scholarly journals Old and ancient trees are life history lottery winners and act as evolutionary buffers against long-term environmental change

2021 ◽  
Author(s):  
Charles H Cannon ◽  
Gianluca Piovesan ◽  
Sergi Munne-Bosch
Keyword(s):  
Life History ◽  
Environmental History ◽  
Mortality Rates ◽  
Emergent Property ◽  
Age Classes ◽  
Time Variance ◽  
Population Sizes ◽  
Demographic Patterns ◽  
Near Future

Trees can live many centuries with sustained fecundity and death is largely stochastic. We use a neutral stochastic model to examine the demographic patterns that emerge over time, across a range of population sizes and empirically observed mortality rates. A small proportion of trees (~1% at 1.5% mortality) are life-history lottery winners, achieving ages >10-20x median age. Maximum age increases with bigger populations and lower mortality rates. One quarter of trees (~24%) achieve ages that are 3-4 times greater than median age. Three age classes (Mature, Old, and Ancient) contribute unique historical diversity across complex environmental cycles. Ancient trees are an emergent property of forests that requires many centuries to generate. They radically change generation time variance and population fitness, bridging infrequent environmental cycles. These life-history lottery winners are vital to future forest dynamics and invaluable data about environmental history and individual longevity. Old-growth forests contain trees that cannot be replaced through restoration or regeneration in the near future. They simply must be protected to preserve their unique diversity.

Demographic gaps between Syrian and the European populations: What do they suggest?

2017 ◽  
Vol 7 (2) ◽  
pp. 207-230 ◽  
Author(s):  
Mustafa Murat Yucesahin ◽  
Ibrahim Sirkeci
Keyword(s):  
Transition Theory ◽  
World Population ◽  
Demographic Analysis ◽  
Demographic Differences ◽  
Syrian Crisis ◽  
The United Kingdom ◽  
Syrian Population ◽  
Displaced People ◽  
Near Future

Syrian crisis resulted in at least 6.1 million externally displaced people 983,876 of whom are in Europe while the rest are in neighbouring countries in the region. Turkey, due to its geographical proximity and substantial land borders with the country, has been the most popular destination for those fleeing Syria since April 2011. Especially after 2012, a sharp increase in the number of Syrian refugees arriving in Turkey was witnessed. This has triggered an exponential growth in academic and public interest in Syrian population. Numerous reports mostly based on non-representative sample surveys have been disseminated whilst authoritative robust analyses remained absent. This study aims to fill this gap by offering a comprehensive demographic analysis of the Syrian population. We focus on the demographic differences (from 1950s to 2015) and demographic trends (from 2015 to 2100) in medium to long term, based on data from World Population Prospects (WPP). We offer a comparative picture to underline potential changes and convergences between populations in Syria, Turkey, Germany, and the United Kingdom. We frame our discussion here with reference to the demographic transition theory to help understanding the implications for movers and non-movers in receiving countries in the near future.

scholarly journals Contributions to Management Strategies in the NE Atlantic Regarding the Life History and Population Structure of a Key Deep-Sea Fish (Mora moro)

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Régis Santos ◽  
Wendell Medeiros-Leal ◽  
Osman Crespo ◽  
Ana Novoa-Pabon ◽  
Mário Pinho
Keyword(s):  
Population Structure ◽  
Life History ◽  
Deep Sea ◽  
Management Strategies ◽  
Size Composition ◽  
Large Size ◽  
The Common ◽  
Fishing Impacts ◽  
Sea Fish

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

scholarly journals Prediction of Genetic Contributions and Generation Intervals in Populations With Overlapping Generations Under Selection

Genetics ◽  
1999 ◽  
Vol 151 (3) ◽  
pp. 1197-1210 ◽  
Author(s):  
Piter Bijma ◽  
John A Woolliams
Keyword(s):  
Gene Flow ◽  
Overlapping Generations ◽  
Selective Advantage ◽  
Turnover Time ◽  
Breeding Value ◽  
Age Classes ◽  
Generation Interval ◽  
Young Parents ◽  
Genetic Contributions

