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Articles 2371 - 2400 of 2622

Full-Text Articles in Life Sciences

Optimization Approach To The Treatment Of Open Boundary-Conditions, I. Shulman, James K. Lewis May 1995

Optimization Approach To The Treatment Of Open Boundary-Conditions, I. Shulman, James K. Lewis

Faculty Publications

A solution to an optimization problem is developed that deals with minimizing a measure of difference between the values of observed and predicted variables at an open ocean boundary. Minimization is based on the change of the flux of energy through the open boundary. It is shown that many of the longwave radiation conditions that are commonly used in ocean modeling can be derived using this optimization criteria. However, the minimization process is seen to produce a modification of these radiation conditions in that they are multiplied by a coefficient, which allows the conditions to adapt to a change in …

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Community Metabolism And Nutrient Cycling In The Mississippi River Plume: Evidence For Intense Nitrification At Intermediate Salinities, Joseph D. Pakulski, Ronald Benner, Rainer Amon, Brian Eadie, Terry Whitledge Feb 1995

Community Metabolism And Nutrient Cycling In The Mississippi River Plume: Evidence For Intense Nitrification At Intermediate Salinities, Joseph D. Pakulski, Ronald Benner, Rainer Amon, Brian Eadie, Terry Whitledge

Faculty Publications

Community respiration, net nutrient fluxes and heterotrophic bacterial production were investigated in the Mississippi River (USA) plume during May 1992 using dark bottle incubations of unfiltered water. Highest rates of community O2 consumption and dissolved inorganic carbon regeneration were observed at intermediate (10 to 27%0) plume salinities. Plume surface 02 consumption rates were 2- to 4-fold greater than rates reported previously during the summer and winter. Heterotrophic bacterial production ([3H]-leucine incorporation) was also highest at intermediate salinities and 2- to 4-fold greater than rates reported from other seasons. Net regeneration of NH4+ …

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Chi Gong--An Exercise For Internal Health, G. Chen, Shirley H. M. Reekie Jan 1995

Chi Gong--An Exercise For Internal Health, G. Chen, Shirley H. M. Reekie

Faculty Publications

No abstract provided.

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Foraging Ecology Of The Mangrove Salt Marsh Snake, Nerodia Clarkii Compressicauda: Effects Of Vegetational Density [Abstract], Stephen J. Mullin, Henry R. Mushinsky Jan 1995

Foraging Ecology Of The Mangrove Salt Marsh Snake, Nerodia Clarkii Compressicauda: Effects Of Vegetational Density [Abstract], Stephen J. Mullin, Henry R. Mushinsky

Faculty Publications

No abstract provided.

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Association Of Mouse Fibrinogen-Like Protein With Murine Hepatitis Virus-Induced Prothrombinase Activity, Rebecca D. Parr, Laisum Fung, Jeffrey Reneker, Nancy Myers-Mason, Julian L. Leibowitz, Gary Levy Jan 1995

Association Of Mouse Fibrinogen-Like Protein With Murine Hepatitis Virus-Induced Prothrombinase Activity, Rebecca D. Parr, Laisum Fung, Jeffrey Reneker, Nancy Myers-Mason, Julian L. Leibowitz, Gary Levy

Faculty Publications

Previously, we demonstrated induction of a unique macrophage prothrombinase during infection of BALB/cJ mice by mouse hepatitis virus strain 3 (MHV-3). By immunologic screening, a clone representing this prothrombinase was isolated from a cDNA library and sequenced. The sequence identified this clone as representing part of a gene, musfiblp, that encodes a fibrinogen-like protein. Six additional clones were isolated, and one clone, p11-3-1, encompassed the entire coding region of musfiblp. Murine macrophages did not constitutively express musfiblp but, when infected with MHV-3, synthesized musfiblp-specific mRNA. musfiblp mRNA induction was earlier and significantly greater in BALB/cJ than A/J …

