bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Head Orientation on the Variations in the Discrimination of Shading Orientation
Authors: Moshonkina T R
Published: December 2015

We have previously shown that errors in judging the direction from which a smooth surface is illuminated (ie shading orientation) are not random (Moshonkina et al, 1993 Perception22 Supplement, 100), but vary with this direction in a regular manner. In the experiments described here we investigate whether the same regularities occur when the head is tilted—specifically, whether the gravitational or the head frame of reference is predominantly used in estimation of shading orientation.

Stimuli were computer images of spheres (23 deg diameter) presented briefly (for 100 ms, excluding effects of eye movements). The spheres were apparently illuminated from one of 24 directions spaced at equal (15°) intervals around the sphere in the plane of the display. One of these was randomly chosen for each trial. The task was to define the direction of the apparent illumination on a clock scale with half-hour accuracy. The subject's head was either upright or tilted to the left by 30°. Viewing was left monocular.

The errors in the estimation of illumination direction showed the same systematic dependence on ‘true’ direction regardless of head orientation. These regularities can be described as follows. (1) Estimates were most accurate when the shading gradient was along the horizontal axis (ie with the illuminated pole of the sphere on the right or the left), with greater errors when the gradient was along the oblique axis or vertical. (2) With oblique shading, the estimates showed a systematic tendency to bring the illumination direction closer to the horizontal axis than in ‘reality’. (3) The largest errors occurred when the illuminated pole was oriented downwards. This suggests that the gravitational frame is important in the discrimination of shading orientation.

A significant effect of head orientation was observed when the illuminated pole was oriented downwards. The most probable estimation error was −30° with head upright but −60° with head tilted. This difference is opposite to that expected from application of the head frame of reference.
The Characteristics of VEPs Associated with the Accuracy of Recognition of Facial Emotion
Authors: Mikhailova E S , Davidov D V , Oleichik I V
Published: December 2015

While investigating the timing of the N180 wave of human VEPs, we found earlier that correct recognition of facial emotions was characterised by the primary activation of the right fronto-central regions followed by the immediate involvement of the left ones.

The aim of the present study was to analyse the relations between the parameters of the N400 wave, its regional and hemispheric specificity, and the accuracy of emotion recognition. Twenty healthy right-handed subjects and thirty-two untreated psychiatric patients with mild cognitive dysfunction were instructed to recognise the emotional expression of sad, neutral, or laughing faces presented for 80 ms on a computer screen. The amplitude and peak latency of the N400 response were found to be closely related to the accuracy of recognition. In healthy subjects the main difference between error and correct recognition manifested itself in decreased amplitude and shortened latency of the N400 response in frontal and central zones of the left hemisphere ( p<0.001). Compared to healthy subjects, the patients demonstrated both poor recognition and decreased latency and amplitude of the N400 response in the left frontal regions ( p<0.0001). The results suggest that activation of the left fronto-central regions plays a principal role in the final stages of facial emotion identification.
Measuring Frog Visual Acuity by a Novel Method
Authors: Aho A-C
Published: December 2015

The sensory capabilities of animals have usually been measured either by lengthy conditioned discrimination procedures, or by using some specific unconditioned reflex. Amphibian visual acuity has previously been measured only by the latter type of method. Birukow's (1937 Zeitschrift für Vergleichende Physiologie25 92 – 142) optomotor response experiments on the common frog ( Rana temporaria) yielded an acuity of 4.3 cycles deg−1, which is surprisingly high in the sense that the retinal cell mosaics would suggest a substantially lower acuity. I have used a new method of measuring acuity based on the frog's prey-catching behaviour, a behaviour that has proved very useful for investigations of amphibian vision. Leopard frogs ( R. pipiens) were presented with a stimulus screen where two patches of identical black/white vertical grating were seen through two small horizontal oval windows (left and right) in a large screen displaying a horizontal grating pattern. The windows were of ‘mealworm’ size (18 mm long and 7 mm high, with the frog positioned 220 mm from the screen). One of the two vertical gratings was drifting in the window. If resolved, the movement triggered prey-catching behaviour in the frog: orienting, jumping towards the target, and even snapping. The spatial frequency of the two vertical gratings was varied, while the horizontal pattern of the screen was kept constant throughout the experiment. Orienting or jumping towards the moving grating was taken as an indication that the frog was able to resolve the spatial frequency in question. This method yielded a visual acuity of 2.8 cycles deg−1, which is in good agreement with the eye optics and the retinal grain of frogs (very similar for the common frog and the leopard frog). The method in itself implies that this is a ‘functional’ acuity value.
The Effect of the Centre of Moment on Gender Recognition from Biological Motion
Authors: Hirashima S
Published: December 2015

