Optical investigations of the chemical pressurized EuFe2(As1-xPx)2: an s-wave superconductor with strong interband interaction

Superconducting EuFe2(As0.82P0.18)2 single crystals are investigated by infrared spectroscopy in a wide frequency range. Below Tc=28K a superconducting gap forms at 2\Delta_{0} = 9.5 meV = 3.8 k_B T_c causing the reflectivity to sharply rise to unity at low frequency. In the range of the gap the optical conductivity can be perfectly described by BCS theory with an $s$-wave gap and no nodes. From our analysis of the temperature dependent conductivity and spectral weight at T>T_c, we deduce an increased interband coupling between hole- and electron-sheets on the Fermi surface when $T$ approaches T_c

Preheating after multifield inflation with nonminimal couplings, II: Resonance Structure

This is the second in a series of papers on preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. In this paper, we work in the rigid-spacetime approximation and consider field trajectories within the single-field attractor, which is a generic feature of these models. We construct the Floquet charts to find regions of parameter space in which particle production is efficient for both the adiabatic and isocurvature modes, and analyze the resonance structure using analytic and semi-analytic techniques. Particle production in the adiabatic direction is characterized by the existence of an asymptotic scaling solution at large values of the nonminimal couplings, $\xi_I \gg 1$, in which the dominant instability band arises in the long-wavelength limit, for comoving wavenumbers $k \rightarrow 0$. However, the large-$\xi_I$ regime is not reached until $\xi_I \geq {\cal O} (100)$. In the intermediate regime, with $\xi_I \sim {\cal O}(1 - 10)$, the resonance structure depends strongly on wavenumber and couplings. The resonance structure for isocurvature perturbations is distinct and more complicated than its adiabatic counterpart. An intermediate regime, for $\xi_I \sim {\cal O} (1 - 10)$, is again evident. For large values of $\xi_I$, the Floquet chart consists of densely spaced, nearly parallel instability bands, suggesting a very efficient preheating behavior. The increased efficiency arises from features of the nontrivial field-space manifold in the Einstein frame, which itself arises from the fields' nonminimal couplings in the Jordan frame, and has no analogue in models with minimal couplings. Quantitatively, the approach to the large-$\xi_I$ asymptotic solution for isocurvature modes is slower than in the case of the adiabatic modes.Comment: 46 pages, 23 figures. References added and minor edits made to match published versio

Preheating after multifield inflation with nonminimal couplings, III: Dynamical spacetime results

This paper concludes our semi-analytic study of preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. Using the covariant framework of paper I in this series, we extend the rigid-spacetime results of paper II by considering both the expansion of the universe during preheating, as well as the effect of the coupled metric perturbations on particle production. The adiabatic and isocurvature perturbations are governed by different effective masses that scale differently with the nonminimal couplings and evolve differently in time. The effective mass for the adiabatic modes is dominated by contributions from the coupled metric perturbations immediately after inflation. The metric perturbations contribute an oscillating tachyonic term that enhances an early period of significant particle production for the adiabatic modes, which ceases on a time-scale governed by the nonminimal couplings $\xi_I$. The effective mass of the isocurvature perturbations, on the other hand, is dominated by contributions from the fields' potential and from the curvature of the field-space manifold (in the Einstein frame), the balance between which shifts on a time-scale governed by $\xi_I$. As in papers I and II, we identify distinct behavior depending on whether the nonminimal couplings are small ($\xi_I \lesssim {\cal O} (1)$), intermediate ($\xi_I \sim {\cal O} (1 - 10)$), or large ($\xi_I \geq 100$).Comment: 34 pages, 11 figures. References added and minor edits made to match published versio

Review of the regulation of veterinary drugs and residues in South Africa

Published ArticleThe food safety risk analysis framework of the FAO/WHO is used in the review of veterinary drug and residue regulation in South Africa to determine possible inefficiencies within this system. Results indicate that a variety of challenges relating to the processes of risk assessment, management, and communication do exist, although these occur within a fragmented system of legislation, functions, and structures. Addressing these challenges therefore requires a change to a more collaborative and integrated system. It is indicated that for such a change, the underlying challenges of inadequate horizontal communication, poor conceptualization, and awareness of functions of the system are required to be dealt with

