bluuebunny/crossref_metadata_2025 huggingface dataset:
Managers' upward influence tactic strategies: the role of manager personality and supervisor leadership style
Authors: Cable Daniel M. , Judge Timothy A.
Published: February 2003

Why do managers employ certain tactics when they try to influence others? This study proposes and tests theoretical linkages between the five‐factor model of personality and managers' upward influence tactic strategies. Longitudinal data from 189 managers at 140 different organizations confirmed that managers scoring high on extraversion were more likely to use inspirational appeal and ingratiation; those scoring high on openness were less likely to use coalitions; those scoring high on emotional stability were more likely to use rational persuasion and less likely to use inspirational appeal; those scoring high on agreeableness were less likely to use legitimization or pressure; and those scoring high on conscientiousness were more likely to use rational appeal. Results also confirmed that managers' upward influence tactic strategies depended on the leadership style of their target (their supervisor). Managers were more likely to use consultation and inspirational appeal tactics when their supervisor was a transformational leader, but were more likely to use exchange, coalition, legitimization, and pressure tactics when their supervisor displayed a laissez‐faire leadership style. Copyright © 2002 John Wiley & Sons, Ltd.
Does one good turn deserve another? coworker influences on employee citizenship
Authors: Bommer William H. , Miles Edward W. , Grover Steven L.
Published: February 2003

Social information processing and social learning theories were utilized to hypothesize that an employee's organizational citizenship behavior (OCB) is influenced by the collective OCB in one's workgroup. An aggregate measure of OCB was constructed based upon Podsakoff, MacKenzie, and Fetter's (1993) measures of Organ's (1988) typology of OCB, and the study was replicated using both supervisor and employee‐provided ratings of OCB. The sample for this study included 566 employees (488 for the supervisor‐rated analysis) from 56 workgroups in a manufacturing organization. The mean level of OCB for other members of one's workgroup explained significant variance in individual levels of OCB. We also found that this effect is moderated by the consistency of the display of the OCB within the workgroup. The consistency of OCB across coworkers was associated with more OCB by individuals and this effect was replicated across both supervisor and employee ratings. Explanations and uses for our findings are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Straining towards trust: some constraints essay on studying trust in organizations
Authors: Fichman Mark
Published: February 2003

Trust is of great interest in organizational research and the social sciences. It is argued here that any theory of trust ought to treat a set of observed empirical regularities as constraints. A constraint on a theory is either an assumption made in constructing the theory (e.g., we assume people have a tendency to be fair in their dealings with others) or an explanandum (e.g., we must explain the tendency people have to be fair in their dealings with others) for which the theory must account. These constraints are best thought of in an evolutionary framework, with intellectual links to game theory, evolutionary biology and evolutionary psychology. In particular, (1) people are disposed towards fairness and reciprocity, they have (2) cognitive modules and (3) emotional dispositions which safeguard them against cheating and trust violation. Given these three constraints, any theory should consider the (4) evidence for cultural constraints on trust, trusting behavior and decisions. These constraints together point us towards an integrated ecology of trust where culture, individual dispositions and cognition jointly influence observed trusting behavior. Some work, particularly Gintis et al. (2002) on altruism, strong reciprocity and cooperation, suggests such an approach to studying trust. The purpose of this essay is to identify this work, organize it, and argue for its bearing on the study of trust and organizations. Copyright © 2003 John Wiley & Sons, Ltd.
Dynamic exercise imaging with an MR‐compatible stationary cycle within the general electric open magnet
Authors: Cheng Christopher P. , Schwandt Douglas F. , Topp Eric L. , Anderson James H. , Herfkens Robert J. , Taylor Charles A.
Published: February 2003

Many cases of muscular ischemia do not manifest without increased metabolic demand. Hence, diagnosis of intermittent claudication often requires inducing physiologic challenge, such as by exercise. Cine phase‐contrast MRI can concurrently acquire cross‐sectional vascular anatomy and through‐plane blood velocities, enabling blood flow rate quantification. An MR‐compatible stationary cycle was designed, constructed, and tested for flow quantification in large arteries during lower‐limb exercise in a General Electric Signa SP 0.5 T open magnet. The cycle demonstrated smooth cycling during image acquisition, has freewheeling capability, is adjustable for subject size and strength, and can quantify workload. A healthy 59‐year‐old male was imaged at the supraceliac and infrarenal levels of the abdominal aorta at rest and during exercise. An exercise workload of 47.9 W was achieved. His heart rate increased from 52 to 78 bpm, supraceliac flow increased from 1.7 to 3.7 L/min, and infrarenal flow increased from 0.4 to 3.2 L/min from rest to exercise. Magn Reson Med 49:581–585, 2003. © 2003 Wiley‐Liss, Inc.
Effects of hematocrit and oxygen saturation level on blood spin‐lattice relaxation
Authors: Silvennoinen M. Johanna , Kettunen Mikko I. , Kauppinen Risto A.
Published: February 2003

In the present study blood T1 was determined as a function of hematocrit and oxygen saturation. T1 showed a significant linear dependency on both of these parameters. In addition, oxygen dissolved in blood plasma in hyperoxygenated blood resulted in relaxation enhancement, comparable in size to that due to the change in oxygenation state of hemoglobin. As blood T1 is a key factor for quantification of flow with arterial spin labeling methods, the influence of T1 variation in the physiological range of hematocrit and oxygen saturation to flow determination is discussed. Magn Reson Med 49:568–571, 2003. © 2003 Wiley‐Liss, Inc.
Reduced k‐space encoding for dual‐contrast TrueFISP imaging
Authors: Merrifield Robert , Keegan Jennifer , Firmin David , Yang Guang‐Zhong
Published: February 2003

