2,605 research outputs found
The Use of Demolition Wood in Papermaking
The reason for this study came from three factors affecting the paper industry as well as society as a whole. These factors are decreasing landfill space, increasing tipping fees, and increasing demands for alternative fiber sources. In the United States, approximately 9.8 million tons of demolition wood waste is landfilled per year. Increasing governmental regulations which require greater amounts of secondary fiber to be used in papermaking are forcing the industry to consider alternative fiber options. The seven steps in the procedure include: rough wood, wood chips, kraft pulping, fiber refining, screening, handsheets, and testing. The four types of wood involved are a 50 year old house wood, a 100 year old barn wood, a kiln-dried wood, and a red pine green wood. All wood types are pine. The strength test (tensile, burst, tear) revealed that demolition wood fiber is strong enough to be considered as a secondary fiber source. The average value obtained for tear from the demolition wood is 13.7 (mN m2/g). The average values for burst and tensile are 20.3 psi and 4.18 km, respectively. In fact, the values obtained from the old wood are comparable to those obtained by Kleppe for a green wood pine(4). Drawbacks to its use include containment removal, probable bleaching limitations, obtaining the wood, and labor/energy requirements. The resource may best be utilized by having a demolition company deliver the wood, pulp, screen, and refine the wood separately, and have the fibers metered in at know quantities at the blend chest within the paper mill. Ultimately the use of this source becomes a function of society\u27s focus on the green movement and regulations imposed on the industry by the government
The Effects of Sex-Sorted Semen on Southern Dairy Farms
This paper examines the impact of sex-sorted semen adoption on dairy farm level economics. Representative dairies are used to simulate the financial impacts of moving to this new technology. Key economic, financial and herd dynamics will be compared among dairies to show how the uses of sex-sorted semen will affect dairy farms. All seven of the representative dairies that were analyzed sold surplus replacement heifers using sex-sorted semen. The increase use of sex-sorted semen can have very positive impacts on dairies throughout the Southern United States.Dairy production, sex sorted semen, production economics, scenario analysis, Agribusiness, Farm Management, Livestock Production/Industries, Production Economics,
PITFALLS AND POTENTIAL OF SECONDARY DATA ANALYSIS OF THE COUNCIL OF MINISTERS OF EDUCATION, CANADA, NATIONAL ASSESSMENT
Large‐scale scale testing agencies, which are generally located within provincial ministries of education and the Council of Ministers of Education, Canada, have called for secondary data analysis of test and survey data that link contextual and educational factors to student performance. First, the potential of secondary analyses is outlined, followed by discussion of seven pitfalls that need to be addressed to realize this potential in Canada. Greater collaboration between testing agencies and teams of qualified secondary analysis researchers needs to take place to ensure that policy issues relevant to education are addressed in meaningful ways. Key words: large‐scale testing, policy analysis, missing data Les organismes responsables des épreuves communes, qui relèvent généralement des ministères provinciaux de l’Éducation et du Conseil des ministres de lʹÉducation (Canada), ont demandé une analyse de deuxième ordre des données d’épreuves et d’enquêtes reliant des facteurs contextuels et pédagogiques au rendement des élèves. Le potentiel des analyses de deuxième ordre est d’abord présenté ; suit une discussion des sept écueils à éviter pour en tirer profit au Canada. Une meilleure collaboration entre les organismes responsables des tests et les équipes de chercheurs spécialisés dans les analyses de deuxième ordre doit être mise en place afin d’assurer que les questions de politiques en matière d’éducation sont abordées de manière pertinente. Mots clés : épreuves communs, analyse de politiques, données manquantes
STUDENT AND SCHOOL CORRELATES OF MATHEMATICS ACHIEVEMENT: MODELS OF SCHOOL PERFORMANCE BASED ON PAN‐ CANADIAN STUDENT ASSESSMENT
