164 research outputs found
L’impact du drainage agricole souterrain sur la morphologie des petits cours d’eau dans la région de Cookshire, Québec
Le drainage agricole souterrain a des effets sur l'hydrologie des bassins versants, ce qui, selon toute vraisemblance, se répercute sur la morphologie des cours d'eau. Cette note montre que, pour une même superficie de drainage, les petits cours d'eau des bassins versants où il y a drainage souterrain sont plus larges et de plus grande dimension que ceux sans drainage souterrain. Bien que le lien entre cet effet et les changements du régime hydrologique n'ait pu être établi directement, les résultats laissent croire à une augmentation des débits de pointe par suite de l'implantation des drains souterrains.Land drainage induces hydrological changes which should effect stream channel morphology. This paper shows that, for a similar drainage area, small stream channels of watersheds with land drainage are larger in width and size than those without land drainage. Despite the fact that a direct link between this morphological effect and changes in the hydrological regime has not been established, these results suggest an increase in peak discharge following the introduction of land drainage
La trajectoire et les besoins des détenus provinciaux souffrant de troubles concomitants de santé mentale et de toxicomanie
Au Québec, un nombre grandissant de personnes souffrent de troubles concomitants de santé mentale et de toxicomanie. Impossible, toutefois, d'en connaître la proportion exacte étant donné l'absence de statistiques officielles à ce sujet. Les intervenants oeuvrant sur le terrain affirment néanmoins qu'à l'heure actuelle, la situation est particulièrement préoccupante à l'intérieur des Établissements de détention provinciaux. En effet, les personnes souffrant de troubles concomitants sont particulièrement touchées par la judiciarisation de leurs problématiques et constituent une population spécialement vulnérable une fois incarcérées.Au moyen de deux études de cas, cette recherche a exploré la trajectoire et les besoins des détenus provinciaux souffrant à la fois de problèmes de santé mentale et de toxicomanie. De l'analyse des données recueillies ressortent notamment des lacunes au niveau du dépistage des problématiques, de la formation des intervenants et de la prise en charge de la clientèle. De plus, il semble qu'un plan d'intervention sociale bien défini soit nettement plus profitable à cette clientèle que l'unique prescription de médicaments ou encore l'incarcération. Ces divers éléments ont été abordés au cours de cette recherche afin d'aboutir à plusieurs recommandations visant à améliorer la qualité des services offerts aux personnes judiciarisées souffrant de troubles concomitants de santé mentale et de toxicomanie
Évaluation des performances mécaniques de stratifiés carbone-époxy préformés à l'aide de la couture "one-sides"
Le moulage par infusion sous vide se prête bien à la mise en forme de pièces en composites de formes complexes ou de grandes tailles, mais il y a un besoin criant d’automatiser le drapage des renforts secs pour que ce procédé rencontre les standards de qualité et d’efficacité de l’industrie aéronautique. Le préformage automatisé des renforts secs à l’aide de la couture « one-sided stitching » (OSS�) est une des techniques de préformage pouvant répondre à ce besoin. Toutefois, la couture peut altérer les performances mécaniques du stratifié et doit donc être utilisée judicieusement.
L’objectif de ce mémoire consiste à évaluer les effets de la couture OSS� sur les performances mécaniques de divers stratifiés afin de formuler des recommandations pour en faire une utilisation idéale pour le préformage d’un panneau raidi. Pour ce faire, les caractéristiques et propriétés de stratifiés cousus sont comparées à celles de stratifiés référentiels (non cousus) à chacune des trois étapes de la démarche expérimentale.
Durant la première étape, les effets de trois paramètres de mise en forme (c.-à-d. le pas de couture, la stratégie de moulage et l’orientation des coutures par rapport à la direction de chargement) sur les propriétés d’un stratifié quasi isotrope sont étudiés à l’aide d’une série d’essais physiques et mécaniques afin de sélectionner les paramètres de mise en forme optimaux pour la suite des travaux. Les résultats montrent que pour minimiser la surépaisseur et l’augmentation de la masse surfacique causées par la couture sans détériorer la résistance à la compression avec trou et la résistance à la compression après impact, le pas de couture doit être maximisé, la préforme doit être retournée entre le montage de couture et celui d’infusion sous vide de manière à ce que le dessus de la préforme soit placé contre le moule et finalement, les lignes coutures doivent être transversales à la direction de chargement.
