Showing papers by "University of Nevada, Reno published in 1973"
TL;DR: Large premonitory changes in the extent of S-wave splitting have been observed for two earthquakes in Nevada, and observations of the difference between the two S- wave velocities may provide a simple method for pedicting earthquakes.
Abstract: Application of nonhydrostatic stress to rock induces velocity anisotropy, causing the S wave to split into two components traveling with somewhat different velocities. Large premonitory changes in the extent of S-wave splitting have been observed for two earthquakes in Nevada. Observations of the difference between the two S-wave velocities may provide a simple method for pedicting earthquakes.
60 citations
TL;DR: Competition is purely a physical process, and with few exceptions, such as the crowding up of tuberous plants when grown too closely, an actual struggle between competing plants never occurs.
Abstract: Competition is a word of various meanings. In biology, it originally was introduced to account for the low survival rate of the potential offspring of all creatures. The number of seeds formed by a pea plant may be a dozen; most annual plants produce hundreds or thousands of seeds; cottonwood trees and orchids seeds run to the millions; and, in the case of fern and mushroom spores, there are billions formed by a single individual. Since in a state of equilibrium each plant can be replaced by only a single other one, processes were considered that eliminated the excess offspring (such as the activity of predators). With Darwin's evolution theory, competition took on additional meaning in relation to survival of the fittest. Competition was not anymore a struggle between equals, but a mechanism to award superiority. Competition became a contest, and considerations of combat, struggle, territorial exclusion, and even war entered in the wake of Darwin's ideas. As Warming (1) states, competition is "a consideration of the means by which plants oust each other from habitats." But, it is hard to conceive of any mechanisms by which stationary plants can combat each other to result in an ousting. In an important experimental investigation, Clements, Weaver, and Hanson (2) studied competition. They concluded that "Competition is purely a physical process. With few exceptions, such as the crowding up of tuberous plants when grown too closely, an actual struggle between competing plants never occurs .. .. In the exact sense, two plants, ino matter how close, do not compete with each other as long as the water-content, the nutrient material, the light and heat are in excess of the needs of both. When the immediate supply of a single necessary factor falls below the combined demands of the plants, competitionr begins." When growing sunflower, wheat, and other plants at different distances of each other, Clements et al. (2) found that the closer the plants were spaced to one another, the more they inhibited each other. But, it appeared fromn their data (see Table 1) that: (i) all plants in a competition plot were equally reduced in growth, and (ii) with increasing density of the planting, the production of the plants per unit area tended to reach a maximum value, whichwas not changed, with further decreases in spacing. This is a common experience in all agricultural spacing tests, a result that shows that this form of competition does not provide a mechanism for selection, since all individuals are equally inhibited. The same experience was gained from observations in the field. In the center of Death Valley near the headquarters of the National Monument, with an average yearly rainfall of about
50 citations
TL;DR: Observations indicate that it is not the mere inhibition of DNA synthesis, but some rather more specific event in DNA repair which is responsible for complementary exchanges in somatic crossing over.
