bluuebunny/crossref_metadata_2025 huggingface dataset:
I Can't Get No Satisfaction—Necessity Entrepreneurship and Procedural Utility
Authors: Block Joern , Koellinger Philipp
Published: April 2009

We study a unique sample of 1,547 nascent entrepreneurs in Germany and analyze which factors are associated with their self‐reported satisfaction regarding their start‐up. Our study identifies a new facet of procedural utility and offers new insights about the motivations and goals of nascent entrepreneurs. Most importantly, we identify a group of nascent entrepreneurs that ‘cannot get satisfaction’ with their start‐up—not because their start‐up fails to deliver financial returns, but because they did not choose to become entrepreneurs in the first place. This group of unsatisfied entrepreneurs includes individuals starting a business after a period of long‐term unemployment and those individuals with a lack of better employment alternatives (necessity entrepreneurs). In addition, we provide additional evidence for the importance of both financial and non‐financial incentives of entrepreneurs. While financial success is the most important determinant of start‐up satisfaction, achievement of independence and creativity is also highly important. Our results emphasize the relevance of procedural utility for understanding economic behavior. We show that the process leading to a decision has an impact on the later satisfaction with the outcome of that decision.
The Hedonics of Hedonism – Estimating the Value of Risk‐Taking Activities
Authors: Borsky Stefan , Raschky Paul A.
Published: April 2009

This paper estimates the individual willingness to pay (WTP) for the option to exercise risk‐taking. We use data of 69 Austrian Ski resorts and 3,637 reported ski accidents and apply the hedonic market method. Our results suggest that the individual WTP for a hypothetical increase in the possibility to undertake risk‐taking activities lies between 11% and 25% of the price of a ski‐lift‐ticket. Monetized values help design pricing schemes that set incentives to reduce risk‐taking behavior as well as to develop alternative instruments to reduce the adverse effects of risk‐taking activities (e.g. accidents).
The Impact of Foreign Direct Investment on Press Freedom
Authors: Dutta Nabamita , Roy Sanjukta
Published: April 2009

In our paper we establish foreign direct investment (FDI) as a major determinant of media freedom. Global integration can strengthen the media sector financially, make it technologically enhanced and can also improve the economic environment as a whole. This, in turn, would work towards the enhancement of media freedom. The sample includes high, middle and low income economies. Using a panel of 115 countries over a period of 20 years, our results reveal that FDI is an absolute necessity for a free and efficient media. The results are robust to various alternate specifications and inclusion of additional control variables.
Why Sociology is Better Conditioned to Explain Economic Behaviour than Economics
Authors: Folmer Henk
Published: April 2009

This note analyzes the impacts of the fragmentation of economics into different schools of thought and of social science into the sub‐disciplines economics, sociology and psychology. Fragmentation is based on the assumption that it is possible to split the set of an individual's behavioural motives into separable and disjoint subsets. However, this assumption runs counter to the insights in psychology. Moreover, even if splitting up were possible, the different subsets of motives finally need to be checked on consistency and weighted so as to obtain a comprehensive description and explanation. Another serious drawback is that specification of empirical models on the basis of one school of thought or one sub‐discipline leads to omitted variables bias and hence biased estimators and tests. Finally, fragmentation may lead to a ‘pick‐and‐mix package’, whereby policy‐makers and politicians feel free to use what suits them. The social rationality model together with the methodological approach prevalent in modern sociology is presented as a framework for integrating the schools of thought in economics and the social science sub‐disciplines.
Intergenerational Mobility and the Earnings Position of First‐, Second‐, and Third‐Generation Immigrants
Authors: Hammarstedt Mats
Published: April 2009

Immigrants' labour market situation has been in the focus of research in economics as well as in other sciences, and the labour market situation of immigrants and their children (i.e. first‐ and second‐generation immigrants) is relatively well documented in many countries today. However, less attention has up to now been paid to the labour market and earnings situation among the grandchildren of immigrants, i.e. third‐generation immigrants. Against this background, this paper studies intergenerational earnings mobility and the earnings position of three generations of immigrants in Sweden. The results indicate a regression towards the native earnings mean in immigrant earnings across the first two generations in the sense that immigrants earn more than natives in the first generation while there are small ethnic earnings in the second generation. Furthermore, immigrants earn less than natives in the third generation. Thus, the results suggest a downward trend in immigrants' relative earnings across generations. One conclusion of the study is that ethnic differences in earnings may occur beyond the second generation of immigrants and that the problem with integration of immigrants therefore may last for several generations.
Rubber Erasures, Rubber Producing Rights: Making Racialized Territories in West Kalimantan, Indonesia
Authors: Peluso Nancy Lee
Published: April 2009

