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Showing papers by "University of Texas at Austin published in 1969"


Journal ArticleDOI
TL;DR: The objective of this paper is to point out how the biological attributes of these flies may have permitted new forms to arise rapidly in the absence of geographical barriers to gene flow.
Abstract: The origin and evolution of species and host racesl in certain phytophagous insect groups have long been a source of disagreement among evolutionary biologists. The rapid establishment of new host races by some stenophagous insects on introduced plants, as well as various other aspects of their biology and distribution, has led several biologists to suggest that new host races and species may arise sympatrically (Brues, 1924; Thorpe, 1930; Smith, 1941; Haldane, 1959; Alexander and Bigelow, 1960; Bush, 1966). Others regard geographic isolation as a prerequisite for speciation in all groups of sexually reproducing animals (for examples see Mayr, 1963). The difficulty in resolving whether either one or the other, or both, modes of speciation may occur in these insects stems directly from the paucity of detailed studies of wild stenophagous insects. Our information on these insects has been derived primarily from studies made over the past hundred years on a few economically important plant pests. One such group that has received particular attention is the Holarctic and Neotropical genus Rhagoletis whose larvae feed within the developing fruits of many plant species such as cherries, blueberries, apples, currants, rose hips, walnuts, and tomatoes. The objective of this paper is to point out how the biological attributes of these flies may have permitted new forms to arise rapidly in the absence of geographical barriers to gene flow.

758 citations


Book ChapterDOI
TL;DR: The theory of cognitive dissonance as mentioned in this paper has been applied to a wide range of psychological phenomena, such as interpersonal relations or feelings toward a communicator and his communication, and it has been used to explain human behavior.
Abstract: Publisher Summary This chapter focuses on theory of cognitive dissonance. The proliferation of research testing and extending dissonance theory results for the most part from the generality and simplicity of the theory. Although it has been applied primarily in social psychological settings, it is not limited to social psychological phenomena such as interpersonal relations or feelings toward a communicator and his communication. Rather, its domain is in the widest of places—the skull of an individual organism. The core notion of the theory is extremely simple: Dissonance is a negative drive state that occurs whenever an individual simultaneously holds two cognitions that are psychologically inconsistent. The very simplicity of the core of the theory is its greatest strength and most serious weakness. Many of the hypotheses that are obvious derivations from the theory are unique to that theory—that is, they could not be derived from any other theory. One of the intriguing aspects of dissonance theory is that it frequently leads to predictions that stand in apparent contradiction to those made by other theoretical approaches, most notably, to a general reward-incentive theory. The implication of the chapter is that dissonant situations are ubiquitous and that man expends a great deal of time and energy attempting to reduce dissonance. It should be obvious that man does many other things as well.

711 citations


Journal ArticleDOI
TL;DR: The model proposes competitive dissipation of absorbed energy by photochemical trapping at reaction centers and by fluorescence and radiationless de-excitation from both the pigment bed and reaction centers of System 2.

668 citations


Book ChapterDOI
TL;DR: This article described research on interpersonal attraction in relation to a philosophy of science in terms of the historical antecedents and current developments, and discussed a possible research paradigm for the study of attitude similarity-dissimilarity and attraction has been discussed.
Abstract: Publisher Summary This chapter describes research on interpersonal attraction in relation to a philosophy of science in terms of the historical antecedents and current developments. The co relational studies of attraction and similarity of attitudes, opinions, beliefs, and values have essentially involved attempts to determine the validity and to extend the generality of this formulation. With minor variations, these studies involved the identification of pairs of individuals who indicate mutual attraction (spouses, fiances, and sociometrically identified friends), an assessment of these individuals on one or more attitudinal measures, and a statistical determination of the pairs' similarity. Often, this similarity is evaluated not only in terms of departure from a theoretical base line of chance pairings but also by comparison with the similarity of random pairs or mutually antagonistic pairs from the same population. The study of attitude similarity between pairs of friends has fed to results parallel to those involving married couples. Misunderstandings and confusions about research goals and research methods in personality and social psychology occur frequently. There are several issues involved when research interest moves from “real-life” studies closely tied to naturalistic observations into laboratory research in which some variables are manipulated and others controlled. A possible research paradigm for the study of attitude similarity–dissimilarity and attraction has been discussed. The chapter also mentions the generality of the similarity–attraction relationship and theory of attraction as reinforcement model.

