57 research outputs found
Direct and indirect effects of the COVID-19 pandemic on mortality in Switzerland
The direct and indirect impact of the COVID-19 pandemic on population-level mortality is of concern to public health but challenging to quantify. Using data for 2011–2019, we applied Bayesian models to predict the expected number of deaths in Switzerland and compared them with laboratory-confirmed COVID-19 deaths from February 2020 to April 2022 (study period). We estimated that COVID-19-related mortality was underestimated by a factor of 0.72 (95% credible interval [CrI]: 0.46–0.78). After accounting for COVID-19 deaths, the observed mortality was −4% (95% CrI: −8 to 0) lower than expected. The deficit in mortality was concentrated in age groups 40–59 (−12%, 95%CrI: −19 to −5) and 60–69 (−8%, 95%CrI: −15 to −2). Although COVID-19 control measures may have negative effects, after subtracting COVID-19 deaths, there were fewer deaths in Switzerland during the pandemic than expected, suggesting that any negative effects of control measures were offset by the positive effects. These results have important implications for the ongoing debate about the appropriateness of COVID-19 control measures
Kinetic and Transport Equations for Localized Excitations in Sine-Gordon Model
We analyze the kinetic behavior of localized excitations - solitons,
breathers and phonons - in Sine-Gordon model. Collision integrals for all type
of localized excitation collision processes are constructed, and the kinetic
equations are derived. We analyze the kinetic behavior of localized excitations
- solitons, breathers and phonons - in Sine-Gordon model. Collision integrals
for all type of localized excitation collision processes are constructed, and
the kinetic equations are derived. We prove that the entropy production in the
system of localized excitations takes place only in the case of inhomogeneous
distribution of these excitations in real and phase spaces. We derive transport
equations for soliton and breather densities, temperatures and mean velocities
i.e. show that collisions of localized excitations lead to creation of
diffusion, thermoconductivity and intrinsic friction processes. The diffusion
coefficients for solitons and breathers, describing the diffusion processes in
real and phase spaces, are calculated. It is shown that diffusion processes in
real space are much faster than the diffusion processes in phase space.Comment: 23 pages, latex, no figure
Combination with tomatidine improves the potency of posaconazole against Trypanosoma cruzi
Azoles such as posaconazole (Posa) are highly potent against Trypanosoma cruzi. However, when tested in chronic Chagas disease patients, a high rate of relapse after Posa treatment was observed. It appears that inhibition of T. cruzi cytochrome CYP51, the target of azoles, does not deliver sterile cure in monotherapy. Looking for suitable combination partners of azoles, we have selected a set of inhibitors of sterol and sphingolipid biosynthetic enzymes. A small-scale phenotypic screening was conducted in vitro against the proliferative forms of T. cruzi, extracellular epimastigotes and intracellular amastigotes. Against the intracellular, clinically relevant forms, four out of 15 tested compounds presented higher or equal activity as benznidazole (Bz), with EC50 values </=2.2 muM. Ro48-8071, an inhibitor of lanosterol synthase (ERG7), and the steroidal alkaloid tomatidine (TH), an inhibitor of C-24 sterol methyltransferase (ERG6), exhibited the highest potency and selectivity indices (SI = 12 and 115, respectively). Both were directed to combinatory assays using fixed-ratio protocols with Posa, Bz, and fexinidazole. The combination of TH with Posa displayed a synergistic profile against amastigotes, with a mean SigmaFICI value of 0.2. In vivo assays using an acute mouse model of T. cruzi infection demonstrated lack of antiparasitic activity of TH alone in doses ranging from 0.5 to 5 mg/kg. As observed in vitro, the best combo proportion in vivo was the ratio 3 TH:1 Posa. The combination of Posa at 1.25 mpk plus TH at 3.75 mpk displayed suppression of peak parasitemia of 80% and a survival rate of 60% in the acute infection model, as compared to 20% survival for Posa at 1.25 mpk alone and 40% for Posa at 10 mpk alone. These initial results indicate a potential for the combination of posaconazole with tomatidine against T. cruzi
Polarons as Nucleation Droplets in Non-Degenerate Polymers
We present a study of the nucleation mechanism that allows the decay of the
metastable phase (trans-cisoid) to the stable phase
(cis-transoid) in quasi one-dimensional non-degenerate polymers within the
continuum electron-phonon model. The electron-phonon configurations that lead
to the decay, i.e. the critical droplets (or transition state), are identified
as polarons of the metastable phase. We obtain an estimate for the decay rate
via thermal activation within a range of parameters consistent with
experimental values for the gap of the cis-configuration. It is pointed out
that, upon doping, the activation barriers of the excited states are quite
smaller and the decay rate is greatly enhanced. Typical activation energies for
electron or hole polarons are eV and the typical size for a
critical droplet (polaron) is about . Decay via quantum nucleation is
also studied and it is found that the crossover temperature between quantum
nucleation and thermal activation is of order . Metastable
configurations of non-degenerate polymers may provide examples for mesoscopic
quantum tunneling.Comment: REVTEX 3.0, 28 PAGES, 3 FIGURES AVAILABLE UPON REQUEST, PITT 94-0
Photoinduced absorption and photoluminescence in poly(2,5-dimethoxy-p- phenylene vinylene)
We report a study of the photoexcited states in the conjugated polymer poly(2,5-dimethoxy-p-phenylene vinylene). Photoluminescence due to radiative recombination of singlet excitons is observed at energiesjust below the onset of the pi-pi* absorption band at 2.1 eV. Photoinduced absorption at 80 K shows bands peaking at 0.68, 1.35, and 1.80 eV. The features at 0.68 and 1.8 eV are associated with the same excited state which we propose is a doubly charged bipolaron, while the third at 1.35 eV is unrelated. We assign this 1.35-eV absorption to a triplet-triplet transition of a triplet exciton. The bipolarons are long lived with significant numbers surviving in excess of 100 ms at 80 K, and have a weak temperature dependence such that photoinduced absorption is readily detectable even at room temperature. The triplet exciton has a lifetime of order 2.5 ms at 80 K but this falls rapidly at higher temperature and the response is not detected at room temperature. We contrast these results with those obtained previously for the related poly(arylene vinylene) polymers poly(p-phenylene vinylene), and poly(2,5-thienylene vinylene) and for other conjugated polymers, and draw attention to the important role played in the photophysics of these materials by neutral excited states
Increased response to noradrenaline of isolated brown adipocytes from guinea pigs during cold-adaptation
8-10 años
Colección de 48 fichas con actividades destinadas a niños y niña de entre 8-10 años. Las preguntas que propone cada ficha se conciben para que el alumnado aprenda jugando. Cada pregunta va acompañada, en el reverso de la ficha, de la respuesta correspondiente. Las fichas se engloban en diferentes áreas: Lengua, Matemáticas, Sociales y Naturales.CataluñaES
10-12 años
Colección de 48 fichas con actividades destinadas a niños y niñas de entre 10-12 años. Las preguntas que propone cada ficha se conciben para que el alumnado aprenda jugando. Cada pregunta va acompañada, en el reverso de la ficha, de la respuesta correspondiente. Las fichas se engloban en diferentes áreas: Lengua, Matemáticas, Sociales y Naturales.CataluñaES
6-8 años
Colección de 48 fichas con actividades destinadas a niños y niñad de entre 6-8 años. Las preguntas se conciben para que el alumnado aprenda jugando. Cada pregunta va acompañada, en el reverso de la ficha, de la respuesta correspondiente. Las fichas se engloban en diferentes áreas: Lengua, Matemáticas, Sociales y Naturales.CataluñaES
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