Showing papers by "New York University published in 1981"
Book•
01 Jan 1981TL;DR: The Modern Portfolio Theory as discussed by the authors examines the characteristics and analysis of individual securities as well as the theory and practice of optimally combining securities into portfolios, while presenting advanced concepts of investment analysis and portfolio management.
Abstract: An update of a classic book in the field, Modern Portfolio Theory examines the characteristics and analysis of individual securities as well as the theory and practice of optimally combining securities into portfolios. It stresses the economic intuition behind the subject matter while presenting advanced concepts of investment analysis and portfolio management. Readers will also discover the strengths and weaknesses of modern portfolio theory as well as the latest breakthroughs.
2,476 citations
TL;DR: In this paper, the optimal behavior of a single dealer who is faced with a stochastic demand to trade (modeled by a continuous time Poisson jump process) and facing return risk on his stock and on the rest of his portfolio was examined.
1,416 citations
TL;DR: In this article, a general theory of singular limits in compressible fluid flow and magneto-fluid dynamics is developed, which is broad enough to study a wide variety of interesting singular limits.
Abstract: Many interesting problems in classical physics involve the limiting behavior of quasilinear hyperbolic systems as certain coefficients become infinite. Using classical methods, the authors develop a general theory of such problems. This theory is broad enough to study a wide variety of interesting singular limits in compressible fluid flow and magneto-fluid dynamics including new constructive local existence theorems for the time-singular limit equations. In particular, the authors give an entirely self-contained classical proof of the convergence of solutions of the compressible fluid equations to their incompressible limits as the Mach number becomes small. The theory depends upon a balance between certain inherently nonlinear structural conditions on the matrix coefficients of the system together with appropriate initialization procedures. Similar results are developed also for the compressible and incompressible Navier-Stokes equations with periodic initial data independent of the viscosity coefficients as they tend to zero.
893 citations
TL;DR: In this paper, a framework for organizing role conflict and ambiguity research is proposed, which may assist in consolidating the field and providing an understanding of where we are, what is left to be done and, therefore, direction for future role conflict/ambiguity research.
Abstract: Although research on role conflict and ambiguity has been extensive, there has been only moderate consistency in the focus and results of the research, while several areas of role conflict and ambiguity research are still relatively unexamined. This paper suggests that a framework for organizing the recent research may assist in consolidating the field and providing an understanding of where we are, what is left to be done and, therefore, direction for future role conflict and ambiguity research.
700 citations
TL;DR: The observations made in 1926 that tooth enamel, dentine and bone had x-ray diffraction patterns similar to those of mineral apatltes coupled with the chemically analyzed calcium and phosphate contents, led to the conclusion that the principal inorganic constituents of bone and tooth are basically calcium hydroxyapatite, idealized as CaI0(PO~)6(OH)2 (1,2).
561 citations
Book•
01 Jan 1981TL;DR: Two types of multiphase flow may be distinguished on the basis of their degree of phase separation as mentioned in this paper, where one or more components exist as discrete phase, dispersed in another component forming the continuous phase.
Abstract: Two types of multiphase flow may be distinguished on the basis of their degree of phase separation. One type is dispersed multiphase flow, in which one or more components exist as discrete phase, dispersed in another component forming the continuous phase. The other type is stratified multiphase flow, in which two or more components form continuous phases separated from each other by continuous boundaries.
544 citations
TL;DR: In this paper, the influence of the energy loss of slow projectiles during inelastic collisions on the inner-shell ionization cross sections is treated analytically, and the result agrees with available experimental cross sections for $K$-shell Ionization by protons.
Abstract: The influence of the energy loss of slow projectiles during inelastic collisions on the inner-shell ionization cross sections is treated analytically. The result agrees with available experimental cross sections for $K$-shell ionization by protons. Residual trends in the data may gauge the quality of wave functions employed in calculations of Coulomb ionization cross sections.
542 citations
TL;DR: The ethnicity literature within marketing has infrequently considered relevant subcultural norms in the derivation of hypotheses, the strength of ethnic identification in the grouping of subjects, and the....
Abstract: The ethnicity literature within marketing has infrequently considered relevant subcultural norms in the derivation of hypotheses, the strength of ethnic identification in the grouping of subjects, ...
