432 research outputs found
Contrer la violence subie par les enfants? — Entrevue avec Claude Bouchard, Mona Comeau, Marie-Paule Lafleur et Gérald McNeeley
Can one detect small-scale turbulence from standard meteorological radiosondes?
International audienceIt has been recently proposed by Clayson and Kantha (2008) to evaluate the climatology of atmospheric turbulence through the detection of overturns in the free at mosphere by applying a Thorpe analysis on relatively lowy vertical resolution (LR) profiles from standard radiosoundings. Since then, several studies based on this idea have been published. However, the impact of instrumental noise on the detection of turbulent layers was completely ig- nored in these works. The present study aims to evaluate the feasibility of overturns detection from radiosoundings. For this purpose, we analyzed data of two field campaigns dur- ing which high-resolution (HR) soundings (10-20 cm) were performed simultaneously with standard LR soundings. We used the raw data of standard meteorological radiosondes, the vertical resolution ranging from 5 to 9 m. A Thorpe analysis was applied to both LR and HR po- tential temperature profiles. A denoising procedure was first applied in order to reduce the probability of occurrence of artificial overturns, i.e. potential temperature inversions due to instrumental noise only. We then compared the empirical probability density functions (pdf) of the sizes of the selected overturns from LR and HR profiles. From HR profiles measured in the troposphere, the sizes of the detected overturns range from 4 to ∼1000 m. The shape of the size pdf of overturns is found to sharply decrease with increasing scales. From LR profiles, the smallest size of de- tected overturns is ∼32 m, a similar decrease in the shape of the pdf of sizes being observed. These results suggest that overturns, resulting either from small-scale turbulence or from instabilities, can indeed be detected from meteoro- logical radiosonde measurements in the troposphere and in the stratosphere as well. However they are rather rare as they belong to the tail of the size distribution of overturns: they only represent the 7 % largest events in the troposphere, and 4 % in the stratosphere
On ordinal utility, cardinal utility, and random utility
Though the Random Utility Model (RUM) was conceived
entirely in terms of ordinal utility, the apparatus throughwhich it is widely practised exhibits properties of
cardinal utility. The adoption of cardinal utility as a
working operation of ordinal is perfectly valid, provided
interpretations drawn from that operation remain faithful
to ordinal utility. The paper considers whether the latterrequirement holds true for several measurements commonly
derived from RUM. In particular it is found that
measurements of consumer surplus change may depart from
ordinal utility, and exploit the cardinality inherent in
the practical apparatus.
The Ethiopian Field Epidemiology and Laboratory Training Program: strengthening public health systems and building human resource capacity
The Ethiopian Field Epidemiology and Laboratory Training Program (EFELTP) is a comprehensive two-year competency-based training and service program designed to build sustainable public health expertise and capacity. Established in 2009, the program is a partnership between the Ethiopian Federal Ministry of Health, the Ethiopian Health and Nutrition Research Institute, Addis Ababa University School of Public Health, the Ethiopian Public Health Association and the US Centers of Disease Control and Prevention. Residents of the program spend about 25% of their time undergoing didactic training and the 75% in the field working at program field bases established with the MOH and Regional Health Bureaus investigating disease outbreaks, improving disease surveillance, responding to public health emergencies, using health data to make recommendations and undertaking other field Epidemiology related activities on setting health policy. Residents from the first 2 cohorts of the program have conducted more than 42 outbreaks investigations, 27analyses of surveillance data, evaluations of 11 surveillance systems, had28oral and poster presentation abstracts accepted at 10 scientific conferences and submitted 8 manuscripts of which 2are already published. The EFELTP has provided valuable opportunities to improve epidemiology and laboratory capacity building in Ethiopia. While the program is relatively young, positive and significant impacts are assisting the country better detect and respond to epidemics and address diseases of major public health significance
High Stakes Decision Making: Normative, Descriptive and Prescriptive Considerations
This paper reviews the state of the art of research on individual decision-making in high-stakes, low-probability settings. A central theme of the discussion is that optimally resolving high-stakes decisions poses a formidable challenge not only to naïve decision makers, but also to users of more sophisticated tools such as decision analysis.. Such problems are difficult to resolve because precise information about probabilities is not available, and the dynamics of the decision are complex. When faced with such problems, naïve decision-makers fall prey to a wide range of potentially harmful biases, such as not recognizing a high-stakes problem, ignoring the information about probabilities that does exist, and responding to complexity by accepting the status quo. We offer an agenda for future research focusing on how the process and outcomes of high-stakes decision making might be improved
On quantum coding for ensembles of mixed states
We consider the problem of optimal asymptotically faithful compression for
