In previous studies place fields have been shown to be governed by one or more polarizing stimuli such that rotation of the stimuli caused concomitant rotation of the fields. Place fields have also been observed to persist after removal of stimulus cues. In the present study we confirm the previous ...

Some species of fish are able to discriminate, in addition to intensity and wavelength (color), the direction of polarization of visible light. Optical experiments on axially oriented retinal cones from trout and sunfish with use of two types of polarization microscope indicate anisotropic light transmission through paired cones. The measured ...

We report a new type of illusory contour (Illusory-O) whose formation is contingent upon the contrast polarity of its juxtaposed inducing elements being similar, i.e. both elements must either be positive or negative in contrast sign. To test the hypothesis that this contingency is primarily dictated by factors that determine ...

We report on the development of a method that records spatially dependent intensity patterns of polarized light that is diffusely backscattered from highly scattering media. It is demonstrated that these intensity patterns can be used to differentiate turbid media, such as polystyrene-sphere and biological-cell suspensions. Our technique employs polarized light ...

BACKGROUND: Polarized light photography has been used to selectively differentiate surface from subsurface features of photoaged skin. OBJECTIVE: Our purpose was to compare acne assessments obtained from clinical evaluations with assessments from photographs obtained with flash photography and with perpendicular polarized light photography. METHODS: Assessments of acne with the Cunliffe ...

The present investigation is aimed at characterizing the development of ON and OFF visually evoked responses in the rat superior colliculus from postnatal day 13 (P13) to postnatal day 25. Depth profiles of field potentials reveal that ON and OFF long latency biphasic field potentials are already present when collicular ...

Experiments are presented showing that under dual-frequency, orthogonal-polarization pumping, stimulated Raman scattering in optical birefringent fibers can be suppressed in one of the two fiber axes. For relatively small-frequency spacing and group-velocity mismatch between the pumps, Stokes light is suppressed along the polarization direction of the highest-frequency pump, owing to ...

In the waveguiding limit, a twisted nematic liquid crystal cell behaves as an achromatic polarization rotator. We propose and demonstrate the application of such a polarization rotator to convert unpolarized light into linearly polarized light with almost 100% efficiency. This polarization converter has a 2:1 aspect ratio, which is close ...

The absolute coagulation rate constants of monodisperse spherical colloids in aqueous suspension were measured at the early stage of the coagulation processes by using two different techniques: single particle light scattering (SPLS) and simultaneous static and dynamic light scattering (SLS + DLS). Single particle light scattering determines the cluster-size distribution ...

The formation of shear induced structures (SIS) of a mixed micellar solution of tetradecyldimethylaminoxide and sodium dodecylsulfate is studied by light scattering experiments under shear (rheo-optical method). In the shear rate- as well as in the time-dependent measurements we found an aggregation process taking part in the SIS formation. Below ...

A novel, non-modulated polarimeter called a polarized photometric detector (PPD) was previously described by the authors. The PPD enables the measurement of the optical rotation of chiral compounds as a change in absorbance by placing two linear polarizers on either side of a flow cell of a conventional photometric detector. ...

We measured the spectral distributions of the underwater total and polarized light fields in the upper photic zone of meso-eutrophic waters (i.e., blue-green waters containing medium to high chlorophyll a concentrations). Per cent polarization levels during the day were always lower than 40%, but at crepuscular times these values could ...

Preattentive grouping is supported by 2 systems, a brightness system that is contrast polarity sensitive and an edge system that is relatively insensitive to contrast polarity. Search was spatially parallel for pairs of same contrast polarity vertically aligned circles, among horizontal pairs, and serial for pairs of circles that had ...

The sensitivities of two species of sunfish (Lepomis gibbosus and Lepomis cyanellus) to the electric field (E-vector) of polarized light were assessed by compound action potential recordings from the optic nerve of live fish. Under white light and long wavelength adapting backgrounds, two cone mechanisms were found with maximum sensitivities ...

This article introduces an experimental paradigm to selectively probe the multiple levels of visual processing that influence the formation of object contours, perceptual boundaries, and illusory contours. The experiments test the assumption that, to integrate contour information across space and contrast sign, a spatially short-range filtering process that is sensitive ...

The effect of stimulus size on the pattern onset-offset visual evoked potential elicited with stimuli of two different wavelengths is studied under intensive yellow adaptation: (1) The onset response obtained with a 460 nm pattern is of negative polarity (N1) and saturates in amplitude with a stimulus radius of 7 ...

Laser light scattering comes in two major 'flavors': dynamic and static. This noninvasive technique provides a means for investigating key size and shape properties of macromolecules in solution. Light scattering has long been an indispensable tool to the polymer physical chemist, and is seeing increased use in exploring properties of ...

