diferentes campos de atuação da enfermagem, abrangendo todo Brasil, são necessárias para subsidiar a implantação de melhorias ocupacionais
Transthoracic echocardiography reference values in juvenile and adult 129/Sv mice
Background In the recent years, the use of Doppler-echocardiography has become a standard non-invasive technique in the analysis of cardiac malformations in genetically modified mice. Therefore, normal values have to be established for the most commonly used inbred strains in whose genetic background those mutations are generated. Here we provide reference values for transthoracic echocardiography measurements in juvenile (3 weeks) and adult (8 weeks) 129/Sv mice.
Methods Echocardiographic measurements were performed using B-mode, M-mode and Doppler-mode in 15 juvenile (3 weeks) and 15 adult (8 weeks) mice, during isoflurane anesthesia. M-mode measurements variability of left ventricle (LV) was determined.
Results Several echocardiographic measurements significantly differ between juvenile and adult mice. Most of these measurements are related with cardiac dimensions. All B-mode measurements were different between juveniles and adults (higher in the adults), except for fractional area change (FAC). Ejection fraction (EF) and fractional shortening (FS), calculated from M-mode parameters, do not differ between juvenile and adult mice. Stroke volume (SV) and cardiac output (CO) were significantly different between juvenile and adult mice. SV was 31.93 ± 8.67 μl in juveniles vs 70.61 ± 24.66 μl in adults, ρ < 0.001. CO was 12.06 ± 4.05 ml/min in juveniles vs 29.71 ± 10.13 ml/min in adults, ρ < 0.001. No difference was found in mitral valve (MV) and tricuspid valve (TV) related parameters between juvenile and adult mice. It was demonstrated that variability of M-mode measurements of LV is minimal. Conclusions
This study suggests that differences in cardiac dimensions, as wells as in pulmonary and aorta outflow parameters, were found between juvenile and adult mice. However, mitral and tricuspid inflow parameters seem to be similar between 3 weeks and 8 weeks mice. The reference values established in this study would contribute as a basis to future studies in post-natal cardiovascular development and diagnosing cardiovascular disorders in genetically modified mouse mutant lines.Peer Reviewe
Qualidade de alface crespa cultivada em sistema orgânico, convencional e hidropônico.
O objetivo deste trabalho foi avaliar a qualidade da alface do grupo crespa, cv. Vera, em sistemas de cultivo orgânico, convencional e hidropônico em Rio Branco-AC. O experimento foi conduzido em julho de 2009. As amostras dos sistemas, convencional e hidropônico (3 marcas comerciais), foram escolhidas aleatoriamente nos supermercados do município de Rio Branco, no mesmo dia de coleta da alface produzida em sistema orgânico. A alface orgânica, produzida na área experimental do Setor de Agricultura Ecológica da Universidade Federal do Acre (UFAC), em Rio Branco, foi cultivada em estufa, sob plantio direto utilizando folhas de bambu como cobertura do solo, e adubada com composto orgânico (17 t ha-1 em base seca). O delineamento utilizado foi o inteiramente casualizado, com cinco tratamentos e quatro repetições compostas por três plantas. As amostras foram lavadas, cortadas e processadas com folha e caule, para obter o suco. Logo após foram determinados os teores de sólidos solúveis e a concentração de nitrato e ácido ascórbico. As três marcas de alface hidropônica apresentaram maior teor de nitrato e menor concentração de sólidos solúveis e ácidos ascórbico, enquanto a alface orgânica apresentou qualidade superior, com baixa concentração de nitrato e maior teor de ácido ascórbico
The Dynamics of Transmission and Spatial Distribution of Malaria in Riverside Areas of Porto Velho, Rondônia, in the Amazon Region of Brazil
The study area in Rondônia was the site of extensive malaria epidemic outbreaks in the 19th and 20th centuries related to environmental impacts, with large immigration flows. The present work analyzes the transmission dynamics of malaria in these areas to propose measures for avoiding epidemic outbreaks due to the construction of two Hydroelectric Power Plants. A population based baseline demographic census and a malaria prevalence follow up were performed in two river side localities in the suburbs of Porto Velho city and in its rural vicinity. The quantification and nature of malaria parasites in clinical patients and asymptomatic parasite carriers were performed using microscopic and Real Time PCR methodologies. Anopheles densities and their seasonal variation were done by monthly captures for defining HBR (hourly biting rate) values. Main results: (i) malaria among residents show the riverside profile, with population at risk represented by children and young adults; (ii) asymptomatic vivax and falciparum malaria parasite carriers correspond to around 15% of adults living in the area; (iii) vivax malaria relapses were responsible for 30% of clinical cases; (iv) malaria risk for the residents was evaluated as 20–25% for vivax and 5–7% for falciparum malaria; (v) anopheline densities shown outdoors HBR values 5 to 10 fold higher than indoors and reach 10.000 bites/person/year; (vi) very high incidence observed in one of the surveyed localities was explained by a micro epidemic outbreak affecting visitors and temporary residents. Temporary residents living in tents or shacks are accessible to outdoors transmission. Seasonal fishermen were the main group at risk in the study and were responsible for a 2.6 fold increase in the malaria incidence in the locality. This situation illustrates the danger of extensive epidemic outbreaks when thousands of workers and secondary immigrant population will arrive attracted by opportunities opened by the Hydroelectric Power Plants constructions
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