Analytical Formulation of the Jacobian Matrix for Non-linear Calculation of the Forced Response of Turbine Blade Assemblies with Wedge Friction Dampers

A fundamental issue in turbomachinery design is the dynamical stress assessment of turbine blades. In order to reduce stress peaks in the turbine blades at engine orders corresponding to blade natural frequencies, friction dampers are employed. Blade response calculation requires the solution of a set of non-linear equations originated by the introduction of friction damping. Such a set of non-linear equations is solved using the iterative numerical Newton-Raphson method. However, calculation of the Jacobian matrix of the system using classical numerical finite difference schemes makes frequency domain solver prohibitively expensive for structures with many contact points. Large computation time results from the evaluation of partial derivatives of the non-linear equations with respect to the displacements. In this work a methodology to compute efficiently the Jacobian matrix of a dynamic system having wedge dampers is presented. It is exact and completely analytical. The proposed methods have been successfully applied to a real intermediate pressure turbine (IPT) blade under cyclic symmetry boundary conditions with underplatform wedge dampers. Its implementation showed to be very effective, and allowed to achieve relevant time savings without loss of precision

Hippocampal Regulation of Postsynaptic Density Homer1 by Associative Learning

Genes involved in synaptic plasticity, particularly genes encoding postsynaptic density proteins, have been recurrently linked to psychiatric disorders including schizophrenia and autism. Postsynaptic density Homer1 proteins contribute to synaptic plasticity through the competing actions of short and long isoforms. The activity-induced expression of shortHomer1isoforms,Homer1aandAnia-3, is thought to be related to processes of learning and memory. However, the precise regulation ofHomer1aandAnia-3with different components of learning has not been investigated. Here, we used in situ hybridization to quantify short and longHomer1expression in the hippocampus following consolidation, retrieval, and extinction of associative fear memory, using contextual fear conditioning in rats.Homer1aandAnia-3, but not longHomer1, were regulated by contextual fear learning or novelty detection, although their precise patterns of expression in hippocampal subregions were dependent on the isoform. We also show for the first time that the two short Homer1 isoforms are regulated after the retrieval and extinction of contextual fear memory, albeit with distinct temporal and spatial profiles. These findings support a role of activity-induced Homer1 isoforms in learning and memory processes in discrete hippocampal subregions and suggest that Homer1a and Ania-3 may play separable roles in synaptic plasticity.</jats:p

Should I stay or should I go? Exit options within mixed systems of public and private health care finance

Mixed public–private finance is widespread in health care systems internationally. In one variant of mixed finance, some countries (e.g., Germany) allow eligible beneficiaries to fully exit from the public (social insurance) system and purchase private insurance. Using a controlled laboratory experiment, we empirically investigate the predictions of a political economy model of mixed systems of public and private finance with two types of exit: universal-exit, when all individuals can choose to exit the public system, and conditional-exit, when only individuals with an income at or above a threshold income level can choose to exit. We find that high-income individuals are less likely to exit under universal-exit than under conditional-exit, despite having the same incentive to exit in both treatments. Sensitivity treatments suggests that a number of factors may be at play in explaining this result, including learning effects, a priming effect and a framing effect, but that other-regarding preferences do not appear to be an important factor

Support for public provision of a private good with top-up and opt-out: A controlled laboratory experiment

This paper presents the results of a revealed-choice experiment testing the theoretical predictions of political economy models regarding public support for a publicly provided private good financed with proportional income taxes when individuals can purchase the good privately and either continue to consume public provision (‘top-up’) or forego public provision (‘opt-out’), but in each case continue to pay income taxes. Our laboratory results confirm behavior is consistent with the predicted majority-preferred tax rate under mixed financing with top-up, but we identify preferences for significantly higher rates of public provision than predicted under mixed financing with opt-out. Using non parametric regression analysis, we explore the relationship between individuals’ top-up and opt-out decisions and both their income levels and the implemented tax rates

A Behavioral Economic Study of Tax Rate Selection by the Median Voter: Can the Tax Rate Be Influenced by the Name of the Publicly Provided Private Good?

