Showing papers by "University of Missouri published in 1969"

Inferences on the Parameters of the Weibull Distribution

Abstract: The problems of estimation and testing hypotheses regarding the parameters in the Weibull distribution are considered in this paper. The following results are given: 1. Exact confidence intervals for the parameters based upon maximum likelihood estimators are presented. 2. A table of unbiasing factors (depending upon sample size) for the maximum likelihood estimator of the shape parameter is given. 3. Tests of hypotheses regarding the parameters and the power of the test regarding the shape parameter are developed and presented. 4. Sample sizes at which large sample theory may be useful are presented.

Flight Behaviour and Avoidance of Predators in Thomson's Gazelle (Gazella Thomsoni Guenther 1884)

Abstract: [As a suhsidiary result of a study on social behaviour of Thomson's gazelle in Serengeti National Park (Tanzania) there are given informations on flight behaviour and avoidance of predators. Alert posture, flight in galloping and stotting, and especially the relatively soft alarm call are more or less contagious and can release alertness or flight in conspecifics. Shaking of the flank (BROOKS, 1961) does not initiate flight only but galloping in general. It is the last link in a chain of actions which appears completed only in intraspecific situations. In perception of enemies the tommy reacts to optical stimuli from silhouettes and movements. The senses of smell and hearing are not so important in this context. If the tommies have recognized an enemy in time they try to keep it under control (behaviour of fascination). The territorial ♂♂ are especially important in this context. Bachelor herds are found predominantly at the periphery of an area inhabited by a gazelle population. Thus predators often encounter them first. Gaits and behaviour patterns in flight are described with special regard to stotting display. The young fawns stay put (Abliegen, WALTHER, 1059/60) and so are difficult to be seen. The way in which the mother manages her fawn especially during the first days of its life lead to the view that the fawn and the place where it rests are kept from contamination with odors attractive to predators. In rare cases even adult gazelles try to evade predators by lying down. Tommies do not fight against predators when hunted. The mother defends her fawn against jackals and tries to divert hyenas which hunt for her fawn. Factors which influence the flight distance are discussed. The flight distance varies with the different predators according to their danger for gazelles. Experiments showed that adult ♂♂ in herds (bachelors) have a lesser flight distance than ♀♀ in herds, adult ♂♂ have a lower one than subadult ♂ ♂ , territorial ♂♂ have a lower one than adult bachelors, but solitary wandering ♂♂ show the greatest flight distance of all gazelles. Thus age, sex and social status are all significant factors influencing flight distance. By observations of the behaviour in response to predators, human beings, cars and especially by the study of the mistakes in flights from animals which are not predators of gazelles, it was possible to find a few flight releasing factors, most of them similar to or identical with sign stimuli : sudden appearance, direct course (toward the gazelles), size, good perceptibility (contrast), large number of enemies, high speed, proximity, strangeness, and experience. In concrete cases usually several of these factors operate concomitantly. A remarkable number of them are also known as factors which release the following reaction in young ungulates (WALTHER, 1964a, 1966). This may explain certain cases of ambivalent behaviour, especially of gazelle fawns in regard to predators. A few observations on kills of predators lead me to the view that the age, sex and social groups are preyed upon by various predators at different rates. There are relationships between the differences in flight distances, and the spatial distribution according to the social grouping of gazelles on the one hand, and the different hunting methods of the predators on the other hand. The ecological importance of each predatory species depends on its specialization and preference for gazelles as prey animals, its number, and its preferred biotype. Implications for the management of national parks and game cropping outside the protected areas are discussed. Thomson's gazelles show very few behaviour patterns of alertness, alarm, flight and hiding that are restricted to predators only; most patterns are also seen in intraspecific situations. Certain observations lead to the view that these behaviour patterns are adapted primarily to special conditions of the intraspecific realm and work better in it., As a suhsidiary result of a study on social behaviour of Thomson's gazelle in Serengeti National Park (Tanzania) there are given informations on flight behaviour and avoidance of predators. Alert posture, flight in galloping and stotting, and especially the relatively soft alarm call are more or less contagious and can release alertness or flight in conspecifics. Shaking of the flank (BROOKS, 1961) does not initiate flight only but galloping in general. It is the last link in a chain of actions which appears completed only in intraspecific situations. In perception of enemies the tommy reacts to optical stimuli from silhouettes and movements. The senses of smell and hearing are not so important in this context. If the tommies have recognized an enemy in time they try to keep it under control (behaviour of fascination). The territorial ♂♂ are especially important in this context. Bachelor herds are found predominantly at the periphery of an area inhabited by a gazelle population. Thus predators often encounter them first. Gaits and behaviour patterns in flight are described with special regard to stotting display. The young fawns stay put (Abliegen, WALTHER, 1059/60) and so are difficult to be seen. The way in which the mother manages her fawn especially during the first days of its life lead to the view that the fawn and the place where it rests are kept from contamination with odors attractive to predators. In rare cases even adult gazelles try to evade predators by lying down. Tommies do not fight against predators when hunted. The mother defends her fawn against jackals and tries to divert hyenas which hunt for her fawn. Factors which influence the flight distance are discussed. The flight distance varies with the different predators according to their danger for gazelles. Experiments showed that adult ♂♂ in herds (bachelors) have a lesser flight distance than ♀♀ in herds, adult ♂♂ have a lower one than subadult ♂ ♂ , territorial ♂♂ have a lower one than adult bachelors, but solitary wandering ♂♂ show the greatest flight distance of all gazelles. Thus age, sex and social status are all significant factors influencing flight distance. By observations of the behaviour in response to predators, human beings, cars and especially by the study of the mistakes in flights from animals which are not predators of gazelles, it was possible to find a few flight releasing factors, most of them similar to or identical with sign stimuli : sudden appearance, direct course (toward the gazelles), size, good perceptibility (contrast), large number of enemies, high speed, proximity, strangeness, and experience. In concrete cases usually several of these factors operate concomitantly. A remarkable number of them are also known as factors which release the following reaction in young ungulates (WALTHER, 1964a, 1966). This may explain certain cases of ambivalent behaviour, especially of gazelle fawns in regard to predators. A few observations on kills of predators lead me to the view that the age, sex and social groups are preyed upon by various predators at different rates. There are relationships between the differences in flight distances, and the spatial distribution according to the social grouping of gazelles on the one hand, and the different hunting methods of the predators on the other hand. The ecological importance of each predatory species depends on its specialization and preference for gazelles as prey animals, its number, and its preferred biotype. Implications for the management of national parks and game cropping outside the protected areas are discussed. Thomson's gazelles show very few behaviour patterns of alertness, alarm, flight and hiding that are restricted to predators only; most patterns are also seen in intraspecific situations. Certain observations lead to the view that these behaviour patterns are adapted primarily to special conditions of the intraspecific realm and work better in it.]