381 citations
TL;DR: In this paper, the demand for real cash balances deduced from an underlying portfolio model of the financial market is shown to depend upon domestic variables and foreign monetary developments, and the conclusion that domestic monetary policy is fairly ineffective and domestic financial markets are highly vulnerable to changes in foreign financial and monetary developments need to be modified in light of the results presented in this paper.
332 citations
TL;DR: It is concluded that 3000 rad in two weeks is at least as effective as 5000 rad in four weeks in the palliation of brain metastases, even in this relatively favorable patient population.
Abstract: The palliative effectiveness of a short, intensive course of brain irradiation (3000 rad in 2 weeks) was compared to that of a high-dose course (5000 rad in 4 weeks) in a randomized RTOG clinical trial. Eighty percent of the 255 evaluable patients had lung primaries, 7% breast, and 13% other or unknown primaries. Patients with evidence of extra-cranial metastases, uncontrolled primaries, or Class IV Neurologic Function (NFIV) were excluded. Forty-one percent of NFII and 71 % of NFIV patients improved in neurologic function class. For NFII patients, a significantly greater improvement rate was obtained with the short course than with the long course. Otherwise there were no significant differences between the two regimens with respect to palliation of symptoms, improvement rate, median time to progression, cause of death, or median survival. We conclude that 3000 rad in two weeks is at least as effective as 5000 rad in four weeks in the palliation of brain metastases, even in this relatively favorable patient population.
319 citations
TL;DR: It is suggested that cells in the dopamine-rich areas of the mesencephalon can be characterized both on the basis of their content of peptide and/or catecholamine and of their responsiveness to cholecystokinin-like peptides.
TL;DR: It is reported here that addition of hypoxanthine to the culture medium permits the production of mature, infectious P. falciparum gametocytes on a regular basis.
Abstract: The form of malaria caused by Plasmodium falciparum is probably the most important infectious disease of man. In tropical Africa alone, where malaria affects almost the entire population, it has been estimated that every year the disease causes the death of 1 million children under 14 yr old1. The mosquito vector of malaria is infected when it ingests mature gametocytes in blood taken from a human carrier of the disease. Development of the parasite continues in the mosquito and culminates with the sporozoite stage, which initiates a new infection when injected by the mosquito into a further human host. Research on P. falciparum sporozoites has been severely limited by a general lack of availability of suitable patients with gametocytes. It was hoped that the recently developed continuous cultivation of P. falciparum2 would solve this, as gametocytes are often produced during cultivation. However, we and others soon found that these gametocytes failed to mature in culture3,4, or at best did so only rarely and unpredictably5–7. We report here that addition of hypoxanthine to the culture medium permits the production of mature, infectious P. falciparum gametocytes on a regular basis.
TL;DR: In this article, it was shown that the loop functions remain multiplicatively renormalizable even if the curves have any finite number of cusps (points of non-differentiability) or cross points (point of self-intersection).
Abstract: It is shown that the vacuum expectation values $W({C}_{1},\ensuremath{\cdots},{C}_{n})$ of products of the traces of the path-ordered phase factors $P\mathrm{exp}[ig\ensuremath{\oint}\ensuremath{\int}{{C}_{i}}^{}{\mathit{A}}_{\ensuremath{\mu}}(x)d{x}^{\ensuremath{\mu}}]$ are multiplicatively renormalizable in all orders of perturbation theory. Here ${\mathit{A}}_{\ensuremath{\mu}}(x)$ are the vector gauge field matrices in the non-Abelian gauge theory with gauge group $\mathrm{U}(N)$ or $\mathrm{SU}(N)$, and ${C}_{i}$ are loops (closed paths). When the loops are smooth (i.e., differentiable) and simple (i.e., non-self-intersecting), it has been shown that the generally divergent loop functions $W$ become finite functions $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}$ when expressed in terms of