Learning Nonlinear Visual Processing from Natural Images

The paradigm of computational vision hypothesizes that any visual function -- such as the recognition of your grandparent -- can be replicated by computational processing of the visual input. What are these computations that the brain performs? What should or could they be? Working on the latter question, this dissertation takes the statistical approach, where the suitable computations are attempted to be learned from the natural visual data itself. In particular, we empirically study the computational processing that emerges from the statistical properties of the visual world and the constraints and objectives specified for the learning process. This thesis consists of an introduction and 7 peer-reviewed publications, where the purpose of the introduction is to illustrate the area of study to a reader who is not familiar with computational vision research. In the scope of the introduction, we will briefly overview the primary challenges to visual processing, as well as recall some of the current opinions on visual processing in the early visual systems of animals. Next, we describe the methodology we have used in our research, and discuss the presented results. We have included some additional remarks, speculations and conclusions to this discussion that were not featured in the original publications. We present the following results in the publications of this thesis. First, we empirically demonstrate that luminance and contrast are strongly dependent in natural images, contradicting previous theories suggesting that luminance and contrast were processed separately in natural systems due to their independence in the visual data. Second, we show that simple cell -like receptive fields of the primary visual cortex can be learned in the nonlinear contrast domain by maximization of independence. Further, we provide first-time reports of the emergence of conjunctive (corner-detecting) and subtractive (opponent orientation) processing due to nonlinear projection pursuit with simple objective functions related to sparseness and response energy optimization. Then, we show that attempting to extract independent components of nonlinear histogram statistics of a biologically plausible representation leads to projection directions that appear to differentiate between visual contexts. Such processing might be applicable for priming, \ie the selection and tuning of later visual processing. We continue by showing that a different kind of thresholded low-frequency priming can be learned and used to make object detection faster with little loss in accuracy. Finally, we show that in a computational object detection setting, nonlinearly gain-controlled visual features of medium complexity can be acquired sequentially as images are encountered and discarded. We present two online algorithms to perform this feature selection, and propose the idea that for artificial systems, some processing mechanisms could be selectable from the environment without optimizing the mechanisms themselves. In summary, this thesis explores learning visual processing on several levels. The learning can be understood as interplay of input data, model structures, learning objectives, and estimation algorithms. The presented work adds to the growing body of evidence showing that statistical methods can be used to acquire intuitively meaningful visual processing mechanisms. The work also presents some predictions and ideas regarding biological visual processing.

From Francovich to Köbler and beyond : The evolution of a State liability regime for the EC

The aim of this paper is to present the evolution of the Francovich doctrine within the European legal order. The first part deals with the gradual development of the ECJ's case law on State liability in damages for breach of EC law. Starting from the seminal Francovich and Brasserie du Pêcheur, the clarification of the criteria set by the Court is attempted with reference to subsequent case law, whereas issues concerning the extent and form of the compensation owned are also mentioned. The second part concerns one of the more recent developments in the field, namely State liability for breaches of Community law attributed to national judiciary. The Court's ruling in Köbler is examined in connection with two other recent judgments, namely Commission v. Italy of 2003 and Kühne & Heitz, as an attempt of the ECJ to reframe its relationships with national supreme courts and appropriate for itself the position of the Supreme Court in the European legal order. The implications on State liability claims by the ruling in Commission v. France of 1997 constitute the theme of the third part, where it is submitted that Member States can also be held liable for disregard of Community law by private individuals within their respected territories. To this extent, Schmidberger is viewed as a manifestation of this opinion, with fundamental rights acquiring a new dimension, being invoked by the States, contra the individuals as a shield to liability claims. Finally, the third part examines the relationship between the Francovich doctrine and the principle of legal certainty and concludes that the solutions employed by the ECJ have been both predictable and acceptable by the national legal orders. Keywords: State liability, damages, Francovich, Köbler, Schmidberger

Mikä on ihme ja mitä ihmeistä voidaan tietää? : Keskustelu ihmeistä uusimmassa englanninkielisessä uskonnonfilosofiassa