598 citations


Journal ArticleDOI
TL;DR: This formulation of structure represents the elucidation of the first of the hypothalamic hormones that have been sought for so long and is chemically based on the chromatographic identity in seventeen diversified systems and biologically based on a quantitative comparison of the hormonal activities of the natural and synthetic products.

495 citations


Journal ArticleDOI
11 Oct 1969-Nature
TL;DR: The initial rate of nucleotide sequence variation among rodents is ten-fold higher than that among artiodactyls when divergence time is estimated in years, and this difference diminishes if generations, rather than years, represent the appropriate interval of evolutionary divergence.
Abstract: Nucleotide sequences of rodents and of artiodactyls have been compared by DNA/DNA duplex formation. The rate of evolution in terms of fixation of nucleotide substitutions inferred from non-repeated artiodactyl DNAs is three times greater than that inferred from comparative amino-acid sequence of the α and β chains of haemoglobin from these same organisms. The initial rate of nucleotide sequence variation among rodents is ten-fold higher than that among artiodactyls when divergence time is estimated in years. This difference diminishes if generations, rather than years, represent the appropriate interval of evolutionary divergence.

459 citations


Proceedings ArticleDOI
01 Sep 1969
TL;DR: This is because of many noar paraphrases of the f o l l o w i n g type.
Abstract: struction. This is because of many noar paraphrases of the f o l l o w i n g type. (23) (a) John wants a car. -John warts to heve a car. (b) I suggest an immediate halt ir~ the bombing I suggest that there be an i t r w r ~ d i a t e h a l t in the

318 citations


Journal ArticleDOI
TL;DR: Electrophoretic protein variation is surveyed in six samples representing two subspecies of the house mouse, M. m.
Abstract: A recent survey (Selander and Yang, 1969) of electrophoretically demonstrable genetic variation in proteins in a population of wild house mice (Mus musculus) from Hallowell Farm, Ramona, California, provided a basis for estimating the proportion of polymorphic loci in the total genome. Of 40 loci controlling the 35 enzymes and non-enzymatic proteins studied, 30% were polymorphic, a proportion closely similar to those available for Drosophila pseudoobscura (Lewontin and Hubby, 1966) and for man (Harris et al., 1968; Lewontin, 1967). Because this estimate was based on an analysis of a single population assigned taxonomically to one subspecies (M. m. brevirostris) and derived from ancestral stocks introduced from Europe to North America within historical times (Schwarz and Schwarz, 1943), it seemed desirable to extend the investigation to additional populations and subspecies. In the present paper, we have surveyed electrophoretic protein variation in six samples representing two subspecies of the house mouse, M. m. musculus and M. m. domesticus, occurring in Denmark. Our objectives are to obtain estimates of total genic heterozygosity for comparison with that available for the California population, and to assess the overall degree of genetic difference between the two subspecies, utilizing the loci investigated as a representative sample of the total genome. A genetic comparison of the Danish populations should be of special interest to students of speciation, since M. m. musculus and M. m. domesticus are, in fact, evolutionary semispecies, having acquired many of the attributes of species rank (Mayr, 1963), including conspicuous morphological and behavioral differences. Despite the existence of a zone of allopatric hybridization between the two forms in central Jutland, there appears to be little gene flow between them (Ursin, 1952; and an investigation of protein variation in progress by Hunt). With the Danish material, we have the opportunity to estimate the degree of genetic difference attained by allopatric populations at the critical stage of speciation where coadapted genetic systems are closing and species are forming.

