Behavioural and physiological adaptations to low-temperature environments in the common frog, Rana temporaria

<b>Background</b><p></p> Extreme environments can impose strong ecological and evolutionary pressures at a local level. Ectotherms are particularly sensitive to low-temperature environments, which can result in a reduced activity period, slowed physiological processes and increased exposure to sub-zero temperatures. The aim of this study was to assess the behavioural and physiological responses that facilitate survival in low-temperature environments. In particular, we asked: 1) do high-altitude common frog (Rana temporaria) adults extend the time available for larval growth by breeding at lower temperatures than low-altitude individuals?; and 2) do tadpoles sampled from high-altitude sites differ physiologically from those from low-altitude sites, in terms of routine metabolic rate (RMR) and freeze tolerance? Breeding date was assessed as the first day of spawn observation and local temperature recorded for five, paired high- and low-altitude R. temporaria breeding sites in Scotland. Spawn was collected and tadpoles raised in a common laboratory environment, where RMR was measured as oxygen consumed using a closed respiratory tube system. Freeze tolerance was measured as survival following slow cooling to the point when all container water had frozen.<p></p> <b>Results</b><p></p> We found that breeding did not occur below 5°C at any site and there was no significant relationship between breeding temperature and altitude, leading to a delay in spawning of five days for every 100 m increase in altitude. The relationship between altitude and RMR varied by mountain but was lower for individuals sampled from high- than low-altitude sites within the three mountains with the highest high-altitude sites (≥900 m). In contrast, individuals sampled from low-altitudes survived freezing significantly better than those from high-altitudes, across all mountains.<p></p> <b>Conclusions</b><p></p> Our results suggest that adults at high-altitude do not show behavioural adaptations in terms of breeding at lower temperatures. However, tadpoles appear to have the potential to adapt physiologically to surviving at high-altitude via reduced RMR but without an increase in freeze tolerance. Therefore, survival at high-altitude may be facilitated by physiological mechanisms that permit faster growth rates, allowing completion of larval development within a shorter time period, alleviating the need for adaptations that extend the time available for larval growth

Cell Therapy for Type 1 Diabetes

Acknowledgements The work described in this review was supported by a grant from the MRC. K.R.M. is supported by a fellowship from the Scottish Translational Medicines and Therapeutics Initiative through the Wellcome Trust.Peer reviewedPublisher PD

Economic Policy And Wildlife Management In Zimbabwe

An AEE Draft Paper Prepared for AFTEN, World Bank conference detailing Zimbabwe's Economic Policy and Wildlife Management..Wildlife is beginning to make a significant contribution to Zimbabwe's national economy and it would appear that tourism in general but particularly wildlife-based tourism is the fastest growing sector in the economy. The impacts of this development are far-reaching and will affect land-use systems in the state, private farming and communal sectors. There has been much interest in this wildlife development with emphasis placed on its potential role as a more sustainable land-use system than conventional agriculture in semi-arid zones and its potential to contribute to rural development.The World Bank

Labor Law - NLRA - Roving Situs Picketing as Violation of Section 8(b)(4)(A)

Respondent union sought to organize the crane and dragline operators of a manufacturer of ready-mixed cement and posted pickets about the local manufacturing plant. During the working day each of the employer\u27s delivery trucks crossed the picket line at least twice. In addition, the union established a roving picket line which circulated about the manufacturer\u27s trucks while they were making deliveries to customers at local construction sites. The roving picketing lasted only so long as the workers of the primary employer remained on the customer\u27s premises. The pickets at all times stayed within six hundred feet of the trucks. The legend on their picket signs was explicit in stating that the dispute was only with the primary employer, and the picketers distributed handbills which set out with accuracy the nature of the strike. The regional director of the NLRB sought an injunction under section 10 (f), alleging a violation of section 8 (b) (4) (A), which proscribes secondary picketing. He adduced evidence to show that seven of the primary employer\u27s customers had ceased their purchases of cement from the manufacturer after the picketing had begun. Moreover, the union had made requests to customers to buy cement from other sources during the strike. Held, injunction granted. There were reasonable grounds for finding that one objective of the picketing was the encouragement of the neutral employees at the site to cease their work so long as the primary employer transacted business on the premises. Le Bus v. Locals 406, 406A, 406B and 406G, International Union of Operating Engineers, (E.D. La. 1956) 145 F. Supp. 316

