Limnologie du Nord de l'Île d'Ellesmere

Les lacs et les fjords du nord de l’Île d’Ellesmere, au Nunavut, renferment des écosystèmes uniques qui dépendent de la glace pour le maintien de leur structure. Certains de ces « cryo-écosystèmes » sont stratifiés en permanence, formés d’une couche d’eau douce flottant sur une couche d’eau de mer. Ces stratifications sont entre autres dues à la limitation du brassage par le vent en raison de la présence d’un couvert de glace permanent. Les travaux présentés ici ont comme objectif principal d’évaluer la diversité limnologique et biologique des lacs côtiers du nord de l’Île d’Ellesmere afin de mieux comprendre leur réponse aux changements environnementaux et climatiques à deux échelles temporelles : leurs variations à long terme à l’échelle de l’Holocène et leur réponse récente au climat dans le cours des dernières décennies. D’abord, les différents environnements sont présentés comme faisant partie d’une chronoséquence limnologique d’évolution du paysage à l’échelle de l’Holocène, à partir d’un fjord stratifié jusqu’à un lac d’eau douce en passant par un lac méromictique stratifié en permanence. Les facteurs de changements des environnements sont ensuite explorés en observant leur réponse aux changements climatiques récents. Puis, une étude de l’écologie microbienne de ces lacs et de ces fjords est présentée, insistant sur la dominance des picocyanobactéries dans leurs eaux de surface, en contraste avec les eaux de l’Océan Arctique, d’où sont issus ces milieux aquatiques. Une analyse moléculaire de la diversité génétique des cyanobactéries a été également effectuée et celle-ci met en valeur les grandes tolérances des cyanobactéries. Enfin, les communautés de zooplancton présentes dans ces environnements sont étudiées, afin d’élargir le portrait de ces environnements, et d’établir un point de base pour les études futures des transformations causées par les changements climatiques. Cette région du globe est très sensible aux changements climatiques, et les propriétés de ces écosystèmes tels que décrits ici sont un point de départ pour l’évaluation des changements futurs.The lakes and fjords of northern Ellesmere Island, Nunavut, harbor unique ice-dependant ecosystems. Some of these “cryo-ecosystems” are permanently stratified, with a freshwater layer overlying sea water. This extreme stratification is due in part to the limitation of wind-derived mixing because of the presence of a perennial ice-cover. The main objective of the work presented here was to evaluate the limnological and biological diversity of coastal lakes of northern Ellesmere Island in order to better understand their response to environmental change at two timescales: their long term variations over the Holocene and their recent responses to climate over the last few decades. The environments were shown to form a limnological chronosequence that reflected landscape evolution at the Holocene timescale, from stratified fjords to freshwater lakes, via phases in which the water bodies were stratified, meromictic lakes with different degrees of wind-induced mixing depending on the duration of ice cover, from perennial to seasonally open water conditions under warmer climates. Each of these phases is represented today in northern Nunavut. The sensitivity of these stratified ecosystems to environmental change at shorter timescales was then explored, by observing the limnological impacts of current climate change in the Ellesmere Island region. As a first step towards addressing the question of biodiversity and microbial community structure in these ecosystems, a molecular ecology analysis of the lake and fjord biota was made, and underscored the dominance of picocyanobacteria in their surface waters, in contrast with the low abundance of these microbes in the Arctic Ocean, from which those aquatic environments originate. The DNA analysis of the picocyanobacteria implied broad tolerances among these organisms, with the same genetic groups found in a great variety of environments, both on a local and a planetary scale. Finally, a study was undertaken of the zooplankton communities in a lake and fjord of northern Ellesmere Island to develop a broader portrait of these unique ecosystems, and to establish a baseline for future studies of the ongoing impacts of climate changes. This region of the globe is highly sensitive to climate change, and the properties of these ecosystems as discovered and described here are likely to undergo great transformations in the years to come

Imaging strategies for detection of urgent conditions in patients with acute abdominal pain: diagnostic accuracy study

Objective To identify an optimal imaging strategy for the accurate detection of urgent conditions in patients with acute abdominal pain

‘Obuntu Bulamu’ – Development and Testing of an Indigenous Intervention for Disability Inclusion in Uganda

There is need to learn from indigenous knowledge and concepts when studying disability and inclusion in resource-constrained settings. We describe the development and testing of the ‘Obuntu bulamu’ intervention, a peer-to-peer support disability inclusion intervention, starting from indigenous interpretations of belonging and humanity. ‘Obuntu bulamu’ is an accepted and consistent behaviour that signifies a shared set of values that promote well-being, togetherness, and unity. The intervention was co-created and tested by a team of children, parents, teachers, disability rehabilitation workers, and academics in Uganda. It consists of training sessions, peer support meetings, and activities for children, parents, and teachers around the themes ‘peer support’, ‘disability’, and ‘belonging’. Through qualitative participatory methods the feasibility and acceptability of the intervention was evaluated with 64 children, 64 parents, and 33 teachers in 10 communities in Wakiso district, Central Uganda

Approach for Predicting Production Scenarios Focused on Cross Impact Analysis

AbstractOne of the most consistent challenges in business is anticipating what the future holds and what impact it may have on current production systems. The scenario technique is a well-established method for developing and forecasting multiple future development paths for companies. However, this method is mostly employed to develop and to support strategic long-term decisions. The core idea of the approach introduced in this paper is to convey the future impact of today's decisions on production systems to employees involved in production planning processes. With the help of immersive visualization, performed in virtual reality (VR) systems, planning participants can perceive how the factory must adapt to fit future demands.In this paper, the focus is on the fourth phase of the scenario technique – so called scenario development – and, in particular, the cross impact analysis. With this methodology, the interrelations, or cross impacts of the different basic elements are determined. The cross impact analysis results serve as a basis for the development of a standardized tool that can be used to create probable production scenarios out of given production systems. This standardized tool will facilitate the usage of the scenario technique for factory planning projects, as it focuses the immense diversity of future uncertainties companies are faced with on the factory level

