Digital Commons Network^™

Characterization And Utilization Of Flavors From Undersized Crawfish., Feng Chen

LSU Historical Dissertations and Theses

Undersized processed crawfish are proposed to be a resource for effective recovery of crawfish flavors. Tail puree from undersized crawfish was hydrolyzed using protease APL-440 through response surface methodology to enrich flavor production. Optimal hydrolytic conditions were determined to be pH $8{\sim}9,\ 65\sp\circ$C, 0.3% (V/W) enzyme/substrate ratio with the reaction maintained at 33.3% puree concentration over 60 min period. Effects of storage time and extraction method on the crawfish flavor profile were evaluated. Shorter storage time gave superior flavor stocks with less oxidized flavors. The shelf-life of frozen crawfish puree was at least six months. Atmospheric simultaneous distillation-solvent extraction (A-SDE) …

An Analytical Approach To A Tree-Farm Wetland Study., Robert Cunninghame Davidge

LSU Historical Dissertations and Theses

Wetland delineation is important because federal and local government regulations limit permissible uses of wetlands. Federal delineation regulations are based upon the use of a manual jointly agreed upon by EPA, USACOE, and NRCS. The manual provides for classification of land as either wetland or non-wetland based upon the 3 criteria of soil, vegetation, and hydrology. No provision is made for gradation between categorical wetland and categorical non-wetland. Controversy has sometimes developed between landowners and environmentalists as to proper wetland classification; some delineations have been considered arbitrary. The analytical method of wetland appraisal provides a means of assigning continuous numerical …

Mating System Differences And Genetic Effects For Preweaning Traits In Beef Cattle In The Gulf Coast Region Of The United States., Dian Allison Williams

LSU Historical Dissertations and Theses

Preweaning data collected on 1,180 calves in generation five of a crossbreeding project were analysed. The systems involved were first-cross (F$\sb1$, three-breed terminal, two-, three-, and four-breed rotational and rotational-terminal. Angus (A), Brahman (B), Charolais (C), and Hereford (H) breeds were used in the F$\sb1$ and rotational phases, while Gelbvieh (G) and Simmental (S) were the terminal sire breeds. The traits studied were birth weight (BWT), preweaning gain (ADG), 205 d weight (WWT), and weaning height (WHT). Least squares analysis of variance procedures were used for comparisons of mating systems for all traits. Estimates of direct and maternal additive (Ig, …

Quantifying Sustainability In Aquaculture Production., Rex Hall Caffey

LSU Historical Dissertations and Theses

Despite increasing institutional focus in aquaculture, sustainability remains an amorphous and much debated concept. Little consensus has been identified on the issue beyond the general recognition that the concept should contain environmental, economic, and sociological considerations. This study addressed the specific, relevant question of whether politically diverse aquacuiture interests can collectively develop and agree on production-level goals and indicators of aquaculture sustainability. The research partitioned sustainability into its three subcategories: environmental, economic and social. This division facilitated the use of existing conventions of measurement and expression in each subcategory. Employing a modified Delphi technique, over 100 aquaculture stakeholders in the …

The Nature And Extent Of Species Interactions With The United States Gulf Menhaden Fishery., Janaka Anthony De Silva

LSU Historical Dissertations and Theses

I employed categorical techniques to explain patchy data on the releasable bycatch in the U.S. Gulf of Mexico menhaden fishery looking for species and areas of potential concern and potential solutions. For fishing grounds east of the Mississippi River, the odds of observing sets with high bycatch in spring and summer were greater than in the fall. Furthermore, spring bycatch rates were higher east of 89°W than in areas west of 93°W. Correspondence analysis indicated that the fate of the releasable bycatch could be classified into three major species-fate groupings. Two distinct bycatch species assemblages from April through August that …

Measuring And Modeling Northeastern Forest Ecosystem Response To Environmental Stresses, Jennifer Caroline Jenkins

