A field experiment from 2003 to 2005 at two sites examined the impacts of forage species and legume proportion on forage sward production. Grasses generally established rapidly and out-yielded swards high in legume content, although legumes did improve forage quality. Alfalfa was retained at greater relative biomass in mixed swards than swards containing clover. Legume persistence also varied depending on neighbouring grass species. A greenhouse study examined competitive interactions between Canada thistle (a common pasture weed), white clover and Kentucky bluegrass during establishment. Although thistle was most susceptible to intra-specific competition, and strongly affected forage yield, the latter also influenced weed biomass. Competitiveness of forages depended directly on soil medium, emphasizing the importance of abiotic factors on vegetation dynamics in mixed swards. / Rangeland and Wildlife Resources

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 172-181).

A diallel analysis of eight upland cotton (Gossypium hirsutum L.) genotypes was conducted in the field over two years to determine the potential for improvement in within-boll seed yield components and fiber quality parameters. Four exotic germplasm lines from the converted race stock (CRS) collection and four commercial types representing Texas, mid-South, and Eastern production regions were crossed and evaluated in a diallel with parents but without reciprocals according to Griffing's Model I, Method 2. Significant variation for genotypic, general combining ability (GCA) effects, and specific combining ability (SCA) effects (P 0.05) were identified for all traits studied indicating potential for improvements through selection. Significant interactions of these parameters with years were also observed, suggesting that selection should be based on multiple years and or locations. In addition to effects on yield, individual seed number traits were found to respond to heat stress under controlled growth chamber conditions, suggesting their potential for use in screening genotypes for heat tolerance. These traits were not found to interact with temperature, which indicates that selection for improvements in these traits could be conducted in any environment. Improvements in seed yield components and, putatively, in heat tolerance could be achieved using CRS M-9044-0162. As expected, CRS accessions reduced fiber quality parameters in addition to other agronomic traits, suggesting that improvements for within-boll seed yield components and heat tolerance should be made utilizing a backcross approach. Also observed in this population was a superior hybrid for fiber length and fiber strength from the cross of TAM 94L-25 with PD 6186. This combination could lead to improved fiber length and strength potential in upland cotton.

This research develops yield and reliability models for fault-tolerant semiconductor integrated circuits and develops optimization algorithms that can be directly applied to these models. Since defects cause failures in microelectronics systems, accurate yield and reliability models considering these defects as well as optimization techniques determining efficient defect-tolerant schemes are essential in semiconductor manufacturing and nanomanufacturing to ensure manufacturability and productivity. The defect-based yield model considers various types of failures, fault-tolerant schemes such as hierarchical redundancy and error correcting code, and burn-in effects, simultaneously. The reliability model counts on carry-over single-cell failures accompanied by the failure rate of the semiconductor integrated circuits under the assumption of an error correcting code policy. The redundancy allocation problem, which seeks to find an optimal allocation of redundancy that maximizes system reliability, is one of the representative problems in reliability optimization. The problem is typically formulated as a nonconvex integer nonlinear programming problem that is nonseparable and coherent. Two iterative heuristics, tree and scanning heuristics, and variants are studied to obtain local optima and a branch-and-bound algorithm is proposed to find the global optimum for redundancy allocation problems. The proposed algorithms engage a multiple-search paths strategy to accelerate efficiency. Experimental results of these algorithms indicate that they are superior to the existing algorithms in terms of computation time and solution quality. An example of memory semiconductor integrated circuits is presented to show the applicability of both the yield and reliability models and the optimization algorithms to fault-tolerant semiconductor integrated circuits.

Genetic gain studies in the past have been used to evaluate the historical improvement of different traits and give insight into what magnitudes of gain might be possible in the future. Additionally, they have been carried out to defend the role of genetics during periods of stagnant or decreasing yield trends. This study was conducted over a 2-year period (2003 and 2004) and included nine current or obsolete cotton (Gossypium hirsutum L.) cultivars grown in 5 plant densities designed to evaluate varying levels of interplant competition. Plant densities were single plant culture with plants spaced 3m x 3m, 2m x 2m, 1m x 1m, 1m x 0.3m, and two commercial populations with plants spaced 1m x 0.1m. Results were analyzed for each trait to determine whether genetic gains are interrelated with tolerance to interplant competition or strictly under genetic control. The rates of genetic gain for lint yield were highest in the 1m x 0.1m, 1m x 0.3m, and 1m x 1m treatment with slopes of 8.7, 8.2, and 7.1 kg ha-1 yr-1 respectively. The slopes were each significantly smaller in the 2m x 2m and 3m x 3m spaced populations with gains of 3.6 and 1.5 kg ha-1 yr-1 respectively, implying that for lint yield, genetic gains have been made for tolerance to interplant competition. Similarly, modern maize hybrids only out perform obsolete hybrids at higher plant densities. Genetic gain for lint yield, fiber length, fiber strength, and fiber micronaire made in the context of tolerance to interplant competition is due in large part to the excellent performance of Deltapine 491 (2002) at higher plant populations.

