'Organic' and 'Conventional' Grain and Soybean Prices in the Northern Great Plains and Upper Midwest: 1995 through 2003

As part of the sustainable agriculture research program in the Economics Department at South Dakota State University (SDSU), ‘organic’ and ‘conventional’ crop prices have been compared for nearly a decade. This pamphlet serves as an update of price comparisons through 2003 and a final conclusion of the price series comparison, which we will no longer continue. The pamphlet also contains brief reference to another source of organic price data (see the appendix). The information in this pamphlet should be of use to farmers and others considering management changes and investments related to organic agriculture, as well as to policy makers.organic foods, food prices, soybean, grain

Potential for the Conservation Security Program to Induce More Ecologically Diverse Crop Rotations in the Western Corn Belt

The potential of the USDA’s new Conservation Security Program (CSP) for inducing farmers to adopt more ecologically diverse crop rotations in the Western Corn Belt is examined. Simulations are conducted for a representative farm model in southeastern South Dakota, using different assumptions about commodity policies and CSP payments.CRP, Conservation, crop rotation, crop diversity

Comparison of \u27Organic\u27 and \u27Conventional\u27 Grains and Soybean Prices in the Northern Great Plains and Upper MIdwest: 1995 through 2003

Price premiums for organic crops drew the attention of an increasing number of farmers throughout the 1990s. Premiums contributed to the expansion of U.S. farmland managed under organic farming systems during that time period. Expansion of organic farming systems continued at least through 2001. According to the U.S. Department of Agriculture (USDA) Economic Research Service\u27s most recent data on organic farming systems, U.S. farmers and ranchers added almost one million acres of certified organic farmland between 1997 and 2001, an increase of 74 percent. Over that same time frame, certified organic cropland increased by 53 percent). The USDA implemented national organic standards for organic production and processing in October 2002, which could facilitate further growth in the organic farming sector. As part of the sustainable agriculture research program in the Economics Department at South Dakota State University (SDSU), \u27organic\u27 and \u27conventional\u27 crop prices have been compared for nearly a decade. This pamphlet serves as an update of price comparisons through 2003 and a final conclusion of the price series comparison, which we will no longer continue. The pamphlet also contains brief reference to another source of organic price data (see the appendix). The information in this pamphlet should be of use to farmers and others considering management changes and investments related to organic agriculture, as well as to policy makers

Potential Use of the Conservation Security Program to Encourage Diverse Crop Rotations in Eastern South Dakota

A central concern in many discussions of ecological sustainability in agricultural regions of the U.S. Midwest and Great Plains is that of crop system diversity. Many factors have contributed to the loss of crop system diversity over that last half-century (Dumke and Dobbs), one of which is public policy. The U.S. Farm Security and Rural Investment Act of 2002 (\u272002 Farm Bill\u27) provided for a new agri-environmental program that could have potential to help restore some of the crop system diversity that has been lost. The Conservation Security Program (CSP) is that program. This report, drawn from a Master of Science in Economics thesis by one of us (Streff), contains results of an examination of the CSP\u27s potential to help induce more crop system diversity in southeastern South Dakota (SD)

The role of previous generations of stars in triggering star formation and driving gas dynamics

We present hydrodynamic and magnetohydrodynamic (MHD) simulations of sub galactic regions including photoionising and supernova feedack. We aim to improve the initial conditions of our region extraction models by including an initial population of stars. We also investigate the reliability of extracting regions in simulations, and show that with a good choice of region, results are comparable with using a larger region for the duration of our simulations. Simulations of star formation on molecular cloud scales typically start with a turbulent cloud of gas, from which stars form and then undergo feedback. In reality, a typical cloud or region within a galaxy may already include, or reside near some population of stars containing massive stars undergoing feedback. We find the main role of a prior population is triggering star formation, and contributing to gas dynamics. Early time supernova from the initial population are important in triggering new star formation and driving gas motions on larger scales above 100 pc, whilst the ionising feedback contribution from the initial population has less impact, since many members of the initial population have cleared out gas around them in the prior model. In terms of overall star formation rates though, the initial population has a relatively small effect, and the feedback does not for example suppress subsequent star formation. We find that MHD has a relatively larger impact than initial conditions, reducing the star formation rate by a factor of 3 at later times.Comment: 12 pages, 10 figure

Time-Dependent Physicochemical Changes of Carbonate Surfaces from SmartWater (Diluted Seawater) Flooding Processes for Improved Oil Recovery.

