745 research outputs found
Measuring The Co2 Flux At The Air/water Interface In Lakes Using Flow Injection Analysis.
The carbon dioxide flux at the air/water interface in lakes was calculated after the determination of H2CO3* (free CO2) and atmospheric CO2 using flow injection analysis (FIA) coupled to a conductometric detector. The method is based on the diffusion of CO2 through a hydrophobic membrane into a flow of deionized water, generating a gradient of conductivity proportional to the concentration of CO2 in the sample. Using one experimental set-up, the speciation of the inorganic carbon (H2CO3* and dissolved inorganic carbon) was accomplished by simply adjusting the sample pH. The determination of CO2 in the atmosphere was carried out by direct injection of the gaseous samples. The FIA apparatus was taken into the field and CO2 fluxes were evaluated in several Brazilian lakes. In these lakes, representing different eutrophic stages, the CO2 flux varied from -242 (invasive) up to 3227 (evasive) mumol CO2 m-2 h-1.3317-2
Caffeine as an indicator of estrogenic activity in source water
Caffeine has already been used as an indicator of anthropogenic impacts, especially the ones related to the disposal of sewage in water bodies. In this work, the presence of caffeine has been correlated with the estrogenic activity of water samples measured using the BLYES assay. After testing 96 surface water samples, it was concluded that caffeine can be used to prioritize samples to be tested for estrogenic activity in water quality programs evaluating emerging contaminants with endocrine disruptor activity.Caffeine has already been used as an indicator of anthropogenic impacts, especially the ones related to the disposal of sewage in water bodies. In this work, the presence of caffeine has been correlated with the estrogenic activity of water samples measur16818661869FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2008/57808-1 ; 2012/00303-0573894/2008-6This is a contribution of the INCTAA (FAPESP, proc. 2008/57808-1 and CNPq proc. 573894/2008-6). C.C.M. is grateful to FAPESP for the PhD fellowship (proc. 2012/00303-0)
Two-dimensional Magnetic Correlations And Partial Long-range Order In Geometrically Frustrated Sr2yruo6.
Neutron diffraction on the double perovskite Sr(2)YRuO(6) with a quasi-fcc lattice of Ru moments reveals planar magnetic correlations that condense into a partial long-range ordered state with coupled alternate antiferromagnetic (AFM) YRuO(4) square layers coexisting with the short-range correlations below T(N1) = 32 K. A second transition to a fully ordered AFM state below T(N2) = 24 K is observed. The reduced dimensionality of the spin correlations is arguably due to a cancellation of the magnetic coupling between consecutive AFM square layers in fcc antiferromagnets, which is the simplest three-dimensional frustrated magnet model system.11001720
Simulação hidrológica-hidrodinâmica e análise da possível influência do vento na extraordinária inundação de 1941 em Porto Alegre
The great flood of 1941 remains the most impactful and traumatic flood event in the history of Porto Alegre. This event was caused by a combination of heavy rainfall in the basin in the days prior to the peak of the flood, and the wind that occurred during the flood. However, the influence of wind on the maximum flood level, although frequently mentioned, is not well known. This is largely because there are no systematic data for wind speed measuring and direction in 1941. Therefore, the present work aims to estimate the discharge and the maximum flood level in the city of Porto Alegre and in other relevant points of the basin. using hydrologicalhydrodynamic modeling and, from there, analyze the possible role of the wind during the flood, through the simulation of hypothetical wind scenarios. The results showed that the discharges and levels were represented reasonably well with the MGB model at several locations in the basin. In relation to the 1941 event and the scenarios created, the contribution of the wind to the peak of the flood was of the order of a few to tens of centimeters, showing its potential role despite the limitations of the model.A grande cheia de 1941 continua a ser o evento de inundação mais impactante e traumático da história de Porto Alegre. Esse evento foi causado por uma combinação da grande precipitação na bacia nos dias anteriores ao pico da cheia, e do vento ocorrido durante a cheia. Entretanto, a influência do vento sobre o nível máximo da cheia, embora frequentemente mencionado, não é bem conhecida. Isto ocorre em grande parte porque não existem dados sistemáticos de medição de velocidade e direção do vento em 1941. Portanto, o presente trabalho tem como objetivo estimar a vazão e a cota máxima da cheia na cidade de Porto Alegre e em outros pontos relevantes da bacia utilizando a modelagem hidrológica-hidrodinâmica e, a partir daí, analisar o possível papel do vento durante a cheia, através da simulação de cenários hipotéticos de vento. Os resultados mostraram que as vazões e níveis foram representados razoavelmente bem com o modelo MGB em diversos locais da bacia. Em relação ao evento de 1941 e os cenários montados, a contribuição do vento para o pico da cheia foi da ordem de poucos a dezenas de centímetros, evidenciando o potencial papel do mesmo apesar das limitações do modelo
Observações sobre papilomatose em bovinos
