Search results for "Variation"
showing 10 items of 2124 documents
Northern Drosophila montana flies show variation both within and between cline populations in the critical day length evoking reproductive diapause
2013
Reproductive diapause, and its correct timing, plays an important role in the life cycle of many insect species living in a seasonally varying environment at high latitudes. In the present paper we have documented variation in the critical day length (CDL) for adult reproductive diapause and the steepness of photoperiodic response curves (PPRCs) in seven clinal populations of Drosophila montana in Finland between the latitudes 61 and 67°N, paying special attention to variation in these traits within and between cline populations. The isofemale lines representing these populations showed a sharp transition from 0% to 100% in females' diapause incidence in the shortening day lengths, indicate…
Ground-Mounted Photovoltaic and Crop Cultivation: A Comparative Analysis
2022
Human civilization depends on energy sources, mainly fossil fuels. An increase in the prices of fossil fuels and their exhaustibility limit economic growth. Carbon dioxide emission causes global environmental problems. Global crises (including COVID-19) have sharpened food and energy supply problems. The decentralized energy supply systems as well as the expedition of the application of renewable energy may solve these challenges. The economic shift to renewable power generation intensifies the competition between food crop production and green energy for land. This paper applied an open-source spatial-based model to quantify the solar power generation (the ground-mounted photovoltaic panel…
Maternally‐transferred thyroid hormones and life‐history variation in birds
2022
1. In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early-phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in maternal THs within the physiological range can influence offspring phenotype. 2. Given the essential functions of maternal THs in development and metabolism, THs may be a mediator of life-history variation across species. 3. We tested the hypothesis that differences in life histories are associated with differences in maternal TH transfer across species…
Slight variations in components ratio affect odor pleasantness of a blending mixture
2009
International audience; Odors rely mainly on the perception of odorants mixtures but are commonly perceived as single undivided entities; nevertheless, the processes involved remain poorly explored. It has been reported that perceptual blending, based on configural olfactory processing, can lead odorant mixtures to give rise to an emergent odor quality not present in the components. Furthermore, very slight variations (just noticeable differences, jnd) in components concentrations were shown to be sufficient to modify the odor quality of a blending mixture. In the present study, we set out to examine whether jnd in components concentrations could also affect the odor pleasantness of a blend…
On the Porosity of Free Boundaries in Degenerate Variational Inequalities
2000
Abstract In this note we consider a certain degenerate variational problem with constraint identically zero. The exact growth of the solution near the free boundary is established. A consequence of this is that the free boundary is porous and therefore its Hausdorff dimension is less than N and hence it is of Lebesgue measure zero.
Two positive solutions for a nonlinear parameter-depending algebraic system
2021
The existence of two positive solutions for a nonlinear parameter-depending algebraic system is investigated. The main tools are a finite dimensional version of a two critical point theorem and a recent weak-strong discrete maximum principle.
Two positive solutions for a nonlinear parameter-depending algebraic system
2021
The existence of two positive solutions for a nonlinear parameter-depending algebraic system is investigated. The main tools are a finite dimensional version of a two critical point theorem and a recent weak-strong discrete maximum principle.
Taking it a tad further : comparing English and Swedish course materials in terms of presenting prosody and accent variation
2011
Tämän tutkimuksen aiheena on prosodian ja aksenttivariaatioiden esiintyminen lukion englannin ja ruotsin oppikirjamateriaaleissa. Ääntämisen opetusta ja osaamista on koulutuksen piirissä ensisijaisesti tutkittu segmentaalien näkökulmaa painottaen, vaikka nimenomaisesti prosodisten ainesten on todettu vaikuttavan puheen ymmärrettävyyteen segmentaalitarkkuutta enemmän. Aksenttivariaatiot ovat niin ikään vaikuttava tekijä puheen suurien linjojen piirissä, ja niiden eroihin vaikuttaa segmentaalimuutosten lisäksi prosodinen vaihtelu. Prosodian käsite itsessään sisältää yksittäisten äänteiden yliset ilmiöt, jotka voidaan jakaa kolmeen osa-alueeseen: äänteiden kvantiteettiin (paino ja pituus), kva…
Does daily distress make parents prone to using psychologically controlling parenting?
2016
The aim of the present study was to investigate whether parental daily distress in terms of negative emotions is associated with the daily variation in parental use of psychological control with their children. Whether parental positive emotions play a role in the use of psychological control was also investigated. The participants were 149 Finnish families with a child between the ages of 6 and 7 years. Parents’ negative and positive emotions, children’s misconduct, and parental use of psychological control when interacting with their children were measured daily using diary questionnaires filled in by the mothers and fathers over 7 successive days in the fall term of the children’s first…
Determinants of the interannual relationships between remote sensed photosynthetic activity and rainfall in tropical Africa
2007
International audience; The response of photosynthetic activity to interannual rainfall variations in Africa South of the Sahara is examined using 20 years (1981-2000) of Normalised Difference Vegetation Index (NDVI) AVHRR data. Linear correlations and regressions were computed between annual NDVI and annual rainfall at a 0.5° latitude/longitude resolution, based on two gridded precipitation datasets (Climate Prediction Center Merged Analysis of Precipitation [CMAP] and Climatic Research Unit [CRU]). The spatial patterns were then examined to detect how they relate to the mean annual rainfall amounts, land-cover types as from the Global Land Cover 2000 data set, soil properties and soil typ…