The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
John M. Maniscalco - One of the best experts on this subject based on the ideXlab platform.
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methyl mercury mehg in vitro exposure alters mitogen induced lymphocyte proliferation and cytokine expression in steller sea lion eumetopias jubatus pups
Science of The Total Environment, 2020Co-Authors: Milton Levin, John M. Maniscalco, Lindsay Jasperse, Jeanpierre Desforges, Todd M Ohara, Lorrie D Rea, Margaret J Castellini, Brian S Fadely, Mandy KeoghAbstract:Abstract Steller sea lions (Eumetopias jubatus, SSLs) are managed as two distinct Population Segments within U.S. waters: the endangered western distinct Population Segment and the recently delisted eastern distinct Population Segment. Recent studies reported concentrations of mercury in several tissues collected from young SSLs in the Aleutian Islands that were at or above concentrations found to negatively impact health in other fish-eating mammals. However, there are limited studies which have investigated the range of mercury concentrations that may negatively influence the SSL immune system. This study assessed relationships between methyl mercury (MeHg+) concentrations and two immune functions, lymphocyte proliferation and cytokine expression. Peripheral blood mononuclear cells (PBMCs) were isolated and cryopreserved from pups on three rookeries within the western distinct Population Segment: Chiswell Island, Ulak, and Agattu Islands. Lymphocyte proliferation and cytokine expression were assessed in vitro using thawed PBMCs with exposure to MeHg+ (unexposed control, 0.001, 0.01, and 0.1 μg/ml). Lymphocyte proliferation was measured without and with stimulation with a T cell mitogen (ConA) and B cell mitogen (LPS) and the concentration of cytokines was measured in the cell culture supernatant (with and without ConA or LPS). Spontaneous lymphocyte proliferation was significantly increased at 0.01 and 0.1 μg/ml. T lymphocyte proliferation was significantly increased at 0.001 μg/ml and 0.1 μg/ml, while B lymphocyte proliferation was decreased at 0.1 μg/ml. Cytokine concentrations for INFγ, IL-10, IL-6, and TNFα were reduced at 0.1 μg/ml upon either T or B cell mitogen stimulation, with the exception for IL-10, where 0.1 μg/ml reduced IL-10 concentration compared to unstimulated cells. These data suggest immune functions were affected by MeHg+ exposure requiring in vivo follow up investigations. The observed modulation of immune functions is of concern as any toxicant-induced modulation may adversely affect the health of individuals, particularly younger animals undergoing periods of critical development.
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RESEARCH ARTICLE Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska: A New Life-History Table Analysis
2016Co-Authors: John M. Maniscalco, Alan M. Springer, Milo D. Adkison, Pamela ParkerAbstract:Steller sea lion (Eumetopias jubatus) numbers are beginning to recover across most of the western distinct Population Segment following catastrophic declines that began in the 1970s and ended around the turn of the century. This study makes use of contemporary vital rate estimates from a trend-site rookery in the eastern Gulf of Alaska (a sub-region of the west-ern Population) in a matrix Population model to estimate the trend and strength of the recov-ery across this region between 2003 and 2013. The modeled Population trend was projected into the future based on observed variation in vital rates and a prospective elastic-ity analysis was conducted to determine future trends and which vital rates pose the great-est threats to recovery. The modeled Population grew at a mean rate of 3.5 % per yr between 2003 and 2013 and was correlated with census count data from the local rookery and throughout the eastern Gulf of Alaska. If recent vital rate estimates continue with little change, the eastern Gulf of Alaska Population could be fully recovered to pre-decline levels within 23 years. With density dependent growth, the Population would need another 45 years to fully recover. Elasticity analysis showed that, as expected, Population growth rate (λ) was most sensitive to changes in adult survival, less sensitive to changes in juvenile sur-vival, and least sensitive to changes in fecundity. A Population decline could be expected with only a 6 % decrease in adult survival, whereas a 32 % decrease in fecundity would be necessary to bring about a Population decline. These results have important implications for Population management and suggest current research priorities should be shifted to a greater emphasis on survival rates and causes of mortality
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Inter-Population Movements of Steller Sea Lions in Alaska with Implications for Population Separation
