Cosmic ray positron and negatron spectra between 20 and 800 MeV measured in 1974

A balloon-borne spark chamber magnetic spectrometer was used to measure separate spectra of positrons and negatrons in two flights during summer, 1974. The total electron flux is about 0.3 m(-2) s(-1) sr(-1) MeV(-1) between 70 and 800 MeV, and increases toward lower energies. The positron spectrum decreases sharply toward lower energies from a value of about 0.08 m(-2) s(-1) sr(-1) MeV(-1) at 650 MeV, and only upper limits are obtained for positrons below 200 MeV. At energies above 180 MeV, the spherically symmetric Fokker-Planck equation provides reasonable fits to both the positron and total electron data. At energies below 180 MeV the data are consistent with a continuation of the same diffusion coefficient and local source of negatrons, or a change in the diffusion coefficient to a constant value

Management of imidazolinone-tolerant (IT) rice in drill- and water-seeded rice

Field studies were conducted over two years in drill- and water-seeded rice to evaluate weed control and crop response with imazethapyr programs. Barnyardgrass [Echinochloa crus-galli (L.) Beauv.] was evaluated with imazethapyr applied alone at various rates and timings. Imazethapyr controlled barnyardgrass 95 to 97% with a soil application at 87 or 70 g/ha fb 53 or 70 g/ha EPOST or LPOST. A single EPOST application of imazethapyr at 140 g/ha controlled barnyardgrass and rice yield was equal to or above those treatments receiving two applications of imazethapyr. Research was also conducted at Crowley, LA and Rayne, LA to evaluate the addition of a herbicide with broadleaf activity into imazethapyr programs applied alone early postemergence (EPOST) and in combination with imazethapyr postemergence (POST). Weeds evaluated included barnyardgrass, red rice (Oryza sativa L.), alligatorweed [Alternanthera philoxeroides (Mart.) Griseb.], and hemp sesbania [Sesbania exaltata (Raf.) Rydb. ex A.W. Hill]. Treatments consisting of imazethapyr applied at 87 g/ha alone to the soil fb a POST imazethapyr application at 53 g/ha controlled barnyardgrass above 90% late season in all studies, expect in water-seeded rice when an imazethapyr application was made at the three- to four-leaf rice stage. Red rice control with a total imazethapyr program was equivalent to, or higher, than other treatments in both drill- and water-seeded studies. Single imazethapyr applications resulted in reduced control of red rice indicating two applications of imazethapyr are required to obtain adequate control. Alligatorweed control increased with soil applications of imazethapyr. However, alligatorweed control with imazethapyr as the only herbicide in a weed control program was inconsistent and suggested only suppression. Treatments receiving a broadleaf herbicide application increased hemp sesbania control as compared with the total imazethapyr program; however, treatments with bensulfuron and triclopyr were inconsistent at controlling hemp sesbania. In drill-seeded studies, hemp sesbania was less of a problem and red rice had a greater impact on rice yield. Rice yields with total imazethapyr programs were equal to, or higher than, other treatments. However, in water-seeded studies, hemp sesbania growth was favored and yields from rice treated with broadleaf herbicides were higher than total imazethapyr programs

Applications Spacelab Missions

The plans of the Office of Space and Terrestrial Applications for Shuttle/Spacelab missions are presented. The current program contains a dedicated low-gravity mission (Spacelab 3 Mission) and several minor missions planned for flight during 1980- 1982. These minor missions have either Materials Processing or Earth Viewing emphasis. Several representative experiments are used to illustrate the Applications Spacelab Program

Cellular Bases of Brain Energy Metabolism and Their Relevance to Functional Brain Imaging: Evidence for a Prominent Role of Astrocytes

Survey of Brain Energy Metabolism at the Organ and Regional Level

Constraining Stellar Feedback: Shock-ionized Gas in Nearby Starburst Galaxies

(abridged) We investigate the properties of feedback-driven shocks in 8 nearby starburst galaxies using narrow-band imaging data from the Hubble Space Telescope (HST). We identify the shock--ionized component via the line diagnostic diagram \oiii/\hb vs. \sii (or \nii)/\ha, applied to resolved regions 3--15 pc in size. We divide our sample into three sub-samples: sub-solar (Holmberg II, NGC 1569, NGC 4214, NGC 4449, and NGC 5253), solar (He 2-10, NGC 3077) and super-solar (NGC 5236) for consistent shock measurements. For the sub-solar sub-sample, we derive three scaling relations: (1) $L_{shock} \propto {SFR}^{~0.62}$, (2) $L_{shock} \propto {\Sigma_{SFR,HL}}^{~0.92}$, and (3) $L_{shock}/L_{tot} \propto {(L_H/L_{\odot,H})}^{-0.65}$, where $L_{shock}$ is the \ha luminosity from shock--ionized gas, ${\Sigma_{SFR,HL}}$ the SFR per unit half-light area, $L_{tot}$ the total \ha luminosity, and $L_H/L_{\odot,H}$ the absolute H-band luminosity from 2MASS normalized to solar luminosity. The other two sub--samples do not have enough number statistics, but appear to follow the first scaling relation. The energy recovered indicates that the shocks from stellar feedback in our sample galaxies are fully radiative. If the scaling relations are applicable in general to stellar feedback, our results are similar to those by Hopkins et al. (2012) for galactic super winds. This similarity should, however, be taken with caution at this point, as the underlying physics that enables the transition from radiative shocks to gas outflows in galaxies is still poorly understood.Comment: 29 pages, 14 figures, accepted for publication in the Ap

Iosipescu Shear Test Apparatus Applied to Wood Composites

In-plane and transverse (through-the-thickness) shear strength properties were evaluated for three wood composite materials. A modified Iosipescu test apparatus was used to determine shear strength relative to the six possible material orientations. In-plane shear was also characterized using ASTM D1037-87 test standards. The Iosipescu shear test method was developed originally for metals testing. However, different forms of the test device have evolved for purposes of shear evaluation with numerous nonisotropic materials being evaluated. Previous research for various materials has shown satisfactory results with repeatability and apparent shear failure. The current research specifically utilized the University of Wyoming version of the original shear test device. Iosipescu test results for in-plane shear strength were comparable to values derived from the ASTM test method. Transverse shear strength values were found to exceed the magnitude of previously published ASTM test results. Greater directional or material orientation differences were observed for transverse shear properties

Toward mixed-element meshing based on restricted Voronoi diagrams

In this paper we propose a method to generate mixed-element meshes (tetrahedra, triangular prisms, square pyramids) for B-Rep models. The vertices, edges, facets, and cells of the final volumetric mesh are determined from the combinatorial analysis of the intersections between the model components and the Voronoi diagram of sites distributed to sample the model. Inside the volumetric regions, Delaunay tetrahedra dual of the Voronoi diagram are built. Where the intersections of the Voronoi cells with the model surfaces have a unique connected component, tetrahedra are modified to fit the input triangulated surfaces. Where these intersections are more complicated, a correspondence between the elements of the Voronoi diagram and the elements of the mixedelement mesh is used to build the final volumetric mesh. The method which was motivated by meshing challenges encountered in geological modeling is demonstrated on several 3D synthetic models of subsurface rock volumes