bluuebunny/crossref_metadata_2025 huggingface dataset:
Pipeline Architecture
Authors: Ramamoorthy C. V. , Li H. F.
Published: July 2002

Pipelined computer architecture has received considerable attention since the 1960s when the need for faster and more cost-effective systems became critical. The merit of pipelining is that it can help to match the speeds of various subsystems without duplicating the cost of the entire system involved. As technology evolves, faster and cheaper LSI circuits become available, and the future of pipelining, either in a simple or complex form, becomes more promising.

This paper reviews the many theoretical considerations and problems behind pipelining, surveying and comparing various representative pipeline machines that operate in either sequential or vector pipeline mode, the practical solutions adopted, and the tradeoffs involved. The performance of a simple pipe, the physical speed limitation, and the control structures for penalty-incurring events are analyzed separately. The problems faced by the system designers are tackled, including buffering, busing structur, branching, and interrupt handling. Aspects of sequential and vector processing are studied. Fundamental advantages of vector processing are unveiled, and additional requirements (costs) are discussed to establish a criterion for the tradeoff between sequential and vector pipeline processing. Finally, two recent machines (the CRAY-1 and the Amdahl 470 V/6 systems) are presented to demonstrate how complex pipeline techniques can be used and how simple but advantageous pipeline concepts can be exploited.
An overview of computational complexity
Authors: Cook Stephen A.
Published: July 2002

An historical overview of computational complexity is presented. Emphasis is on the fundamental issues of defining the intrinsic computational complexity of a problem and proving upper and lower bounds on the complexity of problems. Probabilistic and parallel computation are discussed.
On the implementation of security measures in information systems
Authors: Conway R. W. , Maxwell W. L. , Morgan H. L.
Published: July 2002

The security of an information system may be represented by a model matrix whose elements are decision rules and whose row and column indices are users and data items respectively. A set of four functions is used to access this matrix at translation and execution time. Distinguishing between data dependent and data independent decision rules enables one to perform much of the checking of security only once at translation time rather than repeatedly at execution time. The model is used to explain security features of several existing systems, and serves as a framework for a proposal for general security system implementation within today's languages and operating systems.
Design and implementation of a diagnostic compiler for PL/I
Authors: Conway Richard W. , Wilcox Thomas R.
Published: July 2002

PL/C is a compiler for a dialect for PL/I. The design objective was to provide a maximum degree of diagnostic assistance in a batch processing environment. For the most part this assistance is implicit and is provided automatically by the compiler. The most remarkable characteristic of PL/C is its perseverance—it completes translation of every program submitted and continues execution until a user-established error limit is reached. This requires that the compiler repair errors encountered during both translation and execution, and the design of PL/C is dominated by this consideration.

PL/C also introduces several explicit user-controlled facilities for program testing. To accommodate these extensions to PL/I without abandoning compatibility with the IBM compiler, PL/C permits “pseudo comments”—constructions whose contents can optionally be considered either source text or comment.

In spite of the diagnostic effort PL/C is a fast and efficient processor. It effectively demonstrates that compilers can provide better diagnostic assistance than is customarily offered, even when a sophisticated source language is employed, and that this assistance need not be prohibitively costly.
A class of dynamic memory allocation algorithms
Authors: Hirschberg Daniel S.
Published: July 2002

A new dynamic memory allocation algorithm, the Fibonacci system, is introduced. This algorithm is similar to, but seems to have certain advantages over, the “buddy” system. A generalization is mentioned which includes both of these systems as special cases.
An undergraduate program in computer science—preliminary recommendations
Authors: Conte S. D. , Hamblen John W. , Kehl William B. , Navarro Silvio O. , Rheinboldt Werner C. , Young David M. , Atchinson William F.
Published: July 2002

The Curriculum Committee on Computer Science (C
3
S) of the Association for Computing Machinery has been considering curriculum problems for approximately three years. During the early part of this period, a number of informal sessions were held with computer people at various national meetings. In the latter part of this three-year period, the Committee has been formally organized and has made a definite effort to arrive at a concrete suggestions for a curriculum.
Multiprogram scheduling
Authors: Codd E. F.
Published: July 2002

In order to exploit fully a fast computer which possesses simultaneous processing abilities, it should to a large extent schedule its own workload. The scheduling routine must be capable of extremely rapid execution if it is not to prove self-defeating.

The construction of a schedule entails determining which programs are to be run concurrently and which sequentially with respect to each other. A concise scheduling algorithm is described which tends to minimize the time for executing the entire pending workload (or any subset of it), subject to external constraints such as precedence, urgency, etc. The algorithm is applicable to a wide class of machines.
Convex quadratic and semidefinite programming relaxations in scheduling
Authors: Skutella Martin
Published: July 2002

