In the presence of certain symmetries, three-dimensional Dirac semimetals can harbor not only surface Fermi arcs, but also cones. Motivated by experimental observation rotation-symmetry-protected semimetal states in iron-based superconductors, we investigate potential intrinsic topological phases a $C_{4z}$-rotational invariant superconducting with $s_{\pm}$-wave pairing. When normal state harb...

PURPOSE To study the relationship between cone spacing and density and clinical measures of visual function near the fovea. METHODS High-resolution images of the photoreceptor mosaic were obtained with adaptive optics scanning laser ophthalmoscopy from 26 patients with inherited retinal degenerations. Cone spacing measures were made close to or at the foveal center (mean [SD] eccentricity, 0....

Deuteranomalous trichromacy, which affects medium-wavelength-sensitive cones, is more common than protanomalous trichromacy, which affects long-wavelength-sensitive cones. The aim of the present work was to test the extent to which these two kinds of anomalous trichromacy affect surface-color judgments in the natural world. Simulations of 18 natural scenes under different daylight illuminants w...

This study investigates the capacity of neuronal growth cones to synthesize protein locally and independently of their cell body. Isolated growth cones were prepared from cultures of neurons from the snail Helisoma by transecting neurites proximal to the growth cone. The capacity for protein synthesis was tested by radiolabeling cultures with 3H-leucine and analyzing the resultant autoradiogram...

Light enters the eye, is focused by the cornea, passes through the variable-diameter iris, is further focused by the lens, and strikes the light-sensitive receptors of the retina in the back of the eye. The photoreceptors of the retina can be divided into two basic categories: rods and cones. At normal light levels, cones dominate the initial response to light, resulting in photopic vision. Thr...

IMPORTANCE Stargardt disease (STGD1) is characterized by macular atrophy and flecks in the retinal pigment epithelium. The causative ABCA4 gene encodes a protein localizing to photoreceptor outer segments. The pathologic steps by which ABCA4 mutations lead to clinically detectable retinal pigment epithelium changes remain unclear. We investigated early STGD1 using adaptive optics scanning light...

Carriers of X-linked color vision deficiencies have previously been reported to exhibit mild abnormalities of color matching and discrimination. In a sample of 55 carriers of protan and deutan deficiencies and 55 age-matched normal controls, we measured chromatic discrimination along a red-green axis. We found that discrimination was impaired in the case of carriers of deutan deficiencies (whic...

There are three related concepts that arise in connection with the angular analysis of a convex cone: antipodality, criticality, and Nash equilibria. These concepts are geometric in nature but they can also be approached from the perspective of optimization theory. A detailed angular analysis of polyhedral convex cones has been carried out in a recent work of ours. This note focus on two import...

In the present report we used the calcium indicator fura-2 to compare intracellular levels of free calcium in growth cones of isolated Helisoma neurons under a variety of experimental conditions. We tested whether 2 different signals that inhibit growth cone motility--action potentials and serotonin--changed calcium levels in growth cones. Electrical stimulation of the cell body caused a rise i...