Essays on Personnel Economics and Gender Issues

This thesis consists of four self-contained essays in economics. Tournaments and unfair treatment. This paper introduces the negative feelings associated with the perception of being unfairly treated into a tournament model and examines the impact of these perceptions on workers’ efforts and their willingness to work overtime. The effect of unfair treatment on workers’ behavior is ambiguous in the model in that two countervailing effects arise: a negative impulsive effect and a positive strategic effect. The impulsive effect implies that workers react to the perception of being unfairly treated by reducing their level of effort. The strategic effect implies that workers raise this level in order to improve their career opportunities and thereby avoid feeling even more unfairly treated in the future. An empirical test of the model using survey data from a Swedish municipal utility shows that the overall effect is negative. This suggests that employers should consider the negative impulsive effect of unfair treatment on effort and overtime in designing contracts and determining on promotions. Late careers in Sweden between 1970 and 2000. In this essay Swedish workers’ late careers between 1970 and 2000 are studied. The aim is to examine older workers’ career patterns and whether they have changed during this period. For example, is there a difference in career mobility or labor market exiting between cohorts? What affects the late career, and does this differ between cohorts? The analysis shows that between 1970 and 2000 the late careers of Swedish workers comprised of few job changes and consisted more of “trying to keep the job you had in your mid-fifties” than of climbing up the promotion ladder. There are no cohort differences in this pattern. Also a large fraction of the older workers exited the labor market before the normal retirement age of 65. During the 1970s and first part of the 1980s, 56 percent of the older workers made an early exit and the average drop-out age was 63. During the late 1980s and the 1990s the share of old workers who made an early exit had risen to 76 percent and the average drop-out age had dropped to 61.5. Different factors have affected the probabilities of an early exit between 1970 and 2000. For example, skills did affect the risk of exiting the labor market during the 1970s and up to the mid-1980s, but not in the late 1980s or the 1990s. During the first period old workers in the lowest occupations or with the lowest level of education were more likely to exit the labor market than more highly skilled workers. In the second period old workers at all levels of skill had the same probability of leaving the labor market. The growth and survival of establishments: does gender segregation matter? We empirically examine the employment dynamics that arise in Becker’s (1957) model of labor market discrimination. According to the model, firms that employ a large fraction of women will be relatively more profitable due to lower wage costs, and thus enjoy a greater probability of surviving and growing by underselling other firms in the competitive product market. In order to test these implications, we use a unique Swedish matched employer-employee data set. We find that female-dominated establishments do not enjoy any greater probability of surviving and do not grow faster than other establishments. Additionally, we find that integrated establishments, in terms of gender, age and education levels, are more successful than other establishments. Thus, attempts by legislators to integrate firms along all dimensions of diversity may have positive effects on the growth and survival of firms. Risk and overconfidence – Gender differences in financial decision-making as revealed in the TV game-show Jeopardy. We have used unique data from the Swedish version of the TV-show Jeopardy to uncover gender differences in financial decision-making by looking at the contestants’ final wagering strategies. After ruling out empirical best-responses, which do appear in Jeopardy in the US, a simple model is derived to show that risk preferences, the subjective and objective probabilities of answering correctly (individual and group competence), determine wagering strategies. The empirical model shows that, on average, women adopt more conservative and diversified strategies, while men’s strategies aim for the greatest gains. Further, women’s strategies are more responsive to the competence measures, which suggests that they are less overconfident. Together these traits make women more successful players. These results are in line with earlier findings on gender and financial trading.

