bluuebunny/crossref_metadata_2025 huggingface dataset:
Do Language‐Based Processing Tasks Separate Children with Language Impairment from Typical Bilinguals?
Authors: Kohnert Kathryn , Windsor Jennifer , Yim Dongsun
Published: February 2006

We report results from 2 language‐based processing tasks designed to investigate the performance of linguistically diverse learners. The tasks were the Competing Language Processing Task (CLPT) and Non‐Word Repetition (NWR). Participants were 100 school‐age children in 1 of 3 different experimental groups: monolingual English‐speaking children with specific or primary language impairment (LI), typical English‐only‐speaking children (EO), or typical Spanish–English bilingual children (BI). On both CLPT and NWR, EO group performance was best and LI group performance was poorest, with BI group performance falling in between. Likelihood ratios indicated that performance on these tasks does not provide compelling diagnostic power for separating typically developing bilinguals from monolingual children with LI. One exception is that children who obtained an NWR score of 93 percent or higher could be ruled out of the LI group with a high degree of confidence.
Oral Language and Reading in Bilingual Children
Authors: Miller Jon F. , Heilmann John , Nockerts Ann , Iglesias Aquiles , Fabiano Leah , Francis David J.
Published: February 2006

This article examines the question: Do lexical, syntactic, fluency, and discourse measures of oral language collected under narrative conditions predict reading achievement both within and across languages for bilingual children? More than 1,500 Spanish–English bilingual children attending kindergarten–third grade participated. Oral narratives were collected in each language along with measures of Passage Comprehension and Word Reading Efficiency. Results indicate that measures of oral language in Spanish predict reading scores in Spanish and that measures of oral language skill in English predict reading scores in English. Cross‐language comparisons revealed that English oral language measures predicted Spanish reading scores and Spanish oral language measures predicted English reading scores beyond the variance accounted for by grade. Results indicate that Spanish and English oral language skills contribute to reading within and across languages.
Processing Narratives for Verbatim and Gist Information by Adults with Language Learning Disabilities: A Functional Neuroimaging Study
Authors: Plante Elena , Ramage Amy E. , Magloire Joël
Published: February 2006

How verbal information is processed and recalled appears to be influenced by the structure of the information presented (e.g., unrelated sentences vs. narratives) and the processes the listener uses to encode the information (e.g., verbatim encoding vs. gist extraction). Twenty adults, half with a history of learning disabilities (HLD) and half without (control group) received functional magnetic resonance imaging (fMRI) scans. Participants were instructed to listen to narrative passages for either the exact wording or the general meaning of the narratives and respond to questions about the narratives. These conditions were contrasted with listening to randomly arranged sentences. Adults in the HLD group responded to test questions less accurately than the control group. Likewise, the HLD group showed physiological differences during both narrative and sentence processing in comparison to the control group. Both groups showed differences in processing narratives for gist versus verbatim information, which involved activation centered over the right precentral sulcus. The results support the notion that distinct aspects of verbal processing draw differentially on a distributed physiological network and that adults selected for HLD show both behavioral and physiological differences on narrative processing tasks. However, these differences are not necessarily qualitative in nature.
Bidirectional Ventricular Tachycardia with Alternating Right and Left Bundle Branch Block Morphology in a Patient with Metastatic Cardiac Tumors
Authors: DORFMAN FÁBIO KIRZNER , MESAS CÉZAR EUMANN , CIRENZA CLÁUDIO , DE PAOLA ANGELO AMATO VINCENZO
Published: February 2006

A case is reported of bidirectional ventricular tachycardia and syncope in a 16‐year‐old male with a previous history of a paratesticular rhabdomyosarcoma that achieved complete remission with treatment. At the electrophysiological study, frequent ectopy of both right and left bundle branch block pattern were present, with runs of monomorphic and bidirectional VT alternating the two morphologies. The study suggested a single focus at the interventricular septum with two exit sites, depolarizing the right and left ventricle in an alternate fashion. Reassessment of the malignancy status showed multiple cardiac metastases with a 4 mm nodule at the interventricular septum.
Recruitment of First‐Generation Latinos in a Rural Community: The Essential Nature of Personal Contact
Authors: RODRÍGUEZ MELANIE DOMENECH , RODRÍGUEZ JESÚS , DAVIS MELISSA
Published: February 2006

The purpose of this article is to report on the success of various recruitment activities for a behavioral observation study with Spanish‐speaking Latino families in a rural community in the western United States. Recruitment activities are pivotal to research to research because the enormous impact to the quality of the sample and, thus, the quality of the answers to the questions posed by the research. Recruitment can be especially challenging for researchers working with ethnic minorities due to a historical legacy of mistreatment by researchers that has led to healthy reticence to participate in research investigations. The present research presented unique challenges in that the data collection (1) took place in a rural community, (2) sought participation of a recent immigrant population, and (3) required videotaping. Data were collected from 50 families in a western rural community. After multiple recruitment strategies were used, the research team learned that word of mouth and use of existing community resources were the most powerful recruitment strategies. However, participant reports suggest that the other recruitment strategies helped familiarize participants with the study and potentially strengthened the influence of word of mouth referrals. Important differences were found between the easy‐to‐recruit and the hard‐to‐recruit samples within this study that support engagement in multiple recruitment strategies.
Complex Love as Relational Nurturing: An Integrating Ultramodern Concept
Authors: LINARES JUAN LUIS
Published: February 2006

