3D position readout from thick scintillators

A novel technique has been developed and tested for the three-dimensional measurement of position in SPECT-PET detectors. Results are presented for 2 and 20 mm thick NaI(Tl) planar crystals. In a plane of crystal, a coordinate resolution of about 1 mm (rms error) is demonstrated. The depth of interaction (DOI) is measured with an rms error of about 2 mm using light cone parameters.     

Visualizing dispersion morphology via ultra-rapid freezing/transmission electron microscopy

Optical microscopy has been a useful technique for visualizing aqueous dispersions, but it lacks the high resolution available with transmission electron microscopy (TEM). In order to withstand the vacuum of the electron microscope, water-based systems must be either dried or frozen, but this distorts morphology. The ultra-rapid freezing technique can be used in such studies to preserve microstructure and also be compatible with the vacuum of the electron microscope. Also known as cryo-TEM, this technique has been used in coatings research to visualize the morphologies of a variety of aqueous dispersions. Besides being consistent with what we already know optically, these complementary techniques of ultra-rapid freezing and transmission electron microscopy now permit us a unique view of fluid microstructure far below the limit of optical microscopy.     

Biracial learning teams and race relations in the classroom: Four field experiments using Teams-Games-Tournament.

Investigated the effects of Teams-Games-Tournament (TGT), an instructional strategy employing biracial learning teams and instructional games, on cross-racial friendship in integrated classes. Four experiments comparing TGT and control treatments are reviewed, involving a total of 558 students in Grades 7–12. Sociometric measures were used to assess TGT effects on the number of cross-racial friendship choices and the percentage of cross-racial choices over all choices made. Chi-square analyses showed significant positive TGT effects on 7 of 13 measures of numbers of cross-racial choices and 3 of 13 on percentage of cross-racial choices over all choices. These results indicate that TGT is an effective means of increasing cross-racial friendship in integrated classes. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When does cooperative learning increase student achievement?

Reviews research on the achievement effects of cooperative learning instructional methods, in which students work in small groups to learn academic materials. Methodologically adequate field experiments of at least 2 wks' duration in regular elementary and secondary schools indicate that among cooperative learning methods in which students study the same material together, only methods that provide group rewards based on group members' individual learning consistently increase student achievement more than control methods. Cooperative learning methods in which each group member has a unique subtask have positive achievement effects only if group rewards are provided. Group rewards and individual accountability are held to be essential to the instructional effectiveness of cooperative learning methods. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Plant shutdown scheduling using fuzzy logic

The performance objectives of shutdown planning are discussed. The background to and application of a package designed to plan and control shutdowns is described.     

Neutralization of gaseous emissions in the petrochemical,chemical, and gas industries

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 5, pp. 30–32, May, 1990.     

Effect of recombinant human manganese superoxide dismutase on radiosensitivity of murine B cell leukemia (BCL1) cells

Recombinant human manganese superoxide dismutase (SOD) protects cells from oxidative damage and is known to ameliorate post-irradiation damage in mice exposed to whole body or localized chest irradiation. The concept behind the present experiments was to investigate whether it is possible to improve the outcome in leukemia following total body irradiation used as part of the conditioning prior to allogeneic bone marrow transplantation. We determined whether SOD protects leukemic cells from the effects of ionizing irradiation both in vitro and in vivo. Murine B cell leukemia (BCL1) cells, derived from tumor-bearing mice, were irradiated in vitro with or without SOD and injected into BALB/c mice. All mice receiving 10(4) unirradiated BLC1 cells developed leukemia and died within 19-39 days. In vitro exposure of BCL1 cells to 800 cGy or 1600 cGy abolished the potential to induce leukemia by inoculation with 10(4) or 10(6) BCL1 cells, respectively. Addition of SOD in vitro during irradiation increased the resistance of BCL1 cells to ionizing irradiation; all mice receiving 10(6) BCL1 cells previously exposed in vitro to 1200 cGy in the presence of SOD died of leukemia, whereas only 40% of mice receiving a similar inoculum of irradiated BCL1 cells died of leukemia. In contrast, when BCL1-bearing mice were irradiated with 600-800 cGy with or without intravenous injection of SOD (100 mg/kg) 30 minutes prior to irradiation, development of leukemia was unaffected. Residual leukemia cells following therapy were assessed by adoptive transfer of 10(5) spleen cells to secondary BALB/c recipients.(ABSTRACT TRUNCATED AT 250 WORDS)