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2005

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Articles 5221 - 5250 of 5573

Full-Text Articles in Physical Sciences and Mathematics

Onset Conditions For Equatorial Spread F Determined During Equis Ii, D. L. Hysell, M. F. Larsen, C. M. Swenson, Aroh Barjatya, T. F. Wheeler, M. F. Sarango, Et.Al Jan 2005

Onset Conditions For Equatorial Spread F Determined During Equis Ii, D. L. Hysell, M. F. Larsen, C. M. Swenson, Aroh Barjatya, T. F. Wheeler, M. F. Sarango, Et.Al

Publications

An investigation into the dynamics and layer structure of the postsunset ionosphere prior to the onset of equatorial spread F (ESF) took place during the NASA EQUIS II campaign on Kwajalein Atoll on August 7 and 15, 2004. On both nights, an instrumented rocket measured plasma number density and vector electric fields to an apogee of about 450 km. Two chemical release rockets were launched both nights to measure lower thermospheric wind profiles. The Altair UHF/VHF radar was used to monitor coherent and incoherent scatter. In both experiments, strong plasma shear flow was detected. Periodic, patchy bottom-type scattering layers were …

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Transient Non-Linear Heat Conduction Solution By A Dual Reciprocity Boundary Element Method With An Effective Posteriori Error Estimator, Eduardo Divo, Alain J. Kassab Jan 2005

Transient Non-Linear Heat Conduction Solution By A Dual Reciprocity Boundary Element Method With An Effective Posteriori Error Estimator, Eduardo Divo, Alain J. Kassab

Publications

A Dual Reciprocity Boundary Element Method is formulated to solve non-linear heat conduction problems. The approach is based on using the Kirchhoff transform along with lagging of the effective non-linear thermal diffusivity. A posteriori error estimate is used to provide effective estimates of the temporal and spatial error. A numerical example is used to demonstrate the approach.

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Nédélec Spaces In Affine Coordinates, Jay Gopalakrishnan, Luis E. García-Castillo, Leszek Demkowicz Jan 2005

Nédélec Spaces In Affine Coordinates, Jay Gopalakrishnan, Luis E. García-Castillo, Leszek Demkowicz

Mathematics and Statistics Faculty Publications and Presentations

In this note, we provide a conveniently implementable basis for simplicial Nédélec spaces of any order in any space dimension. The main feature of the basis is that it is expressed solely in terms of the barycentric coordinates of the simplex.

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Modeling The Evolution Of Inhomogeneities, Marek Elźanowski, Serge Preston Jan 2005

Modeling The Evolution Of Inhomogeneities, Marek Elźanowski, Serge Preston

Mathematics and Statistics Faculty Publications and Presentations

A model of an anelastic evolution law of a defective continuum is discussed, emphasizing the role of the Clausius-Duhem inequality in selecting admissible processes.

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New Approaches To Understanding The Mechanics Of Burgess Shale-Type Deposits: From The Micron Scale To The Global Picture, Robert Gaines, Mary L. Droser Jan 2005

New Approaches To Understanding The Mechanics Of Burgess Shale-Type Deposits: From The Micron Scale To The Global Picture, Robert Gaines, Mary L. Droser

Pomona Faculty Publications and Research

Cambrian Burgess Shale-type (BST) deposits are among the most significant deposits for understanding the “Cambrian explosion” because they contain the fossilized tissues of nonmineralized organisms and provide a substantially different window on the radiation of the Metazoa than is afforded by the more “typical” fossil record of skeletal parts of biomineralized organisms. Despite nearly a century of research, BST deposits remain poorly investigated as sedimentologic entities largely because they comprise fine-grained mudrocks. Here,we describe a new, integrative approach to understanding a single BST deposit, the middle Cambrian Wheeler Formation of Utah, which reveals a dynamic interplay of paleoenvironmental, paleoecologic, and …

