6,790 research outputs found
Power calculation for gravitational radiation: oversimplification and the importance of time scale
A simplified formula for gravitational-radiation power is examined. It is
shown to give completely erroneous answers in three situations, making it
useless even for rough estimates. It is emphasized that short timescales, as
well as fast speeds, make classical approximations to relativistic calculations
untenable.Comment: Three pages, no figures, accepted for publication in Astronomische
Nachrichte
The Portuguese Radical Left Parties Supporting Government: From Policy-Takers to Policymakers?
How do parties that have long been confined to opposition behave once they take the decision
to support government? This article analyses the case of the three Portuguese radical
left parties that took such a move in the wake of the post-bailout 2015 election. Leveraging
the concept of contract parliamentarism and the analysis of different data sources through
different methods, we show that the three parties adopted a similar strategy after agreeing
deals with the centre-left socialists. Specifically, while keeping close scrutiny on the executive
action, the parties have voted consensually on most of the legislation proposed by the
government. In exchange, the majority of policy pledges agreed with the socialists were
implemented by the beginning of the legislature. Based on these findings, the article
underlines the importance for supporting parties of conducting a thorough negotiation
of policy goals and the timing of their implementation before joining the government,
and of pursuing an autonomous discursive agenda
Droplet minimizers for the Gates-Lebowitz-Penrose free energy functional
We study the structure of the constrained minimizers of the
Gates-Lebowitz-Penrose free-energy functional ,
non-local functional of a density field , , a
-dimensional torus of side length . At low temperatures, is not convex, and has two distinct global minimizers,
corresponding to two equilibrium states. Here we constrain the average density
L^{-d}\int_{{\cal T}_L}m(x)\dd x to be a fixed value between the
densities in the two equilibrium states, but close to the low density
equilibrium value. In this case, a "droplet" of the high density phase may or
may not form in a background of the low density phase, depending on the values
and . We determine the critical density for droplet formation, and the
nature of the droplet, as a function of and . The relation between the
free energy and the large deviations functional for a particle model with
long-range Kac potentials, proven in some cases, and expected to be true in
general, then provides information on the structure of typical microscopic
configurations of the Gibbs measure when the range of the Kac potential is
large enough
Regularity of higher codimension area minimizing integral currents
This lecture notes are an expanded version of the course given at the
ERC-School on Geometric Measure Theory and Real Analysis, held in Pisa,
September 30th - October 30th 2013. The lectures aim to explain the main steps
of a new proof of the partial regularity of area minimizing integer rectifiable
currents in higher codimension, due originally to F. Almgren, which is
contained in a series of papers in collaboration with C. De Lellis (University
of Zurich).Comment: This text will appear in "Geometric Measure Theory and Real
Analysis", pp. 131--192, Proceedings of the ERC school in Pisa (2013), L.
Ambrosio Ed., Edizioni SNS (CRM Series
Incumbents, opposition and international lenders: governing Portugal in times of crisis
The Portuguese case provides a unique opportunity to study the opposition's behaviour in a variety of political conditions. It offers an insight into the impact of the financial crisis on the opposition's behaviour in both majority and minority political settings. It allows the comparison of the opposition's relationship with a minority government, during which non-collaboration could have dramatic consequences, and also with a majority government, when such a choice does not have major political or policy implications. Moreover, it enables us to study the effect of an additional veto player (the so-called troika composed of the European Commission, the European Central Bank and the International Monetary Fund), which not only constrains both majority and opposition parties, but also gives political entrepreneurs a unique opportunity to push ahead with liberal measures \u2013 in this case, clearly in disagreement with the moderate and radical left programmes. Relying on quantitative data on the legislative behaviour of the parliamentary party groups in the period 1995\u20132012, and on qualitative process-tracking of the opposition's positions on key economic issues \u2013 such as the decision to vote against Prime Minister S\uf3crates' last austerity package after a series of approvals \u2013 this article aims to determine whether, and if yes how, the financial crisis has affected the behaviour of the Portuguese opposition parties in parliament, by examining and comparing their behaviour in hard and in normal times
Preferential association of hepatitis C virus with CD19+ B cells is mediated by complement system
Extrahepatic disease manifestations are common in chronic hepatitis C virus (HCV) infection. The mechanism of HCV-related lymphoproliferative disorders is not fully understood. Recent studies have found that HCV in peripheral blood mononuclear cells (PBMCs) from chronically infected patients is mainly associated with CD19+ B cells. To further elucidate this preferential association of HCV with B cells, we used in vitro cultured virus and uninfected PBMCs from healthy blood donors to investigate the necessary serum components that activate the binding of HCV to B cells. First, we found that the active serum components were present not only in HCV carriers, but also in HCV recovered patients and HCV negative healthy blood donors and that the serum components were heat labile. Second, the preferential binding activity of HCV to B cells could be blocked by anti-complement C3 antibodies. In experiments with complement-depleted serum and purified complement proteins, we demonstrated that complement proteins C1, C2, and C3 were required to activate such binding activity. Complement protein C4 was partially involved in this process. Third, using antibodies against cell surface markers, we showed that the binding complex mainly