bluuebunny/crossref_metadata_2025 huggingface dataset:
Why Goethe Rejected Newton's Theory of Light
Authors: Treisman Michel
Published: January 2007

Observations that he himself had made persuaded Goethe to reject Newton's theory of light and to put forward an alternative theory of the colour phenomena seen with a prism. Duck has argued that Goethe's attack on Newton's theory rested on valid experimental observations that appeared to present a difficulty for Newton's theory but to support his own views on colour. Duck has also proposed that these observations may be accounted for as an instance of the Bezold–Brücke phenomenon. It is argued here that this explanation is invalid and that two other features of colour processing can explain Goethe's observations.
Binocular Invariants in Interceptive Tasks: A Directed Perception Approach
Authors: Laurent Michel , Montagne Gilfes , Durey Alain
Published: January 2007

While the perceptual substratum of interceptive tasks has been largely investigated, no studies report unequivocal evidence for the use of a specific source of information. This result can be interpreted differently according to the perceptual theory considered. In the framework of directed perception this result would illustrate the flexibility of our perceptual system performing the same task in different ways under different circumstances. This paper is designed to formalise, for each category of invariant considered (ie temporal, spatial, and spatiotemporal), a binocular invariant leading to specification of the same physical quantity as a monocular invariant identified in the literature. This formalisation illustrates a redundancy of monocular and binocular invariants that is particularly appealing from the viewpoint of directed perception.
Perceived Angular and Linear Size: The Role of Binocular Disparity and Visual Surround
Authors: Kaneko Hirohiko , Uchikawa Keiji
Published: January 2007

An experiment was conducted to investigate the effects of perspective cue and binocular disparity on perceived angular and linear size. Following the ‘angular’ and ‘linear’ instructions, subjects matched the size of two squares, for which the binocular disparity between the centers of the squares and the configuration of the stimulus surrounding the squares were manipulated. Results showed that angular-size matches depended on the retinal-image size and the binocular disparity, and not on the visual-surround stimulus. Linear-size matches, on the other hand, depended on the visual-surround stimulus as well as on the image size and the binocular disparity. The visual-surround stimulus also affects the perceived depth between the test squares. These findings indicate that perceived angular and linear size depend on different processes that use different cues, and suggest that there is a causal relationship between perceived depth and perceived linear size.
The Speed of Visual Search in the Absence of Sensory Effects
Authors: Saarinen Jukka
Published: January 2007

The purpose of this study was to investigate the efficiency or speed of the frequently used L versus T visual search when sensory effects were controlled, ie ‘set size’ was not defined as the number of distractor patterns, but the number of distractors in the display was kept constant and the number of possible target positions varied. A search display consisted of an L-target among T-distractors, and the observer's task was to report the presence or absence of the target (experiment 1) or to identify it (whether the L-target was left-facing or right-facing; experiment 2). The observer was instructed prior to each stimulus block, about the display locations in which the target could appear. In both experiments, search time increased significantly with an increasing number of possible target locations, thus indicating that L versus T search is not ‘serial’ owing to sensory effects. Because, in the first two experiments, a search display was visible until the observer gave a response, ‘serial’ search might have resulted just from eye movements. Therefore, a control experiment was run in which display duration was limited to 150 ms. The results of this experiment showed that, even when eye movements were prevented, the search still occurred ‘serially’, ie response time increased as a function of the number of possible target positions.
Moving Cast Shadows Induce Apparent Motion in Depth
Authors: Kersten Daniel , Mamassian Pascal , Knill David C
Published: January 2007

Phenomenally strong visual illusions are described in which the motion of an object‘s cast shadow determines the perceived 3-D trajectory of the object. Simply adjusting the motion of a shadow is sufficient to induce dramatically different apparent trajectories of the object casting the shadow. Psychophysical results obtained with the use of 3-D graphics are reported which show that: (i) the information provided by the motion of an object's shadow overrides other strong sources of information and perceptual biases, such as the assumption of constant object size and a general viewpoint; (ii) the natural constraint of shadow darkness plays a role in the interpretation of a moving image patch as a shadow, but under some conditions even unnatural light shadows can induce apparent motion in depth of an object; (iii) when shadow motion is caused by a moving light source, the visual system incorrectly interprets the shadow motion as consistent with a moving object, rather than a moving light source. The results support the hypothesis that the human visual system incorporates a stationary light-source constraint in the perceptual processing of spatial layout of scenes.
A Theory of Illusory Lightness and Transparency in Monocular and Binocular Images: The Role of Contour Junctions
Authors: Anderson Barton L
Published: January 2007

