bluuebunny/crossref_metadata_2025 huggingface dataset:
Light field mapping
Authors: Chen Wei-Chao , Bouguet Jean-Yves , Chu Michael H. , Grzeszczuk Radek
Published: October 2002

A light field parameterized on the surface offers a natural and intuitive description of the view-dependent appearance of scenes with complex reflectance properties. To enable the use of surface light fields in real-time rendering we develop a compact representation suitable for an accelerated graphics pipeline. We propose to approximate the light field data by partitioning it over elementary surface primitives and factorizing each part into a small set of lower-dimensional functions. We show that our representation can be further compressed using standard image compression techniques leading to extremely compact data sets that are up to four orders of magnitude smaller than the input data. Finally, we develop an image-based rendering method, light field mapping, that can visualize surface light fields directly from this compact representation at interactive frame rates on a personal computer. We also implement a new method of approximating the light field data that produces positive only factors allowing for faster rendering using simpler graphics hardware than earlier methods. We demonstrate the results for a variety of non-trivial synthetic scenes and physical objects scanned through 3D photography.
The SAGE graphics architecture
Authors: Deering Michael , Naegle David
Published: October 2002

The Scalable, Advanced Graphics Environment (SAGE) is a new high-end, multi-chip rendering architecture. Each single SAGE board can render in excess of 80 million fully lit, textured, anti-aliased triangles per second. SAGE brings high quality antialiasing filters to video rate hardware for the first time. To achieve this, the concept of a frame buffer is replaced by a fully double-buffered sample buffer of between 1 and 16 non-uniformly placed samples per final output pixel. The video output raster of samples is subject to convolution by a 5x5 programmable reconstruction and bandpass filter that replaces the traditional
RAMDAC
. The reconstruction filter processes up to 400 samples per output pixel, and supports any radially symmetric filter, including those with negative lobes (full Mitchell-Netravali filter). Each SAGE board comprises four parallel rendering sub-units, and supports up to two video output channels. Multiple SAGE systems can be tiled together to support even higher fill rates, resolutions, and performance.
Animation and rendering of complex water surfaces
Authors: Enright Douglas , Marschner Stephen , Fedkiw Ronald
Published: October 2002

We present a new method for the animation and rendering of
photo-realistic
water effects. Our method is designed to produce visually plausible three dimensional effects, for example the pouring of water into a glass (see figure 1) and the breaking of an ocean wave, in a manner which can be used in a computer animation environment. In order to better obtain photorealism in the behavior of the simulated water surface, we introduce a new "thickened" front tracking technique to accurately represent the water surface and a new velocity extrapolation method to move the surface in a smooth, water-like manner. The velocity extrapolation method allows us to provide a degree of control to the surface motion, e.g. to generate a windblown look or to force the water to settle quickly. To ensure that the photorealism of the simulation carries over to the final images, we have integrated our method with an advanced physically based rendering system.
Efficient scheduling of conditional behaviors for high-level synthesis
Authors: Kountouris Apostolos A. , Wolinski Christophe
Published: October 2002

As hardware designs get increasingly complex and time-to-market constraints get tighter there is strong motivation for high-level synthesis (HLS). HLS must efficiently handle both dataflow-dominated and controlflow-dominated designs as well as designs of a mixed nature. In the past efficient tools for the former type have been developed but so far HLS of conditional behaviors lags behind. To bridge this gap an efficient scheduling heuristic for conditional behaviors is presented. Our heuristic and the techniques it utilizes are based on a unifying design representation appropriate for both types of behavioral descriptions, enabling the proposed heuristic to exploit under the same framework several well-established techniques (chaining, multicycling) as well as conditional resource sharing and speculative execution which are essential in efficiently scheduling conditional behaviors. Preliminary experiments confirm the effectiveness of our approach and prompted the development of the CODESIS HLS tool for further experimentation.
Enduring practices for managing IT professionals
Authors: Agarwal Ritu , Ferratt Thomas W.
Published: October 2002

Assessing existing business practices to determine staff recruitment and retention capabilities.
GLR parsing with multiple grammars for natural language queries
Authors: Meng Helen , Luk Po-Chui , Xu Kui , Weng Fuliang
Published: October 2002

This article presents an approach for parsing natural language queries that integrates multiple subparsers and subgrammars, in contrast to the traditional single grammar and parser approach. In using
LR(k)
parsers for natural language processing, we are faced with the problem of rapid growth in parsing table sizes as the number of grammar rules increases. We propose to partition the grammar into multiple subgrammars, each having its own parsing table and parser. Grammar partitioning helps reduce the overall parsing table size when compared to using a single grammar. We used the GLR parser with an LR(1) parsing table in our framework because GLR parsers can handle ambiguity in natural language. A parser composition technique then combines the parsers' outputs to produce an overall parse that is the same as the output parse of single parser. Two different strategies were used for parser composition: (i) parser composition by cascading; and (ii) parser composition with predictive pruning.Our experiments were conducted with natural language queries from the ATIS (Air Travel Information Service) domain. We have manually translated the ATIS-3 corpora into Chinese, and consequently we could experiment with grammar partitioning on parallel linguistic corpora. For English, the unpartitioned ATIS grammar has 72,869 states in its parsing table, while the partitioned English grammar has 3,350 states in total. For Chinese, grammar partitioning reduced the overall parsing table size from 29,734 states to 3,894 states. Both results show that
grammar partitioning
greatly economizes on the overall parsing table size. Language understanding performances were also examined. Parser composition imparts a robust parsing capability in our framework, and hence obtains a higher understanding performance when compared to using a single GLR parser.
Enterprise application integration and complex adaptive systems
Authors: Sutherland Jeff , van den Heuvel Willem-Jan
Published: October 2002

