Estimating Bayesian decision problems with heterogeneous priors

In many areas of economics there is a growing interest in how expertise andpreferences drive individual and group decision making under uncertainty. Increasingly, we wish to estimate such models to quantify which of these drive decisionmaking. In this paper we propose a new channel through which we can empirically identify expertise and preference parameters by using variation in decisionsover heterogeneous priors. Relative to existing estimation approaches, our \Prior-Based Identification" extends the possible environments which can be estimated,and also substantially improves the accuracy and precision of estimates in thoseenvironments which can be estimated using existing methods.

Characterization of 13 polymorphic microsatellite loci for two land snail species, Trochulus villosus and T. sericeus (Gastropoda: Pulmonata: Hygromiidae).

Thirteen new microsatellite loci were isolated and tested on two land snail species, Trochulus villosus and T. sericeus (Pulmonata: Hygromiidae), resulting in a set of eight polymorphic markers for each species. The expected heterozygosity was high for all loci and species (between 0.616 and 0.944). Such levels of variability will allow detailed insights into the population genetic structure of some Trochulus species.

Efficacy of brief motivational intervention at army conscription to address alcohol use and related problems: a randomized controlled trial

Objectives: The aim of this study was to evaluate the efficacy of brief motivational intervention (BMI) in reducing alcohol use and related problems among binge drinkers randomly selected from a census of 20 year-old French speaking Swiss men and to test the hypothesis that BMI contributes to maintain low-risk drinking among non-bingers. Methods: Randomized controlled trial comparing the impact of BMI on weekly alcohol use, frequency of binge drinking and occurrence of alcohol-related problems. Setting: Army recruitment center. Participants: A random sample of 622 men were asked to participate, 178 either refused, or missed appointment, or had to follow military assessment procedures instead, resulting in 418 men randomized into BMI or control conditions, 88.7% completing the 6-month follow-up assessment. Intervention: A single face-to-face BMI session exploring alcohol use and related problems in order to stimulate behaviour change perspective in a non-judgmental, empathic manner based on the principles of motivational interviewing (MI). Main outcome measures: Weekly alcohol use, binge drinking frequency and the occurrence of 12 alcohol-related consequences. Results: Among binge drinkers, we observed a 20% change in drinking induced by BMI, with a reduction in weekly drinking of 1.5 drink in the BMI group, compared to an increase of 0.8 drink per week in the control group (incidence rate ratio 0.8, 95% confidence interval 0,66 to 0,98, p = 0.03). BMI did not influence the frequency of binge drinking and the occurrence of 12 possible alcohol-related consequences. However, BMI induced a reduction in the alcohol use of participants who, after drinking over the past 12 months, experienced alcohol-related consequences, i.e., hangover (-20%), missed a class (-53%), got behind at school (-54%), argued with friends (-38%), engaged in unplanned sex (-45%) or did not use protection when having sex (-64%). BMI did not reduce weekly drinking in those who experienced the six other problems screened. Among non-bingers, BMI did not contribute to maintain low-risk drinking. Conclusions: At army conscription, BMI reduced alcohol use in binge drinkers, particularly in those who recently experienced alcohol-related adverse consequences. No preventive effect of BMI was observed among non-bingers. BMI is an interesting preventive option in young binge drinkers, particularly in countries with mandatory army recruitment.

Median problems in networks

The P-median problem is a classical location model par excellence . In this paper we, firstexamine the early origins of the problem, formulated independently by Louis Hakimi andCharles ReVelle, two of the fathers of the burgeoning multidisciplinary field of researchknown today as Facility Location Theory and Modelling. We then examine some of thetraditional heuristic and exact methods developed to solve the problem. In the third sectionwe analyze the impact of the model in the field. We end the paper by proposing new lines ofresearch related to such a classical problem.

Enforcement problems and secondary markets

There is a large and growing literature that studies the effects of weak enforcement institutions on economic performance. This literature has focused almost exclusively on primary markets, in which assets are issued and traded to improve the allocation of investment and consumption. The general conclusion is that weak enforcement institutions impair the workings of these markets, giving rise to various inefficiencies.But weak enforcement institutions also create incentives to develop secondary markets, in which the assets issued in primary markets are retraded. This paper shows that trading in secondary markets counteracts the effects of weak enforcement institutions and, in the absence of further frictions, restores efficiency.

