9,922 research outputs found
Experimentation with Accumulation
We study signal-dependent experimentation in the presence of accumulation and show that the passive-learner’s action surprisingly coincides with the experimentor’s when the unknown term is the one determining the decay rate of the stock, while they differ when the parameter being learned is the one measuring the accumulation rate. These results highlight the importance of the dynamic structure of the problem in signal-dependent experimentation. Moreover, they have important consequences for the pollutionaccumulation debate currently in progress.
Creating Urban Agriculture in the Corridors of Freedom - Case of the Turffontein Node
Planning Honours Final Report 2014, Wits UniversityThe concept of urban agriculture as a phenomenon is fast gaining momentum throughout the world. Although there has been great recognition of the social benefits associated with urban agricultural initiatives, such as poverty reduction, increasing food security and creating employment opportunities, this research focuses on the spatial design and planning of urban food gardens and how urban agriculture is manifesting in the City of Johannesburg. This research sought to establish how urban agriculture manifests in the City of Johannesburg with a focus on the Corridors of Freedom plans, which are being put forward by the City of Johannesburg, of which special attention has been given to the Turffontein Node in this report. Despite the spatial and physical orientation of the paper, the effects of aspects such as safety, security, education and management of space has been touched on and assists in the understanding of the nature of various spaces available for urban food gardens. Viewing urban agriculture as an ‘in-fill’ activity means that it is not seen as something that the city is responsible for implementing but instead is something that anyone can begin if they are able to identify the correct spaces available.CompAir S
Entropy production, viscosity bounds and bumpy black holes
The ratio of shear viscosity to entropy density, η/s, is computed in various holographic geometries that break translation invariance (but are isotropic). The shear viscosity does not have a hydrodynamic interpretation in such backgrounds, but does quantify the rate of entropy production due to a strain. Fluctuations of the metric components δg xy are massive about these backgrounds, leading to η/s < 1/(4π) at all finite temperatures (even in Einstein gravity). As the temperature is taken to zero, different behaviors are possible. If translation symmetry breaking is irrelevant in the far IR, then η/s tends to a constant at T = 0. This constant can be parametrically small. If the translation symmetry is broken in the far IR (which nonetheless develops emergent scale invariance), then η/s ∼ T 2 ν as T → 0, with ν ≤ 1 in all cases we have considered. While these results violate simple bounds on η/s, we note that they are consistent with a possible bound on the rate of entropy production due to strain
Thermal conductivity at a disordered quantum critical point
© 2016, The Author(s). Abstract: Strongly disordered and strongly interacting quantum critical points are difficult to access with conventional field theoretic methods. They are, however, both experimentally important and theoretically interesting. In particular, they are expected to realize universal incoherent transport. Such disordered quantum critical theories have recently been constructed holographically by deforming a CFT by marginally relevant disorder. In this paper we find additional disordered fixed points via relevant disordered deformations of a holographic CFT. Using recently developed methods in holographic transport, we characterize the thermal conductivity in both sets of theories in 1+1 dimensions. The thermal conductivity is found to tend to a constant at low temperatures in one class of fixed points, and to scale as T0.3 in the other. Furthermore, in all cases the thermal conductivity exhibits discrete scale invariance, with logarithmic in temperature oscillations superimposed on the low temperature scaling behavior. At no point do we use the replica trick
Emergent scale invariance of disordered horizons
We construct planar black hole solutions in AdS 3 and AdS 4 in which the boundary CFT is perturbed by marginally relevant quenched disorder. We show that the entropy density of the horizon has the scaling temperature dependence s ∼ T (d−1)/z (with d = 2, 3). The dynamical critical exponent z is computed numerically and, at weak disorder, analytically. These results lend support to the claim that the perturbed CFT flows to a disordered quantum critical theory in the IR
Utilização do efeito macho para induzir e sincronizar os estros (Cios) de fêmeas ovinas.
Introdução. Ciclo reprodutivo de ovelha. Efeito macho e fisiologia reprodutiva de ovinos. Efeito macho e a concentração de parições em regiões com diferentes latitudes. Sincronização dos estros (Cios) em ovelhas. Indução do estro (Cio) no período de anestro sazonal. Considerações finais.bitstream/item/78022/1/Cristiane-Sa-CTE99.pd
Estimativas de custos de instalação e manutenção de cerca elétrica solar, como divisória de pastagem, no estado do Acre.
O elevado custo das cercas tradicionais, compostas basicamente por estacas e mourões de madeira e arame farpado, fez surgir uma crescente demanda por cercas elétricas como divisórias de pastagem, no processo de intensificação do sistema de produção. O objetivos deste estudo foi estimar o custo de instalação e manutenção de cercas elétricas divisórias de pastagem na região próxima ao município de Rio Branco, Acre, considerando-se os equipamentos disponíveis no mercado local.bitstream/CPAF-AC/3679/1/comunicado120.pd
Lessons from monochorionic twin delivery
The presence of acute peripartum anaemia in a monochorionic twin pregnancy represents a clinical challenge requiring prompt recognition and management. Twin-to-twin transfusion syndrome (TTTS) is a major complication of these pregnancies and a medical emergency in its acute form. Acute intrapartum fetoplacental transfusion (AIFT) has been reported infrequently. The authors present a case of a probable acute TTTS in an uneventful monochorionic monoamnionic twin pregnancy, where typical ultrasound criteria for long-standing TTTS were absent. The first twin was born pale, hypotonic and developed hypovolemic shock due to acute anaemia. Soon after birth, she presented with seizures and a cerebral ultrasound detected a large parieto-occipital infarction. The second twin, although plethoric, was clinically well. The risk of acute TTTS and AIFT, although infrequent and unpredictable, should be kept in mind when planning delivery of monochorionic twins, because the consequences for one or both twins can be disastrous
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