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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Technical, value, and institutional aspects of integrated use conflicts: A timber and water management case study.

Abubakar, Mohammad Mahmood. January 1990 (has links)
This research examined the technical, social, and institutional aspects of integrated (multiple-use) watershed management conflicts, with a focus on timber and water management. The problem was first examined from a general perspective. Then, a specific case study was analyzed. The Bull Run watershed near Portland, Oregon, was chosen for the case study, because it provides a well-known and long-standing example of conflict over timber harvesting and water quality protection. Analyses were conducted on the relationship of logging and water quality, economics of information, conflicts and institutional sources of conflicts in integrated watershed management, available information and value of additional information. Forested watersheds commonly are managed for multiple purposes, one of which is the production of high quality potable water. Conflicts often arise when another of those purposes is timber production, because logging is perceived as a threat to water quality. These conflicts can result from uncertain factual information, from differences underlying social values, or from perceived imbalances in the incident of costs and benefits. Resulting conflicts may go unresolved because existing institutional structures are incapable of resolving disputes. When such conflicts go unresolved, benefits are often lost, and social, political, and managerial costs are high. This study found that the roots of conflict often lie in value differences or in interest impacts, but attention is focused inappropriately and unproductively on factual issues. This research should point the way to resolution of long-standing disputes in the management of forested watersheds by identifying the root causes of these disputes and choosing those actions, whether they be change management guidelines, additional information collection, or altered institutional structure, which may be effective in resolving them.
2

Dietary effects on energy metabolism of laying hens as determined by indirect calorimetry.

Alak, John Ishaya Banza. January 1990 (has links)
Indirect calorimetry was employed to evaluate adequacy of various diets for laying hens. Effects of supplemental fats (animal fat, corn oil, olive oil and menhaden oil) and their combinations were evaluated; phosphorus deficiency was used to evaluate effects of mineral inadequacy; and methionine deficiency was used to determine effects of dietary amino acid balance and protein quality. Addition of animal fat and vegetable oil to laying hen diets at a level of 7% significantly (P $<$.05) increased both maintenance metabolizable energy (ME) requirement and fasting heat production (FHP). With the exception of menhaden oil, all fat supplements significantly (P $<$.05) improved energy intake, energy retention (balance) and net energetic efficiency (NEE) of dietary ME conversion to net energy in eggs and body tissues. An olive oil-animal fat (1:1) combination produced the highest NEE (96%) and ME intakes. Comparison of egg yolk fatty acids with those in corn oil, animal fat, olive oil and olive oil-animal fat combination yielded correlation coefficients of.096,.890,.824 and.954, respectively, suggesting that fatty acids in the olive oil-animal fat combination most closely resemble those in egg fat. Diets formulated to contain 16% protein and.18% available phosphorus supported an egg production rate of 70.6% which was increased to 76.7% with supplementation to.35% available phosphorus. Feed intake and conversion were improved with phosphorus supplementation at the low protein level, but not at 19% protein. Heat production was higher for the low phosphorus-fed birds a each protein level. Daily maintenance ME requirement and FHP were increased with the high protein diets. The 16% dietary protein level was adequate to support both egg production and egg weight if sufficient available phosphorus was present in the diet. However, the 19% dietary protein level was detrimental to performance. Total sulfur amino acid (TSAA) intake and egg mass were increased with supplemental DL-methionine. Low TSAA levels resulted in higher heat production, and maintenance ME requirements with concomitantly lower NEE. A TSAA requirement of 514.7 mg/bird/day was estimated to support an egg mass of 47 g/bird/day. Indirect calorimetry estimated the TSAA requirements as 591.5 to 629.9 mg/bird/day for maximum energetic efficiency and energy balance, respectively.
3

Effects of sorghum grain processing and forage fiber source on milk production, digestibility and kinetics of passage in Holstein cows.

