bluuebunny/crossref_metadata_2025 huggingface dataset:
Advocacy and administration: from conflict to collaboration
Authors: Zaretsky Lindy
Published: April 2004

Reports the findings of a qualitative study investigating the interactions relating to special education between principals and parent advocates. Specifically focuses on variations in perspectives among the principals and parent advocates on disability, special education and inclusion. Places a particular emphasis on exploring the perceived power imbalances in decision‐making processes and in incompatibility or conflict among values and interests. Data collected through a series of individual interviews and group dialogues involving both advocates and administrators, reveal how the participants define and manage their respective professional roles as they engage with one another in resolving ethical dilemmas in special education. The findings provide rich illustrations of shared decision‐making processes, alternative knowledge and understandings of special education and disability, and more politicized forms of parent involvement. These dialogical interactions also reveal the inequities, power imbalances and politics within organizational arenas that promote conflict. Proposes democratic, critical, and collaborative approaches to interactions as appropriate processes for managing such conflict.
Deconstructing information packages
Authors: Kallinikos Jannis
Published: April 2004

Argues that the organizational involvement of large scale information technology packages, such as those known as enterprise resource planning (ERP), has important implications that go far beyond the acknowledged effects of keeping the organizational operations accountable and integrated across functions and production sites. Claims that ERP packages are predicated on an understanding of human agency as a procedural affair and of organizations as an extended series of functional or cross‐functional transactions. Accordingly, the massive introduction of ERP packages to organizations is bound to have serious implications that precisely recount the procedural forms by which such packages instrument organizational operations and fashion organizational roles. The conception of human agency and organizational operations in procedural terms may seem reasonable yet it recounts a very specific and, in a sense, limited understanding of humans and organizations. The distinctive status of framing human agency and organizations in procedural terms becomes evident in its juxtaposition with other forms of human action like improvisation, exploration or playing. These latter forms of human involvement stand out against the serial fragmentation underlying procedural action. They imply acting on the world on loose premises that trade off a variety of forms of knowledge and courses of action in attempts to explore and discover alternative ways of coping with reality.
An experimental comparison of secret‐based user authentication technologies
Authors: Irakleous I. , Furnell S.M. , Dowland P.S. , Papadaki M.
Published: April 2004

The paper presents a comparative study of software‐based user authentication techniques, contrasting the use of traditional password and personal identifier numbers (PIN) against alternative methods involving question and answer responses and graphical representation. All methods share the common basis of some secret knowledge and rely upon the user’s ability to recall it in order to achieve authentication. An experimental trial is described, along with the results based upon 27 participants. The alternative methods are assessed in terms of practical effectiveness (in this context relating to the participant’s ability to authenticate themselves a significant time after initial use of the methods), as well as the perceived levels of user friendliness and security that they provide. The investigation concludes that while passwords and PIN approaches garner good ratings on the basis of their existing familiarity to the participants, other methods based upon image recall and cognitive questions also achieved sufficiently positive results to suggest them as viable alternatives in certain contexts.
Applying interactional psychology to salesforce management: a socialization illustration
Authors: Todd Donavan D. , Fang Xiang , Bendapudi Neeli , Singh Surendra N.
Published: April 2004

Modern interactionism asserts that both the P (person) and the E (environment or situation) should be considered simultaneously in predicting attitudes and behaviors. In this paper, we apply the interactionist view to salesforce research. Specifically, we use salesforce socialization as an example to illustrate how interactionist concepts from psychology can be effectively applied in salesforce research. The role of qualitative research in this context is explored.
Agents of change: how young consumers are changing the world of marketing
Authors: Spero Ian , Stone Merlin
Published: April 2004

This paper looks at young adults' relationship with digital media. From a commercial perspective the opportunity to deploy these channels to promote consumer recruitment and loyalty is very significant indeed. However, consumer marketing companies will have to learn to meet the needs of this very discerning and highly cynical audience by combining the best creative ideas and strategies with a transformed approach to marketing sales and service, embodying the best of information and communications technology, reliably and securely implemented. Communication networks underpin this report. While teens complain that they have less public space to hang out in, they are making the online world their milieu, their domain where they develop personal relationships and where they play and learn new things. The conclusions cover not only the effect of current market drivers, but also emerging trends that will allow brands to better understand the behaviour of young adults, so as to establish more truthful binds with them.
N‐channel power MOSFET for fast neutron detection
Authors: Salame C. , Mialhe P. , Charles J.‐P. , Khoury A.
Published: April 2004

Developments in neutron detection technology during the past three years are reviewed with special emphasis on application to safety, security, or industrial development.An investigation about the possibility of using N‐channel power MOSFET (metal oxide semiconductor field effect transistor) as a high‐energy neutron sensitive detector is presented here. An empirical expression for neutron fluence detection is derived from the relation between neutron fluence and the evolution of the transistor current measured in the saturation region. This expression is valid for neutron fluence in the range 5×109–1×1014 n cm−2.
The investigation of the capillary flow of underfill materials
Authors: Huang C.Y.
Published: April 2004