What is a miracle and what can we know about miracles? A discussion of miracles in anglophone philosophy of religion literature since the late 1960s. The aim of this study is to systematically describe and philosophically examine the anglophone discussion on the subject of miracles since the latter half of the 1960s. The study focuses on two salient questions: firstly, what I will term the conceptual-ontological question of the extent to which we can understand miracles and, secondly, the epistemological question of what we can know about miracles. My main purpose in this study is to examine the various viewpoints that have been submitted in relation to these questions, how they have been argued and on what presuppositions these arguments have been based. In conducting the study, the most salient dimension of the various discussions was found to relate to epistemological questions. In this regard, there was a notable confrontation between those scholars who accept miracles and those who are sceptical of them. On the conceptual-ontological side I recognised several different ways of expressing the concept of miracle . I systematised the discussion by demonstrating the philosophical boundaries between these various opinions. The first and main boundary was related to ontological knowledge. On one side of this boundary I placed the views which were based on realism and objectivism. The proponents of this view assumed that miraculousness is a real property of a miraculous event regardless of how we can perceive it. On the other side I put the views which tried to define miraculousness in terms of subjectivity, contextuality and epistemicity. Another essential boundary which shed light on the conceptual-ontological discussion was drawn in relation to two main views of nature. The realistic-particularistic view regards nature as a certain part of reality. The adherents of this presupposition postulate a supernatural sphere alongside nature. Alternatively, the nominalist-universalist view understands nature without this kind of division. Nature is understood as the entire and infinite universe; the whole of reality. Other, less important boundaries which shed light on the conceptual-ontological discussion were noted in relation to views regarding the laws of nature, for example. I recognised that the most important differences between the epistemological approaches were in the different views of justification, rationality, truth and science. The epistemological discussion was divided into two sides, distinguished by their differing assumptions in relation to the need for evidence. Adherents of the first (and noticeably smaller) group did not see any epistemological need to reach a universal and common opinion about miracles. I discovered that these kinds of views, which I called non-objectivist, had subjectivist and so-called collectivist views of justification and a contextualist view of rationality. The second (and larger) group was mainly interested in discerning the grounds upon which to establish an objective and conclusive common view in relation to the epistemology of miracles. I called this kind of discussion an objectivist discussion and this kind of approach an evidentialist approach. Most of the evidentialists tried to defend miracles and the others attempted to offer evidence against miracles. Amongst both sides, there were many different variations according to emphasis and assumption over how they saw the possibilities to prove their own view. The common characteristic in all forms of evidentialism was a commitment to an objectivist notion of rationality and a universalistic notion of justification. Most evidentialists put their confidence in science in one way or another. Only a couple of philosophers represented the most moderate version of evidentialism; they tried to remove themselves from the apparent controversy and contextualised the different opinions in order to make some critical comments on them. I called this kind of approach a contextualising form of evidentialism. In the final part of the epistemological chapter, I examined the discussion about the evidential value of miracles, but nothing substantially new was discovered concerning the epistemological views of the authors.

A role to play: Investigating concepts of masculinity in Australia through theatre

Health professionals, academics, social commentators and the media are increasingly sending the same message – Australian men are in crisis. This message has been supported by documented rises in alcoholism, violence, depression, suicide and crime amongst men in Australia. A major cause of this crisis, it can be argued, is an over-reliance on the out-dated and limited model of hegemonic masculinity that all men are encouraged to imitate in their own behaviour. This paper, as part of a larger study, explores representations of masculinity in selected works of contemporary Australian theatre in order to investigate the concept of hegemonic masculinity and any influence it may have on the perceived ‘crisis of masculinity’. Theatre is but one of the artistic modes that can be used to investigate masculinity and issues associated with identity. The Australia Council for the Arts recognises theatre, along with literature, dance, film, television, inter-arts, music and visual arts, as critical to the understanding and expression of Australian culture and identity. Theatre has been chosen in this instance because of the opportunities available to this study for direct access to specific theatre performances and creators and, also, because of the researcher’s experience, as a theatre director, with the dramatic arts. Through interviews with writers, directors and actors, combined with the analysis of scripts, academic writings, reviews, articles, programmes, play rehearsals and workshops, this research utilises theatre as a medium to explore masculinity in Australia.

