bluuebunny/crossref_metadata_2025 huggingface dataset:
A General Model for the Perception of Space and Motion
Authors: Wade Nicholas J , Swanston Michael T
Published: January 2007

The perception of space and motion involves successive transformations of signals with respect to different reference systems. The visual input is coded in terms of retinal coordinates. The retinocentric values from each eye require to be unified, and to be combined with signals for eye position and movement. This egocentric reference provides a signal for the angular size, motion, or orientation of the stimulus with respect to the observer. The egocentric signals are transformed to a coordinate system that is three-dimensional—the geocentric frame of reference. Further transformations can occur at earlier levels owing to patterncentric interactions within the visual field. When the geocentric signal corresponds to the physical dimensions of space and motion, this is referred to as perceptual constancy.
Visual Inspection of Three-Dimensional Objects by Human Observers
Authors: Niemann Tobias , Lappe Markus , Hoffmann Klaus-Peter
Published: January 2007

Eye movements are an important aid in active visual exploration of the environment and in performing behavioural tasks. Eye movements might also play a role in human perception of three-dimensional (3-D) objects. Eye-movement strategies were investigated when humans inspected and memorised 3-D objects. Subjects were instructed to memorise the 3-D structure of parts of statues of human figures placed on a turntable free to rotate through 360°. Eye movements and turning behaviour were recorded. Different turning and eye-movement strategies could be observed. Subjects showed individual turning behaviours that were reproducible between trials. Turning strategies ranged from focusing on only a limited number of perspective views to almost continuously rotating the object with only short stops. On average twelve–thirteen views were inspected during memorising. Eye movements also revealed individual strategies. Fixation locations within each inspection view ranged from either closely spaced on isolated parts of the object to distributed over the whole view with large saccades in between. Eye movements were often directed to the same details from different perspectives. The differences in turning and viewing strategy also resulted in differences in the ability to recognise parts of the object later on. In general, successful later recognition required that the subject actually fixated the part to be recognised. A strategy of thoroughly inspecting the object with a series of closely spaced fixations from only a limited number of viewpoints led to best recognition rates. This was especially true for two subjects trained in fine arts with prior experiences in modelling. The results support models of viewpoint-dependent object recognition with viewer-centred, two-dimensional representations of 3-D objects.
Patterns That Impair Discrimination of Line Orientation in Human Vision
Authors: Wehrhahn Christian , Li Wu , Westheimer Gerald
Published: January 2007

The threshold for detecting a change in orientation away from the vertical of a briefly presented foveal line target is raised when there are immediately following visual presentations. This masking effect was examined by measuring the capacity of a variety of patterns to act as masks. When patterns were made of exactly the same number of light pixels, masking was least when they formed random dots and progressively became stronger as they formed lines of decreasing curvature from full circles to straight lines. The longer the lines, the stronger the masking. Threshold elevation was highest when the masking pattern was spatially superimposed on the line and was lessened when a large surround area was included, but there was still considerable masking when the interfering patterns were confined to the surround. By placing masks and test lines in different eyes, or by giving them opposite contrast polarity, almost complete interocular and interpolarity transfer was demonstrated. Relating these results to anatomical and electrophysiological findings about neurons in the primary visual cortex leads to the conclusion that the masking effects could have their substrates in interaction between cells in V1.
Horses are Sensitive to Pictorial Depth Cues
Authors: Timney Brian , Keil Kathy
Published: January 2007

In an attempt to demonstrate whether horses could make use of pictorial cues to depth, two were trained initially to make a relative-line-length discrimination between two lines placed one above the other. Psychophysical measurement of their discrimination thresholds showed that from a viewing distance of approximately 160 cm they could reliably distinguish a lower line of 10 cm from an upper one of 14 cm. In the second phase of the experiment, two lines of equal length were superimposed on a photograph of a set of railway tracks with many pictorial cues to depth, or a photograph of a pastoral scene with fewer obvious depth cues. To humans, the railway tracks created a Ponzo illusion, making the upper line appear longer. When the horses were allowed to choose between the photographs, they overwhelmingly chose the display containing the converging railway tracks. Control experiments ruled out alternative explanations, leading to the conclusion that horses are susceptible to a Ponzo illusion created by depth cues in photographs.
Transient—Sustained Input to Directionally Selective Motion Mechanisms
Authors: Bischof Walter F , Seiffert Adriane E , Di Lollo Vincent
Published: January 2007

The characteristics of the sustained input to directionally selective motion sensors were examined in three human psychophysical studies on directional-motion discrimination. Apparent motion was produced by displaying a group of dots in two frames (F1 and F2), where F2 was a translated version of F1. All stimuli included parts that contained both F1 and F2 (combined images) and parts containing only F1 or F2 (single images). All displays began with a single image (F1), continued with the combined image, and ended with F2. Six durations of single and of combined images (10, 20, 40, 80, 160, or 320 ms) were crossed factorially. As the duration of the single image was increased, perception of directional motion first improved, and then declined at longer durations. This outcome contrasted with the monotonic increment obtained in earlier studies under low-luminance conditions. To account for the entire pattern of results, earlier models of the Reichardt motion sensor were modified so as to include a mixed transient – sustained input to one of the filters of the sensor. Predictions from the new model were tested and confirmed in two experiments carried out under both low-luminance and high-luminance viewing conditions.
Distractor Heterogeneity versus Linear Separability in Colour Visual Search
Authors: Bauer Ben , Jolicoeur Pierre , Cowan William B
Published: January 2007

