Disjunct Lake Michigan Populations of Two Atlantic Coast Spiders, \u3ci\u3eDisembolus Bairdi\u3c/i\u3e and \u3ci\u3eGrammonota Pallipes\u3c/i\u3e (Araneae: Linyphiidae)

Two species of linyphiid spiders, Disembolus bairdi Edwards, 1999 and Grammonota pallipes Banks, 1895, were discovered along the southwestern coast of Lake Michigan in Lake County, Illinois representing an Atlantic Coastal Plain disjunct distribution. A brief discussion of known collection sites, habitat preferences, and possible modes of dispersal are given

The Anderson impurity model with a narrow-band host: from orbital physics to the Kondo effect

A particle-hole symmetric Anderson impurity model with a metallic host of narrow bandwidth is studied within the framework of the local moment approach. The resultant single-particle spectra are compared to unrestricted Hartree-Fock, second order perturbation theory about the noninteracting limit, and Lanczos spectra by Hofstetter and Kehrein. Rather accurate analytical results explain the spectral evolution over almost the entire range of interactions. These encompass, in particular, a rationale for the four-peak structure observed in the low-energy sector of the Lanczos spectra in the moderate-coupling regime. In weak coupling, the spectral evolution is governed by orbital effects, while in the strong coupling Kondo limit, the model is shown to connect smoothly to the generic Anderson impurity with a flat and infinitely wide hybridization band.Comment: 17 pages, 7 figure

Work Hours Constraints: Impacts and Policy Implications

If individuals reveal their preference as consumers, then they are taken seriously. What happens if individuals, as employees, reveal their preferences in working hours? And what happens if there is a misalignment between actual hours worked and preferred hours, the so-called work hours constraints? How does this affect the productivity of workers, their health, and overall life satisfaction? Labor supply and corresponding demand are fundamental to production. Labor economists know for long that the fit of a worker in a job and the matching of skills to the assigned employment are of paramount importance; they guarantee high productivity, quality output, and individual happiness. Employees demand higher social awareness and a working environment where they feel useful and happy. The evidence shows that discrepancies between preferred hours of work and actual hours of work can have serious detrimental effects on workers, perverse effects on labor supply with unintended direct ramifications on the labor market and indirect implications on the goods and services markets. The sooner employers acknowledge and address working hours constraints the faster we can build work lives that make us better off.labor market, work time, work hours constraints, health, happiness, satisfaction

Unions and Managerial Pay

Unions compress the wage distribution among workers covered by union contracts. We ask whether unions also have an effect on the managers of unionized firms. To this end we collected and assembled data on unionization and managerial pay within firms and industries in the U.S. and across countries. Generally, we find a negative correlation between executive compensation and unionization in our cross-section data, but no relationship of changes in unionization on the growth of compensation of executives over time. Using NLRB elections data, we find that a loss of union members due to decertification elections is associated with higher CEO pay, although our estimates are imprecise. With CPS data we consistently find that where unions are stronger, fewer managers are employed

Lithium abundance and 6Li/7Li ratio in the active giant HD123351 I. A comparative analysis of 3D and 1D NLTE line-profile fits

Current three-dimensional (3D) hydrodynamical model atmospheres together with NLTE spectrum synthesis, permit to derive reliable atomic and isotopic chemical abundances from high-resolution stellar spectra. Not much is known about the presence of the fragile 6Li isotope in evolved solar-metallicity RGB stars, not to mention its production in magnetically active targets like HD123351. From fits of the observed CFHT spectrum with synthetic line profiles based on 1D and 3D model atmospheres, we seek to estimate the abundance of the 6Li isotope and to place constraints on its origin. We derive A(Li) and the 6Li/7Li isotopic ratio by fitting different synthetic spectra to the Li-line region of a high-resolution CFHT spectrum (R=120 000, S/R=400). The synthetic spectra are computed with four different line lists, using in parallel 3D hydrodynamical CO5BOLD and 1D LHD model atmospheres and treating the line formation of the lithium components in non-LTE (NLTE). We find A(Li)=1.69+/-0.11 dex and 6Li/7Li=8.0+/-4.4 % in 3D-NLTE, using the line list of Mel\'endez et al. (2012), updated with new atomic data for V I, which results in the best fit of the lithium line profile of HD123351. Two other line lists lead to similar results but with inferior fit qualities. Our 2-sigma detection of the 6Li isotope is the result of a careful statistical analysis and the visual inspection of each achieved fit. Since the presence of a significant amount of 6Li in the atmosphere of a cool evolved star is not expected in the framework of standard stellar evolution theory, non-standard, external lithium production mechanisms, possibly related to stellar activity or a recent accretion of rocky material, need to be invoked to explain the detection of 6Li in HD123351.Comment: 16 pages, 11 figures. Accepted for publication in A&

Constraints on Gravitino Dark Matter Scenarios with Long-Lived Charged Sleptons

Considering scenarios in which the gravitino is the lightest supersymmetric particle and a charged slepton the next-to-lightest supersymmetric particle (NLSP), we discuss cosmological constraints on the masses of the gravitino and the NLSP slepton. The presented mass bounds are crucial for gravitino dark matter studies and potential gravitino signatures at future colliders

Activity and Diversity of Collembola (Insecta) and Mites (Acari) in Litter of a Degraded Midwestern Oak Woodland

Litter-inhabiting Collembola and mites were sampled using pitfall traps over a twelve-month period from four sub-communities within a 100-acre (40-ha) oak-woodland complex in northern Cook County, Illinois. Sampled locations included four areas where future ecological restoration was planned (mesic woodland, dry-mesic woodland, mesic upland forest, and buckthorn-dominated savanna) and a mesic woodland control that would not be restored. Fifty-eight mite and 30 Collembola taxa were identified out of 5,308 and 190,402 individuals trapped, respectively. There was a significant positive relationship between litter mass and both mite diversity and the ratio of Oribatida to Prostigmata and a significant negative relationship between Collembola diversity and litter. Based on multivariate analysis, Collembola and mite composition differed by sub-community and season interaction

Quantum Phase Transition of Ground-state Entanglement in a Heisenberg Spin Chain Simulated in an NMR Quantum Computer

Using an NMR quantum computer, we experimentally simulate the quantum phase transition of a Heisenberg spin chain. The Hamiltonian is generated by a multiple pulse sequence, the nuclear spin system is prepared in its (pseudo-pure) ground state and the effective Hamiltonian varied in such a way that the Heisenberg chain is taken from a product state to an entangled state and finally to a different product state.Comment: 5 pages, 5 eps figures. Accepted in Phys. Rev.