A study designed to determine how inducer-surround contrast and inducer polarity affect the contour clarity and the lightness of illusory figures is reported. Using magnitude estimation procedures, ten naive subjects rated both the contour clarity and the lightness of Kanizsa squares. The magnitude of the inducer-surround contrast and the inducer ...

Clock-shifting (altering the phase of the internal clock) in homing pigeons leads to a deflection in the vanishing bearing of the clock-shifted group relative to controls. However, two unexplained phenomena are common in clock-shift experiments: the vanishing bearings of the clock-shifted group are often more scattered (with a shorter vector ...

We have observed that a light beam that passed through an optically active crystal of Bi(12)SiO(20) and that was then ref lected exactly back through it did not recover its initial polarization orientation. The nonreciprocal component of the rotation was of the order of 2 x 10(-3) of the reciprocal, ...

The factors potentially determining the dynamics of horizontal cell (HC) responses are: (1) the rate of transmitter release (including its transient component) and removal; (2) the voltage non-linearity of HC non-synaptic membrane combined with its capacitance; and (3) the dynamics of feedback from HCs to photoreceptors. Using, in consecutive order, ...

Spectral analysis of a time-evolving speckle pattern is used to provide motion-resolved detection of moving objects embedded within scattering media. Results show that the ability to detect small nonstationary scattering objects and to discriminate between objects moving at different rates is greatly enhanced.

The refractive index and the thickness of a transparent pellicle are determined when the pellicle is placed between two vertical crossed polarizers and rotated in the horizontal plane. The transmission axes of the polarizers are neither parallel nor perpendicular to the plane of incidence. The light transmitted through the crossed ...

The aim of the present study was to examine whether euclidean structure could be recovered from apparent motion sequences under polar projection. In Experiment 1, length judgments of two sides of a simulated triangle rotating in depth did not reveal effects of type of projection, polar or parallel, on the ...

Polarization characterization of a Mach-Zehnder interferometer, based on the state of polarization (SOP) and power measurement at the interferometer output, is presented. We study the SOP and degree of polarization (DOP) of the output light, first as a function of the light power in each arm of the interferometer for ...

The auditory brain-stem responses (ABRs) to rarefaction and condensation clicks were obtained for 12 normal-hearing subjects in quiet, and high-pass masking at 8, 4, 2, 1, and 0.5 kHz. Derived narrow-band wave V latency differences were analyzed with respect to (1) stimulus polarity, (2) absolute differences irrespective of polarity. The ...

The effect of molecular motion on the heteronuclear cross-polarization rate for the case of the spin-lock procedure was investigated. In applying heteronuclear solid state NMR techniques to mobile elastomer systems the influence of molecular motion cannot be neglected. Starting in the slow motion regime a strong collision model was used ...

While the ability to analyze polarized light is widespread among animals, its contribution to form vision has not yet been documented. We tested the hypothesis that polarization vision can be used for object discrimination, by training octopuses to distinguish between targets on the basis of the presence or absence of ...

A mode of operation is introduced for the standard 90° twisted nematic (TN) liquid-crystal cell when placed together with an interference filter and positioned between crossed polarizers such that a small stimulating voltage of between ±2.0 and ±13.0 V is required in order to attain the light state. Further incrementation ...

Vernier acuity for opposite-contrast polarity stimuli clearly poses problems for local contrast models of relative position processing. In Expt 1 we show that vernier thresholds for abutting, or closely separated features of opposite-contrast polarity, are degraded across a wide range of stimulus strengths and configurations; but for widely separated stimuli ...

A new, long-path integrated optical (IO) sensor for the detection of non-polar organic substances is described. The sensing layer deposited on a planar multimode IO structure is built by a suitable silicone polymer with lower refractive index (RI). It acts as a hydrophobic matrix for the reversible enrichment of non-polar ...

Human observers were trained to criterion in classifying compound Gabor signals with symmetry relationships, and were then tested with each of 18 blob-only versions of the learning set. Generalization to dark-only and light-only blob versions of the learning signals, as well as to dark-and-light blob versions was found to be ...

"Recently, the concept of differential urbanization was introduced. It conceptually links the processes of urbanization, polarization reversal, and counterurbanization across the development spectrum in the First and Third Worlds. Based on supporting evidence in developed and less developed countries, this study expands the theoretical foundation of the concept by first ...

The ability to move is one of the most basic and critical functions of the neutrophil. The neutrophil changes its shape from round to highly polar and glides along the surface, pausing every 45 to 60 seconds to reestablish its direction. Iterations of this sequence of small-scale motion, or shape ...

