High-pressure synthesis and structural behavior of sodium orthonitrate Na3NO4

Sodium orthonitrate (Na3NO4) is an unusual phase containing the first example of isolated tetrahedrally bonded NO43- groups. This compound was obtained originally by heating together mixtures of Na2O and NaNO3 for periods extending up to > 14 days in evacuated chambers. Considering the negative volume change between reactants and products, it was inferred that a high-pressure synthesis route might favor the formation of the Na3NO4 compound. We found that the recovered sample is likely to be a high-pressure polymorph, containing NO43- groups as evidenced by Raman spectroscopy. The high-pressure behavior of Na3NO4 was studied using Raman spectroscopy and synchrotron X-ray diffraction in a diamond anvil cell above 60 GPa. We found no evidence for major structural transformations, even following laser heating experiments carried out at high pressure, although broadening of the Raman peaks could indicate the onset of disordering at higher pressure

Climate Change and American Bullfrog Invasion: What Could We Expect in South America?

BACKGROUND: Biological invasion and climate change pose challenges to biodiversity conservation in the 21(st) century. Invasive species modify ecosystem structure and functioning and climatic changes are likely to produce invasive species' range shifts pushing some populations into protected areas. The American Bullfrog (Lithobates catesbeianus) is one of the hundred worst invasive species in the world. Native from the southeast of USA, it has colonized more than 75% of South America where it has been reported as a highly effective predator, competitor and vector of amphibian diseases. METHODOLOGY/PRINCIPAL FINDINGS: We modeled the potential distribution of the bullfrog in its native range based on different climate models and green-house gases emission scenarios, and projected the results onto South America for the years of 2050 and 2080. We also overlaid projected models onto the South American network of protected areas. Our results indicate a slight decrease in potential suitable area for bullfrog invasion, although protected areas will become more climatically suitable. Therefore, invasion of these sites is forecasted. CONCLUSION/SIGNIFICANCE: We provide new evidence supporting the vulnerability of the Atlantic Forest Biodiversity Hotspot to bullfrog invasion and call attention to optimal future climatic conditions of the Andean-Patagonian forest, eastern Paraguay, and northwestern Bolivia, where invasive populations have not been found yet. We recommend several management and policy strategies to control bullfrog invasion and argue that these would be possible if based on appropriate articulation among government agencies, NGOs, research institutions and civil society

Strategy for the management of diabetic macular edema: the European Vitreo-Retinal Society macular edema study

Objective. To compare the efficacy of different therapies in the treatment of diabetic macular edema (DME). Design. Nonrandomized, multicenter clinical study. Participants. 86 retina specialists from 29 countries provided clinical information on 2,603 patients with macular edema including 870 patients with DME. Methods. Reported data included the type and number of treatment(s) performed, the pre-and posttreatment visual acuities, and other clinical findings.The results were analyzed by the French INSEE (National Institute of Statistics and Economic Studies). Main Outcome Measures. Mean change of visual acuity and mean number of treatments performed. Results.The change in visual acuity over time in response to each treatment was plotted in second order polynomial regression trend lines. Intravitreal triamcinolone monotherapy resulted in some improvement in vision. Treatmentwith threshold or subthreshold grid laser also resulted in minimal vision gain. Anti-VEGF therapy resulted in more significant visual improvement. Treatment with pars plana vitrectomy and internal limiting membrane (ILM) peeling alone resulted in an improvement in vision greater than that observed with anti-VEGF injection alone. In our DME study, treatment with vitrectomy and ILM peeling alone resulted in the better visual improvement compared to other therapies

L'aménagement rural et la région : problèmes de méthodes

[fre] On ne peut comprendre les mutations actuelles de la société rurale et espérer agir sur elles sans une conception globale de l'aménagement. Deux catégories d'études existent, les études « à grandes mailles » et les études par « secteur >. Elles doivent aboutir à des documents d'orientation. Pour que l'information ainsi fournie soit adaptée à la prise de décision, elle doit être lisible, pratique et précise. . Toute étude doit apporter une réponse à ces questions : où, pourquoi, comment faut-il intervenir ? . L'administration fait exécuter de plus en plus d'études d'aménagement rural. Une doctrine et une méthodologie s'élaborent ainsi. L'aménagement ne peut être inspiré par une conception autarcique du développement rural. Il doit au contraire être le support d'une concertation des initiatives locales et extérieures pour appliquer en vraie grandeur les orientations déterminées. [eng] It is impossible to understand change in rural society to day and to try to influence it without referring to an all round conception of planning. There are two kinds of studies, broad surveys and sector analysis. This information, to be used in decision making has to be precise, practical and understandable. . Each survey should answer these questions : where, why, how must we act ? . The State orders more and more country planning surveys. A methodology and a philosophy of this type of surveys have thus been developed. Country planning cannot be inspired by an autarcie idea of rural development. It should on the contrary support local and external initiatives to realize the goals fixed.

Climate change threatens micro-endemic amphibians of an important South American high-altitude center of endemism

Species inhabiting broad altitudinal gradients are particularly exposed to the effects of global climate change (GCC). Those species reaching mountain tops are the most negatively affected. Here, using ecological niche models we estimated the climate change exposure of endemic amphibians of the most important extra-Andean mountain system of Argentina: The Sierras Pampeanas Centrales. Our results pinpoint that micro-endemic amphibians of this mountain system are heavily exposed to the effects of GCC, with important constraints of suitable climatic conditions for the six analyzed species. Among the most important findings, our models predict a high probability of a total disappearance of suitable climatic conditions for two of the species, currently restricted to mountain tops. This high exposure, in synergy with their very restricted ranges, and other important human induced threats (as fish invasion and emergent diseases), pose a serious threat to these endemic species, which can enter into the "extinction pathway" in a near future if no concrete conservation actions are taken. Our findings provide additional evidence of the great negative impact of GCC in high-altitude centers of endemism.Fil: Cordier, Javier Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Lescano, Julián Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Ríos, Natalia E.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; ArgentinaFil: Leynaud, Gerardo Cristhian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Nori, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin