Stochastic thermodynamics of hidden pumps

We show that a reversible pumping mechanism operating between two states of a kinetic network can give rise to Poisson transitions between these two states. An external observer, for whom the pumping mechanism is not accessible, will observe a Markov chain satisfying local detailed balance with an emerging effective force induced by the hidden pump. Due to the reversibility of the pump, the actual entropy production turns out to be lower than the coarse grained entropy production estimated from the flows and affinities of the resulting Markov chain. Moreover, in presence of a large time scale separation between the fast pumping dynamics and the slow network dynamics, a finite current with zero dissipation may be produced. We make use of these general results to build a synthetase-like kinetic scheme able to reversibly produce high free energy molecules at a finite rate and a rotatory motor achieving 100\% efficiency at finite speed.Comment: 8 pages, 3 figures, v1: First version, v2: Major changes, new applications and new results (pumping can always be performed reversibly), v3 version accepted in Phys. Rev.

Measuring gambling: Prevalence of at risk and problematic gambling in Chile 2015-2018.

This study reports the prevalence of problematic gambling in Santiago de Chile for the period 2015-2018. Two household-based surveys were implemented in the metropolitan area of Santiago de Chile in 2015 and 2018 in order to assess changes on the prevalence, characteristics and severity of gambling (n=1030 each; SE=2,2% for a CI=95%). Severity of gambling was measured using the NODS scale. Results show that during the analysed period the percentage of at-risk players has increased, passing from 14,3% to 16,1%, among them, we identified a decrease in the prevalence of pathological gamblers, passing from 2,4% to 1,4%. We also identify a change in the type of pathological gambler: while in 2015, the main pathological gamblers were women, in 2018, most pathological players were men. In both years, most pathological gamblers came from lower social strata. In both years, the most played games were bingo and lottery, scratch cards and nonregulated slot machines. In 2018, most people declared to play solo, while in 2018, most people declare to play with friends and family. There are significant differences between at risk and not at-risk gamblers in satisfaction with life and other psychosocial indicators

Three-Dimensional Spectral-Domain Optical Coherence Tomography Data Analysis for Glaucoma Detection

Purpose: To develop a new three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) data analysis method using a machine learning technique based on variable-size super pixel segmentation that efficiently utilizes full 3D dataset to improve the discrimination between early glaucomatous and healthy eyes. Methods: 192 eyes of 96 subjects (44 healthy, 59 glaucoma suspect and 89 glaucomatous eyes) were scanned with SD-OCT. Each SD-OCT cube dataset was first converted into 2D feature map based on retinal nerve fiber layer (RNFL) segmentation and then divided into various number of super pixels. Unlike the conventional super pixel having a fixed number of points, this newly developed variable-size super pixel is defined as a cluster of homogeneous adjacent pixels with variable size, shape and number. Features of super pixel map were extracted and used as inputs to machine classifier (LogitBoost adaptive boosting) to automatically identify diseased eyes. For discriminating performance assessment, area under the curve (AUC) of the receiver operating characteristics of the machine classifier outputs were compared with the conventional circumpapillary RNFL (cpRNFL) thickness measurements. Results: The super pixel analysis showed statistically significantly higher AUC than the cpRNFL (0.855 vs. 0.707, respectively, p = 0.031, Jackknife test) when glaucoma suspects were discriminated from healthy, while no significant difference was found when confirmed glaucoma eyes were discriminated from healthy eyes. Conclusions: A novel 3D OCT analysis technique performed at least as well as the cpRNFL in glaucoma discrimination and even better at glaucoma suspect discrimination. This new method has the potential to improve early detection of glaucomatous damage. © 2013 Xu et al

Presence in a Distributed Virtual Environment

Collaborative Virtual Environments (CVEs) involve the use of a distributed architecture, and advanced interactive user interfaces to create a ‘shared’ sense of space where users located in different physical locations can interact. An important objective is to provide users with an illusion that the machine mediated experience is not mediated. The extent of this illusion is measured by the sense of ‘presence’ experienced. We explore ‘shared presence’ in a Cooperative Virtual Environment, that is providing the participants with a sense of presence of others in the environment, thus having a feeling that they are directly cooperating with real people. We describe our prototype system for a ‘non-immersive’ distributed virtual environment. We provide preliminary results on factors which increase the sense of ‘shared presence’ in a virtual environment. These include the use of avatars to represent the participants, providing simple communication and interaction with the environment. Our prototype has served as a good basis for our future work towards shared presence by highlighting areas that require attention, (such as providing communicative behaviour to avatars) and indicating good prospects such as the importance of how one represents the avatars

