Identifying Advantages and Disadvantages of Variable Rate Irrigation – An Updated Review

Variable rate irrigation (VRI) sprinklers on mechanical move irrigation systems (center pivot or lateral move) have been commercially available since 2004. Although the number of VRI, zone or individual sprinkler, systems adopted to date is lower than expected there is a continued interest to harness this technology, especially when climate variability, regulatory nutrient management, water conservation policies, and declining water for agriculture compound the challenges involved for irrigated crop production. This article reviews the potential advantages and potential disadvantages of VRI technology for moving sprinklers, provides updated examples on such aspects, suggests a protocol for designing and implementing VRI technology and reports on the recent advancements. The advantages of VRI technology are demonstrated in the areas of agronomic improvement, greater economic returns, environmental protection and risk management, while the main drawbacks to VRI technology include the complexity to successfully implement the technology and the lack of evidence that it assures better performance in net profit or water savings. Although advances have been made in VRI technologies, its penetration into the market will continue to depend on tangible and perceived benefits by producers

The two social philosophies of Ostroms' institutionalism

The article argues that Ostroms’ institutionalism has a dimension that is complex and profound enough to deserve to be considered a “social theory” or a “social philosophy”. The paper pivots around the thesis that the “social philosophy” behind the Bloomington School’s research agenda has in fact two facets that may or may not be consistent with each other. The article describes the main features of the two facets, offers a brief overview of the development of these ideas, and clarifies their relationship to Public Choice theory and alternative visions of public goods analysis, public administration, and governance. The argument goes further to raise the provocative question whether the two “social philosophies” involved in the approach undertaken by Elinor Ostrom and Vincent Ostrom are necessarily and inseparably connected with the rest of their research program.Institutional Theory; Polycentricity; Governance; Public choice; Institutional Design; Social Theory

Aging and the Welfare State: The Role of Young and Old Voting Pivots

An income tax is generally levied on both capital and labor income. The working young bears mostly the burden of the tax on labor income, whereas the retired old, who already acummulated her savings, bears the brunt of the capital income tax. Therefore, there arise two types of conflict in the determination of the income tax: the standard intragenerational conflict between the poor and the rich, and an ntergenerational conflict between the young and the old. The paper studies how aging affects the resolution of these conflicts, and the politico-economic forces that are at play: the changes in the voting pivots and the fiscal leakage from tax payers to transfer recipients.

Stochastic Database Cracking: Towards Robust Adaptive Indexing in Main-Memory Column-Stores

Modern business applications and scientific databases call for inherently dynamic data storage environments. Such environments are characterized by two challenging features: (a) they have little idle system time to devote on physical design; and (b) there is little, if any, a priori workload knowledge, while the query and data workload keeps changing dynamically. In such environments, traditional approaches to index building and maintenance cannot apply. Database cracking has been proposed as a solution that allows on-the-fly physical data reorganization, as a collateral effect of query processing. Cracking aims to continuously and automatically adapt indexes to the workload at hand, without human intervention. Indexes are built incrementally, adaptively, and on demand. Nevertheless, as we show, existing adaptive indexing methods fail to deliver workload-robustness; they perform much better with random workloads than with others. This frailty derives from the inelasticity with which these approaches interpret each query as a hint on how data should be stored. Current cracking schemes blindly reorganize the data within each query's range, even if that results into successive expensive operations with minimal indexing benefit. In this paper, we introduce stochastic cracking, a significantly more resilient approach to adaptive indexing. Stochastic cracking also uses each query as a hint on how to reorganize data, but not blindly so; it gains resilience and avoids performance bottlenecks by deliberately applying certain arbitrary choices in its decision-making. Thereby, we bring adaptive indexing forward to a mature formulation that confers the workload-robustness previous approaches lacked. Our extensive experimental study verifies that stochastic cracking maintains the desired properties of original database cracking while at the same time it performs well with diverse realistic workloads.Comment: VLDB201

Design, fabrication and test of a 4750 Newton-meter-second double Gimbal control moment gyroscope

The development of a prototype Control Moment Gyroscope (CMG) is discussed. Physical characteristics and the results of functional testing are presented to demonstrate the level of system performance obtained. Particular attention is given to how the man-rated mission requirement influenced the choice of the materials, fabrication, and design details employed. Comparisons are made of the measured system responses against the prediction generated by computer simulation

On Keynes's Theory of the Aggregate Price Level in the Treatise: Any Help for Modern Aggregate Analysis?

The paper explores the theory of the aggregate price and profit in Keynes's Treatise for its implications for modern macroeconomic analysis. Here profits are defined in terms of aggregate investment and saving. Deriving aggregate total revenue and aggregate total cost from this price theory, the paper shows how to construct a version of the Keynesian cross diagram. It then examines an IS-LM model from the perspective of the Treatise's price theory, focusing on an interpretation of the business cycle in which savings and investment may not equal. Comparing the Treatise's price theory with a neoclassical definition of profit, the paper reconstructs the cross diagram and reconsiders a related IS-LM model, with a focus on fiscal policy. This clarifies how microfoundations affect the standard cross and IS model. Further, the reconstructed cross diagram allows for derivation of neoclassical aggregate supply, to which the derivation of neoclassical aggregate demand can be added. Comparative statics of this AS-AD analysis suggests that a focus on profit might be useful in identifying the manifestation of exogenous technology shocks of real business cycle theory.Aggregate Price Level, Keynes

Large-diameter astromast development

The 15-m-long by 0.75-diameter deployable supermast was delivered. The performance characteristics, design parameters, and developmental work associated with this mast are described. The main differences, besides the length of these two mast sections, are a change in the longeron material (the principal structural member) to a circular cross section and the incorporation of a lanyard-bridle system which makes unaided deployment and retraction possible in zero gravity

There's Something Happening Here: A Look at The California Endowment's Building Healthy Communities Initiative

In 2011, TCE commissioned PERE to help capture some of the dynamism happening in each of the sites as they were pivoting from the initial planning phase, which started in 2009, to early implementation.Our focus was on the over-arching story of BHC rather than on the narrative of each site, which would have required many more interviews, many more site visits, and many, many more pages to convey. And while we touch on some of the interactions between BHC and the communications and policy work done under the statewide umbrella of Health Happens Here, our emphasis in this report is on BHC and the sites themselves.Through the course of this research, we have become increasingly convinced that TCE is indeed onto something -- if not big, at least important. In order to clarify exactly what it is, we use a simplifying three-part storyline linked together by an overarching concept of Just Health

Automatic Romaine Heart Harvester

The Romaine Robotics Senior Design Team developed a romaine lettuce heart trimming system in partnership with a Salinas farm to address a growing labor shortage in the agricultural industry that is resulting in crops rotting in the field before they could be harvested. An automated trimmer can alleviate the most time consuming step in the cut-trim-bag harvesting process, increasing the yields of robotic cutters or the speed of existing laborer teams. Leveraging the Partner Farm’s existing trimmer architecture, which consists of a laborer loading lettuce into sprungloaded grippers that are rotated through vision and cutting systems by an indexer, the team redesigned geometry to improve the loading, gripping, and ejection stages of the system. Physical testing, hand calculations, and FEA were performed to understand acceptable grip strengths and cup design, and several wooden mockups were built to explore a new actuating linkage design for the indexer. The team manufactured, assembled, and performed verification testing on a full-size metal motorized prototype that can be incorporated with the Partner Farm’s existing cutting and vision systems. The prototype met all of the established requirements, and the farm has implemented the redesign onto their trimmer. Future work would include designing and implementing vision and cutting systems for the team’s metal prototype