| Records |
| Author |
Rands, S.A.; Cowlishaw, G.; Pettifor, R.A.; Rowcliffe, J.M.; Johnstone, R.A. |
| Title |
Spontaneous emergence of leaders and followers in foraging pairs |
Type |
Journal Article |
| Year |
2003 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
423 |
Issue |
6938 |
Pages |
432-434 |
| Keywords |
Animals; *Energy Metabolism; Food; *Food Chain; *Models, Biological; Motor Activity; *Social Behavior; Time Factors |
| Abstract |
Animals that forage socially often stand to gain from coordination of their behaviour. Yet it is not known how group members reach a consensus on the timing of foraging bouts. Here we demonstrate a simple process by which this may occur. We develop a state-dependent, dynamic game model of foraging by a pair of animals, in which each individual chooses between resting or foraging during a series of consecutive periods, so as to maximize its own individual chances of survival. We find that, if there is an advantage to foraging together, the equilibrium behaviour of both individuals becomes highly synchronized. As a result of this synchronization, differences in the energetic reserves of the two players spontaneously develop, leading them to adopt different behavioural roles. The individual with lower reserves emerges as the 'pace-maker' who determines when the pair should forage, providing a straightforward resolution to the problem of group coordination. Moreover, the strategy that gives rise to this behaviour can be implemented by a simple 'rule of thumb' that requires no detailed knowledge of the state of other individuals. |
| Address |
Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. s.rands@zoo.cam.ac.uk |
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English |
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ISSN  |
0028-0836 |
ISBN |
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Expedition |
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Conference |
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| Notes |
PMID:12761547 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
5138 |
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| Author |
Seyfarth, R.M. |
| Title |
A model of social grooming among adult female monkeys |
Type |
Journal Article |
| Year |
1977 |
Publication |
Journal of Theoretical Biology |
Abbreviated Journal |
J. Theor. Biol. |
| Volume |
65 |
Issue |
4 |
Pages |
671-698 |
| Keywords |
Animals; Behavior, Animal; Female; *Grooming; Haplorhini/*physiology; *Models, Biological; Reproduction; Social Dominance; Time Factors |
| Abstract |
Grooming networks among adult female monkeys exhibit two similar features across a number of different species. High-ranking animals receive more grooming than others, and the majority of grooming occurs between females of adjacent rank. A theoretical model which duplicates these features is presented, and the properties of the model are used to explain the possible causation and function of female grooming behaviour. The model illustrates how relatively simple principles governing the behaviour of individuals may be used to explain more complex aspects of the social structure of non-human primate groups. |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0022-5193 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:406485 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
5259 |
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| Author |
Zentall, T.R. |
| Title |
Support for a theory of memory for event duration must distinguish between test-trial ambiguity and actual memory loss |
Type |
Journal Article |
| Year |
1999 |
Publication |
Journal of the experimental analysis of behavior |
Abbreviated Journal |
J Exp Anal Behav |
| Volume |
72 |
Issue |
3 |
Pages |
467-472 |
| Keywords |
Animals; Behavior, Animal/physiology; Columbidae; Conditioning, Operant/physiology; Discrimination Learning/physiology; Memory/*physiology; *Psychological Theory; Time Factors; Time Perception/physiology |
| Abstract |
Staddon and Higa's (1999) trace-strength theory of timing and memory for event duration can account for pigeons' bias to “choose short” when retention intervals are introduced and to “choose long” when, following training with a fixed retention interval, retention intervals are shortened. However, it does not account for the failure of pigeons to choose short when the intertrial interval is distinct from the retention interval. That finding suggests that stimulus generalization (or ambiguity) between the intertrial interval and the retention interval may result in an effect that has been attributed to memory loss. Such artifacts must be eliminated before a theory of memory for event duration can be adequately tested. |
| Address |
Department of Psychology, University of Kentucky, Lexington 40506, USA. zentall@pop.uky.edu |
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Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0022-5002 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:10605105 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
251 |
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| Author |
Kirkpatrick, J.F.; Liu, I.M.; Turner, J.W.J.; Naugle, R.; Keiper, R. |
| Title |
