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University of Texas Rio Grande Valley

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Articles 211 - 240 of 2419

Full-Text Articles in Physical Sciences and Mathematics

A Review On Antibacterial Activity Of Nanoparticles, Badr-Edine Sadoq, Mohammed Reda Britel, Adel Bouajaj, Ramzi Maâlej, Ahmed Touhami, Marwa Abid, Hanen Douiri, Fakhita Touhami, Amal Maurady Oct 2023

A Review On Antibacterial Activity Of Nanoparticles, Badr-Edine Sadoq, Mohammed Reda Britel, Adel Bouajaj, Ramzi Maâlej, Ahmed Touhami, Marwa Abid, Hanen Douiri, Fakhita Touhami, Amal Maurady

Physics and Astronomy Faculty Publications and Presentations

The increasing resistance of bacteria to antibiotic agents is a main global public health problem. The use of nanoparticles is one of the promising ways to overcome microbial resistance to antimicrobial agents. Metal nanoparticles are increasingly used to target bacterial strains. Advances in nanotechnology, in particular the ability to synthesize nanoparticles of specific size and shape, are likely to lead to the development of new antibacterial agents. The antibacterial activities of nanoparticles are largely influenced by their sizes and large surface area/mass ratio. The antibacterial mechanisms of nanoparticles are poorly understood, but the currently accepted mechanisms include oxidative stress induction, …


A Second Homotopy Group For Digital Images, Gregory Lupton, Oleg R. Musin, Nicholas A. Scoville, P. Christopher Staecker, Jonathan Treviño-Marroquín Oct 2023

A Second Homotopy Group For Digital Images, Gregory Lupton, Oleg R. Musin, Nicholas A. Scoville, P. Christopher Staecker, Jonathan Treviño-Marroquín

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We define a second (higher) homotopy group for digital images. Namely, we construct a functor from digital images to abelian groups, which closely resembles the ordinary second homotopy group from algebraic topology. We illustrate that our approach can be effective by computing this (digital) second homotopy group for a digital 2-sphere.


Thermal Dose Inactivation Of Escherichia Coli By Magnetic Induced Hyperthermia, Silverio A. Lopez, Carlos Trevino De Leo, Ivan Davila, Karen S. Martirosyan Sep 2023

Thermal Dose Inactivation Of Escherichia Coli By Magnetic Induced Hyperthermia, Silverio A. Lopez, Carlos Trevino De Leo, Ivan Davila, Karen S. Martirosyan

Research Symposium

Background: Apoptosis of mutated cells via magnetic hyperthermia has gained advocacy as technology capable of being used in lieu of chemotherapy for targeting cancer tumors. Progress of nanotechnology offers effective remote heating of magnetic fluid via hyperthermia. The heating and specific power absorption of these nanoparticles use in the magnetic fluid are dependent on particle properties and treatment locations.

Methods: Nanoparticles were fabricated using microfluidic system by interaction of two solutions containing 2Fe(NO3)3+FeSO4 and NaOH+2%Dextran to create nanostructured media with a biocompatible dextran coating and a Fe3O4 core. The nanoparticles, of a concentration of 5mg/ml, were placed in a vile …


Precise Method To Identify Kinase Drug Targets In Complex Diseases: The First Step Towards Sustainable And Effective Treatment, Hasbanny Irisson, Marzieh Ayati Sep 2023

Precise Method To Identify Kinase Drug Targets In Complex Diseases: The First Step Towards Sustainable And Effective Treatment, Hasbanny Irisson, Marzieh Ayati

Research Symposium

Background: Kinases are enzymes that have proven to be important drug targets due to their role in critical biological mechanisms such as phosphorylation. Phosphorylation happens when a kinase catalyzes the transfer of a phosphate group to a protein in a phosphorylated site, which then becomes known as the substrate of the kinase. Any dysregulation of protein phosphorylation causes a wide range of complex diseases including cancer. Thus, discovering the links between kinases and their substrates (i.e. predicting kinase-substrate associations (KSAs)) is crucial in developing effective and sustainable treatments. Presently, less than 5% of phosphorylated sites have an associated kinase, and …


An Ngqd Based Diagnostic Tool For Pancreatic Cancer, Ryan Ketan Ajgaonkar, Bong Lee, Alina Valimukhametova, Anton Naumov, Giridhar Akkaraju Sep 2023

