bluuebunny/crossref_metadata_2025 huggingface dataset:
An introduction to assertional reasoning for concurrent systems
Authors: Shankar A. Udaya
Published: July 2002

This is a tutorial introduction to assertional reasoning based on temporal logic. The objective is to provide a working familiarity with the technique. We use a simple system model and a simple proof system, and we keep to a minimum the treatment of issues such as soundness, completeness, compositionality, and abstraction. We model a concurrent system by a state transition system and fairness requirements. We reason about such systems using Hoare logic and a subset of linear-time temporal logic, specifically, invariant assertions and leads-to assertions. We apply the method to several examples.
Fast floating-point processing in Common Lisp
Authors: Fateman Richard J. , Broughan Kevin A. , Willcock Diane K. , Rettig Duane
Published: July 2002

Lisp, one of the oldest higher-level programming languages, has rarely been used for fast numerical (floating-point) computation. We explore the benefits of Common Lisp, an emerging new language standard with some excellent implementations, for numerical computation. We compare it to Fortran in terms of the speed of efficiency of generated code, as well as the structure and convenience of the language. There are a surprising number of advantages to Lisp, especially in cases where a mixture of symbolic and numeric processing is needed.
Little engines that could
Authors: Dedrick J. L. , Goodman S. E. , Kraemer K. L.
Published: July 2002

How do very small countries, here defined as having fewer than 10 million people, find places for themselves in the information technologies (IT) arena? Does success require accommodation in the global IT regime that often seems dominated by the U.S. and Japan? Do the little countries scurry around, like birds among the lions and other predators looking for scraps? Are they relegated to second tier “appropriate technologies,” or do they operate in the mainstream?
Space optimization in deductive databases
Authors: Srivastava Divesh , Sudarshan S. , Ramakrishnan Raghu , Naughton Jeffrey F.
Published: July 2002

In the bottom-up evaluation of logic programs and recursively defined views on databases, all generated facts are usually assumed to be stored until the end of the evaluation. Discarding facts during the evaluation, however, can considerably improve the efficiency of the evaluation: the space needed to evaluate the program, the I/O costs, the costs of maintaining and accessing indices, and the cost of eliminating duplicates may all be reduced. Given an evaluation method that is sound, complete, and does not repeat derivation steps, we consider how facts can be discarded during the evaluation without compromising these properties. We show that every such space optimization method has certain components, the first to ensure soundness and completeness, the second to avoid redundancy (i.e., repetition of derivations), and the third to reduce “fact lifetimes” (i.e., the time period for which each fact must be retained during evaluation). We present new techniques based on providing bounds on the number of derivations and uses of facts, and using monotonicity constraints for each of the first two components, and provide novel synchronization techniques for the third component of a space optimization method. We describe how techniques for each of the three components can be combined in practice to obtain a space optimization method for a program. Our results are also of importance in applications such as sequence querying, and in active databases where triggers are defined over multiple “events.”
Explicit OR-dispersers with polylogarithmic degree
Authors: Saks Michael , Srinivasan Aravind , Zhou Shiyu
Published: July 2002

An (
N, M, T
)-OR-disperser is a bipartite multigraph
G
=(
V, W, E
) with |
V
| =
N
, and |
W
| =
M
, having the following expansion property: any subset of
V
having at least
T
vertices has a neighbor set of size at least
M
/2. For any pair of constants ξ, λ, 1 ≥ ξ > λ ≥ 0, any sufficiently large
N
, and for any
T
≥ 2

(log
N
)

M
≤ 2

(log
N
)
λ

, we give an explicit elementary construction of an (
N, M, T
)-OR-disperser such that the out-degree of any vertex in
V
is at most polylogarithmic in
N
. Using this with known applications of OR-dispersers yields several results. First, our construction implies that the complexity class Strong-RP defined by Sipser, equals RP. Second, for any fixed η > 0, we give the first polynomial-time simulation of RP algorithms using the output of any “η-minimally random” source. For any integral
R
> 0, such a source accepts a single request for an
R
-bit string and generates the string according to a distribution that assigns probability at most 2

−R
η

to any string. It is minimally random in the sense that any weaker source is insufficient to do a black-box polynomial-time simulation of RP algorithms.
On contention resolution protocols and associated probabilistic phenomena
Authors: MacKenzie P. D. , Plaxton C. G. , Rajaraman R.
Published: July 2002

Consider an on-line scheduling problem in which a set of abstract processes are competing for the use of a number of resources. Further assume that it is either prohibitively expensive or impossible for any two of the processes to directly communicate with one another. If several processes simultaneously attempt to allocate a particular resource (as may be expected to occur, since the processes cannot easily coordinate their allocations), then none succeed. In such a framework, it is a challenge to design efficient contention resolution protocols.

