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Feet and talons are the most specialized predatory attributes of raptor morphology. As such, the hindlimb morphology of owls should reflect their dietary specialization. Owls' diet varies widely between species with only a subset of owl species preying predominantly on small mammals. We hypothesize that different owl species have varied hindlimb morphology, adapted to their main prey types, and that only dietary specialists will be distinguishable based on talon morphology (e.g. toe length, talon curvature and thickness, etc.). We used a sample of 63 specimens from 15 owl species to obtain a variety of measurements of hindlimb morphology. We then used a discriminant function analysis to investigate the degree of variation between species and diet groups in terms of their morphological measurements. Our results indicate that talon morphology is linked to prey type in the owl species studied. Insect specialists and small mammal specialists were characterized by a low talon curvature, whereas generalists presented a pronounced talon curvature. Fish specialists presented particularly thick and robust talons, and insect specialists showed lower digit strength than other owl species. These findings could help determine the diet of other owl species, particularly endangered species for which data on diet is often scarce. This study will also be very useful in future studies of the ecology of sympatric species, resource partitioning between species, or between sexes of the same species, and more generally to the evolution of owls. [ABSTRACT FROM AUTHOR]

Analysis of carbon ([sup.13]C/[sup.12]C) and nitrogen ([sup.15]N/[sup.14]N) stable isotope ratios (hereafter [delta][sup.13]C and [delta][sup.15]N, respectively) in animal tissues is a powerful tool in food-web studies. However, isotopic ratios of prey are not transmitted directly to a consumer, as a diet-tissue discrimination factor (denoted A) occurs between sources and consumer's tissues. An accurate assessment of the diet of a consumer with stable isotopes thus requires that the [DELTA][sup.13]C and [DELTA][sup.15]N of the studied species are known. Our aim was to establish [DELTA][sup.13]C and [DELTA][sup.15]N values in the Snowy Owl (Bubo scandiacus (L., 1758)). Moreover, we assessed the potential effect of ethanol preservation of blood samples on [delta][sup.13]C and [delta][sup.15]N values. We kept four captive adult Snowy Owls on a pure diet of mice for [greater than or equal to] 6 weeks. We then collected mouse muscle and blood samples from the owls and analyzed their [delta][sup.13]C and [delta][sup.15]N values. [DELTA][sup.13]C and [DELTA][sup.15]N values (mean [+ or -] SE) for owl blood were +0.3 [per thousand] [+ or -] 0.2 [per thousand] and +1.9 [per thousand] [+ or -] 0.1 [per thousand], respectively. These values are the first discrimination factors ever reported in Strigiformes and are lower, for [DELTA][sup.15]N, than those obtained in terrestrial carnivores and other bird species, including falcons. Preservation in ethanol did not significantly affect [delta][sup.13]C and [delta][sup.15]N values. L'analyse des ratios isotopiques de carbone ([sup.13]C/[sup.12]C) et d'azote ([sup.15]N/[sup.14]N) (symbolises par [delta][sup.13]C et [delta][sup.15]N respectivement) dans les tissus animaux est un outil puissant pour l' etude des reseaux trophiques. Cependant, les ratios isotopiques des proies ne sont pas transmis directement au consommateur et un facteur de discrimination (note [DELTA]) est observe entre les ratios des sources et ceux du consommateur. La determination exacte du regime alimentaire d'un consommateur a l'aide des isotopes stables demande donc une connaissance des [DELTA][sup.13]C et [DELTA][sup.15]N chez l'espece a l'etude. Notre objectif etait de determiner les valeurs de [DELTA][sup.13]C et [DELTA][sup.15]N chez le harfang des neiges (Bubo scandiacus (L., 1758)). De plus, nous voulions determiner l'impact potentiel de la conservation d'echantillons sanguins dans une solution d'ethanol 70 % sur les valeurs de [delta][sup.13]Cet [delta][sup.15]N. Nous avons garde quatre harfangs des neiges en captivite, nourris exclusivement de souris pendant [greater than or equal to] 6 semaines. Nous avons ensuite recolte des echantillons sanguins des oiseaux et des muscles de souris et nous avons determine leur signature de [delta][sup.13]C et de [delta][sup.15]N. Les valeurs de [DELTA][sup.13]C et [DELTA][sup.15]N (moyenne [+ or -] ES) du sang chez le harfang des neiges sont de +0,3 [per thousand] [+ or -] 0,2 [per thousand] et +1,9 [per thousand] [+ or -] 0,1 [per thousand], respectivement. Ces valeurs de discrimination sont les premieres rapportees a ce jour chez les strigiformes et elles sont plus faibles, pour l'azote, que celles observees chez les carnivores terrestres et d'autres especes d'oiseaux, incluant les faucons. La conservation des echantillons sanguins dans une solution d'ethanol 70 % n'as pas affecte significativement les valeurs de [delta][sup.13]C et de [delta][sup.15]N., Introduction Naturally occurring stable isotopes of carbon ([sup.13]C, [sup.12]C) and nitrogen ([sup.15]N, [sup.14]N) are present in every living organism and they occur under specific ratios (denoted [delta][sup.13]C and [delta][sup.15]N, respectively) [...]

