715 research outputs found

    IIA/IIB Supergravity and Ten-forms

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    We perform a careful investigation of which p-form fields can be introduced consistently with the supersymmetry algebra of IIA and/or IIB ten-dimensional supergravity. In particular the ten-forms, also known as "top-forms", require a careful analysis since in this case, as we will show, closure of the supersymmetry algebra at the linear level does not imply closure at the non-linear level. Consequently, some of the (IIA and IIB) ten-form potentials introduced in earlier work of some of us are discarded. At the same time we show that new ten-form potentials, consistent with the full non-linear supersymmetry algebra can be introduced. We give a superspace explanation of our work. All of our results are precisely in line with the predictions of the E(11) algebra.Comment: 17 page

    Maximal supergravity in D=10: forms, Borcherds algebras and superspace cohomology

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    We give a very simple derivation of the forms of N=2,D=10N=2,D=10 supergravity from supersymmetry and SL(2,\bbR) (for IIB). Using superspace cohomology we show that, if the Bianchi identities for the physical fields are satisfied, the (consistent) Bianchi identities for all of the higher-rank forms must be identically satisfied, and that there are no possible gauge-trivial Bianchi identities (dF=0dF=0) except for exact eleven-forms. We also show that the degrees of the forms can be extended beyond the spacetime limit, and that the representations they fall into agree with those predicted from Borcherds algebras. In IIA there are even-rank RR forms, including a non-zero twelve-form, while in IIB there are non-trivial Bianchi identities for thirteen-forms even though these forms are identically zero in supergravity. It is speculated that these higher-rank forms could be non-zero when higher-order string corrections are included.Comment: 15 pages. Published version. Some clarification of the tex

    Protective effects of curcumin against gamma radiation-induced ileal mucosal damage

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    The major objective of this study was to test curcumin as a potential radioprotectant for the ileum goblet cells of the rat. Wistar albino rats were used in the study. Group A was the control group and group B was the single dose radiation group. Group C was the two dose radiation group (4 days interval). The rats in groups D and E were given a daily dose of 100 mg/kg of curcumin for 14 and 18 days, respectively. During the curcumin administration period, the rats in group D were exposed to abdominal area gamma (γ)-ray dose of 5 Gy on the 10th day and group E was exposed to same dose radiation on the 10th and 14th day. Irradiation and treatment groups were decapitated on the 4th day after exposure to single or two-dose irradiation and ileum tissues were removed for light and electron microscopic investigation. Single or two dose 5 Gy γ-irradiation caused a marked intestinal mucosal injury in rats on the 4th day. Radiation produced increases in the number of goblet cells. Curcumin appears to have protective effects against radiation-induced damage, suggesting that clinical transfer is feasible

    Impaired psychological recovery in the elderly after the Niigata-Chuetsu Earthquake in Japan:a population-based study

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    BACKGROUND: An earthquake measuring 6.8 on the Richter scale struck the Niigata-Chuetsu region of Japan at 5.56 P.M. on the 23rd of October, 2004. The earthquake was followed by sustained occurrence of numerous aftershocks, which delayed reconstruction of community lifelines. Even one year after the earthquake, 9,160 people were living in temporary housing. Such a devastating earthquake and life after the earthquake in an unfamiliar environment should cause psychological distress, especially among the elderly. METHODS: Psychological distress was measured using the 12-item General Health Questionnaire (GHQ-12) in 2,083 subjects (69% response rate) who were living in transient housing five months after the earthquake. GHQ-12 was scored using the original method, Likert scoring and corrected method. The subjects were asked to assess their psychological status before the earthquake, their psychological status at the most stressful time after the earthquake and their psychological status at five months after the earthquake. Exploratory and confirmatory factor analysis was used to reveal the factor structure of GHQ12. Multiple regression analysis was performed to analyze the relationship between various background factors and GHQ-12 score and its subscale. RESULTS: GHQ-12 scores were significantly elevated at the most stressful time and they were significantly high even at five months after the earthquake. Factor analysis revealed that a model consisting of two factors (social dysfunction and dysphoria) using corrected GHQ scoring showed a high level of goodness-of-fit. Multiple regression analysis revealed that age of subjects affected GHQ-12 scores. GHQ-12 score as well as its factor 'social dysfunction' scale were increased with increasing age of subjects at five months after the earthquake. CONCLUSION: Impaired psychological recovery was observed even at five months after the Niigata-Chuetsu Earthquake in the elderly. The elderly were more affected by matters relating to coping with daily problems

