bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetics of sex pheromone blend differences between Heliothis virescens and Heliothis subflexa: a chromosome mapping approach
Authors: Sheck A. L. , Groot A. T. , Ward C. M. , Gemeno C. , Wang J. , Brownie C. , Schal C. , Gould F.
Published: October 2005

Males of the noctuid moths, Heliothis virescens and H. subflexa locate mates based on species-specific responses to female-emitted pheromones that are composed of distinct blends of volatile compounds. We conducted genetic crosses between these two species and used AFLP marker-based mapping of backcross families (H. subflexa direction) to determine which of the 30 autosomes in these moths contained quantitative trait loci (QTL) controlling the proportion of specific chemical components in the pheromone blends. Presence/absence of single H. virescens chromosomes accounted for 7–34% of the phenotypic variation among backcross females in seven pheromone components. For a set of three similar 16-carbon acetates, two H. virescens chromosomes interacted in determining their relative amounts within the pheromone gland and together accounted for 53% of the phenotypic variance. Our results are discussed relative to theories about population genetic processes and biochemical mechanisms involved in the evolution of new sexual communication systems.
Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA
Authors: Loehr J. , Worley K. , Grapputo A. , Carey J. , Veitch A. , Coltman D. W.
Published: October 2005

The separation of populations by ice sheets into large refugia can account for much of the genetic diversity found in present day populations. The evolutionary implications of small glacial refugia have not been as thoroughly explored. To examine refugial origins of North American mountain sheep Ovis spp., we analyzed a 604 bp portion of the mitochondrial DNA (mtDNA) control region from 223 O. dalli and O. canadensis. Major refugia were identified in eastern Beringia and southern North America, and we found evidence for two smaller refugia situated between the Laurentide and Cordilleran glaciers. Our results are the first to demonstrate support for survival of any organism in the latter two refugia. These refugia also appear to have conserved a genetic signal that confirms past hybridization of O. dalli and O. canadensis.
Pathogenesis of Parvovirus B19 Infection: Host Gene Variability, and Possible Means and Effects of Virus Persistence
Authors: Kerr J. R.
Published: October 2005

Since conducting follow‐up studies of patients with acute symptomatic parvovirus B19 infection which showed that a significant proportion of patients develop prolonged arthritis and chronic fatigue syndrome (CFS), we have become interested in the mechanisms of this phenomenon. We showed that these cases have high levels of pro‐inflammatory cytokines in their circulation and that this correlates with the symptoms. However, the underlying mechanisms were not apparent, and we have used various approaches to begin studying this phenomenon. DNA polymorphisms were looked for and several were shown to be more common in these subjects compared with controls; these occur within genes of both the immune response [human leucocyte antigen (HLA)‐DRB1, HLA‐B, transforming growth factor (TGF)‐β1] and those involved in several other cellular functions (predominantly the cytoskeleton and cell adhesion). Interestingly, one particular single‐nucleotide polymorphism (SNP) which is associated with symptomatic B19 infection occurs in the Ku80 gene which has recently been shown to be a B19 co‐receptor. B19 persistence is probably the key to this phenomenon, and some new data are presented on short regions of sequence homology (17–26 bp) between human, mouse and rat parvoviruses and their respective hosts which occur in many host genes. This homology may provide a foothold for virus persistence and may also play a role in the genesis of disease through gene disruption. Finally, we used microarrays and TaqMan real‐time polymerase chain reaction in 108 normal persons to study human gene expression in persons who are B19‐seropositive versus B19‐seronegative (age‐ and sex‐matched) to examine the hypothesis that gene regulation may be altered in subjects harbouring the B19 virus DNA. Six genes were found to be differentially expressed with roles in the cytoskeleton (SKIP, MACF1, SPAG7, FLOT1), integrin signalling (FLOT1, RASSF5), HLA class III (c6orf48), and tumour suppression (RASSF5). These results have implications not only for B19 but also for other persistent viruses as well and confirmation is required. In conclusion, these disparate findings contribute to our understanding of the pathogenesis of B19 disease. We are using these studies as a starting point to study the phenomenon of chronic immune activation following B19 infection.
New Approaches for the Molecular Characterization of Canine Parvovirus Type 2 Strains
Authors: Decaro N. , Elia G. , Campolo M. , Desario C. , Lucente M. S. , Bellacicco A. L. , Buonavoglia C.
Published: October 2005

