1,363 research outputs found
Gravitino fields in Schwarzschild black hole spacetimes
The analysis of gravitino fields in curved spacetimes is usually carried out
using the Newman-Penrose formalism. In this paper we consider a more direct
approach with eigenspinor-vectors on spheres, to separate out the angular parts
of the fields in a Schwarzschild background. The radial equations of the
corresponding gauge invariant variable obtained are shown to be the same as in
the Newman-Penrose formalism. These equations are then applied to the
evaluation of the quasinormal mode frequencies, as well as the absorption
probabilities of the gravitino field scattering in this background.Comment: 21 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1006.3327 by other author
Career Transitions in Sport
The transition out of sport prompts an identity change for the athlete. When putting an end to their sporting career, an athlete loses an important part of themselves, particularly if they have been training and competing in their sport for much of their life. This may apply to the youth athlete who will not compete in college, the collegiate athlete who will not compete professionally, and the professional athlete who is retiring. Because athletes spend a great deal of time training and devoting themselves to their sport, they may not have time for exploration of activities or careers outside of sport. This leads to identity foreclosure and a strong athletic identity, which has been associated with difficulty adjusting following sport career termination (Murphy, Petitpas, & Brewer, 1996)
Career Transitions in Sport
The transition out of sport prompts an identity change for the athlete. When putting an end to their sporting career, an athlete loses an important part of themselves, particularly if they have been training and competing in their sport for much of their life. This may apply to the youth athlete who will not compete in college, the collegiate athlete who will not compete professionally, and the professional athlete who is retiring. Because athletes spend a great deal of time training and devoting themselves to their sport, they may not have time for exploration of activities or careers outside of sport. This leads to identity foreclosure and a strong athletic identity, which has been associated with difficulty adjusting following sport career termination (Murphy, Petitpas, & Brewer, 1996)
Studies on the Induction of Antigen-Specific Antibody in Anti-CD40 Cultured Human B Lymphocytes
Costimulatory signals provided by T cells are required for B cells to produce specific antibody to T-dependent antigen. We have investigated the suitability of using the CD40 culture system for the proliferation and differentiation of Ag-specific human B cells using cytomegalovirus (CMV) or tetanus toxoid (TT) as antigen. We modified the CD40 culture system (CD32- transfected L cells, anti-CD40, and IL-4) by applying a sequential cytokine stimulation and compared total B-cell cultures with antigen-specific B cells preselected by panning. The detection of specific antibody became possible when antigen-selected B cells were cultured for 7 days in the CD40 system to induce clonal expansion, followed by the addition of IL-2 and IL10 for an additional 7 days to induce plasma-cell differentiation. We conclude that our intial inability to detect specific antibody in the CD40 system is due to overgrowth of nonspecific B cell clones and that selection of antigen-specific B cells by panning overcomes this problem. Induction of antigen-specific antibody production was found to be optimal when the initial
contact with antigen during panning was limited to between 1 to 24 hours
Vitamin C Supplementation in Healthy Individuals Leads to Shifts of Bacterial Populations in the Gut - A Pilot Study
Gut microbes are crucial to human health, but microbial composition is often disturbed in a number of human diseases. Accumulating evidence points to nutritional modulation of the gut microbiota as a potentially beneficial therapeutic strategy. Vitamin C (ascorbic acid) may be of particular interest as it has known antioxidant and anti-inflammatory properties. In this study, we investigated whether supplementation with high-dose vitamin C may favourably affect the composition of the gut microbiota. In this pilot study, healthy human participants received 1000 mg vitamin C supplementation daily for two weeks. Gut microbiota composition was analysed before and after intervention by performing faecal 16S rRNA gene sequencing. In total, 14 healthy participants were included. Daily supplementation of high-dose vitamin C led to an increase in the relative abundances of Lachnospiraceae (p < 0.05), whereas decreases were observed for Bacteroidetes (p < 0.01), Enterococci (p < 0.01) and Gemmiger formicilis (p < 0.05). In addition, trends for bacterial shifts were observed for Blautia (increase) and Streptococcus thermophilus (decrease). High-dose vitamin C supplementation for two weeks shows microbiota-modulating effects in healthy individuals, with several beneficial shifts of bacterial populations. This may be relevant as these bacteria have anti-inflammatory properties and strongly associate with gut health
Nutritional and ecological perspectives of the interrelationships between diet and the gut microbiome in multiple sclerosis:Insights from marmosets
Studies in experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis, have shown potential links between diet components, microbiome composition, and modulation of immune responses. In this review, we reanalyze and discuss findings in an outbred marmoset EAE model in which a yogurt-based dietary supplement decreased disease frequency and severity. We show that although diet has detectable effects on the fecal microbiome, microbiome changes are more strongly associated with the EAE development. Using an ecological framework, we further show that the dominant factors influencing the gut microbiota were marmoset sibling pair and experimental time point. These findings emphasize challenges in assigning cause-and-effect relationships in studies of diet-microbiome-host interactions and differentiating the diet effects from other environmental, stochastic, and host-related factors. We advocate for animal experiments to be designed to allow causal inferences of the microbiota's role in pathology while considering the complex ecological processes that shape microbial communities
Onderzoek naar risicoselectie met de basisset kwaliteitsindicatoren ziekenhuizen: op weg naar verantwoorde keuzes
Onderzoek naar risicoselectie met de basisset kwaliteitsindicatoren ziekenhuizen: op weg naar verantwoorde keuzes
An African Approach for Risk Reduction of Soil Contaminated by Obsolete Pesticides
Since the 1950s, large amounts of pesticides were shipped to Africa for locust control, but did not arrive at the proper place or proper time thereby rendering them obsolete. Stockpiles of these pesticides have created a serious problem and The Africa Stockpiles Programme (ASP), launched by FAO, is designed to rid Africa of stockpiles and to dispose of them in an environmentally sound manner (ASP, 2009). From July to August 2007, an investigation mission was organized by FAO pesticide management programme, in collaboration with Wageningen University and Research Centre and the relevant national counterpart institutions of the Ministries of Agriculture and the Ministries of Environment in Mali and Mauritania. During the investigation, three sites in Mali and three sites in Mauretania were visited in the summer of 2007. High concentrations of pesticides were found in soils on the stockpiles. From a riskbased point of view, contaminations are only a risk if they are or may become available. Based on the results obtained and results of analysis of the samples taken, risk reduction proposals have been developed. All proposals are based on stimulation of the possibilities of biological degradation of the pesticides in combination with isolation and preventing rain water from transporting the pesticides. The results were discussed in May 2008 and the first implementation was started in Molodo (Mali) in July 2008
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