7,672 research outputs found

    Radon Exhalation from Industrial Residues as Suitable Additives for Building Materials

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    Radon exhalation from phosphogypsum (PG) and red mud (RM) samples are of environmental concern. The study is oriented to evaluate by different nuclear techniques, industrial materials cumulated in sites at Morón (PG) and Puerto Ordaz (RM) in Venezuela. RM samples and industrial by products are assessed for its potential use as additives in building materials regarding its radiological health risk. Radioactive matter concentration in RM is up to 11.6 kBq.kg-1. Radon concentration range for RM dry powder is between DL and 2.5 kBq.m-³ and for PG is between 105-340 Bq.m-³. Results indicate that industrial by product before it can be used as additive; require remedial actions to lower the environmental impact. Experimental values are compared with locally available cement, bricks and gypsum building materials

    Prevalence and management of cardiovascular risk factors in Portuguese living in Portugal and Portuguese who migrated to Switzerland.

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    BACKGROUND: Information regarding the health status of migrants compared to subjects who remain in the country of origin is scarce. We compared the levels and management of the main cardiovascular risk factors between Portuguese living in Porto (Portugal) and Portuguese migrants living in Lausanne (Switzerland). METHODS: Cross-sectional studies conducted in Porto (EPIPorto, 1999 to 2003, n = 1150) and Lausanne (CoLaus, 2003 to 2006, n = 388) among subjects aged 35-65 years. Educational level, medical history and time since migration were collected using structured questionnaires. Body mass index, blood pressure, cholesterol and glucose levels were measured using standardized procedures. RESULTS: Portuguese living in Lausanne were younger, more frequently male and had lower education than Portuguese living in Porto. After multivariate adjustment using Poisson regression, no differences were found between Portuguese living in Porto or in Lausanne: prevalence rate ratio (PRR) and (95% confidence interval) for Portuguese living in Lausanne relative to Portuguese living in Porto: 0.92 (0.71 - 1.18) for current smoking; 0.78 (0.59 - 1.04) for obesity; 0.81 (0.62 - 1.05) for abdominal obesity; 0.82 (0.64 - 1.06) for hypertension; 0.88 (0.75 - 1.04) for hypercholesterolemia and 0.92 (0.49 - 1.73) for diabetes. Treatment and control rates for hypercholesterolemia were higher among Portuguese living in Lausanne: PRR = 1.91 (1.15 - 3.19) and 3.98 (1.59 - 9.99) for treatment and control, respectively. Conversely, no differences were found regarding hypertension treatment and control rates: PRR = 0.98 (0.66 - 1.46) and 0.97 (0.49 - 1.91), respectively, and for treatment rates of diabetes: PRR = 1.51 (0.70 - 3.25). CONCLUSIONS: Portuguese living in Lausanne, Switzerland, present a similar cardiovascular risk profile but tend to be better managed regarding hypercholesterolemia than Portuguese living in Porto, Portugal

    Efeito das temperaturas e substratos sobre a germinação de Parkia gigantocarpa Ducke (Leguminosae-Mimosoideae).

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    Parkia gigantocarpa Ducke, conhecida popularmente como Fava- Atanã é uma espécie de grande porte, que pode ser utilizada para produção de celulose, recomposição de áreas degradadas e construção em geral. O objetivo desse estudo foi verificar a influência de diferentes substratos e temperaturas sobre a germinação de sementes de P. gigantocarpa. Realizou-se um experimento inteiramente casualizado em esquema fatorial 5 x 5, com 4 repetições de 25 sementes, por um período de 12 dias. Foram utilizados diferentes substratos (rolo de papel, areia, areia + serragem (1:1), vermiculita e fibra de coco triturada) em função de diferentes temperaturas constantes (15, 20, 25, 30 e 35ºC). Nas temperaturas de 15 e 20ºC houve inibição no desenvolvimento normal das plântulas, ocorrendo germinação de plântulas normais somente nas temperaturas de 25, 30 e 35°C. No geral, a temperatura de 30°C foi a mais favorável para a germinação das sementes de P. gigantocarpa, tendo como melhores substratos a areia, areia + serragem (1:1) e fibra de coco

    Detection of vanA-containing Enterococcus species in faecal microbiota of gilthead seabream (Sparus aurata)

