Entanglement dynamics in open two-qubit systems via diffusive quantum trajectories

We use quantum diffusive trajectories to prove that the time evolution of two-qubit entanglement under spontaneous emission can be fully characterized by optimal continuous monitoring. We analytically determine this optimal unraveling and derive a deterministic evolution equation for the system's concurrence. Furthermore, we propose an experiment to monitor the entanglement dynamics in bipartite two-level systems and to determine the disentanglement time from a single trajectory.Comment: 4 pages, 2 figures, changed title, abstract and fig. 2, corrected typo

Characterisation of ozone levels and associated NMVOC emissions in Spain:

In Europe, for the last decades, multiple efforts have been made to regulate and reduce air pollution. Despite the overall reduction trends in emissions, air quality remains poor in many areas, where 99% of the urban population is exposed to tropospheric ozone (referred to as O3 from here on) concentrations above the World Health Organization Air Quality Guideline value [1]. O3 is a secondary atmospheric pollutant with complex mechanisms of formation and reaction processes, transport, and deposition. The nonlinear nature of its production is one of the main challenges in controlling ozone levels [2]. Spain shows several areas with O3 problems. Regarding the target value of O3 for health protection, out of the 127 areas where it was evaluated in 2019, 34 of them show values above the target value, 81 values between the target value and the long-term target value, and the remaining 12 are below the long-term objective. These results have not substantially improved since 2011 and are constant since 2016 [3]. The Spanish Ministry is currently designing a strategy to tackle the O3 problem in Spain. In this context, air quality modelling systems become an important complementary tool on which to quantify and evaluate the impact of such air quality plans. Two major directly emitted precursors drive O3 formation: nitrogen oxides (NOx) (which includes both nitrogen monoxide, NO, and nitrogen dioxide, NO2) and non-methane volatile organic compounds (NMVOC), so in order to assess O3, a correct characterization of its precursors is required. This work focuses on producing a speciated NMVOC inventory for anthropogenic emissions in Spain to support more effective control strategies. The type of NMVOCs emitted varies widely from one source to another, differing substantially by, e.g. fuel, technology, and others. The significant differences between NMVOC species lead to differences in atmospheric chemical reactivity and result in differences in their influence on the formation of ozone. Therefore, speciated NMVOCs emissions and the estimation of ozone formation potential (OFP) are essential to the reactivity-based control approach

Local traffic contribution to black carbon horizontal and vertical profiles in compact urban areas

Urban air pollution is characterized by strong spatial gradients produced by the presence of heavily trafficked streets. Given the negative health effects of air pollution, decision makers are implementing policies to reduce air pollution by modifying traffic flows near activity patterns of vulnerable populations. However, to our knowledge, there is quite a lack of appropriate decision tools to support such modifications at neighborhood to street levels. Measured horizontal and vertical distributions of traffic air pollutants can help understanding the variation of concentrations at increasing distances from emitting roads. Yet, models are still necessary to estimate the contribution of local traffic to measured concentrations. The main objective of this work is to investigate the contribution of local traffic to black carbon horizontal and vertical profiles based on measurements and model simulations. We will discuss the degree of influence of the different streets on black carbon measured profiles in Barcelona

Probabilistic model-checking of collaborative robots: a human injury assessment in agricultural applications

Current technology has made it possible to automate a number of agricultural processes that were traditionally carried out by humans and now can be entirely performed by robotic platforms. However, there are certain tasks like soft fruit harvesting, where human skills are still required. In this case, the robot's job is to cooperate/collaborate with human workers to alleviate their physical workload and improve the harvesting efficiency. To accomplish that in a safe and reliable way, the robot should incorporate a safety system whose main goal is to reduce the risk of harming human co-workers during close human-robot interaction (HRI). In this context, this paper presents a theoretical study, addressing the safety risks of using collaborative robots in agricultural scenarios, especially in HRI situations when the robot's safety system is not completely reliable and a component may fail. The agricultural scenarios discussed in this paper include automatic harvesting, logistics operations, crop monitoring, and plant treatment using UV-C light. A human injury assessment is conducted based on converting the HRI in each agricultural scenario into a formal mathematical representation. This representation is later implemented in a probabilistic model-checking tool. We then use this tool to perform a sensitivity analysis that allows us to determine the probability that a human may get injured according to the occurrence of failures in the robot's safety system. The probabilistic modeling methodology presented in this work can be used by safety engineers as a guideline to construct their own HRI models and then use the results of the model-checking to enhance the safety and reliability of their robot's safety system architectures

An integrated model system tool to evaluate the impact of urban mobility policies on air pollution: Barcelona case study

