THE RESPONSE OF LEGUME SEEDLINGS TO LIGHT INTENSITY, TEMPERATURE, AND SOIL MOISTURE

Abstract not availabl

High Throughput Study of the Structure Sensitive Decomposition of Tartaric and Aspartic Acid on Surfaces Vicinal to Cu(111) and Cu(100)

<p>There are many reactions that are sensitive to the surface structure of a catalyst. In order to obtain a comprehensive understanding of structure sensitive surface chemistry we use Surface Structure Spread Single Crystals (S4Cs) that expose a continuous distribution of crystal planes across their surfaces. Those crystal planes that lack mirror symmetry contain terraces, monatomic steps, and kinks and can be described as chiral with an R or an S orientation. When coupled with spatially resolved surface analysis techniques, S4Cs can be used to study the effects of surface structure and chirality on surface chemistry across a continuous distribution of crystal planes. A set of six Cu S4Cs has been created that spans all possible crystal planes of Cu. The Cu(111) S4C was used to study the structure sensitivity of L- and D-tartaric acid (TA) decomposition and the Cu(100) S4C was used to study the structure sensitivity of L-4-13C and D-aspartic acid (AA) decomposition. Isothermal Temperature Programmed Reaction Spectroscopy (TPRS) was implemented in which the S4Cs with monolayers of TA and AA were held at a temperature below the temperature of peak decomposition observed in a standard TPR experiment (heating at 1 K/s). At various times during isothermal heating, the surface was cooled to quench the reaction. Spatially resolved X-ray Photoelectron Spectroscopy (XPS) was performed to identify those regions on the surface in which the adsorbates had decomposed and those in which they were still intact. On the Cu(111) S4C which exposes both (100) and (110) step edges, TA decomposition is most sensitive to the density of (100) steps. AA decomposition on the Cu(100) S4C was enantioselective: L-AA-4-13C decomposed on S surfaces before R surfaces while D-AA decomposed on R surfaces before S surfaces. The decomposition of CH3CH2OH, CD3CD2OD, and CF3CH2OH on Zn was studied using temperature programmed reaction spectroscopy (TPRS). The decomposition products of each reaction were determined and a reaction mechanism was proposed for CH3CH2OH decomposition based on the product ratios and peak temperature locations. The CH3CH2OH decomposition mechanism includes the formation of two intermediate species on the surface: CH3CH2- to form CH2=CH2 and CH3CH2O- to form CH3CH=O.</p

Technical paper: United States Department of Commerce, Bureau of Standards, 117

Technical paper issued by the Bureau of Standards over toluol-recovery, known as light oil. The methods used in the toluol-recovery are presented and discussed. This paper includes tables, and illustrations

CH3CH2OH, CD3CD2OD, and CF3CH2OH Decomposition on ZnO(1(1)over-bar00)

The decomposition of CH3CH2OH, CD3CD2OD, and CF3CH2OH on Zn (1 (1) over bar 00) was studied using temperature programmed reaction spectroscopy. CH3CH=O (CD3CD=O, CF3CH=O), CH2=CH2 (CD2=CD2, CF2=CH2), H2O (D2O) and H-2 (D-2) were formed in all cases. The CH3CH2OH decomposition mechanism includes the formation of two intermediate species on the surface: CH3CH2- bonded to surface lattice O atoms decomposes to form CH2=CH2 while CH3CH2O- bonded to surface Zn atoms decomposes to form CH3CH=O. A significant isotope effect observed for the formation of CH2=CH2 versus CD2=CD2 suggests that C-H(D) bond breaking at the beta-carbon is the rate-limiting step in CH3CH2- (CD3CD2-) decomposition. Decomposition of CF3CH2OH leaves F-atoms on the surface as a result of beta-fluoride elimination in CF3CH2-. A significant F substituent effect in desorption of CF3CH=O versus CH3CH=O indicates that the CF3 group increases the barrier to the beta-hydride elimination step yielding CF3CH=O and suggests that the transition state is cationic, C delta+ center dot center dot center dot H delta+.111sciescopu

Child Attributions Mediate Relationships Between Violence Exposure and Trauma Symptomology

Violence and trauma exposure have been increasingly investigated as contributing to a range of negative outcomes in child physical, cognitive, emotional, social, and psychological functioning, particularly among youth who are racial/ethnic minorities. This study presents findings related to children's attributions of their violence and trauma exposure. Attributions are inferences made about the cause of an event, situation, or action, with internal, stable, and global attributions most likely to lead to negative psychological outcomes. Data were drawn from an on-going clinical intervention study with families at risk for child maltreatment and/or neglect residing in a large metropolitan city on the East Coast. Mediation models provide evidence for a mediated relationship between violence exposure and PTSD through child attribution. Children develop their definitions of violence, formulate reasons why the violence occurs, and react to violence based on interpreting and developing cognitive attributions and schema about their experiences with violence in order to adaptively cope