Showing papers by "University of Minnesota published in 1980"
TL;DR: A simple, rapid technique for intrathecal injections by lumbar puncture in unanesthetized mice is described, and submicrogram quantities of morphine sulfate induced Straub tail response and tail-flick analgesia.
1,823 citations
TL;DR: A 30-item questionnaire was devised to measure the frequency of occurrence of automatic negative thoughts (negative self-statements) associated with depression as discussed by the authors, which was cross-validated and found to significantly discriminate psychometrically depressed from nondepressed criterion groups.
Abstract: A 30-item questionnaire was devised to measure the frequency of occurrence of automatic negative thoughts (negative self-statements)associated with depression. Male and female undergraduates were asked to recall dysphoric experiences and to report associated cognitions. One hundred representative cognitions were selected and administered to a second sample, along with the MMPI D scale and the Beck Depression Inventory. Thirty items discriminating between criterion groups of psychometrically depressed and nondepressed subjects were identified. The resultant 30-item automatic thoughts questionnaire (ATQ-30)was cross-validated and found to significantly discriminate psychometrically depressed from nondepressed criterion groups. No differences were found between males and females on the measure. Factor analysis indicated a four-factor solution, with a large first factor reflecting Personal Maladjustment, a second factor indicative of Negative Self-Concept and Negative Expectations, and two lesser factors. The ATQ-30 may provide a means of testing basic theory relating cognitive content to behavioral and affective processes and assessing change in cognitions associated with experimental manipulation or psychotherapeutic intervention.
1,371 citations
TL;DR: A masking model is presented that encompasses contrast detection, discrimination, and masking phenomena that includes a linear spatial frequency filter, a nonlinear transducer, and a process of spatial pooling that acts at low contrasts only.
Abstract: Contrast masking was studied psychophysically. A two-alternative forced-choice procedure was used to measure contrast thresholds for 2.0 cpd sine-wave gratings in the presence of masking sine-wave gratings. Thresholds were measured for 11 masker contrasts spanning three log units, and seven masker frequencies ranging +/- one octave from the signal frequency. Corresponding measurements were made for gratings with horizontal widths of 0.75 degrees (narrow fields) and 6.0 degrees (wide fields). For high contrast maskers at all frequencies, signal thresholds were related to masking contrast by power functions with exponents near 0.6. For a range of low masking contrasts, signal thresholds were reduced by the masker. For the wide fields, high contrast masking tuning functions peaked at the signal frequency, were slightly asymmetric, and had approximately invariant half-maximum frequencies that lie 3/4 octave below and 1 octave above the signal frequency. The corresponding low contrast tuning functions exhibited peak threshold reduction at the signal frequency, with half-minimum frequencies at roughly +/- 0.25 octaves. For the narrow fields, the masking tuning functions were much broader at both low and high masking contrasts. A masking model is presented that encompasses contrast detection, discrimination, and masking phenomena. Central constructs of the model include a linear spatial frequency filter, a nonlinear transducer, and a process of spatial pooling that acts at low contrasts only.
1,241 citations
TL;DR: In this paper, the authors describe methods for conveniently formulating and estimating dynamic linear econometric models under the hypothesis of rational expectations and derive an econometrically convenient formula for the cross-equation rational expectations restrictions.
908 citations
TL;DR: An algorithm for matching images of real world scenes is presented, which quickly converges to good estimates of disparity, which reflect the spatial organization of the scene.
Abstract: An algorithm for matching images of real world scenes is presented The matching is a specification of the geometrical disparity between the images and may be used to partially reconstruct the three-dimensional structure of the scene Sets of candidate matching points are selected independently in each image These points are the locations of small, distinct features which are likely to be detectable in both images An initial network of possible matches between the two sets of candidates is constructed Each possible match specifies a possible disparity of a candidate point in a selected reference image An initial estimate of the probability of each possible disparity is made, based on the similarity of subimages surrounding the points These estimates are iteratively improved by a relaxation labeling technique making use of the local continuity property of disparity that is a consequence of the continuity of real world surfaces The algorithm is effective for binocular parallax, motion parallax, and object motion It quickly converges to good estimates of disparity, which reflect the spatial organization of the scene
891 citations
TL;DR: The conceptual clustering of numerous concepts from family therapy and other social science fields reveals two significant dimensions of family behaviour, cohesion and adaptability as discussed by the authors, i.e., family behavior, cohesion, and adaptivity.
