Digital Commons Network^™

Hydraulic Core Extraction: Cutting Device For Soil–Root Studies, T. S. Kornecki, S. A. Prior, G. B. Runion, H. H. Rogers, D. C. Erbach

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A critical objective of belowground research is to collect and process representative soil samples. Mechanical devices have been developed to quickly take soil cores in the field; however, techniques to rapidly process large-diameter soil cores are lacking. Our objective was to design and construct a soil extraction–cutting system that could effectively reduce processing time. Soil cores were extracted from large diameter steel core tubes using a custom hydraulic cylinder device that vertically pushes the soil core to a desired depth increment before cutting in a horizontal direction with another hydraulically driven device. As many as eight large cores per hour …

Growth And Feed Efficiency Of Juvenile Channel Catfish Reared At Different Water Temperatures And Fed Diets Containing Various Levels Of Fish Meal, Menghe H. Li, Edwin H. Robinson, Brian C. Peterson, Terry D. Bates

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Channel catfish Ictalurus punctatus do not feed well at low temperatures. It is generally thought that a diet containing fish meal enhances feed palatability at low temperatures since fish meal is highly palatable to fish. There is a lack of information on the effects of fish meal levels on the growth performance of channel catfish reared at low temperatures. Therefore, a study was conducted in a recirculating system to examine the effects of fish meal levels on the feed consumption, weight gain, and feed efficiency of juvenile channel catfish reared at various temperatures. Fish with an initial weight of 9.6 …

Nationally Coordinated Evaluation Of Soil Nitrogen Mineralization Rate Using A Standardized Aerobic Incubation Protocol, T. S. Griffin, C. W. Honeycutt, S. L. Albrecht, K. R. Sistani, H. A. Torbert, B. J. Wienhold, B. L. Woodbury, R. K. Hubbard, J. M. Powell

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Aerobic incubation methods have been widely used to assess soil nitrogen (N) mineralization, but standardized protocols are lacking. A single silt loam soil (Catlin silt loam; fine-silty, mixed, superactive, mesic, Oxyaquic Arguidoll) was subjected to aerobic incubation at six USDA-ARS locations using a standardized protocol. Incubations were conducted at multiple temperatures, which were combined based on degree days (DD). Soil water was maintained at 60% waterfilled pore space (WFPS; constant) or allowed to fluctuate between 60 and 30% WFPS (cycle). Soil subsamples were removed periodically and extracted in 2 M potassium chloride (KCl); nitrate (NO₃) and ammonium (NH …

Areawide Suppression Of Fire Ants, M. D. Aubuchon, R. K. Vander Meer

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The imported fire ants, Solenopsis invicta and S. richteri, were inadvertently introduced into the USA in the early 1900s and currently inhabit over 129 million ha in Puerto Rico and 12 southern states, from Texas to Virginia (Callcott and Collins, 1996; USDA-APHIS map). Imported fire ants have also become established in isolated sites in California, Arizona, New Mexico and Maryland. Strict quarantine procedures have limited the spread of this pest (Lockley and Collins, 1990), but eventually populations will expand westward in increasing numbers in New Mexico, Arizona and California. They will also move upward along the Pacific coast, southward …

The Hawaii Fruit Fly Areawide Pest Management Programme, Roger I. Vargas, Ronald F. L. Mau, Eric B. Jang, Robert M. Faust, Lyle Wong

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Fruit flies (Diptera: Tephritidae) are among the most economically important pests attacking soft fruits worldwide (White and Elson-Harris, 1992). Four invasive species Mediterranean fruit fly or medfly (Ceratitis capitata), melon fly (Bactrocera cucurbitae), oriental fruit fly (Bactrocera dorsalis) and the so-called Malaysian fruit fly or solanaceous fruit fly (Bactrocera latifrons) - have been devastating to Hawaiian agriculture for over 100 years by infesting more than 400 different host plants. These fruit flies:

• Jeopardize development of a diversified tropical fruit and vegetable industry.

