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Louisiana State University

2009

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Inflation, Quantum Fields, And Cmb Anisotropies, Iván Agulló, José Navarro-Salas, Gonzalo J. Olmo, Leonard Parker Dec 2009

Inflation, Quantum Fields, And Cmb Anisotropies, Iván Agulló, José Navarro-Salas, Gonzalo J. Olmo, Leonard Parker

Faculty Publications

Inflationary cosmology has proven to be the most successful at predicting the properties of the anisotropies observed in the cosmic microwave background (CMB). In this essay we show that quantum field renormalization significantly influences the generation of primordial perturbations and hence the expected measurable imprint of cosmological inflation on the CMB. However, the new predictions remain in agreement with observation, and in fact favor the simplest forms of inflation. In the near future, observations of the influence of gravitational waves from the early universe on the CMB will test our new predictions. © 2009 World Scientific Publishing Company.

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Theory Of Thermal Conductivity In Extended-S State Superconductors: Application To Ferropnictides, V. Mishra, A. Vorontsov, P. J. Hirschfeld, I. Vekhter Dec 2009

Theory Of Thermal Conductivity In Extended-S State Superconductors: Application To Ferropnictides, V. Mishra, A. Vorontsov, P. J. Hirschfeld, I. Vekhter

Faculty Publications

Within a two-band model for the recently discovered ferropnictide materials, we calculate the thermal conductivity assuming general superconducting states of A1g (" s -wave") symmetry, considering both currently popular isotropic "sign-changing" s states and states with strong anisotropy, including those which manifest nodes or deep minima of the order parameter. We consider both intraband and interband disorder scattering effects, and show that in situations where a low-temperature linear- T term exists in the thermal conductivity, it is not always "universal" as in d -wave superconductors. We discuss the conditions under which such a term can disappear, as well as how …

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Auger Decay In Krypton Induced By Attosecond Pulse Trains And Twin Pulses, Christian Buth, Kenneth J. Schafer Dec 2009

Auger Decay In Krypton Induced By Attosecond Pulse Trains And Twin Pulses, Christian Buth, Kenneth J. Schafer

Faculty Publications

Using attoscience, we study the electron correlations responsible for Auger decay in krypton atoms. The Auger decay is induced by a pulse train or a twin pulse composed of subpulses of attosecond duration. During the Auger decay an optical dressing laser may be present. Interference effects between the ejected Auger electron wave packets are predicted.

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Bloch Sphere-Like Construction Of Su(3) Hamiltonians Using Unitary Integration, Sai Vinjanampathy, A. R.P. Rau Dec 2009

Bloch Sphere-Like Construction Of Su(3) Hamiltonians Using Unitary Integration, Sai Vinjanampathy, A. R.P. Rau

Faculty Publications

The Bloch sphere is a familiar and useful geometrical picture of the time evolution of a single spin or a quantal two-level system. The analogous geometrical picture for three-level systems is presented with several applications. The relevant SU(3) group and su(3) algebra are eight-dimensional objects and are realized in our picture as two four-dimensional manifolds that describe the time evolution operator. The first, called the base manifold, is the counterpart of the S2 Bloch sphere, whereas the second, called the fiber, generalizes the single U(1) phase of a single spin. Now four dimensional, it breaks down further into smaller objects …

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Erratum: All-Sky Search For Periodic Gravitational Waves In Ligo S4 Data (Physical Review D (2008) 77 (022001)), B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, G. Billingsley, R. Biswas Dec 2009

Erratum: All-Sky Search For Periodic Gravitational Waves In Ligo S4 Data (Physical Review D (2008) 77 (022001)), B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, G. Billingsley, R. Biswas

Faculty Publications

No abstract provided.

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Monte Carlo Simulation Of The Neutron Spectral Fluence And Dose Equivalent For Use In Shielding A Proton Therapy Vault, Yuanshui Zheng, Wayne Newhauser, Eric Klein, Daniel Low Dec 2009

Monte Carlo Simulation Of The Neutron Spectral Fluence And Dose Equivalent For Use In Shielding A Proton Therapy Vault, Yuanshui Zheng, Wayne Newhauser, Eric Klein, Daniel Low

Faculty Publications

Neutron production is of principal concern when designing proton therapy vault shielding. Conventionally, neutron calculations are based on analytical methods, which do not accurately consider beam shaping components and nozzle shielding. The goal of this study was to calculate, using Monte Carlo modeling, the neutron spectral fluence and neutron dose equivalent generated by a realistic proton therapy nozzle and evaluate how these data could be used in shielding calculations. We modeled a contemporary passive scattering proton therapy nozzle in detail with the MCNPX simulation code. The neutron spectral fluence and dose equivalent at various locations in the treatment room were …

