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1. Management of point‐of‐use and point‐of‐entry for regulatory compliance: Survey of state administrators

   https://doi.org/10.1002/aws2.1335  

   Alfredo, Katherine; Wilson, Madelyn; Roberson, Alan (March 2023, AWWA Water Science)

   Abstract The USEPA (United States Environmental Protection Agency) Lead and Copper Rule Revisions allow the use of distributed treatment approaches such as point‐of‐use (POU) and point‐of‐entry (POE) treatment for systems with 10,000 connections or less as a compliance strategy. However, this poses an opportunity for the USEPA to reevaluate system size recommendations for distributed treatment. The current research uses online surveys and semi‐structured interviews (SSIs) to highlight the general sentiment of state regulators managing POU/POE devices and inquiries. Analysis of the 43 survey responses and 13 SSIs revealed that most state regulators described systems of approximately 30–50 connections as the most successful. Resident cooperation, operation and maintenance, monitoring, and the actual implementation of distributed treatment approaches were repeatedly listed as the greatest concerns. As the use of distributed treatment continues to expand, the water sector must devote research efforts to quantitatively determining the drivers of success as well as highlighting clear indicators of potential failure. 

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2. Possibilities of applying the concept of “winter city” in the Russian Arctic (on the example of the city of Nadym).

   https://doi.org/10.25283/2223-4594-2021-2-291-303  

   Fedorov, Roman Y; Sizov, Oleg S; Kuklina, Vera V; Lobanov, Andrei A; Soromotin, Andrei V; Pechkin, Alexander S; Pechkina, Yulia A; Esau, Igor N (April 2021, Arctica)

   null (Ed.)

   On example of the city of Nadym, located in the Yamalo-Nenets Autonomous Area, the authors consider the socio-ecological problems of the development of green, blue and white open urban spaces. The research approach presented in the article is based on the study of a multifaceted complex of urban social and natural systems in their integrated unity, not just as public places, but as biomes — highly integrated urban ecosystems. A posteriori the researchers based on the materials of interviews conducted in 2020 with experts who in different years took part in the study or planned the development of the open urban spaces in Nadym, as well as on the analysis of available publications on this topic and publicly available data. The study found that factors such as the short summer, during which many residents leave the city, as well as the prevalence of freezing temperatures for almost eight months, in fact, transform the green and blue spaces of Nadym into white. This situation indicates the advisability of a more active appeal to the concept of a “winter city” in the development of the city urban environment. The application of the concept principles can be in demand in the process of creating more comfortable living conditions and spatial mobility of the Nadym residents, as well as for developing the recreational opportunities of the city open spaces and integrating them into the natural environment surrounding the city, which in general can be considered as one of the factors for the sustainable development of the city and the formation of post-industrial features in its socio-economic life. 

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3. Sonification of Chemotactic Waves of Bacteria

   https://doi.org/10.21785/icad2023.8263  

   Braun, Rhea; Tfirn, Maxwell; Ford, Roseanne (June 2023, International Community for Auditory Display)

   Chemotaxis is the ability of certain microscopic organisms to sense and swim towards beneficial or away from detrimental chemicals in their surroundings. Identifying this behavior is important for understanding the relationships between species and their environments in the natural world. Predicting migration of an entire population from known characteristics of individual microorganisms is a key contribution, but can be a laborious process and requires watching and waiting for visual evidence of the process on a large population scale. Sonification offers a novel solution to this problem by allowing the observer to tap into our auditory sensory system to process information. In this project, we developed and assessed a proof-of-concept sonification tool as a high throughput, real-time screening tool for chemotaxis in populations of swimming bacteria. The tool operates by reporting the y-axis position of bacteria that appear in the microscope image as microsecond duration pitched notes, giving the user a sense of the average location of the population. In this paper, we present how it has been used as a chemotaxis assay and as a tool to locate traveling waves of bacteria as they pass through the field of view in order to capture data at specific timepoints, which is used to analyze individual swimming patterns of microorganisms within the wave. 

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4. Field Observations of the Evolution of Plunging‐Wave Shapes

   https://doi.org/10.1029/2021GL093664  

   O'Dea, Annika; Brodie, Katherine; Elgar, Steve (August 2021, Geophysical Research Letters)

   Abstract There are few high‐resolution field observations of the water surface during breaking owing to the difficulty of collecting spatially dense measurements in the surf zone, and thus the factors influencing breaking‐wave shape in field conditions remain poorly understood. Here, the shape and evolution of plunging breakers is analyzed quantitatively using three‐dimensional scans of the water surface collected at high spatial and temporal resolution with a multi‐beam terrestrial lidar scanner. The observed internal void shapes in plunging breakers agree well with previously developed theoretical shapes at the onset of breaking, and become more elongated and less steep as breaking progresses. The normalized void area increases as the local bottom slope steepens and as the breaking depth decreases. The void shape becomes more circular as the local bottom slope and the ratio of breaking water depth to wavelength increase, as well as in conditions with opposing winds. 

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5. Computing rank‐revealing factorizations of matrices stored out‐of‐core

   https://doi.org/10.1002/cpe.7726  

   Heavner, N.; Martinsson, P. G.; Quintana‐Ortí, G. (April 2023, Concurrency and Computation: Practice and Experience)

   Summary This paper describes efficient algorithms for computing rank‐revealing factorizations of matrices that are too large to fit in main memory (RAM), and must instead be stored on slow external memory devices such as disks (out‐of‐core or out‐of‐memory). Traditional algorithms for computing rank‐revealing factorizations (such as the column pivoted QR factorization and the singular value decomposition) are very communication intensive as they require many vector‐vector and matrix‐vector operations, which become prohibitively expensive when data is not in RAM. Randomization allows to reformulate new methods so that large contiguous blocks of the matrix are processed in bulk. The paper describes two distinct methods. The first is a blocked version of column pivoted Householder QR, organized as a “left‐looking” method to minimize the number of the expensive write operations. The second method results employs a UTV factorization. It is organized as an algorithm‐by‐blocks to overlap computations and I/O operations. As it incorporates power iterations, it is much better at revealing the numerical rank. Numerical experiments on several computers demonstrate that the new algorithms are almost as fast when processing data stored on slow memory devices as traditional algorithms are for data stored in RAM. 

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