3,274 research outputs found
Ethical dilemmas are not simply black and white
This is an Accepted Manuscript of an article published by Taylor & Francis Group in Ethics and Social Practice on 1 July 2008, available online at: http://dx.doi.org/10.1080/17496530801948838.This article aims to highlight some of the ethical issues that arise when social work educators plan to involve service users and carers from black and minority ethnic (BME) communities in the teaching of social work students. Between 2005 and 2007, the authors carried out a two-part project that involved working with service users and carers from BME communities in the area around Liverpool in Britain. The article first discusses the background for this two-part project, highlighting two themes relating to the ethical dilemmas we experienced. The first of these themes concerned conducting a project in a political context based on short and intermittent funding and intransigent bureaucracy. Our second theme concerned how to reconcile bringing together a group of people because they were recognized as having a shared experience while at the same time there were a myriad differences within the group. We then discuss these issues in light of the ethical approach we adopted, based on being open and honest, flexible in a respectful and meaningful way, and on anti-oppressive ethics and shared responsibility.Peer reviewe
Monte Carlo studies of Mott scattering asymmetries from gold foils
We present the results of a series of model Monte Carlo calculations of the scattering of spin-polarized electrons from gold foil targets. Our calculations examine the behavior of the left-right scattering asymmetry A as a function of various parameters conventionally used in extrapolation of the left-right asymmetry to single atom and/or elastic scattering conditions. These parameters include target thickness, scattered count rate, and the maximum energy that an electron can have lost in the target and still be detected. Data are obtained at incident electron energies of 10–120 keV, with detector-subtended half-cone angles of 5°, 10°, and 20°, and gold foils of average thickness varying from 3 to 1000Å. Both elastic and inelastic electron scattering effects have been considered. Comparisons of our results are made with existing measurements and theoretical models. We make recommendations concerning extrapolation algorithms and for future experiments to test the present Mott scattering Monte Carlo model
Engaging service users and carers in health and social care education: : challenges and opportunities in the Chinese Community
This is an accepted manuscript of an article published by Taylor & Francis Group in Social Work Education on 25 June 2010, available online at: http://dx.doi.org/10.1080/02615479.2010.491542.Service users' and carers' involvement in health and social care education has become a mainstream activity in Britain. However, members from black and minority ethnic communities (BME) remain under-represented in this area of participation. In this article, we will take the readers across the globe to explore the difficulties and opportunities of engaging such an under-represented group, the Chinese community. The journey will begin in Britain where barriers to engagement of service users and carers from the Chinese community will be discussed. We will then travel to Hong Kong, a cosmopolitan city, where successful engagement in work with Chinese service users and carers will be explored. Throughout the journey, we will highlight the importance of the consideration of cultural factors, particularly Confucian beliefs such as social harmony and collectivism, when working with Chinese people. We will also fully explore the issue of ‘trust’ as a culturally laden concept in Chinese societies and its significance for successful engagement in work with Chinese service users and carers in different parts of the world.Peer reviewedFinal Accepted Versio
Deterministic Soluble Model of Coarsening
We investigate a 3-phase deterministic one-dimensional phase ordering model
in which interfaces move ballistically and annihilate upon colliding. We
determine analytically the autocorrelation function A(t). This is done by
computing generalized first-passage type probabilities P_n(t) which measure the
fraction of space crossed by exactly n interfaces during the time interval
(0,t), and then expressing the autocorrelation function via P_n's. We further
reveal the spatial structure of the system by analyzing the domain size
distribution.Comment: 5 pages, RevTeX fil
Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC
We present the first measurements of the double spin asymmetries A_NN and
A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized
proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were
collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The
measured asymmetries, which are consistent with zero, allow us to estimate
upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t
as well as on the difference Delta(sigma_T) between the total cross sections
for transversely polarized protons with antiparallel or parallel spin
orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.
Overall time evolution in phase-ordering kinetics
The phenomenology from the time of the quench to the asymptotic behavior in
the phase-ordering kinetics of a system with conserved order parameter is
investigated in the Bray-Humayun model and in the Cahn-Hilliard-Cook model.
