Digital Commons Network^™

Vortices In Bose-Einstein Condensates: Some Recent Developments, Panos Kevrekidis, R. Carretero-Gonzalez, D. J. Frantzeskakis, I. G. Kevrekidis

Panos Kevrekidis

In this brief review we summarize a number of recent developments in the study of vortices in Bose-Einstein condensates, a topic of considerable theoretical and experimental interest in the past few years. We examine the generation of vortices by means of phase imprinting, as well as via dynamical instabilities. Their stability is subsequently examined in the presence of purely magnetic trapping, and in the combined presence of magnetic and optical trapping. We then study pairs of vortices and their interactions, illustrating a reduced description in terms of ordinary differential equations for the vortex centers. In the realm of two vortices …

Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk

Todd M. Tripp

Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable depletion of D onto dust grains. To test this scenario, we have obtained high signal-to-noise, high resolution profiles of the refractory ion Ti II along seven Galactic sightlines with D/H ranging from 0.65 to 2.1 × 10−5. These measurements, acquired with the recently upgraded Keck/HIRES spectrometer, indicate a correlation between Ti/H and D/H at the > 95% c.l. Therefore, our observations support the interpretation that D/H scatter …

Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk

Astronomy Department Faculty Publication Series

Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable depletion of D onto dust grains. To test this scenario, we have obtained high signal-to-noise, high resolution profiles of the refractory ion Ti II along seven Galactic sightlines with D/H ranging from 0.65 to 2.1 × 10−5. These measurements, acquired with the recently upgraded Keck/HIRES spectrometer, indicate a correlation between Ti/H and D/H at the > 95% c.l. Therefore, our observations support the interpretation that D/H scatter …

In Vivo Dose-Response Of Insects To Hz-2v Infection, John P. Burand, Christopher P. Rallis

John Burand

Background Hz-2V infection of female Helicoverpa zea moths is manifested as insects that are either sterile "agonadal" individuals with malformed reproductive tissues or fertile asymptomatic carriers which are capable of transmitting virus on to their progeny. Virus infected progeny arising from eggs laid by asymptomatic carrier females may themselves be either sterile agonadals or asymptomatic carriers. Results By injecting virus into female moths, a correlation was established between virus doses administered to the females and the levels of resulting asymptomatic and sterile progeny. Conclusions The results of these experiments indicate that high virus doses produced a higher level of agonadal …

Allele Specific Synthetic Lethality Between Pric And Dnaats Alleles At The Permissive Temperature Of 30°C In E. Coli K-12, Steven Sandler, Tania Hinds

Steven Sandler

Background DnaA is an essential protein in the regulation and initiation of DNA replication in many bacteria. It forms a protein-DNA complex at oriC to which DnaC loads DnaB. DNA replication forks initiated at oriC by DnaA can collapse on route to the terminus for a variety of reasons. PriA, PriB, PriC, DnaT, Rep and DnaC form multiple pathways to restart repaired replication forks. DnaC809 and dnaC809,820 are suppressors of priA2::kan mutant phenotypes. The former requires PriC and Rep while the latter is independent of them. RnhA339::cat mutations allow DnaA-independent initiation of DNA replication. Results It is shown herein that …

The Topology, Geometry And Conformal Structure Of Properly Embedded Minimal Surfaces, Pascal Collin, Robert Kusner, William H. Meeks, Harold Rosenberg

Robert Kusner

This paper develops new tools for understanding surfaces with more than one end and infinite topology which are properly minimally embedded in Euclidean three-space. On such a surface, the set of ends forms a totally disconnected compact Hausdorff space, naturally ordered by the relative heights of the ends in space. One of our main results is that the middle ends of the surface have quadratic area growth, and are thus not limit ends. This implies that the surface can have at most two limit ends, which occur at the top and bottom of the ordering, and thus only a countable …

On A Theorem Of Peters On Automorphisms Of Kahler Surfaces, Weimin Chen Chen

Weimin Chen

For any K¨ahler surface which admits no nonzero holomorphic vectorfields, we consider the group of holomorphic automorphisms which induce identity on the second rational cohomology. Assuming the canonical linear system is without base points and fixed components, C.A.M. Peters [12] showed that this group is trivial except when the K¨ahler surface is of general type and either c21 = 2c2 or c21 = 3c2 holds. Moreover, this group is a 2-group in the former case, and is a 3-group in the latter. The purpose of this note is to give further information about this group. In particular, we show that …

