Parameter identification of nonuniform distributed RC networks

The problem of the unique parameter identification of nonuniform distributed RC networks is addressed in this dissertation. Previous literature provides for the equivalence of distributed networks with respect to the terminal characteristics. Therefore, the question is whether unique parameter identification is even possible. This work settles that question by presenting the sufficient conditions to insure a unique solution to the parameter identification problem. One theorem requires the knowledge of a driving-point impedance, the knowledge of the physical length, and the constraint that the r(x)c(x) product remains constant to insure uniqueness of the parameters r(x) and c(x). Relaxation of the r(x)c(x) product constraint allows for other combinations of r(x) and c(x) which produce identical terminal characteristics, thus destroying the uniqueness property. However, knowledge of a driving-point impedance, of the physical length, and of r(x) is sufficient to uniquely determine c(x). Sufficiency theorems which involve one of the [A,B,C,D] parameters rather than a driving-point impedance are also included. A practical parameter identification routine is then presented in order to find the unknown parameters. A Fletcher-Powell/Davidon unconstrained minimization technique is used although any routine with appropriate convergence properties may be utilized. Examples of parameter identification of known networks are given --Abstract, page iii

CASE Weight Test: A hands on approach to comparing and selecting CASE tools at Twentieth Century Services

Citation: Eaton, R. & Hayes, K. (1991). CASE Weight Test: A hands on approach to comparing and selecting CASE tools at Twentieth Century Services. CASE Trends: The Magazine for Computer-Aided Software Engineering, 3(8), 18-19R.G. Eaton and Karl W. Hayes are spearheading the implementation oflnformation Engineering (IE) at Twentieth Century Services, Inc. in Kansas City, MO. Twentieth Century had already decided on the need for automating an IE approach, so their task was straight forward: form a research group with the goal of comparing CASE vendOrs and recommending one toolset

Fundamentos filosóficos, teóricos y empíricos de la Terapia de Aceptación y Compromiso

This article has two main purposes. The first one is to present the philosophical, theoretical, and empirical underpinnings of Acceptance and Commitment Therapy (ACT). The second is to outline the importance of philosophy and theory in order to build an empirical clinical psychology that copes progressively with the needs of the field. To accomplish these purposes, we have structured the article in three distinct sections. In the first one, we will explore the philosophical assumptions of ACT, known as Functional Contextualism. In the second section, we will offer a brief history of the appliedand theoretical tradition of ACT, Behavior Analysis, and Relational Frame Theory (RFT), a modern account of human language and cognition. Finally, we will present some clinical outcomes that, although preliminary, exemplify the broad range of health problems and psychological disorders for which the ACT model has shown to have positive results. Overall we will offer a unified version of the ACT/RFT model that interconnects its multiple dimensions.El presente artículo cumple dos propósitos. En primer lugar presentar los fundamentos filosóficos, teóricos y empíricos de la Terapia de Aceptación y Compromiso (TAC), y, en segundo lugar, argumentar cuán importante es la filosofía y la teoría de cara a construir una psicología clínica empírica que afronte de un modo progresivo las necesidades del campo. Para cumplir estos propósitos, hemos estructurado el artículo en tres secciones. En la primera exploramos los presupuestos filosóficos de la TAC, el llamado Contextualismo Funcional. En la segunda sección ofrecemos una breve historia de la tradición aplicada y teórica de la TAC, esto es, el Análisis de Conducta, y acontinuación ofrecemos una aproximación moderna al lenguaje y la cognición, la Teoría de los Marcos Relacionales (TMR). Finalmente, presentamos una serie de estudios empíricos que ejemplifican de modo preliminar el amplio rango de problemas psicológicos y de la salud para los que la TAC ha mostrado resultados positivos. En conjunto, este artículo ofrece una versión unificada del modelo de la TAC/TMR que interconecta sus múltiples dimensiones

Fundamentos filosóficos, teóricos y empíricos de la Terapia de Aceptación y Compromiso