Poore, Matthew Henry. January 1990 (has links)
Experiments were conducted to determine effects of source of forage and starch degradability on milk production, digestibility and passage in Holstein cows. A preliminary experiment showed that sampling site, dosing time and passage model had little influence on passage parameter estimates for grain in lactating cows. Mean retention times were 17 and 25 h for duodenal and fecal sampling, respectively, and 16 and 18 h at the duodenal site and 24 and 26 h at the fecal site for doses given before rather than after feeding, respectively. In an 8 wk trial cows in early lactation were fed diets with 30% NDF with forage NDF from wheat straw or alfalfa hay in proportions of 0:3, 1:2, 2:1 or 3:0. Intake and milk yield were not influenced, but milk fat percentage, acetate to propionate ratio (C2:C3) and persistence were decreased with increasing straw, and yield of FCM decreased on all straw. Ratio of forage NDF to ruminally degradable starch (FNDF:RDS) was 1.10 1.01,.92 and.84 in 0:3, 1:2, 2:1 and 3:0 diets, respectively, and it was concluded that a ratio of <1:1 would result in low C2:C3, and poor persistence. In another 8 wk trial, cows were fed diets formulated to contain equal forage NDF from wheat straw or alfalfa hay, and steam-flaked or dry-rolled sorghum grain in a 2 x 2 factorial arrangement of treatments. All diets had FNDF:RDS >1:1. Forage source did not influence any performance parameter nor did forage source interact with grain processing. Steam-flaking grain increased milk yield 12%, milk protein yield 14% and improved efficiency and persistence. Although milk fat percentage was decreased from 3.6 to 3.2, yield of milk fat was not influenced. It was concluded that increasing starch degradability may improve performance if the ratio of FNDF:RDS is maintained > 1:1. In the last experiment, duodenally cannulated cows were fed diets similar to those in the second lactation trial, except straw was substituted for 2/3 of the alfalfa hay on an NDF basis. Substituting straw for alfalfa did not influence flow of OM, starch or any CP fraction, but resulted in decreased (54 vs 47%) ruminal cellulose digestibility. Steam-flaking sorghum grain increased ruminal digestion of starch (74 vs 48%), increased flow of non-ammonia CP (120 vs 110% of intake) and bacterial CP (2.8 vs 2.2 kg/d), and decreased ruminal digestibility of cellulose (47 vs 53%), compared to dry-rolling. Response to steam-flaking in the lactation trial was probably due to both increased energy availability and improved duodenal flow of CP.
4

Phosphates in suspensions of alkaline, basaltic soils.

Brito, Jorge Manuel Santos Sousa. January 1990 (has links)
The phosphate solid-solution activities in the A and A₁ horizons of ten alkaline soils from basalt were calculated in order to assess their conformity to solid-solution behavior. Nine soils were from the Cape Verde Islands and one from Arizona. Four of the Cape Verdean soils belonged to the same series (Ponta) but presented different levels of P fertilization. The other soils were not fertilized. All soils behaved in conformity with solid-solution theory. Three assumptions were made: (1) Surfaces of minerals are similar because of weathering; (2) Partial equilibrium was reached; (3) The mole fraction of the total solid composition is similar to the X of the surface of the solid. A preliminary test was conducted for optimization of experimental conditions, which turned out to be: 24-25°C; 1:5 soil solution ratio; 0.01M CaCl₂ extracting solutions. The relation of pH vs. time was used as the indicator of change and suspensions were kept for 21 days until pH stabilization. After filtration, electrical conductivity, soluble Ca, Mg and P were measured. A second experiment was done on selected samples, in order to study the influence of added Ca on the Solid Activity Coefficient (SAC). SAC and ionic solid activity coefficients for phosphates were computed from the data and the equation IAP = g X Ksp. Ksp of different Ca phosphates were taken as reference. Best results were found with octocalcium phosphate and bobierrite as reference for calcium and magnesium phosphates respectively. The curves of log SAC vs. P(added) were linear, indicating confirmation of solid solution behavior. Fertilized and virgin soils presented different slopes for those curves. Based on octocalcium phosphate, the basaltic soils yielded phosphate ionic solubility coefficients on the range 1 to 4 which are very low compared with similar coefficients calculated in the literature for non basaltic soils. The amorphous nature of basaltic minerals was considered as an explanation for the solid-solution behavior observed. Results show reasonable conditions for magnesium phosphate formation and no influence of added Ca on the linearity of log SAC vs. P(added) plots. However Ca levels corresponding to I.S. around 0.028 produced a considerable drop on the values of SAC when bobierrite was taken as reference.
5

Modeling water quality for soils containing gypsic horizons.

Arslan, Awadis. January 1990 (has links)
A computer simulation model was developed to simulate the impact of irrigating soils containing gypsic horizons on soil water quality and percolated water quality. The model simulates saturated - unsaturated solute movement using the mixing cell approach to simulate dispersion and movement of soluble salts. Dissolution and precipitation of slightly soluble salts and the formation of ion pairs is considered as a function of temperature. Van Genuchten closed form equation is used to find soil water retention function. Finite difference method was applied to Richards equation for moisture movement simulation in the profile. The model predicts the concentration of the major cations and anions in each segment. The regression coefficients of the observed vs. simulated concentration of the major ions were higher than 0.961 in all the three replicates with slopes ranging between 0.717 and 0.940. Running the model at 1 and 41 °C showed significant differences in Ca, SO₄, and HCO₃ concentrations in the percolated water. However, the differences in Cl, Na, and Mg concentrations were not significant. The presence of high Ca and SO₄ concentrations in the irrigation water reduced gypsum solubility in soils containing a layer of gypsum compared with the presence of Mg and Cl in the irrigation water.
6

The nutritional value and toxic properties of buffalo gourd (Cucurbita foetidissima) plant.

