Numerical approaches to new particle formation and growth in the atmosphere

Aerosols impact the planet and our daily lives through various effects, perhaps most notably those related to their climatic and health-related consequences. While there are several primary particle sources, secondary new particle formation from precursor vapors is also known to be a frequent, global phenomenon. Nevertheless, the formation mechanism of new particles, as well as the vapors participating in the process, remain a mystery. This thesis consists of studies on new particle formation specifically from the point of view of numerical modeling. A dependence of formation rate of 3 nm particles on the sulphuric acid concentration to the power of 1-2 has been observed. This suggests nucleation mechanism to be of first or second order with respect to the sulphuric acid concentration, in other words the mechanisms based on activation or kinetic collision of clusters. However, model studies have had difficulties in replicating the small exponents observed in nature. The work done in this thesis indicates that the exponents may be lowered by the participation of a co-condensing (and potentially nucleating) low-volatility organic vapor, or by increasing the assumed size of the critical clusters. On the other hand, the presented new and more accurate method for determining the exponent indicates high diurnal variability. Additionally, these studies included several semi-empirical nucleation rate parameterizations as well as a detailed investigation of the analysis used to determine the apparent particle formation rate. Due to their high proportion of the earth's surface area, oceans could potentially prove to be climatically significant sources of secondary particles. In the lack of marine observation data, new particle formation events in a coastal region were parameterized and studied. Since the formation mechanism is believed to be similar, the new parameterization was applied in a marine scenario. The work showed that marine CCN production is feasible in the presence of additional vapors contributing to particle growth. Finally, a new method to estimate concentrations of condensing organics was developed. The algorithm utilizes a Markov chain Monte Carlo method to determine the required combination of vapor concentrations by comparing a measured particle size distribution with one from an aerosol dynamics process model. The evaluation indicated excellent agreement against model data, and initial results with field data appear sound as well.

Essays on Stock Market Reactions to New Information

A functioning stock market is an essential component of a competitive economy, since it provides a mechanism for allocating the economy’s capital stock. In an ideal situation, the stock market will steer capital in a manner that maximizes the total utility of the economy. As prices of traded stocks depend on and vary with information available to investors, it is apparent that information plays a crucial role in a functioning stock market. However, even though information indisputably matters, several issues regarding how stock markets process and react to new information still remain unanswered. The purpose of this thesis is to explore the link between new information and stock market reactions. The first essay utilizes new methodological tools in order to investigate the average reaction of investors to new financial statement information. The second essay explores the behavior of different types of investors when new financial statement information is disclosed to the market. The third essay looks into the interrelation between investor size, behavior and overconfidence. The fourth essay approaches the puzzle of negative skewness in stock returns from an altogether different angle than previous studies. The first essay presents evidence of the second derivatives of some financial statement signals containing more information than the first derivatives. Further, empirical evidence also indicates that some of the investigated signals proxy risk while others contain information priced with a delay. The second essay documents different categories of investors demonstrating systematical differences in their behavior when new financial statement information arrives to the market. In addition, a theoretical model building on differences in investor overconfidence is put forward in order to explain the observed behavior. The third essay shows that investor size describes investor behavior very well. This finding is predicted by the model proposed in the second essay, and hence strengthens the model. The behavioral differences between investors of different size furthermore have significant economic implications. Finally, the fourth essay finds strong evidence of management news disclosure practices causing negative skewness in stock returns.

