990 resultados para Direct broadcast satellite television


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Background: Sedentary behaviors, particularly television viewing (TV) time, are associated with adverse health outcomes in adults, independent of physical activity levels. These associations are stronger and more consistent for women than for men. Methods: Multivariate regression models examined the sociodemographic correlates of 2 categories of TV time (≥2 hours/day and ≥4 hours/day); in a large, population-based sample of Australian adults (4950 men, 6001 women; mean age 48.1 years, range 25-91) who participated in the 1999/2000 Australian Diabetes, Obesity, and Lifestyle (AusDiab) study. Results: Some 46% of men and 40% of women watched ≥ 2 hours TV/day; 9% and 6% respectively watched ≥ 4 hours/day. For both men and women, ≥2 hours TV/day was associated with less than tertiary education, living outside of state capital cities, and having no paid employment. For women, mid and older age (45-64 and 65+) were also significant correlates of ≥2 hours TV/day. Similar patterns of association were observed in those viewing ≥4 hours/day. Conclusions: Prolonged TV time is associated with indices of social disadvantage and older age. These findings can inform the understanding of potential contextual influences and guide preventive initiatives.

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Focus groups of nurses from both in-centre and satellite dialysis units were undertaken followed by questionnaires. The In-centre nursing staff rated the busy-ness of the unit as the maximum stress. The mostly notable stressor for the staff at the satellite unit related to patient behaviour and the perceived unrealistic expectations of the patient followed by patients arriving unwell at the unit.

Nurses suffer stress on a daily basis in both in-centre and satellite dialysis units. The major stressors differ from in-centre to satellite dialysis units.

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Australia is in the midst of a massive transformation of its communication infrastructure. The AUD43 billion Australian National Broadband Network (NBN) to be set up by the wholly Federal government-owned NBNCo Limited (NBNCo), is the largest infrastructure project ever proposed in Australia (NBN, 2010). It has the capacity to combine features and technologies that were once separate, but now have converged, including computing, telephony, free-to-air (FTA) television, direct-to-home satellite broadcasting, radio and the internet. This means that current thinking about these media technologies, developed through the process of convergence as well as regulation, requires review. Future services for digital television are going to be more akin to app-based functions currently available on mobiles and tablets but accessed via the television screen rather than the PC. Against such a background, this article examines the Australian ‘televisual’ space, arguing that faster broadband and internet-enabled televisions for movies, shows, communication and more, when it suits the audience, are the keys to television’s survival through visually networked possibilities.

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This paper traces the development of children’s multiplatform commissioning at the Australian Broadcasting Corporation (ABC) in the context of the digitalisation of Australian television. Whilst recent scholarship has focussed on ‘post-broadcast’ or ‘second-shift’ industrial practices, designed to engage view(s)ers with proprietary media brands, less attention has been focussed on children’s and young adults’ television in a public service context. Further, although multiplatform projects in the United States and Britain have been the subject of considerable analysis, less work has attempted to contextualise cultural production in smaller media markets. The paper explores two recent multiplatform projects through textual analysis, empirical research (consisting of interviews with key industry personnel) and an investigation of recent policy documents. The authors argue that the ABC’s mixed diet of children’s programming, featuring an educative or social developmental agenda, is complemented by its appeals to audience ‘participation’, with the Corporation maintaining public service values alongside the need to expand audience reach and the legitimacy of its brand. It finds that the ABC’s historical platform infrastructure, across radio, television and online, have allowed it to move beyond a market failure model to exploit multiplatform synergies competitively in the distribution of Australian children’s content to audiences on-demand.

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In India, not unlike some other developing countries, ruling parties have used public service broadcasters to propagate their virtues, adversely affecting the broadcasters' image as a credible news media. The Indian public service broadcaster. Doordarshan,
which has been besieged by increased competition and government-imposed demandfor selfsufficiency in recent years, continues to struggle to shed its image as a government mouthpiece despite being run by an independent corporation. This article
presents a content analysis of news programs broadcast by Doordarshan and a foreign television network. Star News. The study examines the differences and similarities between Doordarshan and Star TV's prime time news programs broadcast at the turn ofthe century, almost a decade after the advent ofcommercial television in India broke the public service broadcaster's monopoly in the country.

