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Showing papers by "Cornell University published in 1987"


Journal ArticleDOI
TL;DR: The method of classifying comorbidity provides a simple, readily applicable and valid method of estimating risk of death fromComorbid disease for use in longitudinal studies and further work in larger populations is still required to refine the approach.

39,961 citations


Journal ArticleDOI
17 Dec 1987-Nature
TL;DR: Protection against shock, vital organ dysfunction, persistent stress hormone release and death was conferred by administration of antibodies 2 h before bacterial infusion, indicating that cachectin is a mediator of fatal bacteraemic shock and suggesting that antibodies against Cachectin offer a potential therapy of life-threatening infection.
Abstract: Bacterial infection of the mammalian bloodstream can lead to overwhelming sepsis, a potentially fatal syndrome of irreversible cardiovascular collapse (shock) and critical organ failure. Cachectin, also known as tumour necrosis factor, is a macrophage-derived peptide hormone released in response to bacterial lipopolysaccharide, and it has been implicated as a principal mediator of endotoxic shock, although its function in bacterial sepsis is not known. Anaesthetized baboons were passively immunized against endogenous cachectin and subsequently infused with an LD100 dose of live Escherichia coli. Control animals (not immunized against cachectin) developed hypotension followed by lethal renal and pulmonary failure. Neutralizing monoclonal anti-cachectin antibody fragments (F(ab′)2) administered to baboons only one hour before bacterial challenge protected against shock, but did not prevent critical organ failure. Complete protection against shock, vital organ dysfunction, persistent stress hormone release and death was conferred by administration of antibodies 2 h before bacterial infusion. These results indicate that cachectin is a mediator of fatal bacteraemic shock, and suggest that antibodies against cachectin offer a potential therapy of life-threatening infection.

2,568 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of trade size on security prices was investigated and it was shown that informed traders tend to trade larger amounts at any given price, and market makers' pricing strategies must also depend on trade size.

2,287 citations


Journal ArticleDOI
07 May 1987-Nature
TL;DR: In this article, small tungsten particles (microprojectiles) are used to carry RNA or DNA into epidermal tissue of onion and these molecules were subsequently expressed genetically.
Abstract: We report here a novel phenomenon, namely that nucleic acids can be delivered into plant cells using high-velocity microprojec-tiles. This research was conducted in the hope of circumventing some of the inherent limitations of existing methods for delivering DNA into plant cells1–6. After being accelerated, small tungsten particles (microprojectiles) pierce cell walls and membranes and enter intact plant cells without killing them. Microprojectiles were used to carry RNA or DNA into epidermal tissue of onion and these molecules were subsequently expressed genetically. This approach can therefore be used to study the transient expression of foreign genes in an intact tissue. It remains to be shown that smaller cell types, as are found in regenerable plant tissues, can be stably transformed by this method. If this proves possible, it would appear to provide a broadly applicable transformation mechanism capable of circumventing the host-range restrictions of Agrobacterium tumefaciens1, and the regeneration problems of protoplast transformation2–5.

1,582 citations


Journal ArticleDOI
TL;DR: This article develops parts of a universal theory of adaptation on correlated landscapes by adaptive processes that have sufficient numbers of mutations per individual to "jump beyond" the correlation lengths in the underlying landscape.

1,354 citations


Journal ArticleDOI
TL;DR: The Monte Carlo-minimization method has located the lowest-energy minimum thus far reported for the brain pentapeptide [Met5]enkephalin in the absence of water, presumably it is the global minimum-energy structure.
Abstract: A Monte Carlo-minimization method has been developed to overcome the multiple-minima problem. The Metropolis Monte Carlo sampling, assisted by energy minimization, surmounts intervening barriers in moving through successive discrete local minima in the multidimensional energy surface. The method has located the lowest-energy minimum thus far reported for the brain pentapeptide [Met5]enkephalin in the absence of water. Presumably it is the global minimum-energy structure. This supports the concept that protein folding may be a Markov process. In the presence of water, the molecules appear to exist as an ensemble of different conformations.

