Showing papers by "Harvard University published in 1975"
Book•
01 Jan 1975TL;DR: Ressenya de l'obra d'E. O. Wilson apareguda el 1975, Sociobiology. The New Synthesis.The Belknap Press of Harvard University Press.
Abstract: Ressenya de l'obra d'E. O. Wilson apareguda el 1975, Sociobiology. The New Synthesis .The Belknap Press of Harvard University Press.
6,126 citations
Book•
01 Jan 1975TL;DR: The Relaxation Response has become the classic reference recommended by most health care professionals and authorities to treat the harmful effects of stress.
Abstract: When Dr. Herbert Benson introduced this simple, effective, mind/body approach to relieving stress twenty-five years ag, his book became an instant national bestseller. Since that time, millions of people have learned the secret--without high-priced lectures or prescription medicines. The Relaxation Response has become the classic reference recommended by most health care professionals and authorities to treat the harmful effects of stress.Discovered by Dr. Benson and his colleagues in the laboratories of Harvard Medical School and its teaching hospitals, this revitalizing, therapeutic approach is now routinely recommended to treat patients suffering from heart conditions, high blood pressure, chronic pain, insomnia, and many other physical ailments. It requires only minutes to learn, and just ten to twenty minutes of practice twice a day.
2,613 citations
TL;DR: This work has shown that impulsiveness seems to be best accounted for by the hyberbolic curves that have been found to describe the decline in effectiveness of rewards as the rewards are delayed from the time of choice.
Abstract: In a choice among assured, familiar outcomes of behavior, impulsiveness is the choice of less rewarding over more rewarding alternatives. Discussions of impulsiveness in the literature of economics, sociology, social psychology, dynamic psychology and psychiatry, behavioral psychology, and \"behavior therapy\" are reviewed. 'Impulsiveness seems to be best accounted for by the hyberbolic curves that have been found to describe the decline in effectiveness of rewards as the rewards are delayed from the time of choice. Such curves predict a reliable change of choice between some alternative rewards as a function of time. This change of choice provides a rationale for the known kinds of impulse control and relates them to several hitherto perplexing phenomena: behavioral rigidity, time-out from positive reinforcement, willpower, self-reward, compulsive traits, projection, boredom, and the capacity of punishing stimuli to attract attention.
2,550 citations
TL;DR: In this article, a load network is synthesized to have a transient response which maximizes power efficiency even if the active device switching times are substantial fractions of the a.c. cycle.
Abstract: The new class of amplifiers described is based on a load network synthesized to have a transient response which maximizes power efficiency even if the active device switching times are substantial fractions of the a.c. cycle. The new class of amplifiers, named `Class E,' is defined and is illustrated by a detailed description and a set of design equations for one simple member of the class. For that circuit the authors measured 96 percent transistor efficiency at 3.9 MHz at 26-W output from a pair of Motorola 2N3735 TO-5 transistors. Advantages of Class E are unusually high efficiency, a priori designability, large reduction in second-breakdown stress, low sensitivity to active-device characteristics, and potential for high-efficiency operation at higher frequencies than previously published Class-D circuits.
1,902 citations
TL;DR: The development of the sequence of spatial representations in children conforms to the “main sequence” identified in the construction of spatial representation in adults, as a potential explanation for the extensive parallelisms identified among ontogenesis, microgenesis, the course of pathology, and the recovery of function following pathological insult.
Abstract: Publisher Summary A series of neurological and philosophical discussions has led to suggestions that space is a model of the environment, constructed from the temporal integration of successive perceptions, which model man as neurologically disposed to create and organize. The model is coordinated to social conventions. It develops and is vulnerable to dissolution. Studies of adults' knowledge about their macroenvironment suggest that human “maps” are not literally maps. Rather, they tend to be fragmented, distorted projectively, and are often several multiple “mini-spatial-representations.” Landmarks and routes are the minimal elements of spatial representation. Survey-representations incorporate configurational elements (outlines, graphic skeletons, figurative metaphors) and may be the final derivative of dense, richly interconnected, and hierarchically organized route maps. The notion of “main sequences” was introduced as a potential explanation for the extensive parallelisms identified among ontogenesis, microgenesis, the course of pathology, and the recovery of function following pathological insult. The development of the sequence of spatial representations in children conforms to the “main sequence” identified in the construction of spatial representation in adults.
