bluuebunny/crossref_metadata_2025 huggingface dataset:
Book Review Recension de livre
Authors: Pasquero Jean
Published: September 2010

Méthodes de recherche en management. Thiétart, Raymond‐Alain et coll.

Doing Management Research—A Comprehensive Guide. Thiétart, Raymond‐Alain et al

This book is a fine achievement. Recently translated from the French and specially adapted to Anglophone audiences, it is now available in North America under the aegis of Sage Publications. The objective of the book—to provide a comprehensive yet simple guide for “doing management research”—is fully attained. The result of a three‐year collaboration among 22 European researchers, the book is built around the major issues that researchers preparing for a significant project must confront upon putting together a research proposal. One of its merits is its original combination of French clarity and North American pragmatism. The mix of soul‐searching issues, principles, techniques, and applications sets it apart from the current production in the field. Readers are always made aware of the choices they can make and the consequences of each choice for the future of their research project. Another merit of the book is its full integration across chapters, both in contents and style. The approach is unusually balanced, as quantitative and qualitative research methods are given equal status. The main pedagogical messages the book conveys are that research questions should drive methodology and not the other way around, that methodological purism is often unproductive, and that researchers must continually strive to maintain consistency between their objectives and their methods. A vast array of real research examples taken from empirical articles or monographs helps make sense of the issues discussed. For its exceptional integration between sound principles and practical methods, the book is definitely a must on the shelves of graduate students and professors of management alike.
Canadian Approaches to E‐Business Implementation
Authors: Grant Rebecca
Published: September 2010

As Web‐based business nears the decade mark, it is appropriate to take stock of its progress and the degree to which it has met or fallen short of predictions. This paper examines the extent to which companies have followed the advice of experts when it comes to designing an organizational structure for their e‐business initiatives. It compares the prevalence of centralized versus business unit level decision‐making in Canadian companies with e‐business experience. It also explores who is given responsibility for application development, backend integration, and infrastructure maintenance. The data demonstrate that use of independent contractors has increased. However, outsourcing in general is less prevalent than predicted and implementation driven by business units, rare. Furthermore, the practices of companies with well‐established initiatives differ significantly from those of the less experienced, offering important lessons for newcomers to e‐business.

Etant donné que le commerce basé sur la toile a presque dix ans, il est temps d'analyser son progrés et l'écart de résultat par rapport aux prédictions. La présente étude analyse quel a été le niveau de suivi des conseils d'expert par les entreprises en qui concerne la programmation des structures de mise en œuvre de leurs projets de commerce électronique. Elle compare la position dominante des décisions prises au niveau centralisée sur celles prises au niveau de la division spécialisée chez les entreprises canadiennes ayant une expérience en commerce électronique. Elle fait apparaître également à qui a été confiée la responsabilité du développement des logiciels, de l'étape finale de l'intégration et de l'entretien de l'infrastructure. Les données démontrent que l'emploi des entrepreneurs indépendants a augmenté. Cependant, la sous‐traitance n'est en général pas aussi forte que prévue et le développement assuré par les divisions spécialisées reste faible. En outre, la pratique des entreprises ayant des activités bien établies se distingue considérablement de celle qui ont moins d'expérience, offrant ainsi des leçons importantes pour les nouveaux venus du commerce électronique.
Hard and Soft Ways to Create Value from Information Flows: Lessons from the Canadian Financial Services Industry
Authors: Lejeune Albert , Roehl Tom
Published: September 2010

Over an extended period during the 1990s, using long interviews with the top management of five banks and secondary data, we studied the transformation of Canadian banks. We observed how the Canadian banks have changed to take full advantage of the increased technological potential for developing and exchanging information. The failure of the “pure players” has shown that the information advantages of the Internet are not sufficient to lead to sustainable competitive advantage. Existing financial institutions can make better use of that same information flow by combining it with organizational changes that make the new information more strategically valuable. By aligning information technology and the hard elements of their organizational architecture with soft elements like reputation, cooperation, and information sharing, traditional banks have developed powerful advantages in the 1990s.

Dans les années 90, nous avons utilisé des données secondaires et les longues entrevues que nous avons eues avec les hauts responsables de cinq banques pour étudier les mutations du paysage bancaire canadien. Nous nous sommes intéressé à la façon dont les banques canadiennes se sont restructurées pour pouvoir tirer le maximum d'avantages des potentialités croissantes des technologies de l'information. L'échec relatif des banques virtuelles a démontré que les avantages informationnels basés sur le réseau Internet ne suffisent pas pour donner lieu à des avantages concurrentiels durables. Las banques traditionnelles peuvent parvenir à faire un meilleur usage des mêmes flux informationnels en les combinant à des changements organisationnels qui rendent la nouvelle information plus stratégiquenient valable. En accommodant les technologies de l'information et les composantes permanentes (hard elements) de leur architecture organisationnelle avec les composantes fluctuantes (soft elements) telles que la réputation, la coopération, et la diffusion des informations, les banques traditionnelles se sont créé de puissants avantages stratégiques au cours des années 90.
M‐Commerce in Canada: An Interaction Framework for Wireless Privacy
Authors: Coursaris Constantinos , Hassanein Khaled , Head Milena
Published: September 2010