Durant la seconde étape, les effets de la couture OSS� sur les propriétés mécaniques statiques de trois types de stratifiés sont étudiés. Les résultats des essais de tension, de compression et de flexion montrent que la couture provoque une diminution de la résistance intralaminaire, une augmentation de la résistance interlaminaire et une augmentation globale de la rigidité.
Durant la troisième étape, les effets de la couture OSS� sur la tolérance à l’endommagement de trois types de stratifiés sont étudiés. Les résultats des essais de compression avec trou, d’impact, de compression après impact et de propagation d’une fissure interlaminaire (Mode I) montrent que la couture augmente légèrement la résistance en présence de dommages, augmente l’énergie absorbée par le stratifié durant un impact et augmente drastiquement la résistance à la propagation d’une fissure interlaminaire.
En se basant sur les divers effets de la couture OSS observés, des recommandations en ce qui a trait à l’usage idéal de la couture pour le préformage d’un panneau raidi sont établies. Il est notamment recommandé de (1) minimiser la densité de couture si le panneau est fortement sollicité dans le plan, (2) maximiser la densité de couture si le panneau est susceptible de subir un impact et (3) coudre le voile et la semelle du raidisseur le plus près de la nouille possible pour réduire le risque de propagation d’une fissure interlaminaire
Experience of Health Leadership in Partnering With University-Based Researchers in Canada – A Call to “Re-imagine” Research
Background: Emerging evidence that meaningful relationships with knowledge users are a key predictor of research use has led to promotion of partnership approaches to health research. However, little is known about health system experiences of collaborations with university-based researchers, particularly with research partnerships in the area of health system design and health service organization. The purpose of the study was to explore the experience and perspectives of senior health managers in health service organizations, with health organization-university research partnerships. Methods: In-depth, semi-structured interviews (n = 25) were conducted with senior health personnel across Canada to explore their perspectives on health system research; experiences with health organization-university research partnerships; challenges to partnership research; and suggested actions for improving engagement with knowledge users and promoting research utilization. Participants, recruited from organizations with regional responsibilities, were responsible for system-wide planning and support functions. Results: Research is often experienced as unhelpful or irrelevant to decision-making by many within the system. Research, quality improvement (QI) and evaluation are often viewed as separate activities and coordinated by different responsibility areas. Perspectives of senior managers on barriers to partnership differed from those identified in the literature: organizational stress and restructuring, and limitations in readiness of researchers to work in the fast-paced healthcare environment, were identified as major barriers. Although the need for strong executive leadership was emphasized, “multi-system action” is needed for effective partnerships. Conclusion: Common approaches to research and knowledge translation are often not appropriate for addressing issues of health service design and health services organization. Nor is the research community providing expertise to many important activities that the healthcare system is taking to improve health services. A radical rethinking of how we prepare health service researchers; position research within the health system; and fund research activities and infrastructure is needed if the potential benefits of research are to be achieved. Lack of response to health system needs may contribute to research and ‘evidence-informed’ practice being further marginalized from healthcare operations. Interventions to address barriers must respond to the perspectives and experience of health leadership
Moderate to severe acute pain disturbs motor cortex intracortical inhibition and facilitation in orthopedic trauma patients : a TMS study
Objective
Primary motor (M1) cortical excitability alterations are involved in the development and maintenance of chronic pain. Less is known about M1-cortical excitability implications in the acute phase of an orthopedic trauma. This study aims to assess acute M1-cortical excitability in patients with an isolated upper limb fracture (IULF) in relation to pain intensity.
Methods
Eighty-four (56 IULF patients <14 days post-trauma and 28 healthy controls). IULF patients were divided into two subgroups according to pain intensity (mild versus moderate to severe pain). A single transcranial magnetic stimulation (TMS) session was performed over M1 to compare groups on resting motor threshold (rMT), short-intracortical inhibition (SICI), intracortical facilitation (ICF), and long-interval cortical inhibition (LICI).
Results
Reduced SICI and ICF were found in IULF patients with moderate to severe pain, whereas mild pain was not associated with M1 alterations. Age, sex, and time since the accident had no influence on TMS measures.