Could system integration and cooperation be improved with agentified enterprise components?
Row replacement algorithms for screen editors
Authors: Meyers Eugene W. , Miller Webb
Published: October 2002

Interactive screen editors repeatedly determine terminal command sequences to update a screen row. Computing an optimal command sequence differs from the traditional sequence comparison problem in that there is a cost for moving the cursor over unedited characters and the cost of an
n
-character command is not always the cost of
n
one-character commands. For example, on an ANSI-standard terminal, it takes nine bytes to insert one character, ten to insert two, eleven to insert three, and so on. This paper presents an
O
(
MN
) dynamic programming algorithm for row replacement where an
n
-character command costs α
n
+ β for constants α and β.
M
is the length of the original row and
N
is the length of its replacement. Also given is an
O
(
Cost
× (
M
+
N
)) “greedy” algorithm for optimal row replacement. Here
Cost
is the optimal cost (in bytes) of the replacement, so the algorithm is fast when the require
d update is small. Though the algorithm is rather complicated, it is fast enough to be useful in practice.
Efficient implementation of the first-fit strategy for dynamic storage allocation
Authors: Brent R. P.
Published: October 2002

We describe an algorithm that efficiently implements the first-fit strategy for dynamic storage allocation. The algorithm imposes a storage overhead of only one word per allocated block (plus a few percent of the total space used for dynamic storage), and the time required to allocate or free a block is
O
(log
W
), where
W
is the maximum number of words allocated dynamically. The algorithm is faster than many commonly used algorithms, especially when many small blocks are allocated, and has good worst-case behavior. It is relatively easy to implement and could be used internally by an operating system or to provide run-time support for high-level languages such as Pascal and Ada. A Pascal implementation is given in the Appendix.
A correctness proof for combinator reduction with cycles
Authors: Farmer William M. , Ramsdell John D. , Watro Ronald J.
Published: October 2002

Turner popularized a technique of Wadsworth in which a cyclic graph rewriting rule is used to implement reduction of the fixed point combinator
Y
. We examine the theoretical foundation of this approach. Previous work has concentrated on proving that graph methods are, in a certain sense, sound and complete implementations of term methods. This work is inapplicable to the cyclic
Y
rule, which is unsound in this sense since graph normal forms can exist without corresponding term normal forms. We define and prove the correctness of combinator head reduction using the cyclic
Y
rule; the correctness of normal reduction is an immediate consequence. Our proof avoids the use of infinite trees to explain cyclic graphs. Instead, we show how to consider reduction with cycles as an optimization of reduction without cycles.
Efficient evaluation of circular attribute grammars
Authors: Jones Larry G.
Published: October 2002

We present efficient algorithms for exhaustive and incremental evaluation of circular attributes under any conditions that guarantee finite convergence. The algorithms are derived from those for noncircular attribute grammars by partitioning the underlying attribute dependency graph into its strongly connected components and by ordering the evaluations to follow a topological sort of the resulting directed acyclic graph. The algorithms are efficient in the sense that their worst-case running time is proportional to the cost of computing the fixed points of only those strongly connected components containing affected attributes or attributes directly dependent on affected attributes. When the attribute grammar is noncircular or the specific dependency graph under consideration is acyclic, both algorithms reduce to the standard optimal algorithms for noncircular attribute evaluation.
Remote evaluation
Authors: Stamos James W. , Gifford David K.
Published: October 2002

A new technique for computer-to-computer communication is presented that can increase the performance of distributed systems. This technique, called remote evaluation, lets one computer send another computer a request in the form of a program. A computer that receives such a request executes the program in the request and returns the results to the sending computer. Remote evaluation provides a new degree of flexibility in the design of distributed systems. In present distributed systems that use remote procedure calls, server computers are designed to offer a fixed set of services. In a system that uses remote evaluation, server computers are more properly viewed as programmable processors. One consequence of this flexibility is that remote evaluation can reduce the amount of communication that is required to accomplish a given task. In this paper we discuss the semantics of remote evaluation and its effect on distributed system design. We also summarize our experience with a prototype implementation.
A comparative evaluation of object definition techniques for large prototype systems
Authors: Wileden Jack C. , Clarke Lori A. , Wolf Alexander L.
Published: October 2002

Although prototyping has long been touted as a potentially valuable software engineering activity, it has never achieved widespread use by developers of large-scale, production software. This is probably due in part to an incompatibility between the languages and tools traditionally available for prototyping (e.g., LISP or Smalltalk) and the needs of large-scale-software developers, who must construct and experiment with
large
prototypes. The recent surge of interest in applying prototyping to the development of large-scale, production software will necessitate improved prototyping languages and tools appropriate for constructing and experimenting with large, complex prototype systems. We explore techniques aimed at one central aspect of prototyping that we feel is especially significant for large prototypes, namely that aspect concerned with the definition of data objects. We characterize and compare various techniques that might be useful in defining data objects in large prototype
systems, after first discussing some distinguishing characteristics of large prototype systems and identifying some requirements that they imply. To make the discussion more concrete, we describe our implementations of three techniques that represent different possibilities within the range of object definition techniques for large prototype systems.
Gene Co-Option in Physiological and Morphological Evolution
Authors: True John R. , Carroll Sean B.
Published: October 2002

