Digital Commons Network^™

Embryonic Exposure To The Benzotriazole Ultraviolet Stabilizer 2-(2h-Benzotriazol-2-Yl)-4-Methylphenol Decreases Fertility Of Adult Zebrafish (Danio Rerio), Yamin Raza, Emily Mertens, Lauren Zink, Zhe Lu, Jon A. Doering, Steve Wiseman

Faculty Publications

Benzotriazole ultraviolet stabilizers (BUVSs) are emerging contaminants of concern. They are added to a variety of products, including building materials, personal care products, paints, and plastics, to prevent degradation caused by ultraviolet (UV) light. Despite widespread occurrence in aquatic environments, little is known regarding the effects of BUVSs on aquatic organisms. The aim of the present study was to characterize the effects of exposure to 2-(2H-benzotriazol-2-yl)-4-methylphenol (UV-P) on the reproductive success of zebrafish (Danio rerio) following embryonic exposure. Embryos were exposed, by use of microinjection, to UV-P at < 1.5 (control), 2.77, and 24.25 ng/g egg, and reared until sexual maturity, when reproductive performance was assessed, following which molecular and biochemical endpoints were analyzed. Exposure to UV-P did not have a significant effect on fecundity. However, there was a significant effect on fertilization success. Using UV-P-exposed males and females, fertility was decreased by 8.75% in the low treatment group and by 15.02% in the high treatment group relative to control. In a reproduction assay with UV-P-exposed males and control females, fertility was decreased by 11.47% in the high treatment group relative to the control. Embryonic exposure to UV-P might have perturbed male sex steroid synthesis as indicated by small changes in blood plasma concentrations of 17β-estradiol and 11-ketotestosterone, and small statistically nonsignificant decreases in mRNA abundances of cyp19a1a, cyp11c1, and hsd17b3. In addition, decreased transcript abundances of genes involved in spermatogenesis, such as nanos2 and dazl, were observed. Decreases in later stages of sperm development were observed, suggesting that embryonic exposure to UV-P impaired spematogenesis, resulting in decreased sperm quantity. The present study is the first to demonstrate latent effects of BUVSs, specifically on fish reproduction. Environ Toxicol Chem 2024;43:385–397. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Short-Term Sediment Dispersal On A Large Retreating Coastal River Delta Via 234th And 7be Sediment Geochronology: The Mississippi River Delta Front, Andrew Courtois, Samuel Bentley, Jillian Maloney, Kehui Xu, Jason Chaytor, Ioannis Y. Georgiou, Michael D. Miner, Jeffrey Obelcz, Navid H. Jafari, Melanie Damour

Faculty Publications

Many Mississippi River Delta studies have shown recent declines in fluvial sediment load from the river and associated land loss. In contrast, recent sedimentary processes on the subaqueous delta are less documented. To help address this knowledge gap, multicores were collected offshore from the three main river outlets at water depths of 25–280 m in June 2017 just after the peak river discharge period, with locations selected based on 2017 U.S. Geological Survey seabed mapping. The coring locations included the undisturbed upper foreset, mudflow lobes, gullies, and the undisturbed prodelta. Nine multicores were analyzed for Beryllium-7 activity, and four cores …

Engineering A Non-Hermitian Second-Order Topological Insulator State In Quasicrystals, Chakradhar Rangi, Ka Ming Tam, Juana Moreno

Faculty Publications

Non-Hermitian topological phases have gained immense attention due to their potential to unlock novel features beyond Hermitian bounds. PT-symmetric (parity time-reversal symmetric) non-Hermitian models have been studied extensively over the past decade. In recent years, the topological properties of general non-Hermitian models, regardless of the balance between gains and losses, have also attracted vast attention. Here, we propose a non-Hermitian second-order topological (SOT) insulator that hosts gapless corner states on a two-dimensional quasicrystalline lattice (QL). We first construct a non-Hermitian extension of the Bernevig-Hughes-Zhang model on a QL generated by the Amman-Beenker tiling. This model has real spectra and supports …