Cutting (1978 Perception7 393 – 405) suggested that the ‘centre of moment’ ( Cm) plays an important role in the perception of biological motion, especially in gender recognition. The aim of the present study was to examine whether observers could detect a difference in gender from the biological motion pattern and to what degree the Cm index was effective in the recognition of gender. Five males and five females (aged 20 to 25 years) walked in front of a camera from left to right to generate point-light walkers. These point-light walkers consisted of 13 moving dots which were generated by the motion of the actual walking humans. The sequences were replayed in the middle of a TV monitor at 30 frames s−1. Thirty subjects (fifteen males and fifteen females) observed ten different point-light walkers which were presented five times in random order. Subjects recognised the gender more correctly in the case of male walkers (70%) than female walkers (52%). The responses were examined for those point-light walkers showing Cm values similar to the Cm for males of 0.56 – 0.57 and the Cm for females of 0.50 – 0.51. It was found that some people could be recognised whereas others could not, even if they had similar Cm values. The Cm index seems to be useful for recognising gender in some point-light walkers but not in others. To conclude, masculine or feminine walking styles are not defined only by differences in the Cm index.
Horizontal and Vertical Composite Effects in Novel Faces
Authors: Costen N P , Kato T , Craw I G , Akamatsu S
Published: December 2015

The composite effect, where the recognition of the upper half of a face is disrupted by a discrepant lower half relative to an isolated half-face, without a corresponding effect for vertical half-faces, provides a ready method of investigating configural information in face recognition. In previous studies purely photographic techniques have been used for composite construction. We investigated the effects of more face-like stimuli, constructed by morphing techniques.

Subjects were trained to identify frontal Japanese faces, and tested on recognition on marked upper, lower, left, and right halves, both as half-faces and with distractors. While response accuracy for the upper and lower composites was lower than those for the relevant halves, there was no such effect for the right - left composites. A familiarity design was used in the second experiment to replicate this result. In the third experiment quarter-faces (top left - bottom right facial quadrants) were used to control for the information present. We found a strong composite effect for the right - left composites, and weaker ones for the top - bottom and quarter composites. In the fourth experiment we examined whether this effect was dependent on the presence of the quarter-composites by presenting them in a second block but found no effect of this manipulation.

It thus appears that although there is a composite effect with faces composed in a shape-free manner, this effect is unstable. Under certain circumstances subjects may convert from a top - bottom relational processing strategy to a right - left strategy. The information used, even with a constant task, is dependent upon the variability of the images involved.
Do Linguistic Categories Affect Colour Perception? A Comparison of English and Turkish Perception of Blue
Authors: Ozgen E , Davies I R L
Published: December 2015

Cultural relativists adduce the variation in colour categories across languages as prima facie evidence for linguistic relativity (language affects thought). However, there have been very few experiments that have gone beyond this observational level to assess the extent and the nature of linguistic differences on colour categorisation and perception. Here, we report experiments comparing English and Turkish speakers using a colour-grouping task and same - different tasks aimed at redressing this lack. Turkish categorises the blue region with two basic colour terms (lacivert ‘dark blue’ and mavi ‘blue’) whereas English has a single basic term. In experiment 1 subjects sorted a representative set of 65 colours into groups on the basis of their perceptual similarity. Native Turkish speakers were significantly more likely than native English speakers to form two distinct blue groups corresponding to the two basic blue terms of Turkish. In the same - different tasks we sought for possible categorical effects: enhanced discrimination across category boundaries and/or reduced discrimination within categories. For successive presentation, Turkish speakers were more accurate than English speakers in judgments of colour pairs that fell on opposite sides of the lacivert - mavi boundary. However, for simultaneous presentation, there was no difference between the two language groups. The results suggest that there are detectable effects of linguistic categories on colour cognition, but the locus of the effect may be in memory rather than perception.
Illuminant and Viewpoint Biases from Embossed Surfaces
Authors: Mamassian P , Landy M S
Published: December 2015

The human visual system uses a-priori constraints for the estimation of surface shape from images. We propose here a robust paradigm to study individual observers' assumptions about the illuminant and viewpoint positions.

In the study of illumination, the stimuli consisted of parallel, sinusoidally shaped, striped regions, alternating between wide and narrow. Narrow stripes alternating between white and black separated the uniform grey stripes, representing slanted edges in light and in shadow. The stimulus had the shape-from-shading ambiguity: either the wide or the narrow stripes could be seen as ‘in-front’, consistent with different assumed tilts of the illuminant. In a brief flash of a randomly oriented stimulus, observers stated whether the narrow or wide stripes appeared in the foreground. The results showed a strong bias for a light-from-above-left assumption (as in Howard et al, 1990 Perception19 523 – 530; Sun and Perona, 1996 Investigative Ophthalmology and Visual Science37 935). This bias was 20 to 30 deg to the left of vertical. Slower reaction times were obtained for more ambiguous figures.