The underfilling of flip chip components with the encapsulant is based on the principles of capillary flow. A reasonable understanding of capillary flow and an effective estimate of the encapsulant's flow time will help develop a robust process. Factors which may influence the encapsulant's flow rate and its variation include the material type (viscosity, wetting characteristics, silicon particle size, etc.), the aging of the material, the substrate preheat temperature, the chemical composition and texture of the flow surface, standoff height, and the presence of obstructions (solder bumps).A screening experiment through the use of orthogonal array was conducted to determine the factors which would have a significant effect on the encapsulant's flow rate. The screening experiments served as a precursor to subsequent process modeling and the identification of a robust process design. Comprehensive experiments were then performed to further investigate the flow behavior of the underfill materials with realistic properties.
The reliability assessment of flip chip components
Authors: Huang C.Y.
Published: April 2004

Flip chip technology involves the attachment of active side of the silicon chip onto printed circuit board or substrate. The interconnections are provided by solder bumps, which are arranged in the area under the chip. Encapsulation helps reduce the impact of the thermal stress that results from the mismatch in the coefficient of thermal expansion between the silicon chip and the substrate. The adhesion of the encapsulant to the chip and the board coating are essential to the reliability of the package. This paper studies the adhesion characteristics of an encapsulant to a flip chip package. The quality of the encapsulation was inspected using a scanning acoustic microscope. The electrical continuity of the assemblies was tested during the liquid‐to‐liquid thermal shock testing. The various delamination mechanisms were then studied. Delamination was found predominantly at the interface between the passivation layer and the encapsulant material. Comparisons were made between samples assembled by different materials used, such as chip passivation layer, encapsulant materials, and fluxes. Finally, the best material combination was determined.
Increasing placement capacity with area based optimization and line balancing
Authors: Liukkonen Timo , Tuominen Aulis
Published: April 2004

Printed wiring board placement optimization of high‐speed placement machines in a high volume surface mount line was studied based on more careful analysis of the board layout beforehand. In this method, the target is to get the board area to be assembled as small as possible in each successive placement machine, paying the most attention on component coordinates already during preliminary line balancing phase. Optimization and line balancing principles, that had showed promising results already in the first studies when compared to globally used well‐known commercial optimization systems, were now further developed. Results presented and illustrated in this paper show remarkable, comparable, improvement in both cycle time reduction and in balance of the whole surface mount line. The main difference between this method and the advanced commercial solutions is explained in detail. Board layout, feeder arrangement, sequence of fiducial registration, and XY‐table movement were taken into deeper consideration in the method.
Characterization of copper pastes for end termination application of base metal electrode MLCCs
Authors: Akhtar Masyood , Anklekar Rupendra M.
Published: April 2004

The steep rise in the cost of palladium metal in the last decade has necessitated significant research and development efforts for using the base metal nickel electrodes in the manufacture of multilayer ceramic capacitors (MLCCs). Copper termination paste is hence a natural choice for end termination application of MLCCs using nickel electrodes, manufactured employing the base metal electrode (BME) process. The inert nitrogen atmosphere processing of the BME MLCCs has posed many challenges in the selection of organics (vehicles, binders, and additives), copper powders, and glasses for copper termination paste development. The effect of various organics and glasses on the drying as well as fired properties of different copper termination pastes is discussed. The effect of drying temperature and drying time on the fired properties of the copper termination, and the selection criteria for right composition of glass for copper termination paste are discussed. The properties of low and high firing temperature copper termination pastes are also presented.
Evaluating processes for evidence‐based health care in the National Health Service
Authors: Warburton Beverly , Black Mary
Published: April 2004

This paper explores the growing interest of Health Service researchers in evaluating processes or process evaluation and discusses the relevance of this type of evaluation to the National Health Service (NHS( in the UK. Increased focus has been given to issues of evidence‐based health care since the introduction of the NHS R&D strategy in 1991. Nevertheless, there is a need to understand complex ways of working, particularly as changes in practice rarely follow a linear pattern. The basic principles of process evaluation and its links to social science methodologies are outlined, including the importance of context and the role of stakeholders, and how process evaluation can assist health professionals in their work is explored. It is then shown how the process evaluations linked to four initiatives designed to promote evidence‐based decision making or change clinicians’ behaviour were crucial for understanding the reasons for the outcomes of the initiatives.
Transitions of care: the next major quality improvement challenge
Authors: Cotter J. James , Smith Wally R. , Boling Peter A.
Published: April 2004

