bluuebunny/crossref_metadata_2025 huggingface dataset:
CBM Elements VII
Authors: Young Patricia A.
Published: May 2010

This chapter continues with CBM Elements and the design factors related to the science of culture. The following design factors are covered in this chapter: Cultural anomalies, Cultural cultures, and Cultural futures. This section, the science of culture, draws from key concepts in the fields of physical science, biological science, earth science, ecology, futures research, and crosscultural studies to explore the scientific nature of humanity and the possibilities of cultural futures. The science of culture seeks to assist human beings in adapting to their environment so that living can be achieved. This scientific way of thinking cuts across the natural, cultural, social, physical, and biological. Science is one of many ways of interpreting human reality (White, 1949).
CBM Elements VII & Training
Authors: Young Patricia A.
Published: May 2010

This chapter continues with CBM Elements and the design factors related to the science of culture. The following design factors are covered in this chapter: Cultural infinities and Cultural nature. Also, the final area of CBM Training is covered in its entirety. Cultural infinites are those things without limits such as time, space, distance, dimension, speed, and numbers. They are unending entities. The term “entity” within this context means something that functions on its own. They pre-exist and pre-date human beings. Human beings have little control over cultural infinities. Time, space, distance and dimension are discussed as Cultural infinities.1 Time and space are discussed based on their practical applications with human beings. Distance is examined for its mathematical and practical properties. Two perspectives on dimension are presented the polaric dimension and spirit world. The polaric dimension is seen as a universal law to human existence. The spirit world is explored as an alternative universe.
Scalable Index and Data Management for Unstructured Peer-to-Peer Networks
Authors: Chiang Shang-Feng , Chiang Kuo , Yu Ruo-Jian , Wang Sheng-De
Published: May 2010

In order to improve the scalability and reduce the traffic of Gnutella-like unstructured peer-to-peer networks, index caching and controlled flooding mechanisms had been an important research topic in recent years. In this chapter the authors will describe and present the current state of the art about index management schemes, interest groups and data clustering for unstructured peer-to-peer networks. Index caching mechanisms are an approach to reducing the traffic of keyword querying. However, the cached indices may incur redundant replications in the whole network, leading to the less efficient use of storage and the increase of traffic. They propose a multiplayer index management scheme that actively diffuses the indices in the network and groups indices according to their request rate. The peers of the group that have indices with higher request rate will be placed in layers that receive queries earlier. Their simulation shows that the proposed approach can keep a high success query rate as well as reduce the flooding size.
Programmability and Scalability on Multi-Core Architectures
Authors: Yi Jaeyoung , Jang Yang J. , Oh Doohwan , Ro Won W.
Published: May 2010

In this chapter, we will describe today’s technological trends on building a multi-core based microprocessor and its programmability and scalability issues. Ever since multi-core processors have been commercialized, we have seen many different multi-core processors. However, the issues related to how to utilize the physical parallelism of cores for software execution have not been suitably addressed so far. Compared to implementing multiple identical cores on a single chip, separating an original sequential program into multiple running threads has been an even more challenging task. In this chapter, we introduce several different software programs which can be successfully ported on the future multi-core based processors and describe how they could benefit from the multi-core systems. Towards the end, the future trends in the multi-core systems are overviewed.
Scientific Workflow Scheduling with Time-Related QoS Evaluation
Authors: Dou Wanchun , Chen Jinjun
Published: May 2010

This chapter introduces a scheduling approach for cross-domain scientific workflow execution with timerelated QoS evaluation. Generally, scientific workflow execution often spans self-managing administrative domains to achieving global collaboration advantage. In practice, it is infeasible for a domain-specific application to disclose its process details for privacy or security reasons. Consequently, it is a challenging endeavor to coordinate scientific workflows and its distributed domain-specific applications from service invocation perspective. Therefore, in this chapter, the authors aim at proposing a collaborative scheduling approach, with time-related QoS evaluation, for navigating cross-domain collaboration. Under this collaborative scheduling approach, a private workflow fragment could maintain temporal consistency with a global scientific workflow in resource sharing and task enactments. Furthermore, an evaluation is presented to demonstrate the scheduling approach.
Cross-Layer Cooperative Beamforming for Wireless Networks
Authors: Dong Lun , Petropulu Athina P. , Poor H. Vincent
Published: May 2010

Cooperative beamforming (CB) is a signal transmission technique that enables long-range communications in an energy efficient manner. CB relies on cooperation from a set of distributed network nodes, each carrying a single transmit antenna and acting as elements of a virtual antenna array. By appropriately weighting their transmissions, the cooperating nodes form one or more beams to cooperatively transmit one or more message signals to the desired destinations. In this chapter, a cross-layer framework is presented that brings the CB ideas closer to implementation in a wireless network setting. The process of sharing among the network nodes the information to be beamed is studied and evaluated in terms of its effect on the spectral efficiency of the overall system. Optimal or suboptimal beamforming weights are designed, and queuing analysis is provided to study delay characteristics of source messages.
Applications of Majorization Theory in Space-Time Cooperative Communications
Authors: Sezgin Aydin , Jorswieck Eduard A.
Published: May 2010

