84,911 research outputs found

    Making Upper Division Mathematics Courses Relevant for Pre-Service Teachers

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    This article addresses the disconnect that in-service and pre-service secondary school teachers feel between the material presented in upper division mathematics courses and high school classroom practice. Two examples are given from an abstract algebra course in which this problem is addressed

    Nonlinear seismic analysis of a reactor structure impact between core components

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    The seismic analysis of the FFTF-PIOTA (Fast Flux Test Facility-Postirradiation Open Test Assembly), subjected to a horizontal DBE (Design Base Earthquake) is presented. The PIOTA is the first in a set of open test assemblies to be designed for the FFTF. Employing the direct method of transient analysis, the governing differential equations describing the motion of the system are set up directly and are implicitly integrated numerically in time. A simple lumped-nass beam model of the FFTF which includes small clearances between core components is used as a "driver" for a fine mesh model of the PIOTA. The nonlinear forces due to the impact of the core components and their effect on the PIOTA are computed

    Gymnostoma tasmanianum sp nov., a fossil Casuarinaceae from the Early Oligocene of Little Rapid River, Tasmania, Australia

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    Int. J Plant Sci. 164(4):629–634. 2003. © 2003 by The University of ChicagoMacrofossils of Casuarinaceae from Early Oligocene sediments at Little Rapid River, Tasmania, are assigned to a new species, Gymnostoma tasmanianum. This is only the second species of fossil Gymnostoma to be formally described and the first species of Gymnostoma to be described from Tasmania. The species is known from both vegetative and reproductive organs. The new taxon is distinguished from other known species by its small stomata, short article length and tooth width, small length:width ratio of articles, glabrous articles, stomata in two to five rows, and teeth elongate with acute apices and sinuses. The fossil record shows that Gymnostoma once had a much wider distribution in Australia than its current occurrence in far north Queensland.Greg Guerin and Robert S. Hil

    Computer program for predicting symmetric jet mixing of compressible flow in jets

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    Finite-difference computer program has been developed for treating mixing of two parallel and compressible air streams; one of them may be supersonic. This development is restricted to symmetric jet mixing in which high-speed jet is located on axis of channel and no provision is made for blowing or suction along channel walls

    Galaxy-CMB and galaxy-galaxy lensing on large scales: sensitivity to primordial non-Gaussianity

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    A convincing detection of primordial non-Gaussianity in the local form of the bispectrum, whose amplitude is given by the fNL parameter, offers a powerful test of inflation. In this paper we calculate the modification of two-point cross-correlation statistics of weak lensing - galaxy-galaxy lensing and galaxy-Cosmic Microwave Background (CMB) cross-correlation - due to fNL. We derive and calculate the covariance matrix of galaxy-galaxy lensing including cosmic variance terms. We focus on large scales (l<100) for which the shape noise of the shear measurement becomes irrelevant and cosmic variance dominates the error budget. For a modest degree of non-Gaussianity, fNL=+/-50, modifications of the galaxy-galaxy lensing signal at the 10% level are seen on scales R~300 Mpc, and grow rapidly toward larger scales as \propto R^2. We also see a clear signature of the baryonic acoustic oscillation feature in the matter power spectrum at ~150 Mpc, which can be measured by next-generation lensing experiments. In addition we can probe the local-form primordial non-Gaussianity in the galaxy-CMB lensing signal by correlating the lensing potential reconstructed from CMB with high-z galaxies. For example, for fNL=+/-50, we find that the galaxy-CMB lensing cross power spectrum is modified by ~10% at l~40, and by a factor of two at l~10, for a population of galaxies at z=2 with a bias of 2. The effect is greater for more highly biased populations at larger z; thus, high-z galaxy surveys cross-correlated with CMB offer a yet another probe of primordial non-Gaussianity.Comment: 21 pages, 30 figure

    Alignment of Alaska’s Educational Programs from Pre-School through Graduate Study: A First Look

