bluuebunny/crossref_metadata_2025_split huggingface dataset:
Late Quaternary Biomass Changes from 13C Measurements in a Highland Peatbog from Equatorial Africa (Burundi)
Authors: Aucour Anne-Marie , Hillaire-Marcel Claude , Bonnefille Raymonde 
Published: October 2002

AbstractStable carbon isotope ratios of total organic matter were measured in two cores collected from the Kashiru peatbog in Burundi, Equatorial Africa. The record, which spans at least the last 40,000 yr, documents the C3-C4 biomass balance in the organic sediment. Among the major modern peat formers, most plants are C3 species and are characterized by δ13C values of -25.5 ± 2.3% (vs PDB). The C4 plants, which are characterized by higher δ13C values (-11.3 ± 0.7%) belong to the Gramineae (Miscanthidium sp.) and Cyperaceae families (Cyperus latifolius, C. papyrus, Pycreus nigricans). In the fossil record, δ13C values of total organic matter vary between -28 and -15% in response to the relative fluxes of C3 and C4 plants. Before 30,000 yr B.P., low δ13C values (-23.5 ± 1.1%) match high arboreal pollen contents. From 30,000 to 15,000 yr B.P., higher δ13C values (-17.6 ± 1.1%) correspond to a significant increase in percentages of grass pollen. During this episode, a short and sharp shift toward lighter carbon isotopic compositions at 21,000 yr B.P. is synchronous with higher input of arboreal pollen. From 15,000 to 12,000 yr B.P., the 13C content decreases (δ13C = -22.9 ± 1.4%). This shift, which cannot be explained by an increase in the arboreal vegetation, could be explained by the spreading of C3 Gramineae or C3 Cyperaceae. The interval from 12,000 to 7000 yr B.P. is poorly documented in these cores due to much lower organic matter accumulation. Low δ13C values (δ13C = -25.2 ± 1.3%) are observed from 7000 to 5000 yr B.P., when the pollen data show development of C3 mountain forest. The Late Holocene is characterized by a mixed C3-C4 organic matter accumulation (δ13C = -20.9 ± 1.6%). This study depicts a change in the dominant photosynthetic pathway among the herbaceous components, notably at the glacial-interglacial transition, when C3 plants were favored by increased water supply and/or higher atmospheric CO2 concentration.
Sea-Surface Temperature Estimates for the Tropical Western Pacific during the Last Glaciation and Their Implications for the Pacific Warm Pool
Authors: Thunell Robert , Anderson David , Gellar Debrorah , Miao Qingmin 
Published: October 2002

AbstractTwenty deep-sea sediment cores from the western Pacific between 30°N and 30°S provide evidence of sea-surface temperature (SST) changes throughout the tropics and subtropics. Glacial SSTs were estimated using the modern analog technique (MAT) applied to planktonic foraminifers and planktonic foraminiferal δ18O changes. We used δ18O to identify the last glacial maximum. The MAT method differs from the traditional transfer function approach in that it utilizes a global coretop database, and estimates paleotemperature by finding analogs from the modern coretop samples. In addition, the MAT approach appears to be less susceptible than the transfer function technique to biases introduced by carbonate dissolution. Our results indicate that tropical SSTs differed by less than 2°C from present; away from the tropics (30°N and 30°S) SSTs were at least 3°C cooler. Our results differ from those of previous studies in the western Pacific by using a set of well-preserved, high-sedimentation rate cores from shallow regions. The results of this study clearly indicate that a western Pacific warm pool existed during the last glacial maximum (LGM), providing a heat and moisture source for a Walker Circulation cell similar to that of today. We propose that a steeper lapse rate existed during the last glacial maximum and that this can explain at least part of the discrepancy between marine and terrestrial temperature estimates adjacent to New Guinea for the LGM.
Stability of Holocene Climate Regimes in the Yellowstone Region
Authors: Whitlock Cathy , Bartlein Patrick J. , Van Norman Kelli J. 
Published: October 2002

