Systemic absorptive capacity: creating early-to-market returns through R&D alliances

For most complex emergent technologies, product-market success depends on efficient linkages between changing lead innovators within the R&D process. In this paper, our unit of analysis is a complex high technology product and the system of alliance linkages formed to progress a product through R&D milestones. We present a model and evidence for advancing our understanding of how achieving early-to-market returns depends on systemic absorptive capacity. This systemic absorptive capacity is the cumulative efficiency in the use of absorptive capacity to link changing lead innovators across successive milestones in R&D product development. We advance propositions of how systemic absorptive capacity can explain performance differences between rival product development systems competing for early-to-market returns with similar products through accelerating speed to market, cost and quality advantages. These explanations are contrasted with the conclusions of previous studies that have focused on absorptive capacity of single firms or single alliances in RD.

A simple and unified approach to human voluntary movements

In his provocative article, F. Mechsner (2004) advances the thesis that human voluntary movements are subject to psychological or perceptual -cognitive control and are thus organized without regard to efferent patterns (p. 355). Rather than considering in detail the experiments that he proffered by way of support, the present author discusses the degree to which that supposition has appeal on the grounds of simplicity and is defined in terms that are compatible with a unified science.

Preserved obstacle avoidance during reaching in patients with left visual neglect

We asked 12 patients with left visual neglect to bisect the gap between two cylinders or to reach rapidly between them to a more distal target zone. Both tasks demanded a motor response but these responses were quite different in nature. The bisection response was a communicative act whereby the patient indicated the perceived midpoint. The reaching task carried no imperative to bisect the gap, only to maintain a safe distance from either cylinder while steering to the target zone. Optimal performance on either task could only be achieved by reference to the location of both cylinders. Our analysis focused upon the relative influence of the left and right cylinders on the lateral location of the response. In the bisection task, all neglect patients showed qualitatively the same asymmetry, with the left cylinder exerting less influence than the right. In the reaching task, the neglect group behaved like normal subjects, being influenced approximately equally by the two cylinders. This was true for all bar two of the patients, who showed clear neglect in both tasks. We conclude that the visuomotor processing underlying obstacle avoidance during reaching is preserved in most patients with left visual neglect. (C) 2004 Elsevier Ltd. All rights reserved.

"mind the gap": The size-distance dissociation in visual neglect is a cueing effect

There is a growing body of evidence that the processes mediating the allocation of spatial attention within objects may be separable from those governing attentional distribution between objects. In the neglect literature, a related proposal has been made regarding the perception of (within-object) sizes and (between-object) distances. This proposal follows observations that, in size-matching and bisection tasks, neglect is more strongly expressed when patients are required to attend to the sizes of discrete objects than to the (unfilled) distances between objects. These findings are consistent with a partial dissociation between size and distance processing, but a simpler alternative must also be considered. Whilst a neglect patient may fail to explore the full extent of a solid stimulus, the estimation of an unfilled distance requires that both endpoints be inspected before the task can be attempted at all. The attentional cueing implicit in distance estimation tasks might thus account for their superior performance by neglect patients. We report two bisection studies that address this issue. The first confirmed, amongst patients with left visual neglect, a reliable reduction of rightward error for unfilled gap stimuli as compared with solid lines. The second study assessed the cause of this reduction, deconfounding the effects of stimulus type (lines vs. gaps) and attentional cueing, by applying an explicit cueing manipulation to line and gap bisection tasks. Under these matched cueing conditions, all patients performed similarly on line and gap bisection tasks, suggesting that the reduction of neglect typically observed for gap stimuli may be attributable entirely to cueing effects. We found no evidence that a spatial extent, once fully attended, is judged any differently according to whether it is filled or unfilled.

Initiation of evasive manoeuvres during self-motion: a test of three hypotheses

To understand performance of evasive and interceptive actions it is important to know how people decide when to initiate a movement - initiating at the 'right' moment is often essential for successful performance. It has been proposed that initiation is triggered when a perceptually derived quantity reaches an invariant criterion value. Candidate quantities include time-to-collision (TTC), distance, and rate of image expansion ( ROE), all of which have received empirical support. We studied initiation of an evasive manoeuvre in a computer-simulated steering task in which the observer was required to steer through a stationary visual environment and avoid colliding with an obstacle in their path. The results could not be explained by hypotheses which propose that evasive manoeuvre initiation is based on a fixed criterion value of TTC or distance. The overall pattern was, however, consistent with the use of a criterion ROE value. This was further tested by analyses designed to directly evaluate whether the ROE value used to initiate the response was the same across experimental conditions. Only two of the six participants showed evidence for using the ROE strategy.

