This study was conducted to ascertain the impacts of bed leveling, following ship channel dredging operations, and to also investigate the hydrodynamic flow field around box bed levelers. Laboratory experiments were conducted with bed levelers operating in the laboratory using video cameras for flow visualization. Computer software and numerical codes, called FANS, were used to validate the laboratory experiments. The study was split into two major parts: laboratory experiments and hydrodynamic modeling. The laboratory experiment was conducted to model how bed levelers interact with the ship channel bottom after hopper dredge dragheads (blades) made passes and created uneven trenches. These interactions were observed using both underwater and hand-held cameras. The hydrodynamic modeling was accomplished using GRIDGEN and PEGSUS commercial software for generating grid and input data files in the pre-processing phase, Finite-Analytic Navier-Stokes (FANS) software for simulation in the processing phase, and two commercial software (Fieldview and Tecplot) for plotting the images and graphs in the post-processing phase. An interesting phenomenon was observed in the laboratory experimental runs. The flow field showed reversed flow in front of the moving bed leveler and the trench parallel to the direction of the bed leveler. The flow in the parallel trench was observed to be in the same direction as the bed leveler movement, and it was expected that the flow would travel under the bed leveler. The bed leveler was towed at two specified constant speeds: 0.25 m/s (0.82 ft/s) and 0.5 m/s (1.64 ft/s) and at a water depth of 1.22 m (4.00 ft) Similarly, the images and plots of the hydrodynamic modeling obtained from FieldView and Tecplot software showed flow reversal, depicted by the negative velocities, within the vicinity of the trench, as the model bed leveler moved past and interacted with the fluid. The negative velocity had a magnitude close to 0.5 m/s (1.64 ft/s), which was the velocity used in running the laboratory experiments. The hydrodynamic simulation matched closely with the experimental observations, and thus, the laboratory observation was confirmed. The final results obtained from the numerical modeling helped to understand the hydrodynamic effects around the box bed leveler.

This dissertation is composed of two essays that relate topics in the fields of labor economics, migration, experimental economics and entrepreneurship, taking into account a gender perspective. The first essay examines collective remittances, those sent by migrants' associations to be invested in community projects in their hometowns, matched by governmental funds through the Mexican program 3x1 Para Migrantes. This study evaluates the effect of collective remittances on the probability of wanting to migrate, being employed and in the labor force, and on the amount of hours worked of adult men and women in 2002 and 2005 in Mexico. Collective remittances have a positive, albeit modest, impact on the employment and labor force participation of adults in participant municipalities, but no effect on the preferences to migrate. Important differences are observed by type of project executed and by gender and age cohort, with younger men and women benefiting the most from investments in schools and sports facilities. The second essay conducts a series of laboratory experiments to test the hypothesis that, while stress worsens entrepreneurial choices and outcomes for all, it does so more for women than men. Results show that the effects of stress on choice and performance are more negative for women. Experimentally-induced stress causes more long-lasting productivity losses for women, and additional losses for making choices that do not maximize income given one's productivity. The negative treatment effect on women's productivity, choice quality, and earnings is driven by women who experienced negative life events. The mechanisms that affect choices also differ by gender. Men are more likely to present inconsistencies during a series of entrepreneurial decisions, and women to have inaccurate beliefs about their performance.

What do we do when we realise that others with whom we interact already know something about relevant qualities of ours? Do we relying on the information that we naturally emit to get our message across, or do we take actions to try to change the situation in our favour? And, does the information that we emit, generated intentionally or unintentionally, allow us to cooperate with others and conflict to be resolved peacefully? Drawing on signalling and 'countersignalling' theories, and a recent behavioural theory, I explore these questions using two experiments in which the relevant qualities are trustworthiness and toughness, and observational data from the 1997 Survey of Inmates in State and Federal Correctional Facilities concerning violence among prisoners. In the experiments, subjects, who do not know what will follow, initially create a natural indicator of their qualities, and subsequently, have the opportunity to send another indicator, this time fully informed. In one experiment, consistent with countersignalling theory, subjects whose generosity is clear deign to send further information, while those whose generosity can be called under question choose to update their initial action the most. In the other, the toughest subjects put the most effort into getting their message across. Consistent among both, senders' actions correspond to receivers' evaluations. Finally, I find that pertinent information can allow conflicts to be resolved successfully; it is linked with less violence in prison and in a laboratory-based contest.

No description available.

No description available.

