324,385 research outputs found
A fixed energetic ceiling to parental effort in the great tit?
Get PDF1. To elucidate the links between avian brood size, parental effort and parental investment, we measured daily energy expenditure (DEEfem), condition (residuals of mass on tarsus) and feeding rate in female great tits Parus major L. rearing broods in which the number of young was either reduced, unmanipulated or enlarged. 2. Female condition was negatively correlated with manipulation when measured at the nestling age of 8 days (measured during the day), which suggests a shift in allocation from self-feeding to chick-feeding. However, there was no detectable manipulation effect on condition measured at the nestling age of 12 days (measured during the night). Either female condition was only affected by manipulation in the early nestling phase or the females adjusted their diurnal mass trajectory in response to brood size manipulation. More detailed data are required to verify this point. There were no indications of a fitness cost associated with the condition during the day, but condition at night was positively related to winter survival. Since manipulation only affected condition during the day, there was no link between manipulation and winter survival. 3. The duration of the working day was not affected by manipulation and female feeding rate tended to flatten off with manipulated brood size. Similarly, brood reduction resulted in a lower DEEfem, whilst brood enlargement had no effect. This suggests that females worked at an energetic ceiling when rearing an unmanipulated brood. However, the level of this 'ceiling' in DEEfem was not fixed: it differed between years. This leads us to conclude that the observed ceiling was imposed by extrinsic factors (e.g. available foraging time) and not by an intrinsic factor such as maximum energy assimilation rate. We hypothesize that time limitation was the cause for the observed ceiling in energy expenditure and that the annual variation in the level of this ceiling was due to annual variation in ambient temperature. 4. A cost of reproduction was previously demonstrated in this population: brood enlargement caused a reduction in the incidence of second clutches. However, since DEEfem did not differ between control and enlarged broods, we judge it unlikely that daily energy expenditure is a general predictor for parental investment. [KEYWORDS: clutch size; condition; energy expenditure; cost of reproduction; parental effort; Parus major L. Starlings sturnus-vulgaris; kestrel falco-tinnunculus; parus-major; brood size; clutch size; blue tits; food availability; feeding frequency; field metabolism; trade-offs]
Henderson (John S.) - Production and Consumption.
No full textVerhulst Michel. Henderson (John S.) - Production and Consumption.. In: Revue économique, volume 6, n°4, 1955. p. 670
Beresîord (M. W.) & St Joseph (J. K. S.). Medieval England. An aerial Survey
No full textVerhulst Adriaan. Beresîord (M. W.) & St Joseph (J. K. S.). Medieval England. An aerial Survey. In: Revue belge de philologie et d'histoire, tome 39, fasc. 3, 1961. Langues et litteratures modernes - Moderne taal- en letterkunde. pp. 876-879
André Chédeville. — Chartres et ses campagnes (XIe-XIIIe s.). Paris, 1973
No full textVerhulst Adriaan-Eduard. André Chédeville. — Chartres et ses campagnes (XIe-XIIIe s.). Paris, 1973. In: Cahiers de civilisation médiévale, 21e année (n°82), Avril-juin 1978. pp. 165-168
Deformation Prediction of Dam Based on Optimized Grey Verhulst Model
No full textDam deformation monitoring data are generally characterized by non-smooth and no-saturated S-type fluctuation. The grey Verhulst model can get better results only when the data series is non-monotonic swing development and the saturated S-shaped sequence. Due to the limitations of the grey Verhulst model, the prediction accuracy will be limited to a certain extent. Aiming at the shortages in the prediction based on the traditional Verhulst model, the optimized grey Verhulst model is proposed to improve the prediction accuracy of the dam deformation monitoring. Compared with those of the traditional GM (1,1) model, the DGM (2,1) model, and the traditional Verhulst (1,1) model, the experimental results show that the new proposed optimized Verhulst model has higher prediction accuracy than the traditional gray model. This study offers an effective model for dealing with the non-saturated fluctuation sequence to predict dam deformation under uncertain conditions
Darby (H. C.) en Campbell (E. M. J.). The Domesday Geography of South-East England Darby (H. C.) en Maxwell (I. S.). The Domesday Geography of Northern England
No full textVerhulst Adriaan. Darby (H. C.) en Campbell (E. M. J.). The Domesday Geography of South-East England Darby (H. C.) en Maxwell (I. S.). The Domesday Geography of Northern England. In: Revue belge de philologie et d'histoire, tome 44, fasc. 2, 1966. Histoire (depuis la fin de l'Antiquité) - Geschiedenis (sedert de Oudheid) pp. 616-618
Léopold Genicot. - L'économie rurale namuroise au bas moyen âge. III : Les hommes - le commun, 1982 (" Rec. trav. d'hist. et philol. ", 6e s., 25)
No full textVerhulst A. E. Léopold Genicot. - L'économie rurale namuroise au bas moyen âge. III : Les hommes - le commun, 1982 (" Rec. trav. d'hist. et philol. ", 6e s., 25). In: Cahiers de civilisation médiévale, 28e année (n°110-111), Avril-septembre 1985. pp. 261-262
SPT 2004 - Symmetry and Perturbation Theory
No full textSPT 2004
Symmetry and Perturbation Theory
30 May - 6 June 2004, Cala Gonone (Sardinia, Italy)
Scientific Committee:
S. Abenda (Bologna, I), D. Bambusi (Milano, I), G. Cicogna (Pisa, I),
A. Degasperis (Roma, I), G. Gaeta (Milano, I), V. Kuznetsov (Leeds, UK),
G. Marmo (Napoli, I), P. Olver (Minneapolis, USA), J.P. Ortega (Besançon, F),
S. Rauch (Linkoping, S), E. Sousa Dias (Lisboa, P), S. Terracini (Milano, I),
F. Verhulst (Utrecht, NL), S. Walcher (Aachen, D), B. Zhilinskii (Dunquerque, F)
Organizing Commitee:
A. Degasperis (Roma), G. Gaeta (Milano), B. Prinari (Lecce), S. Terracini (Milano)
The conference is the fifth of a series begun in 1996. The principal aim of the series of conference is to join together researchers from areas of pure and applied mathematics, physics and chemistry to present their most recent and innovative achievements in the field of symmetries, perturbation and integrable systems.
Conference proceedings are published by World Scientific
Post-natal exposure to corticosterone affects standard metabolic rate in the zebra finch (Taeniopygia guttata)
Get PDFPost-natal stress has been shown to have important short and long term effects on many adult traits in birds. During stress, metabolic alterations often result in the mobilization of energy away from energy-sensitive functions such as growth, which could have significant implications for developing animals. However, little is known about the implications of stress hormones for energy consumption in growing individuals. We experimentally increased corticosterone (CORT) levels in nestling zebra finches via oral administration, between the ages of 7 and 18 days. The standard metabolic rate (SMR) of birds was measured twice overnight when birds were between 11-13 and 55-65 days of age. Developmental CORT administration significantly elevated overnight variability in SMR (sd) in nestling birds (during the treatment period), but not at 55-65 days (5-6 weeks after the treatment period). The effect on variability was seen more prominently in birds from larger brood sizes and in females. We found no effects of our treatments on mean SMR overnight. However, brood size and sex had interactive effects, with males from larger brood sizes having higher SIVIR at 55-65 days of age. These results suggest that stress hormones can have significant effects on energy metabolism and possibly nocturnal arousal and sleep fragmentation. However, there were no detectable long term effects of our treatments on SIVIR, suggesting that these effects are only short-lived, in order to maintain homeostasis in the short term. (c) 2008 Elsevier Inc. All rights reserve
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