This article makes connections between often‐disparate literatures on property, violence and identity, using the politics of rubber growing in West Kalimantan, Indonesia, as an example. It shows how rubber production gave rise to territorialities associated with and productive of ethnic identities, depending on both the political economies and cultural politics at play in different moments. What it meant to be Chinese and Dayak in colonial and post‐colonial Indonesia, as well as how categories of subjects and citizens were configured in the two respective periods, differentially affected both the formal property rights and the means of access to rubber and land in different parts of West Kalimantan. However, incremental changes in shifting rubber production practices were not the only means of producing territory and ethnicity. The author argues that violence ultimately played a more significant role in erasing prior identity‐based claims and establishing the controls of new actors over trees and land and their claims to legitimate access or ‘rightfulness’. Changing rubber production practices and reconfigurations of racialized territories and identity‐based property rights are all implicated in hiding the violence.
Authority over Forests: Empowerment and Subordination in Senegal's Democratic Decentralization
Authors: Ribot Jesse C.
Published: April 2009

Senegal's 1998 forestry code transfers rights to control and allocate forest access to elected rural councils, ostensibly giving the elected authorities significant material powers with respect to which they can represent the rural population. But the Forest Service is unwilling to allow rural councils to exercise these powers. To retain control, foresters use pressure, bribes and threats while taking advantage of the inability of the rural representatives to influence actors higher up in government. They justify themselves with arguments of national good and local incompetence. The foresters ally with urban‐based forest merchants and are supported by the sub‐prefect. Despite the transfer of forest rights, the foresters continue to allocate access to lucrative forest opportunities — in this case charcoal production and exchange — to the merchants. Despite holding effective property rights over forest, such as the right to exclude others, rural councils remain marginal and rural populations remain destitute. The councils cannot represent their populations and therefore cannot gain legitimacy: they have no authority. Despite progressive new laws, the Forest Service helps to maintain Senegal's healthy urban charcoal oligopsonies, while beating back fledgling local democracy.
Learning in 3‐D multiuser virtual environments: Exploring the use of unique 3‐D attributes for online problem‐based learning
Authors: Omale Nicholas , Hung Wei‐Chen , Luetkehans Lara , Cooke‐Plagwitz Jessamine
Published: April 2009

The purpose of this article is to present the results of a study conducted to investigate how the attributes of 3‐D technology such as avatars, 3‐D space, and comic style bubble dialogue boxes affect participants' social, cognitive, and teaching presences in a blended problem‐based learning environment. The community of inquiry model was adopted to analyse and interpret data collected from transcripts and group interviews. The results indicated that although the attributes of 3‐D technology promoted participants' social presence, this positive online social experience did not completely contribute to participants' cognitive presence due to inherent technology attributes. Additionally, critical technical and instructional features of the 3‐D environment were required in order to further enhance teaching presence and overall learning experience.
Developing the Media Zoo in Second Life
Authors: Wheeler Matthew
Published: April 2009

Second Life (SL), an immersive virtual environment, is increasingly being adopted in education for both formal and informal teaching and learning uses. This paper addresses the process of developing a demonstrator presence in SL, the potential of the system for formal teaching and some practical ideas on how to successfully integrate such emerging technologies into practice.
Socialisation for learning at a distance in a 3‐D multi‐user virtual environment
Authors: Edirisingha Palitha , Nie Ming , Pluciennik Mark , Young Ruth
Published: April 2009

This paper reports findings of a pilot study that examined the pedagogical potential of Second Life (SL), a popular three‐dimensional multi‐user virtual environment (3‐D MUVE) developed by the Linden Lab. The study is part of a 1‐year research and development project titled ‘Modelling of Secondlife Environments’ (http://www.le.ac.uk/moose) funded by the UK Joint Information Systems Committee. The research question addressed in this paper is: how can learning activities that facilitate social presence and foster socialisation among distance learners for collaborative learning be developed in SL, a 3‐D MUVE? The study was carried out at the University of Leicester (UoL) within an undergraduate module on Archaeological Theory, where two tutors and four students took part in four learning activities designed to take place in SL within the UoL Media Zoo island. The learning activities and training in SL were based on Salmon's five‐stage model of online learning. Students’ engagement in SL was studied through interviews, observations and records of chat logs. The data analysis offers four key findings in relation to the nature and pattern of in‐world ‘socialisation’ and its impact on real‐world network building; the pattern of in‐world ‘socialisation’ stage in Salmon's 5‐stage model; perspectives on students’ progress in‐world through the first stage of the model—‘access and motivation’—and perspectives on their entry into, and progress through, the second stage of the model—‘socialisation’—and the role of identity presented through avatars in the process of socialisation. The paper offers implications for research and practice in the light of these findings.
Why Do People Hurt Themselves?
Authors: Nock Matthew K.
Published: April 2009

