| Records |
| 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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English |
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0021-9258 |
ISBN |
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| Notes |
PMID:12805374 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
81 |
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| Author |
McGuigan, M.P.; Wilson, A.M. |
| Title |
The effect of gait and digital flexor muscle activation on limb compliance in the forelimb of the horse Equus caballus |
Type |
Journal Article |
| Year |
2003 |
Publication |
The Journal of Experimental Biology |
Abbreviated Journal |
J Exp Biol |
| Volume |
206 |
Issue |
Pt 8 |
Pages |
1325-1336 |
| Keywords |
Animals; Biomechanics; Forelimb/anatomy & histology/*physiology; Gait/*physiology; Horses/anatomy & histology/*physiology; Muscle Contraction/*physiology; Running |
| Abstract |
A horse's legs are compressed during the stance phase, storing and then returning elastic strain energy in spring-like muscle-tendon units. The arrangement of the muscle-tendon units around the lever-like joints means that as the leg shortens the muscle-tendon units are stretched. The forelimb anatomy means that the leg can be conceptually divided into two springs: the proximal spring, from the scapula to the elbow, and the distal spring, from the elbow to the foot. In this paper we report the results of a series of experiments testing the hypothesis that there is minimal scope for muscle contraction in either spring to adjust limb compliance. Firstly, we demonstrate that the distal, passive leg spring changes length by 127 mm (range 106-128 mm) at gallop and the proximal spring by 12 mm (9-15 mm). Secondly, we demonstrate that there is a linear relationship between limb force and metacarpo-phalangeal (MCP) joint angle that is minimally influenced by digital flexor muscle activation in vitro or as a function of gait in vivo. Finally, we determined the relationship between MCP joint angle and vertical ground-reaction force at trot and then predicted the forelimb peak vertical ground-reaction force during a 12 m s(-1) gallop on a treadmill. These were 12.79 N kg(-1) body mass (BM) (range 12.07-13.73 N kg(-1) BM) for the lead forelimb and 15.23 N kg(-1) BM (13.51-17.10 N kg(-1) BM) for the non-lead forelimb. |
| Address |
Structure and Motion Laboratory, Veterinary Basic Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, UK. m.p.mcguigan@leeds.ac.uk |
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English |
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0022-0949 |
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| Notes |
PMID:12624168 |
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no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3655 |
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| Author |
Hoang, L.; Maity, H.; Krishna, M.M.G.; Lin, Y.; Englander, S.W. |
| Title |
Folding units govern the cytochrome c alkaline transition |
Type |
Journal Article |
| Year |
2003 |
Publication |
Journal of Molecular Biology |
Abbreviated Journal |
J Mol Biol |
| Volume |
331 |
Issue |
1 |
Pages |
37-43 |
| Keywords |
Animals; Cytochrome c Group/*chemistry; Horses; Hydrogen/chemistry; Hydrogen-Ion Concentration; Kinetics; Models, Molecular; *Protein Folding; Protein Structure, Tertiary; Spectrum Analysis; Titrimetry |
| Abstract |
The alkaline transition of cytochrome c is a model for protein structural switching in which the normal heme ligand is replaced by another group. Stopped flow data following a jump to high pH detect two slow kinetic phases, suggesting two rate-limiting structure changes. Results described here indicate that these events are controlled by the same structural unfolding reactions that account for the first two steps in the reversible unfolding pathway of cytochrome c. These and other results show that the cooperative folding-unfolding behavior of protein foldons can account for a variety of functional activities in addition to determining folding pathways. |
| Address |
Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6059, USA. lhoang@mail.upenn.edu |
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English |
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| ISSN |
0022-2836 |
ISBN |
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Medium |
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Conference |
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| Notes |
PMID:12875834 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3781 |
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| Author |
Mettke-Hofmann, C.; Gwinner, E. |
| Title |
Long-term memory for a life on the move |
Type |
Journal Article |
| Year |
2003 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
| Volume |
100 |
Issue |
10 |
Pages |
5863-5866 |
| Keywords |
Animals; Germany; Israel; Memory/*physiology; Models, Biological; Periodicity; Songbirds/*physiology |
| Abstract |
