813 research outputs found

    Fusiform Rust Trends in East Texas: 1969-1987

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    Five surveys of pine plantations in East Texas over an 18-year period (1969-1987) indicated that fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme Birdsall and Snow) infection rates have increased to current levels of about 50% on slash pine (Pinus elliottii Engelm.) and are continuing to increase on loblolly pine (Pinus taeda L.) to 10-15% levels. South. J. Appl. For. 12(4):259-26

    Tree Content and Taper Functions for Loblolly and Slash Pine Trees Planted on Non-Old-Fields in East Texas

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    Equations are presented to estimate total or partial stem content in cubic feet and pounds (green or dry) for loblolly pine (Pinus taeda L.) and slash pine (Pinus elliotti Engelm.) trees planted on non-old-fields in East Texas. Equations are included to estimate the content of the complete tree (stem and branches). In addition, a set of compatible stem taper functions are described. South. j. Appl. For. 11(3):147-15

    Research Report No. 18, Fusiform Rust Occurrence in East Texas Pine Plantations, 1969-1987

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    Information from five surveys of slash pine ( Pinus ellioitti Engelm. ) and loblolly ( Pinus taeda L. ) pine plantations in East Texas between 1969 and 1987 indicated that infection rates for fusiform rust ( Cranatlium quercuum (Berle) Miyabe ex Shirai f. sp. fusiforme) have increased to about 50~ for slash pine and are continuing to increase for loblolly pine to current levels of 10- I 5:t

    Texas Forestry Paper No. 3

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    Site index curves for old-field loblolly pine plantations in northeast texashttps://scholarworks.sfasu.edu/texas_forestry_papers/1004/thumbnail.jp

    Research Report No. 19, Estimating Survival for East Texas Pine Plantations

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    Equations to estimate the expected number of trees per acre at future points within a rotation are presented for planted lob lolly pine ( Pinus taeda L. ) and slash pine ( Pinus elliottii Engelm ) trees on non-old-fields in East Texas. Separate functions are presented for fusiform rust infected trees and uninfected trees

    Optimal control measures for a susceptible-carrier-infectious-recovered-susceptible malware propagation model

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    Purposing to lessen malware propagation, this paper proposes optimal control measures for a susceptible-carrier-infectious-recovered-susceptible (SCIRS) epidemiological model formed by a system of ordinary differential equations. By taking advantage of real-world data related to the number of reported cybercrimes in Japan from 2012 to 2017, an optimal control problem is formulated to minimize the number of infected devices in a cost-effective way. The existence and uniqueness of the results related to the optimality system are proved. Overall, numerical simulations show the usefulness of the proposed control strategies in reducing the spread of malware infections.- Fundação para a CiĂȘncia e Tecnologia, Grant/Award Number: UID/MAT/04106/2019 and UID/CEC/00319/201

    Reframing Optimal Control Problems for Infectious Disease Management in Low-Income Countries

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    Optimal control theory can be a useful tool to identify the best strategies for the management of infectious diseases. In most of the applications to disease control with ordinary differential equations, the objective functional to be optimized is formulated in monetary terms as the sum of intervention costs and the cost associated with the burden of disease. We present alternate formulations that express epidemiological outcomes via health metrics and reframe the problem to include features such as budget constraints and epidemiological targets. These alternate formulations are illustrated with a compartmental cholera model. The alternate formulations permit us to better explore the sensitivity of the optimal control solutions to changes in available budget or the desired epidemiological target. We also discuss some limitations of comprehensive cost assessment in epidemiology

    Optimal fishery with coastal catch

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    In many spatial resource models, it is assumed that an agent is able to harvest the resource over the complete spatial domain. However, agents frequently only have access to a resource at particular locations at which a moving biomass, such as fish or game, may be caught or hunted. Here, we analyze an infinite time‐horizon optimal control problem with boundary harvesting and (systems of) parabolic partial differential equations as state dynamics. We formally derive the associated canonical system, consisting of a forward–backward diffusion system with boundary controls, and numerically compute the canonical steady states and the optimal time‐dependent paths, and their dependence on parameters. We start with some one‐species fishing models, and then extend the analysis to a predator–prey model of the Lotka–Volterra type. The models are rather generic, and our methods are quite general, and thus should be applicable to large classes of structurally similar bioeconomic problems with boundary controls. Recommedations for Resource Managers Just like ordinary differential equation‐constrained (optimal) control problems and distributed partial differential equation (PDE) constrained control problems, boundary control problems with PDE state dynamics may be formally treated by the Pontryagin's maximum principle or canonical system formalism (state and adjoint PDEs). These problems may have multiple (locally) optimal solutions; a first overview of suitable choices can be obtained by identifying canonical steady states. The computation of canonical paths toward some optimal steady state yields temporal information about the optimal harvesting, possibly including waiting time behavior for the stock to recover from a low‐stock initial state, and nonmonotonic (in time) harvesting efforts. Multispecies fishery models may lead to asymmetric effects; for instance, it may be optimal to capture a predator species to protect the prey, even for high costs and low market values of the predators

    Dental and craniofacial defects in the Crtap−/− mouse model of osteogenesis imperfecta type VII

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    BackgroundInactivating mutations in the gene for cartilage‐associated protein (CRTAP) cause osteogenesis imperfecta type VII in humans, with a phenotype that can include craniofacial defects. Dental and craniofacial manifestations have not been a focus of case reports to date. We analyzed the craniofacial and dental phenotype of Crtap−/− mice by skull measurements, micro‐computed tomography (micro‐CT), histology, and immunohistochemistry.ResultsCrtap−/− mice exhibited a brachycephalic skull shape with fusion of the nasofrontal suture and facial bones, resulting in mid‐face retrusion and a class III dental malocclusion. Loss of CRTAP also resulted in decreased dentin volume and decreased cellular cementum volume, though acellular cementum thickness was increased. Periodontal dysfunction was revealed by decreased alveolar bone volume and mineral density, increased periodontal ligament (PDL) space, ectopic calcification within the PDL, bone‐tooth ankylosis, altered immunostaining of extracellular matrix proteins in bone and PDL, increased pSMAD5, and more numerous osteoclasts on alveolar bone surfaces.ConclusionsCrtap−/− mice serve as a useful model of the dental and craniofacial abnormalities seen in individuals with osteogenesis imperfecta type VII.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155878/1/dvdy166.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155878/2/dvdy166_am.pd

    Unified analysis of terminal-time control in classical and quantum systems

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    Many phenomena in physics, chemistry, and biology involve seeking an optimal control to maximize an objective for a classical or quantum system which is open and interacting with its environment. The complexity of finding an optimal control for maximizing an objective is strongly affected by the possible existence of sub-optimal maxima. Within a unified framework under specified conditions, control objectives for maximizing at a terminal time physical observables of open classical and quantum systems are shown to be inherently free of sub-optimal maxima. This attractive feature is of central importance for enabling the discovery of controls in a seamless fashion in a wide range of phenomena transcending the quantum and classical regimes.Comment: 10 page
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