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Showing papers by "University of Colorado Boulder published in 1980"


Journal ArticleDOI
01 Aug 1980-Energy
TL;DR: In this article, the second law of thermodynamics is used as a basis for evaluating the irreversibility associated with simple heat transfer processes, such as heat augmentation techniques, heat exchanger design, and thermal insulation systems.

612 citations


Journal ArticleDOI
TL;DR: Medium‐sized spiny neurons of the rat neostriatum, identified by intracellular injection of horseradish peroxidase, were examined at both light and electron microscopic levels and were characterized by their heavy investment of dendritic spines.
Abstract: Medium-sized spiny neurons of the rat neostriatum, identified by intracellular injection of horseradish peroxidase, were examined at both light and electron microscopic levels. These neurons were characterized by their heavy investment of dendritic spines, beginning about 20 μm from the soma and continuing to the tips of the dendrites. Their axons arose from the soma or from a large dendritic trunk very near the soma, and tapered rapidly to form a main axonal branch from which arose several smaller initial collaterals. These arborized extensively throughout an area of about the same size as, and highly overlapping with, the dendritic field of the cell, while the main axon could be followed for distances of up to 1 mm in the direction of the globus pallidus. Three major synaptic types were seen in contact with spiny neurons. Boutons containing small round synaptic vesicles formed synapses exclusively with spiny regions of the dendrites, and most of these were axo-spinous. Small, very pleomorphic synaptic vesicles characterized a second bouton type of unknown origin, which made contacts with somata, initial segments, and dendrites, but not dendritic spines. Boutons containing large pleomorphic synaptic vesicles had the most widespread distribution, contacting all regions including dendritic spines. Spines receiving these contacts also were postsynaptic to boutons containing small round vesicles. Axon collaterals of spiny cells formed synapses with large pleomorphic vesicles and made synapses with somata, initial segments of axons, dendrites, and dendritic spines of striatal neurons, including other spiny cells.

545 citations


Journal ArticleDOI
TL;DR: The current state of the theory and its application to low-energy electron-molecule collisions is reviewed in this paper, where the emphasis is on elastic scattering and vibrational and rotational excitation of small diatomic and polyatomic molecules.
Abstract: The current state of the theory and its application to low-energy electron-molecule collisions is reviewed. The emphasis is on elastic scattering and vibrational and rotational excitation of small diatomic and polyatomic molecules. New and traditional theoretical approaches are described, and the results of calculations are compared with existing experimental measurements.

520 citations


Journal ArticleDOI
TL;DR: Three types of antibodies appeared to be highly specific for scleroderma: antibody to Scl-70 antigen, antibody to centromere, and antinucleolar antibody, and the anti-centromere antibody appeared to been highly selective for the CREST variant of progressive systemic sclerosis.
Abstract: Antinuclear antibodies wer demonstrated in the sera of 43 of 45 (96%) patients with progressive systemic sclerosis (22 of 24 with diffuse scleroderma and 21 of 21 with the CREST syndrome variant). This high percentage of positive reactions resulted from the use of a tissue culture substrate (Hep-2) to detect antinuclear antibodies by the indirect immunofluorescent method. Patterns of nuclear staining included diffuse fine speckles, large coarse speckles, nucleolar and centromere staining. When organ sections such as mouse kidney were used as substrate for the detection of antinuclear antibodies, nucleolar staining and centromere staining were the two patterns most frequently overlooked. Three types of antibodies appeared to be highly specific for scleroderma: antibody to Sc1-70 antigen, antibody to centromere, and antinucleolar antibody. The anti-centromere antibody appeared to be highly selective for the CREST variant of progressive systemic sclerosis.

