Incubation and Nest Building Behaviour of Black-Headed Gulls. I: Incubation Behaviour in the Incubation Period

Behaviour ◽  
1961 ◽  
Vol 18 (1-2) ◽  
pp. 62-105 ◽  
Author(s):  
C.G. Beer
Keyword(s):  
Incubation Period ◽  
Early Stage ◽  
Weather Conditions ◽  
Nest Material ◽  
Standard Pattern ◽  
Incubation Behaviour ◽  
Building Behaviour ◽  
Almost All ◽  
Incubation Pattern ◽  
Sitting Behaviour

AbstractI. Descriptions are given of the elements of the behaviour performed by Black-headed Gulls on the nest during the time between laying of the third egg and hatching of the first egg. 2. With three eggs in the nest it is found that the majority of settling sequences are complete, the majority of sitting spells are relatively long, and the eggs are covered for almost all of the available time. Also most of the relatively long sitting spells are preceded by complete settling sequences and most of the short sitting spells are preceded by incomplete settling sequences; most of the complete settling sequences lead to long sitting spells and most of the incomplete settling sequences lead to short sitting spells. 3. The frequency of settling, the proportion of complete settling sequences, and the total amount of time spent sitting, are used in comparing the behaviour in different situations. It is found that more or less than three eggs in the nest, eggs of abnormal shape or size, fixed eggs, disturbed nest material, scaring stimuli near the nest, presence of the mate, and the early stage of the sitting bout, produce incubation behaviour which differs from the standard pattern; the birds rise and settle more often, spend less total time sitting, and, with the exception of the last two cases, complete less of their settling sequences. On the other hand different times of day, different stages of the incubation period, differences in weather conditions, eggs of abnormal colour or markings were not associated with differences in the incubation pattern in my observations. 4. It is concluded that stimuli relayed from the brood-patches are particularly important in determining the pattern of settling and sitting behaviour. 5. Some problems connected with the use of the concepts of incubation "drive" and incubation "tendency" are discussed. 6. Stimuli to the feet and legs probably play a part in the release of shifting. 7. Quivering while sitting is probably stimulated by disturbed or "novel" contact between brood-patches and eggs.

Incubation and Nest-Building Behaviour of Black-Headed Gulls

Behaviour ◽  
1966 ◽  
Vol 26 (3-4) ◽  
pp. 189-214 ◽  
Author(s):  
C.G. Beer
Keyword(s):  
Incubation Period ◽  
Reproductive Season ◽  
Nest Building ◽  
External Control ◽  
Parental Behaviour ◽  
Incubation Behaviour ◽  
Building Behaviour ◽  
Natural Situation ◽  
Incubation Pattern

Abstract(1) Parental behaviour, and its development from incubation behaviour during the reproductive season, is described. (2) Day to day observations of the natural situation showed that elements of the incubation pattern persist throughout the post-hatching period but progressively decline in quantity, duration and completeness. (3) Substitution of eggs for chicks also showed that the readiness to show incubation responses in a standard incubation situation declines progressively during the post-hatching period. (4) A certain amount of experience with hatched chicks renders Black-headed Gulls incapable of immediately returning to sustained incubation behaviour if the conditions of the incubation period are restored. (5) Failure of the eggs to hatch results in extension of the incubation behaviour period beyond the normal time. (6) Premature introduction of hatched chicks in the nests of incubating gulls can cause the gulls to switch to parental behaviour and so end the incubation behaviour period before the normal time. (7) The timing of the change from incubation to parental behaviour is thus mainly a matter of external control. (8) Certain of the relationships found to hold between responses having an incubation function and responses having a nest-building function in the earlier phases also hold in the post-hatching period.

Incubation and Nest-Building Behaviour of Black-Headed Gulls Ii : Incubation Behaviour in the Laying Period

Behaviour ◽  
1962 ◽  
Vol 19 (4) ◽  
pp. 283-304 ◽  
Author(s):  
C.G. Beer
Keyword(s):  
Incubation Period ◽  
Progressive Increase ◽  
Functional Aspects ◽  
Incubation Behaviour ◽  
The Face ◽  
The Difference ◽  
The One ◽  
Building Behaviour ◽  
Two Stages ◽  
Sharp Corners

