1,044 research outputs found

    Magnetostriction of a Superconductor: -Results from the Critical-State Model

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    In many cases, the critical-state theory can be treated as a suffi ciently accurate approximation for the modelling of the magnetic properties of superconductors. In the present work, the magnetostrictive hysteresis is computed for a quite general case of the modified Kim-Anderson model. The results obtained reproduce many features of the giant magnetostriction (butterfly-shaped curves) reported in the literature for measurements made on single-crystal samples of the high-temperature superconductor Bi2Sr2CaCu2O8Bi_2Sr_2CaCu_2O_8. It is shown that addition of a contribution to the magnetostriction in the superconducting state which is of similar origin as in the normal state, offers a broader phenomenological interpretation of the complex magnetostriction hysteresis found in such heavy-fermion compounds as UPt3UPt_3, URu2Si2URu_2Si_2 or UBe13UBe_{13}.Comment: 9 LaTeX pages, 4 Postscript figures, WWW version available at http://is.dal.ca/~zkoziol/super.htm

    What Does an Exemplary Middle School Mathematics Teacher Look Like? The Use of a Professional Development Rubric

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    A School University Research Network (SURN) committee composed of current mathematics teachers, central office math supervisors, building administrators, mathematicians, and mathematics educators researched numerous sources regarding best practices in mathematics instruction. The resulting professional development rubric synthesizes their findings and can serve a professional development role by providing teachers and administrators with a tool to develop clarity and consensus on best mathematics instructional practices, and how these practices are implemented in the classroom. It is also being used as a tool for cooperating teachers in their supervision of student teachers and as a reflective method for self-evaluation

    On learning to teach English teachers: A textured portrait of mentoring

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    Smith et al provide a textured portrait of the mentoring of novice English teacher educators. They describe how their talk in the mentoring sessions helped them to interrogate English content and methods, reflect on English methods course design, learn meaningfully from practice, and rethink assumptions about preservice teachers as learners

    Characteristics and homogeneity of N6-methylation in human genomes.

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    A novel DNA modification, N-6 methylated deoxyadenosine (m6dA), has recently been discovered in eukaryotic genomes. Despite its low abundance in eukaryotes, m6dA is implicated in human diseases such as cancer. It is therefore important to precisely identify and characterize m6dA in the human genome. Here, we identify m6dA sites at nucleotide level, in different human cells, genome wide. We compare m6dA features between distinct human cells and identify m6dA characteristics in human genomes. Our data demonstrates for the first time that despite low m6dA abundance, the m6dA mark does often occur consistently at the same genomic location within a given human cell type, demonstrating m6dA homogeneity. We further show, for the first time, higher levels of m6dA homogeneity within one chromosome. Most m6dA are found on a single chromosome from a diploid sample, suggesting inheritance. Our transcriptome analysis not only indicates that human genes with m6dA are associated with higher RNA transcript levels but identifies allele-specific gene transcripts showing haplotype-specific m6dA methylation, which are implicated in different biological functions. Our analyses demonstrate the precision and consistency by which the m6dA mark occurs within the human genome, suggesting that m6dA marks are precisely inherited in humans

    fenics_ice 1.0: A framework for quantifying initialisation uncertainty for time-dependent ice-sheet models

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    Mass loss due to dynamic changes in ice sheets is a significant contributor to sea level rise, and this contribution is expected to increase in the future. Numerical codes simulating the evolution of ice sheets can potentially quantify this future contribution. However, the uncertainty inherent in these models propagates into projections of sea level rise is and hence crucial to understand. Key variables of ice sheet models, such as basal drag or ice stiffness, are typically initialized using inversion methodologies to ensure that models match present observations. Such inversions often involve tens or hundreds of thousands of parameters, with unknown uncertainties and dependencies. The computationally intensive nature of inversions along with their high number of parameters mean traditional methods such as Monte Carlo are expensive for uncertainty quantification. Here we develop a framework to estimate the posterior uncertainty of inversions and project them onto sea level change projections over the decadal timescale. The framework treats parametric uncertainty as multivariate Gaussian and exploits the equivalence between the Hessian of the model and the inverse covariance of the parameter set. The former is computed efficiently via algorithmic differentiation, and the posterior covariance is propagated in time using a time-dependent model adjoint to produce projection error bars. This work represents an important step in quantifying the internal uncertainty of projections of ice sheet models.</p

    LHC Beam Instrumentation

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    Six years before the scheduled commissioning of the LHC at CERN, the basic list of beam instruments has been established. This early date is needed due to the impact of the mechanical design of some detectors (mainly the beam position detectors) on the cryogenic part of the machine as well as for other projects due to the long R&D period (emittance measurements, tune and chromaticity diagnostics and control). This paper gives a detailed overview of the basic requirements and specifications of all beam instruments foreseen for transfer lines and main rings [1]

    LHC Beam Instrumentation Conceptual Design Report

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    The instruments and diagnostic systems considered for the LHC are presented and their specifications and expected performance discussed. Their task will be to measure the essential beam properties, establish diagnosis, and give information on beam behaviour. The diagnostic systems will be essential during the running-in period. Precise and reliable information from them are a prerequisite for operational optimization.During the last years, basic design and parameters of the LHC have evolved continuously. The present description of beam instrumentation and diagnostics is based on the most recent set of nominal LHC parameters

