On equilibrium existence in infinite horizon economies

In sequential economies with finite or infinite-lived real assets in positive net supply, we introduce constraints on the amount of borrowing in terms of the market value of physical endowments. We show that, when utility functions are either unbounded and separable in states of nature or separable in commodities, these borrowing constraints not only preclude Ponzi schemes but also induce endogenous Radner bounds on short-sales. Therefore, we obtain existence of equilibrium. Moreover, equilibrium also exists when both assets are numerarie and utility functions are quasilinear in the commodity used as numerarie.Equilibrium, Infinite horizon incomplete markets, Infinite-lived real assets.

Infinite horizon economies with borrowing constraints

We consider infinite horizon economies with incomplete financial markets. Securities are in positive net supply and may be infinite-lived. We establish existence of equilibria by requiring borrowing constrains instead of portfolio restrictions..Equilibrium, Infinite horizon incomplete markets, Infinite-lived real assets.

Estrategias comunicativas de los anunciantes españoles frente a la covid-19

The crisis caused by COVID-19 seems to have caused major changes in advertising in our country. In this work we try to identify where these supposed changes have taken place and how they have affected the strategies of the main advertisers. We must bear in mind that our proposal is based on continuous monitoring of the activity of Spanish advertisers, which allows us to determine whether the changes that have occurred are truly important or whether this crisis (like the previous ones) has simply consolidated modifications or evolutions that were already gestating long ago. To meet this objective, we address three lines of work: bibliographic analysis, analysis of primary sources and applied field work on the campaigns of the main advertisers, in terms of investment, in Spain. With all this, we will be able to provide some initial conclusions about the response of advertisers, even creating a specific strategic model to be able to analyze the campaigns broadcast in this period and, above all, determine what strategy they respond to.The crisis caused by COVID-19 seems to have caused major changes in advertising in our country. In this work we try to identify where these supposed changes have taken place and how they have affected the strategies of the main advertisers. We must bear in mind that our proposal is based on continuous monitoring of the activity of Spanish advertisers, which allows us to determine whether the changes that have occurred are truly important or whether this crisis (like the previous ones) has simply consolidated modifications or evolutions that were already gestating long ago. To meet this objective, we address three lines of work: bibliographic analysis, analysis of primary sources and applied field work on the campaigns of the main advertisers, in terms of investment, in Spain. With all this, we will be able to provide some initial conclusions about the response of advertisers, even creating a specific strategic model to be able to analyze the campaigns broadcast in this period and, above all, determine what strategy they respond to.La crisis provocada por la COVID-19 parece haber provocado grandes cambios en lo relativo a la publicidad en nuestro país. En este trabajo intentamos identificar dónde se han producido esos supuestos cambios y cómo han afectado a las estrategias de los principales anunciantes. Debemos tener en cuenta que nuestra propuesta parte de un seguimiento continúo de la actividad de los anunciantes españoles, lo que permite determinar si los cambios que se han producido son verdaderamente importantes o si, simplemente, esta crisis (como las anteriores) ha consolidado modificaciones o evoluciones que ya se gestaban tiempo atrás. Para hacer frente a este objetivo abordamos tres líneas de trabajo: el análisis bibliográfico, el análisis de fuentes primarias y el trabajo de campo aplicado sobre las campañas de los principales anunciantes, en términos de inversión, de España. Con todo ello podremos aportar unas conclusiones iniciales sobre la respuesta de los anunciantes creando incluso un modelo estratégico específico para poder analizar las campañas difundidas en este periodo y, sobre todo, determinar a qué estrategia responden

Time-dependent modeling of TeV-detected, young pulsar wind nebulae

The increasing sensitivity of instruments at X-ray and TeV energies have revealed a large number of nebulae associated with bright pulsars. Despite this large data set, the observed pulsar wind nebulae (PWNe) do not show a uniform behavior and the main parameters driving features like luminosity, magnetization, and others are still not fully understood. To evaluate the possible existence of common evolutive trends and to link the characteristics of the nebula emission with those of the powering pulsar, we selected a sub-set of 10 TeV detections which are likely ascribed to young PWNe and model the spectral energy distribution with a time-dependent description of the nebulae's electron population. In 9 of these cases, a detailed PWNe model, using up-to-date multiwavelength information, is presented. The best-fit parameters of these nebula are discussed, together with the pulsar characteristics. We conclude that TeV PWNe are particle-dominated objects with large multiplicities, in general far from magnetic equipartition, and that relatively large photon field enhancements are required to explain the high level of Comptonized photons observed. We do not find significant correlations between the efficiencies of emission at different frequencies and the magnetization. The injection parameters do not appear to be particularly correlated with the pulsar properties either. We find that a normalized comparison of the SEDs (e.g., with the corresponding spin-down flux) at the same age significantly reduces the spectral distributions dispersion.Comment: 38 pages, 20 figures, 8 tables. Accepted for publication in the Journal of High Energy Astrophysics (JHEAp

