74 research outputs found

    The IWAVE methodology applied to improve the state of knowledge of water resources in Latin America

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    This paper presents the first results of the RLA/7/018 Project ‘Improving Knowledge of Groundwater Resources to Contribute to their Protection, Integrated Management and Governance’ which through the application of the IWAVE methodology (IAEA Water Availability Enhancement Project) proposes strengthening of national capacity to conduct comprehensive assessments of water resources. Four Latin American countries (Argentina, Brazil, Ecuador and Nicaragua) began the identification of national gaps in hydrological understanding, data and information and prepared a work plan to address them. It is expected that the IWAVE approach will help countries become more efficient and effective to meet the different and specific problems related to the management of water resources

    Data Descriptor: Daily observations of stable isotope ratios of rainfall in the tropics

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    We present precipitation isotope data (δ2H and δ18O values) from 19 stations across the tropics collected from 2012 to 2017 under the Coordinated Research Project F31004 sponsored by the International Atomic Energy Agency. Rainfall samples were collected daily and analysed for stable isotopic ratios of oxygen and hydrogen by participating laboratories following a common analytical framework. We also calculated daily mean stratiform rainfall area fractions around each station over an area of 5° x 5° longitude/latitude based on TRMM/GPM satellite data. Isotope time series, along with information on rainfall amount and stratiform/convective proportions provide a valuable tool for rainfall characterisation and to improve the ability of isotope-enabled Global Circulation Models to predict variability and availability of inputs to fresh water resources across the tropics.Fil: Munksgaard, Niels C.. James Cook University; Australia. Charles Darwin University. School of Environmental Research; AustraliaFil: Kurita, Naoyuki. Nagoya University; JapónFil: Sánchez Murillo, Ricardo. Universidad Nacional; Costa RicaFil: Ahmed, Nasir. Bangladesh Atomic Energy Commission; BangladeshFil: Araguas, Luis. International Atomic Energy Agency (iaea); AustriaFil: Balachew, Dagnachew L.. International Atomic Energy Agency (iaea); AustriaFil: Bird, Michael I.. James Cook University; AustraliaFil: Chakraborty, Supriyo. Indian Institute of Tropical Meteorology; IndiaFil: Kien Chinh, Nguyen. Center for Nuclear Techniques; VietnamFil: Cobb, Kim M.. Georgia Institute of Technology; Estados UnidosFil: Ellis, Shelby A.. Georgia Institute of Technology; Estados UnidosFil: Esquivel Hernández, Germain. Universidad Nacional; Costa RicaFil: Ganyaglo, Samuel Y.. National Nuclear Research Institute; GhanaFil: Gao, Jing. Chinese Academy of Sciences; República de ChinaFil: Gastmans, Didier. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Kaseke, Kudzai F.. Indiana University-Purdue University Indianapolis; India. University of California Santa Barbara; Estados UnidosFil: Kebede, Seifu. Addis Ababa University; EtiopíaFil: Morales, Marcelo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Mueller, Moritz. Swinburne University of Technology; MalasiaFil: Poh, Seng Chee. Universiti Malaysia Terengganu; MalasiaFil: Santos, Vinícius dos. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Shaoneng, He. Nanyang Technological University; SingapurFil: Wang, Lixin. Indiana University-Purdue University Indianapolis; IndiaFil: Yacobaccio, Hugo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Zwart, Costijn. James Cook University; Australi

