Showing papers by "Dartmouth College published in 1976"
Journal Article•
305 citations
TL;DR: It is postulated herein: that a basic anomaly, possibly related to the genetic disorder affects primarily some cortical neurons which undergo progressive degenerative changes terminating in cell fragmentation and death.
Abstract: The neuronal organization of the motor cortex of a 19-month old child with Down's syndrome (mongolism) has been studied with the rapid Golgi method. This congenital syndrome, also known as 21 Trisomy is caused by a chromosomal abnormality consisting of the presence of an extra chromosome in the group 21. Various structural abnormalities have been found in the dendritic spines (postsynaptic structures) of the pyramidal neurons of the motor cortex of this child. The axo-spinous synapses of these neurons are considered to be altered by these spine abnormalities. In addition, a peculiar form of intrinsic vacuolar change affecting the dendrites and scattered neuronal fragmentation and necrosis have also been found. At least three different types of abnormality involving the spines — (the unusually long spine, the very short spine and a reduction in the number of spines) — are recognized among the pyramidal cells of the motor cortex. It is postulated herein: that a basic anomaly, possibly related to the genetic disorder affects primarily some cortical neurons which undergo progressive degenerative changes terminating in cell fragmentation and death. The different spine abnormalities are considered to represent various developmental stages of the common genetic anomaly. These changes might be structural correlates of the motor incoordination and mental retardation which are characteristic of this genetic disorder, but, final conclusions should await the investigation of other cases with this or similar methods capable of demonstrating the normal as well as the abnormal structural organization of the human cerebral cortex.
276 citations
TL;DR: The findings support theories of emotion that assume that expressive responses serve a self-regulatory as well as a social-communicative function, and suggest that the self-regulation is mediated neurally, rather than via a process of self-attribution.
Abstract: Three studies are reported that examine the relationship between the nonverbal display of emotional affect and indices of the emotional state. Subjects were asked either to conceal or to exaggerate the facial display associated with the anticipation and reception of painful shocks that varied in intensity. Both self-reports of shock painfulness and skin conductance measures of emotional response showed significant changes paralleling the changes induced in expressive behavior; that is, the suppression of expressive responses decreased the magnitude of phasic skin conductance changes and subjective reports of painfulness as compared to the free expression or exaggeration of pain-related expressive response. The effects were obtained for shocks of varying intensities and for both male and female subjects. The findings support theories of emotion that assume that expressive responses serve a self-regulatory as well as a social-communicative function, and further suggest that the self-regulation is mediated neurally, rather than via a process of self-attribution. Finally, the results highlight the need for research on dissimulation in social interaction to consider the effects of acting upon the actor, as well as its effects upon the inferences of observers.
245 citations
TL;DR: Situs inversus viscerum in the mouse has been shown to be inherited as an autosomal recessive trait (gene symbol iv) with reduced penetrance and it is hypothesized that the normal allele at the iv locus exhibits complete dominance and controls normal visceral asymmetry.
Abstract: Situs inversus viscerum in the mouse has been shown to be inherited as an autosomal recessive trait (gene symbol iv) with reduced penetrance. It is hypothesized that the normal allele at the iv locus exhibits complete dominance and controls normal visceral asymmetry. Absence of this control allows the situs of visceral asymmetry to be determined in a random fashion. This hypothesis also appears to apply to the inheritance of situs inversus in man and to the experimental production of situs inversus.
230 citations
TL;DR: Toxoplasma gondii, strain RH, produced plaques in human fibroblast tissue cultures over the temperatures 30–41 C, and both mutants that were tested were found to be markedly less virulent for mice than was the wild type RH strain.
208 citations
TL;DR: In this paper, the authors employ an iterative reduction scheme, free of assumptions, and calculate formally exact corrections to the Smoluchowski equations for manyparticle systems with and without hydrodynamic interaction, and for a single particle in an external field.