This review and discussion outline domains and a research agenda leading to improvements in the quality of transitions of care between health‐care settings. Over the past two decades changes in health care financing have restructured the organization and delivery of health care. Health‐care plans and insurers have shifted to provision of health care in less expensive settings and growing concerns about the quality of health care have arisen – continuity may be lost, errors may occur, and patients may end up deeply dissatisfied. To improve the quality across the continuum of care, providers will need to reconceptualize from an intra‐organizational to an inter‐organizational viewpoint and will have to focus on transitions of care across settings. Services, such as case management, must effectively bridge gaps in the continuity of care. Improved measurement of outcomes, such as satisfaction with the transition, will be necessary.
The role of clinical audit in risk reduction
Authors: Cowan P. Jane
Published: April 2004

Recent criticism of some aspects of current practice within the NHS has placed the role of clinical audit increasingly under the spotlight. In a recent publication, the National Institute for Clinical Excellence states that “the time has come for everyone in the NHS to take clinical audit very seriously”. This article considers the intimate link between clinical audit and clinical governance, a philosophy that has not yet been universally adopted. It describes the key principles of risk management within the context of clinical audit, and examines the audit burden imposed on primary and secondary care by assessors, National Service Frameworks and regulatory bodies. It discusses the challenges risk managers face in adopting a systematic review of care that seeks to avoid harm to patients, while improving outcomes and care standards.
Logistic service measurement: a reference framework
Authors: Rafele Carlo
Published: April 2004

Many companies measure their logistic performances using several methods. As a consequence, various sets of indicators can be found in practice and in the literature. In particular, the same event can be measured in different ways, so that the relative performance is sometimes totally different. The purpose of this paper is to suggest a hierarchy in logistic performance measurements. A referring model for evaluating the logistic performances is also proposed in this paper, together with the definition of a reference framework for the selection of supply chain performance measurements.
Building knowledge for and about large‐scale organizational transformations
Authors: Kotnour Tim
Published: April 2004

Contributes a collaboration approach for achieving the goals of helping an organization transform itself and expanding the body of knowledge. To support these goals, the collaboration must meet four knowledge objectives: create, assimilate, disseminate, and apply knowledge about organizational change and transformations. Four operating principles help achieve these outcomes. Enacting three functions (i.e. technical assistance, training/education, and research) accomplish the desired goals and objectives. Within this collaboration, an applied research strategy is described with five dimensions: paradigm (i.e. action research and case study), timing (i.e. initial, ongoing, post), data sources (i.e. internal, external, and literature), data collection method, and research stage (i.e. pre, central, follow‐up). Reflection on the implementation of the approach with ongoing projects at the Kennedy Space Center provides a description of the researcher’s role and lessons learned.
Theory and practice in SME performance measurement systems
Authors: Hudson Mel , Smart Andi , Bourne Mike
Published: April 2004

Describes research undertaken to evaluate the appropriateness of strategic performance measurement (PM) system development processes for small‐ and medium‐sized enterprises (SMEs). An evaluation is undertaken of ten PM approaches found in the literature. To facilitate this evaluation a typology is presented which synthesises current theory. This evaluation resulted in the identification of a process, based on its congruency to the theoretical model, which is used for an empirical investigation. Empirical data from SMEs is collected and analysed using the typology. This indicates a discontinuity between current theory and the requirements of practitioners in small companies. The paper concludes with a number of recommendations to facilitate the development of appropriate PM processes for SMEs.
The new black bag: PDAs, health care and library services
Authors: Shipman Jean P. , Morton Andrew C.
Published: April 2004

Many health‐care professionals are reaching for their palm‐size computer or personal digital assistant (PDA) as their latest indispensable health‐care instrument. How can libraries, librarians and information science professionals support further adoption of this popular peripheral tool? The Tompkins‐McCaw Library for the Health Sciences, part of the Virginia Commonwealth University Libraries, has formed a health‐care PDA Special Interest Group and sponsored a listserv to provide opportunities for informal communications. In addition, other health sciences libraries have provided instructional and program development support. Highlights such activities and programs to provide an overview of how PDAs are being used by health‐care practitioners throughout the country. In addition, offers Internet home pages and articles that specifically address health‐care applications of the PDA.
The Robbins problem: computer proofs and human proofs
Authors: Kauffman Louis H.
Published: April 2004

Discusses the relationship between computer proof and human proof. These issues are discussed both in general and specifically regarding the recent solution of the Robbins problem via a proof generated by computer. The Robbins problem was a long‐standing open problem about axioms for Boolean algebra. One point of this paper is to show that the proof of the Robbins conjecture, generated by a computer, can be filled in and understood by human beings. We accomplish this aim in the present paper by presenting a notational reformulation of Boolean algebra and the Robbins problem. The notational/linguistic issue developed here is of cybernetic, linguistic and semiotic interest. It is our contention that mathematics can behave non‐trivially under change of notation. Change of notation can be as significant as change of language. In the present case the change of language afforded by an appropriate change of notation makes a mathematical domain accessible to human beings that has heretofore been only accessible to computers.
Strategic logistics management in Singapore
Authors: Sum Chee‐Chuong , Teo Chew‐Been , Ng Kwan‐Kee
Published: April 2004