Air pollution remains as a key unresolved problem in many urban areas. Cities with such problem are gradually implementing Traffic Management Strategies (TMS) to reduce the total kilometers travelled by vehicles and subsequently decrease emissions. However, a prior evaluation of such TMS is needed if the target goals want to be achieved. In this sense, the combination of traffic simulation with emissions and air quality models can be of great use to assess the potential impacts of such policies. This study presents an integrated modelling system tool for Barcelona that allows to estimate the changes induced by the implementation of TMS on traffic activity, emissions and air quality levels at a very spatial (street level) and temporal (hourly level) resolution

Testing simple models for street wind conditions in Barcelona

Street wind speed and direction drive models to estimate air quality levels at street scale. In this study, simple models are combined with a mesoscale meteorological model to provide wind conditions at street level. Then, wind speed and direction are evaluated using observations collected during an experimental campaign in April 2013 at street level in Barcelona, Spain. Overall, models considering street geometry give better estimates for both wind speed and direction than those assuming homogeneous terrain. For light winds, models tend to produce a large amount of error estimating wind direction

Inventario de emisiones atmosféricas de puertos y aeropuertos de España para el año 2008

El principal objetivo del presente PFC consiste en la elaboración de un inventario de emisiones atmosféricas de puertos y aeropuertos de España, para el año 2008. El inventario se centra en las emisiones ocasionadas por las operaciones de buques y aeronaves dentro de los polígonos portuarios y aeroportuarios, sin tener en cuenta otros focos de emisión que actúa en ellos. Para su realización se recurre a distintas guías metodológicas diseñadas para la elaboración de inventarios de emisiones, así como a datos y estadísticas referentes a tráficos y características infraestructurales de los distintos puertos y aeropuertos. Como resultados se obtienen las emisiones anuales de los contaminantes primarios NOx (óxidos de nitrógeno), CO (monóxido de carbono), NMCOV (compuestos orgánicos volátiles distintos al metano), SO2 (dióxido de azufre), PST (partículas en suspensión totales), PM10 (material particulado de diámetro <10um), PM2,5 (material particulado de diámetro <2.5um); y de los Gases de Efecto Invernadero (GEIs) CO2 (dióxido de carbono) y CH4 (metano), derivadas del tráfico aéreo y marítimo en cada uno de los puertos y aeropuertos gestionados por Puertos del Estado y AENA (Aeropuertos Españoles y Navegación Aérea), respectivamente. Estos valores obtenidos son comparados, a nivel de Comunidades Autónomas (CCAA), con los resultados reportados por el Inventario Nacional de Emisiones (INE), elaborado por el Ministerio de Medio Ambiente Rural y Marino (MARM), lo cual permite validar los datos y metodologías aplicados. Analizando globalmente los resultados, se obtiene que las emisiones derivadas del tráfico aéreo son superiores en los NMCOV, CO, CO2 y CH4, mientras que las operaciones de buques dentro de puertos producen mayores emisiones de NOx, SO2, PM10 y PM2.5. A nivel de infraestructuras, el aeropuerto de Madrid-Barajas es el que presenta una mayor cantidad de contaminantes primarios y GEIs emitidos. En cuanto a puertos, el de Barcelona es el que encabeza la lista de emisiones de contaminantes primarios, mientras que Bahía de Algeciras muestra la mayor cantidad de GEIs

Català a Twitter, l’àgora de la llengua

En aquest article ens fixarem en la divulgació de la llengua catalana en una xarxa social molt usada entre els catalanoparlants, Twitter, que avui dia es considera una eina difusora equiparable als mitjans de comunicació, atès que molts dels usuaris manifesten que també la fan servir per informar-se. Ens centrarem en els comptes més seguits que difonen continguts lingüístics per mirar de calibrar quin impacte tenen entre la part de la comunitat lingüística que fa servir les xarxes socials. D’una banda, farem una classificació dels diferents comptes més seguits segons si són institucions, comptes impersonals de divulgació o persones independents, i seleccionarem els més seguits de cada classe. Tindrem en compte els que tracten sobre la normativa, l’adequació, la genuïnitat, els barbarismes, la paremiologia, els dialectalismes, etc. Es tracta de comptes com ara el de l’Optimot, l’IEC, però també de Josep Maria Virgili, El català com cal, etc. D’una altra banda, de cada compte determinarem quants seguidors tenen, quants continguts han estat publicats fins al moment, si hi ha interaccions amb la resta d’usuaris i des de quan tenen activitat. També establirem quina mena d’activitat tenen, amb quina periodicitat publiquen i de quina manera presenten la informació.In this article we will talk about the dissemination of the Catalan language in a social network widely used among Catalan speakers, Twitter, which nowadays has a similar function to the media, as many users say they also use it to get informed. We will focus on the most followed accounts that disseminate language content to have an idea of the impact they have in the part of the language community that uses social media. On the one hand, we will classify the most followed accounts according to whether they are institutions, anonymous accounts with linguistic content or independent people, and we will select the most followed one in each class. We will consider those that deal with norms, adequacy, genuineness, barbarisms, idioms, dialectalisms, and so on. These are accounts such as that of Optimot and IEC, but also that of Josep Maria Virgili, El català com cal, etc. On the other hand, we will determine how many followers each account has, how much content they have published so far, whether they have interactions with other users and since when they have activity. We will also establish what kind of activity they have, how often they publish, and how they present the information