Dual‐contrast TrueFISP imaging relies on the use of two RF pulses with different RF flip‐angles for enhancing image contrast and performing automatic tissue classification based on multispectrum clustering. The original technique, however, involves an extended imaging time, which limits its clinical application. The purpose of this study is to compare the applicability of two reduced k‐space sampling techniques, reduced imaging using generalized series reconstruction (RIGR) and key‐hole imaging, for minimizing the imaging time required. The performance of both approaches was evaluated theoretically and practically using 3D cine datasets acquired from eight asymptomatic subjects. Magn Reson Med 49:595–598, 2003. © 2003 Wiley‐Liss, Inc.
Albumin‐binding MR blood pool agents as MRI contrast agents in an intracranial mouse glioma model
Authors: Adzamli Kofi , Yablonskiy Dmitriy A. , Chicoine Michael R. , Won Eun Kyung , Galen Karen P. , Zahner Michael C. , Woolsey Thomas A. , Ackerman Joseph J.H.
Published: February 2003

Intravenous MRI contrast agents are commonly used to improve the detection of intracranial tumors and other central nervous system (CNS) lesions for diagnosis and treatment planning. Two small‐molecule, albumin‐binding blood pool contrast agents (MP‐2269 and MS‐325) of potential clinical significance were evaluated at 1.5 Tesla in a mouse glioma model and compared with an extracellular contrast agent (OptiMARK). Tumor image contrast was significantly enhanced and long‐lived following administration of 30 μmole/kg of the blood pool agents: specifically, contrast enhancement peaked slowly at 25–30 min following administration, remained constant for >3 hr, and returned to baseline within 20 hr. Comparable but “transient” enhancement was achieved using 100 μmole/kg OptiMARK: specifically, contrast enhancement peaked rapidly at 2–5 min following administration and then declined over 40 min. The blood pool contrast agents demonstrated an approximately threefold increased dose‐effectiveness and a lengthened window of tumor contrast enhancement in comparison to commonly available extracellular contrast agents. This demonstrates the potential of alternative contrast‐enhanced (CE) MRI examination protocols for tumor detection. Magn Reson Med 49:586–590, 2003. © 2003 Wiley‐Liss, Inc.
Fast method for correcting image misregistration due to organ motion in time‐series MRI data
Authors: Gupta Sandeep N. , Solaiyappan Meiyappan , Beache Garth M. , Arai Andrew E. , Foo Thomas K.F.
Published: February 2003

Time‐series MRI data often suffers from image misalignment due to patient movement and respiratory and other physiologic motion during the acquisition process. It is necessary that this misalignment be corrected prior to any automated quantitative analysis. In this article a fast and automated technique for removing in‐plane misalignment from time‐series MRI data is presented. The method is computationally efficient, robust, and fine‐tuned for the clinical setting. The method was implemented and tested on data from 21 human subjects, including myocardial perfusion imaging, renal perfusion imaging, and blood‐oxygen level‐dependent cardiac T imaging. In these applications 10‐fold or better reduction in image misalignment is reported. The improvement after registration on representative time–intensity curves is shown. Although the method currently corrects translation motion using image center of mass, the mathematical framework of our approach may be extended to correct rotation and other higher‐order displacements. Magn Reson Med 49:506–514, 2003. © 2003 Wiley‐Liss, Inc.
Computing oxygen‐enhanced ventilation maps using correlation analysis
Authors: Mai Vu M. , Tutton Sean , Prasad Pottumarthi V. , Chen Qun , Li Wei , Chen Chi , Liu Benjamin , Polzin Jason , Kurucay Saban , Edelman Robert R.
Published: February 2003

Correlation maps of oxygen‐enhanced ventilation were obtained in nine healthy volunteers using complete and selected image series. The complete series included all images acquired with the subjects alternately inhaling room air and 100% oxygen. The selected series were the subsets of the complete series and included only co‐registered images that showed matched diaphragmatic position at maximal expiration. Cross‐correlation was computed between the time response function of each pixel and the input function representing the alternation between periods of room air and 100% oxygen inhalation. The confidence level for the correlation analysis was set to 0.01. Pulmonary parenchymal anatomy was consistently reproduced throughout the lung, even in anterior slices where published data have reported correlation problems. The overall average correlation coefficient was 0.66 ± 0.07 for the complete series and 0.75 ± 0.08 for the selected series. It was concluded that correlation analysis could be used to reconstruct qualitative oxygen‐enhanced ventilation maps. Magn Reson Med 49:591–594, 2003. © 2003 Wiley‐Liss, Inc.
Effects of equilibrium exchange on diffusion‐weighted NMR signals: The diffusigraphic “shutter‐speed”
Authors: Lee Jing‐Huei , Springer Charles S.
Published: February 2003