A theory of illusory transparency and lightness is described for monocular and binocular images containing X-, T- and I-contour junctions. This theory asserts that the geometric and luminance relationships of contour junctions induce illusory transparency and lightness percepts by causing a phenomenal scission of a homogenous luminance into multiple contributions. Specifically, it is argued that a discontinuous change in contrast along aligned contours that preserve contrast polarity induces a scission of the lower contrast region into a near-transparent surface or an illumination change, and a more distant surface that continues behind this near layer. This scission is assumed to cause changes in perceived lightness and/or surface opacity. Discontinuous changes in contrast along contours also are assumed to induce end-cut illusory contours that run roughly perpendicular to the inducing orientation of the contour, both monocularly and binocularly. Binocular illusory contours are shown to be caused by the presence of unmatchable contour terminators. It is argued that the presented theory can provide a unified account of a variety of monocular and binocular illusions that induce uniform transformations in perceived lightness, including neon-color spreading, the Munker – White illusion, Benary's illusion, and illusory monocular and binocular transparency.
Brightness with and without Perceived Transparency: When Does it Make a Difference?
Authors: Kingdom Frederick A A , Blakeslee Barbara , McCourt Mark E
Published: January 2007

Subjects matched the brightness of test patches whose inner (adjacent) surrounds appeared either as transparent overlays on a wider background that included the test patch or as regions differing in reflectance from the test patch and the outer surround. In the above configurations the luminance and spatial extent of the inner surround was identical, thus controlling for the effects of surround luminance. Configuration condition had a significant effect on test-patch brightness. In general, test-patch brightness was significantly elevated under conditions favouring the interpretation of the stimulus as including a transparent overlay. The largest effect occurred for the configuration in which the perception of transparency was supported by stereo depth cues. The brightness effect was mediated by the virtual transmittance of the transparent overlay, increasing in magnitude with decreasing transmittance. Further, the effect of transparency on brightness was greatest for test-patch luminances near to those of their immediate surrounds.
The Classification of Facial Expressions of Emotion: A Multidimensional-Scaling Approach
Authors: Katsikitis Mary
Published: January 2007

Photographs (study 1) or line-drawing representations (study 2) of posed facial expressions and a list of emotion words (happiness, surprise, fear, disgust, anger, sadness, neutral) were presented to two groups of observers who were asked to match the photographs or line drawings, respectively, with the emotion categories provided. A multidimensional-scaling procedure was applied to the judgment data. Two dimensions were revealed; pleasantness – unpleasantness and upper-face – lower-face dominance. Furthermore, the similarity shown by the two-dimensional structures derived first from the judgments of photographs and second from the line drawings suggests that line drawings are a viable alternative to photographs in facial-expression research.
Reversed Visual Motion and Self-Sustaining Eye Oscillations
Authors: Spillmann Lothar , Anstis Stuart , Kurtenbach Anne , Howard Ian
Published: January 2007

A random-dot field undergoing counterphase flicker paradoxically appears to move in the same direction as head and eye movements, ie opposite to the optic-flow field. The effect is robust and occurs over a wide range of flicker rates and pixel sizes. The phenomenon can be explained by reversed phi motion caused by apparent pixel movement between successive retinal images. The reversed motion provides a positive feedback control of the display, whereas under normal conditions retinal signals provide a negative feedback. This altered polarity invokes self-sustaining eye movements akin to involuntary optokinetic nystagmus.
The Combination of Filters in Early Spatial Vision: A Retrospective Analysis of the Mirage Model
Authors: Morgan Michael J , Watt Roger J
Published: January 2007

Since the discovery of spatial-frequency-tuned channels in the visual system, most theories attempting to account for pattern encoding have assumed that the filters can be independently accessed and flexibly combined. We review here an alternative model, ‘MIRAGE’, in which the filters are inflexibly combined before pattern analysis. In the MIRAGE model the half-wave rectified outputs of all spatial-frequency channels are combined before locating spatial zero-bounded regions in the neural image, which serve as the spatial primitives for pattern analysis. We describe the evidence that led to this model, and review recent evidence on the rules of filter combination.
Color from Motion: Separate Contributions of Chromaticity and Luminance
Authors: Miyahara Eriko , Cicerone Carol M
Published: January 2007

‘Color from motion’ describes the perception of a spread of subjective color over achromatic regions seen as moving. The effect is produced with a stimulus display consisting of colored dots, randomly placed upon a white field, with dots in the test region differing in both chromaticity and luminance from those in the surround. Evidence is presented suggesting that color from motion may be regulated by mechanisms different from those for contour formation and color contrast. (1) Results based on ratings show that, in the absence of luminance differences between the dots in the test and those in the surround regions, chromaticity differences alone are sufficient to produce color spread from motion. As the equiluminance point is approached, subjective color spread is seen despite a reduction in the strength of the subjective contour. Thus, contour formation is not likely to be a prerequisite for color from motion. (2) Color matches show that the hue and saturation of the subjective color spread are determined largely by the chromaticity and the luminance of the dots in the test region, not by those of the dots in the surround for the values explored. This suggests that color from motion may arise in sites distinct from those responsible for the regulation of color contrast.
Interpolation Processes in the Perception of Real and Illusory Contours
Authors: Gegenfurtner Karl R , Brown Joel E , Rieger Jochem
Published: January 2007

