13,075 research outputs found
A survey of social studies curricula for kindergarten through grade three in selected communities in the United States.
Thesis (Ed.M.)--Boston Universit
Image Similarity Metrics in Image Registration
Measures of image similarity that inspect the intensity probability distribution of the images have proved extremely popular in image registration applications. The joint entropy of the intensity distributions and the marginal entropies of the individual images are combined to produce properties such as resistance to loss of information in one image and invariance to changes in image overlap during registration. However information theoretic cost functions are largely used empirically. This work attempts to describe image similarity measures within a formal mathematical metric framework. Redefining mutual information as a metric is shown to lead naturally to the standardised variant, normalised mutual information
Improving Techniques to Study Equine Cervical Mucociliary Clearance
Bacterial uterine infections inflict major losses on the equine breeding industry. These infections usually arise from bacteria introduced at breeding. Micro-currents propelled by ciliated cells between the folds of the uterus and cervix have been proposed as a means by which contaminants are expelled. Previous data have shown possible ciliary micro-currents propelling carbon particles, occasionally rotating, through cervical folds. However, adherence to the epithelium may have interfered with movement of carbon in these studies. Therefore, we tested potentially non-adherent substances to reveal ciliary micro-currents on the equine cervix under high magnification video-endoscopy. We hypothesized that polyethylene green microspheres 1 - 5 μm and 50 μm in diameter, would be superior to carbon in revealing micro-currents on the cervical epithelium and that 50 μm hemispherically coated bichromal microspheres would display rotation. A suspension containing these microspheres and carbon was deposited onto the cervix of 5 estrous mares and movement of each type of particle was recorded under high video endoscopy for approximately 10 - 20 minutes. In more than 50% of each video recording the field of view was obscured by camera movement or poor positioning. However, the remainder of the recording contained short segments in which the interactions between the epithelium and particles were observable. All observable segments were then analyzed for the presence or absence of desired (visibility, motion, and rotation) and undesired (aggregation) criteria for each type of particle. Particles were scored for the prevalence of these desired and undesired criteria according to the number of video segments in which they were observed. Data were analyzed by the Kruskal-Wallis test. Backward rotation of bichromal spheres was interpreted as evidence of ciliary activity. Overall, carbon scored equal to or higher than the microspheres, leading to rejection of the hypothesis. Of the microspheres, the bichromal microspheres scored highest overall, but tended to aggregate more than the green microspheres, aggregation being undesirable. Subjective assessment concluded that cervical movement was closely related to respiratory movements of the mare, and that the constantly moving cervical folds helped clear the deposited particles. These data may improve detection of mucociliary clearance in the cervix and uterus and may assist future studies to detect impaired mucociliary clearance in infertile mares
Review: Virtue Information Literacy: Flourishing in an Age of Information Anarchy
Review of Bivens-Tatum, W. (2022). Virtue information literacy: Flourishing in an age of information anarchy. Library Juice Press
Fidelity metrics for virtual environment simulations based on spatial memory awareness states
This paper describes a methodology based on human judgments of memory awareness
states for assessing the simulation fidelity of a virtual environment (VE) in relation
to its real scene counterpart. To demonstrate the distinction between task
performance-based approaches and additional human evaluation of cognitive awareness
states, a photorealistic VE was created. Resulting scenes displayed on a headmounted
display (HMD) with or without head tracking and desktop monitor were
then compared to the real-world task situation they represented, investigating spatial
memory after exposure. Participants described how they completed their spatial
recollections by selecting one of four choices of awareness states after retrieval in
an initial test and a retention test a week after exposure to the environment. These
reflected the level of visual mental imagery involved during retrieval, the familiarity
of the recollection and also included guesses, even if informed. Experimental results
revealed variations in the distribution of participants’ awareness states across conditions
while, in certain cases, task performance failed to reveal any. Experimental
conditions that incorporated head tracking were not associated with visually induced
recollections. Generally, simulation of task performance does not necessarily
lead to simulation of the awareness states involved when completing a memory
task. The general premise of this research focuses on how tasks are achieved,
rather than only on what is achieved. The extent to which judgments of human
memory recall, memory awareness states, and presence in the physical and VE are
similar provides a fidelity metric of the simulation in question
Ray model and ray-wave correspondence in coupled optical microdisks
We introduce a ray model for coupled optical microdisks, in which we select
coupling-efficient rays among the splitting rays. We investigate the resulting
phase-space structure and report island structures arising from the
ray-coupling between the two microdisks. We find the microdisks's refractive
index to influence the phase-space structure and calculate the stability and
decay rates of the islands. Turning to ray-wave correspondence, we find many
resonances to be directly related to the presence of these islands. We study
the relation between the (ray-picture originating) island structures and the
(wave-picture originating) spectral properties of resonances, especially the
leakiness of the resonances which is represented as the imaginary part of the
complex wave vector.Comment: 9 pages, 8 figure
Temperature dependence of surface stress across an order-disorder transition: p(1x2)O/W(110)
Strain relaxations of a p(1x2) ordered oxygen layer on W(110) are measured as
a function of temperature across the disordering transition using low-energy
electron diffraction. The measured strains approach values of 0.027 in the
[1-10] and -0.053 in the [001] direction. On the basis of the measured strain
relaxations, we give quantitative information on temperature-dependent surface
stress using the results of ab initio calculations. From the surface formation
energy for different strains, determined by first-principles calculations, we
estimate that surface stress changes from -1.1 for the ordered phase to -0.2N/m
for the disordered one along [1-10], and from 5.1 to 3.4 N/m along [001].
Moreover, our observation that the strains scale inversely with domain size
confirms that the strain relaxation takes place at the domain boundaries.Comment: 8 pages, 5 figure
Joint Anglo-Soviet biological surveillance exercise on River Dnieper
As one part of an on-going programme concerned with environmental protection as provided for under the terms of a UK/USSR Joint Environmental Protection Agreement signed in London, 21 May 1974, a seminar — ”The elaboration of the scientific basis for monitoring the quality of surface water by hydrobiological indices” was held at Valdai in Russia 12—14 July, 1976. As a continuation of this theme it was agreed that delegations of hydrobiologists from each side should carry out reciprocal visits to carry out comparative field tests on selected systems of biological surveillance in use in the respective countries. In May 1978 a team of British hydrobiologists visited the USSR, under the auspices of the Department of Environment, to carry out joint exercises on the River Dnieper and some tributaries. This paper reports the results of selected methods used by the British side when applied to the conditions found in the River Dnieper
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An industrial profile of wood wool/cement slab manufacture
This profile describes a process developed at the Tropical Products Institute for the manufacture of wood wool/cement clabs. Unlike other commercially available processes this process involves the use of a cement slurry. The process is aimed at conditions in developing countries and significant features include minimum use of machinery, maximum use of labour, flexibility in production to suit market requirements and relatively low capital outlay. For a plant to produce 160 slabs per day, about £50,000 c.i.f. at September 1979 prices, excluding locally available items, is required. At least 28 employment opportunities are created. The profile includes a description of the process, a list of the machinery and equipment, components of capital cost, physical inputs and labour requirement
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