At the La Grande hydroelectric complex located in northern Quebec, Canada, mercury concentrations were measured in over 25 000 fish as part of an ongoing environmental effects monitoring program. Five fish species were monitored over a 30-year period: the non-piscivorous lake whitefish (Coregonus clupeaformis) and longnose sucker (Catostomus catostomus) and the piscivorous northern pike (Esox lucius), walleye (Sander vitreus) and lake trout (Salvelinus namaycush). Total mercury concentrations were measured by standard cold vapour atomic absorption spectrophotometry. Fish population characteristics, such as fishing yields, growth rates and condition factors were also monitored over a 20-year period. In reservoirs, mercury concentrations in all species increased rapidly after impoundment, peaking after 5 to 9 years in non-piscivorous fishes, and after 9 to 11 years in piscivorous species, at levels 3 to 6 times those measured in surrounding natural lakes, then significantly and gradually declined. Concentrations in most species have returned to levels typical of natural lakes, 10 to 30 years after flooding. Despite such increases, the monitored fish showed no mercury-related ill effects at the population level. For most species, increases were observed in fishing yields (by factors ranging from 2 to over 20), in growth rates and in condition factors (for more than a decade). The fishing yield increase was highest for northern pike of the Robert-Bourassa Reservoir, for which the highest average mercury concentrations were measured (3.28 μg g-1 (ww) for 700-mm fish). The biological boom usually observed after reservoir impoundment, resulting from increased nutrients, may have prevented potential mercury-related ill effects.

Although many studies have documented the developmental trajectory of somatic traits in birds, few measure physiological traits, and even fewer document individual variation in developmental trajectory across ecological context. Hematological traits underlying aerobic capacity can be predictive of nestling survival, fledgling flight ability, and ultimately recruitment. This study aimed to assess individual variation in the developmental trajectory of two physiological traits that underlie aerobic capacity, hematocrit and hemoglobin concentration, in relation to somatic development and ecological context. Our study species, the American kestrel (Falco sparverius), is sexually dimorphic and therefore likely to show sexual variation in developmental trajectory and nestling maturity.Weused lay date, year, brood size, nestling sex ratio, and parental nest visit rate to assess ecological context. Although somatic traits showed similar trajectories across nestlings, developmental trajectory for hematocrit and hemoglobin concentration showed individual variation not previously documented. This individual variation in developmental change, or trajectory, for physiological traits could not be explained by somatic development, sex, parental nest visit rate, lay date, year, brood size, or nestling sex ratio. However, we did find higher final hemoglobin concentration in 2018 and in nests with earlier lay dates. These findings demonstrate the importance of assessing physiological traits that capture aspects of individual quality distinct from somatic traits. Future studies are needed to understand the causes of individual variation in developmental trajectory, which cannot be explained by the ecological variables presented here, and the potential fitness consequences of this variation. [ABSTRACT FROM AUTHOR]