1,757 citations
TL;DR: A rapid method for the flow microfluorometric determination of the DNA content per cell is described, which requires a minimal amount of material, and avoids formation of cell clumps.
Abstract: A rapid method for the flow microfluorometric determination of the DNA content per cell is described. Incubation of cells in a hypotonic solution of propidium iodide results in disruption of the cell membrane and rapid staining of nuclear chromatin. DNA distribution histograms generated from cells stained by this method are identical to those generated after fixation and RNase digestion. In contrast to some earlier described methods, the present technique is rapid (5 min of processing), requires a minimal amount of material, and avoids formation of cell clumps.
1,751 citations
TL;DR: The sine-Gordon soliton was identified with the fundamental fermion of the Thirring model in this paper, where it was shown that the energy density of the theory is unbounded below.
Abstract: The sine-Gordon equation is the theory of a massless scalar field in one space and one time dimension with interaction density proportional to $cos\ensuremath{\beta}\ensuremath{\phi}$, where $\ensuremath{\beta}$ is a real parameter. I show that if ${\ensuremath{\beta}}^{2}$ exceeds $8\ensuremath{\pi}$, the energy density of the theory is unbounded below; if ${\ensuremath{\beta}}^{2}$ equals $4\ensuremath{\pi}$, the theory is equivalent to the zero-charge sector of the theory of a free massive Fermi field; for other values of $\ensuremath{\beta}$, the theory is equivalent to the zero-charge sector of the massive Thirring model. The sine-Gordon soliton is identified with the fundamental fermion of the Thirring model.
1,438 citations
1,246 citations
TL;DR: During the sleep cycle in cats, neurons localized to the posterolateral pole of the nucleus locus coeruleus and the nucleus subcoeruleus undergo discharge rate changes that are the opposite of those of the pontine reticular giant cells.
Abstract: During the sleep cycle in cats, neurons localized to the posterolateral pole of the nucleus locus coeruleus and the nucleus subcoeruleus undergo discharge rate changes that are the opposite of those of the pontine reticular giant cells. The inverse rate ratios and activity curves of these two interconnected populations are compatible with reciprocal interaction as a physiological basis of sleep cycle oscillation.
TL;DR: In this paper, the authors explore the implications for hadron spectroscopy of the "standard" gauge model of weak, electromagnetic, and strong interactions, and use the asymptotic freedom of the model to argue that for the calculation of hadron masses, the short-range quark-quark interaction may be Coulomblike.
Abstract: We explore the implications for hadron spectroscopy of the "standard" gauge model of weak, electromagnetic, and strong interactions. The model involves four types of fractionally charged quarks, each in three colors, coupling to massless gauge gluons. The quarks are confined within colorless hadrons by a long-range spin-independent force realizing infrared slavery. We use the asymptotic freedom of the model to argue that for the calculation of hadron masses, the short-range quark-quark interaction may be taken to be Coulomb-like. We rederive many successful quark-model mass relations for the low-lying hadrons. Because a specific interaction and symmetry-breaking mechanism are forced on us by the underlying renormalizable gauge field theory, we also obtain new mass relations. They are well satisfied. We develop a qualitative understanding of many features of the hadron mass spectrum, such as the origin and sign of the $\ensuremath{\Sigma}\ensuremath{-}\ensuremath{\Lambda}$ mass splitting. Interpreting the newly discovered narrow boson resonances as states of charmonium, we use the model to predict the masses of charmed mesons and baryons.
TL;DR: In this paper, an intrinsic and complete description of electromagnetism in a space-time region is formulated in terms of a nonintegrable phase factor, and connections on principal fiber bundles are identified.
