683 research outputs found

    StoRM: A Manager for Storage Resource in Grid

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    Nowadays, data intensive applications demand high-performance and large-storage systems capable of serving up to various Petabytes of storage space. Therefore, common solutions adopted in data centres include Storage Area Networks (SAN) and cluster parallel file systems, such as GPFS from IBM and Lustre from Sun Microsystems. In order to make these storage system solutions available in modern Data Grid architectures, standard interfaces are needed. The Grid Storage Resource Manager (SRM) interface is one of these standard interfaces. Grid storage services implementing the SRM standard provide common capabilities and advanced functionality such as dynamic space allocation and file management on shared storage systems. In this paper, we describe StoRM (STOrage Resource Manager). StoRM is a flexible and high-performing implementation of the standard SRM interface version 2.2. The software architecture of StoRM allows for an easy integration to different underlying storage systems via a plug-in mechanism. In particular, StoRM takes advantage from storage systems based on cluster file systems. Currently, StoRM is installed and used in production in various data centres, including the WLCG Italian Tier-1. In addition, Economics and Financial communities, as represented by the EGRID Project, adopt StoRM in production as well

    Mitochondrial selfish elements and the evolution of biological novelties.

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    We report the present knowledge about RPHM21, a novel male-specific mitochondrial protein with a putative role in the paternal inheritance of sperm mitochondria in the Manila clam Ruditapes philippinarum, a species with doubly uniparental inheritance of mitochondria (DUI). We review all the available data on rphm21 transcription and translation, analyze in detail its female counterpart, RPHF22, discuss the homology with RPHM21, the putative function and origin, and analyze their polymorphism. The available evidence is compatible with a viral origin of RPHM21 and supports its activity during spermatogenesis. RPHM21 is progressively accumulated in mitochondria and nu- clei of spermatogenic cells, and we hypothesize it can influence mitochondrial inheritance and sex- ual differentiation. We propose a testable model that describes how the acquisition of selfish fea- tures by a mitochondrial lineage might have been responsible for the emergence of DUI, and for the evolution of separate sexes (gonochorism) from hermaphroditism. The appearance of DUI most likely entailed the invasion of at least 1 selfish element, and the extant DUI systems can be seen as resolved conflicts. It was proposed that hermaphroditism was the ancestral condition of bi- valves, and a correlation between DUI and gonochorism was documented. We hypothesize that DUI might have driven the shift from hermaphroditism to gonochorism, with androdioecy as transi- tion state. The invasion of sex-ratio distorters and the evolution of suppressors can prompt rapid changes among sex-determination mechanisms, and DUI might have been responsible for one of such changes in some bivalve species. If true, DUI would represent the first animal sex-determination system involving mtDNA-encoded proteins

    A Naturally Heteroplasmic Clam Provides Clues about the Effects of Genetic Bottleneck on Paternal mtDNA

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    Mitochondrial DNA (mtDNA) is present in multiple copies within an organism. Since these copies are not identical, a single individual carries a heterogeneous population of mtDNAs, a condition known as heteroplasmy. Several factors play a role in the dynamics of the within-organism mtDNA population: among them, genetic bottlenecks, selection, and strictly maternal inheritance are known to shape the levels of heteroplasmy across mtDNAs. In Metazoa, the only evolutionarily stable exception to the strictly maternal inheritance of mitochondria is the doubly uniparental inheritance (DUI), reported in 100+ bivalve species. In DUI species, there are two highly divergent mtDNA lineages, one inherited through oocyte mitochondria (F-type) and the other through sperm mitochondria (M-type). Having both parents contributing to the mtDNA pool of the progeny makes DUI a unique system to study the dynamics of mtDNA populations. Since, in bivalves, the spermatozoon has few mitochondria (4-5), M-type mtDNA faces a tight bottleneck during embryo segregation, one of the narrowest mitochondrial bottlenecks investigated so far. Here, we analyzed the F- and M-type mtDNA variability within individuals of the DUI species Ruditapes philippinarum and investigated for the first time the effects of such a narrow bottleneck affecting mtDNA populations. As a potential consequence of this narrow bottleneck, the M-type mtDNA shows a large variability in different tissues, a condition so pronounced that it leads to genotypes from different tissues of the same individual not to cluster together. We believe that such results may help understanding the effect of low population size on mtDNA bottleneck

    Role of poultry meat in a balanced diet aimed at maintaining health and wellbeing: an Italian consensus document

