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Articles 2521 - 2550 of 2619

Full-Text Articles in Life Sciences

The Diachronic Study Of Animal Exploitation At Hesban: The Evolution Of A Research Project, Oystein S. Labianca Jan 1986

The Diachronic Study Of Animal Exploitation At Hesban: The Evolution Of A Research Project, Oystein S. Labianca

Faculty Publications

No abstract provided.

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Effect Of Adrenalectomy On In Vivo Glucose Metabolism In Insulin Resistant Zucker Obese Rats, Marjorie Freedman, Judith Stern, G. Reaven, C. Mondon Jan 1986

Effect Of Adrenalectomy On In Vivo Glucose Metabolism In Insulin Resistant Zucker Obese Rats, Marjorie Freedman, Judith Stern, G. Reaven, C. Mondon

Faculty Publications

Lean (Fa/?) and obese (fa/fa) Zucker rats were adrenalectomized (ADX) in order to assess the contribution of adrenal hormones to insulin resistance of the obese Zucker rat. Glucose utilization was measured using an insulin suppression test.Sham-operated obese rats gained almost twice as much weight as sham-operated lean littermates. However, body weight gain of ADX animals was comparable in both genotypes. It was significantly less than that of the respective sham-operated controls. Body weight differences can be accounted for almost entirely by a marked loss of adipose tissue.Although insulin resistance may be attributable to obesity in part, steroid hormones are thought …

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Clonal Selection Of Sugar Cane For Texas And Louisiana From A Common Germplasm Pool, Stephen Kresovich, Richard D. Breaux Dec 1985

Clonal Selection Of Sugar Cane For Texas And Louisiana From A Common Germplasm Pool, Stephen Kresovich, Richard D. Breaux

Faculty Publications

The sugar cane (a complex hybrid of Saccharum spp.) cultivar improvement program for the irrigated Lower Rio Grande Valley of Texas, initiated in 1961, has expanded greatly over the past 20 years. Initially, only 8 to 12 cultivars, selected from those previously released from commercial production in Louisiana or Florida, were screened annually for their production potential in the Lower Rio Grande Valley. The current introduction and screening program is more comprehensive utilizing 1) all clones advanced from the first to the second line trials at the U. S. Sugarcane Laboratory at Houma, Louisiana; 2) the advanced "CP" assignments from …

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Microbial Degradation Of The Leachable And Lignocellulosic Components Of Leaves And Wood From Rhizophora Mangle In A Tropical Mangrove Swamp, Ronald Benner, Robert E. Hodson May 1985

Microbial Degradation Of The Leachable And Lignocellulosic Components Of Leaves And Wood From Rhizophora Mangle In A Tropical Mangrove Swamp, Ronald Benner, Robert E. Hodson

Faculty Publications

Preparations of uniformly [14C] labeled mangrove leaves and specifically radiolabeled [14C-lignin] lignocelluloses and [14C -polysaccharide]lignocelluloses from mangrove leaves and wood were used in experiments to determine the microbial rates of mineralization of the leachable and lignocellulosic components of mangrove detritus in aerobic and anaerobic sediments of a tropical mangrove swamp. The bulk of the leachable fraction from mangrove leaves was mineralized relatively rapidly and was assimilated into microbial biomass with high efficiency (30 %). In contrast, rates of mineralization of the lignocellulosic component of mangrove leaves and wood were 10fold lower than mineralization rates …

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Primer On Forestry Investment, Thomas J. Straka, Steven H. Bullard, William F. Watson Jan 1985

Primer On Forestry Investment, Thomas J. Straka, Steven H. Bullard, William F. Watson

Faculty Publications

Most forest farmers know that growing timber is a good investment. Some forest farmers, however, and many new timberland investors may not fully understand the basic ingredients that make up a forestry investment. Like other ventures, forest farming involves costs and revenues, and rates of return can be calculated. These rates can be compared with interest rates for other investments, but forest farming is not exactly like your other investments. It has special qualities.

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What Is Your “Effective” Rate Of Reforestation Cost?, Steven H. Bullard, Thomas J. Straka Jan 1985

What Is Your “Effective” Rate Of Reforestation Cost?, Steven H. Bullard, Thomas J. Straka

Faculty Publications

If you are considering a reforestation investment, you should be concerned with its effective cost; ,that is, the cost of reforestation after considering interest arid timing of the tax savings and cost-share payments. Effective regeneration costs depend on your interest rate, marginal tax rate, and whether or not you receive assistance from a state or federal cost-share program.

