Computational aspects of DNA mixture analysis

Statistical analysis of DNA mixtures is known to pose computational challenges due to the enormous state space of possible DNA profiles. We propose a Bayesian network representation for genotypes, allowing computations to be performed locally involving only a few alleles at each step. In addition, we describe a general method for computing the expectation of a product of discrete random variables using auxiliary variables and probability propagation in a Bayesian network, which in combination with the genotype network allows efficient computation of the likelihood function and various other quantities relevant to the inference. Lastly, we introduce a set of diagnostic tools for assessing the adequacy of the model for describing a particular dataset

Regulating water extraction in a river basin with upstream-downstream communities

This paper proposes a tax mechanism modelled for water extraction in a river system with upstream and downstream farmers. The tax mechanism is based on the regulator’s own estimation of aggregate extraction and for that reason the tax addresses the problem of asymmetric information. It is demonstrated that the tax mechanism ensures approximately correct marginal extraction incentives for the individual farmer. Consequently, it is concluded that the tax mechanism proposed here has a practical application.Water extraction; River system; Tax mechanism; Upstream-downstream users

How a Mandatory Activation Program Reduces Unemployment Durations: The Effects of Distance

In an experimental setting some Danish unemployed workers were assigned to an activation program while others were not. Unemployed who were assigned to the activation program found a job more quickly. We show that the activation effect increases with the distance between the place of residence of the unemployed worker and the place where the activation took place. We also find that the quality of the post-unemployment jobs was not affected by the activation program. Both findings confirm that activation programs mainly work because they are compulsory and unemployed don’t like them.Unemployment insurance;unemployment duration;experiment;activation programs

Overtime work, dual job holding and taxation

Traditionally, labour supply data do not include much information on hours and wages in secondary job or overtime work. In this paper, we estimate labour supply models based on survey information on hours and wages in overtime work and second job which is merged to detailed register information on income taxes, deductions, taxable income etc. We also allow for the effect of observed fixed costs in main occupation and unobserved fixed costs in second job, and a ‘stigmatization effect’ from unemployment. The estimated models follow a ‘Hausman-approach’. The results indicate that the labour supply elasticities are highly sensitive to the inclusion of information on overtime work and secondary job and to the handling of fixed costs of work. The estimated elasticities are numerically larger when explicit information on overtime and second job work is taken into account compared to traditional labour supply models without explicit information on overtime pay and second job wages. However, when the model allows for stigmatization effects and unobserved fixed costs of work in second job, the resulting elasticities reduce considerably.Labour supply; Dual job holding; Overtime work; Piecewise linear budget constraints

How a Mandatory Activation Program Reduces Unemployment Durations: The Effects of Distance

In an experimental setting some Danish unemployed workers were assigned to an activation program while others were not. Unemployed who were assigned to the activation program found a job more quickly. We show that the activation effect increases with the distance between the place of residence of the unemployed worker and the place where the activation took place. We also find that the quality of the post-unemployment jobs was not affected by the activation program. Both findings confirm that activation programs mainly work because they are compulsory and unemployed don't like them.unemployment insurance, unemployment duration, experiment, activation programs

ORGANIC FARMING IN DENMARK-PRODUCTIVITY, TECHNICAL CHANGE AND MARKET EXIT

This paper attempts to quantitatively measure the change in the productivity of Danish organic farming in recent years. Based on a translog production frontier framework the technical and scale efficiency on farm level is analysed by following a time trends as well as a general index model specification. We further try to analyse the significance of subsidies for promoting long term growth in organic production by estimating a bootstrapped bivariate probit model with respect to factors influencing the probability of organic market exit. The results revealed significant differencies in the organic farms' technical efficiencies, no significant total factor productivity growth and even a slightly negative rate of technical change in the period investigated. We found evidence for a positive relationship between subsidy payments and an increase in farm efficiency, technology improvements and a decreasing probability of organic market exit which was also confirmed for off farm income.Organic Farming, Total Factor Productivity, Market Exit, Agribusiness, Productivity Analysis,

Relational Contracting and Allocation of Decision Rights in the Agri-Food Industry: Producer Contracts and Food Safety

We apply a formal theoretical model of adaptation to two empirical settings within the agri-food industry: specialized pig production and food safety in Denmark. The objective is to allocate decision rights ex ante so that actual decisions taken ex post will optimize the profit accruing to the two parties in a contractual or integrative relation. Two applications are presented in this paper: First an actual partnership between two pork producers in Denmark. Based on detailed budgets we develop detailed schedules for the “reneging temptations” of the two partners- These are the temptations to renege on the contract during the evolution of the partnership. Using a model developed by Baker, Gibbons and Murphy (2006) we calculate equilibria using the Folk theorem in order to determine which is the best allocation of decision rights. We find that the existing allocation of decision rights in the case we examine is efficient in the sense that it results into a second best allocation. Using the same modelling approach we present a second application on salmonella control related to end-feeding, that is, salmonella contamination of pork due to filled bellies of pigs fed for the last 12 hours before delivery. Based on appropriate assumptions, the parties should give the decision right (whether to end-feed or not) to the slaughterhouse in order to reach the firstbest solution which, given the assumptions, is feasibleTheory of the firm, Adaptation theory, Contracts, Decision Rights, Pig production, Food safety, Agribusiness, Agricultural and Food Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Industrial Organization, D21, L2, Q1,