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Showing papers by "Harvard University published in 1979"


Journal ArticleDOI
TL;DR: Quantitative procedures for computing the tolerance for filed and future null results are reported and illustrated, and the implications are discussed.
Abstract: For any given research area, one cannot tell how many studies have been conducted but never reported. The extreme view of the "file drawer problem" is that journals are filled with the 5% of the studies that show Type I errors, while the file drawers are filled with the 95% of the studies that show nonsignificant results. Quantitative procedures for computing the tolerance for filed and future null results are reported and illustrated, and the implications are discussed. (15 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)

7,159 citations


Journal ArticleDOI
TL;DR: In this paper, the authors criticise the adaptationist program for its inability to distinguish current utility from reasons for origin (male tyrannosaurs may have used their diminutive front legs to titillate female partners, but this will not explain why they got so small).
Abstract: An adaptationist programme has dominated evolutionary thought in England and the United States during the past 40 years. It is based on faith in the power of natural selection as an optimizing agent. It proceeds by breaking an organism into unitary 'traits' and proposing an adaptive story for each considered separately. Trade-offs among competing selective demands exert the onlv brake upon perfection; non-optimality is thereby rendered as a result of adaptation as well. We criticize this approach and attempt to reassert a competing notion (long popular in continental Europe) that organisms must be analysed as integrated wholes, with Bauplane so constrained by phyletic heritage, pathways of development and general architecture that the constraints themselves become more interesting and more important in delimiting pathways of change than the selective force that may mediate change when it occurs. We fault the adaptationist programme for its failure to distinguish current utility from reasons for origin (male tyrannosaurs may have used their diminutive front legs to titillate female partners, but this will not explain why they got so small); for its unwillingness to consider alternatives to adaptive stories; for its reliance upon plausibility alone as a criterion for accepting speculative tales; and for its failure to consider adequately such competing themes as random fixation of alleles, production of nonadaptive structures by developmental correlation with selected features (allometry, pleiotropy, material compensation, mechanically forced correlation), the separability of adaptation and selection, multiple adaptive peaks, and current utility as an epiphenomenon of non-adaptive structures. We support Darwin's own pluralistic approach to identifying the agents of evolutionary change.

5,853 citations


Posted Content
TL;DR: In this paper, the joint maximum likelihood estimator of the structural parameters is not consistent as the number of groups increases, with a fixed number of observations per group, and a conditional likelihood function is maximized, conditional on sufficient statistics for the incidental parameters.
Abstract: In data with a group structure, incidental parameters are included to control for missing variables. Applications include longitudinal data and sibling data. In general, the joint maximum likelihood estimator of the structural parameters is not consistent as the number of groups increases, with a fixed number of observations per group. Instead a conditional likelihood function is maximized, conditional on sufficient statistics for the incidental parameters. In the logit case, a standard conditional logit program can be used. Another solution is a random effects model, in which the distribution of the incidental parameters may depend upon the exogenous variables.

2,338 citations


Journal ArticleDOI
TL;DR: The new National Center for Health Statistics percentiles can be used to improve identification of potential health and nutritional problems and to facilitate the epidemological comparison of one group of children with others.

2,327 citations


Journal ArticleDOI
Edward Witten1
TL;DR: In this article, the existing results concerning mesons and glue states in the large-N limit of QCD are reviewed, and it is shown how to fit baryons into this picture.

1,934 citations


Journal ArticleDOI
TL;DR: In this article, the problem of decomposing this space of functions into irreducible representations of a finite Chevalley group G(Fq) is equivalent to decomposing the regular representation o f ~ | | (12) of a Coxeter group.
Abstract: here l(w) is the length of w In the case where Wis a Weyl group and q is specialized to a fixed prime power, | ~ can be interpreted as the algebra of intertwining operators of the space of functions on the flag manifold of the corresponding finite Chevalley group G(Fq) (see [loc cit, Ex 24]) Therefore, the problem of decomposing this space of functions into irreducible representations of G(Fq) is equivalent to the problem of decomposing the regular representation o f ~ | (12 It is known that, in this case, | is isomorphic to the group algebra of W; however, in general, this isomorphism cannot be defined without introducing a square root of q (see [1]) It is therefore, natural to extend the ground ring of ~ as follows For any Coxeter group (W, S) we define the Hecke algebra ~ to be J{' | A, where A is the ring of Laurent polynomials with integral coefficients in the indeterminate ql/2 Our purpose is to construct representations oL,Uf endowed with a special basis They will be defined in terms of certain graphs We define a W-graph to be a set of vertices X, with a set Y of edges (an edge is a subset of X consisting of two elements) together with two additional data: for each vertex xeX , we are given a subset I x of S and, for each ordered pair of vertices y, x such that {y, x} e Y, we are given an integer p(y, x) +0 These data are subject to the requirements (10a), (10b) below Let E be

