4,098 research outputs found

    High Energy Gamma-Ray Emission From Blazars: EGRET Observations

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    We will present a summary of the observations of blazars by the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO). EGRET has detected high energy gamma-ray emission at energies greater than 100 MeV from more that 50 blazars. These sources show inferred isotropic luminosities as large as 3×10493\times 10^{49} ergs s1^{-1}. One of the most remarkable characteristics of the EGRET observations is that the gamma-ray luminosity often dominates the bolometric power of the blazar. A few of the blazars are seen to exhibit variability on very short time-scales of one day or less. The combination of high luminosities and time variations seen in the gamma-ray data indicate that gamma-rays are an important component of the relativistic jet thought to characterize blazars. Currently most models for blazars involve a beaming scenario. In leptonic models, where electrons are the primary accelerated particles, gamma-ray emission is believed to be due to inverse Compton scattering of low energy photons, although opinions differ as to the source of the soft photons. Hardronic models involve secondary production or photomeson production followed by pair cascades, and predict associated neutrino production.Comment: 16 pages, 7 figures, style files included. Invited review paper in "Observational Evidence for Black Holes in the Universe," 1999, ed. S. K. Chakrabarti (Dordrecht: Kluwer), 215-23

    Proximal Resection Margin in Ivor-Lewis Oesophagectomy for Cancer

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    OBJECTIVE: The purpose of this study was to investigate whether a long proximal oesophageal resection margin (PRM) is associated with improved survival after oesophagectomy for cancer and to identify the optimal margin to aim for in this patient group. METHODS: A prospectively maintained database identified 174 patients who underwent Ivor-Lewis oesophagectomy for cancer. Demographic, clinical, and pathological data were collected. X-tile software was used to identify the optimal resection point. Two models were analysed: single point resection with comparison of two groups (short and long), and two resection points with three groups (short, medium, and long) to provide a range. RESULTS: The median PRM was 4.0 cm (interquartile range: 2.5-6.0 cm). After adjustment for significant confounders, multivariable Cox PH analysis demonstrated that the optimal resection margin was 1.7 cm, and in the three-group analysis the optimum PRM was between 1.7 and 3 cm. In the two-group analysis, the long margin had no effect on DFS (p = 0.37), but carried a significantly improved overall survival (hazard ratio [HR] = 0.46, 95 % confidence interval [CI] 0.25-0.87, p = 0.02). In the three-group analysis, the medium and long groups had improved OS compared with the short group (on average 54 %, HR ≥ 0.45, p ≤ 0.04). The 5-year disease-free and overall survival rates were highest in the medium PRM group (48 and 57 % respectively). CONCLUSIONS: Optimal survival following oesophagectomy for cancer is achieved with a PRM > 1.7 cm, but a PRM > 3 cm does not yield a further survival advantage. Thus, the optimal PRM is likely to be between 1.7 and 3 cm

    Trial Protocol: Randomised controlled trial of the effects of very low calorie diet, modest dietary restriction, and sequential behavioural programme on hunger, urges to smoke, abstinence and weight gain in overweight smokers stopping smoking