▪ Abstract  Co-option occurs when natural selection finds new uses for existing traits, including genes, organs, and other body structures. Genes can be co-opted to generate developmental and physiological novelties by changing their patterns of regulation, by changing the functions of the proteins they encode, or both. This often involves gene duplication followed by specialization of the resulting paralogous genes into particular functions. A major role for gene co-option in the evolution of development has long been assumed, and many recent comparative developmental and genomic studies have lent support to this idea. Although there is relatively less known about the molecular basis of co-option events involving developmental pathways, much can be drawn from well-studied examples of the co-option of structural proteins. Here, we summarize several case studies of both structural gene and developmental genetic circuit co-option and discuss how co-option may underlie major episodes of adaptive change in multicellular organisms. We also examine the phenomenon of intraspecific variability in gene expression patterns, which we propose to be one form of material for the co-option process. We integrate this information with recent models of gene family evolution to provide a framework for understanding the origin of co-optive evolution and the mechanisms by which natural selection promotes evolutionary novelty by inventing new uses for the genetic toolkit.
Molecular Mechanisms of Epithelial Morphogenesis
Authors: Schöck Frieder , Perrimon Norbert
Published: October 2002

▪ Abstract  Epithelial morphogenesis comprises the various processes by which epithelia contribute to organ formation and body shape. These complex and diverse events play a central role in animal development and regeneration. Recently, the characterization of some of the molecular mechanisms involved in epithelial morphogenesis has provided an abundance of new information on the role and regulation of the cytoskeleton, cell-cell adhesion, and cell-matrix adhesion in these processes. In this review, we discuss our current understanding of the molecular mechanisms driving cell shape changes, cell intercalation, fusion of epithelia, ingression, egression, and cell migration. Our discussion is mostly focused on results from Drosophila and mammalian tissue culture but also draws on the insights gained from other organisms.
Golgi Architecture and Inheritance
Authors: Shorter James , Warren Graham
Published: October 2002

▪ Abstract  Golgi inheritance proceeds via sequential biogenesis and partitioning phases. Although little is known about Golgi growth and replication (biogenesis), ultrastructural and fluorescence analyses have provided a detailed, though still controversial, perspective of Golgi partitioning during mitosis in mammalian cells. Partitioning requires the fragmentation of the juxtanuclear ribbon of interconnected Golgi stacks into a multitude of tubulovesicular clusters. This process is choreographed by a cohort of mitotic kinases and an inhibition of heterotypic and homotypic Golgi membrane-fusion events. Our model posits that accurate partitioning occurs early in mitosis by the equilibration of Golgi components on either side of the metaphase plate. Disseminated Golgi components then coalesce to regenerate Golgi stacks during telophase. Semi-intact cell and cell-free assays have accurately recreated these processes and allowed their molecular dissection. This review attempts to integrate recent findings to depict a more coherent, synthetic molecular picture of mitotic Golgi fragmentation and reassembly. Of particular importance is the emerging concept of a highly regulated and dynamic Golgi structural matrix or template that interfaces with cargo receptors, Golgi enzymes, Rab-GTPases, and SNAREs to tightly couple biosynthetic transport to Golgi architecture. This structural framework may be instructive for Golgi biogenesis and may encode sufficient information to ensure accurate Golgi inheritance, thereby helping to resolve some of the current discrepancies between different workers.
Sympathetic Nerve Activity in End-Stage Renal Disease
Authors: Hausberg Martin , Kosch Markus , Harmelink Patrick , Barenbrock Michael , Hohage Helge , Kisters Klaus , Dietl Karl Heinz , Rahn Karl Heinz
Published: October 2002

Background—

Uremia is proposed to increase sympathetic nerve activity (SNA) in hemodialysis patients. The aims of the present study were to determine whether reversal of uremia by successful kidney transplantation (RTX) eliminates the increased SNA and whether signals arising in the diseased kidneys contribute to the increased SNA in renal failure.

Methods and Results—

We compared muscle sympathetic nerve activity (MSNA) in 13 hemodialysis patients wait-listed for RTX and in renal transplantation patients with excellent graft function treated with cyclosporine (RTX-CSA, n=13), tacrolimus (RTX-FK, n=13), or without calcineurin inhibitors (RTX-Ø, n=6), as well as in healthy volunteers (CON, n=15). In addition to the above patients with present diseased native kidneys, we studied 16 RTX patients who had undergone bilateral nephrectomy (RTX-NE). Data are mean±SEM. MSNA was significantly elevated in hemodialysis patients (43±4 bursts/min), RTX-CSA (44±5 bursts/min), RTX-FK (34±3 bursts/min), and RTX-Ø (44±5 bursts/min) as compared with CON (21±3 bursts/min), despite excellent graft function after RTX. RTX-NE had significantly reduced MSNA (20±3 bursts/min) when compared with RTX patients. MSNA did not change significantly with RTX in 4 hemodialysis patients studied before and after RTX (44±6 versus 43±5 bursts/min,
P
=NS). In contrast, nephrectomy resulted in reduced MSNA in all 6 RTX patients studied before and after removal of the second native kidney.