D'Zmura, and Bauer, Jolicoeur, and Cowan demonstrated that a target whose chromaticity was linearly separable from distractor chromaticities was relatively easy to detect in a search display, whereas a target that was not linearly separable from the distractor chromaticities resulted in steep search slopes. This linear separability effect suggests that efficient colour visual search is mediated by a chromatically linear mechanism. Failure of this mechanism leads to search performance strongly influenced by number of search items (set size). In their studies, linear separability was confounded with distractor heterogeneity and thus the results attributed to linear separability were also consistent with the model of visual search proposed by Duncan and Humphreys in which search performance is determined in part by distractor heterogeneity. We contrasted the predictions based on linear separability and on the Duncan and Humphreys model by varying the ratios of the quantities of the two distractors and demonstrated the potent effects of linear separability in a design that deconfounded linear separability and distractor heterogeneity.
The Effect of Attention on Phenomenal Length
Authors: Prinzmetal William , Wilson Anna
Published: January 2007

The effect of attention of the perceived length of briefly presented peripheral lines was investigated. Attention was manipulated by engaging observers in a second concurrent task (letter identification). Observers used the method of adjustment to indicate the length of the stimulus lines. In two experiments it was found that the primary effect of attention was to reduce the variability of line length adjustments. Previously investigators had reported that attention reduces perceived line length. A third experiment suggested that these previously reported results might have been the outcome of a spatial interaction with the cue used to manipulate attention, but not the result of visual attention.
Correcting Some Misperceptions of Time-to-Collision: A Critical Note
Authors: Tresilian James R
Published: January 2007

Stewart et al (1993, Perception22 1227–1244) attempted to demonstrate that the ratio of angular speed to angular acceleration, θ̇/θ̈, of the approaching object is preferred as the source of time-to-collision information to the ratio of visual angle to angular speed, θ/θ̇. It is demonstrated that this is not justified.
Response to the Critical Note “Correcting Some Misperceptions of Time-To-Collision” by James R Tresilian
Authors: Stewart Douglas L , Cudworth Christopher J , Lishman J R
Published: January 2007

In an earlier paper, “Misperception of time-to-collision by drivers in pedestrian accidents”, it was proposed that time-to-collision is derived from the angular speed and angular acceleration of an approaching object, with the use of the algorithm 2θ̇/θ̈, rather than from θ/θ̇. This response to the critical paper by Tresilian is intended to support that conclusion, which was based on four main arguments:

(1) the focus of expansion could not provide a reliable datum for judging θ; (2) the need to judge θ is removed by using 2θ̇/θ̈ instead of θ/θ̇; (3) 2θ̇/θ̈ should provide time-to-collision more rapidly and accurately than θ/θ̇; (4) 2θ̇/θ̈ overcomes the inadequacy of θ/θ̇ with accelerating objects.
Spectral Envelope and Context Effects in the Tritone Paradox
Authors: Repp Bruno H
Published: January 2007

In previous studies of the ‘tritone paradox’ Deutsch has suggested that, when listeners are presented with pairs of octave-complex tones that are equal in average log frequency but differ in chroma by 6 semitones (a tritone), they perceive the direction of the chroma difference according to an individual pitch-class template. However, it has also been found that the perceived direction changes for many listeners when the spectral envelope of the tones is shifted along the frequency axis. Reanalysis of these data indicates a strong tendency to perceive the pitch class corresponding to the frequency on which the spectral envelope is centered as subjectively lowest. In experiment 1 this spectral-envelope effect was replicated with tone pairs presented in isolation, at the rate of one a day, which rules out artifacts of test format. In experiment 2, involving another context-free format, envelope center frequency was varied over a wide range and it was shown that some individuals are totally envelope dependent, whereas others rely more on pitch class, and yet others show mixed patterns. Experiment 3 demonstrated that listeners' judgments of tritone pairs can be swayed easily by preceding context. Finally, experiment 4 showed that strong envelope effects are also obtained with Deutsch's own tritone test (issued on CD). The subjective relative pitch height of octave-complex tones thus depends on several competing factors, only one of which is pitch class.
Motion Transparency in Superimposed Dense Random-Dot Patterns: Psychophysics and Simulation
Authors: Murakami Ikuya
Published: January 2007

