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2011

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Articles 7261 - 7290 of 7770

Full-Text Articles in Physical Sciences and Mathematics

Resonant Photoemission Of Rare Earth Doped Gan Thin Films, S. R. Mchale, J. W. Mcclory, J. C. Petrosky, J. Wu, R. Palai, Yaroslav B. Losovyj, Peter A. Dowben Jan 2011

Resonant Photoemission Of Rare Earth Doped Gan Thin Films, S. R. Mchale, J. W. Mcclory, J. C. Petrosky, J. Wu, R. Palai, Yaroslav B. Losovyj, Peter A. Dowben

Peter Dowben Publications

The 4d → 4f Fano resonances for various rare earth doped GaN thin films (RE = Gd, Er, Yb) were investigated using synchrotron photoemission spectroscopy. The resonant photoemission Fano profiles show that the major Gd and Er rare earth 4f weight is at about 5–6 eV below the valence band maximum, similar to the 4f weights in the valence band of many other rare earth doped semiconductors. For Yb, there is very little resonant enhancement of the valence band of Yb doped GaN, consistent with a largely 4f14 occupancy.


Direct Measurement Of The Mass Difference Between Top And Antitop Quarks, V. M. Abazov, Kenneth A. Bloom, Daniel Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory Snow, D0 Collaboration Jan 2011

Direct Measurement Of The Mass Difference Between Top And Antitop Quarks, V. M. Abazov, Kenneth A. Bloom, Daniel Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory Snow, D0 Collaboration

Kenneth Bloom Publications

We present a direct measurement of the mass difference between top and antitop quarks (∆m) in lepton + jets tt final states using the ‘‘matrix element’’ method. The purity of the lepton + jets sample is enhanced for tt events by identifying at least one of the jets as originating from a b quark. The analyzed data correspond to 3.6 fb-1 of pp collisions at √s = 1.96 TeV acquired by D0 in Run II of the Fermilab Tevatron Collider. The combination of the e + jets and µ + jets channels yields ∆m =0.8 ± 1,8 stat ± 0.5(syst) …


Measurement Of The B0s Production Cross Section With B0s → J/ Decays In Pp Collisions At √S = 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel Claes, Aaron Dominguez, Michael Eads, J Keller, T Kelly, Ilya Kravchenko, J. Lazo-Flores, Helena Malbouisson, Sudhir Malik, Gregory Snow, Cms Collaboration Jan 2011

Measurement Of The B0s Production Cross Section With B0s → J/ Decays In Pp Collisions At √S = 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel Claes, Aaron Dominguez, Michael Eads, J Keller, T Kelly, Ilya Kravchenko, J. Lazo-Flores, Helena Malbouisson, Sudhir Malik, Gregory Snow, Cms Collaboration

Kenneth Bloom Publications

The B0s differential production cross section is measured as functions of the transverse momentum and rapidity in pp collisions at √s= 7 TeV, using the B0s → J/UO decay, and compared with predictions based on perturbative QCD calculations at next-to-leading order. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 40 pb-1. The B0s is reconstructed from the decays J/U → µ+µ- and O→ K+K- The integrated B0s cross section times B0s→ J/UO branching fraction in the range 8BT …


Measurement Of The Anomalous Like-Sign Dimuon Charge Asymmetry With 9 Fb-1 Of Pp Collisions, V. M. Abazov, Kenneth A. Bloom, Daniel Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, S. Malik, Gregory Snow, D0 Collaboration Jan 2011

Measurement Of The Anomalous Like-Sign Dimuon Charge Asymmetry With 9 Fb-1 Of Pp Collisions, V. M. Abazov, Kenneth A. Bloom, Daniel Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, S. Malik, Gregory Snow, D0 Collaboration

