UK Horse Pasture Evaluation Program

The University of Kentucky is developing stronger ties with the state’s horse industry in the areas of research, extension and teaching. Many horse farms in the bluegrass region are interested in UK’s assistance with pasture evaluation. During the fall of 2005 a team from the UK Forage Extension Program (Ray Smith, Tom Keene, Jesse Morrison, Gabriel Roberts) conducted a pilot project to evaluate horse pastures on 14 central KY farms. One of the focuses of the pilot was the evaluation of pastures for percent tall fescue and the potential of fescue stands to cause fescue toxicity in pregnant broodmares. We have worked closely with Dr. Lowell Bush and his lab in conducting the endophyte infection and ergovaline analyses

Horse Pasture Monitoring Program: Results after Three Years

Since 2001-2002 and the outbreak of Mare Reproductive Loss Syndrome (MLRS) the University of Kentucky has been developing stronger ties with the state’s equine industry. Approximately 30% of the foal crop was lost in the Central Bluegrass region during this period with a devastating impact on the industry. Traditionally, many Thoroughbred farms have functioned as independent entities, but MLRS helped them to realize that the University of Kentucky had tremendous amount of expertise that they could provide in the areas of animal health, forage management, and other areas. Initially, there were many theories as to the cause of MLRS with tall fescue and other potential toxic plant species often mentioned. In the end, MLRS was found to be caused by the accidental ingestion of eastern tent caterpillars, but one of the positive outcomes was that farms realized the need to better understand the composition of their pastures

Entropy and Barrier-Hopping Determine Conformational Viscoelasticity in Single Biomolecules

Biological macromolecules have complex and non-trivial energy landscapes, endowing them a unique conformational adaptability and diversity in function. Hence, understanding the processes of elasticity and dissipation at the nanoscale is important to molecular biology and also emerging fields such as nanotechnology. Here we analyse single molecule fluctuations in an atomic force microscope (AFM) experiment using a generic model of biopolymer viscoelasticity that importantly includes sources of local `internal' conformational dissipation. Comparing two biopolymers, dextran and cellulose, polysaccharides with and without the well-known `chair-to-boat' transition, reveals a signature of this simple conformational change as minima in both the elasticity and internal friction around a characteristic force. A calculation of two-state populations dynamics offers a simple explanation in terms of an elasticity driven by the entropy, and friction by barrier-controlled hopping, of populations on a landscape. The microscopic model, allows quantitative mapping of features of the energy landscape, revealing unexpectedly slow dynamics, suggestive of an underlying roughness to the free energy.Comment: 25 pages, 7 figures, naturemag.bst, modified nature.cls (naturemodified.cls

Modeling the Effects of Human Activity on Katmai Brown Bears (Ursus arctos) through the Use of Survival Analysis

Brown bear-human interactions were observed in 1993, 1995, and 1997 at Kulik River in Katmai National Park and Preserve, Alaska. We analyzed these interactions using survival analysis, creating survival curves for the time that bears remained on the river in the presence, and absence, of human activity. Bear-only survival curves did not vary significantly between years (p = 0.067). Ninety-seven percent of bears left the river within 70 minutes of arrival in all years. Temporal patterns of bear activity were unaffected by the presence of humans as long as the bears did not share river zones with humans (p = 0.062 to p = 0.360). When people and bears did not share river zones, 38.6% (1993), 36.0% (1995), and 37.0% (1997) of bears remained on the river for at least 10 minutes after arrival. In contrast, when people and bears shared river zones, fewer bears remained on the river after the first 10 minutes, with 28.6% (1993), 25.0% (1995), and 32.6% (1997) observed in each year. We conclude that human activity displaced 26.0% (1993), 30.5% (1995), and 12.0% (1997) of the bears using the river, which otherwise would likely have remained longer. Over the three years of study, habituation to human activity may account for observed changes in bears' use of the river.En 1993, 1995 et 1997, des interactions ours brun-être humain ont fait l'objet d'observations à la rivière Kulik, dans la réserve de parc national Katmai, en Alaska. On a analysé ces interactions en ayant recours à l'analyse de survie, créant des courbes de survie pour la durée où les ours restaient à la rivière en présence et en l'absence d'activité humaine. Les courbes de survie pour l'ours seul ne variaient pas sensiblement d'une année à l'autre (p = 0,067). Dans tous les cas, 97% des ours quittaient la rivière dans les 70 minutes suivant leur arrivée. Les schémas de comportement temporel des ours n'étaient pas affectés par la présence d'êtres humains tant que les ours ne partageaient pas les mêmes zones de rivière que les humains (p = 0,062 à p = 0,360). Quand individus et ours ne partageaient pas les mêmes zones de rivière, 38,6% (1993), 36,0% (1995) et 37,0% (1997) des ours restaient à la rivière au moins 10 minutes après leur arrivée. En revanche, quand individus et ours partageaient les zones de rivière, moins d'ours restaient à la rivière au-delà des 10 premières minutes, 28,6% (1993), 25,0% (1995) et 32,6% (1997) ayant été observés chaque année. On conclut que l'activité humaine a délogé 26,0% (1993), 30,5% (1995) et 12,0% (1997) des ours utilisant la rivière, qui, autrement, seraient restés plus longtemps. Au cours des trois années de l'étude, il se pourrait que l'accoutumance à l'activité humaine explique les changements que l'on a observés dans l'utilisation de la rivière par les ours