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The Ims New Researchers' Survival Guide, Naomi Altman, David Banks, Janis Hardwick, Kathryn Roeder, Peter Craigmile, Johanna S. Hardin, Mayetri Gupta Jan 2005

The Ims New Researchers' Survival Guide, Naomi Altman, David Banks, Janis Hardwick, Kathryn Roeder, Peter Craigmile, Johanna S. Hardin, Mayetri Gupta

Pomona Faculty Publications and Research

Statistics is a wonderfully diverse profession and graduate students making career choices have many options — especially in light of the dearth of students moving into the statistical sciences today. The three main career paths at the PhD level are in academics, industry/business and government. Each of these job types offers its own mix of intellectual challenges, financial reward, pressure and security. How a new researcher selects (or is selected by) a specific occupation in the statistical sciences sometimes seems more a function of luck than of conscious decision making. This consideration was one of the first concerns addressed by …

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Development And Implementation Of An E-Commerce Database Application To Support St. Paul A.M.E. Church, Montez A. Toney Jan 2005

Development And Implementation Of An E-Commerce Database Application To Support St. Paul A.M.E. Church, Montez A. Toney

Regis University Student Publications (comprehensive collection)

This project proposal is an endeavor to implement modern technology into long-standing processes at St. Paul African Methodist Episcopal (A.M.E.) Church. The modern technology is e-Commerce. The long-standing process is the method of paying tithes in a collection plate and ordering books, tapes etc. through a designated individual or committee. The goal of this project is to research realistic solutions and develop a practical plan to implement the project. Throughout this process, special care is taken to select resources that are moderately priced and straightforward to implement, this is to increase the probability of a successful implementation.

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Stable Motions Of Vehicle Formations, Anca Williams, Gerardo Lafferriere, J. J. P. Veerman Jan 2005

Stable Motions Of Vehicle Formations, Anca Williams, Gerardo Lafferriere, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We investigate stable maneuvers for a group of autonomous vehicles while moving in formation. The allowed decentralized feeback laws are factored through the Laplacian matrix of the communication graph. We show that such laws allow for stable circular or elliptical motions for certain vehicle dynamics. We find necessary and sufficient conditions on the feedback gains and the dynamic parameters for convergence to formation. In particular, we prove that for undirected graphs there exist feedback gains that stabilize rotational (or elliptical) motions of arbitrary radius (or eceentricity). In the directed graph case we provide necessary and sufficient conditions on the curvature …

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A Note On Lattice Chains And Delannoy Numbers, John S. Caughman Iv, Clifford R. Haithcock, J. J. P. Veerman Jan 2005

A Note On Lattice Chains And Delannoy Numbers, John S. Caughman Iv, Clifford R. Haithcock, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

Fix nonnegative integers n1,…,nd and let L denote the lattice of integer points (a1,…,ad)∈Zd satisfying 0⩽ai⩽ni for 1⩽i⩽d. Let L be partially ordered by the usual dominance ordering. In this paper we offer combinatorial derivations of a number of results concerning chains in L. In particular, the results obtained are established without recourse to generating functions or recurrence relations. We begin with an elementary derivation of the number of chains in L of a given size, from which one can deduce the classical expression for the total number …

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French Lessons: F.P. Baker, American Forestry, And The 1878 Paris Universal Exposition, Char Miller Jan 2005

French Lessons: F.P. Baker, American Forestry, And The 1878 Paris Universal Exposition, Char Miller

Pomona Faculty Publications and Research

Although he never became a forester, F. P. Baker did much to advance the profession’s cause. Its potential became clear to him while serving as a U.S. Commissioner to the 1878 Paris Exposition, during which he reported on European forestry, its scientific methods and political meaning. Returning home, he was inspired to advance forestry in America.