AbstractA 12,500-yr pollen record from Loon Lake, Wyoming provides information on the climate history of the southwestern margin of Yellowstone National Park. The environmental reconstruction was used to evaluate hypotheses that address spatial variations in the Holocene climate of mountainous regions. Loon Lake lies within the summer-dry/winter-wet climate regime. An increase in xerophytic pollen taxa suggests drier-than-present conditions between ca. 9500 and 5500 14C yr B.P. This response is consistent with the hypothesis that increased summer radiation and the expansion of the east Pacific subtropical high-pressure system in the early Holocene intensified summer drought at locations within the summer-dry/winter-wet regime. This climate history contrasts with that of nearby sites in the summer-wet/winter-dry region, which were under the influence of stronger summer monsoonal circulation in the early Holocene. The Loon Lake record implies that the location of contrasting climate regimes did not change in the Yellowstone region during the Holocene. The amplitude of the regimes, however, was determined by the intensity of circulation features and these varied with temporal changes in the seasonal distribution of solar radiation.
Tsunami Deposits Beneath Tidal Marshes on Northwestern Vancouver Island, British Columbia
Authors: Benson Boyd E. , Grimm Kurt A. , Clague John J. 
Published: October 2002

AbstractTwo sand sheets underlying tidal marshes at Fair Harbour, Neroutsos Inlet, and Koprino Harbour on the northwestern coast of Vancouver Island, British Columbia, were probably deposited by tsunamis. The sand sheets become thinner and finer-grained landward, drape former land surfaces, contain marine microfossils, are locally graded or internally stratified, and can be correlated with earthquakes that generated tsunamis in the region. 137Cs dating and historical accounts indicate that the upper sand sheet was deposited by the tsunami from the great Alaska earthquake in 1964. Radiocarbon ages on plant fossils within and on top of the lower sand sheet show that it was deposited sometime after about A.D. 1660. We attribute the lower sand sheet to a tsunami from the most recent plate-boundary earthquake on the Cascadia subduction zone about 300 yr ago, extending the documented effects of this earthquake north of the Nootka fault zone. The 1964 tsunami deposits differ little in thickness and continuity among the three marshes. In contrast, the lower sand sheet becomes thinner and less continuous to the north, implying a tsunami source south of the study area.
Lake-Level Chronology on the Southern Bolivian Altiplano (18°–23°S) During Late-Glacial Time and the Early Holocene
Authors: Sylvestre Florence , Servant Michel , Servant-Vildary Simone , Causse Christiane , Fournier Marc , Ybert Jean-Pierre 
Published: October 2002

AbstractStratigraphic analyses of outcrops, shorelines, and diatoms from the southern Bolivian Altiplano (Uyuni-Coipasa basin) reveal two major lacustrine phases during the late-glacial period and the early Holocene, based on a chronology established by radiocarbon and U/Th control. A comparison of14C and230Th/234U ages shows that during times of high lake level, radiocarbon ages are valid. However, during low-water periods,14C ages must be corrected for a reservoir effect. The lacustrine Tauca phase started a little before 16,00014C yr B.P., and the lake level reached its maximum between 13,000 and 12,00014C yr B.P. A dry event (Ticaña) occurred after ca. 12,000 and before 950014C yr B.P. A moderate lacustrine oscillation (Coipasa event) occurred between ca. 9500 and 850014C yr B.P., using a reservoir-corrected conventional14C chronology. Comparisons between the lake-level chronology in the Uyuni-Coipasa basin and data from other southern tropical areas of South America suggest that the lacustrine evolution may reflect large-scale climatic changes.
Dating the Lower Paleolithic Open-Air Site of Holon, Israel by Luminescence and ESR Techniques
Authors: Porat Naomi , Zhou Li Ping , Chazan Michael , Noy Tamar , Horwitz Liora Kolska 
Published: October 2002

