bluuebunny/crossref_metadata_2025 huggingface dataset:
Decreased polarity and increased random motility in PtK1 epithelial cells correlate with inhibition of endosomal recycling
Authors: Prigozhina Natalie L. , Waterman-Storer Clare M.
Published: August 2006

Locomoting cells exhibit a constant retrograde flow of plasma membrane proteins from the leading edge towards the cell center, which, when coupled to substrate adhesion, may drive forward cell movement. Here, we aimed to test the hypothesis that, in epithelial cells, these plasma membrane components are delivered via a polarized endo/exocytotic cycle, and that their correct recycling is required for normal migration. To this end, we expressed in PtK1 cells cDNA constructs encoding GDP-restricted (S25N) and GTP-restricted (Q70L) mutants of Rab11b, a small GTPase that has been implicated in the late stage of recycling, where membrane components from the endosomal recycling compartment are transported back to the plasma membrane. Surprisingly, we found that transient expression of the Rab11b mutants in randomly migrating PtK1 cells in small cell islands caused altered cell morphology and actually increased the velocity of cell locomotion. Stable expression of either mutant protein also did not decrease cell migration velocity, but instead affected the directionality of migration in monolayer wound healing assays. We have also tested the effects of other Rab proteins, implicated in endocytic recycling, and discovered a clear correlation between the degree of recycling inhibition and the increase in non-directional cell motility.
Efficient nuclear export of p65-IκBα complexes requires 14-3-3 proteins
Authors: Aguilera Cristina , Fernández-Majada Vanessa , Inglés-Esteve Julia , Rodilla Verónica , Bigas Anna , Espinosa Lluís
Published: August 2006

IκB are responsible for maintaining p65 in the cytoplasm under non-stimulating conditions and promoting the active export of p65 from the nucleus following NFκB activation to terminate the signal. We now show that 14-3-3 proteins regulate the NFκB signaling pathway by physically interacting with p65 and IκBα proteins. We identify two functional 14-3-3 binding domains in the p65 protein involving residues 38-44 and 278-283, and map the interaction region of IκBα in residues 60-65. Mutation of these 14-3-3 binding domains in p65 or IκBα results in a predominantly nuclear distribution of both proteins. TNFα treatment promotes recruitment of 14-3-3 and IκBα to NFκB-dependent promoters and enhances the binding of 14-3-3 to p65. Disrupting 14-3-3 activity by transfection with a dominant-negative 14-3-3 leads to the accumulation of nuclear p65-IκBα complexes and the constitutive association of p65 with the chromatin. In this situation, NFκB-dependent genes become unresponsive to TNFα stimulation. Together our results indicate that 14-3-3 proteins facilitate the nuclear export of IκBα-p65 complexes and are required for the appropriate regulation of NFκB signaling.
cAMP synthesis and degradation by phagosomes regulate actin assembly and fusion events: consequences for mycobacteria
Authors: Kalamidas Stefanos A. , Kuehnel Mark P. , Peyron Pascale , Rybin Vladimir , Rauch Susanne , Kotoulas Othon B. , Houslay Miles , Hemmings Brian A. , Gutierrez Maximiliano G. , Anes Elsa , Griffiths Gareth
Published: August 2006

We showed recently that actin assembly by phagosomal membranes facilitates fusion with late endocytic organelles in macrophages. Moreover, lipids that induced phagosomal actin also stimulated this fusion process. In macrophages infected with pathogenic mycobacteria actin-stimulatory lipids led to an increase in pathogen destruction, whereas inhibitors facilitated their growth. A model was proposed whereby phagosomal membrane actin assembly provides tracks for lysosomes to move towards phagosomes, thereby facilitating fusion. Here, we investigated how cAMP affected phagosomal actin assembly in vitro, and phagosomal actin, acidification and late fusion events in J774 macrophages. Latex bead phagosomes are shown to possess adenylyl cyclase activity, which synthesizes cAMP, and phosphodiesterase activity, which degrades cAMP. The system is regulated by protein kinase A (PKA). Increasing cAMP levels inhibited, whereas decreasing cAMP levels stimulated, actin assembly in vitro and within cells. Increasing cAMP levels also inhibited phagosome-lysosome fusion and acidification in cells, whereas reducing cAMP had the opposite effect. High cAMP levels induced an increase in intraphagosomal growth in macrophages of both the non-pathogenic Mycobacterium smegmatis and the pathogenic Mycobacterium tuberculosis, whereas low cAMP levels or inhibition of PKA correlated with increased bacterial destruction. We argue that the phagosome cAMP-PKA system behaves as a molecular switch that regulates phagosome actin and maturation in macrophages.
Ubiquitin protein ligase Nedd4 binds to connexin43 by a phosphorylation-modulated process
Authors: Leykauf Kerstin , Salek Mojibrahman , Bomke Jörg , Frech Matthias , Lehmann Wolf-Dieter , Dürst Matthias , Alonso Angel
Published: August 2006

