CiteULike: Author Spence

FAB: building distributed enterprise disk arrays from commodity components

Yasushi Saito — 2008-07-22T02:23:56-00:00

SIGOPS Oper. Syst. Rev., Vol. 38, No. 5. (December 2004), pp. 48-58.

Task-at-hand interface for change detection in stock market data

Carmen Merino — 2008-07-17T12:02:23-00:00

(2006), pp. 420-427.

X-ray imaging: Ultrafast diffract-and-destroy movies

John Spence — 2008-07-17T05:38:01-00:00

Nat Photon, Vol. 2, No. 7. (July 2008), pp. 390-391.

RSVP Browser: Web Browsing on Small Screen Devices

O de Bruijn — 2008-07-14T18:46:26-00:00

Personal and Ubiquitous Computing, Vol. 6, No. 4. (2002), pp. 245-252.

Abstract: In this paper, we illustrate the use of space-time trade-offs for information presentation on small screens. We propose the use of Rapid Serial Visual Presentation (RSVP) to provide a rich set of navigational information for Web browsing. The principle of RSVP browsing is applied to the development of a Web browser for small screen devices, the RSVP browser. The results of an experiment in which Web browsing with the RSVP browser is compared with that of a typical WAP browser suggests that RSVP browsing may indeed offer alternative to other forms of Web browsing on small screen devices.

Carotid endarterectomy - An evidence-based review: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

S Chaturvedi — 2008-07-12T20:05:38-00:00

Neurology, Vol. 65, No. 6. (2005), pp. 794-801.

Objective: To assess the efficacy of carotid endarterectomy for stroke prevention in asymptomatic and symptomatic patients with internal carotid artery stenosis. Additional clinical scenarios, such as use of endarterectomy combined with cardiac surgery, are also reviewed. Methods: The authors selected nine important clinical questions. A systematic search was performed for articles from 1990 (the year of the last statement) until 2001. Additional articles from 2002 through 2004 were included using prespecified criteria. Two reviewers also screened for other relevant articles from 2002 to 2004. Case reports, review articles, technical studies, and single surgeon case series were excluded. Results: For several questions, high quality randomized clinical trials had been completed. Carotid endarterectomy reduces the stroke risk compared to medical therapy alone for patients with 70 to 99% symptomatic stenosis (16% absolute risk reduction at 5 years). There is a smaller benefit for patients with 50 to 69% symptomatic stenosis (absolute risk reduction 4.6% at 5 years). There is a small benefit for asymptomatic patients with 60 to 99% stenosis if the perioperative complication rate is low. Aspirin in a dose of 81 to 325 mg per day is preferred vs higher doses (650 to 1,300 mg per day) in patients undergoing endarterectomy. Conclusions: Evidence supports carotid endarterectomy for severe (70 to 99%) symptomatic stenosis (Level A). Endarterectomy is moderately useful for symptomatic patients with 50 to 69% stenosis (Level B) and not indicated for symptomatic patients with <50% stenosis (Level A). For asymptomatic patients with 60 to 99% stenosis, the benefit/risk ratio is smaller compared to symptomatic patients and individual decisions must be made. Endarterectomy can reduce the future stroke rate if the perioperative stroke/death rate is kept low (<3%) (Level A). Low dose aspirin (81 to 325 mg) is preferred for patients before and after carotid endarterectomy to reduce the rate of stroke, myocardial infarction, and death (Level A). Copyright © 2005 by AAN Enterprises, Inc.

Life Beyond the Mailbox: Cross-Tool Perspective On Personal Information Management

Richard Boardman — 2007-07-04T02:55:02-00:00

Email interfaces provide poor support for the personal information management (PIM) activities that users have adopted them for. This paper reports a user study that highlights how two aspects of PIM, information management and task management, cut across a range of tools, including email. We argue that effective support for such cross-tool activities cannot be provided through a focus on one interface - such as email - alone. Instead, a cross-tool approach is needed in PIM-related research ...

Four-point Amplitudes in N=8 Supergravity and Wilson Loops

Andreas Brandhuber — 2008-07-10T07:53:45-00:00

(9 Jul 2008)

Prompted by recent progress in the study of N=4 super Yang-Mills amplitudes, and evidence that similar approaches might be relevant to N=8 supergravity, we investigate possible iterative structures and applications of Wilson loop techniques in maximal supergravity. We first consider the two-loop, four-point MHV scattering amplitude in N=8 supergravity, confirming that the infrared divergent parts exponentiate, and we give the explicit expression which represents the failure for this to occur for the finite part. We observe that each term in the expansion of the one- and two-loop amplitudes in the dimensional regularisation parameter epsilon has a uniform degree of transcendentality. We then turn to consider Wilson loops in supergravity, showing that a natural definition of the loop, involving the Christoffel connection, fails to reproduce the one-loop amplitude. An alternative expression, which involves the metric explicitly, is shown to have a close relationship with the physical amplitude. We find that in a gauge in which the cusp diagrams vanish, the remaining diagrams for this Wilson loop correctly generate the full one-loop, four-point N=8 supergravity amplitude.

Playing an Action Video Game Reduces Gender Differences in Spatial Cognition

Feng — 2007-10-11T18:08:52-00:00

Psychological Science, Vol. 18, No. 10. (October 2007), pp. 850-855.

The Sensitivity of the Atlantic Meridional Overturning Circulation to Freshwater Forcing at Eddy-Permitting Resolutions

Paul Spence — 2008-06-20T08:43:36-00:00

Journal of Climate, Vol. 21, No. 11. (1 June 2008), pp. 2697-2710.

