bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐lasting effects of elevated neonatal leptin on rat hippocampal function, synaptic proteins and NMDA receptor subunits
Authors: Walker Claire‐Dominique , Long Hong , Williams Sylvain , Richard Denis
Published: January 2007

The high circulating levels of leptin in neonatal rodents do not seem to be regulating energy balance at this age, but rather may play an important role for brain development. We tested the hypothesis that high neonatal leptin levels modify hippocampal function and production of synaptic proteins with possible long‐term consequences on long‐term potentiation (LTP) in adulthood. We first showed that in postnatal day (PND) 10 neonates, acute leptin treatment functionally activated leptin receptors (ObR) in the CA1 and DG regions of the hippocampus through the induction of phosphoERK1/2, but not phosphoSTAT3 protein although both phospho‐proteins were induced in the arcuate nucleus. We next examined whether chronic leptin administration (3 mg/kg BW, intraperitoneally) during the first 2 weeks of life (postnatal day, PND 2–14) produces a functional signal in the hippocampus that alters the expression of NMDA receptor subunits (NR1, NR2A, NR2B), synaptic proteins and LTP in the short and long‐term. In PND 10 as in adults (PND 70) rats, chronic leptin treatment increased NR1 expression in the hippocampus while reducing NR2B protein levels. Elevated hippocampal concentrations of synapsin2A and synaptophysin were detected during leptin treatment on PND 10 suggesting increased neurotransmitter release. In adults, only SNAP‐25 expression was increased after neonatal leptin treatment. LTP was reduced dramatically by leptin treatment in preweaning rats although the changes did not persist until adulthood. Elevated exposure to leptin during a critical period of neonatal hippocampal development might serve to enhance NMDA‐dependent functions other than LTP and have important effects on synaptogenesis and neurotransmitter release. © 2007 Wiley‐Liss, Inc.
Functional Polymer‐Bioconjugates as Molecular LEGO® Bricks
Authors: Börner Hans G.
Published: January 2007

The controlled integration of sequence‐defined oligopeptides into synthetic polymers leads to peptide‐polymer conjugates with precisely defined, multifunctional peptide segments. These bioconjugates allow for the direct realization of bio‐inspired polymer science. Peptides combine self‐assembly properties with the potential to actively interact with biological systems. Hence conjugates can be exploited to program microstructure formation processes in polymeric materials by controlling secondary interactions between the peptide segments. Moreover, the programmable functionalities of the peptides can be used to tune specific interactions, e.g., between drugs and polymeric drug carriers or between inorganic crystal surfaces and polymeric crystal‐growth modifiers.

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Exact expected values of variance estimators for simulation
Authors: Aktaran‐Kalaycı Tûba , Alexopoulos Christos , Argon Nilay Tanık , Goldsman David , Wilson James R.
Published: January 2007

We formulate exact expressions for the expected values of selected estimators of the variance parameter (that is, the sum of covariances at all lags) of a steady‐state simulation output process. Given in terms of the autocovariance function of the process, these expressions are derived for variance estimators based on the simulation analysis methods of nonoverlapping batch means, overlapping batch means, and standardized time series. Comparing estimator performance in a first‐order autoregressive process and the M/M/1 queue‐waiting‐time process, we find that certain standardized time series estimators outperform their competitors as the sample size becomes large. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Working with Arab American families: Culturally competent practice for school psychologists
Authors: Haboush Karen L.
Published: January 2007

Individuals of Arab descent residing within the United States currently number between 1.2 million and 3.9 million. These families are characterized by considerable diversity depending upon their nationality, religion, and extent of acculturation to both Western and Arab cultures. More recently, Arab families have immigrated to the United States in response to traumatic events, such as war, a situation that has complicated their subsequent adjustment and acculturation to life in the United States. The growth in the Arab American population suggests that school psychologists are increasingly likely to work with their children and families. However, despite the National Association of School Psychologists (NASP; 2000) and American Psychological Association (APA; 2002) ethical guidelines requiring culturally competent practice, little has been written to guide the school psychologist's work with this population. This article draws on the available literature on Arab cultural values and acculturation to enhance culturally sensitive school psychology practice at the individual and systems levels. © 2007 Wiley Periodicals, Inc. Psychol Schs 44: 183–198, 2007.
Learning from examples in unstructured, outdoor environments
Authors: Sun J. , Mehta T. , Wooden D. , Powers M. , Rehg J. , Balch T. , Egerstedt M.
Published: January 2007

