Lightcurve inversion for asteroid spins and shapes

Knowledge of the physical properties of asteroids is crucial in many branches of solar-system research. Knowledge of the spin states and shapes is needed, e.g., for accurate orbit determination and to study the history and evolution of the asteroids. In my thesis, I present new methods for using photometric lightcurves of asteroids in the determination of their spin states and shapes. The convex inversion method makes use of a general polyhedron shape model and provides us at best with an unambiguous spin solution and a convex shape solution that reproduces the main features of the original shape. Deriving information about the non-convex shape features is, in principle, also possible, but usually requires a priori information about the object. Alternatively, a distribution of non-convex solutions, describing the scale of the non-convexities, is also possible to be obtained. Due to insufficient number of absolute observations and inaccurately defined asteroid phase curves, the $c/b$-ratio, i.e., the flatness of the shape model is often somewhat ill-defined. However, especially in the case of elongated objects, the flatness seems to be quite well constrained, even in the case when only relative lightcurves are available. The results prove that it is, contrary to the earlier misbelief, possible to derive shape information from the lightcurve data if a sufficiently wide range of observing geometries is covered by the observations. Along with the more accurate shape models, also the rotational states, i.e., spin vectors and rotation periods, are defined with improved accuracy. The shape solutions obtained so far reveal a population of irregular objects whose most descriptive shape characteristics, however, can be expressed with only a few parameters. Preliminary statistical analyses for the shapes suggests that there are correlations between shape and other physical properties, such as the size, rotation period and taxonomic type of the asteroids. More shape data of, especially, the smallest and largest asteroids, as well as the fast and slow rotators is called for in order to be able to study the statistics more thoroughly.

Multiwavelength studies of regolith effects in planetary remote sensing

A large proportion of our knowledge about the surfaces of atmosphereless solar-system bodies is obtained through remote-sensing measurements. The measurements can be carried out either as ground-based telescopic observations or space-based observations from orbiting spacecraft. In both cases, the measurement geometry normally varies during the observations due to the orbital motion of the target body, the spacecraft, etc.. As a result, the data are acquired over a variety of viewing and illumination angles. Surfaces of planetary bodies are usually covered with a layer of loose, broken-up rock material called the regolith whose physical properties affect the directional dependence of remote-sensed measurements. It is of utmost importance for correct interpretation of the remote-sensed data to understand the processes behind this alteration. In the thesis, the multi-angular effects that the physical properties of the regolith have on remote-sensing measurements are studied in two regimes of electromagnetic radiation, visible to near infrared and soft X-rays. These effects are here termed generally the regolith effects in remote sensing. Although the physical mechanisms that are important in these regions are largely different, notable similarities arise in the methodology that is used in the study of the regolith effects, including the characterization of the regolith both in experimental studies and in numerical simulations. Several novel experimental setups have been constructed for the thesis. Alongside the experimental work, theoretical modelling has been carried out, and results from both approaches are presented. Modelling of the directional behaviour of light scattered from a regolith is utilized to obtain shape and spin-state information of several asteroids from telescopic observations and to assess the surface roughness and single-scattering properties of lunar maria from spacecraft observations. One of the main conclusions is that the azimuthal direction is an important factor in detailed studies of planetary surfaces. In addition, even a single parameter, such as porosity, can alter the light scattering properties of a regolith significantly. Surface roughness of the regolith is found to alter the elemental fluorescence line ratios of a surface obtained through planetary soft X-ray spectrometry. The results presented in the thesis are among the first to report this phenomenon. Regolith effects need to be taken into account in the analysis of remote-sensed data, providing opportunities for retrieving physical parameters of the surface through inverse methods.

