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Showing papers by "University of Illinois at Urbana–Champaign published in 1986"


Journal ArticleDOI
TL;DR: Two experiments focused upon the following questions: can the spatial extent of the attentional focus be made to vary in response to precues and is there a decrease in processing efficiency for stimuli within the focus?
Abstract: The operation of attention in the visual field has often been compared to a spotlight. We propose that a more apt analogy is that of a zoom or variable-power lens. Two experiments focused upon the following questions: (1) Can the spatial extent of the attentional focus be made to vary in response to precues? (2) As the area of the attentional focus increases, is there a decrease in processing efficiency for stimuli within the focus? (3) Is the boundary of the focus sharply demarked from the residual field, or does it show a gradual dropoff in processing resources? Subjects were required to search eight-letter circular displays for one of two target letters and reaction times were recorded. One to four adjacent display positions were precued by underlines at various stimulus onset asynchronies before display presentation. A response competition paradigm was used, in which the “other target” was used as a noise letter in noncued as well as cued locations. The results were in good agreement with the zoom lens model.

1,782 citations


Journal ArticleDOI
TL;DR: In this paper, a sample of psychologists and anthropologists from all parts of the world was asked to respond to a questionnaire the way they believe an individualist and a collectivist would respond.
Abstract: Individualism and collectivism are terms used by both social scientists and the public, but there are few systematic studies of this dimension. A sample of psychologists and anthropologists from all parts of the world was asked to respond to a questionnaire the way they believe an individualist and a collectivist would respond. The questionnaire described 10 target persons in seven situations. The responses converged, suggesting that there is consensus about the meaning of the dimension. Accordingly, collectivism can be defined as (1) concern by a person about the effects of actions or decisions on others, (2) sharing of material benefits, (3) sharing of nonmaterial resources, (4) willingness of the person to accept the opinions and views of others, (5) concern about self-presentation and loss of face, (6) belief in the correspondence of own outcomes with the outcomes of others, and (7) feeling of involvement in and contribution to the lives of others. Individualists show less concern, sharing, and so on ...

1,409 citations


Journal ArticleDOI
TL;DR: Phenol red has been found to have significant estrogenic activity at the concentrations (15-45 microM) at which it is found in tissue culture media as mentioned in this paper, which has been shown to stimulate the proliferation of estrogen receptor-positive MCF-7 breast cancer cells in a dose-dependent manner.
Abstract: Although much attention has been paid to the removal of hormones from sera and to the development of serum-free media for studies on hormone-responsive cells in culture, little consideration has been given to the possibility that the media components themselves may have hormonal activity. We have found that phenol red, which bears a structural resemblance to some nonsteroidal estrogens and which is used ubiquitously as a pH indicator in tissue culture media, has significant estrogenic activity at the concentrations (15-45 microM) at which it is found in tissue culture media. Phenol red binds to the estrogen receptor of MCF-7 human breast cancer cells with an affinity 0.001% that of estradiol (Kd = 2 X 10(-5) M). It stimulates the proliferation of estrogen receptor-positive MCF-7 breast cancer cells in a dose-dependent manner but has no effect on the growth of estrogen receptor-negative MDA-MB-231 breast cancer cells. At the concentrations present in tissue culture media, phenol red causes partial estrogenic stimulation, increasing cell number to 200% and progesterone receptor content to 300% of that found for cells grown in phenol red-free media, thereby reducing the degree to which exogenous estrogen is able to stimulate responses. The antiestrogens tamoxifen and hydroxytamoxifen inhibit cell proliferation below the control level only when cells are grown in the presence of phenol red; in the absence of phenol red, the antiestrogens do not suppress growth. The estrogenic activity of phenol red should be considered in any studies that utilize estrogen-responsive cells in culture.

1,152 citations



Journal ArticleDOI
TL;DR: Six specific problems with the previously proposed framework for the explanation-based approach to machine learning are outlined and an alternative generalization method to perform explanation- based learning of new concepts is presented.
Abstract: In the last issue of this journal Mitchell, Keller, and Kedar-Cabelli presented a unifying framework for the explanation-based approach to machine learning. While it works well for a number of systems, the framework does not adequately capture certain aspects of the systems under development by the explanation-based learning group at Illinois. The primary inadequacies arise in the treatment of concept operationality, organization of knowledge into schemata, and learning from observation. This paper outlines six specific problems with the previously proposed framework and presents an alternative generalization method to perform explanation-based learning of new concepts.

