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Full-Text Articles in Life Sciences

Monitoring Old Growth In Frequent-Fire Landscapes, Carl E. Fiedler, Peter Friederici, Mark Petruncio Dec 2007

Monitoring Old Growth In Frequent-Fire Landscapes, Carl E. Fiedler, Peter Friederici, Mark Petruncio

Forest Management Faculty Publications

In this article, we discuss how to monitor the structural and functional attributes of old growth, as well as its associated plant communities and wildlife, both to determine the possible need for treatment and to assess post-treatment progress toward desired conditions. Monitoring can be used to detect conditions (or agents) that threaten existing old growth and also to document indicators of healthy, functioning old-growth systems.


Managing For Old Growth In Frequent-Fire Landscapes, Carl E. Fiedler, Peter Friederici, Mark Petruncio, Charles Denton, W. David Hacker Dec 2007

Managing For Old Growth In Frequent-Fire Landscapes, Carl E. Fiedler, Peter Friederici, Mark Petruncio, Charles Denton, W. David Hacker

Forest Management Faculty Publications

There is no one-size-fits-all approach to managing frequent-fire, old-growth forests. However, there are general guidelines to follow: 1) set objectives for both structure (tree density, diameter distribution, tree species composition, spatial arrangement, amount of coarse woody debris) and function (nutrient cycling, desired tree species regeneration); 2) prioritize treatments according to ecological, economic, and social needs and risks; 3) identify the potential treatments (natural fire, prescribed fire, silvicultural cutting) that best meet the objectives and scale of the project; and 4) implement the treatment (s). We discuss each of these guidelines in this article.


A Novel Zinc-Binding Domain Is Essential For Formation Of The Functional Junin Virus Envelope Glycoprotein Complex, Joanne York, Jack H. Nunberg Dec 2007

A Novel Zinc-Binding Domain Is Essential For Formation Of The Functional Junin Virus Envelope Glycoprotein Complex, Joanne York, Jack H. Nunberg

Biological Sciences Faculty Publications

The envelope glycoprotein of the Junin arenavirus (GP-C) mediates entry into target cells through a pH-dependent membrane fusion mechanism. Unlike other class I viral fusion proteins, the mature GP-C complex retains a cleaved, 58-amino-acid signal peptide (SSP) as an essential subunit, required both for trafficking of GP-C to the cell surface and for the activation of membrane fusion. SSP has been shown to associate noncovalently in GP-C via the cytoplasmic domain (CTD) of the transmembrane fusion subunit G2. In this report we investigate the molecular basis for this intersubunit interaction. We identify an invariant series of six cysteine and histidine …


The Tropical Forest And Fire Emissions Experiment: Method Evaluation Of Volatile Organic Compound Emissions Measured By Ptr-Ms, Ftir, And Gc From Tropical Biomass Burning, T. G. Karl, Ted J. Christian, Robert J. Yokelson, Paulo Artaxo, Wei Min Hao, Alex Guenther Nov 2007

The Tropical Forest And Fire Emissions Experiment: Method Evaluation Of Volatile Organic Compound Emissions Measured By Ptr-Ms, Ftir, And Gc From Tropical Biomass Burning, T. G. Karl, Ted J. Christian, Robert J. Yokelson, Paulo Artaxo, Wei Min Hao, Alex Guenther

Chemistry and Biochemistry Faculty Publications

Volatile Organic Compound (VOC) emissions from fires in tropical forest fuels were quantified using Proton-Transfer-Reaction Mass Spectrometry (PTRMS), Fourier Transform Infrared Spectroscopy (FTIR) and gas chromatography (GC) coupled to PTRMS (GC-PTR-MS). We investigated VOC emissions from 19 controlled laboratory fires at the USFS (United States Forest Service) Fire Sciences Laboratory and 16 fires during an intensive airborne field campaign during the peak of the burning season in Brazil in 2004. The VOC emissions were dominated by oxygenated VOCs (OVOC) (OVOC/NMHC similar to 4:1, NMHC: non-methane hydrocarbons) The specificity of the PTR-MS instrument, which measures the mass to charge ratio of …


Structural Biology: A Receptor Unlocked, Stephen R. Sprang Nov 2007

Structural Biology: A Receptor Unlocked, Stephen R. Sprang

Biological Sciences Faculty Publications

No abstract provided.