We consider the problem of scheduling unrelated parallel machines subject to release dates so as to minimize the total weighted completion time of jobs. The main contribution of this paper is a provably good convex quadratic programming relaxation of strongly polynomial size for this problem. The best previously known approximation algorithms are based on LP relaxations in time- or interval-indexed variables. Those LP relaxations, however, suffer from a huge number of variables. As a result of the convex quadratic programming approach we can give a very simple and easy to analyze 2-approximation algorithm which can be further improved to performance guarantee 3/2 in the absence of release dates. We also consider preemptive scheduling problems and derive approximation algorithms and results on the power of preemption which improve upon the best previously known results for these settings. Finally, for the special case of two machines we introduce a more sophisticated semidefinite programming relaxation and apply the random hyperplane technique introduced by Goemans and Williamson for the MaxCut problem; this leads to an improved 1.2752-approximation.
Poly-logarithmic deterministic fully-dynamic algorithms for connectivity, minimum spanning tree, 2-edge, and biconnectivity
Authors: Holm Jacob , de Lichtenberg Kristian , Thorup Mikkel
Published: July 2002

Deterministic fully dynamic graph algorithms are presented for connectivity, minimum spanning tree, 2-edge connectivity, and biconnectivity. Assuming that we start with no edges in a graph with
n
vertices, the amortized operation costs are
O
(log
2
n
) for connectivity,
O
(log
4
n
) for minimum spanning forest, 2-edge connectivity, and
O
(log
5
n
) biconnectivity.
Accomplishing software stability
Authors: Fayad Mohamed
Published: July 2002

The kitchen proves an ideal setting to illustrate how stability and change work together within software.
A comment on “a fast parallel algorithm for thinning digital patterns”
Authors: Lü H. E. , Wang P. S. P.
Published: July 2002

A fast parallel thinning algorithm for digital patterns is presented. This algorithm is an improved version of the algorithms introduced by Zhang and Suen [5] and Stefanelli and Rosenfeld [3]. An experiment using an Apple II and an Epson printer was conducted. The results show that the improved algorithm overcomes some of the disadvantages found in [5] by preserving necessary and essential structures for certain patterns which should not be deleted and maintains very fast speed, from about 1.5 to 2.3 times faster than the four-step and two-step methods described in [3] although the resulting skeletons look basically the same.
Projective transformations of the parameter of a Bernstein-Bézier curve
Authors: Patterson Richard R.
Published: July 2002

The definitions of polynomial and rational Bernstein-Bézier curves are reviewed and extended to include homogeneous parametrizations. Then the effects of a projective transformation of the parameter space are described in terms of a group representation. This representation is used to answer the following questions: (1) If the control points are held fixed, when do two different sets of weights determine the same rational curve? (2) How do we find the control points for a subdivision of the original curve?
Multiple-knot and rational cubic beta-splines
Authors: Joe Barry
Published: July 2002

Goodman (Properties of Beta-splines.
J. Approx. Theory 44
, 2 (June 1985), 132-153) gave an explicit formula for cubic Beta-splines on a uniform knot sequence with varying β1 and β2 values at the knots. We establish an alternative explicit formula for cubic Beta-splines on a nonuniform knot sequence with constant β1 = 1 and varying β2 values at the knots. This alternative formula can also be used if the knot sequence contains multiple knots, and is useful for knot insertion. We show how to efficiently evaluate a cubic Beta-spline curve at many values using this formula. We introduce rational cubic Beta-spline curves and surfaces that have extra weight parameters for shape control, and show that they satisfy the same geometric continuity conditions and properties as nonrational cubic Beta-spline curves and surfaces.
BIPOLAR MOLECULAR OUTFLOWS FROM YOUNG STARS AND PROTOSTARS
Authors: Bachiller Rafael
Published: July 2002

▪ Abstract  A violent outflow of high-velocity gas is one of the first manifestations of the formation of a new star. Such outflows emerge bipolarly from the young object and involve amounts of energy similar to those involved in accretion processes. The youngest (proto-)stellar low-mass objects known to date (the Class 0 protostars) present a particularly efficient outflow activity, indicating that outflow and infall motions happen simultaneously and are closely linked since the very first stages of the star formation processes.

This article reviews the wealth of information being provided by large millimeter-wave telescopes and interferometers on the small-scale structure of molecular outflows, as well as the most recent theories about their origin. The observations of highly collimated CO outflows, extremely high velocity (EHV) flows, and molecular “bullets” are examined in detail, since they provide key information on the origin and propagation of outflows. The peculiar chemistry operating in the associated shocked molecular regions is discussed, highlighting the recent high-sensitivity observations of low-luminosity sources. The classification schemes and the properties of the driving sources of bipolar outflows are summarized with special attention devoted to the recently identified Class 0 protostars. All these issues are crucial for building a unified theory on the mass-loss phenomena in young stars.
The Search for Extraterrestrial Intelligence (SETI)
Authors: Tarter Jill
Published: July 2002

▪ Abstract  The search for evidence of extraterrestrial intelligence is placed in the broader astronomical context of the search for extrasolar planets and biomarkers of primitive life elsewhere in the universe. A decision tree of possible search strategies is presented as well as a brief history of the search for extraterrestrial intelligence (SETI) projects since 1960. The characteristics of 14 SETI projects currently operating on telescopes are discussed and compared using one of many possible figures of merit. Plans for SETI searches in the immediate and more distant future are outlined. Plans for success, the significance of null results, and some opinions on deliberate transmission of signals (as well as listening) are also included. SETI results to date are negative, but in reality, not much searching has yet been done.
ENVIRONMENTALLY CONSCIOUS CHEMICAL PROCESS DESIGN
Authors: Cano-Ruiz J. A. , McRae G. J.
Published: July 2002