The effect of increasing horizontal resolution is examined to assess the response of the Atlantic meridional overturning circulation (AMOC) to freshwater perturbations. Versions of a global climate model with horizontal resolutions ranging from 1.8° (latitude) × 3.6° (longitude) to 0.2° × 0.4° are used to determine if the AMOC response to freshwater forcing is robust to increasing resolution. In the preindustrial equilibrium climate, the representation of western boundary currents and meridional heat transport are improved with resolution. Freshwater forcings similar to the final drainage of proglacial Lakes Agassiz and Ojibway are applied evenly over the Labrador Sea and exclusively along the western boundary. The duration and maximum amplitude of model responses to freshwater forcing showed little sensitivity to increasing resolution. An evaluation with tracers of the forcing impact on different regions of North Atlantic Deep Water formation revealed the possibility that increases in Labrador Sea deep convection at higher resolution mitigate the effect of stronger boundary currents and enhanced mixing. With increasing resolution, there is less cooling in the subpolar west Atlantic, more cooling in the subpolar east Atlantic, and greater variability in the deep ocean response to the boundary forcing. While differences exist, the coarse-resolution model response remains robust at finer horizontal resolutions.

Using spatial vibrotactile cues to direct visual attention in driving scenes

Cristy Ho — 2008-07-04T07:41:13-00:00

Transportation Research Part F: Traffic Psychology and Behaviour, Vol. 8, No. 6. (November 2005), pp. 397-412.

We report two experiments designed to investigate the potential use of vibrotactile warning signals to present spatial information to car drivers. Participants performed an attention-demanding rapid serial visual presentation (RSVP) monitoring task. Meanwhile, whenever they felt a vibrotactile stimulus presented on either their front or back, they had to check the front and the rearview mirror for the rapid approach of a car, and brake or accelerate accordingly. We investigated whether speeded responses to potential emergency driving situations could be facilitated by the presentation of spatially-predictive (80% valid; Experiment 1) or spatially-nonpredictive (50% valid; Experiment 2) vibrotactile cues. Participants responded significantly more rapidly following both spatially-predictive and spatially-nonpredictive vibrotactile cues from the same rather than the opposite direction as the critical driving events. These results highlight the potential utility of vibrotactile warning signals in automobile interface design for directing a driver's visual attention to time-critical events or information.

Dopamine genes and ADHD.

JM Swanson — 2008-06-22T15:26:08-00:00

Neuroscience and biobehavioral reviews, Vol. 24, No. 1. (January 2000), pp. 21-25.

Family, twin, and adoption studies have documented a strong genetic basis for ADHD/HKD, but these studies do not identify specific genes linked to the disorder. Molecular genetic studies can identify allelic variations of specific genes that are functionally associated with ADHD/HKD, and dopamine genes have been the initial candidates based on the site of action of the stimulants drugs, which for a half century have provided the primary pharmacological treatment for ADHD/HKD. Two candidate dopamine genes have been investigated and reported to be associated with ADHD/HKD: the dopamine transporter (DAT1) gene [Cook et al., American Journal of Human Genetics 1995;56:993-998, Gill et al., Molecular Psychiatry 1997;2:311-313] and the dopamine receptor D4 (DRD4) gene [LaHoste et al., Molecular Psychiatry 1996;1:121-124: Smalley et al., 1998;3:427-430; Swanson et al., Molecular Psychiatry 1998;3:38-41]. Speculative hypotheses [Swanson and Castellanos, NIH Consensus Development Conference: Diagnosis and Treatment of Attention Deficit Hyperactivity Disorder, November 1998. p. 37-42] have suggested that specific alleles of these dopamine genes may alter dopamine transmission in the neural networks implicated in ADHD/HKD (e.g. that the 10-repeat allele of the DAT1 gene may be associated with hyperactive re-uptake of dopamine or that the 7-repeat allele of the DRD4 gene may be associated with a subsensitive postsynaptic receptor). These and other variants of the dopamine hypothesis of ADHD will be discussed.

Tutorial in biostatistics: Analyzing associations between total plasma homocysteine and B vitamins using optimal categorization and segmented regression.

H Bang — 2008-06-18T15:23:34-00:00

Neuroepidemiology, Vol. 27, No. 4. (2006), pp. 188-200.

Data analysts consider standard regression models (e.g., generalized linear model) or nonparametric smoothing techniques (e.g., loess or splines) when examining the association between two variables. Before this step, a quantile-based summarization is typically used for exploring the exposure-response relationship. Unfortunately, these exploratory approaches may not be optimal or efficient for guiding the formal analysis in many biological and nutritional data settings. We suggest a recently developed method for selection of cutpoints as a tool of data summary and segmented regression as a modeling approach in the analysis of plasma total homocysteine and related vitamins. These methods are often complementary in discovering the underlying complex pattern of association.

Looking for truth and finding lies: The prospects for a nascent neuroimaging of deception

Sean Spence — 2008-06-17T05:11:13-00:00

Neurocase, Vol. 14, No. 1. (2008), pp. 68-81.

Lying is ubiquitous and has acquired many names. In natural experiments, both pathological lying and truthfulness implicate prefrontal cortices. Recently, the advent of functional neuroimaging has allowed investigators to study deception in the non-pathological state. Prefrontal cortices are again implicated, although the regions identified vary across experiments. Forensic application of such technology (to the detection of deceit) requires the solution of tractable technical problems. Whether we should detect deception remains an ethical problem: one for societies to resolve. However, such a procedure would only appear to be ethical when subjects volunteer to participate, as might occur during the investigation of alleged miscarriages of justice. We demonstrate how this might be approached.

The systems biology markup language (SBML): a medium for representation and exchange of biochemical network models.