Mobile commerce (m‐commerce) is a natural extension of e‐commerce that allows users to interact with other users or businesses in a wireless mode, anytime/anywhere. The Canadian market, with its high rates of technology acceptance, should be a fertile ground for m‐commerce growth. This paper will examine m‐commerce in the Canadian landscape, focusing on wireless privacy issues. We start with an introduction of m‐commerce and an examination of its similarities and differences with e‐commerce. An overview is presented of the Canadian landscape for both e‐commerce and m‐commerce, followed by a discussion of the needs and concerns of the mobile consumer (m‐consumer). We then examine privacy issues associated with e‐commerce and identify additional privacy concerns that arise due to the wireless nature of the m‐commerce environment. Consequently, a new wireless privacy interaction framework is introduced which reflects the nature of interactions taking place between parties within a wireless environment. The responsibilities of the interaction parties towards enhancing the privacy of the m‐consumer are then outlined. The paper ends with some conclusions and potential directions for future research.

Le commerce mobile (commerce‐m) est une excroissance naturelle du commerce électronique qui permet, en tout et en tous lieux, la communication sans fil entre ses utilisateurs. Le marché canadien, marqué par des taux élevés d'intégration technologique, est un terrain de prédilection pour le développement de ce nouveau type de commerce. Le présent article, qui met l'accent sur les questions de confidentialité likes à la communication sans fil, analyse la situation du commerce mobile au Canada. Nous commençons notre étude par une définition du concept de commerce mobile et un examen des points de ressemblances et de différences entre celui‐ci et le commerce électronique. Ensuite, nous proposons un aperçu général du commerce électronique et du commerce mobile dans le paysage canadien, suivi d'une analyse des besoins et des soucis des consommateurs du commerce électronique (consommateurs mobiles). Plus loin nous examinons les problemes de confidentialité liés au commerce électronique, et les problmes supplémen‐taires générés par le caract2re sans $1 du commerce mobile. C'est pourquoi nous introduisons un nouveau cadre d'interaction de la confidentialité sans fil, cadre qui refltte la nature des interactions qui existent entre les parties dans un environnement pareil. A ce niveau, nous insistons sur les responsabilités des parties prenantes dans le renforcement de la confidentialité du commerce mobile. Nous aclzevons notre dude par quelques conclusions et des propositions de pistes potentielles de recherche s futures.
The Moderating Effect of Different Forms of Commitment on Role Ambiguity‐Job Tension Relations
Authors: Irving P. Gregory , Coleman Daniel F.
Published: September 2010

Whereas some authors have suggested that organizational commitment might have a buffering effect on stressor‐strain relations, others have suggested that commitment may exacerbate these relations. We examined the potential moderating effect of different forms of organizational commitment on relations between role ambiguity (a particular form of stressor) and job tension (an outcome of stress) in an organization that was undergoing significant change. We surveyed 225 individuals working for a public‐sector organization that was being partially privatized. Results supported the hypothesis that continuance commitment exacerbates relations between role ambiguity and job tension. Contrary to our hypothesis, affective commitment also exacerbated these relations.

Alors que certains auteurs laissent entendre que l'engagement organisationnel aurait un effet tampon sur les relations entre les agents stressants et la tension (stressor‐strain relations), d'autres suggèrent que l'engagement peut exacerber ces rapports. Nous avons examiné l'effet modérateur que peuvent avoir différents types d'engagement organisationnel sur les relations entre l'ambiguïte du rôle (un genre particulier d'agent stressant) et la tension au travail (un résultat du stress) au sein d'un organisme subissant des changements profonds. Nous avons effectué un sondage auprès de 225 personnes travaillant au sein d'un organisme du secteur public qui était en voie d'être privatisé. Les résultats ont confirmé l'hypothèse suggérant que l'engagement de continuité (continuance commitment) exacerbe les relations entre l'ambiguïté du rôle et la tension au travail. Contrairement è notre hypothèse, l'engagement affectif (affective commitment) a également exacerbé ces relations.
Les déeterminants des intentions de depart des femmes cadres: differents ou non de ceux de leurs collegues masculins?
Authors: Rinfret Natalie , Lortie‐Lussier Monique
Published: September 2010

C'est un fait reconnu que les femmes cadres sont plus nombreuses que les hommes a quitter leur emploi. Une enquete aupres de 298 cadres d'entreprises quebecois (151 femmes, 147 hommes) qui en avaient exprime I'intention, avait pour objectif d'identifier les motifs propres a ceux des femmes, en les comparand a ceux des hommes. Les femmes se sont declarees aussi satisfaites de leur travail que les hommes. Comme pour eux, une mauvaise relation de travail avec le superieur immediat constitue la raison principale de I'intention de depart. Au‐dela de ces points communs, les resultats d'analyses de regression hierarchique, effectuees separement pour les deux sexes, revelent que les femmes ont des raisons qui se demarquent de celles des hommes. Elles sont liees a un niveau hierarchique peu eleve, a une estimation elevee de leur competence, a leur isolement et au peu de consideration de leur contribution a la culture organisationnelle. Les resultats sont examines a la lumiere des inegalites constatees dans la situation professionnelle des repondantes dont le salaire et le niveau hierarchique sont remarquablement inferieurs a ceux des hommes. Les implications organisationnelles de cet ensemble de raisons sont egalement analysees.