Ni una más. International cooperation against gender-based discrimination: the femicide case in Ciudad Juárez, Chihuahua, Mexico

The femicide in Ciudad Juárez is a story made of extreme violence against women for different reasons, by different actors, under different circumstances, and following different behavioural patterns. All within a gender discrimination frame based on the idea that women are inferior, interchangeable and disposable according to the patriarchal hierarchy still present in Mexico, but strongly reinforced by a sort of conspiracy of silence provoked either by the high impunity rate, the governmental incompetence to solve the crimes, or the general indifference of the population. It is the story of hundreds of kidnapped, raped, in many cases tortured, and murdered young women in the border between Mexico and the United States. The murders first came into light in 1993 and up to now young women continue to “disappear” without any hope of bringing the perpetrators to justice, stopping impunity, convicting the assassins, and bringing justice to the families of the deceased girls and women. The main questions about femicide in Ciudad Juárez seem to be: why were they brutally assassinated?, why most of the crimes have not been solved yet?, why and how is Ciudad Juárez different from other border cities with the same characteristics?, which powers are behind those crimes in a city that implies mainly women as its labor force, and which has the lowest unemployment rate in the whole country? But there are also many other questions dealing more with the context, the Juarences’ lifestyles, the eventual hidden powers behind the crimes, the possible murderers’ reasons, the response of the local civil society, or the international community actions to fight against femicide there, among many other things, that are still waiting for an answer and that this paper will ‘narrate’ in order to provide a holistic panorama for the readers. But above all there is the need to remember that every single woman or girl assassinated there had a name, an identity, a family, a story to be told time after time and as many times as necessary, in order to avoid accepting these crimes just as statistics, as cold numbers that might make us forget the human tragedy that has been flagellating the city since 1993. We must remember as well that their deaths express gender oppression, the inequality of the relations between what is male and what is female, a manifestation of domination, terror, social extermination, patriarchal hegemony, social class and impunity. The city is the perfect mirror where all the contradictions of globalization get reflected. It is there where all the globalization evils are present and survive by sucking their women’s blood. It is a city where some concepts such as gender, migration and power are closely related with a negative connotation.

Evolutionary methods for self-organizing cooperation in peer-to-peer networks

The Peer-to-Peer network paradigm is drawing the attention of both final users and researchers for its features. P2P networks shift from the classic client-server approach to a high level of decentralization where there is no central control and all the nodes should be able not only to require services, but to provide them to other peers as well. While on one hand such high level of decentralization might lead to interesting properties like scalability and fault tolerance, on the other hand it implies many new problems to deal with. A key feature of many P2P systems is openness, meaning that everybody is potentially able to join a network with no need for subscription or payment systems. The combination of openness and lack of central control makes it feasible for a user to free-ride, that is to increase its own benefit by using services without allocating resources to satisfy other peers’ requests. One of the main goals when designing a P2P system is therefore to achieve cooperation between users. Given the nature of P2P systems based on simple local interactions of many peers having partial knowledge of the whole system, an interesting way to achieve desired properties on a system scale might consist in obtaining them as emergent properties of the many interactions occurring at local node level. Two methods are typically used to face the problem of cooperation in P2P networks: 1) engineering emergent properties when designing the protocol; 2) study the system as a game and apply Game Theory techniques, especially to find Nash Equilibria in the game and to reach them making the system stable against possible deviant behaviors. In this work we present an evolutionary framework to enforce cooperative behaviour in P2P networks that is alternative to both the methods mentioned above. Our approach is based on an evolutionary algorithm inspired by computational sociology and evolutionary game theory, consisting in having each peer periodically trying to copy another peer which is performing better. The proposed algorithms, called SLAC and SLACER, draw inspiration from tag systems originated in computational sociology, the main idea behind the algorithm consists in having low performance nodes copying high performance ones. The algorithm is run locally by every node and leads to an evolution of the network both from the topology and from the nodes’ strategy point of view. Initial tests with a simple Prisoners’ Dilemma application show how SLAC is able to bring the network to a state of high cooperation independently from the initial network conditions. Interesting results are obtained when studying the effect of cheating nodes on SLAC algorithm. In fact in some cases selfish nodes rationally exploiting the system for their own benefit can actually improve system performance from the cooperation formation point of view. The final step is to apply our results to more realistic scenarios. We put our efforts in studying and improving the BitTorrent protocol. BitTorrent was chosen not only for its popularity but because it has many points in common with SLAC and SLACER algorithms, ranging from the game theoretical inspiration (tit-for-tat-like mechanism) to the swarms topology. We discovered fairness, meant as ratio between uploaded and downloaded data, to be a weakness of the original BitTorrent protocol and we drew inspiration from the knowledge of cooperation formation and maintenance mechanism derived from the development and analysis of SLAC and SLACER, to improve fairness and tackle freeriding and cheating in BitTorrent. We produced an extension of BitTorrent called BitFair that has been evaluated through simulation and has shown the abilities of enforcing fairness and tackling free-riding and cheating nodes.

