bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Scanning in the Lateral Eyes of the Copepod Copilia
Authors: Downing A C 
Published: January 2007

The lateral eyes of the female Copilia are exceptionally large for a creature of its size but have very few receptors. These receptors appear to scan the image plane of the anterior lenses of the eye, but until now there has been no behavioural evidence linking their movement positively with the functioning of the eyes, though there is some (disputed) evidence that it is merely a side-effect of peristalsis. On channel-capacity grounds we might not have expected optical scanning to occur in biological systems, so any positive evidence for scanning, in the engineering sense, is particularly interesting. Optical measurements of the position of the image plane, in live intact female Copilia quadrata, generally corroborate Exner's (1891) finding that an image is in focus at the plane of the distal ends of the receptors, though the position of best focus seems slightly in front of a second lens, behind which the receptor structure lies. An alternative optical schema of Wolken and Florida (1969) is disproved. The position of focus satisfies minimal optical conditions for scanning. Movements of a coloured stripe pattern, used as a test object for the optical measurements, elicited the putatively scanning movements of the receptor structure, suggesting strongly that these really are an intrinsic part of normal visual functioning, not an epiphenomenon. It was also discovered that intermittent swimming movements of the limbs tend to be preceded by these photoreceptor movements. Both findings support the hypothesis that Copilia's eye is an optical scanning system.
Troubles de l'orientation spatiale dans une épreuve de recherche d'itinéraire lors des lésions corticales unilaterales
Authors: Hécaen H , Tzortzis C , Masure M C 
Published: January 2007

Previous studies on brain-damaged patients have shown impairments in orientation. When the results have been based on a route-finding test the impairment was found in both left and right parietal lesion groups, while when maze tests have been used, the impairment correlated clearly only with lesions of the right hemisphere. In the present study the route-finding test was given to 77 right-handed patients with unilateral cortical lesions (33 right-sided, and 44 left-sided), and to 24 controls. In order to evaluate the possible influence of kinesthetic afferents, the test was carried out under two different conditions: active (walking) and passive (in a pushchair). The results show the performances of subjects with lesions on the left side are significantly poorer than those of the controls, but better than those of subjects with lesions on the right side. For both groups the impairment associated with the lesion is the same under active and passive conditions, which does not support the hypothesis of the possible role of the kinesthetic afferents. Posterior lesions produce significantly more failures in both groups. The importance of the parietal lobe, however, was clearly seen only in subjects with lesions on the right side.
Relations entre vision binoculaire, développement moteur et cognitif, et EEG
Authors: Harrison-Covello Adèle , Lairy Gabrielle C 
Published: January 2007

Un premier groupe de 58 enfants d'âge scolaire adressés à un service spécialisé dans le traîtement des troubles de la psychomotricité et du langage a été soumis a une série d'investigations ophtalmologiques, cliniques et EEG. Ces sujets ont été comparés à un deuxième groupe de 45 enfants strabiques de même âge, adressés à un département d'ophtalmologie, et soumis aux mêmes examens cliniques et EEG. Parmi les sujets du premier groupe, 43% se sont révélés avoir des troubles de la fonction binoculaire; parmi les enfants du deuxième groupe (sans vision binoculaire), la proportion de troubles psychomoteurs et cognitifs importants n'atteint que le tiers de sa valeur dans le premier groupe. L'analyse EEG des deux groupes a été faite par rapport à la qualité de la vision binoculaire, au degré de perturbation clinique et à l'anamnèse. Cette analyse montre: une nette relation entre foyers occipitaux de pointes et trouble (ou absence) de la vision binoculaire; entre désorganisation spatio-temporelle du rythme de fond, degré de perturbation clinique et anamnèse chargée. Les inter-relations entre perturbations de la fonction binoculaire, développement cognitif et EEG sont discutées et quelques conséquences pratiques de cette étude sont ébauchées.
Selective Attention in Hearing and Vision
Authors: McDonnell P M , Perusse Sandra 
Published: January 2007