The spatial and temporal characteristics of mechanisms that bridge gaps between line segments were determined. The presentation time that was necessary for localisation and identification of a triangular shape made up of pacmen, pacmen with lines, lines, line segments (corners), or pacmen with circles (amodal completion) was measured. The triangle was embedded in a field of distractors made up of the same components but at random orientations. Subjects had to indicate whether the triangle was on the left or on the right of the display (localisation) and whether it was pointing upward or downward (identification). Poststimulus masks consisted of pinwheels for the pacmen stimuli or wheels defined by lines. Stimuli were presented on a grey background and defined by luminance or isoluminant contrast. Thresholds were fastest when the triangle was defined by real contours, as for the pacmen with lines (105 ms) and the lines only (92 ms), slightly slower for corners (118 ms) and pacmen (136 ms), and much slower for the amodally completed pacmen (285 ms). For all inducer types localisation was about 20 ms faster than identification. In a second experiment the relative length of the gap between inducers was varied. Thresholds increased as a function of gap length, indicating that the gaps between the inducers need to be interpolated. There was no significant difference in the speed of this interpolation process between the pacman stimuli and the line-segment stimuli. About 40 ms were required to interpolate 1 deg of visual angle, corresponding to about one third of the distance between inducers. In a third experiment, it was found that processing of isoluminant stimuli was as fast as for low-contrast luminance stimuli, when targets were defined by real contours (lines), but much slower for illusory contours (pacmen). The conclusion is that the time necessary to interpolate a contour depends greatly on the spatial configuration of the stimulus. Since interpolation is faster for the line-segment stimuli, which do not elicit the percept of an illusory contour, the interpolation process seems to be independent of the formation of illusory contours.
Frame-of-Reference and Hierarchical-Organisation Effects in the Rod-and-Frame Illusion
Authors: Zoccolotti Pierluigi , Antonucci Gabriella , Daini Roberta , Martelli Maria Luisa , Spinelli Donatella
Published: January 2007

Two hypotheses proposed as alternatives by Rock—frame of reference and hierarchical organisation of perception—were tested in a series of experiments with the use of the rod-and-frame illusion. This illusion produces errors in the apparent vertical due to the presence of a tilted frame surrounding the test rod. The apparent vertical is shifted in the direction of the frame tilt. When an upright square was added inside the tilted frame, rod-setting errors varied according to the visual characteristics of the display. In the case of a large display presented in the dark (experiment 1), there continued to be large errors in the direction of the outer-square tilt. This finding supports the frame-of-reference hypothesis, which proposes that the orientation of all objects in the visual field is dominated by the most peripheral reference. In the case of a small display presented in a lit environment (experiments 2 and 3), the direction of errors was the opposite. This latter finding was taken to indicate that the rod was set with reference to the perceived tilt of the inner upright square. Thus, according to a hierarchical-organisation hypothesis, the orientation of an object in the visual field is influenced by objects in the immediate surroundings not by outermost reference.

Overall, the results confirm the presence of two qualitatively different classes of orientational phenomena: one is concerned with the definition of egocentric coordinates and one with an object-centred visual representation.
Motion Parallax: Effects of Blur, Contrast, and Field Size in Normal and Low Vision
Authors: Jobling Jeremy T , Mansfield J Stephen , Legge Gordon E , Menge Mark R
Published: January 2007

Can people with different forms of low vision use motion parallax to improve depth judgments? We used a staircase method to compare depth thresholds using motion parallax and static viewing. We tested eighteen normal-vision subjects with a range of simulated deficits in acuity, contrast sensitivity, and simulated peripheral-field loss, and ten low-vision subjects with a wide range of acuity, contrast sensitivity, and field loss. Subjects viewed three vertical cylinders monocularly and indicated which one was at a different depth from the other two. For motion-parallax trials, observers moved their heads (in a viewing assembly on rollers) from side to side over a range of 6 – 12 cm. For static trials, the viewing assembly was fixed in place. Normal-vision subjects' depth thresholds with motion parallax were significantly smaller than those with static viewing by an average factor of 1.95 ( p < 0.05) across all levels of acuity and contrast. For low-vision observers, the depth thresholds exhibited large individual differences; however, the motion-parallax thresholds were smaller than the static thresholds by an average factor of 2.05 (p < 0.01). These findings indicate that motion parallax can provide useful depth information for people with low vision.
Perception of Biological Motion
Authors: Ahlström Vicki , Blake Randolph , Ahlström Ulf
Published: January 2007

Boundary conditions for perception of biological motion were explored with the use of computer-generated point-light animation sequences. Perception of this unique form of structure from motion is immune to variations in dot contrast polarity, dot disparity, and spatial-frequency filtering. Biological motion is perceived in texture-defined animation sequences that presumably stimulate only second-order motion pathways, and it is undisturbed by dichoptic presentation of portions of the animation tokens separately to the two eyes.
Stimulus Context and View Dependence in Object Recognition
Authors: Newell Fiona N
Published: January 2007

The effect of stimulus factors such as interobject similarity and stimulus density on the recognition of objects across changes in view was investigated in five experiments. The recognition of objects across views was found to depend on the degree of interobject similarity and on stimulus density: recognition was view dependent when both interobject similarity and stimulus density were high, irrespective of the familiarity of the target object. However, when stimulus density or interobject similarity was low recognition was invariant to viewpoint. It was found that recognition was accomplished through view-dependent procedures when discriminability between objects was low.