    HLA association with the susceptibility to anti-synthetase syndrome

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    Objective: To investigate the human leukocyte antigen (HLA) association with anti-synthetase syndrome (ASSD). Methods: We conducted the largest immunogenetic HLA-DRB1 and HLA-B study to date in a homogeneous cohort of 168 Caucasian patients with ASSD and 486 ethnically matched healthy controls by sequencing-based-typing. Results: A statistically significant increase of HLA-DRB1*03:01 and HLA-B*08:01 alleles in patients with ASSD compared to healthy controls was disclosed (26.2% versus 12.2%, P = 1.56E–09, odds ratio–OR [95% confidence interval–CI] = 2.54 [1.84–3.50] and 21.4% versus 5.5%, P = 18.95E–18, OR [95% CI] = 4.73 [3.18–7.05]; respectively). Additionally, HLA-DRB1*07:01 allele was significantly decreased in patients with ASSD compared to controls (9.2% versus 17.5%, P = 0.0003, OR [95% CI] = 0.48 [0.31–0.72]). Moreover, a statistically significant increase of HLA-DRB1*03:01 allele in anti-Jo-1 positive compared to anti-Jo-1 negative patients with ASSD was observed (31.8% versus 15.5%, P = 0.001, OR [95% CI] = 2.54 [1.39–4.81]). Similar findings were observed when HLA carrier frequencies were assessed. The HLA-DRB1*03:01 association with anti-Jo-1 was unrelated to smoking history. No HLA differences in patients with ASSD stratified according to the presence/absence of the most representative non-anti-Jo-1 anti-synthetase autoantibodies (anti-PL-12 and anti-PL-7), arthritis, myositis or interstitial lung disease were observed. Conclusions: Our results support the association of the HLA complex with the susceptibility to ASSD

    Modification and preservation of environmental signals in speleothems

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    Speleothems are primarily studied in order to generate archives of climatic change and results have led to significant advances in identifying and dating major shifts in the climate system. However, the climatological meaning of many speleothem records cannot be interpreted unequivocally; this is particularly so for more subtle shifts and shorter time periods, but the use of multiple proxies and improving understanding of formation mechanisms offers a clear way forward. An explicit description of speleothem records as time series draws attention to the nature and importance of the signal filtering processes by which the weather, the seasons and longer-term climatic and other environmental fluctuations become encoded in speleothems. We distinguish five sources of variation that influence speleothem geochemistry: atmospheric, vegetation/soil, karstic aquifer, primary speleothem crystal growth and secondary alteration and give specific examples of their influence. The direct role of climate diminishes progressively through these five factors. \ud \ud We identify and review a number of processes identified in recent and current work that bear significantly on the conventional interpretation of speleothem records, for example: \ud \ud 1) speleothem geochemistry can vary seasonally and hence a research need is to establish the proportion of growth attributable to different seasons and whether this varies over time. \ud \ud 2) whereas there has traditionally been a focus on monthly mean �´18O data of atmospheric moisture, current work emphasizes the importance of understanding the synoptic processes that lead to characteristic isotope signals, since changing relative abundance of different weather types might 1Corresponding author, fax +44(0)1214145528, E-mail: [email protected] control their variation on the longer-term. \ud \ud 3) the ecosystem and soil zone overlying the cave fundamentally imprint the carbon and trace element signals and can show characteristic variations with time. \ud \ud 4) new modelling on aquifer plumbing allows quantification of the effects of aquifer mixing. \ud \ud 5) recent work has emphasized the importance and seasonal variability of CO2-degassing leading to calcite precipitation upflow of a depositional site on carbon isotope and trace element composition of speleothems. \ud \ud 6) Although much is known about the chemical partitioning between water and stalagmites, variability in relation to crystal growth mechanisms and kinetics is a research frontier. \ud \ud 7) Aragonite is susceptible to conversion to calcite with major loss of chemical information, but the controls on the rate of this process are obscure. \ud \ud Analytical factors are critical to generate high-resolution speleothem records. A variety of methods of trace element analysis are available, but standardization is a common problem with the most rapid methods. New stable isotope data on Irish stalagmite CC3 compares rapid laser-ablation techniques with the conventional analysis of micromilled powders and ion microprobe methods. A high degree of comparability between techniques for �´18O is found on the mm-cm scale, but a previously described high-amplitude oxygen isotope excursion around 8.3 ka is identified as an analytical artefact related to fractionation of the laser-analysis associated with sample cracking. High-frequency variability of not less than 0.5o/oo may be an inherent feature of speleothem �´18O records

