The ATS-6 power system: Hardware implementation and orbital performance

The Applications Technology Satellite-6 power system, a shunt-boost configuration, uses partial shunt regulation of the solar array and a boost regulator for control of battery power. Regulation is provided for three different operating modes: shunt, charge, and boost. This configuration achieves the highest efficiency of power transfer from the solar array to the loads. The excellent dynamic regulation and low output impedance of the power system virtually eliminated the problem of subsystem interactions on the power bus due to conducted interference from load current fluctuations. The performance of the power system continues to be excellent. The solar array degradation (18.5 percent) was less than the specified 20 percent in two years in spite of extreme cycling from -160 C to 60 C. A unique battery cycling regime of discharges varying from 5 percent to 60 percent daily is being encountered. During the second year, noneclipse discharges have occurred twice a day to depths of 35 percent and 45 percent. Battery performance was good with only a small decrease in end-of-discharge voltage. A recent test to evaluate capacity gave 12.4 AH (83% of the nominal capacity of 15 AH) after over 1400 battery discharge cycles. A small increase in the end-of-charge voltage has recently occurred necessitating a change in the charge regime to achieve full charge conditions

Satellite Servicing in the Space Station Era

Repair and serv1c1ng of orbiting satellites in the Space Station era will realize significant enhancements to the capabilities available to date. The first on-orbit repair of an orbiting satellite was demonstrated in 1972 on the Skylab mission using makeshift tools, procedures, and Extravehicular Activity (EVA) techniques. Subsequently, in 1984, the repair and resultant extension of the Solar Maximum Mission (SMM) took full advantage of the spacecraft\u27s having been designed at the outset to be repaired and modified on orbit. Although this mission, among others performed by the Space Transportation System (STS) (Westar 6, Palapa 8-2, and Leasat F3), testified to the fact that much progress had been made in the on-orbit repair and servicing of satellites, it also served to highlight the areas in which considerable improvement and technology development were needed. The Space Station capabilities for on-orbit servicing will serve to provide these improvements and technology advances. By expanding on the servicing experience and capabilities provided directly by the STS, the Space Station will significantly enhance mission objectives of long-duration scientific missions, not only by repair and consumable replenishment, but also by the addition and replacement of scientfic instruments with upgraded versions. Major observatory missions such as the Hubble Space Telescope (HST), the Gamma Ray Observatory (GRO), and the Advanced X-ray Astronomical Facility (AXAF) will be among the beneficiaries of this new, enhanced capability. This paper will describe the satellite servicing capabilities planned for the Space Station

Revisión de diferentes enfoques de evaluación y tratamiento de los problemas de comportamiento

El presente documento se centra en disminuir conductas que, quizás, es algo más complejo ya que los profesionales deben adquirir mayor responsabilidad debido a las técnicas que se pueden utilizar. Dirigido a maestros, ayudantes, personal institucional, diseñadores de programas, miembros de los comités de manejo conductual o comités de procedimientos restrictivos. Se centra en personas con retraso mental severo y profundo ya que hay menos textos disponibles para tratarles que con niveles más altos de discapacidad. Los procedimientos se presentan de acuerdo con el Modelo de Tratamiento Menos Restrictivo que se ha desarrollado para proteger las libertades civiles de las personas con retraso en el desarrollo

A tetracationic porphyrin with dual anti-prion activity

Prions are deadly infectious agents made of PrPSc, a misfolded variant of the cellular prion protein (PrPC) which self-propagates by inducing misfolding of native PrPC. PrPSc can adopt different pathogenic conformations (prion strains), which can be resistant to potential drugs, or acquire drug resistance, hampering the development of effective therapies. We identified Zn(II)-BnPyP, a tetracationic porphyrin that binds to distinct domains of native PrPC, eliciting a dual anti-prion effect. Zn(II)-BnPyP binding to a C-terminal pocket destabilizes the native PrPC fold, hindering conversion to PrPSc; Zn(II)-BnPyP binding to the flexible N-terminal tail disrupts N- to C-terminal interactions, triggering PrPC endocytosis and lysosomal degradation, thus reducing the substrate for PrPSc generation. Zn(II)-BnPyP inhibits propagation of different prion strains in vitro, in neuronal cells and organotypic brain cultures. These results identify a PrPC-targeting compound with an unprecedented dual mechanism of action which might be exploited to achieve anti-prion effects without engendering drug resistance

How service‐users with intellectual disabilities understand challenging behaviour and approaches to managing it

Background This study explored understandings that service‐users with intellectual disabilities and challenging behaviour held around their behaviour, what shaped these understandings, and the relationship between how behaviours are managed and well‐being. Methods Eight participants (three female, five male) partook in individual semi‐structured qualitative interviews. Interviews were transcribed and analysed using interpretative phenomenological analysis. Results Three master themes emerged from this analysis: (a) challenging behaviour can be explained via an internal or external frame of reference, with each framework having different implications for how participants attempted to manage behaviour. (b) Positive relationships provide a long‐term buffer to challenging behaviour, with positive relationships with family, staff and peers operating through different mechanisms to achieve this. (c) A greater ability to exert power and control in day‐to‐day life was perceived to reduce challenging behaviour in the long term. Conclusions Implications for practice are discussed

The effect of culture on Corporate Governance Practices in Nigeria

This study focuses on the effect of culture on the application of corporate governance practices in Nigeria. Corporate governance has been receiving serious attention in emerging markets over the past two decades. But relatively little attention has been given to the study on corporate governance in a country study. The current situations in Nigerian public and private sectors such as the corporate scandal resulting from Lever Brothers Nigeria plc, Siemens, Shell, Halliburton, and Cadbury Nigeria plc, have shown that the issue of fraud, corruption, and corporate scandals cannot be overlooked. Most top management, as this study argues, bring in beliefs acquired from their early childhood into their senior management roles and responsibilities. This study adopts a grounded theory and reports on the effect of culture on the implementation of corporate governance in Nigeria. Based on the interview with 32 staffs, this study identifies the effect of culture that shapes corporate governance and they include abuse of power by top management, weak legal framework, poor recruitment and ineffective control. Although having efficient corporate governance is worth pursuing, this depends on the power of top management, the strength of internal control procedures and the legal framework put in place by management

Prevalence of the extinction burst and its attenuation during treatment

Although extinction has been an effective treatment for a variety of behavior disorders, its use may be associated with several adverse side effects, the most common being an initial increase in the frequency of the target response, called an “extinction burst.” We attempted to determine the prevalence of the extinction burst in applied research and its possible attenuation with other operant procedures. An analysis of 113 sets of extinction data indicated that bursting may not be as common as previously assumed (it occurred in 24% of the cases) and may be less likely when extinction is implemented with alternative procedures rather than as the sole intervention (bursting was evident in 12% of the former cases and 36% of the latter)

Epidemiological studies related to cercarial dermatitis in lakes of the Savoy district (France)

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