Over the past few decades, field- and laboratory-scale studies have shown enhancements in oil recovery when reservoirs, which contain high-salinity formation water (FW), are waterflooded with modified-salinity salt water (widely referred to as the low-salinity, dilution, or SmartWater effect for improved oil recovery). In this study, we investigated the time dependence of the physicochemical processes that occur during diluted seawater (i.e., SmartWater) waterflooding processes of specific relevance to carbonate oil reservoirs. We measured the changes to oil/water/rock wettability, surface roughness, and surface chemical composition during SmartWater flooding using 10-fold-diluted seawater under mimicked oil reservoir conditions with calcite and carbonate reservoir rocks. Distinct effects due to SmartWater flooding were observed and found to occur on two different timescales: (1) a rapid (<15 min) increase in the colloidal electrostatic double-layer repulsion between the rock and oil across the SmartWater, leading to a decreased oil/water/rock adhesion energy and thus increased water wetness and (2) slower (>12 h to complete) physicochemical changes of the calcite and carbonate reservoir rock surfaces, including surface roughening via the dissolution of rock and the reprecipitation of dissolved carbonate species after exchanging key ions (Ca2+, Mg2+, CO32-, and SO42- in carbonates) with those in the flooding SmartWater. Our experiments using crude oil from a carbonate reservoir reveal that these reservoir rock surfaces are covered with organic-ionic preadsorbed films (ad-layers), which the SmartWater removes (detaches) as flakes. Removal of the organic-ionic ad-layers by SmartWater flooding enhances oil release from the surfaces, which was found to be critical to increasing the water wetness and significantly improving oil removal from carbonates. Additionally, the increase in water wetness is further enhanced by roughening of the rock surfaces, which decreases the effective contact (interaction) area between the oil and rock interfaces. Furthermore, we found that the rate of these slower physicochemical changes to the carbonate rock surfaces increases with increasing temperature (at least up to an experimental temperature of 75 °C). Our results suggest that the effectiveness of improved oil recovery from SmartWater flooding depends strongly on the formation of the organic-ionic ad-layers. In oil reservoirs where the ad-layer is fully developed and robust, injecting SmartWater would lead to significant removal of the ad-layer and improved oil recovery

The effects of rural and urban areas on time allocated in self-employment : differences between men and women

This study investigates the association of the rural−urban divide and the time individuals allocate in self-employment. The empirical analysis uses fixed effects modelling on data from the UK Household Longitudinal Survey over the period 2009−2019. The study identifies significant differences in the time men and women allocate in self-employment between rural and urban areas according to their career age group. While men and women tend to allocate more time in self-employment in their senior career age when residents of urban areas, the time they allocate in self-employment between rural and urban areas in early- and mid-career age differs markedly. More importantly, we find that significant differences exist not only between residents of rural and urban areas, but also between residents of these areas and in-migrants to these areas. We find a significant positive effect on the time senior career age women who migrate to rural areas allocate in self-employment. In contrast, we find that early career men who move from rural to urban areas allocate significantly more time in self-employment. The results reveal the existence of complex dynamics between gender and age, which affect the allocation of time in self-employment between rural and urban areas

CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, $r$, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for $r > 0.003$ at greater than $5\sigma$, or, in the absence of a detection, of reaching an upper limit of $r < 0.001$ at $95\%$ CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note: text overlap with arXiv:1907.0447