1,008 research outputs found
Projects to stimulate appreciation of literature in secondary schools
Progressive educators have realized the crying need for schooling that will carry over into purposeful living in later life. After much experimentation and serious study, the conclusion has been made that the individual differences and interests of the students have often defeated successful teaching of literature by the old method. The use of projects is one of the most valuable ways of according careful consideration and attention to these individual differences and interests in the teaching of literature.
This study of the project in secondary literature courses has been made through visits to schools, interviews with teachers and students, questionnaires, examinations, magazines, and books. It is the object of this thesis to discuss the nature of the project, its uses, and various forms as these are advantageous in the teaching of literature in the secondary schools
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Some Effects of Electrostatic Fields on Brain Activity in Rats
This study concerned the effects of short-term exposures to continuous (10 kv/meter) and pulsed 20 volts at 640 cps/100 msecs) electrostatic fields on the EEG recorded from external electrodes and hypothalamic activity recorded from implanted electrodes in rats. Each experiment lasted at least 90 minutes. The total energies of the waveforms recorded were integrated and printed out for plotting and analysis. Besides the brain activity, the ECG, respiration, and temperature of the animals were also monitored before, during,and after exposure to the electrostatic fields
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A chromosome analysis of five cell lines from four species of salmonid fishes
Four cell lines derived from embryonic tissues of four species
of salmonid fishes, and one from a hepatoma in rainbow trout have
been established in this laboratory. The species represented are
chinook, coho, and sockeye salmon; and steelhead and rainbow trout.
All of these lines have been cultivated for approximately three years.
A chromosome analysis was performed on these cell lines and
two primary cell cultures from embryonic tissues of chinook and coho
salmon. Each analysis consisted of two parts, chromosome preparation
and chromosome characterization.
Chromosome preparation involved exposing a growing culture to
colchicine. The cells were harvested, flattened, expanded, fixed,
and stained.
Chromosomes were characterized by selecting 100 metaphase cells from stained preparations of each cell culture, and determining
the number of chromosomes per cell and each chromosome's
morphology.
At the time of analysis, the cell lines were about two years old,
and the primary cultures were three to six weeks old. The modal
numbers and ranges of chromosomes per cell for the five cell lines
were as follows: chinook salmon line (TC-114), mode 71, range 18
to 190; coho salmon line (TC-119), mode 71, range 57 to 173; sockeye
salmon line (SeE), mode 56, range 51 to 101; steelhead trout line
(TC-137), mode 62, range 58 to 126; and rainbow trout line (TC-149),
modes 54 and 60, range 18 to 144. Similar distributions for the two
primary cell cultures were the following: chinook salmon culture,
mode 68, range 35 to 172; and coho primary culture, mode 60, range
58 to 119.
These data indicate that the chinook and coho salmon, and the
steelhead and rainbow trout hepatoma lines were heteroploid. Also,
the sockeye salmon line, and coho and chinook salmon primary cultures
had normal diploid chromosome constitutions.
All seven cell cultures showed ranges and/or distributions of
chromosome numbers per cell that were greater than found in normal
in vivo cells.
Chromosome morphology was determined by classifying each
counted chromosome as either metacentric or telocentric. The morphology of the chromosomes in each sample of 100 cells was represented
by the average ratio of telocentrics to metacentrics per cell.
The sockeye salmon and rainbow trout cell lines and the chinook primary
cell culture had ratios similar to those reported for these
species. The other cultures had ratios which differed slightly from
those characteristic of the species
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The Oregon sockeye salmon virus : A. Biophysical biochemical characteristics B. antigenic relationship to two other salmonid viruses
The Oregon sockeye salmon virus (OSV) was isolated from
diseased sockeye salmon (Oncorhynchus nerka) fingerlings in 1958
by J. L. Fryer. Experimentation performed prior to the research
reported herein indicated that the OSV contained essential lipids, was
100 to 300 mμ in size, and possessed RNA (presumptively identified
by 5-bromodeoxyuridine treatment of OSV-infected cell cultures).
