Behaviour and reproductive success of female-female pairs of Ring-billed gulls (Larus delawarenis), Granite Island

Female-female pairs of Ring-billed Gulls were studied on Granite Island, northern Lake Superior, during the breeding seasons of 1979 and 1980. In 1979 the colony consisted of approximately 2400 pairs with 99 nests (4.1%) containing five to seven eggs. In 1980 the colony had increased in size to 2600 pairs and contained 71 (2.7%) superclutches. Extrapolating from superclutches in my observation areas, where all attendants were known, approximately 85% of the total ntmber of superclutches were attended by female-female pairs. The difficulty distinguishing these nests from those of polygynous groups laying in a single nest-cup or nests receiving dump eggs is discussed. Because of these difficulties, all superclutches were monitored and treated as a single sample. Eggs laid in superclutches were slightly smaller than those from normal clutches, but did not differ in shape. The incubation period differed significantly for eggs of the two clutch types, with eggs in superclutches taking Ionger to hatch than those in normal clutches. Ihis may be because the eggs toward the outside edge of nests containing superclutches received significantly less heat. Nests containing superclutches were larger than those containing normal clutches but were of similar quality and were not differentially located by substrate, density or colony location. Nearest neighbour distance was also similar for the two clutch types. Nest success did not differ significantly between superclutches and normal clutches. Hatching success for superclutches was 33% in 1979 and 29% in 1980, while normal clutches had 77% and 61% in 1979 and 1980, respectively. Significantly more eggs rolled from the nest or were destroyed or abandoned in superclutches compared to those from normal clutches. Egg fertility rates were 87% and 94% for eggs in superclutches while normal clutches had 100% and 99% fertility in the two years of study. Chicks from normal clutches had a significantly higher fledging success than those of superclutches. Chicks from the latter had a higher rate of mortality due mainly to a higher death rate during the week following hatching. During both years of my study chicks from superclutches hatched at significantly lighter weights than those from normal clutches, but their weights did not differ after the first week post hatch. Tarsal and culmen measurements followed a similar pattern to that of weight. Food types brought to chicks from the two clutch types did not differ. Their diet consisted almost totally of fish and insects. Females of female-female pairs were of normal size, weight, age and condition compared to heterosexually paired females. Levels of 13 blood chemistry parameters were measured for female-female pair members and heterosexually paired birds. The only consistent differences were low cholesterol and elevated progesterone levels in members of female-female pairs. Intra-pair size differences suggest that the females assertively paired by size. They exhibited mate fidelity and to a lesser extent nest-site tenacity. Behaviour of female-female pairs is compared to heterosexual pairs during courtship, the incubation period and rearing of the brood. Females involved in female-female pairs cooperated well. Four polygynous groups were monitored, and their behaviour and reproductive success is reported. Existing hypotheses regarding the origin(s) of female-female pairing and their biological significance are discussed

Validity of the Polar V800 heart rate monitor to measure RR intervals at rest

Purpose To assess the validity of RR intervals and short-term heart rate variability (HRV) data obtained from the Polar V800 heart rate monitor, in comparison to an electrocardiograph (ECG). Method Twenty participants completed an active orthostatic test using the V800 and ECG. An improved method for the identification and correction of RR intervals was employed prior to HRV analysis. Agreement of the data was assessed using intra-class correlation coefficients (ICC), Bland–Altman limits of agreement (LoA), and effect size (ES). Results A small number of errors were detected between ECG and Polar RR signal, with a combined error rate of 0.086 %. The RR intervals from ECG to V800 were significantly different, but with small ES for both supine corrected and standing corrected data (ES 0.999 for both supine and standing corrected intervals. When analysed with the same HRV software no significant differences were observed in any HRV parameters, for either supine or standing; the data displayed small bias and tight LoA, strong ICC (>0.99) and small ES (≤0.029). Conclusions The V800 improves over previous Polar models, with narrower LoA, stronger ICC and smaller ES for both the RR intervals and HRV parameters. The findings support the validity of the Polar V800 and its ability to produce RR interval recordings consistent with an ECG. In addition, HRV parameters derived from these recordings are also highly comparable