1,305 citations


Journal ArticleDOI
TL;DR: A review of several uses for the protocols in the ISIS system, which supports fault-tolerant resilient objects and bulletin boards, illustrates the significant simplification of higher level algorithms made possible by the approach.
Abstract: The design and correctness of a communication facility for a distributed computer system are reported on. The facility provides support for fault-tolerant process groups in the form of a family of reliable multicast protocols that can be used in both local- and wide-area networks. These protocols attain high levels of concurrency, while respecting application-specific delivery ordering constraints, and have varying cost and performance that depend on the degree of ordering desired. In particular, a protocol that enforces causal delivery orderings is introduced and shown to be a valuable alternative to conventional asynchronous communication protocols. The facility also ensures that the processes belonging to a fault-tolerant process group will observe consistent orderings of events affecting the group as a whole, including process failures, recoveries, migration, and dynamic changes to group properties like member rankings. A review of several uses for the protocols in the ISIS system, which supports fault-tolerant resilient objects and bulletin boards, illustrates the significant simplification of higher level algorithms made possible by our approach.

1,094 citations


Book ChapterDOI
19 Oct 1987
TL;DR: Plant hormones are a group of naturally occurring, organic substances which influence physiological processes at low concentrations, mainly of growth, differentiation and development, though other processes, such as stomatal movement, may also be affected.
Abstract: Plant hormones are a group of naturally occurring, organic substances which influence physiological processes at low concentrations. The processes influenced consist mainly of growth, differentiation and development, though other processes, such as stomatal movement, may also be affected. Plant hormones1 have also been referred to as ‘phytohormones’ though this term is infrequently used.

1,067 citations


Journal ArticleDOI
30 Oct 1987-Science
TL;DR: The results show that the majority of the renal receptors of ANF are biologically silent, and this new class of receptors may serve as specific peripheral storage-clearance binding sites, acting as a hormonal buffer system to modulate plasma levels of ANf.
Abstract: A ring-deleted analog of atrial natriuretic factor--des[Gln18, Ser19, Gly20, Leu21, Gly22] ANF4-23-NH2 (C-ANF4-23)--binds with high affinity to approximately 99% of ANF receptors in the isolated perfused rat kidney. In this preparation, C-ANF4-23 is devoid of detectable renal effects and does not antagonize any of the known renal hemodynamic and natriuretic actions of biologically active ANF1-28. In contrast, both C-ANF4-23 and ANF1-28 increase sodium excretion and decrease blood pressure in intact anesthetized rats. This apparent contradiction is resolved by the finding that the ring-deleted analog markedly increases plasma levels of endogenous immunoreactive ANF in the rat. The results show that the majority of the renal receptors of ANF are biologically silent. This new class of receptors may serve as specific peripheral storage-clearance binding sites, acting as a hormonal buffer system to modulate plasma levels of ANF.

936 citations


Journal ArticleDOI
TL;DR: In this paper, the authors numerically solve the call option valuation problem given a fairly general continuous stochastic process for return volatility and derive statistical estimators for volatility process parameters, and parameter estimates for several individual stocks and indices.

927 citations


Journal ArticleDOI
TL;DR: In this article, the authors consider the problem of bringing a distributed system to a consistent state after transient failures, and propose a distributed algorithm to create consistent checkpoints, as well as a rollback-recovery algorithm to recover the system from transient failures.
Abstract: We consider the problem of bringing a distributed system to a consistent state after transient failures. We address the two components of this problem by describing a distributed algorithm to create consistent checkpoints, as well as a rollback-recovery algorithm to recover the system to a consistent state. In contrast to previous algorithms, they tolerate failures that occur during their executions. Furthermore, when a process takes a checkpoint, a minimal number of additional processes are forced to take checkpoints. Similarly, when a process rolls back and restarts after a failure, a minimal number of additional processes are forced to roll back with it. Our algorithms require each process to store at most two checkpoints in stable storage. This storage requirement is shown to be minimal under general assumptions.

Journal ArticleDOI
TL;DR: The thermal conductivity of AIN has been measured from 0.4 to 1800 K as discussed by the authors, and it has been shown that the heat conduction is by phonons and that at the lowest temperatures the phonon mean-free-path, l, is limited by boundary scattering.