Additive And Synergistic Bactericidal Activity Of Antibodies Directed Against Minor Outer Membrane Proteins Of Neisseria Meningitidis, Vincent E. Weynants, Christiane M. Feron, Karine K. Goraj, Martine P. Bos, Philippe A. Denoeal, Vincent G. Verlant, Jan Tommassen, Ian R. A. Peak, Ralph C. Judd, Michael P. Jennings, Jan T. Poolman Nov 2007

Additive And Synergistic Bactericidal Activity Of Antibodies Directed Against Minor Outer Membrane Proteins Of Neisseria Meningitidis, Vincent E. Weynants, Christiane M. Feron, Karine K. Goraj, Martine P. Bos, Philippe A. Denoeal, Vincent G. Verlant, Jan Tommassen, Ian R. A. Peak, Ralph C. Judd, Michael P. Jennings, Jan T. Poolman

Biological Sciences Faculty Publications

Neisseria meningitidis serogroup B is a major cause of bacterial meningitis in younger populations. The available vaccines are based on outer membrane vesicles obtained from wild-type strains. In children less than 2 years old they confer protection only against strains expressing homologous PorA, a major, variable outer membrane protein (OMP). We genetically modified a strain in order to eliminate PorA and to overproduce one or several minor and conserved OMPs. Using a mouse model mimicking children's PorA-specific bactericidal activity, it was demonstrated that overproduction of more than one minor OMP is required to elicit antibodies able to induce complement-mediated killing …


Native Plant Diversity Resists Invasion At Both Low And High Resource Levels, John L. Maron, Marilyn Marler Oct 2007

Native Plant Diversity Resists Invasion At Both Low And High Resource Levels, John L. Maron, Marilyn Marler

Biological Sciences Faculty Publications

Human modification of the environment is causing both loss of species and changes in resource availability. While studies have examined how species loss at the local level can influence invasion resistance, interactions between species loss and other components of environmental change remain poorly studied. In particular, the manner in which native diversity interacts with resource availability to influence invasion resistance is not well understood. We created experimental plant assemblages that varied in native species (1–16 species) and/or functional richness (defined by rooting morphology and phenology; one to five functional groups). We crossed these diversity treatments with resource (water) addition to …


The Tropical Forest And Fire Emissions Experiment: Trace Gases Emitted By Smoldering Logs And Dung From Deforestation And Pasture Fires In Brazil, Ted J. Christian, Robert J. Yokelson, João A. Carvalho, David W.T. Griffith, Ernesto C. Alvarado, José Carlos Santos, Turibio Gomes Soares Neto, Carlos A.Gurgel Veras, Wei Min Hao Sep 2007

The Tropical Forest And Fire Emissions Experiment: Trace Gases Emitted By Smoldering Logs And Dung From Deforestation And Pasture Fires In Brazil, Ted J. Christian, Robert J. Yokelson, João A. Carvalho, David W.T. Griffith, Ernesto C. Alvarado, José Carlos Santos, Turibio Gomes Soares Neto, Carlos A.Gurgel Veras, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

Earlier work showed that Amazonian biomass burning produces both lofted and initially unlofted emissions in large amounts. A mobile, Fourier transform infrared spectrometer (FTIR) measured the unlofted emissions of 17 trace gases from residual smoldering combustion (RSC) of logs as part of the Tropical Forest and Fire Emissions Experiment (TROFFEE) during the 2004 Amazonian dry season. The RSC emissions were highly variable and the few earlier RSC measurements lay near the high end of combustion efficiency observed in this study. Fuel consumption by RSC was ∼5% of total for a planned deforestation fire. Much regional RSC probably occurs in the …


The Tropical Forest And Fire Emissions Experiment: Emission, Chemistry, And Transport Of Biogenic Volatile Organic Compounds In The Lower Atmosphere Over Amazonia, Thomas Karl, Alex Guenther, Robert J. Yokelson, Jim Greenberg, Mark Potosnak, Donald R. Blake, Paulo Artaxo Sep 2007

