Knowing Why: The Integration of Theory and Practice

How can the kinds of knowledge needed for administrative practice be most clearly and usefully articulated

Precise Radial Velocities of Polaris: Detection of Amplitude Growth

We present a first results from a long-term program of a radial velocity study of Cepheid Polaris (F7 Ib) aimed to find amplitude and period of pulsations and nature of secondary periodicities. 264 new precise radial velocity measurements were obtained during 2004-2007 with the fiber-fed echelle spectrograph Bohyunsan Observatory Echelle Spectrograph (BOES) of 1.8m telescope at Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We find a pulsational radial velocity amplitude and period of Polaris for three seasons of 2005.183, 2006.360, and 2007.349 as 2K = 2.210 +/- 0.048 km/s, 2K = 2.080 +/- 0.042 km/s, and 2K = 2.406 +/- 0.018 km/s respectively, indicating that the pulsational amplitudes of Polaris that had decayed during the last century is now increasing rapidly. The pulsational period was found to be increasing too. This is the first detection of a historical turnaround of pulsational amplitude change in Cepheids. We clearly find the presence of additional radial velocity variations on a time scale of about 119 days and an amplitude of about +/- 138 m/s, that is quasi-periodic rather than strictly periodic. We do not confirm the presence in our data the variation on a time scale 34-45 days found in earlier radial velocity data obtained in 80's and 90's. We assume that both the 119 day quasi-periodic, noncoherent variations found in our data as well as 34-45 day variations found before can be caused by the 119 day rotation periods of Polaris and by surface inhomogeneities such as single or multiple spot configuration varying with the time.Comment: 15 pages, 7 figures, Accepted for publication in The Astronomical Journa

Response of Breeding Birds in the Great Plains to Low Density Urban Sprawl

Low-density development consumes large tracts of the rural landscape surrounding Great Plains cities. Our objective was to determine how low-density sprawl influences the presence of birds. We used logistic regression models developed for two eastern Great Plains study areas for 1966-1990 to determine the probability of occurrence of bird species on the same areas in 1902. The two areas experienced different levels of low-density urban sprawl from 1902-1990. Birds associated with forests and forest edge are expected to decrease in both areas. Some of these are species of high concern. Dickcissel, a grassland bird, is expected to increase in the area of low sprawl, whereas several bird species associated with intense development, such as the house sparrow, are expected to increase in the area with a greater level of urban sprawl. We conclude that changes in land use and human activity associated with urbanization are influencing plains bird communities

Usable Space Versus Food Quantity in Bobwhite Habitat Management

We studied the response of northern bobwhite (Colinus virginianus) foods (plants and invertebrates), usable space, and populations following thinning and burning on the 60,000-ha pine (Pinus spp.)-grassland restoration area in the Ouachita National Forest, Arkansas, to examine 2 hypotheses commonly used to manage bobwhite habitat: 1) usable space (suitable permanent cover) and 2) food quantity (an element of habitat quality). We estimated invertebrate food abundance using sweep nets and abundance of food-producing plants using herbaceous and woody stem counts. The disk of vulnerability was used to index usable space. We used whistling-male counts to index population response. Relative abundance, mass, and frequency of occurrence of invertebrate foods and richness, density, and frequency of occurrence of bobwhite food-producing plants increased following thinning and fire. Relative abundance of whistling males was greatest in thinned stands 3 growing seasons post-burn and in thinned but unburned stands. We found food supply was related to usable space following treatment. However, food abundance alone did not explain bobwhite population response, whereas, usable space was predictive for bobwhite response. By comparing treated stands with similar usable space but different food quantity, we observed no differences in bobwhite abundance. Neural models suggested bobwhite population response was less sensitive to changes in food supply relative to changes in usable space. We recommend that managers should seek first to provide usable space (suitable permanent cover in low basal area stands), recognizing that adequate food supply will likely be a side effect of management to this end

Fire effects in native plant communities

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Fire prescriptions for restoration and maintenance of native plant communities

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Fire Prescriptions for Maintenance and Restoration of Native Plant Communities

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311.Natural Resource Ecology and Managemen