Showing papers by "Cornell University published in 1982"

Accommodation of a scientific conception: Toward a theory of conceptual change

Abstract: It has become a commonplace belief that learning is the result of the interaction between what the student is taught and his current ideas or concepts.’ This is by no means a new view of learning. Its roots can be traced back to early Gestalt psychologists. However, Piaget’s (1929, 1930) early studies of children’s explanations of natural phenomena and his more recent studies of causality (Piaget, 1974) have perhaps had the greatest impact on the study of the interpretive frameworks students bring to learning situations. This research has led to the widespread study of students’ scientific misconceptions.2 From these studies and, particularly, from recent work by researchers such as Viennot ( 1979) and Driver (1 973), we have developed a more detailed understanding of some of these misconceptions and, more importantly, why they are so “highly robust” and typically outlive teaching which contradicts them (Viennot, 1979, p. 205). But identifying misconceptions or, more broadly speaking, “alternative frameworks” (Driver & Easley, 1978), and understanding some reasons for their persistence, falls short of developing a reasonable view of how a student’s current ideas interact with new, incompatible ideas. Although Piaget (1974) developed one such theory, there appears to be a need for work which focuses “more on the actual content of the pupil’s ideas and less on the supposed underlying logical structures” (Driver & Easley, 1978, p. 76). Several research studies have been performed (Nussbaum, 1979; Nussbaum & Novak, 1976; Driver, 1973; Erickson, 1979) which have investigated “the substance of the actual beliefs and concepts held by children” (Erickson, 1979, p. 221). However, there has been no well-articulated theory explaining or describing the substantive dimensions of the process by which people’s central, organizing concepts change from one set of concepts to another set, incompatible with the first. We believe that a major source of hypotheses concerning this issue is contemporary philosophy of science, since a central question of recent philosophy of science is how concepts change under the impact of new ideas or new information. In this article we first sketch a general model of conceptual change which is largely derived from current philosophy of science, but which we believe can illuminate * This article is partly based on a paper entitled “Learning Special Relativity: A Study of Intellectual Problems Faced by College Students,” presented at the International Conference Celebrating the 100th Anniversary of Albert Einstein, November 8-10, 1979 at Hofstra University.

Temporal profile of neuronal damage in a model of transient forebrain ischemia.

Abstract: This study examined the temporal profile of ischemic neuronal damage following transient bilateral forebrain ischemia in the rat model of four-vessel occlusion. Wistar rats were subjected to transient but severe forebrain ischemia by permanently occluding the vertebral arteries and 24 hours later temporarily occluding the common carotid arteries for 10, 20, or 30 minutes. Carotid artery blood flow was restored and the rats were killed by perfusion-fixation after 3, 6, 24, and 72 hours. Rats with postischemic convulsions were discarded. Ischemic neuronal damage was graded in accordance with conventional neuropathological criteria. Ten minutes of four-vessel occlusion produced scattered ischemic cell change in the cerebral hemispheres of most rats. The time to onset of visible neuronal damage varied among brain regions and in some regions progressively worsened with time. After 30 minutes of ischemia, small to medium-sized striatal neurons were damaged early while the initiation of visible damage to hippocampal neurons in the h1 zone was delayed for 3 to 6 hours. The number of damaged neurons in neocortex (layer 3, layers 5 and 6, or both) and hippocampus (h1, h3-5, paramedian zone) increased significantly (p less than 0.01) between 24 and 72 hours. The unique delay in onset of ischemic cell change and the protracted increase in its incidence between 24 and 72 hours could reflect either delayed appearance of ischemic change in previously killed neurons or a delayed insult that continued to jeopardize compromised but otherwise viable neurons during the postischemic period.

A Reflectance Model for Computer Graphics

Abstract: This paper presents a new reflectance model for rendering computer synthesized images. The model accounts for the relative brightness of different materials and light sources in the same scene. It describes the directional distribution of the reflected light and a color shift that occurs as the reflectance changes with incidence angle. The paper presents a method for obtaining the spectral energy distribution of the light reflected from an object made of a specific real material and discusses a procedure for accurately reproducing the color associated with the spectral energy distribution. The model is applied to the simulation of a metal and a plastic.

