Electrical power dissipation in carbon nanotubes on single crystal quartz and amorphous SiO2

Heat dissipation in electrically biased semiconducting carbon nanotubes (CNTs) on single crystal quartz and amorphous SiO2 is examined with temperature profiles obtained by spatially resolved Raman spectroscopy. Despite the differences in phonon velocities, thermal conductivity and van der Waals interactions with CNTs, on average, heat dissipation into single crystal quartz and amorphous SiO2 is found to be similar. Large temperature gradients and local hot spots often observed underscore the complexity of CNT temperature profiles and may be accountable for the similarities observed

Buckets of Water into the Ocean: Non-public Revenue in Public Charter and Traditional Public Schools

The funding of K-12 education remains a contentious public policy issue. Questions of funding adequacy and equity across school sectors, school districts and individual schools are prominent in discussions of how to improve educational outcomes, especially for students from disadvantaged backgrounds (Downes & Stiefel 2008; Ladd 2008). Although scholars are divided regarding the extent to which money affects student outcomes in K-12 education (Jackson, Johnson, & Persico 2015; Hanushek, 1997; Burtless 1996), there is basic agreement that more education revenue is better so long as the increased resources are directed towards productive educational activities and programs (Murnane & Levy 1996). If you ask education practitioners, the majority will say that more resources will make their schools better

A new method to study energy-dependent arrival delays on photons from astrophysical sources

Correlations between the arrival time and the energy of photons emitted in outbursts of astrophysical objects are predicted in quantum and classical gravity scenarios and can appear as well as a result of complex acceleration mechanisms responsible for the photon emission at the source. This paper presents a robust method to study such correlations that overcomes some limitations encountered in previous analysis, and is based on a Likelihood function built from the physical picture assumed for the emission, propagation and detection of the photons. The results of the application of this method to a flare of Markarian 501 observed by the MAGIC telescope are presented. The method is also applied to a simulated dataset based on the flare of PKS 2155-304 recorded by the H.E.S.S. observatory to proof its applicability to complex photon arrival time distributions.Comment: 18 pages, 7 figure

Charter School Funding: Inequity Expands

The revenue study is based on Fiscal Year 2010‒11 (FY11) data for each of 30 selected states plus the District of Columbia (D.C.). Traditional school districts and public charter schools were analyzed and aggregated “statewide.” For each state, one to three “focus areas” were selected based on larger concentrations of charter students – most focus areas are large cities, some are metropolitan counties. Traditional school districts and charter schools were analyzed separately in each focus area. The analytic team collected and analyzed all revenues, public and private, flowing to traditional district and public charter schools. FY11 funding includes Federal, State, Local, Other, PublicIndeterminate, and Indeterminate sources

The Productivity of Public Charter Schools

This is the first national study of the productivity of public charter schools relative to district schools. This report is a follow up to the charter school revenue study, Charter School Funding: Inequity Expands, released in April 2014 by the School Choice Demonstration Project at the University of Arkansas. That study was authored by the same research team that crafted this report. In the revenue study, per pupil revenues for public charter schools and traditional public schools (TPS) were compared. The research team found that during the 2010-11 school year (FY11), charter-school students across 30 states and the District of Columbia on average received $3,814 less in funding than TPS students, a funding gap of 28.4 percent

Topology of the conceptual network of language

We define two words in a language to be connected if they express similar concepts. The network of connections among the many thousands of words that make up a language is important not only for the study of the structure and evolution of languages, but also for cognitive science. We study this issue quantitatively, by mapping out the conceptual network of the English language, with the connections being defined by the entries in a Thesaurus dictionary. We find that this network presents a small-world structure, with an amazingly small average shortest path, and appears to exhibit an asymptotic scale-free feature with algebraic connectivity distribution.Comment: 4 pages, 2 figures, Revte