Two recently-proposed approaches to the problem of PRAM emulation give rise to scheduling problems of the above kind. In one approach, the resources (in this case, the shared memory cells) are duplicated and distributed randomly. We analyze a simple and efficient deterministic algorithm for accessing some subset of the duplicated resources. In the other approach, we analyze how quickly we can access the given (nonduplicated) resource using a simple randomized strategy. We obtain precise bounds on the performance of both strategies. We anticipate that our results with find other applications.
Automatic modeling of file system workloads using two-level arrival processes
Authors: Ware Peter P. , Page Thomas W. , Nelson Barry L.
Published: July 2002

This article describes a method for analyzing, modeling, and simulating a two-level arrival-counting process. This method is particlarly appropriate when the number of independent processes is large, as is the case in our motivating application which requires analyzing and representing computer file system trace data for activity on nearly 8,000 files. The method is also applicable to network trace data characterizing communication patterns between pairs of computers. We apply cluster analysis to separate the arrival process into groups or bursts of activity on a file. We then characterize the arrival procss in terms of the time between bursts of activity on file, the time between file events within bursts, and the number of events in a burst. Finally, we model these three components individually, then reassemble the results to produce a synthetic trace generator. In order to gauge the effectiveness of this method, we use synthetically generated (simulated) trace data produced in this way to drive a discrete-event simulation of a distributed replicated file system. We compare the results of the simulation driven by the synthetic trace with the same simulation driven by the original trace data, and conclude that the synthetic data capture the essential characteristics of the empirical trace.
Rate analysis for embedded systems
Authors: Mathur Anmol , Dasdan Ali , Gupta Rajesh K.
Published: July 2002

Embedded systems consist of interacting components that are required to deliver a specific functionality under constraints on execution rates and relative time separation of the components. In this article, we model an embedded system using concurrent processes interacting through synchronization. We assume that there are rate constraints on the execution rates of processes imposed by the designer or the environment of the system, where the execution rate of a process is the number of its executions per unit time. We address the problem of computing bounds on the execution rates of processes constituting an embedded system, and propose an interactive rate analysis framework. As part of the rate analysis framework we present an efficient algorithms for checking the consistency of the rate constraints. Bounds on the execution rate of each process are computed using an efficient algorithm based on the relationship between the execution rate of a process and the maximum mean delay cycles in the process graph. Finally, if the computed rates violate some of the rate constraints, some of the processes in the system are redesigned using information from the rate analysis step. This rate analysis framework is implemented in a tool called RATAN. We illustrate by an example how RATAN can be used in an embedded system design.
Design and analysis of dynamic Huffman codes
Authors: Vitter Jeffrey Scott
Published: July 2002

A new one-pass algorithm for constructing dynamic Huffman codes is introduced and analyzed. We also analyze the one-pass algorithm due to Faller, Gallager, and Knuth. In each algorithm, both the sender and the receiver maintain equivalent dynamically varying Huffman trees, and the coding is done in real time. We show that the number of bits used by the new algorithm to encode a message containing
t
letters is <
t
bits more than that used by the conventional two-pass Huffman scheme, independent of the alphabet size. This is best possible in the worst case, for any one-pass Huffman method. Tight upper and lower bounds are derived. Empirical tests show that the encodings produced by the new algorithm are shorter than those of the other one-pass algorithm and, except for long messages, are shorter than those of the two-pass method. The new algorithm is well suited for on-line encoding/decoding in data networks and for tile compression.
Optimizing computations for effective block-processing
Authors: Lalgudi Kumar N. , Papaefthymiou Marios C. , Potkonjak Miodrag
Published: July 2002

Block-processing can decrease the time and power required to perform any given computation by simultaneously processing multiple samples of input data. The effectiveness of block-processing can be severely limited, however, if the delays in the dataflow graph of the computation are placed suboptimally. In this paper we investigate the application of retiming for improving the effectiveness of block-processing in computations. In particular, we consider the
k-delay problem
: Given a computation dataflow graph and a positive integer
k
, we wish to compute a retimed computation graph in which the original delays have been relocated so that
k
data samples can be processed simultaneously and fully regularly. We give an exact integer linear programming formulation for the
k
-delay problem. We also describe an algorithm that solves the
k
-delay problem fast in practice by relying on a set of necessary conditions to prune the search space. Experimental results with synthetic and random benchmarks demonstrate the performance improvements achievable by block-processing and the efficiency of our algorithm.
First-order conditional logic for default reasoning revisited
Authors: Friedman Nir , Halpern Joseph Y. , Koller Daphne
Published: July 2002

Conditional logics
play an important role in recent attempts to formulate theories of default reasoning. This paper investigates first-order conditional logic. We show that, as for first-order probabilistic logic, it is important not to confound
statistical
conditionals over the domain (such as “most birds fly”), and
subjective
conditionals over possible worlds (such as “I believe that Tweety is unlikely to fly”). We then address the issue of ascribing semantics to first-order conditional logic. As in the propositional case, there are many possible semantics. To study the problem in a coherent way, we use
plausibility structures
. These provide us with a general framework in which many of the standard approaches can be embedded. We show that while these standard approaches are all the same at the propositional level, they are significantly different in the context of a first-order language. Furthermore, we show that plausibilities provide the most natural extension of conditional logic to the first-order case:we provide a sound and complete axiomatization that contains only the KLM properties and standard axioms of first-order modal logic. We show that most of the other approaches have additional properties, which result in an inappropriate treatment of an infinitary version of the
lottery paradox
.
An automatic grading scheme for simple programming exercises
Authors: Hext J. B. , Winings J. W.
Published: July 2002

