The relationship between environment, behavior, cognition, and the brain, in specialized food-caching chickadees (Poecile gambeli)

Environmental heterogeneity is known to affect phenotypic variation. Behavioral traits and the brain regions controlling these traits may be especially variable across environmental gradients as behavioral traits change rapidly in response to environment. Behavioral traits have been shown to differ across several environmental gradients of climatic harshness and novelty, such as latitudinal, elevational and urbanization gradients. This dissertation focuses on how cognition, behavior and the brain differ food-caching specialists inhabiting environments that differ in climatic harshness (i.e. differ in elevation) and novelty (i.e. differ in anthropogenic activity). I found that, chickadees from harsher high elevations, when compared with low elevation chickadees, have better problem-solving abilities and that these chickadees with better cognition are less willing to take risks when perceived predation risk is high, which resulted in a reduced investment in current offspring. I also found that chickadees from urban environments had a suite of generalist traits (e.g. more active in exploring a novel environment, better problem-solving abilities and larger brains) and some food-caching specialist traits (e.g. better long-term spatial memory retention) when compared with forest chickadees. This dissertation highlights that unique suites of behavioral traits are associated with different environments and suggests that a better understanding of how specific environmental factors affect specific (suites of) traits is necessary

Continuous and discrete models of cooperation in complex bacterial colonies

We study the effect of discreteness on various models for patterning in bacterial colonies. In a bacterial colony with branching pattern, there are discrete entities - bacteria - which are only two orders of magnitude smaller than the elements of the macroscopic pattern. We present two types of models. The first is the Communicating Walkers model, a hybrid model composed of both continuous fields and discrete entities - walkers, which are coarse-graining of the bacteria. Models of the second type are systems of reaction diffusion equations, where the branching of the pattern is due to non-constant diffusion coefficient of the bacterial field. The diffusion coefficient represents the effect of self-generated lubrication fluid on the bacterial movement. We implement the discreteness of the biological system by introducing a cutoff in the growth term at low bacterial densities. We demonstrate that the cutoff does not improve the models in any way. Its only effect is to decrease the effective surface tension of the front, making it more sensitive to anisotropy. We compare the models by introducing food chemotaxis and repulsive chemotactic signaling into the models. We find that the growth dynamics of the Communication Walkers model and the growth dynamics of the Non-Linear diffusion model are affected in the same manner. From such similarities and from the insensitivity of the Communication Walkers model to implicit anisotropy we conclude that the increased discreteness, introduced be the coarse-graining of the walkers, is small enough to be neglected.Comment: 16 pages, 10 figures in 13 gif files, to be published in proceeding of CMDS

Attractive instability of oppositely charged membranes induced by charge density fluctuations

We predict the conditions under which two oppositely charged membranes show a dynamic, attractive instability. Two layers with unequal charges of opposite sign can repel or be stable when in close proximity. However, dynamic charge density fluctuations can induce an attractive instability and thus facilitate fusion. We predict the dominant instability modes and timescales and show how these are controlled by the relative charge and membrane viscosities. These dynamic instabilities may be the precursors of membrane fusion in systems where artificial vesicles are engulfed by biological cells of opposite charge

Curvature-Induced Defect Unbinding in Toroidal Geometries

Toroidal templates such as vesicles with hexatic bond orientational order are discussed. The total energy including disclination charges is explicitly computed for hexatic order embedded in a toroidal geometry. Related results apply for tilt or nematic order on the torus in the one Frank constant approximation. Although there is no topological necessity for defects in the ground state, we find that excess disclination defects are nevertheless energetically favored for fat torii or moderate vesicle sizes. Some experimental consequences are discussed.Comment: 12 pages, 15 eps figure

The Effect of the Value Added Tax Changes on Public Budgets Revenue

Import 05/08/2014Cílem diplomové práce je zmapovat průběžný vývoj sazeb DPH od jejího zavedení do českého a slovenského daňového systému, zaznamenat důležité změny v tomto procesu a aplikovat vliv těchto změn na příjmovou stránku veřejných rozpočtů. Problematika daně z přidané hodnoty, především výše sazeb, je v České republice momentálně velice aktuální téma. Pro zpracování této práce jsou použity metody deskripce a analýzy, v menší míře také metoda komparace. Práce je z větší části teoretická, doplněná tabulkami a grafy pro lepší přehlednost. V rámci časových řad bylo zvoleno období od rozdělení Československa, tedy od roku 1993, až po současnost. Pozornost je upnuta především na státní rozpočty obou zemí. Závěrem můžeme tvrdit, že na rozpočtové příjmy v oblasti DPH mají krom zvyšování sazeb velký podíl také legislativní úpravy týkající se plátců daně, stanoveného limitu obratu či systému uplatňování nadměrných odpočtů. Každá změna může vést k výraznému ovlivnění celkového inkasa DPH, a proto je velmi důležité všechny tyto systému správně zkoordinovat.The aim of the thesis is to explore the continuous development of VAT rates since its introduction the Czech and Slovak tax system to record important changes in this process and apply the effect of these changes on public budgets revenue. The issue of value added tax, particularly the level of rates in the Czech Republic is very current topic. For this work are used to describe methods of description and analysis, partially the method of comparison. The work is largely theoretical, supplemented by tables and graphs for better clarity. Within the time series was selected from the split of Czechoslovakia, from 1993 to the present. Attention is clamped particularly at the national budgets of both countries. In conclusion we can say that the budget revenues in the VAT rate increase, furthermore, have a large share of a legislative adjustments relating to tax payers, the established limit turnover or the application of the overpayment. Any change can lead to significant impairment of general VAT collection, and therefore it is very important to all these properly coordinate system.156 - Katedra národohospodářskádobř