Sorghum (Sorghum bicolor (L). Moench) is used for human consumption in parts of Africa and Asia and as an animal feed mainly in the U.S. Though sorghum grain contains higher amounts of protein than other cereal grains such as wheat and corn, it is not as readily available for enzyme degradation in humans and animals. Protein body matrices called kafirins surround the starch granules in sorghum. Because the protein is less digestible, the starch is also less digestible for biofuel production. However variation for this trait exists and the line P850029 has a higher protein digestibility compared to other normal grain sorghum lines. This increase in digestibility of protein is due to the rearrangement of the kafirins in the prolamin protein bodies where, the γ-kafirins are rearranged in the seed endosperm and the amount of γ-kafirin in the grain is also reduced. The assay to phenotype the HD trait is time consuming and unpredictable. So identifying a quantitative trait loci (QTL) controlling the protein digestibility trait in sorghum would be beneficial in breeding. A recombinant inbred lines (RILs) population derived from P850029 x ‘Sureno’, were developed and used to map QTL regulating the protein digestibility trait. A single QTL was identified on chromosome 1 between Xtxp43 and Xtxp329. Validation of the identified QTL was done on heterogenous inbred families (HIFs). The results validate the same QTL identified on the RIL population on chromosome 1. Later the high digestibility trait (HD) was integrated with the Waxy trait in sorghum. The Waxy (WX) sorghums have starch completely in the form of amylopectin. The effect of endosperm type on ethanol yield and fermentation efficiencies was studied among HD, WX and HD-WX lines. The HD-WX lines fermented in a shorter time i.e. completed fermentation in 48 h and their fermentation efficiencies were also higher around 90%. The DDGS of the HD-WX lines also had lower residual starch content and 50% higher amino acid lysine content when compared to wildtype sorghum. Moreover, the relation between endosperm traits and grain yield in sorghum has not been fully explored. In this study, we compared the yield and yield components of four unique endosperm phenotypes, HD, WX, HD-WX and wildtype lines. A total of 100 F2:4 derived recombinant inbred lines population from a cross between Tx2907/P850029 were selected with 25 lines from each HD, WX, HD-WX and wild-type line were included in the study. These lines were grown in three replications in College Station and Halfway, Texas in a randomized complete block design. The results show that there are no significant differences in the grain yield.

Boneless ribeye rolls (n = 12) and boneless top sirloin butts (n = 12) were obtained from heavy weight carcasses (mean = 407.8 kg), assigned to one of two aging treatments (dry or wet) and aged for 35 days at a commercial aging facility. Cutting tests were performed at the end of the aging period to determine retail yields. Subprimals were fabricated using the Beef Alternative Merchandising cutting styles, isolating four specific muscles: M. spinalis thoracis, M. longissimus thoracis, M. gluteobiceps, and M. gluteus medius. Retail cutting tests showed wet-aged subprimals had higher (P < 0.0001) total saleable yield percentages with decreased cooler shrink and gross cut loss percentages. This resulted in wet-aged ribeye rolls and top sirloin butts yielding 1.5 times and 1.3 times more saleable product than dry-aged counterparts, respectively. In order to determine palatability characteristics, consumer sensory evaluations and trained panel evaluations were preformed. Palatability related to aging and muscle type resulted in significant differences. From a consumer standpoint, aging treatment influenced OLIKE, FLAV, FLEVEL, and BEEFLIKE but only through the interaction of aging treatment x muscle. Clearly, consumers rated the wet-aged, M. spinalis thoracis highest in each of the previously stated attributes. Aging also affected JUIC, whereas muscle type had a significant (P < 0.0001) effect on FLVBF, TEND, LEVTEND, JUIC, and LEVJUIC. As far as trained sensory attributes were concerned, a more concrete flavor profile of aged beef was obtained. In addition, dry-aged steaks had greater (P < 0.0001) cooking yield percentages when compared to wet-aged steaks.