To determine the mechanism underlying motion transparency, representative examples of motion transparency are listed and possible mechanisms are suggested. Those are feature tracking, multiple spatial-frequency channels, luminance-based transparency rules, and motion energy. Next, an interesting stimulus for motion transparency is introduced, namely superimposed dense random-dot patterns, which is not explained by feature tracking or multiple spatial-frequency channels. A psychophysical experiment reveals that the occurrence of motion transparency in this stimulus depends on three luminance levels assigned to three possible combinations of component dots: (1) white dots superimposed upon white dots, (2) white dots upon black dots, and (3) black dots upon black dots. However, physical rules of luminance-based transparency fail to explain the results. Finally, a computer simulation reveals that a computational model based on motion energy quantitatively predicts the human psychophysical performance. All the results support the idea that motion-energy detection followed by spatial integration is a likely candidate for the mechanism underlying motion transparency.
Global Orientation Disrupts the Detection of a Similar Local Orientation
Authors: Lauwereyns Johan , d'Ydewalle Géry
Published: January 2007

Two experiments were carried out with organised displays in order to examine the role of similarity between global and local orientation in visual search. In both experiments, distractors were organised to form a diagonal line of plus or minus 45°. In experiment 1, target displays were presented tachistoscopically. Participants searched for a target letter ‘Q’ among distractor letters ‘O’. In experiment 2, participants performed a heterogeneity task with target line segments that could have an orientation of either plus or minus 45°. The target appeared partly or completely inside a distractor circle. In both experiments, the target was more difficult to detect when the critical feature aligned with the slope of the global diagonal than when the feature did not align. Taken together, the two experiments suggested a sequential global-to-local processing in which the orientation of the global figure disrupts the detection of a similar local orientation.
What Represents a Face? A Computational Approach for the Integration of Physiological and Psychological Data
Authors: Valentin Dominique , Abdi Hervé , Edelman Betty
Published: January 2007

Empirical studies of face recognition suggest that faces might be stored in memory by means of a few canonical representations. The nature of these canonical representations is, however, unclear. Although psychological data show a three-quarter-view advantage, physiological studies suggest profile and frontal views are stored in memory. A computational approach to reconcile these findings is proposed. The pattern of results obtained when different views, or combinations of views, are used as the internal representation of a two-stage identification network consisting of an autoassociative memory followed by a radial-basis-function network are compared. Results show that (i) a frontal and a profile view are sufficient to reach the optimal network performance; and (ii) all the different representations produce a three-quarter view advantage, similar to that generally described for human subjects. These results indicate that although three-quarter views yield better recognition than other views, they need not be stored in memory to show this advantage.
Loss of a Forest: Perceptual Fading and Filling-in of Static Texture Patterns
Authors: Gyoba Jiro
Published: January 2007

Fading and filling-in of static texture patterns is demonstrated with the use of a matrix of Chinese characters with vertical or oblique line components. An asymmetric effect is demonstrated by exchanging foreground and background characters.
Steering without Representation with the Use of Active Fixation
Authors: Murray David W , Reid Ian D , Davison Andrew J
Published: January 2007

This paper demonstrates the use of active fixation on both fixed and moving fixation points to guide a robot vehicle by means of a steering rule which, at large distances, sets the steering angle directly proportional to the deviation of gaze direction from translation direction. Steering a motor vehicle around a winding but otherwise uncluttered road has been observed by Land and Lee to involve repeated periods of visual fixation upon the tangent point of the inside of each bend. We suggest that proportional rule devised for steering in the robotic example appears applicable to the observed human performance data, providing an alternative explanation to the quadratic rule proposed by Land and Lee.
Viscosity Discrimination: A Comparison of an Adaptive Two-Alternative Forced-Choice and an Adjustment Procedure
Authors: Jones Lynette , Hunter Ian , Lafontaine Serge
Published: January 2007

Differential thresholds for viscosity were measured in ten subjects with the use of an adaptive two-alternative forced-choice procedure. An electromagnetic linear motor was connected to each wrist and the viscosity of the motors was under computer servo control. For each block of 50 trials the viscosity of one motor was fixed at a reference value which ranged from 4 to 512 N s m−1, and the viscosity of the other motor varied according to the subject's responses. On each trial subjects were required to indicate which motor had the greater viscosity and were given feedback of the correct response. By this procedure the Weber fraction for viscosity was calculated to be 19%, which is lower than the Weber fraction of 34% estimated by using the method of adjustment. The criterion used for determining the threshold differs in the two procedures (71% and 84% correct, respectively), and the results from the two studies were found to be consistent. They suggest that the Weber fraction for viscosity remains remarkably stable despite differences in the methods of measurement.
Perceived Similarity of Shapes is an Asymmetrical Relationship: A Study of Typical Contours
Authors: Deręgowski Jan B , McGeorge Peter
Published: January 2007

Two experiments are reported in which the relationship between perceived similarity amongst simple geometric solids and the set of projections arising from rotation of the typical contour of the solids about a vertical axis in its plane are examined. The results indicate (1) that judgments of similarity are affected by pronouncedness of typical contours, (2) similarity of simple geometrical solids is an asymmetrical attribute, in that where a set of possible projections of model X contains a set of possible projections of model Y, then model Y is judged as more similar to model X than X is to Y. The implications of this asymmetry for perceptual constancy and theories of object recognition are discussed.
Types of Shear Disparity and the Perception of Surface Inclination
Authors: Howard Ian P , Pierce Byron J
Published: January 2007

