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Full-Text Articles in Physical Sciences and Mathematics

Visualizing Rhizosphere Chemistry Of Legumes With Mid-Infrared Synchrotron Radiation, Ted K. Raab, Michael C. Martin May 2001

Visualizing Rhizosphere Chemistry Of Legumes With Mid-Infrared Synchrotron Radiation, Ted K. Raab, Michael C. Martin

Ted K. Raab

A bright synchrotron light source operated by the Lawrence Berkeley National Laboratory served as an external source for infrared (IR) microscopy of plant root microcosms. Mid-IR light from synchrotrons is 2-3 orders of magnitude brighter than conventional sources, providing contrast based on the chemical information in the reflected signal at a spatial resolution near the diffraction-limit of 3-10 microns. In an experiment using plant root microcosms fitted with zinc selenide IR-transmissive windows (50 mm x 20 mm x 1 mm), we describe chemical differences and similarities within the root zone of mung bean (Vigna radiata L.), grown with or without …


N-Methyl-D-Aspartate Channel And Consciousness: From Signal Coincidence Detection To Quantum Computing, Armando F. Rocha, Alfredo Pereira Jr Jan 2001

N-Methyl-D-Aspartate Channel And Consciousness: From Signal Coincidence Detection To Quantum Computing, Armando F. Rocha, Alfredo Pereira Jr

Armando F Rocha

Research on Blindsight, Neglect/Extinction and Phantom limb syndromes, as well as electrical measurements of mammalian brain activity, have suggested the dependence of vivid perception on both incoming sensory information at primary sensory cortex and reentrant information from associative cortex. Coherence between incoming and reentrant signals seems to be a necessary condition for (conscious) perception. General reticular activating system and local electrical synchronization are some of the tools used by the brain to establish coarse coherence at the sensory cortex, upon which biochemical processes are coordinated. Besides electrical synchrony and chemical modulation at the synapse, a central mechanism supporting such a …


Phylogeographic Analysis Of The Threatened And Endangered Superconglutinate-Producing Mussels Of The Genus Lampsilis (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard, Paul D. Hartfield Jan 2001

Phylogeographic Analysis Of The Threatened And Endangered Superconglutinate-Producing Mussels Of The Genus Lampsilis (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard, Paul D. Hartfield

Kevin J. Roe

Several species of freshwater unionid mussels in the genus Lampsilis exhibit a remarkable reproductive strategy. Female mussels of these species enclose their larvae in a minnow-like lure, called a ‘superconglutinate’, to attract piscivorous fishes. When a fish attempts to ingest the superconglutinate the lure ruptures and the larvae are released to parasitize the fish. Of the four species of mussel which exhibit this strategy and are endemic to the Gulf Coast drainages of the southeastern United States, three are protected under the Endangered Species Act, and one is recognized as imperilled. Phylogenetic analysis of nucleotide sequences of the mitochondrial 16S …


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.


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 …