Pulmonary artery pressure and cardiac function in children and adolescents after rapid ascent to 3,450 m.

High-altitude destinations are visited by increasing numbers of children and adolescents. High-altitude hypoxia triggers pulmonary hypertension that in turn may have adverse effects on cardiac function and may induce life-threatening high-altitude pulmonary edema (HAPE), but there are limited data in this young population. We, therefore, assessed in 118 nonacclimatized healthy children and adolescents (mean ± SD; age: 11 ± 2 yr) the effects of rapid ascent to high altitude on pulmonary artery pressure and right and left ventricular function by echocardiography. Pulmonary artery pressure was estimated by measuring the systolic right ventricular to right atrial pressure gradient. The echocardiography was performed at low altitude and 40 h after rapid ascent to 3,450 m. Pulmonary artery pressure was more than twofold higher at high than at low altitude (35 ± 11 vs. 16 ± 3 mmHg; P < 0.0001), and there existed a wide variability of pulmonary artery pressure at high altitude with an estimated upper 95% limit of 52 mmHg. Moreover, pulmonary artery pressure and its altitude-induced increase were inversely related to age, resulting in an almost twofold larger increase in the 6- to 9- than in the 14- to 16-yr-old participants (24 ± 12 vs. 13 ± 8 mmHg; P = 0.004). Even in children with the most severe altitude-induced pulmonary hypertension, right ventricular systolic function did not decrease, but increased, and none of the children developed HAPE. HAPE appears to be a rare event in this young population after rapid ascent to this altitude at which major tourist destinations are located.

Major influencing factors of indoor radon concentrations in Switzerland.

PURPOSE: In Switzerland, nationwide large-scale radon surveys have been conducted since the early 1980s to establish the distribution of indoor radon concentrations (IRC). The aim of this work was to study the factors influencing IRC in Switzerland using univariate analyses that take into account biases caused by spatial irregularities of sampling. METHODS: About 212,000 IRC measurements carried out in more than 136,000 dwellings were available for this study. A probability map to assess risk of exceeding an IRC of 300 Bq/m(3) was produced using basic geostatistical techniques. Univariate analyses of IRC for different variables, namely the type of radon detector, various building characteristics such as foundation type, year of construction and building type, as well as the altitude, the average outdoor temperature during measurement and the lithology, were performed comparing 95% confidence intervals among classes of each variable. Furthermore, a map showing the spatial aggregation of the number of measurements was generated for each class of variable in order to assess biases due to spatially irregular sampling. RESULTS: IRC measurements carried out with electret detectors were 35% higher than measurements performed with track detectors. Regarding building characteristics, the IRC of apartments are significantly lower than individual houses. Furthermore, buildings with concrete foundations have the lowest IRC. A significant decrease in IRC was found in buildings constructed after 1900 and again after 1970. Moreover, IRC decreases at higher outdoor temperatures. There is also a tendency to have higher IRC with altitude. Regarding lithology, carbonate rock in the Jura Mountains produces significantly higher IRC, almost by a factor of 2, than carbonate rock in the Alps. Sedimentary rock and sediment produce the lowest IRC while carbonate rock from the Jura Mountains and igneous rock produce the highest IRC. Potential biases due to spatially unbalanced sampling of measurements were identified for several influencing factors. CONCLUSIONS: Significant associations were found between IRC and all variables under study. However, we showed that the spatial distribution of samples strongly affected the relevance of those associations. Therefore, future methods to estimate local radon hazards should take the multidimensionality of the process of IRC into account.

Spiritual Kinship, Political Mobilization and Social Cooperation: a Swiss Alpine valley in the Eighteenth and Nineteenth Centuries

