760 research outputs found
Ree Wheatgrass: Its Culture and Use
Ree wheatgrass, Agropyron intermedium and A. trichophorum, is a new pasture and hay grass released by the South Dakota Agricultural Experiment Station. It is closely related botanically to slender wheatgrass, Agropyron trachycaulum, and western wheatgrass, Agropyron smithii, both native to South Dakota and crested wheatgrass, Agropyron cristatum, native to the cold, dry plains of Russia and Siberia
Rancher, A Low Hydrocyanic Acid Forage Sorghum
Rancher sorghum has the lowest hydrocyanic acid content of any named forage sorghum variety in production. It contains about one-third of the hydrocyanic acid content of the low-acid Dakota Amber 39-30-S released in 1937 and only about one-tenth of the hydrocyanic acid content of commercial varieties (Table I). It was developed by the South Dakota Agricultural Experiment Station from a cross of the low hydrocyanic acid strain 39-30-S and a high acid strain 19-30-S and back crossed with the low acid strain 39-30-S. Both strains were selected from Dakota amber variety
Dual, an Early Grain and Forage Sorghum
Dual is a new grain and forage sorghum for South Dakota which grows taller than either Reliance or Norghum. It was developed to provide the stockman with a grain sorghum having a high yield of sweet, juicy forage for both fodder and silage. Tests conducted at several locations on widely different soil types and under varying climatic conditions show Dual is well adapted to the sorghum growing areas of the state. About 8,000 pounds of Dual seed were released by the South Dakota State College Agricultural Experiment Station to the County Crop Improvement Associations in the spring of 1958
Current density functional framework for spin-orbit coupling: Extension to periodic systems
Spin-orbit coupling induces a current density in the ground state, which
consequently requires a generalization for meta-generalized gradient
approximations. That is, the exchange-correlation energy has to be constructed
as an explicit functional of the current density and a generalized kinetic
energy density has to be formed to satisfy theoretical constraints. Herein, we
generalize our previously presented formalism of spin-orbit current density
functional theory [Holzer et al., J. Chem. Phys. 157, 204102 (2022)] to
non-magnetic and magnetic periodic systems of arbitrary dimension. Besides the
ground-state exchange-correlation potential, analytical derivatives such as
geometry gradients and stress tensors are implemented. The importance of the
current density is assessed for band gaps, lattice constants, magnetic
transitions, and Rashba splittings. For the latter, the impact of the current
density may be larger than the deviation between different density functional
approximations
Mandelbrot's 1/f fractional renewal models of 1963-67: The non-ergodic missing link between change points and long range dependence
The problem of 1/f noise has been with us for about a century. Because it is
so often framed in Fourier spectral language, the most famous solutions have
tended to be the stationary long range dependent (LRD) models such as
Mandelbrot's fractional Gaussian noise. In view of the increasing importance to
physics of non-ergodic fractional renewal models, I present preliminary results
of my research into the history of Mandelbrot's very little known work in that
area from 1963-67. I speculate about how the lack of awareness of this work in
the physics and statistics communities may have affected the development of
complexity science, and I discuss the differences between the Hurst effect, 1/f
noise and LRD, concepts which are often treated as equivalent.Comment: 11 pages. Corrected and improved version of a manuscript submitted to
ITISE 2016 meeting in Granada, Spai
Current density functional framework for spin–orbit coupling
Relativistic two-component density functional calculations are carried out in a non-collinear formalism to describe spin–orbit interactions, where the exchange–correlation functional is constructed as a generalization of the non-relativistic density functional approximation. Contrary to non-relativistic density functional theory (DFT), spin–orbit coupling, however, leads to a non-vanishing paramagnetic current density. Density functionals depending on the kinetic energy density, such as meta-generalized gradient approximations, should therefore be constructed in the framework of current DFT (CDFT). The latter has previously exclusively been used in the regime of strong magnetic fields. Herein, we present a consistent CDFT approach for relativistic DFT, including spin–orbit coupling. Furthermore, we assess the importance of the current density terms