1,865 citations


Journal ArticleDOI
TL;DR: In this paper, a number of properties of possible baryon and lepton-nonconserving processes are shown under very general assumptions, and the importance of measuring the polarizations and ratios in nucleon decay as a means of discriminating among specific models is discussed.
Abstract: A number of properties of possible baryon- and lepton-nonconserving processes are shown to follow under very general assumptions. Attention is drawn to the importance of measuring ${\ensuremath{\mu}}^{+}$ polarizations and $\frac{{\overline{\ensuremath{ u}}}_{e}}{{e}^{+}}$ ratios in nucleon decay as a means of discriminating among specific models.

1,746 citations


Journal ArticleDOI
TL;DR: In this paper, a theory of dislocation-mediated melting in two dimensions is described in detail, with an emphasis on results for triangular lattices on both smooth and periodic substrates, and the behavior of the specific heat, structure factor, and various elastic constants near these transitions is worked out.
Abstract: A theory of dislocation-mediated melting in two dimensions is described in detail, with an emphasis on results for triangular lattices on both smooth and periodic substrates. The transition from solid to liquid on a smooth substrate takes place in two steps with increasing temperatures. Dissociation of dislocation pairs first drives a transition out of a low-temperature solid phase, with algebraic decay of translational order and long-range orientational order. This transition is into a "liquid-crystal" phase characterized by exponential decay of translational order, but power-law decay of sixfold orientational order. Dissociation of disclination pairs at a higher temperature then produces an isotropic fluid. The behavior of the specific heat, structure factor, and various elastic constants near these transitions is worked out. We also discuss the applicability of our results to melting on a periodic substrate. Dislocation unbinding should describe melting of a "floating" (and, in general, incommensurate) adsorbate solid into a high-temperature fluid phase. The orientation bias imposed by the substrate can alter or eliminate the disclination-unbinding transition, however. Transitions from a floating solid into a low-temperature registered or partially registered phase can also be mapped onto the dislocation-unbinding transition, but only at certain special values of the coverage. Substrate reciprocallattice vectors play the role of Burger's vectors in this case.

1,476 citations


Book
01 Oct 1979

1,421 citations


Journal ArticleDOI
19 Oct 1979-Science
TL;DR: Three novel nonoclonal antibodies (designed OKT1, OKT3, and OKT4) were generated against surface determinants of human peripheral T cells but differed in their reactivities with T cel- lines.
Abstract: Three novel nonoclonal antibodies (designed OKT1, OKT3, and OKT4) were generated against surface determinants of human peripheral T cells. Both OKT1 and OKT3 reacted with all human peripheral T cells and 5 to 10 percent of thymocytes but differed in their reactivities with T cel- lines. By contrast, OKT4 reacted with 55 percent of human peripheral T cells and 80 percent of thymocyted in that they did not react with normal B cells, null cells, monocytes, or granulocytes.

1,385 citations


Journal ArticleDOI
TL;DR: A dot hybridization method is presented for rapidly determining the relative concentrations of nucleic acids in a mixture, as well as the extent of sequence homology between related RNA or DNA species.
Abstract: A dot hybridization method is presented for rapidly determining the relative concentrations of nucleic acids in a mixture, as well as the extent of sequence homology between related RNA or DNA species.

Journal ArticleDOI
Edward Witten1
TL;DR: In this paper, the U(1) problem is reconsidered from the point of view of the 1 N expansion, and it is argued that various heuristic ideas about the η′ are valid from this view.

