bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Computer Investigation of the Performance of Virtual Reflectors: Part II — The Effects of Room Conditions
Authors: Oldham D.J. , El-Zeky L. 
Published: October 2002

In a companion paper [1] a technique for overcoming acoustic problems resulting from the directional nature of human speech in open stage auditoria by means of virtual reflectors has been proposed. In a following paper [2] the system was applied to a computer model of an open stage auditorium in which there was no background noise and the space was relatively dead. In the current paper the action of the virtual reflector has been systematically investigated in more realistic conditions. It is shown to be capable of functioning in conditions which are more reverberant and in conditions in which background noise is present. In all cases investigated the action of a virtual reflector results in conditions to the rear of the primary source (human speaker) being improved such that they become comparable to conditions at equivalent positions to the front. It has been shown that the STI at the rear of a human speaker in an open stage auditorium with the virtual reflector system in operation does not increase significantly with increasing gain [2]. This is due to the Modulation Transfer Function (MTF's) being determined by the convolution of two impulse responses multiplied by a gain factor and added to a third impulse response. The resulting impulse response will therefore consists of many ‘reflections’ and hence the MTF's (and the STI values that they determine) will be adversely affected. An attempt was made to reduce the number of ‘reflections’ in the resultant impulse response by the use of a super directional microphone in order to improve the MTF's and thus the STI values. The actual improvement observed was very small and hence it would appear that the use of a super directional microphone is not particularly effective in this context.
The Image Source-Virtual Barrier Model for Prediction of Reflection Effects from Barriers
Authors: Cheng W.F. , Ng C.F. 
Published: October 2002

This study employed a computer program to identify the insertion loss degradation of barrier due the reflection. The mathematical theories of single barrier prediction are based on Maekawa prediction [1], which predicts the attenuation produced by the barrier as a function of geometry and frequency. The single image source concept was used for estimating the reflection effect of the second barrier. A scale model of a scale 1:20 and a line source made of small speakers were used to verify the accuracy of the computer program. The results from the program agree well with those of scale models. The results show that the region of where the illuminated zone of the virtual source and the shadow zone of the primary source overlap (Ys1 < Y < Ys) is the critical region of noise degradation. Thus, the image source model with a virtual barrier is a very useful and straight-forward tool for the design of parallel barriers. Four barrier design parameters have been analyzed; sound source position, barrier height, distance between parallel barriers and the usefulness of absorptive material applied at the second barrier.
Sound Transmission through Hollow Brick Walls
Authors: Fringuellino M. , Smith R.S. 
Published: October 2002

Hollow bricks and blocks are one of the most common forms of material used for wall construction found in Central and Southern Europe. The principle purpose of the perforations (holes) is to increase the thermal insulation properties. As a result of these perforations the block gross density is reduced significantly and these block walls have high anisotropy. Consequently, the acoustical insulation properties are influenced detrimentally in comparison to solid blocks. Due to the large thickness of some of these types of hollow block thick wall effects can occur such as bending shear waves and thickness resonances. These further reduce the sound insulation at high frequencies. This paper describes the characteristic features of sound transmission through hollow walls. For this study several different types of wall were built of varying thickness and materials and the sound reduction index was recorded. The effects of additional plaster layers is also discussed. It is suggested that the material properties of the block's complex web structure may strongly influence the sound reduction index at the low and high frequencies.
Signalling among relatives. I. Is costly signalling
too
costly?
Authors: Bergstrom Carl T. , Lachmann Michael 
Published: October 2002

