Showing papers by "Massachusetts Institute of Technology published in 1977"
TL;DR: In this article, the authors predict that corporate borrowing is inversely related to the proportion of market value accounted for by real options and rationalize other aspects of corporate borrowing behavior, such as the practice of matching maturities of assets and debt liabilities.
12,521 citations
TL;DR: This article examined postwar patterns in macroeconomic policies and outcomes associated with left-and right-wing governments in capitalist democracies and concluded that the objective economic interests as well as the subjective preferences of lower income and occupational status groups are best served by a relatively low unemployment-high inflation macroeconomic configuration, whereas a comparatively high unemployment-low inflation configuration is compatible with the interests and preferences of upper income and occupation status groups.
Abstract: This study examines postwar patterns in macroeconomic policies and outcomes associated with left-and right-wing governments in capitalist democracies. It argues that the objective economic interests as well as the subjective preferences of lower income and occupational status groups are best served by a relatively low unemployment-high inflation macroeconomic configuration, whereas a comparatively high unemployment-low inflation configuration is compatible with the interests and preferences of upper income and occupational status groups. Highly aggregated data on unemployment and inflation outcomes in relation to the political orientation of governments in 12 West European and North American nations are analyzed revealing a low unemployment-high inflation configuration in nations regularly governed by the Left and a high unemployment-low inflation pattern in political systems dominated by center and rightist parties. Finally, time-series analyses of quarterly postwar unemployment data for the United States and Great Britain suggests that the unemployment rate has been driven downward by Democratic and Labour administrations and upward by Republican and Conservative governments. The general conclusion is that governments pursue macroeconomic policies broadly in accordance with the objective economic interests and subjective preferences of their class-defined core political constituencies.
2,911 citations
TL;DR: A simple and sensitive method for detecting, sizing and mapping RNA transcripts from viral or cloned DNAs has been developed and used to examine the cytoplasmic transcripts produced during the early phase of adenovirus 2 (Ad2) infection of HeLa cells.
2,367 citations
TL;DR: In this paper, a formula is derived to evaluate the cost of issuing a guarantee of a loan by a third party, and the method used is to demonstrate an isomorphic correspondence between loan guarantees and common stock put options and then to use the well developed theory of option pricing to derive the formula.
Abstract: It is not uncommon in the arrangement of a loan to include as part of the financial package a guarantee of the loan by a third party. Examples are guarantees by a parent company of loans made to its subsidiaries or government guarantees of loans made to private corporations. Also included would be guarantees of bank deposits by the Federal Deposit Insurance Corporation. As with other forms of insurance, the issuing of a guarantee imposes a liability or cost on the guarantor. In this paper, a formula is derived to evaluate this cost. The method used is to demonstrate an isomorphic correspondence between loan guarantees and common stock put options, and then to use the well developed theory of option pricing to derive the formula.
1,983 citations
TL;DR: Four segments of viral RNA may be joined together during the synthesis of mature hexon mRNA, a model is presented for adenovirus late mRNA synthesis that involves multiple splicing during maturation of a larger precursor nuclear RNA.
Abstract: An mRNA fraction coding for hexon polypeptide, the major virion structural protein, was purified by gel electrophoresis from extracts of adenovirus 2-infected cells late in the lytic cycle. The mRNA sequences in this fraction were mapped between 51.7 and 61.3 units on the genome by visualizing RNA-DNA hybrids in the electron microscope. When hybrids of hexon mRNA and single-stranded restriction endonuclease cleavage fragments of viral DNA were visualized in the electron microscope,branched forms were observed in which 160 nucleotides of RNA from the 5' terminus were not hydrogen bonded to the single-stranded DNA. DNA sequences complementary to the RNA sequences in each 5' tail were found by electron microscopy to be located at 17, 20, and 27 units on the same strand as that coding for the body of the hexon mRNA. Thus, four segments of viral RNA may be joined together during the synthesis of mature hexon mRNA. A model is presented for adenovirus late mRNA synthesis that involves multiple splicing during maturation of a larger precursor nuclear RNA.