865 citations


Journal ArticleDOI
TL;DR: It is demonstrated that the amplitude spectrum of this heart rate signal more closely matches that of the input signal to an integral pulse frequency modulation model of the heart's pacemaker than do the spectra of other ECG-derived heart rate signals.
Abstract: We present a simple efficient algorithm for the derivation of a heart rate signal from the electrocardiogram. We demonstrate that the amplitude spectrum of this heart rate signal more closely matches that of the input signal to an integral pulse frequency modulation (IPFM) model of the heart's pacemaker than do the spectra of other ECG-derived heart rate signals. The applicability of this algorithm in cross-spectral analysis between heart rate and other physiologic signals is also discussed.

857 citations


Proceedings Article
11 Aug 1986
TL;DR: The demonstration that by applying the proposed method of cover truncation and analogical matching, called TRUNC, one may drastically decrease the complexity of the knowledge base without affecting its performance accuracy is demonstrated.
Abstract: AQ15 is a multi-purpose inductive learning system that uses logic-based, user-oriented knowledge representation, is able to incrementally learn disjunctive concepts from noisy or overlapping examples, and can perform constructive induction (i.e., can generate new attributes in the process of learning). In an experimental application to three medical domains, the program learned decision rules that performed at the level of accuracy of human experts. A surprising and potentially significant result is the demonstration that by applying the proposed method of cover truncation and analogical matching, called TRUNC, one may drastically decrease the complexity of the knowledge base without affecting its performance accuracy.

839 citations


Journal ArticleDOI
TL;DR: These vectors were utilized to eliminate an efficient transcriptional terminator of T7 RNA polymerase in the cDNA of bovine preproparathyroid hormone by oligonucleotide directed mutagenesis and changed the codon for phenylalanine-19 in the signal peptide to alanine.
Abstract: Chimeric phage-plasmid expression vectors were constructed from pUC18/19 plasmids by cloning a single-stranded DNA (ssDNA) origin of replication from bacteriophage f1 and inserting a bacteriophage T7 promoter within the beta-galactosidase gene. A T7 promoter permits in vivo or in vitro expression of single proteins by the translation of T7 RNA polymerase transcripts. Insertional inactivation of the T7 promoter-containing beta-galactosidase gene permits a simple blue-to-white color cloning assay. Compared with several helper phages that were examined, superinfection with M13K07 resulted in the highest yields of the pTZ plasmids as ssDNA viral particles. These ssDNA promoter plasmids are uniquely suited for protein engineering because they simplify cloning, oligonucleotide directed mutagenesis, verification by enzymatic sequence analysis, and expression of mutant proteins from a single vector. These vectors were utilized to eliminate an efficient transcriptional terminator of T7 RNA polymerase in the cDNA of bovine preproparathyroid hormone by oligonucleotide directed mutagenesis. The mutation changed the codon for phenylalanine-19 in the signal peptide to alanine. In a cell-free system the mutant cDNA transcripts were translated into preproparathyroid hormone, which was converted to proparathyroid hormone in the presence of microsomal membranes.

764 citations


Journal ArticleDOI
TL;DR: Compilers for vector or multiprocessor computers must have certain optimization features to successfully generate parallel code to be able to operate on parallel systems.
Abstract: Compilers for vector or multiprocessor computers must have certain optimization features to successfully generate parallel code.

758 citations


Journal ArticleDOI
TL;DR: It is argued that certain theoretical concepts such as mobility barriers, isolating mechanisms and controllable variables provide much firmer bases for identifying strategic groups within industries and taxonomies for understanding the nature of strategic group formulation can be developed.
Abstract: This paper discusses the concept of strategic groups, focusing upon the importance of intra-industry strategic groupings in understanding differences across firms within an industry. The problems involved in identifying strategic groups within industries are examined through a comprehensive review of recent studies. It is demonstrated that much of the research has used surrogates for elements of a firm's strategic direction, e.g. vertical integration, product range, R & D expenditure, to suggest bases by which creative and sustainable groups are formed. The authors argue that certain theoretical concepts such as mobility barriers, isolating mechanisms and controllable variablesprovide much firmer bases for identifying strategic groups within industries. Thus, taxonomies for understanding the nature of strategic group formulation can be developed. Implications of the strategic group concept for such strategic issues as the structure-performance linkage, firm mobility, patterns of rivalry, industry evolutionand firm growthare then examined. The paper concludes by indicating fruitful directions for strategic group research in the context of the strategic management field.