the renormalized coupling constant and multiplied by the factors ${e}^{\ensuremath{-}KL({C}_{i})}$, where $K$ is linearly divergent and $L({C}_{i})$ is the length of ${C}_{i}$. It is proved here that the loop functions remain multiplicatively renormalizable even if the curves have any finite number of cusps (points of nondifferentiability) or cross points (points of self-intersection). If ${C}_{\ensuremath{\gamma}}$ is a loop which is smooth and simple except for a single cusp of angle $\ensuremath{\gamma}$, then ${W}_{R}({C}_{\ensuremath{\gamma}})=Z(\ensuremath{\gamma})\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}({C}_{\ensuremath{\gamma}})$ is finite for a suitable renormalization factor $Z(\ensuremath{\gamma})$ which depends on $\ensuremath{\gamma}$ but on no other characteristic of ${C}_{\ensuremath{\gamma}}$. This statement is made precise by introducing a regularization, or via a loop-integrand subtraction scheme specified by a normalization condition ${W}_{R}({\overline{C}}_{\ensuremath{\gamma}})=1$ for an arbitrary but fixed loop ${\overline{C}}_{\ensuremath{\gamma}}$. Next, if ${C}_{\ensuremath{\beta}}$ is a loop which is smooth and simple except for a cross point of angles $\ensuremath{\beta}$, then $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}({C}_{\ensuremath{\beta}})$ must be renormalized together with the loop functions of associated sets ${{S}^{i}}_{\ensuremath{\beta}}={{{C}^{i}}_{1},\ensuremath{\cdots},{{C}^{i}}_{\mathrm{pi}}}$ ($i=2,\ensuremath{\cdots},I$) of loops ${{C}^{i}}_{q}$ which coincide with certain parts of ${C}_{\ensuremath{\beta}}\ensuremath{\equiv}{{C}_{1}}^{1}$. Then ${W}_{R}({{S}^{i}}_{\ensuremath{\beta}})={Z}^{\mathrm{ij}}(\ensuremath{\beta})\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}({{S}^{j}}_{\ensuremath{\beta}})$ is finite for a suitable matrix ${Z}^{\mathrm{ij}}(\ensuremath{\beta})$. Finally, for a loop with $r$ cross points of angles ${\ensuremath{\beta}}_{1},\ensuremath{\cdots},{\ensuremath{\beta}}_{r}$ and $s$ cusps of angles ${\ensuremath{\gamma}}_{1},\ensuremath{\cdots},{\ensuremath{\gamma}}_{s}$, the corresponding renormalization matrices factorize locally as ${Z}^{{i}_{1}{j}_{1}}({\ensuremath{\beta}}_{1})\ensuremath{\cdots}{Z}^{{i}_{r}{j}_{r}}({\ensuremath{\beta}}_{r})Z({\ensuremath{\gamma}}_{1})\ensuremath{\cdots}Z({\ensuremath{\gamma}}_{s})$.
TL;DR: In this correspondence, an operator is derived that finds the best oriented plane at each point in the image, which complements other approaches that are either interactive or heuristic extensions of 2-D techniques.
Abstract: Modern scanning techniques, such as computed tomography, have begun to produce true three-dimensional imagery of internal structures. The first stage in finding structure in these images, like that for standard two-dimensional images, is to evaluate a local edge operator over the image. If an edge segment in two dimensions is modeled as an oriented unit line segment that separates unit squares (i.e., pixels) of different intensities, then a three-dimensional edge segment is an oriented unit plane that separates unit volumes (i.e., voxels) of different intensities. In this correspondence we derive an operator that finds the best oriented plane at each point in the image. This operator, which is based directly on the 3-D problem, complements other approaches that are either interactive or heuristic extensions of 2-D techniques.
TL;DR: Apparent motion was used as a probe to test the hypothesis that perceptual framing is correlated to the phase of the alpha rhythm, and the probability of perceived simultaneity was maximal for the positivephase of the occipital alpha cycle.
TL;DR: This article reviewed the book "Culture's Consequences: International Differences in Work-Related Values, by Geert Hofstede" and found that "culture's consequences" can explain differences in work-related values.
Abstract: The article reviews the book “Culture's Consequences: International Differences in Work-Related Values,” by Geert Hofstede.
TL;DR: It is reported that LH, Bt2-cAMP, and the cyclic nucleotide phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine, are all capable of interrupting communication in vitro in rat follicle-enclosed cumulus-oocyte complexes, consistent with the possibility that cAMP, transmitted from the cumulus to the oocyte, may be the inhibitor of oocyte maturation in vivo.
