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Completions Of P-Matrix Patterns, Luz M. DeAlba, Leslie Hogben 2017 Drake University

Completions Of P-Matrix Patterns, Luz M. Dealba, Leslie Hogben

Leslie Hogben

A list of positions in an n×n real matrix (a pattern) is said to have P-completion if every partial P-matrix that specifies exactly these positions can be completed to a P-matrix. We extend the work of C.R. Johnson, B.K. Kroschel [Electron. J. Linear Algebra Appl. 241–243 (1996) 655–657] by proving that a larger class of patterns has P-completion, including any 4×4 pattern with eight or fewer off-diagonal positions. We also show that any pattern whose digraph contains a minimally chordal symmetric-Hamiltonian induced subdigraph does not have P-completion.


Computation Of Minimal Rank And Path Cover Number For Certain Graphs, Francesco Barioli, Shaun Fallat, Leslie Hogben 2017 University of Regina

Computation Of Minimal Rank And Path Cover Number For Certain Graphs, Francesco Barioli, Shaun Fallat, Leslie Hogben

Leslie Hogben

For a given undirected graph G, the minimum rank of G is defined to be the smallest possible rank over all real symmetric matrices A whose (i, j)th entry is non-zero whenever i ≠ j and {i, j} is an edge in G. The path cover number of G is the minimum number of vertex-disjoint paths occurring as induced subgraphs of G that cover all the vertices of G. For trees, the relationship between minimum rank and path cover number is completely understood. However, for non-trees only sporadic results are known. We derive formulae for the minimum rank and path ...


Logic Circuits From Zero Forcing, Daniel Burgarth, Vittorio Giovannetti, Leslie Hogben, Simone Severini, Michael Young 2017 Aberystwyth University

Logic Circuits From Zero Forcing, Daniel Burgarth, Vittorio Giovannetti, Leslie Hogben, Simone Severini, Michael Young

Leslie Hogben

We design logic circuits based on the notion of zero forcing on graphs; each gate of the circuits is a gadget in which zero forcing is performed. We show that such circuits can evaluate every monotone Boolean function. By using two vertices to encode each logical bit, we obtain universal computation. We also highlight a phenomenon of “back forcing” as a property of each function. Such a phenomenon occurs in a circuit when the input of gates which have been already used at a given time step is further modified by a computation actually performed at a later stage. Finally ...


Constructions Of Potentially Eventually Positive Sign Patterns With Reducible Positive Part, Marie Archer, Minerva Catral, Craig Erickson, Rana Haber, Leslie Hogben, Xavier Martinez-Rivera, Antonio Ochoa 2017 Iowa State University

Constructions Of Potentially Eventually Positive Sign Patterns With Reducible Positive Part, Marie Archer, Minerva Catral, Craig Erickson, Rana Haber, Leslie Hogben, Xavier Martinez-Rivera, Antonio Ochoa

Leslie Hogben

Potentially eventually positive (PEP) sign patterns were introduced by Berman et al. (Electron. J. Linear Algebra 19 (2010), 108–120), where it was noted that a matrix is PEP if its positive part is primitive, and an example was given of a 3×3 PEP sign pattern with reducible positive part. We extend these results by constructing n×n PEP sign patterns with reducible positive part, for every n≥3.


Creating A Culture Of Evidence-Based Teaching Through Faculty Professional Development, Kirsten Fleming, David Polcyn 2017 California State University - San Bernardino

Creating A Culture Of Evidence-Based Teaching Through Faculty Professional Development, Kirsten Fleming, David Polcyn

Academic Chairpersons Conference Proceedings

This session will focus on leading change designed to instill a culture of equity-minded, evidence-based teaching and learning. Drawing on a community of practice model, a variety of professional development opportunities will be explored that enable STEM faculty members to redesign courses in ways that intentionally incorporates evidence-based teaching practices.


