Showing papers by "Rutgers University published in 1985"
TL;DR: In this article, a new isotopy invariant of oriented links of tamely embedded circles in 3-space is presented, where the image of the link is a union of transversely intersecting immersed curves, each provided with an orientation, and undercrossings are indicated by broken lines.
Abstract: The purpose of this note is to announce a new isotopy invariant of oriented links of tamely embedded circles in 3-space. We represent links by plane projections, using the customary conventions that the image of the link is a union of transversely intersecting immersed curves, each provided with an orientation, and undercrossings are indicated by broken lines. Following Conway [6], we use the symbols L+, Lo, L_ to denote links having plane projections which agree except in a small disk, and inside that disk are represented by the pictures of Figure 1. Conway showed that the one-variable Alexander polynomials of L+, Lo, L_ (when suitably normalized) satisfy the relation
1,225 citations
TL;DR: In this article, the authors applied substrate-electron acceptor combinations and specific metabolic inhibitors to anoxic saltmarsh sediment spiked with mercuric ions (Hg2+) in an effort to identify, by a direct approach, the microorganisms responsible for the synthesis of hazardous monomethylmercury.
Abstract: Substrate-electron acceptor combinations and specific metabolic inhibitors were applied to anoxic saltmarsh sediment spiked with mercuric ions (Hg2+) in an effort to identify, by a direct approach, the microorganisms responsible for the synthesis of hazardous monomethylmercury. 2-Bromoethane sulfonate (30 mM), a specific inhibitor of methanogens, increased monomethylmercury synthesis, whereas sodium molybdate (20 mM), a specific inhibitor of sulfate reducers, decreased Hg2+ methylation by more than 95%. Anaerobic enrichment and isolation procedures yielded a Desulfovibrio desulfuricans culture that vigorously methylated Hg2+ in culture solution and also in samples of presterilized sediment. The Hg2+ methylation activity of sulfate reducers is fully expressed only when sulfate is limiting and fermentable organic substrates are available. To date, sulfate reducers have not been suspected of Hg2+ methylation. Identification of these bacteria as the principal methylators of Hg2+ in anoxic sediments raises questions about the environmental relevance of previous pure culture-based methylation work.
1,195 citations
TL;DR: In this article, the authors identify and analyze three constructs basic to the study of gender relations, i.e., boundaries, negotiation and domination, and consciousness, and argue that this conceptual framework produces a more sensitive and complex set of analytical tools for understanding gender relations.
Abstract: This paper identifies and analyzes three constructs basic to the study of gender relations–boundaries, negotiation and domination, and consciousness. The concept of boundaries describes the complex structures–physical, social, ideological, and psychological–which establish differences and commonalities between women arid men, among women, and among men. The reciprocal processes of negotiation and domination elucidate the ways in which women and men act to support and/or challenge the existing system of gender relations. While domination describes systems of control and coercion, negotiation addresses the ways women and men bargain for privileges and resources. Consciousness assumes various forms ranging from gender awareness to feminist/anti-feminist consciousness, and is conceived as a process which develops dialectically in the social relations of the sexes. We argue that this conceptual framework produces a more sensitive and complex set of analytical tools for understanding gender relations.
320 citations
Journal Article•
TL;DR: D dopamine plays an important role in the changes mediated by the administration of methamphetamine in both the dopaminergic and serotonergic systems, and the ability of a single administrations of methamphetamine to depress tryptophan hydroxylase was also dependent on catecholamine synthesis.