Abstract: Glycine max (soybean) is the only known higher plant with a definitely established occurrence of somatic crossing over. This material lends itself to the analysis of somatic crossing over, gross chromosomal aberrations and mutations, all of which may be induced by the same treatment of the mutagen given to seeds. This is made possible because gene Y 11 for chlorophyll development in the variety L65-1237 is incompletely dominant over its allele y 11 , so that twin or double spots composed of a dark green ( Y 11 Y 11 )and a yellow ( Y 11 Y 11 ) component can be observed adjacent to and as mirror images of each other on the light green Y 11 Y 11 leaves in the areas of complementary exchange for these genes. Lack of growth of either component of this double spot as well as several types of chromosomal disturbances give rise to single spots resembling phenotypes of Y 11 Y 11 or Y 11 Y 11 leaves. Point mutations can be studied by looking for green sectors originating from Y 11 Y 11 genotype on the Y 11 Y 11 plants. Seeds obtained from heterozygous plants were treated with caffeine, cytosine arabinoside, actinomycin D and 5-fluoro-deoxyuridine, all known inhibitors of DNA synthesis, and puromycin, an inhibitor of synthesis of proteins. The treatments with caffeine and actinomycin D increased the frequency of somatic crossing over as measured by the frequency of double spots on Y 11 Y 11 leaves, but cytosine arabinoside, 5-fluorodeoxyuridine and puromycin did not. Thus somatic crossing over was induced only by those chemicals which are known to allow rejoining of chromosomes, thereby suggesting a correlation between the two phenomena. These observations indicate that it is not the mere inhibition of DNA synthesis, but some rather more specific event in DNA repair which is responsible for complementary exchanges. Some of these results differ from studies carried out with fungi. The main effect of all chemicals tested, except caffeine and actinomycin D, was inferred to be the production of deletions in Y 11 Y 11 plants which raised the frequency of single (dark green or yellow) spots relative to the doubles. Caffeine was the only chemical which constantly increased the frequency of specific point mutations. In the control material, the great majority of spots are found on the upper surface of the leaf. This picture could not be changed in any of the treated materials, thus indicating uniform resistance of spongy mesophyll tissue to the mutagens applied.
49 citations
TL;DR: The data indicate that NaN(3) is capable of inducing nondisjunction, but does not cause mutations (at this locus), chromosome fragmentations (segmental losses) or somatic crossing over to an appreciable degree.
Abstract: Glycine max (soybean) is one angiosperm which lends itself to the study of somatic crossing over. This is made possible because some varieties have gene combinations Y(11)Y(11), Y(11)y(11) and y(11)y(11) in the segregating populations from Y(11)y(11) plants. The gene in question is responsible for chlorophyll synthesis. The Y(11)Y(11) plants have dark green leaves, Y(11)y(11) are light green and y(11)y(11) plants are golden yellow. The heterozygous plants have dark green, yellow and dark green-yellow (double) spots on the leaves of the untreated control material, whereas the two homozygotes are almost always devoid of somatic sectoring. Application of caffeine, or mitomycin C, to the seeds increased the frequency of double, dark green and yellow spots on the Y(11)y(11) background. Possibly, some dark green or yellow spots originate by failure of one of the two components of what might start as a double spot due to somatic crossing over. The application of NaN(3) increases the frequency of dark green or yellow spots, almost exclusively. The two spots increase in equal frequency. The y(11)y(11) plants so treated do not have any light green sectors, but dark green, Y(11)Y(11), plants do develop a few light green or very dark green spots. The data indicate that NaN(3) is capable of inducing nondisjunction, but does not cause mutations (at this locus), chromosome fragmentations (segmental losses) or somatic crossing over to an appreciable degree. It has previously been shown that caffeine-induced chromosome rejoining in Vicia faba can be inhibited by treating the roots with NaN(3). In the present experiments NaN(3) did not affect the processes of somatic crossing over as induced by caffeine or mitomycin C. The effect was additive. This system offers advantages for studying chemical mutagens in that somatic crossing over, point mutations, segmental losses through chromosome breakage and nondisjunction can all be studied in a single treatment to the seeds.
46 citations
TL;DR: Time out and differential reinforcement were employed to control the disruptive behavior of a 3-year-old boy as mentioned in this paper, and the results showed that behavioral changes were maintained over a 10-month period.
26 citations
TL;DR: Three forms of chorismate mutase (CM1, CM2, CM3) have been found in alfalfa plants and are separable by DEAE-cellulose fractionation and gel electrophoresis.
25 citations
TL;DR: In this paper, the concept of high density compression is applied to a fissionable pellet, consisting of 235U, 233U or 239Pu, and very small critical masses become possible.