Conclusions—

Despite correction of uremia, increased SNA is observed in renal transplant recipients with diseased native kidneys at a level not significantly different from chronic hemodialysis patients. The increased SNA seems to be mediated by signals arising in the native kidneys that are independent of circulating uremia related toxins.
4Q279, 4QFour Lots, UNE INTERPRÉTATION DU PSAUME 135 APPARTENANT À 4Q421, 4QWays of Righteousness
Authors: Hamidovic David
Published: October 2002

La publication officielle de cinq petits fragments, référencés 4Q279 dans le catalogue des manuscrits de Qumrân, a suscité peu d'intérêt dans le microcosme des études qumrâniennes, puisque aucune étude spécifique n'est parue à ce jour. Il est vrai que les manuscrits ne sont accessibles que depuis peu. Pourtant, les hypothèses émises par les éditeurs officiels ne devraient pas être sans retentissement, elles méritent d'être précisées, voire corrigées.
Influence of Preparation Conditions of Mixed-valence Con+/ZSM-5 Zeolites on Their Adsorption and Catalytic Properties in CO Oxidation
Authors: Oleksenko Ludmila P. , Yatsimirsky Vitaly K. , Lutsenko Larisa V.
Published: October 2002

The adsorption properties, thermal stability and catalytic activity in CO oxidation of Co2+, Co3+-containing ZSM-5 zeolite systems with different metal loadings were studied. Treatment in H2 caused an increase in the activity of Co2+/ZSM-5 and Co2+–Co3+/ZSM-5 systems, but the activity of the Co3+/ZSM-5 system remained unchanged, demonstrating the very low reducibility of the [Co(NH3)6]3+ ion when embedded in the zeolite framework. The catalytic activity changed in the order: Co3+/ZSM-5 < Co2+–Co3+/ZSM-5 < Co2+/ZSM-5. A correlation was established between the temperature necessary for the total decomposition of the cobalt salts introduced into the zeolite, the acidity, the coordination state of the Co ions and the catalytic activity of the cobalt-containing zeolites.
Self-assembly of Fibres in Alkylcarboxylate—Sodium Silicate Systems
Authors: Kovalenko A.S. , Yaroshenko N.A. , Strelko V.V. , Ilyin V.G.
Published: October 2002

Fibres of macroscopic size (up to 5 cm in length) formed spontaneously in initially homogeneous systems containing alkali metal salts of saturated n-alkylcarboxylic acids and sodium silicate. After drying, these fibres resembled wool or down, with some being in the form of dense strands which laminated into single fibres with time. The minimal thickness of these single fibres was ca. 0.5 mm and, since a dense parallel cluster contained ca. 34 000 micellar strands, the thickness of each fibre plus associated silicate surface layer amounted to ca. 27 Å. It was suggested that the key feature of the self-assembly mechanism is the weak interaction between a surfactant molecule and a silicate leading to the continuous formation of microscopic sized fibres.
Characterization of a Compliant-Backplate Helmholtz Resonator for An Electromechanical Acoustic Liner
Authors: Horowitz S.B. , Nishida T. , Cattafesta L.N. , Sheplak M.
Published: October 2002

Passive acoustic liners are currently used to reduce the noise radiated from aircraft engine nacelles. This study is the first phase in the development of an actively-tuned electromechanical acoustic liner that potentially offers improved noise suppression over conventional multi-layer liners. The underlying technical concept is based on the idea that the fundamental frequency of a Helmholtz resonator may be adjusted by adding degrees of freedom (DOF) via substitution of a rigid wall with a piezoelectric composite diaphragm coupled to a passive electrical shunt network. In this paper, a Helmholtz resonator containing a compliant aluminum diaphragm is investigated to provide a fundamental understanding of this two DOF system, before adding complexity via the piezoelectric composite material. Using lumped elements, an equivalent circuit model is derived, from which the transfer function and acoustic impedance are obtained. Additionally, a mass ratio is introduced that quantifies the amount of coupling between the elements of the system. The theory is then compared to experiment in a normal-incidence impedance tube. The experimental results confirm the additional DOF and overall acoustic behavior but also suggest the need for a more comprehensive analytical model to accurately predict the acoustic impedance. Nevertheless, the experiments demonstrate the potential benefits of this approach for the reduction of aircraft engine noise.
Cladonia krogiana, a new xanthone-containing species from Norway
Authors: Løfall Bjorn Petter , Timdal Einar
Published: October 2002

The new lichen species Cladonia krogiana is described from eight localities in SE Norway. It resembles C. polycarpoides morphologically, but differs in containing barbaric acid and chlorovinetorin.
Bacidia brandii, a new lichen species from the Netherlands, Belgium, France and Lithuania
Authors: Coppins B. J. , van den Boom P. P. G.
Published: October 2002

A new lichen species from the genus Bacidia s. lat., B. brandii, is described from the Netherlands, Belgium, France and Lithuania. It has been found terricolous, on brick, on lignum and on plant debris. The new species belongs to a group sometimes treated in the genus Bacidina Vězda, and shows particular affinities to Bacidia amoldiana, B. chloroticula and B. saxenii.
Cladonia singhii and other new reports of Cladonia from the Eastern Himalayan Region of India
Authors: Ahti Teuvo , Dixit P. K. , Singh K. P. , Sinha G. P.
Published: October 2002