Abstract: Multiple administrations of high doses of methamphetamine to rats cause long-term depression of both dopamine and serotonin synthesis. Coadministration of the catecholamine synthesis inhibitor, alpha-methyl-p-tyrosine, antagonizes this effect of methamphetamine on both neurotransmitter systems. However, when catecholamine synthesis was maintained by the administration of L-dopa and the peripheral decarboxylase inhibitor R04-4602, alpha-methyl-p-tyrosine no longer prevented the effects of methamphetamine on either dopamine or serotonin synthesis. In addition, the administration of the specific dopamine uptake blocker, amfonelic acid, significantly attenuated the changes in the serotonin synthesizing enzyme, tryptophan hydroxylase, resulting from multiple high doses of methamphetamine. The ability of a single administration of methamphetamine to depress tryptophan hydroxylase was also dependent on catecholamine synthesis. These results suggest that dopamine plays an important role in the changes mediated by the administration of methamphetamine in both the dopaminergic and serotonergic systems.
311 citations
TL;DR: Questions are raised regarding the robustness of the Type A hypothesis in its present form and the validity of procedures used to assess behavior patterns in the Multiple Risk Factor Intervention Trial.
Abstract: Behavior pattern was assessed by interview for 3,110 men at eight centers in the Multiple Risk Factor Intervention Trial (1973-1976). The Type A pattern was not significantly associated with risk of first major coronary events (coronary death and definite nonfatal myocardial infarction) after a mean follow-up of 7.1 years. Crude relative risks for Types A1-A2 versus X-B were 1.08 in usual care, 0.82 in special intervention, and 0.92 overall. Adjustment for age, blood pressure, cigarette smoking, serum cholesterol, consumption of alcohol, and educational attainment yielded relative risks of 0.99 in usual care, 0.81 in special intervention, and 0.87 overall (95% confidence interval = 0.59-1.28). The Jenkins Activity Survey Type A score, obtained for 12,772 men at all 22 centers, was also not significantly associated with risk of first major coronary events. Overall, crude risks in the lowest (Type B) through highest (Type A) quintiles of the score's distribution were 5.0%, 4.4%, 4.0%, 4.3%, and 4.1%, respectively. The proportional hazards regression coefficient, adjusted for the variables listed above, was -0.006 (95% confidence interval = -0.015-0.003). These results raise questions regarding the robustness of the Type A hypothesis in its present form. Further studies are needed to investigate these questions and to evaluate the validity of procedures used to assess behavior patterns.
290 citations
TL;DR: The data lend support to the concept that MPTP-induced neurotoxicity may be due to the detrimental actions of enzymatically formed MPP+ on mitochondrial function and demonstrate that a mitochondrial toxin, administered stereotaxically, is extremely neurotoxic.
290 citations
TL;DR: Starting from an arbitrary isometry of an arbitrary even lattice, twisted and shifted vertex operators are introduced and under commutators, these operators provide realizations of twisted affine Lie algebras.
Abstract: Starting from an arbitrary isometry of an arbitrary even lattice, twisted and shifted vertex operators are introduced. Under commutators, these operators provide realizations of twisted affine Lie algebras. This construction, generalizing a number of known ones, is based on a self-contained “calculus.”
282 citations
TL;DR: Research on knowledge representation in artificial intelligence provides a wealth of relevant techniques that can be incorporated into specification languages.
Abstract: Specification of many kinds of knowledge about the world is essential to requirements engineering. Research on knowledge representation in artificial intelligence provides a wealth of relevant techniques that can be incorporated into specification languages.
274 citations
TL;DR: Pellegrini and Galda as discussed by the authors found that role playing significantly improved comprehension of story and story retelling ability, when role playing stories, active involvement and peer interaction contributed to children's increased performance.
Abstract: The Elementary School Journal Volume 85, Number 5 ? 1985 by The University of Chicago. All rights reserved. 0013-5984/85/8505-0006$01.00 Educators recognize that young children who have stories read to them develop more sophisticated language structures, accumulate more background information, and have more interest in learning to read (Bower 1976; Chomsky 1972; Cohen 1968; Durkin 1966). In addition, active participation in literary experiences enhances the development of comprehension, oral language, and a sense of story structure (Blank & Sheldon 1971; Bower 1976). For example, Brown's research (1975) suggests that children's story comprehension is facilitated when they are involved actively in the reconstruction of a story. She defines reconstruction as children's thinking about the individual story events and arranging pictures of the story in sequential order. By mentally reconstructing the events themselves and arranging pictures, children build an internal representation of the story. In another study, Pellegrini and Galda tested the effects of varying modes of active involvement in story reconstruction on comprehension. Role playing significantly improved comprehension of story and story retelling ability. According to Pellegrini and Galda, when role playing stories, active involvement and peer interaction contributed to the children's increased performance.