Abstract A method to predict long-term genetic contributions of ancestors to future generations is studied in detail for a population with overlapping generations under mass or sib index selection. An existing method provides insight into the mechanisms determining the flow of genes through selected populations, and takes account of selection by modeling the long-term genetic contribution as a linear regression on breeding value. Total genetic contributions of age classes are modeled using a modified gene flow approach and long-term predictions are obtained assuming equilibrium genetic parameters. Generation interval was defined as the time in which genetic contributions sum to unity, which is equal to the turnover time of genes. Accurate predictions of long-term genetic contributions of individual animals, as well as total contributions of age classes were obtained. Due to selection, offspring of young parents had an above-average breeding value. Long-term genetic contributions of youngest age classes were therefore higher than expected from the age class distribution of parents, and generation interval was shorter than the average age of parents at birth of their offspring. Due to an increased selective advantage of offspring of young parents, generation interval decreased with increasing heritability and selection intensity. The method was compared to conventional gene flow and showed more accurate predictions of long-term genetic contributions.

scholarly journals Long-Term Monitoring Reveals Differential Responses of Mussel and Host Fish Communities in a Biodiversity Hotspot

Diversity ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 122
Author(s):  
Irene Sanchez Gonzalez ◽  
Garrett W. Hopper ◽  
Jamie Bucholz ◽  
Carla L. Atkinson
Keyword(s):  
Invasive Species ◽  
Life History ◽  
Biodiversity Hotspot ◽  
Biodiversity Hotspots ◽  
Host Fish ◽  
Long Term Monitoring ◽  
Differential Responses ◽  
Taxonomic Groups ◽  
Term Monitoring

Biodiversity hotspots can serve as protected areas that aid in species conservation. Long-term monitoring of multiple taxonomic groups within biodiversity hotspots can offer insight into factors influencing their dynamics. Mussels (Bivalvia: Unionidae) and fish are highly diverse and imperiled groups of organisms with contrasting life histories that should influence their response to ecological factors associated with local and global change. Here we use historical and contemporary fish and mussel survey data to assess fish and mussel community changes over a 33 year period (1986–2019) and relationships between mussel abundance and their host fish abundance in Bogue Chitto Creek, a tributary of the Alabama River and a biodiversity hotspot. Mussel abundance declined by ~80% and community composition shifted, with eight species previously recorded not found in 2019, and a single individual of the endangered Pleurobema decisum. Fish abundances increased and life history strategies in the community appeared stable and there was no apparent relationship between mussel declines and abundance of host fish. Temporal variation in the proportion of life history traits composing mussel assemblages was also indicative of the disturbances specifically affecting the mussel community. However, changes and declines in mussel assemblages in Bogue Chitto Creek cannot be firmly attributed to any specific factor or events because of gaps in historical environmental and biological data. We believe that mobility differences contributed to differential responses of fish and mussel communities to stressors including habitat degradation, recent droughts and invasive species. Overall, our work indicates that monitoring biodiversity hotspots using hydrological measurements, standardized survey methods and monitoring invasive species abundance would better identify the effects of multiple and interactive stressors that impact disparate taxonomic groups in freshwater ecosystems.

scholarly journals Long-Term Exposure to Fine and Coarse Particulate Matter and COVID-19 Incidence and Mortality Rate in Chile during 2020

2021 ◽  
Vol 18 (14) ◽  
pp. 7409
Author(s):  
Macarena Valdés Salgado ◽  
Pamela Smith ◽  
Mariel Opazo ◽  
Nicolás Huneeus
Keyword(s):  
Mortality Rate ◽  
Incidence Rate ◽  
Air Pollutants ◽  
Negative Binomial ◽  
Transport Model ◽  
Surface Concentration ◽  
Mortality Rates ◽  
Incidence And Mortality ◽  
Pm2.5 And Pm10