In this paper, we present a multi‐pronged approach to the “Learning from Example” problem. In particular, we present a framework for integrating learning into a standard, hybrid navigation strategy, composed of both plan‐based and reactive controllers. Based on the classification of colors and textures as either good or bad, a global map is populated with estimates of preferability in conjunction with the standard obstacle information. Moreover, individual feedback mappings from learned features to learned control actions are introduced as additional behaviors in the behavioral suite. A number of real‐world experiments are discussed that illustrate the viability of the proposed method. © 2007 Wiley Periodicals, Inc.
Towards learned traversability for robot navigation: From underfoot to the far field
Authors: Howard Andrew , Turmon Michael , Matthies Larry , Tang Benyang , Angelova Anelia , Mjolsness Eric
Published: January 2007

Autonomous off‐road navigation of robotic ground vehicles has important applications on Earth and in space exploration. Progress in this domain has been retarded by the limited lookahead range of three‐dimensional (3D) sensors and by the difficulty of heuristically programming systems to understand the traversability of the wide variety of terrain they can encounter. Enabling robots to learn from experience may alleviate both of these problems. We define two paradigms for this, learning from 3D geometry and learning from proprioception, and describe initial instantiations of them as developed under DARPA and NASA programs. Field test results show promise for learning traversability of vegetated terrain and learning to extend the lookahead range of the vision system. © 2007 Wiley Periodicals, Inc.
Photon‐induced field desorption of NO from Rh
Authors: Drachsel W. , Teutsch Th.
Published: January 2007

The effect of an electric field on the NO photo‐desorption from Rh was investigated using a pulsed laser atom probe. Experiments were carried out at 78 K by irradiating a [111] oriented Rh field‐emitter tip and a Rh single crystal of 1.4 mm diameter at 6.4 eV and at 3.2 eV photon energy. The energies and masses of the emitted ions were evaluated from time‐of‐flight (ToF) measurements. For 6.4 eV irradiation of the Rh tip, a quadratic yield dependence on the laser fluence has been observed for NO. This is interpreted as a two‐photon ionization of field‐adsorbed NO; this is supported by the same behavior of O2 and Xe but at a comparatively lower yield. In cases where the ionization energy of the probed species (Ar, N2, CO) is higher than 12.8 eV no such effect is observed. Laser irradiation with 2.3 eV photons initiates thermally assisted field desorption of the species at a comparatively higher fluence. Ion energy analysis suggests re‐neutralization of NO+ in the forbidden zone, but the translational energy gained appears to be sufficient to overcome the desorption barrier and field ionizion at the critical distance becomes probable. At low laser fluence a weak linear photo‐desorption process has been detected, presumably caused by substrate‐mediated electronic excitation as a first step. In this model, the photo‐desorbed NO will subsequently be field‐ionized, and accelerated away by the field. For the Rh single crystal, NO photo‐desorption, with two‐photon ionization in a second step, is deduced as the most probable mechanism. Copyright © 2007 John Wiley & Sons, Ltd.
Field ion microscopy and beyond in some aspects of surface and nanoscience applications
Authors: Tsong Tien T.
Published: January 2007

Two of the most important aspects of atomic resolution microscopy are the atomic resolution imaging of the sample and the nondestructive chemical analysis of preselected sample atoms. Field ion microscopy (FIM) is the first microscopy to achieve atomic image resolution, whereas the atom‐probe FIM is the first one to achieve single‐atom chemical analysis of preselected sample atoms, though, unfortunately, it is destructive. As microscopy progresses, now both electron microscope and scanning probe microscope have achieved atomic image resolution. STM may one day be able to do nondestructive chemical analysis of single sample atoms using thermally stable and chemically inert single‐atom sharp tip for the measurement of the electronic density of states of these atoms. Here, I will discuss a principle of STM chemical analysis as well as how field ion microscopy studies have instigated some of the later studies of scanning tunneling microscopy in surface and nanoscience applications. Copyright © 2007 John Wiley & Sons, Ltd.
Diamond and boron carbide field emission in medium vacuum
Authors: Melmed Allan J.
Published: January 2007