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Maximizing Expected Profits In Competitive Bidding, Steven H. Bullard Jan 1985

Maximizing Expected Profits In Competitive Bidding, Steven H. Bullard

Faculty Publications

Forest products firms often buy much of their raw material through competitive bidding. The bidding process is vital to such companies, yet models are often used which merely help predict winning bids. Managers should consider expected returns from potential timber buying contracts-the product of profit and the prob· ability of realizing that profit. A general approach is summarized for maximizing expected profit in competitive bidding. For timber buying, profits are net returns minus stumpage costs. The probability of obtaining the profit is the probability a given bid will be accepted, and can be represented by a probability density function. The …

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Reforestation Timing Influences After-Tax Present Value Of Costs, Steven H. Bullard Jan 1985

Reforestation Timing Influences After-Tax Present Value Of Costs, Steven H. Bullard

Faculty Publications

Public Law 96-451 provides federal income tax incentives for reforestation. Taxpayers are allowed an investment tax credit in the year reforestation costs are incurred and deductions of one-fourteenth of reforestation costs on their first tax return, one-seventh on each of their next six tax returns, and one-fourteenth on their eighth tax return. The amount amortized is 95 percent of costs if a 10-percent tax credit is claimed or 100 percent of costs if an 8- percent credit is chosen. The credit and deductions can be applied for up to $10,000 of reforestation costs each year.

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Long Term Response Of Loblolly Pine To Colloidal Phosphate, M. Victor Bilan, Marcey A. Gillespie Jan 1985

Long Term Response Of Loblolly Pine To Colloidal Phosphate, M. Victor Bilan, Marcey A. Gillespie

Faculty Publications

Three or six ounces of colloidal phosphate were applied either in planting hole or on soil surface while planting loblolly pine in East Texas. Combination of phosphate in the planting hole with NK on soil surface increased diameter growth for four years and the height growth for 18 years after planting.

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Survival Of Pines On Droughty Soils: Two-Year Results, James Kroll, William C. Deauman, C. Darwin Foster, David Kulhavy, W. David Tracey Jan 1985

Survival Of Pines On Droughty Soils: Two-Year Results, James Kroll, William C. Deauman, C. Darwin Foster, David Kulhavy, W. David Tracey

Faculty Publications

Three species of pines (loblolly, slash and longleaf) were planted with four treatments (loblolly and slash = bareroot, clay dip slurry and TerrasorH ; longleaf = containerized) to test survival on droughty, typic quartzipsamments soils. At the end of the first season, survival~s significantly better for the containerized longleaf and Terrasoro treated loblolly pine (81 and 85%) followed by untreaRed loblolly pine (51%), clay-treated loblolly (50%), then Terrasorb treated slash (48%), untreated slash (41%) and clay-treated slash (36%). At the e~of the second growing season, longleaf had 56% survival, Terrasor~ treated loblolly (51%), clay-dip slurry loblolly (31.9%), Terrasoro treated slash …

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Establishment Of Permanent Growth And Yield Plots In Loblolly And Slash Pine Plantations, J. David Lenhart, Ellis V. Hunt Jr., Jock A. Blackard Jan 1985

Establishment Of Permanent Growth And Yield Plots In Loblolly And Slash Pine Plantations, J. David Lenhart, Ellis V. Hunt Jr., Jock A. Blackard

Faculty Publications

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.

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Evaluating Landowner Assistance Programs And Other Wood Procurement Options, Gary D. Kronrad, C. Franklin, J.E. De Steiquer Jan 1985

Evaluating Landowner Assistance Programs And Other Wood Procurement Options, Gary D. Kronrad, C. Franklin, J.E. De Steiquer

Faculty Publications

A major activity of forest industry is supplying their mills with wood. There are four options for wood procurement: fee land, lease land, landowner assistance programs, and open market. The task of the corporate planner is to allocate the limited budget among these options in such a way that the needed volumes of wood are procured at the least cost. A methodology has been developed to aid in this capital budget in process and has been incorporated in an easy-to-use computer program.