Zahavi's handicap principle,originally proposed as an explanation for sexual selection ofelaborate male traits, suggests that a sufficient cost to dishonest signals can outweigh the rewards of deception and allow individuals to communicate honestly. Maynard Smith (1991) and Johnstone and Grafen (1992) introduce the Sir Philip Sidney game in order to extend the handicap principle to interactions among related individuals, and to demonstrate that stable costly signalling systems can exist among relatives.
In this paper we demonstrate that despite the benefits associated with honest information transfer, the costs incurred in a stable costly signalling system may leave all participants worse off than they would be in a system with no signalling at all. In both the discrete and continuous forms of the Sir Philip Sidney game, there exist conditions under which costly signalling among relatives, while stable, is so costly that it is disadvantageous compared with no signalling at all. We determine the factors which dictate signal cost and signal benefit in a generalized version of this game, and explain how signal cost can exceed signal value. Such results raise concerns about theevolutionary pathways which could have led to the existence of signalling equilibria in nature. The paper stresses the importance of comparing signalling equilibria with other possible strategies, beforedrawing conclusions regarding the optimality of signalling.
The epidemiology of BSE in cattle herds in Great Britain. I. Epidemiological processes, demography of cattle and approaches to control by culling
Authors: Donnelly C. A. , Ferguson N. M. , Ghani A. C. , Woolhouse M. E. J. , Watt C. J. , Anderson R. M. 
Published: October 2002

This paper explores the key epidemiological processes and demographic factors that determined the pattern of transmission of the aetiological agent of bovine spongiform encephalopathy (BSE) in cattle herds in Great Britain (GB). The analyses presented utilize data from published and unpublished experimental studies and from the GB central database of confirmed BSE cases.We review the experimental and epidemiological evidence that has both confirmed indirect horizontal transmission via the consumption of infectious material as the major transmission route and provided information on the duration and variability of the dose–dependent incubation period of BSE in cattle. The epidemiological and genetic data pertaining to the possible existence of maternal transmission and/or genetically variable susceptibility to infection is discussed.The demography of British cattle is characterized and the impacts of key demographic features on the observed epidemic profile are discussed. In the main BSE case database, analyses reveal that BSE cases cluster significantly at both the holding and county scale. Furthermore, analysis of longitudinal patterns reveal substantial temporal within–holding correlation. Such clustering of cases suggests a highly heterogeneous infection process.The paper ends with a discussion of how analyses of spatio–temporal clustering inform the design of targeted culling programmes aimed at reducing future disease incidence. We show how the retrospective implementation of culling policies on the BSE case database allows the qualitative evaluation of policy performance, but that model predictions of future trends in case incidence are required to estimate the precise impact of any current or future programme.
Interactions between plant nutrients, water and carbon dioxide as factors limiting crop yields
Authors: Gregory P. J. , Simmonds L. P. , Warren G. P. 
Published: October 2002

Biomass production of annual crops is often directly proportional to the amounts of radiation intercepted, water transpired and nutrients taken up. In many places the amount of rainfall during the period of rapid crop growth is less than the potential rate of evaporation, so that depletion of stored soil water is commonplace. The rate of mineralization of nitrogen (N) from organic matter and the processes of nutrient loss are closely related to the availability of soil water. Results from Kenya indicate the rapid changes in nitrate availability following rain.
Nutrient supply has a large effect on the quantity of radiation intercepted and hence, biomass production. There is considerable scope for encouraging canopy expansion to conserve water by reducing evaporation from the soil surface in environments where it is frequently rewetted, and where the unsaturated hydraulic conductivity of the soil is sufficient to supply water at the energy limited rate (e.g. northern Syria). In regions with high evaporative demand and coarse–textured soils (e.g. Niger), transpiration may be increased by management techniques that reduce drainage.

Increases in atmospheric [CO
2
] are likely to have only a small impact on crop yields when allowance is made for the interacting effects of temperature, and water and nutrient supply.
The three pillars of the new family
Authors: Young Michael 
Published: October 2002

Children are the chief sufferers from the growing fragility of marriages and partnerships. They may also suffer from their mothers going out to paid work unless satisfactory alternative arrangements are made for their care, for instance, by bringing in grandparents to look after their grandchildren when the mothers are not at home. Grandparents may also have an important role when parents separate. There is a dearth of facts about what actually happens. The part played by grandparents has been touched on, but nothing more, in the course of studies in baby care and baby–sitting and the repercussions of the illness of the mother.
A Grandparent Commission is proposed to set in motion some of the necessary research and to review official policy as it affects grandparents. If grandparents already do a lot for children, and could do more, a measure of optimism about the future of the family could succeed the prevailing pessimism.
Functional Cloning, Sorting, and Expression Profiling of Nucleic Acid-Binding Proteins
Authors: Ramanathan Y. , Zhang Haibo , Aris Virginie , Soteropoulos Patricia , Aaronson Stuart A. , Tolias Peter P. 
Published: October 2002