Two experiments employed dichotic listening and a visual analogue of dichotic listening. Detection of signals on a nonattended channel deteriorated for both modalities as the signal rate increased. However, deterioration in the primary task, vocal shadowing, was greater for auditory presentations. A third study showed that modality differences disappeared when shadowing difficulties were equated. In addition, it was argued from experiments 1 and 2 that increasing signal rate led to an increase in the selectivity of attention. At the point where shadowing began to deteriorate there was evidence of reciprocity or trading relations between primary and secondary tasks.
The Microstructure of Dual Task Interaction. 2. The Effect of Task Instructions on Attentional Allocation and a Model of Attention-Switching
Authors: Fisher Shirley 
Published: January 2007

As an extension of an experimental design reported previously the microstructure of dual task interaction was investigated in a condition in which task instructions favoured the task which had previously been designated the secondary task. In the situation explored in this paper subjects worked on the five-choice serial reaction task (designated secondary task) whilst at the same time they received single auditory digits at random time intervals, performed a transform operation (adding seven), and called the answer out into a voice key. The nature of the interaction was investigated using fine analysis of data, and it is argued that the results give further support to the view that subjects were processing information sequentially. A change in the patterning of serial responses in the interval defined by the digit stimulus ( Ds) and the digit response ( Dr) under the changed-instructions condition suggested that individuals are able to play an active role in the ordering of the attention process in sequential processing situations. ‘Process theory’, in which the information processing state of the main task is considered to have a direct influence on the response to the secondary task signal, is argued to be of little use in explaining the data. Two types of explanations based on criterion theory are considered—one which involves criterion setting with respect to a direct time base and one which relies on information processing stage, as an indirect time base. It is argued that the microstructure of dual task interaction should be investigated more closely and that the ordering of the time-sharing process is a skill.
Representational Drawings of Solid Objects by Young Children
Authors: Chen May Jane , Cook Michael 
Published: January 2007

Two groups of children aged 6 and 8 years were given three tasks requiring graphical representations of solid geometric forms. These tasks were drawing from life models, copying from photographs, and copying from line drawings of these objects. Performance was assessed on the basis of level of approximation to correct perspective. Older children used more perspective features than younger children in their drawings. At all ages, the drawings from life were most difficult. Results on the two copying tasks were not consistent. Drawings made by copying photographs were either as advanced as or poorer than copies of line drawings. The results are explained in terms of the difficulties exhibited by young children in translating the three-dimensional scene to a two-dimensional picture plane and strategies adopted by them to cope with these problems.
The Perception of Complex Patterns by Touch
Authors: Millar Susanna 
Published: January 2007

Two experiments are reported on matching Braille characters in dot pattern and outline shape formats by congenitally blind subjects. In a third experiment subjects' drawings of Braille shapes were analysed. Experiment 1 showed that normal and retarded readers differed significantly when outline shapes ‘cued’ identical dot patterns, but did not differ when the dot patterns preceded outlines. However, normal as well as retarded readers were faster and more accurate in judging identical pairs in dot-pattern format than in any other condition. In experiment 2 dot patterns and outline shapes were matched at three levels of reading proficiency. Faster readers made fewer errors in matching identical pairs, but all subjects were more accurate and faster with dot patterns than with outline shapes. Experiment 3 showed that blind subjects' drawing of outline shapes is not affected by reading proficiency. Most common were errors of alignment, including ‘rotation’ from vertical to horizontal axes, suggesting that sources of confusion were spatial position of dots and major axes of alignment rather than mirror-image reversals. It is argued that the results are not compatible with the hypothesis that Braille letters are perceived as global outline shapes by faster readers.
Temporal Competition between Odorants: Effect of Different Time Intervals on the Perception of Monorhinic and Dichorhinic Binary Mixtures
Authors: Rouby Catherine , Holley André 
Published: January 2007