From Creative Ideas to New Emerging Ventures: Entrepreneurial Processes among Finnish Design Entrepreneurs

This study focuses on self-employed industrial designers and how they emerge new venture ideas. More specifically, this study strives to determine what design entrepreneurs do when they create new venture ideas, how venture ideas are nurtured into being, and how the processes are organized to bring such ideas to the market in the given industrial context. In contemporary times when the concern for the creative class is peaking, the research and business communities need more insight of the kind that this study provides, namely how professionals may contribute to their entrepreneurial processes and other agents’ business processes. On the one hand, the interviews underlying this study suggest that design entrepreneurs may act as reactive service providers who are appointed by producers or marketing parties to generate product-related ideas on their behalf. On the other hand, the interviews suggest that proactive behaviour that aims on generating own venture ideas, may force design entrepreneurs to take considerable responsibility in organizing their entrepreneurial processes. Another option is that they strive to bring venture ideas to the market in collaboration, or by passing these to other agents’ product development processes. Design entrepreneurs’ venture ideas typically emerge from design related starting points and observations. Product developers are mainly engaged with creating their own ideas, whereas service providers refer mainly to the development of other agents’ venture ideas. In contrast with design entrepreneurs, external actors commonly emphasize customer demand as their primary source for new venture ideas, as well as development of these in close interaction with available means of production and marketing. Consequently, design entrepreneurs need to address market demand since without sales their venture ideas may as well be classified as art. In case, they want to experiment with creative ideas, then there should be another source of income to support this typically uncertain and extensive process. Currently, it appears like a lot of good venture ideas and resources are being wasted, when venture ideas do not suite available production or business procedures. Sufficient communication between design entrepreneurs and other agents would assist all parties in developing production efficient and distributable venture ideas. Overall, the findings suggest that design entrepreneurs are often involved simultaneously in several processes that aim at emerging new product related ventures. Consequently, design entrepreneurship is conceptualized in this study as a dual process. This implies that design entrepreneurs can simultaneously be in charge of their entrepreneurial processes, as they operate as resources in other agents’ business processes. The interconnection between activities and agents suggests that these kinds of processes tend to be both complex and multifaceted to their nature.

How Do Different Types of Investors React to New Financial Statement Information?

The study contributes to our understanding of the forces that drive the stock market by investigating how different types of investors react to new financial statement information. Using the extremely comprehensive official register of share holdings in Finland, we find that the majority of investors are more probable to sell (buy) stocks in a company after a positive (negative) earnings surprise, and show a bias towards buying after the disclosure of new financial statement information. Large investors, on the other hand, show behavior opposite to that of the majority of investors in the market. Further, foreign investors show behavior similar to that of domestic investors. We suggest investor overconfidence and asymmetric information as possible explanations for the documented behavior.

The Media and the Academic Globalization Debate : Theoretical Analysis and Critique

This study offers a reconstruction and critical evaluation of globalization theory, a perspective that has been central for sociology and cultural studies in recent decades, from the viewpoint of media and communications. As the study shows, sociological and cultural globalization theorists rely heavily on arguments concerning media and communications, especially the so-called new information and communication technologies, in the construction of their frameworks. Together with deepening the understanding of globalization theory, the study gives new critical knowledge of the problematic consequences that follow from such strong investment in media and communications in contemporary theory. The book is divided into four parts. The first part presents the research problem, the approach and the theoretical contexts of the study. Followed by the introduction in Chapter 1, I identify the core elements of globalization theory in Chapter 2. At the heart of globalization theory is the claim that recent decades have witnessed massive changes in the spatio-temporal constitution of society, caused by new media and communications in particular, and that these changes necessitate the rethinking of the foundations of social theory as a whole. Chapter 3 introduces three paradigms of media research the political economy of media, cultural studies and medium theory the discussion of which will make it easier to understand the key issues and controversies that emerge in academic globalization theorists treatment of media and communications. The next two parts offer a close reading of four theorists whose works I use as entry points into academic debates on globalization. I argue that we can make sense of mainstream positions on globalization by dividing them into two paradigms: on the one hand, media-technological explanations of globalization and, on the other, cultural globalization theory. As examples of the former, I discuss the works of Manuel Castells (Chapter 4) and Scott Lash (Chapter 5). I maintain that their analyses of globalization processes are overtly media-centric and result in an unhistorical and uncritical understanding of social power in an era of capitalist globalization. A related evaluation of the second paradigm (cultural globalization theory), as exemplified by Arjun Appadurai and John Tomlinson, is presented in Chapter 6. I argue that due to their rejection of the importance of nation states and the notion of cultural imperialism for cultural analysis, and their replacement with a framework of media-generated deterritorializations and flows, these theorists underplay the importance of the neoliberalization of cultures throughout the world. The fourth part (Chapter 7) presents a central research finding of this study, namely that the media-centrism of globalization theory can be understood in the context of the emergence of neoliberalism. I find it problematic that at the same time when capitalist dynamics have been strengthened in social and cultural life, advocates of globalization theory have directed attention to media-technological changes and their sweeping socio-cultural consequences, instead of analyzing the powerful material forces that shape the society and the culture. I further argue that this shift serves not only analytical but also utopian functions, that is, the longing for a better world in times when such longing is otherwise considered impracticable.

