Material properties of bighorn sheep (Ovis canadensis) horncore bone with implications for energy absorption during impacts

Abstract Founder effects, genetic bottlenecks, and genetic drift in general can lead to low levels of genetic diversity, which can influence the persistence of populations. We examine genetic variation in two populations of desert bighorn sheep Ovis canadensis from New Mexico and Mexico to measure change over time and evaluate the impact of introducing individuals from one population into the other. Over about three generations, the amount of genetic variation in the New Mexico population increased. In contrast, over about two generations the amount of genetic variation in the Mexican population decreased by a great extent compared with an estimate from another Mexican population from which it is primarily descended. The potential reasons for these changes are discussed. In addition, although both populations have low genetic variation, introduction of Mexican rams into the New Mexico population might increase the amount of genetic variation in the New Mexico population. Overall, it appears that management to increase genetic variation might require substantial detailed monitoring and evaluation of ancestry from the different sources and fitness components.

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Infection of Bighorn Sheep (Ovis canadensis) with Myxovirus parainfluenza-3 and Other Respiratory Viruses. Results of Serologic Tests and Culture of Nasal Swabs and Lung Tissue

Bulletin of the Wildlife Disease Association ◽

10.7589/0090-3558-2.2.34 ◽

1966 ◽

Vol 2 (2) ◽

pp. 34-37 ◽

Cited By ~ 2

Author(s):

D. L. HOWE ◽

G. T. WOODS ◽

G. MARQUIS

Keyword(s):

Lung Tissue ◽

Bighorn Sheep ◽

Respiratory Viruses ◽

Ovis Canadensis ◽

Serologic Tests ◽

Nasal Swabs

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Factors influencing heart rate in free-ranging bighorn sheep: a physiological approach to the study of wildlife harassment

Canadian Journal of Zoology ◽

10.1139/z79-265 ◽

1979 ◽

Vol 57 (10) ◽

pp. 2010-2021 ◽

Cited By ~ 69

Author(s):

Robert A. MacArthur ◽

Ronald H. Johnston ◽

Valerius Geist

Keyword(s):

Bighorn Sheep ◽

Ovis Canadensis ◽

Activity Level ◽

Base Line ◽

Vehicular Traffic ◽

Behavioral Reactions ◽

Factors Influencing ◽

Close Range ◽

Physiological Approach ◽

Free Ranging

The telemetered heart rates (HR) of unrestrained female bighorn sheep (Ovis canadensis canadensis) were recorded under various behavioral and environmental circumstances. In all ewes HR varied positively with activity level and inversely with distance to a road traversing the study area. The HR recorded from animals moving at night or through timber by day were higher than during daytime movement across open slopes.Responses to transient stimuli varied greatly. The appearance of free-ranging canids evoked maximal increases in HR in all ewes. Vehicular traffic and aircraft elicited HR responses only at close range (< 200 m). Most (78.1%) HR responses to disturbing stimuli preceded or occurred in the absence of overt behavioral reactions. The HR usually peaked within 60 s of the onset of the response and recovered to predisturbance base line in less than 200 s. The appearance and continued presence (1–10 min) of a human within 50 m of the sheep resulted in a 20% rise in mean HR. The significance of these findings is discussed in relation to the behavior, ecology, and bioenergetics of bighorn sheep.

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Differences in leukocyte differentiation molecule abundances on domestic sheep (Ovis aries) and bighorn sheep (Ovis canadensis) neutrophils identified by flow cytometry

Comparative Immunology Microbiology and Infectious Diseases ◽

10.1016/j.cimid.2016.04.006 ◽

2016 ◽

Vol 46 ◽

pp. 40-46 ◽

Cited By ~ 7

Author(s):

Margaret A. Highland ◽

David A. Schneider ◽

Stephen N. White ◽

Sally A. Madsen-Bouterse ◽

Donald P. Knowles ◽

...

