107 research outputs found
Bailouts in a common market: a strategic approach
Governments in the EU grant Rescue and Restructure Subsidies to bail out ailing firms. In an international asymmetric Cournot duopoly we study effects of such subsidies on market structure and welfare. We adopt a common market setting, where consumers from the two countries form one market. We show that the subsidy is positive also when it fails to prevent the exit. The reason is a strategic effect, which forces the more efficient firm to make additional cost-reducing effort. When the exit is prevented, allocative and productive efficiencies are lower and the only gaining player is the rescued firm
Generic tests of the existence of the gravitational dipole radiation and the variation of the gravitational constant
We present results from the high precision timing analysis of the
pulsar-white dwarf (WD) binary PSR J1012+5307 using 15 years of multi-telescope
data. Observations were performed regularly by the European Pulsar Timing Array
(EPTA) network, consisting of Effelsberg, Jodrell Bank, Westerbork and
Nan\c{c}ay. All the timing parameters have been improved from the previously
published values, most by an order of magnitude. In addition, a parallax
measurement of mas is obtained for the first time for PSR
J1012+5307, being consistent with the optical estimation from the WD companion.
Combining improved 3D velocity information and models for the Galactic
potential the complete evolutionary Galactic path of the system is obtained. A
new intrinsic eccentricity upper limit of is acquired,
one of the smallest calculated for a binary system and a measurement of the
variation of the projected semi-major axis also constrains the system's orbital
orientation for the first time. It is shown that PSR J1012+5307 is an ideal
laboratory for testing alternative theories of gravity. The measurement of the
change of the orbital period of the system of is used to set an upper limit on the dipole gravitational wave
emission that is valid for a wide class of alternative theories of gravity.
Moreover, it is shown that in combination with other binary pulsars PSR
J1012+5307 is an ideal system to provide self-consistent, generic limits, based
only on millisecond pulsar data, for the dipole radiation and the variation of
the gravitational constant .Comment: accepted for publication in MNRAS, 11 pages, 5 figures, 2 table
Timing stability of millisecond pulsars and prospects for gravitational-wave detection
Analysis of high-precision timing observations of an array of approx. 20
millisecond pulsars (a so-called "timing array") may ultimately result in the
detection of a stochastic gravitational-wave background. The feasibility of
such a detection and the required duration of this type of experiment are
determined by the achievable rms of the timing residuals and the timing
stability of the pulsars involved. We present results of the first long-term,
high-precision timing campaign on a large sample of millisecond pulsars used in
gravitational-wave detection projects. We show that the timing residuals of
most pulsars in our sample do not contain significant low-frequency noise that
could limit the use of these pulsars for decade-long gravitational-wave
detection efforts. For our most precisely timed pulsars, intrinsic
instabilities of the pulsars or the observing system are shown to contribute to
timing irregularities on a five-year timescale below the 100 ns level. Based on
those results, realistic sensitivity curves for planned and ongoing timing
array efforts are determined. We conclude that prospects for detection of a
gravitational-wave background through pulsar timing array efforts within five
years to a decade are good.Comment: 21 pages, 5 figures, submitted to MNRA
Measurement of the nuclear modification factor for muons from charm and bottom hadrons in Pb+Pb collisions at 5.02 TeV with the ATLAS detector
Heavy-flavour hadron production provides information about the transport properties and microscopic structure of the quark-gluon plasma created in ultra-relativistic heavy-ion collisions. A measurement of the muons from semileptonic decays of charm and bottom hadrons produced in Pb+Pb and pp collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV with the ATLAS detector at the Large Hadron Collider is presented. The Pb+Pb data were collected in 2015 and 2018 with sampled integrated luminosities of 208 mu b(-1) and 38 mu b(-1), respectively, and pp data with a sampled integrated luminosity of 1.17 pb(-1) were collected in 2017. Muons from heavy-flavour semileptonic decays are separated from the light-flavour hadronic background using the momentum imbalance between the inner detector and muon spectrometer measurements, and muons originating from charm and bottom decays are further separated via the muon track's transverse impact parameter. Differential yields in Pb+Pb collisions and differential cross sections in pp collisions for such muons are measured as a function of muon transverse momentum from 4 GeV to 30 GeV in the absolute pseudorapidity interval vertical bar eta vertical bar < 2. Nuclear modification factors for charm and bottom muons are presented as a function of muon transverse momentum in intervals of Pb+Pb collision centrality. The bottom muon results are the most precise measurement of b quark nuclear modification at low transverse momentum where reconstruction of B hadrons is challenging. The measured nuclear modification factors quantify a significant suppression of the yields of muons from decays of charm and bottom hadrons, with stronger effects for muons from charm hadron decays