The same shape judgment task was used with an unshaded stimulus where the only depth cue was image contour. The same curvy, striped figure was portrayed with image contours at the edges of the stripes, as well as surface markings orthogonal to the depth variation, resulting in a shape-from-contour cue. We have previously reported indirect evidence for a bias of viewpoint above the object, that is observers interpret surface normals as pointing upward (Mamassian, 1995 Perception24 Supplement, 35). Our observers' shape judgments were consistent with this bias.
Global versus Local Cues for Route Finding in Virtual Environments
Authors: Geiger S , Gillner S , Mallot H A
Published: December 2015

Motivated by the results of Gillner and Mallot (1996 Perception25 Supplement, 93) implying that local views are basic elements for a spatial representation, we studied the role of global versus local landmarks using a route-finding task. Our hypotheses were: (i) A global navigation strategy relying on allocentric movement decisions is used, eg “go from this place towards the chapel on the hill”, or (ii) a local navigation strategy based on view—movement associations is used, eg “at the red building go right”.

We performed an experiment in a computer graphics town based on a hexagonal grid structure. At each intersection we placed three different buildings. We also provided global direction information by placing six global landmarks distributed equally along a mountain range. Subjects had to learn the back and forth route between two buildings, not knowing that after a learning phase the location of buildings at a particular junction would be changed. These changes produced conflicting global and local information. In the test-phase, the subject approached individual junctions in both learned and novel directions and the movement decisions were recorded. In a control condition with unchanged places twenty subjects made correct decisions for 136 of 160 movements. In the experimental conflict condition 123 decisions were consistent with a local and 37 with a global strategy. This supports our previous finding that local views play a dominant role in making route judgements. Approaching a junction from a learned direction leads to more accurate movement decisions than approaching it from a novel direction, even if the global landmarks are available, which provides further support for the local-view hypothesis.
Surface Colour Matching under Conditions of Multiple Illuminants
Authors: Irtel H
Published: December 2015

Most theories of colour constancy assume a flat coloured surface and a single homogenous light source. Natural situations, however, are 3-dimensional (3-D), are hardly ever restricted to a single light source, and object illumination is never homogenous. Here, two special cases of secondary light sources with sharp boundaries were simulated on a computer screen: a house-like 3-D object with colour patches in sunlight and shadow, and a Mondrian-type pattern with a coloured transparency covering some of the colour patches. Subjects made ‘paper’-matches between colour patches in light and shadow and between patches under the transparency and without the transparency. Matching did not depend on whether the simulated lighting condition was natural (yellow light, blue shadow) or artificial (green light, magenta shadow). Patches under a coloured transparency produced lightness constancy but subjects could not discount chromaticity shifts induced by the transparency. The number of context patches (2 vs 6) made no difference, and it made no difference whether the transparency covered the Mondrian completely or only partially. These results indicate that subjects were not able to use local contrast cues at sharp illumination boundaries to discount for the illuminant.
Radial Asymmetry in the Sensitivity of the Blue Mechanism
Authors: Vassilev A
Published: December 2015

In the human retina, the density of blue cones is lower along the nasal horizontal meridian (Curcio et al, 1991 Journal of Comparative Neurology312 610 – 624) than along the other cardinal meridians, but this finding might reflect interpolation between widely spaced data points rather than actual radial asymmetry. Available psychophysical data on the sensitivity of the blue mechanism do not address this question.

In the present study, subjects had to detect a blue test stimulus (wavelength range at half-amplitude 425 – 480 nm, diameter 24 min arc) presented against yellow background (wavelength above 550 nm, 200 cd m−2). The test stimulus was flickering at 5.7 Hz around a mean level of 3 cd m−2 within a Gaussian temporal window with a time constant of 0.2 s. Foveal and parafoveal sensitivity was measured along the vertical and horizontal meridians. Radial asymmetry in the sensitivity of the blue mechanism was observed, in that the known foveal insensitivity also involved part of the nasal horizontal meridian. The dip in the sensitivity map at the fovea was narrower along the vertical than along the horizontal meridian. While these data are in good agreement with the blue-cone density map, the dip in sensitivity is wider than the depression in the density of blue cones at the fovea. Both screening by yellow pigment and effects of stimulus size might contribute to this discrepancy.
Gabor-based Coding and Facial Similarity Perception
Authors: Lyons M J , Morikawa K , Akamatsu S
Published: December 2015

Little is known about how facial representation in the face-selective areas of inferotemporal cortex is built up from the output of earlier visual areas such as primary visual cortex (area V1). We report work on a model of perceived facial similarity based on topographically ordered aggregates of localised, oriented, and spatial-frequency-selective receptive fields characteristic of V1 cells. The receptive fields are approximated with a set of Gabor filters. This Gabor-based code allows representation of the fine differences in texture and configuration needed for facial discrimination processes. Lyons and Morikawa (1996 Investigative Ophthalmology and Visual Science37 910), showed that Gabor-based similarity is a good predictor of facial similarity for comparisons of fairly similar faces but not sufficient to model experience-dependent effects such as the ‘other race effect’.