Discussion
These findings show altered M1 in the context of acute moderate to severe pain, suggesting early signs of altered GABAergic inhibitory and glutamatergic facilitatory activities
Antarctic ice sheet paleo-constraint database
We present a database of observational constraints on past Antarctic Ice Sheet changes during the last glacial cycle intended to consolidate the observations that represent our understanding of past Antarctic changes, for state-space estimation, and paleo-model calibrations. The database is a major expansion of the initial work of Briggs and Tarasov (2013). It includes new data types and multi-tier data quality assessment. The updated constraint database “AntICE2” consists of observations of past grounded and floating ice sheet extent, past ice thickness, past relative sea level, borehole temperature profiles, and present-day bedrock displacement rates. In addition to paleo-observations, the present-day ice sheet geometry and surface ice velocities are incorporated to constrain the present-day ice sheet configuration. The method by which the data is curated using explicitly defined criteria is detailed. Moreover, the observational uncertainties are specified. The methodology by which the constraint database can be applied to evaluate a given ice sheet reconstruction is discussed. The implementation of the “AntICE2” database for Antarctic Ice Sheet model calibrations will improve Antarctic Ice Sheet predictions during past warm and cold periods and yield more robust paleo model spin ups for forecasting future ice sheet changes
Fish introductions and light modulate food web fluxes in tropical streams: a whole-ecosystem experimental approach
Decades of ecological study have demonstrated the importance of top-down and bottom-up controls on food webs, yet few studies within this context have quantified the magnitude of energy and material fluxes at the whole-ecosystem scale. We examined top-down and bottom-up effects on food web fluxes using a field experiment that manipulated the presence of a consumer, the Trinidadian guppy Poecilia reticulata, and the production of basal resources by thinning the riparian forest canopy to increase incident light. To gauge the effects of these reach-scale manipulations on food web fluxes, we used a nitrogen (N-15) stable isotope tracer to compare basal resource treatments (thinned canopy vs. control) and consumer treatments (guppy introduction vs. control). The thinned canopy stream had higher primary production than the natural canopy control, leading to increased N fluxes to invertebrates that feed on benthic biofilms (grazers), fine benthic organic matter (collector-gatherers), and organic particles suspended in the water column (filter feeders). Stream reaches with guppies also had higher primary productivity and higher N fluxes to grazers and filter feeders. In contrast, N fluxes to collector-gatherers were reduced in guppy introduction reaches relative to upstream controls. N fluxes to leaf-shredding invertebrates, predatory invertebrates, and the other fish species present (Hart\u27s killifish, Anablepsoides hartii) did not differ across light or guppy treatments, suggesting that effects on detritus-based linkages and upper trophic levels were not as strong. Effect sizes of guppy and canopy treatments on N flux rates were similar for most taxa, though guppy effects were the strongest for filter feeding invertebrates while canopy effects were the strongest for collector-gatherer invertebrates. Combined, these results extend previous knowledge about top-down and bottom-up controls on ecosystems by providing experimental, reach-scale evidence that both pathways can act simultaneously and have equally strong influence on nutrient fluxes from inorganic pools through primary consumers
Long-term hydroxyurea in combination with didanosine and stavudine for the treatment of HIV-1 infection
Objective and methods: In 1998 we reported on a randomized comparison between stavudine plus didanosine plus placebo versus stavudine plus didanosine plus hydroxyurea (HU), in patients with a CD4 count of 200±500 3 10 6 cells/l. After 3 months, the HU group had a higher proportion of patients with viral load , 200 3 10 6 cells/l. At the end of the 3 months blinded period, patients in the placebo group had the option to add HU if their viral load remained . 200 3 10 6 cells/l. We report results after 24 months. Results: Seventy-two patients were randomized to the HU arm, and a further 30 elected to add HU after 12 weeks. Twenty-four months after the start of the trial, only 25% of the 72 patients originally randomized to HU, and 20% of the 30 who added HU after week 12, were still taking it. The reasons for stopping HU were: lack of ef®cacy (45%), adverse events (37%) and patient or physician preference (18%). Side effects were more frequent in the didanosine/stavudine/HU group than in the didanosine/stavudine group: neuropathy (35 versus 15%, P , 0.02), fatigue (22 versus 7%, P , 0.01), and nausea or vomiting (26 versus 9%, P ,0.01). Of those who had discontinued HU, 73% were taking three drugs including a protease inhibitor. Patients who had started HU were compared with similar patients who had started protease inhibitors in the Swiss cohort. The probability of stopping HU was higher than the probability of stopping nel®navir or indinavir, and similar to the probability of stopping ritonavir. Conclusion: HU increased the antiviral effect of stavudine plus didanosine. However, side effects were more frequent, and after 24 months the majority of patients had switched to protease inhibitor regimens
