bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validations of CFD against detailed velocity and pressure measurements in water turbine runner flow
Authors: Nilsson H. , Davidson L. 
Published: February 2003

AbstractThis work compares CFD results with experimental results of the flow in two different kinds of water turbine runners. The runners studied are the GAMM Francis runner and the Hölleforsen Kaplan runner. The GAMM Francis runner was used as a test case in the 1989 GAMM Workshop on 3D Computation of Incompressible Internal Flows where the geometry and detailed best efficiency measurements were made available. In addition to the best efficiency measurements, four off‐design operating condition measurements are used for the comparisons in this work. The Hölleforsen Kaplan runner was used at the 1999 Turbine 99 and 2001 Turbine 99—II workshops on draft tube flow, where detailed measurements made after the runner were used as inlet boundary conditions for the draft tube computations. The measurements are used here to validate computations of the flow in the runner.The computations are made in a single runner blade passage where the inlet boundary conditions are obtained from an extrapolation of detailed measurements (GAMM) or from separate guide vane computations (Hölleforsen). The steady flow in a rotating co‐ordinate system is computed. The effects of turbulence are modelled by a low‐Reynolds number k‐ω turbulence model, which removes some of the assumptions of the commonly used wall function approach and brings the computations one step further.The computational results are compared to the measurements with respect to detailed velocity and pressure distributions at several measurement sections and several operating conditions. The computational results are also compared to coarse grid wall function computations by the TASCflow CFD code, which uses a similar methodology as the CALC‐PMB CFD code used in the present work. The comparisons show where the computational method is sufficient and where it is not sufficient.The behaviour of the computational method is similar for both kinds of water turbines, which shows that experience of computations in water turbines will ultimately give quantitatively correct results. Copyright © 2003 John Wiley & Sons, Ltd.
A new positive‐definite regularization of incompressible Navier–Stokes equations discretized with Q1/P0 finite element
Authors: Eguchi Yuzuru 
Published: February 2003

AbstractA new regularization method is proposed for the Galerkin approximation of the incompressible Navier–Stokes equations with Q1/P0 element, by newly introducing a square‐type linear form into the variational divergence‐free constraint regularized with the global pressure jump (GPJ) method. The addition of the square‐type linear form is intended to eliminate the hydrostatic pressure mode appearing in confined flows, and to make the discretized matrix positive definite and then non‐singular without the pressure pegging trick. Effects of the free parameters for the regularization on the solutions are numerically examined with a 2‐D driven cavity flow problem. Furthermore, the convergences in the conjugate gradient iteration for the solution of the pressure Poisson equation are compared among the mixed method, the GPJ method and the present method for both leaky and non‐leaky 3‐D driven cavity flows. Finally, the non‐leaky 3‐D cavity flows at different Re numbers are solved to compare with the literature data and to demonstrate the accuracy of the proposed method. Copyright © 2003 John Wiley & Sons, Ltd.
Option volume and volatility response to scheduled economic news releases
Authors: Nofsinger John R. , Prucyk Brian 
Published: February 2003

AbstractIn this article, we examine the impact of 21 different types of scheduled macroeconomic news announcements on
S&P 100 stock‐index option volume and implied volatility. We find that there is a 2‐h delay
after the announcement before volume increases. However, there is an immediate increase in volatility, which
slowly dissipates over several hours. Further analysis shows that most of the high volume and volatility after
announcements come from the announcements that are considered bad news. That is, bad news creates high
volatility and high volume, whereas good news elicits lower volume and is not associated with higher volatility.
These results are not consistent with the predictions of any one model. We also find that the announcements that
cause the largest reaction in the equity option market are Consumer Credit, Consumer Spending, Factory
Inventories, NAPM, and Non‐Farm Payrolls. Six other announcements elicit a mild response. © 2003
Wiley Periodicals, Inc. Jrl Fut Mark 23:315–345, 2003
The components of interest rate swap spreads: Theory and international evidence
Authors: Fehle Frank 
Published: February 2003