Here we report results of a study on the effects of image negation on facial similarity perception. Negation of image gray levels interferes with face recognition (Bruce and Lanton, 1994 Perception23 803 – 822) while preserving 2-D facial-shape information. The Gabor similarity measure models non-endstopped complex cells of V1 and is not affected by image negation. One group of subjects judged similarity among a set of normal gray-scale facial images while another group judged similarity between negative images of the same stimuli. Agreement between the model and human subjects did not decrease with image negation. Moreover, human similarity ratings between negative faces were strongly correlated with those between positives. These results support Gabor-based similarity as a model for facial similarity perception.
Functional ‘Tunnel Vision’ in Pattern Classification Learning
Authors: Jüttner M , Rentschler I
Published: December 2015

Visual pattern recognition has been defined in cognitive science as the ability to relate a perceived object to a learned categorical concept (see Rosch and Lloyd, 1978 Cognition and Categorization Hillsdale, NJ: Lawrence Erlbaum). In contrast, physiologists and clinical practitioners often prefer a low-level functional approach, where visual performance is characterised in terms of acuity, visual field, and contrast sensitivity. From a paradigmatic viewpoint, the former definition can be related to tasks of pattern classification, whereas the latter involves tasks of discrimination. We show that this dichotomy concerning perceptual tasks corresponds to dichotomous internal representations that observers develop in such tasks. For a common set of grey-level patterns (compound Gabor signals), we compared performance in classification and discrimination learning in foveal and extrafoveal vision. Learning speed for classification learning was found to be drastically reduced in extrafoveal relative to foveal vision. Discrimination learning of the same signals remained unaffected by viewing condition. Further analysis of the data in terms of a probabilistic prototype model (Rentschler, Juettner, and Caelli, 1994 Vision Research34 669 – 687) showed that internal representations acquired in extrafoveal classification learning are characterised by a distinct reduced perceptual dimensionality. The results suggest that internal representations underlying pattern classification and discrimination arise at distinct cortical levels, and that the former are developed within an extremely narrow visual field essentially restricted to the fovea.
Speed Discrimination in Luminance and Colour Stimuli as a Function of Contrast
Authors: Wuerger S M , Morgan A H
Published: December 2015

We measured speed discrimination for isoluminant red - green and luminance-defined moving stimuli. The horizontal profile of the stimuli was a Gabor function with a carrier frequency of 2 cycles deg−1. The standard stimulus was a luminance stimulus with a fixed speed of 2 deg s−1 and a fixed contrast of 0.1. The comparison stimuli were either luminance stimuli (cone contrasts: 0.05, 0.1, 0.2, 0.4) or chromatic stimuli (cone contrasts: 0.025, 0.05, 0.1). The speed of the comparison stimuli was varied by an adaptive procedure. After each trial the observer indicated which of the 2 intervals contained the slower moving stimulus. The stimuli always moved horizontally and the direction was chosen randomly at each trial.

The main findings were: (i) For luminance stimuli, the perceived speed was independent of contrast (ranging from 0.1 to 0.4). For colour stimuli, the perceived speed increased with contrast for two out of four observers. (ii) The sensitivity for speed discrimination was independent of contrast for luminance and for colour stimuli. (iii) There was no consistent difference in speed discrimination sensitivity between colour and luminance stimuli when the stimuli were equated in cone contrast.
Psychophysiological Basis for Errors in Identification of Degraded Geometric Forms under Conditions of High Information Uncertainty
Authors: Blum B , Bitler A , King-Smith P E
Published: December 2015

Identification of ambiguous geometric forms by human subjects with brief experience or pre-knowledge of the stimulus may call upon Bayesian specialised mechanisms. Subjects were presented with a 2-alternative forced choice between a pair of incomplete geometric figures in conditions with common and varying components. Stimuli of 1, 3, 5, and 6 pixel acuity grades were displayed in iterative order in randomised blocks at 100, 200, 260, and 360 ms exposure times, rotated or upright, under local or global viewing. Analysis of probability of correct identification against stimulus intensity, acuity demand, and stimulus duration revealed: (i) sigmoid or dipper-shaped nonmonotonic psychometric functions; (ii) Poisson-like skewed binomial distributions of errors; and (iii) category-based dependence on the stimulus and its ambiguity. This is attributable to the high uncertainty constraints imposed on tasks sharing and also varying in their stimulus parameters and dimensions. Nonlinearities shown reflect category-based strategies and attention allocation, interactions as a drive for performance stability manifested in equalisation across sub-categories and invariances of errors, with acuity demand accounted for perhaps by mechanisms of differential attention allocation. Two sources of error are apparent: (i) possibly ‘bottleneck of attention’-related and individually varying ‘blink of attention’, with small falls distributed across stimulus intensities, and (ii) ‘lapse of attention’ with large falls on easier tasks, and rightward-skewed deviations from normal Poisson-like binomial distributions ( p<0.001), the high correlation to performance effort suggesting an active process of pay-off.
Perception of Self-Motion Induced by Moving-Dot Patterns: The Interaction of the Stimulating Area and the Speed of the Pattern
Authors: Kano C
Published: December 2015

A linear moving-dot pattern was presented to observers to induce self-motion. A stimulating circular area of more than 28.1 deg diameter induced self-motion perfectly, and even areas ranging from 5.7 deg to 11.4 deg diameter were able to elicit self-motion (Kano, 1995 Perception24 Supplement, 108). In the present study the interactive effects of the size of the stimulating area and the speed of the moving pattern on the perception of self-motion were examined.