• Require that commercial fruits undergo quarantine treatment prior …

Improving Grassland Profitability In The Mid-Continental Usa By Breeding For Improved Forage Digestibility: Lessons Learned And Applications To South American Grasslands Lncrementos Na Lucratividade De Pastagens No Centro Continental Dos Estados Unidos Da America Do Norte Pelo Melhoramento Para Melhor Digestibilidade De Forragens: L I~6esap Rendidas E Implicaq6es Para Pastagens Na America Do Sul, Kenneth P. Vogel, Cesar Heraclides Behling Miranda

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In the early 1970's research was initiated by the cooperative USDA-ARS and University of Nebraska grass breeding program to develop perennial grasses adapted to the mid-continental USA with improved forage quality. The initial breeding and animal evaluation work focused on switchgrass (Panicurn virgatum) but has since expanded to several other warmand cool-season perennial grasses. The in vitro dry matter digestibility (IVDMD) test was selected as the measure of forage quality that was used in the breeding work because of its previous successful application on improving bermudagrass (Cynodon dactylon). In all of the grass species that we …

Cell-Wall Composition And Accessibility To Hydrolytic Enzymes Is Differentially Altered In Divergently Bred Switchgrass (Panicum Virgatum L.) Genotypes, Gautam Sarath, Danny E. Akin, Robert B. Mitchell, Kenneth P. Vogel

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The aims of this study were to understand the genotypic variability in cell-wall composition and cell-wall accessibility to enzymes in select switchgrass plants obtained from two different populations derived from a base population of octaploid cultivars. Population C+3 was developed by three breeding generations for high digestibility and population C−1 developed by one generation of breeding for low digestibility. Aboveground biomass from 12 selected genotypes, three each with high or low digestibility within each population, was analyzed for their cell-wall aromatics and polysaccharides. The ratio of p-coumaric acid/ferulic acid was greater (P≤0.05) for the high-lignin C−1 population over the …

Short Communication- An Update On The Diversity Of Wolbachia In Spalangia Spp. (Hymenoptera: Pteromalidae), K.D. Floate, P.C. Coghlin, D. B. Taylor

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Results from 13 additional host populations improves resolution on the diversity of Wolbachia bacteria in Spalangia spp. (Hymenoptera: Pteromalidae). These bacteria are of interest because they can profoundly affect their host’s reproduction. Manipulating Wolbachia infections may provide a method to improve the efficacy of biocontrol agents including Spalangia spp.

Parasitoid wasps (Pteromalidae: Hymenoptera) are of interest as biocontrol agents for pest flies (Diptera: Muscidae) of livestock confinements; e.g. dairies, cattle feedlots, poultry houses, swine barns. Many of these wasps are infected with Wolbachia bacteria that can profoundly affect their host’s reproduction. Wolbachia induce parthenogenesis in Muscidifurax uniraptor Kogan & Legner …

Comparison Of Two Soil Quality Indexes To Evaluate Cropping Systems In Northern Colorado, T.M. Zobeck, A.D. Halvorson, Brian J. Wienhold, V. Acosta-Martinez, D. L. Karlen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Various soil management or quality assessment tools have been proposed to evaluate the effects of land management practices on soil, air, and water resources. Two of them are the Soil Management Assessment Framework and the Soil Conditioning Index (SCI). This study was conducted to test the hypothesis that the Soil Quality Index (SQI) estimated by the Soil Management Assessment Framework can detect more minute changes in soil management than SCI and to test SCI response to other soil quality (SQ) indicators. These SQ indexes were tested on irrigated cropping systems near Fort Collins, Colorado, that included no-till and conventionally-tilled corn …

Recent Advances In Soil Quality Assessment In The United States, Brian J. Wienhold, S.S. Andrews, H. Kuykendall, D. L. Karlen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Soil quality is a concept that is useful as an educational and assessment tool. A number of assessment tools have been developed including: the Soil Conditioning Index (SCI), the Soil Management Assessment Framework (SMAF), the AgroEcosystem Performance Assessment Tool (AEPAT), and the new Cornell “Soil Health Assessment”. The SMAF and AEPAT were developed as malleable tools for assessing soil response to management. The Cornell Assessment builds on the SMAF approach to score laboratory tests in terms of soil function. This paper updates efforts to improve availability and utility, implementation, and future research goals associated with the SMAF. Additional scoring curves …

