8,185 research outputs found

    Intersexual conflict influences female reproductive success in a female-dispersing primate

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    In group-living mammals, individual efforts to maximize reproductive success result in conflicts and compromises between the sexes. Females utilize counterstrategies to minimize the costs of sexual coercion by males, but few studies have examined the effect of such behaviors on female reproductive success. Secondary dispersal by females is rare among group-living mammals, but in western gorillas, it is believed to be a mate choice strategy to minimize infanticide risk and infant mortality. Previous research suggested that females choose males that are good protectors. However, how much female reproductive success varies depending on male competitive ability and whether female secondary dispersal leads to reproductive costs or benefits has not been examined. We used data on 100 females and 229 infants in 36 breeding groups from a 20-year long-term study of wild western lowland gorillas to investigate whether male tenure duration and female transfer rate had an effect on interbirth interval, female birth rates, and offspring mortality. We found that offspring mortality was higher near the end of males’ tenures, even after excluding potential infanticide when those males died, suggesting that females suffer a reproductive cost by being with males nearing the end of their tenures. Females experience a delay in breeding when they dispersed, having a notable effect on birth rates of surviving offspring per female if females transfer multiple times in their lives. This study exemplifies that female counterstrategies to mitigate the effects of male-male competition and sexual coercion may not be sufficient to overcome the negative consequences of male behavior

    Executive function in first-episode schizophrenia

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    BACKGROUND: We tested the hypothesis that schizophrenia is primarily a frontostriatal disorder by examining executive function in first-episode patients. Previous studies have shown either equal decrements in many cognitive domains or specific deficits in memory. Such studies have grouped test results or have used few executive measures, thus, possibly losing information. We, therefore, measured a range of executive ability with tests known to be sensitive to frontal lobe function. METHODS: Thirty first-episode schizophrenic patients and 30 normal volunteers, matched for age and NART IQ, were tested on computerized test of planning, spatial working memory and attentional set shifting from the Cambridge Automated Neuropsychological Test Battery. Computerized and traditional tests of memory were also administered for comparison. RESULTS: Patients were worse on all tests but the profile was non-uniform. A componential analysis indicated that the patients were characterized by a poor ability to think ahead and organize responses but an intact ability to switch attention and inhibit prepotent responses. Patients also demonstrated poor memory, especially for free recall of a story and associate learning of unrelated word pairs. CONCLUSIONS: In contradistinction to previous studies, schizophrenic patients do have profound executive impairments at the beginning of the illness. However, these concern planning and strategy use rather than attentional set shifting, which is generally unimpaired. Previous findings in more chronic patients, of severe attentional set shifting impairment, suggest that executive cognitive deficits are progressive during the course of schizophrenia. The finding of severe mnemonic impairment at first episode suggests that cognitive deficits are not restricted to one cognitive domain

    Experiments in swine feeding. The value of corn and supplementary feeds for pork production.

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    Corn must necessarily be more freely used than any other concentrated feed for pigs in the Corn Belt, because if properly used it is especially well adapted to pig feeding and can usually be marketed in this way to the very best advantage. But it is generally coming to be recognized that so far as health, thrift and rapidity of gains are concerned, corn alone, at least in dry lot feeding, does not give as satisfactory results, especially for growing pigs, as a combination of corn and some feed adding protein to the ration. Wheat shorts is very commonly considered as the best feed to use with corn for young pigs, but other feeds are. upon the market which contain still larger quantities of protein and their merits for pig feeding deserve investigation. If a small reduction in the cost of feeding each- hog in Iowa can be effected by the judicious uses of these feeds, the aggregate for the state will be enormous. Iowa has 7,947,000 hogs, which, with the exception of Illinois with her 4,684,000, is more than twice as many as any other state and about one-sixth the total number in the United States. During the past season Iowa raised more corn than any other state, the crop being about 388,000,000 bushels. With feeds at the usual prices, it is an easy matter by their judicious selection to so supplement com as to add five to fifteen cents per bushel to the profit from feeding corn, thus effecting a reduction of 50 cents to $1.00 on each 100 lbs. gain in weight by the pigs. In the aggregate, if these modest profits are realized they will amount to millions of dollars to Iowa farmers

    The value of corn, oil meal, cottonseed meal, and gluten feed in work horse rations

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    These experiments have not been continued long enough with each feed to suggest infallible conclusions. The work has been carried through two years, however, under excellent conditions for accurate work, and there has been in the fundamental effects of the rations a close similarity of results with the different pairs of horses. While the subject merits more extended study, and future work might give somewhat different results, it seems that the results already obtained justify the following conclusions: 1. The health, spirit, and endurance of work horses were the same when fed corn with a moderate amount of oil meal, or gluten feed, or cottonseed meal; as when fed a corn and oats ration supplying a similar nutritive ratio. 2. The ration of corn and oil meal maintained the weight, flesh, and appearance of the horses fully as well and with less expense than the one of similar nutritive value composed of corn and oats