The findings are discussed in terms of an exemplar-based model in which the dimensions used for discriminating between objects are optimised to maximise the differences between the objects. This optimisation process is characterised as a perceptual ‘ruler’ which measures interobject similarity by stretching across objects in representational space. It is proposed that the ‘ruler’ optimises the feature differences between objects in such a way that recognition is view invariant but that such a process incurs a cost in discriminating between small feature differences, which results in view-dependent recognition performance.
Decrement of the Brentano Müller-Lyer Illusion as a Function of Inspection Time
Authors: Predebon John
Published: January 2007

Two experiments are reported in which the decline or decrement in the magnitude of the Brentano Müller-Lyer illusion was measured. Observers made a pre-test judgment and, after a variable intervening time period, a post-test judgment of illusion magnitude. In experiment 1, the intervening time periods were 1, 2, and 3 min during which time the independent groups of observers allocated to each of the three time periods either systematically scanned the Brentano figure (inspection conditions) or waited until the intervening period had elapsed (no-inspection conditions). Experiment 2, which included an additional 5 min intervening time period, evaluated a response-bias explanation for the results of the inspection conditions of experiment 1. Taken together, the findings of the two experiments indicate that sheer inspection of the Brentano figure produces illusion decrement. However, illusion decrement was independent of the duration of the inspection period, with equivalent amounts of decrement occurring across the range of viewing times examined in the two experiments. The pattern of these results suggests that theories of Müller-Lyer decrement must incorporate a factor attributable to, or correlated with, inspection time, whose effect in reducing illusion magnitude is confined mainly to the first 1 or 2 min of active visual inspection of the Brentano illusion figure.
The Luminance Conditions of Fuchs's Transparency in Two-Dimensional Patterns
Authors: Masin Sergio Cesare
Published: January 2007

Fuchs's transparency occurs when the contour of a transparent surface encloses the contour of another surface located on an underlying homogeneous background. The luminance conditions of Fuchs's transparency have not yet been determined. Six experiments were designed to study this problem with achromatic two-dimensional patterns. An ellipse enclosing a coplanar square was briefly presented. It simulated the cast of an elliptical spotlight or shadow on the square. The duration of the ellipse, the luminance of the square before the ellipse appeared, and the luminance of two squares outside the ellipse did not substantially affect the probability of perceiving the ellipse as transparent. However, this probability varied largely with the single values of the stimulus luminance differences and with the order relations of the stimulus luminances. It is concluded that this local and global luminance information conditioned the occurrence of Fuchs's transparency in two-dimensional patterns.
Are There Qualitative Differences between Face Processing in Photographic Positive and Negative?
Authors: Liu Chang Hong , Chaudhuri Avi
Published: January 2007

The question whether face recognition in photographic negative relies more on external features and pictorial cues than in photographic positive was studied in five experiments. Recognition of whole faces as well as both external and internal features of the faces was compared in experiments 1 and 2. The conditions in which views of faces between learning and test were either identical (hence providing maximum pictorial cues) or different (hence reducing such cues) were compared in experiments 3, 4, and 5. The results showed that recognition of internal features in two-tone and multi-tone images suffered more from use of photographic negatives than recognition of external features. Testing with both multi-tone and two-tone images revealed that the deficit caused by view changes between learning and test was no more severe with negatives than with positives. Finally, removing external features made recognition of different views equally more difficult for positives and negatives. Overall, these results point to a qualitative rather than quantitative difference between processing face images in photographic positive and negative.
Illusory Three-Dimensional Rotation of Horizontal Lines: A New Motion-Depth Illusion
Authors: Ito Hiroyuki , Kawabata Eriko
Published: January 2007

A new motion – depth illusion is reported. When a curved aperture translates vertically and stationary horizontal lines can be seen through it, the line lengths on the retina change continuously because of the occlusion. Instead of seeing the aperture translate, subjects sometimes see the lines rotate in depth around a vertical axis. This is a rare kind of illusion: an ambiguous motion which can be seen as either stationary in two dimensions or rotating in three dimensions. Three-dimensional rotation was more often observed when the luminance difference between the horizontal lines and the background was larger than that between the aperture and the background. This illusion demonstrates that motion detection and the structure-from-motion process correlate with figure – ground segregation, depth stratification, and figural-completion processes based on luminance contrast.
Surface Separation Decreases Stereoscopic Slant but a Monocular Aperture Increases it
Authors: Gillam Barbara J , Blackburn Shane G
Published: January 2007