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Reply To Zimmerman Et Al.: The Space Of Single Domain Protein Structures Is Continuous And Highly Connected, Jeffrey Skolnick, Michal Brylinski, Seung Yup Lee Dec 2009

Reply To Zimmerman Et Al.: The Space Of Single Domain Protein Structures Is Continuous And Highly Connected, Jeffrey Skolnick, Michal Brylinski, Seung Yup Lee

Faculty Publications

No abstract provided.

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Near-Infrared Fluorescent Nanogumbos For Biomedical Imaging, David K. Bwambok, Bilal El-Zahab, Santhosh K. Challa, Min Li, Lin Chandler, Gary A. Baker, Isiah M. Warner Dec 2009

Near-Infrared Fluorescent Nanogumbos For Biomedical Imaging, David K. Bwambok, Bilal El-Zahab, Santhosh K. Challa, Min Li, Lin Chandler, Gary A. Baker, Isiah M. Warner

Faculty Publications

Herein, we report on near-infrared (NIR) fluorescent nanoparticles generated from an emergent class of materials we refer to as a Group of Uniform Materials Based on Organic Salts (GUMBOS). GUMBOS are largely frozen ionic liquids, although the concept is more general and is also easily applied to solid ionic materials with melting points in excess of 100 °C. Nanoparticles based on GUMBOS (nanoGUMBOS) derived from a NIR fluorophore are prepared using a reprecipitation method and evaluated for in vivo fluorescence imaging. Due to their uniformity, single-step preparation, and composite nature, nanoGUMBOS help to resolve issues with dye leakage problems innate …

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Measurement Of The Inclusive Isolated Prompt Photon Cross Section In Pp̄ Collisions At S=1.96tev Using The Cdf Detector, T. Aaltonen, J. Adelman, B. Álvarez González, S. Amerio, D. Amidei, A. Anastassov, A. Annovi, J. Antos, G. Apollinari, A. Apresyan, T. Arisawa, A. Artikov, J. Asaadi, W. Ashmanskas, A. Attal, A. Aurisano, F. Azfar, W. Badgett, A. Barbaro-Galtieri, V. E. Barnes, B. A. Barnett, P. Barria, P. Bartos, G. Bauer, P. H. Beauchemin, F. Bedeschi, D. Beecher, S. Behari Dec 2009

Measurement Of The Inclusive Isolated Prompt Photon Cross Section In Pp̄ Collisions At S=1.96tev Using The Cdf Detector, T. Aaltonen, J. Adelman, B. Álvarez González, S. Amerio, D. Amidei, A. Anastassov, A. Annovi, J. Antos, G. Apollinari, A. Apresyan, T. Arisawa, A. Artikov, J. Asaadi, W. Ashmanskas, A. Attal, A. Aurisano, F. Azfar, W. Badgett, A. Barbaro-Galtieri, V. E. Barnes, B. A. Barnett, P. Barria, P. Bartos, G. Bauer, P. H. Beauchemin, F. Bedeschi, D. Beecher, S. Behari

Faculty Publications

A measurement of the cross section for the inclusive production of isolated photons by the CDF experiment at the Fermilab Tevatron collider is presented. The measurement covers the pseudorapidity region |ηγ|<1.0 and the transverse energy range ETγ>30GeV and is based on 2.5fb-1 of integrated luminosity. The sample is almost a factor of 7 larger than those used for recent published results and extends the ETγ coverage by 100 GeV. The result agrees with next-to-leading order perturbative QCD calculations within uncertainties over the range 50

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Asymptotic Falloff Of Local Waveform Measurements In Numerical Relativity, Denis Pollney, Christian Reisswig, Nils Dorband, Erik Schnetter, Peter Diener Dec 2009

Asymptotic Falloff Of Local Waveform Measurements In Numerical Relativity, Denis Pollney, Christian Reisswig, Nils Dorband, Erik Schnetter, Peter Diener

Faculty Publications

We examine current numerical relativity computations of gravitational waves, which typically determine the asymptotic waves at infinity by extrapolation from finite (small) radii. Using simulations of a black hole binary with accurate wave extraction at r=1000M, we show that extrapolations from the near zone are self-consistent in approximating measurements at this radius, although with a somewhat reduced accuracy. We verify that ψ4 is the dominant asymptotic contribution to the gravitational energy (as required by the peeling theorem) but point out that gauge effects may complicate the interpretation of the other Weyl components. © 2009 The American Physical Society.