Journal ArticleDOI
Carl Nathan1
TL;DR: The results suggest that PMN adherent to intra- or extravascular surfaces may undergo a massive, prolonged respiratory burst at the command of macrophages and lymphocytes reacting to microbial products and antigens.
Abstract: Recombinant tumor necrosis factor alpha (rTNF alpha) and beta (rTNF beta) did not trigger H2O2 release from PMN in suspension. However, when PMN were plated on polystyrene surfaces coated with serum, fibronectin, vitronectin, laminin, or human umbilical vein endothelial cells (HUVEC), rTNFs induced a massive, prolonged secretory response, similar to that elicited by phorbol myristate acetate (PMA) or bacteria. On serum-coated plates, the maximum sustained rate of H2O2 release in response to rTNF alpha was 2.6 +/- 0.2 nmol/min per 10(6) PMN, the same as that with PMA; release continued for 73 +/- 4 min. On laminin-coated surfaces or HUVEC, release of H2O2 in response to rTNFs was slower, but lasted approximately 3.5 h, reaching the same total (greater than 100 nmol/10(6) PMN). Not only was this response far longer and larger than for other soluble stimuli of the respiratory burst studied with PMN in suspension, but the concentration necessary to elicit a half-maximal response (EC50) for rTNF alpha was orders of magnitude lower (55 pM). Responses were similar with FMLP, but ranged from zero to small with recombinant IFN alpha, recombinant IFN beta, recombinant IFN gamma, platelet-derived growth factor, recombinant IL-1 beta, or bacterial lipopolysaccharide. Adherent monocytes did not secrete H2O2 in response to rTNFs. H2O2 secretion by adherent PMN was first detectable 15-90 min after addition of rTNFs or FMLP. This lag period was unaffected by prior exposure of PMN to rTNF alpha in suspension, by allowing PMN to adhere before adding rTNF alpha, or by incubating adherent PMN in medium conditioned by rTNF alpha-treated PMN. Cytochalasins abolished H2O2 secretion in response to rTNFs, but not FMLP, if added during, but not after, the lag period. Thus, H2O2 secretion from rTNF alpha-treated PMN appears to be a direct but delayed response that requires assembly of microfilaments during exposure to the cytokine. These results suggest that PMN adherent to intra- or extravascular surfaces may undergo a massive, prolonged respiratory burst at the command of macrophages and lymphocytes reacting to microbial products and antigens.

Journal ArticleDOI
01 Nov 1987
TL;DR: It is argued that this approach to building distributed and fault-tolerant software is more straightforward, more flexible, and more likely to yield correct solutions than alternative approaches.
Abstract: We describe applications of a virtually synchronous environment for distributed programming, which underlies a collection of distributed programming tools in the ISIS2 system. A virtually synchronous environment allows processes to be structured into process groups, and makes events like broadcasts to the group as an entity, group membership changes, and even migration of an activity from one place to another appear to occur instantaneously — in other words, synchronously. A major advantage to this approach is that many aspects of a distributed application can be treated independently without compromising correctness. Moreover, user code that is designed as if the system were synchronous can often be executed concurrently. We argue that this approach to building distributed and fault-tolerant software is more straightforward, more flexible, and more likely to yield correct solutions than alternative approaches.

Journal ArticleDOI
TL;DR: In this paper, the authors examined several indices used to measure the frequency of association between individuals in fission/fusion societies, under specific conditions likely to be encountered in field studies of animal behaviour.

Journal ArticleDOI
TL;DR: Epidemiological models with nonlinear incidence rates λIpSq show a much wider range of dynamical behaviors than do those with bilinear incidence ratesλIS, and these behaviors are determined mainly by p and λ, and secondarily by q.
Abstract: Epidemiological models with nonlinear incidence rates λIpSqshow a much wider range of dynamical behaviors than do those with bilinear incidence rates λIS. These behaviors are determined mainly by p and λ, and secondarily by q. For such models, there may exist multiple attractive basins in phase space; thus whether or not the disease will eventually die out may depend not only upon the parameters, but also upon the initial conditions. In some cases, periodic solutions may appear by Hopf bifurcation at critical parameter values.

Journal ArticleDOI
TL;DR: The proofs expose general heuristic principles that explain why consensus is possible in certain models but not possible in others, and several critical system parameters, including various synchronicity conditions, are identified.
Abstract: Reaching agreement is a primitive of distributed computing. Whereas this poses no problem in an ideal, failure-free environment, it imposes certain constraints on the capabilities of an actual system: A system is viable only if it permits the existence of consensus protocols tolerant to some number of failures. Fischer et al. have shown that in a completely asynchronous model, even one failure cannot be tolerated. In this paper their work is extended: Several critical system parameters, including various synchrony conditions, are identified and how varying these affects the number of faults that can be tolerated is examined. The proofs expose general heuristic principles that explain why consensus is possible in certain models but not possible in others.

