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Life Sciences

2001

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Articles 301 - 318 of 318

Full-Text Articles in Physical Sciences and Mathematics

Invertebrate Egg And Plant Seed Banks In Natural, Restored, And Drained Wetlands In The Prairie Pothole Region (Usa) And Potential Effects Of Sedimentation On Recolonization Of Hydrophytes And Aquatic Invertebrates, Robert Andrew Gleason Jan 2001

Invertebrate Egg And Plant Seed Banks In Natural, Restored, And Drained Wetlands In The Prairie Pothole Region (Usa) And Potential Effects Of Sedimentation On Recolonization Of Hydrophytes And Aquatic Invertebrates, Robert Andrew Gleason

Electronic Theses and Dissertations

Sediment is the major pollutant of wetlands, lakes, rivers, and estuaries in the United States and it poses unique threats to wetlands of the Prairie Pothole Region (PPR). Sediment may impact the success of wetland restorations because burial of invertebrate and plant propagules may impact hatching and germination success, and hence, may hamper successional changes throughout interannual climate cycles. Sedimentation also reduces the pool depth and volume, further exacerbating the recovery of hydrophyte communities in restored wetlands. I evaluated the potential impacts of sedimentation on prairie wetlands from several perspectives. First, I evaluated the effects of sedimentation on loss of …


The Status And Distribution Of The Topeka Shiner Notropis Topeka In Eastern South Dakota, Carmen M. Blausey Jan 2001

The Status And Distribution Of The Topeka Shiner Notropis Topeka In Eastern South Dakota, Carmen M. Blausey

Electronic Theses and Dissertations

The Topeka shiner Notropis topeka is a small (< 75 mm) minnow that inhabits prairie streams in several north central plains states. Once widespread and abundant throughout its historic range, the Topeka shiner is now found only in isolated populations. Because of an 80% reduction in occurrence throughout their range, the U.S. Fish and Wildlife Service listed the Topeka shiner as endangered in January 1999. At the time, limited information on habitat preferences and dist1ibution existed for this species in South Dakota. The objectives of this study were to measure local habitat features and water quality conditions at the reach scale at Topeka shiner study sites, create a model using these data to determine favorable habitat conditions, and identify fish species commonly associated with Topeka shiners. Fish and habitat data were collected at 61 tributary sites of the James, Vermillion, and Big Sioux rivers from June through September in 1999 and 2000. Sample sites in 1999 were based on historic Topeka shiner records in the South Dakota Natural Heritage Database. Sample sites in 2000 were based on a draft GIS model identifying potential Topeka shiner streams. Fish were collected with seines between block nets and standard procedures were used to measure physical and hydrological features of stream reaches. Cyprinids dominated the fish community for each river basin during both sample years. Insectivores and omnivores were the dominant trophic classes for each river basin for both sample years. Fish community associations for Topeka shiners were based on two stepwise logistic regression models: abundance of individual species at each site and presence or absence of individual species at each site. The abundance model indicated that Topeka shiners were most commonly associated with orangespotted sunfish Lepomis lutrenis and tadpole madtoms Noturns gyrinus. The presence/absence model showed that Topeka shiners were typically associated with red shiners Notropis lutrenis, tadpole madtoms Noturns gyrinus, black bullheads Ameiurus melas, and bigmouth shiners Notropis dorsalis. Habitat preferences were based on three stepwise logistic regression models: physical habitat water quality, and substrate composition at the reach scale. The physical habitat model indicated that Topeka shiners are associated with stream reaches that had low animal use, overhanging vegetation, stream bank vegetation comprised of sedges/rushes, low depositional zones, and run macrohabitat. The water quality model did not indicate any favorable or preferred conditions. The substrate model indicated that Topeka shiners are associated with stream reaches that had fine gravel or cobble substrates. The results of my study will lead to a better understanding of Topeka shiner distribution and habitat, and aid federal and state agencies in making management decisions that provide for protection and preservation of this species.


Trachelomonas Spp. And Other Euglenophyceae Taxa In A Southeastern Virginia Lake, Harold G. Marshall Jan 2001

Trachelomonas Spp. And Other Euglenophyceae Taxa In A Southeastern Virginia Lake, Harold G. Marshall

Biological Sciences Faculty Publications

Trachelomonas species from Lake Kilby, a reservoir lake in southeastern Virginia are described with supportive electron micrographs. The most abundant Trachelomonas species were T. hispida and T. volvocina. Other members of the Euglenophyceae occurring in this lake are identified.