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Long-term records of nesting numbers, or proxies to nesting numbers, show a precipitous decline in the size of many sea turtle populations. Population declines are most frequently attributed to fisheries bycatch, although direct quantification of this level of mortality is rare. We used satellite-tracking records for turtles in the Mediterranean Sea and Pacific, Atlantic and Indian Oceans to identify when turtles had been captured. Evidence for capture came from a combination of an increase in good quality locations from transmitters, transmitters moving inland to coastal towns and villages, and on-board submergence data, showing that transmitters had come out of the water. A high level of mortality was calculated, confirming current concerns regarding the outlook for sea turtles.

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The rotational motion of an artificial satellite is studied by considering torques produced by gravity gradient and direct solar radiation pressure. A satellite of circular cylinder shape is considered here, and Andoyers variables are used to describe the rotational motion. Expressions for direct solar radiation torque are derived. When the earth's shadow is not considered, an analytical solution is obtained using Lagrange's method of variation of parameters. A semi-analytical procedure is proposed to predict the satellite's attitude under the influence of the earth's shadow. The analytical solution shows that angular variables are linear and periodic functions of time while their conjugates suffer only periodic variations. When compared, numerical and analytical solutions have a good agreement during the time range considered.

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A formulation used to determine the time-optimal geomagnetic attitude maneuvers subject to dynamic and geometric constraints is proposed in this paper. This was obtained by a direct search procedure based on a control function parametrization method, using linear programming to obtain numerical suboptimal solutions by linear perturbation. Due to its characteristics it can be used in small computers and to generate computer programs of general application. The dynamic modeling, the magnetic torque model and the suboptimal control procedure are presented. Simulation runs have verified the feasibility of the formulation thus derived and have shown a notable improvement in performance.

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An analytical expansion of the disturbing function arising from direct planetary perturbations on the motion of satellites is derived. As a Fourier series, it allows the investigation of the secular effects of these direct perturbations, as well as of every argument present in the perturbation. In particular, we construct an analytical model describing the evection resonance between the longitude of pericenter of the satellite orbit and the longitude of a planet, and study briefly its dynamic. The expansion developed in this paper is valid in the case of planar and circular planetary orbits, but not limited in eccentricity or inclination of the satellite orbit. © 2012 Springer Science+Business Media Dordrecht.

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Pós-graduação em Artes - IA

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In this report it was designed an innovative satellite-based monitoring approach applied on the Iraqi Marshlands to survey the extent and distribution of marshland re-flooding and assess the development of wetland vegetation cover. The study, conducted in collaboration with MEEO Srl , makes use of images collected from the sensor (A)ATSR onboard ESA ENVISAT Satellite to collect data at multi-temporal scales and an analysis was adopted to observe the evolution of marshland re-flooding. The methodology uses a multi-temporal pixel-based approach based on classification maps produced by the classification tool SOIL MAPPER ®. The catalogue of the classification maps is available as web service through the Service Support Environment Portal (SSE, supported by ESA). The inundation of the Iraqi marshlands, which has been continuous since April 2003, is characterized by a high degree of variability, ad-hoc interventions and uncertainty. Given the security constraints and vastness of the Iraqi marshlands, as well as cost-effectiveness considerations, satellite remote sensing was the only viable tool to observe the changes taking place on a continuous basis. The proposed system (ALCS – AATSR LAND CLASSIFICATION SYSTEM) avoids the direct use of the (A)ATSR images and foresees the application of LULCC evolution models directly to „stock‟ of classified maps. This approach is made possible by the availability of a 13 year classified image database, conceived and implemented in the CARD project (http://earth.esa.int/rtd/Projects/#CARD).The approach here presented evolves toward an innovative, efficient and fast method to exploit the potentiality of multi-temporal LULCC analysis of (A)ATSR images. The two main objectives of this work are both linked to a sort of assessment: the first is to assessing the ability of modeling with the web-application ALCS using image-based AATSR classified with SOIL MAPPER ® and the second is to evaluate the magnitude, the character and the extension of wetland rehabilitation.