A general picture is presented of the implications for diffusion‐weighted NMR signals of the parsimonious two‐site‐exchange (2SX) paradigm. In particular, it is shown that the diffusigraphic “shutter‐speed,” τ−1 ≡ |q2(DA – DB)|, is a useful concept. The “wave‐number” q has its standard definition (given in the text), and DA and DB are the apparent diffusion coefficients (ADCs) of molecules in the two “sites,” A and B, if there is no exchange between them. At low gradient strengths (center of q‐space), τ−1 is less than rate constants for intercompartmental water molecule exchange in most tissue cases. Thus, the exchange reaction appears fast. However, q is increased during the course of most experiments and, as it is, the shutter‐speed becomes “faster” and the exchange reaction, the kinetics of which do not change, appears to slow down. This causes a multiexponential behavior in the diffusion‐weighting dimension, b, which also has its standard definition. This picture is found to be in substantial agreement with a number of different experimental observations. It is applied here to literature 1H2O data from a yeast cell suspension and from the human and the rat brain. Since the equilibrium transcytolemmal water exchange reaction appears to be in the fast‐exchange‐limit at small b, the initial slope represents the weighted‐average of the ADCs of intra‐ and extracellular water. Of course, in tissue the former is in the significant majority. Furthermore, a consideration of reasonable values for the other 2SX parameters suggests that, for resting brain tissue, the intracellular water ADC may be larger than the extracellular water ADC. There are some independent inferences of this, which would have ramifications for many applications of diffusion‐weighted MRI. Magn Reson Med 49:450–458, 2003. Published 2003 Wiley‐Liss, Inc.
Rapid combined T1 and T2 mapping using gradient recalled acquisition in the steady state
Authors: Deoni Sean C.L. , Rutt Brian K. , Peters Terry M.
Published: February 2003

A novel, fully 3D, high‐resolution T1 and T2 relaxation time mapping method is presented. The method is based on steady‐state imaging with T1 and T2 information derived from either spoiling or fully refocusing the transverse magnetization following each excitation pulse. T1 is extracted from a pair of spoiled gradient recalled echo (SPGR) images acquired at optimized flip angles. This T1 information is combined with two refocused steady‐state free precession (SSFP) images to determine T2. T1 and T2 accuracy was evaluated against inversion recovery (IR) and spin‐echo (SE) results, respectively. Error within the T1 and T2 maps, determined from both phantom and in vivo measurements, is approximately 7% for T1 between 300 and 2000 ms and 7% for T2 between 30 and 150 ms. The efficiency of the method, defined as the signal‐to‐noise ratio (SNR) of the final map per voxel volume per square root scan time, was evaluated against alternative mapping methods. With an efficiency of three times that of multipoint IR and three times that of multiecho SE, our combined approach represents the most efficient of those examined. Acquisition time for a whole brain T1 map (25 × 25 × 10 cm) is less than 8 min with 1 mm3 isotropic voxels. An additional 7 min is required for an identically sized T2 map and postprocessing time is less than 1 min on a 1 GHz PIII PC. The method therefore permits real‐time clinical acquisition and display of whole brain T1 and T2 maps for the first time. Magn Reson Med 49:515–526, 2003. © 2003 Wiley‐Liss, Inc.
A simple measure of flow disorder and wall shear stress in phase contrast MRI
Authors: Pipe James G.
Published: February 2003

A method for estimating the standard deviation of velocity within a voxel is proposed. This estimate is based on data collected using a phase‐contrast MRI technique. Simulations are presented to characterize the estimate and in vivo data are shown. Several different uses of the estimate are proposed, including obtaining a measure of wall shear stress, aiding in data combination from different phase‐contrast MRI datasets, and mitigation of flow void artifacts. Magn Reson Med 49:543–550, 2003. © 2003 Wiley‐Liss, Inc.
Autophosphorylation kinetics of protein kinases
Authors: WANG Zhi-Xin , WU Jia-Wei
Published: February 2003

Protein kinases play a central role in cellular signal transduction, by transmitting biochemical information between activated membrane-bound receptors and physiological target proteins. In addition to phosphorylating other proteins, almost all protein kinases catalyse autophosphorylation reactions (i.e. reactions in which the kinase serves as its own substrate). The autophosphorylation reactions can be intramolecular or intermolecular. In the present study, a detailed kinetic analysis of the intermolecular autophosphorylation reaction is presented. On the basis of the kinetic equations, a new procedure is developed to evaluate the kinetic parameters of the autophosphorylation reaction. This method was used to analyse the intermolecular autophosphorylation of an S6/H4 kinase from human placenta. At a fixed ATP concentration of 0.125mM, the apparent catalytic-centre activity (turnover number; kcat) and apparent Michaelis—Menten constant (Km) for the autophosphorylation reaction were determined to be 0.91min-1 and 0.86μM respectively.
Enzyme activity after resealing within ghost erythrocyte cells, and protection by α-crystallin against fructose-induced inactivation
Authors: DERHAM Barry K. , HARDING John J.
Published: February 2003

The role of α-crystallin as a molecular chaperone has been shown in many in vitro studies. In the present paper, we report on the chaperone function of α-crystallin within resealed erythrocyte ghosts. Eight enzymes were individually resealed within erythrocyte ghosts and assayed at zero time and at 24h. The ghost cell suspension was separated into soluble and membrane fractions. Five of the enzymes had significantly greater enzyme activity after 24h than the control within the soluble fractions. Fructation caused a decrease in enzyme activity (relative to the control). Resealing of α-crystallin within the ghost cell alongside the enzymes protected against inactivation by fructose within the soluble fraction.
Dictyostelium discoideum has a single diacylglycerol kinase gene with similarity to mammalian θ isoforms
Authors: ROCHE Marc A. de la , SMITH Janet L. , RICO Maribel , CARRASCO Silvia , MERIDA Isabel , LICATE Lucila , CÔTÉ Graham P. , EGELHOFF Thomas T.
Published: February 2003