Abstract(i) Gulls in the laying period show incubation responses towards eggs in the nest but the pattern differs from the incubation pattern shown by gulls in the incubation period; the birds in the laying period rise and settle more often, complete relatively fewer of their settling sequences, sit for less of the available time, and the partners spend more time together on the territory. (ii) By adding two eggs to nests in the one-egg stage, and by comparing the behaviour of birds in the one-egg stage with birds with clutches of one egg in the incubation period, it is shown that part of the difference between the behaviour of birds in the laying period and birds in the incubation period can be attributed to the difference in clutch sizes but that this factor does not account for all the difference. (iii) Experiments with cylindrical models at the two stages of the laying period indicate that, at this time, the gulls are not as sensitive to the sharp corners of the models as they are in the incubation period; birds sitting or trying to sit on the oddly shaped "eggs" did not rise and resettle as often in the laying period as they did in the incubation period. (iv) It is suggested that during the laying period there is progressive increase in the tendency to sit on the nest and eggs coupled with increase in sensitivity to the shapes of the objects sat on. (v) The males perform more settlings and sit for more time than do the females during the laying period but both partners spend about equal amounts of time near the nest at this time. (vi) The proportion of eggs warm to the touch steadily increases during the laying period. (vii) Defeathering of the brood-patches progresses during the laying period. (viii) The tendency to return to the nest in the face of fear stimulation increases as the laying period advances. (ix) Increase in effective incubation during the laying period accounts for the differences between laying and hatching intervals. Functional aspects of this are discussed.

Resistance of cherry varieties to spring return frozes in the conditions of Astrakhan region

2020 ◽  
Author(s):  
A.A. Dronic A.A. ◽  
Keyword(s):  
Weather Conditions ◽  
Damage Score ◽  
The Stability ◽  
Almost All ◽  
Total Damage ◽  
Continental Climate ◽  
Unfavorable Weather

The article presents an assessment of the stability of introduced cherry varieties to spring return frosts in 2020 in the conditions of the sharply continental climate of the Astrakhan region. As a result of unfavorable weather conditions, the total damage score of all varieties was 2-5 points. Almost all the studied varieties showed an insufficient level of resistance to recurrent frosts.

scholarly journals Subcritical Transmission in the Early Stage of COVID-19 in Korea

2021 ◽  
Vol 18 (3) ◽  
pp. 1265
Author(s):  
Yong Sul Won ◽  
Jong-Hoon Kim ◽  
Chi Young Ahn ◽  
Hyojung Lee
Keyword(s):  
Incubation Period ◽  
Early Stage ◽  
Probability Distributions ◽  
Likelihood Estimation ◽  
Contact Tracing ◽  
Statistical Characterization ◽  
Serial Interval ◽  
Imported Cases ◽  
The Mean ◽  
Reporting Delays

While the coronavirus disease 2019 (COVID-19) outbreak has been ongoing in Korea since January 2020, there were limited transmissions during the early stages of the outbreak. In the present study, we aimed to provide a statistical characterization of COVID-19 transmissions that led to this small outbreak. We collated the individual data of the first 28 confirmed cases reported from 20 January to 10 February 2020. We estimated key epidemiological parameters such as reporting delay (i.e., time from symptom onset to confirmation), incubation period, and serial interval by fitting probability distributions to the data based on the maximum likelihood estimation. We also estimated the basic reproduction number (R0) using the renewal equation, which allows for the transmissibility to differ between imported and locally transmitted cases. There were 16 imported and 12 locally transmitted cases, and secondary transmissions per case were higher for the imported cases than the locally transmitted cases (nine vs. three cases). The mean reporting delays were estimated to be 6.76 days (95% CI: 4.53, 9.28) and 2.57 days (95% CI: 1.57, 4.23) for imported and locally transmitted cases, respectively. The mean incubation period was estimated to be 5.53 days (95% CI: 3.98, 8.09) and was shorter than the mean serial interval of 6.45 days (95% CI: 4.32, 9.65). The R0 was estimated to be 0.40 (95% CI: 0.16, 0.99), accounting for the local and imported cases. The fewer secondary cases and shorter reporting delays for the locally transmitted cases suggest that contact tracing of imported cases was effective at reducing further transmissions, which helped to keep R0 below one and the overall transmissions small.