755 citations


Journal ArticleDOI
TL;DR: A novel type of bacterium has been isolated from various geothermally heated locales on the sea floor with a unique sheath-like structure and monotrichous flagellation that clearly belong to the eubacteria, although no close relationship to any known group could be detected.
Abstract: A novel type of bacterium has been isolated from various geothermally heated locales on the sea floor. The organisms are strictly anaerobic, rod-shaped, fermentative, extremely thermophilic and grow between 55 and 90°C with an optimum of around 80°C. Cells show a unique sheath-like structure and monotrichous flagellation. By 16S rRNA sequencing they clearly belong to the eubacteria, although no close relationship to any known group could be detected. The majority of their lipids appear to be unique in structure among the eubacteria. Isolate MSB8 is described as Thermotoga maritima, representing the new genus Thermotoga.

Journal ArticleDOI
TL;DR: A manufacturing system can be in one of two states: functional and failed, and it moves back and forth between these two states as a continuous time Markov chain, with mean time between failures = 1/ q1, and mean time to repair 1/q2.
Abstract: We address the problem of controlling the production rate of a failure prone manufacturing system so as to minimize the discounted inventory, cost, where certain cost rates are specified for both positive and negative inventories, and there is a constant demand rate for the commodity produced. The underlying theoretical problem is the optimal control of a continuous-time system with jump Markov disturbances, with an infinite horizon discounted cost criterion. We use two complementary approaches. First, proceeding informally, and using a combination of stochastic coupling, linear system arguments, stable and unstable eigenspaces, renewal theory, parametric optimization, etc., we arrive at a conjecture for the optimal policy. Then we address the previously ignored mathematical difficulties associated with differential equations with discontinuous right-hand sides, singularity of the optimal control problem, smoothness, and validity of the dynamic programming equation, etc., to give a rigorous proof of optimality of the conjectured policy. It is hoped that both approaches will find uses in other such problems also. We obtain the complete solution and show that the optimal solution is simply characterized by a certain critical number, which we call the optimal inventory level. If the current inventory level exceeds the optimal, one should not produce at all; if less, one should produce at the maximum rate; while if exactly equal, one should produce exactly enough to meet demand. We also give a simple explicit formula for the optimal inventory level.

Book ChapterDOI
01 Sep 1986
TL;DR: The most popular technique for studying autobiographical memory is a method developed by Sir Francis Galton (1879 a, 1879 b ) in which the subject is presented with a word and asked to find a memory related to that word as discussed by the authors.
Abstract: The purpose of this chapter is ( a ) to describe the forms of autobiographical memory and contrast them with other forms of memory; ( b ) to give a theoretical account of autobiographical memory in terms of the self; (c) to argue for the importance of phenomenal reports in the study of autobiographical memory; ( d ) to examine some of the experimental findings on autobiographical memory in the context of this analysis; ( e ) to give a detailed account of personal memory, one of the important forms of autobiographical memory; and ( f ) to outline a partially reconstructive view of personal memory. The problem The study of autobiographical memory is one of the least well-developed areas in the study of human memory; there is considerable divergence both in what is being investigated and in the terminology used to describe what is being investigated. There is still much work to be done in describing and classifying the basic phenomena in the area. In order to gain an immediate impression of the complexities involved in studying this topic, I want to examine a concrete example. Currently the most popular technique for studying autobiographical memory is a method developed by Sir Francis Galton (1879 a , 1879 b ) in which the subject is presented with a word and asked to find a memory related to that word. This simple task nicely reveals one of the major problems that will be addressed in this chapter – the multiple forms of autobiographical and non-autobiographical memory.

Journal ArticleDOI
TL;DR: A method of lock resolution is given which is appropriate for the non-standard clause form translation, and which has yielded a spectacular reduction in search space and time for one example.

