Why (and When) are Preferences Convex? Threshold Effects and Uncertain Quality

It is often assumed (for analytical convenience, but also in accordance with common intuition) that consumer preferences are convex. In this paper, we consider circumstances under which such preferences are (or are not) optimal. In particular, we investigate a setting in which goods possess some hidden quality with known distribution, and the consumer chooses a bundle of goods that maximizes the probability that he receives some threshold level of this quality. We show that if the threshold is small relative to consumption levels, preferences will tend to be convex; whereas the opposite holds if the threshold is large. Our theory helps explain a broad spectrum of economic behavior (including, in particular, certain common commercial advertising strategies), suggesting that sensitivity to information about thresholds is deeply rooted in human psychology.

Demográfiai hatások és implicit hozamok kapcsolata a nyugdíjrendszerekben = The relationship of demographic effects and implicit returns in pension systems

E tanulmány központi témája a nyugdíjrendszerek implicit hozama. Az együtt élő nemzedékek figyelembevételével felépülő nyugdíjmodellekben kétféle implicit hozamot különböztetünk meg. A hosszmetszeti implicit hozamot valamely adott nemzedékhez tartozó, különböző években esedékes pénzáramlások alapján, a keresztmetszeti implicit hozamot pedig több, különböző nemzedék adott évben jellemző pénzáramlásai alapján számíthatjuk ki. A hosszmetszeti és keresztmetszeti implicit hozamok értékeit és a közük lévő összefüggéseket a tőkefedezeti, a névleges egyéni számlás és a hagyományos felosztó-kirovó nyugdíjrendszerek egyszerű elméleti modelljeiben hasonlítjuk össze. A számításokhoz használt modellkeret fontos eleme a várható élettartam figyelembevétele. Az eredmények azt mutatják, hogy a maximális és a várható élettartam eltérésekor a hosszmetszeti és a keresztmetszeti implicit hozamok közötti összefüggések még egyszerű elméleti modellben is meglehetősen összetettek lehetnek. ____ The focus of this study is on the implicit returns of pension systems. Two types are analysed using an overlapping generations model: the calculation of longitudinal\" return is based on cash flows in different years belonging to a given generation, while cross-section\" implicit return is calculated in a given year with cash flows of multiple generations. Values and relationships of longitudinal and cross-section implicit returns are compared in simple theoretical models of fully funded\", notional defined-contribution\" and traditional pay-as-you-go\" pension systems. An important element of the theoretical model is the inclusion of an assumption about life expectancy. Model results point to the complexity of the relation between longitudinal and cross-section implicit returns, if expected and maximum life expectancy differ. The study maps and introduces these complex relationships.

School Segregation, Educational Disparities, and Impacts on Haitian Youth in South Florida

This paper examines the ways in which the legacy of school segregation in South Florida has affected the education of Haitian students and continues to limit their prospects. The high schools that serve neighborhoods with concentrated Haitian populations achieve shockingly poor academic results, which negatively affect Haitian student academic achievement.

The effects and extent of 1,1,1-trichloroethane vapor concentration exposure on workers during solvent vapor degreasing

This study attempted to determine if an excessive amount of 1,1,1 - Trichloroethane was released into the air, the acute effects of exposure and the cause(s) of excessive use. The types of degreasing equipments which were tested in this study are straight vapor and the vapor spray machines. The instruments utilized to obtain the data for this study are Gastech Haline Detector, Organic Vapor Monitor Badge and Personal Sampling Pump. Readings were taken on three different tanks. The data accumulated by this study were obtained during actual cleaning operation. During testing, increased exposure was detected due to exceeding the rate of removal, downward drafts were blowing right over the top of a degreaser and, in some cases, poor general ventilation caused solvent vapor to be blown out of the tank and into the workers' breathing zone, affecting excessive vapor drag out and solvent loss. The results show that, since the characteristics of solvent 1,1,1 - Trichloroethane are well suited to vapor degreasing requirements, by using proper procedures and maintenance, 1,1,1 - Trichloroethane emission during vapor degreasing can be controlled at levels well below the industrial hygiene standard established by OSHA for safe and healthful conditions.

Operational expenditure costs for wave energy projects and impacts on financial returns

This paper examines 'availability' and the input metrics of operational expenditure (OPEX) for wave energy projects and reports on a case study which assesses the impact of these inputs on project profit returns. Case study simulations modelled a 75 MW wave energy project at two locations; the west coast of Ireland and the north coast of Portugal. Access and availability with respect to weather windows at both locations are discussed and their impact on energy output and wave farm operations is quantified. The input metrics used to calculate OPEX of wave energy projects are defined as well as the impact of OPEX on project net present value (NPV) and internal rate of return (IRR). Results indicate that access and resultant availability factors have a significant impact on case study results by reducing energy output and correspondingly financial returns. Furthermore, the technology maturity level designated for a project also impacts on availability factors and consequently energy output and NPV. Case study profits proved to be very sensitive to annual OPEX, especially if overhaul and replacement costs were accounted for. As a result of the impact of 'availability' on project profit returns. Feed-in tariffs will need to be tailored to the location in question as well as the device technology maturity level, with case study simulations indicating that high FIT will be required to support early stage WEC projects. (C) 2012 Elsevier Ltd. All rights reserved.

