Exploring excitonic properties of vertically coupled semiconductor nanostructures using Path Integral Quantum Monte Carlo

In this thesis electron and exciton systems in atomistic model semiconductor nanostructures are theoretically studied using the Path Integral Quantum Monte Carlo (PI-QMC) technique. The application of this method gave us the opportunity to fully investigate Coulomb interacting systems at finite temperature, with an exact treatment of the impact of inter-particle correlations on the properties of a system without relying on complex trial functions or basis sets. Using confining potentials calculated from a strained atomistic model of semiconductor vertically stacked dot and ring nano-structures gave us insight into the ground state properties of vertically stacked quantum dot and ring systems, including the interplay between vertical electric and piezoelectric fields. Interactions between external electric fields, strain and piezoelectric potential revealed novel and unique for the stacked structures properties. The recombination rate of exciton (X) and bi-excitons (XX) as a function of structure vertical separation is investigated and compared against recombination in a multiple quantum dot, both with and without the application of an external electric field. The novel piezoelectric properties of stacked dots and rings in the presence of a vertical electric field, inducing in-plane charge probability distribution switching of an exciton, are explored. Results obtained from calculations of the lateral polarisability of X and XX indicates the possibility of experimental verification of this unique phenomenon

Fossil flora of Middle Jurassic Grojec clays (southern Poland). Raciborski’s original material reinvestigated and supplemented. I. Sphenophytes

Sphenopsid remains from Grojec clays (Grojec, Poręba, Mirów) collected and described by Raciborski in 1894 are re-examined for the first time and supplemented by Raciborski’s unpublished material housed at the Jagiellonian University (Institute of Botany) and by Stur’s preliminarily described material stored at the Geological Survey of Austria. Three species of Equisetum created by Raciborski (Equisetum renaulti, E. remotum, E. blandum) are now attributed to the common Jurassic species Equisetites lateralis, and the earlierundescribed Equisetites cf. columnaris is recognised. The occurrence of Neocalamites lehmannianus (originally described by Raciborski as Schizoneura hoerensis) has been confirmed from Grojec. The material that Raciborski referred to this species seems to be heterogeneous, and some specimens are now removed to the new proposed species Neocalamites grojecensis Jarzynka et Pacyna sp. nov. The new species is diagnosed by the following features: only a few prominent ribs present on shoot, leaf scars relatively large and ellipsoidal, numerous free leaves, vascular bundles alternate at node. Possibly the new species derives from Neocalamites lehmannianus or at least is closely related to it. Part of the poorly preserved remains can be determined only as Neocalamites sp. Another species created by Raciborski, Phyllotheca (?) leptoderma, is based on poorly preserved type specimens. Some of the unpublished specimens stored at the Jagiellonian University (Institute of Botany) correspond to Raciborski’s description, but considering the poor preservation of the original material and the not very realistic published illustrations of this species, they rather should be regarded as indeterminate cortical fragments of Neocalamites lehmannianus and/or badly preserved external cortical surfaces of the new species Neocalamites grojecensis. Phyllotheca (?) leptoderma should be considered a nomen dubium

Biological invasions in the aquatic ecosystems of Europe as a threat to biodiversity

In recent years biological invasions have become a serious ecological and socio-economic problem for many countries. Invasions are promoted by anthropogenic activity which is broadly understood as well as the instability of ecosystems. It carries a number of threats, often difficult to predict. The effects of invasion are long-term and occur on many levels of life. They can very often contribute to the extinction of native species, thus reducing biodiversity. According to the concept of sustainable development, the protection of biodiversity, and thus the prevention of biological invasions, is a necessary condition both to maintain the variety of nature, and to further the economic development of each country

Biological invasions in the aquatic ecosystems of Europe as a threat to biodiversity

In recent years biological invasions have become a serious ecological and socio-economic problem for many countries. Invasions are promoted by anthropogenic activity which is broadly understood as well as the instability of ecosystems. It carries a number of threats, often difficult to predict. The effects of invasion are long-term and occur on many levels of life. They can very often contribute to the extinction of native species, thus reducing biodiversity. According to the concept of sustainable development, the protection of biodiversity, and thus the prevention of biological invasions, is a necessary condition both to maintain the variety of nature, and to further the economic development of each country

Innovative Escapement-Based Mechanism for Micro-Antenna Boom Deployment

This paper presents the prototype of a tubular boom antenna developed for the Polish BRITE-PL satellite by the Space Research Center of the Polish Academy of Sciences (CBK PAN). What is unique about our work is that we developed an original type of the tubular boom antenna deployment mechanism that can be used widely as a basic solution for compact electrical antennas, booms deploying sensitive instruments, ultra-light planetary manipulators etc. The invented electromagnetic driving unit provides a dual complementary action - it adds extra energy to the driving spring, making the system more reliable, and at the same time it moderates the deployment speed acting as a kind of damper. That distinguishing feature predetermines the mechanism to be applied wherever the dynamic nature of a spring drive introducing dangerous vibrations and inducing severe local stress in the structure needs to be mitigated. Moreover, the paper reveals a product unique in Europe - a miniature beryllium bronze tubular boom free of geometry and strain defects, which is essential for stiffness and fatigue resistance. Both the deployment mechanism and the technology of tubular boom manufacturing are protected by patent rights

