2,759 research outputs found

    Perspectives on Improving Teaching in Canadian Universities

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    As a result of increasing concerns about the quality of higher education in Canada, many universities have implemented programs and policies aimed at improving teaching. This study examines the perceptions of those individuals who are primarily responsible for teaching improvement activities at fifty-one Canadian degree-granting institutions. Respondents indicated the potential of each of thirty-six practices to improve teaching at their respective institutions. The findings reveal a widespread belief that the greatest teaching improvement potential lies in the provision of incentives to faculty in the form of employment rewards (appointment, tenure, promotion). The role of department heads, deans, and senior administrators in creating an institutional culture which encourages effective instruction is also seen as an important component of a teaching-improvement strategy. Other areas considered include activities and support structures which provide opportunities for faculty to develop their teaching abilities. Practices which seek to evaluate instruction for the purposes of making personnel decisions were seen as having the least potential to improve teaching.Afin de rĂ©pondre aux lacunes perçues quant Ă  la qualitĂ© de l'Ă©ducation post-secondaire au Canada, un nombre grandissant d'universitĂ©s sont implantĂ© des programmes et des politiques visant Ă  l'amĂ©lioration de l'enseignement. La prĂ©sente Ă©tude relève la perception des responsables de la pĂ©dagogie universitaire dans cinquante-et-une institutions qui dĂ©cernent des diplĂ´mes universitaires. Les rĂ©pondants ont estimĂ© le potentiel de chacune des trente-six pratiques ayant pour but d'amĂ©liorer la pĂ©dagogie dans leurs institutions respectives. Les rĂ©sultats rĂ©vèlent la croyance rĂ©pandue que le potentiel le plus important concernant l'amĂ©lioration  de l'enseignement  rĂ©side dans la stimulation  du corps professoral  sous la forme de  compensations  professionnelles (nomination, permanence d'emploi et promotion). Le rĂ´le critique des directeurs de dĂ©partment, des doyens, et des cadres supĂ©rieurs dans la crĂ©ation d'une culture institutionnelle qui favoriserait une pĂ©dagogie efficace est Ă©galement perçu comment faisant partie intĂ©grale d'une politique globale d'amĂ©lioration de l'enseignement. L'Ă©tude Ă©value Ă©galement l'importance des activitĂ©s et les structures d'encadrement facilitant le dĂ©veloppement  des  compĂ©tences pĂ©dagogiques des professeurs. Les pratiques ayant pour objectif d'Ă©valuer l'enseignement Ă  des fins de permanence d'emploi et de promotion ont, selon les rĂ©pondants, le moins d'impact sur la qualitĂ© de l'enseignement

    Star Formation and Tidal Encounters with the Low Surface Brightness Galaxy UGC 12695 and Companions

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    We present VLA H I observations of the low surface brightness galaxy UGC 12695 and its two companions, UGC 12687 and a newly discovered dwarf galaxy 2333+1234. UGC 12695 shows solid body rotation but has a very lopsided morphology of the H I disk, with the majority of the H I lying in the southern arm of the galaxy. The H I column density distribution of this very blue, LSB galaxy coincides in detail with its light distribution. Comparing the H I column density of UGC 12695 with the empirical (but not well understood) value of Sigma_c = 10E21 atoms/cm^2 found in, i.e., Skillman's 1986 paper shows the star formation to be a local affair, occurring only in those regions where the column density is above this star formation threshold. The low surface brightness nature of this galaxy could thus be attributed to an insufficient gas surface density, inhibiting star formation on a more global scale. Significantly, though, the Toomre criterion places a much lower critical density on the galaxy (+/-10E20 atoms/cm^2), which is shown by the galaxy's low SFR to not be applicable. Within a projected distance of 300kpc/30kms of UGC 12695 lie two companion galaxies - UGC 12687, a high surface brightness barred spiral galaxy, and 2333+1234, a dwarf galaxy discovered during this investigation. The close proximity of the three galaxies, combined with UGC 12695's extremely blue color and regions of localized starburst and UGC 12687's UV excess bring to mind mutually induced star formation through tidal activity.Comment: 14 pages, 8 figures (2 color), To be published in A.J., May 2000

