15,027 research outputs found
VHF command system study
Solutions are provided to specific problems arising in the GSFC VHF-PSK and VHF-FSK Command Systems in support of establishment and maintenance of Data Systems Standards. Signal structures which incorporate transmission on the uplink of a clock along with the PSK or FSK data are considered. Strategies are developed for allocating power between the clock and data, and spectral analyses are performed. Bit error probability and other probabilities pertinent to correct transmission of command messages are calculated. Biphase PCM/PM and PCM/FM are considered as candidate modulation techniques on the telemetry downlink, with application to command verification. Comparative performance of PCM/PM and PSK systems is given special attention, including implementation considerations. Gain in bit error performance due to coding is also considered
A comparison of the radiation tolerance characteristics of multijunction solar cells with series and voltage-matched configurations
The effect of series and voltage-matched configurations on the performance of multijunction solar cells in a radiation environment was investigated. It was found that the configuration of the multijunction solar cell can have a significant impact on its radiation tolerence characteristics
Project Technical Report MSC/TRW Task KM-205 - SLP OWS Control System Digital Simulation Requirements
Digital simulation of AAP orbital workshop pointing control system and thrust attitude control system
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Realising the therapeutic potential of neuroactive steroid modulators of the GABA<sub>A</sub> receptor
In the 1980s particular endogenous metabolites of progesterone and of deoxycorticosterone were revealed to be potent, efficacious, positive allosteric modulators (PAMs) of the GABAA receptor (GABAAR). These reports were followed by the discovery that such steroids may be synthesised not only in peripheral endocrine glands, but locally in the central nervous system (CNS), to potentially act as paracrine, or autocrine "neurosteroid" messengers, thereby fine tuning neuronal inhibition. These discoveries triggered enthusiasm to elucidate the physiological role of such neurosteroids and explore whether their levels may be perturbed in particular psychiatric and neurological disorders. In preclinical studies the GABAAR-active steroids were shown to exhibit anxiolytic, anticonvulsant, analgesic and sedative properties and at relatively high doses to induce a state of general anaesthesia. Collectively, these findings encouraged efforts to investigate the therapeutic potential of neurosteroids and related synthetic analogues. However, following over 30 years of investigation, realising their possible medical potential has proved challenging. The recent FDA approval for the natural neurosteroid allopregnanolone (brexanolone) to treat postpartum depression (PPD) should trigger renewed enthusiasm for neurosteroid research. Here we focus on the influence of neuroactive steroids on GABA-ergic signalling and on the challenges faced in developing such steroids as anaesthetics, sedatives, analgesics, anticonvulsants, antidepressants and as treatments for neurodegenerative disorders
Saying the ‘F word … in the nicest possible way’: augmentative communication and discourses of disability
This paper examines a case study of a severely physically disabled man, Ralph, in terms of his interaction with his carers. He communicates using various systems of augmentative and alternative communication (AAC, such as symbol boards and high-tech devices), the vocabulary for which has mostly been selected for him by others. The starting point of the paper is the assumption that disabled people have traditionally held a disempowered position in society (relative to non-disabled people), and the question asked is to what extent is Ralph further disempowered by the limited vocabulary available to him in his AAC systems, and in the way others interact with him. The paper draws on the work of Bourdieu, according to whom ‘Language is not only an instrument of communication or even of knowledge, but also an instrument of power’ (1977, 648). I consider the tensions between the drive towards the empowerment of disabled individuals, as exemplified by the provision of AAC, and opposition to allowing access to certain types of vocabulary (especially expletives such as ‘the F word’), unless it is expressed in ‘the nicest possible way’
The Effects of Critical Thinking Skills Training on Student Performance in an Educational Psychology Class
Critical thinking skills have become an important part of current educational practices. However, there is little empirical evidence comparing the effectiveness of the programs teaching these skills. In addition, there are questions as to whether the skills should be taught within the class content or separate from the class content.
This study assigned students attending labs as part of an educational psychology class to two experimental conditions (content-based and content-free) and a control condition. Measures were scores on lab papers and test scores for the class. In addition, an attitude survey was used to assess student attitudes to each condition, and the overall quality of the labs was assessed. An analysis of variance was performed on the data. Results indicated little difference between experimental and control conditions
Illinois Tool Works v. Independent Ink: Inking Out Limits of the Patent Grant
This Note argues that, in deciding Independent Ink, the Supreme Court was overbroad in its characterization of the market power presumption, and the Court\u27s analysis neglected important policies justifying the United States patent system
A Model Developmental Child-Sensitive Curriculum For Japanese Preschool Aged Children
The purpose of this study was to design and develop a model preschool/kindergarten curriculum program that merges the best practices of representative American and Japanese programs. To accomplish this purpose, a review of current literature related to early child development was conducted, as well as a review of research supporting developmentally appropriate, early childhood curriculum programs. Additionally, information and materials from selected model American early childhood centers was contrasted with a representative preschool program sample from Japan
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