Winds Of Change: A Century Of Agroclimate Research, Jean L. Steiner, Jerry L. Hatfield

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Climate has been of primary concern from the beginning of agricultural research. Early in the 20th century, climatology and agronomy evolved separately, focusing primarily on production agriculture and crop adaptation. Concepts developed include thermal units and water use efficiency. The integrated discipline of agroclimatology developed in the mid-20th century. As theoretical understanding evolved, numerous papers related to agroclimatology were named Citation Classics. Spectral properties of plants and soils were identified that underpin today’s remote sensing technologies. Commercialization of instrumentation enhanced our ability to efficiently collect data using standardized methods. Private and public-sector partnerships advanced research capacity. Later in the 20th …

An Embarrassment Of Riches: The Enzymology Of Rna Modification, Dirk Iwata-Reuyl

Chemistry Faculty Publications and Presentations

The maturation of transfer RNA (tRNA) involves extensive chemical modification of the constituent nucleosides and results in the introduction of significant chemical diversity to tRNA. Many of the pathways to these modified nucleosides are characterized by chemically complex transformations, some of which are unprecedented in other areas of biology. To illustrate the scope of the field, recent progress in understanding the enzymology leading to the formation of two distinct classes of modified nucleosides, the thiouridines and queuosine, a 7-deazaguanosine, is reviewed. In particular, recent data validating the involvement of several proposed intermediates in the formation of thiouridines are discussed, including …

Volatile Compounds From The Integument Of White Leghorn Chickens (Gallus Gallus Domesticus L.): Candidate Attractants Of Ornithophilic Mosquito Species, Ulrich R. Bernier, Sandra A. Allan, Brian Quinn, Daniel Kline, Donald Barnard, Gary Clark

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Candidate kairomones of ornithophilic mosquito species are reported from GC/MS analysis of compounds from the skin on the back, the feet, and feathers from the back of White Leghorn chickens (Gallus gallus domesticus). Hexane and ether extracts of chicken feathers differ significantly in attractiveness of Culex spp. mosquitoes. The active (hexane) extracts contained an abundance of alcohols, ketones, and diones. The inactive (ether) extracts contained aldehydes, which also were in the hexane extracts. Analysis of hexane extracts from chicken feet, skin, and feathers demonstrated the qualitative similarity in the compounds collected with subtle differences observed in the quantitative …

Discovery Of Diurnal Resting Sites Of Phlebotomine Sand Flies In A Village In Southern Egypt, Jerome Hogsette, Hanafi A. Hanafi, Ulrich R. Bernier, Daniel L. Kline, Emad Y. Fawaz, Barry D. Furman, David F. Hoel

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In an attempt to find diurnal resting sites of adult phlebotomine sand flies, potential phlebotomine adult habitats were aspirated in the village of Bahrif in Aswan, Egypt. During this survey, sand flies were aspirated from low (30–45 cm high) irregular piles of mud bricks found under high date palm canopies between the village and the Nile River. There were 5 ♂♂and 7 ♀♀ of Phlebotomus papatasi and 3♂♂ of Sergentomyia schwetzi. Six of the 7 aspirated females were engorged with blood. A total of 78 sand flies was captured on 3 glue boards placed overnight on the ground next …

Unsymmetric Aryl–Alkyl Disulfide Growth Inhibitors Of Methicillin-Resistant Staphylococcus Aureus And Bacillus Anthracis, Edward Turos, Kevin D. Revell, Praveen Ramaraju, Danielle A. Gergeres, Kerriann Greenhalgh, Ashley Young, Nalini Sathyanarayan, Sonja Dickey, Daniel Lim, Mamoun M. Alhamadsheh, Kevin A. Reynolds

Chemistry Faculty Publications and Presentations

This study describes the antibacterial properties of synthetically-produced mixed aryl alkyl disulfide compounds as a means to control the growth of Staphylococcus aureus and Bacillus anthracis. Some of these compounds exerted strong in vitro bioactivity. Our results indicate that among the twelve different aryl substituents examined, nitrophenyl derivatives provide the strongest antibiotic activities. This may be the result of electronic activation of the arylthio moiety as a leaving group for nucleophilic attack on the disulfide bond. Small alkyl residues on the other sulfur provide the best activity as well, which for different bacteria appears to be somewhat dependent on …

