Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2015

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1441 - 1470 of 12617

Full-Text Articles in Physical Sciences and Mathematics

Dreissenid Mussel Research Priorities Workshop, Mark D. Sytsma, Stephen Phillips, Timothy D. Counihan Nov 2015

Dreissenid Mussel Research Priorities Workshop, Mark D. Sytsma, Stephen Phillips, Timothy D. Counihan

Center for Lakes and Reservoirs Publications and Presentations

Currently, dreissenid mussels have yet to be detected in the northwestern part of the United States and western Canada. Infestation of one of the jurisdictions within the mussel-free Pacific Northwest would likely have significant economic, soci­etal and environmental implications for the entire region. Understanding the biology and environmental tolerances of dreissenid mussels, and effectiveness of various man­agement strategies, is key to prevention.

On November 4-5, 2015, the Aquatic Bioinvasion Research and Policy Institute and the Center for Lakes and Reservoirs at Portland State University, the US Geological Survey, and the Pacific States Marine Fisheries Commission, convened a Dreissenid Mussel Research …


Galaxy And Mass Assembly (Gama) : The Bright Void Galaxy Population In The Optical And Mid-Ir., S. J. Penny, M. J. I. Brown, K. A. Pimbblet, M. E. Cluver, D. J. Croton, M. S. Owers, R. Lange, M. Alpaslan, I. K. Baldry, J. Bland-Hawthorn, S. Brough, S. P. Driver, Benne W. Holwerda, A. M. Hopkins, T. H. Jarrett, D. Heath Jones, L. S. Kelvin, M. A. Lara-Lopez, J. Liske, Angel R. Lopez-Sanchez, J. Loveday, M. Meyer, P. Norberg, A. S. G. Robotham, M. Rodrigues Nov 2015

Galaxy And Mass Assembly (Gama) : The Bright Void Galaxy Population In The Optical And Mid-Ir., S. J. Penny, M. J. I. Brown, K. A. Pimbblet, M. E. Cluver, D. J. Croton, M. S. Owers, R. Lange, M. Alpaslan, I. K. Baldry, J. Bland-Hawthorn, S. Brough, S. P. Driver, Benne W. Holwerda, A. M. Hopkins, T. H. Jarrett, D. Heath Jones, L. S. Kelvin, M. A. Lara-Lopez, J. Liske, Angel R. Lopez-Sanchez, J. Loveday, M. Meyer, P. Norberg, A. S. G. Robotham, M. Rodrigues

Faculty and Staff Scholarship

We examine the properties of galaxies in the Galaxies and Mass Assembly (GAMA) survey located in voids with radii >10 h−1 Mpc. Utilizing the GAMA equatorial survey, 592 void galaxies are identified out to z ≈ 0.1 brighter than Mr = −18.4, our magnitude completeness limit. Using the WHα versus [N ii]/Hα (WHAN) line strength diagnostic diagram, we classify their spectra as star forming, AGN, or dominated by old stellar populations. For objects more massive than 5 × 109 M⊙, we identify a sample of 26 void galaxies with old stellar populations classed as passive and retired …


Why It Is Difficult To Apply Revenue Management Techniques To The Car Rental Business And What Can Be Done About It, Robert F. Gordon Ph.D. Nov 2015

Why It Is Difficult To Apply Revenue Management Techniques To The Car Rental Business And What Can Be Done About It, Robert F. Gordon Ph.D.

Faculty Works: MCS (1984-2023)

Revenue management systems are used by airlines, hotels, and cruise lines to manipulate prices and availability of inventory in real-time, in order to increase profit. We discuss the reasons that the revenue management problem is more complex when applied to the car rental business. We then show how to simplify the model formulation and provide the human-computer interaction, organization, and procedures to make the problem tractable for the car rental business.