Kirkon vai valtion kirjat? : Uskontokuntasidonnaisuuden ongelma Suomen väestökirjanpidossa 1839-1904

The Population Register – run by the Church or the state? The problem posed by the obligation to belong to a religious community in the registration of births and deaths in Finland between 1839 and 1904 The Lutheran Church of Finland is the nation’s largest church; approximately 82 per cent of Finns were members in 2007. The Church ran an official register of its members until 1999, when the state then undertook this task. The registration of births and deaths by the Church has a long history dating back to the 17th century, when Bishop Johannes Gezelius Sr. decreed that all parish members would have to be recorded in parish registers. These registers were used to control how well parish members knew the Christian doctrine and, gradually, also if they were literate. Additionally, the Church attempted to ensure by means of the parish registers that parish members went to Holy Communion annually. Since everyone was a member of the Lutheran Church, the state also took advantage of the parish registers and used them for the purposes of tax collection and conscription. The main research theme of “The Population Register – run by the Church or the state?” goes back to these times. The actual research period covers the years of 1839–1904. At that time Finland was under Russian rule, although autonomous. In the late 19th century the press and different associations in Finland began to engage in public debate, and the country started moving from a submissive society to a civic one. The identity of the Lutheran Church also became more prominent when the Church Act and the General Synod were realised in 1869. A few years earlier, municipal and parish administrations had been separated, but the general registration of births and deaths was left to the Church to see to. In compliance with the constitution of the country, all the inhabitants in principle still had to be Lutheran. In practice, the situation was different. The religious and ideological realms diversified, and the Lutheran concept of religion was no longer acceptable to everyone. The conflict was reflected in the registration of births and deaths, which was linked to the Lutheran Church and its parish registers. Nobody was allowed to leave the Church, there was no civil register, and the Lutheran Church did not consent to record unbaptized children in the parish registers. Therefore such children were left without civil rights. Thus the obligation to belong to a religious community had become a problem in the registration of births and deaths. The Lutheran clergy also appealed to the 1723 privileges, according to which they had been exempted from the drawing up of additional population registers. In 1889 Finland passed the Dissenters Act. By virtue of this act the Baptists and the Methodists left the state Church, but this was not the case with the members of the free churches. The freethinkers had to retain their church membership, as the law did not apply to them. This meant that the unbaptized children of the members of the free churches or those of freethinkers were still not entered in any registers. The children were not able to go to school, work for the state or legally marry. Neither were they able to inherit property, as they did not legally exist. The system of parish registers was created when everyone was required to be a member of the Lutheran Church, but it did not work when liberal attitudes eventually penetrated the sphere of religion, too. The government´s measures to solve the problem were slow and cautious, partly because Finland was part of Russia, partly because there were only about 100 unbaptized children. As the problem group was small and the state´s resources were limited, no general civil register was established. The state accepted the fact that in spite of the problems, the Evangelical Lutheran Church and the congregations of dissenters were the only official establishments to run populations registers in the country, and for social purposes, too. In 1900 the Diet of Finland finally approved a limited civil register, which unbaptized children and unregistered foreigners would be recorded in. Due to political reasons the civil register did not come into existence until 1917, after the actual research period.

Viimeinen matka : Toimintatutkimus kirkollisen hautauskentän professiostruktuurista

