Showing papers by "New York University published in 1969"
TL;DR: In this paper, the general method for constructing invariant phenomenological Lagrangians is described, where the fields are assumed to transform according to (nonlinear) realizations of an internal symmetry group, given in standard form.
Abstract: The general method for constructing invariant phenomenological Lagrangians is described. The fields are assumed to transform according to (nonlinear) realizations of an internal symmetry group, given in standard form. The construction proceeds through the introduction of covariant derivatives, which are standard forms for the field gradients. The case of gauge fields is also discussed.
1,284 citations
TL;DR: In this paper, the basic mechanism of tropical cyclones was investigated by constructing a numerical-dynamical model on such a model, and the model showed that the energy required for driving the vortex comes from the latent heat of condensation released by tall convective clouds around the center, and that the frictionally induced inflow in the vortex plays a major role in supporting the continued activity of convective cloud.
Abstract: The tropical cyclone is a solitary creature of the tropical oceans accompanied by violent rotating winds and torrential rain. Observational studies and diagnostic analyses leave little doubt that the energy required for driving the vortex comes from the latent heat of condensation released by tall convective clouds around the center, and that the frictionally induced inflow in the vortex plays a major role in supporting the continued activity of convective clouds. This dual character with respect to important scales of motion poses a great difficulty in investigating the dynamics of tropical cyclones as time-dependent phenomena. However, in order to understand the large-scale aspects of tropical cyclones, one may formulate the role of convective clouds in terms of cyclone-scale variables with only implicit consideration of the dynamics of individual clouds. The present study is an attempt to understand the basic mechanism of tropical cyclones by constructing a numerical-dynamical model on such a ...
698 citations
TL;DR: In this article, the convergence of the Fcynman integrand is proved by an application of the power counting theorem, and the convergence is proved for the non-algebraic version of renormalization in momentum space.
Abstract: Bogoliubov’s method of renormalization is formulated in momentum space. The convergence of the rcnonnalizcd Fcynman integrand is proved by an application of the power counting theorem.
557 citations
TL;DR: In this paper, the Rarita-Schwinger equation in an external electromagnetic potential is shown to be equivalent to a hyperbolic system of partial differential equations supplemented by initial conditions.
Abstract: The Rarita-Schwinger equation in an external electromagnetic potential is shown to be equivalent to a hyperbolic system of partial differential equations supplemented by initial conditions. The wave fronts of the classical solutions are calculated and are found to propagate faster than light. Nevertheless, for sufficiently weak external potentials, a consistent quantum mechanics and quantum field theory may be established. These, however, violate the postulates of special relativity.
394 citations
TL;DR: Responding by pigeons on one key of a two-key chamber alternated the color of the second key, on which responding produced food according to a variable-interval schedule of reinforcement, to find relative overall rates of responding and relative times in the presence of a key color approximated the proportions of reinforcements obtained in the absence of that color.
Abstract: Responding by pigeons on one key of a two-key chamber alternated the color of the second key, on which responding produced food according to a variable-interval schedule of reinforcement. From time to time, reinforcement would be available for a response, but in the presence of a particular stimulus, either red or green light on the key. Red or green was chosen irregularly from reinforcement to reinforcement, so that a proportion of the total number of reinforcements could be specified for each color. Experimental manipulations involved variations of (1) the proportions for each color, (2) changeover delay, or, alternatively, (3) a fixed-ratio changeover requirement. The main findings were: (1) relative overall rates of responding and relative times in the presence of a key color approximated the proportions of reinforcements obtained in the presence of that color, while relative local rates of responding changed little; (2) changeover rate decreased as the proportions diverged from 0.50; (3) relative overall rate of responding and relative time remained constant as the changeover delay was increased from 2 to 32 sec, with reinforcement proportions for red and green of 0.75 and 0.25, but they increased above 0.90 when a fixed-ratio changeover of 20 responses replaced the changeover delay; (4) changeover rate decreased as the delay or fixed-ratio was increased.
