117 research outputs found

    Platygonus sp. (Mammalia: Tayassuidae) in Uruguay (Raigón? Formation; Pliocene–early Pleistocene), comments about its distribution and palaeoenvironmental significance in South America

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    This study provides the first record of Platygonus in Uruguay (Raigón? Formation, Pliocene–early Pleistocene; Canelones Department). The allocation to the Raigón Formation is tentative because the remains were found in a drill core. It is the oldest record of a tayassuid in Uruguay. The following morphological features clearly indicate that it belongs to Platygonus: simple premolars that are bicuspid, bunolophodont, mesodont and with an enamel cingulum surrounding the entire tooth. This is one of the largest forms among North American and South American Platygonus. The record of Platygonus in the Raigón Formation suggests arid or semi-arid climates, and, as do some associated birds and mammals, open or relatively open environments. A significant level of specific diversity of Platygonus in South America is recognized during the late Pliocene with the lowest diversity occurring during the early–middle Pleistocene.Fil: Gasparini, Germán Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ubilla, M.. Universidad del Uruguay. Facultad de Ciencias; Urugua

    Characterising the Didactic-Stochastic Knowledge of Future Mathematics Teachers: The Case of Chile

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    Background: Stochastics’ teacher education has become an important research topic since mathematics teachers are usually responsible for the teaching of stochastics (statistics and probability) in schools. However, the emergence of new theoretical approaches has resulted in the identification of a problem: organizing and describing the necessary professional knowledge to teach stochastics. Objectives: The aim of this research is to characterize the didactic-stochastic knowledge needed for pre-service mathematics teachers, considering Chile as a case study. Design: Following a qualitative perspective, through a content-analysis. Setting and Participants: The Pedagogical and Disciplinary Standards for Mathematics Teaching Programs. Data collection and analysis: The national guidelines on the stochastic education of pre-service’ teachers were analysed to collect text fragments describing professional knowledge expected in pre-service teachers. Results: We obtained a set of 37 indicators organized according to the Didactic-Mathematical Knowledge Model, which includes disciplinary aspects (stochastic content), the knowledge of students and their learning (cognitive content) and interests (affective content), instruction processes (interactional and mediational content) and their link with the educational context and other knowledge areas (ecological content). Conclusions: We hope that the identified indicators become a useful tool to organize and evaluate stochastic education programs for pre- and in-service teachers. Moreover, we highlight the replicability of the method uses and the possible adaptation of results to other educational contexts

    Hippidioll sp. (Mammalia, Perissodactyla. Equidae) en sedimentos del Pleistoceno superior del Uruguay (Edad Mamífero Lujanense)

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    The most complete remains of Hippidion sp. to the Pleistocene of Uruguay are described. They agree with a robust form with fore limbs relatively short to the large skull. Cranial, mandibles and postcranial characters are analized and compared with respect to others «hippidiformes» of South America. The depositional environment belong to floodplain facies of meandering fluvial systems.Se describen los restos más completos de Hippidion sp. reportados hasta el momento para el Pleistoceno de Uruguay. Corresponden a una forma robusta con extremidades anteriores relativamente cortas respecto del cráneo grande. Se analizan sus caracteres cráneo-mandibulares y postcraneales comparados con otros «hippidiformes» de Sudamérica. El marco sedimentario corresponde a una planicie de inundación de un sistema fluvial meandriforme de la Fm. Sopas (Pleistoceno superior; Edad mamífero Lujanense) del Uruguay

    Trasplante de homoinjertos valvulares cardiacos y vasculares

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    The advances in the manipulation of human tissues, the development of cryobiology, paediatric cardiac surgery, the impossibility of obtaining an ideal prosthetic cardiac valve and the surgical treatment of cardiovascular infections have revived interest in the use of homografts. The donors of these homografts can be: a) Live donors: aortic and pulmonary valve of the recipient of a heart transplant; b) Multiorgan donors with a diagnosis of death according to neurological criteria, whose heart is rejected for heart transplant; c) Cadaver donors with asystolia of less than 8 hours. Homograft cardiac valves are the substitute of choice in aortic valve endocarditis, patients with counter-indications for anticoagulation, reconstruction of the outflow tract of the right ventricle, aortic valve replacement in children and young adults through the Ross operation, and an optional indication is the aortic valve and/or rising aorta replacement in patients over 60 years of age. Although there are not sufficiently broad series of homogratfs with arterial substitutes, with respect to the number of patients and time of evolution, the results suggest that this can benefit patients with vascular infection, immunodepressed patients or complex patients whose technique during the operation might require a homograft