Inventario de emisiones atmosféricas de puertos y aeropuertos de España para el año 2008

El principal objetivo del presente PFC consiste en la elaboración de un inventario de emisiones atmosféricas de puertos y aeropuertos de España, para el año 2008. El inventario se centra en las emisiones ocasionadas por las operaciones de buques y aeronaves dentro de los polígonos portuarios y aeroportuarios, sin tener en cuenta otros focos de emisión que actúa en ellos. Para su realización se recurre a distintas guías metodológicas diseñadas para la elaboración de inventarios de emisiones, así como a datos y estadísticas referentes a tráficos y características infraestructurales de los distintos puertos y aeropuertos. Como resultados se obtienen las emisiones anuales de los contaminantes primarios NOx (óxidos de nitrógeno), CO (monóxido de carbono), NMCOV (compuestos orgánicos volátiles distintos al metano), SO2 (dióxido de azufre), PST (partículas en suspensión totales), PM10 (material particulado de diámetro <10um), PM2,5 (material particulado de diámetro <2.5um); y de los Gases de Efecto Invernadero (GEIs) CO2 (dióxido de carbono) y CH4 (metano), derivadas del tráfico aéreo y marítimo en cada uno de los puertos y aeropuertos gestionados por Puertos del Estado y AENA (Aeropuertos Españoles y Navegación Aérea), respectivamente. Estos valores obtenidos son comparados, a nivel de Comunidades Autónomas (CCAA), con los resultados reportados por el Inventario Nacional de Emisiones (INE), elaborado por el Ministerio de Medio Ambiente Rural y Marino (MARM), lo cual permite validar los datos y metodologías aplicados. Analizando globalmente los resultados, se obtiene que las emisiones derivadas del tráfico aéreo son superiores en los NMCOV, CO, CO2 y CH4, mientras que las operaciones de buques dentro de puertos producen mayores emisiones de NOx, SO2, PM10 y PM2.5. A nivel de infraestructuras, el aeropuerto de Madrid-Barajas es el que presenta una mayor cantidad de contaminantes primarios y GEIs emitidos. En cuanto a puertos, el de Barcelona es el que encabeza la lista de emisiones de contaminantes primarios, mientras que Bahía de Algeciras muestra la mayor cantidad de GEIs

HERMESv3, a stand-alone multi-scale atmospheric emission modelling framework – Part 1: global and regional module

Abstract Back to top We present the High-Elective Resolution Modelling Emission System version 3 (HERMESv3), an open source, parallel and stand-alone multi-scale atmospheric emission modelling framework that computes gaseous and aerosol emissions for use in atmospheric chemistry models. HERMESv3 is coded in Python and consists of a global_regional module and a bottom_up module that can be either combined or executed separately. In this contribution (Part 1) we describe the global_regional module, a customizable emission processing system that calculates emissions from different sources, regions and pollutants on a user-specified global or regional grid. The user can flexibly define combinations of existing up-to-date global and regional emission inventories and apply country-specific scaling factors and masks. Each emission inventory is individually processed using user-defined vertical, temporal and speciation profiles that allow obtaining emission outputs compatible with multiple chemical mechanisms (e.g. Carbon-Bond 05). The selection and combination of emission inventories and databases is done through detailed configuration files providing the user with a widely applicable framework for designing, choosing and adjusting the emission modelling experiment without modifying the HERMESv3 source code. The generated emission fields have been successfully tested in different atmospheric chemistry models (i.e. CMAQ, WRF-Chem and NMMB-MONARCH) at multiple spatial and temporal resolutions. In a companion article (Part 2; Guevara et al., 2019) we describe the bottom_up module, which estimates emissions at the source level (e.g. road link) combining state-of-the-art bottom–up methods with local activity and emission factors.The research leading to these results has received funding from the Ministerio de Economía y Competitividad (MINECO) as part of the PAISA project CGL2016-75725-R and the NUTRIENT project CGL2017-88911-R. The authors acknowledge PRACE for awarding access to Marenostrum4 based in Spain at the Barcelona Supercomputing Center through the Tier-0 HHRNTCP and Tier-0 EEDMC projects. Carlos Pérez García-Pando acknowledges long-term support from the AXA Research Fund, as well as the support received through the Ramón y Cajal programme (grant RYC-2015-18690) of the Spanish Ministry of Economy and Competitiveness. The authors would also like to thank the two anonymous referees for their thorough comments, which helped improve the quality of the paper.Peer ReviewedPostprint (published version