Journal ArticleDOI
16 Nov 1979-JAMA
TL;DR: It is concluded that ECMO can support respiratory gas exchange but did not increase the probability of long-term survival in patients with severe ARF.
Abstract: Nine medical centers collaborated in a prospective randomized study to evaluate prolonged extracorporeal membrane oxygenation (ECMO) as a therapy for severe acute respiratory failure (ARF). Ninety adult patients were selected by common criteria of arterial hypoxemia and treated with either conventional mechanical ventilation (48 patients) or mechanical ventilation supplemented with partial venoarterial bypass (42 patients). Four patients in each group survived. The majority of patients suffered acute bacterial or viral pneumonia (57%). All nine patients with pulmonary embolism and six patients with posttraumatic acute respiratory failure died. The majority of patients died of progressive reduction of transpulmonary gas exchange and decreased compliance due to diffuse pulmonary inflammation, necrosis, and fibrosis. We conclude that ECMO can support respiratory gas exchange but did not increase the probability of long-term survival in patients with severe ARF. (JAMA242:2193-2196, 1979)

Journal ArticleDOI
TL;DR: It is hypothesized that the threat posed by infanticide is one of several pressures selecting for a shift among higher primates away from strictly cyclical estrous receptivity towards socially determined or situation-dependent receptivity.

Journal ArticleDOI
TL;DR: M1/70 thus defines a differentiation antigen on mononuclear phagocytes and granulocytes, the expression of which is specifically increased during monocyte maturation, the first to be described which recognizes a discrete molecule specific to phagocyte.
Abstract: We have previously described the derivation of M1/70, a hybrid myeloma line secreting monoclonal rat anti-mouse cell surface antibody (Springer, T., Galfre, G., Secher, D. S. and Milstein, C, Eur. J. Immunol. 1978. 8: 539). We have now investigated the cellular distribution of this antigen using a 125I-labeled anti-rat IgG indirect binding assay, the fluorescence-activated cell sorter, autoradiography and precipitation of cell surface molecules. Screening with a tumor cell panel showed strong reactivity with a macrophage-like line but no reactivity with B or T lymphoma lines. In normal tissues, M1/70 antigen was found to be present in small amounts on spleen and exudate granulocytes and a subpopulation of bone marrow cells, in moderate amounts on spleen and blood monocytes and expressed in much larger amounts on spleen histiocytes and peritoneal exudate macrophages. In contrast, M1/70 antigen was found to be absent from erythroid and lymphoid cells. M1/70 antibody precipitated two polypeptides of 190 000 and 105 000 mol. wt. which were present in much greater amounts on peritoneal exudate macrophages than on spleen cells. The expression on phagocytes of two other antigens identified by monoclonal antibodies M1/69 and M1/9.3 was also examined. Monocytes and granulocytes expressed large amounts of M1/69 and low amounts of M1/70 antigen, while in peritoneal exudate macrophages this pattern was dramatically reversed. M1/70 thus defines a differentiation antigen on mononuclear phagocytes and granulocytes, the expression of which is specifically increased during monocyte maturation. This antibody is the first to be described which recognizes a discrete molecule specific to phagocytes.

Journal ArticleDOI
TL;DR: In this paper, Allport's The Nature of Prejudice is extended with an application from attribution theory and an "ultimate attribution error" is proposed: when prejudiced peonle perceive what they regard as a negative act by an outgroup member, they will more than others attribute it dispositionally, often as genetically determined, in comparison to the same act by a ingroup member.
Abstract: Allport's The Nature of Prejudice is a social psychological classic Its delineation of the components and principles of prejudice remains modern, especially its handling of cognitive factors The volume's cognitive contentions are outlined, and then extended with an application from attribution theory An "ultimate attribution error" is proposed: (1) when prejudiced peonle perceive what they regard as a negative act by an outgroup member, they will more than others attribute it dispositionally, often as genetically determined, in comparison to the same act by an ingroup member: (2) wlhen prejudiced people perceive what they regard as a positive act by an outaroup member, they will more than others attribute it in comparison to the same act by an ingroup member to one or more of the following: (a) "the exceptional case," (b) luck or special advantage, (c) hig,h motivation and effort, and (d) manipulable situational context Predictions are advanced as to which of these responses will be adopted and under

Journal ArticleDOI
Warren Siegel1
TL;DR: In this article, a modified form of dimensional regularization is introduced which manifestly preserves gauge invariance, unitarity, and global supersymmetry, and also considers its application to supergravity.

Journal ArticleDOI
TL;DR: A program of selective primary health care is compared with other approaches and suggested as the most cost-effective form of medical intervention in the least developed countries.
Abstract: Priorities among the infectious diseases affecting the three billion people in the less developed world have been based on prevalence, morbidity, mortality and feasibility of control. With these priorities in mind a program of selective primary health care is compared with other approaches and suggested as the most cost-effective form of medical intervention in the least developed countries. A flexible program delivered by either fixed or mobile units might include measles and diphtheria-pertussis-tetanus vaccination, treatment for febrile malaria and oral rehydration for diarrhea in children, and tetanus toxoid and encouragement of breast feeding in mothers. Other interventions might be added on the basis of regional needs and new developments. For major diseases for which control measures are inadequate, research is an inexpensive approach on the basis of cost per infected person per year.

