Moving beyond the cost–loss ratio : economic assessment of streamflow forecasts for a risk-averse decision maker

A large effort has been made over the past 10 years to promote the operational use of probabilistic or ensemble streamflow forecasts. Numerous studies have shown that ensemble forecasts are of higher quality than deterministic ones. Many studies also conclude that decisions based on ensemble rather than deterministic forecasts lead to better decisions in the context of flood mitigation. Hence, it is believed that ensemble forecasts possess a greater economic and social value for both decision makers and the general population. However, the vast majority of, if not all, existing hydro-economic studies rely on a cost–loss ratio framework that assumes a risk-neutral decision maker. To overcome this important flaw, this study borrows from economics and evaluates the economic value of early warning flood systems using the well-known Constant Absolute Risk Aversion (CARA) utility function, which explicitly accounts for the level of risk aversion of the decision maker. This new framework allows for the full exploitation of the information related to a forecasts’ uncertainty, making it especially suited for the economic assessment of ensemble or probabilistic forecasts. Rather than comparing deterministic and ensemble forecasts, this study focuses on comparing different types of ensemble forecasts. There are multiple ways of assessing and representing forecast uncertainty. Consequently, there exist many different means of building an ensemble forecasting system for future streamflow. One such possibility is to dress deterministic forecasts using the statistics of past error forecasts. Such dressing methods are popular among operational agencies because of their simplicity and intuitiveness. Another approach is the use of ensemble meteorological forecasts for precipitation and temperature, which are then provided as inputs to one or many hydrological model(s). In this study, three concurrent ensemble streamflow forecasting systems are compared: simple statistically dressed deterministic forecasts, forecasts based on meteorological ensembles, and a variant of the latter that also includes an estimation of state variable uncertainty. This comparison takes place for the Montmorency River, a small flood-prone watershed in southern central Quebec, Canada. The assessment of forecasts is performed for lead times of 1 to 5 days, both in terms of forecasts’ quality (relative to the corresponding record of observations) and in terms of economic value, using the new proposed framework based on the CARA utility function. It is found that the economic value of a forecast for a risk-averse decision maker is closely linked to the forecast reliability in predicting the upper tail of the streamflow distribution. Hence, post-processing forecasts to avoid overforecasting could help improve both the quality and the value of forecasts

Entre la colère… et la rupture du lien social : Des personnes ayant des incapacités témoignent de leur expérience face aux carences de la protection sociale

L’article présente les résultats d’une recherche qualitative qui avait pour objectif d’identifier et de décrire les conséquences sociales sur la santé de l’inaccessibilité aux services et aux compensations financières pour les personnes ayant des incapacités et leurs proches. Cinquante-deux personnes ont été rencontrées lors d’une entrevue individuelle. L’analyse de contenu des entrevues révèle que l’inaccessibilité entraîne des conséquences négatives sur la santé physique, la santé mentale et la participation sociale. L’analyse fait également ressortir comment les personnes composent face aux carences de la protection sociale. Ces résultats sont discutés à la lumière des transformations récentes dans les pratiques de compensation au Québec.This article presents the results of a qualitative study aiming to identify and describe the social and health consequences of the inaccessibility of services and financial compensations for people with disabilities and their close relations. Fifty-two people were individually interviewed. Content analysis of the interviews reveals that inaccessibility leads to negative consequences on physical health, mental health and social participation. The analysis also revealed how people deal with inadequacies in social protection. These results are discussed in light of recent transformations in Quebec’s compensation practices

The xenotropic murine leukemia virus-related retrovirus debate continues at first international workshop

The 1st International Workshop on Xenotropic Murine Leukemia Virus-Related Retrovirus (XMRV), co-sponsored by the National Institutes of Health, The Department of Health and Human Services and Abbott Diagnostics, was convened on September 7/8, 2010 on the NIH campus, Bethesda, MD. Attracting an international audience of over 200 participants, the 2-day event combined a series of plenary talks with updates on different aspects of XMRV research, addressing basic gammaretrovirus biology, host response, association of XMRV with chronic fatigue syndrome and prostate cancer, assay development and epidemiology. The current status of XMRV research, concerns among the scientific community and suggestions for future actions are summarized in this meeting report

Femur fracture repair of a tiger cub (Panthera tigris tigris) suffering from nutritional secondary hyperparathyroidism and osteopenia

A five-month old tiger (Panthera tigris tigris) presented for an acute-onset pelvic limb lameness workup. The cub had been fed a meat-only diet. Radiology revealed severe generalised osteopenia, pathological fractures of the pelvis and proximal right femur. The history, clinical presentation and pathognomonic radiographic findings were consistent with nutritional secondary hyperparathyroidism. The cub was initially treated conservatively by dietary management (whole chicken supplemented with calcium-multivitamin powder). Fourteen day follow-up radiographs revealed increased bone density, healing pelvic fractures and callus formation around the displaced femoral fracture fragments. Despite the osteopenia, the femoral cortices were considered dense enough to allow internal fixation using a locking plate–rod combination. Fracture reduction was complicated by extensive callus formation and muscle atrophy. Follow-up radiography on day 63 revealed excellent secondary bone healing and improved bone density. The cub was discharged into the owner’s care and has reportedly made a full recovery.http://vetrecordcasereports.bmj.comhb201

Inotropic effect of nicardipine in patients with heart failure: Assessment by left ventricular end-systolic pressure-volume analysis