Horse Pastures: How Much Tall Fescue If Too Much?

Horse owners and managers have known for many years that endophyte infected tall fescue can cause a variety of issues with late term pregnant mares. Research has shown that grazing pure stands induces extreme physiological changes, while grazing pastures completely free of E+ tall fescue is virtually safe. However few pastures are pure stands or completely free of tall fescue. We know that the “danger level” changes over the seasons and that management can greatly reduce the risk of mares grazing infected pastures. Understanding what is “too much” can help us weigh the risks of symptoms to the cost of removal

An Improved Method of Documenting Activity Patterns of Post-Emergence Polar Bears (Ursus maritimus) in Northern Alaska

Throughout their circumpolar range, pregnant female polar bears (Ursus maritimus) create snow dens in which they give birth to altricial cubs. Because polar bear neonates are born in such an undeveloped state, their survival requires a long, undisturbed period of in-den development. To mitigate human impacts on denning bears, it is necessary to understand the chronology of denning, the behaviors of denning bears, and their sensitivity to human activities. Since 2002, we have studied the den emergence behaviors of polar bears in northern Alaska; however, we moved from using on-site observers (2002 – 03) to using autonomous video systems (2005 – 08). Here we compare the duration, activity budgets, and behaviors of polar bears to see whether observation methods affected their activities. Camera systems recorded nearly 10 times the data per den recorded by human observers (526 h/den and 57 h/den respectively). We found no difference between the two study periods in emergence dates, duration at den sites, abandonment dates, or activity budgets for polar bears. We observed a 16-fold reduction in the number of bear-human interactions when using cameras instead of human observers. There was, however, a marked increase in the intensity of response when using cameras (125 m) as compared to observers in blinds (400 m). An understanding of these activity patterns can be used to manage human activities near dens so as to minimize disturbance.À l’échelle de leur aire de répartition circumpolaire, les ourses polaires (Ursus maritimus) en gestation se créent une tanière de neige pour donner naissance à leurs oursons à développement tardif. Puisque les nouveau-nés de l’ourse polaire naissent dans un état si peu développé, leur survie nécessite une longue période de développement non perturbé en tanière. Afin d’atténuer les incidences de l’être humain sur les ours en tanière, il est nécessaire de comprendre la chronologie de la mise bas, les comportements des ours en tanière et leur sensibilité à l’activité humaine. À partir de 2002, nous avons étudié les comportements de sortie des tanières des ours polaires du nord de l’Alaska, tout d’abord au moyen d’observations faites sur place (en 2002 et 2003) et ensuite, au moyen de caméras vidéo autonomes (de 2005 à 2008). Ici, nous comparons la durée, la répartition des activités et les comportements des ours polaires afin de déterminer si les méthodes d’observation ont influencé leurs activités. Les caméras ont enregistré près de dix fois plus de données par tanière que les observateurs humains (526 h/tanière et 57 h/tanière respectivement). Nous n’avons trouvé aucune différence entre les deux périodes à l’étude en ce qui a trait aux dates de sortie, aux durées de séjour en tanière, aux dates d’abandon ou à la répartition des activités des ours polaires. Lorsque nous avons utilisé des caméras par opposition à des observateurs, nous avons dénoté 16 fois moins d’interactions entre les ours et l’être humain. Cependant, nous avons remarqué une augmentation accrue sur le plan de l’intensité de la réponse lorsque nous nous sommes servis de caméras (125 m) comparativement aux observateurs dissimulés (400 m). La compréhension de ces modèles d’activités peut servir à gérer l’activité humaine à proximité des tanières afin de minimiser les perturbations