503 citations


Journal ArticleDOI
TL;DR: The hypothesis that selective attention can enhance perceptual sensitivity can be supported, as well as theories of attention, such as “perceptual tuning, ” that suggest very early selective control.
Abstract: The present experiment employed a visual signal-detection task within a cost-benefit (inhibition-facilitation) paradigm to examine the effects of selective attention on perceptual sensitivity. A central cue directed the subjects’ attention to either a right or a left spatial location where a detection task was performed. The cue was either a high/low or neutral-validity indicator of the position in which an event was likely to occur. A rating-scale response scheme in conjunction with the subjects’ target signal locational judgments allowed for the construction of ROC curves for each condition. Significant benefits were found for all subjects, supporting the hypothesis that selective attention can enhance perceptual sensitivity. Deallocation of attention resulted in an inhibition of sensitivity in unattended spatial locations. Subjects were consistently most sensitive in the right spatial location. There were no significant differences in overall response bias among the three conditions or in spatial locations. The results support theories of attention, such as “perceptual tuning, ” that suggest very early selective control.

447 citations


Journal ArticleDOI
TL;DR: Nocodazole has very little effect on interphase metabolism, and following drug release, cells return to a normal cell cycle.

374 citations


Journal ArticleDOI
TL;DR: Several types of facilitation of evoked synaptic responses were investigated in the CA1 region of the in vitro rat hippocampus and were characterized and found to be differentiable processes on the basis of several characteristics.
Abstract: 1. Several types of facilitation of evoked synaptic responses were investigated in the CA1 region of the in vitro rat hippocampus. Homosynaptic paired-pulse facilitation and heterosynaptic frequency facilitation were characterized and found to be differentiable processes on the basis of several characteristics. 2. Paired-pulse facilitation, which occurs when the same input is stimulated twice in rapid succession, is manifested as an increase in both the extracellularly recorded population spike and the field e.p.s.p., and is specific to the set of afferents excited by the first impulse. Responses to other excitatory afferents show no facilitation by a heterosynaptic conditioning pulse. 3. At intervals less than 200 msec, the degree of facilitation produced by a preceding impulse appears to decline as a first order exponential function of time. Facilitation is increased by lowering calcium or raising magnesium concentrations in the bathing medium, with no apparent change in the time constant of the decay process. 4. The phenomenon that has sometimes been termed frequency facilitation, and which occurs during the early phase of repetitive stimulation, appears to be an extension of paired-pulse facilitation. It is seen as an increase in amplitude of both the e.p.s.p. and population spike in response to stimulation of homosynaptic inputs, can be predicted with fair accuracy by assuming that the residual paired-pulse facilitation produced by each impulse adds linearly with that from previous impulses, and is affected by calcium and magnesium ions in the same manner as is paired-pulse facilitation. These two types of facilitation, which apparently share a common mechanism, are termed synaptic or primary facilitation. 5. Another type of facilitation, which we suggest might more properly be called frequency facilitation, develops slowly during the course of repetitive stimulation. It is the result of an increase in cell firing in response to any excitatory input, either homo- or heterosynaptic, at time points at which the field e.p.s.p. is typically depressed. 6. Increases in the potassium concentration of the perfusion medium produce effects similar to those observed with frequency facilitation; stimulation-evoked increases in the extracellular concentration of this ion are hypothesized to underlie this type of generalized facilitation.

346 citations


Journal ArticleDOI
TL;DR: The following drugs seem to cause pancreatitis: azathioprine, thiazides, sulfonamides, furosemide, estrogens, and tetracycline; less convincing, but suggestive evidence exists for: 1-asparaginase, iatrogenic hypercalcemia, chlorthalidine, corticosteroids, ethacrynic acid, phenformin, and procainamide.

335 citations


Journal ArticleDOI
TL;DR: The influence of genetic factors for two personality dimensions was analyzed using data from 12,898 unselected twin pairs of the Swedish Twin Registry and found that about half the phenotypic variation may be attributed to genetic factors.
Abstract: The influence of genetic factors for two personality dimensions was analyzed using data from 12,898 unselected twin pairs of the Swedish Twin Registry. The heritability index was 0.50 (men) and 0.58 (women) for psychosocial instability. Corresponding figures for psychosocial extraversion were 0.54 and 0.66. Thus, about half the phenotypic variation may be attributed to genetic factors.