An Ngqd Based Diagnostic Tool For Pancreatic Cancer, Ryan Ketan Ajgaonkar, Bong Lee, Alina Valimukhametova, Anton Naumov, Giridhar Akkaraju

Research Symposium

Background: Pancreatic cancer remains difficult to detect at early stages which contributes to a poor five-yearsurvival rate. Therefore, early detection approaches based on novel technologies should be explored to address this critical health issue. Nanomaterials have recently emerged as frontrunners for diagnostic applications due to their small size in the 1-100 nm range, which facilitates one-on-one interactions with a variety of biomolecules like oligonucleotides and makes them suitable for a plethora of detection and delivery applications. In this work, the presence of specific pancreatic cancer miRNA (pre-miR-132) is detected utilizing the fluorescence properties of highly biocompatible nitrogen-doped graphene quantum dots …


Effects Of Spin-Orbit Coupling On Gravitational Waveforms From A Triaxial Nonaligned Neutron Star In A Binary System, Wen-Fan Feng, Tan Liu, Jie-Wen Che, Yan Wang, Soumya D. Mohanty Sep 2023

Effects Of Spin-Orbit Coupling On Gravitational Waveforms From A Triaxial Nonaligned Neutron Star In A Binary System, Wen-Fan Feng, Tan Liu, Jie-Wen Che, Yan Wang, Soumya D. Mohanty

Physics and Astronomy Faculty Publications and Presentations

Spinning neutron stars (NSs) can emit continuous gravitational waves (GWs) that carry a wealth of information about the compact object. If such a signal is detected, it will provide us with new insight into the physical properties of matter under extreme conditions. According to binary population synthesis simulations, future space-based GW detectors, such as LISA and TianQin, can potentially detect some double NSs in tight binaries with orbital periods shorter than 10 minutes. The possibility of a successful directed search for continuous GWs from the spinning NS in such a binary system identified by LISA/TianQin will be significantly increased with …


Search For Gravitational Waves Associated With Fast Radio Bursts Detected By Chime/Frb During The Ligo–Virgo Observing Run O3a, R. Abbott, T. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Sep 2023

Search For Gravitational Waves Associated With Fast Radio Bursts Detected By Chime/Frb During The Ligo–Virgo Observing Run O3a, R. Abbott, T. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We search for gravitational-wave (GW) transients associated with fast radio bursts (FRBs) detected by the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project, during the first part of the third observing run of Advanced LIGO and Advanced Virgo (2019 April 1 15:00 UTC–2019 October 1 15:00 UTC). Triggers from 22 FRBs were analyzed with a search that targets both binary neutron star (BNS) and neutron star–black hole (NSBH) mergers. A targeted search for generic GW transients was conducted on 40 FRBs. We find no significant evidence for a GW association in either search. Given the large uncertainties in the …


Modeling Nonsegmented Negative-Strand Rna Virus (Nnsv) Transcription With Ejective Polymerase Collisions And Biased Diffusion, Felipe-Andres Piedra Sep 2023

Modeling Nonsegmented Negative-Strand Rna Virus (Nnsv) Transcription With Ejective Polymerase Collisions And Biased Diffusion, Felipe-Andres Piedra

Research Symposium

Background: The textbook model of NNSV transcription predicts a gene expression gradient. However, multiple studies show non-gradient gene expression patterns or data inconsistent with a simple gradient. Regarding the latter, several studies show a dramatic decrease in gene expression over the last two genes of the respiratory syncytial virus (RSV) genome (a highly studied NNSV). The textbook model cannot explain these phenomena.

Methods: Computational models of RSV and vesicular stomatitis virus (VSV – another highly studied NNSV) transcription were written in the Python programming language using the Scientific Python Development Environment. The model code is freely available on GitHub: …


Self-Organization For Community Resilience In An Invisible Agricultural Community, Anna Erwin, Chelsea A. Silva, Zhao Ma Sep 2023

Self-Organization For Community Resilience In An Invisible Agricultural Community, Anna Erwin, Chelsea A. Silva, Zhao Ma

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

This study investigates how self-organizing efforts by residents of informal settlements, primarily migrant and informal farmworkers, shape community resilience in Majes, a water-scarce irrigation district in the Atacama Desert of Peru. We collected 45 semi-structured interviews with residents and authorities in Majes and analyzed findings through a framework of self-organizing. Analyses revealed that self-organizing by residents of informal settlements incorporated the three components of White’s theory of Community Agency and Community Resilience, which contends that marginalized communities increase resilience by fostering a commons praxis, practicing a prefigurative politics, and developing opportunities for economic autonomy. We also found …


