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We study two-dimensional bosonic and fermionic lattice systems under nonequilibrium conditions corresponding to a sharp gradient of temperature imposed by two thermal baths. In particular, we consider a lattice model with broken time-reversal symmetry that exhibits both topologically trivial and nontrivial phases. Using a nonperturbative Green function approach, we characterize the nonequilibrium current distribution in different parameter regimes. For both bosonic and fermionic systems, we find chiral edge currents that are robust against coupling to reservoirs and to the presence of defects on the boundary or in the bulk. This robustness not only originates from topological effects at zero temperature but, remarkably, also persists as a result of dissipative symmetries in regimes where band topology plays no role. Chirality of the edge currents implies that energy locally flows against the temperature gradient without any external work input. In the fermionic case, there is also a regime with topologically protected boundary currents, which nonetheless do not circulate around all system edges.
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A general thermodynamic framework is presented for open quantum systems in fixed contact with a thermal reservoir. The first and second law are obtained for arbitrary system-reservoir coupling strengths, and including both factorized and correlated initial conditions. The thermodynamic properties are adapted to the generally strong coupling regime, approaching the ones defined for equilibrium, and their standard weak-coupling counterparts as appropriate limits. Moreover, they can be inferred from measurements involving only system observables. Finally, a thermodynamic signature of non-Markovianity is formulated in the form of a negative entropy production rate.
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We present a thermodynamic framework for the refined weak coupling limit. In this limit, the interaction between system and environment is weak, but not negligible. As a result, the system dynamics becomes non-Markovian breaking divisibility conditions. Nevertheless, we propose a derivation of the first and second law just in terms of the reduced system dynamics. To this end, we extend the refined weak coupling limit for allowing slowly-varying external drivings and reconsider the definition of internal energy due to the non-negligible interaction.
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We analyze the relation between completely positive (CP) divisibility and the lack of information backflow for an arbitrary-not necessarily invertible-dynamical map. It is well known that CP divisibility always implies a lack of information backflow. Moreover, these two notions are equivalent for invertible maps. In this Letter, it is shown that for a map which is not invertible the lack of information backflow always implies the existence of a completely positive propagator which, however, needs not be trace preserving. Interestingly, for a wide class of image nonincreasing dynamical maps, this propagator becomes trace preserving as well, and hence, the lack of information backflow implies CP divisibility. This result sheds new light into the structure of the time-local generators giving rise to CP-divisible evolutions. We show that if the map is not invertible then positivity of dissipation/decoherence rates is no longer necessary for CP divisibility.
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We present a comprehensive and up-to-date review of the concept of quantum non-Markovianity, a central theme in the theory of open quantum systems. We introduce the concept of a quantum Markovian process as a generalization of the classical definition of Markovianity via the so-called divisibility property and relate this notion to the intuitive idea that links non-Markovianity with the persistence of memory effects. A detailed comparison with other definitions presented in the literature is provided. We then discuss several existing proposals to quantify the degree of non-Markovianity of quantum dynamics and to witness non-Markovian behavior, the latter providing sufficient conditions to detect deviations from strict Markovianity. Finally, we conclude by enumerating some timely open problems in the field and provide an outlook on possible research directions.
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We analyze the steady state entanglement generated in a coherently coupled dimer system subject to dephasing noise as a function of the degree of Markovianity of the evolution. By keeping fixed the effective noise strength while varying the memory time of the environment, we demonstrate that non-Markovianity is an essential, quantifiable resource that may support the formation of steady state entanglement whereas purely Markovian dynamics governed by Lindblad master equations lead to separable steady states. This result illustrates possible mechanisms leading to long-lived entanglement in purely decohering, possibly local, environments. We present a feasible experimental demonstration of this noise assisted phenomenon using a system of trapped ions.
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We examine whether metrological resolution beyond coherent states is a nonclassical effect. We show that this is true for linear detection schemes but false for nonlinear schemes, and propose a very simple experimental setup to test it. We find a nonclassicality criterion derived from quantum Fisher information.