Characterization of the canine parvovirus type 2 (CPV‐2) is sometimes ambiguous, frequently requiring more than one technique for definitive prediction of the viral type. Taking into account the single‐nucleotide polymorphisms encountered in the VP2‐protein gene between types 2a and 2b and between type 2b and Glu‐426 mutant (type 2c), two different minor groove binder (MGB) probe assays were developed for rapid identification of the CPV‐2 variants. A total of 315 samples collected from dogs with diarrhoea were screened for CPV‐2 by a real‐time polymerase chain reaction (PCR) assay capable of detecting all CPV‐2 types. In order to compare the type‐specific assays with the traditional techniques [haemagglutination inhibition with monoclonal antibodies, PCR‐restriction fragment‐length polymorphism (RFLP), sequence analysis] for prediction of CPV‐2 antigen specificity, the 203 samples tested CPV‐2 positive were analysed using the different methods. The results showed a 100% concordance between the MGB probe assays and the combined conventional methods, with 116 samples characterized as type 2a, 32 as type 2b and 55 as type 2c. Therefore, the MGB probe assays represent a quick, reliable tool for prediction of CPV‐2 antigen specificity, with regard to the more time‐consuming assays currently used.
Oncolytic Potential of Rodent Parvoviruses for Cancer Therapy in Humans: A Brief Review
Authors: Geletneky K. , Herrero y Calle M. , Rommelaere J. , Schlehofer J. R.
Published: October 2005

Rodent parvoviruses are promising candidates for oncolytic virotherapy of cancer in humans because of their oncotropism (preferential killing of transformed cells) in the absence of pathogenicity. Here, we give an overview concerning the possible application of parvovirus H‐1 for cancer therapy, with specific emphasis on malignant brain tumours in humans.
Analysis of the transmission of Salmonella spp. through generations of pet snakes
Authors: Schröter Matthias , Speicher Angelika , Hofmann Jörg , Roggentin Peter
Published: October 2005

Besides the ‘classical’ animals known as reservoirs for Salmonella spp., like poultry and cattle, reptiles have emerged as a significant source of human salmonellae infections during the last years. Reptile‐associated salmonellae frequently cause severe clinical courses including fatalities due to septicaemia and meningitis. Therefore, it is of major priority to develop measures which may help preventing cases of reptile‐associated salmonellae. However, as a first step the epidemiology of salmonellae in reptiles must be understood. Therefore, in this study a population analysis of the salmonellae of two female snakes was performed and the pattern of inheritance of salmonellae to their offspring was investigated. It is demonstrated that adult snakes usually harbour a population of concurrent salmonellae serovars. Colonization of their offspring during pregnancy and birth is a significant way of transmission causing 65% of the newborn to be positive for salmonellae. The effectiveness of the transmission does not seem to be due only to the frequency of a certain serovar, because the most prevailing strain of one female snake was not detectable in any of her offspring.
The m‐xylene biodegradation capacity of Pseudomonas putida mt‐2 is submitted to adaptation to abiotic stresses: evidence from expression profiling of xyl genes
Authors: Velázquez Francisco , De Lorenzo Víctor , Valls Marc
Published: October 2005

The effect of archetypal environmental stresses on expression of the catabolic xyl genes of the TOL plasmid pWW0 of the m‐xylene degrading strain Pseudomonas putida mt‐2 has been investigated. To this end, a subgenomic DNA chip was employed which included structural and regulatory DNA sequences of the TOL pathway along with selected descriptors of specific physiological conditions. Cells were separately exposed to m‐xylene under various oxygen tensions, temperatures and nitrogen sources as well as situations of DNA damage, oxidative stress, carbon and iron starvation, respiratory chain damage, and contact with arsenic, but at doses which did not cause a gross effect on growth or cell viability. The incidence of each stress class was categorized through the corresponding descriptors in the chip in respect to the relative output of xyl transcripts. While most of the stresses downregulated the m‐xylene biodegradation‐related genes, some uncouplers of the respiratory chain (azide) and small doses of arsenate appeared to stimulate their expression. The replacement of NH4+ by NO3– as N source augmented expression of the TOL cistrons also. We subsequently subjected P. putida mt‐2 cells to the multiple abiotic stress brought about by exposure to crude tar from the 2002 oil spill of the Prestige tanker, which embraces a complex mixture of hydrocarbons. The resulting expression profile of xyl genes and stress‐responding markers over time suggested that adaptation to external insults precedes any significant expression of the catabolic genes. The consequences of this hierarchy of responses for microbial biodegradation in situ are discussed.
The complaining client and the troubled therapist: a discursive investigation of family therapy
Authors: O'Reilly Michelle
Published: October 2005

In this paper I examine two important issues for family therapy research. I attend to the concept of complaints, highlighting the conversational structure they take in a family therapy setting. I do this by outlining how clients construct their complaints and examining how the family therapist receives them. Data is taken from a corpus containing four different families and two different therapists, and is subjected to discursive analysis in order to provide a rich analysis of not justwhatis happening in the talk buthowit is happening. I conclude that complaints are not received as useful to the therapeutic process, despite their constructed importance to the client, and therefore there are wider implications for therapy and professionals more generally, particularly implications for multi‐agency communication.
Ordering Top Pay: Interpreting the Signals*
Authors: Perkins Stephen J. , Hendry Chris
Published: October 2005