This article is based on the description of therapy with a family in which three members had been given a serious psychiatric diagnosis: a schizophrenic disorder, a borderline personality disorder, and an antisocial personality disorder. The underlying hypothesis was that these disorders were related to the specific ways in which the obstruction of relational nurturing had influenced the turbulent history of the family. The therapy aimed to reopen channels of nurturing behavior, promoting a reparative attitude on the part of the father that could be extended and developed throughout the relational network. This entailed working with concepts such as “reconfirmation” and the “relational incubator.” The idea that the relational roots of psychopathology (which do not deny the importance of biological bases) are to be found in the obstruction of love by power is proposed as an ultramodern premise capable of integrating both modernist and postmodern concepts and sensibilities.
Automated flicker perimetry in glaucoma using Octopus 311: a comparative study with the Humphrey Matrix
Authors: Matsumoto Chota , Takada Sonoko , Okuyama Sachiko , Arimura Eiko , Hashimoto Shigeki , Shimomura Yoshikazu
Published: February 2006

Purpose:  We evaluated the clinical usefulness of flicker perimetry in glaucoma and glaucoma suspect patients using the new Octopus 311 automated perimeter.

Methods:  A total of 52 eyes of 52 glaucoma patients, 26 eyes of 26 glaucoma suspect patients and 61 eyes of 61 normal subjects were examined using standard automated perimetry (SAP), flicker perimetry and frequency doubling technology (FDT) perimetry. Flicker perimetry was performed using the Octopus 311 and its remote software package. Suprathreshold four‐zone probability strategy was used to classify the critical fusion frequency probability level. The classified levels were set at 5% and 1% of probability of normality and 5 Hz. Frequency doubling technology perimetry was performed using 24‐2‐5, 24‐2‐1, N‐30–5, N‐30–1 screening programs using Humphrey Matrix perimetry. Standard automated perimetry was performed using the Humphrey field analyser program 24–2 full threshold. Optical coherence tomography using Stratus OCT was used for evaluating the retinal nerve fibre layer thickness in all glaucoma and glaucoma suspect patients.

Results:  Receiver operating characteristic (ROC) curves were calculated. In the early stage of glaucoma, the areas under the ROC curve (AUCs) were 0.96 in flicker and 0.90 in Matrix perimetry. In the moderate and advanced stages of glaucoma, the AUCs were almost 1.0 in all tests. In glaucoma suspect patients, the AUC of the 5% probability level in flicker was significantly higher than in Matrix perimetry.

Conclusion:  The four‐zone probability strategy using the Octopus 311 is a useful method for evaluating the flicker field in early glaucoma and glaucoma suspect patients.
Human embryonic stem cells: origin, properties and applications
Authors: SEMB HENRIK
Published: February 2006

Human embryonic stem cells originate from the human preimplantation embryo. The derivation of the first human embryonic stem cells was reported in 1998. Since then we have learnt a great deal about how to isolate and culture these cells. Additionally, their stem cell phenotype and differentiation competence have been determined. Although it is expected that many basic biological properties, such as self‐renewal and cell specification, are evolutionary conserved, at least from the mouse, we lack significant knowledge about the molecular events that regulate the unique stem cell features of human embryonic stem cells. The pluripotent nature of human embryonic stem cells has attracted great interest in using them as a source of cells and tissues in cell therapy. Recent progress in human somatic cell nuclear transfer suggests that there may be a solution to the immunotolerance problems associated with the use of human embryonic stem cells in cell‐replacement therapy. Thus, human embryonic stem cells supply the research community with unique research tools to study basic biological processes in human cells, model human genetic diseases and develop new cell‐replacement therapies.
Effects of a physical exercise intervention on subjective physical well‐being, psychosocial functioning and general well‐being among office workers: A cluster randomized‐controlled cross‐over design
Authors: Sjögren T. , Nissinen K. J. , Järvenpää S. K. , Ojanen M. T. , Vanharanta H. , Mälkiä E. A.
Published: February 2006

The purpose of the study was to examine the effects of a workplace physical exercise intervention on subjective physical well‐being, psychosocial functioning and general well‐being.

The study was a cluster randomized‐controlled trial with the department (n=4) as the unit of randomization. The subjects (n=90) were office workers [mean age 45.7 (SD 8.5) years]. Psychosocial functioning and well‐being variables were measured by descriptive visual rating scales. The cross‐over design consisted of one 15‐week intervention period of light resistance training and guidance and another 15‐week period of no training and no guidance. The statistical analysis was based on linear mixed models.

