625 research outputs found
Percepción de calidad de vida y bienestar de las personas mayores del programa universitario para mayores en la Universidad de Barcelona
Podeu consultar la Vuitena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/66524Una de las principales cuestiones planteadas con el progresivo envejecimiento de la población es si el aumento de la esperanza de vida estará acompanhado con buen estado de salud y perspectivas para un envejecimiento activo. Por esta razón, investigaciones sobre las condiciones que contribuyen para una buen calidad de vida en la vejez revistense de gran importancia científica y social. En esta perspectiva, el estudio objetiva identificar los significados de calidad de vida relacionados con las actividades desarrolladas por la Universidad de la Experiencia, de la Universidad de Barcelona, en la perspectiva de sus participantes de mayor edad. Este es un estudio descriptivo y exploratorio, con enfoque teórico-metodológico cualitativo, realizado con 22 personas mayores inscritos en la Universidad de la Experiencia de la UB, en el curso acadêmico 2014-2015..
Markovian master equations for quantum thermal machines: local vs global approach
The study of quantum thermal machines, and more generally of open quantum
systems, often relies on master equations. Two approaches are mainly followed.
On the one hand, there is the widely used, but often criticized, local
approach, where machine sub-systems locally couple to thermal baths. On the
other hand, in the more established global approach, thermal baths couple to
global degrees of freedom of the machine. There has been debate as to which of
these two conceptually different approaches should be used in situations out of
thermal equilibrium. Here we compare the local and global approaches against an
exact solution for a particular class of thermal machines. We consider
thermodynamically relevant observables, such as heat currents, as well as the
quantum state of the machine. Our results show that the use of a local master
equation is generally well justified. In particular, for weak inter-system
coupling, the local approach agrees with the exact solution, whereas the global
approach fails for non-equilibrium situations. For intermediate coupling, the
local and the global approach both agree with the exact solution and for strong
coupling, the global approach is preferable. These results are backed by
detailed derivations of the regimes of validity for the respective approaches.Comment: Published version. See also the related work by J. Onam Gonzalez et
al. arXiv:1707.0922
Effects of tributyltin chloride on cybrids with or without an ATP synthase pathologic mutation
Background: The oxidative phosphorylation system (OXPHOS) includes nuclear chromosome (nDNA)– and mitochondrial DNA (mtDNA)–encoded polypeptides. Many rare OXPHOS disorders, such as striatal necrosis syndromes, are caused by genetic mutations. Despite important advances in sequencing procedures, causative mutations remain undetected in some patients. It is possible that etiologic factors, such as environmental toxins, are the cause of these cases. Indeed, the inhibition of a particular enzyme by a poison could imitate the biochemical effects of pathological mutations in that enzyme. Moreover, environmental factors can modify the penetrance or expressivity of pathological mutations. Objectives: We studied the interaction between mitochondrially encoded ATP synthase 6 (p.MT-ATP6) subunit and an environmental exposure that may contribute phenotypic differences between healthy individuals and patients suffering from striatal necrosis syndromes or other mitochondriopathies. Methods: We analyzed the effects of the ATP synthase inhibitor tributyltin chloride (TBTC), a widely distributed environmental factor that contaminates human food and water, on transmitochondrial cell lines with or without an ATP synthase mutation that causes striatal necrosis syndrome. Doses were selected based on TBTC concentrations previously reported in human whole blood samples. Results: TBTC modified the phenotypic effects caused by a pathological mtDNA mutation. Interestingly, wild-type cells treated with this xenobiotic showed similar bioenergetics when compared with the untreated mutated cells. Conclusions: In addition to the known genetic causes, our findings suggest that environmental exposure to TBTC might contribute to the etiology of striatal necrosis syndromes
Intrinsic Localized Modes Observed in the High Temperature Vibrational Spectrum of NaI
Inelastic neutron measurements of the high-temperature lattice excitations in
NaI show that in thermal equilibrium at 555 K an intrinsic mode, localized in
three dimensions, occurs at a single frequency near the center of the spectral
phonon gap, polarized along [111]. At higher temperatures the intrinsic
localized mode gains intensity. Higher energy inelastic neutron and x-ray
scattering measurements on a room-temperature NaI crystal indicate that the
creation energy of the ground state of the intrinsic localized mode is 299 meV.Comment: 17 pages, 5 figures Revised version; final versio
Magnetism and unconventional superconductivity in CeMIn heavy-fermion crystals
We review magnetic, superconducting and non-Fermi-liquid properties of the
structurally layered heavy-fermion compounds CeMIn (M=Co, Rh,
Ir). These properties suggest d-wave superconductivity and proximity to an
antiferromagetic quantum-critical point.Comment: submitted 23rd International Conference on Low Temperature Physics
(LT-23), Aug. 200
Novel Coexistence of Superconductivity with Two Distinct Magnetic Orders
The heavy fermion Ce(Rh,Ir)In5 system exhibits properties that range from an
incommensurate antiferromagnet on the Rh-rich end to an exotic superconductor
on the Ir-rich end of the phase diagram. At intermediate composition where
antiferromagnetism coexists with superconductivity, two types of magnetic order
are observed: the incommensurate one of CeRhIn5 and a new, commensurate
antiferromagnetism that orders separately. The coexistence of f-electron
superconductivity with two distinct f-electron magnetic orders is unique among
unconventional superconductors, adding a new variety to the usual coexistence
found in magnetic superconductors.Comment: 3 figures, 4 page
Markovian master equations for quantum thermal machines: local versus global approach
The study of quantum thermal machines, and more generally of open quantum systems, often relies on master equations. Two approaches are mainly followed. On the one hand, there is the widely used, but often criticized, local approach, where machine sub-systems locally couple to thermal baths. On the other hand, in the more established global approach, thermal baths couple to global degrees of freedom of the machine. There has been debate as to which of these two conceptually different approaches should be used in situations out of thermal equilibrium. Here we compare the local and global approaches against an exact solution for a particular class of thermal machines. We consider thermodynamically relevant observables, such as heat currents, as well as the quantum state of the machine. Our results show that the use of a local master equation is generally well justified. In particular, for weak inter-system coupling, the local approach agrees with the exact solution, whereas the global approach fails for non-equilibrium situations. For intermediate coupling, the local and the global approach both agree with the exact solution and for strong coupling, the global approach is preferable. These results are backed by detailed derivations of the regimes of validity for the respective approaches
Novel stripe-type charge ordering in the metallic A-type antiferromagnet Pr{0.5}Sr{0.5}MnO{3}
We demonstrate that an A-type antiferromagnetic (AFM) state of
Pr{0.5}Sr{0.5}MnO{3} exhibits a novel charge ordering which governs the
transport property. This charge ordering is stripe-like, being characterized by
a wave vector q ~ (0,0,0.3) with very anisotropic correlation parallel and
perpendicular to the stripe direction. This charge ordering is specific to the
manganites with relatively wide one-electron band width (W) which often exhibit
a metallic A-type AFM state, and should be strictly distinguished from the
CE-type checkerboard-like charge ordering which is commonly observed in
manganites with narrower W such as La{1-x}Ca{x}MnO{3} and Pr{1-x}Ca{x}MnO{3}.Comment: REVTeX4, 5 pages, 4 figure
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