3,874 research outputs found
RISK AND SUSTAINABLE AGRICULTURE: A TARGET-MOTAD ANALYSIS OF THE 92-YEAR "OLD ROTATION"
Target-MOTAD was used to assess the risks and returns of sustainable cotton crop rotations from Auburn University's 92-year "Old Rotation." Study results analyze rotations of continuous cotton, with and without winter legumes; two years of cotton-winter legumes-corn, with and without nitrogen fertilization; and three years of cotton-winter legumes-corn and rye-soybeans double-cropped. Ten years of observations on deviations from target income were used to identify optimal sustainable rotation(s). Study results suggest that diversification in rotations, as well as in crops, results in the least risk for a given level of target income.Risk and Uncertainty,
Permutation-adapted complete and independent basis for atomic cluster expansion descriptors
In many recent applications, particularly in the field of atom-centered
descriptors for interatomic potentials, tensor products of spherical harmonics
have been used to characterize complex atomic environments. When coupled with a
radial basis, the atomic cluster expansion (ACE) basis is obtained. However,
symmetrization with respect to both rotation and permutation results in an
overcomplete set of ACE descriptors with linear dependencies occurring within
blocks of functions corresponding to particular generalized Wigner symbols. All
practical applications of ACE employ semi-numerical constructions to generate a
complete, fully independent basis. While computationally tractable, the
resultant basis cannot be expressed analytically, is susceptible to numerical
instability, and thus has limited reproducibility. Here we present a procedure
for generating explicit analytic expressions for a complete and independent set
of ACE descriptors. The procedure uses a coupling scheme that is maximally
symmetric w.r.t. permutation of the atoms, exposing the permutational
symmetries of the generalized Wigner symbols, and yields a permutation-adapted
rotationally and permutationally invariant basis (PA-RPI ACE). Theoretical
support for the approach is presented, as well as numerical evidence of
completeness and independence. A summary of explicit enumeration of PA-RPI
functions up to rank 6 and polynomial degree 32 is provided. The PA-RPI blocks
corresponding to particular generalized Wigner symbols may be either larger or
smaller than the corresponding blocks in the simpler rotationally invariant
basis. Finally, we demonstrate that basis functions of high polynomial degree
persist under strong regularization, indicating the importance of not
restricting the maximum degree of basis functions in ACE models a priori
Rating the Financial Health of U.S. Production Agriculture using Synthetic Credit Rating
Agribusiness, Agricultural and Food Policy, Production Economics,
Modeling landscape-scale pathogen spillover between domesticated and wild hosts: Asian soybean rust and kudzu
Many emerging pathogens infect both domesticated and wild host species, creating the potential for pathogen transmission between domesticated and wild populations. This common situation raises the question of whether managing negative impacts of disease on a focal host population (whether domesticated, endangered, or pest) requires management of only the domesticated host, only the wild host, or both. To evaluate the roles of domesticated and wild hosts in the dynamics of shared pathogens, we developed a spatially implicit model of a pathogen transmitted by airborne spores between two host species restricted to two different landscape patch types. As well as exploring the general dynamics and implications of the model, we fully parameterized our model for Asian soybean rust, a multihost infectious disease that emerged in the United States in 2004. The rust fungus Phakopsora pachyrhizi infects many legume species, including soybeans (Glycine max) and the nonnative invasive species kudzu (Pueraria montana var. lobata). Our model predicts that epidemics are driven by the host species that is more abundant in the landscape. In managed landscapes, this will generally be the domesticated host. However, many pathogens overwinter on a wild host, which acts as the source of initial inoculum at the start of the growing season. Our model predicts that very low local densities of infected wild hosts, surviving in landscape patches separate from the domesticated host, are sufficient to initiate epidemics in the domesticated host, such that managing epidemics by reducing wild host local density may not be feasible. In contrast, managing to reduce pathogen infection of a domesticated host can reduce disease impacts on wild host populations
navlie: A Python Package for State Estimation on Lie Groups
The ability to rapidly test a variety of algorithms for an arbitrary state
estimation task is valuable in the prototyping phase of navigation systems. Lie
group theory is now mainstream in the robotics community, and hence estimation
prototyping tools should allow state definitions that belong to manifolds. A
new package, called navlie, provides a framework that allows a user to model a
large class of problems by implementing a set of classes complying with a
generic interface. Once accomplished, navlie provides a variety of on-manifold
estimation algorithms that can run directly on these classes. The package also
provides a built-in library of common models, as well as many useful utilities.