▪ Abstract  The environment has emerged as an important determinant of the performance of the modern chemical industry. This paper reviews approaches for incorporating environmental issues into the design of new processes and manufacturing facilities. The organizational framework is the design process itself, which includes framing the problem and generating, analyzing, and evaluating alternatives. A historical perspective on the chemical process synthesis problem illustrates how both performance objectives and the context of the design have evolved to the point where environmental issues must be considered throughout the production chain. In particular, the review illustrates the need to view environmental issues as part of the design objectives rather than as constraints on operations. A concluding section identifies gaps in the literature and opportunities for additional research.
Insect Parapheromones in Olfaction Research and Semiochemical-Based Pest Control Strategies
Authors: Renou Michel , Guerrero Angel
Published: July 2002

▪ Abstract  The possibility of disrupting the chemical communication of insect pests has initiated the development of new semiochemicals, parapheromones, which are anthropogenic compounds structurally related to natural pheromone components. Modification at the chain and/or at the polar group, isosteric replacements, halogenation or introduction of labeled atoms have been the most common modifications of the pheromone structure. Parapheromones have shown a large variety of effects, and accordingly have been called agonists, pheromone mimics, synergists and hyperagonists, or else pheromone antagonists, antipheromones and inhibitors. Pheromone analogues have been used in quantitative structure-activity relationship studies of insect olfaction, and from a practical point of view they can replace pheromones when these are costly to prepare or unstable under field conditions.
Active Control of Sound
Authors: Peake N. , Crighton D. G.
Published: July 2002

▪ Abstract  The active control of sound waves has become an extraordinarily large and vigorous area of academic research and technological development. In this paper we describe the physical principles underlying the control of sound and review their application in a wide range of contexts. One scenario involves the control of noise from a primary source by the introduction of secondary sources, and this technique is described for fields in ducts, in free space, in enclosures (with particular reference to aircraft cabins), and for turbomachinery. A second scenario involves the use of the active control of sound to eliminate large-scale oscillations in more complicated flows, in which part of an unstable feedback cycle is mediated via acoustic waves. Successful applications of this idea include the control of combustion instabilities and compressor surge.
The Action of Molecular Chaperones in the Early Secretory Pathway
Authors: Fewell Sheara W. , Travers Kevin J. , Weissman Jonathan S. , Brodsky Jeffrey L.
Published: July 2002

▪ Abstract  The endoplasmic reticulum (ER) serves as a way-station during the biogenesis of nearly all secreted proteins, and associated with or housed within the ER are factors required to catalyze their import into the ER and facilitate their folding. To ensure that only properly folded proteins are secreted and to temper the effects of cellular stress, the ER can target aberrant proteins for degradation and/or adapt to the accumulation of misfolded proteins. Molecular chaperones play critical roles in each of these phenomena.
Sequence Variation in Genes and Genomic DNA: Methods for Large-Scale Analysis
Authors: Mir Kalim U. , Southern Edwin M.
Published: July 2002

The large-scale typing of sequence variation in genes and genomic DNA presents new challenges for which it is not clear that current technologies are sufficiently sensitive, robust, or scalable. This review surveys the current platform technologies: separation-based approaches, which include mass spectrometry; homogeneous assays; and solid-phase/array-based assays. We assess techniques for discovering and typing variation on a large scale, especially that of single-nucleotide polymorphisms. The in-depth focus is the DNA chip/array platform, and some of the published large-scale studies are closely examined. The problem of large-scale amplification is addressed, and emerging technologies for present and future needs are indicated.
MANAGEMENT OF ADULTS WITH CONGENITAL HEART DISEASE: An Increasing Problem
Authors: Somerville, MD, FRCP, FACC, FESC Jane
Published: July 2002

▪ Abstract  A small new population of patients in cardiology, the grown-up (adult) congenital hearts (GUCH), need superspecialist care and expertise, particularly those patients with complex defects previously operated on in childhood or who were not operated on. Arrhythmias are the most common cardiologic reason for admission to the hospital, and atrial flutter is the most frequent disorder of rhythm, usually related to hemodynamic disturbances. The GUCHs need solutions to problems of transition of care, ideally an adolescent area for the younger patients, knowledge of which and when to investigate each anomaly, expertise in cardiac catheterization and interventions, cardiac surgeons experienced in congenital as well as adult disease since one in five admissions are for cardiac surgery, at-risk pregnancy service, counseling on life's problems, and most of all a few dedicated centers with cardiologists and surgeons trained in this subspecialty. The profession needs to achieve optimal care for these precious patients, particularly those with complicated lesions and complex surgery, particularly with valve replacements. Although small in number and high in expense, GUCH patients should be centralized so expertise and experience can be concentrated despite the need to cross barriers of finance and bureaucracy. Currently, with the exception of a few expert centers, these patients receive suboptimal medical management.
Biology of Gastroesophageal Reflux Disease: Pathophysiology Relating to Medical and Surgical Treatment
Authors: DeMeester, MD Tom R. , Peters, MD Jeffrey H. , Bremner, MD Cedric G. , Chandrasoma, MD Parakh
Published: July 2002