The Tropical Forest And Fire Emissions Experiment: Emission, Chemistry, And Transport Of Biogenic Volatile Organic Compounds In The Lower Atmosphere Over Amazonia, Thomas Karl, Alex Guenther, Robert J. Yokelson, Jim Greenberg, Mark Potosnak, Donald R. Blake, Paulo Artaxo

Chemistry and Biochemistry Faculty Publications

Airborne and ground-based mixing ratio and flux measurements using eddy covariance (EC) and for the first time the mixed layer gradient (MLG) and mixed layer variance (MLV) techniques are used to assess the impact of isoprene and monoterpene emissions on atmospheric chemistry in the Amazon basin. Average noon isoprene (7.8 +/- 2.3 mg/m(2)/h) and monoterpene fluxes (1.2 +/- 0.5 mg/m(2)/h)compared well between ground and airborne measurements and are higher than fluxes estimated in this region during other seasons. The biogenic emission model, Model of Emissions of Gases and Aerosols from Nature (MEGAN), estimates fluxes that are within the model and …


Transcriptional Regulation Of The Heme Binding Protein Gene Family Of Bartonella Quintana Is Accomplished By A Novel Promoter Element And Iron Response Regulator, James M. Battisti, Laura S. Smitherman, Kate N. Sappington, Nermi L. Parrow, Rahul Raghavan, Michael F. Minnick Sep 2007

Transcriptional Regulation Of The Heme Binding Protein Gene Family Of Bartonella Quintana Is Accomplished By A Novel Promoter Element And Iron Response Regulator, James M. Battisti, Laura S. Smitherman, Kate N. Sappington, Nermi L. Parrow, Rahul Raghavan, Michael F. Minnick

Biological Sciences Faculty Publications

We previously identified a five-member family of hemin-binding proteins (Hbp's) of Bartonella quintana that bind hemin on the outer surface but share no homology with known bacterial heme receptors. Subsequently, we demonstrated that expression of the hbp family is significantly influenced by oxygen, heme, and temperature conditions encountered by the pathogen in the human host and the body louse vector; e.g., we observed a dramatic (>100-fold) increase in hbpC transcript levels in response to the "louse-like" temperature of 30 degrees C. The goal of the present study was to identify a transcription factor(s) involved in the coordinated and differential …


The Unusual 23s Rrna Gene Of Coxiella Burnetii: Two Self-Splicing Group I Introns Flank A 34-Base-Pair Exon, And One Element Lacks The Canonical Omega G, Rahul Raghavan, Scott R. Miller, Linda D. Hicks, Michael F. Minnick Sep 2007

The Unusual 23s Rrna Gene Of Coxiella Burnetii: Two Self-Splicing Group I Introns Flank A 34-Base-Pair Exon, And One Element Lacks The Canonical Omega G, Rahul Raghavan, Scott R. Miller, Linda D. Hicks, Michael F. Minnick

Biological Sciences Faculty Publications

We describe the presence and characteristics of two self-splicing group I introns in the sole 23S rRNA gene of Coxiella burnetii. The two group I introns, Cbu.L1917 and Cbu.L1951, are inserted at sites 1917 and 1951 (Escherichia coli numbering), respectively, in the 23S rRNA gene of C. bumetii. Both introns were found to be self-splicing in vivo and in vitro even though the terminal nucleotide of Cbu.L1917 is adenine and not the canonical conserved guanine, termed Omega G, found in Cbu.L1951 and all other group I introns described to date. Predicted secondary structures for both introns were constructed and revealed …


Reproductive Biology Of The Violet-Chested Hummingbird In Venezuela And Comparisons With Other Tropical And Temperate Hummingbirds, Karolina Fierro-Calderon, Thomas E. Martin Aug 2007

Reproductive Biology Of The Violet-Chested Hummingbird In Venezuela And Comparisons With Other Tropical And Temperate Hummingbirds, Karolina Fierro-Calderon, Thomas E. Martin

