659 research outputs found

    The Effect of fuel and poison management on nuclear power systems

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    Statement of responsibility on title page reads: N.B. McLeod, M. Benedict, K. Uematsu, H.L. Witting, and K.S. Ram"September 15, 1961."Submitted by the first author as a Ph. D. thesis, Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1962"NYO-9715, TID 4500 Category, UC-80 Reactor Technology.""This work was done in part at the MIT Computation Center."Includes bibliographical references (p. 492-496)Report; June, 1959 - September, 1961Contract no. AT(30-1)-207

    "Dann machen halt alle mit." Eine qualitative Studie zu Beweggründen und Motiven für Hatespeech unter Schüler*innen

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    Das Thema Hatespeech rückt immer mehr in den Fokus der Öffentlichkeit und der Forschung. Im Gegensatz zu Hatespeech im Internet wird jedoch Hatespeech unter Jugendlichen, die von Angesicht zu Angesicht im Schulkontext ausgeübt wird, kaum beachtet. Hier setzt die vorliegende Studie an, in der Schüler*innen (n = 55), Lehrkräfte (n = 18) und Sozialpädagog*innen (n =16) auf der Basis leitfadengestützter Interviews dazu befragt wurden, was mögliche Beweggründe und Motive dafür sind, dass Schüler*innen Hatespeech in der Lebenswelt Schule und online ausüben. Die Ergebnisse zeigen, dass mögliche Beweggründe für Hatespeech Angst vor Statusverlust, Gruppendruck, Provokation, Spaß, politisch-ideologische Überzeugung und Kompensation von Frust- und Minderwertigkeitsgefühlen sind. Darüber hinaus wird verdeutlicht, dass sich hinter diesen Gründen für Hatespeech oftmals Grundmotive nach Macht und Zugehörigkeit abzeichnen. Die Ergebnisse werden in Bezug auf anschließende Forschung und praktische Implikationen diskutiert.Interest in the topic of hate speech has increased steadily in both the public realm and that of scientific research. Seldom addressed, however, is the proliferation of hate speech amongst adolescents, experienced face-to-face in the school context. To this end, the present study interviewed students (n = 55), teachers (n = 18) and social workers (n = 16), using guideline-based interviews to discuss reasons and motives for students practicing hate speech both online and in the school environment. Results showed that reported reasons for hate speech include fear of diminishing status, peer group pressure, provocation, fun, political-ideological convictions, and compensation for feelings of frustration and inferiority. Additionally, reasons for hate speech are often associated with the basic motives need for power and affiliation. The findings are discussed in relation to future research and practical implications

    Overscreening of magnetic impurities in dx2y2d_{x^2-y^2} wave superconductors

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    We consider the screening of a magnetic impurity in a dx2y2d_{x^2-y^2} wave superconductor. The properties of the dx2y2d_{x^2-y^2} state lead to an unusual behavior in the impurity magnetic susceptibility, the impurity specific heat and in the quasiparticle phase shift which can be used to diagnose the nature of the condensed state. We construct an effective theory for this problem and show that it is equivalent to a multichannel (one per node) non-marginal Kondo problem with linear density of states and coupling constant J. There is a quantum phase transition from an unscreened impurity state to an overscreened Kondo state at a critical value J_c which varies with Δ0\Delta_0, the superconducting gap away from the nodes. In the overscreened phase, the impurity Fermi level ϵf\epsilon_f and the amplitude Δ\Delta of the ground state singlet vanish at J_c like Δ0exp(const./Δ)\Delta_0 \exp(- const. / \Delta) and J-J_c respectively. We derive the scaling laws for the susceptibility and specific heat in the overscreened phase at low fields and temperatures.Comment: 43 pages; shortened version; a number of typos have been correcte

    The Syk tyrosine kinase is required for skin inflammation in an in vivo mouse model of epidermolysis bullosa acquisita.

