11 research outputs found

    Orientation of native versus translocated juvenile lesser spotted eagles <i>(Clanga pomarina)</i> on the first autumn migration

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    The ontogeny of migration routines used by wild birds remains unresolved. Here we investigated the migratory orientation of juvenile lesser spotted eagles (LSE; Clanga pomarina) based on translocation and satellite tracking. Between 2004 and 2016, 85 second-hatched juveniles (Abels) were reared in captivity for release into the declining German population, including 50 birds that were translocated 940 km from Latvia. In 2009, we tracked 12 translocated juveniles, as well as eight native juveniles and nine native adults, to determine how inexperienced birds come to use strategic migration routes. Native juveniles departed around the same time as the adults and six of eight used the eastern flyway around the Mediterranean, which was used by all adults. In contrast, translocated juveniles departed on average 6 days before native LSEs, and five travelled southward and died in the central Mediterranean region. Consequently, fewer translocated juveniles (4/12) than native juveniles (7/8) reached Africa. We conclude that juvenile LSEs have a much better chance of learning the strategic southeastern flyway if they leave at an appropriate time to connect with experienced elders upon departure. It is not clear why translocated juveniles departed so early. Regardless, by the end of the year, most juveniles had perished, whether they were translocated (10/12) or not (6/8). The small number of surviving translocated juveniles thus still represents a significant increase in the annual productivity of the German LSE population in 2009

    Integration Of Sensor Orientation Data Into An Augmented Reality Technology

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    <p class="14AbstracttekstasAbstract"><span lang="EN-GB">Currently, such microelectromechanical sensors as accelerome­ters, gyroscopes and magnetometers are the dominant sensors in mobile devices. The market of mobile devices is constantly expanding and focused on sensor integration process by adding supplementary functionality for the applications; therefore, it is possible to adapt these sensors for augmented reality technology solutions. Many augmented reality solutions are based on computer vision processing methods in order to identify and track markers or other objects. However, the main problem is chaotic environment, lighting conditions where object recognition and tracking in real-time becomes difficult and sometimes is an impossible process. This paper analyses possibilities to apply microelectromechanical sensors. Additionally, it investigates quaternion use for sensor data to estimate reliable and accurate camera orientation and represent virtual content in augmented reality technology.</span></p

    Genetic differentiation and hybridization between greater and lesser spotted eagles (Accipitriformes : Aquila clanga, A-pomarina)

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    Greater and lesser spotted eagles (Aquila clanga, A. pomarina) are two closely related forest eagles overlapping in breeding range in east-central Europe. In recent years a number of mixed pairs have been observed, some of which fledged hybrid young. Here we use mitochondrial (control region) DNA sequences and AFLP markers to estimate genetic differentiation and possible gene flow between these species. In a sample of 83 individuals (61 pomarina, 20 clanga, 2 F1-hybrids) we found 30 mitochondrial haplotypes which, in a phylogenetic network, formed two distinct clusters differing on average by 3.0% sequence divergence. The two species were significantly differentiated both at the mitochondrial and nuclear (AFLP) genetic level. However, five individuals with pomarina phenotype possessed clanga-type mtDNA, suggesting occasional gene flow. Surprisingly, AFLP markers indicated that these "mismatched" birds (originating from Germany, E Poland and Latvia) were genetically intermediate between the samples of individuals in which mtDNA haplotype and phenotype agreed. This indicates that mismatched birds were either F1 or recent back-cross hybrids. Mitochondrial introgression was asymmetrical (no pomarina haplotype found in clanga so far), which may be due to assortative mating by size. Gene flow of nuclear markers was estimated to be about ten times stronger than for mtDNA, indicating a sex-bias in hybrid fertility in accordance with Haldane's rule. Hybridization between the two species may be more frequent and may occur much further west than hitherto assumed. This is supported by the recent discovery of a mixed pair producing at least one fledgling in NE Germany

    Basaltic lava domes, lava lakes, and volcanic segmentation on the southern East Pacific Rise

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    Meter-scale DSL-120 sonar mapping and coregistered Argo II photographic observations reveal changes in eruptive style that closely follow the third-order structural segmentation of the ridge axis on the southern East Pacific Rise, 17o11\u27-18o37\u27S. Near segment ends we observe abundant basaltic lava domes which average 20 rn in height and 200 rn in basal diameter and have pillow lava as the dominant lava morphology. The ubiquity of pillow lava suggests low effusion rate eruptions. The abundance of lava domes suggests that the fissure eruptions were of sufficient duration to focus and produce a line of volcanic edifices. Near segment centers we observe fewer but larger lava domes, voluminous drained and collapsed lava lakes, and smooth lobate and sheet lava flows with very little pillow lava. The abundance of sheet flows suggests that high effusion rate eruptions are common. Fewer lava domes and large lava lakes suggest that fissure eruptions do not focus to point sources. This pattern was observed on eight third-order ridge segments suggesting that a fundamental volcanic segmentation of the ridge occurs on this scale. The third-order segment boundaries also correlate with local maxima in the seismicaxial magmac hamber reflector depth throughout the study area and decreased across-axis width of the region of seismic layer 2A thickening along the one segment where sufficient cross-axis seismic lines exist. The geochemically defined magmatic segment boundaries in the study area match the locations of our volcanic segment boundaries, although rocks ampling density is not adequate to constrain the variation across all the third-order volcanic segments that we identify. These observations suggest that variation in the processes of crustal accretion along axis occurs at a length scale of tens of kilometers on superfast spreading (\u3e 140 km/Myr full rate) mid-ocean ridges

    Finite-State Text Processing

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