Long-term effects of porcine zonae pellucidae immunocontraception on ovarian function in feral horses (Equus caballus) |
Type |
Journal Article |
| Year |
1992 |
Publication |
Journal of reproduction and fertility |
Abbreviated Journal |
J Reprod Fertil |
| Volume |
94 |
Issue |
2 |
Pages |
437-444 |
| Keywords |
Animals; Contraception, Immunologic/*veterinary; *Egg Proteins; Estrogens, Conjugated (USP)/urine; Female; Glycoproteins/*pharmacology; Horses/immunology/*physiology; *Membrane Glycoproteins; Ovary/drug effects/*physiology; Progesterone/metabolism; *Receptors, Cell Surface; Swine/immunology; Time Factors; Zona Pellucida/*immunology |
| Abstract |
Ten feral mares free-roaming in Maryland, USA, were inoculated with porcine zonae pellucidae (PZP) protein before the breeding season for three consecutive years (1988-90). Ovarian function was monitored for 51 days during the peak of the breeding season after the third annual PZP inoculation, in seven of these mares and in four untreated control mares, by means of urinary oestrone conjugates and nonspecific progesterone metabolites. None of the ten inoculated mares became pregnant in 1990, compared with 55% of 20 control mares, which included two of the four monitored for ovarian function. Three of the untreated mares demonstrated apparent normal ovarian activity, characterized by preovulatory oestrogen peaks, concurrent progesterone nadirs at ovulation, breeding activity, and luteal-phase progesterone increases after ovulation. Two of the seven monitored PZP-treated mares demonstrated ovulatory cycles that did not result in conception. One was pregnant as a result of conception in 1989 and demonstrated a normal, late-gestation, endocrine profile. The remaining four PZP-treated mares revealed no evidence of ovulation, and urinary oestrogen concentrations were significantly depressed. The experiments indicated that (i) a third consecutive annual PZP booster inoculation is greater than 90% effective in preventing pregnancies in mares and (ii) three consecutive years of PZP treatment may interfere with normal ovarian function as shown by markedly depressed oestrogen secretion. |
| Address |
Deaconess Research Institute, Billings, MT 59102 |
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English |
Summary Language |
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Edition |
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| ISSN |
0022-4251 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:1317449 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
145 |
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| Author |
Lagarde, J.; Kelso, J.A.S.; Peham, C.; Licka, T. |
| Title |
Coordination dynamics of the horse-rider system |
Type |
Journal Article |
| Year |
2005 |
Publication |
Journal of Motor Behavior |
Abbreviated Journal |
J Mot Behav |
| Volume |
37 |
Issue |
6 |
Pages |
418-424 |
| Keywords |
Animals; Biomechanics; *Horses; Humans; Professional Competence; Psychomotor Performance/*physiology; *Sports; Time Factors |
| Abstract |
The authors studied the interaction between rider and horse by measuring their ensemble motions in a trot sequence, comparing 1 expert and 1 novice rider. Whereas the novice's movements displayed transient departures from phase synchrony, the expert's motions were continuously phase-matched with those of the horse. The tight ensemble synchrony between the expert and the horse was accompanied by an increase in the temporal regularity of the oscillations of the trunk of the horse. Observed differences between expert and novice riders indicated that phase synchronization is by no means perfect but requires extended practice. Points of contact between horse and rider may haptically convey effective communication between them. |
| Address |
Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431-771, USA. lagarde@ccs.fau.edu |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0022-2895 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:16280312 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4034 |
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| Author |
Bobbert, M.F.; Santamaria, S. |
| Title |
Contribution of the forelimbs and hindlimbs of the horse to mechanical energy changes in jumping |
Type |
Journal Article |
| Year |
2005 |
Publication |
The Journal of Experimental Biology |
Abbreviated Journal |
J Exp Biol |
| Volume |
208 |
Issue |
2 |
Pages |
249-260 |
| Keywords |
Animals; Biomechanics; Forelimb/*physiology; Hindlimb/*physiology; Horses/*physiology; Locomotion/*physiology; Muscle, Skeletal/*physiology; Time Factors |
| Abstract |
