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2006

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Articles 1411 - 1440 of 5872

Full-Text Articles in Physical Sciences and Mathematics

How Magnetotactic Bacteria Make Magnetosomes Queue Up, Richard B. Frankel, Dennis A. Bazylinski Aug 2006

How Magnetotactic Bacteria Make Magnetosomes Queue Up, Richard B. Frankel, Dennis A. Bazylinski

Physics

Magnetotactic bacteria contain chains of magnetosomes that comprise a permanent magnetic dipole in each cell. In two separate, recent papers, Scheffel et al. and Komeili et al. describe the roles of the proteins MamJ and MamK in magnetosome chain formation. Here, we describe the two studies and highlight questions that must be addressed in future investigations of how magnetotactic bacteria construct their magnetic compass needles.

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The Harmonic Oscillator, The Hermite Polynomial Solutions, Carl W. David Aug 2006

The Harmonic Oscillator, The Hermite Polynomial Solutions, Carl W. David

Chemistry Education Materials

The Hermite polynomial solution to the simple harmonic oscillator is discussed.

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The Harmonic Oscillator, The Ladder Operator Solutions, Carl W. David Aug 2006

The Harmonic Oscillator, The Ladder Operator Solutions, Carl W. David

Chemistry Education Materials

The ladder operator approach to the quantum mechanics of the simple harmonic oscillator is presented.

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Integrated Fisheries Management Draft Allocation Report Roe's Abalone Perth Metropolitan Region., Integrated Fisheries Allocation Advisory Committee Aug 2006

Integrated Fisheries Management Draft Allocation Report Roe's Abalone Perth Metropolitan Region., Integrated Fisheries Allocation Advisory Committee

Fisheries management papers

The IFAAC has prepared this report, which documents the committee’s initial position on allocations for the abalone resource, along with the reasons for its conclusions as a basis for widespread community consultation. This report follows the IFAAC’s preliminary investigation of the abalone resourcesharing issues and consultation with stakeholders

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Manifestations Of Broken Symmetry: The Surfaces Phases Of Ca2−XSrXRuo4, Robert G. Moore Ii Aug 2006

Manifestations Of Broken Symmetry: The Surfaces Phases Of Ca2−XSrXRuo4, Robert G. Moore Ii

Doctoral Dissertations

The discovery of superconductivity in Sr2RuO4 has renewed vigor in the study of correlated electron systems. The evolution of a p-wave superconducting state from a para- magnetic 2-dimensional Fermi liquid shows the ruthenate superconductivity is anything but conventional. Sr2RuO4 is isostructural with La2CuO4, the parent compound for the high temperature superconducting family La2−xSrxRuO4. The substitution of Ca2+ for Sr2+ generates a different structure involving a static rotation and tilt of the RuO6 octahedral, however, the antiferromagnetic insulating ground state of Ca …

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Climate Variability Has A Stabilizing Effect On The Coexistence Of Prairie Grasses, Peter B. Adler, Janneke Hille Ris Lambers, Phaedon C. Kyriakidis, Qingfeng Guan, Jonathan M. Levine Aug 2006

Climate Variability Has A Stabilizing Effect On The Coexistence Of Prairie Grasses, Peter B. Adler, Janneke Hille Ris Lambers, Phaedon C. Kyriakidis, Qingfeng Guan, Jonathan M. Levine

School of Natural Resources: Faculty Publications

How expected increases in climate variability will affect species diversity depends on the role of such variability in regulating the coexistence of competing species. Despite theory linking temporal environmental fluctuations with the maintenance of diversity, the importance of climate variability for stabilizing coexistence remains unknown because of a lack of appropriate long-term observations. Here, we analyze three decades of demographic data from a Kansas prairie to demonstrate that interannual climate variability promotes the coexistence of three common grass species. Specifically, we show that (i) the dynamics of the three species satisfy all requirements of ‘‘storage effect’’ theory based on recruitment …

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Mansfield Ct: Planning A New Village Center, Maggie Jones, Richard Barringer Aug 2006

Mansfield Ct: Planning A New Village Center, Maggie Jones, Richard Barringer

Planning

The case follows the development of a plan for a new village center in Storrs, the central village of Mansfield, Connecticut. A process that was transparent and inclusive of the community members yielded a plan that gained the approval of the Town, the landowner (the University of Connecticut), and the citizenry. The process relied on the mending of fences, the leadership of key participants, and an innovative strategy that included development of a nonprofit corporation and creative use of grant money. While zoning changes are still in the works, the first stage of building goes forward.