The active component of the intervention, light resistance training, resulted in a slight, but statistically significant, increase in subjective physical well‐being (P=0.015). At the average training time of 5 min/working day (25 min/week) the average increase during the 15‐week period was 4 units (95% confidence interval (CI) 1–7) and 5% (95% CI 1–9). The physical exercise intervention had no effect on somatic symptoms, anxiety, self‐confidence, mood, mental stress at work, working atmosphere, life satisfaction or meaning of life.

Daily light resistance training, conducted during the working day, had a positive direction on subjective physical well‐being among office workers.
Berkeley's Half‐Way House
Authors: Hight Marc
Published: February 2006

George Berkeley's New Theory of Vision is frequently read as a simple precursor or “half‐way house” to his later metaphysics. As a result, some allege the value of the New Theory has been overlooked as critics judge it by its association with immaterialism. In this piece I examine the ongoing debate over the nature of the connection between Berkeley's early work on perception and his later immaterialist tracts. I identify four principal positions on the nature of the connection that have been advanced in the scholarly literature, critically engage the evidence for and against them, and finally weigh in by arguing that an excellent case can be made for thinking that the New Theory is a half‐way house to immaterialism after all.
‘Let's talk about sex’: balancing children's rights and parental responsibilities
Authors: Cumper Peter
Published: February 2006

Although sex education lessons have been provided in our schools for many years, concerns about the sexual health and practices of the nation's youth remain centre stage. In recent years, a number of initiatives have been introduced, with varying degrees of success, to increase young people's awareness of sexual matters and to reduce the high number of unplanned teenage pregnancies. One particularly controversial idea is that parents should be divested of the right to withdraw their children from sex education classes. In this paper, I consider the implications of this proposal, paying special attention to the response of those conservative religious organisations most likely to oppose it. My central thesis is that, while the state should be careful not to ride rough-shod over the wishes of parents in what is an extremely emotive area, the interests of the child are paramount and all young people in maintained secondary schools should have access to comprehensive sex education programmes.
Regulatory convergence?
Authors: Vick Douglas W
Published: February 2006

The Communications Act 2003 can be seen as yet another attempt to reconcile the contradictions resulting from the great schism between Market and Social Liberalism that dominated twentieth-century political discourse in the West, in this case applied to the intricacies of media regulation. In this respect, the Act is simply the latest manifestation of an on-going process of philosophical accommodation that has been characteristic of British media policy, at least since World War II, if not before. This accommodation has always been imperfect, and the debates over the Act's more controversial provisions indicate that the tensions between the competing schools of liberalism will persist well into the twenty-first century.
Monetary remedies in public law – misdiagnosis and misprescription
Authors: Bagshaw Roderick
Published: February 2006

This paper argues that the Law Commission's discussion paper Monetary Remedies in Public Law was vitiated by three flaws prevalent in the critical literature that it surveyed. The first, and most significant, flaw is a tendency to proceed by dislocating legal rules from their context then comparing them as abstract verbal formulae. This is made apparent through a comparison between unreasonableness in the tort of negligence and Wednesbury unreasonableness. The second flaw is the presentation of evaluative conclusions without a sufficient defence of the criteria used to reach them. The third flaw is the adoption of an unhelpfully static perspective as to the purpose of public-law liability rules, which neglects the positive role that they play in structuring good public decision making. The paper concludes by providing a sketch for the design of a research project which transcends these flaws.
Creep-Fatigue Life Evaluation Method for Perforated Plates at Elevated Temperature
Authors: Watanabe Osamu , Koike Takuya
Published: February 2006

The accurate evaluation scheme for creep-fatigue strength is one of the continuing main issues for elevated temperature design; particularly, the three-dimensional structure having stress concentration is becoming more important. The present paper investigates fatigue strength and creep-fatigue strength of perforated plate having stress concentration as an example. The specimens are made of type 304 SUS stainless steel, and the temperature is kept to 550°C. The whole cycles of the experiment record are analyzed, and the characteristics of the structure having stress concentration are discussed. The present paper employs stress redistribution locus (abbreviated as SRL) in evaluation plastic behavior in cyclic fatigue process as well as stress relaxation in creep process, and the feasibility is discussed in conjunction with the comparison to experimental results.
Historical Development of a Standard to Reduce Risk From Pressure Systems Failure–Part I: The ASME HPS Section 6000
Authors: Brown Samuel J.
Published: February 2006

The ASME HPS Standard Section 6000 (as well as Sections 1000 to 5000) was begun with a draft outline in 1981 and released in 2003. Section 6000 “Hazardous Release Protection” of the High Pressure Systems (HPS) standard provides a risk-based criterion to assess the pressure system internal and external kinetic energy and degenerative hazards and permits a number of ways to lower risk to personnel and structures (e.g., redesign of the pressure system (improved system performance), protection (reduction of consequences), improved inspection (reduction of event probability), etc.). Part I of this paper examines the history of the development of Section 6000, the motivating safety issues; some incidences of system failures, which identify a need for guidance regarding tolerable risk; other guidelines, standard, and code development; and some references that document its development.
A Plastic Load Criterion for Inelastic Design by Analysis
Authors: Mackenzie Donald , Li Hongjun
Published: February 2006

