3,981 research outputs found

    Cocliques of maximal size in the prime graph of a finite simple group

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    In this paper we continue our investgation of the prime graph of a finite simple group started in http://arxiv.org/abs/math/0506294 (the printed version appeared in [1]). We describe all cocliques of maximal size for all finite simple groups and also we correct mistakes and misprints from our previous paper. The list of correction is given in Appendix of the present paper.Comment: published version with correction

    Knot Theory: from Fox 3-colorings of links to Yang-Baxter homology and Khovanov homology

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    This paper is an extended account of my "Introductory Plenary talk at Knots in Hellas 2016" conference We start from the short introduction to Knot Theory from the historical perspective, starting from Heraclas text (the first century AD), mentioning R.Llull (1232-1315), A.Kircher (1602-1680), Leibniz idea of Geometria Situs (1679), and J.B.Listing (student of Gauss) work of 1847. We spend some space on Ralph H. Fox (1913-1973) elementary introduction to diagram colorings (1956). In the second section we describe how Fox work was generalized to distributive colorings (racks and quandles) and eventually in the work of Jones and Turaev to link invariants via Yang-Baxter operators, here the importance of statistical mechanics to topology will be mentioned. Finally we describe recent developments which started with Mikhail Khovanov work on categorification of the Jones polynomial. By analogy to Khovanov homology we build homology of distributive structures (including homology of Fox colorings) and generalize it to homology of Yang-Baxter operators. We speculate, with supporting evidence, on co-cycle invariants of knots coming from Yang-Baxter homology. Here the work of Fenn-Rourke-Sanderson (geometric realization of pre-cubic sets of link diagrams) and Carter-Kamada-Saito (co-cycle invariants of links) will be discussed and expanded. Dedicated to Lou Kauffman for his 70th birthday.Comment: 35 pages, 31 figures, for Knots in Hellas II Proceedings, Springer, part of the series Proceedings in Mathematics & Statistics (PROMS

    Effects of temperature and glycerol and methanol-feeding profiles on the production of recombinant galactose oxidase in Pichia pastoris

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    Optimization of protein production from methanol-induced Pichia pastoris cultures is necessary to ensure high productivity rates and high yields of recombinant proteins. We investigated the effects of temperature and different linear or exponential methanol-feeding rates on the production of recombinant Fusarium graminearum galactose oxidase (EC 1.1.3.9) in a P. pastoris Mut+ strain, under regulation of the AOX1 promoter. We found that low exponential methanol feeding led to 1.5-fold higher volumetric productivity compared to high exponential feeding rates. The duration of glycerol feeding did not affect the subsequent product yield, but longer glycerol feeding led to higher initial biomass concentration, which would reduce the oxygen demand and generate less heat during induction. A linear and a low exponential feeding profile led to productivities in the same range, but the latter was characterized by intense fluctuations in the titers of galactose oxidase and total protein. An exponential feeding profile that has been adapted to the apparent biomass concentration results in more stable cultures, but the concentration of recombinant protein is in the same range as when constant methanol feeding is employed. (c) 2014 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 30:728-735, 201

    Individual and medical characteristics of adults presenting to an urban emergency department in Ghana

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    Background: The aims of this study were to characterize the patients seeking acute care for injury and noninjury complaints in an urban Emergency Department in Ghana in order to 1) inform the curriculum of the newly developed Emergency Medicine resident training program 2) improve treatment processes, and 3) direct future community-wide injury prevention policiesStudy Design: A prospective cross-sectional survey of patients 18 years or older seeking care in an urban Accident and Emergency Center (AEC) was conducted between 7/13/2009 and 7/30/2009. Questionnaires were administered by trained research staff and each survey took 10-15 minutes to complete. Patients were asked questions regarding demographics, overall health and chief complaint.Results: 254 patients were included in the sample. Participants’ chief complaints were classified as either medical or injury-related. Approximately one third (38%) of patients presented with injuries and 62% presented for medical complaints. The most common injury at presentation was due to a road traffic injury, followed by falls and assault/fight. The most common medical presentation was abdominal pain followed by difficulty breathing and fainting/ blackout. Only 13% arrived to AEC by ambulance and 51% were unable to ambulate at the time of presentation.Conclusion: Approximately one-third of non-fatal adult visits were for acute injury. Future research should focus on developing surveillance systems for both medical and trauma patients. Physicians that are specifically trained to manage both the acutely injured patient and the medical patient will serve this population well given the variety of patients that seek care at the AEC.Keywords: Emergency Medicine, Injury, Surveillance, Ghana, Characteristic

    Public perception of cross-infection control in dentistry

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Since the advent of HIV/AIDS at the beginning of the 1980s, concern has generated considerable impetus for change in cross-infection control procedures in dentistry. This process has been hastened partly by media coverage which, in tending to favour sensation over rational discourse, has played a not inconsiderable role in shaping public uderstanding and expectations. This study aimed to investigate public perceptions of cross-infection control in dentistry in Australia using a postal follow-up to the 1995 National Dental Telephone rate was 85.2 per cent. Concerns about the procedures used by their dentist to sterilize instruments were reported by 13.3 per cent of respondents overall, and this was greater among non-health-card-holders, individuals who mainly spoke a language other than English in the home, and those who reported a non-routine dental visiting pattern. Avoidance or delaying of dental visits due to the perceived cross-infection risk was reported by an overall 3.6 per cent of people, and this was higher among females and those who expressed concern about cross-infection control. The profession has a responsibility to ensure that information on the measures which have been taken to reduce the risk of cross-infection in dentisry is disseminated as widely and as clearly as possible so that undue public concern and avoidance of dental care are minimized.W. Murray Thomson, Judith F. Stewart, Knute D. Carter and A. John Spence

