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Mercosur has survived several crises by resorting to presidential diplomacy, but it risks becoming an empty shell unless member states work to coordinate macroeconomic policies. Its survival depends on the outcome of domestic political struggles in Brazil and Argentina and on the harmonization of exchange-rate policies between the two countries. This article examines the Argentine-Brazilian “trade wars” provoked by successive devaluations of the Brazilian currency, aggravated in 2001 by the Argentine economic crisis. The social explosion in Argentina in December 2001 showed that domestic actors can successfully challenge proglobalization policies. To consolidate, Mercosur will have to address the democratic deficit while building supranational institutions and an effective dispute-settlement system.
The aim of this study was to investigate the effects of acylated ghrelin supplementation during in vitro maturation (IVM) of bovine oocytes. IVM medium was supplemented with 20, 40 or 60 pM acylated ghrelin concentrations. Cumulus expansion area and oocyte nuclear maturation were studied as maturation parameters. Cumulus–oocyte complexes (COC) were assessed with the comet, apoptosis and viability assays. The in vitro effects of acylated ghrelin on embryo developmental capacity and embryo quality were also evaluated. Results demonstrated that acylated ghrelin did not affect oocyte nuclear maturation and cumulus expansion area. However, it induced cumulus cell (CC) death, apoptosis and DNA damage. The damage increased as a function of the concentration employed. Additionally, the percentages of blastocyst yield, hatching and embryo quality decreased with all acylated ghrelin concentrations tested. Our study highlights the importance of acylated ghrelin in bovine reproduction, suggesting that this metabolic hormone could function as a signal that prevents the progress to reproductive processes.
A new genus and species of megalonychid sloth, Zacatzontli tecolotlanensis n. gen. n. sp., is described from the late Hemphillian of Jalisco, Mexico. Comparison and analysis of the type specimen, a mandible, with other megalonychid sloths shows a closer relationship to South American taxa than those from North America or the Caribbean. This suggests that during the early stages of the Great American Biotic Interchange there were two separate dispersal events of megalonychid sloths—an earlier one represented by Pliometanastes and the later one by Zacatzontli n. gen. While the morphology of the spout of Zacatzontli more closely resembles that of Megalonyx, based on the current record, Zacatzontli does does not enter North America until after the evolution of Megalonyx from Pliometanastes. The role of the northern neotropics in South America as a staging area for South American taxa that entered North America is discussed.
The importance of pork in the transmission of Salmonella spp. to humans has led to the development of control programmes worldwide. For this, knowledge on the epidemiology of the infection in the production system is fundamental to the efficacy of the regulations. Our objective was to determine the prevalence and spatial distribution of Salmonella-infected farms in the central region of Argentina, and to identify the predominant serotypes and epidemiological factors associated with an increased risk of infection. Salmonella was isolated from 22 of 52 sampled farms, for a farm prevalence of 42·3% (95% confidence interval 28·4–56·1). The most frequent serotypes isolated were S. Typhimurium and S. Derby, which have often been considered of public health concern in the region. Limited evidences of global and local clustering in the region under study were found, and the type of feed and presence of diarrhoeic pigs were significantly associated with having Salmonella shedders in the farm. This highlights the need to evaluate microbiological controls at the farm level, and demonstrates the usefulness of the spatial tools to identify areas of greatest risk when processing pork at slaughterhouse, which could contribute to increasing the food safety of pork products.
Understanding the processes that shape parasite diversification, their distribution and abundance provides valuable information on the dynamics and evolution of disease. In this study, we assessed the diversity, distribution, host-specificity and infection patterns of apicomplexan parasites in amphibians and reptiles from Oman, Arabia. Using a quantitative PCR approach we detected three apicomplexan parasites (haemogregarines, lankesterellids and sarcocystids). A total of 13 haemogregarine haplotypes were identified, which fell into four main clades in a phylogenetic framework. Phylogenetic analysis of six new lankesterellid haplotypes revealed that these parasites were distinct from, but phylogenetically related to, known Lankesterella species and might represent new taxa. The percentage of infected hosts (prevalence) and the number of haemogregarines in the blood (parasitaemia) varied significantly between gecko species. We also found significant differences in parasitaemia between haemogregarine parasite lineages (defined by phylogenetic clustering of haplotypes), suggesting differences in host–parasite compatibility between these lineages. For Pristurus rupestris, we found significant differences in haemogregarine prevalence between geographical areas. Our results suggest that host ecology and host relatedness may influence haemogregarine distributions and, more generally, highlight the importance of screening wild hosts from remote regions to provide new insights into parasite diversity.