Approaching 25 Years Of Progress Towards Fusarium Head Blight Resistance In Southern Soft Red Winter Wheat (Triticum Aestivum L.), Richard E. Boyles, Carolina Ballén-Taborda, Gina Brown-Guedira, Jose Costa, Christina Cowger, Noah Dewitt, Carl A. Griffey, Stephen A. Harrison, Amir Ibrahim, Jerry Johnson, Jeanette Lyerly, David S. Marshall, R. Esten Mason, Mohamed Mergoum, J. Paul Murphy, Nicholas Santantonio, Gautam Saripalli, Russell Sutton, Vijay Tiwari, David Van Sanford, Zachary J. Winn

Faculty Publications

Tremendous progress has been made in variety development and host plant resistance to mitigate the impact of Fusarium head blight (FHB) since the disease manifested in the southeastern United States in the early 2000s. Much of this improvement was made possible through the establishment of and recurring support from the US Wheat & Barley Scab Initiative (USWBSI). Since its inception in 1997, the USWBSI has enabled land-grant institutions to make advances in reducing the annual threat of devastating FHB epidemics. A coordinated field phenotyping effort for annual germplasm screening has become a staple tool for selection in public and private …

Irrigation Of Sand-Based Creeping Bentgrass Putting Greens With Nanobubble-Oxygenated Water, Eric J. Deboer, Michael D. Richardson, John H. Mccalla

Faculty Publications

Cultural and environmental factors can place creeping bentgrass (Agrostis stolonifera) under extreme stress during the summer months. This stress, coupled with the growth adaptation of creeping bentgrass, can result in shallow, poorly rooted stands of turf. To enhance root zone oxygen and rooting of creeping bentgrass, golf courses use methods such as core and solid-tine aerification, and sand topdressing. An additional method of delivering oxygen to the soil could be irrigation with nanobubble-oxygenated water. The properties of nanobubbles (NBs) allow for high gas dissolution rates in water. Irrigating with NB-oxygenated water sources may promote increased rooting of creeping bentgrass putting …

Hamiltonian Formulation And Symplectic Split-Operator Schemes For Time-Dependent Density-Functional-Theory Equations Of Electron Dynamics In Molecules, François Mauger, Cristel Chandre, Mette B. Gaarde, Kenneth Lopata, Kenneth J. Schafer

Faculty Publications

We revisit Kohn–Sham time-dependent density-functional theory (TDDFT) equations and show that they derive from a canonical Hamiltonian formalism. We use this geometric description of the TDDFT dynamics to define families of symplectic split-operator schemes that accurately and efficiently simulate the time propagation for certain classes of DFT functionals. We illustrate these with numerical simulations of the far-from-equilibrium electronic dynamics of a one-dimensional carbon chain. In these examples, we find that an optimized 4th order scheme provides a good compromise between the numerical complexity of each time step and the accuracy of the scheme. We also discuss how the Hamiltonian structure …

Life Cycle Assessment Of Hydrothermal Carbonization: A Review Of Product Valorization Pathways, Andrea Ogunleye, Joseph Flora, Nicole Berge

Faculty Publications

Hydrothermal carbonization (HTC) has the potential to be a sustainable and environmentally beneficial approach for organic waste treatment. It is likely that HTC product use will dictate the viability of large-scale HTC facilities; therefore, understanding the viability and environmental implications associated with HTC product valorization pathways is critical. The overall goal of this review is to gain an understanding of how HTC product valorization is currently being modeled in life cycle assessment studies, and to use such information to assess current research and/or data needs associated with product valorization. To accomplish this, a review of existing HTC literature was conducted …

Sedimentary Processes And Instability On The Mississippi River Delta Front Near The Shipwreck Of The Ss Virginia, Nathan Figueredo, Samuel J. Bentley, Jason D. Chaytor, Kehui Xu, Navid Jafari, Ioannis Y. Georgiou, Melanie Damour, Jeffrey Duxbury, Jeffrey Obelcz, Jillian Maloney

Faculty Publications

Sediment cores were collected from a mudflow lobe (80 m water depth) offshore of the Mississippi River’s Southwest Pass in 2017 to better understand the sedimentology near the lobe entraining the SS Virginia shipwreck (sunk by a German U-boat in 1942) and surrounding Mississippi River delta front. Core analyses included ²¹⁰Pb/¹³⁷Cs geochronology, granulometry, and X-radiography. Sediment accumulation rates (SAR) calculated from excess ²¹⁰Pb activity in multicores are 0.22–0.29 cm/y at seabed depths less than 20 cm and 0.29–0.51 cm/y at depths greater than 20 cm. Accumulation rates for ¹³⁷Cs have been ~0.15 to ~0.37 cm/y …