    Attention Deficit HyperactivityDisorder (ADHD): Survey Report

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    In the spring of 2016, the New Hampshire Pediatric Improvement Partnership (NHPIP) conducted an online survey of NH pediatric and family practice clinicians to understand practice patterns, comfort level, and support needs relative to caring for pediatric patients with Attention Deficit Hyperactivity Disorder (ADHD). Of the clinicians surveyed, 138 responded yielding a 13% response rate

    First Detection of CO in a Low Surface Brightness Galaxy

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    We report on the first attempts at searching for CO in red low surface brightness galaxies, and the first detection of molecular gas in a low surface brightness (mu_B(0)_{obs} > 23 mag arcsec^{-2}) galaxy. Using the IRAM 30m telescope, CO(1-0) and CO(2-1) lines were searched for in four galaxies -- P06-1, P05-5, C05-3, & C04-2. In three of the galaxies no CO was detected, to T_{MB} ~ 1.8mK (at the 3 sigma level). In the fourth galaxy, P06-1, both lines were detected. Comparing our findings with previous studies shows P06-1 to have a molecular-to-atomic mass ratio considerably lower than is predicted using theoretical models based on high surface brightness galaxy studies. This indicates the N(H_2)/(int{T(CO)dv}) conversion factor for low surface brightness galaxies may currently be consistently underestimated by a factor of 3 - 20.Comment: 8 pages, 2 figures, accepted by the ApJ

    Visualizing elements of Sha[3] in genus 2 jacobians

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    Mazur proved that any element xi of order three in the Shafarevich-Tate group of an elliptic curve E over a number field k can be made visible in an abelian surface A in the sense that xi lies in the kernel of the natural homomorphism between the cohomology groups H^1(k,E) -> H^1(k,A). However, the abelian surface in Mazur's construction is almost never a jacobian of a genus 2 curve. In this paper we show that any element of order three in the Shafarevich-Tate group of an elliptic curve over a number field can be visualized in the jacobians of a genus 2 curve. Moreover, we describe how to get explicit models of the genus 2 curves involved.Comment: 12 page

    Further Discoveries of 12CO in Low Surface Brightness Galaxies

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    Using the IRAM 30m telescope we have obtained seven new, deep CO J(1-0) and J(2-1) observations of low surface brightness (LSB) galaxies. Five of the galaxies have no CO detected to extremely low limits (0.1-0.4 K km/s at J(1-0)), while two of the galaxies, UGC 01922 and UGC 12289, have clear detections in both line transitions. When these observations are combined with all previous CO observations taken of LSB systems, we compile a total of 34 observations, in which only 3 galaxies have had detections of their molecular gas. Comparing the LSB galaxies with and without CO detections to a sample of high surface brightness (HSB) galaxies with CO observations indicates that it is primarily the low density of baryonic matter within LSB galaxies which is causing their low CO fluxes. Finally, we note that one of the massive LSB galaxies studied in this project, UGC 06968 (a Malin-1 `cousin'), has upper limits placed on both M_H2 and M_H2/M_HI which are 10-20 times lower than the lowest values found for any galaxy (LSB or HSB) with similar global properties. This may be due to an extremely low temperature and metallicity within UGC 06968, or simply due to the CO distribution within the galaxy being too diffuse to be detected by the IRAM beam.Comment: 18 pages, 8 figures, 4 tables. Accepted by Ap

    Experimental protocol for biodiesel production with isolation of alkenones as coproducts from commercial Isochrysis algal biomass