AbstractThe open-air Acheulian site in Holon, Israel, was dated by the luminescence methods and by electron spin resonance (ESR). Situated in the coastal plain Quaternary Kurkar Group, the Holon site was first excavated in the late 1960s, when typical lower Paleolithic lithics and middle Pleistocene fauna were found. In order to date the site, new test pits were dug adjacent to the earlier excavations and the archaeological bed was exposed in a section comprising a series of paleosols and aeolianites. Alkali feldspars separated from the sediments were dated using the infrared stimulated luminescence and thermoluminescence signals, and quartz was dated using the optically stimulated luminescence signal. The age of the archaeological bed is constrained by two samples to 198,000 ± 22,000–201,000 ± 17,000 yr. The age of the base of the section is 240,000 ± 29,000 yr, and the age of the top is 81,000 ± 8000 yr. Two teeth from the archaeological bed, recovered from the original excavation collection, yielded an average ESR age of 204,000 ± 16,000 yr, calculated using the linear uptake model, which is in a very good agreement with the luminescence ages. These dates place Holon within the range of other late Acheulian and Acheulo-Yabrudian sites in this region such as Tabun E (younger chronology), Yabrud I (archaeological level 18), and Berekhat Ram.
The Climate and Landscape of the Middle Part of the Weichselian Glaciation in Europe: The Stage 3 Project
Authors: van Andel Tjeerd H. 
Published: October 2002

AbstractOxygen isotope stage 3 (OIS 3) was a mild interval between the two cold maxima of the last (Weichselian) glaciation marked by climate changes oscillating on a 100–1000 yr time scale between near-interglacial and peak-glacial conditions. During OIS 3, modern humans entered Europe, and somewhat later their Neanderthal predecessors became extinct. Our understanding of this momentous event depends on an answer to the question, Did the unstable environmental conditions of the time play a significant role in early human history? The Stage 3 Project is an interdisciplinary study with two main goals: (1) to describe with existing data and to simulate the climates and landscapes of typical warm and cold phases between 45,000 and 30,000 yr ago and (2) to compare the results with the spatial and temporal distribution of human beings in this context. This paper introduces the Stage 3 Project and provides background to a set of papers on the climate and landscape aspects of the Project that will appear in Quaternary Research and to studies of their relevance to the Early Upper Paleolithic of Europe to appear in journals yet to be determined.
Deriving Proof Rules from Continuation Semantics
Authors: Audebaud Philippe , Zucca Elena 
Published: October 2002

Abstract.

We claim that a continuation style semantics of a programming language can provide a starting point for constructing its proof system. The basic idea is to see weakest preconditions as a particular instance of continuation style semantics, hence to interpret correctness assertions (e.g. Hoare triples {
p
}
C
{
r
}) as inequalities over continuations. This approach also shows a correspondence between labels in a program and annotations.
Cache Coherency in SCI: Specification and a Sketch of Correctness
Authors: Felty Amy , Stomp Frank 
Published: October 2002

Abstract.
SCI – Scalable Coherent Interface – is an IEEE standard for specifying communication between multiprocessors in a shared memory model. In this paper we model part of SCI by a program written in a UNITY-like programming language. This part of SCI is formally specified in Manna and Pnueli's Linear Time Temporal Logic (LTL). We give a sketch of our proof that the program satisfies its specification. The proof has been carried out within LTL. It uses history variables. Structuring of the proof has been achieved by careful formulation of lemmata and the use of auxiliary predicates as an abstraction mechanism.
Testing Conformance to a Quasi-Non-Deterministic Stream X-Machine
Authors: Hierons R. M. , Harman M. 
Published: October 2002

Abstract.
Stream X-machines have been used in order to specify a range of systems. One of the strengths of this approach is that, under certain well-defined conditions, it is possible to produce a finite test that is guaranteed to determine the correctness of the implementation under test (IUT). Initially only deterministic stream X-machines were considered in the literature. This is largely because the standard test algorithm relies on the stream X-machine being deterministic.

More recently the problem of testing to determine whether the IUT is
equivalent
to a non-deterministic stream X-machine specification has been tackled. Since non-determinism can be important for specifications, this is an extremely useful extension. In many cases, however, we wish to test for a weaker notion of correctness called
conformance
. This paper considers a particular form of non-determinism, within stream X-machines, that will be called quasi-non-determinism. It then investigates the generation of tests that are guaranteed to determine whether the IUT
conforms
to a quasi-non-deterministic stream X-machine specification. The test generation algorithm given is a generalisation of that used for testing from a deterministic stream X-machine.
Generalised Stream X-Machines with Output Delimited Type
Authors: Bălănescu Tudor 
Published: October 2002

Abstract.

