Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- University of Nebraska - Lincoln (10566)
- University of Kentucky (10462)
- Utah State University (2395)
- Old Dominion University (2269)
- TÜBİTAK (1962)
-
- University of South Florida (1623)
- Nova Southeastern University (1321)
- Portland State University (1316)
- Louisiana State University (1260)
- University of Arkansas, Fayetteville (1201)
- University of Nevada, Las Vegas (1099)
- University of Texas Rio Grande Valley (1057)
- Missouri University of Science and Technology (970)
- University of South Carolina (903)
- Department of Primary Industries and Regional Development, Western Australia (875)
- University of Northern Iowa (862)
- Brigham Young University (860)
- City University of New York (CUNY) (818)
- Wright State University (736)
- Virginia Commonwealth University (715)
- Clemson University (629)
- Chulalongkorn University (620)
- Western Kentucky University (608)
- Technological University Dublin (592)
- University of Texas at El Paso (586)
- Marquette University (585)
- South Dakota State University (566)
- University of Central Florida (555)
- Singapore Management University (553)
- University of New Mexico (551)
- Keyword
-
- Climate change (763)
- Machine learning (595)
- Water quality (543)
- Chemistry (527)
- Western Australia (507)
-
- Grazing (435)
- Nitrogen (428)
- Sustainability (418)
- Conservation (407)
- Biodiversity (371)
- Ecology (356)
- Management (295)
- Remote sensing (289)
- Humans (288)
- Deep learning (279)
- Machine Learning (274)
- Invasive species (273)
- Environment (269)
- Nanoparticles (255)
- United States (255)
- Phosphorus (253)
- Water (244)
- Soil (234)
- Phytoplankton (232)
- Synthesis (232)
- Agriculture (231)
- Oceanography (227)
- Biology (225)
- Artificial intelligence (224)
- Cancer (224)
- Publication Year
- Publication
-
- IGC Proceedings (1977-2023) (9261)
- Theses and Dissertations (2478)
- Electronic Theses and Dissertations (1482)
- Nebraska Tractor Tests (1347)
- United States Department of Agriculture Wildlife Services: Staff Publications (1276)
-
- Turkish Journal of Chemistry (1183)
- Faculty Publications (1075)
- School of Natural Resources: Faculty Publications (957)
- USF Tampa Graduate Theses and Dissertations (820)
- Dissertations (702)
- LSU Doctoral Dissertations (602)
- Chemistry Faculty Publications (570)
- Honors Theses (555)
- Theses (544)
- Graduate Theses and Dissertations (528)
- United States Geological Survey: Staff Publications (521)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (505)
- Chulalongkorn University Theses and Dissertations (Chula ETD) (495)
- LSU Master's Theses (493)
- Research Collection School Of Computing and Information Systems (488)
- The Prairie Naturalist (483)
- Masters Theses (480)
- Open Access Theses & Dissertations (474)
- Turkish Journal of Electrical Engineering and Computer Sciences (461)
- Dissertations and Theses (433)
- Journal of the Iowa Academy of Science: JIAS (406)
- OES Faculty Publications (406)
- UNLV Theses, Dissertations, Professional Papers, and Capstones (391)
- Articles (382)
- School of Earth, Environmental, & Marine Sciences Faculty Publications (371)
- Publication Type
Articles 77311 - 77340 of 78534
Full-Text Articles in Entire DC Network
The Utilization Of High Sensitivity Noble Gas Mass Spectrometry In The Detection Of Iodine-129 And Plutonium-244, Mervet S. Boulos
The Utilization Of High Sensitivity Noble Gas Mass Spectrometry In The Detection Of Iodine-129 And Plutonium-244, Mervet S. Boulos
Doctoral Dissertations
"Mass spectrometric analysis of the xenon isotopes in natural gas wells demonstrates that radioactive isotopes of element number 53 (I) and element number 94 (Pu) were present at the time of the Earth's formation. Evidence for the now extinct nuclide129I (t1/2 = 17 x 106 years) was found in CO₂ -rich gas while evidence for the now extinct 244Pu (t1/2 = 82 x 106 years) was discovered in other natural gas wells. The amounts of 129I in thyroids was measured by combining neutron activation analysis with noble gas mass spectrometry. The current …
Un Aselle Cavernicole D'Espagne Méridionale: Proasellus Solanasi N.Sp. (Crustacea, Isopoda, Asellota), Jean-Paul Henry, Guy Magniez
Un Aselle Cavernicole D'Espagne Méridionale: Proasellus Solanasi N.Sp. (Crustacea, Isopoda, Asellota), Jean-Paul Henry, Guy Magniez
International Journal of Speleology
Description of a new, unpigmented and eyeless species of the genus Proasellus Dudich, from an underground stream in the province of Malaga (Southern Spain). It belongs to the phyletic line which gave rise to the modem epigean water-slater Proasellus rneridianus (Racovitza).
