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2004

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Articles 811 - 840 of 4447

Full-Text Articles in Physical Sciences and Mathematics

Influence Of Lithophysae Geometry And Distribution On Mechanical Properties Of Topopah Spring Tuff, Mohammad Shahidul Islam, Justin Fenton, Moses Karakouzian, Jaime Gonzalez, Amy J. Smiecinski, Raymond E. Keeler Sep 2004

Influence Of Lithophysae Geometry And Distribution On Mechanical Properties Of Topopah Spring Tuff, Mohammad Shahidul Islam, Justin Fenton, Moses Karakouzian, Jaime Gonzalez, Amy J. Smiecinski, Raymond E. Keeler

Publications (YM)

The current Site Recommendation study for the proposed high level nuclear waste repository at Yucca Mountain locates the repository emplacement drifts approximately 81% within the lower lithophysal unit of the Topopah Springs Formation (Tptpll), 4% within the upper lithophysal unit of the Topopah Springs Formation (Tptpul), and roughly 15% within the middle, non-lithophysal unit (Tptpmn) of the same formation. A major geomechanical issue facing the Yucca Mountain Project is to understand the thermomechanical behavior of lithophysal tuff, which comprises roughly 85% of the repository host rock.

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Simulations Of Resonant Alfvén Waves Generated By Artificial Hf Heating Of The Auroral Ionosphere, D Pokhotelov, W Lotko, A V. Streltsov Sep 2004

Simulations Of Resonant Alfvén Waves Generated By Artificial Hf Heating Of The Auroral Ionosphere, D Pokhotelov, W Lotko, A V. Streltsov

Dartmouth Scholarship

Numerical two-dimensional two-fluid MHD sim- ulations of dynamic magnetosphere-ionosphere (MI) cou- pling have been performed to model the effects imposed on the auroral ionosphere by a powerful HF radio wave trans- mitter. The simulations demonstrate that modifications of the ionospheric plasma temperature and recombination due to artificial heating may trigger the ionospheric feedback in- stability when the coupled MI system is close to the state of marginal stability. The linear dispersion analysis of MI coupling has been performed to find the favorable conditions for marginal stability of the system. The development of the ionospheric feedback instability leads to the generation …

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Stable Isotopes(Δ18 O, Δ13 C) Of Mollusk Shells In Environmental Interpretations; An Example From Si̇nop Miocene Succession (Northern Turkey), Baki Varol Sep 2004

Stable Isotopes(Δ18 O, Δ13 C) Of Mollusk Shells In Environmental Interpretations; An Example From Si̇nop Miocene Succession (Northern Turkey), Baki Varol

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Halide Recognition Through Diagnostic “Anion–Π” Interactions: Molecular Complexes Of CL−, Br−, And I− With Olefinic And Aromatic Π Receptors, Yaroslav S. Rosokha, Sergey Lindeman, Sergiy V. Rosokha, Jay K. Kochi Sep 2004

Halide Recognition Through Diagnostic “Anion–Π” Interactions: Molecular Complexes Of CL−, Br−, And I− With Olefinic And Aromatic Π Receptors, Yaroslav S. Rosokha, Sergey Lindeman, Sergiy V. Rosokha, Jay K. Kochi

Chemistry Faculty Research and Publications

Intense colorations and new charge-transfer absorption bands are observed upon addition of a halide (Cl−, Br−, I−) to neutral organic π acceptors with electron-deficient olefinic and aromatic centers. These phenomena results from noncovalent anion–π interactions (shown schematically), which were confirmed by X-ray crystallography.