    Influence of antisynthetase antibodies specificities on antisynthetase syndrome clinical spectrum time course

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    Antisynthetase syndrome (ASSD) is a rare clinical condition that is characterized by the occurrence of a classic clinical triad, encompassing myositis, arthritis, and interstitial lung disease (ILD), along with specific autoantibodies that are addressed to different aminoacyl tRNA synthetases (ARS). Until now, it has been unknown whether the presence of a different ARS might affect the clinical presentation, evolution, and outcome of ASSD. In this study, we retrospectively recorded the time of onset, characteristics, clustering of triad findings, and survival of 828 ASSD patients (593 anti-Jo1, 95 anti-PL7, 84 anti-PL12, 38 anti-EJ, and 18 anti-OJ), referring to AENEAS (American and European NEtwork of Antisynthetase Syndrome) collaborative group's cohort. Comparisons were performed first between all ARS cases and then, in the case of significance, while using anti-Jo1 positive patients as the reference group. The characteristics of triad findings were similar and the onset mainly began with a single triad finding in all groups despite some differences in overall prevalence. The "ex-novo" occurrence of triad findings was only reduced in the anti-PL12-positive cohort, however, it occurred in a clinically relevant percentage of patients (30%). Moreover, survival was not influenced by the underlying anti-aminoacyl tRNA synthetase antibodies' positivity, which confirmed that antisynthetase syndrome is a heterogeneous condition and that antibody specificity only partially influences the clinical presentation and evolution of this condition

    Distinctive insular forms of threespine stickleback (Gasterosteus aculeatus) from western Mediterranean islands

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    Neutral and adaptive variation among populations within a species is a major component of biological diversity and may be pronounced among insular populations due to geographical isolation and island specific evolutionary forces at work. Detecting and preserving potential evolutionary significant units below the species rank has become a crucial task for conservation biology. Combining genetic, phenotypic and ecological data, we investigated evolutionary patterns among the enigmatic threespine stickleback populations from western Mediterranean islands, all of which are threatened by habitat deterioration and climate change. We find indications that these populations derive from different genetic lineages, being genetically highly distinct from the stickleback of mainland Europe and the northern Atlantic as well as from each other. Mediterranean island stickleback populations are also phenotypically distinct from mainland populations but interestingly stickleback from Iceland have converged on a similar phenotype. This distinctive island stickleback phenotype seems to be driven by distinct selective regimes on islands versus continents. Overall, our results reveal the status of western Mediterranean island stickleback as evolutionarily distinct units, important for conservation of biodiversity

    Why Should We Preserve Fishless High Mountain Lakes?

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    High mountain lakes are originally fishless, although many have had introductions of non-native fish species, predominantly trout, and recently also minnows introduced by fishermen that use them as live bait. The extent of these introductions is general and substantial often involving many lakes over mountain ranges. Predation on native fauna by introduced fish involves profound ecological changes since fish occupy a higher trophic level that was previously inexistent. Fish predation produces a drastic reduction or elimination of autochthonous animal groups, such as amphibians and large macroinvertebrates in the littoral, and crustaceans in the plankton. These strong effects raise concerns for the conservation of high mountain lakes. In terms of individual species, those adapted to live in larger lakes have suffered a higher decrease in the size of their metapopulation. This ecological problem is discussed from a European perspective providing examples from two study areas: the Pyrenees and the Western Italian Alps. Species-specific studies are urgently needed to evaluate the conservation status of the more impacted species, together with conservation measures at continental and regional scales, through regulation, and at local scale, through restoration actions, aimed to stop further invasive species expansions and to restore the present situation. At different high mountain areas of the world, there have been restoration projects aiming to return lakes to their native fish-free status. In these areas autochthonous species that disappeared with the introduction of fish are progressively recovering their initial distribution when nearby fish-free lakes and ponds are available