A Propos Du Stenasellus Laticarpus Birstein (Crustacea Isopoda Asellota), Guy Magniez
A Propos Du Stenasellus Laticarpus Birstein (Crustacea Isopoda Asellota), Guy Magniez
International Journal of Speleology
The species Stenasellus laticarpus Birstein is closely related to three west-African Stenasellidae, forming the genus Magniezia Lanza. It belongs to the same genus: Stenasellus laticarpus = Magniezia laticarpa (Birstein).
Untersuchungen Über Das Nervensystem Von Hexaurus Merkli J. Frivaldzsky (Coleoptera, Bathysciinae), Michail Kwartirnikov
Untersuchungen Über Das Nervensystem Von Hexaurus Merkli J. Frivaldzsky (Coleoptera, Bathysciinae), Michail Kwartirnikov
International Journal of Speleology
The central nervous system of the beetle Hexaurus merkli J. Frivaldzsky corresponds to the formulae 2+2 / 0. The relative proportion of the corpora pedunculata reaches 5.5% and that of the olfactive lobes 6.8% of the total mass of the upper-exophagus ganglion. The under-exophagus ganglion corresponds to 29.5% of the total mass of the head-ganglion. It is furthermore demonstrated both in the upper- and under-exophagus ganglion that neurosecretory cells exist. Corpora allata and corpora cardiaca are also present.
On The Food And Feeding Habits Of Lepidomysis Longipes (Pillai & Mariamma) (Crustacea Mysidacea), C. N. Nath, N. K. Pillai
On The Food And Feeding Habits Of Lepidomysis Longipes (Pillai & Mariamma) (Crustacea Mysidacea), C. N. Nath, N. K. Pillai
International Journal of Speleology
The amount of food available to the subterranean mysid, Lepidomysis longipes (Pillai & Mariamma, 1964) in its habitat has been calculated and analysed. Lepidomysis appears to feed mainly on decaying vegetable matter. Lepidomysis shows many modifications in its external morphology. Consequently, the mode of feeding has undergone some marked changes from that of its epigean relatives. L. longipes is a discontinuous feeder.
Optic Regression In A Subterranean Mysid (Crustacea, Mysidacea), C. N. Nath, D. M. Thampy, N. K. Pillai
Optic Regression In A Subterranean Mysid (Crustacea, Mysidacea), C. N. Nath, D. M. Thampy, N. K. Pillai
International Journal of Speleology
The eyes of the blind subterranean mysid, Lepidomysis longipes are stalked and paired in the embryonic condition. They fuse together in the adult and the optic ganglia are enclosed in a single eyeplate. The ganglia are arranged in the form of an arc on either side anterodorsal to the brain inside the single eyeplate.
Les Japygidés Cavernicoles De La Faune Française, Jean Pagés
Les Japygidés Cavernicoles De La Faune Française, Jean Pagés
International Journal of Speleology
Twelve species of Japygids are cites from France. Six are known with certitude from caves. None of them shows any morphological modification which can be ascribed to cavernicolous life. All of them are found outside caves except Metaj. doderoi Silv. which is known from a unique female from Castel Mouly cave. To take into account the selection which seems to occur among the species, the term “subtroglophile” is proposed to include those which can be found in the caves.
Note On Lepidoptera From Bulgarian Caves, Andrzej W. Skalski
Note On Lepidoptera From Bulgarian Caves, Andrzej W. Skalski
International Journal of Speleology
This paper is a report on Lepidoptera collected in 1960 and 1970 in some caves of the Lakatnik region in the Stara Planina Mts. (Bulgaria). The following species were found: Digitivalva granitella (Tr.), D. pulicariae (Klim.), Thiphosa sabaudiata Dup. and Autophila limbata Stgr. Two species, D. pulicariae (Klim.) and A. limbata Stgr. are new for the cave-fauna and fauna of Bulgaria.