The open-source project can be found at https://github.com/decargroup/navlie.Comment: 6 pages, 8 figures, presented at the 2023 IEEE/RSJ International
Conference on Intelligent Robots and Systems (IROS
Modeling landscape-scale pathogen spillover between domesticated and wild hosts: Asian soybean rust and kudzu
Abstract. Many emerging pathogens infect both domesticated and wild host species, creating the potential for pathogen transmission between domesticated and wild populations. This common situation raises the question of whether managing negative impacts of disease on a focal host population (whether domesticated, endangered, or pest) requires management of only the domesticated host, only the wild host, or both. To evaluate the roles of domesticated and wild hosts in the dynamics of shared pathogens, we developed a spatially implicit model of a pathogen transmitted by airborne spores between two host species restricted to two different landscape patch types. As well as exploring the general dynamics and implications of the model, we fully parameterized our model for Asian soybean rust, a multihost infectious disease that emerged in the United States in 2004. The rust fungus Phakopsora pachyrhizi infects many legume species, including soybeans (Glycine max) and the nonnative invasive species kudzu (Pueraria montana var. lobata). Our model predicts that epidemics are driven by the host species that is more abundant in the landscape. In managed landscapes, this will generally be the domesticated host. However, many pathogens overwinter on a wild host, which acts as the source of initial inoculum at the start of the growing season. Our model predicts that very low local densities of infected wild hosts, surviving in landscape patches separate from the domesticated host, are sufficient to initiate epidemics in the domesticated host, such that managing epidemics by reducing wild host local density may not be feasible. In contrast, managing to reduce pathogen infection of a domesticated host can reduce disease impacts on wild host populations
Paradoxical patterns of sinusoidal obstruction syndrome-like liver injury in aged female CD-1 mice triggered by cannabidiol-rich cannabis extract and acetaminophen co-administration
© 2019 The Authors. Environmental Toxicology published by Wiley Periodicals, Inc. Exposure to environmental contaminants and consumption of a high, saturated fatty diet has been demonstrated to promote precursors for metabolic syndrome (hyperglycemia, hyperinsulinemia, and hypertriglyceridemia). The purpose of this study was to determine if exposure to the most prevalent environmental persistent organic pollutants (POPs) would act as causative agents to promote metabolic syndrome independent of dietary intake. We hypothesized that POPs will activate the advanced glycated end-product (AGE)-and receptor for AGE (RAGE) signaling cascade to promote downstream signaling modulators of cardiovascular remodeling and oxidative stress in the heart. At 5-weeks of age nondiabetic (WT) and diabetic (ob/ob) mice were exposed POPs mixtures by oral gavage twice a week for 6-weeks. At the end of 6-weeks, animals were sacrificed and the hearts were taken for biochemical analysis. Increased activation of the AGE-RAGE signaling cascade via POPs exposure resulted in elevated levels of fibroblast differentiation (α-smooth muscle actin) and RAGE expression indicated maladaptive cardiac remodeling. Conversely, the observed decreased superoxide dismutase-1 and -2 (SOD-1 and SOD-2) expression may exacerbate the adverse changes occurring as a result of POPs treatment to reduce innate cardioprotective mechanisms. In comparison, ventricular collagen levels were decreased in mice exposed to POPs. In conclusion, exposure to organic environmental pollutants may intensify oxidative and inflammatory stressors to overwhelm protective mechanisms allowing for adverse cardiac remodeling
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