Physical Sciences and Mathematics Commons^™

Search For Anisotropic Gravitational-Wave Backgrounds Using Data From Advanced Ligo And Advanced Virgo's First Three Observing Runs, R. Abbott, T. D. Abbott, S. Abraham, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report results from searches for anisotropic stochastic gravitational-wave backgrounds using data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. For the first time, we include Virgo data in our analysis and run our search with a new efficient pipeline called pystoch on data folded over one sidereal day. We use gravitational-wave radiometry (broadband and narrow band) to produce sky maps of stochastic gravitational-wave backgrounds and to search for gravitational waves from point sources. A spherical harmonic decomposition method is employed to look for gravitational-wave emission from spatially-extended sources. Neither technique found evidence of …

Search For Anisotropic Gravitational-Wave Backgrounds Using Data From Advanced Ligo And Advanced Virgo's First Three Observing Runs, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, D. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, T. Akutsu, Tiffany Z. Summerscales

Faculty Publications

We report results from searches for anisotropic stochastic gravitational-wave backgrounds using data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. For the first time, we include Virgo data in our analysis and run our search with a new efficient pipeline called pystoch on data folded over one sidereal day. We use gravitational-wave radiometry (broadband and narrow band) to produce sky maps of stochastic gravitational-wave backgrounds and to search for gravitational waves from point sources. A spherical harmonic decomposition method is employed to look for gravitational-wave emission from spatially-extended sources. Neither technique found evidence of …

Upper Limits On The Isotropic Gravitational-Wave Background From Advanced Ligo And Advanced Virgo’S Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales

Faculty Publications

We report results of a search for an isotropic gravitational-wave background (GWB) using data from Advanced LIGO’s and Advanced Virgo’s third observing run (O3) combined with upper limits from the earlier O1 and O2 runs. Unlike in previous observing runs in the advanced detector era, we include Virgo in the search for the GWB. The results of the search are consistent with uncorrelated noise, and therefore we place upper limits on the strength of the GWB. We find that the dimensionless energy density ΩGW≤5.8×10−9 at the 95% credible level for a flat (frequency-independent) GWB, using a prior which is uniform …

Synoptic Conditions And Potential Causes Of The Extreme Heavy Rainfall Event Of January 2009 Over Mindanao Island, Philippines, Lyndon Mark P. Olaguera, Michelle Español Caballar, Joseph Cabacungan De Mata, Loida Ann Torres Dagami, Jun Matsumoto, Hisayuki Kubota

Physics Faculty Publications

This study investigates the synoptic conditions that led to the heavy rainfall/flood (HRF) event in Mindanao Island, Philippines (122 −127°E; 5 −10°N), on January 2009 (JAN2009 HRF) that are less emphasized in previous works. Extensive flooding was reported over Cagayan de Oro City in the northern part of Mindanao, where the rainfall on January 10, 11, and 13, 2009, exceeded the 99th percentile of daily rainfall records of all January of the city from 1979 to 2017 by almost two times. A similar exceedance was also felt in Hinatuan station over the eastern coast of Mindanao Island on January 15, …

Investigation And Statistical Modeling Of The Mechanical Properties Of Additively Manufactured Lattices, Derek G. Spear, Anthony N. Palazotto

Faculty Publications

This paper describes the background, test methodology, and experimental results associated with the testing and analysis of quasi-static compression testing of additively manufactured open-cell lattice structures. The study aims to examine the effect of lattice topology, cell size, cell density, and surface thickness on the mechanical properties of lattice structures. Three lattice designs were chosen, the Diamond, I-WP, and Primitive Triply Periodic Minimal Surfaces (TPMSs). Uniaxial compression tests were conducted for every combination of the three lattice designs, three cell sizes, three cell densities, and three surface thicknesses. In order to perform an efficient experiment and gain the most information …

Months-Long Spike In Aqueous Arsenic Following Domestic Well Installation And Disinfection: Short- And Long-Term Drinking Water Quality Implications, M. L. Erickson, E. D. Swanner, Brady A. Ziegler, J. R. Havig

