CASH MARKET OR CONTRACT? HOW TECHNOLOGY AND CONSUMER DEMAND INFLUENCE THE DECISION

The use of contracts for producing and marketing agricultural commodities has become nearly universal in some sectors. Two factors are most frequently cited as being responsible for the use of agricultural contracts. The first, a demand-side factor, is the development of strong consumer preferences for specific qualities. The second, a supply-side factor, is technological change. In this paper, we use a principal agent framework to model how consumer demand and technology enter into a firm's decision to use contracts or the cash market.Demand and Price Analysis, Marketing,

Consumer Choice of Private Label or National Brand: The case of organic and non-organic milk

We use a two-stage, sample selection model to investigate organic milk purchases using Neilsen’s Homescan data. In the first stage, households decide on a weekly basis to buy mainly organic milk or non-organic milk. Results from this stage show that higher income, better education, having children at home, and several other demographic and marketing variables have a positive effect on organic choice. In the second stage, consumers then choose to buy mainly private label milk or national brand milk conditional on their first-stage choice. Most demographic and marketing variables are found to affect the organic and non-organic private label decision in the same way. However, our results show that a few factors, such as marriage status and children, affect the private label decision differently for organic and non-organic milk customers.organic milk, private label, sample selection, Agribusiness, Consumer/Household Economics, Demand and Price Analysis,

The 20th Century Transformation of U.S. Agriculture and Farm Policy

The structure of farms, farm households, and the rural communities in which they exist has evolved markedly over the last century. Historical data on a range of farm structure variables—including the value of agricultural production, commodity specialization, farming-dependent counties, and off-farm work—offer a perspective on the long-term forces that have helped shape the structure of agriculture and rural life over the past century. These forces include productivity growth, the increasing importance of national and global markets, and the rising influence of consumers on agricultural production. Within this long-term context of structural change, a review of some key developments in farm policy considers the extent to which farm policy design has or has not kept pace with the continuing transformation of American agriculture.farm policy, farm structure, policy adjustment, structural adjustment, mechanization, productivity growth, global markets, consumer stakeholders, price and income support, farm policy history, Agricultural and Food Policy, Farm Management,

Local Marketing of Organic Food by Certified Organic Processors, Manufacturers, and Distributors

Local organic food is garnering new interest. Using new data from a national survey of certified organic intermediaries, we examine local markets for organic food and assess which firms are likely to market locally. Approximately 25% of survey respondents primarily market their products locally, and 15% of the value of organic food (at the intermediate level) is sold locally. Larger firms are less likely to market locally, firms that handle a greater share of organic products are more likely to market locally, and the likelihood of marketing locally is lower the longer a firm has been certified organic.local food, local organic food, organic handlers, organic intermediaries, organic marketing, Agribusiness, Environmental Economics and Policy, Marketing,

Simulations of two-planet systems through all phases of stellar evolution: implications for the instability boundary and white dwarf pollution

Exoplanets have been observed at many stages of their host star's life, including the main sequence (MS), subgiant and red giant branch stages. Also, polluted white dwarfs (WDs) likely represent dynamically active systems at late times. Here, we perform 3-body simulations which include realistic post-MS stellar mass loss and span the entire lifetime of exosystems with two massive planets, from the endpoint of formation to several Gyr into the WD phase of the host star. We find that both MS and WD systems experience ejections and star-planet collisions (Lagrange instability) even if the planet-planet separation well-exceeds the analytical orbit-crossing (Hill instability) boundary. Consequently, MS-stable planets do not need to be closely-packed to experience instability during the WD phase. This instability may pollute the WD directly through collisions, or, more likely, indirectly through increased scattering of smaller bodies such as asteroids or comets. Our simulations show that this instability occurs predominately between tens of Myr to a few Gyrs of WD cooling.Comment: Accepted for publication in MNRAS; 24 pages, 19 figure

Segmented coronagraph design and analysis (SCDA): an initial design study of apodized vortex coronagraphs