When an isolated surface is stereoscopically slanted around its vertical axis, perceived slant is attenuated relative to prediction, whereas when a frontal-plane surface is placed above or below the slanted surface, slant is close to the predicted magnitude. Gillam et al (1988 Journal of Experimental Psychology: Human Perception and Performance 14 163 – 175) have argued that this slant enhancement is due to the introduction of a gradient of relative disparities across the abutment of the two surfaces which is a more effective stimulus for slant than is the gradient of absolute disparities present when the slanted surface is presented alone. To test this claim we varied the separation between the two surfaces, along either the vertical or depth axis. Since these manipulations have been reported to reduce the depth response to individual relative disparities, they should similarly affect any slant response based on a gradient of relative disparities. As predicted, increasing the separation, vertically or in depth, systematically reduced both the perceived slant of the stereoscopically slanted surface and also the stereo contrast slant induced in the frontal-plane surface. These results are not predicted by alternative accounts of slant enhancement (disparity-gradient contrast, normalisation, frame of reference). We also demonstrated that sidebands of monocular texture, when added to equate the half-image widths of the slanted surface, increased the perceived slant of this surface (particularly when presented alone) and reduced the contrast slant. Monocular texture, by signalling occlusion, appeared to provide absolute slant information which determined how the total relative slant perceived between the surfaces was allocated to each.
Evaluation of a soil moisture sensor to reduce water and nutrient leaching in turfgrass (Cynodon dactylon cv. Wintergreen)
Authors: Pathan S. M. , Barton L. , Colmer T. D.
Published: January 2007

This study evaluated water application rates, leaching and quality of couch grass (Cynodon dactylon cv. Wintergreen) under a soil moisture sensor-controlled irrigation system, compared with plots under conventional irrigation scheduling as recommended for domestic lawns in Perth, Western Australia by the State’s water supplier. The cumulative volume of water applied during summer to the field plots of turfgrass with the sensor-controlled system was 25% less than that applied to plots with conventional irrigation scheduling. During 154 days over summer and autumn, about 4% of the applied water drained from lysimeters in sensor-controlled plots, and about 16% drained from lysimeters in plots with conventional irrigation scheduling. Even though losses of mineral nitrogen via leaching were extremely small (representing only 1.1% of the total nitrogen applied to conventionally irrigated plots), losses were significantly lower in the sensor-controlled plots. Total clippings produced were 18% lower in sensor-controlled plots. Turfgrass colour in sensor-controlled plots was reduced during summer, but colour remained acceptable under both treatments. The soil moisture sensor-controlled irrigation system enabled automatic implementation of irrigation events to match turfgrass water requirements.
Transformation of cone precursors to functional rod photoreceptors by bZIP transcription factor NRL
Authors: Oh Edwin C. T. , Khan Naheed , Novelli Elena , Khanna Hemant , Strettoi Enrica , Swaroop Anand
Published: January 2007

Networks of transcriptional regulatory proteins dictate specification of neural lineages from multipotent retinal progenitors. Rod photoreceptor differentiation requires the basic motif–leucine zipper (bZIP) transcription factor NRL, because loss of
Nrl
in mice (
Nrl
−/−
) results in complete transformation of rods to functional cones. To examine the role of NRL in cell fate determination, we generated transgenic mice that express
Nrl
under the control of
Crx
promoter in postmitotic photoreceptor precursors of WT and
Nrl
−/−
retina. We show that NRL expression, in both genetic backgrounds, leads to a functional retina with only rod photoreceptors. The absence of cones does not alter retinal lamination, although cone synaptic circuitry is now recruited by rods. Ectopic expression of NRL in developing cones can also induce rod-like characteristics and partially suppress cone-specific gene expression. We show that NRL is associated with specific promoter sequences in
Thrb
(encoding TRβ2 transcription factor required for M-cone differentiation) and
S-opsin
and may, therefore, directly participate in transcriptional suppression of cone development. Our studies establish that NRL is not only essential but is sufficient for rod differentiation and that postmitotic photoreceptor precursors are competent to make binary decisions during early retinogenesis.
MicroRNA-155 is induced during the macrophage inflammatory response
Authors: O'Connell Ryan M. , Taganov Konstantin D. , Boldin Mark P. , Cheng Genhong , Baltimore David
Published: January 2007

The mammalian inflammatory response to infection involves the induction of several hundred genes, a process that must be carefully regulated to achieve pathogen clearance and prevent the consequences of unregulated expression, such as cancer. Recently, microRNAs (miRNAs) have emerged as a class of gene expression regulators that has also been linked to cancer. However, the relationship between inflammation, innate immunity, and miRNA expression is just beginning to be explored. In the present study, we use microarray technology to identify miRNAs induced in primary murine macrophages after exposure to polyriboinosinic:polyribocytidylic acid or the cytokine IFN-β. miR-155 was the only miRNA of those tested that was substantially up-regulated by both stimuli. It also was induced by several Toll-like receptor ligands through myeloid differentiation factor 88- or TRIF-dependent pathways, whereas up-regulation by IFNs was shown to involve TNF-α autocrine signaling. Pharmacological inhibition of the kinase JNK blocked induction of miR-155 in response to either polyriboinosinic:polyribocytidylic acid or TNF-α, suggesting that miR-155-inducing signals use the JNK pathway. Together, these findings characterize miR-155 as a common target of a broad range of inflammatory mediators. Importantly, because miR-155 is known to function as an oncogene, these observations identify a potential link between inflammation and cancer.
Mélange de Configurations dans les Spectres du Titane et du Vanadium Plusieurs Fois Ionisés
Authors: J -F Wyart
Published: January 2007