abstract  Boardroom reward continues to attract controversy, despite the structural changes in corporate governance arrangements over the past decade. This study responds to Pettigrew's (1992) call to eschew over‐ambitious attempts to demonstrate causality in the area of executive management and firm performance, in favour of redressing the overwhelmingly prescriptive bias in the literature. A simple but important task is to ‘begin to provide some basic descriptive findings about boards and their directors’, and open up ‘the black box of board behaviour’– in this case, that of board remuneration committees. Interpretations of comparative market signals play a part in deliberations between the leading actors responsible for determining executive directors’ salary, bonuses and other emoluments. But the position is more deeply textured than the reified influence of (global) market forces sometimes implied in the normative literature. The study reported, based on qualitative interviews, taps in to the nuances of decision taking in respect of boardroom reward management, including remuneration committee members’ reactions to corporate governance reforms. Such initiatives locate non‐executive directors in the role of intermediaries in the principal‐agent relationship, explicitly assigned to resolve the conflict of interest inherent in boardroom remuneration systems, while simultaneously they are expected to play a team role as board members responsible for the overall strategy and operation of the company. The study is indicative: an attempt to open up research questions around the context and process of boardroom reward management that earlier analyses may have ignored or overlooked.
‘Kindergarten Cop’: Paternalism and Resistance in a High‐Commitment Workplace*
Authors: Fleming Peter
Published: October 2005

abstract  This article investigates how organizational paternalism, often considered a traditional and rather archaic management style, is evoked by a culture management programme in order to increase control. Most research assumes that paternalism does successfully capture the subjective commitments of employees because they appreciate the ‘caring’ and ‘nurturing’ environment it engenders. Lacking in this literature is a consideration of how and why employees might resist organizational paternalism. An empirical study is presented that suggests some workers resist paternalism because it casts them as irrational children and undermines their dignity. The structure of this resistance is explored in detail and the relationships between paternalism, culture management and HRM examined.
Agency Problems in Diverse Contexts: A Global Perspective
Authors: Gomez‐Mejia Luis , Wiseman Robert M. , Dykes Bernadine Johnson
Published: October 2005

abstract  Bruce, Buck and Main (2005) offer two criticisms of agency theory as a valid model of executive behaviour. First, they suggest that because researchers have failed to find a strong empirical link between executive pay and firm performance, and since this research generally rests on models derived from agency theory, then we must question the theory. Second, they suggest that agency theory is under‐socialized and therefore lacks generalizability to settings where social solutions would seem to eliminate the agency problem. In our response we make three points. First, agency theory rests on an assumption of self‐interest that does not necessarily reflect opportunism. Second, agency theory does not make any reference to pay‐performance sensitivity, and the failure of this research can be attributable to a variety of problems with the research. Third, we agree that agency theory does not explicitly recognize contextual factors, but suggest that this abstraction from context, gives agency theory greater generalizability. Finally, we review the UK and German contexts discussed by Bruce, Buck and Main to show that socialized solutions do not prevent the occurrence of agency problems.
Foreign body post‐varicella granulomas due to talc
Authors: Lázaro C , Reichelt C , Lázaro J , Grasa MP , Carapeto FJ
Published: October 2005

Foreign body granulomas in the skin have been described frequently and may have various causes. Diagnosis is relatively easy in most cases, as most are related to foreign material penetrating into the skin due to different kinds of traumas. We present the case of a boy with multiple facial granulomas, persisting more than 6 months and related to the use of topical anti‐pruriginous talc powder applied to papuloexudative lesions caused by varicella. Data gathered in the anamnesis, examination with polarized light and images seen through the electron microscope enabled us to identify the causal agent talc as the inducer of the granulomatous lesions that the patient presented, discarding other types of foreign body granulomas of exogenous origin.
Efficacy of small group reading intervention for beginning readers with reading‐delay: a randomised controlled trial
Authors: Hatcher Peter J. , Hulme Charles , Miles Jeremy N.V. , Carroll Julia M. , Hatcher Janet , Gibbs Simon , Smith Glynnis , Bowyer‐Crane Claudine , Snowling Margaret J.
Published: October 2005

Background:  This study evaluated the effectiveness of an intervention for reading‐delayed children in Year‐1 classes.

Methods:  A sample (N = 77) of children drawn from 14 schools representing those with the weakest reading skills were randomly allocated to one of two groups. A 20‐week intervention group received the intervention for two consecutive 10‐week periods, while a 10‐week intervention group only received the intervention for the second 10 weeks of the study. The programme was delivered in daily 20‐minute sessions that alternated between small group (N = 3) and individual teaching. The programme combined phoneme awareness training, word and text reading, and phonological linkage exercises.

Results:  The children receiving the intervention during the first 10‐week period made significantly more progress on measures of letter knowledge, single word reading, and phoneme awareness than children not receiving the intervention. However, the children who only received the intervention during the second 10‐week period made rapid progress and appeared to catch up with the children who had been given the more prolonged intervention. Failure to respond to the intervention was predicted by poor initial literacy skills and being in receipt of free school meals.

