Search results for "EGG"
showing 10 items of 881 documents
Prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks
2005
Avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. As androgens may suppress immune functions, they may also entail costs for the chick. This is particularly relevant for colonial species, such as the black-headed gull (Larus ridibundus), in which the aggregation of large numbers of birds during the breeding season enhances the risk of infectious diseases for the hatching chick.To test the effect of maternal yolk androgens on the chick's immune function, we experimentally manipulated, in a field study, yolk androgen levels within the physiological range by in ovo injection of either a…
Increase of trans-resveratrol in typical Sicilian wine using β-Glucosidase from various sources
2008
β-Glucosidase (EC 3.2.1.21) (β-G) from different sources were tested to increase the trans-resveratrol in some Sicilian wines by hydrolysing resveratrol glucoside. β-G from Aspergillus niger mould was tested as a crude and purified enzyme, and compared with the same enzyme from Saccharomyces cerevisiae yeast. Specific purification served to eliminate collateral enzyme activities so that β-G could be used simply and economically. Aspergillus niger β-G produced trans-resveratrol increases of up to 75%, with no change in physico-chemical properties and bouquet, and an increase in health and nutritional properties. S. cerevisiae β-G raised free-terpenol levels, but impaired wine colour due to a…
Intersezioni ai bordi del linguaggio. Note su Wittgenstein e Heidegger
2008
Prosjektarbeid i barnehagen – mellom bekvemmelighet og medvirkning
2021
I denne artikkelen analyseres samtaler fra personalmøter i to barnehager som arbeider prosjektbasert inspirert av Reggio Emilia-pedagogikk. Observasjoner av møter er supplert med intervju med de pedagogiske lederne. Målet med undersøkelsen har vært å studere hvordan personalet snakker sammen om arbeid med prosjekt i møtene og hvordan dette kan ha betydning for barns mulighet for medvirkning. Vi viser hvordan samtalene arter seg gjennom et prosjektforløp. Underveis i denne prosessen identifiserte vi fire ulike diskurser som på ulike måter legger føringer for barnas medvirkning i arbeidet med prosjektene. Vi har kalt disse for henholdsvis en medvirkningsdiskurs, en undringsdiskurs, en bekvemm…
Local Structure of Supported Keggin and Wells-Dawson Heteropolyacids and Its Influence on the Catalytic Activity
2019
[EN] Keggin [PW12O40]3– and Wells–Dawson [P2W18O62]6– heteropolyanions are nanosized transition-metal-oxygen clusters belonging to the heteropolyacids (HPAs) family. They are widely used as catalysts due to their high Brønsted acidity, and their dispersion on solid supports favors the accessibility to their acid sites generally increasing the catalytic activity. A series of binary materials composed of Keggin or Wells–Dawson HPAs and SiO2, TiO2, and ZrO2 have been prepared by impregnation or solvothermal methods. Remarkable differences have been found in the catalytic activities among the unsupported and supported HPAs. These differences have been correlated in the past to the structural ch…
Food supplementation reveals constraints and adaptability of egg quality in the magpie Pica pica
2015
Differences in the deposition of limited maternal resources to eggs can reflect the optimal allocation to manipulate offspring phenotype, or constraints caused by maternal condition. We examined multiple maternal substances transferred to eggs in the magpie Pica pica to test the hypothesis that certain substances represent constraint and some optimal allocation. We did this by supplementary feeding magpies prior to egg-laying and then comparing the effect of food on maternal substances in conjunction with laying order relative to a control group. Certain substances such as carotenoids, immunoglobulins and avidin responded positively to food supplementation, whereas others, such as testoste…
Adolescenti e stile “Young Adult”
2021
Molto spesso dimentichiamo quello che significa essere adolescenti. Molto spesso dimentichiamo quello che è uno degli aspetti più importanti della letteratura: arrivare a toccare le corde dell’animo e del cuore dei lettori, in un modo che allo stesso tempo intrattiene e gli permette di sentirsi compresi e meno soli, di sentirsi umani. L'adolescenza è la terra dei contrasti, delle grandi emozioni vissute e la letteratura può svolgere una funzione utile aiutando gli adolescenti a sentirsi meno soli. Leggere richiede coraggio, perché accogliere qualcosa, riconoscerla, significa mettersi in gioco personalmente. Il libro offre all’adolescente una visione di sé, non solo “qui ed ora”, ma dona una…
Quantitative aspects of egg-laying behaviour contribute to the eruptive success of Cameraria ohridella parasiting horse-chestnuts.
2015
5 pages; International audience; The invasive leaf-mining moth, Cameraria ohridella, revealed to be a consistent eruptive species throughout Europe, at the expense of its host, the common horse chest-nut tree Aesculus hippocastanum. Its repeated outbreaks, year after year, are admittedly caused, in part, by the inadequacy of the ambient cortege of natural enemies as an effective mean of control of the dynamics of populations of this pest.Less attention has been given to other parameters also contributing to the moth’s impact in term of mines density, such as (i) the degree of selectivity of C. ohridella mothers among host-leaves prior to oviposition and (ii) the average clutch-size.Although…
Modification of hosts' behavior by a parasite: field evidence for adaptive manipulation.
2007
9 pages; International audience; Parasites relying on trophic transmission to complete their life cycles often induce modifications of their host's behavior in ways that may increase their susceptibility to predation by final hosts. These modifications have often been interpreted as parasite adaptations, but very few studies have demonstrated that host manipulation has fitness benefits for the parasite. The aim of the present study was to address the adaptive significance of parasite manipulation by coupling observations of behavioral manipulation to estimates of trophic transmission to the definitive host in the natural environment. We show that the acanthocephalan parasite Pomphorhynchus …
Host plant cultivar of the grapevine moth Lobesia botrana affects the life history traits of an egg parasitoid.
2009
6 pages; International audience; The quality and susceptibility of insect eggs for egg parasitoids may be affected by the diet experienced by the females that produce the host eggs. We tested the hypothesis that the host plant fed upon by an herbivore during the larval stages will determine the quality of the eggs laid by the adult for an egg parasitoid. We used the tritrophic system comprising five grape cultivars, the European grapevine moth, Lobesia botrana and the parasitoid Trichogramma evanescens. Parasitoid performance in host eggs of different sizes and originating from five grape cultivars was determined. Overall, egg parasitism was higher on cultivars on which L. botrana laid larg…