Fundamental Finite Key Limits for One-Way Information Reconciliation in Quantum Key Distribution

The security of quantum key distribution protocols is guaranteed by the laws of quantum mechanics. However, a precise analysis of the security properties requires tools from both classical cryptography and information theory. Here, we employ recent results in non-asymptotic classical information theory to show that one-way information reconciliation imposes fundamental limitations on the amount of secret key that can be extracted in the finite key regime. In particular, we find that an often used approximation for the information leakage during information reconciliation is not generally valid. We propose an improved approximation that takes into account finite key effects and numerically test it against codes for two probability distributions, that we call binary-binary and binary-Gaussian, that typically appear in quantum key distribution protocols

Asymptotic dispersion for two-dimensional highly heterogeneous permeability fields under temporally fluctuating flow

International audienceTemporal fluctuations of water flux have been investigated as a mechanism that strongly enhances transverse dispersion in heterogeneous media. Unfortunately, most results have been obtained by linear stochastic theories on permeability fields of limited variability. Worse, results are inconsistent regarding the impact of fluctuations on longitudinal dispersion, which motivates our work to find the effect of temporal velocity fluctuations on macrodispersion. We perform numerical Monte Carlo simulations for highly variable permeability fields of up to 800 correlation lengths. We find that fluctuations longitudinal to the main flow direction hardly modify macrodispersion because they do not alter the flow lines. Fluctuations transverse to the main flow direction not only increase transverse dispersion, which is well known, but also reduce the longitudinal macrodispersion in a significant and consistent way, which contradicts previous findings. The reduction of the longitudinal dispersion is comparable to the increase of transverse dispersion. Most surprisingly, for high heterogeneity, temporal fluctuations cause total (longitudinal plus transverse) macrodispersion to drop with respect to the steady state one. Enhancement of the transverse macrodispersion comes from both the increase of the transverse velocity variability and Lagrangian correlation. Reduction of the longitudinal macrodispersion results from the reduction of the Lagrangian correlation of the longitudinal velocity. That is, temporal fluctuations reduce longitudinal spreading both by breaking the fastest velocity paths on the plume front and by letting solute bypass the low-permeability zones that tend to block or trap the solute in steady state flow conditions

Sistema de informação para a gestão de uma frota

Actualmente, vivemos num mundo complexo em que as organizações são entidades nas quais a Informação e os Sistemas de Informação são imprescindíveis para garantir a sua sobrevivência e para responder às suas necessidades. O desenvolvimento de um Sistema de Informação para a gestão de uma organização tem como papel principal o de apoiar a tomada de decisão, de forma a aumentar o sucesso e a competitividade da organização. Este artigo apresenta a tecnologia associada a um sistema de apoio à decisão que permite efectuar a gestão de uma frota, dentro de uma organização. Para efectuar a gestão de uma frota é necessário analisar e controlar os custos de utilização, manutenção e reparação de viaturas

Sequential curing of thiol-acetoacetate-acrylate thermosets by latent Michael addition reactions

Thiol-acetoacetate-acrylate ternary dual-curing thermosets were prepared by a sequential process consisting of thiol-Michael addition to acrylates at room temperature followed by Michael addition of acetoacetates to acrylates at moderately elevated temperature. The curing sequence can be controlled with the help of the different acidities of the protons on thiol and acetoacetate groups, the favorable pKa of the base used as catalyst and the self-limiting character of Michael additions. The latency of the curing steps can be regulated by selection of the right catalysts, temperature and curing conditions. The properties of the intermediate and final materials can be tuned by changing the structure of the monomers and the contribution of both Michael addition reactions.Postprint (author's final draft

Colangiopancreatografía retrógrada endoscópica en pancreatitis biliar aguda. ¿Herramienta diagnóstica o terapéutica? Revisión sistemática de la literatura 2008-2013