Data Selection Using Topic Adaptation For Statistical Machine Translation, Hitokazu Matsushita Nov 2015

Data Selection Using Topic Adaptation For Statistical Machine Translation, Hitokazu Matsushita

Theses and Dissertations

Statistical machine translation (SMT) requires large quantities of bitexts (i.e., bilingual parallel corpora) as training data to yield good quality translations. While obtaining a large amount of training data is critical, the similarity between training and test data also has a significant impact on SMT performance. Many SMT studies define data similarity in terms of domain-overlap, and domains are defined to be synonymous with data sources. Consequently, the SMT community has focused on domain adaptation techniques that augment small (in-domain) datasets with large datasets from other sources (hence, out-of-domain, per the definition). However, many training datasets consist of topically diverse …


Building 3d-Printed Widgets To Incorporate Into Prototypes, David E. Brandt Nov 2015

Building 3d-Printed Widgets To Incorporate Into Prototypes, David E. Brandt

Theses and Dissertations

Creating interactive prototypes can be a long and difficult process. It requires expertise in various fields. Prior work in developing interactive prototypes minimize time required to make a prototype, but generally sacrifice fidelity for fluidity. Advances in 3D printing create new opportunities to prototype with greater fidelity and fluidity. We investigate the use of several kinds of sensors, including IR photo interrupters, IR photo reflectors, push button switches, and potentiometers, to create interactive prototypes. We first design a library of 3D printable interaction components, buttons, sliders, and knobs using those sensors then we develop software to transform interaction events into …


Stafford County Shoreline Management Plan, C. Scott Hardaway Jr., Donna A. Milligan, Christine A. Wilcox, Marcia Berman, Tamia Rudnicky, Karinna Nunez, Sharon Kileen Nov 2015

Stafford County Shoreline Management Plan, C. Scott Hardaway Jr., Donna A. Milligan, Christine A. Wilcox, Marcia Berman, Tamia Rudnicky, Karinna Nunez, Sharon Kileen

Reports

With approximately 85 percent of the Chesapeake Bay shoreline privately owned, a critical need exists to increase awareness of erosion potential and the choices available for shore stabilization that maintains ecosystem services at the land-water interface. The National Academy of Science published a report that spotlights the need to develop a shoreline management framework (NRC, 2007). It suggests that improving awareness of the choices available for erosion control, considering cumulative consequences of erosion mitigation approaches, and improving shoreline management planning are key elements to minimizing adverse environmental impacts associated with mitigating shore erosion. Actions taken by waterfront property owners to …


Crystal Structures Of Tris­[1-Oxo­Pyridine-2-Olato(1-)]Silicon(Iv) Chloride Chloro­Form-D1 Disolvate, Tris­[1-Oxo­Pyridine-2-Olato(1-)]Silicon(Iv) Chloride Aceto­Nitrile Unqu­Anti­Fied Solvate, And Fac-Tris­[1-Oxo­Pyridine-2-Thiol­Ato(1-)]Silicon(Iv) Chloride Chloro­Form-D1 Disolvate, Bradley M. Kraft, William W. Brennessel, Amy E. Ryan, Candace K. Benjamin Nov 2015

Crystal Structures Of Tris­[1-Oxo­Pyridine-2-Olato(1-)]Silicon(Iv) Chloride Chloro­Form-D1 Disolvate, Tris­[1-Oxo­Pyridine-2-Olato(1-)]Silicon(Iv) Chloride Aceto­Nitrile Unqu­Anti­Fied Solvate, And Fac-Tris­[1-Oxo­Pyridine-2-Thiol­Ato(1-)]Silicon(Iv) Chloride Chloro­Form-D1 Disolvate, Bradley M. Kraft, William W. Brennessel, Amy E. Ryan, Candace K. Benjamin

Chemistry Faculty/Staff Publications

The cations in the title salts, [Si(OPO)3]Cl·2CDCl3, (I), [Si(OPO)3]Cl·xCH3CN, (II), and fac-[Si(OPTO)3]Cl·2CDCl3, (III) (OPO = 1-oxo-2-pyridin­one, C5H4NO2, and OPTO = 1-oxo-2-pyridine­thione, C5H4NOS), have distorted octa­hedral coordination spheres. The first two structures contain the same cation and anion, but different solvents of crystallization led to different solvates and packing arrangements. In structures (I) and (III), the silicon complex cations and chloride anions are well separated, while in (II), there are two C-HCl distances that fall just within the sum of the van der Waals radii of the C and Cl atoms. The pyridine portions of the OPO ligands …


Interactive Machine Assistance: A Case Study In Linking Corpora And Dictionaries, Kevin P. Black Nov 2015