291 citations


Journal ArticleDOI
TL;DR: The literature on migration has gradually developed along two quite distinct lines as discussed by the authors, from the time of Sjaastads now classic article until the present migration has been taken to represent an investment in human capital over space.
Abstract: From the time of Sjaastads now classic article until the present migration has been taken to represent an investment in human capital over space. If the benefits of movement exceed the costs both appropriately discounted an investment in migration will increase lifetime utility in essentially the same way as will an investment in education. While adopting this very generally acceptable theoretical model the literature on migration has gradually developed along two quite distinct lines. Stemming from sweeping world migrations associated fundamentally with disequilibrium the dominant branch of the economics literature on migration has stressed income and employment opportunity differentials. For example the rural to urban migration observed over long historical periods in most countries is due to higher amenity- corrected levels of expected satisfaction in urban areas. Similarly discoveries of gold former slaves being freed to seek Northern opportunities natural disasters such as dust bowls and so on have led to major and persistent spatial utility differentials with resultant migration. (excerpt)

286 citations


Journal ArticleDOI
TL;DR: The ergonovine maleate test is not benign and may cause severe coronary vasospasm that is unresponsive to sublingual and intravenous nitroglycerin, but may be reversed by intracoronary nitrogoglyin.
Abstract: Recent experience has suggested that the ergonovine maleate test is a safe procedure for the diagnosis of variant angina pectoris, because ergonovine-induced coronary vasospasm has generally been reversible by sublingual nitroglycerin. This report describes five cases of ergonovine-induced coronary vasospasm that were refractory to sublingual nitroglycerin. Four of these patients had cardiac arrest. In two patients the vasospasm was responsive to intracoronary nitroglycerin administration. Three patients died as a result of the test. The two survivors differed from the nonsurvivors in the total dose of ergonovine given (0.1 and 0.15 mg versus 0.17, 0.3 and 0.3 mg, respectively) and in the method of administration of ergonovine. The survivors were given serial doses of 0.05 mg each, whereas the three nonsurvivors received either larger initial doses (0.1 followed by 0.07 mg) or progressive incremental doses (0.05, 0.1 and 0.15 mg serially). Sublingual nitroglycerin, given to all five patients, and intravenous nitroglycerin, given to three of the five, were ineffective in reversing vasospasm. Intracoronary nitroglycerin favorably altered the course of the survivors. Thus, the ergonovine maleate test is not benign and may cause severe coronary vasospasm that is unresponsive to sublingual and intravenous nitroglycerin, but may be reversed by intracoronary nitroglycerin.

Journal ArticleDOI
TL;DR: The purification and characterization of a pectic polymer, rhamnogalacturonan I, present in the primary cell walls of dicots is described and is thought to be composed predominantly of d-galacturonosyl and l-rhamnosyl residues in a ratio of approximately 2:1.
Abstract: The purification and characterization of a pectic polymer, rhamnogalacturonan I, present in the primary cell walls of dicots is described. Rhamnogalacturonan I accounts for approximately 7% of the mass of the walls isolated from suspension-cultured sycamore cells. As purified, rhamnogalacturonan I has a molecular weight of approximately 200,000 and is composed primarily of l-rhamnosyl, d-galacturonosyl, l-arabinosyl, and d-galactosyl residues. The backbone of rhamnogalacturonan I is thought to be composed predominantly of d-galacturonosyl and l-rhamnosyl residues in a ratio of approximately 2:1. About half of the l-rhamnosyl residues are 2-linked and are glycosidically attached to C4 of a d-galacturonosyl residue. The other half of the l-rhamnosyl residues are 2,4-linked and have a d-galacturonosyl residue glycosidically attached at C2. Sidechains averaging 6 residues in length are attached to C4 of the l-rhamnosyl residues. There are many different sidechains, containing variously linked l-arabinosyl, and/or d-galactosyl residues.

