5,016 research outputs found

    Free initial wave packets and the long-time behavior of the survival and nonescape probabilities

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    The behavior of both the survival S(t) and nonescape P(t) probabilities at long times for the one-dimensional free particle system is shown to be closely connected to that of the initial wave packet at small momentum. We prove that both S(t) and P(t) asymptotically exhibit the same power-law decrease at long times, when the initial wave packet in momentum representation behaves as O(1) or O(k) at small momentum. On the other hand, if the integer m becomes greater than 1, S(t) and P(t) decrease in different power-laws at long times.Comment: 4 pages, 3 figures, Title and organization changed, however the results not changed, To appear in Phys. Rev.

    The impact of organisational external peer review on colorectal cancer treatment and survival in the Netherlands

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    Background: Organisational external peer review was introduced in 1994 in the Netherlands to improve multidisciplinary cancer care. We examined the clinical impact of this programme on colorectal cancer care. Methods: Patients with primary colorectal cancer were included from 23 participating hospitals and 7 controls. Hospitals from the intervention group were dichotomised by their implementation proportion (IP) of the recommendations from each peer review (high IP vs low IP). Outcome measures were the introduction of new multidisciplinary therapies and survival. Results: In total, 45 705 patients were included (1990-2010). Patients from intervention hospitals more frequently received adjuvant chemotherapy for stage III colon cancer. T2-3/M0 rectal cancer patients from hospitals with a high IP had a higher chance of receiving preoperative radiotherapy (OR 1.31, 95% CI 1.11-1.55) compared with the controls and low IP group (OR 0.75, 95% CI 0.63-0.88). There were no differences in the use of preoperative chemoradiation for T4/M0 rectal cancer. Survival was slightly higher in colon cancer patients from intervention hospitals but unrelated to the phase of the programme in which the hospital was at the time of diagnosis. Conclusions: Some positive effects of external peer review on cancer care were found, but the results need to be interpreted cautiously due to the ambiguity of the outcomes and possible confounding factors

    Operation of EMEP ‘supersites’ in the United Kingdom. Annual report for 2008.

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    As part of its commitment to the UN-ECE Convention on Long-range Transboundary Air Pollution the United Kingdom operates two ‘supersites’ reporting data to the Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (EMEP). This report provides the annual summary for 2008, the second full calendar year of operation of the first EMEP ‘supersite’ to be established in the United Kingdom. Detailed operational reports have been submitted to Defra every 3 months, with unratified data. This annual report contains a summary of the ratified data for 2008. The EMEP ‘supersite’ is located in central southern Scotland at Auchencorth (3.2oW, 55.8oN), a remote rural moorland site ~20 km south-west of Edinburgh. Monitoring operations started formally on 1 June 2006. In addition to measurements made specifically under this contract, the Centre for Ecology & Hydrology also acts as local site operator for measurements made under other UK monitoring networks: the Automated Urban and Rural Network (AURN), the UK Eutrophication and Acidification Network (UKEAP), the UK Hydrocarbons Network, and the UK Heavy Metals Rural Network. Some measurements were also made under the auspices of the ‘Air Pollution Deposition Processes’ contract. All these associated networks are funded by Defra. This report summarises the measurements made between January and December 2008, and presents summary statistics on average concentrations. The site is dominated by winds from the south-west, but wind direction data highlight potential sources of airborne pollutants (power stations, conurbations). The average diurnal patterns of gases and particles are consistent with those expected for a remote rural site. The frequency distributions are presented for data where there was good data capture throughout the whole period. Some components (e.g. black carbon) show log-normal frequency distributions, while other components (e.g. ozone) have more nearly normal frequency distributions. A case study is presented for a period in June 2008, showing the influence of regional air pollutants at this remote rural site. All the data reported under the contract are shown graphically in the Appendix

    Skin, Thermal and Umbilical Cord Care Practices for Neonates in Southern, Rural Zambia: A Qualitative Study

