bluuebunny/crossref_metadata_2025_split huggingface dataset:
Muscarine activates the sodium–calcium exchanger via M3 receptors in basal forebrain neurons
Authors: Xu Changqing , Wu Min , Morozova Elena , Alreja Meenakshi 
Published: October 2006

AbstractNeurons of the medial septum/diagonal band of Broca (MSDB) project to the hippocampus. Muscarinic cholinergic mechanisms within the MSDB are potent modulators of hippocampal functions; intraseptal scopolamine disrupts and intraseptal carbachol facilitates hippocampus‐dependent learning and memory tasks, and the associated hippocampal theta rhythm. In earlier work, we demonstrated that, within the MSDB, the septohippocampal GABAergic but not cholinergic neurons are the primary target of muscarinic manipulations and that muscarinic activation of septohippocampal GABAergic neurons is mediated directly via M3 receptors. In the present study, we examined the ionic mechanism(s) underlying the excitatory actions of muscarine in these neurons. Using whole‐cell patch‐clamp recording techniques in rat brain slices, we demonstrated that M3 receptor‐mediated muscarinic activation of MSDB neurons is dependent on external Na+ and is also reduced by bath‐applied Ni2+ and KB‐R7943 as well as by replacing external Na+ with Li+, suggesting a primary involvement of the Na+–Ca2+ exchanger. We conclude that the M3 receptor‐mediated muscarinic activation of MSDB septohippocampal GABA‐type neurons, that is important for cognitive functioning, is mediated via activation of the Na+–Ca2+ exchanger.
A comparison of methods for mapping species ranges and species richness
Authors: Graham Catherine H. , Hijmans Robert J. 
Published: October 2006

ABSTRACTAim  Maps of species richness are the basis for applied research and conservation planning as well as for theoretical research investigating patterns of richness and the processes shaping these patterns. The method used to create a richness map could influence the results of such studies, but differences between these methods have been insufficiently evaluated. We investigate how different methods of mapping species ranges can influence patterns of richness, at three spatial resolutions.Location  California, USA.Methods  We created richness maps by overlaying individual species range maps for terrestrial amphibians and reptiles. The methods we used to create ranges included: point‐to‐grid maps, obtained by overlaying point observations of species occurrences with a grid and determining presence or absence for each cell; expert‐drawn maps; and maps obtained through species distribution modelling. We also used a hybrid method that incorporated data from all three methods. We assessed the correlation and similarity of the spatial patterns of richness maps created with each of these four methods at three different resolutions.Results  Richness maps created with different methods were more correlated at lower spatial resolutions than at higher resolutions. At all resolutions, point‐to‐grid richness maps estimated the lowest species richness and those derived from species distribution models the highest. Expert‐drawn maps and hybrid maps showed intermediate levels of richness but had different spatial patterns of species richness from those derived with the other methods.Main conclusions  Even in relatively well‐studied areas such as California, different data sources can lead to rather dissimilar maps of species richness. Evaluating the strengths and weaknesses of different methods for creating a richness map can provide guidance for selecting the approach that is most appropriate for a given application and region.
Is the Rapoport effect widespread? Null models revisited
Authors: Ribas Carla R. , Schoereder José H. 
Published: October 2006

ABSTRACTAim To test the Rapoport effect using null models and data sets taken from the literature. We propose an improvement on an existing method, testing the Rapoport effect in elevational and latitudinal distributions when distributions are restricted by sampling.Location Global.Methods First, we hypothesized that real range size distributions are similar to those expected by null assumptions (expected by only imposing boundaries to species distributions). When these distributions were different from those expected under the null assumptions, we tested the hypothesis that these distributions correspond to those expected when a Rapoport effect occurs. We used two simulation methods, random and pseudo‐random, which differed only in that the latter one assumes fixed species mid‐points, coinciding with real mid‐points. Observed correlations between range size and mid‐point were compared with the frequency distribution of 1000 simulations, using both simulation methods. We compared the correlation curves generated by 1000 simulations with those of the observed distributions, testing whether correlations indicated a Rapoport effect.Results Several significant patterns of correlations between range size and mid‐point were observed in the data sets when compared with random and pseudo‐random simulations. However, few of these correlations were consistent with a Rapoport effect.Main conclusions Although some recent studies are consistent with a Rapoport effect, our results suggest that the Rapoport effect is not a widespread pattern in global ecology.
The foundations of psychological understanding
Authors: Goswami Usha 
Published: October 2006

