bluuebunny/crossref_metadata_2025_split huggingface dataset:
Are district general hospital patients with unstable angina at a disadvantage?
Authors: Miller C , Lipscomb K , Curzen N 
Published: March 2003

Abstract

Objective
To determine whether patients with non-ST elevation acute coronary syndromes requiring coronary angiography and revascularisation have inferior access to these services if admitted to district general hospitals (DGHs) compared with similar patients admitted to a base hospital containing a tertiary cardiac centre.

Design
Prospective, consecutive monitoring of all patients with acute coronary syndromes accepted by the tertiary cardiac centre for angiography and revascularisation over a three month period (1 April to 30 June 2002).

Participants
All patients accepted for angiography from DGHs and from within the base hospital with a diagnosis of acute coronary syndromes.

Setting
Tertiary cardiac facility (Manchester Heart Centre at Manchester Royal Infirmary (MRI)).

Main outcome measure
Time waited from referral to angiography and revascularisation.

Results
A total of 184 patients with a diagnosis of non-ST elevation acute coronary syndromes underwent angiography with a view to revascularisation. Of these, 89 (48%) were admitted initially to MRI and 95 (52%) were admitted to a feeder DGH. DGH patients waited significantly longer from admission to angiography than MRI patients (median 13 days (25th-75th percentiles 7–19) v 5 days (3–8) respectively; p&lt;0.0005). DGH patients therefore also waited longer from admission to revascularisation (15 days (6–20) v 6 days (3–9) respectively). Once transferred into the Manchester Heart Centre, DGH patients underwent angiography within a median of 1 day (1–2). More DGH patients than those from MRI underwent both coronary artery bypass grafting (21 (22%) v 8 (9%) respectively; p=0.015) and percutaneous coronary intervention (44 (46%) v 32 (36%) respectively; p=NS).

Conclusion
Patients admitted to feeder DGHs with non-ST elevation acute coronary syndromes wait significantly longer for access to invasive coronary assessment and revascularisation than similar patients admitted in the hospital that incorporates the tertiary cardiac centre. This inequity of access is determined by postcode rather than clinical priority.
Illumination of x-rays: the usual lights exposed
Authors: Blackshaw G R J C , Gostling J A , Appleton B N , Pearce N , Thomas G V , Lewis W G 
Published: March 2003

Abstract

Aims
Faced with pressure of work and limited resource, doctors frequently use the nearest available light to examine x-ray films. The aim of this study was to examine the relative intensities of hospital light sources, and to compare these with the light intensity guidelines (1500 to 3000 candelas) of the British Institute of Radiology.

Methods
The relative intensities of seven hospital light sources were examined using a standard light meter at a constant 30 cm from the source. A control group of 10 individual consultant’s x-ray viewing boxes were compared with six other ward based light sources.

Results
Only two light sources approached the British Institute of Radiology light intensity x-ray viewing criteria: the x-ray viewing boxes of consultant radiologists with a median light intensity of 3503 candelas (χ2=13.3, df 1; p=0.0001), and daylight from north facing windows with a median of 1464 candelas when overcast (χ2=8.571, df 1; p=0.003) and 4669 candelas in sunshine (χ2= 6.364, df 1; p=0.0001).

Conclusion
Few hospital light sources met the British Institute of Radiology guidelines. The long held high regard of artists for northern light appears justified even in the environment of a British district general hospital.
Signal Strength Determines the Nature of the Relationship Between Perception and Working Memory
Authors: Sheth Bhavin R. , Shimojo Shinsuke 
Published: March 2003

Abstract
Neurophysiological and behavioral studies have shown that perception and memory share neural substrates and functional properties. But are perception and the active working memory of a stimulus one and the same? To address this question in the spatial domain, we compared the percept and the working memory of the position of a target stimulus embedded within a surround of moving dots. Motion in a particular direction after the target's offset biased the memory of target location in the same direction. However, motion simultaneous with a high-contrast, perceptually strong target biased the percept of target location in the opposite direction. Thus, perception and working memory can be modified by motion in qualitatively different ways. Manipulations to strengthen the memory trace had no effect on the direction of the memory bias, indicating that memory signal strength can never equal that of the percept of a strong stimulus. However, the percept of a weak stimulus was biased in the direction of motion. Thus, although perception and working memory are not inherently different, they can differ behaviorally depending on the strength of the perceptual signal. Understanding how a changing surround biases neural representations in general, and postsensory processes in particular, can help one understand past reports of spatial mislocalization.
Dissociating Hippocampal versus Basal Ganglia Contributions to Learning and Transfer
Authors: Myers Catherine E. , Shohamy Daphna , Gluck Mark A. , Grossman Steven , Kluger Alan , Ferris Steven , Golomb James , Schnirman Geoffrey , Schwartz Ronald 
Published: March 2003