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We address the problem of quantifying the non-markovian character of quantum time evolutions of general systems in contact with an environment. We introduce two different measures of non-markovianity that exploit the specific traits of quantum correlations and are suitable for opposite experimental contexts. When complete tomographic knowledge about the evolution is available, our measure provides a necessary and sufficient condition to quantify strictly the non-markovianity. In the opposite case, when no information whatsoever is available, we propose a sufficient condition for non-markovianity. Remarkably, no optimization procedure underlies our derivation, which greatly enhances the practical relevance of the proposed criteria.
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The reaction of gem-dithiol compounds R 2C(SH) 2 (R = Bn (benzyl), (i) Pr; R 2 = -(CH 2) 4-) with dinuclear rhodium or iridium complexes containing basic ligands such as [M(mu-OH)(cod)] 2 and [M(mu-OMe)(cod)] 2, or the mononuclear [M(acac)(cod)] (M = Rh, Ir, cod = 1,5-cyclooctadiene) in the presence of a external base, afforded the dinuclear complexes [M 2(mu-S 2CR 2)(cod) 2] ( 1- 4). The monodeprotonation of 1,1-dimercaptocyclopentane gave the mononuclear complex [Rh(HS 2Cptn)(cod)] ( 5) that is a precursor for the dinuclear compound [Rh 2(mu-S 2Cptn)(cod) 2] ( 6). Carbonylation of the diolefin compounds gave the complexes [Rh 2(mu-S 2CR 2)(CO) 4] ( 7- 9), which reacted with P-donor ligands to stereoselectively produce the trans isomer of the disubstituted complexes [Rh 2(mu-S 2CR 2)(CO) 2(PR' 3) 2] (R' = Ph, Cy (cyclohexyl)) ( 10- 13) and [Rh 2(mu-S 2CBn 2)(CO) 2{P(OR') 3} 2] (R' = Me, Ph) ( 14- 15). The substitution process in [Rh 2(mu-S 2CBn 2)(CO) 4] ( 7) by P(OMe) 3 has been studied by spectroscopic means and the full series of substituted complexes [Rh 2(mu-S 2CBn 2)(CO) 4- n {P(OR) 3} n ] ( n = 1, 4) has been identified in solution. The cis complex [Rh 2(mu-S 2CBn 2)(CO) 2(mu-dppb)] ( 16) was obtained by reaction of 7 with the diphosphine dppb (1,4-bis(diphenylphosphino)butane). The molecular structures of the diolefinic dinuclear complexes [Rh 2(mu-S 2CR 2)(cod) 2] (R = Bn ( 1), (i) Pr ( 2); R 2 = -(CH 2) 4- ( 6)) and that of the cis complex 16 have been studied by X-ray diffraction.
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Irídio/química , Compostos Organometálicos/química , Ródio/química , Compostos de Sulfidrila/química , Alcenos/química , Ligantes , Estrutura Molecular , Difração de Raios XRESUMO
The study of non-equilibrium properties in topological systems is of practical and fundamental importance. Here, we analyze the stationary properties of a two-dimensional bosonic Hofstadter lattice coupled to two thermal baths in the quantum open-system formalism. Novel phenomena appear like chiral edge heat currents that are the out-of-equilibrium counterparts of the zero-temperature edge currents. They support a new concept of dissipative symmetry-protection, where a set of discrete symmetries protects topological heat currents, differing from the symmetry-protection devised in closed systems and zero-temperature. Remarkably, one of these currents flows opposite to the decreasing external temperature gradient. As the starting point, we consider the case of a single external reservoir already showing prominent results like thermal erasure effects and topological thermal currents. Our results are experimentally accessible with platforms like photonics systems and optical lattices.
