Climate warming causes the advancement of spring arrival of many migrant birds breeding in Europe, but the effects on their autumn migration are less known. We aimed to determine any changes in the ...timing of Song Thrush captured during spring and autumn migrations at the Polish Baltic coast from 1975 to 2014, and if these were related to long-term changes of temperature at their breeding grounds and migration routes. The timing of spring migration at Hel ringing station in 1975–2014 did not show long-term advance, but they had responded to environmental conditions on the year-to-year basis. The warmer the temperatures were in April on their migration route, the earlier were the dates of the median and the end of spring migration at Hel. The beginning of autumn migration at the Mierzeja Wiślana ringing station advanced by 5 days between 1975 and 2014. The warmer the April on route, and the July at the Song Thrushes’ breeding grounds, the earlier young birds began autumn migration across the Baltic coast. We suggest this was a combined effect of adults’ migration and breeding early during warm springs and young birds getting ready faster for autumn migration during warm summers. The average time span of 90% of the autumn migration was extended by 5 days, probably because of early migration of young birds from first broods and late of those from second broods enabled by warm springs and summers. The response of Song Thrushes’ migration timing to temperatures on route and at the breeding grounds indicated high plasticity in the species and suggested it might adapt well to climate changes.
The research problem undertaken in this study is to determine the scale of infection of Eurasian blue tit
and Great tit
and the biological diversity of their internal parasites, helminths. The aim of ...the study is to gain new knowledge about the structure of the helminth communities of the Eurasian blue tit and Great tit on the southern coast of the Baltic Sea during autumn migration to their wintering grounds. Helminths of tits were collected in 2008-2012 on the southern coast of the Baltic Sea in Poland. PAST v. 2.11 software was used for the calculations. Barcoding DNA was used to identify trematodes initially classified based on morphological characters to the genera
and
Cestodes
were recorded for the first time in Poland. The Eurasian blue tit is a new host in Poland for three species of helminths: cestode
and filarial nematodes,
and
. The Great tit is a new host in Poland for trematode
, cestode
and
and filarial nematode
The nematode
was the species most frequently recorded in both host species. A high degree of similarity was found between the component communities and infracommunities of helminths in Eurasian blue tit and Great tit. The new information provided in this study has increased our knowledge of the transmission of helminths in Central Europe.
We demonstrate a stack of two III-nitride laser diodes (LDs) interconnected by a tunnel junction grown by plasma-assisted molecular beam epitaxy. Hydrogen-free growth is used to obtain as-grown ...p-type conductivity essential for buried tunnel junctions (TJ). We show the impact of the design of tunnel junction. In particular, we show that, apart from the beneficial piezoelectric polarization inside the TJ, heavy doping reduces the differential resistivity even further. The device starts to lase at a wavelength of 459 nm with a slope efficiency (SE) of 0.7 W/A followed by lasing at 456 nm from the second active region doubling the total SE to 1.4 W/A. This demonstration opens new possibilities for the fabrication of stacks of ultraviolet and visible high power pulsed III-nitride LD.
The authors analysed how body mass, migration distance, taxonomic family and breeding on small islands vs. continents affect wing length in 72 species of closely related Old World reed and bush ...warblers (Acrocephalidae and Locustellidae), based on literature data. The species they analysed share similar morphology, habitat, food preferences, feeding habits and breeding systems, but their migratory behaviour varies from sedentariness to long-distance migration. The mean wing length of these species was strongly correlated with their body mass, migration distance and taxonomic family. The wing was on average 23.4% longer for each doubling ofbody mass and 2.7% longer for each 1,000 km of migration distance. Breeding on small islands was not significantly related to wing length. Species of Acrocephalidae had on average 11.7% longer wings than Locustellidae with the same body mass and migration distance. After they partly controlled for the effects of different habitats and behaviours, the results showed that at inter-specific level migration affects wing length in proportion to migration distance.