Actin Dynamics in Muscle Cells

In every cell, actin is a key component involved in migration, cytokinesis, endocytosis and generation of contraction. In non-muscle cells, actin filaments are very dynamic and regulated by an array of proteins that interact with actin filaments and/or monomeric actin. Interestingly, in non-muscle cells the barbed ends of the filaments are the predominant assembly place, whereas in muscle cells actin dynamics was reported to predominate at the pointed ends of thin filaments. The actin-based thin filament pointed (slow growing) ends extend towards the middle of the sarcomere's M-line where they interact with the thick filaments to generate contraction. The actin filaments in muscle cells are organized into a nearly crystalline array and are believed to be significantly less dynamic than the ones in other cell types. However, the exact mechanisms of the sarcomere assembly and turnover are largely unknown. Interestingly, although sarcomeric actin structures are believed to be relatively non-dynamic, many proteins promoting actin dynamics are expressed also in muscle cells (e.g ADF/cofilin, cyclase-associated protein and twinfilin). Thus, it is possible that the muscle-specific isoforms of these proteins promote actin dynamics differently from their non-muscle counterparts, or that actin filaments in muscle cells are more dynamic than previously thought. To study protein dynamics in live muscle cells, I used primary cell cultures of rat cardiomyocytes. My studies revealed that a subset of actin filaments in cardiomyocyte sarcomeres displays rapid turnover. Importantly, I discovered that the turnover of actin filaments depends on contractility of the cardiomyocytes and that the contractility-induced actin dynamics plays an important role in sarcomere maturation. Together with previous studies those findings suggest that sarcomeres undergo two types of actin dynamics: (1) contractility-dependent turnover of whole filaments and (2) regulatory pointed end monomer exchange to maintain correct thin filament length. Studies involving an actin polymerization inhibitor suggest that the dynamic actin filament pool identified here is composed of filaments that do not contribute to contractility. Additionally, I provided evidence that ADF/cofilins, together with myosin-induced contractility, are required to disassemble non-productive filaments in developing cardiomyocytes. In addition, during these studies we learned that isoforms of actin monomer binding protein twinfilin, Twf-1 and Twf-2a localise to myofibrils in cardiomyocytes and may thus contribute to actin dynamics in myofibrils. Finally, in collaboration with Roberto Dominguez s laboratory we characterized a new actin nucleator in muscle cells - leiomodin (Lmod). Lmod localises towards actin filament pointed ends and its depletion by siRNA leads to severe sarcomere abnormalities in cardiomyocytes. The actin filament nucleation activity of Lmod is enhanced by interactions with tropomyosin. We also revealed that Lmod expression correlates with the maturation of myofibrils, and that it associates with sarcomeres only at relatively late stages of myofibrillogenesis. Thus, Lmod is unlikely to play an important role in myofibril formation, but rather might be involved in the second step of the filament arrangement and/or maintenance through its ability to promote tropomyosin-induced actin filament nucleation occurring at the filament pointed ends. The results of these studies provide valuable new information about the molecular mechanisms underlying muscle sarcomere assembly and turnover. These data offer important clues to understanding certain physiological and pathological behaviours of muscle cells. Better understanding of the processes occurring in muscles might help to find strategies for determining, diagnosis, prognosis and therapy in heart and skeletal muscles diseases.

