433 research outputs found
Effect of Winter Grazing Management of Stockpiled Native Pastures of Basaltic Soils of Uruguay on Daily Gains of Heifers
The effect of three grazing systems of fall stockpiled native pastures on the winter gains of 66 Hereford heifers (135 kg) was studied. Treatments were: continuos grazing (CG); (C7) the plot was divided in 12 and each was grazed for 7 days and (C28), the plot was divided in 3 and each were grazed for 28 days. Heifers were weighed every 14 days and grazing behaviour was recorded. Stockpiled HM was greater (P\u3c 0.05) in C7 and C28 than in CG (988, 912, and 604 kg DM/ha, respectively). Herbage allowance (HA) was greater (P\u3c 0.01) in CG followed by C28 and C7 (11.7, 6.6 and 5.9 kg DM/100 kg LW, respectively). Post-grazing HM was greater (P0.05) in all pastures (CP 10.2%, NDF 71.2%, ADF 41.3% and ash 14.4%). Final LW of heifers were similar (P\u3e 0.05) (167, 162 and 160 kg for CG, C7 and C28, respectively). A very mild winter favoured exceptional gains which tended to be higher in CG (0.353 kg/day) than in C7 (0.305 kg/day) and C28 (0.278 kg/day). Grazing time was greater (P\u3c 0.05) in CG and bite rate was lower in C28 than in C7 and CG heifers. Grazing management did not affect daily gains. Nevertheless, total remaining HM in C28 and more so in C7 more than doubled that in CG, where more animals could have grazed with increasing total productivity
Mixed Fattening of Steers and Lambs on Improved Grasslands in Uruguay: II. Animal Performance and Productivity
In cow-calf operations in Uruguay, mixed cattle and sheep grazing on rangelands is predominant, while fattening is a specialised process. Within certain limits of the lamb/steer ratio and stocking rate, a complementary grazing effect occurs under mixed grazing, improving net results (Nolan & Connolly, 1977; Risso et al., 2002). These trials characterise animal performance under such management
Mixed Fattening of Steers and Lambs on Improved Grasslands in Uruguay: I. Pasture Performance
The use of P fertilisers together with legume broadcasting is a low cost and high impact technology for improving native grassland (Risso et al., 2001). Its use is increasing in Uruguay, although not for mixed grazing, even though this management is a common practice on native grasslands. Good pasture response may occur under mixed grazing when it is adequately managed (Nolan & Connolly, 1989). The following trials characterise pasture response with such management, in Uruguayan conditions
QAPgrid: A Two Level QAP-Based Approach for Large-Scale Data Analysis and Visualization
Background: The visualization of large volumes of data is a computationally challenging task that often promises rewarding new insights. There is great potential in the application of new algorithms and models from combinatorial optimisation. Datasets often contain “hidden regularities” and a combined identification and visualization method should reveal these structures and present them in a way that helps analysis. While several methodologies exist, including those that use non-linear optimization algorithms, severe limitations exist even when working with only a few hundred objects. Methodology/Principal Findings: We present a new data visualization approach (QAPgrid) that reveals patterns of similarities and differences in large datasets of objects for which a similarity measure can be computed. Objects are assigned to positions on an underlying square grid in a two-dimensional space. We use the Quadratic Assignment Problem (QAP) as a mathematical model to provide an objective function for assignment of objects to positions on the grid. We employ a Memetic Algorithm (a powerful metaheuristic) to tackle the large instances of this NP-hard combinatorial optimization problem, and we show its performance on the visualization of real data sets. Conclusions/Significance: Overall, the results show that QAPgrid algorithm is able to produce a layout that represents the relationships between objects in the data set. Furthermore, it also represents the relationships between clusters that are feed into the algorithm. We apply the QAPgrid on the 84 Indo-European languages instance, producing a near-optimal layout. Next, we produce a layout of 470 world universities with an observed high degree of correlation with the score used by the Academic Ranking of World Universities compiled in the The Shanghai Jiao Tong University Academic Ranking of World Universities without the need of an ad hoc weighting of attributes. Finally, our Gene Ontology-based study on Saccharomyces cerevisiae fully demonstrates the scalability and precision of our method as a novel alternative tool for functional genomics
