Redistribution of particle and anti-particle entanglement in non-inertial frames

We analyse the entanglement tradeoff between particle and anti-particle modes of a Dirac field from the perspective of inertial and uniformly accelerated observers. Our results show that a redistribution of entanglement between particle and anti-particle modes plays a key role in the survival of fermionic field entanglement in the infinite acceleration limit.Comment: 10 pages, 5 figures, revtex4. Added journal referenc

On the optimal level of public inputs.

This paper studies the optimal level of public inputs under two different tax settings. With this aim, we adapt the approach by Gronberg and Liu (2001) to the case of productivity-enhancing public spending. We find that it is not analytically clear whether the first-best level of public spending exceeds the second-best level. After taking account the type of public input, a wide numerical simulation has been carried out. We obtain that the second-best level is always below the first-best level but the criterion by Gronberg and Liu has to be qualified.Second best, excess burden, public input.

Optimization in non-standard problems. An application to the provision of public inputs

This paper describes a new method for solving non-standard constrained optimization problems for which standard methodologies do not work properly. Our method (the Rational Iterative Multisection -RIM- algorithm) consists of different stages that can be interpreted as different requirements of precision by obtaining the optimal solution. We have performed an application of RIM method to the case of public inputs provision. We prove that the RIM approach and comparable standard methodologies achieve the same results with regular optimization problems while the RIM algorithm takes advantage over them when facing non-standard optimization problems.direct search, constrained optimization, multisection, optimal taxation, public input.

How sensitive is the provision of public inputs to specifications?

This paper studies the sensitivity of provision of public inputs to changes in the specification of technology and consumer preferences. We consider a simple model in which the government, with recourse to three different tax settings (a lump-sum tax, a tax on labour and a tax on economic profit), provides firms with certain productive services. We focus on the numerical results coming from the government optimization problem. We look at several specific cases in which the returns to scale in the production function emerges as a critical issue. Our …findings also address the impact of changes in output elasticity, in consumer preferences and in the number of households on the levels of public input and utility.firm-augmenting public input, factor-augmenting public input, optimal provision

Germinació de llavors d'espècies psammòfiles i ruderals de platja

S’ha estudiat la capacitat de germinació dels propàguls de quatre espècies (Cenchrus incertus, Tribulus terrestris, Pancratium maritimum i Xanthium strumarium), un cop se’ls ha sotmès a diferents situacions: cap tractament previ, un cop de calor amb aigua bullint i una immersió en àcid sulfúric (aquest darrer només en el cas de C. incertus). Les condicions de fotoperíode han estat 12 h llum/12 h fosc, i 24 h foscor, i la temperatura ha estat constant (25 ºC). Les llavors han estat sembrades en sorra o placa de Petri. També s’ha estudiat la capacitat de germinació de les espiguetes de Digitaria sanguinalis en funció de la profunditat d’enterrament sota unes condicions ambientals determinades (20-30 ºC i 12 h llum/12 h foscor). Els resultats més destacables han estat els següents: - Tribulus terrestris L. Les llavors de T. terrestris es mantenen latents en un 100 % després de sotmetre’s a les condicions de germinació i tractaments esmentats. - Cenchrus incertus L. El tractament de cop de calor en C. incertus manté les llavors latents en un 100 %. El tractament d’àcid sulfúric permet percentatges de germinació al voltant del 25 %, per sota dels lots no tractats, en els quals el percentatge mitjà de germinació volta el 36,37 %. - Pancratium maritimum L. El tractament de cop de calor manté el 100 % de les llavors latents. En condicions de laboratori poden mostrar una germinació mitjana superior al 86%. - Xanthium strumarium L. El tractament de cop de calor provoca un retard i una disminució del percentatge de germinació respecte les llavors no tractades. En les condicions de l’assaig s’han obtingut percentatges del 93 % d’unitats de dispersió eclosionades, amb un 48,81 % de germinacions, en aquelles llavors que no han patit cap tractament. - Digitaria sanguinalis (L.) Scop. Digitaria sanguinalis és capaç de germinar enterrada en profunditats de 0 a 10 cm, però només és capaç d’emergir quan la llavor es troba enterrada entre 0 i 2 cm

Fuzzy Inference System for VOLT/VAR control in distribution substations in isolated power systems

This paper presents a fuzzy inference system for voltage/reactive power control in distribution substations. The purpose is go forward to automation distribution and its implementation in isolated power systems where control capabilities are limited and it is common using the same applications as in continental power systems. This means that lot of functionalities do not apply and computational burden generates high response times. A fuzzy controller, with logic guidelines embedded based upon heuristic rules resulting from operators at dispatch control center past experience, has been designed. Working as an on-line tool, it has been tested under real conditions and it has managed the operation during a whole day in a distribution substation. Within the limits of control capabilities of the system, the controller maintained successfully an acceptable voltage profile, power factor values over 0,98 and it has ostensibly improved the performance given by an optimal power flow based automation system

Diversity of quinoa in a biogeographical Island: A review of constraints and potential from arid to temperate regions of Chile

Chile, isolated by a hyper-arid desert in the north, the Andes Range to the east and the Pacific and Antarctic waters (west and south), has a highly endemic flora. This hotspot of biodiversity is in danger not only due to increasing desertification, but also because human activities can diminish agrobiodiversity. Quinoa (Chenopodium quinoa Willd.) is an Andean species producing highly nutritious grains, which almost disappeared from Chile during the Spanish colonization. Today less than 300 small-scale and highly isolated farmers still grow it as a rain-fed crop. This review describes the biogeographical-social context of quinoa in Chile, and its high genetic diversity as a product of a long domestication process, resulting in numerous local landraces whose conservation and use for breeding improved varieties is of paramount importance. We suggest the term "lighthouse crop" to emphasize its contribution to small scale ecological and bio diverse agriculture, particularly in stressful environments, to promote a healthier nutrition and more equitable markets in the world. Furthermore this crop and its exceptional nutritional properties were invoked by the United Nations Food and Agriculture Organization (FAO) to promote its use worldwide, and to declare 2013 the International Year of Quinoa. (Résumé d'auteur