3 research outputs found

    Future hydrological regimes and glacier cover in the Everest region: The case study of the upper Dudh Koshi basin

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    Assessment of future water resources under climate change is required in the Himalayas, where hydrological cycle is poorly studied and little understood. This study focuses on the upper Dudh Koshi river of Nepal (151 km2, 4200–8848 m a.s.l.) at the toe of Mt. Everest, nesting the debris covered Khumbu, and Khangri Nup glaciers (62 km2). New data gathered during three years of field campaigns (2012–2014) were used to set up a glacio-hydrological model describing stream flows, snow and ice melt, ice cover thickness and glaciers' flow dynamics. The model was validated, and used to assess changes of the hydrological cycle until 2100. Climate projections are used from three Global Climate Models used in the recent IPCC AR5 under RCP2.6, RCP4.5 and RCP8.5. Flow statistics are estimated for two reference decades 2045–2054, and 2090–2099, and compared against control run CR, 2012–2014. During CR we found a contribution of ice melt to stream flows of 55% yearly, with snow melt contributing for 19%. Future flows are predicted to increase in monsoon season, but to decrease yearly (− 4% vs CR on average) at 2045–2054. At the end of century large reduction would occur in all seasons, i.e. − 26% vs CR on average at 2090–2099. At half century yearly contribution of ice melt would be on average 45%, and snow melt 28%. At the end of century ice melt would be 31%, and snow contribution 39%. Glaciers in the area are projected to thin largely up to 6500 m a.s.l. until 2100, reducing their volume by − 50% or more, and their ice covered area by − 30% or more. According to our results, in the future water resources in the upper Dudh Koshi would decrease, and depend largely upon snow melt and rainfall, so that adaptation measures to modified water availability will be required

    Internal- vs external-connection single implants: A retrospective study in an italian population treated by certified prosthodontists

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    Purpose: The design of an implant connection that allows prosthetic suprastructures to be attached to implants has long been debated in the dental literature. The goal of this retrospective study was to evaluate the 5-year clinical results for a large number of single implants restored by certified prosthodontists in an attempt to establish whether different clinical outcomes could be detected for external- or internalconnection implants. Materials and Methods: All single implants with internal or external connections inserted in 27 private dental practices from January 1, 2003 to December 31, 2007 were evaluated. An initial statistical analysis was performed to describe the sample population at baseline and then to compare the two types of implant-abutment connection configurations and their clinical outcomes. All data were statistically analyzed with STATA12 (StataCorp). Results: Twenty-eight of the 85 active members of the Italian Academy of Prosthetic Dentistry (AIOP) participated in this study. The sample included 1,159 patients and 2,010 implants. Of the implants, 75 were dropped because there was no information about follow-up. Of the remaining implants, 1,431 (74.0%) were followed for at least 5 years, and 332 implants (17.2%) were followed for more than 8 years. Nearly 99% (98.9%) of the implants survived. The difference between the survival frequencies of the two types of implant-abutment connection configurations was not significant for each negative event (log-rank test, P > .05). There was no difference between the two types of implants regarding restoration fracture, implant screw loosening, and peri-implant disease. Conclusion: Within the limitations of this study, it can be suggested that there is no difference in clinical outcomes of single restorations joined to internal- or external-connection implants
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