Developing And Supporting The Diversity Of Chairperson Roles, Jean Pawl, Richard Griner, Deborah Richardson, Elizabeth Nesmith 2017 Augusta University

Developing And Supporting The Diversity Of Chairperson Roles, Jean Pawl, Richard Griner, Deborah Richardson, Elizabeth Nesmith

Academic Chairpersons Conference Proceedings

A monthly Chair Professional Development program at Augusta University provides opportunity to mentor new chairpersons and foster collegiality amongst all chairpersons at a university with both liberal arts and health sciences programs. The merits and challenges of this program that addresses needs of such a diverse group will be highlighted


Leading Departments With Contingent And Tenure-Eligible Faculty: Strategies And Solutions, Diana L. Ashe, Matthew L. TenHuisen, Colleen A. Reilly 2017 University of North Carolina Wilmington

Leading Departments With Contingent And Tenure-Eligible Faculty: Strategies And Solutions, Diana L. Ashe, Matthew L. Tenhuisen, Colleen A. Reilly

Academic Chairpersons Conference Proceedings

Leadership and communication strategies for leading departments that include both contingent and tenure-eligible faculty through three case studies, dealing with 1) voting rights and other claims upon resources; 2) a lack of career milestones, making contingent faculty feel “stuck”; and 3) ways to value contributions of contingent faculty.


Atlanta University Center Faculty Publications: A Selective Bibliography, Robert W. Woodruff Library 2017 Atlanta University Center

Atlanta University Center Faculty Publications: A Selective Bibliography, Robert W. Woodruff Library

Atlanta University Center Faculty Scholarship Bibliographies

On February 28, 2006, the Robert W. Woodruff Library and the Library Advisory Council hosted an exhibit and reception to celebrate the scholarly publications of Atlanta University Center faculty. As a complement to that event, the Robert W. Woodruff Library developed the publication, Atlanta University Center Faculty Publications: A Brief Bibliography, which highlights selected scholarly and research contributions of the Atlanta University Center faculty.

The bibliography illustrates the richness of faculty contributions within each institution and across the Atlanta University Center community. The celebration has become an annual event and this compilation represents the next phase of a living document ...


Mathematical Beauty, Mike Janssen 2017 Dordt College

Mathematical Beauty, Mike Janssen

Faculty Work: Comprehensive List

"With all the brokenness in the world, is the study of the mathematical aspects of Creation worthwhile?"

Posting about ­­­­­­­­the beauty of mathematics from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world.

http://inallthings.org/mathematical-beauty/


The Opacity Of Spiral Galaxy Disks. Iii. Automating The Synthetic Field Method., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. van der Kruit 2017 University of Louisville

The Opacity Of Spiral Galaxy Disks. Iii. Automating The Synthetic Field Method., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. Van Der Kruit

Benne Holwerda

Dust extinction in spiral disks can be estimated from the counts of background field galaxies, provided the deleterious effects of confusion introduced by structure in the image of the foreground spiral disk can be calibrated. Gonzalez et al. developed a method for this calibration, the Synthetic Field Method (SFM), and applied this concept to a Hubble Space Telescope (HST )/Wide Field Planetary Camera 2 image of NGC 4536. The SFM estimates the total extinction through the disk without requiring assumptions about the distribution of absorbers or disk light. The poor statistics, however, result in large errors in individual measurements. We ...


The Opacity Of Spiral Galaxy Disks. Vi. Extinction, Stellar Light And Color., Benne W. Holwerda, R. A. Gonzalez, P. C. van der Kruit, R. J. Allen 2017 University of Louisville

The Opacity Of Spiral Galaxy Disks. Vi. Extinction, Stellar Light And Color., Benne W. Holwerda, R. A. Gonzalez, P. C. Van Der Kruit, R. J. Allen

Benne Holwerda

In this paper we explore the relation between dust extinction and stellar light distribution in disks of spiral galaxies. Extinction influences our dynamical and photometric perception of disks, since it can distort our measurement of the contribution of the stellar component. To characterize the total extinction by a foreground disk, González et al. (1998, ApJ, 506, 152) proposed the "Synthetic Field Method" (SFM), which uses the calibrated number of distant galaxies seen through the foreground disk as a direct indication of extinction. The method is described in González et al. (1998, ApJ, 506, 152) and Holwerda et al. (2005a, AJ ...