Doctoral Dissertations

Because forest responses to CO$\sb2$ fertilization and associated climate change are likely to be extremely complex, numerical models representing forest response to an integrated set of future conditions can be useful predictive tools. I compared predictions of forest net primary productivity (NPP) made by two ecosystem process models (PnET-II and TEM 4.0) using different climate scenarios, spatial resolutions, and methods of representing land cover and soils. Decreasing spatial resolution did not appreciably change NPP estimates. Input datasets, particularly climate, land cover, and soil water holding capacity, were important sources of variability in NPP estimates. These datasets interacted with model structures …

Dynamics Of Dissolved Organic Carbon During Weathering And Soil Formation, Kimberly Linnea Mccracken

Doctoral Dissertations

Interactions between dissolved organic carbon (DOC) and mineral soils were examined in field and laboratory experiments. Specific emphasis was given to factors influencing DOC mobility and element release during mineral weathering and soil formation. Soil chemical and physical properties controlling equilibrium concentrations of DOC (DOC$\rm\sb{np})$ in coarse-textured forest soils were investigated using laboratory batch reactors and the initial mass isotherm approach. The influence of DOC concentration on release of metals and silica was investigated in four soil parent materials. One of four acid treatments (0.001 N HNO$\sb3$ and three concentrations of forest floor leachate) or distilled water were added to …

Timber Price Trends, Jack Lutz

Doctoral Dissertations

Timber price forecasts are important components of timberland investment analysis. Econometric models used in forecasting timber prices can be complex because demand for timber is derived through demand for other products such as paper and housing. In contrast to econometric methods, time series analysis or autoregressive techniques allow price forecasts to be made from the timber price series themselves.

A necessary condition for using time series techniques is that the timber price series be stationary or mean-reverting. The primary hypothesis in this study was that timber prices would not be stationary and time series techniques could not be applied to …

Bioavailability Of Nutrients And Metals Following Land Application Of Organic Wastes, Jianqiang Zhao

Doctoral Dissertations

Field, greenhouse and laboratory studies were conducted to investigate the effects of soil-incorporated organic wastes on nitrogen release patterns, groundwater nitrate-nitrogen levels, nutrient/metal uptake, and plant yield.

Three field studies with corn (Zea mays L.) were conducted during 1993 to 1997 at three locations in New Hampshire using a randomized complete block design with three or four replications, two or three waste materials as main plots, and various application rates as subplots. Compared to dairy manure, Concord biosolids showed a slower release rate measured as soil NO$\sb3$-N concentrations in early season but higher post-harvest levels of soil NO$\sb3$-N.

Groundwater NO$\sb3$-N …

Molecular Systematics Of Selected Members Of The Black Basses, Genus Micropterus, With Concentration On The Spotted Bass (M. Punctulatus) Species Complex., Belinda Fuller

LSU Historical Dissertations and Theses

This study examined genetic relationships among selected populations of black basses. These centrarchid fishes, separated by both physical barriers (land formations) and distance, have shown varying degrees of differentiation, but retain many morphometric characters in common. Eight populations representing four taxa and geographical extremes in the genus Micropterus, with concentration on the spotted bass complex, were selected and evaluated for biochemical genetic characters. This study examined two species and two subspecies of spotted basses. The type species from Kentucky represented Micropterus punctulatus punctulatus; a population from Alabama represented M. p. henshalli. A Texas population, previously classified as conspecific with spotted …

Measurement And Inheritance Of Resistance To Sheath Blight Caused By Rhizoctonia Solani Kuhn In Rice., Xueyan Sha

LSU Historical Dissertations and Theses

Sheath blight (ShB), caused by Rhizoctonia solani Kuhn, has been the most destructive rice disease in Louisiana. To breed ShB resistant varieties, an effective procedure for screening progenies of segregating populations is required and detailed knowledge of the mode-of-inheritance of partial ShB resistance is also necessary. In this study four inoculation methods; rice hull/grain mixture (MIX), rice straw, toothpick, and brown rice, along with five assessment systems; 0-9 rating scale (RAT9), relative lesion height (RLH), disease severity (DS), disease incidence, and lesion height were compared on nine rice genotypes showing different resistance levels to ShB. Progenies of segregating populations from …

Factors Affecting Root Colonization By Calonectria Ilicicola And Development Of Red Crown Rot Disease On Soybean., Pali Upulmathie De Silva Kuruppu