Connexin43 is degraded by the proteasomal as well as the lysosomal pathway with ubiquitin playing a role in both degradation pathways. So far, no ubiquitin protein ligase has been identified for any of the connexins. By using pull-down assays, here we show binding of a ubiquitin protein ligase, Nedd4, to the C-terminus of connexin43. This observation was confirmed in vivo by coimmunoprecipitation and immunofluorescence, showing colocalization of Nedd4 and connexin43. Binding of Nedd4 to its interaction partners is generally carried out by its WW domains. Our results indicate that the interaction with connexin43 occurs through all three WW domains of Nedd4. Furthermore, whereas WW1 and WW2 domains mainly interact with the unphosphorylated form of connexin43, WW3 binds phosphorylated and unphosphorylated forms equally. In addition, using the surface plasmon resonance approach we show that only the WW2 domain binds to the PY motif located at the C-terminus of connexin43. Suppression of Nedd4 expression with siRNA resulted in an accumulation of gap junction plaques at the plasma membrane, suggesting an involvement of the ubiquitin protein ligase Nedd4 in gap junction internalization.
Noise, Stress and Annoyance
Authors: Rylander Ragnar
Published: August 2006

The effects of sound on man are reviewed with emphasis on the physiological reaction mechanisms and the ultimate stress reaction. It is seen that energy related noise levels are poor predictors for the reactions in man as noise is always interpreted in the central nervous system, generating secondary and tertiary reactions that are not controlled by the brain cortex. The stimulation of these reaction pathways in acute situations lead to involuntary reflexes and feelings of fright and despair. In chronic exposure situations a give-up stage may develop with reduced corporal and mental functions. In the acoustical panorama peak level noises usually cause the most pronounced effects as they stimulate reactions of fear and flight. The practical consequences of these reaction patterns in terms of prevention are discussed.
Primal-Dual Algorithms for Deterministic Inventory Problems
Authors: Levi Retsef , Roundy Robin O. , Shmoys David B.
Published: August 2006

We consider several classical models in deterministic inventory theory: the single-item lot-sizing problem, the joint replenishment problem, and the multistage assembly problem. These inventory models have been studied extensively, and play a fundamental role in broader planning issues, such as the management of supply chains. For each of these problems, we wish to balance the cost of maintaining surplus inventory for future demand against the cost of replenishing inventory more frequently. For example, in the joint replenishment problem, demand for several commodities is specified over a discrete finite planning horizon, the cost of maintaining inventory is linear in the number of units held, but the cost incurred for ordering a commodity is independent of the size of the order; furthermore, there is an additional fixed cost incurred each time a nonempty subset of commodities is ordered. The goal is to find a policy that satisfies all demands on time and minimizes the overall holding and ordering cost.

We shall give a novel primal-dual framework for designing algorithms for these models that significantly improve known results in several ways: the performance guarantees for the quality of the solutions improve on or match previously known results; the performance guarantees hold under much more general assumptions about the structure of the costs, and the algorithms and their analysis are significantly simpler than previous known results. Finally, our primal-dual framework departs from the structure of previously studied primal-dual approximation algorithms in significant ways, and we believe that our approach may find applications in other settings. More specifically, we provide 2-approximation algorithms for the joint replenishment problem and for the assembly problem, and solve the single-item lot-sizing problem to optimality. The results for the joint replenishment and the lot-sizing problems also hold for their generalizations with back orders allowed. As a byproduct of our work, we prove known and new upper bounds on the integrality gap of some linear-programming (LP) relaxations of the abovementioned problems.
Optimal Control and Hedging of Operations in the Presence of Financial Markets
Authors: Caldentey René , Haugh Martin
Published: August 2006

We consider the problem of dynamically hedging the profits of a corporation when these profits are correlated with returns in the financial markets. In particular, we consider the general problem of simultaneously optimizing over both the operating policy and the hedging strategy of the corporation. We discuss how different informational assumptions give rise to different types of hedging and solution techniques. Finally, we solve some problems commonly encountered in operations management to demonstrate the methodology.
Properly Maximal Points in Product Spaces
Authors: Guerraggio Angelo , Luc Dinh The
Published: August 2006

We study maximal points in a locally convex space partially ordered by a convex cone with a bounded base. Properly maximal points are defined and compared with other concepts of efficiency. Existence and density theorems are given which unify and generalize several results known in recent literature. Particular attention is paid on properly maximal points in a product space which has an interesting application in obtaining a multiplier rule for convex set-valued problems in a general setting.
The Fluid Limit of an Overloaded Processor Sharing Queue
Authors: Puha Amber L. , Stolyar Alexander L. , Williams Ruth J.
Published: August 2006