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    The inflammatory form of epidermolysis bullosa acquisita is caused by autoantibodies against type VII collagen (C7), a component of the dermal-epidermal junction. We have previously shown that myeloid Src-family kinases mediate skin inflammation triggered by anti-C7 antibodies. Here we identify the Syk tyrosine kinase as a critical component of autoantibody-induced skin inflammation downstream of Src-family kinases. Immobilized C7-anti-C7 immune complexes triggered neutrophil activation and Syk phosphorylation in a Src-family kinase-dependent manner. Bone marrow chimeric mice lacking Syk in their hematopoietic compartment were completely protected from skin inflammation triggered by anti-C7 antibodies despite normal circulating anti-C7 levels. Syk deficiency abrogated the accumulation of CXCL2, IL-1beta and LTB4 at the site of inflammation and resulted in defective in vivo neutrophil recruitment. Syk-/- neutrophils had a normal intrinsic migratory capacity but failed to release CXCL2 or LTB4 upon activation by immobilized C7-anti-C7 immune complexes, indicating a role for Syk in the amplification of the inflammation process. These results identify Syk as a critical component of skin inflammation in a mouse model of epidermolysis bullosa acquisita and as a potential therapeutic target in epidermolysis bullosa acquisita and other mechanistically related inflammatory skin diseases such as bullous pemphigoid

    Metabolic biomarkers assessed with PET/CT predict sex-specific longitudinal outcomes in patients with diffuse large B-cell lymphoma

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    In many cancers, including lymphoma, males have higher incidence and mortality than females. Emerging evidence demonstrates that one mechanism underlying this phenomenon is sex differences in metabolism, both with respect to tumor nutrient consumption and systemic alterations in metabolism, i.e., obesity. We wanted to determine if visceral fat and tumor glucose uptake with fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) could predict sex-dependent outcomes in patients with diffuse large B-cell lymphoma (DLBCL). We conducted a retrospective analysis of 160 patients (84 males; 76 females) with DLBCL who had imaging at initial staging and after completion of therapy. CT-based relative visceral fat area (rVFA), PET-based SUVmax normalized to lean body mass (SULmax), and end-of-treatment FDG-PET 5PS score were calculated. Increased rVFA at initial staging was an independent predictor of poor OS only in females. At the end of therapy, increase in visceral fat was a significant predictor of poor survival only in females. Combining the change in rVFA and 5PS scores identified a subgroup of females with visceral fat gain and high 5PS with exceptionally poor outcomes. These data suggest that visceral fat and tumor FDG uptake can predict outcomes in DLBCL patients in a sex-specific fashion

    Safety and Efficacy of Endoscopic Retrograde Cholangiopancreatography in Patients with Post-Liver Transplant Biliary Complications: Results of a Cohort Study with Long-Term Follow-Up

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    BACKGROUND/AIMS: Endoscopic retrograde cholangiopancreatography (ERCP) is the standard approach for the management of biliary complications in liver transplant patients; however, its safety and efficacy have not been established in this setting. This study was performed to evaluate the safety and long-term efficacy of ERCP in transplant patients. METHODS: The case reports of 1,500 liver transplant patients were reviewed. Orthotopic liver transplantation (OLT) patients were matched 1:2 with non-OLT patients and followed-up for long-term outcome (median, 7.4 years). RESULTS: Of the 1,500 liver transplant patients, 94 (6.3%) underwent 150 ERCPs after OLT. Anastomotic strictures were present in 45 patients, biliary stones in 24, biliary leaks in 7, papillary stenosis in 2, and primary sclerosing cholangitis in 1. An ERCP success rate of 90.7% was achieved; biliary stenting led to resolution of the bile leak in 7/7 (100%) patients, and biliary stones were removed in 21/24 (87.5%) patients. In addition, 34 of 45 patients with anastomotic stricture underwent endoscopic dilation. We obtained complete resolution in 22/34 (64.7%) patients. OLT patients did not show a higher probability of complications (odds ratio [OR], 1.04), of pancreatitis (OR, 0.80) or of bleeding (OR, 1.34). CONCLUSIONS: ERCP is safe and effective for the treatment of post-OLT biliary complications, has a low rate of pancreatitis and results in a durable effect

    Influence of freeze-thaw events on carbon dioxide emission from soils at different moisture and land use

