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Articles 45271 - 45300 of 52548

Full-Text Articles in Physical Sciences and Mathematics

Denial In The Decisive Decade: Towards Intervention And Common Action, Sandra Postel Jan 1992

Denial In The Decisive Decade: Towards Intervention And Common Action, Sandra Postel

Faculty Book Chapters

[abstract not provided]


National And Provincial Park Service Responses To Human-Induced Ecological Change In Ontario, Maria Theresia Kothbauer Jan 1992

National And Provincial Park Service Responses To Human-Induced Ecological Change In Ontario, Maria Theresia Kothbauer

Theses and Dissertations (Comprehensive)

This study examines the human-induced ecological changes occurring in Point Pelee and Pukaskwa National Parks and Rondeau and Lake Superior Provincial Parks as a result of external threats, as well as the methods used by park managers to prevent these changes. The primary objectives were to: examine the types of external threats and their implications to ecosystems in the selected parks; examine the responses of park managers to prevent changes in ecological integrity; determine whether or not the management techniques of park managers are rehabilitating and/or preventing ecological change induced by external threats: and make an initial comparison of national …


Managing Brome Grass In The Wheat:Lupin Rotation, Aik Hock Cheam, Gurget Gil, Christine Zaicou Jan 1992

Managing Brome Grass In The Wheat:Lupin Rotation, Aik Hock Cheam, Gurget Gil, Christine Zaicou

Journal of the Department of Agriculture, Western Australia, Series 4

Some farmers and scientists are questioning the sustainability of the cereal:lupin rotation in the Western Australian wheatbelt.

Being a 'tight' rotation, its continuation is constantly under threat by disease, especially lupin root rots caused by Pleiochaeta (the brown spot organism) and Rhizoctonia fungi. To control disease, some farmers have lengthened the rotation to three years, such as wheat:wheat:lupins or wheat:barley:lupins. The longer cereal phase also helps to stabilise soil against wind erosion. However, such rotations can lead to a rapid buildup of brome grass during the two consecutive years of cereals. The implications of these rotations on the severity of …


Taking The Emu To Market, Paul Frapple, Ruth Hagan Jan 1992

Taking The Emu To Market, Paul Frapple, Ruth Hagan

Journal of the Department of Agriculture, Western Australia, Series 4

Licensed, commercial emu farming in Western Australia is now five years old.

This year, 13,500 birds will be processed for their meat, skin and oil. Production has exceeded demand at prices which the industry considers fair because the industry is still developing marketd for these producys.

Without secure, long term markets, over-production will worsen as the turn-off in this State increases and emus become available from other Australian states and overseas.

The Department of Agriculture is assisting the industry to develop a viable industry.


The Role Of Earthworms In Western Australian Agriculture, Tom Mccredie, Lex Parker Jan 1992

The Role Of Earthworms In Western Australian Agriculture, Tom Mccredie, Lex Parker

Journal of the Department of Agriculture, Western Australia, Series 4

Earthworms have a reputation as soil builders and renovators, particularly among 'organic' farmers and gardeners. They improve soil fertility through increased aeration, aggregation, water infiltration and release of nutrients from organic matter. However, the benefits of earthworms in the wheatbelt have been doubted for many years because of their poor survival in cultivated soils.

Since cropping began in the Western Auslmlian whealbelt over 1OO years ago, the physical condition of many soils has deteriorated. The primary causes of soil degradation were the European cultivation practices used by farmers and the trampling effect of introduced animals. in particular, sheep.


Land Resources Study Of The Carnarvon Land Conservation District And Part Of Boolathana Station, Western Australia, M R. Wells, C D M Keating, J A. Bessell-Browne Jan 1992

Land Resources Study Of The Carnarvon Land Conservation District And Part Of Boolathana Station, Western Australia, M R. Wells, C D M Keating, J A. Bessell-Browne

Land resources series

A survey of the land resources of 36,343 ha covering the Carnarvon Land Conservation District and an adjoining portion of Boolathana station was conducted to assist future land use planning and management. This report describes the soil, landform and vegetation conditions of land units shown on an accompanying 1:50,000 scale map. These land units are components of land systems previously mapped at 1:250,000 scale for the Carnarvon Basin by Payne et al. (1987). As part of the study, further, more detailed land resource mapping and land capability assessments were conducted at specific locations. Land use planning and management considerations arising …