College admission has become increasingly competitive in the internet era. This is especially true for the highest caliber of students and institutions. College admission is a process filled with asymmetric information. One of the biggest asymmetries occurs when schools admit students not knowing whether or not students will actually enroll. This uncertainty is economically costly to schools. As national rankings become more and more influential, schools are more sensitive to their rank and the statistics that determine them. One of these is yield, the percentage of admitted students who enroll. This paper examines data on admitted students to Claremont McKenna College and uses a probit regression to predict their enrollment decision. By successfully predicting enrollment decisions schools can eliminate some information asymmetry and therefore raise their yield.

The main focus of this work is to investigate experimentally the transition to turbulence of a yield stress shear thinning fluid in Hagen-Poiseuille flow. By combining direct high speed imaging of the flow structures with Laser Doppler Velocimetry (LDV), we provide a systematic description of the different flow regimes from laminar to fully turbulent. Each flow regime is characterized by measurements of the radial velocity, velocity fluctuations, and turbulence intensity profiles. In addition we estimate the autocorrelation, the probability distribution, and the structure functions in an attempt to further characterize transition. For all cases tested, our results indicate that transition occurs only when the Reynolds stresses of the flow equals or exceeds the yield stress of the fluid, i.e. the plug is broken before transition commences. Once in transition and when turbulent, the behavior of the yield stress fluid is somewhat similar to a (simpler) shear thinning fluid. We have also observed the shape of slugs during transition and find that their leading edges to be highly elongated and located off the central axis of the pipe, for the non-Newtonian fluids examined. Finally we present a new phenomenological approach for quantifying laminar-turbulent transition in pipe flow. This criterion is based on averaging a local Reynolds number to give ReG. Our localised parameter shows strong radial variations that are maximal at approximately the radial positions where puffs first appear during the first stages of turbulent transition.

