Theses (Faculty of Science and Technology)
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A DE Természettudományi és Technológiai Kar Tanácsának 2009. november 25.-i határozata alapján a jövőben elektronikus formában is elhelyezésre kerülnek a szakdolgozatok a Debreceni Egyetem Egyetemi és Nemzeti Könyvtár által működtetett egyetemi archívumban, a DEAba. A szakdolgozatok az archívumból kizárólag a Debreceni Egyetem IP-címeiről hozzáférhetőek, azokat nem lehet kinyomtatni, és azokból szövegrészeket nem lehet kiemelni.
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Megjelenítve 1 - 20 (Összesen 592)
Tétel Korlátozottan hozzáférhető Numerical and analytical investigation of the shape of Autler-Townes doublets in resonance ionizationAIT ELARABI, AYOUB; András Csehi; DE--Természettudományi és Technológiai Kar--Fizikai IntézetUnderstanding the behavior of quantum systems under external perturbations is fundamental in quantum mechanics and has numerous applications in fields such as spectroscopy and quantum computing. In this thesis, we investigate the phenomenon of Autler-Townes doublets in hydrogen atoms numerically, focusing on a three-level model. Autler-Townes doublets arise when a two-level quantum system, such as a hydrogen atom, is subjected to an external electromagnetic field, leading to the splitting of spectral lines due to the Autler-Townes effect. The study involves formulating and solving the population amplitude equations describing the time evolution of the hydrogen atom’s probability amplitudes under the influence of external fields. We employ the Range-Kutta method in MATLAB to numerically solve these equations and analyze the shape and characteristics of Autler-Townes doublets. Our simulations explore the influence of various parameters such as field strength and frequency on the doublet structure. Additionally, our research compares the numerical results obtained from the simulation with the three-level model solutions, providing insights into the dynamic interference and understanding the physical reasons for the modulations in the spectrum. Our findings not only contribute to the understanding of Autler-Townes doublets in hydrogen atoms but also shed light on potential applications in quantum technologies and spectroscopic techniques.Tétel Korlátozottan hozzáférhető Temporal Dynamics and Structural Composition of Macroinvertebrate Communities in Intermittent Lowland Streams of HungaryReyad, Abdulrahman; Nyeste, Krisztián; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetWe aimed to investigate whether there was time sharing of macroinvertebrate communities in our study streams during the wet phase (Q1 & H1). Furthermore, we explored whether there was dominance of specific groups and evenness within these communities (Q2 & H2). Also, if these communities exhibited homogenization during the wet phase. The study used a combination of field sample collection, laboratory sorting, and taxonomic identification to collect data on macroinvertebrate communities in different seasons and hydrological phases (flowing and pool phase). The study also used Ecological Quality Ratio (EQR), Evenness, Dominance, Richness, Abundance, and Shannon Index metrics to assess the ecological status and diversity of the streams. For the statistical analysis, we used the program R (please check the right name for the R) Q1: Does the community structure of macroinvertebrates in lowland streams exhibit temporal diversity? H1: Intermittent streams characterized by time-sharing communities also in the lowland. We detected time-sharing communities in lowland streams, but the Létai-ér showed the lowest sharing community. Furthermore, the study revealed significant dissimilarities (F=3.526, p=0.0001) by PERMANOVA pairwise comparisons among stream communities. However, PERMANOVA analysis did not reveal significant disparities in other metrics like dominance, Shannon diversity index, and Ecological Quality Ratio (EQR). Q2: Are the communities in our study streams taxonomically homogenized and characterized by the dominance of specific macroinvertebrate groups? H2: The communities in our study streams are not taxonomically homogenized but are characterized by the dominance of certain macroinvertebrate groups. We partially supported our hypothesis; we detected dominated communities but not in all streams; where the dominance was detected, it was continuously stable. For example, the Létai-ér had stable dominance and variable evenness, while Brassó-ér and Barát-ér showed fluctuations in both dominance and evenness. The taxonomically homogenized streams were not established because these streams changed between the dominated and homogenized communities within a year. Additionally in the dominated communities the Gastropoda was as the higher rate group, besides these the Coleoptera, Gastropoda exhibited the highest species richness. Crustacea, Gastropoda, and Coleoptera were also consistently detected in most of the sampling events. The study found that water level fluctuation influenced macroinvertebrate communities' evenness, diversity, and dominance in different streams and sampling events. In the sampling sites the “BAR” site had the highest EQR values and species diversity, while the “VID” site had the lowest. As the least drought waterbody was dominated, the intermittency plays a significant role in shaping the dynamics of macroinvertebrate communities, so the sampling period is important because the sampling events were shown varying metrics