    Dual-source CT for visualization of the coronary arteries in heart transplant patients with high heart rates

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    OBJECTIVE. The purpose of this study was to evaluate the quality of dual-source CT images of the coronary arteries in heart transplant recipients with high heart rates. SUBJECTS AND METHODS. Contrast-enhanced dual-source CT coronary angiography was performed on 23 heart transplant recipients (20 men, three women; mean age, 61.1 ± 12.8 years). Data sets were reconstructed in 5% steps from 30% to 80% of the R-R interval. Two blinded independent readers using a 5-point scale (0, not evaluative; 4, excellent quality) assessed the quality of images of coronary segments. RESULTS. The mean heart rate during scanning was 89.2 ± 10.4 beats/min. Interobserver agreement on the quality of images of the whole coronary tree was a kappa value of 0.78 and for selection of the optimal reconstruction interval was a kappa value of 0.82. The optimal reconstruction interval was systole in 17 (74%) of the 23 of heart transplant recipients. At the best reconstruction interval, diagnostic image quality (score ≥ 2) was obtained in 92.1% (303 of 329) of the coronary artery segments. The mean image quality score for the whole coronary tree was 3.1 ± 1.01. No significant correlation between mean heart rate (ρ = 0.31) or heart rate variability (ρ = 0.23) and overall image quality score was observed (p = not significant). CONCLUSION. Dual-source CT acquisition yields coronary angiograms of diagnostic quality in heart transplant recipients. Mean heart rate and heart rate variability during scanning do not have a negative effect on the overall quality of images of the coronary arteries

    Trasplante cardíaco

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    A heart transplant is at present considered the treatment of choice in cases of terminal cardiac insufficiency refractory to medical or surgical treatment. Due to factors such as the greater life expectancy of the population and the more efficient management of acute coronary syndromes, there is an increasing number of people who suffer from heart failure. It is estimated that the prevalence of the disease in developed countries is around 1%; of this figure, some 10% are in an advanced stage and are thus potential receptors of a heart transplant. The problem is that it is still not possible to offer this therapeutic form to all of the patients that require it. Consequently, it is necessary to optimise the results of the heart transplant through the selection of patients, selection and management of donors, perioperative management and control of the disease due to graft rejection. Since the first transplant carried out in 1967, numerous advances and changes have taken place, which has made it possible to increase survival and quality of life of those who have received a new heart. In this article we review the most relevant aspects of the heart transplant and the challenges that are currently faced

    Mitochondrial phylogeography and demographic history of the Vicuña: implications for conservation

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    The vicuña (Vicugna vicugna; Miller, 1924) is a conservation success story, having recovered from near extinction in the 1960s to current population levels estimated at 275 000. However, lack of information about its demographic history and genetic diversity has limited both our understanding of its recovery and the development of science-based conservation measures. To examine the evolution and recent demographic history of the vicuña across its current range and to assess its genetic variation and population structure, we sequenced mitochondrial DNA from the control region (CR) for 261 individuals from 29 populations across Peru, Chile and Argentina. Our results suggest that populations currently designated as Vicugna vicugna vicugna and Vicugna vicugna mensalis comprise separate mitochondrial lineages. The current population distribution appears to be the result of a recent demographic expansion associated with the last major glacial event of the Pleistocene in the northern (18 to 22°S) dry Andes 14–12 000 years ago and the establishment of an extremely arid belt known as the 'Dry Diagonal' to 29°S. Within the Dry Diagonal, small populations of V. v. vicugna appear to have survived showing the genetic signature of demographic isolation, whereas to the north V. v. mensalis populations underwent a rapid demographic expansion before recent anthropogenic impacts

    Inequalities in health care use and expenditures: empirical data from eight developing countries and countries in transition

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    This paper summarizes eight country studies of inequality in the health sector. The analyses use household data to examine the distribution of service use and health expenditures. Each study divides the population into "income" quintiles, estimated using consumption expenditures. The studies measure inequality in the use of and spending on health services. Richer groups are found to have a higher probability of obtaining care when sick, to be more likely to be seen by a doctor, and to have a higher probability of receiving medicines when they are ill, than the poorer groups. The richer also spend more in absolute terms on care. In several instances there are unexpected findings. There is no consistent pattern in the use of private providers. Richer households do not devote a consistently higher percentage of their consumption expenditures to health care. The analyses indicate that intuition concerning inequalities could result in misguided decisions. It would thus be worthwhile to measure inequality to inform policy-making. Additional research could be performed using a common methodology for the collection of data and applying more sophisticated analytical techniques. These analyses could be used to measure the impact of health policy changes on inequality

    Effects of parity order and reproductive management on the efficiency of rabbit productive systems.