Predator–prey interactions can control population fluctuations of several terrestrial vertebrates and energy fluxes in food webs. Quantifying these interactions typically requires the number of prey consumed by predators to be known, but prey size is often ignored. We hypothesized that rodent mandibles, which are routinely found in predatory bird pellets and mammalian scats, could be used to accurately determine prey size and thus estimate biomass consumed by Arctic predators. We used 1863 lemmings and voles from museum and field specimens collected across the North American Arctic to relate three measurements of the dentary bone and one on the molar toothrow with individual body mass. When species and location of specimens are known, our results suggest that the body mass of small rodents can be estimated with high precision using the dentary bone measurements (average R2 ranging from 0.73 to 0.81), especially for lemmings and Microtus voles. Body mass can also be estimated with reasonable precision using the dentary bone measurements even when species or location was unknown (0.71 ≤ R2 ≤ 0.80). Equations to convert mandible size to body mass are provided for site‐ and species‐specific estimations. Geographic variations in the relationship between mandible size and body mass were found, suggesting potential effects of genetic isolation or interactions with the immediate environment on size. Using mandible measurements in prey remains allows more precise estimation of biomass consumed by predators, which is essential to quantify energy fluxes within ecosystems and examine resource partitioning among Arctic predators. [ABSTRACT FROM AUTHOR]

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A valence isoelectronic and isostructural series of charged bis(N-heterocyclic carbene) pincer complexes [M(bC^N^bC)X]OTf and [M(bC^N^bC)CH3CN](OTf)2 (where M = Ni, Pd, and Pt, bC^N^bC = 1,1′-(pyridine-2,6-diylbis(methylene))bis(3-butylbenzo[d]imidazol-2-ylidene)) were synthesized, characterized, modelled by density functional theory calculations, and compared for their electrochemical properties and reactivity with CO2. Although the electrochemical response of each complex is altered by the presence of CO2, controlled potential electrolysis experiments demonstrated the superior ability of [Pd] to reduce CO2 to CO in faradaic efficiencies up to 58% in the presence of trifluoroacetic acid, compared to [Pt] and [Ni] which showed only marginal production of CO, giving the trend [Pd] > [Pt] ＞ [Ni] for this series. [ABSTRACT FROM AUTHOR]

Reasons for performing study: Skin trauma in horses often leads to the development of chronic nonhealing wounds that lack a keratinocyte cover, vital for healing. Reports in mouse and man confirm the possibility of generating functional keratinocytes from induced pluripotent stem cells (iPSC), thus presenting myriad potential applications for wound management or treatment of skin disease. Similarly, differentiation of equine iPSC (eiPSC) into a keratinocyte lineage should provide opportunities for the advancement of veterinary regenerative medicine. Objectives: The purpose of this study was to develop an efficient method for the differentiation of eiPSC into a keratinocyte lineage. It was hypothesised that eiPSC can form differentiated keratinocytes (eiPSC-KC) comparable with primary equine keratinocytes (PEK) in their morphological and functional characteristics. Study design: Experimental in vitro study. Methods: Equine iPSC established using a nonviral system were treated for 30 days with retinoic acid and bone morphogenetic protein-4 to induce directed differentiation into iPSC-KC. Temporospatial gene and protein expression by eiPSC-KC was measured at weekly intervals of differentiation and in response to calcium switch. Proliferative and migratory capacities of eiPSC-KC were compared with those of PEK. Results: Equine iPSC, upon directed differentiation, showed loss of pluripotency genes and progressive increase in pancytokeratin expression indicating ectodermal specification into keratinocytes. High differentiation efficiency was achieved, with 82.5% of eiPSC expressing keratin 14, a marker of epidermal-specific basal stem cells, after 30 days of directed differentiation. Moreover, the proliferative capacity of eiPSC-KC was superior, while the migratory capacity (measured as the ability to epithelise in vitro wounds) was comparable with that of PEK. Conclusions: This proof of concept study suggests that eiPSC can successfully be differentiated into equine keratinocytes (eiPSC-KC) with features that are promising to the development of a stem cell-based skin construct, with the potential to regenerate lost or damaged skin. [ABSTRACT FROM AUTHOR]