It is widely known that women executives are more inclined to quit their positions than are their male counterparts. A sample of 298 Quebecois managers (151 women and 147 men) who had expressed the intention to leave their organization took part in a survey conducted to uncover the reasons behind women's decisions to quit. These reasons are compared with men's. Although the level of satisfaction with work was high for both sexes, a poor relationship with one's supervisor stands out as the main reason for turnover intentions for both sexes. Despite these similarities, results of hierarchical regressions performed separately for both sexes suggest that women have specific motives for quitting—isolation in the workplace, lack of recognition of their contribution to the culture of the organization, low position in the hierarchy of the organization, and their highly positive evaluation of their competence. Results are discussed in the light of sex differences regarding salary and position level, which were found to be significantly lower among women. The organizational implications of this pattern of reasons are also discussed.
The Effect of Environmental Turbulence and Leader Characteristics on International Performance: Are Knowledge‐Based Firms Different?
Authors: Kuivalainen Olli , Sundqvist Sanna , Puumalainen Kaisu , Cadogan John W.
Published: September 2010

The aim of this paper is to study the effect of environmental turbulence and leader characteristics on international performance. It is suggested that these phenomena explain the differences between knowledge‐intensive companies and traditional industrial enterprises in the internationalization process. The empirical part of the study is based on a large cross‐industrial survey of Finnish small and medium‐sized enterprises. Our results indicate that knowledge‐intensive firms have experienced more intensive international growth than other firms. They are also operating in an environment in which technological turbulence is significantly higher, and their leaders put more emphasis on internationalization. Generally, environmental turbulence is a better indicator of international performance in knowledge‐intensive firms than in others.

Dans le présent article, nous étudions l'impact de la turbulence environnementale et des caractéristiques des leaders sur la performance internationale. On estime que ces phénomènes rendent compte des différences qui existent, dans le processus d'internationalisation, entre les entreprises à forte concentration de savoir et les entreprises industrielles traditionnelles. La partie empirique de l'étude s'appuie sur une grande enquête trans‐industrielle de petites et moyennes entreprises finnoises. Nos résultats indiquent que les entreprises à forte concentration de savoir connaissent une croissance internationale plus grande que les autres entreprises. L'étude montre aussi que les entreprises à forte concentration de savoir opèrent dans un environnement marqué par une plus grande turbulence technologique. Par ailleurs, leurs leaders mettent plus l'accent sur l'internationalisation. D'une façon générale, la turbulence environnementale permet de mieux apprécier la performance internationale dans les entreprises à forte concentration de savoir que dans d'autres entreprises.
Efficiency and Personalization as Value Creation in Internationalizing High‐Technology SMEs
Authors: Spence Martine
Published: September 2010

This article investigates the sources of value creation in the exchange relationships between internationalizing Canadian small high‐technology firms and their various stakeholders. The paper reviews the concepts of exchange and value, and applies these concepts to small internationalizing high‐technology businesses. The data are based on semi‐structured interviews with 20 Canadian high‐technology small and medium‐sized enterprises (HTSMEs). The analysis shows that HTSMEs strive to attain internal and external efficiency. Efficiency, however, is a subset of Personalization, which consists of developing close relationships with dedicated partners in order to create sustainable value. This study demonstrates that value creation for HTSMEs is not only a matter of creating products at the cutting edge, but primarily of managing a constellation of relationships within evolving networks.

La présente étude recherche les sources de création de valeur dans les relations d'échange entre les petites entreprises canadiennes à haute technologie en voie d'internationalisation et les différentes parties prenantes. Elle passe en revue les concepts d'échange et de valeur qu'elle applique aux petites entreprises à haute technologie en voie d'internationalisation. Les données sont fondées sur des entretiens semi‐structurées réalisée auprès de 20 petites et moyennes entreprises canadiennes à haute technologie (HTSME). L'analyse montre que les HTSME recherchent laborieusement l'efficacité interne et externe. Mais cette efficacité est une sous‐variante de la Personnalisation qui consiste à développer des relations privilégiées avec des partenaires dévoués, afin de créer une valeur durable. Notre étude démontre que la création de valeur pour les HTSME n'est pas seulement synonyme de création de produit d'avantgarde. Elle signifie aussi et surtout gestion d'une constellation de relations dans des réseaux en évolution.
Revisiting Shareholder Value Creation via International Joint Ventures: Examining Interactions Among Firm‐ and Context‐Specific Variables
Authors: Merchant Hemant
Published: September 2010

This study attempts to empirically reconcile the prevalent mixed findings regarding reactions of capital markets to announcements of American firms' participation in international joint ventures (IJVs). It does so by first admitting salient contextual variables into the portfolio of firm‐specific variables—heretofore mostly considered in isolation—and then modeling their collective impact on these parents' shareholder value. A cluster analysis of more than 700 equity IJVs yields findings that highlight important interactions between the two sets of variables, which better inform creation and destruction of shareholder value for IJV parents. These findings facilitate development of a conceptual framework for assessing how parents can exploit the inter‐connectedness between their firm‐specific and contextual domains. Thus, this study lays a foundation for generating more refined predictions about shareholder value creation via IJVs.