Kenneth Bloom Publications

We present an updated measurement of the anomalous like-sign dimuon charge asymmetry AbSl for semileptonic b-hadron decays in 9.0 fb-1 of pp collisions recorded with the D0 detector at a center-of-mass energy of √s= 1.96 TeV at the Fermilab Tevatron collider. We obtain Absl = (-0.787 ± 0.172 (stat) ± 0.093 (syst)) %. This result differs by 3.9 standard deviations from the prediction of the standard model and provides evidence for anomalously large CP violation in semileptonic neutral B decay. The dependence of the asymmetry on the muon impact parameter is consistent with the hypothesis that …


Forward-Backward Asymmetry In Top Quark-Antiquark Production, V. M. Abazov, Kenneth A. Bloom, Daniel R. Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory Snow, D0 Collaboration Jan 2011

Forward-Backward Asymmetry In Top Quark-Antiquark Production, V. M. Abazov, Kenneth A. Bloom, Daniel R. Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory Snow, D0 Collaboration

Kenneth Bloom Publications

We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a data set corresponding to an integrated luminosity of 5.4 fb-1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the tt̅ forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2± …


Search For A Fourth Generation Tl Quark In Pp̅ Collisions At √S= 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Daniel R. Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory R. Snow Jan 2011

Search For A Fourth Generation Tl Quark In Pp̅ Collisions At √S= 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Daniel R. Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory R. Snow

Kenneth Bloom Publications

We present a search for pair production of a fourth generation tl quark and its antiparticle, followed by their decays to a W boson and a jet, based on an integrated luminosity of 5.3 fb-1 of proton-antiproton collisions at √s= 1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the tlt-l production cross section that exclude at the 95% C.L. a tl quark that decays exclusively to W + jet with a mass below 285 GeV. We observe a small excess in the µ + …


Search For Three-Jet Resonances In Pp Collisions At √S= 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, P. Jindal, J. Keller, T Kelly, Ilya Kravchenko, J. Lazo-Flores, Sudhir Malik, Gregory Snow, Helena Malbouisson Jan 2011

Search For Three-Jet Resonances In Pp Collisions At √S= 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, P. Jindal, J. Keller, T Kelly, Ilya Kravchenko, J. Lazo-Flores, Sudhir Malik, Gregory Snow, Helena Malbouisson

Kenneth Bloom Publications

A search for three-jet hadronic resonance production in pp collisions at a center-of-mass energy of 7 TeV has been conducted by the CMS Collaboration at the LHC, using a data sample corresponding to an integrated luminosity of 35 pb-1. Events with high jet multiplicity and a large scalar sum of jet transverse momenta are analyzed using a signature-based approach. The number of expected standard model background events is found to be in good agreement with the observed events. Limits on the cross section times branching ratio are set in a model of gluino pair production with an R …


Precision Measurement Of The Ratio B(T→Wb)/B(T→Wq) And Extraction Of Vtb, V. M. Abazov, Kenneth A. Bloom, Daniel R. Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory Snow Jan 2011

Precision Measurement Of The Ratio B(T→Wb)/B(T→Wq) And Extraction Of Vtb, V. M. Abazov, Kenneth A. Bloom, Daniel R. Claes, Kayle Devaughan, Aaron Dominguez, Michael Eads, D. Johnston, Ioannis Katsanos, Sudhir Malik, Gregory Snow

Kenneth Bloom Publications

We present a measurement of the ratio of top quark branching fractions R= B(t→Wb)/B(t→Wq), where q can be a d, s, or b quark, in the lepton + jets and dilepton tt̅ final states. The measurement uses data from 5.4 fb-1 of pp̅ collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure R = 0.90±0.04, and we extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element │Vtb│ as │Vtb│= 0.95 ± 0.02, assuming unitarity of the 3X3 CKM matrix.


Measurement Of The Inclusive Jet Cross Section In Pp Collisions At √S= 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel Claes, Aaron Dominguez, Michael Eads, J Keller, T Kelly, Ilya Kravchenko, J. Lazo-Flores, Helena Malbouisson, Sudhir Malik, Gregory Snow Jan 2011

Measurement Of The Inclusive Jet Cross Section In Pp Collisions At √S= 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel Claes, Aaron Dominguez, Michael Eads, J Keller, T Kelly, Ilya Kravchenko, J. Lazo-Flores, Helena Malbouisson, Sudhir Malik, Gregory Snow

Kenneth Bloom Publications

The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeVat the Large Hadron Collider using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 pb-1. The measurement is made for jet transverse momenta in the range 18–1100 GeVand for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jetpT ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leadingorder perturbative QCD predictions.


