THE ECONOMIC IMPACTS OF ALTERNATIVE MANURE MANAGEMENT REGULATIONS ON HOG FARMS IN THE HEARTLAND: AN INDIVIDUAL-FARM ANALYSIS

A whole-farm modeling approach applied to survey data was used to assess the economic impacts on Heartland hog farms of alternative manure management regulations on manure application. Results showed differential economic impacts on the hog operations. Many large farms (over 2,500 hogs) had to lease additional land to meet restrictions on manure phosphorous application, with reductions in net crop returns exceeding those of medium size operations (750-2,500 hogs). Feeding hogs a phytase diet to lessen phosphorous in manure reduced the additional land needed and moderated the increase in manure application costs, but net crop returns still dropped for most operations.Livestock Production/Industries,

Doctor of Philosophy

dissertationWireless communication has become an essential part of everyday life. The hunger for more data, more phone calls, more video, and more access in more places, including vehicles, is growing massively. Communication in vehicles is particularly challenging because of their extremely high multipath environment. In addition, there is significant interest in reducing the number of wires in vehicles to reduce weight, complexity, maintenance, etc. and replace them with wireless systems. Preliminary research shows that MIMO systems take advantage of the extreme multipath environment found in aircraft and other vehicles and also provides more consistent channel capacity than SISO systems. The purpose of this research was to quantify complex channels (including the aircraft/vehicle environment) and their relation to other environments, evaluate MIMO in aircraft, provide design constraints for accurately modeling complex channels, and provide information to predict optimum antenna type and location to enable communication in aircraft/cars/buses/ships/trains/etc. and other extreme channels. The ability to evaluate and design MIMO technologies from the guidelines in this paper is potentially transformative for aircraft safety - enabling a new generation of location specific monitoring and maintenance. Average measured capacity was found to be between 18 and 21 bits/s/Hz using a 4x4 array of antennas, and had no direct relation to the size of the channel. Site-specific capacity showed a multipath rich channel, varying between 15 to 23 bits/s/Hz. The capacity decreased for increasing measurement distance, with exceptions near reflective objects that increase multipath. Due to these special circumstances for site-specific locations within complex channels, it is recommended that 3D ray tracing be used for modeling as it is more accurate than commonly used statistical models, within 1.1 bits/s/Hz. This showed that our 3D ray tracing is adaptable to various environments and gives a more accurate depiction than statistical models that average channel variations. This comes at the cost of greater model complexity. If increased complexity is not desirable, Nakagami 1.4 could be used as the next most accurate model. Design requirements for modeling different complex channels involve a detailed depiction of channel geometry, including height, width, length, shape (square, cylindrical, slanted walls, etc.), large windows, and reflective objects inside the channel space, especially those near the transmitter. Overall, the multipath rich channel found in vehicles is an excellent environment for MIMO systems. These complex channels can be simulated accurately without measurement and before they are even built using our sitespecific 3D ray tracing software combined with a detailed signal model to incorporate antenna effects

3D ray-tracing for intra-vehicle environments

Journal ArticleIn order to develop a wireless communication system that could be used for all types of aircraft sensor networks, the severe multipath channel found inside aircrafts must be well defined. This multipath channel is much more complex than usual outdoor/indoor channels and thus far, research has been limited to a basic stochastic model for the aircraft environment called hyper-Rayleigh [3]. This model has been useful for a general understanding of the aircraft environment; however, in preliminary simulations this model was not accurate enough to describe MIMO performance for a range of fading channels [7]. The next level of accuracy in modeling is site-specific modeling, also known as ray-tracing. Due to the 3-dimensional (3D) reflective surface of the fuselage, ray-tracing must be implemented in a 3D simulation in order to fully describe the aircraft environment

Single-channel kinetics of BK (Slo1) channels

Single-channel kinetics has proven a powerful tool to reveal information about the gating mechanisms that control the opening and closing of ion channels. This introductory review focuses on the gating of large conductance Ca2+- and voltage-activated K+ (BK or Slo1) channels at the single-channel level. It starts with single-channel current records and progresses to presentation and analysis of single-channel data and the development of gating mechanisms in terms of discrete state Markov (DSM) models). The DSM models are formulated in terms of the tetrameric modular structure of BK channels, consisting of a central transmembrane pore-gate domain (PGD) attached to four surrounding transmembrane voltage sensing domains (VSD) and a large intracellular cytosolic domain (CTD), also referred to as the gating ring. The modular structure and data analysis shows that the Ca2+ and voltage dependent gating considered separately can each be approximated by 10-state two-tiered models with 5 closed states on the upper tier and 5 open states on the lower tier. The modular structure and joint Ca2+ and voltage dependent gating are consistent with a 50 state two-tiered model with 25 closed states on the upper tier and 25 open states on the lower tier. Adding an additional tier of brief closed (flicker states) to the 10-state or 50-state models improved the description of the gating. For fixed experimental conditions a channel would gate in only a subset of the potential number of states. The detected number of states and the correlations between adjacent interval durations are consistent with the tiered models. The examined models can account for the single-channel kinetics and the bursting behavior of gating. Ca2+ and voltage activate BK channels by predominantly increasing the effective opening rate of the channel with a smaller decrease in the effective closing rate. Ca2+ and depolarization thus activate by mainly destabilizing the closed states

Predicted MIMO performance in intra-vehicle channels

Journal ArticleWireless sensor networks inside vehicles face particularly harsh multipath and shadowing constraints. The closed or semi-closed metallic structure functions much like a reverberation chamber, but with some regions shielded from other regions. Vehicles (particularly aircraft) often have extremely high electromagnetic interference across reverberates within the shell of the vehicle, creating a strong multipath noise environment. This poses unique challenges and unique opportunities

Lab report writing (and teaching!) made easy

Journal ArticleThis paper reports on a project to improve students' ability to write better lab reports and assist teaching assistants (TAs) in grading reports in a consistent manner. A lab report teaching system was developed that includes lab report templates, teaching assistant instructions, grading rubrics, examples, peer review materials and instructions, and recommendations for quickly providing student feedback (grading). These materials were developed for project-based labs across the electrical engineering curriculum and utilize methods to write weekly lab updates that are combined into a final lab report, mimicking methods commonly used in industry. The technical writing information was adapted to all levels of complexity to help students from freshman through senior years. The system begins with instruction on writing very basic reports, and builds each year on previous knowledge and practices, to prepare students to later write complex reports. This system is designed to improve students' understanding of labs (by ‘writing to learn') in addition to preparing them for the communication intensive workplace. The amount of time spent grading such reports is often a primary concern, as this is commonly given as a reason for not requiring advanced writing assignments in engineering classes. Detailed guidelines and grading rubrics are included in this manual to instruct TAs on better and more consistent grading techniques. Guidelines for checking both lab books and formal lab reports help improve TA training and grading consistency, reducing student complaints. Although this system was designed for an electrical engineering program, it can also be adapted to other technical fields and used for various scientific lab reports