Interactive Machine Assistance: A Case Study In Linking Corpora And Dictionaries, Kevin P. Black

Theses and Dissertations

Machine learning can provide assistance to humans in making decisions, including linguistic decisions such as determining the part of speech of a word. Supervised machine learning methods derive patterns indicative of possible labels (decisions) from annotated example data. For many problems, including most language analysis problems, acquiring annotated data requires human annotators who are trained to understand the problem and to disambiguate among multiple possible labels. Hence, the availability of experts can limit the scope and quantity of annotated data. Machine-learned pre-annotation assistance, which suggests probable labels for unannotated items, can enable expert annotators to work more quickly and thus …


Galaxy And Mass Assembly (Gama) : The Wavelength Dependence Of Galaxy Structure Versus Redshift And Luminosity., Rebecca Kennedy, Steven P. Bamford, Ivan K. Baldry, Boris Haußler, Benne W. Holwerda, Andrew M. Hopkins, Lee S. Kelvin, Rebecca Lange, Amanda J. Moffett, Cristina C. Popescu, Edward N. Taylor, Richard Tuffs, Marina Vika, Benedetta Vulcani Nov 2015

Galaxy And Mass Assembly (Gama) : The Wavelength Dependence Of Galaxy Structure Versus Redshift And Luminosity., Rebecca Kennedy, Steven P. Bamford, Ivan K. Baldry, Boris Haußler, Benne W. Holwerda, Andrew M. Hopkins, Lee S. Kelvin, Rebecca Lange, Amanda J. Moffett, Cristina C. Popescu, Edward N. Taylor, Richard Tuffs, Marina Vika, Benedetta Vulcani

Faculty and Staff Scholarship

We study how the sizes and radial profiles of galaxies vary with wavelength, by fitting Sersic ´ functions simultaneously to imaging in nine optical and near-infrared bands. To quantify the wavelength dependence of effective radius we use the ratio, R, of measurements in two rest-frame bands. The dependence of Sersic index on wavelength, ´ N , is computed correspondingly. Vulcani et al. have demonstrated that different galaxy populations present sharply contrasting behaviour in terms of R and N . Here we study the luminosity dependence of this result. We find that at higher luminosities, early-type galaxies display a more substantial …


A Comparative Study Of Faecal Sludge Management In Malawi And Zambia: Status, Challenges And Opportunities In Pit Latrine Emptying, Rochelle H. Holm, James Madalitso Tembo, Bernard Thole Nov 2015

A Comparative Study Of Faecal Sludge Management In Malawi And Zambia: Status, Challenges And Opportunities In Pit Latrine Emptying, Rochelle H. Holm, James Madalitso Tembo, Bernard Thole

Faculty and Staff Scholarship

This review paper covers the issues of pit latrine emptying national policies and regulations with a focus on Malawi and Zambia. With 2.4 billion people worldwide still lacking improved sanitation facilities, developing countries need to look at policy, regulation and practice for household sanitation service provision with a new lens. What happens “next,” when improved sanitation facilities eventually become full? An emphasis on faecal sludge management has multiplied this important issue in the past few years. The authors compare the pit latrine emptying situation in Malawi and Zambia with a focus on status, challenges and opportunities. To build this comparison, …


Should Fixing These Failures Be Delegated To Automated Program Repair?, Le Dinh Xuan Bach, Le Bui Tien Duy, David Lo Nov 2015

Should Fixing These Failures Be Delegated To Automated Program Repair?, Le Dinh Xuan Bach, Le Bui Tien Duy, David Lo

Research Collection School Of Computing and Information Systems

Program repair constitutes one of the major components of software maintenance that usually incurs a significant cost in software production. Automated program repair is supposed to help in reducing the software maintenance cost by automatically fixing software defects. Despite the recent advances in automated software repair, it is still very costly to wait for repair tools to produce valid repairs of defects. This paper addresses the following question: "Will an automated program repair technique find a repair for a defect within a reasonable time?". To answer this question, we build an oracle that can predict whether fixing a failure should …


Not All Trips Are Equal: Analyzing Foursquare Check-Ins Of Trips And City Visitors, Wen Haw Chong, Bingtian Dai, Ee Peng Lim Nov 2015