Nonsuicidal self-injury (NSSI) is a prevalent but perplexing behavior problem in which people deliberately harm themselves without lethal intent. Research reveals that NSSI typically has its onset during early adolescence; most often involves cutting or carving the skin; and appears equally prevalent across sexes, ethnicities, and socioeconomic statuses. Less is known about why people engage in NSSI. This article presents a theoretical model of the development and maintenance of NSSI. Rather than a symptom of mental disorder, NSSI is conceptualized as a harmful behavior that can serve several intrapersonal (e.g., affect regulation) and interpersonal (e.g., help-seeking) functions. Risk of NSSI is increased by general factors that contribute to problems with affect regulation or interpersonal communication (e.g., childhood abuse) and by specific factors that influence the decision to use NSSI rather than some other behavior to serve these functions (e.g., social modeling). This model synthesizes research from several different areas of the literature and points toward several lines of research needed to further advance the understanding of why people hurt themselves.
Prediction Errors and Attention in the Presence and Absence of Feedback
Authors: Wills Andy J.
Published: April 2009

Contemporary theories of learning typically assume that learning is driven by prediction errors—in other words, that we learn more when our predictions turn out to be incorrect than we do when our predictions are correct. Results from the recording of electrical brain activity suggest one mechanism by which this might happen; we seem to direct visual attention toward the likely causes of previous prediction errors. This can happen very rapidly—within less than 200 milliseconds of the error-causing object being presented. It is tempting to infer that if learning is driven by prediction errors, then little can be learned in the absence of feedback. Such a conclusion is unwarranted. In fact, the substantial learning that is sometimes the result of simple exposure to objects can also be explained by processes of directing attention toward the likely causes of previous prediction errors.
What Do People Want to Feel and Why?
Authors: Tamir Maya
Published: April 2009

It is typically assumed that people always want to feel good. Recent evidence, however, demonstrates that people want to feel unpleasant emotions, such as anger or fear, when these emotions promote the attainment of their long-term goals. If emotions are regulated for instrumental reasons, people should want to feel pleasant emotions when immediate benefits outweigh future benefits, but when future benefits outweigh immediate benefits, people may prefer to feel useful emotions, even if they are unpleasant. In this article, I describe an instrumental account of emotion regulation, review empirical evidence relevant to it, and discuss its implications for promoting adaptive emotional experiences.
Bringing It All Back Home
Authors: Repetti Rena , Wang Shu-wen , Saxbe Darby
Published: April 2009

Families are dynamic systems that are permeable to influences from the outside world, such as daily stressors at work and at school. Our research uses naturalistic methods to investigate how family interactions change in response to such experiences and how other family members contribute to that process. We argue that the short-term effects of daily stressors on family dynamics can have cumulative, long-term implications for family health and functioning. Naturalistic studies that incorporate daily diary, observational, and physiological measures can offer new insights into families' everyday stress responding and coping processes.
The New Person-Specific Paradigm in Psychology
Authors: Molenaar Peter C.M. , Campbell Cynthia G.
Published: April 2009

Most research methodology in the behavioral sciences employs interindividual analyses, which provide information about the state of affairs of the population. However, as shown by classical mathematical-statistical theorems (the ergodic theorems), such analyses do not provide information for, and cannot be applied at, the level of the individual, except on rare occasions when the processes of interest meet certain stringent conditions. When psychological processes violate these conditions, the interindividual analyses that are now standardly applied have to be replaced by analysis of intraindividual variation in order to obtain valid results. Two illustrations involving analysis of intraindividual variation of personality and emotional processes are given.
Adult Attachment
Authors: Roisman Glenn I.
Published: April 2009

Attachment security in adulthood is not profitably conceptualized as a single, monolithic construct. It is reflected both in adults' confidence in themselves and others in close relationships (as noted by social-personality psychologists) and in their ability to successfully construct a coherent life narrative about childhood experiences with primary attachment figures (as emphasized by developmental psychologists). Evidence suggests that measures tapping these forms of attachment-related variation represent the underlying structure of adult attachment similarly, in that both may be best captured by two continuously distributed, albeit correlated dimensions tapping anxiety and avoidance. Nonetheless, differing approaches to measuring adult security demonstrate weak empirical overlap, and emerging evidence suggests that each is associated with personal and interpersonal outcomes central to attachment theory in empirically distinct ways. Discussion focuses on how recent insights—in combination with needed experimental and longitudinal data—can help reconcile the developmental- and social-psychological literatures on adult attachment.
Aid and the Soft Budget Constraint
Authors: Janus Thorsten
Published: April 2009

The author applies the theory of the soft budget constraint to explain some stylized facts regarding the outcomes and practice of international aid, including ineffectiveness, white elephants, and volatility. The soft budget constraint can also make aid counterproductive. Nonetheless, actual aid institutions may be constrained optimal responses to soft budgets and commonly suggested reforms such as improved donor coordination in aid, focus on fewer countries and projects, and less volatility of aid may lower the effectiveness of aid. The soft budget is also consistent with conservative project selection and the recent focus on “ownership.”
Remittances, Financial Market Development, and Economic Growth: The Case of Latin America and the Caribbean
Authors: Mundaca B. Gabriela
Published: April 2009