AbstractThis article contains both a theoretical and an empirical analysis of the components of interest rate swap
spreads defined as the difference between the fixed swap rate and the risk‐free rate of equal maturity.
The components are determined by expected LIBOR spreads, default risk, and market structure. A model of the swap
market incorporating debt market imperfections and corporate financing choices is used to explain participation
by both swap buyers and sellers. The model also motivates an empirical relationship between swap spreads and the
slope of the risk‐free term structure. The article then provides empirical evidence on the
cross‐sectional and time‐series variation of swap spreads in seven international markets. The
evidence is consistent with the suggested components across both markets and swap maturities as well as over
time. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:347–387, 2003
Volatility and trading demands in stock index futures
Authors: Pan Ming‐Shiun , Liu Y. Angela , Roth Herbert J. 
Published: February 2003

AbstractIn this study we examine how volatility and the futures risk premium affect trading demands for hedging and
speculation in the S&P 500 Stock Index futures contracts. To ascertain if different volatility measures matter
in affecting the result, we employ three volatility estimates. Our empirical results show a positive relation
between volatility and open interest for both hedgers and speculators, suggesting that an increase in volatility
motivates both hedgers and speculators to engage in more trading in futures markets. However, the influence of
volatility on futures trading, especially for hedging, is statistically significant only when spot volatility is
used. We also find that the demand to trade by speculators is more sensitive to changes in the futures risk
premium than is the demand to trade by hedgers. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:399–414,
2003
Futures hedging under mark‐to‐market risk
Authors: Lien Donald , Li Anlong 
Published: February 2003

AbstractThis article introduces mark‐to‐market risk into the conventional futures hedging framework. It
is shown that a hedger concerned with maximum daily loss will considerably reduce his futures position when the
risk is taken into account. In case of a moderate hedge horizon, the hedger will hedge approximately 80% of
his spot position.The effect of mark‐to‐market risk decreases very slowly as the hedge horizon increases. If the
hedger is concerned with average daily loss, the effect is minimal for a moderate hedge horizon. © 2003 Wiley
Periodicals, Inc. Jrl Fut Mark 23:389–398, 2003
Geophysical exploration of Guajará, a prehistoric earth mound in Brazil
Authors: Bevan Bruce W. , Roosevelt Anna C. 
Published: February 2003

AbstractAn interdisciplinary team studied Guajará, a prehistoric artificial mound in the Brazilian Amazon. The geophysical surveys and excavations were interactive;this interaction furnished more information than either geophysics or excavation alone could have provided. While seven different geophysical methods were applied, the magnetic survey reported here was particularly valuable. A detailed interpretation of this survey quantified the magnetic material in the mound, and this furnished an initial estimate of the number of cooking hearths in the mound. Ten test excavations were concentrated at magnetic anomalies. These excavations located cooking hearths and burial urns. A reevaluation of the magnetic survey was then done in order to refine the estimate of the number of hearths in the mound; this yielded an estimate of 2200 hearths. This allowed the population of the site to be approximated at 78–156 people. The geophysical survey and excavations also identified possible locations for subsequent broad‐area excavations. © 2003 Wiley Periodicals, Inc.
Short contribution: Nile flow failure at the end of the Old Kingdom, Egypt: Strontium isotopic and petrologic evidence
Authors: Stanley Jean‐Daniel , Krom Michael D. , Cliff Robert A. , Woodward Jamie C. 
Published: February 2003

AbstractStrontium isotopic and petrologic information, obtained from sediment cores collected in the Nile delta of Egypt, indicate that paleoclimatic and Nile baseflow conditions changed considerably from about 4200 to 4000 cal yr B.P. in the Nile basin. Our study records a higher proportion of White Nile sediment transported during the annual floods at ca. 6100 cal yr B.P. than towards 4200 cal yr B.P., at which time suspended sediment from the Blue Nile formed a significantly larger fraction of the total load. This resulted from a decrease in vegetative cover and an increase in erosion rate accompanying the marked decline in rainfall. These new geoscience data indicate major changes in annual flooding and baseflow of the river Nile, marked short‐term paleoclimatic‐related events that may in part have led to the collapse of the Old Kingdom. © 2003 Wiley Periodicals, Inc.
A 3.5 ka record of paleoenvironments and human occupation at Angkor Borei, Mekong Delta, southern Cambodia
Authors: Bishop Paul , Penny Dan , Stark Miriam , Scott Marian 
Published: February 2003

