•Accidentology of outdoor recreation and mountain sports remains underdeveloped.•Incident reporting systems in mountain sports mostly refer to single-loop learning.•Current data nonetheless enable ...researchers to unveil complex accident sequences.•Safety related events in this field are likely to benefit from double-loop learning.•Sophisticated reporting systems might enhance risk modelling.
Accidents are notoriously frequent in mountain sports, but thorough understanding of the mechanisms of accidentality remains limited by the fragmentation of sources and by mostly heterogeneous methodologies. Nonetheless, the effectiveness of prevention must rely on detailed knowledge of typical circumstances and scenarios. Rooted in the statement that an accident is never induced by a single cause but rather by a dynamic combination of factors, this paper explores the opportunities offered by a systemic analysis of experience feedbacks on accidents and close calls. The study identifies risk factors for several hundred mountaineering accident and near miss reports. In order to enhance the benefit of these descriptions and to show the interaction of a broad variety of contributing factors, it introduces graphic models. This is not an attempt to compress the unique richness of each story, but rather to create a tree structure using the concatenation of multiple testimonials, thus enabling researchers to build general lessons out of individual cases.
A majority of snow sports enthusiasts now use snowparks, even if only occasionally. Epidemiological studies highlight the high probability of accidents occurring at these facilities, compared to ...traditional pistes. We sought to understand why and how snowparks users tackle such dangers. The representations and behaviours adopted by riders were identified using a questionnaire-based survey, developed after an initial phase of qualitative research. Age and level of expertise are the two main criteria around which the specificities of snowparks users' relationship with risk are organised. With a few rare exceptions, every expert freestyler has sustained an injury of some severity. At the same time, expert freestylers engage in a process of 'denial' regarding the dangers involved in their sport. However, expert freestylers are not simply reckless. Indeed, their relationship with risk appears to be highly calculated, judging from the various behaviours they adopt to minimise the risk of an accident occurring. Helmet wearing is the only risk management behaviour that is adopted less frequently as the individual level of ability increases. Such an attitude allows experts to test their own capacity for judgement and independent thought, while also demonstrating it to others. Thus, the relationship experts have with risk is shaped to a degree by their desire to feel part of a community and stand out from the crowd. The benefits expected from flirting with danger are the greatest and the most diverse among younger individuals. For these individuals, taking risks is a quest to find themselves and their limits and thus forge an identity.
Objectives This papers aims to provide a large overview of accidents related to sporting activities in the mountain areas. The situation review presented here in results from the collection and ...cross-referencing of existing data, mainly in France but also abroad, concerning sporting accidents in the mountains. It intends to improve our knowledge of the scope of the phenomenon, victim profiles and the explanatory factors and contexts that favor accident occurrence. Actuality The supposed importance of mountain sport accidentality, sometimes the subject of rather alarmist interpretations, must be analyzed meticulously, since the implications are many, both in terms of public health, prevention and the treatment of victims. Perspectives & projects This situation review aims to get as much as possible from the existing data, while identify any shady areas that may constitute improvement areas for accidentology. Conclusion In spite of numerous initiatives, or perhaps because of the fragmentation of sources, there appears to be room for improvement regarding the study of sporting accidents in the mountains; a multitude of data exists, providing interesting framing elements, but current knowledge remains dispersed and sometimes incomplete, due in particular to heterogeneous methodologies that do not always provide an overall vision. Prevention should be based on detailed knowledge of the frequency of accidents, their circumstances and risk factors, which represent the pillars of accidentology, in the sense of the scientific study of accidents. The prevention of risks related to mountain sports requires more detailed knowledge of the accident mechanisms. Such progress will enable us to make progress in terms of preventive measures, information and practices.
En Europe, 130 personnes périssent chaque année en avalanche, essentiellement lors de la pratique de sports de montagne. Cet article se focalise sur une innovation technique destinée à éviter ...l’ensevelissement lorsqu’une personne est emportée par une coulée : l’airbag d’avalanche. L’objectif est de réaliser un état des connaissances sur ce nouvel équipement, en privilégiant l’étude de son efficacité.
Le protocole de revue systématique mis en oeuvre, vérifiable et reproductible, donne accès aux données de recherche publiées ces vingt dernières années (1996–2016).
Dix-sept publications spécifiquement consacrées à la question ont été recensées. Une première période (1996–2002) est marquée par la mise en oeuvre d’expérimentations relativement fragiles (en termes de conditions comme d’échantillons), conduisant à des conclusions hâtives et flatteuses pour les fabricants d’airbags, notamment en termes de survie potentielle des victimes équipées (alors représentées par des mannequins). Bénéficiant d’informations fiabilisées sur les accidents d’avalanche impliquant des personnes équipées d’airbags, les publications postérieures à 2002, plus rigoureuses sur le plan de la méthode, fournissent des résultats plus précis qui confirment l’efficacité des airbags, tout en la relativisant sur plusieurs plans : diminution du « taux de survie » constaté, évocation croissante des situations et contextes particuliers pouvant altérer l’efficacité du dispositif (mise en avant d’effets pervers), précautions accrues dans l’interprétation des données.
Cette mise au point semble d’autant plus nécessaire que les chiffres avancés par les producteurs et les médias spécialisés constituent la principale influence poussant à investir dans un airbag. Au-delà de l’affinement progressif des études centrées sur l’efficacité des airbags, il reste à investiguer, parallèlement, l’influence de la possession d’un airbag sur le processus décisionnel sur le terrain.