This chapter reviews the biology of gastroesophageal reflux disease, relating pathophysiology to medical and surgical therapy. Various definitions of the disease are presented and workable criteria are developed to identify patients with the disease. The central importance of the lower esophageal high-pressure zone as a barrier to reflux is emphasized, along with an analysis of its biomechanical alteration in disease. The composition of the refluxed gastric juice is characterized in regard to its potential for mucosal injury. Evidence is provided that cardiac-type mucosa is an acquired sequel to acid-induced squamous mucosal injury in the terminal esophagus. A hypothesis regarding the process of intestinalization of cardiac-type mucosa to form Barrett's esophagus is presented. An integrated concept of the pathophysiology of gastroesophageal reflux disease is constructed. Practical concepts regarding the treatment of gastroesophageal reflux disease are developed, based on a review of studies on the natural history of the disease and the long-term outcome of therapy.
THE PATHOGENESIS OF TUBERCULOSIS
Authors: Rook G.A.W. , Hernandez-Pando Rogelio
Published: July 2002

Tuberculosis patients relapse if treatment is not continued for 6 months, because chemotherapy fails to convert the patients' response from the necrotizing pattern characteristic of disease (Koch phenomenon) to the nonnecrotizing bactericidal function required for optimal immunity. We need to understand the nature of these two immunological states and how to convert one to the other. Studies in mice and humans implicate differences in cytokine profiles and in metabolism of adrenal steroids. Either enhanced susceptibility or protection can be evoked in mice with appropriate doses of a killed environmental saprophyte. This emphasizes the importance of shared epitopes and may explain the geographically variable efficacy of Mycobacterium bovis Bacillus Calmette Guérin vaccination. Unlike soluble antigens of M. tuberculosis itself, which tend to evoke necrosis, the shared mycobacterial epitopes evoke little skin-test reactivity in patients. Preparations of these epitopes show potential as immunotherapeutic agents to convert the response from necrotic to bactericidal mode.
BACTERIA AS MODULAR ORGANISMS
Authors: Andrews John H.
Published: July 2002

▪ Abstract  The body plan of modular organisms is based on an indeterminate structure composed of iterated units or modules arrayed at various levels of complexity (such as leaves, twigs, and branches). Examples of modular organisms include plants and many sessile benthic invertebrates. In contrast, the body of unitary organisms is a determinate structure consisting usually of a strictly defined number of parts (such as legs or wings) established only during embryogenesis. Mobile animals are examples. Unlike that of unitary creatures, the form of a modular organism derives from a characteristic pattern of branching or budding of modules, which may remain attached or become separated to live physiologically independent lives as parts of a clone. Modular organisms tend to be sessile or passively mobile and, as genetic individuals, have the capacity for exponential increase in size. They do not necessarily undergo systemic senescence, and do not segregate somatic from germ line cells. It is argued here that bacteria are essentially modular organisms where the bacterial cell, microcolony, and macrocolony are modules of different levels of complexity analogous to modules of macroorganisms. This interpretation provides a broad conceptual basis for understanding the natural history of bacteria, and may illuminate the evolutionary origins and developmental biology of modular creatures.
SIGNAL TRANSDUCTION IN THE CAENORHABDITIS ELEGANS NERVOUS SYSTEM
Authors: Bargmann Cornelia I. , Kaplan Joshua M.
Published: July 2002

▪ Abstract  Caenorhabditis elegans interacts with its environment by sensing chemicals, touch, and temperature; genetic analysis of each of these responses has led to the identification of candidate signaling molecules within sensory neurons. A molecular model for touch sensation has emerged from studies of the mechanosensory response; the receptors and signal transduction mechanisms in olfactory neurons are being elucidated; and an unusual neuroendocrine role for a TGF-β-related peptide in chemosensory neurons has been discovered. Presynaptic and postsynaptic components of neuronal synapses have been identified in behavioral and pharmacological mutant screens. Mutations have been found in multiple classes of nicotinic acetylcholine receptor genes, excitatory and inhibitory glutamate receptor genes, and candidate gap junction genes, allowing their function to be studied in vivo. Different G-protein signaling pathways have characteristic effects on behavior, neuronal degeneration, and embryonic development.
PHYSIOLOGIC DETERMINANTS OF THE ANOREXIA OF AGING: Insights from Animal Studies
Authors: Horwitz Barbara A. , Blanton Cynthia A. , McDonald Roger B.
Published: July 2002

▪ Abstract  The anorexia of aging is a syndrome characterized by unexplained losses in food intake and body weight that occur near the end of life. Proposed etiologies cover a wide range of biological and psychological conditions. The observation of this phenomenon in older laboratory animals suggests that physiological changes play a significant causal role. Research on the neurochemical control of energy balance has received much attention in recent years, and age-related alterations in the neuropeptidergic effectors of food intake have been implicated in the anorexia of aging. This review provides an update on putative mechanisms underlying this dysregulation of feeding during advanced age.
Intracellular Signaling Mechanisms Activated by Cholecystokinin-Regulating Synthesis and Secretion of Digestive Enzymes in Pancreatic Acinar Cells
Authors: Williams John A
Published: July 2002