On certain greedoid polyhedra, partially indexable scheduling problems and extended restless bandit allocation indices

We present a polyhedral framework for establishing general structural properties on optimal solutions of stochastic scheduling problems, where multiple job classes vie for service resources: the existence of an optimal priority policy in a given family, characterized by a greedoid(whose feasible class subsets may receive higher priority), where optimal priorities are determined by class-ranking indices, under restricted linear performance objectives (partial indexability). This framework extends that of Bertsimas and Niño-Mora (1996), which explained the optimality of priority-index policies under all linear objectives (general indexability). We show that, if performance measures satisfy partial conservation laws (with respect to the greedoid), which extend previous generalized conservation laws, then theproblem admits a strong LP relaxation over a so-called extended greedoid polytope, which has strong structural and algorithmic properties. We present an adaptive-greedy algorithm (which extends Klimov's) taking as input the linear objective coefficients, which (1) determines whether the optimal LP solution is achievable by a policy in the given family; and (2) if so, computes a set of class-ranking indices that characterize optimal priority policies in the family. In the special case of project scheduling, we show that, under additional conditions, the optimal indices can be computed separately for each project (index decomposition). We further apply the framework to the important restless bandit model (two-action Markov decision chains), obtaining new index policies, that extend Whittle's (1988), and simple sufficient conditions for their validity. These results highlight the power of polyhedral methods (the so-called achievable region approach) in dynamic and stochastic optimization.

Solving higher-dimensional continuous time stochastic control problems by value function regression

The paper develops a method to solve higher-dimensional stochasticcontrol problems in continuous time. A finite difference typeapproximation scheme is used on a coarse grid of low discrepancypoints, while the value function at intermediate points is obtainedby regression. The stability properties of the method are discussed,and applications are given to test problems of up to 10 dimensions.Accurate solutions to these problems can be obtained on a personalcomputer.

Skin problems associated with pegylated liposomal doxorubicin-more than palmoplantar erythrodysesthesia syndrome.

Liposomal pegylated doxorubicin is an encapsulation form of doxorubicin, with an improved pharmacokinetic profile and the ability to selectively accumulate into tumor tissue. As a result, the tolerated dose of the drug can be increased, followed by a reduced incidence of neutropenia and cardiotoxicity in comparison to doxorubucin treatment. However, a common adverse dose-schedule limiting effect of the treatment is palmoplantar erythrodysesthesia syndrome. In this retrospective study we included six patients hospitalised in the University Hospital of Zurich during the last 2 years, in connection with side effects caused by pegylated liposomal doxorubicin. These patients received this chemotherapeutic agent for treatment of various malignancies such as breast cancer, ovarian cancer, mycosis fungoides and cutaneous B-cell lymphoma. Three of six patients in this study developed classical palmoplantar erythrodysesthesia, one developed palmoplantar erythrodysesthesia associated with extensive bullous disease, one developed eruption of lymphocyte recovery syndrome and one developed intertrigo like dermatitis with stomatitis. Pegylated liposomal doxorubicin induces various skin reactions including palmoplantar erythrodysesthesia syndrome. However, the exact clinical presentation might depend on pre-existing skin diseases.

Report on the Iowa Department of Agriculture and Land Stewardship for the year ended June 30, 2007

Report on the Iowa Department of Agriculture and Land Stewardship for the year ended June 30, 2007

Current trends in illegal drug use and drug related health problems in Switzerland.

As part of the evaluation of the Confederation's measures to reduce drug related problems, a review of available data on drug use and drug related problems in Switzerland has been conducted. Source of data included: population surveys (adults and teenagers), surveys among drug users, health statistics (drug related and AIDS related deaths, HIV case reporting, drug treatments) police statistics (denunciations for consumption). The aims of reducing the number of dependent hard drug users have been achieved where heroin is concerned. In particular, there seems to have been a decrease in the number of people becoming addicted to this substance. For all other illegal substances, especially cannabis, the trend is towards an increased use, as in many European countries. As regards dependent drug users, especially injecting drug users, progress has been made in the area of harm reduction and treatment coverage. This epidemiological assessment can be used in the discussions currently engaged about the revision of the Law governing narcotics and will be a baseline for future follow up of the situation.

RAGBRAI Learn about the Land; Day 1, July 2008

Want to know what conditions to expect over the next stage of RAGBRAI? How hilly will it be, what towns and parks are between here and there, or what services are coming up in the next town?

RAGBRAI Learn about the Land; Day 2, July 2008

On today’s ride we continue riding across the Southern Iowa Drift Plain. This landform region covers over 40% of the state and comprises most of southern Iowa. Over the last several million years Iowa was subjected to at least seven glacial advances. The last of these older advances occurred approximately 500,000 years ago. Since then the landscape has been subjected to stream erosion and from12,500-24,000 years ago was mantled with a thick blanket of loess before being further eroded.

RAGBRAI Learn about the Land; Day 3, July 2008

Although during much of its geologic history Iowa was part of an interior sea, today what we see on the land surface has been heavily influenced by recent glaciation. Everything from Iowa soils, rivers, lakes, and hills has been influenced by glaciation. Most of Iowa’s bedrock is hidden beneath a thick mantle of deposits from the Cenozoic (i.e., new life) Era, spanning the last 65 million years. Geologists have divided the Cenozoic Era into two periods. These are the Tertiary (1.8-65 million years ago) and Quaternary Periods (recent to 1.8 million years ago). Most geologic records in Iowa are from the Quaternary period, and include glacial till and loess.