3,311 research outputs found

    Analysis of low temperature trapping and recombination in II-VI compounds using photodielectric techniques

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    Using photodielectric effect to detect densities of free and trapped carriers in II-VI compounds at cryogenic temperature

    Research on digital transducer principles. Volume 6 - The photodielectric effect in cadmium sulfide, 1 July 1967 - 30 June 1968

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    Cadmium sulfide photodielectric effect at cryogenic temperatures with bibliograph

    TiO2 film properties as a function of processing temperature, volume 3

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    Thin film TiO2 was produced at 150 C by chemical vapor deposition using hydrolysis of tetraisopropyl titanate. Films were amorphous as grown, but annealing in air caused crystallization, with anatase formed beginning at 350 C and rutile at 700 C. Density and index of refraction increased substantially with increasing anneal temperature, while etch susceptibility in HF and H2SO4 decreased. Comparison with literature data showed two groups of processes. One group yields films having properties that gradually approach those of rutile with increasing process temperature. The other group gives rutile directly at moderate temperatures. Deposition of amorphous film followed by etching and annealing is suggested as a means for pattern definition

    Ponticulin is the major high affinity link between the plasma membrane and the cortical actin network in Dictyostelium

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    Interactions between the plasma membrane and underlying actin-based cortex have been implicated in membrane organization and stability, the control of cell shape, and various motile processes. To ascertain the function of high affinity actin-membrane associations, we have disrupted by homologous recombination the gene encoding ponticulin, the major high affinity actin-membrane link in Dictyostelium discoideum amoebae. Cells lacking detectable amounts of ponticulin message and protein also are deficient in high affinity actin-membrane binding by several criteria. First, only 10-13% as much endogenous actin cosediments through sucrose and crude plasma membranes from ponticulin-minus cells, as compared with membranes from the parental strain. Second, purified plasma membranes exhibit little or no binding or nucleation of exogenous actin in vitro. Finally, only 10-30% as much endogenous actin partitions with plasma membranes from ponticulin-minus cells after these cells are mechanically unroofed with polylysine-coated coverslips. The loss of the cell\u27s major actin-binding membrane protein appears to be surprisingly benign under laboratory conditions. Ponticulin-minus cells grow normally in axenic culture and pinocytose FITC-dextran at the same rate as do parental cells. The rate of phagocytosis of particles by ponticulin-minus cells in growth media also is unaffected. By contrast, after initiation of development, cells lacking ponticulin aggregate faster than the parental cells. Subsequent morphogenesis proceeds asynchronously, but viable spores can form. These results indicate that ponticulin is not required for cellular translocation, but apparently plays a role in cell patterning during development

    Identification of Transit Service Gaps through Accessibility and Social Vulnerability Mapping in Miami-Dade County

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    Inadequate provision of public transportation services can lead to mobility-related social exclusion for disadvantaged population groups (e.g., lower-income families, the elderly), and limited accessibility to jobs, healthy food, and recreational as well as social activities. The aim of this study is to identify areas in Miami-Dade County, Florida, where disadvantaged populations lack transit-based access to these opportunities, and where transit service improvement could benefit these groups especially. This involves developing a transit-based accessibility index which uses timetable data from three public transit agencies. It also entails devising a vulnerability index based on a combination of socioeconomic variables to identify disadvantaged population groups with regards to mobility. Both indices can be combined into a service provision score which quantifies the presence of populations in need of transit service improvements. Results show that the combination of the different index maps and the application of Hotspot analysis can help to identify areas requiring transit service improvement in order to achieve accessibility equity. The analysis and interpretation of accessibility maps and selected demographic layers, such as percentage of households without vehicle, facilitates the identification of areas with above-average rates of users who rely on public transportation

    Pseudo-consimilarity and semi-consimilarity of complex matrices

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    AbstractIt is shown that the notion of consimilarity of n-by-n complex matrices is equivalent to each of the new concepts of pseudo-consimilarity and semi-consimilarity. This equivalence is unlike similarity in that pseudo-similarity and similarity are equivalent, while semi-similarity is a weaker relation than (pseudo-) similarity

    Conpseudosimilarity and consemisimilarity over a division ring

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    AbstractIt is shown that for n × n matrices over a division ring which is finite dimensional over its center, the notions of consimilarity, conpseudosimilarity and consemisimilarity are all equivalent, provided the conjugation is strong

    Mechanisms of actin rearrangements mediating platelet activation.

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