La présente étude essaie de concilier, de façon empirique, les conclusions contradictoires, révélées par l'étude des réactions des marchés de capitaux aux annonces par les firmes américaines de leur participation aux coentreprises internationales. Elle y parvient en deux temps: premièrement, par la reconnaissance des variables contextuelles fondamentales, jusque‐là surtout considérées de façon isolée, dans le portfolio des variables spécifiques aux firmes; deuxièmement, par la modélisation de leur impact collectif sur la création des valeurs pour les actionnaires des firmes impliquées dans ces coentreprises. Les conclusions tirées de l'analyse par segments de plus de 700 coentreprises boursières internationales mettent en évidence d'importantes interactions (entre les deux groupes de variables) dans la création et la destruction des valeurs pour les actionnaires des coentreprises internationales. De façon incidente, les conclusions de l'étude tracent les contours d'un cadre conceptuel permettant de montrer comment les partenaires peuvent exploiter l'interrelation entre leurs secteurs spécifiques et les domaines contextuels. En somme, l'étude jette les bases d'une meilleure capacité de prédiction dans la création des valeurs par les actionnaires, via les coentreprises internationales.
The Market Value Implications of Post‐Retirement Benefit Plans and Plan Surpluses — Canadian Evidence
Authors: Wiedman Christine I. , Wier Heather A.
Published: September 2010

We examine a sample of Canadian firms with defined benefit pension plans over 2000 and 2001, using note disclosures available for the first time in Canada in 2000, and find the following: On average, Canadian investors appear to view the deficit arising from under‐funded plans as a liability of the sponsoring firm, but do not appear to view the surplus arising from over‐funded plans as an asset of the firm. This finding is consistent with the legal constraints faced by Canadian firms attempting to withdraw a pension surplus from plans. Additionally, we document that post‐retirement benefits other than pensions are largely unfunded in Canada, but are not consistently priced by the market. This latter result may be attributable to lack of investor confidence in the estimation of these liabilities. Our findings on defined benefit pension plans surpluses support current International Accounting Standards Board proposals on applying an asset ceiling test to pension surpluses.

La présente étude utilise les informations annexes disponibles au Canada pour la premiére fois en 2000 pour analyser un échantillon d'entreprises canadiennes dotées, entre 2000 et 2001, de régimes de retraite àA prestations déterminées. L'étude révèle qu'en moyenne, les investisseurs canadiens ont tendance à considérer le déficit résultant des régimes sous‐capitalisés comme une responsabilité des firmes promotrices; en revanche. ils refusent de considérer l'excédent résultant des régimes surcapitalisés comme un atout pour ces firmes. Cette attitude est attribuable aux contraintes juridiques auxquelles sont soumises les firmes canadiennes qui essaient de puiser le surplus des caisses de retraites. L'étude démontre que hormis les prestations de retraite, les indemnityés à la retraite manquent cruellement de capitaux au Canada et sont sous‐évaluées parle marché. Ce dernier résultat peut être attribué au fait que les investisseurs n'ont pas foi en l'évaluation de leur passif. En ce qui conceme les excédents des régimes de retraites à prestations déterminées, nos conclusions vont dans le même sens que les propositions du Comité international de normalisation de la comptabilité qui recommandent I'application d'un test de plafonnement aux excédents des régimes de pensions.
Consumer Perceptions of Promotional Offers in the Performing Arts: An Experimental Approach
Authors: D'Astous Alain , Legoux Renaud , Colbert François
Published: September 2010

This article reports the results of an experimental study in which four characteristics of sales promotions in the performing arts were manipulated: the type of promotion, the type of performance, the attractiveness of the performance, and the fit between the promotion and the performance. The results show that these factors had interactive effects on consumer reactions. Thus, although the fit between the promotion and the performance had a generally positive impact on consumer appreciation of the promotional offer, this effect was more important when the performance was more attractive. Sales promotions that closely fit the performing arts category were less likely to be perceived as manipulative when the performances were less attractive. We conclude that more research is needed on this managerially relevant topic in light of the complex dynamics that appear to underlie the relationships between the characteristics of sales promotions and consumer reactions.

Cet article présente les résultats d'une étude expérimentale dans laquelle quatre facettes d'une promotion des ventes dans le contexte des arts de la scène ont été manipulées: le type de promotion, le type de performance, l'attrait de la performance et le lien entre la promotion et la performance. Les résultats montrent que ces facteurs ont des effets interactifs sur les réactions des consommateurs. Ainsi, même si le lien entre la promotion et la performance a un impact positif sur l'appréciation d'une offre promotionnelle, cet impact est plus important lorsque la performance est plus attrayante. Les promotions des ventes qui ont un lien fort avec le type d'art de la scène sont moins susceptibles d'être perçues comme des tentatives de manipulation. On conclut qu'il est nécessaire defaire plus de recherche sur ce sujet qui est pertinent pour les gestionnaires étant donné l'apparente complexité qui sous‐tend les relations entre les caractéristiques des promotions des ventes et les réactions des consommateurs.
Effects of Private and Public Canadian Mergers
Authors: Yuce Ayse , Ng Alex
Published: September 2010

This paper examines the merger announcements of Canadian companies between 1994 and 2000 during an exceptional merger boom. The results show that both the target companies and the acquirer companies obtain significant positive abnormal returns during this time period. Companies that acquire private targets with stock have positive returns; however, acquirers of private firms have significantly higher risk compared with those that acquire public targets, despite nonsignificant differences in returns. Acquirers pay significantly less to acquire private firms than public firms, especially with stock. Overall, the findings suggest there is support for a liquidity discount for private firms, and the market is efficient in valuing firms in asymmetric conditions.