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    Vancomycin-resistant Enterococcus faecalis, E. faecium and E. durans isolates with the genotype vanA were detected in 7 of 118 faecal samples (5.9%) of natural gilthead seabream recovered off the coast of Portugal, and one vancomycinresistant isolate/sample was further characterized. The genes erm(B), tet(L), tet(M), aac(6')-aph(2"), aph(3')-IIIa and/ or ant(6)-Ia were identified in most of the 7 vancomycin-resistant enterococci. Sequence types ST273, ST313 and ST76 were detected in three E. faecium isolates and ST6 in two E. faecalis isolates. VanA-containing enterococci are suggested to be disseminated in fish in marine ecosystems close to areas of human activity

    Exact Energy-Time Uncertainty Relation for Arrival Time by Absorption

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    We prove an uncertainty relation for energy and arrival time, where the arrival of a particle at a detector is modeled by an absorbing term added to the Hamiltonian. In this well-known scheme the probability for the particle's arrival at the counter is identified with the loss of normalization for an initial wave packet. Under the sole assumption that the absorbing term vanishes on the initial wave function, we show that ΔTΔEp/2\Delta T \Delta E \geq \sqrt p \hbar/2 and ΔE1.37p \Delta E\geq 1.37\sqrt p\hbar, where ee denotes the mean arrival time, and pp is the probability for the particle to be eventually absorbed. Nearly minimal uncertainty can be achieved in a two-level system, and we propose a trapped ion experiment to realize this situation.Comment: 8 pages, 2 figure

    SDSS J124058.03-015919.2: A new AM CVn star with a 37-minute orbital period

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    We present high time resolution VLT spectroscopy of SDSS J124058.03-015919.2, a new helium-transferring binary star identified in the Sloan Digital Sky Survey. We measure an orbital period of 37.355+/-0.002 minutes, confirming the AM CVn nature of the system. From the velocity amplitudes of the accretor and the accretion stream--disc impact, we derive a mass ratio q=0.039+/-0.010. Our spectral coverage extends from 3700A--9500A and shows the presence of helium, nitrogen, silicon and iron in the accretion disc, plus the redshifted, low-velocity "central spikes" in the helium lines, known from the low-state AM CVn stars GP Com and CE 315. Doppler tomography of the helium and silicon emission lines reveals an unusual pattern of two bright emission sites in the tomograms, instead of the usual one emission site identified with the impact of the mass stream into the accretion disc. One of the two is preferred as the conventional stream--disc impact point in velocity space, at the 3-sigma confidence level. We speculate briefly on the origin of the second.Comment: Accepted for publication in MNRA

    An extreme [OIII] emitter at z=3.2z=3.2: a low metallicity Lyman continuum source

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    [Abridged] We investigate the physical properties of a Lyman continuum emitter candidate at z=3.212z=3.212 with photometric coverage from UU to MIPS 24μ\mum band and VIMOS/VLT and MOSFIRE/Keck spectroscopy. Investigation of the UV spectrum confirms a direct spectroscopic detection of the Lyman continuum emission with S/N>5S/N>5. Non-zero Lyα\alpha flux at the systemic redshift and high Lyman-α\alpha escape fraction suggest a low HI column density. The weak C and Si low-ionization absorption lines are also consistent with a low covering fraction along the line of sight. The [OIII]λλ4959,5007+Hβ\lambda\lambda4959,5007+\mathrm{H}\beta equivalent width is one of the largest reported for a galaxy at z>3z>3 (EW([OIII]λλ4959,5007+Hβ)1600A˚\mathrm{EW}([\mathrm{OIII}]\lambda\lambda4959,5007+\mathrm{H}\beta) \simeq 1600\AA, rest-frame) and the NIR spectrum shows that this is mainly due to an extremely strong [OIII] emission. The large observed [OIII]/[OII] ratio (>10>10) and high ionization parameter are consistent with prediction from photoionization models in case of a density-bounded nebula scenario. Furthermore, the EW([OIII]λλ4959,5007+Hβ)\mathrm{EW}([\mathrm{OIII}]\lambda\lambda4959,5007+\mathrm{H}\beta) is comparable to recent measurements reported at z79z\sim7-9, in the reionization epoch. We also investigate the possibility of an AGN contribution to explain the ionizing emission but most of the AGN identification diagnostics suggest that stellar emission dominates instead. This source is currently the first high-zz example of a Lyman continuum emitter exhibiting indirect and direct evidences of a Lyman continuum leakage and having physical properties consistent with theoretical expectation from Lyman continuum emission from a density-bounded nebula.Comment: 14 pages, 11 figures, accepted for publication in A&A. Minor modifications, Figure 2 updated, Figure 9 adde
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