Foram estudados cinco casos históricos de escorregamentos ocorridos na cidade de Salvador - Bahia, através do levantamento e tratamento dos dados preexistentes. Também foram realizados ensaios complementares através da instrumentação em campo com tensiômetros e ensaios de laboratório. A retroanálise, objetivo central desse trabalho foi realizada a partir das geometrias de cada uma das encostas, antes e após a ruptura resultando na definição dos possíveis parâmetros médios de resistência ao cisalhamento. Secundariamente foram realizadas análises de estabilidade convencional para a avaliação dos fatores de segurança de cada encosta, com os parâmetros de resistência na condição não saturada e saturada. Por fim foram efetuadas simulações numéricas que visavam reproduzir as condições que levaram à ruptura da encosta do Alto do Bom Viver, baseado nos conceitos da mecânica dos solos não saturados. Os resultados mostram que a maioria dos escorregamentos estudados, ocorre no horizonte do solo residual maduro, onde o valor de ângulo de atrito médio é 34º, condizente com as superfícies de rupturas pouco profundas observadas em campo. As análises paramétricas sugerem que o mecanismo de ruptura mais provável esteja relacionado à diminuição da coesão aparente do solo em virtude da diminuição da sucção. / Five historical cases of landslides in the city of Salvador, Bahia, were studied through the survey and treatment of the preexistent data. Complementary experiments were accomplished through the instrumentation field using tensiometers and laboratory testing. The back-analysis, main objective of this research, was accomplished through the geometries of each slope, before and after the rupture, resulting in the definition of the possible medium parameters of resistance to shear. Secondary, analysis of the conventional stability to the evaluation of safety factors of each slope was accomplished, with the parameters of resistance in the unsaturated and saturated condition. At last, numerical simulations were done, aiming at reproducing the conditions which led to the rupture of the slope of Alto do Bom Viver, based on the concepts of mechanics of non saturated soil. The results demonstrated that the majority of the slips studied occur in the horizon of the mature residual soil, where the value of the angle of the medium attrition is of 34 degrees, suitable with the surface of little deep ruptures observed in the field. The parametric analysis suggests that the most probable mechanism of rupture is related to the decrease of the apparent cohesion of the soil due to the decrease of suction.

<p>Sammanfattning</p><p>Laborationer i naturvetenskapliga ämnen är en naturlig del av undervisningen. Syftet med den här uppsatsen är att ta reda på om man tar bort en möjlighet till inlärning och förståelse för eleverna om laborationer inte används i undervisningen. Vidare ville jag undersöka om lärare och elever anser att laborationer utvecklar förståelsen av naturvetenskap, dessutom om eleverna förstår syftena med laborationerna.</p><p>Undersökningen utfördes genom att kvalitativa intervjuer gjordes med fyra lärare och sex elever i en gymnasieskola. Resultatet visar att lärarna har olika åsikter om laborationens betydelse för förståelsen av ämnet. Däremot anser eleverna att laborationer utvecklar deras förståelse för naturkunskap. Undersökningen visar också att eleverna är osäkra på lärarens syfte och de förstår inte alltid vad laborationen ska ge för kunskap. Detta visar att det är viktigt att laborationsinstruktioner tydliggör syftet och den kunskap det är meningen att laborationen ska ge. Dessutom har diskussionerna under laborationen stor betydelse för lärandet av naturvetenskap.</p><p>Nyckelord: Förståelse, kunskap, laborationer/experiment/praktiskt arbete, syfte/mål</p> / <p>Abstract</p><p>Laboratory experiments in science are a natural part of the education. The purpose of this composition is to find out whether one removes a possibility of learning and understanding for students if one does not use laboratory experiments in education. Moreover, I wanted to examine if teachers and students are of the opinion that laboratory experiments help in deepening the understanding of natural science, and if the students understand the purposes of these experiments.</p><p>To carry out the study, qualitative interviews were made with four teachers and six students at an upper secondary school. Result shows that teachers are of different opinions about the importance of the laboratory experiments for the understanding of the subject. However, the students’ opinions are that laboratory experiments help in deepening their understanding for natural science. The study also shows that students feel uncertain of the teacher’s purpose and what knowledge the laboratory experiment is meant to give. This shows that it is important to explain the purpose of the experiment, and what knowledge it is meant to give, in laboratory instructions. Furthermore, the discussions during laboratory work are of considerable significance for learning natural science.</p><p>Keywords: Understanding, knowledge, laboratory experiments/experiments/practical work, purpose</p>