Dans cet article, nous examinons les annonces de fusions des compagnies canadiennes entre 1994 et 2000, période de grand boom de fusion. Les résultats montrent qu'au cours de cette période, les compagnies cibles et les compagnies acquéreuses obtiennent des rendements anormaux positifs. Les entreprises qui achètent des cibles privées avec des actions ont des rendements positifs; cependant, ces entreprises ont des risques considérablement plus élevés par rapport aux entreprises qui achètent des cibles publiques nonobstant des différences négligeables dans les rendements. Par ailleurs, les acquéreurs paient nettement moins pour acheter les entreprises privées que pour acheter les entreprises publiques, en particulier celles qui ont des actions. Dans l'ensemble, les résultats de l'étude révèlent qu'il est nécessaire d'escompter la liquidité pour les entreprises privées et que le marché permet de valoriser les entreprises dans les conditions asymétriques.
Enhancing the Bounce of a Ball
Authors: Cross Rod
Published: September 2010

In sports such as baseball, softball, golf, and tennis, a common objective is to hit the ball as fast or as far as possible. Another common objective is to hit the ball so that it spins as fast as possible, since the trajectory of the ball through the air is strongly affected by ball spin.1 In an attempt to enhance both the coefficient of restitution (COR) and the spin of a golf ball, I conducted several experiments to see what would happen when a 45-g, 42.8-mm diameter golf ball bounced on: (a) a 58-mm diameter, 103-g Super Ball®; (b) an 8-mm thick, 56-mm diameter circular disk of Super Ball material cut from a large Super Ball and glued to a 3.4-kg lead brick; and (c) a 3-mm thick sheet of rubber glued to a 3.4-kg lead brick. (See Fig. 1.)
Investigating Flight with a Toy Helicopter
Authors: Liebl Michael
Published: September 2010

Flight fascinates people of all ages. Recent advances in battery technology have extended the capabilities of model airplanes and toy helicopters. For those who have never outgrown a childhood enthusiasm for the wonders of flight, it is possible to buy inexpensive, remotely controlled planes and helicopters. A toy helicopter offers an opportunity to investigate and study some basics of flight.1
To accelerate or not to accelerate? That is the question
Authors: Riendeau Diane
Published: September 2010

Thanks to Jim Hicks, Barrington High School, and Jaime Stasiorowski and Kristen Piggott, Deerfield High School, for their help with this month's column. If you have a YouTube video you use in class, please send the link and a brief description to: driendeau@dist113.org.
Family Planning and the Millennium Development Goals
Authors: Cates Willard , Abdool Karim Quarraisha , El-Sadr Wafaa , Haffner Debra W. , Kalema-Zikusoka Gladys , Rogo Khama , Petruney Tricia , Averill E. Megan Davidson
Published: September 2010

To alleviate global poverty, investments and partnerships in family planning are needed.
ASYMPTOTICS FOR FERMI CURVES: SMALL MAGNETIC POTENTIAL
Authors: DE OLIVEIRA GUSTAVO
Published: September 2010

We consider complex Fermi curves of electric and magnetic periodic fields. These are analytic curves in ℂ2 that arise from the study of the eigenvalue problem for periodic Schrödinger operators. We characterize a certain class of these curves in the region of ℂ2 where at least one of the coordinates has "large" imaginary part. The new results in this work extend previous results in the absence of magnetic field to the case of "small" magnetic field. Our theorems can be used to show that generically these Fermi curves belong to a class of Riemann surfaces of infinite genus.
THE EFFECT OF PINNING CONTROL ON EVOLUTIONARY PRISONER'S DILEMMA GAME
Authors: DU WEN-BO , ZHOU HONG , LIU ZHEN , CAO XIAN-BIN
Published: September 2010

The evolutionary game on graphs provides a natural framework to investigate the cooperation behavior existing in natural and social society. In this paper, degree-based pinning control and random pinning control are introduced into the evolutionary prisoner's dilemma game on scale-free networks, and the effects of control mechanism and control cost on the evolution are studied. Numerical simulation shows that forcing some nodes to cooperate (defect) will increase (decrease) the frequency of cooperators. Compared with random pinning control, degree-based pinning control is more efficient, and degree-based pinning control costs less than random pinning control to achieve the same goal. Numerical results also reveal that the evolutionary time series is more stable under pinning control mechanisms, especially under the degree-based pinning control.
THE ISOSPIN DIFFUSION IN 58Ni-INDUCED REACTIONS AT INTERMEDIATE ENERGIES
Authors:   INDRA Collaboration, GALICHET E. , RIVET M. F. , BORDERIE B. , COLONNA M. , BOUGAULT R. , DURAND D. , LE NEINDRE N. , LOPEZ O. , MANDUCI L. , VIENT E. , CHBIHI A. , FRANKLAND J. D. , WIELECZKO J. P. , DAYRAS R. , VOLANT C. , GUINET D. C. R. , LAUTESSE P. , PARLOG M. , ROSATO E. , VIGILANTE M.
Published: September 2010