Field electron emission current–time and current–voltage measurements were made on single field emitters of synthetic diamond and boron carbide in medium vacuum (10−5–10−8 Torr), and two diamond specimens were characterized by scanning electron microscopy (SEM) and field ion microscopy (FIM). Generally, we found that the boron carbide emitters were less noisy than the diamond emitters, and that emission current stability improved with increasing current, at least up to 6 × 10−6 A. Use of the conventional field electron microscope (FEM) configuration enabled direct visualization of the surface condition during emission current and voltage measurements, and the combination of FIM and FEM permitted an estimation of current density for one diamond specimen, 1 × 106 A/cm2. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization of precipitates in aluminium‐based alloy AW 6016
Authors: Wanderka N. , Schiffmann R. , Banhart J.
Published: January 2007

The aluminium‐based engineering alloy AW 6016 of nominal composition 98.44 Al–0.45 Mg–0.96 Si–0.11 Fe–0.034 Mn–0.0054 Zn–0.0038 Cr was investigated (all values are given in at.%). Heat treatment of solutionized and quenched alloys leads to an increase in hardness, which is due to the formation of small precipitates of nanometer scale size. Two complementary high‐resolution methods, namely transmission electron microscopy (TEM) and three‐dimensional atom probe (3‐DAP), are used for investigations of the precipitate evolution after annealing at 185 °C and 235 °C. At very early stages, i.e. after 5 min at 185 °C, Mg‐rich, Si‐rich and MgSi co‐clusters are observed. They are spherical and their diameter is between 1 and 3 nm. The number density of clusters as measured by 3‐DAP is 9 × 1023/m3. After ageing for 25 min and 90 min at 185 °C, GP zones and a needle‐like β″ phase are formed. Both are rich in Mg and Si. The concentration ratio of Mg to Si of the precipitates is ∼1. The number density of all precipitates after 90 min annealing time at 185 °C is 6 × 1023/m3. The needle‐like β″ precipitates at this ageing stage are about 4 nm in diameter and longer than 10 nm.

The precipitates formed at 235 °C after 10 min are much larger when compared to those formed at 185 °C. They are rod‐shaped and have an average size as measured by TEM, about 50 nm in length and 3–4 nm in cross section. The concentration ratio between Mg and Si as measured by 3‐DAP is about 1. Copyright © 2007 John Wiley & Sons, Ltd.
Grain‐boundary segregation in nanocrystalline CuBi layers studied with the tomographic atom probe
Authors: Wolde‐Giorgis Daniel , Al‐Kassab Tala'at , Kirchheim Reiner
Published: January 2007

In an effort to prepare nanocrystalline Bi‐doped Cu layers, the Ar sputter deposition technique was applied. In previous works, polycrystalline grain growth on planar substrates was reported. On the apex of W tips with a radius of curvature of about 20–35 nm, we find columnar nanocrystalline grain growth. The Cu bilayers so prepared were characterized by means of the atom probe tomography (APT) and field ion microscopy (FIM). Lamellar structures of grain boundaries and isolated grain boundaries are observed. Without any post‐annealing after deposition, we find elevated concentrations of Bi at discrete grain boundaries and in the grains. Copyright © 2007 John Wiley & Sons, Ltd.
Knockout of frataxin gene causes embryo lethality in Arabidopsis
Authors: Vazzola Valentina , Losa Alessia , Soave Carlo , Murgia Irene
Published: January 2007

The frataxin homolog from Arabidopsis thaliana (AtFH) is a single nuclear‐encoded gene targeted to mitochondria and sharing 65% similarity with animal frataxin. In the present work, we show that the knocking out of AtFH gene causes arrest of Arabidopsis embryo development at the globular stage. Consistently with that, we also show by in situ hybridization that AtFH is expressed, in wt Arabidopsis plants, in ovule primordia as well as in embryos at various stages of development, suggesting a key role of plant frataxin during embryogenesis.
Genetic correlations between temperament and breeding traits in Limousin heifers
Authors: Phocas F. , Boivin X. , Sapa J. , Trillat G. , Boissy A. , Le Neindre P.
Published: January 2007