Backward masking and its possible connection with the perception of odour mixtures has been investigated. Temporal competition between odorants in a binary mixture was tested by artificially creating a delay between one odour (the target) and a second, stronger, odour (the mask) during a single natural sniff. To test the influence of central versus peripheral competition, the same mixture was presented either monorhinically or dichorhinically. The delay (100 to 400 ms) did not influence intensity perception, indicating that intensities are integrated during the sniff irrespective of the temporal arrangement. In contrast, the number of qualities perceived was influenced by the delay: delays of 200 to 400 ms gave significant increases in the frequency of detection of a mixture, whereas synchronous mixtures favoured the perception of a single odour. Masking was also significantly stronger in dichorhinic mixtures. These effects are discussed in terms of retroactive masking which seems to be enhanced by dichorhinic mixtures, suggesting that masking has an important central component.
The Effects on Bilateral-Symmetry Detection of Multiple Symmetry, near Symmetry, and Axis Orientation
Authors: Wenderoth Peter 
Published: January 2007

Palmer and Hemenway (1978 Journal of Experimental Psychology: Human Perception and Performance4 691–702) reported that shapes with multiple axes of symmetry are processed faster than those with single symmetry even when trials are blocked so that the subject knows that any symmetry axis will be vertical. Because their model of symmetry detection postulated a two-stage process in which all orientations are searched crudely at first, in no particular order, followed by second-stage scrutiny, the continued salience of multiple over single symmetry with blocking could not be explained. They claimed that stimuli with multiple axes of symmetry have an additional ‘goodness’. Four experiments are reported in which it is demonstrated that both sensitivity ( d′) and response bias ( β) vary considerably in symmetry detection, not just as a function of the positive (symmetrical) stimuli used but also as a function of the negative or conjugate instances selected. Although stimuli with multiple axes of symmetry may well have extra salience due to pattern ‘goodness’, this factor may have been confounded with response bias in Palmer and Hemenway's experiments. It is suggested that several of their—as well as other researchers—results could be due to some combination of the effects of type of positive stimulus, type of negative stimulus, and response bias directed towards responding positively to highly symmetrical stimuli in a mix of less symmetrical stimuli. Palmer and Hemenway appear to have been correct in suggesting that subjects are more sensitive to quadruple than single symmetry, but the experiments indicate that subjects are also more willing to respond “symmetrical” to stimuli with quadruple symmetry when trials are not blocked, as in Palmer and Hemenway's experiment 1. However, it is demonstrated that the latter effect can be removed by blocking trials so that only one class of symmetrical pattern and one class of asymmetrical pattern occur in any block.
Spatial Scale Interactions in Stereo Sensitivity and the Neural Representation of Binocular Disparity
Authors: Smallman Harvey S , MacLeod Donald I A 
Published: January 2007

How are binocular disparities encoded and represented in the human visual system? An ‘encoding cube’ diagram is introduced to visualise differences between competing models. To distinguish the models experimentally, the depth-increment-detection function (discriminating disparity d from d ± Δ d) was measured as a function of standing disparity ( d) with spatially filtered random-dot stereograms of different centre spatial frequencies. Stereothresholds degraded more quickly as standing disparity was increased with stimuli defined by high rather than low centre spatial frequency. This is consistent with a close correlation between the spatial scale of detection mechanisms and the disparities they process. It is shown that a simple model, where discrimination is limited by the noisy ratio of outputs of three disparity-selective mechanisms at each spatial scale, can account for the data. It is not necessary to invoke a population code for disparity to model the depth-increment-detection function. This type of encoding scheme implies insensitivity to large interocular phase differences. Might the system have developed a strategy to disambiguate or shift the matches made at fine scales with those made at the coarse scales at large standing disparities? In agreement with Rohaly and Wilson, no evidence was found that this is so. Such a scheme would predict that stereothresholds determined with targets composed of compounds of high and low frequency should be superior to those of either component alone. Although a small stereoacuity benefit was found at small disparities, the more striking result was that stereothresholds for compound-frequency targets were actually degraded at large standing disparities. The results argue against neural shifting of the matching range of fine scales by coarse-scale matches posited by certain stereo models.
On the relationship between sequence and structure similarities in proteomics
Authors: Krissinel Evgeny 
Published: January 2007

