702 research outputs found

    Energy and Charged Particle Flow in 10.8 A GeV/c Au+Au Collisions

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    Experimental results and a detailed analysis are presented of the transverse energy and charged particle azimuthal distributions measured by the E877 collaboration for different centralities of Au+Au collisions at a beam momentum of 10.8 A GeV/c. The anisotropy of these distributions is studied with respect to the reaction plane reconstructed on an event-by-event basis using the transverse energy distribution measured by calorimeters. Results are corrected for the reaction plane resolution. For semicentral events we observe directed flow signals of up to ten percent. We observe a stronger anisotropy for slow charged particles. For both the charged particle and transverse energy distributions we observe a small but non zero elliptic anisotropy with the major axis pointing into the reaction plane. Combining the information on transverse energy and charged particle flow we obtain information on the flow of nucleons and pions. The data are compared to event generators and the need to introduce a mean field or nucleon-nucleon potential is discussed.Comment: RevTex, 25 pages, 13 figures included as one Postscript file, submitted to Phys. Rev.

    Multisystem proteinopathy due to a homozygous p.Arg159His VCP mutation : a tale of the unexpected

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    ObjectiveTo assess the clinical, radiologic, myopathologic, and proteomic findings in a patient manifesting a multisystem proteinopathy due to a homozygous valosin-containing protein gene (VCP) mutation previously reported to be pathogenic in the heterozygous state.MethodsWe studied a 36-year-old male index patient and his father, both presenting with progressive limb-girdle weakness. Muscle involvement was assessed by MRI and muscle biopsies. We performed whole-exome sequencing and Sanger sequencing for segregation analysis of the identified p.Arg159His VCP mutation. To dissect biological disease signatures, we applied state-of-the-art quantitative proteomics on muscle tissue of the index case, his father, 3 additional patients with VCP-related myopathy, and 3 control individuals.ResultsThe index patient, homozygous for the known p.Arg159His mutation in VCP, manifested a typical VCP-related myopathy phenotype, although with a markedly high creatine kinase value and a relatively early disease onset, and Paget disease of bone. The father exhibited a myopathy phenotype and discrete parkinsonism, and multiple deceased family members on the maternal side of the pedigree displayed a dementia, parkinsonism, or myopathy phenotype. Bioinformatic analysis of quantitative proteomic data revealed the degenerative nature of the disease, with evidence suggesting selective failure of muscle regeneration and stress granule dyshomeostasis.ConclusionWe report a patient showing a multisystem proteinopathy due to a homozygous VCP mutation. The patient manifests a severe phenotype, yet fundamental disease characteristics are preserved. Proteomic findings provide further insights into VCP-related pathomechanisms

    Enhancement of cargo processivity by cooperating molecular motors

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    Cellular cargo can be bound to cytoskeletal filaments by one or multiple active or passive molecular motors. Recent experiments have shown that the presence of auxiliary, nondriving motors, results in an enhanced processivity of the cargo, compared to the case of a single active motor alone. We model the observed cooperative transport process using a stochastic model that describes the dynamics of two molecular motors, an active one that moves cargo unidirectionally along a filament track and a passive one that acts as a tether. Analytical expressions obtained from our analysis are fit to experimental data to estimate the microscopic kinetic parameters of our model. Our analysis reveals two qualitatively distinct processivity-enhancing mechanisms: the passive tether can decrease the typical detachment rate of the active motor from the filament track or it can increase the corresponding reattachment rate. Our estimates unambiguously show that in the case of microtubular transport, a higher average run length arises mainly from the ability of the passive motor to keep the cargo close to the filament, enhancing the reattachment rate of an active kinesin motor that has recently detached. Instead, for myosin-driven transport along actin, the passive motor tightly tethers the cargo to the filament, suppressing the detachment rate of the active myosin.Comment: 11 pages, 8 figures, submitted to PCC

    Evaluating the efficiency of membrane's refurbishment solutions to perform vertical extensions in old buildings using a multicriteria decision-support model

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    The initial premise of this research is that the relative efficiency of refurbishment solutions with architectural membranes needs to be measured in order to allow its comparison with conventional solutions, helping decision makers to select the most efficient solutions. The evaluation of this efficiency depends on economic features, but also on functional, technological and environmental ones. This study presents a model to solve this problem, using decision trees, multicriteria decision-making methods (SAW and AHP) and a sensitivity analysis. The selection of the criteria and the assignment of the corresponding weights was attained through an expert group survey for a baseline scenario, aiming maximizing functional performance (such as energy savings) and minimizing employed resources (materials, costs, etc.). The most efficient refurbishment solution among the set of alternatives was reached using the developed model. The methodology was applied to a case study - an old building from the nineteenth century, located in Portugal, which was refurbished with a vertical extension. The result reveals that the proposed model is successful and illustrates the potential of this evaluation methodology to compare and quantify the efficiency of a series of different lightweight constructive solutions. It also underlines the advantages of using lightweight building technologies, especially with architectural membrane materials, in building refurbishments.This research was made possible by the support of the: Portuguese Foundation for Science and Technology (FCT), Portuguese Ministry of Education and Science (MCE) and European Social Fund (ESF) with the reference grant SFRH/BD/104891/2014; the Project UID/AUR/04509/2013 by FCTMEC by national funding and FEDER co-financing under the new PT2020 partnership agreement - Lab2PT, School of Architecture/University of Minho, Portugal; and Project POCI-01-0145-FEDER-007457 - CONSTRUCT - Institute of R&D In Structures and Construction of Faculty of Engineering/University of Porto, Portugal, funded by FEDER funds through COMPETE2020