The aim of this study was to assess the potential consequences of selection for less aggressive or active animals during handling by estimating genetic correlations between different criteria of temperament and Limousin heifer breeding traits. Data consisted of the records collected from 1992 to 2004 at the progeny test station of Limousin AI sires. Six traits recorded during the same behavioural test – the so-called docility test – were considered to describe the heifer's temperament: aggressiveness against the handler, running time and number of escapes per minute of test period in presence or absence of the handler and a synthetic docility score accounting for the five previous components. Eight breeding traits were also considered simultaneously in the joint analysis with the five elementary temperament components: weights at 12 months and after calving (for measuring heifer growth), age at first observed oestrus (for measuring puberty) and fertility (for measuring heifer reproductive performance), calving ease score and pelvic opening (for measuring calving performance), maternal behaviour at calf's birth and milk yield (for measuring the suckling ability of the primiparous cow). REML (co)variance estimates were derived using linear multitrait sire models. Estimates of heritability were in the range of values given in the literature. Estimates of genetic correlation between temperament traits indicated that, genetically, aggressive animals also attempt to escape a lot. Consequently, their elimination will reduce both working risk and handling time for the breeder. Genetic correlations between temperament traits and breeding traits ranged from zero to favourable estimates and confirmed the very few results of the literature indicating a slight trend of less fearful heifers also being more productive, mainly because of a higher reproduction and calving performance, and, to a lesser extent, because of higher maternal abilities such as behaviour at calf's birth and milk yield.
Satellite chartography of atmospheric methane from SCIAMACHY on board ENVISAT: 2. Evaluation based on inverse model simulations
Authors: Bergamaschi P. , Frankenberg C. , Meirink J. F. , Krol M. , Dentener F. , Wagner T. , Platt U. , Kaplan J. O. , Körner S. , Heimann M. , Dlugokencky E. J. , Goede A.
Published: January 2007

We extend the analysis of a global CH4 data set retrieved from SCIAMACHY (Frankenberg et al., 2006) by making a detailed comparison with inverse TM5 model simulations for 2003 that are optimized versus high accuracy CH4 surface measurements from the NOAA ESRL network. The comparison of column averaged mixing ratios over remote continental and oceanic regions shows that major features of the atmospheric CH4 distribution are consistent between SCIAMACHY observations and model simulations. However, the analysis suggests that SCIAMACHY CH4 retrievals may have some bias that depends on latitude and season (up to ∼30 ppb). Large enhancements of column averaged CH4 mixing ratios (∼50–100 ppb) are observed and modeled over India, Southeast Asia, and the tropical regions of South America, and Africa. We present a detailed comparison of observed spatial patterns and their seasonal evolution with TM5 1° × 1° zoom simulations over these regions. Application of a new wetland inventory leads to a significant improvement in the agreement between SCIAMACHY retrievals and model simulations over the Amazon basin during the first half of the year. Furthermore, we present an initial coupled inversion that simultaneously uses the surface and satellite observations and that allows the inverse system to compensate for the potential systematic bias. The results suggest significantly greater tropical emissions compared to either the a priori estimates or the inversion based on the surface measurements only. Emissions from rice paddies in India and Southeast Asia are relatively well constrained by the SCIAMACHY data and are slightly reduced by the inversion.
Use of ISLSCP II data to intercompare and validate the terrestrial net primary production in a land surface model coupled to a general circulation model
Authors: Dan Li , Ji Jinjun , He Yong
Published: January 2007

Using the global terrestrial NPP and climate data from International Satellite Land Surface Climatology Project Initiative II (ISLSCP II) and additional NPP data, we validated the NPP simulations and explored the relationship between NPP and climate variation in a global two‐way coupled model AVIM‐GOALS. The strength of this study is that the global simulations produced will enhance interactive climate and vegetation study; however, the weakness is that the NPP distribution is not fully reproduced in some regions, because of the coarse model resolution and climate biases. Global NPP is spatially consistent with IGBP NPP and MODIS data, though there is a discrepancy in NPP (significantly lower values) for boreal forests and tundra, due to the underestimated temperature. The NPP distribution in China indicates agreement with IGBP data, but the IGBP data in northeast China (around 48°N) seem to be slightly high in contrast with other modeled and estimated NPP. The spatial structure of NPP in USA and Australia roughly corresponds to the IGBP NPP data and GPPDI Gridded data, and a possible lower value of GPPDI data in central Australia exists, in contrast with other NPP data. The globally averaged NPP of 447.47 g C m−2 year−1 is close to the 450.42 g C m−2 year−1 from IGBP data. The global relative error of simulated NPP against IGBP data is about 20% and is comparable to other global biogeochemical models. The meridional variation of globally zonal mean NPP corresponds more to the meridional change of precipitation than temperature. The global NPP for all vegetation types is highly statistically significant in correlation with precipitation.
Nanoparticles: pharmacological and toxicological significance
Authors: Medina C , Santos‐Martinez M J , Radomski A , Corrigan O I , Radomski M W
Published: January 2007