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Estimating Optimal Thinning And Rotation For Mixed-Species Timber Stands Using A Random Search Algorithm, Steven H. Bullard, Hanif D. Sherali, W. David Klemperer Jan 1985

Estimating Optimal Thinning And Rotation For Mixed-Species Timber Stands Using A Random Search Algorithm, Steven H. Bullard, Hanif D. Sherali, W. David Klemperer

Faculty Publications

The problem of optimal density over time for even-aged, mixed-species stands is formulated as a nonlinear-integer programming problem with numbers of trees cut by species and diameter class as decision variables. The model is formulated using a stand-table projection growth model to predict mixed-speciesg rowth and stand-structureO. ptimal thinning and final harvest age are estimated simultaneously using heuristic random search algorithms. For sample problemsw ith two speciesr, andom searchm ethodsp rovide near-optimalc uttings trategiesw ith very little computer time or memory. Optimal solutions are estimated for problems with eight initial species/diameter class groups, projected for up to three discrete growth …

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Financial Maturity Of Timber And Maximum Net Present Values, Steven H. Bullard Jan 1985

Financial Maturity Of Timber And Maximum Net Present Values, Steven H. Bullard

Faculty Publications

Simple financial maturity guidelines recommend harvesting timber when its rate of value growth becomes less than or equal to the highest rate that can be earned in other investments of equal risk. Several authors have shown that fin ancial maturity guides are consistent with maximizing economic c riteria such as net present va lue , but their results are sometimes accepted by fore sters and land managers without being fully understood. In this article , financial maturity guides are derived in a way that is easily understood, simply by maximizing the present value of all future net income.

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Business Aspects Of The Mid-South Forest Economy, Steven H. Bullard, Thomas J. Straka Jan 1985

Business Aspects Of The Mid-South Forest Economy, Steven H. Bullard, Thomas J. Straka

Faculty Publications

Timber resources and related economic activity are substantial in the Mid-South states of Tennessee Alabama Mississippi, Louisiana, and Arkansas. Most of u; are awar~ that timber is an important aspect of our regional economy. We observe many stands of timber and often see it being harvested and transported to shipping points and manuf~cturing facilities. Many, however, do not fully appreoate the absolute size of the Mid-South's forest resources, nor their relative importance to states within the region. The Mid-South forest economy is described in two sections: (1) forest resources in general and (2) timber manufacturing or processing. Value added and …

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Some Plant Leaves Have Orientation-Dependent Epr And Nmr Spectra, Douglas C. Mccain, Ted C. Selig, Govindjee, John L. Markley Feb 1984

Some Plant Leaves Have Orientation-Dependent Epr And Nmr Spectra, Douglas C. Mccain, Ted C. Selig, Govindjee, John L. Markley

Faculty Publications

Proton nuclear magnetic resonance (1H NMR) spectra of leaves from 50 plant species were obtained at a spectrometer frequency of 470 MHz. Water present in leaf samples gives rise to characteristic spectral patterns. Most species show only one broad 1H NMR peak; however, the leaves of some plants display complex, orientation-dependent spectra in which a common three-line pattern is discerned. The pattern varies with the angle between the leaf surface and the external magnetic field. Proton relaxation measurements show the presence of at least two water compartments in the leaves. The compartments are responsible for different components …

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An Approach For Projecting Mixed-Species Forest Growth And Mortality, Steven H. Bullard Jan 1984

An Approach For Projecting Mixed-Species Forest Growth And Mortality, Steven H. Bullard

Faculty Publications

Mixed-species forests are common throughout the United States and growth and yield models are needed which reflect complex interrelationships. A stand-table projection approach with upgrowth and mortality components is presented for modeling growth and development in such forests. The method involves concepts previously used to model mixed-species diameter growth, in the upgrowth component of the projection system. Tentative equation forms arc presented to help clarify the general approach.

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Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Infestation Rates Related To Site And Stand Characteristics In Nacogdoches County, Texas, David Kulhavy, Richard N. Conner, Mark White Jan 1984

Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Infestation Rates Related To Site And Stand Characteristics In Nacogdoches County, Texas, David Kulhavy, Richard N. Conner, Mark White

Faculty Publications

Twenty-two pine stands with a variety of site and stand characteristics and management strategies were analyzed using discriminant analysis to determine factors which influence Nantucket pine tip moth infestations. A whole-tree sequential sampling scheme designed to estimate absolute infestation rates (±5%) was used. An 8% infestation rate was used as the dividing line between high and low tip moth infestations. A sequential sampling program was used in the field to estimate populations. Absolute infestation rates (P ± 5%), were obtained through random selection of pines for whole-tree sampling. Four equations were developed which gave 91% correct classification of initial …

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A Case For Heuristic Optimization Methods In Forestry, Steven H. Bullard, W. David Klemperer Jan 1984

A Case For Heuristic Optimization Methods In Forestry, Steven H. Bullard, W. David Klemperer

Faculty Publications

With rising competition for scarce resources, forest managers are increasingly concerned with estimating optimal solutions to complex problems. Heuristic procedures are often useful in solving such problems.

