10,314 research outputs found
Noise and diffusion of particles obeying asymmetric exclusion processes
The relation between noise and Fick's diffusion coefficient in barrier
limited transport associated with hopping or tunneling mechanisms of particles
obeying the asymmetric simple exclusion processes (ASEP) is physically assessed
by Monte Carlo simulations. For a closed ring consisting of a large number of
barriers the diffusion coefficient is related explicitly to the current noise
thus revealing the existence of a generalized Nyquist-Einstein relation. Both
diffusion and noise are confirmed to decrease as the square root of the number
of barriers as a consequence of the correlation induced by ASEP. By contrast,
for an open linear chain of barriers the diffusion coefficient is found to be
no longer related to current noise. Here diffusion depends on particle
concentration but is independent of the number of barriers
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
A geogenic approach for the Radon monitoring and the exposure assessment at a regional scale: The results of the Rad_Campania project
Abstract. The aim of this paper is to analyse and discuss the
results of the regional program Rad Campania for the monitoring and the
assessment of the radon risk. An innovative methodology, based on a geogenic
approach, was developed, supported by a comprehensive campaign of radon
measurement performed in soil gas, natural waters, drinking natural water
samples and indoor air. Data refer to field measurements carried out in
three provinces of the Campania Region (Italy): Salerno, Avellino and
Benevento. The programme was completed with the main purpose to investigate
the peculiarities of the radon issue at a provincial scale and to redact a
map of the radon potential from soil as a tool for authorities to recognise
critical areas ("Radon prone areas") to monitor. Since the experience
demonstrates that the high radon potential from soil is not indicative of
high indoor radon concentrations, in this paper the authors have tried to
identify a possible general correlation between geological features of the
soil and structural characteristics of the buildings, elaborating more in
depth all data collected. The main purpose is to categorize and analyse the
performance of different kind of construction, typical of the local area, in
order to develop, in a future work, an indicator of the building
performances as a useful tool, for authorities, to recognise constructions
potentially more exposed to high indoor radon activity concentrations.
Results and perspectives have been discussed
A Monte Carlo study of the three-dimensional XY universality class:Universal amplitude ratios
We simulate lattice models in the three-dimensional XY universality class in
the low and the high temperature phase. This allows us to compute a number of
universal amplitude ratios with unprecedented precision: R_{\Upsilon}=0.411(2),
R_B=2.83(1), R_{\xi}^+=0.3562(10) and R_{\xi}^-=0.850(5). These results can be
compared with those obtained from other theoretical methods, such as field
theoretic methods or the high temperature series expansion and also with
experimental results for the lambda-transition of He. In addition to the XY
model, we study the three-dimensional two-component model on the
simple cubic lattice. The parameter of the model is chosen such that
leading corrections to scaling are small.Comment: 28 pages 5 figure
Densificare le aree metropolitane? Le frange urbane come città potenziali.Infrastrutture tra densità e dispersione nel sistema territoriale tra Nola e Napoli
High precision Monte Carlo study of the 3D XY-universality class
We present a Monte Carlo study of the two-component model on the
simple cubic lattice in three dimensions. By suitable tuning of the coupling
constant we eliminate leading order corrections to scaling. High
statistics simulations using finite size scaling techniques yield
and , where the statistical and
systematical errors are given in the first and second bracket, respectively.