A study is reported of (i) the perceived inclination of a textured surface in depth about a horizontal axis as a function of disparity magnitude for horizontal-shear disparity, vertical-shear disparity, and rotation disparity; and (ii) interactions between patterns with shear or rotation disparity and superimposed or adjacent patterns or lines with zero disparity. Horizontal-shear disparity produced strong inclination which was enhanced by superimposed or adjacent zero-disparity stimuli. It produced little or no inclination contrast in superimposed or adjacent zero-disparity stimuli. Vertical-shear disparity produced inclination in the opposite direction (induced effect) which was reduced to near zero by a superimposed zero-disparity pattern. Adjacent vertical-shear and zero-disparity patterns appeared inclined at slightly different angles with a wide curved boundary. This suggests that vertical-shear disparities are averaged over a wide area. Rotation disparity produced minimal inclination. A superimposed or adjacent zero-disparity line appeared strongly inclined. A superimposed or adjacent zero-disparity pattern appeared vertical and caused the pattern with rotation disparity to appear inclined. Four mechanisms are proposed to account for the results: depth contrast, depth enhancement, deformation-disparity processing, and disparity transfer arising from cyclovergence.
Presence and Absence of Top and Right Advantage as an Indication of the Attentional Strategies Underlying Object Selection
Authors: Avrahami Judith
Published: January 2007

To explore the conditions in which an object is selected in its entirety and better understand the process underlying such selection, a target, lying on the contour of an outline figure, was judged. Target position on the figure was either known or not known throughout a block of trials, and various properties of the figure itself—continuity, familiarity, and contrast—were manipulated. The pattern of results can best be accounted for by assuming that object selection involves a scan, beginning at the top-right end and terminating only when the bottom-left end is reached. Partial selection could have occurred only for the top and the right positions when the target was known always to be there. As to the manipulated properties, none interacted with knowledge of target position, indicating that they did not affect the process of selection. Most importantly, partial selection was not facilitated even in the discontinuous condition, in which the figure consisted of two separate elements.
Relative Spatial Expansion and Contraction within the Müller-Lyer and Judd Illusions
Authors: Post Robert B , Welch Robert B , Caufield Kristin
Published: January 2007

The shaft portions of Müller-Lyer (M-L) figures, one-ended M-L figures, Judd figures, and their respective control (tails-up) figures were divided by subjects into eight equal-appearing intervals by means of successive bisections. For most of the control stimuli the length of the left half of the shaft tended to be overestimated relative to the length of the right side. For the tails-out version of the M-L figure, there was relative overestimation of segments of the shaft adjacent to the tails, while for the tails-in version there was relative underestimation of these segments. These results indicate that the distortion of perceived length in the M-L illusion is not distributed evenly along the shaft. For the one-ended M-L figures the apparent overestimations and underestimations extended further along the shaft than for the standard figures. For the Judd figure perceived length varied systematically along the length of the shaft from underestimation near the tails-in end of the figure to overestimation near the tails-out end. These results are contradictory to the hypothesis that the M-L illusion results from inappropriate size scaling produced through the operation of size-constancy mechanisms, since this conjecture would predict uniform expansion or contraction. The results are compared with findings that localization responses are accurate for M-L figures but biased for one-ended M-L figures and Judd figures.
Assimilation of Achromatic Color Cannot Explain the Brightness Effects in the Achromatic Neon Effect
Authors: Albert Marc K
Published: January 2007

If the mouths of the pacmen of a Kanizsa square are colored, for example red, then an illusory red transparent square is seen. In many visual theories such ‘neon color spreading’ is explained by assimilation of chromatic and achromatic color. In this paper the achromatic case was investigated. In a two-alternative forced-choice task thirty observers judged the brightness of achromatic neon figures. The results suggest that assimilation of achromatic color inside and/or outside of the illusory figures cannot explain the brightness effects seen in achromatic neon color spreading. Although these displays may produce assimilation, it appears that contrast (perhaps acting nonlocally) is a stronger influence on their perceived brightness.
Selective Attention to Specific Location Cues: The Peak and Center of a Patch are Equally Accessible as Location Cues
Authors: Akutsu Hiromi , Levi Dennis M
Published: January 2007

Asymmetric patterns have several spatially distinct cues for spatial localization. These cues include the peak of the luminance distribution, the centroid of the contrast distribution, zero-crossings in the second derivative of the luminance profile, and the midpoint of the visible area. If these cues are represented as primitives in the visual system, the observer should be able to access them at will. To examine whether observers can selectively attend to particular cues, we measured perceived alignment for an asymmetric pattern with two distinct instructions: “align the peak”, and “align the center”. We found that observers could align the patterns in accord with the instructions with identical precision, suggesting that the peak and the center cues were equally accessible by the observer. We conclude that multiple localization cues are represented in and can be selectively accessed by the visual system.
Approach to an asymptotic state for zero pressure gradient turbulent boundary layers
Authors: Nagib Hassan M , Chauhan Kapil A , Monkewitz Peter A
Published: January 2007