This study is a qualitative examination of the professional structure of the ecclesias-tical funeral field. The research material is based on 13 funeral cases in the archdio-cese. The researcher participated in all the funerals and memorial events, interviewed the closest survivors, the officials of the funeral agency and the ecclesiastical actors. The material was collected by means of observation and recording of the interviews, and was later transcribed and analyzed. The actors in this study are the survivors, the funeral agencies and the church. The survivors act as the buyers and users of the products (funeral services) who require both the funeral agencies and the church to assist them with the problems that the death has caused. The numbers of actions related to the death and to the funerals - the rituals of death - are placed on the action field, which in this study is called the funeral field. In this field, the researchquestion focused space and power, and the actions on the funeral field are highly ritualized. The theoretical model comes from Pierre Bourdieu. The study showed an action structure on the funeral field in which the survivors first contacted a funeral agency, which then contacted the other actors of the field, re-served the date and place for the funeral, and organised the funeral arrangements. The funeral agencies arranged an opportunity for the survivors to have a last look at the deceased when he or she was placed in the coffin, and they held a moment of the prayer (if desired) before removing the deceased from the hospital's chapel. The sur-vivors contacted the pastor of the funeral much later. The pastor also participated in the memorial event. The survivors contacted the church musician through via pastor. In some cases, the survivors had neither met nor even seen the musician prior to the actual funeral service. Still, the music was of great importance to the survivors. In the research interviews, tensions emerged to some extent between the funeral agencies and the ecclesiastical actors; these actors attempted to resolve these tensions through organising negotiations. In the beginning of the 20th century, the family took an active part in the preparations of the deceased and in the arrangements of the funerals, whereas this study showed that these days, survivors often transfer the preparations to the funeral agencies. The professional side of the funeral field has grown. The funeral agencies can be seen as providers of full services that act on the survivors' behalf, aspiring to high individu-ality and aiming to fulfil the survivors' wishes. In practise, the role of the church in carrying out the last journey was reduced in the research cases to the actual funeral. In several cases, the pastor or the cantor of the funeral had never before seen the per-son in the coffin at any stage of life or death. The proportion of cremations in funeral cases has increased rapidly, however, special issues related to these cremations (such as the possibility of holding a funeral service for the already cremated deceased) have seen little consideration in the church. In the church's liturgies on funeral rites, cremation is frequently overlooked. The pastors or the cantors did not participate in either the burial of the funeral urn or in the scattering of the deceased's ashes. The verger took care of it. The parishes had no adopted standard practices for cremations, yet in each case for the survivors that moment was crucial.

(Re)presenting Masculinity: A theatre director's critical observations of, and theatrical experimentation with, (re)presentations of masculinity in selected works of contemporary Australian theatre

Health professionals, academics, social commentators and the media are increasingly sending the same message – Australian men are in crisis. This message has been supported by documented rises in alcoholism, violence, depression, suicide and crime amongst men in Australia. A major cause of this crisis, it can be argued, is an over-reliance on the out-dated and limited model of hegemonic masculinity that all men are encouraged to imitate in their own behaviour. This paper, as part of a larger study, explores representations of masculinity in selected works of contemporary Australian theatre in order to investigate the concept of hegemonic masculinity and any influence it may have on the perceived ‘crisis of masculinity’. Theatre is but one of the artistic modes that can be used to investigate masculinity and issues associated with identity. The Australia Council for the Arts recognises theatre, along with literature, dance, film, television, inter-arts, music and visual arts, as critical to the understanding and expression of Australian culture and identity. Theatre has been chosen in this instance because of the opportunities available to this study for direct access to specific theatre performances and creators and, also, because of the researcher’s experience, as a theatre director, with the dramatic arts. Through interviews with writers, directors and actors, combined with the analysis of scripts, academic writings, reviews, articles, programmes, play rehearsals and workshops, this research utilises theatre as a medium to explore masculinity in Australia.

Orographic effects on the southwest monsoon: A review

An overview of the problem of orographic effects on the southwest monsoon using the contributions of all the available analytical and numerical models is attempted. A quasi-geostrophic model is applied to deduce the effect of the topographic complex on the Indian peninsula. This model suggests that the southward bending of the low-level isobars on the peninsula can be ascribed to the topographically-induced southward velocity. This southward velocity triggers a Rossby wave to the east of the peninsula which is manifested as a trough on the southern Bay of Bengal.

Expanding the research area of behavior change support systems

The First International Workshop on Behavior Change Support Systems attracted a great research interest. The selected papers focused on abstraction, implementation and evaluation of Behavior Change Support Systems. The workshop is an evidence of how researchers from around the globe have their own perspective of behavior change interventions. In this abstract, we have attempted to outline core issues that can enhance persuasiveness of such support systems. Finally, we highlight important research questions relating to the development of effective Behavior Change Support Systems.

