The purpose of this investigation was to find out more about students’ spontaneous ideas about properties and transformations of matter. Examples of matter chosen are such which students know about from everyday life and focus is mainly on the questions if students know that all matter has weight and that matter is preserved in transformations. The method used is semi structured qualitative interviews with individual students. Different experiments were carried out together with the students who afterwards were interviewed. However, the students show varying answers and no generalizations can be done. However, when their conclusions from observations differ from their earlier experiences they trust their eyes. All students know that a human body has weight as well as a grain of dust. They also know that with addition of a colored substance in the water, the mass increases, but more hesitation exists when the additive is sugar. A couple of students are capable of discussing logically sometimes but not at all events. / Undersökningens syfte var att undersöka vad elever i årskurs tre har för spontana uppfattningar om materiens egenskaper och dess transformationer. Exempel på materia som valts är det eleverna känner till i vardagen och undersökningen har främst fokuserat på om eleverna dels vet att all materia väger något samt dels att materia är beständig och inte försvinner vid transformationer. Metoden som använts är semistrukturerade kvalitativa intervjuer med enskilda elever. Olika försök genomfördes tillsammans med eleverna som sedan intervjuades. Resultatet visar att eleverna varierar sina svar. Inga generella slutsatser kan dras. Dock kan man se att de grundar sina svar på det de ser och knyter sina föreställningar till sin vardag. När ögats uppfattning inte överensstämmer med erfarenheter litar flertalet elever på ögats observation. Alla elever vet att en människa väger liksom dammkorn. De vet också att vid tillsats av en färgad substans i vatten så ökar massan men fler oklarheter råder vid tillsats av socker. Ett par elever förmår resonera logiskt vid ett tillfälle men inte vid ett annat.

In recent years, advances in signal processing have led to small, low power, inexpensive Wireless Sensor Network (WSN). The signal processing in WSN is different from the traditional wireless networks in two critical aspects: firstly, the signal processing in WSN is performed in a fully distributed manner, unlike in traditional wireless networks; secondly, due to the limited computation capabilities of sensor networks, it is essential to develop an energy and bandwidth efficient signal processing algorithms. Target localisation and tracking problems in WSNs have received considerable attention recently, driven by the necessity to achieve higher localisation accuracy, lower cost, and the smallest form factor. Received Signal Strength (RSS) based localisation techniques are at the forefront of tracking research applications. Since tracking algorithms have been attracting research and development attention recently, prolific literature and a wide range of proposed approaches regarding the topic have emerged. This thesis is devoted to discussing the existing WSN-based localisation and tracking approaches. This thesis includes five studies. The first study leads to the design and implementation of a triangulation-based localisation approach using RSS technique for indoor tracking applications. The presented work achieves low localisation error in complex environments by predicting the environmental characteristics among beacon nodes. The second study concentrates on investigating a fingerprinting localisation method for indoor tracking applications. The proposed approach offers reasonable localisation accuracy while requiring a short period of offline computation time. The third study focuses on designing and implementing a decentralised tracking approach for tracking multiple mobile targets with low resource requirements. Despite the interest in target tracking and localisation issues, there are few systems deployed using ZigBee network standard, and no tracking system has used the full features of the ZigBee network standard. Tracking through the ZigBee is a challenging task when the density of router and end-device nodes is low, due to the limited communication capabilities of end-device nodes. The fourth study focuses on developing and designing a practical ZigBee-based tracking approach. To save energy, different strategies were adopted. The fifth study outlines designing and implementing an energy-efficient approach for tracking applications. This study consists of two main approaches: a data aggregation approach, proposed and implemented in order to reduce the total number of messages transmitted over the network; and a prediction approach, deployed to increase the lifetime of the WSN. For evaluation purposes, two environmental models were used in this thesis: firstly, real experiments, in which the proposed approaches were implemented on real sensor nodes, to test the validity for the proposed approaches; secondly, simulation experiments, in which NS-2 was used to evaluate the power-consumption issues of the two approaches proposed in this thesis.

This study examines, from a modelling point of view, the dynamics of infectious diseases in wildlife caused by macroparasites and by tick-borne infections. The overall aim was to investigate the important role played by parasite aggregation in the dynamics of both systems. For macroparasites we first developed some deterministic models that incorporate explicit mechanisms for generating aggregation in parasite distribution, specifically multiple infections and host heterogeneity. We explored the role of aggregation in host regulation and in determining a threshold value for parasite establishment. A large aggregation makes it more difficult for parasites both to regulate hosts, and to get established in a population at carrying capacity. Furthermore, the stabilization yielded by aggregation strongly depends on the mechanism that produces the aggregation. We then introduced some uncertainties into the host-macroparasite system, presenting an individual-based stochastic model that incorporated the same assumptions as the deterministic model. Stochastic simulations, using parameter values based on some real case studies, preserved many features of the deterministic model, like the average value of the variables and the approximate length of the cycles. An important difference is that, even when deterministic models yield damped oscillations, stochastic simulations yield apparently sustained oscillations. The amplitude of such oscillations may be so large as to threaten the parasites’ persistence. With respect to tick-borne diseases we presented a general model framework that incorporated both viraemic and non-viraemic routes of infections. We compute the threshold for disease persistence and study its dependence on the parameters and on host densities. The effects of tick aggregation and correlation between different tick stages on the host have both an important effect on infection persistence, if non-viraemic transmission occurred. In the case of Lyme Disease and Tick-borne Encephalitis (TBE) in Trentino (northern Italy) we showed some numerical results, using parameter estimates based on a detailed field study, and explored the effects of uncertainty on the endemic equilibrium of both diseases assuming only viraemic transmission for Lyme Disease while for TBE we permitted only non-viraemic transmission through co-feeding ticks. In conclusion we have examined the patterns and changes of aggregation in a number of contrasting systems and believe that these studies highlight both the importance of considering heterogeneities in modelling host-parasite interactions and, more specifically, modelling the biological mechanisms that produce aggregation in parasite distributions.