A discussion is given of alterations that were made to a typical university operating system to record the results of programming exercises in three different languages, includeing assembly language. In this computer-controlled grading scheme provision is made for testing with programmer-supplied data and for final runs with system-supplied data. Exercises run under the scheme may be mixed with other programs, and no special recognition of exercises by the operators is necessary.
Over all computation control and labelling
Authors: Holt Anatol
Published: July 2002

The primary function of computer installation is (as everyone knows) to solve useful problems. The programs that accomplish such solutions are called
production programs
, and when they are applied to a particular set of data and run on the computer the computer is engaged in a
production run
.
What Makes the Human Brain Different?
Authors: Deacon Terrence W.
Published: July 2002

Despite decades of research that has revolutionized the neurosciences, efforts to explain the major features of human brain evolution are still mostly based on superficial gross neuroanatomical features (e.g. size, sulcal patterns) and on theories of selection for high-level functions that lack precise neurobiological predictions (e.g. general intelligence, innate grammar). Beyond its large size we still lack an account of what makes a human brain different. However, advances in comparative neuroanatomy, developmental biology, and genetics have radically changed our understanding of brain development. These data challenge classic ideas about brain size, intelligence, and the addition of new functions, such as language, and they provide tools with which we can test hypotheses about how human brains diverge from other primate brains.
Channeling of Substrates and Intermediates in Enzyme-Catalyzed Reactions
Authors: Huang Xinyi , Holden Hazel M. , Raushel Frank M.
Published: July 2002

▪ Abstract  The three-dimensional structures of tryptophan synthase, carbamoyl phosphate synthetase, glutamine phosphoribosylpyrophosphate amidotransferase, and asparagine synthetase have revealed the relative locations of multiple active sites within these proteins. In all of these polyfunctional enzymes, a product formed from the catalytic reaction at one active site is a substrate for an enzymatic reaction at a distal active site. Reaction intermediates are translocated from one active site to the next through the participation of an intermolecular tunnel. The tunnel in tryptophan synthase is ∼25 Å in length, whereas the tunnel in carbamoyl phosphate synthetase is nearly 100 Å long. Kinetic studies have demonstrated that the individual reactions are coordinated through allosteric coupling of one active site with another. The participation of these molecular tunnels is thought to protect reactive intermediates from coming in contact with the external medium.
Magnetohydrodynamics in Rapidly Rotating spherical Systems
Authors: Zhang Keke , Schubert Gerald
Published: July 2002

▪ Abstract  Recent developments in the study of buoyancy-driven convection, magnetoconvection, and convection-driven dynamos in rapidly rotating spherical systems, with application to the fluid parts of the metallic cores of the Earth and other planets and satellites, are reviewed. While the fluid motions driven by convection generate and sustain magnetic fields by magnetohydrodynamic dynamo processes, the pattern and strength of the convective motions that control dynamo action are critically influenced by the combined and inseparable effects of rotation, magnetic fields, and spherical geometry. Emphasis is placed on the key dynamic feature of rotating spherical magnetohydrodynamics—the interaction between the Coriolis and Lorentz forces and the resulting effect on convection and magnetohydrodynamic processes. It is shown that the small value of the Ekman number, a result of rapid rotation and small viscosity in the fluid parts of planetary cores, causes severe difficulties in modeling planetary dynamos. There exist huge disparities, as a direct consequence of a small Ekman number, in the spatial, temporal, and amplitude scales of a convection-driven dynamo. The use of hyperviscosity removes these difficulties, but at the same time it alters the key dynamics in a fundamental and undesirable way. A convection-driven dynamo solution in rotating spherical systems at a sufficiently small Ekman number that is dynamically relevant to planetary fluid cores is yet to be achieved and remains a great challenge.
CLASS II ANTIGENS AND DISEASE SUSCEPTIBILITY
Authors: Nepom, M.D., Ph.D Gerald T.
Published: July 2002

▪ Abstract  The role for HLA typing in autoimmune disease is changing with the recognition that HLA markers can identify patients with poor prognosis in some autoimmune disease. Aggressive therapeutic intervention in patients with such HLA prognostic markers has the potential to improve or prevent progressive disease outcomes in a select group of patients.
HIGH-ALTITUDE PULMONARY EDEMA: Current Concepts
Authors: Hultgren, M.D Herbert N.
Published: July 2002

▪ Abstract  High-altitude pulmonary edema (HAPE) occurs in unacclimatized individuals who are rapidly exposed to altitudes in excess of 2450 m. It is commonly seen in climbers and skiers who ascend to high altitude without previous acclimatization. Initial symptoms of dyspnea, cough, weakness, and chest tightness appear, usually within 1–3 days after arrival. Common physical signs are tachypnea, tachycardia, rales, and cyanosis. Descent to a lower altitude, nifedipine, and oxygen administration result in rapid clinical improvement. Physiologic studies during the acute stage have revealed a normal pulmonary artery wedge pressure, marked elevation of pulmonary artery pressure, severe arterial unsaturation, and usually a low cardiac output. Pulmonary arteriolar (precapillary) resistance is elevated. A working hypothesis of the etiology of HAPE suggests that hypoxic pulmonary vasoconstriction is extensive but not uniform. The result is overperfusion of the remaining patent vessels with transmission of the high pulmonary artery pressure to capillaries. Dilatation of the capillaries and high flow results in capillary injury, with leakage of protein and red cells into the alveoli and airways. HAPE represents one of the few varieties of pulmonary edema where left ventricular filling pressure is normal.
THE EVALUATION OF DIAGNOSTIC TESTS: Principles, Problems, and New Developments
Authors: Sox, M.D Harold C.
Published: July 2002