Hygroscopic Water Retention and Physio-Chemical Properties of Three In-House Produced Biochars from Different Feedstock Types: Implications on Substrate Amendment in Green Infrastructure
Recent studies have proposed usage of biochar as a substrate amendment in green infrastructure, such as green roofs and bio-filtration units. However, understanding of the variation in physio-chemical properties of biochar due to the production process and feedstock is still lacking. The present study investigated the effects of pyrolysis temperature and feedstocks on the hygroscopic water content and physio-chemical properties of biochar. Biochars were produced from three feedstock types, invasive vegetation (i.e., water hyacinth), non-invasive vegetation (i.e., wood) and one animal waste (i.e., chicken manure). Biochar was produced at two different pyrolysis temperatures (i.e., 300 °C and 600 °C). Scanning electron microscopy + energy dispersive spectrometry (SEM + EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) were performed on all samples to analyze the surface morphology, pore size, element content, functional groups, and chemical bonds. Relative humidity was adjusted to reflect the biochar’s hygroscopic property by measuring the maximum moisture content at the sample equilibrium state. The characterization reveals that the lowest carbon content (42.78%) was found at 300 °C for water hyacinth biochar (WHB). The highest carbon content (92.14%) was found at 600 °C for wood biochar (WB). As the pyrolysis temperature increased, the mean pore volume (from 0.03 to 0.18 cm3/g) and diameter (from 8.40 to 10.33 nm) of the WHB increased. However, the pore diameter of chicken manure (CB) decreased (from 9.23 nm to 7.53 nm) under an increase in pyrolysis temperature. For a given pyrolysis temperature, the hygroscopicity of WHB was highest among all biochars. With an increase in pyrolysis temperature, the hygroscopicity of biochars changed differently. The hygroscopicity of WHB decreased from 82.41% to 44.33% with an increase of pyrolysis temperature. However, the hygroscopicity of CMB and WB remained unchanged. This study suggests that production process of biochars need to be considered for appropriate selection as substrate material in green infrastructure. Further, it promotes the establishment of commercial production of biochar for usage in green infrastructure
Hyperphosphorylation of the cardiac ryanodine receptor at serine 2808 is not involved in cardiac dysfunction after myocardial infarction.
RATIONALE: Abnormal behavior of the cardiac ryanodine receptor (RyR2) has been linked to cardiac arrhythmias and heart failure (HF) after myocardial infarction (MI). It has been proposed that protein kinase A (PKA) hyperphosphorylation of the RyR2 at a single residue, Ser-2808, is a critical mediator of RyR dysfunction, depressed cardiac performance, and HF after MI.
OBJECTIVE: We used a mouse model (RyRS2808A) in which PKA hyperphosphorylation of the RyR2 at Ser-2808 is prevented to determine whether loss of PKA phosphorylation at this site averts post MI cardiac pump dysfunction.
METHODS AND RESULTS: MI was induced in wild-type (WT) and S2808A mice. Myocyte and cardiac function were compared in WT and S2808A animals before and after MI. The effects of the PKA activator Isoproterenol (Iso) on L-type Ca(2+) current (I(CaL)), contractions, and [Ca(2+)](I) transients were also measured. Both WT and S2808A mice had depressed pump function after MI, and there were no differences between groups. MI size was also identical in both groups. L type Ca(2+) current, contractions, Ca(2+) transients, and SR Ca(2+) load were also not significantly different in WT versus S2808A myocytes either before or after MI. Iso effects on Ca(2+) current, contraction, Ca(2+) transients, and SR Ca(2+) load were identical in WT and S2808A myocytes before and after MI at both low and high concentrations.