Fibroblast Growth Factor -19: A Novel Factor That Inhibits Hepatic Fatty Acid Synthesis., Sushant Bhatnagar

Graduate Theses, Dissertations, and Problem Reports (ETD)

Previous studies have shown that administration of fibroblast growth factor-19 (FGF-19) reverses diabetes, hepatic steatosis, hyperlipidemia, and adipose accretion in animal models of obesity. To investigate the mechanism for this effect, we determined whether FGF-19 modulated hepatic fatty acid synthesis, a key process controlling glucose tolerance and triacylglycerol accumulation in liver, blood, and adipose tissue. Incubating primary hepatocyte cultures with recombinant FGF-19 suppressed the ability of insulin to stimulate fatty acid synthesis. This effect was associated with a reduction in the expression of lipogenic enzymes. FGF-19 also suppressed the insulin-induced expression of sterol regulatory element-binding protein-1c (SREBP-1c), a key transcriptional …

Construction, Installation, And Performance Of Two Repacked Weighing Lysimeters, José O. Payero, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Weighing lysimeters are the standard method for directly measuring evapotranspiration (ET). This paper discusses the construction, installation, and performance of two (1.52 m × 1.52 m × 2.13-m deep) repacked weighing lysimeters for measuring ET of corn and soybean in West Central Nebraska. The cost of constructing and installing each lysimeter was approximately US $12,500, which could vary depending on the availability and cost of equipment and labor. The resolution of the lysimeters was 0.0001 mV V^-1, which was limited by the data processing and storage resolution of the datalogger. This resolution was equivalent to 0.064 and 0.078 …

Variability Analyses Of Alfalfa-Reference To Grass-Reference Evapotranspiration Ratios In Growing And Dormant Seasons, Suat Irmak, Ayse Kilic, T. A. Howell, Derrel Martin, J. O. Payero, K. S. Copeland

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Alfalfa-reference evapotranspiration (ET_r) values sometimes need to be converted to grass-reference ET (ET_o), or vice versa, to enable crop coefficients developed for one reference surface to be used with the other. However, guidelines to make these conversions are lacking. The objectives of this study were to: (1) develop ET_r to ET_o ratios (K_r values) for different climatic regions for the growing season and nongrowing (dormant) seasons; and (2) determine the seasonal behavior of K_r values between the locations and in the same location for different seasons. Monthly average K_r values …

Surface Polyethylene Glycol Enhances Substrate-Mediated Gene Delivery By Nonspecifically Immobilized Complexes, Angela K. Pannier, Julie A. Wieland, Lonnie D Shea

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Substrate-mediated gene delivery describes the immobilization of gene therapy vectors to a biomaterial, which enhances gene transfer by exposing adhered cells to elevated DNA concentrations within the local microenvironment. Surface chemistry has been shown to affect transfection by nonspecifically immobilized complexes using self-assembled monolayers (SAMs) of alkanethiols on gold. In this report, SAMs were again used to provide a controlled surface to investigate whether the presence of oligo(ethylene glycol) (EG) groups in a SAM could affect complex morphology and enhance transfection. EG groups were included at percentages that did not affect cell adhesion. Nonspecific complex immobilization to SAMs containing combinations …

Modeling Canopy Photosynthesis Of A Scrub-Oak Ecosystem Under Elevated Co2, Lori Jones

Electronic Theses and Dissertations

Rising atmospheric CO2 and the need to understand potential impacts on terrestrial ecosystems has become increasingly recognized. Models can play a beneficial part in this research to enhance understanding of ecosystem responses to changing conditions like elevated CO2. In this study, data from a long term elevated CO2 experiment in a native forested ecosystem in east central Florida were employed to assess the utility of a multi-layer canopy photosynthesis model as a tool to better understand the responses to elevated CO2 in this ecosystem. Model results compared satisfactorily with the canopy gas exchange measurements in this ecosystem for the period …

Enteric Bacteria Of Field-Collected Colorado Potato Beetle Larvae Inhibit Growth Of The Entomopathogens Photorhabdus Temperata And Beauveria Bassiana, Michael B. Blackburn, Dawn E. Gundersen-Rindal, Donald C. Weber, Phyllis A. W. Martin, Robert R. Farrar Jr.