Dynamics of Finnish starlings in 1951-2005 : from monitoring to population modelling

Farmland bird species have been declining in Europe. Many declines have coincided with general intensification of farming practices. In Finland, replacement of mixed farming, including rotational pastures, with specialized cultivation has been one of the most drastic changes from the 1960s to the 1990s. This kind of habitat deterioration limits the persistence of populations, as has been previously indicated from local populations. Integrated population monitoring, which gathers species-specific information of population size and demography, can be used to assess the response of a population to environment changes also at a large spatial scale. I targeted my analysis at the Finnish starling (Sturnus vulgaris). Starlings are common breeders in farmland habitats, but severe declines of local populations have been reported from Finland in the 1970s and 1980s and later from other parts of Europe. Habitat deterioration (replacement of pasture and grassland habitats with specialized cultivation areas) limits reproductive success of the species. I analysed regional population data in order to exemplify the importance of agricultural change to bird population dynamics. I used nestling ringing and nest-card data from 1951 to 2005 in order to quantify population trends and per capita reproductive success within several geographical regions (south/north and west/east aspects). I used matrix modelling, acknowledging age-specific survival and fecundity parameters and density-dependence, to model population dynamics. Finnish starlings declined by 80% from the end of the 1960s up to the end of the 1980s. The observed patterns and the model indicated that the population decline was due to the decline of the carrying capacity of farmland habitats. The decline was most severe in north Finland where populations largely become extinct. However, habitat deterioration was most severe in the southern breeding areas. The deteriorations in habitat quality decreased reproduction, which finally caused the decline. I suggest that poorly-productive northern populations have been partly maintained by immigration from the highly-productive southern populations. As the southern populations declined, ceasing emigration caused the population extinction in north. This phenomenon was explained with source sink population dynamics, which I structured and verified on the basis of a spatially explicit simulation model. I found that southern Finnish starling population exhibits ten-year cyclic regularity, a phenomenon that can be explained with delayed density-dependence in reproduction.

Experiments on homogeneous nucleation and physicochemical properties related to atmospheric new particle formation

Aerosol particles play a role in the earth ecosystem and affect human health. A significant pathway of producing aerosol particles in the atmosphere is new particle formation, where condensable vapours nucleate and these newly formed clusters grow by condensation and coagulation. However, this phenomenon is still not fully understood. This thesis brings an insight to new particle formation from an experimental point of view. Laboratory experiments were conducted both on the nucleation process and physicochemical properties related to new particle formation. Nucleation rate measurements are used to test nucleation theories. These theories, in turn, are used to predict nucleation rates in atmospheric conditions. However, the nucleation rate measurements have proven quite difficult to conduct, as different devices can yield nucleation rates with differences of several orders of magnitude for the same substances. In this thesis, work has been done to have a greater understanding in nucleation measurements, especially those conducted in a laminar flow diffusion chamber. Systematic studies of nucleation were also made for future verification of nucleation theories. Surface tensions and densities of substances related to atmospheric new particle formation were measured. Ternary sulphuric acid + ammonia + water is a proposed candidate to participate in atmospheric nucleation. Surface tensions of an alternative candidate to nucleate in boreal forest areas, sulphuric acid + dimethylamine + water, were also measured. Binary compounds, consisting of organic acids + water are possible candidates to participate in the early growth of freshly nucleated particles. All the measured surface tensions and densities were fitted with equations, thermodynamically consistent if possible, to be easily applied to atmospheric model calculations of nucleation and subsequent evolution of particle size.