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    Too many Alaska students leave formal education unprepared for their next steps in life. Too many drop out of high school; too few high-school graduates go on to post-secondary education; and too few of those who do enroll in post-secondary education graduate in a timely manner. Employers report that a substantial number of young people who enter the work world directly after graduating from high school (or after dropping out) lack the reading, writing, and math skills necessary for many of today’s jobs, even at entry level. Ideally, the various components of the education system would be structured so that as children or young people complete each step, they would be adequately prepared for the next. In practice, this is often not the case. Students arrive at kindergarten and again at college, vocational training, or work unprepared for the challenges they face and without the skills their teachers, professors, or employers expect. Alaska is not alone in these problems, and many states are focusing on alignment as a possible response. Policymakers and others are studying how students progress through the entire education system—from pre-school through college, graduate study, or career training. As defined above, alignment would coordinate the work of institutions providing different levels of education. Educators in K-12 and early childhood programs would agree on what children should know and be able to do when entering kindergarten (or first grade)—and on how those skills and abilities would be taught and assessed. Likewise, employers, institutions of higher education, and K-12 schools would work together to reach similar agreements on what young people need to know to enter the workforce or college. Alignment efforts bring together policymakers and practitioners from all levels of education to identify what needs to be done to achieve this coordination and to oversee the work. The first section of this report looks at alignment of early childhood programs and K-12 education. Why is it important to begin alignment at the level of early childhood education? Research has demonstrated the strong effect of quality early childhood education on later educational outcomes. Among the best-known research is the High/Scope Perry Preschool study, which followed 120 children from the time they attended that preschool in the 1960s, at ages 3 or 4, until they were age 40.1 Schweinhart, et al. (1993) looked at program participants through age 27 and estimated that the program had produced savings to taxpayers of over $7 for each dollar spent. Program participants were less likely to need special education services throughout their school careers, less likely to commit crimes, and less likely to receive welfare—and they alsoearned more and paid higher taxes than non-participants. Other studies have found that children who participate in quality early childhood education programs are less likely to be retained in grade, placed in special education, or drop out of high school (Schweinhart 1994). In Alaska, public early childhood education is limited to federally mandated special education and federally funded (with state supplemental funding) Head Start programs. These programs together enroll about 16% of 3-year-olds and 22% of 4-year-olds in the state. Many more students in urban areas are enrolled in some form of private pre-school. Head start programs exist in more than 75 Alaska communities and are run by 16 different grantees, which have varying degrees of coordination with their local K-12 districts and with each other. The second focus of this report is readiness of Alaska high-school graduates for post-secondary education or work. Alaska’s colleges and universities find that many of their entering students— even those with good grades in high school—aren’t ready for college-level work. Again, national research affirms that Alaska’s problems are not unique. Callan, Finney, Kirst, Usdan, and Venezia (2006) report “The more difficult challenge for students is becoming prepared academically for college coursework. Once students enter college, about half of them learn that they are not prepared for college-level courses. Forty percent of students at four-year institutions and 63 percent at two-year colleges take remedial education. Additionally, high-school students face an incredibly complex system of placement tests and college admissions requirements.” A national survey of 431 employers about workforce readiness found that “When asked to assess new workforce entrants, employers report that many of the new entrants lack skills essential to job success… Over 40 percent (42.4 percent) of employer respondents rate new entrants with a high school diploma as ‘deficient’ in their overall preparation for the entry-level jobs they typically fill. Almost the same percentage (45.6 percent) rate the overall preparation of high school graduate entrants as ‘adequate,’ but almost no one (less than ½ of 1 percent—0.2 percent) rates their overall preparation as ‘excellent.’ ” 2 Anecdotal information from Alaska employers indicates that many young people entering the workforce in Alaska aren’t prepared for work, either. This report brings together available data on the scope of these problems in Alaska and discusses what other states have tried and what we can tell so far about what has worked. We identify areas that need more research and where there may not even be data to conduct research. Finally, we suggest steps the state can undertake now, while conducting research, to fill in the gaps.Avant-Garde Learning Foundation. Shell Exploration and Production Alaska

    Design and development of a theory-informed peer-led falls prevention education programme to translate evidence into practice: A systematic approach

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    Peer-led education has been shown to be an effective approach for raising community-dwelling older adults’ beliefs, knowledge and intention to engage in falls prevention strategies in a recent intervention trial. This article outlines the design and development of the intervention, which was a peer-led falls prevention education programme designed to promote older adult’s motivation to change their behaviour in the area of falls prevention. The elements of the programme that contributed to its efficacy are also described. The programme was designed using a four-step approach and was based on the constructs of a theoretical framework (the COM-B model). Feedback from older adults was also incorporated into the programme development. Programme components developed were a workshop to train older adult peer educators to deliver falls prevention education, a one-hour peer-led falls prevention presentation, and supporting resources to aid programme delivery. A questionnaire measuring older adults’ responses to the presentation was concurrently developed and pilot-tested prior to implementation of the education programme. Finally, resources to monitor and evaluate fidelity at five points in the programme were developed. It was found that seeking older adult consumer involvement, and adopting a theoretical framework-driven approach contributes to effective design and delivery of falls prevention education programmes. This ensured that the programme was acceptable to older adults, feasible to deliver and allowed robust measurement of the effect of the education programme on important behavioural change components

    Leaf cuticular morphology links Platanaceae and Proteaceae

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    Int. J. Plant Sci. 166(5):843–855. © 2005 by The University of Chicago.The leaf cuticular morphology of extant species of Platanus was investigated using light and scanning electron microscopy. All species are shown to possess trichome bases of the same type as those commonly found in Proteaceae. Of particular significance are compound forms that consist of an annular surface scar associated with more than one underlying epidermal cell. These are found on the adaxial leaf surfaces of all species of Platanus and are also clearly evident on the abaxial surface of Platanus orientalis. This type of trichome base is therefore interpreted as the first detected nonreproductive morphological synapomorphy linking Proteaceae and Platanaceae. Also, the laterocytic, sometimes paracytic, or anomocytic arrangement of subsidiary cells in Platanus is distinct from the general state in Proteaceae, which is brachyparacytic and presumably derived. In Bellendena, possibly the most basal genus of extant Proteaceae, subsidiary cell arrangements resemble those of Platanus. These results are discussed with respect to leaf fossil records of Proteales, where it is concluded that the combination of brachyparacytic stomata and compound trichome bases is strong evidence for Proteaceae.Raymond J. Carpenter, Robert S. Hill, and Gregory J. Jorda
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