317 citations


Journal ArticleDOI
TL;DR: In two separate experiments as mentioned in this paper, subjects read a standardized description of a crime of negligent automobile homicide and were asked to sentence the defendant to a specific number of years of imprisonment according to their own personal judgment.

275 citations


Journal ArticleDOI
TL;DR: Even though control programs which attempt to reduce coronary heart disease by preventing atherosclerosis may meet some success when applied to middle-aged persons, these programs should be directed toward individuals in the twenties and thirties for maximum benefits.

236 citations



Journal ArticleDOI
TL;DR: An electron-microscopic study was made of nacreous shell growth in several species of marine molluscs as discussed by the authors, showing that the first step in crystal formation is the "polymerization" of part of the pallial fluid to form lamellae parallel to the surface of the epithelium.
Abstract: An electron-microscopic study was made of nacreous shell growth in several species of marine molluscs. Studies of sections of mantle-shell preparations show that the first step in crystal formation is the “polymerization” of part of the pallial fluid to form lamellae parallel to the surface of the epithelium. These lamellae form compartments enclosing a modified apallial fluid. Initiation of crystals occurs in these compartments in contact with a crystal in an adjacent layer. During crystal growth the organic matrix present in the compartment is displaced by the growing surface of the crystal. When growth is complete the crystal is entirely enveloped by a delicate organic sheath. These studies show that the pallial fluid with its organic constituents is responsible for supplying a matrix or substrate for crystal initiation and growth. It serves as a regulatory device for guiding the orderly growth and arrangement of crystals and, further, it may participate in the induction of new crystals. The formation of compartments during shell growth accounts for the uniform thickness, preferred exhibited orientation and mineralogy of the crystals as well as other features exhibited by the mature nacre.


Journal ArticleDOI
01 Apr 1969-Cancer
TL;DR: The skin thickening which is often noted mammographically in association with carcinoma has been shown to be the result of an increase in dermal collagen, whether or not dilatation of dermal lymphatics is also present.
Abstract: The first 38 specimens in a series of carcinomas of the breast studied by correlated mammography and subserial whole organ sectioning are reported. Three specific patterns of tumor growth have been identified and their mammographic appearances described. Intramammary spread of carcinoma has been observed to occur both intraductally and by way of periductal lymphatics. Extensive neoplastic transformation of ductal epithelium and multiplicity of invasive sites have been found frequently. Diffuse or multiple origin has been clearly demonstrated in three fourths of the specimens. The skin thickening which is often noted mammographically in association with carcinoma has been shown to be the result of an increase in dermal collagen, whether or not dilatation of dermal lymphatics is also present. An increase in the collagen of stroma of the breast has also been encountered regularly and is often visible in mammograms. Three specimens containing metastases from previously removed contralateral primaries have permitted observations of the distribution of intramammary lymphatic vessels.

Journal ArticleDOI
TL;DR: In this article, the Dirac equation was solved numerically and the complex scattering amplitudes, which describe the scattering process, were given from the tables it is possible to determine such quantities as the clastic differential cross section, the spin polarization of elastically scattered electrons, the asymmetry of scattered electrons when the incoming electrons are already polarized, and the change of the polarization vector in a scattering experiment Relativistic Hartree-Fock-Slater scattering potentials were used.

Journal ArticleDOI
01 May 1969-Ecology
TL;DR: From data demonstrating habitat specificity, it is concluded that Australian desert lizards recognize more habitats than North American Desert lizards.
Abstract: From data demonstrating habitat specificity, it is concluded that Australian desert lizards recognize more habitats than North American desert lizards. The large amount of environmental heterogeneity and intimate mixing of habitats in Australia allow many more lizard species to coexist there than in North America. An interpretive hypothesis for lizard speciation by means or habitats fluctuating in time and space is proposed. See full-text article at JSTOR

Journal ArticleDOI
TL;DR: In this paper, 40 college students listen to 60 English sentences and attempted to push a button whenever a word in a sentence began with a /b/, and comprehend the sentences. Reaction times (RT) of the button-push responses were recorded.