390 citations
TL;DR: Biopsy specimens were taken from apparently healthy persons who were screened to eliminate, as far as possible, gross pathosis and variables which might interfere with normal tissue regeneration.
356 citations
TL;DR: Four mutations conferring recombination deficiency have been cotransduced with cysC and pheA and, despite the different degrees of apparent dominance, all may lie in the recA gene.
Abstract: Four mutations conferring recombination deficiency (recA1, recA13, rec-12, and rec-65) have been cotransduced with cysC and pheA; consequently they lie between 53 and 50 on the standard genetic map of Escherichia coli. The four mutations show different degrees of apparent dominance in transient rec+/rec− zygotes, and the degree of apparent dominance of a particular mutation was shown to be a characteristic of that mutation, not a reflection of other genetic differences in the original rec mutant strain. All four mutations map at similar distances from cysC and pheA and, despite the different degrees of apparent dominance, all may lie in the recA gene.
334 citations
TL;DR: The proportion of the initial lung burden of radioactive particles removed during the first 24 hours provided a functional measure of tracheo-bronchial deposition and, for each individual subject, head and tracheobronchia deposition increased with increasing particle size.
Abstract: The effect of particle size on the regional deposition of aerosols inhaled through the mouth was determined in 93 studies on 34 subjects. The test aerosols were spherical monodisperse insoluble iron oxide particles (specific gravity 2.5) containing radioactive tags, ranging in median unit density diameter from 2.1 to 12.5-microns (σ ≅ 1.08). Particles deposited on the bronchial tree were translocated to the stomach by mucociliary clearance which was essentially complete within the first day. The proportion of the initial lung burden of radioactive particles removed during the first 24 hours provided a functional measure of tracheo-bronchial deposition. A portion of the inhaled aerosol was deposited in the head by impaction. As an impactor, the tracheobronchial tree is more efficient. For each individual subject, head and tracheobronchial deposition increased with increasing particle size. Alveolar depositions decreased with size for particles larger than 4-microns.
321 citations
TL;DR: These studies indicate that the lytic effects of melittin upon biological membranes may be due to a similar reaction with structural phospholipids.
299 citations
TL;DR: Two Typen von synthetischen Karbonatapatiten untersucht: solche, die sich in wässrigen Medien bildeten, und andere, die bei hohen Temperaturen und unter Ausschluss von Wasser entstanden.
Abstract: Um die Art des Karbonateinbaues in die Apatitstruktur zu klaren, wurden zwei Typen von synthetischen Karbonatapatiten untersucht: solche, die sich in wassrigen Medien bildeten, und andere, die bei hohen Temperaturen und unter Ausschluss von Wasser entstanden.
297 citations
TL;DR: In this article, the authors analyzed the non-causality of the spin-one Lagrangian with spin ∆ and showed that it behaves well when coupled to an external electromagnetic field or via a magnetic dipole moment.
Abstract: We analyze critically what happens when various interaction terms are added to a Lagrangian describing a free particle with spin \ensuremath{\ge}1. Good behavior results when the charged spin-one particle is coupled minimally to an external electromagnetic field or via a magnetic dipole moment. However, with an arbitrary electric quadrupole moment, the spin-one particle propagates noncausally ($vgc$) in an electrostatic field. Noncausal behavior is also found for the neutral vector field with self-coupling $\ensuremath{\lambda}{({W}_{\ensuremath{\mu}}{W}^{\ensuremath{\mu}})}^{2}$. Another kind of disease appears when the spin-two particle is given a charge: A constraint is converted into an equation of motion, so that there are six degrees of freedom instead of the desired five.
TL;DR: The results suggest that sialic acid constituents of the lymphocyte surface play a critical role in ensuring the normal distribution of these cells in the body and imply that reactions involving surface sIALic acid can markedly alter the fate of lymphocytes without "killing" the cells.