In today’s highly competitive environment, many companies are going global to acquire market share and take advantage of higher production and sourcing efficiencies. A key determinant of business performance is the role of the logistics function in ensuring the smooth flow of materials, products and information throughout the company’s supply chains. To compete effectively, companies must recognize the strategic importance of the logistics function. The strategic management of logistics and supply chain practices of companies in Singapore is examined. A framework is proposed to classify companies according to the extent that logistics is used as a competitive weapon. The practices and characteristics of the various strategic groups are then examined and analyzed. The best practices of companies with strategic logistics are also identified. The use of information technology (IT) and the factors that will shape the logistics industry in the future are also explored. Being one of the first major studies on the Singapore logistics industry, generates new insights and information for logistics managers and businessmen interested in the Singapore logistics landscape.
VIEWPOINT: The myth of global strategy
Authors: Rugman Alan M.
Published: April 2004

Suggests that globalization is a myth and does not exist in terms of a single world market with free trade. States that instead business is triad‐based, with companies operating on a regional level rather than global. Concludes that due to government regulation of the service sectors, which limits free market movement, businesses need to think local and act regional and forget globalization.
Religion and Presidential Politics in Florida: A List Experiment*
Authors: Kane James G. , Craig Stephen C. , Wald Kenneth D.
Published: April 2004

Objective. Although national surveys indicate that Americans have become more accepting of the prospect of a Jewish presidential candidate, this could reflect some voters' desire to be seen as having socially correct opinions. The present study uses a survey technique known as the “list experiment” to assess public reaction to the nomination of Jewish candidates for high office.

Methods. Two telephone surveys of registered voters in Florida, each employing the list‐experiment methodology, were conducted in October 2000 and May/June 2002.

Results. We find only limited evidence of negative affect directed at either the vice presidential candidacy of Joseph Lieberman in 2000 or a hypothetical (unnamed) Jewish presidential candidate who might choose to run in the future.

Conclusions. Although there still are enough voters with anti‐Semitic views to affect the outcome of a close election, their numbers do not appear to be as great as some observers have feared.
The Context for Political Corruption: A Cross‐National Analysis*
Authors: Xin Xiaohui , Rudel Thomas K.
Published: April 2004

Objective. How do we explain variations across nations in the incidence of political corruption? Recent theoretical work locates the causes for corruption in a combination of institutional conditions: monopoly power, little accountability, and wide discretion. This focus on the form of political institutions clarifies the micro‐scale causes of political corruption, but it leaves unanswered questions about the macro‐scale causes of corruption.

Methods. This article addresses these questions about the macro scale through an analysis of perceived levels of corruption across nations.

Results. Our work identifies poverty, large populations, and small public sectors as contextual causes of corruption. Historically‐based differences in political cultures across broad geographical regions also affect the perceived incidence of corruption in nations.

Conclusion. Further research should attempt to link micro‐ and macro‐scale causes together in a single, multi‐scalar model of corruption.
Federal Defense Spending and Metropolitan and Nonmetropolitan Disparities in Economic Growth in the Southeast*
Authors: Carson Mencken F.
Published: April 2004

Objective.This study examines how defense spending in the 1980s and early 1990s affected economic growth in metropolitan and nonmetropolitan counties in the southeast.

Methods.Using county‐level Census and other government data, the study employs a spatial lag regression model to predict how defense spending interacts with manufacturing growth to affect county economic growth during the business cycles of the 1980s and early 1990s, while controlling for other measures of regional processes. I supplement the regression analysis with brief case studies of five counties in this region.

Results.The analysis shows that there is a positive interaction effect between federal defense spending and manufacturing growth on measures of income and employment growth. However, the interaction effects are much stronger and more consistent in metropolitan counties.

Conclusion.As predicted, defense spending created regional variations in economic growth across the metropolitan‐nonmetropolitan divide in the southeast during the business cycles of the 1980s and early 1990s. Moreover, documented economic growth in nonmetropolitan counties is partly a function of spatial integration with metropolitan counties. The results have implications for current trends in defense spending.
Deciding Where to Retire: Intended Retirement Location Choices of Formerly Undocumented Mexican Migrants*
Authors: Aguilera Michael Bernabé
Published: April 2004

Objective. I use transnational theory to address how transnational relationships, behavior, and context influence retirement location choices of recently legalized immigrants. I also account for the relationship between assimilation and retirement location choices.

Methods. To test these theories, I use the 1992 Legalized Population Survey to examine formerly undocumented Mexican immigrants' attachment to the United States through their intended retirement location, either the United States or Mexico. I use logistic regression to test whether the two theories are related with retirement location choices.

Results. I find strong support for the role of transnational factors, thus widening the scope of the literature to include variables linking immigrants to their communities within Mexico.