CONCLUSIONS: These results strongly support the idea that PKA phosphorylation of RyR-S2808 is irrelevant to the development of cardiac dysfunction after MI, at least in the mice used in this study
Absence of neuronal autoantibodies in neuropsychiatric systemic lupus erythematosus
International audienceThis study aimed to characterise both neuronal autoantibodies and levels of interferon α, two proposed causative agents in neuropsychiatric systemic lupus erythematosus (NPSLE). Cerebrospinal fluid (CSF) and plasma from 35 patients with systemic lupus erythematosus (SLE; 15 with NPSLE) showed no antibodies against natively expressed N-methyl-D-aspartate receptors (NMDARs), or the surface of live hippocampal neurons. By comparison to controls (n = 104), patients with SLE had antibodies that bound to a peptide representing the extracellular domain of NMDARs (p < 0.0001), however, binding was retained against both rearranged peptides and no peptide (r = 0.85 and r = 0.79, respectively, p < 0.0001). In summary, neuronal-surface reactive antibodies were not detected in NPSLE. Further, while interferon α levels were higher in SLE (p < 0.0001), they lacked specificity for NPSLE. Our findings mandate a search for novel biomarkers in this condition. ANN NEUROL 2020
Fermi and Swift Observations of GRB 190114C: Tracing the Evolution of High-energy Emission from Prompt to Afterglow
We report on the observations of gamma-ray burst (GRB) 190114C by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory. The prompt gamma-ray emission was detected by the Fermi GRB Monitor (GBM), the Fermi Large Area Telescope (LAT), and the Swift Burst Alert Telescope (BAT) and the long-lived afterglow emission was subsequently observed by the GBM, LAT, Swift X-ray Telescope (XRT), and Swift UV Optical Telescope. The early-time observations reveal multiple emission components that evolve independently, with a delayed power-law component that exhibits significant spectral attenuation above 40 MeV in the first few seconds of the burst. This power-law component transitions to a harder spectrum that is consistent with the afterglow emission observed by the XRT at later times. This afterglow component is clearly identifiable in the GBM and BAT light curves as a slowly fading emission component on which the rest of the prompt emission is superimposed. As a result, we are able to observe the transition from internal-shock- to external-shock-dominated emission. We find that the temporal and spectral evolution of the broadband afterglow emission can be well modeled as synchrotron emission from a forward shock propagating into a wind-like circumstellar environment. We estimate the initial bulk Lorentz factor using the observed high-energy spectral cutoff. Considering the onset of the afterglow component, we constrain the deceleration radius at which this forward shock begins to radiate in order to estimate the maximum synchrotron energy as a function of time. We find that even in the LAT energy range, there exist high-energy photons that are in tension with the theoretical maximum energy that can be achieved through synchrotron emission from a shock. These violations of the maximum synchrotron energy are further compounded by the detection of very high-energy (VHE) emission above 300 GeV by MAGIC concurrent with our observations. We conclude that the observations of VHE photons from GRB 190114C necessitates either an additional emission mechanism at very high energies that is hidden in the synchrotron component in the LAT energy range, an acceleration mechanism that imparts energy to the particles at a rate that is faster than the electron synchrotron energy-loss rate, or revisions of the fundamental assumptions used in estimating the maximum photon energy attainable through the synchrotron process
Independent Validation of the SWMM Green Roof Module
Green roofs are a popular Sustainable Drainage Systems (SuDS) technology. They provide multiple benefits, amongst which the retention of rainfall and detention of runoff are of particular interest to stormwater engineers. The hydrological performance of green roofs has been represented in various models, including the Storm Water Management Model (SWMM). The latest version of SWMM includes a new LID green roof module, which makes it possible to model the hydrological performance of a green roof by directly defining the physical parameters of a green roof’s three layers. However, to date, no study has validated the capability of this module for representing the hydrological performance of an extensive green roof in response to actual rainfall events. In this study, data from a previously-monitored extensive green roof test bed has been utilised to validate the SWMM green roof module for both long-term (173 events over a year) and short-term (per-event) simulations. With only 0.357% difference between measured and modelled annual retention, the uncalibrated model provided good estimates of total annual retention, but the modelled runoff depths deviated significantly from the measured data at certain times (particularly during summer) in the year. Retention results improved (with the difference between modelled and measured annual retention decreasing to 0.169% and the Nash-Sutcliffe Model Efficiency (NSME) coefficient for per-event rainfall depth reaching 0.948) when reductions in actual evapotranspiration due to reduced substrate moisture availability during prolonged dry conditions were used to provide revised estimates of monthly ET. However, this aspect of the model’s performance is ultimately limited by the failure to account for the influence of substrate moisture on actual ET rates. With significant differences existing between measured and simulated runoff and NSME coefficients of below 0.5, the uncalibrated model failed to provide reasonable predictions of the green roof’s detention performance, although this was significantly improved through calibration. To precisely model the hydrological behaviour of an extensive green roof with a plastic board drainage layer, some of the modelling structures in SWMM green roof module require further refinement
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