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Amateur Hour: Nathaniel H. Egleston And Professional Forestry In Post-Civil War America, Char Miller Jan 2005

Amateur Hour: Nathaniel H. Egleston And Professional Forestry In Post-Civil War America, Char Miller

Pomona Faculty Publications and Research

Nathaniel Egleston, the second head of the U.S. Division of Forestry (1883–1886), is a forgotten figure in the history of early American forestry. The one-time minister became a tireless advocate for trees in the post-Civil War era, writing innumerable and well-received essays and pamphlets. But his enthusiasm did not translate into administrative success, and he was replaced by Bernard Fernow, who in turn was succeeded by Gifford Pinchot; the pair’s scientific training signaled the professionalization of American forestry.

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The Backward Shift On Dirichlet-Type Spaces, Stephan Ramon Garcia Jan 2005

The Backward Shift On Dirichlet-Type Spaces, Stephan Ramon Garcia

Pomona Faculty Publications and Research

We study the backward shift operator on Hilbert spaces H_α (for α ≥ 0) which are norm equivalent to the Dirichlet-type spaces D_α. Although these operators are unitarily equivalent to the adjoints of the forward shift operator on certain weighted Bergman spaces, our approach is direct and completely independent of the standard Cauchy duality. We employ only the classical Hardy space theory and an elementary formula expressing the inner product on H_α in terms of a weighted superposition of backward shifts.

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A *-Closed Subalgebra Of The Smirnov Class, Stephan Ramon Garcia Jan 2005

A *-Closed Subalgebra Of The Smirnov Class, Stephan Ramon Garcia

Pomona Faculty Publications and Research

We study real Smirnov functions and investigate a certain *-closed subalgebra of the Smirnov class N^+ containing them. Motivated by a result of Aleksandrov, we provide an explicit representation for the space H^p ∩ H^p [overscore over the second H^p]. This leads to a natural analog of the Riesz projection on a certain quotient space of L^p for p ϵ (0, 1). We also study a Herglotz-like integral transform for singular measures on the unit circle ∂D.

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Microarray Data From A Statistician’S Point Of View, Johanna S. Hardin Jan 2005

Microarray Data From A Statistician’S Point Of View, Johanna S. Hardin

Pomona Faculty Publications and Research

No abstract provided.

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Inner Matrices And Darlington Synthesis, Stephan Ramon Garcia Jan 2005

Inner Matrices And Darlington Synthesis, Stephan Ramon Garcia

Pomona Faculty Publications and Research

We describe and parameterize the solutions of the scalar valued Darlington synthesis problem. In the case of rational data we derive a simple procedure for producing all possible solutions.

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Portable Emission Measurements Of Snowcoaches And Snowmobiles In Yellowstone National Park (Presentation), John D. Ray, Gary A. Bishop Jan 2005

Portable Emission Measurements Of Snowcoaches And Snowmobiles In Yellowstone National Park (Presentation), John D. Ray, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

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Broad-Scale Non-Indigenous Species Monitoring Along The West Coast In National Marine Sanctuaries And National Estuarine Research Reserves, Catherine E. De Rivera, Greg Ruiz, Jeff Crooks, Kerstin Wasson, Steve Lonhart, Paul Fofonoff, Brian Steves, Steven S. Rumrill, Mary Sue Brancato, Scott Pegau, Doug Bulthuis, Rikke Kvist Preisler, Carl Schoch, Ed Bowlby, Andrew Devogelaere, Maurice Crawford, Steve Gittings, Anson Hines, Lynn Takata, Kristen Larson, Tami Huber, Anne Marie Leyman, Esther Collinetti, Tiffany Pascot, Suzanne Shull, Mary Anderson, Sue Powell Jan 2005

Broad-Scale Non-Indigenous Species Monitoring Along The West Coast In National Marine Sanctuaries And National Estuarine Research Reserves, Catherine E. De Rivera, Greg Ruiz, Jeff Crooks, Kerstin Wasson, Steve Lonhart, Paul Fofonoff, Brian Steves, Steven S. Rumrill, Mary Sue Brancato, Scott Pegau, Doug Bulthuis, Rikke Kvist Preisler, Carl Schoch, Ed Bowlby, Andrew Devogelaere, Maurice Crawford, Steve Gittings, Anson Hines, Lynn Takata, Kristen Larson, Tami Huber, Anne Marie Leyman, Esther Collinetti, Tiffany Pascot, Suzanne Shull, Mary Anderson, Sue Powell

