156 research outputs found

    Quand les élèves deviennent des lycanthropes... :: conception d’une activité utilisant les Loups-Garous deThiercelieux en lien avec les mathématiques

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    Ce travail a pour objectif d’investiguer l’utilité du jeu en classe comme milieu didactique, dans un contexte scolaire où le jeu est encore souvent vu comme un moment récréatif, et non pas comme un moyen de faire apprendre les élèves. Dans une démarche d’ingénierie didactique, le jeu des Loups- Garous de Thiercelieux a été mis en place en classe avec des élèves de 8ème Harmos et modifié, afin de l’utiliser en lien avec le thème de la proportionnalité en mathématiques. Un objectif de ce travail est de situer la pertinence du jeu dans les apprentissages, et en particulier d’examiner l’impact de l’utilisation du jeu sur l’engagement et la motivation des élèves, mais également sur la relation au savoir que les élèves peuvent développer en utilisant le jeu. Au travers de concepts tels que le triangle didactique, l’importance du milieu dans les apprentissages ou encore les sources motivationnelles, une mise en lumière de l’importance du jeu dans le milieu scolaire a été tentée

    Plant community structure determines primary productivity in shallow, eutrophic lakes

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    Regime shifts are commonly associated with the loss of submerged macrophytes in shallow lakes; yet, the effects of this on whole-lake primary productivity remain poorly understood. This study compares the annual gross primary production (GPP) of two shallow, eutrophic lakes with different plant community structures but similar nutrient concentrations. Daily GPP rates were substantially higher in the lake containing submerged macrophytes (586 ± 23 g C m−2 year−1) than in the lake featuring only phytoplankton and periphyton (408 ± 23 g C m−2 year−1; P \u3c 0.0001). Comparing lake-centre diel oxygen curves to compartmental estimates of GPP confirmed that single-site oxygen curves may provide unreliable estimates of whole-lake GPP. The discrepancy between approaches was greatest in the macrophyte-dominated lake during the summer, with a high proportion of GPP occurring in the littoral zone. Our empirical results were used to construct a simple conceptual model relating GPP to nutrient availability for these alternative ecological regimes. This model predicted that lakes featuring submerged macrophytes may commonly support higher rates of GPP than phytoplankton-dominated lakes, but only within a moderate range of nutrient availability (total phosphorus ranging from 30 to 100 μg L−1) and with mean lake depths shallower than 3 or 4 m. We conclude that shallow lakes with a submerged macrophyte–epiphyton complex may frequently support a higher annual primary production than comparable lakes that contain only phytoplankton and periphyton. We thus suggest that a regime shift involving the loss of submerged macrophytes may decrease the primary productivity of many lakes, with potential consequences for the entire food webs of these ecosystems

    Heteroduplex analysis of T-cell receptor γ gene rearrangement as an adjuvant diagnostic tool in skin biopsies for erythroderma

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    Erythroderma, defined as red skin covering most of the body surface often accompanied or followed by exfoliation, is the clinical manifestation of at least six different underlying etiologies with allergic or irritant contact dermatitis, atopic/asteotic dermatitis, pityriasis rubra pilaris (PRP), psoriasis, and seborrheic dermatitis accounting for the majority of cases. Approximately 10% of cases are due to adverse drug reactions with roughly another 10% due to cutaneous T-cell lymphoma (CTCL), predominantly mycosis fungoides, or leukemia. It is clear from multiple studies that the clinical diagnosis of the underlying entity is often difficult, as these diseases can present in a very similar fashion. A skin biopsy is usually employed in this setting as a diagnostic tool. However, the histopathologic diagnosis of the underlying cause is complicated by the subtlety of the distinguishing histologic features. In this situation, an ancillary technique demonstrating the presence of a monoclonal T-cell proliferation could help to rule in or out CTCL in cases that clinically and histopathologically do not allow a definitive diagnosis. Methods: We retrospectively studied 25 biopsies from sixteen patients who presented to the Stanford Dermatology Clinic with erythroderma. We examined the specimens morphologically and analyzed the gamma chain of the T-cell receptor (TCR- γ) by polymerase chain reaction (PCR) followed by heteroduplex analysis for clonality. We then correlated the results of our PCR and heteroduplex analyses with the patients’ clinical outcomes. Results: Four biopsies, from three patients, contained clonal TCR-γ rearrangements; the four biopsies, all of which were equivocal histologically, correlated to diagnoses of mycosis fungoides (MF) or SÉzary syndrome (SS). Twenty-one biopsies contained polyclonal T-cell populations. Eighteen of these biopsies represent patients with inflammatory dermatoses. Three of these biopsies, all of which were taken from a single patient, correlate to a diagnosis of MF. Conclusion: TCR-γ PCR heteroduplex analysis seems to represent an important adjuvant diagnostic tool that, used in conjunction with histopathology and clinical history, could help to clarify the underlying etiology of erythroderma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72286/1/j.1600-0560.2001.280703.x.pd