This study explored the relationships between student achievement and student, school and home variables from the pan‐Canadian assessment program administered by the Council of Ministers of Education Canada (CMEC): the School Achievement Indicators Program (SAIP) Mathematics 2001. The study also evaluated the datasets used in relationship to their utility for statistical modeling of school performance. Student beliefs about mathematics are positively related to mathematics achievement for both age groups and for both domains of mathematics. As students’ use of instructional supports (parental assistance with mathematics homework, computers in the mathematics classroom) increases, there is an associated decrease in mathematics scores. Key words: student achievement, school performance, multilevel modeling. Dans cet article, les auteurs explorent les relations entre le rendement scolaire et certaines caractéristiques des élèves, des écoles et de l’environnement familial à partir des données du programme d’évaluation pancanadien du Conseil des ministres de lʹÉducation (Canada) (CMEC), le Programme d’indicateurs du rendement scolaire (PIRS) 2001 en mathématiques. L’étude évalue également les bases de données au regard de leur pertinence pour la modélisation statistique de la performance scolaire. Les auteurs notent une corrélation directe entre les idées que se font les élèves au sujet des mathématiques et le rendement en mathématiques tant pour les groupes d’âge que pour les domaines des mathématiques. Plus les élèves font appel à du soutien pédagogique (aide des parents pour les devoirs de mathématiques, ordinateurs dans les classes de mathématiques), plus les notes en mathématiques diminuent. Mots clés : rendement des élèves, performance scolaire, modélisation à multiples niveaux.
Shared neural substrates of emotionally enhanced perceptual and mnemonic vividness
It is well known that emotionally salient events are remembered more vividly than mundane ones. Our recent research has demonstrated that such memory vividness is due in part to the subjective experience of emotional events as more perceptually vivid, an effect we call emotion-enhanced vividness, or EEV. The present study built on previously reported research in which fMRI data were collected while participants rated relative levels of visual noise overlaid on emotionally salient and neutral images. Ratings of greater EEV were associated with greater activation in the amygdala, visual cortex, and posterior insula. In the present study, we measured BOLD activation that predicted recognition memory vividness for these same images one week later. Results showed that, after controlling for differences between scenes in low-level objective features, hippocampus activation uniquely predicted subsequent memory vividness. In contrast, amygdala and visual cortex regions that were sensitive to EEV were also modulated by subsequent ratings of memory vividness. These findings suggest shared neural substrates for the influence of emotional salience on perceptual and mnemonic vividness, with amygdala and visual cortex activation at encoding contributing to the experience of both perception and subsequent memory. © 2013 Todd, Schmitz, Susskind and Anderson
CONTEXTUAL AND SCHOOL FACTORS ASSOCIATED WITH ACHIEVEMENT ON A HIGH‐STAKES EXAMINATION
This study identified student and school‐level factors associated with student achievement on the Ontario Secondary School Literacy Test (OSSLT), an examination that includes a student questionnaire examining home literacy practices. Linked student and school contextual data enabled the use of hierarchical linear modeling to complete the analyses and examine both student and school level effects. Fourteen student and three school level variables were found to be associated with students’ reading achievement and twelve student and two school level variables were associated with writing. Significant variations between schools were also found for students with individualized education plans, English as a second language, or previous eligibility on the OSSLT. Key words: hierarchical linear modeling, literacy testing, achievement, education factors Dans cette étude, les auteurs ont identifié les facteurs élèves et niveaux scolaires associés au rendement scolaire dans le Test de compétences linguistiques de l’Ontario, un examen qui comprend un questionnaire pour les élèves au sujet des habitudes en matière de littératie à la maison. Des données reliées aux élèves et au contexte scolaire ont permis l’utilisation d’une modélisation linéaire hiérarchique en vue de compléter les analyses et d’étudier les effets quant aux élèves et aux niveaux scolaires. Les auteurs ont établi que quatorze variables ayant trait aux élèves et trois ayant trait aux niveaux scolaires étaient associées au rendement des élèves en matière de lecture et que douze variables ayant trait aux élèves et deux ayant trait aux niveaux scolaires étaient associées à l’écriture. Des écarts importants entre les écoles ont également été notés chez les élèves ayant des programmes pédagogiques sur mesure, inscrits en anglais langue seconde ou déjà admissibles au Test de compétences linguistiques des écoles secondaires de l’Ontario. Mots clés : modélisation linéaire hiérarchique, test de compétences linguistiques, rendement scolaire, facteurs pédagogiques
Psychophysical and neural evidence for emotion-enhanced perceptual vividness