This paper primarily concerns strictly supercritical fluid models, which arise as functional law of large numbers approximations for overloaded processor sharing queues. Analogous results for critical fluid models associated with heavily loaded processor sharing queues are contained in Gromoll et al. (2002) and Puha and Williams (2004). An important distinction between critical and strictly supercritical fluid models is that the total mass for a solution that starts from zero grows with time for the latter, but it is identically equal to zero for the former. For strictly supercritical fluid models, this paper contains descriptions of each of the following: the distribution of the mass as it builds up from zero, the set of stationary solutions, and the limiting behavior of an arbitrary solution as time tends to infinity. In addition, a fluid limit result is proved that justifies strictly supercritical fluid models as first order approximations to overloaded processor sharing queues.
Permuted Standardized Time Series for Steady-State Simulations
Authors: Calvin James M. , Nakayama Marvin K.
Published: August 2006

We describe an extension procedure for constructing new standardized time series procedures from existing ones. The approach is based on averaging over sample paths obtained by permuting path segments. Analytical and empirical results indicate that permuting improves standardized time series methods. We compare permuting to an alternative extension procedure known as batching. We demonstrate the permuting method by applying it to estimators based on the maximum and the area of a normalized path.
Evolutionary Stability for Large Populations and Backward Induction
Authors: Gorodeisky Ziv
Published: August 2006

It has been shown (Hart 2002) that the backward induction (or subgame-perfect) equilibrium of a perfect information game is the unique stable outcome for dynamic models consisting of selection and mutation, when the mutation rate is low and the populations are large, under the assumption that the expected number of mutations per generation is bounded away from zero.

Here it is shown that one can dispense with this last condition. In particular, it follows that the backward induction equilibrium is evolutionarily stable for large populations.
Optimization of Convex Risk Functions
Authors: Ruszczyński Andrzej , Shapiro Alexander
Published: August 2006

We consider optimization problems involving convex risk functions. By employing techniques of convex analysis and optimization theory in vector spaces of measurable functions, we develop new representation theorems for risk models, and optimality and duality theory for problems with convex risk functions.
Core Stability of Minimum Coloring Games
Authors: Bietenhader Thomas , Okamoto Yoshio
Published: August 2006

In cooperative game theory, a characterization of games with stable cores is known as one of the most notorious open problems. We study this problem for a special case of the minimum coloring games, introduced by Deng et al. (1999), which arise from a cost allocation problem when the players are involved in conflict. In this paper, we show that the minimum coloring game on a perfect graph has a stable core if and only if every vertex of the graph belongs to a maximum clique. We also consider the problem on the core largeness, the extendability, and the exactness of minimum coloring games. As a consequence, we show that it is coNP-complete to decide whether a given game has a large core, is extendable, or is exact.
Job Shop Scheduling with Unit Processing Times
Authors: Bansal Nikhil , Kimbrel Tracy , Sviridenko Maxim
Published: August 2006

We consider randomized algorithms for the preemptive job shop problem, or equivalently, the case in which all operations have unit length. We give an α-approximation for the case of two machines where α < 1.45, an improved approximation ratio of O(log m/log log m) for an arbitrary number m of machines, and the first (2 + ε)-approximation for a constant number of machines. The first result is via an approximation algorithm for a string matching problem that is of independent interest.
On the Integrality Ratio for the Asymmetric Traveling Salesman Problem
Authors: Charikar Moses , Goemans Michel X. , Karloff Howard
Published: August 2006

We improve the lower bound on the integrality ratio of the Held-Karp bound for asymmetric TSP with triangle inequality from 4/3 to 2.
The Hamilton Apportionment Method Is Between the Adams Method and the Jefferson Method
Authors: Lauwers Luc , Puyenbroeck Tom Van
Published: August 2006

The Adams apportionment method is the only divisor method that consistently favors small districts relative to the Hamilton method. The Jefferson method is the only divisor method that favors large districts relative to the Hamilton method. These statements hold for the Balinski and Young (1978) interpretation of “favoring small/large districts,” and for the partial “majorization ranking” introduced by Marshall et al. (2002). As such, Hamilton is positioned in between Adams and Jefferson.
A Linearly Convergent Dual-Based Gradient Projection Algorithm for Quadratically Constrained Convex Minimization
Authors: Beck Amir , Teboulle Marc
Published: August 2006

This paper presents a new dual formulation for quadratically constrained convex programs. The special structure of the derived dual problem allows us to apply the gradient projection algorithm to produce a simple explicit method involving only elementary vector-matrix operations, proven to converge at a linear rate.
Simulated Annealing for Convex Optimization
Authors: Kalai Adam Tauman , Vempala Santosh
Published: August 2006

We apply the method known as simulated annealing to the following problem in convex optimization: Minimize a linear function over an arbitrary convex set, where the convex set is specified only by a membership oracle. Using distributions from the Boltzmann-Gibbs family leads to an algorithm that needs only O*(√n) phases for instances in ℝn. This gives an optimization algorithm that makes O*(n4.5) calls to the membership oracle, in the worst case, compared to the previous best guarantee of O*(n5).

