Nonlocal spectral properties of disordered alloys

A general method is proposed for calculating a fully k-dependent, continuous, and causal spectral function A(k,E) within the recently introduced nonlocal version of the coherent-potential approximation (NLCPA). The method involves the combination of both periodic and anti-periodic solutions to the associated cluster problem and also leads to correct bulk quantities for small cluster sizes. We illustrate the method by investigating the Fermi surface of a two-dimensional alloy. Dramatically, we find a smeared electronic topological transition not predicted by the conventional CPA.Comment: 17 pages, 5 figures, Submitted to: J. Phys.: Condens. Matter Editorial receipt 25 May 200

Process of Deinstitutionalization of Aging Individuals With Severe and Disabling Mental Disorders: A Review

BACKGROUND: For more than 60 years, psychiatric services has gradually gone from an asylum model to a community model. This change has led to the emergence of a deinstitutionalization movement. This movement seems to have left behind long-term hospitalized aging individuals with severe and disabling mental disorders. The objective of this article is to conduct a review on the challenges and issues associated with the process of deinstitutionalization among hospitalized aging individuals with severe and disabling mental disorders. METHODS: Using PRISMA statement, the research methodology was carried out in English and French in 16 databases with a combination of 3 lists of keywords. The selection process was then followed by a thematic analysis which aimed at categorizing by theme and classifying the writings selected. RESULTS: A total of 83 articles published between 1978 and 2019 were selected and organized into six categories: (a) a forgotten population in research and health policies, (b) an economic presentation of the deinstitutionalization process, (c) an improvement in quality of life and global functioning for deinstitutionalized patients (d) from stigmatization to the rejection of elderly psychiatric inpatients from deinstutionalization process, (e) a difficult community-based care offer and a difficult epistemological identification, (f) from the lack of community services to the phenomenon of transinstitutionalization. The current state of scientific research, institutional policies and clinical practices associated with the deinstitutionalization process of SVPTSIH are then commented. CONCLUSIONS: Recommendations are proposed to researchers and professionals concerned with the support of long-term hospitalized aging individuals with severe and disabling mental disorders

Existence of axially symmetric static solutions of the Einstein-Vlasov system

We prove the existence of static, asymptotically flat non-vacuum spacetimes with axial symmetry where the matter is modeled as a collisionless gas. The axially symmetric solutions of the resulting Einstein-Vlasov system are obtained via the implicit function theorem by perturbing off a suitable spherically symmetric steady state of the Vlasov-Poisson system.Comment: 32 page

Contested resources: unions, employers, and the adoption of new work practices in US and UK telecommunications

The pattern of adoption of high-performance work practices has been explained in terms of strategic contingency and in terms of union presence. We compare the post-deregulation/privatization changes in work practice at AT&T, Bell Atlantic and British Telecom. On the basis of these cases, we argue that the choice of new work practices should be understood as a consequence not only of the company's resources or changes in its environment, nor of a simple union presence, but also as a consequence of the practices' effects on union power, the nature of the union's engagement, and the union's strategic choices

Investigation of the nonlocal coherent-potential approximation

Recently the nonlocal coherent-potential approximation (NLCPA) has been introduced by Jarrell and Krishnamurthy for describing the electronic structure of substitutionally disordered systems. The NLCPA provides systematic corrections to the widely used coherent-potential approximation (CPA) whilst preserving the full symmetry of the underlying lattice. Here an analytical and systematic numerical study of the NLCPA is presented for a one-dimensional tight-binding model Hamiltonian, and comparisons with the embedded cluster method (ECM) and molecular coherent potential approximation (MCPA) are made.Comment: 18 pages, 5 figure

Thin-film flow in helically wound rectangular channels with small torsion

Laminar gravity-driven thin-film flow down a helically-wound channel of rectangular cross-section with small torsion in which the fluid depth is small is considered. Neglecting the entrance and exit regions we obtain the steady-state solution that is independent of position along the axis of the channel, so that the flow, which comprises a primary flow in the direction of the axis of the channel and a secondary flow in the cross-sectional plane, depends only on position in the two-dimensional cross-section of the channel. A thin-film approximation yields explicit expressions for the fluid velocity and pressure in terms of the free-surface shape, the latter satisfying a non-linear ordinary differential equation that has a simple exact solution in the special case of a channel of rectangular cross-section. The predictions of the thin-film model are shown to be in good agreement with much more computationally intensive solutions of the small-helix-torsion Navier–Stokes equations. The present work has particular relevance to spiral particle separators used in the mineral-processing industry. The validity of an assumption commonly used in modelling flow in spiral separators, namely that the flow in the outer region of the separator cross-section is described by a free vortex, is shown to depend on the problem parameters