Abstract: The conceptual clustering of numerous concepts from family therapy and other social science fields reveals 2 significant dimensions of family behaviour, cohesion and adaptability. These 2 dimension...
768 citations
TL;DR: Two distinct patterns of context effects are examined, one of which shows a dominance of facilitation for target words in a related context, and the other pattern showsA dominance of interference for target Words in an unrelated context.
Abstract: Using a procedure that isolates the facilitatory and interfering effects of a semantic context, the present study examines two distinct patterns of context effects. One pattern shows a dominance of facilitation for target words in a related context, and the other pattern shows a dominance of interference for target words in an unrelated context. The controlling factor seems to be the overall characteristics of the stimulus list. For materials that include semantic relationships that are consistent in the strength of the relationships, facilitation dominance obtains. For materials that include a wide range of semantic relationship strengths, interference dominance results. These two patterns of facilitation and interference are attributed to two semantic strategies available to subjects for using context information. The explication of the strategies includes a theoretical treatment of the present data.
662 citations
TL;DR: In this paper, the improved canonical variational theory is extended to reactions in a quantum mechanical world where internal energies of reactants are quantized, and a detailed discussion of vibrationally adiabatic models for transmission coefficients for conventional transition state theory and three versions of variational transition-state theory are also presented.
Abstract: The improved canonical variational theory, presented previously for reaction rates in a classical mechanical world, has been extended to reactions in a quantum mechanical world where internal energies of reactants are quantized. A detailed discussion of vibrationally adiabatic models for transmission coefficients for conventional transition-state theory and three versions of variational transition-state theory are also presented. The relationship of the improved canonical variational transition-state theory to the classical limit of these transmission coefficients has been shown. The improved canonical variational theory and the new quantal and classical transmission coefficients are illustrated and tested by applications to quantal collinear and three-dimensional reactions rates for several reactions. Semiclassical approximations to the quantal transmission coefficients are also examined. Applications considered are collinear H + H/sub 2/ and isotopic analogs, Cl + H/sub 2/ and isotopic analogs, and I + H/sub 2/ and three-dimensional D + H/sub 2/, Cl + HD, I + H/sub 2/, I + D/sub 2/, O + H/sub 2/, and F + H/sub 2/.
652 citations
TL;DR: In this paper, two general classes of explanations for such non-Ohmic effects are presented: thermal and electronic. But, as discussed in Section 2.1, the use of the terminology electrothermal encompasses predominantly thermal and predominantly electronic processes as well as all intermediate cases, and therefore should not prejudice the casual observer into concluding that both effects are necessarily important.
Abstract: The application of sufficiently high electric fields to any material eventually results in deviations from linearity in the observed current-voltage I(V) characteristic. There are two general classes of explanations for such non-Ohmic effects— thermal and electronic. Thermal effects arise because the electrons accelerated by the field always emit phonons in an attempt to return to equilibrium. Electronic effects are due to changes in the response of the charged carriers to high applied fields. In general, both effects must be considered in any quantitative analysis, and the two can produce a coupled response ofter called “electrothermal.” The use of the terminology electrothermal encompasses predominantly thermal and predominantly electronic processes as well as all intermediate cases, and therefore should not prejudice the casual observer into concluding that both effects are necessarily important. In a discussion of the physical mechanism in a particular sample, the major parameters controlling its operation must be identified and separated out from the less significant features.
604 citations
TL;DR: A framework for the study of interlanguage strategies of communication, production, and learning is established, and rigorous criteria are proposed to define communication strategies within that framework as discussed by the authors, which is related to research on foreigner talk (Hatch 1979, Hatch, Shapira, and Gough 1978), and repair in interlanguage (Schwartz 1977, Fathman 1980).
Abstract: A framework for the study of interlanguage strategies of communication, production, and learning is established, and rigorous criteria are proposed to define communication strategies within that framework. Research on communication strategies is related to research on foreigner talk (Hatch 1979, Hatch, Shapira, and Gough 1978), and repair in interlanguage (Schwartz 1977, Fathman 1980). The claim is made that much of this research focuses on the same kind of phenomenon in interlanguage communication, but that the conceptual frameworks used by researchers investigating communication strategies, foreigner talk, and repair have in the main been different, and hence caused researchers to “see” different things in the same data.
530 citations
TL;DR: The paper presents a comprehensive framework for research in Management Information Systems MIS, useful not only in understanding and classifying MIS research but also in generating potential hypotheses for future research.
