600 research outputs found

    Estado del arte sobre la investigación en identidad organizacional

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    Working Paper del Departamento de Organización de Empreses de la Universitat Politècnica de Catalunya sobre la investigación en identidad organizacional.El estado del arte es una forma de aludir a lo que se sabe sobre una materia, lo que se ha dicho hasta el momento que ha sido más relevante. En este sentido la pretensión de este documento es situar al lector interesado en cuál es la situación de conocimiento actual sobre la identidad organizacional. Esta materia ha ido tomando relevancia en la investigación científica sobre dirección de empresas en los últimos años. De hecho, la identidad organizacional se ha revelado como un activo intangible de gran influencia en las organizaciones, hasta tal punto que su errónea evaluación o tratamiento puede conllevar graves repercusiones para la organización, incluso su desaparición. La identidad organizacional ha adquirido el interés científico, si bien los investigadores más relevantes en esta materia coinciden en que los trabajos de investigación no han alcanzado su culminación, más bien se encuentran en fases iniciales y animan a continuar investigando en este área de conocimiento.Preprin

    dReDBox: Materializing a full-stack rack-scale system prototype of a next-generation disaggregated datacenter

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    Current datacenters are based on server machines, whose mainboard and hardware components form the baseline, monolithic building block that the rest of the system software, middleware and application stack are built upon. This leads to the following limitations: (a) resource proportionality of a multi-tray system is bounded by the basic building block (mainboard), (b) resource allocation to processes or virtual machines (VMs) is bounded by the available resources within the boundary of the mainboard, leading to spare resource fragmentation and inefficiencies, and (c) upgrades must be applied to each and every server even when only a specific component needs to be upgraded. The dRedBox project (Disaggregated Recursive Datacentre-in-a-Box) addresses the above limitations, and proposes the next generation, low-power, across form-factor datacenters, departing from the paradigm of the mainboard-as-a-unit and enabling the creation of function-block-as-a-unit. Hardware-level disaggregation and software-defined wiring of resources is supported by a full-fledged Type-1 hypervisor that can execute commodity virtual machines, which communicate over a low-latency and high-throughput software-defined optical network. To evaluate its novel approach, dRedBox will demonstrate application execution in the domains of network functions virtualization, infrastructure analytics, and real-time video surveillance.This work has been supported in part by EU H2020 ICTproject dRedBox, contract #687632.Peer ReviewedPostprint (author's final draft

    Bases moleculars de la cistinúria

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    Els cDNA identificats actualment de transportadors d'aminoàcids en mamífers poden ser agrupats en quatre famílies. Una d'aquestes famílies la componen les proteïnes rBAT i la cadena pesada (hc) de l'antigen de superfície de membrana anomenat 4F2. Els RNA que codifiquen aquestes dues proteïnes indueixen activitat d'un sistema de transport d'aminoàcids tipus b (rBAT) i un altre de tipus y+L (4F2hc) en oocits de Xenopus laevis. Ambdós transportadors tenen un mecanisme de bescanvi obligatori d'aminoàcids que, en el cas de rBAT, pot acumular, per aquest mecanisme de transport actiu terciari , substrats a través de la membrana plasmàtica fins a 30-50 vegades en l'oòcit de Xenopus . Sorprenentment, tant rBAT com 4F2hc no són suficientment hidrofòbics i no semblen proteïnes formadores de porus en membranes. Això ha suggerit la hipòtesi que rBAT i 4F2hc són subunitats o moduladors dels corresponents transportadors. És significatiu que taut per a rBAT com per a 4F2hc s'ha suggerit o demostrat, respectivament , la seva associació amb subunitats lleugeres d'aproximadament 40 kD en una estructura de tipus heterodimèric

    Ribonucleotide reductases of Salmonella Typhimurium : transcriptional regulation and differential role in pathogenesis

