Put your money where your butt is : a commitment contract for smoking cessation

The authors designed and tested a voluntary commitment product to help smokers quit smoking. The product (CARES) offered smokers a savings account in which they deposit funds for six months, after which they take a urine test for nicotine and cotinine. If they pass, their money is returned; otherwise, their money is forfeited to charity. Eleven percent of smokers offered CARES tookup, and smokers randomly offered CARES were 3 percentage points more likely to pass the 6-month test than the control group. More importantly, this effect persisted in surprise tests at 12 months, indicating that CARES produced lasting smoking cessation.Tobacco Use and Control,Health Monitoring&Evaluation,Disease Control&Prevention,Alcohol and Substance Abuse,Adolescent Health

Primary Surplus Behavior and Risks to Fiscal Sustainability in Emerging Market Countries: A "Fan-Chart" Approach

This paper proposes a probabilistic approach to public debt sustainability analy-sis (DSA) using "fan charts." These depict the magnitude of risks-upside and downside-surrounding public debt projections as a result of uncertain economic conditions and policies. We propose a simulation algorithm for the path of public debt under realistic shock configurations, combining pure economic disturbances (to growth, interest rates, and exchange rates), the endogenous policy response to these, and the possible shocks arising from fiscal policy itself. The paper empha-sizes the role of fiscal behavior, as well as the structure of disturbances facing the economy and due to fiscal policy, in shaping the risk profile of public debt. Fan charts for debt are derived from the "marriage" between the pattern of shocks on the one hand and the endogenous response of fiscal policy on the other. Applications to Argentina, Brazil, Mexico, South Africa, and Turkey are used to illustrate the approach and its limitations. Copyright 2006, International Monetary Fund

Microfinance games

Microfinance has been heralded as an effective way to address imperfections in credit markets. But from a theoretical perspective, the success of microfinance contracts has puzzling elements. In particular, the group-based mechanisms often employed are vulnerable to free-riding and collusion, although they can also reduce moral hazard and improve selection. The authors created an experimental economics laboratory in a large urban market in Lima, Peru and over seven months conducted 11 different games that allow them to unpack microfinance mechanisms in a systematic way. They find that risk-taking broadly conforms to predicted patterns, but that behavior is safer than optimal. The results help to explain why pioneering microfinance institutions have been moving away from group-based contracts.Banks&Banking Reform,Insurance&Risk Mitigation,Financial Intermediation,Social Accountability,Civic Participation and Corporate Governance

Microfinance Games

Microfinance has been heralded as an effective way to address imperfections in credit markets. From a theoretical perspective, however, the success of microfinance contracts has puzzling elements. In particular, the group-based mechanisms often employed are vulnerable to free-riding and collusion, although they can also reduce moral hazard and improve selection. We created an experimental economics laboratory in a large urban market in Lima, Peru and over seven months conducted eleven different games that allow us to unpack microfinance mechanisms in a systematic way. We find that risk-taking broadly conforms to predicted patterns, but that behavior is safer than optimal. The results help to explain why pioneering microfinance institutions have been moving away from group-based contracts. The work also provides an example of how to use framed field experiments as a methodological bridge between laboratory and field experiments.microfinance, group lending, information asymmetries, contract theory, experimental economics

Microfinance Games

Microfinance has been heralded as an effective way to address imperfections in credit markets. From a theoretical perspective, however, the success of microfinance contracts has puzzling elements. In particular, the group-based mechanisms often employed are vulnerable to free-riding and collusion, although they can also reduce moral hazard and improve selection. We created an experimental economics laboratory in a large urban market in Lima, Peru and over seven months conducted eleven different games that allow us to unpack microfinance mechanisms in a systematic way. We find that risk-taking broadly conforms to predicted patterns, but that behavior is safer than optimal. The results help to explain why pioneering microfinance institutions have been moving away from group-based contracts.Microfinance, Group Lending, Information Asymmetries, Contract Theory, Experimental Economics

Streamlining Sound Speed Profile Pre-Processing: Case Studies and Field Trials

High rate sound speed profiling systems have the potential to maximize the efficiency of multibeam echosounder systems (MBES) by increasing the accuracy at the outer edges of the swath where refraction effects are at their worst. In some cases, high rate sampling on the order of tens of casts per hour is required to capture the spatio-temporal oceanographic variability and this increased sampling rate can challenge the data acquisition workflow if refraction corrections are to be applied in real-time. Common bottlenecks result from sound speed profile (SSP) preprocessing requirements, e.g. file format conversion, cast extension, reduction of the number of points in the cast, filtering, etc. Without the ability to quickly pre-process SSP data, the MBES operator can quickly become overwhelmed with SSP related tasks, potentially to the detriment of their other duties. A series of algorithms are proposed in which SSPs are automatically pre-processed to meet input criteria of MBES acquisition systems, specifically the problems of cast extrapolation and thinning are addressed. The algorithmic performance will be assessed in terms of sounding uncertainty through a series of case studies in a variety of oceanographic conditions and water depths. Results from a field trial in the French Mediterranean will be used to assess the improvement in real-time MBES acquisition workflow and survey accuracy and will also highlight where further improvements can be made in the pre-processing pipeline

Developing Predictive Molecular Maps of Human Disease through Community-based Modeling

The failure of biology to identify the molecular causes of disease has led to disappointment in the rate of development of new medicines. By combining the power of community-based modeling with broad access to large datasets on a platform that promotes reproducible analyses we can work towards more predictive molecular maps that can deliver better therapeutics

Effects of Aging on Epoxy-Based Rapid Tooling Materials

This study shows the effects of aging on epoxy-based rapid tooling materials. Two epoxy-acrylate resins used for stereolithography and one aluminum powder-filled epoxy used for the high speed machining of plastic injection molds were selected to investigate their aging behavior in different environments. Four different conditions, each characterized by a specific relative humidity, were used to perform a seven week long aging study. Temperature was kept constant at 30°C. Both stereolithographic resins showed a drop in mechanical properties and in their glass transition temperatures in wet environments, whereas aging time showed little influence on these properties. Moisture uptake is mainly responsible for that drop and coefficients of water diffusion were determined. On the other hand, the aluminum powder-filled epoxy showed little humidity-dependent drop in mechanical properties and in its glass transition temperature during aging. This result correlates well with the very low moisture absorption of this material.This work has been made possible thanks to the National Science Foundation (DMI9618039) and the Rapid Prototyping and Manufacturing Institute.Mechanical Engineerin

Robust model-based analysis of single-particle tracking experiments with Spot-On.

Single-particle tracking (SPT) has become an important method to bridge biochemistry and cell biology since it allows direct observation of protein binding and diffusion dynamics in live cells. However, accurately inferring information from SPT studies is challenging due to biases in both data analysis and experimental design. To address analysis bias, we introduce 'Spot-On', an intuitive web-interface. Spot-On implements a kinetic modeling framework that accounts for known biases, including molecules moving out-of-focus, and robustly infers diffusion constants and subpopulations from pooled single-molecule trajectories. To minimize inherent experimental biases, we implement and validate stroboscopic photo-activation SPT (spaSPT), which minimizes motion-blur bias and tracking errors. We validate Spot-On using experimentally realistic simulations and show that Spot-On outperforms other methods. We then apply Spot-On to spaSPT data from live mammalian cells spanning a wide range of nuclear dynamics and demonstrate that Spot-On consistently and robustly infers subpopulation fractions and diffusion constants