Environmental Science and Management Faculty Publications and Presentations

Nonindigenous species have caused substantial environmental and economic damage to coastal areas. Moreover, the extent and impacts of nonindigenous species are increasing over time. To develop predictive models and to identify which areas should be targeted for impact mitigation or early detection, we need a basic foundation of knowledge about the spatial and temporal patterns of invasions. This project was developed because we lacked the necessary data to rigorously evaluate the patterns of coastal invasions. This collaborative project, between the Smithsonian Environmental Research Center, the National Estuarine Research Reserve System (NERRS) and the National Marine Sanctuary Program (NMSP), established a …

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A Map On The Space Of Rational Functions, G. Boros, J. Little, V. Moll, Edward Mosteig, R. Stanley Jan 2005

A Map On The Space Of Rational Functions, G. Boros, J. Little, V. Moll, Edward Mosteig, R. Stanley

Mathematics, Statistics and Data Science Faculty Works

We describe dynamical properties of a map defined on the space of rational functions. The fixed points of F are classified and the long time behavior of a subclass is described in terms of Eulerian polynomials.

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Derived Categories And The Analytic Approach To General Reciprocity Laws. Part I, Michael Berg Jan 2005

Derived Categories And The Analytic Approach To General Reciprocity Laws. Part I, Michael Berg

Mathematics, Statistics and Data Science Faculty Works

We reformulate Hecke's open problem of 1923, regarding the Fourier-analytic proof of higher reciprocity laws, as a theorem about morphisms involving stratified topological spaces. We achieve this by placing Kubota's formulations of n-Hilbert reciprocity in a new topological context, suited to the introduction of derived categories of sheaf complexes. Subsequently, we begin to investigate conditions on associated sheaves and a derived category of sheaf complexes specifically designed for an attack on Hecke's eighty-year-old challenge.

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Commensurability Classes Of Twist Knots, Jim Hoste, Patrick D. Shanahan Jan 2005

Commensurability Classes Of Twist Knots, Jim Hoste, Patrick D. Shanahan

Mathematics, Statistics and Data Science Faculty Works

In this paper we prove that if MK is the complement of a non-fibered twist knot K in S3, then MK is not commensurable to a fibered knot complement in a Z/2Z-homology sphere. To prove this result we derive a recursive description of the character variety of twist knots and then prove that a commensurability criterion developed by D. Calegari and N. Dunfield is satisfied for these varieties. In addition, we partially extend our results to a second infinite family of 2-bridge knots.

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From Loop Groups To 2-Groups, John C. Baez, Danny Stevenson, Alissa S. Crans, Urs Schreiber Jan 2005

From Loop Groups To 2-Groups, John C. Baez, Danny Stevenson, Alissa S. Crans, Urs Schreiber

Mathematics, Statistics and Data Science Faculty Works

We describe an interesting relation between Lie 2-algebras, the Kac-Moody central extensions of loop groups, and the group String(n). A Lie 2-algebra is a categorified version of a Lie algebra where the Jacobi identity holds up to a natural isomorphism called the "Jacobiator". Similarly, a Lie 2-group is a categorified version of a Lie group. If G is a simply-connected compact simple Lie group, there is a 1-parameter family of Lie 2-algebras g_k each having Lie(G) as its Lie algebra of objects, but with a Jacobiator built from the canonical 3-form on G. There appears to be no Lie 2-group …

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Reproductive Attributes Of Polynoid Polychaetes From Hydrothermal Vents On The East Pacific Rise, Jessica Lynn Wallace Jan 2005

Reproductive Attributes Of Polynoid Polychaetes From Hydrothermal Vents On The East Pacific Rise, Jessica Lynn Wallace

Dissertations, Theses, and Masters Projects

No abstract provided.