Wallaby Pre-Pilot Survey: Ultra-Diffuse Galaxies In The Eridanus Supergroup, B-Q For, K. Spekkens, L. Stavely-Smith, K. Bekki, A. Karunakaran, B. Catinella, Bärbel S. Koribalski, K. Lee-Waddell, Juan P. Madrid, C. Murugeshan Sep 2023

Wallaby Pre-Pilot Survey: Ultra-Diffuse Galaxies In The Eridanus Supergroup, B-Q For, K. Spekkens, L. Stavely-Smith, K. Bekki, A. Karunakaran, B. Catinella, Bärbel S. Koribalski, K. Lee-Waddell, Juan P. Madrid, C. Murugeshan

Physics and Astronomy Faculty Publications and Presentations

We present a pilot study of the atomic neutral hydrogen gas (H I) content of ultra-diffuse galaxy (UDG) candidates. In this paper, we use the pre-pilot Eridanus field data from the Widefield ASKAP L-band Legacy All-sky Blind Survey to search for H I in UDG candidates found in the Systematically Measuring Ultra-diffuse Galaxies survey (SMUDGes). We narrow down to 78 SMUDGes UDG candidates within the maximum radial extents of the Eridanus subgroups for this study. Most SMUDGes UDGs candidates in this study have effective radii smaller than 1.5 kpc and thus fail to meet the defining size threshold. We …


Study Of Multilayer Flow Of Two Immiscible Nanofluids In A Duct With Viscous Dissipation, Jawali C. Umavathi, Mahanthesh Basavarajappa Sep 2023

Study Of Multilayer Flow Of Two Immiscible Nanofluids In A Duct With Viscous Dissipation, Jawali C. Umavathi, Mahanthesh Basavarajappa

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Numerical simulations for the mixed convective multilayer flow of two different immiscible nanofluids in a duct with viscous heating effects were performed in this study. The left and right faces of the duct are maintained to be isothermal, while other side faces are insulated. The mathematical governing system for each layer consists of an incompressibility condition equation, the Navier–Stokes momentum equation, and the conservation of energy equation. At the interface of the immiscible layer, the continuity of velocity, shear stress, temperature, and heat flux are considered. The dimensionless equations governing each layer were numerically integrated using the finite difference method …


The Taylor Resolution Over A Skew Polynomial Ring, Luigi Ferraro, Desiree Martin, W. Frank Moore Sep 2023

The Taylor Resolution Over A Skew Polynomial Ring, Luigi Ferraro, Desiree Martin, W. Frank Moore

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Let k be a field and let I be a monomial ideal in the polynomial ring Q = k[x1, . . . , xn]. In her thesis, Taylor introduced a complex which provides a finite free resolution for Q/I as a Q-module. Later, Gemeda constructed a differential graded structure on the Taylor resolution. More recently, Avramov showed that this differential graded algebra admits divided powers. We generalize each of these results to monomial ideals in a skew polynomial ring R. Under the hypothesis that the skew commuting parameters defining R are roots of unity, we prove as an application that …


Investigation Of The Thermodynamics For The Removal Of As(Iii) And As(V) From Water Using Synthesized Zno Nanoparticles And The Effects Of Ph, Temperature, And Time, Helia Magali Morales, Grecia Torreblanca, Arnulfo Mar, Mataz Alcoutlabi, Thomas Eubanks, Erik Plata, Jason Parsons Sep 2023

Investigation Of The Thermodynamics For The Removal Of As(Iii) And As(V) From Water Using Synthesized Zno Nanoparticles And The Effects Of Ph, Temperature, And Time, Helia Magali Morales, Grecia Torreblanca, Arnulfo Mar, Mataz Alcoutlabi, Thomas Eubanks, Erik Plata, Jason Parsons

Chemistry Faculty Publications and Presentations

In the present study, the removal of both As(III) and As(V) from aqueous solutions using synthesized ZnO nanomaterials was achieved. The ZnO nanomaterial was synthesized using a precipitation technique and characterized using XRD, SEM, and Raman spectroscopy. XRD confirmed the ZnO nanoparticles were present in the hexagonal wurtzite structure. SEM of the particles showed they were aggregates of triangular and spherical particles. The average nanoparticle size was determined to be 62.03 ± 4.06 nm using Scherrer’s analysis of the three largest diffraction peaks. Raman spectroscopy of the ZnO nanoparticles showed only ZnO peaks, whereas the after-reaction samples indicated that As(V) …