Building Bridges Between Inorganic and Organic Chemistry (Nobel Lecture)

Abstract: Robert B. Woodward, a supreme patterner of chaos, was one of my teachers. I dedicate this lecture to him, for it is our collaboration on orbital symmetry conservation, the electronic factors which govern the course of chemical reactions, which is recognized by half of the 1981 Nobel Prize in Chemistry. From Woodward I learned much: the significance of the experimental stimulus to theory, the craft of constructing explanations, and the importance of asethetics in science. I will try to show you how these characteristics of chemical theory may be applied to the construction of conceptual bridges between inorganic and organic chemistry.

A Remnant of Chiral Symmetry on the Lattice

Abstract: A new criterion for chiral symmetry in lattice theories of fermions is derived within a block-spin formalism This "remnant" symmetry criterion properly incorporates the Adler Bell-Jackiw anomaly and avoids the fermion-doubling problem of other lattice fermion methods Some obstacles to implementing this approach in the presence of fully dynamical gauge fields are discussed

Peer-review practices of psychological journals: The fate of published articles, submitted again

Abstract: A growing interest in and concern about the adequacy and fairness of modern peer-review practices in publication and funding are apparent across a wide range of scientific disciplines. Although questions about reliability, accountability, reviewer bias, and competence have been raised, there has been very little direct research on these variables.The present investigation was an attempt to study the peer-review process directly, in the natural setting of actual journal referee evaluations of submitted manuscripts. As test materials we selected 12 already published research articles by investigators from prestigious and highly productive American psychology departments, one article from each of 12 highly regarded and widely read American psychology journals with high rejection rates (80%) and nonblind refereeing practices.With fictitious names and institutions substituted for the original ones (e.g., Tri-Valley Center for Human Potential), the altered manuscripts were formally resubmitted to the journals that had originally refereed and published them 18 to 32 months earlier. Of the sample of 38 editors and reviewers, only three (8%) detected the resubmissions. This result allowed nine of the 12 articles to continue through the review process to receive an actual evaluation: eight of the nine were rejected. Sixteen of the 18 referees (89%) recommended against publication and the editors concurred. The grounds for rejection were in many cases described as “serious methodological flaws.” A number of possible interpretations of these data are reviewed and evaluated.

A new look at the saturn system: the voyager 2 images.

Abstract: Voyager 2 photography has complemented that of Voyager I in revealing many additional characteristics of Saturn and its satellites and rings. Saturn's atmosphere contains persistent oval cloud features reminiscent of features on Jupiter. Smaller irregular features track out a pattern of zonal winds that is symmetric about Saturn's equator and appears to extend to great depth. Winds are predominantly eastward and reach 500 meters per second at the equator. Titan has several haze layers with significantly varying optical properties and a northern polar "collar" that is dark at short wavelengths. Several satellites have been photographed at substantially improved resolution. Enceladus' surface ranges from old, densely cratered terrain to relatively young, uncratered plains crossed by grooves and faults. Tethys has a crater 400 kilometers in diameter whose floor has domed to match Tethys' surface curvature and a deep trench that extends at least 270° around Tethys' circumference. Hyperion is cratered and irregular in shape. Iapetus' bright, trailing hemisphere includes several dark-floored craters, and Phoebe has a very low albedo and rotates in the direction opposite to that of its orbital revolution with a period of 9 hours. Within Saturn's rings, the "birth" of a spoke has been observed, and surprising azimuthal and time variability is found in the ringlet structure of the outer B ring. These observations lead to speculations about Saturn's internal structure and about the collisional and thermal history of the rings and satellites.

Linkage of β-thalassaemia mutations and β-globin gene polymorphisms with DNA polymorphisms in human β-globin gene cluster

Abstract: Combined analysis of DNA polymorphisms in the human β-globin gene cluster and in cloned β-genes has revealed the association of specific β-thalassaemia mutations and β-gene polymorphisms with particular flanking polymorphisms. A systematic study of cloned genes identified several new mutations, one of which possibly affects transcription. The strategy used may be applicable to other diseases of single-copy genes.