The benefits of using annealing here are surprising because such problems have no local minima that are not also global minima. Hence, we conclude that one of the advantages of simulated annealing, in addition to avoiding poor local minima, is that in these problems it converges faster to the minima that it finds. We also give a proof that under certain general conditions, the Boltzmann-Gibbs distributions are optimal for annealing on these convex problems.
Optimal Control of a High-Volume Assemble-to-Order System
Authors: Plambeck Erica L. , Ward Amy R.
Published: August 2006

We consider an assemble-to-order system with a high volume of prospective customers arriving per unit time. Our objective is to maximize expected infinite-horizon discounted profit by choosing product prices, component production capacities, and a dynamic policy for sequencing customer orders for assembly. We prove that a myopic discrete-review sequencing policy, which allocates scarce components among orders for different products to minimize instantaneous physical and financial holding costs, is asymptotically optimal. Furthermore, we prove that optimal prices and production capacity nearly balance the supply and demand for components (i.e., it is economically optimal to operate the system in heavy traffic), so system performance is characterized by a diffusion approximation. The diffusion approximation exhibits state-space collapse: Its dimension equals the number of components (rather than the number of components plus the number of products). These results complement the existing assemble-to-order literature, which focuses on managing component inventory and assumes FIFO sequencing of orders for assembly.
The Value of Markov Chain Games with Lack of Information on One Side
Authors: Renault Jérôme
Published: August 2006

We consider a two-player zero-sum game, given by a Markov chain over a finite set of states and a family of matrix games indexed by states. The sequence of states follows the Markov chain. At the beginning of each stage, only Player 1 is informed of the current state, then the corresponding matrix game is played, and the actions chosen are observed by both players before proceeding to the next stage. We call such a game a Markov chain game with lack of information on one side. This model generalizes the model of Aumann and Maschler of zero-sum repeated games with lack of information on one side (which corresponds to the case where the transition matrix of the Markov chain is the identity matrix). We generalize the proof of Aumann and Maschler and, from the definition and the study of appropriate nonrevealing auxiliary games with infinitely many stages, show the existence of the uniform value. An important difference with Aumann and Maschler's model is that here the notions for Player 1 of using the information and revealing a relevant information are distinct.
Directional Stability Theorem and Directional Metric Regularity
Authors: Arutyunov Aram V. , Izmailov Alexey F.
Published: August 2006

We develop a new regularity concept, unifying metric regularity, Robinson’s constraint qualification, and directional regularity. We present the directional stability theorem and the related concept of directional metric regularity. On one hand, our directional stability theorem immediately implies Robinson’s stability theorem [Arutyunov, A. V. 2005. Covering of nonlinear maps on cone in neighborhood of abnormal point. Math. Notes 77 447–460.] as a particular case, while on the other hand, our theorem easily implies various stability results under the directional regularity condition, widely used in sensitivity analysis. Some applications of this kind are also presented.
Conditional Risk Mappings
Authors: Ruszczyński Andrzej , Shapiro Alexander
Published: August 2006

We introduce an axiomatic definition of a conditional convex risk mapping and we derive its properties. In particular, we prove a representation theorem for conditional risk mappings in terms of conditional expectations. We also develop dynamic programming relations for multistage optimization problems involving conditional risk mappings.
Regret Minimization Under Partial Monitoring
Authors: Cesa-Bianchi Nicolò , Lugosi Gábor , Stoltz Gilles
Published: August 2006

We consider repeated games in which the player, instead of observing the action chosen by the opponent in each game round, receives a feedback generated by the combined choice of the two players. We study Hannan-consistent players for these games, that is, randomized playing strategies whose per-round regret vanishes with probability one as the number n of game rounds goes to infinity. We prove a general lower bound of Ω(n−1/3) for the convergence rate of the regret, and exhibit a specific strategy that attains this rate for any game for which a Hannan-consistent player exists.
Many-to-One Stable Matching: Geometry and Fairness
Authors: Sethuraman Jay , Teo Chung-Piaw , Qian Liwen
Published: August 2006

Baïou and Balinski characterized the stable admissions polytope using a system of linear inequalities. The structure of feasible solutions to this system of inequalities—fractional stable matchings—is the focus of this paper. The main result associates a geometric structure with each fractional stable matching. This insight appears to be interesting in its own right, and can be viewed as a generalization of the lattice structure (for integral stable matchings) to fractional stable matchings. In addition to obtaining simple proofs of many known results, the geometric structure is used to prove the following two results: First, it is shown that assigning each agent their “median” choice among all stable partners results in a stable matching, which can be viewed as a “fair” compromise; second, sufficient conditions are identified under which stable matchings exist in a problem with externalities, in particular, in the stable matching problem with couples.
A Cost-Shaping Linear Program for Average-Cost Approximate Dynamic Programming with Performance Guarantees
Authors: de Farias Daniela Pucci , Van Roy Benjamin
Published: August 2006