Abstract: Differential equations governing the time evolution of distribution functions for Brownian motion in the full phase space were first derived independently by Klein and Kramers. From these so-called Fokker-Planck equations one may derive the reduced differential equations in coordinate space known as Smoluchowski equations. Many such derivations have previously been reported, but these either involved unnecessary assumptions or approximations, or were performed incompletely. We employ an iterative reduction scheme, free of assumptions, and calculate formally exact corrections to the Smoluchowski equations for many-particle systems with and without hydrodynamic interaction, and for a single particle in an external field. In the absence of hydrodynamic interaction, the lowest order corrections have been expressed explicitly in terms of the coordinate space distribution function. An additional application of the method is made to the reduction of the stress tensor used in evaluating the intrinsic viscosity of particles in solution. Most of the present work is based on classical Brownian motion theory, but brief consideration is given in an appendix to some recent developments regarding non-Markovian equations for Brownian motion.
207 citations
TL;DR: The attenuation of expressive behavior was accompanied by a general decrease in subjective and autonomic responses to the painful stimuli, and an interpretation is discussed for the effect of observation on expressive behavior and for the relationships observed among expressive, autonomic, and subjective indices of pain.
Abstract: Two experiments explored the effects of observation by another on responses to painful stimuli. It was anticipated that the intensity of pain-related non-verbal expressivity decreases under observation, while indices of arousal (skin conductance and self-report) increase. In Experiment 1, subjects' expressive responses to shock were attenuated when subjects were observed as compared to when they were alone, but the anticipated augmentation of arousal did not occur. Rather, the attenuation of expressive behavior was accompanied by a general decrease in subjective and autonomic responses to the painful stimuli. A second experiment replicated the results of the first study and, in addition, found no evidence for a differential impact of sex of observer on the three measures of arousal. An interpretation is discussed for the effect of observation on expressive behavior and for the relationships observed among expressive, autonomic, and subjective indices of pain.
192 citations
TL;DR: This article found evidence for egotism in the attribution of good outcomes to one's skill rather than to luck in an experiment designed to demonstrate ego-motivated behavior in a competition setting.
Abstract: Egotism is defined as the tendency to make attributions that put oneself in the best possible light, for example, the attribution of good outcomes to one's skill rather than to luck. An experiment was designed to demonstrate egotism. To rule out alternative explanations, the experiment compared the attributions of actors and observers for both good and bad outcomes. Theoretical considerations suggested that egotism might be especially likely at the conclusion of competition. Hence, subjects competed, won, or lost and then made attributions for their own and their opponents' outcomes. Evidence for egotism was clear. In addition, subjects made predictions of their opponents' attributions, which often turned out to be fairly accurate.
182 citations
163 citations
TL;DR: The Angareb Ring Dike Complex is located in Begemder Province in northwestern Ethiopia, 55 kilometers NNW of the provincial capital Gondar as discussed by the authors, and was first identified in 1973 from Landsat 1 satellite imagery analysis of the East African Rift System.
Abstract: The Angareb Ring Dike Complex is located in Begemder Province in northwestern Ethiopia, 55 kilometers NNW of the provincial capital Gondar. The structure was first identified in 1973 from Landsat 1 satellite imagery analysis of the East African Rift System.
136 citations
TL;DR: In this paper, an estimate of the electron-phonon contribution to the electrical resistivity of copper at temperatures below 8 K and of silver below 5 K is presented. But the experimental results for gold below about 4 K are not yet available.
Abstract: Recently observed behavior in the electrical resistivity of copper at temperatures below 8 K and of silver below 5 K is interpreted as arising from electron-electron scattering. Similar behavior is predicted for gold below about 4 K, where data are not yet available. An estimate of the electron-phonon contribution shows that its ${T}^{5}$ asymptote is approached in the regime where electron-electron scattering is important.
TL;DR: It seems that epiphytic lichens have potential ecological importance in altering the chemistry of throughfall and stemflow.