1,229 citations
Patent•
14 Dec 1977TL;DR: In this paper, a message-to-be-transferred message is enciphered to ciphertext at the encoding terminal by first encoding the message as a number M in a predetermined set, and then raising that number to a first predetermined power (associated with the intended receiver) and finally computing the remainder, or residue, C, when the exponentiated number is divided by the product of two predetermined prime numbers associated with intended receiver.
Abstract: A cryptographic communications system and method. The system includes a communications channel coupled to at least one terminal having an encoding device and to at least one terminal having a decoding device. A message-to-be-transferred is enciphered to ciphertext at the encoding terminal by first encoding the message as a number M in a predetermined set, and then raising that number to a first predetermined power (associated with the intended receiver) and finally computing the remainder, or residue, C, when the exponentiated number is divided by the product of two predetermined prime numbers (associated with the intended receiver). The residue C is the ciphertext. The ciphertext is deciphered to the original message at the decoding terminal in a similar manner by raising the ciphertext to a second predetermined power (associated with the intended receiver), and then computing the residue, M', when the exponentiated ciphertext is divided by the product of the two predetermined prime numbers associated with the intended receiver. The residue M' corresponds to the original encoded message M.
1,129 citations
TL;DR: A test of everyday speech reception is described, in which a listener’s utilization of the linguistic‐situational information of speech is assessed, and is compared with the utilization of acoustic‐phonetic information.
Abstract: This paper describes a test of everyday speech reception, in which a listener’s utilization of the linguistic‐situational information of speech is assessed, and is compared with the utilization of acoustic‐phonetic information. The test items are sentences which are presented in babble‐type noise, and the listener response is the final word in the sentence (the key word) which is always a monosyllabic noun. Two types of sentences are used: high‐predictability items for which the key word is somewhat predictable from the context, and low‐predictability items for which the final word cannot be predicted from the context. Both types are included in several 50‐item forms of the test, which are balanced for intelligibility, key‐word familiarity and predictability, phonetic content, and length. Performance of normally hearing listeners for various signal‐to‐noise ratios shows significantly different functions for low‐ and high‐predictability items. The potential applications of this test, particularly in the assessment of speech reception in the hearing impaired, are discussed.
1,076 citations
TL;DR: A light sensing apparatus is described which employs a GaAsP MOS light-receiving element to which a potential is applied for creating a depletion region.
1,062 citations
TL;DR: The culture lifetime of epidermal cells of newborn humans is increased from 50 to 150 generations by adding to the medium epidermis growth factor, a polypeptide mitogen, which seems to delay senescence of the cells by maintaining them in a state further removed from terminal differentiation.
Abstract: The culture lifetime of epidermal cells of newborn humans is increased from 50 to 150 generations by adding to the medium epidermal growth factor, a polypeptide mitogen. EGF seems to delay senescence of the cells by maintaining them in a state further removed from terminal differentiation. This effect is revealed by a greater ability of the cells to survive subculture and initiate new colonies, but not necessarily by an increased growth rate.
1,047 citations
TL;DR: In this paper, the In and Sn 3d3/2 and 3d5/2 ESCA peaks and the oxygen 1s peak of Sn-doped In2O3 films were compared with those for In 2O3, SnO, Sn2O2, and Sn3O4 powders.
Abstract: The In and Sn 3d3/2 and 3d5/2 ESCA peaks and the oxygen 1s peak of Sn‐doped In2O3 films were compared with those for In2O3 films and In2O3, SnO, SnO2, and Sn3O4 powders. Comparison of as‐grown with sanded surfaces revealed Sn‐rich surface layers in.those films having good optical and transport properties. These experimental fins are interpreted with a schematic energy‐band model and the assumption that film darkening in Sn‐doped In2O3 films is caused by the formation and growth of an Sn3O4‐like second phase in the bulk. Suppression of these phase could be accomplished by higher substrate temperatures, which permit equilibrium conditions to be attained. Sn‐rich phases to migrate to the films surface, and the tine disproportionates to Sn2+ and Sn4+ ions.
973 citations
TL;DR: In this article, the spectra and dominant decay couplings of mesons are calculated in the quark-bag model and shown to be broad, heavy, and usually inelastic in formation processes.