AbstractBased on prior animal and computational models, we propose a double dissociation between the associative learning deficits observed in patients with medial temporal (hippocampal) damage versus patients with Parkinson's disease (basal ganglia dysfunction). Specifically, we expect that basal ganglia dysfunction may result in slowed learning, while individuals with hippocampal damage may learn at normal speed. However, when challenged with a transfer task where previously learned information is presented in novel recombinations, we expect that hippocampal damage will impair generalization but basal ganglia dysfunction will not. We tested this prediction in a group of healthy elderly with mild-to-moderate hippocampal atrophy, a group of patients with mild Parkinson's disease, and healthy controls, using an “acquired equivalence” associative learning task. As predicted, Parkinson's patients were slower on the initial learning but then transferred well, while the hippocampal atrophy group showed the opposite pattern: good initial learning with impaired transfer. To our knowledge, this is the first time that a single task has been used to demonstrate a double dissociation between the associative learning impairments caused by hippocampal versus basal ganglia damage/dysfunction. This finding has implications for understanding the distinct contributions of the medial temporal lobe and basal ganglia to learning and memory.
A Computational Study into the Evolution of Dual-Route Dynamics for Affective Processing
Authors: Dulk Paul den , Heerebout Bram T. , Phaf R. Hans 
Published: March 2003

Abstract
The evolutionary justification by LeDoux (1996) for his dual-route model of fear processing was analyzed computationally by applying genetic algorithms to artificial neural networks. The evolution was simulated of a neural network controlling an agent that gathered food in an artificial world and that was occasionally menaced by a predator. Connections could not change in the agent's “lifetime,” so there was no learning in the simulations. Only if the smells of food and predator were hard to distinguish and the fitness reflected time pressures in escaping from the predator did the type of dual processing postulated by LeDoux emerge in the surviving agents. Processing in the “quick and dirty” pathway of the fear system ensured avoidance of both predators and food, but a distinction between food and predator was made only in the long pathway. Elaborate processing inhibited the avoidance reaction and reversed it into an approach reaction to food, but strengthened the avoidance reaction to predators (and more finely tuned the direction of escape). It is suggested that “computational neuroethology” (Beer, 1990) may help constrain reasoning in evolutionary psychology, particularly when applied to specific neurobiological models, and in the future may even generate new hypotheses for cognitive neuroscience.
Visual Selective Behavior Can Be Triggered by a Feed-Forward Process
Authors: VanRullen Rufin , Koch Christof 
Published: March 2003

Abstract
The ventral visual pathway implements object recognition and categorization in a hierarchy of processing areas with neuronal selectivities of increasing complexity. The presence of massive feedback connections within this hierarchy raises the possibility that normal visual processing relies on the use of computational loops. It is not known, however, whether object recognition can be performed at all without such loops (i.e., in a purely feed-forward mode). By analyzing the time course of reaction times in a masked natural scene categorization paradigm, we show that the human visual system can generate selective motor responses based on a single feed-forward pass. We confirm these results using a more constrained letter discrimination task, in which the rapid succession of a target and mask is actually perceived as a distractor. We show that a masked stimulus presented for only 26 msec—and often not consciously perceived—can fully determine the earliest selective motor responses: The neural representations of the stimulus and mask are thus kept separated during a short period corresponding to the feed-forward “sweep.” Therefore, feedback loops do not appear to be “mandatory” for visual processing. Rather, we found that such loops allow the masked stimulus to reverberate in the visual system and affect behavior for nearly 150 msec after the feed-forward sweep.
Enhanced Pitch Sensitivity in Individuals with Autism: A Signal Detection Analysis
Authors: Bonnel Anna , Mottron Laurent , Peretz Isabelle , Trudel Manon , Gallun Erick , Bonnel Anne-Marie 
Published: March 2003

Abstract
Past research has shown a superiority of participants with high-functioning autism over comparison groups in memorizing picture-pitch associations and in detecting pitch changes in melodies. A subset of individuals with autism, known as “musical savants,” is also known to possess absolute pitch. This superiority might be due to an abnormally high sensitivity to fine-grained pitch differences in sounds. To test this hypothesis, psychoacoustic tasks were devised so as to use a signal detection methodology. Participants were all musically untrained and were divided into a group of 12 high-functioning individuals with autism and a group of 12 normally developing individuals. Their task was to judge the pitch of pure tones in a “same-different” discrimination task and in a “high-low” categorization task. In both tasks, the obtained psychometric functions revealed higher pitch sensitivity for subjects with autism, with a more pronounced advantage over control participants in the categorization task. These findings confirm that pitch processing is enhanced in “high-functioning” autism. Superior performance in pitch discrimination and categorization extends previous findings of enhanced visual performance to the auditory domain. Thus, and as predicted by the enhanced perceptual functioning model for peaks of ability in autism (Mottron & Burack, 2001), autistic individuals outperform typically developing population in a variety of low-level perceptual tasks.
Lateralization of Prefrontal Activity during Episodic Memory Retrieval: Evidence for the Production-Monitoring Hypothesis
Authors: Cabeza Roberto , Locantore Jill K. , Anderson Nicole D. 
Published: March 2003