2015Co-Authors: Lauri A. Jemison, John M. Maniscalco, Grey W. Pendleton, Lowell W. Fritz, Kelly K. Hastings, Andrew W. Trites, Tom S. GelattAbstract:Genetic studies and differing Population trends support the separation of Steller sea lions (Eumetopias jubatus) into a western distinct Population Segment (WDPS) and an eastern DPS (EDPS) with the dividing line between Populations at 144u W. Despite little exchange for thousands of years, the gap between the breeding ranges narrowed during the past 15–30 years with the formation of new rookeries near the DPS boundary. We analyzed.22,000 sightings of 4,172 sea lions branded as pups in each DPS from 2000–2010 to estimate probabilities of a sea lion born in one DPS being seen within the range of the other DPS (either ‘West ’ or ‘East’). Males from both Populations regularly traveled across the DPS boundary; probabilities were highest at ages 2–5 and for males born in Prince William Sound and southern Southeast Alaska. The probability of WDPS females being in the East at age 5 was 0.067 but 0 for EDPS females which rarely traveled to the West. Prince William Sound-born females had high probabilities of being in the East during breeding and non-breeding seasons. We present strong evidence that WDPS females have permanently emigrated to the East, reproducing at two ‘mixing zone’ rookeries. We documented breeding bulls that traveled.6,500 km round trip from their natal rookery in southern Alaska to the northern Bering Sea and central Aleutian Islands and back within one year. WDPS animals began moving East in the 1990s, following steep Population declines in the central Gulf of Alaska. Results of our study, and others documenting high survival and rapid Population growth in northern Southeast Alaska suggest that conditions in this mixing zone region hav
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Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska: A New Life-History Table Analysis
PloS one, 2015Co-Authors: John M. Maniscalco, Alan M. Springer, Milo D. Adkison, Pamela ParkerAbstract:Steller sea lion (Eumetopias jubatus) numbers are beginning to recover across most of the western distinct Population Segment following catastrophic declines that began in the 1970s and ended around the turn of the century. This study makes use of contemporary vital rate estimates from a trend-site rookery in the eastern Gulf of Alaska (a sub-region of the western Population) in a matrix Population model to estimate the trend and strength of the recovery across this region between 2003 and 2013. The modeled Population trend was projected into the future based on observed variation in vital rates and a prospective elasticity analysis was conducted to determine future trends and which vital rates pose the greatest threats to recovery. The modeled Population grew at a mean rate of 3.5% per yr between 2003 and 2013 and was correlated with census count data from the local rookery and throughout the eastern Gulf of Alaska. If recent vital rate estimates continue with little change, the eastern Gulf of Alaska Population could be fully recovered to pre-decline levels within 23 years. With density dependent growth, the Population would need another 45 years to fully recover. Elasticity analysis showed that, as expected, Population growth rate (λ) was most sensitive to changes in adult survival, less sensitive to changes in juvenile survival, and least sensitive to changes in fecundity. A Population decline could be expected with only a 6% decrease in adult survival, whereas a 32% decrease in fecundity would be necessary to bring about a Population decline. These results have important implications for Population management and suggest current research priorities should be shifted to a greater emphasis on survival rates and causes of mortality.
Per Hildebrandt - One of the best experts on this subject based on the ideXlab platform.
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the prognosis of impaired left ventricular systolic function and heart failure in a middle aged and elderly Population in an urban Population Segment of copenhagen
European Journal of Heart Failure, 2004Co-Authors: Ilan Raymond, Frants Pedersen, J Jacobsen, Jesper Mehlsen, Jeannett Dimsits, Per HildebrandtAbstract:Aims: To determine the prognosis, total mortality and cardiac morbidity, of patients with left ventricular systolic dysfunction and heart failure (HF) in a general Population sample. Methods and results: A total of 764 subjects, 432 females and 332 males, median age (range) 66 years (50–89), participated in this cross sectional survey. The study Population was recruited from randomly selected general practitioners and stratified to include a minimum of 150 persons in each age decade stratum. Each participant filled in a heart failure questionnaire and ECG, blood tests and echocardiography were performed. Median (range) follow-up was 1145 (51–1197) days. Subjects with LVEF≤0.40 had a significantly higher all-cause mortality (27.8% vs. 5.6%, P 0.40. The age and gender adjusted 2-year relative risk of death was 4.6 (95% C.I.=1.6–13.2). No significant difference in mortality was found between subjects with or without heart failure symptoms. Conclusion: Significantly higher mortality as well as cardiac morbidity was found in subjects with symptomatic and asymptomatic LV systolic dysfunction compared to those with normal systolic function. These conditions were among the strongest predictors of all-cause mortality and cardiac morbidity.