The A. A., in this paper, relate the observations on a bovine herd affected by papilloma or common warts; it was treated with the specific medicament "Figueirina", made in the "Laboratório de Biologia Veterinária", of Matias Barbosa, Minas Gerais, Brazil. In twenty-six affected animals, twenty showed complete cure after the treatment, three of them improved, and the other three didn't show any satisfactory results. Among the cured animals, twelve were young and eight were adult. The uncured animals were all adult. In most cases, the warts disappeared rapidly with two applications. In those animals that had resisted four applications, the warts didn't disappear, even with greater dosis. "Figueirina" showed more efficience in the treatment of young animals
D-branes, surface operators, and ADHM quiver representations
A supersymmetric quantum mechanical model is constructed for BPS states bound to surface operators in five dimensional SU(r) gauge the- ories using D-brane engineering. This model represents the effective action of a certain D2-brane configuration, and is naturally obtained by dimensional reduction of a quiver (0,2) gauged linear sigma model. In a special stability chamber, the resulting moduli space of quiver representations is shown to be smooth and isomorphic to a moduli space of framed quotients on the projec- tive plane. A precise conjecture relating a K-theoretic partition function of this moduli space to refined open string invariants of toric lagrangian branes is formulated for conifold and local P1
7 P1 geometries
Heterotic Compactification, An Algorithmic Approach
We approach string phenomenology from the perspective of computational
algebraic geometry, by providing new and efficient techniques for proving
stability and calculating particle spectra in heterotic compactifications. This
is done in the context of complete intersection Calabi-Yau manifolds in a
single projective space where we classify positive monad bundles. Using a
combination of analytic methods and computer algebra we prove stability for all
such bundles and compute the complete particle spectrum, including gauge
singlets. In particular, we find that the number of anti-generations vanishes
for all our bundles and that the spectrum is manifestly moduli-dependent.Comment: 36 pages, Late
A influência da alimentação verde na postura
A test was conducted at Poultry Department of "Luiz de Queiroz" School of Agriculture to prove the effect of green feed on egg production. One hundred Rhode Island Red hens at plain laying period were divided in ten pens. The lot A was constituted of pens 1 to 5 and the lot B of pens 6 to 10. During 16 days the pens 1 to 5 did not receive green feed and the pens 6 to 10 received it with abundance. After and for a period of 30 days the situation was inverted. The analysis were made considering, a) the production of all chickens and b) discarding the chickens with irregular laying. In both cases the results were statistically insignificant, proving that green feed did not improve egg production
Nota sôbre um possível fator sub-letal em gado Holstein-Friesian
In this note the A. A. relate the occurrence of a possible sub-lethal factor, on the Holstein-Friesian herd of Escola Superior de Agricultura "Luiz de Queiroz", Piracicaba. The sire Horto was mated with his own mother, Brisa, and so, were obtained two calves, a male and a female, consecutively. Both the calves presented flexion and deviation of the fore legs. The sire's death has not alloved further observations. The study of these history cases excludes the mother's nutritional deficiency, as the cause of related phenomenon. In the consulted literature, VEIGA and MEAD et al. relate similar cases, although these are observed in other breeds of cattle The A. A. admit that cause of occurrence is a possible sublethal recessive factor, put in evidence by inbreeding
Population decline in the critically endangered Musschia isambertoi (Campanulaceae) endemic to Desertas Islands (Madeira Archipelago) calls for urgent conservation management
Macaronesian islands display a high degree of plant endemicity and correspond to some of the most threatened
biodiversity hotspots due to several human driven impacts such as habitat loss, invasive species, overexploitation
or climate change. The conservation status of the largest of the two known population of Musschia isambertoi M.
Seq., R. Jardim, Magda Silva and L. Carvalho (Campanulaceae) was assessed recently. Field work was done in
June 2018 in “Porto das Moças” Deserta Grande (Madeira Archipelago, Portugal), the locus typicus, where in
2006 close to 30 plants were detected with a high variation of age/size between individuals comprising both fully
flowering and non-flowering adult plants as well as seedlings, and thus corresponding to a healthy population.
This study assesses population size, age and plant size, and genetic, as well as floristic diversity. The total area of
the site corresponds to approximately 1500 square meters. Ten individuals were detected, all corresponding to
young seedlings not exceeding 15 cm high, and exhibiting approximately the same size and numbers of leaves
(4–8). No adult plants or remains of adult plants were seen. Ecological data and direct herbivory evidence suggest
that perennial plants are subjected to elimination during the short summer by the feral goat population. Mo lecular data based on ISSR markers show that the nine sampled individuals (out of ten individuals found) are
genetically identical, possibly resulting from one parental plant. Results clearly suggest that Musschia isambertoi
is very close to extinction. Urgent conservation measures are imperative and should include the immediate
fencing of the population followed by the elimination of feral goats from Deserta Grande. The elimination of feral
goats was initiated in 1996 (LIFE95 NAT/P/000125, 383,467.00 €) but stopped due to inappropriate conser vation policies of the former Services of the Natural Park of Madeira.info:eu-repo/semantics/publishedVersio
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