Observations Sur Un Aselle Obscuricole De France: Proasellus Racovitzai N.Sp. (Crustacea Isopoda Asellota), Jean-Paul Henry, Guy Magniez
Observations Sur Un Aselle Obscuricole De France: Proasellus Racovitzai N.Sp. (Crustacea Isopoda Asellota), Jean-Paul Henry, Guy Magniez
International Journal of Speleology
This paper reports the description of a new species of the genus Proasellus Dudich. Proasellus racovitzai n.sp. is widely depigmented. The eyes are reduced. It lives in the underground stream of the Goueil-di-Her cave system (Haute-Garonne, France). The species is an old, endemic form of the phyletic line of the modern epigean species P. meridianus (Racovitza). Chromosome number of the new species: 2n = 22.
The Evolution Of The Eastern North American Isopods Of The Genus Asellus (Crustacea: Asellidae). Part I, Laurence E. Fleming
The Evolution Of The Eastern North American Isopods Of The Genus Asellus (Crustacea: Asellidae). Part I, Laurence E. Fleming
International Journal of Speleology
This paper is the first in a three part series concerned with the evolution of North American isopods of the genus Asellus. It contains the descriptions of four new species of isopods and a list of pertinent new range data of presently known species.
Biospeologica Sovietica L: Une Nouvelle Espèce Cavernicole De Harpolithobius (Chilopoda, Lithobiidae) Du Caucase, Harpolithobius Birsteini N.Sp., N. T. Zalesskaja
Biospeologica Sovietica L: Une Nouvelle Espèce Cavernicole De Harpolithobius (Chilopoda, Lithobiidae) Du Caucase, Harpolithobius Birsteini N.Sp., N. T. Zalesskaja
International Journal of Speleology
A new troglobite species belonging to the genus Harpolithobius has been discovered during a recent biological exploration of Caucasian caves; 1 male and 2 females were collected in Avidzba cave and are described here. Harpolithobius birsteini n.sp. is the second troglobiotic Lithobiid known from Soviet caves. The other species collected must be considered as mere troglophilous.
Temperature And Relative Humidity Responses Of Two Texas Cave-Adapted Millipedes, Cambala Speobia (Cambalida: Cambalidae) And Speodesmus Bicornourus (Polydesmida: Vanhoeffeniidae), Eddie Bull, Robert W. Mitchell
Temperature And Relative Humidity Responses Of Two Texas Cave-Adapted Millipedes, Cambala Speobia (Cambalida: Cambalidae) And Speodesmus Bicornourus (Polydesmida: Vanhoeffeniidae), Eddie Bull, Robert W. Mitchell
International Journal of Speleology
The temperature and relative humidity preferences and tolerances of two Texas species of cave-adapted millipedes, Cambala speobia (Chamberlin) and Speodesmus bicornourus Causey, were studied. Both species showed gross preferences when tested in gradient chambers for temperatures and relative humidities approximating those of their cave environments. But C. speobia, the less adapted species morphologically, was the more selective of the two species for such conditions. S. bicornourus was far less tolerant of elevated temperatures and reduced relative humidities than was C. speobia. Discussed is a possible reason why a terrestrial troglobite like S. bicornourus would combine intolerance with a …
Biométrie Spatiale Dans L'Écosystème Souterrain: Répartition De Meta Menardi Latr. (Argiopidae), R. R. Tercafs
Biométrie Spatiale Dans L'Écosystème Souterrain: Répartition De Meta Menardi Latr. (Argiopidae), R. R. Tercafs
International Journal of Speleology
The spatial distribution of 113 individuals from the species Meta menardi Latr. (Argiopidae) divided in 10 different populations living in 8 Belgian caves has been studied. A grouping test and the calculation of R according to Clark et Evans (1954), based on the measurement of the distance to the nearest neighbour, have been used. Results show that the individuals are distributed at random inside their biotope.
