Whole Farm Nutrient Balance Under Different Grazing Systems: Project Overview

The amount of phosphorus (P) in surface runoff from agricultural lands is of concern because of the potential for eutrophication of Iowa’s waterways. Currently, there is limited information about the total P loads in surface runoff coming from pastureland in the Midwest. Much of the P runoff is likely associated with sediment. Because foliage limits soil disruption caused by the impact of raindrops and because forage roots hold soil particles, forages harvested at an appropriate height, through suitable grazing management, should maintain water infiltration and minimize sediment and P loss in surface runoff from pastures. Grazing management may influence utilization of P by the animal, by impacting P digestibility. The objective of this project is to quantify P flows through systems operated under different grazing management practices. Figure 1 illustrates P inputs and outputs in the grazing system

Evolved Open-Endedness in Cultural Evolution: A New Dimension in Open-Ended Evolution Research

The goal of Artificial Life research, as articulated by Chris Langton, is "to contribute to theoretical biology by locating life-as-we-know-it within the larger picture of life-as-it-could-be" (1989, p.1). The study and pursuit of open-ended evolution in artificial evolutionary systems exemplifies this goal. However, open-ended evolution research is hampered by two fundamental issues; the struggle to replicate open-endedness in an artificial evolutionary system, and the fact that we only have one system (genetic evolution) from which to draw inspiration. Here we argue that cultural evolution should be seen not only as another real-world example of an open-ended evolutionary system, but that the unique qualities seen in cultural evolution provide us with a new perspective from which we can assess the fundamental properties of, and ask new questions about, open-ended evolutionary systems, especially in regard to evolved open-endedness and transitions from bounded to unbounded evolution. Here we provide an overview of culture as an evolutionary system, highlight the interesting case of human cultural evolution as an open-ended evolutionary system, and contextualise cultural evolution under the framework of (evolved) open-ended evolution. We go on to provide a set of new questions that can be asked once we consider cultural evolution within the framework of open-ended evolution, and introduce new insights that we may be able to gain about evolved open-endedness as a result of asking these questions.Comment: 26 pages, 1 figure, 1 table, submitted to Artificial Life journal (special issue on Open-Ended Evolution

Loss of KLP-19 polar ejection force causes misorientation and missegregation of holocentric chromosomes

Holocentric chromosomes assemble kinetochores along their length instead of at a focused spot. The elongated expanse of an individual holocentric kinetochore and its potential flexibility heighten the risk of stable attachment to microtubules from both poles of the mitotic spindle (merotelic attachment), and hence aberrant segregation of chromosomes. Little is known about the mechanisms that holocentric species have evolved to avoid this type of error. Our studies of the influence of KLP-19, an essential microtubule motor, on the behavior of holocentric Caenorhabditis elegans chromosomes suggest that it has a major role in combating merotelic attachments. Depletion of KLP-19, which associates with nonkinetochore chromatin, allows aberrant poleward chromosome motion during prometaphase, misalignment of holocentric kinetochores, and multiple anaphase chromosome bridges in all mitotic divisions. Time-lapse movies of GFP-labeled mono- and bipolar spindles demonstrate that KLP-19 generates a force on relatively stiff holocentric chromosomes that pushes them away from poles. We hypothesize that this polar ejection force minimizes merotelic misattachment by maintaining a constant tension on pole–kinetochore connections throughout prometaphase, tension that compels sister kinetochores to face directly toward opposite poles

COMPARING MEASURING METHODS USING THE SENSITIVITY RATIO: AN APPLICATION TO RESISTANCE SCREENING IN SOYBEANS

When there are several methods of measuring a physical or chemical property, it is necessary to determine which method is best. If both methods are measured on the same scale, the most precise method will be preferred. However, often the methods have different scales. The sensitivity ratio allows for explicit comparison of methods with different scales. We use the sensitivity ratio to compare soybean resistance screening methods to evaluate the resistance of soybean varieties to Sclerotinia sclerotiorum. When compared to the root mean square error or the coefficient of variation, the sensitivity ratio can order methods differently both when the methods are measured on different scales and on the same scale. Our results cast doubt upon using standard precision statistics such as the root mean square error or the coefficient of variation to compare measuring methods and we suggest that the sensitivity ratio should be used instead

A Neurotoxic Phosphoform of Elk-1 Associates with Inclusions from Multiple Neurodegenerative Diseases