Diagnostic Tests Based on Quantile Residuals for Nonlinear Time Series Models

This thesis studies quantile residuals and uses different methodologies to develop test statistics that are applicable in evaluating linear and nonlinear time series models based on continuous distributions. Models based on mixtures of distributions are of special interest because it turns out that for those models traditional residuals, often referred to as Pearson's residuals, are not appropriate. As such models have become more and more popular in practice, especially with financial time series data there is a need for reliable diagnostic tools that can be used to evaluate them. The aim of the thesis is to show how such diagnostic tools can be obtained and used in model evaluation. The quantile residuals considered here are defined in such a way that, when the model is correctly specified and its parameters are consistently estimated, they are approximately independent with standard normal distribution. All the tests derived in the thesis are pure significance type tests and are theoretically sound in that they properly take the uncertainty caused by parameter estimation into account. -- In Chapter 2 a general framework based on the likelihood function and smooth functions of univariate quantile residuals is derived that can be used to obtain misspecification tests for various purposes. Three easy-to-use tests aimed at detecting non-normality, autocorrelation, and conditional heteroscedasticity in quantile residuals are formulated. It also turns out that these tests can be interpreted as Lagrange Multiplier or score tests so that they are asymptotically optimal against local alternatives. Chapter 3 extends the concept of quantile residuals to multivariate models. The framework of Chapter 2 is generalized and tests aimed at detecting non-normality, serial correlation, and conditional heteroscedasticity in multivariate quantile residuals are derived based on it. Score test interpretations are obtained for the serial correlation and conditional heteroscedasticity tests and in a rather restricted special case for the normality test. In Chapter 4 the tests are constructed using the empirical distribution function of quantile residuals. So-called Khmaladze s martingale transformation is applied in order to eliminate the uncertainty caused by parameter estimation. Various test statistics are considered so that critical bounds for histogram type plots as well as Quantile-Quantile and Probability-Probability type plots of quantile residuals are obtained. Chapters 2, 3, and 4 contain simulations and empirical examples which illustrate the finite sample size and power properties of the derived tests and also how the tests and related graphical tools based on residuals are applied in practice.

Uuden median murros Alma Mediassa, Sanoma Oy:ssä ja Yleisradiossa 1994-2004

This is a qualitative and multimethodological comparative study, which consists of two main parts: examining the development of new media and analysing and comparing the new media strategies of the three companies studied (Alma Media, Sanoma and the Finnish Broadcasting Company Yleisradio). The study includes the first large-scale review in Finnish of the development of new media, paying attention to the birth of the Internet as well as to mobile media, web TV and any other element of new media. It also concentrates on the function of electronic distribution channels before the age of the Internet, e.g. cable text and videotext. Answers about how the three traditional Finnish media houses began spreading their content to the Internet and wireless applications in 1994–2004 are also given. In researching the new media strategies the study pays special attention to the attitudes that the three media companies adopted towards the Internet and other forms of new media in their strategies during the years in question. By analysing and comparing, e.g., the companies’ strategies and their investments, the study ascertains whether the companies had a joint functional model in adopting new media or acted totally on their own without taking too much notice of the media field overall. The study makes extensive use of previously published material. The researcher has also interviewed almost twenty people who were involved in getting the companies’ new media functions under way. The methods for the interviews were dialogue and snowball sampling. The researcher has created a classification in which he divides the business strategies into four different categories: active strategy, careful strategy, permissive strategy, and passive strategy. In comparing and analysing the companies the researcher has used the classification devised by Allan Afuah & Christopher L. Tucci. The seven element classification consists of dominant managerial logic, competency trap, fear of cannibalisation and loss of revenue, channel conflict, political power, co-opetitor power and emotional attachment. In analysing the company strategies the researcher has also noted the classifications of convergence made by Everette E. Dennis and Graham Murdock as well as the aspects formulated by Sylvia Chan-Olmsted and Louisa Ha concerning the success of the companies in adopting the Internet into their functions. Based on all these classifications and by further developing them the researcher analyses and compares the success of the new media strategies of the three Finnish companies. The outcome of the study is a conclusion as to what kind of strategies the companies have carried out their new media functions and how they have succeeded in it.