Search For Avectorlike Quarkwith Charge 2/3 In T + Z Events From Pp Collisions At √S = 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, P. Jindal, J. Keller, T. Kelly, Ilya Kravchenko, J. Lazo-Flores, H. Malbouisson, Sudhir Malik, Gregory Snow Jan 2011

Search For Avectorlike Quarkwith Charge 2/3 In T + Z Events From Pp Collisions At √S = 7 Tev, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, P. Jindal, J. Keller, T. Kelly, Ilya Kravchenko, J. Lazo-Flores, H. Malbouisson, Sudhir Malik, Gregory Snow

Kenneth Bloom Publications

A search for pair-produced heavy vectorlike charge-2/3 quarks, T, in pp collisions at a center-of-mass energy of 7 TeV, is performed with the CMS detector at the LHC. Events consistent with the flavorchanging- neutral-current decay of a T quark to a top quark and a Z boson are selected by requiring two leptons from the Z-boson decay, as well as an additional isolated charged lepton. In a data sample corresponding to an integrated luminosity of 1.14 fb-1, the number of observed events is found to be consistent with the standard model background prediction. Assuming a branching …


Search For Supersymmetry At The Lhc In Events With Jets And Missing Transverse Energy, Cms Collaboration, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, P. Jindal, J. Keller, T. Kelly, Ilya Kravchenko, J. Lazo-Flores, H. Malbouisson, Sudhir Malik, Gregory Snow Jan 2011

Search For Supersymmetry At The Lhc In Events With Jets And Missing Transverse Energy, Cms Collaboration, S. Chatrchyan, Kenneth A. Bloom, S. Bose, Jamila Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, P. Jindal, J. Keller, T. Kelly, Ilya Kravchenko, J. Lazo-Flores, H. Malbouisson, Sudhir Malik, Gregory Snow

Kenneth Bloom Publications

A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at √s = 7 TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1.14 fb-1. In this search, a kinematic variable αT is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found. Exclusion limits in the parameter space of the constrained minimal supersymmetric extension of the standard model are set. In …


Estimates Of Duck Breeding Populations In The Nebraska Sandhills Using Double Observer Methodology, Mark P. Vrtiska, Larkin A. Powell Jan 2011

Estimates Of Duck Breeding Populations In The Nebraska Sandhills Using Double Observer Methodology, Mark P. Vrtiska, Larkin A. Powell

School of Natural Resources: Faculty Publications

The Nebraska Sandhills are an important area for breeding ducks in the Great Plains, but reliable estimates of breeding populations are unavailable. Double-observer methodology was used to estimate abundance of breeding duck populations in the Nebraska Sandhills. Aerial transect surveys were conducted using methodology similar to the cooperative Waterfowl Breeding Population and Habitat Survey conducted by the U.S. Fish and Wildlife Service and Canadian Wildlife Service. Observations by two front-seat observers and one rear-seat observer were used to account for incomplete detectability. Transect-specific population size and detection probabilities were estimated using program SURVIV; estimates were species-specific by type of social …


Active Use Of Coyotes (Canis Latrans) To Detect Bovine Tuberculosis In Northeastern Michigan, Usa, Are R. Berentsen, Michael R. Dunbar, Shylo R. Johnson, S. Robbe-Austerman, L. Martinez, R. L. Jones Jan 2011

Active Use Of Coyotes (Canis Latrans) To Detect Bovine Tuberculosis In Northeastern Michigan, Usa, Are R. Berentsen, Michael R. Dunbar, Shylo R. Johnson, S. Robbe-Austerman, L. Martinez, R. L. Jones