Diacylglycerol kinases (DGKs) phosphorylate the neutral lipid diacylglycerol (DG) to produce phosphatidic acid (PA). In mammalian systems DGKs are a complex family of at least nine isoforms that are thought to participate in down-regulation of DG-based signalling pathways and perhaps activation of PA-stimulated signalling events. We report here that the simple protozoan amoeba Dictyostelium discoideum appears to contain a single gene encoding a DGK enzyme. This gene, dgkA, encodes a deduced protein that contains three C1-type cysteine-rich repeats, a DGK catalytic domain most closely related to the θ subtype of mammalian DGKs and a C-terminal segment containing a proline/glutamine-rich region and a large aspargine-repeat region. This gene corresponds to a previously reported myosin II heavy chain kinase designated myosin heavy chain-protein kinase C (MHC-PKC), but our analysis clearly demonstrates that this protein does not, as suggested by earlier data, contain a protein kinase catalytic domain. A FLAG-tagged version of DgkA expressed in Dictyostelium displayed robust DGK activity. Earlier studies indicating that disruption of this locus alters myosin II assembly levels in Dictyostelium raise the intriguing possibility that DG and/or PA metabolism may play a role in controlling myosin II assembly in this system.
Differential targeting of the stress mitogen-activated protein kinases to the c-Jun dimerization protein 2
Authors: KATZ Sigal , ARONHEIM Ami
Published: February 2003

The mitogen-activated kinases are structurally related proline-directed serine/threonine kinases that phosphorylate similar phosphoacceptor sites and yet, in vivo, they exhibit stringent substrate specificity. Specific targeting domains (kinase docking domains) facilitate kinase—substrate interaction and play a major role in substrate specificity determination. The c-Jun N-terminal kinase (JNK) consensus docking domain comprises of a KXXK/RXXXXLXL motif located in the Δ-domain of the c-Jun N-terminal to the phosphoacceptor site. The c-Jun dimerization protein 2 is phosphorylated by JNK on Thr-148. Activating transcription factor 3 (ATF3) is a basic leucine zipper protein which is highly homologous to c-Jun dimerization protein 2 (JDP2), especially within the threonine/proline phosphoacceptor site, Thr-148. Nevertheless, ATF3 does not serve as a JNK substrate in vitro or in vivo. Using ATF3 and JDP2 protein chimaeras, we mapped the JNK-docking domain within JDP2. Although a JNK consensus putative docking site is located within the JDP2 leucine zipper motif, this domain does not function to recruit JNK to JDP2. A novel putative docking domain located C-terminally to the JDP2 phosphoacceptor site was identified. This domain, when fused to the ATF3 heterologous phosphoacceptor site, can direct its phosphorylation by JNK. In addition, although the novel JNK-docking domain was found to be necessary for p38 phosphorylation of JDP2 on Thr-148, it was not sufficient to confer JDP2 phosphorylation by the p38 kinase.
Positive feedback of protein kinase C proteolytic activation during apoptosis
Authors: LEVERRIER Sabrina , VALLENTIN Alice , JOUBERT Dominique
Published: February 2003

In contrast with protein kinase Cα (PKCα) and PKC∊, which are better known for promoting cell survival, PKCΔ is known for its pro-apoptotic function, which is exerted mainly through a caspase-3-dependent proteolytic activation pathway. In the present study, we used the rat GH3B6 pituitary adenoma cell line to show that PKCα and PKC∊ are activated and relocalized together with PKCΔ when apoptosis is induced by a genotoxic stress. Proteolytic activation is a crucial step used by the three isoforms since: (1) the catalytic domains of the PKCα, PKC∊ or PKCΔ isoforms (CDα, CD∊ and CDΔ respectively) accumulated, and this accumulation was dependent on the activity of both calpain and caspase; and (2) transient expression of CDα, CD∊ or CDΔ sufficed to induce apoptosis. However, following this initial step of proteolytic activation, the pathways diverge; cytochrome c release and caspase-3 activation are induced by CD∊ and CDΔ, but not by CDα. Another interesting finding of the present study is the proteolysis of PKCΔ induced by CD∊ expression that revealed the existence of a cross-talk between PKC isoforms during apoptosis. Hence the PKC family may participate in the apoptotic process of pituitary adenoma cells at two levels: downstream of caspase and calpain, and via retro-activation of caspase-3, resulting in the amplification of its own proteolytic activation.
Acyl-CoA binding protein is an essential protein in mammalian cell lines
Authors: FÆRGEMAN Nils J. , KNUDSEN Jens
Published: February 2003

In the present work, small interference RNA was used to knock-down acyl-CoA binding protein (ACBP) in HeLa, HepG2 and Chang cells. Transfection with ACBP-specific siRNA stopped growth, detached cells from the growth surface and blocked thymidine and acetate incorporation. The results show that depletion of ACBP in mammalian cells results in lethality, suggesting that ACBP is an essential protein.
Critical Perspectives on Information Systems: An Impression of the Research Landscape
Authors: Brooke Carole
Published: February 2003

