8,818 research outputs found
Innovative Opportunities for Elementary and Middle School Teachers to Maintain Currency in Mathematics and Science: A Community College-School System Partnership
Since 1992 the Manassas Campus of Northern Virginia Community College – in response to requests from local school systems – has developed four innovative methods of assisting elementary, secondary and middle school teachers to enhance their content knowledge in science and mathematics, as well as integrate curriculum units for classroom presentation. These methods are based on the assumptions that: - While teachers at this level have fundamental understanding of math and science, if they wish to incorporate new concepts or technologies from these fields, graduate level content courses are generally beyond their background level. - Community College faculty can often provide a bridge that connects advanced content in science and mathematics with the applications that can be adapted to elementary/middle school curriculum. - Presenting content to a mixed audience of teachers from K-8 allows teachers to see how content can be adapted to grade levels above and below. - Content delivery methods must be interactive and must be responsive to the multiple demands on these teachers’ time. This requires flexibility in scheduling and course requirements
Veterinarian and His Profession
Let me say to start with, I appreciate being asked to bring you the ideas of a farmer in regard to what we expect of the veterinary profession
3D and 4D printing of metal-organic frameworks
This thesis describes the development of new composite materials by the 3D printing of metal- organic frameworks. The application of these composites in various settings is described.Chapter 1 contains a review of the area of additive manufacturing with a focus on 3D printing and 4D printing. This introduces applications of 3D printing within the chemistry field and wider fields and gives a review of metal-organic frameworks. The application of metal-organic frameworks as catalysts and in 3D printing are described.Chapter 2 describes the experimental work undertaken and the design of the experimental rig for the printing of UV-curable polymer matrices under an inert atmosphere. This chapter contains detailed synthetic methods and procedures used for characterisation equipment used for this work and any characterisation limitations.Chapter 3 contains the work related to the use of magnetically aligned MOFs by the addition of iron. A method for the alignment of iron-rich MOF particles and adsorbed iron oxide nanoparticles in solution by the application of a magnetic field is presented. The alignment of MOF particles with up to 10wt.% iron oxide nanoparticles in a photo-curable polymer resin is demonstrated and the anisotropic optical response of the same is described. The 4D printing of magnetically aligned MOFs in a polymer resin is described.Chapter 4 contains works related to the ability of UiO-66 to catalyse and degrade nerve agent simulant as a novel 4D printed polymer composite. This demonstrates that a macroscopic MOF composite can be used to degrade a nerve agent simulation. A new technique is trialled for the partial calcination of the polymer composite resulting in a micro and meso porous structure with a high specific surface area (633 m²g-¹). This technique and the physical properties investigated of the resulting monolith are described.Chapter 5 presents results of metal-organic framework gels as potential additives for 3D printing and a novel direct-write ink. Metal-organic framework gels of UiO-66, UiO-66-NH₂ and ZIF-8 are fabricated and their ability to act as a rheology modifiers are investigated. Trials are described for the novel 3D printing of metal-organic framework gels and adsorption properties investigated
The abstract boundary---a new approach to singularities of manifolds
A new scheme is proposed for dealing with the problem of singularities in
General Relativity. The proposal is, however, much more general than this. It
can be used to deal with manifolds of any dimension which are endowed with
nothing more than an affine connection, and requires a family \calc\ of curves
satisfying a {\em bounded parameter property} to be specified at the outset.