The Opacity Of Spiral Galaxy Disks Vii. The Accuracy Of Galaxy Counts As An Extinction Probe., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. van der Kruit 2017 University of Louisville

The Opacity Of Spiral Galaxy Disks Vii. The Accuracy Of Galaxy Counts As An Extinction Probe., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. Van Der Kruit

Benne Holwerda

The "Synthetic Field Method" (SFM) was introduced by González et al. (1998, ApJ, 506, 152) to calibrate numbers of distant galaxies as a probe of extinction in a foreground spiral disk. González et al. (2003, AJ, 125, 1182) studied the effect of the foreground disk on these numbers using simulations of current and future instruments for fields in the LMC, M 31 and NGC 4536, a galaxy in Virgo. They concluded that: (1) the brighter centers of disks were unsuitable; (2) the granularity of the disk at a fixed surface brightness is the limiting factor in the detection of distant ...


The Opacity Of Spiral Galaxy Disks. Iv. Radial Extinction Profiles From Counts Of Distant Galaxies Seen Through Foreground Disks., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. van der Kruit 2017 University of Louisville

The Opacity Of Spiral Galaxy Disks. Iv. Radial Extinction Profiles From Counts Of Distant Galaxies Seen Through Foreground Disks., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. Van Der Kruit

Benne Holwerda

Dust extinction can be determined from the number of distant field galaxies seen through a spiral disk. To calibrate this number for the crowding and confusion introduced by the foreground image, Gonzalez et al. and Holwerda et al. developed the Synthetic Field Method (SFM ), which analyzes synthetic fields constructed by adding various deep exposures of unobstructed background fields to the candidate foreground galaxy field. The advantage of the SFM is that it gives the average opacity for the area of a galaxy disk without making assumptions about either the distribution of absorbers or of the disk starlight. However, it is ...


The Opacity Of Spiral Galaxy Disks. V. Dust Opacity, Hi Distributions And Sub-Mm Emission., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. van der Kruit 2017 University of Louisville

The Opacity Of Spiral Galaxy Disks. V. Dust Opacity, Hi Distributions And Sub-Mm Emission., Benne W. Holwerda, R. A. Gonzalez, Ronald J. Allen, P. C. Van Der Kruit

Benne Holwerda

The opacity of spiral galaxy disks, from counts of distant galaxies, is compared to HI column densities. The opacity measurements are calibrated using the “Synthetic Field Method” from González et al. (1998, ApJ, 506, 152), Holwerda et al. (2005a, AJ, 129, 1381). When compared for individual disks, the HI column density and dust opacity do not seem to be correlated as HI and opacity follow different radial profiles. To improve statistics, an average radial opacity profile is compared to an average HI profile. Compared to dust-to-HI estimates from the literature, more extinction is found in this profile. This difference may ...


The Impact Of Low Self-Control On Online Harassment: Interaction With Opportunity., Hyunin Baek, Michael M. Losavio, George E. Higgins 2017 University of Louisville, Kentucky, USA.

The Impact Of Low Self-Control On Online Harassment: Interaction With Opportunity., Hyunin Baek, Michael M. Losavio, George E. Higgins

Journal of Digital Forensics, Security and Law

Developing Internet technology has increased the rates of youth online harassment. This study examines online harassment from adolescents with low self-control and the moderating effect of opportunity. The data used in this study were collected by the Korea Institute of Criminology in 2009. The total sample size was 1,091. The results indicated that low self-control, opportunity, and gender have a significant influence on online harassment. However, these results differed according to gender; for males, low self-control significantly impacted online harassment; for females, however, only low self-control significantly impacted online harassment. Furthermore, the interaction between low self-control and opportunity did ...


Best Sandbox, Tom Clark 2017 Dordt College

Best Sandbox, Tom Clark

Faculty Work: Comprehensive List

"Mathematics ought to be for everyone, not just for mathematicians, scientists, and engineers. Mathematics is not only about application; it is part of the created world."

