Human Resource Practices and Organizational Commitment: A Deeper Examination

This paper examines newer conceptualizations of HRM practices in the HR-Performance Relationship as well as newer conceptualizations of commitment. Juxtaposing these categories of HR practices and types of commitment provides a clearer theoretical rational for at least some ways that HR practices can influence organizational performance, be that positive or negative. Implications for research are then discussed

Defensive insect symbiont leads to cascading extinctions and community collapse

This is the final version of the article. Available from Wiley via the DOI in this record.Animals often engage in mutualistic associations with microorganisms that protect them from predation, parasitism or pathogen infection. Studies of these interactions in insects have mostly focussed on the direct effects of symbiont infection on natural enemies without studying community-wide effects. Here, we explore the effect of a defensive symbiont on population dynamics and species extinctions in an experimental community composed of three aphid species and their associated specialist parasitoids. We found that introducing a bacterial symbiont with a protective (but not a non-protective) phenotype into one aphid species led to it being able to escape from its natural enemy and increase in density. This changed the relative density of the three aphid species which resulted in the extinction of the two other parasitoid species. Our results show that defensive symbionts can cause extinction cascades in experimental communities and so may play a significant role in the stability of consumer-herbivore communities in the field.The authors thank two anonymous reviewers for their helpful comments. This project was funded by the British Ecological Society (BES research grant #4682/5720 to EF), and by the Natural Environment Research Council (NERC grant #NE/K005650/1 to FJFvV). EF was funded by Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme, FP7-PEOPLE-2012-IEF #329648

Mesenchymal Stem Cell-Derived Extracellular Vesicles Reduce Disease Severity and Immune Responses in Inflammatory Arthritis

Abstract Background Novel biological therapies have revolutionised the management of Rheumatoid Arthritis (RA) but no cure currently exists. Mesenchymal stem cells (MSCs) immunomodulate inflammatory responses through paracrine signalling via growth factors, cytokines, chemokines and extracellular vesicles (EVs) in the cell secretome; however, MSCs are still not available in the clinic. We evaluated the therapeutic potential of MSCs-derived EVs in an antigen-induced model of arthritis (AIA). Methods EVs isolated from MSCs in normal (21% O 2 , 5% CO 2 ) or hypoxic (2% O 2 , 5% CO 2 ) culture or from MSCs pre-conditioned with a pro-inflammatory cytokine cocktail were applied into the AIA model. Disease pathology was assessed 3 days post arthritis induction through histopathological analysis of knee joints. Spleens and lymph nodes were collected and assessed for T cell polarisation within the immune response to AIA. Activated naïve CD4+ T cells from spleens of healthy mice were cultured with EVs or MSCs to assess deactivation capabilities. Results All EV treatments significantly reduced knee-joint swelling and histopathological signs of AIA with enhanced responses to normoxic and pro-inflammatory primed EVs. Polarisation of T cells towards CD4+ helper cells expressing IL17a (Th17) was reduced when EV treatments from MSCs cultured in hypoxia or pro-inflammatory priming conditions were applied. Conclusions Hypoxically cultured EVs present a priming methodology that is as effective in reducing swelling, IL-17a expression, Th17 polarisation and T cell proliferation as pro-inflammatory priming. EVs present an effective novel technology for cell-free therapeutic translation in treating inflammatory arthritis and autoimmune disorders such as RA

ROTSE All Sky Surveys for Variable Stars I: Test Fields

The ROTSE-I experiment has generated CCD photometry for the entire Northern sky in two epochs nightly since March 1998. These sky patrol data are a powerful resource for studies of astrophysical transients. As a demonstration project, we present first results of a search for periodic variable stars derived from ROTSE-I observations. Variable identification, period determination, and type classification are conducted via automatic algorithms. In a set of nine ROTSE-I sky patrol fields covering about 2000 square degrees we identify 1781 periodic variable stars with mean magnitudes between m_v=10.0 and m_v=15.5. About 90% of these objects are newly identified as variable. Examples of many familiar types are presented. All classifications for this study have been manually confirmed. The selection criteria for this analysis have been conservatively defined, and are known to be biased against some variable classes. This preliminary study includes only 5.6% of the total ROTSE-I sky coverage, suggesting that the full ROTSE-I variable catalog will include more than 32,000 periodic variable stars.Comment: Accepted for publication in AJ 4/00. LaTeX manuscript. (28 pages, 11 postscript figures and 1 gif