This article complements a paper in an earlier special issue of this volume of the Journal of Information Technology which was entitled ‘What Does it Mean to be “Critical” in IS Research?’ That paper conducted a preliminary review of the state of critical thinking in the fields of information systems (IS) and organization. In addressing the question ‘what is critical research?’ it showed how its definition has changed and broadened over time. This paper follows on by opening up some key questions relating to why researchers in IS should view critical research as having a valuable contribution to make. It begins by considering the apparently wide range of researchers for whom critical research has become an activity. Noting earlier calls for more empirical research, the paper looks at some examples of specific empirical applications. This leads us to consider how critical research impacts upon actual IS praxis, in particular the role of the IS professional, systems development and changes in the nature of organizational life itself. This is not intended to be a comprehensive review of the literature. Rather by drawing upon a sample of material covering a range of perspectives it aims to give an impression of the many developments in critical studies on organization and IS and to consider their implications for future direction.
Comprehension of Algebraic Expressions by Experienced users of Mathematics
Authors: Jansen Anthony R. , Marriott Kim , Yelland Greg W.
Published: February 2003

Little is known about how people comprehend mathematical expressions. In the present study we investigate the internal representations used by experienced users of mathematics to encode algebraic expressions. Initially, a memory recognition task was conducted that examined the role of mathematical syntax in the encoding of algebraic expressions. The results indicate that participants could more readily identify those parts of a previously seen expression that were syntactically well formed than those that were not well formed, suggesting that syntax plays an important role. To determine the level of syntactic structure involved, a second recognition task was conducted. The results indicate that algebraic expressions are encoded into components that represent the phrasal constituents of the expression. However, the results of these experiments did not rule out the possibility that the visual processes of perceptual organization were used to encode the expressions, or that the data were a consequence of a mathematical “lexicon” of common mathematical “phrases” Three further experiments were conducted to examine this, the results of which indicate that the encoding of algebraic expressions is based primarily on processes that occur beyond the level of visual or “lexical” processing. This is consistent with our finding that syntactic structure plays a key role.
Further Evidence for Systematic Reliability Differences between Explicit and Implicit Memory Tests
Authors: Buchner Axel , Brandt Martin
Published: February 2003

Meier and Perrig (2000) as well as Buchner and Wippich (2000) have shown that simple dissociations between explicit and implicit memory measures need not reflect functional dissociations of hypothetical underlying memory systems. Instead, such dissociations may also result from the fact that some widely used implicit memory measures are simply less reliable than the explicit measures with which they have been compared. We extend this argument in two ways. First, we show that illusion-based memory measures such as the priming measures derived from fame and preference judgement tasks are also subject to the reliability problem. Second, we show that yes—no and two-alternative forced-choice paradigms should, and in fact do, yield virtually identical results as far as the reliability of the memory tests is concerned.
Stopping and Restarting an Unfolding Action at Various Times
Authors: McGarry Tim , Chua Romeo , Franks Ian M.
Published: February 2003

The ability to inhibit an unfolding action is usually investigated using a stop signal (or go—stop) task. The data from the stop-signal task are often described using a horse-race model whose key assumption is that each process (i.e., go, stop) exhibits stochastic independence. Using three variations of a coincident-timing task (i.e., go, go—stop, and go—stop—go) we extend previous considerations of stochastic independence by analysing the go latencies for prior effects of stopping. On random trials in the go—stop—go task the signal sweep was paused for various times at various distances before the target. Significant increases in latency errors were reported on those trials on which the signal was paused (p <.005). Further analyses of the pause trials revealed significant effects for both the stopping interval (p <.001) and the pause interval (p <.05). Tukey post hoc analyses demonstrated increased latency errors as a linear function of the stopping interval, as expected, and decreased latency errors as a nonlinear function of the pause interval. These latter results indicate that the latencies of the go process, as reflected in the latency errors, may not exhibit stochastic independence under certain conditions. Various control mechanisms were considered in an attempt to explain these data.
Gains and Losses in Action Memory
Authors: Engelkamp Johannes , Seiler Kerstin H.
Published: February 2003

Enacting action phrases (SPT for subject-performed task) produces better free recall than only learning the phrases verbally (VT for verbal task). A widespread explanation of the enactment effect is based on the distinction between item-specific and relational information. There is widespread agreement that the main reason is the excellent item-specific encoding by enactment. However, there is little direct evidence in the case of free recall. The role of relational information is less clear. We suggest that content-based relational encoding is better in VTs than in SPTs. In three experiments, in which multiple free recall testing used item gains and losses as indices of item-specific and content-based relational encoding, respectively, these assumptions were confirmed. Consistently more gains (indexing better item-specific encoding) and more losses (indexing poorer relational encoding) were observed in SPTs than in VTs (Experiments 1 and 2). Furthermore, it was demonstrated that the content-based relational information underlying losses is not identical with order-relational information (Experiment 2). In Experiment 3, it was shown that an item-specific orienting task for VTs produced an equivalent number of item gains and losses as did the SPT condition.
Inspection Times and the Selection Task: What do Eye-Movements Reveal about Relevance Effects?
Authors: Ball Linden J. , Lucas Erica J. , Miles Jeremy N. V. , Gale Alastair G.
Published: February 2003