Fellah, Abdulmunam Mohamed. January 1990 (has links)
Buffalo gourd (BG), Cucurbita foetidissima, vine contains a material that was toxic to mice. Extracting the vine with either water or ethanol greatly improves the performance of the mice. However, water treatment of the vine had removed the bitter substances and gave a better response than ethanol extraction which partially reduced these materials. Chicks received up to 10% of BG seeds in a soybean meal diet had no significant change in their growth as compared to those fed control diet. However, as the concentration of the seeds increased to 20% or above, a significant reduction in chicks performance were found in comparison to the soybean meal. Signs of toxicities which caused high mortality rate were also observed in those chicks. Cleaning and washing of BG seeds did not improve chicks performance as compared to those on uncleaned-unwashed seeds. Birds fed BG hulls were not significantly different than the control diet and showed no signs of neuromuscular abnormalities or death. Feeding defatted seeds and defatted embryo diets depressed the growth. The addition of 24% of BG seeds to the regular soybean meal diet showed no difference in growth as compared to the control birds. The neuromuscular abnormalities were observed only in birds fed defatted seeds, defatted embryo and whole seed diets but not hulls or whole seed uncleaned diets. This raises a serious issue of just what is causing these neuromuscular problems in some diets and not all of them. These abnormalities disappeared after the chicks were shifted back to the regular starter diet. Incorporation of 10% of the whole BG roots in practical chick ration significantly depressed growth. Toxicity problems were also observed in these chicks. Water extraction of the roots improved performance and appeared to reduce the bitter material in the diet and the incidence of mortality when compared to those fed the dried roots. A preliminary study using silage as prepared from BG forage has shown no palatability problems when fed to young heifers. Incorporation of milo with BG forage did not improve the palatability of the silage. This was a great improvement in feed intake values when compared to the feeding of fresh cut forage to calves or cows.
7

Aerial transmission and strategies for control of Pythium on hydroponically grown cucumbers.

Goldberg, Natalie Pauline. January 1990 (has links)
Recirculating hydroponic cultural systems facilitate continuous dissemination of introduced plant pathogens. Chemicals are unavailable for the control of diseases in hydroponically-grown vegetables, thus alternate methods of control need to be investigated. An experiment was conducted to test the efficacy of filtration of infested water for the control of root rot of cucumber caused by Pythium aphanidermatum. Germinated cucumber seedlings were transplanted into separate hydroponic tanks. Each tank received water from a common source tank which was (a) recirculated through a 20-μm filter or (b) through a 7-μm filter. Pythium aphanindermatum was introduced into the source tank on two infected plants. Recirculation of infested water was conducted every other day for 5 days at a flow rate of 114 L/min for 30 min. One day after recirculation, 67% of the plants in the tank receiving water passed only through the 20-μm filter were infected and all plants were infected within 3-days. None of the plants in the tank which received water passed through the 7-μm filter were infected until 5-days post-recirculation. A repeat experiment yielded similar results, however there was a delay in the onset of disease expression. The fungus was recovered from the surface (0 mm) and middle (8 mm depth), but not from the inner core (16 mm depth) of the 7-μm filter. It was concluded that the 7-μm filter was effective in removing zoospores from infested water. Since plants in the tank receiving water passed through the 7-μm filter eventually became infected, an alternate source of introduction and spread of the pathogen was investigated. Aerial transmission of Phythium aphanidermatum by shore flies (Scatella stagnalis) was documented for the first time. Shore flies which were thought to feed only on blue-green algae and diatoms, also fed on cucumber roots colonized by the fungus. Ninety-seven percent of the first and second instar larvae, 20% of the pupae/third instar larvae, and 10% of adult flies carried mature oospores in their gut. Oospores excreted by larvae and adults were germinable. Phythium aphanidermatum was transmitted to healthy cucumber plants by naturally infested larvae and adult flies. Adult flies infested with P. aphanidermatum may account for pathogen introduction and spread within commercial greenhouse facilities.
8

Soil variability and geostatistical applications.

