Showing papers by "New York University published in 1968"

Money-wage dynamics and labor-market equilibrium

Abstract: This chapter discusses money-wage dynamics and labor-market equilibrium. A generalized excess-demand theory of the rate of change of the average money-wage rate has been developed for frictional labor markets that allocate heterogeneous jobs and workers without having perfect information and market clearance by auction. There are two explanatory variables: the vacancy rate and the unemployment rate. The unemployment rate and the rate of change of employment are shown to be joint proxies for the vacancy rate. Hence, generalized excess demand can be regarded as a derived function of the unemployment rate and the rate of change of employment. This relationship is the augmented Phillips curve. Some of its properties are deduced. Equilibrium entails equality between the actual and expected rates of wage change. The steady-state equilibrium locus is implied to be a vertical line at a unique steady-state equilibrium unemployment rate. This is consistent with the usual theory of anticipated inflation. But if there are downward money-wage rigidities, then, up to a point, every one percentage point increase of the expected rate of wage change produces less than a one percentage point increase of the actual rate of wage change. The steady-state equilibrium locus will then have the characteristic negative slope of the Phillips curve in the range of large unemployment rates. But at sufficiently small unemployment rates, equilibrium is impossible and under the adaptive expectations theory, an explosive hyperinflation will result.

Entrepreneurship in Economic Theory

Abstract: Examines the historic inability of economic theory to develop a formal analysis of entrepreneurship. The entrepreneur is the major catalyst to the process of economic growth, a central force in both micro and macro economics. Despite this reality, in formal theory, the entrepreneur's role has historically been conspicuously absent. The economic models call for no entrepreneurial initiative, so that theoretically, business people remain passive "automaton maximizers." In fact, contributors from the disciplines of psychology and sociology have made more significant advances - by analyzing social and cultural conditions for entrepreneurship - than have economic theorists. Though it is decided that the supply of entrepreneurship, the entrepreneur's strategies, attitudes to risk, and idea sources cannot be analyzed in a systematic manner, the encouragement of these entrepreneurial behaviors and activities can be theoretically advanced. Theory, then, should consider not how the entrepreneur bears risk or employs R&D, but how the marginal cost of risk-bearing can be reduced, and what economic conditions make R&D easiest and most effective. These theoretical questions clearly bear upon policymaking, since, it is argued, the key to stimulating economic growth is the establishment of policies encouraging entrepreneurship. (CJC)

Receptors for complement on leukocytes

Abstract: Sheep red blood cells sensitized by 7S, but not by 19S rabbit anti-Forssman antibodies, adhere and form rosettes on mouse macrophages and on a few monocytes and polymorphonuclear cells (PMN). When, however, C' factors from mouse serum are added to the antigen-19S antibody complex (EAC'), rosettes are formed on most mouse peritoneal macrophages and PMN and on a few monocytes. In addition EAC' also adheres to 10-25% of lymph node lymphocytes but not to thymus lymphocytes. EAC' prepared with 7S anti-Forssman antibodies has identical properties. The adherence of red cells induces an increase in the membrane activity of the leukocytes and causes injury to the red cells which rapidly become deformed and fragmented. Adherence of EAC' occurs at 37 degrees C and is minimal at 4 degrees C. Probably only the first four C' components are involved in this phenomenon as mouse serum deficient in C'5 or rabbit serum, deficient in C'6 can be used as a source of C' components. Treatment of EAC' with EDTA does not modify its leukocyte-adherence properties. The adherence of EAC' to the leukocytes is not inhibited in the presence of serum. The receptors for C' on macrophages, PMN, and monocytes differ from those found on lymphocytes. Rosette formation by EAC' on macrophages, PMN, and monocytes depends on divalent cations (Mg(++)) and can be reversed by Na(3)H EDTA, while adherence to lymphocytes is independent of these ions and occurs in the presence of 0.01 M Na(3)H EDTA. Both types of receptors for C' components are destroyed by trypsin treatment of the leukocytes, in contrast with the receptors for 7S antibodies on the same cells which persist after enzyme treatment.

