Evidence for precession of the isolated neutron star RX J0720.4-3125

The XMM-Newton spectra of the isolated neutron star RX J0720.4-3125 obtained over 4.5 years can be described by sinusoidal variations in the inferred blackbody temperature, the size of the emitting area and the depth of the absorption line with a period of 7.1 +/- 0.5 years, which we suggest to be the precession period of the neutron star. Precession of a neutron star with two hot spots of different temperature and size, probably not located exactly in antipodal positions, may account for the variations in the X-ray spectra, changes in the pulsed fraction, shape of the light curve and the phase-lag between soft and hard energy bands observed from RX J0720.4-3125. An independent sinusoidal fit to published and new pulse timing residuals from a coherent analysis covering ~12 years yields a consistent period of 7.7 +/- 0.6 years supporting the precession model.Comment: Accepted for publication in A&A Letters, 5 pages, 5 figure

Targeting energy savings? Better on primary than final energy and less on intensity metrics

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGA eficiencia enerxética é un tema crítico nas políticas públicas, xa que é a clave para desvincular o crecemento económico e o uso da enerxía. Estes obxectivos están a ser aínda máis relevantes para abordar a crise enerxética e os novos escenarios xeopolíticos da guerra de Ucraína. Aínda que varios traballos analizaron os obxectivos de eficiencia enerxética, este traballo céntrase nos obxectivos de aforro enerxético, que representan a principal métrica de eficiencia para a Unión Europea. Este traballo enche un baleiro na literatura ao analizar os impactos económicos e ambientais da consecución de obxectivos de eficiencia enerxética mediante unha política fiscal enerxética, simulada por un modelo de equilibrio xeral computable híbrido con gran detalle tecnolóxico. Defínense seis escenarios para o aforro enerxético no consumo dos produtos enerxéticos, utilizando Portugal como caso de estudo. Os resultados relevantes para os responsables políticos dos escenarios simulados inclúen: (i) acadar obxectivos de aforro enerxético por medios alternativos, é dicir, dirixidos ao consumo de enerxía primaria ou final, proporcionar impactos heteroxéneos na eficiencia do sistema enerxético e no PIB, e algúns inesperados e indesexables nos impactos ambientais; (ii) unha fiscalidade relativamente máis baixa de todos os produtos enerxéticos produce impactos máis grandes e máis distorsionadores na xeración de electricidade que impostos máis elevados só sobre os combustibles fósiles (un resultado contraintuitivo), (iii) as políticas destinadas a reducir a enerxía primaria en lugar da enerxía final proporcionan os mellores resultados (maiores aumentos da eficiencia do sistema enerxético con impactos económicos máis suaves), o que vai en contra do principio da directiva europea sobre impostos enerxéticos pola que deben gravarse os produtos finais, independentemente dos insumos utilizados na súa produción e (iv) e os obxectivos non deben elaborarse en base a indicadores de intensidade enerxética. Polo tanto, móstrase que o tamaño dos impactos no balance entre as preocupacións económicas e ambientais depende do foco no aforro enerxético: de onde (consumo de enerxía primaria ou final) e a que (fósiles ou todos os produtos enerxéticos) sexa aplicado.Energy efficiency is a critical issue in public policies, as it is the key to decoupling economic growth and energy use. These objectives are becoming even more relevant to addressing the energy crisis and the new geopolitical scenarios delivered by the Ukraine war. Although several papers have analyzed energy efficiency goals, this paper focuses on energy savings targets, which represent the main efficiency metric for the European Union. This paper fills a gap in literature by analyzing the economic and environmental impacts of attaining energy efficiency targets through an energy fiscal policy, simulated by a hybrid computable general equilibrium model with technological detail. Six scenarios are defined for energy savings in primary/final energy consumption of fossil-fueled/all energy products, using Portugal as a case study. Relevant insights for policy makers from the simulated scenarios include: (i) achieving energy saving targets by alternative means, i.e., directed at primary or final energy consumption, provide heterogeneous impacts on the efficiency of the energy system and GDP, and some unexpected and undesirable outcomes concerning environmental impacts; (ii) a relatively lower taxation of all energy products deliver larger and more distorting impacts on electricity generation than higher taxes on fossil fuels only (a counterintuitive result), (iii) policies aiming to reduce primary energy instead of final energy provide the best outcomes (further increases in the efficiency of the energy system with smoother economic impacts), thereby pointing against the European Energy Taxation directive principle that taxation should be levied on final products, regardless of inputs used in their production and (iv) and targets should not be set up based on energy intensity indicators. Hence, it is shown that the size of the trade-off between economic and environmental concerns depends on where (primary or final energy consumption) and what (fossil or all energy products) energy savings are targeted.Fundação para a Ciência e a Tecnologia | Ref. UIDB/05037/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/05037/2020Fundação para a Ciência e a Tecnologia | Ref. UID/04085/2020Ministerio de Ciencia y Educación | Ref. PID2019-106677GB-I00Xunta de Galicia | Ref. GRC2017/063Universidade de Vigo/CISU

Detection, photometry and slitless radial velocities of 535 planetary nebulae in the flattened elliptical galaxy NGC 4697