Journal ArticleDOI
TL;DR: Cycloheximide blocks the movement of peptidyl-tRNA from acceptor (aminoacyl) site to the donor (peptidyl) site on reticulocyte ribosomes and has no effect on the ribosome dependent GTPase activity of TF-II or on the peptide transferase reaction by which peptides on tRNA in the donor ribosomal site are transferred to an amino acid on t RNA in the acceptor site.

Journal ArticleDOI
TL;DR: A parallelism was apparent between the sequential morphologicalDevelopment of the apparatus for the secretion of a polysaccharide product, the fairly direct incorporation of tritiated glucose into the apparatus to become a component of this product and the development of the enzyme reactivity.
Abstract: Cytochemical techniques for the electron microscopic localization of inosine diphosphatase, thiamine pyrophosphatase, and acid phosphatase have been applied to the developing root tip of Zea mays . Following formaldehyde fixation the Golgi apparatus of most of the cells showed reaction specificity for IDPase and TPPase. Following glutaraldehyde fixation marked localization of IDPase reactivity in the Golgi apparatus was limited to the root cap, the epidermis, and the phloem. A parallelism was apparent between the sequential morphological development of the apparatus for the secretion of a polysaccharide product, the fairly direct incorporation of tritiated glucose into the apparatus to become a component of this product and the development of the enzyme reactivity. Acid phosphatase, generally accepted as a lysosomal marker, was found in association with the Golgi apparatus in only a few cell types near the apex of the root. The localization was usually in a single cisterna at the face of the apparatus toward which the production of secretory vesicles builds up and associated regions of what may be smooth endoplasmic reticulum. Since the cell types involved were limited regions of the cap and epidermis and some initial cells, no functional correlates of the reactivity were apparent. Despite the presence of this lysosomal marker, no structures clearly identifiable as ‘lysosomes’ were found and the lack of reaction specificity in the vacuoles did not allow them to be so defined.


Book ChapterDOI
01 Jan 1969
TL;DR: Metaphase chromosome preparations from primary cultures are usually of better quality than those from bone marrow, but in a number of cases bone marrow is the only practical material for cytological preparations; therefore, mastering this technique is essential in studies of mammalian karyotypes.
Abstract: Metaphase chromosome preparations from primary cultures are usually of better quality than those from bone marrow. However, in a number of cases bone marrow is the only practical material for cytological preparations; therefore, mastering this technique is essential in studies of mammalian karyotypes. These reasons include: 1 Not every investigator has a tissue culture laboratory at his disposal. 2 Direct bone marrow preparations reduce the cost. 3 In field trips, bone marrows can be processed with relative ease without large pieces of equipment and supply items, such as fresh growth media. 4 Bone marrow preparations should be made as an insurance in case primary cultures fail or become contaminated. 5 In case of mosaicism, bone marrow offers an excellent second material.

Journal ArticleDOI
TL;DR: The results indicate that the native protein consists of three, possibly identical, subunits, and is required for the synthesis of peptides from aminoacyl transfer RNA.

Journal ArticleDOI
TL;DR: In this paper, the surface properties of noble-gas fccs were investigated in the quasiharmonic approximation of the LJ potential and mean square amplitudes and velocities of vibration were calculated for the (100), (111), and (110) surfaces.
Abstract: Various dynamical surface properties have been calculated for noble-gas crystals in the quasiharmonic approximation. The calculations were carried out for slab-shaped fcc crystals in which the atoms interact through a Lennard-Jones potential. Changes in the force constants near the surface caused by changes in the interplanar spacings (static displacements) have been taken into account. Mean-square amplitudes and mean-square velocities of vibration were calculated for the (100), (111), and (110) surfaces. The surface specific heat, which was calculated for the (100) surface, is found to be positive and to vary as ${T}^{2}$ at low temperatures. So-called dynamic displacements, which are the displacements of the mean atomic positions in a vibrating crystal with free surfaces from the mean positions in the bulk, were calculated for the (100) surface. They are found to increase rapidly with temperature, indicating that thermal expansion is considerably greater at the surface than in the bulk. Some qualitative features of the static displacements for the (100), (111), and (110) surfaces are pointed out and explained. It is shown that the dynamical matrix for a general slab-shaped crystal can be reduced to a real symmetric matrix of the same size; this fact greatly facilitates calculations based on such models. The fact that the mean-square amplitudes diverge at finite temperatures for infinite slab-shaped crystals is discussed; it is found that accurate calculations based on slab-shaped models are possible despite this feature.