Regulatory effect of antibody on the immune response.

Abstract: Publisher Summary This chapter deals with the regulatory effect of antibody on antibody formation. It is possible to analyze those factors that influence the process of antibody synthesis. Certainly antibody, the end product of the process, is among the most potent and specific of inhibitors of antibody synthesis. That this inhibition results from the interaction of antibody with antigen neutralizing the immunogenicity of the latter seems likely, and the evidence for this is critically presented. The potential use of this mechanism is suggested by its effectiveness in the enhancement of tissue grafts, its use in the therapeutic prevention of anti-D antibody responses in mothers of Rh-incompatible fetuses, and its possible role in the induction of some types of immunological tolerance. The immune response represents a predictable series of events, characterized by the sequential appearance of several classes of γ-globulin antibody molecules and the expression of various cell-mediated immune reactions. One mechanism is described for regulating the concentration of immunoglobulin (IgG) in the circulation. The mechanism operates by increasing the catabolic rate of IgG when the serum concentration is abnormally increased as, for example, in multiple myeloma. Two mechanisms are described both of which regulate the immune response. These are alteration of antigenic stimulation and suppression of the immune response by passive transfer of specific antibodies prior to or shortly after administration of antigen.

Mediators of inflammation in leukocyte lysosomes. IX. Elastinolytic activity in granules of human polymorphonuclear leukocytes.

Abstract: The present study demonstrates that a granule fraction derived from human polymorphonuclear leukocytes possesses elastinolytic activity, and that the latter can be separated from the collagenase present in these cells. Properties of the human leukocyte elastase differ sufficiently from those of pancreatic elastases of different species as to suggest that the former enzyme is a distinct and separate entity. Thus, soybean trypsin inhibitor and salivary kallikrein inhibitor (Trasylol) fail to inhibit elastolysis by the pancreatic enzyme, but do inhibit the leukocyte elastinolytic agent. Elastolysis by human leukocyte granule extract does not show significant salt inhibition, whereas that catalyzed by pancreatic elastase is markedly reduced when ionic strength is increased to physiological levels. The leukocyte granule extract is at least 10 times more resistant to serum elastase inhibitor than is the purified pancreatic enzyme. Both enzymes show optimal elastolysis above pH 8.5, but the leukocyte factor still retains 50% of its maximal elastolytic activity at pH 6–7; whereas the activity of the pancreatic enzyme falls to 10% or less of its maximal value under the same conditions. The foregoing characteristics of the human leukocyte elastase suggest that it, rather than pancreatic (serum) elastase, may mediate pathological elastolysis during acute arteritis in man. In keeping with this suggestion, the present experiments also show that elastica staining of human arterial vessels is reduced by incubation of tissues with human leukocyte granule extracts in vitro.

Observations of the Urban Heat Island Effect in New York City

Abstract: Differences in the temperature fields through the lowest 700 m of the atmosphere in and around New York City during the hours near sunrise are analyzed. Data were obtained by an instrumented helicopter on 42 predetermined test mornings from July 1964 to December 1966. Results show urban surface temperature inversions to be less intense, and far less frequent, than those in the surrounding non-urban regions. A high frequency of weak elevated inversion layers at an average height of 310 m was observed over the city. The average intensity of the urban heat island, i.e., urban temperature excess, was a maximum near the surface and decreased to zero at 300 m. On mornings with relatively strong urban elevated inversion layers the heat island extended to well over 500 m. For more than two-thirds of the test mornings there existed an elevated “cross-over layer” in which rural temperatures were higher than urban temperatures. The magnitude of the cross-over effect was less than that of the heat island effect.

Quantum field theory of particles with both electric and magnetic charges.