This chapter discusses important aspects in cooperative communications such as power allocation and node distributions using majorization theory, spanning both theoretical foundations and practical issues. Majorization theory provides a large amount of tools and techniques which can be used in order to accelerate the pace of developments in this fascinating research area of cooperative communications. The aim of the chapter is to build good intuition and insight into this important field of cooperative communications and how majorization theory can be used in order to solve quite complex problems in a very efficient and elegant way. Although we focus on some specific applications, the tools can be also applied to other setups and processing techniques.
Data Gathering in Correlated Wireless Sensor Networks with Cooperative Transmission
Authors: Pillutla Laxminarayana S. , Krishnamurthy Vikram
Published: May 2010

This chapter considers the problem of data gathering in correlated wireless sensor networks with distributed source coding (DSC), and virtual multiple input and multiple output (MIMO) based cooperative transmission. Using the concepts of super and sub modularity on a lattice, we analytically quantify as how the optimal constellation size, and optimal number of cooperating nodes, vary with respect to the correlation coefficient. In particular, we show that the optimal constellation size is an increasing function of the correlation coefficient. For the virtual MIMO transmission case, the optimal number of cooperating nodes is a decreasing function of the correlation coefficient. We also prove that in a virtual MIMO based transmission scheme, the optimal constellation size adopted by each cooperating node is a decreasing function of number of cooperating nodes. Also it is shown that, the optimal number of cooperating nodes is a decreasing function of the constellation size adopted by each cooperating node. We also study numerically that for short distance ranges, SISO transmission achieves better energymutual information (MI) tradeoff. However, for medium and large distance ranges, the virtual MIMO transmission achieves better energy-MI tradeoff.
Adaptive Exception Management in Uncertain Environments
Authors: Golani Mati
Published: May 2010

The ability to continuously revise business practices is limited when referring to traditional approaches in business process management systems. However, it is essential to organizations aiming at reducing their costs and increasing their revenues. In turbulent environments, the requirement for rapid and continuous changes to business processes, result in less control over the executed activities. As a consequence, process designers are limited in producing solid, well-validated workflow models. This chapter, reviews common approaches to exception handling, focusing especially on adaptive exception handling and introduces a mechanism that allows a flexible ad-hoc generated exception handling using backtracking and forward stepping at a process instance level. A dynamic approach in this domain is required, and can bolster the ability of a business process management system to deal with unexpected situations and to resolve, in runtime, scenarios in which such resolution both is called for and does not violate any business process constraints.
Lightweight Workflow
Authors: Reijers Hajo A.
Published: May 2010

This chapter describes lightweight workflow as a possible approach to counter many of the issues related to the introduction and sustained use of operational workflow management systems. Aside from a description of the essential features of lightweight workflow, this chapter also provides a reflection on the application of lightweight workflow in practice. Lightweight workflow is a very relevant direction to be aware of for practitioners who consider the use of workflow technology. Researchers may find inspiration from this chapter to further the adoption of workflow management technology.
Designing Complex Organizations Computationally
Authors: Oros Carl L. , Nissen Mark E.
Published: May 2010

Business process management is recognized increasingly as a critical factor in organizational success, leaders and managers seek to cope with increasingly complex and dynamic environments, and traditional approaches to process management become increasingly inadequate due to their lack of flexibility and adaptability. Alternatively, an organizational form receiving considerable current focus is the Edge, which distributes knowledge and power to the “edges” of organizations, and which enables organizational members and units to self-organize and self-synchronize their activities. The dynamics of such self-organization and self-synchronization, however, are extremely complex, and balancing the flexibility and adaptability inherent in the Edge with sufficient control to avoid chaos is very challenging. We employ the state-of-the-art POWer environment for dynamic organizational representation and emulation to develop and experiment with models of competing organizational forms, and to inform our understanding of complex organizational design and management—thereby making an important contribution to theory, research methodology, and practice.
The Development of E-Government Capabilities
Authors: Lee Jae Yong
Published: May 2010

This chapter aims to explore the capabilities of governments in terms of e-government. A seven core e-government capabilities framework is presented as the framework for exploring and implementing in-house government capabilities needed to facilitate the development of e-government, measured by overall, business-oriented and IT-oriented capabilities and resulting performances. The seven capabilities are as follows: legitimation and relationship building as overall capabilities; IS/IT governance and business systems thinking as business-oriented capabilities; informed buying, contract facilitation and monitoring, and designing technical architecture as IT-oriented capabilities. This chapter attempts to develop an intellectual framework for practitioners and researchers to follow within the area of organizational abilities or personnel management in e-government era. On this point, this research will contribute to the readers’ formulation of IT strategies for their countries which was set up as the first objective of this book.
Patterns for Designing E-Government Programs
Authors: Ayyad Majed
Published: May 2010