Background: Several countries have documented the relationship between long-term exposure to air pollutants and epidemiological indicators of the COVID-19 pandemic, such as incidence and mortality. This study aims to explore the association between air pollutants, such as PM2.5 and PM10, and the incidence and mortality rates of COVID-19 during 2020. Methods: The incidence and mortality rates were estimated using the COVID-19 cases and deaths from the Chilean Ministry of Science, and the population size was obtained from the Chilean Institute of Statistics. A chemistry transport model was used to estimate the annual mean surface concentration of PM2.5 and PM10 in a period before the current pandemic. Negative binomial regressions were used to associate the epidemiological information with pollutant concentrations while considering demographic and social confounders. Results: For each microgram per cubic meter, the incidence rate increased by 1.3% regarding PM2.5 and 0.9% regarding PM10. There was no statistically significant relationship between the COVID-19 mortality rate and PM2.5 or PM10. Conclusions: The adjusted regression models showed that the COVID-19 incidence rate was significantly associated with chronic exposure to PM2.5 and PM10, even after adjusting for other variables.

scholarly journals Correctable biliary atresia and cholangiocarcinoma: a case report of a 63-year-old patient

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Masaki Nio ◽  
Motoshi Wada ◽  
Hideyuki Sasaki ◽  
Hiromu Tanaka ◽  
Masatoshi Hashimoto ◽  
...  
Keyword(s):  
Biliary Atresia ◽  
Liver Tumors ◽  
Malignant Tumors ◽  
Porta Hepatis ◽  
Case Presentation ◽  
Cancer Occurrence ◽  
Long Term Survivors ◽  
Near Future

Abstract Background Although cancer occurrence following surgery for biliary atresia has gradually increased, the development of cholangiocarcinoma in a native liver survivor of biliary atresia is extremely rare. Case presentation A 3-month-old female patient with the correctable type of biliary atresia underwent a cystoduodenostomy. At 16 years of age, she underwent multiple surgeries including lysis of intestinal adhesions, ileostomy, and gastrojejunostomy at another hospital. At 54 years of age, she underwent lithotomy at the porta hepatis, resection of the residual cystic bile duct with gallbladder, and hepaticojejunostomy in Roux-en-Y fashion. As she approached the age of 63, her computed tomography scan showed no liver tumors. In the following year, she developed cholangiocarcinoma at the porta hepatis and underwent chemotherapy. However, the cancer progressed, and she died before she reached the age of 64 years. Conclusions Cholangiocarcinoma is extremely rare in patients with biliary atresia. However, physicians should follow up patients with biliary atresia as closely as possible, as malignant tumors secondary to biliary atresia may increase in number in the near future because of the growing number of long-term survivors with biliary atresia.

Management problems in the pregnant diabetic

1993 ◽  
Vol 5 (1) ◽  
pp. 29-38 ◽  
Author(s):  
FA Van Assche
Keyword(s):  
Gestational Diabetes ◽  
Pathological Condition ◽  
Metabolic Adaptation ◽  
Medical Complication ◽  
Mother And Child ◽  
Insulin Dependent ◽  
Underlying Mechanisms ◽  
Near Future ◽  
Pregnant Diabetic

Major progress has been made in the knowledge and management of diabetes and pregnancy. However diabetes in pregnancy remains an important medical complication, with implications for mother and child in both the short and the long term. There are still controversies concerning the diagnostic criteria of gestational diabetes and concerning the best strategry for the treatment of this disorder. There is even less agreement about whether gestational diabetes is a pathological condition. The perinatal mortality in gestational diabetes has recently become as low as that in the general population. This has led to the conclusion that gestational diabetes is no more than a variant of metabolic adaptation during pregnancy. However, fetal hyperinsulinism is present in gestational diabetes, resulting in macrosomia, neonatal complications and most probably long term consequences. Improvements in the care of the preexisting insulin-dependent pregnant diabetic have been achieved but further progress in understanding the underlying mechanisms and in preventing and treating the disease are important goals for the near future.

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