Abstract: The quantum field theory of particles with both electric and magnetic charges is developed as an obvious extension of Schwinger's quantum field theory of particles with either electric or magnetic charge. Two new results immediately follow. The first is the chiral equivalence theorem which states the unitary equivalence of the Hamiltonians describing the system of particles with electric and magnetic charges ${e}_{n}$, ${g}_{n}$ and the system with charges ${{e}_{n}}^{\ensuremath{'}}=cos\ensuremath{\theta}$, ${e}_{n}+sin\ensuremath{\theta}{g}_{n}$, ${{g}_{n}}^{\ensuremath{'}}=\ensuremath{-}sin\ensuremath{\theta}{e}_{n}+cos\ensuremath{\theta}{g}_{n}$. This result holds in particular in the absence of physical magnetic charges. The second result is that if physical magnetic charges do occur, then, in consequence of chiral equivalence, the charge quantization condition applies, not to the separate products ${e}_{m}{g}_{n}$, but to the combinations ${e}_{m}{g}_{n}\ensuremath{-}{g}_{m}{e}_{n}$, which must be integral multiples of $4\ensuremath{\pi}$. The general solution of this condition leads to the introduction of a second elementary quantum of electric charge ${e}_{2}$, the electric charge on the Dirac monopole, besides the first elementary charge ${e}_{1}$, the charge on the electron. There are no other free parameters.

Inhibition of Adenosine Diphosphate-Induced Secondary Aggregation and Other Platelet Functions by Acetylsalicylic Acid Ingestion∗

Abstract: SummarySecondary aggregation of platelets was produced in 8 of 10 normal subjects by a critical concentration of adenosine diphosphate (ADP) ranging from 1.0-2.0 μM. Shortening of the Russell Viper Venom clotting time and release of serotonin-14C were also observed with the critical concentration of ADP or with higher levels, but did not occur in the two subjects who showed only primary aggregation in response to ADP. Ingestion of 1.3 gm of acetylsalicylic acid in a divided dose 1 and 2 hours prior to testing abolished secondary aggregation, serotonin release, and platelet factor-3 activation induced by ADP, as well as aggregation and serotonin release induced by connective tissue particles, but did not affect primary ADP-induced aggregation.

Exactly Soluble Nonrelativistic Model of Particles with Both Electric and Magnetic Charges

Abstract: We consider the quantum-mechanical problem of the interaction of two particles, each with arbitrary electric and magnetic charges. It is shown that if an additional $\frac{1}{{r}^{2}}$ potential, of appropriate strength, acts between the particles, then the resulting Hamiltonian possesses the same higher symmetry as the non-relativistic Coulomb problem. The bound-state energies and the scattering phase shifts are determined by an algebraic and gauge-independent method. If the electric and magnetic coupling parameters are $\ensuremath{\alpha}$ and $\ensuremath{\mu}=0, \ifmmode\pm\else\textpm\fi{}\frac{1}{2}, \ifmmode\pm\else\textpm\fi{}1, \ensuremath{\cdots}$, then the bound states correspond to the representations ${n}_{1}+{n}_{2}=|\ensuremath{\mu}|, |\ensuremath{\mu}|+1, \ensuremath{\cdots}$, ${n}_{1}\ensuremath{-}{n}_{2}=\ensuremath{\mu}$ of $S{U}_{2}\ensuremath{\bigotimes}S{U}_{2}\ensuremath{\sim}{O}_{4}$, and the scattering states correspond to the representations of $SL(2, C)\ensuremath{\sim}O(1, 3)$ specified by ${\mathrm{J}}^{2}\ensuremath{-}{\mathrm{K}}^{2}={\ensuremath{\mu}}^{2}\ensuremath{-}{\ensuremath{\alpha}}^{\ensuremath{'}2}\ensuremath{-}1$, $\mathrm{J}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{K}={\ensuremath{\alpha}}^{\ensuremath{'}}\ensuremath{\mu}$, with ${\ensuremath{\alpha}}^{\ensuremath{'}}=\frac{\ensuremath{\alpha}}{v}$. Thus, as $\ensuremath{\alpha}$ and $\ensuremath{\mu}$ are varied, all irreducible representations of ${O}_{4}$ and all irreducible representations in the principal series of $O(1, 3)$ occur. The scattering matrix is expressed in closed form, and the differential cross section agrees with its classical value. Some results are obtained which are valid in a relativistic quantum field theory. The $S$ matrix for spinless particles is found to transform under rotations like a $\ensuremath{\mu}\ensuremath{\rightarrow}\ensuremath{-}\ensuremath{\mu}$ helicity-flip amplitude, which contradicts the popular assumption that scattering states transform like the product of free-particle states. It is seen that the Dirac charge quantization condition means that electromagnetic interactions are characterized not by one but by two, and only two, free parameters: the electronic charge $e\ensuremath{\approx}{(137)}^{\ensuremath{-}\frac{1}{2}}$, and the electric charge of the magnetic monopole, whose absolute magnitude is not fixed by the Dirac quantization condition but which defines a second elementary quantum of electric charge.