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prevalence of impaired left ventricular systolic function and heart failure in a middle aged and elderly urban Population Segment of copenhagen
Heart, 2003Co-Authors: Ilan Raymond, Frants Pedersen, F Steensgaardhansen, A Green, M Buschsorensen, Christian Tuxen, J Appel, J Jacobsen, Dan Atar, Per HildebrandtAbstract:Objective: To assess the prevalence of impaired left ventricular systolic function and manifest heart failure in a general Population aged 50–89 years. Design: In this cross sectional survey, participants filled in a heart failure questionnaire. ECG, blood tests, and echocardiography were performed. Setting: The study Population was recruited from general practitioners situated in the same urban area and examined in a university hospital in Copenhagen, Denmark. Participants: 764 participants (432 women and 332 men, median (SD) age 66 (11) years) participated. The study Population was stratified to include a minimum of 150 persons in each age decade. Main outcome measures: Prevalence of impaired systolic function and manifest heart failure. Results: The prevalence of systolic dysfunction (left ventricular ejection fraction ⩽ 40%) was more than twice as high among men (7.6%) as among women (2.6%). In the male Population systolic heart failure (left ventricular ejection fraction ⩽ 40% and symptoms) was found in 1.8% of the 50–59 years age group and approximately doubled for each age decade to reach 13.9% in octogenarians. Among women systolic dysfunction increased from 0.8% to 4.3% in the same age groups. Asymptomatic cases accounted for 44.0% of all cases of systolic dysfunction in the male Population and only 9.1% in the female Population. Conclusions: In this age controlled Population study impaired left ventricular systolic function and heart failure increased substantially with age and was more than twice as frequent among men as among women. Asymptomatic left ventricular dysfunction occurred more frequently in men than in women and was less prevalent with increasing age.
Pamela Parker - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska: A New Life-History Table Analysis
2016Co-Authors: John M. Maniscalco, Alan M. Springer, Milo D. Adkison, Pamela ParkerAbstract:Steller sea lion (Eumetopias jubatus) numbers are beginning to recover across most of the western distinct Population Segment following catastrophic declines that began in the 1970s and ended around the turn of the century. This study makes use of contemporary vital rate estimates from a trend-site rookery in the eastern Gulf of Alaska (a sub-region of the west-ern Population) in a matrix Population model to estimate the trend and strength of the recov-ery across this region between 2003 and 2013. The modeled Population trend was projected into the future based on observed variation in vital rates and a prospective elastic-ity analysis was conducted to determine future trends and which vital rates pose the great-est threats to recovery. The modeled Population grew at a mean rate of 3.5 % per yr between 2003 and 2013 and was correlated with census count data from the local rookery and throughout the eastern Gulf of Alaska. If recent vital rate estimates continue with little change, the eastern Gulf of Alaska Population could be fully recovered to pre-decline levels within 23 years. With density dependent growth, the Population would need another 45 years to fully recover. Elasticity analysis showed that, as expected, Population growth rate (λ) was most sensitive to changes in adult survival, less sensitive to changes in juvenile sur-vival, and least sensitive to changes in fecundity. A Population decline could be expected with only a 6 % decrease in adult survival, whereas a 32 % decrease in fecundity would be necessary to bring about a Population decline. These results have important implications for Population management and suggest current research priorities should be shifted to a greater emphasis on survival rates and causes of mortality
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Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska: A New Life-History Table Analysis