Minimum Cost Quality Control Tests

Abstract: An expected cost model of a process whose mean is controlled by an X chart is developed. A two-stage numerical procedure is used to calculate the sample size, the number of units produced between samples, and the control limits of optimal control charts. Optimal plans are tabulated for three values of the a priori distribution parameter and three values of each of the three cost coefficients.

Generalized Laws of Refraction and Reflection

Abstract: The generalized laws of refraction and reflection for absorbing media are rederived, avoiding complex angles and using only definitions with measurable parameters. The results are put in a form which, by inspection, reduces to Snell’s and Fresnel’s equations.

Thiamine mutants of the crucifer, Arabidopsis.

Abstract: In higher plants the only obligate organoauxotrophic mutants available are concerned with the synthesis of thiamine, vitamin B1. In Arabidopsis 65 mutants, representing four loci controlling four different steps in the thiamine pathway, have been obtained and identified. Heteroalleles were distinguished within two loci by qualitative and quantitative responses to low and high temperatures. The availability of auxotrophs in higher plants makes it possible to employ highly selective genetic techniques in well-differentiated diploid organisms.

Two Sample Tests in the Weibull Distribution

Abstract: A test based on maximum likelihood estimators is given for testing the equality of the shape parameters in two Weibull distributions with the scale parameters unknown. Tests for the equality of the scale parameters are also presented along with a procedure for selecting the Weibull process with the larger mean life.

Morphologic variation in the cranium and mandible of the white‐tailed deer (Odocoileus virginianus): A comparative study of geographical and four biological distances

Abstract: Several biological distances based on cranial and mandibular variation among breeding groups of white-tailed deer were calculated and compared with geographic distances among the groups. Distances based on epigenetic variation among ten groups were calculated using 16 non-metric variants of the cranium and mandible. Penrose's size and shape distances and Mahalanobis' D2 distance were calculated for 11 groups; the calculations were based on seven skeletal and seven dental metric variables of the mandible. The biological distances were correlated with geographic distance as follows: the epigenetic distance, 0.74; Penrose's shape distance, 0.71; Penrose's size distance, 0.45; and Mahalanobis' distance, 0.37. All correlations were significant at the 0.01 level. The epigenetic and Penrose shape correlations were significantly higher than the Mahalanobis correlation. Because of the conditions under which the breeding groups were selected, it was assumed that genetic affinites among the groups would be a function of geographic distance. The results suggest that the epigenetic distance and Penrose's shape distance reflect genetic affinities among groups better than do the Penrose size and Mahalanobis distances.

