9,256 research outputs found
Rural economic growth linkages and small scale poultry production: A survey of producers in KwaZulu-Natal
This study analyses survey data gathered from small and large poultry producers in the rural areas of KwaZulu-Natal, and highlights factors constraining the impact of commercial poultry production on the local economy. It was found that small-scale poultry production has the ability to initiate economic growth through the "export" of its products and to draw under-utilised resources such as labour into production. The impact of the subsequent multiplier effect is most likely strongest in the non-tradable, non-agricultural sector. Alleviating constraints for a large number of small enterprises is expected to impact more positively on the rural economy than if a few larger enterprises were encouraged to grow bigger. The descriptive results suggest that small producers face much higher transaction costs than larger producers. Government policies should focus on absorbing some of these transaction costs to nurture economic growth in the rural areas of KwaZulu-Natal, i.e. by improving education, physical infrastructure and technology transfer through extension. Other important interventions include the provision of mentoring and training services for new managers including institution, legal and financial management instruction.Livestock Production/Industries,
Modelling the influence of the process inputs on the removal of surface contaminants from Ti-6Al-4V linear friction welds
The linear friction welding (LFW) process is finding increasing interest from industry for the fabrication of near-net-shape, titanium alloy Ti–6Al–4V, aerospace components. Currently, the removal of surface contaminants, such as oxides and foreign particles, from the weld interface into the flash is not fully understood. To address this problem, two-dimensional (2D) computational models were developed using the finite element analysis (FEA) software DEFORM and validated with experiments. The key findings showed that the welds made with higher applied forces required less burn-off to completely remove the surface contaminants from the interface into the flash; the interface temperature increased as the applied force was decreased or the rubbing velocity increased; and the boundary temperature between the rapid flash formation and negligible material flow was approximately 970 °C. An understanding of these phenomena is of particular interest for the industrialisation of near-net-shape titanium alloy aerospace components.EPSRC, Boeing Company, Welding Institut
Modelling of the workpiece geometry effects on Ti–6Al–4V linear friction welds
Linear friction welding (LFW) is a solid-state joining process that is finding increasing interest from industry for the fabrication of titanium alloy (Ti–6Al–4V) preforms. Currently, the effects of the workpiece geometry on the thermal fields, material flow and interface contaminant removal during processing are not fully understood. To address this problem, two-dimensional (2D) computational models were developed using the finite element analysis (FEA) software DEFORM and validated with experiments. A key finding was that the width of the workpieces in the direction of oscillation (in-plane width) had a much greater effect on the experimental weld outputs than the cross-sectional area. According to the validated models, a decrease of the in-plane width increased the burn-off rate whilst decreasing the interface temperature, TMAZ thickness and the burn-off required to remove the interface contaminants from the weld into the flash. Furthermore, the experimental weld interface consisted of a Widmanstätten microstructure, which became finer as the in-plane width was reduced. These findings have significant, practical benefits and may aid industrialisation of the LFW process.The authors would like to thank the Engineering and Physical Sciences
Research Council (EPSRC), The Boeing Company and The Welding
Institute (TWI) for funding the research presented in this paper
Ultraviolet avalanche in anisotropic non-Abelian plasmas
We present solutions of coupled particle-field evolution in classical U(1)
and SU(2) gauge theories in real time on three-dimensional lattices. For
strongly anisotropic particle momentum distributions, we find qualitatively
different behavior for the two theories when the field strength is high enough
that non-Abelian self-interactions matter for SU(2). It appears that the energy
drained by a Weibel-like plasma instability from the particles does not build
up exponentially in transverse magnetic fields but instead returns,
isotropically, to the hard scale via a rapid avalanche into the ultraviolet.Comment: 22 pages, 10 figures; v3: small textual changes; updated to
correspond with version to appear in publicatio
Growth dynamics of a Bose-Einstein condensate in a dimple trap without cooling
We study the formation of a Bose-Einstein condensate in a cigar-shaped
three-dimensional harmonic trap, induced by the controlled addition of an
attractive "dimple" potential along the weak axis. In this manner we are able
to induce condensation without cooling due to a localized increase in the phase
space density. We perform a quantitative analysis of the thermodynamic
transformation in both the sudden and adiabatic regimes for a range of dimple
widths and depths. We find good agreement with equilibrium calculations based
on self-consistent semiclassical Hartree-Fock theory describing the condensate
and thermal cloud. We observe there is an optimal dimple depth that results in
a maximum in the condensate fraction. We also study the non-equilibrium
dynamics of condensate formation in the sudden turn-on regime, finding good
agreement for the observed time dependence of the condensate fraction with
calculations based on quantum kinetic theory.Comment: v1: 9 pages, 7 figures, submitted to Phys. Rev. A; v2: 10 pages, 8
figures, fixed typos, added references, additional details on experimental
procedure, values of phase-space density, new figure and discussion on
effects of three-body loss in Appendix B (replaced with published version
The tight skin mouse: demonstration of mutant fibrillin-1 production and assembly into abnormal microfibrils
