ELSA: An Integrated, Semi-Automated Nebular Abundance Package

We present ELSA, a new modular software package, written in C, to analyze and manage spectroscopic data from emission-line objects. In addition to calculating plasma diagnostics and abundances from nebular emission lines, the software provides a number of convenient features including the ability to ingest logs produced by IRAF's splot task, to semi-automatically merge spectra in different wavelength ranges, and to automatically generate various data tables in machine-readable or LaTeX format. ELSA features a highly sophisticated interstellar reddening correction scheme that takes into account temperature and density effects as well as He II contamination of the hydrogen Balmer lines. Abundance calculations are performed using a 5-level atom approximation with recent atomic data, based on R. Henry's ABUN program. Improvements planned in the near future include use of a three-region ionization model, similar to IRAF's nebular package, error propagation, and the addition of ultraviolet and infrared line analysis capability. Detailed documentation for all aspects of ELSA are available at http://www.williams.edu/Astronomy/research/PN .Comment: 2 pages, contributed paper, IAU Symp. 234, Planetary Nebulae in Our Galaxy and Beyon

Forced motion of a probe particle near the colloidal glass transition

We use confocal microscopy to study the motion of a magnetic bead in a dense colloidal suspension, near the colloidal glass transition volume fraction $\phi_g$. For dense liquid-like samples near $\phi_g$, below a threshold force the magnetic bead exhibits only localized caged motion. Above this force, the bead is pulled with a fluctuating velocity. The relationship between force and velocity becomes increasingly nonlinear as $\phi_g$ is approached. The threshold force and nonlinear drag force vary strongly with the volume fraction, while the velocity fluctuations do not change near the transition.Comment: 7 pages, 4 figures revised version, accepted for publication in Europhysics Letter

Three path interference using nuclear magnetic resonance: a test of the consistency of Born's rule

The Born rule is at the foundation of quantum mechanics and transforms our classical way of understanding probabilities by predicting that interference occurs between pairs of independent paths of a single object. One consequence of the Born rule is that three way (or three paths) quantum interference does not exist. In order to test the consistency of the Born rule, we examine detection probabilities in three path intereference using an ensemble of spin-1/2 quantum registers in liquid state nuclear magnetic resonance (LSNMR). As a measure of the consistency, we evaluate the ratio of three way interference to two way interference. Our experiment bounded the ratio to the order of $10^{-3} \pm 10^{-3}$, and hence it is consistent with Born's rule.Comment: 11 pages, 4 figures; Improved presentation of figures 1 and 4, changes made in section 2 to better describe the experiment, minor changes throughout, and added several reference

A First Principles Theory of Nuclear Magnetic Resonance J-Coupling in solid-state systems

A method to calculate NMR J-coupling constants from first principles in extended systems is presented. It is based on density functional theory and is formulated within a planewave-pseudopotential framework. The all-electron properties are recovered using the projector augmented wave approach. The method is validated by comparison with existing quantum chemical calculations of solution-state systems and with experimental data. The approach has been applied to verify measured J-coupling in a silicophosphate structure, Si5O(PO4)6Comment: 9 page

The remittances behaviour of the second generation in Europe: altruism or self-interest?

Whereas most research on remittances focuses on first-generation migrants, the aim of this paper is to investigate the remitting behaviour of the host country-born children of migrants - the second generation - in various European cities. Some important studies found that migrant transnationalism is not only a phenomenon for the first generation, but also apply to the second and higher generations, through, among other things, family visits, elder care, and remittances. At the same time, the maintenance of a strong ethnic identity in the ‘host’ society does not necessarily mean that second-generation migrants have strong transnational ties to their ‘home’ country. The data used in this paper is from “The Integration of the European Second Generation” (TIES) project. The survey collected information on approximately 6,250 individuals aged 18-35 with at least one migrant parent from Morocco, Turkey or former Yugoslavia, in 15 European cities, regrouped in 8 ‘countries’. For the purpose of this paper, only analyses for Austria (Linz and Vienna); Switzerland (Basle and Zurich); Germany (Berlin and Frankfurt); France (Paris and Strasbourg); the Netherlands (Amsterdam and Rotterdam); Spain (Barcelona and Madrid); and Sweden (Stockholm) will be presented.

Telecommunications systems design techniques handbook

Handbook presents design and analysis of tracking, telemetry, and command functions utilized in these systems with particular emphasis on deep-space telecommunications. Antenna requirements are also discussed. Handbook provides number of tables outlining various performance criteria. Block diagrams and performance charts are also presented

Carcinoid heart disease: Two clinical cases and a review

We present two cases of metastatic carcinoid tumours, complicated by carcinoid syndrome and by cardiac valve involvement, a well-known, but infrequent, complication. Carcinoid tumours are generally more indolent than other cancers and may have a long asymptomatic phase. The symptoms of carcinoid syndrome generally manifest only once metastases to the liver have occurred. Cardiac involvement occurs in up to 50% of patients, and heralds a poor prognosis. However, a multidisciplinary team approach has improved the prognosis and quality of life for patients with carcinoid heart disease. Therapy includes somatostatin analogues and treatment for heart failure, removal of primary or metastatic tumour deposits, valve replacement in the presence of valvular involvement, and radioisotopes therapy

Development and analysis of the Software Implemented Fault-Tolerance (SIFT) computer

SIFT (Software Implemented Fault Tolerance) is an experimental, fault-tolerant computer system designed to meet the extreme reliability requirements for safety-critical functions in advanced aircraft. Errors are masked by performing a majority voting operation over the results of identical computations, and faulty processors are removed from service by reassigning computations to the nonfaulty processors. This scheme has been implemented in a special architecture using a set of standard Bendix BDX930 processors, augmented by a special asynchronous-broadcast communication interface that provides direct, processor to processor communication among all processors. Fault isolation is accomplished in hardware; all other fault-tolerance functions, together with scheduling and synchronization are implemented exclusively by executive system software. The system reliability is predicted by a Markov model. Mathematical consistency of the system software with respect to the reliability model has been partially verified, using recently developed tools for machine-aided proof of program correctness

Protein dynamics with off-lattice Monte Carlo moves

A Monte Carlo method for dynamics simulation of all-atom protein models is introduced, to reach long times not accessible to conventional molecular dynamics. The considered degrees of freedom are the dihedrals at C$_\alpha$-atoms. Two Monte Carlo moves are used: single rotations about torsion axes, and cooperative rotations in windows of amide planes, changing the conformation globally and locally, respectively. For local moves Jacobians are used to obtain an unbiased distribution of dihedrals. A molecular dynamics energy function adapted to the protein model is employed. A polypeptide is folded into native-like structures by local but not by global moves.Comment: 10 pages, 4 Postscript figures, uses epsf.sty and a4.sty; scheduled tentatively for Phys.Rev.E issue of 1 March 199