Showing papers by "University of Pennsylvania published in 1978"
TL;DR: This paper showed an adult chimpanzee a series of videotaped scenes of a human actor struggling with a variety of problems, some of which were simple, such as bananas vertically or horizontally out of reach, behind a box, and so forth; others were more complex, involving an actor unable to extricate himself from a locked cage, shivering because of a malfunctioning heater, or unable to play a phonograph because it was unplugged.
Abstract: An individual has a theory of mind if he imputes mental states to himself and others. A system of inferences of this kind is properly viewed as a theory because such states are not directly observable, and the system can be used to make predictions about the behavior of others. As to the mental states the chimpanzee may infer, consider those inferred by our own species, for example, purpose or intention, as well as knowledge, belief, thinking, doubt, guessing, pretending, liking, and so forth. To determine whether or not the chimpanzee infers states of this kind, we showed an adult chimpanzee a series of videotaped scenes of a human actor struggling with a variety of problems. Some problems were simple, involving inaccessible food – bananas vertically or horizontally out of reach, behind a box, and so forth – as in the original Kohler problems; others were more complex, involving an actor unable to extricate himself from a locked cage, shivering because of a malfunctioning heater, or unable to play a phonograph because it was unplugged. With each videotape the chimpanzee was given several photographs, one a solution to the problem, such as a stick for the inaccessible bananas, a key for the locked up actor, a lit wick for the malfunctioning heater. The chimpanzee's consistent choice of the correct photographs can be understood by assuming that the animal recognized the videotape as representing a problem, understood the actor's purpose, and chose alternatives compatible with that purpose.
5,979 citations
TL;DR: It is shown that a “greedy” heuristic always produces a solution whose value is at least 1 −[(K − 1/K]K times the optimal value, which can be achieved for eachK and has a limiting value of (e − 1)/e, where e is the base of the natural logarithm.
Abstract: LetN be a finite set andz be a real-valued function defined on the set of subsets ofN that satisfies z(S)+z(T)źz(SźT)+z(SźT) for allS, T inN. Such a function is called submodular. We consider the problem maxSźN{a(S):|S|≤K,z(S) submodular}.
Several hard combinatorial optimization problems can be posed in this framework. For example, the problem of finding a maximum weight independent set in a matroid, when the elements of the matroid are colored and the elements of the independent set can have no more thanK colors, is in this class. The uncapacitated location problem is a special case of this matroid optimization problem.
We analyze greedy and local improvement heuristics and a linear programming relaxation for this problem. Our results are worst case bounds on the quality of the approximations. For example, whenz(S) is nondecreasing andz(0) = 0, we show that a "greedy" heuristic always produces a solution whose value is at least 1 ź[(K ź 1)/K]K times the optimal value. This bound can be achieved for eachK and has a limiting value of (e ź 1)/e, where e is the base of the natural logarithm.
4,103 citations
TL;DR: The author reviews the current status and recent advances in segmentation research, covering segmentation problem definition, research design considerations, data collection approaches, data analysis procedures, and data interpretation and implementation.
Abstract: The author reviews the current status and recent advances in segmentation research, covering segmentation problem definition, research design considerations, data collection approaches, data analys
889 citations
TL;DR: In this article, the major glycolipid in myelin was used as a cell surface marker for cultured rat oligodendrocytes, the glial cells responsible for making myelin in the central nervous system.
Abstract: THE increasing use of tissue culture techniques in neurobiological studies has created an urgent need for cell-type specific markers which would allow unambiguous identification of the different types of neural cells. We show here that galactocerebroside (GC), the major glycolipid in myelin1, can serve as such a cell-surface marker for cultured rat oligodendrocytes, the glial cells responsible for making myelin in the central nervous system.
785 citations
TL;DR: A single representation of the cat's entire visual field corresponds closely to the cytoarchitectonically defined area 17, which is related to the locations of the corresponding recording sites in the cortex.
Abstract: The location and retinotopic organization of visual areas in the cat cortex were determined by systematically mapping visual cortex in over 100 cats. The positions of the receptive fields of single neurons or small clusters of neurons were related to the locations of the corresponding recording sites in the cortex to determine the representations of the visual field in these cortical areas. In this report, the first of a series, we describe the organization of area 17. A single representation of the cat's entire visual field corresponds closely to the cytoarchitectonically defined area 17. This area has the largest cortical surface area (380 mm2) and the highest cortical magnification factor (3.6 mm2/degree2 at area centralis) of all the cortical areas we have studied. There was perfect agreement between the borders of area 17 determined electrophysiologically and cytoarchitecturally. This area contains a first order transformation of the visual hemifield in which every adjacent point in the visual field is represented as an adjacent point in the cortex. Some variability exists among cats in the extent and retinotopic representation of the visual field in area 17.