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Molecular Mimicry Between Fc Receptor And S Peplomer Protein Of Mouse Hepatitis Virus, Bovine Corona Virus, And Transmissible Gastroenteritis Virus [Abstract], Emilia L. Oleszak, Jacek Kuzmak, Brenda Hogue, Rebecca D. Parr, Ellen W. Collisson, L. Scott Rodkey, Julian L. Leibowitz Jan 1995

Molecular Mimicry Between Fc Receptor And S Peplomer Protein Of Mouse Hepatitis Virus, Bovine Corona Virus, And Transmissible Gastroenteritis Virus [Abstract], Emilia L. Oleszak, Jacek Kuzmak, Brenda Hogue, Rebecca D. Parr, Ellen W. Collisson, L. Scott Rodkey, Julian L. Leibowitz

Faculty Publications

No abstract provided.

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Hardwoods In North Mississippi: Resource Information From Two Forest Surveys, Steven H. Bullard, Clay Robertson, Joshua Idassi, Joanne L. Faulkner Jan 1995

Hardwoods In North Mississippi: Resource Information From Two Forest Surveys, Steven H. Bullard, Clay Robertson, Joshua Idassi, Joanne L. Faulkner

Faculty Publications

The USDA Forest Service periodically conducts forest surveys for Mississippi and other states. Survey results for a 26-county area designated as "North Mississippi" were most recently published in late 1993. We compared the hardwood acreages, volume, growth, removals and other values to the survey results published in 1987 for this region, and several significant results are evident:

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Root Growth Potential And Field Survival Of Container Loblolly Pine Seedlings Fall Fertilized With Nitrogen, Hans Michael Williams, David B. South Jan 1995

Root Growth Potential And Field Survival Of Container Loblolly Pine Seedlings Fall Fertilized With Nitrogen, Hans Michael Williams, David B. South

Faculty Publications

Two studies investigated the effects of fall nitrogen fertilizer applications on the root growth potential (RGP) and field performance of container loblolly pine seedlings (Pinus taeda L.). The seedlings were sampled at 4 chilling levels ranging from 100 to 550 hours (0 to 8' C). Seedlings propagated for the first study may have had a hidden nutrient deficiency and therefore the fall diammonium phosphate (DAP) application at rates of 202 kg N/ha and 67 kg N/ha increased RGP 43% and 32%, respectively. The growing season mineral fertilizer application rate was increased in the second study which may explain why nitrogen …

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Clearcutting And Shearing On A Saline Soil In East Texas: Impacts On Soil Physical Properties, Chang Mingteh, Alexander K. Sayok, Kenneth G. Watterson Jan 1995

Clearcutting And Shearing On A Saline Soil In East Texas: Impacts On Soil Physical Properties, Chang Mingteh, Alexander K. Sayok, Kenneth G. Watterson

Faculty Publications

Soil samples, or in-situ measurements, were collected at seven occasions and at six depths to study the Impact of three forest conditions on soil physical properties of a saline soil in E. Texas. Soil bulk density, CW. of silt plus clay at the surface horizons, soil water content, soil water retention, and depth to groundwater Increased following intensive site preparation. Differences in these properties between the commercial clearcuttlng and undisturbed forest were small. The wet soil conditions created in the Intensive preparation site are not likely to be responsible for the failure of artificial pine regeneration. In areas where site …

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Interpretation And Emotion: Making Heritage Live, Paul Risk Jan 1995

Interpretation And Emotion: Making Heritage Live, Paul Risk

Faculty Publications

No abstract provided.

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Evaluation Of Pilot Interpretive Program For National Forest Recreation Areas In East Texas, Michael Legg, Ronda Sutphen Jan 1995

Evaluation Of Pilot Interpretive Program For National Forest Recreation Areas In East Texas, Michael Legg, Ronda Sutphen

Faculty Publications

Visitor surveys were conducted at Ratcliff and Double lake Recreation Areas to evaluate visitor characteristics and effectiveness of interpretive services as a management tool. Two hundred eighty-two campers completed the survey. Dat8 from both recreation areas were analyzed and compared in order to determine significant differences between visitors in recreation area and also between visitors who attended or did not attend interpretive programs.