We introduce a new algorithm based on linear programming for optimization of average-cost Markov decision processes (MDPs). The algorithm approximates the differential cost function of a perturbed MDP via a linear combination of basis functions. We establish a bound on the performance of the resulting policy that scales gracefully with the number of states without imposing the strong Lyapunov condition required by its counterpart in de Farias and Van Roy [de Farias, D. P., B. Van Roy. 2003. The linear programming approach to approximate dynamic programming. Oper. Res. 51(6) 850–865]. We investigate implications of this result in the context of a queueing control problem.
Nonparametric Estimation of Market Distribution Functions in Electricity Pool Markets
Authors: Pritchard Geoffrey , Zakeri Golbon , Philpott Andrew
Published: August 2006

The market distribution function is a probabilistic device that can be used to model the randomness in dispatch and clearing price that generators in electricity-pool markets must take account of when submitting offers. We discuss techniques for estimating the market distribution function, and ways of measuring the quality of these estimators, using both classical statistical approaches and an expected-foregone-revenue approach.
Excludability and Bounded Computational Capacity
Authors: Lehrer Ehud , Solan Eilon
Published: August 2006

We study the notion of excludability in repeated games with vector payoffs, when one of the players is restricted to strategies with bounded computational capacity. We show that a closed set is excludable by Player 2 when Player 1 is restricted to using only bounded-recall strategies if and only if it does not contain a convex approachable set. We provide partial results when Player 1 is restricted to using strategies that can be implemented by automata.
An examination of the multidimensionality of supervisor and subordinate perceptions of leader‐member exchange
Authors: Greguras Gary J. , Ford John M.
Published: August 2006

Research on leader‐member exchange (LMX) theory typically has measured LMX in a unidimensional manner and has neglected supervisor perceptions of the LMX relationship. The present study developed and validated a multidimensional scale of supervisor LMX based on Liden and Maslyn's (1998) multidimensional subordinate LMX scale. Confirmatory factor analyses supported a multidimensional factor structure for both supervisor and subordinate LMX scales with four distinct dimensions: affect, loyalty, contribution, and professional respect. Results further indicated that these dimensions differentially predicted various criteria indicating that different aspects of the LMX relationship are of greater or lesser importance depending upon the criterion of interest. Additionally, results indicated that multidimensional LMX scales measured from both supervisor and subordinate perspectives predict important individual job attitudes and behaviours above scales that are either unidimensional or measured from just one perspective.
Testing causal models of job characteristics and employee well‐being: A replication study using cross‐lagged structural equation modelling
Authors: ter Doest Laura , De Jonge Jan
Published: August 2006

This study re‐evaluated causal relationships between job characteristics (demands, autonomy, social support) and employee well‐being (job satisfaction, emotional exhaustion) in a methodological replication of De Jonge et al. 's (2001) two‐wave panel study. The principal difference was the 2‐year time lag between measurements in this study versus a 1‐year time lag in the original study. Three competing causal models were compared: regular causation (job characteristics influence well‐being); reverse causation (well‐being influences job characteristics); and reciprocal causation (combining regular and reverse causation). As in the original study, regular causation offered the best account. Regarding specific longitudinal paths there were some between‐study differences, which are considered in relation to exposure‐time models of stressor‐strain relations.
On the scrap‐heap at 45: The human impact of mature‐aged unemployment
Authors: Ranzijn Rob , Carson Ed , Winefield A. H. , Price Debbie
Published: August 2006

This paper reports on a qualitative study conducted in Adelaide, South Australia into the impact of mature‐aged unemployment and under‐employment on the individual. Data were collected by means of six individual and group interviews with a total of 27 participants (17 men and 10 women). The participants were asked about the impact on their quality of life, their expectations for the future and their short‐term and long‐term financial situation. The results suggest that there is a substantial ‘lost generation’ of mature‐aged unemployed people who are characterized by shrinking horizons and impaired quality of life. The participants expressed frustration at being unable to contribute to society and support their own adult children. Inability to use their skills and talents, with consequent skill depreciation, can lead to what we label the ‘peg‐down phenomenon’, an intermediate step between becoming unemployed and entering the ranks of the discouraged job‐seekers that ultimately leads to a premature exit from the workforce. This cohort is different from other age groups of unemployed people because of the unique developmental characteristics of middle‐aged people, compounded by financial and caring demands from both the younger and older generations. The paper concludes with policy recommendations, including expanding social inclusion policies to address the needs of this cohort and early intervention with more focused job‐specific training.
Promoting innovation: A change study
Authors: Axtell Carolyn , Holman David , Wall Toby
Published: August 2006

