The American Community Survey

Analytical data report #15 is the latest in a series of bulletins designed to complement our traditional data releases. The American Community Survey (ACS) is a continuous household survey conducted by the United States Census Bureau that will replace the long-form of the traditional decennial Census. ADR #15 provides background information on the ACS and the benefits and challenges associated with its use. The report also reviews some of the estimates currently available for the region's nine counties and six largest municipalities and, based on this data, discusses demographic changes in the Delaware Valley between 2000 and 2006

Sudden Critical Current Drops Induced in S/F Structures

In the search for new physical properties of S/F structures, we have found that the superconductor critical current can be controlled by the domain state of the neighboring ferromagnet. The superconductor is a thin wire of thickness d_{s} ~ 2 xi_{S}. Nb/Co and Nb/Py (Permalloy Ni_{80}Fe_{20}) bilayer structures were grown with a significant magnetic anisotropy. Critical current measurements of Nb/Co structures with ferromagnet thickness d_{F} > 30nm show sudden drops in two very defined steps when the measurements are made along the hard axes direction (i.e. current track parallel to hard anisotropy axes direction). These drops disappear when they are made along the easy axis direction or when the ferromagnet thickness is below 30nm. The drops are accompanied by vortex flux flow. In addition magnetorestistance measurements close to Tc show a sharp increase near saturation fields of the ferromagnet. Similar results are reproduced in Nb/Py bilayer structure with the ferromagnet thickness d_{F} ~ 50nm along the easy anisotropy axes. These results are explained as being due to spontaneous vortex formation and flow induced by Bloch domain walls of the ferromagnet underneath. We argue these Bloch domain walls produce a 2D vortex-antivortex lattice structure.Comment: 6 pages, 6 figure

Computer performance analysis - Measurement objectives and tools

Objectives and measurements in computer performance analysi

Amplitude control of quantum interference

Usually, the oscillations of interference effects are controlled by relative phases. We show that varying the amplitudes of quantum waves, for instance by changing the reflectivity of beam splitters, can also lead to quantum oscillations and even to Bell violations of local realism. We first study theoretically a generalization of the Hong-Ou-Mandel experiment to arbitrary source numbers and beam splitter transmittivity. We then consider a Bell type experiment with two independent sources, and find strong violations of local realism for arbitrarily large source number $N$; for small $N$, one operator measures essentially the relative phase of the sources and the other their intensities. Since, experimentally, one can measure the parity of the number of atoms in an optical lattice more easily than the number itself, we assume that the detectors measure parity.Comment: 4 pages; 4 figure

E-Learning Works - Exactly How Well Depends on its Unique Features and Barriers

Key Findings: E-learning is comparable to traditional teacher-led classroom instruction in terms of effectiveness. E-learning has specific features that may influence learning: content, immersion, interactivity, and communication. Barriers to e-learning adoption include fraud and cheating, digital divides and their impact on low income and underprepared students, and cost issues

E-Learning in Postsecondary Education

Over the past decade postsecondary education has been moving increasingly from the class room to online. During the fall 2010 term 31 percent of U.S. college students took at least one online course. The primary reasons for the growth of e-learning in the nation\u27s colleges and universities include the desire of those institutions to generate new revenue streams, improve access, and offer students greater scheduling flexibility. Yet the growth of e-learning has been accompanied by a continuing debate about its effectiveness and by the recognition that a number of barriers impede its widespread adoption in higher education

Bounds for Non-Locality Distillation Protocols

Non-locality can be quantified by the violation of a Bell inequality. Since this violation may be amplified by local operations an alternative measure has been proposed - distillable non-locality. The alternative measure is difficult to calculate exactly due to the double exponential growth of the parameter space. In this article we give a way to bound the distillable non-locality of a resource by the solutions to a related optimization problem. Our upper bounds are exponentially easier to compute than the exact value and are shown to be meaningful in general and tight in some cases.Comment: 8 pages, 3 figures; small changes in introduction and application section due to the exact verification of distillation bounds using a symbolic computation package (Maple 14); added journal re

Estimating Water Demand Schedules for Selected Industries in Arkansas

Water demand functions for the paper and chemical industries in the state of Arkansas were estimated utilizing data collected from individual plants throughout the state. Regression analysis was used to estimate demand functions from a data base which included information on intake and gross water use by source, recirculated water use, costs of acquiring, treating, and discharging water, plant output, employment, and level of technology. The demand for intake water was estimated as an exponential function of average water costs and the level of technology primarily. Price elasticities of demand were estimated as approximately equal to one for both industries. The results of this study could be used to determine the effects of various public policies on the withdrawal of water for industrial purposes

Generalized Derivations with Commutativity and Anti-commutativity Conditions

Let R be a prime ring with 1, with char(R) &#8800; 2; and let F : R &#8594; R be a generalized derivation. We determine when one of the following holds for all x,y &#8712; R: (i) [F(x); F(y)] = 0; (ii) F(x)&#927;F(y) = 0; (iii) F(x) &#927; F(y) = x &#927; y .</p