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Exclusive Electroproduction Of J/Ψ Mesons At-Hera, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, 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. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, L. Rinaldi Sep 2004

Exclusive Electroproduction Of J/Ψ Mesons At-Hera, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, 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. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, L. Rinaldi

Faculty Publications

The exclusive electroproduction of J/ψ mesons, ep→epJ/ψ, has been studied with the ZEUS detector at HERA for virtualities of the exchanged photon in the ranges 0.15

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Sedimentary Infill And Geological Evolution Of Çameli̇ Neogene Basin, Deni̇zli̇-Sw Turkey, Mehmet Cihat Alçi̇çek, Nizamettin Kazanci, Mehmet Özkul, Şevket Şen Sep 2004

Sedimentary Infill And Geological Evolution Of Çameli̇ Neogene Basin, Deni̇zli̇-Sw Turkey, Mehmet Cihat Alçi̇çek, Nizamettin Kazanci, Mehmet Özkul, Şevket Şen

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Non-Destructive Testing Of Thermal Resistances For A Single Inclusion In A 2-Dimensional Domain, Nicholas Christian, Mathew A. Johnson Sep 2004

Non-Destructive Testing Of Thermal Resistances For A Single Inclusion In A 2-Dimensional Domain, Nicholas Christian, Mathew A. Johnson

Mathematical Sciences Technical Reports (MSTR)

In this paper we examine the inverse problem of determining the amount of corrosion/disbonding which has occurred on the boundary of a single circular (or nearly circular) inclusion D in a two dimensional domain W using Cauchy data for the steady-state heat equation. We develop an algorithm for reconsructing a function which qunatifies the level of corrosion/disbonding at each point in ¶W. We also address the issue of well-posedness and develop a simple regularization scheme. Then we provide several numerical examples. We shall show a simple procedure for recovering the center of D assuming that the boundary of W and …

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Middle - Upper Miocene Stratigraphy Of Çanakkale, Nw Turkey, Eşref Atabey, Ayhan Ilgar, Alper Sakitaş Sep 2004

Middle - Upper Miocene Stratigraphy Of Çanakkale, Nw Turkey, Eşref Atabey, Ayhan Ilgar, Alper Sakitaş

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Lattice Supersymmetry Via Twisting, Simon Catterall Sep 2004

Lattice Supersymmetry Via Twisting, Simon Catterall

Physics - All Scholarship

We describe how the usual supercharges of extended supersymmetry may be {\it twisted} to produce a BRST-like supercharge Q. The usual supersymmetry algebra is then replaced by a twisted algebra and the action of the twisted theory is shown to be generically Q-exact. In flat space the twisting procedure can be regarded as a change of variables carrying no physical significance. However, the twisted theories can often be transferred to the lattice while preserving the twisted supersymmetry. As an example we construct a lattice version of the two-dimensional supersymmetric sigma model

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The Control Of The Forced - Regression, Transgression And Sediment Supply On The Sedimentological And Sequence Stratigraphical Development Of The Basin Margin Depositional Systems; Ermenek Basin, Middle Taurides, Ayhan Ilgar Sep 2004

The Control Of The Forced - Regression, Transgression And Sediment Supply On The Sedimentological And Sequence Stratigraphical Development Of The Basin Margin Depositional Systems; Ermenek Basin, Middle Taurides, Ayhan Ilgar

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Active Slumping Offshore Amasra (Southwest Black Sea) And Its Relation With Regional Tectonics, İsmail Kuşçu, Jeffrey R. Parke, Robert S. White, Dan Mckenzle, Gareth A. Anderson, Timothy A. Minshull, Naci Görür, A.M. Celal Şengör Sep 2004

Active Slumping Offshore Amasra (Southwest Black Sea) And Its Relation With Regional Tectonics, İsmail Kuşçu, Jeffrey R. Parke, Robert S. White, Dan Mckenzle, Gareth A. Anderson, Timothy A. Minshull, Naci Görür, A.M. Celal Şengör

Bulletin of the Mineral Research and Exploration

No abstract provided.