AbstractMotivation: The underlying assumption of many sequence-based comparative studies in proteomics is that different aspects of protein structure and therefore functionality may be linked to particular sequence motifs. This holds true if sequence similarity is sufficiently high, but in general the relationship between protein sequence and structure appears complex and is not well understood.Results: Statistical analysis of multiple and pairwise structural alignments of protein structures within SCOP folds is performed. The results indicate that multiple conservation of residue identity is not common and that relationship between sequence and structure may be explained by a model based on the assumption that protein structure is tolerant to residue substitutions preserving hydropathic profile of the sequence. This model also explains the origin and specific value of the sequence similarity threshold, noticed in many previous studies, below which structural resemblance is not statistically expected.Contact: keb@ebi.ac.ukkeb
The Pam18/Tim14–Pam16/Tim16 complex of the mitochondrial translocation motor: The formation of a stable complex from marginally stable proteins
Authors: Iosefson Ohad , Levy Ran , Marom Milit , Slutsky‐Leiderman Olga , Azem Abdussalam 
Published: January 2007

AbstractThe vast majority of mitochondrial proteins are imported from the cytosol. For matrix‐localized proteins, the final step of translocation across the inner membrane is mediated by the mitochondrial translocation motor, of which mhsp70 is a key component. The ATP‐dependent function of mhsp70 is regulated by a complex, composed of a J‐protein (called Pam18 or Tim14) and a J‐like protein (called Pam16 or Tim16), and the nucleotide exchange factor Mge1. In this study, we investigated the structural properties of a recombinant purified Pam18/Tim14–Pam16/Tim16 complex using cross‐linking with the bifunctional reagent DSS and CD‐spectroscopy. The results of the study show that both Pam18/Tim14 and Pam16/Tim16 are thermally unstable proteins that unfold at very low temperatures (Tm values of 16.5°C and 29°C, respectively). Upon mixing the proteins in vitro, or when both proteins are co‐overexpressed in bacteria, Pam18/Tim14 and Pam16/Tim16 form a heterodimer that is thermally more stable than the individual proteins (Tm = 41°C). Analysis of the properties of the complex in GdnHCl shows that dissociation of the heterodimer is the limiting step in achieving full denaturation.
Semisynthesis of unnatural amino acid mutants of paxillin: Protein probes for cell migration studies
Authors: Vogel Elizabeth M. , Imperiali Barbara 
Published: January 2007

AbstractCaged phosphopeptides and phosphoproteins are valuable tools for dissecting the dynamic role of phosphorylation in complex signaling networks with temporal and spatial control. Demonstrating the broad scope of phosphoamino acid caging for studying signaling events, we report here the semisynthesis of a photolabile precursor to the cellular migration protein paxillin, which is a complex, multidomain phosphoprotein. This semisynthetic construct provides a powerful probe for investigating the influence that phosphorylation of paxillin at a single site has on cellular migration. The 61‐kDa paxillin construct was assembled using native chemical ligation to install a caged phosphotyrosine residue at position 31 of the 557‐residue protein, and the probe includes all other binding and localization determinants in the paxillin macromolecule, which are essential for creating a native environment to investigate phosphorylation. Following semisynthesis, paxillin variants were characterized through detailed biochemical analyses and by quantitative uncaging studies.
Interleukin‐9 and Interleukin‐13 augment UTP‐induced Cl ion transport via hCLCA1 expression in a human bronchial epithelial cell line
Authors: Endo Y. , Isono K. , Kondo M. , Tamaoki J. , Nagai A. 
Published: January 2007