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Wilderness Planning: A Case Study In Dispute Resolution, Michael Legg, Marlene Rebori Tull Jan 1995

Wilderness Planning: A Case Study In Dispute Resolution, Michael Legg, Marlene Rebori Tull

Faculty Publications

Local landowners and environmental groups have historically disputed with the USDA National Forest Service in Texas over wilderness management issues such as wild and prescribed fire and management of the southern pine beetle (Dendroctonusfrontalis). To help diffuse polarization and open lines of communication between agency personnel and the general public, the theory of transactive planning was applied with the LAC process on two wilderness areas. Data collection consisted of: 1) participant observation; 2) issue-evaluation surveys; 3) process-evaluation surveys; and 4) exit interviews. Results indicate the planning process aids in dispute resolution by reducing antagonistic relationships and fostering public consensus in …

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Growth Rate As A Function Of Food Consumption In Hatchling Sceloporus Virgatus (Sauria: Iguanidae), Geoffrey R. Smith Jan 1995

Growth Rate As A Function Of Food Consumption In Hatchling Sceloporus Virgatus (Sauria: Iguanidae), Geoffrey R. Smith

Faculty Publications

No abstract provided.

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New Optical Cell Design For Laser Flash Photolysis Studies In Supercritical Fluids, Steven R. Goates, Milton L. Lee, Qin Ji, Edward M. Eyring, Rudi Van Eldik, Kedika Bal Reddy Jan 1995

New Optical Cell Design For Laser Flash Photolysis Studies In Supercritical Fluids, Steven R. Goates, Milton L. Lee, Qin Ji, Edward M. Eyring, Rudi Van Eldik, Kedika Bal Reddy

Faculty Publications

A high-pressure optical cell has been designed that achieves an effective separation between the chemical sample and the pressurizing medium and system. This design limits possible sample contamination and catalytic effects under supercritical fluid sample conditions. Laser flash photolysis experiments were carried out on molybdenum hexacarbonyl dissolved in supercritical CO2. The thermal ring closure reaction of the species Mo(CO)5L, where L is 2,2- bipyridine was found to proceed at rates comparable to those measured previously in liquid benzene or toluene. Much larger activation volumes were found for the reaction in supercritical CO2 than in liquid toluene.

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Processing Of Song Signals In The Cricket And Its Hormonal Control, Gordon Atkins, John Stout Dec 1994

Processing Of Song Signals In The Cricket And Its Hormonal Control, Gordon Atkins, John Stout

Faculty Publications

SYNOPSIS. Phonotaxis by female crickets to the calling song of males, is an important model for investigating the neural basis of auditory behavior. Recent advances make it possible to explain some components of this behavior and its hormonal control, at the level of identified neurons and molecular expression within those neurons. Tonotopically arranged afferents from the cricket's ear, project to local and intersegmental prothoracic interneurons. Bilateral processing of signals and some temporal-pattern specific processing occurs in the prothoracic ganglion and influences acoustic information that is sent to the brain via ascending interneurons that are demonstrably involved in phonotaxis. High, low …

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Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner Nov 1994

Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner

Faculty Publications

Rates of benthic denitrification, oxygen consumption and nutrient regeneration were measured during winter, spring and summer in Galveston Bay (Texas, USA) sediments. Denitrification ranged from 0 to 47 µmol N2 m-2 h-1 with maximal rates generally occurring in the summer and the upper estuary. Oxygen consumption rates ranged from 38 µmol O2 m-2 h-1 in the winter to 353 µmol O2 m-2 h-1 in the summer and were correlated with denitrification rates. Variations in bay water temperature accounted for 52 % of the variability associated with denitrification rates whereas only 28% …