Keyword(s):

Flow Cytometry ◽

Bighorn Sheep ◽

Ovis Canadensis ◽

Ovis Aries ◽

Domestic Sheep

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Computational Modeling and Energy Absorption Behavior of Thin-Walled Tubes with the Kresling Origami Pattern

Journal of the International Association for Shell and Spatial Structures ◽

10.20898/j.iass.2021.008 ◽

2021 ◽

Vol 62 (2) ◽

pp. 71-81

Author(s):

Jiaqiang Li ◽

Yao Chen ◽

Xiaodong Feng ◽

Jian Feng ◽

Pooya Sareh

Keyword(s):

Energy Absorption ◽

Material Properties ◽

Rotation Angle ◽

Programming Model ◽

Mixed Integer ◽

Element Analysis ◽

Cross Sectional ◽

Thin Walled Tube ◽

Absorption Performance ◽

Thin Walled

Origami structures have been widely used in various engineering fields due to their desirable properties such as geometric transformability and high specific energy absorption. Based on the Kresling origami pattern, this study proposes a type of thin-walled origami tube the structural configuration of which is found by a mixed-integer linear programming model. Using finite element analysis, a reasonable configuration of a thin-walled tube with the Kresling pattern is firstly analyzed. Then, the influences of different material properties, the rotation angle of the upper and lower sections of the tube unit, and cross-sectional shapes on the energy absorption behavior of the thin-walled tubes under axial compression are evaluated. The results show that the symmetric thin-walled tube with the Kresling pattern is a reasonable choice for energy absorption purposes. Compared with thin-walled prismatic tubes, the thin-walled tube with the Kresling pattern substantially reduces the initial peak force and the average crushing force, without significantly reducing its energy absorption capacity; moreover, it enters the plastic energy dissipation stage ahead of time, giving it a superior energy absorption performance. Besides, the material properties, rotation angle, and cross-sectional shape have considerable influences on its energy absorption performance. The results provide a basis for the application of the Kresling origami pattern in the design of thin-walled energy-absorbingstructures.

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Linking population performance to nutritional condition in an alpine ungulate

Journal of Mammalogy ◽

10.1093/jmammal/gyaa091 ◽

2020 ◽

Vol 101 (5) ◽

pp. 1244-1256 ◽

Cited By ~ 2

Author(s):

Thomas R Stephenson ◽

David W German ◽

E Frances Cassirer ◽

Daniel P Walsh ◽

Marcus E Blum ◽

...

Keyword(s):

Body Fat ◽

Bighorn Sheep ◽

Nutritional Condition ◽

Ovis Canadensis ◽

Population Increase ◽

Overwinter Survival ◽

Fat Reserves ◽

Adult Females ◽

Free Body

Abstract Bighorn sheep (Ovis canadensis) can live in extremely harsh environments and subsist on submaintenance diets for much of the year. Under these conditions, energy stored as body fat serves as an essential reserve for supplementing dietary intake to meet metabolic demands of survival and reproduction. We developed equations to predict ingesta-free body fat in bighorn sheep using ultrasonography and condition scores in vivo and carcass measurements postmortem. We then used in vivo equations to investigate the relationships between body fat, pregnancy, overwinter survival, and population growth in free-ranging bighorn sheep in California and Nevada. Among 11 subpopulations that included alpine winter residents and migrants, mean ingesta-free body fat of lactating adult females during autumn ranged between 8.8% and 15.0%; mean body fat for nonlactating females ranged from 16.4% to 20.9%. In adult females, ingesta-free body fat > 7.7% during January (early in the second trimester) corresponded with a > 90% probability of pregnancy and ingesta-free body fat > 13.5% during autumn yielded a probability of overwinter survival > 90%. Mean ingesta-free body fat of lactating females in autumn was positively associated with finite rate of population increase (λ) over the subsequent year in bighorn sheep subpopulations that wintered in alpine landscapes. Bighorn sheep with ingesta-free body fat of 26% in autumn and living in alpine environments possess energy reserves sufficient to meet resting metabolism for 83 days on fat reserves alone. We demonstrated that nutritional condition can be a pervasive mechanism underlying demography in bighorn sheep and characterizes the nutritional value of their occupied ranges. Mountain sheep are capital survivors in addition to being capital breeders, and because they inhabit landscapes with extreme seasonal forage scarcity, they also can be fat reserve obligates. Quantifying nutritional condition is essential for understanding the quality of habitats, how it underpins demography, and the proximity of a population to a nutritional threshold.

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