292 research outputs found
The role of damping for the driven anharmonic quantum oscillator
For the model of a linearly driven quantum anharmonic oscillator, the role of
damping is investigated. We compare the position of the stable points in phase
space obtained from a classical analysis to the result of a quantum mechanical
analysis. The solution of the full master equation shows that the stable points
behave qualitatively similar to the classical solution but with small
modifications. Both the quantum effects and additional effects of temperature
can be described by renormalizing the damping.Comment: 4 pages, 2 figures; submitted to "Journal of Physics: Conference
Series
Nonuniversal route to universality: Critical phenomena in colloidal dispersions
We investigate critical phenomena in colloids by means of the
renormalization-group based hierarchical reference theory of fluids (HRT). We
focus on three experimentally relevant model systems: namely, the
Asakura-Oosawa model of a colloidal dispersion under the influence of
polymer-induced attractive depletion forces; fluids with competing short-range
attractive and longer-range repulsive interactions; solutions of star-polymers
whose pair potential presents both an attractive well and an ultrasoft
repulsion at shorter distance. Our results show that the ability to tune the
effective interactions between colloidal particles allows one to generate a
variety of crossovers to the asymptotic critical behavior, which are not
observed in atomic fluids.Comment: 4 pages, 3 figure
Screening for Latent Tuberculosis Infection among Students of Healthcare Professions and Postgraduates of the Faculty of Medicine of the University of Palermo
Introduction and objective: Italy is a country with a low incidence of tuberculosis and in the last fifty years the annual number of TB cases decreased from 12,247 to 4,418, showing a reduction of approximately 64% in the number of cases and 71% in incidence. Despite of this encouraging trend, in the last years the epidemiology of tuberculosis changed and today it is a re-emerging infectious. The aim of this study is to measure the prevalence of positivity to tuberculosis infection (latent TB) in students, without any obvious manifestation of disease, attending degree courses of the health care professions and postgraduate medical courses of the School of Medicine of the University of Palermo, Italy.
Materials and methods: A cross-sectional observational study in students of nursing, midwifery, dentistry degree courses and in resident physicians of postgraduate medical schools was carried out from January 2012 to July 2016.
Mantoux test was performed and all positive cases were tested with Interferon-Gamma Release Assay (IGRA).
Results: Of the 1,351 subjects evaluated, 25 (1.8%) resulted positive to Mantoux test; in 17 students (1.2%) the diagnosis was confirmed with IGRA. Positive cases were significantly more frequent among students attending Postgraduated Medical School Courses (p<0.001) and were older than negative cases (p<0.001).
Conclusion: This study suggests that in our geographic area, latent TB shows a relatively low prevalence among students of medical schools. Despite of this evidence, and considering that several students have been found to be
positive for TB, this infectious disease has to be considered a re-emerging biohazard that requires preventive strategies for the containment of the risk in exposed workers as well as in the general population
Ischemic cardiovascular disease in workers occupationally exposed to urban air pollution – A systematic review
Introduction. Cardiovascular disease is the first cause of morbidity and mortality worldwide. Among several known risk factors, researchers also focus their attention on the chronic exposure to air pollution. There is much evidence that exposure to air pollution, especially to ultrafine particles, can damage the endothelium and can favour cardiovascular diseases in the general population. Occupational exposition could be an additive risk factor for the cardiovascular system. This article presents a scientific review of the linkage between occupational exposure to air pollution and ischemic heart disease. Materials and method. A scientific review was undertaken, followed by PRISMA Statements. Observational studies were selected from several scientific databases, likesuch as Pubmed, Google Scholar, Nioshtic-2 and Reserchgate, searching
for selected key words: police workers, professional drivers, mail carriers, filling station attendants, road cleaners, garage workers, motor vehicles and engine maintenance. All the key words were combined with “Boolean Operators” with the
following words: cardiovascular (or cardiac) disease, cardiovascular function, cardiovascular system, ischemic heart disease, coronary disease, myocardial infarction. During the systematic research, the focus was on retrospective and prospective studies from January 1990 – December 2014.
Results. Both the retrospective and prospective studies showed an increased risk of ischemic heart disease in occupationally occupied people exposed to air pollution. Only one study presented a ly minor risk.
Conclusions. The findings of this systematic review suggest a possible linkage between occupational exposure to urban air pollution, especially to motor exhaust and particulate, and ischemic heart disease
Semiclassical theory of energy diffusive escape in a Duffing oscillator
Motivated by recent experimental progress to read out quantum bits
implemented in superconducting circuits via the phenomenon of dynamical
bifurcation, transitions between steady orbits in a driven anharmonic
oscillator, the Duffing oscillator, are analyzed. In the regime of weak
dissipation a consistent master equation in the semiclassical limit is derived
to capture the intimate relation between finite tunneling and reflection and
bath induced quantum fluctuations. From the corresponding steady state
distributions analytical expressions for the switching probabilities are
obtained. It is shown that a reduction of the transition rate due to finite
reflection at the phase-space barrier is overcompensated by an increase due to
environmental quantum fluctuations that are specific for diffusion processes
over dynamical barriers. Moreover, it is revealed that close to the bifurcation
threshold the escape dynamics enters an overdamped domain such that the quantum
mechanical energy scale associated with friction even exceeds the thermal
energy scale
Clinical characteristics and management of cancer-associated acute venous thromboembolism: findings from the MASTER Registry.
