How Pay and Benefits Change as Job Level Rises: Data from the National Compensation Survey

[Excerpt] The Bureau of Labor Statistics (BLS) National Compensation Survey (NCS) is the key source of data on the pay and benefits of workers in the United States. The NCS uses data on employer costs for a variety of compensation components to produce the Employer Cost Index (ECI) and Employer Cost of Employee Compensation (ECEC) on a quarterly basis. The ECI provides an index of changes in the employer’s cost of wages and compensation from the prior quarter and prior year. The ECEC provides estimates of wages and salaries as well as average cost of benefits per hour worked, shown in dollars and cents. On an annual basis, the NCS produces information on the availability of a suite of benefits, including health, retirement, insurance, and leave as part of the Employee Benefits Survey (EBS). This Beyond the Numbers article examines pay and benefits by job level to provide additional context to the nature of compensation among private sector workers in the United States

Current Amplification with Vertical Josephson Interferometers

It has long been recognized that a control current $I_a$ injected into the section of a two-junction superconducting quantum interference device (SQUID) is able to produce a change of its critical current $I_c$, so that a current gain $g=|dI_c/dI_a|$ can be identified. We investigate the circumstances under which large gains can be achieved by using vertical Josephson interferometers which are characterized by small loop inductances. We discuss the theory of operation of such a novel device, its performances and its advantages with respect to planar interferometers used in the previous works. Two potential applications are addressed.Comment: 18 pages, 6 figure

Disability Insurance Plans: Trends in Employee Access and Employer Costs

[Excerpt] Short- and long-term disability insurance programs replace some of the wages lost by people who cannot work because of a disabling injury or illness that is not work-related. Short-term disability insurance typically covers periods lasting less than 6 months, and long-term disability insurance lasts for the length of the disability or until retirement. Those workers who are unable to work due to injury or illness and who do not have disability insurance coverage through their employers may seek benefits from Social Security Disability Insurance (SSDI). The number of SSDI claimants has grown over the past decade as younger workers and those in relatively low- skill, low-pay jobs have applied for benefits. This has prompted interest in the amount of coverage for workers in employer-provided disability insurance programs. This issue of Beyond the Numbers examines trends in employer- provided disability insurance coverage over time, explains the basic terms of coverage for typical plans, and estimates the costs to private employers

Observational Support for the Gurzadyan-Kocharyan Relation in Clusters of Galaxies

We show that observational data for four Abell clusters of galaxies support the Gur\-za\-dyan-Kocharyan relation between the Hausdorff dimension and the dynamical properties of a galaxy system. The Hausdorff dimension is calculated using the two-point correlation function, while the dynamical parameters are estimated using available data and reasonable assumptions on the mass function of galaxies. This result can have essential consequences in the understanding of the dynamical mechanisms that determine the fractal distribution of galaxies.Comment: 5 pages, uuencoded postscript file with figures, SISSA Preprint 72/94/A, A&A Letters in pres

Morphological transformation of NGC 205?

NGC 205 is a dwarf elliptical galaxy which shows many features that are more typical of disk galaxies, and our recent study of the central stellar population has added another peculiarity. In the central regions, star formation has been on-going continuously for a few hundred Myr, until ca. 20 Myr ago, perhaps fed by gas funneled to the center in the course of morphological transformation. In this contribution we use a deep, wide-field image obtained at a scale of 2"/px to show that subtle structures can be detected in and near the body of the dwarf galaxy. The southern tidal tail can be mapped out to unprecedented distances from the center, and we suggest that the northern tail is partially hidden behind a very extended dust lane, or ring, belonging to M31. A spiral pattern emerges across the body of the galaxy, but it might be explained by another M31 dust filament.Comment: 2 pages, 1 figure, poster contributed to IAU Symposium 262, Stellar Populations -- Planning for the Next Decade, G. Bruzual & S. Charlot, ed

Topological invariants of eigenvalue intersections and decrease of Wannier functions in graphene

We investigate the asymptotic decrease of the Wannier functions for the valence and conduction band of graphene, both in the monolayer and the multilayer case. Since the decrease of the Wannier functions is characterised by the structure of the Bloch eigenspaces around the Dirac points, we introduce a geometric invariant of the family of eigenspaces, baptised eigenspace vorticity. We compare it with the pseudospin winding number. For every value $n \in Z$ of the eigenspace vorticity, we exhibit a canonical model for the local topology of the eigenspaces. With the help of these canonical models, we show that the single band Wannier function $w$ satisfies $|w(x)| \leq \mathrm{const} |x|^{- 2}$ as $|x| \rightarrow \infty$, both in monolayer and bilayer graphene.Comment: 54 pages, 4 figures. Version 2: Section 1.0 added; improved results on the decay rate of Wannier functions in graphene (Th. 4.3 and Prop. 4.6). Version 3: final version, to appear in JSP. New in V3: previous Sections 3.1 and 3.2 are now Section 2.2; Lemma 2.4 modified (previous statement was not correct); major modifications to Section 2.3; Assumption 4.1(v) on the Hamiltonian change

A study of relative velocity statistics in Lagrangian perturbation theory with PINOCCHIO

Subject of this paper is a detailed analysis of the PINOCCHIO algorithm for studying the relative velocity statistics of merging haloes in Lagrangian perturbation theory. Given a cosmological background model, a power spectrum of fluctuations as well as a Gaussian linear density contrast field $\delta_{\rm l}$ is generated on a cubic grid, which is then smoothed repeatedly with Gaussian filters. For each Lagrangian particle at position \bmath{q} and each smoothing radius $R$, the collapse time, the velocities and ellipsoidal truncation are computed using Lagrangian Perturbation Theory. The collapsed medium is then fragmented into isolated objects by an algorithm designed to mimic the accretion and merger events of hierarchical collapse. Directly after the fragmentation process the mass function, merger histories of haloes and the statistics of the relative velocities at merging are evaluated. We reimplemented the algorithm in C++, recovered the mass function and optimised the construction of halo merging histories. Comparing our results with the output of the Millennium simulation suggests that PINOCCHIO is well suited for studying relative velocities of merging haloes and is able to reproduce the pairwise velocity distribution.Comment: 10 pages, 8 figure

Symmetry and localization in periodic crystals: triviality of Bloch bundles with a fermionic time-reversal symmetry

We describe some applications of group- and bundle-theoretic methods in solid state physics, showing how symmetries lead to a proof of the localization of electrons in gapped crystalline solids, as e.g. insulators and semiconductors. We shortly review the Bloch-Floquet decomposition of periodic operators, and the related concepts of Bloch frames and composite Wannier functions. We show that the latter are almost-exponentially localized if and only if there exists a smooth periodic Bloch frame, and that the obstruction to the latter condition is the triviality of a Hermitian vector bundle, called the Bloch bundle. The role of additional $\mathbb{Z}_2$-symmetries, as time-reversal and space-reflection symmetry, is discussed, showing how time-reversal symmetry implies the triviality of the Bloch bundle, both in the bosonic and in the fermionic case. Moreover, the same $\mathbb{Z}_2$-symmetry allows to define a finer notion of isomorphism and, consequently, to define new topological invariants, which agree with the indices introduced by Fu, Kane and Mele in the context of topological insulators.Comment: Contribution to the proceedings of the conference "SPT2014 - Symmetry and Perturbation Theory", Cala Gonone, Italy (2014). Keywords: Periodic Schr\"{o}dinger operators, composite Wannier functions, Bloch bundle, Bloch frames, time-reversal symmetry, space-reflection symmetry, invariants of topological insulator