Draft Genome Of Methanol-Oxidizing Methylobacterium Fujisawaense Strain Lac1, Jooho Chung, Jinha Kim, John C. Blazier, Myung Hwangbo, Kung-Hui Chu Sep 2023

Draft Genome Of Methanol-Oxidizing Methylobacterium Fujisawaense Strain Lac1, Jooho Chung, Jinha Kim, John C. Blazier, Myung Hwangbo, Kung-Hui Chu

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

We report the draft genome of Methylobacterium fujisawaense LAC1 isolated from an acidic aquifer in Indian Head, MD, USA. The genome contains 5,883,000 bp and has a GC content of 70% with 5,434 protein-encoding genes with functional assignments. This strain can grow on methanol with lanthanum, a rare earth element.


Microplastics Distribution Within Western Arctic Seawater And Sea Ice, Alessandra D’Angelo, Nicole Trenholm, Brice Loose, Laura Glastra, Jacob Strock, Jongsun Kim Sep 2023

Microplastics Distribution Within Western Arctic Seawater And Sea Ice, Alessandra D’Angelo, Nicole Trenholm, Brice Loose, Laura Glastra, Jacob Strock, Jongsun Kim

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

Microplastic pollution has emerged as a global environmental concern, exhibiting wide distribution within marine ecosystems, including the Arctic Ocean. Limited Arctic microplastic data exist from beached plastics, seabed sediments, floating plastics, and sea ice. However, no studies have examined microplastics in the sea ice of the Canadian Arctic Archipelago and Tallurutiup Imanga National Marine Conservation Area, and few have explored Arctic marginal seas’ water column. The majority of the microplastic data originates from the Eurasian Arctic, with limited data available from other regions of the Arctic Ocean. This study presents data from two distinct campaigns in the Canadian Arctic Archipelago …


Multi-Symplectic Simulation On Soliton-Collision For Nonlinear Perturbed Schrödinger Equation, Peijun Zhang, Weipeng Hu, Zhen Wang, Zhijun Qiao Sep 2023

Multi-Symplectic Simulation On Soliton-Collision For Nonlinear Perturbed Schrödinger Equation, Peijun Zhang, Weipeng Hu, Zhen Wang, Zhijun Qiao

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Seeking solitary wave solutions and revealing their interactional characteristics for nonlinear evolution equations help us lot to comprehend the motion laws of the microparticles. As a local nonlinear dynamic behavior, the soliton-collision is difficult to be reproduced numerically. In this paper, the soliton-collision process in the nonlinear perturbed Schrödinger equation is simulated employing the multi-symplectic method. The multi-symplectic formulations are derived including the multi-symplectic form and three local conservation laws of the nonlinear perturbed Schrödinger equation. Employing the implicit midpoint rule, we construct a multi-symplectic scheme, which is equivalent to the Preissmann box scheme, for the nonlinear perturbed Schrödinger equation. …


Normalized Solutions For Sobolev Critical Schrödinger-Bopp-Podolsky Systems, Yuxin Li, Xiaojun Chang, Zhaosheng Feng Sep 2023

Normalized Solutions For Sobolev Critical Schrödinger-Bopp-Podolsky Systems, Yuxin Li, Xiaojun Chang, Zhaosheng Feng

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We study the Sobolev critical Schr¨odinger-Bopp-Podolsky system −∆u + φu = λu + µ|u|p−2u + |u|4u in R3, −∆φ + ∆2φ = 4πu2 in R3, under the mass constraint u2 dx = c R3 for some prescribed c > 0, where 2 < p < 8/3, µ > 0 is a parameter, and λ ∈ R is a Lagrange multiplier. By developing a constraint minimizing approach, we show that the above system admits a local minimizer. Furthermore, we establish the existence of normalized ground state solutions.


