Physical Sciences and Mathematics Commons^™

Multidecadal North Atlantic Climate Variability And Its Effect On North American Salmon Abundance, Alan Condron, Robert M. Deconto, Raymond S. Bradley, Frances Juanes

Robert M DeConto

Climate variability is now known to play a key role in the abundance of marine fisheries, and must be accounted for to implement sustainable management strategies. We show that North American Atlantic salmon abundance has fluctuated in parallel with the Atlantic Multidecadal Oscillation (AMO); a basin-wide, low frequency climate mode producing cold-warm-cold sea surface temperatures over the last century. During the AMO warm (cool) phase salmon abundance is lower (higher). Changes in sea surface temperature associated with the AMO are most pronounced in the winter season near the Grand Banks of Newfoundland, a known overwintering area for salmon and an …

Long Distance Effects And Strangeness In The Nucleon, John Donoghue, Barry R. Holstein, Tobias Huber, Andreas Ross

John Donoghue

We discuss the calculation of the strange magnetic radius of the proton in chiral perturbation theory. In particular we investigate the low energy component of the loop integrals involving kaons. We separate the chiral calculation into a low energy part and a high energy component through use of a momentum space separation scale. This separation shows that most of the chiral calculation comes from high energies where the effective field theory treatment is not valid. The resulting low energy prediction is in better agreement with dispersive treatments. Finally, we briefly discuss magnetic moments and show how our techniques can help …

54th Spsj Annual Meeting Yokohama, Japan, May 25-27, 2005, Jane C. Vogl, Hiroyuki Ohno

Emeritus Faculty Author Gallery

No abstract provided.

54th Spsj Annual Meeting Yokohama, Japan, May 25-27, 2005, Jane C. Vogl, Hiroyuki Ohno

Otto Vogl

No abstract provided.

Macromolecules In Graz, Austria, December 3, 2004, Otto Vogl, Volker Ribitsch

Emeritus Faculty Author Gallery

No abstract provided.

Macromolecules In Graz, Austria, December 3, 2004, Otto Vogl, Volker Ribitsch

Otto Vogl

No abstract provided.

The 21st Annual International Conference On Soils, Sediments And Water

Annual Conference on Soils, Sediments and Water: Abstracts

Conference at a Glance Monday, October 17, 2005 Workshops (Workshops #1 and #2: 10:00am - 5:00pm; Workshop #3: 1:00 - 5:00pm; Workshop #4: 1:00 - 3:00pm, Workshop #5: 2:00 - 5:00pm) 1) Theory and Use of Field Portable X-ray Fluorescence for Soil Analysis 2) In-Situ Chemical Oxidation Workshop 3) The Role of Anaerobic Biodegradation Processes in Passive and Enhanced Monitored Natural Attenuation Programs 4) Application of Classic and Emerging Techniques in Environmental Forensics 5) Environmental Fate of Hydrocarbons in Soils and Groundwater Tuesday, October 18, 2005 Platform Presentations 8:30am – Noon Session 1: Environmental Biotechnology Session 2: Ecological Restoration and …

Dynamics Of Trapped Bright Solitons In The Presence Of Localized Inhomogeneities, G. Herring, Panos Kevrekidis, R. Carretero-Gonzalez, B. A. Malomed, D. J. Frantzeskakis, A. R. Bishop

Panos Kevrekidis

We examine the dynamics of a bright solitary wave in the presence of a repulsive or attractive localized ``impurity'' in Bose-Einstein condensates (BECs). We study the generation and stability of a pair of steady states in the vicinity of the impurity as the impurity strength is varied. These two new steady states, one stable and one unstable, disappear through a saddle-node bifurcation as the strength of the impurity is decreased. The dynamics of the soliton is also examined in all the cases (including cases where the soliton is offset from one of the relevant fixed points). The numerical results are …

Complete Intersections In Toric Ideals, Eduardo Cattani, Raymond Curran, Alicia Dickenstein

Mathematics and Statistics Department Faculty Publication Series

We present examples which show that in dimension higher than one or codimension higher than two, there exist toric ideals IA such that no binomial ideal contained in IA and of the same dimension is a complete intersection. This result has important implications in sparse elimination theory and in the study of the Horn system of partial differential equations.