Dna Microarray Analysis Of Nitrogen Fixation And Fe(Iii) Reduction In Geobacter Sulfurreducens, Jennifer Webster, Barbara A. Methé, Kelly P. Nevin, Jessica E. Butler, Derek Lovley

Derek Lovley

A DNA microarray representing the genome of Geobacter sulfurreducens was constructed for use in global gene expression profiling of cells under steady-state conditions with acetate as the electron donor and Fe(III) or fumarate as the electron acceptor. Reproducible differences in transcript levels were also observed in comparisons between cells grown with ammonia and those fixing atmospheric nitrogen. There was a high correlation between changes in transcript levels determined with microarray analyses and an evaluation of a subset of the genome with quantitative PCR. As expected, cells required to fix nitrogen had higher levels of transcripts of genes associated with nitrogen …

Investigation Of Disinfection Byproduct Precursors In The Wachusett Reservoir Watershed, Darleen P. Bryan

Environmental & Water Resources Engineering Masters Projects

The disinfection of drinking water with chlorine was implemented as early as 1908 in an effort to inactivate water borne pathogens. However, chlorine reacts with naturally occurring organic' matter in water to form a host of chlorination byproducts. The possible detrimental health effects from exposure to these byproducts lead to the development offederal regulations for disinfection byproducts (DBPs) in drinking water. Most recently, standards were reduced to 80 ug/L for trihalomethanes, and 60 ug/L for haloacetic acids. The drinking water supplied by the Massachusetts Water Resources Authority (MWRA) has approached and sometimes exceeded the concern level at a few locations …

Simulation Of Evapotranspiration And Rainfall-Runoff For The Stillwater River Watershed In Central Massachusetts, Kavitha M. Ambikadevi

Environmental & Water Resources Engineering Masters Projects

Preliminary studies were conducted on the application of the TOPMODEL to the 3.1.6 me Stillwater River watershed in the Wachusett reservoir basin. TOPMODEL is a physically based - semi distributed hydrological model, which simulates rainfall runoff at a daily or sub-daily time steps. TOPMODEL, version 95.02 was used for the modeling studies. This version of TOPMODEL assumes an exponential transmissivity function for the soil and a first order hyperbolic recession curve for the baseflow. TOPMODEL estimates runoff as the sum of base flow, inflltration "excess overland flow and saturation excess overland flow. Inflltration excess overland flow is modeled using the …

My Life With Polymer Science: Scientific And Personal Memoirs, Otto Vogl

Emeritus Faculty Author Gallery

My "life story" will begin with my formative years, my childhood and student days at the University of Vienna, including my dissertation. It will be followed by my teaching appointment as an Instructor at the II. Chemical Institute of the University of Vienna. The urge to see other lands, learn other languages and scientific methods led to the Wandering Years that brought me to the United States. After three years spent as a Research Associate at the University of Michigan and at Princeton University I spent more than 13 years in an industrial career at the Du Pont Company in …

My Life With Polymer Science: Scientific And Personal Memoirs, Otto Vogl

Otto Vogl

My "life story" will begin with my formative years, my childhood and student days at the University of Vienna, including my dissertation. It will be followed by my teaching appointment as an Instructor at the II. Chemical Institute of the University of Vienna. The urge to see other lands, learn other languages and scientific methods led to the Wandering Years that brought me to the United States. After three years spent as a Research Associate at the University of Michigan and at Princeton University I spent more than 13 years in an industrial career at the Du Pont Company in …

Low Background Techniques For The Borexino Nylon Vessels, Andrea Pocar

Andrea Pocar

Borexino is an organic liquid scintillator underground detector for low energy solar neutrinos. The experiment has to satisfy extremely stringent low background requirements. The thin nylon spherical scintillator containment vessel has to meet cleanliness and low radioactivity levels second only, within the detector, to the scintillator itself. Overall, the background from the vessel in the fiducial volume of the detector must be kept at the level of one event per day or better. The requirements, design choices, results from laboratory tests, and fabrication techniques that have been adopted to meet this goal are presented. Details of the precautions taken during …

In Situ Expression Of Nigd In Geobacteraceae In Subsurface Sediments, Dawn E. Holmes, Kelly P. Nevin, Derek Lovley