Journal ArticleDOI
TL;DR: In this paper, the authors measured the thermal conductivity of polymethylmethacrylate (PMMA), amorphous polymorphous polyamide, Ca-K nitrate glass, three polyamide-based glasses, and glycerol in the temperature range 30-300 K using an ac technique that eliminates errors from blackbody radiation.
Abstract: We have measured the thermal conductivity of polymethylmethacrylate (PMMA), amorphous ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$, Ca-K nitrate glass, three ${\mathrm{SiO}}_{2}$-based glasses, and glycerol in the temperature range 30--300 K, using an ac technique that eliminates errors from blackbody radiation. This technique and the problems of blackbody radiation in thermal measurements are discussed in detail. Our data do not support a recent prediction of heat transport by fractons. Instead, we find that the thermal conductivity of these glasses above \ensuremath{\sim}50 K is well described by the minimum thermal conductivity suggested by Slack.

Journal ArticleDOI
TL;DR: Brain slides from all patients with anoxic-ischemic encephalopathy and a well-documented cardiorespiratory arrest were reexamined, finding delayed hippocampal injury now documented in humans provides a target for possible therapy that can be initiated after cardiopulmonary resuscitation.
Abstract: Transient ischemia in animals produces delayed cell death in vulnerable hippocampal neurons. To see if this occurs in humans, we reexamined brain slides from all patients with anoxic-ischemic encephalopathy and a well-documented cardiorespiratory arrest. Eight patients dying 18 hours or less after cardiac arrest had minimal damage in hippocampus and moderate damage in cerebral cortex and putamen. Six patients living 24 hours or more had severe damage in all four regions. The increase in damage with time postarrest was significant only in the hippocampus. Delayed hippocampal injury now documented in humans provides a target for possible therapy that can be initiated after cardiopulmonary resuscitation.

Book
James Renegar1
01 Jan 1987
TL;DR: This compact book will take a reader who knows little of interior-point methods to within sight of the research frontier, developing key ideas that were over a decade in the making by numerous interior- point method researchers.
Abstract: This compact book, through the simplifying perspective it presents, will take a reader who knows little of interior-point methods to within sight of the research frontier, developing key ideas that were over a decade in the making by numerous interior-point method researchers. It aims at developing a thorough understanding of the most general theory for interior-point methods, a class of algorithms for convex optimization problems. The study of these algorithms has dominated the continuous optimization literature for nearly 15 years. In that time, the theory has matured tremendously, but much of the literature is difficult to understand, even for specialists. By focusing only on essential elements of the theory and emphasizing the underlying geometry, A Mathematical View of Interior-Point Methods in Convex Optimization makes the theory accessible to a wide audience, allowing them to quickly develop a fundamental understanding of the material.

Proceedings ArticleDOI
01 Jan 1987
TL;DR: A new algorithm for finding a maximum matching in a general graph that its only computationally non-trivial step is the inversion of a single integer matrix, the isolating lemma, and other applications to parallel computation and randomized reductions are shown.
Abstract: We present a new algorithm for finding a maximum matching in a general graph. The special feature of our algorithm is that its only computationally non-trivial step is the inversion of a single integer matrix. Since this step can be parallelized, we get a simple parallel (RNC 2) algorithm. At the heart of our algorithm lies a probabilistic lemma, the isolating lemma. We show other applications of this lemma to parallel computation and randomized reductions.

Journal ArticleDOI
C K Chou1, T J Dull1, D S Russell1, R Gherzi, D Lebwohl, A Ullrich, Ora M. Rosen 
TL;DR: In this paper, the effects of substitution of alanine for lysine at amino acid 1018 in the ATP-binding domain of the beta subunit of the human β-subunit were investigated.

Journal ArticleDOI
TL;DR: In this paper, a simple set of rules for constructing ultraviolet-finite closed fermionic string models is presented, based on a fermionics formulation of all internal (i.e. toroidally compactified) coordinates.