260 citations
TL;DR: In this article, the authors studied the asymptotic behavior of nonstationary Markov chains and proved the convergence of the annealing algorithm in Monte Carlo simulations, and provided a rigorous procedure for choosing the optimal schedule.
Abstract: We study the asymptotic behavior as timet → + ∞ of certain nonstationary Markov chains, and prove the convergence of the annealing algorithm in Monte Carlo simulations. We find that in the limitt → + ∞, a nonstationary Markov chain may exhibit “phase transitions.” Nonstationary Markov chains in general, and the annealing algorithm in particular, lead to biased estimators for the expectation values of the process. We compute the leading terms in the bias and the variance of the sample-means estimator. We find that the annealing algorithm converges if the temperatureT(t) goes to zero no faster thanC/log(t/t0) ast→+∞, with a computable constantC andt0 the initial time. The bias and the variance of the sample-means estimator in the annealing algorithm go to zero likeO(t−1+e) for some 0⩽e<1, with e=0 only in very special circumstances. Our results concerning the convergence of the annealing algorithm, and the rate of convergence to zero of the bias and the variance of the sample-means estimator, provide a rigorous procedure for choosing the optimal “annealing schedule.” This optimal choice reflects the competition between two physical effects: (a) The “adiabatic” effect, whereby if the temperature is loweredtoo abruptly the system may end up not in a ground state but in a nearby metastable state, and (b) the “super-cooling” effect, whereby if the temperature is loweredtoo slowly the system will indeed approach the ground state(s) but may do so extremely slowly.
259 citations
TL;DR: In this article, a revised geochronology based upon a best fit to selected high temperature radiometric dates on a number of identified magnetic polarity chrons (within the late Cretaceous, Paleogene and Neogene) which minimizes apparent acceleration in sea-floor spreading is presented.
Abstract: Summary We present a revised Paleogene geochronology based upon a best fit to selected high temperature radiometric dates on a number of identified magnetic polarity chrons (within the late Cretaceous, Paleogene and Neogene) which minimizes apparent accelerations in sea-floor spreading. An assessment of first order correlations of calcareous plankton biostratigraphic datum events to magnetic polarity stratigraphy yields the following estimated magnetobiochronology of major chronostratigraphic boundaries: Cretaceous-Tertiary boundary (Chron C29R), 66.4 Ma; Paleocene-Eocene (Chron C24R), 57.8 Ma; Eocene-Oligocene (Chron C13R), 36.6 Ma; Oligocene-Miocene (Chron C6CN), 23.7 Ma. The Eocene is seen to have expanded chronologically (~ 21 m.y.) at the expense of the Paleocene (~ 9 m.y.) and is indeed the longest of the Cenozoic epochs. In addition, magnetobiostratigraphic correlations require adjustments in apparent correlations with standard marine stage boundaries in some cases (particularly in the Oligocene). Finally, we present a correlation between standard Paleogene marine and terrestrial stratigraphies.
TL;DR: The results of this study suggest two possible mechanisms for deposition of collagen in keloid lesions in vivo: first, the growth of the lesions may result from a localized loss of control of the extracellular matrix production by fibroblasts; secondly, reduced degradation of the newly synthesized procollagen polypeptides may contribute to collagen deposition in some keloids.
TL;DR: An exception-handling facility suitable for languages used to implement database-intensive information systems is presented, and solutions are proposed to a range of problems, including sharing and computing with exceptional information, exception handling by users, the logic of constraints with exceptions, and implementation issues.