Abstract: THE possibility of igniting a thermonuclear micro-explosion by a laser pulse has recently attracted great interest as a result of the proposal to lower the energy requirements by imploding a T-D thermonuclear pellet with a laser pulse of proper shape, thereby increasing its density by a factor of ∼104 over the solid density1. If this concept of high density compression is applied to a fissionable pellet, consisting of 235U, 233U or 239Pu, very small critical masses become possible. These critical masses can be further reduced by surrounding the fissionable pellet with a neutron reflecting material to be compressed, together with the pellet, to high densities. Finally, if this neutron reflecting material consists of thermonuclear material such as T-D, the fission chain reaction rising in the critical pellet will ignite a small thermonuclear explosion in the neutron reflector. The fission chain reaction rises at a much faster rate than for solid densities (such as in atomic bombs) because of the greatly increased densities. The release of thermonuclear neutrons in the reflector will accelerate the fission chain reaction to an even higher speed whereby the heating of the thermonuclear material is accelerated in return, resulting in even more thermonuclear neutrons.
22 citations
TL;DR: A series of 4-substituted pyridine N-oxides (4-ZPyNO) have been found to react with copper(II) acetate to form the dimeric complexes.
22 citations
TL;DR: In this paper, the Sestak-Berggren equation was applied to the dehydration of Mn(HCO2)2· 2H2O as studied by differential scanning calorimetry.
17 citations
TL;DR: In this article, the effect of excess phenylalanine on lipid metabolism of PKU children was investigated, and the effect was shown to be positively associated with the number of seizures.
Abstract: In this study, the effect of excess phenylalanine on lipid metabolism of PKU children was investigated.
16 citations
TL;DR: Animals housed in four environmental conditions-stimulus-enriched, motor-en enriched, stimulus-deprived, and control-were tested for their preference in a choice situation in which they could obtain food pellets by barpressing or from a free dish, indicating that animals in the control and motor- enriched groups barpressed for more food than they took freely.
Abstract: Animals housed in four environmental conditions-stimulus-enriched, motor-enriched, stimulus-deprived, and control-were tested for their preference in a choice situation in which they could obtain food pellets by barpressing or from a free dish. Results indicated that animals in the control and motor-enriched groups barpressed for more food than they took freely, while animals in both the stimulus-enriched and the stimulus-deprived groups preferred to freeload. Explanations of the seemingly paradoxical results are discussed in terms of differences in novelty between the housing environments and the testing situation.
TL;DR: In this paper, a comparison of the WKB evaluation of the quantal approach, P WKB, with the purely classical theory, P C, of vibrational energy transfer is presented.
TL;DR: Preliminary data suggest that nor-isoguaiacin also inhibits energy transfer in rat liver mitochondria, and may also inhibit cytochrome-oxidase.
TL;DR: In this article, a method is presented for the delineation of optimal sampling frequencies in discrete data acquisition programs commonly encountered in the fields of hydrology and water resources, and the implications of information content are investigated in terms of the variability of sample mean and sample variance.
Abstract: A method is presented for the delineation of optimal sampling frequencies in discrete data acquisition programs commonly encountered in the fields of hydrology and water resources. Statistical treatment and the attendant implications of information content are investigated in terms of the variability of sample mean and sample variance. The method is applied to three arbitrarily chosen streamflow gaging stations in the Eel River Basin, California. An examination of the variation of information content with sampling interval has revealed guidelines for the choice of a sampling frequency such that persistence effects and the consequent redundancy of information are minimized.
TL;DR: The frequency of mitomycin C induced somatic crossing over in variety L65-1237 of Glycine max is shown to be dependent upon the (physiological) age of the seed during post germination period and is effective even when no DNA synthesis is going on.
Abstract: The frequency of mitomycin C induced somatic crossing over in variety L65-1237 of Glycine max is shown to be dependent upon the (physiological) age of the seed during post germination period. Effect of mitomycin C during the first four hr of germination is significantly lower than during later periods. This increase in the frequency of somatic crossing over is observed up to about 20–24 hr and is then followed by a decrease. These changes did not appear to be related to the onset and pattern of synthesis of DNA or/and proteins in the embryonic tissues. However, mitomycin C is effective even when no DNA synthesis is going on.