Flat plate turbulent boundary layers under zero pressure gradient at high Reynolds numbers are studied to reveal appropriate scale relations and asymptotic behaviour. Careful examination of the skin-friction coefficient results confirms the necessity for direct and independent measurement of wall shear stress. We find that many of the previously proposed empirical relations accurately describe the local
C
f
behaviour when modified and underpinned by the same experimental data. The variation of the integral parameter,
H
, shows consistent agreement between the experimental data and the relation from classical theory. In accordance with the classical theory, the ratio of
Δ
and
δ
asymptotes to a constant. Then, the usefulness of the ratio of appropriately defined mean and turbulent time-scales to define and diagnose equilibrium flow is established. Next, the description of mean velocity profiles is revisited, and the validity of the logarithmic law is re-established using both the mean velocity profile and its diagnostic function. The wake parameter,
Π
, is shown to reach an asymptotic value at the highest available experimental Reynolds numbers if correct values of logarithmic-law constants and an appropriate skin-friction estimate are used. The paper closes with a discussion of the Reynolds number trends of the outer velocity defect which are important to establish a consistent similarity theory and appropriate scaling.
Cystic lesions of the head and neck: cytohistological correlation in 63 cases
Authors: Firat P. , Ersoz C. , Uguz A. , Önder S.
Published: January 2007

Objective:  To investigate the accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of cystic masses of the head and neck (H&N), excluding thyroid lesions.

Methods:  A total of 198 cases, 63 of whom had consequent surgical specimens, were retrieved from the files of two university hospitals and reviewed.

Results:  FNAC correctly diagnosed 25 of 36 neoplasms with a cystic component. Five Warthin's tumours, two squamous cell carcinomas, two mucoepidermoid carcinomas and two schwannomas yielded non‐representative aspirates. Four of the missed Warthin's tumours and two mucoepidermoid carcinomas which were misdiagnosed as benign cysts were aspirated by their clinician. One branchial cleft cyst was cytologically interpreted as highly suspicious for carcinoma.

Conclusions:  Disparate entities may present with similar cytological findings in the H&N region. A detailed description of differential diagnosis should be given in the cytology report in suspicious cases. Repeated aspirations from different sites of the lesion may reduce the false‐negative rate.
Expression of GM1, a marker of lipid rafts, defines two subsets of human monocytes with differential endocytic capacity and lipopolysaccharide responsiveness
Authors: Moreno‐Altamirano M. Maximina Bertha , Aguilar‐Carmona Israel , Sánchez‐García F. Javier
Published: January 2007

Monocytes constitute 5–10% of total human peripheral blood leucocytes and remain in circulation for several days before replenishing the tissue macrophage populations. Monocytes display heterogeneity in size, granularity and nuclear morphology, and in the expression of cell membrane molecules, such as CD14, CD16, CD32, CD64, major histocompatibility complex class II, CCR2, CCR5, among others. This has led to the suggestion that individual monocyte/macrophage populations have specialized functions within their microenvironments. This study provides evidence for the occurrence of two peripheral blood monocyte subpopulations on the basis of their differential expression of GM1, a sphingolipid found mostly in lipid rafts, a CD14+ GM1low population and a CD14+ GM1high population comprising about 97·5% and 2·5% of total CD14+ cells, respectively. GM1 expression correlates with functional differences in terms of endocytic activity, susceptibility to mycobacterial infection, and response to lipopolysaccharide (LPS) (modulation of Toll‐like receptor‐4 expression). CD14+ GM1low cells proved to be less endocytic and more responsive to LPS, whereas CD14+ GM1high cells are more endocytic and less responsive to LPS. In addition, during monocyte to macrophage differentiation in vitro, the percentage of CD14+ GM1high cells increases from about 2·5% at day 1 to more than 50% at day 7 of culture. These results suggest that GM1low and GM1high monocytes in peripheral blood, represent either different stages of maturation or different subsets with specialized activities. The expression of CD16 on GM1high favours the first possibility and, on the other hand that up‐regulation of GM1 expression and probably lipid rafts function is involved in the monocyte to macrophage differentiation process.
Street heroin induces mitochondrial dysfunction and apoptosis in rat cortical neurons
Authors: Cunha‐Oliveira Teresa , Rego A. Cristina , Garrido Jorge , Borges Fernanda , Macedo Tice , Oliveira Catarina Resende
Published: January 2007