Abstract: Through an examination of the Bohm-Aharonov experiment an intrinsic and complete description of electromagnetism in a space-time region is formulated in terms of a nonintegrable phase factor. This concept, in its global ramifications, is studied through an examination of Dirac's magnetic monopole field. Generalizations to non-Abelian groups are carried out, and result in identification with the mathematical concept of connections on principal fiber bundles.
TL;DR: In this paper, it is shown in the context of a simple model of gauge mesons coupled to massive fermions that the heavy fields decouple at low momenta except for their contribution to renormalization effects.
Abstract: We examine some problems associated with the low-momentum behavior of gauge theories and other renormalizable field theories. Our main interest is in the infrared structure of unbroken non-Abelian gauge theories and how this is affected by the presence of other heavy fields coupled to the massless gauge fields. It is shown in the context of a simple model of gauge mesons coupled to massive fermions that the heavy fields decouple at low momenta except for their contribution to renormalization effects. This result is used to discuss the mass-shell structure of the fermion propagator. The decoupling theorem is then stated for a general renormalizable theory and applied to some interesting examples. One is a more general gauge theory which makes use of the Higgs mechanism and attempts to unify the elementary particle forces. Another is the connection of the linear and nonlinear $\ensuremath{\sigma}$ models in the limit ${m}_{\ensuremath{\sigma}}\ensuremath{\rightarrow}\ensuremath{\infty}$.
TL;DR: Principals of statistical decision theory and information theory suggest technics for objectively determining these cutoff points, depending upon whether the physician is concerned with health costs, with financial costs, or with the information content of the test.
Abstract: The value of a diagnostic test lies in its ability to detect patients with disease (its sensitivity) and to exclude patients without disease (its specificity). For tests with binary outcomes, these measures are fixed. For tests with a continuous scale of values, various cutoff points can be selected to adjust the sensitivity and specificity of the test to conform with the physician's goals. Principles of statistical decision theory and information theory suggest technics for objectively determining these cutoff points, depending upon whether the physician is concerned with health costs, with financial costs, or with the information content of the test.
TL;DR: Results indicate that the host-versus-graft reaction alone can enihance murine cvtomtiegalovirus in a chronicallY injected host atid maY help explain the high incidence of cvvtomegalov virus infection seen after renal and other allograft transplantation.
Abstract: C3H/He mice chronically infected with murine cYtomegalo virus were given skin allografis fromti histoincompatible BALB/c donors. A significant inicrease in cvtomegalovirus titers occurred within 3 days after placement oJ'the graft in the spleens and kidneYs oJ' the allograft recipients as compared with control aninmals. No significant changes in virus titers were detected in the salivary gland, lung, liver, or blood ofallograJi recipients. These results indicate that the host-versus-graft reaction alone can enihance murine cvtomtiegalovirus in a chronicallY injected host atid maY help explaini the high incidence ofcvvtomegalovirus infection seen after renal and other allograft transplantation
TL;DR: In this paper, the elastic-gravitational free oscillations of the Earth are used to derive procedures for resolving nearly degenerate multiplets of normal modes of an earthquake point source.