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Hall thrusters have been under active development around the world since the 1960’s. Thrusters using traditional propellants such as xenon have been flown on a variety of satellite orbit raising and maintenance missions with an excellent record. To expand the mission envelope, it is necessary to lower the specific impulse of the thrusters but xenon and krypton are poor performers at specific impulses below 1,200 seconds. To enhance low specific impulse performance, this dissertation examines the development of a Hall-effect thruster which uses bismuth as a propellant. Bismuth, the heaviest non-radioactive element, holds many advantages over noble gas propellants from an energetics as well as a practical economic standpoint. Low ionization energy, large electron-impact crosssection and high atomic mass make bismuth ideal for low-specific impulse applications. The primary disadvantage lies in the high temperatures which are required to generate the bismuth vapors. Previous efforts carried out in the Soviet Union relied upon the complete bismuth vaporization and gas phase delivery to the anode. While this proved successful, the power required to vaporize and maintain gas phase throughout the mass flow system quickly removed many of the efficiency gains expected from using bismuth. To solve these problems, a unique method of delivering liquid bismuth to the anode has been developed. Bismuth is contained within a hollow anode reservoir that is capped by a porous metallic disc. By utilizing the inherent waste heat generated in a Hall thruster, liquid bismuth is evaporated and the vapors pass through the porous disc into the discharge chamber. Due to the high temperatures and material compatibility requirements, the anode was fabricated out of pure molybdenum. The porous vaporizer was not available commercially so a method of creating a refractory porous plate with 40-50% open porosity was developed. Molybdenum also does not respond well to most forms of welding so a diffusion bonding process was also developed to join the molybdenum porous disc to the molybdenum anode. Operation of the direct evaporation bismuth Hall thruster revealed interesting phenomenon. By utilizing constant current mode on a discharge power supply, the discharge voltage settles out to a stable operating point which is a function of discharge current, anode face area and average pore size on the vaporizer. Oscillations with a 40 second period were also observed. Preliminary performance data suggests that the direct evaporation bismuth Hall thruster performs similar to xenon and krypton Hall thrusters. Plume interrogation with a Retarding Potential Analyzer confirmed that bismuth ions were being efficiently accelerated while Faraday probe data gave a view of the ion density in the exhausted plume.

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While sound and video may capture viewers' attention, interaction can captivate them. This has not been available prior to the advent of Digital Television. In fact, what lies at the heart of the Digital Television revolution is this new type of interactive content, offered in the form of interactive Television (iTV) services. On top of that, the new world of converged networks has created a demand for a new type of converged services on a range of mobile terminals (Tablet PCs, PDAs and mobile phones). This paper aims at presenting a new approach to service creation that allows for the semi-automatic translation of simulations and rapid prototypes created in the accessible desktop multimedia authoring package Macromedia Director into services ready for broadcast. This is achieved by a series of tools that de-skill and speed-up the process of creating digital TV user interfaces (UI) and applications for mobile terminals. The benefits of rapid prototyping are essential for the production of these new types of services, and are therefore discussed in the first section of this paper. In the following sections, an overview of the operation of content, service, creation and management sub-systems is presented, which illustrates why these tools compose an important and integral part of a system responsible of creating, delivering and managing converged broadcast and telecommunications services. The next section examines a number of metadata languages candidates for describing the iTV services user interface and the schema language adopted in this project. A detailed description of the operation of the two tools is provided to offer an insight of how they can be used to de-skill and speed-up the process of creating digital TV user interfaces and applications for mobile terminals. Finally, representative broadcast oriented and telecommunication oriented converged service components are also introduced, demonstrating how these tools have been used to generate different types of services.

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We report the first in situ measurements of neutral deuterium originating in the local interstellar medium (LISM) in Earth’s orbit. These measurements were performed with the IBEX-Lo camera on NASA’s interstellar boundary explorer (IBEX) satellite. All data from the spring observation periods of 2009 through 2011 have been analysed. In the three years of the IBEX mission time, the observation geometry and orbit allowed for a total observation time of 115.3 days for the LISM. However, the effects of the spinning spacecraft and the stepping through 8 energy channels mean that we are only observing the interstellar wind for a total time of 1.44 days, in which 2 counts for interstellar deuterium were collected. We report here a conservative number, because a possibility of systematic error or additional noise, though eliminated in our analysis to the best of our knowledge, only supports detection at a 1-sigma level. From these observations, we derive a ratio D/H = (5.8 ± 4.4) × 10-4 at 1 AU. After modelling the transport and loss of D and H from the termination shock to Earth’s orbit, we find that our result of D/HLISM = (1.6 ± 1.2) × 10-5 agrees with D/HLIC = (1.6 ± 0.4) × 10-5 for the local interstellar cloud. This weak interstellar signal is extracted from a strong terrestrial background signal consisting of sputter products from the sensor’s conversion surface. As reference, we accurately measure the terrestrial D/H ratio in these sputtered products and then discriminate this terrestrial background source. Because of the diminishing D and H signal at Earth’s orbit during the rising solar activity due to photoionisation losses and increased photon pressure, our result demonstrates that in situ measurements of interstellar deuterium in the inner heliosphere are only possible during solar minimum conditions.