Interactions of Brown Bears, Ursus arctos, and Gray Wolves, Canis lupus, at Katmai National Park and Preserve, Alaska

We describe several encounters between Brown Bears (Ursus arctos) and Gray Wolves (Canis lupus) that were observed at Katmai National Park and Preserve in southwest Alaska. Katmai Brown Bears and Gray Wolves were observed interacting in a variety of behavioral modes that ranged from agonistic to tolerant. These observations provide additional insight regarding the behavioral plasticity associated with bear-wolf interactions

Vortex motion in axisymmetric piston-cylinder configurations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76950/1/AIAA-8430-329.pd

Post-Den Emergence Behavior of Polar Bears (Ursus maritimus) in Northern Alaska

We observed polar bear (Ursus maritimus) maternity den sites on Alaska’s North Slope in March 2002 and 2003 in an effort to describe bears’ post-den emergence behavior. During 40 sessions spanning 459 h, we observed 8 adults and 14 dependent cubs outside dens for 37.5 h (8.2% of total observation time). There was no significant difference between den emergence dates in 2002 (mean = 15 Mar ± 4.1 d) and 2003 (mean = 21 Mar ± 2.1 d). Following initial den breakout, polar bears remained at their den sites for 1.5 to 14 days (mean = 8.1 ± 5.1 d). The average length of stay in dens between emergent periods was significantly shorter in 2002 (1.79 h) than in 2003 (4.82 h). While outside, adult bears were inactive 49.5% of the time, whereas cubs were inactive 13.4% of the time. We found no significant relationships between den emergence activity and weather. Adult polar bears at den sites subjected to industrial activity exhibited significantly fewer bouts of vigilance than denned bears in undisturbed areas (t = -5.5164, df = 4, p = 0.00). However, the duration of vigilance behaviors at sites near industrial activity was not significantly shorter than at the other sites studied (t = -1.8902, df = 4, p = 0.07). Results for these bears were within the range of findings in other studies of denned polar bears.Nous avons observé des tanières de maternité d’ours polaires (Ursus maritimus) sur le versant nord de l’Alaska aux mois de mars 2002 et 2003 dans le but de décrire le comportement de sortie des ours après leur séjour dans la tanière. Dans le cadre de 40 séances d’observation ayant duré 459 heures, nous avons observé 8 ours adultes et 14 oursons à charge en dehors des tanières pendant 37,5 heures (soit 8,2 % de la durée d’observation totale). Il n’y avait pas de différence importante entre les dates de sortie des tanières en 2002 (moyenne = 15 mars ± 4,1 j) et 2003 (moyenne = 21 mars ± 2,1 j). Après la première sortie de la tanière, les ours polaires restaient à l’emplacement de leur tanière pendant 1,5 à 14 jours (moyenne = 8,1 ± 5.1 j). La longueur moyenne du séjour en tanière entre les périodes de sortie était beaucoup plus courte en 2002 (1,79 h) qu’en 2003 (4,82 h). Une fois sortis, les ours adultes étaient inactifs pendant 49,5 % du temps, tandis que les oursons étaient inactifs pendant 13,4 % du temps. Nous n’avons pas trouvé de lien important entre l’activité une fois sorti de la tanière et le temps qu’il faisait. Les ours polaires adultes à l’emplacement de tanières assujetties à des activités industrielles affichaient beaucoup moins de séquences de vigilance que les ours en tanière des régions tranquilles (t = -5,5164, dl = 4, p = 0,00). Cependant, la durée des comportements de vigilance aux emplacements situés près d’activités industrielles n’était pas beaucoup plus courte qu’aux autres emplacements étudiés (t = - 1,8902, dl = 4, p = 0,07). Les résultats enregistrés pour ces ours tombaient dans l’étendue des constatations découlant d’autres études d’ours polaires en tanière