Abstract: An exception-handling facility suitable for languages used to implement database-intensive information systems is presented Such a mechanism facilitates the development and maintenance of more flexible software systems by supporting the abstraction of details concerning special or abnormal occurrences The type constraints imposed by the schema as well as various semantic integrity assertions are considered to be normalcy conditions, and the key contribution of this work is to allow exceptions to these constraints to persist To achieve this, solutions are proposed to a range of problems, including sharing and computing with exceptional information, exception handling by users, the logic of constraints with exceptions, and implementation issues The use of exception handling in dealing with null values, estimates, and measurement is also illustrated
TL;DR: On considere le probleme de l'unicite pour les solutions positives du Dirichlet non lineaire Δu+f(u,|x|) = 0 dans Ω, u/ ∂Ω = 0, Ω est une boule ou un anneau de R n and f≥0 est superlineaire en u and satisfaisait f(0, |x|)=0 as mentioned in this paper.
Abstract: On considere le probleme de l'unicite pour les solutions positives du probleme de Dirichlet non lineaire Δu+f(u,|x|)=0 dans Ω, u/ ∂Ω =0, Ω est une boule ou un anneau de R n et f≥0 est superlineaire en u et satisfaisait f(0,|x|)=0
TL;DR: In this article, a contact function for two arbitrary ellipsoids is derived, where the numerical value of the contact function is less than 1 if they overlap, and greater than 2 if they do not.
Proceedings Article•
18 Aug 1985TL;DR: In this paper, the authors define Learning Apprentice Systems as the class of interactive knowledge-based consultants that directly assimilate new knowledge by observing and analyzing the problem solving steps contributed by their users through their normal use of the system.
Abstract: It is by now well-recognised that a major impediment to developing know ledge-based systems is the knowledge acquisition bottleneck the task of building up a complete enough and correct enough knowledge base to provide high-level performance. This paper proposes a new class of knowledge-based systems designed to address this knowledge-acquisition bottleneck by incorporating a learning component to acquire new knowledge through experience. In particular, we define Learning Apprentice Systems as the class of interactive knowledge-based consultants that directly assimilate new knowledge by observing and analyzing the problem solving steps contributed by their users through their normal use of the system. This paper describes a specific Learning Apprentice System, called LEAP, which is presently being developed in the domain of VLSI design We also discuss design issues for Learning Apprentice Systems more generally, as well as restrictions on the generality of our current approach.
TL;DR: Although there was some indication of backward associations, the evidence was generally weak, and statistical evaluations did not reach conventional significance levels, these results may identify some key features of interspecies differences and contribute to analyses of serial learning in animals.
Abstract: In Experiment 1 six monkeys were tested with discriminative relations that were backward relative to their training in a 0-second conditional (“symbolic”) matching procedure Although there was some indication of backward associations, the evidence was generally weak, and statistical evaluations did not reach conventional significance levels Unlike children, who show backward associations to the point of symmetry, monkeys and pigeons display at best only weak and transient backward associations In Experiment 2 associative transitivity was assessed across two sets of conditional matching tasks All four monkeys tested demonstrated strong transitivity In contrast, in Experiment 3 there was no evidence of transitivity in three pigeons tested under conditions closely comparable to those of Experiment 2 These results may identify some key features of interspecies differences and contribute to analyses of serial learning in animals
01 Jan 1985
Journal Article•
TL;DR: Results further establish the role of P-450 isozymes in the metabolism of nitrosamines and indicate that LM3a is apparently responsible for the increased N-nitrosodimethylamine metabolism associated with ethanol treatment.
