The Bounded Storage Model in The Presence of a Quantum Adversary

An extractor is a function E that is used to extract randomness. Given an imperfect random source X and a uniform seed Y, the output E(X,Y) is close to uniform. We study properties of such functions in the presence of prior quantum information about X, with a particular focus on cryptographic applications. We prove that certain extractors are suitable for key expansion in the bounded storage model where the adversary has a limited amount of quantum memory. For extractors with one-bit output we show that the extracted bit is essentially equally secure as in the case where the adversary has classical resources. We prove the security of certain constructions that output multiple bits in the bounded storage model.Comment: 13 pages Latex, v3: discussion of independent randomizers adde

Graph transformation systems, Petri nets and Semilinear Sets: Checking for the Absence of Forbidden Paths in Graphs

We introduce an analysis method that checks for the absence of (Euler) paths or cycles in the set of graphs reachable from a start graph via graph transformation rules. This technique is based on the approximation of graph transformation systems by Petri nets and on semilinear sets of markings. An important application is deadlock analysis in distributed systems

Parent Resource Packet - A Guide for New Parents

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Reservation wages and the wage flexibility puzzle

Wages are only mildly cyclical, implying that shocks to labour demand have a larger short-run impact on unemployment rather than wages, at odds with the quantitative predictions of the canonical search and matching model. This paper provides an alternative perspective on the wage flexibility puzzle, explaining why the canonical model can only match the observed cyclicality of wages if the replacement ratio is implausibly high. We show that this failure remains even if wages are only occasionally renegotiated, unless the persistence in unemployment is implausibly low. We then provide some evidence that part of the problem comes from the implicit model for the determination of reservation wages. Estimates for the UK and West Germany provide evidence that reservation wages are much less cyclical than predicted even conditional on the observed level of wage cyclicality. We present evidence that elements of perceived “fairness” or “reference points” in reservation wages may address this model failure

Reservation wages and the wage flexibility puzzle

Wages are only mildly cyclical, implying that shocks to labour demand have a larger short-run impact on unemployment rather than wages, at odds with the quantitative predictions of the canonical search model – even if wages are only occasionally renegotiated. We argue that one source of the wage flexibility puzzles is plausibly the model for the determination of reservation wages, and consider an alternative reservation wage model based on reference dependence in job search. This extension generates less cyclical reservation wages than the canonical model, as long as reference points are less cyclical than forward-looking components of reservation wages such as the arrival rate of job offers. We provide evidence that reservation wages significantly respond to backward looking reference points, as proxied by rents earned in previous jobs. In a model calibration we show that backward-looking reference dependence markedly reduces the predicted cyclicality of both wages and reservation wages and can reconcile theoretical predictions of the canonical model with the observed cyclicality of wages and reservation wages

Reservation wages and the wage flexibility puzzle

Using micro data for the UK and Germany, we provide novel evidence on the cyclical properties of reservation wages and estimate that wages and reservation wages are characterised by moderate and very similar degrees of cyclicality. Several job search models that quantitatively match the cyclicality of wages tend to overpredict the cyclicality in reservation wages. We show that this puzzle can be addressed when reservation wages display backward-looking reference dependence. Model calibrations that allow for reference dependence match the empirically observed cyclicality of wages and reservation wages for plausible value of all other model parameters

Long-term balancing selection drives evolution of immunity genes in Capsella.

Genetic drift is expected to remove polymorphism from populations over long periods of time, with the rate of polymorphism loss being accelerated when species experience strong reductions in population size. Adaptive forces that maintain genetic variation in populations, or balancing selection, might counteract this process. To understand the extent to which natural selection can drive the retention of genetic diversity, we document genomic variability after two parallel species-wide bottlenecks in the genus Capsella. We find that ancestral variation preferentially persists at immunity related loci, and that the same collection of alleles has been maintained in different lineages that have been separated for several million years. By reconstructing the evolution of the disease-related locus MLO2b, we find that divergence between ancient haplotypes can be obscured by referenced based re-sequencing methods, and that trans-specific alleles can encode substantially diverged protein sequences. Our data point to long-term balancing selection as an important factor shaping the genetics of immune systems in plants and as the predominant driver of genomic variability after a population bottleneck

Can helping the sick hurt the able? Incentives, information and disruption in a welfare reform

The UK Jobcentre Plus reform sharpened bureaucratic incentives to help disability benefit recipients (relative to unemployment insurance recipients) into jobs. In the long run, the policy raised exits off diasability benefits by 10% and left unemployment outflows roughly unchanged, consistent with (i) beneficial effects of reorganising welfare offices for both groups, and (ii) a shift in bureaucrats' efforts towards getting disability benefit recipients into jobs relative to those on unemployment benefit. The policy accounted for about 30% of the decline in the aggregate disability rolls between 2003 and 2008. In the short run, however, we detect a reduction in unemployment exits and no effect on disability exits, suggesting important initial disruption effects from the big reorganisation. This highlights the difficulty of welfare reform as policymakers may focus on the short-run political costs rather than the long-run economic benefits

Light particle spectra from 35 MeV/nucleon 12C-induced reactions on 197Au

Energy spectra for p, d, t, 3He, 4He, and 6He from the reaction 12C+197Au at 35 MeV/nucleon are presented. A common intermediate rapidity source is identified using a moving source fit to the spectra that yields cross sections which are compared to analogous data at other bombarding energies and to several different models. The excitation function of the composite to proton ratios is compared with quantum statistical, hydrodynamic, and thermal models