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2005

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Articles 1501 - 1530 of 5573

Full-Text Articles in Physical Sciences and Mathematics

Some Analogs Of Zariski's Theorem On Nodal Line Arrangements, A.D. Raza Choudary, Alexandru Dimca, Ştefan Papadima Jul 2005

Some Analogs Of Zariski's Theorem On Nodal Line Arrangements, A.D. Raza Choudary, Alexandru Dimca, Ştefan Papadima

Mathematics Faculty Scholarship

For line arrangements in P2 with nice combinatorics (in particular, for those which are nodal away the line at infinity), we prove that the combinatorics contains the same information as the fundamental group together with the meridianal basis of the abelianization. We consider higher dimensional analogs of the above situation. For these analogs, we give purely combinatorial complete descriptions of the following topological invariants (over an arbitrary field): the twisted homology of the complement, with arbitrary rank one coefficients; the homology of the associated Milnor fiber and Alexander cover, including monodromy actions; the coinvariants of the first higher non-trivial …

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Differentials In The Homological Homotopy Fixed Point Spectral Sequence, Robert R. Bruner, John Rognes Jul 2005

Differentials In The Homological Homotopy Fixed Point Spectral Sequence, Robert R. Bruner, John Rognes

Mathematics Faculty Research Publications

We analyze in homological terms the homotopy fixed point spectrum of a T–equivariant commutative S–algebra R. There is a homological homotopy fixed point spectral sequence with E^2_(s,t) = H^(−s)_(gp) (��;H_t(R;��_p)), converging conditionally to the continuous homology H^c_(s+t)(R^(h��);��_p) of the homotopy fixed point spectrum. We show that there are Dyer–Lashof operations β^ϵQ^i acting on this algebra spectral sequence, and that its differentials are completely determined by those originating on the vertical axis. More surprisingly, we show that for each class x in the E^(2r)–term of the spectral sequence there are 2r other classes in the E^(2r)–term (obtained mostly by Dyer–Lashof operations …

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G-Computation Estimation Of Nonparametric Causal Effects On Time-Dependent Mean Outcomes In Longitudinal Studies, Romain Neugebauer, Mark J. Van Der Laan Jul 2005

G-Computation Estimation Of Nonparametric Causal Effects On Time-Dependent Mean Outcomes In Longitudinal Studies, Romain Neugebauer, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Two approaches to Causal Inference based on Marginal Structural Models (MSM) have been proposed. They provide different representations of causal effects with distinct causal parameters. Initially, a parametric MSM approach to Causal Inference was developed: it relies on correct specification of a parametric MSM. Recently, a new approach based on nonparametric MSM was introduced. This later approach does not require the assumption of a correctly specified MSM and thus is more realistic if one believes that correct specification of a parametric MSM is unlikely in practice. However, this approach was described only for investigating causal effects on mean outcomes collected …

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Proving Secure Properties Of Cryptographic Protocols With Knowledge Based Approach, Xiaochun Cheng, Xiaoqi Ma, Maggie Xiaoyan Cheng, Scott C.-H. Huang Jul 2005

Proving Secure Properties Of Cryptographic Protocols With Knowledge Based Approach, Xiaochun Cheng, Xiaoqi Ma, Maggie Xiaoyan Cheng, Scott C.-H. Huang

Computer Science Faculty Research & Creative Works

Cryptographic protocols have been widely used to protect communications over insecure network environments. Existing cryptographic protocols usually contain flaws. To analyze these protocols and find potential flaws in them, the secure properties of them need be studied in depth. This paper attempts to provide a new framework to analyze and prove the secure properties in these protocols. A number of predicates and action functions are used to model the network communication environment. Domain rules are given to describe the transitions of principals' knowledge and belief states. An example of public key authentication protocols has been studied and analysed.

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The Webt Campaign To Observe Ao 0235+16 In The 2003-2004 Observing Season - Results From Radio-To-Optical Monitoring And Xmm-Newton Observations, Niall Smith, Et. Al. Jul 2005

The Webt Campaign To Observe Ao 0235+16 In The 2003-2004 Observing Season - Results From Radio-To-Optical Monitoring And Xmm-Newton Observations, Niall Smith, Et. Al.