    Dominance rank but not body size influences female reproductive success in mountain gorillas

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    According to life history theory, natural selection has shaped trade-offs for allocating energy among growth, reproduction and maintenance to maximize individual fitness. In social mammals body size and dominance rank are two key variables believed to influence female reproductive success. However, few studies have examined these variables together, particularly in long-lived species. Previous studies found that female dominance rank correlates with reproductive success in mountain gorillas (Gorilla beringei beringei), which is surprising given they have weak dominance relationships and experience seemingly low levels of feeding competition. It is not currently known whether this relationship is primarily driven by a positive correlation between rank and body size. We used the non-invasive parallel laser method to measure two body size variables (back breadth and body length) of 34 wild adult female mountain gorillas, together with long-term dominance and demography data to investigate the interrelationships among body size, dominance rank and two measures of female reproductive success (inter-birth interval N = 29 and infant mortality N = 64). Using linear mixed models, we found no support for body size to be significantly correlated with dominance rank or female reproductive success. Higher-ranking females had significantly shorter inter-birth intervals than lower-ranking ones, but dominance rank was not significantly correlated with infant mortality. Our results suggest that female dominance rank is primarily determined by factors other than linear body dimensions and that high rank provides benefits even in species with weak dominance relationships and abundant year-round food resources. Future studies should focus on the mechanisms behind heterogeneity in female body size in relation to trade-offs in allocating energy to growth, maintenance and lifetime reproductive success

    Locked and Unlocked Polygonal Chains in 3D

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    In this paper, we study movements of simple polygonal chains in 3D. We say that an open, simple polygonal chain can be straightened if it can be continuously reconfigured to a straight sequence of segments in such a manner that both the length of each link and the simplicity of the chain are maintained throughout the movement. The analogous concept for closed chains is convexification: reconfiguration to a planar convex polygon. Chains that cannot be straightened or convexified are called locked. While there are open chains in 3D that are locked, we show that if an open chain has a simple orthogonal projection onto some plane, it can be straightened. For closed chains, we show that there are unknotted but locked closed chains, and we provide an algorithm for convexifying a planar simple polygon in 3D with a polynomial number of moves.Comment: To appear in Proc. 10th ACM-SIAM Sympos. Discrete Algorithms, Jan. 199

    The Ursinus Weekly, November 25, 1963

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    John F. Kennedy buried at Arlington today: Assassination saddens world • Students react to news of murder • Assassination historically • President\u27s life in review • A statement about John Kennedy • Oswald murdered Sunday • Chapel service held in memory of Kennedy • Editorial: Riderless horse; Reign of reason • Letters to the editor • Students petition for corrective measures at 6th Ave. & Main St. • Candace Sprecher struck by auto • Student editors at Scranton\u27s press conference • Messiah to be presented Dec. 12 • Tara theme of Senior Ball • Donald Barnhouse, TV 10 newscaster to speak • Soviets speak at Phila. Council: UC students question • College group visits Saint Gabriels • Lyndon Baines Johnson sworn in as 36 President Friday November 22, 1963 • Lecture presented on Rome Council • Greek gleanings • Curtain Club\u27s first theatre in round production December 6 • Teacher exams to be given Feb. 15https://digitalcommons.ursinus.edu/weekly/1259/thumbnail.jp

    Cognitive Information Processing

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    Contains reports on four research projects.National Institutes of Health (Grant 1 P01 GM-14940-01)National Institutes of Health (Grant 1 PO1 GM-15006-01)Joint Services Electronics Programs (U.S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E

    Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei)

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    Acoustic signals that reliably indicate body size, which usually determines competitive ability, are of particular interest for understanding how animals assess rivals and choose mates. Whereas body size tends to be negatively associated with formant dispersion in animal vocalizations, non-vocal signals have received little attention. Among the most emblematic sounds in the animal kingdom is the chest beat of gorillas, a non-vocal signal that is thought to be important in intra and inter-sexual competition, yet it is unclear whether it reliably indicates body size. We examined the relationship among body size (back breadth), peak frequency, and three temporal characteristics of the chest beat: duration, number of beats and beat rate from sound recordings of wild adult male mountain gorillas. Using linear mixed models, we found that larger males had significantly lower peak frequencies than smaller ones, but we found no consistent relationship between body size and the temporal characteristics measured. Taken together with earlier findings of positive correlations among male body size, dominance rank and reproductive success, we conclude that the gorilla chest beat is an honest signal of competitive ability. These results emphasize the potential of non-vocal signals to convey important information in mammal communication
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