Cortical function has been suggested to be highly compromised by repeated heroin self‐administration. We have previously shown that street heroin induces apoptosis in neuronal‐like PC12 cells. Thus, we analysed the apoptotic pathways involved in street heroin neurotoxicity using primary cultures of rat cortical neurons. Our street heroin sample was shown to be mainly composed by heroin, 6‐monoacetylmorphine and morphine. Exposure of cortical neurons to street heroin induced a slight decrease in metabolic viability, without loss of neuronal integrity. Early activation of caspases involved in the mitochondrial apoptotic pathway was observed, culminating in caspase 3 activation, Poly‐ADP Ribose Polymerase (PARP) cleavage and DNA fragmentation. Apoptotic morphology was completely prevented by the non‐selective caspase inhibitor z‐VAD‐fmk, indicating an important role for caspases in neurodegeneration induced by street heroin. Ionotropic glutamate receptors, opioid receptors and oxidative stress were not involved in caspase 3 activation. Interestingly, street heroin cytotoxicity was shown to be independent of a functional mitochondrial respiratory chain, as determined using NT‐2 rho0 cells. Nonetheless, in street heroin‐treated cortical neurons, cytochrome c was released, accompanied by a decrease in mitochondrial potential and Bcl‐2/Bax. Pure heroin hydrochloride similarly decreased metabolic viability but only slightly activated caspase 3. Altogether, our data suggest an important role for mitochondria in mediating street heroin neurotoxic effects.
Fibrocytes from burn patients regulate the activities of fibroblasts
Authors: Wang Jian Fei , Jiao Haiyan , Stewart Tara L. , Shankowsky Heather A. , Scott Paul G. , Tredget Edward E.
Published: January 2007

Wound healing requires an elaborate interplay between numerous cell types that orchestrate a series of regulated and overlapping events. Fibrocytes are a unique leukocyte subpopulation implicated in this process. One role proposed for these cells in wound healing is to synthesize extracellular matrix. Interestingly, using mass spectrometry to quantify hydroxyproline, we discovered that the capacity of fibrocytes from normal subjects or from burn patients to produce collagen is much less than that of dermal fibroblasts. Therefore, we investigated whether fibrocytes could play an indirect, regulatory, role in the healing of burn wounds by affecting the functions of dermal fibroblasts. Dermal fibroblasts treated with medium conditioned by burn patient fibrocytes, but not by those derived from normal subjects, showed an increase in cell proliferation and migration. Using confocal microscopy, flow cytometry, and immunoblotting, we found the level of α‐smooth muscle actin (α‐SMA) expression to be increased in these treated dermal fibroblasts, which also showed an enhanced ability to contract collagen lattices. To determine whether these effects could be attributed to transforming growth factor β (TGF‐β1) or to connective tissue growth factor (CTGF), we measured total TGF‐β1 levels in the conditioned medium by an enzyme‐linked immunosorbtion assay and assessed levels of CTGF mRNA and protein in fibroblasts and fibrocytes by reverse transcription‐polymerase chain reaction and Western blotting. The results showed significantly higher levels of TGF‐β1 and CTGF produced by burn patient fibrocytes. In addition, the application of a TGF‐β1 neutralizing antibody significantly reduced the effect of burn patient fibrocyte medium on dermal fibroblast proliferation, migration, and collagen lattice contraction. Our results suggest that in healing burn wounds, fibrocytes could regulate the activities of local fibroblasts.
The Use of CVD Diamond Burs for Ultraconservative Cavity Preparations: A Report of Two Cases
Authors: Carvalho Carlos Augusto R. , Fagundes Ticiane C. , Barata Terezinha J. e. , Trava‐airoldi Vladimir Jesus , Navarro Maria Fidela L.
Published: January 2007

During the past decades, scientific developments in cutting instruments have changed the conventional techniques used to remove caries lesions. Ultrasound emerged as an alternative for caries removal since the 1950s. However, the conventional technology for diamond powder aggregation with nickel metallic binders could not withstand ultrasonic power. Around 5 years ago, an alternative approach using chemical vapor deposition (CVD) resulted in synthetic diamond technology. CVD diamond burs are obtained with high adherence of the diamond as a unique stone on the metallic surface with excellent abrading performance. This technology allows for diamond deposition with coalescent granulation in different formats of substrates. When connected to an ultrasonic handpiece, CVD diamond burs become an option for cavity preparation, maximizing preservation of tooth structure. Potential advantages such as reduced noise, minimal damage to the gingival tissue, extended bur durability, improved proximal cavity access, reduced risk of hitting the adjacent tooth resulting from the high inclination angles, and minimal patient’s risk of metal contamination. These innovative instruments also potentially eliminate some problems regarding decreased cutting efficiency of conventional diamond burs.

CLINICAL SIGNIFICANCE

This clinical report presents the benefits of using CVD diamond burs coupled with an ultrasonic handpiece in the treatment of incipient caries. CVD diamond burs coupled with an ultrasonic device offer a promising alternative for removal of carious lesions when ultraconservative cavity preparations are required. Additionally, this system provides a less‐painful technique for caries removal, with minimal noise.
Introduction: Virginia Woolf and The Art of Exploration
Authors: Seshagiri Urmila , Zimring Rishona
Published: January 2007

This paper introduces a Literature Compass cluster of articles which examines the current state of Virgina Woolf Studies and aims to provide a snapshot of the field. These papers grew out of the 15th Annual International Virginia Woolf Conference (College of Lewis and Clark, Portland, OR, June 9–12, 2005).