Not All Trips Are Equal: Analyzing Foursquare Check-Ins Of Trips And City Visitors, Wen Haw Chong, Bingtian Dai, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Location-Based Social Networks (LBSN) such as Foursquare allow users to indicate venue visits via check-ins. This results in much fine grained context-rich data, useful for studying user mobility. In this work, we use check-ins to characterize trips and visitors to two cities, where visitors are defined as having their home cities elsewhere. First, we divide trips into two duration types: long and short. We then show that trip types differ in check-in distributions over venue categories, time slots, as well as check-in intensity. Based on the trip types, we then divide visitors into long-term and short-term visitors. We compare visitor …


Modelling Cascades Over Time In Microblogs, Xie Wei, Feida Zhu, Siyuan Liu, Ke Wang Nov 2015

Modelling Cascades Over Time In Microblogs, Xie Wei, Feida Zhu, Siyuan Liu, Ke Wang

Research Collection School Of Computing and Information Systems

One of the most important features of microblogging services such as Twitter is how easy it is to re-share a piece of information across the network through various user connections, forming what we call a "cascade". Business applications such as viral marketing have driven a tremendous amount of research effort predicting whether a certain cascade will go viral. Yet the rarity of viral cascades in real data poses a challenge to all existing prediction methods. One solution is to simulate cascades that well fit the real viral ones, which requires our ability to tell how a certain cascade grows over …


Analysis Of Aspects And Star Ratings In Consumer Reviews, Maruthi Prithivirajan, Vivian Lai, Kyong Jin Shim Nov 2015

Analysis Of Aspects And Star Ratings In Consumer Reviews, Maruthi Prithivirajan, Vivian Lai, Kyong Jin Shim

Research Collection School Of Computing and Information Systems

This paper presents an analysis of star ratings in consumer reviews in Yelp, an online social platform for sharing consumer reviews about local businesses. In particular, we analyze consumer reviews about food businesses. We analyze how well or poorly the star ratings (on a scale of one star to five stars) associated with these reviews tally with the sentiment derived from the textual portion of the consumer review.


Security And Privacy Of Electronic Health Information Systems: Editorial, Elisa Bertino, Robert H. Deng, Xinyi Huang, Jianying Zhou Nov 2015

Security And Privacy Of Electronic Health Information Systems: Editorial, Elisa Bertino, Robert H. Deng, Xinyi Huang, Jianying Zhou

Research Collection School Of Computing and Information Systems

Digital technologies have dramatically transformed our daily lives by bringing countless conveniences and benefits. As an evolving concept, electronic health information has become the focus of attention in both academia and industry. By leveraging modern digital technologies like the internet and the cloud, electronic health information systems will be a key enabling technology in improving the quality and convenience of patient care, encouraging patient participation in their care, reducing medical errors, improving practice efficiencies, and saving time and cost. The complexity of electronic health information systems, however, raises several new security and privacy issues. It is thus critical to investigate …


Deep Multimodal Learning For Affective Analysis And Retrieval, Lei Pang, Shiai Zhu, Chong-Wah Ngo Nov 2015

Deep Multimodal Learning For Affective Analysis And Retrieval, Lei Pang, Shiai Zhu, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Social media has been a convenient platform for voicing opinions through posting messages, ranging from tweeting a short text to uploading a media file, or any combination of messages. Understanding the perceived emotions inherently underlying these user-generated contents (UGC) could bring light to emerging applications such as advertising and media analytics. Existing research efforts on affective computation are mostly dedicated to single media, either text captions or visual content. Few attempts for combined analysis of multiple media are made, despite that emotion can be viewed as an expression of multimodal experience. In this paper, we explore the learning of highly …


Automating The Performance Deviation Analysis For Multiple System Releases: An Evolutionary Study, Felipe Pinto, Uirá Kulesza, Christoph Treude Nov 2015

Automating The Performance Deviation Analysis For Multiple System Releases: An Evolutionary Study, Felipe Pinto, Uirá Kulesza, Christoph Treude