AbstractWe propose a new hypothesis concerning the lateralization of prefrontal cortex (PFC) activity during verbal episodic memory retrieval. The hypothesis states that the left PFC is differentially more involved in semantically guided information production than is the right PFC, and that the right PFC is differentially more involved in monitoring and verification than is the left PFC. This “production-monitoring hypothesis” differs from the existing “systematic-heuristic hypothesis,” which proposes that the left PFC is primarily involved in systematic retrieval operations, and the right PFC in heuristic retrieval operations. To compare the two hypotheses, we measured PFC activity using positron emission tomography (PET) during the performance of four episodic retrieval tasks: stem cued recall, associative cued recall, context recognition (source memory), and item recognition. Recall tasks emphasized production processes, whereas recognition tasks emphasized monitoring processes. Stem cued recall and context-recognition tasks underscored systematic operations, whereas associative cued recall and item-recognition tasks underscored heuristic operations. Consistent with the production-monitoring hypothesis, the left PFC was more activated for recall than for recognition tasks and the right PFC was more activated for recognition than for recall tasks. Inconsistent with the systematic-heuristic hypothesis, the left PFC was more activated for heuristic than for systematic tasks and the right PFC showed the converse result. Additionally, the study yielded activation differences outside the PFC. In agreement with a previous recall/recognition PET study, anterior cingulate, cerebellar, and striatal regions were more activated for recall than for recognition tasks, and the converse occurred for posterior parietal regions. A right medial temporal lobe region was more activated for stem cued recall and context recognition than for associative cued recall and item recognition, possibly reflecting perceptual integration. In sum, the results provide evidence for the production-monitoring hypothesis and clarify the role of different brain regions typically activated in PET and functional magnetic resonance imaging (fMRI) studies of episodic retrieval.
Distinct Patterns of Neural Modulation during the Processing of Conceptual and Syntactic Anomalies
Authors: Kuperberg Gina R. , Holcomb Phillip J. , Sitnikova Tatiana , Greve Douglas , Dale Anders M. , Caplan David 
Published: March 2003

Abstract
The aim of this study was to gain further insights into how the brain distinguishes between meaning and syntax during language comprehension. Participants read and made plausibility judgments on sentences that were plausible, morpho-syntactically anomalous, or pragmatically anomalous. In an event-related potential (ERP) experiment, morphosyntactic and pragmatic violations elicited significant P600 and N400 effects, respectively, replicating previous ERP studies that have established qualitative differences in processing conceptually and syntactic anomalies. Our main focus was a functional magnetic resonance imaging (fMRI) study in which the same subjects read the same sentences presented in the same pseudorandomized sequence while performing the same task as in the ERP experiment. Rapid-presentation event-related fMRI methods allowed us to estimate the hemodynamic response at successive temporal windows as the sentences unfolded word by word, without assumptions about the shape of the underlying response function. Relative to nonviolated sentences, the pragmatic anomalies were associated with an increased hemodynamic response in left temporal and inferior frontal regions and a decreased response in the right medial parietal cortex. Relative to nonviolated sentences, the morphosyntactic anomalies were associated with an increased response in bilateral medial and lateral parietal regions and a decreased response in left temporal and inferior frontal regions. Thus, overlapping neural networks were modulated in opposite directions to the two types of anomaly. These fMRI findings document both qualitative and quantitative differences in how the brain distinguishes between these two types of anomalies. This suggests that morphosyntactic and pragmatic information can be processed in different ways but by the same neural systems.
Aristotelian Piety
Authors: Broadie Sarah 
Published: March 2003

AbstractAristotle seems to omit discussing the virtue piety. Such an omission should surprise us. Piety is not covertly dealt with under the more general heading of justice, nor under that of philia. But piety does make a veiled appearance at NE X.8, 1179a22-32. Many interpreters have refused to take this passage seriously, but this is shown to be a mistake.
On the turning ofXenopusretinal axons induced by ephrin-A5
Authors: Weinl Christine , Drescher Uwe , Lang Susanne , Bonhoeffer Friedrich , Löschinger Jürgen 
Published: March 2003