The allowable plastic load in pressure vessel design by analysis is determined by applying a graphical construction to a characteristic load-deformation plot of the collapse behavior of the vessel. This paper presents an alternative approach to the problem. The plastic response is characterized by considering the curvature of a plot of plastic work dissipated in the vessel against the applied load. It is proposed that salient points of curvature correspond to critical stages in the evolution of the gross plastic deformation mechanism. In the proposed plastic work curvature (PWC) criterion of plastic collapse, the plastic load is defined as the load corresponding to zero or minimal plastic work curvature after yielding and the formation of plastic mechanisms have occurred. Application of the proposed criterion is illustrated by considering the elastic-plastic response of a simple cantilever beam in bending and a complex three-dimensional finite element analysis of a nozzle intersection. The results show that the proposed approach gives higher values of plastic load than alternative criteria when the material exhibits strain hardening. It is proposed that this is because the PWC criterion more fully represents the constraining effect of material strain hardening on the spread of plastic deformation.
Determination of Corrosion Layers and Protective Coatings on Steels and Alloys Used in Simulated Service Environment of Modern Power Plants
Authors: Nickel Hubertus , Quadakkers Willem J. , Singheiser Lorenz
Published: February 2006

The development of modern power generation systems with higher thermal efficiency requires the use of constructional materials of higher strength and improved resistance to the aggressive service atmospheres. In this paper, the following examples are discussed. (i) The oxidation behavior of 9% Cr steels in simulated combustion gases: The effects of O2 and H2O content on the oxidation behavior of 9% Cr steels in the temperature range 600-800°C showed that in dry oxygen a protective scale was formed with an oxidation rate controlled by diffusion. In contrast, that in the presence of water vapor, after an incubation period, the scale became nonprotective as a result of a change in the oxidation mechanism. (ii) The development of NiCrAlY alloys for corrosion-resistant coatings and thermal barrier coatings of gas turbine components: The increase of component surface temperature in modern gas turbines leads to an enhanced oxidation attack of the blade coating. Considerable efforts have been made in the improvement of the temperature properties of MCrAlY coatings by the additions of minor elements, such as yttrium, silicon, and titanium. The experimental results show the positive, but different influence of the oxidation behavior of the MCrAlY coatings by the addition of these minor elements. (iii) The development of lightweight intermetallics of TiAl-basis: TiAl-based intermetallics are promising materials for future turbine components because of the combination of high-temperature strength and low density. These alloys, however, possess poor oxidation resistance at temperatures above 700°C. The experimental results showed that the oxidation behavior of TiAl-based intermetallics can be strongly improved by minor additions of 1-2at.% silver. (iv) The oxide-dispersion-strengthened (ODS) alloys provide excellent creep resistance up to much higher temperatures than can be achieved with conventional wrought or cast alloys in combination with suitable high-temperature oxidation/corrosion resistance. The growth mechanisms of protective chromia and alumina scales were examined by a two-stage oxidation method with O18 tracer. The distribution of the oxygen isotopes in the oxide scale was determined by secondary ion-mass spectroscopy and SNMS. The results show the positive influence of a Y2O3 dispersion on the oxidation resistance of the ODS alloys and its effect on growth mechanisms.
Fatigue Analysis in Pressure Vessel Design by Local Strain Approach: Methods and Software Requirements
Authors: Kalnins Arturs
Published: February 2006

The purpose, methods for the analysis, software requirements, and meaning of the results of the local strain approach are discussed for fatigue evaluation of a pressure vessel or its component designed for cyclic service. Three methods that are consistent with the approach are evaluated: the cycle-by-cycle method and two half-cycle methods, twice-yield and Seeger’s. For the cycle-by-cycle method, the linear kinematic hardening model is identified as the cyclic plasticity model that produces results consistent with the local strain approach. A total equivalent strain range, which is entered on a material strain-life curve to read cycles, is defined for multiaxial stress situations
Japanese Activities Concerning Nuclear Codes and Standards—Part II
Authors: Asada Yasuhide
Published: February 2006

This series of papers has been issued to give general views on recent Japanese activities related to nuclear codes and standards. Part II of the series describes component aging aspects and future trends. The component aging aspects include evaluation methods for vessels based on elastic-plastic fracture mechanics, environmental fatigue evaluation guidelines and inspection and evaluation guidelines for reactor internals. With respect to future trends, the development of the International Thermonuclear Experimental Reactor code and the System-Based Code are introduced.
Historical Development of a Standard to Reduce Risk From Pressure Systems Failure— Part II: The ASME HPS-2003 Section 6000 “Hazardous Release Protection”
Authors: Brown Samuel J.
Published: February 2006

