Enabling dCache to use preexistent mass storage systems

A mesura que la investigació depèn cada vegada més dels computadors, l'emmagatzematge de dades comença a convertir-se en un recurs escàs per als projectes, i suposa una gran part del cost total. Alguns projectes intenten resoldre aquest problema emprant emmagatzament distribuït. És doncs necessari que alguns centres proveeixin de grans quantitats d'emmagatzematge massiu de baix cost basat en cintes magnètiques. L'inconvenient d'aquesta solució és que el rendiment disminueix, particularment a l'hora de tractar-se de grans quantitats d'arxius petits. El nostre objectiu és crear un híbrid entre un sistema d'alt cost i rendiment basat en discs, i un de baix cost i rendiment basat en cintes. Per això, unirem dCache, un sistema d'emmagatzematge distribuït, amb Castor, un sistema d'emmagatzematge jeràrquic, creant sistemes de fitxers virtuals que contindran grans quantitats d'arxius petits per millorar el rendiment global del sistema.

Evaluation of susceptibility of pear and plum varieties and rootstocks to Ca. P. pyri and Ca. P. prunorum using Real-Time PCR

Real-time PCR was used to quantify phytoplasma concentration in fifty inoculated trees from five Prunus rootstocks and in forty-eight symptomatic pear and Japanese plum trees from orchards. Seasonal fluctuation of Ca. P. prunorum in different Prunus rootstocks, over three years, showed that the highest percentage detected by nested-PCR was in the ‘Garnem’ rootstock on nearly all sampling dates. Intra-varietal differences were also observed. Phytoplasma titer could be estimated by real time PCR in some trees of the rootstocks ‘Garnem’, ‘Barrier’, ‘GF-677’ and ‘Marianna’, and ranged from 4.7x105 to 3.18x109 phytoplasmas per gram of tissue. Quantification by real-time PCR was not possible in the ‘Cadaman’ trees analyzed, probably due to a lower phytoplasma titer in this variety. Samples from infected trees from commercial plots had different phytoplasma concentration and detection percentage depending on the variety, both being lower in ‘Fortune’ and ‘606’ Japanese plum and in ‘Blanquilla’ pear trees.

Disseny i implementació d’una “Storage Area Network”

El següent projecte consisteix en analitzar com funciona un sistema SAN, per tal de veure comes pot obtenir un millor rendiment. L’objectiu principal es saber com es comportarà la nostra SAN muntada amb iSCSI a través de la xarxa, volem veure quines són les operacions, les dades i els resultats que comporta crear una RAID a través de discos no locals d’un ordinador i a través d’una xarxa LAN

Intraovarian sperm storage in Helicolenus dactylopterus dactylopterus fertilitzation, crypt formation and maintenance of stored sperm

The females of the bluemouth rockfish, Helicolenus dactylopterus dactylopterus (DelaRoche, 1809), store sperm within their ovaries for periods of up to 10 months. Twenty six females with standard lengths between 152 and 257 mm and six males with standard lengths between 253 and 209 mm were caught storage crypts with stored spermatozoa and to describe their evolution over the year. After internal fertilization and once sperm reaches the ovary, a crypt forms probably by an epithelial inclusion at the base of the lamellae of one or several spermatozoa groups that are floating freely in the interlamellar space of the ovarian lumen. Stored spermatozoa have a large cytoplasm bag surrounding their heads. This bag could serve as a nutritive reservoir during the long storage period. Many desmosonal and tight junctions between the crypt cells ensure tha male sex cells are protected against the female immune system

Reliable and persistent storage for CoDeS a distributed collaborative system

This research is aimed to find a solution for a distributed storage system adapted for CoDeS. By studying how DSSs work and how they are implemented, we can conclude how we can implement a DSS compatible with CoDeS requirements.

Spermiogenesis particularities of a sperm storage species: Helicolenus dactylopterus (Teleostei: Scorpaenidae)

A study of the spermiogenesis and spermatozoa of Helicolenus dactylopterus was conducted. Females of this species have the capacity to store sperm within their ovaries, and male gametes have a considerable cytoplasmic mass surrounding their heads to survive the long period of intraovarian sperm storage. Our observations show that early spermatids are round-shaped cells and have a spherical nucleus with diffuse chromatin. The nuclear volume decreases as a result of progressive chromatin condensation during spermiogenesis, causing the nucleus to take on a U-shape. Flagellar insertion is not central to the nucleus but consistently occurs at an oblique angle towards one side of it. The flagellum is inserted into the nuclear fossa, without subsequent nuclear rotation. In mature spermatozoa, the flagellum is adjacent to the nucleus. A comparison of the spermatozoa in the testicular lobules and those in the intraovarian storage structures suggests that the increase in volume of the cytoplasmic mass may occur in the posterior region of the testis, in the testicular duct. Spermatozoa enter the ovary in groups that reach the ovarian lumen and are surrounded by the ovarian epithelium for storage in sperm storage crypts