Mice carrying the Tight skin (Tsk) mutation harbor a genomic duplication within the fibrillin-1 (Fbn 1) gene that results in a larger than normal in-frame Fbn 1 transcript. In this study, the consequences of the Tsk mutation for fibrillin-containing microfibrils have been examined. Dermal fibroblasts from Tsk/+ mice synthesized and secreted both normal fibrillin (approximately 330 kD) and the mutant oversized Tsk fibrillin-1 (approximately 450 kD) in comparable amounts, and Tsk fibrillin-1 was stably incorporated into cell layers. Immunohistochemical and ultrastructural analyses of normal and Tsk/+ mouse skin highlighted differences in the gross organization and distribution of microfibrillar arrays. Rotary shadowing of high Mr preparations from Tsk/+ skin demonstrated the presence of abundant beaded microfibrils. Some of these had normal morphology and periodicity, but others were distinguished by diffuse interbeads, longer periodicity, and tendency to aggregate. The presence of a structurally abnormal population of microfibrils in Tsk/+ skin was unequivocally demonstrated after calcium chelation and in denaturating conditions. Scanning transmission electron microscopy highlighted the presence of more mass in Tsk/+ skin microfibrils than in normal mice skin microfibrils. These data indicate that Tsk fibrillin-1 polymerizes and becomes incorporated into a discrete population of beaded microfibrils with altered molecular organization
Contemporary developments in Green (environmental) HRM scholarship
This article reviews the contemporary literature on Green Human Resource Management (GHRM) to contextually frame the seven articles appearing in this Special Issue. Review findings reveal the embedded nature of GHRM workplace-level practices and additional research needing to focus on HR systems, individual behaviors and emerging theoretical lenses. As a set, the articles herein span green recruitment, competencies, employee participation, financial/environmental performance links, and contextual issues utilizing national culture, paradox, and stakeholder theories. By recognizing such multi-level dynamics, HRM scholars and practitioners can enhance GHRM initiatives that stimulate progress toward workplace environmental sustainability.Full Tex
Energy and force analysis of Ti-6Al-4V linear friction welds for computational modeling input and validation data
The linear friction welding (LFW) process is finding increasing use as a manufacturing technology for the production of titanium alloy Ti-6Al-4V aerospace components. Computational models give an insight into the process, however, there is limited experimental data that can be used for either modeling inputs or validation. To address this problem, a design of experiments approach was used to investigate the influence of the LFW process inputs on various outputs for experimental Ti-6Al-4V welds. The finite element analysis software DEFORM was also used in conjunction with the experimental findings to investigate the heating of the workpieces. Key findings showed that the average interface force and coefficient of friction during each phase of the process were insensitive to the rubbing velocity; the coefficient of friction was not coulombic and varied between 0.3 and 1.3 depending on the process conditions; and the interface of the workpieces reached a temperature of approximately approximately 1273 K (1000 °C) at the end of phase 1. This work has enabled a greater insight into the underlying process physics and will aid future modeling investigations.EPSRC, Boeing Company, Welding Institut
Drug therapy for delirium in terminally ill adult patients.
BACKGROUND: Delirium is a syndrome characterised by a disturbance of consciousness (often fluctuating), cognition and perception. In terminally ill patients it is one of the most common causes of admission to clinical care. Delirium may arise from any number of causes and treatment should be directed at addressing these causes rather than the symptom cluster. In cases where this is not possible, or treatment does not prove successful, the use of drug therapy to manage the symptoms may become necessary. This is an update of the review published on 'Drug therapy for delirium in terminally ill adult patients' in The Cochrane Library 2004, Issue 2 ( Jackson 2004). OBJECTIVES: To evaluate the effectiveness of drug therapies to treat delirium in adult patients in the terminal phase of a disease. SEARCH METHODS: We searched the following sources: CENTRAL (The Cochrane Library 2012, Issue 7), MEDLINE (1966 to 2012), EMBASE (1980 to 2012), CINAHL (1982 to 2012) and PSYCINFO (1990 to 2012). SELECTION CRITERIA: Prospective trials with or without randomisation or blinding involving the use of drug therapies for the treatment of delirium in adult patients in the terminal phase of a disease. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality using standardised methods and extracted trial data. We collected outcomes related to efficacy and adverse effects. MAIN RESULTS: One trial met the criteria for inclusion. In the 2012 update search we retrieved 3066 citations but identified no new trials. The included trial evaluated 30 hospitalised AIDS patients receiving one of three agents: chlorpromazine, haloperidol and lorazepam. The trial under-reported key methodological features. It found overall that patients in the chlorpromazine group and those in the haloperidol group had fewer symptoms of delirium at follow-up (to below the diagnostic threshold using the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) and that both were equally effective (at two days mean difference (MD) 0.37; 95% confidence interval (CI) -4.58 to 5.32; between two and six days MD -0.21; 95% CI -5.35 to 4.93). Chlorpromazine and haloperidol were found to be no different in improving cognitive status in the short term (at 48 hours) but at subsequent follow-up cognitive status was reduced in those taking chlorpromazine. Improvements from baseline to day two for patients randomised to lorazepam were not apparent. All patients on lorazepam (n = 6) developed adverse effects, including oversedation and increased confusion, leading to trial drug discontinuation. AUTHORS' CONCLUSIONS: There remains insufficient evidence to draw conclusions about the role of drug therapy in the treatment of delirium in terminally ill patients. Thus, practitioners should continue to follow current clinical guidelines. Further research is essential
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