The ASME High Pressure System (HPS) Standard Section 6000 (as well as Sections 1000–5000) was begun with a draft outline in 1981 and released in 2003. Section 6000 “Hazardous Release Protection” of the HPS standard provides a risk-based criterion to assess the pressure system internal and external kinetic energy and degenerative hazards and permits a number of ways to lower risk to personnel and structures (e.g., redesign of the pressure system (improve system performance), protection, (reduction of consequences), improved inspection (reduction of event probability), etc.). This Part II paper examines the scope and intent of the various paragraphs of the ASME Section 6000 of the HPS standard, its relationship to Sections 1000–5000 of the HPS, and some incidences of system failures that identify a need for guidance regarding tolerable risk, and some references that document its development.
New Piping Flexibility Rules in ASME B31.3, Appendix P
Authors: Becht Charles , Diehl David W.
Published: February 2006

Alternative rules for performing flexibility analysis were added, as Appendix P, in ASME B31.3, the Process Piping Code, 2004 edition. These rules are considered to be more comprehensive than before; they were designed around computer flexibility analysis. To determine stress range, the difference in stress states, considering all loads, is computed. This paper describes the new rules, their intent, and provides several example piping stress analyses, comparing the results of an analysis using the Appendix P rules with that using the rules in the base Code.
ASME Section III Design-By-Analysis Criteria Concepts and Stress Limits
Authors: Slagis Gerry C.
Published: February 2006

The ASME Section III design-by-analysis approach provides stress criteria for the design of nuclear components. Stresses are calculated elastically for the most part, although plastic analysis is recognized. Limits are specified for primary, secondary, and peak stresses. Inherent in these limits are factors of safety against several modes of failure. The purpose of this paper is to explain the design-by-analysis criteria and fundamental concepts behind the approach. Topics covered include the bases for the primary stress limits, shakedown to elastic action, fatigue, simplified elastic-plastic analysis, and thermal stress ratchet. Issues that are explored are separating primary and secondary stresses in finite element analyses, material ductility requirements, and the meaning of the fatigue penalty factor.
New Development in Studies on the Characteristics of Bolted Pipe Flange Connections in JPVRC
Authors: Sawa Toshiyuki , Nagata Satoshi , Tsuji Hirokazu
Published: February 2006

This paper deals with some studies carried out in the bolted flanged connection committee (BFC) in Japan Pressure Vessel Council (JPVRC) on the stress analysis of a pipe flange connection using the elastoplastic finite element method. The characteristics of the connections with the different nominal diameters from 2in. to 20in. such as the contact gasket stress distribution, the hub stress, and the load factors were examined. The results from the finite element analyses were fairly consistent with the experimental results concerning the variation in the axial bolt force. By using the contact stress distributions and the results of the leakage test, the new gasket constants were evaluated. As a result, it was found that the variations in the contact stress distributions were substantial due to the flange rotation in the pipe flange connections with the larger nominal diameter. A method to determine the bolt preload for a given tightness parameter was demonstrated and the difference in the bolt preload between our research and PVRC was shown. In addition, the characteristics of pipe flange connection under a bending moment and internal pressure were also discussed and a newly developed bolt tightening method was demonstrated.
Flexibility Factors for Branch Pipe Connections Subjected to In-Plane and Out-of-Plane Moments
Authors: Xue Liping , Widera G. E. O. , Sang Zhifu
Published: February 2006

Stress intensity factor and flexibility factor are important analysis parameters for branch pipe connections subjected to in-plane and out-of-plane moments. The calculation of stress intensity factors for a large range of unreinforced fabricated tees (0.333⩽d∕D⩽1, 20⩽D∕T⩽250, d∕D⩽t∕T⩽3) was performed by Widera and Wei [WRC Bulletin 497 2004] and empirical formulas were provided based upon a parametric finite element analysis employing four-node shell elements. The purpose of this paper is to extend the previous effort by Widera and Wei and calculate the in-plane and out-of-plane flexibility factors for the same range of geometric parameters. Similarly, empirical formulas for the determination of these flexibility factors are proposed. The results show that the lengths of the branch and run pipes as well as the geometric parameters (d∕D, D∕T and t∕T) have an effect on the calculation of flexibility factors.
Fire Versus Non-Fire Contingencies: A Study of Pressure-Relief Device Sizing Risks
Authors: Short W. E.
Published: February 2006