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Estimation Of Body Density In Adolescent Athletes, W G. Thorland, G O. Johnson, G D. Tharp, T J. Housh, C J. Cisar Jan 1984

Estimation Of Body Density In Adolescent Athletes, W G. Thorland, G O. Johnson, G D. Tharp, T J. Housh, C J. Cisar

Faculty Publications

National samples of 141 male and 133 female highly-trained adolescent athletes were studied to derive anthropometric-based equations predicting body density. Anthropometric measures included skinfold thicknesses at seven sites, circum- ferences at 14 sites, and diameters at nine sites. Criterion measures of body density were determined by underwater weighing with corrections for residual lung vol- ume based on the oxygen dilution method. Variable selection procedures included factor analysis followed by forward-stepping regression and polynomial analysis. For both the male and female samples, two quadratic equations utilizing either the sum of three or seven skinfold measures were derived. Within the male sample, …

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Promoting Soft Mast For Wildlife In Intensively Managed Forests, John J. Stransky, John H. Roese Jan 1984

Promoting Soft Mast For Wildlife In Intensively Managed Forests, John J. Stransky, John H. Roese

Faculty Publications

The fruit of woody plants is important as food for wildlife (Martin et al. 1951, Lay 1965). The relation of fruit production to southern forest stand conditions has been explored in only a few studies. Fruit production is greater in forest clearings than in closed forest stands (Lay 1966, Elalls and Alcaniz 1968). In Georgia slash pine (Pinus elliottii) plantations, fruit yields of shrubs are greatest in 4-yeas-old stands, and soil disturbance in site preparation greatly reduces fruit yields (Johnson and Landers 1978). Total fruit production is greatest in 5-year-old bedded loblolly pine (P. taeda) plantations …

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Mississippi’S Softwood Timber Potential: Private Nonindustrial Influences, Steven H. Bullard, G. H. Weaver, Willem W. S. Van Hees Jan 1984

Mississippi’S Softwood Timber Potential: Private Nonindustrial Influences, Steven H. Bullard, G. H. Weaver, Willem W. S. Van Hees

Faculty Publications

Mississippi's long-run softwood timber potential was estimated for three input situations under a common set of economic and biological assumptions. Economic goals for sustained pine production were estimated using the computer program GASPLY with no restrictions, with private nonindustrial upland hardwoods excluded from type conversion and with private nonindustrial lands excluded from active forest management altogether. Estimated price-quantity equilibria ranged from $301 per thousand cubic feet (MCF) and 966 million cubic feet (MMCF) in the unrestricted case, to $1,226/MCF and 479 MMCF in the example with passive private nonindustrial management. Widely diffel'ing potential goals for pine product-ion highlight the degree …

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Root Diseases And Blister Rust Associated With Bark Beetles (Coleoptera: Scolytidae) In Western White Pine In Idaho, David Kulhavy, A.D. Partridge, R.W. Stark Jan 1984

Root Diseases And Blister Rust Associated With Bark Beetles (Coleoptera: Scolytidae) In Western White Pine In Idaho, David Kulhavy, A.D. Partridge, R.W. Stark

Faculty Publications

Root systems of western white pine, Pinus montieola Douglas, were excavated with explosives and examined for pathogens. Data were also recorded on portions of the crown killed by blister rust caused by Cronartium ribieola Fisch. Statistical tests revealed a significant association between the bark beetles Dendroetonus ponderosae Hopkins and Pityogenes fossifrons (LeConte), and the root pathogen Armillariella mellea. (Vah!. ex Fr.) Karst and between beetles and all root diseases. Ninety-two percent of the trees attacked by bark beetles had root diseases, and 97% had either root diseases or blister rust. A discriminant analysis correctly classified 88% of the sample trees …

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Estimating Infestation Rates Of The Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Through Sequential Sampling, David Kulhavy, Paul C. Johnson, Bernard Andersen Jan 1984

Estimating Infestation Rates Of The Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Through Sequential Sampling, David Kulhavy, Paul C. Johnson, Bernard Andersen

Faculty Publications

Sequential sampling to estimate proportion from a binomially distributed population was used to estimate apparent and actual infestation rates of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), on loblolly, Pinus taeda, and shortleaf pine, P. echinata. Populations of R. frustrana, as measured by infested tips, increased from the overwintering generation through the second generation (July), then decreased rapidly for P. echinata. Populations of R. frustrana continued to increase through the season in P. taeda. Tip moth infestations were concentrated in the top one-half of the tree.