Within a theoretical framework, the author analyzes the effects that both workers' remittances and financial intermediation have on economic growth. It is found, among other things, that remittances can have significant positive long‐run effects on growth. The author confronts the implications of the theoretical model proposed with panel data for countries in Latin America and the Caribbean. After considering the effect of long‐run investment and demographic variables, and controlling for fixed time and country effects, the empirical analysis indicates that financial intermediation tends to increase the responsiveness of growth to remittances. The overall conclusion is that making financial services more generally available should lead to even better use of remittances, thus boosting growth in these countries.
Endogenous Financial and Trade Openness
Authors: Aizenman Joshua , Noy Ilan
Published: April 2009

The authors study the endogenous determination of financial and trade openness. They construct a theoretical framework leading to two‐way feedbacks between financial and trade openness and identify these feedbacks empirically. They find that one standard deviation increase in commercial openness is associated with a 9.5% increase in de facto financial openness (% of GDP). Similarly, an increase in de facto financial openness has powerful effects on future trade openness. De jure restrictions on capital mobility have only a weak impact on de facto financial openness, while de jure restrictions on the current account have a large adverse effect on commercial openness. The authors investigate the relative magnitudes of these directions of causality using Geweke's (1982) decomposition methodology. They conclude that in an era of rapidly growing trade integration, countries cannot choose financial openness independently of their degree of openness to trade. Dealing with greater exposure to turbulence by imposing restrictions on financial flows is likely to be ineffectual.
The Effect of Corruption on Investment Growth: Evidence from Firms in Latin America, Sub‐Saharan Africa, and Transition Countries*
Authors: Asiedu Elizabeth , Freeman James
Published: April 2009

Most of the empirical studies that analyze the impact of corruption on investment have three common features: they employ country‐level data on investment, corruption is measured at the country level, and data for countries from several regions are pooled together. This paper uses firm‐level data on investment and measures corruption at the firm and country level, and allows the effect of corruption to vary by region. Our dependent variable is firms' investment growth and we employ six measures of corruption from four different sources—two firm‐level measures and four country‐level measures. We find that the effect of corruption on investments varies significantly across regions: corruption has a negative and significant effect on investment growth for firms in Transition countries but has no significant impact for firms in Latin America and Sub‐Saharan Africa. Furthermore, for Transition countries, corruption is the most important determinant of investment.
Macroeconomic Uncertainty and Performance in Asian Countries*
Authors: Bredin Don , Elder John , Fountas Stilianos
Published: April 2009

We use a very general bivariate GARCH‐M model and quarterly data for five Asian countries to test for the impact of real and nominal macroeconomic uncertainty on inflation and output growth. We conclude the following. First, in the majority of countries uncertainty regarding the output growth rate is related negatively to the average growth rate. Secondly, contrary to expectations, inflation uncertainty in most cases does not harm the output growth performance of an economy. Thirdly, inflation and output uncertainty have a mixed effect on inflation. Consistent results are found using the VAR‐GARCH‐M approach to investigate the dynamic relationship between inflation and output growth using impulse response functions. This evidence implies that macroeconomic uncertainty may even improve macroeconomic performance, i.e. raise output growth and reduce inflation. Our empirical results highlight important differences with those for industrialized countries.
Do Multinational Enterprises Contribute to Convergence or Divergence? A Disaggregated Analysis of US FDI*
Authors: Mayer‐Foulkes David , Nunnenkamp Peter
Published: April 2009

It is widely held that foreign direct investment (FDI) has a positive effect on economic growth. To test this hypothesis, we perform convergence regressions derived from a theoretical model on the impact of FDI on endogenous technological change in small economies. The model includes FDI externalities that enhance growth, but also shows that FDI can crowd out host country income and reduce local innovation. The empirical analysis employs disaggregated US data for various FDI‐related activities—in addition to the conventionally used aggregate FDI stocks and flows. We estimate the net FDI impact on the convergence rate of per‐capita income to US levels, controlling for human development, financial development, and trade. We find that FDI accelerates convergence for high‐income countries only, otherwise slowing it down.
A Tale of Two Ports: The Economic Geography of Inter‐City Rivalry*
Authors: Long Ngo Van , Wong Kar‐yiu
Published: April 2009

This paper examines how two geographically separated ports compete for a market consisting of manufacturing firms located between them. There is a service firm in each port, and these two firms, taking the infrastructure provided by their governments as given, compete in prices. The governments compete in terms of investment in infrastructure. This paper shows that there are cases in which both the firm and the government in the port that has a longer history may have the first‐mover advantage. In particular, the government can provide a credible threat by overinvesting in infrastructure.
WTO as Moral Support
Authors: Furusawa Taiji
Published: April 2009