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Phylogeny Of The Macaques (Cercopithecidae: Macaca) Based On Alu Elements, Jing Li, Kyudong Han, Jinchuan Xing, Heui Soo Kim, Jeffrey Rogers, Oliver A. Ryder, Todd Disotell, Bisong Yue, Mark A. Batzer Dec 2009

Phylogeny Of The Macaques (Cercopithecidae: Macaca) Based On Alu Elements, Jing Li, Kyudong Han, Jinchuan Xing, Heui Soo Kim, Jeffrey Rogers, Oliver A. Ryder, Todd Disotell, Bisong Yue, Mark A. Batzer

Faculty Publications

Genus Macaca (Cercopithecidae: Papionini) is one of the most successful primate radiations. Despite previous studies on morphology and mitochondrial DNA analysis, a number of issues regarding the details of macaque evolution remain unsolved. Alu elements are a class of non-autonomous retroposons belonging to short interspersed elements that are specific to the primate lineage. Because retroposon insertions show very little homoplasy, and because the ancestral state (absence of the SINE) is known, Alu elements are useful genetic markers and have been utilized for analyzing primate phylogenentic relationships and human population genetic relationships. Using PCR display methodology, 298 new Alu insertions have …

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Internal Priming: An Opportunistic Pathway For L1 And Alu Retrotransposition In Hominins, Deepa Srikanta, Shurjo K. Sen, Erin M. Conlin, Mark A. Batzer Dec 2009

Internal Priming: An Opportunistic Pathway For L1 And Alu Retrotransposition In Hominins, Deepa Srikanta, Shurjo K. Sen, Erin M. Conlin, Mark A. Batzer

Faculty Publications

Retrotransposons, specifically Alu and L1 elements, have been especially successful in their expansion throughout primate genomes. While most of these elements integrate through an endonuclease-mediated process termed target primed reverse transcription, a minority integrate using alternative methods. Here we present evidence for one such mechanism, which we term internal priming and demonstrate that loci integrating through this mechanism are qualitatively different from "classical" insertions. Previous examples of this mechanism are limited to cell culture assays, which show that reverse transcription can initiate upstream of the 3′ poly-A tail during retrotransposon integration. To detect whether this mechanism occurs in vivo as …

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Nonsingular Ekpyrotic/Cyclic Model In Loop Quantum Cosmology, Thomas Cailleteau, Parampreet Singh, Kevin Vandersloot Dec 2009

Nonsingular Ekpyrotic/Cyclic Model In Loop Quantum Cosmology, Thomas Cailleteau, Parampreet Singh, Kevin Vandersloot

Faculty Publications

We study the role of nonperturbative quantum gravity effects in the ekpyrotic/cyclic model using the effective framework of loop quantum cosmology in the presence of anisotropies. We show that quantum geometric modifications to the dynamical equations near the Planck scale as understood in the quantization of Bianchi-I spacetime in loop quantum cosmology lead to the resolution of classical singularity and result in a nonsingular transition of the Universe from the contracting to the expanding branch. In the Planck regime, the Universe undergoes multiple small bounces and the anisotropic shear remains bounded throughout the evolution. A novel feature, which is absent …

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Strong Field Double Ionization Of H2: Insights From Nonlinear Dynamics, F. Mauger, C. Chandre, T. Uzer Dec 2009

Strong Field Double Ionization Of H2: Insights From Nonlinear Dynamics, F. Mauger, C. Chandre, T. Uzer

Faculty Publications

The uncorrelated ("sequential") and correlated ("nonsequential") double ionization of the H2 molecule in strong laser pulses is investigated using tools of nonlinear dynamics. We focus on the phase-space dynamics of this system, specifically by finding the dynamical structures that regulate these ionization processes. The emerging picture complements the recollision scenario by clarifying the distinct roles played by the recolliding and core electrons. Our analysis leads to verifiable predictions of the intensities where qualitative changes in ionization occur. We also show how these findings depend on the internuclear distance. © 2009 Elsevier B.V. All rights reserved.

