Social Support and the Perception of Geographical Slant.

The visual perception of geographical slant is influenced by physiological resources, such as physical fitness, age, and being physically refreshed. In two studies we tested whether a psychosocial resource, social support, can also affect the visual perception of slants. Participants accompanied by a friend estimated a hill to be less steep when compared to participants who were alone (Study 1). Similarly, participants who thought of a supportive friend during an imagery task saw a hill as less steep than participants who either thought of a neutral person or a disliked person (Study 2). In both studies, the effects of social relationships on visual perception appear to be mediated by relationship quality (i.e., relationship duration, interpersonal closeness, warmth). Artifacts such as mood, social desirability, and social facilitation did not account for these effects. This research demonstrates that an interpersonal phenomenon, social support, can influence visual perception

Thermally Induced Losses in Ultra-Cold Atoms Magnetically Trapped Near Room-Temperature Surfaces

We have measured magnetic trap lifetimes of ultra-cold Rb87 atoms at distances of 5-1000 microns from surfaces of conducting metals with varying resistivity. Good agreement is found with a theoretical model for losses arising from near-field magnetic thermal noise, confirming the complications associated with holding trapped atoms close to conducting surfaces. A dielectric surface (silicon) was found in contrast to be so benign that we are able to evaporatively cool atoms to a Bose-Einstein condensate by using the surface to selectively adsorb higher energy atoms.Comment: Improved theory curve eliminates discrepancy. JLTP in pres

The Mystery of the Ramsey Fringe that Didn't Chirp

We use precision microwave spectroscopy of magnetically trapped, ultra-cold 87Rb to characterize intra- and inter-state density correlations. The cold collision shifts for both normal and condensed clouds are measured. The results verify the presence of the sometimes controversial "factors of two", in normal-cloud mean-field energies, both within a particular state and between two distinct spin species. One might expect that as two spin species decohere, the inter-state factor of two would revert to unity, but the associated frequency chirp one naively expects from such a trend is not observed in our data.Comment: Proceedings of the 18th International Conference on Atomic Physics (ICAP 2002

Decoherence-driven Cooling of a Degenerate Spinor Bose Gas

We investigate the relationship between the coherence of a partially Bose-condensed spinor gas and its temperature. We observe cooling of the normal component driven by decoherence as well the effect of temperature on decoherence rates.Comment: 4 pages, 2 figure

The commercialist identity of mid-tier firm auditors: A precarious balancing of priorities

Purpose: This paper aims to extend our understanding of how mid-tier firm auditors legitimise and institutionalise the logic of commercialism within their profession. This paper is responsive to research that shows how Big Four auditors have restructured the market and re-cast the relationality between the two logics to forge an identity that suits them commercially. Such research provides insight into auditor agency and intentionality, illustrating how auditors maintain and indeed grow their status and role within society. Design/methodology/approach: Semi-structured interviews with audit executives situated in a strategically challenging regulatory context are interpreted through a theoretical framework developed from institutional complexity theory, coupled with the understanding that institutional logics are a socially constructed phenomenon. Findings: Mid-tier auditors appear to be as commercially orientated as their Big Four counterparts, expressing the logics of professionalism and commercialism as highly complementary. In response to competitive pressures and the difficulty of replicating the multi-disciplinary practice business model of the Big Four, mid-tier auditors present a competitive and contrasting identity as “more devoted experts”, using various legitimation techniques and “heroic” representations. This identity representation is strategic, allowing them to forge a consistent and coherent “collective identity defining story” designed to counter the “versatile expert” identity of the Big Four and establish social legitimacy with their potential client base. Originality/value: These findings contribute to our understanding of how mid-tier auditors are “catching up” to the Big Four in the construction of their commercial business model. By shedding light on the rhetoric and “identity experimentation” of auditors, the findings can aid legislators and regulators to exercise democratic control over the profession and promulgate regulations that better align auditors’ interests with the public interest. As regulators encourage mid-tier firms to compete with the Big Four and lower supply concentration in the market, this study believes the tensions inherent in the logics, as well as the strategic necessity for firms to represent themselves in a favourable manner, will become more prominent

Schooling for violence and peace : how does peace education differ from ‘normal’ schooling?