Research Collection School Of Computing and Information Systems

This paper presents a scenario-based approach for the evaluation of the quality attribute of performance, measured in terms of execution time (response time). The approach is implemented by a framework that uses dynamic analysis and repository mining techniques to provide an automated way for revealing potential sources of performance degradation of scenarios between releases of a software system. The approach defines four phases: (i) preparation – choosing the scenarios and preparing the target releases; (ii) dynamic analysis – determining the performance of scenarios and methods by calculating their execution time; (iii) degradation analysis – processing and comparing the results of …


Determination Of Nanoparticle Localisation Within Subcellular Organelles In Vitro Using Raman Spectroscopy, Esen Efeoglu, Mark Keating, Jennifer Mcintyre, Alan Casey, Hugh Byrne Nov 2015

Determination Of Nanoparticle Localisation Within Subcellular Organelles In Vitro Using Raman Spectroscopy, Esen Efeoglu, Mark Keating, Jennifer Mcintyre, Alan Casey, Hugh Byrne

Articles

Ease of sample preparation, narrow spectral bandwidth and minimal influence from water are features of Raman spectroscopy which make it a powerful, label-free way to study a wide range of biological structures and phenomena. In this context, given the concerns over their toxicology arising from their increased production and use, evaluation of nanoparticle uptake and localisation in biological systems and determination of the mechanisms of subcellular interaction and trafficking can provide long-term solutions for nanotoxicology, and potential strategies for nanomedicine. In this study, Raman spectroscopy is explored to monitor the sequential trafficking of nanoparticles through subcellular organelles in-vitro and to …


Investigating The Role Of Shape On The Biological Impact Of Gold Nanoparticles In Vitro, Furong Tian, Hugh Byrne, Joao Conde, Tobias Stoeger, Martin Clift,, Alan Casey, Pablo Del Pino, Beatriz Pelaz, Barbara Rothen-Rutishauser,, Giovani Estrada, Jesús De La Fuente Nov 2015

Investigating The Role Of Shape On The Biological Impact Of Gold Nanoparticles In Vitro, Furong Tian, Hugh Byrne, Joao Conde, Tobias Stoeger, Martin Clift,, Alan Casey, Pablo Del Pino, Beatriz Pelaz, Barbara Rothen-Rutishauser,, Giovani Estrada, Jesús De La Fuente

Articles

Aim: To investigate the influence of gold nanoparticle (GNP) geometry on the biochemical response of Calu-3 epithelial cells.

Materials and Methods: Spherical, triangular and hexagonal GNPs were used. The GNP-cell interaction was assessed via atomic absorption spectroscopy (AAS) and transmission electron microscopy (TEM). The biochemical impact of GNPs was determined over 72hrs at [0.0001-1mg/mL].

Results: At 1mg/mL, hexagonal GNPs reduced Calu-3 viability below 60%, showed increased reactive oxygen species production and higher expression of pro-apoptotic markers. A cell mass burden of 1:2:12 as well as number of GNPs per cell (2:1:3) was observed for spherical:triangular:hexagonal GNPs.

Conclusion:

These findings do …


Raman Spectroscopy For Screening And Diagnosis Of Cervical Cancer, Fiona Lyng, Damien Traynor, Ines Rm Ramos, Franck Bonnier, Hugh Byrne Nov 2015

Raman Spectroscopy For Screening And Diagnosis Of Cervical Cancer, Fiona Lyng, Damien Traynor, Ines Rm Ramos, Franck Bonnier, Hugh Byrne

Articles

Cervical cancer is the fourth most common cancer in women worldwide and mainly affects younger women. The mortality associated with cervical cancer can be reduced if this disease is detected at the pre-cancer stage. Current gold standard methods include cytopathology, HPV testing and histopathology but these methods are limited in terms of subjectivity, cost and time. There is an unmet clinical need for new methods to aid clinicians in the early detection of cervical pre-cancer. These methods should be objective, rapid and require minimal sample preparation. Raman spectroscopy is a vibrational spectroscopic technique by which incident radiation is used to …


Genomic And Transcriptomic Evidence For Scavenging Of Diverse Organic Compounds By Widespread Deep-Sea Archaea, Meng Li, Brett J. Baker, Karthik Anantharaman, Sunit Jain, John A. Breier, Gregory J. Dick Nov 2015