A search for an unexpected asymmetry in the production of e+μ− and e−μ+ pairs in proton-proton collisions recorded by the ATLAS detector at root s = 13 TeV
This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for e(+)mu(-) and e(-)mu(+) pairs to constrain physics processes beyond the Standard Model. It uses 139 fb(-1) of proton-proton collision data recorded at root s = 13 TeV at the LHC. Targeting sources of new physics which prefer final states containing e(+)mu(-) and e(-)mu(+), the search contains two broad signal regions which are used to provide model-independent constraints on the ratio of cross sections at the 2% level. The search also has two special selections targeting supersymmetric models and leptoquark signatures. Observations using one of these selections are able to exclude, at 95% confidence level, singly produced smuons with masses up to 640 GeV in a model in which the only other light sparticle is a neutralino when the R-parity-violating coupling lambda(23)(1)' is close to unity. Observations using the other selection exclude scalar leptoquarks with masses below 1880 GeV when g(1R)(eu) = g(1R)(mu c) = 1, at 95% confidence level. The limit on the coupling reduces to g(1R)(eu) = g(1R)(mu c) = 0.46 for a mass of 1420 GeV
Search for supersymmetry in final states with two same-sign or three leptons and jets using 36 fb−1 of √s = 13 TeV pp collision data with the ATLAS detector
A search for strongly produced supersymmetric particles using signatures involving multiple energetic jets and either two isolated same-sign leptons (e or μ), or at least three isolated leptons, is presented. The analysis relies on the identification of b-jets and high missing transverse momentum to achieve good sensitivity. A data sample of proton-proton collisions at s√=13 TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 and 2016, corresponding to a total integrated luminosity of 36.1 fb−1, is used for the search. No significant excess over the Standard Model prediction is observed. The results are interpreted in several simplified supersymmetric models featuring R-parity conservation or R-parity violation, extending the exclusion limits from previous searches. In models considering gluino pair production, gluino masses are excluded up to 1.87 TeV at 95% confidence level. When bottom squarks are pair-produced and decay to a chargino and a top quark, models with bottom squark masses below 700 GeV and light neutralinos are excluded at 95% confidence level. In addition, model-independent limits are set on a possible contribution of new phenomena to the signal region yields
Sinking Budgets and Ballooning Prices: Recent Developments Connected to Military Spending
Military spending in the West generally declined after the Cold War. Given the economic pressures that many of these states confronted, they can be said to have experienced a fortuitous conjunction of lessening security demands with stable if not rising pressures to allocate more resources to social purposes. However, with declining financial resources a good part of military capital in these countries was reduced and most of what remains is growing obsolete. The excessive rise in relative prices associated with major military capital items, a rise only partially associated with an increase in real effectiveness, poses a challenge for many of these states if they are to retain their capacity to provide in some meaningful way for their own military defense.Nach Ende des Kalten Krieges sind allgemein in der westlichen Welt die Militärausgaben gesunken. Angesichts des wirtschaftlichen Drucks, dem sich viele dieser Länder ausgesetzt sahen, kann man sagen, dass dies Ergebnis eines zufälligen Zusammentreffens mehrerer Faktoren ist: geringere Sicherheitsanforderungen treffen auf gleich bleibende bzw. sogar zunehmende Forderungen nach alternativer Budgetverwendung, beispielsweise mehr Mittelausgaben für soziale Zwecke. Durch die verringerten Finanzmittel für die Verteidigung wurde jedoch ein großer Teil der militärischen Waffensysteme reduziert, der verbliebene Rest ist zum größten Teil veraltet. Die relativen Preise für Waffensysteme sind jedoch exzessiv gestiegen, ohne dass diese auf einem gleich großen Anstieg der tatsächlichen Effektivität der Waffensysteme beruhen. So stellt es für viele dieser Staaten eine große Herausforderung dar, wenn sie ihre Fähigkeit bewahren wollen, auf sinnvolle Weise für ihre eigene militärische Sicherheit zu sorgen