This article reviews literature on the roles of schooling in both reproducing and actively perpetrating violence, and sets out an historical explanation of why schools are socially constructed in such a way as to make these roles possible. It then discusses notions of peace education in relation to one particular project in England before using empirical data from research on the project to examine contrasts between peace education approaches and ‘normal’ schooling from the viewpoints of project workers, pupils and teachers. It concludes that such contrasts and tensions do indeed exist and that this raises serious questions about the compatibility of peace education and formal schooling

Theory of the Ramsey spectroscopy and anomalous segregation in ultra-cold rubidium

The recent anomalous segregation experiment of Lewandowski et al. (PRL, 88, 070403, 2002) shows dramatic, rapid internal state segregation for two hyperfine levels of rubidium. We simulate an effective one dimensional model of the system for experimental parameters and find reasonable agreement with the data. The Ramsey frequency is found to be insensitive to the decoherence of the superposition, and is only equivalent to the interaction energy shift for a pure superposition. A Quantum Boltzmann equation describing collisions is derived using Quantum Kinetic Theory, taking into account the different scattering lengths of the internal states. As spin-wave experiments are likely to be attempted at lower temperatures we examine the effect of degeneracy on decoherence by considering the recent experiment of Lewandowski et al. where degeneracy is around 10%. We also find that the segregation effect is only possible when transport terms are included in the equations of motion, and that the interactions only directly alter the momentum distributions of the states. The segregation or spin wave effect is thus entirely due to coherent atomic motion as foreseen in the experimental reportComment: 26 pages, 4 figures, to be published in J. Phys.

Spectroscopic insensitivity to cold collisions in a two-state mixture of fermions

We have experimentally demonstrated the absence of spectroscopic resonance shifts in a mixture of two interacting Fermi gases. This result is linked to observations in an ultracold gas of thermal bosons. There, the measured resonance shift due to interstate collisions is independent of the coherence in the system, and twice that expected from the equilibrium energy splitting between the two states in a fully decohered cloud. We give a simple theoretical explanation of these observations, which elucidates the effect of coherent radiation on an incoherent mixture of atoms

Studies of Photoprotection Against Porphyrin Photosensitization Using Dithiothreitol and Glycerol

Although protection against ionizing radiation by compounds containing sulfhydryl (SN) groups, such as cysteine, has been reported, these agents have been unsuccessful to date in protecting mammals against non-ionizing radiation (>200nm). This study describes successful photoprotection by dithiothreitol (DTT) and glycerol against porphyrin photosensitization having an action spectrum of 400nm. Test models used were red blood cells (RBC) obtained from patients with erythropoietic protoporphyria (EPP) and mice photo-sensitized by hematoporphyrin (HP). A mortality rate approaching a lethal dose in 50% of the animals in 1 day (LD50/24 hrs) was established in 100 white mice that had received an intraperitoneal injection of 100mg HP/kg body wt., and were then irradiated with 5 × 106 ergs/cm2 from a fluorescent light source emitting 320-450nm radiation. Another 100 mice were treated in an identical manner except that they received, in addition to HP, 80mg DTT/kg body weight in a 5.5% glycerol solution. This group showed 75% reduction in mortality (p < 0.03). No lethal effects were observed in animals treated with DTT and glycerol or HP in the above concentrations without 400nm irradiation. RBC obtained from patients with EPP and exposed to 107 ergs/mm2 of 400nm radiation showed 100% hemolysis after 180min. These cells, when irradiated under identical conditions except for the addition of DTT, manifested only 19% hemolysis during this period of time. Measurements of SH groups of RBC from patients with EPP showed a progressive decrease during photohemolysis. Comparison of the rate of photohemolysis of normal and glucose-6-phosphate dehydrogenase (G6PD) deficient RBC irradiated in the presence of protoporphyrin IX revealed that G6PD deficient RBC, which have an impaired ability to produce reduced glutathione (GSH), were more susceptible to porphyrin-induced photohemolysis. These studies demonstrate that DTT and glycerol offer photoprotection in an in vivo mammalian system against porphyrin photosensitization. It is suggested that the mechanism of the photoprotective action against 320-450nm radiation has many features similar to that of radioprotection by thiols and glycerol against ionizing radiation

Discrete-step evaporation of an atomic beam

We present a theoretical analysis of the evaporative cooling of a magnetically guided atomic beam by means of discrete radio-frequency antennas. First we derive the changes in flux and temperature, as well as in collision rate and phase-space density, for a single evaporation step. Next we show how the occurrence of collisions during the propagation between two successive antennas can be probed. Finally, we discuss the optimization of the evaporation ramp with several antennas to reach quantum degeneracy. We estimate the number of antennas required to increase the phase-space density by several orders of magnitude. We find that at least 30 antennas are needed to gain a factor $10^8$ in phase-space density.Comment: Submitted to Eur. Phys. J.