bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retrofit of pre‐Northridge steel moment‐resisting frames using fluid viscous dampers
Authors: Uriz P. , Whittaker A. S. 
Published: August 2002

AbstractThis paper describes a study of the use of linear fluid viscous damping devices for the seismic retrofit of a three‐storey, pre‐Northridge steel‐framed building. Four part‐perimeter moment frames resisted lateral forces in the building. One of the four perimeter frames was analysed using static pushover, incremental dynamic and nonlinear dynamic analysis to calculate likely beam plastic rotations in design and maximum earthquakes. Ten 10–50 (design) and two 2–50 (maximum) earthquake histories were used for the nonlinear dynamic analysis. The maximum beam plastic rotations exceeded 0·020 radian for some of the design‐earthquake histories and 0·045 radian for one of the maximum‐earthquake histories. Fluid viscous dampers were added to the frame using the procedures of FEMA 273 with the goal of eliminating plastic rotations in the beams of the frame in the design earthquake. Average reductions in the displacement of the frame by a factor exceeding 2 were achieved in the design earthquake with the addition of approximately 40% equivalent viscous damping. Although plastic rotations in the beams were substantially reduced, they were not eliminated for 7 of the 10 characterizations of the design earthquake; the calculated maximum beam plastic rotations exceeded the measured plastic rotation capacity of pre‐Northridge steel moment‐frame connections and so some fractures of the beam connections in this frame would not be unexpected. The addition of the dampers to the building frame led to substantial increases in the maximum base shear and column axial forces, which in practice would likely lead to strengthening of the columns and the foundations. The average maximum axial forces in the dampers calculated by response‐history analysis exceeded the values calculated using the first‐mode procedure of FEMA 273. Higher‐mode effects must be considered using either response‐history analysis or the procedures of FEMA 274 to adequately size and detail fluid viscous dampers and their connections to the structural framing. Copyright © 2001 John Wiley & Sons, Ltd.
Examination of Alternaria alternata mutagenicity and effects of nitrosylation using the Ames Salmonella test
Authors: Schrader T. J. , Cherry W. , Soper K. , Langlois I. , Vijay H.M. 
Published: August 2002

AbstractMolds of the genus Alternaria are common food pathogens responsible for the spoilage of fruits, vegetables, grains, and nuts. Although consumption of Alternaria alternata‐contaminated foodstuffs has been implicated in an elevated incidence of esophageal carcinogenesis, the mutagenic potencies of several A. alternata toxins seem unable to account for the levels of activity found using crude mycelial extracts. In this study, the mutagenic effects of nitrosylation were examined with the major Alternaria metabolites Altenuene (ALT), Alternariol (AOH), Alternariol Monomethyl Ether (AME), Altertoxin I (ATX I), Tentoxin (TENT), Tenuazonic Acid (TA), and Radicinin (RAD) using the Ames Salmonella strains TA98 and TA100. In the absence of nitrosylation, ATX I was mutagenic when tested from 1 to 100 μg/plate in TA98 with rat liver S9 for activation, while AOH and ATX I were weakly mutagenic ± S9 in TA100. Incubation with nitrite generally increased mutagenic potencies with ATX I strongly mutagenic ± S9 in both TA98 and TA100, while ALT, AOH, AME, and RAD responses were enhanced in TA100 + S9. However, subsequent examination of three extracts made from A. alternata culture broth, acetone‐washed mycelia, and the acetone washes showed a different mutagenic response with both broth and acetone washes directly mutagenic in TA98 and TA100 but with a reduced response + S9. The acetone‐washed mycelial extract was found to have the lowest mutagenic activity of the three extracts tested. Nitrosylation had little effect on the mutagenicity of any of the extracts. Thus, while nitrosylation increases the mutagenicity of ATX I, and to a lesser extent that of several other Alternaria toxins, the results demonstrate that Alternaria produces a major mutagenic activity with a S. typhimurium response different from that found with the purified toxins. Efforts are currently underway to chemically identify this mutagenic species. Teratogenesis Carcinog. Mutagen. 21:261‐274, 2001. Published 2001 Wiley‐Liss, Inc.
Cytogenetic study of chronic ethanol consumption in rats
Authors: Tavares D.C. , Cecchi A.O. , Jordão A.A. , Vannucchi H. , Takahashi C.S. 
Published: August 2002