values. Replicates are needed to confirm the study results. This study explored the influence of the wet phase on the structure and diversity of macroinvertebrate communities in five lowland intermittent rivers (IS) in Hungary. The research aimed to address a knowledge gap in understanding the ecology and biodiversity of these ecosystems and to offer practical insights for their conservation and management and suggested that future research should focus on hydrological phases of these ecosystems including more sampling events and use adapted indices for IS.Tétel Korlátozottan hozzáférhető The possibility of Cladocera species mediation with chest wader: a case study during short distance walkingShahzadi, Irum; Csaba, Berta; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetDepending on the type of habitat, our samples contained different numbers of Cladocera species. Throughout our research, we identified ephippia and whole organisms in addition to the majority of the Cladocera remains. The remains of cladocerans are deposited in sediments after they die, and the boots are in contact with the sediment during the procedure of collecting the sample. Thus, to prevent incorrect data in the samples, a thorough cleaning procedure is required.Tétel Korlátozottan hozzáférhető Possible effects of cyanotoxins (cylindrospermopsin and microcystin) on the pigment and lipid production of the green alga Haematococcus lacustrisTatiana Siniakova, Tatiana; István Bácsi, István; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetThe eutrophication of freshwater ecosystems, primarily due to human activities, leads to the proliferation of harmful algae, particularly cyanobacteria. These cyanobacteria produce highly toxic metabolites, the cyanotoxins, which have diverse effects on biological activities in aquatic organisms, including eukaryotic algae. Our research aims to understand the possible impacts of cyanotoxins on resting stage formation and maturation of algae through the example of Haematococcus lacustris, which pigment composition changes serves as an indicator of the effects of stressors on the organism. We focused on the changes on pigment and lipid contents and composition induced under cylindrospermopsin (CYN) and microcystin-LR (MC-LR) containing cyanobacterial extract exposure and their effect in Haematococcus lacustris under laboratory conditions. Post-exposure, algal biomasses were lyophilized and resuspended in dimethyl sulfoxide (DMSO) for pigment extraction, and a chloroform-methanol mixture for lipid content measurement. Pigment and fatty acid compositions were analyzed using thin layer chromatography and instrumental analytical methods, respectively. Results showed a decline in carotenoid values with increasing MC-LR concentration, indicating potential disruption in carotenoid production mechanisms. A similar trend was observed with CYN exposure. These results suggest that cyanobacterial metabolites could have adverse effects on processes related to resting stage maturation, jeopardizing the survival of the population. These findings highlight the potential ecological implications of cyanotoxin effects on algae, paving the way for further research and mitigation strategies.Tétel Korlátozottan hozzáférhető Accumulation and translocation of metals in Sudan grass during a 3-month-long field experimentMunuhe, Esther; Tőzsér, Dávid; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetHeavy metal accumulation in plants is a critical aspect of phytoremediation strategies aimed at mitigating environmental pollution. A study was conducted in which we investigated the heavy metal accumulation in Sudan grass ((Sorghum bicolor (L.) Moench × Sorghum sudanense (Piper) cultivated in a contaminated area located in Lovász-zug. We monitored metal accumulation in the roots, stems and leaves to assess their remediation potential. Through analysis, we identified notable variations in the accumulation capacity of different metals within the plant organs with time. Based on the results obtained, our study concluded Sudan Grass as a tolerant plant species in soils with low to moderate levels of contamination. The main depository organ of Sudan grass is the root. It can be effectively utilized to phytoremediate heavy metal contaminated soils through extraction, stabilization and transfer processes in the plant organs. The findings prospects Sudan grass as a promising candidate for phytoremediation.Tétel Korlátozottan hozzáférhető Understanding the Role of Cladocera Species based on Subfossil Assemblages and Their Impact on Drying Period in Vekeri Lake, HungaryAHMAD KASMIRI, AFIFAH FAZA BINTI; Gyulai , István; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetThis study investigated the role of Cladocera species based on subfossil assemblages in Vekeri Lake, Hungary. The study of this aquatic ecosystem is pivotal to understanding the dynamics of freshwater environments and their responses to environmental changes. The primary objective of this study is to unravel the ecological significance of Cladocera species in Vekeri Lake. By examining subfossil assemblages preserved in the sediment core, we aim to identify Cladocera taxa present in different sediment layers. We look forward to assessing their abundance and diversity across time and investigate how Cladocera respond to the water level dluctuations during drying periods. We too aim to explore any potential implications for the lake’s limnological conditions. Through this interdisciplinary