Random-dot patterns were moved downward in a circular area on a screen in a dark room. The diameters of the circular area were 5.7, 11.4, 22.6, and 43.6 deg. The speeds of the dot pattern were 9.49, 18.85, 28.07, 36.73, and 45.08 deg s−1. Observers were twenty-six students of Keio University.

When the size of the area became larger and the dot pattern moved faster, self-motion was generally induced with shorter latencies. However, a significant interaction was found between size and speed; for the smallest area (5.7 deg diameter circle) latency was shorter at the lower speeds (9.49 to 28.07 deg s−1) than at the higher speeds (36.73 and 45.08 deg s −1). For the 11.4 deg diameter circle speed had no effect on latency. For the 22.6 deg diameter circle, however, latency decreased with increasing speed. For the 43.6 deg diameter circle latency was very short and constant under the four higher speeds, but remained considerably longer at the lowest speed. The results show that the effect of speed depends on the size of the stimulating area. When the size was large enough, speed had little effect on the latency of self-motion.
Curve Perception by Drivers: Dependence of the Critical Viewing Distance on Planting Structures and the Driver's Experience
Authors: Sugano L
Published: December 2015

The perception of road curves by car drivers was studied in a simulated driving situation. The purpose was to investigate how planting structures along the road would affect the distance at which the curve was clearly perceived by novices and by experienced subjects, respectively. Subjects rated the clarity of the curve percept in different situations on a nominal scale from 1 to 7. Estimations were made under static conditions at the distances 0 m, 100 m, and 200 m before the beginning of the curve. The critical point for a clear percept was found to be at 100 m for novices and at 200 m for experienced drivers. The planting conditions made no difference.
Genotype resistance, inoculum source and environment directly influence development of grey leaf spot (caused by Stemphylium spp.) and yield loss in narrow-leafed lupin (Lupinus angustifolius)
Authors: Ahmad Arbab , Thomas Geoff J. , Barker Susan J. , MacLeod William J.
Published: December 2015

The rediscovery of grey leaf spot (caused by Stemphylium spp.) in narrow-leafed lupins (Lupinus angustifolius L.) in Western Australia in 2007 and identification of susceptible cultivars raised concern about potential impact of this disease in crop production. This study assessed potential yield loss in narrow-leafed lupins and the importance of inoculum source in the development of the disease. In two field experiments, no disease was observed in the resistant cultivar Mandelup, but disease progress was rapid in susceptible genotypes Unicrop and WALAN2333 and resulted in up to 64% yield loss. Disease progress and yield loss were greater in plots inoculated with infested trash than in those with spray-only inoculum. Release of Stemphylium spores from infested trash was monitored during the lupin-growing period by using spore traps and seedling trap plants. Conidia were released continuously throughout the growing period and significant (P < 0.01) correlation was found between the number of conidia captured and the frequency of rain, and between disease severity on trap plants and aerial concentration of conidia. The results confirm that grey leaf spot can severely reduce yield of susceptible narrow-leafed lupin cultivars and that removal or avoidance of previous season trash will be important in preventing spread of the disease.
Use of thermographic imaging to screen for drought-tolerant genotypes in Brachypodium distachyon
Authors: Ruíz Magdalena , Quemada Miguel , García Rosa M. , Carrillo José M. , Benavente Elena
Published: December 2015

Thermal imaging has been used to evaluate the response to drought and warm temperatures in a collection of Brachypodium distachyon lines adapted to varied environmental conditions. Thermographic records were able to separate lines from contrasting rainfall regimes. Genotypes from dryer environments showed warmer leaves under water deficit, which suggested that decreased evapotranspiration was related to a more intense stomatal closure. When irrigated and under high temperature conditions, drought-adapted lines showed cooler leaves than lines from wetter zones. The consistent, inverse thermographic response of lines to water stress and heat validates the reliability of this method to assess drought tolerance in this model cereal. It additionally supports the hypothesis that stomatal-based mechanisms are involved in natural variation for drought tolerance in Brachypodium. The study further suggests that these mechanisms are not constitutive but likely related to a more efficient closing response to avoid dehydration in adapted genotypes. Higher leaf temperature under water deficit seems a dependable criterion of drought tolerance, not only in B. distachyon but also in the main cereal crops and related grasses where thermography can facilitate high-throughput preliminary screening of tolerant materials.
Tracer experiment using 42K+ and 137Cs+ revealed the different transport rates of potassium and caesium within rice roots
Authors: Kobayashi Natsuko I. , Sugita Ryohei , Nobori Tatsuya , Tanoi Keitaro , Nakanishi Tomoko M.
Published: December 2015