Sukupolvien ongelma : Tutkielmia sukupolven käsitteestä, sukupolvitietoisuudesta ja suurista ikäluokista

The aims of the thesis are (1) to present a systematic evaluation of generation and its relevance as a sociological concept, (2) to reflect on how generational consciousness, i.e. generation as an object of collective identification that has social significance, can emerge and take shape, (3) to analyze empirically the generational experiences and consciousness of one specific generation, namely Finnish baby boomers (b. 1945 1950). The thesis contributes to the discussion on the social (as distinct from its genealogical) meaning of the concept of generation, launched by Karl Mannheim s classic Das Problem der Generationen (1928), in which the central idea is that a certain group of people is bonded together by a shared experience and that this bonding can result in a distinct self-consciousness. The thesis is comprised of six original articles and an extensive summarizing chapter. In the empirical articles, the baby boomers are studied on the basis of nationally representative survey data (N = 2628) and narrative life-story interviews (N = 38). In the article that discusses the connection of generations and social movements, the analysis is based on the member survey of Attac Finland (N = 1096). Three main themes were clarified in the thesis. (1) In the social sense the concept of generation is a modern, problematic, and ultimately a political concept. It served the interests of the intellectuals who developed the concept in the early 20th century and provided them, as an alternative to the concept of social class, a new way of think about social change and progress. The concept of generation is always coupled with the concept of Zeitgeist or some other controversial way of defining what is essential, i.e. what creates generations, in a given culture. Thus generation is, as a product of definition and classification struggles, a contested concept. The concept also clearly implies elitist connotations; the idea of some kind of vanguard (the elite) that represents an entire generation by proclaiming itself as its spokesman automatically creates a counterpart, namely the others in the peer group who are thought to be represented (the masses). (2) Generational consciousness cannot emerge as a result of any kind of automatic process or endogenously; it must be made. There has to be somebody who represents the generation in order for that generation to exist in people s minds and as an object of identification; generational experiences and their meanings must be articulated. Hence, social generations are, in a fundamental manner, discursively constructed. The articulations of generational experiences (speeches, writings, manifests, labels etc.) can be called as the discursive dimension of social generations, and through this notion, how public discourse shapes people s generational consciousness can be seen. Another important element in the process is collective memory, as generational consciousness often takes form only retrospectively. (3) Finnish baby boomers are not a united or homogeneous generation but are divided into many smaller sections with specific generational experiences and consciousnesses. The content of the generational consciousness of the baby boomers is heavily politically charged. A salient dividing line inside the age group is formed by individual attitudes towards so-called 1960s radicalism. Identification with the 1960s generation functions today as a positive self-definition of a certain small leftist elite group, and the values and characteristics usually connected with the idea of the 1960s generation do not represent the whole age group. On the contrary, among some of the members of the baby boomers, the generational identification is still directed by the experience of how traditional values were disgraced in the 1960s. As objects of identification, the neutral term baby boomers and the charged 1960s generation are totally different things, and therefore they should not be used as synonyms. Although the significance of the group of the 1960s generation is often overestimated, they are however special with respect to generational consciousness because they have presented themselves as the voice of the entire generation. Their generational interpretations have spread through the media with the help of certain iconic images of the generation insomuch that 1960s radicalism has become an indirect generational experience for other parts of the baby boom cohort as well.