Journal ArticleDOI
TL;DR: In this article, the 1.75-million-year-old faunal assemblage from the FLK Zinjanthropus site at Olduvai Gorge, Tanzania was examined and skeletal-part frequencies were used to evaluate hominid access to and differential transport of carcass portions of differing nutritional value.
Abstract: Human origins research by archaeologists has expanded the evidence of the diet and subsistence activities of ancient hominids. We examine an important component of that evidence, the 1.75-million-year-old faunal assemblage from the FLK Zinjanthropus site at Olduvai Gorge, Tanzania. Skeletal-part frequencies are used to evaluate hominid access to and differential transport of carcass portions of differing nutritional value. Cut-mark frequencies and locations are used to evaluate butchery patterns including skinning, disarticulation, and defleshing of carcasses. In contrast to other recently published assessments of the FLK Zinjanthropus data, we conclude that (1) ancient hominids had full access to meaty carcasses of many small and large animals prior to any substantial loss of meat or marrow bones through other predator or scavenger feeding; (2) ancient hominids were butchering animal carcasses by an efficient and systematic technique that involved skinning, disarticulation, and defleshing; and (3) the FL...

Proceedings ArticleDOI
02 Jul 1986
TL;DR: A new algorithm for floorplan design using the method of simulated annealing to carry out the neighborhood search effectively and achieves a simultaneous minimization of area and total interconnection length in the final solution.
Abstract: We present in this paper a new algorithm for floorplan design using the method of simulated annealing. The major contributions of the paper are: 1. A new representation of floorplans (normalized Polish expressions) which enables us to carry out the neighborhood search effectively. 2. A simultaneous minimization of area and total interconnection length in the final solution. Experimental results indicate that the algorithm performs well in many test problems.

Journal ArticleDOI
TL;DR: The dimension of individualism-collectivism, as identified by Hofstede (1980), was studied using items developed both theoretically and emically in nine diverse cultures in this paper.
Abstract: The dimension of individualism-collectivism, as identified by Hofstede (1980), was studied using items developed both theoretically and emically in nine diverse cultures. The dimension was found to be analysable into four stable etic factors: Individualism had two aspects (Separation from Ingroups and Self-Reliance with Hedonism) and collectivism had two aspects (Family Integrity and Interdependence with Sociability). These four factors are orthogonal to each other. The location of nine cultures on these four factors was used to compute a “collectivism” score which correlated r = + · 73 with Hofstede's (1980) collectivism scores for the nine cultures. This approach enables the measurement of individualism-collectivism in each culture as well as across cultures, and shows that different methods for measuring individualism-collectivism converge.

Journal ArticleDOI
TL;DR: Gentner et al. as discussed by the authors investigated the development of analogy in children and found that children aged 5-7 and 8-10 acted out stories with toy characters and were asked to act out the same stories with new characters.

Journal ArticleDOI
TL;DR: In this paper, the authors present a presentation d'une echelle d'evaluation subjective du soutien social, de SS-A. Les donnees obtenues sur des echantillons universitaires et communautaires ont permis de demontrer sa validite et sa fiabilite.
Abstract: Presentaion d'une echelle d'evaluation subjective du soutien social, de SS-A. Les donnees obtenues sur des echantillons universitaires et communautaires ont permis de demontrer sa validite et sa fiabilite


Journal ArticleDOI
TL;DR: The authors showed that the number of group members that is necessary and sufficient for a collective decision is inversely proportional to the demonstrability of a proposed group response. But they did not consider the problem of group problem solving and decision making.

Book
01 Jan 1986
TL;DR: The authors discuss postpositivism, Objectivity, Relativity, and Value Neutrality in educational inquiry, and can, and should, educational inquiry be scientific, as well as the commitment of postpositionivism to scientific inquiry.
Abstract: Chapter 1 What is Postpositivism? Chapter 2 Philosophical Commitments of Postpositivist Researchers Chapter 3 Objectivity, Relativity, and Value Neutrality Chapter 4 Can, and Should, Educational Inquiry be Scientific?

Journal ArticleDOI
TL;DR: In this paper, the authors compare bribery to competitive bidding in a government purchasing context and show that there is a fundamental isomorphism between bribery and competitive bidding on the supply side of the transaction.


Journal ArticleDOI
TL;DR: Criteria for the classification of juvenile rheumatoid arthritis were analyzed in a detailed database of 250 children in order to assess the accuracy of diagnosis and validity of onset types and course subtypes.
Abstract: Criteria for the classification of juvenile rheumatoid arthritis were analyzed in a detailed database of 250 children in order to assess the accuracy of diagnosis and validity of onset types and course subtypes. A number of conclusions have been derived from this study: All definitions of the 1973 criteria for classification of juvenile rheumatoid arthritis should be retained. The addition of onset types to the 1976 revision of the criteria has been validated. The course of the disease after the onset period of 6 months is as important to the outcome of a group of children as is the onset type. The current classification should be broadened to include the course subtypes.