The full cluster is made up of the following articles:

“Introduction: Virginia Woolf and The Art of Exploration,” Urmila Seshagiri and Rishona Zimring, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00393.x

“Virginia Woolf's Sense of Adventure,” Maria DiBattista, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00394.x

“The Twentieth Part: Virginia Woolf in the British Museum Reading Room,” Benjamin Harvey, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00395.x

“‘Street Haunting’: Phantasmagorias of the Modern Imperial Metropolis,” Sara Gerend, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00396.x

“Hyde Park Gate News,” Gill Lowe, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00397.x

“The Art of ‘Scene‐Making’ in the Charleston Bulletin Supplements,” Claudia Olk, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00398.x

“A Camera of Her Own: Woolf and the Legacy of the Indomitable Mrs. Cameron,” Emily Setina, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00399.x

“Woolfian Resonances,” Anne Fernald, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00400.x

“Early Twentieth‐Century British Women Travellers to Greece: Contextualizing the Example of Virginia Woolf,” Martha Klironomos, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00401.x

“‘Others Wanted to Travel’: Woolf and ‘America Herself’,” Thaine Stearns, Literature Compass 3 (2006), 10.1111/j.1741‐4113.2006.00402.x
Contributions of host and symbiont pigments to the coloration of reef corals
Authors: Oswald Franz , Schmitt Florian , Leutenegger Alexandra , Ivanchenko Sergey , D'Angelo Cecilia , Salih Anya , Maslakova Svetlana , Bulina Maria , Schirmbeck Reinhold , Nienhaus G. U. , Matz Mikhail V. , Wiedenmann Jörg
Published: January 2007

For a variety of coral species, we have studied the molecular origin of their coloration to assess the contributions of host and symbiont pigments. For the corals Catalaphyllia jardinei and an orange‐emitting color morph of Lobophyllia hemprichii, the pigments belong to a particular class of green fluorescent protein‐like proteins that change their color from green to red upon irradiation with ∼400 nm light. The optical absorption and emission properties of these proteins were characterized in detail. Their spectra were found to be similar to those of phycoerythrin from cyanobacterial symbionts. To unambiguously determine the molecular origin of the coloration, we performed immunochemical studies using double diffusion in gel analysis on tissue extracts, including also a third coral species, Montastrea cavernosa, which allowed us to attribute the red fluorescent coloration to green‐to‐red photoconvertible fluorescent proteins. The red fluorescent proteins are localized mainly in the ectodermal tissue and contribute up to 7.0% of the total soluble cellular proteins in these species. Distinct spatial distributions of green and cyan fluorescent proteins were observed for the tissues of M. cavernosa. This observation may suggest that differently colored green fluorescent protein‐like proteins have different, specific functions. In addition to green fluorescent protein‐like proteins, the pigments of zooxanthellae have a strong effect on the visual appearance of the latter species.
RELATIONSHIP BETWEEN SERUM ENDOCRINE FACTORS, HISTOCHEMICAL CHARACTERISTICS OF LONGISSIMUS DORSI MUSCLE AND MEAT QUALITY IN PIGS
Authors: RYU Y.‐C. , CHOI Y.‐M. , KO Y. , KIM B.‐C.
Published: January 2007

The circulating growth factors, interleukin, cortisol and glycolytic enzyme activities were measured at 7 days before slaughter, and the muscle histochemical characteristics were measured using longissimus dorsi muscle at 45 min postmortem. The total fiber number tended to negatively relate to the concentrations of insulin‐like growth factor (IGF) and transforming growth factor‐β (TGF‐β). The percentage of type I muscle fiber was negatively related to serum IGF‐I concentration, and positively related to serum epidermal growth factor and TGF‐β. Circulating growth factors, interleukin and cortisol were poorly correlated with muscle fiber characteristics and meat quality. These results suggest that endocrine factors measured in antemortem serum may not be appropriate parameters for the prediction of muscle fiber characteristics.

PRACTICAL APPLICATIONS

Selection for lean growth appears to have adversely affected various aspects of pork quality. A higher frequency of pale, soft and exudative meat is often associated with aggressive muscling in pigs. Research on the relationships between muscle intrinsic factors and phenotypic expression in skeletal muscle is important for improving our understanding of the variation of meat quality. This research suggests that endocrine factors measured at 7 days before slaughter may not be appropriate parameters for the prediction of muscle histologic characteristics.
The specificity of motor neurone regeneration (preferential reinnervation)
Authors: Madison R. D. , Robinson G. A. , Chadaram S. R.
Published: January 2007