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    Background\ud Weight gain accompanies smoking cessation, but dieting during quitting is controversial as hunger may increase urges to smoke. This is a feasibility trial for the investigation of a very low calorie diet (VLCD), individual modest energy restriction, and usual advice on hunger, ketosis, urges to smoke, abstinence and weight gain in overweight smokers trying to quit. \ud \ud Methods\ud This is a 3 armed, unblinded, randomized controlled trial in overweight (BMI > 25 kg/m2m^2), daily smokers (CO > 10 ppm); with at least 30 participants in each group. Each group receives identical behavioural support and NRT patches (25 mg(8 weeks),15 mg(2 weeks),10 mg(2 weeks)). The VLCD group receive a 429-559 kcal/day liquid formula beginning 1 week before quitting and continuing for 4 weeks afterwards. The modest energy restricted group (termed individual dietary and activity planning(IDAP)) engage in goal-setting and receive an energy prescription based on individual basal metabolic rate(BMR) aiming for daily reduction of 600 kcal. The control group receive usual dietary advice that accompanies smoking cessation i.e. avoiding feeling hungry but eating healthy snacks. After this, the VLCD participants receive IDAP to provide support for changing eating habits in the longer term; the IDAP group continues receiving this support. The control group receive IDAP 8 weeks after quitting. This allows us to compare IDAP following a successful quit attempt with dieting concurrently during quitting. It also aims to prevent attrition in the unblinded, control group by meeting their need for weight management. Follow-up occurs at 6 and 12 months. \ud \ud Outcome measures include participant acceptability, measured qualitatively by semi-structured interviewing and quantitatively by recruitment and attrition rates. Feasibility of running the trial within primary care is measured by interview and questionnaire of the treatment providers. Adherence to the VLCD is verified by the presence of urinary ketones measured weekly. Daily urges to smoke, hunger and withdrawal are measured using the Mood and Physical Symptoms Scale-Combined (MPSS-C) and a Hunger Craving Score (HCS). 24 hour, 7 day point prevalence and 4-week prolonged abstinence (Russell Standard) is confirmed by CO < 10 ppm. Weight, waist and hip circumference and percentage body fat are measured at each visit. \ud \ud Trial Registration\ud Current controlled trials ISRCTN83865809\ud \u

    Climate and land-use change during the late Holocene at Lake Ledro (southern Alps, Italy)

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    International audienceThis paper investigates the relative influences of climatic and anthropogenic factors in explaining environmental and societal changes in the southern Alps, Italy. We investigate a deep sediment core (LL081) from Lake Ledro (652 m a.s.l.). Environmental changes are reconstructed through multiproxy analysis, that is, pollen-based vegetation and climate reconstruction, magnetic susceptibility (MS), lake level, and flood frequency, and the paper focuses on the climate and land-use changes which occurred during the late Holocene. For this time interval, Lake Ledro records high mean water table, increasing amount of pollen-based precipitation, and more erosive conditions. Therefore, while a more humid late Holocene in the southern Alps has the potential to reinforce the forest presence, pollen evidence suggests that anthropogenic activities changed the impact of this regional scenario. Land-use activity (forest clearance for pastoralism, farming, and arboriculture) opened up the large vegetated slopes in the catchment of Lake Ledro, which in turn magnified the erosion related to the change in the precipitation pattern. The record of an almost continuous human occupation for the last 4100 cal. BP is divided into several land-use phases. On the one hand, forest redevelopments on abandoned or less cultivated areas appear to be climatically induced as they occurred in relation with well-known events such as the 2.8-kyr cold event and the ‘Little Ice Age’. On the other hand, climatically independent changes in land use or habitat modes are observed, such as the late-Bronze-Age lake-dwellings abandonment, the human population migration at c. 1600 cal. BP, and the period of the Black Death and famines at 600 cal. BP

    Transmission of equine influenza virus during an outbreak is characterized by frequent mixed infections and loose transmission bottlenecks.

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    The ability of influenza A viruses (IAVs) to cross species barriers and evade host immunity is a major public health concern. Studies on the phylodynamics of IAVs across different scales - from the individual to the population - are essential for devising effective measures to predict, prevent or contain influenza emergence. Understanding how IAVs spread and evolve during outbreaks is critical for the management of epidemics. Reconstructing the transmission network during a single outbreak by sampling viral genetic data in time and space can generate insights about these processes. Here, we obtained intra-host viral sequence data from horses infected with equine influenza virus (EIV) to reconstruct the spread of EIV during a large outbreak. To this end, we analyzed within-host viral populations from sequences covering 90% of the infected yards. By combining gene sequence analyses with epidemiological data, we inferred a plausible transmission network, in turn enabling the comparison of transmission patterns during the course of the outbreak and revealing important epidemiological features that were not apparent using either approach alone. The EIV populations displayed high levels of genetic diversity, and in many cases we observed distinct viral populations containing a dominant variant and a number of related minor variants that were transmitted between infectious horses. In addition, we found evidence of frequent mixed infections and loose transmission bottlenecks in these naturally occurring populations. These frequent mixed infections likely influence the size of epidemics

