873 research outputs found

    Monodromy conjecture for log generic polynomials

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    A log generic hypersurface in P n with respect to a birational modification of P n is by definition the image of a generic element of a high power of an ample linear series on the modification. A log very-generic hypersurface is defined similarly but restricting to line bundles satisfying a non-resonance condition. Fixing a log resolution of a product f = f1 . . . fp of polynomials, we show that the monodromy conjecture, relating the motivic zeta function with the complex monodromy, holds for the tuple (f1, . . . , fp, g) and for the product fg, if g is log generic. We also show that the stronger version of the monodromy conjecture, relating the motivic zeta function with the Bernstein-Sato ideal, holds for the tuple (f1, . . . , fp, g) and for the product fg, if g is log very-generic. Even the case f = 1 is intricate, the proof depending on nontrivial properties of Bernstein-Sato ideals, and it singles out the class of log (very-) generic hypersurfaces as an interesting class of singularities on its own

    Monodromy conjecture for semi-quasihomogeneous hypersurfaces

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    We give a proof the monodromy conjecture relating the poles of motivic zeta functions with roots of b-functions for isolated quasihomogeneous hypersurfaces, and more generally for semi-quasihomogeneous hypersurfaces. We also give a strange generalization allowing a twist by certain differential forms

    The role of kidney registries in expediting large-scale collection of patient-reported outcome measures for people with chronic kidney disease

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    In this issue of Clinical Kidney Journal, Van der Willik et al. report findings from a pilot study where they introduced collection of patient-reported outcome measures (PROMs) into routine kidney care in Dutch dialysis centres. It is comparable to a registry-led PROMs initiative in Sweden, published in Clinical Kidney Journal in 2020. Both studies reported low average PROMs response rates with substantial between-centre variation, and both identified suboptimal patient and staff engagement as a key barrier to implementing PROMs in routine care for people with chronic kidney disease (CKD). This suggests that national kidney registries could be well placed to facilitate large-scale collection of PROMs data, but that they may require additional guidance on how to do this successfully. In this editorial, we discuss the current state-of-play of PROMs collection by kidney registries and provide an overview of what is (un)known about the feasibility and effectiveness of PROMs in CKD and other conditions. We anticipate that the fast-growing evidence base on whether, and how, PROMs can be of value in CKD settings will expedite registry-based PROMs collection, which will ultimately lead to more valuable and person-centred services and to enhanced health and well-being of people with CKD

    Upskilling health and care workers with augmented and virtual reality: protocol for a realist review to develop an evidence-informed programme theory.

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    From Europe PMC via Jisc Publications RouterHistory: ppub 2021-07-01, epub 2021-07-05Publication status: PublishedIntroductionAugmented reality (AR) and virtual reality (VR) are increasingly used to upskill health and care providers, including in surgical, nursing and acute care settings. Many studies have used AR/VR to deliver training, providing mixed evidence on their effectiveness and limited evidence regarding contextual factors that influence effectiveness and implementation. This review will develop, test and refine an evidence-informed programme theory on what facilitates or constrains the implementation of AR or VR programmes in health and care settings and understand how, for whom and to what extent they 'work'.Methods and analysisThis realist review adheres to the Realist And Meta-narrative Evidence Syntheses: Evolving Standards (RAMESES) standards and will be conducted in three steps: theory elicitation, theory testing and theory refinement. First, a search will identify practitioner, academic and learning and technology adoption theories from databases (MEDLINE, Scopus, CINAHL, Embase, Education Resources Information Center, PsycINFO and Web of Science), practitioner journals, snowballing and grey literature. Information regarding contexts, mechanisms and outcomes will be extracted. A narrative synthesis will determine overlapping configurations and form an initial theory. Second, the theory will be tested using empirical evidence located from the above databases and identified from the first search. Quality will be assessed using the Mixed Methods Appraisal Tool (MMAT), and relevant information will be extracted into a coding sheet. Third, the extracted information will be compared with the initial programme theory, with differences helping to make refinements. Findings will be presented as a narrative summary, and the MMAT will determine our confidence in each configuration.Ethics and disseminationEthics approval is not required. This review will develop an evidence-informed programme theory. The results will inform and support AR/VR interventions from clinical educators, healthcare providers and software developers. Upskilling through AR/VR learning interventions may improve quality of care and promote evidence-based practice and continued learning. Findings will be disseminated through conference presentations and peer-reviewed journal articles

    Patients' perceptions of information and education for renal replacement therapy: an independent survey by the European Kidney Patients' Federation on information and support on renal replacement therapy.

