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Search Results: 1 - 10 of 180699 matches for " Hans De Beenhouwer "
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Towards Multitarget Testing in Molecular Microbiology
Deborah Steensels,Anne Vankeerberghen,Hans De Beenhouwer
International Journal of Microbiology , 2013, DOI: 10.1155/2013/121057
Abstract: Advantages of PCR assays over more conventional culture-based diagnostics include significantly higher sensitivities and shorter turnaround times. They are particularly useful when patient treatment has already been initiated or for specimens that may contain microorganisms that are slow-growing, difficult to culture, or for which culture methods do not exist. However, due to genome variability, single target testing might lead to false-negative results. This paper focuses on examples from our own experiences and the literature to provide insight into the limitations of single target testing in molecular biology. Lessons learned from these experiences include the careful design of diagnostic assays, preferably multitargeted, the importance of investigating the incidence and epidemiology of infection in detail, the frequent participation in appropriate quality assurance schemes, and the importance of continuous attentiveness by investigators when confronted with inconsistent results. In conclusion, multitargeted testing in microbiological molecular assays should be a rule. 1. Introduction The introduction of molecular methods has had a positive impact in many areas of diagnostic microbiology. These tests have been proven to be often more sensitive and specific than classical testing, and they are particularly useful for specimens that may contain fastidious, slow-growing, or unculturable microorganisms or when patient treatment has already been initiated. In addition, identification based on genetic traits is more objective than the interpretation of conventional phenotypic characteristics. The development of a commercial or an in-house molecular assay begins with a review of the current literature. This provides information concerning the choices of target genes used in previous studies, potential specificity or sensitivity problems, and additional information of clinical importance (e.g., cutoff values). All known subtypes or other known sequence variants (mutations, insertions, deletions, etc.) of the pathogen should be included in the specificity testing if feasible [1]. Once an appropriate target is selected, primers and probes can be designed. However, due to genome variability, single target testing might lead to false-negative results. Indeed, many variants exist today, but not all variants are known, and new variants emerge constantly according to the ever present Darwin’s evolution theory. This paper focuses on examples from our own experiences and the literature to provide insight into how single target testing might lead to false-negative
An interlaboratory comparison of ITS2-PCR for the identification of yeasts, using the ABI Prism 310 and CEQ8000 capillary electrophoresis systems
Thierry De Baere, Anne Van Keerberghen, Peter Van Hauwe, Hans De Beenhouwer, An Boel, Gerda Verschraegen, Geert Claeys, Mario Vaneechoutte
BMC Microbiology , 2005, DOI: 10.1186/1471-2180-5-14
Abstract: Although ITS2 size estimations on both systems differed and separate libraries had to be constructed for each system, both approaches had the same discriminatory power with regard to the 44 reference strains, identical identifications were obtained for 39/ 40 clinical isolates in both laboratories and strains from 51 samples were correctly identified using CEQ8000, when compared to phenotypic identification.Identification of yeasts with ITS2-PCR followed by fragment analysis can be carried out on different capillary electrophoresis systems with comparable discriminatory power.The clinical importance of yeast infections has increased during the last decades, not only because the number of yeast infections has increased, but also because yeast infections have become a frequent cause of morbidity and mortality in immunocompromised patients [1]. Besides the higher frequency there is also an important change in the spectrum of the species causing clinical infections. Whereas Candida albicans has long been considered as the clinically most important species of the genus, the occurrence and pathogenic importance of the non-albicans species has been increasing steadily [2]. Because antifungal susceptibility is differing between the species, rapid and reliable identification of the clinical isolates can contribute to an efficient therapy of the patient [3]. The conventional identification of yeast isolates depends on biochemical properties such as assimilation and fermentation reactions and morphology [4], features which are not always stable, which are often not easy to interpret, and which may be time-consuming [5]. Biochemical identification has been standardized and (semi-)automated (e.g. Vitek-2) [6], but this approach equally suffers from the limitations of phenotypic identification in general. As a solution for those problems, several PCR-based methods have been described. Some of these approaches rely on species-specific probes [7,8] – being limited to those species
Circulation of HRSV in Belgium: From Multiple Genotype Circulation to Prolonged Circulation of Predominant Genotypes
Lieselot Houspie, Philippe Lemey, Els Keyaerts, Eva Reijmen, Valentijn Vergote, Anne Vankeerberghen, Freya Vaeyens, Hans De Beenhouwer, Marc Van Ranst
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060416
Abstract: Molecular surveillance of HRSV in Belgium for 15 consecutive seasons (1996–2011) revealed a shift from a regular 3-yearly cyclic pattern, into a yearly alternating periodicity where HRSV-B is replaced by HRSV-A. Phylogenetic analysis for HRSV-A demonstrated the stable circulation of GA2 and GA5, with GA2 being dominant over GA5 during 5 consecutive seasons (2006–2011). We also identified 2 new genotype specific amino acid mutations of the GA2 genotype (A122 and Q156) and 7 new GA5 genotype specific amino acid mutations (F102, I108, T111, I125, D161, S191 and L217). Several amino acid positions, all located in the second hypervariable region of HRSV-A were found to be under positive selection. Phylogenetic analysis of HRSV-B showed the circulation of GB12 and GB13, where GB13 represented 100% of the isolated strains in 4 out of 5 consecutive seasons (2007–2011). Amino acids under positive selection were all located in the aminoterminal hypervariable region of HRSV-B, except one amino acid located in the conserved region. The genotype distribution within the HRSV-B subgroup has evolved from a co-circulation of multiple genotypes to the circulation of a single predominant genotype. The Belgian GB13 strains circulating since 2006, all clustered under the BAIV branch and contained several branch specific amino acid substitutions. The demographic history of genotypes GA2, GA5 and GB13 demonstrated a decrease in the total GA2 and GA5 population size, coinciding with the global expansion of the GB13 population. The emergence of the GB13 genotype resulted in a newly established balance between the predominant genotypes.