A major challenge in the post-sequencing era is to elucidate the activity and biological function of genes that reside in the human genome. An important subset includes genes that encode proteins that regulate gene expression or maintain the structural integrity of the genome. Using a novel oligonucleotide-binding substrate as bait, we show the feasibility of a modified functional expression-cloning strategy to identify human cDNAs that encode a spectrum of nucleic acid-binding proteins (NBPs). Approximately 170 cDNAs were identified from screening phage libraries derived from a human colorectal adenocarcinoma cell line and from noncancerous fetal lung tissue. Sequence analysis confirmed that virtually every clone contained a known DNA- or RNA-binding motif. We also report on a complementary sorting strategy that, in the absence of subcloning and protein purification, can distinguish different classes of NBPs according to their particular binding properties. To extend our functional annotation of NBPs, we have used GeneChip expression profiling of 14 different breast-derived cell lines to examine the relative transcriptional activity of genes identified in our screen and cluster analysis to discover other genes that have similar expression patterns. Finally, we present strategies to analyze the upstream regulatory region of each gene within a cluster group and select unique combinations of transcription factor binding sites that may be responsible for dictating the observed synexpression.[The following individual kindly provided reagents, samples, or unpublished information as indicated in the paper: M. Stempher.]
Parallel Identification of New Genes in Saccharomyces cerevisiae
Authors: Oshiro Guy , Wodicka Lisa M. , Washburn Michael P. , Yates John R. , Lockhart David J. , Winzeler Elizabeth A. 
Published: October 2002

Short open reading frames (ORFs) occur frequently in primary genome sequence. Distinguishing bona fide small genes from the tens of thousands of short ORFs is one of the most challenging aspects of genome annotation. Direct experimental evidence is often required. Here we use a combination of expression profiling and mass spectrometry to verify the independent transcription of 138 and the translation of 50 previously nonannotated genes in the Saccharomyces cerevisiae genome. Through combined evidence, we propose the addition of 62 new genes to the genome and provide experimental support for the inclusion of 10 previously identified genes.[The following individuals kindly provided reagents, samples, or unpublished information as indicated in the paper: V. Velculescu. Supplementary material is available online at http://www.genome.org.]
The Drosophila Gene Collection: Identification of Putative Full-Length cDNAs for 70% of D. melanogaster Genes
Authors: Stapleton Mark , Liao Guochun , Brokstein Peter , Hong Ling , Carninci Piero , Shiraki Toshiyuki , Hayashizaki Yoshihide , Champe Mark , Pacleb Joanne , Wan Ken , Yu Charles , Carlson Joe , George Reed , Celniker Susan , Rubin Gerald M. 
Published: October 2002

