530 research outputs found

    Measurement of brood patch temperature of British passerines using an infrared thermometer

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    Capsule An infrared ear thermometer can be easily used to measure brood patch temperature in passerines caught on the nest or in mist-nets

    Opportunistic use of a wool-like artificial material as lining of Tit (Paridae) nests

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    The lining material is a key element of bird nests primarily serving as insulation for the adult, eggs and/or chicks but collection of such material will have an energetic cost. This study investigated the nest building effort of four species of tit (Paridae) in an English wood by determining the use of colored, wool-like artificial nest lining material over the period 2000-2010. The distances that birds carried the material from source to nest was recorded for each nest as an indirect measure of the energetic cost of collection of nest material by individual birds. Birds did not always use nest material from the nearest source to their nest and some birds collected material from 2, 3 or 4 well-separated sources. There was no detectable color preference in choice of material and few birds would travel more than 200 m to gather the material. Use of the material appeared to depend on the species. Within defined areas around material dispensers not all individual Great Tits (Parus major) used the artificial material and, for all species examined, the proportion of birds using the material declined with increasing distance between source and nest. Use of artificial material suggested that selection of nest materials was probably opportunistic but also reflected the preference of these species for a wool-like nest-lining

    Larval developmental temperature and ambient temperature affect copulation duration in a seed beetle

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    The effects of temperature on cellular, systemic and whole-organism processes can be short-term, acting within seconds or minutes of a temperature change, or long-term, acting across ontogenetic stages to affect an organism’s morphology, physiology and behavioural phenotype. Here we examine the effect of larval development temperature on adult copulatory behaviour in the bruchid beetle, Callosobruchus maculatus. As predicted by temperature’s kinetic effects, copulation duration was longest at the lowest ambient temperature. However, where ambient temperature was fixed and developmental temperature experimentally varied, males reared at the highest temperature were least likely to engage in copulation, whilst those reared at the lowest temperature copulated for longer. Previous research has shown males reared at cooler temperatures inseminate fewer sperm. Thus, in this species longer copulations are associated with reduced sperm transfer. We argue that knowledge of preceding ontogenetic conditions will help to elucidate the causes of variation in copulatory behaviour

    Pelvis morphology suggests that early Mesozoic birds were too heavy to contact incubate their egg

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    Numerous new fossils have driven an interest in reproduction of early birds, but direct evidence remains elusive. No Mesozoic avian eggs can be unambiguously assigned to a species, which hampers our understanding of the evolution of contact incubation, which is a defining feature of extant birds. Compared to living species, eggs of Mesozoic birds are relatively small, but whether the eggs of Mesozoic birds could actually have borne the weight of a breeding adult has not yet been investigated. We estimated maximal egg breadth for a range of Mesozoic avian taxa from the width of the pelvic canal defined by the pubic symphysis. Known elongation ratios of Mesozoic bird eggs allowed us to predict egg mass and hence the load mass an egg could endure before cracking. These values were compared to the predicted body masses of the adult birds based on skeletal remains. Based on 21 fossil species, we show that for nonornithothoracine birds body mass was 187% of the load mass of the eggs. For Enantiornithes, body mass was 127% greater than the egg load mass, but some early Cretaceous ornithuromorphs were 179% heavier than their eggs could support. Our indirect approach provides the best evidence yet that early birds could not have sat on their eggs without running the risk of causing damage. We suggest that contact incubation evolved comparatively late in birds

    The Araucaria Project: the Local Group Galaxy WLM--Distance and metallicity from quantitative spectroscopy of blue Supergiants

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    The quantitative analysis of low resolution spectra of A and B supergiants is used to determine a distance modulus of 24.99 +/- 0.10 mag (995 +/- 46 Kpc) to the Local Group galaxy WLM. The analysis yields stellar effective temperatures and gravities, which provide a distance through the Flux weighted Gravity--Luminosity Relationship (FGLR). Our distance is 0.07 mag larger than the most recent results based on Cepheids and the tip of the RGB. This difference is within the 1-sigma overlap of the typical uncertainties quoted in these photometric investigations. In addition, non-LTE spectral synthesis of the rich metal line spectra (mostly iron, chromium and titanium) of the A supergiants is carried out, which allows the determination of stellar metallicities. An average metallicity of -0.87 +/- 0.06 dex with respect to solar metallicity is found.Comment: 46 pages, 14 figures (2 low resolution color figures). Accepted for publication by Ap

    Incubation environment impacts the social cognition of adult lizards

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    Recent work exploring the relationship between early environmental conditions and cognition has shown that incubation environment can influence both brain anatomy and performance in simple operant tasks in young lizards. It is currently unknown how it impacts other, potentially more sophisticated, cognitive processes. Social-cognitive abilities, such as gaze following and social learning, are thought to be highly adaptive as they provide a short-cut to acquiring new information. Here, we investigated whether egg incubation temperature influenced two aspects of social cognition, gaze following and social learning in adult reptiles (Pogona vitticeps). Incubation temperature did not influence the gaze following ability of the bearded dragons; however, lizards incubated at colder temperatures were quicker at learning a social task and faster at completing that task. These results are the first to show that egg incubation temperature influences the social cognitive abilities of an oviparous reptile species and that it does so differentially depending on the task. Further, the results show that the effect of incubation environment was not ephemeral but lasted long into adulthood. It could thus have potential long-term effects on fitness

    Hospital food service: a comparative analysis of systems and introducing the ‘Steamplicity’ concept