The Population Consequences of Sex and Conflict

Natural selection generally operates at the level of the individual, or more specifically at the level of the gene. As a result, individual selection does not always favour traits which benefit the population or species as a whole. The spread of an individual gene may even act to the detriment of the organism in which it finds. Thus selection at the level of the individual can affect processes at the level of the organism, group or even at the level of the species. As most behaviours ultimately affect births, deaths and the distribution of individuals, it seems inevitable that behavioural decisions will have an impact on population dynamics and population densities. Behavioural decisions can often involve costs through allocation of energy into behavioural strategies, such as the investment into armaments involved in fighting over resources or increased mortality due to injury or increased predation risk. Similarly, behaviour may act o to benefit the population, in terms of higher survival and increased fecundity. Examples include increased investment through parental care, choosing a mate based on the nuptial gifts they may supply and choosing territories in the face of competition. Investigating the impact of behaviour on population ecology may seem like a trivial task, but it is likely to have important consequences at different levels. For example, antagonistic behaviour may occasionally become so extreme that it increases the risk of extinction, and such extinction risk may have important implications for conservation. As a corollary, any such behaviour may also act as a macroevolutionary force, weeding out populations with traits which, whilst beneficial to the individuals in the short term, ultimately result in population extinction. In this thesis, I examine how behaviours, specifically conflict and competition over a resource and aspects of behaviour involved in sexual selection, can affect population densities, and what the implications are for the evolution and ecology of the populations in question. It is found that both behaviours related to individual conflict and mating strategies can have an effect at the level of the population, but that various factors, such as a feedback between selection and population densities or macroevolution caused by species extinctions, may act to limit the intensity of conflicts that we observe in nature.

Synthetic polypeptide with antifreeze activity

MUCH information has been gathered in recent years on the so-called 'antifreeze' proteins which lower the freezing point of the serum of certain marine fishes living in sub-zero water temperatures1−4. The proteins from the Antarctic fish Trematomus borchgrevinki are glycoproteins with a repeating alanyl-alanyl-threonyl tripeptide sequence, the threonyl residue being linked to a disaccharide1,2. In contrast, the antifreeze protein from the winter flounder Pseudopleuronectus americanus in the North American Atlantic coastal region is made up of eight ammo acids with no apparent repeating sequence of the residues and no sugar moiety (ref. 4 and unpublished work of C. L. Hew, C. C. Yip & G. Fletcher). The antifreeze activity of these proteins is not compatible with the known colligative properties of solutes in solution and the mechanism of their action is not yet fully understood. But a common feature of both types of the antifreeze proteins is the preponderance of alanine which accounts for over 60% of the total amino residues. This fact, together with the absence of the carbohydrate in the protein from the winter flounder, prompted us to attempt the synthesis of polypeptide analogues having comparable proportions of alanine in them along with suitable other amino acids. As a first step, we made use of the lack of any obvious periodicity in the distribution of the alanyl residues in the flounder's protein and attempted the synthesis of a random copolypeptide containing about 65 mol % of alanine and 35 mol % of aspartic acid. The choice of aspartic acid was made on the basis of its being the next major amino acid in the flounder's protein3,4 and on the expectation that its polar character will help the water-solubility of the alanine-rich copolypeptide, as in other studies on alanine-containing random copolymers. In addition, Duman and DeVries4 have earlier indicated the involvement of carboxyl groups on the antifreeze activity by chemical modification studies. We report here the synthesis of this polypeptide and show that it possesses antifreeze activity.

Towards an evolving critical consciousness in coaching research: The physical pedagogic bricolage - A commentary

On a first reading of this article, one is struck by the complexity of language the authors use. Those of us who write in the social sciences and cultural studies are torn between the tenets of parsimony as present in the discourses of the natural sciences and the dangers of undertheorising our work. One assumes that there is a point that would be a happy medium. Finding that point often seems to be elusive. That said, I find the idea of linguistic sophistication to be appealing and in this sense the authors here have attempted to introduce new language into the world of sports coaching research through a process of reconceptualisation.

