| Home | << 1 2 3 4 5 6 7 8 9 10 >> [11–14] |
|
Gatta, D., Baragli, P., Ferrarini, N., Ciattini, F., Sighieri, C., & Colombani, B. (1998). Fitness evaluation in endurance horses by standardised exercise test on treadmill. Valutazione dello stato di allenamento del cavallo da endurance mediante test standardizzato su trea, 9(4), 57–69.
Abstract: Endurance horses, like marathon runners, undertake sub-maximal, longterm physical exercises and in both cases thermoregulation plays a critical role. A standardised sub-maximal treadmill test was used to assess fitness and training state in endurance horses. Literature reports that trained human athletes dissipate head load better than not trained ones; in this study parameters related to thermoregulation were recorded together with other haematologic and metabolic ones. Six endurance horses, divided into two groups according to their training state, performed two submaximal tests at a distance of one week. Blood samples were collected at rest, during exercise, at the end and during recovery (10, 30 and 60 minutes after work). Heart rate (HR), respiratory rate (RR), rectal (RT) and skin (ST) temperatures were monitored through the exercise (and recovery for HR). HR resulted significantly lower (P<0.01) in trained horses than in untrained ones, especially during recovery. Also rectal and skin temperatures resulted significantly lower (P<0.05) in trained horses and ST increased more gradually during exercise. The values of haematocrit and haemoglobin resulted significantly lower (P<0.05) at rest, during exercise and recovery samples. In this study, the parameters related to thermoregulation, in accordance with data from human athletes, resulted significantly different in trained and untrained horses, while other parameters didn't vary significantly between the two groups. Thermoregulatory responses to exercise-generated heat load in a standardised test, studied by simple parameters, can thus offer useful information about fitness and training state of endurance horses.
|
|
Shettleworth, S. J. (1998). Cognition, Evolution and Behaviour. Oxford: Oxford University Press.
Abstract: Description
How do animals perceive the world, learn, remember, search for food or mates, and find their way around? Do any non-human animals count, imitate one another, use a language, or think as we do? What use is cognition in nature and how might it have evolved? Historically, research on such questions has been fragmented between psychology, where the emphasis has been on theoretical models and lab experiments, and biology, where studies focus on evolution and the adaptive use of perception, learning, and decision-making in the field. Cognition, Evolution and the Study of Behavior integrates research from psychology, behavioral ecology, and ethology in a wide-ranging synthesis of theory and research about animal cognition in the broadest sense, from species-specific adaptations in fish to cognitive mapping in rats and honeybees to theories of mind for chimpanzees. As a major contribution to the emerging discipline of comparative cognition, the book is an invaluable resource for all students and researchers in psychology, zoology, behavioral neuroscience. It will also interest general readers curious about the details of how and why animals--including humans--process, retain, and use information as they do. Reviews “This book is a very comprehensive review of animal cognition. It differs from other texts on this topic in a number of ways, as outlined by Shettleworth in her preface and in the opening chapter. Essentially, Shettleworth wants to advocate an 'adaptationist or ecological approach to cognition'. In doing so, she brings together a wealth of data on animal cognition, studied from quite different theoretical viewpoints, such as cognitive ethology, animal learning theory, neuroscience, behavioural ecology and cognitive psychology. . . . Each chapter ends with a clear and useful summary, and helpful suggestions for further reading. The book's numerous illustrations, which are mostly tables or figures redrawn by Margaret Nelson, greatly add to its appeal. . . . [T]his is a marvellously rich, well-written and stimulating book. . . . I greatly enjoyed reading [and] recommend it highly to anyone interested in animal cognition, evolution and behaviour.”--Animal Behaviour “Sara Shettleworth has probably written the most comprehensive study of the animal mind ever and therefore a fundamental textbook on 'comparative cognition'. She first gets consciousness out of the way: whether an animal is conscious or not is impossible to determine, since consciousness is a private, subjective phenomenon. We can study cognition, and certainly cognition lends credibility to the idea that at least some animals must be at least to some degree conscious, but experiments can only prove facts about cognition. She reviews the field of cognitive ethology from the beginning and then analyzes the main cognitive tasks from an information-processing perspective By the end of her review of cognitive faculties, it become apparent that, at least among vertebrates, there are no significant differences in learning, except for language. All vertebrates are capable of 'associative' learning What no other vertebrate seems to be capable of is 'syntax'.” -- Piero Scaruffi, Thymos.com |
|
Dunbar, R. I. M., & Bever, J. (1998). Neocortex size predicts group size in carnivores and some insectivores. Ethology, 108(8), 695–708.