Eron aika : Tyttärien kertomuksia ikääntyneen vanhemman kuolemasta

There is a relative absence of sociological and cultural research on how people deal with the death of a family member in the contemporary western societies. Research on this topic has been dominated by the experts of psychology, psychiatry and therapy, who mention the social context only in passing, if at all. This gives an impression that the white westerners bereavement experience is a purely psychological phenomenon, an inner journey, which follows a natural, universal path. Yet, as Tony Walter (1999) states, ignoring the influence of culture not only impoverishes the understanding of those work with bereaved people, but it also impoverishes sociology and cultural studies by excluding from their domain a key social phenomenon. This study explores the cultural dimension of grief through narratives told by fifteen of recently bereaved Finnish women. Focussing on one sex only, the study rests on the assumption of the gendered nature of bereavement experience. However, the aim of the study is not to pinpoint the gender differences in grief and mourning, but to shed light on women s ways of dealing with the loss of a loved one in a social context. Furthermore, the study focuses on a certain kind of loss: the death of an elderly parent. Due to the growth in the life expectancy rate, this has presumably become the most typical type of bereavement in contemporary, ageing societies. Most of population will face the death of a parent as they reach the middle years of the life course. The data of this study is gathered with interviews, in which the interviewees were invited to tell a narrative of their bereavement. Narrative constitutes a central concept in this study. It refers to a particular form of talk, which is organised around consequential events. But there are also other, deeper layers that have been added to this concept. Several scholars see narratives as the most important way in which we make sense of experience. Personal narratives provide rich material for mapping the interconnections between individual and culture. As a form of thought, narrative marries singular circumstances with shared expectations and understandings that are learned through participation in a specific culture (Garro & Mattingly 2000). This study attempts to capture the cultural dimension of narrative with the concept of script , which originates in cognitive science (Schank & Abelson 1977) and has recently been adopted to narratology (Herman 2002). Script refers to a data structure that informs how events usually unfold in certain situations. Scripts are used in interpreting events and representing them verbally to others. They are based on dominant forms of knowledge that vary according to time and place. The questions that were posed in this study are the following. What kind of experiences bereaved daughters narrate? What kind of cultural scripts they employ as they attempt to make sense of these experiences? How these scripts are used in their narratives? It became apparent that for the most of the daughters interviewed in this study the single most important part of the bereavement narrative was to form an account of how and why the parent died. They produced lengthy and detailed descriptions of the last stage of a parent s life in contrast with the rest of the interview. These stories took their start from a turn in the parent s physical condition, from which the dying process could in retrospect be seen to have started, and which often took place several years before the death. In addition, daughters also talked about their grief reactions and how they have adjusted to a life without the deceased parent. The ways in which the last stage of life was told reflect not only the characteristic features of late modernity but also processes of marginalisation and exclusion. Revivalist script and medical script, identified by Clive Seale as the dominant, competing models for dying well in the late modern societies, were not widely utilised in the narratives. They could only be applied in situations in which the parent had died from cancer and at somewhat younger age than the average. Death that took place in deep old age was told in a different way. The lack of positive models for narrating this kind of death was acknowledged in the study. This can be seen as a symptom of the societal devaluing of the deaths of older people and it affects also daughters accounts of their grief. Several daughters told about situations in which their loss, although subjectively experienced, was nonetheless denied by other people.

Kansallisen konsensuskulttuurin jäljillä : Globalisaatioajan Suomi Helsingin Sanomissa

The dissertation analyzes Finnish consensual culture in public discussion and journalism in Helsingin Sanomat (HS). The consensual Finnish political culture has evolved and persisted over a long period of time and it has been affected by historical circumstances as well as the dynamics of political and journalistic structures and actors. A historical chronology is drawn in the study regarding the nature and development of consensus culture in 20th century Finland. This political culture is traced by looking at public discussion on globalization at the turn of the millennium. Globalization as a concept has been contested and various societal actors have given different meanings to it. This research looks at how the globalization discussion in HS during the years 1992-2004 constructs consensus. Helsingin Sanomat (and its predecessor Päivälehti) has been an important actor in Finnish journalism and the public sphere almost since its founding 120 years ago. The history of the paper is tightly connected to Finland s general political history and history of the public sphere. Moreover, the paper s connections to the societal elite have always been close. The central question in this research was to see how the globalization discussion in HS evolved in relation to consensus as well as legitimate controversies. As a result it is stated that the globalization question has clearly divided the Finnish societal actors. The most powerful societal elites (government, most civil servants, corporate sector) had a profile of being pro globalization. They communicated their globalization strategy as a national, unified way of thinking. Other elites which have been losing their influence (the president, labor union, part of members of parliament), as well as civil society actors tried to bring forward conflicting views in relation to globalization. The paper did give some room to these elements, but on the other hand it also tried to keep up the consensual discussion culture especially in the editorial section. In line with its traditions Helsingin Sanomat strived to create national unity. At the same time it did not give adequate attention to the changes brought about by globalization to the positions and roles of various elites and civil society actors. In this discussion HS seemed more like a medium of the state than as a critical and independent actor. Journalism has an important role in upholding and also reviving the Finnish political culture and public discussion. From this point of view it is problematic if the area of so called legitimate controversy in broad societal questions like globalization becomes very limited. As the Finnish elites are small and there is no considerable competition between them, journalism should actively bring up controversial issues. This task becomes complicated, however, if the elite circles are closed up and no initiatives come from their ranks. Political decision making as well as democracy can suffer, if issues are not brought to the public agenda.