Blackrock Castle Observatory Publications

A multiwavelength campaign to observe the BL Lac object AO 0235+16 () was set up by the Whole Earth Blazar Telescope (WEBT) collaboration during the observing seasons 2003–2004 and 2004–2005, involving radio, near-IR and optical photometric monitoring, VLBA monitoring, optical spectral monitoring, and three pointings by the XMM-Newton satellite. Here we report on the results of the first season, which involved the participation of 24 optical and near-IR telescopes and 4 radio telescopes, as well as the first XMM-Newton pointing, which occurred on January 18–19, 2004. Unpublished data from previous epochs were also collected (from 5 optical-NIR and 3 radio …

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Phase-Matching Optimization Of Laser High-Order Harmonics Generated In A Gas Cell, Julia Robin Miller Sutherland Jul 2005

Phase-Matching Optimization Of Laser High-Order Harmonics Generated In A Gas Cell, Julia Robin Miller Sutherland

Theses and Dissertations

Ten-millijoule, thirty-five femtosecond, 800 nm (~40 nm bandwidth) laser pulses are used to study high-order harmonic generation in helium- and neon-filled gas cells of various lengths. Harmonic orders in the range of 50 to 100 are investigated. A semi-infinite cell geometry produces brighter harmonics than cells of sub-centimeter length. In the semi-infinite geometry, the gas occupies the region from the focusing lens to a thin exit foil near the laser focus. Counter-propagating light is used to directly probe where the high harmonics are generated within the laser focus and to investigate phase matching. The phase matching under optimized harmonic generation …

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Exclusive Electroproduction Of Φ Mesons At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Guisti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini Jul 2005

Exclusive Electroproduction Of Φ Mesons At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Guisti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini

Faculty Publications

Exclusive electroproduction of φ mesons has been studied in e±p collisions at √s = 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb-1. The γ* p cross section is presented in the kinematic range 2 GeV2 < Q2 < 70 GeV2, 35 GeV < W < 145 GeV and t < 0.6 GeV2. The cross sections as functions of Q2, W, t and helicity angle θh are compared to cross sections for other vector mesons. The ratios R of the cross sections for longitudinally and transversely polarized virtual photons are presented as functions of Q2 and W. The data are also compared to predictions from theoretical models. © 2005 Elsevier B.V. All rights reserved.

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Mapping The Discrete Logarithm, Daniel R. Cloutier Jul 2005

Mapping The Discrete Logarithm, Daniel R. Cloutier

Mathematical Sciences Technical Reports (MSTR)

The discrete logarithm is a problem that surfaces frequently in the field of cryptog- raphy as a result of using the transformation ga mod n. This paper focuses on a prime modulus, p, for which it is shown that the basic structure of the functional graph is largely dependent on an interaction between g and p-1. In fact, there are precisely as many different functional graph structures as there are divisors of p-1. This paper extracts two of these structures, permutations and binary functional graphs. Estimates exist for the shape of a random permutation, but …

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Deconvolution Of The Co3O4(110) Fuchs–Kliewer Phonon Spectrum, E.M. Marsh, S.C. Petitto, G.S. Harbison, K.W. Wulser, Marjorie Langell Jul 2005

Deconvolution Of The Co3O4(110) Fuchs–Kliewer Phonon Spectrum, E.M. Marsh, S.C. Petitto, G.S. Harbison, K.W. Wulser, Marjorie Langell

Marjorie A. Langell Publications

The Fuchs–Kliewer phonon spectrum of single crystal Co3O4(110) has been treated with a Fourier transform log deconvolution method, which removes multiple scattering features from the single loss spectrum. Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) were first used to characterize the Co3O4 crystal establishing the cleanliness, composition, and order of the (110) surface. High resolution electron energy loss spectroscopy (HREELS) was then used to obtain the phonon spectrum for an incident electron energy of 3.77 eV. Due to the strong dipole cross section for the Fuchs–Kliewer phonon …

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Elemental T.G. Principles Of Relativistic T-Topos (Presheafification Of Matter, Space, And Time), Goro Kato Jul 2005

Elemental T.G. Principles Of Relativistic T-Topos (Presheafification Of Matter, Space, And Time), Goro Kato

Mathematics

We would like to solve the following problem: find a mathematical model formulating I) quantum entanglement, II) particle-wave duality, III) universal objects (ur-sub-Planck objects): to be defined in terms of direct or inverse limits (defined by universal mapping properties) giving microcosm behaviors of space-time so as to give the smooth macrocosm space-time, and IV) the “curved” space-time associated with particles with mass in microcosm consistent with the notion of a light cone in macrocosm. Problems I) and II) are treated in Kato G., Europhys. Lett., 68 (2004) 467. In this paper, we will focus on III) and IV). As …

