58 resultados para adaptive capacity
Resumo:
Increased emissions of greenhouse gases into the atmosphere are causing an anthropogenic climate change. The resulting global warming challenges the ability of organisms to adapt to the new temperature conditions. However, warming is not the only major threat. In marine environments, dissolution of carbon dioxide from the atmosphere causes a decrease in surface water pH, the so called ocean acidification. The temperature and acidification effects can interact, and create even larger problems for the marine flora and fauna than either of the effects would cause alone. I have used Baltic calanoid copepods (crustacean zooplankton) as my research object and studied their growth and stress responses using climate predictions projected for the next century. I have studied both direct temperature and pH effects on copepods, and indirect effects via their food: the changing phytoplankton spring bloom composition and toxic cyanobacterium. The main aims of my thesis were: 1) to find out how warming and acidification combined with a toxic cyanobacterium affect copepod reproductive success (egg production, egg viability, egg hatching success, offspring development) and oxidative balance (antioxidant capacity, oxidative damage), and 2) to reveal the possible food quality effects of spring phytoplankton bloom composition dominated by diatoms or dinoflagellates on reproducing copepods (egg production, egg hatching, RNA:DNA ratio). The two copepod genera used, Acartia sp. and Eurytemora affinis are the dominating mesozooplankton taxa (0.2 – 2 mm) in my study area the Gulf of Finland. The 20°C temperature seems to be within the tolerance limits of Acartia spp., because copepods can adapt to the temperature phenotypically by adjusting their body size. Copepods are also able to tolerate a pH decrease of 0.4 from present values, but the combination of warm water and decreased pH causes problems for them. In my studies, the copepod oxidative balance was negatively influenced by the interaction of these two environmental factors, and egg and nauplii production were lower at 20°C and lower pH, than at 20°C and ambient pH. However, presence of toxic cyanobacterium Nodularia spumigena improved the copepod oxidative balance and helped to resist the environmental stress, in question. In addition, adaptive maternal effects seem to be an important adaptation mechanism in a changing environment, but it depends on the condition of the female copepod and her diet how much she can invest in her offspring. I did not find systematic food quality difference between diatoms and dinoflagellates. There are both good and bad diatom and dinoflagellate species. Instead, the dominating species in the phytoplankton bloom composition has a central role in determining the food quality, although copepods aim at obtaining as a balanced diet as possible by foraging on several species. If the dominating species is of poor quality it can cause stress when ingested, or lead to non-optimal foraging if rejected. My thesis demonstrates that climate change induced water temperature and pH changes can cause problems to Baltic Sea copepod communities. However, their resilience depends substantially on their diet, and therefore the response of phytoplankton to the environmental changes. As copepods are an important link in pelagic food webs, their future success can have far reaching consequences, for example on fish stocks.
Resumo:
T helper (Th) cells are vital regulators of the adaptive immune system. When activated by presentation of cognate antigen, Th cells demonstrate capacity to differentiate into functionally distinct effector cell subsets. The Th2 subset is required for protection against extracellular parasites, such as helminths, but is also closely linked to pathogenesis of asthma and allergies. The intracellular molecular signal transduction pathways regulating T helper cell subset differentiation are still incompletely known. Moreover, great majority of studies regarding Th2 differentiation have been conducted with mice models, while studies with human cells have been fewer in comparison. The goal of this thesis was to characterize molecular mechanisms promoting the development of Th2 phenotype, focusing specifically on human umbilical cord blood T cells as an experimental model. These primary cells, activated and differentiated to Th2 cells in vitro, were investigated by complementary system-wide approaches, targeting levels of mRNA, proteins, and lipid molecules. Specifically, the results indicated IL4-regulated recruitment of nuclear protein, and described novel components of the Th2-promoting STAT6 enhanceosome complex. Furthermore, the development of the activated effector cell phenotype was found to correlate with remodeling of the cellular lipidome. These findings will hopefully advance the understanding of human Th2 cell lineage commitment and development of Th2-associated disease states.
