Locally linear embedding: dimension reduction of massive protostellar spectra

We present the results of the application of locally linear embedding (LLE) to reduce the dimensionality of dereddened and continuum subtracted near-infrared spectra using a combination of models and real spectra of massive protostars selected from the Red MSX Source survey database. A brief comparison is also made with two other dimension reduction techniques; Principal Component Analysis (PCA) and Isomap using the same set of spectra as well as a more advanced form of LLE, Hessian locally linear embedding. We find that whilst LLE certainly has its limitations, it significantly outperforms both PCA and Isomap in classification of spectra based on the presence/absence of emission lines and provides a valuable tool for classification and analysis of large spectral data sets.Comment: 8 pages, 7 figures. Accepted for publication in MNRAS 2016 June 2

Digital automatic gain amplifier

A circuit is described for adjusting the amplitude of a reference signal to a predetermined level so as to permit subsequent data signals to be interpreted correctly. The circuit includes an operational amplifier having a feedback circuit connected between an output terminal and an input terminal; a bank of relays operably connected to a plurality of resistors; and a comparator comparing an output voltage of the amplifier with a reference voltage and generating a compared signal responsive thereto. Means is provided for selectively energizing the relays according to the compared signal from the comparator until the output signal from the amplifier equals to the reference signal. A second comparator is provided for comparing the output of the amplifier with a second voltage source so as to illuminate a lamp when the output signal from the amplifier exceeds the second voltage

On the Running of the Cosmological Constant in Quantum General Relativity

We present arguments that show what the running of the cosmological constant means when quantum general relativity is formulated following the prescription developed by Feynman.Comment: 5 page

From 2D Integrable Systems to Self-Dual Gravity

We explain how to construct solutions to the self-dual Einstein vacuum equations from solutions of various two-dimensional integrable systems by exploiting the fact that the Lax formulations of both systems can be embedded in that of the self-dual Yang--Mills equations. We illustrate this by constructing explicit self-dual vacuum metrics on $\R^2\times \Sigma$, where $\Sigma$ is a homogeneous space for a real subgroup of SL(2, \C) associated with the two-dimensional system.Comment: 9 pages, LaTex, no figure

Taking A Stand: The Effects Of Standing Desks On Task Performance And Engagement

Time spent sitting is associated with negative health outcomes, motivating some individuals to adopt standing desk workstations. This study represents the first investigation of the effects of standing desk use on reading comprehension and creativity. In a counterbalanced, within-subjects design, 96 participants completed reading comprehension and creativity tasks while both sitting and standing. Participants self-reported their mood during the tasks and also responded to measures of expended effort and task difficulty. In addition, participants indicated whether they expected that they would perform better on work-relevant tasks while sitting or standing. Despite participants’ beliefs that they would perform worse on most tasks while standing, body position did not affect reading comprehension or creativity performance, nor did it affect perceptions of effort or difficulty. Mood was also unaffected by position, with a few exceptions: Participants exhibited greater task engagement (i.e., interest, enthusiasm, and alertness) and less comfort while standing rather than sitting. In sum, performance and psychological experience as related to task completion were nearly entirely uninfluenced by acute (~30-min) standing desk use. View Full-Tex

ROSAT observations of the dwarf starforming galaxy Holmerg II (UGC 4305)

We present ROSAT PSPC and HRI observations of the dwarf irregular galaxy Holmberg II (UGC4305). This is one of the most luminous dwarf galaxies (Lx~ 10^{40} erg s^{-1} cm^{-2}) detected in the ROSAT All-Sky Survey. The X-ray emission comes from a single unresolved point source, coincident with a large HII region which emits intense radio emission. The source is variable on both year and day timescales, clearly favouring accretion into a compact object rather than a supernova remnant or a superbubble interpretation for the origin of the X-ray emission. However, its X-ray spectrum is well-fit by a a Raymond-Smith spectrum with kT~0.8 keV, lower than the temperature of X-ray binaries in nearby spiral galaxies.Comment: Accepted for publication in MNRA

Chlamydia diagnosis rate in England in 2012: an ecological study of local authorities

Objectives Local authorities (LAs) in England commission chlamydia screening as part of the National Chlamydia Screening Programme. It is recommended that LAs achieve a chlamydia diagnosis rate of ≥2300 cases per 100 000 population aged 15–24. We describe national patterns in attainment of the chlamydia diagnosis rate recommendation and possible implications of using it to measure LA-level performance. Methods We used publicly available data sets from England (2012) to explore the association between LAs attaining the recommended chlamydia diagnosis rate and population size, socioeconomic deprivation, test setting and sex. Results We used data from 1 197 121 recorded chlamydia tests in females and 564 117 in males. The chlamydia diagnosis rate recommendation was achieved by 22% (72/324) of LAs overall (43% female population; 8% male population). LAs in the highest deprivation quintile were more likely to reach the recommendation than those in the least-deprived quintile for both sexes (women: unadjusted prevalence ratio (UPR) 7.43, 95% CI 3.65 to 15.11; men: UPR 7.00, 95% CI 1.66 to 29.58). The proportion of tests performed in genitourinary medicine clinics was negatively associated with attainment of the recommended diagnosis rate (UPR 0.95, 0.93 to 0.97). Conclusions Chlamydia diagnosis rate recommendations that reflect local area deprivation (as a proxy for disease burden) may be more appropriate than a single national target if the aim is to reduce health inequalities nationally. We suggest LAs monitor their chlamydia diagnosis rate, test coverage and test positivity across a range of measures (including setting and sex) and pre/post changes to commissioned services. Critical evaluation of performance against the recommendation should be reflected in local commissioning decisions

Estimates of Radiation by Superluminal Neutrinos

We show that the more energetic superluminal neutrinos with quadratically dispersed superluminalities \delta=\beta^2-1, for \beta=v/c where v is the neutrino velocity, also lose significant energy to radiation to the \nu+e^-+e^+ final state in travelling from CERN to Gran Sasso as has been shown to occur for those with constant superluminality by Cohen and Glashow if indeed \delta \simeq 5\times 10^{-5}. In addition, we clarify the dependence of such radiative processes on the size of the superluminality.Comment: 6 pages, no figures; text re-arranged for journal purposes; improved references; published version(title changed by Editors

An airborne remote sensing system for urban air quality

Several NASA sponsored remote sensors and possible airborne platforms were evaluated. Outputs of dispersion models for SO2 and CO pollution in the Washington, D.C. area were used with ground station data to establish the expected performance and limitations of the remote sensors. Aircraft/sensor support requirements are discussed. A method of optimum flight plan determination was made. Cost trade offs were performed. Conclusions about the implementation of various instrument packages as parts of a comprehensive air quality monitoring system in Washington are presented