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Semiclassical Quantization Of A Nonintegrable System: Pushing The Fourier Method Into The Chaotic Regime, Karl Sohlberg, Randall B. Shirts Nov 1994

Semiclassical Quantization Of A Nonintegrable System: Pushing The Fourier Method Into The Chaotic Regime, Karl Sohlberg, Randall B. Shirts

Faculty Publications

Semiclassical Einstein–Brillouin–Keller (EBK) quantization of the nonintegrable Hénon–Heiles Hamiltonian succeeds using the Fourier transform method of Martens and Ezra. Two innovations are required for this success: (1) the use of tunneling corrected quantizing actions obtained from an approximate, one-dimensional Hamiltonian and (2) exploitation of intermediate-time approximate quasiperiodicity or "vague tori'' wherein the Fourier transform of chaotic motion over 10–100 vibrational periods allows the determination of frequencies and amplitudes which approximate motion during the time interval. Approximate tori, actions, and EBK energy levels are then straightforward. We use an interpolation method to smooth over small resonance zones that are not expected …

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Contextual Interference Effects In The Acquisition And Retention Of Motor Tasks By Individuals With Mild Mental Handicaps, William J. Vincent, Mary A. Painter, Kathleen B. Inman Oct 1994

Contextual Interference Effects In The Acquisition And Retention Of Motor Tasks By Individuals With Mild Mental Handicaps, William J. Vincent, Mary A. Painter, Kathleen B. Inman

Faculty Publications

The effects of contextual interference on motor skill acquisition and retention were examined in 24 subjects (mean age 13.9 years) with mild mental retardation and 24 chronologically age-matched subjects (mean age 13.11 years) with no disabilities. Subjects from each group were assigned randomly to either a blocked or a random practice schedule. All subjects performed 15 practice trials for each of three different beanbag throwing tasks, 45 trials total. Following a 10-min filled retention interval, 2 trials of each throw (6 total) were performed in a random order by all subjects. Accuracy scores were measured as absolute error from the …

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Biochemical And Histological Changes During Ovarian Development Of Cobia, Rachycentron Canadum, From The Northern Gulf Of Mexico, Patricia M. Biesiot, Robert E. Caylor, James S. Franks Oct 1994

Biochemical And Histological Changes During Ovarian Development Of Cobia, Rachycentron Canadum, From The Northern Gulf Of Mexico, Patricia M. Biesiot, Robert E. Caylor, James S. Franks

Faculty Publications

Female cobia, Rachycentron canadum, were sampled on their spawning grounds in the Northern Gulf of Mexico to study changes in proximate analysis (protein, lipid, carbohydrate, and ash) of the ovaries during gonadal maturation. Four major stages of oocyte development were studied: stage 1, previtellogenesis; stage 2, vitellogenesis; stage 3, final maturation; and stage 4, postovulation. Cobia are multiple spawning fish; therefore, ovaries engaged in a sequential round of oogenesis were distinguished as stages 1' and 2'. Protein was the major constituent of cobia ovaries and its contribution of cobia ovaries and its contribution remained fairly constant (49-55% fo the …

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The Structure And Dynamics Of The Cs2 Molecular Ion, Karl Sohlberg, Chan Yibai Sep 1994

The Structure And Dynamics Of The Cs2 Molecular Ion, Karl Sohlberg, Chan Yibai

Faculty Publications

Several common elementary methods of computing molecular properties, prerequisite to molecular dynamics studies, are tested for their validity for CS+2. Judged sufficiently accurate, these methods are then used to aid in investigating the collisionally activated dissociation of CS+2 upon impact with xenon. Rice–Ramsperger–Kassel–Marcus (RRKM) unimolecular decay rate calculations are presented and compared to experimental studies employing collisional activation. RRKM theory is shown to reproduce the experimental results for collision energies near threshold. When corrected for vibrational anharmonicity, the RRKM calculation shows agreement with the experimental results over a slightly wider range of energies. A discussion is given on the applicability …