We have detected 535 planetary nebulae (PNs) in NGC 4697, using the classic on-band, off-band filter technique with the Focal Reducer and Spectrograph (FORS) at the Cassegrain focus of the first 8-meter telescope unit of the ESO Very Large Telescope. From our photometry we have built the [O III] 5007 planetary nebula luminosity function (PNLF) of NGC 4697. It indicates a distance of 10.5 Mpc, substantially smaller than a previous estimate of 24 Mpc used in earlier dynamical studies. The PNLF also provides an estimate of the specific PN formation rate. Combining the information from on-band images with PN positions on dispersed, slitless grism images, we have obtained radial velocities for 531 of the 535 PNs. They provide kinematic information up to a distance of almost three effective radii from the nucleus. Some rotation is detected in the outer regions, but the rotation curve of this galaxy appears to drop beyond one effective radius. Assuming an isotropic velocity distribution, the velocity dispersion profile is consistent with no dark matter within three effective radii of the nucleus (however, some dark matter can be present if the velocity distribution is anisotropic). We obtain a blue mass-to-light ratio of 11. Earlier M/L ratios for NGC 4697 were too small, because of the too large distance used for their derivation.Comment: 52 pages, 24 Postscript figures, ApJ 2001, in pres

Reingeniería técnica administrativa y financiera de global sociedad financiera

Las organizaciones son tan eficaces y eficientes como sus procesos. Las empresas han tomado conciencia de esto y plantean cómo mejorar dichos procesos y evitar algunos males habituales tales como: poco enfoque al cliente, bajo rendimiento de los procesos, barreras departamentales, subprocesos inútiles debido a la falta de visión global del proceso. El proyecto se inicia en un momento en que la organización está atravesando un cambio de estrategia importante, que debe suponer un incremento en cuanto a la cercanía con los clientes y estándares de servicio. Para prosperar, las empresas deben adaptarse a los cambios del entorno. Un entorno difícil de predecir, un cambio veloz, crecimiento competitivo y mucho más exigente (los clientes, los accionistas y la comunidad pretenden cada vez más). El concepto fundamental, dicho en palabras breves, es que la empresa necesita provocar un cambio para mejorar su competitividad. Es por esto que se realizo un análisis profundo de las necesidades de cambio de la sociedad financiera realizando estudios técnicos administrativos y financieros que ayudaran a medir el estado de la empresa y con esto realiza los cambios necesarios para poder seguir en la competencia del mercado financiero y llegar a ocupar un puesto representativo en este

Multi-screen and multi-device game development

Users are interacting with an increasing number of devices and screens. However, these screens are usually used independently without collaboration between them. Although there have been several advances in multi-screen applications the game community does not seem to have fully explored this opportunity as yet. This paper presents an approach for the development of mobile multi-screen and multi-device games. The approach aims to enable and foster the creation of multi-device games sharing information via a centralized screen and is demonstrated by means of an example, the well-known Casino Roulette game. The results of a preliminary evaluation of the game are also presented.info:eu-repo/semantics/acceptedVersio

More evidence for an intracluster planetary nebulae population in the Virgo cluster

We surveyed a 50 sq arcmin region in the Virgo cluster core to search for intergalactic planetary nebulae, and found 11 candidates in the surveyed area. The measured fluxes of these unresolved sources are consistent with these objects being planetary nebulae from an intracluster population of stars. We compute the cumulative luminosity function of these 11 planetary nebula candidates. If we assume that they belong to the Virgo cluster, their cumulative luminosity function is in good agreement with planetary nebula luminosity function simulations. This comparison allows us to estimate the surface mass density of the intracluster stellar population at the surveyed field in the cluster core.Comment: ApJ Letters, in press. A .ps file is also available at: http://www.usm.uni-muenchen.de:8001/people/mendez/preprints/preprints.htm

Coupled radio and X-ray emission and evidence for discrete ejecta in the jets of SS 433

We present five epochs of simultaneous radio (VLA) and X-ray (Chandra) observations of SS 433, to study the relation between the radio and X-ray emission in the arcsecond-scale jets of the source. We detected X-ray emission from the extended jets in only one of the five epochs of observation, indicating that the X-ray reheating mechanism is transient. The reheating does not correlate with the total flux in the core or in the extended radio jets. However, the radio emission in the X-ray reheating regions is enhanced when X-ray emission is present. Deep images of the jets in linear polarization show that outside of the core, the magnetic field in the jets is aligned parallel to the local velocity vector, strengthening the case for the jets to be composed of discrete bullets rather than being continuous flux tubes. We also observed anomalous regions of polarized emission well away from the kinematic trace, confirming the large-scale anisotropy of the magnetic field in the ambient medium surrounding the jets.Comment: Accepted for publication in ApJ. 11 pages (emulateapj), 9 figures, 3 table

Correlated Timing and Spectral Variations of the Soft X-ray Transient Aquila X-1: Evidence for an Atoll classification

Based on Rossi X-ray Timing Explorer data, we discuss the classification of the soft X-ray transient Aquila X-1 in the Z/atoll scheme, and the relation of its kilohertz quasi-periodic oscillations (kHz QPO) properties to the X-ray colors. The color-color diagram shows one elongated ("banana") structure and several "islands" of data points. The power spectra of the island are best represented by a broken power-law, whereas those of the banana by a power-law below ~ 1 Hz plus an exponentially cut-off component at intermediate frequencies (30-60 Hz). The parameters of these two components change in correlation with the position of the source in the color-color diagram. Based on the pattern that the source shows in the color-color diagram and its aperiodic variability we conclude that Aquila X-1 is an atoll source. We have also investigated the possible correlation between the frequency of the kHz QPO and the position of the source in the color-color diagram. The complexity seen in the frequency versus count rate diagram is reduced to a single track when the frequency is plotted against hard or soft color.Comment: 9 pages, 5 figures. Accepted for publication in Ap