Studies on the mechanism of tumor inhibition by L-asparaginase. Effects of the enzyme on asparagine levels in the blood, normal tissues, and 6C3HED lymphomas of mice: differences in asparagine formation and utilization in asparaginase-sensitive and -resistant lymphoma cells.

Abstract: L-asparaginases of agouti serum and Escherichia coli cause a profound lowering in the level of free asparagine in the blood of treated mice and also in the tissues. During treatment, normal tissues and resistant 6C3HED lymphomas survive unharmed with intracellular asparagine levels which are critically low for sensitive lymphomas. An explanation for this contrast between the two types of lymphoma is provided by the finding that resistant cells have not only a higher asparagine synthetic capacity than sensitive cells but appear able to utilize endogenous asparagine preferentially for protein synthesis. Cell-free extracts of resistant cells contain an asparaginase synthetase, but this is not found in preparations from sensitive cells.

Studies on lysosomes. XI. Characterization of a hydrolase-rich fraction from human lymphocytes.

Abstract: Pure suspensions of human lymphocytes were separated from peripheral blood by means of nylon wool, homogenized in 0.34 M sucrose-0.01 M EDTA solution, and fractionated by differential centrifugation. The bulk of acid hydrolase activity was found to be concentrated in a 20,000 g x 20 min granular fraction, whereas nuclear, debris, and supernatant fractions contained lesser concentrations of hydrolases. Acid hydrolase activity present in the granular fraction showed appropriate "latency" as judged by its dose-dependent release into the 20,000 g x 20 min supernatant after exposure to membrane-disruptive agents such as streptolysin S, filipin, and lysolecithin. Heparin proved to be necessary in the suspending medium so that reproducible homogenization and cell fractionation could be obtained. Even excessive contamination of lymphocyte suspensions with platelets did not appreciably alter the acid hydrolase activity of lymphocyte homogenates or the distribution of enzymes in subcellular fractions. Discontinuous density-gradient centrifugation of a 500 g x 10 min supernatant, containing both acid hydrolase-rich organelles and mitochondria, resulted in partial resolution of hydrolase-rich organelles from mitochondria. Fine structural studies of the intact lymphocytes showed the presence of acid phosphatase-positive, membrane-bounded organelles. Electron microscopy of the "large granule" (20,000 g x 20 min) fraction of such lymphocytes demonstrated 80–90% mitochondria, 5–10% platelets, and 5–10% membrane-bounded acid phosphatase-positive structures. The data indicate the presence in human peripheral blood lymphocytes of acid hydrolase-rich granules which possess many of the biochemical and structural characteristics of lysosomes in other tissues.

Vascular Injury and Lysis of Basement Membrane in vitro by Neutral Protease of Human Leukocytes

Abstract: Frozen and thawed granules of human, peripheral-blood leukocytes rapidly produce hemorrhage when injected into animal tissues. The effect is blocked by inhibitors of proteolysis. The granule extract can digest vascular basement membrane in vitro at neutral pH. In addition, basement membranes of blood vessels damaged in vivo by the leukocyte fraction are found to be attenuated when examined by electron microscopy. The proteases of human leukocyte granules differ in several important respects from known lysosomal cathepsins and trypsin-like esterases. Polymorphonuclear neutrophils are a major source of the neutral proteases present in circulating white cells, and release these enzymes during phagocytosis of immune complexes.

