14,035 research outputs found
Experimental effects on dynamics and thermodynamics in nuclear reactions on the symmetry energy as seen by the CHIMERA 4 detector
Heavy ion collisions have been widely used in the last decade to constraint
the parameterizations of the symmetry energy term of nuclear equation of state
(EOS) for asymmetric nuclear matter as a function of baryonic density. In the
Fermi energy domain one is faced with variations of the density within a narrow
range of values around the saturation density =0.16 fm down
towards sub-saturation densities. The experimental observables which are
sensitive to the symmetry energy are constructed starting from the detected
light particles, clusters and heavy fragments that, in heavy ion collisions,
are generally produced by different emission mechanisms at different stages and
time scales of the reaction. In this review the effects of dynamics and
thermodynamics on the symmetry energy in nuclear reactions are discussed and
characterized using an overview of the data taken so far with the CHIMERA
multi-detector array.Comment: 21 pages, 25 figures. Review to appear in EPJA special volume on
nuclear symmetry energ
Sharing Default Information as a Borrower Discipline Device
Creditors often share information about their customers' credit record. Besides helping them to spot bad risks, this informational exchange acts as a disciplinary device. If creditors are known to exchange data about defaults, borrowers must consider that default on a current lender would disrupt their credit rating with all the other lenders. This raises their incentive to perform. But sharing more detailed information can reduce this disciplinary effect: when lenders only disclose past defaults, borrowers' incentives to perform may be greater than when lenders share all their information. In some instances, by "fine-tuning" the type and accuracy of the information shared, lenders can raise borrowers' incentives to their first-best level.Fiscal policy, national saving, contractionary fiscal expansions
Noise-induced dephasing of an ac-driven Josephson junction
We consider phase-locked dynamics of a Josephson junction driven by
finite-spectral-linewidth ac current. By means of a transformation, the effect
of frequency fluctuations is reduced to an effective additive noise, the
corresponding (large) dephasing time being determined, in the logarithmic
approximation, by the Kramers' expression for the lifetime. For sufficiently
small values of the drive's amplitude, direct numerical simulations show
agreement of the dependence of the dephasing activation energy on the
ac-drive's spectral linewidth and amplitude with analytical predictions.
Solving the corresponding Fokker-Planck equation analytically, we find a
universal dependence of a critical value of the effective phase-diffusion
parameter on the drive's amplitude at a point of a sharp transition from the
phase-locked state to an unlocked one. For large values of the drive amplitude,
saturation and subsequent decrease of the activation energy are revealed by
simulations, which cannot be accounted for by the perturbative analysis. The
same new effect is found for a previously studied case of ac-driven Josephson
junctions with intrinsic thermal noise. The work was performed in the framework
of a cooperation agreement between Consiglio Nazionale di Ricerca (Italy) and
the Israeli Ministry of Science and Technology.Comment: latex text file and six eps figure files. Physical Review E, in pres
The quality of price formation at market openings and closings: evidence from the Nasdaq stock market
Central counterparties (CCPs) have increasingly become a cornerstone of financial markets infrastructure. We present a model where trades are time-critical, liquidity is limited and there is limited enforcement of trades. We show a CCP novating trades implements efficient trading behaviour. It is optimal for the CCP to face default losses to achieve the efficient level of trade. To cover these losses, the CCP optimally uses margin calls, and, as the default problem becomes more severe, also requires default funds and then imposes position limits
Afro-Brazilian Religions and Ethnic Identity Politics in the Brazilian Public Health Arena
In this article, I examine the ways in which health activists from Afro-Brazilian religions deploy ethnic identity politics within the Brazilian public health arena to gain recognition and respect for their beliefs and practices, as well as public health goods for their communities. I also discuss the creation and enactment of “culturally competent” healthcare initiatives for members of Afro-Brazilian religions. Finally, I examine the tension between universal particular identity frames that emerges within the political discourses of health activists from Afro-Brazilian religions. Throughout, I place this case study in dialogue with similar scholarship on minority health politics and cultural competence initiatives in other parts of the world
Doppler imaging of the young late-type star LO Pegasi (BD +22 4409) in September 2003
A Doppler image of the ZAMS late-type rapidly rotating star LO Pegasi, based
on spectra acquired between 12 and 15 September 2003, is presented. The Least
Square Deconvolution technique is applied to enhance the signal-to-noise ratio
of the mean rotational broadened line profiles extracted from the observed
spectra. In the present application, a unbroadened spectrum is used as a
reference, instead of a simple line list, to improve the deconvolution
technique applied to extract the mean profiles. The reconstructed image is
similar to those previously obtained from observations taken in 1993 and 1998,
and shows that LO Peg photospheric activity is dominated by high-latitude spots
with a non-uniform polar cap. The latter seems to be a persistent feature as it
has been observed since 1993 with little modifications. Small spots, observed
between ~ 10 and ~ 60 degrees of latitude, appears to be different with respect
to those present in the 1993 and 1998 maps.Comment: 21 pages, 10 figures, accepted by Monthly Notices of the Royal
Astronomical Societ
Los gobiernos locales en los Estados Unidos de América
Traducción de Z. LÓPEZ CÁRCAMO (IDL-UAM). El presente artículo tiene su origen en los trabajos preparatorios
del Seminario Internacional sobre gobiernos locales y estados federales organizado por el «Forum of
Federations» a lo largo de 2007. El texto de este escrito fue presentado por el autor en el Seminario organizado
por el Ayuntamiento de Madrid y el IDL-UAM el pasado 4 de abril de 2008Este estudio presenta una visión general del régimen de creación y consolidación de los distintos
tipos de gobiernos locales de la República Federal de los EE.UU. El autor realiza un recorrido
histórico que llega hasta el momento actual. En este recorrido se analizan las distintas
fases que han tenido que superar los gobiernos locales en sus relaciones políticas y financieras con
los gobiernos estatal y federal hasta conseguir una considerable autonomía. Asimismo, enfatiza
la relevancia del papel de estos gobiernos de cara a los ciudadanos en cuanto a la prestación de
servicios esenciales y los mecanismos utilizados para financiarlos. Finalmente, se plantean los
problemas y retos comunes que deben afrontar los gobiernos locales en el escenario de la economía
global en el que, para garantizar los servicios básicos de manera eficaz y eficiente, deben
adaptarse a nuevas formas de gestión, cooperación y colaboración público-privadaThis study outlines an overview of the system of creation and consolidation of the different
types of local governments in the Federal Republic of USA. The author goes through
history up to nowadays. On this trip the various phases of local governments concerning to
their political and financial relationships are being analysed, how they had to overcome
state and federal governments in order to achieve a considerable autonomy. It is also remarkable
the importance of the role of these governments when dealing with the citizens, supplying
them with the essential services and mechanisms used to finance them. Finally, the pro-
blems and challenges that local governments have to face up within the global economy
scene. To ensure basic services effectively and efficiently, they must adapt to new ways of
management, cooperation and public-private partnership
What Makes Stock Exchanges Succeed? Evidence from Cross-Listing Decisions
Despite the increasing integration of capital markets, geography has not yet become irrelevant to finance. Between 1986 and 1997, European public companies have increasingly listed abroad, especially in the U.S. We relate the cross-listing decisions to the characteristics of the destination exchanges (and countries) relative to those of the home exchange (and country). European companies appear more likely to cross-list in more liquid and larger markets, and in markets where several companies from their industry are already cross-listed. They are also more likely to cross-list in countries with better investor protection, and more efficient courts and bureaucracy, but not with more stringent accounting standards.cross-listings, going public, initial public offerings, geography, stock market competition
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