1,560 research outputs found

    Inverter-converter automatic paralleling and protection

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    Electric control and protection circuits for parallel operation of inverter-converte

    Fusiform Rust Incidence in Loblolly and Slash Pine Plantations in East Texas

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    A method to predict the incidence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme) in unthinned loblolly (Pinus taeda L.) and slash pine (Pinus elliotti Englem.) plantations located on non-oldfields in East Texas is presented. In addition, procedures are described to estimate changes in rust incidence over time as: 1. A rust-free tree remains rust free, develops stem or branch galls, or dies. 2. A tree with branch galls remains with branch galls only, develops stem galls, or dies. 3. A tree with stem galls remains with stem galls, or dies. Multinomial logistic regression models utilizing basic plantation parameters as predictors were fit to estimate current rust incidence and, then, the change in rust condition over time. South. J. Appl. For. 15(2):79-84

    Predicting Survival of East Texas Loblolly and Slash Pine Plantations Infected with Fusiform Rust

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    Repeated measurement during 1982-1992 of East Texas Pine Plantation Research Project permanent plots in loblolly( Pinus taedaL .) and slash( Pinus elliottii Engelm.) pine plantations throughout East Texas were used to develop equations for predicting the future number of trees per acre. A typical condition of East Texas pine plantations is the incidence of fusiform rust( Cronatrium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme). A regression procedure for fitting nonlinear systems of equations was used to fit survival models that considered the possibility that trees with no rust galls on the stem could either (1) remain uninfected and alive, (2) become infected yet still alive or (3) die. For infected stem so, only two possible outcomes were considered in the model:(1) remain infected and alive or (2) die.Analyses of the differences between predicted and observed values indicated no adverse trends for either of the two species. Apparently the models do represent observed survival patterns.South J. Appl. For. 20(1):30-35

    Adolescent leisure reading and its longitudinal association with prosocial behavior and social adjustment

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    Reading is a popular leisure activity for children, teenagers, and adults. Several theories agree that reading might improve social cognition, but the empirical evidence remains tentative, with research on adolescents especially lacking. We employed a very large, and nationally representative, longitudinal dataset from the National Educational Panel Study (NEPS) in Germany to examine this hypothesis. Specifically, we tested whether reading prospectively predicted future self-reported prosocial behavior and social adjustment in adolescents, controlling for a number of covariates. Two-way cross-lagged panel analyses probed the longitudinal relationship between leisure reading and these social outcomes from Grade 6 to Grade 9. In addition, we examined the effect of cumulative reading experience across Grades 5–8 on future social outcomes, using structural equation modeling. We also explored the unique contributions of cumulative reading experience in different literary genres (classic literature, popular literature, nonfiction, comic books). Cumulative reading in general did not predict future prosocial behavior and social adjustment. However, cumulative reading of modern classic literature was positively associated with later prosocial behavior and social adjustment

    Establishment of permanent growth and yield plots in loblolly and slash pine plantations

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    Permanent plots have been established in 178 loblolly and 78 slash pine plantations throughout East Texas to study the development of stand structure over time. Analysis of the data will provide methods of estimating growth and yield, mortality, and site productivity to assist managers of these plantations

    Site Index Equations for Loblolly and Slash Pine Plantations on Non-Old Fields in East Texas

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    Equations to estimate site index (index age 25 years) for plantations of loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) on non-old fields in East Texas have been developed. The height-prediction curves were based on the Richards’ growth function and track well within the range of the data (1-17 years). South. J. Appl. For. 10:109-112, May 1986

    Optimal Control Theory Applied to a Difference Equation Model of Cardiopulmonary Resuscitation

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    Objective: To apply the mathematical techniques of optimal control theory (OCT) to a validated model of the human circulation during cardiopulmonary resuscitation (CPR), so as to discover improved waveforms for chest compression and decompression that maximize the systemic perfusion pressure (SPP). Methods: The human circulatory system is represented by seven difference equations, which describe the pressure changes in systemic vascular compartments caused by chest compression. The forcing term is the intrathoracic pressure generated by the external chest compression, which is taken as the “control” variable for the system. The optimum waveform of this forcing pressure as a function of time, determined from OCT, maximizes the calculated SPP between the thoracic aorta and the superior vena cava over a period of 13.3 sec of continuous chest compression under clinically realistic conditions. Results: The optimal waveform included both compression and decompression of the chest to the maximum allowable extent. Compression-decompression waveforms were rectangular in shape. The frequency of optimal compression-decompression was 90/min. The duty cycle (compression duration / cycle time) was 40 percent. The SPP for the optimum control waveform was 36 mmHg vs. 25 mmHg for standard CPR. Conclusions: OCT suggests that both compression and decompression of the chest are needed for best hemodynamics during CPR

    Investigation on the trophic state of the North Sea for three years (1994?1996) simulated with the ecosystem model ERSEM ? the role of a sharp NAOI decline

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    International audienceApplying the ecosystem model ERSEM to the Northwest-European shelf (48°?63°N, 15°W?12°E) the years 1994-1996 were simulated, which exhibit an extremely strong transition in North Atlantic Oscillation index (NAOI): from a high-NAOI to a low-NAOI regime. In order to be far enough from the boundaries of the model area the results and budgets are focussed on the North Sea area. For this region the model was validated against climatological values of nitrate as representative nutrient. For all three years the North Sea was found to be net heterotrophic: organic material was imported, inorganic material was exported. The strength of this "remineralisation-machine" was large during NAOI-high years (1994 and 1995). It was weaker in 1996 with a low NAOI. This was caused by higher net primary production in the northern North Sea during summer 1996. In this year the stratification was weaker and began later allowing the deep nutrient-rich water in the northern North Sea to be mixed into the upper layers also during early summer

    Characterizing Fusiform Rust Incidence and Distribution in East Texas

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    Three measurement cycles were completed on an extensive network of loblolly( Pinus taeda L.) pine and slash (Pinus elliottii Engelm.) pine plots in industrial plantations throughout East Texas in 1984, 1987, and 1990.Because the incidence of fusiform rust caused by Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme had been recorded at each measurement, it is possible to characterize the temporal and geographic distribution of fusiform rust among these industrial pine plantations in East Texas. Average rust incidence for each species by two year age classes is presented. For loblolly pine, there is no apparent change in overall average incidence between 1987 and 1990, whereas for slash pine, there is an apparent overall average decline of about 7-8 percentage points. For some slash pine age classes, the incidence decline is 20-30 percentage points. Loblolly and slash pine rust incidence maps depict the geographic distribution of rust infection by plantation age groups in East Texas. South. J. Appl. For. 18(1):29-3
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