Resumo:
In ship and offshore terminal construction, welded cross sections are thick and the number of welds very high. Consequently, there are two aspects of great importance; cost and heat input. Reduction in the welding operation time decreases the costs of the work force and avoids excessive heat, preventing distortion and other weld defects. The need to increase productivity while using a single wire in the GMAW process has led to the use of a high current and voltage to improve the melting rate. Unfortunately, this also increases the heat input. Innovative GMAW processes, mostly implemented for sheet plate sections, have shown significant reduction in heat input (Q), low distortion and increase in welding speed. The aim of this study is to investigate adaptive pulsed GMAW processes and assess relevant applications in the high power range, considering possible benefits when welding thicker sections and high yield strength steel. The study experimentally tests the usability of adaptive welding processes and evaluates their effects on weld properties, penetration and shapes of the weld bead.The study first briefly reviews adaptive GMAW to evaluate different approaches and their applications and to identify benefits in adaptive pulsed. Experiments are then performed using Synergic Pulsed GMAW, WiseFusionTM and Synergic GMAW processes to weld a T-joint in a horizontal position (PB). The air gap between the parts ranges from 0 to 2.5 mm. The base materials are structural steel grade S355MC and filler material G3Si1. The experiment investigates heat input, mechanical properties and microstructure of the welded joint. Analysis of the literature reveals that different approaches have been suggested using advanced digital power sources with accurate waveform, current, voltage, and feedback control. In addition, studies have clearly indicated the efficiency of lower energy welding processes. Interest in the high power range is growing and a number of different approaches have been suggested. The welding experiments in this study reveal a significant reduction of heat input and a weld microstructure with the presence of acicular ferrite (AF) beneficial for resistance to crack propagation. The WiseFusion bead had higher dilution, due to the weld bead shape, and low defects. Adaptive pulse GMAW processes can be a favoured choice when welding structures with many welded joints. The total heat reduction mitigates residual stresses and the bead shape allows a higher amperage limit. The stability of the arc during the process is virtually spatter free and allows an increase in welding speed.
Resumo:
Alcohol consumption during pregnancy can potentially affect the developing fetus in devastating ways, leading to a range of physical, neurological, and behavioral alterations most accurately termed Fetal Alcohol Spectrum Disorders (FASD). Despite the fact that it is a preventable disorder, prenatal alcohol exposure today constitutes a leading cause of intellectual disability in the Western world. In Western countries where prevalence studies have been performed the rates of FASD exceed, for example, autism spectrum disorders, Down’s syndrome and cerebral palsy. In addition to the direct effects of alcohol, children and adolescents with FASD are often exposed to a double burden in life, as their neurological sequelae are accompanied by adverse living surroundings exposing them to further environmental risk. However, children with FASD today remain remarkably underdiagnosed by the health care system. This thesis forms part of a larger multinational research project, The Collaborative Initiative on Fetal Alcohol Spectrum Disorders (the CIFASD), initiated by the National Institute of Alcohol Abuse and Alcoholism (NIAAA) in the U.S.A. The general aim of the present thesis was to examine a cohort of children and adolescents growing up with fetal alcohol-related damage in Finland. The thesis consists of five studies with a broad focus on diagnosis, cognition, behavior, adaptation and brain metabolic alterations in children and adolescents with FASD. The participants consisted of four different groups: one group with histories of prenatal exposure to alcohol, the FASD group; one IQ matched contrast group mostly consisting of children with specific learning disorder (SLD); and two typically-developing control groups (CON1 and CON2). Participants were identified through medical records, random sampling from the Finnish national population registry and email alerts to students. Importantly, the participants in the present studies comprise a group of very carefully clinically characterized children with FASD as the studies were performed in close collaboration with leading experts in the field (Prof. Edward Riley and Prof. Sarah Mattson, Center for Behavioral Teratology, San Diego State University, U.S.A; Prof. Eugene Hoyme, Sanford School of Medicine, University of South Dakota, U.S.A.). In the present thesis, the revised Institute of Medicine diagnostic criteria for FASD were tested on a Finnish population and found to be a reliable tool for differentiating among the subgroups of FASD. A weighted dysmorphology scoring system proved to be a valuable additional adjunct in quantification of growth deficits and dysmorphic features in children with FASD (Study 1). The purpose of Study 2 was to clarify the relationship between alcohol-related dysmorphic features and general cognitive capacity. Results showed a significant correlation between dysmorphic features and cognitive capacity, suggesting that children with more severe growth deficiency and dysmorphic features have more cognitive limitations. This association was, however, only moderate, indicating that physical markers and cognitive capacity not always go hand in hand in individuals with FASD. Behavioral problems in the FASD group proved substantial compared to the typically developing control group. In Study 3 risk and protective factors associated with behavioral problems in the FASD group were explored further focusing on diagnostic and environmental factors. Two groups with elevated risks for behavioral problems emerged: length of time spent in residential care and a low dysmorphology score proved to be the most pervasive risk factor for behavioral problems. The results underscore the clinical importance of appropriate services and care for less visibly alcohol affected children and highlight the need to attend to children with FASD being raised in institutions. With their background of early biological and psychological impairment compounded with less opportunity for a close and continuous caregiver relationship, such children seem to run an especially great risk of adverse life outcomes. Study 4 focused on adaptive abilities such as communication, daily living skills and social skills, in other words skills that are important for gradually enabling an independent life, maintain social relationships and allow the individual to become integrated into society. The results showed that adaptive abilities of children and adolescents growing up with FASD were significantly compromised compared to both typically-developing peers and IQ-matched children with SLD. Clearly different adaptive profiles were revealed where the FASD group performed worse than the SLD group, who in turn performed worse than the CON1 group. Importantly, the SLD group outperformed the FASD group on adaptive behavior in spite of comparable cognitive levels. This is the first study to compare adaptive abilities in a group of children and adolescents with FASD relative to both a contrast group of IQ-matched children with SLD and to a group of typically-developing peers. Finally, in Study 5, through magnetic resonance spectroscopic imaging (MRS) evidence of longstanding neurochemical alterations were observed in adolescents and young adults with FASD related to alcohol exposure in utero 14-20 years earlier. Neurochemical alterations were seen in several brain areas: in frontal and parietal cortices, corpus callosum, thalamus and frontal white matter areas as well as in the cerebellar dentate nucleus. The findings are compatible with neuropsychological findings in FASD. Glial cells seemed to be more affected than neurons. In conclusion, more societal efforts and resources should be focused on recognizing and diagnosing FASD, and supporting subgroups with elevated risk of poor outcome. Without adequate intervention children and adolescents with FASD run a great risk of marginalization and social maladjustment, costly not only to society but also to the lives of the many young people with FASD.