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Localization Of Multiple Robots With Simple Sensors, Mike Peasgood, Christopher M. Clark, John Mcphee Jul 2005

Localization Of Multiple Robots With Simple Sensors, Mike Peasgood, Christopher M. Clark, John Mcphee

Computer Science and Software Engineering

This paper presents a distributed particle filter algorithm for localizing multiple mobile robots that are equipped only with low cost/low power sensors. This method is applicable to multi-micro robot systems, where size limitations restrict sensor selection (e.g. small infrared range finders). Localization of three robots in a known environment is conducted by combining measurements from a small number of simple range sensors with inter-robot distances obtained through an acoustic range finder system. The localization problem is formulated as estimating the global position and orientation of a single triangle, where corners of the triangle represent the positions of robots. The robot …

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Interactive Preferences And Decision-Theoretic Planning, Derek Williams, Kyle Bailey, Alex Dekhtyar, Judy Goldsmith, Beth Goldstein, Raphael Finkel, Joan Mazur Jul 2005

Interactive Preferences And Decision-Theoretic Planning, Derek Williams, Kyle Bailey, Alex Dekhtyar, Judy Goldsmith, Beth Goldstein, Raphael Finkel, Joan Mazur

Computer Science and Software Engineering

We introduce a suite of interlinked software tools for eliciting preferences, doing decision-theoretic planning, and displaying the plans. The software allows a user to walk through possible trajectories, adjust preferences, and compare potential trajectories. This paper focuses on the elicitation process, the plan display, and interactions between the two.

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Barry Saltzman And The Theory Of Climate, Kirk A. Maasch, R. J. Oglesby, A. Fournier Jul 2005

Barry Saltzman And The Theory Of Climate, Kirk A. Maasch, R. J. Oglesby, A. Fournier

Earth Science Faculty Scholarship

Barry Saltzman was a giant in the fields of meteorology and climate science. A leading figure in the study of weather and climate for over 40 yr, he has frequently been referred to as the "father of modern climate theory." Ahead of his time in many ways, Saltzman made significant contributions to our understanding of the general circulation and spectral energetics budget of the atmosphere, as well as climate change across a wide spectrum of time scales. In his endeavor to develop a unified theory of how the climate system works, lie played a role in the development of energy …

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Subdifferential Calculus In Asplund Generated Spaces, Marian Fabian, Philip D. Loewen, Boris S. Mordukhovich Jul 2005

Subdifferential Calculus In Asplund Generated Spaces, Marian Fabian, Philip D. Loewen, Boris S. Mordukhovich

Mathematics Research Reports

We extend the definition of the limiting Frechet subdifferential and the limiting Frechet normal cone from Asplund spaces to Asplund generated spaces. Then we prove a sum rule, a mean value theorem, and other statements for this concept.

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A Multi-Instrument Study Of The Helix Nebula Knots With The Hubble Space Telescope, C. R. O'Dell, W. J. Henney, Gary J. Ferland Jul 2005

A Multi-Instrument Study Of The Helix Nebula Knots With The Hubble Space Telescope, C. R. O'Dell, W. J. Henney, Gary J. Ferland

Physics and Astronomy Faculty Publications

We have conducted a combined observational and theoretical investigation of the ubiquitous knots in the Helix Nebula (NGC 7293). We have constructed a combined hydrodynamic + radiation model for the ionized portion of these knots and have accurately calculated a static model for their molecular regions. Imaging observations in optical emission lines were made with the Hubble Space Telescope's STIS, operating in a "slitless" mode, complemented by WFPC2 images in several of the same lines. The NICMOS camera was used to image the knots in H2. These observations, when combined with other studies of H2 and …

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Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Harold G. Marshall, Lubomira Burchardt Jul 2005

Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Harold G. Marshall, Lubomira Burchardt

Virginia Journal of Science

Phytoplankton composition and the range of seasonal patterns of abundance are presented for the tidal freshwater regions in two Virginia rivers based on data accumulated monthly from 1986 through 1999. Diatoms dominated the flora during spring, summer, and fall, whereas, other taxonomic categories were more representative when the river flow rates decreased, allowing for a more stable water system and increased residency time within this tidal region during summer and early fall. This summer/fall period was associated with increased water temperatures, higher productivity rates and chlorophyll levels, increased total phytoplankton abundance and species diversity. The major components of the summer …

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Taunton River Stewardship Plan: Taunton River Wild & Scenic River Study, Taunton Wild & Scenic River Study Committee, National Park Service, Northeast Region Jul 2005

Taunton River Stewardship Plan: Taunton River Wild & Scenic River Study, Taunton Wild & Scenic River Study Committee, National Park Service, Northeast Region

Reference Documents

No abstract provided.