Risks at Work: The Demand and Supply Sides of Government Redistribution
To understand how the welfare state adjusts to economic shocks it is important to explain both the genesis of popular preferences and the institutional incentives of governments to respond to these preferences. This paper attempts to do both, using a general theoretical framework and detailed data at both the individual and national levels. In a first step, we focus on how risk exposure and income are related to preferences for redistribution. To test our hypotheses, we extract detailed risk exposure measures from labor force surveys and marry them to cross-national survey data. In a second step, we turn our attention to the supply side of government redistribution. Institutions, we argue, mediate governments’ reactions to redistributional demands following economic shocks. Using time-series cross-country data, we demonstrate how national training systems, electoral institutions as well as government partisanship shape government responses.Um zu verstehen, wie Wohlfahrtsstaaten auf ökonomische Schocks reagieren, ist es wichtig, sowohl die Nachfrage- als auch die Angebotsseite von Umverteilung zu analysieren. Wie entstehen Umverteilungs-Präferenzen in der Bevölkerung? Welche institutionellen Anreize haben Regierungen, darauf zu reagieren? Das vorliegende Papier wendet einen generellen theoretischen Rahmen und umfangreiche Individual- und Aggregat-Daten an, um diesen Fragen nachzugehen. Dazu wird zuerst analysiert, wie Risiken im Arbeitsmarkt und das Einkommen Umverteilungs-Präferenzen von Individuen beeinflussen. Die abgeleiteten Hypothesen werden an neuen Datensätzen getestet. Diese kombinieren Informationen von Arbeitsmarkterhebungen und Umfrage-Daten für mehrere Länder und Jahre. In Sachen Angebotsseite wird argumentiert, dass unterschiedliche Regierungen auf ökonomische Schocks unterschiedlich reagieren, abhängig von Institutionen. Das Papier testet diese und andere Hypothesen auf der Aggregatsebene anhand von vergleichenden Zeitreihen. Es zeigt sich, dass die Art und Weise, wie Regierungen auf ökonomische Schocks reagieren, von Ausbildungs- und Wahlsystemen sowie der parteipolitischen Färbung der Regierung mitbestimmt werden
You Don‘t Know What You‘ve Got Till It‘s Gone! Unemployment and Intertemporal Changes in Self-Reported Life Satisfaction
This paper uses concurrently and - for the first time - retrospectively reported life satisfaction from the 1984 to 1987 waves of the German Socio-Economic Panel to study the importance of different comparison standards for the empirical correlation of unemployment and subjective life satisfaction. It is found that unemployed individuals do not only report significantly lower concurrent satisfaction, but also recall reduced satisfaction from past unemployment well, and retrospectively upgrade their past satisfaction scores. Therefore, the short-term negative effects of unemployment on individual life satisfaction reported in the literature so far are likely underestimated. At the same time, the empirical findings cast doubts on the usefulness of subjective life satisfaction for the precise quantification of welfare effects because of changing comparison standards which greatly limit the intertemporal comparability of the data. For this reason, such data also appear to be of limited use for monitoring long-term economic or social development.Diese Studie untersucht den Einfluss verschiedener Vergleichsstandards auf die empirische Korrelation von Arbeitslosigkeit und individueller Lebenszufriedenheit. Dafür werden sowohl longitudinale als auch retrospektive Daten zur subjektiven Lebenszufriedenheit des Deutschen Sozio-ökonomischen Panels aus den Jahren 1984 bis 1987 ausgewertet. Es wird gezeigt, dass Arbeitslose nicht nur zum Zeitpunkt ihrer Arbeitslosigkeit eine geringere Lebenszufriedenheit angeben, sondern sich später auch gut an diese geringere Zufriedenheit erinnern und retrospektiv frühere Angaben zur Lebenszufriedenheit nach oben korrigieren. Die bisher in der Literatur genannten kurzfristigen negativen Effekte von Arbeitslosigkeit auf das individuelle Wohlergehen sind daher wahrscheinlich unterschätzt worden. Allerdings deuten die empirischen Ergebnisse dieser Studie auch darauf hin, dass Daten zur subjektiven Lebenszufriedenheit nur sehr bedingt dazu geeignet sind, Wohlfahrtseffekte zu quantifizieren, da sich die individuellen Evaluationsstandards im Zeitablauf ändern. Aus diesem Grund erscheinen solche Daten auch ungeeignet, um längerfristige sozio-ökonomische Entwicklungen zu beobachten oder zu analysieren
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