M Hucka — 2004-11-22T00:17:30-00:00

Bioinformatics, Vol. 19, No. 4. (1 March 2003), pp. 524-531.

MOTIVATION: Molecular biotechnology now makes it possible to build elaborate systems models, but the systems biology community needs information standards if models are to be shared, evaluated and developed cooperatively. RESULTS: We summarize the Systems Biology Markup Language (SBML) Level 1, a free, open, XML-based format for representing biochemical reaction networks. SBML is a software-independent language for describing models common to research in many areas of computational biology, including cell signaling pathways, metabolic pathways, gene regulation, and others. AVAILABILITY: The specification of SBML Level 1 is freely available from http://www.sbml.org/

Optimising the precision for localising fluorescent proteins in living cells by 2D Gaussian fitting of digital images: application to COPII-coated endoplasmic reticulum exit sites.

Peter Spence — 2008-06-15T21:28:02-00:00

European biophysics journal : EBJ (27 May 2008)

An insight into the operation of molecular motors has already been obtained under in vitro conditions from single-molecule tracking of proteins. It remains to analyse the effects of these motors on the position and secretion of specific organelles in the environment of the cell. For this purpose, we have investigated the accuracy of a standard algorithm to enable the tracking of particles in live-cell microscopy. The results have been applied to an example study into the role of the microtubule-motor kinesin on the function of COPII-coated secretory-cargo exit sites forming part of the mammalian endoplasmic reticulum. These exit sites are marked with multiple EYFP-tagged proteins to produce bright fluorescent particles, and a demonstration of the motility of vesicles, under different conditions in the cell, is described here. It is essential to use a low-level expression of fluorescent protein-tagged cellular components to ensure faithful replication for the behaviour of endogenous protein. However, this leads to a lower ratio for the signal-to-noise than is desired for the sub-pixel tracking of objects in digital images. This has driven the present effort to develop a computational model of the experiment in order to estimate the precision for localization of a fluorescent particle. Our work gives a greater insight, than has been managed in the past, into the accuracy and precision of particle tracking from live-cell imaging under a variety of different conditions, and it takes into consideration the current standards in digital technology for optical microscopy.

Capturing spatial attention with multisensory cues.

V Santangelo — 2008-06-13T19:00:48-00:00

Psychonomic bulletin & review, Vol. 15, No. 2. (April 2008), pp. 398-403.

We assessed the influence ofmultisensory interactions on the exogenous orienting of spatial attention by comparing the ability of auditory, tactile, and audiotactile exogenous cues to capture visuospatial attention under conditions of no perceptual load versus high perceptual load. In Experiment 1, participants discriminated the elevation of visual targets preceded by either unimodal or bimodal cues under conditions of either a high perceptual load (involving the monitoring of a rapidly presented central stream of visual letters for occasionally presented target digits) or no perceptual load (when the central stream was replaced by a fixation point). All of the cues captured spatial attention in the no-load condition, whereas only the bimodal cues captured visuospatial attention in the high-load condition. In Experiment 2, we ruled out the possibility that the presentation of any changing stimulus at fixation (i.e., a passively monitored stream of letters) would eliminate exogenous orienting, which instead appears to be a consequence of high perceptual load conditions (Experiment 1). These results demonstrate that multisensory cues capture spatial attention more effectively than unimodal cues under conditions of concurrent perceptual load.

Minimum information requested in the annotation of biochemical models (MIRIAM)

Nicolas Le Novère — 2005-12-06T22:36:05-00:00

Nature Biotechnology, Vol. 23, No. 12. (06 December 2005), pp. 1509-1515.

Cross-Modal Interactions Between Olfaction and Touch

Dematte — 2006-05-09T01:42:42-00:00

Chemical Senses, Vol. 31, No. 4. (May 2006), pp. 291-300.

Vision and touch through the looking glass in a case of crossmodal extinction.

A Maravita — 2008-03-12T08:16:15-00:00

Neuroreport, Vol. 11, No. 16. (9 November 2000), pp. 3521-3526.

When observing ourselves in a mirror, we see our body and adjacent objects (e.g. a comb or razor) projecting the image of distant objects. Are these recoded by the brain as reflecting stimuli in peripersonal space? To address this, we exploited the neuropsychological phenomenon of crossmodal, visual-tactile extinction, as shown by patient BV following right-hemisphere stroke. In such crossmodal extinction, a right visual event impairs the perception of a simultaneous left tactile event. In BV, the right visual stimulus (an LED flash) induced more extinction of touch on the contralesional left hand when presented near the ipsilesional right hand, than when distant from it. This agrees with previous data in patients and monkeys showing that visual-tactile interactions are strongest within peripersonal space. Crucially, we also found that an ipsilesional flash produced more extinction when observed as the distant mirror-reflection of an LED that lay close to the ipsilesional hand, rather than as a distant LED flash projecting an equivalent visual image directly. This suggests that in BV, seeing his own hand via a mirror activates a representation of peripersonal space around that hand, not of the extrapersonal space suggested by the distant visual image in the mirror. We discuss the possible neural basis of interpreting mirror reflections.

On the inability to ignore touch when responding to vision in the crossmodal congruency task

Charles Spence — 2005-10-08T04:45:15-00:00

Acta Psychologica, Vol. 118, No. 1-2. ( 2005), pp. 47-70.