▪ Abstract  The intracellular signaling mechanisms by which cholecystokinin (CCK) and other secretagogues regulate pancreatic acinar function are more complex than originally realized. CCK couples through heterotrimeric G proteins of the Gq family to lead to an increase in intracellular free Ca2+, which shows spatial and temporal patterns of signaling. The actions of Ca2+ are mediated in part by activation of a number of Ca2+-activated protein kinases and the protein phosphatase calcineurin. By the process of exocytosis the intracellular messengers Ca2+, diacylglycerol, and cAMP activate the release of the zymogen granule content in a manner that is poorly understood. This fusion event most likely involves SNARE and Rab proteins present on zymogen granules and cellular membrane domains. More likely related to nonsecretory aspects of cell function, CCK also activates three MAPK cascades leading to activation of ERKs, JNKs, and p38 MAPK. Although the function of these pathways is not well understood, ERKs are probably related to cell growth, and through phosphorylation of hsp27, p38 can affect the actin cytoskeleton. The PI3K (phosphatidylinositol 3-kinase)-mTOR (mammalian target of rapamycin) pathway is important for regulation of acinar cell protein synthesis because it leads to both activation of p70S6K and regulation of the availability of eIF4E in response to CCK. CCK also activates a number of tyrosyl phosphorylation events including that of p125FAK and other proteins associated with focal adhesions.
Population Screening in Hereditary Hemochromatosis
Authors: Motulsky Arno G. , Beutler Ernest
Published: July 2002

▪ Abstract  Hemochromatosis is a common autosomal recessive condition found in the homozygous state in 1/200–1/400 people of northern-, central-, and western-European origin. It causes increased iron storage, which may lead to liver cirrhosis, liver cancer, heart disease, arthritis, and diabetes in many but not all affected adults, with a higher frequency in males. The condition is easily treated by repeated venesections without side effects but is frequently overlooked. Population screening of adults using iron indices alone or combined with DNA testing has therefore been recommended, but a consensus conference in 1997 recommended that such screening be deferred, owing to uncertainty regarding the extent of clinical disease that may develop in individuals detected by such programs. There was also concern that DNA screening results might be used for discrimination in insurance and occupational settings. Screening family members of patients with evidence of definite iron loading, however, is accepted by all observers. Because serious complications may be overlooked, a more aggressive stance toward case detection in the adult population has been advocated by some observers, realizing that unnecessary treatment might occur. Because additional information regarding the spectrum of clinical disease in homozygotes in now accumulating, a consensus conference in the near future is suggested to consider appropriate policies.
Functional Significance of Adenosine 5′-Diphosphate Receptor (P2Y
12
) in Platelet Activation Initiated by Binding of von Willebrand Factor to Platelet GP Ibα Induced by Conditions of High Shear Rate
Authors: Goto Shinya , Tamura Noriko , Eto Koji , Ikeda Yasuo , Handa Shunnosuke
Published: July 2002

Background

—

The role of the adenosine 5′-diphosphate receptor P2Y
12
in platelet activation initiated by the von Willebrand factor (VWF)–GP Ibα interaction under high shear rate was investigated.

Methods and Results

—

Blood samples were obtained from 11 donors. Shear-induced platelet aggregation was detected by optically modified cone-plate viscometer. Shear-induced VWF binding, P-selectin expression, and microparticle release were detected by flow cytometry. Platelet interaction with immobilized VWF was also investigated by parallel-plate flow chamber equipped with epifluorescent videomicroscopy. Effects of a selective P2Y
12
antagonist AR-C69931 MX were tested. AR-C69931 MX inhibited shear-induced platelet aggregation in a dose-dependent manner, achieving the maximum inhibition at 100 nmol/L. The extent of aggregation after exposure to a shear rate of 10 800 s
−1
for 6 minutes in the presence of 100 nmol/L AR-C69931 MX was 32.4±8.2% (mean±SD), which was significantly lower than the value in the controls of 69.7±9.6% (
P
<0.01). The inhibiting effects of AR-C69931 MX were reversed by exogenous addition of adenosine 5′-diphosphate. Shear-induced VWF binding and P-selectin surface translocation, which occurred in 4696±911 and 5964±784, respectively, of 10 000 measured platelets, was also inhibited by AR-C69931 MX (100 nmol/L) to 1948±528 and 2797±718, respectively (
P
=0.0018 and
P
=0.0009). Microparticle release was similarly inhibited. In a flow chamber experiment, firm platelet attachment on immobilized VWF was inhibited by AR-C69931 MX, whereas transient interaction was not influenced. All the above reactions were completely inhibited by blocking VWF–GP Ibα interaction.

Conclusions

—

We have demonstrated that the stimulation of P2Y
12
is involved in platelet activation initiated by the binding of VWF to GP Ibα induced by a high shear rate.
Serum Elastase Activity, Serum Elastase Inhibitors, and Occurrence of Carotid Atherosclerotic Plaques
Authors: Zureik Mahmoud , Robert Ladislas , Courbon Dominique , Touboul Pierre-Jean , Bizbiz Latifa , Ducimetière Pierre
Published: July 2002

Background
—

In the last decades, interest has increased in the potential deleterious atherogenic effects of some cellular elastase activities. The results of experimental and clinical investigations were inconsistent. In this report, we assessed the associations of serum elastase activity and serum elastase inhibitors with carotid plaque occurrence during the 4-year follow-up in a population of 859 subjects free of coronary heart disease and stroke (age, 59 to 71 years).