Nanoparticles are tiny materials (<1000 nm in size) that have specific physicochemical properties different to bulk materials of the same composition and such properties make them very attractive for commercial and medical development. However, nanoparticles can act on living cells at the nanolevel resulting not only in biologically desirable, but also in undesirable effects. In contrast to many efforts aimed at exploiting desirable properties of nanoparticles for medicine, there are limited attempts to evaluate potentially undesirable effects of these particles when administered intentionally for medical purposes. Therefore, there is a pressing need for careful consideration of benefits and side effects of the use of nanoparticles in medicine. This review article aims at providing a balanced update of these exciting pharmacological and potentially toxicological developments. The classes of nanoparticles, the current status of nanoparticle use in pharmacology and therapeutics, the demonstrated and potential toxicity of nanoparticles will be discussed.

British Journal of Pharmacology (2007) 150, 552–558. doi:10.1038/sj.bjp.0707130
Terahertz imaging diagnostics of cancer tissues with a chemometrics technique
Authors: Nakajima Sachiko , Hoshina Hiromichi , Yamashita Masatsugu , Otani Chiko , Miyoshi Norio
Published: January 2007

Terahertz spectroscopic images of paraffin-embedded cancer tissues have been measured by a terahertz time domain spectrometer. For the systematic identification of cancer tumors, the principal component analysis and the clustering analysis were applied. In three of the four samples, the cancer tissue was recognized as an aggregate of the data points in the principal component plots. By the agglomerative hierarchical clustering, the data points were well categorized into cancer and the other tissues. This method can be also applied to various kinds of automatic discrimination of plural components by terahertz spectroscopic imaging.
Diameter dependent transport properties of gallium nitride nanowire field effect transistors
Authors: Motayed Abhishek , Vaudin Mark , Davydov Albert V. , Melngailis John , He Maoqi , Mohammad S. N.
Published: January 2007

The authors report transport property measurements of individual GaN nanowire field effect transistors and the correlation of the electron mobilities with the existence of grain boundaries in these nanowires. Room temperature field effect electron mobilities as high as 319cm2V−1s−1 were obtained for the 200nm diameter nanowires. Mobilities calculated from these reliable nanowire field effect transistors indicated that the surface scattering plays a dominant role in smaller diameter nanowires, whereas for intermediate diameter devices transport is dominated by grain boundary scattering. Reduction of the mobility with decreasing diameter of nanowires can be explained using “continuous surface” model.
Neurological Findings Associated with Spatial Disorders in Children
Authors: Salzarulo P , Bergès J , Pêcheux Marie-Germaine , Bounes Marika
Published: January 2007

Spatial disabilities are usually considered either from a cognitivist point of view or as a sign of ‘minimal brain damage’. We have studied disabilities associated with spatial orientation in 60 children, aged 8 to 10, referred to us for learning disabilities. Performances on the Bender Gestalt test and on the Bergès–Lézine test for the imitation of gestures have been related to the presence or absence of neurological soft signs, psychomotor disturbances, a pathological or mixed laterality, and a pathological anamnesis: the relationships among all these factors appear to be quite complex.

Difficulties in orienting arms in reference to the body may be related to neurological signs corresponding to a hypothetical brain damage. More complex imitations, involving subtle spatial relationships and reversibility, are impaired when psychomotor disturbances are present. Impairment of orientation in graphic space may result from an affective–emotional disorganisation, reflected by psychomotor troubles. All these results show how difficulties in imitating somebody else's movements and in reproducing a graphic model can be related to different kinds of neurological disorganisation, functional as well as organic.
Listening from Left to Right versus Right to Left
Authors: Bertelson P
Published: January 2007

Previous work has shown that the perceived temporal position of an extraneous signal in a spoken sentence can be influenced by the relative locations in auditory space of the apparent sources of the signal and of the speech. The relation is shown to depend on the direction of writing of the language used in the test.
The Interstimulus Interval for Taste: 2. Salt Taste Sensitivity Drifts and the Effects on Intensity Scaling and Threshold Measurement
Authors: O'Mahony M
Published: January 2007

The effects of demonstrated NaCl residuals from prior tastings were tested behaviourally by tasting successive ascending series of NaCl solutions, using three interstimulus procedures. Both inter- and intra-subject studies were performed. When concentrated NaCl solutions (10–1000 mM) were used the adaptation level was found to rise with successive tastings; mouthrinsing was a more effective method for preventing this rise than a 2 min or a 15 s rest. With low concentrations (distilled water–80 mM NaCl) the tendency for adaptation levels to rise, because of NaCl residuals, was smaller, while mouthrinsing made possible the detection of lower NaCl concentrations. The results are used to explain the variations, found in the literature, for NaCl threshold measurements and power function exponents for NaCl magnitude estimation studies.
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.
Perceptual Indices of Performance: The Measurement of ‘Inspection Time’ and ‘Noise’ in the Visual System
Authors: Vickers D , Nettelbeck T , Willson R J
Published: January 2007