In Europe, 130 people die every year in avalanches, mostly while practicing mountain sports. This paper focuses on a technical innovation aiming to avoid burial when a person is caught in an avalanche: the avalanche airbag. We undertook a literature review focused on the study of the effectiveness of such device.
A systematic review protocol has been implemented. It is reproducible and gave access to 17 publications dealing with this specific topic during the last twenty years (1996–2016).
A first period (1996–2002) is characterized by the implementation of relatively fragile experiments (in terms of conditions as well as samples), leading to hasty and flattering conclusions for airbag manufacturers, especially in terms of survival rates of the equipped victims (then represented by mannequins). Benefiting from reliable information on avalanche accidents involving people equipped with airbags, post-2002 publications, much more rigorous in terms of methods, provide more accurate results that both confirm the effectiveness of airbags, and relativize it on several levels: a decrease in the “survival rate”, a growing evocation of particular situations and contexts that could alter the effectiveness of the system, and increased precautions in the interpretation of data.
This synthesis seems all the more necessary as the figures put forward by the producers and the specialized media constitute the main influencing force to invest in an airbag. Beyond the gradual refining of studies centering on the effectiveness of airbags, the influence of the possession of an airbag on the decision-making process on the field remains to investigate.
A reference material designed for the determination of natural radionuclides in solid samples (glass pellets) is described and the results of certification are presented. The material has been ...certified for 7 natural radionuclides (
40
K,
226
Ra,
228
Ra,
228
Th,
232
Th,
235
U and
238
U). An information value is given for
210
Pb. Radon (
222
Rn) emanation experiments showed results comparable within participating laboratories, however, the number of data and precision was too low to carry out a certification process. The reference material may be used for quality management of analytical laboratories engaged in the high-sensitive analysis of radionuclides in the construction materials of detectors placed in ultra low background underground laboratories.
Density functional molecular dynamics simulations have been carried out to understand the finite temperature behavior of Au19 and Au20 clusters. Au20 has been reported to be a unique molecule having ...tetrahedral geometry, a large HOMO−LUMO energy gap, and an atomic packing similar to that of the bulk gold (Li, J.; et al. Science 2003, 299, 864). Our results show that the geometry of Au19 is exactly identical with that of Au20 with one missing corner atom (called a vacancy). Surprisingly, our calculated heat capacities for this nearly identical pair of gold clusters exhibit dramatic differences. Au20 undergoes a clear and distinct solid-like to liquid-like transition with a sharp peak in the heat capacity curve around 770 K. On the other hand, Au19 has a broad and flat heat capacity curve with continuous melting transition. This continuous melting transition turns out to be a consequence of a process involving a series of atomic rearrangements along the surface to fill in the missing corner atom. This results in a restricted diffusive motion of atoms along the surface of Au19 between 650 to 900 K during which the shape of the ground state geometry is retained. In contrast, the tetrahedral structure of Au20 is destroyed around 800 K, and the cluster is clearly in a liquid-like state above 1000 K. Thus, this work clearly demonstrates that (i) the gold clusters exhibit size sensitive variations in the heat capacity curves and (ii) the broad and continuous melting transition in a cluster, a feature that has so far been attributed to the disorder or absence of symmetry in the system, can also be a consequence of a defect (absence of a cap atom) in the structure.
The chemistry and biology of nitroxide compounds Soule, Benjamin P.; Hyodo, Fuminori; Matsumoto, Ken-ichiro ...
Free radical biology & medicine,
06/2007, Letnik:
42, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Cyclic nitroxides are a diverse group of stable free radicals that have unique antioxidant properties. Because of their ability to interact with free radicals, they have been used for many years as ...biophysical tools. During the past 15–20 years, however, many interesting biochemical interactions have been discovered and harnessed for therapeutic applications. Biologically relevant effects of nitroxides have been described, including their ability to degrade superoxide and peroxide, inhibit Fenton reactions, and undergo radical–radical recombination. Cellular studies defined the activity of nitroxides in vitro. By modifying oxidative stress and altering the redox status of tissues, nitroxides have been found to interact with and alter many metabolic processes. These interactions can be exploited for therapeutic and research use, including protection against ionizing radiation, as probes in functional magnetic resonance imaging, cancer prevention and treatment, control of hypertension and weight, and protection from damage resulting from ischemia/reperfusion injury. Although much remains to be done, many applications have been well studied and some are currently being tested in clinical trials. The therapeutic and research uses of nitroxide compounds are reviewed here with a focus on the progress from initial development to modern trials.
Abstract The full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of $$^{100}$$ 100 Mo to the ground state of $$^{100}$$ 100 Ru, ...$$T_{1/2} = \left 6.81 \pm 0.01\,\left( \text{ stat }\right) ^{+0.38}_{-0.40}\,\left( \text{ syst }\right) \right \times 10^{18}$$ T1/2=6.81±0.01stat-0.40+0.38syst×1018 year. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of $$5\times 10^5$$ 5×105 events and a signal-to-background ratio of $$\sim $$ ∼ 80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limits on Majoron emitting neutrinoless double beta decay modes with spectral indices of $$\mathrm{n}=2,3,7$$ n=2,3,7 , as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained.
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