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In this study conducted in southeastern Ontario, Canada, we manipulated the length of outer tail feathers (streamers) of male barn swallows (Hirundo rustica) shortly after they returned to four small breeding colonies in the spring. Both streamers on most males in these colonies were experimentally either lengthened or shortened by 20 mm and as a result 10 randomly chosen males of each category ha
In an experimental study in Denmark, it was previously found that male barn swallows (Hirundo rustica) with elongated tail streamers obtained an apparent fitness advantage through earlier pairing, an increased frequency of second clutches, and higher total reproductive success per season. In a parallel study of five barn swallow colonies in Ontario, Canada, we also found that elongated males paire
The evolution of intense begging by dependent nestling birds has recently been the subject of several theoretical papers. The interesting problem here is that nestlings should be able to communicate their nutritional status to parents in ways that are less costly energetically and less likely to attract predators. Thus, conspicuous begging behaviour is thought to have evolved as a result of either
Male Barn Swallows (Hirundo rustica) help their mates to incubate in North America but not in Europe. In this study, conducted at four colonies in southeastern Canada, males contributed an average of 9% of the total amount of incubation during daylight hours. The total percent of time that eggs were incubated (nest attentiveness) by both sexes declined through the day, largely due to a response to
In the Marsh Tit Parus palustris, breeding performance improved with the age of both the male and the female parent-older birds produced larger clutches earlier in the season. The effect of male age, however, was mainly due to a positive association with the age of the female. When the effect of laying date was accounted for, there was no additional effect of female age on clutch-size. However, pa
Starlings show considerable variation in egg mass among clutches. Mean clutch egg mass was highly repeatable for females, but few characteristics of females were found to relate to egg mass. Egg mass related weakly to female age, but female age only explained a small part of the variation. Hatchling mass was strongly correlated with egg mass, but body mass at 14 d of age was unrelated to egg mass.
A cross-fostering experiment demonstrated that tarsus length of European starlings (Sturnus vulgaris) was heritable. The tarsus length of the foster-parent had no effect. A full-sib resemblance analysis showed that sibs were much more similar in tarsus length than explained by heritability alone. This was partly due to an effect of female mating status on offspring tarsus length. When nestling gro
Thermal performance of five bicycle helmets was evaluated with a thermal manikin head with six zones. Evaluation was made with physical and virtual experimental methods. Ambient temperature maintained at 24 °C and surface temperature of the thermal manikin head was set to 34 °C. Experiments were performed for air velocities of 1.6 m/s and 6 m/s. Heat transfer (W) of four thermal zones was recorded
Recent advances in high-intensity laser-produced plasmas have demonstrated their potential as compact charge particle accelerators. Unlike conventional accelerators, transient quasi-static charge separation acceleration fields in laser produced plasmas are highly localized and orders of magnitude larger. Manipulating these ion accelerators, to convert the fast ions to neutral atoms with little cha
The need for sustainable agricultural systems, which for example enhance soil organic carbon (SOC) content, has increased the interest for management with reduced tillage. In this study we used a Swedish long-term (20 yrs.) systems experiment, including reduced tillage (harrowing 10 cm) and plowing (moldboard plow 0–20 cm) combined with three levels of nitrogen (N) fertilization. With this setup w
Snuff lesions were induced in 30 rats. Ten of the snuff-exposed rats were killed immediately after 13 months snuff exposure, as were the 10 control animals. Ten rats were killed 1 month and 10 rats 4 months after the snuff administration had ceased. The rats exposed to snuff for 13 months exhibited hyperplastic, hyperorthokeratotic epithelium with focal mild atypia, focal ulcerations and marked su
Lower-limb amputation was performed on 261 patients from a catchment population of 232,500 in 1984-1986, and 253 of the amputees were retrospectively followed up. In 241 cases amputation was performed because of threatening or manifest gangrene, 95 of them without preceding consultation with vascular surgeons. In 19 cases amputation followed thromboembolectomy. Of the 127 patients seen by vascular
An integrated approach is presented in this study to design electrical hubs combining optimization, multi-criterion assessment and decision making. Levelized Energy Cost (LEC), Initial Capital Cost (ICC), Grid Integration Level (GI), Levelized CO2 emission (LCO2), utilization of renewable energy, flexibility of the system, loss of load probability (LOLP) are considered as criteria used to assess t
Parasite proteases play key roles in several fundamental steps of the Plasmodium life cycle, including haemoglobin degradation, host cell invasion and parasite egress. Plasmodium exit from infected host cells appears to be mediated by a class of papain-like cysteine proteases called 'serine repeat antigens' (SERAs). A SERA subfamily, represented by Plasmodium falciparum SERA5, contains an atypical
Cysteine proteases mediate liberation of Plasmodium berghei merozoites from infected hepatocytes. In an attempt to identify the responsible parasite proteases, we screened the genome of P. berghei for cysteine protease-encoding genes. RT-PCR analyses revealed that transcription of four out of five P. berghei serine repeat antigen (PbSERA) genes was strongly upregulated in late liver stages briefly
Plasmodium berghei is the causative agent of rodent malaria and is widely used as a model system to study the liver stage of Plasmodium parasites. The entry of P. berghei sporozoites into hepatocytes has extensively been studied, but little is known about parasite-host interaction during later developmental stages of the intracellular parasite. Growth of the parasite far beyond the normal size of