Indices of human performance are less clear-cut than analogous measures in the physical sciences for several reasons. Variables which can alter performance include the noise upon which sensory signals are imposed, the bias shown by an observer towards one or another alternative, the use of an optional-stopping strategy for examining sensory input, and the accumulation of statistical information over time concerning the source of the input. The development of a theoretical appreciation of these variables is traced and, on this basis, a measure of the noise, which sets a limit to discriminative capacity, is suggested. The proposed index is simply the standard deviation of the best fitting normal ogive, calculated for the psychometric function obtained in a forced-choice discrimination task by the method of constant stimuli, the discriminanda being presented for 100 ms, in random order, and followed by appropriate backward masking. The index is thus closely related to traditional psychophysical measures, but is distinguished by the detailed specification of conditions under which it should be obtained. Analysis of data from previous experiments gives some indication of the order of magnitude that might be expected from a carefully controlled determination of the measure. In addition, three experiments were carried out to evaluate this suggestion, and to test its underlying rationale. In the first two, observers were required to discriminate, by pressing one of two keys, between two lines of markedly different length, exposed in random order for ten different durations. In the third, stimulus exposure was held constant, while ten different stimulus differences were presented in random order. Results from the first two experiments yielded estimates of minimum inspection time close to 100 ms, and were inconsistent with the view that observers can abandon an optional-stopping procedure of processing sensory information in favour of responding by a deadline. Measures of noise calculated in the third experiment were of the order expected on the proposed rationale, while response latencies were again inconsistent with the notion of deadline responding. Further analysis of the results of the three experiments suggests that measures of inspection time and noise, together with a third index related to the degree of caution exercised by an observer, appear to be stable and consistent descriptors of performance. The wider implications of the successful use of this kind of perceptual index of performance are discussed with reference to the measurement of visual acuity, as a means for detecting effects of environmental stress, and as a conceptual framework for the understanding of individual differences.
The Effects of Shock-Induced Anxiety on Noise in the Visual System
Authors: Nettelbeck T
Published: January 2007

Vickers et al. (1972) suggested that a useful index of noise in the visual system should be provided by a measure sD, defined as ‘the standard deviation of the best fitting normal ogive calculated for the psychometric function obtained in a forced-choice discrimination task using the method of constant stimuli, the discriminanda being presented for 100 ms, in random order, and followed by appropriate backward masking’. The sensitivity of sD to anxiety produced by painful electric shocks, arriving at unpredictable times, is examined. Results suggest that, although increased anxiety does not produce consistent or significant changes in heart rate or in degree of caution, it does cause a marked increase in noise.
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.
Studies on Induced Motion in the Third Dimension
Authors: Farnè M
Published: January 2007

Three experiments are described on induced motion in the third dimension. In experiment 1 two constant lines on a sheet of glass appear to move in depth as a consequence of the rapid displacements of a back surface (real inducing motion); this apparent motion is the more evident (i) the longer the inspection time and (ii) the faster the inducing stimulus. In experiment 2 a constant circle appears to move in depth as a consequence of the stroboscopic displacement of a surrounding circle (apparent inducing motion). Experiment 3 compares this last induced-motion effect with the aftereffect. The importance of a dynamic frame of reference is stressed.
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.
Directional Asymmetry in the Duration of Simple Movement Aftereffects Produced by Movement Aftereffects Contingent on Colour
Authors: Mayhew J E W
Published: January 2007

Movement aftereffects contingent on colour and pattern (CMAEs) were produced. A pattern, illuminated with red light and rotating clockwise, was alternated with its contrast-reversed ‘negative’, illuminated with green light and rotating counterclockwise. Subsequently, when the stationary patterns were presented, subjects reported counterclockwise MAEs on the ‘red’ pattern, and clockwise MAEs on the ‘green’ pattern. It was found that a simple MAE produced by adapting to the ‘red’ pattern and tested on the ‘green’ pattern was greater in duration when the direction of the inducing motion was opposite to that used in the CMAE adaptation procedure. It is suggested that this directional asymmetry in the duration of the simple MAE may be used as a within-subjects measure of the CMAE.
Salt Taste Sensitivity: A Signal Detection Approach
Authors: O'Mahony M
Published: January 2007