In the present investigation, OSV was propagated in one of two
cell lines derived from the embryonic tissues of either sockeye or
chinook (O. tshawytscha) salmon. Infectious cell culture medium
was purified by differential centrifugation alone, or in combination
with RNase and DNase treatment, and rate-zonal sucrose gradient
centrifugation.
OSV suspensions had a propensity for forming viral aggregates
during differential centrifugation, presumably caused by pelleting
virions in the presence of host cell debris and serum proteins.
Partially purified virus suspensions were fractionated into four visible
bands by rate-zonal or isopycnic sucrose gradient centrifugation.
Most virus infectivity was detected in two closely associated bands in
the middle of the gradient. Evidence suggested that the more dense,
faster sedimenting band contained infectious virus and the other band
was composed of incomplete, noninfectious virus particles. The
sucrose density of the virus band was determined to be 1.16 g/cm³.
The two other visible bands, one above and one below the presumably
heterogeneous virus band, were considered to represent nonviral
material complexed with varying amounts of virus. Large amounts of
virus infectivity were lost either during sucrose gradient centrifugation
or when sucrose concentrations were reduced in gradient fractions
by dilution and/or dialysis.
Purified suspensions of OSV were treated with hot perchloric
acid in order to extract viral nucleic acid. RNA and DNA concentrations
in the extracts were estimated with the orcinol and diphenylamine
tests. Concentrations of RNA were at least 14 times higher
than those of DNA. Viral nucleic acid was also extracted from
purified ³²P-labeled OSV suspensions by the phenol method at 4°C.
Spectral properties of the resulting nucleic acid solutions indicated
that they contained relatively large amounts of protein. Viral nuclei acid formed a single band at densities of 1.58 to 1.59 g/cm³ when
subjected to isopycnic cesium sulfate gradient centrifugation. Rate-zonal glycerol gradient centrifugation of ³²P-OSV nucleic acid
resulted in the formation of a diffuse band of radioactivity with its
peak at 26 S and a pronounced shoulder at 37 S. RNase treatment of
aliquots from glycerol gradient fractions reduced all trichloroacetic
acid-precipitable ³²P-radioactivity by 85 to 97%. Anion exchange
chromatography of alkaline-hydrolyzed ³²P-viral nucleic acid was
used to determine its base composition. Percentage base compositions
were cytidylic acid, 25.8 ± 0.6%; adenylic acid, 23.0 ± 0.8%; uridylic acid, 27.7 ± 0.6%; and guanylic acid, 23.4 ± 0.4%. The fore-mentioned
experimental data demonstrate that the OSV virion contains
single-stranded RNA.
Rabbit-immune sera were produced against OSV, infectious
hematopoietic necrosis (IHN) virus, and Sacramento River chinook
disease (SRCD) virus. The latter two viruses were isolated from
diseased sockeye and chinook salmon, respectively. Differentially
centrifuged virus suspensions, containing 5.0 x 10⁸ to 2.0 x 10⁹
TCID₅₀/ml, were injected undiluted or emulsified with Freund's
adjuvant into rabbits. The antigenic relationship between OSV, IHN
virus, and SRCD virus was investigated using cross plaque neutralization
tests with each antiserum versus the three viruses. Fifty percent
plaque neutralization end points determined in these tests
indicated that all three viruses were antigenically related, with OSV
and IHN virus being indistinguishable.
Differentially centrifuged, glutaraldehyde-fixed and unfixed
suspensions of OSV were stained with phosphotungstic acid and
examined with an electron microscope. The most numerous type of
particle in fixed preparations was bullet-shaped with average dimensions
of 98 x 166 mμ.. However, the most abundant type of particle
in unfixed suspensions consisted of two roughly spherical (80 mμ in
diameter), closely associated particles. The discrepancy between
the appearance of fixed and unfixed OSV suspensions was not experimentally
resolved
The HI and Ionized Gas Disk of the Seyfert Galaxy NGC 1144 = Arp 118: A Violently Interacting Galaxy with Peculiar Kinematics
We present observations of the distribution and kinematics of neutral and
ionized gas in NGC 1144, a galaxy that forms part of the Arp 118 system.