Tracing the dynamic changes in perceived tonal organization in a spatial representation of musical keys.

Abstract: The cognitive representation of harmonic and tonal structure in Western music is investigated using a tone-profile technique. In this method listeners rate how well single tones (any one of the 12 tones of the chromatic scale) follow a musical element such as a scale, chord, or cadence. Very stable rating profiles reflecting the tonal hierarchies in major and minor keys are obtained, which, when intercorrelated and analyzed using multidimensional scaling, produce a four-dimensional spatial map of the distances between keys. The keys are located on the surface of a torus, in which the circle of fifths and the parallel and relative relations between major and minor keys are represented. In addition, single chords (major, minor, diminished, and dominant seventh) are found to be closely associated with the major and minor keys in which they play harmonic functions. The developing and changing sense of key during sequences of chords is traced by obtaining probe tone ratings following each chord in 10 different sequences, 8 of which contain modulations (changes) between keys. Modulations between closely related keys are found to be effected more immediately than are modulations between relatively distant keys. In all cases beyond the initial chord, the sense of the prevailing key is stronger than that produced by the last heard chord in isolation. Thus, listeners integrate harmonic functions over multiple chords, developing a sense of key that may need to be reevaluated as additional chords are sounded. It is suggested that the perceived relations between chords and keys and between different keys are mediated through an internal representation of the hierarchy of tonal functions of single tones in music. Music consists of tones varying in pitch, serve to highlight rhythmic patterns, further duration, loudness, and timbre, but the per- emphasize phrase structure, and distinguish ception of music extends well beyond the between tones constituting the primary meregistration of these physical attributes of lodic line and tones serving more ornamental the musical stimulus. Indeed, music contains or harmonic functions. Timbral characterconsiderable structure even in the relations istics may additionally provide important that obtain among the individual tones. For cues for the overall structure of the musical example, the durations are such that metri- composition.

Commercial Use of Conjoint Analysis: A Survey:

Abstract: Conjoint analysis has been used extensively in marketing research to estimate the impact of selected product (service) characteristics on customer preferences for products (services). In this paper...

Principles of Polymer Systems

Abstract: 1. Introduction 2. Basic Structures of Polymers 3. Physical States and Transitions 4. Polymer Formation 5. Polymerization Processes 6. The Molecular Weight of Polymers 7. Viscous Flow 8. Mechanical Properties at Small Deformations 9. Ultimate Properties 10. Some General Properties of Polymer Systems 11. Degradation and Stabilization of Polymer Systems 12. Fabrication Processes 13. Extrusion and Molding 14. Recycling and Resource Recovery 15. Carbon Chain Polymers 16. Heterochain Polymers 17. Analysis and Identification of Polymers Appendix 1. List of symbols Appendix 2. Harmonic motion of a Maxwell model Appendix 3. Selected properties of polymer systems Appendix 4. Major Markets for selected plastics and rubber

K o - OCR Relationships in Soil

Abstract: The relationships between K o and OCR are investigated for primary loading - unloading - reloading conditions. The study reviews laboratory data from over 170 different soils and presents an approach common to clays, silts and sands. Simple empirical methods for predicting K o for normally consolidated and overconsolidated soils are evaluated. The validity of the methods is supported by statistical analyses. On the basis of the findings, only the effective stress friction angle (O') and prior stress history (OCR and OCRmax) are needed to predict approximate values of K o .

Study of the L 23 edges in the 3 d transition metals and their oxides by electron-energy-loss spectroscopy with comparisons to theory