We investigated the extent to which people can selectively ignore distracting vibrotactile information when performing a visual task. In Experiment 1, participants made speeded elevation discrimination responses (up vs. down) to a series of visual targets presented from one of two eccentricities on either side of central fixation, while simultaneously trying to ignore task-irrelevant vibrotactile distractors presented independently to the finger (up) vs. thumb (down) of either hand. Participants responded significantly more slowly, and somewhat less accurately, when the elevation of the vibrotactile distractor was incongruent with that of the visual target than when they were presented from the same (i.e., congruent) elevation. This crossmodal congruency effect was significantly larger when the visual and tactile stimuli appeared on the same side of space than when they appeared on different sides, although the relative eccentricity of the two stimuli within the hemifield (i.e., same vs. different) had little effect on performance. In Experiment 2, participants who crossed their hands over the midline showed a very different pattern of crossmodal congruency effects to participants who adopted an uncrossed hands posture. Our results suggest that both the relative external location and the initial hemispheric projection of the target and distractor stimuli contribute jointly to determining the magnitude of the crossmodal congruency effect when participants have to respond to vision and ignore touch.

The cognitive and neural correlates of "tactile consciousness": A multisensory perspective

Alberto Gallace — 2008-03-22T05:40:18-00:00

Consciousness and Cognition, Vol. 17, No. 1. (March 2008), pp. 370-407.

People's awareness of tactile stimuli has been investigated in far less detail than their awareness of stimuli in other sensory modalities. In an attempt to fill this gap, we provide an overview of studies that are pertinent to the topic of tactile consciousness. We discuss the results of research that has investigated phenomena such as "change blindness", phantom limb sensations, and numerosity judgments in tactile perception, together with the results obtained from the study of patients affected by deficits that can adversely affect tactile perception such as neglect, extinction, and numbsense. The similarities as well as some of the important differences that have emerged when visual and tactile conscious information processing have been compared using similar experimental procedures are highlighted. We suggest that conscious information processing in the tactile modality cannot be separated completely from the more general processing of spatial information in the brain. Finally, the importance of considering tactile consciousness within the larger framework of multisensory information processing is also discussed.

Application of business case analysis in planning a province-wide telehealth network in Alberta

L Weaver — 2008-05-28T18:24:09-00:00

(February 2000)

A strategy for implementing telemedicine throughout Alberta was developed. The model was based on a comprehensive evaluation of the four clinical specialties chosen as representative telemedicine services - radiology, psychiatry, emergency services and continuing education. The goals of the telemedicine network were to improve access to health services, provide support for rural health-care providers and increase the efficiency of specialized services. The findings showed that the success factors in a national telemedicine programme depend on a clear organizational structure, with appropriate technical standards and support.

Multisensory contributions to the perception of motion

Salvador Soto-Faraco — 2008-05-27T16:38:16-00:00

Neuropsychologia, Vol. 41, No. 13. (2003), pp. 1847-1862.

The ability to process motion is crucial for coherent perception and action. While the majority of studies have focused on the unimodal factors that influence motion perception (see, for example, the other chapters in this Special Issue), some researchers have also investigated the extent to which information presented in one sensory modality can affect the perception of motion for stimuli presented in another modality. Although early studies often gave rise to mixed results, the development of increasingly sophisticated psychophysical paradigms are now enabling researchers to determine the spatiotemporal constraints on multisensory interactions in the perception of motion. Recent findings indicate that these interactions stand over-and-above the multisensory interactions documented previously for static stimuli, such as the oft-cited [`]ventriloquism' effect. Neuroimaging and neuropsychological studies are also beginning to elucidate the network of neural structures responsible for the processing of motion information in the different sensory modalities, an important first step that will ultimately lead to the determination of the neural substrates underlying these multisensory contributions to motion perception.

Exposure to asynchronous audiovisual speech extends the temporal window for audiovisual integration

Jordi Navarra — 2008-05-27T16:18:30-00:00

Cognitive Brain Research, Vol. 25, No. 2. (October 2005), pp. 499-507.

We examined whether monitoring asynchronous audiovisual speech induces a general temporal recalibration of auditory and visual sensory processing. Participants monitored a videotape featuring a speaker pronouncing a list of words (Experiments 1 and 3) or a hand playing a musical pattern on a piano (Experiment 2). The auditory and visual channels were either presented in synchrony, or else asynchronously (with the visual signal leading the auditory signal by 300 ms; Experiments 1 and 2). While performing the monitoring task, participants were asked to judge the temporal order of pairs of auditory (white noise bursts) and visual stimuli (flashes) that were presented at varying stimulus onset asynchronies (SOAs) during the session. The results showed that, while monitoring desynchronized speech or music, participants required a longer interval between the auditory and visual stimuli in order to perceive their temporal order correctly, suggesting a widening of the temporal window for audiovisual integration. The fact that no such recalibration occurred when we used a longer asynchrony (1000 ms) that exceeded the temporal window for audiovisual integration (Experiment 3) supports this conclusion.

Auditory motion affects visual motion perception in a speeded discrimination task

Sanabria — 2007-04-20T06:46:41-00:00

Experimental Brain Research, Vol. 178, No. 3. (April 2007), pp. 415-421.

Multisensory prior entry.

C Spence — 2006-02-09T10:23:21-00:00

J Exp Psychol Gen, Vol. 130, No. 4. (December 2001), pp. 799-832.

Despite 2 centuries of research, the question of whether attending to a sensory modality speeds the perception of stimuli in that modality has yet to be resolved. The authors highlight weaknesses inherent in this previous research and report the results of 4 experiments in which a novel methodology was used to investigate the effects on temporal order judgments (TOJs) of attending to a particular sensory modality or spatial location. Participants were presented with pairs of visual and tactile stimuli from the left and/or right at varying stimulus onset asynchronies and were required to make unspeeded TOJs regarding which stimulus appeared first. The results provide the strongest evidence to date for the existence of multisensory prior entry and support previous claims for attentional biases toward the visual modality and toward the right side of space. These findings have important implications for studies in many areas of human and animal cognition.