747 citations
692 citations
TL;DR: The results emphasize the importance of trigeminal input in human nasal chemoreception and support the notion that the perceived intensities of nasally-inhaled stimulants can be mathematically predicted from relatively simple physicochemical and molecular structural parameters.
618 citations
TL;DR: This paper describes the somewhat more complex organization of the visual cortex lying on the banks of the middle and posterior suprasylvian sulci, which consists of six retinotopically organized units.
Abstract: This is the second in a series of papers in which we describe our continuing efforts to define functional units of visual cortex based upon electro-physiological mapping of single and multiple unit activity in both awake and the nitrous oxide anesthetized cats. In the first paper (Tusa, Palmer and Rosenquist, '78), the extent and retinotopic organization of area 17 were described. In this paper, we describe the somewhat more complex organization of the visual cortex lying on the banks of the middle and posterior suprasylvian sulci. This region of cortex consists of six retinotopically organized units. These areas are arranged as three roughly mirror symmetrical pairs separated in each case by the fundus of the middle or posterior suprasylvian sulci. Some thalamo-cortical autoradiographic material is presented which supports this parcellation of the cortex.
523 citations
TL;DR: The use of redistribution signals, which are slower, and thus more likely to represent to secondary effects of changes in membrane potential, and require permeant dyes with access to the internal millieu, may be more hazardous than the use of either fast or intrinsic signals.
Abstract: Optical measurement of membrane potential is a new tool for physiologists and has already found many applications. However, the number of possible pitfalls is alarming, particularly in situations where comparison with electrode measurements is impossible. Exhaustive and elaborate controls are clearly necessary; and yet they never provide complete assurance that an optical signal represents a change in membrane potential. In our opinion, the use of redistribution signals, which are slower, and thus more likely to represent to secondary effects of changes in membrane potential, and require permeant dyes with access to the internal millieu, may be more hazardous than the use of either fast or intrinsic signals. However, the larger size of the redistribution signals has endowed them with obvious appeal. If more sensitive fast signals can be found, the use of this kind of signal would be facilitated.
501 citations
TL;DR: Hemispheric asymmetry in the control over emotional expression in the face is indicated in the form of left-side and right-side composites.
Abstract: Pictures of human faces posing six distinct emotions (plus a neutral expression) and their mirror reversals were split down the midlines, and left-side and right-side composites were constructed. Subjects judged left-side composites as expressing emotions more intensely than right-side composites. The finding indicates hemispheric asymmetry in the control over emotional expression in the face.
478 citations
TL;DR: Food-deprived decerebrate rats, like intact ones, ingested a taste substance they had rejected when sated, but these same decerebrates neither rejected nor decreased ingestive reactions to a novel taste after that taste had been repeatedly paired with lithium chloride-induced illness.
Abstract: Taste substances applied to the oral cavity result in either ingestion or rejection, each with a characteristic muscular response pattern. These responses are the same in decerebrate and intact rats; the caudal brainstem appears to be the neural substrate of ingestion and rejection responses. The experiment determined whether decerebrates can alter these discriminative responses as a function of food deprivation or toxicosis. Food-deprived decerebrate rats, like intact ones, ingested a taste substance they had rejected when sated. However, these same decerebrates, in contrast to controls, neither rejected nor decreased ingestive reactions to a novel taste after that taste had been repeatedly paired with lithium chloride-induced illness. Although the forebrain may be important for integrating ingestion, some aspects of this control seem to be represented in caudal brain areas.
TL;DR: 14C- 2-deoxy-2-fluoro-D-glucose has been synthesized from 14C-3,4,6-tri-0-acetyl-D -glucal by fluorination with F2 and CF3OF to study of local cerebral glucose metabolism.
Abstract: A convenient method for the synthesis of 18F-2-deoxy-2-fluoro-D-glucose (4) and 18F-2-deoxy-2-fluoro-D-mannose (8) by the direct fluorination of 3,4,6-tri-0-acetyl-D-glucal with 18F-F2 is described. 14C-2-deoxy-2-fluoro-D-glucose has been synthesized from 14C-3,4,6-tri-0-acetyl-D-glucal (from D-[14c(U)]-glucose) by fluorination with F2 (Method 1) and CF3OF (Method 2). These labeled analogs of 2-deoxy-D-glucose were required for the study of local cerebral glucose metabolism.
TL;DR: A method for measuring the relativity of fuzziness by structuring the functions of a system hierarchically in a multiple objective framework and composing the eigenvectors into a priority vector which measures the fuzziness of the elements in the lowest level of the hierarchy.
