Mechanisms enabling individual recognition of passerine birds

Vokalizace umožňuje ptákům komunikovat na velké vzdálenosti nebo v prostředích, kde mohou být vizuální signály obtížně detekovatelné. Vokalizaci pěvců lze rozdělit na zpěv a volání. Zpěv může posluchače signálu informovat o druhové příslušnosti, pohlaví, kvalitě samce, agresivní motivaci a v neposlední řadě také identitě zpívajícího jedince. Rozpoznávání různých jedinců je velmi užitečná dovednost, která se běžně uplatňuje během teritoriálních interakcí mezi samci. Správná identifikace samců, kteří představují různě velkou hrozbu, umožňuje reagovat přiměřeně situaci a ušetřit energii nebo se vyhnout zranění z případného střetu. U řady druhů pěvců byla pomocí playbackových experimentů prokázána schopnost individuálního rozlišování založená na zpěvu, ale jen málokdy bylo odhaleno, podle čeho se rozpoznávají. Tato literární rešerše se zabývá problematikou neighbour-stranger experimentů, které zjišťují schopnost pěvců rozpoznávat mezi sousedy a cizími samci. Dále je zaměřena na struktury nebo vlastnosti zpěvu umožňující individuální rozpoznávání pěvců a jejich využití pro individuální akustický monitoring.Vocalization allows birds to communicate over long distances or in environments, where can be difficult to detect visual signals. Vocalization can be divided into songs and calls. Song may inform a listener of signal about species, sex, male quality, aggressive motivation and also about singer's identity. Recognition of different individuals is very valuable ability that is commonly used during territorial interactions among males. Correct identification of males, that pose different threat, enable to respond adequately to the situation and save energy or to avoid injury in potential conflict. The ability of individual distinguishing based on song was demonstrated by using playback experiments for many passerines, but it was rarely revealed the way of such identification. This review deals with the issue of neighbour-stranger experiments that confirm the ability of passerines to discriminate between neighbours and strangers. Further, it focus on structures or characteristics of birdsong enabling individual recognition of passerines and their possibly use for individual acoustic monitoring.Department of EcologyKatedra ekologiePřírodovědecká fakultaFaculty of Scienc

Collective topological spin dynamics in a correlated spin glass

The interplay between spin-orbit interaction (SOI) and magnetic order is currently one of the most active research fields in condensed matter physics and leading the search for materials with novel and tunable magnetic and spin properties. Here we report on a variety of unexpected and unique observations in thin multiferroic \Ge$_{1-x}$Mn$_x$Te films. The ferrimagnetic order in this ferroelectric semiconductor is found to reverse with current pulses six orders of magnitude lower as for typical spin-orbit torque systems. Upon a switching event, the magnetic order spreads coherently and collectively over macroscopic distances through a correlated spin-glass state. Lastly, we present a novel methodology to controllably harness this stochastic magnetization dynamics, allowing us to detect spatiotemporal nucleation of topological spin textures we term ``skyrmiverres''.Comment: 26 pages, 10 figures, 2 table

Energy scale of Dirac electrons in Cd3As2

Cadmium arsenide (Cd3As2) has recently became conspicuous in solid-state physics due to several reports proposing that it hosts a pair of symmetry-protected 3D Dirac cones. Despite vast investigations, a solid experimental insight into the band structure of this material is still missing. Here we fill one of the existing gaps in our understanding of Cd3As2, and based on our Landau-level spectroscopy study, we provide an estimate for the energy scale of 3D Dirac electrons in this system. We find that the appearance of such charge carriers is limited-contrary to a widespread belief in the solid-state community-to a relatively small energy scale (below 40 meV)

Frame of the lifting Cabin

Tato diplomová práce se zabývá konstrukčním návrhem rámu kabiny osobního výtahu o nosnosti 630kg (8 osob). Rychlost tohoto výtahu je 1ms-1. Součástí je výpočet provedený pomocí metody konečných prvků. Nosná konstrukce výtahu je analyzována pomocí programu I-DEASThis master thesis deal with design of elevator cabin frame. Working load of frame is 630 kg (8 people). Speed of elevator is 1m/s. This work also contains final element analysis of frame. Frame structure is analyzed by software I-DEAS.