    Survey of patient satisfaction with the Breastfeeding Education and Support Services of The Royal Women's Hospital, Melbourne

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    <p>Abstract</p> <p>Background</p> <p>The Breastfeeding Education and Support Services (BESS) is a unit of The Royal Women's Hospital in Melbourne, Australia, staffed by International Board Certified Lactation Consultants (IBCLCs), providing day/short-stay and an outpatient clinic for mothers and infants with breastfeeding problems. It is important to measure women's experience of visiting the service as part of quality assurance. The aim of this project was to conduct an anonymous postal survey of clients' satisfaction with BESS.</p> <p>Methods</p> <p>An anonymous survey was posted on 16 November 2005 and again on 31 January 2006, to all women who had attended BESS in September 2005.</p> <p>Results</p> <p>The response rate was 60.5% (78/129). Eighty percent (62/78) of respondents attended day-stay, 33% (26/78) attended short-stay and 15% (12/78) attended the outpatient clinic. The percentage of women who responded "strongly agree" to the statement "Overall, I am satisfied with the services" was 49% (35/72) and 50% (6/12) for those who went to day/short-stay and the outpatient clinic respectively. Overall, 56% of all respondents responded that the quality of BESS was "better than expected". The most common breastfeeding problem reported was difficulty attaching the baby to the breast, followed by nipple damage, low milk supply and painful feeding.</p> <p>Conclusion</p> <p>BESS seems to have provided a satisfactory service to most clients. Most respondents were clearly satisfied with the support given by the IBCLCs and have also responded that the staff were professional and knowledgeable in their field of work.</p

    The role of recombination in the emergence of a complex and dynamic HIV epidemic

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    <p>Abstract</p> <p>Background</p> <p>Inter-subtype recombinants dominate the HIV epidemics in three geographical regions. To better understand the role of HIV recombinants in shaping the current HIV epidemic, we here present the results of a large-scale subtyping analysis of 9435 HIV-1 sequences that involve subtypes A, B, C, G, F and the epidemiologically important recombinants derived from three continents.</p> <p>Results</p> <p>The circulating recombinant form CRF02_AG, common in West Central Africa, appears to result from recombination events that occurred early in the divergence between subtypes A and G, followed by additional recent recombination events that contribute to the breakpoint pattern defining the current recombinant lineage. This finding also corrects a recent claim that G is a recombinant and a descendant of CRF02, which was suggested to be a pure subtype. The BC and BF recombinants in China and South America, respectively, are derived from recent recombination between contemporary parental lineages. Shared breakpoints in South America BF recombinants indicate that the HIV-1 epidemics in Argentina and Brazil are not independent. Therefore, the contemporary HIV-1 epidemic has recombinant lineages of both ancient and more recent origins.</p> <p>Conclusions</p> <p>Taken together, we show that these recombinant lineages, which are highly prevalent in the current HIV epidemic, are a mixture of ancient and recent recombination. The HIV pandemic is moving towards having increasing complexity and higher prevalence of recombinant forms, sometimes existing as "families" of related forms. We find that the classification of some CRF designations need to be revised as a consequence of (1) an estimated > 5% error in the original subtype assignments deposited in the Los Alamos sequence database; (2) an increasing number of CRFs are defined while they do not readily fit into groupings for molecular epidemiology and vaccine design; and (3) a dynamic HIV epidemic context.</p

    Formation of Supermassive Black Holes

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    Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.Comment: To appear in The Astronomy and Astrophysics Review. The final publication is available at http://www.springerlink.co
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