Quality Counts 2011

On January 11, Education Week released its 15 th annual Quality Counts report. Since 1997, Education Week has been releasing yearly report cards for each state and the nation as a whole. These report cards attempt to measure educational progress and success in several areas as well as assign an overall letter grade to each state. Some of the grades assigned in the report cards measure the strength of states’ policies, while others measure educational inputs (school funding, job markets) or outputs (K-12 achievement

What counts as numeracy?

The purpose of the study was to infer the Scottish HMI view of what is meant by Numeracy given the concerns that primary children's achievements in Numeracy reflect a lack of flexibility in handling number and an overemphasis on procedures at the expense of understanding (HMI, 1997). Three hundred HMI reports on primary schools in Scotland were randomly selected. Content analysis of the sections on Number, Money and Measurement revealed Numeracy to be conceived of as computational proficiency and as understanding of number. Surprisingly, there were significantly more (p<0.05) references to computational proficiency than there were to understanding of number. The results are discussed in terms of what it means to understand number. It is suggested that there needs to be much clearer delineation of what is required and meant by the idea of understanding number

Cash counts

Does cash still count? Electronic payments in their many forms are a ubiquitous part of our culture and the U.S. economy. Many of us have our paychecks automatically deposited in our bank accounts. We use online bill payment services and frequently shop at our favorite virtual storefronts. Businesses increasingly use electronic payment methods—taking advantage of cost and efficiency gains to contribute to their bottom lines. With this commonplace use of electronic money, you might assume that paper payments are shrinking, and perhaps the predictions of a cashless society, which have persisted since the 1960s, will come true. While it is clear check usage is declining, at this point, it certainly isn’t clear for the other form of paper payments—cash.Paper money ; Money ; Dollar, American ; Electronic funds transfers ; Payment systems

Observation of Aubry transition in finite atom chains via friction

The highly nonlinear many-body physics of a chain of mutually interacting atoms in contact with a periodic substrate gives rise to complex static and dynamical phenomena, such as structural phase transitions and friction. In the limit of an infinite chain incommensurate with the substrate, Aubry predicted a structural transition with increasing substrate potential, from the chain's intrinsic arrangement free to slide on the substrate, to a pinned arrangement favoring the substrate pattern. To date, the Aubry transition has not been observed. Here, using a chain of cold ions subject to a periodic optical potential we qualitatively and quantitatively establish a close relation between Aubry's sliding-to-pinned transition and superlubricity breaking in stick-slip friction. Using friction measurements with high spatial resolution and individual ion detection, we experimentally observe the Aubry transition and the onset of its hallmark fractal atomic arrangement. Notably, the observed critical lattice depth for a finite chain agrees well with the Aubry prediction for an infinite chain. Our results elucidate the connection between competing ordering patterns and superlubricity in nanocontacts - the elementary building blocks of friction.Comment: 5 pages, 4 figure

Quantiles for Counts

This paper studies the estimation of conditional quantiles of counts. Given the discreteness of the data, some smoothness has to be artificially imposed on the problem. The methods currently available to estimate quantiles of count data either assume that the counts result from the discretization of a continuous process, or are based on a smoothed objective function. However, these methods have several drawbacks. We show that it is possible to smooth the data in a way that allows inference to be performed using standard quantile regression techniques. The performance and implementation of the estimator are illustrated by simulations and an application.Asymmetric maximum likelihood, Jittering, Maximum score estimator, Quantile regression, Smoothing.

VLA 1.4 GHz Catalogs of the Abell 370 and Abell 2390 Cluster Fields

We present 1.4 GHz catalogs for the cluster fields Abell 370 and Abell 2390 observed with the Very Large Array. These are two of the deepest radio images of cluster fields ever taken. The Abell 370 image covers an area of 40'x40' with a synthesized beam of ~1.7" and a noise level of ~5.7 uJy near field center. The Abell 2390 image covers an area of 34'x34' with a synthesized beam of ~1.4" and a noise level of ~5.6 uJy near field center. We catalog 200 redshifts for the Abell 370 field. We construct differential number counts for the central regions (radius < 16') of both clusters. We find that the faint (S_1.4GHz < 3 mJy) counts of Abell 370 are roughly consistent with the highest blank field number counts, while the faint number counts of Abell 2390 are roughly consistent with the lowest blank field number counts. Our analyses indicate that the number counts are primarily from field radio galaxies. We suggest that the disagreement of our counts can be largely attributed to cosmic variance.Comment: 13 pages, accepted for publication in ApJ