11,903 research outputs found
On the c-theorem in more than two dimensions
Several pieces of evidence have been recently brought up in favour of the
c-theorem in four and higher dimensions, but a solid proof is still lacking. We
present two basic results which could be useful for this search: i) the values
of the putative c-number for free field theories in any even dimension, which
illustrate some properties of this number; ii) the general form of three-point
function of the stress tensor in four dimensions, which shows some physical
consequences of the c-number and of the other trace-anomaly numbers.Comment: Latex, 7 pages, 1 tabl
Measuring walking accessibility to public transport for the elderly: the case of Naples
Demographic ageing represents an essential challenge for local authorities and public transport providers. Decision-makers should not ignore the speci c needs of this weak segment of the population and should implement appropriate policies. This paper develops a GIS-based method to analyse public transport accessibility of elderly people to support policies and planning strategies. To test the proposed method, we propose an application to the city of Naples in Italy. We selected this study case because it represents an example of high population density, complex urban structure and low level of quality of life, especially for the elderly. The application to the city of Naples showed that the urban accessibility changes dramatically for different age segments. Results also reveal patterns of public transport coverage that are signi cantly low particularly in suburban settings. The structure of this paper is organised into four sections: in the rst section, we introduce the main topic of mobility of elderly; in the second section, we describe and discuss the GIS-based method proposed; in the third section, we report on the application to the city of Naples; in the last section, we analyse the results and discuss future research developments
ATLAS RPC offline monitoring and data quality assessment
In this work several aspects of ATLAS RPC offline monitoring and data quality
assessment are illustrated with cosmics data selected by RPC trigger. These
correspond to trigger selection, front-end mapping, detection efficiency and
occupancy, which are studied in terms of low level quantities such as: RPC
off-line hits and standalone tracks. The tools and techniques presented are
also extended to the forthcoming LHC p-p beam collisions.Comment: Poster section at ICHEP08, Philadelphia, USA, July 2008. 3 pages,
LaTeX, 3 eps figure
Critical renormalized coupling constants in the symmetric phase of the Ising models
Using a novel finite size scaling Monte Carlo method, we calculate the four,
six and eight point renormalized coupling constants defined at zero momentum in
the symmetric phase of the three dimensional Ising system. The results of the
2D Ising system that were directly measured are also reported. Our values of
the six and eight point coupling constants are significantly different from
those obtained from other methods.Comment: 7 pages, 2 figure
Contraceptive use and sexual function: a comparison of Italian female medical students and women attending family planning services
Objectives: The aims of the study were to understand how education relates to contraceptive choice and how sexual function can vary in relation to the use of a contraceptive method. Methods: We surveyed female medical students and women attending a family planning service (FPS) in Italy. Participants completed an online questionnaire which asked for information on sociodemographics, lifestyle, sexuality and contraceptive use and also included items of the Female Sexual Function Index (FSFI). Results: The questionnaire was completed by 413 women (362 students and 51 women attending the FPS) between the ages of 18 and 30 years. FSFI scores revealed a lower risk of sexual dysfunction among women in the control group who did not use oral hormonal contraception. The differences in FSFI total scores between the two study groups, when subdivided by the primary contraceptive method used, was statistically significant (p < 0.005). Women using the vaginal ring had the lowest risk of sexual dysfunction, compared with all other women, and had a positive sexual function profile. In particular, the highest FSFI domain scores were lubrication, orgasm and satisfaction, also among the control group. Expensive contraception, such as long-acting reversible contraception, was not preferred by this young population, even though such methods are more contemporary and manageable. Compared with controls, students had lower compliance with contraception and a negative attitude towards voluntary termination of pregnancy. Conclusion: Despite their scientific knowledge, Italian female medical students were found to need sexual and contraceptive assistance. A woman's sexual function responds to her awareness of her body and varies in relation to how she is guided in her contraceptive choice. Contraceptive counselling is an excellent means to improve female sexuality
GRB970228 and the class of GRBs with an initial spikelike emission: do they follow the Amati relation?
On the basis of the recent understanding of GRB050315 and GRB060218, we
return to GRB970228, the first Gamma-Ray Burst (GRB) with detected afterglow.
We proposed it as the prototype for a new class of GRBs with "an occasional
softer extended emission lasting tenths of seconds after an initial spikelike
emission". Detailed theoretical computation of the GRB970228 light curves in
selected energy bands for the prompt emission are presented and compared with
observational BeppoSAX data. From our analysis we conclude that GRB970228 and
likely the ones of the above mentioned new class of GRBs are "canonical GRBs"
have only one peculiarity: they exploded in a galactic environment, possibly
the halo, with a very low value of CBM density. Here we investigate how
GRB970228 unveils another peculiarity of this class of GRBs: they do not
fulfill the "Amati relation". We provide a theoretical explanation within the
fireshell model for the apparent absence of such correlation for the GRBs
belonging to this new class.Comment: 5 pages, 3 figures, in the Proceedings of the "4th Italian-Sino
Workshop on Relativistic Astrophysics", held in Pescara, Italy, July 20-28,
2007, C.L. Bianco, S.-S. Xue, Editor
Densificare le aree metropolitane? Le frange urbane come città potenziali.Infrastrutture tra densità e dispersione nel sistema territoriale tra Nola e Napoli
New Algorithm of the Finite Lattice Method for the High-temperature Expansion of the Ising Model in Three Dimensions
We propose a new algorithm of the finite lattice method to generate the
high-temperature series for the Ising model in three dimensions. It enables us
to extend the series for the free energy of the simple cubic lattice from the
previous series of 26th order to 46th order in the inverse temperature. The
obtained series give the estimate of the critical exponent for the specific
heat in high precision.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Letter
A new class of short distance universal amplitude ratios
We propose a new class of universal amplitude ratios which involve the first
terms of the short distance expansion of the correlators of a statistical model
in the vicinity of a critical point. We will describe the critical system with
a conformal field theory (UV fixed point) perturbed by an appropriate relevant
operator. In two dimensions the exact knowledge of the UV fixed point allows
for accurate predictions of the ratios and in many nontrivial integrable
perturbations they can even be evaluated exactly. In three dimensional O(N)
scalar systems feasible extensions of some existing results should allow to
obtain perturbative expansions for the ratios. By construction these universal
ratios are a perfect tool to explore the short distance properties of the
underlying quantum field theory even in regimes where the correlation length
and one point functions are not accessible in experiments or simulations.Comment: 8 pages, revised version, references adde
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