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Estimating A Survival Distribution With Current Status Data And High-Dimensional Covariates, Mark J. Van Der Laan, Aad Van Der Vaart Sep 2004

Estimating A Survival Distribution With Current Status Data And High-Dimensional Covariates, Mark J. Van Der Laan, Aad Van Der Vaart

U.C. Berkeley Division of Biostatistics Working Paper Series

We consider the inverse problem of estimating a survival distribution when the survival times are only observed to be in one of the intervals of a random bisection of the time axis. We are particularly interested in the case that high-dimensional and/or time-dependent covariates are available, and/or the survival events and censoring times are only conditionally independent given the covariate process. The method of estimation consists of regularizing the survival distribution by taking the primitive function or smoothing, estimating the regularized parameter by using estimating equations, and finally recovering an estimator for the parameter of interest.

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Estimation Of Treatment Effects In Randomized Trials With Noncompliance And A Dichotomous Outcome , Mark J. Van Der Laan, Alan E. Hubbard, Nicholas P. Jewell Sep 2004

Estimation Of Treatment Effects In Randomized Trials With Noncompliance And A Dichotomous Outcome , Mark J. Van Der Laan, Alan E. Hubbard, Nicholas P. Jewell

U.C. Berkeley Division of Biostatistics Working Paper Series

We propose a class of estimators of the treatment effect on a dichotomous outcome among the treated subjects within covariate and treatment arm strata in randomized trials with non-compliance. Recent articles by Vansteelandt and Goethebeur (2003) and Robins and Rotnitzky (2004) have presented consistent and asymptotically linear estimators of a causal odds ratio, which rely, beyond correct specification of a model for the causal odds ratio, on a correctly specified model for a potentially high dimensional nuisance parameter. In this article we propose consistent, asymptotically linear and locally efficient estimators of a causal relative risk and a new parameter -- …

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Spin Mass Of An Electron Liquid, Zhixin Qian, Giovanni Vignale, D C. Marinescu Sep 2004

Spin Mass Of An Electron Liquid, Zhixin Qian, Giovanni Vignale, D C. Marinescu

Publications

We show that in order to calculate correctly the spin current carried by a quasiparticle in an electron liquid one must use an effective ‘‘spin mass’’ ms that is larger than both the band mass mb, which determines the charge current, and the quasiparticle effective mass m, which determines the heat capacity. We present two independent estimates of the spin mass enhancement, ms=mb, in two- and three-dimensional electron liquids, based on (i) previously calculated values of the Landau parameters and (ii) a recent theory of the dynamical local field factor in the spin channel. Both methods yield a significant spin …

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Correction To ‘‘A Concept Of Maximum Stream Depletion Rate For Leaky Aquifers In Alluvial Valleys" By Vitaly A. Zlotnik, Vitaly A. Zlotnik Sep 2004

Correction To ‘‘A Concept Of Maximum Stream Depletion Rate For Leaky Aquifers In Alluvial Valleys" By Vitaly A. Zlotnik, Vitaly A. Zlotnik

Department of Earth and Atmospheric Sciences: Faculty Publications

In the paper ‘‘A concept of maximum stream depletion rate for leaky aquifers in alluvial valleys’’ by Vitaly A. Zlotnik (Water Resources Research, 40(6), W06507, doi:10.1029/2003WR002932, 2004), equations (24), (25), (A11), and (A12) were published with typographical errors. The correct equations are published below.

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Utilizing Learning Styles For Interactive Tutorials, Magnus Aase, Franz J. Kurfess Sep 2004

Utilizing Learning Styles For Interactive Tutorials, Magnus Aase, Franz J. Kurfess

Computer Science and Software Engineering

Developing successful Web-based learning environments has shown to be a challenging and difficult endeavor [7][11] that requires knowledge from multiple domains like pedagogy, psychology, knowledge engineering, software engineering, and Web technologies. Their lack of individual preferred ways of instruction is a challenge we address in this paper. We introduce a Web-based learning environment that teaches concepts from Artificial Intelligence to college students. This environment is intended to be used as a complementary tool for the standard lectures. By adapting the instruction and learning material to the individual student’s learning style the tutorial gives the student a personal learning experience and …