▪ Abstract  This article describes the use of probability in reasoning about diagnostic test results and the importance of accurate measures of test performance. Most studies of test performance are retrospective analyses of unplanned observations. Retrospective studies are likely to result in biased estimates of test performance. This article shows how to adjust for biases in the results of retrospective studies and how to design a prospective study that will accurately measure the sensitivity and specificity of a test.
MANAGEMENT OF BENIGN PROSTATIC HYPERPLASIA
Authors: Barry, MD M. , Roehrborn, MD C.
Published: July 2002

▪ Abstract  Benign prostatic hyperplasia (BPH) is a common cause of morbidity among older men. Primary care physicians need to develop expertise in its management. The causes of BPH are unknown; aging and the presence of male androgens are the dominant risk factors. Obtaining a medical history is a key step in assessing whether lower urinary tract symptoms are due to BPH or to some other process. A reliable and valid seven-item questionnaire has been developed to objectively assess symptom severity. A focused physical examination including a digital rectal exam should be performed, as well as a urinalysis and serum creatinine. Optional tests include uroflowmetry, post-void residual urine, and prostate-specific antigen measurements. BPH is treated primarily to improve the quality, rather than increase the quantity, of life. Optimal decisions about treatment are best made by a clinician and an informed patient working together.
Pain Genes?: Natural Variation and Transgenic Mutants
Authors: Mogil Jeffrey S. , Yu Lei , Basbaum Allan I.
Published: July 2002

Like many other complex biological phenomena, pain is starting to be studied at the level of the gene. Advances in molecular biological technology have allowed the cloning, mapping, and sequencing of genes, and also the ablility to disrupt their function entirely (i.e. via transgenic knoockouts). With these new tools at hand, pain researchers have begun in earnest the task of defining (a) which of the 70,000– 150,000 mammalian genes are involved in the mediation of pain, and (b) which of the pain-relevant genes are polymorphic, contributing to both natural variation in responses and pathology. Although there are only a few known examples in which single gene mutations in humans are associated with pain conditions (e.g. an inherited form of migraine and congenital insensitivity to pain), it is likely that others will be identified. Concurrently, a variety of genes have been implicated in both the transmission and control of “pain” messages in animals. The present review summarizes current progress to these ends, focusing on both transgenic (gene→behavior) and classical genetic (behavior→gene) approaches in both humans and laboratory mice.
MOLECULAR INSIGHTS INTO CARDIAC DEVELOPMENT
Authors: Sucov Henry M.
Published: July 2002

▪ Abstract  Recent discoveries have led to a greater appreciation of the diverse mechanisms that underlie cardiac morphogenesis. Genetic strategies (primarily gene targeting approaches in mice) have significantly broadened research in cardiovascular developmental biology by illuminating new pathways involved in heart development and by allowing the genetic evaluation of pathways that have previously been implicated in these events. Advances have also been made using biochemical and cell- and tissue-based approaches. This review summarizes the author's interpretation of current trends in the effort to understand the molecular basis of cardiac development, with an emphasis on insights obtained from genetic models.
REGULATION OF CERAMIDE PRODUCTION AND APOPTOSIS
Authors: Kolesnick Richard N. , Krönke Martin
Published: July 2002

▪ Abstract  Ceramide is a sphingosine-based lipid signaling molecule that regulates cellular differentiation, proliferation, and apoptosis. The emerging picture suggests that coupling of ceramide to specific signaling cascades is both stimulus and cell-type specific. Ceramide action is determined within the context of other stimuli and by the subcellular topology of its production. Here, we discuss the pathways of ceramide generation and the interaction of ceramide with caspases and other apoptotic signaling cascades.
Urinary Protein and Essential Hypertension in Black and in White People
Authors: Chelliah Rajani , Sagnella Giuseppe A. , Markandu Nirmala D. , MacGregor Graham A.
Published: July 2002

The objectives of this work were to examine the association between urinary protein and blood pressure and to compare the pattern of urinary protein excretion with essential hypertension in people of European origin (whites) and in people of African or African-Caribbean origin (blacks) living in southwest London, United Kingdom. In the groups as a whole, there were no significant differences in total urinary protein excretion between blacks and whites (geometric means [95% CI]: 94.0 [85.9 to 102.9] mg/24h for the blacks [n=151] and 102.1 [96.1 to 108.4] mg/24h for the whites [n= 219]). There were also no significant differences between blacks and whites in urinary albumin (6.5 [4.9 to 8.5] mg/24h for the blacks [n=97] and 7.1 [5.6 to 9.0] mg/24h for the whites [n=123]). In both groups, those with essential hypertension displayed a significantly raised urinary protein excretion (1.21-fold higher for the blacks and 1.19-fold higher for the whites) and albumin excretion (1.69-fold higher for the blacks and 2.40-fold higher for the whites). Urinary transferrin excretion measured in a subgroup of 67 subjects was also raised in those with essential hypertension (3.22-fold higher in the blacks and 2.76-fold higher in the whites). Examination of urinary proteins by SDS-PAGE did not identify any pattern consistent with a reduction in renal tubular protein reabsorption in those with essential hypertension. These results suggest that the increase in protein excretion in essential hypertension could be due, at least in part, to an increase in glomerular protein ultrafiltration.
Second Harmonic Imaging of the Human Brain
Authors: Harrer Judith U. , Klötzsch Christof
Published: July 2002