In this chapter I will present some observations and results about Ritual Kinship and political mobilization of popular groups in an Alpine valley: the Val de Bagnes, in the Swiss canton of Valais, - a mountain valley, well known today thanks to the tourist station of Verbier - where we can rely on excellent sources about local families. This region presents a particular political situation, because the 11 major villages of the valley form only one commune, which includes the whole valley.¦There are two major reasons to choose the Val de Bagnes for our inquiry on kinship and social networks in a rural society:¦A. The existence of sharp political and social conflicts during the 18th and the 19th centuries;¦B. The existence of almost systematic genealogical data between 1700 and 1900. (Casanova, Gard, Perrenoud 2005-08)¦The 18th century was characterized by the struggle of an important part of the community of Bagnes against the feudal lord, the abbot of St-Maurice. The culminating point was a local upheaval in 1745 in Le Châble, during which the abbot was forced to sign several documents in accordance with the wishes of the rebels (Guzzi-Heeb 2007). In the 19th century feudal lordship was abolished, but now the struggle confronted a liberal-radical faction and the conservative majority in the commune.¦The starting point of my presentation focuses on this question: which role did spiritual kinship play in the political mobilization of popular groups and in the organization of competing factions? This question allows us to shed light on some utilizations and meanings of spiritual kinship in the local society. Was spiritual kinship a significant instrument for economic cooperation? Or was it a channel for privileged social contacts and transactions?

How to Measure Scope Variables when no Metrics Exist : Application to Landscape Quality Measurement and Hedonic Price Evaluation

Landscape is an example of a non-market good where no metrics exist to measure its quality. The paper proposes an original methodology to nevertheless estimate scope variables in those circumstances, allowing then to better test if people's willingnesstopay for such good is sensitive to the scope. The methodology is based on techniques developed in the context of multicriteria decision analysis. It is applied to assess the quality of the landscape of several Swiss alpine resorts. This assessment is then used as an explanatory variable in a hedonic price function to explain the rent of apartments and to derive an implicit price of the landscape quality.

Analyse comparée de régimes institutionnels de gestion des réseaux urbains de l'eau en station touristique de montagne : les cas de Crans-Montana (Suisse) et de Morzine-Avoriaz (France)

