6,396 research outputs found
Substituição da torta de algodão por feno de leguminosas em rações baseadas em restolho da cultura do milho para ovinos em confinamento.
Resumo: Dois experimentos usando ovinos deslanados testaram a substituiçao da torta de algodao por feno de Ieguminosas em rações corn restolho da cultura do milho. No primeiro experimento, foi usada uma raçao-base de 51% restolho do milho, 28% torta de algodao, 20% milho e 1% sal, na quaI a torta de algodao foi substituîda por 5%, 10%, e 15% de feno de mata-pasto (Cassia sericea), enquanto um Iote-testemunha era mantido em pastoreio. Os animais confinados ganharam 95, 106, 103 e 93 gramas/cabeça/dia (P > 0,05), para as rações com 0%, 5%, 10% e 15% de mata-pasto, respectivamente. Os animais em pastoreio perderam 11 gramas/cabeça/dia (P 0.05) for tho rations with 0%, 5%, 10% and 15% of "mata-pasto", respective-ly. The grazing animais iost 11 grams/head/day , (P <0.05). in the second experiment, the cottonseed calce was either partiaiiy (50%) or totaily repiacod by "mata-pasto" or "cunha" (ditaria terl7atee) hays, whiie the grazing sheep received a suppiementation of 200 grams of corn grain/headldayWith the exception of the treatment In which the eottonseed cake was totaily repiaced by "mata-pasto" hay, the other treatments with coniined animais showed gains above 100 grams/head/day, which were hi -,er than (P <0.01) the 42 grams/head/day for the grazing animais. The resuits indicate that it is possibie to substituto "mata-pasto" hay for cottonseed calce ar leveis up to 50%, while the total substitution Lan be made "cunhâ" Is used
The Dynamical Instability of Static, Spherically Symmetric Solutions in Nonsymmetric Gravitational Theories
We consider the dynamical stability of a class of static,
spherically-symmetric solutions of the nonsymmetric gravitational theory. We
numerically reproduce the Wyman solution and generate new solutions for the
case where the theory has a nontrivial fundamental length scale \mu^{-1}. By
considering spherically symmetric perturbations of these solutions we show that
the Wyman solutions are generically unstable.Comment: 13 pages, uses amslatex, graphicx and subfigure package
Static charged perfect fluid spheres in general relativity
Interior perfect fluid solutions for the Reissner-Nordstrom metric are
studied on the basis of a new classification scheme. General formulas are found
in many cases. Explicit new global solutions are given as illustrations. Known
solutions are briefly reviewed.Comment: 23 pages, Revtex (galley), journal version, to appear in Phys.Rev.
A probabilistic model of the economic risk to Britain’s railway network from bridge scour during floods
Scour (localized erosion by water) is an important risk to bridges, and hence many infrastructure networks, around the world. In Britain, scour has caused the failure of railway bridges crossing rivers in more than 50 flood events. These events have been investigated in detail, providing a data set with which we develop and test a model to quantify scour risk. The risk analysis is formulated in terms of a generic, transferrable infrastructure network risk model. For some bridge failures, the severity of the causative flood was recorded or can be reconstructed. These data are combined with the background failure rate, and records of bridges that have not failed, to construct fragility curves that quantify the failure probability conditional on the severity of a flood event. The fragility curves generated are to some extent sensitive to the way in which these data are incorporated into the statistical analysis. The new fragility analysis is tested using flood events simulated from a spatial joint probability model for extreme river flows for all river gauging sites in Britain. The combined models appear robust in comparison with historical observations of the expected number of bridge failures in a flood event. The analysis is used to estimate the probability of single or multiple bridge failures in Britain's rail network. Combined with a model for passenger journey disruption in the event of bridge failure, we calculate a system-wide estimate for the risk of scour failures in terms of passenger journey disruptions and associated economic costs
Substitution of legume hays for cottonseed cake in rations based on corn crop residues for sheep under confinement
Dois experimentos usando ovinos deslanados testaram a substituição da torta de algodão por feno de leguminosas em rações com restolho da cultura do milho. No primeiro experimento, foi usada uma ração-base de 51% restolho do milho, 28% torta de algodão, 20% milho e 1% sal, na qual a torta de algodão foi substituída por 5%, 10%, e 15% de feno de mata-pasto (Cassia sericea), enquanto um lote-testemunha era mantido em pastoreio. Os animais confinados ganharam 95, 106, 103 e 93 gramas/cabeça/dia (P>0,05), para as rações com 0%, 5%, 10% e 15% de mata-pasto, respectivamente. Os animais em pastoreio perderam 11 gramas/cabeça/dia (P0.05) for the rations with 0%, 5%, 10% and 15% of "mata-pasto", respectively. The grazing animals lost 11 grams/head/day, (P<0.05). In the second experiment, the cottonseed cake was either partially (50%) or totally replaced by "mata-pasto" or "cunhã" (Clitoria ternatea) hays, while the grazing sheep received a supplementation of 200 grams of corn grain/head/day. With the exception of the treatment in which the cottonseed cake was totally replaced by "mata-pasto" hay, the other treatments with confined animals showed gains above 100 grams/head/day, which were higher than (P<0.01) the 42 grams/head/day for the grazing animals. The results indicate that it is possible to substitute "mata-pasto" hay for cottonseed cake at levels up to 50%, while the total substitution can be made "cunhã" is used
MAGE-A cancer/testis antigens inhibit MDM2 ubiquitylation function and promote increased levels of MDM4
