Genericity of Cosmic Strings Formation in SUSY GUTs

The idea of GUT implies that the universe went through a series of phase transitions during which topological defects are expected to form. We investigate here the genericity of cosmic strings formation in realistic SUSY GUTs models. We conclude that all acceptable symmetry breaking schemes produce cosmic strings after the last inflationary phase. Generically, as they form at the end of inflation, they have a mass of order of the GUT scale. Since cosmological data coming from CMB measurements do not show evidence for such strings, they constrain GUT scale physics.Comment: 4 pages, talk at the XXXIX Rencontres de Moriond (La Thuile, March 2004), to appear in the proceeding

Venous thromboembolism risk and prophylaxis prescription in surgical patients at a tertiary hospital in Eastern Cape Province, South Africa

Background. Venous thromboembolism (VTE) is a common complication during and after hospitalisation, and is regarded as the most common cause of preventable death in hospitalised patients worldwide. Despite its importance, there are few data on VTE risk and adherence to prophylaxis prescription guidelines in surgical patients from the South African (SA) public sector, especially from lowresource environments such as Eastern Cape Province.Objectives. To evaluate the risk and prescription of VTE prophylaxis to surgical patients at a tertiary government hospital in the Eastern Cape.Methods. A cross-sectional clinical audit of general surgical inpatients was performed on two dates during July and August 2017. Patients’ VTE risk was calculated by using the Caprini risk assessment model (RAM) and thromboprophylaxis prescription evaluated accordingly.Results. A total of 179 patients were included in the study, of whom 56% were male and 44% female. The average age was 45 (range 18 - 83) years. Of the total number of participants, 33% were elective cases and 67% were emergency admissions. With application of RAM, 77% of patients were at risk of VTE (Caprini score ≥2), with 81% of elective and 74% of emergency patients being at risk. The most prevalent risk factors for VTE were major surgery (34%), age 41 - 60 years (30%), age 61 - 74 years (20%) and sepsis during the previous month (27%). A contraindication to chemoprophylaxis was recorded in 30% of patients, with the most prevalent being renal dysfunction (40%), peptic ulcer disease (34%), active bleeding (17%), liver dysfunction (17%), coagulopathy (6%) and recent cerebral haemorrhage (6%). With regard to VTE risk profile and contraindications to chemoprophylaxis, the correct thromboprophylactic treatment was prescribed to 26% of at-risk patients, with 21% of elective and 27% of emergency admission patients receiving the correct therapy.Conclusions. Despite a high proportion of patients being at risk of VTE, the rate of adequate thromboprophylaxis prescription for surgical inpatients at Frere Hospital, East London, SA is very low. Increased availability of mechanical prophylaxis, as well as interventions to improve the rate of adequate prophylaxis prescription, needs to be evaluated for feasibility and effect in this hospital and other SA public hospitals

Scattering of cosmic strings by black holes: loop formation

We study the deformation of a long cosmic string by a nearby rotating black hole. We examine whether the deformation of a cosmic string, induced by the gravitational field of a Kerr black hole, may lead to the formation of a loop of cosmic string. The segment of the string which enters the ergosphere of a rotating black hole gets deformed and, if it is sufficiently twisted, it can self-intersect chopping off a loop of cosmic string. We find that the formation of a loop, via this mechanism, is a rare event. It will only arise in a small region of the collision phase space, which depends on the string velocity, the impact parameter and the black hole angular momentum. We conclude that generically, the cosmic string is simply scattered or captured by the rotating black hole.Comment: 11 pages, 2 figures, RevTe

D-term inflation in non-minimal supergravity

D-term inflation is one of the most interesting and versatile models of inflation. It is possible to implement naturally D-term inflation within high energy physics, as for example SUSY GUTs, SUGRA, or string theories. D-term inflation avoids the $\eta$-problem, while in its standard form it always ends with the formation of cosmic strings. Given the recent three-year WMAP data on the cosmic microwave background temperature anisotropies, we examine whether D-term inflation can be successfully implemented in non-minimal supergravity theories. We show that for all our choices of K\"ahler potential, there exists a parameter space for which the predictions of D-term inflation are in agreement with the measurements. The cosmic string contribution on the measured temperature anisotropies is always dominant, unless the superpotential coupling constant is fine tuned; a result already obtained for D-term inflation within minimal supergravity. In conclusion, cosmic strings and their r\^ole in the angular power spectrum cannot be easily hidden by just considering a non-flat K\"ahler geometry.Comment: 29 pages, 9 figures; minor changes to match publihed versio