The social determinants of tuberculosis and their association with TB/HIV co-infection in Lusaka, Zambia

Introduction: Tuberculosis (TB) is a major public health problem globally.Progress made in TB control through the implementation of the DOTS strategy, has been retarded by factors such as poverty, the HIV pandemic and the advent of multidrug resistant tuberculosis. There is currently an increasing shift in TB control strategies to emphasize the importance of social determinants of TB if notable impact has to be attained. However, limited data exist that describe these determinants in high burden settings such as Zambia. This study was conducted to explore the social determinants of TB and their association with TB/HIV co-infection, in order to inform TB control strategies that would lead to appropriate action for impact.Method: A cross-section study of TB patients presenting to four peri-urban health facilities in Lusaka through administration of a standard structured questionnaire. STATA 12 Version 1 was used for analysis.Results: There were 1,259 TB patients enrolled. The median age was 35 (IQR; 29 – 41). The main determinants that were associated with TB/HIV co-infection were: being in the age-group 24-49 (p = 0.0001); being female (p = 0.0001); re-treatment (p = 0.0001); having extrapulmonary TB (p = 0.02); being married or widowed (p = 0.05 and p = 0.01, respectively)Conclusions: Describing the social determinants of TB and their association with TB/HIV co-infection highlighted a number of opportunities to strengthen control beyond the Stop TB Strategy

Characterization and Local Perceptions of Poverty Among Rural Households in Northern Zambia

Background: Poverty has been linked with poor  health outcomes in world health reports and cited by many scholars and leading health economists and public health specialist as a cause for poor health seeking behaviours especially for the rural poor. Poverty and ill-health are so closely intertwined that it is possible to use the words interchangeably, and still mean the same thing. Poverty has been defined as “a state of relative equilibrium of body form and function which results from its successful dynamic adjustments to forces tending to disturb it. It is not a passive interplay between body and forces impinging upon it but an active response of body forces working towards readjustment”. Poverty on the other hand has been defined as a “lack of access to income, employment, and normal internal entitlements for the citizens to such things as freely determined consumption of goods and services, shelter and other basic needs of life”. The poverty and ill-health situation has grown grimmer for Africa and some Asian countries. The last decade has seen an emergence of new and a resurgence of old infections with a virulence and velocity hard to compare. East Asia and Sub-Saharan Africa have been at the receiving end of most the consequences of poverty and the ill health that result exacerbated by the HIV and AIDS pandemic. It has been suggested that attacking poverty is the answer to better health. Many agree with this notion of improving health. The million dollar question has however remained how to proceed with the war against poverty. Experts and scholars have done commendable work studying, defining and designing solutions for poverty. That much has been achieved in these lines, again there is no denying. Success in reducing poverty has however remained elusive, especially in sub-Saharan Africa. World Health Organisation (WHO) in its World Health Report for 2005, admits failure in improvement of most health indicators in sub-Saharan Africa and more so for Zambia.Methods: The participatory action research (PAR) was conducted in Chikoti village in Luwingu area among 212 households, Kungu village in Kasama with 236 households, Mpepo village in Mpika with 220 households and Ilondola village with 360 households. The study investigated the relationship between poverty and ill-health and how the rural poor respond to this discourse.Results: The communities demonstrated a clear understanding of their own environment and were able to define factors which make them vulnerable to poverty and inversely to poor health. The study communities were able to distinctly define their own poverty levels and identify the categories of community members into the poverty status that is: managing poor, moderately poor and the extremely poor according to their local conditions and in their own local language.Conclusion: It is clear from the study findings that the rural communities do perceive poverty to affect all of the community members equally regardless of age or education levels. The study participants also demonstrated that they understood the vulnerability of women and children to poverty and its effects. It was also observed that poverty stricken communities often give preference to food than health, introducing ill-health due to negligence

CUTANEOUS ANGIITIS (VASCULITIS)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66185/1/j.1365-4362.1978.tb06119.x.pd