Physical Insights, Steady Aerodynamic Effects, and a Design Tool for Low-Pressure Turbine Flutter

The successful, efficient, and safe turbine design requires a thorough understanding of the underlying physical phenomena. This research investigates the physical understanding and parameters highly correlated to flutter, an aeroelastic instability prevalent among low pressure turbine (LPT) blades in both aircraft engines and power turbines. The modern way of determining whether a certain cascade of LPT blades is susceptible to flutter is through time-expensive computational fluid dynamics (CFD) codes. These codes converge to solution satisfying the Eulerian conservation equations subject to the boundary conditions of a nodal domain consisting fluid and solid wall particles. Most detailed CFD codes are accompanied by cryptic turbulence models, meticulous grid constructions, and elegant boundary condition enforcements all with one goal in mind: determine the sign (and therefore stability) of the aerodynamic damping. The main question being asked by the aeroelastician, ``is it positive or negative?'' This type of thought-process eventually gives rise to a black-box effect, leaving physical understanding behind. Therefore, the first part of this research aims to understand and reveal the physics behind LPT flutter in addition to several related topics including acoustic resonance effects. A percentage of this initial numerical investigation is completed using an influence coefficient approach to study the variation the work-per-cycle contributions of neighboring cascade blades to a reference airfoil. The second part of this research introduces new discoveries regarding the relationship between steady aerodynamic loading and negative aerodynamic damping. Using validated CFD codes as computational wind tunnels, a multitude of low-pressure turbine flutter parameters, such as reduced frequency, mode shape, and interblade phase angle, will be scrutinized across various airfoil geometries and steady operating conditions to reach new design guidelines regarding the influence of steady aerodynamic loading and LPT flutter. Many pressing topics influencing LPT flutter including shocks, their nonlinearity, and three-dimensionality are also addressed along the way. The work is concluded by introducing a useful preliminary design tool that can estimate within seconds the entire aerodynamic damping versus nodal diameter curve for a given three-dimensional cascade.

Musculoskeletal effects and injury risk in collegiate Indian classical and ballet dancers

Dancers of all forms often engage in aesthetic yet challenging movements. Their training, choreography, and performances require strength, stamina, flexibility, grace, passion, and emotion. Ballet and Bharatanatyam (an Indian classical dance form) dancers utilize two movements in each of their dance forms that are similar—a half-sitting pose and a full-sitting pose, both requiring external rotation of the legs and bending at the knee joints. The purpose of this study was to examine and compare the biomechanics of joint reaction forces and knee angles in both styles of dance for these particular poses. The study included nine female ballet dancers and seven female Bharatanatyam dancers. Hamstring and gastrocnemius flexibility were measured for each dancer. Knee angles, vertical peak forces, and moments were determined for dancers at the lowest point of their bending positions. Mann-Whitney U tests found significant differences in hamstring flexibility, right gastrocnemius flexibility, and knee angles for the full-sitting poses between ballet and Bharatanatyam dancers. No significant difference was found in the vertical peak forces as a ratio to total body weight and moments between the two styles of dance. Further research can be done to more directly assess a difference in injury risk between the ballet and Bharatanatyam dancers.

Biomass, quality traits and methane production of extensive grassland: biodiversity effects and sensor approaches

Energy policies around the world are mandating for a progressive increase in renewable energy production. Extensive grassland areas with low productivity and land use limitations have become target areas for sustainable energy production to avoid competition with food production on the limited available arable land resources and minimize further conversion of grassland into intensively managed energy cropping systems or abandonment. However, the high spatio-temporal variability in botanical composition and biochemical parameters is detrimental to reliable assessment of biomass yield and quality regarding anaerobic digestion. In an approach to assess the performance for predicting biomass using a multi-sensor combination including NIRS, ultra-sonic distance measurements and LAI-2000, biweekly sensor measurements were taken on a pure stand of reed canary grass (Phalaris aruninacea), a legume grass mixture and a diversity mixture with thirty-six species in an experimental extensive two cut management system. Different combinations of the sensor response values were used in multiple regression analysis to improve biomass predictions compared to exclusive sensors. Wavelength bands for sensor specific NDVI-type vegetation indices were selected from the hyperspectral data and evaluated for the biomass prediction as exclusive indices and in combination with LAI and ultra-sonic distance measurements. Ultrasonic sward height was the best to predict biomass in single sensor approaches (R² 0.73 – 0.76). The addition of LAI-2000 improved the prediction performance by up to 30% while NIRS barely improved the prediction performance. In an approach to evaluate broad based prediction of biochemical parameters relevant for anaerobic digestion using hyperspectral NIRS, spectroscopic measurements were taken on biomass from the Jena-Experiment plots in 2008 and 2009. Measurements were conducted on different conditions of the biomass including standing sward, hay and silage and different spectroscopic devices to simulate different preparation and measurement conditions along the process chain for biogas production. Best prediction results were acquired for all constituents at laboratory measurement conditions with dried and ground samples on a bench-top NIRS system (RPD > 3) with a coefficient of determination R2 < 0.9. The same biomass was further used in batch fermentation to analyse the impact of species richness and functional group composition on methane yields using whole crop digestion and pressfluid derived by the Integrated generation of solid Fuel and Biogas from Biomass (IFBB) procedure. Although species richness and functional group composition were largely insignificant, the presence of grasses and legumes in the mixtures were most determining factors influencing methane yields in whole crop digestion. High lignocellulose content and a high C/N ratio in grasses may have reduced the digestibility in the first cut material, excess nitrogen may have inhibited methane production in second cut legumes, while batch experiments proved superior specific methane yields of IFBB press fluids and showed that detrimental effects of the parent material were reduced by the technical treatment