United States Department of Agriculture Wildlife Services: Staff Publications

Bovine tuberculosis (bTB) is endemic in white-tailed deer (Odocoileus virginianus) in northeastern Michigan, USA, and research suggests transmission to cattle. Prevalence of the disease in deer is estimated at 1.8%, but as prevalence decreases the difficulty of detection increases. Research suggests coyotes (Canis latrans) have a higher prevalence of bTB in Michigan than deer and sampling coyotes may be a more efficient surveillance tool to detect presence or spread of the disease. Coyotes possess suitable ecological characteristics to serve as a sentinel species, assuming transmission between coyotes is not significant. The question of whether free-ranging coyotes shed Mycobacterium bovis, the …


The Carrot Or The Stick? Evaluation Of Education And Enforcement As Management Tools For Human-Wildlife Conflicts., Sharon Baruch-Mordo, Stewart W. Breck, Kenneth R. Wilson, John Broderick Jan 2011

The Carrot Or The Stick? Evaluation Of Education And Enforcement As Management Tools For Human-Wildlife Conflicts., Sharon Baruch-Mordo, Stewart W. Breck, Kenneth R. Wilson, John Broderick

United States Department of Agriculture Wildlife Services: Staff Publications

Evidence-based decision-making is critical for implementing conservation actions, especially for human-wildlife conflicts, which have been increasing worldwide. Conservation practitioners recognize that long-term solutions should include altering human behaviors, and public education and enforcement of wildlife-related laws are two management actions frequently implemented, but with little empirical evidence evaluating their success. We used a system where human-black bear conflicts were common, to experimentally test the efficacy of education and enforcement in altering human behavior to better secure attractants (garbage) from bears. We conducted 3 experiments in Aspen CO, USA to evaluate: 1) on-site education in communal dwellings and construction sites, 2) …


Vulture Flight Behavior And Implications For Aircraft Safety, Michael L. Avery, John S. Humphrey, Trey S. Daughtery, Justin W. Fischer, Michael P. Milleson, Eric A. Tillman, William E. Bruce, W. David Walter Jan 2011

Vulture Flight Behavior And Implications For Aircraft Safety, Michael L. Avery, John S. Humphrey, Trey S. Daughtery, Justin W. Fischer, Michael P. Milleson, Eric A. Tillman, William E. Bruce, W. David Walter

United States Department of Agriculture Wildlife Services: Staff Publications

Growing vulture populations represent increasing hazards to civil and military aircraft. To assess vulture flight behavior and activity patterns at the Marine Corps Air Station in Beaufort, South Carolina, we equipped 11 black vultures (Coragyps atratus) and 11 turkey vultures (Cathartes aura) with solarpowered Global Positioning System (GPS) satellite transmitters during a 2-year study (1 Oct 2006–30 Sep 2008). Turkey vultures had larger seasonal home ranges than did black vultures, and 2 turkey vultures made round-trips to Florida. Black vultures consistently spent less time in flight (8.4%) than did turkey vultures (18.9%), and black vultures flew at higher altitudes than …


Efficacy Of European Starling Control To Reduce Salmonella Enterica Contamination In A Concentrated Animal Feeding Operation In The Texas Panhandle, James C. Carlson, Richard M. Engeman, Doreene R. Hyatt, Rickey L. Gilliland, Thomas J. Deliberto, Larry Clark, Michael J. Bodenchuck, George M. Linz Jan 2011

Efficacy Of European Starling Control To Reduce Salmonella Enterica Contamination In A Concentrated Animal Feeding Operation In The Texas Panhandle, James C. Carlson, Richard M. Engeman, Doreene R. Hyatt, Rickey L. Gilliland, Thomas J. Deliberto, Larry Clark, Michael J. Bodenchuck, George M. Linz

United States Department of Agriculture Wildlife Services: Staff Publications

Background: European starlings (Sturnus vulgaris) are an invasive bird species known to cause damage to plant and animal agriculture. New evidence suggests starlings may also contribute to the maintenance and spread of diseases within livestock facilities. Identifying and mitigating the risk pathways that contribute to disease in livestock is necessary to reduce production losses and contamination of human food products. To better understand the impact starlings have on disease transmission to cattle we assessed the efficacy of starling control as a tool to reduce Salmonella enterica within a concentrated animal feeding operation. We matched a large facility, slated for operational …