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    The relationship between the consumption of meat and health is multifaceted, and it needs to be analyzed in detail, with specific attention to the relevant differences that characterize the effects of the different meat types, as yet considered by only a limited literature. A variable but moderate energy content, highly digestible proteins (with low levels of collagen) of good nutritional quality, unsaturated lipids (mainly found in the skin and easily removed), B-group vitamins (mainly thiamin, vitamin B6, and pantothenic acid), and minerals (like iron, zinc, and copper) make poultry meat a valuable food. Epidemiological studies performed across the world, in highly diverse populations with different food preferences and nutritional habits, provide solid information on the association between poultry consumption, within a balanced diet, and good health. Consumption of poultry meat, as part of a vegetable-rich diet, is associated with a risk reduction of developing overweight and obesity, cardiovascular diseases, and type 2 diabetes mellitus. Also, white meat (and poultry in particular) is considered moderately protective or neutral on cancer risk. The relevance of poultry meat for humans also has been recognized by the UN Food and Agricultural Organization (FAO), who considers this widely available, relatively inexpensive food to be particularly useful in developing countries, where it can help to meet shortfalls in essential nutrients. Moreover, poultry meat consumption also contributes to the overall quality of the diet in specific ages and conditions (prior to conception, during pregnancy up to the end of breastfeeding, during growth, and in the geriatric age) and is suitable for those who have an increased need for calorie and protein compared to the general population

    Signatures of Extreme Longevity: A Perspective from Bivalve Molecular Evolution

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    Among Metazoa, bivalves have the highest lifespan disparity, ranging from 1 to 500+ years, making them an exceptional testing ground to understand mechanisms underlying aging and the evolution of extended longevity. Nevertheless, comparative molecular evolution has been an overlooked approach in this instance. Here, we leveraged transcriptomic resources spanning 30 bivalve species to unravel the signatures of convergent molecular evolution in four long-lived species: Margaritifera margaritifera, Elliptio complanata, Lampsilis siliquoidea, and Arctica islandica (the latter represents the longest-lived noncolonial metazoan known so far). We applied a comprehensive approach-which included inference of convergent dN/dS, convergent positive selection, and convergent amino acid substitution-with a strong focus on the reduction of false positives. Genes with convergent evolution in long-lived bivalves show more physical and functional interactions to each other than expected, suggesting that they are biologically connected; this interaction network is enriched in genes for which a role in longevity has been experimentally supported in other species. This suggests that genes in the network are involved in extended longevity in bivalves and, consequently, that the mechanisms underlying extended longevity are-at least partially-shared across Metazoa. Although we believe that an integration of different genes and pathways is required for the extended longevity phenotype, we highlight the potential central roles of genes involved in cell proliferation control, translational machinery, and response to hypoxia, in lifespan extension

    Deciphering the Link between Doubly Uniparental Inheritance of mtDNA and Sex Determination in Bivalves: Clues from Comparative Transcriptomics

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    Bivalves exhibit an astonishing diversity of sexual systems and sex-determining mechanisms. They can be gonochoric, hermaphroditic or androgenetic, with both genetic and environmental factors known to determine or influence sex. One unique sex-determining system involving the mitochondrial genome has also been hypothesized to exist in bivalves with doubly uniparental inheritance (DUI) of mtDNA. However, the link between DUI and sex determination remains obscure. In this study, we performed a comparative gonad transcriptomics analysis for two DUI-possessing freshwater mussel species to better understand the mechanisms underlying sex determination and DUI in these bivalves. We used a BLAST reciprocal analysis to identify orthologs between Venustaconcha ellipsiformis and Utterbackia peninsularis and compared our results with previously published sex-specific bivalve transcriptomes to identify conserved sex-determining genes. We also compared our data with other DUI species to identify candidate genes possibly involved in the regulation of DUI. A total of 3c12,000 orthologous relationships were found, with 2,583 genes differentially expressed in both species. Among these genes, key sex-determining factors previously reported in vertebrates and in bivalves (e.g., Sry, Dmrt1, Foxl2) were identified, suggesting that some steps of the sex-determination pathway may be deeply conserved in metazoans. Our results also support the hypothesis that a modified ubiquitination mechanism could be responsible for the retention of the paternal mtDNA in male bivalves, and revealed that DNA methylation could also be involved in the regulation of DUI. Globally, our results suggest that sets of genes associated with sex determination and DUI are similar in distantly-related DUI species