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Western Rock Lobster Fishery - Ecological Risk Assessment 2005 Report., Mark Burgman Jul 2005

Western Rock Lobster Fishery - Ecological Risk Assessment 2005 Report., Mark Burgman

Fisheries management papers

The first two parts of the document provide background on the western rock lobster fishery and its governance. The third and fourth parts outline reporting requirements for the Ecologically Sustainable Development process and the specifics of the risk assessment process applied here. These sections are based substantially on reports written earlier by the Department of Fisheries and distributed to participants in the risk assessment process. They have been edited here to include only the details that were pertinent to this risk assessment. Parts 5, 6 and 7 provide the outcomes of the hazard elicitation workshop with stakeholders and the subsequent …

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A Semantic Template Based Designer For Semantic Web Processes, Ranjit Mulye, John A. Miller, Kunal Verma, Karthik Gomadam, Amit P. Sheth Jul 2005

A Semantic Template Based Designer For Semantic Web Processes, Ranjit Mulye, John A. Miller, Kunal Verma, Karthik Gomadam, Amit P. Sheth

Kno.e.sis Publications

The growing popularity of service oriented computing based on Web services standards is creating a need for paradigms to represent and design business processes. Significant work has been done in the representation aspects with regards to WSBPEL. However, design and modeling of business processes is still an open issue. In this paper, we present a novel designer for business processes, which allows for intuitive modeling of Web processes, as well as using a template based approach for semi-automatically integrating partners either at design time or at deployment time. This work has been done as part of the METEOR-S project, which …

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On Embedding Machine-Processable Semantics Into Documents, Krishnaprasad Thirunarayan Jul 2005

On Embedding Machine-Processable Semantics Into Documents, Krishnaprasad Thirunarayan

Kno.e.sis Publications

Most Web and legacy paper-based documents are available in human comprehensible text form, not readily accessible to or understood by computer programs. Here, we investigate an approach to amalgamate XML technology with programming languages for representational purposes that can enhance traceability, thereby facilitating semiautomatic extraction and update. Specifically, we propose a modular technique to embed machine-processable semantics into a text document with tabular data via annotations, resulting sometimes in ill-formed XML fragments, and evaluate this technique vis a vis document querying, manipulation, and integration. The ultimate aim is to be able to author and extract human-readable and machine-comprehensible parts of …

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The July 2003 Dakota Hailswaths: Creation, Characteristics, And Possible Impacts, Matthew D. Parker, Ian Ratcliffe, Geoffrey M. Henebry Jul 2005

The July 2003 Dakota Hailswaths: Creation, Characteristics, And Possible Impacts, Matthew D. Parker, Ian Ratcliffe, Geoffrey M. Henebry

School of Natural Resources: Faculty Publications

The authors investigate the meteorology associated with two elongated swaths of crop damage produced by severe hailstorms that crossed North Dakota and South Dakota on 4 July and 20 July 2003. These hailswaths, which were observed in a Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) image time series, each persisted for more than a month and were associated with local temperature increases, presumably owing to the enhanced Bowen ratio over dry, crop-free ground. This paper documents the creation and evolution of the convective storms that produced the hailswaths, and then presents evidence that devegetated hailswaths may impact …

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Seasonal And Interannual Varialbility In Evapotranspiration Of Native Tallgrass Prairie And Cultivated Wheat Ecosystems, By G.G. Burba, S.B. Verma, George G. Burba, Shashi B. Verma Jul 2005

Seasonal And Interannual Varialbility In Evapotranspiration Of Native Tallgrass Prairie And Cultivated Wheat Ecosystems, By G.G. Burba, S.B. Verma, George G. Burba, Shashi B. Verma

School of Natural Resources: Faculty Publications

No abstract provided.