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Databases For Interval Probabilities, Wenzhong Zhao, Alex Dekhtyar, Judy Goldsmith Sep 2004

Databases For Interval Probabilities, Wenzhong Zhao, Alex Dekhtyar, Judy Goldsmith

Computer Science and Software Engineering

We present a database framework for the efficient storage and manipulation of interval probability distributions and their associated information. Although work on interval probabilities and on probabilistic databases has appeared before, ours is the first to combine these into a coherent and mathematically sound framework including both standard relational queries and queries based on probability theory. In particular, our query algebra allows users not only to query existing interval probability distributions, but also to construct new ones by means of conditionalization and marginalization, as well as other more common database operations.

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Helping Analysts Trace Requirements: An Objective Look, Jane Huffman Hayes, Alex Dekhtyar, Senthil Karthikeyan Sundaram, Sarah Howard Sep 2004

Helping Analysts Trace Requirements: An Objective Look, Jane Huffman Hayes, Alex Dekhtyar, Senthil Karthikeyan Sundaram, Sarah Howard

Computer Science and Software Engineering

This paper addresses the issues related to improving the overall quality of the requirements tracing process for Independent Verification and Validation analysts. The contribution of the paper is three-fold: we define requirements for a tracing tool based on analyst responsibilities in the tracing process; we introduce several new measures for validating that the requirements have been satisfied; and we present a prototype tool that we built, RETRO (REquirements TRacing On-target), to address these requirements. We also present the results of a study used to assess RETRO’s support of requirements and requirement elements that can be measured objectively.

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Possible Worlds Semantics For Probabilistic Logic Programs, Alex Dekhtyar, Michael I. Dekhtyar Sep 2004

Possible Worlds Semantics For Probabilistic Logic Programs, Alex Dekhtyar, Michael I. Dekhtyar

Computer Science and Software Engineering

In this paper we consider a logic programming framework for rea-soning about imprecise probabilities. In particular, we propose a new semantics, for the Probabilistic Logic Programs (p-programs) of Ng and Subrahmanian. P-programs represent imprecision using probability intervals. Our semantics, based on the possible worlds semantics, considers all point probability distributions that satisfy a given p-program. In the paper, we provide the exact characterization of such models of a p-program. We show that the set of models of a p-program can-not, in general case, be described by single intervals associated with atoms of the program. We provide algorithms for efficient construction …

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Basal Melting Along The Floating Part Of Byrd Glacier, James P. Kenneally, Terence J. Hughes Sep 2004

Basal Melting Along The Floating Part Of Byrd Glacier, James P. Kenneally, Terence J. Hughes

Earth Science Faculty Scholarship

A mass balance calculation was made for the floating part of Byrd Glacier, using 1978-79 ice elevation and velocity data, over the 45 km of Byrd Glacier from its grounding line to where it leaves its fjord and merges with the Ross Ice Shelf. Smoothed basal melting rates were relatively uniform over this distance and averaged 12 +/- 2 m yr(-1).

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Fracture And Back Stress Along The Byrd Glacier Flowband On The Ross Ice Shelf, James P. Kenneally, Terence J. Hughes Sep 2004

Fracture And Back Stress Along The Byrd Glacier Flowband On The Ross Ice Shelf, James P. Kenneally, Terence J. Hughes

Earth Science Faculty Scholarship

East Antarctic ice discharged by Byrd Glacier continues as a flowband to the calving front of the Ross Ice Shelf. Flow across the grounding line changes from compressive to extensive as it leaves the fjord through the Transantarctic Mountains occupied by Byrd Glacier. Magnitudes of the longitudinal compressive stress that suppress opening of transverse tensile cracks are calculated for the flowband. As compressive back stresses diminish, initial depths and subsequent growth of these cracks, and their spacing, are calculated using theories of elastic and ductile fracture mechanics. Cracks are initially about one millimeter wide, with approximately 30 in depths and …

