Spheromak Experiment Using Separate Guns For Formation And Sustainment

An experiment is described that incorporates the use of separate magnetized plasma guns for formation and sustainment of a spheromak. It is shown that energy coupling efficiency approaches unity if the gun and spheromak are of comparable size. A large gun should be able to operate at lower current and therefore lower voltage. In addition, it is expected that a gun matched to the size of the spheromak will cause less perturbation to the equilibrium. It is proposed to use a smaller gun for spheromak formation and a large, efficient gun for sustainment. The theoretical basis for the experiment is developed, and the details of the experiment are described. A prediction of the equilibrium magnetic flux surfaces using the EFIT code is presented

PRICE VERSUS QUOTA REDUCTIONS: U.S. FLUE-CURED TOBACCO POLICY

Declining domestic cigarette consumption, increased global competition, and loss of import restrictions indicate decreased demand for U.S. flue-cured tobacco. The effects of 10% declines in domestic and export demand are evaluated under a policy of reducing quota to maintain price versus a policy of allowing price to fall to maintain quota. Changes in prices, quantities, revenues, and economic rents are simulated. Losses to nonfarming quota owners are minimized under a policy of price maintenance, while losses in revenues to tobacco-producing areas are minimized by a policy of quota maintenance. Aggregate losses to tobacco growers are greater under a policy of quota maintenance.Flue-cured, Policy, Price reduction, Quota, Tobacco, Agricultural and Food Policy,

The role and effects of teaching assistants in English primary schools (Years 4 to 6) 2000-2003. Results from the Class Size and Pupil-Adult Ratios (CSPAR) KS2 Project

It is widely assumed that increasing the number of Teaching Assistants (TAs) in the classroom will be beneficial to children, and this is one important aim of the recently implemented Workforce Agreement. But there are still significant gaps in knowledge about many aspects of their deployment and impact. The Class Size and Pupil-Adult Ratio (CSPAR) KS2 study built on earlier findings when the pupils were in reception and KS1 and investigated: 1. the deployment of TAs in classrooms and how key parties involved perceived this; 2. the effect of TAs on interactions involving pupils and teachers in the same classrooms, and on pupil attainments. The study had a longitudinal, mixed method and multi-informant design. There were 202 schools, 332 classes and 8728 pupils in Y4. Methods of data collection included: for the whole sample) questionnaires completed by TAs, teachers and head teachers, assessments of pupil attainments in mathematics, English and science, data on pupil background, and (for a sub-sample) case studies and a systematic observation study. This study found that the TA’s role in KS2 is predominantly a direct one, in the sense of face-to-face interactions supporting certain pupils. There was no evidence that the presence of TAs, or any characteristic of TAs, had a measurable effect on pupil attainment. However, results were clear in showing that TAs had an indirect effect on teaching, e.g., pupils had a more active form of interaction with the teacher and there was more individualised teacher attention. This supported teachers’ views that TAs are effective in supporting them in this way. We conclude that more attention needs to be paid to what we call the pedagogical role of TAs so that they can be used effectively to help teachers and pupils, particularly in the context of the enhanced roles for TAs being introduced as part of the Government’s remodeling agenda

Texas Natural Resources Inventory and Monitoring System (TNRIMS), Applications System Verification and Transfer (ASVT), Remote Sensing Information Subsystem (RSIS): Acceptance test procedures

There are no author-identified significant results in this report

Stars that Move Together Were Born Together

It is challenging to reliably identify stars that were born together outside of actively star-forming regions and bound stellar systems. However, co-natal stars should be present throughout the Galaxy, and their demographics can shed light on the clustered nature of star formation and the dynamical state of the disk. In previous work we presented a set of simulations of the Galactic disk that followed the clustered formation and dynamical evolution of 4 billion individual stars over the last 5 Gyr. The simulations predict that a high fraction of co-moving stars with physical and 3D velocity separation of $\Delta r < 20$ pc and $\Delta v < 1.5$ km s$^{-1}$ are co-natal. In this \textit{Letter}, we use \textit{Gaia} DR2 and LAMOST DR4 data to identify and study co-moving pairs. We find that the distribution of relative velocities and separations of pairs in the data is in good agreement with the predictions from the simulation. We identify 111 co-moving pairs in the Solar neighborhood with reliable astrometric and spectroscopic measurements. These pairs show a strong preference for having similar metallicities when compared to random field pairs. We therefore conclude that these pairs were very likely born together. The simulations predict that co-natal pairs originate preferentially from high-mass and relatively young ($< 1$ Gyr) star clusters. \textit{Gaia} will eventually deliver well-determined metallicities for the brightest stars, enabling the identification of thousands of co-natal pairs due to disrupting star clusters in the solar neighborhood.Comment: 6 pages, 4 figures, 1 table. Submitted to ApJL. Catalog here: http://harshilkamdar.github.io/2019/04/03/pairs.htm