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Effect Of A Prescribed Fire On Herbage Production In Southwestern Ponderosa Pine On Sedimentary Soils, Brian P. Oswald, W. Wallace Covington Jan 1984

Effect Of A Prescribed Fire On Herbage Production In Southwestern Ponderosa Pine On Sedimentary Soils, Brian P. Oswald, W. Wallace Covington

Faculty Publications

An area burned by prescription in 1977 and a nearby unburned area were measured in 1974 and 1980 to determine effects of the burn on herbage and forage production. Herbage production on the burned area increased significantly in 1980 over its 1974 level, in addition to being greater than the 1980 control production. However, the proportion of forage production to total herbage production in 1980 on the burned area decreased after the burn, and was significantly less than the control area forage production. This reduction in forage production can be attributed to the increase of nonforage species, notably bracken fern. …

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Thinning Optimization In Mixed-Species Forests, Steven H. Bullard, W. David Klemperer Jan 1984

Thinning Optimization In Mixed-Species Forests, Steven H. Bullard, W. David Klemperer

Faculty Publications

An approach is summarized for estimating optimal thinning and final harvest age for existing, mixed-species stands. The method involves stand-table projection with upgrowth and mortality equations, formulated as an integer-nonlinear programming problem. Random search methods are proposed for estimating optimal cutting prescriptions. Such solution methods warrant further study in forestry, since their use enables broad application of stand-specific modeling results.

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Rearrangement Of The Keratin Cytoskeleton After Combined Treatment With Microtubule And Microfilament Inhibitors, Loren W. Knapp, W. Michael O'Guin, Roger H. Sawyer Dec 1983

Rearrangement Of The Keratin Cytoskeleton After Combined Treatment With Microtubule And Microfilament Inhibitors, Loren W. Knapp, W. Michael O'Guin, Roger H. Sawyer

Faculty Publications

In addition to containing microtubule and microfilament systems, vertebrate epithelial cells contain an elaborate keratin intermediate-filament cytoskeleton. Little is known about its structural organization or function. Using indirect immunofluorescence microscopy with an antikeratin antiserum probe, we found that destabilization of microtubules and microfilaments with cytostatic drugs induces significant alterations in the cytoskeletal organizationof keratin filaments in HeLa and fetal mouse epidermal cells. Keratin filament organizationwas observed to undergo a rapid (1-2 h) transition from a uniform distribution to an open lattice of keratin fibers stabilized by membrane-associated focal centers . Since addition of any one drug alone did not elicit …

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Isolation Of A Bacterium Capable Of Degrading Peanut Hull Lignin, Thomas J. Kerr, Robert D. Kerr, Ronald Benner Nov 1983

Isolation Of A Bacterium Capable Of Degrading Peanut Hull Lignin, Thomas J. Kerr, Robert D. Kerr, Ronald Benner

Faculty Publications

No abstract provided.

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The Potential Of Girdled And 2,4-D-Injected Southern Red Oaks As Woodpecker Nesting And Foraging Sites, Richard N. Conner, James C. Kroll, David L. Kulhavy Aug 1983

The Potential Of Girdled And 2,4-D-Injected Southern Red Oaks As Woodpecker Nesting And Foraging Sites, Richard N. Conner, James C. Kroll, David L. Kulhavy

Faculty Publications

Comparisons of extent of decay in southern red oaks (Quercus falcate Michx.) revealed that trees injected with 2.4-D decayed sooner than girdled trees. Internal examinations of treated trees revealed that girdling and injection permitted growth of heartwood-and sapwood-decaying fungi a condition necessary for woodpecker nest cavity excavation. As a result of the delayed decay, girdling produces better woodpecker habitat in southern red oak. Girdled southern red oaks remain standing longer for woodpeckers to use for foraging and nesting sites. Number of snags required to support various percentages of woodpecker population maximums are presented.

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Mixed-Hardwood Thinning Optimization, Steven H. Bullard Jan 1983

Mixed-Hardwood Thinning Optimization, Steven H. Bullard

Faculty Publications

Upland hardwood forest types are .by far the most widespread in the United States. Stands of the oak-hickory forest type alone include 109 million acres, 23 percent of the Nation's commercial timberland (U.S. Forest Service 1982) . Many even-aged upland hardwood stands developed on nonindustrial private lands through hardwood invasion after pine stands were harvested. In 1973, half of the hardwood timber in the South was determined to be on upland sites which formerly supported pine stands (Murphy and Knight 1974). Many nonindustrial private landowners passively permit the biologically better adapted hardwoods to increase after the harvest of pines. These …

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