PloS one, 2015Co-Authors: John M. Maniscalco, Alan M. Springer, Milo D. Adkison, Pamela ParkerAbstract:Steller sea lion (Eumetopias jubatus) numbers are beginning to recover across most of the western distinct Population Segment following catastrophic declines that began in the 1970s and ended around the turn of the century. This study makes use of contemporary vital rate estimates from a trend-site rookery in the eastern Gulf of Alaska (a sub-region of the western Population) in a matrix Population model to estimate the trend and strength of the recovery across this region between 2003 and 2013. The modeled Population trend was projected into the future based on observed variation in vital rates and a prospective elasticity analysis was conducted to determine future trends and which vital rates pose the greatest threats to recovery. The modeled Population grew at a mean rate of 3.5% per yr between 2003 and 2013 and was correlated with census count data from the local rookery and throughout the eastern Gulf of Alaska. If recent vital rate estimates continue with little change, the eastern Gulf of Alaska Population could be fully recovered to pre-decline levels within 23 years. With density dependent growth, the Population would need another 45 years to fully recover. Elasticity analysis showed that, as expected, Population growth rate (λ) was most sensitive to changes in adult survival, less sensitive to changes in juvenile survival, and least sensitive to changes in fecundity. A Population decline could be expected with only a 6% decrease in adult survival, whereas a 32% decrease in fecundity would be necessary to bring about a Population decline. These results have important implications for Population management and suggest current research priorities should be shifted to a greater emphasis on survival rates and causes of mortality.
Ilan Raymond - One of the best experts on this subject based on the ideXlab platform.
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the prognosis of impaired left ventricular systolic function and heart failure in a middle aged and elderly Population in an urban Population Segment of copenhagen
European Journal of Heart Failure, 2004Co-Authors: Ilan Raymond, Frants Pedersen, J Jacobsen, Jesper Mehlsen, Jeannett Dimsits, Per HildebrandtAbstract:Aims: To determine the prognosis, total mortality and cardiac morbidity, of patients with left ventricular systolic dysfunction and heart failure (HF) in a general Population sample. Methods and results: A total of 764 subjects, 432 females and 332 males, median age (range) 66 years (50–89), participated in this cross sectional survey. The study Population was recruited from randomly selected general practitioners and stratified to include a minimum of 150 persons in each age decade stratum. Each participant filled in a heart failure questionnaire and ECG, blood tests and echocardiography were performed. Median (range) follow-up was 1145 (51–1197) days. Subjects with LVEF≤0.40 had a significantly higher all-cause mortality (27.8% vs. 5.6%, P 0.40. The age and gender adjusted 2-year relative risk of death was 4.6 (95% C.I.=1.6–13.2). No significant difference in mortality was found between subjects with or without heart failure symptoms. Conclusion: Significantly higher mortality as well as cardiac morbidity was found in subjects with symptomatic and asymptomatic LV systolic dysfunction compared to those with normal systolic function. These conditions were among the strongest predictors of all-cause mortality and cardiac morbidity.
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prevalence of impaired left ventricular systolic function and heart failure in a middle aged and elderly urban Population Segment of copenhagen
Heart, 2003Co-Authors: Ilan Raymond, Frants Pedersen, F Steensgaardhansen, A Green, M Buschsorensen, Christian Tuxen, J Appel, J Jacobsen, Dan Atar, Per HildebrandtAbstract:Objective: To assess the prevalence of impaired left ventricular systolic function and manifest heart failure in a general Population aged 50–89 years. Design: In this cross sectional survey, participants filled in a heart failure questionnaire. ECG, blood tests, and echocardiography were performed. Setting: The study Population was recruited from general practitioners situated in the same urban area and examined in a university hospital in Copenhagen, Denmark. Participants: 764 participants (432 women and 332 men, median (SD) age 66 (11) years) participated. The study Population was stratified to include a minimum of 150 persons in each age decade. Main outcome measures: Prevalence of impaired systolic function and manifest heart failure. Results: The prevalence of systolic dysfunction (left ventricular ejection fraction ⩽ 40%) was more than twice as high among men (7.6%) as among women (2.6%). In the male Population systolic heart failure (left ventricular ejection fraction ⩽ 40% and symptoms) was found in 1.8% of the 50–59 years age group and approximately doubled for each age decade to reach 13.9% in octogenarians. Among women systolic dysfunction increased from 0.8% to 4.3% in the same age groups. Asymptomatic cases accounted for 44.0% of all cases of systolic dysfunction in the male Population and only 9.1% in the female Population. Conclusions: In this age controlled Population study impaired left ventricular systolic function and heart failure increased substantially with age and was more than twice as frequent among men as among women. Asymptomatic left ventricular dysfunction occurred more frequently in men than in women and was less prevalent with increasing age.