The Role Of Trees In Sustainable Agriculture : A National Conference : Reprints Of Western Australian Papers, P R. Scott Jan 1992

The Role Of Trees In Sustainable Agriculture : A National Conference : Reprints Of Western Australian Papers, P R. Scott

Resource management technical reports

  • The role of trees in land and stream salinity control in Western Australia (Conference paper: N.J. Schofield, M.A. Ban, D.T. Bell, W.J. Boddington, R.J. George, N.E. Pettit)
  • The role of trees in providing shelter and controlling erosion in the dry temperate and semi-arid southern agricultural areas of Western Australia (Conference paper: D. Bicknell)
  • Management of native woody vegetation on farms in Western Australia (Conference paper: J.P. Pigott)
  • Producing timber from trees - options for farmers in Western Australia (Conference paper: R. Moore)
  • Trees and shrubs as sources of fodder in Western Australia (Conference paper: E.C. Lefroy)
  • Minor forest products in …


Soils Of The Northam Advisory District. Volume 1. The Zone Of Ancient Drainage, Neil Clifton Lantzke Jan 1992

Soils Of The Northam Advisory District. Volume 1. The Zone Of Ancient Drainage, Neil Clifton Lantzke

Bulletins 4000 -

This manual describes the soils of the Department of Agriculture's Northam advisory district. Information is provided on the characteristics of each soil, its capability is discussed and yield estimates for the major land uses are given.

Designed for use by farmers and Department of Agriculture staff, the manual’s primary aims are to:

- Assist with the identification of the advisory district’s soils types

- Match land use with soil quality

- Improve farm productivity and efficiency

- Reduce the incidence of land degradation



Stubble : Friend And Foe, Department Of Agriculture And Food, Western Australia Jan 1992

Stubble : Friend And Foe, Department Of Agriculture And Food, Western Australia

Journal of the Department of Agriculture, Western Australia, Series 4

Several articles in this issue of the Journal of Agriculture discuss some of the important issues of stubble management. The articles are condensed from some of the papers presented at a stubble workshop at Geraldton in 1991.


The Pros & Cons Of Retaining Stubble, Department Of Agriculture And Food, Western Australia Jan 1992

The Pros & Cons Of Retaining Stubble, Department Of Agriculture And Food, Western Australia

Journal of the Department of Agriculture, Western Australia, Series 4

Few farmers in Western Australia today would question the desirability of retaining crop stubble. The problem usually is how to manage stubble so that it does not interfere with other parts of the farming system


Wider Spaced Rows For Lupins, Ron Jarvis Jan 1992

Wider Spaced Rows For Lupins, Ron Jarvis

Journal of the Department of Agriculture, Western Australia, Series 4

In this farm scale trial at Wongan Hills, a lined combine was used to seed lupins into rows spaced 380 mm apart in wheat stubble.


Results Of Stubble Research In Western Australia, Michael Perry, Ron Jarvis, Mel Mason, David Tennant Jan 1992

Results Of Stubble Research In Western Australia, Michael Perry, Ron Jarvis, Mel Mason, David Tennant

Journal of the Department of Agriculture, Western Australia, Series 4

Few farmers would question the desirability of retaining stubbles, both for control of erosion by wind and water, and to return organic matter to the soil. While the present debate is focused on the short term management of stubbles, longer term effects also need to be considered.

The Department of Agriculture has several long-running trials intended to measure long term effects.


Stubble Handling Begins At Harvest, Ed Blanchard Jan 1992

Stubble Handling Begins At Harvest, Ed Blanchard

Journal of the Department of Agriculture, Western Australia, Series 4

Long stubble left in the paddock after harvest causes major difficulties at seeding time. To demonstrate the benefits of having short stubble at seeding, the Trayning Land Conservation District Committee created four stubble treatments at harvest in 1988 and sowed into these stubble treatments in 1989.