Simultaneous Detection And Quantification Of Multiple Pathogen Targets In Wastewater, Gouthami Rao, Drew Capone, Kevin Zhu, Abigail Knoble, Yarrow Linden, Ryan Clark, Amanda Lai, Juhee Kim, Ching Hua Huang, Aaron Bivins, Joe Brown

Faculty Publications

Wastewater-based epidemiology has emerged as a critical tool for public health surveillance, building on decades of environmental surveillance work for pathogens such as poliovirus. Work to date has been limited to monitoring a single pathogen or small numbers of pathogens in targeted studies; however, few studies consider simultaneous quantitative analysis of a wide variety of pathogens, which could greatly increase the utility of wastewater surveillance. We developed a novel quantitative multi-pathogen surveillance approach (35 pathogen targets including bacteria, viruses, protozoa, and helminths) using TaqMan Array Cards (TAC) and applied the method on concentrated wastewater samples collected at four wastewater treatment …

Energy And Spectrum Efficient Federated Learning Via High-Precision Over-The-Air Computation, Liang Li, Chenpei Huang, Dian Shi, Hao Wang, Xiangwei Zhou, Minglei Shu, Miao Pan

Faculty Publications

Federated learning (FL) enables mobile devices to collaboratively learn a shared prediction model while keeping data locally. However, there are two major research challenges to practically deploy FL over mobile devices: (i) frequent wireless updates of huge size gradients v.s. limited spectrum resources, and (ii) energy-hungry FL communication and local computing during training v.s. battery-constrained mobile devices. To address those challenges, in this paper, we propose a novel multi-bit over-the-air computation (M-AirComp) approach for spectrum-efficient aggregation of local model updates in FL and further present an energy-efficient FL design for mobile devices. Specifically, a high-precision digital modulation scheme is designed …

The Juan De La Cruz Molino: Folk Architecture At El Güique-Estaca New Mexico, José A. Rivera Ph.D

Faculty Publications

El Güique and Estaca are twin communities just north of the confluence of the Río Grande and the Río Chama. Like other Spanish colonial settlements in the historic Río Arriba, acequia-based agriculture was essential for food production in this high desert region of the northern Río Grande. Along with the construction of acequias, molinos (grist mills) were built to grind wheat into flour as part of the subsistence farming economy of the times. While acequias were communal, molinos most often were constructed and operated as private enterprises by local millers like the case of Juan de la Cruz Borrego and …

A Codified Liabilty Regime To Stimulate Greater Investment In Subpatentable Innovation, Ana Santos Rutschman, Jerome H. Reichman

Faculty Publications

The global intellectual property system rests on a distinction between exclusive property rights and free competition. Exclusive rights vary in strength and intensity, but the opposite of protection is almost always free competition. Distinctions of intensity are drawn in terms of the length of protection given to different subject matters plus variable lists of exceptions and limitations to exclusive rights. But the bottom line is that, when protection is not available under the existing system, free competition prevails, and vice-versa (i.e., where there is exclusivity, free competition is deferred for a specified period of time).

This Article departs from a …

Natural Language Processing Analysis Of Online Reviews For Small Business: Extracting Insight From Small Corpora, Benjamin J. Mccloskey, Phillip M. Lacasse, Bruce A. Cox

Faculty Publications

Receiving and acting on customer input is essential to sustaining and growing any service organization, particularly a small family business whose livelihood depends on strong relationships with its customers. The competitive advantage offered by advanced analytical approaches for supporting decisions is not trivial, and enterprises across virtually all domains of society are investing heavily in this emerging discipline. Natural Language Processing (NLP) is a subset of computer science that employs computational approaches to analyze human language; it is effective at extracting insight from text data but frequently requires large corpora to train its models, in the scale of thousands or …

The Nitrogen Footprint Of Ukraine: Why Personal Consumption Matters, Sergiy Medinets, Allison M. Leach, Tetiana Pavlik, Volodymyr Medinets, James N. Galloway