The differences in the transport characteristics in planta between potassium (K+) and caesium (Cs+) was investigated using their radionuclides, 42K+ and 137Cs+. A tracer experiment using nutrient solutions supplemented with 42K and 137Cs revealed that the ratio of the root’s K+ uptake rate to its Cs+ uptake rate was 7–11 times higher than the K+ : Cs+ concentration ratio in the solution, and the number was varied depending on the K concentration in the solution and also on the growth condition. After entering through the root tissues, the 42K+ : 137Cs+ ratio in the shoots was 4.28 times higher than the value in the roots. However, the 42K+ : 137Cs+ ratio in each leaf did not differ significantly, indicating that the primary transport of K+ and Cs+ in the shoots are similarly regulated. In contrast, among the radionuclides stored in the roots over 4 h, 30% of the 42K+ was exported from the roots over the following hour, whereas only 8% of 137Cs+ was exported. In addition, within the xylem, K+ was shown to travel slowly, whereas Cs+ passed quickly through the roots into the shoots. In conclusion, our study demonstrated very different transport patterns for the two ions in the root tissues.
Infecting Pacific Herring with Ichthyophonus sp. in the Laboratory
Authors: Hershberger P. K. , Hart L. M. , MacKenzie A. H. , Yanney M. L. , Conway C. M. , Elliott D. G.
Published: December 2015

The protistan parasite Ichthyophonus sp. occurs in coastal populations of Pacific Herring Clupea pallasii throughout the northeast Pacific region, but the route(s) by which these planktivorous fish become infected is unknown. Several methods for establishing Ichthyophonus infections in laboratory challenges were examined. Infections were most effectively established after intraperitoneal (IP) injections with suspended parasite isolates from culture or after repeated feedings with infected fish tissues. Among groups that were offered the infected tissues, infection prevalence was greater after multiple feedings (65%) than after a single feeding (5%). Additionally, among groups that were exposed to parasite suspensions prepared from culture isolates, infection prevalence was greater after exposure by IP injection (74%) than after exposure via gastric intubation (12%); the flushing of parasite suspensions over the gills did not lead to infections in any of the experimental fish. Although the consumption of infected fish tissues is unlikely to be the primary route of Ichthyophonus sp. transmission in wild populations of Pacific Herring, this route may contribute to abnormally high infection prevalence in areas where juveniles have access to infected offal.

Received June 25, 2015; accepted September 12, 2015
Comparative studies on the fish-killing activities of Chattonella marina isolated in 1985 and Chattonella antiqua isolated in 2010, and their possible toxic factors
Authors: Cho Kichul , Sakamoto Jun , Noda Tatsuki , Nishiguchi Tomoki , Ueno Mikinori , Yamasaki Yasuhiro , Yagi Motoaki , Kim Daekyung , Oda Tatsuya
Published: December 2015

Chattonella antiqua isolated in 2010 showed extremely more potent fish-killing activities against red sea bream, Japanese horse mackerel, and blue damselfish than those of Chattonella marina isolated in 1985. Chemiluminescence and electron spin resonance (ESR) analyses suggested greater reactive oxygen species (ROS)-producing activity of C. antiqua than that of C. marina. Sodium benzoate, a hydroxyl radical scavenger, significantly suppressed the fish-killing activity of C. antiqua on blue damselfish. The chlorophyll level in the gill tissue of blue damselfish exposed to flagellate cells increased along with the exposure time, and the cell count of gill-associated C. antiqua estimated with chlorophyll level was higher than that of C. marina. These results suggest that the ROS-producing activity and affinity of Chattonella cells to the gill surface may be important factors influencing the fish-killing activity of Chattonella species.
Canonical symplectic particle-in-cell method for long-term large-scale simulations of the Vlasov–Maxwell equations
Authors: Qin Hong , Liu Jian , Xiao Jianyuan , Zhang Ruili , He Yang , Wang Yulei , Sun Yajuan , Burby Joshua W. , Ellison Leland , Zhou Yao
Published: December 2015

Particle-in-cell (PIC) simulation is the most important numerical tool in plasma physics. However, its long-term accuracy has not been established. To overcome this difficulty, we developed a canonical symplectic PIC method for the Vlasov–Maxwell system by discretising its canonical Poisson bracket. A fast local algorithm to solve the symplectic implicit time advance is discovered without root searching or global matrix inversion, enabling applications of the proposed method to very large-scale plasma simulations with many, e.g. 109, degrees of freedom. The long-term accuracy and fidelity of the algorithm enables us to numerically confirm Mouhot and Villani’s theory and conjecture on nonlinear Landau damping over several orders of magnitude using the PIC method, and to calculate the nonlinear evolution of the reflectivity during the mode conversion process from extraordinary waves to Bernstein waves.
Evolutionary cell biology: functional insight from “endless forms most beautiful”
Authors: Richardson Elisabeth , Zerr Kelly , Tsaousis Anastasios , Dorrell Richard G. , Dacks Joel B.
Published: December 2015