Methods and Results
—

Serum elastase activity and serum elastase inhibitors were measured at baseline examination. Carotid B-mode ultrasound examination was performed at baseline and 2 years and 4 years later. The occurrence of carotid plaques in subjects with the lowest serum elastase activity values (quartile 1), in those with the intermediate values (quartiles 2 to 3), and in those with the highest values (quartile 4) was, respectively, 24.6%, 18.9%, and 12.2% (
P
<0.001 for trend). The multivariate odds ratios of carotid plaque occurrence associated with the three groups (adjusted for major known cardiovascular risk factors) were, respectively, 1.00, 0.67 (CI, 0.44 to 1.02;
P
<0.06), and 0.40 (CI, 0.23 to 0.70,
P
<0.001). For serum elastase inhibitors, the occurrence of carotid plaques in quartile 1 (lowest values), quartiles 2 to 3, and quartile 4 (highest values) was, respectively, 11.7%, 18.8%, and 25.2% (
P
for trend<0.001). The corresponding multivariate adjusted odds ratios were 1.00, 1.98 (CI, 1.19 to 3.31,
P
<0.01), and 3.18 (CI, 1.80 to 5.60,
P
<0.001).

Conclusions
—

Low values of serum elastase activity and high values of serum elastase inhibitors were strongly and independently associated with increased 4-year carotid plaque occurrence. Further studies are necessary to elucidate the nature of the associations between elastase parameters and atherosclerosis.
Left Ventricular Thrombus Enhancement After Intravenous Injection of Echogenic Immunoliposomes
Authors: Hamilton Andrew , Huang Shao-Ling , Warnick Drew , Stein Adam , Rabbat Mark , Madhav Taruna , Kane Bonnie , Nagaraj Ashwin , Klegerman Melvin , MacDonald Robert , McPherson David
Published: July 2002

Background

—

Targeted echogenic immunoliposomes (ELIPs) for ultrasound enhancement of atheroma components have been developed. To date, ELIP delivery has been intra-arterial. To determine whether ELIPs can be given intravenously with enhancement of systemic structures, a left ventricular thrombus (LVT) model was developed.

Methods and Results

—

In 6 animals plus 1 dose-ranging animal, the apical coronary arteries were ligated, and an LVT was produced by injecting Hemaseel fibrin adhesive through the apical myocardium. The thrombus was imaged epicardially and transthoracically at 0, 1, 5, and 10 minutes after anti-fibrinogen ELIP injections. The dose of ELIPs was varied. PBS and unconjugated ELIPs were controls. The apical thrombi were easily reproduced and clearly visible with epicardial and transthoracic ultrasound. Enhancement occurred with 2 mg anti-fibrinogen ELIPs and increased with dose. With 8 mg ELIPs, enhancement was different from control within 10 minutes (
P
<0.05). Rhodamine-labeled anti-fibrinogen ELIPs were seen with fluorescence microscopy of the LVT. Blinded viewing detected enhancement by 10 minutes in all animals after anti-fibrinogen ELIPs.

Conclusions

—

We describe an easily reproducible LVT model. Anti-fibrinogen ELIPs delivered intravenously, as a single-step process, rapidly enhance the ultrasound image of a systemic target. This allows for future development of ELIPs as a targeted ultrasound contrast agent.
Losing Their Configural Mind: Amnesic Patients Fail on Transverse Patterning
Authors: Rickard Timothy C. , Grafman Jordan
Published: July 2002

A configural theory of human amnesia is proposed. The theory predicts that amnesic patients will exhibit selective deficits on tasks that normal subjects perform by learning new configurations of stimulus elements. This prediction is supported by results for four amnesic patients who learned a nonconfigural control task but failed to learn the configural transverse patterning task even after extensive practice. Matched normal subjects easily learned both tasks. The theory provides unique and viable accounts of the central results in the human amnesia literature. Relations between the configural approach and other theories are discussed.
Breaking Rotational Symmetry in a Self-Organizing Map Model for Orientation Map Development
Authors: Riesenhuber M. , Bauer H.-U. , Brockmann D. , Geisel T.
Published: July 2002

We analyze the pattern formation behavior of a high-dimensional self-organizing map (SOM) model for the competitive projection of ON-center-type and OFF-center-type inputs to a common map layer. We mathematically show, and numerically confirm, that even isotropic stimuli can drive the development of oriented receptive fields and an orientation map in this model. This result provides an important missing link in the spectrum of pattern formation behaviors observed in SOM models. Extending the model by including further layers for binocular inputs, we also investigate the combined development of orientation and ocular dominance maps. A parameter region for combined patterns exists; corresponding maps show a preference for perpendicular intersection angles between iso-orientation lines and ocularity domain boundaries, consistent with experimental observations.
The Technology and Music of the Nigerian Igbo Ogene Anuka Bell Orchestra
Authors: Nzewi O'dyke
Published: July 2002

The author discusses the Nigerian Igbo Ogene Anuka music style, a complex form using iron bells of the same name. The article addresses the form and content of the music as developed and modified by its master practitioners. The author then investigates the technical processes involved in achieving the distinctive sound quality of the bells-processes in which musical considerations interact significantly.
Investigations into Performance of Minimally Invasive Telesurgery with Feedback Time Delays
Authors: Ottensmeyer Mark P. , Hu Jianjuen , Thompson James M. , Ren Jie , Sheridan Thomas B.
Published: July 2002

This paper describes the testbed telesurgery system that was developed in MIT's Human Machine Systems Laboratory. This system was used to investigate the effects of communication time delays on controller stability and on the performance of surgical tasks.