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Introducción: al acudir a un centro hospitalario, los usuarios de servicios médicos tienen confianza en que su necesidad de salud será atendida y que al final el proceso sea solventado a cabalidad y eficazmente, es por ello importante conocer la satisfacción que tienen con los servicios. Objetivo: identificar el nivel de satisfacción con la atención médica de los usuarios atendidos en el servicio de emergencia. Métodos: estudio descriptivo de corte transversal en el servicio de emergencia del circuito de salud integral Augusto Egas de la ciudad de Santo Domingo de los Tsáchilas, Ecuador, durante el primer trimestre de 2015, en un universo de 382 pacientes a quienes se aplicó una encuesta validad para obtener la información, el análisis de la información, se realizó mediante el sistema SPSS, al hacer uso de la correlación bivariada de Kendall, los resultados se expresan en tablas de manera porcentual. Resultados: el personal de enfermería predominó como primer contacto con el usuario, brindó un trato agradable, de calidad y calidez, expresado en el 44 por ciento de la muestra, el sexo femenino prevaleció en los encuestados 66 por ciento; un 49 por ciento opinó que fue atendido en los primeros treinta minutos de su llegada al servicio, el 75 por ciento expresó haber recibido una atención médica y de enfermería satisfactoria. Conclusión: los pacientes que acuden al servicio de emergencia reciben una atención satisfactoria por parte del personal de salud(AU)
Introduction: Users of medical services to go to hospital they are confident that their health needs will be taken care of and ultimately the process is solved fully and effectively, it is therefore important to know the satisfaction with the services. Objective: Identify the level of satisfaction with the care of users treated in the emergency service. Methods: A descriptive cross-sectional study was conducted in the emergency circuit holistic health Augusto Egas of Santo Domingo de los Tsáchilas, Ecuador, during the first quarter of 2015, in a universe of 382 patients who applied a validate survey to obtain information, analysis of information, was performed using the SPSS system by making use of bivariate correlation Kendall, the results are expressed in percentage terms tables. Results: The nursing staff prevailed as the first contact with the user friendly service provided, quality and warmth expressed in 44 percent of the sample, the female respondents prevailed in 66 percent; 49 percent felt that it was handled in the first thirty minutes of their arrival at the service, 75 percent said they have received a satisfactory medical care and nursing. Conclusion: Patients who come to the emergency service receive satisfactory attention from health personnel(AU)
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Humanos , Feminino , Satisfação do Paciente , Cuidados Médicos/métodos , Assistência Ambulatorial/ética , Cuidados de Enfermagem/estatística & dados numéricos , Epidemiologia Descritiva , Estudos Transversais , Interpretação Estatística de DadosRESUMO
Introducción: el cáncer de pulmón es la neoplasia maligna más frecuente, y causante de un tercio de todas las muertes por cáncer, con un aumento significativo de su incidencia en los últimos años. Objetivo: identificar factores de riesgo asociados al cáncer de pulmón. Método: se realizó un estudio de casos y control en el Hospital Lucía Iñiguez Landín en el período entre julio de 2011 a enero de 2013. El universo estuvo constituido por 118 pacientes que ingresaron en Salas de Medicina que presentaban uno o varios factores de riesgo para esta enfermedad. De ellos, 59 pacientes con diagnósticos no relacionados con cáncer de pulmón fueron seleccionados como el grupo control y el grupo casos estuvo constituido por los 59 pacientes que ingresaron con este diagnóstico. Resultados: predominó en el grupo de casos el sexo masculino para 83,1%. Los fumadores representaron 71,2% del total del grupo casos. El hábito de fumar y la enfermedad pulmonar obstructiva crónica fueron los factores de riesgo de mayor importancia con una OR de 3,8 y 2,49, respectivamente. La exposición a sustancias cancerígenas y el alcoholismo no mostraron diferencias significativas entre ambos grupos. Conclusiones: el sexo masculino fue el más afectado por esta enfermedad. Los pacientes fumadores tuvieron 3,8 veces mayor riesgo de presentar cáncer de pulmón, que los no fumadores y los pacientes con enfermedad pulmonar obstructiva crónica presentaron 2,49 veces mayor probabilidad de desarrollar cáncer.