TL;DR: A survey of the literature on rational expectations and the dynamic structure of macroeconomic models can be found in this paper, where a theoretical framework common to this literature is set forth for the reader unfamiliar with it.
TL;DR: A number of mechanisms are explored for modelling equilibrium values of attractiveness terms in production-constrained spatial-interaction models, including revenue and facility-size balancing, a differential-equation representation of profit maximisation, and mathematical-programming formulations.
Abstract: A number of mechanisms are explored for modelling equilibrium values of attractiveness terms in production-constrained spatial-interaction models. They include revenue and facility-size balancing, a differential-equation representation of profit maximisation, and mathematical-programming formulations. The different methods turn out to be closely related but offer different and complementary insights. Some dynamic properties of such equilibrium points are explored, including the identification of circumstances which generate discrete changes for smooth changes in parameters. A number of possible algorithms for calculating the points are described.
TL;DR: The United States is now at the start of a new period of growing scarcity of young adults as a result of the birth rate decline that set in after 1960, which implies that the 1980s will see a turnaround or amelioration in a wide variety of these social, political, and economic conditions.
Abstract: Since 1940, under conditions of restricted immigration and high and sustained growth in aggregate demand, shifts in the relative number of younger versus older adults have had a pervasive impact on American life. Before 1960, younger males were in increasingly short supply and their relative economic position substantially improved; after 1960, the opposite was true. Since the early sixties, as the relative condition of young adults has deteriorated, marriage has been increasingly deferred and fertility reduced. The labor force participation of young women has risen at above average rates, and that of older women has risen at below average rates. Changes in the age structure of the working age population have also contributed to a combination of rising unemployment and accelerating inflation. Cohort divorce rates, suicide among young males, crime rates, and political alienation have worsened. The rise in college enrollment rates has been interrupted, and SAT scores have declined. In contrast, in the period 1940–1960, changes in these various magnitudes were typically of a more favorable sort. The United States is now at the start of a new period of growing scarcity of young adults as a result of the birth rate decline that set in after 1960. This implies that the 1980s will see a turnaround or amelioration in a wide variety of these social, political, and economic conditions, some of which have been taken as symptomatic of a hardening social malaise.
TL;DR: In this article, the Toth adsorption isotherm was used to represent the data for aqueous single-solute adaption, and the thermodynamic ideal-adsorbed-solution method was applied to calculate the total and partial adsorptions.
TL;DR: In this article, a model of the diffusion process is developed which recognizes the interaction between adopters and non-adopters and the influence of external information sources such as advertising, and the model is extended by incorporating the effects of repeat purchasing.
Abstract: A model of the diffusion process is developed which recognizes 1 the interaction between adopters and non-adopters and 2 the influence of external information sources such as advertising. The model is extended by incorporating the effects of repeat purchasing. The models written by the following authors are shown to be special cases of this model: Gould. Nerlove and Arrow, Vidale and Wolfe, Palda, Bass, Nicosia, and Glaister. The behavioral assumptions which support the model are made explicit and the implications of these assumptions for the shape of the new product growth curve are derived.
TL;DR: The effects of annealing treatment on the physical properties of amorphous alloys obtained by splat cooling are discussed in this article, where three mechanisms, diffusion, topological short range ordering, and compositional short-range ordering, have been identified to cause these effects.
TL;DR: In this article, the atomic structure and structural relaxation of amorphous Fe40Ni40P14B6 alloy were studied using the energy dispersive X-ray diffraction method.
Abstract: The atomic structure and the structural relaxation of amorphous Fe40Ni40P14B6 alloy were studied using the energy dispersive X-ray diffraction method. It was demonstrated that the structure of the amorphous alloy can be determined self-consistently with high accuracy by this method. The results indicated that the structural relaxation is a highly collective process involving many atoms, and can be described in terms of the redistribution and transformation of the structural defects.
TL;DR: A sinusoidal shear generator developed by Miles (1962) is used to measure viscoelastic complex shear moduli for bovine articular cartilage and provides flow-independent measurements which are highly sensitive to biochemical alteration of the matrix constituents.
TL;DR: A new approach to scaling using largest eigenvalues and reciprocal matrices and the effect of inconsistent judgment are introduced and relevant theory discussed and both the eigenvalue approach to measurement and the hierarchical approach are illustrated.
TL;DR: Left side composites were judged to be more emotionally intense than right side Composites, which points to hemispheric asymmetry in the control of emotional expression and has implications for the role ofotional expression in communication.