La station touristique représente un espace urbain consacré principalement au tourisme, tout en comprenant également une population résidente permanente. Du point de vue de la gestion des réseaux urbains de l'eau, cette caractéristique induit pour ce type de lieu des usages propres à tout espace urbain mais également des spécificités liées à la forte fluctuation saisonnière de la population résidente ou encore à la présence d'usages particuliers tels que l'irrigation des golfs, la production de neige artificielle ou le thermalisme. Dès lors, la planification de l'approvisionnement est délicate et peu prévisible. Ces difficultés sont renforcées par le fait que les concentrations temporelles de la demande coïncident généralement avec des périodes de stress hydrique notable. Dans le cas de stations balnéaires, les pics de fréquentation interviennent en général durant l'été lorsque la ressource en eau est peu disponible. Le problème est similaire dans les stations touristiques de montagne où l'eau est généralement indisponible car stockée sous forme de neige durant les mois de forte fréquentation. De plus, ces difficultés sont souvent renforcées par la localisation géographique des stations touristiques, fréquemment situées dans des espaces sensibles du point de vue de la ressource en eau, avec des situations de pénuries temporelles, voire structurelles. Ces problématiques propres à la plupart des stations touristiques mènent souvent à de fortes rivalités entre, d'une part, les différents usages touristiques de la ressource, et d'autre part, les usages autochtones et touristiques. Les particularités liées au tourisme tendent ainsi à renforcer les rivalités entre différents types de secteurs d'activité (approvisionnement en eau potable, tourisme, hydroélectricité, enneigement artificiel, irrigation, etc.). Ces différents usages de la ressource mis en concurrence nécessitent dès lors la mise en oeuvre de réglementations structurées à travers des politiques publiques ainsi que des droits de propriété et selon des composantes nationales, régionales et locales ; soit un cadre institutionnel que nous proposons d'appeler Régime Institutionnel de Ressource (RIR) (Knoepfel et al. 2001, 2007). A travers cette thèse de doctorat, nous répondons à différentes questions de recherche. Nous tentons d'abord de comprendre comment ces différents RIR sont-ils mis en oeuvre dans le cadre d'espaces touristiques ? Comment ceux-ci sont-ils concrétisés par les acteurs et quels sont leurs effets en termes de durabilité technique, environnementale, sociale et économique des réseaux urbains de l'eau ? Nous questionnons ensuite les effets du tourisme sur la gestion des infrastructures de réseau à l'échelle de la station touristique et de son bassin versant et nous interrogeons sur les effets du tourisme en termes de gestion des eaux urbaines. Nous portons notre attention sur deux stations touristiques situées dans deux contextes institutionnels différents (Crans-Montana en Suisse et Morzine-Avoriaz en France) et y étudions trois types de régimes institutionnels en particulier : la régie directe (gestion publique), l'affermage (gestion déléguée) et la gestion privée des infrastructures. Les résultats de cette thèse de doctorat indiquent tout d'abord dans quelle mesure le tourisme modifie de façon significative la perception et les modalités de gestion de la ressource en eau et des infrastructures. Ils montrent ensuite que l'espace fonctionnel de la gestion de ces infrastructures correspond rarement aux limites du réseau hydrographique naturel et quelles en sont les implications en termes de durabilité. Enfin, la comparaison de différents régimes institutionnels révèle les forces et les faiblesses de chaque modèle de gestion dans le cas spécifique des stations touristiques et également les différentes solutions adoptées localement pour la mise en oeuvre d'un arrangement institutionnel permettant un usage plus ou moins durable des infrastructures de réseau et du réseau hydrographique naturel. - Tourism resort represents an urban area mainly dedicated to tourism while including at the same time a permanent residential population. From the point of view of urban water networks, this characteristic induces a strong seasonal fluctuation of residential population and involves special water uses such as golf irrigation, production of artificial snow or functioning of thermal baths. Therefore, water supply planning can be tricky and difficult to predict. These difficulties are reinforced by the fact that temporary concentrations of water demand coïncidé generally with periods of water stress. In the case of seaside resorts, frequenting peaks arise in general during summer when water resource is less available. The problem is similar in mountainous tourist resorts where water is generally unavailable as it is stored as snow during months of highest frequenting. Furthermore, these difficulties are often reinforced by resorts' geographical localisations, which are often situated in sensitive areas in terms of temporary or structural water shortages. These problematic issues often lead to strong rivalries between tourists' water uses on the one hand, and between locals and tourists uses on the other hand. Thus, features of tourism tend to reinforce rivalries between different sectors of activity (supply of drinking water, tourism, hydroelectricity, artificial snow, irrigation, etc.). These different and competing water uses need the implementation of rules structured through public policies and property rights and through national, regional and local legal components; We propose to call this framework as an Institutional Resource Regime (IRR) (Knoepfel et al. 2001, 2007, 2009). Through this PhD thesis, we answer different research questions. We firstly aim to understand how those different IRR are implemented within tourism spaces? How do actors materialize them and what are their effects in term of technical, environmental, social and economical sustainability of urban water networks? We then, investigate effects of tourism on water networks infrastructures' management at the scale of the tourist resort and its river basin. We focus our attention on two tourist resorts situated within two different institutional contexts (Crans-Montana, Switzerland and Morzine-Avoriaz, France) and study three types of institutional regime in particular: public, delegated and private management of infrastructures. Results of this PhD thesis indicate firstly how tourism modifies in a significant way the perception and management modalities of water resource and infrastructures. Results also show that functional space of infrastructures management rarely matches with the limits of the natural river basin and indicates what it means in terms of sustainability. Finally, the comparison of different institutional regimes reveals the strengths and weakness of each management model in the specific case of tourist resorts and shows the different solutions in locally implementing an institutional arrangement for a more or less sustainable management of network infrastructures and natural water system.

Analyse systémique et prospective des usages de l'eau dans la région de Crans-Montana-Sierre (Suisse)