Amnesia: a function of the temporal relation of footshock to electroconvulsive shock.

Abstract: When rats received a brief footshock upon stepping off an elevated platform, and an electroconvulsive shock 30 seconds or 6 hours afterward, amnesia was not observed 24 hours later. If a second footshock (noncontingent) was delivered 0.5 second before the electroconvulsive shock, amnesia was observed. The amnesia was temporary if conditioning was strong and permanent if conditioning was weak.

Effects of Number of Alternatives on the Psychological Refractory Period

Abstract: The effects of changing the number of choices in the first response on “psychological refractoriness” were found to be partially consistent with intermittency theory but modifications may be needed to explain the results when the number of choices in the second response is increased.

Interaction of Staphylococcal α-Toxin with Artificial and Natural Membranes

Abstract: Comparison of hemolytic activity and chromate-releasing activity of partially purified preparations of staphylococcal alpha-toxin indicated the presence of a lytic factor other than alpha-toxin. This lytic release factor (RF) was isolated from the preparations and was shown to be active against both lipid spherules and erythrocytes. Heat-purified alpha-toxin (HP alpha-toxin) disrupted spherules, with the formation of fragments which always showed the presence of ring structures similar in dimensions (ca. 90 A) to pure alpha 12S-toxin. The interaction of HP alpha-toxin with spherules was accompanied by loss of hemolytic activity and adsorption of toxic protein. The alpha 12S-toxin, although only weakly hemolytic, was shown to be lytic for spherules. An alpha 12S-free toxin rapidly disrupted spherules, with formation of fragments with attached rings similar in dimensions to the alpha 12S molecule. Lipid monolayer experiments showed that HP alpha-toxin could penetrate lipid monolayers by virtue of a hydrophobic interaction. Effects of HP alpha-toxin on rabbit and human erythrocyte ghosts were similar to its effects on spherules, in that rings appeared on membrane fragments. Toxin-lysed rabbit erythrocytes showed similar rings on the resulting membrane fragments. However, rings were not seen on toxin-treated rabbit erythrocytes in the prelytic lag phase; this result and the fact that human erythrocytes are largely insensitive to alpha-toxin were interpreted as evidence against a lytic mechanism involving ring formation as the primary event. Rings were interpreted as toxin polymers similar to alpha 12S molecules, formed from specifically orientated active toxin molecules at the surface of lipid structures. Possible mechanisms for toxin lysis of spherules and erythrocytes are discussed.

Studies on the control of antibody synthesis ii. effect of antigen dose and of suppression by passive antibody on the affinity of antibody synthesized

Abstract: The effect of antigen dose on the kinetics of circulating antibody synthesis and on antibody affinity was studied in a haptenic system. High doses of antigen resulted, early in immunization, in higher concentrations of antibody followed later in the immune response by decreased serum levels of antibody as compared with lower doses of antigen. The affinity of the initial antibody synthesized was very similar over a wide antigen dose range. Subsequently, however, a rapid rise in affinity was seen in animals immunized with low doses of antigen, while relatively little change in affinity was seen in animals immunized with higher antigen doses. Suppression of active antibody formation by passive antiserum led to an increase in antibody affinity. The results are discussed in terms of the mechanisms involved in the selection of a population of cells to participate in the immune response and the mechanisms whereby antigen dose and circulating antibody function to control antibody synthesis.

Production of L-asparaginase II by Escherichia coli.

Abstract: l-Asparaginase II was synthesized at constant rates by Escherichia coli under anaerobic conditions. The enzyme was produced optimally by bacteria grown between pH 7 and 8 at 37 C. Although some enzyme was formed aerobically, between 100 and 1,000 times more asparaginase II was produced during anaerobic growth in media enriched with high concentrations of a variety of amino acids. Bacteria grown under these conditions should provide a rich starting material for the large-scale production of the enzyme. No single amino acid specifically induced the synthesis of the asparaginase, nor did l-asparagine, even when it was used as the only source of nitrogen. The enzyme was produced at lower rates in the presence of sugars; glucose was the most inhibitory.