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Polar Mm5 Simulations Of The Winter Climate Of The Laurentide Ice Sheet At The Lgm, David H. Bromwich, E. Richard Toracinta, Helin Wei, Robert J. Oglesby, James L. Fastook, Terence J. Hughes Sep 2004

Polar Mm5 Simulations Of The Winter Climate Of The Laurentide Ice Sheet At The Lgm, David H. Bromwich, E. Richard Toracinta, Helin Wei, Robert J. Oglesby, James L. Fastook, Terence J. Hughes

Earth Science Faculty Scholarship

Optimized regional climate simulations are conducted using the Polar MM5, a version of the fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5), with a 60-km horizontal resolution domain over North America during the Last Glacial Maximum (LGM, 21 000 calendar years ago), when much of the continent was covered by the Laurentide Ice Sheet (LIS). The objective is to describe the LGM annual cycle at high spatial resolution with an emphasis on the winter atmospheric circulation. Output from a tailored NCAR Community Climate Model version 3 (CCM3) simulation of the LGM climate is used to provide the initial and lateral boundary …

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Variations In Ice Rafted Detritus On Beaches In The South Shetland Islands: A Possible Climate Proxy, Brenda L. Hall, Ethan R. Perry Sep 2004

Variations In Ice Rafted Detritus On Beaches In The South Shetland Islands: A Possible Climate Proxy, Brenda L. Hall, Ethan R. Perry

Earth Science Faculty Scholarship

Raised beach ridges on Livingston Island of the South Shetland Islands display variations in both quantity and source of ice rafted detritus (IRD) received over time. Whereas the modem beach exhibits little IRD, all of which is of local origin, the next highest beach (similar to250 C-14 yr BP) has large amounts, some of which comes from as far away as the Antarctic Peninsula. Significant quantities of IRD also were deposited similar to 1750 C-14 yr BP. Both time periods coincide with generally cooler regional conditions and, at least in the case of the similar to250 yr old beach, local …

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Logic Programs, Iterated Function Systems, And Recurrent Radial Basis Function Networks, Sebastian Bader, Pascal Hitzler Sep 2004

Logic Programs, Iterated Function Systems, And Recurrent Radial Basis Function Networks, Sebastian Bader, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Graphs of the single-step operator for first-order logic programs—displayed in the real plane—exhibit self-similar structures known from topological dynamics, i.e., they appear to be fractals, or more precisely, attractors of iterated function systems. We show that this observation can be made mathematically precise. In particular, we give conditions which ensure that those graphs coincide with attractors of suitably chosen iterated function systems, and conditions which allow the approximation of such graphs by iterated function systems or by fractal interpolation. Since iterated function systems can easily be encoded using recurrent radial basis function networks, we eventually obtain connectionist systems which …

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Seasonal Aeration Rates For The Eastern United States Based On Long-Term Weather Patterns, Michael D. Montross, Samuel G. Mcneill, Thomas C. Bridges Sep 2004

Seasonal Aeration Rates For The Eastern United States Based On Long-Term Weather Patterns, Michael D. Montross, Samuel G. Mcneill, Thomas C. Bridges

Biosystems and Agricultural Engineering Faculty Publications

Most aeration fans are sized to produce a minimum airflow rate of 0.1 m3/min/t (0.1 cfm/bu) in on-farm grain storage structures. At this airflow rate a significant amount of time is required to move a cooling front completely through a bin. The desired grain temperature and prevailing weather conditions will have a significant effect on required fan size. Thirty years of weather data were analyzed for the eastern United States to determine the amount of time available in temperature windows between 0 to 15.C and 0 to 17.C. Contour maps were generated with ArcMap 8.3 for the percentage …