The Eph family of receptor tyrosine kinases and their ligands, the ephrins,play important roles during development of the nervous system. Frequently they exert their functions through a repellent mechanism, so that, for example, an axon expressing an Eph receptor does not invade a territory in which an ephrin is expressed. Eph receptor activation requires membrane-associated ligands. This feature discriminates ephrins from other molecules sculpturing the nervous system such as netrins, slits and class 3 semaphorins, which are secreted molecules. While the ability of secreted molecules to guide axons,i.e. to change their growth direction, is well established in vitro, little is known about this for the membrane-bound ephrins. Here we set out to investigate – using Xenopus laevis retinal axons – the properties of substratum-bound and (artificially) soluble forms of ephrin-A5(ephrin-A5-Fc) to guide axons.We find – as expected on the basis of chick experiments – that,when immobilised in the stripe assay, ephrin-A5 has a repellent effect such that retinal axons avoid ephrin-A5-Fc-containing lanes. Also, retinal axons react with repulsive turning or growth cone collapse when confronted with ephrin-A5-Fc bound to beads. However, when added in soluble form to the medium, ephrin-A5 induces growth cone collapse, comparable to data from chick.The analysis of growth cone behaviour in a gradient of soluble ephrin-A5 in the `turning assay' revealed a substratum-dependent reaction ofXenopus retinal axons. On fibronectin, we observed a repulsive response, with the turning of growth cones away from higher concentrations of ephrin-A5. On laminin, retinal axons turned towards higher concentrations,indicating an attractive effect. In both cases the turning response occurred at a high background level of growth cone collapse. In sum, our data indicate that ephrin-As are able to guide axons in immobilised bound form as well as in the form of soluble molecules. To what degree this type of guidance is relevant for the in vivo situation remains to be shown.
Generating globally optimised sagittal gait cycles of a biped robot
Authors: Saidouni Tarik , Bessonnet Guy 
Published: March 2003

The paper is aimed at generating optimal gait cycles in the sagittal plane of a biped, the locomotion system of which has anthropomorphic characteristics. Both single and double support phases are globally optimised, considering incompletely specified transition postural configurations from one phase to the other. An impactless heel-touch is prescribed. Full dynamic models are developed for both gait phases. They are completed by specific constraints attached to the unilaterality of contact with the supporting
ground.A parametric optimisation method is implemented. The biped joint coordinates are approximated by cubic splines functions connected at uniformly distributed knots along the motion time. The finite set of unknowns consists of the joint coordinate values at knots, some gait pattern parameters at phase transitions, and the motion time of each phase. The step length is adjusted to the prescribed gait speed by the optimisation process. Numerical simulations concerning slow and fast optimal gaits are presented and discussed.
A joint trajectory generator for motion recovery
Authors: Li Wei , Red Edward 
Published: March 2003

This paper describes an adaptive S-curve used to recover a tool path upon a system crash in the Windows operating system (OS). For a mechanism such as a robot or machine tool, the joint values, being delivered as setpoints to the servo-controller, are dynamically recorded by the real-time operating system also residing on the computer. The real-time OS can control the abort and record pertinent motion data after Windows OS crash.Upon system recovery, the recovery trajectory generator examines the setpoints intervals to determine the current slow joint. At every trajectory step, and for the current slow joint, the S-curve velocity profile applies the joint entry state (position, speed, acceleration, and jerk) to interpolate the motion between the setpoints in a reverse direction. The other joints are proportionally interpolated (slowed) so that they pass through each setpoint simultaneously with the slow joint, but in a reverse direction.The trajectory algorithm is optimal since the slow joint always uses the maximum allowable jerk to change the profile speed and acceleration for each trajectory step.
Sensitization to allergens of house‐dust mite in adults with atopic dermatitis in a cold temperate region
Authors: Holm L , Öhman S , Van Hage‐hamsten M , Scheynius A 
Published: March 2003

Background: An IgE‐mediated contact reaction to airborne allergens has been suggested as one important pathogenetic mechanism in atopic dermatitis (AD). The house‐dust mite (HDM) might be a common allergen involved. In Scandinavia, sensitization to HDM has been rare, probably because of the cold, dry climate. However, recent studies indicate high levels of domestic mites and HDM allergen in 15–20% of homes in central and northern Sweden. Methods: To evaluate the importance of the HDM in patients with AD in the Stockholm region, we screened 81 adult Stockholm residents with AD, for the prevalence and degree of sensitization to the HDM, according to specific IgE (RAST), skin prick test (SPT), and atopy patch test (APT). We also assessed the HDM exposure in their homes and correlated the results with clinical history, severity of the dermatitis, and type of residence during childhood and today. Results: The sensitization rate to HDM was high (56% according to RAST, 24% according to SPT, and 47% according to APT), and 20% of the patients were exposed to HDM allergens in their beds. Mite exposure seemed to aggravate the dermatitis in highly sensitized patients. Conclusions: The results indicate that we have to take the HDM into account when discussing aggravating factors in adult patients with AD in the Stockholm region.