Chemical and Toxicological Analyses of Lake Calumet (Cook County, Illinois) Sediments

HWRIC Project 88-048NTIS PB90-16072

Quantum Walks with Entangled Coins

We present a mathematical formalism for the description of unrestricted quantum walks with entangled coins and one walker. The numerical behaviour of such walks is examined when using a Bell state as the initial coin state, two different coin operators, two different shift operators, and one walker. We compare and contrast the performance of these quantum walks with that of a classical random walk consisting of one walker and two maximally correlated coins as well as quantum walks with coins sharing different degrees of entanglement. We illustrate that the behaviour of our walk with entangled coins can be very different in comparison to the usual quantum walk with a single coin. We also demonstrate that simply by changing the shift operator, we can generate widely different distributions. We also compare the behaviour of quantum walks with maximally entangled coins with that of quantum walks with non-entangled coins. Finally, we show that the use of different shift operators on 2 and 3 qubit coins leads to different position probability distributions in 1 and 2 dimensional graphs.Comment: Two new sections and several changes from referees' comments. 12 pages and 12 (colour) figure

Intraocular pressure reduction and regulation system

An intraocular pressure reduction and regulation system is described and data are presented covering performance in: (1) reducing intraocular pressure to a preselected value, (2) maintaining a set minimum intraocular pressure, and (3) reducing the dynamic increases in intraocular pressure resulting from external loads applied to the eye

Mass fractionation of the lunar surface by solar wind sputtering

The sputtering of the lunar surface by the solar wind is examined as a possible mechanism of mass fractionation. Simple arguments based on current theories of sputtering and the ballistics of the sputtered atoms suggest that most ejected atoms will have sufficiently high energy to escape lunar gravity. However, the fraction of atoms which falls back to the surface is enriched in the heavier atomic components relative to the lighter ones. This material is incorporated into the heavily radiation-damaged outer surfaces of grains where it is subject to resputtering. Over the course of several hundred years an equilibrium surface layer, enriched in heavier atoms, is found to form. The dependence of the calculated results upon the sputtering rate and on the details of the energy spectrum of sputtered particles is investigated. It is concluded that mass fractionation by solar wind sputtering is likely to be an important phenomenon on the lunar surface

Stochastic Gene Expression in a Lentiviral Positive Feedback Loop: HIV-1 Tat Fluctuations Drive Phenotypic Diversity

Stochastic gene expression has been implicated in a variety of cellular processes, including cell differentiation and disease. In this issue of Cell, Weinberger et al. (2005) take an integrated computational-experimental approach to study the Tat transactivation feedback loop in HIV-1 and show that fluctuations in a key regulator, Tat, can result in a phenotypic bifurcation. This phenomenon is observed in an isogenic population where individual cells display two distinct expression states corresponding to latent and productive infection by HIV-1. These findings demonstrate the importance of stochastic gene expression in molecular "decision-making."Comment: Supplemental data available as q-bio.MN/060800

Chinese MBA Student Attitudes and Perceptions as They Relate to Personal Selling

In the United States entry-level sales positions are often filled by graduates from universities and colleges. However, a challenge faced by recruiters seeking these college graduates to fill sales positions has been that many college graduates have a negative perception of the role of the salesperson in today’s economy. Thus, many businesses discover that they have to overcome the biases and stereotypes held by students as they attempt to recruit exceptional individuals into sales positions. Given the growth and size of the Chinese economy, it seems that determining how Chinese students perceive the role of sales and their attitudes toward sales careers could be significant to both businesses and academics. Based on this perception a survey designed to assess the attitudes toward personal selling was administered to 182 Chinese MBA students enrolled in graduate courses conducted in the US. The findings indicate that many of the attitudes possessed by Chinese students in terms of both the positive and negative attitudes toward sales generally reflect attitudes found in studies in other nations. The research concludes with recommendations for future studies and conclusions relevant to organizations recruiting salespeople and universities that are involved in educational activities

Survey of the vertebrate fauna of the Dotswood area, North Queensland

The results of a survey of mammals, birds, reptiles, amphibians and fish of the Dotswood area west of Townsville are presented. Habitats included in the survey were woodland, open forest, tall open forest, closed forest (rainforest), riparian forest and rocky outcrops. A total of 297 species of vertebrates were observed using a variety of survey techniques including live trapping, pit trapping, observational transects, mist netting and spotlighting. Exact locations of observation and indices of relative abundance of each species are included

Precise location of Sagittarius X ray sources with a rocket-borne rotating modulation collimator

Precise location of Sagittarius X ray sources with rocket-borne rotating modulation collimato

Hierarchical Control for Trajectory Generation and Tracking Via Active Front Steering

A new hierarchical model predictive controller for autonomous vehicle steering control is presented. The controller generates a path of shortest distance by determining lateral coordinates on a longitudinal grid, while respecting road bounds. This path is then parameterized by arc length before being optimized to restrict the normal acceleration values along the trajectory's arc length. The optimized tra-jectory is then tracked using a nonlinear model predictive control scheme using a bicycle plant model to calculate an optimal steering angle for the tires. The proposed controller is evaluated in simulation during a double-lane-change maneuver, where it generates and tracks a reference trajectory while observing the road boundaries and acceleration limits. Its performance is compared to a controller without path optimization, along with another that uses a smooth, predetermined, reference path instead of creating its own initial reference. It is shown that the proposed controller improves the tracking compared to a controller without path optimization, with a four-times reduction in average lateral tracking error. The average lateral acceleration is also reduced by 6%. The controller also maintains the tracking performance of a controller that uses a smooth reference path, while showing a much greater flexibility due to its ability to create its own initial reference path rather than having to follow a predetermined trajectory

Coexisting Chalcophile and Lithophile Uranium in Qingzhen (EH3) Chondrite

Mineralogical and textural studies of Qingzhen have shown that it is highly unequilibrated and that it contains a population of chondrules and isolated enstatite grains which preserve the record of more oxidizing nebular conditions (Rambaldi et al., 1983, 1984). Even though in the majority of cases these objects have been affected by various degrees of reduction, some still contain silicates with high (up to 10%) FeO contents