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    © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Visualized Experiments 112 (2016): e54189, doi:10.3791/54189.The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. Biomass-derived biofuels have gained considerable attention in this regard, however first generation biofuels from edible crops like corn ethanol or soybean biodiesel have generally fallen out of favor. There is thus great interest in the development of methods for the production of liquid fuels from domestic and superior non-edible sources. Here we describe a detailed procedure for the production of a purified biodiesel from the marine microalgae Isochrysis. Additionally, a unique suite of lipids known as polyunsaturated long-chain alkenones are isolated in parallel as potentially valuable coproducts to offset the cost of biodiesel production. Multi-kilogram quantities of Isochrysis are purchased from two commercial sources, one as a wet paste (80% water) that is first dried prior to processing, and the other a dry milled powder (95% dry). Lipids are extracted with hexanes in a Soxhlet apparatus to produce an algal oil ("hexane algal oil") containing both traditional fats (i.e., triglycerides, 46-60% w/w) and alkenones (16-25% w/w). Saponification of the triglycerides in the algal oil allows for separation of the resulting free fatty acids (FFAs) from alkenone-containing neutral lipids. FFAs are then converted to biodiesel (i.e., fatty acid methyl esters, FAMEs) by acid-catalyzed esterification while alkenones are isolated and purified from the neutral lipids by crystallization. We demonstrate that biodiesel from both commercial Isochrysis biomasses have similar but not identical FAME profiles, characterized by elevated polyunsaturated fatty acid contents (approximately 40% w/w). Yields of biodiesel were consistently higher when starting from the Isochrysis wet paste (12% w/w vs. 7% w/w), which can be traced to lower amounts of hexane algal oil obtained from the powdered Isochrysis product.This work was supported by the National Science Foundation (CHE-1151492), the Northwest Advanced Renewables Alliance (fellowship to J. Wilson-Peltier), and through a private donation from friends of WHOI

    Decolorization improves the fuel properties of algal biodiesel from Isochrysis sp.

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    © The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Fuel 179 (2016): 229-234, doi:10.1016/j.fuel.2016.03.061.Results from the comprehensive fuel testing according to American Society for Testing and Materials International (ASTM) standards of an alkenone-free and decolorized biodiesel produced from the industrially grown marine microalgae Isochrysis sp. are presented. Fatty acid methyl ester (FAME) profiles of the non-decolorized and subsequently decolorized biodiesel fuels were nearly identical, yet the fuel properties were remarkably different. Significant positive impacts on the cetane number, kinematic viscosity, and lubricity were observed, indicating a potential deleterious effect of pigments like chlorophylls and pheophytins on these fuel properties. The decolorization process using montmorillonite K10 gave on average 90% mass recovery, and allowed for an otherwise unobtainable cloud point determination. Oxidative stability of the decolorized Isochrysis biodiesel remained well below the minimum prescribed in biodiesel standards due to elevated content of highly polyunsaturated fatty acids, however other values were in the range of those prescribed in the ASTM standards. Overall, decolorization improved the fuel properties of biodiesel from Isochrysis and may provide a path toward improved biodiesel fuels from other algal species.This work was supported by the National Science Foundation (CHE-1151492) and through a private donation from friends of WHOI.2017-03-2

    Spitzer Observations of Low Luminosity Isolated and Low Surface Brightness Galaxies

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    We examine the infrared properties of five low surface brightness galaxies (LSBGs) and compare them with related but higher surface brightness galaxies, using Spitzer Space Telescope images and spectra. All the LSBGs are detected in the 3.6 and 4.5um bands, representing the stellar population. All but one are detected at 5.8 and 8.0um, revealing emission from hot dust and aromatic molecules, though many are faint or point-like at these wavelengths. Detections of LSBGs at the far-infrared wavelengths, 24, 70, and 160um, are varied in morphology and brightness, with only two detections at 160um, resulting in highly varied spectral energy distributions. Consistent with previous expectations for these galaxies, we find that detectable dust components exist for only some LSBGs, with the strength of dust emission dependent on the existence of bright star forming regions. However, the far-infrared emission may be relatively weak compared with normal star-forming galaxies.Comment: 20 pages, 8 figures, accepted to Ap

    Abelian symmetries in multi-Higgs-doublet models

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    N-Higgs doublet models (NHDM) are a popular framework to construct electroweak symmetry breaking mechanisms beyond the Standard model. Usually, one builds an NHDM scalar sector which is invariant under a certain symmetry group. Although several such groups have been used, no general analysis of symmetries possible in the NHDM scalar sector exists. Here, we make the first step towards this goal by classifying the elementary building blocks, namely the abelian symmetry groups, with a special emphasis on finite groups. We describe a strategy that identifies all abelian groups which are realizable as symmetry groups of the NHDM Higgs potential. We consider both the groups of Higgs-family transformations only and the groups which also contain generalized CP transformations. We illustrate this strategy with the examples of 3HDM and 4HDM and prove several statements for arbitrary N.Comment: 33 pages, 2 figures; v2: conjecture 3 is proved and becomes theorem 3, more explanations of the main strategy are added, matches the published versio
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