LSU Historical Dissertations and Theses

Red crown rot of soybean caused by Calonectria ilicicola is a serious disease in Louisiana. The pathogen infects soybean roots and the above ground symptoms and signs appear during reproductive stages of the plant. Little information is available on root infection as well as effects of environmental factors or varietal resistance on this process. Field studies were conducted in 1994, 1995, and 1996 to determine the effects of planting date, cultivar susceptibility, and soil pathogen population on soybean root colonization by C. ilicicola and subsequent disease development. Early season colonization of tap as well as lateral roots was important for …

Effect Of Recycled Fiber, Compatibilizer And Pre-Formed Fiber Handsheet On The Performance Of Wood-Polyolefin Composites., Chin-Yin S. Hwang

LSU Historical Dissertations and Theses

Effects of recycled materials on the properties of hardboards, of compatibilizer on the wettability and interfacial shear strength of wood and plastics, and of handsheet configuration on the properties of wood fiber-polyolefin laminates were studied. Recycled fibers from three sources showed considerably higher holo- and alpha-cellulose contents, lower extractive and lignin contents, and shorter fiber length than virgin southern pine fiber. Replacing virgin fiber with recycled fiber adversely affected mechanical properties, dimensional stability and wettability of fiberboards. Using layered structures while substituting 20% virgin fiber with polyethylene appreciably increased dimensional stability. Internal bond strength of hardboards made from virgin fiber, …

Apoptosis, Pcna, And P53, In Fundulus Grandis Fish Liver After In-Vivo Exposure To Mnng And 2-Af., Uriel Blas-Machado

LSU Historical Dissertations and Theses

Dysfunction in homeostatic mechanisms of cell death and proliferation are considered to be important in carcinogenesis. The p53 gene has been implicated in the regulation of cell death and proliferation. The host response was measured through sequential immunohistochemical (IHC) detection of apoptosis, PCNA, and p53 in livers of Fundulus grandis fish exposed to MNNG or to 2-AF, two known carcinogens. Studies performed determined the stability of MNNG in saltwater, the suitability of different fixatives on IHC detection of apoptosis, PCNA-PC10, and p53 (various clones), and frequencies of expression of apoptosis, PCNA, and p53. A total of 996 fish specimens were …

Dietary Nitrogen And Energy Metabolism In The Ruminant: Effect Of Source Of Nitrogen., Angelica Maris Chapa

LSU Historical Dissertations and Theses

Three experiments were conducted to determine the effects of dietary nitrogen on the energy status of ruminants and the feasibility of using L-carnitine to prevent the negative effects associated with overfeeding nitrogen. The objectives of the first experiment were to monitor the nitrogen and energy status of cows grazing ryegrass pastures through the measurement of key blood metabolites and insulin and to determine the protein supplementation scheme which would maximize milk yield and maintain plasma urea nitrogen levels below dangerous levels. In the first experiment, the protein supplement that supplied excess total protein exerted negative effects on body condition and …

Supplemental Organic Chromium For Dairy Calves., Christopher L. Depew

LSU Historical Dissertations and Theses

In Exp. 1, 42 calves were fed milk replacer and then starter either with or without 1 ppm supplemental chromium (Cr) as Cr-picolinate. Neither Cr nor sex affected growth performance. With the exception of plasma nonesterified fatty acid concentrations (NEFA), weekly plasma metabolites were not affected by Cr or sex. Pre- and postfeeding plasma NEFA concentrations were lower in Cr-fed calves, but were not affected by sex. AU calves seemed to become less insulin sensitive with age, as plasma glucose became lower and insulin higher as calves became older. During i.v. glucose tolerance tests (IVGTT), calves cleared glucose faster at …

Sustainable Resources Utilization And Implications For Economic Development In Sub-Saharan Africa: A Case Study Of Cote D'Ivoire., Ahile Nicolas Koudou

LSU Historical Dissertations and Theses

In the 1960's, sub-Saharan Africa had one of the world's largest rain forests. Today, however, Africa accounts for only 27 percent of the world's forest area. Expansion of agricultural lands at the expense of forests remains the fundamental contributor to deforestation in Cote d'Ivoire. Other factors include a high natural rate of population growth (3.9 percent annually) and flexible immigration policies that create land use pressures. Consequently, Cote d'Ivoire has lost almost 83 percent of its 16 million hectares (39.5 million acres) of tropical forests. Some corrective actions, such as halting illicit harvesting, reforestation and reforming logging activities, have been …