Abstract: The paper presents a comprehensive framework for research in Management Information Systems MIS. The necessity for a more comprehensive research framework is derived from a review of past research frameworks. The new framework is validated by mapping 331 MIS doctoral dissertations into its research categories. The dissertations are also classified by research methodology employed.
The comprehensive MIS research model is useful not only in understanding and classifying MIS research but also in generating potential hypotheses for future research. Hypothesis generation using the model is explained and illustrated.
TL;DR: Neither clinical severity nor erythrocyte adherence correlates significantly with red-cell indexes, hemoglobin concentration, percentage of irreversibly sickled red cells, level of fetal hemoglobin, or reticulocyte count, but these findings are consistent with the hypothesis that abnormal interactions between ery throats and endothelium may be the initiating factor in the development of microvascular occlusions in sickle-cell anemia.
Abstract: We studied 33 patients with sickle-cell anemia to examine the possible relation between the severity of their disease (frequency of microvascular occlusions) and the abnormal adherence of sickle erythrocytes to cultured human endothelium. Neither clinical severity nor erythrocyte adherence correlates significantly with red-cell indexes, hemoglobin concentration, percentage of irreversibly sickled red cells, level of fetal hemoglobin, or reticulocyte count. However, clinical severity and erythrocyte adherence are strongly correlated (rank correlation coefficient = +0.666; P less than 0.001). These findings are consistent with the hypothesis that abnormal interactions between erythrocytes and endothelium may be the initiating factor in the development of microvascular occlusions in sickle-cell anemia.
TL;DR: In this paper, the authors found that aggregation of polymorphonuclear granulocytes (PMN) in response to activated complement (C) might contribute to the genesis of the adult respiratory distress syndrome (ARDS), aggregating PMNs causing pulmonary dysfunction by becoming lodged in the lung as leucoemboli.
TL;DR: Allogeneic bone-marrow transplantation appears to be the treatment of choice in this fatal disorder and vision, hearing, growth, and development were progressively improving 16 months after transplantation.
Abstract: A five-month-old girl with autosomal-recessive osteopetrosis received a bone-marrow transplant from her five-year-old HLA-MLC-identical brother after preparation with cyclophosphamide and modified total-body irradiation. Engraftment was documented by chromosomal analysis. Anemia, thrombocytopenia, and leukoerythroblastosis corrected within 12 weeks of transplantation. Low serum calcium and elevated serum alkaline and acid phosphatase levels became normal. Serial x-ray studies revealed bony remodeling and new nonsclerotic bone formation. A pretransplantation bone biopsy revealed small marrow spaces, rare marrow elements, increased osteoclasts, and no bony resorption. After transplantation, osteoclasts were actively resorbing bone, and medullary cavities contained normal bone marrow. Fluorescent Y-body analysis after transplantation revealed donor (male) osteoclasts and recipient (female) osteoblasts. Monocyte bactericidal activity, markedly decreased before transplantation, became normal. Vision, hearing, growth, and development were progressively improving 16 months after transplantation. Allogeneic bone-marrow transplantation appears to be the treatment of choice in this fatal disorder.
TL;DR: Goat milk contains more potassium and chloride but less orotic acid, N-acetyl neuraminic acid and vitamin B 6, vitamin B 12 than cow milk.
TL;DR: It is concluded that sickle RBC adhere to vascular endothelial cells in vitro, perhaps caused by a calcium-induced aberration of membrane topography, which may be a pathogenetic factor in the microvascular occlusions characteristic of sickle cell disease.
Abstract: The abnormal shape and poor deformability of the sickled erythrocyte (RBC) have generally been held responsible for the microvascular occlusions of sickle cell disease. However, there is no correlation between the clinical severity of this disease and the presence of sickled RBC. In searching for additional factors that might contribute to the pathophysiology of sickle cell disease, we have investigated the possibility that sickle RBC might be less than normally repulsive of the vascular endothelium. After RBC suspensions are allowed to settle onto plates of cultured human endothelial cells, normal RBC are completely removed by as few as six washes. In contrast, sickle RBC remain adherent despite multiple washes. On subconfluent culture plates, normal RBC are distributed randomly, whereas sickle RBC cluster around endothelial cells. Sickle RBC adherence is not enhanced by deoxygenation but does increase with increasing RBC density. The enzymatic removal of membrane sialic acid greatly diminishes the adherence of sickle RBC to endothelial cells, suggesting that sialic acid participates in this abnormal cell-cell interaction. Although net negative charge appears normal, sickle RBC mainfest an abnormal clumping of negative surface charge as demonstrated by localization of cationized ferritin. These abnormalities are reproduced in normal RBC loaded with nonechinocytogenic amounts of calcium. We conclude that sickle RBC adhere to vascular endothelial cells in vitro, perhaps caused by a calcium-induced aberration of membrane topography. This adherence may be a pathogenetic factor in the microvascular occlusions characteristic of sickle cell disease.