Thin-film flow in helically wound shallow channels of arbitrary cross-sectional shape

We consider the steady, gravity-driven flow of a thin film of viscous fluid down a helically wound shallow channel of arbitrary cross-sectional shape with arbitrary torsion and curvature. This extends our previous work [D. J. Arnold et al., “Thin-film flow in helically-wound rectangular channels of arbitrary torsion and curvature,” J. Fluid Mech. 764, 76–94 (2015)] on channels of rectangular cross section. The Navier-Stokes equations are expressed in a novel, non-orthogonal coordinate system fitted to the channel bottom. By assuming that the channel depth is small compared to its width and that the fluid depth in the vertical direction is also small compared to its typical horizontal extent, we are able to solve for the velocity components and pressure analytically. Using these results, a differential equation for the free surface shape is obtained, which must in general be solved numerically. Motivated by the aim of understanding flows in static spiral particle separators used in mineral processing, we investigate the effect of cross-sectional shape on the secondary flow in the channel cross section. We show that the competition between gravity and inertia in non-rectangular channels is qualitatively similar to that in rectangular channels, but that the cross-sectional shape has a strong influence on the breakup of the secondary flow into multiple clockwise-rotating cells. This may be triggered by small changes to the channel geometry, such as one or more bumps in the channel bottom that are small relative to the fluid depth. In contrast to the secondary flow which is quite sensitive to small bumps in the channel bottom, the free-surface profile is relatively insensitive to these. The sensitivity of the flow to the channel geometry may have important implications for the design of efficient spiral particle separators.D. J. Arnold, Y. M. Stokes, and J. E. F. Gree

Factors affecting farmers’ adoption of natural farming technologies in New Albay, Maragusan, Compostela Valley, Philippines

In the Philippines, the sustainability of natural resources and the profitability of farming has become a major concern for smallholder farmers. To address these concerns, government agencies and the private sector are delivering workshops on natural farming technologies to farmers. Training includes the preparation of different concoctions such as indigenous micro-organisms (IMO), fermented fruit juice (FFJ) and fermented plant juice (FPJ), fish amino acid (FAA), oriental herbal juice (OHN) and calcium phosphate (Caphos). Other natural farm technologies include vermiculture. The products from the training are applied to the farmer’s own farms with any surplus products sold to other farmers. In Maragusan, Compostela Valley, Philippines, a group of smallholder farmers have successfully produced organic fertilizers as a result of the training provided to them. Initially, while training was provided to the group to facilitate the marketing of the fresh vegetable crops they produced, the skills learnt were readily transferable. This study discusses the development of the New Albay cluster and factors leading to its decline as a marketing cluster. This study will also explore the costs and returns associated with the application of organic fertilizer to vegetable crops in comparison to conventional farming practices. Results show that the cost of production arising from the use of natural farming technologies is lower than conventional farming

Social connections and smallholder vegetable farmers’ collaborative marketing strategy: The case of the small farmers association of Quirogpang in Davao City, the Philippines

In the Philippines, vegetable farmers generally have only small land holdings. Because of this, plus an apparent lack of financial capital, it is difficult for smallholder farmers to meet the large volume demands imposed by institutional buyers and wholesalers. The small volume and the large variation in quality puts smallholder farmers at a significant disadvantage when it comes to arranging transport and marketing. However, smallholder farmers can engage in collaborative cluster farming in order to meet the demands of the market and to bolster production volume. In the cluster, the farmers carry out production planning and marketing activities collectively. Utilizing the case study method and the 8-step clustering approach formulated by the Catholic Relief Services, this paper will present key success factors and several challenges faced by the Small Farmers Association of Quirogpang (SFAQ) in Marilog, Davao City, Philippines. At the same time, it will identify important institutional supports and strategies that may enhance the success of this and other clusters. The paper highlights key success factors such as the social connections shared by the cluster members and leadership. In this case, these commonalities exist because it is an area-based cluster which includes neighbours and relatives who all practice one religion and speak the same language or dialect