    Hydrologie et géochimie isotopique

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    La discipline nommée "hydrologie isotopique" est considérée du point de vue de la section d'Hydrologie isotopique de l'Agence internationale de l'énergie atomique de Vienne. La section, formée dans les années cinquante, s'occupe, entre autres, de l'avancement scientifique de cette discipline. Le rôle de l'Agence dans le domaine de l'hydrologie isotopique a toujours été double : d'une part, la section est, comme par le passé, fortement engagée dans le soutien et la coordination des progrès méthodologiques en hydrologie isotopique ; d'autre part, elle agit à l'interface entre les développements méthodologiques dans les instituts de recherche et les applications sur le terrain dans les programmes concernant l'évaluation et la gestion des ressources en eau. Ce mémoire présente une brève revue des applications des méthodes isotopiques en hydrologie, en mettant l'accent sur les nouvelles tendances et les défis occasionnés par les répercussions croissantes des activités humaines sur le cycle de l'eau. Ce travail constitue un hommage à la mémoire de Jean-Charles Fontes, ancien directeur de la section d'Hydrologie isotopique de l'AIEA, auquel nous tous devons beaucoup. (Résumé d'auteur

    Evaluation of continuous water vapor δD and &delta;<sup>18</sup>O measurements by off-axis integrated cavity output spectroscopy

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    Recent commercially available laser spectroscopy systems enabled us to continuously and reliably measure the δD and &delta;<sup>18</sup>O of atmospheric water vapor. The use of this new technology is becoming popular because of its advantages over the conventional approach based on cold trap collection. These advantages include much higher temporal resolution/continuous monitoring and the ability to make direct measurements of both isotopes in the field. Here, we evaluate the accuracy and precision of the laser based water vapor isotope instrument through a comparison of measurements with those found using the conventional cold trap method. A commercially available water vapor isotope analyzer (WVIA) with the vaporization system of a liquid water standard (Water Vapor Isotope Standard Source, WVISS) from Los Gatos Research (LGR) Inc. was used for this study. We found that the WVIA instrument can provide accurate results if (1) correction is applied for time-dependent isotope drift, (2) normalization to the VSMOW/SLAP scale is implemented, and (3) the water vapor concentration dependence of the isotopic ratio is also corrected. In addition, since the isotopic value of water vapor generated by the WVISS is also dependent on the concentration of water vapor, this effect must be considered to determine the true water vapor concentration effect on the resulting isotope measurement. <br><br> To test our calibration procedure, continuous water vapor isotope measurements using both a laser instrument and a cold trap system were carried out at the IAEA Isotope Hydrology Laboratory in Vienna from August to December 2011. The calibrated isotopic values measured using the WVIA agree well with those obtained via the cold trap method. The standard deviation of the isotopic difference between both methods is about 1.4&permil; for δD and 0.28&permil; for &delta;<sup>18</sup>O. This precision allowed us to obtain reliable values for <i>d</i>-excess. The day-to-day variation of <i>d</i>-excess measured by WVIA also agrees well with that found using the cold trap method. These results demonstrate that a coupled system, using commercially available WVIA and WVISS instruments can provide continuous and accurate isotope data, with results achieved similar to those obtained using the conventional method, but with drastically improved temporal resolution

    Enviromental isotopic composition of groundwater in the Sistema Central range (Alberche river basin)

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    The results of isotopic analyses - deuterium , oxygen-18 and tritium - are discussed for ground water samples obtained from severals wells and springs with different chemical types, located in the crystalline basin of the Alberche river. The results agree with the hypothesis that both saline and C03H-Na with reduced forms of sulphur waters can be related with medium or regional flows of meteoric waters in the cristalline body and the same can be interpreted from their tritium contents. There are not enough data to dismiss other source
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