This article has two main purposes. The first one is to present the philosophical, theoretical, and empirical underpinnings of Acceptance and Commitment Therapy (ACT). The second is to outline the importance of philosophy and theory in order to build an empirical clinical psychology that copes progressively with the needs of the field. To accomplish these purposes, we have structured the article in three distinct sections. In the first one, we will explore the philosophical assumptions of ACT, known as Functional Contextualism. In the second section, we will offer a brief history of the appliedand theoretical tradition of ACT, Behavior Analysis, and Relational Frame Theory (RFT), a modern account of human language and cognition. Finally, we will present some clinical outcomes that, although preliminary, exemplify the broad range of health problems and psychological disorders for which the ACT model has shown to have positive results. Overall we will offer a unified version of the ACT/RFT model that interconnects its multiple dimensions.El presente artículo cumple dos propósitos. En primer lugar presentar los fundamentos filosóficos, teóricos y empíricos de la Terapia de Aceptación y Compromiso (TAC), y, en segundo lugar, argumentar cuán importante es la filosofía y la teoría de cara a construir una psicología clínica empírica que afronte de un modo progresivo las necesidades del campo. Para cumplir estos propósitos, hemos estructurado el artículo en tres secciones. En la primera exploramos los presupuestos filosóficos de la TAC, el llamado Contextualismo Funcional. En la segunda sección ofrecemos una breve historia de la tradición aplicada y teórica de la TAC, esto es, el Análisis de Conducta, y acontinuación ofrecemos una aproximación moderna al lenguaje y la cognición, la Teoría de los Marcos Relacionales (TMR). Finalmente, presentamos una serie de estudios empíricos que ejemplifican de modo preliminar el amplio rango de problemas psicológicos y de la salud para los que la TAC ha mostrado resultados positivos. En conjunto, este artículo ofrece una versión unificada del modelo de la TAC/TMR que interconecta sus múltiples dimensiones

Characterization of atrazine-induced gonadal malformations in African clawed frogs (Xenopus laevis) and comparisons with effects of an androgen antagonist (cyproterone acetate) and exogenous estrogen (17beta-estradiol): Support for the demasculinization/feminization hypothesis.

Atrazine is a potent endocrine disruptor that both chemically castrates and feminizes male amphibians. It depletes androgens in adult frogs and reduces androgen-dependent growth of the larynx in developing male larvae. It also disrupts normal gonadal development and feminizes the gonads of developing males. Gonadal malformations induced by atrazine include hermaphrodites and males with multiple testes [single sex polygonadism (SSP)], and effects occur at concentrations as low as 0.1 ppb (microg/L). Here, we describe the frequencies at which these malformations occur and compare them with morphologies induced by the estrogen, 17beta-estradiol (E2) , and the antiandrogen cyproterone acetate, as a first step in testing the hypothesis that the effects of atrazine are a combination of demasculinization and feminization. The various forms of hermaphroditism did not occur in controls. Nonpigmented ovaries, which occurred at relatively high frequencies in atrazine-treated larvae, were found in four individuals out of more than 400 controls examined (1%). Further, we show that several types of gonadal malformations (SSP and three forms of hermaphroditism) are produced by E2 exposure during gonadal differentiation, whereas a final morphology (nonpigmented ovaries) appears to be the result of chemical castration (disruption of androgen synthesis and/or activity) by atrazine. These experimental findings suggest that atrazine-induced gonadal malformations result from the depletion of androgens and production of estrogens, perhaps subsequent to the induction of aromatase by atrazine, a mechanism established in fish, amphibians, reptiles, and mammals (rodents and humans)