Conclusion:  A reading intervention programme delivered on a daily basis by trained teaching assistants is an effective intervention for children who show reading delays at the end of their first year in school. However, around one‐quarter of the children did not respond to this intervention and these children would appear to need more intensive or more prolonged help to improve their reading skills.
Premature telomere shortening and impaired regenerative response in hepatocytes of individuals with NAFLD
Authors: Nakajima Tomoki , Moriguchi Michihisa , Katagishi Tatsuo , Sekoguchi Satoru , Nishikawa Taichiro , Takashima Hidetaka , Kimura Hiroyuki , Minami Masahito , Itoh Yoshito , Kagawa Keizo , Tani Yoichi , Okanoue Takeshi
Published: October 2005

Abstract: Aims: The risk factors associated with poor prognosis of nonalcoholic fatty liver disease (NAFLD) are not fully understood. Our aim was to assess the role of progressive hepatocellular telomere shortening in the clinical course of NAFLD.

Methods: We measured average telomere lengths in liver tissue samples from 44 patients with NAFLD by quantitative fluorescence in situ hybridization using a telomere‐specific probe. Patients in which telomeres measured at least 80% of the lengths of age‐matched controls were categorized as group A. Those patients with telomeres measuring less than 80% of the control lengths formed group B.

Results: Within group B, some samples showed a remarkable shortening of hepatocyte telomeres in younger patients, whereas some group A patients showed almost normal telomere lengths until their seventies. Among clinicopathological factors, body mass index (BMI), homeostasis model assessment insulin resistance (HOMA‐IR), histological degree of steatosis and intensity of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) immunostaining were all significantly higher in group B than in group A. Ki‐67 immunohistochemistry demonstrated that group B liver tissues were significantly less proliferative than those from group A, despite no significant difference in the necroinflammatory activities of group A and B samples. In group B patients, the ratios of Ki‐67 positive index to alanine aminotransferase value were significantly lower than group A.

Conclusions: Greater insulin resistance can result in more severe hepatic steatosis among group B patients, leading to an overproduction of reactive oxygen species, which may accelerate telomere erosion. Furthermore the regenerative response of hepatocytes with prominent telomere shortening may be impaired, making these cells vulnerable to the effect of a ‘second‐hit’ insult.
Appropriate Use of Information on Family History of Disease in Recruitment for Linkage Analysis Studies
Authors: Wallace C. , Clayton D.G.
Published: October 2005

When conducting genetic studies for complex traits, large samples are commonly required to detect any of the number of genes with relatively low effect thought to underly such traits. This is because, in contrast to monogenic diseases, complex traits typically result from a number of different genetic pathways (genetic heterogeneity) and any sample is likely to contain a considerable fraction of sporadic cases (phenocopies). Such samples are time‐consuming and costly to recruit and analyse. Methods which might be used to decrease sample size include attempting to select families, with the aim of reducing genetic heterogeneity or phenocopy rate within the sample. Selecting cases with positive family history of disease should reduce the phenocopy rate, and this strategy has been employed in linkage studies of complex disease, although evaluations of such a strategy have been equivocal.

This paper shows how identity by descent (IBD) distributions may be calculated for affected relative pairs recruited conditional on the affection status of a third relative. These distributions are then used to calculate expected power in affected sib and half‐sib linkage studies when recruitment is conditional on family history of disease. We consider the proxy conditions of recruitment conditional on disease in an affected parent or third sibling with single‐locus and additive multilocus genetic models. We show that while such selection strategies can reduce power if disease risk alleles are common and environmental heterogeneity low, under models more likely to underly common complex diseases power will generally be increased, and that this effect is greater as more loci are involved. Though the proxy cases studied are more extreme than a general strategy of asking potential recruits whether they have any family history of disease, these results suggest that conditional recruitment is more generally useful than previous studies have suggested.
Wicksell's Unaminity Rule
Authors: Johnson Marianne
Published: October 2005

Abstract  This paper identifies the extent to which James Buchanan's interpretation of Knut Wicksell’s unanimity rule, as spelled out in the second essay in Finanztheoretische Untersuchungen (1896), has come to dominate the public economics literature despite competing with the interpretation offered by Richard Musgrave. A brief summary of the differing interpretations is offered. Citation analysis is used to examine the frequency with which Wicksell is cited and by whom. The sociology of the economics profession and avenues for the dissemination of ideas are examined to understand the dominance of Buchanan's particular interpretation and application of the unanimity rule.
Future‐Oriented Gang Members?
Authors: Listokin Yair
Published: October 2005

Abstract  Two prominent theories of crime (Wilson and Herrnstein 1985; Gottfredson and Hirshi 1990) rely heavily on the notion that criminals are impatient or “present‐oriented.” In brief, the theories posit that present‐oriented individuals will be predisposed to crime because the “costs” of crime (e.g., prison time) lag behind crime's benefits. While the theory has intuitive appeal, it remains controversial. This study considers a data set first presented by Levitt and Venkatesh (2000) that details a drug‐selling gang's activities. In this gang, low‐ranking criminals accept low initial wages in the hope of receiving high future remunerations. As demonstrated in the note, this wage structure is exceedingly difficult to reconcile (both theoretically and empirically) with the notion of present‐oriented criminals. In sum, the study suggests that present orientation is at best an incomplete and idiosyncratic explanation of the causes of crime.
Initial response of a floodplain lake fish community to water‐level stabilisation
Authors: Pegg M. A. , Irons K. S. , O'Hara T. M. , McClelland M. A.
Published: October 2005