Wildlife Biology Faculty Publications

We provide details on the breeding biology of the Violet-chested Hummingbird (Sternoclyta cyanopectus) based on 67 nests studied in Yacambu National Park, Venezuela, from 2002 through 2006. Clutch size was two white eggs, usually laid every other day. Fresh egg mass (0.95 +/- 0.14 g) was 15% of female mass. Incubation and nestling periods were 20.4 +/- 0.3 and 26.0 +/- 0.4 days, respectively. Nest attentiveness increased from 60% in early incubation to 68% in late incubation. The female spent 50% of her time brooding young nestlings, but ceased brooding by 13 days of age. Only the female fed the …


Selection For Rapid Embryo Development Correlates With Embryo Exposure To Maternal Androgens Among Passerine Birds, Hubert Schwabl, Maria G. Palacios, Thomas E. Martin Aug 2007

Selection For Rapid Embryo Development Correlates With Embryo Exposure To Maternal Androgens Among Passerine Birds, Hubert Schwabl, Maria G. Palacios, Thomas E. Martin

Wildlife Biology Faculty Publications

Greater offspring predation favors evolution of faster development among species. We hypothesized that greater offspring predation exerts selection on mothers to increase levels of anabolic androgens in egg yolks to achieve faster development. Here, we tested whether (1) concentrations of yolk androgens in passerine species were associated with offspring predation and (2) embryo and nestling development rates were associated with yolk androgen concentrations. We examined three androgens that increase in potency along the synthesis pathway: androstenedione (A(4)) to testosterone (T) to 5 alpha-dihydrotestosterone (5 alpha-DHT). Concentrations of none of these steroids were related to clutch size; only A, was allometrically …


Phylogeography Of The Thermophilic Cyanobacterium Mastigocladus Laminosus, Scott R. Miller, Richard W. Castenholz, Deana Pedersen Aug 2007

Phylogeography Of The Thermophilic Cyanobacterium Mastigocladus Laminosus, Scott R. Miller, Richard W. Castenholz, Deana Pedersen

Biological Sciences Faculty Publications

We have taken a phylogeographic approach to investigate the demographic and evolutionary processes that have shaped the geographic patterns of genetic diversity for a sample of isolates of the cosmopolitan thermophillic cyanobacterial Mastigocladus laminosus morphotype collected from throughout most of its range. Although M. laminosus is found in thermal areas throughout the world, our observation that populations are typically genetically differentiated on local geographic scales suggests the existence of dispersal barriers, a conclusion corroborated by evidence for genetic isolation by distance. Genealogies inferred using nitrogen metabolism gene sequence data suggest that a significant amount of the extant global diversity of …


High Rates Of Sulfate Reduction In A Low-Sulfate Hot Spring Microbial Mat Are Driven By A Low Level Of Diversity Of Sulfate-Respiring Microorganisms, Jesse G. Dillon, Susan Fishbain, Scott R. Miller, Brad M. Bebout, Kristen S. Habicht, Samuel M. Webb, David A. Stahl Aug 2007

High Rates Of Sulfate Reduction In A Low-Sulfate Hot Spring Microbial Mat Are Driven By A Low Level Of Diversity Of Sulfate-Respiring Microorganisms, Jesse G. Dillon, Susan Fishbain, Scott R. Miller, Brad M. Bebout, Kristen S. Habicht, Samuel M. Webb, David A. Stahl

Biological Sciences Faculty Publications

The importance of sulfate respiration in the microbial mat found in the low-sulfate thermal outflow of Mushroom Spring in Yellowstone National Park was evaluated using a combination of molecular, microelectrode, and radiotracer studies. Despite very low sulfate concentrations, this mat community was shown to sustain a highly active sulfur cycle. The highest rates of sulfate respiration were measured close to the surface of the mat late in the day when photosynthetic oxygen production ceased and were associated with a Thermodesuffiovibrio-like population. Reduced activity at greater depths was correlated with novel populations of sulfate-reducing microorganisms, unrelated to characterized species, and most …


Hiv-2 Rna Dimerization Is Regulated By Intramolecular Interactions In Vitro, Tayyba T. Baig, Jean-Marc Lanchy, J. Stephen Lodmell Aug 2007

Hiv-2 Rna Dimerization Is Regulated By Intramolecular Interactions In Vitro, Tayyba T. Baig, Jean-Marc Lanchy, J. Stephen Lodmell