International cooperation in trade policies under the auspices of the WTO makes countries “feel” more obliged to uphold agreements. The paper emphasizes the role of the WTO to give moral support: countries incur “psychological costs” when they renege on the agreements that are formally signed under the WTO. Using the concept of Kandori's (2003) “morale equilibrium,” we formalize this idea and show that countries can agree on a cooperative level of the binding tariffs but they occasionally deviate from the agreement, which lowers the morale and invites further deviations in the future.
Chinese deaf adolescents’ free recall of taxonomic, slot‐filler, and thematic categories
Authors: LI DEGAO , ZHANG JIJIA
Published: April 2009

Four experiments were conducted to show that deaf adolescents tended to process information in different ways from hearing adolescents. Memorizing items sequentially shown on computer screens under the control of their articulators’ movements, deaf adolescents tended to treat items that cohered as taxonomic, thematic, or slot‐filler categories as isolated pieces of information. Having to perceive information by means of sign language, however, their achievements were not worse than those of hearing adolescents anymore, no matter whether the stimuli were presented as words or pictures. They could not only utilize categories relations to help memorize categories exemplars but were relatively better aware of slot‐filler or thematic than taxonomic relations as well, suggesting that they had a relatively delayed development of taxonomic category representations in comparison with hearing adolescents.
Statistics Online Computational Resource for Education
Authors: Dinov Ivo D. , Christou Nicolas
Published: April 2009

The Statistics Online Computational Resource (http://www.SOCR.ucla.edu) provides one of the largest collections of free Internet‐based resources for probability and statistics education. SOCR develops, validates and disseminates two core types of materials – instructional resources and computational libraries.
Development of letter position processing: effects of age and orthographic transparency
Authors: Ktori Maria , Pitchford Nicola J.
Published: April 2009

This study investigated the relative extent to which developing readers (6‐ and 9‐year‐olds) of English (deep) or Greek (transparent) orthography exhibit serial and exterior letter effects in letter position encoding. Participants were given a visual search task that required detection of a pre‐specified target letter within a random five‐letter string. Stimuli comprised letters either specific to English or Greek, or shared by both orthographies. For native letters, all readers showed significant initial‐letter facilitation. In contrast, final‐letter facilitation was shown only by English children. Furthermore, Greek 9‐year‐olds showed significantly more left‐to‐right facilitation than English 9‐year‐olds. These results suggest that letter position encoding is adaptive to the nature of the orthography acquired during reading development.
FAMILY POLICIES AND THE OPTIMAL POPULATION GROWTH RATE: CLOSED AND SMALL OPEN ECONOMIES
Authors: Fanti Luciano , Gori Luca
Published: April 2009

We re‐examine the issue of optimal population in the basic overlapping generations model of neoclassical growth with endogenous fertility and time cost of children in both closed and small open economies. In the former case, we show that the golden rule of population growth can be achieved by a benevolent government in a market setting whose purpose is to maximize the steady‐state individual lifetime welfare, using either a child subsidy or a child tax. In the latter case, the child subsidy (tax) can be used as an exclusive instrument to replicate the command optimum.
Fire and Ice: Unnatural Disasters and the Disposable Urban Poor in Post‐Apartheid Johannesburg
Authors: MURRAY MARTIN J.
Published: April 2009

Johannesburg is a divided city where propertied middle‐class residents and the urban poor live in existentially separate worlds. If the steady accretion of luxury entertainment sites, enclosed shopping malls and gated residential communities in the northern suburbs has come to symbolize the entry of middle‐class urbanites into the culture of aspirant ‘world class’ cities, then the proliferation of overcrowded, resource‐starved informal settlements on the periurban fringe represents the dystopian features of distressed urbanism. The risk‐prone environments of informal squatter settlements magnify the impact of catastrophic events like fires and floods, and the intersection of disaster‐vulnerable settlement patterns with relaxed planning regulations and building standards, lack of preparation for unsuspected calamities, and inadequate crisis management creates entirely new artificial hazards. These unnatural disasters cannot simply be attributed to ‘bad luck’ or nature's destructive force. Disaster‐vulnerability and exposure to risk are unevenly distributed across the metropolis. By focusing attention on the catastrophic fires that regularly destroy shanty settlements in places like Alexandra township at the northeast corner of Johannesburg, it is possible to reveal a largely hidden structure of marginality and social insecurity that is a permanent condition of everyday life for the urban poor.