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    BACKGROUND: Selection of an appropriate renal replacement modality is of utmost importance for patients with end stage renal disease. Previous studies showed provision of information to and free modality choice by patients to be suboptimal. Therefore, the European Kidney Patients' Federation (CEAPIR) explored European patients' perceptions regarding information, education and involvement on the modality selection process. METHODS: CEAPIR developed a survey, which was disseminated by the national kidney patient organisations in Europe. RESULTS: In total, 3867 patients from 36 countries completed the survey. Respondents were either on in-centre haemodialysis (53%) or had a functioning graft (38%) at the time of survey. The majority (78%) evaluated the general information about kidney disease and treatment as helpful, but 39% did not recall being told about alternative treatment options than their current one. Respondents were more often satisfied with information provided on in-centre haemodialysis (90%) and transplantation (87%) than with information provided on peritoneal dialysis (79%) or home haemodialysis (61%), and were more satisfied with information from health care professionals vs other sources such as social media. Most (75%) felt they had been involved in treatment selection, 29% perceived they had no free choice. Involvement in modality selection was associated with enhanced satisfaction with treatment (OR 3.13; 95% CI 2.72-3.60). Many respondents (64%) could not remember receiving education on how to manage their kidney disease in daily life. Perceptions on information seem to differ between countries. CONCLUSIONS: Kidney patients reported to be overall satisfied with the information they received on their disease and treatment, although information seemed mostly to have been focused on one modality. Patients involved in modality selection were more satisfied with their treatment. However, in the perception of the patients, the freedom to choose an alternative modality showed room for improvement

    Термопружний стан шаруватих термочутливих циліндрів і куль за конвективно-променевого теплообміну

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    Розроблено методику розв’язування одновимірних статичних задач термопружності для шаруватих циліндрів і куль за конвективно-променевого нагрівання з урахуванням лінійної залежності коефіцієнтів теплопровідності та довільного характеру залежності інших фізико-механічних характеристик від температури. Задачі теплопровідності зведено, незалежно від кількості шарів, до розв’язування системи двох нелінійних алгебричних рівнянь. У задачах термопружності неперервні в межах кожного шару коефіцієнти рівнянь апроксимовано кусково-сталими функціями. Проведено числовий аналіз температурних полів і напружень у двошарових тілах.The method for solving one-dimensional static thermoelasticity problems is developed for layered cylinders and spheres under convective and radiation heating, taking into account linear dependence of heat conductivity coefficients and arbitrary character of dependence of other physical and mechanical characteristics on a temperature. Problems of heat conductivity have been reduced to the system of two nonlinear algebraic equations regardless of the number of layers. In the thermoelasticity problems the continuous within every layer coefficients of equations are approximated by piecewise constant functions. The numerical analysis of the temperature fields and stresses is conducted for two-layered bodies.Разработана методика решения одномерных статических задач термоупругости для слоистых цилиндров и сфер при конвективно-лучевом нагреве с учетом линейной зависимости коэффициентов теплопроводности и произвольного характера зависимости других физико-механических характеристик от температуры. Задачи теплопроводности сведены, независимо от количества слоев, к решению системы двух нелинейных алгебраических уравнений. В задачах термоупругости непрерывные в пределах каждого слоя коэффициенты уравнений аппроксимированы кусочно-постоянными функциями. Проведен численный анализ температурных полей и напряжений в двухслойных телах

    Распределение металлической фазы в синтетических алмазах типа «карбонадо»

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    Studying of a structural structure synthetic «carbonado» is spent by a method of electronic scanning microscopy. It is established, that the surface «carbonado» is covered by the large diamond crystals reaching 200 microns, having obviously expressed structure of growth. On a surface of these crystals observed drops of metal-catalyst (nickel) of a submicronic range. It is established, that the structure synthetic «carbonado» represents interpenetrating skeletons from diamond and ceramic-metal phases

    Willingness to participate in a randomized trial comparing catheters to fistulas for vascular access in incident hemodialysis patients: an international survey of nephrologists

