An excess of goodness? Volunteering among Aid professionals in Cambodia

This paper explores the meaning of volunteering among professional aid workers. While they experience disenchantment in their daytime work, volunteering provides them with benefits lacking in their paid jobs. At the same time, a compensatory model does not capture the complex dimensions of this relationship. One motive behind their professional work – bringing about positive change for others - is also the driving force behind their voluntary practices. Such excess of doing good may be indicative of their overall commitment. If aid workers make sense of their actions within a framework of alienated labour, rendering their waged aid work as a commodity, volunteering emerges as a remedial response. At the same time, their paid and unpaid work is animated by the impulse of giving. Such co-existence implies that gifts and commodities are not mutually exclusive; or indeed that both can be understood, following Parry (1986), as emerging from a highly developed capitalist system

Unpacking distinction within mobility : social prestige and international students

Author thanks the Social Sciences and Humanities Research Council of Canada (SSHRC) for their funding on this projecThis paper investigates the complex ways in which young people engage in social distinction within international mobility. The study offers novel conceptual and empirical insights by examining how distinction and social advantage is reproduced through short‐term student mobility from the Global North to the Global South. In doing so, it elucidates the iterative process of distinction‐making within mobility and argues that young mobile people negotiate a tension between different forms of distinction. Specifically, it unpacks and conceptualises distinction into dual categories—collective and individual—and suggests that students alternate and waver between these categories in order to both validate and elevate their position within a mobility hierarchy. The paper also considers how particular places are viewed as more distinctive and affording greater gains in cultural and symbolic capital. It concludes with future interrogations and ways forward for research on international mobility and distinction.PostprintPeer reviewe

A glimpse on Staphylococcus aureus translation machinery and its control

© 2016, Pleiades Publishing, Inc.Staphylococcus aureus is a major opportunistic and versatile pathogen. Because the bacteria rapidly evolve multi-resistances towards antibiotics, there is an urgent need to find novel targets and alternative strategies to cure bacterial infections. Here, we provide a brief overview on the knowledge acquired on S. aureus ribosomes, which is one of the major antibiotic targets. We will show that subtle differences exist between the translation at the initiation step of Gram-negative and Gram-positive bacteria although their ribosomes display a remarkable degree of resemblance. In addition, we will illustrate using specific examples the diversity of mechanisms controlling translation initiation in S. aureus that contribute to shape the expression of the virulence factors in a temporal and dynamic manner

Claims to a nation, dressing the part and other boundary making strategies by skilled migrants in response to ethnic categorization

This article is about self-defined social identities, other people's perceptions of us and the potentially conflictual relationship between these two. Building on a Barthian focus on group boundaries, the article takes the interplay between external categorizations and internal group definitions as its point of departure to examine how individuals negotiate the boundaries of their social identities. Based on a case study of skilled migrants with racialized ethnicities in Finland, I look at how they express their self-defined identity as well-to-do, skilled professionals in the face of contradicting categorizations of them as unskilled , lower-class migrant subjects. I identify two types of complementary approaches employed by the skilled migrants in boundary making strategies to their identity negotiations: those de-emphasizing ethnicity (or its importance), and those emphasizing class status. These approaches are two sides of the same coin; coming from different perspectives, they both aim at a more positively viewed identity, and for individuals to be seen as well-to-do, educated, working professionals, rather than as ethnic migrant subjects. As such, the article also highlights the interconnection of class and ethnicity for the social identities of skilled migrants in Finland.This article is about self-defined social identities, other people’s perceptions of us and the potentially conflictual relationship between these two. Building on a Barthian focus on group boundaries, the article takes the interplay between external categorizations and internal group definitions as its point of departure to examine how individuals negotiate the boundaries of their social identities. Based on a case study of skilled migrants with racialized ethnicities in Finland, I look at how they express their self-defined identity as well-to-do, skilled professionals in the face of contradicting categorizations of them as un-skilled, lower-class migrant subjects. I identify two types of complementary approaches employed by the skilled migrants in boundary making strategies to their identity negotiations: those de-emphasizing ethnicity (or its importance), and those emphasizing class status. These approaches are two sides of the same coin; coming from different perspectives, they both aim at a more positively viewed identity, and for individuals to be seen as well-to-do, educated, working professionals, rather than as ethnic migrant subjects. As such, the article also highlights the interconnection of class and ethnicity for the social identities of skilled migrants in Finland.Peer reviewe

Nucleic Acids Res

Cells adapt to environmental changes by efficiently adjusting gene expression programs. Staphylococcus aureus, an opportunistic pathogenic bacterium, switches between defensive and offensive modes in response to quorum sensing signal. We identified and studied the structural characteristics and dynamic properties of the core regulatory circuit governing this switch by deterministic and stochastic computational methods, as well as experimentally. This module, termed here Double Selector Switch (DSS), comprises the RNA regulator RNAIII and the transcription factor Rot, defining a double-layered switch involving both transcriptional and post-transcriptional regulations. It coordinates the inverse expression of two sets of target genes, immuno-modulators and exotoxins, expressed during the defensive and offensive modes, respectively. Our computational and experimental analyses show that the DSS guarantees fine-tuned coordination of the inverse expression of its two gene sets, tight regulation, and filtering of noisy signals. We also identified variants of this circuit in other bacterial systems, suggesting it is used as a molecular switch in various cellular contexts and offering its use as a template for an effective switching device in synthetic biology studies

