Medición del flujo de neutrones a 10,6 Gv

Se analizan los registros obtenidos en una serie de cuatro vuelos con globos dilatables, que alcanzaron una altura máxima equivalente a una presión de 12 mb. Los lanzamientos fueron realizados en Buenos Aires. Los equipos transportados constaban de un contador enriquecido y otro normal, rodeados de 2,5 cm de parafina y 0,5 mm de Cd.; sistema sensible a neutrones en el rango de energías de aproximadamente 0,01 a 1 Mev. La posición del máximo de transición, a 10,6 Gv, fue 98 ± 3 mb; valor que concuerda con el esperado, de acuerdo con la variación en latitud predicha por Lingenfelter y con los resultados experimentales obtenidos por Holt, Mendell y Korff. El contaje al tope de la atmósfera fue estimado por extrapolación, representando aproximadamente un 33 °/o del contaje máximo; valor muy alto si se compara con el obtenido en otros trabajos.This paper presents an analysis of the records obtained during a series of four flights, carried out by means of expandible balloons, which reached a maximum altitude equivalent to a 12 mb pressure. The launching took place at Buenos Aires. The transported equipment was constituted by one enriched counter and one normal surrounded by 2,5 cm of paraffin and 0,5 mm of. Cd. The system was sensitive to neutrons within the energy range of 0,01 to 1 Mev. The position of the maximum transition at 10,6 Gv was 98 ± 3 mb., value which agrees with the one expected according to the variation in latitude predicted by Lingelfelter and with the experimental results obtained by Holt, Mendell and Korff. The counting on top of the atmosphere was estimated trough extrapolation, representing roughly a 33°/o of the maximum counting. This is a very high value compared to the ones obtained in other works.Asociación Argentina de Geofísicos y Geodesta

Medición del flujo de neutrones a 10,6 Gv

Se analizan los registros obtenidos en una serie de cuatro vuelos con globos dilatables, que alcanzaron una altura máxima equivalente a una presión de 12 mb. Los lanzamientos fueron realizados en Buenos Aires. Los equipos transportados constaban de un contador enriquecido y otro normal, rodeados de 2,5 cm de parafina y 0,5 mm de Cd.; sistema sensible a neutrones en el rango de energías de aproximadamente 0,01 a 1 Mev. La posición del máximo de transición, a 10,6 Gv, fue 98 ± 3 mb; valor que concuerda con el esperado, de acuerdo con la variación en latitud predicha por Lingenfelter y con los resultados experimentales obtenidos por Holt, Mendell y Korff. El contaje al tope de la atmósfera fue estimado por extrapolación, representando aproximadamente un 33 °/o del contaje máximo; valor muy alto si se compara con el obtenido en otros trabajos.This paper presents an analysis of the records obtained during a series of four flights, carried out by means of expandible balloons, which reached a maximum altitude equivalent to a 12 mb pressure. The launching took place at Buenos Aires. The transported equipment was constituted by one enriched counter and one normal surrounded by 2,5 cm of paraffin and 0,5 mm of. Cd. The system was sensitive to neutrons within the energy range of 0,01 to 1 Mev. The position of the maximum transition at 10,6 Gv was 98 ± 3 mb., value which agrees with the one expected according to the variation in latitude predicted by Lingelfelter and with the experimental results obtained by Holt, Mendell and Korff. The counting on top of the atmosphere was estimated trough extrapolation, representing roughly a 33°/o of the maximum counting. This is a very high value compared to the ones obtained in other works.Asociación Argentina de Geofísicos y Geodesta

Performance and precision of double digestion RAD (ddRAD) genotyping in large multiplexed datasets of marine fish species

The development of Genotyping-By-Sequencing (GBS) technologies enables cost-effective analysis of large numbers of Single Nucleotide Polymorphisms (SNPs), especially in “non-model” species. Nevertheless, as such technologies enter a mature phase, biases and errors inherent to GBS are becoming evident. Here, we evaluated the performance of double digest Restriction enzyme Associated DNA (ddRAD) sequencing in SNP genotyping studies including high number of samples. Datasets of sequence data were generated from three marine teleost species (>5500 samples, >2.5 × 1012 bases in total), using a standardized protocol. A common bioinformatics pipeline based on STACKS was established, with and without the use of a reference genome. We performed analyses throughout the production and analysis of ddRAD data in order to explore (i) the loss of information due to heterogeneous raw read number across samples; (ii) the discrepancy between expected and observed tag length and coverage; (iii) the performances of reference based vs. de novo approaches; (iv) the sources of potential genotyping errors of the library preparation/bioinformatics protocol, by comparing technical replicates. Our results showed use of a reference genome and a posteriori genotype correction improved genotyping precision. Individual read coverage was a key variable for reproducibility; variance in sequencing depth between loci in the same individual was also identified as an important factor and found to correlate to tag length. A comparison of downstream analysis carried out with ddRAD vs single SNP allele specific assay genotypes provided information about the levels of genotyping imprecision that can have a significant impact on allele frequency estimations and population assignment. The results and insights presented here will help to select and improve approaches to the analysis of large datasets based on RAD-like methodologies

Hypertrophic cardiomyopathy: two homozygous cases with "typical" hypertrophic cardiomyopathy and three new mutations in cases with progression to dilated cardiomyopathy

About 10% of cases of hypertrophic cardiomyopathy (HCM) evolve into dilated cardiomyopathy (DCM) with unknown causes. We studied 11 unrelated patients (pts) with HCM who progressed to DCM (group A) and 11 who showed "typical" HCM (group B). Mutational analysis of the beta-myosin heavy chain (MYH7), myosin-binding protein C (MYBPC3), and cardiac troponin T (TNNT2) genes demonstrated eight mutations affecting MYH7 or MYBPC3 gene, five of which were new mutations. In group A-pts, the first new mutation occurred in the myosin head-rod junction and the second occurred in the light chain-binding site. The third new mutation leads to a MYBPC3 lacking titin and myosin binding sites. In group B, two pts with severe HCM carried two homozygous MYBPC3 mutations and one with moderate hypertrophy was a compound heterozygous for MYBPC3 gene. We identified five unreported mutations, potentially "malignant" defects as for the associated phenotypes, but no specific mutations of HCM/DCM

Microbial dynamics during shelf-life of industrial Ricotta cheese and identification of a Bacillus strain as a cause of a pink discolouration

Dairy products are perishable and have to be preserved from spoilage during the food chain to achieve the desired shelf-life. Ricotta is a typical Italian soft dairy food produced by heat coagulation of whey proteins and is considered to be a light and healthy product. The shelf-life of Ricotta could be extended, as required by the international food trade market; however, heat resistant microflora causes spoilage and poses issues regarding the safety of the product. Next-generation sequencing (NGS) applied to the Ricotta samples defined the composition of the microbial community in-depth during the shelf-life. The analysis demonstrated the predominance of spore-forming bacteria throughout the shelf-life, mostly belonging to Bacillus, Paenibacillus and Clostridium genera. A strain involved in spoilage and causing a pink discolouration of Ricotta was isolated and characterised as Bacillus mycoides/weihenstephanensis. This is the first report of a food discolouration caused by a toxigenic strain belonging to the Bacillus cereus group that resulted the predominant strain in the community of the defective ricotta. These results suggest that the processing of raw materials to eliminate spores and residual microflora could be essential for improving the quality and the safety of the product and to extend the shelf-life of industrial Ricotta