6,196 research outputs found

    Development of a triple GEM UV-photon detector operated in pure CF4 for the PHENIX experiment

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    Results obtained with a triple GEM detector operated in pure CF4 with and without a reflective CsI photocathode are presented. The detector operates in a stable mode at gains up to 10^4. A deviation from exponential growth starts to develop when the total charge exceeds ~ 4 10^6 e leading to gain saturation when the total charge is ~ 2 10^7 e and making the structure relatively robust against discharges. No aging effects are observed in the GEM foils after a total accumulated charge of ~ 10 mC/cm^2 at the anode. The ion back-flow current to the reflective photocathode is comparable to the electron current to the anode. However, no significant degradation of the CsI photocathode is observed for a total ion back-flow charge of ~ 7 mC/cm^2.Comment: 14 pages, 11 figures, Submitted to NIM

    Generating Functionals for Harmonic Expectation Values of Paths with Fixed End Points. Feynman Diagrams for Nonpolynomial Interactions

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    We introduce a general class of generating functionals for the calculation of quantum-mechanical expectation values of arbitrary functionals of fluctuating paths with fixed end points in configuration or momentum space. The generating functionals are calculated explicitly for harmonic oscillators with time-dependent frequency, and used to derive a smearing formulas for correlation functions of polynomial and nonpolynomials functions of time-dependent positions and momenta. These formulas summarize the effect of thermal and quantum fluctuations, and serve to derive generalized Wick rules and Feynman diagrams for perturbation expansions of nonpolynomial interactions.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/28

    What are children's trusts? Early findings from a national survey

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    <i>Background:</i> The Children Act 2004 and National Service Framework for Children, Young People and Maternity Services require fuller integration of health, education and social services for children and young people in England and Wales. The UK government supported the establishment of 35 experimental children's trust pathfinders (henceforth called children's trusts) in England. <i>Methods:</i> A questionnaire was completed by managers in all 35 children's trusts a year after their start. Children's trust documents were examined. Census and performance indicators were compared between children's trust areas and the rest of England. <i>Results</i> Children's trust areas had demographic and social characteristics typical of England. All children's trusts aimed to improve health, education and social services by greater managerial and service integration. All had boards representing the three sectors; other agencies’ representation varied. Two-thirds of children's trusts had moved towards pooling budgets in at least some service areas. At this stage in their development, some had prioritized joint procurement or provision of services, with formal managerial structures, while others favoured an informal strategic planning, co-ordination and information sharing approach. The commonest priorities for services development were for disabled children (16 children's trusts), followed by early intervention (11) and mental health services (8). <i>Conclusions:</i> The diverse strategies adopted by these 35 children's trusts during their first year is due to their own characteristics and to the way government strategy developed during this period. Whilst some prioritized organizational development, joint financing and commissioning, and information sharing, others laid more emphasis on mechanisms for bringing front-line professionals closer together. Their experiences are of value to others deciding how best to integrate children's services

    Dynamique structurale des îlots de forêt claire à Anogeissus leiocarpa (DC.) Guill. et Perr. dans le Sud-Ouest du Burkina Faso

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    Les forêts claires résultent de la dégradation des forêts denses sèches. Elles sont soumises aux facteurs climatiques et anthropiques. Cette étude vise à analyser la diversité floristique et la  dynamique des principales espèces dans la forêt classée de Koulbi. Les données ont été collectées dans 27 placeaux de 900 m2. Le diamètre (Dbh1,30 m) >5 cm et la hauteur des individus ont été mesurés. La régénération a été comptée et l’état sanitaire apprécié. Les indices de Shannon et de Piélou, la valeur d’importance écologique de l’espèce (IVI), la densité et la surface terrière ont été calculés. La distribution de Weibull a été appliquée à la structure des principales espèces. L’indice de Shanonn = 3,01 bits montre une diversité moyenne et l’indice de Pielou = 0,49 traduit la dominance de quelques espèces. Les espèces ayant un IVI significatif sont Anogeissus leiocarpa (DC.) Guill. Et Perr. (116,19), Pterocarpus erinaceus Poir. (21,66), Lannea barteri Oliv. Engl. (13,40), Adansonia digitata L. (12,92) et Vitellaria paradoxa Gaertn. (11,80). La principale espèce, A. leiocarpa présente une bonne densité tant au niveau des adultes (316 pieds/ha) que des juvéniles (667 pieds/ha). Sa structure diamétrique en «J renversé» est synonyme d’une bonne dynamique. Cependant, elle est menacée par la mortalité (9,27%) par endroit des sujets.Mots clés : Diversité floristique, régénération, mortalité, forêt classée de Koulbi