    Clinical effectiveness and cost-effectiveness of endobronchial and endoscopic ultrasound relative to surgical staging in potentially resectable lung cancer: results from the ASTER randomised controlled trial

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    Copyright @ Queen’s Printer and Controller of HMSO 2012. This work was produced by Sharples et al. under the terms of a commissioning contract issued by the Secretary of State for Health.Objective: To assess the clinical effectiveness and cost-effectiveness of endosonography (followed by surgical staging if endosonography was negative), compared with standard surgical staging alone, in patients with non-small cell lung cancer (NSCLC) who are otherwise candidates for surgery with curative intent. Design: A prospective, international, open-label, randomised controlled study, with a trialbased economic analysis. Setting: Four centres: Ghent University Hospital, Belgium; Leuven University Hospitals,Belgium; Leiden University Medical Centre, the Netherlands; and Papworth Hospital, UK. Participants: Inclusion criteria: known/suspected NSCLC, with suspected mediastinal lymph node involvement; otherwise eligible for surgery with curative intent; clinically fit for endosonography and surgery; and no evidence of metastatic disease. Exclusion criteria: previous lung cancer treatment; concurrent malignancy; uncorrected coagulopathy; and not suitable for surgical staging. Interventions: Study patients were randomised to either surgical staging alone (n = 118) or endosonography followed by surgical staging if endosonography was negative (n = 123). Endosonography diagnostic strategy used endoscopic ultrasound-guided fine-needle aspiration combined with endobronchial ultrasound-guided transbronchial needle aspiration, followed by surgical staging if these tests were negative. Patients with no evidence of mediastinal metastases or tumour invasion were referred for surgery with curative intent. If evidence of malignancy was found, patients were referred for chemoradiotherapy. Main outcome measures: The main clinical outcomes were sensitivity (positive diagnostic test/nodal involvement during any diagnostic test or thoracotomy) and negative predictive value (NPV) of each diagnostic strategy for the detection of N2/N3 metastases, unnecessary thoracotomy and complication rates. The primary economic outcome was cost–utility of the endosonography strategy compared with surgical staging alone, up to 6 months after randomisation, from a UK NHS perspective. Results: Clinical and resource-use data were available for all 241 patients, and complete utilities were available for 144. Sensitivity for detecting N2/N3 metastases was 79% [41/52; 95% confidence interval (CI) 66% to 88%] for the surgical arm compared with 94% (62/66; 95% CI 85% to 98%) for the endosonography strategy (p = 0.02). Corresponding NPVs were 86% (66/77; 95% CI 76% to 92%) and 93% (57/61; 95% CI 84% to 97%; p = 0.26). There were 21/118 (18%) unnecessary thoracotomies in the surgical arm compared with 9/123 (7%) in the endosonography arm (p = 0.02). Complications occurred in 7/118 (6%) in the surgical arm and 6/123 (5%) in the endosonography arm (p = 0.78): one pneumothorax related to endosonography and 12 complications related to surgical staging. Patients in the endosonography arm had greater EQ-5D (European Quality of Life-5 Dimensions) utility at the end of staging (0.117; 95% CI 0.042 to 0.192; p = 0.003). There were no other significant differences in utility. The main difference in resource use was the number of thoracotomies: 66% patients in the surgical arm compared with 53% in the endosonography arm. Resource use was similar between the groups in all other items. The 6-month cost of the endosonography strategy was £9713 (95% CI £7209 to £13,307) per patient versus £10,459 (£7732 to £13,890) for the surgical arm, mean difference £746 (95% CI –£756 to £2494). The mean difference in quality-adjusted life-year was 0.015 (95% CI –0.023 to 0.052) in favour of endosonography, so this strategy was cheaper and more effective. Conclusions: Endosonography (followed by surgical staging if negative) had higher sensitivity and NPVs, resulted in fewer unnecessary thoracotomies and better quality of life during staging, and was slightly more effective and less expensive than surgical staging alone. Future work could investigate the need for confirmatory mediastinoscopy following negative endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), the diagnostic accuracy of EUS-FNA or EBUS-TBNA separately and the delivery of both EUSFNA or EBUS-TBNA by suitably trained chest physicians.This project was funded by the NIHR Health Technology Assessment programm