A new species, Cladonia singhii Ahti & Dixit (type from the state of Arunachal Pradesh), is described. A further seven Cladonia species, C. corniculata, C. kanewskii, C. laii, C. luteoalba, C. mauritiana, C. mongolica and C. rei, are reported as new to the recent checklist of lichens of the Indian subcontinent. The presence of C. cartilaginea in India is confirmed.
Pollen- and Diatom-Inferred Climatic and Hydrological Changes in Sumxi Co Basin (Western Tibet) since 13,000 yr B.P.
Authors: Van Campo Elise , Gasse Francoise
Published: October 2002

Although the Tibetan Plateau greatly influences the atmospheric circulation of the Nortbern Hemisphere, few continuous paleoclimatic records are available from the plateau. A 13,000-yr pollen and diatom record from the Sumxi-Longmu Co basin in western Tibet gives information on major changes both in regional vegetation and in local hydrology. After the basin first filled ca. 13,000 yr B.P., a dry spell occurred about 10,500 yr B.P. within the interval spanned by the European Younger Dryas chronozone. A major environmental change occurred suddenly at ≈10,000 yr B.P., with the establishment of wet conditions, and was followed by a long-term trend toward maximum aridity, which lasted approximately 6000 yr. Short-term oscillations are superimposed on this general climatic change with a major reversal event about 8000 yr B.P. and a second wet pulse leading to a maximum lake volume ca. 7500-6000 yr B.P. Maximum aridity occurred 4300 yr B.P. The major environmental fluctuations recorded at Sumxi-Longmu Co appear in phase with climatic changes recognized in north tropical Africa, suggesting that the 8000 to 7000-yr-B.P. event was caused by an abrupt disequilibrium in the climatic system, as was the Younger Dryas and possibly the 4300-yr-B.P. event.
New Isotopic and Sedimentological Measurements of the Thabaseek Deposits (South Africa) and the Dating of the Taung Hominid
Authors: Tobias Phillip V. , Vogel John C. , Oschadleus H. Dieter , Partridge Timothy C. , McKee Jeffrey K.
Published: October 2002

Earlier attempts to date the Taung hominid type specimen of Australopithecus africanus Dart yielded conflicting results. Recent faunal studies pointed to an age of 2.3 myr. Radioisotopic results suggested 1.0 myr. New uranium studies reveal that the Thabaseek (the oldest Taung tufa) was not a closed system and that younger uranium entered the tufa after initial deposition, producing an apparent isotopic age younger than the age of deposition. The Thabaseek isotopic dates provide only a terminus ad quem and this technique is therefore not applicable to the older Taung tufas. Delson's dating (2.3 myr) of cercopithecoids from Hrdlicka's pinnacle ca. 50 m from the hominid site provides the best available approximation to the age of the hominid. In our new Taung excavation, stratigraphic analysis indicates that the hominid may somewhat predate most identified fauna. Sedimentologically the hominid matrix proves to be of fluvial deposition, and hence closely resembles one Hrdlicka deposit, both samples differing appreciably from all other Taung samples which bespeak eolian deposition. Thus, the conditions under which the hominid-bearing stratum was deposited were virtually identical to those pertaining to one of the Hrdlicka deposits. The newest results show that Taung was not the youngest South African australopithecine site and eliminate the discrepancy between the relative ages of the Taung A. africanus africanus and the Sterkfontein A. africanus transvaalensis.
Late Quaternary (Stage 2 and 3) Meltwater and Heinrich Events, Northwest Labrador Sea
Authors: Andrews John T. , Erlenkeuser Helmut , Tedesco Katherine , Aksu Ali E. , Jull A.J.Timothy
Published: October 2002

Two major meltwater events are documented in cores from the NW Labrador Sea. One occurred ca. 20,00014C yr B.P. in association with deposition of a major detrital carbonate unit. Both prior to and after this event, δ18O values of near-surface planktonic foraminifera were 4.5%, indicating fully enriched glacial values. A younger event (ca. 14,00014C yr B.P.) is characterized by a dramatic change in δ18O from 4.5 to 2.0% and coincided with the retreat of ice from the outer SE Baffin Shelf, possibly into Hudson Strait. These meltwater events coincide with Heinrich (H) layers 1 and 2 from North Atlantic sediments. The 14,00014C yr B.P. meltwater event indicates that the eastern margin of the Laurentide Ice Sheet also underwent rapid retreat at approximately the same time as other ice sheet margins around the NE North Atlantic. A third major detrital carbonate event at the base of HU87-033-009, possibly correlative with Heinrich layer 3, occurred ca. 33,960 ± 67514C yr B.P.; however, this is older than the accepted date for H-3 of 27,00014C yr B.P. and may be H-4.
Aminostratigraphic Correlation and Geochronology of Two Quaternary Loess Localities, Central Mississippi Valley
Authors: Mirecki June E. , Miller Barry B.
Published: October 2002