Neighborhood Shopkeepers in Contemporary South Korea: Household, Work, and Locality

This is an ethnographic study of the lived worlds of the keepers of small shops in a residential neighborhood in Seoul, South Korea. It outlines, discusses, and analyses the categories and conceptualizations of South Korean capitalism at the level of households, neighborhoods, and Korean society. These cultural categories were investigated through the neighborhood shopkeepers practices of work and reciprocal interaction as well as through the shopkeepers articulations of their lived experience. In South Korea, the keepers of small businesses have continued to be a large occupational category despite of societal and economic changes, occupying approximately one fourth of the population in active work force. In spite of that, these people, their livelihoods and their cultural and social worlds have rarely been in the focus of social science inquiry. The ethnographic field research for this study was conducted during a 14-month period between November 1998 and December 1999 and in three subsequent short visits to Korea and to the research neighborhood. The fieldwork was conducted during the aftermath of the Asian currency crisis, colloquially termed at the time as the IMF crisis, which highlighted the social and cultural circumstances of small businesskeeper in a specific way. The livelihoods of small-scale entrepreneurs became even more precarious than before; self-employment became an involuntary choice for many middle-class salaried employees who were laid off; and the cultural categories and concepts of society and economy South Korean capitalism were articulated more sharply than before. This study begins with an overview of the contemporary setting, the Korean society under the socially and economically painful outcomes of the economic crisis, and continues with an overview of relevant literature. After introducing the research area and the informants, I discuss the Korean notion of neighborhood, which incorporates both the notions of culturally valued Koreanness and deficiency in the sense of modernity and development. This study further analyses the ways in which the businesskeepers appropriate and reproduce the Korean ideas of men s and women s gender roles and spheres of work. As the appropriation of children s labor is conditional to intergenerational family trajectories which aim not to reproduce parents occupational status but to gain entry to salaried occupations via educational credentials, the work of a married couple is the most common organization of work in small businesses, to which the Korean ideas of family and kin continuity are not applied. While the lack of generational businesskeeping succession suggests that the proprietors mainly subscribe to the notions of familial status that emanate from the practices of the white-collar middle class, the cases of certain women shopkeepers show that their proprietorship and the ensuing economic standing in the family prompts and invites inversed interpretations and uses of common cultural notions of gender. After discussing and analyzing the concept of money and the cultural categorization of leisure and work, topics that emerged as very significant in the lived world of the shopkeepers, this study charts and analyses the categories of identification which the shopkeepers employ for their cultural and social locations and identities. Particular attention is paid to the idea of ordinary people (seomin), which shopkeepers are commonly considered to be most representative of, and which also sums up the ambivalence of neighborhood shopkeepers as a social category: they are not committed to familial reproduction and continuity of the business but aspire non-entrepreneurial careers for their children, while they occupy a significant position in the elaborations of culturally valued notions and ideologies defining Koreanness such as warmheartedness and sociability.

Physicochemical, spectroscopic and electrochemical characterization of magnesium ion-conducting, room temperature, ternary molten electrolytes

Room temperature, magnesium ion-conducting molten electrolytes are prepared using a combination of acetamide, urea and magnesium triflate or magnesium perchlorate. The molten liquids show high ionic conductivity, of the order of mS cm(-1) at 298 K. Vibrational spectroscopic studies based on triflate/perchlorate bands reveal that the free ion concentration is higher than that of ion-pairs and aggregates in the melt. Electrochemical reversibility of magnesium deposition and dissolution is demonstrated using cyclic voltammetry and impedance studies. The transport number of Mg2+ ion determined by means of a combination of d.c. and ac. techniques is similar to 0.40. Preliminary studies on the battery characteristics reveal good capacity for the magnesium rechargeable cell and open up the possibility of using this unique class of acetamide-based room temperature molten electrolytes in secondary magnesium batteries. (C) 2010 Elsevier B.V. All rights reserved.