Antipredator behaviour of Baltic planktivores

Predation is an important source of mortality for most aquatic animals. Thus, the ability to avoid being eaten brings substantial fitness benefits to individuals. Predator detection abilities and antipredator behaviour were examined in various planktivores, i.e. the littoral mysids Neomysis integer and Praunus flexuosus, three-spined stickleback Gasterosteus aculeatus larvae, pelagic mysids Mysis mixta and M. relicta, and the predatory cladoceran Cercopagis pengoi, with cues from their respective predators European perch Perca fluviatilis and Baltic herring Clupea harengus membras. The use of different aquatic macrophytes as predation refuges by the littoral planktivores was also examined. All pelagic planktivores and stickleback larvae were able to detect the presence of their predator by chemical cues alone. The littoral mysids N. integer and P. flexuosus responded only when chemical and visual predator cues were combined. The responses of stickleback larvae were stronger to the combined cues than the chemical cue alone. A common antipredator behaviour in all of the planktivores studied was decreased ingestion rate in response to predator cues. N. integer and stickleback larvae also decreased their swimming activity. Pelagic mysids and C. pengoi altered their prey selectivity patterns in response to predator cues. The effects of predator cues on the swarming behaviour of N. integer were examined. Swarming brings clear antipredator advantages to N. integer, since when they feed in a swarm, they do not significantly decrease their feeding rate. However, the swarming behaviour of N. integer was not affected by predation risk, but was instead a fixed strategy. Despite the presence or absence of predator cues, N. integer individuals attempted to associate with a swarm and preferred larger to smaller swarms. In studies with aquatic macrophytes, stickleback larvae and P. flexuosus utilized vegetation as a predation refuge, spending more time within vegetation when under predation threat. The two macroalgal species studied, bladderwrack Fucus vesiculosus and stonewort Chara tomentosa, were preferred by P. flexuosus, whereas Eurasian watermilfoil Myriophyllum spicatum was strongly avoided by N. integer and stickleback larvae. In fact, when in dense patches in aquaria, M. spicatum caused acute and high mortality (> 70%) in littoral mysids, but not in sticklebacks, whereas C. tomentosa and northern watermilfoil M. sibiricum did not. In contrast, only 2-4% mortality in N. integer was observed with intact and broken stems of M. spicatum in field experiments. The distribution of littoral mysids in different vegetations, however, suggests that N. integer avoids areas vegetated by M. spicatum.