This paper considers how employee innovation develops during the course of introducing team‐working for production‐related staff. Longitudinal analysis revealed that different predictors were active at different phases. At first, changes in idea implementation were related to changes in management support. Subsequently, changes in suggestion making were associated with changes in job control and changes in idea implementation were linked to changes in team support for innovation. Results are consistent with the developmental notion that, whilst external support is an important predictor of innovation initially, structural job changes and local regulation are more important later.
Reproducing gender inequalities? A critique of realist assumptions underpinning personnel selection research and practice
Authors: Dick Penny , Nadin Sara
Published: August 2006

Occupational discrimination and segregation along gendered lines continue to be seen as problematic throughout the UK and the USA. Women continue to be attracted to occupations that are considered to be women's work, such as clerical, secretarial and personal service work, and inequalities persist even when women enter traditional male domains such as management. Work psychology's chief, though indirect, contribution to this field has been through personnel selection research, where methods aimed at helping organizations to make more fair and unbiased selection decisions have been carefully examined. Our aim in this paper is to argue that, on their own, such methods can make very little difference to the position of women (and other minorities) in work organizations. The processes that are fundamental to organizational attraction and adjustment cannot, we contend, be understood adequately through reductionist approaches that treat organizational and individual characteristics as context independent realities. Drawing on critical management research and using the specific example of police work, we argue that work roles and work identities can be more fruitfully understood as social constructions that, whendeconstructed, illuminate more powerfully how processes that lead to the relative subordination of women (and other groups) are both reproduced and challenged.
Comparing the validity of structured interviews for managerial‐level employees: Should we look to the past or focus on the future?
Authors: Krajewski Henryk T. , Goffin Richard D. , McCarthy Julie M. , Rothstein Mitchell G. , Johnston Norman
Published: August 2006

The current research investigated questions that persist regarding the criterion‐related and construct validity of situational (SI) versus past‐behaviour (PBI) structured interview formats in predicting the job performance of managers. Analyses of data collected from 157 applicants to managerial positions showed that the PBI format significantly predicted job performance ratings (r = .32, p <.01), whereas the SI format did not (r = .09, ns). Investigation of potential construct differences between the SI and PBI formats showed that the PBI was more highly related to manager‐relevant cognitive ability measures, assessment centre exercises and personality traits, as compared with the SI. Such differences help to explain the predictive validity differences between the SI and PBI observed in current and previous research.
The psychodynamic perspective in organizational research: Making sense of the dynamics of direction setting in emergent collaborative processes
Authors: Prins Silvia
Published: August 2006

This paper demonstrates how the psychodynamic perspective can contribute to the study of organizing processes. Research from this perspective provides a complementary insight in what actually happens in an unfolding collaborative process, both on the manifest and latent level, and how subjectivity is expressed in the organizing process. First, the paper addresses the specific nature and challenges of ‘multiparty collaboration’. Then it describes how the psychodynamic approach can be used in organizational research and the kind of theory it generates. The author presents a case study in the domain of foster care, where five independent organizations tried to develop a scenario for future collaboration. The case analysis focuses on three critical issues with which the participants and consultants were struggling. It discusses how the dynamics that emerged around those issues set the direction of the process. The paper concludes with the benefits of using a psychodynamic perspective in organizational research. Its main contribution is a better understanding of the paradox between the intention and societal necessity for creative collaboration, and the emotional and defensive responses when participants are confronted with the tensions of collaborative work.
Constructing enterprise resource planning: A thoroughgoing interpretivist perspective on technological change
Authors: Shepherd Craig
Published: August 2006

Most perspectives towards understanding technology treat it as having essential material properties that constrain some uses and enable others. In contrast, this paper argues for an understanding which treats constructions of the capabilities of technology as interpretatively flexible and grounded within specific contexts. The paper begins with a review of perspectives towards understanding technological change. Next, I provide an overview of the discourse analysis literature. This locates the form of discourse analysis used here, systematic constructionism, within this milieu. Then, I introduce enterprise resource planning (ERP) systems and evaluate the literature. This is followed by a description of the context in which an ERP system was introduced and the methods of data collection and analysis. The analysis elaborates how three interpretative repertoires used to justify the implementation of the ERP system were disrupted by counter‐constructions produced by individuals reciprocally positioned within them. Moving on, I discuss the contributions and limitations of this approach for understanding technological change, before reflecting on how my commitments affect the data presented here and my ability to contribute to debates on technology. Finally, I propose there is a need for further studies that focus on unravelling the rhetoric surrounding technological change.
Neglected perspectives in work and organizational psychology
Authors: Symon Gillian , Cassell Catherine
Published: August 2006