Three-dimensional CT reconstruction: other tool to teach in the veterinary colleges

[ES]The purpose of this paper was to use threedimensional computed tomographic reconstruction as another tool to teach in the veterinary colleges. 2-millimeters thick transverse images of two foals and one dog were obtained. Images provided excellent detail of relevant anatomic structures and detailed information regarding the extent of disease and accurate discrimination of neoplastic versus non-neoplastic diseases. Tridimensional reconstruction can be a valuable diagnostic aid for clinical evaluation of several disturbances and could be used as a tool for teaching anatomy in veterinary schools.

Nanostructuring by templated synthesis of nanowires and controlled crystallization of calcium phosphate on self-assembled monolayers

The idea was to obtain nanowires in a chemical laboratory under convenient and simple conditions by employing templates. Thus it was possible to produce nanochains by interlinking of gold colloids synthesized by the two-phase-method of M. Brust with by making use of vanadiumoxide nanotubes as template. The length of the resulting nanowires is varying between 1100 nm and 200 nm with a diameter of about 16 nm. Due to a flexible linker the obtained nanowires are not completely rigid. These unique structural features could make them interesting objects for structuring and assembling in the nanoscale range. Another way to produce gold nanowires was realized by a two-step surface metallization procedure, using type I collagen fibres as a template. Gold colloids were used to label the collagen fibres by direct electrostatic interaction, followed by growth steps to enhance the size of the adsorbed colloidal gold crystals, resulting in a complete metallization of the template surface. The length of the resulting gold nanowires reaches several micrometers, with a diameter ~ 100 to 120 nm. To gain a deeper insight into the process of biomineralization the cooperative effect of self-assembled monolayers as substrate and a soluble counterpart on the nucleation and crystal growth of calcium phosphate was studied by diffusion techniques with a pH switch as initiator. As soluble component Perlucin and Nacrein were used. Both are proteins originally extracted from marine organisms, the first one from the Abalone shell and the second one from oyster pearls. Both are supposed to facilitate the calcium carbonate formation in vivo. Studies with Perlucin revealed that this protein shows a clear cooperative effect at a very low concentration with a hydrophobic surface promoting the calcium phosphate precipitation resulting in a sponge like structure of hydroxyapatite. The Perlucin molecule is very flexible and is unfolded by adsorbing to the hydrophobic surface and uncovers its active side. Hydrophilic surfaces did not have a deeper impact. Studies with Nacrein as additive have shown that the protein stabilizes octacalcium phosphate at room temperature on carboxylic self-assembled monolayer and at 34 °C on all other employed surfaces by interaction with the mineral. On the hydroxyl-, alkyl-, and amin-terminated self-assembled monolayers at room temperature the octacalcium phosphate get transformed to hydroxyapatite. Main analytical techniques which are used in this work are transmission electron microscopy, high resolution scanning electron microscopy, surface plasmon resonance spectroscopy, atomic force microscopy, Raman micro-spectroscopy and quartz crystal microbalance.