A flow procedure was used to measure the sensitivity of two subjects to NaCl stimuli after adaptation to 10 mM and 30 mM NaCl. The signal detection rating procedure was used and thirteen receiver operating characteristic (R.O.C.) curves obtained. Assumptions of normality and equal variance for the noise and signal plus noise distributions were upheld while d′ and nonparametric P( A) values were found to be comparable to those reported in earlier threshold studies. Advantages of the technique are discussed.
Relationships between Channels for Colour and Spatial Frequency in Human Vision
Authors: Virsu V , Haapasalo S
Published: January 2007

Five forms of relationships and four types of channels are possible between two systems of sensory channels. The relationships between channels for colour and spatial frequency were studied in three adaptation experiments. In the first, a new colour-specific spatial aftereffect was found, which indicates the existence of channels that are specific both to colour and to spatial frequency. The second showed that the spatial-frequency aftereffect of Blakemore and Sutton is not colour specific, which indicates that there are channels for spatial frequency that are not colour specific. The third demonstrated that coloured afterimages are not spatial-frequency specific immediately after adaptation, although they become so later. This indicates that there are channels for colour that are not spatial-frequency specific. The existence of these three types of channels implies that the channel systems for colour and spatial frequency overlap partially and mutually in the human visual system. This kind of organisation of channel systems, if it exists, may form the psychophysical structure that is required for the capacity of simultaneous integration and differentiation in the perception of colour and size of visual objects.
Monocular Movement Parallax and Near-Space Perception
Authors: Johansson G
Published: January 2007

Monocular perception of absolute distances in near space (<2 m) is discussed and studied experimentally. Stimulus change in time and sensory co-action (visual plus kinestethic) are in the theoretical analysis regarded as essential. Therefore movement parallax due to voluntary head movements has been introduced, in the experiments, as a hypothetical main cue, and perspective pattern transformation as a probably important side cue together with accommodation. (In ‘natural’ monocular perception these cues, in combination, are always available in near-space perception.) Under these experimental conditions all subjects exhibited approximately adequate (veridical) distance perception. This positive result, which diverges from the commonly accepted views about absolute-distance information, is tentatively regarded as an effect of the combination of cues and of methodological improvements introduced in the experiments. The result is taken as an indication of the fruitfulness of Gibson's conception of perceptual systems.
The Role of Eye Movements in the Perception of the Horizontal—Vertical Illusion
Authors: Schiffman H R , Thompson J
Published: January 2007

An experiment examining the role of eye movements in the determination of magnitude of the horizontal—vertical illusion (HVI) was performed by presenting the stimulus figures in conditions where eye movements or tendencies to eye movements were eliminated (i.e. presenting small figures tachistoscopically). The major result was that the illusion occurred within these conditions, indicating that eye movements do not play a major role in the production of the HVI. However, the finding that the magnitude of the HVI was positively affected in the conditions where tendencies to make eye movements were possible suggests that they exert a secondary role.
Species and Individuals in the Perceptual World of Monkeys
Authors: Humphrey N K
Published: January 2007

When a monkey is given the choice of looking at a novel picture or a blank white screen he shows an initial preference for the picture which usually abates within about 200 seconds; if the picture is then changed for another his preference revives. The level of preference for the second picture depends on the degree to which it is perceived as ‘similar’ to or ‘different’ from the first. This technique has been used to investigate how rhesus monkeys classify pictures of animals, and in particular the extent to which they differentiate between individual animals of the same species. Two classes of animal pictures were used, namely pictures of other rhesus monkeys and pictures of domestic animals. The results indicate that inexperienced monkeys, to whom the domestic animals are unfamiliar, treat individual domestic animals of the same species as being closely similar; they treat individual monkeys, on the other hand, as being quite different from each other. Experienced monkeys, however, who have been exposed over the course of 6 months to many further pictures of animals, come to treat all individuals as different from each other, so that one pig, say, is now seen as being as different from another pig as is one monkey from another.
The Distinction between the Rod-and-Frame Illusion and the Rod-and-Frame Test
Authors: Wenderoth P M
Published: January 2007