Conclusion. This study empirically tests and quantifies transnational theory using multivariate analysis, and adds to the transnational literature by suggesting that national boundaries are political constructs that do not completely contain social and economic systems.
Lies, Damned Lies, and Campaign Promises? Environmental Legislation in the 105th Congress*
Authors: Ringquist Evan J. , Dasse Carl
Published: April 2004

Objective. The extent to which candidates for elected office keep their campaign promises holds great interest for citizens and has important consequences for the quality of democracy. However, we know very little about whether candidates actually keep these promises. This article examines the relationship between campaign promises and the subsequent legislative behavior of members of Congress in the area of environmental protection.

Methods. Responses to the 1996 National Political Awareness Test (NPAT) are matched with roll‐call data on environmental issues from the 105th Congress. A series of bivariate probit models with selection are then used to assess the extent to which roll‐call votes are consistent with candidate policy statements in the NPAT.

Results. We find that members of Congress vote consistent with their campaign promises 73 percent of the time, and that NPAT responses help to predict roll‐call votes even when controlling for party, race, gender, campaign contributions, and previous environmental voting record. We also find that the propensity to keep campaign promises varies systematically across types of legislators.

Conclusions. Contrary to public perceptions, candidates for Congress routinely act to keep their campaign promises once elected, at least in the area of environmental protection policy.
Waiting to Inhale: The Demographics of Toxic Air Release Facilities in 21st‐Century California*
Authors: Pastor Manuel , Sadd James L. , Morello‐Frosch Rachel
Published: April 2004

Objectives. We examine the spatial distribution of toxic air releases and residential demographics in California using 2000 Census data and coeval information from the Federal Toxic Release Inventory for evidence of disproportionate exposure.

Methods. We use spatial analysis using GIS, and multivariate regression analysis, including ordered and multinomial logit regressions, in our study.

Results. Analytical results suggest a pattern of disproportionate exposure based on race, with the disparity most severe for Latinos, which holds in a series of multivariate regressions, including attempts to test for varying levels of pollution risk and to control for spatial dependence.

Conclusions. The study corroborates earlier research focused in the Los Angeles area, and suggests that recent concerns about environmental inequities affecting Latinos in California may be well founded.
Effects of a food supplementation experiment on reproductive investment and a post‐mating sexually selected trait in magpies Pica pica
Authors: De Neve Liesbeth , Soler Juan J. , Soler Manuel , Pérez‐Contreras Tomás , Martín‐Vivaldi Manuel , Martínez Juan G.
Published: April 2004

Food availability is an important factor affecting breeding success in birds. Food supplementation experiments in birds have in general focused on the effects on reproductive success in terms of female investment (laying date, clutch size, egg size), however, it is also known that the estimation of mate quality based on sexually selected signals influences female reproductive investment. In the particular case of magpies, females use nest size, a post‐mating sexually selected signal, to assess male's likelihood to invest in reproduction, and accordingly adjust reproductive investment (clutch size). Then, the possible effects of food supplementation on female reproductive investment could be mediated by other variables related to parental quality, such as nest size in magpies. In the present study, we explore if higher food availability in a magpie territory affected both male sexually selected traits (i.e. nest size) and female reproductive investment (laying date, egg size, clutch size). We performed a food supplementation experiment in which we experimentally increased food availability in several magpie territories, keeping others as controls. In food‐supplemented territories, males built significantly larger nests and females significantly increased egg size by 4.1% compared to control females. Results suggest that the continuous provisioning of protein rich food allowed magpie females to increase egg size. However, laying date and clutch size did not differ between control and food‐supplemented magpie pairs. Food availability also affected the relationship between female reproductive investment and nest size. In control territories, females decreased their egg size in response to a larger nest, whereas a tendency for the opposite relationship was revealed in food‐supplemented territories. We discuss the possibility that magpie females adopt different strategies for reproductive investment according to food availability.
Rates and consequences of relaying in Cassin's auklets Ptychoramphus aleuticus and rhinoceros auklets Cerorhinca monocerata breeding in a seasonal environment
Authors: Mark Hipfner J. , Charleton Kristin , Eric Davies W.
Published: April 2004