    Convective mixing and high littoral primary production can establish systematic errors in lake diel oxygen curves in shallow, eutrophic lakes

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    The diel (24-h) oxygen (O2) curves approach has become a popular method for analyzing gross primary production (GPP) and ecosystem respiration (ER) rates in aquatic systems. Despite the simplicity of this approach, there remain aspects of the calculation and interpretation of diel O2 curves which may skew results, with potentially large implications for estimates of metabolic rates. One common problem in lakes is the occurrence of unexpected changes in O2concentrations (for instance, increasing overnight O2 concentrations). Such changes have typically been ascribed to the random mixing of pockets of O2. It has thus been suggested that negative GPP or positive ER values should be included in calculations, on the assumption that under- and overestimates should occur with equal frequency, and thus cancel each other out. Our data from a shallow, eutrophic lake provided a high share of negative GPP values. We argue that these may have been the result of elevated littoral productivity coupled with convective currents produced by consistent differences in the heating or cooling of littoral and offshore waters. Such phenomena might be common in small, sheltered lakes where the role of mixing by wind is diminished. We conclude that a failure to account for consistent metabolic gradients and periodic convective mixing may lead to a chronic underestimation of metabolic rates in lakes when using the diel O2 curves method

    Stay on the ball! An interaction pattern approach to the engineering of motivation

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    Abstract: This paper introduces an interaction pattern approach to "engineer" motivation. Its goal is to provide concrete ideas (in the form of patterns) on how to design software that motivates its users to stay on a task. The paper presents an example of a motivating pattern, the Task Status Display (TSD), and its empirical validation. Preliminary results support its motivational effect, thereby lending support to the general notion of building motivation into interactive products for the workplace

    Oleaginous yeasts respond differently to carbon sources present in lignocellulose hydrolysate

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    Background Microbial oils, generated from lignocellulosic material, have great potential as renewable and sustainable alternatives to fossil-based fuels and chemicals. By unravelling the diversity of lipid accumulation physiology in different oleaginous yeasts grown on the various carbon sources present in lignocellulose hydrolysate (LH), new targets for optimisation of lipid accumulation can be identified. Monitoring lipid formation over time is essential for understanding lipid accumulation physiology. This study investigated lipid accumulation in a variety of oleaginous ascomycetous and basidiomycetous strains grown in glucose and xylose and followed lipid formation kinetics of selected strains in wheat straw hydrolysate (WSH). Results Twenty-nine oleaginous yeast strains were tested for their ability to utilise glucose and xylose, the main sugars present in WSH. Evaluation of sugar consumption and lipid accumulation revealed marked differences in xylose utilisation capacity between the yeast strains, even between those belonging to the same species. Five different promising strains, belonging to the species Lipomyces starkeyi, Rhodotorula glutinis, Rhodotorula babjevae and Rhodotorula toruloides, were grown on undiluted wheat straw hydrolysate and lipid accumulation was followed over time, using Fourier transform-infrared (FTIR) spectroscopy. All five strains were able to grow on undiluted WSH and to accumulate lipids, but to different extents and with different productivities. R. babjevae DVBPG 8058 was the best-performing strain, accumulating 64.8% of cell dry weight (CDW) as lipids. It reached a culture density of 28 g/L CDW in batch cultivation, resulting in a lipid content of 18.1 g/L and yield of 0.24 g lipids per g carbon source. This strain formed lipids from the major carbon sources in hydrolysate, glucose, acetate and xylose. R. glutinis CBS 2367 also consumed these carbon sources, but when assimilating xylose it consumed intracellular lipids simultaneously. Rhodotorula strains contained a higher proportion of polyunsaturated fatty acids than the two tested Lipomyces starkeyi strains. Conclusions There is considerable metabolic diversity among oleaginous yeasts, even between closely related species and strains, especially when converting xylose to biomass and lipids. Monitoring the kinetics of lipid accumulation and identifying the molecular basis of this diversity are keys to selecting suitable strains for high lipid production from lignocellulose

