1,137 research outputs found

    Inactivation of the major hemolysin gene influences expression of the nonribosomal peptide synthetase gene swrA in the insect pathogen Serratia sp. strain SCBI

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    Hemolysins are important virulence factors for many bacterial pathogens, including Serratia marcescens. The role of the major hemolysin gene in the insect pathogen Serratia sp. SCBI was investigated using both forward and reverse genetics approaches. Introduction of the major hemolysin gene into Escherichia coli resulted in a gain of both virulence and hemolytic activity. Inactivation of this hemolysin in Serratia sp. SCBI resulted in loss of hemolysis, but did not attenuate insecticidal activity. Unexpectedly, inactivation of the hemolysin gene in Serratia sp. SCBI resulted in significantly increased motility as well as increased antimicrobial activity. qRT-PCR analysis of mutants with a disrupted hemolysin gene showed a dramatic increase in mRNA levels of a nonribosomal peptide synthetase gene, swrA, which produces the surfactant serrawettin W2. Mutation of the swrA gene in Serratia sp. SCBI resulted in highly variable antibiotic activity, motility, virulence and hemolysis phenotypes that were dependent on the site of disruption within this 17.75 KB gene. When introduced into E. coli, swrA increases rates of motility and confers antimicrobial activity. While it is unclear how inactivation of the major hemolysin gene influences expression of swrA, these results suggest swrA plays an important role in motility and antimicrobial activity in Serratia sp. SCBI

    ĂśberprĂĽfung eines Zusammenhangs zwischen des Vitamin D Haushaltes und dem Auftreten von Zervixdysplasien

