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Survival Thresholds (survival + threshold)
Selected AbstractsIncreasing ocean temperatures allow tropical fishes to survive overwinter in temperate watersGLOBAL CHANGE BIOLOGY, Issue 2 2010WILL F. FIGUEIRA Abstract The southeast coast of Australia is a global hotspot for increasing ocean temperatures due to climate change. The temperate incursion of the East Australian Current (EAC) is increasing, affording increased connectivity with the Great Barrier Reef. The survival of tropically sourced juveniles over the winter is a significant stumbling block to poleward range shifts of marine organisms in this region. Here we examine the dependence of overwintering on winter severity and prewinter recruitment for eight species of juvenile coral reef fishes which are carried into temperate SE Australia (30,37 °S) by the EAC during the austral summer. The probability of persistence was most strongly influenced by average winter temperature and there was no effect of recruitment strength. Long-term (138 years) data indicate that winter water temperatures throughout this region are increasing at a rate above the global average and predictions indicate a further warming of >2 °C by the end of the century. Rising ocean temperatures are resulting in a higher frequency of winter temperatures above survival thresholds. Current warming trajectories predict 100% of winters will be survivable by at least five of the study species as far south as Sydney (34 °S) by 2080. The implications for range expansions of these and other species of coral reef fish are discussed. [source] SEDIMENTARY IMPRINT OF MICROCYSTIS AERUGINOSA (CYANOBACTERIA) BLOOMS IN GRANGENT RESERVOIR (LOIRE, FRANCE),JOURNAL OF PHYCOLOGY, Issue 3 2007Delphine Latour Analysis of a sediment core taken from the Grangent reservoir in 2004 showed the presence of high concentrations of Microcystis aeruginosa Kütz. colonies at the sediment surface (250 colonies,ˇ,mL sediment,1) and also at depths of 25,35 cm (2300 coloniesˇmL sediment,1) and 70 cm (600 colonies,ˇ,mL sediment,1). Measurements of radioactive isotopes (7Be, 137Cs, and 241Am) along with photographic analysis of the core were used to date the deep layers: the layer located at ,30 cm dates from summer 2003, and that located at ,70 cm from 1990 to 1991. The physiological and morphological conditions of those benthic colonies were compared with those of planktonic colonies using several techniques (environmental scanning electron microscopy [ESEM], TEM, DNA markers, cellular esterases, and toxins). The ESEM observations showed that, as these colonies age, peripheral cells disappear, with no cells remaining in the mucilage of the deepest colonies (70 cm), an indication of the survival thresholds of these organisms. In the benthic phase, the physiological conditions (enzyme activity, cell division, and intracellular toxins) and ultrastructure (particularly the gas vesicles) of the cells surviving in the heart of the colony are comparable to those of the planktonic form, with all the potential needed for growth. Maintaining cellular integrity requires a process that can provide sufficient energy and is expressed in the reduced, but still existing, enzymatic activity that we measured, which is equivalent to a quiescent state. [source] Retransplantation for recurrent hepatitis C: Positive aspectsLIVER TRANSPLANTATION, Issue 11 2003Timothy M. McCashland Key points 1. The prevalence of retransplantation for hepatitis C (HCV) patients is stable (around 40%). 2. Survival models to predict outcome of retransplantation do not show that HCV is an independent variable with poor outcomes. 3. Using Model for End-Stage Liver Disease (MELD) scores from the United Network for Organ Sharing (UNOS) database from 1996-2002, retransplantation for HCV had similar outcomes to other causes of retransplantation. 4. Poorer outcomes were noted for retransplantation with MELD scores greater than 25. 5. Minimal survival thresholds need to be developed for retransplantation for all causes of retransplantation. [source] Adult living donor liver transplantation: Preferences about donation outside the medical communityLIVER TRANSPLANTATION, Issue 4 2001Scott J. Cotler MD An increasing number of transplant centers are performing adult living donor liver transplantation (LDLT). We evaluated peoples' perspectives on possible outcomes of living donation, thresholds for donating, and views regarding the donation process. One hundred fifty people were surveyed; half were from a medical care group serving an indigent population and half were from a private clinic. Preferences about outcomes of adult living donation were ranked and quantified on a visual analogue scale. Thresholds for donation to a loved one were quantified. Sixty percent of the respondents suggested they would prefer to donate and die and have the transplant recipient live rather than forgo donation and have the potential transplant recipient die of liver failure. Participants' stated threshold for living donation was a median survival for themselves of only 79%. They would require that their loved one have a median survival of 55% with transplantation before they would agree to donate. Respondents from the medical care group reported higher survival thresholds for themselves and the transplant recipient, and race was the most statistically significant predictor of those thresholds. Sex was more predictive of threshold probabilities from the private clinic. Eighty-one percent of the respondents believed that the potential donor, not a physician, should have the final say regarding candidacy for living donation. In conclusion, the findings of this survey support the use of adult LDLT. Most respondents were willing to accept mortality rates that far exceed the estimated risk of donation and favored outcomes in which a loved one was saved. [source] | ||||||||||