Geosciences Faculty Research

Exposure to high concentration geogenic arsenic via groundwater is a worldwide health concern. Well installation introduces oxic drilling fluids and hypochlorite (a strong oxidant) for disinfection, thus inducing geochemical disequilibrium. Well installation causes changes in geochemistry lasting 12 + months, as illustrated in a recent study of 250 new domestic wells in Minnesota, north-central United States. One study well had extremely high initial arsenic (1550 µg/L) that substantially decreased after 15 months (5.2 µg/L). The drilling and development of the study well were typical and ordinary; nothing observable indicated the very high initial arsenic concentration. We hypothesized that oxidation of …

Upper Limits On The Isotropic Gravitational-Wave Background From Advanced Ligo And Advanced Virgo's Third Observing Run, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, D. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, T. Akutsu, K. M. Aleman, Tiffany Summerscales

Faculty Publications

We report results of a search for an isotropic gravitational-wave background (GWB) using data from Advanced LIGO's and Advanced Virgo's third observing run (O3) combined with upper limits from the earlier O1 and O2 runs. Unlike in previous observing runs in the advanced detector era, we include Virgo in the search for the GWB. The results of the search are consistent with uncorrelated noise, and therefore we place upper limits on the strength of the GWB. We find that the dimensionless energy density ωGW≤5.8×10-9 at the 95% credible level for a flat (frequency-independent) GWB, using a prior which is uniform …

Search For Anisotropic Gravitational-Wave Backgrounds Using Data From Advanced Ligo And Advanced Virgo’S First Three Observing Runs, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales

Faculty Publications

We report results from searches for anisotropic stochastic gravitational-wave backgrounds using data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. For the first time, we include Virgo data in our analysis and run our search with a new efficient pipeline called pystoch on data folded over one sidereal day. We use gravitational-wave radiometry (broadband and narrow band) to produce sky maps of stochastic gravitational-wave backgrounds and to search for gravitational waves from point sources. A spherical harmonic decomposition method is employed to look for gravitational-wave emission from spatially-extended sources. Neither technique found evidence of …

Protistan Grazing Impacts Microbial Communities And Carbon Cycling At Deep-Sea Hydrothermal Vents, Sarah K. Hu, Erica L. Herrera, Amy R. Smith, Maria G. Pachiadaki, Virginia P. Edgcomb, Sean P. Sylva, Eric W. Chan, Jeffrey S. Seewald, Christopher R. German, Julie A. Huber

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

Microbial eukaryotes (or protists) in marine ecosystems are a link between primary producers and all higher trophic levels, and the rate at which heterotrophic protistan grazers consume microbial prey is a key mechanism for carbon transport and recycling in microbial food webs. At deep-sea hydrothermal vents, chemosynthetic bacteria and archaea form the base of a food web that functions in the absence of sunlight, but the role of protistan grazers in these highly productive ecosystems is largely unexplored. Here, we pair grazing experiments with a molecular survey to quantify protistan grazing and to characterize the composition of vent-associated protists in …

The Non-Backtracking Spectrum Of A Graph And Non-Bactracking Pagerank, Cory Glover

Theses and Dissertations

This thesis studies two problems centered around non-backtracking walks on graphs. First, we analyze the spectrum of the non-backtracking matrix of a graph. We show how to obtain the eigenvectors of the non-backtracking matrix using a smaller matrix and in doing so, create a block diagonal decomposition which more clearly expresses the non-backtracking matrix eigenvalues. Additionally, we develop upper and lower bounds on the matrix spectrum and use the spectrum to investigate properties of the graph. Second, we investigate the difference between PageRank and non-backtracking PageRank. We show some instances where there is no difference and develop an algorithm to …

Simulating Cambrian Climate: The Significance Of Atmospheric Co2 Concentration And Continental Position, Grace Cutting

Ursidae: The Undergraduate Research Journal at the University of Northern Colorado

