2,134 research outputs found

    On the International Spillovers of US Quantitative Easing

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    The paper analyses the global spillovers of the Federal Reserve's unconventional monetary policy measures. First, we find that Fed measures in the early phase of the crisis (QE1), but not since 2010 (QE2), were highly effective in lowering sovereign yields and raising equity markets in the US and globally across 65 countries. Yet Fed policies functioned in a procyclical manner for capital flows to emerging markets (EMEs) and a counter-cyclical way for the US, triggering a portfolio rebalancing across countries out of EMEs into US equity and bond funds under QE1, and in the opposite direction under QE2. Second, the impact of Fed operations, such as Treasury and MBS purchases, on portfolio allocations and asset prices dwarfed those of Fed announcements, underlining the importance of the market repair and liquidity functions of Fed policies. Third, we find no evidence that FX or capital account policies helped countries shield themselves from these US policy spillovers, but rather that responses to Fed policies are related to country risk. The results thus illustrate how US unconventional measures have contributed to portfolio reallocation as well as a re-pricing of risk in global financial markets

    Quantifying the Microvascular Origin of BOLD-fMRI from First Principles with Two-Photon Microscopy and an Oxygen-Sensitive Nanoprobe

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    The blood oxygenation level-dependent (BOLD) contrast is widely used in functional magnetic resonance imaging (fMRI) studies aimed at investigating neuronal activity. However, the BOLD signal reflects changes in blood volume and oxygenation rather than neuronal activity per se. Therefore, understanding the transformation of microscopic vascular behavior into macroscopic BOLD signals is at the foundation of physiologically informed noninvasive neuroimaging. Here, we use oxygen-sensitive two-photon microscopy to measure the BOLD-relevant microvascular physiology occurring within a typical rodent fMRI voxel and predict the BOLD signal from first principles using those measurements. The predictive power of the approach is illustrated by quantifying variations in the BOLD signal induced by the morphological folding of the human cortex. This framework is then used to quantify the contribution of individual vascular compartments and other factors to the BOLD signal for different magnet strengths and pulse sequences.National Institutes of Health (U.S.) (Grant P41RR14075)National Institutes of Health (U.S.) (Grant R01NS067050)National Institutes of Health (U.S.) (Grant R01NS057198)National Institutes of Health (U.S.) (Grant R01EB000790)American Heart Association (Grant 11SDG7600037)Advanced Multimodal NeuroImaging Training Program (R90DA023427

    d-Polyarginine Lipopeptides as Intestinal Permeation Enhancers.

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    An estimated 285 million people were living with diabetes in 2010, and this number is expected to reach 440 million by 2030. Current treatment of this disease involves the intradermal injection of insulin analogues. Many alternative administration routes have been proposed, the oral route being the most widely studied. One of the most interesting approaches for insulin delivery is the use of permeation enhancers to increase its transport across the gastrointestinal tract (GIT). Cell‐penetrating peptides (CPPs) are a remarkable example of this family of compounds. Another alternative is the use of medium‐chain fatty acids (MCFAs) to temporally disrupt the tight junctions of the GIT, thereby allowing greater drug transport. A combination of both strategies can provide a synergistic way to increase drug transport through the GIT. In this study we evaluated the complexation of insulin glulisine, an insulin analogue administered subcutaneously or intravenously in clinical practice, with a well‐known CPP modified with the MCFA lauric acid. We prepared several formulations, examined their stability, and tested the best candidates in an intestinal cell‐based model. In particular, two compounds (C12‐r4 and C12‐r6) were found to significantly increase the transport of insulin, and therefore show promise as a new delivery system worthy of further evaluation

    Structural and biochemical characterization of the KLHL3-WNK kinase interaction important in blood pressure regulation

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    WNK1 [with no lysine (K)] and WNK4 regulate blood pressure by controlling the activity of ion co-transporters in the kidney. Groundbreaking work has revealed that the ubiquitylation and hence levels of WNK isoforms are controlled by a Cullin-RING E3 ubiquitin ligase complex (CRL3KLHL3) that utilizes CUL3 (Cullin3) and its substrate adaptor, KLHL3 (Kelch-like protein 3). Loss-of-function mutations in either CUL3 or KLHL3 cause the hereditary high blood pressure disease Gordon's syndrome by stabilizing WNK isoforms. KLHL3 binds to a highly conserved degron motif located within the C-terminal non-catalytic domain of WNK isoforms. This interaction is essential for ubiquitylation by CRL3KLHL3 and disease-causing mutations in WNK4 and KLHL3 exert their effects on blood pressure by disrupting this interaction. In the present study, we report on the crystal structure of the KLHL3 Kelch domain in complex with the WNK4 degron motif. This reveals an intricate web of interactions between conserved residues on the surface of the Kelch domain ÎČ-propeller and the WNK4 degron motif. Importantly, many of the disease-causing mutations inhibit binding by disrupting critical interface contacts. We also present the structure of the WNK4 degron motif in complex with KLHL2 that has also been reported to bind WNK4. This confirms that KLHL2 interacts with WNK kinases in a similar manner to KLHL3, but strikingly different to how another KLHL protein, KEAP1 (Kelch-like enoyl-CoA hydratase-associated protein 1), binds to its substrate NRF2 (nuclear factor-erythroid 2-related factor 2). The present study provides further insights into how Kelch-like adaptor proteins recognize their substrates and provides a structural basis for how mutations in WNK4 and KLHL3 lead to hypertension

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+→Ό+ÎœW^+ \rightarrow \mu^+\nu and W−→Ό−ΜW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Ethics, economics and the regulation and adoption of new medical devices: case studies in pelvic floor surgery

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    <p>Abstract</p> <p>Background</p> <p>Concern has been growing in the academic literature and popular media about the licensing, introduction and adoption of surgical devices before full effectiveness and safety evidence is available to inform clinical practice. Our research will seek empirical survey evidence about the roles, responsibilities, and information and policy needs of the key stakeholders in the introduction into clinical practice of new surgical devices for pelvic floor surgery, in terms of the underlying ethical principals involved in the economic decision-making process, using the example of pelvic floor procedures.</p> <p>Methods/Design</p> <p>Our study involves three linked case studies using, as examples, selected pelvic floor surgery devices representing Health Canada device safety risk classes: low, medium and high risk. Data collection will focus on stakeholder roles and responsibilities, information and policy needs, and perceptions of those of other key stakeholders, in seeking and using evidence about new surgical devices when licensing and adopting them into practice. For each class of device, interviews will be used to seek the opinions of stakeholders. The following stakeholders and ethical and economic principles provide the theoretical framework for the study:</p> <p indent="1"><b>Stakeholders </b>- federal regulatory body, device manufacturers, clinicians, patients, health care institutions, provincial health departments, and professional societies. Clinical settings in two centres (in different provinces) will be included.</p> <p indent="1"><b>Ethics </b>- beneficence, non-maleficence, autonomy, justice.</p> <p indent="1"><b>Economics </b>- scarcity of resources, choices, opportunity costs.</p> <p>For each class of device, responses will be analysed to compare and contrast between stakeholders. Applied ethics and economic theory, analysis and critical interpretation will be used to further illuminate the case study material.</p> <p>Discussion</p> <p>The significance of our research in this new area of ethics will lie in providing recommendations for regulatory bodies, device manufacturers, clinicians, health care institutions, policy makers and professional societies, to ensure surgical patients receive sufficient information before providing consent for pelvic floor surgery. In addition, we shall provide a wealth of information for future study in other areas of surgery and clinical management, and provide suggestions for changes to health policy.</p

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≄20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≀pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≀{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal
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