We removed first eggs from early‐laying females to measure rates and consequences of relaying in Cassin's auklets Ptychoramphus aleuticus and rhinoceros auklets Cerorhinca monocerata at Triangle Island, British Columbia, Canada. Based on egg size and composition, the investment that Cassin's auklets made in first eggs was very close to that predicted from adult body mass, whereas rhinoceros auklets invested more. In both species, a high percentage of females relaid (90% of Cassin's and 87% of rhinoceros auklets). Breeding success declined weakly with later laying among control Cassin's auklet pairs, but pairs that we induced to relay bred more successfully than naturally late pairs, and similar to values predicted from laying dates of their first eggs. Their chicks also fledged heavier and younger than late control chicks, and similar to values in early control chicks, but followed the population‐wide seasonal decline in wing length at fledging. Nestling diets were dominated by Neocalanus copepods until late in the season, a sign that feeding conditions remained favourable until late. In contrast, rhinoceros auklet pairs induced to relay followed the population‐wide seasonal decline in breeding success, which was driven by a decline in hatching success. Pacific sandlance Ammodytes hexapterus, thought to be a preferred prey species, virtually disappeared from nestling diets in mid‐to‐late season, yet there was no seasonal decline in fledging mass. However, chicks from replacement eggs followed the declines among control chicks in both age and wing length at fledging. Despite the female having produced a replacement egg, and despite delayed breeding, there appeared to be little immediate consequence associated with relaying for Cassin's auklets, except for a tendency for their chicks to fledge with short wings. Consequences were more marked in rhinoceros auklets (greatly reduced hatching success, and having their chicks fledge with short wings), and this may have been due to the large investment made in eggs, and/or to delayed breeding. Results of this study show that attributes of Cassin's and rhinoceros auklets that lay at different times in the season can be important in driving seasonal declines in breeding performance, as found in studies on other Alcidae. They also show how decisions taken during the egg stage can have variable yet potentially important implications for fitness, even in relatively long‐lived species that lay single‐egg clutches.
Systematic position of the Socorro mockingbird Mimodes graysoni
Authors: Barber Brian R. , Martínez‐Gómez Juan E. , Peterson A. Townsend
Published: April 2004

Recently acquired tissue makes possible a first molecular assessment of the taxonomic position of the Soccoro Island endemic mimid Mimodes graysoni. Mitochondrial DNA sequence data from the ND‐2 gene was analyzed using parsimony, maximum likelihood and bayesian methods of inference. These methods all placed Mimodes graysoni within a strongly supported clade containing four representatives of the genus Mimus. Retention of the monotypic Mimodes would make Mimus paraphyletic, therefore Mimodes graysoni is more properly placed in the genus Mimus.
Temporal variation in chaffinch Fringilla coelebs song: interrelations between the trill and flourish
Authors: Leitão Albertine , Van Dooren Tom J. M. , Riebel Katharina
Published: April 2004

The description of within‐population variation of a signal is an important first step when studying its communicative function. In chaffinches Fringilla coelebs all song types consist of two structurally different parts: the trill (a series of two to five phrases of repeated syllables) followed by a more complex end phrase, the so‐called flourish (a shorter sequence of mostly non‐repeated syllables). The relative durations of the two song parts have been reported to affect male and female responses in playback studies. While this suggests a communicative function of relative trill and flourish duration, within‐population variation of these parameters has not yet been quantified. We recorded 3084 songs of 108 different song types from 79 individuals and measured the song, trill and flourish duration. This revealed substantial variation in duration of the two main song parts. An analysis of the variance components showed that trill duration was more variable within song types and between birds than flourish duration, but less variable between song types. Moreover, the more different phrases there were in the trill, the longer was its duration. There was more variation in trill duration within song types with relatively short flourishes. Possible communicative functions of the observed variation are discussed in the light of previous evidence from playback experiments.
Prokaryotic and eukaryotic DNA helicases
Authors: Tuteja Narendra , Tuteja Renu
Published: April 2004

DNA helicases are ubiquitous molecular motor proteins which harness the chemical free energy of ATP hydrolysis to catalyze the unwinding of energetically stable duplex DNA, and thus play important roles in nearly all aspects of nucleic acid metabolism, including replication, repair, recombination, and transcription. They break the hydrogen bonds between the duplex helix and move unidirectionally along the bound strand. All helicases are also translocases and DNA‐dependent ATPases. Most contain conserved helicase motifs that act as an engine to power DNA unwinding. All DNA helicases share some common properties, including nucleic acid binding, NTP binding and hydrolysis, and unwinding of duplex DNA in the 3′ to 5′ or 5′ to 3′ direction. The minichromosome maintenance (Mcm) protein complex (Mcm4/6/7) provides a DNA‐unwinding function at the origin of replication in all eukaryotes and may act as a licensing factor for DNA replication. The RecQ family of helicases is highly conserved from bacteria to humans and is required for the maintenance of genome integrity. They have also been implicated in a variety of human genetic disorders. Since the discovery of the first DNA helicase in Escherichia coli in 1976, and the first eukaryotic one in the lily in 1978, a large number of these enzymes have been isolated from both prokaryotic and eukaryotic systems, and the number is still growing. In this review we cover the historical background of DNA helicases, helicase assays, biochemical properties, prokaryotic and eukaryotic DNA helicases including Mcm proteins and the RecQ family of helicases. The properties of most of the known DNA helicases from prokaryotic and eukaryotic systems, including viruses and bacteriophages, are summarized in tables.
Ribosomal protein L22 inhibits regulation of cellular activities by the Epstein‐Barr virus small RNA EBER‐1
Authors: Elia Androulla , Vyas Jashmin , Laing Kenneth G. , Clemens Michael J.
Published: April 2004