Itämafia : Uhkakuvapolitiikka, rikosilmiöt ja kulttuuriset merkitykset

The Eastern Mafia Threat policy, crime phenomena, and cultural meanings An interdisciplinary research on the crime phenomena and the threat policy relating to the organized crime and the mafia of Russia and Estonia is based on 151 expert interviews, statistics, documents, research literature, and press material. The main part of the material consists of interviews of the Finnish, Estonian and Russian police authorities specialized in the problem of organized crime, and the reports on the crime situation drawn up in the Finnish diplomatic representations in Tallinn and St Petersburg. The interviews have been gathered in the years 1996-2001. The main theoretical tools of the research are constructivist research on social problems, and political psychology. Definitional processes of social problems and cultural semantic structures behind them are identified in the analysis and connected to the analysis of the crime cases. Both in the Anglo-American and Russian cultural frames there appears an inflated and exaggerated talk, according to which the mafia rules everything in Russia and is spreading everywhere. There is the traditional anti-Semitic paranoia in the core of this cultural symbiosis produced by Russian legal nihilism, the theory of totalitarianism of Sovietology, and the inertia of Russian anti-capitalism. To equate the Sicilian Mafia with Russia is an anachronism, since no empirical proof of systematic uncontrolled violence or absolute power vacuum in Russia can be found. In the Anglo-American policy of threat images, "the Russian mafia" was seen as a commodified conspiracy theory, which the police, the media, and the research took advantage of, blurring the line between fact and fiction. In Finland, the evolution of the policy of threat images proceeded in three phases: Initially, extensive rolling of refugees and criminals from Russia to Finland was emphasized in the beginning of the 1990's. In the second phase, the eastern mafia was said to infiltrate all over Finnish society and administration. Finland was, however, found immune to this kind of spreading. In the third phase, in the 21st century, the organized crime of Finland was said to be lead from abroad. In Finland, the policy of threat images was especially canalised to moral panics connected to "eastern prostitution". In Estonia, the policy of threat images emphasized the crime organized by the Russian authorities and politicians in order to weaken Estonia. In Russia, the policy of threat images emphasized the total criminalizing of society caused by criminal capitalism. In every country, the policy of threat images was affected by a so-called large-group identity, a term by Vamik Volkan, in which a so-called chosen trauma caused a political paranoia of an outer and inner danger. In Finland, procuring, car theft, and narcotics crimes were at their widest arranged by the Finnish often with the help of the Estonians. The Russians had no influence in the most serious violent crimes in Finland, although the number of assassinations were at least 5, 000 in Russia in the 1990's. In Russia, the assassinations were on one hand connected to marital problems, on the other hand to the pursuit of public attention and a hoped-for effect by the aid of the murder of an influential person. In the white-collar crime phenomena between Finland and Russia, the Finnish state and Finnish corporations gained remarkable benefit of the frauds aimed at the states of the Soviet Union and Russia in 1980's-21st century. The situation of Estonia was very difficult compared to that of Russia in the 1990's, which was manifested in the stagnation of the Estonian police and judicial authorities, the crimes of the police and the voluntary paramilitary organization, bomb explosions, the rebellion called "the jaeger crisis" in the voluntary paramilitary organization, and the "blood autumn" of Eastern Virumaa, in other words terror. The situation of Estonia had a powerful effect on the crime situation of Finland and on the security of the Finnish diplomats. In the continuum of the Finnish policy of threat images, Russia and the Russians were, however, presented as a source of a marked danger.

