13,819 research outputs found
Modelagem Bayesiana em curvas de crescimento em bovinos de corte: Pantanal Sul-Mato-Grossense, sub - região de Aquidauana.
O ajuste de modelos de curvas de crescimento é utilizado para delinear o crescimento dos animais de um determinado grupo genético. O objetivo deste estudo foi ajustar curvas de alguns modelos não-lineares para determinar um padrão do crescimento de bezerros, machos e fêmeas, do grupo genético composto da raça Nelore do Pantanal Sul-Mato-Grossense, por meio de inferência Bayesiana. Foram ajustados os modelos Logístico e de Gompertz. Dentro do período analisado, os dois modelos foram adequados para descrever o crescimento dos animais. No entanto, os machos apresentaram peso assintótico superior ao das fêmeas
Comparação Bayesiana de modelos não-lineares para curvas de crescimento de bovinos Nelore criados no Pantanal Sul Mato Grossense, sub-região de Aquidauana.
O ajuste de modelos de curvas de crescimento é utilizado para delinear o crescimento dos animais de um determinado grupo genético. O objetivo deste estudo foi ajustar curvas de alguns modelos não-lineares para determinar um padrão do crescimento médio de bezerros do grupo genético composto da raça Nelore do Pantanal Sul-Mato-Grossense, por meio de inferência Bayesiana. Foram ajustados os modelos Logístico, de Brody, de Gompertz e Von Bertalanffy. Dentro do período analisado, os modelos Logístico e de Gompertz mostraram-se adequados para descrever o crescimento médio destes animais
Partial order and contextual net semantics for atomic and locally atomic CC programs
We present two concurrent semantics (i.e. semantics where concurrency is explicitely represented) for CC programs with atomic tells. One is based on simple partial orders of computation steps, while the other one is based on contextual nets and it is an extensión of a previous one for eventual CC programs. Both such semantics allow us to derive concurrency, dependency, and nondeterminism information for the considered languages. We prove some properties about the relation between the two semantics, and also about the relation between them and the operational semantics. Moreover, we discuss how to use the contextual net semantics in the context of CLP programs. More precisely, by interpreting concurrency as possible parallelism, our semantics can be useful for a safe parallelization of some CLP computation steps. Dually, the dependency information may also be interpreted as necessary
sequentialization, thus possibly exploiting it for the task of scheduling CC programs. Moreover, our semantics is also suitable for CC programs with a new kind of atomic tell (called locally atomic tell), which checks for consistency only the constraints it depends on. Such a tell achieves a reasonable trade-off between efficiency and atomicity, since the checked constraints can be stored in a local memory and are thus easily accessible even in a distributed implementation
Edge centrality via the Holevo quantity
In the study of complex networks, vertex centrality measures are used to identify the most important vertices within a graph. A related problem is that of measuring the centrality of an edge. In this paper, we propose a novel edge centrality index rooted in quantum information. More specifically, we measure the importance of an edge in terms of the contribution that it gives to the Von Neumann entropy of the graph. We show that this can be computed in terms of the Holevo quantity, a well known quantum information theoretical measure. While computing the Von Neumann entropy and hence the Holevo quantity requires computing the spectrum of the graph Laplacian, we show how to obtain a simplified measure through a quadratic approximation of the Shannon entropy. This in turns shows that the proposed centrality measure is strongly correlated with the negative degree centrality on the line graph. We evaluate our centrality measure through an extensive set of experiments on real-world as well as synthetic networks, and we compare it against commonly used alternative measures
Variational convergence of gradient flows and rate-independent evolutions in metric spaces
We study the asymptotic behaviour of families of gradient flows in a general
metric setting, when the metric-dissipation potentials degenerate in the limit
to a dissipation with linear growth. We present a general variational
definition of BV solutions to metric evolutions, showing the different
characterization of the solution in the absolutely continuous regime, on the
singular Cantor part, and along the jump transitions. By using tools of metric
analysis, BV functions and blow-up by time rescaling, we show that this
variational notion is stable with respect to a wide class of perturbations
involving energies, distances, and dissipation potentials. As a particular
application, we show that BV solutions to rate-independent problems arise
naturally as a limit of -gradient flows, , when the exponents
converge to 1
Modulational instability of solitary waves in non-degenerate three-wave mixing: The role of phase symmetries
We show how the analytical approach of Zakharov and Rubenchik [Sov. Phys.