Ceratodon protoplasts regenerate by polar outgrowth to form cell filaments. The kinetics of regeneration show that some cellular event has to be completed before regeneration can be initiated. The development of the regeneration axis is strongly influenced by light, with axis alignment and axis polarity being fixed independently. We define ...

The reflectance of an absorbing medium for incident light of arbitrary polarization can exhibit two extrema at angles of incidence φ(max) and φ(min). The behavior of iso-φ(max) and iso-φ(min) contours in the complex plane of a dielectric constant for various incident polarizations is analyzed.

Microtubules nucleated by sea urchin sperm-tail axonemes have polar ends that differ both functionally and structurally but cannot be distinguished from one another when viewed by light microscopy. Ambiguity and circularity surround any classification of microtubule polarity by conventional methods. Chlamydomonas flagellar axonemal pieces have distinct morphological differences at their ...

BACKGROUND: The clinical characteristics of photodamaged skin, such as coarse and fine wrinkling, sallowness, hyperpigmentation, tactile roughness, laxity, and erythema, are not accurately evaluable from photographic records. OBJECTIVE: The purpose of this study was to develop accurate and reproducible photographic techniques that generate an evaluable record of the characteristics of ...

The study measured the shift in apparent position of a color-defined target boundary as a function of the distance, luminance polarity and amount of contrast of a nearby luminance-defined flanking boundary. In general, the position of the target boundary shifted towards the flank with the attraction being somewhat greater for ...

The electric parameters of Na+/K(+)-ATPase labeled by FITC have been characterized by measurements of the fluorescence-detected electric dichroism. The fluorescence emission was measured with polarizers at the magic angle and the light for excitation was usually polarized parallel to the field vector. The FITC-Na+/K(+)-ATPase preparations exhibit a negative electric dichroism ...

Light scattered from optically active spheres was theoretically analyzed for biodetection. The circularly polarized signal of near-forward scattering from circularly dichroic spheres was calculated. Both remote and point biodetection were considered. The analysis included the effect of a circular aperture and beam block at the detector. If the incident light ...

Electric signals associated with the photocycle of bacteriorhodopsin carry valuable information about the proton transport process. Photocurrents measured by different experimental methods are interpreted in terms of intramolecular charge displacements. Permanent electrical asymmetry of the sample is considered to be a prerequisite for the detection of electric signals. The various ...

Paleomagnetic data from the Mid-Cretaceous Mountains suggest that Pacific plate motion during the Early to mid-Cretaceous was slow, less than 0.3 degree per year, resembling the polar standstill observed in coeval rocks of Eurasia and North America. There is little evidence for a change in plate motion that could have ...

Under a ramp-and-hold stretch the Ia afferent responds to the beginning of the ramp phase with an initial frequency peak, which is followed during the ongoing dynamic phase of stretching by further frequency peaks. In this investigation the behavior of the initial peak is compared with the behavior of the ...

We realized hologram storage within a 0.07-cm(2) light spot in thin layers of polyvinyl alcohol matrices doped with Methyl Orange dyes preirradiated by the 488.0-nm line of an Ar-ion laser with two orthogonal linearly polarized 632.8-nm light beams. By rotation of the sample, multiple-hologram storage was achieved. By controlling the ...

This study was conducted to investigate morphologic differences in the ABR as a result of reversing the stimulus polarity of frequency-limited single-cycle stimuli in normal-hearing subjects. The results clearly demonstrate that large latency differences occur between condensation and rarefaction stimuli for low-frequency stimuli. It is believed that polarity-specific latencies are ...

The detectability of silica particles in ordinary histologic sections by means of polarizing light microscopy has been controversial. Through the application of both correlative light microscopy and scanning electron microscopy to different lung sections, we showed that particles demonstrating peaks for silicon only by energy-dispersive x-ray microanalysis were in fact ...

Visual evoked potentials (VEPs) to pattern reversal vertical bar stimuli were recorded from 19 scalp, 2 zygomatic and 3 inion derivations referenced to digitally linked earlobes in 50 controls. 1, 2 and 4 cycles per degree (cpd) patterns were presented as full field (FF) stimuli, on upper and lower hemifields ...

A new parameter called the coefficient of reflectivity differentiated with respect to the wavelength of light (dR/dλ) is introduced. This parameter is used to describe a new method of determining the optical properties, a refractive index, and the thickness of nonabsorbent thin films from reflectivity R and a differential coefficient ...

Mueller-matrix polarimetry performed in the visible and near IR indicates that an integrating sphere acts as an ideal depolarizer to the 0.5% accuracy of the polarimeter. The integrating sphere emits unpolarized light regardless of the incident polarization state.