762 research outputs found
Primary and secondary scintillation measurements in a xenon Gas Proportional Scintillation Counter
NEXT is a new experiment to search for neutrinoless double beta decay using a
100 kg radio-pure high-pressure gaseous xenon TPC. The detector requires
excellent energy resolution, which can be achieved in a Xe TPC with
electroluminescence readout. Hamamatsu R8520-06SEL photomultipliers are good
candidates for the scintillation readout. The performance of this
photomultiplier, used as VUV photosensor in a gas proportional scintillation
counter, was investigated. Initial results for the detection of primary and
secondary scintillation produced as a result of the interaction of 5.9 keV
X-rays in gaseous xenon, at room temperature and at pressures up to 3 bar, are
presented. An energy resolution of 8.0% was obtained for secondary
scintillation produced by 5.9 keV X-rays. No significant variation of the
primary scintillation was observed for different pressures (1, 2 and 3 bar) and
for electric fields up to 0.8 V cm-1 torr-1 in the drift region, demonstrating
negligible recombination luminescence. A primary scintillation yield of 81 \pm
7 photons was obtained for 5.9 keV X-rays, corresponding to a mean energy of 72
\pm 6 eV to produce a primary scintillation photon in xenon.Comment: 16 pages, 10 figures, accepted for publication in JINS
Surface rehabilitation of Portland cement concrete (PCC) pavements using single or double surface dressings with soft bitumen, conventional or modified emulsions
Surface dressings are a sustainable maintenance alternative for pavements with surface distresses, due to
the low amount of resources involved. This paper aims to analyze the viability of using twelve different
surface dressing solutions, including three binders (conventional and modified emulsions, and a soft
160/220 bitumen) and a covering with diluted emulsion, for surface treatment of Portland cement concrete
(PCC) pavements. Several test methods were used to evaluate the macrotexture, skid resistance,
adhesion, and resistance to wearing on a large scale prototype. In general, single surface dressings
increased further the macrotexture of the concrete pavement surface. The skid resistance of single and
double surface dressings was similar. The best surface dressing in the pull-off test was that with the
160/220 bitumen. The conventional and modified emulsions presented similar mechanical adhesion in
the Vialit plate test. Concerning the prototype wearing test, the best result was obtained for the double
surface dressing with bitumen covered with diluted emulsion. Based on this work’s results, the surface
dressings are a potential surface rehabilitation alternative for concrete pavements.This work was partially financed by FCT / MCTES through
national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020. This work is financed by national funds
through FCT - Foundation for Science and Technology, under grant
agreement SFRH/BD/137421/2018 attributed to the 1st author
Oilseeds native to the Cerrado have fatty acid profile beneficial for cardiovascular health
Infiltração da água no solo em resposta ao cultivo de longa duração em diferentes formas de manejo.
Produção de leite na pecuária familiar, em função do número de vacas ordenhas, períodos do ano e contagem de células somáticas.
Disponibilidade de fósforo em Latossolo do cerrado sob manejo convencional por mais de duas décadas.
O fósforo é um macronutriente essencial para as plantas, apresentando ligações de adsorção específica com os coloides do solo e, desta forma, ficando indisponível para a absorção pelas raízes. Assim, somente a adubação costuma não ser suficiente para oferecer a quantidade requerida pelas culturas, e grande parte do adicionado acaba não sendo aproveitado sendo mantido no solo em formas não lábeis. Neste contexto, este estudo tem como objetivo avaliar as frações disponíveis e lábeis de fósforo sob área de manejo convencional em experimento de longa duração. Amostras de solo de diferentes profundidades foram coletadas em áreas de cultivo de milho por mais de duas décadas, com preparo de solo convencional por arado de disco. Extrações sequenciais de P com resina trocadora de ânions (RTA) e NaHCO3 0,5 mol L-1 foram utilizadas como indicadoras das formas mais disponíveis. Os resultados indicaram que, mesmo após adubações anuais e por longo período, predominam baixos teores de formas mais disponíveis de P em solos sob cerrado
Bovine colostrum supplementation improves bone metabolism in an osteoporosis-induced animal model
Osteoporosis is characterized by bone loss. The present study aims to investigate the effects of bovine colostrum (BC) on bone metabolism using ovariectomized (OVX) and orchidectomized (ORX) rat models. Twenty-seven-week-old Wistar Han rats were randomly assigned as: (1) placebo control, (2) BC supplementation dose 1 (BC1: 0.5 g/day/OVX, 1 g/day/ORX), (3) BC supplementation dose 2 (BC2: 1 g/day/OVX, 1.5 g/day/ORX) and (4) BC supplementation dose 3 (BC3: 1.5 g/day/OVX, 2 g/day/ORX). Bone microarchitecture, strength, gene expression of VEGFA, FGF2, RANKL, RANK and OPG, and bone resorption/formation markers were assessed after four months of BC supplementation. Compared to the placebo, OVX rats in the BC1 group exhibited significantly higher cortical bone mineral content and trabecular bone mineral content (p < 0.01), while OVX rats in the BC3 group showed significantly higher trabecular bone mineral content (p < 0.05). ORX rats receiving BC dose 2 demonstrated significantly higher levels of trabecular bone mineral content (p < 0.05). Serum osteocalcin in the ORX was pointedly higher in all BC supplementation groups than the placebo (BC1: p < 0.05; BC2, BC3: p < 0.001). Higher doses of BC induced significantly higher relative mRNA expression of OPG, VEGFA, FGF2 and RANKL (p < 0.05). BC supplementation improves bone metabolism of OVX and ORX rats, which might be associated with the activation of the VEGFA, FGF2 and RANKL/RANK/OPG pathways.EC -European Commission(778277
Contagem de células somáticas influenciando a composição química do leite nos assentamentos rurais Palmares I e II.
Evaluation of headspace solid-phase microextraction gas chromatography - mass spectrometry for the characterization of volatile organic compounds from melon (Cucumis melo L.) flowers.
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