Effects of Species, Water, and Nitrogen on Competition Among Three Prairie Grasses

We conducted an experiment to investigate effects of species, water (W), and nitrogen (N) on competition among little bluestem (Schizachyrium scoparium), sideoats grama (Bouteloua curtipendula), and indiangrass (Sorghastrum nutans). All biomass parameters and the root:shoot ratio of little bluestem were reduced by the presence off 1 of 2 other species, and its shoot biomass and total biomass were both increased by addition of N. Root and shoot biomass of sideoats grama were reduced by the presence of indiangrass and its total biomass was reduced by the presence of itself, whereas its shoot biomass was increased by addition of W at the highest level. Root biomass and total biomass of indiangrass were increased by N and that response pattern was preserved for root biomass but lost for total biomass when W was added. We conclude that grass seedlings were affected by species more than by levels of W and N, interspecific competition was more important than intraspecific competition, and both N and W effects occurred only in the highest levels of addition with some interaction

A systematic study of neutral and charged 3d-metal trioxides and tetraoxides

Using density functional theory with generalized gradient approximation, we have performed a systematic study of the structure and properties of neutral and charged trioxides (MO3) and tetraoxides (MO4) of the 3d-metal atoms. The results of our calculations revealed a number of interesting features when moving along the 3d-metal series. (1) Geometrical configurations of the lowest total energy states of neutral and charged trioxides and tetraoxides are composed of oxo and/or peroxo groups, except for CuO3 − and ZnO3 − which possess a superoxo group, CuO4 + and ZnO4 + which possess two superoxo groups, and CuO3 +, ZnO3 +, and ZnO4 −which possess an ozonide group. While peroxo groups are found in the early and late transition metals, all oxygen atoms bind chemically to the metal atom in the middle of the series. (2) Attachment or detachment of an electron to/from an oxide often leads to a change in the geometry. In some cases, two dissociatively attached oxygen atoms combine and form a peroxo group or a peroxo group transforms into a superoxo group and vice versa. (3) The adiabatic electron affinity of as many as two trioxides (VO3 and CoO3) and four tetraoxides (TiO4, CrO4, MnO4, and FeO4) are larger than the electron affinity of halogen atoms. All these oxides are hence superhalogens although only VO3 and MnO4 satisfy the general superhalogen formula

Interactions of a Mn atom with halogen atoms and stability of its half-filled 3d-shell

Using density functional theory with hybrid exchange-correlation potential, we have calculated the geometrical and electronic structure, relative stability, and electron affinities of MnX ncompounds (n = 1–6) formed by a Mn atom and halogen atoms X = F, Cl, and Br. Our objective is to examine the extent to which the Mn–X interactions are similar and to elucidate if/how the half-filled 3d-shell of a Mn atom participates in chemical bonding as the number of halogen atoms increases. While the highest oxidation number of the Mn atom in fluorides is considered to be +4, the maximum number of halogen atoms that can be chemically attached in the MnX n −anions is 6 for X = F, 5 for X = Cl, and 4 for X = Br. The MnCl n and MnBr n neutrals are superhalogens for n ≥ 3, while the superhalogen behavior of MnF n begins with n = 4. These results are explained to be due to the way different halogen atoms interact with the 3d electrons of Mn atom

Does N-2(-) exist? A coupled-cluster study

Potential energy curves of the ground-state N2 molecule and its doublet N−2 anion are calculated at the coupled-cluster level with single and double excitations and with noniterative triples [CCSD(T)] as well as with the multireference averaged-quadratic coupled-cluster (MR-AQCC) method. The N−2 anion is shown to be temporary and decays to its neutral parent plus a free electron at bond lengths shorter than ≈1.4 and larger than ≈2.5 Å. Thus, the N−2 anion exists within the 1.4⩽R(N–N)⩽2.5 Å range at the Born–Oppenheimer approximation

An all-electron density functional theory study of the structure and properties of the neutral and singly charged M-12 and M-13 clusters: M = Sc-Zn

The electronic and geometrical structures of the M 12 and M 13 clusters where M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn along with their singly negatively and positively charged ions are studied using all-electron density functional theory within the generalized gradient approximation. The geometries corresponding to the lowest total energy states of singly and negatively charged ions of V13, Mn12, Co12, Ni 13, Cu 13, Zn 12, and Zn 13 are found to be different from the geometries of the corresponding neutral parents. The computed ionizationenergies of the neutrals, vertical electron detachment energies from the anions, and energies required to remove a single atom from the M 13 and M 13 + clusters are in good agreement with experiment. The change in a total spin magnetic moment of the cation or anion with respect to a total spin magnetic moment of the corresponding neutral is consistent with the one-electron model in most cases, i.e., they differ by ±1.0 μ B. Exceptions are found only for Sc12 −, Ti12 +, Mn12 −, Mn12 +, Fe12 −, Fe13 +, and Co12 +

An examination of the perceived impact of a continuing interprofessional education experience on opiate prescribing practices

Chronic pain is increasingly recognized as a public health problem. We assessed the effectiveness of a multi-modal, interprofessional educational approach aimed at empowering healthcare professionals to make deliberative changes, especially in opiate prescribing practices. Education activities included enduring webcasts, regional interprofessional roundtable events, and state-level conference presentations within targeted Kentucky and West Virginia regions of the United States. Over 1,000 participants accessed the various activities. For the live events, the largest groups reached included nurses (38.1%), nurse practitioners (31.2%), and physicians (22.1%). In addition to our reach, higher levels of educational effectiveness were measured, specifically, learner’s intentions to change practice patterns, confidence in meeting patient’s needs, and knowledge of pain management guidelines. The majority of the conference (58%) and roundtable (69%) participants stated they intend to make a practice change in one or more areas of chronic pain patient management in post-event evaluation. Differences in pre- and post-activity responses on the measures of confidence and knowledge, with additional comparison to a control population who were not in attendance, were analyzed using non-parametric tests of significance. While neither activity produced significant changes in confidence from pre-activity, participants were more confident post-activity than their control group peers. There were significant changes in knowledge for both live event and webcast participants. Impactful chronic pain continuing the education that emphasizes collaborative care is greatly needed; these results show that the approaches taken here can impact learner’s knowledge and confidence, and hold potential for creating change in how opioid prescribing is managed