Theorizing piratical innovation: regulatory illegitimacy and firm growth

This article examines the growing phenomenon of firms in ‘winner takes all’ markets who adopt business models that prioritize exceptional levels of growth over other financial metrics. Often this growth results in firms breaking with regulatory norms, despite regulatory legitimacy being theorized as essential for resource acquisition in small firms. The article explores this apparent paradox. We propose piratical innovation as a firm level process built upon disrupting regulatory norms in a way that avoids negative legitimacy judgments. Extending labelling theory, we develop a conceptual model where piratical innovation blends a range of symbolic and substantive actions to enable these firms to maintain legitimacy amongst stakeholders, even when growth is underpinned by illegitimate acts. We conclude by considering the wider applicability of piratical innovation as a model for small firm growth, and the consequences for other firms which must compete against such innovations

Postexposure Treatment and Animal Rabies, Ontario, 1958-2000

This paper investigates the relationship between animal rabies and postexposure treatment (PET) in Ontario by examining the introduction of human diploid cell vaccine (HDCV) in 1980 and the initiation of an oral rabies vaccination program for wildlife in 1989. Introducing HDCV led to an immediate doubling of treatments. Both animal rabies and human treatments declined rapidly after the vaccination program was introduced, but human treatments have leveled off at approximately 1,000 per year

Elimination of Arctic Variant Rabies in Red Foxes, Metropolitan Toronto

To control the arctic variant of rabies virus in red foxes, 332,257 bait doses containing live, attenuated Evelyn-Rokitnicki-Abelseth rabies vaccine were distributed in greater metropolitan Toronto during 1989–1999. Human and pet contact with bait was minimal, and no adverse reactions to the vaccine were noted. Significantly fewer rabid foxes were found during the 17 years after fox baiting (5 cases during 1990–2006) than in the 17 years before (96 cases during 1973–1989). The last report of a rabid fox in metropolitan Toronto was in 1996 (reporting period through September 2006), which confirms that distributing oral rabies vaccine bait is a feasible tactic for the control of rabies in foxes in urban environments

Radium contamination in the area around Dalgety Bay

In this report, the Committee on Medical Aspects of Radiation in the Environment (COMARE) presents a comprehensive review of the radium contamination in the area around Dalgety Bay. This report covers the history of the site, the type and extent of the contamination, the recent investigations and the cancer epidemiology for the area. The report also considers the implications for other similarly contaminated sites

Patient radiation dose issues resulting from the use of CT in the UK

In this report, COMARE presents a comprehensive review of the radiation dose issues associated with CT scans in the UK. The implications of the increase in the numbers of CT scans in the UK are considered in the report, with focus on the number of younger patients undergoing CT scans, who have greater sensitivity to x-rays. The report provides an update on the radiation protection aspects of justification (balancing risk and benefit) and optimisation (balancing the risk from the radiation dose with the quality of the image)

Heart rate variability and soccer training: a case study

The aim of this study was to monitor changes in HRV indices of two players of the same soccer team during a training period. Training loads of each session of the 3-week period were monitored by means of the training impulses (TRIMP) method. Resting RR intervals at supine position were obtained at five moments over 3-week period. The HRV indices (SD1, SDNN, RMSSD and HF) followed similar inter-subject patterns. They had similar values at M1 and, from M2, these variables were greater in athlete 1 than in athlete 2. At M2 and M4, athlete 1 presented a parasympathetic rebound, especially in SD1, SDNN and RMSSD, whereas athlete 2 presented reduction of these indices. We can advance that indices of HRV can be useful to monitor the effects of soccer training/competitive loads on parasympathetic modulation, being sensitive to both individual characteristics and to periods of stress and recovery