1,648 research outputs found
Genetic Variation in the Midcontinental Population of Sandhill Cranes, \u3ci\u3eGrus Canadensis\u3c/i\u3e
Three subspecies of sandhill crane (Grus canadensis) are recognized in the Midcontinental population, the lesser (Grus c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). Blood samples collected on the population’s primary spring staging area in Nebraska, U.S.A., were used to resolve the genetic relationship among these subspecies. Phylogenetic analysis of 27 G. canadensis, by DNA sequencing of a 675 bp region of the mtDNA, supports the subspecies designations of G. c. canadensis and G. c. tabida. G. c. rowani individuals were intermediate with each of the other two subspecies. Genetic divergence ranged from 6.5 to 14.5% between G. c. canadensis and G. c. tabida, 0.5 to 6.6% within G. c. canadensis, and 0.1 to 6.0% within G. c. tabida. Sufficient DNA for analysis was obtained from shed feathers indicating a source of genetic material that does not require the capture or sacrifice of the birds. Other genetic markers and methods, including satellite telemetry, are required for obtaining detailed information on crane distributions as needed to establish effective management units for the MCP
Lichens of Iller Creek: A checklist for the Iller Creek Unit, a division of Dishman Hills Conservation Area, Spokane Valley, WA
The field of biodiversity documentation encompasses a broad range of research including new species discovery and description, compilation of species present in a given area, and investigation of interspecies interaction. In an era of increasingly devastating and rapid environmental change, documenting biodiversity has become increasingly important. Anthropogenic effects on urban-adjacent natural areas are especially significant, as they can cause numerous, often drastic, responses in ecosystems. Our objective here was to document the lichen biodiversity in a large urban-adjacent protected area: the Iller Creek Unit of the Dishman Hills Conservation Area in Spokane Valley, Washington. This unit encompasses a diversity of habitat types: Ponderosa pine savannah, riparian forests, mixed mesic coniferous forests, and xeric rocky outcrops. Despite conservation efforts, no formal checklists have been assembled for this unit. To compile this checklist, our methods include collecting voucher specimens of all species from each habitat type. The identification process used relevant literature and standard techniques, including thin layer chromatography, chemical spot tests, and microscopy. Identifications were confirmed via DNA barcoding, using the nuclear Internal Transcribed Spacer region. A total of 101 species, spread throughout 55 genera of 27 families were identified. We identified 46 crustose, 49 foliose, and 6 fruticose. Moving forward, we intend to perform comprehensive searches of the less accessible areas without immediate trail access to compile a more complete checklist for use as a baseline for future lichen investigations of the inevitable anthropogenic effects that recreational use and expansion of the city will have on the lichen diversity
Evaluation of Vascular Control Mechanisms Utilizing Video Microscopy of Isolated Resistance Arteries of Rats
This protocol describes the use of in vitro television microscopy to evaluate vascular function in isolated cerebral resistance arteries (and other vessels), and describes techniques for evaluating tissue perfusion using Laser Doppler Flowmetry (LDF) and microvessel density utilizing fluorescently labeled Griffonia simplicifolia (GS1) lectin. Current methods for studying isolated resistance arteries at transmural pressures encountered in vivo and in the absence of parenchymal cell influences provide a critical link between in vivo studies and information gained from molecular reductionist approaches that provide limited insight into integrative responses at the whole animal level. LDF and techniques to selectively identify arterioles and capillaries with fluorescently-labeled GS1 lectin provide practical solutions to enable investigators to extend the knowledge gained from studies of isolated resistance arteries. This paper describes the application of these techniques to gain fundamental knowledge of vascular physiology and pathology in the rat as a general experimental model, and in a variety of specialized genetically engineered designer rat strains that can provide important insight into the influence of specific genes on important vascular phenotypes. Utilizing these valuable experimental approaches in rat strains developed by selective breeding strategies and new technologies for producing gene knockout models in the rat, will expand the rigor of scientific premises developed in knockout mouse models and extend that knowledge to a more relevant animal model, with a well understood physiological background and suitability for physiological studies because of its larger size
Increasing On-Task Behavior Using Teacher Attention Delivered on a Fixed-Time Schedule