Association of Species and Their Relationship to Microtopography Within Old Fields

Abstract: The relationship of vegetational pattern to edaphic environment was examined within the old—field—prairie ecotone of a central Wisconsin drained marsh. Examination of several soil factors established significant correlations between the elevation gradient (with a range of 1.5 m) and organic matter content and moisture. Several species showed definite peaks of frequency and density across the elevation gradient with the invading prairie species predominating on the low ridges and wetland species largely restricted to depressions. Old—field species, such as Poa pratensis and Linaria vulgaris, were present on all topographic positions but appeared to be yielding to competition with the above species groups at the extremes of the elevation gradient. Pattern of species groups was further investigated by the use of normal association analysis. Environmental differences were tested between the resulting subdivisions of this analysis; this further documented the influence of microtopography on the distribution of the vegetation. In addition, organic matter levels were shown to be important in species distribution where differences in elevation were not in control. Normal association analysis and environmental correlation are considered in regard to the continual nature of plant distribution.

The Reproductive Cycle of Daphnia in An Arctic Pool

Abstract: The reproductive cycle of Daphnia middendorffiana living in an arctic pool and an arctic lake is essentially the same An overwintering generation produces one brood of young before shifting to produce broods of embryos which enter diapause The pool warms more rapidly than the lake and has twice the number of day—degrees above 0°C The higher temperature acts only to accelerate the development rate of the Daphnia, and the reproductive shift occurs in mid—July rather than in late August The restriction of population growth to one brood of young in the warmer pool and colder lake is used to illustrate the hypothesis that arctic temperature influences productivity by controlling life cycle rather than by restricting rates of metabolism See full-text article at JSTOR

A Dissonance Approach to Repeat Purchasing Behavior

Abstract: In a laboratory study of consumer choice behavior, decisions tended to be repeated in conformity with a prediction generated from the theory of cognitive dissonance. The results suggest it may be p...

Investigations on the hypothalamo-neurohypophysial neurosecretory system of the grass frog (Rana pipiens) after transection of the proximal neurohypophysis. II. Light- and electron microscopic findings in the disconnected distal neurohypophysis with special emphasis on the pituicytes.

Abstract: With the onset of degeneration of the neurosecretory nerve fibers following transection of the proximal neurohypophysis, the pituicytes phagocytize these nerve fibers. Concomitant with a considerable increase in the size of the pituicytes, which reaches a peak between 8 and 10 days after the transection, the following sequence of events can be observed: reduction of the amount of intergranular axoplasm, increase in the size of some granules, partial or total loss of the electron density of the neurosecretory granules, loss of granule membranes, fusion of some granules, polymorphous axonal content in digestion vacuoles, formation of multilamellate bodies, digestion vacuoles with moderately electron dense peripheral material, empty digestion vacuoles. At about 12 days after the transection many vacuoles appear which subsequently disappear as the pituicytes shrink. Free neurosecretory granules resulting from the disappearance of the axolemma remain intact in the intercellular and perivascular connective tissue spaces and are eventually phagocytized by pituicytes and pericytes. Phagocytosis is considered to be a basic function of pituicytes. The problems related to this function as well as the possible implications for the interpretation of Herring bodies are discussed.

The Illusion of Limited War: Chancellor Bethmann Hollweg's Calculated Risk, July 1914

Abstract: The responsibility for the outbreak of World War I weighed heavily upon Imperial Germany's fifth Chancellor, Theobald von Bethmann Hollweg. “This war torments me,” he confessed to the Liberal Conrad Haussmann during the struggle. “Again and again I ask if it could have been avoided and what I should have done differently.” This soul searching led Bethmann to believe that “all nations are guilty; Germany, too, bears a large part of the blame.” Arguing that “our fate is too colossal to have its origins in singular events,” the Chancellor stressed the larger causes of the conflict. Imperialist rivalry, the anti-German coalition, the growing isolation of Berlin, and Vienna's relative decline, “all that forced us to adopt a policy of utmost risk, a risk that increased with each repetition, in the Moroccan quarrel, in the Bosnian crisis, and then again in the Moroccan question.” But he also admitted candidly: “Lord yes, in a certain sense it was a preventive war,” motivated by “the constant threat of attack, the greater likelihood of its inevitability in the future, and by the military's claim: today war is still possible without defeat, but not in two years! Yes, the generals,” he repeated. “It could only have been avoided by a rapprochement with England, that is still my conviction. But after we had decided for a [common] policy with Austria, we could not desert her in such danger.”