Biological Sciences Faculty Publications

Genomic RNA dimerization is an essential process in the retroviral replication cycle. In vitro, HIV-2 RNA dimerization is mediated at least in part by direct intermolecular interaction at stem-loop 1 (SL1) within the 5'-untranslated leader region (UTR). RNA dimerization is thought to be regulated via alternate presentation and sequestration of dimerization signals by intramolecular base- pairings. One of the proposed regulatory elements is a palindrome sequence ( pal) located upstream of SL1. To investigate the role of pal in the regulation of HIV-2 dimerization, we randomized this motif and selected in vitro for dimerization- competent and dimerization-impaired RNAs. Energy minimization …


Analysis Of Flow Competence In An Alluvial Gravel Bed Stream, Dupuyer Creek, Montana, Andrew C. Whitaker, Donald F. Potts Jul 2007

Analysis Of Flow Competence In An Alluvial Gravel Bed Stream, Dupuyer Creek, Montana, Andrew C. Whitaker, Donald F. Potts

Forest Management Faculty Publications

Critical shear stress and unit discharge flow competence models were tested against coarse bed load data from Dupuyer Creek, Montana, United States. Maximum particle sizes sampled (Dmax) and D-50 to D-90 percentiles in the bed load grain size distribution were well correlated with both shear stress and unit discharge. Bed load grain sizes became coarser with increasing flow strength. For the D-max curve, Shields dimensionless parameter for the surface D-50 was estimated at 0.044, and the exponent for relative particle size (D-i/ D-50) was - 0.59. In the unit discharge criterion the critical flow to entrain the surface D50 was …


Microwave Absorption Of Patterned Arrays Of Nanosized Magnetic Stripes With Different Aspect Ratios, Leszek M. Malkinski, Minghui Yu, Andriy Vovk, Donald J. Scherer Ii, Leonard Spinu, Weilie Zhou, Scott L. Whittenburg, Zachary Davis, Jin-Seung Jung May 2007

Microwave Absorption Of Patterned Arrays Of Nanosized Magnetic Stripes With Different Aspect Ratios, Leszek M. Malkinski, Minghui Yu, Andriy Vovk, Donald J. Scherer Ii, Leonard Spinu, Weilie Zhou, Scott L. Whittenburg, Zachary Davis, Jin-Seung Jung

Chemistry and Biochemistry Faculty Publications

Arrays consisting of nanosized stripes of Permalloy with different length-to-width ratios have been fabricated using electron beam nanolithography, magnetron sputtering, and lift-off process. These stripes have a thickness of , a width of , and different lengths ranging from . The stripes are separated by a distance of . Magnetization hysteresis loops were measured using a superconducting quantum interference device susceptometer. Microwave absorption at was determined by means of ferromagnetic resonance technique. The dependence of the resonant field on the angle between the nanostructure and the in-plane dc magnetic field indicates the presence of uniaxial magnetic anisotropy associated with the …


Breeding Biology Of Passerines In A Subtropical Montane Forest In Northwestern Argentina, Sonya K. Auer, Ronald D. Bassar, Joseph J. Fontaine, Thomas E. Martin May 2007

Breeding Biology Of Passerines In A Subtropical Montane Forest In Northwestern Argentina, Sonya K. Auer, Ronald D. Bassar, Joseph J. Fontaine, Thomas E. Martin

Wildlife Biology Faculty Publications

The breeding ecology of south temperate bird species is less widely known than that of north temperate species, yet because they comprise a large portion of the world's avian diversity, knowledge of their breeding ecology can contribute to a more comprehensive understanding of the geographic diversity of avian reproductive traits and life history strategies. We provide the first detailed examination of the reproductive strategies of 18 forest passerines of subtropical, northwestern Argentina. Mean clutch sizes were smaller and egg mass was greater than for north temperate birds, but differed among species and nest types, with cavity-nesters having larger clutches than …


Electronic Anisotropy Between Open Shell Atoms In First And Second Order Perturbation Theory, Gerrit C. Groenenboom, Xi Chu, R. Krems May 2007