Axion-Polaritons In The Magnetic Dual Chiral Density Wave Phase Of Dense Qcd, Efrain J. Ferrer, Vivian De La Incera Sep 2023

Axion-Polaritons In The Magnetic Dual Chiral Density Wave Phase Of Dense Qcd, Efrain J. Ferrer, Vivian De La Incera

Physics and Astronomy Faculty Publications and Presentations

We investigate the propagation of electromagnetic radiation in the magnetic dual chiral density wave (MDCDW) phase of dense quark matter. Considering the theory of low-energy fluctuations in this phase, we show how linearly polarized photons reaching the MDCDW medium couple to the fluctuation field to produce two hybridized modes of propagation that we call in analogy with similar phenomenon in condensed matter physics axion polaritons, one of them being gapless and the other gapped. The gapped mode's gap is proportional to the background magnetic field and inversely proportional to the amplitude of the inhomogeneous condensate. The generation of axion …


Advances And Perspectives Of Using Stable Isotope Probing (Sip)-Based Technologies In Contaminant Biodegradation, Jinha Kim, Myung Hwangbo, Chih-Hsuan Shih, Kung-Hui Chu Sep 2023

Advances And Perspectives Of Using Stable Isotope Probing (Sip)-Based Technologies In Contaminant Biodegradation, Jinha Kim, Myung Hwangbo, Chih-Hsuan Shih, Kung-Hui Chu

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

Highlights

  • Advances of SIP-based techniques/applications are comprehensively reviewed.

  • Varying stable isotopes types/numbers/ positions reinforce biodegradation studies.

  • SIP identifies microbes capable of co-metabolic degradation of contaminants.

  • Single-cell SIP.and qSIP are promising to overcome cross-feeding effects.

Abstract

Stable isotope probing (SIP) is a powerful tool to study microbial community structure and function in both nature and engineered environments. Coupling with advanced genomics and other techniques, SIP studies have generated substantial information to allow researchers to draw a clearer picture of what is occurring in complex microbial ecosystems. This review provides an overview of the advances of SIP-based technologies over time, summarizes the …


Advances And Perspectives Of Using Stable Isotope Probing (Sip)-Based Technologies In Contaminant Biodegradation, Jinha Kim, Myung Hwangbo, Chih-Hsuan Shih, Kung-Hui Chu Sep 2023

Advances And Perspectives Of Using Stable Isotope Probing (Sip)-Based Technologies In Contaminant Biodegradation, Jinha Kim, Myung Hwangbo, Chih-Hsuan Shih, Kung-Hui Chu

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

Stable isotope probing (SIP) is a powerful tool to study microbial community structure and function in both nature and engineered environments. Coupling with advanced genomics and other techniques, SIP studies have generated substantial information to allow researchers to draw a clearer picture of what is occurring in complex microbial ecosystems. This review provides an overview of the advances of SIP-based technologies over time, summarizes the status of SIP applications to contaminant biodegradation, provides critical perspectives on ecological interactions within the community, and important factors (controllable and non-controllable) to be considered in SIP experimental designs and data interpretation. Current trend and …


Chloeia Rozbaczyloi, A New Species Of Polychaete (Archinominae: Amphinomidae) And First Record Of The Family For The Nazca Ridge, Southeastern Pacific Ocean, Juan I. Cañete, María S. Romero, Erin E. Easton, Ariadna Mecho, Javier Sellanes Sep 2023

Chloeia Rozbaczyloi, A New Species Of Polychaete (Archinominae: Amphinomidae) And First Record Of The Family For The Nazca Ridge, Southeastern Pacific Ocean, Juan I. Cañete, María S. Romero, Erin E. Easton, Ariadna Mecho, Javier Sellanes

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

Highlights

  • A new species of amphinomid polychaete, Chloeia rozbaczyloi sp. nov. is described.

  • The new species inhabits poorly explored seamounts of the remote Nazca Ridge off Chile.

  • This finding constitutes the first report of the genus Chloeia for Chilean waters.

  • Genetic data for Chloeia rozbaczyloi sp. nov is provided.

  • The new species is reported for seamounts lying within the recently created Nazca Desventuradas Marine Park.