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The nematode Heterorhabditis marelatus fails to reproduce in the Colorado potato beetle, Leptinotarsa decemlineata, possibly due to interference from the enteric bacteria of the beetle. Specifically, the enteric bacteria inhibit the growth of Photorhabdus temperata, the enteric symbiont of the nematode, in vitro. However, previous work was based on a laboratory culture of L. decemlineata, and we wished to determine if similar bacteria were present in the field. Therefore, we cultured the enteric bacteria of fourth-instar larvae collected from the field at two locations in Maryland and Virginia. Representatives of the genera Pantoea, Enterobacter, Pseudomonas …

The Genetic Diversity, Relationships, And Potential For Biological Control Of The Lobate Lac Scale, Paratachardina Pseudolobata Kondo & Gullan (Hemiptera: Coccoidea: Kerriidae), S. Schroer, R. W. Pemberton, L. G. Cook, T. Kondo, P. J. Gullan

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The lobate lac scale Paratachardina pseudolobata Kondo & Gullan (Kerriidae) is a polyphagous pest of woody plants in Florida (U.S.A.) the Bahamas, Christmas Island (Australia) and it has been reported from Cuba. Its recent appearance as a pest in these places indicates that this scale is introduced; however, its native range is unknown. Until 2006, this pest species was identified mistakenly as Paratachardina lobata (Chamberlin) [now P. silvestri (Mahdihassan)], which is native to India and Sri Lanka. Quarantine laboratory acceptance trials with Indian P. silvestri parasitoids indicated a strong immune response from P. pseudolobata. Gregarious development of encyrtid wasps …

A Core Set Of Microsatellite Markers For Western Corn Rootworm (Coleoptera: Chrysomelidae) Population Genetics Studies, Kyung Seok Kim, Uwe Stolz, Nicholas J. Miller, Miller R. Waits, Thomas Guillermaud, Douglas V. Sumerford, Thomas W. Sappington

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Interest in the ecological and population genetics of the western corn rootworm, Diabrotica virgifera virgifera LeConte, has grown rapidly in the last few years in North America and Europe. This interest is a result of a number of converging issues related to the increasing difficulty in managing this pest and the need to characterize and understand gene ßow in the context of insect resistance management. One of the key components needed for successful population genetics studies is the availability of suitable molecular markers. Using a standard group of microsatellite markers enables researchers from different laboratories to directly compare and share …

Entomopathogenic Fungal Endophytes, Fernando E. Vega, Francisco Posada, M. Catherine Aime, Monica Pava-Ripoll, Francisco Infante, Stephen A. Rehner

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Fungal endophytes are quite common in nature and some of them have been shown to have adverse effects against insects, nematodes, and plant pathogens.
Our research program is aimed at using fungal endophytes-mediated plant defense as a novel biological control mechanism against the coffee berry borer, the most devastating pest of coffee throughout the world. A survey of fungal endophytes in coffee plants from Hawaii, Colombia, Mexico, and Puerto Rico has revealed the presence of various genera of fungal entomopathogens, including Acremonium, Beauveria, Cladosporium, Clonostachys, and Paecilomyces. Two of these, B. bassiana and Clonostachys rosea …

The Role Of Sex, Gender Role, And Extraversion-Introversion In Explaining The Experience, Expression And Control Of Anger, James Oliver

Theses : Honours

Anger is a frequently experienced emotion that has been shown to influence perceptions, beliefs, ideas, reasoning, and ultimately choices and actions. It has the potential to become a serious problem if it reaches dysfunctional levels. This study examines the role of biological sex, gender role, and extraversion-introversion in the expression, experience and control of anger. A sample of 110 persons drawn from the Australian community were administered the Staxi-2, EPQ-R and the BSRI. Results showed that extraversion-introversion accounted for most variance associated with anger expression, while gender role accounted for most variance associated with anger control. Biological sex was not …

