On the deleted squares of lens spaces

The configuration space $F_2 (M)$ of ordered pairs of distinct points in a manifold $M$, also known as the deleted square of $M$, is not a homotopy invariant of $M$: Longoni and Salvatore produced examples of homotopy equivalent lens spaces $M$ and $N$ of dimension three for which $F_2 (M)$ and $F_2 (N)$ are not homotopy equivalent. In this paper, we study the natural question whether two arbitrary $3$-dimensional lens spaces $M$ and $N$ must be homeomorphic in order for $F_2 (M)$ and $F_2 (N)$ to be homotopy equivalent. Among our tools are the Cheeger--Simons differential characters of deleted squares and the Massey products of their universal covers.Comment: 27 pages, 10 figure

Trumpet Initial Data for Boosted Black Holes

We describe a procedure for constructing initial data for boosted black holes in the moving-punctures approach to numerical relativity that endows the initial time slice from the outset with trumpet geometry within the black hole interiors. We then demonstrate the procedure in numerical simulations using an evolution code from the Einstein Toolkit that employs 1+log slicing. The Lorentz boost of a single black hole can be precisely specified and multiple, widely separated black holes can be treated approximately by superposition of single hole data. There is room within the scheme for later improvement to re-solve (iterate) the constraint equations in the multiple black hole case. The approach is shown to yield an initial trumpet slice for one black hole that is close to, and rapidly settles to, a stationary trumpet geometry. Initial data in this new approach is shown to contain initial transient (or "junk") radiation that is suppressed by as much as two orders of magnitude relative to that in comparable Bowen-York initial data.Comment: 18 pages, 18 figure

A Comparison of Academic Achievement and Value-Added Grades on the State Report Cards in Tennessee, 2001-2003.

This study uses the state report cards published by the Tennessee Department of Education to compare the academic achievement grades to the value-added grades to determine if there is a relationship between the two grading systems. The data used for this study are from the 2001, 2002, and the 2003 state report cards published for each school using the five subject areas of reading, language, math, science, and social studies. One thousand sixty schools in the state of Tennessee were for this study. The socioeconomic status (SES) of the schools was used as a covariate to determine if the socioeconomic status of the school has an effect on the relationship between achievement grades and value-added grades on the state report card. Schools were grouped into one of three categories. Schools with 0 – 33% of their students eligible for free/reduced meals were categorized as an upper SES school. Schools with 34-66% of their students eligible for free/reduced meals were categorized as a middle SES school, and schools with 67-100% of their students eligible for free/reduced meals were categorized as a lower SES school. The data used to determine the grades on the report card are based upon the results of the state mandated achievement tests given in the state of Tennessee. The 3 cumulative three year averages of the normal curve equivalent scores (NCEs) are used to determine the achievement grades while the cumulative three-year value-added percentages are used to determine the value-added grades on the state report cards. There was a statistically significant relationship between academic achievement grades and value-added grades in math, language, and social studies on the 2001, 2002, and 2003 state report cards. In reading, the 2002 state report card did not show a significant relationship between the grades while the 2001 and 2003 report cards did indicate a significant relationship. In science, the 2001 and 2003 report cards did not indicate a significant relationship between achievement and value-added grades while the 2002 report card did indicate a significant relationship between the grades

Neuropsychological outcome and player characteristics in amateur soccer players

A growing body of research suggests that the game of soccer causes neurophysiological damage and neuropsychological deficits in its players. This research project evaluated player characteristics, including aggression, position, heading frequency, and head injuries in an attempt to delineate the effect of traumatic head injuries from the possible detrimental effects of heading the ball. Fifty-three male, amateur soccer players participated in a brief neuropsychological evaluation and a structured interview. Findings revealed that the number of years played (r=.30, p=.03) and an index score representing the number of competitive seasons (r=.44, p=001) were the only player characteristics that correlated with test performance. Results also suggest that past research has underestimated the connection between heading frequency and aggression (r\u3e.4, p [is less than or equal to] .002), a variable that may be related to head injury

GNSS Signal Authentication via Power and Distortion Monitoring

We propose a simple low-cost technique that enables civil Global Positioning System (GPS) receivers and other civil global navigation satellite system (GNSS) receivers to reliably detect carry-off spoofing and jamming. The technique, which we call the Power-Distortion detector, classifies received signals as interference-free, multipath-afflicted, spoofed, or jammed according to observations of received power and correlatio n function distortion. It does not depend on external hardware or a network connection and can be readily implemented on many receivers via a firmware update. Crucially, the detector can with high probability distinguish low-power spoofing from ordinary multipath. In testing against over 25 high-quality empirical data sets yielding over 900,000 separate detection tests, the detector correctly alarms on all malicious spoofing or jamming attack s while maintaining a <0.5% single-channel false alarm rate.Aerospace Engineering and Engineering Mechanic

Performance of Non-Contact Flow Meters in Irrigation Canals and Surface Drains

Flow measurement is an important component of modern irrigation delivery systems. As irrigation projects are modernized, flow measurement devices are being installed in more non-traditional applications. Some applications feature a combination of characteristics that eliminate traditional flow measurement structures. Furthermore, as regulations obligate more districts to report real time diversions, redundant flow measurement devices using different methods or technologies become necessary to reduce the potential for temporary gaps in diversion data. In these cases, non-contact type flow measurement devices may be of interest. Two non-contact flow meters were installed at different irrigation district canals. Data was collected from the non-contact meters as well as a pre-existing flow measurement device operating in parallel. In addition, intermittent current metering was conducted at each site and used as the standard for calibration purposes. This paper presents an analysis of the flow measurement data collected and a discussion of the non-contact meter performance in open channel irrigation system applications