Abstract

The amphinomid polychaete Chloeia rozbaczyloi sp. nov., collected from seamounts of the Nazca Ridge (NR), northwest of Desventuradas islands, southeastern Pacific Ocean, is described. The new species was observed on only two of seven …


Constrained Quantization For A Uniform Distribution With Respect To A Family Of Constraints, Megha Pandey, Mrinal Kanti Roychowdhury Sep 2023

Constrained Quantization For A Uniform Distribution With Respect To A Family Of Constraints, Megha Pandey, Mrinal Kanti Roychowdhury

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

In this paper, with respect to a family of constraints for a uniform probability distribution we determine the optimal sets of n-points and the nth constrained quantization errors for all positive integers n. We also calculate the constrained quantization dimension and the constrained quantization coefficient. The work in this paper shows that the constrained quantization dimension of an absolutely continuous probability measure depends on the family of constraints and is not always equal to the Euclidean dimension of the underlying space where the support of the probability measure is defined.


Powerful Radio Sources In The Southern Sky. Ii. A Swift X-Ray Perspective, Francesco Massaro, S. V. White, A. Paggi, A. Jimenez-Gallardo, Juan P. Madrid, C. Mazzucchelli, W. R. Forman, A. Capetti, C. C. Cheung Sep 2023

Powerful Radio Sources In The Southern Sky. Ii. A Swift X-Ray Perspective, Francesco Massaro, S. V. White, A. Paggi, A. Jimenez-Gallardo, Juan P. Madrid, C. Mazzucchelli, W. R. Forman, A. Capetti, C. C. Cheung

Physics and Astronomy Faculty Publications and Presentations

We recently constructed the G4Jy-3CRE, a catalog of extragalactic radio sources based on the GLEAM 4-Jy (G4Jy) sample, with the aim of increasing the number of powerful radio galaxies and quasars with similar selection criteria to those of the revised release of the Third Cambridge Catalog (3CR). The G4Jy-3CRE consists of a total of 264 radio sources mainly visible from the Southern Hemisphere. Here, we present an initial X-ray analysis of 89 G4Jy-3CRE radio sources with archival X-ray observations from the Neil Gehrels Swift Observatory. We reduced a total of 624 Swift observations, for about 0.9 Ms of integrated exposure …


Saturating Growth Rate Against Phosphorus Concentration Explained By Macromolecular Allocation, Gabrielle Armin, Jongsun Kim, Keisuke Inomura Aug 2023

Saturating Growth Rate Against Phosphorus Concentration Explained By Macromolecular Allocation, Gabrielle Armin, Jongsun Kim, Keisuke Inomura

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

The saturating relationship between phytoplankton growth rate and environmental nutrient concentration has been widely observed, yet the mechanisms behind the relationship remain elusive. Here, we use a mechanistic model of phytoplankton and show that the saturating relationship between growth rate and phosphorous concentration can be interpreted by intracellular macromolecular allocation. At low nutrient levels, the diffusive nutrient transport linearly increases with the phosphorous concentration, while the internal phosphorous requirement increases with the growth rate, leading to a non-linear increase in the growth rate with phosphorous. This increased phosphorous requirement is due to the increased allocation to biosynthetic and photosynthetic molecules. …


Hellings And Downs Correlation Of An Arbitrary Set Of Pulsars, Bruce Allen, Joseph D. Romano Aug 2023

Hellings And Downs Correlation Of An Arbitrary Set Of Pulsars, Bruce Allen, Joseph D. Romano

Physics and Astronomy Faculty Publications and Presentations

Pulsar timing arrays (PTAs) detect gravitational waves (GWs) via the correlations they induce in the arrival times of pulses from different pulsars. We assume that the GWs are described by a Gaussian ensemble, which models the confusion noise produced by expected PTA sources. The mean correlation h2μu(γ) as a function of the angle γ between the directions to two pulsars was predicted by Hellings and Downs in 1983. The variance σ2tot(γ) in this correlation was recently calculated [B. Allen, Variance of the Hellings-Downs correlation, Phys. Rev. D 107, 043018 (2023)] for a single noise-free pulsar pair at angle γ, …


Hellings And Downs Correlation Of An Arbitrary Set Of Pulsars, Bruce Allen, Joseph D. Romano Aug 2023

Hellings And Downs Correlation Of An Arbitrary Set Of Pulsars, Bruce Allen, Joseph D. Romano

Physics and Astronomy Faculty Publications and Presentations

Pulsar timing arrays (PTAs) detect gravitational waves (GWs) via the correlations they induce in the arrival times of pulses from different pulsars. We assume that the GWs are described by a Gaussian ensemble, which models the confusion noise produced by expected PTA sources. The mean correlation h2μu(γ) as a function of the angle γ between the directions to two pulsars was predicted by Hellings and Downs in 1983. The variance σ2tot(γ) in this correlation was recently calculated [B. Allen, Variance of the Hellings-Downs correlation, Phys. Rev. D 107, 043018 (2023)] for a single noise-free pulsar pair at angle γ, …