Abstract: Epiphytic lichen growth is abundant on the boles and branches of balsam fir trees at high elevations in New Hampshire. These lichens absorb elements needed for growth from solutions flowing over their surfaces and from direct impaction of water droplets. This study describes how epiphytic lichens and fir needles altered the chemistry of simulated rain water solutions under laboratory conditions. Experiments showed: 1) lichens absorbed ammonium and nitrate from solution; the rate of uptake increased with increasing temperature of the solution, 2) lichens lost calcium, magnesium, and hydrogen to the solution, 3) lichen thalli also initially lost potassium, but in time, net movement was reversed back into the thallus, 4) cation movement increased with increasing temperature, and 5) fir needles responded in a manner similar to that of the lichens, but the amount of change was much less. From these results it seems that epiphytic lichens have potential ecological importance in altering the chemistry of throughfall and stemflow.
TL;DR: In this paper, it was proved that φ4 ≠ 0, and a way was found of associating stationary sets with most of the types in φ 4 which is useful for applications.
Journal Article•
TL;DR: Psychiatric consultation-liaison services offer the most direct form of collaboration between psychiatry and medicine in the interests of comprehensive patient care and greater emphasis on teaching psychiatric syndromes is called for.
Abstract: 1,000 medical and surgical inpatients referred for psychiatric conSULTATION SHOWED CONCURRENT PHYSICAL AND PSYCHIATRIC DISORDER IN 68.2% of cases. This is in accordance with epidemiological findings that these two types of morbidity have a positive association and coexist in 20-50% of patients. Depression was the commonest psychiatric disorder in all classes of organic disease and accounted for 53% of all psychiatric diagnoses. Organic brain syndromes, acute and chronic constituted 18% of referrals. Almost twice as many women as men were referred despite their nearly equal distribution in hospital population. One-third of the females had no positive medical diagnosis compared to one-fifth of the men. Alcoholism was a major problem in 8.9% of referrals. 7.8% of patients were referred following suicidal attempt. Of the 50 patients with cancer. 66% had depression. Too few medical patients with psychiatric complications are referred and adequately treated. Greater emphasis on teaching psychiatric syndromes is called for. Psychiatric consultation-liaison services offer the most direct form of collaboration between psychiatry and medicine in the interests of comprehensive patient care.
TL;DR: The cellular actions of VP are divided into two major sequential biochemical events: the interaction of the hormone with its receptor and the effect of this reaction on cyclic AMP metabolism and the reactions by which cyclicAMP, in turn, may elicit changes in water permeability.
TL;DR: The complementary cognitive specialisation of the two cerebral hemispheres has led to speculation about its significance for understanding individual differences in cognitive style as discussed by the authors, and it has been suggested that some people rely primarily on the left hemisphere whereas others rely on the right.
Abstract: THE discovery of complementary cognitive specialisation of the two cerebral hemispheres has led to speculation about its significance for understanding individual differences in cognitive style. It has been suggested1,2 that some people rely primarily on the left hemisphere whereas others rely on the right, and that this may be an important determinant of a person's cognition of his world.
TL;DR: Results are consistent with a protonmotive Q cycle mechanism in which the oxidation factor catalyzes electron transfer from reduced quinone to cytochrome c 1 and thus liberates from reducedQuinone one of two protons required for energy conservation during electron transfer through the cy tochrome b - c 1 complex.
TL;DR: This paper provides a fairly complete list of information and distance measures including a new average conditional cubic entropy proposed by the author and major problem areas such as computation with these measures are examined and methods of approach for the unresolved problems are suggested.
TL;DR: Exposure of pregnant hamsters on gestation day 8 to 40 or 41 degrees C for one hour caused an increased rate of resorption and a high frequency of exencephaly and encephalocele.
Abstract: Exposure of pregnant hamsters on gestation day 8 to 40 or 41 degrees C for one hour caused an increased rate of resorption and a high frequency of exencephaly and encephalocele. Longer exposures often killed pregnant females. Hamsters that had fetuses with abnormalities usually experienced body temperature elevations of 3-4 degrees C above normal (37 degrees C).
TL;DR: The data show that unreinforced stimulus presentations can produce both relatively permanent response decrements and apparently independent short-term decrements, and suggest that long-term retention may be more generally characteristic of habituation than is usually assumed.
