Heat and extension at mid- and lower crustal levels of the Rio Grande rift

The process by which large amounts (50 to 200 percent) of crustal extension are produced was concisely described by W. Hamilton in 1982 and 1983. More recently, England, Sawyer, P. Morgan and others have moved toward quantifying models of lithospheric thinning by incorporating laboratory and theoretical data on rock rheology as a function of composition, temperature, and strain rate. Hamilton's description identifies three main crustal layers, each with a distinctive mechanical behavior; brittle fracturing and rotation in the upper crust, discontinuous ductile flow in the middle crust and laminar ductile flow in the lower crust. The temperature and composition dependent brittle-ductile transition essentially defines the diffuse boundary between upper and middle crust. It was concluded that the heat responsible for the highly ductile nature of the lower crust and the lensoidal and magma body structures at mid-crustal depths in the rift was infused into the crust by relatively modest ( 10 percent by mass) magmatic upwelling (feeder dikes) from Moho levels. Seismic velocity-versus-depth data, supported by gravity modeling and the fact that volumes of rift related volcanics are relatively modest ( 6000 cubic km) for the Rio Grande system, all imply velocities and densities too small to be consistent with a massive, composite, mafic intrusion in the lower crust

Fourier phase and pitch-class sum

Music theorists have proposed two very different geometric models of musical objects, one based on voice leading and the other based on the Fourier transform. On the surface these models are completely different, but they converge in special cases, including many geometries that are of particular analytical interest.Accepted manuscrip

An Alternative Interpretation of Statistical Mechanics

In this paper I propose an interpretation of classical statistical mechanics that centers on taking seriously the idea that probability measures represent complete states of statistical mechanical systems. I show how this leads naturally to the idea that the stochasticity of statistical mechanics is associated directly with the observables of the theory rather than with the microstates (as traditional accounts would have it). The usual assumption that microstates are representationally significant in the theory is therefore dispensable, a consequence which suggests interesting possibilities for developing non-equilibrium statistical mechanics and investigating inter-theoretic answers to the foundational questions of statistical mechanics

Student Choice in Higher Education—Reducing or Reproducing Social Inequalities?

A hallmark of recent higher education policy in developed economies is the move towards quasi-markets involving greater student choice and provider competition, underpinned by cost-sharing policies. This paper examines the idealizations and illusions of student choice and marketization in higher education policy in England, although the overall conclusions have relevance for other countries whose higher education systems are shaped by neoliberal thinking. First, it charts the evolution of the student-choice rationale through an analysis of government commissioned reports, white papers, and legislation, focusing on policy rhetoric and the purported benefits of increasing student choice and provider competition. Second, the paper tests the predictions advanced by the student-choice rationale—increased and wider access, improved institutional quality, and greater provider responsiveness to the labour market—and finds them largely not met. Finally, the paper explores how conceptual deficiencies in the student-choice model explain why the idealization of student choice has largely proved illusionary. Government officials have narrowly conceptualized students as rational calculators primarily weighing the economic costs and benefits of higher education and the relative quality of institutions and programs. There is little awareness that student choices are shaped by several other factors as well and that these vary considerably by social background. The paper concludes that students’ choices are socially constrained and stratified, reproducing and legitimating social inequality

English and American higher education access and completion policy regimes: similarities, differences and possible lessons

Abstract or Description: England and the United States provide a very interesting pairing as countries with many similarities, but also instructive dissimilarities, with respect to their policies for higher education access and success. The purpose of this paper is to explore these similarities and dissimilarities with an eye to what each country can learn from the other with regard to reducing social class and racial/ethnic differences in higher education access and success. We focus on seven policy strands affecting higher education access and completion: student information provision; outreach from higher education institutions; student financial aid; affirmative action or contextualisation in higher education admissions; higher education efforts to improve retention and completion; performance funding; and degree of reliance on sub-baccalaureate institutions. While not exhaustive, this list of interventions is meant to focus on key policies affecting the undergraduate student experience and to give a sense of their range. We explore possible lessons that England and the United States might draw from each other’s experiences, mindful of the dangers of uncritical “policy tourism”. In the case of the United States, we note why and how it might benefit from following England in the use of Access Agreements to govern the outreach efforts of its universities, making more use of income-contingent loans, and expanding the range of information provided to prospective college students about the programmes and institutions they are considering. Meanwhile, in the case of England, we examine how it might benefit from greater focus on the role of further education colleges, sceptical consideration of proposals to make greater use of for-profit higher education, greater use of grant aid in its financial aid system, more policy attention to decisions students are making in primary and early secondary school that affect their preparation for higher education, greater use of contextualised admissions, and very careful consideration of the possible downsides of performance funding

Alumoxane/ferroxane nanoparticles for the removal of viral pathogens: the importance of surface functionality to nanoparticle activity

A bi-functional nano-composite coating has been created on a porous Nomex fabric support as a trap for aspirated virus contaminated water. Nomex fabric was successively dip-coated in solutions containing cysteic acid functionalized alumina (alumoxane) nanoparticles and cysteic acid functionalized iron oxide (ferroxane) nanoparticles to form a nanoparticle coated Nomex (NPN) fabric. From SEM and EDX the nanoparticle coating of the Nomex fibers is uniform, continuous, and conformal. The NPN was used as a filter for aspirated bacteriophage MS2 viruses using end-on filtration. All measurements were repeated to give statistical reliability. The NPN fabrics show a large decrease as compared to Nomex alone or alumoxane coated Nomex . An increase in the ferroxane content results in an equivalent increase in virus retention. This suggests that it is the ferroxane that has an active role in deactivating and/or binding the virus. Heating the NPN to 160 C results in the loss of cysteic acid functional groups (without loss of the iron nanoparticleﾒs core structure) and the resulting fabric behaves similar to that of untreated Nomex , showing that the surface functionalization of the nanoparticles is vital for the surface collapse of aspirated water droplets and the absorption and immobilization of the MS2 viruses. Thus, for virus immobilization, it is not sufficient to have iron oxide nanoparticles per se, but the surface functionality of a nanoparticle is vitally important in ensuring efficacy

Raman microscopy of lithium-manganese-rich transition metal oxide cathodes

Lithium-rich and manganese-rich (LMR) layered transition metal (TM) oxide composites with general formula xLi2MnO3 • (1- x)LiMO2 (M = Ni, Co, Mn) are promising cathode candidates for high energy density lithium ion batteries. Lithium-manganese-rich TM oxides crystallize as a nanocomposite layered phase whose structure further evolves with electrochemical cycling. Raman spectroscopy is a powerful tool to monitor the crystal chemistry and correlate phase changes with electrochemical behavior. While several groups have reported Raman spectra of lithium rich TM oxides, the data show considerable variability in terms of both the vibrational features observed and their interpretation. In this study, Raman microscopy is used to investigate lithium-rich and manganese-rich TM cathodes as a function of voltage and electrochemical cycling at various temperatures. No growth of a spinel phase is observed within the cycling conditions. However, analysis of the Raman spectra does indicate the structure of LMR-NMC deviates significantly from an ideal layered phase. The results also highlight the importance of using low laser power and large sample sizes to obtain consistent data sets