Stability Analyses On The Effect Of Vaccination And Contact Tracing In Monkeypox Virus Transmission, Solomon Eshun, Richmond Essieku, James Ladzekpo Aug 2023

Stability Analyses On The Effect Of Vaccination And Contact Tracing In Monkeypox Virus Transmission, Solomon Eshun, Richmond Essieku, James Ladzekpo

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Monkeypox is a significant health concern due to its potential for morbidity and occasional mortality. Vaccination and effective contact tracing play pivotal roles in controlling infectious diseases, including monkeypox. This study aims to contribute to our understanding of monkeypox dynamics by developing a comprehensive mathematical model that incorporates key factors such as vaccination, quarantining, and contact tracing. Through rigorous sensitivity analysis, we explore the impact of varying vaccination coverage and contact tracing on the disease’s dynamics. In particular, we investigate the dynamics of the disease in relation to variable vaccination coverage and contact tracing. Our findings highlight the critical role …


Sulfur Cycling Connects Microbiomes And Biogeochemistry In Deep-Sea Hydrothermal Plumes, Zhichao Zhou, Patricia Q. Tran, Alyssa M. Adams, Kristopher Kieft, John A. Breier, Caroline S. Fortunato, Cody S. Sheik, Julie A. Huber, Meng Li, Gregory J. Dick, Karthik Anantharaman Aug 2023

Sulfur Cycling Connects Microbiomes And Biogeochemistry In Deep-Sea Hydrothermal Plumes, Zhichao Zhou, Patricia Q. Tran, Alyssa M. Adams, Kristopher Kieft, John A. Breier, Caroline S. Fortunato, Cody S. Sheik, Julie A. Huber, Meng Li, Gregory J. Dick, Karthik Anantharaman

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

In globally distributed deep-sea hydrothermal vent plumes, microbiomes are shaped by the redox energy landscapes created by reduced hydrothermal vent fluids mixing with oxidized seawater. Plumes can disperse over thousands of kilometers and their characteristics are determined by geochemical sources from vents, e.g., hydrothermal inputs, nutrients, and trace metals. However, the impacts of plume biogeochemistry on the oceans are poorly constrained due to a lack of integrated understanding of microbiomes, population genetics, and geochemistry. Here, we use microbial genomes to understand links between biogeography, evolution, and metabolic connectivity, and elucidate their impacts on biogeochemical cycling in the deep sea. Using …


Invading The Integrity Of Deep Learning (Dl) Models Using Lsb Perturbation & Pixel Manipulation, Ashraful Tauhid Aug 2023

Invading The Integrity Of Deep Learning (Dl) Models Using Lsb Perturbation & Pixel Manipulation, Ashraful Tauhid

Theses and Dissertations

The use of deep learning (DL) models for solving classification and recognition-related problems are expanding at an exponential rate. However, these models are computationally expensive both in terms of time and resources. This imposes an entry barrier for low-profile businesses and scientific research projects with limited resources. Therefore, many organizations prefer to use fully outsourced trained models, cloud computing services, pre-trained models are available for download and transfer learning. This ubiquitous adoption of DL has unlocked numerous opportunities but has also brought forth potential threats to its prospects. Among the security threats, backdoor attacks and adversarial attacks have emerged as …


Fedbiometric: Image Features Based Biometric Presentation Attack Detection Using Hybrid Cnns-Svm In Federated Learning, S M Sarwar Aug 2023

Fedbiometric: Image Features Based Biometric Presentation Attack Detection Using Hybrid Cnns-Svm In Federated Learning, S M Sarwar

Theses and Dissertations

In the past few years, biometric identification systems have become popular for personal, national, and global security. In addition to other biometric modalities, facial and fingerprint recognition have gained popularity due to their uniqueness, stability, convenience, and cost-effectiveness compared to other biometric modalities. However, the evolution of fake biometrics, such as printed materials, 2D or 3D faces, makeup, and cosmetics, has brought new challenges. As a result of these modifications, several facial and fingerprint Presentation Attack Detection methods have been proposed to distinguish between live and spoof faces or fingerprints. Federated learning can play a significant role in this problem …