Crop Rotation

An extensive experiment in crop rotation has been under way at the South Dakota Experiment Station since 1897. This experiment was begun by Professor E.C. Chilcott, now of the Department of Agriculture at Washington, and was carried on continuously by him until the close of the last fiscal year. The writer has, however, been connected with the work as an assistant in the Department for six years. The field work has since its beginning been uninterruptedly in charge of Mr. William West, foreman of the Experiment Station farm. One bulletin, No. 79, which is now out of print, was published by Professor Chilcott in 1903, giving some of the results of the first five years of the experiment. It is perhaps needless to say that results from an experiment in crop rotation become increasingly more valuable the longer the experiment runs. It cannot be said, therefore, that the experiment is in any way finished, but it is believed that the importance of the work justifies the publication of results up to date. It is not the purpose in this bulletin to make an exhaustive study of all the results, or of all the different rotations. Such a task would be almost limitless. We will confine ourselves (1) To a brief discussion in a general way of the results from each rotation; (2) To a more extended study of the results from some of the shorter rotations, especially in regard to alternate cropping to wheat and corn, wheat and summer fallow, and wheat and a legume, vetch; (3) To the effect of applying manure with varying frequency to land that grows wheat alone, and to land in which corn enters into the rotation; (4) The effect of introducing a sod crop into the rotation, and (5) The influence of the immediately preceding crop upon the yield of wheat, oats and barley

Forage Plants and Cereals at the Highmore Sub-Station for 1904-5

The State Agricultural Experiment Station at Highmore, Hyde County, South Dakota, has been in operation for seven years of the location in testing and developing drouth [sic] resistant crops. Hyde County is fairly representative of a large portion of the state from the James River west, which is not well represented by the Brookings Station. The primary purpose of the Highmore Station was to test and develop grasses and forage crops, as it was supposed that this region would be largely a grass country instead of a farming country. Later developments have shown it desirable and in fact necessary to enlarge somewhat upon the work as it was first planned. Co-operative work with the United States Department of Agriculture in the testing of varieties of cereals has been carried on for three years. The report of this work as given by Mr. John S. Cole forms the latter part of this bulletin. The experimental farm at Highmore consists of 117 acres of land. The character of the soil and the lay of the land is somewhat poorer than the average in Hyde County. This, however, is not a disadvantage, for on this account no one can consider the records from the Highmore Station as coming from an unusually good piece of land and, therefore, unreliable for general comparisons

Report of Investigations at The Highmore Station for 1903

The work of testing grasses and other forage plants at Highmore during the season of 1903 was carried on by Mr. Sylvester Balz under the direction of Professor De Alton Saunders. The following report of the work has been prepared from the data furnished by Mr. Balz at the close of the season\u27s work. Professor Saunders severed his connection with the South Dakota Agricultural College in October, 1903. There being more land at the station than necessary to carry on the tests of forage plants, a part of it was used by Professor Chilcott and if Mr.Cole in testing macaroni wheats and other grains in co-operation with the United States Department of Agriculture. Their report forms the latter part of this bulletin

Local Charge Excesses in Metallic Alloys: a Local Field Coherent Potential Approximation Theory

Electronic structure calculations performed on very large supercells have shown that the local charge excesses in metallic alloys are related through simple linear relations to the local electrostatic field resulting from distribution of charges in the whole crystal. By including local external fields in the single site Coherent Potential Approximation theory, we develop a novel theoretical scheme in which the local charge excesses for random alloys can be obtained as the responses to local external fields. Our model maintains all the computational advantages of a single site theory but allows for full charge relaxation at the impurity sites. Through applications to CuPd and CuZn alloys, we find that, as a general rule, non linear charge rearrangements occur at the impurity site as a consequence of the complex phenomena related with the electronic screening of the external potential. This nothwithstanding, we observe that linear relations hold between charge excesses and external potentials, in quantitative agreement with the mentioned supercell calculations, and well beyond the limits of linearity for any other site property.Comment: 11 pages, 1 table, 7 figure

Cosmic acceleration from second order gauge gravity

We construct a phenomenological theory of gravitation based on a second order gauge formulation for the Lorentz group. The model presents a long-range modification for the gravitational field leading to a cosmological model provided with an accelerated expansion at recent times. We estimate the model parameters using observational data and verify that our estimative for the age of the Universe is of the same magnitude than the one predicted by the standard model. The transition from the decelerated expansion regime to the accelerated one occurs recently (at $\sim9.3\;Gyr$).Comment: RevTex4 15 pages, 1 figure. Accepted for publication in Astrophysics & Space Scienc

Evaluating the effects of climate change on US agricultural systems: sensitivity to regional impact and trade expansion scenarios