Self-Efficacy, Sense Of Belonging And Social Support As Predictors Of Resilience In Adolescents, Anna Nowicki

Theses : Honours

Adolescence has been described as a period of many physical, cognitive and psychosocial changes. During such a tumultuous time some adolescents cope better than others with life stressors, and these individuals can be considered resilient. The degree to which a person is resilient can be influenced and determined by protective factors, including social support, sense of belonging and self-efficacy. Positive social support has been identified as a buffer that protects individuals from the negative effects of stressful life situations. A strong sense of belonging has positively reflected adolescents' motivation, participation and ability to relate to their environment. Self-efficacy has also …

New Insights Into The Controls And Mechanisms Of Plankton Productivity Along The Us West Coast, Raphael M. Kudela, Neil S. Banas, John A. Barth, Elizabeth R. Frame, David A. Jay, John L. Largier, Evelyn J. Lessard, Tawnya D. Peterson, Andrea J. Vander Woude

Civil and Environmental Engineering Faculty Publications and Presentations

During the lifetime of the National Science Foundation's Coastal Ocean Processes program, four experiments were conducted on the US West Coast in the northern California Current System. Although each project had a unique scientific focus, all four addressed the mechanisms causing eastern boundary current systems in general, and the California Current System in particular, to be biologically rich, from phytoplankton to apex predators. Taken together, findings from these projects provide new insights into the canonical view that upwelling systems are simple wind-driven "conveyor belts," bringing cold, nutrient-rich waters to the well-lit surface ocean where biological organisms flourish. We highlight new …

Daily Forecasts Of Columbia River Plume Circulation: A Tale Of Spring/Summer Cruises, Yinglong J. Zhang, Antonio M. Baptista, Barbara M. Hickey, Byron C. Crump, David A. Jay, Michael Wilkin, Charles Seaton

Civil and Environmental Engineering Faculty Publications and Presentations

Semi-operational daily forecasts of circulation from an observatory for the Columbia River estuary-plume-shelf system routinely support oceanographic cruises, by providing 24h-ahead estimates of plume location and structure for planning purposes and for near real-time interpretation of observations. This paper analyzes forecast skill during spring/summer cruises in 2004-2007. Assessment addresses both qualitative descriptions of major plume trends and features and quantitative representation of data from (primarily) vessel-based flow-through, cast and towed systems. Forecasts emerge as robust predictors of plume location and variability, with skill that has grown over time, at least in part due to improvements in model algorithms. When the …

Seasonal Variability And Estuary-Shelf Interactions In Circulation Dynamics Of A River-Dominated Estuary, Arun Chawla, David A. Jay, Antonio M. Baptista, Michael Wilkin, Charles Seaton

Civil and Environmental Engineering Faculty Publications and Presentations

The long-term response of circulation processes to external forcing has been quantified for the Columbia River estuary using in situ data from an existing coastal observatory. Circulation patterns were determined from four Acoustic Doppler Profilers (ADP) and several conductivity-temperature sensors placed in the two main channels. Because of the very strong river discharge, baroclinic processes play a crucial role in the circulation dynamics, and the interaction of the tidal and subtidal baroclinic pressure gradients plays a major role in structuring the velocity field. The input of river flow and the resulting low-frequency flow dynamics in the two channels are quite …

Influence De La Charge De Travail Sur Les Indicateurs Biologiques D'Exposition De Cinq Solvants, Robert Tardif, Ginette Charest-Tardif, Ginette Truchon, Martin Brochu

Rapports de recherche scientifique

Plusieurs facteurs qui sont susceptibles d’exercer un impact majeur sur le comportement des contaminants dans l’organisme des individus exposés. À cet égard, la ventilation alvéolaire joue un rôle particulièrement important puisqu’elle est directement influencée par l’intensité de l’activité physique ou de la charge de travail. Or toute augmentation de cette charge de travail se traduit par une augmentation de la ventilation alvéolaire laquelle dépend de la fréquence respiratoire et du volume courant. Selon les produits en cause, ces modifications physiologiques peuvent avoir des répercussions importantes sur les quantités de contaminants absorbées et sur leur élimination, et par conséquent, sur leurs …