Crans-Montana-Sierre is a tourist area locateci in Rhone valley in central Valais, cha-racterized by dry climate and scarce summer precipitations. More than other regions in Switzerland, this area has suffered the effects of the drought (heat wave) that affec¬ted all Western Europe during summer 2003. In the future, climate change together with societal and economic development will signicantly modify the water need of the region and, consequently, may increase the potential conflicts of interest. Within a long term planning strategy, decision-makers require precise information about the current amount of water needed in the region, with particular attention to temporal and spatial concentration, and the forecasted amount for 2050. This work therefore aims at estimating the variation of the water demand by taking into account the influence of climate change (CH2011) and socio-economic scenarios, developed in cooperation with the competent authorities. This thesis, whose aim is to study the water management and water uses is a core part of the MontanAqua project "Water management in times of scarcity and global change" mainly because of its interdisciplinary topic at the interface between water resources, land development and the socio-political structure. Results show that socio-economic development by 2050 could have a greater impact than expected climate changes (CH2011, A1B scenarios) for the same time horizon for water demand. Demography, spatial planning, tourism and economic development are just some of the factors that could significantly affect the water consumption of the Crans-Montana-Sierre region. Compared with the future water resources available, the maximal water demand forecasted by the socio-economic scenarios developed within the project MontanAqua, could not always be satisfied. This issue, like extreme climate phenomena (as it was the summer drought occurred in 2003 or in April / May 2011), could be mitigated adopting regional management policies relating to a more rational water use and preventive storage of water resource. - Crans-Montana-Sierre est une région touristique située dans la vallée du Rhône; dans le Valais central, qui se caractérise par un climat relativement pauvre en précipitations et qui plus que d'autres a subi les effets de la sécheresse qui a touché l'Europe occidentale durant l'été 2003. À l'avenir, les changements climatiques ainsi que le développement socio-économique modifieront de manière significative les besoins en eau de la région, ce qui risque de faire augmenter les rivalités d'usage concernant cette ressource. Afin de jouer à l'avance, les décideurs ont besoin d'informations précises sur la quantité d'eau nécessaire à la région, avec une attention particulière à sa concentration temporelle et spatiale, à l'heure actuelle et à l'horizon 2050. Ce travail vise donc à estimer la variation de la demande en eau en tenant compte de l'influence des changements climatiques (CH2011) et des scénarios socio-économiques, élaborés en collaboration avec les autorités compétentes. Cette thèse, qui met l'accent sur les usages de l'eau fait partie du projet Montan Aqua « Gestion de l'eau en temps de pénurie et de changement global », est à l'intersection entre les ressources hydriques, l'aménagement du territoire et son organisation socio-politique, fait qui la met, non pas par son importance, mais par son emplacement et ses interconnexions, au coeur de cette recherche. Les résultats obtenus montrent comment les développements socio-économiques d'ici à 2050 ont un impact potentiellement plus important que les changements climatiques prévus par les scénarios AlB de CH2011 pour le même horizon temporel sur la demande en eau. Démographie, aménagement du territoire et contexte économico-touristique, ne sont que quelques-uns des facteurs qui ont la capacité d'agir significativement sur les usages de l'eau en ce qui concerne les aspects qualitatif et quantitatif de la région de Crans-Montana-Sierre. Par rapport aux ressources en eau disponibles à l'avenir, la demande maximale d'eau prévue par les scénarios socio-économiques développés au sein du projet MontanAqua risque de ne pas être toujours satisfaite. Ce danger et la manifestation de phénomènes climatiques extrêmes, comme la sécheresse estivale survenue en 2003 ou celle d'avril/mai 2011, ne pourront être atténués que par l'adoption de politiques de gestion à l'échelle régionale favorisant une utilisation plus rationnelle et un stockage préventif de la ressource en eau.

Habiter touristique et agencement de l'espace urbain : le cas de Los Angeles : recherche sur le concours des compétences des individus quant à leurs manières de faire avec les épreuves spatiales d'une métapole touristique

