221 research outputs found

    Influence of Forest Management on the Species Richness and Composition of Wood-inhabiting Basidiomycetes in Swiss Forests

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    In order to investigate the diversity of wood-inhabiting aphyllophoroid basidiomycetes in Swiss forests, 86 plots of 50m 2 were established. They harboured a total of 3339 samples of woody debris, classified according to three categories (coarse, fine, and very fine woody debris), yielding 238 species of wood-inhabiting fungi. The selected sites cover the main forest types of Switzerland and various degrees of management intensity. A multiple linear regression analysis showed that substrate variation, i.e. differences in the quality of dead wood, including volume, age, degree of decomposition and host tree species, are the most important factors influencing diversity of wood-inhabiting fungi. In addition, a Principle Coordinate Analysis highlighted differences in the fungal communities in the different forest types. The greatest fungal species richness is found on thermophilic deciduous tree and woody shrub species. Fine and very fine woody debris, even present in intensively managed forests, often serve as important refuges for many species. Forests with a recent management intervention were found to be either species poor or species rich. Possible reasons for these differences may lay in forest size and landscape fragmentation, the distance to the nearest species pool or microclimatic factors. In Switzerland intensively managed forests harbour significantly less wood-inhabiting, aphyllophoroid fungi than non-managed or extensively managed forests. This is the case in both deciduous forests and in conifer forests. However, occasionally intensively managed forest will also harbour rare and endangered specie

    Diversity and ecology of wood-inhabiting aphyllophoroid basidiomycetes on fallen woody debris in various forest types in Switzerland

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    This study on the ecology of aphyllophoroid wood-inhabiting basidiomycetes in Switzerland showed a remarkably high species diversity of both saprophytes and mycorrhiza-forming species. Phlebiella vaga, a saprophytic species, and Amphinema byssoides, a mycorrhizal symbiont, were the two most abundant species. A total of 3339 samples of fungal fruitbodies in 86 plots distributed all over Switzerland belonged to 238 species. The five main biogeographical regions of Switzerland showed different pattern of fungal species richness: while the Plateau at lower altitudes was found to be rather rich, the Northern Alps and Central Alps, with the highest amount of forests cover, yielded less species. Although the Southern Alps exhibited the lowest species richness, this region harbours a specific species set. These findings encourage for further studies in Central Europe, where many species of aphyllophoroid wood-inhabiting basidiomycetes seem to be highly under-investigate

    Learning cortical representations through perturbed and adversarial dreaming.

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    Humans and other animals learn to extract general concepts from sensory experience without extensive teaching. This ability is thought to be facilitated by offline states like sleep where previous experiences are systemically replayed. However, the characteristic creative nature of dreams suggests that learning semantic representations may go beyond merely replaying previous experiences. We support this hypothesis by implementing a cortical architecture inspired by generative adversarial networks (GANs). Learning in our model is organized across three different global brain states mimicking wakefulness, NREM and REM sleep, optimizing different, but complementary objective functions. We train the model on standard datasets of natural images and evaluate the quality of the learned representations. Our results suggest that generating new, virtual sensory inputs via adversarial dreaming during REM sleep is essential for extracting semantic concepts, while replaying episodic memories via perturbed dreaming during NREM sleep improves the robustness of latent representations. The model provides a new computational perspective on sleep states, memory replay and dreams and suggests a cortical implementation of GANs

    Rapid Colonization with Methicillin-Resistant Coagulase-Negative Staphylococci After Surgery

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    Background: Antimicrobial resistance may compromise the efficacy of antibiotic prophylaxis before surgery. The aim of this study was to measure susceptibility and clonal distribution of coagulase-negative staphylococci (CoNS) colonizing the skin around the surgery access site before and after the procedure. Methods: From March to September 2004, a series of 140 patients undergoing elective major abdominal surgery were screened for CoNS colonization at admission and 5days after surgery. All isolates were tested for antibiotic susceptibility and genotyped by pulsed-field gel electrophoresis (PFGE). Results: Colonization rates with CoNS at admission and after surgery were 85% and 55%, respectively. The methicillin-resistant CoNS rate increased from 20% at admission to 47% after surgery (P=0.001). The PFGE pattern after surgery revealed more patients colonized with identical clones: 8/140 patients (8/119 strains) and 26/140 patients (26/77 strains), respectively (P<0.001). Conclusions: Our results suggest rapid recolonization of disinfected skin by resistant nosocomial CoNS. Larger studies, preferably among orthopedic or cardiovascular patients, are required to clarify whether standard antibiotic prophylaxis with first- or second-generation cephalosporins for CoNS infections may be compromised if the patient requires an additional intervention 5days or more after the initial surger

    Ecological determinants of fungal diversity on dead wood in European forests

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    International audienceThe fine-scale ecological determinants for wood-inhabiting aphyllophoroid basidiomycetes were investigated with statistical analyses of the occurrence of fruit bodies on woody debris collected in Switzerland and Ukraine. Three substrate descriptors were considered: diameter, degree of decomposition and host tree species. By means of Multiple Regression Trees, thresholds in the response of fungal communities to these local environmental descriptors were detected. Three classes for diameter, as well as for degree of decomposition were thus delimited. They revealed the importance of very small sizes, which were not reported in the literature so far: the relevant diameter class limits were about 0.72 cm and 1.35 cm. Within the host tree species, a clear distinction between coniferous and broadleaf species was found. The next splits followed rather climatic determinants of tree distribution than taxonomical entities such as families or genera. The fidelity of the 59 fungal species to diameter classes, decomposition classes and host tree species was measured by the Dufrêne-Legendre index and only significant responses after permutation tests were retained. This brought new insights on the ecology of many wood-inhabiting aphyllophoroid basidiomycetes. Redundancy Analysis was applied to investigate the response of fungal species to diameter and degree of decomposition of woody debris from the most common host tree species, Fagus sylvatica. This direct gradient analysis made it possible to reconstruct the succession of fungal species along the wood decomposition process