Errors in vertical settings of a test rod occur when the rod is enclosed in a laterally-tilted square-outline frame. The majority of previous experiments which have investigated this rod-and-frame effect have used a single frame tilt, usually 28°, and have tabulated errors as average unsigned deviations from gravitational vertical. Evidence is presented that, when the illusion is measured by taking algebraic differences between constant (signed) errors made with and without the frame being present, illusions occur in the direction of frame tilt for frame tilts up to about 25° from vertical (repulsion effects) but that directionally opposite illusions (attraction effects) occur for frame tilts between 25° and 45°. At the frame tilts used most frequently in previous studies (25° to 30°) little or no illusion occurs. A distinction is drawn between the rod-and-frame illusion (RFI), which has an angular function similar to the simple tilt illusion and aftereffect, and the rod-and-frame test (RFT), which uses unsigned deviations from vertical as its measure of error and which probably bears little or no relationship to the RFI.
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.
Profile Orientation and Social Distance in Portrait Painting
Authors: Coles P R
Published: January 2007

A study of portrait paintings by various artists revealed that the sitter's face is more likely to be illuminated by a light source to the artist's left than to his right. Although the sitter's face may be turned towards the artist's left or right side with equal frequency, the interaction of illumination and profile orientation does not appear to be arbitrary. This finding is interpreted in the context of other findings on left and right in picture perception, and a new explanation of the relationship between profile orientation and the personality of the sitter is offered.
Teaching African Children Pictorial Depth Perception: In Search of a Method
Authors: Deregowski J B
Published: January 2007

Data, suggesting that the exposure of pictorially relatively unsophisticated subjects to stereograms is likely to alleviate their difficulties in perception of pictorial depth in ordinary stimuli, are presented. It is suggested that this remedial measure may prove efficacious in populations that are experiencing such difficulties and are hence handicapped in their use of visual aids.
Beware of the Straight-Ahead Shift—A Nonperceptual Change in Experiments on Adaptation to Displaced Vision
Authors: Harris C S
Published: January 2007

Seen through sideways-displacing prisms, the wall of a room or testing apparatus looks displaced and slanted in depth. Consequently the viewer may involuntarily treat as straight ahead a a spatial direction that is displaced from his median plane toward the optically displaced, environmentally defined axes of space. There is evidence that such cognitive shifts in the subjective straight ahead do occur and are often larger than the adaptive shifts commonly found in experiments with prisms. A straight-ahead shift would affect performance on any task that involves judgments of the straight ahead, such as judging the visual straight ahead or pointing straight ahead with eyes closed. Thus a straight-ahead shift may give the misleading impression that there is a change in visual perception, or a ‘maladaptive’ change in position sense, when there actually is none (that is, no change in performance of any other visual or proprioceptive task). A straight-ahead shift could also produce a wide variety of other unexpected, paradoxical, or misleading findings like those that have been noted in previous experiments.
Recalibration by Pairing: A Process of Perceptual Learning
Authors: Epstein William
Published: January 2007

When two cues which normally agree in determining perceived depth are experimentally paired so that they designate discrepant values for the depth dimension, an opportunity is created for the recalibration or re-evaluation of the cues. Experiments which show recalibration of the oculomotor cues and recalibration of binocular disparity as a result of pairing these cues with other discrepant cues are reviewed. The locus of change is related to the relative dominance of different cues and the contribution of allocation of attention in determining dominance is discussed. Implications of recalibration by pairing for understanding ontogenetic development are considered. It is suggested that some cues may acquire their effectiveness as a consequence of pairing during development.
Depth Reduction Effects in Random-Line Stereograms
Authors: Frisby John P , Julesz Bela
Published: January 2007

The amount of depth seen in a random-line stereogram steadily diminishes as corresponding lines in the two fields of view are made increasingly dissimilar in shape. This depth reduction effect is more acute in high- than in low-density stereograms. Both of these results can be explained in terms of the magnetic dipole model of stereopsis.
Illusion-Destruction by Appropriate Scaling
Authors: Gregory Richard L , Harris John P
Published: January 2007

The inappropriate constancy scaling theory of visual distortion illusions is tested by optically projecting typical models giving these figures by perspective. Appropriate or inappropriate stereoscopic disparities are then added–with the prediction that when perspective and stereo are geometrically correct the distortion should vanish. This is confirmed with measurements for the Müller-Lyer illusion and by observation of several other classical examples. It is suggested that much previous work has investigated ‘end stop’ conditions, given by angles too extreme to be generated as perspective. Conditions for appropriate scaling, giving zero or small distortions, are found to be critical but readily attainable.