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Some Preservation Techniques For (Deep Water) Coral Samples For Subsequent Molecular Studies: A Special Supplement From Harbor Branch Oceanographic Institute, Jose V. Lopez Aug 2006

Some Preservation Techniques For (Deep Water) Coral Samples For Subsequent Molecular Studies: A Special Supplement From Harbor Branch Oceanographic Institute, Jose V. Lopez

Marine & Environmental Sciences Faculty Reports

Around the time that the thirteen original Atlantic colonies were fighting for independence from Britain, there existed little agreement among naturalists as to the nature of corals. Were they inanimate (stones), plants, animals, or intermediate between the latter two (zoophytes)? This diversity of definition and opinions undoubtedly produced considerable confusion and disagreement among naturalists interested in such things. The symbiotic nature of algal cells in the tissues of some corals was also not well understood. It was not until the Darwinian period in the nineteenth century that little doubt remained, and therefore it was generally agreed, that corals were actually …

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Assembly Of High-Anisotropy L10 Fept Nanocomposite Films, David J. Sellmyer, Yinfan Xu, M. L. Yan, Yucheng Sui, Jian Zhou, Ralph Skomski Aug 2006

Assembly Of High-Anisotropy L10 Fept Nanocomposite Films, David J. Sellmyer, Yinfan Xu, M. L. Yan, Yucheng Sui, Jian Zhou, Ralph Skomski

David Sellmyer Publications

In this paper we report results on the synthesis and magnetic properties of L10 FePt nanocomposite films. Three fabrication methods have been developed to produce high-anisotropy FePt films: non-epitaxial growth of (0 0 1)-oriented FePt:X (X=Ag, C) composite films that might be used for perpendicular media; monodispersed FePt(CFx) core–shell nanocluster-assembled films grown with a gas-aggregation technique and having uniform cluster size and narrow size distribution; and template-mediated self-assembled FePt clusters prepared with chemical synthesis by a hydrogen reduction technique, which has a high potential for controlling both cluster size and orientation. The magnetic properties are controllable through …

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Total Dissociative Electron Attachment Cross Sections For Molecular Constituents Of Dna, Kayvan Aflatooni, A.M. Scheer, Paul Burrow Aug 2006

Total Dissociative Electron Attachment Cross Sections For Molecular Constituents Of Dna, Kayvan Aflatooni, A.M. Scheer, Paul Burrow

Paul Burrow Publications

Total cross sections for the dissociative electron attachment process are presented for the DNA bases thymine, cytosine, and adenine and for three compounds used as surrogates for the ribose and phosphate groups, tetrahydrofuran, 3-hydroxytetrahydrofuran, and trimethylphosphate, respectively. Cross section magnitudes are obtained by observation of positive ion production and normalization to ionization cross sections calculated elsewhere using the binary-encounter-Bethe method. The average cross section of the three bases is 3–10 times smaller than the effective cross section per nucleotide reported for single strand breaks in surface-bound super-coiled DNA. Consequently, damage to the bases alone does not appear to account for …

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Can We Have Superconvergent Gradient Recovery Under Adaptive Meshes?, Haijun Wu, Zhimin Zhang Aug 2006

Can We Have Superconvergent Gradient Recovery Under Adaptive Meshes?, Haijun Wu, Zhimin Zhang

Mathematics Research Reports

We study adaptive finite element methods for elliptic problems with domain corner singularities. Our model problem is the two dimensional Poisson equation. Results of this paper are two folds. First, we prove that there exists an adaptive mesh (gauged by a discrete mesh density function) under which the recovered.gradient by the Polynomial Preserving Recovery (PPR) is superconvergent. Secondly, we demonstrate by numerical examples that an adaptive procedure with a posteriori error estimator based on PPR does produce adaptive meshes satisfy our mesh density assumption, and the recovered gradient by PPR is indeed supercoveregent in the adaptive process.