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Positive Solutions For A Fourth Order Boundary Value Problem, Bo Yang Jan 2005

Positive Solutions For A Fourth Order Boundary Value Problem, Bo Yang

Faculty Articles

We consider a boundary value problem for the beam equation, in which the boundary conditions mean that the beam is embedded at one end and free at the other end. Some new estimates to the positive solutions to the boundary value problem are obtained. Some sufficient conditions for the existence of at least one positive solution for the boundary value problem are established. An example is given at the end of the paper to illustrate the main results.

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2005 Plant Community Field Surveys In Western Nebraska, Robert F. Steinauer Jan 2005

2005 Plant Community Field Surveys In Western Nebraska, Robert F. Steinauer

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

These surveys were undertaken to provide biological data for the Nebraska Game and Parks Commission’s (NGPC) Nebraska Natural Legacy Action Plan. The specific intent was to identify, map, and give quality rankings to large blocks of privately-owned native plant communities within the survey area. In 2005, the surveys focused on Keith, Deuel, Cheyenne, Kimball, Banner, and Scotts Bluff counties, Sioux, Dawes and Sheridan counties north of the Pine Ridge, and Garden County south of the North Platte River.

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Burial Of Terrestrial Organic Matter In Marine Sediments: A Re-Assessment, David J. Burdige Jan 2005

Burial Of Terrestrial Organic Matter In Marine Sediments: A Re-Assessment, David J. Burdige

OES Faculty Publications

Calculations based on recent observations indicate that approximately one third of the organic matter presently being buried in marine sediments may be of terrestrial origin, with the majority of this terrestrial organic matter (TOM) burial occurring in muddy, deltaic sediments. These calculations further suggest that the remineralization of terrestrial organic matter in the oceans is also much less efficient than that of marine organic matter. These two underappreciated observations have important implications in terms of our understanding of the controls on the global carbon cycle. From a paleoceanographic perspective, the results presented here also suggest that changes in TOM burial …

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The Effect Of Growth Rate, Phosphorus Concentration, And Temperature On N-2 Fixation, Carbon Fixation, And Nitrogen Release In Continuous Cultures Of Trichodesmium Ims101, Margaret R. Mulholland, Peter W. Bernhardt Jan 2005

The Effect Of Growth Rate, Phosphorus Concentration, And Temperature On N-2 Fixation, Carbon Fixation, And Nitrogen Release In Continuous Cultures Of Trichodesmium Ims101, Margaret R. Mulholland, Peter W. Bernhardt

OES Faculty Publications

With the use of continuous culture systems, rates of dinitrogen (N2) and carbon (C) fixation and nitrogen (N)- and C-based doubling times were assessed in Trichodesmium IMS101 growing exponentially at steady state dilution rates of 0.10, 0.20, and 0.33 d-1 (doubling times of 10, 5, and 3 d - within the range reported for natural populations). Rates of C fixation, N2 fixation, and N release were examined in replicate culture systems with several techniques. Biomass-specific C uptake varied little with population doubling time, but N2 fixation and N release varied markedly among treatments. Total daily …

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Demonstration Of Toxicity To Fish And To Mammalian Cells By Pfiesteria Species: Comparison Of Assay Methods And Strains, Joann M. Burkholder, Andrew S. Gordon, Peter D. Moeller, J. Mac Law, Kathryn J. Coyne, Alan J. Lewitus, John S. Ramsdell, Harold G. Marshall, Nora J. Deamer, S. Craig Cary, Jason W. Kempton, Steven L. Morton, Parke A. Rublee Jan 2005

