Behaviour of the smooth muscle of the cardiovascular system

This investigation was undertaken in an attempt to study the behaviour of vascular smooth muscle at the cellular level, and in conditions as near physiological as possible. Microelectrodes were inserted into smooth muscle cells in the walls of small arteries and arterioles in the rat mesenteric circulation in the intact anaesthetized rat, and the electrical activity recorded at rest and under the influence of various physiological stimuli.Intracellular recording gave membrane potentials that were low and variable, showing slow fluctuations at frequencies of some 9 to 12/min, and occasional action potentials which appeared to arise from the slow waves. Both these types of electrical activity were capable of being influenced by the sympathetic nervous system, as shown by the effects of stimulating the splanchnic nerves and denervating by chemical means and by cutting the nerves. However, as it is not known whether any residual nervous activity remained after denervation was attempted, it remains uncertain whether this electrical activity was generated by nervous activity or by some mechanism inherent in the smooth muscle cell itself.Propagated action potentials could not be elicited by direct electrical stimulation of the blood vessels, and the application of a stimulating pulse across the cell membrane into the interior of the cell did not evoke an action potential, but this may have been due to technical limitations.It was found impossible to record for long periods with an electrode inside a cell due to the small size and continuous movement of the cells, and the effects of various stimulating and inhibiting agents were therefore studied using extracellular recording methods. In general, stimulating agents such as asphyxia, electrical stimulation of the sympathetic nerves, and local application of adrenaline, noradrenaline, and vasopressin, increased the electrical activity of the muscle, and inhibiting agents such as acetylcholine and removal of the nerve supply depressed it. High concentrations of adrenaline and noradrenaline appeared to be capable of causing the muscle cells to contract without firing action potentials, but whether this type of contracture is a Use other side if necessary. physiological phenomenon remains uncertain. None of these manoeuvres had any significant effect on the frequency of the slow waves, but under the influence of stimulating agents the percentage of waves with action potentials increased, and spikes appeared in twos and threes.It was concluded that the technical difficulties due to the small size of the smooth muscle cells relative to that of the penetrating electrode tip will limit further investigation using refined techniques until the development of methods for producing finer microelectrodes

Defining Short-Term Accommodation for Animals

Abstract The terms short-term, temporary, and transitional are related but can have different contexts and meanings for animal husbandry. The definitions and use of these terms can be pivotal to animal housing and welfare. We conducted three separate literature searches using Google Scholar for relevant reports regarding short-term, temporary, or transitional animal husbandry, and analysed key publications that stipulate relevant periods of accommodation. English Government guidance regarding acceptable short-term, temporary, or transitional accommodation for animals varies widely from 24 h, all animals at all facilities should be accommodated in conditions that are consistent with long-term housing, husbandry, and best practices

Automatic Transcription of Polyphonic Vocal Music

This paper presents a method for automatic music transcription applied to audio recordings of a cappella performances with multiple singers. We propose a system for multi-pitch detection and voice assignment that integrates an acoustic and a music language model. The acoustic model performs spectrogram decomposition, extending probabilistic latent component analysis (PLCA) using a six-dimensional dictionary with pre-extracted log-spectral templates. The music language model performs voice separation and assignment using hidden Markov models that apply musicological assumptions. By integrating the two models, the system is able to detect multiple concurrent pitches in polyphonic vocal music and assign each detected pitch to a specific voice type such as soprano, alto, tenor or bass (SATB). We compare our system against multiple baselines, achieving state-of-the-art results for both multi-pitch detection and voice assignment on a dataset of Bach chorales and another of barbershop quartets. We also present an additional evaluation of our system using varied pitch tolerance levels to investigate its performance at 20-cent pitch resolution

Pathways to economic well-being among teenage mothers in Great Britain

The present study examines pathways to independence from social welfare among 738 teenage mothers, participants of the 1970 British Cohort Study, who were followed up at age 30 years. Using a longitudinal design, a pathway model is tested, examining linkages between family social background, cognitive ability, school motivation, and individual investments in education, as well as work- and family-related roles. The most important factors associated with financial independence by age 30 are continued attachment to the labor market as well as a stable relationship with a partner (not necessarily the father of the child). Pathways to financial independence, in turn, are predicted through own cognitive resources, school motivation, and family cohesion. Implications of findings for policy making are discussed.© 2010 Hogrefe Publishing

‘Stick that knife in me’: Shane Meadows’ children

This article brings Shane Meadows’ Dead Man's Shoes (2004) into dialogue with the history of the depiction of the child on film. Exploring Meadows’ work for its complex investment in the figure of the child on screen, it traces the limits of the liberal ideology of the child in his cinema and the structures of feeling mobilised by its uses – at once aesthetic and sociological – of technologies of vision