Development Of An Integrated Algal/Seed Clam Unit Using Recirculation, Computer-Control, And Fluidization Technologies., Timothy John Pfeiffer

LSU Historical Dissertations and Theses

Computer-control, recirculation, and fluidized-bed technologies were utilized in the integration of a land-based seed clam nursery system with an algae production system to improve northern quahog seed production (6-10 mm). The components of the integrated system included: a seawater treatment system; an algae production system; a seed clam nursery system; and a computer-control system. Treatment of the incoming seawater for the integrated system included filtration (20, 1, and 0.5 micron), chlorination, UV sterilization, and ozonation. During the summer months a chiller was used to maintain the treated seawater at approximately $\rm 20\sp\circ C.$ The diatom, Chaetoceros muelleri, was cultured in …

Spatial Variability Of Coastal Organic Soil Characteristics., L. Cecil Dharmasri

LSU Historical Dissertations and Theses

This dissertation is a part of the Louisiana NASA/EPSCoR (Experimental Program to Stimulate Competitive Research) global change research, which studied the fate of carbon and sediments within the Barataria Bay Basin, Louisiana. It studied water composition to assess seawater influence within the marsh. Ion exchange resin strips were used to study the effect of salinity and Chloride (Cl) on sulfate (SO4) reduction and their potential for water and soil analysis. Chloride dominated the water system and the Cl/SO 4 ratio can be used to assess the seawater influence. Resin extractable sulfur (S) predicted non-pyritic S fraction for the marsh soils. …

Influence Of Diet And Genetic Strain On Desirable Flavors In Farm-Raised Catfish., Carol Ann Kelly

LSU Historical Dissertations and Theses

This farm-raised catfish quality study measured desirable flavor attributes, Chickeny, Nutty, Fat Complex, Corn, Sweet, with the objective to determine effects of feed ingredients, time-on-diet and genetic strain. Overall flavor impact differences were tested by triangle tests. The diets were Casein-base reference feed by itself or partially substituted with: 10% catfish meal, 10% meat and bone meal, 10% rice bran, or 3% menhaden oil and commercial feed formulation. Fish were grown indoors to minimize environmental flavors for 70, 160, 210 and 318 days. The genetic strains evaluated were channel, albino channel, blue, hybrid channel x blue, and black bullhead catfish. …

Prevention Of Hydrolytic And Oxidative Rancidity And Nutrient Losses In Rice Bran During Storage., Fatemeh Malekian Ramezanzadeh

LSU Historical Dissertations and Theses

Freshly milled raw rice bran was stabilized with microwave heat for 3 min. Half of raw and treated bran were packed in Ziplock(c) bags and the other half vacuum packed. Half of the samples were stored at 4--5°C and the other half at 25°C for 16 weeks. The free fatty acid (FFA) content increased rapidly in raw rice bran samples vacuum packed and samples packed in Ziplock(c) bags store at 25°C from an initial amount of 2.5% to 54.3% and 48.1%, respectively. FFA level increased significantly in raw samples vacuum packed and packed in Ziplock (c) bags stored 4--5°C from …

Evaluation Of Chemical Treatments And Intrinsic Factors That Affect The Mutagenic Potential Of Aflatoxin B1-Contaminated Corn., Armando Burgos-Hernandez

LSU Historical Dissertations and Theses

In the present project the use of ammoniation and fermentation as an integrated process was studied in order to give aflatoxin-contaminated corn an alternative use. Aflatoxin-contaminated corn can be fermented to obtain fuel alcohol and decontaminated distiller's dried solid grains (DDSG) can be used for animal feed. The efficacy of a fermentation process, with the inclusion of ammonium persulfate, for the decontamination of aflatoxin B$\sb1$-contaminated yellow corn was studied, as well as the effect of peroxides on the ethanol production. Addition of 2.0% ammonium persulfate decreased the aflatoxin B$\sb1$ levels by 87%. Peroxides did not have an effect on ethanol …

