Position reporting system using small satellites

A system able to provide position reporting and monitoring services for mobile applications represents a natural complement to the Global Positioning System (GPS) navigation system. The system architecture is defined on the basis of the communications requirements derived by user needs, allowing maximum flexibility in the use of channel capacity, and a very simple and low cost terminal. The payload is sketched, outlining the block modularity and the use of qualified hardware. The global system capacity is also derived. The spacecraft characteristics are defined on the basis of the payload requirements. A small bus optimized for Ariane IV, Delta II vehicles and based on the modularity concept is presented. The design takes full advantage of each launcher with a common basic bus or bus elements for a mass production

MINISTAR: A Small Spacecraft for GEO Missions

This paper provides the information of the conceptual design of MINISTAR and presents the major features of this small spacecraft, able to support geostationary missions for satellite communications. MINISTAR is a sun pointing satellite, with despun antenna provided with momentum wheels to achieve gyroscopic stiffness along the pitch axis, maintained orthogonal to the geosynchronous orbit. Thrusters supply the attitude stabilization for yaw and roll axes and station keeping maneuvers. An unified propulsion system is adopted, with helium pressurized bipropellant. The system makes use of monomethyhl hydrazine as propellant and nitrogen tetroxide as oxidizer. Large autonomy is provided by the on-board system management. The communications\u27 payload power/mass ranges from 200 W/50 Kg to 600 W/100 Kg allowing payloads with volume of 0.13 m3 and a maximum antenna diameter of 1.8 m. MINISTAR can be launched as co-passenger by ARIANE or TITAN

Low Cost Station Keeping Maneuvers for a Small-Satellites Constellation in TUNDRA Orbits

A constellation of three small satellites placed, in highly inclined geosynchronous eccentric orbits equally spaced, can provide a continuous coverage of a service zone at high latitudes. Satellites on such orbits (TUNDRA) will spend most of the time around the apogee and each satellite of the constellation is required to be at a certain position in the orbit at a fixed time interval, in order to keep the constellation synchronism, which is requested by the user\u27s antenna to have at switch-over time an isopower signal. To counteract the orbit perturbations (mainly due to lunisolar effects), that do not preserve the subtract longitude and synchronism, a low cost maneuvers strategy is proposed. These maneuvers are designed to control both the principal requirements (longitude and synchronism) by adjusting only the semimajor axis (in-plane maneuvers). Since perigee burns are more economical than apogee burns only the apogee radius is adjusted. The evolution of the orbit parameters with a typical sequence of maneuvers is examined including the effects of the moon, sun and a reduced (forth-order) Earth potential model. The effects of the atmospheric drag have not been taken into account due to the high perigee altitude. The maneuvers strategy proposed seems to be very promising in terms of delta-V. This result could yield a favorable opportunity in the use of small satellites for long duration missions (e.g. 5-7 years)

The Italian Approach to Small Satellites for Low Cost Access to Space Developments

Several technological institutions and scientific center are presently forbidden to access space exploration, because of the high costs involved with satellite development and launch. ITALSPAZIO has performed several studies directed toward the minimization of such costs. Possible design approaches are: use of a small bus capable to fly at marginal cost on expendable launch vehicles by paying delta-costs when passing from one launcher class to the upper next of the same launcher, (an example is constituted by the ARIANE IV when passing from AIRANE 40 to ARIANE 42s); use of left-over launcher capacities; use of subsystems and equipment’s developed for the two cases above, but using lower cost launcher

LEOSTAR: A Small Spacecraft for LEO Communication Missions

This paper outlines the major features of LEOSTAR, a small spacecraft able to support two way data message communications and position reporting missions with a multisatellite constellation. LEOSTAR is a three-axis gravity gradient stabilized satellite. A semi-passive control concept is envisaged with an extensible boom providing attitude stabilization together with three orthogonal Magnetic Torquers, an on-board dedicated computer and other devices. Thrusters provide the station keeping and transfer maneuvers according to an optimized strategy. A bipropellant system with monomethyhl hydrazine as propellant and nitrogen tetroxide as oxidizer is adopted. Large autonomy is envisaged through the adoption of an onboard system management processor. The communications\u27 payload power/mass range from 100 W/40 Kg to 200 W/60 Kg. A payload volume of 0.12 m3 and a maximum antenna dimension of 1 m. are allowed. LEOSTAR is designed to be compatible both with SCOUT and PEGASUS launchers in single or double launch configurations. It can also be launched by large vehicles such ARIANE 4 and Delta in cluster and/or piggy back modes

Os dramas históricos de Mendes Leal nos palcos do Rio de Janeiro: notas sobre as encenações e a recepção crítica