AbstractNicardipine, a new dihydropyridine calcium channel blocker, has been investigated for the treatment of coronary artery disease and heart failure. To assess the inotropic effect of nicardipine in humans independent of its vasodilator effect, equihypotensive doses of intravenous nitroprusside (mean infusion rate 65 ± 13 μg/min) and nicardipine (mean dose 5.2 ± 0.4 mg) were administered to 15 patients with heart failure (New York Heart Association functional classes II to IV, radionuclide left ventricular ejection fraction 0.15 ± 0.02). Left ventricular micromanometer pressure and simultaneous radionuclide left ventricular volume were obtained at baseline, during nitroprusside infusion, during a second baseline period and during nicardipine infusion.Heart rate did not change significantly with either nitroprusside or nicardipine. Mean systemic arterial pressure decreased by an average of 21 mm Hg with both drugs. A greater decrease in left ventricular end-diastolic pressure occurred with nitroprusside (27 ± 2 to 14 ± 2 mm Hg, p < 0.01) than with nicardipine (27 ± 2 to 23 ± 3 mm Hg, p < 0.05), and pulmonary capillary wedge pressure decreased significantly only with nitroprusside. Cardiac index increased from 1.8 ± 0.1 to 2.1 ± 0.1 liters/min per m2(p < 0.05) with nitroprusside and to a greater extent from 1.7 ± 0.1 to 2.4 ± 0.1 liters/min per m2(p < 0.01) with nicardipine. Left ventricular ejection fraction increased with nicardipine (0.15 ± 0.01 to 0.19 ± 0.01, p < 0.01), but not with nitroprusside.Peak positive first derivative of left ventricular pressure (dP/dt) decreased by 9% with both agents. Left ventricular pressure-volume loops were constructed for 14 patients. In 12 patients, the left ventricular end-systolic pressure-volume relation was shifted rightward with nicardipine, indicating a negative inotropic effect, with no shift in the remaining 2 patients.Thus, nicardipine has a negative inotropic effect in patients with heart failure. Despite this effect, left ventricular ejection fraction and cardiac index increased with nicardipine. This overall improvement in ventricular systolic performance was due to a reduction in afterload

Controlling a spillover pathway with the molecular cork effect

Spillover of reactants from one active site to another is important in heterogeneous catalysis and has recently been shown to enhance hydrogen storage in a variety of materials. The spillover of hydrogen is notoriously hard to detect or control. We report herein that the hydrogen spillover pathway on a Pd/Cu alloy can be controlled by reversible adsorption of a spectator molecule. Pd atoms in the Cu surface serve as hydrogen dissociation sites from which H atoms can spillover onto surrounding Cu regions. Selective adsorption of CO at these atomic Pd sites is shown to either prevent the uptake of hydrogen on, or inhibit its desorption from, the surface. In this way, the hydrogen coverage on the whole surface can be controlled by molecular adsorption at a minority site, which we term a ‘molecular cork’ effect. We show that the molecular cork effect is present during a surface catalysed hydrogenation reaction and illustrate how it can be used as a method for controlling uptake and release of hydrogen in a model storage syste

Estimation des positions d'objets 3D à partir d'une séquence d'images monoculaire

Cet article présente une méthode d'estimation des positions d'objets 3D à partir de primitives 2D extraites d'une séquence d'images monoculaire. L'estimation de la structure est ici rendue possible par l'utilisation de la modélisation de Plücker, dont l'avantage est de présenter une formulation invariante du mouvement en 2D et 3D. Cette méthode est bien adaptée à la prise en compte de tout objet que l'on peut décrire par une approximation polygonale

Letter to the editor: Pre-exposure prophylaxis for HIV in Europe: The need for resistance surveillance

__To the editor:__ In a recent paper by Hauser et al. in this journal, a prevalence of 10.8% of transmitted drugresistant viruses was reported among newly diagnosed HIV cases in Germany in 2013 and 2014. The authors conclude that genotypic resistance testing remains important for treatment as well as HIV prevention. We comment on the use of pre-exposure prophylaxis (PrEP) in relation to drug resistance in HIV infections and the need for European surveillance of drug resistance

Identification of a novel resistance (E40F) and compensatory (K43E) substitution in HIV-1 reverse transcriptase

<p>Abstract</p> <p>Background</p> <p>HIV-1 nucleoside reverse transcriptase inhibitors (NRTIs) have been used in the clinic for over twenty years. Interestingly, the complete resistance pattern to this class has not been fully elucidated. Novel mutations in RT appearing during treatment failure are still being identified. To unravel the role of two of these newly identified changes, E40F and K43E, we investigated their effect on viral drug susceptibility and replicative capacity.</p> <p>Results</p> <p>A large database (Quest Diagnostics database) was analysed to determine the associations of the E40F and K43E changes with known resistance mutations. Both amino acid changes are strongly associated with the well known NRTI-resistance mutations M41L, L210W and T215Y. In addition, a strong positive association between these changes themselves was observed. A panel of recombinant viruses was generated by site-directed mutagenesis and phenotypically analysed. To determine the effect on replication capacity, competition and <it>in vitro </it>evolution experiments were performed. Introduction of E40F results in an increase in Zidovudine resistance ranging from nine to fourteen fold depending on the RT background and at the same time confers a decrease in viral replication capacity. The K43E change does not decrease the susceptibility to Zidovudine but increases viral replication capacity, when combined with E40F, demonstrating a compensatory role for this codon change.</p> <p>Conclusion</p> <p>In conclusion, we have identified a novel resistance (E40F) and compensatory (K43E) change in HIV-1 RT. Further research is indicated to analyse the clinical importance of these changes.</p