Epstein–Barr virus (EBV) is a potent mitogenic and antiapoptotic agent for B lymphocytes and is associated with several different types of human tumour. The abundantly expressed small viral RNA, EBER‐1, binds to the growth inhibitory and pro‐apoptotic protein kinase R (PKR) and blocks activation of the latter by double‐stranded RNA. Recent evidence has suggested that expression of EBER‐1 alone in EBV‐negative B cells promotes a tumorigenic phenotype and that this may be related to inhibition of the pro‐apoptotic effects of PKR. The ribosomal protein L22 binds to EBER‐1 in virus‐infected cells, but the significance of this has not previously been established. We report here that L22 and PKR compete for a common binding site on EBER‐1. As a result of this competition, L22 interferes with the ability of the small RNA to inhibit the activation of PKR by dsRNA. Transient expression of EBER‐1 in murine embryonic fibroblasts stimulates reporter gene expression and partially reverses the inhibitory effect of PKR. However, EBER‐1 is also stimulatory when transfected into PKR knockout cells, suggesting an additional, PKR‐independent, mode of action of the small RNA. Expression of L22 prevents both the PKR‐dependent and ‐independent effects of EBER‐1 in vivo. These results suggest that the association of L22 with EBER‐1 in EBV‐infected cells can attenuate the biological effects of the viral RNA. Such effects include both the inhibition of PKR and additional mechanism(s) by which EBER‐1 stimulates gene expression.
Identification and expression of the first nonmammalian amyloid‐β precursor‐like protein APLP2 in the amphibian Xenopus laevis
Authors: Collin Rob W. J. , van Strien Denise , Leunissen Jack A. M. , Martens Gerard J. M.
Published: April 2004

The Alzheimer's disease‐linked amyloid‐β precursor protein (APP) belongs to a superfamily of proteins, which also comprises the amyloid‐β precursor‐like proteins, APLP1 and APLP2. Whereas APP has been identified in both lower and higher vertebrates, thus far, APLP1 and 2 have been characterized only in human and rodents. Here we identify the first nonmammalian APLP2 protein in the South African claw‐toed frog Xenopus laevis. The identity between the Xenopus and mammalian APLP2 proteins is ≈ 75%, with the highest degree of conservation in a number of amino‐terminal regions, the transmembrane domain and the cytoplasmic tail. Furthermore, amino acid residues known to be phosphorylated and glycosylated in mammalian APLP2 are conserved in Xenopus. The availability of the Xenopus APLP2 protein sequence allowed a phylogenetic analysis of APP superfamily members that suggested the occurrence of APP and preAPLP lineages with their separation predating the mammalian‐amphibian split. As in mammals, Xenopus APLP2 mRNA was ubiquitously expressed and alternatively spliced forms were detected. However, the expression ratios between the mRNA forms in the various tissues examined were different between Xenopus and mammals, most prominently for the alternatively spliced forms containing the Kunitz protease inhibitor‐coding region that were less abundantly expressed than the corresponding mammalian forms. Thus, the identification of APLP2 in Xenopus has revealed evolutionarily conserved regions that may help to delineate functionally important domains, and its overall high degree of conservation suggests an important role for this APP superfamily member.
A (1→3)‐β‐d‐glucan recognition protein from the sponge Suberites domuncula
Authors: Perović‐Ottstadt Sanja , Adell Teresa , Proksch Peter , Wiens Matthias , Korzhev Michael , Gamulin Vera , Müller Isabel M. , Müller Werner E. G.
Published: April 2004

Sponges (phylum Porifera) live in a symbiotic relationship with microorganisms, primarily bacteria. Until now, molecular proof for the capacity of sponges to recognize fungi in the surrounding aqueous milieu has not been available. Here we demonstrate, for the demosponge Suberites domuncula (Porifera, Demospongiae, Hadromerida), a cell surface receptor that recognizes (1→3)‐β‐d‐glucans, e.g. curdlan or laminarin. This receptor, the (1→3)‐β‐d‐glucan‐binding protein, was identified and its cDNA analysed. The gene coding for the 45 kDa protein was found to be upregulated in tissue after incubation with carbohydrate. Simultaneously with the increased expression of this gene, two further genes showed an elevated steady state level of expression; one codes for a fibrinogen‐like protein and the other for the epidermal growth factor precursor. Expression of the (1→3)‐β‐d‐glucan‐binding protein and the fibrinogen‐like protein occurred in cells on the sponge surface, in the pinacoderm. By Western blotting, the product of the fibrinogen‐like protein gene was identified, the recombinant protein isolated, and antibodies raised to this protein. Their application revealed that a 5 kDa factor is produced, which is apparently processed from the 77 kDa epidermal growth factor precursor. Finally, we provided evidence that a tyrosine kinase pathway is initiated in response to exposure to d‐glucan; its phosphorylation activity could be blocked by aeroplysinin. In turn, the increased expression of the downstream genes was suppressed. We conclude that sponges possess a molecular mechanism for recognizing fungi via the d‐glucan carbohydrates on their surfaces.
Correlation between functional and structural changes of reduced and oxidized trout hemoglobins I and IV at different pHs
Authors: Gabbianelli Rosita , Zolese Giovanna , Bertoli Enrico , Falcioni Giancarlo
Published: April 2004