Background and Purpose

—

Second harmonic imaging (SHI) is a novel ultrasound technique that allows the evaluation of brain tissue perfusion. The purpose of this study was to assess normal cerebral echo contrast characteristics in 3 regions of interest (ROIs) in the transverse axial and coronal insonation planes through the temporal bone window.

Materials and Methods

—

SHI examinations were performed in 25 patients without cerebrovascular disease (aged 50±19 years) in a transverse axial and a coronal diencephalic insonation plane through the temporal bone window. After intravenous administration of 2.5 g (400 mg/mL) of a galactose-based echo contrast agent, 62 time-triggered images with a transmission rate of 1 frame per 2.5 seconds were recorded for offline analysis. Time-intensity curves, including peak intensity (PI) (dB) and positive gradient (PG) (dB/s), were calculated to quantify ultrasound intensity in 3 different ROIs in both planes of the following sections: the thalamus (ROI
thal
), the lentiform nucleus (ROI
ncl
), and the area supplied by the middle cerebral artery (ROI
mca
).

Results

—

Characteristic time-intensity curves with high PIs and steep PGs were recorded in each ROI. Statistical analysis of the aforementioned parameters showed no significant difference for comparison of the 3 ROIs in the transverse axial versus the coronal insonation plane. Comparison of different ROIs in the transverse axial insonation plane revealed that PI was significantly higher in ROI
thal
than in ROI
mca
(7.8 versus 5.5 dB;
P
<0.05) and significantly higher in ROI
ncl
than in ROI
thal
(9.3 versus 7.8 dB;
P
<0.05). In contrast, PG was comparable in ROI
thal
and in ROI
mca
(0.21 versus 0.25 dB/s;
P
=0.42).

Conclusions

—

SHI is a promising technique for the evaluation of cerebral parenchymal perfusion. Comparison of the transverse axial and coronal insonation planes shows similar time-intensity curves with comparable values for PIs and PGs. Coronal insonation allows the evaluation of perfusion abnormalities near the vertex and skull base, areas that cannot be depicted in the transverse axial plane. Comparison of the different ROIs indicates that the PG is a more robust and reliable parameter than the PI.
Theta Oscillations and Human Navigation: A Magnetoencephalography Study
Authors: Araújo Dráulio B. de , Baffa Oswaldo , Wakai Ronald T.
Published: July 2002

Magnetoencephalography (MEG) was used to study alpha and theta activity while subjects navigated through a computer-generated virtual reality town. The subjects were first allowed to explore the environment freely. They then had to navigate from a starting point to a destination, knowing that an obstruction would appear at one of several possible locations along the main route and force them to take a detour. Spatiotemporal analysis of the theta and alpha bands were performed (1) prior to the start of navigation, (2) from the start of navigation until the obstruction was encountered, (3) during the time subjects were contemplating a detour and were not navigating, and (4) from the resumption of navigation until the destination was reached. In all subjects, theta power was strongest during the two periods of navigation. The peak frequency of the oscillations was approximately 3.7 Hz. Control studies consisted of a motor task similar to that required for navigation, passive viewing of a tour through the same virtual reality town, and a mental concentration task. No consistent increases in theta power were seen in the MEG during any of the control tasks. The results suggest an association between theta rhythm and the performance of navigational tasks in humans.
The von Restorff Effect in Visual Object Recognition Memory in Humans and Monkeys: The Role of Frontal/Perirhinal Interaction
Authors: Parker Amanda , Wilding Edward , Akerman Colin
Published: July 2002

This study reports the development of a new, modified delayed matching to sample (DMS) visual recognition memory task that controls the relative novelty of test stimuli and can be used in human and nonhuman primates. We report findings from normal humans and unoperated monkeys, as well as three groups of operated monkeys. In the study phase of this modified paradigm, subjects studied lists of two-dimensional visual object stimuli. In the test phase each studied object was presented again, now paired with a new stimulus (a foil), and the subject had to choose the studied item. In some lists one study item (the novel or isolate item) and its associated foil differed from the others (the homogenous items) along one stimulus dimension (color). The critical experimental measure was the comparison of the visual object recognition error rates for isolate and homogenous test items.