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Detrital U-Pb Zircon Dating Of Lower Ordovician Syn-Arc-Continent Collision Conglomerates In The Irish Caledonides, Peter D. Clift, Andrew Carter, Amy E. Draut, Hoang Van Long, David M. Chew, Hans A. Schouten Dec 2009

Detrital U-Pb Zircon Dating Of Lower Ordovician Syn-Arc-Continent Collision Conglomerates In The Irish Caledonides, Peter D. Clift, Andrew Carter, Amy E. Draut, Hoang Van Long, David M. Chew, Hans A. Schouten

Faculty Publications

The Early Ordovician Grampian Orogeny in the British Isles represents a classic example of collision between an oceanic island arc and a passive continental margin, starting around 480 Ma. The South Mayo Trough in western Ireland preserves a complete and well-dated sedimentary record of arc collision. We sampled sandstones and conglomerates from the Rosroe, Maumtrasna and Derryveeny Formations in order to assess erosion rates and patterns during and after arc collision. U-Pb dating of zircons reveals a provenance dominated by erosion from the upper levels of the Dalradian Supergroup (Southern Highland and Argyll Groups), with up to 20% influx from …

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Faculty Senate Resolution 09-07, Louisiana State University And Agricultural & Mechanical College Dec 2009

Faculty Senate Resolution 09-07, Louisiana State University And Agricultural & Mechanical College

LSU Faculty Senate Publications

Faculty Senate Resolution regarding conditions and procedures for furlough plans, adopted on December 7, 2009.

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Faculty Senate Resolution 09-10, Louisiana State University And Agricultural & Mechanical College Dec 2009

Faculty Senate Resolution 09-10, Louisiana State University And Agricultural & Mechanical College

LSU Faculty Senate Publications

Faculty Senate Resolution on University admissions standards and the restructuring of Louisiana higher education, adopted on December 7, 2009.

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Precise Calibration Of Ligo Test Mass Actuators Using Photon Radiation Pressure, E. Goetz, P. Kalmus, S. Erickson, R. L. Savage, G. Gonzalez, K. Kawabe, M. Landry, S. Marka, B. O'Reilly, K. Riles, D. Sigg, P. Willems Dec 2009

Precise Calibration Of Ligo Test Mass Actuators Using Photon Radiation Pressure, E. Goetz, P. Kalmus, S. Erickson, R. L. Savage, G. Gonzalez, K. Kawabe, M. Landry, S. Marka, B. O'Reilly, K. Riles, D. Sigg, P. Willems

Faculty Publications

Precise calibration of kilometer-scale interferometric gravitational wave detectors is crucial for source localization and waveform reconstruction. A technique that uses the radiation pressure of a power-modulated auxiliary laser to induce calibrated displacements of one of the ∼10 kg arm cavity mirrors, a so-called photon calibrator, has been demonstrated previously and has recently been implemented on the LIGO detectors. In this paper, we discuss the inherent precision and accuracy of the LIGO photon calibrators and several improvements that have been developed to reduce the estimated voice coil actuator calibration uncertainties to less than 2% (1σ). These improvements include accounting for rotation-induced …

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A Tale Of Two Functions: Enzymatic Activity And Translational Repression By Carboxyltransferase, Glen Meades, Brian K. Benson, Anne Grove, Grover L. Waldrop Dec 2009

A Tale Of Two Functions: Enzymatic Activity And Translational Repression By Carboxyltransferase, Glen Meades, Brian K. Benson, Anne Grove, Grover L. Waldrop

Faculty Publications

Acetyl-CoA Carboxylase catalyzes the first committed step in fatty acid synthesis. Escherichia coli acetyl-CoA carboxylase is composed of biotin carboxylase, carboxyltransferase and biotin carboxyl carrier protein functions. The accA and accD genes that code for the α- and β-subunits, respectively, are not in an operon, yet yield an α2β2 carboxyltransferase. Here, we report that carboxyltransferase regulates its own translation by binding the mRNA encoding its subunits. This interaction is mediated by a zinc finger on the β-subunit; mutation of the four cysteines to alanine diminished nucleic acid binding and catalytic activity. Carboxyltransferase binds the coding regions of both subunit mRNAs …

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Yy1'S Dna-Binding Motifs In Mammalian Olfactory Receptor Genes, Christopher D. Faulk, Joomyeong Kim Dec 2009

Yy1'S Dna-Binding Motifs In Mammalian Olfactory Receptor Genes, Christopher D. Faulk, Joomyeong Kim

Faculty Publications

Background: YY1 is an epigenetic regulator for a large number of mammalian genes. While performing genome-wide YY1 binding motif searches, we discovered that the olfactory receptor (OLFR) genes have an unusual cluster of YY1 binding sites within their coding regions. The statistical significance of this observation was further analyzed. Results: About 45% of the olfactory genes in the mouse have a range of 4-8 YY1 binding sites within their respective 1 kb coding regions. Statistical analyses indicate that this enrichment of YY1 motifs has likely been driven by unknown selection pressures at the DNA level, but not serendipitously by some …