Journal ArticleDOI
TL;DR: This work studies visibility representations of graphs, which are constructed by mapping vertices to horizontal segments, and edges to vertical segments that intersect only adjacent vertex-segments, and considers three types of visibility representations.
Abstract: We studyvisibility representations of graphs, which are constructed by mapping vertices to horizontal segments, and edges to vertical segments that intersect only adjacent vertex-segments Every graph that admits this representation must be planar We consider three types of visibility representations, and we give complete characterizations of the classes of graphs that admit them Furthermore, we present linear time algorithms for testing the existence of and constructing visibility representations of planar graphs Many applications of our results can be found in VLSI layout

Journal ArticleDOI
TL;DR: The wild parsnip and the Parsnip webworm appear to have reached an evolutionary “stalemate” in the coevolutionary arms race.
Abstract: The parsnip webworm (Depressaria pastinacella) and the wild parsnip (Pastinaca sativa) together represent a potentially "coevolved" system in that throughout their ranges the plant has relatively few other herbivores and the insect has virtually no other hosts. Individual wild parsnip plants within a central Illinois population vary in their content and composition of furanocoumarins, secondary compounds with insecticidal properties. Half-sib and parent-offspring regression estimates of the heritability of furanocoumarins demonstrate that this variation is genetically based. Wild parsnip plants also vary in their resistance to damage by the parsnip webworm, which feeds on flowers and developing seeds. In an experimental garden, seed production in the primary umbel ranged from 0 to 1,664 seeds among individuals, and mean seed production of half-sib families ranged from 3.7 seeds to 446.0 seeds. Approximately 75% of the variation in resistance among half-sib families to D. pastinacella was attributable to four furanocoumarin characteristics-resistance is positively related to the proportion of bergapten and the amount of sphondin in seeds, and negatively related to the amount of bergapten and the proportion of sphondin in leaves. Each of the four resistance factors had significant heritability. Thus, resistance in wild parsnip to the parsnip webworm is to a large extent chemically based and genetically controlled. Genetic correlations among fitness and resistance characters, however, tend to limit coevolutionary responses between herbivore and plant. In greenhouse plants protected from herbivory, several of the resistance factors have negative genetic correlations with potential seed production. Ostensibly, highly resistant plants in the absence of herbivory would be at a competitive disadvantage in the field. The selective impact of the herbivore is also limited in this population by a negative genetic correlation among resistance factors. Selection to increase one resistance factor (e.g., the proportion of bergapten in the seed) would at the same time decrease the amount of a second resistance factor (e.g., the amount of sphondin in the seed). The wild parsnip and the parsnip webworm, then, appear to have reached an evolutionary "stalemate" in the coevolutionary arms race.


Journal ArticleDOI
TL;DR: In this paper, the eutectoid and peritectoid reactions were not observed for near-equiatomic and Ni-rich TiNi alloys, and the precipitation sequence can be written asβ 0 → Ti11Ni14 → Ti2Ni3 → TiNi3.
Abstract: Metallographic studies have been made of precipitation processes in Ti-50 pct Ni and Ti-52 pct Ni (at. pct) shape memory alloys. The eutectoid and peritectoid reactions previously reported for near-equiatomic and Ni-rich TiNi alloys were not observed for either composition. In the Ti-52Ni alloy, diffusional transformations take place, similar to those in supersaturated alloys. The precipitation sequence can be written asβ 0 → Ti11Ni14 → Ti2Ni3 → TiNi3. The solidus line of the TiNi phase in the Ti-52Ni alloy lies at 812 ± 22 °C. Morphological characteristics of the various precipitate phases are described in detail.

Journal ArticleDOI
TL;DR: In this paper, a random vibration method is developed for the response analysis of hysteretic structural systems under stochastic two-dimensional earthquake excitations, where the biaxial restoring force is modelled by coupled nonlinear differential equations; the response statistics are obtained using the equivalent linearization technique.
Abstract: A random vibration method is developed for the response analysis of hysteretic structural systems under stochastic two-dimensional earthquake excitations. The biaxial hysteretic restoring force is modelled by coupled non-linear differential equations; the response statistics are obtained using the equivalent linearization technique. The validity of the proposed model is appraised using available biaxial loading tests of reinforced concrete columns. A parametric study was performed to examine the significance of the effects of biaxial interaction under earthquake excitations. A practical method to evaluate the extreme response statistics is also presented.