AbstractEthanol was supplied in the drinking water of Wistar rats at a concentration of 20% v/v for up to 30 days. The animals treated with ethanol demonstrated a nonsignificant increase in chromosomal aberration frequency when compared with control animals. The mitotic index values obtained indicated no significant differences between ethanol treatment and control groups. The final weights of control rats were significantly greater than those of the ethanol‐treated group. Chronic administration of ethanol showed no clastogenic or cytotoxic effect. After chronic ethanol consumption, the cytochromes P450 activity increases, thus possibly preventing the ethanol that has entered the circulation from reaching excessive levels, leading to metabolic adaptation and/or tolerance. Teratogenesis Carcinog. Mutagen. 21:361–368, 2001. © 2001 Wiley‐Liss, Inc.
Comparing the epistemological underpinnings of students' and scientists' reasoning about conclusions
Authors: Hogan Kathleen , Maglienti Mark 
Published: August 2002

AbstractThis study examined the criteria that middle school students, nonscientist adults, technicians, and scientists used to rate the validity of conclusions drawn by hypothetical students from a set of evidence. The groups' criteria for evaluating conclusions were considered to be dimensions of their epistemological frameworks regarding how knowledge claims are justified, and as such are integral to their scientific reasoning. Quantitative and qualitative analyses revealed that the responses of students and nonscientists differed from the responses of technicians and scientists, with the major difference being the groups' relative emphasis on criteria of empirical consistency or plausibility of the conclusions. We argue that the sources of the groups' differing epistemic criteria rest in their different spheres of cultural practice, and explore implications of this perspective for science teaching and learning. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 663–687, 2001
Science education in urban settings: Seeking new ways of praxis through critical ethnography
Authors: Barton Angela Calabrese 
Published: August 2002

AbstractThe challenges faced in urban science education are deeply rooted in the ongoing struggle for racial, class and gender equity. Part of this struggle is tied to huge differences in class and involves making more equitable the distribution of resources. Another part of this struggle is tied to the rich diversity of children who attend urban schools and involves generating new ways of understanding, valuing, and genuinely incorporating into school‐based practices the culture, language, beliefs, and experiences that these children bring to school. Thus, this article argues that to address these two challenges—and indeed to achieve a more just science education for all urban students— explicitly political research methodologies must be considered and incorporated into urban education. One potential route for this is critical ethnography, for this kind of methodology emerges collaboratively from the lives of the researcher and the researched and is centrally about praxis and a political commitment to the struggle for liberation and in defense of human rights. In making this argument, I have drawn from stories from my own research with homeless children. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 899–917, 2001
Young women's scientific identity formation in an urban context
Authors: Brickhouse Nancy W. , Potter Jennifer T. 
Published: August 2002

AbstractIn this article we examine the scientific identity formation of two young women of color who attend an urban vocational high school. One young woman lives in an urban setting, while the other lives in a suburban setting. We describe how these young women's identities influence and respond to experiences in school science. In particular, we describe how the experience of marginalization can make membership in a school science community impossible or undesirable. We also describe the advantages that accrue to students who fit well with the ideal identities of an urban school. Finally, we describe some of the difficulties students face who aspire to scientific or technological competence yet do not desire to take on aspects of the identities associated with membership in school science communities. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 965–980, 2001
International expansion of e‐retailers: Where the Amazon flows
Authors: Chakrabarti Rajesh , Scholnick Barry 
Published: August 2002