Presence and Co-Presence in Collaborative Virtual Environments

Collaborative Virtual Environments (CVEs) involve the use of a distributed architecture, and advanced interactive user interfaces to create a ’shared’ sense of space where users located in different physical locations can interact. In this paper, we describe two experimental designs which use subjective evaluation methods to asses personal presence and co-presence in a CVE. Personal presence is having a feeling of “being there” in the CVE yourself. Co-presence is having a feeling that one is in the same place as the other participants, and that one is collaborating with real people. The first experiment investigates the effects of avatar appearance and functionality (gestures and facial expressions) on presence and co-presence in a CVE. The second experiment investigates the effects of small group collaboration on co-presence in a CVE

A Human Development Framework for CO2 Reductions

Although developing countries are called to participate in CO2 emission reduction efforts to avoid dangerous climate change, the implications of proposed reduction schemes in human development standards of developing countries remain a matter of debate. We show the existence of a positive and time-dependent correlation between the Human Development Index (HDI) and per capita CO2 emissions from fossil fuel combustion. Employing this empirical relation, extrapolating the HDI, and using three population scenarios, the cumulative CO2 emissions necessary for developing countries to achieve particular HDI thresholds are assessed following a Development As Usual approach (DAU). If current demographic and development trends are maintained, we estimate that by 2050 around 85% of the world's population will live in countries with high HDI (above 0.8). In particular, 300Gt of cumulative CO2 emissions between 2000 and 2050 are estimated to be necessary for the development of 104 developing countries in the year 2000. This value represents between 20% to 30% of previously calculated CO2 budgets limiting global warming to 2{\deg}C. These constraints and results are incorporated into a CO2 reduction framework involving four domains of climate action for individual countries. The framework reserves a fair emission path for developing countries to proceed with their development by indexing country-dependent reduction rates proportional to the HDI in order to preserve the 2{\deg}C target after a particular development threshold is reached. Under this approach, global cumulative emissions by 2050 are estimated to range from 850 up to 1100Gt of CO2. These values are within the uncertainty range of emissions to limit global temperatures to 2{\deg}C.Comment: 14 pages, 7 figures, 1 tabl

Influence of shaking and viable cell numbers on microbial conjugated linoleic acid (CLA) production

info:eu-repo/semantics/publishedVersio

Thermodynamics of Higher Spin Black Holes in AdS3_3

We discuss the thermodynamics of recently constructed three-dimensional higher spin black holes in SL(N,R)\times SL(N,R) Chern-Simons theory with generalized asymptotically-anti-de Sitter boundary conditions. From a holographic perspective, these bulk theories are dual to two-dimensional CFTs with W_N symmetry algebras, and the black hole solutions are dual to thermal states with higher spin chemical potentials and charges turned on. Because the notion of horizon area is not gauge-invariant in the higher spin theory, the traditional approaches to the computation of black hole entropy must be reconsidered. One possibility, explored in the recent literature, involves demanding the existence of a partition function in the CFT, and consistency with the first law of thermodynamics. This approach is not free from ambiguities, however, and in particular different definitions of energy result in different expressions for the entropy. In the present work we show that there are natural definitions of the thermodynamically conjugate variables that follow from careful examination of the variational principle, and moreover agree with those obtained via canonical methods. Building on this intuition, we derive general expressions for the higher spin black hole entropy and free energy which are written entirely in terms of the Chern-Simons connections, and are valid for both static and rotating solutions. We compare our results to other proposals in the literature, and provide a new and efficient way to determine the generalization of the Cardy formula to a situation with higher spin charges.Comment: 30 pages, PDFLaTeX; v2: typos corrected, explicit expressions for the free energy adde