    Mapping the landscape of lung cancer breath analysis: A scoping review (ELCABA)

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    Lung cancer is the leading cause of cancer death worldwide due to its late-stage detection. Lung cancer screening, including low-dose computed tomography (low-dose CT), provides an initial clinical solution. Nevertheless, further innovations and refinements would help to alleviate remaining limitations. The non-invasive, gentle, and fast nature of breath analysis (BA) makes this technology highly attractive to supplement low-dose CT for an improved screening algorithm. However, BA has not taken hold in everyday clinical practice. One reason might be the heterogeneity and variety of BA methods. This scoping review is a comprehensive summary of study designs, breath analytical methods, and suggested biomarkers in lung cancer. Furthermore, this synthesis provides a framework with core outcomes for future studies in lung cancer BA. This work supports future research for evidence synthesis, meta-analysis, and translation into clinical routine workflows. Keywords: Biomarker; Breath; Detection; Lung cancer; Scoping review; Screenin

    Euphrasia Eye Drops in Preterm Neonates With Ocular Discharge: A Randomized Double-Blind Placebo-Controlled Trial

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    Aim: To investigate whether the early administration of Euphrasia eye drops® in preterm neonates presenting with ocular discharge fosters the resolution of the ocular discharge and reduces the need for topical antibiotic therapy, as compared to placebo. Methods: We conducted a randomized double-blind placebo-controlled trial at the University Children's Hospital Bern, Switzerland. Preterm neonates with white, yellow, or green ocular discharge were included. Infants were randomly assigned (1:1) to the Euphrasia arm (Euphrasia eye drops®, Weleda AG, Arlesheim) or the placebo arm (NaCl 0.9%). Euphrasia or placebo was administrated at a dose of one drop in each eye four times a day over a period of 96 h. The primary outcome was the treatment success, defined as no ocular discharge at 96 h and no use of topical antibiotic therapy during the 96-h intervention. Results: A total of 114 neonates were screened and 84 were randomized. Among neonates in the Euphrasia arm, 22 (55.0%) achieved our primary outcome compared to 21 (51.2%) in the placebo arm (p = 0.85). In the Euphrasia arm, time to resolution of reddening tended to fall within the shorter bracket of 24 to 48 h (24 (92.3%) vs. 12 (80.0%) in the placebo arm, p = 0.34) and relapse or first signs of reddening during the 96-h intervention tended to be lower [3 (7.9%) eyes vs. 8 (18.2%) eyes in the placebo arm, p = 0.17]. Tearing at 96 h tended to be lower in the Euphrasia arm [5 (12.8%) eyes in the Euphrasia arm vs. 12 (27.3%) eyes in the placebo arm, p = 0.10]. Discussion: Euphrasia did not significantly improve treatment success, defined as no ocular discharge at 96 h and no use of topical antibiotic therapy during the 96-h intervention. However, results suggest that Euphrasia may be of benefit for symptoms such as reddening and tearing, and thus improve the comfort of patients. Trial Registration: The trial is registered at the US National Institutes of Health (ClinicalTrials.gov) NCT04122300 and at the portal for human research in Switzerland SNCTP000003490. Keywords: Euphrasia drops; complementary medicine; congenital nasolacrimal duct obstruction; ocular discharge; preterm neonate
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