Simulation of inhomogeneous distributions of ultracold atoms in an optical lattice via a massively parallel implementation of nonequilibrium strong-coupling perturbation theory

We present a nonequilibrium strong-coupling approach to inhomogeneous systems of ultracold atoms in optical lattices. We demonstrate its application to the Mott-insulating phase of a two-dimensional Fermi-Hubbard model in the presence of a trap potential. Since the theory is formulated self-consistently, the numerical implementation relies on a massively parallel evaluation of the self-energy and the Green's function at each lattice site, employing thousands of CPUs. While the computation of the self-energy is straightforward to parallelize, the evaluation of the Green's function requires the inversion of a large sparse $10^d\times 10^d$ matrix, with $d > 6$. As a crucial ingredient, our solution heavily relies on the smallness of the hopping as compared to the interaction strength and yields a widely scalable realization of a rapidly converging iterative algorithm which evaluates all elements of the Green's function. Results are validated by comparing with the homogeneous case via the local-density approximation. These calculations also show that the local-density approximation is valid in non-equilibrium setups without mass transport.Comment: 14 pages, 9 figure

Grain Banks in South Dakota

Grain banking is a relatively new feed merchandising technique being used by country elevators in South Dakota. In simple terms, grain banking is any kind of an arrangement whereby farmers deposit feed grain at the elevator, and later withdraw it in one form or another, generally as mixed feed. Many country elevators have shown interest in grain banking as a means of utilizing surplus storage capacity and expanding services offered to farmers. Because of this interest, information is needed to guide elevator managers in developing more efficient and uniform methods of grain banking. This study obtained information about the operating policies and procedures and economic benefits of grain banking for elevators in South Dakota. The objectives were: (1) to determine the extent and interest in grain banking, (2) to determine the importance of grain banking to storage, feed processing, and feed merchandising programs, and (3) to develop guides for more efficient use and management of grain banks and feed mills

Thermal analysis of the ultraviolet imager camera and electronics

The Ultraviolet Imaging experiment has undergone design changes that necessiate updating the reduced thermal models (RTM's) for both the Camera and Electronics. In addition, there are several mission scenarios that need to be evaluated in terms of thermal response of the instruments. The impact of these design changes and mission scenarios on the thermal performance of the Camera and Electronics assemblies is discussed

Economic and Organizational Aspects of Cooperative Feedlots

The cooperative organization of specialized large-scale feedlots, described in this bulletin, is not the only means open to South Dakota farmers and investors who want to enter the feeding business. A study of the cooperative feedlot was made because so little is known of its potential comparted with other forms of business organization. In no case should it be inferred that the Economics Department, South Dakota State College, is recommending that farmers and investors follow this route in all instances. Other ways of organizing a cattle feeding business include individual proprietorships with ample credit, private corporations, vertical integration, and partnerships

James Hulless Oats

A new hulless oat, James, C.I. 5015, has been described. This variety was derived from the cross of ( Bond x Double Cross Bond) x Nakota. It is stiff-strawed, mid-early and has produced a high yield of good quality grain in eastern South Dakota. James has the White Russian type of stem rust resistance, Puccinia graminis avenae, Eriks, and Henn., and the Bond type leaf rust resistance, Puccinia coronata (Pers.) Cda. It is resistant to both species of smut, U stilago kolleri Wille. and Ustilago avenae (Pers.) Rostr

An Analysis of Small Grain Performance in South Dakota, 1942-1951

The small grain performance tests were located at the State Experiment Station, Brookings, the Central Substation, Highmore, the Range Field Station, Cottonwood and the North Central Substation, Eureka. In most cases the yields at the outlying stations were taken from nursery plots, with the exception of the winter wheat, rye and flax data which came from still strip plots of approximately 1/50th acre in size. The yields at Brookings were taken from drill trip plots 1/40th acre in size. Since yielding quality cannot be measured with absolute accuracy, small differences in yield are not important. Unless the difference exceeds the “least significant difference” given in the yield tables, little emphasis should be placed on the superiority in yield of one variety over another