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Wavelet-Based Functional Mixed Model Analysis: Computational Considerations, Richard C. Herrick, Jeffrey S. Morris Aug 2006

Wavelet-Based Functional Mixed Model Analysis: Computational Considerations, Richard C. Herrick, Jeffrey S. Morris

Jeffrey S. Morris

Wavelet-based Functional Mixed Models is a new Bayesian method extending mixed models to irregular functional data (Morris and Carroll, JRSS-B, 2006). These data sets are typically very large and can quickly run into memory and time constraints unless these issues are carefully dealt with in the software. We reduce runtime by 1.) identifying and optimizing hotspots, 2.) using wavelet compression to do less computation with minimal impact on results, and 3.) dividing the code into multiple executables to be run in parallel using a grid computing resource. We discuss rules of thumb for estimating memory requirements and computation times in …

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Architecture Of Air-Filled Caves Within The Karst Of The Brooksville Ridge, West-Central Florida, Lee J. Florea Aug 2006

Architecture Of Air-Filled Caves Within The Karst Of The Brooksville Ridge, West-Central Florida, Lee J. Florea

Lee J Florea, PhD, P.G.

Air-filled caves surveyed in the Brooksville Ridge of west-central Florida provide insight into the organization of karstic permeability within the unconfined portions of the Upper Floridan Aquifer. The morphology of the passages that compose these caves in geologically young, high-permeability limestones is strikingly different from caves found in ancient carbonates far from the influence of the coast. Cave passages in west-central Florida are laterally extensive and tiered. Principal horizons of cave development occur between +3 m and +5 m, +12 m and +15 m, and +20 m and +22 m above modern sea level. The primary guide of cave passage …

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Bayesian Sample Size Calculations In Phase Ii Clinical Trials Using A Mixture Of Informative Priors., Byron J. Gajewski, Matthew S. Mayo Aug 2006

Bayesian Sample Size Calculations In Phase Ii Clinical Trials Using A Mixture Of Informative Priors., Byron J. Gajewski, Matthew S. Mayo

Byron J Gajewski

A number of researchers have discussed phase II clinical trials from a Bayesian perspective. A recent article by Mayo and Gajewski focuses on sample size calculations, which they determine by specifying an informative prior distribution and then calculating a posterior probability that the true response will exceed a prespecified target. In this article, we extend these sample size calculations to include a mixture of informative prior distributions. The mixture comes from several sources of information. For example consider information from two (or more) clinicians. The first clinician is pessimistic about the drug and the second clinician is optimistic. We tabulate …

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Oxidative Carbonylation And Conjugated Processes With Carbon Monoxide Participation Catalyzed By Palladium Complexes (In Russian), Lev G. Bruk, Irina V. Oshanina, Sergey N. Gorodsky, Oleg N. Temkin Aug 2006

Oxidative Carbonylation And Conjugated Processes With Carbon Monoxide Participation Catalyzed By Palladium Complexes (In Russian), Lev G. Bruk, Irina V. Oshanina, Sergey N. Gorodsky, Oleg N. Temkin

Sergey N. Gorodsky

No abstract provided.