The interplay between high energy physics and cosmology: an example

Cosmology and high energy physics are two closely connected areas. In this lecture I present an example of their rich interplay.Comment: Invited talk at the DPU workshop: The density fluctuations in the Universe: Beyond the inflationary paradigm (Dimokritos, Athens 2004) (see http://physics.ntua.gr/dpu/). 8 two column page

Production of topological defects at the end of inflation

Hybrid inflation within supersymmetric grand unified theories, as well as inflation through brane collisions within braneworld cosmological models, lead to the formation of one-dimensional defects. Observational data, mainly from the cosmic microwave background temperature anisotropies but also from the gravitational wave background, impose constraints on the free parameters of the models. I review these inflationary models and discuss the constraints from the currently available data.Comment: 9 pages, Invited talk in the Conference "Challenges in Particle Astrophysics" -- 6th Rencontres du Vietnam, Hanoi (Vietnam) 6-12 Aug. 200

Venous thromboembolism risk and prophylaxis prescription in surgical patients at a tertiary hospital in Eastern Cape Province, South Africa

Background. Venous thromboembolism (VTE) is a common complication during and after hospitalisation, and is regarded as the most common cause of preventable death in hospitalised patients worldwide. Despite its importance, there are few data on VTE risk and adherence to prophylaxis prescription guidelines in surgical patients from the South African (SA) public sector, especially from low-resource environments such as Eastern Cape Province.Objectives. To evaluate the risk and prescription of VTE prophylaxis to surgical patients at a tertiary government hospital in the Eastern Cape.Methods. A cross-sectional clinical audit of general surgical inpatients was performed on two dates during July and August 2017. Patients’ VTE risk was calculated by using the Caprini risk assessment model (RAM) and thromboprophylaxis prescription evaluated accordingly.Results. A total of 179 patients were included in the study, of whom 56% were male and 44% female. The average age was 45 (range 18 - 83) years. Of the total number of participants, 33% were elective cases and 67% were emergency admissions. With application of RAM, 77% of patients were at risk of VTE (Caprini score ≥2), with 81% of elective and 74% of emergency patients being at risk. The most prevalent risk factors for VTE were major surgery (34%), age 41 - 60 years (30%), age 61 - 74 years (20%) and sepsis during the previous month (27%). A contraindication to chemoprophylaxis was recorded in 30% of patients, with the most prevalent being renal dysfunction (40%), peptic ulcer disease (34%), active bleeding (17%), liver dysfunction (17%), coagulopathy (6%) and recent cerebral haemorrhage (6%). With regard to VTE risk profile and contraindications to chemoprophylaxis, the correct thromboprophylactic treatment was prescribed to 26% of at-risk patients, with 21% of elective and 27% of emergency admission patients receiving the correct therapy.Conclusions. Despite a high proportion of patients being at risk of VTE, the rate of adequate thromboprophylaxis prescription for surgical inpatients at Frere Hospital, East London, SA is very low. Increased availability of mechanical prophylaxis, as well as interventions to improve the rate of adequate prophylaxis prescription, needs to be evaluated for feasibility and effect in this hospital and other SA public hospitals

La gestion sociale urbaine dans les pays en développement : rapport de fin de recherche mai 1993

Les réflexions proposées ici représentent une étape dans une recherche menée par une équipe du laboratoire TMU sur le thème de "la gestion sociale urbaine dans les pays en développement" ; elle privilégie dans le champ global de la gestion urbaine la dimension sociale, en la considérant comme mécanisme de régulation des rapports sociaux urbains, et comme système de contrôle des populations urbaines. La recherche s'appuie sur l'observation et l'analyse des pratiques des gestionnaires et de celles des citadins, à partir de deux entrées : la régularisation foncière, technique de gestion du sol urbain, mais aussi mode de régulation des rapports sociaux en ville, et la gestion urbaine partagée des services urbains. C'est autour de ces deux axes que s'est tenue une journée de réflexion en mai 1992, qui a permis de mieux cerner les possibilitiés et les limites de la gestion sociale urbaine à son niveau le plus approprié, celui des collectivités territoriales locales. (Résumé d'auteur