Abstract: Excitations of the $2p$ subshell in the $3d$ transition metals and their oxides have been studied by inelastic scattering of 75-keV electrons. The ${L}_{23}$ "white lines" which arise from dipole transitions to unoccupied $d$ states have been investigated in terms of their threshold energies, widths, and intensity ratios. Shifts in the ${L}_{3}$ threshold energy between the metal and oxide are different from the chemical shifts measured by x-ray photoemission spectroscopy and this suggests the importance of relaxation effects. Single-particle calculations for the ${L}_{3}$ spectra are also discussed. Measured ${L}_{3}$ linewidths are generally larger than those predicted by suitably broadened theory. A variation from the statistical ${L}_{3}$-to-${L}_{2}$ white-line intensity ratio of 2:1 has been observed across the $3d$ transition row, with values ranging between 0.8:1 for Ti to 5:1 for FeO. This behavior appears to be associated with the white lines since Cu with a filled $3d$ band exhibits the statistical results. It is suggested that the anomalous ratios may be explained by a breakdown of $j\ensuremath{-}j$ coupling caused by an exchange mechanism. Finally, the extended x-ray absorption fine-structure-type structure extending several hundred eV above the white lines is analyzed for Cr to provide the radial distribution function.

Convergence of autonomic and limbic connections in the insular cortex of the rat.

Abstract: The connections of the insular cortex in the rat were studied by using the anterograde and retrograde transport of wheat germ agglutinin-conjugated-horseradish peroxidase. Both anterograde and retrograde transport were seen in the ipsilateral lateral frontal, infralimbic, piriform, and perirhinal cortical areas and in the contralateral insular cortex. In the thalamus, both types of labeling were seen in the mediodorsal and ventroposteromedial parvocellular nuclei; primarily retrograde labeling was seen in the centromedial and paracentral nuclei. In the basal forebrain, anterograde labeling was seen in the lateral part of the bed nucleus of the stria terminalis and in the central nucleus of the amygdala, while retrogradely labeled neurons were found in the magnocellular basal nucleus and in the lateral and the basolateral amygdaloid nuclei. Both types of labeling were seen in the posterior lateral hypothalamic area; the tuberomammillary nucleus contained retrogradely labeled neurons bilaterally. In the midbrain, retrogradely labeled neurons were found in the ventral tegmental area and in the dorsal and superior central raphe nuclei. In the pons, both retrogradely and anterogradely transported label was seen bilaterally in the parabrachial nucleus, primarily in the ventromedial caudal part of the medial subnucleus. Retrogradely labeled neurons were found bilaterally in the locus coeruleus. Anterograde transport was followed into the medulla, bilaterally but more heavily in the contralateral side. Labeled axons appeared to terminate in a topographic pattern in the nucleus of the solitary tract. These results indicate that the insular cortex of the rat is an important part of the highly interconnected central autonomic system. Furthermore, the autonomic representation in the insular cortex may be organized in a viscerotopic manner. The insular cortex also has connections with the limbic system and with the lateral frontal cortical system. Although it is not yet clear whether these connections converge upon the same neurons within the insular cortex, earlier physiological data suggest that each of the diverse systems of connections of this area receives relayed vagal inputs. The insular cortex of the rat may contain a primary cortical visceral representation, and its connections may underlie autonomic integration with behavioral and emotional events.

Aluminum Toxicity to Fish in Acidic Waters

Abstract: An important consequence of acidification is the mobilization of Al from the edaphic to the aquatic environment. Elevated Al levels in acidic waters may be toxic to fish. Eggs, larvae, and postlarvae of white suckers (Catostomus commersoni) and brook trout (Salvelinus fontinalis) were exposed in laboratory bioassays to pH levels 4.2 to 5.6 and inorganic Al concentrations of 0 to 0.5 mg l−1. Aluminum toxicity varied with both pH and life history stage. At low pH levels (4.2 to 4.8), the presence of Al (up 0.2 mg l−1 for white suckers; 0.5 mg l−1 for brook trout) was beneficial to egg survival through the eyed stage. In contrast, Al concentrations of 0.1 mg l−1 (for white suckers) or 0.2 mg l−1 (for brook trout) and greater resulted in measurable reductions in survival and growth of larvae and postlarvae at all pH levels (4.2 to 5.6). Aluminum was most toxic in over-saturated solutions at pH levels 5.2 to 5.4. The simultaneous increase in Al concentration with elevated acidity must be considered to accurately assess the potential effect of acidification of surface waters on survival of fish populations.

The nature of the coupling between segmental oscillators of the lamprey spinal generator for locomotion: a mathematical model.