Resumo:
Työssä tutkittiin Ruukki Oyj:n suorasammutetusta S960QC-teräksestä valmistetun kuormaakantavan levyjen ristiliitoksen pienahitsien lujuutta, muodonmuutoskykyä ja vaurioitumismekanismia laajaan kokeelliseen aineistoon perustuen. Tärkeimpänä muuttujana koematriisissa olivat eri MAG-hitsausprosessit. Perinteisen kuumakaarihitsauksen vertailukohteena oli Kemppi Oy:n uusi adaptiivinen valokaaren pituutta säätävä WiseFusion-hitsaustoiminto kuuma- ja pulssikaarihitsauksessa. Näiden kolmen hitsausprosessin rinnalla varioitiin erisuuruisia a-mittoja, eri hitsauslisäaineita ja hitsin erikylkisyyttä. Lisäksi juuritunkeuman estämisen vaikutusta hitsien käyttäytymiseen tutkittiin täydentävällä koesarjalla, jossa tunkeuman muodostuminen estettiin levyjen väliin asetetulla volframilevyllä. Työn perimmäisenä tavoitteena oli selvittää syy aiemmassa tutkimuksessa havaitulle pienahitsien vaurioitumiselle leikkautumalla sularajaa pitkin. Sularajan suhteellista pituutta saadaan kasvatettua estämällä hitsin juuritunkeuma ja absoluuttista pituutta saadaan lisää kateettipoikkeaman avulla. Lisäksi tutkimuksessa oli tarkoitus tuoda esille suurlujuusteräksisen liitoksen eri mitoituslähtökohdat (mm. lämmöntuonnin kontrollointi). Tämän vuoksi hitsausparametrit mitattiin jännitteen ja virran hetkellisiin arvoihin perustuen, jolloin kuuma- ja pulssikaarihitsauksen laskennalliset hitsaustehot ovat vertailukelpoisia. Koehitseistä valmistettiin hieet hitsien tarkan geometrian määrittämiseksi ja liitoksen mekaaniset ominaisuudet tutkittiin vetokokeella. Tulosten perusteella sularajavaurio aktivoituu pulssikaarella hitsatuissa koekappaleissa. Tämä aiheutunee pulssi- ja kuumakaarihitsauksen sularajan mikrorakenteiden eroavaisuudesta. Sularajavaurio näyttää huonontavan hitsien muodonmuutoskykyä, mutta jatkokokeita tuloksen verifioimiseksi on tehtävä. S960QC-teräkselle ominaisen pehmenneen vyöhykkeen vaurio ei aktivoitunut, vaikka Ruukin antamat jäähtymisaikasuositukset ylitettiin reilusti.
Resumo:
Through advances in technology, System-on-Chip design is moving towards integrating tens to hundreds of intellectual property blocks into a single chip. In such a many-core system, on-chip communication becomes a performance bottleneck for high performance designs. Network-on-Chip (NoC) has emerged as a viable solution for the communication challenges in highly complex chips. The NoC architecture paradigm, based on a modular packet-switched mechanism, can address many of the on-chip communication challenges such as wiring complexity, communication latency, and bandwidth. Furthermore, the combined benefits of 3D IC and NoC schemes provide the possibility of designing a high performance system in a limited chip area. The major advantages of 3D NoCs are the considerable reductions in average latency and power consumption. There are several factors degrading the performance of NoCs. In this thesis, we investigate three main performance-limiting factors: network congestion, faults, and the lack of efficient multicast support. We address these issues by the means of routing algorithms. Congestion of data packets may lead to increased network latency and power consumption. Thus, we propose three different approaches for alleviating such congestion in the network. The first approach is based on measuring the congestion information in different regions of the network, distributing the information over the network, and utilizing this information when making a routing decision. The second approach employs a learning method to dynamically find the less congested routes according to the underlying traffic. The third approach is based on a fuzzy-logic technique to perform better routing decisions when traffic information of different routes is available. Faults affect performance significantly, as then packets should take longer paths in order to be routed around the faults, which in turn increases congestion around the faulty regions. We propose four methods to tolerate faults at the link and switch level by using only the shortest paths as long as such path exists. The unique characteristic among these methods is the toleration of faults while also maintaining the performance of NoCs. To the best of our knowledge, these algorithms are the first approaches to bypassing faults prior to reaching them while avoiding unnecessary misrouting of packets. Current implementations of multicast communication result in a significant performance loss for unicast traffic. This is due to the fact that the routing rules of multicast packets limit the adaptivity of unicast packets. We present an approach in which both unicast and multicast packets can be efficiently routed within the network. While suggesting a more efficient multicast support, the proposed approach does not affect the performance of unicast routing at all. In addition, in order to reduce the overall path length of multicast packets, we present several partitioning methods along with their analytical models for latency measurement. This approach is discussed in the context of 3D mesh networks.