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    Background Patient meals are an integral part of treatment hence the provision and consumption of a balanced diet, essential to aid recovery. A number of food service systems are used to provide meals and the Steamplicity concept has recently been introduced. This seeks, through the application of a static, extended choice menu, revised patient ordering procedures, new cooking processes and individual patient food heated/cooked at ward level, to address some of the current hospital food service concerns. The aim of this small-scale study, therefore, was to compare a cook-chill food service operation against Steamplicity. Specifically, the goals were to measure food intake and wastage at ward level; ‘stakeholders’ (i.e. patients, staff, etc.) satisfaction with both systems; and patients’ acceptability of the food provided. Method The study used both quantitative (self-completed patient questionnaires, n = 52) and qualitative methods (semi-structured interviews, n = 16) with appropriate stakeholders including medical and food service staff, patients and their visitors. Results Patients preferred the Steamplicity system overall and in particular in terms of food choice, ordering, delivery and food quality. Wastage was considerably less with the Steamplicity system, although care must be taken to ensure that poor operating procedures do not negate this advantage. When the total weight of food consumed in the ward at each meal is divided by the number of main courses served, at lunch, the mean intake with the cook-chill system was 202 g whilst that for the Steamplicity system was 282 g and for the evening meal, 226 g compared with 310 g. Conclusions The results of this small study suggest that Steamplicity is more acceptable to patients and encourages the consumption of larger portions. Further evaluation of the Steamplicity system is warranted. The purpose of this study was to directly compare selected aspects (food wastage at ward level; satisfaction with systems and food provided) of a traditional cook-chill food service operation against ‘Steamplicity’. Results indicate that patients preferred the ‘Steamplicty’ system in all areas: food choice, ordering, delivery, food quality and overall. Wastage was considerably less with the ‘Steamplicity’ system; although care must be taken to ensure that poor operating procedures do not negate this advantage. When the total weight of food consumed in the ward at each meal is divided by the number of main courses served, results show that at lunch, mean intake with the cook-chill system was 202g whilst that for the ‘Steamplicity’ system was 282g and for the evening meal, 226g compared with 310g

    Empirical modeling of the stellar spectrum of galaxies

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    An empirical method of modeling the stellar spectrum of galaxies is proposed, based on two successive applications of Principal Component Analysis (PCA). PCA is first applied to the newly available stellar library STELIB, supplemented by the J, H and Ks_{s} magnitudes taken mainly from the 2 Micron All Sky Survey (2MASS). Next the resultant eigen-spectra are used to fit the observed spectra of a sample of 1016 galaxies selected from the Sloan Digital Sky Survey Data Release One (SDSS DR1). PCA is again applied, to the fitted spectra to construct the eigen-spectra of galaxies with zero velocity dispersion. The first 9 galactic eigen-spectra so obtained are then used to model the stellar spectrum of the galaxies in SDSS DR1, and synchronously to estimate the stellar velocity dispersion, the spectral type, the near-infrared SED, and the average reddening. Extensive tests show that the spectra of different type galaxies can be modeled quite accurately using these eigen-spectra. The method can yield stellar velocity dispersion with accuracies better than 10%, for the spectra of typical S/N ratios in SDSS DR1.Comment: 34 pages with 18 figures, submitted to A

    Does the use of nest materials in a ground-nesting bird result from a compromise between the risk of egg overheating and camouflage?

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    Many studies addressing the use of nest materials by animals have focused on only one factor to explain its function. However, the consideration of more than one factor could explain the apparently maladaptive choice of nest materials that make nests conspicuous to predators. We experimentally tested whether there is a trade-off in the use of nest materials between the risks of egg predation versus protection from overheating. We studied the ground-nesting Kentish plover, Charadrius alexandrinus, in southern Spain. We added materials differing in thermal properties and coloration to the nests, thus affecting rates of egg heating, nest temperature and camouflage. Before these manipulations, adults selected materials that were lighter than the microhabitat, probably to buffer the risk of egg overheating. However, the adults did not keep the lightest experimental materials, probably because they reduced camouflage, and this could make the nests even more easily detectable to predators. In all nests, adults removed most of the experimental materials independently of their properties, so that egg camouflage returned to the original situation within a week of the experimental treatments. Although the thermal environment may affect the choice of nest materials by plovers, ambient temperatureswere not so high at our study site as to determine the acceptance of the lightest experimental materials

    Determination of the basic parameters of the dwarf nova EY Cygni

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    High-dispersion spectroscopy of EY Cyg obtained from data spanning twelve years show, for the first time, the radial velocity curves from both emission and absorption line systems, yielding semi-amplitudes K_{em}=24+/- 4 km s^-1 and K_{abs}=54+/- 2 km s^-1. The orbital period of this system is found to be 0.4593249(1)d. The masses of the stars, their mass ratio and their separation are found to be M_1 sin^3 i = 0.015+/-0.002 M_sun, M_2 sin^3 i = 0.007+/-0.002 M_sun, q = K_1/K_2 = M_2/M_1 = 0.44+/-0.02 and a sin i = 0.71+/-0.04 R_sun. We also found that the spectral type of the secondary star is around K0,consistent with an early determination by Kraft(1962). From the spectral type of the secondary star and simple comparisons with single main sequence stars, we conclude that the radius of the secondary star is about 30 per cent larger than a main sequence star of the same mass. We also present VRI CCD photometric observations, some of them simultaneous with the spectroscopic runs. The photometric data shows several light modulations, including a sinusoidal behaviour with twice the frequency of the orbital period, characteristic of the modulation coming from an elongated, irradiated secondary star. Low and high states during quiescence are also detected and discussed. From several constrains, we obtain tight limits for the inclination angle of the binary system between 13 and 15 degrees, with a best value of 14 degrees obtained from the sinusoidal light curve analysis. From the above results we derive masses M_1 = 1.10+/-0.09 M_sun, M_2 = 0.49+/-0.09 M_sun, and a binary separation a = 2.9+/- 0.1 R_sun.Comment: 14 pages, 14 figures, accepted for publication on A&
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