Abstract: A cyclic process of refining models of the mechanical structure of the Earth and models of the mechanism of one or more earthquakes is developed. The theory of the elastic-gravitational free oscillations of the Earth is used to derive procedures for resolving nearly degenerate multiplets of normal modes. We show that a global network of seismographs (W.W.S.S.N.) permits resolution for angular orders l ≤ 76 and for frequencies a) w ≤ 0.090 s -1 . The peak or centre frequency of each nearly degenerate multiplet is interpreted to be a gross Earth datum. Together, the data are used to refine models of the mechanical structure of the Earth. The theory of free oscillations is used further to derive procedures for retrieving the mechanism, or moment tensor, of an earthquake point source. We show that a globa network of seismographs permits retrieval for frequencies 0.0125 s-1 ≤ w ≤ 0.0825 s-1 . We show that refined models of structure and mechanism lead to improved resolution and retrieval, and that an array of sources further complements the resolution of multiplets. We present a ‘standardized dataset’ of 1064 distinct, observed eigenfrequencies ol the elastic-gravitational free oscillations of the Earth. These gross-Earth data are compiled from 1461 modes reported in five studies: 2 modes reported by Derr (1969), 159 modes observed by Brune & Gilbert (1974), 240 modes observed by Mendiguren ( 1973), 248 modes observed by Dziewonski & Gilbert (1972,1973) and 812 modes reported here. It is our opinion that the establishment of a standardized dataset should precede the establishment of a standardized model of the Earth. Two new Earth models are presented that are compatible with the modal data. One is derived from model 508 (Gilbert & Dziewonski 1973) and the other from model B1 (Jordan & Anderson 1974). In the outer core and in the lower mantle, below a depth of about 950 km, the differences between the two models are negligibly small. In the inner core there are minor differences and in the upper mantle there are major differences in detail. The two models and the modal data are compatible with traditional ray data, provided that appropriate baseline corrections are made to the latter. The source mechanisms, or moment tensors, of two deep earthquakes, Colombia (1970 July 31) and Peru-Bolivia (1963 August 15), have been retrieved from the seismic spectra. In both cases the moment tensor possesses a compressive (implosive) isotropic part. There is good evidence that isotropic stress release begins gradually, over 80s before the origin time derived from the onset of short-period P and S waves. During the process of stress release the principal axes of the moment rate tensor migrate. The axis of compression is relatively stable, the compressive stress rate is dominant, and the other two axes rotate about the axis of compression. We speculate that earthquakes, occurring deep within descending lithospheric plates, are not sudden shearing movements alone but do exhibit compressive changes in volume such as would be associated with a phase change. We further speculate that compressive changes in volume may occur without sudden shearing movements, that there may be 9 silent earthquakes’.
TL;DR: In this paper, the De Rham Complex of a Compact K~ihler Manifold has been shown to be a homotopy theory of differential algebras.
Abstract: 1. Homotopy Theory of Differential Algebras . . . . . . . . . . 248 2. De Rham Homotopy Theory . . . . . . . . . . . . . . . 254 3. Relation between De Rham Homotopy Theory and Classical Homotopy Theory . . . . . . . . . . . . . . . . . . . . . . . . 256 4. Formality of Differential Algebras . . . . . . . . . . . . . . 260 5. The De Rham Complex of a Compact K~ihler Manifold . . . . . 262 6. The Main Theorem and Two Proofs . . . . . . . . . . . . . 270 7. An Application . . . . . . . . . . . . . . . . . . . . . . 272
TL;DR: This paper found that people who believe in a just world are more likely than nonbelievers to admire fortunate people and to derogate victims, thus permitting the believers to maintain the perception that people in fact get what they deserve.
Abstract: Research with the Just World Scale has indicated that many people believe that the world is a place where good people are rewarded and bad people are punished. Believers in a just world have been found to be more likely than nonbelievers to admire fortunate people and to derogate victims, thus permitting the believers to maintain the perception that people in fact get what they deserve. Other studies have shed light on the antecedents, correlates, and social consequences of the belief in a just world. Everyone may have a version of the just world belief in early childhood (Piaget's “immanent justice”), but some people outgrow the belief quickly and some apparently never do. Believers in a just world have been found to be more religious, more authoritarian, and more oriented toward the internal control of reinforcements than nonbelievers. They are also more likely to admire political leaders and existing social institutions, and to have negative attitudes toward underprivileged groups. Suggestions for modifying the belief in a just world are offered, focusing on the socialization techniques employed by parents, teachers, religious institutions, and the mass media.
TL;DR: This medium has proved successful in maintaining the growth characteristics of both phases of Candida albicans during serial transfers and the relative pathogenicity, virulence, invasiveness and immunogenicity of the yeast and mycelial phases are discussed.