Resumo:
The capacity of beams is a very important factor in the study of durability of structures and structural members. The capacity of a high-strength steel I-beam made of S960 QC was investigated in this study. The investigation included assessment of the service limits and ultimate limits of the steel beam. The thesis was done according to European standards for steel structures, Eurocode 3. An analytical method was used to determine the throat thickness, deformation, elastic and plastic moment capacities as well as the fatigue life of the beam. The results of the analytical method were compared with those obtained by Finite Element Analysis (FEA). Elastic moment capacity obtained by the analytical method was 172 kNm. FEA and the analytical method predicted the maximum lateral-torsional buckling (LTB) capacity in the range of 90-93 kNm and the probability of failure as a result of LTB is estimated to be 50%. The lateral buckling capacity meant that the I-beam can carry a safe load of 300 kN instead of the initial load of 600 kN. The beam is liable to fail shortly after exceeding the elastic moment capacity. Based on results in of the different approaches, it was noted that FEA predicted higher deformation values on the load-deformation curve than the analytical results. However, both FEA and the analytical methods predicted identical results for nominal stress range and moment capacities. Fatigue life was estimated to be in the range of 53000-64000 cycles for bending stress range using crack propagation equation and strength-life approach. As Eurocode 3 is limited to steel grades up to S690, results for S960 must be verified with experimental data and appropriate design rules.
Resumo:
One of the main goals in current evolutionary biology research is to identify genes behind adaptive phenotypic variations. The advances in genomic technologies have made it possible to identify genetic loci behind these variations, also concerning non-model species. This thesis investigates the genetics of the behaviour and other adaptive traits of the nine-spined stickleback (Pungitius pungitius) through the application of different genetic approaches. Fennoscandian nine-spined stickleback populations express large phenotypical differences especially in behaviour, life –history traits and morphology. However the underlying genetic bases for these phenotypical differences have not been studied in detail. The results of the project will lay the foundation for further genetics studies and provide valuable information for our understanding of the genetics of the adaptive divergence of the nine-spined stickleback. A candidate gene approach was used to develop microsatellite markers situating close to candidate genes for behaviour in the nine-spined stickleback. Altogether 13 markers were developed and these markers were used in the subsequent studies with the anonymous random markers and physiologically important gene markers which are already currently available for nine-spined sticklebacks. It was shown that heterozygosity correlated with behaviour in one of the marine nine-spined stickleback populations but with contrasting effects: correlations with behaviour were negative when using physiological gene markers and positive with random markers. No correlation was found between behavioural markers and behaviour. From the physiological gene markers, a strong correlation was found between osmoregulation-related gene markers and behaviour. These results indicate that both local (physiological) and general (random) effects are important in the shaping of behaviour and that heterozygosity– behaviour correlations are population dependent. In this thesis a second linkage map for nine-spined sticklebacks was constructed. Compared to the earlier nine-spined stickleback linkage map, genomic rearrangements were observed between autosomal (LG7) and sex-determing (LG12) linkage groups. This newly constructed map was used in QTL mapping studies in order to locate genomic regions associated with pelvic structures, behaviour and body size/growth. One major QTL was found for pelvic structures and Pitx1 gene was related to these traits as was predicted from three-spined stickleback studies, but this was in contrast to earlier nine-spined stickleback study. The QTL studies also revealed that behaviour and body size/growth were genetically more complex by having more QTL than pelvic traits. However, in many cases, pelvic structure, body size/growth and behaviour were linked to similar map locations indicating possible pleiotropic effects of genes locating in these QTL regions. Many of the gene related markers resided in the QTL area. In the future, studying these possible candidate genes in depth might reveal the underlying mechanism behind the measured traits.