Characteristics and attitudes of family planners in Khartoum, Sudan

1982 ◽  
Vol 14 (1) ◽  
pp. 7-16 ◽  
Author(s):  
M. A. Khalifa
Keyword(s):  
Family Planning ◽  
Birth Control ◽  
Early Stage ◽  
Significant Proportion ◽  
Large Family ◽  
Capital City ◽  
Age Group ◽  
African Countries ◽  
The Mean ◽  
Almost All

SummaryIn a survey of 1475 urban Moslem wives in the age group 15–49 living in the capital city of the Sudan, knowledge of birth control was reported by almost all respondents while a significant proportion had used contraception at least once. The mean age of the users was 32·8 years, their duration of marriage was 15·1 years and their mean number of surviving children was 4·6. Those who had never used contraception had a higher mean age, a longer duration of marriage and more surviving children. Most of the users had an urban residential background and belonged to the high socioeconomic class. They held favourable attitudes to family planning. Although they thought that having a large family (more than five children) was not desirable, their mean preferred family size was no different from that of the never users.The results indicate that contraception is used for the purpose of spacing births rather than limiting their ultimate number. At this early stage of contraceptive adoption in Sudan, the characteristics of the pioneer acceptors are similar to those observed in other African countries.

United Front: Partisans of the Leningrad Region and their connections with the Central Asian Soviet Republics

2021 ◽  
Vol 2021 (02) ◽  
pp. 214-225
Author(s):  
Sergey Kulik ◽  
Аnatoliy Kashevarov ◽  
Zamira Ishankhodjaeva
Keyword(s):  
World War Ii ◽  
Weather Conditions ◽  
Leningrad Region ◽  
World War ◽  
North West ◽  
The North ◽  
Occupied Territory ◽  
Central Asian ◽  
The Difference ◽  
Almost All

During World War II, representatives of almost all the Soviet Republics fought in partisan detachments in the occupied territory of the Leningrad Region. Among them were many representatives of the Central Asian republics: Kazakhstan, Kyrgyzstan and Uzbekistan. Many Leningrad citizens, including relatives of partisans, had been evacuated to Central Asia by that time. However, representatives of Asian workers’ collectives came to meet with the partisans. The huge distance, the difference in cultures and even completely different weather conditions did not become an obstacle to those patriots-Turkestanis who joined the resistance forces in the North-West of Russia.

Inverse changes in plasma prolactin and LH concentrations in female canaries after disruption and reinitiation of incubation

1984 ◽  
Vol 103 (2) ◽  
pp. 251-256 ◽  
Author(s):  
A. R. Goldsmith ◽  
S. Burke ◽  
J. M. Prosser
Keyword(s):  
Incubation Period ◽  
The Other ◽  
External Stimulus ◽  
Breeding Cycle ◽  
Plasma Prolactin ◽  
Incubation Behaviour ◽  
Incubating Birds ◽  
Egg Removal ◽  
Female Canaries

ABSTRACT Prolactin and LH concentrations were measured in the plasma of female canaries sampled during the breeding cycle and after disruption and reinitiation of incubation behaviour. The late incubation period was characterized by low LH and high prolactin concentrations, and canaries separated from their nests at this stage showed an increase in LH and a decline in prolactin within 3 h. In one experiment mean (±s.e.m.) concentrations before and 24 h after nest deprivation were: prolactin 397 ± 86 and 18 ± 5 μg/l; LH 1·04±0·21 and 2·03±0·17 μg/l. Female canaries which abandoned their nests after the eggs had been removed also showed an increase in LH together with a fall in prolactin 24 h after egg removal. When nest-deprived canaries were allowed to resume incubation, plasma prolactin increased again within 5 h and after 2 days had reached levels normal for incubating birds (398± 46 μg/l). Concentrations of LH changed more gradually but had decreased 2 days after the resumption of incubation. Thus prolactin and LH show inverse changes after the disruption and reinitiation of incubation behaviour; it is not clear, however, if the change in one is dependent on the other or if both hormones are responding to the same external stimulus. J. Endocr. (1984) 103, 251–256

Quality Assurance Methods Applied For Exposed-Aggregate Concrete Pavement Construction

2021 ◽  
Author(s):  
Adam Glinicki ◽  
Michal Glinicki
Keyword(s):  
Quality Assurance ◽  
Early Stage ◽  
Traffic Noise ◽  
Cost Effective ◽  
Weather Conditions ◽  
Special Treatment ◽  
Aggregate Concrete ◽  
Adverse Weather ◽  
Pavement Construction