Isotopic exchange of carbon-bound hydrogen over geologic timescales

The increasing popularity of compound-specific hydrogen isotope (D/H) analyses for investigating sedimentary organic matter raises numerous questions about the exchange of carbon-bound hydrogen over geologic timescales. Important questions include the rates of isotopic exchange, methods for diagnosing exchange in ancient samples, and the isotopic consequences of that exchange. This article provides a review of relevant literature data along with new data from several pilot studies to investigate such issues. Published experimental estimates of exchange rates between organic hydrogen and water indicate that at warm temperatures (50–100°C) exchange likely occurs on timescales of 10^4 to 10^8 yr. Incubation experiments using organic compounds and D-enriched water, combined with compound-specific D/H analyses, provide a new and highly sensitive method for measuring exchange at low temperatures. Comparison of δD values for isoprenoid and n-alkyl carbon skeletons in sedimentary organic matter provides no evidence for exchange in young (350 Ma) rocks. Specific rates of exchange are probably influenced by the nature and abundance of organic matter, pore-water chemistry, the presence of catalytic mineral surfaces, and perhaps even enzymatic activity. Estimates of equilibrium fractionation factors between organic H and water indicate that typical lipids will be depleted in D relative to water by ∼75 to 140‰ at equilibrium (30°C). Thus large differences in δD between organic molecules and water cannot be unambiguously interpreted as evidence against hydrogen exchange. A better approach may be to use changes in stereochemistry as a proxy for hydrogen exchange. For example, estimated rates of H exchange in pristane are similar to predicted rates for stereochemical inversion in steranes and hopanes. The isotopic consequences of this exchange remain in question. Incubations of cholestene with D_2O indicate that the number of D atoms incorporated during structural rearrangements can be far less than the number of C-H bonds that are broken. Sample calculations indicate that, for steranes in immature sediments, the D/H ratio imparted by biosynthesis may be largely preserved in spite of significant structural changes

Evidence of Walleye Spawning in Maumee Bay, Lake Erie

Author Institution: Department of Fisheries and Wildlife, Michigan State University ; Single Spin Guide Service ; Ohio Department of Natural Resources, Division of Wildlife, Sandusky Fisheries Research UnitDuring the mid-1990s, anglers reported large numbers of walleye (Stizostedion vitreum) in spawning condition concentrated on shallow points adjacent to the Maumee River channel during spring. These fish had flowing eggs and semen and were suspected to be actively spawning in Maumee Bay. To investigate the potential of walleye spawning, we used a benthic pump to sample for eggs at five sites adjacent to the Maumee River channel and one site near Turtle Island in Maumee Bay on 5 April 1998, a time when walleye were actively spawning in rivers and on mid-lake reefs. We found walleye eggs at each of the six sites sampled. Relative abundance of eggs ranged from 17 to 2,105 per 2-min sample, with a mean of 459 (±232). Egg viability ranged from 33 to 54% across the sites and 10% of the viable walleye eggs were observed to be in late stages of embryonic development indicating that egg survival to hatching is likely. These results are the first documentation of walleye spawning in Maumee Bay, indicating that Maumee Bay is a viable spawning location for walleye, possibly representing an important source of recruitment for the Lake Erie stock

Guidance on Sampling and Monitoring for Lead in Drinking Water

This report gives guidance on the assessment of lead in drinking water at national level in the framework of the work agreed by the Parties of the Protocol Water and Health. The guidance focuses on the case that nothing is known about the lead problem in water supply. The guidance proposes creating plumbosolvency maps of every water supply zone on which basis representative zones are selected for monitoring. The Random Daytime sampling protocol is the key method. On the basis of the monitoring results an estimate of the lead problem at national level can be made.JRC.I.2-Chemical assessment and testin

Evaluating a New Shade for Feedlot Cattle Performance and Heat Stress

Heat stress in cattle results in decreased feed intake, lower daily gain, and potentially death in susceptible animals under intense conditions. A study was carried out during the summer of 2013 at the USDA-ARS U.S. Meat Animal Research Center feedlot evaluating the impact of shade on environmental conditions and cattle performance. A novel two-tiered shade was used in half of the 14 pens, each holding 30 animals. The shades were designed to reduce solar heat load by 40% to 60% and to provide traveling shade across the pen, providing varied amounts of shade area as well as varied solar reduction potential. The objective of this study was to determine if the shade was effective at improving performance (evaluated as average daily gain, feed intake, and feed to gain ratio) and reducing environmental conditions that cause heat stress. A group of mixed-breed cattle with varied genetics including both and were selected, penned on the basis of sex, and blocked by color. Production parameters of pen feed usage were measured daily, and individual body weights were taken monthly. Environmental conditions including air temperature, relative humidity, wind speed, ground temperature, and black globe temperature with and without shade were measured. Solar load on the pens was reduced when shade was provided, with both ground temperature and black globe temperature showing reductions. Cattle showed nominally better performance; however, no significant differences were found in gain or feed intake. Panting scores were significantly lower with shade provided; slopes of cattle respiration rate versus ambient temperature were significantly lower with shade during the afternoon period