Faculty Publications

Unintended reactive nitrogen (N) losses from agriculture, energy and transportation pose significant environmental hazards, including eutrophication, acidification, water and air pollution, biodiversity loss, human health risks and climate change. The concept of a nitrogen footprint (NF) emerges as a pivotal metric, reflecting potential N losses in the entire production-consumption chain of goods and services used by an individual within a defined timeframe.In a pioneering assessment of per capita NF in Ukraine, key factors, such as the food production chain, consumption patterns, connection to wastewater treatment (WWT) system and the efficacy of WWT facilities, were identified as critical components. Addressing specific …

Women At Work: Pathways From Gender Stereotypes To Gender Bias And Discrimination, Madeline E. Heilman, Suzette Caleo, Francesca Manzi

Faculty Publications

Despite important advances, gender-based discrimination continues to hin-der women’s career progress. This review examines the role that gender stereotypes play in promoting gender bias and discrimination. After review- ing what is known about the content of gender stereotypes and examining both their descriptive and prescriptive aspects, we discuss two pathways through which stereotypes result in discrepant work outcomes for women and men. First, we consider how the characterization of women as com- munal but not agentic conflicts with the perceived demands of many male gender-typed jobs and fields, thus promoting perceptions of women’s lack of competence in those areas. Second, …

Structural Information On Supramolecular Copper(Ii) Β-Diketonate Complexes From Atomic Force Microscopy And Analytical Ultracentrifugation, Jonathan S. Casey, Ashley R. Walker, Xianglin Zhai, Jayne C. Garno, Paul S. Russo, Andrew W. Maverick

Faculty Publications

Supramolecular Cu(II) complexes were prepared from two trifunctional β-diketone ligands. The ligands (CH3Si(phacH)3 and CH3Si(phprH)3, represented by LH3) contain three aryl-β-diketone moieties joined by an organosilicon group. The complexes have the empirical formula Cu3L2, as expected for combinations of Cu²⁺ and L^3-. Several metal-organic polyhedra (MOPs) [Cu3L2]n are possible (n = 1-10); a dodecahedron (Cu30L20; n = 10; estimated diameter of ca. 5 nm) should be the most stable because its internal bond angles would come closest to ideal values. Atomic force microscopy (AFM), performed on samples deposited from solution onto mica substrates, revealed a distribution of …

Investigating Environmentally Persistent Free Radicals (Epfrs) Emissions Of 3d Printing Process, Farhana Hasan, Phillip M. Potter, Souhail R. Al-Abed, Joanna Matheson, Slawomir M. Lomnicki

Faculty Publications

In recent years, the emission of particles and gaseous pollutants from 3D printing has attracted much attention due to potential health risks. This study investigated the generation of environmentally persistent free radicals (EPFRs, organic free radicals stabilized on or inside particles) in total particulate matter (TPM) released during the 3D printing process. Commercially available 3D printer filaments, made of acrylonitrile–butadiene–styrene (ABS) in two different colors and metal content, ABS-blue (19.66 µg/g Cu) and ABS-black (3.69 µg/g Fe), were used for printing. We hypothesized that the metal content/composition of the filaments contributes not only to the type and number of EPFRs …

Machine-Learning-Assisted Leak Detection Using Distributed Temperature And Acoustic Sensors, Hayden Gemeinhardt, Jyotsna Sharma

Faculty Publications

Small leaks, many of which often go undetected using conventional gauges, remain an urgent problem for an aging pipeline infrastructure. This article proposes a method that allows for an automated and robust leak detection and localization system by fusing distributed acoustic sensor (DAS) and distributed temperature sensor (DTS) data for machine learning. Distributed fiber-optic sensing creates an advantage over conventional gauges by providing real-time continuous measurements along the entire length of the fiber-instrumented pipeline at a high spatiotemporal resolution and sensitivity that can detect small leaks, as well as the leak location. High sensitivity, however, can create noisy data. Thus, …

Scaffold-Based 3d Cell Culture Models In Cancer Research, Waad H. Abuwatfa, William G. Pitt, Ghaleb A. Husseini

Faculty Publications

Three-dimensional (3D) cell cultures have emerged as valuable tools in cancer research, offering significant advantages over traditional two-dimensional (2D) cell culture systems. In 3D cell cultures, cancer cells are grown in an environment that more closely mimics the 3D architecture and complexity of in vivo tumors. This approach has revolutionized cancer research by providing a more accurate representation of the tumor microenvironment (TME) and enabling the study of tumor behavior and response to therapies in a more physiologically relevant context. One of the key benefits of 3D cell culture in cancer research is the ability to recapitulate the complex interactions …