Abstract: A chemically defined medium composed of 6 amino acids, biotin, inorganic salts and glucose for the growth of yeast and mycelial phases of Candida albicans at 25 degrees C and 37 degrees of C respectively was developed based on the aminopeptidase(s) profile of the fungus. This medium has proved successful in maintaining the growth characteristics of both phases during serial transfers. The relative pathogenicity, virulence, invasiveness and immunogenicity of the yeast and mycelial phases are discussed.
TL;DR: Much of what I will discuss here today relates to brain differentiation in rodents, which was the interest of two outstanding British scientists, Geoffrey Harris and Peter MacDonald.
Abstract: Much of what I will discuss here today relates to brain differentiation in rodents. This subject was the interest of two outstanding British scientists, Geoffrey Harris and Peter MacDonald. Harris spent his scientific life and considerable intellectual powers observing and enlarging upon this very interesting phenomenon, which was originally described so brilliantly by Carroll Pfeiffer in 1936. Peter MacDonald was an outstanding young man who had already shown the key role of estrogens in central steroid actions by experiments such as the use of antiestrogens to block the action of androgens on brain differentiation, as described below. Geoffrey Harris’ life ended at the pinnacle and fruition of a career that included the elucidation of the neurovascular and chemical links between the brain and pituitary and the isolation of the LH releasing factor. Peter MacDonald's life and continued work were prematurely lost in the recent Paris air disaster; we can only guess what he might have contributed in years to come. However, both of these men left important scientific and intellectual legacies, part of which you have already heard about. If a man's work is what others judge him by, these two will stand up well to any test, any time. We owe them our gratitude and continued remembrance.
TL;DR: The complete structure of the anterior sensory nervous system of the small nematode C. elegans has been determined by reconstruction from serial section electronmicrographs and is found to be largely invariant.
Abstract: The complete structure of the anterior sensory nervous system of the small nematode C. elegans has been determined by reconstruction from serial section electronmicrographs. There are 58 neurons in the tip of the head. Fifty-two of these are arranged in sensilla. These include six inner labial sensilla, six outer labial sensilla, four cephalic sensilla and two amphids. Each sensillum consists of ciliated sensory neurons ending in a channel enclosed by two non-neuronal cells, the sheath and socket cells. The amphidial channel opens to the outside as does that of the inner labial sensilla so that these probably contain chemoreceptive neurons. The endings of the other sensilla are embedded in the cuticle and may be mechanoreceptive. The cell bodies of all the neurons lie near the nerve ring and their axons project into the ring or into ventral ganglia. One of the ciliated sensory neurons in each of the six inner labial sensilla makes direct chemical synapses onto a muscle making these sensory-motor neurons. The anatomy of four isogenic animals was compared in detail and found to be largely invariant. The anatomy of juveniles is nearly identical to that of the adult, but males have four additional neuron processes.
TL;DR: The CONCOR procedure is applied to several illustrative sets of social network data and is found to give results that are highly compatible with analyses and interpretations of the same data using the blockmodel approach of White.
TL;DR: It is concluded that large amounts of genetic variation can be maintained by mutation in polygenic characters even when there is strong stabilizing selection.
Abstract: It is assumed that a character under stabilizing selection is determined genetically by n linked, mutable loci with additive effects and a range of many possible allelic effects at each locus. A general qualitative feature of such systems is that the genetic variance for the character is independent of the linkage map of the loci, provided linkage is not very tight. A particular detailed model shows that certain aspects of the genetic system are moulded by stabilizing selection while others are selectively neutral. With reference to experimental data on characters of Drosophila flies, maize, and mice, it is concluded that large amounts of genetic variation can be maintained by mutation in polygenic characters even when there is strong stabilizing selection. The properties of the model are compared with those of heterotic models with linked loci.
TL;DR: The projection of cells in different layers of several cortical visual areas in the cat were studied using the method of retrograde transport of horseradish peroxidase, indicating a remarkable specificity in the projections of the cortical layers.