La producción de sedimentos en zonas de montaña es un motivo de preocupación no sólo por la pérdida de la fertilidad de la capa superficial de suelo, sino también debido a sus efectos aguas abajo, tales como la deposición de sedimentos en embalses. En este trabajo, la producción de sedimentos se estudio a dos escalas espaciales: una cuenca pequeña y una grande en el noreste de los Pirineos orientales. La cuenca pequeña es Cal Rodó (4,2 km2), y la grande es la cuenca Alta Llobregat del Río Llobregat (504 km2), donde a la salida se encuentra el embalse de La Baells, la primera cuenca está anidado dentro de la última. En Cal Rodó, el objetivo fue determinar y comparar los intervalos de confianza de la carga de sedimentos en suspensión a escala de evento y a escala anual. Los datos utilizados abarcan 10 años (1996-2005). Estos incluyen muestras discretas de agua recogidas por un muestreador automático de agua, lecturas de turbidez proporcionada por un sensor de infrarojo de turbidez, un sensor de ultrasonidos, y mediciones de la lámina de agua. Todo conectado a un registrador de datos. La incertidumbre de producción de sedimentos fueron evaluados por simulaciones de Monte Carlo usando la función de distribución de la carga de sedimentos y modelación de residuales. La producción total para el periodo estudiado y estimada a través de la calibración de sensores de turbidez fue 17,217.0 Mg (4,1 Mg/ha/año) y su intervalo de confianza al 90% está entre 16,311.4 Mg y 18,395.8 Mg. Por otra parte la producción de sedimentos a través de las curvas de transporte de sedimento a escala anual fue de 103,441.0 Mg (24,6 Mg/ha/año), y su intervalo de confianza oscila entre 49,107.0 Mg y 254,803.0 Mg. Las conclusiones generales son que la incertidumbre de la carga de sedimentos por las curvas de transporte de sedimentos son amplias (> 300%) y que la producción de sedimentos se sobreestimo en un orden de magnitud. Una buena distribución de las muestras en todo el hidrograma es necesaria, a fin de desarrollar las curvas de transporte más fiable. La segunda fase de este estudio fue realizada en la cuenca Alta del Río Llobregat donde la cubierta del suelo es principalmente bosque de coníferas y pastos, con presencia de algunas zonas intensamente erosionadas (badlands). El promedio anual de erosión de suelo se estimó cuantitativamente a través de RUSLE integrado en SIG. Los datos tratados provienen de las precipitaciones registradas en ocho estaciones meteorológicas que abarcan 14 años (1991-2004), las propiedades físicas del suelo, el inventario de cubierta vegetal, las características de gestión del suelo y un modelo digital de elevaciones. Todo ello se utilizó como entradas (inputs) para generar cada uno de los factores de RUSLE, las imágenes tienen una resolución de 20 m. La producción de sedimentos se calculó mediante la aplicación de una tasa de entrega de sedimentos (sediment delivery ratio SDR) a los resultados obtenidos por RUSLE. También se llevaron a cabo análisis de sensibilidad para cada uno de los factores de RUSLE y una evaluación de la incertidumbre global de erosión de suelo. Adicionalmente diversos escenarios de erosión de suelos debido al Cambio Global fueron desarrollados. La producción de sedimentos media anual fue de 3,35 Mg/ha/año y el intervalo de confianza al 90% fue entre 0,95 y 13,7 Mg/ha/año. Estos resultados son similares a los resultados de un estudio previo de batimetría del embalse el cual fue de 4.54 Mg/ha/año, y su intervalo de confianza al 90% fue entre 4,29 Mg/ha/año y 4,79 Mg/ha/año. El mapa de riesgos de erosión muestra que pequeñas áreas altamente erosionables (5%) producen el 50% de sedimento. / A better understanding of soil erosion and sediment yield in mountainous areas is needed, for management purposes and to envisage uncertainties when developing soil erosion models. In this thesis, sediment yield estimates and associated uncertainties were studied at two spatial scales: a small catchment (Cal Rodó 4.2 km2) and a relatively large basin (Upper Llobregat Basin 504 km2), the former is nested within the latter, in the SE Pyrenees, Spain. In Cal Rodó stream which is characterized by an event based regime, is assessed the uncertainty of suspended sediment load (SSL) at event and annual scales. SSL in streams are currently estimated using diverse types of sediment rating curves (SRC) that allow the interpolation and extrapolation of the discrete observations of sediment concentrations to the whole range of recorded discharges. However, the accuracy of outcomes using SRCs in mountain event based streams is still unknown. The parameters of the non-linear relationship are obtained by a log transformation and then a bias correction factor is applied, based on the residual analysis. The uncertainty of SSL can be assessed by using Monte-Carlo approaches based on the simulation of residuals. Nevertheless, when these methods are going to be applied in streams with a regime characterized by events, it is necessary to verify if different events have different discharge-concentration relationships; if this occurs, the role of events must be taken into account in the load analyses, as they modify the structure of the residuals. Results showed that when SRCs are used for interpolation between samples, paying attention to the role of events allows to avoid nonlinear bias overcorrection and to reduce the uncertainty associated with the sediment load estimates. The sediment yield from annual and seasonal rating curves were 6.0 and 5.1 times larger than the estimated by sensor calibrations. Therefore a good distribution of samples throughout the hydrograph needs to be ascertained in order to develop reliable SRCs. The second part of this research deals with soil erosion and sediment yield assessment and its associated uncertainties in the Upper Llobregat River Basin. Land cover is mainly coniferous forest and pastures with some intensely eroded areas (badlands). Annual average soil erosion was quantitatively estimated with an integration of GIS and the Revised Universal Soil Loss Equation (RUSLE). Maps for each of the factors involved where obtained with a 20 m resolution. Rainfall dataset from eight weather stations and spanning 14 years, soil properties, land cover inventory, land management features and digital elevation model were used as resource datasets to generate each of the RUSLE factor maps. Annual average sediment yield was computed by applying a sediment delivery ratio to the results obtained by RUSLE, and this result was compared with an existing bathymetric survey. Uncertainty and sensitivity analyses were undertaken for each of the RUSLE factors, in order to assess its magnitude and determine which of the factors influences the most the soil loss estimate. Results show that the annual average sediment yield was 3.35 Mg km-2 yr-1 and its confidence interval lied between 0.95 and 13.7 Mg km-2 yr-1 with 90% confidence. These results are in agreement with results from reservoir bathymetric survey. Additional comparisons of estimated sediment yield were done with empirical methods such as PSIAC and FSM. Erosion risk maps showed that about 5% of the area generated 50% of soil loss. These areas are located in steep slopes and coincide in many cases with badlands which are near the streams. Finally, sediment yield changes under climate conditions for the late 21st Century where not relevant, whilst spreading agricultural activity as in the 1950's had a relevant increase in sediment yield.