Some conditions relating to the automata involved in the W-testing method are discussed. It is also shown how to use the method for
reduced automata
instead of minimal automata. New design test conditions (
weak output distinguishable
,
strong test-complete and output delimited type
) are considered for the
generalised stream X-machines
(stream X-machines with basic functions replaced by relations and having as output strings of symbols rather than single symbols). It is proved that testing methods similar to those already developed for ordinary deterministic stream X-machines may be applied for generalised stream X-machines with output delimited types. A particular case of generalised stream X-machine with output delimited type is the X-machine with
output delimiter
, which produces outputs having a distinct right end character.
Using VDMTools to Model and Validate the Cash Dispenser Example
Authors: Larsen Peter Gorm , Mukherjee Paul , Sunesen Kim 
Published: October 2002

Abstract.
This document gives a short overview of how VDMTools® can be used in different stages of the system/software development process. The application used is a cash dispensing machine, first introduced at the FM'99 Symposium as the basis for a competition amongst tool vendors. The document provides an overview of how we at IFAD envisage that a problem such as this one should be attacked using VDMTools®.
The ‘Cash-Point’ Service: A Verification Case Study Using STeP
Authors: Browne Anca , Finkbeiner Bernd , Manna Zohar , Sipma Henny 
Published: October 2002

Abstract.

STeP, the Stanford Temporal Prover, supports the computer-aided formal verification of concurrent and reactive systems based on temporal specifications [MBB99]. Automated
model checking
is combined with computer-aided
deductive methods
to allow for the verification of a broad class of systems, including parameterised (
N
-component) circuit designs, parameterised (
N
-process) programs, and programs with infinite data domains.
Maximally Concurrent Programs
Authors: Joshi Rajeev , Misra Jayadev 
Published: October 2002

Abstract.

Typically, program design involves constructing a program
P
that
implements
a given specification
S
; that is, the set
${\overline P}$
of executions of
P
is a subset of the set
${\overline S}$
of executions satisfying
S
. In many cases, we seek a program
P
that not only implements
S
, but for which
${\overline P}$
=
${\overline S}$
. Then, every execution satisfying the specification is a possible execution of the program; we then call
P maximal
for the specification
S
. We argue that maximality is an important criterion in the context of designing concurrent programs because it disallows implementations that do not exhibit enough concurrency. In addition, a maximal solution can serve as a basis for deriving a variety of implementations, each appropriate for execution on a specific computing platform. This paper also describes a method for proving the maximality of a program with respect to a given specification. Even though we prove facts about possible executions of programs, there is no need to appeal to branching time logics; we employ a fragment of linear temporal logic for our proofs. The method results in concise proofs of maximality for several non-trivial examples. The method may also serve as a guide in constructing maximal programs.
Class Refinement as Semantics of Correct Object Substitutability
Authors: Back Ralph-Johan , Mikhajlova Anna , von Wright Joakim 
Published: October 2002

Abstract.

Subtype polymorphism, based on syntactic conformance of objects' methods and used for substituting subtype objects for supertype objects, is a characteristic feature of the object-oriented programming style. While certainly very useful, typechecking of syntactic conformance of subtype objects to supertype objects is insufficient to guarantee correctness of object substitutability. In addition, the behaviour of subtype objects must be constrained to achieve correctness. In class-based systems classes specify the behaviour of the objects they instantiate. In this paper we define the class refinement relation which captures the semantic constraints that must be imposed on classes to guarantee correctness of substitutability in all clients of the objects these classes instantiate. Clients of class instances are modelled as programs making an iterative choice over invocation of class methods, and we formally prove that when a class
C
′ refines a class
C
, substituting instances of
C
′ for instances of
C
is refinement for the clients.
Algebraic Composition of Function Tables
Authors: von Mohrenschildt Martin 
Published: October 2002