    Pour des services de santé suisses durables dans les limites planétaires : feuille de route de l’Académie Suisse des Sciences Médicales (ASSM) = Umweltbewusste Gesundheitsversorgung in der Schweiz : Positionspapier der Schweizerischen Akademie der Medizinischen Wissenschaften (SAMW)

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    L’ASSM a publié en 2019 une feuille de route sur la (non)-durabilité du système de santé suisse, soulignant notamment que la médecine d’aujourd’hui repose sur un paradigme de progrès illimité, créant et étant confrontée à des attentes irréalistes, alors que les ressources financières et humaines sur lesquelles elle repose sont limitées. La (non)-durabilité environnementale des systèmes de santé n’y est que peu abordée. Pourtant, au vu des urgences écologiques et climatiques, et de retombées attendues sur la santé des populations, il semble cohérent d’étendre les recommandations de la feuille de route de 2019 aux considérations environnementales. En effet, alors que des gains importants en termes d’espérance de vie et de santé globale ont été obtenus ces dernières décennies, ces progrès risquent d’être compromis par le dépassement des limites planétaires, et notamment par le dérèglement du climat et l’érosion de la biodiversité. Par ailleurs, les services de santé, responsables d’environ 5 % des émissions de gaz à effet de serre, devront non seulement s’adapter aux retombées sanitaires découlant des dégradations environnementales (canicules, maladies infectieuses émergentes), mais aussi avoir pour ambition de questionner leur modèle de fonctionnement. Cela s’avère en effet prépondérant afin d’accompagner les transformations sociétales nécessaires pour inscrire le fonctionnement des sociétés humaines dans les limites planétaires. Cette feuille de route, élaborée en collaboration avec une soixantaine d’expert.e.s en santé et durabilité, représente une première étape visant à penser des services de santé durables en Suisse. Les sept propositions formulées doivent permettre de guider les acteurs.trices de la santé, à tous les niveaux (politique, clinique, hospitalier, ambulatoire), dans l’élaboration d’actions concrètes et adaptées à leur contexte de pratique

    Des pistes pour des services de santé durables

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    Les dégradations environnementales auxquelles le système de santé contribue de façon non négligeable ont un impact croissant sur la santé humaine. Des services de santé durables sont dès lors des services qui respectent les limites planétaires. L’Académie Suisse des Sciences Médicales (ASSM) a choisi ce focus environnemental pour sa nouvelle feuille de route

    Supporting students in the transition to postgraduate taught study in STEM subjects

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    While there has been a wide range of studies examining the transition of undergraduate and postgraduate research students, there are few which concentrate on the experiences of postgraduate taught (PGT) students. This is unfortunate, because PGT students have pressing needs for support: since taught masters courses last for usually one academic year, postgraduate students are asked to adapt and succeed at a far faster rate than undergraduates, who take four years in Scotland to complete an honours degree. PGT students are a minority group amongst the university population, with e.g. more than three times as many undergraduates enrolled at the University of Glasgow than postgraduates. Furthermore, international students represent a high proportion of PGT students. To better understand the needs of PGT students and therefore improve the quality of their education, we need to understand their experiences and challenges as they transition through their course. This paper presents a study focused on PGT students in STEM subjects at the University of Glasgow. Feedback from students in the College of Science and Engineering was gathered using a multi-methodological approach. Surveys, one-to-one interviews and a workshop were utilised to investigate students’ perceptions of support received from staff and services. This data was linked to student academic confidence, social confidence, and overall satisfaction with their experience at the university. Data were gathered at three points in the year to evaluate whether perceptions change as students progress through their course. This data from surveys and interviews was used to direct a workshop, which discussed potential solutions to issues raised. Better online resources were identified as key to feeling prepared before the commencement of a PGT course, and better communication with lecturers and peers was important to the success and satisfaction of students, particularly after beginning PGT study

    The use of classification and regression trees to predict the likelihood of seasonal influenza

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    Background Individual signs and symptoms are of limited value for the diagnosis of influenza. Objective To develop a decision tree for the diagnosis of influenza based on a classification and regression tree (CART) analysis. Methods Data from two previous similar cohort studies were assembled into a single dataset. The data were randomly divided into a development set (70%) and a validation set (30%). We used CART analysis to develop three models that maximize the number of patients who do not require diagnostic testing prior to treatment decisions. The validation set was used to evaluate overfitting of the model to the training set. Results Model 1 has seven terminal nodes based on temperature, the onset of symptoms and the presence of chills, cough and myalgia. Model 2 was a simpler tree with only two splits based on temperature and the presence of chills. Model 3 was developed with temperature as a dichotomous variable (≥38°C) and had only two splits based on the presence of fever and myalgia. The area under the receiver operating characteristic curves (AUROCC) for the development and validation sets, respectively, were 0.82 and 0.80 for Model 1, 0.75 and 0.76 for Model 2 and 0.76 and 0.77 for Model 3. Model 2 classified 67% of patients in the validation group into a high- or low-risk group compared with only 38% for Model 1 and 54% for Model 3. Conclusions A simple decision tree (Model 2) classified two-thirds of patients as low or high risk and had an AUROCC of 0.76. After further validation in an independent population, this CART model could support clinical decision making regarding influenza, with low-risk patients requiring no further evaluation for influenza and high-risk patients being candidates for empiric symptomatic or drug therap
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