Patterns are about finding solutions to recurring problems in a context. E-government, one believes, is full of recurring problems that are solved based on the local experience and then benchmarked with international solutions. One of the common and recurring problems in the context of e-government is the design of e-government programs. Throughout this chapter, the design process is analyzed in order to find possible patterns. If patterns exist for one context, then nations resolving the same problem have the opportunity to use the encapsulated knowledge and employ the others best practices. By this, nations can avoid remarkable cost and act proactively.
Antecedents and Consequences of the Risk Taking Behavior of Mobile Commerce Adoption in Lebanon
Authors: Charbaji Rima , Rebeiz Karim , Sidani Yusuf
Published: May 2010

This study was conducted to explore the attitude towards adopting m-commerce in Lebanon. The sample of respondents were asked twenty Likert’s type questions that taped five different areas: (1) Motives based on Psychographics: Life Style and Hobbies, (2) Perceived Ease of using M-commerce, (3) Adopting M-Commerce, (4) Perceived Credibility, and (5) Experience. Two statistical analysis, Chi-Square and path analysis, were used. Factor analysis and reliability tests were used to establish the validity and reliability of the measuring instrument (questionnaire). Path analysis was used in this study to decompose the relationships between the dependent variable “Respondents Attitude towards Adopting M-Commerce” and the independent variables “Motive,” “Experience,” and “Perceived Ease of Use.” The results of this study suggest that the relationship between the independent variables and the dependent variable to be further studied in further research using a larger sample. Having larger sample seems to be crucial in conducting similar studies.
Promoting Local Tourism through Local Government Web Site
Authors: Yang Jiaqin
Published: May 2010

This chapter is an attempt to investigate the current issues and development of the application of egovernment in promoting local tourism industry for small and local cities and counties throughout the United States. The primary data for this study are collected through a comprehensive Web site evaluation. The objectives of this chapter are: (1) to examine the use of online tourism promotion implemented in local city and county Web sites across the United States, (2) to identify major issues and challenges for local governments in promoting local tourism online, and (3) to discuss the managerial implications for future research. The data collected from this study show that there is an emerging need for improvement in promoting local tourism through e-government application.
Multinational Intellect
Authors: Gadman Leslie , Richardson Robert
Published: May 2010

The world of international business is experiencing transformations of such magnitude that existing business models have become either invalid of incomplete. A fundamental force behind these disruptions has been the emergence of the digital networked economy (Ridderstrale and Nordstrom 2004, Flores and Spinosa, 1998) with its supporting internet and communications technology. One significant manifestation of this economy is the emergence of business models designed to gain competitive advantage by bonding with customers, suppliers and complementors (Wilde and Hax 2001). From the multinational perspective outsourcing and off - shoring have been the most common examples of this approach, but user lead innovation models (von Hippel 2005) based on Open Source methods are rapidly emerging as the leading source of competitive advantage. Commitment has been argued to play an important role in determining the success of these relationships (Abrahamsson and Livari, 2002) suggesting that entrepreneurs must be adept at building and maintaining commitment based value networks (Allee 2004, Sveiby and Roland 2002, Savage 1996, Gadman 1996, Adams 2004). This paper considers the challenges associated with commitment in multinational value networking and finds them to be most problematic in the diffusion of innovation where increasing levels of commitment are required across national boundaries and cultures. (Mauer, Rai and Sali 2004). Current research into core commitment structures of virtual multinational communities is not been well established. By analyzing data from a range of sources the paper concludes that the success of value networks depends on the desire of participants to acquire history - making identities (Gauntlett 2002, Spinosa et al. 1997) by maintaining identity defining commitments across the network. Implications for theory and research are discussed.
The Role of ICTs and the Management of Multinational Intellectual Capital
Authors: Mohamed Mirghani S. , Mohamed Mona A.
Published: May 2010

This chapter provides a systematic multidisciplinary framework that defines the role of technology in leveraging IC across borders and between headquarters and subsidiaries. In reaching this conclusion, this chapter investigates the strategic importance of Information and Communication Technologies (ICTs) in the management of Intellectual Capital (IC) within a Multinational Company (MNC) ecosystem. The chapter addresses the transubstantiation of MNC into boundaryless Global Knowledge-Based Organization (GKB-MNC) which ultimately propagates into Learning MNC (LMNC). The latter is a suggested MNC category that sustains competitive advantage through systemic adoption of “Knowledge Iterative Supply Network (KISN)” model proposed by the authors. The chapter suggests a new multinational ICT/IC governance strategy that handles the emerging complexities associated with modern intangible resource synthesis.
Modelling Biological Processes Naturally using Systemic Computation
Authors: Le Martelot Erwan , Bentley Peter J.
Published: May 2010