TL;DR: In this paper, the Clausius-Duhem inequality for non-Newtonian incompressible fluids of the differential type was introduced, and a set of thermodynamic constraints on the Helmholtz free energy density were established.
Abstract: Today, even though the Clausius-Duhem inequality is widely considered to be of central importance in the subject of continuum thermomechanics, it is also believed to be a somewhat special interpretation of a more fundamental (second) law of thermodynamics. In this work, which is concerned with the relation between thermodynamics and stability for a class of non-Newtonian incompressible fluids of the differential type, we find it essential to introduce the additional thermodynamical restriction that the Helmholtz free energy density be at a minimum value when the fluid is locally at rest. As a background to our main considerations we begin by introducing the general class of Rivlin-Ericksen fluids of complexity n and obtain, for this class, a preliminary set of thermodynamical constitutive restrictions. We then give detailed attention to the special case of fluids of grade 3 and arrive at fundamental inequalities which restrict its (temperature dependent) material moduli. When the moduli are taken to be constant we find that these inequalities require that a body of such a fluid be stable in the sense that its total kinetic energy must tend to zero in time, no matter what its previous mechanical and thermal fields, provided it is both mechanically isolated and immersed in a thermally passive environment at constant temperature from some finite time onward. When the material constants of a fluid of grade 3 are such that the Clausius-Duhem inequality is satisfied but the free energy is not at a minimum in equilibrium, we show that for a broad class of reasonably posed problems the flows are necessarily asymptotically unbounded. Finally, we determine the stability character of non-trivial base flows for fluids of grade 3 with constant material moduli, and establish a uniqueness theorem for the initial-boundary value problem and a uniqueness theorem for problems involving sufficiently slow steady flows.
TL;DR: An empirical comparison of existing algorithms for the computer generation of exact D-optimal experimental designs is carried out and a modification of the Fedorov algorithm is given and shown to effect substantial decreases in the computer time required for design generation.
Abstract: An empirical comparison of existing algorithms for the computer generation of exact D-optimal experimental designs is carried out. Among algorithms considered were those due to Wyrnn, Mitchell, Fedorov, and Van Schalkwyk. A procedure for rounding off approximate designs as suggested by Kiefer is also evaluated. A modification of the Fedorov algorithm is given and shown to effect substantial decreases in the computer time required for design generation.
TL;DR: In this paper, the authors discuss the relationship between polynomials in the indeterminate h, h-l, with coefficients in one of the simple Lie algebras and complete integrability of Hamiltonian systems.
TL;DR: In this article, a general numerical method for convection-diffusion problems is presented, which can be extended to three-dimensional convection diffusion problems and can handle problems in the whole range of Peclet numbers.
Abstract: A general numerical method for convection-diffusion problems is presented The method is formulated for two-dimensional problems, but its key Ideas can be extended to three-dimensional problems The calculation domain is first divided into three-node triangular elements, and then polygonal control volumes are constructed by joining the centroids of the elements to the midpoints of the corresponding sides In each element, the dependent variable is interpolated exponentially in the direction of the element-average velocity vector and linearly in the direction normal to it These interpolation functions respond to an element Peclet number and become linear when it approaches zero The discretization equations are obtained by deriving algebraic approximations to integral conservation equations applied to the polygonal control volumes The proposed method has the conservative property, can handle problems in the whole range of Peclet numbers, and avoids the false-diffusion difficulties that commonly afflict o
TL;DR: The expression of human esterase D was evaluated quantitatively and qualitatively in five persons with partial deletions or duplications of chromosome 13 and showed that the locus of this enzyme is at band 13q14, which should aid in the diagnosis and genetic counseling of retinoblastoma.
Abstract: The expression of human esterase D was evaluated quantitatively and qualitatively in five persons with partial deletions or duplications of chromosome 13. The results showed that the locus of this enzyme is at band 13q14. Deletion of this same band in other subjects has been found previously to indicate a predisposition to the development of retinoblastoma, which was present in the four individuals in this study who had partial deletions of chromosome 13. Because of this close synteny, esterase D evaluation should aid in the diagnosis and genetic counseling of retinoblastoma.