Abstract –  Many floodplain lake fish communities have been influenced by large‐scale shifts in processes of water‐level stability that degrade habitat quantity and quality. Efforts to restore rivers and their floodplains have recently taken a priority yet many restoration approaches are in their developmental stages and potentially controversial. We measured fish community changes in response to a water stabilisation technique in an Illinois River floodplain lake, achieved by levee renovations in 1997, using data collected prior to (1991–1993) and after (2000–2002) stabilisation. Our results indicate fish community composition (presence/absence) showed little variability and did not differ (R = 0.037; P = 0.60) between the two time periods; whereas, fish community structure (abundance) differed (R > 0.50; P ≤ 0.10). Increased abundances of desirable species like gizzard shad Dorosoma cepedianum (Lesueur), white crappie Pomoxis annularis (Rafinesque), black crappie Pomoxis nigromaculatus (Lesueur) and largemouth bass Micropterus salmoides (Lacepede), coupled with declines of less desirable species like common carp Cyprinus carpio (Linnaeus) contributed to community changes. These changes suggest positive responses to water stabilisation practices that may act as an intermediate step in restoring river–floodplain function in certain situations.
Shedding of the amyloid precursor protein‐like protein APLP2 by disintegrin‐metalloproteinases
Authors: Endres Kristina , Postina Rolf , Schroeder Anja , Mueller Ulrike , Fahrenholz Falk
Published: October 2005

Cleavage of the amyloid precursor protein (APP) within the amyloid‐beta (Aβ) sequence by the α‐secretase prevents the formation of toxic Aβ peptides. It has been shown that the disintegrin‐metalloproteinases ADAM10 and TACE (ADAM17) act as α‐secretases and stimulate the generation of a soluble neuroprotective fragment of APP, APPsα. Here we demonstrate that the related APP‐like protein 2 (APLP2), which has been shown to be essential for development and survival of mice, is also a substrate for both proteinases. Overexpression of either ADAM10 or TACE in HEK293 cells increased the release of neurotrophic soluble APLP2 severalfold. The strongest inhibition of APLP2 shedding in neuroblastoma cells was observed with an ADAM10‐preferring inhibitor. Transgenic mice with neuron‐specific overexpression of ADAM10 showed significantly increased levels of soluble APLP2 and its C‐terminal fragments. To elucidate a possible regulatory mechanism of APLP2 shedding in the neuronal context, we examined retinoic acid‐induced differentiation of neuroblastoma cells. Retinoic acid treatment of two neuroblastoma cell lines upregulated the expression of both APLP2 and ADAM10, thus leading to an increased release of soluble APLP2.
A NFKB1 promoter polymorphism is involved in susceptibility to ulcerative colitis
Authors: Borm M. E. A. , van Bodegraven A. A. , Mulder C. J. J. , Kraal G. , Bouma G.
Published: October 2005

Nuclear factor κB (NF‐κB) designates a group of critical transcription factors involved in a variety of immunologic and/or inflammatory processes. Conceivably, genes involved in the NF‐κB pathway make interesting candidate genes for chronic inflammatory disorders, including the inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC). In two mouse models of colitis, strong linkage has been observed with a locus on chromosome 3 that harbours the Nfkb1 gene. In addition, a polymorphism in the promoter region of the human NFKB1 gene was found to be associated with susceptibility to UC. In this study, we searched to confirm this previously found association in IBD in a different population. Allele and genotype frequencies of the −94 ins/delATTG polymorphism were determined in 266 unrelated Dutch Caucasian IBD patients (127 UC, 139 CD), and 155 matched healthy controls. The allele frequency of the deletion was significantly higher in UC patients (P = 0.019), but not in CD patients, compared to healthy controls, and the UC patients homozygous for the −94 ATTG deletion had a younger age of onset. Our findings confirm the previously found association between this polymorphism and susceptibility to UC in an independent study population and adds further evidence for the role of this gene in disease susceptibility.
Finite Element Analysis of the Thermal and Mechanical Behaviors of a Bolted Joint
Authors: Fukuoka Toshimichi
Published: October 2005

Mechanical and thermal behaviors of the bolted joint subjected to thermal load are analyzed using axisymmetric FEM, where the effects of thermal contact resistance at the interface and heat flow through small gap are taken into account in order to accurately evaluate the variations of bolt preloads. It is expected that the numerical procedure proposed here provides an effective means for estimating the strength of such critical structures as pressure vessels, internal combustion engines, steam and gas turbines, etc. An experimental equation that can compute the thermal contact coefficient at the interface composed of common engineering materials has been proposed in the previous paper. In this study, a simple equation for evaluating the amount of heat flow through small gap is shown by defining apparent thermal contact coefficient. Accordingly, a numerical approach has been established, which can accurately analyze the thermal and mechanical behaviors of a bolted joint, by incorporating the two kinds of thermal contact coefficients into FE formulation. By use of the FE code thus developed, it is shown that only a slight difference in coefficients of linear expansion among the joint members significantly affects the variations of bolt preloads. The validity of the numerical approach is demonstrated by experimentation.
Influence of Yield-to-Tensile Strength Ratio on Failure Assessment of Corroded Pipelines
Authors: Zhu Xian-Kui , Leis Brian N.
Published: October 2005