approach integrating hydrobiology, paleolimnology and climate science, this thesis aims to advance knowledge of how Cladocera species can serve as indicatior of ecological change in lakes facing drying seasons. Such insights are crucial for effective management and conservation of freshwater resources amidst a changing climate.Tétel Korlátozottan hozzáférhető Changes in water chemistry during cyanobacterial bloom mitigation with sodium percarbonateOmondi, Emmanuel; Bácsi , István; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetThis study assessed the efficacy of sodium percarbonate treatment in addressing cyanobacterial blooms and its impact on water chemistry dynamics in a fire water reservoir over a 50-day period. While the treatment had limited direct effects on water chemistry parameters, it effectively disrupted cyanobacterial biomass, leading to significant changes in nutrient concentrations, particularly inorganic nitrogen forms. Notably, alterations in conductivity and dominant anion concentrations were observed, indicating complex responses influenced by biological and chemical factors. Despite minimal effects on orthophosphate levels, sodium percarbonate emerges as a promising method for mitigating cyanobacterial blooms due to its ability to target cyanobacterial biomass while minimizing disruptions to overall water chemistry. Sodium percarbonate in the applied concentration had a significant effect only on conductivity and oxygen levels, the overall ecological impact was minimal. The treatment contributed to fluctuations in water chemistry, but environmental factors and biological processes largely influenced long-term trends.Tétel Korlátozottan hozzáférhető Investigating the genomic background of adaptation to salt stress in Saccharomyces cerevisiaeLiaqat, Huma; Pfliegler, Valter Péter; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetSaccharomyces cerevisiae is a model organism with widespread applications in baking and brewing. However, amid ongoing discussions concerning the probiotic viability and potential advantages or disadvantages, this study provides a comprehensive analysis of the adaptability and resilience of S. cerevisiae. We conducted an in vitro evolution experiment to investigate the genomic-scale responses of S. cerevisiae to osmotic stress caused by salinity, with a particular emphasis on genetic changes such as aneuploidies, point mutations, and loss of heterozygosity. The investigation reveals the intricate genetic strategies S. cerevisiae uses to resist salt stress, opening new avenues for potential uses. By examining the de novo mutations and genetic variants, our research contributes to the development of halo tolerant yeast strains. The resulting advancements, therefore, promise of innovative applications in areas like pharmaceuticals, saline wastewater treatment in agriculture, and the production of biodegradable plastics, among many others since this organism has the potential for flexibility in development in the future. The study not only helps understand adaptive strategies of yeast under environmental stress but highlights its utility for solving contemporary challenges across sectors.Tétel Korlátozottan hozzáférhető Evidence of behavioral contagion in captive black-and-white ruffed lemur (Varecia variegata variegata) and red ruffed lemur (Varecia rubra)Padilha Lemes, William; Nemeth, Zoltan; Amici, Federica; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetBehavioral contagion can be defined as the propensity to show a behavior after observing it displayed (i.e. trigger event) by another individual (i.e. model). This phenomenon, encompassing behaviors such as yawning and scratching, can have a significant role in social synchronization and coordination, and has been widely observed across various species, from birds to mammals. While contagious yawning and scratching have been extensively studied in monkeys and apes, limited research exists in lemur species. Here, we aimed to investigate the presence of contagious yawning and scratching in captive groups of black-and-white ruffed lemur (Varecia variegata variegata) and red ruffed lemur (Varecia rubra) housed at the Nyíregyházi Zoo, Hungary (N=8). Drawing on previous findings and hypotheses, we assessed the likelihood of yawning and scratching after observing a conspecific’s trigger event, and the possible mediating effect of the model’s dominance rank. Our results indicate a higher probability of other group members engaging in scratching and yawning behaviors after observing a trigger event, in both species. In contrast, our analysis did not reveal any mediating effect of the model’s dominance rank on the likelihood of response. This study sheds light on the presence and potential determinants of behavioral contagion in lemurs, contributing to our understanding about the phenomenon.Tétel Korlátozottan hozzáférhető DESIGN A 40 MVA DISTRIBUTION GRID FOR NAIROBI BY USING A NOVEL PROTECTIONMOHAMED , MOHAMED HASSAN; Kósa , Dr. János Árpád; DE--Természettudományi és Technológiai Kar--Fizikai IntézetThis project demonstrates the design of a 40 MVA power grid system for Nairobi. Efficient and reliable power supply systems continue to play a big role in the economic development of developing countries such as Kenya. In this project, I explore the history of the power grid from its early days to appreciate the significant steps modern grids have achieved. I discuss the underlying theories and principles surrounding power generation. I