Visual Prior Entry

David Shore — 2008-05-27T15:51:00-00:00

Psychological Science, Vol. 12, No. 3. (2001), pp. 205-212.

It has long been claimed that attended stimuli are perceived prior to unattended stimuli-the doctrine of prior entry. Most, if not all, studies on which such claims have been based, however, are open to a nonattentional interpretation involving response bias, leading some researchers to assert that prior entry may not exist. Given this controversy, we introduce a novel methodology to minimize the effect of response bias by manipulating attention and response demands in orthogonal dimensions. Attention was oriented to the left or right (i.e., spatially), but instead of reporting on the basis of location, observers reported the order (first or second) of vertical versus horizontal line segments. Although second-order response biases were demonstrated, effects of attention in accordance with the law of prior entry were clearly obtained following both exogenous and endogenous attentional cuing.

The hedgehog pathway is a modulator of retina regeneration

Jason Spence — 2008-05-13T15:43:50-00:00

Development, Vol. 131, No. 18. (15 September 2004), pp. 4607-4621.

The embryonic chick has the ability to regenerate its retina after it has been completely removed. Here, we provide a detailed characterization of retina regeneration in the embryonic chick at the cellular level. Retina regeneration can occur in two distinct manners. The first is via transdifferentiation, which is induced by members of the Fibroblast growth factor (Fgf) family. The second type of retinal regeneration occurs from the anterior margin of the eye, near the ciliary body (CB) and ciliary marginal zone (CMZ). We show that regeneration from the CB/CMZ is the result of proliferating stem/progenitor cells. This type of regeneration is also stimulated by Fgf2, but we show that it can be activated by Sonic hedgehog (Shh) overexpression when no ectopic Fgf2 is present. Shh-stimulated activation of CB/CMZ regeneration is inhibited by the Fgf receptor (Fgfr) antagonist, PD173074. This indicates that Shh-induced regeneration acts through the Fgf signaling pathway. In addition, we show that the hedgehog (Hh) pathway plays a role in maintenance of the retina pigmented epithelium (RPE), as ectopic Shh expression inhibits transdifferentiation and Hh inhibition increases the transdifferentiation domain. Ectopic Shh expression in the regenerating retina also results in a decrease in the number of ganglion cells present and an increase in apoptosis mostly in the presumptive ganglion cell layer (GCL). However, Hh inhibition increases the number of ganglion cells but does not have an effect on cell death. Taken together, our results suggest that the hedgehog pathway is an important modulator of retina regeneration. 10.1242/dev.01298

Melatonin, environmental light, and breast cancer

V Srinivasan — 2008-05-10T01:58:41-00:00

Breast Cancer Research and Treatment, Vol. 108, No. 3. (20 April 2008), pp. 339-350.

Abstract Although many factors have been suggested as causes for breast cancer, the increased incidence of the disease seen in women working in night shifts led to the hypothesis that the suppression of melatonin by light or melatonin deficiency plays a major role in cancer development. Studies on the 7,12-dimethylbenz[a]anthracene and N-methyl-N-nitrosourea experimental models of human breast cancer indicate that melatonin is effective in reducing cancer development. In vitro studies in MCF-7 human breast cancer cell line have shown that melatonin exerts its anticarcinogenic actions through a variety of mechanisms, and that it is most effective in estrogen receptor (ER) α-positive breast cancer cells. Melatonin suppresses ER gene, modulates several estrogen dependent regulatory proteins and pro-oncogenes, inhibits cell proliferation, and impairs the metastatic capacity of MCF-7 human breast cancer cells. The anticarcinogenic action on MCF-7 cells has been demonstrated at the physiological concentrations of melatonin attained at night, suggesting thereby that melatonin acts like an endogenous antiestrogen. Melatonin also decreases the formation of estrogens from androgens via aromatase inhibition. Circulating melatonin levels are abnormally low in ER-positive breast cancer patients thereby supporting the melatonin hypothesis for breast cancer in shift working women. It has been postulated that enhanced endogenous melatonin secretion is responsible for the beneficial effects of meditation as a form of psychosocial intervention that helps breast cancer patients.

Bouncing or streaming? Exploring the influence of auditory cues on the interpretation of ambiguous visual motion

Daniel Sanabria — 2008-05-04T22:39:21-00:00

Experimental Brain Research, Vol. 157, No. 4. (2004), pp. 537-541.

When looking at two identical objects moving toward each other on a two-dimensional visual display, two different events can be perceived: the objects can either be seen to bounce off each other, or else to stream through one another. Previous research has shown that the large bias normally seen toward the streaming percept can be modulated by the presentation of an auditory event at the moment of coincidence. However, previous behavioral research on this crossmodal effect has always relied on subjective report. In the present experiment, we used a novel experimental design to provide a more objective/implicit measure of the effect of an auditory cue on visual motion perception. In our study, two disks moved toward each other, with the point of coincidence hidden behind an occluder. When emerging from behind the occluder, the disks (one red, the other blue) could either follow the same trajectory (streaming) or else move in the opposite direction (bouncing). Participants made speeded discrimination responses regarding the side from which one of the disks emerged from behind the occluder. Participants responded more rapidly on streaming trials when no sound was presented and on bouncing trials when the sound was presented at the moment of coincidence. These results provide the first empirical demonstration of the auditory modulation of an ambiguous visual motion display using an implicit/objective behavioral measure of perception.