Journal ArticleDOI
TL;DR: In this article, a metric of the Kerr-Schild type is derived which contains four arbitrary functions of time, and it is a generalization of Vaidya's shining-star metric, and permits arbitrary acceleration of the source.
Abstract: A metric of the Kerr-Schild type is derived which contains four arbitrary functions of time. It is a generalization of Vaidya's shining-star metric, and permits arbitrary acceleration of the source.

Journal ArticleDOI
TL;DR: A new facultatively autotrophic Thiobacillus has been isolated in pure culture and differs from T. novellus in its ability to grow heterotrophically at faster rates and on a greater range of organic compounds.
Abstract: A new facultatively autotrophic Thiobacillus has been isolated in pure culture. The general physiological characteristics of the organism are described together with a redescription of Thiobacillus novellus. The new isolate differs from T. novellus in its ability to grow heterotrophically at faster rates and on a greater range of organic compounds. It can be transferred readily between autotrophic and heterotrophic conditions. It can grow anaerobically by nitrate respiration on a number of organic compounds, but not on thiosulfate. Some problems in the nomenclature and taxonomy of the thiobacilli are discussed with reference to the new isolate.

Journal ArticleDOI
TL;DR: An algorithm is presented to determine the set of minimal cuts and thus calculate a lower bound to system reliability, intended for digital-computer implementation and computational times are provided.
Abstract: The method most often suggested for determining the reliability of a system is to construct a reliability network, enumerate from the network all mutually exclusive working states of the system, calculate the probability of occurrence of each working state, and sum these probabilities. For a complex system this is not a practical method for there is a very large number of working states. Esary and Proschan suggest a lower bound approximation to reliability that requires the enumeration of a much smaller set of system states. These states are called minimal cuts. An algorithm is presented to determine the set of minimal cuts and thus calculate a lower bound to system reliability. The algorithm is intended for digital-computer implementation and computational times are provided.

Journal ArticleDOI
TL;DR: It is suggested that the blockage of mitosis usually associated with the initiation of cytodifferentiation can be correlated with the formation of cilia and maybe mediated by the transformation of the mitotic centrioles into ciliary basal bodies.

Journal ArticleDOI
TL;DR: In all patients developing angina pectoris, ischemic changes were noted electrocardiographically, suggesting that, initially, ischemia produces a decrease in myocardial compliance and this may also be associated with enhanced sympathetic nervous system activity.
Abstract: In order to determine the associated hemodynamic events, angina pectoris was induced by an atrial pacing technic. In all patients developing angina pectoris, ischemic changes were noted electrocardiographically. The hemodynamic findings were variable: in some patients no changes were noted; in others, significant increases in cardiac output, left ventricular end-diastolic pressures (LVEDP), and femoral arterial and pulmonary arterial pressures occurred. These changes suggest that, initially, ischemia produces a decrease in myocardial compliance and this may also be associated with enhanced sympathetic nervous system activity. Myocardial failure may subsequently ensue, however. The administration of nitroglycerin, during angina at a fixed rapid heart rate, resulted in a reduction in LVEDP and cardiac work. Chest pain was always relieved following these hemodynamic changes, indicating a dependence upon these changes for the effectiveness of nitroglycerin.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the relationship between physical attractiveness and liking in a 2 × 2 factorial design and found that the attractive evaluator who was positive was liked most, while the unattractive evaluators who presented a negative evaluation was liked least.