The segmented coronagraph design and analysis (SCDA) study is a coordinated effort, led by Stuart Shaklan (JPL) and supported by NASA's Exoplanet Exploration Program (ExEP), to provide efficient coronagraph design concepts for exoplanet imaging with future segmented aperture space telescopes. This document serves as an update on the apodized vortex coronagraph designs devised by the Caltech/JPL SCDA team. Apodized vortex coronagraphs come in two flavors, where the apodization is achieved either by use of 1) a gray-scale semi-transparent pupil mask or 2) a pair of deformable mirrors in series. Each approach has attractive benefits. This document presents a comprehensive review of the former type. Future theoretical investigations will further explore the use of deformable mirrors for apodization.Comment: White Paper (2016-2017

An Open-Source 7-Axis, Robotic Platform to Enable Dexterous Procedures within CT Scanners

This paper describes the design, manufacture, and performance of a highly dexterous, low-profile, 7 Degree-of-Freedom (DOF) robotic arm for CT-guided percutaneous needle biopsy. Direct CT guidance allows physicians to localize tumours quickly; however, needle insertion is still performed by hand. This system is mounted to a fully active gantry superior to the patient's head and teleoperated by a radiologist. Unlike other similar robots, this robot's fully serial-link approach uses a unique combination of belt and cable drives for high-transparency and minimal-backlash, allowing for an expansive working area and numerous approach angles to targets all while maintaining a small in-bore cross-section of less than $16cm^2$. Simulations verified the system's expansive collision free work-space and ability to hit targets across the entire chest, as required for lung cancer biopsy. Targeting error is on average $<1mm$ on a teleoperated accuracy task, illustrating the system's sufficient accuracy to perform biopsy procedures. The system is designed for lung biopsies due to the large working volume that is required for reaching peripheral lung lesions, though, with its large working volume and small in-bore cross-sectional area, the robotic system is effectively a general-purpose CT-compatible manipulation device for percutaneous procedures. Finally, with the considerable development time undertaken in designing a precise and flexible-use system and with the desire to reduce the burden of other researchers in developing algorithms for image-guided surgery, this system provides open-access, and to the best of our knowledge, is the first open-hardware image-guided biopsy robot of its kind.Comment: 8 pages, 9 figures, final submission to IROS 201

Effects of CO2-induced pH reduction on the exoskeleton structure and biophotonic properties of the shrimp Lysmata californica.

The anticipated effects of CO2-induced ocean acidification on marine calcifiers are generally negative, and include dissolution of calcified elements and reduced calcification rates. Such negative effects are not typical of crustaceans for which comparatively little ocean acidification research has been conducted. Crustaceans, however, depend on their calcified exoskeleton for many critical functions. Here, we conducted a short-term study on a common caridean shrimp, Lysmata californica, to determine the effect of CO2-driven reduction in seawater pH on exoskeleton growth, structure, and mineralization and animal cryptic coloration. Shrimp exposed to ambient (7.99 ± 0.04) and reduced pH (7.53 ± 0.06) for 21 days showed no differences in exoskeleton growth (percent increase in carapace length), but the calcium weight percent of their cuticle increased significantly in reduced pH conditions, resulting in a greater Ca:Mg ratio. Cuticle thickness did not change, indicating an increase in the mineral to matrix ratio, which may have mechanical consequences for exoskeleton function. Furthermore, there was a 5-fold decrease in animal transparency, but no change in overall shrimp coloration (red). These results suggest that even short-term exposure to CO2-induced pH reduction can significantly affect exoskeleton mineralization and shrimp biophotonics, with potential impacts on crypsis, physical defense, and predator avoidance

Identifying and Measuring the Effect of Firm Clusters Among Certified Organic Processors and Handlers

This paper investigates the certified organic handler sector, a specialized component of the middle part of the farm-to-table marketing chain, and documents the impacts of firm agglomeration (or firm clusters) on firm-level performance or firm-level decisions. After accounting for endogeneity in firm clustering, our findings confirm that firm clusters have significant impacts, though the estimate of the impact depends on how a firm cluster is defined. For example, significant impacts on sales per employee range from an additional $0.17 million to$1.47 million, depending on whether a small or large number of firms is used as the minimum number to define a firm cluster.firm clusters, organic, treatment effects, Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development,