Regional anesthesia meets ultrasound: a specialty in transition

BD Sites — 2008-03-18T04:25:18-00:00

Acta Anaesthesiologica Scandinavica, Vol. 52, No. 4. (April 2008), pp. 456-466.

Despite its well-known benefits, regional anesthesia has not attained the stature, simplicity, and safety of general anesthesia. Many of the challenges and clinical failures of regional anesthetic techniques can be attributed to fact that neurovascular anatomy is highly variable. Furthermore, current nerve localization techniques provide little or no information regarding the anatomical spread local anesthesia. Recently, ultrasound technology has been utilized by anesthesiologists in an attempt to minimize many of the drawbacks of traditional nerve block techniques. This review article will update the reader on the current status of ultrasound-guided regional anesthesia, provide an evidence-based context, and supply key facts regarding ultrasound physics. In the process, we will also highlight several possible limitations of ultrasound techniques including learning curve issues, costs, and artifact generation.

The co-occurrence of multisensory competition and facilitation

Scott Sinnett — 2008-04-19T03:35:04-00:00

Acta Psychologica, Vol. 128, No. 1. (May 2008), pp. 153-161.

Previous studies of multisensory integration have often stressed the beneficial effects that may arise when information concerning an event arrives via different sensory modalities at the same time, as, for example, exemplified by research on the redundant target effect (RTE). By contrast, studies of the Colavita visual dominance effect (e.g., [Colavita, F. B. (1974). Human sensory dominance. Perception & Psychophysics, 16, 409-412]) highlight the inhibitory consequences of the competition between signals presented simultaneously in different sensory modalities instead. Although both the RTE and the Colavita effect are thought to occur at early sensory levels and the stimulus conditions under which they are typically observed are very similar, the interplay between these two opposing behavioural phenomena (facilitation vs. competition) has yet to be addressed empirically. We hypothesized that the dissociation may reflect two of the fundamentally different ways in which humans can perceive concurrent auditory and visual stimuli. In Experiment 1, we demonstrated both multisensory facilitation (RTE) and the Colavita visual dominance effect using exactly the same audiovisual displays, by simply changing the task from a speeded detection task to a speeded modality discrimination task. Meanwhile, in Experiment 2, the participants exhibited multisensory facilitation when responding to visual targets and multisensory inhibition when responding to auditory targets while keeping the task constant. These results therefore indicate that both multisensory facilitation and inhibition can be demonstrated in reaction to the same bimodal event.

The role of sulfur in chemical weathering and atmospheric CO2 fluxes: Evidence from major ions, [delta]13CDIC, and [delta]34SSO4 in rivers of the Canadian Cordillera

Jody Spence — 2008-04-08T16:21:48-00:00

Geochimica et Cosmochimica Acta, Vol. 69, No. 23. (1 December 2005), pp. 5441-5458.

Water samples from the Fraser, Skeena and Nass River basins of the Canadian Cordillera were analyzed for dissolved major element concentrations (HCO3-, SO42-, Cl-, Ca2+, Mg2+, K+, Na+), [delta]13C of dissolved inorganic carbon ([delta]13CDIC), and [delta]34S of dissolved sulfate ([delta]34SSO4) to quantify chemical weathering rates and exchanges of CO2 between the atmosphere, hydrosphere, and lithosphere. Weathering rates of silicates and carbonates were determined from major element mass balance. Combining the major element mass balance with [delta]34SSO4 (-8.9 to 14.1[per mille sign]CDT) indicates sulfide oxidation (sulfuric acid production) and subsequent weathering of carbonate and to a lesser degree silicate minerals are important processes in the study area. We determine that on average, 81% of the riverine sulfate can be attributed to sulfide oxidation in the Cordilleran rivers, and that 25% of the total weathering cation flux can be attributed to carbonate and silicate dissolution by sulfuric acid. This result is validated by [delta]13CDIC values (-9.8 to -3.7[per mille sign] VPDB) which represents a mixture of DIC produced by the following weathering pathways: (i) carbonate dissolution by carbonic acid (-8.25[per mille sign]) > (ii) silicate dissolution by carbonic acid (-17[per mille sign]) [approximate] (iii) carbonate dissolution by sulfuric acid derived from the oxidation of sulfides (coupled sulfide-carbonate weathering) (+0.5[per mille sign]). [delta]34SSO4 is negatively correlated with [delta]13CDIC in the Cordilleran rivers, which further supports the hypothesis that sulfuric acid produced by sulfide oxidation is primarily neutralized by carbonates, and that sulfide-carbonate weathering impacts the [delta]13CDIC of rivers. The negative correlation between [delta]34SSO4 and [delta]13CDIC is not observed in the Ottawa and St. Lawrence River basins. This suggests other factors such as landscape age (governed by tectonic uplift) and bedrock geology are important controls on regional sulfide oxidation rates, and therefore also on the magnitude of sulfide-carbonate weathering--i.e., it is more significant in tectonically active areas. Calculated DIC fluxes due to Ca and Mg silicate weathering by carbonic acid (38.3 x 103 mol C [middle dot] km-2 [middle dot] yr-1) are similar in magnitude to DIC fluxes due to sulfide-carbonate weathering (18.5 x 103 mol C [middle dot] km-2 [middle dot] yr-1). While Ca and Mg silicate weathering facilitates a transfer of atmospheric CO2 to carbonate rocks, sulfide-carbonate weathering can liberate CO2 from carbonate rocks to the atmosphere when sulfide oxidation exceeds sulfide deposition. This implies that in the Canadian Cordillera, sulfide-carbonate weathering can offset up to 48% of the current CO2 drawdown by silicate weathering in the region.