Sammanfattning Laborationer i naturvetenskapliga ämnen är en naturlig del av undervisningen. Syftet med den här uppsatsen är att ta reda på om man tar bort en möjlighet till inlärning och förståelse för eleverna om laborationer inte används i undervisningen. Vidare ville jag undersöka om lärare och elever anser att laborationer utvecklar förståelsen av naturvetenskap, dessutom om eleverna förstår syftena med laborationerna. Undersökningen utfördes genom att kvalitativa intervjuer gjordes med fyra lärare och sex elever i en gymnasieskola. Resultatet visar att lärarna har olika åsikter om laborationens betydelse för förståelsen av ämnet. Däremot anser eleverna att laborationer utvecklar deras förståelse för naturkunskap. Undersökningen visar också att eleverna är osäkra på lärarens syfte och de förstår inte alltid vad laborationen ska ge för kunskap. Detta visar att det är viktigt att laborationsinstruktioner tydliggör syftet och den kunskap det är meningen att laborationen ska ge. Dessutom har diskussionerna under laborationen stor betydelse för lärandet av naturvetenskap. Nyckelord: Förståelse, kunskap, laborationer/experiment/praktiskt arbete, syfte/mål / Abstract Laboratory experiments in science are a natural part of the education. The purpose of this composition is to find out whether one removes a possibility of learning and understanding for students if one does not use laboratory experiments in education. Moreover, I wanted to examine if teachers and students are of the opinion that laboratory experiments help in deepening the understanding of natural science, and if the students understand the purposes of these experiments. To carry out the study, qualitative interviews were made with four teachers and six students at an upper secondary school. Result shows that teachers are of different opinions about the importance of the laboratory experiments for the understanding of the subject. However, the students’ opinions are that laboratory experiments help in deepening their understanding for natural science. The study also shows that students feel uncertain of the teacher’s purpose and what knowledge the laboratory experiment is meant to give. This shows that it is important to explain the purpose of the experiment, and what knowledge it is meant to give, in laboratory instructions. Furthermore, the discussions during laboratory work are of considerable significance for learning natural science. Keywords: Understanding, knowledge, laboratory experiments/experiments/practical work, purpose

Subjects in laboratory experiments are prone to effects of social desirability. This reactive behavior is due to the subjects perceived anonymity in the entire experiment. Especially, socially desirable behavior is also triggered by assembling and/or payment procedures that are not anonymous. Indeed, in a laboratory experiments with a one-shot prisoner’s dilemma (PD) and perfect stranger anonymity subjects (n=174) showed significantly different cooperation rates depending on the anonymity conditions during assembling and the payment procedure, ranging from 33.3% to 19.9%. In addition, a first experiment with the PD and anonymous payment and double blind experimenting lead to a cooperation rate of 33.3%. Only after the same subjects (n=34) took part a second time in same, entire experiment, the cooperation rate fell to 8.8%. Therefore this measurement of the cooperation rates in a laboratory experiment failed the test-retest check on reliability. This happened though all manipulations used fulfilled the standards of fully anonymous experimenting. This means that such processes could go unnoticed and bias the results of any standard laboratory experiment on cooperation in one shot decisions. Therefore, in accordance with the textbook logic of laboratory experiments, but in contrast to a common practice (cf. Behavioral Game Theory) marginal totals from cooperation experiments in the laboratory should not be interpreted.

Foram estudados cinco casos históricos de escorregamentos ocorridos na cidade de Salvador - Bahia, através do levantamento e tratamento dos dados preexistentes. Também foram realizados ensaios complementares através da instrumentação em campo com tensiômetros e ensaios de laboratório. A retroanálise, objetivo central desse trabalho foi realizada a partir das geometrias de cada uma das encostas, antes e após a ruptura resultando na definição dos possíveis parâmetros médios de resistência ao cisalhamento. Secundariamente foram realizadas análises de estabilidade convencional para a avaliação dos fatores de segurança de cada encosta, com os parâmetros de resistência na condição não saturada e saturada. Por fim foram efetuadas simulações numéricas que visavam reproduzir as condições que levaram à ruptura da encosta do Alto do Bom Viver, baseado nos conceitos da mecânica dos solos não saturados. Os resultados mostram que a maioria dos escorregamentos estudados, ocorre no horizonte do solo residual maduro, onde o valor de ângulo de atrito médio é 34º, condizente com as superfícies de rupturas pouco profundas observadas em campo. As análises paramétricas sugerem que o mecanismo de ruptura mais provável esteja relacionado à diminuição da coesão aparente do solo em virtude da diminuição da sucção. / Five historical cases of landslides in the city of Salvador, Bahia, were studied through the survey and treatment of the preexistent data. Complementary experiments were accomplished through the instrumentation field using tensiometers and laboratory testing. The back-analysis, main objective of this research, was accomplished through the geometries of each slope, before and after the rupture, resulting in the definition of the possible medium parameters of resistance to shear. Secondary, analysis of the conventional stability to the evaluation of safety factors of each slope was accomplished, with the parameters of resistance in the unsaturated and saturated condition. At last, numerical simulations were done, aiming at reproducing the conditions which led to the rupture of the slope of Alto do Bom Viver, based on the concepts of mechanics of non saturated soil. The results demonstrated that the majority of the slips studied occur in the horizon of the mature residual soil, where the value of the angle of the medium attrition is of 34 degrees, suitable with the surface of little deep ruptures observed in the field. The parametric analysis suggests that the most probable mechanism of rupture is related to the decrease of the apparent cohesion of the soil due to the decrease of suction.