Isospin diffusion is probed as a function of the dissipated energy by studying two systems 58 Ni +58 Ni and 58 Ni +197 Au , over the incident energy range 52-74A MeV. Experimental data are compared with the results of a microscopic transport model with two different parameterizations of the symmetry energy term. A better overall agreement between data and simulations is obtained when using a symmetry term with a potential part linearly increasing with nuclear density. The isospin equilibration time at 52 A MeV is estimated to 130 ± 10 fm/c.
CONSTRAINING THE DENSITY DEPENDENCE OF THE SYMMETRY ENERGY WITH NUCLEAR STRUCTURE PROPERTIES
Authors: JIANG WEI-ZHOU
Published: September 2010

In this work, we review a few structural properties in finite nuclei and nuclear matter that are sensitive to differences in the symmetry energy, and discuss mechanisms that can enhance the sensitivity to differences in the symmetry energy with the relativistic mean-field model. Emphasis has been placed on the establishment of the relationship between the deexcitation energy of superdeformed secondary minima and the density dependence of the symmetry energy.
SIGMA MESON PRODUCTION IN PROTON-NUCLEUS COLLISIONS
Authors: SRISAWAD PORNRAD , ZHENG YU-MING , FUCHS CHRISTIAN , FAESSLER AMAND , YAN YUPENG , KOBDAJ CHINORAT , XING YONG-ZHONG
Published: September 2010

The sigma meson production is investigated in p + 40 Ca and p + 208 Pb at the incident energy 1.5 GeV within the Quantum Molecular Dynamics model. The simulation results indicate a distinctive A dependence of the sigma production that the increase of A is followed by an increase of the production cross section. We find that the sigma meson production is strongly medium dependent and the produced sigma mesons decaying in a dense medium experience a stronger mass shift towards lower masses. This mass shift is an experimentally accessible observable in the final state pion pairs, which did not suffer absorption by the surrounding nucleons. It is pointed out that the ratio of measured sigma cross-sections as a function of the sigma invariant-mass from various reactions is a good probe to explore the existence of the sigma meson in dense nuclear environment.
EVENT-BY-EVENT FLUCTUATIONS OF NET-BARYON DISTRIBUTION AND HIGHER ORDER CUMULANTS
Authors: ZHOU YOU , WU KEJUN , LIU FENG
Published: September 2010

We analyze fluctuations of net baryon distribution as well as its higher order cumulants, the 2rd order(c2), 4th order cumulants(c4) and other variant high order cumulants like Skewness, Kurtosis, R4,2 as a function of the collision centrality. At the same time, we study the results of transverse momentum and rapidity cut effects of all observables. We argue that Skewness and Kurtosis are promising observables in experiments considering to their independence of acceptance. Beam energy dependences of Skewness and Kurtosis have been studied, these works provide baseline predictions for the forthcoming RHIC Beam Energy Scan program.
Lipopolysaccharide binding protein inhibitory peptide protects against acetaminophen-induced hepatotoxicity
Authors: Su G. L. , Hoesel L. M. , Bayliss J. , Hemmila M. R. , Wang S. C.
Published: September 2010

Acetaminophen (APAP)-induced liver injury remains the main cause of acute liver failure in the United States. Our previous work demonstrated that LPS binding protein (LBP) knockout mice are protected from APAP-induced hepatotoxicity. LBP is known to bind avidly to LPS, facilitating cellular activation. In this study, we sought to specifically inhibit the interaction between LBP and LPS to define the role of this interaction in APAP-induced liver injury. The peptide LBPK95A was able to inhibit LBP-mediated LPS activation of RAW 267.4 cells in a dose-dependent manner in vitro. In vivo, C57Bl/6 mice were treated with either LBPK95A or vehicle control concurrently with the administration of APAP (350 mg/kg). Mice treated with LBPK95A had significantly lower serum aspartate aminotransferase and alanine aminotransferase levels. Morphometric analysis of the liver tissue showed significantly less liver injury in mice treated with LBPK95A. To assess whether the LBPK95A altered glutathione depletion and APAP metabolism, we measured total glutathione levels in the liver after APAP. We found no difference in the glutathione levels and APAP-adduct formation between LBPK95A vs. vehicle control both at baseline and after APAP. In conclusion, our results support the hypothesis that LBP-induced liver injury after APAP is due to its ability to mediate activation by endogenous LPS. Our results suggest that blocking LBP-LPS interactions is a potential therapeutic avenue for the treatment of APAP-induced liver injury.
Combination of starvation interval and food volume determines the phase of liver circadian rhythm in Per2::Luc knock-in mice under two meals per day feeding
Authors: Hirao Akiko , Nagahama Hiroki , Tsuboi Takuma , Hirao Mizuho , Tahara Yu , Shibata Shigenobu
Published: September 2010