TL;DR: In this article, it was shown that an increase in density will lead to a decrease in the required laser energy, whereby the reduction in required energy input is inversely proportional to the square of the achieved density.
Abstract: 1 . I t has been shown (1.2) that very high densities can be possibly achieved by the laser induced implosion of a spherical mass. The purpose for this proposed implosion technique was to achieve high densities in laser produced thermonuclear plasmas. The same implosioll technique in principle should b~ also possible with relativistic electron beams which have been previously proposed (3) as an alternative to laser beams for the controlled release of thermonuclear energy by mieroexplosions. Rather detailed calculations predict for this implosion method pressures up to ~ l0 TM dyn/cnd. If hydrogen at low temperatures with a Fermi electron distribution is subjected to this pressure its density will rise to a value ~104 times larger than its solid-state density. The importance of this is that an increase in density will lead to a decrease in the required laser energy, whereby the reduction in the required energy input is inversely proportional to the square of the achieved density.
TL;DR: In this article, two concentric conductors of toroidal symmetry are placed within a toroidal magnetic field coil producing a magnetic field directed along the circular toroidal ring axis and varying in time.
Abstract: THE principle of my idea can be explained by Fig. 1, which shows a cross section through the proposed machine. The machine has two concentric conductors of toroidal symmetry which are placed within a toroidal magnetic field coil producing a magnetic field directed along the circular toroidal ring axis and varying in time. The space inside the inner conductor and in between the inner and outer conductor is a hard vacuum. The inner conductor is assumed to have a minor radius of ri and the outer conductor a minor radius of ra.
TL;DR: It is suggested that deoxyribose cytidine (d-C) predisposes the chromatin to breakage by AM, perhaps, by increasing the number of accessible chromatin sites by attacking chromatin-nuclear membrane associations.
Abstract: When human leukocytes cultured in vitro are treated with the antileukemic antibiotic adriamycin (AM), several kinds of chromosome aberrations including fragments, and reunions of chromatid as well as chromosome type are observed. The frequency of all these types of aberrations is increased if cells are treated just before, or simultaneously with deoxyribose cytidine. The increase in the incidence of free fragments is not at the expense of exchanges, thus indicating that synergistic effect is real and is due to some mechanism which facilitates the action of AM on chromosomes. It is suggested that deoxyribose cytidine (d-C) predisposes the chromatin to breakage by AM, perhaps, by increasing the number of accessible chromatin sites by attacking chromatin-nuclear membrane associations.
TL;DR: Eustrongylides wenrichi, in its encystment in the musculature, viscera, and egg-mass, was found to be highly pathogenic to bullfrogs.
Abstract: In a survey of tbe helminth parasites of bullfrogs in the area of Ash Meadows, Nevada, 12 species comprising 7 genera were collected. The helminths recovered are as follows: (Nematoda) Eustrongylides wenrichi , Spironoura calesbianae and Abbreviata sp.; (Trematoda) Langeronia provitellaria , Glypthelmins quieta , G. subtropica , G. proximus , G. sera , Haematoloechus buttensis , H, breviplexus , and H. parviplexus ; (Cestoda) Ophiotaenia magna . Brief discussions on each of the preceding parasites are presented. Eustrongylides wenrichi , in its encystment in the musculature, viscera, and egg-mass, was found to be highly pathogenic to bullfrogs.
TL;DR: In this paper, a convergence theorem for a method of solving Fredholm integral equations due to Kalabaet et al. was established for the method of computing the resolvent kernel.
Abstract: A convergence theorem is established for a method of solving Fredholm integral equations due to Kalabaet al. To do this, an interpolation procedure is developed for obtaining an approximation of the resolvent kernel. The results of Anselone and Moore on collectively compact operators are then applied to show convergence.
TL;DR: Negative exponential functions have been used to describe the size distribution of cattle ranches as discussed by the authors, and these functions were found to be sufficiently stable over time to be used in projecting future size distributions of firms.