All affinely parametrised geodesics are usually included in this family, but
different choices of family \calc\ will in general lead to different
singularity structures. Our key notion is the {\em abstract boundary\/} or {\em
-boundary\/} of a manifold, which is defined for any manifold \calm\ and is
independent of both the affine connection and the chosen family \calc\ of
curves. The -boundary is made up of equivalence classes of boundary points
of \calm\ in all possible open embeddings. It is shown that for a
pseudo-Riemannian manifold (\calm,g) with a specified family \calc\ of
curves, the abstract boundary points can then be split up into four main
categories---regular, points at infinity, unapproachable points and
singularities. Precise definitions are also provided for the notions of a {\em
removable singularity} and a {\em directional singularity}. The
pseudo-Riemannian manifold will be said to be singularity-free if its abstract
boundary contains no singularities. The scheme passes a number of tests
required of any theory of singularities. For instance, it is shown that all
compact manifolds are singularity-free, irrespective of the metric and chosen
family \calc.Comment: 40 pages (amslatex) + 5 uuencoded figures (A postscript version is
also available on http://einstein.anu.edu.au/), CMA Maths. Research Report
No. MRR028-9
A Migration Study of \u3ci\u3eStelidota Geminata\u3c/i\u3e (Coleoptera: Nitidulidae)
The strawberry sap beetle, Stelidota geminata (Say), is a major pest of strawberries in the northeastern United States. Further knowledge of the migratory habits of this insect pest can enhance the effectiveness of pest management strategies. This nitidulid was shown to migrate from its overwintering sites to one of its primary reproductive sites, strawberry fields, in late May. The beetle population peaked in the third week in July, 1993 in the strawberry field and then gradually declined. In 1994, the peak, as well as the total population, was much greater than in 1993. Furthermore, S. geminata was concentrated in the transition areas surrounding the strawberry fields prior to the ripening of the fruit
The ecology, biogeography, history and future of two globally important weeds : Cardiospermum halicacabum Linn. and C. grandiflorum Sw.
Members of the balloon vine genus, Cardiospermum, have been extensively moved around the globe as medicinal and horticultural species, two of which are now widespread invasive species; C. grandiflorum and C. halicacabum. A third species, C. corindum, may also have significant invasion potential. However, in some regions the native status of these species is not clear, hampering management. For example, in South Africa it is unknown whether C. halicacabum and C. corindum are native, and this is a major constraint to on-going biological control programmes against invasive C. grandiflorum. We review the geography, biology and ecology of selected members of the genus with an emphasis on the two most widespread invaders, C. halicacabum and C. grandiflorum. Specifically, we use molecular data to reconstruct a phylogeny of the group in order to shed light on the native ranges of C. halicacabum and C. corindum in southern Africa. Phylogenetic analyses indicate that southern African accessions of these species are closely related to South American taxa indicating human-mediated introduction and/or natural long distance dispersal. Then, on a global scale we use species distribution modelling to predict potential suitable climate regions where these species are currently absent. Native range data were used to test the accuracy with which bioclimatic modelling can identify the known invasive ranges of these species. Results show that Cardiospermum species have potential to spread further in already invaded or introduced regions in Australia, Africa and Asia, underlining the importance of resolving taxonomic uncertainties for future management efforts. Bioclimatic modelling predicts Australia to have highly favourable environmental conditions for C. corindum and therefore vigilance against this species should be high. Species distribution modelling showed that native range data over fit predicted suitable ranges, and that factors other than climate influence establishment potential. This review opens the door to better understand the global biogeography of the genus Cardiospermum, with direct implications for management, while also highlighting gaps in current research
Baryons and Dark Matter from the Late Decay of a Supersymmetric Condensate
The possibility that both the baryon asymmetry and dark matter arise from the
late decay of a population of supersymmetric particles is considered. If the
decay takes place below the LSP freeze out temperature, a nonthermal
distribution of LSPs results. With conserved parity these relic LSPs
contribute to the dark matter density. A net asymmetry can exist in the
population of decaying particles if it arises from coherent production along a
supersymmetric flat direction. The asymmetry is transferred to baryons if the
condensate decays through the lowest order nonrenormalizable operators which
couple to odd combinations of standard model particles. This also ensures
at least one LSP per decay. The relic baryon and LSP number densities are then
roughly equal. The ratio of baryon to dark matter densities is then naturally
\Omegab / \OmegaLSP \sim {\cal O}(\mb / \mLSP). The resulting upper limit on
the LSP mass is model dependent but in the range GeV. The
total relic density is related to the order at which the flat direction which
gives rise to the condensate is lifted. The observed density is obtained for a
direction which is lifted by a fourth order Planck scale suppressed operator in
the superpotential.Comment: 14 pages, phyzz
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