The Cambrian Period began approximately 541 million years ago, and is known for the “Cambrian Explosion”, a time when multicellular life began to rapidly diversify. There is natural historic evidence (isotopes, rock formations, and fossils) that suggests the Cambrian Period experienced a warm climate. However, there is also conflicting evidence that the Cambrian climate may have undergone freezing and thawing cycles, with ice possibly present near the equator. It is critical to understand how ecosystems were able to adapt to past climate changes, especially when analyzing the impacts of modern human activity on climate. Climate model simulations were run to …

An Analysis Of Effort, Success, And Attitudes Of Louisiana Hunters By Email And Mixed-Mode Surveys, Michael Sullivan

LSU Master's Theses

ABSTRACT

Louisiana surveys waterfowl hunters every 5 years to assess harvest, harvest practices, demographics, and specific management objectives, as well as to research hypotheses derived from previous surveys of waterfowl hunters. In the 2020 survey, research hypotheses addressed hunter perceptions of changing waterfowl migration patterns, satisfaction, and relationships between perceptions and avidity with survey distribution waves and sample coverage. I surveyed a stratified census of 68,578 Louisiana waterfowl hunters by email following the 2019–2020 season, and asked 31 questions about waterfowl-hunting effort, success, satisfaction, regulatory alternatives, and demographics. I used generalized linear models to test hypotheses about hunters’ perception of …

Do Different Relevance Attributes Indicate The Same Conservation Priorities? A Case Study In Caves Of Southeastern Brazil, Maysa F.V.R. Souza, Denizar A. Alvarenga, Marconi Souza-Silva, Rodrigo L. Ferreira

International Journal of Speleology

In the last decade, the scientific community brought to the debate gaps that slow down the advance of knowledge regarding global biodiversity. More recently, this discussion has reached subterranean environments, where these gaps are even more dramatic due to the relict and vulnerable nature of their species. In this context, we tested ecological metrics related to some of these gaps, checking if the biological relevance of the caves would change depending on ecological attributes related to each metric. The study was carried out in caves from southeastern Brazil, located in a region presenting a high richness of troglobitic species restricted …

The Decline Of Transhumance In The West And The Implications For Private Grazing Lands: California Case Studies, Lynn Huntsinger, Larry C. Forero, Adriana Sulak

IGC Proceedings (1993-2023)

No abstract provided.

The Use Of Sustainable Agronomic Practices And Grazing To Manage Organic Olive Orchards In Western Australia, C. Faiello, Andrea Pardini, L. Litjens

IGC Proceedings (1993-2023)

No abstract provided.

Whether Or Not To Continue The Communal Land Practices? — The Comparative Case Studies Of Two Tibetan Villages In The Qinghai‐Tibet Plateau, Yongping Yang, Yao Fu

IGC Proceedings (1993-2023)

No abstract provided.

Cultivation In China Grassland: Angel Or Devil?, L. Yang, X Y. Hou

IGC Proceedings (1993-2023)

No abstract provided.

Downscaling Of Far-Red Solar-Induced Chlorophyll Fluorescence Of Different Crops From Canopy To Leaf Level Using A Diurnal Data Set Acquired By The Airborne Imaging Spectrometer Hyplant, Bastian Siegmann, Maria Pilar Cendrero-Mateo, Sergio Cogliati, Alexander Damm, John Gamon, David Herrera, Christopehr Jedmowski, Laura Verena Junker-Frohn, Thorsten Kraska, Onno Muller, Patrick Rademske, Christiaan Van Der Tol, Juan Quiros-Vargas, Peiqi Yang, Uwe Rascher

School of Natural Resources: Faculty Publications

Remote sensing-based measurements of solar-induced chlorophyll fluorescence (SIF) are useful for assessing plant functioning at different spatial and temporal scales. SIF is the most direct measure of photosynthesis and is therefore considered important to advance capacity for the monitoring of gross primary production (GPP) while it has also been suggested that its yield facilitates the early detection of vegetation stress. However, due to the influence of different confounding effects, the apparent SIF signal measured at canopy level differs from the fluorescence emitted at leaf level, which makes its physiological interpretation challenging. One of these effects is the scattering of SIF …