Melanoma antigen A (MAGE-A) proteins comprise a structurally and biochemically similar sub-family of Cancer/Testis antigens that are expressed in many cancer types and are thought to contribute actively to malignancy. MAGE-A proteins are established regulators of certain cancer-associated transcription factors, including p53, and are activators of several RING finger-dependent ubiquitin E3 ligases. Here, we show that MAGE-A2 associates with MDM2, a ubiquitin E3 ligase that mediates ubiquitylation of more than 20 substrates including mainly p53, MDM2 itself, and MDM4, a potent p53 inhibitor and MDM2 partner that is structurally related to MDM2. We find that MAGE-A2 interacts with MDM2 via the N-terminal p53-binding pocket and the RING finger domain of MDM2 that is required for homo/hetero-dimerization and for E2 ligase interaction. Consistent with these data, we show that MAGE-A2 is a potent inhibitor of the E3 ubiquitin ligase activity of MDM2, yet it does not have any significant effect on p53 turnover mediated by MDM2. Strikingly, however, increased MAGE-A2 expression leads to reduced ubiquitylation and increased levels of MDM4. Similarly, silencing of endogenous MAGE-A expression diminishes MDM4 levels in a manner that can be rescued by the proteasomal inhibitor, bortezomid, and permits increased MDM2/MDM4 association. These data suggest that MAGE-A proteins can: (i) uncouple the ubiquitin ligase and degradation functions of MDM2; (ii) act as potent inhibitors of E3 ligase function; and (iii) regulate the turnover of MDM4. We also find an association between the presence of MAGE-A and increased MDM4 levels in primary breast cancer, suggesting that MAGE-A-dependent control of MDM4 levels has relevance to cancer clinically
Population policies and education: exploring the contradictions of neo-liberal globalisation
The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation contains inherent contradictions regarding choice and uniformity. This is illustrated in this paper through an exploration of the impact of neo-liberal globalisation on population policies and programmes. The dominant neo-liberal economic ideology that has influenced development over the last few decades has often led to alternative global visions being overlooked. Many current population and development debates are characterised by polarised arguments with strongly opposing aims and views. This raises the challenge of finding alternatives situated in more middle ground that both identify and promote the socially positive elements of neo-liberalism and state intervention, but also to limit their worst excesses within the population field and more broadly. This paper concludes with a discussion outling the positive nature of middle ground and other possible alternatives
Structural analysis of MDM2 RING separates degradation from regulation of p53 transcription activity
MDM2–MDMX complexes bind the p53 tumor-suppressor protein, inhibiting p53's transcriptional activity and targeting p53 for proteasomal degradation. Inhibitors that disrupt binding between p53 and MDM2 efficiently activate a p53 response, but their use in the treatment of cancers that retain wild-type p53 may be limited by on-target toxicities due to p53 activation in normal tissue. Guided by a novel crystal structure of the MDM2–MDMX–E2(UbcH5B)–ubiquitin complex, we designed MDM2 mutants that prevent E2–ubiquitin binding without altering the RING-domain structure. These mutants lack MDM2's E3 activity but retain the ability to limit p53′s transcriptional activity and allow cell proliferation. Cells expressing these mutants respond more quickly to cellular stress than cells expressing wild-type MDM2, but basal p53 control is maintained. Targeting the MDM2 E3-ligase activity could therefore widen the therapeutic window of p53 activation in tumors
Photoproduction of meson pairs: First measurement of the polarization observable I^s
The polarization observable I^s, a feature exclusive to the acoplanar
kinematics of multi-meson final states produced via linearly polarized photons,
has been measured for the first time. Results for the reaction g p -> p pi0 eta
are presented for incoming photon energies between 970 MeV and 1650 MeV along
with the beam asymmetry I^c. The comparably large asymmetries demonstrate a
high sensitivity of I^s to the dynamics of the reaction. Fits using
Bonn-Gatchina partial wave analysis demonstrate that the new polarization
observables carry significant information on the contributing partial waves.Comment: 11 pages, 6 figures, v2 to appear in Phys. Lett.
Parallel Excluded Volume Tempering for Polymer Melts
We have developed a technique to accelerate the acquisition of effectively
uncorrelated configurations for off-lattice models of dense polymer melts which
makes use of both parallel tempering and large scale Monte Carlo moves. The
method is based upon simulating a set of systems in parallel, each of which has
a slightly different repulsive core potential, such that a thermodynamic path
from full excluded volume to an ideal gas of random walks is generated. While
each system is run with standard stochastic dynamics, resulting in an NVT
ensemble, we implement the parallel tempering through stochastic swaps between
the configurations of adjacent potentials, and the large scale Monte Carlo
moves through attempted pivot and translation moves which reach a realistic
acceptance probability as the limit of the ideal gas of random walks is
approached. Compared to pure stochastic dynamics, this results in an increased
efficiency even for a system of chains as short as monomers, however
at this chain length the large scale Monte Carlo moves were ineffective. For
even longer chains the speedup becomes substantial, as observed from
preliminary data for
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