The purpose of the present study was to gain more insight into the contribution of the forelimbs and hindlimbs of the horse to energy changes during the push-off for a jump. For this purpose, we collected kinematic data at 240 Hz from 23 5-year-old Warmbloods (average mass: 595 kg) performing free jumps over a 1.15 m high fence. From these data, we calculated the changes in mechanical energy and the changes in limb length and joint angles. The force carried by the forelimbs and the amount of energy stored was estimated from the distance between elbow and hoof, assuming that this part of the leg behaved as a linear spring. During the forelimb push, the total energy first decreased by 3.2 J kg(-1) and then increased again by 4.2 J kg(-1) to the end of the forelimb push. At the end of the forelimb push, the kinetic energy due to horizontal velocity of the centre of mass was 1.6 J kg(-1) less than at the start, while the effective energy (energy contributing to jump height) was 2.3 J kg(-1) greater. It was investigated to what extent these changes could involve passive spring-like behaviour of the forelimbs. The amount of energy stored and re-utilized in the distal tendons during the forelimb push was estimated to be on average 0.4 J kg(-1) in the trailing forelimb and 0.23 J kg(-1) in the leading forelimb. This means that a considerable amount of energy was first dissipated and subsequently regenerated by muscles, with triceps brachii probably being the most important contributor. During the hindlimb push, the muscles of the leg were primarily producing energy. The total increase in energy was 2.5 J kg(-1) and the peak power output amounted to 71 W kg(-1). |
| Address |
Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit, van der Boechorstraat 9, NL-1081 BT Amsterdam, The Netherlands. MFBobbert@fbw.vu.nl |
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Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0022-0949 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:15634844 |
Approved |
no |
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Serial |
1895 |
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| Author |
Witte, T.H.; Knill, K.; Wilson, A.M. |
| Title |
Determination of peak vertical ground reaction force from duty factor in the horse (Equus caballus) |
Type |
Journal Article |
| Year |
2004 |
Publication |
The Journal of Experimental Biology |
Abbreviated Journal |
J Exp Biol |
| Volume |
207 |
Issue |
Pt 21 |
Pages |
3639-3648 |
| Keywords |
*Acceleration; Animals; Biomechanics; Forelimb/physiology; *Gait; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Telemetry; Time Factors |
| Abstract |
Measurement of peak vertical ground reaction force (GRFz) from multiple limbs simultaneously during high-speed, over-ground locomotion would enhance our understanding of the locomotor mechanics of cursorial animals. Here, we evaluate the accuracy of predicting peak GRFz from duty factor (the proportion of the stride for which the limb is in contact with the ground). Foot-mounted uniaxial accelerometers, combined with UHF FM telemetry, are shown to be practical and accurate for the field measurement of stride timing variables, including duty factor. Direct comparison with the force plate produces a mean error of 2.3 ms and 3.5 ms for the timing of foot on and foot off, respectively, across all gaits. Predictions of peak GRFz from duty factor show mean errors (with positive values indicating an overestimate) of 0.8+/-0.04 N kg(-1) (13%; N=42; mean +/- S.E.M.) at walk, -0.3+/-0.06 N kg(-1) (3%; N=75) at trot, -2.3+/-0.27 N kg(-1) (16%; N=18) for the non-lead limb at canter and +2.1+/-0.7 N kg(-1) (19%; N=9) for the lead limb at canter. The substantial over- and underestimate seen at canter, in the lead and non-lead limbs, respectively, is attributed to the different functions performed by the two limbs in the asymmetrical gaits. The difference in load experienced by the lead and non-lead limbs decreased with increasing speed. |
| Address |
Structure and Motion Lab, The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL9 7TA, UK |
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English |
Summary Language |
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Edition |
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0022-0949 |
ISBN |
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Conference |
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| Notes |
PMID:15371472 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3658 |
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| Author |
Steiner, M. |
| Title |
Biomechanics of tendon healing |
Type |
Journal Article |
| Year |
1982 |
Publication |
Journal of Biomechanics |
Abbreviated Journal |
J Biomech |
| Volume |
15 |
Issue |
12 |
Pages |
951-958 |
| Keywords |
Achilles Tendon/injuries; Animals; Biomechanics; Rats; Tendon Injuries/pathology/*physiopathology; Tensile Strength; Time Factors; *Wound Healing |
| Abstract |
The biomechanics of tendon healing was investigated with unsutured rat achilles tendons. After two, three, and four weeks of healing tensile parameters were assayed with a bone-muscle-tendon-bone preparation elongated to failure at a controlled physiological strain rate. In the third week of healing, stiffness, strength, and energy absorbing capacity all increased approximately 50%. These changes correlated with early fibroplasia. In the fourth week of healing, strength, energy absorbing capacity and elongation to failure all increased relatively more than stiffness. Histologically, larger fibers with better longitudinal alignment developed during this period. At the end of four weeks the tendon's strength was approximately 25% of normal. To summarize, the return of stiffness in a healing tendon preparation correlated with the presence of fibroplasia and the return of other tensile parameters was a function of the amount and organization of the fibroplasia. |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0021-9290 |