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    The aim of this work was to study the effect of parity order and reproductive management systems on rabbit production performance. A total of 73 rabbit does (I group) were submitted to a 35-day intensive rhythm [artificial insemination (AI) on day 4 post-partum (pp) and weaning at 25 days of lactation], and 108 rabbit does (SI group) were submitted to a 42-day semi-intensive rhythm (AI on day 11 pp and weaning at 35 days of lactation) during 9 months. Primiparous does had the lowest live body weight at parturition (P < 0.0001) and at 21 days of lactation (P < 0.0001). They also had lower milk production (P < 0.0001) than does with later parities. I group animals needed a higher number of AI than SI group to become pregnant (1.70 ± 0.03 vs. 1.39 ± 0.03; P < 0.0001: especially after the third). Prolificacy was not affected by the management system. Parturition interval (PI) was longer than expected in both groups [56.0 ± 1.4 and 50.9 ± 1.38 days in I and SI groups, respectively (P < 0.05)]. Mean productivity, estimated as number of weaned rabbits per female and year, was 12 kits higher in rabbit does of the SI group (P < 0.05). From the third parturition onward, an increase in live body weight of kits at different ages was observed. At 21 (P < 0.05) and 25 days of age (P < 0.01), kits from the I group rabbit does weighed more than those from the SI group; however, the latter showed a higher weight at 35 (P < 0.05) and 60 days of age (P < 0.05). Rabbit does with two or three parturitions had higher litter size at 21 and 25 days of age (P < 0.0001 and P < 0.001, respectively). Kit mortality between 21 and 25 days of age and between 35 and 60 days of age was not affected by treatments but was higher in the I group between 25 and 35 days (18.2 vs. 5.03% in the I and SI groups, respectively; P < 0.0001) and as age of does increased (P < 0.05). In light of these results, we could conclude that long term doe reproductive performance is negatively affected and litter viability decreased when using intensive compared to a semi-intensive reproductive management

    HLA-DRB1 association with Henoch-Schonlein purpura

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    Objective: Henoch-Schönlein purpura (HSP) is the most common vasculitis in children but it is not exceptional in adults. Increased familial occurrence supports a genetic predisposition for HSP. In this context, an association with the human leukocyte antigen-HLA-DRB1*01 phenotype has been suggested in Caucasian individuals with HSP. However, data on the potential association of HSP with HLA-DRB1*01 were based on small case series. To further investigate this issue, we performed HLA-DRB1 genotyping of the largest series of HSP patients ever assessed for genetic studies in Caucasians. Methods: 342 Spanish patients diagnosed with HSP fulfilling the American College of Rheumatology and the Michel et al classification criteria, and 303 sex and ethnically matched controls were assessed. HLA-DRB1 alleles were determined using a PCR-Sequence-Specific-Oligonucleotide Probe (PCR-SSOP) method. Results: A statistically significant increase of HLA-DRB1*01 in HSP patients when compared with controls was found (43% vs 7%, respectively; p<0.001; odds ratio-OR=2.03 [1.43-2.87]). It was due to the increased frequency of HLA-DRB1*0103 phenotype in HSP (14% vs 2%; p<0.001; OR=8.27 [3.46-23.9]). These results remained statistically significant after adjusting for Bonferroni correction. In contrast, a statistically significant decreased frequency of the HLA-DRB1*0301 phenotype was observed in patients compared to controls (5.6% vs 18.1%, respectively; p<0.001, OR=0.26 [0.14-0.47]), even after adjustment for Bonferroni correction. No HLA-DRB1 association with specific features of the disease was found. Conclusion: Our study confirms an association of HSP with HLA-DRB1*01 in Caucasians. Also, a protective effect against the development of HSP appears to exist in Caucasians carrying the HLA-DRB1*03 phenotype
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