Fungal infection of cystic fibrosis patients — single center experience

INTRODUCTION: Cystic fibrosis (CF) is the most common monogenetic autosomal recessive disease in the human population. This systemic disease is characterized by changes in multiple organs, mainly in the lung tissue and digestive tract. More than 59% of CF patients become sensitized to fungal spores, mostly Aspergillus fumigatus. 5−15% of CF patients develop allergic bronchopulmonary aspergillosis. The aim of the study was to analyse the occurrence of yeast and filamentous fungi of the respiratory infections in CF patients and evaluation of drug resistance. MATERIAL AND METHODS: Between 2006 and 2014, mycological evaluation of 42 patients hospitalized at the National Institute of Tuberculosis and Lung Diseases was carried out. RESULTS: 217 specimens from pulmonary tract were collected from 42 patients with cystic fibrosis. 205 (68%) strains of yeast and 96 (32%) filamentous fungi strains were cultured. The most common mould strain was A. fumigatus — 22,2% (67 species). All isolates of filamentous fungi were in vitro 100% susceptible to itraconazole, voriconazole, posaconazole and amphotericin B. CONCLUSIONS: A. fumigatus and C. albicans were the most common etiological agents of fungal respiratory pathogens associated with CF patients. A. fumigatus strains were in vitro 100% susceptible to azole and amphotericin B. Two strains of C. albicans and one strain of C. tropicalis were non-susceptible to azole (fluconazole, itraconazole and voriconazole). Scedosporium apiospermum was resistant to amphotericin B (MIC > 32 mg/l) and susceptible to voriconazole (MIC 0.094 mg/l).INTRODUCTION: Cystic fibrosis (CF) is the most common monogenetic autosomal recessive disease in the human population. This systemic disease is characterized by changes in multiple organs, mainly in the lung tissue and digestive tract. More than 59% of CF patients become sensitized to fungal spores, mostly Aspergillus fumigatus. 5−15% of CF patients develop allergic bronchopulmonary aspergillosis. The aim of the study was to analyse the occurrence of yeast and filamentous fungi of the respiratory infections in CF patients and evaluation of drug resistance. MATERIAL AND METHODS: Between 2006 and 2014, mycological evaluation of 42 patients hospitalized at the National Institute of Tuberculosis and Lung Diseases was carried out. RESULTS: 217 specimens from pulmonary tract were collected from 42 patients with cystic fibrosis. 205 (68%) strains of yeast and 96 (32%) filamentous fungi strains were cultured. The most common mould strain was A. fumigatus — 22,2% (67 species). All isolates of filamentous fungi were in vitro 100% susceptible to itraconazole, voriconazole, posaconazole and amphotericin B. CONCLUSIONS: A. fumigatus and C. albicans were the most common etiological agents of fungal respiratory pathogens associated with CF patients. A. fumigatus strains were in vitro 100% susceptible to azole and amphotericin B. Two strains of C. albicans and one strain of C. tropicalis were non-susceptible to azole (fluconazole, itraconazole and voriconazole). Scedosporium apiospermum was resistant to amphotericin B (MIC > 32 mg/l) and susceptible to voriconazole (MIC 0.094 mg/l)

Palynological indicators of palaeoenvironmental perturbations in the Basque-Cantabrian Basin during the latest Cretaceous (Zumaia, northern Spain)

The latest Cretaceous palynological assemblages from the southern margin of the Basque-Cantabrian Basin (northern Spain, Zumaia) are dominated by black opaque equidimensional phytoclasts, black opaque blade shaped phytoclasts and translucent gold-orange to brown phytoclasts. Deep water dinoflagellate cysts Cannosphaeridium utinensis and Pterodinium spp. constitutes a part of the assemblages throughout the whole succession. This record and previous study suggest deposition of the Zumaia section in the marine bathyal conditions, in relative close proximity to the land. Palynofacies analyses yields increased abundance of Leiosphaeridia spp. and some changes in the palynomorph proportions just before the significant lithological change near the lower/upper Maastrichtian. This signal may either be primary and record an environmental change, or taphonomic. Nevertheless, environmental interpretation of the upper Maastrichtian palynological assemblage seems to be more consistent with the late Maastrichtian marine regression, and in consequence, a reduction of the distance from the nearby land. Such conditions may have caused transport of leiosphaerids from shallower water sites

European Jurassic floras : statistics and palaeoenvironmental proxies

The Jurassic floras of Europe show considerable diversity. To examine the extent of this diversity and its possible causes we used multivariate statistical methods (cluster analysis, PCA, NMDS) to compare all significant Jurassic floras in Europe. Data were based on 770 taxa from 46 fossiliferous occurrences (25 units) from France, Germany, Greenland, Hungary, Italy, Norway, Poland, Romania, Scotland, Serbia, Sweden, Switzerland, and the United Kingdom. Statistical analyses were applied at species level and genus level, and also performed for the major plant groups. The genus cladograms show affinities between different localities based on environmental factors, while the cladograms based on species affinities indicate only taxonomical correlations. The study shows that locality age does not seem to be of paramount importance for floral composition