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Spm Oxidation And Parallel Writing On Zirconium Nitride Thin Films, N. Farkas, J. R. Comer, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata Jul 2005

Spm Oxidation And Parallel Writing On Zirconium Nitride Thin Films, N. Farkas, J. R. Comer, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Systematic investigation of the SPM oxidation process of sputter-deposited ZrN thin films is reported. During the intrinsic part of the oxidation, the density of the oxide increases until the total oxide thickness is approximately twice the feature height. Further oxide growth is sustainable as the system undergoes plastic flow followed by delamination from the ZrN-silicon interface keeping the oxide density constant. ZrN exhibits superdiffusive oxidation kinetics in these single tip SPM studies. We extend this work to the fabrication of parallel oxide patterns 70 nm in height covering areas in the square centimeter range. This simple, quick, and well-controlled parallel …

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Keto-Carboxylic Acids In Carbonaceous Meteorites, Aliah C. Dugas Jul 2005

Keto-Carboxylic Acids In Carbonaceous Meteorites, Aliah C. Dugas

Electronic Dissertations and Theses

The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry and is generally used as references for organic compounds in extraterrestrial material. Among the classes of organic compounds found in the meteorite are amino acids, carboxylic acids, hydroxy acids, purines, and pyrimidines. Absent among today's critically important biological compounds reported in carbonaceous meteorites are keto acids, i.e., pyruvic acid, acetoacetic acid, and higher homologs. These compounds are key intermediates in such critical processes as glycolysis and the citric acid cycle. In this study several individual meteoritic keto acids were identified by gas chromatography-mass spectrometry (GC-MS). All compounds …

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Fire-Induced Albedo Change And Its Radative Forcing At The Surface In Northern Austrailia, Y. Jin, David P. Roy Jul 2005

Fire-Induced Albedo Change And Its Radative Forcing At The Surface In Northern Austrailia, Y. Jin, David P. Roy

GSCE Faculty Publications

This paper investigates the impact of fire on surface albedo and the associated radiative forcing over 56% of continental Australia encompassing the fire-prone northern tropical savanna. Fire-affected areas and albedos are derived for the 2003 fire season using daily Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data. Near-infrared and total shortwave albedos are observed to generally decrease after fire occurrence. Regionally, the total shortwave albedo drops by an average of 0.024, with increasing reductions as the dry season progresses and larger reductions in grasslands than woody savannas. These fire-induced albedo changes exert a positive forcing at the surface that increases …

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The 2004 Vaca Pateau Geoarcheology Expedition - Belize, Lee J. Florea, Beth Fratesi, Philip Reeder, Amber Yuellig Jul 2005

The 2004 Vaca Pateau Geoarcheology Expedition - Belize, Lee J. Florea, Beth Fratesi, Philip Reeder, Amber Yuellig

Lee J Florea, PhD, P.G.

No abstract provided.

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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 Jul 2005

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 …

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Update On Ethanol Processing Residue Properties, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan, James Julson, Padmanaban Krishnan Jul 2005

Update On Ethanol Processing Residue Properties, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan, James Julson, Padmanaban Krishnan

Kurt A. Rosentrater

The production of corn-based ethanol in the U.S. is dramatically increasing, and consequently so is the amount of byproduct materials generated from this processing sector. These coproduct streams are currently solely utilized as livestock feed, which is a route that provides ethanol processors with a substantial revenue source and significantly increases the profitability of the production process. With the construction and operation of many new plants in recent years, these residuals do, however, have much potential for value-added processing and utilization in other sectors as well. This option holds promise of economic benefit for corn processors, especially if the livestock …

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The Appearance, Apparent Speed, And Removal Of Optical Effects For Relativistically Moving Objects, Robert J. Deissler Jul 2005

The Appearance, Apparent Speed, And Removal Of Optical Effects For Relativistically Moving Objects, Robert J. Deissler

Robert J. Deissler

Because various parts of an object are different distances from an observer, and light takes a finite time to reach the observer, the appearance of a relativistically moving object will be very different from that given by the Lorentz contraction. We derive equations that can be applied to a photographic image so that the Lorentz contraction can still be observed. We also give equations that quantify the apparent deformation of the object and plots that show the apparent speed of the object as a function of time. In particular, as an object approaches, its apparent speed can be much greater …

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Symmetry Operator For The Maxwell Equations, Jose O. Andrade Jul 2005

Symmetry Operator For The Maxwell Equations, Jose O. Andrade

Graduate Student Papers (Physics)

In this work is shown that when the background space-time is type D solution of the Einstein vacuum equations with or without cosmological constant, a symmetry operator can be found for the Maxwell equations, as a consequence of that each component of the electromagnetic spinor satisfies a decoupled equation and that all the vacuum type D metrics admit a two index Killing spinor. Besides, the Maxwell equations are solved when the background space-time is the Carter A metric.

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