A Recursive Perspective on Discursive Legitimation and Organizational Action in Mergers and Acquisitions

This paper challenges the predominant view that legitimation is merely a specific phase in merger or acquisition processes. We argue that a better understanding of postmerger organizational dynamics calls for conceptualization of discursive legitimation as an inherent part of unfolding merger processes. In particular, we focus on the recursive relationship between legitimation and organizational action. We have two objectives: to outline a theoretical model that helps one to understand the dynamics of discursive legitimation and organizational action in postmerger organizations, and to examine a revealing case to distinguish the inherent risks and problems in discursive legitimation. Our case analysis focuses on the merger between the French pharmaceutical companies BioMérieux and Pierre Fabre. We adopt a critical multimethod approach and distinguish specific discursive dynamics and pathological tendencies in this case. The analysis highlights the unintended consequences of discursive legitimation, the central role of sensegiving and sensehiding in discursive legitimation, the inherently political nature of legitimation and the risks associated with politicization, the special problems associated with fashionable discourses and the role of the media, the use of specific discursive strategies for legitimation and delegitimation, and the crucial role of actual integration results. This analysis adds to the existing research on mergers and acquisitions by treating discursive legitimation as part of the merger dynamics. In particular, our case analysis provides a new explanation for merger failure. We also believe that the recursive model connecting discursive legitimation and delegitimation strategies to concrete organizational action makes a more general contribution to our understanding of organizational legitimation.

A recursive perspective on discursive legitimation and organizational action in mergers and acquisitions

This paper challenges the predominant view that legitimation is merely a specific phase in merger or acquisition processes. We argue that a better understanding of postmerger organizational dynamics calls for conceptualization of discursive legitimation as an inherent part of unfolding merger processes. In particular, we focus on the recursive relationship between legitimation and organizational action. We have two objectives: to outline a theoretical model that helps one to understand the dynamics of discursive legitimation and organizational action in postmerger organizations, and to examine a revealing case to distinguish the inherent risks and problems in discursive legitimation. Our case analysis focuses on the merger between the French pharmaceutical companies BioMérieux and Pierre Fabre. We adopt a critical multimethod approach and distinguish specific discursive dynamics and pathological tendencies in this case. The analysis highlights the unintended consequences of discursive legitimation, the central role of sensegiving and sensehiding in discursive legitimation, the inherently political nature of legitimation and the risks associated with politicization, the special problems associated with fashionable discourses and the role of the media, the use of specific discursive strategies for legitimation and delegitimation, and the crucial role of actual integration results. This analysis adds to the existing research on mergers and acquisitions by treating discursive legitimation as part of the merger dynamics. In particular, our case analysis provides a new explanation for merger failure. We also believe that the recursive model connecting discursive legitimation and delegitimation strategies to concrete organizational action makes a more general contribution to our understanding of organizational legitimation.

Essays on Platforms: Business Strategies, Regulation and Policy in Telecommunications, Media and Technology Industries

The growth of the information economy has been stellar in the last decade. General-purpose technologies such as the computer and the Internet have promoted productivity growth in a large number of industries. The effect on telecommunications, media and technology industries has been particularly strong. These industries include mobile telecommunications, printing and publishing, broadcasting, software, hardware and Internet services. There have been large structural changes, which have led to new questions on business strategies, regulation and policy. This thesis focuses on four such questions and answers them by extending the theoretical literature on platforms. The questions (with short answers) are: (i) Do we need to regulate how Internet service providers discriminate between content providers? (Yes.) (ii) What are the welfare effects of allowing consumers to pay to remove advertisements from advertisement-supported products?(Ambiguous, but those watching ads are worse off.) (iii) Why are some markets characterized by open platforms, extendable by third parties, and some by closed platforms, which are not extendable? (It is a trade-off between intensified competition for consumers and benefits from third parties) (iv) Do private platform providers allow third parties to access their platform when it is socially desirable? (No.)