ISBN |
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Medium |
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Conference |
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| Notes |
PMID:7166555 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4448 |
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| Author |
Gavrilova, O.; Haluzik, M.; Matsusue, K.; Cutson, J.J.; Johnson, L.; Dietz, K.R.; Nicol, C.J.; Vinson, C.; Gonzalez, F.J.; Reitman, M.L. |
| Title |
Liver peroxisome proliferator-activated receptor gamma contributes to hepatic steatosis, triglyceride clearance, and regulation of body fat mass |
Type |
Journal Article |
| Year |
2003 |
Publication |
The Journal of biological chemistry |
Abbreviated Journal |
J Biol Chem |
| Volume |
278 |
Issue |
36 |
Pages |
34268-34276 |
| Keywords |
Adipose Tissue/*metabolism; Animals; Blotting, Southern; Blotting, Western; Female; Hypoglycemia/genetics; Insulin Resistance/genetics; Lipid Metabolism; Liver/*metabolism; Liver Diseases/genetics/*metabolism; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; RNA/metabolism; Receptors, Cytoplasmic and Nuclear/*genetics/*physiology; Recombination, Genetic; Thiazoles/pharmacology; *Thiazolidinediones; Time Factors; Transcription Factors/*genetics/*physiology; Triglycerides/*metabolism |
| Abstract |
Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor that mediates the antidiabetic effects of thiazolidinediones. PPAR gamma is present in adipose tissue and becomes elevated in fatty livers, but the roles of specific tissues in thiazolidinedione actions are unclear. We studied the function of liver PPAR gamma in both lipoatrophic A-ZIP/F-1 (AZIP) and wild type mice. In AZIP mice, ablation of liver PPAR gamma reduced the hepatic steatosis but worsened the hyperlipidemia, triglyceride clearance, and muscle insulin resistance. Inactivation of AZIP liver PPAR gamma also abolished the hypoglycemic and hypolipidemic effects of rosiglitazone, demonstrating that, in the absence of adipose tissue, the liver is a primary and major site of thiazolidinedione action. In contrast, rosiglitazone remained effective in non-lipoatrophic mice lacking liver PPAR gamma, suggesting that adipose tissue is the major site of thiazolidinedione action in typical mice with adipose tissue. Interestingly, mice without liver PPAR gamma, but with adipose tissue, developed relative fat intolerance, increased adiposity, hyperlipidemia, and insulin resistance. Thus, liver PPAR gamma regulates triglyceride homeostasis, contributing to hepatic steatosis, but protecting other tissues from triglyceride accumulation and insulin resistance. |
| Address |
Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. oksanag@bdg10.niddk.nih.gov |
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Place of Publication |
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Editor |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0021-9258 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:12805374 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
81 |
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| Author |
Crowell-Davis, S.L.; Houpt, K.A.; Carnevale, J. |
| Title |
Feeding and drinking behavior of mares and foals with free access to pasture and water |
Type |
Journal Article |
| Year |
1985 |
Publication |
Journal of animal science |
Abbreviated Journal |
J. Anim Sci. |
| Volume |
60 |
Issue |
4 |
Pages |
883-889 |
| Keywords |
Animals; *Drinking Behavior; *Feeding Behavior; Female; Horses/*physiology; Male; Poaceae; Seasons; Temperature; Time Factors |
| Abstract |
The feeding and drinking behavior of 11 mares and 15 foals living on pasture with free access to water was recorded during 2,340 15-min focal samples taken over 2 yr. Lactating mares on pasture spent about 70% of the day feeding. Foals began feeding on their first day of life. As they grew older, they spent progressively more time feeding, but still spent only 47 +/- 6% of the time feeding by 21 wk of age. Foals fed primarily during the early morning and evening. While grass formed the major proportion of the diet of both foals and mares, they also ate clay, humus, feces, bark, leaves and twigs. Almost all feeding by foals was done while their mothers were feeding. Movement to water sources was frequently, but not invariably, carried out by an entire herd. Frequency (P = .005) but not duration (P greater than .05) of drinking bouts by mares increased as the temperature increased. Frequency was greatest at 30 to 35 C, at which temperature mares drank once every 1.8 h. Frequency of drinking varied with the time of day (P less than .01), being rarest during the early morning (0500 to 0900 h eastern daylight time) and most frequent during the afternoon (1300 to 1700 h). Drinking by foals was very rare. The youngest age at which a foal was observed to drink was 3 wk, and 8 of 15 foals were never observed to drink before weaning. |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0021-8812 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:3988655 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
54 |
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