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    Ribonucleotide reductases (RNRs) are essential enzymes that carry out the de novo synthesis of deoxyribonucleotides by reducing ribonucleotides. There are three different classes of RNRs (I, II and III), all having different oxygen dependency and biochemical characteristics. Salmonella enterica serovar Typhimurium (S. Typhimurium) harbors class Ia, class Ib and class III RNRs in its genome. We have studied the transcriptional regulation of these three RNR classes in S. Typhimurium as well as their differential function during infection of macrophage and epithelial cells. Deletion of both NrdR and Fur, two main transcriptional regulators, indicates that Fur specifically represses the class Ib enzyme and that NrdR acts as a global repressor of all three classes. A Fur recognition sequence within the nrdHIEF promoter has also been described and confirmed by electrophoretic mobility shift assays (EMSA). In order to elucidate the role of each RNR class during infection, S. Typhimurium single and double RNR mutants (as well as Fur and NrdR mutants) were used in infection assays with macrophage and epithelial cell lines. Our results indicate class Ia to be mainly responsible for deoxyribonucleotide production during invasion and proliferation inside macrophages and epithelial cells. Neither class Ib nor class III seem to be essential for growth under these conditions. However, class Ib is able to maintain certain growth in an nrdAB mutant during the first hours of macrophage infection. Our results suggest that, during the early stages of macrophage infection, class Ib may contribute to deoxyribonucleotide synthesis by means of both an NrdR and a Fur-dependent derepression of nrdHIEF due to hydrogen peroxide production and DNA damage associated with the oxidative burst, thus helping to overcome the host defenses

    CD98hc facilitates B cell proliferation and adaptive humoral immunity.

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    The proliferation of antigen-specific lymphocytes and resulting clonal expansion are essential for adaptive immunity. We report here that B cell-specific deletion of the heavy chain of CD98 (CD98hc) resulted in lower antibody responses due to total suppression of B cell proliferation and subsequent plasma cell formation. Deletion of CD98hc did not impair early B cell activation but did inhibit later activation of the mitogen-activated protein kinase Erk1/2 and downregulation of the cell cycle inhibitor p27. Reconstitution of CD98hc-deficient B cells with CD98hc mutants showed that the integrin-binding domain of CD98hc was required for B cell proliferation but that the amino acid-transport function of CD98hc was dispensable for this. Thus, CD98hc supports integrin-dependent rapid proliferation of B cells. We propose that the advantage of adaptive immunity favored the appearance of CD98hc in vertebrates

    Protein coding potential of retroviruses and other transposable elements in vertebrate genomes

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    We suggest an annotation strategy for genes encoded by retroviruses and transposable elements (RETRA genes) based on a set of marker protein domains. Usually RETRA genes are masked in vertebrate genomes prior to the application of automated gene prediction pipelines under the assumption that they provide no selective advantage to the host. Yet, we show that about 1000 genes in four vertebrate gene sets analyzed contain at least one RETRA gene marker domain. Using the conservation of genomic neighborhood (synteny), we were able to discriminate between RETRA genes with putative functionality in the vertebrates and those that probably function only in the context of mobile elements. We identified 35 such genes in human, along with their corresponding mouse and rat orthologs; which included almost all known human genes with similarity to mobile elements. The results also imply that the vast majority of the remaining RETRA genes in current gene sets are unlikely to encode vertebrate functions. To automatically annotate RETRA genes in other vertebrate genomes, we provide as a tool a set of marker protein domains and a manually refined list of domesticated or ancestral RETRA genes for rescuing genes with vertebrate functions

    Genome-wide association and HLA fine-mapping studies identify risk loci and genetic pathways underlying allergic rhinitis

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    Allergic rhinitis is the most common clinical presentation of allergy, affecting 400 million people worldwide, with increasing incidence in westernized countries1,2. To elucidate the genetic architecture and understand the underlying disease mechanisms, we carried out a meta-analysis of allergic rhinitis in 59,762 cases and 152,358 controls of European ancestry and identified a total of 41 risk loci for allergic rhinitis, including 20 loci not previously associated with allergic rhinitis, which were confirmed in a replication phase of 60,720 cases and 618,527 controls. Functional annotation implicated genes involved in various immune pathways, and fine mapping of the HLA region suggested amino acid variants important for antigen binding. We further performed genome-wide association study (GWAS) analyses of allergic sensitization against inhalant allergens and nonallergic rhinitis, which suggested shared genetic mechanisms across rhinitis-related traits. Future studies of the identified loci and genes might identify novel targets for treatment and prevention of allergic rhinitis
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