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    Die Vitamin D Wirkungen in Bezug auf den Kalziumstoffwechsel sind seit langem bekannt. In den letzten Jahren wurden aber auch andere Effekte von Vitamin D entdeckt (u.a. antiinflammatorische, antiproliferative, antiinvasive, antiangiogenetische, immunmodulatorische sowie die Induktion von Apoptose und Differenzierung). Vor allem ein möglicher Zusammenhang zwischen verminderten Vitamin D Spiegeln und dem erhöhten Auftreten verschiedener Krebsarten erweckte großes Interesse in der Forschung. Studien, die einen präzisen Zusammenhang zwischen Vitamin D und dem Zervixkarzinom untersuchten, sind jedoch rar und inkonsistent. Allerdings konnte eine Korrelation zwischen der Inzidenz- & Mortalitätsrate des Zervixkarzinoms und dem Breitengrad und damit der Intensität der UV-B Strahlung, welche zur endogenen Vitamin D Synthese benötigt wird, aufgezeigt werden. Des Weiteren wurden bereits verschiedene Therapiestudien mit Vitamin D bei Zervixdysplasien durchgeführt, welche erfolgversprechende Ansätze zeigten. Diese Beobachtungen gaben den Anlass zur Untersuchung eines Zusammenhangs zwischen niedrigen Vitamin D Spiegeln und dem Auftreten von Zervixdysplasien, welche mittels Pap-Abstrich detektiert und durch eine Biopsie mit anschließender histologischer Einteilung bestätigt werden können. Die vorliegende Studie sollte eruieren, ob Patientinnen mit auffälligem Pap-Abstrich (Pap III und höher) niedrigere Vitamin D Spiegel aufweisen als Patientinnen mit unauffälligem Pap-Abstrich (Pap II und niedriger). Des Weiteren wurden die Vitamin D Spiegel von Patientinnen mit unterschiedlichen histologisch gesicherten Zervixdysplasien (CIN 1, CIN 2, CIN 3) beziehungsweise ohne histologisches Korrelat miteinander verglichen. Da eine Infektion mit Humanen Papillomviren (HPV) die Hauptursache für die Entstehung des Zervixkarzinoms darstellt, wurden zusätzlich die Vitamin D Spiegel von Patientinnen mit aktuellem oder in der Vergangenheit positivem HPV-Test, mit denen von Patientinnen mit negativem HPV-Test verglichen. Insgesamt konnten 215 Patientinnen aus Rheinland-Pfalz und dem Saarland in die Studie eingeschlossen werden. Mittels Varianzanalyse wurden die Mittelwerte der Vitamin D Spiegel in den einzelnen Gruppen miteinander verglichen. Da Patientinnen, die Vitamin D substituierten (n=46) signifikant höhere Vitamin D Spiegel aufwiesen (p < 0,001), wurde einerseits das gesamte Patientenkollektiv betrachtet und andererseits alle Patientinnen, die eine Vitamin D Substitution angaben, ausgeschlossen. Insgesamt befanden sich 73% der Patientinnen (n=157) (bzw. 79,9% der Patientinnen ohne Vitamin D Substitution (n=135 von 169)) in einer Vitamin D Insuffizienz oder schlechter (< 30 ng/ml). Inadäquate Vitamin D Spiegel scheinen in Südwestdeutschland demnach stark präsent. In keiner der untersuchten Gruppen (unauffälliger Pap vs. auffälliger Pap; kein histologisches Korrelat vs. CIN1 vs. CIN2 vs. CIN3; HPV-Test negativ vs. positiv) zeigte sich ein signifikanter Unterschied der Vitamin D Spiegel, auch nicht nach Ausschluss der Patientinnen mit Vitamin D Substitution. Obwohl die vorliegende Studie keine signifikanten Unterschiede der Vitamin D Spiegel zwischen den einzelnen Gruppen feststellen konnte, zeigt der Blick in die Literatur, dass es womöglich trotzdem einen Zusammenhang zwischen Zervixdysplasien und niedrigen Vitamin D Spiegeln gibt. Die vaginale Vitamin D Therapie scheint im Falle einer leichtgradigen Dysplasie ein erfolgversprechendes, ergänzendes, einfaches, komplikationsarmes und kostengünstiges Therapiekonzept, um dem Fortschreiten einer Dysplasie entgegenzuwirken, bzw. deren Entstehung möglicherweise sogar zu verhindern. Es sind weitere Studien notwendig, um eindeutige Aussagen zu diesem Thema treffen zu können. Nichtsdestotrotz konnte in dieser Studie eine erschreckende Anzahl an Patientinnen mit inadäquaten Vitamin D Spiegeln identifiziert werden, weshalb das Thema Vitamin D und Vitamin D Mangel im klinischen Alltag vielleicht präsenter sein sollte und eine Vitamin D Therapie eventuell häufiger in Betracht gezogen werden könnte, als dies momentan der Fall scheint.The effects of vitamin D on the calcium metabolism are well known for a long time. In recent years also other effects of vitamin D were observed (as antiinflammatory, antiproliferative, antiinvasive, antiangiogenic, immunomodulatory, as well as induction of apoptosis and differentiation). Especially a possible correlation between low vitamin D serum levels and a higher incidence of different cancer sites aroused a big interest in research. However, studies who analysed a specific correlation between vitamin D and cervical cancer are rare and inconsistent. Though, a correlation between incidence and mortality rates of cervical cancer and latitude and therewith the intensity of UV-B radiation, which is necessary for endogenous vitamin D synthesis, was found. Additionally, there exist different studies, which examined a vitamin D treatment on cervical dysplasia and which showed promising results. Due to these observations a correlation between low vitamin D serum levels and the occurrence of cervical dysplasia was analysed, diagnosed by pap smears and confirmed by biopsies with following histological classification. The aim of the present study was to investigate if patients with abnormal pap smears (pap III and higher) have lower vitamin D serum levels than patients with normal pap smears (pap II and lower). Furthermore, vitamin D serum levels of patients with different cervical dysplasia (CIN 1, CIN 2, CIN 3) and with no histological confirmed dysplasia were compared. Because an infection with human papillomavirus is the leading cause of developing cervical carcinoma, the vitamin D serum levels of patients with positive HPV test in the present or past were compared with patients with negative HPV test. Altogether, 215 patients from Rhineland-Palatinate and Saarland were included into the study. An analysis-of-variance was used to compare mean vitamin D serum levels between the different groups. Patients with vitamin D intake (n=46) showed significant higher vitamin D serum levels (p < 0,001). As a consequence, these patients were excluded in a second analysis. 73% of all patients (n=157) (respectively 79,9% of the patients without vitamin D intake (n=135 of 169)) had a vitamin D insufficiency or worse (< 30 ng/ml). Therefore, inadequate vitamin D serum levels seem highly to be present in the south-western part of Germany. Mean vitamin D serum levels showed no significant difference in all analysed subgroups (normal vs. abnormal pap smear; no histological dysplasia vs. CIN 1 vs. CIN 2 vs. CIN 3; positive vs. negative HPV test), even after excluding patients with vitamin D intake. Although the present study shows no significant difference between the mean vitamin D serum levels in all subgroups, there seems to be evidence of a possible correlation between cervical dysplasia and lower vitamin D serum levels (based on research in literature). A vaginal vitamin D treatment appears to be a promising, complementary, simple, safe and cost-efficient therapy concept, which could counteract the progression of cervical dysplasia and maybe even prevent its genesis. More studies are needed to make a clear statement. Nevertheless, the present study showed an alarming number of patients with inadequate vitamin D serum levels, for which reason the issue of vitamin D deficiency should perhaps be more present in the clinical routine and vitamin D treatment is possibly more needed than it is maybe currently practised