TL;DR: Three experiments are reported which aim to distinguish between mechanisms that might serve joint visual attention between human infants and adults and various explanations of this phenomenon and of the capacity for jointVisual attention.
Abstract: Three experiments are reported which aim to distinguish between mechanisms that might serve joint visual attention between human infants and adults. Between 6 and 18 months of age, the infant will adjust his (or her) line of gaze contingent on a change in the adult's focus of attention but behaves as if the adult is referring to loci within the infants' visual space. Thus, if the adult looks behind the infant, the infant scans the space in front of him. Various explanations of this phenomenon and of the capacity for joint visual attention are discussed.
Journal Article•
TL;DR: The data suggest that continuous long-term heparin infusion is a viable therapeutic alternative in subjects with refractory thromboembolic disease, and a self-recycling, totally implantable infusion pump developed in the laboratory is suggested.
TL;DR: A number of similarities and minor differences between the monoaminergic and peptidergic control of appetite and the central control of analgesia and temperature regulation suggests the possibility that there may be a degree of nonspecificity in the control of these closely related life-sustaining processes.
TL;DR: The chapter discusses the importance of the mechanism of permeation of nucleosides, nucleobases, and nucleotides through the cell membranes of eukaryotes and discusses the carrier model for facilitated diffusion and tests for its applicability to nucleoside and base transport.
Abstract: Publisher Summary This chapter discusses the importance of the mechanism of permeation of nucleosides, nucleobases, and nucleotides through the cell membranes of eukaryotes. Some of the reasons of its importance include (1) many anticancer and immunosuppressive agents presently in use or under development are nucleoside, nucleotide, or nucleobase analogs and a clear understanding of their mode of entry into cells and metabolism is important in the assessment of their mode of action, efficacy, and optimal administration, and (2) radioactively labeled nucleosides and nucleic acid bases are widely used as precursors to label specifically the nucleic acids of various types of organisms or of the viruses or plasmids replicating therein as well as to assess the rates of nucleic acid synthesis. An interpretation of the rates of nucleoside and base incorporation into nucleic acids, be it RNA or DNA, depends on a clear understanding of the extent to which these rates may reflect the rates of the conversion of the extracellular substrate to intracellular nucleotides, which are the direct precursors in nucleic acid synthesis. Elimination of the ambiguities inherent in metabolizing cells is of clear advantage to transport studies. Nucleoside and purine transport have been studied successfully in the absence of intracellular metabolism by the use of erythrocytes or of mutant clones of cultured animal cells that are deficient in specific metabolic enzymes and by the use of cell/substrate systems in which substrate metabolism is blocked in some other manner. The chapter also discusses the carrier model for facilitated diffusion and tests for its applicability to nucleoside and base transport.
TL;DR: In this paper, the Navier-Stokes and energy equations were solved using an elliptic numerical procedure for a horizontal isothermal cylinder, and the flow approach natural convection from a line heat source as Ra → 0 and laminar boundary-layer flow as Ra→ ∞.
TL;DR: In this article, the authors derived refutable predictions from a neoclassical multi-person household model based on competitive assumptions modified to take into account differences in landholding status for male and female agricultural workers from farm and nonfarm households.
Abstract: Few attempts have been made to test empirically the multitude of models formulated to describe household labor supply behavior in the context of rural labor markets in developing countries. In this paper refutable predictions are derived from a neoclassical multi-person household model based on competitive assumptions modified to take into account differences in landholding status. A national sample survey of rural households from India is used to estimate the parameters of the model for male and female agricultural workers from farm and nonfarm households. The estimates generally conform to the implications of the neoclassical-competitive framework.
TL;DR: Exogenous opiates may have a role in the control of stress-related eating, a finding that may have therapeutic implications for humans.
Abstract: The interaction of endogenous opiates and stress-induced eating in rats was evaluated by pharmacological manipulation. Eating induced by the tail-pinch method was inhibited by the opitate antagonist naloxone; after being repeatedly stressed over a 10-day period and then given nalozone, the rats behaved in a manner indistinguishable from the "wet-dog" shakes of opiate withdrawal. Thus endogenous opiates may have a role in the control of stress-related eating, a finding that may have therapeutic implications for humans.
TL;DR: In this article, the mesangium region of the kidney was found to be significantly influenced by changes in the peripheral glomerular capillary as well as by other experimental manipulations.