Three experiments are reported that used eye-movement tracking to investigate the inspection-time effect predicted by Evans’ (1996) heuristic-analytic account of the Wason selection task. Evans’ account proposes that card selections are based on the operation of relevance-determining heuristics, whilst analytic processing only rationalizes selections. As such, longer inspection times should be associated with selected cards (which are subjected to rationalization) than with rejected cards. Evidence for this effect has been provided by Evans (1996) using computer- presented selection tasks and instructions for participants to indicate (with a mouse pointer) cards under consideration. Roberts (1998b) has argued that mouse pointing gives rise to artefactual support for Evans’ predictions because of biases associated with the task format and the use of mouse pointing. We eradicated all sources of artefact by combining careful task constructions with eye-movement tracking to measure directly on-line attentional processing. All three experiments produced good evidence for the robustness of the inspection-time effect, supporting the predictions of the heuristic-analytic account.
Learned Changes in the Sensitivity of Stimulus Representations: Associative and Nonassociative Mechanisms
Authors: Hall Geoffrey
Published: February 2003

Central to associative learning theory is the proposal that the concurrent activation of a pair of event representations will establish or strengthen a link between them. Associative theorists have devoted much energy to establishing what representations are involved in any given learning paradigm and the rules that determine the degree to which the link is strengthened. They have paid less attention to the question of what determines that a representation will be activated, assuming, for the case of classical conditioning, that presentation of an appropriately intense stimulus from an appropriate modality will be enough. But this assumption is unjustified. Ipresent the results of experiments on the effects of stimulus exposure in rats that suggest that mere exposure to a stimulus can influence its perceptual effectiveness—that the ability of a stimulus to activate its representation can be changed by experience. This conclusion is of interest for two reasons. First, it supplies a direct explanation for the phenomenon of perceptual learning—the enhancement of stimulus discriminability produced by some forms of stimulus exposure. Second, it poses a theoretical challenge in that it seems to require the existence of a learning mechanism outside the scope of those envisaged by current formal theories of associative learning. I offer some speculations as to how this mechanism might be incorporated into such theories.
Learned Irrelevance and Retrospective Correlation Learning
Authors: Baker A. G. , Murphy Robin A. , Mehta Rick
Published: February 2003

In 1973 Mackintosh reported an interference effect that he called learned irrelevance in which exposure to uncorrelated (CS/US) presentation of the unconditional stimulus (US) and the conditioned stimulus (CS) interfered with future Pavlovian conditioning. It has been argued that there is no specific interference effect in learned irrelevance; rather the interference is the sum of independent CS and US exposure effects (CS + US). We review previous research on this question and report two new experiments. We conclude that learned irrelevance is a consequence of a contingency learning and a specific learned irrelevance mechanism. Moreover even the “independent exposure controls”, used in previous experiments to support the CS and US exposure account, provide support for the correlation learning process.
The Interaction between Discriminative Stimuli and Outcomes during Instrumental Learning
Authors: Dickinson Anthony , de Wit Sanne
Published: February 2003

Rats were trained on a biconditional discrimination in which the delivery of a food pellet stimulus signalled that pressing on one of two levers would be reinforced, whereas the delivery of a sucrose solution stimulus signalled that the reward was contingent on pressing the other lever. The outcome was the same food type as the discriminative stimulus in the congruent group but the other food type in the incongruent group. Both responses were rewarded with the same outcome in the same group. All the three groups learned the discrimination at statistically indistinguishable rates. Prefeeding one of the outcomes selectively reduced the associated response thereby demonstrating that responding was mediated by a representation of the outcome. Moreover, the outcome of one trial controlled responding on the next trial in accord with the stimulus function of the food type. These results are discussed in relation to the associative structures mediating the discriminative control of instrumental performance.
A Quantifier Approach to Negation in Natural Languages
Authors: Weiß Helmut
Published: February 2003

This article attempts to give a uniform and coherent analysis of the semantics and syntax of negation, with special emphasis on negative concord (NC) constructions. It is argued that negation is semantically a tripartite quantifier binding the event variable in its restriction. In syntax, this logical form corresponds to a structure where a NegP is present with Neg ° (normally) hosting the negative particle and a specifier as a checking position in the Minimalist sense. As a consequence, negative indefinites are held to be weak indefinites with a formal feature NEG which has to be checked away (thus obtaining Neg absorption). Additionally, some new data are introduced showing that even English style negative indefinites are analysable as non-negated weak indefinites.
Negation in C: The Syntax of Negated Verbs in Old Norse
Authors: Eythórsson Thórhallur
Published: February 2003

The syntax of finite verbs with the negation suffix -a/-atin early Old Norse reveals an asymmetry regarding the position of the verb relative to the subject in main clauses. The subject is regularly preceded by the negated verb, but followed by the verb in affirmative clauses. The asymmetry suggests that the subject is canonically in SpecIP. In affirmative subject-initial main clauses the finite verb moves to I, but the negated verbs obligatorily move to C. The movement of negated verbs to C is triggered by a [+neg] feature in this position. This assumption is independently motivated by the existence of the overt and non-overt negative complementizers in a variety of languages. The analysis advanced here supports the hypothesis that cross-linguistically sentential negation can be structurally represented in C.
Cell adhesion molecules involved in the leukocyte recruitment induced by venom of the snake Bothrops jararaca
Authors: Zamuner Stella R. , Teixeira Catarina F. P.
Published: February 2003