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Modeling And Propagation Of Near-Field Diffraction Patterns: A More Complete Approach, Glen D. Gillen, Shekhar Guha Sep 2004

Modeling And Propagation Of Near-Field Diffraction Patterns: A More Complete Approach, Glen D. Gillen, Shekhar Guha

Physics

We discuss the origins and regions of validity of various near-field diffraction models. The complete Rayleigh–Sommerfeld model is found to accurately represent intensity distributions for axial distances up to and including the location of the aperture, a region where commonly used models fail. We show that near-field diffraction theory can be applied to the refraction of light at an interface between two different media yielding results that demonstrate the validity of Snell’s law in the presence of diffraction. Calculations using near-field diffraction and Fourier optics are compared to experimentally measured intensity distributions

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Policies, Rules And Their Engines: What Do They Mean For Slas?, Mark Perry, Michael Bauer Sep 2004

Policies, Rules And Their Engines: What Do They Mean For Slas?, Mark Perry, Michael Bauer

Computer Science Publications

In our model for autonomic management of service level agreements (SLA), the roles played by policy and rules must be clearly differentiated. Although policy is typically an ideal we wish to achieve through the implementation of rules, the use of the terms policy and rule are often treated similarly and that consequently policy-engine and rule-engine are often used synonymously. It is our position that in the management of SLAs these terms have specific meanings. The definitions and models embodied are illustrated.

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Stratigraphic And Structural Features Of The Yeşi̇lbarak Nappe In Western Taurus Range And Its Comparison With The Similar Units In Se Anatolia And North Cyprus, Mustafa Şenel Sep 2004

Stratigraphic And Structural Features Of The Yeşi̇lbarak Nappe In Western Taurus Range And Its Comparison With The Similar Units In Se Anatolia And North Cyprus, Mustafa Şenel

Bulletin of the Mineral Research and Exploration

No abstract provided.

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The Nadca Probe, Issue 235 Sep 2004

The Nadca Probe, Issue 235

The Probe: Newsletter of the National Animal Damage Control Association


Some Extension perspectives on Wildlife Damage Management
Last Free Issue!
Calendar of Upcoming Events
What is the cost of treating a rattlesnake bite?
Introduction to Precharged Pneumatics
"Animal Crackers" by Dexter K. Oliver
Deer-Information Crash Information and Research Center
Wildlife Damage in the News- Faulty Felines
Wild Jaguars photographed in southern Arizona: Endangered Species Lives South of Tucscon
Face-to-Face With Wildlife/Human Conflicts

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High-Energy Ion Generation By Short Laser Pulses, Anatoly Maksimchuk, K. Flippo, H. Krause, G. Mourou, K. Nemoto, D. Schultz, Donald P. Umstadter, R. Vane, V. Yu. Bychenkov, G.I. Dudnikova, V.F. Kovalev, K. Mima, V.N. Novikov, Y. Sentoku, S.V. Tolokonnikov Sep 2004

High-Energy Ion Generation By Short Laser Pulses, Anatoly Maksimchuk, K. Flippo, H. Krause, G. Mourou, K. Nemoto, D. Schultz, Donald P. Umstadter, R. Vane, V. Yu. Bychenkov, G.I. Dudnikova, V.F. Kovalev, K. Mima, V.N. Novikov, Y. Sentoku, S.V. Tolokonnikov

Donald Umstadter Publications

This paper reviews the many recent advances at the Center for Ultrafast Optical Science (CUOS) at the University of Michigan in multi-MeV ion beam generation from the interaction of short laser pulses focused onto thin foil targets at intensities ranging from 1017 to 1019 W/cm2. Ion beam characteristics were studied by changing the laser intensity, laser wavelength, target material, and by depositing a well-absorbed coating. We manipulated the proton beam divergence using shaped targets and observed nuclear transformation induced by high-energy protons and deuterons. Qualitative theoretical approaches and fully relativistic two-dimensional particle-in-cell simulations modeled energetic ion …

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