Observation Of A Metallic Superfluid In A Numerical Experiment, E. Smorgrav, J. Smiseth, Egor Babaev, A. Sudbo

Egor Babaev

We report the observation, in Monte Carlo simulations, of a novel type of quantum ordered state: {\it the metallic superfluid}. The metallic superfluid features ohmic resistance to counter-flows of protons and electrons, while featuring dissipationless co-flows of electrons and protons. One of the candidates for a physical realization of this remarkable state of matter is hydrogen or its isotopes under high compression. This adds another potential candidate to the presently known quantum dissipationless states, namely superconductors, superfluid liquids and vapours, and supersolids.

Observability Of A Projected New State Of Matter: A Metallic Superfluid, Egor Babaev, Asle Sudbo, N. W. Ashcroft

Egor Babaev

Dissipationless quantum states, such as superconductivity and superfluidity, have attracted interest for almost a century. A variety of systems exhibit these macroscopic quantum phenomena, ranging from superconducting electrons in metals to superfluid liquids, atomic vapours, and even large nuclei. It was recently suggested that liquid metallic hydrogen could form two new unusual dissipationless quantum states, namely the metallic superfluid and the superconducting superfluid. Liquid metallic hydrogen is projected to occur only at an extremely high pressure of about 400 GPa, while pressures on hydrogen of 320 GPa having already been reported. The issue to be adressed is if this state …

An Effective Theory Of Initial Conditions In Inflation, Hael Collins, R. Holman

Physics Department Faculty Publication Series

We examine the renormalization of an effective theory description of a general initial state set in an isotropically expanding space-time, which is done to understand how to include the effects of new physics in the calculation of the cosmic microwave background power spectrum. The divergences that arise in a perturbative treatment of the theory are of two forms: those associated with the properties of a field propagating through the bulk of space-time, which are unaffected by the choice of the initial state, and those that result from summing over the short-distance structure of the initial state. We show that the …

Proxy-Based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity To Method, Predictor Network, Target Season, And Target Domain, S. Rutherford, M. E. Mann, T. J. Osborne, Raymond S. Bradley, K. R. Briffa, M. K. Hughes, P. D. Jones

Raymond S Bradley

Results are presented from a set of experiments designed to investigate factors that may influence proxy-based reconstructions of large-scale temperature patterns in past centuries. The factors investigated include 1) the method used to assimilate proxy data into a climate reconstruction, 2) the proxy data network used, 3) the target season, and 4) the spatial domain of the reconstruction. Estimates of hemispheric-mean temperature are formed through spatial averaging of reconstructed temperature patterns that are based on either the local calibration of proxy and instrumental data or a more elaborate multivariate climate field reconstruction approach. The experiments compare results based on the …

Minimum Energy Reliable Paths Using Unreliable Wireless Links, Qunfeng Dong

Computer Science Department Faculty Publication Series

No abstract provided.

Exploring E-Government Evolution: The Influence Of Systems Of Rules On Organizational Action, J. Ramon Gil-Garcia, Ignacio J. Martinez-Moyano

National Center for Digital Government

In general terms, e-government can be defined as the use of information and communication technologies in government settings. However, it is neither a homogeneous nor a static phenomenon. In recent years, empirical studies have identified two interesting dynamics in e-government evolution. First, e-government has evolved from its initial presence on the Internet to a more transactional and integrated approach. Second, at the aggregate level and as a general trend, national governments have started adding technological sophistication and have been followed by state and local governments. This paper attempts to explain these two dynamics in the evolution of e-government as a …

Chemical Manipulation Of High-Tc Ferromagnetism In Zno Diluted Magnetic Semiconductors, Kevin R. Kittilstved, D. R. Gamelin, N. S. Norberg

Kevin R. Kittilstved

We report the use of targeted p- and n-type chemical perturbations to manipulate high-TC ferromagnetism in Mn2+∶ZnO and Co2+∶ZnO in predictable and reproducible ways. We demonstrate a clear correlation between nitrogen and high-TC ferromagnetism for Mn2+∶ZnO and an inverse correlation for Co2+∶ZnO, both as predicted by recent theoretical models. These chemical perturbations reveal rich possibilities for exerting external control over high-TC spin ordering in diluted magnetic semiconductors.