These results are more precise than any previous theoretical estimate of the
critical exponents for the 3D XY universality class.Comment: 13 page
25th International Congress of the European Association for Endoscopic Surgery (EAES) Frankfurt, Germany, 14-17 June 2017 : Oral Presentations
Introduction: Ouyang has recently proposed hiatal surface area (HSA) calculation by multiplanar multislice computer tomography (MDCT) scan as a useful tool for planning treatment of hiatus defects with hiatal hernia (HH), with or without gastroesophageal reflux (MRGE). Preoperative upper endoscopy or barium swallow cannot predict the HSA and pillars conditions. Aim to asses the efficacy of MDCT’s calculation of HSA for planning the best approach for the hiatal defects treatment. Methods: We retrospectively analyzed 25 patients, candidates to laparoscopic antireflux surgery as primary surgery or hiatus repair concomitant with or after bariatric surgery. Patients were analyzed preoperatively and after one-year follow-up by MDCT scan measurement of esophageal hiatus surface. Five normal patients were enrolled as control group. The HSA’s intraoperative calculation was performed after complete dissection of the area considered a triangle. Postoperative CT-scan was done after 12 months or any time reflux symptoms appeared. Results: (1) Mean HSA in control patients with no HH, no MRGE was cm2 and similar in non-complicated patients with previous LSG and cruroplasty. (2) Mean HSA in patients candidates to cruroplasty was 7.40 cm2. (3) Mean HSA in patients candidates to redo cruroplasty for recurrence was 10.11 cm2. Discussion. MDCT scan offer the possibility to obtain an objective measurement of the HSA and the correlation with endoscopic findings and symptoms. The preoperative information allow to discuss with patients the proper technique when a HSA[5 cm2 is detected. During the follow-up a correlation between symptoms and failure of cruroplasty can be assessed. Conclusions: MDCT scan seems to be an effective non-invasive method to plan hiatal defect treatment and to check during the follow-up the potential recurrence. Future research should correlate in larger series imaging data with intraoperative findings
Metastatic melanoma cells with BRAF G469A mutation: nab‑paclitaxel better than vemurafenib?
Purpose BRAF G469A is a missense mutation within
exon 11 of the BRAF gene resulting in a constitutively
activated enzyme frequently associated with MAP kinase
cascade signaling activation. No evidence currently exists
about its role in determining sensitivity/resistance to BRAF
inhibitors, utilized in the treatment of patients carrying
BRAF V600 mutations, and to chemotherapy. The newly
established metastatic melanoma (MM) cell line MO-1 was
characterized for its sensitivity to vemurafenib and nabpaclitaxel, both already utilized for the treatment of MM.
Methods All analyses were carried out by comparing
results with those found in MM cells wild type for BRAF
or mutated in V600. In addition, cellular effectors were
investigated by ELISA kits, western blotting and flow
cytometry.
Results The exposure to vemurafenib inhibited MO-1 cell
proliferation at concentrations similar to those obtained in
vemurafenib-resistant melanoma models, and an explanation of this sensitivity is the strong activation of Erk1/2 .
and the low expression of MITF. Nab-paclitaxel strongly
reduced proliferation of MO-1 cells perhaps for the very
low expression level of PMEL17, transcriptionally regulated by MITF and negatively involved in determining sensitivity to taxanes.
Conclusions Thus, the mutation BRAF G469A in MM
might be related to a weak effectiveness of therapy with
BRAF inhibitors and a promising therapeutic approach
may be with nab-paclitaxel
TOPOLOGY OF THE ITALIAN AIRPORT NETWORK: A SCALE-FREE SMALL-WORLD NETWORK WITH A FRACTAL STRUCTURE?
Abstract
In this paper, for the first time we analyze the structure of the Italian Airport Network (IAN) looking at it as a mathematical
graph and investigate its topological properties. We find that it has very remarkable features, being like a scalefree
network, since both the degree and the ‘‘betweenness centrality’’ distributions follow a typical power-law known in
literature as a Double Pareto Law. From a careful analysis of the data, the Italian Airport Network turns out to have a
self-similar structure. In short, it is characterized by a fractal nature, whose typical dimensions can be easily determined
from the values of the power-law scaling exponents.
Moreover, we show that, according to the period examined, these distributions exhibit a number of interesting features,
such as the existence of some ‘‘hubs’’, i.e. in the graph theory’s jargon, nodes with a very large number of links,
and others most probably associated with geographical constraints.
Also, we find that the IAN can be classified as a small-world network because the average distance between reachable
pairs of airports grows at most as the logarithm of the number of airports. The IAN does not show evidence of
‘‘communities’’ and this result could be the underlying reason behind the smallness of the value of the clustering coefficient,
which is related to the probability that two nearest neighbors of a randomly chosen airport are connected
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
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