From the comparison of the structure factor in the two models the generic
pattern of the overall time evolution, based on the sequence ``early linear -
intermediate mean field - late asymptotic regime'' is extracted. It is found
that the time duration of each of these regimes is strongly dependent on the
wave vector and on the parameters of the quench, such as the amplitude of the
initial fluctuations and the final equilibrium temperature. The rich and
complex crossover phenomenology arising as these parameters are varied can be
accounted for in a simple way through the structure of the solution of the
Bray-Humayun model.Comment: RevTeX, 14 pages, 18 figures, to appear in Phys. Rev.
Networking - A Statistical Physics Perspective
Efficient networking has a substantial economic and societal impact in a
broad range of areas including transportation systems, wired and wireless
communications and a range of Internet applications. As transportation and
communication networks become increasingly more complex, the ever increasing
demand for congestion control, higher traffic capacity, quality of service,
robustness and reduced energy consumption require new tools and methods to meet
these conflicting requirements. The new methodology should serve for gaining
better understanding of the properties of networking systems at the macroscopic
level, as well as for the development of new principled optimization and
management algorithms at the microscopic level. Methods of statistical physics
seem best placed to provide new approaches as they have been developed
specifically to deal with non-linear large scale systems. This paper aims at
presenting an overview of tools and methods that have been developed within the
statistical physics community and that can be readily applied to address the
emerging problems in networking. These include diffusion processes, methods
from disordered systems and polymer physics, probabilistic inference, which
have direct relevance to network routing, file and frequency distribution, the
exploration of network structures and vulnerability, and various other
practical networking applications.Comment: (Review article) 71 pages, 14 figure
Renormalization Group Study of the A+B->0 Diffusion-Limited Reaction
The diffusion-limited reaction, with equal initial densities
, is studied by means of a field-theoretic renormalization
group formulation of the problem. For dimension an effective theory is
derived, from which the density and correlation functions can be calculated. We
find the density decays in time as a,b \sim C\sqrt{\D}(Dt)^{-d/4} for , with \D = n_0-C^\prime n_0^{d/2} + \dots, where is a universal
constant, and is non-universal. The calculation is extended to the
case of unequal diffusion constants , resulting in a new
amplitude but the same exponent. For a controlled calculation is not
possible, but a heuristic argument is presented that the results above give at
least the leading term in an expansion. Finally, we address
reaction zones formed in the steady-state by opposing currents of and
particles, and derive scaling properties.Comment: 17 pages, REVTeX, 13 compressed figures, included with epsf. Eq.
(6.12) corrected, and a moderate rewriting of the introduction. Accepted for
publication in J. Stat. Phy
Experimental Study on Sand Transport Characteristics in Horizontal and Inclined Two-Phase Solid-Liquid Pipe Flow
An experimental investigation on the hydraulic transport of sand particles in pipelines is presented in both horizontal and 30° upward inclined orientations. The pipe, with an internal diameter of 0.0254 m, had sand transported in various water superficial velocities at low and high sand concentrations [0.1%–10% volume-to-volume ratio (v/v)]. Sand particles were polydisperse (144–250 μm) with
Synthesis and Storage Stability of Diisopropylfluorophosphate
Diisopropylfluorophosphate (DFP) is a potent acetylcholinesterase inhibitor commonly used in toxicological studies as an organophosphorus nerve agent surrogate. However, LD50 values for DFP in the same species can differ widely even within the same laboratory, possibly due to the use of degraded DFP. The objectives here were to identify an efficient synthesis route for high purity DFP and assess the storage stability of both the in-house synthesized and commercial source of DFP at the manufacturer-recommended storage temperature of 4°C, as well as −10°C and −80°C. After 393 days, the commercial DFP stored at 4°C experienced significant degradation, while only minor degradation was observed at −10°C and none was observed at −80°C. DFP prepared using the newly identified synthesis route was significantly more stable, exhibiting only minor degradation at 4°C and none at −10°C or −80°C. The major degradation product was the monoacid derivative diisopropylphosphate, formed via hydrolysis of DFP. It was also found that storing DFP in glass containers may accelerate the degradation process by generating water in situ as hydrolytically generated hydrofluoric acid attacks the silica in the glass. Based on the results here, it is recommended that DFP be stored at or below −10°C, preferably in air-tight, nonglass containers
- …