Dynamics of international tourism indicators

У статті розглянуто динаміку показників міжнародного туризму за період 2014 - 2017 рр. Наведено рейтинги лідерів серед країн світу за такими показниками, як кількість іноземних туристів, що відвідали країну, доходи від міжнародного туризму, витрати на міжнародний туризм, сальдо туристичного балансу. Було наведено зміну в пріоритетах відвідування серед країн лідерів за період 2014 - 2017 рр. Проаналізовано туристичний потенціал України, зокрема вивчено стан туристичної галузі в Україні за окремими показниками міжнародного туризму. Розглянуто динаміку туристичних потоків України, а саме виокремлені країни з яких за досліджуваний період приїжджала найбільша кількість в’їзних туристів до України. Наведено зміни у показниках міжнародного туризму в залежності від політичної стабільності та їх вплив на економіку країни. Обґрунтовано перспективи розвитку міжнародного туризму в Україні, наведено імовірні шляхи вирішення проблем галузі.The article discusses the dynamics of indicators of international tourism for the period 2014-2017. The ratings of leaders among the countries of the world are given in such indicators as the number of foreign tourists visiting the country, income from international tourism, expenditures on international tourism, and the tourist balance. The analysis of the change in the priorities of visits among the leaders of the countries for the period from 2014 to 2017 was made. It was analyzed the tourism potential of Ukraine, in particular, studied the state of the tourism industry in Ukraine according to some indicators of international tourism. Nowadays, international tourism is a developing industry. Unfortunately, in Ukraine, he is undergoing the ups and the downs. The unstable political and economic situation negatively influences the development of tourism in the country – both outbound and inbound tourism. According to the UNWTO in Ukraine in 2017, the arrival of foreign tourists was 14,2 million people, and in 2014 their number was 12,7 million people. Based on these data, we can conclude that the arrival of tourists has increased by almost 11,8 %. This insignificant growth negatively affects the development of tourism in the country. Accordingly, revenues from international tourism also decreased – in 2017 they amounted to 1,26 billion dollars, while in 2014 – 1,61 billion dollars. According to the tourism competitiveness index in 2017, Ukraine ranked 88th out of 136 analyzed countries. Ukraine has a huge potential for the development of tourism. Financing tourist destinations will lead to a positive result. One of the important processes is the establishment of a political situation in the country. Also, the stability of the economy is an important aspect in the development of tourism. With its advantageous geopolitical location, Ukraine has a great tourist and recreational potential, a favorable climate, world-class cultural and historical monuments and a rapidly developing tourism industry. The article deals with necessity of creating a clear mechanism for statistical observations in the field of tourism and develop a methodological basis for the correct analysis of tourism data in Ukraine

Polyhedral vesicles

Polyhedral vesicles with a large bending modulus of the membrane such as the gel phase lipid membrane were studied using a Brownian dynamics simulation. The vesicles exhibit various polyhedral morphologies such as tetrahedron and cube shapes. We clarified two types of line defects on the edges of the polyhedrons: cracks of both monolayers at the spontaneous curvature of monolayer $C_{\text {0}}<0$, and a crack of the inner monolayer at $C_{\text {0}}\ge0$. Around the latter defect, the inner monolayer curves positively. Our results suggested that the polyhedral morphology is controlled by $C_{\text {0}}$.Comment: 4 pages, 5 figure

A reaction-diffusion model for the growth of avascular tumor

A nutrient-limited model for avascular cancer growth including cell proliferation, motility and death is presented. The model qualitatively reproduces commonly observed morphologies for primary tumors, and the simulated patterns are characterized by its gyration radius, total number of cancer cells, and number of cells on tumor periphery. These very distinct morphological patterns follow Gompertz growth curves, but exhibit different scaling laws for their surfaces. Also, the simulated tumors incorporate a spatial structure composed of a central necrotic core, an inner rim of quiescent cells and a narrow outer shell of proliferating cells in agreement with biological data. Finally, our results indicate that the competition for nutrients among normal and cancer cells may be a determinant factor in generating papillary tumor morphology.Comment: 9 pages, 6 figures, to appear in PR