Discovery Of A Primitive Damped Lyman Alpha Absorber Near An X-Ray Bright Galaxy Group In The Virgo Cluster, Todd M. Tripp, Edward B. Jenkins, David V. Bowen, Jason X. Prochaska, Bastien Aracil, Rajib Ganguly

Todd M. Tripp

We report the discovery of a low-redshift, sub-damped Ly_ absorber (DLA) in the outer periphery of the Virgo cluster near the X-ray bright NGC4261 galaxy group, in the direction of PG1216+069. We have obtained a new spectrum of PG1216+069 (zQSO = 0.3313) with the E140M echelle mode of the Space Telescope Imaging Spectrograph (STIS), and this spectrum reveals damped Ly_ absorption as well as O I, C II, Si II, and Fe II absorption lines at zabs = 0.00632. Notably, the absorber shows no evidence of highly-ionized gas: Si IV, C IV, and O VI are not signi_cantly detected at …

Site-Specific And Synergistic Stimulation Of Methylation On The Bacterial Chemotaxis Receptor Tsr By Serine And Chew, Robert Weis

Robert Weis

Background Specific glutamates in the methyl-accepting chemotaxis proteins (MCPs) of Escherichia coli are modified during sensory adaptation. Attractants that bind to MCPs are known to increase the rate of receptor modification, as with serine and the serine receptor (Tsr), which contributes to an increase in the steady-state (adapted) methylation level. However, MCPs form ternary complexes with two cytoplasmic signaling proteins, the kinase (CheA) and an adaptor protein (CheW), but their influences on receptor methylation are unknown. Here, the influence of CheW on the rate of Tsr methylation has been studied to identify contributions to the process of adaptation. Results Methyl …

Land Planning And Development Mitigation For Protecting Water Quality In The Great Lakes System: An Evaluation Of U.S. Approaches, Elizabeth Brabec, Peter Kumble

Elizabeth Brabec

A review of the land use/water quality interface of the Great Lakes system, and the monitoring programs in place. The paper reviews the weakness in the system and suggests opportunities for improvement.

Land Planning And Development Mitigation For Protecting Water Quality In The Great Lakes System: An Evaluation Of U.S. Approaches, Elizabeth Brabec, Peter Kumble

Landscape Architecture & Regional Planning Faculty Publication Series

A review of the land use/water quality interface of the Great Lakes system, and the monitoring programs in place. The paper reviews the weakness in the system and suggests opportunities for improvement.

The Connections Between Qso Absorption Systems And Galaxies: Low-Redshift Observations, Todd M. Tripp, David V. Bowen

Todd M. Tripp

Quasar absorption lines have long been recognised to be a sensitive probe of the abundances, physical conditions, and kinematics of gas in a wide variety of environments including low-density intergalactic regions that probably cannot be studied by any other means. While some pre-Hubble Space Telescope (HST) observations indicated that Mg II absorption lines arise in gaseous galactic halos with a large covering factor, many early QSO absorber studies were hampered by a lack of information about the context of the absorbers and their connections with galaxies. By providing access to crucial ultraviolet resonance lines at low redshifts, deployment of HST …

Low Regularity Solutions To A Gently Stochastic Nonlinear Wave Equation In Nonequilibrium Statistical Mechanics, L Rey-Bellet, Le Thomas

Luc Rey-Bellet

We consider a system of stochastic partial differential equations modeling heat conduction in a non-linear medium. We show global existence of solutions for the system in Sobolev spaces of low regularity, including spaces with norm beneath the energy norm. For the special case of thermal equilibrium, we also show the existence of an invariant measure (Gibbs state).

Isotropy Of The Early Universe From Cmb Anisotropies, Evan P. Donoghue, John Donoghue

John Donoghue

The acoustic peak in the CMB power spectrum is sensitive to causal processes and cosmological parameters in the early universe up to the time of last scattering. We provide limits on correlated spatial variations of the peak height and peak position and interpret these as constraints on the spatial variation of the cosmological parameters (baryon density, cold dark matter density and cosmological constant as well as the amplitude and tilt of the original fluctuations). We utilize recent work of Hansen, Banday and Gorski (HBG) who have studied the spatial isotropy of the power spectrum as measured by WMAP by performing …

Renormalization Of Initial Conditions And The Trans-Planckian Problem Of Inflation, Hael Collins, R. Holman

Physics Department Faculty Publication Series

No abstract provided.