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    BACKGROUND: Current guidelines favor fistulas over catheters as vascular access. Yet, the observational literature comparing fistulas to catheters has important limitations and biases that may be difficult to overcome in the absence of randomization. However, it is not clear if physicians would be willing to participate in a clinical trial comparing fistulas to catheters. OBJECTIVES: We also sought to elicit participants' opinions on willingness to participate in a future trial regarding catheters and fistulas. DESIGN: We created a three-part survey consisting of 19 questions. We collected demographic information, respondents' knowledge of the vascular access literature, appropriateness of current guideline recommendations, and their willingness to participate in a future trial. SETTING: Participants were recruited from Canada, Europe, Australia, and New Zealand. PARTICIPANTS: Participants include physicians and trainees who are involved in the care of end-stage renal disease patients requiring vascular access. MEASUREMENTS: Descriptive statistics were used to describe baseline characteristics of respondents according to geographic location. We used logistic regression to model willingness to participate in a future trial. METHODS: We surveyed nephrologists from Canada, Europe, Australia, and New Zealand to assess their willingness to participate in a randomized trial comparing fistulas to catheters in incident hemodialysis patients. RESULTS: Our results show that in Canada, 86 % of respondents were willing to participate in a trial (32 % in all patients; 54 % only in patients at high risk of primary failure). In Europe and Australia/New Zealand, the willingness to participate in a trial that included all patients was lower (28 % in Europe; 25 % in Australia/New Zealand), as was a trial that included patients at high risk of primary failure (38 % in Europe; 39 % in Australia/New Zealand). Nephrologists who have been in practice for a few years, saw a larger volume of patients, or self-identified as experts in vascular access literature were more likely to participate in a trial. LIMITATIONS: Survey distribution was limited to vascular access experts in participating European countries and ultimately led to a discrepancy in numbers of European to non-European respondents overall. Canadian views are likely over-represented in the overall outcomes. CONCLUSIONS: Our survey results suggest that nephrologists believe there is equipoise surrounding the optimal vascular access strategy and that a randomized controlled study should be undertaken, but restricted to those individuals with a high risk of primary fistula failure

    Diagnosis and treatment of hyponatremia : a systematic review of clinical practice guidelines and consensus statements

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    Background: Hyponatremia is a common electrolyte disorder. Multiple organizations have published guidance documents to assist clinicians in managing hyponatremia. We aimed to explore the scope, content, and consistency of these documents. Methods: We searched MEDLINE, EMBASE, and websites of guideline organizations and professional societies to September 2014 without language restriction for Clinical Practice Guidelines (defined as any document providing guidance informed by systematic literature review) and Consensus Statements (any other guidance document) developed specifically to guide differential diagnosis or treatment of hyponatremia. Four reviewers appraised guideline quality using the 23-item AGREE II instrument, which rates reporting of the guidance development process across six domains: scope and purpose, stakeholder involvement, rigor of development, clarity of presentation, applicability, and editorial independence. Total scores were calculated as standardized averages by domain. Results: We found ten guidance documents; five clinical practice guidelines and five consensus statements. Overall, quality was mixed: two clinical practice guidelines attained an average score of > 50% for all of the domains, three rated the evidence in a systematic way and two graded strength of the recommendations. All five consensus statements received AGREE scores below 60% for each of the specific domains. The guidance documents varied widely in scope. All dealt with therapy and seven included recommendations on diagnosis, using serum osmolality to confirm hypotonic hyponatremia, and volume status, urinary sodium concentration, and urinary osmolality for further classification of the hyponatremia. They differed, however, in classification thresholds, what additional tests to consider, and when to initiate diagnostic work-up. Eight guidance documents advocated hypertonic NaCl in severely symptomatic, acute onset ( 48 h) or asymptomatic cases, recommended treatments were NaCl 0.9%, fluid restriction, and cause-specific therapy for hypovolemic, euvolemic, and hypervolemic hyponatremia, respectively. Eight guidance documents recommended limits for speed of increase of sodium concentration, but these varied between 8 and 12 mmol/L per 24 h. Inconsistencies also existed in the recommended dose of NaCl, its initial infusion speed, and which second line interventions to consider. Conclusions: Current guidance documents on the assessment and treatment of hyponatremia vary in methodological rigor and recommendations are not always consistent
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