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University of Northern Iowa

1997

Articles 31 - 47 of 47

Full-Text Articles in Physical Sciences and Mathematics

Book Review - Okoboji Wetlands. A Lesson In Natural History, Robert W. Black Jan 1997

Book Review - Okoboji Wetlands. A Lesson In Natural History, Robert W. Black

Journal of the Iowa Academy of Science: JIAS

Michael Lannoo's reverent, musing history of the Okoboji region, and especially its wetlands and the Iowa Lakeside Laboratory, is a uniquely structured, well-written and wonderfully illustrated introduction to a distinct region in Iowa, a rich natural history of wetland organisms and a relatively unexplored branch of environmental ethics. Lannoo draws upon many years of experience in this region, as a student, researcher and teacher, and the wonderful resources of the Iowa Lakeside Laboratory and the Iowa Great Lakes Maritime Museum to produce a volume that educates the reader of the history and natural history of the Okoboji region and provokes …


Editorial Board & Iowa Academy Of Science Officers And Directors Jan 1997

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Front Matter Jan 1997

Front Matter

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


The Contributions Of J. A. Udden To An Understanding Of Iowa Geology, Richard C. Anderson Jan 1997

The Contributions Of J. A. Udden To An Understanding Of Iowa Geology, Richard C. Anderson

Journal of the Iowa Academy of Science: JIAS

Johan August Udden served on the faculty of Augustana College from 1888 until 1911. His research during that time was directed toward an understanding of the geology of areas close at hand, the region around Rock Island and nearby areas in Iowa and Illinois. Udden's most significant contributions to Iowa geology were in his treatment of 1) Paleozoic, Cretaceous, and Quaternary stratigraphy; 2) subsurface geology, including information on bedrock elevations and topography; 3) characteristics and origin of the loess. Most of this information was included in the Annual Reports of the Iowa Geological Survey published between 1899 and 1903. He …


Index For Volume 104 Jan 1997

Index For Volume 104

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Fungal Colonization Of Alfalfa Stubble Following Harvest, J. K. O'Mara, G. P. Munkvold Jan 1997

Fungal Colonization Of Alfalfa Stubble Following Harvest, J. K. O'Mara, G. P. Munkvold

Journal of the Iowa Academy of Science: JIAS

Two-year-old stands of alfalfa cultivars Saranac and Vernal, planted in Central Iowa, were sampled 0, 15, and 30 days after the first harvest in 1995 to identify fungi colonizing the stubble left after harvest and evaluate the role of harvest-induced wounds as infection sites for potential crown-rotting fungi. Analysis of variance was conducted to determine if sampling date and cultivar significantly affected incidence of the fungi. All stems were infected with at least one fungal species at every sampling dare. The fungal genera most frequently isolated were Alternaria, Colletotrichum, Fusarium, Phoma, and Rhizoctonia. Fusarium acuminatum was the most frequently isolated …


Carnivorous Spadefoot (Spea Bombifrons Cope) Tadpoles And Fairy Shrimp In Western Iowa, Eugenia S. Farrar, Jane D. Hey Jan 1997

Carnivorous Spadefoot (Spea Bombifrons Cope) Tadpoles And Fairy Shrimp In Western Iowa, Eugenia S. Farrar, Jane D. Hey

Journal of the Iowa Academy of Science: JIAS

Amphibian larval polymorphisms, rarely found in the Midwest, are more common in arid western regions. We have discovered that Plains spadefoot toad, Spea bombifrons Cope, tadpoles occur as carnivorous and omnivorous morphological forms in flooded soybean and corn fields on the Missouri River flood plain of western Iowa. Carnivores have longer snouts, larger beaks with an upper cusp and lower notch, shorter intestines with fewer loops than the omnivores, and they feed on fairy shrimp. A similar polymorphism in Spea multiplicata Cope enhances survival in the desert because the carnivore develops faster after consuming fairy shrimp and is able to …


A Search For Average, Extremes, And Runs Of Unusual Weather In Iowa, R. E. Carlson, D. P. Todey Jan 1997

A Search For Average, Extremes, And Runs Of Unusual Weather In Iowa, R. E. Carlson, D. P. Todey

Journal of the Iowa Academy of Science: JIAS

Temperature and precipitation during the past decade have exhibited wide variation throughout Iowa. Is this unusual? An attempt was made to answer this question by computing various statistical parameters that characterize variation in Iowa's long term climatic record. Absolute deviations were used to identify the most and least variable months and years since 1900. Overall, 1936 with a very cold winter and very warm summer was the least normal year. Runs of daily weather showed that heat and cold stress could often persist for more than 1 month. Runs of dry days were much longer than runs of wet days. …


Cover - Table Of Contents Jan 1997

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Front Matter Jan 1997

Front Matter

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Front Matter Jan 1997

Front Matter

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Photo, Dr. Richard W. Pohl, February 1982 & Foreward To V.104 No.3, Lynn G. Clark Jan 1997

Photo, Dr. Richard W. Pohl, February 1982 & Foreward To V.104 No.3, Lynn G. Clark

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Cover - Table Of Contents Jan 1997

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Nesting Status Of The Cooper's Hawk In Iowa: 1988-1996, David. J. Conrads Jan 1997

Nesting Status Of The Cooper's Hawk In Iowa: 1988-1996, David. J. Conrads

Journal of the Iowa Academy of Science: JIAS

The Cooper's Hawk was once considered a common nesting species in Iowa. Organochlorine pesticides and their residues, along with habitat loss contributed to its decline throughout the Midwest after the 1940's. This species was classified as endangered in Iowa in 1984, but recent trends in nests found indicate that the population of these hawks has increased. Since April 1988, 53 nests have been discovered in Iowa. Due to the apparent population growth, this species was removed from Iowa's endangered species list in 1994.


Awards And Recognition, Iowa Academy Of Science, 1997 Jan 1997

Awards And Recognition, Iowa Academy Of Science, 1997

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Editorial Board & Iowa Academy Of Science Officers And Directors Jan 1997

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Fuzzy Logic: An Analysis Of Logical Connectives And Their Characterizations, John F. Hamman Jan 1997

Fuzzy Logic: An Analysis Of Logical Connectives And Their Characterizations, John F. Hamman

Dissertations and Theses @ UNI

The focus of this thesis is to determine exactly which functions serve as appropriate fuzzy negation, conjunction and disjunction functions. To this end, the first chapter serves as motivation for why fuzzy logic is needed, and includes an original demonstration of the inadequacy of many valued logics to resolve the sorites paradox. Chapter 2 serves as an introduction to fuzzy sets and logic. The canonical fuzzy set of tall men is examined as a motivating example, and the chapter concludes with a discussion of membership functions.

Four desirable conditions of the negation function are given in Chapter 3, but it …