It has been shown that Bothrops jararaca venom (BjV) induces a significant leukocyte accumulation, mainly neutrophils, at the local of tissue damage. Therefore, the role of the adhesion molecules intercellular adhesion molecule‐1 (ICAM‐1), LECAM‐1, CD18, leukocyte function‐associated antigen‐1 (LFA‐1) and platelet endothelial cell adhesion molecule‐1 (PECAM‐1) on the BjV‐induced neutrophil accumulation and the correlation with release of LTB4, TXA2, tumor necrosis factor‐α, interleukin (IL)‐1 and IL‐6 have been investigated. Anti‐mouse LECAM‐1, LFA‐1, ICAM‐1 and PECAM‐1 monoclonal antibody injection resulted in a reduction of 42%, 80%, 66% and 67%, respectively, of neutrophil accumulation induced by BjV (250 μg/kg, intraperitoneal) injection in male mice compared with isotype‐matched control injected animals. The anti‐mouse CD18 monoclonal antibody had no significant effect on venom‐induced neutrophil accumulation. Concentrations of LTB4, TXA2, IL‐6 and TNF‐α were significant increased in the peritoneal exudates of animals injected with venom, whereas no increment in IL‐1 was detected. This results suggest that ICAM‐1, LECAM‐1, LFA‐1 and PECAM‐1, but not CD18, adhesion molecules are involved in the recruitment of neutrophils into the inflammatory site induced by BjV. This is the first in vivo evidence that snake venom is able to up‐regulate the expression of adhesion molecules by both leukocytes and endothelial cells. This venom effect may be indirect, probably through the release of the inflammatory mediators evidenced in the present study.
Some Properties of R. G. D. Allen's Treatment of Kalecki's 1935 Model of Business Cycles
Authors: Baxley John V. , Moorhouse John C.
Published: February 2003

More than sixty-five years have passed since Michal Kalecki (1935) published one of the first formal mathematical models of business cycles. His paper presents a closed-form analytic solution. This characteristic, among others, sets Kalecki's work apart from that of contemporary literary business cycle theorists such as Friedrich A. Hayek (1935) and John Maynard Keynes (1936).
Transforming Growth Factor-β1 (TGF-β)–induced Apoptosis of Prostate Cancer Cells Involves Smad7-dependent Activation of p38 by TGF-β-activated Kinase 1 and Mitogen-activated Protein Kinase Kinase 3
Authors: Edlund Sofia , Bu Shizhong , Schuster Norbert , Aspenström Pontus , Heuchel Rainer , Heldin Nils-Erik , ten Dijke Peter , Heldin Carl-Henrik , Landström Maréne
Published: February 2003

The inhibitory Smad7, a direct target gene for transforming growth factor-β (TGF-β), mediates TGF-β1–induced apoptosis in several cell types. Herein, we report that apoptosis of human prostate cancer PC-3U cells induced by TGF-β1 or Smad7 overexpression is caused by a specific activation of the p38 mitogen-activated protein kinase pathway in a TGF-β–activated kinase 1 (TAK1)- and mitogen-activated protein kinase kinase 3 (MKK3)-dependent manner. Expression of dominant negative p38, dominant negative MKK3, or incubation with the p38 selective inhibitor [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole], prevented TGF-β1–induced apoptosis. The expression of Smad7 was required for TGF-β–induced activation of MKK3 and p38 kinases, and endogenous Smad7 was found to interact with phosphorylated p38 in a ligand-dependent manner. Ectopic expression of wild-type TAK1 promoted TGF-β1–induced phosphorylation of p38 and apoptosis, whereas dominant negative TAK1 reduced TGF-β1–induced phosphorylation of p38 and apoptosis. Endogenous Smad7 was found to interact with TAK1, and TAK1, MKK3, and p38 were coimmunoprecipitated with Smad7 in transiently transfected COS1 cells. Moreover, ectopically expressed Smad7 enhanced the coimmunoprecipitation of HA-MKK3 and Flag-p38, supporting the notion that Smad7 may act as a scaffolding protein and facilitate TAK1- and MKK3-mediated activation of p38.
Convergence of Non-clathrin- and Clathrin-derived Endosomes Involves Arf6 Inactivation and Changes in Phosphoinositides
Authors: Naslavsky Naava , Weigert Roberto , Donaldson Julie G.
Published: February 2003

The trafficking of two plasma membrane (PM) proteins that lack clathrin internalization sequences, major histocompatibility complex class I (MHCI), and interleukin 2 receptor α subunit (Tac) was compared with that of PM proteins internalized via clathrin. MHCI and Tac were internalized into endosomes that were distinct from those containing clathrin cargo. At later times, a fraction of these internalized membranes were observed in Arf6-associated, tubular recycling endosomes whereas another fraction acquired early endosomal autoantigen 1 (EEA1) before fusion with the “classical” early endosomes containing the clathrin-dependent cargo, LDL. After convergence, cargo molecules from both pathways eventually arrived, in a Rab7-dependent manner, at late endosomes and were degraded. Expression of a constitutively active mutant of Arf6, Q67L, caused MHCI and Tac to accumulate in enlarged PIP2-enriched vacuoles, devoid of EEA1 and inhibited their fusion with clathrin cargo-containing endosomes and hence blocked degradation. By contrast, trafficking and degradation of clathrin-cargo was not affected. A similar block in transport of MHCI and Tac was reversibly induced by a PI3-kinase inhibitor, implying that inactivation of Arf6 and acquisition of PI3P are required for convergence of endosomes arising from these two pathways.
Visualizing Lipid Raft Dynamics and Early Signaling Events during Antigen Receptor-mediated B-Lymphocyte Activation
Authors: Gupta Neetu , DeFranco Anthony L.
Published: February 2003

