High wage workers and low wage firms : negative assortative matching or statistical artefact?

In the empirical literature on the estimation of firm and worker heterogeneity using linked employer-employee data, unobserved worker quality appears to be negatively correlated with unobserved firm quality. We investigate the possibility that this is simply caused by standard estimation error and develop formulae that show that the estimated correlation is biased downwards if there is true positive assortative matching and when any conditioning covariates are uncorrelated with the firm and worker fixed effects. This result applies to any two-way (or higher) error-components model estimated by fixed-effects methods. We apply these bias corrections to a large German linked employer-employee dataset. We find that although the biases can be considerable, they are not sufficiently large to remove the negative correlation entirely. -- Auf der Basis von zusammengefügten Betriebs- und Personendaten findet sich in der empirischen Literatur eine negative Korrelation zwischen den unbeobachteten Eigenschaften von Beschäftigten und denen von Betrieben. Wir zeigen formal, dass die geschätzte Korrelation nach unten verzerrt ist, sofern ein positives Matching existiert und sofern die übrigen Kovariate mit den Betriebs- und Beschäftigten Fixed Effects unkorreliert sind. Dieses Ergebnis kann allgemein auf jedes mehrdimensionale Fixed Effects Modell übertragen werden. Für kombinierte Firmen-Beschäftigtendaten aus Deutschland finden wir eine beträchtliche Verzerrung in der geschätzten Korrelation. Diese ist jedoch nicht groß genug, um die ermittelte negative Korrelation vollständig erklären zu können.linked employee-employer panel data,biases,fixed-effects

A geometric proof of the Kochen-Specker no-go theorem

We give a short geometric proof of the Kochen-Specker no-go theorem for non-contextual hidden variables models. Note added to this version: I understand from Jan-Aake Larsson that the construction we give here actually contains the original Kochen-Specker construction as well as many others (Bell, Conway and Kochen, Schuette, perhaps also Peres).Comment: This paper appeared some years ago, before the author was aware of quant-ph. It is relevant to recent developments concerning Kochen-Specker theorem

Optimal Bell tests do not require maximally entangled states

Any Bell test consists of a sequence of measurements on a quantum state in space-like separated regions. Thus, a state is better than others for a Bell test when, for the optimal measurements and the same number of trials, the probability of existence of a local model for the observed outcomes is smaller. The maximization over states and measurements defines the optimal nonlocality proof. Numerical results show that the required optimal state does not have to be maximally entangled.Comment: 1 figure, REVTEX

A proof of Bell\u27s inequality in quantum mechanics using causal interactions

We give a simple proof of Bell\u27s inequality in quantum mechanics which, in conjunction with experiments, demonstrates that the local hidden variables assumption is false. The proof sheds light on relationships between the notion of causal interaction and interference between particles

Site selective reading of epigenetic markers by a dual-mode synthetic receptor array.

Variably functionalized self-folding deep cavitands form an arrayed, fluorescent indicator displacement assay system for the detection of post-translationally modified (PTM) histone peptides. The hosts bind trimethyllysine (KMe3) groups, and use secondary upper rim interactions to provide more sensitive discrimination between targets with identical KMe3 binding handles. The sensor array uses multiple different recognition modes to distinguish between miniscule differences in target, such as identical lysine modifications at different sites of histone peptides. In addition, the sensor is affected by global changes in structure, so it is capable of discriminating between identical PTMs, at identical positions on amino acid fragments that vary only in peptide backbone length, and can be applied to detect non-methylation modifications such as acetylation and phosphorylations located multiple residues away from the targeted binding site. The synergistic application of multiple variables allows dual-mode deep cavitands to approach levels of recognition selectivity usually only seen with antibodies

Maximal violation of the CGLMP inequality for infinite dimensional states

We present a much simplified version of the CGLMP inequality for the 2 x 2 x d Bell scenario. Numerical maximization of the violation of this inequality over all states and measurements suggests that the optimal state is far from maximally entangled, while the best measurements are the same as conjectured best measurements for the maximally entangled state. For very large values of d the inequality seems to reach its minimal value given by the probability constraints. This gives numerical evidence for a tight quantum Bell inequality (or generalized Csirelson inequality) for the 2 x 2 x inf scenario.Comment: Introduction shortened, small changes, including new results for dimension of Hilbert space bigger than number of outcomes; 4 pages, 2 figure

High wage workers and low wage firms : negative assortative matching or statistical artefact?