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Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher May 1994

Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher

Faculty Publications

The purpose of this study was to further our understanding of the role of particle-associated bacteria in phytoplankton degradation in the Chesapeake Bay, USA, and to identify environmental parameters that control production by free and particle-associated bacteria. Surface and bottom waters at 10 stations along the length of the Bay were sampled over a 2 yr period. Samples were analyzed for temperature, salinity, chlorophyll, phaeophytin, particulate protein, thymidine incorporation (an estimate of bacterial growth rate), and bacterial total direct counts. Results demonstrated that freeliving bacteria were responsible for most of the total bacterial production, which was correlated with temperature and …

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The Herpes Simplex Virus Thymidine Kinase Gene As A Conditional Negative-Selection Marker Gene In Arabidopsis Thaliana, Mihály Czakó, László Márton Mar 1994

The Herpes Simplex Virus Thymidine Kinase Gene As A Conditional Negative-Selection Marker Gene In Arabidopsis Thaliana, Mihály Czakó, László Márton

Faculty Publications

The human herpes simplex virus thymidine kinase type 1 gene (HSVtk) acts as a conditional lethal marker in mammalian cells. The HSVtk-encoded enzyme is able to phosphorylate certain nucleoside analogs (e.g. ganciclovir, an antiherpetic drug), thus converting them to toxic DNA replication inhibitors. The utility of HSVtk as a conditional negative-selection marker was explored in Arabidopsis thaliana (L.) Heynh. HSVtk was introduced into Arabidopsis by Agrobaderium-mediated transformation. Transgenic plants were morphologically indistinguishable from wild type and exhibited normal fertility. Canciclovir at lO-5to 10-4 M drastically reduced shoot regeneration on transgenic, HSVtk* root explants …

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Comparison Of Dietary Overlap Between Allopatric And Sympatric Geckos, Paul D. Klawinski, R. Kathryn Vaughan, Daniel Saenz, William Godwin Jan 1994

Comparison Of Dietary Overlap Between Allopatric And Sympatric Geckos, Paul D. Klawinski, R. Kathryn Vaughan, Daniel Saenz, William Godwin

Faculty Publications

Two gecko species, Hemidactylus turcicus and Cyrtopodion scabrum, have been introduced into the Port of Galveston, Texas. While H. turcicus has been established for a longer period of time, the relatively recent introduction of C. scabrum near the entrance of the Port has apparently led to the displacement of H. turcicus in that area. This has resulted in a distribution in which the two populations’ are largely allopatric except for a narrow band of sympatry at the periphery of each of their ranges. We examined stomach contents of both species in allopatry and sympatry in order to determine if …

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A Performance Evaluation Of Edging And Trimming Operations In U.S. Hardwood Sawmills, Tony El-Radi, Steven H. Bullard, Philip Steele Jan 1994

A Performance Evaluation Of Edging And Trimming Operations In U.S. Hardwood Sawmills, Tony El-Radi, Steven H. Bullard, Philip Steele

Faculty Publications

Edger and trimmer operators must make constant decisions in short time periods on the amount of materials to remove from boards produced in the sawmill. Their decisions directly affect the total volume, grade, and value of the boards, and they therefore directly affect the total value of lumber produced. In recent years, many softwood sawmills have installed computer controlled edgers and trimmers with scanners and optimizers to achieve higher recovery rates. Before similar, relatively expensive, technologies can be seriously evaluated for the hardwood industry, however, the current performance of edging and ·trimming operations must be known. Using a sample of …

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Growth Models Of Loblolly And Shortleaf Pine Red-Cockaded Woodpeckers Nesting Trees, W. D. Hacker, W. G. Ross, David Kulhavy Jan 1994

Growth Models Of Loblolly And Shortleaf Pine Red-Cockaded Woodpeckers Nesting Trees, W. D. Hacker, W. G. Ross, David Kulhavy

Faculty Publications

No abstract provided.

