Preface: Special Issue on Environmental Impact of Nature‐Based Tourism.

Tourism is growing rapidly throughout the world, including nature‐based tourism, but natural habitats are shrinking. How do we avoid damaging what is left as an increasing number of visitors wish to experience nature or enjoy adventure or relaxation in natural surroundings? This issue explores various environmental impact factors, from the physical effects of trampling through the disturbance of wildlife to the attitudes of visitors and how well‐run tourism ventures might modify their behavior

Population Dynamics of the Critically Endangered\ud Golden Lancehead Pitviper, Bothrops insularis: Stability\ud or Decline?

Little is known about vital rates of snakes generally because of the difficulty in collecting data. Here we used a robust design\ud mark-recapture model to estimate survival, behavioral effects on capture probability, temporary emigration, abundance and\ud test the hypothesis of population decline in the golden lancehead pitviper, Bothrops insularis, an endemic and critically\ud endangered species from southeastern Brazil. We collected data at irregular intervals over ten occasions from 2002 to 2010.\ud Survival was slightly higher in the wet season than in the dry season. Temporal emigration was high, indicating the\ud importance of accounting for this parameter both in the sampling design and modeling. No behavioral effects were\ud detected on capture probability. We detected an average annual population decrease (l= 0.93, CI = 0.47–1.38) during the\ud study period, but estimates included high uncertainty, and caution in interpretation is needed. We discuss the potential\ud effects of the illegal removal of individuals and the implications of the vital rates obtained for the future persistence and\ud conservation of this endemic, endangered species

Unilateral giant renal angiomyolipoma and pulmonary lymphangioleiomyomatosis

Angiomyolipomas (AMLs) are mesenchymal neoplasms, named so because\ud of the complex tissue composition represented by variable proportions of\ud mature adipose tissue, smooth muscle cells, and dysmorphic blood vessels.\ud Although AMLs may rise in different sites of the body, they are mostly observed\ud in the kidney and liver. In the case of renal AMLs, they are described in two\ud types: isolated AMLs and AMLs associated with tuberous sclerosis (TS). While\ud most cases of AMLs are found incidentally during imaging examinations and\ud are asymptomatic, others may reach huge proportions causing symptoms.\ud Pulmonary lymphangioleiomyomatosis (LAM) is a rare benign disease\ud characterized by cystic changes in the pulmonary parenchyma and smooth\ud muscle proliferation, leading to a mixed picture of interstitial and obstructive\ud disease. AML and LAM constitute major features of tuberous sclerosis\ud complex (TSC), a multisystem autosomal dominant tumor-suppressor gene\ud complex diagnosis. The authors report the case of a young female patient\ud who presented a huge abdominal tumor, which at computed tomography (CT)\ud show a fat predominance. The tumor displaced the right kidney and remaining\ud abdominal viscera to the left. Chest CT also disclosed pulmonary lesions\ud compatible with lymphangioleiomyomatosis. Because of sudden abdominal\ud pain accompanied by a fall in the hemoglobin level, the patient underwent an\ud urgent laparotomy. The excised tumor was shown to be a giant renal AML with\ud signs of bleeding in its interior. The authors call attention to the diagnosis of\ud AML and the huge proportions that the tumor can reach, as well as for ruling\ud out the TSC diagnosis, once it may impose genetic counseling implications

Facteurs pronostiques du cancer de l'endomètre (à propos de 585 cas)

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Nature Conservation and Nature-Based Tourism: A Paradox?

Throughout the world, areas have been reserved for their exceptional environmental values, such as high biodiversity. Financial, political and community support for these protected areas is often dependent on visitation by nature-based tourists. This visitation inevitably creates environmental impacts, such as the construction and maintenance of roads, tracks and trails; trampling of vegetation and erosion of soils; and propagation of disturbance of resilient species, such as weeds. This creates tension between the conservation of environmental values and visitation. This review examines some of the main features of environmental impacts by nature-based tourists through a discussion of observational and manipulative studies. It explores the disturbance context and unravels the management implications of detecting impacts and understanding their causes. Regulation of access to visitor areas is a typical management response, qualified by the mode of access (e.g., vehicular, ambulatory). Managing access and associated impacts are reviewed in relation to roads, tracks and trails; wildlife viewing; and accommodations. Responses to visitor impacts, such as environmental education and sustainable tour experiences are explored. The review concludes with ten recommendations for further research in order to better resolve the tension between nature conservation and nature-based tourism

Ge Dots Self-Assembling: Surfactant Mediated Growth of Ge on Sige (118) Stress-Induced Kinetic Instabilities

The ordering of islands on naturally or artificially nanostructured surfaces is one of the most recent objectives among actual nanotechnology challenges. We show in this letter that, by a combination of two approaches, i.e., a two-step molecular beam epitaxy (MBE) deposition process and surfactant-mediated growth, we are able to obtain chains of nicely ordered ultrasmall islands of lateral size below 50 nm. The two-step MBE process consists of vicinal Si(001) surface self-patterning by SiGe growth instability and Ge dot ordering by subsequent Ge deposition on a SiGe template layer. The surfactant-mediated growth consists of submonolayer Sb deposition prior to Ge growth, in order to reduce the island size up to 25 nm. The best ordering of Ge islands is obtained when the island size matches the wavelength of the template layer

Size-Dependent Quantum Efficiency of Luminescence in Self Assembled Germanium Nanocrystals

Self-assembled Ge nanocrystals (NCs), as verified from transmission electron microscopy and Raman spectroscopy, were formed by in-situ thermal annealing of a thin amorphous Ge layer deposited by molecular beam epitaxy on a thin SiO2 layer on Si(001). The Ge NCs were then capped in situ with a thin layer of amorphous Si to prevent oxidation. For samples with average NC diameters ranging from 2.5 to 60 nm, the NC photoluminescence (PL) appeared primarily as a wide near-infrared band peaked near 800 meV. Using both the k•p and tight binding theoretical models, we have analyzed the PL spectrum in terms of the NC size distribution required to reproduce the observed asymmetric band shape, which includes, for the smaller diameter NCs, a bandgap enlargement due to quantum confinement. The peak energy of the PL band reflects the average NC size and its shape depends on the NC size distribution. The observed size distribution determined from transmission electron microscopy analysis allowed the determination of the nonlinear increase in the PL quantum efficiency with decreasing NC diameter. Alternatively, given a good theoretical description of the system, it is thus possible to evaluate the size distribution of semiconductor NCs from their PL energy dependence.</jats:p

Photoluminescence Quantum Efficiency of Self Assembled Germanium Nanocrystals

Abstract not Available.</jats:p

Size-dependent quantum efficiency of luminescence in self assembled germanium nanocrystals

Peer reviewed: YesNRC publication: Ye