    Probabilistic characterization and synthesis of complex driven systems

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    Thesis (Ph.D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2000.Includes bibliographical references (leaves 194-204).Real-world systems that have characteristic input-output patterns but don't provide access to their internal states are as numerous as they are difficult to model. This dissertation introduces a modeling language for estimating and emulating the behavior of such systems given time series data. As a benchmark test, a digital violin is designed from observing the performance of an instrument. Cluster-weighted modeling (CWM), a mixture density estimator around local models, is presented as a framework for function approximation and for the prediction and characterization of nonlinear time series. The general model architecture and estimation algorithm are presented and extended to system characterization tools such as estimator uncertainty, predictor uncertainty and the correlation dimension of the data set. Furthermore a real-time implementation, a Hidden-Markov architecture, and function approximation under constraints are derived within the framework. CWM is then applied in the context of different problems and data sets, leading to architectures such as cluster-weighted classification, cluster-weighted estimation, and cluster-weighted sampling. Each application relies on a specific data representation, specific pre and post-processing algorithms, and a specific hybrid of CWM. The third part of this thesis introduces data-driven modeling of acoustic instruments, a novel technique for audio synthesis. CWM is applied along with new sensor technology and various audio representations to estimate models of violin-family instruments. The approach is demonstrated by synthesizing highly accurate violin sounds given off-line input data as well as cello sounds given real-time input data from a cello player.by Bernd Schoner.Ph.D

    Vocational education and training and employment services in Malta

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    This country monograph is the result of a request from the European Commission (Directorate-General for Employment and Social Affairs) in the context of the Employment Policy Reviews launched by the latter in the future member states in 1999. According to this request, the key aim of the country monographs is to provide up-to-date, detailed information and analysis on the vocational education and training systems and structures as well as on the public and private employment services in order to support the monitoring of the Joint Assessment Papers of Employment Priorities (JAP). This analysis is considered to provide a useful input enabling the future member states and the European Commission to identify the most important needs and gaps. In particular, the analysis aims at providing: (1) an instrument to assess the progress made by the countries to increase the responsiveness of their education and training systems to labour market needs; this assessment is addresses particularly the challenges and priorities related to the development of lifelong learning; (2) a tool to assess the effectiveness of the public and private employment services to assist both young and adult unemployed people and those threatened by unemployment to enter the labour market; and (3) a basis for positioning the development trends of these systems in relation to those in EU member states. The work has been conducted by a team of national, EU and ETF experts, under the responsibility of the European Training Foundation (ETF) and with the support of the Employment Training Corporation (ETC). The method of work combined the use of desk research and field visits in the capital and also in some selected regions. The final document has been prepared by the European Training Foundation and therefore, reflects primarily an ETF viewpoint. The preparation of the monographs has also benefited from a close consultation process with representatives of the national authorities. The latter were informed about this work right from the beginning of the process and they were invited to provide their opinion on the final draft. In addition, a seminar was organised on 27 September 2002 in Brussels with the aim of presenting and discussing the documents with the national authorities of the future member states as well as with the European Commission. This monograph also reflects the outcomes of this seminar and further discussions and comments from the country. The document makes use of quantitative indicators from international institutions as well as national sources. As discussed during the 27 September meeting, it should be acknowledged that in relation to indicators used in the EU, some data are still missing, while others might refer to different realities. Therefore, figures must be interpreted with caution, taking into account that statistics should be complemented by more qualitative assessments. Further analytical work will be needed to improve the picture and in particular the positioning of developments in the country towards developments in the EU.peer-reviewe