Kelly Nevin

In order to determine whether the metabolic state of Geobacteraceae involved in bioremediation of subsurface sediments might be inferred from levels of mRNA for key genes, in situ expression of nifD, a highly conserved gene involved in nitrogen fixation, was investigated. When Geobacter sulfurreducens was grown without a source of fixed nitrogen in chemostats with acetate provided as the limiting electron donor and Fe(III) as the electron acceptor, levels of nifD transcripts were 4 to 5 orders of magnitude higher than in chemostat cultures provided with ammonium. In contrast, the number of transcripts of recA and the 16S rRNA gene …

Adaptation And Sustainability In A Small Arctic Community: Results Of An Agent-Based Simulation Model, Matthew Berman, Craig Nicolson, Gary Kofinas, Joe Tetlichi, Stephanie Martin

Craig Nicolson

Climate warming and resource development could alter key Arctic ecosystem functions that support fish and wildlife resources harvested by local indigenous communities. A different set of global forces—government policies and tourism markets—increasingly directs local cash economies that communities use to support subsistence activities. Agent-based computational models (ABMs) contribute to an integrated assessment of community sustainability by simulating how people interact with each other and adapt to changing economic and environmental conditions. Relying on research and local knowledge to provide rules and parameters for individual and collective decision making, our ABM generates hypothetical social histories as adaptations to scenario-driven changes in …

Charging-Induced Asymmetry In Molecular Conductors, Eric Polizzi, S. Datta, A. Ghosh, M. Paullson, F. Zahhid

Eric Polizzi

We investigate the origin of asymmetry in various measured current-voltage (I-V) characteristics of molecules with no inherent spatial asymmetry, with particular focus on a recent break junction measurement. We argue that such asymmetry arises due to unequal coupling with the contacts and a consequent difference in charging effects, which can only be captured in a self-consistent model for molecular conduction. The direction of the asymmetry depends on the sign of the majority carriers in the molecule. For conduction through highest occupied molecular orbitals (i.e., HOMO or p-type conduction), the current is smaller for positive voltage on the stronger contact, while …

Permaculture At Umass-Amherst: Garden Share Project, Madeleine K. Charney

Madeleine K. Charney

Student-run project at UMass-Amherst which highlights the value of growing and eating local and organic foods.

Permaculture At Umass-Amherst: Garden Share Project, Madeleine K. Charney

University Libraries Publication Series

Student-run project at UMass-Amherst which highlights the value of growing and eating local and organic foods.

Field-And Temperature-Induced Topological Phase Transitions In Three Dimensional N-Component London Superconductor, J. Smiseth, E. Smorgrav, Egor Babaev, A. Sudbo

Egor Babaev

The phase diagram and critical properties of the $N$-component London superconductor are studied both analytically and through large-scale Monte-Carlo simulations in $d=2+1$ dimensions (components here refer to different replicas of the complex scalar field). Examples are given of physical systems to which this model is applicable. The model with different bare phase stiffnesses for each component, is a model of superconductivity which should arise out of metallic phases of light atoms under extreme pressure. A projected mixture of electronic and protonic condensates in liquid metallic hydrogen under extreme pressure is the simplest example, corresponding to N=2. These are such that …

The O Vi Absorbers Toward Pg 0953+415: High-Metallicity, Cosmic-Web Gas Far From Luminous Galaxies, Todd M. Tripp, Bastien Aracil, David V. Bowen, Edward B. Jenkins

Todd M. Tripp

The spectrum of the low-redshift QSO PG0953+415 shows two strong, intervening O VI absorption systems. To study the nature of these absorbers, we have used the Gemini Multiobject Spectrograph to conduct a deep spectroscopic galaxy redshift survey in the 5' x 5' field centered on the QSO. This survey is fully complete for r' < 19.7 and is 73% complete for r' < 21.0. We find three galaxies at the redshift of the higher-z O VI system (z = 0.14232) including a galaxy at projected distance rho = 155 kpc. We find no galaxies in the Gemini field at the redshift of the lower-z O VI absorber (z = 0.06807), which indicates that the nearest galaxy is more than 195 kpc away or has L < 0.04 L*. Previous shallower surveys covering a larger field have shown that the z = 0.06807 O VI absorber is affiliated with a group/filament of galaxies, but the nearest known galaxy has rho = 736 kpc. The z = 0.06807 absorber is notable for several reasons. The absorption profiles reveal simple kinematics indicative of quiescent material. The H I line widths and good alignment of the H I and metal lines favor photoionization and, moreover, the column density ratios imply a high metallicity: [M/H] = -0.3 +/- 0.12. The z = 0.14232 O VI system is more complex and less constrained but also indicates a relatively high metallicity. Using galaxy redshifts from SDSS, we show that both of the PG0953+415 O VI absorbers are located in large-scale filaments of the cosmic web. Evidently, some regions of the web filaments are highly metal enriched. We discuss the origin of the high-metallicity gas and suggest that the enrichment might have occurred long ago (at high z).