Photovoltages In Polycrystalline Mosaic Solar Cells, Steluta A. Dinca, Eric A. Schiff

Chemistry - All Scholarship

In some thin-film solar cells the light-absorbing layer is a mosaic of crystalline grains whose boundaries run from the back to the front of the cell. We used the semiconductor modeling software Sesame to do numerical calculations of the optoelectronic properties of such cells assuming that recombination of minority photocarriers occurs primarily at the grain boundaries. The work complements analytical results for diffusion-limited recombination at grain boundaries and dislocations. We chose idealized n-CdS/p-CdTe solar cells for illustration. We find that the open-circuit voltage, V_oc, under illumination declines logarithmically with increasing ratio D/θ², where D is the …

Comparative Study Of Leachate Characterization: Implication For Sustainable Environmental Management, Osakpolor Marvellous Omorogieva, Victory Itua Igberase

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

Understanding the sources of environmental stressors, the role of geology, climate and technology would provide a guide to solving the problems posed by such stressor. The study examine the sources of wastes in Ikhueniro open dumpsite located in Benin city, Nigeria and characterize the leachate emanating from it. This will assist in adequate design of managerial scheme to tackle the menace posed by it while putting into consideration the role of geology, climate and technology. The key objectives are to carry out field study, characterize wastes in the dumpsite and collect raw leachate emanating from the wastes heap in order …

Understanding Covid-19 Dynamics And The Effects Of Interventions In The Philippines: A Mathematical Modelling Study, Jamie M. Caldwell, Elvira P. De Lara-Tuprio, Timothy Robin Y. Teng, Ma. Regina Justina E. Estuar, Raymond Francis R. Sarmiento, Milinda Abayawardana B. Eng, Robert Neil F. Leong, Richard T. Gray, James G. Wood, Linh-Vi Le, Emma S. Mcbryde, Romain Ragonnet, James M. Trauer

Mathematics Faculty Publications

Background

COVID-19 initially caused less severe outbreaks in many low- and middle-income countries (LMIC) compared with many high-income countries; possibly because of differing demographics; socioeconomics; surveillance; and policy responses. Here; we investigate the role of multiple factors on COVID-19 dynamics in the Philippines; a LMIC that has had a relatively severe COVID-19 outbreak.

Methods

We applied an age-structured compartmental model that incorporated time-varying mobility; testing; and personal protective behaviors (through a “Minimum Health Standards” policy; MHS) to represent the first wave of the Philippines COVID-19 epidemic nationally and for three highly affected regions (Calabarzon; Central Visayas; and the National Capital …

Service Quality Monitoring In Confined Spaces Through Mining Twitter Data, Mohammad Masoud Rahimi, Elham Naghizade, Mark Stevenson, Stephan Winter

Journal of Spatial Information Science

Promoting public transport depends on adapting effective tools for concurrent monitoring of perceived service quality. Social media feeds, in general, provide an opportunity to ubiquitously look for service quality events, but when applied to confined geographic area such as a transport node, the sparsity of concurrent social media data leads to two major challenges. Both the limited number of social media messages--leading to biased machine-learning--and the capturing of bursty events in the study period considerably reduce the effectiveness of general event detection methods. In contrast to previous work and to face these challenges, this paper presents a hybrid solution based …

The Impact Of Urban Road Network Morphology On Pedestrian Wayfinding Behaviour, Debjit Bhowmick, Stephan Winter, Mark Stevenson, Peter Vortisch

Journal of Spatial Information Science

During wayfinding pedestrians do not always choose the shortest available route. Instead, route choices are guided by several well-known wayfinding strategies or heuristics. These heuristics minimize cognitive effort and usually lead to satisfactory route choices. Our previous study evaluated the costs of four well-known pedestrian wayfinding heuristics and their variation across nine network morphologies. It was observed that the variation in the cost of these wayfinding heuristics increased with an increase in the irregularity of the network, indicating that people may opt for more diverse heuristics while walking through relatively regular networks, and may prefer specific heuristics in the relatively …