Gamma-ray upper limits on magnetars with 6 years of Fermi-LAT observations

We report on the search for gamma-ray emission from 20 magnetars using 6 years of Fermi, Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently-known magnetars is found. We derived the most stringent upper limits to date on the 0.1--10 GeV emission of Galactic magnetars, which are estimated between $\sim10^{-12}-10^{-11}$ erg s$^{-1}$ cm$^{-2}$. Gamma-ray pulsations were searched for the four magnetars having reliable ephemerides over the observing period, but none were detected. On the other hand, we also studied the gamma-ray morphology and spectra of seven Supernova Remnants associated or adjacent to the magnetars.Comment: 22 pages, 4 figures, 2 tables, submitted to Ap

La sustentabilidad agrícola de las chinampas en el Valle de México: caso Xochimilco

El objetivo de esta investigación es mostrar los rasgos de sustentabilidad de la práctica chinampera en el Valle de México: Xochimilco, a través de un diagnóstico FODA para revelar la trascendencia ambiental del modelo agrícola. Se puede apreciar que el desarrollo de las chinampas tiene básicamente dos componentes; uno natural y otro social. El primero lo constituye la naturaleza del lugar. El segundo concierne lo social, es decir a la forma en que se organiza el trabajo, las prácticas culturales de cultivo y la implementación de métodos y tecnologías agrícolas que son el resultado de la sabiduría milenaria de los grupos autóctonos de las zonas chinamperas. Lo cual ha contribuido a mantener la integración de los miembros de la familia, así como de dar auto empleo y generación autoalimentaría, estos rasgos muestran que este sistema de producción agrícola es sustentable en lo ambiental, social y económico. Sin embargo la producción chinampera está sometida por diversos aspectos como; el desarrollo de la tecnología de la agricultura moderna, el crecimiento urbano y la contaminación del agua

Gamma-ray emission from PSR J0007+7303 using 7 years of Fermi Large Area Telescope observations

Based on more than seven years of Fermi Large Area Telescope (LAT) Pass 8 data, we report on a detailed analysis of the bright gamma-ray pulsar (PSR) J0007+7303. We confirm that PSR J0007+7303 is significantly detected as a point source also during the off-peak phases with a TS value of 262 ($\sim$ 16 $\sigma$). In the description of PSR J0007+7303 off-peak spectrum, a power law with an exponential cutoff at 2.7$\pm$1.2$\pm$1.3 GeV (the first/second uncertainties correspond to statistical/systematic errors) is preferred over a single power law at a level of 3.5 $\sigma$. The possible existence of a cutoff hints at a magnetospheric origin of the emission. In addition, no extended gamma-ray emission is detected compatible with either the supernova remnant (CTA 1) or the very high energy (> 100 GeV) pulsar wind nebula. A flux upper limit of 6.5$\times$10$^{-12}$ erg cm$^{-2}$ s$^{-1}$ in the 10-300 GeV energy range is reported, for an extended source assuming the morphology of the VERITAS detection. During on-peak phases, a sub-exponential cutoff is significantly preferred ($\sim$11 $\sigma$) for representing the spectral energy distribution, both in the phase-averaged and in the phase-resolved spectra. Three glitches are detected during the observation period and we found no flux variability at the time of the glitches or in the long-term behavior. We also report the discovery of a previously unknown gamma-ray source in the vicinity of PSR J0007+7303, Fermi J0020+7328, which we associate with the z = 1.781 quasar S5 0016+73. A concurrent analysis of this source is needed to correctly characterize the behavior of CTA 1 and it is also presented in the paper.Comment: 26 pages, 10 figures, 4 tables; Accepted for publication in Ap

Strategist Advertising evolution. From brand management to personalized brand and consumers new role

El presente trabajo de investigación pretende realizar un repaso por los cambios que se han podido producir en los procesos de planificación estratégica publicitaria. Para ese fin se ha realizado un seguimiento de las principales tendencias comunicativas en este ámbito, intentando identificar los modelos actuales para poder así, comparar la realidad actual con lo que sucedía antes de la crisis. El punto de partida en este caso está en el hecho de que, tal y como preveía la Nueva Teoría Estratégica, la recuperación del ser humano es la base del funcionamiento de la estrategia publicitaria actual, donde las marcas deben adaptarse a las preferencias del consumidor de una forma casi individual y los mensajes deben dirigirse a un consumidor más crítico y con un mayor manejo de las herramientas comunicativas que lo convierten en un prosumidor. Se trata de un ejercicio complejo realizado quizá en el momento en el que se están produciendo los cambios más profundos en el sector.The present work of investigation to try to realize a revision for the changes that they could have produced in the processes of strategic advertising planning. For this end there has been realized a follow-up of the principal communicative trends in this area, trying to identify the current models to be able this way, to compare the current reality with what it was happening before the crisis. The point of item in this case is in the fact that, as it was foreseeing the New Strategic Theory, the recovery of the human being is the base of the functioning of the advertising current strategy, where the brands must adapt to the preferences of the consumer of an almost individual form, and the messages must go to a more critical consumer and with a major managing of the communicative tools that turn it into a prosumer. It is a question of a complex exercise realized probably in the moment in which the deepest changes are taking place in the sector