AbstractMicrofossil and sedimentological data from a 3.1 m core extracted from a reservoir (baray) at the ancient Cambodian settlement of Angkor Borei in the Mekong Delta have provided a continuous record of sedimentation and paleoenvironments dating from about 2000 cal yr B.C. Palynological data indicate that for much of the cal. 1st and 2nd millennia B.C. mangroves dominated the regional vegetation, while extensively and regularly burnt grasslands dominated the local vegetation. Turbid, nutrient‐rich standing water characterized the core locality, perhaps suggesting a connection with rivers in the area. An abrupt change during the cal. 5th to 6th centuries A.D. involved a dramatic reduction in grasslands and the expansion of secondary forest or re‐growth taxa. These changes are synchronous with an abrupt decline in the concentration of microscopic charcoal particles in the sediments, and the colonization of the core locality by swamp forest plants. These changes are taken to indicate a shift in land‐use strategies or, possibly, a period of land abandonment. The age for the construction of the baray is interpreted to be in the 17th–19th centuries, but this dating remains speculative. Construction of the Angkor Borei baray exploited a preexisting body of standing water, so its construction was fundamentally different from the methods used at the Angkorian capital in northern Cambodia. © 2003 Wiley Periodicals, Inc.
Geothermal activity at the archaeological site of Aghia Kyriaki and its significance to Roman industrial mineral exploitation on Melos, Greece
Authors: Hall A. J. , Photos‐Jones E. , McNulty A. , Turner D. , McRobb A. 
Published: February 2003

AbstractThe geothermal setting of the archaeological site at Aghia Kyriaki, Southeast Melos (or Milos) was investigated in order to help clarify the possible role of the site in mineral exploitation on Melos in Roman times. There are active sulfurous fumaroles in the area and these were also potential sources of sulfur and alum‐group minerals in Roman times. However, geothermal activity has been ongoing in Southeast Melos for hundreds of thousands of years, and extensive hydrothermal alteration of basement rocks to the northeast of the site has produced “white rocks” containing additional potential industrial minerals such as kaolin and alunite. The archaeological remains occur within, but mainly near the surface, of a deeply gullied sequence of late Quaternary alluvial sediments, which consist mainly of metamorphic detritus but are rich in sulfates; the remains contain pottery sherds through the entire sequence of about 40 m. They were deposited on an earlier gullied topography of felsic tuffs overlying the metamorphic basement. Pervasive and veinlike intense reddish alteration of these sediments is probably mainly due to superheated fluid escaping from depth. Field observations demonstrate that this took place after the main phase of building but was likely to be ongoing during occupation of the site. While industrial minerals and geothermal energy would therefore have been available in the Roman period, any relationship of the site to mineral exploitation will have to be determined by archaeological excavation. © 2003 Wiley Periodicals, Inc.
A cross‐linguistic fMRI study of perception of intonation and emotion in Chinese
Authors: Gandour Jack , Wong Donald , Dzemidzic Mario , Lowe Mark , Tong Yunxia , Li Xiaojian 
Published: February 2003