TL;DR: In this article, economic, social, political and policy variables are tested for their significance in discriminating among three groups of developing countries designated "unattractive, moderately attractive, and highly attractive" with respect to foreign investment in manufacturing.
Abstract: Forty-four economic, social, political and policy variables are tested for their significance in discriminating among three groups of developing countries designated “unattractive,” “moderately attractive,” and “highly attractive” with respect to foreign investment in manufacturing. Among the six essential discriminators, the only policy variable to emerge is the corporate tax level.
TL;DR: Migration continues strong into the capital regions of the three Eastern European countries studied here (Poland, Hungary, and East Germany), however, the low natural increase of these regions has blunted their expansion.
Abstract: Of the eighteen countries studied in this paper eleven (Japan. Sweden Norway Italy Denmark New Zealand. Belgium France West Germany East Germany and The Netherlands) show either a reversal in the direction of net population flow from their sparsely populated peripheral regions to their densely populated core regions or a drastic reduction in the level of this net flow. In the first seven of these eleven countries this reversal or reduction became evident only in the 1970s; in the last four its onset was recorded in the 1960s. Six countries (Hungary Spain Finland Poland. South Korea and Taiwan) have yet to show an attenuation in the movement of persons into their most densely populated regions. Some possibly unreliable British data likewise fail to reveal a slackening in the "drift south" of the British population. Three additional discoveries described in this paper are the following: (1) Migration continues strong into the capital regions of the three Eastern European countries studied here (Poland Hungary and East Germany). However the low natural increase of these regions has blunted their expansion. (2) Though domestic migration into the capital regions of France. Sweden and Norway has declined dramatically foreign immigration into these regions remains at a high level. (3) Net domestic migration into the core regions of Sweden Japan and Italy countries separated by vast distances fluctuate from year to year in a remarkably similar manner. (authors)
TL;DR: The detectability of compound gratings containing two sinusoidal components was compared to that of each component alone and the results are consistent with models postulating several sizes of receptive fields at each position in the visual field but not with model postulating only one size at each positions.
TL;DR: Prostacyclin, a potent, naturally occurring prostaglandin exerts a variety of cardiovascular and cellular actions of potential value in acute myocardial ischemia, which include the reduction of systemic blood pressure without changing heart rate.
Abstract: Prostacyclin, a potent, naturally occurring prostaglandin exerts a variety of cardiovascular and cellular actions of potential value in acute myocardial ischemia. These properties include the reduction of systemic blood pressure without changing heart rate, the lowering of coronary vascular and total peripheral resistance, the inhibition of platelet aggregation and the concomitant formation of thromboxane B2, and the reduction of the release of lysosomal enzymes.
TL;DR: A factorial design demonstrated that the female Norway rat has the major role determining the amount and timing of copulation once mating begins, and the population pattern of a wild female was characterized by fewer ejaculatory series and more intromissions at longer intervals before the first ejaculation than the patterns of a domestic female.
Abstract: The copulatory behavior of both wild and domestic strains of Rattus norvegicus was observed via continuous video monitoring as it spontaneously occurred in the large seminatural environment and under standard laboratory conditions. A factorial design demonstrated that the female Norway rat has the major role determining the amount and timing of copulation once mating begins. Copulation between wild pairs was characterized by fewer ejaculatory series than domestic pairs. The first ejaculatory series of wild pairs contained more intromissions at longer intervals. Domestic pairs had the same total number of intromissions in a copulatory session, but spread over multiple ejaculatory series with few intromissions at short intervals in the first series. The characteristic differences between the copulatory patterns of wild and domestic pairs was determined by the female's strain condition and was either statistically independent or opposite to the male's strain condition. Specifically, the population pattern of a wild female was characterized by fewer ejaculatory series and more intromissions at longer intervals before the first ejaculation than the pattern of a domestic female. These differences between wild and domestic populations were produced by differences in the rate of active solicitations for an intromission by individual females : the solicitation occurred virtually in a one-to-one correspondence with an intromission. There were no gross anatomical differences between the vaginal size and placement of the two strains. The female solicitation is a distinct and quantifiable behavior not found in the standard testing cage: its occurrence depends on a larger and more complex environment. In addition, copulation in the larger seminatural environment is characterized by fewer intromissions in each ejaculatory series of a session at longer copulatory intervals. The role of the female is discussed both in terms of the individual interactions which underlie it and in terms of its physiological functions for successful reproduction in the rat. Copulation with a wild male is characterized by longer intervals between the intromissions of the first ejaculatory series than with a domestic male. The wild condition of both the pair and the female showed the opposite effect. This difference is evaluated in terms of the different mating strategies for the two sexes on a population level and in terms of the individual interactions that allow a compromise for successful reproduction of the pair.