AbstractCompetition among e‐retailers is becoming increasingly intense and continuously narrowing margins. We
examine the price competition between Amazon and Barnes & Noble to illustrate this. The key to survival,
therefore, lies in rapidly expanding market size in one or both of two ways: expansion across product lines and
international expansion. Although foreign consumers can easily access an online retailer's website, high
cross‐border shipping costs often put foreign e‐retailers at a disadvantage. We show how, in spite of
being a superior store in most respects, Amazon fails to compete with the leading Canadian online book retailer,
Chapters Online, primarily because of cross‐border shipping disadvantages. Consequently e‐retailers
are using traditional foreign direct investment (FDI)‐based strategies to expand internationally.
In addition, a new mode of foreign market entry—e‐mediation—involving match‐making between
customers and suppliers in a country through a website located in another country, is also emerging. This is
particularly suitable in situations where protectionist barriers forbid FDI‐based strategies. Amazon plans to
use this strategy in Canada. © 2002 John Wiley & Sons, Inc.
Co‐production of microcystins and aeruginopeptins by natural cyanobacterial bloom
Authors: Harada Ken‐ichi , Mayumi Tsuyoshi , Shimada Takayuki , Fujii Kiyonaga , Kondo Fumio , Park Ho‐dong , Watanabe Mariyo F. 
Published: August 2002

AbstractThe relationship between Microcystis composition and the production of microcystins and nontoxic peptides in bloom cells, which was regularly collected in Lake Suwa, Japan, in the summer season from 1991 to 1994, was investigated. In order to determine the structures of the nontoxic peptides, we collected large amounts of bloom materials from the same lake on July 23, 1991, and isolated three nontoxic peptides. They were named as aeruginopeptins 917S‐A, ‐B, and ‐C, and their structures were mainly determined by a mass spectrometry/mass spectrometry (MS/MS) technique as 19‐membered cyclic depsipeptides possessing the Ahp (3‐amino‐6‐hydroxy‐2‐piperidone) moiety. An analysis of the microcystins and aeruginopeptins in the collected bloom cells and their Microcystis composition suggested that the M. aeruginosa large cell size produces both microcystins and aeruginopeptins, and the production of both compounds is genetically closely related. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 298–305, 2001
Differential space–time modulation for DS‐CDMA systems
Authors: Liu Jianhua , Li Jian 
Published: August 2002

AbstractDifferential space–time modulation (DSTM) schemes were recently proposed to fully exploit the transmit and receive antenna diversities without the need for channel state information. DSTM is attractive in fast flat fading channels since accurate channel estimation is difficult to achieve. In this paper, we propose a new modulation scheme to improve the performance of DS‐CDMA systems in fast time‐dispersive fading channels. This scheme is referred to as the differential space–time modulation for DS‐CDMA (DST‐CDMA) systems. The new modulation and demodulation schemes are especially studied for the fast fading down‐link transmission in DS‐CDMA systems employing multiple transmit antennas and one receive antenna. We present three demodulation schemes, referred to as the differential space–time Rake (DSTR) receiver, differential space–time deterministic (DSTD) receiver, and differential space–time deterministic de‐prefix (DSTDD) receiver, respectively. The DSTD receiver exploits the known information of the spreading sequences and their delayed paths deterministically besides the Rake‐type combination; consequently, it can outperform the DSTR receiver, which employs the Rake‐type combination only, especially for moderate‐to‐high SNR. The DSTDD receiver avoids the effect of intersymbol interference and hence can offer better performance than the DSTD receiver. Copyright © 2001 John Wiley & Sons, Ltd.
Total reflection by synchrotron radiation: trace determination in nuclear materials
Authors: Simabuco S. M. , Vázquez C. , Boeykens S. , Barroso R. C. 
Published: August 2002

AbstractThe chemical control of impurities in nuclear materials is indispensable in order to ensure efficient operation of the reactors. The maximum concentration admitted depends on the elements and in most cases is in the parts per billion range. Conventional analytical methods require a preconcentration treatment of the sample and a previous separation of the matrix (uranium). In this work, we investigated the use of total reflection x‐ray fluorescence with synchrotron radiation excitation as an alternative methodology for the determination of impurities in nuclear materials, namely K, Ca, Ti, Cr, Mn, Fe, Ni, Cu and As. The detection limits obtained were in the range 0.1–20 ng ml−1 for a 1000 s counting time. Copyright © 2002 John Wiley & Sons, Ltd.
Disruption and phenotypic analysis of six open reading frames from chromosome VII of Saccharomyces cerevisiae reveals one essential gene
Authors: Guerreiro Paulo , Rodrigues‐Pousada Claudina 
Published: August 2002