This task was initially administered to human subjects and unoperated monkeys. Error rates for both groups were reliably lower for isolate than for homogenous stimuli in the same list position (the von Restorff effect). The task was then administered to three groups of monkeys who had selective brain lesions. Monkeys with bilateral lesions of the amygdala and fornix, two structures that have been proposed to play a role in novelty and memory encoding, were similar to normal monkeys in their performance on this task. Two further groups— with disconnection lesions of the perirhinal cortex and either the prefrontal cortex or the magnocellular mediodorsal thalamus—showed no evidence of a von Restorff effect. These findings are not consistent with previous proposals that the hippocampus and amygdala constitute a general novelty processing network. Instead, the results support an interaction between the perirhinal and frontal cortices in the processing of certain kinds of novel information that support visual object recognition memory.
A Note on the Decomposition Methods for Support Vector Regression
Authors: Liao Shuo-Peng , Lin Hsuan-Tien , Lin Chih-Jen
Published: July 2002

The dual formulation of support vector regression involves two closely related sets of variables. When the decomposition method is used, many existing approaches use pairs of indices from these two sets as the working set. Basically, they select a base set first and then expand it so all indices are pairs. This makes the implementation different from that for support vector classification. In addition, a larger optimization subproblem has to be solved in each iteration. We provide theoretical proofs and conduct experiments to show that using the base set as the working set leads to similar convergence (number of iterations). Therefore, by using a smaller working set while keeping a similar number of iterations, the program can be simpler and more efficient.
Eric Bentley: On Hero Worship and Degradation
Authors: Nesmith N. Graham
Published: July 2002

Over the past half-century, Bentley has done just about everything in the theatre as a critic, theorist, performer, playwright, and translator. In this wide-ranging interview, he offers opinions on Broadway, nontraditional casting, gays, Brecht—and lots of other topics.
Occlusion Culling in Large Virtual Environments
Authors: Bormann Karsten
Published: July 2002

In this paper, occlusion testing in very large virtual environments is discussed from two perspectives: a theoretical one, discussing occlusion culling in relation to detail elision (level of detail), and a practical one, relating to an adaptive occlusion-culling algorithm developed in this paper.

The theoretical perspective formally demonstrates the efficiency of detail elision in the face of real-world-like environments. It further shows the utility of using detail elision not only to lower the triangle count of individual objects but also to lower the load on the scene graph traversal algorithm. Finally, the results indicate that, even in open environments, one needs occlusion culling and that approaches based on choosing only a few good (convex) occluders are insufficient in this case.

Practically, the theoretical perspective is reflected in the development of an occlusion-culling algorithm based on a marriage of the frustum-slicing approach to view frustum culling and hierarchical occlusion maps (HOMs). The resulting algorithm is much simpler than the original HOM algorithm, requires little pre-processing, and integrates detail elision with the occlusion-culling algorithm in a natural way. The approach is well suited for use with large, complex models with a long mean free line of sight (“the great outdoors”), models for which it is not feasible to construct, or search, a database of occluders to be rendered in each frame. The algorithm is tested for such large models, and results show that frame rates tend to converge as the geometrical complexity of the model increases.
Opium and Sexuality in late Qing Fiction
Authors: McMahon Keith
Published: July 2002

This article examines opium smoking in two gendered contexts of the late Qing, as an activity among socializing men and in situations between men and women. The method is to use fiction to ask how male and female smokers differed and in general to show how opium came to symbolize an uncanny and ominous disruption of the social fabric. In terms of gender, the obscene enjoyment of the female smoker was exponentially more threatening in the prohibitionist's eyes than that of the male. As the sign of an unprecedented type of pleasure, opium addiction threatened to denaturalize the boundaries of cultural as well as gender identity.
JUDAH'S COVENANT WITH DEATH (ISAIAH XXVIII 14-22)
Authors: Blenkinsopp Joseph
Published: July 2002

The prophetic diatribe in Isa. xxviii 7-22 is directed against the Judean political and religious leadership anxiously seeking an alliance with Egypt of the twenty-fifth (Nubian) dynasty shortly before the Assyrian punitive campaign of 701 B.C. The opponents are accused of entering into a covenant with Death and Sheol. It is suggested that the covenant is represented as made with the Canaanite deity Mot (mōtu), rather than with Molech, in the expectation that Mot would take up their cause against his adversary Hadad, personification of the ô ô p of xxviii 15, 18, thus enabling them to survive the anticipated Assyrian attack. Isa. xxviii 7-8 suggests the possibility that the ceremony by which the pact was sealed, reminiscent of the Ugaritic texts KTU I.114, is represented as a parody of the tradition about covenant making at Sinai represented by Exod. xxiv 9 11.
IMMANENT DUALISM AS AN ALTERNATIVE TO DUALISM AND MONISM: THE WORLD VIEW OF MAX WEBER
Authors: Steiner-Aeschliman Sherrie
Published: July 2002

Exploration of the roots of accumulating environmental degradation has reached to the very foundations of Western civilization. The dominant critiques of these foundations primarily focus on two cosmologies: monism and dualism. The purpose of this paper is to examine these foundations from a Weberian perspective and to offer a little known alternative: immanent dualism. This alternative cosmology suggests that religion could help reorganize late industrial capitalism.
X- ray photoelectron spectroscopic study of layer charge magnitude in micas and illite-smectite clays
Authors: Johns W. D. , Gier S.
Published: July 2002