Journal ArticleDOI
12 Jul 1979-Nature
TL;DR: The neuronal structure and connectivity underlying receptive field organisation of cells in the cat visual cortex have been investigated using a micropipette filled with a histochemical marker to visualise the dendritic and axonal arborisations of functionally identified neurones.
Abstract: The neuronal structure and connectivity underlying receptive field organisation of cells in the cat visual cortex have been investigated. Intracellular recordings were made using a micropipette filled with a histochemical marker, which was injected into the cells after their receptive fields had been characterised. This allowed visualisation of the dendritic and axonal arborisations of functionally identified neurones

Journal ArticleDOI
01 May 1979-Nature
TL;DR: Growth rates of natural phytoplankton populations in oceanic waters may be near maximal and hence non-nutrient limited, but the uniformly low biomass and residual nutrient levels in such waters does not preclude the possibility of high growth rates because Zooplankon grazing and nutrient regeneration within the euphotic zone may keep this highly dynamic system in a balanced state.
Abstract: The chemical composition of oceanic phytoplankton (by atoms) typically occurs in the proportions C106 N16 P1. Yet, in laboratory growth conditions these proportions are only observed for marine phytoplankton at high growth rates when non-nutrient limitation is approached. Thus growth rates of natural phytoplankton populations in oceanic waters may be near maximal and hence non-nutrient limited. The uniformly low biomass and residual nutrient levels in such waters does not preclude the possibility of high growth rates because Zooplankton grazing and nutrient regeneration within the euphotic zone may keep this highly dynamic system in a balanced state.

Journal ArticleDOI
TL;DR: Coordinate control of BALB/c 3T3 cell growth in vitro by competence factors and somatomedins may be a specific example of a common pattern of growth regulation in animal tissues.
Abstract: Quiescent BALB/c 3T3 cells exposed briefly to a platelet-derived growth factor (PDGF) become "competent" to replicate their DNA but do not "progress" into S phase unless incubated with growth factors contained in platelet-poor plasma. Plasma from hypophysectomized rats is deficient in progression activity; it does not stimulate PDGF-treated competent cells to synthesize DNA, demonstrating that somatomedin C is required for progression. Various growth factors were tested for progression activity and competence activity by using BALB/c 3T3 tissue culture assays. Multiplication stimulating activity and other members of the somatomedin family of growth factors are (like somatomedin C) potent mediators of progression. Other mitogenic agents, such as fibroblast growth factor, are (like PDGF) potent inducers of competence. Growth factors with potent progression activity have little or no competence activity and vice versa. In contrast, simian virus 40 provides both competence and progression activity. Coordinate control of BALB/c 3T3 cell growth in vitro by competence factors and somatomedins may be a specific example of a common pattern of growth regulation in animal tissues.

Journal ArticleDOI
TL;DR: In this article, a conceptual model and a calculational procedure for the study of the electronic structure of metallic compounds are presented, which consists of spherical atoms compressed into finite volumes appropriate to the solid.
Abstract: We present a conceptual model and calculational procedure for the study of the electronic structure of metallic compounds. The model consists of spherical atoms compressed into finite volumes appropriate to the solid. The model involves no adjustable or experimentally derived parameters. All contributions to the total energy (other than the Madelung energy) are obtained from independent compressed-atom calculations. Interatomic interactions enter the calculations through the electronic configuration (the distribution of the valence charge among $s$, $p$, $d$, etc., states) and boundary conditions which give the atomic valence levels a finite width. These environmental constraints, which specify the state of the compressed atoms, are obtained from energy-band calculations. For the latter we introduce a new method, which we call the augmented-spherical-wave (ASW) method to stress its conceptual similarity to Slater's augmented-plane-wave (APW) method. The ASW method is a direct descendant of the linear-muffin-tin-orbitals technique introduced by Andersen; when applied to pure metals, it yields results which closely approximate those of the much more elaborate Korringa-Kohn-Rostoker calculations of Moruzzi, Williams, and Janak. The combined ASW compressed-atom procedure is tested on (i) the empty lattice, (ii) the pure metals Na, Al, Cu, and Mo, and (iii) the ordered stoichiometric compounds NaCl, NiAl, and CuZn. Finally, we demonstrate the utility of the procedure by using it to study the anomalous tendency of Ni and Pd (as compared to their Periodic Table neighbors Co, Cu, Rh, and Ag) to form hydride phases. We have calculated the total energies of the six pure metals and their monohydrides. The total energy differences exhibit the anomaly and an analysis of quantities internal to the calculation reveals its origin.