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    BACKGROUND: The repeated freeze-thaw events during cold season, freezing of soils in autumn and thawing in spring are typical for the tundra, boreal, and temperate soils. The thawing of soils during winter-summer transitions induces the release of decomposable organic carbon and acceleration of soil respiration. The winter-spring fluxes of CO(2 )from permanently and seasonally frozen soils are essential part of annual carbon budget varying from 5 to 50%. The mechanisms of the freeze-thaw activation are not absolutely clear and need clarifying. We investigated the effect of repeated freezing-thawing events on CO(2 )emission from intact arable and forest soils (Luvisols, loamy silt; Central Germany) at different moisture (65% and 100% of WHC). RESULTS: Due to the measurement of the CO(2 )flux in two hours intervals, the dynamics of CO(2 )emission during freezing-thawing events was described in a detailed way. At +10°C (initial level) in soils investigated, carbon dioxide emission varied between 7.4 to 43.8 mg C m(-2)h(-1 )depending on land use and moisture. CO(2 )flux from the totally frozen soil never reached zero and amounted to 5 to 20% of the initial level, indicating that microbial community was still active at -5°C. Significant burst of CO(2 )emission (1.2–1.7-fold increase depending on moisture and land use) was observed during thawing. There was close linear correlation between CO(2 )emission and soil temperature (R(2 )= 0.86–0.97, P < 0.001). CONCLUSION: Our investigations showed that soil moisture and land use governed the initial rate of soil respiration, duration of freezing and thawing of soil, pattern of CO(2 )dynamics and extra CO(2 )fluxes. As a rule, the emissions of CO(2 )induced by freezing-thawing were more significant in dry soils and during the first freezing-thawing cycle (FTC). The acceleration of CO(2 )emission was caused by different processes: the liberation of nutrients upon the soil freezing, biological activity occurring in unfrozen water films, and respiration of cold-adapted microflora

    Pharmacological Undertreatment of Coronary Risk Factors in Patients with Psoriasis: Observational Study of the Danish Nationwide Registries

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    BACKGROUND: Patients with psoriasis have increased prevalence of coronary risk factors and limited recent results have suggested that these risk factors are undertreated in patients with psoriasis. This may contribute to the increased risk of cardiovascular diseases observed in patients with psoriasis. OBJECTIVE: To examine the pharmacological treatment of coronary risk factors in patients with severe psoriasis treated with biologic agents in a real-world setting. METHODS AND FINDINGS: Medical history of patients with severe psoriasis treated with biologic agents in the time period 2007-09 was retrieved from a Danish nationwide registry (DERMBIO). Individual-level linkage of nationwide administrative registries of hospitalizations, concomitant medications, and socioeconomic status was performed to gain insights into the use of pharmacological treatment. A total of 693 patients (mean age 46.1 ± 12.7 years, 65.7% male) with severe psoriasis treated with biologic agents were identified. Hypertension, hypercholesterolemia, and diabetes mellitus were identified in 16.6%, 9.2%, and 6.7% of cases, respectively. Patients with severe psoriasis were significantly less likely to receive cardiovascular pharmacotherapy compared to age, sex, and coronary risk factor matched controls. In psoriatic patients with hypertension 27.7% received no antihypertensive pharmacotherapy. Patients with dyslipidemia received cholesterol-lowering medications in 55.8% of cases and patients with diabetes mellitus received angiotensin converting enzyme inhibitors/angiotensin II receptor blockers and cholesterol-lowering medications in 42.1% and 23.7% of cases, respectively. Similar results were found for the subset of patients with >1 coronary risk factor and for high risk patients with established atherosclerotic disease. CONCLUSION: This nationwide study of patients with severe psoriasis demonstrated substantial undertreatment of coronary risk factors. Increased focus on identifying cardiovascular risk factors and initiation of preventive cardiovascular pharmacotherapy in patients with psoriasis is warranted

    Culture-Independent Microbiological Analysis of Foley Urinary Catheter Biofilms

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    Background: Prevention of catheter-associated urinary tract infection (CAUTI), a leading cause of nosocomial disease, is complicated by the propensity of bacteria to form biofilms on indwelling medical devices [1,2,3,4,5]. Methodology/Principal Findings: To better understand the microbial diversity of these communities, we report the results of a culture-independent bacterial survey of Foley urinary catheters obtained from patients following total prostatectomy. Two patient subsets were analyzed, based on treatment or no treatment with systemic fluoroquinolone antibiotics during convalescence. Results indicate the presence of diverse polymicrobial assemblages that were most commonly observed in patients who did not receive systemic antibiotics. The communities typically contained both Gram-positive and Gramnegative microorganisms that included multiple potential pathogens. Conclusion/Significance: Prevention and treatment of CAUTI must take into consideration the possible polymicrobial nature of any particular infection
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