Background: Clinical characteristics and management of acute deep vein thrombosis and pulmonary embolism (PE) have been reported to be different in patients with and without cancer. The aim of this paper was to provide information on clinical characteristics and management of acute venous thromboembolism in patients with cancer by means of a large prospective registry. Design and Methods: MASTER is a multicenter registry of consecutively recruited patients with symptomatic, objectively confirmed, acute venous thromboembolism. Information about clinical characteristics and management was collected by an electronic data network at the time of the index event. Results: A total of 2119 patients were enrolled, of whom 424 (20%) had cancer. The incidence of bilateral lower limb deep vein thrombosis was significantly higher in patients with cancer than in patients without cancer (8.5% versus 4.6%; p<0.01), as were the rates of iliocaval thombosis (22.6% versus 14%; p<0.001), and upper limb deep vein thrombosis (9.9% versus 4.8%; p<0.001). Major bleeding (3.3% versus 1.1%; p=0.001), in-hospital treatment (73.3% versus 66.6%; p=0.02) and inferior vena cava filter implantation (7.3% versus 4.1%; p=0.005) were significantly more frequent in patients with cancer, in whom oral anticoagulants were less often used (64.2% versus 82%; p<0.0001). Conclusions: The clinical presentation of acute venous thromboembolism is different and often more extensive in cancer patients than in patients free from malignancy. Moreover, the management of the acute phase of venous thromboembolism is more problematic in cancer patients, especially because of a higher rate of major bleeding and the need for implantation of inferior vena cava filters
Critical behavior in colloid-polymer mixtures: theory and simulation
We extensively investigated the critical behavior of mixtures of colloids and
polymers via the two-component Asakura-Oosawa model and its reduction to a
one-component colloidal fluid using accurate theoretical and simulation
techniques. In particular the theoretical approach, hierarchical reference
theory [Adv. Phys. 44, 211 (1995)], incorporates realistically the effects of
long-range fluctuations on phase separation giving exponents which differ
strongly from their mean-field values, and are in good agreement with those of
the three-dimensional Ising model. Computer simulations combined with
finite-size scaling analysis confirm the Ising universality and the accuracy of
the theory, although some discrepancy in the location of the critical point
between one-component and full-mixture description remains. To assess the limit
of the pair-interaction description, we compare one-component and two-component
results.Comment: 15 pages, 10 figures. Submitted to Phys. Rev.
Photobioreactors as a Dynamic Shading System Conceived for an Outdoor Workspace of the State Library of Queensland in Brisbane: Study of Daylighting Performances
In the field of responsive shading systems, the use of photobioreactors (PBRs) containing microalgae seems to be a promising technology. Within this framework, this paper presents a case study where a PBR was specifically conceived as a shading system for an external workspace located on an open terrace of the State Library of Queensland (SLQ) in Brisbane. The proposed shading system makes use of PBRs as translucent screening elements, capable of regulating natural light to provide adequate visual comfort for a multi-purpose workspace, despite exposure of the site to direct sunlight and fluctuating weather conditions. The microalgae (Scenedesmus Obliquus) cultivated within the shading elements contribute to improving the environment by bio-sequestrating CO2 and producing oxygen. They are also a valuable raw material containing bioactive compounds with various applications including nutraceutical products, livestock feed, and biofuel synthesis. In addition, their green pigmentation is visually engaging and allows for the filtration of solar radiation. The paper focuses on analyzing the daylight performance in the outdoor workplace under the PBR shade. The biomass density of the PBR is adjustable across a wide range of light transmittances (10%-80%) to counter the highly variable outdoor conditions. For different Tv values, illuminance values were calculated using the simulation tool DIVA-for-Rhino and then analyzed as both point-in-time illuminance in June, September and December, and through climate-based daylight metrics such as the Daylight Autonomy and the Useful Daylight Illuminance. As a further step, the daylighting performances were compared to two other climates (Turin, Italy, and Dubai, United Arab Emirates), to verify which setting of the PBR may be suitable for different boundary conditions, thus making the system more widely applicable. The results in Brisbane showed that for clear sky conditions, higher levels of biomass saturation are needed (Tv < 20%) to remain in the 300-3000 lx 'optimal' illuminance comfort range, with lower concentrations (Tv < 30%) to remain within the 300-6000 lx 'acceptable' illuminance comfort range. Differently, in overcast sky conditions, the optimal range of illuminance is easily obtained with reduced levels of biomass saturation (Tv < 80%)
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