Amino acid epimeric (aIle/Ile) values from terrestrial molluscs are used to define and correlate three aminozones in loess sequences exposed across the central Mississippi Valley, in Arkansas and Tennessee. Three superposed aminozones are defined at Wittsburg quarry, Arkansas, primarily using aIle/Ile values from total hydrolysates of the gastropod genusHendersonia:Peoria Loess (aIle/Ile = 0.07 ± 0.01), Roxana Silt (0.14 ± 0.02), and a third loess (0.28 ± 0.06). Loess units at Wittsburg quarry can be correlated on lithologic characteristics eastward across the Mississippi Valley to the Old River section, near Memphis, Tennessee; however, only one loess unit is fossil-bearing (Peoria Loess, aIle/Ile = 0.05) at that section. Radiocarbon analyses of charcoal from the upper Roxana Silt (ca. 26,000 to 29,000 yr old) and mollusc shell carbonate from the basal Roxana Silt (ca. 39,000 yr old) are used to calibrate amino acid epimeric data for the central Mississippi Valley. These data, applied to the apparent parabolic kinetic model of R. M. Mitterer and N. Kriausakul (1989,Quaternary Science Reviews8, 353-357), suggest an Illinoian (>120,000 yr) age for the third loess in the central Mississippi Valley that is correlative with part of the Loveland Loess in Illinois and Iowa.
Organic Remains in Finnish Subglacial Sediments
Authors: Punkari Mikko , Forsström Lars
Published: October 2002

Many sites in Fennoscandia contain pre-Late Weichselian beds of organic matter, located mostly in the flanks of eskers. It is a matter of debate whether these fragmentary beds were deposited in situ, or whether they were deposited elsewhere and then picked up and moved by glacial ice. The till-mantled esker of Harrinkangas includes a shallow depression filled with sand and silt containing, for example, several tightly packed laminar sheets of brown moss (Bryales) remains. It is argued that these thin peat sheets were transported at the base of the ice sheet, or englacially, and were deposited together with the silt and sand on the side of a subglacial meltwater tunnel. Subglacial meltout till subsequently covered the flanks of the esker near the receding ice margin. Information about the depositional and climatic environments was obtained from biostratigraphic analysis of the organic matter. Pollen spectra for the peat represent an open birch forest close to the tundra zone. A thin diamicton beneath the peat contains charred pine wood, recording the former presence of pine forests in western Finland. The unhumified, extremely well-preserved peat evidently originated during the final phase of an ice-free period, most probably the end of the Eemian Interglaciation. It was redeposited in the esker by the last ice sheet. Reconstructions of the Pleistocene chronology and stratigraphy of central Fennoscandia that rely on such redeposited organic matter should be viewed with caution.
Optical Dating of Tsunami-Laid Sands
Authors: Huntley David J. , Clague John J.
Published: October 2002

The ages of some tsunami deposits can be determined by optical dating, a key requirement being that the deposits are derived from sediment that was reworked and exposed to daylight by tidal currents, waves, wind, or bioturbation during the last years before the tsunami. Measurements have been made using 1.4 eV (infrared) excitation of K-feldspar grains separated from samples of prehistoric tsunami sand sheets and modern analogs of tsunami source sediments at four sites in Washington state and British Columbia. Source sands gave equivalent doses indicative of recent exposure to daylight. Tsunami sand at Cultus Bay, Washington, yielded an optical age of 1285 ± 95 yr (calendric years before A.D. 1995, ±1σ). At 2σ, this age overlaps the range of from 1030 to 1100 yr determined through a combination of high-precision radiocarbon dating and stratigraphic correlation. Tsunami sands at three sites near Tofino and Port Alberni on Vancouver Island, British Columbia, have optical ages of 260 ± 20, 325 ± 25, and 335 ± 45 yr. Historical records and radiocarbon dating show that the sand at each of the three sites is between 150 and 400 yr old. These optical ages support the hypothesis that the Vancouver Island sands were deposited by a tsunami generated by a large earthquake on the Cascadia subduction zone about 300 yr ago.
An Ice Age Refugium for Large Mammals in the Alexander Archipelago, Southeastern Alaska
Authors: Heaton Timothy H. , Talbot Sandra L. , Shields Gerald F.
Published: October 2002

Genetic and paleontological evidence are combining to provide a new and surprising picture of mammalian biogeography in southeastern Alaska. Prior to our study, the brown and black bears of the Alexander Archipelago were considered postglacial immigrants that never had overlapping ranges. Vertebrate fossils from caves on Prince of Wales Island now demonstrate that brown and black bears coexisted there (and even inhabited the same caves) both before and after the last glaciation. Differences in mtDNA sequences suggest that living brown bears of the Alexander Archipelago comprise a distinct clade and are more closely related to polar bears than to their mainland conspecifics. We conclude that brown bears, and perhaps other large mammals, have continuously inhabited the archipelago for at least 40,000 yr and that habitable refugia were therefore available throughout the last glaciation.
Paleoenvironmental Changes during the Last 4000 yr in the Tigray, Northern Ethiopia
Authors: Machado Maria J. , Pérez-González Alfredo , Benito Gerardo
Published: October 2002

In the Tigray region at the northern Ethiopian Highlands, paleoenvironmental reconstruction based on several infilled valley deposit sequences suggests that the past 4000 yr comprised three major wetter periods (ca. 4000–3500 yr B.P., 2500–1500 yr B.P., and 1000–960 yr B.P.), during which soils were formed, and two degradation episodes (ca. 3500–2500 yr B.P. and 1500–1000 yr B.P.), during which there was an increase of sediment yield from the slopes into the valleys. For the past 1000 yr, and in particular since the early 17th century, stratigraphic records together with historic chronicles suggest increasing aridity. Although difficulties arise in distinguishing between natural and human impacts, particularly in a region with a long established agricultural background, stratigraphical and proxy paleoclimatic data have indicated climate as the main controlling factor responsible for the environmental changes in the Tigray.
Climatic Implications of the S5 Paleosol Complex on the Southernmost Chinese Loess Plateau
Authors: Han Jingtai , Fyfe William S. , Longstaffe Fred J.
Published: October 2002