Nilgai Antelope In Northern Mexico As A Possible Carrier For Cattle Fever Ticks And Babesia Bovis And Babesia Bigemina., E M. Cardenas-Canales, J. Alfonso Ortega-Santos, Tyler A. Campbell, Zeferino Garcia-Vaquez, Antonio Cantu-Covarrubias, Julio V. Figueroa-Millian, Randy W. Deyoung, David G. Hewitt, Fred C. Bryant Jan 2011

Nilgai Antelope In Northern Mexico As A Possible Carrier For Cattle Fever Ticks And Babesia Bovis And Babesia Bigemina., E M. Cardenas-Canales, J. Alfonso Ortega-Santos, Tyler A. Campbell, Zeferino Garcia-Vaquez, Antonio Cantu-Covarrubias, Julio V. Figueroa-Millian, Randy W. Deyoung, David G. Hewitt, Fred C. Bryant

United States Department of Agriculture Wildlife Services: Staff Publications

Of 20 blood samples from nilgais from Me´ xico, five were polymerase chain reaction-positive for Babesia bigemina and one for Babesia bovis. Positive samples had the expected 170 (B. bigemina) and 291 (B. bovis) base pairs and were identical to Gen-Bank B. bigemina accession S45366 and B. bovis M38218.


Diseases And Parasites, Kurt C. Vercauteren, Tyler A. Campbell Jan 2011

Diseases And Parasites, Kurt C. Vercauteren, Tyler A. Campbell

United States Department of Agriculture Wildlife Services: Staff Publications

No abstract provided.


Efficacy Of The Boar-Operated-System To Deliver Baits To Feral Swine., Tyler A. Campbell, David B. Long, Giovanna Massei Jan 2011

Efficacy Of The Boar-Operated-System To Deliver Baits To Feral Swine., Tyler A. Campbell, David B. Long, Giovanna Massei

United States Department of Agriculture Wildlife Services: Staff Publications

Feral swine (Sus scrofa) pose a significant disease threat to livestock and humans. Emerging technologies to reduce feral swine disease transmission risks include fertility control, vaccination, and toxicants. However, for these technologies to be appropriate for field application, a feral swine-specific oral delivery system is needed. We used two field trials to generate information related to appropriate field application of the Boar-Operated-System (BOSTM), an oral delivery system designed to provide bait access only to feral swine. Our objectives were to determine whether pre-baiting BOSTM units increased bait removal and to evaluate the proportion of feral swine and non-target animals that …


Extremal Problems For Independent Set Enumeration, Jonathan Cutler, A. J. Radcliffe Jan 2011

Extremal Problems For Independent Set Enumeration, Jonathan Cutler, A. J. Radcliffe

Department of Mathematics: Faculty Publications

The study of the number of independent sets in a graph has a rich history. Recently, Kahn proved that disjoint unions of Kr,r’s have the maximum number of independent sets amongst r-regular bipartite graphs. Zhao extended this to all r-regular graphs. If we instead restrict the class of graphs to those on a fixed number of vertices and edges, then the Kruskal-Katona theorem implies that the graph with the maximum number of independent sets is the lex graph, where edges form an initial segment of the lexicographic ordering. In this paper, we study three related questions. Firstly, we …


An Entropy Proof Of The Kahn-Lovasz Theorem, Jonathan Cutler, A. J. Radcliffe Jan 2011

An Entropy Proof Of The Kahn-Lovasz Theorem, Jonathan Cutler, A. J. Radcliffe

Department of Mathematics: Faculty Publications

Bregman [2], gave a best possible upper bound for the number of perfect matchings in a balanced bipartite graph in terms of its degree sequence. Recently Kahn and Lovasz [8] extended Bregman’s theorem to general graphs. In this paper, we use entropy methods to give a new proof of the Kahn-Lovasz theorem. Our methods build on Radhakrishnan’s [9] use of entropy to prove Bregman’s theorem.