Electronic Anisotropy Between Open Shell Atoms In First And Second Order Perturbation Theory, Gerrit C. Groenenboom, Xi Chu, R. Krems

Chemistry and Biochemistry Faculty Publications

The interaction between two atoms in states with nonzero electronic orbital angular momenta is anisotropic and can be represented by a spherical tensor expansion. The authors derive expressions for the first order (electrostatic) and second order (dispersion and induction) anisotropic interaction coefficients in terms of the multipole moments and dynamic polarizabilities of the atoms and show that a complete description of the second order interaction requires odd rank or "out-of-phase" polarizabilities. The authors relate the tensorial expansion coefficients to the adiabatic Born-Oppenheimer potentials of the molecule and show that there are linear, and in some cases nonlinear, constraints on the …


Proteomic And Immunoblot Analyses Of Bartonella Quintana Total Membrane Proteins Identify Antigens Recognized By Sera From Infected Patients, Jenni K. Boonjakuakul, Helen L. Gerns, Yu-Ting Chen, Linda D. Hicks, Michael F. Minnick, Scott E. Dixon, Steven C. Hall, Jane E. Koehler May 2007

Proteomic And Immunoblot Analyses Of Bartonella Quintana Total Membrane Proteins Identify Antigens Recognized By Sera From Infected Patients, Jenni K. Boonjakuakul, Helen L. Gerns, Yu-Ting Chen, Linda D. Hicks, Michael F. Minnick, Scott E. Dixon, Steven C. Hall, Jane E. Koehler

Biological Sciences Faculty Publications

Bartonella quintana is a fastidious, gram-negative, rod-shaped bacterium that causes prolonged bacteremia in immunocompetent humans and severe infections in immunocompromised individuals. We sought to define the outer membrane subproteome of B. quintana in order to obtain insight into the biology and pathogenesis of this emerging pathogen and to identify the predominant B. quintana antigens targeted by the human immune system during infection. We isolated the total membrane proteins of B. quintana and identified 60 proteins by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and peptide mass fingerprinting. Using the newly constructed proteome map, we then utilized two-dimensional immunoblotting with sera from …


An Extended Stem-Loop 1 Is Necessary For Human Immunodeficiency Virus Type 2 Replication And Affects Genomic Rna Encapsidation, Jean-Marc Lanchy, J. Stephen Lodmell Apr 2007

An Extended Stem-Loop 1 Is Necessary For Human Immunodeficiency Virus Type 2 Replication And Affects Genomic Rna Encapsidation, Jean-Marc Lanchy, J. Stephen Lodmell

Biological Sciences Faculty Publications

Genomic RNA encapsidation in lentiviruses is a highly selective and regulated process. The unspliced RNA molecules are selected for encapsidation from a pool of many different viral and cellular RNA species. Moreover, two molecules are encapsidated per viral particle, where they are found associated as a dimer. In this study, we demonstrate that a 10-nucleotide palindromic sequence (pal) located at the 3' end of the psi encapsidation signal is critical for human immunodeficiency virus type 2 (HIV-2) replication and affects genomic RNA encapsidation. We used short-term and long-term culture of pal-mutated viruses in permissive C8166 cells and their phenotypic reversion …


Bitopic Membrane Topology Of The Stable Signal Peptide In The Tripartite Junin Virus Gp-C Envelope Glycoprotein Complex, Sudhakar S. Agnihothram, Joanne York, Meg Trahey, Jack H. Nunberg Apr 2007

Bitopic Membrane Topology Of The Stable Signal Peptide In The Tripartite Junin Virus Gp-C Envelope Glycoprotein Complex, Sudhakar S. Agnihothram, Joanne York, Meg Trahey, Jack H. Nunberg

Biological Sciences Faculty Publications

The stable signal peptide (SSP) of the GP-C envelope glycoprotein of the Junin arenavirus plays a critical role in trafficking of the GP-C complex to the cell surface and in its membrane fusion activity. SSP therefore may function on both sides of the lipid membrane. In this study, we have investigated the membrane topology of SSP by confocal microscopy of cells treated with the detergent digitonin to selectively permeabilize the plasma membrane. By using an affinity tag to mark the termini of SSP in the properly assembled GP-C complex, we find that both the N and C termini reside in …