In this editorial we suggest that work and organizational psychology has tended to overlook the insights to be gained from ‘alternative’ perspectives such as interpretivism, critical theory and postmodernism, in favour of a focus on more normative and positivist studies of organizational life. While paradigmatic conformity is argued by some to have the benefit of providing a coherent knowledge base, we argue that it may also lead to an overly restrictive viewpoint and constrained practices. In any case, such a focus may be partly a default option rather than a conscious choice, fostered by assumptions of what constitutes ‘good’ research which may not be appropriate to (and even discriminate against) other perspectives. As a consequence, this special section aims to illustrate the insights to be gained from adopting such ‘alternative’ perspectives on topics of contemporary interest to work and organizational psychologists, such as retention of women in the workforce, collaborative (cross‐agency) work, advanced technological change and stress at work.
The transition to motherhood in an organizational context: An interpretative phenomenological analysis
Authors: Millward Lynne J.
Published: August 2006

Most of the extant literature on maternity issues is survey based, primarily concerned with identifying the predictors of return to work. The current study aims instead to understand experiences of maternity leaveper se. Of the 10 women interviewed during pregnancy, 8 women were followed through to their return to work. Their interviews were analysed using interpretative phenomenological analysis to identify transitional themes. Findings are discussed in terms of two master themes: changes of identity (involving feelings of gradual invisibility as a valued employee, acquisition of a ‘mother’ identity creating return dilemmas and efforts to revalidate oneself upon re‐entry as both a valued employee and a mother); and changed psychological contracts (pertaining to the fulfilment of mutual expectations). Overall, women appeared to struggle subjectively with prevailing their rights, needs and concerns as mothers while simultaneously also maintaining their identity as valued and functional members of the organization. The findings can be conceptualized within existing theoretical frameworks (e.g. Psychological Contract Theory) and to this extent it is possible to draw out implications for a more effective management of the transition process from pregnancy to return to work.
Quantification by Liquid Chromatography Tandem Mass Spectrometry of Mycophenolic Acid and Its Phenol and Acyl Glucuronide Metabolites
Authors: Brandhorst Gunnar , Streit Frank , Goetze Sandra , Oellerich Michael , Armstrong Victor William
Published: August 2006

Background: We developed and validated a rapid and reliable liquid chromatography–tandem mass spectrometry (LC-MS/MS) procedure for the quantification of mycophenolic acid (MPA) and its phenol glucuronide (MPAG) and acyl glucuronide (AcMPAG) metabolites.

Methods: We performed protein precipitation on all samples (calibrators, quality controls, and patient samples) and then subjected them to online solid-phase extraction followed by reversed-phase liquid chromatography for 4.0 min. The carboxybutoxy ether of MPA (MPAC) was used as the internal calibrator. The separated compounds (MPA, MPAG, AcMPAG, and MPAC) were detected by electrospray ionization-coupled MS/MS. We compared LC-MS/MS results with results for the same samples obtained with a validated HPLC procedure with an ultraviolet detector.

Results: Comparison with the validated HPLC-ultraviolet procedure demonstrated good agreement. The Passing–Bablok regression was y = 0.968x − 0.058 for MPA, y = 1.08x − 1.697 for MPAG, and y = 0.952x + 0.076 for AcMPAG. Assay imprecision showed a CV <10% at 3 concentrations for each compound. The lower limit of quantification was 0.1 mg/L for MPA, 1.0 mg/L for MPAG, and 0.05 mg/L for AcMPAG. The mean analytical recovery was 90%–110%. The assay was linear from 0.1 to 50 mg/L for MPA (r = 0.9987), from 1 to 500 mg/L for MPAG (r = 0.9999), and from 0.05 to 10 mg/L for AcMPAG (r = 0.9988). Quantification of the compounds was not affected by in-source fragmentation or ion suppression.

Conclusion: The LC-MS/MS assay described here is valid and reliable for the quantification of total MPA, MPAG, and AcMPAG in serum.
Evaluating Methods for Water Vapor Transmission of Moisture Vapor Suppression Coatings on Concrete
Authors: King MB , Kanare H
Published: August 2006

Moisture vapor suppression coatings are used on millions of square feet of concrete floor slabs to remediate distress of moisture-sensitive floor coverings. We evaluated the suitability of ASTM E 96 and ASTM D 1653 for assessing performance of these coatings. ASTM E 96 can take several months, whereas free films can be evaluated using D 1653 in one to two weeks. Both methods were in close agreement for 100 % solids epoxy coatings but differ considerably for water-based coatings. Several types of coatings became severely distorted during D 1653 testing and could not provide useful results, including cementitious and polymer latexes and urethanes. Repeatability for coated and uncoated concrete specimens using ASTM E 96 was comparable to published precision data for other materials. The authors recommend that water vapor transmission testing of concrete and coated concrete specimens be included in the scope of ASTM E 96.
Geometry and Data Reduction Recommendations for a Standardized End Notched Flexure Test for Unidirectional Composites
Authors: Davidson BD , Sun X
Published: August 2006