Vivre, c'est passer d'un espace à un autre en essayant le plus possible de ne pas se cogner déclamait George Pérec. Cet énoncé poétiquement géographique pourrait résumer d'une certaine façon le défi de connaissance saisi par cette recherche. L'enjeu consiste effectivement à envisager le fait à'habiter, entendu dans son acception du « faire avec de l'espace » de la part des individus, comme n'allant pas de soi, de mettre en exergue le caractère problématique que constitue la pratique d'un lieu pour un individu. A ce titre, l'une des propositions de ce travail est de considérer tout lieu comme un assemblage d'épreuves spatiales face auxquelles les individus sont confrontés. La question se pose alors de savoir comment les individus font avec ces épreuves spatiales. L'hypothèse défendue dans ce travail est celle de la mobilisation, par ces derniers, de compétences - ressortissant d'une « capacité à » telle qu'exprimée par Wittgenstein dans le domaine linguistique, c'est-à-dire d'une « maîtrise technique » - et d'un capital spatial - que l'on peut faire synthétiquement correspondre à l'expérience accumulée par un individu en terme de pratique de lieux. L'argumentation étaye l'hypothèse que les manières d'habiter touristiquement une métropole dépendent notamment de ces deux éléments interdépendants dont dispose tout individu de façon variable et évolutive ; leur importance, sans déterminer aucunement des pratiques spécifiques, participe d'une maîtrise accrue de l'espace, d'une facilité pour faire avec les épreuves spatiales, atténuant le caractère potentiellement contraignant de ces dernières. Il s'agit donc d'une enquête menant une réflexion tout à la fois sur la dimension actorielle des individus, mais également sur le lieu en tant qu'espace habité : travailler sur cette question revient à investir la question de l'agencement urbain d'un lieu, c'est-à-dire d'appréhender la façon dont une configuration urbaine (les épreuves spatiales coïncidant avec les principales caractéristiques de cette dernière) est habitée, et plus particulièrement en l'occurrence ici, est habitée touristiquement. Pour aborder empiriquement cette problématique, l'enquête se focalise donc sur les touristes : d'une part pour leur faible degré de familiarité avec le lieu pratiqué (faire avec cet espace ne relève donc pas d'une routine) et d'autre part parce que leur présence dorénavant massive au sein des métropoles a des effets sur l'agencement de ces lieux qu'il est nécessaire d'envisager. Le laboratoire utilisé est celui de Los Angeles, cette aire urbaine de 18 millions de résidents : son étalement considérable, l'absence d'un centre-ville historiquement important, et la forte prégnance de sa métrique automobile étant des caractéristiques qui font de ce lieu un « exceptionnel normal » aux épreuves spatiales particulièrement proéminentes. La recherche avance à ce titre des arguments permettant d'en souligner un agencement, par les manières d'habiter des touristes, différencié du modèle classique de la métropole touristique : pour exprimer cette singularité, l'enquête étaye l'hypothèse consistant à qualifier ce lieu de métapole touristique. - Living is moving from one space to another while trying not to collide claimed George Pérec. This poetically geographic statement could in a way sum up the challenge seized by this research. The challenge is indeed to consider the fact of dwelling, in the sense of "make do with space" on the part of individuals, as not an evidence but highlighting the problematic characteristics of the practice of a place by people. Accordingly, one of the proposals of this work is to consider each place as a gathering of spatial stakes against which individuals are faced. The question then arises how are individuals facing these spatial stakes. The hypothesis debated in this work is that of the mobilization of skills such as "the ability of' as expressed by Wittgenstein in the linguistic field, i.e. a "technical mastery" - and a spatial capital - that can synthetically correspond to the experience accumulated by one single individual in terms of practice of places. Argument supports the hypothesis that the ways of touristically dwelling a metropolis depend on these two interdependent elements which everyone deal with in a variable and scalable manner; their importance, without determining any specific practices, participates in an increased proficiency of space, easing to make do with the space stakes, moderating the potentially binding character of the latter. It is therefore a survey leading a reflection both on the actorial dimension of individuals, but also on the place as a living space: working on this issue is exploring the question of the urban layout of a place, i.e. to understand how an urban configuration (the space stakes coinciding with the main features of the latter) is inhabited, and in particular in the present case, is touristically dwelled. To empirically address this issue, the inquiry therefore focuses on tourists: on the one hand for their low degree of familiarity with the place (make do with this space is therefore not a routine) and secondly because their now massive presence within the metropolis has effects on the layout of these places that is necessary to consider. The laboratory used is that of Los Angeles, this urban area of 18 million residents: its considerable spread, the absence of an historically important downtown» and high salience of "automobile metric" are features that make this place a "normal exceptional" with particularly prominent space stakes. Hence, research advances the arguments underlining the layout, by the ways of tourists dwelling different from the classical model of the metropolis: to express this uniqueness, the survey supports hypothesis to describe this place as a tourist metapolis.

Das Auerhuhn im Jura: Qualität des Lebensraum, Demographie, Habitatwahl und nicht-invasive genetische Untersuchungen