Mechanisms enabling individual recognition of passerine birds

Vocalization allows birds to communicate over long distances or in environments, where can be difficult to detect visual signals. Vocalization can be divided into songs and calls. Song may inform a listener of signal about species, sex, male quality, aggressive motivation and also about singer's identity. Recognition of different individuals is very valuable ability that is commonly used during territorial interactions among males. Correct identification of males, that pose different threat, enable to respond adequately to the situation and save energy or to avoid injury in potential conflict. The ability of individual distinguishing based on song was demonstrated by using playback experiments for many passerines, but it was rarely revealed the way of such identification. This review deals with the issue of neighbour-stranger experiments that confirm the ability of passerines to discriminate between neighbours and strangers. Further, it focus on structures or characteristics of birdsong enabling individual recognition of passerines and their possibly use for individual acoustic monitoring

Mechanisms enabling individual recognition of passerine birds

Vocalization allows birds to communicate over long distances or in environments, where can be difficult to detect visual signals. Vocalization can be divided into songs and calls. Song may inform a listener of signal about species, sex, male quality, aggressive motivation and also about singer's identity. Recognition of different individuals is very valuable ability that is commonly used during territorial interactions among males. Correct identification of males, that pose different threat, enable to respond adequately to the situation and save energy or to avoid injury in potential conflict. The ability of individual distinguishing based on song was demonstrated by using playback experiments for many passerines, but it was rarely revealed the way of such identification. This review deals with the issue of neighbour-stranger experiments that confirm the ability of passerines to discriminate between neighbours and strangers. Further, it focus on structures or characteristics of birdsong enabling individual recognition of passerines and their possibly use for individual acoustic monitoring

Effect of Gd addition on the structural and magnetic properties of L10-FePt alloy thin films

The impact of Gd addition on the structural and magnetic properties of L10-FePt alloy thin films, which were sputter-deposited on MgO(001) substrates at 800C, was investigated. A rapid deterioration of L10 chemical ordering along with a strong amorphization effect is observed with addition of Gd. At more than 20 at. % Gd, additional crystalline phases occur. Due to the diminishing L10 chemical order, the perpendicular magnetic anisotropy (PMA) gets strongly reduced from about 3 down to 1 MJ/m3 with addition of 14 at. % Gd. For higher Gd concentrations, the easy axis of magnetization turns fully in-plane due to dominating magnetic shape anisotropy. Furthermore, the saturation magnetization gets reduced with Gd addition due to the antiferromagnetic coupling between the Fe and Gd magnetic moments. Also, the Curie temperature can be lowered. Interestingly, with addition of Gd, a change in film morphology takes place, changing from an isolated island structure to a more continuous film morphology, which is of particular interest for samples with low Gd concentra- tion as these films exhibit still strong PMA but rather low coercive fields

Příprava (001) preferenčně orientovaných titanových tenkých vrstev metodou iontového naprašování na termální oxid křemičitý

We propose the ion-beam sputtering deposition providing Ti thin films of desired crystallographic orientation and smooth surface morphology not obtainable with conventional deposition techniques such as magnetron sputtering and vacuum evaporation. The sputtering was provided by argon broad ion beams generated by a Kaufman ion-beam source. In order to achieve the optimal properties of thin film, we investigated the Ti thin films deposited on an amorphous thermal silicon dioxide using X-ray diffraction, and atomic force microscopy. We have optimized deposition conditions for growing of thin films with the only (001) preferential orientation of film crystallites, and achieved ultra-low surface roughness of 0.55 nm. The deposited films have been found to be stable upon annealing up to 300 °C which is often essential for envisaging subsequent deposition of piezoelectric AlN thin films.Práce se zabývá iontovým naprašováním titanových tenkých vrstev a studiem jejich krystalografie a drsnosti. Tyto parametry obvykle nejsou proveditelné konvenčními metodami magnetronového naprašování nebo vakuového napařování. Naprašování bylo realizováno pomocí Kaufmanova iontové zdroje. Nadeponované tenké vrstvy byly analyzovány pomocí XRD a AFM. Optimalizováním depozičních parametrů bylo dosaženo (001) preferenčně orientovaných krystalitů a velmi nízké drsnosti 0,55 nm. Teplotní stabilita titanových tenkých vrstev byla ověřena do 300 °C pro případné depozice nitridu hliníku, který pro dosažení požadovaných vlastností vyžaduje zahřívání substrátu při depozici