    Nuances of Public Diplomacy: China in Chilean Op-Eds (2018-2021)

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    This paper explores editorials and opinion columns published in four Chilean mainstream newspapers and analyzes how China is represented within the context of Chinese economic advances in the region and the contextual narratives surrounding bilateral relations. Through a content analysis of editorials and opinion pieces of elite media between 2018 and 2021, this study allows an understanding of how China and its growing influence are perceived locally. Ultimately, despite an overall alignment with China’s public diplomacy centered around an economic-commercial dimension, there are still nuances in how China is represented in Chilean op-eds

    Economic inequalities in burden of illness, diagnosis and treatment of five long-term conditions in England: panel study

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    We compared the distribution by wealth of self-reported illness burden (estimated from validated scales, biomarker and reported symptoms) for angina, cataract, depression, diabetes and osteoarthritis, with the distribution of self-reported medical diagnosis and treatment. We aimed to determine if the greater illness burden borne by poorer participants was matched by appropriately higher levels of diagnosis and treatment

    Resistant Hypertension and Obstructive Sleep Apnea in the Primary-Care Setting

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    We ascertained the prevalence of resistant hypertension (RH) among blacks and determined whether RH patients are at greater risk for obstructive sleep apnea (OSA) than hypertensives. Method. Data emanated from Metabolic Syndrome Outcome Study (MetSO), a study investigating metabolic syndrome among blacks in the primary-care setting. Sample of 200 patients (mean age = 63 ± 13 years; female = 61%) with a diagnosis of hypertension provided subjective and clinical data. RH was defined using the JNC 7and European Society guidelines. We assessed OSA risk using the Apnea Risk Evaluation System ARES), defining high risk as a total ARES score ≥6. Results. Overall, 26% met criteria for RH and 40% were at high OSA risk. Logistic regression analysis, adjusting for effects of age, gender, and medical co morbidities, showed that patients with RH were nearly 2.5 times more likely to be at high OSA risk, relative to those with hypertension (OR = 2.46, 95% CI: 1.03–5.88, P < .05). Conclusion. Our findings show that the prevalence of RH among blacks fell within the range of RH for the general hypertensive population (3–29%). However, patients with RH were at significantly greater risk of OSA compared to patients with hypertension

    Extraction, Storage and Eruption of Multiple Isolated Magma Batches in the Paired Mamaku and Ohakuri Eruption, Taupo Volcanic Zone, New Zealand

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    The Taupo Volcanic Zone (TVZ) is well known for its extraordinary rate of rhyolitic magma generation and caldera-forming eruptions. Less is known about how large volumes of rhyolitic magma are extracted and stored prior to eruption, and the role tectonics might play in the process of melt extraction and control of caldera eruption(s). Here we present a new model for the extraction, storage and simultaneous eruption of the >245 km3 paired Mamaku and Ohakuri magmas sourced from calderas centred ∼30 km apart (the Rotorua and Ohakuri calderas, respectively) in the central TVZ. The Mamaku and Ohakuri ignimbrites share a similar bulk pumice composition and the same phenocryst assemblage; however, bulk-rock compositions suggest several poorly mixed magma types in each erupted volume, which are randomly distributed throughout the eruptive deposits. To refine models of the pre-eruptive geometry of the magmatic system and discuss a possible origin for triggering of each eruption, we present an expanded database of matrix glass and quartz-hosted melt inclusion compositions along with the existing bulk-rock and mineral compositions. Major and trace element compositions show that the region produced five different magma batches, extracted from the same source region, and a continuous intermediate mush zone beneath the Mamaku-Ohakuri region is suggested here. These magma batches were most probably juxtaposed but isolated from each other in the upper crust, and evolved separately until eruption. The observed geochemical differences between the batches are likely to be generated by different extraction conditions of the rhyolitic melt from a slightly heterogeneous mush. The lack of evidence for more mafic recharge prior to eruption (for example, there are no bright cathodoluminescence rims on quartz crystals) suggests that a magmatic input is unlikely to be an eruption trigger. However, tectonic activity could be an efficient way to trigger the eruption of isolated magma batches, with the evacuation of one magma batch causing a disturbance to the local stress field and activating regionally linked faults, which then lead to the eruption of additional magma batches and associated caldera subsidence. In addition, the extensional tectonic regime coupled with a high heat flux could be the controlling factor in the emplacement of some of the shallowest and most SiO2-rich magmas on Eart
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