Conflicts In Water Managment, A. Alvin Bishop
Conflicts In Water Managment, A. Alvin Bishop
Faculty Honor Lectures
Today we hear a lot about the "quality of life" and the "quality of the environment," two terms that everyone understands, but as yet no one has defined. Like others, I will not attempt a definition but introduce my subject by saying that water is intimately tied up with both our life and our environment, and its management has a profound effect for good or bad, depending upon the point of view. Today also, clean water and anti-pollution are popular crusades. Someone or something has to be responsible and engineering and science are convenient scapegoats. Considerable emotionalism is involved and …
Metabolic Role Of Sulfates And Sulfides Producing Bacteria In Pollution Of Waters, M. I. H. Aleem
Metabolic Role Of Sulfates And Sulfides Producing Bacteria In Pollution Of Waters, M. I. H. Aleem
KWRRI Research Reports
Cytochrome transport particles from Nitrobacter catalyzed nitrite, ascorbate as well as NADH oxidation with concomitant phosphate esterification yielding P/0 ratios of 1.0, 0.6 and 2.0 respectively. Phosphorylation coupled to nitrite oxidation was not effected by rotenone, amytal or antimycin while 50 and 70% inhibition of the NADH-linked phosphorylation was observed in the presence of HOQNO and rotenone respectively. Cell-free extracts from Nitrobacter also catalyzed an energy-dependent reduction of NAD+ by nitrite. The reduction of cytochrome c by NŌ2 was energy-dependent which involved the reversal of electrons from cytochrome a1. The subsequent energy-linked reduction of the flavoproteins …
The Prairie Naturalist Vol. 3, Nos. 3 And 4. September-December, 1971
The Prairie Naturalist Vol. 3, Nos. 3 And 4. September-December, 1971
The Prairie Naturalist
EDITORIAL: Badlands-Old and New ▪ Paul B. Kannowski
SEASONAL INVESTIGATIONS OF ALGAE FROM DEVILS LAKE, NORTH DAKOTA ▪ Richard Verch and Dean W. Blinn
THE VASCULAR FLORA OF PEMBINA COUNTY, NORTH DAKOTA ▪ Rays E. Willenbring and William T. Barker
LET'S EAT WILD ▪ Alan M. Cvancara
SURF SCOTER IN NORTH DAKOTA ▪ Harold A. Kantrud
SNOW GOOSE-CANADA GOOSE HYBRIDS ▪ David C. McGlauchlin
NOTES
Cowbird parasitism of an upland plover nest ▪ Kenneth F. Higgins
Birds sighted within one hour from one observation point in Burleigh County, North Dakota ▪ William A. Buresh
Golden-winged warbler in Burleigh County, North …
The Ias Bulletin, V5n6, November 1971, Iowa Academy Of Science
The Ias Bulletin, V5n6, November 1971, Iowa Academy Of Science
IAS Bulletin
In this issue:
--- Officers, Directors, and Section Chairmen, 1971-72
--- An Open Letter from the President to the Members of the Iowa Academy of Science
--- Manuscripts for the Proceedings Invited
--- News from the Fall Directors' Meeting
--- Plans for 1972 Spring Meeting Shaping Up
--- Call for Papers for the 1972 Spring Meeting
--- Archeology Section Now Anthropology Section
--- What Ever Became of the Articulation Effort?
--- Future Meetings of the Academy
--- Geology Monograph Widely Distributed
--- New Officers of ISTS
--- Special Summer Study Opportunity Available
--- Do-It-Yourself Kit for Activists
--- 56% of …
Water Resources News, Volume 3, No. 9, November 1971
Water Resources News, Volume 3, No. 9, November 1971
Water Current Newsletter
Program for the 1972 Interdisciplinary Seminar on Water Issues
Simulation of Groundwater Systems
Summer Short Course Planned
Recyling of Water
OSW Awards Freezing Plant Design Contract
Cloud-Seeding Program
Water Rights Study
"Turn-Key" Approach Proposed for Construction of Waste Treatment Plants
Water Quality Guidelines for Nation Being Updated by NAS for EPA
Nebraska Water Resources and Irrigation Development Seminar for the 1970s
EPA Names New Head of Solid Waste Programs Office
Symposium on Costs of Waster Pollution Control
Research Need
Symposium on Watershed Management
EPA Revising Regulations for Grants and Contracts
Internships in Science and Engineering
The Howard University Reviews Of Science, Vol 1 No 1, Department Of Physics
The Howard University Reviews Of Science, Vol 1 No 1, Department Of Physics
Physics Faculty Publications
No abstract provided.
