1,328 research outputs found

    Puente sobre el tramo inferior del Elba, Hamburgo

    Get PDF
    This bridge joins to Hamburg-Hannover and the Hamburg-Lübeck roadways. It is 411 m long, 30.74 m wide, and has five spans. The main span is 172 m long, and is suspended by cables from two towers, rising 53 m above the bridge pavement. The stiffening; structure of this suspended span consists of a central box and two lateral full web girders, with a uniform depth of 2 ms. The towers support two sets of cables, which rest on supports situated at unequal heights with respect to each other. These supports are so arranged that thermal deformations shall not be excessive nor cause large secondary moments. Most of the bridge elements have been manufactured in the workshops and taken to the site by river transport. The main span has been built by successive overhangs, till the two sides have met together at the crown.Este puente, que une las autopistas Hamburgo-Hannover y Hamburgo-Lübeck, tiene 411 m de longitud, 30,74 m de anchura y 5 tramos. El entramado de rigidez del tramo central, de 173 m de luz, que está suspendido por cables que se apoyan en dos torres, de 53 m de altura respecto a la calzada, tiene la sección transversal formada por un cajón central y dos vigas laterales de alma llena con un canto uniforme de 3 m. Dichas torres soportan dos paquetes de cables que se apoyan en sillas montadas a diferente altura, estando estos apoyos organizados de forma que permitan los movimientos provocados por las diferencias de temperatura sin originar deformaciones abusivas ni momentos secundarios. La mayor parte de los elementos han sido prefabricados en taller y transportados por vía fluvial. La construcción del tramo central se ha realizado por voladizos sucesivos hasta llegar al cierre en la clave

    Nodal dynamics, not degree distributions, determine the structural controllability of complex networks

    Get PDF
    Structural controllability has been proposed as an analytical framework for making predictions regarding the control of complex networks across myriad disciplines in the physical and life sciences (Liu et al., Nature:473(7346):167-173, 2011). Although the integration of control theory and network analysis is important, we argue that the application of the structural controllability framework to most if not all real-world networks leads to the conclusion that a single control input, applied to the power dominating set (PDS), is all that is needed for structural controllability. This result is consistent with the well-known fact that controllability and its dual observability are generic properties of systems. We argue that more important than issues of structural controllability are the questions of whether a system is almost uncontrollable, whether it is almost unobservable, and whether it possesses almost pole-zero cancellations.Comment: 1 Figures, 6 page

    The genetic contribution of the NO system at the glutamatergic post-synapse to schizophrenia : further evidence and meta-analysis

    Get PDF
    NO is a pleiotropic signaling molecule and has an important role in cognition and emotion. In the brain, NO is produced by neuronal nitric oxide synthase (NOS-I, encoded by NOS1) coupled to the NMDA receptor via PDZ. interactions; this protein-protein interaction is disrupted upon binding of NOS1 adapter protein (encoded by NOS1AP) to NOS-I. As both NOS1 and NOS1AP were associated with schizophrenia, we here investigated these genes in greater detail by genotyping new samples and conducting a meta-analysis of our own and published data. In doing so, we confirmed association of both genes with schizophrenia and found evidence for their interaction in increasing risk towards disease. Our strongest finding was the NOS1 promoter SNP rs41279104, yielding an odds ratio of 1.29 in the meta-analysis. As findings from heterologous cell systems have suggested that the risk allele decreases gene expression, we studied the effect of the variant on NOS1 expression in human post-mortem brain samples and found that the risk allele significantly decreases expression of NOS1 in the prefrontal cortex. Bioinformatic analyses suggest that this might be due the replacement of six transcription factor binding sites by two new binding sites as a consequence of proxy SNPs. Taken together, our data argue that genetic variance in NOS1 resulting in lower prefrontal brain expression of this gene contributes to schizophrenia liability, and that NOS1 interacts with NOS1AP in doing so. The NOS1-NOS1AP PDZ interface may thus well constitute a novel target for small molecules in at least some forms of schizophrenia. PostprintPeer reviewe

    A Simple Method for Analyzing Exome Sequencing Data Shows Distinct Levels of Nonsynonymous Variation for Human Immune and Nervous System Genes

    Get PDF
    To measure the strength of natural selection that acts upon single nucleotide variants (SNVs) in a set of human genes, we calculate the ratio between nonsynonymous SNVs (nsSNVs) per nonsynonymous site and synonymous SNVs (sSNVs) per synonymous site. We transform this ratio with a respective factor f that corrects for the bias of synonymous sites towards transitions in the genetic code and different mutation rates for transitions and transversions. This method approximates the relative density of nsSNVs (rdnsv) in comparison with the neutral expectation as inferred from the density of sSNVs. Using SNVs from a diploid genome and 200 exomes, we apply our method to immune system genes (ISGs), nervous system genes (NSGs), randomly sampled genes (RSGs), and gene ontology annotated genes. The estimate of rdnsv in an individual exome is around 20% for NSGs and 30–40% for ISGs and RSGs. This smaller rdnsv of NSGs indicates overall stronger purifying selection. To quantify the relative shift of nsSNVs towards rare variants, we next fit a linear regression model to the estimates of rdnsv over different SNV allele frequency bins. The obtained regression models show a negative slope for NSGs, ISGs and RSGs, supporting an influence of purifying selection on the frequency spectrum of segregating nsSNVs. The y-intercept of the model predicts rdnsv for an allele frequency close to 0. This parameter can be interpreted as the proportion of nonsynonymous sites where mutations are tolerated to segregate with an allele frequency notably greater than 0 in the population, given the performed normalization of the observed nsSNV to sSNV ratio. A smaller y-intercept is displayed by NSGs, indicating more nonsynonymous sites under strong negative selection. This predicts more monogenically inherited or de-novo mutation diseases that affect the nervous system

    TLR9-Dependent and Independent Pathways Drive Activation of the Immune System by Propionibacterium Acnes

    Get PDF
    Propionibacterium acnes is usually a relatively harmless commensal. However, under certain, poorly understood conditions it is implicated in the etiology of specific inflammatory diseases. In mice, P. acnes exhibits strong immunomodulatory activity leading to splenomegaly, intrahepatic granuloma formation, hypersensitivity to TLR ligands and endogenous cytokines, and enhanced resistance to infection. All these activities reach a maximum one week after P. acnes priming and require IFN-γ and TLR9. We report here the existence of a markedly delayed (1–2 weeks), but phenotypically similar TLR9-independent immunomodulatory response to P. acnes. This alternative immunomodulation is also IFN-γ dependent and requires functional MyD88. From our experiments, a role for MyD88 in the IFN-γ-mediated P. acnes effects seems unlikely and the participation of the known MyD88-dependent receptors, including TLR5, Unc93B-dependent TLRs, IL-1R and IL-18R in the development of the alternative response has been excluded. However, the crucial role of MyD88 can partly be attributed to TLR2 and TLR4 involvement. Either of these two TLRs, activated by bacteria and/or endogenously generated ligands, can fulfill the required function. Our findings hint at an innate immune sensitizing mechanism, which is potentially operative in both infectious and sterile inflammatory disorders
    corecore