Introduction: the lung cancer is the most frequent malignant neoplasm and the cause of third of all deaths caused by the cancer, with a high increase of incidence in these last years. Objective: to determine the risk factors associated to lung cancer. Method: a cases and control study in Lucía Iñiguez Landín hospital from July 2011 to January 2013. The universe comprised 118 patients who were admitted in the medical - ward and presented one or some risks factors for this illness, 59 of these patients with diagnosis not related to lung cancer were selected as the control group and the case group was composed of 59 patients that were admitted with this diagnosis. Results: the male sex predominated in the case group the representing 83.1%. The smokers represented 71.2% of the cases group. The smoking and pulmonary obstructive chronic disease was the most important risk factors found with OR of 3.8 and 2.4 respectively. The cancerous substances exposure and the alcoholism did not show significant differences. Conclusion: the male sex was the most affected. The smokers had 3.8 more times of highest risk for lung cancer comparing with no smokers and those patients with obstructive pulmonary disease had 2.49 times of high probability for developing cancer.
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El carcinoma apocrino de glándula mamaria en cualquiera de sus presentaciones infiltrante o in situ constituye una rareza entre los tumores epiteliales de mama. Frecuencia en distintas casuísticas es variable, manteniendo criterios rigurosos cito-histológicos en la selectividad, donde el patrón dominante es sustitución total o casi total por epitelio de origen apocrino, se estima en 0,06 por ciento a 4 por ciento de todas las variantes histológicas. Presentamos el caso de una paciente 56 años con antecedente de tejido mamario axilar quien desarrolla carcinoma apocrino infiltrante, por sus características, agresividad local, sorprendente evolución, posterior al uso de quimioterapia neoadyuvante permitió exéresis total. Revisamos la literatura que permite conocer acerca de esta entidad infrecuente, la inmunohistoquímica puede ser de gran ayuda. La positividad a receptores androgénicos y negatividad a receptores de estrógeno y progesterona hacen pensar en inmunohistogénesis distinta, lo que pudiera proporcionar un enfoque terapéutico y pronósticos de estas variante histológicas del carcinoma mamario.
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Humanos , Feminino , Pessoa de Meia-Idade , Carcinoma , Anatomia , Mama/lesões , Patologia , Oncologia , VenezuelaRESUMO
Presentar la experiencia en la utilización del injerto autólogo del complejo areola-pezón en la cirugía reconstructiva de la mama. Se analizan retrospectivamente las pacientes con cáncer de mama ingresadas para tratamiento quirúrgico en el Servicio de Cirugía II, del Hospital Central de Maracay, entre abril 1986 y abril 2001. Sólo 20 pacientes de un total de 178 (11,2 por ciento) fueron sometidas a variados procedimientos de reconstrucción y donde el complejo areola pezón fue retirado y luego utilizado como injerto. Pasos de la técnica son presentados señalando aspectos relacionados con la selección. La edad promedio fue de 41 años (24-58 años). Utilizando distintas técnicas de reconstrucción mamaria, doce de ellos con cirugía radical preservadora de piel, cuatro con técnica periareolar y ocho con trazado de mastopexia. A todo este grupo se le colocó prótesis subpectoral; tres casos reconstruidas con TRAM Flap, las cinco restantes con latissimus dorsi con adición de prótesis en cuatro de ellos. Ocho casos (40 por ciento), venían de recibir quimioterapia de inducción. El injerto autólogo de areola y pezón fue utilizado en todos los casos. Hubo epidermolisis e infección con pérdida de injerto en un caso, en otro, pérdida parcial, requiriendo ser reconstruidos en forma diferida con injerto de piel de zona pigmentada. La enorme ventaja y el impacto psicológico de una reconstrucción inmediata es evidente. El complejo areola-pezón utilizado como injerto, ofrece una alternativa válida y segura, sin riesgo de recidiva dando un aspecto más natural