The ROTSE-III Robotic Telescope System

The observation of a prompt optical flash from GRB990123 convincingly demonstrated the value of autonomous robotic telescope systems. Pursuing a program of rapid follow-up observations of gamma-ray bursts, the Robotic Optical Transient Search Experiment (ROTSE) has developed a next-generation instrument, ROTSE-III, that will continue the search for fast optical transients. The entire system was designed as an economical robotic facility to be installed at remote sites throughout the world. There are seven major system components: optics, optical tube assembly, CCD camera, telescope mount, enclosure, environmental sensing & protection and data acquisition. Each is described in turn in the hope that the techniques developed here will be useful in similar contexts elsewhere.Comment: 19 pages, including 4 figures. To be published in PASP in January, 2003. PASP Number IP02-11

Mid-infrared resolution of a 3 AU-radius debris disk around Zeta Leporis

We present subarcsecond-resolution mid-infrared images of the debris disk surrounding the 230 Myr- old A star Zeta Lep. Our data obtained with T-ReCS at Gemini South show the source to be unresolved at 10.4 microns but clearly extended at 18.3 microns. Quadratic subtraction of the PSF profile from that of Zeta Lep implies a characteristic radius for the dust disk of 3 AU, which is comparable in size to our solar system's asteroid belt. Simple models suggest that the 18 micron flux is well approximated by two contiguous annuli of mid-infrared-emitting dust from 2-4 and 4-8 AU with a 3:1 flux ratio for the annuli, respectively. We consider two scenarios for the collisions that must be resupplying the dust population: (1) continuous "steady state" grinding of planetesimals, and (2) an isolated cataclysmic collision. We determine that radiation pressure and subsequent collisions are the dominant determinants of the disk morphology in either case, and that Poynting-Robertson drag is comparatively insignificant.Comment: 4 pages, 1 figure, accepted for publication in ApJ Letter

The development, validation, and user evaluation of foodbook24: A web-based dietary assessment tool developed for the Irish adult population

Background: The application of technology in the area of dietary assessment has resulted in the development of an array of tools, which are often specifically designed for a particular country or region. Objective: The aim of this study was to describe the development, validation, and user evaluation of a Web-based dietary assessment tool “Foodbook24.” Methods: Foodbook24 is a Web-based, dietary assessment tool consisting of a 24-hour dietary recall (24HDR) and food frequency questionnaire (FFQ) alongside supplementary questionnaires. Validity of the 24HDR component was assessed by 40 participants, who completed 3 nonconsecutive, self-administered 24HDR using Foodbook24 and a 4-day semi-weighed food diary at separate time points. Participants also provided fasted blood samples and 24-hour urine collections for the identification of biomarkers of nutrient and food group intake during each recording period. Statistical analyses on the nutrient and food group intake data derived from each method were performed in SPSS version 20.0 (SPSS Inc). Mean nutrient intakes (and standard deviations) recorded using each method of dietary assessment were calculated. Spearman and Pearson correlations, Wilcoxon Signed Rank and Paired t test were used to investigate the agreement and differences between the nutritional output from Foodbook24 (test method) and the 4-day semi-weighed food diary (reference method). Urinary and plasma biomarkers of nutrient intake were used as an objective validation of Foodbook24. To investigate the user acceptability of Foodbook24, participants from different studies involved with Foodbook24 were asked to complete an evaluation questionnaire. Results: For nutrient intake, correlations between the dietary assessment methods were acceptable to very good in strength and statistically significant (range r=.32 to .75). There were some significant differences between reported mean intakes of micronutrients recorded by both methods; however, with the exception of protein (P=.03), there were no significant differences in the reporting of energy or macronutrient intake. Of the 19 food groups investigated in this analysis, there were significant differences between 6 food groups reported by both methods. Spearman correlations for biomarkers of nutrient and food group intake and reported intake were similar for both methods. A total of 118 participants evaluated the acceptability of Foodbook24. The tool was well-received and the majority, 67.8% (80/118), opted for Foodbook24 as the preferred method for future dietary intake assessment when compared against a traditional interviewer led recall and semi-weighed food diary. Conclusions: The results of this study demonstrate the validity and user acceptability of Foodbook24. The results also highlight the potential of Foodbook24, a Web-based dietary assessment method, and present a viable alternative to nutritional surveillance in Ireland