The LMC is being surveyed in the Hα emission line with a scanning Fabry-Perot interferometer, attached to the 36 cm telescope of the Observatoire de Marseille. The present results concern the kinematical mapping of bright nebulae; it shows that the kinetic energy involved in the gas motion is closely related to the evolutionary stage of the embedded stars. In particular, in the 30 Dor nebula, a few one-peaked line profiles remain at the boundaries of the shells, among the numerous split areas. The 50-100 pc shells exhibit a relatively usual spherical expansion, with velocities in the same range at the boundaries. On the contrary, the 10-20 pc shells of the central core show different velocities of the one-peak sides of the shells.
La nébuleuse planétaire ayant le plus grand diamètre apparent est la nébuleuse Helix; elle se prête très bien, en raison de ses larges dimensions (15′ × 10′), aux observations avec les techniques interférentielles courantes: la photographie monochromatique en lumière Hα ou [NII] λ6584 et l'interférométrie Perot-Fabry. On peut ainsi obtenir non seulement la morphologie de cette nébuleuse, mais aussi le champ des vitesses radiales au moyen des anneaux d'interférence des mêmes raies (Courtès, 1951, 1952, 1960).
This paper outlines several outreach initiatives that the Proyecto de Investigación Arqueológico Regional Ancash (PIARA) established to address the challenges of heritage preservation at the prehistoric archaeological site and rural community of Hualcayán, located in rural highland Ancash, Peru. We discuss three projects—a heritage festival, a textile enterprise, and an oral history project—that were designed and executed through a collaboration between PIARA and the Hualcayán community. We find that these “co-creative” projects encourage local stakeholders to discover and define for themselves the value of both their ancient and modern heritage. Reflecting on the outcomes from these projects, we discuss the co-creative approach as an effective strategy for improving the preservation of archaeological remains and enhancing the livelihood of the modern community.
A retrospective case-control study of patients who had undergone cataract extraction at a Spanish hospital over a 13-year period was conducted to identify the risk factors for developing post-operative endophthalmitis (POE). During the study period, the type of antibiotic prophylaxis was changed from subconjunctival gentamicin to the addition of both vancomycin and gentamicin to the irrigating solution. The overall incidence of POE was 0·19% (35 cases/18 287 operations). For the period prior to the change in antibiotic prophylaxis, the incidence rate of POE was 3·4 cases/1000 operations while in the latter period the incidence rate decreased to 0·34 cases/1000 operations. All patients who presented a virulent microorganism had a final visual acuity worse than 20/200. The only significant risk factor identified was the type of prophylaxis used (odds ratio 1·97, 95% confidence interval 0·94–4·14, P = 0·07). There were no significant differences between cases and controls although choice of surgeon approached significance.
Cape Verde has a higher number of reptile taxa and endemics than any of the five archipelagos in the Macaronesian region. Mapping the precise distributions and assessing the conservation status of reptiles is the first step towards effective conservation. Presence/absence and abundance data were gathered from extensive fieldwork and post-1980 literature. Evaluation of conservation status was considered at specific and subspecific levels, following IUCN Red List criteria and using RAMAS. Fieldwork confirmed the occurrence of 34 of 37 previously recorded taxa (31 native, three exotic). One taxon continues to be considered Extinct. Three broad distribution and rarity patterns were identified: widespread and abundant taxa occurring on ≥ 2 islands/islets, widespread or abundant taxa restricted to one island, and rare or limited range taxa occurring on small areas of islands or islets. More than a third of taxa have areas of occupancy < 20 km2 and extents of occurrence < 100 km2. Geckos are rarer than skinks because of their high habitat specialization, with 58% occurring on only one island/islet. About half of all taxa are potentially threatened, twice the proportion of those in the Canary Islands, a difference that could be explained by the smaller area and greater aridity of the Cape Verde islands. The criterion used for most threat categorizations is geographical range, and the most pervasive threats are natural disasters, intrinsic factors of the species and introduced species. The importance of applying conservation status at the subspecific level to island endemics is emphasized. Several conservation measures are proposed, including optimized design of protected areas.