How Kings are Made, How Kingship Changes : A Study of Ritual and Ritual Change in Pre-Colonial Owamboland, Namibia

This study discusses the legitimacy basis of political power and its changes in historical African societies. It starts from Luc de Heusch s tenet that political power required a legitimacy basis of a spiritual kind, often formulated as sacred kingship. In ancient and pre-literate societies such kings were held to be responsible for the fertility of man, land and cattle. The king was a paradoxical figure, symbolising society, but standing above it, while simultaneously being its victim by being ritually killed at old age. This was also how Owambo sacred kings were conceived. De Heusch suggested that African kings derived their power over fertility from having been made sacred monsters in the rituals of installation. With the example of Owambo kingship, this study argues that the transgressive and monstrous aspect is only one of several dimension of a king s sacredness and brings out the nurturing and symbolically female aspect, identified but not analysed further by de Heusch. In the Owambo kingly installation a king-elect was made sacred, and part of it was that a link was ritually created to the early owners of the land. Their consent made it possible for the king to promote fertility and to appropriate power emblems needed for ruling. In the kingdom of Ondonga the early owners of the land were the spirits of early Bushman inhabitants and those of an early kingly clan, both neglected in public memory. The sacred dimension of kingship was further augmented when kings manipulated and appropriated rain rituals and initiation rituals, both of which were related to fertility. The study argues that even though there were aspects of the sacred monster in Owambo kingship, its manifestation was, in part, a distortion of the reciprocal aspect of kingship that was expressed in the homage paid to various ancestor spirits. A change in succession practices from ritual regicide to political assassination took place concomitant with the introduction of firearms, and this broke the sacrificial aspect of sacred kingship paving the way for a more predatory form of kingship while the sacred status of the king was retained.

Studies on Binary Time Series Models with Applications to Empirical Macroeconomics and Finance

This thesis studies binary time series models and their applications in empirical macroeconomics and finance. In addition to previously suggested models, new dynamic extensions are proposed to the static probit model commonly used in the previous literature. In particular, we are interested in probit models with an autoregressive model structure. In Chapter 2, the main objective is to compare the predictive performance of the static and dynamic probit models in forecasting the U.S. and German business cycle recession periods. Financial variables, such as interest rates and stock market returns, are used as predictive variables. The empirical results suggest that the recession periods are predictable and dynamic probit models, especially models with the autoregressive structure, outperform the static model. Chapter 3 proposes a Lagrange Multiplier (LM) test for the usefulness of the autoregressive structure of the probit model. The finite sample properties of the LM test are considered with simulation experiments. Results indicate that the two alternative LM test statistics have reasonable size and power in large samples. In small samples, a parametric bootstrap method is suggested to obtain approximately correct size. In Chapter 4, the predictive power of dynamic probit models in predicting the direction of stock market returns are examined. The novel idea is to use recession forecast (see Chapter 2) as a predictor of the stock return sign. The evidence suggests that the signs of the U.S. excess stock returns over the risk-free return are predictable both in and out of sample. The new "error correction" probit model yields the best forecasts and it also outperforms other predictive models, such as ARMAX models, in terms of statistical and economic goodness-of-fit measures. Chapter 5 generalizes the analysis of univariate models considered in Chapters 2 4 to the case of a bivariate model. A new bivariate autoregressive probit model is applied to predict the current state of the U.S. business cycle and growth rate cycle periods. Evidence of predictability of both cycle indicators is obtained and the bivariate model is found to outperform the univariate models in terms of predictive power.

Structure and optical properties of Cd-substituted ZnO (Zn1-xCdxO) nanostructures synthesized by the high-pressure solution route

We report the synthesis of Cd-substituted ZnO nanostructures (Zn1-xCdxO with x up to approximate to 0.09) by the high-pressure solution growth method. The synthesized nanostructures comprise nanocrystals that are both particles (similar to 10-15 nm) and rods which grow along the [002] direction as established by transmission electron microscope (TEM) and x-ray diffraction (XRD) analysis. Rietveld analysis of the XRD data shows a monotonic increase of the unit cell volume with the increase of Cd concentration. The optical absorption, as well as the photoluminescence (PL), shows a red shift on Cd substitution. The line width of the PL spectrum is related to the strain inhomogeneity and it peaks in the region where the CdO phase separates from the Zn1-xCdxO nanostructures. The time-resolved photoemission showed a long-lived (similar to 10 ns) component. We propose that the PL behaviour of the Zn1-xCdxO is dominated by strain in the sample with the red shift of the PL linked to the expansion of the unit cell volume on Cd substitution.