Abstract: The spectra and dominant decay couplings of ${Q}^{2}{\overline{Q}}^{2}$ mesons are presented as calculated in the quark-bag model. Certain known ${0}^{+}$ mesons [$\ensuremath{\epsilon}(700),{S}^{*},\ensuremath{\delta},\ensuremath{\kappa}$] are assigned to the lightest cryptoexotic ${Q}^{2}{\overline{Q}}^{2}$ nonet. The usual quark-model ${0}^{+}$ nonet ($Q\overline{Q} L=1$) must lie higher in mass. All other ${Q}^{2}{\overline{Q}}^{2}$ mesons are predicted to be broad, heavy, and usually inelastic in formation processes. Other ${Q}^{2}{\overline{Q}}^{2}$ states which may be experimentally prominent are discussed.
TL;DR: In the quark bag model, the same gluon-exchange forces which make the proton lighter than the $\ensuremath{\Delta}(1236)$ bind six quarks to form a stable, flavor-singlet (with strangeness of - 2) ${J}^{P}={0}^{+}$ dihyperon ($H$) at 2150 MeV as discussed by the authors.
Abstract: In the quark bag model, the same gluon-exchange forces which make the proton lighter than the $\ensuremath{\Delta}(1236)$ bind six quarks to form a stable, flavor-singlet (with strangeness of - 2) ${J}^{P}={0}^{+}$ dihyperon ($H$) at 2150 MeV. Another isosinglet dihyperon (${H}^{*}$) with ${J}^{P}={1}^{+}$ at 2335 MeV should appear as a bump in $\ensuremath{\Lambda}\ensuremath{\Lambda}$ invariant-mass plots. Production and decay systematics of the $H$ are discussed.
TL;DR: In this paper, a rule-based system for computer-aided circuit analysis, called EL, is presented, which is written in a rule language called ARS, and implemented by ARS as pattern-directed invocation demons monitoring an associative data base.
TL;DR: The afferent connections of the habenular complex in the rat were examined by injecting horseradish peroxidase into discrete portions of theHabenular nuclei by microelectrophoresis.
Abstract: The afferent connections of the habenular complex in the rat were examined by injecting horseradish peroxidase (HRP) into discrete portions of the habenular nuclei by microelectrophoresis.
TL;DR: The development at age 10 of the ability to encode orientation-specific configurational aspects of a face may reflect completion of certain maturational changes in the right cerebral hemisphere.
Abstract: Unlike older children and adults, children of less than about 10 years of age remember photographs of faces presented upside down almost as well as those shown upright and are easily fooled by simple disguises. The development at age 10 of the ability to encode orientation-specific configurational aspects of a face may reflect completion of certain maturational changes in the right cerebral hemisphere.
TL;DR: In this paper, the effects of changes in albedo on rainfall in semi-arid areas were studied and the mechanism by which an increase of albedos reduces the rainfall during conditions of high evaporation was considered.
Abstract: Numerical simulation studies of the effects of changes in albedo on rainfall involve comparisons of semiarid areas, lying at the boundary between a major desert and an adjacent monsoonal region, with areas of the same size located within the monsoonal region itself. The sensitivity of the rainfall to the ground hydrology was determined by performing the albedo simulations with two different evapotranspiration parameterizations, one giving too high evaporation over land and the other giving negligible evaporation over land. The evaporation rate is, in general, found to have as important an effect as changes in albedo. The mechanism by which an increase of albedo reduces the rainfall during conditions of high evaporation is considered.
TL;DR: Rapid, dramatic, and reversible increases in histone acetylation in the presence of n-butyrate are described.
Abstract: LEDER and Leder1 have reported that low concentrations of n-butyrate cause Friend erythroleukaemia cells to begin globin synthesis. Apparently n-butyrate can reverse that part of viral transformation which prevents the expression of differentiation in these cells. Prasad and Sinha2 have summarised the effects of n-butyrate on neuroblastoma, HeLa, and other cell types. They and others3–10 have seen reversible inhibition of proliferation, decrease of DNA content, morphological modifications, and increases in the production of specific enzymes, such as adenylate cyclase, alkaline phosphatase, and a sialyltransferase. The present paper describes rapid, dramatic, and reversible increases in histone acetylation in the presence of n-butyrate.