La pancreatitis aguda tiene como causa frecuente las enfermedades del tracto biliar, por lo que muchas guías de manejo recomiendan que una terapéutica con una colangiopancreatografía retrógrada endoscópica (CPRE) urgente sea realizada dentro de las primeras 72 horas de admisión de todos los pacientes con probabilidad de tener pancreatitis biliar aguda severa, con o sin colangitis presente. El objetivo de esta publicación es la revisión sistemática de la literatura de los a˜nos 2008 al 2013. Método: Búsqueda de artículos en las bases de datos de PUBMED y The Cochrane Library utilizando como estrategia las palabras ‘‘Pancreatitis Biliar Aguda’’, ‘‘Pancreatitis Aguda’’ y ‘‘Colangiopancreatografía Retrograda Endoscópica’’; se aplicó el uso de los filtros ‘‘meta-análisis’’, ‘‘ensayos clínicos controlados’’, ‘‘revisiones sistemáticas’’, ‘‘estudios multicéntricos’’, ‘‘revisiones de casos’’ y ‘‘artículo de revisión’’. Resultados y conclusiones: Se revisaron 74 artículos en las bases de datos: 8 meta análisis (5.92%), 12 revisiones sistemáticas (8.88%), 10 estudios multicéntricos (7.4%), 18 ensayos clínicos (13.32%), y artículos de revisión o reportes de casos (64.48%). Dentro de los artículos revisados se encontraron 5 meta análisis, 6 revisiones sistemáticas, 5 estudios multicéntricos y 10 ensayos clínicos que cumplieron con los criterios de inclusión, clasificándolos por nivel de ∗ Autor para correspondencia

GAEC workshop 2012 technical report

The report describes the main technical findings and results of the Good Agricultural and Environmental Condition (GAEC) workshop 2012 organised by the Joint Research Centre (JRC). The workshop was held at the JRC in Ispra from 8th-10th October 2012. 110 delegates attended the workshop representing 24 European Union Member States, two candidate countries (Croatia and Iceland) and Commission services. The workshop focussed on implementation and control issues related to the identification and measure of landscape features and buffer strips, as well as on scientific references for definition and mapping of soil related issues (e. g. soil erosion or soil organic matter). Participants also showed much interest on technical aspects related to the implementation of the future CAP with particular reference to landscape features in the framework of the so-called Ecological Focus Area. The workshop allows setting up and fine-tuning future main JRC activities taking into account DG AGRI and Member States inputs.JRC.H.4-Monitoring Agricultural Resource

Beyond First/Last Mile Active Transportation - BikeShare@UH

Bike sharing is a new green transportation solution that has been developed and adopted at various cities around the world. In this paper, we present the process and results of the design and prototypes that a group of undergraduate students developed for a BikeShare@UH program during Summer 2017. After presenting the detailed results of four project teams focusing on customer discovery, bike share station (BSS) location identification, cloud-based mobile computing platform for user engagement and bike share program operation and management, smart lock, and alternative energy source based on PV panel. With the phase one implementation at the University planned in Spring 2018, we anticipate gathering real time data and feedback to improve the system.Cockrell School of Engineerin

Time evolution of mixing in heterogeneous porous media

International audienceMixing in heterogeneous media results from the competition between velocity fluctuations and local scale diffusion. Velocity fluctuations create a potential for mixing by generating disorder and large interfacial areas between resident and invading waters. Local scale diffusion smoothes out the disorder while transforming this potential into effective mixing. The effective mixing state is quantified by the integral of concentration squared over the spatial domain. Because it emerges from dispersion, the potential mixing is defined as the mixing state of a Gaussian plume that has the same longitudinal dispersion as the real plume. The difference between effective and potential mixing normalized by the latter traduces the lag of diffusion to homogenize the concentration structure generated by the dispersion processes. This new decomposition of effective mixing into potential mixing and departure rate makes a full use of dispersion for quantifying mixing and restricts the analysis of mixing to . For cases where the mean concentration can be assumed Gaussian, we use the concentration variance equation of Kapoor and Gelhar (1994) to show that depends solely on the macrodispersion coefficient (spreading rate) and the recently developed mixing scale defined as the smallest scale over which concentration can be considered uniform, and which quantifies the internal plume disorder. We use numerical simulations to show that turns out to follow a simple scaling form that depends on neither the heterogeneity level or the Peclet number. A very similar scaling form is recovered for Taylor dispersion. Both derivations of reinforce its relevance to characterize mixing. This generic characterization of mixing can offer new ways to set up transport equations that honor not only advection and spreading but also mixing