Journal ArticleDOI
TL;DR: An acceleration device has been designed and constructed which can accelerate small tungsten particles to velocities of about 1,000 to 2,000 ft/sec, and it is found that these particles can penetrate cell walls and membranes and enter cells in a nonlethal manner.
Abstract: Biologists commonly wish to introduce a wide range of substances into living cells. Such substances include biological stains, proteins (antibodies or enzymes), and genetic material (either RNA or DNA). The cell membrane and, in the case of plant ceils, the cell wall pose formidable barriers which exclude many macromolecules. The concept of particle bombardment has been put forward as a universal mechanism for transporting substances into any living cell. An acceleration device has been designed and constructed which can accelerate small tungsten particles (1 to 4 urn in diameter) to velocities of about 1,000 to 2,000 ft/sec. We have found that these particles can penetrate cell walls and membranes and enter cells in a nonlethal manner. Thousands of cells can be penetrated simultaneously, in situ, as they occur in tissues. Particle bombardment has been shown to be effective in delivering foreign substances into a variety of plant species, including onion, tobacco, corn, and rice. This new method ...

Journal ArticleDOI
TL;DR: In this article, the stable isotopes of sulfur, nitrogen, and carbon were used to trace organic matter flow in salt marshes and cstuarinc waters at Sapelo Island, Georgia.
Abstract: The stable isotopes of sulfur, nitrogen, and carbon were used to trace organic matter flow in salt marshes and cstuarinc waters at Sapelo Island, Georgia. Organic matter inputs from terrestrial sources as detrital input either from forests adjacent to the marshes or from rivers were not dctcctable by their isotopic signatures in estuarine consumers. The results suggest that there are two major sources of organic matter for the fauna of the marshes and estuarine waters of Sapelo Island: Spartina and algae. The long-standing debate about the relative importance of Spartina detritus and algae in supporting marsh and estuarine secondary production appears from this analysis to be a draw; both sources are important and their relative importance is determined by feeding mode, size, location, and trophic position of the marsh and estuarine consumers.

Journal ArticleDOI
TL;DR: An 88-kD membrane glycoprotein present in platelets, endothelial cells, monocytes, and a variety of human tumor cell lines that is the membrane binding site for TSP is identified and isolated and may function as the cellular TSP receptor.
Abstract: Thrombospondin (TSP), a 450-kD multifunctional glycoprotein with a broad tissue distribution, is secreted upon platelet stimulation, binds to the activated platelet surface, and supports platelet aggregation. We have identified and isolated an 88-kd membrane glycoprotein present in platelets, endothelial cells, monocytes, and a variety of human tumor cell lines that is the membrane binding site for TSP. Endogenous platelet TSP binding to thrombin- and ionophore-stimulated human platelets was inhibited in the presence of the monoclonal antibody OKM5. TSP binding to C32 melanoma cells and HT1080 fibrosarcoma cells was specific and also inhibitable with OKM5 Mab. Cell labeling followed by specific immunoprecipitation demonstrated biosynthesis of a single 88-kD glycoprotein. Binding of TSP to the isolated membrane protein was specific and saturable. These studies identify an 88-kD membrane glycoprotein that reacts with the monoclonal antibody, OKM5, and may function as the cellular TSP receptor.

Journal ArticleDOI
TL;DR: A new algorithm for finding a maximum matching in a general graph with special feature is that its only computationally non-trivial step is the inversion of a single integer matrix, the isolating lemma.
Abstract: We present a new algorithm for finding a maximum matching in a general graph. The special feature of our algorithm is that its only computationally non-trivial step is the inversion of a single integer matrix. Since this step can be parallelized, we get a simple parallel (RNC 2) algorithm. At the heart of our algorithm lies a probabilistic lemma, the isolating lemma. We show other applications of this lemma to parallel computation and randomized reductions.

Journal ArticleDOI
TL;DR: It is suggested that habitual, unrestricted consumption of low-fat diets may be an effective approach to weight control.

Journal ArticleDOI
TL;DR: In this paper, the authors make an attempt to demystify the language of solid-state physics, drawing explicit parallels to well-known concepts in theoretical chemistry to find localized bonds among all those maximally delocalized bands.
Abstract: To make sense of the marvelous electronic properties of the solid state, chemists must learn the language of solid-state physics, of band structures. An attempt is made here to demystify that language, drawing explicit parallels to well-known concepts in theoretical chemistry To the joint search of physicists and chemists for understanding of the bonding in extended systems, the chemist brings a great deal of intuition and some simple but powerful notions. Most important among these is the idea of a bond, and the use of frontier-orbital arguments. How to find localized bonds among all those maximally delocalized bands? Interpretative constructs, such as the density of states, the decomposition of these densities, and crystal orbital overlap populations, allow a recovery of bonds, a finding of the frontier orbitals that control structure and reactivity in extended systems as well as discrete molecules.