Genomic And Transcriptomic Evidence For Scavenging Of Diverse Organic Compounds By Widespread Deep-Sea Archaea, Meng Li, Brett J. Baker, Karthik Anantharaman, Sunit Jain, John A. Breier, Gregory J. Dick

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Microbial activity is one of the most important processes to mediate the flux of organic carbon from the ocean surface to the seafloor. However, little is known about the microorganisms that underpin this key step of the global carbon cycle in the deep oceans. Here we present genomic and transcriptomic evidence that five ubiquitous archaeal groups actively use proteins, carbohydrates, fatty acids and lipids as sources of carbon and energy at depths ranging from 800 to 4,950 m in hydrothermal vent plumes and pelagic background seawater across three different ocean basins. Genome-enabled metabolic reconstructions and gene expression patterns show that …


The Nanograv Nine-Year Data Set: Observations Arrival Time Measurements And Analysis Of 37 Millisecond Pulsars, Z. Arzoumanian, Zaven Arzoumanian, Adam Brazier, Sarah Burke-Spolaor, Sydney Chamberlin, Shami Chatterjee, Brian Christy, James M. Cordes, Neil Cornish, Fredrick A. Jenet, Jing Luo Nov 2015

The Nanograv Nine-Year Data Set: Observations Arrival Time Measurements And Analysis Of 37 Millisecond Pulsars, Z. Arzoumanian, Zaven Arzoumanian, Adam Brazier, Sarah Burke-Spolaor, Sydney Chamberlin, Shami Chatterjee, Brian Christy, James M. Cordes, Neil Cornish, Fredrick A. Jenet, Jing Luo

Physics and Astronomy Faculty Publications and Presentations

We present high-precision timing observations spanning up to nine years for 37 millisecond pulsars monitored with the Green Bank and Arecibo radio telescopes as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We describe the observational and instrumental setups used to collect the data, and methodology applied for calculating pulse times of arrival; these include novel methods for measuring instrumental offsets and characterizing low signal-to-noise ratio timing results. The time of arrival data are fit to a physical timing model for each source, including terms that characterize time-variable dispersion measure and frequency-dependent pulse shape evolution. In …


The Fraud Detection Triangle: A New Framework For Selecting Variables In Fraud Detection Research, Adrian Gepp, Kuldeep Kumar, Sukanto Bhattacharya Oct 2015

The Fraud Detection Triangle: A New Framework For Selecting Variables In Fraud Detection Research, Adrian Gepp, Kuldeep Kumar, Sukanto Bhattacharya

Adrian Gepp

The selection of explanatory (independent) variables is crucial to developing a fraud detection model. However, the selection process in prior financial statement fraud detection studies is not standardized. Furthermore, the categories of variables differ between studies. Consequently, the new Fraud Detection Triangle framework is proposed as an overall theory to assist in guiding the selection of variables for future fraud detection research. This new framework adapts and extends Cressey’s (1953) well-known and widely-used fraud triangle to make it more suited for use in fraud detection research. While the new framework was developed for financial statement fraud detection, it is more …


2014-15 Central West State Of The Environment Report, Neil Dufty Oct 2015

2014-15 Central West State Of The Environment Report, Neil Dufty

Neil Dufty

A State of the Environment (SoE) Report is an important management tool which aims to provide the community and Council with information on the condition of the environment in the local area to assist in decision-making. Since 2007, 17 local Councils of the Greater Central West Region of NSW (Australia) have joined to produce Regional SoE Reports as part of Council reporting requirements. Recent changes to NSW legislation mean that Councils are no longer required to produce SoE Reports each year, but only once every four years, in the year of the Council election (which will next be in 2016). …


Flexible Penalized Regression For Functional Data...And Other Complex Data Objects, Philip T. Reiss Oct 2015

Flexible Penalized Regression For Functional Data...And Other Complex Data Objects, Philip T. Reiss

Philip T. Reiss

No abstract provided.