Zhang, Renduo. January 1990 (has links)
Statistical and geostatistical methods are utilized to investigate soil variability. Methodology includes block kriging, cokriging and simulations of random fields. The ramifications of the variability are numerous, including the effect on soil water, soil fertility, evapotranspiration, and crop yields. Block kriging can be used to estimate crop yields and infiltration rates on a large scale using small scale or point data. Results based on variograms and geostatistics are compared to the classical relationship developed by Smith in 1938, that the variance is reduced from V₁ to V₁/nᵇ as the support area increases from 1 to n plots. These results establish a firm theoretical basis for the variance within a finite domain as a function of sample support size. Applications include not only uniformity trials, but also measurement theory. Based on 20 data sets, indices of soil heterogeneity are derived. With these indices, optimal sample sizes and shapes can be determined. The ordinary kriging and cokriging estimators are investigated in order to examine their utilization. Soil moisture content and soil water retained at 1.5 MPa within the root zone are predicted by cokriging with surface moisture and texture as auxiliary variables. Compared with ordinary kriging, cokriging gave a significant improvement in terms of the average kriging variance and the sum of squared errors between the actual and the predicted values. With soil spectral properties and cokriging, soil texture is estimated successfully. Cokriging is also used for temporal variables and compared with a time invariant relationship. Recently-developed pseudo-cross variograms and cokriging are utilized to predict soil chemicals. The main advantage of this approach is that the computation of sample cross-variograms does not require that measured variables be sited at the same locations. Lastly, several simulation methods are studied. A new simulation procedure is developed and compared with other simulation methods, such as the Turning Bands Method. Conditional simulation is used to simulate random fields for soil water and reflectance.
9

The interaction of Thielaviopsis basicola (Berk. and Br.) Ferr. and Rhizoctonia solani Kuhn as pathogens of seedling cotton.

Chapman, Margaret Ann January 1990 (has links)
Soil inoculum density and the incidence of black root rot of cotton caused by Thielaviopsis basicola were monitored in two adjacent fields planted mid-April to Gossypium hirsutum 'Acala 1517' at Duncan, AZ (1160 m elev.). Forty soil cores (3.5 x 15 cm) were taken from the root zone and 80 plants were collected biweekly in the two fields from 5/7/87 to 9/28/87. The inoculum density (cfu/g air-dried soil) was determined by plating soil dilutions onto a selective medium. Disease severity was rated on a scale of 1 (slight cortical decay) to 4 (severe cortical decay). Mean inoculum density in Field 1 soil was 65 cfu/g soil and 20% of the seedlings were infected with a severity rating averaging 1.6. In Field 2 the inoculum density, percentage of infected plants, and disease rating were 225 cfu/g soil, 93, and 3.2, respectively. No cortical decay was noted after June 6 in either field. Yields were similar in both fields. Field and laboratory studies indicate that high disease incidence of black root rot caused by T. basicola results in reduced incidence of seedling disease caused by Rhizoctonia solani. For example, 1 mo after untreated seeds of G. barbadense 'Pima S-6' were planted into a cotton field in Coolidge, AZ with natural inoculum levels of 12 cfu/100 g soil and 225 cfu/g soil of R. solani and T. basicola, respectively, 98% of the plants were infected by T. basicola while only 2% were infected by R. solani. Eleven out of the 12 R. solani propagules were pathogenic to cotton. The same levels of inoculum, were added to autoclaved field soil in growth chambers at 18 C and 5200 lux light in four treatments. The first treatment, T. basicola alone, caused a 98% incidence of black root rot. Rhizoctonia solani alone resulted in a 38% incidence of disease, whereas inoculum of T. basicola and R. solani, together caused a 98% and 17% incidence of disease caused by T. basicola and R. solani, respectively. Simultaneous inoculations of 4-day-old G. hirsutum 'DP 90' seedlings on water agar plates with inoculum of T. basicola and R. solani resulted 5 days later in a significant decrease in infection by R. solani as compared to that in the seedlings inoculated with R. solani only.
10

Physiological and morphological maturation of the chicken pituitary.

Rahman, Zia-ur-. January 1990 (has links)
The present study reports the effects of MMI-treatment and castration on the maturation of the pituitary of White Leghorn cockerels. Body weights increase with age, but are significantly lower in the MMI-treated birds. Increases in total serum proteins and albumin in MMI-treated birds results in a much higher albumin/globulin ratio than that found in other birds. Castrated birds have the heaviest and MMI-treated birds have the smallest pituitaries. The increase in pituitary size appears to be due to cellular hypertrophy since the amount of DNA/gland is the same in castrated and control birds and is less in MMI-treated birds. Serum GH, TSH, T₃, and T₄ decreased with age in all groups, but were lowest in MMI-treated cockerels. Serum LH levels were highest in castrated birds and lowest in MMI-treated birds and serum prolactin highest in MMI-treated birds. Thyrotrophs, corticotrophs and lactotrophs were restricted to the cephalic lobe and somatotrophs occurred only in the caudal lobe. Luteotrophs occurred in both cephalic and caudal lobes of the pituitary. An increase in TSH, GH, PRL, ACTH, and LH cells occurred during maturation in both control and castrated birds but PRL, TSH and LH producing cells decreased in MMI-treated birds. Somatotrophs decreased in size with age as did their granules. Castrated birds had gonadotrophs that were significantly larger than those of normal or MMI-treated birds. This increase in gonadotroph size made a significant contribution to the postnatal increase in the size of the pituitary gland.

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