TL;DR: In this paper, it was shown that fixed costs of sufficient magnitude assure the existence of a vector of sustainable prices, a set of product prices that make a (natural) monopolist invulnerable against successful entry.
Abstract: This paper shows that (i) fixed costs of sufficient magnitude assure the existence of a vector of sustainable prices for the products of a natural monopolist-prices making him invulnerable against entry; (ii) nevertheless, fixed costs do not constitute barriers to entry; that is, they need not have undesirable welfare consequences; (iii) indeed, in market forms that we call perfectly contestable large fixed costs are completely compatible with many desirable attributes of competitive equilibrium; (iv) sunk costs do, however, constitute barriers to entry; and (v) finally, the profit and welfare consequences of entry barriers are described formally. In this paper it is shown that (i) fixed costs of sufficient magnitude assure the existence of a vector of sustainable prices-a set of product prices that make a (natural) monopolist invulnerable against successful entry; (ii) nevertheless, costs that are truly fixed do not constitute barriers to entry; that is, they do not have the welfare consequences normally attributed to barriers to entry; (iii) indeed, there are markets of a form (which we call perfectly contestable markets, and whose properties may be approximated in practice) in which large fixed costs are completely compatible with many if not most of the desirable attributes of competitive equilibrium; (iv) sunk costs do, however, constitute barriers to entry; and (v) finally, the resource allocation problems that stem from fixed costs are formally identical with those that accompany public goods-both their sources and their character are the same. Thus, the rationale for public supply of public goods may be no different from that pertaining to nationalization of natural monopolies.
TL;DR: The most important factors determining foreign bank growth were (i) the size of interest differentials between U.S. and foreign deposits and loans, (ii) the falling P/E ratios for U. S. bank stocks, (iii) the increased size of (net) foreign direct investment in the United States, (iv) the persistent depreciation in the dollar, and (v) expectations that the International Banking Act of 1978 would have a restrictive affect on foreign bank activity as discussed by the authors.
Abstract: The recent rapid growth of foreign banking activity in the United States has led to major changes in the regulation of foreign banks. This paper seeks to determine the factors causing this growth of foreign banks. Empirical tests were conducted employing quarterly time series data from 1972 through 1979. It is shown that the most important factors determining foreign bank growth were (i) the size of interest differentials between U.S. and foreign deposits and loans, (ii) the falling P/E ratios for U.S. bank stocks, (iii) the increased size of (net) foreign direct investment in the U.S., (iv) the persistent depreciation in the dollar, and (v) expectations that the International Banking Act of 1978 would have a restrictive affect on foreign bank activity in the U.S.
01 Jan 1981
TL;DR: It has become evident that clinical or morphological criteria alone no longer suffice to classify lymphocytic neoplasms and a definition of the subclass of the cells involved, their immunocytochemical characteristics, and their original role in the immune system appears necessary to arrive at more accurate diagnosis, prognosis, and more appropriate treatment for this group of diseases.
Abstract: As is the case in other areas of research where advances in basic science have changed concepts in clinical medicine, it has become evident that clinical or morphological criteria alone no longer suffice to classify lymphocytic neoplasms. A definition of the subclass of the cells involved, their immunocytochemical characteristics, and their original role in the immune system appears necessary to arrive at more accurate diagnosis, prognosis, and more appropriate treatment for this group of diseases.
TL;DR: In this paper, the authors examine how expectations concerning earnings per share effect share price and show that knowledge concerning analyst's forecasts of earnings cannot by itself lead to excess returns, and that much larger excess returns are earned if one is able to determine those stocks for which analysts most underestimate return.
Abstract: It is generally believed that security prices are determined by expectations concerning firm and economic variables. Despite this belief there is very little research examining expectational data. In this paper we examine how expectations concerning earning per share effect share price. We first show that knowledge concerning analyst's forecasts of earnings per share cannot by itself lead to excess returns. Any information contained in the consensus estimate of earnings per share is already included in share price. Investors or managers who buy high growth stocks where high growth is determined by consensus beliefs should not earn an excess return. This is not due to earnings having no effect upon share price since knowledge of actual earnings leads to excess return. Much larger excess returns are earned if one is able to determine those stocks for which analysts most underestimate return. Finally, the largest returns can be earned by knowing which stocks for which analysts will make the greatest revision in their estimates. This pattern of results suggests that share price is affected by expectations about earnings per share. Given any degree of forecasting ability managers can obtain best results by acting on the differences between their forecasts and concensus forecasts.
