Search results for "hedelmällisyys"
showing 6 items of 6 documents
Prolonged diapause has sex-specific fertility and fitness costs
2019
AbstractDiapause in seasonal environments allows insects to survive adverse seasons. However, individuals can sometimes enter a prolonged diapause for more than a year, and also skip favourable seasons, which can bring additional costs through e.g. loss of metabolic resources. At the same time, prolonged diapause can be beneficial if it allows individuals to have a risk-spreading strategy to skip potentially suboptimal breeding seasons. We studied if prolonged diapause (2-year diapause) negatively affects the fertility and fitness of female and male Colorado potato beetles (Leptinotarsa decemlineata) compared to control (1-year diapause) beetles. We also tested the parental effects on the s…
A multi-criteria evaluation system for arable land resource assessment
2020
This study proposed a multi-criteria evaluation system for arable land resources by combining the soil integrated fertility index (IFI) with a soil cleanliness index (based on heavy metals and metalloid content). A total of 16 typical arable land units in Chongming District, China, were evaluated using the proposed evaluation system based on 104 collected soil samples in 16 towns. The comprehensive soil evaluation scores of arable lands in 16 towns were in the range of 90.7 to 99.2 with a mean of 96.2, indicating that the arable land in all 16 towns was at the level of excellent (≥ 90.0). Lower cleanliness indices had a significant impact on the final evaluation score. In comparison with si…
The effect of job displacement on couples' fertility decisions
2016
This paper analyzes the effects of job displacement on fertility using Finnish longitudinal employer-employee data (FLEED) matched to birth records. We distinguish between male and female job losses. We focus on couples where one spouse has lost his/her job due to a plant closure or mass layoff and follow them for several years both before and following the job loss. As a comparison group we use similar couples that were not affected by job displacement. In order to examine the possible channels through which job loss affects fertility we examine also the effect on earnings, employment and divorce. The results show that a woman?s own job loss decreases fertility mainly for highly educated w…
Do highly ornamented and less parasitized males have high quality sperm? - an experimental test for parasite-induced reproductive trade-offs in Europ…
2014
Parasites take their resources from hosts and thus directly reduce available resources for hosts’ own body functions, such as growth and reproduction. Furthermore, parasite infections cause significant indirect costs to their hosts in terms of increased investments on immune defense. In this study, we investigated the impact of parasite infection on the sperm quality and expression of secondary sexual ornamentation (saturation of the red abdominal colouration and number of breeding tubercles) in the Eurasian minnow (Phoxinus phoxinus). We exposed minnows to a high and low dose of common nonspecific fish ectoparasite, the glochidia larvae of duck mussel (Anodonta anatina) and tested whether …
Lapsettomuustutkimuksiin hakeutuvien naisten näkemyksiä painonhallinnan, ravitsemuksen ja liikunnan vaikutuksesta hedelmällisyyteen
2016
Terhi Kemilä (2016). Lapsettomuustutkimuksiin hakeutuvien naisten näkemyksiä painonhallinnan, ravitsemuksen ja liikunnan vaikutuksesta hedelmällisyyteen. Terveystieteiden laitos, Jyväskylän yliopisto, Terveyskasvatuksen pro gradu -tutkielma, 40 s., 3 liitettä. Lapsettomuuden on arvioitu yleistyneen viime vuosikymmeninä, Suomessa lapsettomuushoitoihin hakeutuvien määrä on ollut hienoisessa nousussa. Elintapojen vaikutusta hedelmällisyyteen on tutkittu laajasti ja tiedetään, että yli- ja alipaino, ravitsemus sekä liikunta vaikuttavat naisten hedelmällisyyteen. Tämän tutkimuksen tarkoituksena oli selvittää lapsettomuustutkimuksiin hakeutuvien naisten näkemyksiä elintapojen vaikutuksesta hedelm…