Corrosion tests of Zircaloy-4 were performed in a dilute NaOH solution (pH =12.5) at 303 K for 90 days using the gas flow system (oxygen; < 1 ppb) and a batch method (oxygen; < 0.1 ppm). The corrosion rate was determined by measuring gaseous hydrogen and the hydrogen absorbed into Zircaloy-4 assuming the following reaction:
where x represents the Zircaloy-4 hydrogen absorption ratio. The initial hydrogen content in the Zircaloy-4 specimen was controlled to be below 10 ppm. The corrosion rate decreased with time (90-day values: 2.46×10-3 and 2.37×10-3 μm/y for the gas flow method and 6.72×10-2 μm/y for the batch test). The Zircaloy-4 hydrogen absorption ratio during corrosion was over 90%. The large amount of hydrogen absorbed in Zircaloy-4 will play an important role in the long-term safety for the disposal of irradiated Zircaloy materials.
In many countries, regulations for the management of nuclear waste require a performance (safety/risk) assessment to demonstrate the safety asserted to be provided by the sites/facilities proposed for handling, storing, and disposing of the wastes. However performance assessment can play a bigger role than solely demonstration of compliance with applicable safety standards in support of a regulatory decision (i.e., licensing of a waste management facility). Performance assessment can be an effective management tool during all phases of a waste management program: from development of national nuclear waste management policies; to programmatic environmental impact assessments associated with design and siting evaluations, site selection, and site characterization; to licensing and operation of facilities.
International experience has demonstrated that nuclear waste management programs are long-term efforts, lasting at least two to three decades from initial policy development to licensing and commencement of waste management and disposal operations. This experience has also demonstrated that consistent attention to, and integration of, initial component studies are necessary to provide a comprehensive total system analysis for programmatic environmental impact assessments and for licensing.
For nearly 40 years, Sandia National Laboratories has developed and applied a performance assessment methodology in numerous national and international nuclear waste management programs. These applications range from development and feasibility testing of environmental health standards to preliminary evaluation of waste disposal sites; to establishing the basis for demonstration of compliance; to informing licensing (compliance demonstration) decisions. In many of these applications the performance assessment methodology has also served as a management tool for confirming the added value of research and development investments.
This paper presents examples to illustrate how performance assessment has been used as an effective management tool through multiple phases of a nuclear waste management program.
During irradiation in the reactor, a fraction of the fission product inventory will have segregated either to the gap between the fuel and the cladding or to the grain boundaries in the fuel. Of these nuclides, the behavior of the fission gases is best known. The part of the inventory that is rapidly released upon contact with water is designated the instant release fraction (IRF). Previous studies have shown that IRF and fission gas release (FGR) seem to be correlated. Studies of the instant release fraction from high burnup fuel is of interest for the assessment of the safety of a geological repository.
The instant release fractions of 129I and 137Cs from five different light water reactor (LWR) fuel rods with a burnup range of 43 to 75 MWd/kgU and a fission gas release range from 0.9 to 5.0 % were studied. Four types of fuel samples (pellet, fragment, powder and fuel rodlet) have been used in the experiments. The results show that the fuel sample preparation method has a significant impact on the release from high burnup fuel samples over the time period covered by this study. Leaching of high burnup fuel samples with fuel detached from the cladding shows the highest release. The fractional 129I release from such fragment samples is similar to the FGR in the corresponding rod. On the other hand, corresponding fractional release of 137Cs is lower.
In order to observe the structural change in the interior of irradiated fuel assembly, the non-destructive post irradiation examination technique using X-ray computer tomography (X-ray CT) was developed.
In this X-ray CT system, the 12 MeV X-ray pulses were used in synchronization with the switch-in of the detector in order to minimize the effects of the gamma ray emissions from the irradiated fuel assembly then clear cross section CT image of irradiated fuel assembly could be successfully obtained. Also, this non-destructive technique can be applied to observe the inner condition of the high radioactive materials such as a radioactive waste.