Effector dynamics of rhythmic wrist activity and its implications for (modeling) bimanual coordination

To examine the role of the effector dynamics of the wrist in the production of rhythmic motor activity, we estimated the phase shifts between the EMG and the task-related output for a rhythmic isometric torque production task and an oscillatory movement, and found a substantial difference (45-52degrees) between the two. For both tasks, the relation between EMG and task-related output (torque or displacement) was adequately reproduced with a physiologically motivated musculoskeletal model. The model simulations demonstrated the importance of the contribution of passive structures to the overall dynamics and provided an account for the observed phase shifts in the dynamic task. Additional simulations of the musculoskeletal model with added load suggested that particular changes in the phase relation between EMG and movement may follow largely from the intrinsic muscle dynamics, rather than being the result of adaptations in the neural control of joint stiffness. The implications of these results are discussed in relation to (models of) interlimb coordination in rhythmic tasks. (C) 2004 Elsevier B.V. All rights reserved.

Movement trajectories in the presence of a distracting stimulus: Evidence for a response activation model of selective reaching

Consistent with action-based theories of attention, the presence of a nontarget stimulus in the environment has been shown to alter the characteristics of goal-directed movements. Specifically, it has been reported that movement trajectories veer away from (Howard & Tipper, 1997) or towards (Welsh, Elliott, & Weeks, 1999) the location of a nontarget stimulus. The purpose of the experiments reported in this paper was to test a response activation model of selective reaching conceived to account for these variable results. In agreement with the model, the trajectory changes in the movements appear to be determined by the activation levels of each competing response at the moment of response initiation. The results of the present work, as well as those of previous studies, are discussed within the framework of the model of response activation.

Bait avoidance and habitat use by the roof rat, Rattus rattus, in a piggery

The acceptance of four anticoagulant rodenticide baits was evaluated in a piggery. The bait bases were cracked wheat, wax block, pig feed, and Racumin Paste(R). Mean daily consumption of each bait was poor (< 5 g). Mean activity index measured with tracking plates did not change significantly throughout pre-baiting (3 days), baiting (37) or post-baiting (7), indicating that the baits had no impact on the population. The same baiting regime applied simultaneously in nearby stables with lower feed availability induced a significantly higher mean consumption of the cracked wheat based bait, and the activity index declined to zero at day 23, indicating that the rats were eradicated. The failure of the baits to control rats in the piggery was possibly due to the poor bait acceptance caused by the abundant feed supply. Results of live-trapping and radio- and spool-and-line tracking indicated that the population was confined within the piggery; lower windowsills were the most used above-ground structure for movements; and minimum home range span was 17 m. We suggest that rodent control should be implemented within the confines of the piggery to reduce the risk to non-target animals, and that mortality agents should be placed less than or equal to 17 in apart arboreally for the roof rat. (C) 2004 Elsevier Ltd. All rights reserved.

Hurt feelings in couple relationships: Towards integrative models of the negative effects of hurtful events

Previous research suggests that hurt feelings can have powerful effects on individual and relational outcomes. This study examined a typology of hurtful events in couple relationships, together with integrative models predicting ongoing effects on victims and relationships. Participants were 224 students from introductory and third-year psychology classes, who completed open-ended and structured measures concerning an event in which a partner had hurt their feelings. By tailoring Leary et al.'s (1998) typology to the context of romantic relationships, five categories of hurtful events were proposed: active disassociation, passive disassociation, criticism, infidelity, and deception. Analyses assessing similarities and differences among the categories confirmed the utility of the typology. Structural equation modeling showed that longer-term effects on the victim were predicted by relationship anxiety and by the victim's immediate reactions to the event (negative emotions and self-perceptions; feelings of rejection and powerlessness). In contrast, ongoing effects on the relationship were predicted by avoidance, the victim's attributions and perceptions of offender remorse, and the victim's own behavior. The results highlight the utility of an integrated approach to hurt, incorporating emotional, cognitive, and behavioral responses, and dimensions of attachment security.

