Peaks, Cliffs, and Valleys: The Peculiar Incentives in Teacher Retirement Systems and Their Consequences for School Staffing

This article examines the pattern of incentives for work versus retirement in six state teacher pension systems. We do this by examining the annual accrual of pension wealth from an additional year of work over a teacher's career. Accrual of wealth is highly nonlinear and heavily loaded at arbitrary years that would normally be considered mid-career. One typical pattern exhibits low accrual in early years, accelerating in the mid- to late fifties, followed by dramatic decline or even negative returns in years that are relatively young for retirement. Key factors in the defined benefit formulas that drive such patterns are identified along with likely consequences for employee behavior. The authors examine efficiency and equity consequences of these systems as well as options for reform

Effect of Nanocrystalline Diamond Films Deflection on Wear Observed in Reciprocating Sliding Tests

The present study deals with the tribological behavior of nanocrystalline diamond (NCD) films. The diamond films were deposited by microwave plasma enhanced chemical vapor deposition (MPCVD) in methane/hydrogen/air plasma on the Si(100) substrates. The tribological properties were studied by reciprocal sliding tests against Si3N4 balls. The depth profiles and surface morphology of the wear scars were investigated by means of mechanical profilometry and scanning electron microscopy (SEM). Various adaptation processes occur between contacting surfaces including asperity polishing, formation of carbonaceous tribolayer and ripple patterns on the wear scar surfaces. The film deflection is the specific form of adaptation decreasing contact pressure and, therefore, the damage (including wear) of both counter bodies. The deflection of NCD films in sliding tests can be related with the effect of fatigue

Recent progress and perspectives of space electric propulsion systems based on smart nanomaterials

Miniaturized spacecraft built from advanced nanomaterials are poised for unmanned space exploration. In this review, the authors examine the integration of nanotechnology in electric propulsion systems and propose the concept of self-healing and adaptive thrusters

É atrativo tornar-se professor do Ensino Médio no Brasil?: Evidências com base em decomposições paramétricas e não paramétricas

Neste artigo avalia-se a atratividade da ocupação de professor do Ensino Médio, tal como expressa por diferenciais salariais entre essa categoria de professores e três grupos de comparação. Os dados provêm da PNAD, anos de 2006 e 2009, e as metodologias empregadas são a tradicional decomposição de Oaxaca-Blinder e uma alternativa não paramétrica proposta por Ñopo (2008), que decompõe em quatro termos o diferencial total, destacando o diferencial dentro de um suporte comum de características observáveis. Os resultados indicam que professores do Ensino Médio possuem diferencial de remuneração favorável, porém decrescente, quando comparados a funcionários públicos e empregados do setor privado. Além disso, e de modo mais preocupante, em comparação a profissionais com qualificação semelhante, a situação é desfavorável aos professores, e mostra deterioração de 2006 para 2009. Resultados obtidos utilizando ambas as metodologias indicam que este último diferencial em grande medida não é atribuível às diferenças nas distribuições de características individuais, mas muito mais à parcela não explicada, o que pode representar baixa valorização social de professores ou diferenciais de produtividade pré-escolha ocupacional ou pós-escolha ocupacional. Qualquer que seja a razão, o déficit de remuneração no mercado de trabalho docente pode ser um dos fatores explicativos do baixo interesse de jovens talentosos pelas licenciaturas com potenciais impactos negativos sobre a qualidade do aprendizado dos futuros alunos

Serving the Public Interest in Several Ways: Theory and Empirics

We develop a model where people differ in their altruistic preferences and can serve the public interest in two ways: by making donations to charity and by taking a public service job and exerting effort on the job. Our theory predicts that people who are more altruistic are more likely to take a public service job and, for a given job, make higher donations to charity. Comparing equally altruistic workers, those with a regular job make higher donations to charity than those with a public service job by a simple substitution argument. We subsequently test these predictions using cross-sectional data from Germany on self-reported altruism, sector of employment, and donations to charity. In addition, we use panel data from the Netherlands on volunteering and sector of employment. We find support for most of our predictions.Hervorming Sociale Regelgevin