Cost Effective Stubble Retention Practices, Andrew Green, Ed Blanchard Jan 1992

Cost Effective Stubble Retention Practices, Andrew Green, Ed Blanchard

Journal of the Department of Agriculture, Western Australia, Series 4

To increase the rate of adoption of stubble retention farming systems the Grains Research and Development Corporation is funding a three-year project with the Farm Machinery Unit to develop low cost, stubble handling systems from harvest to seeding


Red Kangaroos Can Set Back Range Regeneration, Andrew Mclaughlin Jan 1992

Red Kangaroos Can Set Back Range Regeneration, Andrew Mclaughlin

Journal of the Department of Agriculture, Western Australia, Series 4

After years of severe drought, stocking rates in Western Australia s arid rangelands have been kept low since the 1970s to allow native pastures to regenerate. As well, extensive re-seeding programs have started and sheep and cattle grazing on these areas has been restricted or eliminated. However, pasture regeneration in the rangelands can only succeed when grazing by all animals - sheep, cattle, kangaroos, goo.ts, camels, brumbies and donkeys - is controlled Many more red kangaroos roam throughout Western Australia's pastoral areas today than 20 years ago. The installation of windmills and troughs to water domestic livestock has allowed kangaroo …


How To Reduce Spending On Land Conservation, Tim Negus Jan 1992

How To Reduce Spending On Land Conservation, Tim Negus

Journal of the Department of Agriculture, Western Australia, Series 4

Heavy spending on capital works for land conseroation is usually out of the question in the present financial climate, but the recession does not mean that landcare must be abandoned. There are many aspects of landcare that involve little or no extra cost. Soil conseroationist Tim Negus discusses them in this article.


How Arsenic Residues Get In Wool, Tony Martin, Robin Jacob, Marion Davies, Peter Rutherford Jan 1992

How Arsenic Residues Get In Wool, Tony Martin, Robin Jacob, Marion Davies, Peter Rutherford

Journal of the Department of Agriculture, Western Australia, Series 4

Wool can become contaminated with arsenic in various ways, and several different sources may each contribute to any individual arsenic residue problem.

• dipping sheep in an arsenical dip ( now illegal),

• dipping sheep in a non-arsenical dip in a contaminated dipping facility

• penning sheep on soil with high levels of arsenic before shearing.

Other possible sources include running sheep on land contaminated by gold mine tailings or exploration sites, and allowing sheep access to sites on the farm where arsenical compounds have been dumped, for example, rubbish dumps or sites where dip/sump sludge has been dumped.

Farmers …


Biomass Conversion Of Solid-Waste (Newsprint) Into A Clean Fuel (Ethanol) By Enzymic Hydrolysis And Fermentation, Nimesh V. Gandhi Dec 1991

Biomass Conversion Of Solid-Waste (Newsprint) Into A Clean Fuel (Ethanol) By Enzymic Hydrolysis And Fermentation, Nimesh V. Gandhi

Theses

A feasibility study has been performed with two bioprocesses for conversion of newsprint waste to an environmentally safe fuel (ethyl alcohol) and carbon dioxide.

The following areas were investigated to accomplish this task: one hour pretreatment of newsprint by attrition, saccharification of paper slurry to glucose by cellulase and cellobiase, effects of pH, temperature and concentration of enzymes on conversion of paper to sugar, fermentation of glucose to ethanol and carbon dioxide by immobilized yeast, and simultaneous saccharification and fermentation of paper to ethanol and carbon dioxide using enzymes and immobilized yeast.

Results indicate that the enzymic hydrolysis of newsprint …


Measurement Of The Removal Of Selected Vocs From A Municipal Treatment Plant, Hong Yu Dec 1991

Measurement Of The Removal Of Selected Vocs From A Municipal Treatment Plant, Hong Yu

Theses

Industrial wastewater contains a variety of volatile chemical constituents. The large majority of the volatiles are organics. Many of these volatile or¬ganic compounds (VOCs) end up in the effluent to wastewater treatment plants. It is necessary to estimate the emission of the VOCs from sewerage plants in order to study the fate of these volatile organic compounds.

This study focuses on the estimation and comparison of the emission of 28 volatile organic compounds from the water and air in four operation units of Linden Roselle Sewerage Authority (LRSA) wastewater treatment plant. The removal rates of these target compounds have been …


The Effects Of Oxygen Tension On Nitrate Reduction By Pseudomonas Isolate, Hao-Jan Hsing Dec 1991

The Effects Of Oxygen Tension On Nitrate Reduction By Pseudomonas Isolate, Hao-Jan Hsing

Theses

It is a generally accepted concept that nitrate reduction only occurs under anaerobic conditions. Oxygen inhibits denitrification. However many studies of nitrate reduction under low oxygen tension have shown what has been called aerobic denitrification. This project examines the process of aerobic denitrification.