Johannesburg est une ville divisée où habitants de la classe moyenne possédante et citadins pauvres vivent dans des univers d’existence séparés. Si l’augmentation régulière des lieux de distractions, centres commerciaux et enclaves privées sécurisées dans les banlieues Nord signe l’accès des citadins de la classe moyenne à la culture des villes candidates à‘l’échelon international’, la prolifération d’implantations sauvages surpeuplées et dépourvues de ressources à la limite périurbaine traduit les caractères dystopiques d’un urbanisme sinistré. Les environnements à risque des implantations sauvages des squatters amplifient l’impact des catastrophes telles que les incendies ou inondations, tandis que la conjonction entre modèles d’implantations à risque assortis de réglementations d’urbanisme et de normes de construction assouplies, préparation insuffisante à des calamités insoupçonnées et gestion inappropriée des crises, crée des risques artificiels totalement nouveaux. On ne peut attribuer ces désastres non naturels simplement à la malchance ou à la force destructrice de la nature. La vulnérabilité face aux catastrophes et l’exposition au risque ne se répartissent pas uniformément dans la métropole. En s’intéressant aux incendies qui ravagent régulièrement les bidonvilles existants, comme le township d’Alexandra dans la zone nord‐est de Johannesburg, on peut mettre à jour une structure quasi invisible de marginalité et d’insécurité sociale qui constitue un état permanent dans la vie quotidienne des citadins pauvres.
Urban Political Economy, ‘New Urban Politics’ and the Media: Insights and Limits
Authors: WARD KEVIN
Published: April 2009

This essay considers how a particular set of urban political literatures have dealt with the role of ‘the media’. I argue that they have tended to concentrate on ‘local’ newspapers and that the role of the media — rather than just that of local newspapers — remains under‐theorized.

Ce travail porte sur la façon dont un ensemble donné de textes de politique urbaine a traité le rôle des ‘médias’. L'auteur montre que ces textes se sont plutôt attachés aux journaux ‘locaux’ et que le rôle des médias – mais pas seulement celui des journaux locaux – reste peu théorisé.
The latent structure of child depression: a taxometric analysis
Authors: Richey J. Anthony , Schmidt Norman B. , Lonigan Christopher J. , Phillips Beth M. , Catanzaro Salvatore J. , Laurent Jeff , Gerhardstein Rebecca R. , Kotov Roman
Published: April 2009

Background:  The current study examined the categorical versus continuous nature of child and adolescent depression among three samples of children and adolescents ranging from 5 to 19 years.

Methods:  Depression was measured using the Children’s Depression Inventory (CDI). Indicators derived from the CDI were based on factor analytic research on the CDI and included indices of: 1) social withdrawal, 2) anhedonia, 3) incompetence/maladjustment and 4) negative self‐esteem.

Results:  Taxometric procedures provided convergent support for the existence of a latent taxon across three independent samples. Internal and external consistency tests as well as Monte Carlo simulations supported the validity of the results.

Conclusions:  Multiple nonredundant procedures and samples were all consistently indicative of taxonicity in child depression.
An fMRI investigation of the impact of withdrawal on regional brain activity during nicotine anticipation
Authors: Gloria Rebecca , Angelos Lisa , Schaefer Hillary S. , Davis James M. , Majeskie Matthew , Richmond Burke S. , Curtin John J. , Davidson Richard J. , Baker Timothy B.
Published: April 2009

Previous research indicates that drug motivational systems are instantiated in structures that process information related to incentive, motivational drive, memorial, motor/habit, craving, and cognitive control processing. The present research tests the hypothesis that activity in such systems will be powerfully affected by the combination of drug anticipation and drug withdrawal. Event‐related fMRI was used to examine activation in response to a preinfusion warning cue in two experimental sessions that manipulated withdrawal status. Significant cue‐induced effects were seen in the caudate, ventral anterior nucleus of the thalamus, the insula, subcallosal gyrus, nucleus accumbens, and anterior cingulate. These results suggest that withdrawal and nicotine anticipation produce (1) different motor preparatory and inhibitory response processing and (2) different craving related processing.
Is informed choice in prenatal testing universally valued? A population‐based survey in Europe and Asia
Authors: van den Heuvel A , Chitty L , Dormandy E , Newson A , Attwood S , Ma R , Masturzo B , Pajkrt E , Marteau TM
Published: April 2009

Objective Informed choice has become an integral part of healthcare provision. We investigated the extent to which informed choice in the context of prenatal testing is universally valued.

Design The value attached to parental choice in prenatal testing and the perceived importance of significant others’ views when making test decisions were assessed in a cross‐sectional, descriptive study.

Sample and setting Male and female participants from general population samples in six countries: the UK (n = 210), the Netherlands (n = 197), Italy (n = 200), Greece (n = 200), China (n = 200) and India (n = 199).

Methods The questionnaires assessed values attached to parental involvement and the perceived importance of the views of significant others when making prenatal test decisions.

Main outcome measures Attitudes towards parental choice and attitudes towards the importance of others’ views were analysed by age, gender and education using Chi‐squared tests, Analysis of Variances and multiple logistic regression.