Natural systems provide unique examples of computation in a form very different from contemporary computer architectures. Biology also demonstrates capabilities such as adaptation, self-repair, and self-organisation that are becoming increasingly desirable for our technology. To address these issues a computer model and architecture with natural characteristics is presented. Systemic computation is Turing Complete; it is designed to support biological algorithms such as neural networks, evolutionary algorithms and models of development, and shares the desirable capabilities of biology not found in conventional architectures. In this chapter the authors describe the first platform implementing such computation, including programming language, compiler and virtual machine. They first demonstrate that systemic computing is crash-proof and can recover from severe damage. The authors then illustrate various benefits of systemic computing through several implementations of bio-inspired algorithms: a self-adaptive genetic algorithm, a bio-inspired model of artificial neural networks, and finally we create an “artificial organism” - a program with metabolism that eats data, expels waste, clusters cells based on data inputs and emits danger signals for a potential artificial immune system. Research on systemic computation is still ongoing, but the research presented in this chapter shows that computers that process information according to this bio-inspired paradigm have many of the features of natural systems that we desire.
From the Real Ant to the Artificial Ant
Authors: Diaf Moussa , Hammouche Kamal , Siarry Patrick
Published: May 2010

Biological studies highlighting the collective behavior of ants in fulfilling various tasks by using their complex indirect communication process have constituted the starting point for many physical systems and various ant colony algorithms. Each ant colony is considered as a superorganism which operates as a unified entity made up of simple agents. These agents (ants) interact locally with one another and with their environment, particularly in finding the shortest path from the nest to food sources without any centralized control dictating the behavior of individual agents. It is this coordination mechanism that has inspired researchers to develop plenty of metaheuristic algorithms in order to find good solutions for NP-hard combinatorial optimization problems. In this chapter, the authors give a biological description of these fascinating insects and their complex indirect communication process. From this rich source of inspiration for researchers, the authors show how, through the real ant, artificial ant is modeled and applied in combinatorial optimization, data clustering, collective robotics, and image processing.
Nature-Inspired Informatics for Telecommunication Network Design
Authors: Nesmachnow Sergio , Cancela Héctor , Alba Enrique
Published: May 2010

The speedy pace of change in telecommunications and its ubiquitous presence have drastically altered the way people interact, impacting production, government, and social life. The infrastructure for providing telecommunication services must be continuously renewed, as innovative technologies emerge and drive changes by offering to bring new services to the end users. In this context, the problem of efficiently designing the underlying networks in order to satisfy different requirements while at the same time keeping the capital and operative expenditures bounded is of ever growing importance and actuality. Network design problems have many variations, depending on the characteristics of the technologies to be employed, as well as on the simplifying hypothesis that can be applied on each particular context, and on the planning horizon. Nevertheless, in most cases they are extremely complex problems, for which exact solutions cannot be found in practice. Nature-inspired optimization techniques (belonging to the metaheuristic computational methods) are important tools in these cases, as they are able to achieve good quality solutions in reasonable computational times. The objective of this chapter is to present a systematic review of nature-inspired techniques employed to solve optimization problems related to telecommunication network design. The review is aimed at providing an insight of different approaches in the area, in particular covering four main classes of applications: minimum spanning trees, reliable networks, local access network design and backbone location, and cellular and wireless network design. A large proportion of the papers deal with single objective models, but there is also a growing number of works that study multi-objective problems, which search for solutions that perform well in a number of different criteria. While genetic algorithms and other evolutionary algorithms appear most frequently, there is also significant research on other methods, such as ant colony optimization, particle swarm optimization, and other nature-inspired techniques.
A Document Reuse Tool for Communities of Practice
Authors: Boukottaya Aida , Charlier Bernadette , Paquier Micaël , Merz Loïc , Sire Stéphane , Vanoirbeek Christine
Published: May 2010

Virtual communities of practice are gaining importance as mean of sharing and exchanging knowledge. In such environments, information reuse is of major concern. In this paper, the authors outline the importance of structuring documents in order to facilitate the reuse of their content. They show how explicit structure representation facilitates the understanding of the original documents and helps considerably in automating the reuse process. The authors propose two main tools: the first performs automatic structure transformation using matching techniques and the second performs structure and instances evolution in a transparent and an automatic manner.
Supporting Communities of Practice by Advancing Knowledge Management between Hybrid Collaborative Environments
Authors: De Liddo Anna , Concilio Grazia
Published: May 2010

In this chapter the authors investigate a tool integration perspective to support knowledge management and exchange between Web-based and traditional collaborative environments. In particular they discuss the integration between a tool (CoPe_it!) supporting collaborative argumentation and learning in Webbased communities of practices and a hypermedia and sense making tool (Compendium) acting as a personal and collective knowledge management (KM) system in traditional collaborative environments. The authors describe the tools and drive a comparative analysis of the two groupware by focusing on the general applicability of the tools integration for supporting communities of practices and, more generally, collaborative works. Moreover the authors present the results of a case study in which the tools integration has been applied within a real community of practice. Finally they discuss main results of the tools integration in order to leverage communities of practice to a truly collaborative environment with no communication boundaries.
Using Graphs in Developing Educational Material
Authors: Hadzilacos Thanassis , Kalles Dimitris , Karaiskakis Dionysis , Pouliopoulou Maria
Published: May 2010