Circular dichroism (CD) spectra of two major hemoglobin components (Hb), HbI and HbIV, from Oncorhyncus mykiss (formerly Salmo irideus) trout were evaluated in the range 250–600 nm. HbI is characterized by a complete insensitivity to pH changes, while HbIV presents the Root effect. Both reduced [iron(II) or oxy] and oxidized (met) forms of the two proteins were studied at different pHs, 7.8 and 6.0, to obtain information about the pH effects on the structural features of these hemoglobins. Data obtained show that oxy and met‐HbI are almost insensitive to pH decrease, remaining in the R conformational state also at low pH. On the contrary, the pH decrease induces similar structural changes, characteristics of ligand dissociation and R→T transition, both in the reduced and in the oxidized HbIV. The structural changes, monitored by CD, are compared with the peroxidative activity of iron(II)‐Hb and met‐Hb forms and with the superoxide anion scavenger capacity of the proteins.
Anti‐ and pro‐oxidant effects of quercetin in copper‐induced low density lipoprotein oxidation
Authors: Filipe Paulo , Haigle Josiane , Silva João Nuno , Freitas João , Fernandes Afonso , Mazière Jean‐Claude , Mazière Cécile , Santus René , Morlière Patrice
Published: April 2004

We recently reported that, depending on its concentration, urate is either a pro‐ or an antioxidant in Cu2+‐induced low‐density lipoprotein (LDL) oxidation. We also previously demonstrated an antioxidant synergy between urate and some flavonoids in the Cu2+‐induced oxidation of diluted serum. As a result, the effect of the flavonoid quercetin on the Cu2+‐induced oxidation of isolated LDL has been studied either in the presence or absence of urate. We demonstrate that, like urate, quercetin alone, at low concentration, exhibits a pro‐oxidant activity. The pro‐oxidant behavior depends on the Cu2+ concentration but it is not observed at high Cu2+ concentration. When compared with urate, the switch between the pro‐ and the antioxidant activities occurs at much lower quercetin concentrations. As for urate, the pro‐oxidant character of quercetin is related to its ability to reduce Cu2+ with the formation of semioxidized quercetin and Cu+ with an expected yield larger than that obtained with urate owing to a more favorable redox potential. It is also shown that the pro‐oxidant activity of urate can be inhibited by quercetin. An electron transfer between quercetin and semioxidized urate leading to the repair of urate could account for this observation as suggested by recently published pulse radiolysis data. It is anticipated that the interactions between quercetin–Cu2+–LDL and urate, which are tightly controlled by their respective concentration, determine the balance between the pro‐ and antioxidant behaviors. Moreover, as already observed with other antioxidants, it is demonstrated that quercetin alone behaves as a pro‐oxidant towards preoxidized LDL.
The first representative of glycosylated three‐fingered toxins
Authors: Osipov Alexey V. , Astapova Maria V. , Tsetlin Victor I. , Utkin Yuri N.
Published: April 2004

There are different glycosylated proteins in snake venoms, but no glycosylated representatives of a large family of three‐fingered toxins have previously been detected. A new glycoprotein was isolated from the venom of the Thai cobra Naja kaouthia. MALDI MS of the glycoprotein contained an array of peaks in the range from ≈ 8900 to ≈ 9400 Da indicating its microheterogeneity. Carbohydrate analysis showed the presence of mannose, galactose, N‐acetylglucosamine, fucose and neuraminic acid. The N‐terminal sequence of the glycoprotein was identical to that of cytotoxin 3 (CX3) from N. kaouthia, and CD spectra of the glycoprotein and CX3 were almost the same. Cleavage of a glycan moiety by N‐glycosidase F gave a protein of molecular mass practically coinciding with that of CX3. MALDI MS of the tryptic digest of reduced glycoprotein S‐pyridylethylated at cysteine residues, contained peaks corresponding to all tryptic fragments of CX3, with the exception of fragment 24–30. The peak corresponding to this peptide appeared in the mass‐spectrum of similarly treated deglycosylated glycoprotein. These data show that the potential N‐glycosylation site at Asn29 in CX3 is utilized for glycan attachment and that the glycoprotein is glycosylated CX3. In vivo toxicity of the glycoprotein to the cricket Gryllus assimilis was twofold lower than that of CX3. The cytotoxic activity of the glycoprotein towards HL60 cells was about two orders of magnitude lower than that of CX3, but could be made equal to the CX3 cytotoxicity by deglycosylation. Thus for the first time we have isolated a glycosylated three‐fingered snake venom toxin wherein glycosylation appears to modulate its biological activity.