Negotiated Complexity: Framing Multi-Criteria Decision Support in Environmental Health Practice  [PDF]
Hans Keune, Johan Springael, Wim De Keyser
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.31A015

The complexity we take into account when dealing with complex issues and the way we deal with that complexity is not given or self-evident, it is framed and negotiated. Based on two environmental health decision support case studies we address a set of key methodological choices, crucial in shaping the multi-criteria decision support and illuminate how they followed from transdisciplinary collaboration and negotiation: diversity tolerance, dealing with uncertainty and difference of opinion, weight of information and the epistemological divide between traditional closed and alternative open paradigms. The case studies exemplify the growing conviction amongst methodologists that, especially regarding complex issues, best methods do not exist as such: methods are chosen and tailored in practice and the quality to a large extent is dependent on the process in which methodological development is embedded. We hope to contribute to making explicit the importance of methodological decision making regarding environmental health complexity.

Counterfactual Definiteness and Bell’s Inequality  [PDF]
Karl Hess, Hans De Raedt, Kristel Michielsen
Journal of Modern Physics (JMP) , 2016, DOI: 10.4236/jmp.2016.713150
Abstract: Counterfactual definiteness must be used as at least one of the postulates or axioms that are necessary to derive Bell-type inequalities. It is considered by many to be a postulate that not only is commensurate with classical physics (as for example Einstein’s special relativity), but also separates and distinguishes classical physics from quantum mechanics. It is the purpose of this paper to show that Bell’s choice of mathematical functions and independent variables implicitly includes counterfactual definiteness. However, his particular choice of variables reduces the generality of his theory, as well as the physics of all Bell-type theories, so significantly that no meaningful comparison of these theories with actual Einstein-Podolsky-Rosen experiments can be made.
Analysis of Wigner’s Set Theoretical Proof for Bell-Type Inequalities  [PDF]
Karl Hess, Hans De Raedt, Kristel Michielsen
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.81005
Abstract: We present a detailed analysis of the set theoretical proof of Wigner for Bell type inequalities with the following result. Wigner introduced a crucial assumption that is not related to Einstein’s local realism, but instead, without justification, to the existence of certain joint probability measures for possible and actual measurement outcomes of Einstein-Podolsky-Rosen (EPR) experiments. His conclusions about Einstein’s local realism are, therefore, not applicable to EPR experiments and the contradiction of the experimental outcomes to Wigner’s results has no bearing on the validity of Einstein’s local realism.
An Ontology about Expertise Management  [PDF]
Hans de Bruin, Gabri?lle Rossing
Journal of Computer and Communications (JCC) , 2017, DOI: 10.4236/jcc.2017.51009
Abstract: An Expertise Management ontology (EMont) is presented with which human expertise is captured. EMont aims at describing and collectively finding improvements for complex situations in which people interact with often conflicting worldviews in order to achieve goals, shared or not. EMont is rooted in systems thinking, in particular Soft Systems Methodology, to be able to accommodate stakeholders’ worldviews and activities in complex situations. Its purpose is to model human activity systems, which is illustrated with the help of a complex situation. EMont forms the heart of the Expertise Management Methodology (EMM). This methodology can be regarded as a framework to build bodies of knowledge for particular domains systematically. EMM favors a research process of abduction. By studying one or more situations, generalized models are developed that explain the observed phenomenon best. The models are then taken as a starting point to conduct additional studies. This cyclic process is repeated thereby strengthening the models. EMont has been applied in several, diverse domains such as flood protection, health care and community resilience, over a period of more than four years. In our experience, EMont is a stable ontology, well-suited to capture human activities and identify widely supported solutions for complex situations, and has proven its value in practice. EMont has been implemented in Semantic Media Wiki to publish bodies of knowledge on the web.