Abstract: Neocortex size has been shown to correlate with group size in primates. Data for carnivores and insectivores are used to test the generality of this relationship. The data suggest that carnivores lie on the same grade as the primates, but that insectivores lie on a separate grade to the left of these two orders. Among the insectivores, there appears to be a distinction between the 'advanced' genera (which show a relationship between group size and neocortex size) and the 'basal' genera (which do not).
|
|
Clayton, N. S., & Dickinson, A. (1998). Episodic-like memory during cache recovery by scrub jays. Nature, 395(6699), 272–274.
Abstract: The recollection of past experiences allows us to recall what a particular event was, and where and when it occurred1,2, a form of memory that is thought to be unique to humans3. It is known, however, that food-storing birds remember the spatial location4, 5, 6 and contents6, 7, 8, 9 of their caches. Furthermore, food-storing animals adapt their caching and recovery strategies to the perishability of food stores10, 11, 12, 13, which suggests that they are sensitive to temporal factors. Here we show that scrub jays (Aphelocoma coerulescens) remember 'when' food items are stored by allowing them to recover perishable 'wax worms' (wax-moth larvae) and non-perishable peanuts which they had previously cached in visuospatially distinct sites. Jays searched preferentially for fresh wax worms, their favoured food, when allowed to recover them shortly after caching. However, they rapidly learned to avoid searching for worms after a longer interval during which the worms had decayed. The recovery preference of jays demonstrates memory of where and when particular food items were cached, thereby fulfilling the behavioural criteria for episodic-like memory in non-human animals.
|
|
Connor, R. C., Mann, J., Tyack, P. L., & Whitehead, H. (1998). Social evolution in toothed whales. Trends. Ecol. Evol, 13(6), 228–232.
Abstract: Two contrasting results emerge from comparisons of the social systems of several odontocetes with terrestrial mammals. Researchers have identified remarkable convergence in prominent features of the social systems of odontocetes such as the sperm whale and bottlenose dolphin with a few well-known terrestrial mammals such as the elephant and chimpanzee. In contrast, studies on killer whales and Baird's beaked whale reveal novel social solutions to aquatic living. The combination of convergent and novel features in odontocete social systems promise a more general understanding of the ecological determinants of social systems in both terrestrial and aquatic habitats, as well as the relationship between relative brain size and social evolution.
|
|
Yulk G. (1998). Leadership in organizations. Englewood Cliffs, NJ: Prentice-Hall.
Abstract: Yulk G. 1998. Leadership in organizations. Englewood Cliffs, NJ: Prentice-Hall
Leadership in Organizations focuses on effective leadership in organizations through both theory and practice. This book explains and critiques the major theories and studies that are most relevant and informative and reviews what we know about leadership effectiveness. This combination of theory and practice makes this text a useful resource for practicing managers who are looking for something more than superficial answers to difficult questions about leadership. |
|
Kronfeld, D. S., Custalow, S. E., Ferrante, P. L., Taylor, L. E., Wilson, J. A., & Tiegs, W. (1998). Acid-base responses of fat-adapted horses: relevance to hard work in the heat. Appl. Anim. Behav. Sci., 59(1-3), 61–72.