Emotional experience in psychotherapeutic interaction : Conversation analytical study on cognitive psychotherapy

The dissertation examines how emotional experiences are oriented to in the details of psychotherapeutic interaction. The data (57 audio recorded sessions) come from one therapist-patient dyad in cognitive psychotherapy. Conversation analysis is used as method. The dissertation consists of 4 original articles and a summary. The analyses explicate the therapist s practices of responding to the patient s affective expressions. Different types of affiliating responses are identified. It is shown that the affiliating responses are combined with, or build grounds for, more interpretive and challenging actions. The study also includes a case study of a session with strong misalignment between the therapist s and patient s orientations, showing how this misalignment is managed by the therapist. Moreover, through a longitudinal analysis of the transformation of a sequence type, the study suggests that therapeutic change processes can be located to sequential relations of actions. The practices found in this study are compared to earlier research on everyday talk and on medical encounters. It is suggested that in psychotherapeutic interaction, the generic norms of interaction considering affiliation and epistemic access, are modified for the purposes of therapeutic work. The study also shows that the practices of responding to emotional experience in psychotherapy can deviate from the everyday practices of affiliation. The results of the study are also discussed in terms of concepts arising from clinical theory. These include empathy, validation of emotion, therapeutic alliance, interpretation, challenging beliefs, and therapeutic change. The therapist s approach described in this study involves practical integration of different clinical theories. In general terms, the study suggests that in the details of interaction, psychotherapy recurrently performs a dual task of empathy and challenging in relation to the patient s ways of describing their experiences. Methodologically, the study discusses the problem of identifying actions in conversation analysis of psychotherapy and emotional interaction, and the possibility to apply conversation analysis in the study of therapeutic change.

Retirement Transition and Well-being : A 16-year Longitudinal Study

The ageing of the labour force and falling employment rates have forced policy makers in industrialized countries to find means of increasing the well-being of older workers and of lengthening their work careers. The main objective of this thesis was to study longitudinally how health, functional capacity, subjective well-being, and lifestyle change as people grow older, and what effect retirement has on these factors and on their relationships. The present study is a follow-up questionnaire study of Finnish municipal workers, conducted in 1981 to 1997 at the Finnish Institute of Occupational Health. In 1981, a postal questionnaire was sent to 7344 municipal workers in different parts of Finland. The respondents were born between 1923 and 1937. A total of 6257 persons responded to the first questionnaire. In the end, a total of 3817 persons had responded to all four (1981, 1985, 1992, 1997) questionnaires. (The response rate was 69% of the living participants). Cross-tabulations, comparison of means, logistic regression analyses and general linear models with repeated measures were used to derive the results. The transition from work life to retirement, and the following years as a pensioner were associated with many changes. Involvement in various activities increased during the transition stage but later decreased to the previous level. Physical exercise was an exception: it became increasingly popular over the years. Perceived health improved markedly from the working stage to the retirement transition stage, even though morbidity increased steadily during the follow-up. On the other hand, functional capacity decreased over the follow-up, especially among those who were occupationally active until the retirement stage. Subjective well-being remained stable during the follow-up period. There were, however, great differences based on the type of work, favouring those whose work had been mental in nature. The impact of activity level on maintaining well-being became greater during the follow-up, whereas the effect of physical functioning diminished. Good physical functioning and an active life-style contributed to staying on at work until normal retirement age. Also work-related factors, i.e. possibilities for development and influence at work, responsibility for others, meaningful work, and satisfaction with working time arrangements were positively related to continuing working. The transition from work to retirement had a positive impact on a person s health and functional capacity. The study results support the view that it should be possible to ease one s work pace during the last years of a work career. This might lower the threshold between work and retirement and convince people that there will still be time to enjoy retirement also a few years later.