Model Predictive Control Of A Lab-Scale Thermal Energy Storage System In Relap5-3d, Jaron Wallace, Daniel Hill, David Thurston, John Hedengren, Matthew Memmott

Faculty Publications

Increased renewable energy penetration of an electrical grid generally creates more supply fluctuations. Traditional base-load systems, such as nuclear power, can be retrofitted with thermal energy storage (TES) systems to meet supply demand fluctuations. These systems can store energy during low electricity demand times to allow the reactor to operate at constant power while simultaneously fluctuating electricity output. The control of these systems is of vital importance and Model Predictive Control (MPC) is a leading control mechanism for optimized production plans with forecast information. This study combines high fidelity RELAP5-3D models with MPC to control an experimental benchtop system that …

Detection And Classification Of Sporadic E Using Convolutional Neural Networks, J. A. Ellis, Daniel J. Emmons, M. B. Cohen

Faculty Publications

In this work, convolutional neural networks (CNN) are developed to detect and characterize sporadic E (E_s), demonstrating an improvement over current methods. This includes a binary classification model to determine if Es is present, followed by a regression model to estimate the Es ordinary mode critical frequency (foEs), a proxy for the intensity, along with the height at which the Es layer occurs (hEs). Signal-to-noise ratio (SNR) and excess phase profiles from six Global Navigation Satellite System (GNSS) radio occultation (RO) missions during the years 2008–2022 are used as the inputs of the model. Intensity (foEs) and the …

On Lightweight Shape Memory Vitrimer Composites, Siavash Sarrafan, Guoqiang Li

Faculty Publications

Lightweight materials are highly desired in many engineering applications. A popular approach to obtain lightweight polymers is to prepare polymeric syntactic foams by dispersing hollow particles, such as hollow glass microbubbles (HGMs), in a polymer matrix. Integrating shape memory vitrimers (SMVs) in fabricating these syntactic foams enhances their appeal due to the multifunctionality of SMVs. The SMV-based syntactic foams have many potential applications, including actuators, insulators, and sandwich cores. However, there is a knowledge gap in understanding the effect of the HGM volume fraction on different material properties and behaviors. In this study, we prepared an SMV-based syntactic foam to …

Free-Standing 3d Printing Of Epoxy-Vinyl Ether Structures Using Radical-Induced Cationic Frontal Polymerization, Brecklyn R. Groce, Alexandra V. Aucoin, Md Asmat Ullah, Jake Dicesare, Claire Wingfield, Jonathan Sardin, Jackson T. Harris, John C. Nguyen, Patrick Raley, Svetlana S. Stanley, Genevieve Palardy, John A. Pojman

Faculty Publications

The application of frontal polymerization to additive manufacturing has advantages in energy consumption and speed of printing. Additionally, with frontal polymerization, it is possible to print free-standing structures that require no supports. A resin was developed using a mixture of epoxies and vinyl ether with an iodonium salt and peroxide initiating system that frontally polymerizes through radical-induced cationic frontal polymerization. The formulation, which was optimized for reactivity, physical properties, and rheology, allowed the printing of free-standing structures. Increasing ratios of vinyl ether and reactive cycloaliphatic epoxide were found to increase the front velocity. Addition of carbon nanofibers increased the front …

Editorial: Methods And Advances In Marine Geology And Hydrodynamics Environment, Xingsen Guo, Fei Han, Yan Liu, Nan Wu, Cheng Zhang, Ningning Zhang

Faculty Publications

EDITORIAL article Front. Mar. Sci., 12 January 2024Sec. Ocean Observation Volume 11 - 2024 | https://doi.org/10.3389/fmars.2024.1362605

Editorial: Methods And Advances In Marine Geology And Hydrodynamics Environment, Xingsen Guo, Fei Han, Yan Liu, Nan Wu, Cheng Zhang, Ningning Zhang

Faculty Publications

EDITORIAL article Front. Mar. Sci., 12 January 2024Sec. Ocean Observation Volume 11 - 2024 | https://doi.org/10.3389/fmars.2024.1362605