Abstract: Feeding and training may affect acid-base responses to strenuous exercise. Acidosis usually correlates with higher blood lactate concentrations during intense exercise, but alkalosis has been found in several studies of horses, and higher lactate responses during sprints have been found in fat adapted horses. To elucidate these unexpected findings, we applied a comprehensive physicochemical approach to evaluate acid-base responses during exercise in fat adapted horses. In incremental tests and repeated sprints, changes in blood [H+] were dependent upon corresponding changes in pCO2 but not strong ion difference (SID, the algebraic sum of ions of sodium, potassium, chloride and lactate). The influence of changes in [Lac-] were largely offset by changes in [Na+], [K+] and [Cl-], so that SID was unchanged and did not contribute to the exercise induced acidemia, so it may be inaccurate to term this a lacticacidosis. During repeated sprints, central venous [H+] increased (acidosis) but arterial [H+] decreased (alkalosis). These changes were consistent with concurrent changes in venous and arterial pCO2 but not SID. Fat adaptation decreased mixed venous pCO2 during repeated sprints, which is consistent with the lower respiratory quotient associated with fat oxidation. Less pulmonary work to eliminate CO2 could benefit horses under hot and humid conditions, especially those with mildly reduced pulmonary function. The blood lactate response was decreased during aerobic tests but increased during anaerobic tests on fat adapted horses. Fat adaptation appears to facilitate the metabolic regulation of glycolysis, by sparing glucose and glycogen at work of low intensity, but by promoting glycolysis when power is needed for high intensity exercise. The blood lactate response to repeated sprints was increased more by the combination of fat adaptation and oral supplementation of sodium bicarbonate than by the sum of the responses to fat alone or bicarbonate alone. This synergism suggests that need for further studies of the interaction of fat adaptation with dietary cation-anion balance, especially under hot conditions. These results integrate harmoniously with previous findings of lower feed intake and fecal output, lower loads of heat and CO2, lower water losses in the feces and by evaporation, and less spontaneous activity and reactivity in fat adapted horses. Thus fat adaptation confers several advantages on horses and presumably other equids used for hard work, especially in the heat.
Keywords: Acid-base; Strong ion difference; pCO2; Exercise; Fat adaptation; Corn oil; Ambient heat; Horse
|
|
Watts, D. J., & Strogatz, S. H. (1998). Collective dynamics of /`small-world/' networks. Nature, 393(6684), 440–442.
Abstract: Networks of coupled dynamical systems have been used to model biological oscillators Josephson junction arrays excitable media, neural networks spatial games11, genetic control networks12 and many other self-organizing systems. Ordinarily, the connection topology is assumed to be either completely regular or completely random. But many biological, technological and social networks lie somewhere between these two extremes. Here we explore simple models of networks that can be tuned through this middle ground: regular networks 'rewired' to introduce increasing amounts of disorder. We find that these systems can be highly clustered, like regular lattices, yet have small characteristic path lengths, like random graphs. We call them 'small-world' networks, by analogy with the small-world phenomenon (popularly known as six degrees of separation). The neural network of the worm Caenorhabditis elegans, the power grid of the western United States, and the collaboration graph of film actors are shown to be small-world networks. Models of dynamical systems with small-world coupling display enhanced signal-propagation speed, computational power, and synchronizability. In particular, infectious diseases spread more easily in small-world networks than in regular lattices.
|
|
Gosling, S. D. (1998). Personality dimensions in spotted hyenas (Crocuta crocuta). J Comp Psychol, 112(2), 107–118.
Abstract: Personality ratings of 34 spotted hyenas (Crocuta crocuta) were made by 4 observers who knew the animals well. Analyses suggest that (a) hyena personality traits were rated with generally high reliability; (b) 5 broad dimensions (Assertiveness, Excitability, Human-Directed Agreeableness, Sociability, and Curiosity) captured about 75% of the total variance; (c) this dimensional structure could not be explained in terms of dominance status, sex, age, or appearance; and (d) as expected, female hyenas were more assertive than male hyenas. Comparisons with previous research provide evidence for the cross-species generality of Excitability, Sociability, and especially Assertiveness. Discussion focuses on methodological issues in research on animal personality and on the potential contributions this research can make for understanding the biological and environmental bases of personality.
|
|
Oakenfull, E. A., & Ryder, O. A. (1998). Mitochondrial control region and 12S rRNA variation in Przewalski's horse (Equus przewalskii). Anim Genet, 29(6), 456–459.
Abstract: Variation in the control region and the 12S rRNA gene of all surviving mitochondrial lineages of Przewalski's horse was investigated. Variation is low despite the present day population being descended from 13 individuals probably representing animals from three different regions of its range. Phylogenetic comparison of these sequences, with sequences for the domestic horse, does not resolve the ancestral status of either horse.
|