Provenance Circuits for Trees and Treelike Instances (Extended Version)

Query evaluation in monadic second-order logic (MSO) is tractable on trees and treelike instances, even though it is hard for arbitrary instances. This tractability result has been extended to several tasks related to query evaluation, such as counting query results [3] or performing query evaluation on probabilistic trees [10]. These are two examples of the more general problem of computing augmented query output, that is referred to as provenance. This article presents a provenance framework for trees and treelike instances, by describing a linear-time construction of a circuit provenance representation for MSO queries. We show how this provenance can be connected to the usual definitions of semiring provenance on relational instances [20], even though we compute it in an unusual way, using tree automata; we do so via intrinsic definitions of provenance for general semirings, independent of the operational details of query evaluation. We show applications of this provenance to capture existing counting and probabilistic results on trees and treelike instances, and give novel consequences for probability evaluation.Comment: 48 pages. Presented at ICALP'1

The Pros and Cons of Sick Pay Schemes: A Method to Test for Contagious Presenteeism and Shirking Behavior

This paper proposes a test for the existence and the degree of contagious presenteeism and negative externalities in sickness insurance schemes. First, we theoretically decompose moral hazard into shirking and contagious presenteeism behavior. Then we derive testable conditions for reduced shirking, increased presenteeism, and the level of overall moral hazard when benefits are cut. We implement the test empirically exploiting German sick pay reforms and administrative industry-level data on certified sick leave by diagnoses. The labor supply adjustment for contagious diseases is significantly smaller than for non-contagious diseases, providing evidence for contagious presenteeism and negative externalities which arise in form of infections

Labor Market Effects of US Sick Pay Mandates

This paper exploits temporal and spatial variation in the implementation of US sick pay mandates to assess their labor market consequences. We use the Synthetic Control Group Method (SCGM) and the Quarterly Census of Employment and Wages (QCEW) to estimate the causal effect of mandated sick leave on employment and wages. Our findings do not provide much evidence that employment or wages were significantly affected by the mandates which typically allow employees to earn one hour of paid sick leave per work week, up to seven days per year. Joint tests for all treatment regions let us exclude, with 90% statistical probability, that wages decreased by more than 1% as a result of the mandates. With 92% probability, we can exclude that employment decreased by more than 1%

The Pros and Cons of Sick Pay Schemes: A Method to Test for Contagious Presenteeism and Shirking Behavior

This paper proposes a test for the existence and the degree of contagious presenteeism and negative externalities in sickness insurance schemes. First, we theoretically decompose moral hazard into shirking and contagious presenteeism behavior. Then we derive testable conditions for reduced shirking, increased presenteeism, and the level of overall moral hazard when benefits are cut. We implement the test empirically exploiting German sick pay reforms and administrative industry-level data on certified sick leave by diagnoses. The labor supply adjustment for contagious diseases is significantly smaller than for non-contagious diseases, providing evidence for contagious presenteeism and negative externalities which arise in form of infections

Answer Set Solving with Bounded Treewidth Revisited

Parameterized algorithms are a way to solve hard problems more efficiently, given that a specific parameter of the input is small. In this paper, we apply this idea to the field of answer set programming (ASP). To this end, we propose two kinds of graph representations of programs to exploit their treewidth as a parameter. Treewidth roughly measures to which extent the internal structure of a program resembles a tree. Our main contribution is the design of parameterized dynamic programming algorithms, which run in linear time if the treewidth and weights of the given program are bounded. Compared to previous work, our algorithms handle the full syntax of ASP. Finally, we report on an empirical evaluation that shows good runtime behaviour for benchmark instances of low treewidth, especially for counting answer sets.Comment: This paper extends and updates a paper that has been presented on the workshop TAASP'16 (arXiv:1612.07601). We provide a higher detail level, full proofs and more example

Labor Market Effects of U.S. Sick Pay Mandates

This paper exploits temporal and spatial variation in the implementation of nine-city- and four state-level U.S. sick pay mandates to assess their labor market consequences. We use the synthetic control group method and traditional difference-in-differences models along with the Quarterly Census of Employment and Wages to estimate the causal effects of mandated sick pay on employment and wages. We do not find much evidence that employment or wages were significantly affected by the mandates that typically allow employees to earn one hour of paid sick leave per work week, up to seven days per year. Employment decreases of 2 percent lie outside the 92 percent confidence interval and wage decreases of 3 percent lie outside the 95 percent confidence interval

Triplet-singlet conversion in ultracold Cs2_2 and production of ground state molecules

We propose a process to convert ultracold metastable Cs$_2$ molecules in their lowest triplet state into (singlet) ground state molecules in their lowest vibrational levels. Molecules are first pumped into an excited triplet state, and the triplet-singlet conversion is facilitated by a two-step spontaneous decay through the coupled $A^{1}\Sigma_{u}^{+} \sim b ^{3}\Pi_{u}$ states. Using spectroscopic data and accurate quantum chemistry calculations for Cs$_2$ potential curves and transition dipole moments, we show that this process has a high rate and competes favorably with the single-photon decay back to the lowest triplet state. In addition, we demonstrate that this conversion process represents a loss channel for vibrational cooling of metastable triplet molecules, preventing an efficient optical pumping cycle down to low vibrational levels