Abstract: Evidence has been obtained that incubation of rat lymphocytes with neuraminidase, prior to intravenous transfusion into allogeneic or syngeneic recipients, alters the distribution of the cells. Many enzyme-treated lymphocytes initially become trapped in the liver, and there is a decrease in the selective accumulation of these cells in the lymph nodes and spleen. Subsequently, many enzyme-altered cells emigrate from the liver, concentrate in lymph nodes, and recirculate to the lymph. The results suggest that sialic acid constituents of the lymphocyte surface play a critical role in ensuring the normal distribution of these cells in the body. The findings also imply that reactions involving surface sialic acid can markedly alter the fate of lymphocytes without "killing" the cells.
TL;DR: The outer layers of neutron stars form a solid crust with a calculable rigidity (shear modulus) very soon after the stars are born, and subsequent changes in stellar shape from oblate toward spherical, as the neutron star angular velocity decreases, will induce stresses in the crust until the maximum shear strain which the solid can support is reached as mentioned in this paper.
Abstract: THE outer layers of neutron stars form a solid crust with a calculable rigidity (shear modulus) very soon after the stars are born. Subsequent changes in stellar shape from oblate toward spherical, as the neutron star angular velocity decreases, will induce stresses in the crust until the maximum shear strain which the solid can support is reached. Beyond this yield point there will be a sudden relaxation of the stress, and a very slight change in stellar shape and moment of inertia. The calculated accompanying jump in angular velocity is close to that which has been observed in a pulsar.
TL;DR: The active species of "CO2", i.e. CO2 or HCO3-, utilized in the ribulose diphosphate carboxylase reaction was determined with the use of homogeneous preparations of the spinach enzyme, and data were obtained which are quite compatible with those expected if CO2 is the active species.
TL;DR: The distribution of large dividing lymph node or thoracic duct lymph cells, labeled in vitro with 3H-thymidine, was studied in syngeneic recipient rats after intravenous injection and found that the labeled cells rapidly "homed" to lymphoid tissue and recirculated in the recipient, in a fashion resembling that of small lymphocytes.
Abstract: The distribution of large dividing lymph node or thoracic duct lymph cells, labeled in vitro with (3)H-thymidine, was studied in syngeneic recipient rats after intravenous injection. In most experiments the donor rats had been immunized with Bacillus pertussis 4 days earlier, but in some instances cells from nonimmunized donors were used. In smears, the labeled donor cells had the appearance of large lymphocytes or large pyroninophilic cells. By electronmicroscopy, the majority of labeled donor cells were seen to have only scanty endoplasmic reticulum. It was found that the labeled cells rapidly "homed" to lymphoid tissue and recirculated in the recipient, in a fashion resembling that of small lymphocytes. However, the distribution of labeled cells was found to depend upon the source of the donor cells. Cells from mesenteric lymph nodes or thoracic duct lymph showed a marked preferential accumulation in lymphoid tissue within or adjacent to the intestine, whereas cells from peripheral nodes accumulated preferentially in peripheral lymph nodes. Cells from any of these sources showed an equal tendency to accumulate in the white pulp of the spleen. Suspensions of small lymphocytes, labeled in vitro with (3)H-uridine, did not display a similar tendency to localize preferentially in lymphoid tissue in certain regions. It was also found that large dividing lymph node cells from donors immunized with an antigen (2,4-dinitrophenyl-bovine gamma globulin (DNP-BGG) or B. pertussis) showed a greater tendency to accumulate in a recipient lymph node containing that antigen than in the contralateral node. It was not determined whether the selective accumulation of large dividing lymphoid cells from different sources in lymphoid tissue of different regions in recipients was due to an antigen recognition mechansim or was the result of two different populations of cells with different "homing" mechanisms.
TL;DR: Experiments with S35-labeled SDS suggest that the SDS-protein complex is a loose one and that exchange of SDS with the environment occurs at an exceedingly high rate.
TL;DR: Skin tests were found to be valuable predictive tests for immediate (including anaphylactic) and accelerated urticarial allergic reactions to penicillin.
TL;DR: Tactile stimulation of the siphon and mantle shelf in Aplysia causes a characteristic withdrawal response of the external organs of the mantle cavity and a similar response also occurs spontaneously, mediated by the abdominal ganglion.