Ketogenic diet as a glycine lowering therapy in nonketotic hyperglycinemia and impact on brain glycine levels

BACKGROUND: Nonketotic hyperglycinemia (NKH) is a severe neurometabolic disorder characterized by increased glycine levels. Current glycine reduction therapy uses high doses of sodium benzoate. The ketogenic diet (KD) may represent an alternative method of glycine reduction. AIM: We aimed to assess clinical and biochemical effects of two glycine reduction strategies: high dose benzoate versus KD with low dose benzoate. METHODS: Six infants with NKH were first treated with high dose benzoate therapy to achieve target plasma glycine levels, and then switched to KD with low dose benzoate. They were evaluated as clinically indicated by physical examination, electroencephalogram, plasma and cerebral spinal fluid amino acid levels. Brain glycine levels were monitored by magnetic resonance spectroscopy (MRS). RESULTS: Average plasma glycine levels were significantly lower with KD compared to benzoate monotherapy by on average 28%. Two infants underwent comparative assessments of brain glycine levels via serial MRS. A 30% reduction of brain glycine levels was observed in the basal ganglia and a 50% reduction in the white matter, which remained elevated above normal, and was equivalent between the KD and high dose benzoate therapies. CSF analysis obtained while participants remained on the KD showed a decrease in glycine, serine and threonine levels, reflecting their gluconeogenetic usage. Clinically, half the patients had seizure reduction on KD, otherwise the clinical impact was variable. CONCLUSION: KD is an effective glycine reduction method in NKH, and may provide a more consistent reduction in plasma glycine levels than high-dose benzoate therapy. Both high-dose benzoate therapy and KD equally reduced but did not normalize brain glycine levels even in the setting of low-normal plasma glycine

Recognition and localization of relevant human behavior in videos, SPIE,

ABSTRACT Ground surveillance is normally performed by human assets, since it requires visual intelligence. However, especially for military operations, this can be dangerous and is very resource intensive. Therefore, unmanned autonomous visualintelligence systems are desired. In this paper, we present an improved system that can recognize actions of a human and interactions between multiple humans. Central to the new system is our agent-based architecture. The system is trained on thousands of videos and evaluated on realistic persistent surveillance data in the DARPA Mind's Eye program, with hours of videos of challenging scenes. The results show that our system is able to track the people, detect and localize events, and discriminate between different behaviors, and it performs 3.4 times better than our previous system

Digital Signal Processing

Contains an introduction and reports on fourteen research projects.National Science Foundation FellowshipNational Science Foundation (Grant ECS84-07285)U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)Sanders Associates, Inc.U.S. Air Force - Office of Scientific Research (Contract F19628-85-K-0028)Advanced Television Research ProgramAmoco Foundation FellowshipHertz Foundation Fellowshi

Digital Signal Processing

Contains an introduction and reports on fifteen research projects.U.S. Navy - Office of Naval Research (Contract N00O14-81-K-0742)U.S. Navy - Office of Naval Research (Contract N00014-77-C-0266)National Science Foundation (Grant ECS80-07102)National Science Foundation (Grant ECS84-07285)Amoco Foundation FellowshipSanders Associates, Inc.Advanced Television Research ProgramM.I.T. Vinton Hayes FellowshipHertz Foundation Fellowshi

A comparison of the Accuracy of Ultrasound and Computed Tomography in common diagnoses causing acute abdominal pain

Head-to-head comparison of ultrasound and CT accuracy in common diagnoses causing acute abdominal pain. Consecutive patients with abdominal pain for > 2 h and <5 days referred for imaging underwent both US and CT by different radiologists/radiological residents. An expert panel assigned a final diagnosis. Ultrasound and CT sensitivity and predictive values were calculated for frequent final diagnoses. Effect of patient characteristics and observer experience on ultrasound sensitivity was studied. Frequent final diagnoses in the 1,021 patients (mean age 47; 55% female) were appendicitis (284; 28%), diverticulitis (118; 12%) and cholecystitis (52; 5%). The sensitivity of CT in detecting appendicitis and diverticulitis was significantly higher than that of ultrasound: 94% versus 76% (p <0.01) and 81% versus 61% (p = 0.048), respectively. For cholecystitis, the sensitivity of both was 73% (p = 1.00). Positive predictive values did not differ significantly between ultrasound and CT for these conditions. Ultrasound sensitivity in detecting appendicitis and diverticulitis was not significantly negatively affected by patient characteristics or reader experience. CT misses fewer cases than ultrasound, but both ultrasound and CT can reliably detect common diagnoses causing acute abdominal pain. Ultrasound sensitivity was largely not influenced by patient characteristics and reader experience

Digital Signal Processing

Contains an introduction and reports on twenty research projects.National Science Foundation (Grant ECS 84-07285)U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)National Science Foundation FellowshipSanders Associates, Inc.U.S. Air Force - Office of Scientific Research (Contract F19628-85-K-0028)Canada, Bell Northern Research ScholarshipCanada, Fonds pour la Formation de Chercheurs et l'Aide a la Recherche Postgraduate FellowshipCanada, Natural Science and Engineering Research Council Postgraduate FellowshipU.S. Navy - Office of Naval Research (Contract N00014-81-K-0472)Fanny and John Hertz Foundation FellowshipCenter for Advanced Television StudiesAmoco Foundation FellowshipU.S. Air Force - Office of Scientific Research (Contract F19628-85-K-0028