Classification And Identification Of Pfiesteria And Pfiesteria-Like Species, Karen Steidinger, Jan Landsberg, R. William Richardson, Earnest Truby, Barbara Blakesley, Paula Scott, Patricia Tester, Torstein Tengs, Patrice Mason, Stever Morton, David Seaborn, Wayne Litaker, Kimberly Reece, David Oldach, Leonard Haas, Gerardo Vasta Jan 2001

Classification And Identification Of Pfiesteria And Pfiesteria-Like Species, Karen Steidinger, Jan Landsberg, R. William Richardson, Earnest Truby, Barbara Blakesley, Paula Scott, Patricia Tester, Torstein Tengs, Patrice Mason, Stever Morton, David Seaborn, Wayne Litaker, Kimberly Reece, David Oldach, Leonard Haas, Gerardo Vasta

Biological Sciences Faculty Publications

Dinoflagellates can be classified both botanically and zoologically; however, they are typically put in the botanical division Pyrrhophyta. As a group they appear most related to the protistan ciliates and apicomplexans at the ultrastructure level. Within the Pyrrhophyta are both unarmored and armored forms of the dominant, motile flagellated stage. Unarmored dinoflagellates do not have thecal or wall plates arranged in specific series, whereas armored species have plates that vary in thickness but are specific in number and arrangement. In armored dinoflagellates, the plate pattern and tabulation is a diagnostic character at the family, subfamily, and even genus levels. In …


The 6th International Conference And Workshop On Lobster Biology And Management: An Introduction, Mark J. Butler Iv Jan 2001

The 6th International Conference And Workshop On Lobster Biology And Management: An Introduction, Mark J. Butler Iv

Biological Sciences Faculty Publications

Every three years or so, the International Conference and Workshop on Lobster Biology and Management (ICWL) brings together lobster scientists, fishery managers, and industry representatives from around the world for a week of scientific presentations, workshops, and discussions on lobster biology and management. The first ICWL was held in Perth, Australia, in January 1977. Its purpose was to bring together a small group of lobster researchers from the USA and Australia to discuss common issues and themes. That initial workshop spawned a continuing series of meetings that have become the international lobster conference for scientists—the equivalent of an international congress …


The Impact Of Marine Reserves On Exploited Species With Complex Life Histories: A Modeling Study Using The Caribbean Spiny Lobster In Exuma Sound, Bahamas, William T. Stockhausen Jan 2001

The Impact Of Marine Reserves On Exploited Species With Complex Life Histories: A Modeling Study Using The Caribbean Spiny Lobster In Exuma Sound, Bahamas, William T. Stockhausen

Dissertations, Theses, and Masters Projects

Most benthic invertebrates and reef-associated fish undergo a dispersive, planktonic larval stage prior to settlement and metamorphosis into the juvenile and adult stages. In some species, settlement may be decoupled from adult abundance at local spatial scales if hydrodynamic conditions or larval behavior do not promote local retention. Similarly, spatial variability in postsettlement mortality or secondary dispersal by juveniles and adults may decouple spatial patterns of adult abundance from those of settlement. as a consequence, spatial patterns of settlement and adult abundance may be functionally related in a complex fashion. Whether biotic/environmental factors control spatial patterns of abundance may have …


Morphological Variation Of Three Populations Of The Veined Rapa Whelk, Rapana Venosa, An Invasive Predatory Gastropod Species, Rebecca A. Green Jan 2001

Morphological Variation Of Three Populations Of The Veined Rapa Whelk, Rapana Venosa, An Invasive Predatory Gastropod Species, Rebecca A. Green

Dissertations, Theses, and Masters Projects

No abstract provided.


Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, John R. Foster Jan 2001

Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, John R. Foster

Dissertations, Theses, and Masters Projects

No abstract provided.


A Descriptive Study Of The Reproductive Biology Of The Veined Rapa Whelk (Rapana Venosa) In The Chesapeake Bay, Erica S. Westcott Jan 2001

A Descriptive Study Of The Reproductive Biology Of The Veined Rapa Whelk (Rapana Venosa) In The Chesapeake Bay, Erica S. Westcott

Dissertations, Theses, and Masters Projects

No abstract provided.


Reproductive Biology Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay, Elizabeth Shaw Watkins Jan 2001

Reproductive Biology Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay, Elizabeth Shaw Watkins

Dissertations, Theses, and Masters Projects

No abstract provided.