Mechanisms and molecular regulation of mammalian tooth replacement

In most non-mammalian vertebrates, such as fish and reptiles, teeth are replaced continuously. However, tooth replacement in most mammals, including human, takes place only once and further renewal is apparently inhibited. It is not known how tooth replacement is genetically regulated, and little is known on the physiological mechanism and evolutionary reduction of tooth replacement in mammals. In this study I have attempted to address these questions. In a rare human condition cleidocranial dysplasia, caused by a mutation in a Runt domain transcription factor Runx2, tooth replacement is continued. Runx2 mutant mice were used to investigate the molecular mechanisms of Runx2 function. Microarray analysis from dissected embryonic day 14 Runx2 mutant and wild type dental mesenchymes revealed many downstream targets of Runx2, which were validated using in situ hybridization and tissue culture methods. Wnt signaling inhibitor Dkk1 was identified as a candidate target, and in tissue culture conditions it was shown that Dkk1 is induced by FGF4 and this induction is Runx2 dependent. These experiments demonstrated a connection between Runx2, FGF and Wnt signaling in tooth development and possibly also in tooth replacement. The role of Wnt signaling in tooth replacement was further investigated by using a transgenic mouse model where Wnt signaling mediator β-catenin is continuously stabilized in dental epithelium. This stabilization led to activated Wnt signaling and to the formation of multiple enamel knots. In vitro and transplantation experiments were performed to examine the process of extra tooth formation. We showed that new teeth were continuously generated and that new teeth form from pre-existing teeth. A morphodynamic activator-inhibitor model was used to simulate enamel knot formation. By increasing the intrinsic production rate of the activator (β-catenin), the multiple enamel knot phenotype was reproduced by computer simulations. It was thus concluded that β-catenin acts as an upstream activator of enamel knots, closely linking Wnt signaling to the regulation of tooth renewal. As mice do not normally replace teeth, we used other model animals to investigate the physiological and genetic mechanisms of tooth replacement. Sorex araneus, the common shrew was earlier reported to have non-functional tooth replacement in all antemolar tooth positions. We showed by histological and gene expression studies that there is tooth replacement only in one position, the premolar 4 and that the deciduous tooth is diminished in size and disappears during embryogenesis without becoming functional. The growth rates of deciduous and permanent premolar 4 were measured and it was shown by competence inference that the early initiation of the replacement tooth in relation to the developmental stage of the deciduous tooth led to the inhibition of deciduous tooth morphogenesis. It was concluded that the evolutionary loss of deciduous teeth may involve the early activation of replacement teeth, which in turn suppress their predecessors. Mustela putorius furo, the ferret, has a dentition that resembles that of the human as ferrets have teeth that belong to all four tooth families, and all the antemolar teeth are replaced once. To investigate the replacement mechanism, histological serial sections from different embryonic stages were analyzed. It was noticed that tooth replacement is a process which involves the growth and detachment of the dental lamina from the lingual cervical loop of the deciduous tooth. Detachment of the deciduous tooth leads to a free successional dental lamina, which grows deeper into the mesenchyme, and later buds the replacement tooth. A careful 3D analysis of serial histological sections was performed and it was shown that replacement teeth are initiated from the successional dental lamina and not from the epithelium of the deciduous tooth. The molecular regulation of tooth replacement was studied and it was shown by examination of expression patterns of candidate regulatory genes that BMP/Wnt inhibitor Sostdc1 was strongly expressed in the buccal aspect of the dental lamina, and in the intersection between the detaching deciduous tooth and the successional dental lamina, suggesting a role for Sostdc1 in the process of detachment. Shh was expressed in the enamel knot and in the inner enamel epithelium in both generations of teeth supporting the view that the morphogenesis of both generations of teeth is regulated by similar mechanisms. In summary, histological and molecular studies on different model animals and transgenic mouse models were used to investigate tooth replacement. This thesis work has significantly contributed to the knowledge on the physiological mechanisms and molecular regulation of tooth replacement and its evolutionary suppression in mammals.

Work-related well-being of Finnish anesthesiologists

Anesthesiologists, according to some studies, are highly stressed, die at a significantly earlier age than their colleagues and the general population,and are among the leaders in physicians' suicide records. Data are,however, sparse and contradictory. The aim of this study was to discover details of the work-related well-being of Finnish anesthesiologists. In 2004, a cross-sectional postal survey including all 550 working Finnish anesthesiologists produced a total of 328 responses (60%); 53% were men. The anesthesiologists had the greatest on-call workload among Finnish physicians. Their average in-hospital on-call period lasted 24 hours (range 14 to 38). Over two-thirds felt stressed. The most important causes of stress were work and combining work with family. Their main worries at work were: excessive workload and time constraints, especially being on call, organizational problems, and fear of harming patients. On-call workload correlated with burnout. Being frequently on call was correlated with severe stress symptoms--symptoms associated with sick leaves. Women were more affected by stress than men. High job control and organizational justice seemed to mitigate hospital-on-call stress symptoms. The respondents enjoyed fairly high job and life satisfaction. Job control and organizational justice were the most important correlates of these wellness indicators. Work-related factors were more important in males, whereas family life played a larger role in the well-being of female anesthesiologists. Women had less job control, fewer permanent job contracts, and a higher domestic workload. Of the respondents, 31% were willing to consider changing to another physician's specialty and 43% to a profession other than medicine. The most important correlates for these job turnover attitudes were conflicts at the workplace, low job control, organizational injustice, stress, and job dissatisfaction. One in four had at some time considered suicide. Respondents with poor health, low social support, and family problems were at the highest risk for suicidality. The highest risks at work were conflicts with co-workers and superiors, on-call-related stress symptoms, and low organizational justice. If a respondent had several risk factors, the risk for suicidality doubled with each additional factor. On-call work-burden, job control, fairness of decision-making procedures,and workplace relationships should be the focus in attempts to increase the work-related well-being of anesthesiologists.