Electrostatically self-assembled nanoparticles based on biomolecules

In this work, two different systems were investigated to develop fundamental understanding of the self-assembly behavior of polyelectrolytes and small organic counterions with a certain geometry. Complexes formed were characterized by light scattering in solution, as well as UV-Vis spectroscopy, analytical ultracentrifugation, gel electrophoresis, zeta potential and IR spectroscopy. The morphologies of the aggregates were observed by AFM in dried state on surface. The charge ratio, the valence and the structure of the counterion were shown to represent key parameters in the complexation. The influence of polyelectrolyte type and molecular weights was also determined for the structure formed.rnrnOne system was mainly focused on the association of double-strand DNA with non-intercalating divalent and tetravalent organic counterions. The other model system involved linear NaPSS and oligolysines. In addition, various influences on the morphology of the charged self-assembly complexes in AFM studies were discussed. It was shown that electrostatic self-assembly of DNA and non-intercalating counterions as well as of a linear synthetic polyelectrolyte with oligolysine counterions that can build mutual hydrogen bonds can yield supramolecular aggregates of a defined size. Various morphologies (flower-like, rod-like, toroidal and spherical) of the assemblies were obtained for different combinations of polyelectrolyte and counterions. Results presented in this work are of importance for the fundamental understanding of the association behavior of various polyelectrolytes and organic counterions. The selection of biopolymers for the study may give an opportunity to transfer the basic research results into biological applications, such as gene therapy or drug delivery.rn

Who can (not) be Greek? Citizenship, Identity and Belonging among youth of sub-Saharan African background in Athens

‘Who can be Greek?’ This was the question posed to the Greek society for the first time before the implementation of the Act 3838 in March 2010 which gave the right to access the Greek citizenship -under specific preconditions- to all children of legal migrants born or schooled in Greece. This change of the Nationality Code in order to include all those children was coincided by the economic crisis resulting into the rise of xenophobia, racism and extreme-right rhetoric. The outcome was the cancellation of the Act 3838 by the State Council in February 2013. Under this particular framework, the notions of identity and belonging formed among the youth of African background in Athens are explored. The ways those youngsters perceive not only themselves but also their peers, their countries of origin and the country they live in, are crucial elements of their self-identification. Researches have shown that the integration of the second generation is highly connected to their legal and social status. However, integration is a rather complex process, influenced and shaped by many variables and multiple factors. It is not linear; therefore, its outcomes are difficult to be predicted. Yet, I argue that citizenship acquisition facilitates the process as it transforms those children from ‘aliens’ to ‘citizens’. How these youngsters are perceived by the majority society and the State is one of the core questions of the research, focusing on the imposed dual ‘otherness’ they are subject to. On the one hand, they have to deal with the ‘otherness’ originating from the migrant status inherited to them by their parents, and on the other with the ‘otherness’ deriving from their different phenotypic characteristics. Race matters and becomes a means of discrimination against youth of African background who are perceived as inassimilable and ‘forever others’.

A biomimetic model membrane system on oxidic surfaces designed for the investigation of cytochrome c oxidase and other membrane proteins by fluorescence and waveguide spectroscopy

Die transmembrane Potenzialdifferenz Δφm ist direkt mit der katalytischen Aktivität der Cytochrom c Oxidase (CcO) verknüpft. Die CcO ist das terminale Enzym (Komplex IV) in der Atmungskette der Mitochondrien. Das Enzym katalysiert die Reduktion von O2 zu 2 H2O. Dabei werden Elektronen vom natürlichen Substrat Cytochrom c zur CcO übertragen. Der Eleltronentransfer innerhalb der CcO ist an die Protonentranslokation über die Membran gekoppelt. Folglich bildet sich über der inneren Membrane der Mitochondrien eine Differenz in der Protonenkonzentration. Zusätzlich wird eine Potenzialdifferenz Δφm generiert.rnrnDas Transmembranpotenzial Δφm kann mit Hilfe der Fluoreszenzspektroskopie unter Einsatz eines potenzialemfindlichen Farbstoffs gemessen werden. Um quantitative Aussagen aus solchen Untersuchungen ableiten zu können, müssen zuvor Kalibrierungsmessungen am Membransystem durchgeführt werden.rnrnIn dieser Arbeit werden Kalibrierungsmessungen von Δφm in einer Modellmembrane mit inkorporiertem CcO vorgestellt. Dazu wurde ein biomimetisches Membransystem, die Proteinverankerte Doppelschicht (protein-tethered Bilayer Lipid Membrane, ptBLM), auf einem transparenten, leitfähigem Substrat (Indiumzinnoxid, ITO) entwickelt. ITO ermöglicht den simultanen Einsatz von elektrochemischen und Fluoreszenz- oder optischen wellenleiterspektroskopischen Methoden. Das Δφm in der ptBLM wurde durch extern angelegte, definierte elektrische Spannungen induziert. rnrnEine dünne Hydrogelschicht wurde als "soft cushion" für die ptBLM auf ITO eingesetzt. Das Polymernetzwerk enthält die NTA Funktionsgruppen zur orientierten Immobilisierung der CcO auf der Oberfläche der Hydrogels mit Hilfe der Ni-NTA Technik. Die ptBLM wurde nach der Immobilisierung der CcO mittels in-situ Dialyse gebildet. Elektrochemische Impedanzmessungen zeigten einen hohen elektrischen Widerstand (≈ 1 MΩ) der ptBLM. Optische Wellenleiterspektren (SPR / OWS) zeigten eine erhöhte Anisotropie des Systems nach der Bildung der Doppellipidschicht. Cyklovoltammetriemessungen von reduziertem Cytochrom c bestätigten die Aktivität der CcO in der Hydrogel-gestützten ptBLM. Das Membranpotenzial in der Hydrogel-gestützten ptBLM, induziert durch definierte elektrische Spannungen, wurde mit Hilfe der ratiometrischen Fluoreszenzspektroskopie gemessen. Referenzmessungen mit einer einfach verankerten Dopplellipidschicht (tBLM) lieferten einen Umrechnungsfaktor zwischen dem ratiometrischen Parameter Rn und dem Membranpotenzial (0,05 / 100 mV). Die Nachweisgrenze für das Membranpotenzial in einer Hydrogel-gestützten ptBLM lag bei ≈ 80 mV. Diese Daten dienen als gute Grundlage für künftige Untersuchungen des selbstgenerierten Δφm der CcO in einer ptBLM.