There are tens of thousands of industrial manufacturing facilities operating throughout the world. Each chemical plant, petroleum refinery, pharmaceutical plant and other manufacturing facility has equipment and piping systems that operate under pressure. In the event of excessive overpressure, equipment or piping failures could result in economic loss to business, environmental contamination, and health and safety risks. To reduce such risks, equipment and piping systems that operate under pressure must be protected from excessive overpressure. This is accomplished with the installation of pressure-relief devices, which must be properly sized and specified for the intended service conditions. More specifically, overpressure protection is provided by pressure-relief devices that are sized, selected, specified and installed for the postulated governing overpressure contingency. To adequately size a pressure-relief device to provide overpressure protection for equipment and piping, several relief event scenarios always should be considered. In the U.S.A., federal and state regulations require operating industrial facilities to have risk management programs in place that include the design basis for safety-relief systems installed to protect pressurized equipment from overpressure. For new installations, the pressure-relief system design philosophy should be established during the project design phase. However, for process facilities that have been in operation for many years, the original design basis and calculations for the safety-relief devices often are no longer available. For existing pressure-relieving installations, fitness-for-service assessments should include verification of the relief device size and specification, and review and substantiation of required documentation. This paper presents results from a study intended to examine which overpressure relief contingency, if any, most often governs the size of relief devices that are used to protect equipment and piping systems. The required elements of a pressure-relieving system sizing and documentation program are described. The author emphasizes seven relief contingencies to be considered when sizing pressure-relief devices. Some restrictions and limitations of the codes and standards that are applied for design guidance of pressure-relieving systems are challenged. For this study, relief device sizing data was compiled from a number of chemical and petrochemical project applications to provide a reasonable sample of contingencies that governed the sizes of existing and new safety-relief valves and rupture disks. The study results show that a significant number of pressure-relief devices presently installed in the U.S.A. likely are undersized. This further suggests that, worldwide, an alarming number of pressure-relief devices may be undersized.
Effect of Loading on Stress Intensification Factors
Authors: Scavuzzo Rudolph J.
Published: February 2006

The basic objective of this investigation is to determine the effect of loading on the stress intensification factors of Markl’s fatigue evaluation method for metal piping. Markl’s method is based on the fatigue testing of 4 in. schedule 40 carbon steel cantilever piping. Subsequent testing using a four-point loading showed that the S-N data were different from that predicted by the procedure and equation developed by Markl. Markl’s method is based on determining the elastic-plastic forces in a piping system by multiplying the elastic system stiffness by the actual deflection. In this manner a fictitious force is calculated to determine piping stresses assuming the elastic beam bending equation, Mc/I, applies even in partially plastic pipes. Previous analytical work on this topic by Rodabaugh and Scavuzzo (“Fatigue of Butt Welded Pipe and the Effect of Testing Methods–Report 2: Effect of Testing Methods on Stress Intensification Factors,” Welding Research Bulletin 433, July 1998) showed that these measured differences should occur between cantilever and four-point tests using Markl’s method. The basic assumption in this analytical comparison is that strain-cycle correlations lead to the correct prediction of fatigue life. Using the measured alternating strain, both types of test geometries lead to the same prediction of fatigue life using these strain-cycle correlations. In this study, the same analytical assumptions used by Rodabaugh and Scavuzzo (above) are applied to a pipe where the load is varied from a four-point loading through its extremes. Loads were varied from a cantilever to an end moment by changing the dimensions of four-point loading. Also, the shape of a bilinear stress-strain curve was varied from a perfectly plastic material to various degrees of work hardening by increasing the tangent modulus in the plastic regime. The results of the study indicate that Markl’s method is conservative by predicting too short a fatigue life for four-point loading for a given stress. As indicated by this study, the differences can be very large in the low-cycle regime for a perfectly plastic material and for a four-point loading approaching an end moment. Thus, piping could be over designed with unnecessary conservatism using the current ASME Code method based on stress intensification factors.
Uncertainty in Finite Element Modeling and Failure Analysis: A Metrology-Based Approach
Authors: Fong Jeffrey T. , Filliben James J. , deWit Roland , Fields Richard J. , Bernstein Barry , Marcal Pedro V.
Published: February 2006

In this paper, we first review the impact of the powerful finite element method (FEM) in structural engineering, and then address the shortcomings of FEM as a tool for risk-based decision making and incomplete-data-based failure analysis. To illustrate the main shortcoming of FEM, i.e., the computational results are point estimates based on “deterministic” models with equations containing mean values of material properties and prescribed loadings, we present the FEM solutions of two classical problems as reference benchmarks: (RB-101) The bending of a thin elastic cantilever beam due to a point load at its free end and (RB-301) the bending of a uniformly loaded square, thin, and elastic plate resting on a grillage consisting of 44 columns of ultimate strengths estimated from 5 tests. Using known solutions of those two classical problems in the literature, we first estimate the absolute errors of the results of four commercially available FEM codes (ABAQUS, ANSYS, LSDYNA, and MPAVE) by comparing the known with the FEM results of two specific parameters, namely, (a) the maximum displacement and (b) the peak stress in a coarse-meshed geometry. We then vary the mesh size and element type for each code to obtain grid convergence and to answer two questions on FEM and failure analysis in general: (Q-1) Given the results of two or more FEM solutions, how do we express uncertainty for each solution and the combined? (Q-2) Given a complex structure with a small number of tests on material properties, how do we simulate a failure scenario and predict time to collapse with confidence bounds? To answer the first question, we propose an easy-to-implement metrology-based approach, where each FEM simulation in a grid-convergence sequence is considered a “numerical experiment,” and a quantitative uncertainty is calculated for each sequence of grid convergence. To answer the second question, we propose a progressively weakening model based on a small number (e.g., 5) of tests on ultimate strength such that the failure of the weakest column of the grillage causes a load redistribution and collapse occurs only when the load redistribution leads to instability. This model satisfies the requirement of a metrology-based approach, where the time to failure is given a quantitative expression of uncertainty. We conclude that in today’s computing environment and with a precomputational “design of numerical experiments,” it is feasible to “quantify” uncertainty in FEM modeling and progressive failure analysis.
A theorem about the angular momentum and magnetic energy of stationary, axial field distributions
Authors: Gauthier N.
Published: February 2006