planned a novel protection for a grid by using superconducting material. I hope we can apply this method in Kenya regarding grid design. Lastly, I present the planned work with superconducting material.Tétel Korlátozottan hozzáférhető Possibility of Superconducting Protection for Grid in TürkiyeGür, Bülent Atacan; Kósa, János Árpád; DE--Természettudományi és Technológiai Kar--Fizikai IntézetIn my study, superconducting components for electric protection have been identified for Turkey's electrical grid. These include superconducting fault current limiters (SFCL), superconducting circuit breakers, and superconducting insulated cables. The selection of superconducting materials for grid protection was based on critical temperature, critical current density, and magnetic field characteristics. High-temperature superconductor YBCO was preferred for the created protection. The design was thought to be flexible to accommodate future technological advancements and meet grid needs.Tétel Korlátozottan hozzáférhető Design and Realization of a Control System for MicrocalorimeterAnwar, Saeed; Harasztosi, Lajos; DE--Természettudományi és Technológiai Kar--Fizikai IntézetIntroduction of Micro and Nano Calorimeters and their usage Design of Control Design of Electronics Building of Electronic System Operating the Control System Making Measurements with Whole SystemTétel Korlátozottan hozzáférhető COMPARATIVE ANALYSIS OF SOME LIPIDS IN VARIOUS TYPES OF MILKWangari, Veronicah; Csősz, Éva; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetAt present, there is strong research interest in the nutritional quality and health benefits of food, which is supported by public awareness and an ongoing desire to improve our quality of life. Consequently, targeted modification of the FA profile of milk fat is desirable. The data obtained in this study shows there are differences in the amount of examined lipids in different milk samples. The polyunsaturated fatty acids are found in fewer amounts compared to MUFA and SFAs. Especially in Cow milk, the PUFAs are in lower amounts compared to the rest. Though both n-3 PUFAs and n-6 PUFAs are generally considered to have beneficial health effects, a high omega-6 fatty acid intake, and a high omega-6/omega-3 ratio are associated with weight gain in both animal and human studies, whereas a high omega-3 fatty acid intake decreases the risk for weight gain.Tétel Korlátozottan hozzáférhető Relation between differentiability and monotonicity of real functionsIrin, Namira; Kiss, Tibor; DE--Természettudományi és Technológiai Kar--Matematikai IntézetThis thesis explores the intricate relationship between differentiability and monotonicity in real functions, two fundamental concepts in mathematical analysis. Differentiability, indicating the presence of a derivative at every point, and monotonicity, describing a function's consistent increase or decrease within an interval, are pivotal in understanding the behavior of functions across various domains of mathematics. This research seeks to deepen the theoretical understanding of these unique mathematical behaviors by investigating the conditions under which such functions exist and characterizing their properties through analytical methods.Tétel Korlátozottan hozzáférhető Interpolation of FunctionsBodaubyek, Aimuldir; Nagy, Gergő; DE--Természettudományi és Technológiai Kar--Matematikai IntézetThis thesis material shows how to estimate the values between given data points using polynomial interpolation, a key technique used in many scientific fields. We focus on the theoretical and practical aspects of polynomial interpolation, specifically Lagrange and Newton forms which are quite commonly used methods. By examining how these methods solve interpolation problems and minimize errors, we learned which method works best under different conditions. The results show that choosing the right interpolation method is crucial for accuracy, depending on the data's nature and the function being approximated. Overall, this study enhances our understanding of interpolation methods and their practical applications in real-world scenarios.Tétel Korlátozottan hozzáférhető Characterization of compact metric spaces in terms of Cantor setAhad, Abdul; Kiss, Tibor; DE--Természettudományi és Technológiai Kar--Matematikai IntézetThe Cantor set is a fundamental construct in mathematics that has been extensively studied for its interesting properties and applications in various fields. On the other hand, a metric space is a set together with a notion of distance between its elements, usually called points. Metric spaces are the most general setting used for understanding many of the concepts of mathematical analysis and geometry. The aim of this thesis is to explore the relationship between the Cantor set and compact metric spaces.Tétel Korlátozottan hozzáférhető Ecotoxicological Assessment of Antibiotics on Hydra oligactis SurvivalKontselidze, Asmat; Tökölyi, Jácint; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetThe impact of human activities on the environment's living organisms is increasing day by day. A prime example is the development of medicine and the pharmaceutical industry, which leads to various pharmaceuticals ending up in wastewater, including antibiotics, a widely used type. These ecotoxicological agents have been shown to cause many undesirable outcomes. In our study, we aimed to investigate the impact of one such widespread antibiotic, Trimethoprim (TMP), on the survival and microbiome