A theoretical investigation of some excited configurations of Ti III, V III and V IV has led to confirmation of the experimental labelling of energy levels and to the displaying of configuration interaction. Energies and eigen-functions are obtained by taking into account both interaction with close configurations and distant interaction effects, and fit satisfactorily with experimental data.
Stark Effect Investigation of D States in85Rb and133Cs Using Level Crossing Spectroscopy with a CW Dye Laser
Authors: W Hogervorst  , S Svanberg
Published: January 2007

Stark effect investigations in the 6, 7 and 82D3/2,5/2levels of85Rb and the 8, 9 and 102D3/2,5/2levels of133Cs were performed with the level crossing technique. The levels were populated in a two-step excitation process, involving a CW tunable dye laser. The tensor polarizability of all states was measured and a good agreement with theoretical values, obtained with the Coulomb approximation, is found. Furthermore, the signs of the dipole interaction constants, determined to absolute value in earlier experiments, could be inferred. The sign was found to be positive for the2D3/2states and negative for the2D5/2states, indicating strong polarization effects in the magnetic hyperfine interaction.
Lifetimes of the 11/2- Isomers in Odd-proton N=82 Nuclei
Authors: W D Fromm  , L Funke  , K D Schilling
Published: January 2007

The lifetimes of the 11/2- states in 145
63Eu82, 143
61Pm82, 141
59Pr82 and 139
57La52 and an additional lifetime in 143Pm were determined. The results are relevant for a discussion of the amount of mixing of one- and three-quasiparticle states.
Design of an Apparatus for High Resolution Measurements of Atomic and Molecular Lifetimes by the High Frequency Deflection Technique
Authors: P Erman  , J Brzozowski
Published: January 2007

The High Frequency Deflection technique introduced at this laboratory a couple of years ago has proved to be a very versatile general method for measuring optical lifetimes. Thus lifetime measurements have been performed in a large number of atoms, ions, molecules and ion-molecules with much greater efficiency than other methods permit and at 20-50 times higher spectral resolution than what is normally achieved. The present version of the apparatus associated with the High Frequency Deflection technique is described in this paper from a technical point of view and its performance is discussed.
Etude Expérimentale et Théorique de l'Iode Atomique. Observation du Spectre d'Arc Infrarouge, Classification et Structure Hyperfine
Authors: E Luc-Koenig  , C Morillon  , J Vergès
Published: January 2007

The infrared spectrum of127I, nuclear spinI= 5/2, has been observed between 3 000 and 11 500 cm-1at high resolution by means of the Fourier transform spectrometry method. We have observed 440 structures. Precise measurements of the centre of gravity of these structures give energy levels with an error less than 0.005 cm-1. We have analysed 130 hyperfine structures, giving the magnetic dipole and the electric quadrupole hyperfine structure constants for 37 even levels and 42 odd levels. The intermediate coupling has been studied for the even configurations 5s25p4(6s+ 7s+ 5d+ 6d) + 5s5p6simultaneously, and for the odd configurations 5s25p4(6p+ 7p) and 5s25p44f. Using the wavefunctions obtained, hyperfine structure parametric studies have been performed, giving the H.F.S. monoelectronic constantsa(nl) andb(nl). An a priori study of hyperfine structure, using the relativistic central potential method makes clear the important contribution of relativistic effects and leads one to think that distant configuration interaction effects are negligible in the excited configurations which have been studied.
The Emission Spectrum of SiO: The A-X System in the 2 100-2 300 Å Region
Authors: J L Deutsch  , E W Deutsch  , N Elander  , A Lagerqvist
Published: January 2007

The emission spectrum of SiO has been photographed at high resolution from 2 100 Å to 2 300 Å. Eight bands of theA1II-X1Σ+system have been analysed with special attention to perturbations.
Apropos Trajectories and Quarks
Authors: T Jacobsen
Published: January 2007

Some simple arguments are presented why the trajectory behaviour may be expected if hadrons consist of some constituents like quarks, bound by some range-independent force which may be measured by means of the slope of the trajectories.
Preliminary characterization of the normal microbiota of the human vulva using cultivation-independent methods
Authors: Brown Celeste J. , Wong Mayee , Davis Catherine C. , Kanti Amita , Zhou Xia , Forney Larry J.
Published: January 2007