Recent human evolution has shaped geographical differences in susceptibility to disease

Background: Searching for associations between genetic variants and complex diseases has been a very active area of research for over two decades. More than 51,000 potential associations have been studied and published, a figure that keeps increasing, especially with the recent explosion of array-based Genome-Wide Association Studies. Even if the number of true associations described so far is high, many of the putative risk variants detected so far have failed to be consistently replicated and are widely considered false positives. Here, we focus on the world-wide patterns of replicability of published association studies.Results: We report three main findings. First, contrary to previous results, genes associated to complex diseases present lower degrees of genetic differentiation among human populations than average genome-wide levels. Second, also contrary to previous results, the differences in replicability of disease associated-loci between Europeans and East Asians are highly correlated with genetic differentiation between these populations. Finally, highly replicated genes present increased levels of high-frequency derived alleles in European and Asian populations when compared to African populations. Conclusions: Our findings highlight the heterogeneous nature of the genetic etiology of complex disease, confirm the importance of the recent evolutionary history of our species in current patterns of disease susceptibility and could cast doubts on the status as false positives of some associations that have failed to replicate across populations.

Impaired fast-spiking, suppressed cortical inhibition and increased susceptibility to seizures in mice lacking Kv3.2 K+ channel proteins

Voltage-gated K+ channels of the Kv3 subfamily have unusual electrophysiological properties, including activation at very depolarized voltages (positive to −10 mV) and very fast deactivation rates, suggesting special roles in neuronal excitability. In the brain, Kv3 channels are prominently expressed in select neuronal populations, which include fast-spiking (FS) GABAergic interneurons of the neocortex, hippocampus, and caudate, as well as other high-frequency firing neurons. Although evidence points to a key role in high-frequency firing, a definitive understanding of the function of these channels has been hampered by a lack of selective pharmacological tools. We therefore generated mouse lines in which one of the Kv3 genes, Kv3.2, was disrupted by gene-targeting methods. Whole-cell electrophysiological recording showed that the ability to fire spikes at high frequencies was impaired in immunocytochemically identified FS interneurons of deep cortical layers (5-6) in which Kv3.2 proteins are normally prominent. No such impairment was found for FS neurons of superficial layers (2-4) in which Kv3.2 proteins are normally only weakly expressed. These data directly support the hypothesis that Kv3 channels are necessary for high-frequency firing. Moreover, we found that Kv3.2 −/− mice showed specific alterations in their cortical EEG patterns and an increased susceptibility to epileptic seizures consistent with an impairment of cortical inhibitory mechanisms. This implies that, rather than producing hyperexcitability of the inhibitory interneurons, Kv3.2 channel elimination suppresses their activity. These data suggest that normal cortical operations depend on the ability of inhibitory interneurons to generate high-frequency firing.

A variant in the gene FUT9 is associated with susceptibility to placental malaria infection

Malaria in pregnancy forms a substantial part of the worldwide burden of malaria, with an estimated annual death toll of up to 200,000 infants, as well as increased maternal morbidity and mortality. Studies of genetic susceptibility to malaria have so far focused on infant malaria, with only a few studies investigating the genetic basis of placental malaria, focusing only on a limited number of candidate genes. The aim of this study therefore was to identify novel host genetic factors involved in placental malaria infection. To this end we carried out a nested case-control study on 180 Mozambican pregnant women with placental malaria infection, and 180 controls within an intervention trial of malaria prevention. We genotyped 880 SNPs in a set of 64 functionally related genes involved in glycosylation and innate immunity. A SNP located in the gene FUT9, rs3811070, was significantly associated with placental malaria infection (OR = 2.31, permutation p-value = 0.028). Haplotypic analysis revealed a similarly strong association of a common haplotype of four SNPs including rs3811070. FUT9 codes for a fucosyl-transferase that is catalyzing the last step in the biosynthesis of the Lewis-x antigen, which forms part of the Lewis blood group-related antigens. These results therefore suggest an involvement of this antigen in the pathogenesis of placental malaria infection.

Allele variants in functional MicroRNA target sites of the neurotrophin-3 receptor gene (NTRK3) as susceptibility factors for anxiety disorders