Resumo:
Growing demand for stainless steel construction materials has increased the popularity of substitutive materials for austenitic stainless steels. The lean duplex grades have taken their place in building of structures exposed to corrosive environments. Since the duplex grades are relatively new materials, the current codes and norms do not fully cover the newest duplex grades. The joints tested in this thesis were designed and studied according to Eurocode 3, even though all the materials are not yet accepted to the standards. The main objective in this thesis was to determine the differences of the used materials in behaviour under loading at low temperatures. Tests in which the deformation and strength properties of the joints were determined were done at the temperature of -46°C, which is the requirement of temperature for structures designed according to Norsok standards. Results show that replacing the austenitic grade with the lean duplex grade is acceptable.
Resumo:
In 1859, Charles Darwin published his theory of evolution by natural selection, the process occurring based on fitness benefits and fitness costs at the individual level. Traditionally, evolution has been investigated by biologists, but it has induced mathematical approaches, too. For example, adaptive dynamics has proven to be a very applicable framework to the purpose. Its core concept is the invasion fitness, the sign of which tells whether a mutant phenotype can invade the prevalent phenotype. In this thesis, four real-world applications on evolutionary questions are provided. Inspiration for the first two studies arose from a cold-adapted species, American pika. First, it is studied how the global climate change may affect the evolution of dispersal and viability of pika metapopulations. Based on the results gained here, it is shown that the evolution of dispersal can result in extinction and indeed, evolution of dispersalshould be incorporated into the viability analysis of species living in fragmented habitats. The second study is focused on the evolution of densitydependent dispersal in metapopulations with small habitat patches. It resulted a very surprising unintuitive evolutionary phenomenon, how a non-monotone density-dependent dispersal may evolve. Cooperation is surprisingly common in many levels of life, despite of its obvious vulnerability to selfish cheating. This motivated two applications. First, it is shown that density-dependent cooperative investment can evolve to have a qualitatively different, monotone or non-monotone, form depending on modelling details. The last study investigates the evolution of investing into two public-goods resources. The results suggest one general path by which labour division can arise via evolutionary branching. In addition to applications, two novel methodological derivations of fitness measures in structured metapopulations are given.
Resumo:
Adaptive control systems are one of the most significant research directions of modern control theory. It is well known that every mechanical appliance’s behavior noticeably depends on environmental changes, functioning-mode parameter changes and changes in technical characteristics of internal functional devices. An adaptive controller involved in control process allows reducing an influence of such changes. In spite of this such type of control methods is applied seldom due to specifics of a controller designing. The work presented in this paper shows the design process of the adaptive controller built by Lyapunov’s function method for the Hydraulic Drive. The calculation needed and the modeling were conducting with MATLAB® software including Simulink® and Symbolic Math Toolbox™ etc. In the work there was applied the Jacobi matrix linearization of the object’s mathematical model and derivation of the suitable reference models based on Newton’s characteristic polynomial. The intelligent adaptive to nonlinearities algorithm for solving Lyapunov’s equation was developed. Developed algorithm works properly but considered plant is not met requirement of functioning with. The results showed confirmation that adaptive systems application significantly increases possibilities in use devices and might be used for correction a system’s behavior dynamics.