Evidence that Proteasome-Dependent Degradation of the Retinoblastoma Protein in Cells Lacking A-Type Lamins Occurs Independently of Gankyrin and MDM2
A-type lamins, predominantly lamins A and C, are nuclear intermediate filaments believed to act as scaffolds for assembly of transcription factors. Lamin A/C is necessary for the retinoblastoma protein (pRB) stabilization through unknown mechanism(s). Two oncoproteins, gankyrin and MDM2, are known to promote pRB degradation in other contexts. Consequently, we tested the hypothesis that gankyrin and/or MDM2 are required for enhanced pRB degradation in Lmna-/- fibroblasts. Principal Findings. To determine if gankyrin promotes pRB destabilization in the absence of lamin A/C, we first analyzed its protein levels in Lmna-/- fibroblasts. Both gankyrin mRNA levels and protein levels are increased in these cells, leading us to further investigate its role in pRB degradation. Consistent with prior reports, overexpression of gankyrin in Lmna+/+ cells destabilizes pRB. This decrease is functionally significant, since gankyrin overexpressing cells are resistant to p16(ink4a)-mediated cell cycle arrest. These findings suggest that lamin A-mediated degradation of pRB would be gankyrin-dependent. However, effective RNAi-enforced reduction of gankyrin expression in Lmna-/- cells was insufficient to restore pRB stability. To test the importance of MDM2, we disrupted the MDM2-pRB interaction by transfecting Lmna-/- cells with p14(arf). p14(arf) expression was also insufficient to stabilize pRB or confer cell cycle arrest, suggesting that MDM2 also does not mediate pRB degradation in Lmna-/- cells.Our findings suggest that pRB degradation in Lmna-/- cells occurs by gankyrin and MDM2-independent mechanisms, leading us to propose the existence of a third proteasome-dependent pathway for pRB degradation. Two findings from this study also increase the likelihood that lamin A/C functions as a tumor suppressor. First, protein levels of the oncoprotein gankyrin are elevated in Lmna-/- fibroblasts. Second, Lmna-/- cells are refractory to p14(arf)-mediated cell cycle arrest, as was previously shown with p16(ink4a). Potential roles of lamin A/C in the suppression of tumorigenesis are discussed
Exome sequencing identifies germline variants in DIS3 in familial multiple myeloma
[Excerpt] Multiple myeloma (MM) is the third most common hematological malignancy, after Non-Hodgkin Lymphoma and Leukemia. MM is generally preceded by Monoclonal Gammopathy of Undetermined Significance (MGUS) [1], and epidemiological studies have identified older age, male gender, family history, and MGUS as risk factors for developing MM [2].
The somatic mutational landscape of sporadic MM has been increasingly investigated, aiming to identify recurrent genetic events involved in myelomagenesis. Whole exome and whole genome sequencing studies have shown that MM is a genetically heterogeneous disease that evolves through accumulation of both clonal and subclonal driver mutations [3] and identified recurrently somatically mutated genes, including KRAS, NRAS, FAM46C, TP53, DIS3, BRAF, TRAF3, CYLD, RB1 and PRDM1 [3,4,5].
Despite the fact that family-based studies have provided data consistent with an inherited genetic susceptibility to MM compatible with Mendelian transmission [6], the molecular basis of inherited MM predisposition is only partly understood. Genome-Wide Association (GWAS) studies have identified and validated 23 loci significantly associated with an increased risk of developing MM that explain ~16% of heritability [7] and only a subset of familial cases are thought to have a polygenic background [8]. Recent studies have identified rare germline variants predisposing to MM in KDM1A [9], ARID1A and USP45 [10], and the implementation of next-generation sequencing technology will allow the characterization of more such rare variants. [...]French National Cancer Institute (INCA) and the Fondation Française pour la Recherche contre le Myélome et les Gammapathies (FFMRG), the Intergroupe Francophone du Myélome (IFM), NCI R01 NCI CA167824 and a generous donation from Matthew Bell. This work was supported in part through the computational resources and staff expertise provided by Scientific Computing at the Icahn School of Medicine at Mount Sinai. Research reported in this paper was supported by the Office of Research Infrastructure of the National Institutes of Health under award number S10OD018522. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors thank the Association des Malades du Myélome Multiple (AF3M) for their continued support and participation. Where authors are identified as personnel of the International Agency for Research on Cancer / World Health Organization, the authors alone are responsible for the views expressed in this article and they do not necessarily represent the decisions, policy or views of the International Agency for Research on Cancer / World Health Organizatio
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