AbstractSix open reading frames (ORFs) located on chromosome VII of Saccharomyces cerevisiae (YGR205w, YGR210c, YGR211w, YGR241c, YGR243w and YGR244c) were disrupted in two different genetic backgrounds using short‐flanking homology (SFH) gene replacement. Sporulation and tetrad analysis showed that YGR211w, recently identified as the yeast ZPR1 gene, is an essential gene. The other five genes are non‐essential, and no phenotypes could be associated to their inactivation. Two of these genes have recently been further characterized: YGR241c (YAP1802) encodes a yeast adaptor protein and YGR244c (LSC2) encodes the β‐subunit of the succinyl‐CoA ligase. For each ORF, a replacement cassette with long flanking regions homologous to the target locus was cloned in pUG7, and the cognate wild‐type gene was cloned in pRS416. Copyright © 2001 John Wiley & Sons, Ltd.
Saccharomyces cerevisiae YCRO17c/CWH43 encodes a putative sensor/transporter protein upstream of the BCK2 branch of the PKC1‐dependent cell wall integrity pathway
Authors: Martin‐Yken Helene , Dagkessamanskaia Adilia , De Groot Piet , Ram Arthur , Klis Frans , François Jean 
Published: August 2002

AbstractThe Saccharomyces cerevisiae cwh43‐2 mutant, originally isolated for its Calcofluor white hypersensitivity, displays several cell wall defects similar to mutants in the PKC1–MPK1 pathway, including a growth defect and increased release of β‐1,6‐glucan and β‐glucosylated proteins into the growth medium at increased temperatures. The cloning of CWH43 showed that it corresponds to YCR017c and encodes a protein with 14–16 transmembrane segments containing several putative phosphorylation and glycosylation sites. The N‐terminal part of the amino acid sequence of Cwh43p shows 40% similarity with the mammalian FRAG1, a membrane protein that activates the fibroblast growth factor receptor of rat osteosarcoma (FGFR2‐ROS) and with protein sequences of four uncharacterized ORFs from Caenorhabditis elegans and one from Drosophila melanogaster. The C‐terminus of Cwh43p shows low similarities with a xylose permease of Bacillus megaterium and with putative sugar transporter from D. melanogaster, and has 52% similarity with a protein sequence from a Schizosaccharomyces pombe cDNA. A Cwh43–GFP fusion protein suggested a plasma membrane localization, although localization to the internal structure of the cells could not be excluded, and it concentrates to the bud tip of small budded cells and to the neck of dividing cells. Deletion of CWH43 resulted in cell wall defects less pronounced than those of the cwh43‐2 mutant. This allele‐specific phenotype appears to be due to a G–R substitution at position 57 in a highly conserved region of the protein. Genetic analysis places CWH43 upstream of the BCK2 branch of the PKC1 signalling pathway, since cwh43 mutations were synthetic lethal with pkc1 deletion, whereas the cwh43 defects could be rescued by overexpression of BCK2 and not by high‐copy‐number expression of genes encoding downstream proteins of the PKC1 pathway However, unlike BCK2, whose disruption in a cln3 mutant resulted in growth arrest in G1, no growth defect was observed in a double cwh43 cln3 mutants. Taken together, it is proposed that CWH43 encodes a protein with putative sensor and transporter domains acting in parallel to the main PKC1‐dependent cell wall integrity pathway, and that this gene has evolved into two distinct genes in higher eukaryotes. Copyright © 2001 John Wiley & Sons, Ltd.
The KlCYC1 gene, a downstream region for two differentially regulated transcripts
Authors: Angeles Freire‐Picos M. , Lombardía‐Ferreira Luís J. , Ramil Elvira , González‐Domínguez Mónica , Esperanza Cerdán M. 
Published: August 2002

AbstractKlCYC1 encodes for cytochrome c in the yeast Kluyveromyces lactis and is transcribed in two mRNAs with different 3′‐processing points. This is an uncommon transcription mechanism in yeast mRNAs. The 3′ sequence encompassing the whole region that is needed to produce both mRNAs is analysed. We have determined identical processing points in K.lactis and in Saccharomyces cerevisiae cells transformed with KlCYC1; positions 698 and 1092 (with respect to the TAA) are the major polyadenylation points. This shows that the cis‐elements present in the KlCYC1 3′‐untranslated region (3′‐UTR) direct a processing mechanism that has been conserved in yeast. In K. lactis there is a high predominance of the shorter transcript (1.14 kb) only at the initial logarithmic growth phase. Interestingly, this growth phase‐dependent regulation of 3′‐UTR processing is lost when the gene is expressed in S. cerevisiae. Copyright © 2001 John Wiley & Sons, Ltd.
Genetic analysis of the karyotype instability in natural wine yeast strains
Authors: Carro David , Piña Benjamin 
Published: August 2002