X-ray photoelectron spectroscopy (XPS) was used to determine the surface-charge magnitude and distribution for some micas and high-illite I-S clays. Based on predictable layer by layer atomic ratios for margarite, muscovite and sericite it was possible to establish an escape depth of ∼15 Å for photoelectrons. After the replacement of surface ions by Ba2+, interlayer ion (Ca, K, Na)/Ba ratios are a measure of the relative layer charges on external surfaces and the first internal interlayer. These ratios can be used to assign charge magnitudes and ascertain layer charge asymmetry when it occurs. The O/Ba ratios determined by XPS serve the same purpose. Diagenetic I-S from the Vienna Basin gives an XPS-determined symmetrical layer charge of 0.41; in a similar clay from the Gulf Coast sequence, the outer surface is smectitic, with an external charge of 0.21, in contrast to an opposing silica layer with a charge of 0.31.
Use of pyrite microfabric as a key to tectono-thermal evolution of massive sulphide deposits – an example from Deri, southern Rajasthan, India
Authors: Tiwary Anju , Deb Mihir , Cook Nigel J.
Published: July 2002

Pyrite is an ubiquitous constituent of the Proterozoic massive sulphide deposit at Deri, in the South Delhi Fold Belt of southern Rajasthan. Preserved pyrite microfabrics in the Zn-Pb-Cu sulphide ores of Deri reveal a polyphase growth history of the iron sulphide and enable the tectono-thermal evolution of the deposit to be reconstructed.

Primary sedimentary features in Deri pyrites are preserved as compositional banding. Regional metamorphism from mid-greenschist to low amphibolite facies is recorded by various microtextures of pyrite. Trails of fine grained pyrite inclusions within hornblende porphyroblasts define S1-schistosity. Pyrite boudins aligned parallel to S1 mark the brittle–ductile transformation of pyrite during the earliest deformation in the region. Isoclinal to tight folds (F1 and F2) in pyrite layers relate to a ductile deformation stage during progressive regional metamorphism. Peak metamorphic conditions around 550°C, an estimation supported by garnet–biotite thermometry, resulted in annealing of pyrite grains, while porphyroblastic growth of pyrite (up to 900 µm) took place along the retrogressive path. Brittle deformation of pyrite and growth of irregular pyritic mass around such fractured porphyroblasts characterize the waning phase of regional metamorphism. A subsequent phase of stress-free, thermal metamorphism is recorded in the decussate and rosette textures of arsenopyrite prisms replacing irregular pyritic mass. Annealing of such patchy pyrite provides information regarding the temperature conditions during this episode of thermal metamorphism which is consistent with the hornblendehornfels facies metamorphism interpreted from magnetite–ilmenite geothermometry (550°C) and sphalerite geobarometry (3.5 kbar). A mild cataclastic deformation during the penultimate phase produced microfaults in twinned arsenopyrite prisms.
Human skin–derived mast cells can proliferate while retaining their characteristic functional and protease phenotypes
Authors: Kambe Naotomo , Kambe Michiyo , Kochan Jarema P. , Schwartz Lawrence B.
Published: July 2002

Human mast cells in adult tissues have been thought to have limited, if any, proliferative potential. The current study examined mast cells obtained from adult skin and cultured in serum-free medium with recombinant human stem cell factor. During the first 4 weeks of culture, the percentages of mast cells increased from 10 to almost 100. After 8 weeks, a 150-fold increase in the number of mast cells was observed. When freshly dispersed mast cells were individually sorted onto human fibroblast monolayers and cultured for 3 weeks, one or more mast cells were detected in about two thirds of the wells, and in about two thirds of these wells the surviving mast cells showed evidence of proliferation, indicating most mast cells in skin can proliferate. Such mast cells all expressed high surface levels of Kit and FcεRI, each of which were functional, indicating IgE was not required for FcεRI expression on mast cells. Such mast cells also retained the MCTC protease phenotype of mast cells that normally reside in the dermis. After 4 to 8 weeks of culture these mast cells degranulated in response to substance P and compound 48/80, characteristics of skin-derived mast cells that persist outside of the cutaneous microenvironment.
Gastric marginal zone B-cell lymphomas of MALT type develop along 2 distinct pathogenetic pathways
Authors: Starostik Petr , Patzner Jochen , Greiner Axel , Schwarz Stephan , Kalla Jörg , Ott German , Müller-Hermelink Hans Konrad
Published: July 2002