de Wit,Hans;
Theologica Xaveriana , 2008,
Abstract: the author recalls the reception history of the small prophetic book of jonah, and in particular of its main actor, the prophet jonah. many and diverse have been the identifications proposed for the prophet jonah. in the reception history jonah has become a true metaphor to represent a vast array of figures, characters, attitudes, possibilities of being. many of these identifications reflect what bathkin called "dominant reading traditions". applying the theory of social memory (halbwachs), the author explores a new way of seeing jonah and his role in the book and asks in which measure jonah should be seen as a bearer of the social memory of the little ones, those that are sacrified for the benefit of the big empires.
Job insecurity: Review of the international literature on definitions, prevalence, antecedents and consequences
Hans De Witte
South African Journal of Industrial Psychology , 2005, DOI: 10.4102/sajip.v31i4.200
Abstract: This article reviews the literature on job insecurity. After defining the concept and its components, the prevalence of job insecurity among workers is discussed. Next, various antecedents are charted, and the consequences of job insecurity for the health and well-being of individuals and for their attitudes and behaviours towards organizations are discussed. Finally, some practical suggestions are made in order to reduce the harmful effects of insecurity, and some suggestions for future research are formulated. The focus of this review article is on studies from Europe and the U.S. As such, it aims to introduce the field of job insecurity to South African researchers. Opsomming Die artikel gee ’n oorsig van die literatuur oor werksonsekerheid. Na die defineering van die konsep en die komponente, word die voorkoms van werksonsekerheid onder werknemers bespreek. Volgende word verskeie antesedente bespreek, en die gevolge van werksonsekerheid op die gesondheid en welstand van individue, hul gesindhede en hul gedrag teenoor die organisasie bespreek. Laastens word daar ’n paar praktiese voorstelle gemaak om die skadelike gevolge van onsekerheid te verminder, asook voorstelle vir toekomstige navorsing. Die fokus van hierdie oorsig artikel is op studies in Europa and die VSA gemaak, en as sulks beoog dit om die veld van werksonsekerheid aan Suid-Afrikaanse navorsers voor te stel.
Long-term job insecurity, job satisfaction and organisational attitudes: Test of Warr’s Curvilinear Hypothesis
Hans De Witte
South African Journal of Industrial Psychology , 2005, DOI: 10.4102/sajip.v31i4.212
Abstract: Research suggests that job insecurity is an important work stressor, negatively affecting well-being and organisational attitudes and behaviours. This article concentrates on two often ignored issues in this field. First, the consequences of long-term job insecurity regarding job satisfaction, the evaluation of management and organisational attitudes are analysed. Secondly, Warr’s assumption of curvilinear associations between job insecurity and well-being is tested, and extended to the evaluation of management and organisational attitudes. The hypotheses are tested with data of 769 employees from various branches of a large European multinational company. In total, 15 reliable scales were used to test the hypotheses. The results show that 48,2% of the interviewees had worries about their long-term job security. Separate analyses of variance showed that long-term job insecurity was associated with two thirds of the scales. Long-term job insecurity was associated with lower job satisfaction, lower organisational attitudes and a lower evaluation of supervisors and management. Warr’s assumption of curvilinear associations with job insecurity was not corroborated, however. Suggestions for practice and for future research are discussed. Opsomming Navorsing stel voor dat werksonsekerheid ’n belangrike werk stressor is en dat dit welstand, organisasie gesindhede en gedrag negetief affekteer. Die artikel konsentreer op twee onderwerpe in hierdie veld wat gereeld geignoreer word. Eerstens word die gevolge van langtermyn werksonsekerheid met betrekking tot werkstevredenheid, die evaluering van bestuur en organisasiegesindhede geanaliseer. Tweedens, is Warr se aanames van kromlynige verhoudings tussen werksonsekerheid en welstand getoets, en uitgebrei tot die evaluasie van bestuur en organisasiegesindhede. Die hipotese is getoets met data van 769 werknemers van verskeie takke van ’n groot Europese multinasionale maatskappy. Daar is in totaal 15 betroubare skale gebruik om die hipotese te toets. Die resultate dui aan dat 48,2% van die persone angstig was oor hulle lang-termyn werksekuriteit. Afsonderlike analise van variansies toon dat langtermyn werkonsekerheid geassosi er was met twee derdes van die skale. Lang-termyn werkonsekerheid was geassosi er met laer van werkstevredenheid, laer organisasie gesindhede en ’n laer evaluasie van toesighouers en bestuur. Warr se aannames van kromlynige verhoudings met werksonsekerheid was nie bevestig nie. Voorstelle vir toekomstige navorsing word ook bespreek.
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