The exposed aggregate pavement technology for construction of concrete highways is used in European countries, including Poland, mostly for heavy trafficked roads. It is mainly a two-lift slip-form technology with a special treatment of the top surface after the final smoothing operation. This is a demanding technology that leaves a little margin for mistakes. When properly done the pavement layer with exposed aggregates ensures designed skid resistance for vehicle wheels even in adverse weather conditions without excessive traffic noise. The challenge is to provide its cost-effective long term performance including both the adequate roughness and the desired smoothness of the pavement. The paper presents tools and methods for construction quality assurance specific for exposed aggregate concrete pavements. Required monitoring of the stability of concrete mix properties is discussed. The importance of concrete curing is analyzed in respect to the long term durability in wet-freeze regions with heavy use of deicing salts. Macrotexture assessment at the early stage of pavement construction is seen as the key factor for assurance of the proper skidding resistance. Local evaluation of smoothness is also a useful approach to assure the target IRI. Examples of quality assurance efforts applied on concrete highways recently constructed in Poland are presented.

scholarly journals City-Scale Distance Sensing via Bispectral Light Extinction in Bad Weather

2020 ◽  
Vol 12 (9) ◽  
pp. 1401
Author(s):  
Dong Zhao ◽  
Yuta Asano ◽  
Lin Gu ◽  
Imari Sato ◽  
Huixin Zhou
Keyword(s):  
Extinction Coefficient ◽  
Near Infrared ◽  
Imaging System ◽  
Weather Conditions ◽  
Light Extinction ◽  
Selection Strategy ◽  
Infrared Wavelengths ◽  
The Difference ◽  
Bad Weather ◽  
Almost All

In this paper, we propose a novel city-scale distance sensing algorithm based on atmosphere optics. The suspended particles, especially in bad weather, would attenuate the light at almost all wavelengths. Observing this fact and starting from the light scattering mechanism, we derive a bispectral distance sensing algorithm by leveraging the difference of extinction coefficient between two specifically selected near infrared wavelengths. The extinction coefficient of the atmosphere is related to both wavelength and meteorological conditions, also known as visibility, such as the fog and haze day. To account for different bad weather conditions, we explicitly introduce visibility into our algorithm by incorporating it into the calculation of extinction coefficient, making our algorithm simple yet effective. To capture the data, we build a bispectral imaging system that is able to take a pair of images with a monochrome camera and two narrow band-pass filters. We also present a wavelength selection strategy that allows us to accurately sense distance regardless of material reflectance and texture. Specifically, this strategy determines two distinct near infrared wavelengths by maximising the extinction coefficient difference while minimizing the influence of building’s reflectance variance. The experiments empirically validate our model and its practical performance on the distance sensing for the city-scale buildings.

scholarly journals Predicting SARS-CoV-2 Weather-Induced Seasonal Virulence from Atmospheric Air Enthalpy

2020 ◽  
Vol 17 (23) ◽  
pp. 9059
Author(s):  
Angelo Spena ◽  
Leonardo Palombi ◽  
Massimo Corcione ◽  
Alessandro Quintino ◽  
Mariachiara Carestia ◽  
...  
Keyword(s):  
Early Stage ◽  
Strong Relationship ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Specific Enthalpy ◽  
Atmospheric Air ◽  
Italian Provinces ◽  
The Relationship ◽  
Risk Scale ◽  
Correlating Equation

Following the coronavirus disease 2019 (COVID-19) pandemic, several studies have examined the possibility of correlating the virulence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, to the climatic conditions of the involved sites; however, inconclusive results have been generally obtained. Although neither air temperature nor humidity can be independently correlated with virus viability, a strong relationship between SARS-CoV-2 virulence and the specific enthalpy of moist air appears to exist, as confirmed by extensive data analysis. Given this framework, the present study involves a detailed investigation based on the first 20–30 days of the epidemic before public health interventions in 30 selected Italian provinces with rather different climates, here assumed as being representative of what happened in the country from North to South, of the relationship between COVID-19 distributions and the climatic conditions recorded at each site before the pandemic outbreak. Accordingly, a correlating equation between the incidence rate at the early stage of the epidemic and the foregoing average specific enthalpy of atmospheric air was developed, and an enthalpy-based seasonal virulence risk scale was proposed to predict the potential danger of COVID-19 outbreak due to the persistence of weather conditions favorable to SARS-CoV-2 viability. As an early detection tool, an unambiguous risk chart expressed in terms of coupled temperatures and relative humidity (RH) values was provided, showing that safer conditions occur in the case of higher RHs at the highest temperatures, and of lower RHs at the lowest temperatures. Despite the complex determinism and dynamics of the pandemic and the related caveats, the restriction of the study to its early stage allowed the proposed risk scale to result in agreement with the available infectivity data highlighted in the literature for a number of cities around the world.

Sign in / Sign up

Export Citation Format

Share Document