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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Heart and ventilation rate changes during tonic immobility in Ornate Tinamou (Nothoprocta ornata) and High Andean chicken (Gallus gallus) compared to Chilean Tinamou (Nothoprocta perdicaria)

Greder, Cecilia Alexis January 2015 (has links)
Animals can show different responses to fear for example by playing dead when there is no possibility to escape. This response is called tonic immobility (TI) and is a well-established test of fear to evaluate fearfulness. Long durations of TI are generally considered as high levels of fearfulness. Physiological changes observed during tonic immobility suggest that there are changes in the autonomic nervous system (ANS) strongly involved in this process. The main objective for this study was to analyse duration of tonic immobility and heart and ventilation rate during tonic immobility in three different species; domesticated High Andean chickens (Gallus gallus), wild-caught Ornate Tinamous (Nothoprocta ornata) and Chilean Tinamous born in captivity (Nothoprocta perdicaria). In this study needle electrodes were used to measure heart and ventilation rate. The time following induction of tonic immobility (i.e. after holding the bird on its back for 15 s) was characterized by a large increase in heart and ventilation rate. During tonic immobility a progressive decrease in heart and ventilation rate was observed in all species, significant in all cases except for heart rate between start and end of TI in chickens. The duration of TI was significantly longer in Ornate Tinamou compared to Chilean Tinamou and chickens. The same was observed in latency to first head movement. TI is probably controlled by the autonomic nervous system, but a heart rate variability analysis has to be done in order to determine the different relative contributions of the sympathetic and parasympathetic systems in these species.
2

Novel Treatments for Native Forb Restoration in The Great Basin

Fund, Adam J. 01 May 2018 (has links)
Public land management agencies, conservation organizations, and landowners are interested in expanding the diversity of plant species used in rangeland restoration seedings. While the restoration of native grasses and shrubs in the Great Basin has become increasingly successful, restoration of native forbs continues to be problematic. In the Great Basin, soil water availability and soil fungal pathogens are thought to limit to restoration success. During the course of two years, we conducted two field experiments at three sites in the Great Basin that spanned a latitudinal gradient encompassing different precipitation and temperature patterns. In the first experiment, we evaluated two treatments for enhancing native forb restoration – snow fences and N-sulate fabric. In addition, we tested whether multiple fungicide and hydrophobic seed coatings could reduce seed and seedling mortality from soil fungal pathogens. To quantify the effectiveness of treatments, we tracked the fate of sown seeds over four life stages: germination, seedling emergence, establishment, and second-year survival. We found that snow fences and N-sulate fabric had varying degrees of success for increasing seedling emergence or establishment but ultimately did not increase second-year survival. Seed coatings increased seedling emergence but did not increase establishment or second-year survival. In the second experiment, we replicated the first experiment and also measured soil water availability to better understand how snow fences and N-sulate fabric alter soil water availability, and if differences in soil water availability can explain restoration outcomes. While we found that our treatments can increase soil water availability, increased soil water did not consistently result in better restoration outcomes. Snow fences did not benefit any life stage at any site while N-sulate fabric had positive and negative effects on forb restoration depending on the site. Seed coatings increased seedling emergence and establishment at all sites, warranting further research with other forb species. Results from both experiments provide insights for developing new treatments and techniques that can improve native forb restoration in the Great Basin and similar semiarid systems.

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