Local And Distributed Pib Accumulation Associated With Development Of Preclinical Alzheimer's Disease, Matthew R. Brier, John E. Mccarthy, Tammie L.S. Benzinger, Ari Stern, Yi Su, Karl A. Friedrichsen, John C. Morris, Beau M. Ances, Andrei G. Vlassenko Oct 2015

Local And Distributed Pib Accumulation Associated With Development Of Preclinical Alzheimer's Disease, Matthew R. Brier, John E. Mccarthy, Tammie L.S. Benzinger, Ari Stern, Yi Su, Karl A. Friedrichsen, John C. Morris, Beau M. Ances, Andrei G. Vlassenko

Mathematics Faculty Publications

Amyloid-beta plaques are a hallmark of Alzheimer's disease (AD) that can be assessed by amyloid imaging (e.g., Pittsburgh B compound [PiB]) and summarized as a scalar value. Summary values may have clinical utility but are an average over many regions of interest, potentially obscuring important topography. This study investigates the longitudinal evolution of amyloid topographies in cognitively normal older adults who had normal (N = 131) or abnormal (N = 26) PiB scans at baseline. At 3 years follow-up, 16 participants with a previously normal PiB scan had conversion to PiB scans consistent with preclinical AD. We investigated the multivariate …


P-38 On The Riemannian Submersion Invariant, Yun Myung Oh Oct 2015

P-38 On The Riemannian Submersion Invariant, Yun Myung Oh

Celebration of Research and Creative Scholarship

For a Riemannian submersion pi:Mn->Bbwith totally geodesic fibers, the submersion invariant (see attached abstract for equation) was introduced using the integrability tensor of the submersion. B. Y. Chen has provided the inequality on this invariant if the manifold M admits an isometric immersion into a Riemannian manifold Mm. Some of the recent results on this invariant are included with examples. This is a continuation of the work published in 2013.

See attached abstract for full equations.


Photometric Study Of The Short-Period Eclipsing Binary V441 Lac, Daimei Wang, Liyun Zhang, Xianming Han, Franz Agerer, Qingfeng Pi, Shuai Wang Oct 2015

Photometric Study Of The Short-Period Eclipsing Binary V441 Lac, Daimei Wang, Liyun Zhang, Xianming Han, Franz Agerer, Qingfeng Pi, Shuai Wang

Xianming Han

We present the first multi-color VRI CCD light curves of a short-period eclipsing binary star v441 Lac in this paper. We obtained our light curves on Oct. 4 and 8, 2013 at Xinglong station of National Astronomical Observatories, China. We updated the ephemeris of V441 Lac based on three new minima derived by our new observational data together with previously available light curve minima. By fitting the O−C (observed minus calculated) values of the minima, we found that the orbital period of V441 Lac exhibits an increasing trend of Ṗ=5.67(0.35)×10^-7 days/year, which might be explained by mass transfer from the …


Magnetic-Field-Induced Alignment-To-Orientation Conversion In Sodium, G. Schinn, Xianming Han Oct 2015

Magnetic-Field-Induced Alignment-To-Orientation Conversion In Sodium, G. Schinn, Xianming Han

Xianming Han

We report a detailed investigation of excited-state alignment-to-orientation conversion in the presence of an external magnetic field. This counterintuitive phenomenon occurs under intermediate-coupling conditions. A weak, linearly polarized, cw laser beam was used to excite and align the Na 3P3/2 state in an atomic beam along the z direction. The degree of circular polarization of the resulting fluorescence was detected along the z direction as a function of magnetic-field strength. The spectrally integrated transitions originating from individual F levels of the 3S1/2 state yield a maximum circular-polarization fraction of ∼40%; integrating the circular polarization over all the allowed 3S1/2-3P3/2 transitions …


Differential, Partial Cross Sections For Electron Excitation Of The Sodium 3p State, Xianming Han, G. W. Schwinn, A. Gallagher Oct 2015

Differential, Partial Cross Sections For Electron Excitation Of The Sodium 3p State, Xianming Han, G. W. Schwinn, A. Gallagher

Xianming Han

Using a powerful laser-based experimental method, the cross section for electron excitation of Na(3S) atoms to the Na(3P) state has been decomposed into partial components with respect to changes in the spin and angular momentum of the atomic electron, and these partial cross sections are further reduced to their differential character with respect to the electron scattering angle. Partial, differential cross sections are reported for electron collision energies from threshold 2.1 to 3.6 eV, and compared to available calculations.