Distance learning institutions need to find a way to transplant the benefits of conventional tutoring practices into the development of digital content that is conducive to students’ learning needs. Therein lie two great challenges: promote real distance learning effectively and, at the same time, try to accommodate the ability of students to learn via collaboration. The authors have proposed the development of learner’s open-and-distance-learning (ODL) courses as both a theoretical model and an applied methodology to be one of their key priorities and describe how this concept co-evolves with Web mining and institutional infrastructures to address the needs of emergent communities of practice within their university, primarily of students and secondarily of tutors.
Using Storytelling as the Pedagogical Model for Web-Based Learning in Communities of Practice
Authors: Sharda Nalin
Published: May 2010

The purpose of this chapter is to show how storytelling can be used as an effective pedagogical model for enhancing learning in a community of practice (CoP) using Web-based tools. CoPs provide opportunities for learning by sharing knowledge and experience. Storytelling can make the knowledge and experience sharing discourses more engaging. However, crafting engaging stories remains a challenge. Movement oriented design (MOD) paradigm provides a framework for creating effective story plots using principles of good storytelling. Web-based tools are being used for enhancing interaction in CoPs, and now more responsive systems can be created by using Web 2.0 frameworks such as AJAX. Storytelling can be introduced as a mode of discourse in CoPs using existing text and multimedia authoring systems. However, by creating new Web 2.0 tools for story development using the MOD paradigm will allow almost anyone to create engaging educational stories and use these in a CoP.
Using Web-Based Technologies and Communities of Practice for Transformative Hybrid and Distance Education
Authors: Jones Nory , Khan Omar J.
Published: May 2010

This chapter explores the use of Web-based technologies incorporating communities of practice and social networks to enhance the learning experience in hybrid and distance (online) classes. Research suggests that using a variety of technologies and methods to reach people with different learning styles improves overall learning in a class delivery though different methods are more effective in traditional vs. online classes. Moreover, using new, emerging Web-based technologies, including both Web 1.0 and Web 2.0 software, further enhances the engagement and value of the learning experience in these classes. This chapter examines the methods and technologies that can be potentially used to create excellence learning environments in traditional hybrid and online classes.
Protocol Identification of Encrypted Network Streams
Authors: Gebski Matthew , Penev Alex , Wong Raymond K.
Published: May 2010

Traffic analysis is an important issue for network monitoring and security. The authors focus on identifying protocols for network traffic by analysing the size, timing and direction of network packets. By using these network stream characteristics, they propose a technique for modelling the behaviour of various tcp protocols. This model can be used for recognising protocols even when running under encrypted tunnels. This is complemented with experimental evaluation on real world network data.
An empirical study of consumer behavior in housing market in Colombo
Authors: Ariyawansa RG
Published: May 2010

This study aims to provide a scientific insight into the consumer behavior of the housing market in Sri Lanka. Consumer behavior in the housing market presents a veritable problem to be reckoned with, which might not yet been addressed scientifically. The broader objective of the study is, therefore, to add the knowledge of consumer behavior of housing market in Sri Lanka to the existing body of knowledge. Further, it is expected, especially, to identify the determinants of the consumer behavior, to rate them in terms of importance, and to compare the relative importance of the determinants among different market segments. This study disclosed a number of attributes of the market according to the potential buyers' views in relation to buying decision of a house. 35% of the respondents stated that they would like to buy built houses rather than engage in construction. Further, it was identified that "location" of a house is the most important determinant of the buying decision. However, it is not the dominant factor because some other factors such as "quality of construction", "price", "legality", "facilities", "neighborhood" are also more important closely as important as the location. The other revealed fact is that the demographic variables such as age, income levels, and occupation are not highly effective criteria for the segmentation of the housing market. Accordingly, it is certain that this study provides a valuable supplementary to the existing literature of the marketing management through imparting the knowledge of the consumer behavior of the housing market in Sri Lanka. DOI: 10.4038/besl.v8i1.1906 Built-Environment Sri Lanka Vol.8(1) 2008 11-19
TLR9-Dependent Induction of Intestinal α-Defensins by Toxoplasma gondii
Authors: Foureau David M. , Mielcarz Daniel W. , Menard Laurence C. , Schulthess Julie , Werts Catherine , Vasseur Virginie , Ryffel Bernhard , Kasper Lloyd H. , Buzoni-Gatel Dominique
Published: May 2010