We present the electronic and structural properties of monolayer WSe2 grown by pulsed-laser deposition on monolayer graphene (MLG) on SiC. The spin splitting in the WSe2 valence band at K¯ was ...ΔSO=0.469±0.008 eV, as determined by angle-resolved photoemission spectroscopy. Synchrotron-based grazing-incidence in-plane x-ray diffraction (XRD) revealed the in-plane lattice constant of monolayer WSe2 to be aWSe2=3.2757±0.0008 Å. This indicates a lattice compression of −0.19% relative to bulk WSe2. By using the experimentally determined graphene lattice constant (aMLG=2.4575±0.0007 Å), we found that a 3×3 unit cell of the slightly compressed WSe2 is perfectly commensurate with a 4×4 graphene lattice with a mismatch below 0.03%, which could explain why the monolayer WSe2 is compressed on MLG. From XRD and first-principles calculations, we conclude that the observed size of strain will affect ΔSO only on the order of a few meV. In addition, angle-resolved, ultraviolet, and x-ray photoelectron spectroscopies shed light on the band alignment between WSe2 and MLG/SiC and indicate electron transfer from graphene to the WSe2 monolayer. As further revealed by atomic force microscopy, the WSe2 island size depends on the number of carbon layers on top of the SiC substrate. This suggests that the epitaxy of WSe2 favors the weak van der Waals interactions with graphene, while it is perturbed by the influence of the SiC substrate and its carbon buffer layer.
Greenshanks Tringa nebularia show various patterns of primary moult in the northern hemisphere, but farther south moult patterns are known only fragmentarily. We Identified geographical patterns in ...primary moult and pre-migratory fattening of Greenshanks on their southernmost African non-breeding grounds. We compared primary moult (using Underhill-Zucchini models) and body mass at a population level based on 356 Greenshanks caught in 1968–1998 at inland wetlands in Zimbabwe, and on the east and west coasts of South Africa. About 20% of immatures replaced one to five outer primaries in December—May, a rare pattern in the north. Sub-adults moulted all primaries on average 40 days earlier than adults, yet at the same rate. Adults started primary moult on average 16–19 days earlier in Zimbabwe and at the east coast than at the west coast (7, 4, 23 September, resp.). These dates correspond with the Greenshanks' broad-front arrival in Zimbabwe and the east coast, and their later arrival at the west coast. Moult took 10–17 days longer on average in Zimbabwe and at the east coast than at the west coast (122, 115, 105 days, resp.), thus the end of moult coincided within six days (31 December—6 January). Pre-migratory fattening began about 13–19 January across all regions. The mean departure fat loads of adults were 76 g In Zimbabwe, 116 g at the west coast and 125 g at the east coast. The heaviest adults from all three regions could reach the Nile Valley or the Red Sea coast in one non-stop flight. We suggest that Greenshanks at inland wetlands of Zimbabwe benefit from a shorter return migration distance and lower competition than at the coasts, and abundant food during the entire austral summer In favourable years, but can move on to the coasts if conditions deteriorate.
In this paper, we demonstrate a novel approach utilizing tunnel junction (TJ) to realize GaN-based distributed feedback (DFB) laser diodes (LDs). Thanks to the use of the TJ the top metal contact is ...moved to the side of the ridge and the DFB grating is placed directly on top of the ridge. The high refractive index contrast between air and GaN, together with the high overlap of optical mode with the grating, provides a high coupling coefficient. The demonstrated DFB LD operates at λ=450.15 nm with a side mode suppression ratio higher than 35dB. The results are compared to a standard Fabry-Perot LD.
In this paper the reliability of III-nitride blue laser diodes grown by plasma-assisted molecular beam epitaxy on low threading dislocation density Ammono-GaN substrates is studied. It is found that ...defects formed in the heavily Mg-doped electron blocking layer (EBL) strongly affect the lifetime of the devices. These defects are identified as basal stacking fault domains which create threading dislocations. The effect of the EBL growth conditions on their generation and influence on lifetime of devices is presented. By optimization of the growth conditions of the EBL the lifetime of III-nitride laser diodes has been increased from 2000 up to 100,000 h.
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