Search results for "Population"

Absence of the lactase-persistence-associated allele in early Neolithic Europeans.

2007

Lactase persistence (LP), the dominant Mendelian trait conferring the ability to digest the milk sugar lactose in adults, has risen to high frequency in central and northern Europeans in the last 20,000 years. This trait is likely to have conferred a selective advantage in individuals who consume appreciable amounts of unfermented milk. Some have argued for the “culture-historical hypothesis,” whereby LP alleles were rare until the advent of dairying early in the Neolithic but then rose rapidly in frequency under natural selection. Others favor the “reverse cause hypothesis,” whereby dairying was adopted in populations with preadaptive high LP allele frequencies. Analysis based on the cons…

Reproducibility and validity of a food frequency questionnaire among pregnant women in a Mediterranean area

2013

Background: Studies exploring the role of diet during pregnancy are still scarce, in part due to the complexity of measuring diet and to the lack of valid instruments. The aim of this study was to examine the reproducibility and validity (against biochemical biomarkers) of a semi-quantitative food frequency questionnaire (FFQ) in pregnant women. Methods: Participants were 740 pregnant women from a population-based birth cohort study in Valencia (INMA Study). We compared nutrient and food intakes from FFQs estimated for two periods of pregnancy (reproducibility), and compared energy-adjusted intake of several carotenoids, folate, vitamin B12, vitamin C and a-tocopherol of the FFQ in the firs…

Understanding the relationship between subjective health complaints and satisfaction with life for people in prevocational training in Norway

2021

Background and aim: In Norway, a large part of the population is dependent on disability benefits. The main reasons for this are related to long-term musculoskeletal pain and psychological complaints. Prevocational rehabilitation, aimed at increasing participation in working life, targets people in need of a sheltered vocational environment. This group has been found to report a very high level of health complaints. Therefore, a better understanding of the psychological mechanisms affecting satisfaction with life for people who experience subjective health complaints could be important for tailoring more optimal vocational rehabilitation initiatives for these individuals. This study aimed t…

Sex-specific effects of natural and sexual selection on the evolution of life span and ageing in Drosophila simulans

2014

Summary Variation in the strength of age-dependent natural selection shapes differences in ageing rates across species and populations. Likewise, sexual selection can promote divergent patterns of senescence across the sexes. However, the effects of these processes on the evolution of ageing have largely been considered independently, and interactions between them are poorly understood. We use experimental evolution to investigate how natural and sexual selection affect life span and ageing in Drosophila simulans. Replicate populations were evolved under lifetime monogamy (relaxed sexual selection) or lifetime polyandry (elevated sexual selection) and at one of two temperatures, 25 °C (rela…

Mechanisms of population declines in boreal forest grouse

2007

Gilbert Ludwig tutki väitöskirjassaan, miksi kanalinnut ovat vähentyneet talousmetsissä. Suomen metsäkanalintukannat ovat vähentyneet merkittävästi viimeisen 40 vuoden ajan. Pesiin ja poikasiin kohdistuvaa saalistusta on pidetty tärkeimpänä syynä kanalintukantojen laskuun. Hakkuiden ja nuorten metsien osuuden lisääntymisen on katsottu lisänneen myyräkantoja ja niitä syöviä petoja, kuten kettuja, lisäten näin myös kanalintujen pesiin ja poikasiin kohdistuvaa saalistusta. Vuosikymmenten aikana laskenut poikastuotto on keskeisessä roolissa kanalintukantojen laskussa. - Ainakaan teerellä vuotuinen aikuiskuolleisuus ei ole lainkaan lisääntynyt. Hengissäsäilyminen on päinvastoin jopa parantunut, …

Editorial: Searching for the Boundaries of Microbial Speciation in a Rapidly Evolving World

2021

Editorial on the Research Topic.

Variation in developmental mode and its effects on divergence and maintenance of populations

2012

Tuberculosis among Migrant Populations in Sicily: A Field Report

2021

Background. In the EU, tuberculosis (TB) mainly affects vulnerable people, including migrants. From 2014 to 2017, we have estimated the frequency of both tuberculosis and latent tuberculosis infection (LTBI) among the migrant population hosted in 41 reception centers in western Sicily (ITaCA network). Materials and Methods. All migrants were consecutively recruited for the screening of TB infection with physical examination and TST in 1,020 migrants and with IGRA in the others 2,690. The screening was carried out 4–8 weeks after landing in Sicily. For all migrants with a positive screening test, chest X-ray and smear examination were performed. LTBI was defined by positivity of TST or IGRA …

Fear of COVID-19 as a buffer in the relationship between perceived stress and life satisfaction in the Polish population at the beginning of the glob…

2020

BackgroundCOVID-19 is a significant threat to human life and health. It makes people experience fear, stress, anxiety and mood disor-ders, which have a negative impact on their psychological well-being. The aim of the study was to determine the relation-ship between fear of COVID-19, perceived stress, and life satisfaction during the coronavirus pandemic.Participants and procedure907 Polish people (522 women and 385 men) participated in this study. The Perceived Stress Scale (PSS-10), the Fear of COVID-19 Scale (FOC-6) and the Satisfaction with Life Scale (SWLS) were used in the study.ResultsFear of COVID-19 and perceived stress were positively correlated with each other and both negatively…

Elucidating geological and biological processes underlying the diversification of Sulawesi tarsiers.

2009

Because of their exceptionally long independent evolution, a range diminution of their Eocene relatives, and a remarkable subsequent diversification in Southeast Asia, tarsiers are of particular importance to evolutionary primatologists. Little is known, however, on the processes shaping the radiation of these small enigmatic primates—especially on the Indonesian island of Sulawesi, their center of endemism. Geological reconstructions and progress in applying DNA sequence information to divergence dating now provide us with the tools and background to comprehend tarsier dispersal. Here, we describe effects of plate-tectonic movements, Pleistocene sea level changes, and hybridization on the…