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    Background: In Choma District, southern Zambia, the neonatal mortality rate is approximately 40 per 1000 live births and, although the rate is decreasing, many deliveries take place outside of formal facilities. Understanding local practices during the postnatal period is essential for optimizing newborn care programs. Methods: We conducted 36 in-depth interviews, five focus groups and eight observational sessions with recently-delivered women, traditional birth attendants, and clinic and hospital staff from three sites, focusing on skin, thermal and cord care practices for newborns in the home. Results: Newborns were generally kept warm by application of hats and layers of clothing. While thermal protection is provided for preterm and small newborns, the practice of nighttime bathing with cold water was common. The vernix was considered important for the preterm newborn but dangerous for HIV-exposed infants. Mothers applied various substances to the skin and umbilical cord, with special practices for preterm infants. Applied substances included petroleum jelly, commercial baby lotion, cooking oil and breastmilk. The most common substances applied to the umbilical cord were powders made of roots, burnt gourds or ash. To ward off malevolent spirits, similar powders were reportedly placed directly into dermal incisions, especially in ill children. Conclusions: Thermal care for newborns is commonly practiced but co-exists with harmful practices. Locally appropriate behavior change interventions should aim to promote chlorhexidine in place of commonly-reported application of harmful substances to the skin and umbilical cord, reduce bathing of newborns at night, and address the immediate bathing of HIV-infected newborns

    COMPTEL observations of the inner galaxy

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    This paper presents a first global study of COMPTEL observations of the inner Galaxy in the energy range 0.75–10 MeV. Preliminary findings demonstrate COMPTEL’s capabilities for mapping the observed gamma radiation and disentangling the contributions from point sources and diffuse emission

    Anisotropic and strong negative magneto-resistance in the three-dimensional topological insulator Bi2Se3

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    We report on high-field angle-dependent magneto-transport measurements on epitaxial thin films of Bi2Se3, a three-dimensional topological insulator. At low temperature, we observe quantum oscillations that demonstrate the simultaneous presence of bulk and surface carriers. The magneto- resistance of Bi2Se3 is found to be highly anisotropic. In the presence of a parallel electric and magnetic field, we observe a strong negative longitudinal magneto-resistance that has been consid- ered as a smoking-gun for the presence of chiral fermions in a certain class of semi-metals due to the so-called axial anomaly. Its observation in a three-dimensional topological insulator implies that the axial anomaly may be in fact a far more generic phenomenon than originally thought.Comment: 6 pages, 4 figure

    Target and (Astro-)WISE technologies - Data federations and its applications

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    After its first implementation in 2003 the Astro-WISE technology has been rolled out in several European countries and is used for the production of the KiDS survey data. In the multi-disciplinary Target initiative this technology, nicknamed WISE technology, has been further applied to a large number of projects. Here, we highlight the data handling of other astronomical applications, such as VLT-MUSE and LOFAR, together with some non-astronomical applications such as the medical projects Lifelines and GLIMPS, the MONK handwritten text recognition system, and business applications, by amongst others, the Target Holding. We describe some of the most important lessons learned and describe the application of the data-centric WISE type of approach to the Science Ground Segment of the Euclid satellite.Comment: 9 pages, 5 figures, Proceedngs IAU Symposium No 325 Astroinformatics 201

    HIV-Infected Children in Rural Zambia Achieve Good Immunologic and Virologic Outcomes Two Years After Initiating Antiretroviral Therapy

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    Background: Many HIV-infected children in sub-Saharan Africa reside in rural areas, yet most research on treatment outcomes has been conducted in urban centers. Rural clinics and residents may face unique barriers to care and treatment. Methods: A prospective cohort study of HIV-infected children was conducted between September 2007 and September 2010 at the rural HIV clinic in Macha, Zambia. HIV-infected children younger than 16 years of age at study enrollment who received antiretroviral therapy (ART) during the study were eligible. Treatment outcomes during the first two years of ART, including mortality, immunologic status, and virologic suppression, were assessed and risk factors for mortality and virologic suppression were evaluated. Results: A total of 69 children entered the study receiving ART and 198 initiated ART after study enrollment. The cumulative probabilities of death among children starting ART after study enrollment were 9.0% and 14.4% at 6 and 24 months after ART initiation. Younger age, higher viral load, lower CD4+ T-cell percentage and lower weight-for-age z-scores at ART initiation were associated with higher risk of mortality. The mean CD4+ T-cell percentage increased from 16.3% at treatment initiation to 29.3% and 35.0% at 6 and 24 months. The proportion of children with undetectable viral load increased to 88.5% and 77.8% at 6 and 24 months. Children with longer travel times (≥5 hours) and those taking nevirapine at ART initiation, as well as children who were non-adherent, were less likely to achieve virologic suppression after 6 months of ART. Conclusions: HIV-infected children receiving treatment in a rural clinic experienced sustained immunologic and virologic improvements. Children with longer travel times were less likely to achieve virologic suppression, supporting the need for decentralized models of ART delivery
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