Lytic agents, cell permeability, and monolayer penetrability.

Abstract: Cell lysis induced by lytic agents is the terminal phase of a series of events leading to membrane disorganization and breadkdown with the release of cellular macromolecules. Permeability changes following exposure to lytic systems may range from selective effects on ion fluxes to gross membrane damage and cell leakage. Lysis can be conceived as an interfacial phenomenon, and the action of surface-active agents on erythrocytes has provided a model in which to investigate relationships between hemolysis and chemical structure, ionic charge, surface tension lowering, and ability to penetrate monolayers of membrane lipid components. Evidence suggests that lysis follows the attainment of surface pressures exceeding a "critical collapse" level and could involve membrane cholesterol or phospholipid. Similarities of chemical composition of membranes from various cell types could account for lytic responses observed on interaction with surface-active agents. Cell membranes usually contain about 20–30 % lipid and 50–75 % protein. One or two major phospholipids are present in all cell membranes, but sterols are not detectable in bacterial membranes other than those of the Mycoplasma group. The rigid cell wall in bacteria has an important bearing on their response to treatment with lytic agents. Removal of the wall renders the protoplast membrane sensitive to rapid lysis with surfactants. Isolated membranes of erythrocytes and bacteria are rapidly dissociated by surface-active agents. Products of dissociation of bacterial membranes have uniform behavior in the ultracentrifuge (sedimentation coefficients 2–3S). Dissociation of membrane proteins from lipids and the isolation and characterization of these proteins will provide a basis for investigating the specificity of interaction of lytic agents with biomembranes.

On the asymptotic exactness of the Bogoliubov approximation for many boson systems

Abstract: The Bogoliubov approximation for many boson systems consists in replacing the field operatorsa 0 anda 0 + byc-numbers, to be determined by an extremum condition. Here we formulate the approximation in terms of coherent states of the condensed particles, and prove that for reasonable interactions it gives the exact values of the thermodynamical functions in the infinite volume limit.

Serum antinuclear antibodies in progressive systemic sclerosis (scleroderma)

Abstract: Sera from 47 patients with PSS were studied for the presence of antinuclear antibodies. Antinuclear antibodies were present in 60 per cent of the sera in a titer of1:16 or greater. In most cases the titer was low, but a titer of1:256 or greater was present in sera from 6 patients. The pattern of nuclear fluorescence was most commonly that of fine or large speckles. Most sera contained both IgC and IgM antinuclear antibodies. There was no relation between duration of disease or severity of disease and the presence of antinuclear antibodies. Similarly, no correlation could be demonstrated between clinical findings and the immunoglobulin class, titer, or staining pattern of antinuclear antibody. The prevalence of high tilers of antinuclear antibodies was greater in patients with hypergammaglobulinemia than in those with normal levels of gamma globulin. Rheumatoid factor was present in 33 per cent of sera. Patients with high liters of rheumatoid factor tended to have high tilers of antinuclear antibodies. Antinuclear antibodies were found in low titer in 7 per cent of blood relatives less than 60 years of age. The number of sera with antinuclear antibodies was slightly higher in the non-aged relatives of patients with systemic lupus erythematosus (11 per cent), while the prevalence in relatives of patients with chronic discoid lupus (2 per cent) was similar to that of a group of healthy student nurses. The results reveal that antinuclear antibodies of a speckled pattern are commonly present in sera from patients with FSS and appear to be unrelated to the duration or severity of the disease. The peripheral pattern of nuclear fluorescence produced by sera from acutely ill patients with systemic lupus erythematosus was not observed with any of the sera of patients with PSS. These obs 3 ervations emphasize the fact that the presence of antinuclear antibodies in general is not diagnostic of any one disease, and indicate that the pattern of nuclear fluorescence produced by the antinuclear antibodies may aid in confirmation of clinical diagnosis.