Agriculture is one of the sectors that is expected to be most significantly impacted by climate change. There has been considerable interest in assessing these impacts and many recent studies investigating agricultural impacts for individual countries and regions using an array of models. However, the great majority of existing studies explore impacts on a country or region of interest without explicitly accounting for impacts on the rest of the world. This approach can bias the results of impact assessments for agriculture given the importance of global trade in this sector. Due to potential impacts on relative competitiveness, international trade, global supply, and prices, the net impacts of climate change on the agricultural sector in each region depend not only on productivity impacts within that region, but on how climate change impacts agricultural productivity throughout the world. In this study, we apply a global model of agriculture and forestry to evaluate climate change impacts on US agriculture with and without accounting for climate change impacts in the rest of the world. In addition, we examine scenarios where trade is expanded to explore the implications for regional allocation of production, trade volumes, and prices. To our knowledge, this is one of the only attempts to explicitly quantify the relative importance of accounting for global climate change when conducting regional assessments of climate change impacts. The results of our analyses reveal substantial differences in estimated impacts on the US agricultural sector when accounting for global impacts vs. US-only impacts, particularly for commodities where the United States has a smaller share of global production. In addition, we find that freer trade can play an important role in helping to buffer regional productivity shocks

Chlamydia trachomatis Seroprevalence and Ultrasound-Diagnosed Uterine Fibroids in a Large Population of Young African-American Women

Reproductive tract infections have long been hypothesized to increase the risk of uterine fibroids. Few studies have been conducted, even for the common infection genital Chlamydia trachomatis (gCT), and only with self-reported gCT data. Our investigation used micro-immunofluorescence serology for gCT to characterize past exposure. We used cross-sectional enrollment data from a prospective fibroid study carried out in the Detroit, Michigan, area; ultrasound examinations systematically screened for fibroids. Participants were African-American women aged 23–34 years (recruited in 2010–2012). Age- and multivariable-adjusted logistic regression models were used to estimate odds ratios. A total of 1,587 women (94% of participants) had unequivocal gCT serology results; 22% had fibroids. Those who were seropositive for gCT were less likely to have fibroids (age-adjusted odds ratio = 0.68, 95% confidence interval: 0.54, 0.87; multivariable-adjusted odds ratio = 0.80, 95% confidence interval: 0.62, 1.03). Inverse associations were similar across categories of fibroid size, number, and total volume. Participant groups likely to have had multiple or severe infections (multiple serovar groups, more sex partners, clinically diagnosed chlamydia) all showed statistically significantly reduced odds of fibroids. A protective association of gCT with fibroids was unexpected but plausible. gCT infection might increase immune surveillance and eliminate early lesions. Further investigation on the relationship between fibroid development and reproductive tract infections is neede

Inverse Probability Weights for the Analysis of Polytomous Outcomes

Polytomous outcomes are common in epidemiologic studies. Analyses based on multinomial models employ a likelihood that utilizes the data observed in all outcome categories simultaneously and permits inferences regarding associations across outcome categories. However, the potentially large number of estimated parameters produced by multinomial model fitting can lead to problems of estimation and inference (1). We have proposed an inverse-probability-of-exposure weighted multinomial model for analysis of polytomous outcomes, described its implementation, and illustrated it. The approach yields marginal estimates of associations, which are sometimes desirable as summary measures of association (2). This approach allows for confounding control and tends to be less susceptible to problems of estimation that arise when at least one outcome category is rare

A cosmological concordance model with dynamical vacuum term

We demonstrate that creation of dark-matter particles at a constant rate implies the existence of a cosmological term that decays linearly with the Hubble rate. We discuss the cosmological model that arises in this context and test it against observations of the first acoustic peak in the cosmic microwave background (CMB) anisotropy spectrum, the Hubble diagram for supernovas of type Ia (SNIa), the distance scale of baryonic acoustic oscillations (BAO) and the distribution of large scale structures (LSS). We show that a good concordance is obtained, albeit with a higher value of the present matter abundance than in the \Lambda CDM model. We also comment on general features of the CMB anisotropy spectrum and on the cosmic coincidence problem.Comment: Revised version. Accepted for publication in Physics Letters

The structure of oppositionality: Response disposition and situational aspects

Background: The Amsterdam Scale of Oppositionality (ASO) is a recently developed self-report instrument to measure the full range of oppositionality. It was used to test the assumption that oppositionality can best be conceptualized as a combination of emotions and behaviors varying across contexts, i.e., with parents, peers and authority figures. Method: The sample consisted of 560 boys and 598 girls, aged 8 to 12 years. The thirty items of the ASO, grouped in item parcels, were analyzed using confirmatory factor analyses. Results: Results confirmed the main hypothesis. The best fitting models contained strongly related emotional and behavioral factors and three mutually related situational factors. Oppositionality appeared to be to a large extent situation-specific. Girls are more affected by the situation than boys and show less oppositionality only outside the family context. Conclusions: Results are discussed with respect to the concept of oppositionality, varying expectations for interpersonal consequences, and implications for clinical assessment and studies of inter-informant reliability