The S5 is the most prominent paleosol unit in the Chinese Loess Plateau, and is distinguished by its great thickness, dark color, and well-developed clay coatings. Previous studies led to the proposal that the S5 developed under much warmer and wetter conditions than at present, implying a “climatic optimum.” However, the S5 is a paleosol complex corresponding in time to a period of weak glacial–interglacial oscillations, as recorded by marine oxygen-isotope stages 15 through 13. To understand the character of this climatic interval, two profiles of the paleosol S5 in the Guanzhong basin were studied, with most of the emphasis being placed on the uppermost and best-developed pedon, S5-I. Grain-size, mineralogical, and chemical data indicate that the major pedogenic processes experienced by the S5-I included complete decalcification and mechanical translocation of fine particles. Chemical alteration of silicate minerals has been weak. Stable carbon-isotope analyses of organic matter showed that C4 plant remains are abundant throughout the profiles. These results suggest that grasslands dominated the paleovegetation during S5-I development. The prominent development of the S5 paleosol complex may reflect a prolonged period of pedogenesis. In contrast to previous reports, paleoclimatic conditions perhaps even drier than at present are implied by the data for the S5 profiles. The relative strength of the glacial–interglacial oscillation in this region (related to the East Asian monsoon) was similar to that indicated for global climate during S5 time.
Reinterpretation of the Burmester Core, Bonneville Basin, Utah
Authors: Oviatt Charles G. , Thompson Robert S. , Kaufman Darrell S. , Bright Jordon , Forester Richard M.
Published: October 2002

Initial interpretation of the sediments from the Burmester core (Eardleyet al.(1973).Geological Society of America Bulletin84, 211–216) indicated that 17 deep-lake cycles, separated by shallow-lake and soil-forming intervals, occurred in the Bonneville basin during the Brunhes Chron (the last 780 × 103yr). Our re-examination of the core, along with new sedimentological, geochronological, and paleontological data, indicate that only four deep-lake cycles occurred during this period, apparently correlative with marine oxygen-isotope stages 2, 6, 12, and 16. This interpretation suggests that large lakes formed in the Bonneville basin only during the most extensive of the Northern Hemisphere glaciations.
Heterogeneous exchange behavior of Samia cynthia ricini silk fibroin during helix–coil transition studied with 13C NMR
Authors: Nakazawa Yasumoto , Asakura Tetsuo
Published: October 2002

The structure and structural transition of the glycine residue adjacent to the N‐terminal alanine residue of the poly(L‐alanine), (Ala)12–13, region in Samia cynthia ricini silk fibroin was studied using 13C nuclear magnetic resonance (NMR). Most of the glycine carbonyl peaks in the 13C solution NMR spectrum of [1‐13C]glycine‐silk fibroin could be assigned to the primary structure from the comparison of the 13C chemical shifts of seven glycine‐containing tripeptides. The slow exchange between helix and coil forms in the NMR time scale was observed with increasing temperature exclusively for the underlined glycine residue in the Gly‐‐(Ala)12–13 sequence during fast helix–coil transition of the (Ala)12–13 region.
The vasodilator‐stimulated phosphoprotein promotes actin polymerisation through direct binding to monomeric actin
Authors: Walders-Harbeck Birgit , Khaitlina Sofia Y , Hinssen Horst , Jockusch Brigitte M , Illenberger Susanne
Published: October 2002

The vasodilator‐stimulated phosphoprotein (VASP) functions as a cellular regulator of actin dynamics. VASP may initialise actin polymerisation, suggesting a direct interaction with monomeric actin. The present study demonstrates that VASP directly binds to actin monomers and that complex formation depends on a conserved four amino acid motif in the EVH2 domain. Point mutations within this motif drastically weaken VASP/G‐actin interactions, thereby abolishing any actin‐nucleating activity of VASP. Additionally, actin nucleation was found to depend on VASP oligomerisation since VASP monomers fail to induce the formation of actin filaments. Phosphorylation negatively affects VASP/G‐actin interactions preventing VASP‐induced actin filament formation.
Eukaryotic initiation factor 4GI is a poor substrate for HIV‐1 proteinase
Authors: Schlick Petra , Skern Tim
Published: October 2002

Eukaryotic initiation factor (eIF) 4GI is efficiently cleaved during picornaviral replication. eIF4GI processing has also recently been observed during HIV‐1 replication. We have compared the efficiency of eIF4GI proteolysis in rabbit reticulocyte lysates during translation of mRNAs encoding the foot‐and‐mouth disease virus leader proteinase (Lpro) or the HIV‐1 proteinase (HIV‐1pro). Lpro cleaved 50% eIF4GI within 12 min whereas HIV‐1pro required 4 h; the concentrations were 2 pg/μl (0.1 nM) for Lpro and 60 pg/μl (2.66 nM) for HIV‐1pro. HIV‐1pro processing of eIF4GI is therefore not quantitatively analogous to that of Lpro, suggesting that the primary function of eIF4GI cleavage in HIV‐1 replication may not be protein synthesis inhibition.
The Policy-Making and Political Economy of the Abolition of Private Ownership in the Early
1950s: Findings from New Material
Authors: Wai-yip So Bennis
Published: October 2002