This paper investigates the influence of yield-to-tensile strength ratio (Y∕T) on failure pressure of pipelines without and with corrosion defects. Based on deformation instability and finite strain theory, a plastic collapse model for end-capped defect-free pipes is developed. The stress-strain response of materials is characterized by a power-law hardening curve, and the plastic deformation obeys the von Mises yield criterion and the deformation theory of plasticity. Two formulas to estimate the strain hardening exponent n for a specific Y∕T are obtained, and a closed-form solution to the limit pressure of pipes is derived as a function of Y∕T. This plastic collapse model is then extended to predict the failure pressure of pipelines with corrosion defects. Numerical and experimental comparisons are presented that validate the present models which characterize the influence of Y∕T on the failure behavior of pipeline.
Limit Load Analysis of Pipe Bend Using the R-Node Method
Authors: Fanous Ihab F. Z. , Adibi-Asl R. , Seshadri R.
Published: October 2005

The r-node method has been developed earlier as a technique to find the limit load using the Elastic Modulus Adjustment Procedures. It utilizes the systematic redistribution of the stress to find the load-controlled locations in a component to estimate the collapse load. In this paper, the method is shown to be applicable for multiple loads. A simple cantilever beam is analyzed using the redistribution-node (r-node) method subjected to both bending force and moment. The results compare well with the closed-form solution of the problem. The method is then used to estimate the limit load for an elbow subjected to in-plane and out-of-plane moment. The results compare well with the elastic-plastic analysis.
Effect of Geometry of Grooves on Connection Strength of Hydraulically Expanded Tube-to-Tubesheet Joints
Authors: Wang H. F. , Sang Z. F.
Published: October 2005

The object of this paper is to investigate the effect of the geometry of circumferential grooves on the connection strength of hydraulically expanded tube-to-tubesheet joints of heat exchangers. Seven-tube models with different groove widths, depths, spacings, and locations were fabricated under the same expansion pressure by commercial hydraulic expanders. Then the corresponding pullout forces were gained by experimental means. In addition, the process of hydraulic expansion of tube-to-tubesheet joints was simulated using the nonlinear finite element method based on a two-dimensional (2D) axisymmetrical model. The residual stress and deformation of joints were determined, and the effect of geometrical parameters of the grooves on the connection strength of joints was studied in terms of the average residual contact pressure of the joints. The experimental and calculation results indicate that the most important geometrical factor for determining the connection strength is the groove width. Groove depth, spacing, and location have a secondary effect. Optimum geometrical sizes of grooves are proposed based on maximum axial strength. These can provide a reference for the revision of design and manufacturing codes.
Effects and modeling of phonetic and acoustic confusions in accented speech
Authors: Fung Pascale , Liu Yi
Published: October 2005

Accented speech recognition is more challenging than standard speech recognition due to the effects of phonetic and acoustic confusions. Phonetic confusion in accented speech occurs when an expected phone is pronounced as a different one, which leads to erroneous recognition. Acoustic confusion occurs when the pronounced phone is found to lie acoustically between two baseform models and can be equally recognized as either one. We propose that it is necessary to analyze and model these confusions separately in order to improve accented speech recognition without degrading standard speech recognition. Since low phonetic confusion units in accented speech do not give rise to automatic speech recognition errors, we focus on analyzing and reducing phonetic and acoustic confusability under high phonetic confusion conditions. We propose using likelihood ratio test to measure phonetic confusion, and asymmetric acoustic distance to measure acoustic confusion. Only accent-specific phonetic units with low acoustic confusion are used in an augmented pronunciation dictionary, while phonetic units with high acoustic confusion are reconstructed using decision tree merging. Experimental results show that our approach is effective and superior to methods modeling phonetic confusion or acoustic confusion alone in accented speech, with a significant 5.7% absolute WER reduction, without degrading standard speech recognition.
An analytical prediction of the oscillation and extinction thresholds of a clarinet
Authors: Dalmont Jean-Pierre , Gilbert Joël , Kergomard Jean , Ollivier Sébastien
Published: October 2005

This paper investigates the dynamic range of the clarinet from the oscillation threshold to the extinction at high pressure level. The use of an elementary model for the reed-mouthpiece valve effect combined with a simplified model of the pipe assuming frequency independent losses (Raman’s model) allows an analytical calculation of the oscillations and their stability analysis. The different thresholds are shown to depend on parameters related to embouchure parameters and to the absorption coefficient in the pipe. Their values determine the dynamic range of the fundamental oscillations and the bifurcation scheme at the extinction.
High intensity focused ultrasound-induced gene activation in sublethally injured tumor cells in vitro
Authors: Liu Yunbo , Kon Takashi , Li Chuanyuan , Zhong Pei
Published: October 2005