Genetic and functional data indicate that variation in the expression of the neurotrophin-3 receptor gene (NTRK3) may have an impact on neuronal plasticity, suggesting a role for NTRK3 in the pathophysiology of anxiety disorders. MicroRNA (miRNA) posttranscriptional gene regulators act by base-pairing to specific sequence sites, usually at the 3'UTR of the target mRNA. Variants at these sites might result in gene expression changes contributing to disease susceptibility. We investigated genetic variation in two different isoforms of NTRK3 as candidate susceptibility factors for anxiety by resequencing their 3'UTRs in patients with panic disorder (PD), obsessive-compulsive disorder (OCD), and in controls. We have found the C allele of rs28521337, located in a functional target site for miR-485-3p in the truncated isoform of NTRK3, to be significantly associated with the hoarding phenotype of OCD. We have also identified two new rare variants in the 3'UTR of NTRK3, ss102661458 and ss102661460, each present only in one chromosome of a patient with PD. The ss102661458 variant is located in a functional target site for miR-765, and the ss102661460 in functional target sites for two miRNAs, miR-509 and miR-128, the latter being a brain-enriched miRNA involved in neuronal differentiation and synaptic processing. Interestingly, these two variants significantly alter the miRNA-mediated regulation of NTRK3, resulting in recovery of gene expression. These data implicate miRNAs as key posttranscriptional regulators of NTRK3 and provide a framework for allele-specific miRNA regulation of NTRK3 in anxiety disorders.

Genetic and genomic analysis modeling of germline c-MYC overexpression and cancer susceptibility

Background: Germline genetic variation is associated with the differential expression of many human genes. The phenotypic effects of this type of variation may be important when considering susceptibility to common genetic diseases. Three regions at 8q24 have recently been identified to independently confer risk of prostate cancer. Variation at 8q24 has also recently been associated with risk of breast and colorectal cancer. However, none of the risk variants map at or relatively close to known genes, with c-MYC mapping a few hundred kilobases distally. Results: This study identifies cis-regulators of germline c-MYC expression in immortalized lymphocytes of HapMap individuals. Quantitative analysis of c-MYC expression in normal prostate tissues suggests an association between overexpression and variants in Region 1 of prostate cancer risk. Somatic c-MYC overexpression correlates with prostate cancer progression and more aggressive tumor forms, which was also a pathological variable associated with Region 1. Expression profiling analysis and modeling of transcriptional regulatory networks predicts a functional association between MYC and the prostate tumor suppressor KLF6. Analysis of MYC/Myc-driven cell transformation and tumorigenesis substantiates a model in which MYC overexpression promotes transformation by down-regulating KLF6. In this model, a feedback loop through E-cadherin down-regulation causes further transactivation of c-MYC.Conclusion: This study proposes that variation at putative 8q24 cis-regulator(s) of transcription can significantly alter germline c-MYC expression levels and, thus, contribute to prostate cancer susceptibility by down-regulating the prostate tumor suppressor KLF6 gene.

On moments and tail behaviors of storage processes

We study the existence of moments and the tail behaviour of the densitiesof storage processes. We give sufficient conditions for existence andnon-existence of moments using the integrability conditions ofsubmultiplicative functions with respect to Lévy measures. Then, we studythe asymptotical behavior of the tails of these processes using the concaveor convex envelope of the release rate function.

Towards storage and access of electronic theses: A proposal of its organisation for the Consortium of Catalan Libraries

Els objectius d'aquest informe són realitzar un estudi de la tècnica en la digitalització, l'emmagatzematge i l'accés a les tesis doctorals electròniques, per tal de fer una proposta d’organització al Consorci de Biblioteques Universitàries de Catalunya (CBUC). Actualment, tot i que existeixen diverses iniciatives a Europa, és als EUA on la digitalització de tesis doctorals s’ha desenvolupat més amb la creació de la Networked Digital Library for Theses and Dissertation (NDLTD), i ha estat qui ha definit els estàndards en aquest camp. En el següent informe es planteja i es recomana al CBUC l’adhesió institucional a l’NDLTD per poder gaudir de la seva experiència.

Conduction mechanisms and charge storage in Si-nanocrystals metal-oxide-semiconductor memory devices studied with conducting atomic force microscopy

In this work, we demonstrate that conductive atomic force microscopy (C-AFM) is a very powerful tool to investigate, at the nanoscale, metal-oxide-semiconductor structures with silicon nanocrystals (Si-nc) embedded in the gate oxide as memory devices. The high lateral resolution of this technique allows us to study extremely small areas ( ~ 300nm2) and, therefore, the electrical properties of a reduced number of Si-nc. C-AFM experiments have demonstrated that Si-nc enhance the gate oxide electrical conduction due to trap-assisted tunneling. On the other hand, Si-nc can act as trapping centers. The amount of charge stored in Si-nc has been estimated through the change induced in the barrier height measured from the I-V characteristics. The results show that only ~ 20% of the Si-nc are charged, demonstrating that the electrical behavior at the nanoscale is consistent with the macroscopic characterization.

Spin polarized neutron matter and magnetic susceptibility within the Brueckner-Hartree-Fock approximation

The Brueckner-Hartree-Fock formalism is applied to study spin polarized neutron matter properties. Results of the total energy per particle as a function of the spin polarization and density are presented for two modern realistic nucleon-nucleon interactions, Nijmegen II and Reid93. We find that the dependence of the energy on the spin polarization is practically parabolic in the full range of polarizations. The magnetic susceptibility of the system is computed. Our results show no indication of a ferromagnetic transition which becomes even more difficult as the density increases.