AbstractConflicting data from neurobehavioral studies of the perception of intonation (linguistic) and emotion (affective) in spoken language highlight the need to further examine how functional attributes of prosodic stimuli are related to hemispheric differences in processing capacity. Because of similarities in their acoustic profiles, intonation and emotion permit us to assess to what extent hemispheric lateralization of speech prosody depends on functional instead of acoustical properties. To examine how the brain processes linguistic and affective prosody, an fMRI study was conducted using Chinese, a tone language in which both intonation and emotion may be signaled prosodically, in addition to lexical tones. Ten Chinese and 10 English subjects were asked to perform discrimination judgments of intonation (I: statement, question) and emotion (E: happy, angry, sad) presented in semantically neutral Chinese sentences. A baseline task required passive listening to the same speech stimuli (S). In direct between‐group comparisons, the Chinese group showed left‐sided frontoparietal activation for both intonation (I vs. S) and emotion (E vs. S) relative to baseline. When comparing intonation relative to emotion (I vs. E), the Chinese group demonstrated prefrontal activation bilaterally; parietal activation in the left hemisphere only. The reverse comparison (E vs. I), on the other hand, revealed that activation occurred in anterior and posterior prefrontal regions of the right hemisphere only. These findings show that some aspects of perceptual processing of emotion are dissociable from intonation, and, moreover, that they are mediated by the right hemisphere. Hum. Brain Mapping 18:149–157, 2003. © 2003 Wiley‐Liss, Inc.
Neural systems of second language reading are shaped by native language
Authors: Tan Li Hai , Spinks John A. , Feng Ching‐Mei , Siok Wai Ting , Perfetti Charles A. , Xiong Jinhu , Fox Peter T. , Gao Jia‐Hong 
Published: February 2003

AbstractReading in a second language (L2) is a complex task that entails an interaction between L2 and the native language (L1). To study the underlying mechanisms, we used functional magnetic resonance imaging (fMRI) to visualize Chinese–English bilinguals' brain activity in phonological processing of logographic Chinese and alphabetic English, two written languages with a sharp contrast in phonology and orthography. In Experiment 1, we found that phonological processing of Chinese characters recruits a neural system involving left middle frontal and posterior parietal gyri, cortical regions that are known to contribute to spatial information representation, spatial working memory, and coordination of cognitive resources as a central executive system. We assume that the peak activation of this system is relevant to the unique feature of Chinese that a logographic character has a square configuration that maps onto a monosyllabic unit of speech. Equally important, when our bilingual subjects performed a phonological task on English words, this neural system was most active, whereas brain areas mediating English monolinguals' fine‐grained phonemic analysis, as demonstrated by Experiment 2, were only weakly activated. This suggests that our bilingual subjects were applying their L1 system to L2 reading and that the lack of letter‐to‐sound conversion rules in Chinese led Chinese readers to being less capable of processing English by recourse to an analytic reading system on which English monolinguals rely. Our brain imaging findings lend strongest support to the idea that language experience tunes the cortex. Hum. Brain Mapping 18:158–166, 2003. © 2003 Wiley‐Liss, Inc.
The time course of brain activity in reading English and Chinese: An ERP study of Chinese bilinguals
Authors: Liu Ying , Perfetti Charles A. 
Published: February 2003

AbstractChinese bilinguals performed a delayed naming task, reading both Chinese characters and English words, while EEGs were recorded by a 128‐channel system. Principle component analysis (PCA) of Event Related Potentials (ERP) from the onset of the stimulus suggested a temporal unfolding of graphic, phonological, and semantic processing that depended on both language and word frequency. At 150 msec, Chinese produced an earlier and higher amplitude shift (N150) than English. At 250 msec, frequency effects were significant for both Chinese and English, but at 450 msec, only the English frequency effect was reliable. Source localization analysis by Low Resolution Electromagnetic Tomography (LORETA) showed bilateral occipital (left BA 17, right BA 18) visual processing of Chinese characters with left occipital only (left BA 17) for English high‐frequency words. Low‐frequency English words showed activation bilaterally, but with a more diffused and extended temporal pattern. Right prefrontal area (BA 10) was found to be strongly activated in the mid latency (300–400 msec) period of Chinese character naming, whereas English word naming showed more medial frontal (BA 8, and 10) activation. A post 450‐msec visual verification was found to be general for both writing systems. Hum. Brain Mapping 18:167–175, 2003. © 2003 Wiley‐Liss, Inc.
Developmental aspects of language processing: fMRI of verbal fluency in children and adults
Authors: Gaillard William D. , Sachs Bonnie C. , Whitnah Joseph R. , Ahmad Zaaira , Balsamo Lyn M. , Petrella Jeffrey R. , Braniecki Suzanne H. , McKinney Christopher M. , Hunter Kevin , Xu Ben , Grandin Cecile B. 
Published: February 2003