Abstract: The projection of cells in different layers of several cortical visual areas in the cat were studied using the method of retrograde transport of horseradish peroxidase. Injections of the enzyme were made through a recording micropipette, making it possible to localize the injection site by physiological criteria. We found that layer VI cells projected to the alteral geniculate nucleus, while a distinct population of cells in layer V projected to the superior colliculus. Cells in layers II and III were tha major sources of ipsilateral cortico-cortical connections. This pattern of projection was consistent from one visual area to another. Pyramidal cells appeared to be the source of cortico-geniculate, cortico-collicular and cortico-cortical projections. The proportion of cells within a layer that terminated in a given site varied from layer to layer: apparently all of the large pyramids in layer V had terminals in the superior colliculus, about half of the pyramids in layer VI had terminals in the lateral geniculate nucleus, while only a small proportion of the pyramids in layers II and III had terminals in any single cortical area. The results indicated a remarkable specificity in the projections of the cortical layers. The cortical connections of the different cell types in layers A and A1 of the lateral geniculate nucleus were also examined: the cells that projected to area 17 were much more numerous and were on the average smaller than those that projected to area 18. Projections to the cortex were also found from the pulvinar, the medial interlaminar nucleus and the posterior nucleus. Direct connections were observed to the lateral geniculate nucleus from several midbrain reticular nuclei. Finally, projections were found to the superior colliculus from the zona incerta, the reticular nucleus of the thalamus and the ventral lateral geniculate nucleus.
TL;DR: Cross-lagged panel correlation as mentioned in this paper is a method for testing spuriousness by comparing crosslagged correlations, which is based on a set of assumptions: synchronicity and stationarity.
Abstract: Cross-lagged panel correlation is a method for testing spuriousness by comparing cross-lagged correlations. True experiments control for spuriousness by random assignment, but random assignment limits true experimental studies to independent variables that can be manipulated. Like any statistical method, cross-lagged analysis is based on a set of assumptions: synchronicity and stationarity. Different forms of stationarity have different consequences for both the changes in the synchronous correlations over time and the difference between cross-lags. Homogeneous stability is a necessary assumption in the identification of both the source and direction of a causal effect. Cross-lagged analysis is a low-power test. It is better adapted than either multiple regression or factor analysis for many questions in panel studies. Multiple regression must assume no errors of measurement in the independent variables and no correlated errors, while factor analysis must specify a particular factor structure. Two extended examples of cross-lagged analysis are discussed with special emphasis placed on the issue of stationarity and the estimation of reliability ratios.
TL;DR: The caudal levels of the orbitofrontal area were found to give rise to an additional projection which terminated in the entorhinal cortex and the transitional cortices bordering the rhinal sulcus, providing a much more direct means for the frontal lobe to influence the hippocampus than those involving the cingulate gyrus.
TL;DR: In this article, a basic tensile bifurcation problem is studied for an incompressible rectangular block constrained to undergo plane deformations, where the sides of the block are traction-free and it is elongated by a uniform, shear-free, relative displacement of its ends.
Abstract: A basic tensile bifurcation problem is studied. Bifurcations from a state of homogeneous inplane tension are investigated for an incompressible rectangular block constrained to undergo plane deformations. The sides of the block are traction-free, and it is elongated by a uniform, shearfree, relative displacement of its ends. For a wide class of incrementally-linear, time-independent materials only two instantaneous moduli enter into the analysis. Symmetric and anti-symmetric bifurcations are examined in each of the characteristic regimes of the governing equations (elliptic, parabolic and hyperbolic). Both diffuse modes and localized shearing modes are considered. Lowest bifurcation stresses are computed for essentially the entire range of possible combinations of material properties and geometry. A number of limiting cases are studied in detail, including those for slender and stubby specimens and for specimens which are rigid in shear. Applications to elastic and elastic/plastic solids are discussed.