TL;DR: The gradient space, popularized by Huffman and Mackworth in a slightly different context, is a helpful tool in the development of new methods for exploiting three-dimensional shape information in image intensities.
TL;DR: In this article, the fundamental mechanisms of sliding wear postulated by the delamination theory of wear are reviewed in terms of the experimental and analytical work done to date at MIT and a hypothesis (without experimental verification) is advanced for the formation of the Beilby layer.
TL;DR: This paper provides an introduction to the abstraction mechanisms in CLU by means of programming examples, and it is shown how CLU programs may be written to use and implement abstractions.
Abstract: CLU is a new programming language designed to support the use of abstractions in program construction. Work in programming methodology has led to the realization that three kinds of abstractions—procedural, control, and especially data abstractions—are useful in the programming process. Of these, only the procedural abstraction is supported well by conventional languages, through the procedure or subroutine. CLU provides, in addition to procedures, novel linguistic mechanisms that support the use of data and control abstractions. This paper provides an introduction to the abstraction mechanisms in CLU. By means of programming examples, the utility of the three kinds of abstractions in program construction is illustrated, and it is shown how CLU programs may be written to use and implement abstractions. The CLU library, which permits incremental program development with complete type checking performed at compile time, is also discussed.
TL;DR: A new global convergence theorem for noncontinuous iteration algorithms is developed that converges, with successive updates of the routing tables, to the minimum average delay over all routing assignments.
Abstract: An algorithm is defined for establishing routing tables in the individual nodes of a data network. The routing table at a node i specifies, for each other node j , what fraction of the traffic destined for node j should leave node i on each of the links emanating from node i . The algorithm is applied independently at each node and successively updates the routing table at that node based on information communicated between adjacent nodes about the marginal delay to each destination. For stationary input traffic statistics, the average delay per message through the network converges, with successive updates of the routing tables, to the minimum average delay over all routing assignments. The algorithm has the additional property that the traffic to each destination is guaranteed to be loop free at each iteration of the algorithm. In addition, a new global convergence theorem for noncontinuous iteration algorithms is developed.
TL;DR: A survey of U.S. east coast estuaries confirms that large-scale rapid removal of iron from river water is a general phenomenon during estuarine mixing as discussed by the authors.
TL;DR: Translocatable drug-resistance elements are useful in isolation of mutants, in the construction of strains and other genetic manipulations (even when selection is difficult or impossible), in localized mutagenesis, in chromosomal mapping, in construction of Hfr strains with known origin and direction of chromosome transfer, in complementation tests.
01 Jan 1977
TL;DR: In this article, the authors measured the volatile yields of lignite and bituminous coal at high temperatures under rapid heating conditions and found that volatile yields increase significantly with temperature, from about 30% (d.a.f.) at 1260 K and 20ms to about 63% at 2100 K and 25ms.
Abstract: Devolatilization of a lignite and a bituminous coal was studied at high temperatures under rapid heating conditions. Devolatilization rates were measured in a flow furnace designed to yield heating rates of 10 4 –2×10 5 K/s, temperatures of 1000–2100 K time resolution down to a few milliseconds product quenching rates of 10 6 K/s and good particle collection efficiencies. The volatile yields in this study were determined both by difference in the weights of coal fed and char collected and by use of ash as a tracer. Volatile yields of both coals increase significantly with temperature, from about 30% (d.a.f.) at 1260 K and 20ms to about 63% at 2100 K and 25ms. The maximum volatile yields were significantly in excess of the 46% value given by the ASTM proximate volatile test. The yields are even higher when an estimated correction is introduced for condensed material produced during devolatilization that is collected with the char residue. Correlation of the pyrolysis kinetics with a single Arrhenius type rate expression, assuming first order behavior with respect to volatile matter remaining in the char, yielded an apparent frequency factor of about 6.6×10 4 s −1 and an apparent activation energy of about 25 kcal/mole. These results are consistent with an extrapolation to higher temperatures of data previously reported in the literature for similar coals. An empirical model based on two competing overall reactions gave a better fit of the data over all of the conditions of the present study than was obtained using the single-reaction model.