Abstract: Negative exponential functions adequately describe the size distribution of western cattle ranches. Further, these functions were found to be sufficiently stable over time to be used in projecting future size distributions of firms. As such, these exponential functions provide an attractive alternative to Markov type projections.
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TL;DR: In this paper, the problem of vibrationally and rotationally inelastic scattering processes in H 2 + Ar for nonzero impact parameter b has been investigated in the collision velocity range of 10 6 −10 7 cm/sec by use of the sudden approximation.
TL;DR: An alternative to current analyses of suicidal behavior is discussed: suicidal acts should be assessed within a broader framework of coping styles and stress situations occurring over a period of time.
Abstract: Sn?nmary.-An alrernative to current analyses of suicidal behavior is discussed: suicidal acts shocld be assessed within a broader framework of coping styles and stress situations occurring over a period of time. One of the major implications for research is that suicidal acts will not be seen as unique, isolated events but instead can be understood within the larger context of related psychological knowledge. Suicide has been the focus of many investigations in recent years, and an extensive literature has accumulated concerning its incidence and nature. Studies to date have resulted in an increased awareness of the marked complexity of suicidal behavior and of the difficulty of analyzing the many factors in suicide research; these studies, however, have clearly failed to provide an adequate over-all picture of the suicide phenomenon. One noticeable gap in our understanding concerns adaptive processes leading up to the suicidal act, particularly from the perspective of the individual who is attempting to cope with the psychological stress and pressures which precede a suicidal attempt. Thus, there have been no systematic empirical efforts to analyze the ways in which persons who attempt suicide typically cope with stress situations in their lives. Most of the investigations to date have concentrated either on demographic analyses (Bruhn, 1962; Dublin, 1963; MacMahon, Johnson, & Pugh, 1963; Tuckman & Youngman, 1963; Farberow, Shneidman, & Neuringer, 1966), sociological aspects (Stengel, 1964; Tuckman, Youngman, & Kriezman, 1964; Quimey, 1965; Maris, 1967; Kahne, 1968; Blachly, 1969; Lester, 1970), psychometric evaluations of the inuapersonal dynamics of the suicidal person (Simon & Gilberstadt, 1958; Applebaum & Holzman, 1962; Sapolsky, 1963; Neuringer, McEvoy, & Schlesinger, 1965; Devries, 1966; Farberow & McEvoy, 1966), or the effects and consequences of the suicidal act itself (Litman, Curphey, Shneidman, Farberow, & Tabachnick, 1963; Kacon, 1964; Cain, Fast, & Erickson, 1964; Litman, 1965; Margolis, Meyer, & Louw, 1965; Tuckman & Ziegler, 1966). Some theoretical discussions, however, have emphasized how suicidal tendencies of individuals can be understood by analysis of their lifelong patterns of living (Shneidrnan, 1966; Murray, 1967; Alvarez, 1972). How an individual deals with stress is of particular interest. The emphasis is on dynamic personalicy trait patterns such as attitudes, beliefs, and needs, however, rather than on situational determinants. In the proposed approach of investigation, the nature of the specific stress situation is as important as the coping patterns developed by an individual.
TL;DR: In this article, the authors present Brandes's interpretation of Douglass's original article, which conflicts with that which Douglass offers in his reply, and with the dominant impression that agriculture dominates the local economy of both villages and that even the nucleus presents an agrarian aspect.
Abstract: which is the most favored agriculturally is that which is undergoing rapid farm abandonment, whereas the village (Murelaga) which is least favored agriculturally manifests marked demographic stability in the rural section of the population" (Ibid.: 1111). The term "favored" more than implies relative economic advantage. When we are in addition told that agriculture dominates the local economy of both villages and that "in both villages even the nucleus presents an agrarian aspect" (Ibid.: 1103), the dominant impression we receive certainly coincides with Brandes's interpretation (1973) of the original article, and conflicts with that which Douglass offers in his reply.
TL;DR: As judged by results of gel electrophoresis and effector sensitivity, the number of chorismate mutase isozymes differs in extracts of the three fungi investigated.