A single-photon-sensitive intensified charge-coupled-device (ICCD) camera has been used to simultaneously detect, over a broad area, degenerate and nondegenerate photon pairs generated by the quantum-optical process of spontaneous parametric down-conversion. We have developed a new method for determining the quantum fourth- order correlations in spatially extended detection systems such as this...

lar findings (12), suggested the desirability of ob taining data of this type for carcinogenesis with 2-acetylaminofluorene. During the course of the work to be reported, Laird and Miller (5) pub lished a similar study on the effects of AAF. The data reported by the latter authors are in substan tial agreement with our findings and provide strong evidence that a similar chain of events is initi...

Work supported by the Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098 (for studies on ceramics and γ-TiAl), the U.S. Air Force Office of Scientific Research under Grant No. F49620-96-1-0478 under the auspices of the Multidisciplinary University Research Initiative on High Cycle Fatigue ...

Accordingly, it was of interest to study argininecanavanine relationships in actively multiplying tumor cells. Arginine has been shown to be essen tial for the growth of the Walker carcinosarcoma 256 in vitro (8) ; and, with the recent developments in tissue culture (9, 11) in this laboratory, it was possible to study the effects of canavanine on argi nine metabolism during tumor cell growth. T...

We propose an abductive diagnosis theory that integrates probabilistic, causal and taxonomic knowledge. Probabilistic knowledge allows us to select the most likely explanation; causal knowledge allows us to make reasonable inde­ pendence assumptions; taxonomic knowledge allows causation to be modeled at different lev­ els of detail, and allows observations be de­ scribed in different levels of ...

Ba salt of the Chil cotin Group (CG), sit u ated in the In te rior Pla teau phys io graphic re gion of cen tral Brit ish Co lum bia, cov ers an area of nearly 36 500 km. Its dis tri bu tion is en tirely within the re gion of BC that is most af fected by mountain pine bark beetle (MPBB) in fes ta tion (Fig 1). The CG is im me di ately un der lain by Pa leo zoic-Me so zoic base ment rocks with hi...

Polysynthetically-twinned TiAl crystals were deformed by compression with loading axis parallel and perpendicular to the lamellar interfaces. The deformation structures on the free surfaces were scanned using a dimension AFM with scan directions parallel and perpendicular to the lamellar interfaces. Abnormal deformation behaviors were observed to occur in both orientations. When the compression...