Oxgyen affects cell growth and the amount of nitrate utilized. When oxygen is absent, the cell growth rate is lower and nitrate utlization is higher then when oxygen is present.

Nitrate is reduced to nirite under anaerobic conditions. Nitrite accumulation did not continue increase. But increased then decreased producing a "Z" shaped graph when plotted.


Bird Response To Monofilament Lines At Backyard Feeders, Kimberly K. Kessler Dec 1991

Bird Response To Monofilament Lines At Backyard Feeders, Kimberly K. Kessler

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Biology And Ecology Of Dioryctria Ponderosae Dyar And Dioryctria Tumicolella Mutuura, Munroe And Ross, Mark A. Brohman Dec 1991

Biology And Ecology Of Dioryctria Ponderosae Dyar And Dioryctria Tumicolella Mutuura, Munroe And Ross, Mark A. Brohman

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Ecological Aspects Of Burrowing Owl Nesting Strategies In The Nebraska Panhandle, Martha J. Desmond Dec 1991

Ecological Aspects Of Burrowing Owl Nesting Strategies In The Nebraska Panhandle, Martha J. Desmond

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Water Current, Volume 23, December 1991 Dec 1991

Water Current, Volume 23, December 1991

Water Current Newsletter

Massengale Presents Challenges at University Water Policy Forum
Governor Nelson Discusses Environmental Concerns at Nebraska Groundwater Foundation Luncheon
Report from the Director: Education and Research High Priorities
Surveys of Water-Related College-Education and Employment in Nebraska
California's Water Problems Explained at NGF Symposium
Cancer and Water Quality, Topic of Seminar
Wetlands Topic for 1992 Nebraska Water Conference
Environmental Cleanup Liabilities Farmers Should Consider
Eight States Evaluated in Groundwater Quality Research
Hungarian Students, Researchers to Collaborate in Environmental Degradation Studies


Environmental Radiocesium In Subarctic And Arctic Alaska Following Chernobyl, M. Baskaran, J. J. Kelley, A. S. Naidu, D. F. Holleman Dec 1991

Environmental Radiocesium In Subarctic And Arctic Alaska Following Chernobyl, M. Baskaran, J. J. Kelley, A. S. Naidu, D. F. Holleman

Environmental Science and Geology Faculty Research Publications

Radiocesium (¹³⁴ Cs and ¹³⁷ Cs) concentrations were measured in soil, plant and wildlife samples from subarctic to arctic Alaska. Concentrations of ¹³⁷ Cs ranged from below detectable or low levels in whale and fish samples to as high as 242 Bq/kg in lichen. For all potential human food items, the radiocesium concentrations measured in this study were below accepted permissible levels for human consumption. Chernobyl-derived radiocesium concentrations ranged from below detectable or low levels in all arctic samples (soil, sediment, lichen, whale, fish and caribou) to 32 Bq/kg in subarctic moss. Therefore the distribution and subsequent deposition of Chernobyl-derived …


Hepatic Microsomal N-Hydroxylation Of Aniline And 4-Chloroaniline By Rainbow Trout (Onchorhyncus Mykiss), Steven P. Bradbury, J. M. Dady, A. D. Hoffman, M. M. Voit, D. L. Olson Dec 1991

Hepatic Microsomal N-Hydroxylation Of Aniline And 4-Chloroaniline By Rainbow Trout (Onchorhyncus Mykiss), Steven P. Bradbury, J. M. Dady, A. D. Hoffman, M. M. Voit, D. L. Olson

Steven P. Bradbury

N-Hydroxylation of aniline and 4-chloroaniline was quantified in rainbow trout microsomal preparations using h.p.l.c.-liquid scintillation methods. Radioactive phenylhydroxylamine and 4-chlorophenylhydroxylamine metabolites were identified by co-elution with non-labelled standards. The method provided resolution of metabolite standards, and quantification of both N-hydroxylated metabolites was achieved without derivatization. The maximum velocities at 25 degrees C were 33.8 +/- 1.40 and 22.0 +/- 0.98 pmol/min per mg for aniline and 4-chloroaniline N-hydroxylation, respectively. The Km values were 1.0 +/- 0.11 and 0.8 +/- 0.11 mM for aniline and 4-chloroaniline N-hydroxylation, respectively. These activities were not induced by treatment of the trout with Aroclor 1254 …