Journal ArticleDOI
TL;DR: This article found that more of the environmental influences for parents and offspring and for older siblings operate within families (making family members different from one another) than between families, while the difference between the newer and older data could be due to environmental or genetic changes in the population or to methodological differences.


Journal ArticleDOI
01 Mar 1980-Cell
TL;DR: The results indicate that at least some primary differentiation of embryonic cells is determined by internal factors that segregate in early cleavages, whereas patterns of cleavage are dictated by both internally segregating determinants and external cues.


Journal ArticleDOI
31 Jul 1980-Nature
TL;DR: A convenient technique for visualizing MT polarity based on conditions for tubulin assembly in vitro whereby MT elongation occurs with the associated formation of hooked, protofilament appendages on the MT wall is reported.
Abstract: Microtubules (MTs) are intrinsically polar fibres. Many models for the mechanism of MT-mediated transport and mitosis postulate an important role for MT polarity because a symmetric fibre could not generate force in one direction along its surface. The lack of a convenient method to determine the polar orientation of cellular MTs has hindered experimental testing of these ideas. We report here a convenient technique for visualizing MT polarity based on conditions for tubulin assembly in vitro whereby MT elongation occurs with the associated formation of hooked, protofilament appendages on the MT wall (see Fig. 1). There is polarity information in such junctions between MT walls; our method reveals the polarity of the cellular Mt by the handedness of the hooked appendage as seen in cross-section (Fig. 1).

Journal ArticleDOI
TL;DR: A survey of commercially availabla media revealed that medium F-12 was superior to medium 199 for clonal growth of human epidermal keratinocytes (HK) when supplemented with 10 μg/ml hydrocortisone plus dialyzed fetal bovine serum protein (FBSP), rather than the whole serum used in previous studies.
Abstract: A survey of commercially availabla media revealed that medium F-12 was superior to medium 199 for clonal growth of human epidermal keratinocytes (HK) when supplemented with 10 μg/ml hydrocortisone (HC) plus dialyzed fetal bovine serum protein (FBSP), rather than the whole serum used in previous studies. Qualitative and quantitative adjustment of the medium composition for optimal clonal growth with minimal amounts of FBSP generated a new medium, MCDB 151, which supports clonal growth of HK with 10 μg/ml HC and as little as 1 mg/ml FBSP (equivalent in protein concentration to 2.0% whole serum). MCDB 151 differs significantly from MCDB 105, previously developed in this laboratory for normal human fibroblasts, and each medium selectively favors growth of its own type of cell in primary cultures of disaggregated human neonatal foreskin cells. Differences in the amounts of calcium and adenine in the two media appear to be among the most influential factors mediating the selective growth. Optimal growth of HK occurs at a very low level of Ca2+ that causes the colonies to remain as monolayers rather than stratifying as they do in the presence of higher levels of calcium. However, keratin synthesis, which was examined through use of highly specific fluorescent antibodies, is not affected by the Ca2+ concentration. Agents that increase intracellular cyclic AMP levels appear to have no effect on HK growth in MCDB 151 with 10 μg/ml HC and 1.0 mg/ml FBSP.

Journal ArticleDOI
TL;DR: New values for lipid, water, and caloric contents of eggs of precocial, semiprecocial, semi-altricial, and altricial species are reported to provide an overview of the variation among these values as a function of embryonic maturity at hatching.
Abstract: -The contents of fresh eggs of altricial, semi-altricial, semi-precocial, and precocial birds were compared with values for yolk content gathered from the literature. The continuum of developmental maturity at hatching from altricial to precocial eggs is correlated with an increase in yolk, solids, and caloric contents (per gram wet mass) and a decrease in water content. The proportion of lipid in dry matter and caloric content per gram dry mass does not vary significantly among the four developmental groups. The progressively higher caloric content on a wet mass basis with increasing precocity is a result of a larger solid content and lower water content, rather than variation in caloric value of the dry matter itself. Comparison of values within the same developmental group discloses no significant correlation between relative yolk content and egg mass. The total amount of calories in eggs is more importantly determined by egg mass than by yolk content. A freshly laid avian egg contains the necessary nutrients and raw materials that will eventually produce a hatchling. Although it has been recognized since the study of Tarchanoff (1884) that the initial proportions of yolk and albumen differ considerably in the eggs of altricial and precocial birds, the relations between the energetic and chemical contents of eggs and developmental mode are not completely understood (see Ricklefs 1974, Kendeigh et al. 1977, for review). We report here new values for lipid, water, and caloric contents of eggs of precocial, semiprecocial, semi-altricial, and altricial species. These results are combined with previously published caloric and yolk contents to provide an overview of the variation among these values as a function of embryonic maturity at hatching.