Abstract In this paper, I review some recent submissions to Developmental Science that advance our understanding of psychological development. More and more submissions to the journal explore the origins of knowledge and, for psychological knowledge, such origins are multiple. Here I consider the contribution of mechanisms such as contingency detection, gaze following and gaze monitoring, social referencing and joint attention to emergent psychological understanding. I also consider infant understanding of goal‐directed action, and the intimate connection between language acquisition and psychological development. The centrality of intention‐reading skills to both language and social cognition is highlighted.
Physiological and behavioral parameters of infants’ categorization: changes in heart rate and duration of examining across trials
Authors: Elsner Birgit , Pauen Sabina , Jeschonek Susanna 
Published: October 2006

Abstract This report investigates the relations between duration of examining and heart rate (HR) across several trials of an object‐examination task. A total of N= 20 11‐month‐olds were familiarized with a sequence of 10 different exemplars from the same global category (animals or furniture) before they received an exemplar from the contrasting category at test. Consistent with previous findings, HR was lower during states of focused attention (i.e. examining) than during states of casual attention (i.e. looking) or non‐looking. Over the familiarization trials, examining stayed about the same, while mean HR increased. At test, examining increased and mean HR decreased, indicating that infants focused their attention on the out‐of‐category object. Psychophysiological and behavioral measures of attention were systematically related over trials, suggesting that heart rate provides a suitable objective measure to study infants’ categorization performance in object‐examination tasks.
Two‐year‐olds grasp the intentional structure of pretense acts
Authors: Rakoczy Hannes , Tomasello Michael 
Published: October 2006

Abstract Twenty‐two‐ and 27‐month‐old children were tested for their understanding of pretending as a specific intentional action form. Pairs of superficially similar behaviors – pretending to perform an action and trying to perform that action – were demonstrated to children. The 27‐month‐olds, and to some degree the 22‐month‐olds, showed in their responses that they understood the intentional structure of both kinds of behaviors: after pretense models, they themselves performed appropriate inferential pretense acts, whereas after the trying models they properly performed the action or tried to perform it with novel means. These findings are discussed in the light of recent debates about children's developing understanding of pretense and theory of mind.
Imitation of hierarchical action structure by young children
Authors: Whiten Andrew , Flynn Emma , Brown Katy , Lee Tanya 
Published: October 2006

AbstractTo provide the first systematic test of whether young children will spontaneously perceive and imitate hierarchical structure in complex actions, a task was devised in which a set of 16 elements can be modelled through either of two different, hierarchically organized strategies. Three‐year‐old children showed a strong and significant tendency to copy whichever of the two hierarchical approaches they witnessed an adult perform. Responses to an element absent in demonstrations, but present at test, showed that children did not merely copy the chain of events they had witnessed, but acquired hierarchically structured rules to which the new element was assimilated. Consistent with this finding, children did not copy specific sequences of actions at lower hierarchical levels.
Context sensitivity in children's reasoning about ability across the elementary school years
Authors: Heyman Gail D. , Compton Brian J. 
Published: October 2006

AbstractChildren's sensitivity to context when making inferences about ability was investigated. In three studies, elementary school children (ages 5 to 10, total N = 332) were asked to reason about the relation between academic ability and the speed with which characters completed puzzle tasks. Participants were primed to interpret the characters’ task completion rates with reference to either (1) the character's perceptions of the difficulty of the task, or (2) the character's level of effort on the task. Children who were primed to consider the perceived difficulty of the task were more likely to view ability as a static quality, a pattern of reasoning that included a tendency to associate task completion rates with ability, and to agree that not all individuals are capable of achieving high levels of success. These results provide evidence that even early elementary school children are sensitive to subtle contextual cues when making inferences about ability, and are consistent with the possibility that children make use of implicit cues available to them in their social environment to derive meaning from achievement situations.
Brain–behavior relationships in reading acquisition are modulated by socioeconomic factors
Authors: Noble Kimberly G. , Wolmetz Michael E. , Ochs Lisa G. , Farah Martha J. , McCandliss Bruce D. 
Published: October 2006

AbstractFunctional neuroimaging may provide insights into the achievement gap in reading skill commonly observed across socioeconomic status (SES). Brain activation during reading tasks is known to be associated with individual differences in children's phonological language skills. By selecting children of equivalent phonological skill, yet diverse socioeconomic backgrounds, we use functional magnetic resonance imaging (fMRI) to demonstrate that a child's experience, as operationalized by SES, can systematically modulate the relationship between phonological language skills and reading‐related brain activity in left fusiform and perisylvian regions. Specifically, at lower socioeconomic levels, individual differences in skill result in large differences in brain activation. In contrast, as SES increases, this relationship between phonological language skill and activation is attenuated. Socioeconomic background factors are thus found to modulate brain–behavior relationships in reading, indicating that cognitive, social, and neurobiological influences on reading development are fundamentally intertwined.
Multiple Directorships and Corporate Performance in Australian Listed Companies*
Authors: Kiel Geoffrey C. , Nicholson Gavin J. 
Published: October 2006