Resumo:
This thesis is concerned with the state and parameter estimation in state space models. The estimation of states and parameters is an important task when mathematical modeling is applied to many different application areas such as the global positioning systems, target tracking, navigation, brain imaging, spread of infectious diseases, biological processes, telecommunications, audio signal processing, stochastic optimal control, machine learning, and physical systems. In Bayesian settings, the estimation of states or parameters amounts to computation of the posterior probability density function. Except for a very restricted number of models, it is impossible to compute this density function in a closed form. Hence, we need approximation methods. A state estimation problem involves estimating the states (latent variables) that are not directly observed in the output of the system. In this thesis, we use the Kalman filter, extended Kalman filter, Gauss–Hermite filters, and particle filters to estimate the states based on available measurements. Among these filters, particle filters are numerical methods for approximating the filtering distributions of non-linear non-Gaussian state space models via Monte Carlo. The performance of a particle filter heavily depends on the chosen importance distribution. For instance, inappropriate choice of the importance distribution can lead to the failure of convergence of the particle filter algorithm. In this thesis, we analyze the theoretical Lᵖ particle filter convergence with general importance distributions, where p ≥2 is an integer. A parameter estimation problem is considered with inferring the model parameters from measurements. For high-dimensional complex models, estimation of parameters can be done by Markov chain Monte Carlo (MCMC) methods. In its operation, the MCMC method requires the unnormalized posterior distribution of the parameters and a proposal distribution. In this thesis, we show how the posterior density function of the parameters of a state space model can be computed by filtering based methods, where the states are integrated out. This type of computation is then applied to estimate parameters of stochastic differential equations. Furthermore, we compute the partial derivatives of the log-posterior density function and use the hybrid Monte Carlo and scaled conjugate gradient methods to infer the parameters of stochastic differential equations. The computational efficiency of MCMC methods is highly depend on the chosen proposal distribution. A commonly used proposal distribution is Gaussian. In this kind of proposal, the covariance matrix must be well tuned. To tune it, adaptive MCMC methods can be used. In this thesis, we propose a new way of updating the covariance matrix using the variational Bayesian adaptive Kalman filter algorithm.
Resumo:
Potential impacts of electrical capacity market design on capacity mobility and end use customer pricing are analyzed. Market rules and historical evolution are summarized to provide a background for the analysis. The summarized rules are then examined for impacts on capacity mobility. A summary of the aspects of successful capacity markets is provided. Two United States market regions are chosen for analysis based upon their market history and proximity to each other. The MISO region is chosen due to recent developments in capacity market mechanisms. The PJM region neighbors the MISO region and is similar in size and makeup. The PJM region has had a capacity market mechanism for over a decade and allows for a controlled comparison of the MISO region’s developments. Capacity rules are found to have an impact on the mobility of capacity between regions. Regulatory restrictions and financial penalties for the movement of capacity between regions are found which effectively hinder such mobility. Capacity market evolution timelines are formed from the historical evolution previously summarized and compared to historical pricing to inspect for a correlation. No direct and immediate impact on end use customer pricing was found due to capacity market design. The components of end use customer pricing are briefly examined.
Resumo:
Ecological specialization in resource utilization has various facades ranging from nutritional resources via host use of parasites or phytophagous insects to local adaptation in different habitats. Therefore, the evolution of specialization affects the evolution of most other traits, which makes it one of the core issues in the theory of evolution. Hence, the evolution of specialization has gained enormous amounts of research interest, starting already from Darwin’s Origin of species in 1859. Vast majority of the theoretical studies has, however, focused on the mathematically most simple case with well-mixed populations and equilibrium dynamics. This thesis explores the possibilities to extend the evolutionary analysis of resource usage to spatially heterogeneous metapopulation models and to models with non-equilibrium dynamics. These extensions are enabled by the recent advances in the field of adaptive dynamics, which allows for a mechanistic derivation of the invasion-fitness function based on the ecological dynamics. In the evolutionary analyses, special focus is set to the case with two substitutable renewable resources. In this case, the most striking questions are, whether a generalist species is able to coexist with the two specialist species, and can such trimorphic coexistence be attained through natural selection starting from a monomorphic population. This is shown possible both due to spatial heterogeneity and due to non-equilibrium dynamics. In addition, it is shown that chaotic dynamics may sometimes inflict evolutionary suicide or cyclic evolutionary dynamics. Moreover, the relations between various ecological parameters and evolutionary dynamics are investigated. Especially, the relation between specialization and dispersal propensity turns out to be counter-intuitively non-monotonous. This observation served as inspiration to the analysis of joint evolution of dispersal and specialization, which may provide the most natural explanation to the observed coexistence of specialist and generalist species.