PLoS Biol

Regulation of translation initiation is well appropriate to adapt cell growth in response to stress and environmental changes. Many bacterial mRNAs adopt structures in their 5' untranslated regions that modulate the accessibility of the 30S ribosomal subunit. Structured mRNAs interact with the 30S in a two-step process where the docking of a folded mRNA precedes an accommodation step. Here, we used a combination of experimental approaches in vitro (kinetic of mRNA unfolding and binding experiments to analyze mRNA-protein or mRNA-ribosome complexes, toeprinting assays to follow the formation of ribosomal initiation complexes) and in vivo (genetic) to monitor the action of ribosomal protein S1 on the initiation of structured and regulated mRNAs. We demonstrate that r-protein S1 endows the 30S with an RNA chaperone activity that is essential for the docking and the unfolding of structured mRNAs, and for the correct positioning of the initiation codon inside the decoding channel. The first three OB-fold domains of S1 retain all its activities (mRNA and 30S binding, RNA melting activity) on the 30S subunit. S1 is not required for all mRNAs and acts differently on mRNAs according to the signals present at their 5' ends. This work shows that S1 confers to the ribosome dynamic properties to initiate translation of a large set of mRNAs with diverse structural features

Interobserver agreement on definition of the target volume in stereotactic radiotherapy for pancreatic adenocarcinoma using different imaging modalities

PURPOSE The aim of this study was to evaluate interobserver agreement (IOA) on target volume definition for pancreatic cancer (PACA) within the Radiosurgery and Stereotactic Radiotherapy Working Group of the German Society of Radiation Oncology (DEGRO) and to identify the influence of imaging modalities on the definition of the target volumes. METHODS Two cases of locally advanced PACA and one local recurrence were selected from a large SBRT database. Delineation was based on either a planning 4D CT with or without (w/wo) IV contrast, w/wo PET/CT, and w/wo diagnostic MRI. Novel compared to other studies, a combination of four metrics was used to integrate several aspects of target volume segmentation: the Dice coefficient (DSC), the Hausdorff distance (HD), the probabilistic distance (PBD), and the volumetric similarity (VS). RESULTS For all three GTVs, the median DSC was 0.75 (range 0.17-0.95), the median HD 15 (range 3.22-67.11) mm, the median PBD 0.33 (range 0.06-4.86), and the median VS was 0.88 (range 0.31-1). For ITVs and PTVs the results were similar. When comparing the imaging modalities for delineation, the best agreement for the GTV was achieved using PET/CT, and for the ITV and PTV using 4D PET/CT, in treatment position with abdominal compression. CONCLUSION Overall, there was good GTV agreement (DSC). Combined metrics appeared to allow a more valid detection of interobserver variation. For SBRT, either 4D PET/CT or 3D PET/CT in treatment position with abdominal compression leads to better agreement and should be considered as a very useful imaging modality for the definition of treatment volumes in pancreatic SBRT. Contouring does not appear to be the weakest link in the treatment planning chain of SBRT for PACA

The N-Terminal Region of the PA Subunit of the RNA Polymerase of Influenza A/HongKong/156/97 (H5N1) Influences Promoter Binding

BACKGROUND: The RNA polymerase of influenza virus is a heterotrimeric complex of PB1, PB2 and PA subunits which cooperate in the transcription and replication of the viral genome. Previous research has shown that the N-terminal region of the PA subunit of influenza A/WSN/33 (H1N1) virus is involved in promoter binding. METHODOLOGY/PRINCIPAL FINDINGS: Here we extend our studies of the influenza RNA polymerase to that of influenza strains A/HongKong/156/97 (H5N1) and A/Vietnam/1194/04 (H5N1). Both H5N1 strains, originally isolated from patients in 1997 and 2004, showed significantly higher polymerase activity compared with two classical human strains, A/WSN/33 (H1N1) and A/NT/60/68 (H3N2) in vitro. This increased polymerase activity correlated with enhanced promoter binding. The N-terminal region of the PA subunit was the major determinant of this enhanced promoter activity. CONCLUSIONS/SIGNIFICANCE: Overall we suggest that the N-terminal region of the PA subunit of two recent H5N1 strains can influence promoter binding and we speculate this may be a factor in their virulence

Base Pairing Interaction between 5'- and 3'-UTRs Controls icaR mRNA Translation in Staphylococcus aureus.

The presence of regulatory sequences in the 3' untranslated region (3'-UTR) of eukaryotic mRNAs controlling RNA stability and translation efficiency is widely recognized. In contrast, the relevance of 3'-UTRs in bacterial mRNA functionality has been disregarded. Here, we report evidences showing that around one-third of the mapped mRNAs of the major human pathogen Staphylococcus aureus carry 3'-UTRs longer than 100-nt and thus, potential regulatory functions. We selected the long 3'-UTR of icaR, which codes for the repressor of the main exopolysaccharidic compound of the S. aureus biofilm matrix, to evaluate the role that 3'-UTRs may play in controlling mRNA expression. We showed that base pairing between the 3'-UTR and the Shine-Dalgarno (SD) region of icaR mRNA interferes with the translation initiation complex and generates a double-stranded substrate for RNase III. Deletion or substitution of the motif (UCCCCUG) within icaR 3'-UTR was sufficient to abolish this interaction and resulted in the accumulation of IcaR repressor and inhibition of biofilm development. Our findings provide a singular example of a new potential post-transcriptional regulatory mechanism to modulate bacterial gene expression through the interaction of a 3'-UTR with the 5'-UTR of the same mRNA