Informal helpers : an exploratory study of a role and its contexts.

PsychologyDoctor of Philosophy (PhD

Political ideology and personality correlates of college students and their response to a request for helping behavior from a politically biased recruiter.

The purpose of the present study was to compare nonactivist students, of both left and right political ideologies, on a behavioral measure that would assess, in part, their humanitarian concerns and their valuation of social . expectancies. To date, the literature concerning both student activism and ideology has been almost entirely confined to the use of questionnaires, checklists, and other paper-and-pencil techniques. Results from these studies have indicated that student left activists were often found to have a more positive personality profile than nonactivist student cross sectional samples. Later investigations pointed out, however, that due to serious methodological and procedural confounding, many of the personality characteristics previously ascribed solely to student left activists may either apply to all left oriented students or to all activist students, regardless of ideology

Stimulation of bioprocesses by ultrasound

Ultrasound (US) has become a ubiquitous technological process in a large variety of scientific disciplines. However, little information exists on the use of ultrasound to enhance biological processes and/or processing and consequently this paper provides an overview of work reported to date on this topic. This review provides a brief introduction to ultrasound and the history of ultrasound as applied to bioprocesses. This is followed by a discussion of the influence of US on discrete enzyme systems, enzymes used in bioremediation, microbial fermentations and enzymatic hydrolysis of biopolymers. Augmentation of anaerobic digestion by US is then considered along with enhancement of enzymes in food science and technology. The use of ultrasonically stimulated enzymes in synthesis is then considered and other relevant miscellaneous topics are described. It is concluded that the precise mechanism of action of US in bio-processing remains to be elucidated though a variety of plausible suggestions are made

Exit Mechanisms of the Intracellular Bacterium Ehrlichia

Background: The obligately intracellular bacterium Ehrlichia chaffeensis that resides in mononuclear phagocytes is the causative agent of human monocytotropic ehrlichiosis. Ehrlichia muris and Ixodes ovatus Ehrlichia (IOE) are agents of mouse models of ehrlichiosis. The mechanism by which Ehrlichia are transported from an infected host cell to a non-infected cell has not been demonstrated. Methodology/Principal Findings: Using fluorescence microscopy and transmission and scanning electron microscopy, we demonstrated that Ehrlichia was transported through the filopodia of macrophages during early stages of infection. If host cells were not present in the vicinity of an Ehrlichia-infected cell, the leading edge of the filopodium formed a fan-shaped structure filled with the pathogen. Formation of filopodia in the host macrophages was inhibited by cytochalasin D and ehrlichial transport were prevented due to the absence of filopodia formation. At late stages of infection the host cell membrane was ruptured, and the bacteria were released. Conclusions/Significance: Ehrlichia are transported through the host cell filopodium during initial stages of infection, but are released by host cell membrane rupture during later stages of infection

Short-term genome stability of serial Clostridium difficile ribotype 027 isolates in an experimental gut model and recurrent human disease

Copyright: © 2013 Eyre et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedClostridium difficile whole genome sequencing has the potential to identify related isolates, even among otherwise indistinguishable strains, but interpretation depends on understanding genomic variation within isolates and individuals.Serial isolates from two scenarios were whole genome sequenced. Firstly, 62 isolates from 29 timepoints from three in vitro gut models, inoculated with a NAP1/027 strain. Secondly, 122 isolates from 44 patients (2–8 samples/patient) with mostly recurrent/on-going symptomatic NAP-1/027 C. difficile infection. Reference-based mapping was used to identify single nucleotide variants (SNVs).Across three gut model inductions, two with antibiotic treatment, total 137 days, only two new SNVs became established. Pre-existing minority SNVs became dominant in two models. Several SNVs were detected, only present in the minority of colonies at one/two timepoints. The median (inter-quartile range) [range] time between patients’ first and last samples was 60 (29.5–118.5) [0–561] days. Within-patient C. difficile evolution was 0.45 SNVs/called genome/year (95%CI 0.00–1.28) and within-host diversity was 0.28 SNVs/called genome (0.05–0.53). 26/28 gut model and patient SNVs were non-synonymous, affecting a range of gene targets.The consistency of whole genome sequencing data from gut model C. difficile isolates, and the high stability of genomic sequences in isolates from patients, supports the use of whole genome sequencing in detailed transmission investigations.Peer reviewe

Evidence for Planet-induced Chromospheric Activity on HD 179949

We have detected the synchronous enhancement of Ca II H & K emission with the short-period planetary orbit in HD 179949. High-resolution spectra taken on three observing runs extending more than a year show the enhancement coincides with phi ~ 0 (the sub-planetary point) of the 3.093-day orbit with the effect persisting for more than 100 orbits. The synchronous enhancement is consistent with planet-induced chromospheric heating by magnetic rather than tidal interaction. Something which can only be confirmed by further observations. Independent observations are needed to determine whether the stellar rotation is sychronous with the planet's orbit. Of the five 51 Peg-type systems monitored, HD 179949 shows the greatest chromospheric H & K activity. Three others show significant nightly variations but the lack of any phase coherence prevents us saying whether the activity is induced by the planet. Our two standards, tau Ceti and the Sun, show no such nightly variations.Comment: 10 pages, 6 figures. Submitted to Ap