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Quantum Forbidden-Interval Theorems For Stochastic Resonance, Mark M. Wilde, Bart Kosko Dec 2009

Quantum Forbidden-Interval Theorems For Stochastic Resonance, Mark M. Wilde, Bart Kosko

Faculty Publications

We extend the classical forbidden-interval theorems for a stochastic-resonance noise benefit in a nonlinear system to a quantum-optical communication model and a continuous-variable quantum key distribution model. Each quantum forbidden-interval theorem gives a necessary and sufficient condition that determines whether stochastic resonance occurs in quantum communication of classical messages. The quantum theorems apply to any quantum noise source that has finite variance or that comes from the family of infinite-variance alpha-stable probability densities. Simulations show the predicted noise benefits for the basic quantum communication model and the continuous-variable quantum key distribution model. © 2009 IOP Publishing Ltd.

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Optimization Of Quantum Interferometric Metrological Sensors In The Presence Of Photon Loss, Tae Woo Lee, Sean D. Huver, Hwang Lee, Lev Kaplan, Steven B. Mccracken, Changjun Min, Dmitry B. Uskov, Christoph F. Wildfeuer, Georgios Veronis, Jonathan P. Dowling Dec 2009

Optimization Of Quantum Interferometric Metrological Sensors In The Presence Of Photon Loss, Tae Woo Lee, Sean D. Huver, Hwang Lee, Lev Kaplan, Steven B. Mccracken, Changjun Min, Dmitry B. Uskov, Christoph F. Wildfeuer, Georgios Veronis, Jonathan P. Dowling

Faculty Publications

We optimize two-mode entangled number states of light in the presence of loss in order to maximize the extraction of the available phase information in an interferometer. Our approach optimizes over the entire available input Hilbert space with no constraints, other than fixed total initial photon number. We optimize to maximize the Fisher information, which is equivalent to minimizing the phase uncertainty. We find that in the limit of zero loss, the optimal state is the maximally path-entangled (so-called N00N) state, for small loss, the optimal state gradually deviates from the N00N state, and in the limit of large loss, …

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The Behavior Of Novae Light Curves Before Eruption, Andrew C. Collazzi, Bradley E. Schaefer, Limin Xiao, Ashley Pagnotta, Peter Kroll, Klaus Löchel, Arne A. Henden Dec 2009

The Behavior Of Novae Light Curves Before Eruption, Andrew C. Collazzi, Bradley E. Schaefer, Limin Xiao, Ashley Pagnotta, Peter Kroll, Klaus Löchel, Arne A. Henden

Faculty Publications

In 1975, E. R. Robinson conducted the hallmark study of the behavior of classical nova light curves before eruption, and this work has now become part of the standard knowledge of novae. He made three points: 5 out of 11 novae showed pre-eruption rises in the years before eruption, one nova (V446 Her) showed drastic changes in the variability across eruptions, and all but one of the novae (excepting BT Mon) have the same quiescent magnitudes before and after the outburst. This work has not been tested since it came out. We have now tested these results by going back …

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A Holistic Study Of Equatorial Guinea’S President And The Factors That Have Influenced His Policies And Actions, Carly Jade Burt Dec 2009

A Holistic Study Of Equatorial Guinea’S President And The Factors That Have Influenced His Policies And Actions, Carly Jade Burt

Honors Theses

No abstract provided.

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Three-Way Tiling Sets In Two Dimensions, David R. Larson, Peter Massopust, Gestur Ólafsson Dec 2009

Three-Way Tiling Sets In Two Dimensions, David R. Larson, Peter Massopust, Gestur Ólafsson

Faculty Publications

In this article we show that there exist measurable sets W⊂ℝ2 with finite measure that tile ℝ2 in a measurable way under the action of a expansive matrix A, an affine Weyl group W ̃ and a full rank lattice Γ⊂ ℝ 2 . This note is follow-up research to the earlier article "Coxeter groups and wavelet sets" by the first and second authors, and is also relevant to the earlier article "Coxeter groups, wavelets, multiresolution and sampling" by M. Dobrescu and the third author. After writing these two articles, the three authors participated in a workshop at the Banff …

