570 research outputs found
An unfitted Nitsche method for incompressible fluid-structure interaction using overlapping meshes
We consider the extension of the Nitsche method to the case of fluid–structure interaction problems on unfitted meshes. We give a stability analysis for the space semi-discretized problem and show how this estimate may be used to derive optimal error estimates for smooth solutions,irrespectively of the mesh/interface intersection. We also discuss different strategies for the time discretization, using either fully implicit or explicit coupling (loosely coupled) schemes. Some numerical examples illustrate the theoretical discussion
Numerical Computations with H(div)-Finite Elements for the Brinkman Problem
The H(div)-conforming approach for the Brinkman equation is studied
numerically, verifying the theoretical a priori and a posteriori analysis in
previous work of the authors. Furthermore, the results are extended to cover a
non-constant permeability. A hybridization technique for the problem is
presented, complete with a convergence analysis and numerical verification.
Finally, the numerical convergence studies are complemented with numerical
examples of applications to domain decomposition and adaptive mesh refinement.Comment: Minor clarifications, added references. Reordering of some figures.
To appear in Computational Geosciences, final article available at
http://www.springerlink.co
Robust flux error estimation of an unfitted Nitsche method for high-contrast interface problems
We prove an optimal error estimate for the flux variable for a stabilized unfitted Nitsche finite element method applied to an elliptic interface problem with discontinuous constant coefficients. Our result shows explicitly that this error estimate is totally independent of the diffusion coefficients
Statistical Analysis of Different Muon-antineutrino->Electron-antineutrino Searches
A combined statistical analysis of the experimental results of the LSND and
KARMEN \numubnueb oscillation search is presented. LSND has evidence for
neutrino oscillations that is not confirmed by the KARMEN experiment. This
joint analysis is based on the final likelihood results for both data sets. A
frequentist approach is applied to deduce confidence regions. At a combined
confidence level of 36%, there is no area of oscillation parameters compatible
with both experiments. For the complementary confidence of 1-0.36=64%, there
are two well defined regions of oscillation parameters (sin^2(2th),Dm^2)
compatible with both experiments.Comment: 25 pages, including 10 figures, submitted to Phys. Rev.
The incidence of liver injury in Uyghur patients treated for TB in Xinjiang Uyghur autonomous region, China, and its association with hepatic enzyme polymorphisms nat2, cyp2e1, gstm1 and gstt1.
BACKGROUND AND OBJECTIVE: Of three first-line anti-tuberculosis (anti-TB) drugs, isoniazid is most commonly associated with hepatotoxicity. Differences in INH-induced toxicity have been attributed to genetic variability at several loci, NAT2, CYP2E1, GSTM1and GSTT1, that code for drug-metabolizing enzymes. This study evaluated whether the polymorphisms in these enzymes were associated with an increased risk of anti-TB drug-induced hepatitis in patients and could potentially be used to identify patients at risk of liver injury. METHODS AND DESIGN: In a cross-sectional study, 2244 tuberculosis patients were assessed two months after the start of treatment. Anti-TB drug-induced liver injury (ATLI) was defined as an ALT, AST or bilirubin value more than twice the upper limit of normal. NAT2, CYP2E1, GSTM1 and GSTT1 genotypes were determined using the PCR/ligase detection reaction assays. RESULTS: 2244 patients were evaluated, there were 89 cases of ATLI, a prevalence of 4% 9 patients (0.4%) had ALT levels more than 5 times the upper limit of normal. The prevalence of ATLI was greater among men than women, and there was a weak association with NAT2*5 genotypes, with ATLI more common among patients with the NAT2*5*CT genotype. The sensitivity of the CT genotype for identifying patients with ATLI was 42% and the positive predictive value 5.9%. CT ATLI was more common among slow acetylators (prevalence ratio 2.0 (95% CI 0.95,4.20) )compared to rapid acetylators. There was no evidence that ATLI was associated with CYP2E1 RsaIc1/c1genotype, CYP2E1 RsaIc1/c2 or c2/c2 genotypes, or GSTM1/GSTT1 null genotypes. CONCLUSIONS: In Xinjiang Uyghur TB patients, liver injury was associated with the genetic variant NAT2*5, however the genetic markers studied are unlikely to be useful for screening patients due to the low sensitivity and low positive predictive values for identifying persons at risk of liver injury
Age-specific symptom prevalence in women 35–64 years old: A population-based study
<p>Abstract</p> <p>Background</p> <p>Symptom prevalence is generally believed to increase with age. The aim of this study was to evaluate the age specific prevalence of 30 general symptoms among Swedish middle-aged women.</p> <p>Methods</p> <p>A cross-sectional postal questionnaire study in seven Swedish counties in a random sample of 4,200 women 35–64 years old, with 2,991 responders. Thirty general symptoms included in the Complaint Score subscale of the Gothenburg Quality of Life Instrument were used.</p> <p>Results</p> <p>Four groups of age specific prevalence patterns were identified after adjustment for the influence of educational level, perceived health and mood, body mass index, smoking habits, use of hormone replacement therapy, and use of other symptom relieving therapy. Only five symptoms (insomnia, leg pain, joint pain, eye problems and impaired hearing) increased significantly with age. Eleven symptoms (general fatigue, headache, irritability, melancholy, backache, exhaustion, feels cold, cries easily, abdominal pain, dizziness, and nausea) decreased significantly with age. Two symptoms (sweating and impaired concentration) had a biphasic course with a significant increase followed by a significant decrease. The remaining twelve symptoms (difficulty in relaxing, restlessness, overweight, coughing, breathlessness, diarrhoea, chest pain, constipation, nervousness, poor appetite, weight loss, and difficulty in urinating) had stable prevalence with age.</p> <p>Conclusion</p> <p>Symptoms did not necessarily increase with age instead symptoms related to stress-tension-depression decreased.</p
