3 resultados para Fine tuning
em Nottingham eTheses
Resumo:
Starting in December 1982 the University of Nottingham decided to phototypeset almost all of its examination papers `in house' using the troff, tbl and eqn programs running under UNIX. This tutorial lecture highlights the features of the three programs with particular reference to their strengths and weaknesses in a production environment. The following issues are particularly addressed: Standards -- all three software packages require the embedding of commands and the invocation of pre-written macros, rather than `what you see is what you get'. This can help to enforce standards, in the absence of traditional compositor skills. Hardware and Software -- the requirements are analysed for an inexpensive preview facility and a low-level interface to the phototypesetter. Mathematical and Technical papers -- the fine-tuning of eqn to impose a standard house style. Staff skills and training -- systems of this kind do not require the operators to have had previous experience of phototypesetting. Of much greater importance is willingness and flexibility in learning how to use computer systems.
Resumo:
Gating of sensory (e.g. auditory) information has been demonstrated as a reduction in the auditory-evoked potential responses recorded in the brain of both normal animals and human subjects. Auditory gating is perturbed in schizophrenic patients and pharmacologically by drugs such as amphetamine, phencyclidine or ketamine, which precipitate schizophrenic-like symptoms in normal subjects. The neurobiological basis underlying this sensory gating can be investigated using local field potential recordings from single electrodes. In this paper we use such technology to investigate the role of cannabinoids in sensory gating. Cannabinoids represent a fundamentally new class of retrograde messengers which are released postsynaptically and bind to presynaptic receptors. In this way they allow fine-tuning of neuronal response, and in particular can lead to so-called depolarization-induced suppression of inhibition (DSI). Our experimental results show that application of the exogenous cannabinoid WIN55, 212-2 can abolish sensory gating as measured by the amplitude of local field responses in rat hippocampal region CA3. Importantly we develop a simple firing rate population model of CA3 and show that gating is heavily dependent upon the presence of a slow inhibitory (GABAB) pathway. Moreover, a simple phenomenological model of cannabinoid dynamics underlying DSI is shown to abolish gating in a manner consistent with our experimental findings.
Resumo:
The paper reports some of the findings of an exploratory study which looks at foster fathers’ experiences of fostering and discusses their routes into foster care and their perspectives on their roles and tasks. The study collected quantitative and qualitative data by approaching all foster fathers registered with a single independent fostering agency based in southeast England. They were asked about their personal and professional attributes, and their experiences of and views concerning the role of foster father. The study discusses the foster fathers’ motivation to foster, and argues that what they see as its positives and drawbacks, and how it fits into their own family lives, are all relevant to improving service recruitment, delivery and retention. The study produced some evidence about the distinctive and positive contribution which foster fathers see themselves making to the lives of the children they foster. Further research is needed to refine our knowledge of what this contribution may be. Such knowledge could potentially develop our understanding of the roles of fathers in child development more generally as well as fine-tuning practice in matching what particular placements have to offer to the needs of individual children.