α-Defensins (or Cryptdins [Crps]) are a group of antimicrobial peptides produced as a component of Paneth cell (PC) secretory granules in the small intestine. In vivo ligation of TLR9 by synthetic agonists leads to PC degranulation, although the mechanism by which this occurs remains uncertain. In this report, we investigated TLR9-dependent mechanisms, triggered by the parasite Toxoplasma gondii, inducing Crp release in the lumen. Oral challenge of C57BL/6J (B6) wild-type (WT) mice with T. gondii induced TLR9 mRNA upregulation associated with a marked increase of type I IFN mRNA expression. PC secretory granules were released, and Crp-3/-5 mRNA expression by purified epithelial cells was increased following oral challenge of B6 WT mice. Although PCs failed to degranulate in infected B6 TLR9−/− mice, i.p. injection of mouse IFN-β alone led to Crp-3/-5 mRNA upregulation in B6 WT and TLR9−/− mice. In addition, modulation of Crp mRNA expression in response to T. gondii infection was abrogated in B6 IFNAR−/− mice, which lack a functional type I IFN receptor. Taken together, these data demonstrate that T. gondii induces Crp-3/-5 production and release by PCs via a TLR9-dependent production of type I IFNs. Crps have a limited direct effect against T. gondii but may indirectly affect the early control of T. gondii invasiveness by promoting the initiation of a protective Th1 response against the parasite.
NK Cell Regulation of CD4 T Cell-Mediated Graft-versus-Host Disease
Authors: Rivas Magali Noval , Hazzan Marc , Weatherly Kathleen , Gaudray Florence , Salmon Isabelle , Braun Michel Y.
Published: May 2010

CD3-negative NK cells are granular lymphocytes capable of producing inflammatory cytokines and killing malignant, infected, or stressed cells. We have recently observed a new role for NK cells in the control of the proliferation of CD4 T cells under persistent antigenic stimulation. Monoclonal anti-male CD4 T cells transferred into Rag2−/− male recipients did not expand or were rapidly eliminated. Remarkably, T cells transferred into NK cell-deficient Rag2−/− Il-2Rγc−/− male hosts expanded extensively and mediated tissue lesions usually observed in chronic graft-versus-host disease (GVHD). T cell failure to proliferate and to induce chronic GVHD was the result of NK cell activity, because depletion of the recipient’s NK1.1+ cells by Ab treatment induced T cell expansion and chronic GVHD. T cells under chronic Ag stimulation upregulated ligands of the activating receptor NKG2D, and regulatory activity of NK cells was inhibited by the injection of Abs directed to NKG2D. On the contrary, blocking NKG2A inhibitory receptors did not increase NK cell regulatory activity. Finally, we show that NK regulation of T cell expansion did not involve perforin-mediated lytic activity of NK cells, but depended on T cell surface expression of a functional Fas molecule. These results highlight the potential role played by NK cells in controlling the Ag-specific CD4+ T cells responsible for chronic GVHD.
Control of T Cell Reactivation by Regulatory Qa-1–Restricted CD8+ T Cells
Authors: Varthaman Aditi , Khallou-Laschet Jamila , Clement Marc , Fornasa Giulia , Kim Hye-Jung , Gaston Anh-Thu , Dussiot Michael , Caligiuri Giuseppina , Herbelin André , Kaveri Srinivas , Cantor Harvey , Nicoletti Antonino
Published: May 2010

Administration of attenuated pathogenic T cell clones, a procedure known as T cell vaccination, induces CD8+ T cells specific for peptides derived from the Vβ-chain of the TCR presented by the MHC class Ib molecule, Qa-1 expressed on the vaccine cells. These regulatory CD8+ T cells have the capacity to control the activation of endogenous T cells expressing the same TCR Vβ-chain as the vaccinating cells. We hypothesized that vaccination with NKT cells could also induce Qa-1–restricted CD8+ T cells that would control NKT cell activation. We tested this hypothesis in a murine model of Con A-induced hepatitis that is induced by NKT cells. Vaccination with NKT cells effectively induced protective Qa-1–restricted CD8+ T cells that prevented hepatitis. Surprisingly, upon vaccination with T cells expressing Vβ-chains irrelevant to NKT cells, we discovered that the specificity of vaccine-induced Qa-1–restricted CD8+ T cells was not limited to the Vβ-chain of the vaccinating cells. We further show that these regulatory Qa-1–restricted CD8+ T cells arise spontaneously upon polyclonal activation of T cells in the absence of deliberate T cell vaccination. These experiments provide new insight into a CD8+ T cell compartment that regulates the immediate reactivation of conventional T cells and NKT cells.
Bam32/DAPP1 Promotes B Cell Adhesion and Formation of Polarized Conjugates with T Cells
Authors: Al-Alwan Monther , Hou Sen , Zhang Ting-ting , Makondo Kennedy , Marshall Aaron J.
Published: May 2010