Most Central European Capercaillie populations have been declining during the last century. In the Jura Mountains, at the border between Switzerland and France, remaining Capercaillie populations are now isolated and endangered. In this study, land-use and Capercaillie presence data were used to identify key landscape parameters by logistic regression modelling. We found that Capercaillie prefers areas at the highest altitude in the Jura Mountains that are characterised by continous forests and stands with intermediate canopy cover. At the local scale, winter habitat selection revealed a preference for open forests with a sparse canopy cover dominated by spruce and fir. Capercaillie avoided dense undercanopy and understorey, especially when dominated by beech. Population viability and sensitivity analyses underlined the crucial importance of adult female survival, chick survival and breeding success for populations maintenance. Legal bases, scientific knowledge and technical measures are now available to conserve the flagship species Capercaillie within Jura Mountains. Capercaillie-adapted forestry requires a mosaic distribtution of habitat types, with a matrix of open forests where fir is favoured, and understorey kept sparse. Preliminary essays indicate that grouse-adapted forestry costs are similar or even lower than present costs. To increase survival and breeding sucess, one option is to diminish human distrubance by limiting access to Capercailllie breeding and wintering areas. An action plan for the species should avoid more costly and intensive approaches such as the reintroduction of birds from other populations. Capercaillie conservaiton represents a major challenge rising from various and contradictory leisure, tourist and rural development activities. Collaborations with different stakeholders and state agencies for forestry with an effective protection from human distrubance.

Prevalence and time course of acute mountain sickness in older children and adolescents after rapid ascent to 3450 meters

OBJECTIVE: Acute mountain sickness is a frequent and debilitating complication of high-altitude exposure, but there is little information on the prevalence and time course of acute mountain sickness in children and adolescents after rapid ascent by mechanical transportation to 3500 m, an altitude at which major tourist destinations are located throughout the world. METHODS: We performed serial assessments of acute mountain sickness (Lake Louise scores) in 48 healthy nonacclimatized children and adolescents (mean +/- SD age: 13.7 +/- 0.3 years; 20 girls and 28 boys), with no previous high-altitude experience, 6, 18, and 42 hours after arrival at the Jungfraujoch high-altitude research station (3450 m), which was reached through a 2.5-hour train ascent. RESULTS: We found that the overall prevalence of acute mountain sickness during the first 3 days at high altitude was 37.5%. Rates were similar for the 2 genders and decreased progressively during the stay (25% at 6 hours, 21% at 18 hours, and 8% at 42 hours). None of the subjects needed to be evacuated to lower altitude. Five subjects needed symptomatic treatment and responded well. CONCLUSION: After rapid ascent to high altitude, the prevalence of acute mountain sickness in children and adolescents was relatively low; the clinical manifestations were benign and resolved rapidly. These findings suggest that, for the majority of healthy nonacclimatized children and adolescents, travel to 3500 m is safe and pharmacologic prophylaxis for acute mountain sickness is not needed.

The Impact of Housing Market Segmentation between Tourists and Residents on the Hedonic Price for Landscape Quality

Market segmentation is an important issue when estimating the implicit price for an environmental amenity from a surrogate market like property. This paper tests the hypothesis of a segmentation of the housing market between tourists and residents and computes the implicit price for natural landscape quality in Swiss alpine resorts. The results show a clear segmentation between both groups of consumers, although tests also show that the estimated coefficient for landscape is similar in the tourists' model and in the residents'. However, since the functional form is non linear, the nominal - rather than relative - value of a change in natural landscape quality is higher in the tourist housing market than in the residents'. Hence, considering the segmentation of the market between tourists and residents is essential in order to provide valid estimates of the nominal implicit price of natural landscape quality.

Géotourisme et utilisation de sites naturels d'intérêt pour les sciences de la Terre: les régions de Crans-Montana-Sierre (Valais, Alpes suisses) et Chamonix-Mont-Blanc (Haute-Savoie, Alpes françaises)