Nelig Meeting - November 19, 2004, New England Library Instruction Group

New England Library Instruction Group

NELIG quarterly meeting.

Classical Physics And Quantum Loops, Barry R. Holstein, John Donoghue

John Donoghue

The standard picture of the loop expansion associates a factor of h-bar with each loop, suggesting that the tree diagrams are to be associated with classical physics, while loop effects are quantum mechanical in nature. We discuss examples wherein classical effects arise from loop contributions and display the relationship between the classical terms and the long range effects of massless particles.

Mgm V. Grokster, Brief Amici Curiae Of The Computer & Communications Industry Association And Internet Archive, In Opposition To The Writ Of Certiorari, To The United States Supreme Court, Laura Quilter, Peter Jaszi

Laura Quilter

Amicus on behalf of the Internet Archive and the CCIA, requesting the Supreme Court of the United States to deny the petition for certiorari in the MGM v. Grokster case.

Evidence For Involvement Of An Electron Shuttle In Electricity Generation By Geothrix Fermentans, Daiel R. Bond, Derek Lovley

Derek Lovley

In experiments performed using graphite electrodes poised by a potentiostat (+200 mV versus Ag/AgCl) or in a microbial fuel cell (with oxygen as the electron acceptor), the Fe(III)-reducing organism Geothrix fermentans conserved energy to support growth by coupling the complete oxidation of acetate to reduction of a graphite electrode. Other organic compounds, such as lactate, malate, propionate, and succinate as well as components of peptone and yeast extract, were utilized for electricity production. However, electrical characteristics and the results of shuttling assays indicated that unlike previously described electrode-reducing microorganisms, G. fermentans produced a compound that promoted electrode reduction. This is …

Pictures From My Life With Polymer Science: Album 1, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.

Pictures From My Life With Polymer Science: Album 01, Otto Vogl

Otto Vogl

No abstract provided.

Surface Mass Balance Of The Ward Hunt Ice Rise And Ward Hunt Ice Shelf, Ellesmere Island, Nunavut, Canada, C. Braun, D. R. Hardy, Raymond S. Bradley, V. Sahanatien

Raymond S Bradley

The Ward Hunt Ice Rise and Ward Hunt Ice Shelf, located on Ellesmere Island, Canada, are two of the northernmost land ice masses on the North American continent. Surface mass balance measurements (excluding calving and subice processes) began in 1959 on the ice rise and in 1966 on the ice shelf but were frequently interrupted, most recently between 1986 and 2002. The surface balance of the ice rise and ice shelf follows the temporal pattern seen on other measured High Arctic glaciers. The overall surface mass losses over the last 45 years have been comparatively low (1.68 m water equivalent …

Radio Frequency Id And Privacy With Information Goods, Laura Quilter, Nathan Good, John Han, Elizabeth Miles, David Molnar, Deirdre Mulligan, Jennifer M. Urban, David Wagner

Laura Quilter

No abstract provided.

The 20th Annual International Conference On Soils, Sediments And Water

Annual Conference on Soils, Sediments and Water: Abstracts

Conference at a Glance

Monday, October 18, 2004

Workshops

(Workshop #1: 9:00 am-5:00 pm, Workshops #2-3: 10:00 am-5:00 pm, Workshops #4-5: 1:00-5:00 pm, Workshop #6: 2:00-5:00 pm)

Workshop #1: Modeling Vapor Attenuation Workshop: A Study of Vapor Intrusion Modeling in the Context of EPA’s Guidance

Workshop # 2: Theory and Use of Field Portable X-ray Fluorescence for Soil Analysis

Workshop #3: In-Situ Chemical Oxidation Workshop

Workshop #4: The Triad Approach to Managing Decision Uncertainty for Better Cleanup Projects

Workshops #5: The Role of Anaerobic Biodegradation Process in Passive and Enhanced Monitored Natural Attenuation Programs

Workshop #6: Environmental Fate of Hydrocarbons …

Pictures From My Life With Polymer Science: Album 2, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.