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Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.


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TL;DR: The largest stress response occurred during late incubation and was independent of sex, although males were in relatively poor condition and females in relatively good condition, and birds may be physiologically primed for extended fasts.
Abstract: We report the results of the first field study examining seasonal changes in corticosterone responses of typically long-lived birds of the order Procellariiformes. In particular, we examined whether grey-faced petrels Pterodroma macroptera gouldi showed changes in circulating baseline corticosterone concentrations and corticosterone responses to a standardized handling protocol across the breeding season. Such changes have been associated with changes in body condition and variations in energy demands on adult birds through the breeding season. During early incubation, males were in significantly better condition than females that had just completed laying, whereas during late incubation, males were in significantly poorer condition than females. In spite of these differences, there was no significant difference in baseline corticosterone concentrations between sexes or among birds at different reproductive stages. However, we detected significant differences in corticosterone responses associated with a standardized handling protocol at different stages through the breeding season. Responses were significantly greater during incubation compared with the prelay period and late chick rearing. Body condition was weakly and negatively correlated with maximum and total integrated corticosterone level, indicating that some of the individual variability in stress corticosterone responses could be explained by variation in body condition. However, the largest stress response occurred during late incubation and was independent of sex, although males were in relatively poor condition and females in relatively good condition. This period coincided with the breeding stage in which energy constraints on individual adults were higher than at other periods of the reproductive cycle and birds may be physiologically primed for extended fasts.

42 citations

Journal ArticleDOI
01 Jun 2020
TL;DR: Any age‐related change in the incubation period of COVID‐19, specifically any difference between older (aged ≥65 years) and younger adults is explored.
Abstract: Objective The aim of this study was to explore any age-related change in the incubation period of COVID-19, specifically any difference between older (aged ≥65 years) and younger adults. Methods Based on online data released officially by 21 Chinese cities from January 22 to February 15, 2020, the incubation period of COVID-19 patients who had travelled to Hubei was studied according to age. Previous studies were reviewed and compared. Results The study recruited 136 COVID-19 patients who had travelled to Hubei during January 5-31, 2020, stayed for 1-2 days, and returned with symptom onset during January 10-February 6, 2020. The median age was 50.5 years (range 1-86 years), and 22 patients (16.2%) were aged ≥65 years. The age-stratified incubation period was U-shaped with higher values at extremes of age. The median COVID-19 incubation period was 8.3 (90% confidence interval [CI], 7.4-9.2) days for all patients, 7.6 (90% CI, 6.7-8.6) days for younger adults, and 11.2 (90% CI, 9.0-13.5) days for older adults. The 5th/25th/75th/90th percentiles were 2.3/5.3/11.3/14.2 days for all, 2.0/5.0/10.5/13.2 days for younger adults, and 3.1/7.8/14.4/17.0 days for older adults. There were 11 published studies on COVID-19 incubation periods up to March 30, 2020, reporting means of 1.8-7.2 days, and medians of 4-7.5 days, but there was no specific study on the effect of age on incubation period. One study showed that severe COVID-19 cases, which included more elderly patients, had longer incubation periods. Conclusion Based on 136 patients with a travel history to Hubei, the epicenter of COVID-19, the COVID-19 incubation period was found to be longer in older adults. This finding has important implications for diagnosis, prevention, and control of COVID-19.

42 citations

Journal ArticleDOI
TL;DR: Scatchard analysis of usI-EGF binding to membrane preparations of five different human breast tumours found no evidence of non-specific binding to either EGF or receptor-bound ligand.
Abstract: FIGURE 1. Scatchard analysis of usI-EGF binding to membrane preparations of five different human breast tumours. membrane preparations, after addition of BSA to a final concentration of 0·1%, were incubated in a final volume of 130ilL for 16 h at 20°C with increasing concentrations of 123I-EGF (specific activity: 400 Ci/mmol; mouse EGF, receptor grade, Sigma, St Louis, USA; iodinated using Pro tag 125, Baker Fine Chemicals, Philipsburg, USA) ranging from 50 to 2500 pM in the absence and presence of a 100-fold excess nonlabeled EGF to correct for non-specific binding. For separation of free and receptor-bound ligand after the incubation of membrane preparations with 12sI_EGF, lOOIJL of the HAPsuspension at 4°C is added to each assay tube and incubation is performed for 30min at 4°C. During the incubation with HAP the tubes are shaken twice. Following this incubation, O'5mL of ice-cold buffer B (= buffer A, containing 0·1% bovine serum albumin: BSA, purified, Behringwerke AG, Marburg, West Germany) is Additional key phrases: breast tumour recurrence; tumour membranes; endocrine therapy; oestrogen receptors

42 citations

Journal ArticleDOI
TL;DR: Analysis of fresh eggs and newly hatched chicks confirmed that heavier eggs lost proportionately less water during incubation, suggesting that statistical relationships derived from interspecific comparisons of egg size and egg physiology are not generally applicable to studies of intraspecific egg-size variation.
Abstract: Egg size is commonly assumed to increase the fitness value of hatchlings, and yet, most intraspecific variation in egg size appears to be highly heritable. Because traits strongly associated with fitness are expected to have low heritabilities, these two observations are not mutually compatable unless other factors act to offset the fitness value of large eggs. In this paper, we assess the influence of intraspecific egg-size variation on incubation periods and rates of egg water loss among Japanese Quail (Coturnix japonica) eggs. In contrast to interspecific studies of these relationships, we observed very low correlations between the logarithms of fresh egg mass and incubation time (r2 = 0.016, P = 0.01, n = 378) and between fresh egg mass and daily water loss (r2 = 0.028, P = 0.03, n = 163). Analysis of fresh eggs and newly hatched chicks confirmed that heavier eggs lost proportionately less water during incubation. These observations suggest that statistical relationships derived from interspecific comparisons of egg size and egg physiology are not generally applicable to studies of intraspecific egg-size variation.

42 citations

Journal ArticleDOI
David Zadworny1, Kiyoshi Shimada1, Hiroyuki Ishida1, C. Sumi1, Koji Sato1 
TL;DR: The temporal changes between nutrient intake and plasma levels ofPRL at the start and end of incubation behavior suggested that changes in nutrient intake may not cause changes in the concentration of PRL, whereas the association between increased levels of PRl and decreased levels of estradiol suggested that they may be causally associated.

42 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023688
20221,316
2021104
2020123
2019136