Fat Deposits in Certain Ericacere

The purpose of this work was to investigate the structures of certain available plants of the family Ericacere with special interest in fat deposits in the tissues. HISTORICAL. Priestly and Hinchliffe (8) have called attention to the characteristic appearance of plants growing in peat moors of England. These plants are of a stunted nature, dark green in color, leathery in texture, and with very little leaf surface. These characteristics, along with certain others, have led to these plants being grouped with xerophytes. This seems strange, as xerophytism is associated, normally, with scarcity of water

Modeling solar wind mass‐loading in the vicinity of the Sun using 3‐D MHD simulations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106053/1/jgra50759.pd

EULERIAN FORMULATION FOR LARGE-DISPLACEMENT ANALYSIS OF SPACE FRAMES

Accepted versio

Auroral Plasma Lines: A First Comparison of Theory and Experiment

In this preliminary report on low-energy (0.3 to 3 eV) secondary electrons in the auroral E layer (90 to 150 km), we compare intensities of plasma lines observed with the Chatanika radar to theoretical predictions obtained from a detailed numerical model. The model calculations are initiated with a flux of energetic auroral primary electrons which enter the atmosphere and lose energy to electrons, ions, and neutrals through a combination of elastic and inelastic collisions. This flux is chosen in order that the total calculated ionization rate matches one that is deduced from the radar measurements. From these same calculations the steady state secondary electron flux is deduced as a function of altitude, energy, and pitch angle. This flux is used to calculate plasma line intensities which are then compared with observed intensities. Initial comparisons suggest that the plasma line theory, when applied to low altitudes, must include the effect of electron-neutral collisions. When this is done, the good agreement obtained between theory and experiment indicates the promise of this approach for the study of low-energy auroral electrons

Alfvén Wave Turbulence as a Coronal Heating Mechanism: Simultaneously Predicting the Heating Rate and the Wave-induced Emission Line Broadening

We test the predictions of the Alfvén Wave Solar Model (AWSoM), a global wave-driven magnetohydrodynamic (MHD) model of the solar atmosphere, against high-resolution spectra emitted by the quiescent off-disk solar corona. AWSoM incorporates Alfvén wave propagation and dissipation in both closed and open magnetic field lines; turbulent dissipation is the only heating mechanism. We examine whether this mechanism is consistent with observations of coronal EUV emission by combining model results with the CHIANTI atomic database to create synthetic line-of-sight spectra, where spectral line widths depend on thermal and wave-related ion motions. This is the first time wave-induced line broadening is calculated from a global model with a realistic magnetic field. We used high-resolution SUMER observations above the solar west limb between 1.04 and 1.34 R o at the equator, taken in 1996 November. We obtained an AWSoM steady-state solution for the corresponding period using a synoptic magnetogram. The 3D solution revealed a pseudo-streamer structure transversing the SUMER line of sight, which contributes significantly to the emission; the modeled electron temperature and density in the pseudo-streamer are consistent with those observed. The synthetic line widths and the total line fluxes are consistent with the observations for five different ions. Further, line widths that include the contribution from the wave-induced ion motions improve the correspondence with observed spectra for all ions. We conclude that the turbulent dissipation assumed in the AWSoM model is a viable candidate for explaining coronal heating, as it is consistent with several independent measured quantities.National Science Foundation (U.S.) (Grant AGS-1322543

High-Pressure Neutron-Scattering Studies of Graphite and Stage-Two Graphite-SbCl₅

The longitudinal-acoustic (LA) phonons propagating along the c axis in highly oriented pyrolytic graphite (HOPG) were investigated as a function of pressure up to 20 kbar using inelastic-neutron-scattering techniques. The phonon frequencies varied as (P,q)=A(P)sin[c(P)q/2], where A(P) and c(P) indicate the pressure dependences of the zone-center LO frequency of B1g1 symmetry and of the c-axis lattice spacing, respectively. From the measurements, the mode Grüneisen parameter for the LA branch was estimated to be 1.5 x 10-2 kbar-1 (independent of q); the elastic constant C33 for HOPG was found to be 3.40 x 1011 dyn/cm2 at 1 bar with a pressure coefficient of (1/C33)(dC33/dP)=2.91 x 10-2 kbar-1. The measured c-axis spacings were 6.71 and 12.72 Å for HOPG and stage-2 SbCl5-intercalated graphite, respectively, at atmospheric pressure; the corresponding compressibilities (1/c)(dc/dP) were -2.24 x 10-3 kbar-1 (HOPG) and -2.28 x 10-3 kbar-1 (SbCl5). Elastic-neutron-scattering studies up to 20 kbar were undertaken to search for stage transformations, but no evidence of any phase transition was observed

Fate of legume and fertilizer nitrogen-15 in a long-term cropping systems experiment

Includes bibliographical references (pages 914-915).Relying more on biological N2 fixation has been suggested as a way to meet one of the major challenges of agricultural sustainability. A 15N study was conducted to compare the fate of applied legume and fertilizer N in a long-term cropping systems experiment. Nitrogen-15-1abeled red clover (Trifolium pratense L.) and (NH4)2SO4 ere applied microplots within the low-input and conventional cropping systems of the Farming Systems Trial at the Rodale Institute Research Center in Pennsylvania. The 15SN was applied to soil and traced into corn (Zea mays L.) in 1987 and 1988. Residual 15SN was also traced into second-year spring barley (Hordeum vulgare L.). Legume and fertilizer 15SN remaining in soil was measured and loss of N was calculated by difference. More fertilizer than legume N was recovered by crops (40 vs. 17% of input), more legume than fertilizer N was retained in soil (47 vs. 17% of input), and similar amounts of N from both sources were lost from the cropping systems (39% of input) over the 2-yr period. More fertilizer than legume N was lost during the year of application (38 vs. 18% of input), but more legume than fertilizer N was lost the year after application (17 vs. 4% of input). Residual fertilizer and legume 15SN was distributed similarly among soil fractions. Soil microbial biomass was larger in the legume-based system. A larger, but not necessarily more active, soil microbial biomass was probably responsible for the greater soil N supplying capacity in the legume-based compared with fertilizer-based system