73 research outputs found

    The <i>Castalia</i> mission to Main Belt Comet 133P/Elst-Pizarro

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    We describe Castalia, a proposed mission to rendezvous with a Main Belt Comet (MBC), 133P/Elst-Pizarro. MBCs are a recently discovered population of apparently icy bodies within the main asteroid belt between Mars and Jupiter, which may represent the remnants of the population which supplied the early Earth with water. Castalia will perform the first exploration of this population by characterising 133P in detail, solving the puzzle of the MBC’s activity, and making the first in situ measurements of water in the asteroid belt. In many ways a successor to ESA’s highly successful Rosetta mission, Castalia will allow direct comparison between very different classes of comet, including measuring critical isotope ratios, plasma and dust properties. It will also feature the first radar system to visit a minor body, mapping the ice in the interior. Castalia was proposed, in slightly different versions, to the ESA M4 and M5 calls within the Cosmic Vision programme. We describe the science motivation for the mission, the measurements required to achieve the scientific goals, and the proposed instrument payload and spacecraft to achieve these

    Structural change and foreign direct investment : globalization and regional economic integration

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    This paper investigates flows of inward and outward foreign direct investment (FDI) and FDI-to-GDP ratios in a sample of 62 countries over a 30 year time span. Using several endogenous structural break procedures (allowing for one and two break points), we find that: (1) the great majority of the series have structural breaks in the last 15 years, (2) post-break FDI and FDI/GDP ratios are substantially higher than the pre-break values, and (3) most breaks seem to be related to globalization, regional economic integration, economic growth, or political instability. Static and dynamic panel-data analy- ses accounting for and/or addressing endogeneity, simultaneity, nonstationar- ity, heterogeneity and cross-sectional dependence show that FDI is negatively related to exchange rate volatility and GDP per capita, but positively related to some regional integration agreements, trade openness, GDP, and GDP growth. Most notably, the European Union is the only regional economic integration unit found to consistently have significant and positive effects on FDI.info:eu-repo/semantics/publishedVersio

    Mechanism of Action of Cyclophilin A Explored by Metadynamics Simulations

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    Trans/cis prolyl isomerisation is involved in several biological processes, including the development of numerous diseases. In the HIV-1 capsid protein (CA), such a process takes place in the uncoating and recruitment of the virion and is catalyzed by cyclophilin A (CypA). Here, we use metadynamics simulations to investigate the isomerization of CA's model substrate HAGPIA in water and in its target protein CypA. Our results allow us to propose a novel mechanistic hypothesis, which is finally consistent with all of the available molecular biology data

    Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at √s=8 TeV with the ATLAS detector

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    An analysis is presented of events containing jets including at least one b-tagged jet, sizeable missing transverse momentum, and at least two leptons including a pair of the same electric charge, with the scalar sum of the jet and lepton transverse momenta being large. A data sample with an integrated luminosity of 20.3 fb−1 of pp collisions at √s=8 TeV recorded by the ATLAS detector at the Large Hadron Collider is used. Standard Model processes rarely produce these final states, but there are several models of physics beyond the Standard Model that predict an enhanced rate of production of such events; the ones considered here are production of vector-like quarks, enhanced four-top-quark production, pair production of chiral b′-quarks, and production of two positively charged top quarks. Eleven signal regions are defined; subsets of these regions are combined when searching for each class of models. In the three signal regions primarily sensitive to positively charged top quark pair production, the data yield is consistent with the background expectation. There are more data events than expected from background in the set of eight signal regions defined for searching for vector-like quarks and chiral b′-quarks, but the significance of the discrepancy is less than two standard deviations. The discrepancy reaches 2.5 standard deviations in the set of five signal regions defined for searching for four-top-quark production. The results are used to set 95% CL limits on various models

    Search for pair production of vector-like top quarks in events with one lepton, jets, and missing transverse momentum in √s=13 TeV pp collisions with the ATLAS detector

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    The results of a search for vector-like top quarks using events with exactly one lepton, at least four jets, and large missing transverse momentum are reported. The search is optimised for pair production of vector-like top quarks in the Z(→νν) t + X decay channel. LHC pp collision data at a centre-of-mass energy of √s=13 TeV recorded by the ATLAS detector in 2015 and 2016 are used, corresponding to an integrated luminosity of 36.1 fb−1. No significant excess over the Standard Model expectation is seen and upper limits on the production cross-section of a vector-like T quark pair as a function of the T quark mass are derived. The observed (expected) 95% CL lower limits on the T mass are 870 GeV (890 GeV) for the weak-isospin singlet model, 1.05 TeV (1.06 TeV) for the weak-isospin doublet model and 1.16 TeV (1.17 TeV) for the pure Zt decay mode. Limits are also set on the mass as a function of the decay branching ratios, excluding large parts of the parameter space for masses below 1 TeV

    Religiosity and Income: A Panel Cointegration and Causality Analysis

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    In this paper we examine the long-run relationship between religiosity and income using retrospective data on church attendance rates for a panel of countries from 1925 to 1990. We employ panel cointegration and causality techniques to control for omitted variable and endogeneity bias and test for the direction of causality. We show that there exists a negative long-run relationship between the level of religiosity, measured by church attendance, and the level of income, measured by the log of GDP per capita. The result is robust to alternative estimation methods, potential outliers, sample selection, different measures of church attendance, and alternative specifications of the income variable. Long-run causality runs in both directions, higher income leads to declining religiosity and declining religiosity leads to higher income

    Search for the production of single vector-like and excited quarks in the Wt final state in pp collisions at s = 8 s=8 \sqrt{s}=8 TeV with the ATLAS detector

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