Editorial: Observations And Simulations Of Layering Phenomena In The Middle/Upper Atmosphere And Ionosphere, Bingkun Yu, Xuguang Cai, Daniel J. Emmons Ii, Chong Wang, Jainfei Wu

Faculty Publications

The middle/upper atmosphere and ionosphere are the transition between neutral and ionized components of the Earth’s atmosphere, including stratosphere, mesosphere, thermosphere, ionospheric E region and ionospheric F region (Laštovička et al., 2006; Xu, et al., 2007; Smith, 2012). The atmospheric thermal structure and composition are significantly affected by dynamical processes through coupling. The layering phenomena such as mesospheric metal layers, sporadic E layers, and noctilucent clouds are important tracers to study mechanisms of the vertical coupling from the lower to the upper atmosphere (Dou et al., 2010; Plane, 2012; Xue et al., 2013).

Enhancing Bridge Resilience And Overheight Vehicle Mitigation Through Innovative Sacrificial Cushion Systems, Aly Mousaad Aly, Marc Hoffmann

Faculty Publications

Transportation departments have made significant strides in addressing the challenges posed by the increasing weights of trucks on bridges. While there is a growing awareness of overheight vehicle collisions with bridges, implementing effective countermeasures remains limited. The susceptibility of bridges to damage from such collisions is on the rise, further exacerbated by unpredictable lateral impact forces. This study employs nonlinear impact analysis to assess the response of an unprotected vehicle-girder model, yielding realistic deformation outcomes comparable to observed impacts on the US-61 bridge. Predictions for a truck traveling at 112.65 km/h indicate deformations of 0.229 m, 0.161 m, and 0.271 …

Evaluation Of Colorimetric Rt-Lamp For Screening Of Sars-Cov-2 In Untreated Wastewater, Jesmin Akter, Wendy J.M. Smith, Metasebia Gebrewold, Ilho Kim, Stuart L. Simpson, Aaron Bivins, Warish Ahmed

Faculty Publications

This study compared reverse transcription-loop-mediated isothermal amplification (RT-LAMP) and three reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays targeting the N and E genes of the SARS-CoV-2 genome for detecting RNA in untreated wastewater samples. RT-qPCR assays exhibited consistent amplification down to 2 × 102 GC/reaction, with greater analytical sensitivity at 2 × 101 GC/reaction by US CDC N1 and US CDC N2 assays. In contrast, RT-LAMP exhibited lower sensitivity, detecting SARS-CoV-2 only at or above 2 × 103 GC/reaction. For SARS-CoV-2 seeded wastewater samples, the US CDC N1 assay exhibited greater analytical sensitivity than the US CDC N2, E_Sarbeco, and …

Flexural Behavior Of Pultruded Gfrp–Concrete Composite Beams Strengthened With Gfrp Stiffeners, Muataz I. Ali, Abbas A. Allawi, Ayman El-Zohairy

Faculty Publications

The utilization and incorporation of glass fiber-reinforced plastics (GFRP) in structural applications and architectural constructions are progressively gaining prominence. Therefore, this paper experimentally and numerically investigates the use of GFRP I-beams in conjunction with concrete slabs to form composite beams. The experimental design incorporated 2600 mm long GFRP I-beams which were connected compositely to concrete slabs with a 500 mm width and 80 mm thickness. The concrete slabs are categorized into two groups: concrete slabs cast using normal strength concrete (NSC), and concrete slabs prepared using high-strength concrete (HSC). Various parameters like the type of concrete (normal and high-strength concrete), …

Low Complexity Doa Estimation Of Multiple Coherent Sources Using A Single Direct Data Snapshot, Ahmed A. Hussain, Nizar Tayem, Abdel-Hamid Soliman

Faculty Publications

The direction of arrival (DOA) estimation of multiple radio frequency (RF) coherent signals using conventional algorithms such as Multiple Signal Classification (MUSIC), Estimation of the Signal Parameters via the Rotational Invariance Technique (ESPRIT), and their variants is computationally complex and usually requires a large number of data snapshots for accurate estimation. As the number of antenna elements grows, particularly in massive MIMO systems, the complexity of real-time DOA estimation algorithms significantly rises, placing higher demands on computational power and memory resources. In this paper, we present an efficient approach that operates effectively with just a single snapshot for DOA estimation …