Recommendations are made for choosing a test geometry and data reduction method for a standardized end-notched flexure test for unidirectional fibrous laminated polymeric composites with glass or graphite reinforcements. To this end, the accuracies of a variety of commonly used data reduction methods are evaluated over a range of geometries. This is done using a combination of numerical and experimental approaches. It is determined that the compliance calibration method of data reduction, with an associated expression for compliance, C, of the form C=A+ma3, provides the best combination of accuracy and usability of all those data reduction methods considered. Here, A and m are curve fitting parameters and a is the crack length, and the expression for compliance is obtained prior to the fracture test by a series of compliance tests at different crack lengths to a load approximately equal to 50 % of that required for fracture. When this approach is used along with the associated recommendations for slenderness ratio of the specimen and roller diameters of the fixture, it is shown that the toughness that is extracted from the test will be within 3 % of its true value for materials with coefficients of friction, μ, along the interface containing a preimplanted insert of 0.0≤μ≤0.5. All materials for which experimental data are available show μ to be within this range. As such, this compliance calibration method is recommended as the sole data reduction method for the standardized test.
Replacement of the Final Time of Setting Maximum with an Initial Time of Setting Maximum as measured with the Gillmore Needles in ASTM C 91, C 1328, and C 1329
Authors: Conway JT
Published: August 2006

ASTM Subcommittee C01.11 on Masonry Cement, established a task group on methods of test which determined whether the final time of setting maximum limit could be replaced with an initial time of setting maximum limit. A review was conducted of 52 Cement and Concrete Reference Laboratory proficiency samples (spanning 26 years) and data from the Portland Cement Association Masonry Cement Survey. Findings indicate a very reliable and simple linear relationship exists between masonry cement initial and final Gillmore time of setting. Data is presented which resulted in a specification change to ASTM C 91, ASTM C 1328, and ASTM C 1329 in 2005.
Statistical Correlations Between Seismic Wave Velocities and SPT Blow Counts and the Relative Density of Soils
Authors: Ulugergerli EU , Uyanik O
Published: August 2006

The relation between seismic P and S-wave velocities, standard penetration test blow counts (SPT-N) and relative density are the subject of our research. We focused especially on variations of SPT-N versus seismic velocities and relative density versus seismic velocities. Contrary to the traditional approach, the scattered nature of the graphs led us to define the empirical relations as upper and lower bounds instead of single average curves. The values, calculated from the upper and lower limits, have large ranges and, therefore, span whole observable values of the site and geological unit. The wideness of the range between the upper and lower limit recommends that if a geotechnical parameter is required for the assessment of the soil condition; direct gathering from the field or core sample must be employed for a realistic evaluation.
Accelerated Diffusion Test on the Intact Rock Mass
Authors: Hanumantha Rao B , Dalinaidu A , Singh DN
Published: August 2006

Contaminant transport through intact rock mass is predominantly diffusive and its modeling using the conventional laboratory tests is extremely time consuming. In addition, maintaining constant ambient conditions over a long duration is difficult and practically impossible. This necessitates modification of the conventional laboratory diffusion experiments so that the diffusion of ions through the intact rock mass is accelerated. To achieve this, researchers have employed an electric field across the samples of concrete and clays. However, the influence of the applied electric field on diffusion characteristics of the intact rock mass has not been studied in detail. With this in view, diffusion tests were conducted on the samples of chalk and sandstone by applying electric fields of different strength. Details of the testing methodology are presented in this paper. Efforts were also made to study the influence of the applied electric field on diffusion characteristics of these rocks.
Petrophysical Measurements From Drill Cuttings: An Added Value for the Reservoir Characterization Process
Authors: Egermann P. , Doerler N. , Fleury M. , Behot J. , Deflandre F. , Lenormand R.
Published: August 2006

Permeability and porosity are necessary for reservoir characterization, and cuttings can provide quick information using dedicated measurement techniques. In this paper, we present the first applications of these techniques on real reservoir characterization cases and the comparisons with logs and core data.

The method of permeability measurement from cuttings is based on a pressure pulse applied to a cell filled initially with cuttings saturated with viscous fluid in the presence of trapped gas. The permeability is derived from the transient response of the oil invasion into the cuttings by using a numerical approximation of a mathematical model. The porosity of dry drill cuttings is measured using the routine helium technique. These methods were tested and validated by using various samples of crushed rock of known permeability and porosity. Both measurement techniques are fast, require light conditioning, are applicable over a large range of permeability, and need only 1 mL of sieved rock to be carried out.

In this paper, we present a field application of an integrated drill cuttings measurement program [permeability, porosity, nuclear magnetic resonance (NMR) T2 distribution] on a carbonate reservoir. Various drilling conditions [including water-based mud (WBM) and oil-based mud (OBM)] and lithologies have been investigated to develop the different techniques that are presented in the paper. The question of whether measurements on cuttings are representative of the native reservoir is of primary importance and was checked by comparing the consistency of the porosity measurements obtained from cuttings with other data (cores or logs). The overall results demonstrate the added value of k and ϕ measurements from cuttings in addition to the data that are commonly collected.