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Original Population (original + population)
Selected AbstractsParasites lost , do invaders miss the boat or drown on arrival?ECOLOGY LETTERS, Issue 4 2010Catriona J. MacLeod Ecology Letters (2010) 13: 516,527 Abstract Host species that colonize new regions often lose parasite species. Using population arrival and establishment data for New Zealand's introduced bird species and their ectoparasitic chewing lice species, we test the relative importance of different processes and mechanisms in causing parasite species loss. Few lice failed to arrive in New Zealand with their hosts due to being missed by chance in the sample of hosts from the original population (missing the boat). Rather, most lice were absent because their hosts or the parasite themselves failed to establish populations in their new environment. Given they arrived and their host established, parasite persistence was more strongly related to factors associated with transmission efficiency (number of host individuals introduced, host body size, host sociality and parasite suborder) than parasite propagule pressure and aggregation. Such insights into parasite success are invaluable to both understanding and managing their impact. [source] Menstrual age,dependent systematic error in sonographic fetal weight estimation: A mathematical modelJOURNAL OF CLINICAL ULTRASOUND, Issue 3 2002Max Mongelli MD Abstract Purpose We used computer modeling techniques to evaluate the accuracy of different types of sonographic formulas for estimating fetal weight across the full range of clinically important menstrual ages. Methods Input data for the computer modeling techniques were derived from published British standards for normal distributions of sonographic biometric growth parameters and their correlation coefficients; these standards had been derived from fetal populations whose ages were determined using sonography. The accuracy of each of 10 formulas for estimating fetal weight was calculated by comparing the weight estimates obtained with these formulas in simulated populations with the weight estimates expected from birth weight data, from 24 weeks' menstrual age to term. Preterm weights were estimated by interpolation from term birth weights using sonographic growth curves. With an ideal formula, the median weight estimates at term should not differ from the population birth weight median. Results The simulated output sonographic values closely matched those of the original population. The accuracy of the fetal weight estimation differed by menstrual age and between various formulas. Most methods tended to overestimate fetal weight at term. Shepard's formula progressively overestimated weights from about 2% at 32 weeks to more than 15% at term. The accuracy of Combs's and Shinozuka's volumetric formulas varied least by menstrual age. Hadlock's formula underestimated preterm fetal weight by up to 7% and overestimated fetal weight at term by up to 5%. Conclusions The accuracy of sonographic fetal weight estimation based on volumetric formulas is more consistent across menstrual ages than are other methods. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:139,144, 2002; DOI 10.1002/jcu.10051 [source] The growth,mortality relationship in larval cohorts of Sardinops melanostictus, revealed by using two new approaches to analyse longitudinal data from otolithsJOURNAL OF FISH BIOLOGY, Issue 7 2008G. Plaza The growth,mortality relationship was assessed for larval cohorts of the Japanese sardine Sardinops melanostictus using two new approaches: (1) repeat measures in general linear model (RM-GLMs) and (2) the autoregressive-individual method (AIM). Both methods were compared to the traditional approach in which repeat-measure ANOVA was used to compare the changes in increment width (WI) at age and otolith radii (RO) at age between individuals from an original population and survivors. In RM-GLMs, both the WI at age and RO at age (i.e. at 5, 10, 15 and 20 days) were used as the dependent variables, and the standardized residuals of both regressions RO and age and RO and total length (LT), age class, and day of the year as independent variables. A significant increase in WI at age and RO at age from younger to older age classes was seen as indicative of growth-dependent selection. In AIM, the RO -at-age relationship for each fish was fitted for the first 20 days, using autoregression, and then the growth traits (i.e. slopes) between the original cohorts and survivors were compared using ANOVA. In the traditional approach, the WI at age and RO at age for the first 20 days of an original population were compared with those of survivors sampled in later stages. GLMs and traditional approaches supported the growth rate (i.e. the faster an individual grows, the higher its probability of survival) and bigger is better (i.e. larger individuals at any given age will have lower probability of mortality than smaller individuals of the same age) mechanisms. Furthermore, AIM showed that individuals from original cohorts had lower otolith growth rates than those from survivors, giving further support for the growth,mortality hypothesis for the larval stage of this clupeid. [source] Otolith-based analysis of survival and size-selective mortality of stocked 0+ year pike related to time of stockingJOURNAL OF FISH BIOLOGY, Issue 6 2004P. Grønkjær The effect of time of stocking on the extent and source of mortality in 0+ year pike Esox lucius was investigated in a lake (20 ha) and a drainable pond (0·5 ha) using pike with alizarin marked otoliths. The results indicated that pike stocked late relative to the recruitment of native 0+ year pike fell victim to cannibalism from these larger individuals. This resulted in very low survival through the first growing season (<2%). Pike stocked early in the season exhibited significantly higher survival (>12%). Analyses of the size distribution of the alizarin marks from these fish revealed that the largest 0+ year pike exhibited by a factor of 3·3, higher survival than the average 0+ year pike in the lake. In order for large 0+ year pike to exhibit such high relative fitness a minimum of 69·7% of the original population must suffer size dependent mortality. In the pond the survival of the largest pike was by a factor of 4·2 higher than the average pike, and the corresponding size dependent mortality was 76·4%. The substantial size-dependent mortality was most probably due to intra-cohort cannibalism or habitat segregation between large and small 0+ year pike that exposes the small pike to predatory fishes in the open lake. Cannibalism exerts a major influence on the survival of 0+ year pike post-stocking although the magnitude and origin differ in relation to stocking time. [source] Solar Radiation-induced Mortality of Marine Pico-phytoplankton in the Oligotrophic Ocean,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Susana Agustí ABSTRACT We examined the response of pico-phytoplankton communities sampled at the equatorial, tropical and temperate Central Atlantic Ocean to subsurface underwater solar radiation in order to test the generality of the reported cell mortality for these populations when exposed to high ultra violet radiation (UVR) and photosynthetically active radiation. The natural communities of pico-phytoplankton populations tested experienced high cell mortality when exposed to high solar radiation, despite inhabiting tropical waters. Synechococcus and eukaryotes were more resistant to solar radiation than Prochlorococcus. The decay rates of all pico-phytoplankton groups examined tended to be much higher when exposed to total solar radiation than when UVB-R was filtered out. We also show that even short exposures of 30 min to high solar radiation were able to induce cell mortality in Prochlorococcus. The variability in the decay rates of living Prochlorococcus cells were strongly related to the condition of the original population. However, Synechococcus decay rates were higher in populations from the tropical area, with eukaryotes sensitivity increasing with increasing the trophic degree. The data reported in this study and in the literature revealed contrasting capacities of Prochlorococcus, Synechococcus and eukaryotes to survive under high solar radiation. Although the mechanisms involved are as yet unclear, their elucidation may help explain niche partitioning among these organisms in the ocean. [source] Three-year follow-up of the first prospective randomized comparison between paclitaxel and sirolimus stents: The TAXi-LATE trialCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2007Alexandre Berger MD Abstract Goal: Analysis of the 3-year outcome of the original population of the TAXi trial which compared the efficacy of the paclitaxel (PES) and the sirolimus (SES) stents in a randomized "real world" investigation. History: The widespread use of drug-eluting stents strongly modified the world of interventional cardiology. The TAXi trial was a randomized comparison between PES and SES and showed similar efficacy between the two prostheses. Recently, emerging discussions raised questions about potential long-term risk with the use of DES. The present work attempts to describe the long-term outcome of the patients compared during the TAXi trial. Method: During April 2003 and January 2004, 202 patients were prospectively randomly assigned to the PES group (102 patients) and to the SES group (100 patients). The primary aim of the present investigation was the comparison of combined incidence of cardiac death, myocardial infarction, and target lesion revascularization within 36-months. Results: No difference in mortality of all causes was noted in the PES and the SES groups (3% vs. 7%, P = 0.98) or in major adverse cardiac event free survival (89% vs. 83%, P = 0.28). Four stent thromboses were observed, two in the PES group (205 and 788 days) and two in the SES group (210 and 772 days). Conclusion: The long-term outcome analysis of the TAXi trial confirms available published data showing the equivalence of PES and SES on clinical basis. © 2007 Wiley-Liss, Inc. [source] Prevailing triple infection with Wolbachia in Callosobruchus chinensis (Coleoptera: Bruchidae)MOLECULAR ECOLOGY, Issue 2 2002Natsuko Kondo Abstract Prevailing triple infection with three distinct Wolbachia strains was identified in Japanese populations of the adzuki bean beetle, Callosobruchus chinensis. When a polymerase chain reaction (PCR) assay was conducted using universal primers for ftsZ and wsp, Wolbachia was detected in all the individuals examined, 288 males and 334 females from nine Japanese populations. PCR,restriction fragment length polymorphism (RFLP) analysis of cloned wsp gene fragments from single insects revealed that three types of wsp sequences coexist in the insects. Molecular phylogenetic analysis of the wsp sequences unequivocally demonstrated that C. chinensis harbours three phylogenetically distinct Wolbachia, tentatively designated as wBruCon, wBruOri and wBruAus, respectively. Diagnostic PCR analysis using specific primers demonstrated that, of 175 males and 235 females from nine local populations, infection frequencies with wBruCon, wBruOri and wBruAus were 100%, 96.3% and 97.0%, respectively. As for the infection status of individuals, triple infection (93.7%) dominated over double infection (6.1%) and single infection (0.2%). The amounts of wBruCon, wBruOri and wBruAus in field-collected adult insects were analysed by using a quantitative PCR technique in terms of wsp gene copies per individual insect. Irrespective of original populations, wBruCon and wBruOri (107,108wsp copies/insect) were consistently greater in amount than wBruAus (106,107wsp copies/insect), suggesting that the population sizes of the three Wolbachia strains are controlled, although the mechanism is unknown. Mating experiments suggested that the three Wolbachia cause cytoplasmic incompatibility at different levels of intensity. [source] | |||||||||||||