How many directorships are too many? Globally, normative advice emphasises the importance of limiting the number of directorships any individual should hold due to the workloads they entail. However, there is little empirical evidence to support this view. Rather, there is a strong tradition of supporting multiple directorships as a mechanism for the firm to co‐opt external resources. To explore the issue of director workloads and multiple directorships, we first consider the issues related to multiple directorships and outline the conclusions of extant international and Australian studies into multiple directorships. We then detail our objectives in undertaking this research and our approach to data collection.Our findings indicate that the incidence of multiple directorships in Australian listed companies is low. We also find that many of the apparent examples of multiple directorships are due to related entities, which share common directors and, due to the nature of these entities, have much lower workload requirements. Further, there does not appear to be any relationship between holding multiple directorships and firm financial performance. Finally, we discuss the implications for boards and those interested in governance, particularly the need to ensure governance recommendations and guidelines reflect empirical findings. We offer one solution to address the concerns of boards, investors, other stakeholders and the community regarding multiple directorships: board and individual director evaluations.
Corporate Governance Options for the Local Subsidiaries of Multinational Enterprises*
Authors: Kiel Geoffrey C. , Hendry Kevin , Nicholson Gavin J. 
Published: October 2006

While the corporate governance literature generally focuses on the parent legal entity, many organisations are now multinational enterprises (MNEs) with subsidiaries that are most often legal entities in their host countries. Despite the strengthening of corporate governance regimes internationally, the boards of these subsidiaries are in many instances perfunctory. This paper examines the question of whether developments in corporate governance theory and practice can add value for the local subsidiaries of MNEs.This paper provides a theoretical basis for evaluating governance models in MNEs. The paper commences with a review of the key concepts from the MNE and conglomerates literature with respect to core MNE strategies. The paper then discusses what the “governance roles” are that must be performed in MNE subsidiaries. We propose four governance frameworks for subsidiary corporations. These frameworks are: (1) Direct Control; (2) Dual Reporting; (3) Advisory Board; (4) Local Board. We consider the strengths and weaknesses of each model in relation to international strategy theory. We conclude with recommendations for the conditions under which the various models may be appropriate and practical guidelines for the utilisation of corporate governance theory to improve MNE performance.
Semiparametric Estimation by Model Selection for Locally Stationary Processes
Authors: Van Bellegem Sébastien , Dahlhaus Rainer 
Published: October 2006

SummaryOver recent decades increasingly more attention has been paid to the problem of how to fit a parametric model of time series with time-varying parameters. A typical example is given by autoregressive models with time-varying parameters. We propose a procedure to fit such time-varying models to general non-stationary processes. The estimator is a maximum Whittle likelihood estimator on sieves. The results do not assume that the observed process belongs to a specific class of time-varying parametric models. We discuss in more detail the fitting of time-varying AR(p) processes for which we treat the problem of the selection of the order p, and we propose an iterative algorithm for the computation of the estimator. A comparison with model selection by Akaike's information criterion is provided through simulations.
The Complex Bingham Quartic Distribution and Shape Analysis
Authors: Kent J. T. , Mardia K. V. , McDonnell P. 
Published: October 2006

SummaryThe complex Bingham distribution was introduced by Kent as a tractable model for landmark-based shape analysis. It forms an exponential family with a sufficient statistic which is quadratic in the data. However, the distribution has too much symmetry to be widely useful. In particular, under high concentration it behaves asymptotically as a normal distribution, but where the covariance matrix is constrained to have complex symmetry. To overcome this limitation and to provide a full range of asymptotic normal behaviour, we introduce a new ‘complex Bingham quartic distribution’ by adding a selection of quartic terms to the log-density. In the simplest case this new distribution corresponds to Kent's FB5-distribution. Asymptotic and saddlepoint methods are developed for the normalizing constant to facilitate maximum likelihood estimation. Examples are given to show the usefulness of this new distribution.
Network Delay Tomography using Flexicast Experiments
Authors: Lawrence Earl , Michailidis George , Nair Vijayan N. 
Published: October 2006