In the empirical literature on the estimation of firm and worker heterogeneity using linked employer-employee data, unobserved worker quality appears to be negatively correlated with unobserved firm quality. We investigate the possibility that this is simply caused by standard estimation error and develop formulae that show that the estimated correlation is biased downwards if there is true positive assortative matching and when any conditioning covariates are uncorrelated with the firm and worker fixed effects. This result applies to any two-way (or higher) error-components model estimated by fixed-effects methods. We apply these bias corrections to a large German linked employer-employee dataset. We find that although the biases can be considerable, they are not sufficiently large to remove the negative correlation entirely.Auf der Basis von zusammengefügten Betriebs- und Personendaten findet sich in der empirischen Literatur eine negative Korrelation zwischen den unbeobachteten Eigenschaften von Beschäftigten und denen von Betrieben. Wir zeigen formal, dass die geschätzte Korrelation nach unten verzerrt ist, sofern ein positives Matching existiert und sofern die übrigen Kovariate mit den Betriebs- und Beschäftigten Fixed Effects unkorreliert sind. Dieses Ergebnis kann allgemein auf jedes mehrdimensionale Fixed Effects Modell übertragen werden. Für kombinierte Firmen-Beschäftigtendaten aus Deutschland finden wir eine beträchtliche Verzerrung in der geschätzten Korrelation. Diese ist jedoch nicht groß genug, um die ermittelte negative Korrelation vollständig erklären zu können

Contracting Out: A Study of the Honduran Experience

This study was conducted by the National Association of Schools of Public Affairs and Administration (NASPAA) at the request of USAID/Honduras under the terms of NASPAA\u27s Technical Cooperative Agreement with USAID. The study examined the experiences of USAID/Honduras and the Government of Honduras with the contracting out of construction activities in three sectors. The purpose of the study was to document empirical evidence regarding the performance of contracting out as a policy measure to increase private sector initiatives in Honduras

Delaware Physicians\u27 Behavior Regarding Patient Advice on Tobacco Use

No abstract available

Salt Links Dominate Affinity of Antibody HyHEL-5 for Lysozyme through Enthalpic Contributions*

The binding of murine monoclonal antibody HyHEL-5 to lysozyme has been the subject of extensive crystallographic, computational, and experimental investigations. The complex of HyHEL-5 with hen egg lysozyme (HEL) features salt bridges between Fab heavy chain residue Glu50, and Arg45 and Arg68 of HEL. This interaction has been predicted to play a dominant role in the association on the basis of molecular electrostatics calculations. The association of aspartic acid and glutamine mutants at position 50H of the cloned HyHEL-5 Fab with HEL and bobwhite quail lysozyme (BQL), an avian variant bearing an Arg68 ? Lys substitution in the epitope, was characterized by isothermal titration calorimetry and sedimentation equilibrium. Affinities for HEL were reduced by 400-fold (E50HD) and 40,000-fold (E50HQ) (??G� estimated at 4.0 and 6.4 kcal mol?1, respectively). The same mutations reduce affinity for BQL by only 7- and 55-fold, respectively, indicating a reduced specificity for HEL. The loss of affinity upon mutation is in each case primarily due to an unfavorable change in the enthalpy of the interaction; the entropic contribution is virtually unchanged. An enthalpy-entropy compensation exists for each interaction; ?H� decreases, while ?S� increases with temperature. The ?Cp for each mutant interaction is less negative than the wild-type. Mutant-cycle analysis suggests the mutations present in the HyHEL-5 Fab mutants are linked to those present in the BQL with coupling energies between 3 and 4 kcal mol?1