Ionized gas is present over a huge spread in velocity (1100 km/s) in the disk
of NGC 1144, but HI emission is detected over only 1/3 of this velocity range,
in an area that corresponds to the NW half of the disk. In the nuclear region
of NGC 1144, a jump in velocity in the ionized gas component of 600 km/s is
observed. Faint, narrow HI absorption lines are also detected against radio
sources in the SE part of the disk of NGC 1144, which includes regions of
massive star formation and a Seyfert nucleus. The peculiar HI distribution,
which is concentrated in the NW disk, seems to be the inverse of the molecular
distribution which is concentrated in the SE disk. Although this may partly be
the result of the destruction of HI clouds in the SE disk, there is
circumstantial evidence that the entire HI emission spectrum of NGC 1144 is
affected by a deep nuclear absorption line covering a range of 600 km/s, and is
likely blueshifted with respect to the nucleus. In this picture, a high
column-density HI stream is associated with the nuclear ionized gas velocity
discontinuity, and the absorption effectively masks any HI emission that would
be present in the SE disk of NGC 1144.Comment: manuscript, arp118.ps: 28 pages; 1 Table: arp118.tab1.ps; 16 Figures:
arp118.fig1-16.ps; Accepted to Ap
A tool for teaching principles of image metadata generation
Proceedings of the 6th ACM/IEEE-CS Joint Conference on Digital Libraries, JCDL '06: p. 341.We developed a simple web-based prototype to familiarize
students with digital library tools. To assist the students with the
indexing task, the prototype provided basic functionalities,
including metadata input form, photo search interface. The
students generally expressed a positive feedback toward the use
of digital library tools in their image indexing project
Non-Newtonian fluid flow through three-dimensional disordered porous media
We investigate the flow of various non-Newtonian fluids through
three-dimensional disordered porous media by direct numerical simulation of
momentum transport and continuity equations. Remarkably, our results for
power-law (PL) fluids indicate that the flow, when quantified in terms of a
properly modified permeability-like index and Reynolds number, can be
successfully described by a single (universal) curve over a broad range of
Reynolds conditions and power-law exponents. We also study the flow behavior of
Bingham fluids described in terms of the Herschel-Bulkley model. In this case,
our simulations reveal that the interplay of ({\it i}) the disordered geometry
of the pore space, ({\it ii}) the fluid rheological properties, and ({\it iii})
the inertial effects on the flow is responsible for a substantial enhancement
of the macroscopic hydraulic conductance of the system at intermediate Reynolds
conditions. This anomalous condition of ``enhanced transport'' represents a
novel feature for flow in porous materials.Comment: 5 pages, 5 figures. This article appears also in Physical Review
Letters 103 194502 (2009
Quantification of habitat fragmentation reveals extinction risk in terrestrial mammals
Although habitat fragmentation is often assumed to be a primary driver of extinction, global patterns of fragmentation and its relationship to extinction risk have not been consistently quantified for any major animal taxon. We developed high-resolution habitat fragmentation models and used phylogenetic comparative methods to quantify the effects of habitat fragmentation on the world's terrestrial mammals, including 4,018 species across 26 taxonomic Orders. Results demonstrate that species with more fragmentation are at greater risk of extinction, even after accounting for the effects of key macroecological predictors, such as body size and geographic range size. Species with higher fragmentation had smaller ranges and a lower proportion of high-suitability habitat within their range, andmost high-suitability habitat occurred outside of protected areas, further elevating extinction risk. Our models provide a quantitative evaluation of extinction risk assessments for species, allow for identification of emerging threats in species not classified as threatened, and provide maps of global hotspots of fragmentation for the world's terrestrial mammals. Quantification of habitat fragmentation will help guide threat assessment and strategic priorities for global mammal conservation
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