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Characterizing Fusiform Rust Incidence And Distribution In East Texas, J. David Lenhart, Gary D. Kronrad, A. Gordon Holley, T.G. Gregoire Jan 1994

Characterizing Fusiform Rust Incidence And Distribution In East Texas, J. David Lenhart, Gary D. Kronrad, A. Gordon Holley, T.G. Gregoire

Faculty Publications

Three measurement cycles were completed on an extensive network of loblolly( Pinus taeda L.) pine and slash (Pinus elliottii Engelm.) pine plots in industrial plantations throughout East Texas in 1984, 1987, and 1990.Because the incidence of fusiform rust caused by Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme had been recorded at each measurement, it is possible to characterize the temporal and geographic distribution of fusiform rust among these industrial pine plantations in East Texas. Average rust incidence for each species by two year age classes is presented. For loblolly pine, there is no apparent change in overall average …

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Characterization Of An Old-Growth Bottomland Hardwood Wetland Forest In Northeast Texas: Harrison Bayou, Laurence C. Walker, Thomas Brantley, Virginia Burkett Jan 1994

Characterization Of An Old-Growth Bottomland Hardwood Wetland Forest In Northeast Texas: Harrison Bayou, Laurence C. Walker, Thomas Brantley, Virginia Burkett

Faculty Publications

Most wetland losses in the southern region over the past 200 years have occurred in bottomland hardwood forests. By 1980 the original extent of palustrine bottomland in Texas had been reduced by 63%, from roughly 16 to 6 million acres. Additional losses have occurred during more recent years as a result of conversion to agriculture and timber harvests; these factors and the need to supply new hardwood chip mills in the region pose a potential threat to the remaining hardwood resource. The Harrison Bayou watershed in northeast Texas contains one of the few relatively undisturbed bottomland hardwood wetland forests in …

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Forval A Software Package For Forestry And Natural Resources Project Valuation, Thomas J. Straka, Steven H. Bullard Jan 1994

Forval A Software Package For Forestry And Natural Resources Project Valuation, Thomas J. Straka, Steven H. Bullard

Faculty Publications

FORV(AFLO ResVt ALuationis) an interactive, user-friendly computeprr ogramfo r discountedc ash flow analysis of forestry andn atural resource investments.M anyfo rest economics applicationsa re includeda nde mphasiiss on the nonindustrial privatef orest sector; howeveri,n dustrya ndp ublics ector applications are easily performewdi th the programC. alculations includen et presentv alue, equivalenta nnuali ncome,b enefit/ cost ratio, internal rate of return, future value, sinking funds, installmentp aymentsa, ndl and expectationv alue. Thep rogram also allows the user to accountf or amortizationo f reforestation costs andd epletiona llowancesI. t includess elf-contained instructionsa ndw ill generatet he details of key calculations. FORVsAhLou ldp …

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Basic Concepts In Computer Analysis Of Forestry Investments, Steven H. Bullard, Thomas J. Straka Jan 1994

Basic Concepts In Computer Analysis Of Forestry Investments, Steven H. Bullard, Thomas J. Straka

Faculty Publications

In the last 20 years alone, computer hardware and software developments have dramatically increased our ability to calculate financial criteria quickly and accurately. While these advances have dramatically increased our ability to calculate, they have not replaced the need to understand what is being calculated, or how the results should be interpreted and applied. Our objective in the present article is to provide background information for understandingthe "what" and "how" of computer applications for forestry investment analysis. We briefly discuss the most important financial criteria that are calculated by investment analysis computer programs; we also describe their recommended uses and …

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Morphometry Of Growth In Hatchling Striped Plateau Lizards (Iguanidae: Sceloporus Virgatus), Geoffrey R. Smith Jan 1994

Morphometry Of Growth In Hatchling Striped Plateau Lizards (Iguanidae: Sceloporus Virgatus), Geoffrey R. Smith

Faculty Publications

No abstract provided.

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