Demonstration Of Toxicity To Fish And To Mammalian Cells By Pfiesteria Species: Comparison Of Assay Methods And Strains, Joann M. Burkholder, Andrew S. Gordon, Peter D. Moeller, J. Mac Law, Kathryn J. Coyne, Alan J. Lewitus, John S. Ramsdell, Harold G. Marshall, Nora J. Deamer, S. Craig Cary, Jason W. Kempton, Steven L. Morton, Parke A. Rublee

Biological Sciences Faculty Publications

Toxicity and its detection in the dinoflagellate fish predators Pfiesteria piscicida and Pfiesteria shumwayae depend on the strain and the use of reliable assays. Two assays, standardized fish bioassays (SFBs) with juvenile fish and fish microassays (FMAs) with larval fish, were compared for their utility to detect toxic Pfiesteria. The comparison included strains with confirmed toxicity, negative controls (noninducible Pfiesteria strains and a related nontoxic cryptoperidiniopsoid dinoflagellate), and P. shumwayae strain CCMP2089, which previously had been reported as nontoxic. SFBs, standardized by using toxic Pfiesteria (coupled with tests confirming Pfiesteria toxin) and conditions conducive to toxicity expression, reliably detected …

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Comparison Of Phytoplankton And Autotrophic Picoplankton Populations Over A 24-Hour Period From A Pond's Surface And Subsurface Waters, Harold G. Marshall, Lubomira Burchardt, Elżbieta Wilk-Woźniak Jan 2005

Comparison Of Phytoplankton And Autotrophic Picoplankton Populations Over A 24-Hour Period From A Pond's Surface And Subsurface Waters, Harold G. Marshall, Lubomira Burchardt, Elżbieta Wilk-Woźniak

Biological Sciences Faculty Publications

Phytoplankton abundance and composition relationships within the surface layer changed over short time periods (4-6 hours) in comparison with more constant associations at 2 cm below the surface. Both strata had a diverse algal flora (>50 taxa), but no distinct neuston assemblage characterized the surface layer algal composition over the 24-hour study. The similarity between the two strata indicated the floral composition of the surface layer came from the water column algae below the surface. Chlorophytes, diatoms, cyanobacteria, and cryptophytes represented the most abundant algal categories for both strata with a total mean phytoplankton abundance of 3,566 cells ml …

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Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus In Virginia Tidal Marshes, Christopher P. Bloch, Robert K. Rose Jan 2005

Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus In Virginia Tidal Marshes, Christopher P. Bloch, Robert K. Rose

Biological Sciences Faculty Publications

Oryzomys palustris (marsh rice rat) and Microtus pennsylvanicus (meadow vole) cohabit coastal marshes in the mid-Atlantic US. Both were live-trapped for 23 months at two tidal marsh sites in Virginia to assess their demography near the margins of their distributions. In the presence of dense vegetation, population dynamics of the two species were seasonal and positively correlated, with densities declining through the winter. At the more sparsely vegetated site, densities of both species were lower, and densities of M. pennsylvanicus were negatively correlated with those of O. palustris. Patterns of reproduction differed between the species. O. palustris was reproductively …

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The 2003 Boumerdes, Algeria Earthquake: Regional Moment Tensor Analysis, Jochen Braunmiller, Fabrizio Bernardi Jan 2005

The 2003 Boumerdes, Algeria Earthquake: Regional Moment Tensor Analysis, Jochen Braunmiller, Fabrizio Bernardi

School of Geosciences Faculty and Staff Publications

We used regional broadband seismograms to determine seismic moment tensors for the destructive May 21, 2003 Boumerdes (Algeria) Mw = 7.0 earthquake and its larger aftershocks. Fully automatic inversions using near-real time data provided solutions for seven Mw ≥ 4.7 events within 90 minutes after event occurrence. After adding off-line data, we manually obtained 30 solutions (Mw ≥ 3.8) from May 2003 to January 2004. All have shallow source depths (6–21 km). The median P-axis orientation (338°) of 24 thrust and four strike-slip events is consistent with Africa-Eurasia plate motion (330°). The main shock hypocenter at 8–10 …

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