Peter S. Coates - One of the best experts on this subject based on the ideXlab platform.
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pinyon and juniper encroachment into sagebrush ecosystems impacts distribution and survival of greater sage grouse
Rangeland Ecology & Management, 2017Co-Authors: Peter S. Coates, Brian G Prochazka, Mark A Ricca, Ben K Gustafson, Pilar T Ziegler, Michael L CasazzaAbstract:ABSTRACT In sagebrush (Artemisia spp.) ecosystems, encroachment of pinyon (Pinus spp.) and juniper (Juniperus spp.; hereafter, “pinyon-junipeRR) trees has increased dramatically since European settlement. Understanding the impacts of this encroachment on behavioral decisions, distributions, and Population dynamics of greater sage-grouse (Centrocercus urophasianus) and other sagebrush obligate species could help benefit sagebrush ecosystem management actions. We employed a novel two-stage Bayesian model that linked avoidance across different levels of pinyon-juniper cover to sage-grouse survival. Our analysis relied on extensive telemetry data collected across 6 yr and seven subPopulations within the Bi-State Distinct Population Segment (DPS), on the border of Nevada and California. The first model stage indicated avoidance behavior for all canopy cover classes on average, but individual grouse exhibited a high degree of heterogeneity in avoidance behavior of the lowest cover class (e.g., scattered i...
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Hierarchical spatial genetic structure in a distinct Population Segment of greater sage-grouse
Conservation Genetics, 2014Co-Authors: Sara J. Oyler-mccance, Michael L Casazza, Jennifer A. Fike, Peter S. CoatesAbstract:Greater sage-grouse ( Centrocercus urophasianus ) within the Bi-State Management Zone (area along the border between Nevada and California) are geographically isolated on the southwestern edge of the species’ range. Previous research demonstrated that this Population is genetically unique, with a high proportion of unique mitochondrial DNA (mtDNA) haplotypes and with significant differences in microsatellite allele frequencies compared to Populations across the species’ range. As a result, this Population was considered a distinct Population Segment (DPS) and was recently proposed for listing as threatened under the U.S. Endangered Species Act. A more comprehensive understanding of the boundaries of this genetically unique Population (where the Bi-State Population begins) and an examination of genetic structure within the Bi-State is needed to help guide effective management decisions. We collected DNA from eight sampling locales within the Bi-State ( N = 181) and compared those samples to previously collected DNA from the two most proximal Populations outside of the Bi-State DPS, generating mtDNA sequence data and amplifying 15 nuclear microsatellites. Both mtDNA and microsatellite analyses support the idea that the Bi-State DPS represents a genetically unique Population, which has likely been separated for thousands of years. Seven mtDNA haplotypes were found exclusively in the Bi-State Population and represented 73 % of individuals, while three haplotypes were shared with neighboring Populations. In the microsatellite analyses both STRUCTURE and FCA separate the Bi-State from the neighboring Populations. We also found genetic structure within the Bi-State as both types of data revealed differences between the northern and southern part of the Bi-State and there was evidence of isolation-by-distance. STRUCTURE revealed three subPopulations within the Bi-State consisting of the northern Pine Nut Mountains (PNa), mid Bi-State, and White Mountains (WM) following a north–south gradient. This genetic subdivision within the Bi-State is likely the result of habitat loss and fragmentation that has been exacerbated by recent human activities and the encroachment of singleleaf pinyon ( Pinus monophylla ) and juniper ( Juniperus spp.) trees. While genetic concerns may be only one of many priorities for the conservation and management of the Bi-State greater sage-grouse, we believe that they warrant attention along with other issues (e.g., quality of sagebrush habitat, preventing future loss of habitat). Management actions that promote genetic connectivity, especially with respect to WM and PNa, may be critical to the long-term viability of the Bi-State DPS.