01 Apr 1981
TL;DR: In this article, a list of the best book collections and completed collections can be found and the soft file of the book can be read and then download the book and get it.
Abstract: Downloading the book in this website lists can give you more advantages. It will show you the best book collections and completed collections. So many books can be found in this website. So, this is not only this linear systems fourier transforms and optics. However, this book is referred to read because it is an inspiring book to give you more chance to get experiences and also thoughts. This is simple, read the soft file of the book and you get it.
TL;DR: The subrenal capsule model appears to be somewhat more sensitive to drugs than the subcutaneous model and may provide certain advantages for initial panel testing, and some generalizations appear to be emerging.
TL;DR: It is evident that the independent experiences of these hand surgery units in three completely different parts of the world are remarkable similar, but differences are minor compared with the common pattern of experience that clearly exists and upon which conclusions can be based for formulating some general guidelines.
TL;DR: In this paper, the equilibrium distribution is determined directly, without reference to the artificial time, by a stationary condition which is an eigenfunction equation in the euclidean Hilbert space.
TL;DR: It is concluded that naloxone may be useful for the treatment of spinal cord injury and had striking preservation of sensory function and somatosensory evoked potentials at 24 hours after injury.
Abstract: ✓ The effect of naloxone on blood flow and somatosensory evoked potentials was studied in cats subjected to 400 gm-cm contusion injuries of the thoracic spinal cord. Eight cats were treated with 10 mg/kg naloxone 45 to 60 minutes after injury, 11 cats were given 10 ml of saline instead of naloxone, and six cats were neither injured nor treated. Hydrogen clearance was used to measure blood flow in the lateral white columns at the contusion site. Naloxone, given intravenously, significantly improved the blood flow rates in the lateral column white matter. At 2 hours after injury, the mean blood flow in the saline-treated cats fell to 50% (p 0.50) in naloxone-treated cats, and 12% (p > 0.50) in uninjured cats. At the 3rd hour after injury, the respective flows fell 47% (p 0.50), and increased 15% (p > 0.50) of the preinjury flow rates. The naloxone-treated cats had striking preservation of sensory function and somatosensory ev...
TL;DR: It is suggested that intracellular, but not extracellular, calcium plays an obligatory role in the responses of neutrophils to a variety of soluble and insoluble stimuli.
TL;DR: From the data one can infer that the SMR plays a role in "language" aspects of speech (in word finding, in a mechanism facilitating the emission of propositional over "automatic" speech), and also in the "motor" aspect of speech emission (including rhythm control and the control of phonation and articulation).
TL;DR: A repeat-purchase diffusion model is developed, incorporating the effect of marketing variables-detailing force effects in particular-as well as a word-of-mouth effect to forecast and control the rate of sales for a new product.
Abstract: This paper develops a model and an associated estimation procedure to forecast and control the rate of sales for a new product. A repeat-purchase diffusion model is developed, incorporating the effect of marketing variables-detailing force effects in particular-as well as a word-of-mouth effect. Bayesian estimation, with priors developed from past products is used to estimate and update the parameters of the model. The procedure is used to develop marketing policies for new product introduction.
TL;DR: Two cases of melanotic neuroectodermal tumor of infancy were examined by electron microscopy and an extensive review of the literature was performed, and morphologic data were consistent with the concept that the tumor arises from neural crest cells.
Abstract: Two cases of melanotic neuroectodermal tumor of infancy were examined by electron microscopy and an extensive review of the literature was performed. Ultrastructural examination revealed several features not previously described for this lesion. Three different types of melanin granule formation were observed, many cells had a single cilium, and cell junctions of the "close" or "modified-tight" type were seen, but no desmosomes were found. The morphologic data were consistent with the concept that the tumor arises from neural crest cells. The review of the literature indicated that there have been 158 reported cases of this lesion, including the two reported here. There were five cases of malignant tumor reported for a rate of 3.2%. This rate of malignancy is very high in view of the fact that the tumor has been described as universally benign. The significance of this finding is discussed with regard to melanin-producing lesions of the oral cavity.