Identification of female sex pheromone for monitoring the barred tooth striped moth, trichopteryx polycommata, a priority conservation species
Pheromone-baited traps can be excellent tools for sensitive detection of insects of conservation concern. Here, identification of the sex pheromone of Trichopteryx polycommata (Denis & Schiffermüller, 1775), an under-recorded UK priority species, is reported. In analyses of extracts of the pheromone glands of female T. polycommata by gas chromatography coupled to electroantennographic recording from the antenna of a male moth, a single active component was detected. This was identified as (Z,Z)-6,9-nonadecadiene (Z,Z6,9-19:H) by comparison of its mass spectrum and retention times with those of the synthetic standard. In a pilot field trial in Kent, UK, T. polycommata males were caught in pheromone traps baited with lures loaded with 1 mg and 2 mg (Z,Z)-6,9-19:H. Optimum lure loading was identified in a further five trials in Kent, Sussex and Lancashire where lures of 0, 0.001, 0.01, 0.1, 1, 2, 5 and 10 mg loadings were tested. Traps baited with 1 to 10 mg of ZZ6,9-19:H caught significantly more T. polycommata than traps baited with 0 mg and 0.001 mg. In a pilot survey of T. polycommata using pheromone lures around Morecambe Bay, UK, T. polycommata males were captured at 122 new sites within the three counties where trials took place, demonstrating the potential of pheromone monitoring to increase knowledge of abundance, distribution and ecology of this elusive species
“Excellence R Us”: university research and the fetishisation of excellence
The rhetoric of “excellence” is pervasive across the academy. It is used to refer to research outputs as well as researchers, theory and education, individuals and organisations, from art history to zoology. But does “excellence” actually mean anything? Does this pervasive narrative of “excellence” do any good? Drawing on a range of sources we interrogate “excellence” as a concept and find that it has no intrinsic meaning in academia. Rather it functions as a linguistic interchange mechanism. To investigate whether this linguistic function is useful we examine how the rhetoric of excellence combines with narratives of scarcity and competition to show that the hypercompetition that arises from the performance of “excellence” is completely at odds with the qualities of good research. We trace the roots of issues in reproducibility, fraud, and homophily to this rhetoric. But we also show that this rhetoric is an internal, and not primarily an external, imposition. We conclude by proposing an alternative rhetoric based on soundness and capacity-building. In the final analysis, it turns out that that “excellence” is not excellent. Used in its current unqualified form it is a pernicious and dangerous rhetoric that undermines the very foundations of good research and scholarship
Helicobacter cinaedi Induced Typhlocolitis in Rag-2-Deficient Mice
Background
Helicobacter cinaedi, an enterohepatic helicobacter species (EHS), is an important human pathogen and is associated with a wide range of diseases, especially in immunocompromised patients. It has been convincingly demonstrated that innate immune response to certain pathogenic enteric bacteria is sufficient to initiate colitis and colon carcinogenesis in recombinase-activating gene (Rag)-2-deficient mice model. To better understand the mechanisms of human IBD and its association with development of colon cancer, we investigated whether H. cinaedi could induce pathological changes noted with murine enterohepatic helicobacter infections in the Rag2[superscript −/−] mouse model.
Materials and Methods
Sixty 129SvEv Rag2[superscript −/−] mice mouse were experimentally or sham infected orally with H. cinaedi strain CCUG 18818. Gastrointestinal pathology and immune responses in infected and control mice were analyzed at 3, 6 and 9 months postinfection (MPI). H. cinaedi colonized the cecum, colon, and stomach in infected mice.
Results
H. cinaedi induced typhlocolitis in Rag2[superscript −/−] mice by 3 MPI and intestinal lesions became more severe by 9 MPI. H. cinaedi was also associated with the elevation of proinflammatory cytokines, interferon-γ, tumor-necrosis factor-α, IL-1β, IL-10; iNOS mRNA levels were also upregulated in the cecum of infected mice. However, changes in IL-4, IL-6, Cox-2, and c-myc mRNA expressions were not detected.
Conclusions
Our results indicated that the Rag2[superscript −/−] mouse model will be useful to continue investigating the pathogenicity of H. cinaedi, and to study the association of host immune responses in IBD caused by EHS.United States. National Institutes of Health (R01-0D011141)United States. National Institutes of Health (R01-CA067529)United States. National Institutes of Health (P30-ES002109)United States. National Institutes of Health (P01-CA026731
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