The Impact of Rotation on the Evolution of Low-Mass Stars

High precision photometry and spectroscopy of low-mass stars reveal a variety of properties standard stellar evolution cannot predict. Rotation, an essential ingredient of stellar evolution, is a step towards resolving the discrepancy between model predictions and observations. The first rotating stellar model, continuously tracing a low-mass star from the pre-main sequence onto the horizontal branch, is presented. The predicted luminosity functions of globular clusters and surface rotation velocities on the horizontal branch are discussed.Comment: 5 pages, 6 figures, to be published in the Proceedings of the Conference 'Unsolved Problems in Stellar Physics', Cambridge, 2-6 July 200

3D Monte Carlo radiation transfer modelling of photodynamic therapy

We acknowledge the support of the UK Engineering and Physics Sciences Research Council (EPSRC) for funding through a studentship for C L Campbell as well as the Alfred Stewart Trust.The effects of ageing and skin type on Photodynamic Therapy (PDT) for different treatment methods have been theoretically investigated. A multilayered Monte Carlo Radiation Transfer model is presented where both daylight activated PDT and conventional PDT are compared. It was found that light penetrates deeper through older skin with a lighter complexion, which translates into a deeper effective treatment depth. The effect of ageing was found to be larger for darker skin types. The investigation further strengthens the usage of daylight as a potential light source for PDT where effective treatment depths of about 2 mm can be achieved.Publisher PD

Antikaon Production in Proton-Nucleus Reactions and the K−K^- properties in nuclear matter

We calculate the momentum-dependent potentials for $K^+$ and $K^-$ mesons in a dispersion approach at nuclear density $\rho_0$ using the information from the vacuum $K^+ N$ and $K^- N$ scattering amplitudes, however, leaving out the resonance contributions for the in-medium analysis. Whereas the $K^+$ potential is found to be repulsive ($\approx$ + 30 MeV) and to show only a moderate momentum dependence, the $K^-$ selfenergy at normal nuclear matter density turns out to be $\approx$ - 200 MeV at zero momentum in line with kaon atomic data, however, decreases rapidly in magnitude for higher momenta. The antikaon production in p + A reactions is calculated within a coupled transport approach and compared to the data at KEK including different assumptions for the antikaon potentials. Furthermore, detailed predictions are made for $p + ^{12}C$ and $p + ^{207}Pb$ reactions at 2.5 GeV in order to determine the momentum dependent antikaon potential experimentally.Comment: 27 pages, LaTeX, including 14 ps-figures, UGI-98-1

The Weak Clustering of Gas-Rich Galaxies

We examine the clustering properties of HI-selected galaxies through an analysis of the HI Parkes All-Sky Survey Catalogue (HICAT) two-point correlation function. Various sub-samples are extracted from this catalogue to study the overall clustering of HI-rich galaxies and its dependence on luminosity, HI gas mass and rotational velocity. These samples cover the entire southern sky Dec < 0 deg, containing up to 4,174 galaxies over the radial velocity range 300-12,700 km/s. A scale length of r_0 = 3.45 +/- 0.25 Mpc/h and slope of gamma = 1.47 +/- 0.08 is obtained for the HI-rich galaxy real-space correlation function, making gas-rich galaxies among the most weakly clustered objects known. HI-selected galaxies also exhibit weaker clustering than optically selected galaxies of comparable luminosities. Good agreement is found between our results and those of synthetic HI-rich galaxy catalogues generated from the Millennium Run CDM simulation. Bisecting HICAT using different parameter cuts, clustering is found to depend most strongly on rotational velocity and luminosity, while the dependency on HI mass is marginal. Splitting the sample around v_rot = 108 km/s, a scale length of r_0 = 2.86 +/- 0.46 Mpc/h is found for galaxies with low rotational velocities compared to r_0 = 3.96 +/- 0.33 Mpc/h for the high rotational velocity sample.Comment: Accepted for publication in the Astrophysical Journa