Although the circadian liver clock is entrained by the feeding cycle, factors such as food volume and starvation interval are poorly understood. Per2::Luc knock-in mice were given two meals per day with different food volume sizes and/or with different intervals of starvation between two mealtimes with the total food volume per day fixed at 3.6 g (80 food pellets, ∼75% of free feeding) per mouse. The bioluminescence rhythm in the liver produced a unimodal peak but not bimodal peak under the regimen of two meals per day over 14–15 days. Peak Per2 expression occurred concurrently with the mealtime of the larger food volume, when the first and second meal were given as different food volume ratios under a 12 h feeding interval. When an equal volume of food was given under different starvation interval (8 h:16 h), the peak of the Per2 rhythm was close to peak by mealtime after long starvation (16 h). When food volumes for each mealtime were changed under 8 h:16 h, the peak rhythm was influenced by combined factors of food volume and starvation interval. Food intake after the 16-h starvation caused a significant increase in liver Per2, Dec1, and Bmal1 gene expression compared with food intake after the 8-h starvation with 8 h:16 h feeding intervals. In conclusion, the present results clearly demonstrate that food-induced entrainment of the liver clock is dependent on both food volume and the starvation interval between two meals. Therefore, normal feeding habits may help to maintain normal clock function in the liver organ.
Hedgehog signaling regulates E-cadherin expression for the maintenance of the actin cytoskeleton and tight junctions
Authors: Xiao Chang , Ogle Sally A. , Schumacher Michael A. , Schilling Neal , Tokhunts Robert A. , Orr-Asman Melissa A. , Miller Marian L. , Robbins David J. , Hollande Frederic , Zavros Yana
Published: September 2010

In the stomach, strictly regulated cell adherens junctions are crucial in determining epithelial cell differentiation. Sonic Hedgehog (Shh) regulates epithelial cell differentiation in the adult stomach. We sought to identify whether Shh plays a role in regulating adherens junction protein E-cadherin as a mechanism for epithelial cell differentiation. Mouse nontumorigenic gastric epithelial (IMGE-5) cells treated with Hedgehog signaling inhibitor cyclopamine and anti-Shh 5E1 antibody or transduced with short hairpin RNA against Skinny Hedgehog (IMGE-5Ski) were cultured. A mouse model expressing a parietal cell-specific deletion of Shh (HKCre/ShhKO) was used to identify further changes in adherens and tight junctions. Inhibition of Hedgehog signaling in IMGE-5 cells caused loss of E-cadherin expression accompanied by disruption of F-actin cortical expression and relocalization of zonula occludens-1 (ZO-1). Loss of E-cadherin was also associated with increased proliferation in IMGE-5Ski cells and increased expression of the mucous neck cell lineage marker MUC6. Compared with membrane-expressed E-cadherin and ZO-1 protein in controls, dissociation of E-cadherin/β-catenin and ZO-1/occludin protein complexes was observed in HKCre/ShhKO mice. In conclusion, we demonstrate that Hedgehog signaling regulates E-cadherin expression that is required for the maintenance of F-actin cortical expression and stability of tight junction protein ZO-1.
Contrasting vascular effects caused by loss of Bardet-Biedl syndrome genes
Authors: Beyer Andreas M. , Guo Deng-Fu , Sheffield Val C. , Rahmouni Kamal
Published: September 2010

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous, autosomal-recessive disorder associated with several clinical features including obesity, hypertension, and cardiovascular abnormalities. BBS proteins play an important role in the function of cilia, a mechanosensory organelle in endothelial cells, but whether these proteins are directly involved in the regulation of vascular function is unclear. Here, we show that Bbs genes (1–12) are expressed in endothelial and smooth muscle cell lines and tissues enriched in endothelial (lung) and smooth muscle (stomach) cells as well as the aorta. Next, we used aortic rings to examine the vascular function of two BBS mouse models that recapitulate the human phenotype, namely Bbs2−/− (obese and normotensive) and Bbs6−/− (obese and hypertensive) mice. Interestingly, the endothelium-dependent relaxation (induced by ACh) was significantly enhanced in Bbs2−/− but not Bbs6−/− mice. In contrast, the endothelium-independent relaxation (induced by sodium nitroprusside) was unaltered in both BBS mouse models. In addition, the contractile responses to serotonin and endothelin-1 were attenuated in Bbs2−/− but not Bbs6−/− mice. Of note, the NO-producing enzymes (eNOS and iNOS) were upregulated in the aorta of Bbs2−/− but not Bbs6−/− mice. On the other hand, the expression level of membrane subunits of NADPH oxidase (p22phox and p47phox) in the aorta was decreased in Bbs2−/− mice but increased in Bbs6−/− mice. In conclusion, these data implicate Bbs genes in the regulation of vascular function and demonstrate that disrupting Bbs2 and Bbs6 genes affect differentially the vascular function.
2,3′,4,5′-Tetramethoxystilbene prevents deoxycorticosterone-salt-induced hypertension: contribution of cytochrome P-450 1B1
Authors: Sahan-Firat Seyhan , Jennings Brett L. , Yaghini Fariborz A. , Song Chi Young , Estes Anne M. , Fang Xiao R. , Farjana Nasreen , Khan Amir I. , Malik Kafait U.
Published: September 2010