Cultured human cervical cancer (HeLa) and rat mammary carcinoma (R3230Ac) cells were transfected with vectors encoding green fluorescent protein (GFP) under the control of hsp70B promoter. Aliquots of 10-μl transfected cells (5×107cells∕ml) were placed in 0.2-ml thin-wall polymerase chain reaction tubes and exposed to 1.1-MHz high intensity focused ultrasound (HIFU) at a peak negative pressure P−=2.68MPa. By adjusting the duty cycle of the HIFU transducer, the cell suspensions were heated to a peak temperature from 50to70°C in 1–10s. Exposure dependent cell viability and gene activation were evaluated. For a 5-s HIFU exposure, cell viability dropped from 95% at 50°C to 13% at 70°C. Concomitantly, gene activation in sublethally injured tumor cells increased from 4% at 50°C to 41% at 70°C. A similar trend was observed at 60°C peak temperature as the exposure time increased from 1to5s. Further increase of exposure duration to 10s led to significantly reduced cell viability and lower overall gene activation in exposed cells. Altogether, maximum HIFU-induced gene activation was achieved at 60°C in 5s. Under these experimental conditions, HIFU-induced gene activation was found to be produced primarily by thermal rather than mechanical stresses.
Conservative numerical methods for nonlinear strings
Authors: Bilbao Stefan
Published: October 2005

In this article, a class of numerical schemes for the simulation of nonlinear coupled longitudinal/transverse string vibration is presented. Though there are various ways of arriving at such schemes, special attention is paid here to energy conservation in nonlinear model systems and its transfer to an analogous discrete quantity in a difference scheme. Such exact numerical energy conservation can lead to simple global stability conditions, which can be otherwise difficult to ascertain for nonlinear difference schemes—in particular, such conditions may be arrived at without any reliance on frequency domain concepts (i.e., Fourier or Laplace transforms), which are of only moderate utility in the analysis of nonlinear systems. Implementation details are discussed and numerical results are presented.
The effect of diotic and dichotic level-randomization on the binaural masking-level difference
Authors: Henning G. Bruce , Richards Virginia M. , Lentz Jennifer J.
Published: October 2005

Detection thresholds for tones in narrow-band noise were measured for two binaural configurations: NoSo and NoSπ. The 30-Hz noise band had a mean overall level of 65dB SPL and was centered on 250, 500, or 5000Hz. Signals and noise were simultaneously gated for 500, 110, or 20ms. Three conditions of level randomization were tested: (1) no randomization; (2) diotic randomization—the stimulus level (common to both ears) was randomly chosen from an uniformly distributed 40-dB range every presentation interval; and (3) dichotic randomization—the stimulus levels for each ear were each independently and randomly chosen from the 40-dB range. Regardless of binaural configuration, level randomization had small effects on thresholds at 500 and 110ms, implying that binaural masking-level differences (BMLDs) do not depend on interaural level differences for individual stimuli. For 20-ms stimuli, both diotic and dichotic randomization led to markedly poorer performance than at 500- and 110-ms durations; BMLDs diminished with no randomization and dichotic randomization but not with diotic randomization. The loss of BMLDs at 20ms, with degrees-of-freedom (2WT) approximately 1, implies that changes in intracranial parameters occurring during the course of the observation interval are necessary for BMLDs when mean-level and mean-intracranial-position cues have been made unhelpful.
Profile analysis: The effects of rove on sparse spectra
Authors: Lentz Jennifer J.
Published: October 2005

Profile-analysis thresholds were measured in the presence and absence of overall level variation at different stimulus levels to determine whether nonlinear changes in the shape of the edges of excitation pattern peaks contribute to poorer spectral-shape sensitivity observed under roving levels. Roving levels decreased sensitivity for stimuli having few components separated widely in frequency to a greater extent than for stimuli having more densely spaced components. The stimulus level did not influence sensitivity when overall level variation was absent, suggesting that listeners rely on peaks in the excitation patterns and not the edges of the peaks (as would have been predicted by the near miss to Weber’s law). Because the edges of the peaks were not used in the absence of roving levels, it follows that the larger rove effects for sparse stimuli were not likely due to excitation pattern inconstancy.
Source localization in the Haro Strait primer experiment using arrival time estimation and linearization
Authors: Michalopoulou Zoi-Heleni , Ma Xiaoqun
Published: October 2005

Modeling sound propagation in the Haro Strait is a challenging task, the site being complex and the sediment structure exhibiting a strong range dependence. The environmental complexities create difficulties for source localization using matched field processing because many of the parameters needed for replica calculation are uncertain or rapidly varying. Received time series from signal propagation at the site provide a wealth of information that can be exploited for source localization obviating the need for extensive environmental knowledge. In this paper, a Gibbs sampling-maximum a posteriori estimator is used to extract the direct path, first surface bounce, and first bottom bounce arrival times from time series received at vertical line arrays. Those times provide source and receiving phone location and water column depth estimates through a set of linear relationships. Estimates obtained with the proposed method for data collected during the Haro Strait primer experiment are very close to reference values for the unknown parameters.
Two-dimensional axisymmetric numerical simulation of supercritical phase conjugation of ultrasound in active solid media
Authors: Bou Matar Olivier , Preobrazhensky Vladimir , Pernod Philippe
Published: October 2005