Evidence is accumulating that cognitive abilities are shaped by the specific ecological conditions to which animals are exposed. Long-distance migratory birds may provide a striking example of this. Field observations have shown that, at least in some species, a substantial proportion of individuals return to the same breeding, wintering, and stopover sites in successive years. This observation suggests that migrants have evolved special cognitive abilities that enable them to accomplish these feats. Here we show that memory of a particular feeding site persisted for at least 12 months in a long-distance migrant, whereas a closely related nonmigrant could remember such a site for only 2 weeks. Thus, it seems that the migratory lifestyle has influenced the learning and memorizing capacities of migratory birds. These results build a bridge between field observations suggesting special memorization feats of migratory birds and previous neuroanatomical results from the same two species indicating an increase in relative hippocampal size from the first to the second year of life in the migrant but not in the nonmigrant. |
| Address |
Max Planck Research Centre for Ornithology, Department of Biological Rhythms and Behaviour, Von-der-Tann-Strasse 7, 82346 Andechs, Germany. mettke-hofmann@erl.ornithol.mpg.de |
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English |
Summary Language |
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Edition |
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| ISSN |
0027-8424 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:12719527 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
511 |
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| Author |
Lee, R.D. |
| Title |
Rethinking the evolutionary theory of aging: transfers, not births, shape senescence in social species |
Type |
Journal Article |
| Year |
2003 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc Natl Acad Sci U S A |
| Volume |
100 |
Issue |
16 |
Pages |
9637-9642 |
| Keywords |
Adaptation, Physiological; *Aging; Animals; *Biological Evolution; Demography; Economics; Environment; Fertility; Humans; Life Expectancy; Longevity; Models, Theoretical; Parturition; Population Dynamics; Population Growth; Reproduction |
| Abstract |
The classic evolutionary theory of aging explains why mortality rises with age: as individuals grow older, less lifetime fertility remains, so continued survival contributes less to reproductive fitness. However, successful reproduction often involves intergenerational transfers as well as fertility. In the formal theory offered here, age-specific selective pressure on mortality depends on a weighted average of remaining fertility (the classic effect) and remaining intergenerational transfers to be made to others. For species at the optimal quantity-investment tradeoff for offspring, only the transfer effect shapes mortality, explaining postreproductive survival and why juvenile mortality declines with age. It also explains the evolution of lower fertility, longer life, and increased investments in offspring. |
| Address |
Department of Demography, University of California, 2232 Piedmont Avenue, Berkeley, CA 94720-2120, USA. rlee@demog.berkeley.edu |
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English |
Summary Language |
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0027-8424 |
ISBN |
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| Notes |
PMID:12878733 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
5465 |
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| Author |
Johnson, D.D.P.; Stopka, P.; Knights, S. |
| Title |
Sociology: The puzzle of human cooperation |
Type |
Journal Article |
| Year |
2003 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
421 |
Issue |
6926 |
Pages |
911-2; discussion 912 |
| Keywords |
Altruism; *Cooperative Behavior; Evolution; Humans; *Models, Biological; Punishment; Reward; Risk |
| Abstract |
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| Address |
Olin Institute for Strategic Studies, Harvard University, Cambridge, Massachusetts 02138, USA. dominic@post.harvard.edu |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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Medium |
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Conference |
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| Notes |
PMID:12606989 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
467 |
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| Author |
Conradt, L.; Roper, T.J. |
| Title |
Group decision-making in animals |
Type |
Journal Article |
| Year |
2003 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
421 |
Issue |
6919 |
Pages |
155-158 |
| Keywords |
Animals; Behavior, Animal/*physiology; *Decision Making; Democracy; Group Processes; *Models, Biological; Population Density; Social Behavior |
| Abstract |
Groups of animals often need to make communal decisions, for example about which activities to perform, when to perform them and which direction to travel in; however, little is known about how they do so. Here, we model the fitness consequences of two possible decision-making mechanisms: 'despotism' and 'democracy'. We show that under most conditions, the costs to subordinate group members, and to the group as a whole, are considerably higher for despotic than for democratic decisions. Even when the despot is the most experienced group member, it only pays other members to accept its decision when group size is small and the difference in information is large. Democratic decisions are more beneficial primarily because they tend to produce less extreme decisions, rather than because each individual has an influence on the decision per se. Our model suggests that democracy should be widespread and makes quantitative, testable predictions about group decision-making in non-humans. |
| Address |
School of Biological Sciences, University of Sussex, Brighton BN1 9QG, UK. l.conradt@sussex.ac.uk |
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English |