Collections of full-length nonredundant cDNA clones are critical reagents for functional genomics. The first step toward these resources is the generation and single-pass sequencing of cDNA libraries that contain a high proportion of full-length clones. The first release of the Drosophila Gene Collection Release 1 (DGCr1) was produced from six libraries representing various tissues, developmental stages, and the cultured S2 cell line. Nearly 80,000 random 5′ expressed sequence tags (5′ expressed sequence tags [ESTs]from these libraries were collapsed into a nonredundant set of 5849 cDNAs, corresponding to ∼40% of the 13,474 predicted genes in Drosophila. To obtain cDNA clones representing the remaining genes, we have generated an additional 157,835 5′ ESTs from two previously existing and three new libraries. One new library is derived from adult testis, a tissue we previously did not exploit for gene discovery; two new cap-trapped normalized libraries are derived from 0–22-h embryos and adult heads. Taking advantage of the annotated D. melanogaster genome sequence, we clustered the ESTs by aligning them to the genome. Clusters that overlap genes not already represented by cDNA clones in the DGCr1 were analyzed further, and putative full-length clones were selected for inclusion in the new DGC. This second release of the DGC (DGCr2) contains 5061 additional clones, extending the collection to 10,910 cDNAs representing >70% of the predicted genes inDrosophila.[The sequence data described in this paper have been submitted to the GenBank data library under accession nos. BF485518-BF503517, BF503521-BF506780, BG631888-BG631996,BG633696-BG637540, BG640063-BG641469, BI141709-BI142246,BI161485-BI173971, BI212109-BI216987, BI227448-BI233322,BI234009-BI243989, BI351612-BI354228, BI354231-BI355901,BI355935-BI358751, BI361285-BI376197, BI481532-BI487261,BI563331-BI593695, BI604243-BI620155, BI620158-BI635012,BI635064-BI638027, and BI638030-BI642053. The following individuals kindly provided reagents, samples, or unpublished information as indicated in the paper: J. Pringle and M. Fuller.]
In Vivo Interactions between Photosynthesis, Mitorespiration, and Chlororespiration in Chlamydomonas reinhardtii
Authors: Cournac Laurent , Latouche Gwendal , Cerovic Zoran , Redding Kevin , Ravenel Jacques , Peltier Gilles 
Published: October 2002

Abstract
Interactions between photosynthesis, mitochondrial respiration (mitorespiration), and chlororespiration have been investigated in the green alga Chlamydomonas reinhardtiiusing flash illumination and a bare platinum electrode. Depending on the physiological status of algae, flash illumination was found to induce either a fast (t1/2 ≈ 300 ms) or slow (t1/2 ≈ 3 s) transient inhibition of oxygen uptake. Based on the effects of the mitorespiratory inhibitors myxothiazol and salicyl hydroxamic acid (SHAM), and of propyl gallate, an inhibitor of the chlororespiratory oxidase, we conclude that the fast transient is due to the flash-induced inhibition of chlororespiration and that the slow transient is due to the flash-induced inhibition of mitorespiration. By measuring blue-green fluorescence changes, related to the redox status of the pyridine nucleotide pool, and chlorophyll fluorescence, related to the redox status of plastoquinones (PQs) in C. reinhardtii wild type and in a photosystem I-deficient mutant, we show that interactions between photosynthesis and chlororespiration are favored when PQ and pyridine nucleotide pools are reduced, whereas interactions between photosynthesis and mitorespiration are favored at more oxidized states. We conclude that the plastid oxidase, similar to the mitochondrial alternative oxidase, becomes significantly engaged when the PQ pool becomes highly reduced, and thereby prevents its over-reduction.
High-Stearic and High-Oleic Cottonseed Oils Produced by Hairpin RNA-Mediated Post-Transcriptional Gene Silencing
Authors: Liu Qing , Singh Surinder P. , Green Allan G. 
Published: October 2002

Abstract
We have genetically modified the fatty acid composition of cottonseed oil using the recently developed technique of hairpin RNA-mediated gene silencing to down-regulate the seed expression of two key fatty acid desaturase genes, ghSAD-1-encoding stearoyl-acyl-carrier protein Δ9-desaturase andghFAD2-1-encoding oleoyl-phosphatidylcholine ω6-desaturase. Hairpin RNA-encoding gene constructs (HP) targeted against either ghSAD-1 or ghFAD2-1 were transformed into cotton (Gossypium hirsutum cv Coker 315). The resulting down-regulation of the ghSAD-1 gene substantially increased stearic acid from the normal levels of 2% to 3% up to as high as 40%, and silencing of the ghFAD2-1gene resulted in greatly elevated oleic acid content, up to 77% compared with about 15% in seeds of untransformed plants. In addition, palmitic acid was significantly lowered in both high-stearic and high-oleic lines. Similar fatty acid composition phenotypes were also achieved by transformation with conventional antisense constructs targeted against the same genes, but at much lower frequencies than were achieved with the HP constructs. By intercrossing the high-stearic and high-oleic genotypes, it was possible to simultaneously down-regulate both ghSAD-1 and ghFAD2-1to the same degree as observed in the individually silenced parental lines, demonstrating for the first time, to our knowledge, that duplex RNA-induced posttranslational gene silencing in independent genes can be stacked without any diminution in the degree of silencing. The silencing of ghSAD-1 and/or ghFAD2-1 to various degrees enables the development of cottonseed oils having novel combinations of palmitic, stearic, oleic, and linoleic contents that can be used in margarines and deep frying without hydrogenation and also potentially in high-value confectionery applications.
Inhibition of Phospholipase Dα byN-Acylethanolamines
Authors: Austin-Brown Shea L. , Chapman Kent D. 
Published: October 2002