The objective of this study was to perform a preliminary characterization of the microbial populations of the normal human vulva. Genomic DNA was isolated from samples of the labia majora and labia minora from four healthy women, and sequences of bacterial 16S rRNA genes in each were determined. The sequences were compared with those of known bacterial species to classify the numerically abundant populations in these communities. Even among this limited number of individuals, the microbiota of the human vulva was found to be quite diverse. Each woman had a distinctive microbiota and no single species was common to all women. The microbiota of the labia majora and labia minora differed, although both had appreciable numbers of lactobacilli and strict anaerobes. A greater diversity of populations inhabited the labia majora compared with the labia minora. The results indicated that the microbiota of the vulva includes populations known to be commensals of the microbiota of the skin, colon and vagina, and is much more complex than previously thought, suggesting that more extensive investigations are warranted.
The dominant role of side‐chain backbone interactions in structural realization of amino acid code. ChiRotor: A side‐chain prediction algorithm based on side‐chain backbone interactions
Authors: Spassov Velin Z. , Yan Lisa , Flook Paul K.
Published: January 2007

The basic differences between the 20 natural amino acid residues are due to differences in their side‐chain structures. This characteristic design of protein building blocks implies that side‐chain–side‐chain interactions play an important, even dominant role in 3D‐structural realization of amino acid codes. Here we present the results of a comparative analysis of the contributions of side‐chain–side‐chain (s‐s) and side‐chain–backbone (s‐b) interactions to the stabilization of folded protein structures within the framework of the CHARMm molecular data model. Contrary to intuition, our results suggest that side‐chain–backbone interactions play the major role in side‐chain packing, in stabilizing the folded structures, and in differentiating the folded structures from the unfolded or misfolded structures, while the interactions between side chains have a secondary effect. An additional analysis of electrostatic energies suggests that combinatorial dominance of the interactions between opposite charges makes the electrostatic interactions act as an unspecific folding force that stabilizes not only native structure, but also compact random conformations. This observation is in agreement with experimental findings that, in the denatured state, the charge–charge interactions stabilize more compact conformations. Taking advantage of the dominant role of side‐chain–backbone interactions in side‐chain packing to reduce the combinatorial problem, we developed a new algorithm, ChiRotor, for rapid prediction of side‐chain conformations. We present the results of a validation study of the method based on a set of high resolution X‐ray structures.
Intradermal immunization with ovalbumin‐loaded poly‐ɛ‐caprolactone microparticles conferred protection in ovalbumin‐sensitized allergic mice
Authors: Roman B. S. , Espuelas S. , Gómez S. , Gamazo C. , Sanz M. L. , Ferrer M. , Irache J. M.
Published: January 2007

Background
Although immunotherapy has been reported as the only treatment able to revert the T‐helper type 2 (Th2) response, its administration has some disadvantages such as the requirement of multiple doses, possible side‐effects provoked by conventional adjuvants and the risk of suffering an anaphylactic shock. For these reasons, drug‐delivery systems appear to be a promising strategy due to its ability to (i) transport the allergens, (ii) protect them from degradation, (iii) decrease the number of administrations and (iv) act as immuno‐adjuvants.

Objective
The aim of this work was to evaluate the properties of poly‐ɛ‐caprolactone (PCL) microparticles as adjuvants in immunotherapy using ovalbumin (OVA) as an allergen model. For this purpose, the protection capacity of these microparticles (OVA PCL) against OVA allergy was studied in a murine model.

Methods
The humoral and cellular‐induced immune response generated by OVA encapsulated into PCL microparticles was studied by immunizing BALB/c mice intradermically. Also, OVA‐sensitized mice were treated with OVA PCL and OVA adsorbed to aluminium hydroxide (OVA‐Alum). Fifteen days after therapy, animals were challenged with OVA and different signs of anaphylactic shock were evaluated.

Results
One single shot by an intradermal route with OVA PCL resulted in a Th2‐type immune response. In OVA‐sensitized mice, treatment with OVA PCL elicited high OVA‐specific IgG but low levels of IgE. Furthermore, OVA PCL mice group displayed lower levels of serum histamine and higher survival rate in comparison with the positive control group.

Conclusion
The anaphylactic shock suffered by OVA PCL‐treated mice was weaker than the one induced in the OVA‐Alum group. Hence, the intradermal immunization with OVA PCL microparticles induced hyposensitization in OVA‐allergic mice.
Cytopathological spectrum of unusual malignant pleural effusions at a tertiary care centre in north India
Authors: Awasthi A. , Gupta N. , Srinivasan R. , Nijhawan R. , Rajwanshi A.
Published: January 2007

Background:  Cytological examination of pleural fluid is one of the most informative laboratory procedures in the diagnosis of pleural effusions. Although tuberculosis is the commonest cause of pleural effusions in developing countries, tumours, including grade ones, can present with effusions.

Objective:  The aim of the present study was to evaluate the uncommon causes of malignant pleural effusion.

Methods:  A 2‐year retrospective analysis of pleural fluid cytological specimens submitted to the Department of Cytopathology, PGIMER, Chandigarh between January 2003 and December 2004 was performed to retrieve unusual metastases. Out of a total of 898 samples reviewed, 710 were negative for malignancy and 24 cases were suspicious for malignancy. The remaining 164 cases were positive for malignancy, out of which 38 cases revealed malignancies other than adenocarcinoma.