The effectiveness of fixed-time delivery of attention to increase the on-task behavior of 2 students in general education was examined. The teacher in this study provided attention to students on a 5-min fixed-time schedule and responded to students in her typical manner between cued intervals. An ABAB withdrawal design was used to test the effects of the intervention. The results of this study indicate that a fixed-time schedule of attention was effective in increasing students’ on-task behavior and decreasing their off-task behavior. Implications of the study for research and practice are discussed
Searching for David within the Goliath of alien woody plant invasions in the Western Cape Province
CITATION: Mills, A. J. & Allen, J. L. 2018. Searching for David within the Goliath of alien woody plant invasions in the Western Cape Province. South African Journal of Science, 114(9/10), Art. #a0285, doi:10.17159/sajs.2018/a0285.The original publication is available at http://sajs.co.zaNo abstract available.https://www.sajs.co.za/article/view/5545Publisher's versio
Evolutionary history of mammalian sucking lice (Phthiraptera: Anoplura)
<p>Abstract</p> <p>Background</p> <p>Sucking lice (Phthiraptera: Anoplura) are obligate, permanent ectoparasites of eutherian mammals, parasitizing members of 12 of the 29 recognized mammalian orders and approximately 20% of all mammalian species. These host specific, blood-sucking insects are morphologically adapted for life on mammals: they are wingless, dorso-ventrally flattened, possess tibio-tarsal claws for clinging to host hair, and have piercing mouthparts for feeding. Although there are more than 540 described species of Anoplura and despite the potential economical and medical implications of sucking louse infestations, this study represents the first attempt to examine higher-level anopluran relationships using molecular data. In this study, we use molecular data to reconstruct the evolutionary history of 65 sucking louse taxa with phylogenetic analyses and compare the results to findings based on morphological data. We also estimate divergence times among anopluran taxa and compare our results to host (mammal) relationships.</p> <p>Results</p> <p>This study represents the first phylogenetic hypothesis of sucking louse relationships using molecular data and we find significant conflict between phylogenies constructed using molecular and morphological data. We also find that multiple families and genera of sucking lice are not monophyletic and that extensive taxonomic revision will be necessary for this group. Based on our divergence dating analyses, sucking lice diversified in the late Cretaceous, approximately 77 Ma, and soon after the Cretaceous-Paleogene boundary (ca. 65 Ma) these lice proliferated rapidly to parasitize multiple mammalian orders and families.</p> <p>Conclusions</p> <p>The diversification time of sucking lice approximately 77 Ma is in agreement with mammalian evolutionary history: all modern mammal orders are hypothesized to have diverged by 75 Ma thus providing suitable habitat for the colonization and radiation of sucking lice. Despite the concordant timing of diversification events early in the association between anoplurans and mammals, there is substantial conflict between the host and parasite phylogenies. This conflict is likely the result of a complex history of host switching and extinction events that occurred throughout the evolutionary association between sucking lice and their mammalian hosts. It is unlikely that there are any ectoparasite groups (including lice) that tracked the early and rapid radiation of eutherian mammals.</p
Thermal tolerance limits of the Chinese mystery snail (\u3ci\u3eBellamya chinensis\u3c/i\u3e): Implications for management
The Chinese mystery snail, Bellamya chinensis (Gray, 1834) is a gastropod native to East Asia and is considered an invasive species in North America where its impacts on native species and ecosystems are not well understood. Scientific literature describing its biology and life history are sparse. Thermal tolerance limits, or the maximum and minimum temperature under which a species can survive, are key to identifying the potential geographical range of a species. The ability of managers to control invasive species is directly impacted by the thermal tolerance limits of a species. We attempted to identify the thermal tolerance limits of B. chinensis in a laboratory setting. Using a random sampling design, we exposed groups of wild-caught B. chinensis to either extreme high or low temperature treatments. We identified the upper temperature tolerance limit as between 40 and 45 °C. This result indicates some hot water management techniques may successfully prevent spread of B. chinensis among waterways. Despite exposing B. chinensis to freezing temperatures for extended periods of time we did not identify a lower temperature limit. Identifying the thermal tolerance limits of this and other invasive species informs predictions of range expansion and identification of potential prevention efforts
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