Recent biochemical evidence indicates that an early event in signal transduction by the B-cell antigen receptor (BCR) is its translocation to specialized membrane subdomains known as lipid rafts. We have taken a microscopic approach to image lipid rafts and early events associated with BCR signal transduction. Lipid rafts were visualized on primary splenic B lymphocytes from wild-type or anti-hen egg lysozyme BCR transgenic mice, and on a mature mouse B-cell line Bal 17 by using fluorescent conjugates of cholera toxin B subunit or a Lyn-based chimeric protein, which targets green fluorescent protein to the lipid raft compartment. Time-lapse imaging of B cells stimulated via the BCR with the antigen hen egg lysozyme, or surrogate for antigen anti-IgM, demonstrated that lipid rafts are highly dynamic entities, which move laterally on the surface of these cells and coalesce into large regions. These regions of aggregated lipid rafts colocalized with the BCR and tyrosine-phosphorylated proteins. Microscopic imaging of live B cells also revealed an inducible colocalization of lipid rafts with the tyrosine kinase Syk and the receptor tyrosine phosphatase CD45. These two proteins play indispensable roles in BCR-mediated signaling but are not detectable in biochemically purified lipid raft fractions. Strikingly, BCR stimulation also induced the formation of long, thread-like filopodial projections, similar to previously described structures called cytonemes. These B-cell cytonemes are rich in lipid rafts and actin filaments, suggesting that they might play a role in long-range communication and/or transportation of signaling molecules during an immune response. These results provide a window into the morphological and molecular organization of the B-cell membrane during the early phase of BCR signaling.
Identification of a Novel Leucine-rich Repeat Protein as a Component of Flagellar Radial Spoke in the AscidianCiona intestinalis
Authors: Padma Potturi , Satouh Yuhkoh , Wakabayashi Ken-ichi , Hozumi Akiko , Ushimaru Yuji , Kamiya Ritsu , Inaba Kazuo
Published: February 2003

Axonemes are highly organized microtubule-based structures conserved in many eukaryotes. In an attempt to study axonemes by a proteomics approach, we selectively cloned cDNAs of axonemal proteins by immunoscreening the testis cDNA library from the ascidianCiona intestinalis by using an antiserum against whole axonemes. We report here a 37-kDa protein of which cDNA occurred most frequently among total positive clones. This protein, named LRR37, belongs to the class of SDS22+ leucine-rich repeat (LRR) family. LRR37 is different from the LRR outer arm dynein light chain reported inChlamydomonas and sea urchin flagella, and thus represents a novel axonemal LRR protein. Immunoelectron microscopy by using a polyclonal antibody against LRR37 showed that it is localized on the tip of the radial spoke, most likely on the spoke head. The LRR37 protein in fact seems to form a complex together with radial spoke protein 3 in a KI extract of the axonemes. These results suggest that LRR37 is a component of the radial spoke head and is involved in the interaction with other radial spoke components or proteins in the central pair projection.
IKKα Regulates Mitogenic Signaling through Transcriptional Induction of Cyclin D1 via Tcf
Authors: Albanese Chris , Wu Kongming , D'Amico Mark , Jarrett Christy , Joyce David , Hughes Julian , Hulit James , Sakamaki Toshiyuki , Fu Maofu , Ben-Ze'ev Avri , Bromberg Jacqueline F. , Lamberti Carmela , Verma Udit , Gaynor Richard B. , Byers Stephen W. , Pestell Richard G.
Published: February 2003

The Wnt/β-catenin/Tcf and IκB/NF-κB cascades are independent pathways involved in cell cycle control, cellular differentiation, and inflammation. Constitutive Wnt/β-catenin signaling occurs in certain cancers from mutation of components of the pathway and from activating growth factor receptors, including RON and MET. The resulting accumulation of cytoplasmic and nuclear β-catenin interacts with the Tcf/LEF transcription factors to induce target genes. The IκB kinase complex (IKK) that phosphorylates IκB contains IKKα, IKKβ, and IKKγ. Here we show that the cyclin D1 gene functions as a point of convergence between the Wnt/β-catenin and IκB pathways in mitogenic signaling. Mitogenic induction of G1-S phase progression and cyclin D1 expression was PI3K dependent, and cyclin D1−/−cells showed reduced PI3K-dependent S-phase entry. PI3K-dependent induction of cyclin D1 was blocked by inhibitors of PI3K/Akt/IκB/IKKα or β-catenin signaling. A single Tcf site in the cyclin D1 promoter was required for induction by PI3K or IKKα. In IKKα−/−cells, mitogen-induced DNA synthesis, and expression of Tcf-responsive genes was reduced. Reintroduction of IKKα restored normal mitogen induction of cyclin D1 through a Tcf site. In IKKα−/−cells, β-catenin phosphorylation was decreased and purified IKKα was sufficient for phosphorylation of β-catenin through its N-terminus in vitro. Because IKKα but not IKKβ induced cyclin D1 expression through Tcf activity, these studies indicate that the relative levels of IKKα and IKKβ may alter their substrate and signaling specificities to regulate mitogen-induced DNA synthesis through distinct mechanisms.