    Evaluation of elicitation methods to quantify Bayes linear models

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    The Bayes linear methodology allows decision makers to express their subjective beliefs and adjust these beliefs as observations are made. It is similar in spirit to probabilistic Bayesian approaches, but differs as it uses expectation as its primitive. While substantial work has been carried out in Bayes linear analysis, both in terms of theory development and application, there is little published material on the elicitation of structured expert judgement to quantify models. This paper investigates different methods that could be used by analysts when creating an elicitation process. The theoretical underpinnings of the elicitation methods developed are explored and an evaluation of their use is presented. This work was motivated by, and is a precursor to, an industrial application of Bayes linear modelling of the reliability of defence systems. An illustrative example demonstrates how the methods can be used in practice

    Nuclear localization of Annexin A7 during murine brain development

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    BACKGROUND: Annexin A7 is a member of the annexin protein family, which is characterized by its ability to interact with phospholipids in the presence of Ca(2+)-ions and which is thought to function in Ca(2+)-homeostasis. Results from mutant mice showed altered Ca(2+)-wave propagation in astrocytes. As the appearance and distribution of Annexin A7 during brain development has not been investigated so far, we focused on the distribution of Annexin A7 protein during mouse embryogenesis in the developing central nervous system and in the adult mouse brain. RESULTS: Annexin A7 is expressed in cells of the developing brain where a change in its subcellular localization from cytoplasm to nucleus was observed. In the adult CNS, the subcellular distribution of Annexin A7 depends on the cell type. By immunohistochemistry analysis Annexin A7 was detected in the cytosol of undifferentiated cells at embryonic days E5–E8. At E11–E15 the protein is still present in the cytosol of cells predominantly located in the ventricular germinative zone surrounding the lateral ventricle. Later on, at embryonic day E16, Annexin A7 in cells of the intermediate and marginal zone of the neopallium translocates to the nucleus. Neuronal cells of all areas in the adult brain present Annexin A7 in the nucleus, whereas glial fibrillary acidic protein (GFAP)-positive astrocytes exhibit both, a cytoplasmic and nuclear staining. The presence of nuclear Annexin A7 was confirmed by extraction of the nucleoplasm from isolated nuclei obtained from neuronal and astroglial cell lines. CONCLUSION: We have demonstrated a translocation of Annexin A7 to nuclei of cells in early murine brain development and the presence of Annexin A7 in nuclei of neuronal cells in the adult animal. The role of Annexin A7 in nuclei of differentiating and mature neuronal cells remains elusive

    Active Tension Network model suggests an exotic mechanical state realized in epithelial tissues.

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    Mechanical interactions play a crucial role in epithelial morphogenesis, yet understanding the complex mechanisms through which stress and deformation affect cell behavior remains an open problem. Here we formulate and analyze the Active Tension Network (ATN) model, which assumes that the mechanical balance of cells within a tissue is dominated by cortical tension and introduces tension-dependent active remodeling of the cortex. We find that ATNs exhibit unusual mechanical properties. Specifically, an ATN behaves as a fluid at short times, but at long times supports external tension like a solid. Furthermore, an ATN has an extensively degenerate equilibrium mechanical state associated with a discrete conformal - "isogonal" - deformation of cells. The ATN model predicts a constraint on equilibrium cell geometries, which we demonstrate to approximately hold in certain epithelial tissues. We further show that isogonal modes are observed in the fruit y embryo, accounting for the striking variability of apical areas of ventral cells and helping understand the early phase of gastrulation. Living matter realizes new and exotic mechanical states, the study of which helps to understand biological phenomena

    Engagement 2.0. Vom passiven Wahrnehmen zum aktiven Nutzen neuer Kommunikationstechnologien

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    Im vorliegenden Beitrag beschreiben die Autoren einen seit zwei Jahren am Bundesinstitut fĂŒr Erwachsenenbildung situierten Kurs, der engagierte Menschen in die Kommunikationstechniken und -werkzeuge im sogenannten Web 2.0 einfĂŒhrt. Als "politische Kommunikation" betrachten sie alle öffentlichkeitswirksamen bzw. zielgruppenbezogenen AktivitĂ€ten fĂŒr Anliegen, die im Selbstbewusstsein der AkteurInnen als öffentlich, als Interessen der Allgemeinheit oder aber auch als moralische AnsprĂŒche an die Gesellschaft verstanden werden. Den Abschluss des Beitrages bildet der Ausblick auf eine im Entstehen befindliche Webcommunity der AbsolventInnen des Kurses. (DIPF/Orig.)The authors of the present article describe a course at the Austrian Federal Institute of Adult Education (bifeb) that has introduced dedicated people to Web 2.0 communication technologies and tools for the last two years. For the authors, “political communication” represents all public-oriented and target group related activities surrounding matters that are considered to be public in the self-awareness of those involved, interests of the general public or also moral demands on society. The end of the article provides a panorama of the web community that is being created by the course graduates. (DIPF/Orig.

    Proton and Pion Production in Au+Au Collisions at 10.8A GeV/c

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    We present proton and pion tranverse momentum spectra and rapidity distributions for Au+Au collisions at 10.8A GeV/c. The proton spectra exhibit collective transverse flow effects. Evidence of the influence of the Coulomb interaction from the fireball is found in the pion transverse momentum spectra. The data are compared with the predictions of the RQMD event generator.Comment: plain tex (revtex), 24 pages Submitted to Phys. Rev.
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