Collaborative information seeking: A field study of a multidisciplinary patient care team

Madhu Reddy — 2008-04-04T12:50:00-00:00

Inf. Process. Manage., Vol. 44, No. 1. (January 2008), pp. 242-255.

Multidisciplinary teams are an essential aspect of modern organizational work. These teams often work in informationrich environments but little is known about their collaborative information seeking (CIS) behavior. We have been studying the CIS behavior of teams in the context of medical care. We conducted an ethnographic ﬁeld study of a multidisciplinary patient care team in an emergency department to identify (a) team information needs and (b) situations that trigger collaborative information seeking activities. We identiﬁed seven categories of information needs as expressed by questions asked by team members. The majority of questions focused on medical information, but there were a larger than expected percentage of questions focusing on organizational information. We also identiﬁed three triggers for CIS activities. These triggers are: (1) lack of expertise, (2) lack of immediately accessible information, and (3) complex information needs. The questions and triggers highlight the importance of face-to-face communication during CIS activities and how CIS activities could lead to interruptive workplaces. We also discuss organizational and technical implications for supporting CIS behavior of teams.

Strong Association of De Novo Copy Number Mutations with Autism.

Jonathan Sebat — 2007-04-19T17:15:36-00:00

Science (15 March 2007)

We tested the hypothesis that de novo copy number variation (CNV) is associated with autism spectrum disorders (ASDs). We performed comparative genomic hybridization (CGH) on the genomic DNA of patients and unaffected subjects to detect copy number variants not present in their respective parents. Candidate genomic regions were validated by higher-resolution CGH, paternity testing, cytogenetics, fluorescence in situ hybridization, and microsatellite genotyping. Confirmed de novo CNVs were significantly associated with autism (P = 0.0005). Such CNVs were identified in 12 out of 118 (10%) of patients with sporadic autism, in 2 out of 77 (2%) of patients with an affected first-degree relative, and in 2 out of 196 (1.0%) of controls. Most de novo CNVs were smaller than microscopic resolution. Affected genomic regions were highly heterogeneous and included mutations of single genes. These findings establish de novo germline mutation as a more significant risk factor for ASD than previously recognized.

The behaviour and ecology of the zebrafish, Danio rerio

Rowena Spence — 2008-02-22T15:24:10-00:00

Biological Reviews, Vol. 83, No. 1. (2008), pp. 13-34.

Abstract The zebrafish Danio rerio, is an important model organism in developmental genetics, neurophysiology and biomedicine, but little is known about its natural ecology and behaviour. It is a small, shoaling cyprinid, native to the flood-plains of the Indian subcontinent, where it is found in shallow, slow-flowing waters. Zebrafish are group spawners and egg scatterers, although females are choosy with respect to sites for oviposition and males defend territories around such sites. Laboratory studies of zebrafish behaviour have encompassed shoaling, foraging, reproduction, sensory perception and learning. These studies are reviewed in relation to the suitability of the zebrafish as a model for studies on cognition and learning, development, behavioural and evolutionary ecology, and behavioural genetics.

'Pod shatter' in Arabidopsis thalianaBrassica napus and B. juncea

J Spence — 2008-03-18T15:18:32-00:00

Journal of Microscopy, Vol. 181, No. 2. (1996), pp. 195-203.

Wild Brassica plants release seeds by a pod shattering mechanism; in related crop plants, such as oil-seed rape, this can result in substantial loss of seed, and hence loss of revenue, and also in the distribution of seeds which can contaminate future crops and the environment. To identify strategies which may be used to reduce shatter, either by conventional breeding programmes or by genetic engineering, we have examined fruit development in oil-seed rape (Brassica napus), and in the related B. juncea and Arabidopsis, using a combination of cytological, cytochemical and molecular techniques. We report here on the patterns of cellular differentiation and tissue development during fruit maturation, and suggest how this results in the shattering phenotype.

How 'special' is the human face? Evidence from an audiovisual temporal order judgment task.

A Vatakis — 2008-02-26T19:58:50-00:00

Neuroreport, Vol. 18, No. 17. (19 November 2007), pp. 1807-1811.

Upright and inverted audiovisual video clips of a monkey producing a 'coo' and a human imitating this vocalization were presented at a range of stimulus onset asynchronies. Participants made temporal order judgments regarding which modality stream appeared to have been presented first. The results showed that inverting the dynamic human visual display led to a significant differences in the point of subjective simultaneity, with the inverted human faces requiring more time to be processed compared with the upright displays. No such inversion effect was found for the monkey visual displays. These results demonstrate that the effect of inversion on the temporal perception of audiovisual speech stimuli are driven by the viewing of a human face rather than by the integration of audiovisual speech.

Dispossessing the Wilderness: Indian Removal and the Making of the National Parks

Mark Spence — 2005-11-14T19:24:48-00:00

(14 December 2000)

National parks like Yellowstone, Yosemite, and Glacier preserve some of this country's most cherished wilderness landscapes. While visions of pristine, uninhabited nature led to the creation of these parks, they also inspired policies of Indian removal. By contrasting the native histories of these places with the links between Indian policy developments and preservationist efforts, this work examines the complex origins of the national parks and the troubling consequences of the American wilderness ideal. The first study to place national park history within the context of the early reservation era, it details the ways that national parks developed into one of the most important arenas of contention between native peoples and non-Indians in the twentieth century.

Psychometric properties of the Spence Children's Anxiety Scale with young adolescents

SH Spence — 2004-12-28T17:08:36-00:00

Journal of Anxiety Disorders, Vol. 17, No. 6. (2003), pp. 605-625.