Abstract: The metabolism of nitrosamines by microsomal cytochrome P-450 (P-450) isozymes was studied in a reconstituted monooxygenase system. P-450 LM2, LM3a, LM3b and LM3c, LM4, and LM6 were purified, respectively, from the livers of phenobarbital-treated, ethanol-treated, untreated, isosafrole-treated, and imidazole-treated rabbits. Of these isozymes, LM3a had the highest N-nitrosodimethylamine demethylase (NDMAd) activity with a Km of 2.9 mM and Vmax of 9.3 nmol/min/nmol. LM2, LM4, and LM6 exhibited NDMAd activity only at high N-nitrosodimethylamine concentrations, and isozymes LM3b and LM3c had poor activity even at the highest substrate concentrations examined. LM2, however, was more active than LM3a in the metabolism of N-nitrosomethylaniline. With each isozyme (LM3a or LM4), only one Km for NDMAd was observed, whereas with rabbit liver microsomes, multiple Km of 0.07, 0.27, and 36.8 mM were obtained. P-450 isozymes also catalyzed the denitrosation of nitrosamines at rates comparable to or lower than the demethylation, and the ratio of these two reactions was different with different nitrosamines. 2-Phenylethylamine and 3-amino-1,2,4-triazole, which were believed previously to affect NDMAd by mechanisms independent of P-450, were shown to be potent inhibitors of P-450-dependent NDMAd. These results further establish the role of P-450 isozymes in the metabolism of nitrosamines and indicate that LM3a is apparently responsible for the increased N-nitrosodimethylamine metabolism associated with ethanol treatment.
TL;DR: By 180 days, wound strength and collagen fiber morphology were close to that observed in the normal skin, and observations show a direct relationship between collagen fiber diameter and tensile strength.
Abstract: Dermal repair tissue shows a progressive increase in collagen content which may be related to the wound tensile strength. Wound strength and extensibility are lower than those found in normal skin. In animals, wounds closed by metal clips are chosen as a model to study the proliferative and remodeling phases of healing from a mechanical and morphological point of view. During the proliferative phase the low wound strength is associated with formation of collagen fibers of small diameter, later, (days 28-45) an acute change appears corresponding to the remodeling phase, with increased collagen fiber diameters observed by scanning electron microscopy and light microscopy, and increased tensile strength and toughness. By 180 days, wound strength and collagen fiber morphology were close to that observed in the normal skin. These observations show a direct relationship between collagen fiber diameter and tensile strength. In addition, packing density of collagen fibrils (determined by the birefringence retardation per unit thickness under polarized light) was unchanged until day 90, although collagen fiber diameters increased during this time.
TL;DR: An adaptation of the quadtree data structure that represents polygonal maps is described in a manner that is also useful for the manipulation of arbitrary collections of straight line segments and is compared conceptually to the K-structure and the layered dag with respect to typical cartographic data.
Abstract: An adaptation of the quadtree data structure that represents polygonal maps (i.e., collections of polygons, possibly containing holes) is described ina manner that is also useful for the manipulation of arbitrary collections of straight line segments. The gol is to store these maps without the loss of information that results from digitization, and to obtain a worst-case execution time that is not overly sensitive to the positioning of the map. A regular decomposition variant of the region quadtree is used to organize the vertices and edges of the maps. A number of related data organizations are proposed in an iterative manner until a method is obtained that meets the stated goals. The result is termed a PM (polygonal map) quadtree and is based on a regular decomposition point space quadtree (PR quadtree) that stores additional information about the edges at its terminal nodes. Algorithms are given for inserting and deleting line segments from a PM quadtree. Use of the PM quadtree to perform point location, dynamic line insertion, and map overlay is discussed. The PM quadtree is compared conceptually to the K-structure and the layered dag with respect to typical cartographic data. An empirical comparison of the PM quadtree with other quadtree-based representations for polygonal maps is also provided.
TL;DR: The sol-gel process is a technique which is applicable for forming ceramic materials as discussed by the authors, where liquid precursor materials are reacted to form a sol which then polymerizes into an inorganic polymeric gel.