Low-grade marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type can transform into high-grade diffuse large B-cell lymphoma (DLBCL). Up to 60% of the MALT lymphomas contain the recently described t(11;18). However, this translocation has not been detected in any DLBCL so far. To elucidate the pathogenesis of these tumors, microsatellite screening of 24 gastric MALT lymphomas was performed and the results were compared with aberrations detected in a previous study on gastric DLBCL. The most frequent aberration, found in 21% of the MALT lymphomas that were exclusively t(11;18)-negative cases, was amplification of the 3q26.2-27 region (harboring the locus of the BCL6 gene). Allelic imbalances in regions 3q26.2-27, 6q23.3-25, 7q31, 11q23-24, and 18q21 were shared by both MALT lymphoma and DLBCL. Loss of heterozygosity in regions 5q21 (APC gene locus), 9p21 (INK4A/ARF), 13q14 (RB), and 17p13(p53) and allelic imbalances in 2p16, 6p23, and 12p12-13 occurred exclusively in DLBCL. Only one of 10 t(11;18)-positive MALT lymphomas showed an additional clonal abnormality. These tumors thus display features of a clonal proliferation characterized by the presence of the t(11;18). However, they only rarely display secondary aberrations and do not seem to transform into DLBCL. In contrast, t(11;18)-negative MALT lymphomas show numerous allelic imbalances—some of them identical with aberrations seen in DLBCL—suggesting that this group is the source of tumors eventually transforming into high-grade DLBCL.
Adhesion of human platelets to serum amyloid A
Authors: Urieli-Shoval Simcha , Shubinsky George , Linke Reinhold P. , Fridkin Mati , Tabi Israel , Matzner Yaacov
Published: July 2002

Serum amyloid A (SAA) is an acute phase reactant, and its level in the blood is elevated to 1000-fold in response of the body to trauma, infection, inflammation, and neoplasia. SAA was reported to inhibit platelet aggregation and to induce adhesion of leukocytes. This study looked at adhesion of human platelets to SAA. Immobilized SAA supported the adhesion of human washed platelets; level of adhesion to SAA was comparable to fibronectin and lower than to fibrinogen. Adhesion to SAA was further enhanced by Mn2+ and the physiological agonist, thrombin. Platelet adhesion to SAA was completely abolished by anti-SAA antibody. SAA-induced adhesion was inhibited by antibodies against the integrin receptor αIIbβ3, by the peptide GRGDSP and by SAA-derived peptide containing YIGSR-like and RGD-like adhesion motifs (amino acids 29 to 42). Adhesion was not inhibited by control immunoglobulin G, by antibody against the integrin receptor αVβ3, by the peptide GRGESP, and by SAA-derived peptide that includes incomplete RGD motif. SAA-derived peptide 29 to 42 also inhibited platelet adhesion to fibronectin. Transfected human melanoma cells expressing αIIbβ3 adhered to SAA, whereas transfected cells expressing αVβ3 did not. By using flow cytometry, the αIIbβ3 cells displayed significantly higher levels of binding of soluble SAA than the αVβ3 cells. These data indicate that human platelets specifically adhere to SAA in an RGD- and αIIbβ3-dependent manner. Thus, SAA may play a role in modulating platelet adhesion at vascular injury sites by sharing platelet receptors with other platelet-adhesive proteins.
Rapid establishment of dendritic cell chimerism in allogeneic hematopoietic cell transplant recipients
Authors: Auffermann-Gretzinger Susanne , Lossos Izidore S. , Vayntrub Tamara A. , Leong Wendy , Grumet F. Carl , Blume Karl G. , Stockerl-Goldstein Keith E. , Levy Ronald , Shizuru Judith A.
Published: July 2002

Regeneration of hematopoiesis after allogeneic hematopoietic cell transplantation (HCT) involves conversion of the recipient's immune system to donor type. It is likely that distinct cell lineages in the recipient reconstitute at different rates. Dendritic cells (DCs) are a subset of hematopoietic cells that function as a critical component of antigen-specific immune responses because they modulate T-cell activation, as well as induction of tolerance. Mature DCs are transferred with hematopoietic grafts and subsequently arise de novo. Little information exists about engraftment kinetics and turnover of this cell population in patients after allogeneic HCT. This study examined the kinetics of DC chimerism in patients who underwent matched sibling allogeneic HCT. T-cell, B-cell, and myelocytic and monocytic chimerism were also studied. Peripheral blood cells were analyzed at defined intervals after transplantation from 19 patients with various hematologic malignancies after treatment with myeloablative or nonmyeloablative preparatory regimens. Cell subsets were isolated before analysis of chimerism. Despite the heterogeneity of the patient population and preparatory regimens, all showed rapid and consistent development of DC chimerism. By day +14 after transplantation approximately 80% of DCs were of donor origin with steady increase to more than 95% by day +56. Earlier time points were examined in a subgroup of patients who had undergone nonmyeloablative conditioning and transplantation. These data suggest that a major proportion of blood DCs early after transplantation is donor-derived and that donor chimerism develops rapidly. This information has potential implications for manipulation of immune responses after allogeneic HCT.
Chlamydia pneumoniae and the lung
Authors: Hammerschlag MR
Published: July 2002

Chlamydia pneumoniae is a frequently occurring respiratory pathogen affecting all age groups. It may cause 5-20% of community-acquired pneumonias in adults and children. The organism has also been implicated as an infectious trigger for asthma. Furthermore, new studies suggest that it may play a role in the pathogenesis of several chronic diseases including atherosclerosis. However, despite the growing significance of C. pneumoniae as a pathogen, progress is hampered by the lack of standardized diagnostic methods including serology and polymerase chain reaction. This makes it practically impossible for the practitioner to make a specific microbiological diagnosis. The lack of standardized methods has also had an adverse effect on treatment trials. The dependence on serology for diagnosis in treatment studies has generated some questionable results. Unless cultures are performed, microbiological efficacy cannot be assessed and it may never be possible to survey for or document the emergence of resistance.