Abstract
N-Acylethanolamines (NAEs) are endogenous lipids in plants produced from the phospholipid precursor,N-acylphosphatidylethanolamine, by phospholipase D (PLD). Here, we show that seven types of plant NAEs differing in acyl chain length and degree of unsaturation were potent inhibitors of the well-characterized, plant-specific isoform of PLD—PLDα. It is notable that PLDα, unlike other PLD isoforms, has been shown not to catalyze the formation of NAEs fromN-acylphosphatidylethanolamine. In general, inhibition of PLDα activity by NAEs increased with decreasing acyl chain length and decreasing degree of unsaturation, such thatN-lauroylethanolamine andN-myristoylethanolamine were most potent with IC50s at submicromolar concentrations for the recombinant castor bean (Ricinus communis) PLDα expressed inEscherichia coli and for partially purified cabbage (Brassica oleracea) PLDα. NAEs did not inhibit PLD from Streptomyces chromofuscus, and exhibited only moderate, mixed effects for two other recombinant plant PLD isoforms. Consistent with the inhibitory biochemical effects on PLDα in vitro,N-lauroylethanolamine, but not lauric acid, selectively inhibited abscisic acid-induced closure of stomata in epidermal peels of tobacco (Nicotiana tabacum cv Xanthi) andCommelina communis at low micromolar concentrations. Together, these results provide a new class of biochemical inhibitors to assist in the evaluation of PLDα physiological function(s), and they suggest a novel, lipid mediator role for endogenously produced NAEs in plant cells.
Complex Formation of Myrosinase Isoenzymes in Oilseed Rape Seeds Are Dependent on the Presence of Myrosinase-Binding Proteins
Authors: Eriksson Susanna , Andréasson Erik , Ekbom Barbara , Granér Georg , Pontoppidan Bo , Taipalensuu Jan , Zhang Jiaming , Rask Lars , Meijer Johan 
Published: October 2002

Abstract
The enzyme myrosinase (EC 3.2.3.1) degrades the secondary compounds glucosinolates upon wounding and serves as a defense to generalist pests in Capparales. Certain myrosinases are present in complexes together with other proteins such as myrosinase-binding proteins (MBP) in extracts of oilseed rape (Brassica napus) seeds. Immunhistochemical analysis of wild-type seeds showed that MBPs were present in most cells but not in the myrosin cells, indicating that the complex formation observed in extracts is initiated upon tissue disruption. To study the role of MBP in complex formation and defense, oilseed rape antisense plants lacking the seed MBPs were produced. Western blotting and immunohistochemical staining confirmed depletion of MBP in the transgenic seeds. The exclusive expression of myrosinase in idioblasts (myrosin cells) of the seed was not affected by the down-regulation of MBP. Using size-exclusion chromatography, we have shown that myrosinases with subunit molecular masses of 62 to 70 kD were present as free dimers from the antisense seed extract, whereas in the wild type, they formed complexes. In accordance with this, MBPs are necessary for myrosinase complex formation of the 62- to 70-kD myrosinases. The product formed from sinalbin hydrolysis by myrosinase was the same whether MBP was present or not. The performance of a common beetle generalist (Tenebrio molitor) fed with seeds, herbivory by flea beetles (Phyllotreta undulata) on cotyledons, or growth rate of the Brassica fungal pathogens Alternaria brassicae or Lepthosphaeria maculans in the presence of seed extracts were not affected by the down-regulation of MBP, leaving the physiological function of this protein family open.