Lipophilic nucleosides: studies toward self-assembled functional materials

Molecular self-assembly takes advantage of supramolecular non-covalent interactions (ionic, hydrophobic, van der Waals, hydrogen and coordination bonds) for the construction of organized and tunable systems. In this field, lipophilic guanosines can represent powerful building blocks thanks to their aggregation proprieties in organic solvents, which can be controlled by addition or removal of cations. For example, potassium ion can template the formation of piled G-quartets structures, while in its absence ribbon-like G aggregates are generated in solution. In this thesis we explored the possibility of using guanosines as scaffolds to direct the construction of ordered and self-assembled architectures, one of the main goals of bottom-up approach in nanotechnology. In Chapter III we will describe Langmuir-Blodgett films obtained from guanosines and other lipophilic nucleosides, revealing the “special” behavior of guanine in comparison with the other nucleobases. In Chapter IV we will report the synthesis of several thiophene-functionalized guanosines and the studies towards their possible use in organic electronics: the pre-programmed organization of terthiophene residues in ribbon aggregates could allow charge conduction through π-π stacked oligothiophene functionalities. The construction and the behavior of some simple electronic nanodevices based on these organized thiopehene-guanosine hybrids has been explored.

Push-out bond strength of CAD/CAM-ceramic luted to dentin with self-adhesive resin cements

OBJECTIVES: This study evaluated the initial and the artificially aged push-out bond strength between ceramic and dentin produced by one of five resin cements. METHODS: Two-hundred direct ceramic restorations (IPS Empress CAD) were luted to standardized Class I cavities in extracted human molars using one of four self-adhesive cements (SpeedCEM, RelyX Unicem Aplicap, SmartCem2 and iCEM) or a reference etch-and-rinse resin cement (Syntac/Variolink II) (n=40/cement). Push-out bond strength (PBS) was measured (1) after 24h water storage (non-aged group; n=20/cement) or (2) after artificial ageing with 5000 thermal cycles followed by 6 months humid storage (aged group; n=20/cement). Nonparametrical ANOVA and pairwise Wilcoxon rank-sum tests with Bonferroni-Holm adjustment were applied for statistical analysis. The significance level was set at alpha=0.05. In addition, failure mode and fracture pattern were analyzed by stereomicroscope and scanning electron microscopy. RESULTS: Whereas no statistically significant effect of storage condition was found (p=0.441), there was a significant effect of resin cement (p<0.0001): RelyX Unicem showed significantly higher PBS than the other cements. Syntac/Variolink II showed significantly higher PBS than SmartCEM2 (p<0.001). No significant differences were found between SpeedCEM, SmartCem2, and iCEM. The predominant failure mode was adhesive failure of cements at the dentin interface except for RelyX Unicem which in most cases showed cohesive failure in ceramic. SIGNIFICANCE: The resin cements showed marked differences in push-out bond strength when used for luting ceramic restorations to dentin. Variolink II with the etch-and-rinse adhesive Syntac did not perform better than three of the four self-adhesive resin cements tested.

