24 research outputs found
Group entropies, correlation laws and zeta functions
The notion of group entropy is proposed. It enables to unify and generalize
many different definitions of entropy known in the literature, as those of
Boltzmann-Gibbs, Tsallis, Abe and Kaniadakis. Other new entropic functionals
are presented, related to nontrivial correlation laws characterizing
universality classes of systems out of equilibrium, when the dynamics is weakly
chaotic. The associated thermostatistics are discussed. The mathematical
structure underlying our construction is that of formal group theory, which
provides the general structure of the correlations among particles and dictates
the associated entropic functionals. As an example of application, the role of
group entropies in information theory is illustrated and generalizations of the
Kullback-Leibler divergence are proposed. A new connection between statistical
mechanics and zeta functions is established. In particular, Tsallis entropy is
related to the classical Riemann zeta function.Comment: to appear in Physical Review
Multi-messenger Observations of a Binary Neutron Star Merger
On 2017 August 17 a binary neutron star coalescence candidate (later
designated GW170817) with merger time 12:41:04 UTC was observed through
gravitational waves by the Advanced LIGO and Advanced Virgo detectors.
The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray
burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to
the merger time. From the gravitational-wave signal, the source was
initially localized to a sky region of 31 deg2 at a
luminosity distance of {40}-8+8 Mpc and with
component masses consistent with neutron stars. The component masses
were later measured to be in the range 0.86 to 2.26 {M}ȯ
. An extensive observing campaign was launched across the
electromagnetic spectrum leading to the discovery of a bright optical
transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC
4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the
One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The
optical transient was independently detected by multiple teams within an
hour. Subsequent observations targeted the object and its environment.
Early ultraviolet observations revealed a blue transient that faded
within 48 hours. Optical and infrared observations showed a redward
evolution over ∼10 days. Following early non-detections, X-ray and
radio emission were discovered at the transient’s position ∼ 9
and ∼ 16 days, respectively, after the merger. Both the X-ray and
radio emission likely arise from a physical process that is distinct
from the one that generates the UV/optical/near-infrared emission. No
ultra-high-energy gamma-rays and no neutrino candidates consistent with
the source were found in follow-up searches. These observations support
the hypothesis that GW170817 was produced by the merger of two neutron
stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and
a kilonova/macronova powered by the radioactive decay of r-process
nuclei synthesized in the ejecta.</p
The Cost-Effectiveness of Vaccination of Older Adults with an MF59-Adjuvanted Quadrivalent Influenza Vaccine Compared to Other Available Quadrivalent Vaccines in Germany
Enhanced quadrivalent influenza vaccines that include an adjuvant (aQIV) or a high dose of antigen (QIV-HD), which stimulate a stronger immune response in older adults than the standard vaccine (QIVe), are now approved. The objective of this research is to compare available vaccines and determine the cost-effectiveness of immunizing persons aged 65 years and above with aQIV compared to QIVe and QIV-HD in Germany. A compartmental transmission model calibrated to outpatient visits for influenza in Germany was used to predict the number of medically attended infections using the three vaccines. The rates of hospitalizations, deaths, and other economic consequences were estimated with a decision tree using German data where available. Based on meta-analysis, the rVE of −2.5% to 8.9% for aQIV versus QIV-HD, the vaccines are similar clinically, but aQIV is cost saving compared to QIV-HD (unit cost of EUR 40.55). All results were most sensitive to changes in vaccine effectiveness. aQIV may be cost-effective compared to QIVe depending on the willingness to pay for additional benefits in Germany. As aQIV and QIV-HD are similar in terms of effectiveness, aQIV is cost saving compared to QIV-HD at current unit prices
Resource utilization and cost of treatment with anidulafungin or fluconazole for candidaemia and other forms of invasive candidiasis: focus on critically ill patients
Candidaemia and other forms of invasive candidiasis (C/IC) are serious and costly events for hospitalized patients, particularly those in the ICU. Both fluconazole and the echinocandins are recommended as first-line therapy for C/IC. Resource use and cost considerations are important in selecting appropriate treatment but little information is available on the economic implications of using echinocandins in this setting.
To compare resource utilization and treatment costs (in US2680 (p = 0.73). For hospitalized patients who survived (anidulafungin 81.9%, fluconazole 69.7%), anidulafungin treatment was associated with an incremental cost of $US231 (p = 0.98).
Anidulafungin as first-line treatment of C/IC appears to be of particular benefit to ICU patients, improving clinical outcomes and possibly decreasing costs, driven by reduced ICU and hospital stay, when compared with fluconazole. Anidulafungin also yielded significantly improved treatment outcomes in the general inpatient population, with total costs similar to fluconazole
Gender difference in the characteristics of and high-risk behaviours among non-injecting heterosexual methamphetamine users in Qingdao, Shandong Province, China
<p>Abstract</p> <p>Background</p> <p>Despite the increasing risk of HIV infections, few studies concerning the characteristics of non-injecting heterosexual methamphetamine (MA) users and related risk behaviours have been conducted in China.</p> <p>Methods</p> <p>Gender differences in socio-demographic characteristics, perception of MA and STD/HIV, MA use practices, and sexual behaviours related to MA use were examined among 398 non-injecting heterosexual MA users (288 males, 110 females).</p> <p>Results</p> <p>Male MA users were more likely to be married, local, and self-employed; female MA users were more likely to be young, single, engaged in commercial service or unemployed. Female MA users usually start MA use at an earlier age than males (24.3 vs. 31.3 years old), with shorter abuse durations (2.6 vs. 2.9 years), higher frequency of MA use (3.6 vs. 2.4 times per week), and higher likelihood of using MA with heterosexual partners (100% vs. 78.1%). More male MA users have had multiple sex partners (96.9% vs. 77.3%) and sex exchanges (72.9% vs. 46.4%). Among 277 males who had had sex with commercial sex workers (CSW), 69.4% never used condoms, and among 77 males who had had sex with multiple partners who are commercial sex workers and always or usually used condoms, 87.0% never changed condoms when changing partners.</p> <p>Conclusion</p> <p>There may be gender difference in the characteristics of high-risk behaviours among non-injecting heterosexual MA users. The findings suggest the integration of specific risk reduction strategies into intervention programs for non-injecting heterosexual MA user populations may significantly improve program goals.</p