In animal and fungal model organisms, the complexities of cell biology have been analyzed in exquisite detail and much is known about how these organisms function at the cellular level. However, the model organisms cell biologists generally use include only a tiny fraction of the true diversity of eukaryotic cellular forms. The divergent cellular processes observed in these more distant lineages are still largely unknown in the general scientific community. Despite the relative obscurity of these organisms, comparative studies of them across eukaryotic diversity have had profound implications for our understanding of fundamental cell biology in all species and have revealed the evolution and origins of previously observed cellular processes. In this Perspective, we will discuss the complexity of cell biology found across the eukaryotic tree, and three specific examples of where studies of divergent cell biology have altered our understanding of key functional aspects of mitochondria, plastids, and membrane trafficking.
What cell biologists should know about the National Institutes of Health BRAIN Initiative
Authors: Insel Thomas R. , Koroshetz Walter
Published: December 2015

The BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative is an ambitious project to develop innovative tools for a deeper understanding of how the brain functions in health and disease. Early programs in the National Institutes of Health BRAIN Initiative focus on tools for next-generation imaging and recording, studies of cell diversity and cell census, and integrative approaches to circuit function. In all of these efforts, cell biologists can play a leading role.
Fishing impacts on benthic ecosystems: an introduction to the 2014 ICES symposium special issue
Authors: Buhl-Mortensen Lene , Neat Francis , Koen-Alonso Mariano , Hvingel Carsten , Holte Børge
Published: December 2015

Understanding the impacts of fishing on the seabed is a basic requirement for ecosystem-based marine management. It is only recently that we have begun understanding how fisheries-driven perturbations affect ecosystem function, biodiversity, productivity, and resilience. Technical solutions aimed at minimizing seabed impacts are starting to appear, but their efficacy remains to be demonstrated. In 2014, ICES held a symposium on the effects of fishing on benthic fauna, habitat, and ecosystem function, in Tromsø, Norway. The main goals of the symposium were to summarize current understanding of the physical and biological effects of fishing activities on benthic ecosystems, and to review the diversity of technical measures currently available to mitigate these effects. Here, we briefly describe the background to the scientific symposium and highlight the main contributions.
Pepino mosaic virusRNA-Dependent RNA Polymerase POL Domain Is a Hypersensitive Response-Like Elicitor Shared by Necrotic and Mild Isolates
Authors: Sempere Raquel N. , Gómez-Aix Cristina , Ruíz-Ramón Fabiola , Gómez Pedro , Hasiów-Jaroszewska Beata , Sánchez-Pina María Amelia , Aranda Miguel A.
Published: December 2015

Pepino mosaic virus (PepMV) is an emerging pathogen that represents a serious threat to tomato production worldwide. PepMV-induced diseases manifest with a wide range of symptoms, including systemic necrosis. Our results showed that PepMV accumulation depends on the virus isolate, tomato cultivar, and environmental conditions, and associates with the development of necrosis. Substitution of lysine for glutamic acid at position 67 in the triple gene block 3 (TGB3) protein, previously described as a necrosis determinant, led to increased virus accumulation and was necessary but not sufficient to induce systemic necrosis. Systemic necrosis both in tomato and Nicotiana benthamiana shared hypersensitive response (HR) features, allowing the assessment of the role of different genomic regions on necrosis induction. Overexpression of both TGB3 and the polymerase domain (POL) of the RNA-dependent RNA polymerase (RdRp) resulted in necrosis, although only local expression of POL triggered HR-like symptoms. Our results also indicated that the necrosis-eliciting activity of POL resides in its highly conserved “palm” domain, and that necrosis was jasmonic acid-dependent but not salicylic acid-dependent. Altogether, our data suggest that the RdRp-POL domain plays an important role in PepMV necrosis induction, with necrosis development depending on the virus accumulation level, which can be modulated by the nature of TGB3, host genotype and environmental conditions.
Genetic recombination as DNA repair
Authors: Parkhomchuk Dmitri , Shadrin Alexey , McHardy Alice C.
Published: December 2015