SummaryEstimating and monitoring the quality of service of computer and communications networks is a problem of considerable interest. The paper focuses on estimating link level delay distributions from end-to-end path level data collected by using active probing experiments. This is an interesting large scale statistical inverse (deconvolution) problem. We describe a flexible class of probing experiments (‘flexicast’) for data collection and develop conditions under which the link level delay distributions are identifiable. Maximum likelihood estimation using the EM algorithm is studied. It does not scale well for large trees, so a faster algorithm based on solving for local maximum likehood estimators and combining their information is proposed. The usefulness of the methods is illustrated on real voice over Internet protocol data that were collected from the University of North Carolina campus network.
A Functional Wavelet–Kernel Approach for Time Series Prediction
Authors: Antoniadis Anestis , Paparoditis Efstathios , Sapatinas Theofanis 
Published: October 2006

SummaryWe consider the prediction problem of a time series on a whole time interval in terms of its past. The approach that we adopt is based on functional kernel nonparametric regression estimation techniques where observations are discrete recordings of segments of an underlying stochastic process considered as curves. These curves are assumed to lie within the space of continuous functions, and the discretized time series data set consists of a relatively small, compared with the number of segments, number of measurements made at regular times. We estimate conditional expectations by using appropriate wavelet decompositions of the segmented sample paths. A notion of similarity, based on wavelet decompositions, is used to calibrate the prediction. Asymptotic properties when the number of segments grows to ∞ are investigated under mild conditions, and a nonparametric resampling procedure is used to generate, in a flexible way, valid asymptotic pointwise prediction intervals for the trajectories predicted. We illustrate the usefulness of the proposed functional wavelet–kernel methodology in finite sample situations by means of a simulated example and two real life data sets, and we compare the resulting predictions with those obtained by three other methods in the literature, in particular with a smoothing spline method, with an exponential smoothing procedure and with a seasonal autoregressive integrated moving average model.
Separating Between- and Within-Cluster Covariate Effects by Using Conditional and Partitioning Methods
Authors: Neuhaus John M. , McCulloch Charles E. 
Published: October 2006

SummaryWe consider the situation where the random effects in a generalized linear mixed model may be correlated with one of the predictors, which leads to inconsistent estimators. We show that conditional maximum likelihood can eliminate this bias. Conditional likelihood leads naturally to the partitioning of the covariate into between- and within-cluster components and models that include separate terms for these components also eliminate the source of the bias. Another viewpoint that we develop is the idea that many violations of the assumptions (including correlation between the random effects and a covariate) in a generalized linear mixed model may be cast as misspecified mixing distributions. We illustrate the results with two examples and simulations.
Bashing the Migrant Climbers: Interethnic Classification Struggles in German City Neighborhoods
Authors: SUTTERLÜTY FERDINAND , NECKEL SIGHARD 
Published: October 2006

AbstractThis article examines the symbolic order of the relationships between various social groups in disadvantaged neighborhoods and shows that ethnicity is the main reference point of derogatory designations or ‘negative classifications’. Using two districts in German cities as examples, the semantic patterns of mutual negative classifications among autochthonous individuals and their Turkish neighbors are reconstructed. Upwardly mobile individuals of Turkish origin are the most frequent targets of stigmatization. This fact is explained by the existence of a deep symbolic dimension of social inequality that conceives of ethnicity in terms of kinship relations. The socially inclusive or exclusive effects of negative interethnic classifications and the related classification struggles depend on three factors: the internal, i.e. gradual or categorical logic of the classification patterns; the form and process of conflict resolution; and the social contexts in which negative classifications are used. While the disintegrating effects of negative classifications are curbed by institutionalized norms in local politics and economic life, there only exist informal performative norms of interaction in the life‐world, and here these classifications can more easily lead to social exclusion and ethnic separation.
Living with psoriasis
Authors: Wolkenstein P 
Published: October 2006

AbstractBackground  Psoriasis has a strong impact on quality of life and the viewpoints of patients and physicians are necessary for satisfactory therapy.Aim  To inform dermatologists on what represents ‘living with psoriasis’.Methods  We conducted a research using Medline with the following keywords: psoriasis, quality of life. Forty‐one papers were selected from a total of 369 papers.Results  As with other major medical chronic disorders, psoriasis has a severe impact on the life of patients. Patients with palmoplantar, pustular and arthropathic psoriasis are more likely to have a poorer quality of life. Emotionally charged body regions, e.g. the scalp, face, neck, forearms, hands and genital region, have a specific and significant impact. Living with psoriasis is to live with its symptoms, especially pruritus, and to live in vulnerable social isolation.Conclusions  As psoriasis has a strong impact on quality of life because of extensive skin involvement, clinical management should take these two criteria into account when making therapeutic decisions. The strong impact of new treatments on patient‐related outcomes probably leads to the conclusion that they improve life with psoriasis. Nevertheless, it is important to highlight that even a successful treatment does not impact on the psychological distress of the patients, the patients’ beliefs about psoriasis or their coping with the disease.