Domain Walls Of Single-Component Bose–Einstein Condensates In External Potentials, Pg Kevrekidis

Mathematics and Statistics Department Faculty Publication Series

We demonstrate the possibility of creating domain walls described by a single component Gross–Pitaevskii equation with attractive interactions, in the presence of an optical–lattice potential. While it is found that the domain wall is unstable in an infinite system, we show that the external magnetic trap can stabilize it. Stable solutions also include “twisted” domain walls, as well as asymmetric solitons. The results apply as well to spatial solitons in planar nonlinear optical waveguides with transverse modulation of the refractive index.

Spontaneous Symmetry Breaking In Photonic Lattices: Theory And Experiment, Pg Kevrekidis

Mathematics and Statistics Department Faculty Publication Series

We examine an example of spontaneous symmetry breaking in a double-well waveguide with a symmetric potential. The ground state of the system beyond a critical power becomes asymmetric. The effect is illustrated numerically, and quantitatively analyzed via a Galerkin truncation that clearly shows the bifurcation from a symmetric to an asymmetric steady state. This phenomenon is also demonstrated experimentally when a probe beam is launched appropriately into an optically induced photonic lattice in a photorefractive material.

Umass Amherst Sustainability Plan, Brian Fitzpatrick

Sustainability Reports & Plans

This document is arranged in accordance with the guidelines specified in the Agency Sustainability Planning and Implementation Guide for the Massachusetts State Sustainability Program. The State Sustainability Program was established in July 2002 by Executive Order No. 438, which requires state agencies to “work diligently and expeditiously to develop and implement policies and procedures to promote environmentally sustainable practices.” The University of Massachusetts Amherst (UMA) is in the unique position to educate the next generation of the professional workforce in sustainable practices. The University feels that it is important for us to first have a firm understanding of sustainable development …

Equivariant Homology And K-Theory Of Affine Grassmannians And Toda Lattices, R Bezrukavnikov, M Finkelberg, I Mirkovic

Mathematics and Statistics Department Faculty Publication Series

For an almost simple complex algebraic group G with affine Grassmannian $\text{Gr}_G=G(\mathbb{C}(({\rm t})))/G(\mathbb{C}[[{\rm t}]])$, we consider the equivariant homology $H^{G(\mathbb{C}[[{\rm t}]])}(\text{Gr}_G)$ and K-theory $K^{G(\mathbb{C}[[{\rm t}]])}(\text{Gr}_G)$. They both have a commutative ring structure with respect to convolution. We identify the spectrum of homology ring with the universal group-algebra centralizer of the Langlands dual group $\check G$, and we relate the spectrum of K-homology ring to the universal group-group centralizer of G and of $\check G$. If we add the loop-rotation equivariance, we obtain a noncommutative deformation of the (K-)homology ring, and thus a Poisson structure on its …

Impact Of The Introduction Of Pneumococcal Conjugate Vaccine On Immunization Coverage Among Infants, Nancy D. Lin, Ken Kleinman, K Arnold Chan, Xian-Jie Yu, Eric K. France, Stanley Xu, Feifei Wei, John Mullooly, Jeanne Santoli, Tracey A. Lieu, Vaccine Safety Datalink Group

Public Health Department Faculty Publication Series

Background

The introduction of pneumococcal conjugate vaccine (PCV) to the U.S. recommended childhood immunization schedule in the year 2000 added three injections to the number of vaccinations a child is expected to receive during the first year of life. Surveys have suggested that the addition of PCV has led some immunization providers to move other routine childhood vaccinations to later ages, which could increase the possibility of missing these vaccines. The purpose of this study was to evaluate whether introduction of PCV affected immunization coverage for recommended childhood vaccinations among 13-month olds in four large provider groups.

Methods

In this …

Department Of Physics Newsletter: Spring 2005, Bob Krotkov, Gerry Peterson, Monroe Rabin, Hajime Sakai

Physics Newsletters

No abstract provided.