involved CD21 (complement receptor 2), CD19, CD20, and CD81; CD35 (complement receptor 1) was involved but had lower binding activity. Fourth, both anti-CD21 and anti-CD35 antibodies could block the binding of patient-derived HCV to B cells. Fifth, complement also mediated HCV binding to Raji cells, a cultured B cell line derived from Burkitt´s lymphoma.CONCLUSION:In chronic HCV infection, the preferential association of HCV with B cells is mediated by the complement system, mainly through complement receptor 2 (CD21), in conjunction with the CD19 and CD81 complex. This article is protected by copyright. All rights reserved.Fil: Wang, Richard. National Institutes of Health; Estados UnidosFil: Baré, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. National Institutes of Health; Estados UnidosFil: De Giorgi, Valeria. National Institutes of Health; Estados UnidosFil: Matsuura, Kentaro. Nagoya City University Graduate School of Medicine; Japón. National Institutes of Health; Estados UnidosFil: Salam, Kazi Abdus. National Institutes of Health; Estados Unidos. University of Rajshahi; IndiaFil: Grandinetti, Teresa. National Institutes of Health; Estados UnidosFil: Schechterly, Cathy. National Institutes of Health; Estados UnidosFil: Alter, Harvey J.. National Institutes of Health; Estados Unido
The cost of an ALP solution to the neutral -anomalies
The neutral anomalies in decays are analysed in terms of the tree-level
exchange of an axion-like-particle (ALP), within the effective field theory
framework. The complete two-dimensional parameter space for ALP couplings to
electrons and muons is explored. The solutions to and to the two energy
bins of are confronted with the impact of ALP exchange on other
observables (meson oscillations, leptonic and semileptonic decays of mesons
including searches for new resonances, astrophysical constraints), as well as
with the theoretical domain of validity of the effective theory. Solutions
based on ALPs heavier than mesons, or lighter than twice the muon mass, are
shown to be excluded. In contrast, the exchange of on-shell ALPs provides
solutions to and/or within sensitivity which are
technically compatible with those constraints; these solutions can be in
addition compatible with the data on the of the electron but not
simultaneously with those on the of the muon. Furthermore, a ''golden ALP
mass'' is identified at the frontier between the two energy bin windows of
, which could simultaneously explain these two
anomalies together with ; this calls for the convenience of different
energy binning which would easily clear up this (unlikely) possibility. The
impact of smearing on data analysis is also discussed.Comment: 50 pages, 15 figure
Polarization Response in InAs Quantum Dots: Theoretical Correlation between Composition and Electronic Properties
III-V growth and surface conditions strongly influence the physical structure
and resulting optical properties of self-assembled quantum dots (QDs). Beyond
the design of a desired active optical wavelength, the polarization response of
QDs is of particular interest for optical communications and quantum
information science. Previous theoretical studies based on a pure InAs QD model
failed to reproduce experimentally observed polarization properties. In this
work, multi-million atom simulations are performed to understand the
correlation between chemical composition and polarization properties of QDs. A
systematic analysis of QD structural parameters leads us to propose a two layer
composition model, mimicking In segregation and In-Ga intermixing effects. This
model, consistent with mostly accepted compositional findings, allows to
accurately fit the experimental PL spectra. The detailed study of QD morphology
parameters presented here serves as a tool for using growth dynamics to
engineer the strain field inside and around the QD structures, allowing tuning
of the polarization response.Comment: 8 pages, 6 figures; accepted for publication in IOP Nanotechnology
journa
Ultrafast control of Rabi oscillations in a polariton condensate
We report the experimental observation and control of space and time-resolved
light-matter Rabi oscillations in a microcavity. Our setup precision and the
system coherence are so high that coherent control can be implemented with
amplification or switching off of the oscillations and even erasing of the
polariton density by optical pulses. The data is reproduced by a fundamental
quantum optical model with excellent accuracy, providing new insights on the
key components that rule the polariton dynamics.Comment: 5 pages, 3 figures, supplementary 7 pages, 4 figures. Supplementary
videos:
https://drive.google.com/folderview?id=0B0QCllnLqdyBNjlMLTdjZlNhbTQ&usp=sharin
Pharmacokinetic profiles of the analgesic drug flupirtine in cats
Flupirtine (FLU) is a non-opioid analgesic drug with no antipyretic or antiphlogistic effects, used in the treatment of a wide range of pain states in human beings. There is a substantial body of evidence on the efficacy of FLU in humans but this is inadequate to recommend its off-label use in veterinary clinical practice. The aim of this study was to evaluate the pharmacokinetic profiles of FLU after IV and PO administration in healthy cats. Six mixed breed adult cats were randomly assigned to two treatment groups using an open, single-dose, two-treatment, two-phase, paired, cross-over design (2 × 2 Latin-square). Group 1 (n = 3) received a single dose of 5 mg/kg of FLU injected IV into the jugular vein. Group 2 (n = 3) received the same dose via PO route. The wash out period was 1 week. Blood samples (1 mL) were collected at assigned times and plasma was then analysed by a validated HPLC method.No adverse effects at the point of injection and no behavioural changes or alterations in health parameters were observed in the animals during or after the study (up to 7 days after the full study). After IV administration, FLU was detectable in plasma up to 36 h. After PO administration, FLU plasma concentrations were lower than those following IV administration, but they were detectable over the same time range. The terminal part of both mean pharmacokinetic curves showed a similar trend of elimination. The oral bioavailability was approximately 40%. This is the first study of FLU in an animal species of veterinary interest and it could pave the way for the use of this active ingredient in the veterinary field
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