    Nox1/4 inhibition exacerbates age dependent perivascular inflammation and fibrosis in a model of spontaneous hypertension

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    Hypertension is associated with oxidative stress and perivascular inflammation, critical contributors to perivascular fibrosis and accelerated vascular ageing. Oxidative stress can promote vascular inflammation, creating options for potential use of NADPH oxidase inhibitors in pharmacological targeting of perivascular inflammation and its consequences. Accordingly, we characterized age-related changes in oxidative stress and immune cell infiltration in normotensive (WKY) and spontaneously hypertensive rats (SHRs). Subsequently, we used pharmacological inhibitors of Nox1 (ML171) and Nox1/Nox4 (GKT137831; 60 mg/kg), to modulate NADPH oxidase activity at the early stage of spontaneous hypertension and investigated their effects on perivascular inflammation and fibrosis. Results: Ageing was associated with a progressive increase of blood pressure as well as an elevation of the total number of leukocytes, macrophages and NK cells infiltrating perivascular adipose tissue (PVAT) in SHRs but not in WKY. At 1 month of age, when blood pressure was not yet different, only perivascular NK cells were significantly higher in SHR. Spontaneous hypertension was also accompanied by the higher perivascular T cell accumulation, although this increase was age independent. Aortic Nox1 and Nox2 mRNA expression increased with age only in SHR but not in WKY, while age-related increase of Nox4 mRNA in the vessels has been observed in both groups, it was more pronounced in SHRs. At early stage of hypertension (3-months) the most pronounced differences were observed in Nox1 and Nox4. Surprisingly, GKT137831, dual inhibitor of Nox1/4, therapy increased both blood pressure and perivascular macrophage infiltration. Mechanistically, this was linked to increased expression of proinflammatory chemokines expression (CCL2 and CCL5) in PVAT. This inflammatory response translated to increased perivascular fibrosis. This effect was likely Nox4 dependent as the Nox1 inhibitor ML171 did not affect the development of spontaneous hypertension, perivascular macrophage accumulation, chemokine expression nor adventitial collagen deposition. In summary, spontaneous hypertension promotes ageing-associated perivascular inflammation which is exacerbated by Nox4 but not Nox1 pharmacological inhibition

    AWARENESS OF LYME BORRELIOSIS OF THE PATIENTS OF TERNOPIL REGIONAL TB DISPENSARY

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    Background. Lyme disease has many clinical features similar tothose in sarcoidosis and tuberculosis. Epidemiological data in the world, in particular in Ukraine, proves the increase in Lyme borreliosis incidence. Ternopil region is endemic with Lyme borreliosis. Objective. The research was aimed to investigate the prevalence of infection with Borrelia burgdorferi and epidemiology features of borreliosis among the patients of Ternopil Regional TB Dispensary. Methods. In total, 29 patients were admitted to Departments of Differential Diagnostic, TB Therapy and TB Surgery of Ternopil Regional TB Dispensary in October 2016-January 2017. All the surveyed answered the questions of an integrated international questionnaire, where they noted the area and a number of tick bites, described the removal method, noted the survey for borreliosis pathogen and complaints after tick bites. Results. It was established that 5 respondents had a history of tick bites episodes, but only in one case the patient was examined of borreliosis. Tick bites were noticed in 3 patients with sarcoidosis and 1 with tuberculosis (TB) and exudative pleurisy, respectively. Conclusions. The absence of appeals for medical care, lack of sufficient information on Lyme borreliosis and disuse of preventive measures for tick bites by the interviewed patients of Ternopil regional TB dispensary departments proves the need of improvement of health education on Lyme borreliosis (LB) among this category of population. 24 (82.7%) of 29 respondents did not remember the tick bite. The symptoms of (LB) are similar to those in sarcoidosis and tuberculosis (pleural lesions, heart, joints, nervous system, skin), and the presence of tick bites gives the reasons to examine these patients of Borrelia burgdorferi senso lato

    Aspirin but not ibuprofen use is associated with reduced risk of prostate cancer: A PLCO Study

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    Background: Although most epidemiological studies suggest that non-steroidal anti-inflammatory drug use is inversely associated with prostate cancer risk, the magnitude and specificity of this association remain unclear. Methods: We examined self-reported aspirin and ibuprofen use in relation to prostate cancer risk among 29 450 men ages 55–74 who were initially screened for prostate cancer from 1993 to 2001 in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Men were followed from their first screening exam until 31 December 2009, during which 3575 cases of prostate cancer were identified. Results: After adjusting for potential confounders, the hazard ratios (HRs) of prostate cancer associated with \u3c1 and 1 pill of aspirin daily were 0.98 (95% confidence interval (CI), 0.90–1.07) and 0.92 (95% CI: 0.85–0.99), respectively, compared with never use (P for trend 0.04). The effect of taking at least one aspirin daily was more pronounced when restricting the analyses to men older than age 65 or men who had a history of cardiovascular-related diseases or arthritis (HR (95% CI); 0.87 (0.78–0.97), 0.89 (0.80–0.99), and 0.88 (0.78–1.00), respectively). The data did not support an association between ibuprofen use and prostate cancer risk. Conclusion: Daily aspirin use, but not ibuprofen use, was associated with lower risk of prostate cancer risk
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