In the present study a two-dimensional axisymmetric numerical model is developed for supercritical parametric phase conjugation of ultrasound in a solid active element of cylindrical shape and finite length. The pseudospectral time domain algorithm (PSTD) is used owing to its efficiency to model large-scale problems. PSTD solves elastic wave equation in time-dependent heterogeneous isotropic and axisymmetric anisotropic solids using FFTs for high order approximation of the spatial differential operator on staggered grid, and a fourth-order Adams–Bashforth time integrator. In order to truncate the computational domain absorbing boundary conditions are introduced with complex frequency shifted perfectly matched layers. This procedure is highly effective at absorbing signals of long time-signature. The free surface of the active ceramic rod is introduced through the method of images. A systematic study of the influence of lateral limitations of the active medium on parametric wave phase conjugation of sound is made. It is shown that retro-focusing of the incident pulse takes place even in the case of mode conversions inside the active zone. Nevertheless, amplitude and form of the obtained conjugate pulse depend on the simulated configuration. Numerical simulation correctly describes the parametric amplification and retro-focusing of ultrasound observed in experiments.
On three-dimensional edge waves in semi-infinite isotropic plates subject to mixed face boundary conditions
Authors: Kaplunov J. , Prikazchikov D. A. , Rogerson G. A.
Published: October 2005

This paper is concerned with the propagation of three-dimensional waves localized near the edge of a semi-infinite elastic plate subject to mixed face boundary conditions. In the linear isotropic case it is shown that the problem is closely related to that of Rayleigh surface wave propagation along the free surface of the corresponding half-space. The cut-off frequencies of the analyzed edge waves coincide with the natural frequencies of the associated cross-sectional semi-infinite strip. It is also demonstrated that the eigenspectrum of a rectangular rod can be expressed in terms of the considered three-dimensional waves. The results are then generalized to a prestressed isotropic incompressible material. It is noted that the density of the edge wave spectrum is strongly influenced by the prestress. It is illustrated that the areas of negative group velocity may exist for large primary deformation. Long-wave asymptotic expansions in the vicinity of the cut-off frequencies are presented.
Consonant identification in N-talker babble is a nonmonotonic function of N
Authors: Simpson Sarah A. , Cooke Martin
Published: October 2005

Consonant identification rates were measured for vowel-consonant-vowel tokens gated with N-talker babble noise and babble-modulated noise for an extensive range of N, at a fixed signal-to-noise ratio. In the natural babble condition, intelligibility was a nonmonotonic function of N, with a broad performance minimum from N=6 to N=128. Identification rates in babble-modulated noise fell gradually with N. The contributions of factors such as energetic masking, linguistic confusion, attentional load, peripheral adaptation, and stationarity to the perception of consonants in N-talker babble are discussed.
Computation of the temperature distortion in the stack of a standing-wave thermoacoustic refrigerator
Authors: Marx David , Blanc-Benon Philippe
Published: October 2005

The numerical computation of the flow and heat transfer in the vicinity of a stack plate in a standing wave refrigerator is performed. Temperature distortion is observed, which appears only in the stack region, even if the acoustic standing wave outside the stack is itself sinusoidal. The distortion takes place above the whole plate surface when the length of the plate is equal to or shorter than four times the particle displacement. This condition may occur at high drive ratios and is favored by plate positions close to the velocity antinode. The thermal distortion decreases the thermoacoustic heat pumping along the plate. At high drive ratios, if the length of the plate is not large enough, the thermal distortion can typically explain a difference of about 10% between the calculated heat flux and the heat flux predicted using linear theory.
Sound-field analysis by plane-wave decomposition using spherical microphone array
Authors: Park Munhum , Rafaely Boaz
Published: October 2005

Directional sound-field information is becoming more important in sound-field analysis and auditorium acoustics, and, as a consequence, a variety of microphone arrays have recently been studied that provide such information. In particular, spherical microphone arrays have been proposed that provide three-dimensional information by decomposing the sound field into spherical harmonics. The theoretical formulation of the plane-wave decomposition and array performance analysis were also presented. In this paper, as a direct continuation of the recent work, a spherical microphone array configured around a rigid sphere is designed, analyzed using simulation, and then used experimentally to decompose the sound field in an anechoic chamber and an auditorium into waves. The array employs a maximum of 98 measurement positions around the sphere, and is used to compute spherical harmonics up to order 6. In the current paper we investigate the factors affecting the performance of plane-wave decomposition, showing that the direct sound and several reflections in an auditorium can be identified experimentally. This suggests that the microphone arrays studied here can be employed in various acoustic applications to identify the characteristics of reverberant sound fields.