Economic and Organizational Aspects of Cooperative Feedyards

During the past few years the cattle feeding industry in the United States has undergone many physical, technological changes. One of the most noticeable changes has been the growth of commercial and large-scale cattle feeding operations. Practically all of these beef factories are located on the west coast and other states in the southwest. States where most of the commercial and large-scale feeding is done include: California, Texas, Oklahoma, Kansas, Colorado, Arizona, and Nebraska. In California, for example, 68 per cent of the cattle on feed are fed in lots of over 10,000 head. There are a number of reasons why these areas are particularly well suited for large-scale feeding and they are: climate, extensive irrigation, and large supplies of low-cost feeder cattle. Another important reason is that there has been mass shifts of population to the coastal area creating a strong demand for meat products. Most of these commercial and large-scale feedyards are privately owned. Some of the larger ones are organized either as corporations or partnerships. Another type that is relatively new is the cooperative feedyard. As of January, 1960, there were only four such operations in the United States. C. G. Randell states that considerable interest has developed in cooperative feedyards in the past three years, especially in the west. Cooperative yards are located at Oklahoma City; Edwall, Washington; Pendleton, Oregon; and Bainville, Montana. Producer groups in many sections of the country have shown an interest, but according to Randell the principal deterrents are adequate capital and leadership. This study was made to serve as a guide for farmers and ranchers in the organization and operation of a cooperative feedyard. The specific objectives of this study are: (1) to determine the feasibility of a cooperative feedyard as a means of feeding cattle, and (2) to investigate the problems involved in the organization, operation, financing, and marketing of livestock from a cooperative feedyard. This study presents information relative to development of cooperative feedyards. Data and information used in this study were obtained by analyzing the organization and operation policies of various large—scale feeding operations and adapting these ideas to a cooperative type arrangement. Additional information was obtained by personal visits to various types of feedyards, making a case study of a cooperative feedyard, and drawing on actual experience with different types of feedyard operations. Costs and returns of a model cooperative feedlot are presented in this study by comparing the cost of feeding cattle in a cooperative feedyard as compared to feeding in a farm feedlot. Capital investment figures are presented to serve as a guide for interested groups planning to organize a cooperative feedyard. Capital requirements for the model feedyard developed in this study were obtained through the assistance of the Agricultural Engineering Department at South Dakota State College and the Economic Research Division of the Consumers Cooperative, Kansa City, Missouri. Since these data do not involve projected prices, they cannot provide the relationship of what is to be expected in years ahead; however, enough flexibility is provided in the plan so that price adjustments can be readily made

A primitive mantle source for the Neoarchean mafic rocks from the Tanzania Craton

Mafic rocks comprising tholeiitic pillow basalt, dolerite and minor gabbro form the basal stratigraphic unit in the ca. 2.8 to 2.6 Ga Geita Greenstone Belt situated in the NW Tanzania Craton. They outcrop mainly along the southern margin of the belt, and are at least 50 million years older than the supracrustal assemblages against which they have been juxtaposed. Geochemical analyses indicate that parts of the assemblage approach high Mg-tholeiite (more than 8 wt.% MgO). This suite of samples has a restricted compositional range suggesting derivation from a chemically homogenous reservoir. Trace element modeling suggests that the mafic rocks were derived by partial melting within the spinel peridotite field from a source rock with a primitive mantle composition. That is, trace elements maintain primitive mantle ratios (Zr/Hf = 32–35, Ti/Zr = 107–147), producing flat REE and HFSE profiles [(La/Yb)pm = 0.9–1.3], with abundances of 3–10 times primitive mantle and with minor negative anomalies of Nb [(Nb/La)pm = 0.6–0.8] and Th [(Th/La)pm = 0.6–0.9]. Initial isotope compositions (ɛNd) range from 1.6 to 2.9 at 2.8 Ga and plot below the depleted mantle line suggesting derivation from a more enriched source compared to present day MORB mantle. The trace element composition and Nd isotopic ratios are similar to the mafic rocks outcropping ∼50 km south. The mafic rocks outcropping in the Geita area were erupted through oceanic crust over a short time period, between ~2830 and ~2820 Ma; are compositionally homogenous, contain little to no associated terrigenous sediments, and their trace element composition and short emplacement time resemble oceanic plateau basalts. They have been interpreted to be derived from a plume head with a primitive mantle composition