Results The majority of respondents from Northern European countries believed that undergoing prenatal tests should reflect parental choice. Conversely, only a minority of respondents from Southern European and Asian countries advocated parental choice, with most expressing the belief that all pregnant women should have the procedure. The perceived importance of significant others’ views when making test decisions also varied across countries: those in favour of parental choice perceived others’ views as less important in the test decision. A preference for prenatal testing decisions to reflect an informed choice was predicted by (i) country and (ii) the perceived importance of significant others’ views. Education, age and gender did not predict decisions.

Conclusion The implications of these findings for policy and practice depend upon whether placing a low value on parental choice, but a high value on the others’ views regarding prenatal testing is considered an informed choice. Further research is needed to determine whether cultural variation in values remains significant in a multicultural society.
Correlation between the dioptric power, astigmatism and surface shape of the anterior and posterior corneal surfaces
Authors: Mas David , Espinosa Julian , Domenech Begoña , Perez Jorge , Kasprzak Henryk , Illueca Carlos
Published: April 2009

A knowledge of the shape of the cornea is of major importance for the planning and monitoring of surgery, and for the correct diagnosis of corneal diseases. Many authors have studied the geometry of the second corneal surface in the central region and it has been stated that there is a high correlation between the central radii of curvature and asphericities of the two corneal surfaces. In this work we extend this study to a larger, central, 6 mm diameter of the cornea. Surface height data, obtained with an Oculus Pentacam from 42 eyes of 21 subjects, were analysed to yield surface power vectors. Corneal heights of both surfaces were also decomposed into low‐order Zernike polynomials and the correlations between each of the power vectors and low‐order Zernike coefficients for the two surfaces were studied. There was not only a strong correlation between spherical powers and Zernike defocus coefficients, but also between the astigmatic components. The correspondence between the astigmatism in both surfaces found here can be of the utmost importance in planning optical surgery, since perfect spherical ablation of the first surface does not assure total correction of corneal astigmatism.
Straylight in the human eye: testing objectivity and optical character of the psychophysical measurement
Authors: Van Den Berg Thomas J. T. P. , Franssen Luuk , Coppens Joris E.
Published: April 2009

The point spread function or PSF of the human eye encompasses hugely different domains: a small‐angle, high‐intensity domain, called the ‘PSF core’, and a large‐angle, low‐intensity domain, usually referred to as ‘straylight’. The first domain can be assessed by available double‐pass or other optical techniques. For the second domain psychophysical techniques have been developed, in particular the Compensation Comparison or CC technique, recently made available for clinical application in the C‐Quant instrument. We address the question of whether the psychophysical technique gives measures of straylight that are compatible with those made by optical methods. With a small adaptation the CC method can be used to assess straylight from physical light scattering samples, instead of straylight in the eye, using the same psychophysics, but without interference from the ocular straylight. The light scattered by each of seven light‐scattering samples, encompassing the range of straylight values observed in human eyes, was measured by two optical methods and by the psychophysical technique. The results showed that the optical and psychophysical measurements for the seven samples were almost identical.
Depolarization properties of the optic nerve head: the effect of age
Authors: Bueno Juan M. , Cookson Christopher J. , Hunter Jennifer J. , Kisilak Marsha L. , Campbell Melanie C. W.
Published: April 2009

The degree of polarization (DOP) of the light reflected from the optic nerve head has been assessed by means of a polarimetric scanning laser ophthalmoscope as a function of the age of the participants. Four fundus images corresponding to independent polarization states in the recording pathway were used to compute the spatially‐resolved DOP. This was not uniform across the optic nerve head and depended on both the location and the participant’s age. Along a peripapillary annulus the DOP followed a double‐peak pattern. Moreover, the values along this annulus decreased significantly with increasing age. This depolarization appears to originate in part in the retinal nerve fiber layer. Detailed age‐dependent knowledge of the ocular depolarization properties may help to improve clinical diagnosis of the retinal nerve fiber layer.
Customized hydrogel contact lenses for keratoconus incorporating correction for vertical coma aberration
Authors: Katsoulos Costas , Karageorgiadis Lefteris , Vasileiou Nikos , Mousafeiropoulos Theodore , Asimellis George
Published: April 2009

Purpose:  To study the effects on visual performance of a novel custom hydrogel contact lens, which employs a correction for vertical coma aberration, in keratoconic eyes.

Methods:  Six subjects (8 eyes) with mild or moderate keratoconus were recruited for the study. Preliminary measurements included corneal topography, wavefront aberrometry, subjective refraction, visual acuity (VA) and 50% contrast VA. Based on the aberrometry data, customized lenses were made and fitted to the subjects. Evaluation of the on‐eye performance of the lenses was carried out, including wavefront aberrometry, over‐refraction, VA and 50% contrast VA. In two of the subjects, both eyes were fitted with the customized lenses, and binocular performance was evaluated.