B cell Ag receptors function in both signaling activation of Ag-specific cells and in collecting specific Ag for presentation to T lymphocytes. Signaling via PI3K is required for BCR-mediated activation and Ag presentation functions; however, the relevant downstream targets of PI3K in B cells are incompletely defined. In this study, we have investigated the roles of the PI3K effector molecule Bam32/DAPP1 in BCR signaling and BCR-mediated Ag presentation functions. In mouse primary B cells, Bam32 was required for efficient activation of the GTPase Rac1 and downstream signaling to JNK, but not activation of BLNK, phospholipase C γ2, or calcium responses. Consistent with a role of this adaptor in Rac-mediated cytoskeletal rearrangement, Bam32 was required for BCR-induced cell adhesion and spreading responses on ICAM-1 or fibronectin-coated surfaces. The function of Bam32 in promoting Rac activation and adhesion required tyrosine 139, a known site of phosphorylation by Lyn kinase. After BCR crosslinking by Ag, Bam32-deficient B cells are able to carry out the initial steps of Ag endocytosis and processing, but show diminished ability to form Ag-specific conjugates with T cells and polarize F-actin at the B-T interface. As a result, Bam32-deficient B cells were unable to efficiently activate Ag-specific T cells. Together, these results indicate that Bam32 serves to integrate PI3K and Src kinase signaling to promote Rac-dependent B cell adhesive interactions important for Ag presentation function.
B Cell Receptor-Mediated Calcium Signaling Is Impaired in B Lymphocytes of Type Ia Patients with Common Variable Immunodeficiency
Authors: Foerster Christian , Voelxen Nadine , Rakhmanov Mirzokhid , Keller Baerbel , Gutenberger Sylvia , Goldacker Sigune , Thiel Jens , Feske Stefan , Peter Hans-Hartmut , Warnatz Klaus
Published: May 2010

Several lines of evidence have demonstrated B cell intrinsic activation defects in patients with common variable immunodeficiency (CVID). The rapid increase of intracellular free calcium concentrations after engagement of the BCR represents one crucial element in this activation process. The analysis of 53 patients with CVID for BCR-induced calcium flux identified a subgroup of patients with significantly reduced Ca2+ signals in primary B cells. This subgroup strongly corresponded to the class Ia of the Freiburg classification. Comparison at the level of defined B cell subpopulations revealed reduced Ca2+ signals in all mature B cell populations of patients with CVID class Ia when compared with healthy individuals and other groups of patients with CVID but not in circulating transitional B cells. BCR-induced Ca2+ responses were the lowest in CD21low B cells in patients as well as healthy donors, indicating an additional cell-specific mechanism inhibiting the Ca2+ flux. Although proximal BCR signaling events are unperturbed in patients’ B cells, including normal phospholipase Cγ2 phosphorylation and Ca2+ release from intracellular stores, Ca2+ influx from the extracellular space is significantly impaired. CD22, a negative regulator of calcium signals in B cells, is highly expressed on CD21low B cells from patients with CVID Ia and might be involved in the attenuated Ca2+ response of this B cell subpopulation. These data from patients with CVID suggest that a defect leading to impaired BCR-induced calcium signaling is associated with the expansion of CD21low B cells, hypogammaglobulinemia, autoimmune dysregulation, and lymphadenopathy.
Individual Variation in the Germline Ig Gene Repertoire Inferred from Variable Region Gene Rearrangements
Authors: Boyd Scott D. , Gaëta Bruno A. , Jackson Katherine J. , Fire Andrew Z. , Marshall Eleanor L. , Merker Jason D. , Maniar Jay M. , Zhang Lyndon N. , Sahaf Bita , Jones Carol D. , Simen Birgitte B. , Hanczaruk Bozena , Nguyen Khoa D. , Nadeau Kari C. , Egholm Michael , Miklos David B. , Zehnder James L. , Collins Andrew M.
Published: May 2010

Individual variation in the Ig germline gene repertoire leads to individual differences in the combinatorial diversity of the Ab repertoire, but the study of such variation has been problematic. The application of high-throughput DNA sequencing to the study of rearranged Ig genes now makes this possible. The sequencing of thousands of VDJ rearrangements from an individual, either from genomic DNA or expressed mRNA, should allow their germline IGHV, IGHD, and IGHJ repertoires to be inferred. In addition, where previously mere glimpses of diversity could be gained from sequencing studies, new large data sets should allow the rearrangement frequency of different genes and alleles to be seen with clarity. We analyzed the DNA of 108,210 human IgH chain rearrangements from 12 individuals and determined their individual IGH genotypes. The number of reportedly functional IGHV genes and allelic variants ranged from 45 to 60, principally because of variable levels of gene heterozygosity, and included 14 previously unreported IGHV polymorphisms. New polymorphisms of the IGHD3-16 and IGHJ6 genes were also seen. At heterozygous loci, remarkably different rearrangement frequencies were seen for the various IGHV alleles, and these frequencies were consistent between individuals. The specific alleles that make up an individual's Ig genotype may therefore be critical in shaping the combinatorial repertoire. The extent of genotypic variation between individuals is highlighted by an individual with aplastic anemia who appears to lack six contiguous IGHD genes on both chromosomes. These deletions significantly alter the potential expressed IGH repertoire, and possibly immune function, in this individual.
Cutting Edge: Lack of High Affinity Competition for Peptide in Polyclonal CD4+ Responses Unmasks IL-4 Production
Authors: Milner Joshua D. , Fazilleau Nicolas , McHeyzer-Williams Michael , Paul William
Published: May 2010