Neoliberal and Neoconservative Immiseration Capitalism in England: Policies and Impacts on Society and on Education

In this article we firstly set out the facts about the current stage of capitalism, the Immiseration stage of neoliberal capitalism in England. We note its relationship with conservatism and neo-conservatism. We identify increased societal inequalities, the assault by the capitalist state on its opponents, and proceed to describe and analyse what neoliberalism and neo-conservatism have done and are doing to education in England- in the schools, further education, and university sectors. We present two testimonies about the impacts of neoliberalism/ neo-conservatism, one from the school sector, one from the further / vocational education sector, as a means of describing, analysing, and then theorising the parameters of the neoliberal/ neoconservative restructuring education and its impacts. We conclude by further theorising this. With the election of a Conservative majority in the 7 May 2015 general election in the UK, the policies and processes of neoliberalisation and neoconservatisation are being intensified.

Memory effects and geometrical considerations in open quantum systems

This thesis discusses memory effects in open quantum systems with an emphasis on the Breuer, Laine, Piilo (BLP) measure of non-Markovianity. It is shown how the calculation of the measure can be simplifed and how quantum information protocols can bene t from memory e ects. The superdense coding protocol is used as an example of this. The quantum Zeno effect will also be studied from the point of view of memory e ects. Finally the geometric ideas used in simplifying the calculation of the BLP measure are applied in studying the amount of resources needed for detecting bipartite quantum correlations. It is shown that to decide without prior information if an unknown quantum state is entangled or not, an informationally complete measurement is required. The first part of the thesis contains an introduction to the theoretical ideas such as quantum states, closed and open quantum systems and necessary mathematical tools. The theory is then applied in the second part of the thesis as the results obtained in the original publications I-VI are presented and discussed.

Identifying treatment effects and counterfactual distributions using data combination with unobserved heterogeneity

This paper considers identification of treatment effects when the outcome variables and covari-ates are not observed in the same data sets. Ecological inference models, where aggregate out-come information is combined with individual demographic information, are a common example of these situations. In this context, the counterfactual distributions and the treatment effects are not point identified. However, recent results provide bounds to partially identify causal effects. Unlike previous works, this paper adopts the selection on unobservables assumption, which means that randomization of treatment assignments is not achieved until time fixed unobserved heterogeneity is controlled for. Panel data models linear in the unobserved components are con-sidered to achieve identification. To assess the performance of these bounds, this paper provides a simulation exercise.

Distributional effects and individual differences in L2 morphology learning

Second language (L2) learning outcomes may depend on the structure of the input and learners’ cognitive abilities. This study tested whether less predictable input might facilitate learning and generalization of L2 morphology while evaluating contributions of statistical learning ability, nonverbal intelligence, phonological short-term memory, and verbal working memory. Over three sessions, 54 adults were exposed to a Russian case-marking paradigm with a balanced or skewed item distribution in the input. Whereas statistical learning ability and nonverbal intelligence predicted learning of trained items, only nonverbal intelligence also predicted generalization of case-marking inflections to new vocabulary. Neither measure of temporary storage capacity predicted learning. Balanced, less predictable input was associated with higher accuracy in generalization but only in the initial test session. These results suggest that individual differences in pattern extraction play a more sustained role in L2 acquisition than instructional manipulations that vary the predictability of lexical items in the input.

Promotion and diffusion of tha career Bachelor and Licenciature of Mathematics Teaching in rural areas of Costa Rica project: effects and results

This article describes the purpose and activities of the project Promoting Mathematics Education in Rural Areas of Costa Rica. The activity has focused on two objectives. First, supporting and monitoring students who have expressed interest in studying a mathematics teacher. To achieve this, it has been working with students who have an ideal profile for the career, mainly from rural areas. The second objective is to conduct training workshops for high school in-service teachers, to strengthen and improve their knowledge in the area of mathematics. Among the results of the project, it can be highlighted a significant increase in the enrollment of students in the career of Mathematics Education in 2010 and 2011, and the training processes in the field of Real Functions of Real Variable and Geometry at different regional areas mostly rural as Aguirre, Sarapiquí, Coto, Buenos Aires, Limón, Cañas, Pérez Zeledón, Nicoya, Los Santos, Turrialba, Puriscal, Desamparados, San Carlos, Puntarenas, Limón, Liberia, Santa Cruz y Upala.