Posting about ­­­­­­­­learning about math through creative play from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world.

http://inallthings.org/the-best-sandbox/


Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski 2017 Iowa State University

Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’Ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski

Duane D. Johnson

We use high resolution angle resolved photoemission spectroscopy and density functional theory with measured crystal structure parameters to study the electronic properties of CaKFe4As4. In contrast to the related CaFe2As2 compounds, CaKFe4As4 has a high Tc of 35 K at stochiometric composition. This presents a unique opportunity to study the properties of high temperature superconductivity in the iron arsenides in the absence of doping or substitution. The Fermi surface consists of several hole and electron pockets that have a range of diameters. We find that the values of the superconducting gap are nearly isotropic (within the explored portions of the ...


Chapter 14 – Evolutionary Algorithms Applied To Electronic-Structure Informatics: Accelerated Materials Design Using Data Discovery Vs. Data Searching, Duane D. Johnson 2017 Iowa State University

Chapter 14 – Evolutionary Algorithms Applied To Electronic-Structure Informatics: Accelerated Materials Design Using Data Discovery Vs. Data Searching, Duane D. Johnson

Duane D. Johnson

We exemplify and propose extending the use of genetic programs (GPs) – a genetic algorithm (GA) that evolves computer programs via mechanisms similar to genetics and natural selection – to symbolically regress key functional relationships between materials data, especially from electronic structure. GPs can extract structure–property relations or enable simulations across multiple scales of time and/or length. Uniquely, GP-based regression permits “data discovery” – finding relevant data and/or extracting correlations (data reduction/data mining) – in contrast to searching for what you know, or you think you know (intuition). First, catalysis-related materials correlations are discussed, where simple electronic-structure-based rules are revealed ...


Discovery Of Dirac Node Arcs In Ptsn4, Adam Kaminski, Paul C. Canfield, Serguei Bud'ko, Daixiang Mou, Eundeok Mun, Yun Wu, Lunan Huang, Yongbin Lee, Duane D. Johnson, Linlin Wang 2017 The Ames Laboratory, Iowa State University

Discovery Of Dirac Node Arcs In Ptsn4, Adam Kaminski, Paul C. Canfield, Serguei Bud'ko, Daixiang Mou, Eundeok Mun, Yun Wu, Lunan Huang, Yongbin Lee, Duane D. Johnson, Linlin Wang

Duane D. Johnson

In topological quantum materials the conduction and valence bands are connected at points (Dirac/Weyl semimetals) or along lines (Line Node semimetals) in the momentum space. Numbers of studies demonstrated that several materials are indeed Dirac/Weyl semimetals. However, there is still no experimental confirmation of materials with line nodes, in which the Dirac nodes form closed loops in the momentum space. Here we report the discovery of a novel topological structure - Dirac node arcs - in the ultrahigh magnetoresistive material PtSn4 using laser-based angle-resolved photoemission spectroscopy (ARPES) data and density functional theory (DFT) calculations. Unlike the closed loops of line ...


Asymmetric Mass Acquisition In Labi: Topological Semimetal Candidate, Yun Wu, Tai Kong, Lin-Lin Wang, Duane D. Johnson, Daixiang Mou, Lunan Huang, Benjamin Schrunk, Sergey L. Bud'ko, Paul C. Canfield, Adam Kaminski 2017 Iowa State University

Asymmetric Mass Acquisition In Labi: Topological Semimetal Candidate, Yun Wu, Tai Kong, Lin-Lin Wang, Duane D. Johnson, Daixiang Mou, Lunan Huang, Benjamin Schrunk, Sergey L. Bud'ko, Paul C. Canfield, Adam Kaminski

Duane D. Johnson

We use our high resolution He-lamp-based, tunable laser-based angle-resolved photoemission spectroscopy measurements and density functional theory calculations to study the electronic properties of LaBi, a binary system that was proposed to be a member of a new family of topological semimetals. Both bulk and surface bands are present in the spectra. The dispersion of the surface state is highly unusual. It resembles a Dirac cone, but upon closer inspection we can clearly detect an energy gap. The bottom band follows roughly a parabolic dispersion. The dispersion of the top band remains very linear, “V” -shape like, with the tip approaching ...


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