Evolution Of Large Carnivores During The Mid-Cenozoic Of North America: The Temnocyonine Radiation (Mammalia, Amphicyonidae) Robert M., Robert M. Hunt Jr. Jan 2011

Evolution Of Large Carnivores During The Mid-Cenozoic Of North America: The Temnocyonine Radiation (Mammalia, Amphicyonidae) Robert M., Robert M. Hunt Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

This study describes and summarizes the Temnocyoninae (Mammalia, Carnivora), a subfamily of amphicyonid carnivores of considerable diversity and singular ecomorphology within Cenozoic faunas of North America. In temnocyonines, we see the first carnivorans to occupy an ecological niche as large cursorial predators. The subfamily is confined to the Arikareean NALMA, ranging in age from the latest early Oligocene to the early Miocene. Distributed from the Pacific Northwest to the Great Plains and Florida, there are four genera (Temnocyon, Mammacyon, Delotrochanter n. gen., Rudiocyon n. gen.) and 12 species, of which eight are newly described (Temnocyon subferox …


Mass Wasting As A Geologic Hazard In The Province Of Salta, Argentina, William J. Wayne Jan 2011

Mass Wasting As A Geologic Hazard In The Province Of Salta, Argentina, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

The north-south orient ation ofthe mo unta inous part ofthe Province ofSalta form s a massive barrier to easy communication between the more populate d region in the central pan of the provin ce and the communities to the west. Routes follow deeply entrenched valleys th at are frequ entl y th e sites ofdebris flows that cause disruptions in th e flow of traffic during the months of December through March , wh en most of the precipitation of the region is recorded . The steep topography and the tecton ic settings have resulted in nearly 150 large landslides …


Short-Term Facilitation May Stabilize Parametric Working Memory Trace, Vladimir Itskov, David Hansel, Misha Tsodyks Jan 2011

Short-Term Facilitation May Stabilize Parametric Working Memory Trace, Vladimir Itskov, David Hansel, Misha Tsodyks

Department of Mathematics: Faculty Publications

Networks with continuous set of attractors are considered to be a paradigmatic model for parametric working memory (WM), but require fine tuning of connections and are thus structurally unstable. Here we analyzed the network with ring attractor, where connections are not perfectly tuned and the activity state therefore drifts in the absence of the stabilizing stimulus. We derive an analytical expression for the drift dynamics and conclude that the network cannot function as WM for a period of several seconds, a typical delay time in monkey memory experiments. We propose that short-term synaptic facilitation in recurrent connections significantly improves the …


Distribution And Properties Of Vesicular Horizons In The Western United States, Judith K. Turk, Robert C. Graham Jan 2011

Distribution And Properties Of Vesicular Horizons In The Western United States, Judith K. Turk, Robert C. Graham

Conservation and Survey Division: Faculty and Staff Publications

Vesicular horizons are thin (usuallycm) surface or near-surface horizons characterized by the predominance of vesicular porosity. Th ey are widespread in arid and semiarid lands, occurring on every continent and covering 156,000 km2 of the western United States. Vesicular horizons have critical implications for management due to their role in controlling surface hydrology and dust mobilization. Th is study evaluates the distribution and varia-tion in expression of vesicular horizons across the western United States using the soil databases available from the USDA. A vesicular horizon index (VHI) that incorporates vesicular horizon thickness and the size and quantity of vesicular pores …


A Reformulation Strategy For Multi-Dimensional Csps: The Case Study Of The Set Game, Amanda Swearngin, Berthe Y. Choueiry, Eugene C. Freuder Jan 2011

A Reformulation Strategy For Multi-Dimensional Csps: The Case Study Of The Set Game, Amanda Swearngin, Berthe Y. Choueiry, Eugene C. Freuder

