Is Growing Livestock Inventories a Sustainable Initiative Given Phosphorus Crop Removal Regulations?

As environmental regulations continue to tighten and shift from nitrogen to phosphorus-based application standards for manure, phosphorus removal will become increasingly important for any state considering a livestock growth initiative. A framework was developed that can determine a state’s phosphorus removal capacity based upon production of livestock and crops and varying phosphorus removal standards. The state level results indicate that Indiana, along with Arizona, Illinois, Iowa, Kansas, and Texas, are well positioned to undertake a livestock growth initiative given that each state has excess phosphorous removal capacity.Agribusiness, Livestock Production/Industries,

Scorecarding and Heat Mapping: Tools and Concepts for Assessing Strategic Uncertainty

The dramatic changes occurring throughout the agriculture industry are creating new and different uncertainties that result from a turbulent business climate. The objective of this paper is to present a methodology to understand, assess and evaluate, and manage strategic uncertainty. The approach is to present a mental model that frames assessment of strategic uncertainty from a potential and exposure perspective. Scorecarding and heat mapping assessment tools operationalize the mental model. Participants in an executive agribusiness educational workshop applied this mental model and the assessment tools to one of three hypothetical seed companies. The participants then provided an evaluation of the usefulness and effectiveness of uncertainty scorecarding and heat mapping.Uncertainty, scorecarding, strategic uncertainty, heat mapping, potential, exposure, likelihood, Risk and Uncertainty,

Renormalization of Higher Derivative Operators in the Matrix Model

$M$-theory is believed to be described in various dimensions by large $N$ field theories. It has been further conjectured that at finite $N$, these theories describe the discrete light cone quantization (DLCQ) of $M$ theory. Even at low energies, this is not necessarily the same thing as the DLCQ of supergravity. It is believed that this is only the case for quantities which are protected by non-renormalization theorems. In 0+1 and 1+1 dimensions, we provide further evidence of a non-renormalization theorem for the $v^4$ terms, but also give evidence that there are not such theorems at order $v^8$ and higher.Comment: 14 pages latex. Note added in light of recent development

Understanding regional water resource dynamics due to land-cover/land-use and climate changes in the North Carolina Piedmont

The spatiotemporal distribution of freshwater resources on Earth is controlled by interacting climatologic, ecological, and physical processes. These dynamics are likely to change in the future due to climate and land cover changes with important implications for life on Earth. Ecosystem simulation models which couple these processes are increasingly relied upon to provide projections of probable future changes so that resources may be sustainably managed and future growth and development planned. The majority of these models depend critically on surface descriptions such as land cover and vegetation abundance obtained from remotely sensed images, and remote sensing methods have played an essential role in accurately parameterizing and implementing models at appreciable spatial scales. However, significant challenges exist for investigations adopting an integrated remote sensing and ecosystem simulation approach. This investigation sought to quantify the likely impacts of climate change and land cover change on the water cycle of the Eno River basin in central North Carolina. Special attention was paid to addressing and overcoming existing remote sensing methodological limitations related to mapping leaf area index (LAI) and land cover. Improved methods were developed and the resulting products used to parameterize two different ecohydrologic models which were then used to quantify the hydrological effects of various climate and land cover change scenarios. The improved methods are demonstrated to overcome several of the major existing limitations to mapping LAI and land cover accurately, consistently, and efficiently with diverse data sources. These improvements lead to greater confidence in simulated results and future projections. The results of this investigation highlight the dominant role that climate plays in structuring basin response, and indicate that future changes may increase water stress in the area, particularly under scenarios of reduced growing season precipitation.Doctor of Philosoph

An Automated Images-to-Graphs Framework for High Resolution Connectomics

Reconstructing a map of neuronal connectivity is a critical challenge in contemporary neuroscience. Recent advances in high-throughput serial section electron microscopy (EM) have produced massive 3D image volumes of nanoscale brain tissue for the first time. The resolution of EM allows for individual neurons and their synaptic connections to be directly observed. Recovering neuronal networks by manually tracing each neuronal process at this scale is unmanageable, and therefore researchers are developing automated image processing modules. Thus far, state-of-the-art algorithms focus only on the solution to a particular task (e.g., neuron segmentation or synapse identification). In this manuscript we present the first fully automated images-to-graphs pipeline (i.e., a pipeline that begins with an imaged volume of neural tissue and produces a brain graph without any human interaction). To evaluate overall performance and select the best parameters and methods, we also develop a metric to assess the quality of the output graphs. We evaluate a set of algorithms and parameters, searching possible operating points to identify the best available brain graph for our assessment metric. Finally, we deploy a reference end-to-end version of the pipeline on a large, publicly available data set. This provides a baseline result and framework for community analysis and future algorithm development and testing. All code and data derivatives have been made publicly available toward eventually unlocking new biofidelic computational primitives and understanding of neuropathologies.Comment: 13 pages, first two authors contributed equally V2: Added additional experiments and clarifications; added information on infrastructure and pipeline environmen

Agent-based Modeling: A Guide for Social Psychologists

Agent-based modeling is a longstanding but underused method that allows researchers to simulate artificial worlds for hypothesis testing and theory building. Agent-based models (ABMs) offer unprecedented control and statistical power by allowing researchers to precisely specify the behavior of any number of agents and observe their interactions over time. ABMs are especially useful when investigating group behavior or evolutionary processes and can uniquely reveal non-linear dynamics and emergence—the process whereby local interactions aggregate into often surprising collective phenomena, such as spatial segregation and relational homophily. We review several illustrative ABMs, describe the strengths and limitations of this method, and address two misconceptions about ABMs: reductionism and “you get out what you put in.” We also offer maxims for good and bad ABMs, give practical tips for beginner modelers, and include a list of resources and other models. We conclude with a 7-step guide to creating your own model

Time cells in the human hippocampus and entorhinal cortex support episodic memory.

The organization of temporal information is critical for the encoding and retrieval of episodic memories. In the rodent hippocampus and entorhinal cortex, evidence accumulated over the last decade suggests that populations of time cells in the hippocampus encode temporal information. We identify time cells in humans using intracranial microelectrode recordings obtained from 27 human epilepsy patients who performed an episodic memory task. We show that time cell activity predicts the temporal organization of retrieved memory items. We also uncover evidence of ramping cell activity in humans, which represents a complementary type of temporal information. These findings establish a cellular mechanism for the representation of temporal information in the human brain needed to form episodic memories