1,572 research outputs found

    Puente sobre el tramo inferior del Elba, Hamburgo

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    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

    Understanding students’ motivation towards proactive career behaviours through goal-setting theory and the job demands–resources model

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    The graduate labour market is highly competitive but little is known about why students vary in their development of employability. This study contributes to the literature by applying goal-setting theory and the job demands–resources model to investigate how motivational processes influence students’ proactive career behaviours. We tested four hypotheses using structural equation modelling and moderation/mediation analysis using a nested model approach; 432 undergraduates from 21 UK universities participated in this cross-sectional study. The results showed that students higher in mastery approach had greater perceived employability mediated by two proactive career behaviours (skill development and network building). Students’ career goal commitment was associated with all four proactive career behaviours (career planning, skill development, career consultation and network building). Students’ academic and employment workloads did not negatively impact their proactive career behaviours. University tutors and career services should therefore encourage students to set challenging career goals that reflect mastery approach

    Experimental Evidence of Direct Exchange Interaction Mediating Intramolecular Singlet Fission in Weakly-Coupled Dimers

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    The electronic interaction between an optically active singlet state (S1S0S_1S_0) and a dark state of singlet multiplicity, known as correlated triplet pair (1[TT]^1[TT]), plays a crucial role in the effective transformation from S1S0S_1S_0 to 1[TT]^1[TT] during intramolecular singlet fission (iSF). This process is understood through mechanisms such as direct exchange coupling and incoherent processes that involve super-exchange coupling through charge-transfer states. However, most insights into these mechanisms are derived from theoretical studies due to the difficulties in obtaining experimental evidence. In this study, we investigate the excited-state interactions between S1S0S_1S_0 and 1[TT]^1[TT] in spiro-conjugated iSF sensitizers by employing transient two-dimensional electronic spectroscopy. This approach allows us to focus on the early stages of the conversion from S1S0S_1S_0 to 1[TT]^1[TT]. Upon optical excitation, a superposition of S1S0S_1S_0 and 1[TT]^1[TT] is created, which gradually transitions to favor 1[TT]^1[TT] within the characteristic time frames of iSF. The observed high-order signals indicate circular repopulation dynamic that effectively reinitiates the iSF process from higher energy electronic states. Our findings, supported by semi-quantum-mechanical simulations of the experimental data, suggest the presence of a direct iSF mechanism in the dimers, facilitated by weak non-adiabatic coupling between S1S0S_1S_0 and 1[TT]^1[TT]. This experiment provides new insights into the equilibrium between the two electronic states, a phenomenon previously understood primarily through theoretical models.Comment: 26 pages, 4 Figure

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

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    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

    Epitaxial growth and anisotropy of La(O,F)FeAs thin films deposited by Pulsed Laser Deposition

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    LaFeAsO1-xFx thin films were deposited successfully on (001)-oriented LaAlO3 and MgO substrates from stoichiometric LaFeAsO1-xFx polycrystalline targets with fluorine concentrations up to x = 0.25 by PLD. Room temperature deposition and post annealing of the films yield nearly phase pure films with a pronounced c-axis texture and a strong biaxial in-plane orientation. Transport measurements show metallic resistance and onset of superconductivity at 11 K. Hc2(T) was determined by resistive measurements and yield Hc2 values of 3 T at 3.6 K for B||c and 6 T at 6.4 K for B||ab.Comment: 11 pages, 5 figure

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

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    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

    Albumin-coupled methotrexate (MTX-HSA) is a new anti-arthritic drug which acts synergistically to MTX

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    Objective. To evaluate the anti-arthritic effects of the new inflammation-targeted drug MTX-HSA and to investigate whether peripheral blood mononuclear cells (PBMC) are potential target cells for albumin-mediated drug delivery. Methods. The murine model of collagen-induced arthritis (CIA) was used to measure the anti-arthritic effect of MTX, MTX-HSA or a combination of both (n = 30 to 35 per group). In addition, the uptake of fluorescence-labelled albumin (AFLc-HSA) in PBMC of 14 patients with RA was measured by fluorescence-activated cell sorting (FACS). Results. In equivalent doses of 7.5 mg/kg intravenously (IV) twice a week, MTX-HSA is significantly (P<0.02) superior to MTX in inhibiting the development of CIA and reducing the joint count as well as the number of affected paws. When given in lower doses as combination therapy, both drugs act synergistically (P<0.03). A mean of 96, 72 and 64% of the CD14-, CD16- and CD20-positive cells from peripheral blood of rheumatoid arthritis (RA) patients showed an uptake of albumin after incubation with AFLc-HSA in vitro. This finding was not significantly different in comparison to healthy controls. In contrast, the number of CD3-positive cells taking up albumin is increased significantly in RA patients in comparison to controls (26.3 ± 12.9% s.d. vs 11.6 ± 7.3% s.d.; P = 0.005). Conclusion. The data show that the effectiveness of MTX-HSA in CIA is superior to MTX and that both drugs act synergistically. In addition, albumin appears to be taken up by peripheral blood cells, suggesting that they might be one of the potential target cells of this novel anti-arthritic treatment approac
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