The angular momentum of a steady, axially symmetric distribution of electromagnetic fields is shown to be expressible as Lem=∫dQr×A, where dQ is an element of moving charge at position r and A is the local vector potential. This result, which is valid for relativistic motion, gives an easy way of calculating the angular momentum of symmetric distributions of charges or currents. A consequence of this result is that in the nonrelativistic limit, the magnetic energy of the distribution can be expressed solely in terms of the angular momentum Lem and the angular velocity of the rotating system, k̂ω, as Umag=12(k̂ω)∙Lem. This result is applied to three uniform, nonrelativistic, spinning charge distributions: a cylindrical shell, a spherical shell, and a solid sphere.
Plant Volatile Compounds: Sensory Cues for Health and Nutritional Value?
Authors: Goff Stephen A. , Klee Harry J.
Published: February 2006

Plants produce many volatile metabolites. A small subset of these compounds is sensed by animals and humans, and the volatile profiles are defining elements of the distinct flavors of individual foods. Flavor volatiles are derived from an array of nutrients, including amino acids, fatty acids, and carotenoids. In tomato, almost all of the important flavor-related volatiles are derived from essential nutrients. The predominance of volatiles derived from essential nutrients and health-promoting compounds suggests that these volatiles provide important information about the nutritional makeup of foods. Evidence supporting a relation between volatile perception and nutrient or health value will be reviewed.
Gene Regulatory Networks and the Evolution of Animal Body Plans
Authors: Davidson Eric H. , Erwin Douglas H.
Published: February 2006

Development of the animal body plan is controlled by large gene regulatory networks (GRNs), and hence evolution of body plans must depend upon change in the architecture of developmental GRNs. However, these networks are composed of diverse components that evolve at different rates and in different ways. Because of the hierarchical organization of developmental GRNs, some kinds of change affect terminal properties of the body plan such as occur in speciation, whereas others affect major aspects of body plan morphology. A notable feature of the paleontological record of animal evolution is the establishment by the Early “Cambrian of virtually all phylum-level body plans. We identify a class of GRN component, the kernels” of the network, which, because of their developmental role and their particular internal structure, are most impervious to change. Conservation of phyletic body plans may have been due to the retention since pre-Cambrian time of GRN kernels, which underlie development of major body parts.
Caspases 3 and 7: Key Mediators of Mitochondrial Events of Apoptosis
Authors: Lakhani Saquib A. , Masud Ali , Kuida Keisuke , Porter George A. , Booth Carmen J. , Mehal Wajahat Z. , Inayat Irteza , Flavell Richard A.
Published: February 2006

The current model of apoptosis holds that upstream signals lead to activation of downstream effector caspases. We generated mice deficient in the two effectors, caspase 3 and caspase 7, which died immediately after birth with defects in cardiac development. Fibroblasts lacking both enzymes were highly resistant to both mitochondrial and death receptor–mediated apoptosis, displayed preservation of mitochondrial membrane potential, and had defective nuclear translocation of apoptosis-inducing factor (AIF). Furthermore, the early apoptotic events of Bax translocation and cytochrome c release were also delayed. We conclude that caspases 3 and 7 are critical mediators of mitochondrial events of apoptosis.
Volatile Signaling in Plant-Plant Interactions: "Talking Trees" in the Genomics Era
Authors: Baldwin Ian T. , Halitschke Rayko , Paschold Anja , von Dahl Caroline C. , Preston Catherine A.
Published: February 2006

Plants may “eavesdrop” on volatile organic compounds (VOCs) released by herbivore-attacked neighbors to activate defenses before being attacked themselves. Transcriptome and signal cascade analyses of VOC-exposed plants suggest that plants eavesdrop to prime direct and indirect defenses and to hone competitive abilities. Advances in research on VOC biosynthesis and perception have facilitated the production of plants that are genetically “deaf” to particular VOCs or “mute” in elements of their volatile vocabulary. Such plants, together with advances in VOC analytical instrumentation, will allow researchers to determine whether fluency enhances the fitness of plants in natural communities.
The Molecular Basis for Wine Grape Quality-A Volatile Subject
Authors: Lund Steven T. , Bohlmann Joerg
Published: February 2006

Volatile organic compounds are important flavor components of finished wines. In addition to winemaking practices, which shape wine quality, cultivation of the grape berries in the vineyard each season affects the production of volatile organic compounds as well as other chemical components that ultimately contribute to our perception of flavor in finished wines. By studying how berry flavor components are determined by the interplay of vine genotypes, the environment, and cultivation practices at the molecular level, scientists will develop advanced tools and knowledge that will aid viticulturalists in consistently producing balanced, flavorful berries for wine production.
Flowers and Fungi Use Scents to Mimic Each Other
Authors: Kaiser Roman
Published: February 2006