How Does Socio-Economic And Demographic Dissimilarity Determine Physical And Virtual Segregation?, Michael Dorman, Tal Svoray, Itai Kloog

Journal of Spatial Information Science

It is established that socio-economic and demographic dissimilarities between populations are determinants of spatial segregation. However, the understanding of how such dissimilarities translate into actual segregation is limited. We propose a novel network-analysis approach to comprehensively study the determinants of communicative and mobility-related spatial segregation, using geo-tagged Twitter data. We constructed weighted spatial networks representing tie strength between geographical areas, then modeled tie formation as a function of socio-economic and demographic dissimilarity between areas. Physical and virtual tie formation were affected by income, age, and race differences, although these effects were smaller by an order of magnitude than the geographical …

Geocomputation 2019 Special Feature, Antoni Moore, Mark Gahegan

Journal of Spatial Information Science

No abstract provided.

Modelling Orebody Structures: Block Merging Algorithms And Block Model Spatial Restructuring Strategies Given Mesh Surfaces Of Geological Boundaries, Raymond Leung

Journal of Spatial Information Science

This paper describes a framework for capturing geological structures in a 3D block model and improving its spatial fidelity, including the correction of stratigraphic, mineralisation and other types of boundaries, given new mesh surfaces. Using surfaces that represent geological boundaries, the objectives are to identify areas where refinement is needed, increase spatial resolution to minimise surface approximation error, reduce redundancy to increase the compactness of the model and identify the geological domain on a block-by-block basis. These objectives are fulfilled by four system components which perform block-surface overlap detection, spatial structure decomposition, sub-blocks consolidation and block tagging, respectively. The main …

Big Issues For Big Data: Challenges For Critical Spatial Data Analytics, Chris Brunsdon, Alexis Comber

Journal of Spatial Information Science

In this paper we consider some of the issues of working with big data and big spatial data and highlight the need for an open and critical framework. We focus on a set of challenges underlying the collection and analysis of big data. In particular, we consider 1) inference when working with usually biased big data, challenging the assumed inferential superiority of data with observations, n, approaching N, the population n -> N. We also emphasise 2) the need for analyses that answer questions of practical significance or with greater emphasis on the size of the effect, rather than the …

Route Schematization With Landmarks, Marcelo De Lima Galvao, Jakub Krukar, Martin Noellenburg, Angela Schwering

Journal of Spatial Information Science

Predominant navigation applications make use of a turn-by-turn instructions approach and are mostly supported by small screen devices. This combination does little to improve users' orientation or spatial knowledge acquisition. Considering this limitation, we propose a route schematization method aimed for small screen devices to facilitate the readability of route information and survey knowledge acquisition. Current schematization methods focus on the route path and ignore context information, specially polygonal landmarks (such as lakes, parks, and regions), which is crucial for promoting orientation. Our schematization method, in addition to the route path, takes as input: adjacent streets, point-like landmarks, and polygonal …

Local Modelling: One Size Does Not Fit All, A. Stewart Fotheringham

Journal of Spatial Information Science

This editorial piece considers what happens when we abandon the concept that models of social processes have global application in favor of a local approach in which context or the influence of 'place' has an important role. A brief history of this local approach to statistical modelling is given, followed by a consideration of its ramifications for understanding societal issues. The piece concludes with futures challenges and prospects in this area.

Indigeneity And Spatial Information Science, Matt Duckham, Serene Ho

Journal of Spatial Information Science

Spatial information science has given rise to a set of concepts, tools, and techniques for understanding our geographic world. In turn, the technologies built on this body of knowledge embed certain ways of knowing." This vision paper traces the roots and impacts of those embeddings and explores how they can sometimes be inherently at odds with or completely subvert Indigenous Peoples' ways of knowing. However advancements in spatial information science offer opportunities for innovation whilst working towards reconciliation. We highlight as examples four active research topics in the field to support a call to action for greater inclusion of Indigenous …