Maintenance of sexual reproduction and genetic recombination imposes physiological costs when compared to parthenogenic reproduction, most prominently: for maintaining the corresponding (molecular) machinery, for finding a mating partner, and through the decreased fraction of females in a population, which decreases the reproductive capacity. Based on principles from information theory, we have previously developed a new population genetic model, and applying it in simulations, we have recently hypothesized that all species maintain the maximum genomic complexity that is required by their niche and allowed by their mutation rate and selection intensity. Applying this idea to the complexity overhead of recombination maintenance, its costs must be more than compensated by an additional capacity for complexity in recombining populations. Here, we show a simple mechanism, where recombination helps to maintain larger biases of alleles frequencies in a population, so the advantageous alleles can have increased frequency. This allows recombining populations to maintain higher fitness and phenotypic efficiency in comparison with asexual populations with the same parameters. Random mating alone already significantly increases the ability to maintain genomic and phenotypic complexity. Sexual selection provides additional capacity for this complexity. The model can be considered as a unifying synthesis of previous hypotheses about the roles of recombination in Muller's ratchet, mutation purging and Red Queen dynamics, because the introduction of recombination both increases population frequencies of beneficial alleles and decreases detrimental ones. In addition, we suggest simple explanations for niche-dependent prevalence of transient asexuality and the exceptional asexual lineage ofBdelloid rotifers.
Genomic and Chemical Diversity inCannabis
Authors: Lynch Ryan C. , Vergara Daniela , Tittes Silas , White Kristin , Schwartz C.J. , Gibbs Matthew J. , Ruthenburg Travis C. , deCesare Kymron , Land Donald P. , Kane Nolan C.
Published: December 2015

Plants of theCannabisgenus are the only producers of phytocannabinoids, terpenoid compounds that strongly interact with evolutionarily ancient endocannabinoid receptors shared by most bilaterian taxa. For millennia, the plant has been cultivated for these compounds, but also for food, rope, paper, and clothing. Today, specialized varieties yielding high-quality textile fibers, nutritional seed oil or high cannabinoid content are cultivated across the globe. However, the genetic identities and histories of these diverse populations remain largely obscured. We analyzed the nuclear genomic diversity among 340Cannabisvarieties, including fiber and seed oil hemp, high cannabinoid drug-types and feral populations. These analyses demonstrate the existence of at least three major groups of diversity, with European hemp varieties more closely related to narrow leaflet drug-types (NLDT) than to broad leaflet drug-types (BLDT). The BLDT group appears to encompass less diversity than the NLDT, which reflects the larger geographic range of NLDTs, and suggests a more recent origin of domestication of the BLDTs. As well as being genetically distinct, hemp, NLDT and BLDT genetic groups each produce unique cannabinoid and terpenoid content profiles. This combined analysis of population genomic and trait variation informs our understanding of the potential uses of different genetic variants for medicine and agriculture, providing valuable insights and tools for a rapidly emerging, valuable legal industry.
Can the two Asian giants reach a political settlement?
Authors: Kapur Ashok
Published: December 2015

Purpose

– The purpose of this paper is to outline the history of the Sino-Indian conflict and to evaluate recent changes as reflected in the high level meetings between President Xi Jinping and Prime Minister Narendra Modi. It explores the evolving relationship in terms of three types of bargaining: elusive, tacit and convergent.

Design/methodology/approach

– By adopting a historical approach one gets a better sense of the evolving pattern of relations between China and India and the circumstances in which the evolution is occurring.

Findings

– China-India relations are similar to a journey where the progress is measured in terms of small steps rather than a final peace settlement. Relations have changed slowly towards a positive direction in economic relations, and there is a pattern of stability in border talks but the issue is complicated by the linkages between the Tibet question and border issues.

Research limitations/implications

– This topic requires considerable research because it is important for the future of Asian international relations and it is under-researched. Perhaps there could be an edited volume which brings together researchers from different backgrounds and expertise. The suggested work must be empirical but with a theoretical framework related to different types of bargaining cultures and experiences in Asia.

Originality/value

– As China and India evolve in their diplomatic practices and thinking, as Asian powers are readjusting their policies in the light of new circumstances, there are insights for policy analysts and practitioners in China and India among other Asian countries.
Serendipity in legal information seeking behavior
Authors: Solomon Yosef , Bronstein Jenny
Published: December 2015

Purpose

– The purpose of this paper is to investigate the role of serendipity in legal information seeking behavior of family law advocates, whom act in a challenging information environment that lacks published court rulings.

Design/methodology/approach

– A quantitative research using a web-based structured questionnaire, among Israeli family law advocates. Single stage systematic sampling, with random starting point and no recurring pattern of each sixth family law advocate on the Israel Bar Advocates List, was applied. Data from 135 Israeli family law advocates were used for analysis.

Findings

– Electronic information sources were found as most serendipitous; family law advocates were identified as super encounterers; four types of professional background concerns and seven legal professional contributions of the unexpected encounters with court rulings, were identified. Furthermore, findings support several frameworks presented on earlier information encounter literature.

Research limitations/implications

– Data absence on demographic and professional variables distributions of Israeli family law advocates was a limiting factor, compensated by the systematic sampling method used, thus can be regarded to reflect the views of the entire study population. Surveys’ reliance on self-reporting recalls of serendipitous events is also a limiting factor, though predicted and acceptable in this matter since chance encounters occur unexpectedly and are complex to capture.

Practical implications

– Chance encounters may expose lawyers to meaningful information it is unlikely they were able to find because its limited publication, and assist them keep up with current law for better serves their clients.

Originality/value

– The study augments the current empirically based knowledge on serendipity and provides insights into legal information chance encounters among a little-studied group of knowledge workers: family law advocates.