No local cancellation between directionally opposed first-order and second-order motion signals

AbstractDespite strong converging evidence that there are separate mechanisms for the processing of first-order and second-order motion, the issue remains controversial. Qian, Andersen and Adelson (J. Neurosci., 14 (1994), 7357–7366) have shown that first-order motion signals cancel if locally balanced. Here we show that this is also the case for second-order motion signals, but not for a mixture of first-order and second-order motion even when the visibility of the two types of stimulus is equated. Our motion sequence consisted of a dynamic binary noise carrier divided into horizontal strips of equal height, each of which was spatially modulated in either contrast or luminance by a 1.0 c/deg sinusoid. The modulation moved leftward or rightward (3.75 Hz) in alternate strips. The single-interval task was to identify the direction of motion of the central strip. Three conditions were tested: all second-order strips, all first-order strips, and spatially alternated first-order and second-order strips. In the first condition, a threshold strip height for the second-order strips was obtained at a contrast modulation depth of 100%. In the second condition, this height was used for the first-order strips, and a threshold was obtained in terms of luminance contrast. These two previously-obtained threshold values were used to equate visibility of the first-order and second-order components in the third condition. Direction identification, instead of being at threshold, was near-perfect for all observers. We argue that the first two conditions demonstrate local cancellation of motion signals, whereas in the third condition this does not occur. We attribute this non-cancellation to separate processing of first-order and second-order motion inputs

Scalable distributed resource location

Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 45).by Scott T. Smith.S.B.and M.Eng

Biological Effects of Corynebacterium Parvum. III. amplification of resistance and impairment of Active Immunity to Murine Tumours

The effect of pre-treatment with Corynebacterium parvum on the growth in vivo of a range of experimental mouse tumours with differing characteristics has been investigated. Varying degrees of protection were observed which were generally greater with the more immunogenic tumours. Administration of C. parvum 7 days before immunization with irradiated tumour cells diminished the protective effect which could be obtained by immunization alone. The possible basis for these seemingly conflicting influences is considered

Flourinated aryl ether polymers exhibiting dual fluoroolefin functionality and methods of forming same

Disclosed are telechelic fluoropolymers and methods for forming the polymers. The fluoropolymers can be formed via step-growth polymerization of bis(trifluorovinyloxy)biphenyls with bisphenols. The formed telechelic polymers possess fluoroolefin functionality at the trifluorovinyl aromatic ether endgroups. Internal groups can include difluorodioxyvinylene groups and trifluoroethyl groups. Formation methods of the telechelic polymers can be controlled so as to control molecular weight and degree of unsaturation of the polymers. The end groups and the internal groups can be further reacted independently of each other, e.g., under different temperature conditions, to form a variety of polymers and/or crosslinked polymeric networks

"Reconceptualising the Consumer Journey in the Digital Age – An Exploratory Study of the United Kingdom Retail Sector"

This extended conceptual abstract which describes research that is still in progress provides an analysis of the evolving factors that influence buyer behaviour in the vitally important retail sector. The research originated as a consultancy project concerned with buyer behaviour undertaken on behalf of a specialist Pay Per Click advertising agency in a UK university business school/commercial sector collaboration which then evolved into a research project in its own right

Minimal zero-sequences and the strong Davenport constant

AbstractLet G be a finite Abelian group and U(G) the set of minimal zero-sequences on G. If M1 and M2∈U(G), then set M1∼M2 if there exists an automorphism ϕ of G such that ϕ(M1)=M2. Let O(M) represent the equivalence class of M under ∼. In this paper, we consider problems related to the size of an equivalence class of sequences in U(G) and also examine a stronger form of the Davenport constant of G