Report On Water Pollution Problems In Las Vegas Wash And Las Vegas Bay, Environmental Protection Agency
Report On Water Pollution Problems In Las Vegas Wash And Las Vegas Bay, Environmental Protection Agency
Publications (WR)
This report was prepared by the Federal Water- Quality Administration, Pacific Southwest Region, now the Environmental Protection Agency (EPA), Region IX, at the request of the State of Nevada, Department of Health, Welfare, and rehabilitation. In a letter, dated December 5, 1969, this agency asked for technical assistance, as authorized by the Federal Water Pollution Control Act, in developing discharge standards appropriate for Las Vegas Bay, Lake Mead, and the Lower Colorado River. The subsequent study was performed by EPA from January through August, 1970. The establishment of Nevada State Water Quality Standards for these waters will enable responsible officials …
Cellular Inactivation By Heavy Ions, Neutrons, And Pions, Robert Katz, S. C. Sharma, M. Hamayoonfar
Cellular Inactivation By Heavy Ions, Neutrons, And Pions, Robert Katz, S. C. Sharma, M. Hamayoonfar
Robert Katz Publications
The delta-ray theory of the inactivation of cells by energetic heavy ions describes cellular survival after heavy ion bombardment through a two-component survival model, in which 4 operational parameters (E0,m0, σ0, and κ) describe the response of a particular cellular variety in a particular ambient condition, for an arbitrary radiation environment. The quantities m and E0 are the extrapolation number and extrapolated D-37 dose of the survival curve after gamma-ray irradiation. The quantities σ0 and κ are found from the initial slope of survival curves after irradiation with ions of different LET, …
Ua77/1 Western Alumnus, Vol. 40, No. 2, Wku Alumni Relations
Ua77/1 Western Alumnus, Vol. 40, No. 2, Wku Alumni Relations
WKU Administration Documents
Quarterly magazine created for WKU alumni. Regular features are Hilltopics, Sports, Alumni Newsgrams and Notes and In Memoriam. This issue includes:
- Graduate School (College) is On Its Way
- Evening Class is Thataway
- The Hilltopper Hundred to the Rescue
- ETV - Keep Watching, It's All in Color
- Student Interns Learn How Government Works
- Significant Statements: The New Year Begins
- Good News for Fishermen: Reservoir Research
- There it Was! Your Homecoming - 1971
- Performing Arts Illuminate the Campus Scene
- Discovery 1 - Uncovering the Kentucky of Antiquity
- Discovery 2 - Reviving the Heritage of Kentucky
- Discovery 3 - The Intercultural Studies Program …
A Preliminary Ecological Study Of Areas To Be Impounded In The Salt River Basin Of Kentucky, Louis A. Krumholz, Stuart E. Neff, Edmond J. Bacon, Jerry S. Parsons, John D. Woodling
A Preliminary Ecological Study Of Areas To Be Impounded In The Salt River Basin Of Kentucky, Louis A. Krumholz, Stuart E. Neff, Edmond J. Bacon, Jerry S. Parsons, John D. Woodling
KWRRI Research Reports
This report includes work that is an extension of Project No. B-005-KY as reported in Research Report No. 43 of the University of Kentucky Water Resources Institute. That project was initiated in April 1968 as Project No. A-019-KY with principal emphasis on physical, chemical, and biological characteristics of the main stem of the Salt River upstream from the proposed damsite for Taylorsville Lake, an impoundment of about 3, 600 acres at seasonal pool. The report includes descriptions of an additional 13 stations along the stream, bringing to 38 the number of permanent collecting sites.
Values for dissolved oxygen ranged from …
The Ias Bulletin, V5n5, September 1971, Iowa Academy Of Science
The Ias Bulletin, V5n5, September 1971, Iowa Academy Of Science
IAS Bulletin
In this issue:
--- Officers, Directors, and Section Chairmen, 1971-72
--- Proceedings Progress
--- Business Manager for Proceedings Appointed
--- Submit Manuscripts for Proceedings at Any Time
--- Iowa Science Teachers Journal Will Have Limited Distribution
--- Staff Changes at Drake Involve Academy "Activists"
--- Status of the Iowa State Preserves Advisory Board Uncertain
--- Darling Foundation Issues Catalog of Conversation Education Facilities
--- Are you a Member of AAAS?
