Search results for "heterogeneity"
showing 10 items of 402 documents
Exploring the relevance and extent of small airways dysfunction in asthma (ATLANTIS): baseline data from a prospective cohort study
2019
BACKGROUND: Small airways dysfunction (SAD) is well recognised in asthma, yet its role in the severity and control of asthma is unclear. This study aimed to assess which combination of biomarkers, physiological tests, and imaging markers best measure the presence and extent of SAD in patients with asthma.METHODS: In this baseline assessment of a multinational prospective cohort study (the Assessment of Small Airways Involvement in Asthma [ATLANTIS] study), we recruited participants with and without asthma (defined as Global Initiative for Asthma severity stages 1-5) from general practices, the databases of chest physicians, and advertisements at 29 centres across nine countries (Brazil, Chi…
Les pratiques pédagogiques des enseignants universitaires :
2012
In France, some studies (Boyer & Coridian, 2002; Clanet, 2001) have highlighted the heterogeneity of teaching practices at the university, especially in the first year, but don't analyze accurately the effects of this variety on the students. However, these practices are not without consequences for them (Bireaud 1990; Bellat Duru, 1995; Galinon Menelec, 1996). So it is to this reflection that is dedicated the research presented in this article. Firstly will be presented studies in France and abroad about the description of practices. The second part will focus on the effects induced by them on students. Finally, we will present an innovative viewpoint of research, on the relationship betwe…
Unmet needs and challenges in gastric cancer: The way forward
2014
AbstractAlthough the incidence of gastric cancer has fallen steadily in developed countries over the past 50years, outcomes in Western countries remain poor, primarily due to the advanced stage of the disease at presentation. While earlier diagnosis would help to improve outcomes for patients with gastric cancer, better understanding of the biology of the disease is also needed, along with advances in therapy. Indeed, progress in the treatment of gastric cancer has been limited, mainly because of its genetic complexity and heterogeneity. As a result, there is an urgent need to apply precision medicine to the management of the disease in order to ensure that individuals receive the most appr…
Determinants of macroinvertebrate diversity in headwater streams: regional and local influences
2003
Summary 1 Multiscale determinants of diversity and the relationship between regional (RSR) and local richness (LSR) have recently attracted increased attention, yet such studies on stream organisms remain scarce. We studied the relationships among RSR, β-diversity, LSR and local environmental variables in 120 headwater streams in Finland. Approximately similar-sized areas of eight drainage systems were defined as regions, and 15 stream riffles (= locality) per region were sampled. 2 RSR showed a strong positive relationship with mean LSR (R2 = 0·686), and there was no sign of curvilinearity within the observed range of RSR. RSR was also positively, although non-significantly, related to β-d…
Effect of customer heterogeneity on the relationship satisfaction–loyalty
2014
Abstract The need to study the differences among consumers due to their behavioural heterogeneity and the highly competitive consumer markets is recognized. In this paper, we analyse the potential heterogeneous shopping assessment in retail and how that experience may influence on consequent customer loyalty in a different way. The effects of satisfaction on attitudinal and behavioural loyalty and positive word of mouth are estimated by a finite-mixture structural equation model, and unobserved heterogeneity is analysed simultaneously. The results show that there are three latent segments where the strength of causal relationships differs which mean that there is an overestimation of the im…
Occupational exposure to extremely low frequency electric and magnetic fields and Alzheimer disease: a meta-analysis
2008
Background Among potential environmental risk factors for Alzheimer disease (AD), occupational exposures have received some attention, including extremely low frequency electromagnetic fields (ELF-EMF). A systematic review and meta-analysis of published epidemiological studies on this subject was carried out. Methods The search was concluded in April 2006. Bibliographic databases consulted included PubMed, EMBASE, Cochrane Library and NIOSHTIC2. Pooled estimates were obtained using random-effects meta-analysis. Sources of heterogeneity between studies were explored, as was publication bias. Results Fourteen different studies (nine case-control and five cohort studies) accomplished inclusion…
Genetic heterogeneity in the VP7 of group C rotaviruses.
2007
AbstractEvidence for a possible zoonotic role of group C rotaviruses (GCRVs) has been recently provided. To gain information on the genetic relationships between human and animal GCRVs, we sequenced the VP7 gene of 10 porcine strains detected during a large surveillance study from different outbreaks of gastroenteritis in piglets. Four GCRV strains were genetically related to the prototype GCRV porcine Cowden strain. A completely new VP7 genotype included 4 strains (344/04-7-like) that shared 92.5% to 97.0% aa identity to each other, but <83% to human GCRVs and <79% to other porcine and bovine GCRVs. A unique 4-aa insertion (SSSV or SSTI), within a variable region at the carboxy-terminus of…
Analysis of the Overdispersed Clock in the Short-Term Evolution of Hepatitis C Virus: Using the E1/E2 Gene Sequences to Infer Infection Dates in a Si…
2006
Abstract The assumption of a molecular clock for dating events from sequence information is often frustrated by the presence of heterogeneity among evolutionary rates due, among other factors, to positively selected sites. In this work, our goal is to explore methods to estimate infection dates from sequence analysis. One such method, based on site stripping for clock detection, was proposed to unravel the clocklike molecular evolution in sequences showing high variability of evolutionary rates and in the presence of positive selection. Other alternatives imply accommodating heterogeneity in evolutionary rates at various levels, without eliminating any information from the data. Here we pre…
Taste heterogeneity and latent preferences in the choice behaviour of freight transport operators
2013
In this paper we show that individual attitudes of road carriers and their latent preferences toward specific freight service attributes do play a role in determining their mode choices. Specifically, we contribute to the empirical literature on freight agents' mode choice by exploring the role of the "perceived importance" of the most relevant service dimensions in determining the attractiveness of two alternatives to "all-road" transport: logistics terminals and road-sea intermodal services. This is carried out through a revealed/stated preference experiment and a mixture of logit framework. Our results support the hypothesis that operators' attitudes towards time, punctuality and risk of…
Trophic adaptability shapes isotopic niche of the resident fish Aphanius fasciatus across lagoon habitats
2022
Abstract Coastal lagoons are characterized by high habitat heterogeneity where natural habitats coexist with artificial ones, historically set up to support human activities. Increasing anthropogenic pressure may lead to progressive degradation of the most vulnerable lagoonal habitats and the associated biological communities. One of the strictly estuarine-dependent fish species that may be affected by the degradation of lagoon habitats is the South European toothcarp Aphanius fasciatus, archetype of Mediterranean lagoon residents. Carbon and nitrogen stable isotopes were used to disentangle the influence of habitat types (natural vs artificial) and fish community (multi-trophic context) on…