for ground-state energies, excitation energies, nuclear magnetic resonance shielding, and spin–spin coupling constants, as well as hyperfine coupling constants, g-shifts, and the nuclear quadrupole interaction tensor in electron paramagnetic resonance (EPR) spectroscopy. The most notable changes are found for EPR properties. The impact of the current-dependent terms rises with the number of unpaired electrons, and consequently, the EPR properties are more sensitive toward CDFT. Considerable changes are observed for the strongly constrained and appropriately normed functionals, as well as the B97M family and TASK. The current density terms are less important when exact exchange is incorporated. At the same time, the current-dependent kernel ensures the stability of response calculations in all cases. We, therefore, strongly recommend to use the framework of CDFT for self-consistent spin–orbit calculations
Calculations of current densities and aromatic pathways in cyclic porphyrin and isoporphyrin arrays
Magnetically induced current density susceptibilities have been studied for a number of cyclic ethyne and butadiyne-bridged porphyrin and isoporphyrin arrays. The current density susceptibilities have been calculated using the gauge-including magnetically induced current (GIMIC) method, which is interfaced to the TURBOMOLE quantum chemistry code. Aromatic properties and current pathways have been analyzed and discussed by numerical integration of the current density susceptibilities passing selected chemical bonds yielding current strength susceptibilities. Despite the interrupted p-framework, zinc(II) isoporphyrin sustains a ring current of ca. 10 nA T-1. Porphyrin and isoporphyrin dimers sustain a significant current strength at the linker, whereas the larger porphyrinoid arrays sustain mainly local ring currents. Isoporphyrin dimers with saturated meso carbons have strong net diatropic ring-current strengths of 20 nA T-1 fulfilling Huckels aromaticity rule. Porphyrin trimers and tetramers exhibit almost no current strength at the linker. The porphyrin moieties maintain their strong net diatropic ring current.Peer reviewe
An agent-based approach to integrated assessment modelling of climate change
There is an ongoing discussion concerning the relationship between social welfare and climate change, and thus the required level and type of measures needed to protect the climate. Integrated assessment models (IAMs) have been extended to incorporate technological progress, heterogeneity and uncertainty, making use of a (stochastic) dynamic equilibrium approach in order to derive a solution. According to the literature, the IAM class of models does not take all the relationships among economic, social and environmental factors into account. Moreover, it does not consider these interdependencies at the micro-level, meaning that all possible consequences are not duly examined. Here, we propose an agent-based approach to analyse the relationship between economic welfare and climate protection. In particular, our aim is to analyse how the decisions of individual agents, allowing for the trade-off between economic welfare and climate protection, influence the aggregated emergent economic behaviour. Using this model, we estimate a damage function, with values in the order 3% - 4%for 2 C temperature increase and having a linear (or slightly concave) shape. We show that the heterogeneity of the agents, technological progress and the damage function may lead to lower GDP growth rates and greater temperature-related damage than what is forecast by models with solely homogeneous (representative) agents
φ-Aromaticity in prismatic {Bi}-based clusters
The occurrence of aromaticity in organic molecules is widely accepted, but its occurrence in purely metallic systems is less widespread. Molecules comprising only metal atoms (M) are known to be able to exhibit aromatic behaviour, sustaining ring currents inside an external magnetic field along M–M connection axes (σ-aromaticity) or above and below the plane (π-aromaticity) for cyclic or cage-type compounds. However, all-metal compounds provide an extension of the electrons’ mobility also in other directions. Here, we show that regular {Bi} prisms exhibit a non-localizable molecular orbital of f-type symmetry and generate a strong ring current that leads to a behaviour referred to as φ-aromaticity. The experimentally observed heterometallic cluster [{CpRu}Bi]–, based on a regular prismatic {Bi} unit, displays aromatic behaviour; according to quantum chemical calculations, the corresponding hypothetical Bi prism shows a similar behaviour. By contrast, [{(cod)Ir}Bi] features a distorted Bi moiety that inhibits φ-aromaticity
- …