Near band-edge optical properties of cubic GaN with and without carbon doping
We report the results of studying the optical properties of cubic GaN thin films with photoluminescence and photoluminescence excitation spectroscopies. The films are deposited by plasma-assisted molecular beam epitaxy on GaAs (001) substrates, with and without intentional doping with carbon atoms (p-type doping). The evolution of the optical spectra of the C-doped samples is consistent with a picture in which carbon enters into N-vacancies at low concentrations, producing a marked improvement in the crystalline properties of the material. At higher concentrations it begins to form complexes, possibly due to interstitial occupation. The temperature dependence on the absorption edge of the doped material is also measured and is analyzed with standard theoretical models.
APL\?
This paper describes a version of APL based upon the dictionary [1], but significantly simplified and enhanced, and directly usable on any machine that provides ASCII characters. It also describes salient features of a C implementation that has been tested on several machines, and is available as freeware. There have been four primary motivations for this work:To provide an APL system for use in teaching mathematics and related topics that is modern, free, and transportable.
To devise a spelling scheme based on the ASCII alphabet that preserves the major advantages of the one-letter words based on the special alphabet commonly used in APL.
To exploit the advantages of breaking from the strict conformance with earlier APL that is normally obligatory in commercial systems.
To explore an unusual style of C programming that makes heavy use of pre-processing facilities.

Examples of the use of the language in a variety of topics are provided in an appendix.
We are indebted to a number of colleagues for advice and help: Anthony Howe, David Steinbrook, Bob Bernecky, Mark Czerwinski, L.J. Dickey, Jiri Dvorak, James Hui, Eric Iverson, Paul Jackson, and Roland Pesch.
Pseudo‐Chediak‐Higashi Anomaly in Acute Myeloid Leukemia (M2) of Childhood
The frequency and clinical significance of the pseudo‐Chediak‐Higashi (PCH) anomaly were studied in 20 children with acute myeloid leukemia (AML) M2 in the FAB nomenclature. PCH granules were recognized as giant eosinophilic granules, measuring up to 5μ, in the cytoplasm of leukemic cells on smears. At the electron microscope level, most PCH granules were round to oval and outlined by a limiting membrane, and contained homogeneous, granular, crystalloid, rod‐like or myelin‐like materials. The PCH anomaly was demonstrable in five (25.0%) of the 20 patients, which indicates that the anomaly is not rare in childhood AML M2. There were no differences between PCH anomaly‐positive and PCH anomaly negative groups with regard to hepatosplenomegaly, hemoglobin levels, white blood cell counts, bone marrow cellularity, t(8q‐, 21q+) chromosome abnormalities or prognoses. Circulating leukemic cells were observed less frequently in the PCH anomaly‐positive group than in the PCH anomaly‐negative group (p <0.05); the leukemic cells were not demonstrable in three of the five patients in the former group, although they were detected in all 15 patients in the latter group. The existence of PCH granules and/or a defect of the cytoskeleton responsible for the PCH anomaly in leukemic cells may impede their movement from the bone marrow to the peripheral blood.