333 research outputs found
The emergence time and flight routes used by lesser horseshoe bats of Radziechowy colony (Poland)
Lesser horseshoes are bats quite strongly attached to their roost sites and are considered as sedentary species avoiding long-distance migration. In Poland, the range of occurrence of the lesser horseshoe bat is restricted to mountain areas, where they prefer overgrown mountain streams for their feeding grounds. Due to these features, even seemingly small habitat changes are likely to have serious implications for maintaining local subpopulations of this rare and endangered species. In Radziechowy village, where trees were cut in the Wieśnik stream (bat feeding area), a change in the use of feeding grounds by lesser horseshoe bats was observed. This publication additionally describes the time and the manner of departure of bats from their roost. The study was conducted before the logging (2012) and immediately after the logging (2013–2016), near a church, from the most beneficial point. The study was conducted by a team of 2–3 members, starting each time 15 minutes before sunset and finishing after the bats departure. Lesser horseshoe bats avoid light and open space and they leave their roost in a complicated way. It is established that there is a statistically significant correlation (r = 0.992, p < 0.001) between sunset and emergence time of bats from the roost site. In this paper, during the emergence time, the weather influence was observed. On a cloudy day, an earlier emergence time was observed — 9 minutes after the sunset, while the average emergence time for all observations was 23.3 minutes. The conducted detector watches proved that bats most likely use the closest environment of the colony within a radius of 150–200 meters. Lesser horseshoe bats were observed in ditches of roadside trees, dense hedges and backyard orchards overgrown with apples and pears, which is typical for this species.Підковики малі досить тісно пов’язані з місцями ночівлі і цей вид кажанів вважають осілим, що уникає дальні міграції. У Польщі ареал поширення підковика малого обмежений гірськими районами, де серед місць живлення надають перевагу зарослим гірським потокам. Завдяки цьому навіть незначні, на перший погляд, зміни біотопів можуть призвести до серйозних наслідків щодо підтримання локальних субпопуляцій цього рідкісного виду. У селі Радзехови, де уздовж потоку В’єшнік (місце живлення кажанів) вирубали дерева, виявлено зміни у використанні територій живлення та у появі кажанів із місць ночівлі. Дослідження проведено до (2012) та після (2013–2016) рубки дерев командою із 2–3 членів біля церкви з найбільш вигідної точки. Спостереження розпочали кожного разу за 15 хвилин до заходу сонця і закінчили після виходу кажанів. Підковики малі уникають світлі та відкриті місця і вони виходять з місця ночівлі складним способом. Визначено, що існує статистично вірогідна кореляція (r = 0,992, p < 0,001) між часом заходу сонця та появи кажанів із місця ночівлі. У цій роботі також розглянуто вплив погоди на час виходу кажанів. Зокрема, спостережено більш рання поява кажанів у похмурий день — за 9 хв після заходу сонця, при цьому середній час виходу за всі спостереження становив 23,3 хв. Проведені детекторні дослідження показали, що кажани використовують найближче оточення колонії у радіусі 150–200 метрів. Підковиків малих спостерігали у дуплах придорожніх дерев, густих живоплотах та садах з яблунею і грушею, що типово для цього виду
Diamonds as timing detectors for MIP: The HADES proton-beam monitor and start detectors
This paper gives an overview of a recent development of measuring time of
flight of minimum-ionizing particles (MIP) with mono-crystalline diamond
detectors. The application in the HADES spectrometer as well as test results
obtained with proton beams are discussed.Comment: submitted to Nuclear Instruments and Methods
Peierls Instabilities in Quasi-One-Dimensional Quantum Double-Well Chains
Peierls-type instabilities in quarter-filled () and half-filled
() quantum double-well hydrogen-bonded chain are investigated
analytically in the framework of two-stage orientational-tunnelling model with
additional inclusion of the interactions of protons with two different optical
phonon branches. It is shown that when the energy of proton-phonon coupling
becomes large, the system undergoes a transition to a various types of
insulator states. The influence of two different transport amplitudes on ground
states properties is studied. The results are compared with the pressure effect
experimental investigations in superprotonic systems and hydrogen halides at
low temperatures.Comment: 7 pages, RevTeX, 9 eps figure
Structural phase transitions and their influence on Cu+ mobility in superionic ferroelastic Cu6PS5I single crystals
The structural origin of Cu+ ions conductivity in Cu6PS5I single crystals is
described in terms of structural phase transitions studied by X-ray
diffraction, polarizing microscope and calorimetric measurements. Below the
phase transition at Tc=(144-169) K Cu6PS5I belongs to monoclinic, ferroelastic
phase, space group Cc. Above Tc crystal changes the symmetry to cubic
superstructure, space group F-43c (a=19.528); finally at 274K disordering of
the Cu+ ions increases the symmetry to F-43m, (a=9.794). The phase transition
at 274K coincides well with a strong anomaly in electrical conductivity
observed in the Arrhenius plot. Diffusion paths for Cu+ ions are evidenced by
means of the atomic displacement factors and split model. Influence of the
copper stechiometry on the Tc is also discussed.Comment: conference pape
Dielectric properties of BiFeO3 ceramics obtained from mechanochemically synthesized nanopowders
Dielectric behaviour of BiFeO3 ceramics,obtained by hot-pressing of nanopowders produced by mechanochemical synthesis from Bi2O3 and Fe2O3 oxides (weight ratio 2:1), was studied in the temperature range 125–575 K. The ceramics was found to exhibit step-like dielectric response ε*(T) with high permittivity values, similar to the behaviour of materials with giant dielectric permittivity. Three overlapping relaxation processes contribute to the dielectric response: i) relaxation in the lowtemperature range (220–420 K), characterized by activation energy of 0.4 eV, ii) relaxation in the temperature range 320–520 K with activation energy of 1.0 eV and iii) broad dielectric anomaly in the vicinity of 420 K, which disappears after 1 h annealing at 775 K. The lowtemperature relaxation is ascribed to the carrier hopping process between Fe2+ and Fe3+ ions. The presence of mixed valence of the Fe ions was proved by X-ray photoelectron spectroscopy. Dielectric relaxation in the middle-temperature range is considered as a result of grain boundary effect and internal barrier layers related to Bi25FeO40 phase as verified by X-ray diffraction. The high-temperature dielectric anomaly we relate to short-range hopping of ordered oxygen vacancies
Dielectric properties of BiFeO3 ceramics obtained from mechanochemically synthesized nanopowders
Dielectric behaviour of BiFeO3 ceramics,obtained by hot-pressing of nanopowders produced by mechanochemical synthesis from Bi2O3 and Fe2O3 oxides (weight ratio 2:1), was studied in the temperature range 125–575 K. The ceramics was found to exhibit step-like dielectric response ε*(T) with high permittivity values, similar to the behaviour of materials with giant dielectric permittivity. Three overlapping relaxation processes contribute to the dielectric response: i) relaxation in the lowtemperature range (220–420 K), characterized by activation energy of 0.4 eV, ii) relaxation in the temperature range 320–520 K with activation energy of 1.0 eV and iii) broad dielectric anomaly in the vicinity of 420 K, which disappears after 1 h annealing at 775 K. The lowtemperature relaxation is ascribed to the carrier hopping process between Fe2+ and Fe3+ ions. The presence of mixed valence of the Fe ions was proved by X-ray photoelectron spectroscopy. Dielectric relaxation in the middle-temperature range is considered as a result of grain boundary effect and internal barrier layers related to Bi25FeO40 phase as verified by X-ray diffraction. The high-temperature dielectric anomaly we relate to short-range hopping of ordered oxygen vacancies
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