Reactive oxygen species (ROS) contribute to various models of hypertension, including deoxycorticosterone acetate (DOCA)-salt-induced hypertension. Recently, we have shown that ROS, generated by cytochrome P-450 1B1 (CYP1B1) from arachidonic acid, mediate vascular smooth muscle cell growth caused by angiotensin II. This study was conducted to determine the contribution of CYP1B1 to hypertension and associated pathophysiological changes produced by DOCA (30 mg/kg) given subcutaneously per week with 1% NaCl + 0.1% KCl in drinking water to uninephrectomized rats for 6 wk. DOCA-salt treatment increased systolic blood pressure (SBP). Injections of the selective inhibitor of CYP1B1, 2,3′,4,5′-tetramethoxystilbene (TMS; 300 μg/kg ip every 3rd day) initiated at the 4th week of DOCA-salt treatment normalized SBP and decreased CYP1B1 activity but not its expression in the aorta, heart, and kidney. TMS also inhibited cardiovascular and kidney hypertrophy, prevented the increase in vascular reactivity and endothelial dysfunction, and minimized the increase in urinary protein and K+ output and the decrease in urine osmolality, Na+ output, and creatinine clearance associated with DOCA-salt treatment. These pathophysiological changes caused by DOCA-salt treatment and associated increase in vascular superoxide production, NADPH oxidase activity, and expression of NOX-1, and ERK1/2 and p38 MAPK activities in the aorta, heart, and kidney were inhibited by TMS. These data suggest that CYP1B1 contributes to DOCA-salt-induced hypertension and associated pathophysiological changes, most likely as a result of increased ROS production and ERK1/2 and p38 MAPK activity, and could serve as a novel target for the development of agents like TMS to treat hypertension.
Myocardial insulin resistance induced by high fat feeding in heart failure is associated with preserved contractile function
Authors: Christopher Bridgette A. , Huang Hsuan-Ming , Berthiaume Jessica M. , McElfresh Tracy A. , Chen Xiaoqin , Croniger Colleen M. , Muzic Raymond F. , Chandler Margaret P.
Published: September 2010

Previous studies have reported that high fat feeding in mild to moderate heart failure (HF) results in the preservation of contractile function. Recent evidence has suggested that preventing the switch from fatty acid to glucose metabolism in HF may ameliorate dysfunction, and insulin resistance is one potential mechanism for regulating substrate utilization. This study was designed to determine whether peripheral and myocardial insulin resistance exists with HF and/or a high-fat diet and whether myocardial insulin signaling was altered accordingly. Rats underwent coronary artery ligation (HF) or sham surgery and were randomized to normal chow (NC; 14% kcal from fat) or a high-fat diet (SAT; 60% kcal from fat) for 8 wk. HF + SAT animals showed preserved systolic (+dP/d t and stroke work) and diastolic (−dP/d t and time constant of relaxation) function compared with HF + NC animals. Glucose tolerance tests revealed peripheral insulin resistance in sham + SAT, HF + NC, and HF + SAT animals compared with sham + NC animals. PET imaging confirmed myocardial insulin resistance only in HF + SAT animals, with an uptake ratio of 2.3 ± 0.3 versus 4.6 ± 0.7, 4.3 ± 0.4, and 4.2 ± 0.6 in sham + NC, sham + SAT, and HF + NC animals, respectively; the myocardial glucose utilization rate was similarly decreased in HF + SAT animals only. Western blot analysis of insulin signaling protein expression was indicative of cardiac insulin resistance in HF + SAT animals. Specifically, alterations in Akt and glycogen synthase kinase-3β protein expression in HF + SAT animals compared with HF + NC animals may be involved in mediating myocardial insulin resistance. In conclusion, HF animals fed a high-saturated fat exhibited preserved myocardial contractile function, peripheral and myocardial insulin resistance, decreased myocardial glucose utilization rates, and alterations in cardiac insulin signaling. These results suggest that myocardial insulin resistance may serve a cardioprotective function with high fat feeding in mild to moderate HF.
Controlling matrix formation and cross-linking by hypoxia in cardiovascular tissue engineering
Authors: van Vlimmeren Marijke A. A. , Driessen-Mol Anita , Broek Marloes van den , Bouten Carlijn V. C. , Baaijens Frank P. T.
Published: September 2010

In vivo functionality of cardiovascular tissue engineered constructs requires in vitro control of tissue development to obtain a well developed extracellular matrix (ECM). We hypothesize that ECM formation and maturation is stimulated by culturing at low oxygen concentrations. Gene expression levels of monolayers of human vascular-derived myofibroblasts, exposed to 7, 4, 2, 1, and 0.5% O2( n = 9 per group) for 24 h, were measured for vascular endothelial growth factor (VEGF), procollagen α1(I) and α1(III), elastin, and cross-link enzymes lysyl oxidase (LOX) and lysyl hydroxylase 2 (LH2). After 4 days of exposure to 7, 2, and 0.5% O2( n = 3 per group), protein synthesis was evaluated. All analyses were compared with control cultures at 21% O2. Human myofibroblasts turned to hypoxia-driven gene expression, indicated by VEGF expression, at oxygen concentrations of 4% and lower. Gene expression levels of procollagen α1(I) and α1(III) increased to 138 ± 26 and 143 ± 19%, respectively, for all oxygen concentrations below 4%. At 2% O2, LH2 and LOX gene expression levels were higher than control cultures (340 ± 53 and 136 ± 29%, respectively), and these levels increased even further with decreasing oxygen concentrations (611 ± 176 and 228 ± 45%, respectively, at 0.5% O2). Elastin gene expression levels remained unaffected. Collagen synthesis and LH2 protein levels increased at oxygen concentrations of 2% and lower. Oxygen concentrations below 4% induce enhanced ECM production by human myofibroblasts. Implementation of these results in cardiovascular tissue engineering approaches enables in vitro control of tissue development.