composition of five different Hydra oligactis strains (C2/7, X11/14, M83/4, T3/2, T3/1). We tested six concentration groups (control, 0.1, 1, 10, 100, and 1000 µg/L). The results revealed that strains T3/1 and T3/2 were unaffected by antibiotics. However, strains C2/7 and M83/4 showed decreased survival at 1 µg/L. Conversly, strain X11/14 manifested increased survival at concentrations of 10 and 100 µg/L compared to the control group. While analysis of alpha and beta diversity did not reveal significant effects on hydra microbiomes, differential abundance analysis identified specific taxonomic groups affected by TMP. Overall, we observed high intraspecific variation, which is crucial for better understanding population dynamics in complex real environments.Tétel Korlátozottan hozzáférhető Revisiting the Taxonomic Identity of Pulsatilla bungeana var. astragalifolia in Mongolia: A Molecular Phylogenetic AnalysisAmalia, Lisa; Sramkó, Gábor; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetPulsatilla bungeana, an early spring flower species that is found widely in Eurasia shows intraspecific variation that has slightly different characteristics. However, unlike the widespread other variants, P. bungeana var. astragalifolia exhibits distinctive morphological features: purple anthers, broad and simply pinnate leaves, and undivided foliage. Its distribution also narrowed only to the Altai Mountain Regions of Mongolia. Additionally, the positioning of its stamen and styles that differ from the rest of the species, suggest a possible relation with an ancient lineage. This study aims to investigate whether this particular variant is part of P. bungeana or represents a truly different species. The reconstructed phylogenetic analysis using three gene regions (nrITS, accD-psaI, and trnL-F) revealed a clear separation between P. bungeana var. astragalifolia and most P. bungeana samples. The findings strongly suggest its classification as a new distinct species, Pulsatilla astragalifolia.Tétel Korlátozottan hozzáférhető EFFECTS OF TEMPERATURE VARIATION ON SPRINGTAILS FOLSOMIA CANDIDAMugisha, Joselyne; Barta, Zoltán; Lévai-Kiss, Johanna; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetOver the past five decades, human activities have resulted in the release of increasing amounts of carbon dioxide and other greenhouse gasses, contributing to global climate change through further warming of the atmosphere. The planet has warmed by around 0.85°C. This rise in temperature has been shown to significantly affect many organisms. In the context of climate change, it's not just a question of rising temperature, but also of various abnormal temperature fluctuations and, in some contexts, falling temperatures. In this particular experiment, we examined how temperature changes affect Folsomia candida springtails in their growth, reproduction and behavior. We selected adult individuals aged between 40 and 60 days. In total, we created twelve colonies, for three treatments and four colonies per treatment. These were: the optimal temperature, which we also took as a control group; the low-temperature treatment (10 °C); and a fluctuating one where temperature was randomly switched between the lower and the optimal ones. The results of the experiment showed that the F. candida springtails did indeed respond to temperature changes outside its optimal range. But responses are variable in the context of egg production, egg hatching and number of individuals. In colonies subjected to low temperatures, egg production was delayed. Overall, the low-temperature and random colonies showed no variation in mean individual size compared with the control colony. We found that temperature changes primarily affected egg production and hatching by delaying them, but also by reducing egg hatchability, most notably in cold temperatures (10°C) as well as random temperature colonies. Further studies are needed to examine the exact physiological and molecular reasons why hatching capacity and egg production are reduced at low temperatures and the specific adaptations that help springtails to deal with these changes.Tétel Korlátozottan hozzáférhető Why is it important that the business community give sustainability and environmental concerns top priority?Tiynkhan, Aidana; Viktor, Olah; DE--Természettudományi és Technológiai Kar--Biológiai és Ökológiai IntézetThis paper proposes logical reasons to explain why companies should prioritize sustainability and care about the environment. It aims to determine the impact of the business industry on the environment by using scientific reports and argues that being environmentally friendly is crucial for firms' survival in the long run. The government parties will inevitably take drastic measures against mass environmental destruction, leading to system change and alteration of business processes. Non-eco-friendly organizations may get swept away from the market. The paper presents three perspectives to support the argument: first, customers are increasingly opting for sustainable products; second, governments are taking aggressive measures to solve the climate crisis; and third, sustainable products and services are gaining significant market share. Therefore, businesses must prioritize environmental concerns not only to address emerging environmental issues but also for their future survival and prosperity. The paper will be written from an economic perspective, focusing on for-profit business organizations as the primary audience.