Some flowering plants mimic the scent and appearance of mushroom fruiting bodies. Fungi may also mimic flowers. In addition, infection of plants by certain fungi can direct the plant to develop nonfunctional floral-like structures that nonetheless primarily serve the reproductive advantage of the fungus. These various mimicries may serve to attract insects that in turn spread fungal spores or plant pollen, thus facilitating sexual reproduction of the cryptic organism.
Comment on "Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth" I
Authors: Glikson Andrew
Published: February 2006

Watson and Harrison (Reports, 6 May 2005, p. 841) proposed a model for early Earth magmatism based on crystallization temperatures of Hadean zircons. However, detrital zircon populations are skewed relative to the composition of their source terrains, Archaean isotopic and geochemical mantle signatures preclude reincorporation of Hadean continental crust into the early mantle, and the effects of early impacts should be considered.
The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years
Authors: Osborn Timothy J. , Briffa Keith R.
Published: February 2006

Periods of widespread warmth or cold are identified by positive or negative deviations that are synchronous across a number of temperature-sensitive proxy records drawn from the Northern Hemisphere. The most significant and longest duration feature during the last 1200 years is the geographical extent of warmth in the middle to late 20th century. Positive anomalies during 890 to 1170 and negative anomalies during 1580 to 1850 are consistent with the concepts of a Medieval Warm Period and a Little Ice Age, but comparison with instrumental temperatures shows the spatial extent of recent warmth to be of greater significance than that during the medieval period.
The Nucleosomal Surface as a Docking Station for Kaposi's Sarcoma Herpesvirus LANA
Authors: Barbera Andrew J. , Chodaparambil Jayanth V. , Kelley-Clarke Brenna , Joukov Vladimir , Walter Johannes C. , Luger Karolin , Kaye Kenneth M.
Published: February 2006

Kaposi's sarcoma–associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) mediates viral genome attachment to mitotic chromosomes. We find that N-terminal LANA docks onto chromosomes by binding nucleosomes through the folded region of histones H2A-H2B. The same LANA residues were required for both H2A-H2B binding and chromosome association. Further, LANA did not bind
Xenopus
sperm chromatin, which is deficient in H2A-H2B; chromatin binding was rescued after assembly of nucleosomes containing H2A-H2B. We also describe the 2.9-angstrom crystal structure of a nucleosome complexed with the first 23 LANA amino acids. The LANA peptide forms a hairpin that interacts exclusively with an acidic H2A-H2B region that is implicated in the formation of higher order chromatin structure. Our findings present a paradigm for how nucleosomes may serve as binding platforms for viral and cellular proteins and reveal a previously unknown mechanism for KSHV latency.
Essential Role of BDNF in the Mesolimbic Dopamine Pathway in Social Defeat Stress
Authors: Berton Olivier , McClung Colleen A. , DiLeone Ralph J. , Krishnan Vaishnav , Renthal William , Russo Scott J. , Graham Danielle , Tsankova Nadia M. , Bolanos Carlos A. , Rios Maribel , Monteggia Lisa M. , Self David W. , Nestler Eric J.
Published: February 2006

Mice experiencing repeated aggression develop a long-lasting aversion to social contact, which can be normalized by chronic, but not acute, administration of antidepressant. Using viral-mediated, mesolimbic dopamine pathway–specific knockdown of brain-derived neurotrophic factor (BDNF), we showed that BDNF is required for the development of this experience-dependent social aversion. Gene profiling in the nucleus accumbens indicates that local knockdown of BDNF obliterates most of the effects of repeated aggression on gene expression within this circuit, with similar effects being produced by chronic treatment with antidepressant. These results establish an essential role for BDNF in mediating long-term neural and behavioral plasticity in response to aversive social experiences.
Experimental Study of Inequality and Unpredictability in an Artificial Cultural Market
Authors: Salganik Matthew J. , Dodds Peter Sheridan , Watts Duncan J.
Published: February 2006

Hit songs, books, and movies are many times more successful than average, suggesting that “the best” alternatives are qualitatively different from “the rest”; yet experts routinely fail to predict which products will succeed. We investigated this paradox experimentally, by creating an artificial “music market” in which 14,341 participants downloaded previously unknown songs either with or without knowledge of previous participants' choices. Increasing the strength of social influence increased both inequality and unpredictability of success. Success was also only partly determined by quality: The best songs rarely did poorly, and the worst rarely did well, but any other result was possible.
Response to Comments on "Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth"
Authors: Watson E. B. , Harrison T. M.
Published: February 2006

The mean crystallization temperature of Hadean zircons estimated on the basis of titanium content is ∼680°C. This value corresponds almost uniquely to the temperature of wet minimum melting in present-day crust. The low variance of the temperature distribution (±25°C) also points unequivocally to Hadean zircon growth under conditions that were highly reproducible and thermally regulated. Eutectic-like melting is particularly capable of providing such regulation and is consistent with Hadean zircon growth during wet crustal fusion.