Results:  The 38 unusual malignancies metastasizing to the pleural cavity included 29 haematological malignancies (non‐Hodgkin's lymphoma, acute lymphoid leukaemia, multiple myeloma and chronic myeloid leukaemia) and nine non‐haematological malignancies (Ewing's sarcoma, neuroblastoma, Wilms’ tumour, squamous cell carcinoma, small‐cell carcinoma and malignant fibrous histiocytoma).

Conclusion:  Although metastatic adenocarcinoma was the commonest aetiology of malignant pleural effusions, a significant number of unusual causes of malignant pleural effusion were also encountered.
How relevant are instantaneous measurements for assessing resource depletion under plant cover? A test on light and soil water availability in 18 herbaceous communities
Authors: VIOLLE C. , LECOEUR J. , NAVAS M.‐L.
Published: January 2007

Quantifying the amount of resources remaining under plant cover is essential for assessing plant–plant interactions or biological invasions. Although resource levels fluctuate in time, their quantification is performed mainly by instantaneous measurements. We investigated how instantaneous measurements are related to the amount of resources cumulated throughout one growing season, measuring parameters of both light and soil water depletion.

During a growing season, we measured regularly light and soil water levels under the cover of 18 plant species grown as monocultures in a common garden. The temporal dynamics of light and soil water depletion were assessed within each monoculture using mechanistic modelling approaches.

The total amounts of resources remaining over the year under the range of communities were best predicted by instantaneous measurements performed at critical periods, differing among resources. The significance of prediction decreased dramatically for other dates, including the period of peak production, but without changing the ranking of communities according to ability to deplete resources. We therefore recommend that such measurements should be limited to qualitative studies, and that mechanistic modelling for quantitative assessments should be developed.
Expression of mucosal chemokines TECK/CCL25 and MEC/CCL28 during fetal development of the ovine mucosal immune system
Authors: Meurens François , Whale Julia , Brownlie Robert , Dybvig Tova , Thompson David R. , Gerdts Volker
Published: January 2007

CCL25/TECK and CCL28/MEC are CC chemokines primarily expressed in thymic dendritic cells and mucosal epithelial cells. The cognate receptors of CCL25 and CCL28, CCR9 and CCR10, respectively, are mainly expressed on T and B lymphocytes. In human, mouse and pig, CCL25 and CCL28 play a key role in the segregation and the compartmentalization of the mucosal immune system through recruitment of immune cells to specific locations. However, little is known about their role in the ontogeny of the mucosal immune system during fetal development. In the present paper, we report the cloning and the sequencing of ovine CCL25, CCL28, CCR9 and CCR10 and the subsequent assessment of their mRNA expression by q‐polymerase chain reaction in several tissues, including thymus, gut‐associated lymphoid tissue and mammary gland, from young and adult sheep and in the fetal lamb during the development of the immune system. CCL25 mRNA was highly expressed in thymus and gut while CCL28 mRNA was more expressed in large intestine, trachea, tonsils and mammary gland, especially at the end of gestation. These results are consistent with observations in other species suggesting similar roles for these chemokines in sheep. In fetuses, mRNA of CCL25, CCL28 and their receptors are expressed early in the thymus and mucosal tissues, including the small intestine and the nasal mucosa. Furthermore, their expression increased towards the end of gestation. Consequently, we hypothesize that CCL25 and CCL28 play an important role in the lymphocyte colonization of fetal tissues, enabling the development of a functional immune system.
Recombination and introgression of nuclear and chloroplast genomes between the peat mosses,Sphagnum capillifoliumandSphagnum quinquefarium
Authors: NATCHEVA RAYNA , CRONBERG NILS
Published: January 2007

Haploid hybrid gametophytes are often present at low frequencies in sympatric populations ofSphagnum capillifoliumandSphagnum quinquefarium. We used intersimple sequence repeat (ISSR) markers and polymerase chain reaction–restriction fragment length polymorphism of the trnLUAAintron of the chloroplast genome to reveal the nuclear and chloroplast composition of mature hybrid gametophytes from natural populations and of gametophytes derived from spores of hybrid sporophytes collected in nature. Asymmetrical nuclear inheritance was found in the progeny of the hybrid sporophytes, indicating that only spores with a low level of recombination of parental genomes were viable. A similarly skewed nuclear composition was found among the naturally occurring hybrid gametophytes. All hybrid genomes contained a larger proportion ofS. capillifoliumISSR markers, combined with only two to fiveS. quinquefariummarkers together with a chloroplast haplotype derived fromS. quinquefarium. In this way, a pattern resembling introgression is created within a single generation. Some individuals possessed nuclear genomes typical forS. capillifoliumin combination with the chloroplast haplotype ofS. quinquefarium,possibly indicating backcrossing. Our results indicate that hybridization betweenS. capillifoliumandS. quinquefariumis relatively common, but the resistance of large parts of the genome against heterospecific genes maintains the genetic distinctness of the species. Further evolutionary and phylogenetic consequences of restricted interspecific gene exchange are discussed.