Filling Key Gaps In Population And Community Ecology, Anurag A. Agrawal, David D. Ackerly, Fred Adler, A. Elizabeth Arnold, Carla Cáceres, Daniel F. Doak, Eric Post, Peter J. Hudson, John L. Maron, Kailen A. Mooney, Mary Power, Doug Schemske, Jay Stachowicz, Sharon Strauss, Monica G. Turner, Earl Werner Apr 2007

Filling Key Gaps In Population And Community Ecology, Anurag A. Agrawal, David D. Ackerly, Fred Adler, A. Elizabeth Arnold, Carla Cáceres, Daniel F. Doak, Eric Post, Peter J. Hudson, John L. Maron, Kailen A. Mooney, Mary Power, Doug Schemske, Jay Stachowicz, Sharon Strauss, Monica G. Turner, Earl Werner

Biological Sciences Faculty Publications

We propose research to fill key gaps in the areas of population and community ecology, based on a National Science Foundation workshop identifying funding priorities for the next 5–10 years. Our vision for the near future of ecology focuses on three core areas: predicting the strength and context-dependence of species interactions across multiple scales; identifying the importance of feedbacks from individual interactions to ecosystem dynamics; and linking pattern with process to understand species coexistence. We outline a combination of theory development and explicit, realistic tests of hypotheses needed to advance population and community ecology.


Direct And Interactive Effects Of Enemies And Mutualists On Plant Performance: A Meta-Analysis, William F. Morris, Ruth A. Hufbauer, Anurag A. Agrawal, James D. Bever, Victoria A. Borowicz, Gregory S. Gilbert, John L. Maron, Charles E. Mitchell, Ingrid M. Parker, Alison G. Power, Mark E. Torchin, Diego P. Vázquez Apr 2007

Direct And Interactive Effects Of Enemies And Mutualists On Plant Performance: A Meta-Analysis, William F. Morris, Ruth A. Hufbauer, Anurag A. Agrawal, James D. Bever, Victoria A. Borowicz, Gregory S. Gilbert, John L. Maron, Charles E. Mitchell, Ingrid M. Parker, Alison G. Power, Mark E. Torchin, Diego P. Vázquez

Biological Sciences Faculty Publications

Plants engage in multiple, simultaneous interactions with other species; some (enemies) reduce and others (mutualists) enhance plant performance. Moreover, effects of different species may not be independent of one another; for example, enemies may compete, reducing their negative impact on a plant. The magnitudes of positive and negative effects, as well as the frequency of interactive effects and whether they tend to enhance or depress plant performance, have never been comprehensively assessed across the many published studies on plant–enemy and plant–mutualist interactions. We performed a meta-analysis of experiments in which two enemies, two mutualists, or an enemy and a mutualist …


Climate, Hydrologic Disturbance, And Succession: Drivers Of Floodplain Pattern, Diane C. Whited, Mark S. Lorang, Mary J. Harner, F. Richard Hauer, John S. Kimball, Jack Arthur Stanford Apr 2007

Climate, Hydrologic Disturbance, And Succession: Drivers Of Floodplain Pattern, Diane C. Whited, Mark S. Lorang, Mary J. Harner, F. Richard Hauer, John S. Kimball, Jack Arthur Stanford

Biological Sciences Faculty Publications

Floodplains are among the world's most threatened ecosystems due to the pervasiveness of dams, levee systems, and other modi. cations to rivers. Few unaltered floodplains remain where we may examine their dynamics over decadal time scales. Our study provides a detailed examination of landscape change over a 60-year period ( 1945 - 2004) on the Nyack floodplain of the Middle Fork of the Flathead River, a free-flowing, gravel-bed river in northwest Montana, USA. We used historical aerial photographs and airborne and satellite imagery to delineate habitats ( i.e., mature forest, regenerative forest, water, cobble) within the. oodplain. We related changes …


Size Dependence Of Static And Dynamic Magnetic Properties In Nanoscale Square Permalloy Antidot Arrays, Minghui Yu, Leszek M. Malkinski, Leonard Spinu, Weilie Zhou, Scott L. Whittenburg Mar 2007

