363 research outputs found
Two new species of Cyperus (Cyperaceae) from Brazil
Abstract Two new species of Cyperus L. (Cyperaceae), both from Brazil, are described and compared to near relatives. Cyperus hooperae is described from two collections from the Chapada do Veadeiros in the State of Goiás; it is most similar to C. refractus of the southeastern U.S. Cyperus thomasii is described from a single collection from the municipality of Caruaru in Pernambuco; it is most similar to C. granatensis of Colombia. Following IUCN standards, both are considered threatened
Incorporating oldman saltbush hay and prickly pear in diets for red Sindhi calves
This study was designed to evaluate the nutrient intake, digestibility, degradability, and ruminal characteristics of Sindhi heifers fed diets that contained a combined total of 75% oldman saltbush hay (hereafter saltbush hay) and prickly pear cactus. Eight 12-month old intact male red Sindhi calves (four fistulated and four non-fistulated) with an initial mean weight of 170 ± 5 kg were assigned to 4 × 4 Latin squares, where factors consisted of four diets, namely 15% hay and 60% cactus; 30% hay and 45% cactus; 45% hay and 30% cactus; and 60% hay and 15% cactus, and four times at which rumen fluid was collected. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) intakes in kg/day and NDF in percentage live weight (LW), water intake, salinity, and conductivity increased with hay level. Intake and digestibility of non-fibrous carbohydrates were curvilinear with higher values in diets containing 30% saltbush hay. The apparent digestibility of dry matter (DM) and organic matter decreased linearly as the concentration of saltbush hay increased in the diet. The pH of the rumen fluid was within the acceptable range for favourable microbial growth. The low temperature and high salinity and conductivity indices in the diets should be viewed with caution at higher concentrations of saltbush hay, because of a possible decrease in nutrient absorption and the development of health problems in the animals. Apparent degradability coefficients of DM and NDF were affected significantly by inclusion of prickly pear and saltbush hay in the diets.Keywords: animal nutrition, apparent digestibility, Atriplex nummularia Lindl, Opuntia ficus, ruminal degradation, semi-arid environmen
Density Perturbations in the Brans-Dicke Theory
We analyse the fate of density perturbation in the Brans-Dicke Theory, giving
a general classification of the solutions of the perturbed equations when the
scale factor of the background evolves as a power law. We study with details
the cases of vacuum, inflation, radiation and incoherent matter. We find, for
the a negative Brans-Dicke parameter, a significant amplification of
perturbations.Comment: 26 pages, latex fil
Estimation of the OSNR penalty due to in-band crosstalk on the performance of virtual carrier-assisted metropolitan OFDM systems
The impact of the in-band crosstalk on the performance of virtual carrier (VC)-assisted direct detection (DD) multi-band orthogonal frequency division multiplexing (MB-OFDM) systems was numerically assessed via Monte-Carlo simulations, by means of a single interferer and 4-ary, 16-ary and 64-ary quadrature amplitude modulation (QAM) formats in the OFDM subcarriers. It was also investigated the influences of the virtual carrier-to-band power ratio (VBPR) and the virtual carrier-to-band gap (VBG) on the DD in-band crosstalk tolerance of the OFDM receiver. It was shown the modulation format order decrease enhances the tolerance to in-band crosstalk. When the VBG is the same for both interferer and selected signal, the interferer VBPR increase is seen to lead to lower optical signal-to-noise ratio (OSNR) penalties due to in-band crosstalk. Considering that the VCs frequencies of the selected and interferer OFDM signals are equal, the increase of the interferer VBG also gives rise to lower OSNR penalties. When the interferer and selected signals bands central frequencies are the same, the change of interferer VBG can attain 11 dB less tolerance to in-band crosstalk of the VC-assisted DD OFDM system. We also evaluate the error vector magnitude (EVM) accuracy of the in-band crosstalk tolerance of the DD OFDM receiver and our results show that the EVM estimations are inaccurate.info:eu-repo/semantics/acceptedVersio
Hotspots of soil pollution: possible glyphosate and aminomethylphosphonic acid risks on terrestrial ecosystems and human health
The study presents a literature review of glyphosate (GLY) occurrence and its breakdown product, aminomethylphosphonic acid (AMPA), in soils worldwide, but with a specific focus on South America. In addition, an ecological risk approach based on the ecotoxicological endpoints for key soil biota (e.g., collembolans, and earthworms) assessed the impact of GLY and AMPA on these organisms. A generic probabilistic model for human health risk was also calculated for the different world regions. For what reports the risk for edaphic species and the level of pollution under the worst-case scenario, the South American continent was identified as the region of most concern. Nonetheless, other areas may also be in danger, but no risk could be calculated due to the lack of data. Since tropical countries are the top food exporters worldwide, the results obtained in this study must be carefully examined for their implications on a global scale. Some of the factors behind the high levels of these two chemicals in soils are debated (e.g., permissive protection policies, the extensive use of genetically modified crops), and some possible guidelines are presented that include, for example, further environmental characterisation and management of pesticide residues. The present review integrates data that can be used as a base by policymakers and decision-makers to develop and implement environmental policies
Inhalation of the prodrug PI3K inhibitor CL27c improves lung function in asthma and fibrosis
PI3K activation plays a central role in the development of pulmonary inflammation and tissue remodeling. PI3K inhibitors may thus offer an improved therapeutic opportunity to treat non-resolving lung inflammation but their action is limited by unwanted on-target systemic toxicity. Here we present CL27c, a prodrug pan-PI3K inhibitor designed for local therapy, and investigate whether inhaled CL27c is effective in asthma and pulmonary fibrosis. Mice inhaling CL27c show reduced insulin-evoked Akt phosphorylation in lungs, but no change in other tissues and no increase in blood glycaemia, in line with a local action. In murine models of acute or glucocorticoid-resistant neutrophilic asthma, inhaled CL27c reduces inflammation and improves lung function. Finally, inhaled CL27c administered in a therapeutic setting protects from bleomycin-induced lung fibrosis, ultimately leading to significantly improved survival. Therefore, local delivery of a pan-PI3K inhibitor prodrug reduces systemic on-target side effects but effectively treats asthma and irreversible pulmonary fibrosis
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