ensembles of mixed quantum states. Although the optimal rate is unknown, we
prove upper and lower bounds and describe a series of illustrative examples of
compression of mixed states. We also discuss a classical analogue of the
problem.Comment: 23 pages, LaTe
Trends in measles incidence and measles vaccination coverage in Nigeria, 2008-2018
INTRODUCTION: All WHO regions have set measles elimination objective for 2020. To address the specific needs of achieving measles elimination, Nigeria is using a strategy focusing on improving vaccination coverage with the first routine dose of (monovalent) measles (MCV1) at 9 months, providing measles vaccine through supplemental immunization activities (children 9-59 months), and intensified measles case-based surveillance system. METHODS: We reviewed measles immunization coverage from population-based surveys conducted in 2010, 2013 and 2017-18. Additionally, we analyzed measles case-based surveillance reports from 2008-2018 to determine annual, regional and age-specific incidence rates. FINDINGS: Survey results indicated low MCV1 coverage (54.0% in 2018); with lower coverage in the North (mean 45.5%). Of the 153,097 confirmed cases reported over the studied period, 85.5% (130,871) were from the North. Moreover, 70.8% (108,310) of the confirmed cases were unvaccinated. Annual measles incidence varied from a high of 320.39 per 1,000,000 population in 2013 to a low of 9.80 per 1,000,000 in 2009. The incidence rate is higher among the 9-11 months (524.0 per million) and 12-59 months (376.0 per million). Between 2008 and 2018, the incidence rate had showed geographical variation, with higher incidence in the North (70.6 per million) compare to the South (17.8 per million). CONCLUSION: The aim of this study was to provide a descriptive analysis of measles vaccine coverage and incidence in Nigeria from 2008 to 2018 to assess country progress towards measles elimination. Although the total numbers of confirmed measles cases had decreased over the time period, measles routine coverage remains sub-optimal, and the incidence rates are critically high. The high burden of measles in the North highlight the need for region-specific interventions. The measles program relies heavily on polio resources. As the polio program winds down, strong commitments will be required to achieve elimination goals
Unfamiliar Territory: Emerging Themes for Ecological Drought Research and Management
Novel forms of drought are emerging globally, due to climate change, shifting teleconnection patterns, expanding human water use, and a history of human influence on the environment that increases the probability of transformational ecological impacts. These costly ecological impacts cascade to human communities, and understanding this changing drought landscape is one of today\u27s grand challenges. By using a modified horizon-scanning approach that integrated scientists, managers, and decision-makers, we identified the emerging issues in ecological drought that represent key challenges to timely and effective responses. Here we review the themes that most urgently need attention, including novel drought conditions, the potential for transformational drought impacts, and the need for anticipatory drought management. This horizon scan and review provides a roadmap to facilitate the research and management innovations that will support forward-looking, co-developed approaches to reduce the risk of drought to our socio-ecological systems during the 21st century. We used a modified horizon-scanning approach that brought together scientists, managers, and decision-makers to identify the emerging issues around the ecological impacts from drought that represent key challenges to effective response. We found three broad themes within ecological drought that need attention, including novel drought conditions, transformational drought impacts, and anticipatory drought management. This horizon scan and integrated review provides a roadmap to inspire the needed research and management innovations to reduce the risk of 21st century droughts
Testing for regularity and stochastic transitivity using the structural parameter of nested logit
We introduce regularity and stochastic transitivity as necessary and well-behaved conditions respectively, for the consistency of discrete choice preferences with the Random Utility Model (RUM). For the specific case of a three-alternative nested logit (NL) model, we synthesise these conditions in the form of a simple two-part test, and reconcile this test with the conventional zero-one bounds on the structural (‘log sum’) parameter within this model, i.e. 0 0. On the other hand, we show that neither regularity nor stochastic transitivity constrain the upper bound at one. Therefore, if the conventional zero-one bounds are imposed in model estimation, preferences which violate regularity and/or stochastic transitivity may either go undetected (if the ‘true’ structural parameter is less than zero) and/or be unknowingly admitted (if the ‘true’ lower bound is greater than zero), and preferences which comply with regularity and stochastic transitivity may be excluded (if the ‘true’ upper bound is greater than one). Against this background, we show that imposition of the zero-one bounds may compromise model fit, inferences of willingness-to-pay, and forecasts of choice behaviour. Finally, we show that where the ‘true’ structural parameter is negative (thereby violating RUM – at least when choosing the ‘best’ alternative), positive starting values for the structural parameter in estimation may prevent the exposure of regularity and stochastic transitivity failures
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