Size Dependence Of Static And Dynamic Magnetic Properties In Nanoscale Square Permalloy Antidot Arrays, Minghui Yu, Leszek M. Malkinski, Leonard Spinu, Weilie Zhou, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

Permalloy antidot arrays with different square hole sizes ( , , and ) have been fabricated by means of electron-beam lithography and lift-off techniques. The smaller square hole size results in enhanced remanence and reduced coercivity in the antidot array. Multiple resonance modes were clearly observed for the magnetic field applied normal to the array plane, and double uniform resonance modes occurred when the field deviated more than 30° from the normal to the plane. Two distinct dipolar field patterns with different orientations and magnitudes split the uniform resonance into double resonance modes. The double resonance modes show uniaxial in-plane …


Dynamic Polarizabilities Of Rare-Earth-Metal Atoms And Dispersion Coefficients For Their Interaction With Helium Atoms, Xi Chu, Alexander Dalgarno, Gerrit C. Groenenboom Mar 2007

Dynamic Polarizabilities Of Rare-Earth-Metal Atoms And Dispersion Coefficients For Their Interaction With Helium Atoms, Xi Chu, Alexander Dalgarno, Gerrit C. Groenenboom

Chemistry and Biochemistry Faculty Publications

The dynamic scalar and tensor polarizabilities of the rare-earth-metal atoms are calculated with time-dependent density functional theory. The frequency-dependent polarizabilities at imaginary frequencies are used to determine the isotropic and orientation-dependent van der Waals coefficients for the interactions of the rare-earth-metal atoms with helium atoms. The static polarizabilities are compared with other theoretical values and with experimental results. The agreement is satisfactory in most cases but there are some exceptions where the discrepancy between theory and experiment is significant. The derived isotropic van der Waals coefficients range between 37 and 50 E(H)a(0)(6) and the orientation-dependent coefficients between 2 and -1 …


Pressure Dissociation Of Integration Host Factor-Dna Complexes Reveals Flexibility-Dependent Structural Variation At The Protein-Dna Interface, Donald F. Senear, Vira Tretyachenko-Ladokhina, Michael L. Opel, Kimberly A. Aeling, G. Wesley Hatfield, Laurie M. Franklin, Reuben C. Darlington, J. B. A. Ross Mar 2007

Pressure Dissociation Of Integration Host Factor-Dna Complexes Reveals Flexibility-Dependent Structural Variation At The Protein-Dna Interface, Donald F. Senear, Vira Tretyachenko-Ladokhina, Michael L. Opel, Kimberly A. Aeling, G. Wesley Hatfield, Laurie M. Franklin, Reuben C. Darlington, J. B. A. Ross

Chemistry and Biochemistry Faculty Publications

E. coli Integration host factor (IHF) condenses the bacterial nucleoid by wrapping DNA. Previously, we showed that DNA flexibility compensates for structural characteristics of the four consensus recognition elements associated with specific binding (Aeling et al., J. Biol. Chem. 281, 39236-39248, 2006). If elements are missing, high-affinity binding occurs only if DNA deformation energy is low. In contrast, if all elements are present, net binding energy is unaffected by deformation energy. We tested two hypotheses for this observation: in complexes containing all elements, (1) stiff DNA sequences are less bent upon binding IHF than flexible ones; or (2) DNA sequences …


Climate Correlates Of 20 Years Of Trophic Changes In A High-Elevation Riparian System, Thomas E. Martin Feb 2007

Climate Correlates Of 20 Years Of Trophic Changes In A High-Elevation Riparian System, Thomas E. Martin

Wildlife Biology Faculty Publications

The consequences of climate change for ecosystem structure and function remain largely unknown. Here, I examine the ability of climate variation to explain long-term changes in bird and plant populations, as well as trophic interactions in a high-elevation riparian system in central Arizona, USA, based on 20 years of study. Abundances of dominant deciduous trees have declined dramatically over the 20 years, correlated with a decline in overwinter snowfall. Snowfall can affect overwinter presence of elk, whose browsing can significantly impact deciduous tree abundance. Thus, climate may affect the plant community indirectly through effects on herbivores, but may also act …