    Bioavailability, Antipsoriatic Efficacy and Tolerability of a New Light Cream with Mometasone Furoate 0.1%

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    Mometasone furoate, a potent glucocorticoid (class III) with a favorable benefit/risk ratio, has emerged as a standard medication for the treatment of inflammatory skin disorders. The purpose of the investigation presented here was to determine the noninferiority of a topical mometasone formulation, a light cream (O/W 60/40 emulsion) with mometasone furoate 0.1% (water content of 33%) versus marketed comparators. Using the vasoconstrictor assay, a strong blanching effect of the new cream (called Mometasone cream) comparable to that of a mometasone comparator, a fatty cream with mometasone furoate 0.1%, could be demonstrated. Thus, the topical bioavailability of the active ingredient mometasone furoate (0.1%) was regarded to be similar for Mometasone cream and the mometasone comparator. Using the psoriasis plaque test, a strong antipsoriatic effect comparable to that of the mometasone comparator was found for Mometasone cream after 12 days of occlusive treatment. A nearly identical reduction in the mean infiltrate thickness and similar mean AUC values were noted with both formulations confirmed by clinical assessment data. The noninferiority of Mometasone cream to its active comparator with re-spect to the AUC of change to baseline in infiltrate thickness was demonstrated. Both medications were well tolerated. Overall, Mometasone cream and the mometasone comparator showed similar efficacy and tolerability. Mometasone cream, in addition to its high potency and good tolerability, provides the properties of a light cream, which might make this new medication particularly suitable for application on acutely inflamed and sensitive skin. Copyright (C) 2012 S. Karger AG, Base

    The Law and Policy of Child Maltreatment

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    Each year in the United States some four million children are reported to child protective services and hundreds of thousands of children are confirmed victims of maltreatment. This chapter provides a brief overview of the civil and criminal law’s response to child abuse and neglect. It summarizes the major federal statutes that provide funding to the states to support both civil and criminal law responses to maltreatment. It discusses the division of responsible for responding to child maltreatment between the federal and state governments (federalism). It also provides a summary of the constitutional framework for handling both civil and criminal child maltreatment cases

    On Semiclassical Limits of String States

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    We explore the relation between classical and quantum states in both open and closed (super)strings discussing the relevance of coherent states as a semiclassical approximation. For the closed string sector a gauge-fixing of the residual world-sheet rigid translation symmetry of the light-cone gauge is needed for the construction to be possible. The circular target-space loop example is worked out explicitly.Comment: 12 page

    Electro-Magnetic Nucleon Form Factors and their Spectral Functions in Soliton Models

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    It is demonstrated that in simple soliton models essential features of the electro-magnetic nucleon form factors observed over three orders of magnitude in momentum transfer tt are naturally reproduced. The analysis shows that three basic ingredients are required: an extended object, partial coupling to vector mesons, and relativistic recoil corrections. We use for the extended object the standard skyrmion, one vector meson propagator for both isospin channels, and the relativistic boost to the Breit frame. Continuation to timelike tt leads to quite stable results for the spectral functions in the regime from the 2- or 3-pion threshold to about two rho masses. Especially the onset of the continuous part of the spectral functions at threshold can be reliably determined and there are strong analogies to the results imposed on dispersion theoretic approaches by the unitarity constraint.Comment: 24 pages, (RevTeX), 5 PS-figures; Data points in fig.2 and corresponding references added. Final version, to be published in Z.Physik
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