JETP {\bf 38}, 494 (1974)] to modulational instability (MI) of solitary waves
in the nonlinear Schr\"oedinger equation (NLS) can be generalised for models
with two phase symmetries. MI of three-wave parametric spatial solitons due to
group velocity dispersion (GVD) is investigated as a typical example of such
models. We reveal a new branch of neck instability, which dominates the usual
snake type MI found for normal GVD. The resultant nonlinear evolution is
thereby qualitatively different from cases with only a single phase symmetry.Comment: 4 pages with figure
Pathological Angiogenesis Requires Syndecan-4 for Efficient VEGFA-Induced VE-Cadherin Internalization
Objective:
VEGFA (Vascular endothelial growth factor A) and its receptor VEGFR2 (vascular endothelial growth factor receptor 2) drive angiogenesis in several pathologies, including diabetic retinopathy, wet age-related macular degeneration, and cancer. Studies suggest roles for HSPGs (heparan sulfate proteoglycans) in this process, although the nature of this involvement remains elusive. Here, we set to establish the role of the HSPG SDC4 (syndecan-4) in pathological angiogenesis.
Approach and Results:
We report that angiogenesis is impaired in mice null for SDC4 in models of neovascular eye disease and tumor development. Our work demonstrates that SDC4 is the only SDC whose gene expression is upregulated during pathological angiogenesis and is selectively enriched on immature vessels in retinas from diabetic retinopathy patients. Combining in vivo and tissue culture models, we identified SDC4 as a downstream mediator of functional angiogenic responses to VEGFA. We found that SDC4 resides at endothelial cell junctions, interacts with vascular endothelial cadherin, and is required for its internalization in response to VEGFA. Finally, we show that pathological angiogenic responses are inhibited in a model of wet age-related macular degeneration by targeting SDC4.
Conclusions:
We show that SDC4 is a downstream mediator of VEGFA-induced vascular endothelial cadherin internalization during pathological angiogenesis and a potential target for antiangiogenic therapies
Pathological Angiogenesis Requires Syndecan-4 for Efficient VEGFA-Induced VE-Cadherin Internalization.
Objective: VEGFA (Vascular endothelial growth factor A) and its receptor VEGFR2 (vascular endothelial growth factor receptor 2) drive angiogenesis in several pathologies, including diabetic retinopathy, wet age-related macular degeneration, and cancer. Studies suggest roles for HSPGs (heparan sulfate proteoglycans) in this process, although the nature of this involvement remains elusive. Here, we set to establish the role of the HSPG SDC4 (syndecan-4) in pathological angiogenesis. / Approach and Results: We report that angiogenesis is impaired in mice null for SDC4 in models of neovascular eye disease and tumor development. Our work demonstrates that SDC4 is the only SDC whose gene expression is upregulated during pathological angiogenesis and is selectively enriched on immature vessels in retinas from diabetic retinopathy patients. Combining in vivo and tissue culture models, we identified SDC4 as a downstream mediator of functional angiogenic responses to VEGFA. We found that SDC4 resides at endothelial cell junctions, interacts with vascular endothelial cadherin, and is required for its internalization in response to VEGFA. Finally, we show that pathological angiogenic responses are inhibited in a model of wet age-related macular degeneration by targeting SDC4. / Conclusions:
We show that SDC4 is a downstream mediator of VEGFA-induced vascular endothelial cadherin internalization during pathological angiogenesis and a potential target for antiangiogenic therapies
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