32 research outputs found

    Towards a systemic approach to autonomic systems engineering

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    Captive reptile mortality rates in the home and implications for the wildlife trade

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    The trade in wildlife and keeping of exotic pets is subject to varying levels of national and international regulation and is a topic often attracting controversy. Reptiles are popular exotic pets and comprise a substantial component of the live animal trade. High mortality of traded animals raises welfare concerns, and also has implications for conservation if collection from the wild is required to meet demand. Mortality of reptiles can occur at any stage of the trade chain from collector to consumer. However, there is limited information on mortality rates of reptiles across trade chains, particularly amongst final consumers in the home. We investigated mortality rates of reptiles amongst consumers using a specialised technique for asking sensitive questions, additive Randomised Response Technique (aRRT), as well as direct questioning (DQ). Overall, 3.6% of snakes, chelonians and lizards died within one year of acquisition. Boas and pythons had the lowest reported mortality rates of 1.9% and chameleons had the highest at 28.2%. More than 97% of snakes, 87% of lizards and 69% of chelonians acquired by respondents over five years were reported to be captive bred and results suggest that mortality rates may be lowest for captive bred individuals. Estimates of mortality from aRRT and DQ did not differ significantly which is in line with our findings that respondents did not find questions about reptile mortality to be sensitive. This research suggests that captive reptile mortality in the home is rather low, and identifies those taxa where further effort could be made to reduce mortality rate

    The S phase checkpoint promotes the Smc5/6 complex dependent SUMOylation of Pol2, the catalytic subunit of DNA polymerase ε

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    Replication fork stalling and accumulation of single-stranded DNA trigger the S phase checkpoint, a signalling cascade that, in budding yeast, leads to the activation of the Rad53 kinase. Rad53 is essential in maintaining cell viability, but its targets of regulation are still partially unknown. Here we show that Rad53 drives the hyper-SUMOylation of Pol2, the catalytic subunit of DNA polymerase ε, principally following replication forks stalling induced by nucleotide depletion. Pol2 is the main target of SUMOylation within the replisome and its modification requires the SUMO-ligase Mms21, a subunit of the Smc5/6 complex. Moreover, the Smc5/6 complex co-purifies with Pol ε, independently of other replisome components. Finally, we map Pol2 SUMOylation to a single site within the N-terminal catalytic domain and identify a SUMO-interacting motif at the C-terminus of Pol2. These data suggest that the S phase checkpoint regulate Pol ε during replication stress through Pol2 SUMOylation and SUMO-binding abilit

    Some aspects of the winter ecology of juvenile salmonids with reference to possible habitat alteration by logging in Carnation Creek, Vancouver Island

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    Juvenile coho, steelhead, and cutthroat trout commonly spend from one to three or more years in coastal streams before migrating to the sea. Much of this time is spent in streams during the winter, making a study of these fishes' winter habitat requirements, distribution, behavior, and the possible influences of stream habitat alteration on them a useful undertaking. Some physical characteristics of areas selected by juvenile coho and steelhead were observed by snorkeling in a small west coast of Vancouver Island stream between September 1972 and April 1973. Observations revealed that with lowering water temperatures from 9°C to 2°C coho and older steelhead tended to move into deeper water while most steelhead fry remained in shallow, marginal sections of the stream. As water temperatures dropped in the winter, juvenile fish fed less and moved closer to areas offering low water velocities and cover. Steelhead fry were most often found under rubble while coho and older steelhead were most often found within upturned roots and under logs. Results from fish traps located on the lower ends of two small tributary streams indicated that juvenile coho, steelhead and cutthroat trout moved upstream into these tributaries in the late fall. Overwinter survival of coho in one tributary was 3-6 times as great as the estimated survival of coho in the main stream. Together the two tributaries contributed between 15 and 25 per cent to the total coho smolt production of the larger system. A series of experiments comparing coho and cutthroat preference for alternative habitat types in sidepool areas as may occur before and after stream disturbance were carried out during the winter. Both coho and cutthroat demonstrated a strong preference for bay areas offering overhanging bank cover as opposed to bays without cover, and for bays offering clean rubble substrate as opposed to silted rubble substrate. The impacts of timber harvesting on overwintering fish as suggested by the results from the underwater observations, winter movements, and the sidepool experiments are discussed and management recommendations are made.Forestry, Faculty ofGraduat
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