School of Computing: Conference and Workshop Papers

In this paper we describe a reformulation strategy for solving multi-dimensional Constraint Satisfaction Problems (CSPs). This strategy operates by iteratively considering, in isolation, each one of the uni-dimensional constraints in the problem. It exploits the approximate symmetries identified on the domain values in order to enforce the selected constraint on the simplified problem. This paper uses the game of SET, a combinatorial card game, to motivate and illustrate our strategy. We propose a multi-dimensional constraint model for SET, and describe a basic constraint solver for finding all solutions of an instance of the game. Then, we introduce an algorithm that …


A Reformulation Strategy For Multi-Dimensional Csps: The Case Study Of The Set Game, Amanda Swearngin, Berthe Y. Choueiry, Robert J. Woodward, Eugene C. Freuder Jan 2011

A Reformulation Strategy For Multi-Dimensional Csps: The Case Study Of The Set Game, Amanda Swearngin, Berthe Y. Choueiry, Robert J. Woodward, Eugene C. Freuder

School of Computing: Conference and Workshop Papers

•General reformulation strategy for CSPs

–Multidimensional CSPs (MD-CSPs)

–Problem reformulation by value interchangeability

–A general reformulation strategy for MD-CSPs

•Game of Set: A new toy problem

–Game, CSP model

–Problem reformulation

–Algorithms & Results

•Conclusions


Reformulating The Dual Graphs Of Csps To Improve The Performance Of Relational Neighborhood Inverse Consistency, Robert J. Woodward, Shant Karakashian, Berthe Y. Choueiry, Christian Bessiere Jan 2011

Reformulating The Dual Graphs Of Csps To Improve The Performance Of Relational Neighborhood Inverse Consistency, Robert J. Woodward, Shant Karakashian, Berthe Y. Choueiry, Christian Bessiere

School of Computing: Conference and Workshop Papers

Freuder and Elfe (1996) introduced Neighborhood Inverse Consistency (NIC) as a new local consistency property for binary Constraint Satisfaction Problems (CSPs). Two advantages of the algorithm for enforcing NIC is that it automatically adapts its filtering power to the local connectivity of the network and has insignificant space overhead. However, studies on binary CSPs have shown that enforcing NIC is not effective on sparse graphs and too costly on dense graphs. In (Woodward et al. 2011), we introduced an algorithm for enforcing Relational Neighborhood Inverse Consistency (RNIC), which is an extension of NIC to non-binary CSPs. In this paper, we …


Reformulating The Dual Graphs Of Csps To Improve The Performance Of Rnic, Robert J. Woodward, Shant Karakashian, Berthe Y. Choueiry, Christian Bessiere Jan 2011

Reformulating The Dual Graphs Of Csps To Improve The Performance Of Rnic, Robert J. Woodward, Shant Karakashian, Berthe Y. Choueiry, Christian Bessiere

School of Computing: Conference and Workshop Papers

•Introduction

•Relational Neighborhood Inverse Consistency

–Property & algorithm

•Reformulating the Dual Graph by

1.Removing redundant edges, yields property wRNIC

2.Triangulation, yields property triRNIC

•Selection strategy: four alternative dual graphs

•Experimental Results

•Conclusion


Reformulating R(*;M)C With Tree Decomposition, Shant Karakashian, Robert J. Woodward, Berthe Y. Choueiry Jan 2011

Reformulating R(*;M)C With Tree Decomposition, Shant Karakashian, Robert J. Woodward, Berthe Y. Choueiry

School of Computing: Conference and Workshop Papers

Local consistency properties and algorithms for enforcing them are central to the success of Constraint Processing. Recently, we have demonstrated the importance of higher levels of consistency and the effectiveness of their algorithms for solving difficult problems (Karakashian et al. 2010; Woodward et al. 2011). In this paper, we introduce two reformulation techniques for improving the effectiveness of our algorithm for the relational consistency property R(*;m)C (Karakashian et al. 2010). Both techniques exploit a tree decomposition of the constraint network of a Constraint Satisfaction Problem (CSP), which is a tree embedding of the network. Our first reformulation technique …