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Nested Markov Compliance Class Model In The Presence Of Time-Varying Noncompliance, Julia Y. Lin, Thomas R. Tenhave, Michael R. Elliott Aug 2006

Nested Markov Compliance Class Model In The Presence Of Time-Varying Noncompliance, Julia Y. Lin, Thomas R. Tenhave, Michael R. Elliott

UPenn Biostatistics Working Papers

We consider a Markov structure for partially unobserved time-varying compliance classes in the Imbens-Rubin (1997) compliance model framework. The context is a longitudinal randomized intervention study where subjects are randomized once at baseline, outcomes and patient adherence are measured at multiple follow-ups, and patient adherence to their randomized treatment could vary over time. We propose a nested latent compliance class model where we use time-invariant subject-specific compliance principal strata to summarize longtudinal trends of subject-specific time-varying compliance patterns. The principal strata are formed using Markov models that related current compliance behavior to compliance history. Treatment effects are estimated as intent-to …

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Generic Nonsinusoidal Phase Error Correction For 3d Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau Aug 2006

Generic Nonsinusoidal Phase Error Correction For 3d Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau

Song Zhang

Structured light system using a digital video projector is increasingly used for a 3-D shape measurement because of its digital nature. However, the nonlinear gamma of the projector causes the projected fringe patterns to be non-sinusoidal, which results in phase error therefore shape measurement error. Previous work showed that, by using a small look-up-table (LUT), this type of phase error can be reduced significantly for a three-step phase-shifting algorithm. In this research, we prove that this type of phase error compensation method is not limited to a three-step phase-shifting algorithm. It is generic for any phase-shifting algorithm. The phase error …

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High-Resolution Real-Time 3d Absolute Coordinates Measurement Using A Fast Three-Step Phase-Shifting Algorithm, Song Zhang, Dale Royer, Shing-Tung Yau Aug 2006

High-Resolution Real-Time 3d Absolute Coordinates Measurement Using A Fast Three-Step Phase-Shifting Algorithm, Song Zhang, Dale Royer, Shing-Tung Yau

Song Zhang

High-resolution, real-time 3-D absolute coordinate measurement is highly important in many fields. This paper presents such a system that measures 3-D absolute geometric shapes and positions at 30 frames per second (fps), with an image resolution of 532 × 500. The system is based on a digital fringe projection and fast three-step phase-shifting method. It utilizes a digital-light-processing (DLP) projector to project color encoded computer generated phase-shifted fringe patterns in grayscale, a high-speed CCD camera synchronized with the projector to capture fringe images at 90 fps. Based on the three-step phase-shifting algorithm, any successive three fringe images can be used …

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Strychninium (S)-2-(2-Bromo­Phen­Oxy)Propanoate 1.4-Hydrate, Kraig A. Wheeler, Aaron M. Lineberry Aug 2006

Strychninium (S)-2-(2-Bromo­Phen­Oxy)Propanoate 1.4-Hydrate, Kraig A. Wheeler, Aaron M. Lineberry

Kraig A. Wheeler

In the title mol­ecular salt, C21H23N2O2+·C9H8BrO3−·1.4H2O, the components are linked by inter­molecular C—O−⋯H—+N and OW—H⋯O inter­actions.

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“Late Cretaceous Terrestrial Vertebrates From Madagascar: Implications For Latin American Biogeography.”, Raymond Rogers, D.W. Krause, P.M. O’Connor, K. Curry Rogers, S.D. Sampson, G.A. Buckley Aug 2006

“Late Cretaceous Terrestrial Vertebrates From Madagascar: Implications For Latin American Biogeography.”, Raymond Rogers, D.W. Krause, P.M. O’Connor, K. Curry Rogers, S.D. Sampson, G.A. Buckley

Raymond Rogers

No abstract provided.

