The Sun, stellar-population models, and the age estimation of high-redshift galaxies

Given sufficiently deep optical spectroscopy, the age estimation of high-redshif t ($z > 1$) galaxies has been claimed to be a relatively robust process (e.g. Dunlop et al. 1996) due to the fact that, for ages $< 5$Gyr, the near-ultraviolet light of a stellar population is expected to be dominated by `well-understood' main-sequence (MS) stars. Recently, however, the reliability of this process has been called into question by Yi et al (2000), who claim to have developed models in which the spectrum produced by the main sequence reddens much more rapidly than in the models of Jimenez et al (2000a), leading to much younger age estimates for the reddest known high-redshift ellipticals. In support of their revised age estimates, Yi et al cite the fact that their models can reproduce the spectrum of the Sun at an age of 5 Gyr, whereas the solar spectrum is not reproduced by the Jimenez et al models until $\simeq 10$ Gyr. Here we confirm this discrepancy, but point out that this is in fact a {\it strength} of the Jimenez et al models and indicative of some flaw in the models of Yi et al (which, in effect, imply that the Sun will turn into a red giant any minute now). We have also explored the models of Worthey (1994) (which are known to differ greatly from those of Jimenez et al in the treatment of post-MS evolution) and find that the main-sequence component of Worthey's models also cannot reproduce the solar spectrum until an age of 9-10 Gyr. We conclude that either the models of Yi et al are not as main-sequence dominated at 4-5 Gyr as claimed, or that the stellar evolutionary timescale in these models is in error by a factor possibly as high as two. (abridged)Comment: Submitted to MNRAS, final versio

Small task-oriented groups : a systems analysis : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Education at Massey University

Where two or more people are gathered together in order to engage in social interaction - there is a social system". (Anon.) The question of why it is that people come together in systems of interaction and how these systems persist as viable social arrangements is one which has been taken up by social philosophers and sociological theorists as far back as Hobbes. Subsequently Spencer, Durkheim, and such contemporary figures as Homans, Merton and Parsons have also taken issue with this problem. The present thesis shares a similar concern with the problem and derives its stimulus from the way in which sociologists have attempted to formulate adequate explanatory theories. The thesis exhibits a convergence in the interests of the two authors - on the one hand, an interest in the application of parsonian theory' to small group phenomena, and on the other, the use of 'systems theory' in the explanation of social interaction in educational settings. The specific focus of attention is on those groups which have the properties of being small and task-oriented. Such groups are ubiquitous in educational contexts. At the most general level the thesis uses Parsons' voluntaristic theory of social action as the frame of reference from which a theory of small task-oriented groups can be derived. The thesis is therefore an expedition into the realms of sociological theory and an exploration of the way in which parsons' theory in particular can be applied to an empirical situation. Elements of general systems theory have been employed to further limit the scope of the investigation by focussing only on the internal dynamic of small task-oriented groups, rather than the way in which they adapt to their surrounding environments, thus enabling such groups to be conceptualised as discrete social systems in their own right. [From Introduction

Subsidization of the Biofuel Industry: Security vs. Clean Air?

Replaced with revised version of paper 07/11/06.Resource /Energy Economics and Policy,

Sustainable sidedress nitrogen applications for early corn and cotton crops using small unmanned aerial systems

Nitrogen run-off from agriculture have been linked to human health problems on a global level. Large-scale conventional producers struggle to redefine themselves as sustainable because reducing nitrogen (N) inputs without justification or validation may lead to severe profit losses. Small unmanned aerial systems (sUAS) sensing may allow for decreased N runoff. Failure to address this problem will exacerbate already excessive N runoff into the Mississippi River and beyond. The purpose of this study was to reduce fertilizer N input using sUAS technology to assess crop canopy needs. In 2020 and 2021, variable rate nitrogen (VRN) side-dress N application maps were calculated on early corn and cotton crops sensed with MicaSense® technology. The SCCCI and FENDVI VIs most often were highly related by SEq to early corn and cotton canopy N status. VariRite™ technology was successfully implemented in producer’s fields using VI calibrated imagery captured from sUAS

The construction of a test of arithmetical concept thinking for grades seven and eight

Thesis (M.A.)--Boston University, 1948. This item was digitized by the Internet Archive

Understanding the aspirations of the elderly as a prelude to marketing public education.

This study explores ways for public schools to build political support among elderly citizens by responding to their concerns and needs. Basic marketing principles, used by industry to increase a corporation\u27s market share, are applied to fit the context of local school districts and the elderly. Literature reviews of marketing, the elderly, the needs of the elderly, and elderly issues in other institutions are included in this work. This study focused on people who are over the age of sixty-five living in Wareham Massachusetts. Once the demographics of this segment were identified, the needs, wants, and desires of the individuals in this segment were explored through the use of a survey and by conducting interviews. Included in the appendix is a marketing plan for the Wareham Public Schools, which is intended to address the needs, wants, and desires of the elderly in Wareham Massachusetts and to illustrate an approach that could be implemented elsewhere

Radial versus femoral access for rotational atherectomy: A UK observational study of 8622 patients

Background—Rotational atherectomy (RA) is an important interventional tool for heavily calcified coronary lesions. We compared the early clinical outcomes in patients undergoing RA using radial or femoral access. Methods and Results—We identified all patients in England and Wales who underwent RA between January 1, 2005, and March 31, 2014. Eight thousand six hundred twenty-two RA cases (3069 radial and 5553 femoral) were included in the analysis. The study primary outcome was 30-day mortality. Propensity scores were calculated to determine the factors associated with treatment assignment to radial or femoral access. Multivariable logistic regression analysis, using the calculated propensity scores, was performed. Thirty-day mortality was 2.2% in the radial and 2.3% in the femoral group (P=0.76). Radial access was associated with equivalent 30-day mortality (adjusted odds ratio [OR], 1.06; 95% confidence interval [CI], 0.77–1.46; P=0.71), procedural success (OR, 1.04; 95% CI, 0.84–1.29; P=0.73), major adverse cardiac and cerebrovascular events (OR, 1.05; 95% CI, 0.80–1.38; P=0.72), and net adverse clinical events (OR, 0.90; 95% CI, 0.71–1.15; P=0.41), but lower rates of in-hospital major bleeding (OR, 0.62; 95% CI, 0.40–0.98; P=0.04) and major access site complications (OR, 0.05; 95% CI, 0.01–0.38; P=0.004), compared with femoral access. Conclusions—In this large real-world study of patients undergoing RA, radial access was associated with equivalent 30-day mortality and procedural success, but reduced major bleeding and access site complications, compared with femoral access