Inability of the entropy vector method to certify nonclassicality in linelike causal structures

Bell's theorem shows that our intuitive understanding of causation must be overturned in light of quantum correlations. Nevertheless, quantum mechanics does not permit signalling and hence a notion of cause remains. Understanding this notion is not only important at a fundamental level, but also for technological applications such as key distribution and randomness expansion. It has recently been shown that a useful way to decide which classical causal structures could give rise to a given set of correlations is to use entropy vectors. These are vectors whose components are the entropies of all subsets of the observed variables in the causal structure. The entropy vector method employs causal relationships among the variables to restrict the set of possible entropy vectors. Here, we consider whether the same approach can lead to useful certificates of non-classicality within a given causal structure. Surprisingly, we find that for a family of causal structures that include the usual bipartite Bell structure they do not. For all members of this family, no function of the entropies of the observed variables gives such a certificate, in spite of the existence of nonclassical correlations. It is therefore necessary to look beyond entropy vectors to understand cause from a quantum perspective.Comment: 5 pages + appendix, v2: added references, v3: new title, added journal referenc

Secondary user relations in emerging mobile computing environments

Mobile technologies are enabling access to information in diverse environ.ments, and are exposing a wider group of individuals to said technology. Therefore, this paper proposes that a wider view of user relations than is usually considered in information systems research is required. Specifically, we examine the potential effects of emerging mobile technologies on end-­‐user relations with a focus on the ‘secondary user’, those who are not intended to interact directly with the technology but are intended consumers of the technology’s output. For illustration, we draw on a study of a U.K. regional Fire and Rescue Service and deconstruct mobile technology use at Fire Service incidents. Our findings provide insights, which suggest that, because of the nature of mobile technologies and their context of use, secondary user relations in such emerging mobile environments are important and need further exploration

Axiomatic relation between thermodynamic and information-theoretic entropies

Thermodynamic entropy, as defined by Clausius, characterizes macroscopic observations of a system based on phenomenological quantities such as temperature and heat. In contrast, information-theoretic entropy, introduced by Shannon, is a measure of uncertainty. In this Letter, we connect these two notions of entropy, using an axiomatic framework for thermodynamics [Lieb, Yngvason, Proc. Roy. Soc.(2013)]. In particular, we obtain a direct relation between the Clausius entropy and the Shannon entropy, or its generalisation to quantum systems, the von Neumann entropy. More generally, we find that entropy measures relevant in non-equilibrium thermodynamics correspond to entropies used in one-shot information theory

Influencia de los cambios redox del receptor de rianodina (RyR2) sobre las arritmias cardíacas de reperfusión

El funcionamiento anormal del canal liberador de Ca2+, del retículo sarcoplasmático cardíaco o receptor de rianodina (RyR2), es reconocido como un factor importante en la patogénesis de las arritmias cardíacas. Cuando el miocardio es sometido a un período breve de isquemia seguido de reperfusión, se produce una alteración en la homeostasis del Ca2+ intracelular y un aumento del estrés oxidativo, que coinciden temporalmente con la aparición de arritmias.Facultad de Ciencias Médica

Influencia de los cambios redox del receptor de rianodina (RyR2) sobre las arritmias cardíacas de reperfusión

El funcionamiento anormal del canal liberador de Ca2+, del retículo sarcoplasmático cardíaco o receptor de rianodina (RyR2), es reconocido como un factor importante en la patogénesis de las arritmias cardíacas. Cuando el miocardio es sometido a un período breve de isquemia seguido de reperfusión, se produce una alteración en la homeostasis del Ca2+ intracelular y un aumento del estrés oxidativo, que coinciden temporalmente con la aparición de arritmias.Facultad de Ciencias Médica

Operando XANES study of simulated transient cycles on a Pd-only three-way catalyst

A model Pd-only three-way catalyst has been subjected to simulated driving conditions of natural gas and gasoline operation in an operando reactor cell for X-ray absorption spectroscopy that included alternated, but longer than real oscillations, rich and lean periods and a high temperature surge (850\u2013900 \ub0C). The X-ray absorption near edge structure (XANES) spectra indicated that metallic palladium is observed in the whole temperature range investigated (up to 900 \ub0C) and irrespective of the air/fuel ratio. In both natural gas and gasoline cycles, the XANES data show that the PdO reduced in the rich periods cannot be restored in the lean periods. With this background, activity for methane abatement in the high temperature regime is greatly affected by the oxidation state of palladium rather than by the change of air/fuel ratio. In the case of propene oxidation, while Pd also remains predominantly in the reduced state, activity is dictated by the oxygen concentration in the feedstock. Comparison between the two hydrocarbons demonstrates that the oxidation state of Pd may be responsible for observed methane emissions under realistic operating circumstances. Moreover, the experiments demonstrate that reduced Pd may be continuously present during operation in agreement with observations on real catalytic converters. Although this may be the average oxidation state of Pd, more advanced probes are certainly necessary to capture variations of oxidation state under the fast oscillatory conditions needed to imitate real operation

La proteína quinasa dependiente de Ca2+ y calmodulina (CaMKII): ¿es proarritmogénica en reperfusión?

La reperfusión del miocardio isquémico lo hace más propenso a la aparición de arritmias. Experimentos previos de nuestro laboratorio mostraron que al inicio de la reperfusión (R), momento en el que se detecta el mayor número de arritmias, aumenta la fosforilación dependiente de CaMKII del residuo PT17 de fosfolamban (PLN) (Vittone, 2002). El objetivo de este trabajo, fue evaluar la posibilidad de que la activación de CaMKII al inicio de la reperfusión sea un mecanismo proarritmogénico.Facultad de Ciencias Médica