Résumé : Au travers de l'étude des régions de Crans-Montana-Sierre (Valais, Suisse) et de Chamonix-Mont-Blanc (Haute-Savoie, France), cette recherche considère les liens existants entre activités touristiques et sciences de la Terre. Ainsi, les sites géologiques et géomorphologiques pris en compte sont perçus comme ayant non seulement une valeur scientifique, mais aussi un intérêt scénique, culturel et économique. D'un point de vue (géo)touristique, différents modèles d'analyse sont proposés pour expliciter les composantes de l'offre et de la demande et comprendre le cycle de vie des objets étudiés. L'offre que constituent ces sites est tout d'abord présentée afin d'évaluer leurs différents potentiels, ainsi que l'utilisation spatio-temporelle, didactique et économique qui en est faite. Ensuite, les logiques d'acteurs sont analysées au travers des phases de valorisation, d'exploitation et de transformation, dans le but de comprendre les facteurs et les projets d'utilisation les concernant. Enfin, la demande des différents publics cibles, de même que leurs caractéristiques socio-touristiques et (géo)didactiques, sont discutées. Pour ce faire, des méthodes d'inventaire, d'évaluation, d'entretien et de questionnaire ont été utilisées, à différentes échelles d'analyse. On constate d'abord que le pôle des valeurs scénique et économique présente une plus forte mise à contribution, par rapport à l'utilisation didactique. De plus, le niveau de protection des sites ne restreint généralement pas leur exploitation, au contraire du facteur risque. Du point de vue des publics cibles, une forte demande d'explications didactiques est exprimée, s'orientant vers une approche multithématique des potentiels à mettre en valeur; des biens et services de base sont ainsi demandés. Enfin, force est de constater que seuls de grands projets peuvent rendre les activités (géo)touristiques rentables. A l'avenir, sachant que le géotourisme peut répondre à une demande touristique liée au rêve et à l'émotion, l'approche de l'offre devrait intégrer une réflexion en didactique des sciences de la Terre, d'autant que cette forme de tourisme tend à devenir une composante du développement économique régional, notamment en dehors de la saison d'hiver. Idéalement, l'utilisation touristique de la géodiversité devrait s'accompagner d'une politique de protection dynamique, combinant préservation et mise en valeur. A terme, le but ultime de cette entreprise est notamment d'élargir la notion de patrimoine culturel, pour favoriser une approche transdisciplinaire du paysage Abstract : Based on the study of the areas of Crans-Montana-Sierre (Valais, Switzerland) and Chamonix-Mont-Blanc (Haute-Savoie, France), this study considers the links between tourism activities and Earth science. Thus, the studied geological and geomorphological sites have not only a scientific va1ue, but also scenic, cultural and economic value. From a point of view of tourism, different models of analysis are examined in order to explain the components of the supply and the demand, and to understand the life cycles of the considered objects. The primary product of these sites is first presented, in order to assess their different potential as well as their didactic, economic, spatial and temporal use. The stakeholders' behaviour is then analysed to understand the factors and projected use, with the help of the optimisation, exploitation and transformation phases. Finally, the demand of the different target markets as well as their socio-tourist and (geo)didactic characteristics are discussed. To complete this study, methods of census, assessment, interviewing and questionnaire surveying are used, at different scales of analysis. The main results appear to demonstrate that the scenic and economic values present a higher value relative to the didactic use. Moreover, the required conservation measures for the studied sites do not generally restrict the use, on the contrary to the "risk" factor. From the point of view of the target market, a relevant requirement for explanatory commentary is expressed and tends towards an approach optimising different themes to utilise potential; basic popular goods and services are also requested. Finally, it is clearly demonstrated that only relevant projects are able to make this kind of activity profitable. For the future, geotourism may be marketed to a tourist demand for imagination and emotion. Consequently, the product approach should integrate a reflection on Earth science popularisation given that this branch of tourism tends to receive a component of the economic and regional development, notably during the summer period. However, the use of geodiversity should include a concept of dynamic management, taking into account conservation as well as tourism development. Thus, the final aim of this process is to r,r'iden the notion of cultural heritage, in order to stimulate a multidisciplinary approach to the landscape.

Acute and Chronic Altitude-Induced Cognitive Dysfunction in Children and Adolescents.

OBJECTIVE: To assess whether exposure to high altitude induces cognitive dysfunction in young healthy European children and adolescents during acute, short-term exposure to an altitude of 3450 m and in an age-matched European population permanently living at this altitude. STUDY DESIGN: We tested executive function (inhibition, shifting, and working memory), memory (verbal, short-term visuospatial, and verbal episodic memory), and speed processing ability in: (1) 48 healthy nonacclimatized European children and adolescents, 24 hours after arrival at high altitude and 3 months after return to low altitude; (2) 21 matched European subjects permanently living at high altitude; and (3) a matched control group tested twice at low altitude. RESULTS: Short-term hypoxia significantly impaired all but 2 (visuospatial memory and processing speed) of the neuropsychological abilities that were tested. These impairments were even more severe in the children permanently living at high altitude. Three months after return to low altitude, the neuropsychological performances significantly improved and were comparable with those observed in the control group tested only at low altitude. CONCLUSIONS: Acute short-term exposure to an altitude at which major tourist destinations are located induces marked executive and memory deficits in healthy children. These deficits are equally marked or more severe in children permanently living at high altitude and are expected to impair their learning abilities.