TL;DR: The current status is summarized of investigations of the Martian atmosphere, in which use was made of the mass spectrometers that function as the analytical component of the molecular analysis experiments on the two Viking landers.
Abstract: The current status is summarized of investigations of the composition of the Martian atmosphere, in which use was made of the mass spectrometers that function as the analytical component of the molecular analysis experiments on the two Viking landers. The following points seem well established: N2, Ar-40, Ne, Kr, Xe, and the primordial isotope of Ar are present. The present atmosphere of Mars represents only a small fraction of the total amount of volatiles outgassed by the planet, so that high surface pressure and abundant water may have been present. The noble gases in the Martian atmosphere exhibit a relative abundance pattern similar to that in the earth's atmosphere and (except for Xe) to that in the primordial component of meteorites. The existence of a 'planetary component' is thus proven, supporting the arguments of those who favor a fractionation of noble gases prior to the formation of the planets. In spite of these similarities, the isotopic ratios of nitrogen, argon, and xenon indicate that the histories of the Martian and the earth's atmospheres have been very different.
TL;DR: In this article, the authors discuss how solutions to field equations, treated as classical, c-number nonlinear differential equations, expose unexpected states in the quantal Hilbert space with novel quantum numbers which arise from topological properties of the classical field configuration or from the mixing of internal and space-time symmetries.
Abstract: Recent researches have shown that it is possible to obtain information about the physical content of nontrivial quantum field theories by semiclassical methods. This article reviews some of these investigations. We discuss how solutions to field equations, treated as classical, c-number nonlinear differential equations, expose unexpected states in the quantal Hilbert space with novel quantum numbers which arise from topological properties of the classical field configuration or from the mixing of internal and space-time symmetries. Also imaginary-time, c-number solutions are reviewed. It is shown that they provide nonperturbative information about the vacuum sector of the quantum theory.
TL;DR: This paper provides an introduction to the abstraction mechanisms in CLU and illustrates the utility of the three kinds of abstractions in program construction and shows how CLU programs may be written to use and implement abstractions.
Abstract: CLU is a new programming language designed to support the use of abstractions in program construction. Work in programming methodology has led to the realization that three kinds of abstractions, procedural, control, and especially data abstractions, are useful in the programming process. Of these, only the procedural abstraction is supported well by conventional languages, through the procedure or subroutine. CLU provides, in addition to procedures, novel linguistic mechanisms that support the use of data and control abstractions.This paper provides an introduction to the abstraction mechanisms in CLU. By means of programming examples, we illustrate the utility of the three kinds of abstractions in program construction and show how CLU programs may be written to use and implement abstractions. We also discuss the CLU library, which permits incremental program development with complete type-checking performed at compile-time.
TL;DR: A total of four Martian samples, one surface and one subsurface sample at each of the two Viking landing sites, Chryse Planitia and Utopia Planitia, have been analyzed for organic compounds by a gas chromatograph-mass spectrometer.
Abstract: A total of four Martian samples, one surface and one subsurface sample at each of the two Viking landing sites, Chryse Planitia and Utopia Planitia, have been analyzed for organic compounds by a gas chromatograph-mass spectrometer. In none of these experiments could organic material of Martian origin be detected at detection limits generally of the order of parts per billion and for a few substances closer to parts per million. The evolution of water and carbon dioxide, but not of other inorganic gases, was observed upon heating the sample to temperatures of up to 500 C. The absence of organic compounds seems to preclude their production on the planet at rates that exceed the rate of their destruction. It also makes it unlikely that living systems that behave in a manner similar to terrestrial biota exist, at least at the two Viking landing sites.
TL;DR: The properties of the cornified envelopes (insolubility in detergent and reducing agents, and solubility following proteolytic digestion) are readily explained by a structure consisting of a cross-linked protein lattice.
TL;DR: Three aspects of terminal differentiation of the epidermal keratinocyte have been studied in cell culture—the development of detergent-insoluble cytoplasmic filaments, the formation of a cornified cell envelope and the destruction of the cell nucleus.