In state-of-the-art fiber-optics communication systems the fixed forward error correction (FEC) and constellation size are employed. While it is important to closely approach the Shannon limit by using turbo product codes (TPC) and low-density parity-check (LDPC) codes with soft-decision decoding (SDD) algorithm; rate-adaptive techniques, which enable increased information rates over short links and reliable transmission over long links, are likely to become more important with ever-increasing network traffic demands. In this invited paper, we describe a rate adaptive non-binary LDPC coding technique, and demonstrate its flexibility and good performance exhibiting no error floor at BER down to 10(-15) in entire code rate range, by FPGA-based emulation, making it a viable solution in the next-generation high-speed intelligent aggregation networks.

Although gold nanoparticles (GNPs) are promising probes for biological imaging because of their attracting optical properties and bio-friendly nature, properties of the multi-photon (MP) emission from GNP aggregates produced by a short-wave infrared (SWIR) laser have not been examined. In this paper, characterization of MP emission from aggregated 50 nm GNPs excited by a femtosecond (fs) laser at 1560 nm is discussed with respect to aggregate structures. The key technique in this work is single particle spectroscopy. A pattern matching technique is applied to correlate MP emission and SEM images, which includes an optimization processes to maximize cross correlation coefficients between a binary microscope image and a binary SEM image with respect to xy displacement, image rotation angle, and image magnification. Once optimization is completed, emission spots are matched to the SEM image, which clarifies GNP ordering and emission properties of each aggregate. Correlation results showed that GNP aggregates have stronger MP emission than single GNPs. By combining the pattern matching technique with spectroscopy, MP emission spectrum is characterized for each GNP aggregate. A broad spectrum in the visible region and near infrared (NIR) region is obtained from GNP dimers, unlike previously reported surface plasmon enhanced emission spectrum.

This thesis comprises four chapters, in two parts. The first part examines the result of a Swedish payroll tax reduction; first from the perspective of the worker, then from that of the employer. The second half of the thesis concerns subjective well-being, both from an individual and from an aggregate viewpoint. Payroll Taxes and Youth Labor Demand. In 2007, the Swedish payroll tax was reduced substantially for young workers. This paper examines whether targeted payroll tax reductions are effective in raising youth employment. We estimate a small impact, both on employment and on wages. However, the effect differs markedly across ages, with 4–5 times higher impact on 22–23 year-olds compared to 25-year-olds. Additionally, the employment effects are strongly procyclical, approaching zero in the deep recession. We calculate that the estimated cost per created job is more than four times that of directly hiring workers at the average wage. Payroll Taxes and Firm Performance. The Swedish payroll tax reform of 2007 had the effect that firms' average social fees came to depend on the age structure of their employees. This makes it possible to estimate how firms respond to shocks in labor costs. We find a significant, but very small effect on gross investments, and a negative, but not statistically significant, impact on labor productivity. There are no effects on exit rates or profitability. Beyond Income: The Importance for Life Satisfaction of Having Access to a Cash Margin. We study how life satisfaction among adult Swedes is influenced by having access to a cash margin, i.e. a moderate amount of money that could be acquired on short notice either through own savings, by loan from family or friends, or by other means. We find that cash margin is a strong and robust predictor of life satisfaction, also when controlling for individual fixed-effects and socio-economic conditions, including income. This suggests that cash margin captures something beyond wealth. On Aggregating Subjective Well-Being. This paper discusses the assumptions underlying the aggregation of individually measured well-being. Any aggregation method is associated with measurability assumptions regarding the underlying well-being measure, as well as moral philosophical assumptions with respect to how individual well-being is weighted into a composite metric. I compare welfare across a set of countries, under alternative aggregation methods, and find that countries often can be ranked under comparatively weak measurement assumptions, and, equally important, that aggregation methods can be chosen so as to refrain from strong ethical preconceptions.

We review the current state on the thermodynamic behavior and structural phases of self- and mutually-attractive dilute semiflexible polymers that undergo temperature-driven transitions. In extreme dilution, polymers may be considered isolated, and this single polymer undergoes a collapse or folding transition depending on the internal structure. This may go as far as to stable knot phases. Adding polymers results in aggregation, where structural motifs again depend on the internal structure. We discuss in detail the effect of semiflexibility on the collapse and aggregation transition and provide perspectives for interesting future investigations.