Aflatoxin B(1) And Fumonisin B(1) Co-Contamination: Interactive Effects, Possible Mechanisms Of Toxicity, And Decontamination Procedures., Rebeca Lopez-Garcia

LSU Historical Dissertations and Theses

The current study evaluated interactions between the mycotoxins aflatoxin B$\sb1$ (AFB$\sb1$) and fumonisin B$\sb1$ (FB$\sb1$) in pure systems as well as in corn. During storage at 25$\sp\circ$C with high moisture (ca. 50%), corn contaminated with Aspergillus flavus (L13) and/or Fusarium moniliforme (A00102) presented different aflatoxin and fumonisin levels. Toxin production/degradation varied over storage time (0-45 days). Evaluation of the mutagenicity of unifungal or bifungal corn extracts with the Salmonella/microsomal assay (tester strains TA-100 and TA-98) with metabolic activation (S9) showed positive mutagenic responses. Different ratios of pure AFB$\sb1$/FB$\sb1$ produced divergent mutagenic responses (tester strains TA-100 and TA-98) with S9. The …

Rapid Assessment Of The Bacteriological Quality Of Milk By The Use Of Adenosine Triphosphate Bioluminescence., Pushpa John Samkutty

LSU Historical Dissertations and Theses

Raw milk samples (n = 246) and pasteurized milk samples (n = 104) were analyzed to determine adenosine triphosphate (ATP) and compared with the standard plate count (SPC). An ATP filtration method was used to filter milk samples prior to ATP determination, which was measured in relative light units (RLU). The ATP assay took approximately 7 minutes to complete and could allow rapid prediction of SPC which is a measure of raw milk quality. Linear regression analysis was performed on data from three raw milk treatments defined as; fresh milk samples, samples preliminarily incubated at 12.8 and 15.6$\sp\circ$C for 18 …

The Behavior Of Invert Sugar In Sugar Refining., Jianmei Yu

LSU Historical Dissertations and Theses

Alkaline degradation of pure invert and invert in refining materials including washed sugar liquor, melt liquor and affination syrup has been investigated. The pseudo-first-order reaction kinetics of invert alkaline degradation was demonstrated for a pH range of 9.0-11.0 and a temperature range of 70-90$\sp\circ$C. In this range, rate constants of invert degradation increased 5 to 6 times with one unit increase in pH. The effects of pH and temperature on rate constants were quantified and could be expressed as: log k = 19.42 - 6712/T - 0.712pOH. Rate constants of invert alkaline degradation at different pH-temperature-base combinations calculated by this …

Biological And Molecular Properties Of Potyviruses Isolated From Sweet Potato., Eliezer Rodrigues De Souto

LSU Historical Dissertations and Theses

Ten potyvirus isolates from sweet potato (Ipomoea batatas) cv. Beauregard showing russet crack symptoms and three other isolates associated with internal cork and feathery mottle symptoms were obtained from commercial fields in the United States. The biological properties of these isolates and those of a mechanically transmitted virus obtained from I. purpurea were compared with a previously characterized sweet potato feathery mottle virus strain (SPFMV-C) from North Carolina. The symptoms induced in a range of hosts indicated that two of the isolates were associated with russet crack symptoms in the cultivar Jersey; however, none of them could be associated with …

Granular Activated Carbon From Agricultural By-Products: Carbon Properties And Their Relationship To Sugar Decolorization Potential., Mohamed Ahmedna

LSU Historical Dissertations and Theses

Representative samples of soft, low density, group 1 (rice straw, rice hulls, sugarcane bagasse) and hard, high density, group 2 agricultural by-products (pecan shells) were converted into granular activated carbons (GACs). Prior to pyrolysis, group 1 by-products were mixed with four binders, sugarcane molasses, sugar beet molasses, corn syrup and coal tar. GACs were produced from group 1 and 2 materials by physical activation (carbon dioxide, steam) or from group 2 materials by chemical activation (phosphoric acid). Carbons were evaluated for their physical (hardness, bulk density), chemical (ash, pH), surface (total surface area, pore size distribution, surface oxides) and adsorption …