Immunomodulatory therapy to achieve maximum efficacy: doses, monitoring, compliance, and self-infusion at home

The Oxford Programme for Immunomodulatory Immunoglobulin Therapy has been operating since 1992 at Oxford Radcliffe Hospitals in the UK. Initially, this program was set up for patients with multifocal motor neuropathy or chronic inflammatory demyelinating poly-neuropathy to receive reduced doses of intravenous immunoglobulin (IVIG) in clinic on a regular basis (usually every 3 weeks). The program then rapidly expanded to include self-infusion at home, which monitoring showed to be safe and effective. It has been since extended to the treatment of other autoimmune diseases in which IVIG has been shown to be efficacious.

The relationship between self-efficacy and resting blood pressure in spousal Alzheimer's caregivers

Objective. To examine whether high levels of self-efficacy for problem-focused coping were significantly related to several resting BP measures in spousal Alzheimer's disease caregivers. Design. Cross-sectional. Methods. Participants included 100 older caregivers (mean age = 73.8 ± 8.14 years) providing in home care for a spouse with Alzheimer's disease. All participants completed a 13-item short form of the Coping Self-Efficacy Scale and underwent an in-home assessment where a visiting nurse took the average of three serial BP readings. Multiple regression was used to examine the relationship between self-efficacy and mean arterial pressure (MAP), systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) after controlling for age, gender, smoking history, body mass index, the care recipient's clinical dementia rating, diabetes, alcohol use, and the use of antihypertensive medications. Results. Overall, high levels of self-efficacy for problem-focused coping were associated with lower MAP, SBP, and PP. Self-efficacy for problem-focused coping was marginally associated with resting DBP, but not significant. In addition, we conducted secondary analyses of the other two self-efficacy scales to explore the relationship between each dimension and MAP. We found that there were no significant relationships found between MAP and self-efficacy for stopping unpleasant thoughts/emotions or self-efficacy for getting social support. Conclusions. The present study adds to the current body of literature by illustrating the possibility that higher self-efficacy can have physiological advantages, perhaps by buffering chronic stress's impact on resting BP. Another contribution of the current study is its attempt to understand the role of each individual component of self-efficacy. These findings invite future research to investigate whether caregivers might experience cardiovascular benefits from interventions aimed at enhancing self-efficacy.

The Effects of Self-Esteem and Expectancies for Success on Affective Reactions to Achievement

Affective reactions to academic performance appear to be influenced by performance outcome, self-esteem, and causal attributions. We investigated whether expectancies for success and the confirmation or disconfirmation of epectancies also influenced students' affective reactions and causal attributions in achievement settings. Subjects were 132 university students. Causal attributions and affective reactions to an achievement-related situation were assessed and related to students' self-esteem, expectancies for success, and confirmation or disconfirmation of expectancies. Results indicated that causal attributions were related to confirmation or disconfirmation of expectancies for success and to self-esteem. Affective reactions were related to the interaction of self-esteem, expectancies for success, and confirmation or disconfirmation of expectancies. Further analysis suggested that students' affective reactions to performance may serve to maintain existing levels of self-esteem. The role of self-referent and other-referent emotions in self-esteem maintenance was also discussed.

Duration discrimination in a series of rhythmic events

Duration discrimination of the last of a series of four clicks was investigated. Examination of psychophysical functions from eight subjects revealed evidence for a Weber’s law model relating discrimination to base interclick interval. Also, the point of subjective equality was seen to change reliably as a function of base rate.