The private sector has become an indispensable part of Chinese economic growth since its revival from the early 1980s. This raises the issue of the justifiability of the abolition of private ownership by the socialist transformation from 1953. Many Chinese intellectuals now suggest the CCP put an end to New Democracy too early. With new material released since the 1980s, the author argues that the private sector had sharply declined under New Democracy as the Party tried to boost the development of the private economy in default of a market economy. This article substantiates the view that the implementation of the New Democracy policy during 1949–52 was significantly moulding and re-defining the policy goal towards the private economy.
Population structure and secondary production of Heteromastus filiformis (Polychaeta: Capitellidae) in the Loire estuary, France
Authors: Gillet Patrick , Gorman Eric
Published: October 2002

A survey was carried out from April 1998 to June 2000 to study the structure and the secondary production of the population of Heteromastus filiformis in the Loire estuary. Each month, samples were collected in the intertidal zone of Mindin harbour. The length of the thorax (L12) was correlated with the fresh weight (FW) with the relation FW=1·49848 L12–3·62804 (r=0·92). In 1999, the mean density was 2184 ind m−2 with a minimum of 1104 ind m−2 in December and a maximum of 3328 ind m−2 in March. The mean annual biomass was 15·4 g m−2 with a minimum of 2·6 g m−2 in December and a maximum of 28·2 g m−2 in March. Most of the histograms of size–frequency are unimodal and could be considered a single cohort except in May and November/December 1999. The abundance and biomass of the population of H. filiformis decreased during summer and winter which are mortality periods and increase during spring and autumn which are recruitment periods for the population. The life time for a cohort was from six to nine months depending on the recruitment period and on the inter-annual variations. The secondary production was estimated by the method of Crisp (1971). The annual secondary production in 1999 was P=104·3 g m−2 with B¯=15·4 g m−2 and P:B¯=6·8. The quantity of sediment reworked by H. filiformis is about 116 l m−2 y−1 or 65 kg m−2 y−1 which is approximately a deep-sediment layer of 12 cm transported to the surface annually.
Counselling older adults
Authors: Rainsford Catriona
Published: October 2002

The term counselling is a nebulous one. For the purposes of this paper it refers to a therapeutic approach that places value on the person’s subjective experience and challenges the person to accept responsibility for his or her own life. The relationship that develops between counsellor and client can foster personal growth. The overall aim is to provide an opportunity for the client to work towards living in a way he or she experiences as more satisfying and resourceful. Counselling may be concerned with addressing and resolving specific problems, making decisions, coping with crises, working through conflict or improving relationships with others.
Discrimination of hydrogen-bonded complexes with axial chirality
Authors: Alkorta Ibon , Elguero José
Published: October 2002

The chiral self-discrimination of twelve molecules showing axial chirality has been studied. They included peroxides, hydrazines, carboxylic acids, amides, and allenes. The homo and heterochiral dimers of the selected compounds, that present two hydrogen bonds, have been studied by means of density functional theory (B3LYP/6-31+G**) and ab initio (MP2/6-31+G** and MP2/6-311++G**) methods. The energetic differences found for the complexes of each compound have been rationalized based on their electron density maps and the natural bond orbital analysis. In some cases, intermolecular oxygen–oxygen interactions have been found and interpreted as additional stabilizing contacts.
Universal molecule injector in liquid helium: Pulsed cryogenic doped helium droplet source
Authors: Ghazarian V. , Eloranta J. , Apkarian V. A.
Published: October 2002

Progress toward the construction of a universal molecule injector for doping bulk liquid helium is reported. A pulsed valve that operates at cryogenic temperatures, down to 4 K, is demonstrated within the confinement of a cryostat, operating in the vapor above a steady level of liquid He. The insulated valve can be operated at elevated temperatures with preseeded helium gas in supersonic expansion mode, as demonstrated through laser-induced fluorescence spectra of seeded NO2. At cryogenic operating temperatures, the expansion into vapor helium produces a well-collimated liquid helium droplet beam, which is then used to transfer to the liquid impurities produced by laser ablation from a cryogenic rotating target. The operation can be visualized using copper as the ablation target: the droplet beam is imaged via Rayleigh scattering, while the beam past the plasma is imaged by the fluorescence of the entrained Cu atoms. The beam drags along copper ions and electrons, the recombination of which controls the fluorescence yield downstream.
Effect of “overshooting” in the transitional regimes of the low-current gliding arc discharge
Authors: Kuznetsova I. V. , Kalashnikov N. Y. , Gutsol A. F. , Fridman A. A. , Kennedy L. A.
Published: October 2002

A linear stability analysis of the low-current gliding arc discharge in the transitional regime is performed. It is shown that the gliding arc remains stable during the evolution and gradually transforms into a more nonequilibrium one. The low-current arc discharge can propagate with the effect of “overshooting” at which the gliding arc extinguishes long after its maximum power has been achieved. Analytical and numerical solutions explain the general behavior of the low-current gliding arc and are in a good agreement with our experiment.