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Edition |
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0028-0836 |
ISBN |
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| Notes |
PMID:12520299 |
Approved |
no |
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Equine Behaviour @ team @ |
Serial |
5136 |
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| 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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Edition |
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| ISSN |
0028-0836 |
ISBN |
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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 |
de Waal, F.B.M.; Davis, J.M. |
| Title |
Capuchin cognitive ecology: cooperation based on projected returns |
Type |
Journal Article |
| Year |
2003 |
Publication |
Neuropsychologia |
Abbreviated Journal |
Neuropsychologia |
| Volume |
41 |
Issue |
2 |
Pages |
221-228 |
| Keywords |
Animals; Attention; Cebus/*psychology; *Cooperative Behavior; Decision Making; Dominance-Subordination; Female; Male; *Motivation; Reaction Time; Reinforcement Schedule; *Social Behavior |
| Abstract |
Stable cooperation requires that each party's pay-offs exceed those available through individual action. The present experimental study on brown capuchin monkeys (Cebus apella) investigated if decisions about cooperation are (a) guided by the amount of competition expected to follow the cooperation, and (b) made instantaneously or only after a period of familiarization. Pairs of adult monkeys were presented with a mutualistic cooperative task with variable opportunities for resource monopolization (clumped versus dispersed rewards), and partner relationships (kin versus nonkin). After pre-training, each pair of monkeys (N=11) was subjected to six tests, consisting of 15 2 min trials each, with rewards available to both parties. Clumped reward distribution had an immediate negative effect on cooperation: this effect was visible right from the start, and remained visible even if clumped trials alternated with dispersed trials. The drop in cooperation was far more dramatic for nonkin than kin, which was explained by the tendency of dominant nonkin to claim more than half of the rewards under the clumped condition. The immediacy of responses suggests a decision-making process based on predicted outcome of cooperation. Decisions about cooperation thus take into account both the opportunity for and the likelihood of subsequent competition over the spoils. |
| Address |
Living Links, Yerkes Primate Center, Emory University, 954 N. Gatewood Road, Atlanta, GA 30322, USA. dewaal@emory.edu |
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English |
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Edition |
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0028-3932 |
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Conference |
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| Notes |
PMID:12459220 |
Approved |
no |
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refbase @ user @ |
Serial |
182 |
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| Author |
Westerduin, F.E.; Lankveld, D.P.K.; van der Velden, M.A.; Back, W.; Sloet van Oldruitenborgh-Oosterbaan, M.M. |
| Title |
[Splenectomy in a dressage pony: end of sports career?] |
Type |
Journal Article |
| Year |
2003 |
Publication |
Tijdschrift Voor Diergeneeskunde |
Abbreviated Journal |
Tijdschr Diergeneeskd |
| Volume |
128 |
Issue |
13 |
Pages |
406-411 |
| Keywords |
Animals; Biopsy/veterinary; Colic/surgery/veterinary; Horse Diseases/pathology/*surgery/ultrasonography; Horses; Laparotomy/veterinary; Male; Splenectomy/*veterinary; Splenomegaly/surgery/ultrasonography/*veterinary; *Sports |
| Abstract |
A 14-year-old Arabian cross-bred gelding was referred to the University Clinic because of mild, recurrent signs of colic for 5 days. The pony showed icteric mucous membranes, haemolytic blood, and dark coloured urine. Internal examination did not give a clear diagnosis. Unidentified intra-abdominal strands were found and haemorrhagic abdominocentesis led to the decision to perform an exploratory laparatomy. An extremely enlarged spleen was the sole finding. A splenal biopsy sample was taken and surgery was completed. The pony remained colicky, so the spleen was examined by ultrasonography. After this examination, the tentative diagnosis 'tumour of the spleen' was made and splenectomy was performed. Pathological examination of the spleen revealed splenomegaly caused by infarctions of unknown origin. Eight weeks after surgery, the pony started again in dressage competition. Six months after splenectomy, the pony won the provincial dressage competition. |
| Address |
Hoofdafdeling Gezondheidszorg Paard, Faculteit der Diergeneeskunde, Universiteit Utrecht, Yalelaan 12-16, 3584 CM Utrecht. fenna-lambert@planet.nl |
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Dutch |
Summary Language |
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Original Title |
Splenectomie bij een dressuurpony: einde sportcarriere? |
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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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0040-7453 |
ISBN |
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Conference |
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| Notes |
PMID:12870176 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3722 |
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