The major determinant of functional recovery after lesions in the peripheral nervous system is the accurate regeneration of axons to their original target end‐organs. Unfortunately, regenerating motor axons are often misrouted to sensory target end‐organs, and sensory axons formerly innervating skin are often misrouted to muscle. As such regeneration is robust, but often inaccurate, a better understanding of how regenerating axons reinnervate terminal pathways would be of fundamental interest to basic and clinical neuroscience. This review will consider the underlying cellular and molecular mechanisms that influence the accuracy of peripheral nerve regeneration, within the context of ‘preferential motor reinnervation’ (PMR). Much previous work with PMR has utilized the rodent femoral nerve and has shown that regenerating motor axons preferentially, albeit incompletely, reinnervate a distal terminal nerve branch to muscle (quadriceps) vs. skin (saphenous). One interpretation of this body of work has been that Schwann cell tubes have a specific identity that can be recognized by regenerating motor axons and that influences their subsequent behaviour. We disagree with that interpretation, and suggest motor and cutaneous pathways are not inherently different in terms of their ability to support regeneration of motor axons. In fact, recent experiments indicate under certain conditions motor axons will preferentially reinnervate the inappropriate terminal cutaneous pathway instead of the appropriate pathway to muscle. We suggest that it is the relative level of trophic support provided by each nerve branch that determines whether motor axons will remain in that particular branch. Within the context of the femoral nerve model, our results suggest a hierarchy of trophic support for regenerating motor axons with muscle contact being the highest, followed by the length of the terminal nerve branch and/or contact with skin.
Harold Washington and Chicago's Schools Between Civil Rights and the Decline of the New Deal Consensus, 1955–1987
Authors: Carl Jim
Published: January 2007

An early break in Harold Washington's political career came via a 1955 speech he delivered on equality of educational opportunity. Leaders of Chicago's Roosevelt University invited the popular alumnus (Washington was the first African-American class president) to speak at the tenth anniversary of the school's founding. The young Assistant State's Attorney shared the platform with such notables as former First Lady Eleanor Roosevelt, Supreme Court Chief Justice Earl Warren, and newly elected Mayor Richard J. Daley. In his speech, Washington remembered the university as “an experience in democratic living.” He viewed equal educational opportunity as the school's “cornerstone” because its admissions policy relied on objective examinations. At Roosevelt, Washington found “at all levels… people reaching out to fill whatever gaps [less privileged students] may have had in their backgrounds, which might retard them in their efforts… to be more useful citizens in our greater democracy.” Daley loved the crowd-pleasing speech and began grooming Washington to become the next Cook County prosecutor. Washington's career path, however, led elsewhere.
A Progressive Legacy Squandered: TheCardinal PrinciplesReport Reconsidered
Authors: Wraga William G.
Published: January 2007

In 1955, Lawrence Cremin wrote of theCardinal Principlesreport, “Indeed, it does not seem amiss to argue that most of the important and influential movements in the field since 1918 have simply been footnotes to the classic itself.” During the years between the publication of theCardinal Principlesreport and Cremin's remark, most of the major proposals for secondary education in the United States endorsed and elaborated the principles and practices outlined by the Commission on the Reorganization of Secondary Education (CRSE); many of these reports explicitly cited the 1918 document. Over the decade following Cremin's remark, additional reports continued this trend. During the 1950s, however, the weight of opinion about theCardinal Principlesreport began to shift seismically.
“One's Total World View Comes Into Play”: America's Culture War Over Alcohol Education, 1945-1964
Authors: Zimmerman Jonathan
Published: January 2007

In 1948, fundamentalist theologian Edward John Carnell launched a spirited attack upon the “disease concept” of alcoholism. The Bible stated in no uncertain terms that drunkenness was a sin, Carnell wrote. By deeming alcoholism a sickness, clergymen and educators threatened to erode the “sense of guilt” that had once surrounded it. “The drinker takes the first glass as a free agent,” Carnell intoned. “He knows in advance the risks of his act, yet he proceeds…. As a moral, rational being, then, the drunkard is guilty and stands under God's severe wrath.” Yet in public schools and even in churches, Carnell complained, too many Americans learned to regard alcoholism as a medical affliction rather than as an ethical lapse. “The crux of the problem is whether man is made in the image of God, and thus is a responsible moral being, or whether he is just a product of naturalistic forces and is responsible to none,” Carnell concluded. “In judging drunkards, then, one's total world view comes into play.”
Teaching Brown: Reflections on Pedagogical Challenges and Opportunities: Introduction
Authors: Dougherty Jack
Published: January 2007

These first-person reflective essays were written from our perspectives as educators who find it immensely rewarding, yet incredibly challenging, to teach about Brown vs Board of Education. Rarely do we address an issue in our classroom that is wrapped up in so many layers of racial meaning, people's lived experiences, ongoing policy debates, and historical mythology. Teaching Brown forces many of us to confront a number of dilemmas that have no easy answers:

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How do we “keep the struggle alive” in our students' hearts and minds while simultaneously teaching them to think like historians, who do not uncritically accept simplistic or celebratory accounts of the civil rights movement?

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How do we bridge the gap between two diverging bodies of historical scholarship: one that praises desegregation activists who courageously challenged White supremacy and another that celebrates the good qualities of Black segregated schools?

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How can we help our students see connections between historical struggles and contemporary debates over race, education, and power without slipping into presentism, the unfortunate tendency to perceive the past solely through present-day lenses?

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Or how do we connect any of this academic literature to everyday people's lived experiences in the communities around us, whether we teach in the South, the North, or the West?