Before And After Riparian Management: Sediment And Nutrient Exports From A Small Agricultural Catchment, Western Australia, Lucy Mckergow, David Weaver, I Prosser, R Grayson, A. E.G. Reed Jan 2001

Before And After Riparian Management: Sediment And Nutrient Exports From A Small Agricultural Catchment, Western Australia, Lucy Mckergow, David Weaver, I Prosser, R Grayson, A. E.G. Reed

Conference papers and presentations

Riparian vegetation can trap sediment and nutrients coming from hillslopes and reduce stream bank erosion. This study presents results from a 10 year stream monitoring program in a small agricultural catchment near Albany, Western Australia. In 1996, a 1.6 km stream reach was fenced, planted with eucalyptus species and managed separately from the adjacent paddocks. Stream flow, nutrient and sediment concentration data were collected at the downstream end of the fenced riparian area between 1991 and 2000, so there are data for the “before” and “after” riparian management periods. Suspended sediment concentrations fell dramatically following riparian management; the average event …


An Analysis Of A Radio Frequency Sensor As A Means To Remotely Sense Selected Surface Topographies In An Agriculture Environment, Barry Michael Alexia Jan 2001

An Analysis Of A Radio Frequency Sensor As A Means To Remotely Sense Selected Surface Topographies In An Agriculture Environment, Barry Michael Alexia

Dissertations and Theses @ UNI

Remote sensing is the science and art of obtaining information about an object, area or phenomenon through the analysis of data acquired by a device that is not in contact with the object, area, or phenomenon under investigation. The remotely sensed data can be of many forms, including variations in force distribution, acoustic wave distribution, or electromagnetic energy distribution.Information thus acquired can be used for observing,monitoring, and studying planetary surfaces and environments.

Because there are many ways to acquire data about targets of interest, there are many types of remote sensors that can be used, including visible, infrared, and active …


Distinguishing Natural Language Processes On The Basis Of Fmri-Measured Brain Activation, Francisco Pereira, Marcel Just, Tom Mitchell Dec 2000

Distinguishing Natural Language Processes On The Basis Of Fmri-Measured Brain Activation, Francisco Pereira, Marcel Just, Tom Mitchell

Marcel Adam Just

No abstract provided.


Mental Rotation Of Objects Retrieved From Memory: An Fmri Study Of Spatial Processing, Marcel Just, Patricia Carpenter, Mandy Maguire, Vaibhav Diwadkar, Stephanie Mcmains Dec 2000

Mental Rotation Of Objects Retrieved From Memory: An Fmri Study Of Spatial Processing, Marcel Just, Patricia Carpenter, Mandy Maguire, Vaibhav Diwadkar, Stephanie Mcmains

Marcel Adam Just

No abstract provided.


Interdependence Of Non-Overlapping Cortical Systems In Dual Cognitive Tasks, Marcel Adam Just, Patricia A. Carpenter, Timothy A. Keller, Lisa Emery, Holly Zajac, Keith R. Thulborn Dec 2000

Interdependence Of Non-Overlapping Cortical Systems In Dual Cognitive Tasks, Marcel Adam Just, Patricia A. Carpenter, Timothy A. Keller, Lisa Emery, Holly Zajac, Keith R. Thulborn

Marcel Adam Just

No abstract provided.


The Neural Bases Of Sentence Comprehension: A Fmri Examination Of Syntactic And Lexical Processing, Timothy A. Keller, Patricia A. Carpenter, Marcel Adam Just Dec 2000

The Neural Bases Of Sentence Comprehension: A Fmri Examination Of Syntactic And Lexical Processing, Timothy A. Keller, Patricia A. Carpenter, Marcel Adam Just

Marcel Adam Just

No abstract provided.


An Fmri Investigation Of Sentence Comprehension By Eye And By Ear: Modality Fingerprints On Cognitive Processes, Erica B. Michael, Timothy A. Keller, Patricia A. Carpenter, Marcel Adam Just Dec 2000

An Fmri Investigation Of Sentence Comprehension By Eye And By Ear: Modality Fingerprints On Cognitive Processes, Erica B. Michael, Timothy A. Keller, Patricia A. Carpenter, Marcel Adam Just

Marcel Adam Just

No abstract provided.


An Empirical Model Of Amino Acid Transformations In An Alpine Soil, David A. Lipson, Ted K. Raab, Steven K. Schmidt, Russ K. Monson Dec 2000

An Empirical Model Of Amino Acid Transformations In An Alpine Soil, David A. Lipson, Ted K. Raab, Steven K. Schmidt, Russ K. Monson

Ted K. Raab

Amino acids are potentially important nitrogen (N) sources for plants in many ecosystems. However, a quantitative understanding of organic N availability is lacking for most ecosystems. This study estimates seasonal amino acid fluxes in an alpine tundra soil using three independent data sets. In previous work in an alpine dry meadow ecosystem in the Front Range of the Colorado Rocky Mountains, we measured signifcant rates of amino acid production from soil peptides during the plant growing season. This suggested that proteolysis of native soil peptides could serve as a measure of amino acid availability to plants. Here we use a …