To assess maternal and fetal outcome of pregnancy in patients with congenitally corrected transposition of the great arteries, we reviewed 19 patients (18 retrospectively) who had 45 pregnancies. Their ages ranged from 18 to 40 years (mean 27) at the time of pregnancy. Thirty-six percent of the pregnancies were undertaken while patients were cyanosed, 7% in patients with unpaced complete heart block, and 16% were undertaken after surgical repair of the associated anomalies. Change in functional class and maternal cardiovascular complications during pregnancy were analyzed as well as number of live births, miscarriages, elective termination of pregnancies, timing of delivery, and incidence of cardiac defects in the live offspring. Five patients (26% of patients) developed cardiovascular complications during pregnancy, namely congestive heart failure (3 patients), worsening cyanosis (1 patient), and cerebrovascular accident (1 patient). No maternal deaths occurred. There were 27 live births (60%), 12 miscarriages (27%), and 6 elective terminations of pregnancy (13%). Cyanosis was a significant risk factor for miscarriage. One live offspring had congenital heart disease. Close follow-up of these patients during pregnancy, by a team of experienced physicians, is recommended. [ABSTRACT FROM AUTHOR]

Contents Many of the developmental anomalies observed in cloned animals are related to foetal and placental overgrowth, a phenomenon known as the 'large offspring syndrome' (LOS) in ruminants. It has been hypothesized that the epigenetic control of imprinted genes, that is, genes that are expressed in a parental-specific manner, is at the root of LOS. Our recent research has focused on understanding epigenetic alterations to imprinted genes that are associated with assisted reproductive technologies (ART), such as early embryo in vitro culture (IVC) and somatic cell nuclear transfer (SCNT) in cattle. We have sought and identified single nucleotide polymorphisms in Bos indicus DNA useful for the analysis of parental-specific alleles and their respective transcripts in tissues from hybrid embryos derived by crossing Bos indicus and Bos taurus cattle. By analysing differentially methylated regions (DMRs) of imprinted genes SNRPN, H19 and the IGF2R in cattle, we demonstrated that there is a generalized hypomethylation of the imprinted allele and the biallelic expression of embryos produced by SCNT when compared to the methylation patterns observed in vivo (artificially inseminated). Together, these results indicate that imprinting marks are erased during the reprogramming of the somatic cell nucleus during early development, indicating that such epigenetic anomalies may play a key role in mortality and morbidity of cloned animals. [ABSTRACT FROM AUTHOR]

This integrative literature review is focused on (1) the prevalence of bone mineral density (BMD) decrements in children treated for acute lymphoblastic leukemia (ALL), and when these decrements are observed; (2) the risk factors associated with the development of decreased BMD and resultant complications in children treated for ALL; (3) the role, if any, that corticosteroids play in decreasing BMD in children treated for ALL; (4) interventions that can potentially manage bone loss in people treated for ALL during childhood or adolescence. The results showed that people who have been diagnosed with ALL can have decrements in BMD. The etiology of BMD decrements can be attributed to multiple factors including genetic endowment, lifestyle behaviors, the leukemia disease process, and treatment exposures especially to corticosteroids and cranial radiotherapy. Male gender, age greater than 10 years, and physical inactivity are associated with BMD decrements in ALL survivors. The role of pediatric oncology nurses in the management of bone disease in children with cancer across the illness trajectory is discussed. Copyright © 2005 by Association of Pediatric Oncology Nurses [ABSTRACT FROM AUTHOR]

We constructed ultraviolet (UV) photodetectors using thin films of silicon nanoparticles as active media. The Si nanoparticle films are electrodeposited at room temperature on Si p-type substrates. Uniform silicon nanoparticles of 1-nm diameter are dispersed from Si wafers using electrochemical etching. The nanoparticles are ultrabright under UV excitation, with nanosecond luminescence time characteristics. Current-voltage (I--V) characteristics indicate a photoconductor in series with a diode-like junction with a large enhancement in the forward current under UV illumination. Our results point to a sensitive UV detector with good visible blindness where the particle films effectively constitutes a wide-bandgap material. [ABSTRACT FROM PUBLISHER]