Highly emotional events are associated with vivid flashbulb memories. Here we examine whether the flashbulb metaphor characterizes a previously unknown emotion-enhanced vividness (EEV) during initial perceptual experience. Using a magnitude estimation procedure, human observers estimated the relative magnitude of visual noise overlaid on scenes. After controlling for computational metrics of objective visual salience, emotional salience was associated with decreased noise, or heightened perceptual vividness, demonstrating EEV, which predicted later memory vividness. Event-related potentials revealed a posterior P2 component at ~200 ms that was associated with both increased emotional salience and decreased objective noise levels, consistent with EEV. Blood oxygenation level-dependent response in the lateral occipital complex (LOC), insula, and amygdala predicted online EEV. The LOC and insula represented complimentary influences on EEV, with the amygdala statistically mediating both. These findings indicate that the metaphorical vivid light surrounding emotional memories is embodied directly in perceptual cortices during initial experience, supported by cortico-limbic interactions. © 2012 the authors
Current velocity and catch efficiency in sampling settlement-stage larvae of coral-reef fishes
Light traps and channel nets are fixed-position devices that involve active and passive sampling, respectively, in the collection of settlement-stage larvae of coral-reef fishes. We compared the abundance, taxonomic composition, and size of such larvae caught by each device deployed simultaneously near two sites that differed substantially in current velocity. Light traps were more selective taxonomically, and the two sampling devices differed significantly in the abundance but not size of taxa caught. Most importantly, light traps and channel nets differed greatly in their catch efficiency between sites: light traps were ineffective in collecting larvae at the relatively high-current site, and channel nets were less efficient in collecting larvae at the low-current site. Use of only one of these sampling methods would clearly result in biased and inaccurate estimates of the spatial variation in larval abundance among locations that differ in current velocity. When selecting a larval sampling device, one must consider not only how well a particular taxon may be represented, but also the environmental conditions under which the device will be deployed
Correlation between muonic levels and nuclear structure in muonic atoms
A method that deals with the nucleons and the muon unitedly is employed to
investigate the muonic lead, with which the correlation between the muon and
nucleus can be studied distinctly. A "kink" appears in the muonic isotope shift
at a neutron magic number where the nuclear shell structure plays a key role.
This behavior may have very important implications for the experimentally
probing the shell structure of the nuclei far away from the -stable
line. We investigate the variations of the nuclear structure due to the
interaction with the muon in the muonic atom and find that the nuclear
structure remains basically unaltered. Therefore, the muon is a clean and
reliable probe for studying the nuclear structure. In addition, a correction
that the muon-induced slight change in the proton density distribution in turn
shifts the muonic levels is investigated. This correction to muonic level is as
important as the Lamb shift and high order vacuum polarization correction, but
is larger than anomalous magnetic moment and electron shielding correction.Comment: 2 figure
Verification of Unstructured Grid Adaptation Components
Adaptive unstructured grid techniques have made limited impact on production analysis workflows where the control of discretization error is critical to obtaining reliable simulation results. Recent progress has matured a number of independent implementations of flow solvers, error estimation methods, and anisotropic grid adaptation mechanics. Known differences and previously unknown differences in grid adaptation components and their integrated processes are identified here for study. Unstructured grid adaptation tools are verified using analytic functions and the Code Comparison Principle. Three analytic functions with different smoothness properties are adapted to show the impact of smoothness on implementation differences. A scalar advection-diffusion problem with an analytic solution that models a boundary layer is adapted to test individual grid adaptation components. Laminar flow over a delta wing and turbulent flow over an ONERA M6 wing are verified with multiple, independent grid adaptation procedures to show consistent convergence to fine-grid forces and a moment. The scalar problems illustrate known differences in a grid adaptation component implementation and a previously unknown interaction between components. The wing adaptation cases in the current study document a clear improvement to existing grid adaptation procedures. The stage is set for the infusion of verified grid adaptation into production fluid flow simulations
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