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Direct Measurements Of The Penetration Depth In A Superconducting Film Using Magnetic Force Microscopy, E. Nazaretski, J. P. Thibodaux, I. Vekhter, L. Civale, J. D. Thompson, R. Movshovich Dec 2009

Direct Measurements Of The Penetration Depth In A Superconducting Film Using Magnetic Force Microscopy, E. Nazaretski, J. P. Thibodaux, I. Vekhter, L. Civale, J. D. Thompson, R. Movshovich

Faculty Publications

We report the local measurements of the magnetic penetration depth λ in a superconducting Nb film using magnetic force microscopy (MFM). We developed a method for quantitative extraction of the penetration depth from single-parameter simultaneous fits to the lateral and height profiles of the MFM signal, and demonstrate that the obtained value is in excellent agreement with that obtained from the bulk magnetization measurements. © 2009 American Institute of Physics.

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Staggered T-Structures On Derived Categories Of Equivariant Coherent Sheaves, Pramod N. Achar Dec 2009

Staggered T-Structures On Derived Categories Of Equivariant Coherent Sheaves, Pramod N. Achar

Faculty Publications

Let X be a scheme, and let G be an affine group scheme acting on X. Under reasonable hypotheses on X and G, we construct a t-structure on the derived category of G-equivariant coherent sheaves that in many ways resembles the perverse coherent t-structure, but which incorporates additional information from the G-action. Under certain circumstances, the heart of this t-structure, called the "staggered t-structure," is a finite-length category, and its simple objects are particularly easy to describe. We also exhibit two small examples in which the staggered t-structure is better-behaved than the perverse coherent t-structure. © The Author 2009. Published …

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How Do Animal Mitochondria Tolerate Water Stress?, Michael A. Menze, Steven C. Hand Dec 2009

How Do Animal Mitochondria Tolerate Water Stress?, Michael A. Menze, Steven C. Hand

Faculty Publications

The vast majority of animal species do not tolerate severe water stress, but the encysted embryo of the brine shrimp Artemia franciscana is an exceptionally useful organism to investigate physiological mechanisms for enduring extreme environmental insults. Any substantial reduction in cellular water poses a threat to survival. Nevertheless anhydrobiotic animals survive virtually complete loss of cellular water. The mechanisms that govern " life without water" (anhydrobiosis) are still not well understood. With certain exceptions, it seems that a recurring strategy for tolerating severe water loss involves the accumulation of both low molecular weight solutes (e.g., trehalose or other polyol) and …

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Water Stress Impacts On Bacterial Carbon Monoxide Oxidation On Recent Volcanic Deposits, Carolyn F. Weber, Gary M. King Dec 2009

Water Stress Impacts On Bacterial Carbon Monoxide Oxidation On Recent Volcanic Deposits, Carolyn F. Weber, Gary M. King

Faculty Publications

Water availability oscillates dramatically on young volcanic deposits, and may control the distribution and activity of microbes during early stages of biological succession. Carbon monoxide (CO)-oxidizing bacteria are among the pioneering colonists on volcanic deposits and are subjected to these water stresses. We report here the effects of water potential on CO-oxidizing bacteria in unvegetated (bare) and vegetated (canopy) sites on a 1959 volcanic deposit on Kilauea Volcano (Hawai'i). Time course measurements of water potential showed that average water potentials in the surface layer (0-1 cm) of canopy soil remained between 0.1 and 0 MPa, whereas dramatic diurnal oscillations (for …

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Sphingosine-1-Phosphate Elicits Receptor-Dependent Calcium Signaling In Retinal Amacrine Cells, Scott Crousillac, Jeremy Colonna, Emily Mcmains, Jill Sayes Dewey, Evanna Gleason Dec 2009

Sphingosine-1-Phosphate Elicits Receptor-Dependent Calcium Signaling In Retinal Amacrine Cells, Scott Crousillac, Jeremy Colonna, Emily Mcmains, Jill Sayes Dewey, Evanna Gleason

Faculty Publications

Evidence is emerging indicating that sphingosine-1-phosphate (S1P) participates in signaling in the retina. To determine whether S1P might be involved in signaling in the inner retina specifically, we examine the effects of this sphingolipid on cultured retinal amacrine cells. Whole cell voltage-clamp recordings reveal that S1P activates a cation current that is dependent on signaling through Gi and phospholipase C. These observations are consistent with the involvement of members of the S1P receptor family of G-protein-coupled receptors in the production of the current. Immunocytochemistry and PCR amplification provide evidence for the expression of S1P1R and S1P3R in amacrine cells. The …

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