Acculturation, Drinking, and Alcohol Abuse and Dependence Among Hispanics in the TexasMexico Border

Caetano — 2008-01-31T12:41:12-00:00

Alcoholism Clinical and Experimental Research, Vol. 32, No. 2. (February 2008), pp. 314-321.

Cost Reduction, Competition, and Industry Performance

Michael Spence — 2008-01-30T00:27:59-00:00

Econometrica, Vol. 52, No. 1. (1984), pp. 101-122.

Multisensory Cues Capture Spatial Attention Regardless of Perceptual Load

Valerio Santangelo — 2008-01-26T19:19:12-00:00

Journal of Experimental Psychology: Human Perception and Performance, Vol. 33, No. 6. (December 2007), pp. 1311-1321.

We compared the ability of auditory, visual, and audiovisual (bimodal) exogenous cues to capture visuo-spatial attention under conditions of no load versus high perceptual load. Participants had to discriminate the elevation (up vs. down) of visual targets preceded by either unimodal or bimodal cues under conditions of high perceptual load (in which they had to monitor a rapidly presented central stream of visual letters for occasionally presented target digits) or no perceptual load (in which the central stream was replaced by a fixation point). The results of 3 experiments showed that all 3 cues captured visuo-spatial attention in the no-load condition. By contrast, only the bimodal cues captured visuo-spatial attention in the high-load condition, indicating for the first time that multisensory integration can play a key role in disengaging spatial attention from a concurrent perceptually demanding stimulus.

Information Visualization

Robert Spence — 2005-03-04T08:45:02-00:00

(15 December 2000)

B></I></B></U> This is the first fully integrated book on the emerging area of information visualization, incorporating dynamic examples on an accompanying website to complement the static representations within the book. Its emphasis is on real-world examples and applications of computer-generated/interactive information visualization. Readers will learn how to display information to: pick out key information from large data streams; present ideas clearly and effectively; and increase the usability and efficiency of computer systems. It takes a dynamic approach to the subject using software examples on an associated website. This book is appropriate for readers interested in information visualization, human-computer interaction, business information technology, and computer graphics

Role of renin-angiotensin system blockade in atherosclerotic renal artery stenosis and renovascular hypertension.

DG Hackam — 2008-01-03T09:36:19-00:00

Hypertension, Vol. 50, No. 6. (December 2007), pp. 998-1003.

Vaginal discharge.

D Spence — 2008-01-02T08:37:01-00:00

BMJ, Vol. 335, No. 7630. (1 December 2007), pp. 1147-1151.

Use of Home Videotapes to Confirm Parental Reports of Regression in Autism

Wendy Goldberg — 2007-12-19T21:12:34-00:00

Journal of Autism and Developmental Disorders

Abstract The current study examined consistency between parental reports on early language development and behaviors in non-language domains and observer-coded videotapes of young children with and without autism spectrum disorder (ASD) and autistic regression. Data are reported on 56 children (84% male) with ASD (early onset or autistic regression) and 14 typically developing children (57% male) who had home videotapes. Unique to the current study is the independent identification of loss/no loss for each child by both parental report and observer-coded home videotapes and the examination of agreement between these two methods. Results indicate substantial concordance between parental report and observer codes for onset and loss of expressive language, but minimal concordance for loss in non-language domains, suggesting a need for supplementation of parental reports in these areas.

Evaluating the influence of the `unity assumption' on the temporal perception of realistic audiovisual stimuli

Argiro Vatakis — 2007-12-16T22:59:33-00:00

Acta Psychologica, Vol. 127, No. 1. (January 2008), pp. 12-23.

Vatakis, A. and Spence, C. (in press) [Crossmodal binding: Evaluating the `unity assumption' using audiovisual speech stimuli. Perception & Psychophysics] recently demonstrated that when two briefly presented speech signals (one auditory and the other visual) refer to the same audiovisual speech event, people find it harder to judge their temporal order than when they refer to different speech events. Vatakis and Spence argued that the `unity assumption' facilitated crossmodal binding on the former (matching) trials by means of a process of temporal ventriloquism. In the present study, we investigated whether the `unity assumption' would also affect the binding of non-speech stimuli (video clips of object action or musical notes). The auditory and visual stimuli were presented at a range of stimulus onset asynchronies (SOAs) using the method of constant stimuli. Participants made unspeeded temporal order judgments (TOJs) regarding which modality stream had been presented first. The auditory and visual musical and object action stimuli were either matched (e.g., the sight of a note being played on a piano together with the corresponding sound) or else mismatched (e.g., the sight of a note being played on a piano together with the sound of a guitar string being plucked). However, in contrast to the results of Vatakis and Spence's recent speech study, no significant difference in the accuracy of temporal discrimination performance for the matched versus mismatched video clips was observed. Reasons for this discrepancy are discussed.

Lexical co-occurrence and association strength

Donald Spence — 2007-12-16T16:48:29-00:00

Journal of Psycholinguistic Research, Vol. 19, No. 5. (1990), pp. 317-330.

The 1-million-word Brown corpus was searched for co-occurrences of semantically related pairs of concrete nouns appearing within an arbitrary window of 250 characters. Related pairs of nouns (OCEAN-WATER) co-occur significantly more often than matched, unrelated pairs (OCEAN-HAND), and this difference remained significant within blocks of text up to 1000 characters in length. Frequency of co-occurrence, corrected for chance, is significantly correlated with association strength. Lexical distance between co-occurring members of a given pair is inversely correlated with association strength. Significantly more co-occurrences were found, per unit text, in the fictional sections of the corpus.

May the force be with you

Des Spence — 2007-12-08T07:29:12-00:00

BMJ, Vol. 335, No. 7630. (1 December 2007), 1158.

10.1136/bmj.39412.648576.94