Abstract.In general, a program is composed of smaller program segments using composition, conditional constructs or loop constructs. We present a theory which enables us to algebraically define and compute the composition of conditional expressions. The conditional expressions are represented using tabular notation. The formal definition of the composition allows us to compute the close form representation of the composition of tabular expressions. The presented approach is based on a many sorted algebra containing information preserving composition. This formal definition of composition is then “lifted” to an extended algebra containing tabular expressions. The presented theory provides very compact algorithms and proofs.
Value of preoperative coagulation tests: Reappraisal of major noncardiac surgery
Authors: Ng Kwok F. J. , Lai Kin W. , Tsang Suk F. 
Published: October 2002

AbstractIn a retrospective case‐control review, we evaluated preoperative coagulation testing in patients undergoing major noncardiac operations to determine if routine testing benefits this group of patients. The platelet count (PC), prothrombin time (PT), and activated partial thromboplastin time (aPTT) in all patients undergoing major noncardiac surgery over a 22‐month period were reviewed. The review was done both manually and by the computerized hospital information system. Major surgery was defined as procedures usually associated with significant bleeding. For each patient with abnormal results, another two control patients undergoing the same surgery and matched for age and gender were identified. Case and control patients were compared regarding a change in the management plan, use of blood products, blood loss, and bleeding complications by detailed chart review. A total of 828 patients undergoing nine different surgeries were reviewed. The incidence of abnormal PCs was 2.2% [95% confidence interval (CI) 1.2–3.2%] and that of abnormal PT/aPTTs was 2.1% (95% CI 1.1–3.1%). There were only two cases each of thrombocytopenia and prolonged PT/aPTT where the coagulation tests were not indicated clinically. Although (compared to controls) patients with abnormal tests had more changes in their anesthesia plan (36% vs. 2%, p<0.001) and platelet or fresh frozen plasma transfusions (50% vs. 9%, p<0.001), blood loss and the incidence of bleeding complications were not different. We conclude that the use of preoperative coagulation tests in patients undergoing major noncardiac surgery should still be guided by clinical assessment. The surgical procedure itself does not constitute an indication for testing.
Progesterone inhibits chloride transport in human intestinal epithelial cells
Authors: Mayol Julio M. , Arbeo‐Escolar Ana , Alarma‐Estrany Pilar , Adame‐Navarrete Yolanda , Fernández‐Represa Jesús A. 
Published: October 2002

AbstractSeveral pieces of evidence suggest that female sex hormones may play a role in the regulation of electrolyte transport. We therefore hypothesized that female sex hormones might impair regulated transcellular chloride transport in human intestinal epithelial cells. The T84 cell line was used for electrophysiological studies. Changes in transepithelial resistance and short‐circuit current (Isc) were measured via a dual voltage/current clamp in epithelial monolayers. Short‐circuit current is equivalent to chloride secretion in T84 cells. Forskolin and 8‐Br‐cyclic adenosine monophosphate (cAMP) were used to activate cAMP‐dependent Cl− transport. Ca2+‐dependent secretion was stimulated by the receptor‐mediated Ca2+ agonist carbachol. Acute exposure (30 minutes) to either progesterone or estradiol did not affect monolayer viability as reflected by transepithelial resistance. Moreover, the secretory response to both cAMP and Ca2+ agonists remained unaffected. In contrast, long‐term exposure (24 hours) to physiological concentrations of progesterone (100 nM), but not estradiol, dose‐dependently reduced the peak Isc induced by the cAMP‐agonist forskolin from 125±2.7 µA · cm−2 in the control group to 96±2.5 µA · cm−2 in monolayers exposed to progesterone (n=6 for each group; p<0.001). When the cAMP‐analogue 8‐Br‐cAMP was used, the same behavior was observed (peak Isc=112±1.6 µA · cm−2 vs 88±1.7 µA · cm−2 for control vs. progesterone‐treated monolayers; n=6 for each group; p<0.001). Taken together, our results suggest that progesterone but not estradiol inhibits cAMP‐stimulated Cl− secretion in intestinal epithelial cells at a site distal to cyclic nucleotide generation.