Some aspects of education in South Africa

African Studies Seminar series. Paper presented December, 1968Since the time of Athens and Sparta, it has been argued that the future of any state depends very much on the amount of interest and energy that is devoted to education in the state. It is now realised that finance must also be added to this list. Despite the fact that this realisation has a long history, there are few educationists in any country in the world who are satisfied with the amounts of interest, energy and finance which are devoted to education. South Africa is no exception. In this series of papers, stress will be laid on education for Non-White peoples for two reasons. The first is that less is known about their problems. The second is that if South Africa is to continue to prosper, much will depend upon the products of the country's Non-White schools. The aim in this introductory paper will be to show how great this dependence is already, and how it is likely to increase in the future. Material will be taken from a recently published report on "Education and the South African Economy", (1) as this brings together in one volume much new material. The central theme of this report can be expressed in this way: "Over the past thirty-five years the rate of economic growth in South Africa has been remarkably steady, apart from normal cyclical fluctuations, at an average of 4 1/2 per cent per annum, after allowing for the falling purchasing power of money". (2

Effects of magnesium treatment in a model of internal capsule lesion in spontaneously hypertensive rats

<p><b>Background and Purpose:</b> The study aim was to assess the effects of magnesium sulfate (MgSO4) administration on white matter damage in vivo in spontaneously hypertensive rats.</p> <p><b>Methods:</b> The left internal capsule was lesioned by a local injection of endothelin-1 (ET-1; 200 pmol) in adult spontaneously hypertensive rats. MgSO4 was administered (300 mg/kg SC) 30 minutes before injection of ET-1, plus 200 mg/kg every hour thereafter for 4 hours. Infarct size was measured by T2-weighted magnetic resonance imaging (day 2) and histology (day 11), and functional recovery was assessed on days 3 and 10 by the cylinder and walking-ladder tests.</p> <p><b>Results:</b> ET-1 application induced a small, localized lesion within the internal capsule. Despite reducing blood pressure, MgSO4 did not significantly influence infarct volume (by magnetic resonance imaging: median, 2.1 mm3; interquartile range, 1.3 to 3.8, vs 1.6 mm3 and 1.2 to 2.1, for the vehicle-treated group; by histology: 0.3 mm3 and 0.2 to 0.9 vs 0.3 mm3 and 0.2 to 0.5, respectively). Significant forelimb and hindlimb motor deficits were evident in the vehicle-treated group as late as day 10. These impairments were significantly ameliorated by MgSO4 in both cylinder (left forelimb use, P<0.01 and both-forelimb use, P<0.03 vs vehicle) and walking-ladder (right hindlimb score, P<0.02 vs vehicle) tests.</p> <p><b>Conclusions:</b> ET-1–induced internal capsule ischemia in spontaneously hypertensive rats represents a good model of lacunar infarct with small lesion size, minimal adverse effects, and a measurable motor deficit. Despite inducing mild hypotension, MgSO4 did not significantly influence infarct size but reduced motor deficits, supporting its potential utility for the treatment of lacunar infarct.</p&gt

Visual perception of content-prioritised sign language video quality.

Video communication systems currently provide poor quality and performance for deaf people using sign language, particularly at low bit rates. Our previous work, involving eye movement tracking experiments and analysis of visual attention mechanisms for sign language, demonstrated a consistent characteristic response which could be exploited to enable optimisation of video coding systems performance by prioritising content for deaf users. This paper describes an experiment designed to test the perceived quality of selectively prioritised video for sign language communication. A series of selectively degraded video clips was shown to individual deaf viewers. Participants subjectively rated the quality of the modified video on a Degradation Category Rating (DCR) scale adapted for sign language users. The results demonstrate the potential to develop content-prioritised coding schemes, based on viewing behaviour, which can reduce bandwidth requirements and provide best quality for the needs of the user. We propose selective quantisation to reduce compression in visually important regions of video images, which require spatial detail for small slow motion detection, and increased compression of regions regarded in peripheral vision where large rapid movements occur in sign language communication

Billy Elliot The Musical: visual representations of working-class masculinity and the all-singing, all-dancing bo[d]y

According to Cynthia Weber, ‘[d]ance is commonly thought of as liberating, transformative, empowering, transgressive, and even as dangerous’. Yet ballet as a masculine activity still remains a suspect phenomenon. This paper will challenge this claim in relation to Billy Elliot the Musical and its critical reception. The transformation of the visual representation of the human body on stage (from an ephemeral existence to a timeless work of art) will be discussed and analysed vis-a-vis the text and sub-texts of Stephen Daldry’s direction and Peter Darling’s choreography. The dynamics of working-class masculinity will be contextualised within the framework of the family, the older female, the community, the self and the act of dancing itself