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Whole Earth Telescope Observations Of The Pulsating Subdwarf B Star Pg 0014+067, Maja Vučković, Matt A. Wood, V. Wilkat Aug 2006

Whole Earth Telescope Observations Of The Pulsating Subdwarf B Star Pg 0014+067, Maja Vučković, Matt A. Wood, V. Wilkat

Aerospace, Physics, and Space Science Faculty Publications

PG 0014+067 is one of the most promising pulsating subdwarf B stars for seismic analysis, as it has a rich pulsation spectrum. The richness of its pulsations, however, poses a fundamental challenge to understanding the pulsations of these stars, as the mode density is too complex to be explained only with radial and nonradial low-degree (l < 3) p-modes without rotational splittings. One proposed solution, suggested by Brassard et al. in 2001 for the case of PG 0014+067 in particular, assigns some modes with high degree (l - 3). On the other hand, theoretical models of sdB stars suggest that they may retain rapidly rotating cores, and so the high mode density may result from the presence of a few rotationally split triplet (l = 1) and quintuplet (l = 2) modes, along with radial (l = 0)p-modes. To examine alternative theoretical models for these stars, we need better frequency resolution and denser longitude coverage. Therefore, we observed this star with the Whole Earth Telescope for two weeks in 2004 October. In this paper we report the results of Whole Earth Telescope observations of the pulsating subdwarf B star PG 0014+067. We find that the frequencies seen in PG 0014+067 do not appear to fit any theoretical model currently available; however, we find a simple empirical relation that is able to match all of the well-determined frequencies in this star.

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Nash Equilibria In Cauchy-Random Zero-Sum And Coordination Matrix Games, David P. Roberts Aug 2006

Nash Equilibria In Cauchy-Random Zero-Sum And Coordination Matrix Games, David P. Roberts

Mathematics Publications

We consider zero-sum games (A, − A) and coordination games (A,A), where A is an m-by-n matrix with entries chosen independently with respect to the Cauchy distribution. In each case, we give an exact formula for the expected number of Nash equilibria with a given support size and payoffs in a given range, and also asymptotic simplications for matrices of a fixed shape and increasing size. We carefully compare our results with recent results of McLennan and Berg on Gaussian random bimatrix games (A,B), and describe how …

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South Kingstown Ri: New Zoning For An Historic Mill, Maggie Jones, Richard Barringer Aug 2006

South Kingstown Ri: New Zoning For An Historic Mill, Maggie Jones, Richard Barringer

Planning

The village of Peace Dale in the town of South Kingstown, Rhode Island, developed around several mills that commenced operations in the 1800s. One mill, known as the Palisades, is still partially active and in excellent condition, but much of its square footage is unutilized. A citizens’ group of artists and business people joined with the mill owners and the town of South Kingstown to develop new zoning regulations to make more flexible the permitted uses for the mill site. The proposed zoning will allow the mill complex to feature a mix of retail, residential, and manufacturing uses, while preserving …

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Augusta Me: The New Bridge Begets A New Planned Neighborhood, Molly Pulsifer, Richard Barringer Aug 2006

Augusta Me: The New Bridge Begets A New Planned Neighborhood, Molly Pulsifer, Richard Barringer

Planning

Construction of a new Third Bridge over the Kennebec River in Augusta offered the prospect of a new and handsome gateway to the city. Further, the resulting change in traffic patterns offered the City the chance to plan for a pattern of development quite different from what the city had experienced for the past half-century. The case study describes the planning and construction of the new bridge and corridors that re-routed traffic out of Augusta’s downtown and older neighborhoods, and created the opportunity for planned development adjacent to the corridor created by the new bridge. It goes on to describe …

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Research On Synthetic Rope And Its Future In Timber Harvesting, Joel N. Hartter, Jared Leonard, John Garland, Steve Pilkerton Aug 2006

Research On Synthetic Rope And Its Future In Timber Harvesting, Joel N. Hartter, Jared Leonard, John Garland, Steve Pilkerton

Geography

Steel wire rope is used for many logging applications. It has served the industry well in terms of strength, durability, and longevity. However, steel wire rope is difficult to use because it is stiff, heavy, and unyielding. These characteristics can lead to fatigue and exhaustion, and may contribute to worker injuries. Ultra-high molecular weight polyethylene synthetic rope has the potential to replace steel wire rope for selected logging applications. Research shows ergonomic gains and other operational effectiveness with its use. This paper presents research results, potentials, and issues in improving economic and ergonomic performance of ground-based and cable logging. Potential …