    Transit Timing and Duration Variations for the Discovery and Characterization of Exoplanets

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    Transiting exoplanets in multi-planet systems have non-Keplerian orbits which can cause the times and durations of transits to vary. The theory and observations of transit timing variations (TTV) and transit duration variations (TDV) are reviewed. Since the last review, the Kepler spacecraft has detected several hundred perturbed planets. In a few cases, these data have been used to discover additional planets, similar to the historical discovery of Neptune in our own Solar System. However, the more impactful aspect of TTV and TDV studies has been characterization of planetary systems in which multiple planets transit. After addressing the equations of motion and parameter scalings, the main dynamical mechanisms for TTV and TDV are described, with citations to the observational literature for real examples. We describe parameter constraints, particularly the origin of the mass/eccentricity degeneracy and how it is overcome by the high-frequency component of the signal. On the observational side, derivation of timing precision and introduction to the timing diagram are given. Science results are reviewed, with an emphasis on mass measurements of transiting sub-Neptunes and super-Earths, from which bulk compositions may be inferred.Comment: Revised version. Invited review submitted to 'Handbook of Exoplanets,' Exoplanet Discovery Methods section, Springer Reference Works, Juan Antonio Belmonte and Hans Deeg, Eds. TeX and figures may be found at https://github.com/ericagol/TTV_revie

    The Dutch Consumer Quality Index: an example of stakeholder involvement in indicator development

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    Background: Like in several other Western countries, in the Dutch health care system regulated competition has been introduced. In order to make this work, comparable information is required about the performance of health care providers in terms of effectiveness, safety and patient experiences. Without further coordination, external actors will all try to force health care providers to be transparent. For health care providers this might result in a situation in which they have to deliver data for several sets of indicators, defined by different actors. Therefore, in the Netherlands an effort is made to define national sets of performance indicators and related measuring instruments. In this article, the following questions are addressed, using patient experiences as an example: - When and how are stakeholders involved in the development of indicators and instruments that measure the patients' experiences with health care providers? - Does this involvement lead to indicators and instruments that match stakeholders' information needs? Discussion: The Dutch experiences show that it is possible to implement national indicator sets and to reach consensus about what needs to be measured. Preliminary evaluations show that for health care providers and health insurers the benefits of standardization outweigh the possible loss of tailor-made information. However, it has also become clear that particular attention should be given to the participation of patient/consumer organisations. Summary: Stakeholder involvement is complex and time-consuming. However, it is the only way to balance the information needs of all the parties that ask for and benefit from transparency, without frustrating the health care system.

    Early growth response gene-2 (Egr-2) regulates the development of B and T cells

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    The study was supported by Arthritis Research UK. Copyright @ 2011 Li et al.BACKGROUND: Understanding of how transcription factors are involved in lymphocyte development still remains a challenge. It has been shown that Egr-2 deficiency results in impaired NKT cell development and defective positive selection of T cells. Here we investigated the development of T, B and NKT cells in Egr-2 transgenic mice and the roles in the regulation of distinct stages of B and T cell development. METHODS AND FINDINGS: The expression of Egr1, 2 and 3 were analysed at different stages of T and B cell development by RT-PCT and results showed that the expression was strictly regulated at different stages. Forced expression of Egr-2 in CD2+ lymphocytes resulted in a severe reduction of CD4+CD8+ (DP) cells in thymus and pro-B cells in bone marrow, which was associated with reduced expression of Notch1 in ISP thymocytes and Pax5 in pro-B cells, suggesting that retraction of Egr-2 at the ISP and pro-B cell stages is important for the activation of lineage differentiation programs. In contrast to reduction of DP and pro-B cells, Egr-2 enhanced the maturation of DP cells into single positive (SP) T and NKT cells in thymus, and immature B cells into mature B cells in bone marrow. CONCLUSIONS: Our results demonstrate that Egr-2 expressed in restricted stages of lymphocyte development plays a dynamic, but similar role for the development of T, NKT and B cells.This article is provided by the Brunel Open Access publishing fund

    Improving healthcare delivery with new interactive visualization methods

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    Over the last years, the implementation and evolution of computer resources in hospital institutions has been improving both the financial and temporal efficiency of clinical processes, as well as the security in the transmission and maintenance of their data, also ensuring the reduction of clinical risk. Diagnosis, treatment and prevention of human illness are some of the most information-intensive of all intellectual tasks. Health providers often do not have or cannot find the information they need to respond quickly and appropriately to patient’s medical problems. Failure to review and follow up on patient’s test results in a timely manner, for example, represents a patient’s safety and malpractice concern. Therefore, it was sought to identify problems in a medical exams results management system and possible ways to improve this system in order to reduce both clinical risks and hospital costs. In this sense, a new medical exams visualization platform (AIDA-MCDT) was developed, specifically in the Hospital Center of Porto (CHP), with several new functionalities in order to make this process faster, intuitive and efficient, always guaranteeing the confidentiality and protection of patients’ personal data and significantly improving the usability of the system, leading to a better health care delivery.FCT - Fundação para a Ciência e a Tecnologia (UID/CEC/00319/2019
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