Journal ArticleDOI
TL;DR: It is indicated that the observed similarity of spouses for most variables is due to initial assortment rather than to convergence of phenotypes after initial contact, and that spouses do appear to converge for highly plastic variables such as alcohol consumption and amount of social activity.
Abstract: A very similar pattern of homogamy was found in samples of American and Swedish couples for physical, social, and behavioral variables. In the Swedish sample, there were only minor differences in assortment, i.e., in similarity to spouses, between MZ and DZ twins. Although our data are not conclusive on this point, there was an indication that the observed similarity of spouses for most variables is due to initial assortment rather than to convergence of phenotypes after initial contact. Exceptions are that spouses do appear to converge for highly plastic variables such as alcohol consumption and amount of social activity.

Journal ArticleDOI
TL;DR: In this article, the adsorption and methanation of carbon dioxide on a nickel/silica catalyst were studied using temperature-programmed desorption, and temperatureprogrammed reaction.


Journal ArticleDOI
TL;DR: This article examined the spread of international terrorism from 1968 to 1974 using Poisson and negative binomial probability models and suggested an inverse hierarchy as an explanation for the contagion of violence from Latin America and other third world countries to Western Europe.
Abstract: This study examines the spread of international terrorism from 1968 to 1974. Using Poisson and negative binomial probability models, a diffusion of international terrorism was found in the first segment of the time period (1968–1971) and contagion as a direct modeling process in the second (1973–1974). Accordingly, the theory of hierarchies in which the diplomatic status of a country predicts its degree of imitability was found to operate among Latin American countries during the second portion of the overall period, but not during the first. An inverse hierarchy is suggested as an explanation for the contagion of violence from Latin America and other third world countries to Western Europe. Autocorrelation functions were used to assess which forms of terrorism were most contagious in which regions.

Journal ArticleDOI
TL;DR: Results demonstrate that the heat-induced damage to the photosynthetic apparatus involves not only a functional dissociation of the chlorophyll a/b light-harvesting complex from the photosystem Ii complex, but a physical dissociation as well.


Journal ArticleDOI
TL;DR: The data suggest that opioid peptides depress the inhibitory interneurons and disinhibit the pyramidal cells through the actions of enkephalin and picrotoxin.

Journal ArticleDOI
TL;DR: Flagellar rotation can be driven by a protonmotive force of either sign, and the results imply that the passage of a fixed number of protons carries the flagesllar motor through one revolution.

Journal ArticleDOI
TL;DR: Genetic tests for parental effects were performed on 24 temperature-sensitive embryonic-lethal mutants of the nematode Caenorhabditis elegans, suggesting that some zygotic genes can function early in embryogenesis.

Journal ArticleDOI
TL;DR: In this paper, a polymer supported method for synthesizing deoxypolyn nucleotides was described, and two non-anucleotides were synthesized in a four-hour time.

Journal ArticleDOI
30 May 1980-Science
TL;DR: Genetic types of plasminogen were determined from a donor and a recipient before and after hepatic homotransplantation and demonstrated that the liver is the principal site of synthesis of human plAsminogen.
Abstract: Genetic types of plasminogen were determined from a donor and a recipient before and after hepatic homotransplantation. Examination of the plasminogen types demonstrated that the liver is the principal site of synthesis of human plasminogen.