AbstractYeast strains isolated from the wild may show high rates of changes in their karyotypes during vegetative growth. We analysed over 500 karyotypes from mitotic and meiotic derivatives of strain DC5, which has a chromosome rearrangement rate of 8.2×10−3 changes/generation. About 70% of the meiotic derivatives of DC5 had low rearrangement rates, with an average of 5.8×10−4 changes/generation, suggesting that karyotype instability behaved as a dominant phenotype. Diploid derivatives with low karyotype variability in mitosis also had low rates of chromosomal rearrangement during meiosis, suggesting that the two phenotypes may be linked. DC5 and some of its meiotic derivatives (both with high and low karyotype variability) had chromosome XII hypervariable bands. Their distribution among the meiotic products indicates that they are not indicators for genetic instability. To our knowledge, data in this paper are the first to indicate that karyotypically unstable yeast strains may give stable progeny at high rates. Understanding of the relevant mechanism(s) may allow the design of genetic strategies to stabilize karyotypes from natural and/or industrial wine yeasts with unacceptable karyotype rearrangement rates. Copyright © 2001 John Wiley & Sons, Ltd.
ZRC – A Refinement Calculus for Z
Authors: Cavalcanti Ana , Woodcock Jim 
Published: August 2002

Abstract.
The fact that Z is a specification language only, with no associated program development method, is a widely recognised problem. As an answer to that, we present ZRC, a refinement calculus based on Morgan's work that incorporates the Z notation and follows its style and conventions. This work builds upon existing refinement techniques for Z, but distinguishes itself mainly in that ZRC is completely formalised. In this paper, we explain how programs can be derived from Z specifications using ZRC. We present ZRC-L, the language of our calculus, and its conversion laws, which are concerned with the transformation of Z schemas into programs of this language. Moreover, we present the weakest precondition semantics of ZRC-L, which is the basis for the derivation of the laws of ZRC. More than a refinement calculus, ZRC is a theory of refinement for Z.
Formal Performance Modelling and Evaluation of an Adaptive Mechanism for Packetised Audio over the Internet
Authors: Bernardo Marco , Gorrieri Roberto , Roccetti Marco 
Published: August 2002

Abstract.
A case study is presented which concerns the design of an adaptive mechanism for packetised audio for use over the Internet. During the design process, the audio mechanism was modelled with the stochastically timed process algebra EMPA and analysed via simulation by the EMPA based software tool TwoTowers in order to predict the percentage of packets that are received in time for being played out. The predicted performance figures obtained from the algebraic model illustrated in advance the adequacy of the approach adopted in the design of the audio playout delay control mechanism. Based on these performance figures, it was possible to implement and develop the complete mechanism without incurring additional costs due to the late discovery of unexpected errors or inefficiency. Performance results obtained from experiments conducted on the field confirmed the predictive simulative results.
The Changing Face of Standardization: A Place for Formal Methods?
Authors: Duce David , Duke David , Faconti Giorgio , Herman Ivan 
Published: August 2002

Abstract.
Many of the reported experiences in the industrial use of formal methods concern the development of products or product families, where the utility of the method is linked to direct savings in development costs or improved assurance of quality. However, one other area in which formal description techniques make a valuable contribution is in the development and documentation of International Standards, where the cost of using formal methods can be paid off both through increased quality of products that implement a given standard, and through the improved inter-operability of different implementations that comes from having a precise definition of the expected behaviour of a conforming implementation. Standards development, however, has some significant differences from product development, and comes with specific needs and constraints that affect the use of formal description techniques. This paper describes the role that formal methods played in the development of a new standard for distributed multimedia presentation. It describes a number of issues that arose from this experience, and which have longer term importance for formal methods in standards, particularly given the changes that are taking place in the way that standards are developed.