The Probe, Issue 117 - December 1991 Dec 1991

The Probe, Issue 117 - December 1991

The Probe: Newsletter of the National Animal Damage Control Association

THE PROBE
National Animal Damage Control Association
DECEMBER 1991
Evaluating Performance of the Soft-Catch® Coyote Trap
Calendar of Upcoming Events
President Bush Has Unique Style Of Animal Damage Control
Soft-Catch® Traps...
Animal Damage Control in the News:
It’s the “Gull War” at Kennedy International
Cyanide Baits May Be Allowed on BLM Land
Pocket Gopher Control Evaluation at Rogue River National Forest
“USA” Today Lists Predator Protection Tips
International Resolution Supports Regulated Trapping
Over Forty NADCA Members Attend 5th Eastern Wildlife Damage Control Conference
USDA Is Helping to Limit Rabies Outbreak In Texas
Wildlife Veterinarians Adopt Position Statement on Oral Rabies …


Remote Estimation Of The Diffuse Attenuation Coefficient In A Moderately Turbid Estuary, Richard P. Stumpf, Jonathan Pennock Dec 1991

Remote Estimation Of The Diffuse Attenuation Coefficient In A Moderately Turbid Estuary, Richard P. Stumpf, Jonathan Pennock

School of Marine Science and Ocean Engineering

Abstract

Solutions of the radiative transfer equation are used to derive relationships of water reflectance to the diffuse attenuation coefficient (K) in moderately turbid water (K > 0.5 m−1). Data sets collected from the NOAA AVHRR and in situ observations from five different dates confirm the appropriateness of these relationships, in particular the logistic equation. Values of K calculated from the reflectance data agree to within 60% of the observed values, although the reflectance derived using a more comprehensive aerosol correction is sensitive to chlorophyll concentrations greater than 50 μg L−1. Agreement between in situ and remote …


The Prairie Naturalist Volume 23, No. 4. December 1991 Dec 1991

The Prairie Naturalist Volume 23, No. 4. December 1991

The Prairie Naturalist

Paul B. Kannowski, Editor

Nikki R. Seabloom, Assistant Editor

Douglas H. Johnson, Book Review Editor

CONTENTS

KENTUCKY BLUEGRASS RESPONSE TO BURNING: INTERACTIONS BETWEEN FIRE AND SOIL MOISTURE ▪ G. W. Blankespoor and B. S. Bich

FORAGE PRODUCTION AND USE ON BIGHORN SHEEP WINTER RANGE

FOLLOWING SPRING BURNING IN GRASSLAND AND PONDEROSA PINE HABITATS ▪ T. G. Easterly and K. J. Jenkins

SHORT-TERM MORTALITY OF SMALLMOUTH BASS CAUGHT DURING A LIVE-RELEASE TOURNAMENT AT LAKE OAHE, SOUTH DAKOTA ▪ J. J. Jackson and D. W. Willis

CRAYFISH IN SAND LAKE NATIONAL WILDLIFE REFUGE ▪ C. D. Dieter

PIPING PLOVERS NEST ON DRY …


Preliminary Epidemiological Interpretation Of The Intrinsic And Extrinsic Factors Contributing To The Coverage And Participation Rates Of The Vaccination Program In Arssi, Ethiopia, Muchie Kidanu Dec 1991

Preliminary Epidemiological Interpretation Of The Intrinsic And Extrinsic Factors Contributing To The Coverage And Participation Rates Of The Vaccination Program In Arssi, Ethiopia, Muchie Kidanu

Electronic Theses and Dissertations

Many immunization programs in developing countries arr now undergoing a period of rapid utilization. Innovative strategies, such as immunization holidays, are being tried. Political commitment and enthusiasm are high. There is a strong desire by health professionals to protect the lives of many children from the untimely death and/or disability resulting from infectious diseases preventable by vaccination.

Evaluation of an immunization program can benefit other elements of the health system, particularly those that are not amenable to objective evaluation as immunization. In this case, immunization can serve as an indicator of the overall performance of the health system. The problems …