Results:  Monocular visual performance with a 4 mm pupil, with the lenses worn, was improved, and reached the mean values of −0.003 (LogMar units) of 100% high contrast VA, and 0.049 (in LogMar units) of 50% contrast VA. Vertical coma aberration and total higher‐order aberrations (HOAs) were reduced (naked eyes: −0.64 ± 0.21 root mean square (rms) of vertical coma and 0.86 ± 0.15 rms of total HOAs; with the lenses worn: −0.29 ± 0.23 rms of vertical coma and 0.57 ± 0.17 rms of total HOAs, all for a 4 mm pupil). Binocular VA results from two of the subjects were on average −0.040 (LogMar units) 100% high contrast acuity and −0.060 (LogMar units) 50% contrast visual acuity.

Conclusions:  Customized hydrogel contact lenses implementing correction of vertical coma, have been found to improve both monocular and binocular visual performance of eyes affected with mild or moderate keratoconus.
Narrow angle light scatter in rabbit corneas after excimer laser surface ablation
Authors: Ginis Harilaos , Pentari Iro , De Brouwere Dirk , Bouzoukis Dimitris , Naoumidi Irini , Pallikaris Ioannis
Published: April 2009

Corneal haze following excimer laser ablation is an adverse after‐effect of photorefractive keratectomy (PRK) and is associated with the development of subepithelial opacities. The present work pertains to the measurement of light scattering in rabbit corneas following excimer laser treatment; to the microscopic analysis of the light‐scattering corneal structures; and to the development of a mathematical model of light propagation through the post‐laser treatment cornea. Photorefractive keratectomy (PRK‐6D, 6 mm optical zone) followed by standard postoperative pharmaceutical treatment was performed on rabbit eyes. Animals were examined clinically on a weekly basis and sacrificed after the tenth postoperative week. Confocal microscope image sequences were acquired immediately before animal sacrifice. After the scatter measurement, the corneas were prepared for histopathological evaluation. The subepithelial structures observed using the confocal microscope correspond to refractive index (and therefore optical path difference (OPD) variation. This OPD distribution can be approximated with a fractal surface, band‐pass filtered in the Fourier domain. The angular distribution of scattered light is characterised by a narrow forward peak of the order of 0.5° full‐width at half maximum (FWHM) in accordance with the sizes of the subepithelial structures (5–150 μm).The intensity of scattered light is correlated with the thickness of the subepithelial scar‐tissue layer.
Numerical analysis of interferograms for evaluation of tear film build‐up time
Authors: Szczesna Dorota H. , Kasprzak Henryk T.
Published: April 2009

The lateral shearing interferometer was applied to thein vivodynamic investigation of the external surface of the pre‐corneal tear film after an eye blink. Sequences of interferograms were recorded at a sampling frequency of 25 Hz. Immediately after every eye blink, a bright pattern was observed under the interference fringes. This disappeared after a short time interval (around 0.5–2 s): smooth interference fringes were then observed, corresponding to the creation of a smooth anterior optical surface over the cornea. The purpose of this study is to describe in detail the kinetics of pre‐corneal tear film stability and to propose quantitative measures of the stabilisation process in healthy eyes during the 3 s period after a blink. Two methods of quantitative assessment of the tear film build‐up time are presented. The first is based upon the evaluation of the inhomogeneity of the background of the interferogram; the second evaluates the orientation of the structure of the background by the analysis of the zero order of the Fast Fourier Transform (FFT) spectrum. The quasi‐vertically oriented bright line patterns observed in interferograms immediately after a blink and the mirror‐symmetry of their tilts for right and left eyes indicate that the pattern is related to the wiping movements of the upper eyelids during the eye blink.
Temporal dynamics of ocular aberrations: monocular vs binocular vision
Authors: Mira‐Agudelo A. , Lundström L. , Artal P.
Published: April 2009

The temporal dynamics of ocular aberrations are important for the evaluation of, e.g. the accuracy of aberration estimates, the correlation to visual performance, and the requirements for real‐time correction with adaptive optics. Traditionally, studies on the eye’s dynamic behavior have been performed monocularly, which might have affected the results. In this study we measured aberrations and their temporal dynamics both monocularly and binocularly in the relaxed and accommodated state for six healthy subjects. Temporal frequencies up to 100 Hz were measured with a fast‐acquisition Hartmann–Shack wavefront sensor having an open field‐of‐view configuration which allowed fixation to real targets. Wavefront aberrations were collected in temporal series of 5 s duration during binocular and monocular vision with fixation targets at 5 m and 25 cm distance. As expected, a larger temporal variability was found in the root‐mean‐square wavefront error when the eye accommodated, mainly for frequencies lower than 30 Hz. A statistically‐significant difference in temporal behavior between monocular and binocular viewing conditions was found. However, on average it was too small to be of practical importance, although some subjects showed a notably higher variability for the monocular case during near vision. We did find differences in pupil size with mono‐ and binocular vision but the pupil size temporal dynamics did not behave in the same way as the aberrations’ dynamics.