Abstract: Response decrement produced by a single, 2-sec, 98 dB, auditory stimulus in rats was retained without detectable loss for intervals ranging from approximately 30 sec to 30 days. Response decrements produced by stimulation over these intervals reached an apparent asymptote after 2 or 3 stimulus presentations. These response decrements were unambiguously associated with stimulus presentation for the lick suppression measure, but nonspecific decremental effects may have contributed to the startle response decrements. After these long-term decrements had reached asymptote, 300 stimulus presentations with 1-sec interstimulus intervals produced further response decrements, but these decrements recovered completely within 24 hr., responsiveness returning to the previously established long-term asymptote. The data show that unreinforced stimulus presentations can produce both relatively permanent response decrements and apparently independent short-term decrements. The data also suggest that long-term retention may be more generally characteristic of habituation than is usually assumed.
Journal Article•
TL;DR: It is established that enzymatic protoporphyrinogen oxidation can occur in the absence of molecular oxygen, in contrast to previous observations using mammalian and yeast mitochondria.
01 Jan 1976
TL;DR: A brief overview of the structure of the magnetopause and the adjoining plasma boundary layer is given in this paper, where the relationship between these electromagnetic and plasma structures on the front lobe of magnetosphere and the magnetic field reconnection process is discussed.
Abstract: A brief overview is given of our present knowledge, observational and theoretical, of the structure of the magnetopause and the adjoining plasma boundary layer. Particular attention is given to the relationship between these electromagnetic and plasma structures on the front lobe of the magnetosphere and the magnetic field reconnection process. Items discussed include: magnetopause thickness; behavior of magnetic field components parallel and perpendicular to the magnetopause; particle energization; structure of the boundary layer from reconnection theory.
TL;DR: The results suggest that SWS resets a central mechanism influencing termination of inspiration and that this action is offset or eliminated during REMS, and the constancy of diaphragmatic activation and end-tidal P CO 2 suggests that other features of respiratory control are not greatly altered during sleep.
TL;DR: It is shown that marine dinoflagellates under natural conditions synthesize the unusual fatty acid octapentadecaenoic (18∶5ω3), which is very likely a characteristic of certain groups of phytoplankters and is not an artifact from artificial culture conditions.
Abstract: It is shown that marine dinoflagellates under natural conditions synthesize the unusual fatty acid octapentadecaenoic (18∶5ω3). This acid is very likely a characteristic of certain groups of phytoplankters and is not an artifact from artificial culture conditions. Various species of herbivorous copepods as well as contemporary carnivorous chaetognaths living in the same environment present traces of this fatty acid. The decreasing quantity of 18∶5ω3 on moving up the food chain, and its absence in certain species, makes it a possible ecological tracer.
TL;DR: Using cortisol and dexamethasone, the kinetic behavior of glucocorticoid receptors in intact rat thymus cells at 37°C is studied to suggest formation of nuclear complex by direct reaction of hormone with nuclear-bound receptors.
TL;DR: In this article, the results of a VLF (0.3-18 kHz) experiment aboard OGO 4 are compared with simultaneous data obtained by the satellite on precipitating electrons at 0.7, 2.3, and 7.3 keV to determine the source of the auroral hiss band in the night side auroral zone.
Abstract: The results of a VLF (0.3-18 kHz) experiment aboard OGO 4 are compared with simultaneous data obtained by the satellite on precipitating electrons at 0.7, 2.3, and 7.3 keV to determine the source of the auroral hiss band in the night side auroral zone. At these energies the correlation with VLF auroral hiss is best at 0.7 keV and worst at 7.3 keV. Auroral electrons in the keV range may enhance the intensity of VLF auroral hiss on the night side, but the predominant source of night side hiss appears to be electrons of energies below 0.7 keV. Auroral hiss tends to occur simultaneously over a broad range of frequencies. A study based on OGO 6 data has revealed a lack of correlation between keV electrons and LF auroral hiss. These observations suggest that hiss of all frequencies is generated by electrons with energies below about 1 keV. The excellent correlation between auroral hiss and 0.7 keV electrons in the day time cleft is apparently maintained when the region of very soft electron precipitation is in motion.