Abstract: Tactile stimulation of the siphon and mantle shelf in Aplysia causes a characteristic withdrawal response of the external organs of the mantle cavity. A similar response also occurs spontaneously. Both responses are mediated by the abdominal ganglion and therefore provide an opportunity for correlating cellular functioning and behavior in a relatively simple and well-studied neuronal system. The withdrawal responses are controlled by five identified motor cells which receive two types of synaptic inputs. One set of excitatory connections, activated by tactile stimulation of the siphon and mantle shelf, mediates the defensive withdrawal reflex. A second set of connections is activated by a spontaneous burst of activity in a group of closely coupled interneurons which are excitatory to some of the motor cells and inhibitory to the others. This second set of connections mediates the spontaneous withdrawal response. These two inputs can therefore switch the same population of motor cells from a simple reflex to a more complex, internally organized response.
TL;DR: In this paper, a general method for solving the inverse diffraction problem is presented based on an identity of Bojarski which states that \gamma(x) and \Gamma(p) are a Fourier transform pair.
Abstract: A general method for solving the inverse diffraction problem is presented. It is based on an identity of Bojarski which states that \gamma(x) and \Gamma(p) are a Fourier transform pair. Here \gamma(x) is the characteristic function of the target ( \gamma=1 inside the target, \gamma = 0 outside), p = (2\omega/c)J,\omega is the frequency, J is a unit vector specifying the aspect, and \Gamma(P) can be obtained by measurement of the backscattered electromagnetic far field at frequency \omega = (c/2)|P| and aspect J=|p|^{-1}p . If data is obtained in any subset D of p space, the method yields partial or complete information about the target geometry. It is used to rederive earlier results very simply and to obtain a significant new solution, in which the target geometry is completely determined using frequencies only in a practical frequency band and aspects in a narrow cone.
TL;DR: Two technics have been developed, which make possible the in vitro detection of platelet antibody in patients with idiopathic thrombocytopenic purpura, and systemic lupus erythematosus, and the antiplatelet factor was found to be an immunoglobulin of the IgG class.
TL;DR: The demonstrated convergence of visceral and cutaneous afferent pathways onto common interneurons in the dorsal horn provides a mechanism by which the referral of visceral pain to the skin might be explained.
TL;DR: The aim was to determine whether a strict strain and species specificity occurs in animals vaccinated with sporozoites, or if a much broader spectrum of protective immunity develops.
Abstract: VACCINATION against malarial infections remains a goal to be achieved. Even if it were feasible, it might be difficult to obtain necessary amounts of the parasitic antigen, and only homologous species or strains of the parasite may be immunologically effective. Protective immunity is often a highly strain specific phenomenon as has been shown in experiments using the blood stages of the parasite as the immunizing agent1,2. Strain specificity of the immune response also occurs in natural human malaria3. Our aim was to determine whether a strict strain and species specificity occurs in animals vaccinated with sporozoites, or if a much broader spectrum of protective immunity develops.
TL;DR: The hydrolysis of AT32P by calf brain microsomes appears to be catalyzed by two different enzymatic sites that are inactivated by ouabain, implicated in the mechanism for Na+ and K+ transport across biological membranes.
TL;DR: In this paper, two experiments on free recall are presented in which pairs of related words are presented within the lists and the number of words intervening between the related pair is systematically varied.
TL;DR: The data suggest that escape of granule contents from lysosomes into the joint cavity is sufficient to account for proliferative and degradative changes observed in several forms of clinical and experimental arthritis.
Abstract: From rabbit heterophile leukocytes, granules were prepared which had a high specific activity of acid hydrolases. When lysates of such granules were injected into the skin and joints of other rabbits, acute inflammation was regularly produced. Repeated intraarticular injections led to hypertrophy and hyperplasia of synovial lining cells, round cell infiltration of synovium in the vicinity of blood vessels, pannus formation, and cartilage degradation. The data suggest that escape of granule contents from lysosomes into the joint cavity is sufficient to account for proliferative and degradative changes observed in several forms of clinical and experimental arthritis.