    Book review: Transport for suburbia: Beyond the automobile age, by Paul Mees

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    JTLU vol 5, no 2, pp 121-122 (2012)This book review summarizes and evaluates Transport for Suburbia: Beyond the Automobile Age, by Paul Mees (Earthscan Publishing, 2010). The argument in Transport for Suburbia is that density is not a necessary prerequisite for an effective transit system, and that transfers can be used as a tool to expand the scope of a transit network. Mees presents this argument and his suggestions for improving transit service through a series of narratives about car culture, land use, and best and worst case transit system scenarios

    Catalysts and magnets: built environment effects on bicycle commuting

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    University of Minnesota Master of Science thesis. September 2013. Major: Civil Engineering. Advisor: David M. Levinson, Xinyu Cao, 1 computer file (PDF); viii, 71 pages, appendix A.What effects do bicycle infrastructure and the built environment have on people's decisions to commute by bicycle? While many studies have considered this question, commonly employed methodologies fail to address the unique statistical challenge of modeling such a low mode share. Additionally, self selection effects that are not adequately accounted for may lead to overestimation of built environment impacts. This study addresses these two key issues by using a zero-inflated negative binomial model to jointly estimate participation in and frequency of commuting by bicycle, controlling for demographics, residential preferences, and travel attitudes. The findings suggest a strong self selection effect and modest contributions of bicycle accessibility: that bicycle lanes act as ``magnets" to attract bicyclists to a neighborhood, rather than being the ``catalyst" that encourages non-bikers to shift modes. The results have implications for planners and policymakers attempting to increase bicycling mode share via the strategic infrastructure development

    Nice Stations: An Exploration of Nice Ride Bike Share Accessibility and Station Choice

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    Little is known about how people integrate bike share trip segments into their daily travel. In this study, we evaluate how people navigate from place to place using the Nice Ride Minnesota bike share system in the Minneapolis-St. Paul metropolitan area. We measure changes in job accessibility due to the addition of Nice Ride stations and develop a theoretical model for bike share station choice. The mapped results suggest that Nice Ride provides the strongest job accessibility improvement at the 30-minute threshold in a band just beyond the central business district where walking would not be feasible. We then model people's choice of origin station to evaluate their sensitivity to time spent walking, distance, and a set of station amenity and neighborhood control variables. As expected, people prefer to use stations that do not require deviating from the shortest path to reach a station. For commuters, each additional minute of walking decreases a station’s chance of being chosen, regardless of the overall trip length. Commuters also chose stations closer to parks. Conversely, users making non-work trips are sensitive to the ratio of walking to biking time (with a preference for time spent biking). Stations in neighborhoods with lower crime rates were more likely to be chosen for all trip purposes. The results from this study are important for planners who need a better understanding of bike share user behavior to design or optimize their system. The findings also provide a strong foundation for future research about bike share system modeling

    Academic Entitlement in the Context of Learning Styles

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    This study explores the linkages between students&rsquo; sense of entitlement and their approaches to learning, based on survey research at a large public university in Canada.&nbsp; Through literature review and pilot testing, a questionnaire instrument was developed that measures four constructs:&nbsp; academic entitlement, deep learning, surface learning and strategic learning.&nbsp; Survey responses (n=1=2116) suggest that students approach learning in mixed ways, and that approaches to learning intersect with students&rsquo; sense of entitlement in complex ways.&nbsp; Overall, students&rsquo; scores on the sense of entitlement scale were found to be moderate, challenging some of the assertions about today&rsquo;s students that have been made in the popular press.&nbsp
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