Neurodegenerative diseases are characterized by a number of features including the formation of inclusions, early synaptic degeneration and the selective loss of neurons. Molecules serving as links between these shared features have yet to be identified. Identifying candidates within the diseased microenvironment will open up novel avenues for therapeutic intervention. The transcription factor Elk-1 resides within multiple brain areas both in nuclear and extranuclear neuronal compartments. Interestingly, its de novo expression within a single dendrite initiates neuronal death. Given this novel regionalized function, we assessed whether extranuclear Elk-1 and/or phospho-Elk-1 (pElk-1) protein might be associated with a spectrum of human neurodegenerative disease cases including Lewy body Disease (e.g. Parkinson's), Alzheimer's disease, and Huntington's Disease. We first determined the importance of Elk-1 post-translational modifications on its ability to initiate regionalized cell death. We next screened human cases from three major neurodegenerative diseases to look for remarkable levels of Elk-1 and/or pElk-1 protein as well as their association with inclusions characteristic of these diseases. We compared our findings to age-matched control cases. We find that the ability of Elk-1 to initiate regionalized neuronal death depends on a specific phosphosite, T417. Furthermore, we find that T417+ Elk-1 uniquely associates with several types of inclusions present in cases of human Lewy body Disease, Alzheimer's disease, and Huntington's Disease. These results suggest a molecular link between the presence of inclusions and neuronal loss that is shared across a spectrum of neurodegenerative disease

Promoting Social Behaviour in Reducing Peak Electricity Consumption Using Multi-Agent Systems

As we move towards an energy system based on renewable energy sources, we need to consider their inflexibility to meet sudden peaks in demand. It is therefore important to reduce the peak load placed on our energy system. For individual households this means spreading out the use of high-powered appliances, such as dishwashers and washing machines, throughout the day. Traditional approaches to this problem have relied on differential pricing set by a centralised utility company, but this mechanism has not been effective in promoting widespread shifting of appliance usage. Our previous research investigated a decentralised mechanism where agents receive an initial allocation of time-slots to use their appliances, which they can then exchange with other agents. This was found to be an effective approach to reducing the peak load within a community energy system when we introduced social capital, the tracking of favours given and received, in order to incentivise agents to act flexibly by accepting exchanges that do not immediately benefit them. This system encouraged self-interested agents to learn socially beneficial behaviour in order to earn social capital that they could later use to improve their own performance. In this paper we expand this work by implementing real world household appliance usage data in order to ensure that our mechanism could adapt to the challenging demand needs of real households. We also demonstrate how smaller and more diverse populations can optimise more effectively than larger community energy systems and better overcome the challenges of real-world demand peaks

Impacts of Beef Cattle–Grazing Systems on Cattle Distribution and Streambank Erosion

Many of Iowa’s surface waters contain high sediment and phosphorus(P) concentrations. It is recognized that overgrazing along pasture streams may result in soil erosion and manure deposition that contribute to P loading of pasture streams. Little research has evaluated the effects of grazing management on sediment and P loading of pasture streams in the Midwest, but grazing management is still generally considered to limit sediment and P loading of pasture streams. The objective of this study was to measure the effects of beef cattle– grazing systems on the spatial and temporal distribution patterns of cattle, the resulting impacts on selected pasture characteristics, and streambank erosion from pasture streams

Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective

This Report has a number of inter-related general purposes. One is to explore the extent to which food, nutrition, physical activity, and body composition modify the risk of cancer, and to specify which factors are most important. To the extent that environmental factors such as food, nutrition, and physical activity influence the risk of cancer, it is a preventable disease. The Report specifies recommendations based on solid evidence which, when followed, will be expected to reduce the incidence of cancer

Engineering Analysis Studies for Preliminary Design of Lightweight Cryogenic Hydrogen Tanks in UAV Applications

A series of engineering analysis studies were conducted to investigate the potential application of nanoclay-enhanced graphite/epoxy composites and polymer cross-linked silica aerogels in cryogenic hydrogen storage tank designs. This assessment focused on the application of these materials in spherical tank designs for unmanned aeronautic vehicles with mission durations of 14 days. Two cryogenic hydrogen tank design concepts were considered: a vacuum-jacketed design and a sandwiched construction with an aerogel insulating core. Analyses included thermal and structural analyses of the tank designs as well as an analysis of hydrogen diffusion to specify the material permeability requirements. The analyses also provided material property targets for the continued development of cross-linked aerogels and nanoclay-enhanced graphite/epoxy composites for cryogenic storage tank applications. The results reveal that a sandwiched construction with an aerogel core is not a viable design solution for a 14-day mission. A vacuum-jacketed design approach was shown to be far superior to an aerogel. Aerogel insulation may be feasible for shorter duration missions. The results also reveal that the application of nanoclay-enhanced graphite/epoxy should be limited to the construction of outer tanks in a vacuum-jacketed design, since a graphite/epoxy inner tank does not provide a significant weight savings over aluminum and since the ability of nanoclay-enhanced graphite/epoxy to limit hydrogen permeation is still in question