Blood Parasites of Some Common Texas Birds

Danilwesky observed and recorded avian plasmodia in 1885. Laveran (1891) emphasized the importance of this discovery and suggested that research on bird malaria might help to solve questions on human malaria. Since then, significant papers on bird malaria have been presented by such investigators as R. W. Hegner, W. H. and Lucy G. Taliaferro, C. G. Huff, R. D. Manwell, and R. Hewitt, who studied morphology, physiology, immunity, and transmission of the parasites. Hewitt (1940) made these earlier findings readily available in his monograph on bird malaria

Effect of blockage ratio on drag and pressure distributions for bodies of revolution at transonic speeds

Experimental data were obtained in two wind tunnels for 13 models over a Mach number range from 0.70 to 1.02. Effects of increasing test-section blockage ratio in the transonic region near a Mach number of 1.0 included change in the shape of the drag curves, premature drag creep, delayed drag divergence, and a positive increment of pressures on the model afterbodies. Effects of wall interference were apparent in the data even for a change in blockage ratio from a very low 0.000343 to an even lower 0.000170. Therefore, models having values of blockage ratio of 0.0003 - an order of magnitude below the previously considered safe value of 0.0050 - had significant errors in the drag-coefficient values obtained at speeds near a Mach number of 1.0. Furthermore, the flow relief afforded by slots or perforations in test-section walls - designed according to previously accepted criteria for interference-free subsonic flow - does not appear to be sufficient to avoid significant interference of the walls with the model flow field for Mach numbers very close to 1.0

Nasal Mites of the Mourning Dove

Crossley (1952) described a species of nasal mite, Neonyssus zenaidurae, from the mourning dove (Zenaidura macroura) collected in Texas and Georgia. In his study mites were obtained from 10 of 19 doves examined. Owen (1958) found this species of mite in mourning doves collected in Alabama. He reported an infestation of 4 out of 10 birds (average: 1.5 mites per dove), for one county; and 3 of 10 birds (average: 2.6 mites per dove) for another county. Our method of recovery was similar to that described by Owen. The nasal cavities were separated sagitally, with scissors, from the tip of the beak to the anterior region of the brain. Each half was examined under a wide-field microscope. The parasites when present were found embedded in the mucous secretions and upon the tissues of the nasal cavities. Dissecting needles were used to extricate the specimens and to place them in 70% alcohol. The mites were macerated in 20% KOH for 24 hours to remove adhering tissues. Hoyer\u27s medium is recommended for mounting; if the specimen is mounted in Hoyer\u27s medium and heated soon after the mounting procedures are complete, maceration in KOH is unnecessary

A Search for Trypanosomes in Mourning Doves

Diamond (1954) described a technique for the detection of trypanosomes in geese. We used a similar technique in the search for trypanosomes in each of 64 mourning doves (Zenaidura macroura) collected on September 1-2, 1960, 4 miles west of Celina, Denton County, Texas. The condylar surfaces of the femur, sterilized with alcohol, were removed with sterile scissors, and the marrow, forced from the femur with a hemostat, was collected with a sterile nichrome wire. The inoculum was incubated in the blood agar, broth overlay medium described by Diamond. One sample of the culture was stained on the 6th day of incubation, and a second sample was stained on the 14th day

Journals in the Field of Higher Education: A Racial Analysis

Too often, scholarship regarding the concept of race in the United States is absent from top-tier journals across fields. Yet, at some institutions, faculty, including scholars who explore race, are required to publish in top-tier journals to secure tenure. This article highlights the extent to which journals—of all tiers—within the field of higher education publish articles explicitly highlighting race in the study. The authors used Bray and Major’s article, “Status of Journals in the Field of Higher Education” as the data source for the sample. Using a systematic approach, the authors surveyed journals in the field of higher education to determine the percentage of studies that explicitly focused on race for each of the journals included, using a three-year timeframe. The authors found that individual journals labeled as “top tier mentions” published 14-21% of articles on race. The remainder of the journals included in the study published anywhere from 0-7% of their articles on race. Implications for practice—particularly for tenure-track faculty who consider themselves scholars who explore race—and future research are discussed

An investigation of the existence of a surface water layer on aircraft radomes during simulated flight in heavy precipitation

An experiment to investigate the electromagnetic attenuation effects of an impacting water spray on an aircraft weather radome was conducted in Langley's 4 X 7 m. wind tunnel equipped with a water spray system. Results indicate no significant liquid water film formed at the stagnation point of the radome under the test conditions. However, a water sheath was observed standing away from the radome surface, which could possibly have significant attenuation properties of its own. Due to the lack of fidelity in modeling both the natural environment with the tunnel apparatus and the water sheath, it is recommended that further studies be undertaken to better define the water distribution in the vicinity of the radome and measure its effect on weather radar performance

HST Observations of Giant Arcs: High Resolution Imaging Of Distant Field Galaxies.

We present HST imaging of eight spectroscopically-confirmed giant arcs, pairs and arclets. These objects have all been extensively studied from the ground and we demonstrate the unique advantages of HST imaging in the study of such features by a critical comparison of our data with the previous observations. In particular we present new estimates of the core radii of two clusters (Cl0024+16, A370) determined from lensed features which are identifiable in our HST images. Although our HST observations include both pre- and post-refurbishment images, the depth of the exposures guarantees that the majority of the arcs are detected with diffraction-limited resolution. A number of the objects in our sample are multiply-imaged and we illustrate the ease of identification of such features when working at high resolution. We discuss the morphological and scale information on these distant field galaxies in the light of HST studies of lower redshift samples. We conclude that the dominant population of star-forming galaxies at z=1 is a factor of 1.5-2 times smaller than the similar group in the local field. This implies either a considerable evolution in the sizes of star-forming galaxies within the last $\sim$10 Gyrs or a shift in the relative space densities of massive and dwarf star-forming systems over the same timescale.Comment: 9 pages (no figures), uuencoded, compressed Postscript. Postscript text, tables and figures (803 Kb) available via anonymous ftp in at ftp://ociw.edu//pub/irs/pub/hstarcs.tar.

Evolution since z = 0.5 of the Morphology-Density relation for Clusters of Galaxies

Using traditional morphological classifications of galaxies in 10 intermediate-redshift (z~0.5) clusters observed with WFPC-2 on the Hubble Space Telescope, we derive relations between morphology and local galaxy density similar to that found by Dressler for low-redshift clusters. Taken collectively, the `morphology-density' relationship, M-D, for these more distant, presumably younger clusters is qualitatively similar to that found for the local sample, but a detailed comparison shows two substantial differences: (1) For the clusters in our sample, the M-D relation is strong in centrally concentrated ``regular'' clusters, those with a strong correlation of radius and surface density, but nearly absent for clusters that are less concentrated and irregular, in contrast to the situation for low redshift clusters where a strong relation has been found for both. (2) In every cluster the fraction of elliptical galaxies is as large or larger than in low-redshift clusters, but the S0 fraction is 2-3 times smaller, with a proportional increase of the spiral fraction. Straightforward, though probably not unique, interpretations of these observations are (1) morphological segregation proceeds hierarchically, affecting richer, denser groups of galaxies earlier, and (2) the formation of elliptical galaxies predates the formation of rich clusters, and occurs instead in the loose-group phase or even earlier, but S0's are generated in large numbers only after cluster virialization.Comment: 35 pages, 19 figures, uses psfig. Accepted for publication in Ap