Tendo em vista a importante presença do repertório dramático do português José da Silva Mendes Leal (1818-1886) no teatro romântico brasileiro, este artigo tem por objetivo apresentar as encenações e a recepção crítica de suas peças nos palcos do Rio de Janeiro, entre as décadas de 1840 e 1850, reconstituídas por meio de informações recolhidas em fontes primárias, a saber: anúncios de espetáculos, críticas teatrais e comunicados de espectadores publicados pela imprensa fluminense

A Representação do Teatro nos Romances Franceses do Século XIX: realismo e efeitos dramáticos

This article analyzes the way theater, as an artistic and cultural activity, was represented in French novels published between the 1830’s and the 1860’s, such as The Red and the Black, by Stendhal, Lost Illusions, by Balzac, The Count of Monte Cristo, by Dumas (father), The Lady of the Camellias, by Dumas (son), and Madame Bovary, by Flaubert. Analyzing these novels, it was possible to conclude that the references to French theaters, plays, and playwrights emphasize realism and produce a dramatic effect on their characters and actions.Este artigo analisa o modo pelo qual o teatro, enquanto atividade artística e cultural, foi representado em romances franceses publicados entre as décadas de 1830 e 1860, tais como O Vermelho e o Negro, de Stendhal, Ilusões Perdidas, de Balzac, O Conde de Monte Cristo, de Dumas (pai), A Dama das Camélias, de Dumas (filho), e Madame Bovary, de Flaubert. A partir das análises, foi possível concluir que as referências às salas de espetáculos, peças e dramaturgos do teatro francês oitocentista conferem realismo e dramaticidade às personagens e às ações dos romances

Attention deficits predict phenotypic outcomes in syndrome-specific and domain-specific ways

Attentional difficulties, both at home and in the classroom, are reported across a number of neurodevelopmental disorders. However, exactly how attention influences early socio-cognitive learning remains unclear. We addressed this question both concurrently and longitudinally in a cross-syndrome design, with respect to the communicative domain of vocabulary and to the cognitive domain of early literacy, and then extended the analysis to social behavior. Participants were young children (aged 4–9 years at Time 1) with either Williams syndrome (WS, N = 26) or Down syndrome (DS, N = 26) and typically developing controls (N = 103). Children with WS displayed significantly greater attentional deficits (as indexed by teacher report of behavior typical of attention deficit hyperactivity disorder (ADHD) than children with DS, but both groups had greater attentional problems than the controls. Despite their attention differences, children with DS and those with WS were equivalent in their cognitive abilities of reading single words, both at Time 1 and 12 months later, at Time 2, although they differed in their early communicative abilities in terms of vocabulary. Greater ADHD-like behaviors predicted poorer subsequent literacy for children with DS, but not for children with WS, pointing to syndrome-specific attentional constraints on specific aspects of early development. Overall, our findings highlight the need to investigate more precisely whether and, if so, how, syndrome-specific profiles of behavioral difficulties constrain learning and socio-cognitive outcomes across different domains

Testing of the Nursing Evidence‐Based Practice Survey

BackgroundClinicians’ knowledge and skills for evidence‐based practice (EBP) and organizational climate are important for science‐based care. There is scant literature regarding aligning organizational culture with EBP implementation and even less for unit and organizational culture. The Nursing EBP Survey examines individual, unit, and organizational factors to better understand registered nurses’ (RN) self‐reported EBP.AimsEstablish and confirm factor loading, reliability, and discriminant validity for the untested Nursing EBP Survey.MethodsThe study employed a descriptive cross‐sectional survey design and was targeted for RNs. The setting included 14 hospitals and 680 medical offices in Southern California. The 1999 instrument consisted of 22 items; 7 items were added in 2005 for 29 items. The questionnaire used a 5 point, Likert‐type scale. The survey website opened in November 2016 and closed after 23 weeks. Psychometric testing and factor determination used parallel analysis, exploratory factor analysis, confirmatory factor analysis (CFA), and ANOVA post hoc comparisons.ResultsOne thousand one hundred and eighty‐one RNs completed the survey. All factor loadings in the CFA model were positive and significant (p < .001). All standardized loadings ranged from .70 to .94. The covariance estimate between Factor 1 and Factor 2 was marginally significant (p = .07). All other covariances and error variances were significant (p < .001). Final factor names were Practice Climate (Factor 1), Data Collection (Factor 2), Evidence Appraisal (Factor 3), Implementation (Factor 4), and Access to Evidence (Factor 5). Four of 5 factors showed significant differences between education levels (p < .05 level). All factors showed significant differences (p < .05) between inpatient and ambulatory staff, with higher scores for inpatient settings.Linking Evidence to ActionNurses’ knowledge, attitudes, and skills for EBP vary. The 2019 Nursing EBP survey offers RNs direction to plan and support improvement in evidence‐based outcomes and tailors future EBP initiatives.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154968/1/wvn12432.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154968/2/wvn12432_am.pd