The system includes a bilateral force-reflecting teleoperator system, interchangeable surgical tools, audio and video communication between the master and slave sites, and methods to generate time delays between the sites. To compensate for the time delays, various control schemes were investigated, leading to the development and selection of fuzzy sliding control (FSC). With a stable teleoperator system, experiments in performing a variety of surgical exercises were conducted. These looked at the performance of a team of a telesurgeon and local assistant given a number of different time-delay scenarios, including synchronous and asynchronous force and audio/video feedback.

The results of the research project include the development of the novel FSC algorithm, data on how time delays degrade performance of surgical tasks, and recommendations on how telesurgery should be performed to accommodate telecommunication time delays.
How Can We Determine if the Sense of Presence Affects Task Performance?
Authors: Welch Robert B.
Published: July 2002

The question of whether the sense of presence in virtual environments (or telepresence with respect to teleoperator systems) is causally related to task performance remains unanswered because the appropriate studies have yet to be carried out. In this brief report, the author describes a strategy for resolving this issue and the results of a pilot study in which this strategy was implemented.
“Real” Presence: How Different Ontologies Generate Different Criteria for Presence, Telepresence, and Virtual Presence
Authors: Mantovani Giuseppe , Riva Giuseppe
Published: July 2002

This article claims that the meaning of presence is closely linked to the concept we have of reality, i.e., to the ontology that we more or less explicitly adopt. Different ontological stances support different criteria for presence, telepresence, and virtual presence. We propose a cultural conception of presence that challenges the current idea that experiencing a real or simulated environment deals essentially with perceiving its “objective” physical features. We reject commonsense ingenuous realism and its dualism opposing external reality and internal ideas. In our perspective, presence in an environment, real or simulated, means that individuals can perceive themselves, objects, and other people not only as situated in an external space but also as immersed in a sociocultural web connecting objects, people, and their interactions. This cultural web—structured by artifacts both physical (e.g., the physical components of the computer networks) and ideal (e.g., the social norms that shape the organizational use of the computer networks)—makes possible communication and cooperation among different social actors by granting them a common reference grid. Environments, real and virtual, are not private recesses but public places for meaningful social interaction mediated by artifacts. Experiencing presence in a social environment such as a shared virtual office requires more than the reproduction of the physical features of external reality; it requires awareness of the cultural web that makes meaningful—and therefore visible—both people and objects populating the environment.
WHAT IF WE HAD NO ACCOUNTS OF SENNACHERIB'S THIRD CAMPAIGN OR THE PALACE RELIEFS DEPICTING HIS CAPTURE OF LACHISH?
Authors: Edelman Diana
Published: July 2002

In spite of the important information contained in the various accounts of Sennacherib's third campaign and the reliefs of his conquest of Lachish, their absence would have little effect upon the recreation of the events of the reign of Hezekiah by historians of Judah. The results of excavations at Tell ed-Duweir/ Lachish and Tel Miqne/Ekron suggest that sometime in the last decades of the eighth century or in the opening decades of the seventh century bce, there was an Assyrian military presence in the Judean shephelah and a ceding of control over the olive yield in the shephelah and highlands of Judah to the Philistines to fuel a newly established regional olive oil industry. When information about the kings who ruled Judah in the period in question is considered, Hezekiah remains the most logical candidate under whom the ceding of territorial control, which would have required Assyrian consent and agency, can be plausibly posited. The main outlines of the history of the period can nevertheless be posited; only the specific nature of the interregional conflict between Judah and Philistia and the specific Assyrian resolution of the conflict cannot be established.
Hermann Diels on the Presocratics: Empedocles' double destruction of the cosmos (Aetius ii 4.8)
Authors: O'Brien Denis
Published: July 2002