Abstract: We present a theoretical model which is used to explain the intersegmental coordination of the neural networks responsible for generating locomotion in the isolated spinal cord of lamprey.

Regional cerebral blood flow and glucose metabolism following transient forebrain ischemia.

Abstract: Progressive brain damage after transient cerebral ischemia may be related to changes in postischemic cerebral blood flow and metabolism. Regional cerebral blood flow (rCBF) and cerebral glucose utilization (rCGU) were measured in adult rats prior to, during (only rCBF), and serially after transient forebrain ischemia. Animals were subjected to 30 minutes of forebrain ischemia by occluding both common carotid arteries 24 hours after cauterizing the vertebral arteries. Regional CBF was measured by the indicator-fractionation technique using 4-iodo-[14C]-antipyrine. Regional CGU was measured by the 2-[14C]deoxyglucose method. The results were correlated with the distribution and progression of ischemic neuronal damage in animals subjected to an identical ischemic insult. Cerebral blood flow to forebrain after 30 minutes of moderate to severe ischemia (less than 10% control CBF) was characterized by 5 to 15 minutes of hyperemia; rCBF then fell below normal and remained low for as long as 24 hours. Post-ischemic glucose utilization in the forebrain, except in the hippocampus, was depressed below control values at 1 hour and either remained low (neocortex, striatum) or gradually rose to normal (white matter) by 48 hours. In the hippocampus, glucose utilization equaled the control value at 1 hour and fell below control between 24 and 48 hours. The appearance of moderate to severe morphological damage in striatum and hippocampus coincided with a late rise of rCBF above normal and with a fall of rCGU; the late depression of rCGU was usually preceded by a period during which metabolism was increased relative to adjacent tissue. Further refinement of these studies may help identify salvageable brain after ischemia and define ways to manipulate CBF and metabolism in the treatment of stroke.

Blood Pressure During Normal Daily Activities, Sleep, and Exercise: Comparison of Values in Normal and Hypertensive Subjects

Abstract: Blood pressure (BP) readings were taken every 15 minutes using a noninvasive ambulatory BP recorder during 24 hours in 25 subjects with normal BP, 25 with borderline hypertension, and 25 with established essential hypertension. Readings were analyzed for four situations: (1) physician's office, (2) work, (3) at home, and (4) asleep. Treadmill exercise tests were also performed on a separate occasion with the Bruce protocol. The 24-hour recording in all three groups showed the highest BPs at work and the lowest during sleep. The situational BP changes were generally similar, but both hypertensive groups differed from normal subjects in that they showed consistently higher BPs in the physician's office than at home, whereas normal subjects showed little difference. During exercise, the hypertensive groups showed a similar rise of systolic pressure to that of normal subjects. Pressures recorded in the physician's office gave good predictions of the average 24-hour pressure in normal and established hypertensive subjects, but not in the borderline group; in such patients, 24-hour monitoring may be of particular value in establishing the need for treatment. ( JAMA 1982;247:992-996)

The Ontogeny of Kin Recognition in Two Species of Ground Squirrels1

Abstract: SYNOPSIS. We report results of a three year comparative laboratory study of kin recognition abilities in Arctic ground squirrels ( Spermophilus parryii ) and Belding's ground squirrels ( S. beldingi ), and a field investigation of kin recognition in S. beldingi . Our laboratory work shows that in both species, preweaned pups reared together, whether they are biological siblings or cross-fostered (unrelated) nestmates, are equally aggressive in subsequent paired arena tests. Thus, pups that share a natal nest are treated like siblings. Among pups reared apart, sister-sister pairs are less aggressive in arena tests than are pairs of nonkin females, whereas relatedness does not affect male-male or male-female aggression. Thus both relatedness and rearing environment mediate recognition among female S. parryii and S. beldingi . In free-living Belding's ground squirrels at Tioga Pass, California, dam-offspring and sister-sister recognition apparently first occur at weaning, coincident with aboveground emergence of juveniles. Most intriguing (electrophoretically identified) littermate full-sisters and maternal half-sisters, which result from multiple mating by females, seem to treat each other differently despite having shared a natal nest. The full-sisters are less agonistic and more cooperative than the half-sisters. In interpreting these laboratory and field results, we explore four proximal mechanisms by which kin might be identified, including one in which recognition is based on (learned) phenotypic similarity to an individual's nestmates or itself (phenotype matching). Our data and those of several recent investigators of recognition in other taxa implicate both association with relatives and phenotype matching in the ontogeny of kin recognition.