Priming of naive monoclonal CD4 T cells via weak agonsim permits GATA-3 transcription and Th2 differentiation. To test whether this process can occur in polyclonal naive populations, where a range of TCR affinities exists for any given Ag/MHC complex, we primed naive CD4 cells from 5CC7 Vβ3 transgenic mice, which have a fixed β-chain specific for pigeon cytochrome c peptide I-Ek. Priming populations de-pleted of higher affinity, moth cytochrome c pep-tide I-Ek tetramer-binding cells resulted in substantial IL-4 production that did not occur in the presence of higher affinity cells. TCRα-chain sequence analysis showed that clones that possessed TCR features associated with high affinity responses to pigeon cytochrome c made less IL-4 than clones that possessed fewer such motifs. These results indicate that cells bearing TCRs that are weakly stimulated by their cognate Ag preferentially adopt a Th2 phenotype when primed in the absence of competition from cells with higher affinity receptors.
Early Japanese contributions to space weather research (1945–1960)
Authors: Nishida A.
Published: May 2010

Abstract. Major contributions by Japanese scientists in the period of 1945 to 1960 are reviewed. This was the period when the foundation of the space weather research was laid by ground-based observations and theoretical research. Important contributions were made on such subjects as equatorial ionosphere in quiet times, tidal wind system in the ionosphere, formation of the F2 layer, VLF propagation above the ionosphere, and precursory phenomena (type IV radio outburst and polar cap absorption) to storms. At the IGY (1957, 1958), research efforts were intensified and new programs in space and Antarctica were initiated. Japanese scientists in this discipline held a tight network for communication and collaboration that has been kept to this day.
Inseparability of science history and discovery
Authors: Herndon J. M.
Published: May 2010

Abstract. Science is very much a logical progression through time. Progressing along a logical path of discovery is rather like following a path through the wilderness. Occasionally the path splits, presenting a choice; the correct logical interpretation leads to further progress, the wrong choice leads to confusion. By considering deeply the relevant science history, one might begin to recognize past faltering in the logical progression of observations and ideas and, perhaps then, to discover new, more precise understanding. The following specific examples of science faltering are described from a historical perspective: (1) Composition of the Earth's inner core; (2) Giant planet internal energy production; (3) Physical impossibility of Earth-core convection and Earth-mantle convection, and; (4) Thermonuclear ignition of stars. For each example, a revised logical progression is described, leading, respectively, to: (1) Understanding the endo-Earth's composition; (2) The concept of nuclear georeactor origin of geo- and planetary magnetic fields; (3) The invalidation and replacement of plate tectonics; and, (4) Understanding the basis for the observed distribution of luminous stars in galaxies. These revised logical progressions clearly show the inseparability of science history and discovery. A different and more fundamental approach to making scientific discoveries than the frequently discussed variants of the scientific method is this: An individual ponders and through tedious efforts arranges seemingly unrelated observations into a logical sequence in the mind so that causal relationships become evident and new understanding emerges, showing the path for new observations, for new experiments, for new theoretical considerations, and for new discoveries. Science history is rich in "seemingly unrelated observations" just waiting to be logically and causally related to reveal new discoveries.
Selective partial update and set‐membership improved proportionate normalized subband adaptive filter algorithms
Authors: Abadi Mohammad Shams Esfand
Published: May 2010

In this article, the concept of proportionate adaptation is extended to the selective partial update (SPU) and set‐membership (SM) normalized subband adaptive filters (NSAFs), and three proportionate normalized subband adaptive filter algorithms are established. The proposed algorithms are the improved proportionate NSAF (IPNSAF), the SPU improved proportionate NSAF (SPU‐IPNSAF), and the SM‐IPNSAF which are suitable for sparse system identification. When the impulse response of the echo path is sparse, the IPNSAF algorithm has faster convergence than NSAF. The performance of IPNSAF is also suitable for dispersive impulse responses. In SPU‐IPNSAF, the filter coefficients are partially updated rather than the entire filter at every adaptation which reduces the computational complexity of IPNSAF. The SM‐IPNSAF exhibits good performance with significant reduction in the overall computational complexity compared with the ordinary IPNSAF. The simulation results show good performance of the proposed algorithms. Copyright © 2010 John Wiley & Sons, Ltd.