    Cochlear implantation in post-lingually deafened adults and elderly patients: analysis of audiometric and speech perception outcomes during the first year of use

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    Questo studio è volto alla valutazione degli outcomes audiometrici e logopedici dei pazienti anziani portatori di impianto cocleare durante il primo anno di utilizzo del dispositivo. Sono stati valutati 42 pazienti impiantati tra marzo 2010 e settembre 2014 presso lUO ORL dellAzienda Ospedaliera Universitaria di Padova. Sono stati inclusi nello studio pazienti affetti da sordità bilaterale postlinguale di grado severo-profondo impiantati unilateralmente. I soggetti sono stati divisi in tre gruppi in base allepoca della chirurgia: 14 soggetti con impianto fra i 35 e i 49 anni, 14 fra i 50 e i 64 anni e 14 impiantati a unetà superiore di 65 anni. Tutti i pazienti sono stati valutati prima e dopo la chirurgia (a 1, 3, 6 e 12 mesi di follow-up) attraverso lesecuzione di: audiometria tonale, audiometria vocale, test logopedici e somministrazione del questionario delle categorie percettive (CAP). Lanalisi statistica è stata effettuata attraverso il Students t-test. La totalità dei soggetti nei tre gruppi hanno dimostrato significativi miglioramenti allaudiometria tonale e vocale ai controlli post chirurgici rispetto alle performance ottenute precedentemente allimpianto. In particolare si sono verificati miglioramenti della soglia audiometrica media (PTA) senza differenze statisticamente significative tra i tre gruppi. risultati ottenuti nei test logopedici e dalla somministrazione del CAP hanno dimostrato evidenti miglioramenti in tutti i tre gruppi in studio. Abbiamo riscontrato, però, che i soggetti più giovani hanno raggiunto maggiori punteggi ai controlli post impianto rispetto a quelli più anziani. Concludendo, possiamo affermare che limpianto cocleare è un trattamento efficace per soggetti affetti da ipoacusia severa-profonda senza differenze significative nelle performance audiologiche e logopediche in relazione alletà di impianto. Anche se più lentamente, i pazienti impiantati dopo i 65 anni di età raggiungono performance ottimali e possono essere ritenuti dei candidati ottimali allintervento

    The standard error of measurement is a more appropriate measure of quality for postgraduate medical assessments than is reliability: an analysis of MRCP(UK) examinations

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    Background: Cronbach's alpha is widely used as the preferred index of reliability for medical postgraduate examinations. A value of 0.8-0.9 is seen by providers and regulators alike as an adequate demonstration of acceptable reliability for any assessment. Of the other statistical parameters, Standard Error of Measurement (SEM) is mainly seen as useful only in determining the accuracy of a pass mark. However the alpha coefficient depends both on SEM and on the ability range (standard deviation, SD) of candidates taking an exam. This study investigated the extent to which the necessarily narrower ability range in candidates taking the second of the three part MRCP(UK) diploma examinations, biases assessment of reliability and SEM.Methods: a) The interrelationships of standard deviation (SD), SEM and reliability were investigated in a Monte Carlo simulation of 10,000 candidates taking a postgraduate examination. b) Reliability and SEM were studied in the MRCP(UK) Part 1 and Part 2 Written Examinations from 2002 to 2008. c) Reliability and SEM were studied in eight Specialty Certificate Examinations introduced in 2008-9.Results: The Monte Carlo simulation showed, as expected, that restricting the range of an assessment only to those who had already passed it, dramatically reduced the reliability but did not affect the SEM of a simulated assessment. The analysis of the MRCP(UK) Part 1 and Part 2 written examinations showed that the MRCP(UK) Part 2 written examination had a lower reliability than the Part 1 examination, but, despite that lower reliability, the Part 2 examination also had a smaller SEM (indicating a more accurate assessment). The Specialty Certificate Examinations had small Ns, and as a result, wide variability in their reliabilities, but SEMs were comparable with MRCP(UK) Part 2.Conclusions: An emphasis upon assessing the quality of assessments primarily in terms of reliability alone can produce a paradoxical and distorted picture, particularly in the situation where a narrower range of candidate ability is an inevitable consequence of being able to take a second part examination only after passing the first part examination. Reliability also shows problems when numbers of candidates in examinations are low and sampling error affects the range of candidate ability. SEM is not subject to such problems; it is therefore a better measure of the quality of an assessment and is recommended for routine use
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