--- AAAS Research Grants Awarded
--- AAAS Governance Changes Being Proposed
--- Guide to Upper Iowa River Published By George Knudson of Luther College
--- AAPT-Iowa Section
--- Student Programs …
A Preliminary Ecological Study Of Areas To Be Impounded In The Salt River Basin Of Kentucky, Louis A. Krumholz
A Preliminary Ecological Study Of Areas To Be Impounded In The Salt River Basin Of Kentucky, Louis A. Krumholz
KWRRI Research Reports
This report covers work that is an extension of Project No. A-019-KY. A series of 25 sampling stations was established in the mainstream and tributaries of the Salt River that extend from the source of the stream in Boyle County to a few miles below the site of Taylorsville Darn in Spencer County. Sampling for water chemistry and biota was carried out semimonthly. Data on temperature, oxygen, depth, and discharge, along with analyses for cations (Ca, Mg, Fe, Mn) and anions (PO4, NO3, NO2, CO3, HCO3) have been accumulated and …
Water Resources News, Volume 3, No. 7, September 1971
Water Resources News, Volume 3, No. 7, September 1971
Water Current Newsletter
Irrigation and Drainage Specialty Conference
First Annual Meeting of the Nebraska Section of the American Water Resources Association
Amendments to Water Resources Research Act
Testified That Corps Would Benefit from New Department of Natural Resources
Industries Must File Permit Applications or Face Legal Action
Price of Air and Water Pollution Clean-Up at $105 Billion
UCOWR Annual Meeting
Senate Subcommittee Approves Water Pollution Control Legislation
Rhode Island Researchers Propose Beneficial Use of Waste Heat
Lake Tahoe Study
13th Annual Rocky Mountain Spectroscopy Conference
13th Annual Rocky Mountain Spectroscopy Conference
Rocky Mountain Conference on Magnetic Resonance
Program and abstracts from the 13th annual meeting of the Rocky Mountain Spectroscopy Conference, hosted by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 9-10, 1971.
A Study Of Phytoplankton Dynamics In Lake Fayetteville As A Means Of Assessing Water Quality, Richard L. Meyer
A Study Of Phytoplankton Dynamics In Lake Fayetteville As A Means Of Assessing Water Quality, Richard L. Meyer
Arkansas Water Resources Center Technical Reports
Phytoplankton community was analyzed for seasonal and vertical distribution in Lake Fayetteville. This northwest Arkansas reservoir maintains a stable water level and chemical input with a relatively constant, slow overflow. Its source is groundwater seepage through a calcareous substrate with little contribution from the limited drainage basin. Phytoplankton community development with its associations and assemblages, chlorophylls -a, -b and c, and biomass distribution are described. The seasonal cycles of the chemical parameters NH4-N, NO2-N, NO3-N, ortho-phosphate, silicon, pH, HCO3- and total-alkalinity plus oxygen are described and discussed. The physical parameters of temperature, light and climate are included. The interaction of …
A Study Of A Divalent Cation-Selective Electrode, William Stanhope Ryan Jr.
A Study Of A Divalent Cation-Selective Electrode, William Stanhope Ryan Jr.
Master's Theses
The ion-selective membrane electrode, recently introduced commercially, has shown excellent promise as a tool for determining ionic activities and concentrations in solution. It was the intent of the author to study the Orion divalent cation-selective electrode with two objectives.
The first objective of this research was to characterize the response of the divalent cation-selective electrode to calcium and magnesium ions in aqueous solutions. The effect of anions, monovalent cations; and pH upon this response was investigated. An examination was made of the response of this electrode to other divalent cations and of the effect of organic solvents on the membrane …
A Comparative Investigation Of The Effects Of Frequent Testing Upon Achievement In Secondary Advanced Algebra, John Thomas Fullerton
A Comparative Investigation Of The Effects Of Frequent Testing Upon Achievement In Secondary Advanced Algebra, John Thomas Fullerton
All Master's Theses
Relatively speaking, few studies have concerned themselves with the problem of frequent testing, and as Keys pointed out, empirical evidence, uncomplicated by differences in the amount of testing material employed, on the effects of frequent testing is, at best, scarce (14:427). Also many studies used tests and test results for direct instruction, thus introducing additional variables. Furthermore, the choice of subjects and disciplines has been limited, the better part being taken from college psychology and sociology classes or high school science classes. This investigation was not an attempt to modify previous experiments, nor was it an attempt to identify which …