AbstractWe examined developmental differences, in location and extent of fMRI language activation maps, between adults and children while performing a semantic fluency task. We studied 29 adults and 16 children with echo planar imaging BOLD fMRI at 1.5 T using covert semantic verbal fluency (generation of words to categories compared to rest) using a block design. Post task testing was administered to assess performance. Individual data were analyzed with an a priori region of interest approach from t maps (t = 4) and asymmetry indices (AI). Group studies were analyzed using SPM 99 (Wellcome, UK; fixed effect, corrected P < 0.0001). We found no significant differences in location or laterality of activation between adults and children for a semantic verbal fluency task. Adults activated more pixels than children in left inferior frontal gyrus and left middle frontal gyrus, but AIs were the similar across ages (r2 < 0.09). Extent or laterality of activation was not affected by performance (r2 < 0.15). The brain areas that process semantic verbal fluency are similar in children and adults. The laterality of activation does not change appreciably with age and appears to be strongly lateralized by age 7 years. Hum. Brain Mapping 18:176–185, 2003. © 2003 Wiley‐Liss, Inc. Published 2003 Wiley‐Liss, Inc.
Comparison of block and event‐related fMRI designs in evaluating the word‐frequency effect
Authors: Chee Michael W.L. , Venkatraman Vinod , Westphal Christopher , Siong Soon Chun 
Published: February 2003

AbstractPrinted word frequency can modulate retrieval effort in a task requiring associative semantic judgment. Event‐related fMRI, while avoiding stimulus order predictability, is in theory statistically less powerful than block designs. We compared one event‐related and two block designs that evaluated the same semantic judgment task and found that similar brain regions demonstrated the word frequency effect. Although the responses were lower in amplitude, event‐related fMRI was able to detect the word frequency effect to a comparable degree compared to the block designs. The detection of a frequency effect with the event‐related design also suggests that stimulus–order predictability may not be as serious a concern in block designs as might be supposed. Hum. Brain Mapping 18:186–193, 2003. © 2003 Wiley‐Liss, Inc.
Bilateral brain abnormalities associated with dominantly inherited verbal and orofacial dyspraxia
Authors: Belton Emma , Salmond Claire H. , Watkins Kate E. , Vargha‐Khadem Faraneh , Gadian David G. 
Published: February 2003

AbstractThe KE family is a large three‐generational pedigree in which half of the members suffer from a verbal and orofacial dyspraxia in association with a point mutation in the FOXP2 gene. This report extends previous voxel‐based morphometric analyses of magnetic resonance imaging (MRI) scans (Watkins et al. [2002] Brain 125:465–478) using a bilateral conjunction analysis. This searches specifically for areas of grey matter density that differ bilaterally in the affected members compared with both matched controls and the unaffected family members. 3‐D T1‐weighted MRI datasets of 17 family members (10 affected, 7 unaffected) and matched controls were compared. The most significant findings were reduced grey matter density bilaterally in the caudate nucleus, the cerebellum, and the left and right inferior frontal gyrus in the affected members. In addition, increased grey matter density was found bilaterally in the planum temporale. These results confirm that a point mutation in FOXP2 is associated with several bilateral grey matter abnormalities in both motor and language related regions. The results also demonstrate the advantages of using a conjunction analysis when bilateral abnormalities are suspected. Hum. Brain Mapping 18:194–200, 2003. © 2003 Wiley‐Liss, Inc.
Distinct brain regions associated with syllable and phoneme
Authors: Siok Wai Ting , Jin Zhen , Fletcher Paul , Tan Li Hai 
Published: February 2003

AbstractThe syllable and the phoneme are two important units in the phonological structure of speech sounds. In the brain mapping literature, it remains unsolved as to whether there are separate brain regions mediating the processing of syllables and phonemes. Using functional magnetic resonance imaging (fMRI), we investigated the neural substrate of these phonological units with Chinese subjects. Results revealed that the left middle frontal cortex contributes to syllabic processing, whereas the left inferior prefrontal gyri contributes to phonemic processing. This pattern of findings offers compelling evidence for distinct cortical areas relevant to the representation of syllables and phonemes. Hum. Brain Mapping 18:201–207, 2003. © 2003 Wiley‐Liss, Inc.