SummaryBackground
IL‐9 and IL‐13 induce airway goblet cell metaplasia, which is associated with expression of a Ca2+‐activated Cl channel, hCLCA1.Objective
As UTP stimulates both mucin secretion and Cl ion transport via a Ca2+‐dependent pathway, the purpose of this study is to determine whether IL‐9 and IL‐13 affect UTP‐induced Cl ion transport in human bronchial epithelial cell line 16HBE cells, and if they do, to elucidate whether such an effect is associated with hCLCA1 expression.Methods
The increases in short‐circuit current (Isc) in response to UTP were measured in the presence of amiloride by the Ussing chamber method. The morphology of epithelial cells was assessed by light microscopic findings, and hCLCA1 expression was investigated by immunocytochemistry and immunoblotting.Results
UTP‐induced increases in Isc in the cells treated with IL‐9 or IL‐13 for 48 h were greater than those in non‐treated cells, and the potency of IL‐13 was greater than that of IL‐9. Pre‐treatment with Ca2+‐activated Cl channel inhibitors diisothocyanatostilbene‐2, 2‐disulphonic acid and niflumic acid completely inhibited the augmenting effects of IL‐9 and IL‐13 on Isc. The epithelial layer of the cells treated with IL‐9 or IL‐13 was thicker than that of non‐treated cells. The expression of hCLCA1 protein was induced by IL‐13 in a concentration‐dependent manner. These effects of IL‐13 were more potent than those of IL‐9.Conclusion
IL‐9 and IL‐13 augmented UTP‐induced Cl ion transport, probably via proliferation of the cells with hCLCA1 expression, and IL‐13 was more potent than IL‐9 in producing such an effect in 16HBE cells.
Supplementation with vitamins C, E, β‐carotene and selenium has no effect on anti‐oxidant status and immune responses in allergic adults: a randomized controlled trial
Authors: Dunstan J. A. , Breckler L. , Hale J. , Lehmann H. , Franklin P. , Lyons G. , Ching S. Y. L. , Mori T. A. , Barden A. , Prescott S. L. 
Published: January 2007

SummaryBackground
Anti‐oxidants are of growing interest in early treatment and prevention of allergic diseases in early life, but the effects on allergen‐specific immune responses need to be documented further before intervention studies in infants are undertaken. The aim of this study in adults was to determine the effects of dietary anti‐oxidants on allergen‐specific immune responses in sensitized individuals.Methods
In a randomized controlled trial, 54 allergic adults received an anti‐oxidant supplement (n=36) comprising β‐carotene (9 mg/day), vitamin C (1500 mg/day), vitamin E (130 mg/day), zinc (45 mg/day), selenium (76 μg/day) and garlic (150 mg/day) or a placebo (n=18) for 4 weeks. Anti‐oxidant capacity (AC), serum levels of vitamin C, vitamin E, β‐carotene and selenium, peripheral blood responses, exhaled nitric oxide (eNO), as a marker of airway inflammation, and plasma F2 isoprostanes, as a measure of oxidative stress, were measured before and after supplementation.Results
Anti‐oxidant supplementation resulted in significant increases in serum levels of vitamin C, vitamin E, β‐carotene and selenium levels, compared with the placebo group (P<0.001). There was no change in serum AC, plasma F2‐isoprostanes, eNO or immune responses following supplementation with anti‐oxidants compared with placebo.Conclusion
Supplementation with anti‐oxidants resulted in significantly increased levels of vitamin C, vitamin E, β‐carotene and selenium but no change in immune responses, serum AC or plasma F2‐isoprostanes.
Mechanism of a plastic phenotypic response: predator‐induced shell thickening in the intertidal gastropodLittorina obtusata
Authors: BROOKES J. I. , ROCHETTE RÉMY 
Published: January 2007

AbstractPhenotypic plasticity has been the object of considerable interest over the past several decades, but in few cases are mechanisms underlying plastic responses well understood. For example, it is unclear whether predator‐induced changes in gastropod shell morphology represent an active physiological response or a by‐product of reduced feeding. We address this question by manipulating feeding and growth of intertidal snails,Littorina obtusata, using two approaches: (i) exposure to predation cues from green crabsCarcinus maenasand (ii) reduced food availability, and quantifying growth in shell length, shell mass, and body mass, as well as production of faecal material and shell micro‐structural characteristics (mineralogy and organic fraction) after 96 days. We demonstrate thatL. obtusataactively increases calcification rate in response to predation threat, and that this response entails energetic and developmental costs. That this induced response is not strictly tied to the animal's behaviour should enhance its evolutionary potential.