Stobaeus records a placitum where Empedocles says that the world is destroyed by the domination in turn of Love and of Strife. The placitum makes perfectly good sense in the context of Empedocles' belief that Love and Strife produce, in turn, a non-cosmic state of total unity (Love) and of total separation (Strife). But for over two hundred years scholars have been unable to hear that simple message. Sturz (1805) emended the text so as to make it fit the non-cyclical interpretation of Empedocles that he had taken over from the pages of Tiedemann (1791). When Diels included Stobaeus' text in his edition of Aetius, in the Doxographi graeci (1879), he failed to remove the emendation, although his own reconstruction of the chapter heading in Aetius made the emendation impossible. Twenty years later, Diels saw the light, and printed Stobaeus' placitum, unemended, in his Poetarum philosophorum fragmenta (1901) and in successive editions of his Fragmente der Vorsokratiker (from 1903 onwards). But Kranz resurrected the emendation in the Nachträge to his sixth edition of the Fragmente der Vorsokratiker (1951). The emended placitum is used again by Uvo Hölscher (1965) to support a non-cyclical interpretation of Empedocles and is repeated in the latest collection of the fragments and testimonia (Brad Inwood, 1992). Hölscher fails to appreciate that the text that he uses to support his reconstruction is merely Sturz's translation into Greek of the non-cyclical interpretation of Empedocles proposed by Tiedemann at the end of the eighteenth century.
DID THE AUTHORS OF THE BOOKS OF KINGS MAKE USE OF ROYAL INSCRIPTIONS?
Authors: Parker Simon
Published: July 2002

In light of several recent claims that the authors of Kings made use of royal inscriptions, this paper reviews the various kinds of evidence bearing on the matter. The first focus of attention is the evidence for the production of royal inscriptions in Israel and Judah: literary (biblical) references as evidence of native belief in such and archaeological (epigraphic) evidence of actual inscriptions. Fragmentary as it is, this evidence supports the claim that at least royal building inscriptions were produced. Second, assuming that the kings of Israel and Judah would have addressed similar subjects on similar occasions to those addressed by neighboring kings in royal inscriptions, the author examines the evidence for the appearance in Kings of material characteristic of the Northwest Semitic royal inscriptions recovered to date from neighbors of Israel and Judah. Here the conclusion is negative - although the study supports the hypothesis of Kings' use of an Israelite king list.
RUSKIN'S MEMORIAL LANDSCAPES
Authors: O'Gorman Francis
Published: July 2002

John Ruskin, on significant public occasions in his later life, affirmed the healthiness of the human imagination that found in nature not divine truths, but human histories. He celebrated as a sign of a community's well being, the capacity of the eye to look at landscape with awareness of its (imagined) history. Perceiving the environment in this way was to enter imaginatively into association with one's own society's past and ancestral heritage, and to recognize a meaningful and personally relevant continuum between the present and history. But when writing his own life history, Ruskin realized with regret that he could not fully memorialise his ancestors because he had been 'profanely' indifferent to their history. Aware of the value of a memorial landscape but importantly detached from his own history, Ruskin sensed himself adrift. But the uneasy dislocation he felt here was more than personal: it was culturally suggestive as a pre-echo of the more dramatically deracinated self, detached from history and community, which characterized modernity's notion of selfhood.
BURROWING BY COMMON VOLES (MICROTUS ARVALIS) IN VARIOUS SOCIAL ENVIRONMENTS
Authors: Dobly Alexandre , Rozenfeld Francine
Published: July 2002

Female common voles live in groups in large burrows whereas males are probably solitary and promiscuous. At high population density, when burrows become a limiting factor, some females are forced to emigrate from their group. To investigate whether these emigrants could share new common burrows with unrelated neighbours, we analysed in the laboratory burrowing and social behaviour in dyads of unrelated wild females before and during their cohabitation. They were compared to wild male dyads. In solitary voles, no sexual difference in burrowing pattern was observed but females built a burrow more quickly than males. In both sexes, the first encounters happened in one of the burrow and were of aggressive nature; during them intruders used burrowing during offensive approaches. While males displayed hierarchy and nested for themselves, females rapidly became friendly and nested together. They reshaped their burrows in response to social nesting and had more complex burrows than solitary females or intolerant males. We may conclude that in common voles at least unrelated non breeding females may contribute to the formation of social groups. To investigate whether, within a matriarchal group, females may co-operate with their own daughters in building a new common burrow, we analysed burrowing behaviour in dyads comprising either an experienced wild mother with one of her naive daughters or two naive familiar daughters. No co-operative behaviour could be detected but experience in burrowing speeded up the building. The results strongly suggest that, within a short time, young females may improve their burrowing.
SCAN SAMPLING AND WATERFOWL ACTIVITY BUDGET STUDIES: DESIGN AND ANALYSIS CONSIDERATIONS
Authors: Hepworth Graham , Hamilton Andrew
Published: July 2002

Scan sampling is a common technique used to quantify the activities of animals, including waterfowl. When large numbers are present, it is often impractical to record the activities of each individual, and sub-sampling is employed. We present a method for the design and analysis of scan sampling studies involving sub-sampling, based on an actual study of waterfowl activity on a waste stabilisation pond. The design we propose avoids subjectivity in the selection of individuals, is truly random rather than haphazard, and is adaptable to other situations. It allows for the population on each sampling occasion to be divided into separate strata with samples taken from each. The method of analysis addresses the statistical issues arising from such designs. In estimating the proportion of individuals engaged in an activity, it uses the information from observations in which some of the individuals are counted but their activities not recorded, and estimates the sampling variance introduced by sub-sampling. In comparing the mean proportions for different levels of a factor, such as time of day, the method uses restricted maximum likelihood (REML), an algorithm which can account for the sampling variance as well as for missing data. It is anticipated that the methods described in this paper will assist researchers using the scan sampling technique, or workers in any discipline where sampling characteristics are similar.