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Incentive Awards To Class Action Plaintiffs: An Empirical Study, Theodore Eisenberg, Geoffrey P. Miller Aug 2006

Incentive Awards To Class Action Plaintiffs: An Empirical Study, Theodore Eisenberg, Geoffrey P. Miller

Cornell Law Faculty Publications

Incentive awards to representative plaintiffs in class actions have been the focus of recent law reform efforts and have generated inconsistent case law. But little is known about such awards. This study of 374 opinions from 1993 to 2002 finds that awards were granted in about 28 percent of settled class actions. The rate of awards varied by case category as follows: consumer credit actions 59 percent, employment discrimination cases 46 percent, antitrust cases 35 percent, securities cases 24 percent (before the Private Securities Litigation Reform Act of 1995 limited awards), and corporate and mass tort actions less than 10 …

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Ultra-Wideband Technology For Video Surveillance Sensor Networks, Xiaojing Huang, Eryk Dutkiewicz, Ricardo Gandia, Darryn Lowe Aug 2006

Ultra-Wideband Technology For Video Surveillance Sensor Networks, Xiaojing Huang, Eryk Dutkiewicz, Ricardo Gandia, Darryn Lowe

Faculty of Informatics - Papers (Archive)

Wireless sensor networks have received a lot of attention in recent years both in the research community and in standards organizations. The emphasis of most sensor network research activities has been on the development of low cost and low power technologies for low bit rate applications. In this paper, we describe our work on ultra-wideband (UWB) sensor network technology targeted for video surveillance applications that require high immunity to noise, interference and jamming, high bit rate, and quality of service support. Such sensor networks are expected to find primary applications in the public safety and military fields. Our emphasis in …

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Strike One- You're Out! Aug 2006

Strike One- You're Out!

Other Bird Strike and Aviation Materials

Wildlife management and habitat modification at airports can help eliminate or greatly reduce collisions between aircraft and birds or other wildlife. This leaflet provides the aviation community with information on how the Federal Government can help with these life-threatening problems.

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Major Land Resource Areas Of Montana, Natural Resources Conservation Service Aug 2006

Major Land Resource Areas Of Montana, Natural Resources Conservation Service

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Major Land Resource Areas 32, Northern Intermountain Desertic Basins 43A, Northern Rocky Mountains 43B, Central Rocky Mountains 44A, Northern Rocky Mountain Valleys 44B, Central Rocky Mountain Valleys 46, Northern Rocky Mountain Foothills 52, Brown Glaciated Plains 53A, Northern Dark Brown Glaciated Plains 54, Soft Shale Plains 58A, Northern Rolling Plains, Northern Part 58B, Northern Rolling Plains, Southern Part 58C, Northern Rolling Plains, Northeastern Part 58D, Northern Rolling Plains, Eastern Part 60A, Pierre Shale Plains and Badlands 60B, Pierre Shale Plains and Badlands, Northern Part

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Uptake Of Spartina-Derived Humic Nitrogen By Estuarine Phytoplankton In Nonaxenic And Axenic Culture, Jh See, Da Bronk, Aj Lewitus Aug 2006

Uptake Of Spartina-Derived Humic Nitrogen By Estuarine Phytoplankton In Nonaxenic And Axenic Culture, Jh See, Da Bronk, Aj Lewitus

VIMS Articles

Humic substances are a collection of colored organic acids characterized by high molecular weight and low nitrogen (N) content that are thought to be biologically recalcitrant. We examined a suite of nonaxenic estuarine phytoplankton isolates to determine their ability to take up N-15-labeled humic substances formed in the laboratory and supplied as the sole N source. All 17 estuarine and coastal strains took up the added humic N, but the one polar isolate did not. Two of the coastal isolates (Heterosigma akashiwo and Fibrocapsa japonica) could take up the humic N in nonaxenic culture but not in axenic culture, suggesting …

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