Pretend play, mirror self-recognition and imitation: A longitudinal investigation through the second year

The aim in the current study was to investigate the emergence of pretend play, mirror self-recognition, synchronic imitation and deferred imitation in normally developing human infants. A longitudinal study was conducted with 98 infants seen at three-monthly intervals from 12 through to 24 months of age. At each session the infants were tested on a range of tasks assessing the four target skills. Deferred imitation was found to emerge prior to synchronic imitation, pretend play and mirror self-recognition. In contrast, the latter three skills emerged between 18 and 21 months and followed similar developmental trajectories. Deferred imitation was found to hold a prerequisite relation with these three skills. Synchronic imitation, pretend play and mirror self-recognition were not closely associated and no prerequisite relations were found between these skills. These findings are discussed in the context of current theories regarding the development of pretend play, mirror self-recognition, synchronic imitation and deferred imitation in the second year. (C) 2004 Elsevier Inc. All rights reserved.

The composition of attachment networks throughout the adult years

This study assessed the structure of adults' attachment networks, using a questionnaire measure of preferred attachment figures with a large sample of adults (N = 812) representing various ages and life situations. Two broad research questions were addressed. The first question concerned the variety of attachment figures reported by adults and the relative strength of attachment to each, including preferred (primary) attachment figures. The second question concerned the effects of normative life events on attachment networks and the nature of primary attachment figures in different life situations. Overall, the results supported the preeminent role of attachment relationships with romantic partners. However, relationships with mothers, fathers, siblings, children, and friends also met the strict criteria used to define full-blown attachments; further, each of these targets constituted the primary attachment figure for some participants. The structure of the attachment network was related to variables such as age, relationship status, and parental status, attesting to the important role of normative life events. The results have theoretical and applied significance and are related to principles of attachment, caregiving, and socioemotional selectivity.

Binomial leap methods for simulating stochastic chemical kinetics

This paper discusses efficient simulation methods for stochastic chemical kinetics. Based on the tau-leap and midpoint tau-leap methods of Gillespie [D. T. Gillespie, J. Chem. Phys. 115, 1716 (2001)], binomial random variables are used in these leap methods rather than Poisson random variables. The motivation for this approach is to improve the efficiency of the Poisson leap methods by using larger stepsizes. Unlike Poisson random variables whose range of sample values is from zero to infinity, binomial random variables have a finite range of sample values. This probabilistic property has been used to restrict possible reaction numbers and to avoid negative molecular numbers in stochastic simulations when larger stepsize is used. In this approach a binomial random variable is defined for a single reaction channel in order to keep the reaction number of this channel below the numbers of molecules that undergo this reaction channel. A sampling technique is also designed for the total reaction number of a reactant species that undergoes two or more reaction channels. Samples for the total reaction number are not greater than the molecular number of this species. In addition, probability properties of the binomial random variables provide stepsize conditions for restricting reaction numbers in a chosen time interval. These stepsize conditions are important properties of robust leap control strategies. Numerical results indicate that the proposed binomial leap methods can be applied to a wide range of chemical reaction systems with very good accuracy and significant improvement on efficiency over existing approaches. (C) 2004 American Institute of Physics.

Country of birth, country of residence, and menopausal transitions and symptoms: British birth cohort and Australian Longitudinal Study on Women's Health

Objective: To explore endocrine-related and general symptoms among three groups of middle-aged women defined by country of birth and country of residence, in the context of debates about biological, cultural and other factors in menopause. Methods: British-born women participating in a British birth cohort study (n=1,362) and age-matched Australian-born (n=1,724) and British-born (n=233) Australian women selected from the Australian Longitudinal Study on Women's Health (ALSWH) responded to two waves of surveys at ages 48 and 50. Results: Australian-Australian and British-Australian women report reaching menopause later than British-British women, even after accounting for smoking status and parity. Hormone replacement therapy (HRT) use was lower and hysterectomy was more common among both Australian groups, probably reflecting differences in health services between Britain and Australia. The Australian-Australian and British-Australian groups were more likely to report endocrine-related symptoms than the British-British group, even after adjusting for menopausal status. British-British women were more likely to report some general symptoms. Conclusions: Symptom reporting is high among Australian and British midlife women and varies by country of residence, country of birth and menopausal status. Implications: The data do not support either a simple cultural or a simple biological explanation for differences in menopause experience.