Abstract: The sol-gel process is a technique which is applicable for forming ceramic materials. In this process, liquid precursor materials are reacted to form a sol which then polymerizes into an inorganic polymeric gel. Advantages of this process over standard powder preparation of ceramics are: purity, homogeneity, control of macro- and micro-structures, and low processing temperatures. In our laboratory the sol-gel process has been used to form lead titanate. We detail a procedure which has produced dried monolithic gels up to 1.5 cm in diameter. The as-dried gels have not been exposed to temperatures above 40‡ C and are X-ray amorphous. Samples of the gels were crushed into powder and heated at 8‡ C min−1 to various temperatures up to 500‡ C, held for a variety of times, and then cooled to room temperature. After certain annealing procedures crystalline phases were observed. The initial crystalline phase to emerge has not yet been identified. Upon further annealing this phase transforms to tetragonal PbTiO3.
TL;DR: In this paper, the effects of process parameters such as amounts of water and acid alkoxide molarity on the gelation time as well as on the structure of the gels obtained were examined.
Abstract: Lead titanate gels have been prepared by adding an aqueous nitric acid solution to a Pb-Ti complex alkoxide. A systematic study was made to examine the effects of process parameters such as amounts of water and acid alkoxide molarity on the gelation time as well as on the structure of the gels obtained. The gel structure was characterized by the elastic modulus which was determined via sound wave propagation through the gels. It was found that an increase in both the amount of water and alkoxide molarity caused rapid gelation. Acid additions not only suppressed gelation but also reduced the elastic moduli of the resultant gels. Gels having a low elastic modulus were found to be desirable for the suppression of cracking during ageing and drying. Addition of an excessive amount of acid, however, prevented the formation of a large scale polymer-network and resulted in a powder-like gel. The porosity and dielectric constant of dried gels are also reported.
TL;DR: Une etude par methode Monte Carlo dans le cas of particules spheriques, montre qu'une plus forte force d'interaction peut soit augmenter, soit diminuer la fraction volumique necessaire a la percolation.
Abstract: A Monte Carlo study of spherical particles shows that increased interaction strength may either raise or lower the volume fraction required for percolation. The sense of the change depends on the distance at which two particles are considered connected, the dimensionality, and the proximity to the critical temperature. An on-lattice simulation supports the continuum result.
TL;DR: Analysis of the laminin-type IV complexes indicates that lamination binds to type IV collagen via the globular regions of either of its four arms, supported by experiments using fragment P1 of lamin in which does not bind to typeIV collagen in a specific way.
Abstract: A mixture of laminin and type IV collagen was analyzed by rotary shadowing using carbon/platinum and electron microscopy. Laminin was found to form distinct complexes with type IV collagen: one site of interaction is located 140 nm from the COOH-terminal, noncollagenous (NC1) domain and the other is located within the NH2-terminal region. The isolated NC1 fragment of type IV collagen does not appear to interact with laminin, while pepsin-treated type IV collagen, which lacks the NC1 domain, retains its ability to form complexes with laminin. Analysis of the laminin-type IV complexes indicates that laminin binds to type IV collagen via the globular regions of either of its four arms. This finding is supported by experiments using fragment P1 of laminin which lacks the globular regions and which does not bind to type IV collagen in a specific way. In addition, after heat-denaturation of laminin no specific binding is observed.
TL;DR: In this article, the exchange-correlation functional of Langreth and Mehl was generalized to include spin dependence and applied to the calculation of ground-state and electron removal energies in atoms.
Abstract: The exchange-correlation functional of Langreth and Mehl [Phys. Rev. B28, 1809 (1983)] is generalized to include spin dependence. It is then applied to the calculation of ground-state and electron removal energies in atoms. A functional for the correlation energy alone is also given, for use in cases where exchange can be calculated exactly.
TL;DR: Four of the nine patients with the acquired immunodeficiency syndrome and nocardia or streptomyces infections whose cases were reported to the Centers for Disease Control also had mycobacterial disease.
Abstract: Four parenteral drug abusers with the acquired immunodeficiency syndrome had nonmycobacterial actinomycetales infections. Three patients had nocardiosis and one developed a streptomyces ly...