Journal ArticleDOI
01 Jan 1979
TL;DR: In this paper, the authors established global convergence for a class of adaptive control algorithms applied to discrete time MIMO deterministic linear systems and showed that the algorithms will ensure that the system inputs and outputs remain bounded for all time and that the output tracking error converges to zero.
Abstract: This paper establishes global convergence for a class of adaptive control algorithms applied to discrete time multi-input multi-output deterministic linear systems. It is shown that the algorithms will ensure that the system inputs and outputs remain bounded for all time and that the output tracking error converges to zero.


Journal ArticleDOI
01 Jun 1979-Science
TL;DR: The observed resonance scattering of solar hydrogen Lyman α by the atmosphere of Jupiter and the solar occultation experiment suggest a hot thermosphere (≥ 1000 K) wvith a large atomic hydrogen abundance.
Abstract: The global hydrogen Lyman alpha, helium (584 angstroms), and molecular hydrogen band emissions from Saturn are qualitatively similar to those of Jupiter, but the Saturn observations emphasize that the H(2) band excitation mechanism is closely related to the solar flux. Auroras occur near 80 degrees latitude, suggesting Earth-like magnetotail activity, quite different from the dominant Io plasma torus mechanism at Jupiter. No ion emissions have been detected from the magnetosphere of Saturn, but the rings have a hydrogen atmosphere; atomic hydrogen is also present in a torus between 8 and 25 Saturn radii. Nitrogen emission excited by particles has been detected in the Titan dayglow and bright limb scans. Enhancement of the nitrogen emission is observed in the region of interaction between Titan's atmosphere and the corotating plasma in Saturn's plasmasphere. No particle-excited emission has been detected from the dark atmosphere of Titan. The absorption profile of the atmosphere determined by the solar occultation experiment, combined with constraints from the dayglow observations and temperature information, indicate that N(2) is the dominant species. A double layer structure has been detected above Titan's limb. One of the layers may be related to visible layers in the images of Titan.

Journal ArticleDOI
18 Oct 1979-Nature
TL;DR: The authors have isolated a calcium-dependent regulatory protein from macrophages and call it gelsolin, providing a possible link to abundant indirect evidence implicating calcium in the regulation of locomotion, secretion and endocytosis.
Abstract: The peripheral cytoplasm of macrophages is involved in the control of locomotion, secretion and endocytosis, events common to many eukaryotic cells. During these activities, the cortical cytoplasm, which contains numerous actin filaments1,2, appears to undergo reversible gel–sol transformations3: cycles of gelation and solation are demonstrable in suitably prepared macrophage extracts, and the gels contain tangled actin filaments4. These changes in consistency of cytoplasmic actin may regulate motile events in the macrophage periphery. Calcium in micromolar concentrations prevents gelation of crude macrophage cytoplasmic extracts4, providing a possible link to abundant indirect evidence implicating calcium in the regulation of locomotion, secretion and endocytosis5. Similar calcium-sensitive gelation phenomena occur in crude cell extracts from diverse cell types and may have a relevance for control of cell movements in general6–11. Actin gelation results from the cross-linking of actin filaments (F-actin) by other proteins. In macrophages, a high molecular weight actin-binding protein (ABP) is the principal actin cross-linking protein12. Cross-linking of actin by these purified actin-binding proteins, however, is insensitive to changes in the calcium concentration4,12, so that another factor must mediate the expression of a calcium effect. We have now isolated such a calcium-dependent regulatory protein from macrophages and call it gelsolin.


Journal ArticleDOI
TL;DR: In this paper, it was shown that the dynamical symmetry breakdown of a gauge symmetry can lead to simple relations among the masses of intermediate vector bosons, and that the symmetry breakdown can in some cases lead to a simple relation among the mass of a vector boson.
Abstract: It is shown that the dynamical symmetry breakdown of a gauge symmetry can in some cases lead to simple relations among the masses of intermediate vector bosons.

Journal ArticleDOI
Edward Witten1
TL;DR: In this article, it is argued that the most attractive resolution of these discrepancies is the possibility that quantum corrections cause the instanton gas to disappear in QCD, and a two-dimensional model is described in which it can be seen explicitly that such a disappearance takes place.