This paper presents the results of a behavioral economics study to test if the tax rates submitted to finance the public provision of a private good are influenced by changing the name of the private good. A revealed-preference laboratory decision-making experiment is used to test if participants choose significantly different tax rates to support provision of a private good named as a health care investment compared to an identical good named as a neutral monetary investment. Although some previous studies focusing on both framing and context effects find differences associated with health versus non-health environments, these studies have not involved voting over public provision of a private good. In our experimental environment, participants with different income endowments provide their preferred proportional tax rates for financing public provision of a private good in either a neutral or a health context. The implemented tax rate is the median preferred tax rate, and once the budget is determined, each participant receives the same quantity of the publicly provided private good. In each context, the payoff functions are the same. The only difference between the contexts is the name attached to the publicly provided private good, regardless of the name attached to the publicly provided private good, consuming it imposes no externalities. This controls for the positive externality characteristics of many health care goods, but not for preferences evoked by the merit good character of health care which factor into decisions about the public provision of health care. We find that the theoretical predictions of the median voter model are generally supported by the data. However, the conjecture that the implemented tax rate would be affected by context is not supported by the results

Chromosome instability and benefit from adjuvant anthracyclines in breast cancer

BACKGROUND: Duplication of the centromeric region of chromosome 17 (Ch17CEP) is associated with sensitivity to anthracyclines. An explanation may be chromosome instability (CIN); a frequent event in solid tumours associated with poor outcome. The predictive value of CIN seems to be drug dependent and CIN has been associated with both sensitivity and resistance to chemotherapy. METHODS: In this study, we used fluorescent in situ hybridisation for chromosomes 1, 7, 11, 17 and 18 to identify patients with high tumour CIN% in 322 patients recruited into the BR9601 clinical trial. RESULTS: High tumour CIN% was correlated to Ch17CEP (P=3.68e−7) and is associated with a reduced RFS (P=0.0011) and OS (P=0.04). Patients with high CIN had a decreased risk of death on E-CMF compared with CMF. CONCLUSION: CIN is of prognostic significance and may be of predictive value in determining anthracycline response, although further testing is required

Deeper, Wider, Sharper: Next-Generation Ground-Based Gravitational-Wave Observations of Binary Black Holes

Next-generation observations will revolutionize our understanding of binary black holes and will detect new sources, such as intermediate-mass black holes. Primary science goals include: Discover binary black holes throughout the observable Universe; Reveal the fundamental properties of black holes; Uncover the seeds of supermassive black holes.Comment: 14 pages, 3 figures, White Paper Submitted to Astro2020 (2020 Astronomy and Astrophysics Decadal Survey) by GWIC 3G Science Case Team (GWIC: Gravitational Wave International Committee

Peripheral blood responses to specific antigens and CD28 in sarcoidosis

SummaryBackgroundPotential antigens inducing sarcoid inflammation include mycobacterial and auto-antigens. Paradoxically, peripheral anergy to common recall antigens also occurs, possibly due to impaired dendritic cell or regulatory T-cell responses, or impaired T-cell co-stimulation. The purpose of this study was to compare peripheral blood responses of patients with sarcoidosis to candidate antigens, and examine CD28 T-cell co-stimulation.MethodsPeripheral blood mononuclear cell (PBMC) responses were examined from patients with sarcoidosis (n=16) and healthy control subjects (n=22) following PBMC stimulation with: anti-CD3/CD28 coated beads; Mycobacterium tuberculosis ESAT-6 and KatG peptides; vimentin and lysyl tRNA peptides; and common recall antigens, including cytomegalovirus (CMV) cell lysate as well as CMV, Epstein-Barr virus, influenza virus (CEF) peptides.ResultsESAT-6/KatG peptide stimulation induced greater numbers of IFN-γ producing T-cells, and elevated IL-2, IL-6 and TNF-α production in sarcoidosis compared to purified protein derivative (PPD)-negative healthy control subjects. PBMCs from patients with sarcoidosis showed reduced IFN-γ producing T-cells following stimulation with CMV lysate, CEF peptides and CD3/CD28 beads; and reduced IL-4 and TNF-α production following CD3/CD28 activation.ConclusionsPatients with sarcoidosis exhibit greater PBMC responses to M. tuberculosis antigens compared to PPD-negative controls, but reduced T-cell responses to common recall antigens. One contributing mechanism may be impairment of T-cell CD28 co-stimulation