Oxytocin receptors and human parturition: a dual role for oxytocin in the initiation of labor

Abstract: The concentration of oxytocin receptors increased in the myometrium of pregnant women and reached maximum levels in early labor. Concentrations of oxytocin receptors were also high in the decidua and reached a maximum at parturition. In vitro, prostaglandin production by the decidua, but not by the myometrium, was increased by the addition of oxytocin. Oxytocin may therefore stimulate uterine contractions by acting both directly on the myometrium and indirectly on decidual prostaglandin production. Oxytocin receptors are probably crucial for the onset of human labor, and the stimulus for the increase in uterine prostaglandins may be oxytocin originating from the fetus.

Distribution of dopamine-, noradrenaline-, and adrenaline-containing cell bodies in the rat medulla oblongata: demonstrated by the immunocytochemical localization of catecholamine biosynthetic enzymes.

Abstract: The immunocytochemical localization of the biosynthetic enzymes--tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH), and phenylethanolamine-N-methyltransferase (PNMT)--was used to determine the cytological features and precise neuroanatomical location of catecholaminergic neurons in the medulla oblongata of rat. Perikarya labeled with TH were detected in two bilaterally symmetrical columns located in the ventrolateral and dorsomedial medulla. The distribution and the number of neuronal perikarya containing TH were the same as those containing DBH, except in the dorsal motor nucleus of the vagus at the level of the area postrema where the number of neurons immunocytochemically labeled for TH was considerably greater than those labeled for DBH. The detection of perikarya which show immunoreactivity for TH, used in the biosynthesis of dopamine, noradrenaline, and adrenaline, but not DBH, which converts dopamine to noradrenaline, suggests the existence of dopamine-synthesizing neurons in the medulla. Perikarya labeled with PNMT, used in the biosynthesis of adrenaline, were localized in more restricted regions corresponding to rostral subsets of the dorsal and ventral groups labeled for TH and DBH. Counts of neurons immunocytochemically labeled for TH or PNMT were obtained in order to determine the relative ratio of neurons which contain the enzymes necessary for the synthesis of dopamine, noradrenaline, or adrenaline at various levels of the medulla. At the most caudal levels no PNMT labeled neurons were detected. Further rostral, PNMT-labeled neurons were first detected in the ventrolateral medulla. At the level of the area postrema, the number of PNMT-labeled neurons in the ventrolateral medulla was approximately half of the number of cells showing immunoreactivity for TH. In contrast, few PNMT-labeled cells were detected in the dorsomedial medulla at the level of the area postrema compared to many neurons labeled for TH. At rostral medullary levels, in both the ventrolateral and the dorsomedial regions, the number of neurons labeled for TH and PNMT was essentially the same. Thus most, if not all, of the catecholaminergic neurons in the rostral medulla have PNMT, necessary for the synthesis of adrenaline.

Compositional Structure of the Asteroid Belt

Abstract: The distribution of compositional types among the asteroids is found to vary systematically with heliocentric distance. Seven distinct peaks in the relative proportion of the compositional types E, R, S, M, F, C, P, and D are found from 1.8 to 5.2 astronomical units. The inferred composition of the asteroids in each semimajor axis region is consistent with the theory that the asteroids accreted from the solar nebula at or near their present locations.

Multicriticality of Wetting, Prewetting, and Surface Transitions

Abstract: The global phase diagram for wall and surface critical phenomena is analyzed in the space of temperature, surface enhancement, and bulk and surface fields, on the basis of Landau phenomenological theory. Features probably valid for various real systems are the physical unity of prewetting and pure surface criticality, and novel exponents for critical wetting and for a wetting tricritical point, which terminates the region of normal first-order wetting.