This thesis aims to articulate and defend a version of a 'relational moral theory.' Many philosophers have argued that the non-instrumental value of certain relationships, such as friendship and parenthood, can explain at least some of our moral obligations. A relational moral theory extends this thought by arguing that all, or most, of our moral judgements can be explained by the non-instrumental value of one or more interpersonal relationships. The plausibility of such views depend on the possibility of identifying a relationship that all moral agents share a 'moral relationship'. While the idea of such a relationship has featured in ethical writings as early as the Stoics, few attempts have been made to develop a rigorous and precise understanding of this relationship. This thesis therefore aims to articulate and defend a plausible understanding of the moral relationship, and then to use it as a basis for outlining the structure of a genuinely relational moral theory. It will argue that the moral relationship is best understood as a broad and inclusive relationship shared by all who are vulnerable to a distinct kind of 'second-order evil.' It will then argue that the value of this relationship can provide the basis for a relational form of a contractualist moral theory based on the work of T.M. Scanlon. Understanding the nature of the moral relationship, and the role it plays in such theories, will then be seen as a means of unifying, clarifying, and responding to a number of influential objections against such theories, including objections concerning its capacity to accommodate intuitions concerning cases of aggregation and our obligations to future persons.

Satellite imagery and remote sensing provide explanatory variables at relatively high resolutions for modeling geospatial phenomena, yet regional summaries are often desirable for analysis and actionable insight. In this paper, we propose a novel method of inducing spatial aggregations as a component of the statistical learning process, yielding regional model features whose construction is driven by model prediction performance rather than prior assumptions. Our results demonstrate that Genetic Programming is particularly well suited to this type of feature construction because it can automatically synthesize appropriate aggregations, as well as better incorporate them into predictive models compared to other regression methods we tested. In our experiments we consider a specific problem instance and real-world dataset relevant to predicting snow properties in high-mountain Asia.

Carbon nanotubes (CNTs) are of special interest to industry and they have been increasingly utilised as advanced nanovectors in drug/gene delivery systems. They possess significant advantages including high surface area, welldefined morphologies, unique optical property, superior mechanical strength and thermal conductivity. However, despite their unique and advanced physicochemical properties, the low compatibility of some of those materials [e.g. multiwalled CNTs (MWCNTs)] in most biological and chemical environments has also generated some serious health and environment concerns. Chemical functionalization broadens CNT applications, conferring new functions, and at the same time was found potentially altering toxicity. Although considerable experimental data related to functionalised CNT toxicity, at the molecular and cellular levels, have been reported, there is very limited information available for the corresponding mechanism involved (e.g. cell apoptosis, genotoxicity. The toxicity of carbon nanotubes has been confirmed on many cell lines including A549 (lung cancer cell line) and MRC-5 (lung fibroblasts). However, the sensitivity of each cell line in terms of cellular morphology, apoptosis and DNA damage are still unknown. In this report the different levels of cellular response to oxidative stress and phagocytosis have been investigated in A549, MCF-7 and MRC-5 cell lines to better understand the mechanisms of the toxicity pathway. siRNA as an ideal personalized therapeutics can specifically regulate gene expression, but efficient delivery of siRNA is difficult while it has been shown that MWCNTs protect siRNA, facilitate entry into cells. In this study, we comprehensively evaluated the in vitro cytotoxicity of pristine and functionalized (-OH, -COOH) multi-wall carbon nanotubes (MWCNTs), via cell viability test, reactive oxygen species (ROS) generation test, cell apoptosis and DNA mutation detection, to investigate the non-toxic dose and influence of functional group in A549, MCF-7 and MRC-5 cells exposed to 1-1000 μg/mL MWCNTs from 6 to 72 hours. In addition, 84 toxicity related genes have been detected to investigate the change of RNA regulation after treatment with MWCNTs. The research findings suggest that functionalized MWCNTs are more genotoxic compared to their pristine form, and the level of both dose and dispersion in the matrix used should be taken into consideration before applying further clinical applications of MWCNTs. Among all three cell lines, MCF-7 was the most sensitive to cell death and DNA damage induced by pristine carbon nanotubes. The majority of MCF-7 cell death was in necrotic. In A549 cells, apoptosis played a notable role in cytotoxicity. MRC-5 didn’t show significant cell loss or membrane damage, which might be explained by its low cell growth rate, notably however, a great reduction of the F-actin and attachment points was observed after treatment which indicates that MRC-5 cells are under very unhealthy condition and less attached to the bottom of flasks. Despite their toxicity, which is still being researched, carbon nanotubes have a great potential in clinical medicine. Thus, understanding the sensitivity of different cell lines could offer a more individualized approach for future treatment regimes. In regards to gene delivery, MWCNTs were found to be less toxic than chemical agents (positive control) without weakening the delivery efficiency, which proves that MWCNTs have a good potential in medicine area.