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   Van Etten, James L.; Agarkova, Irina V.; Dunigan, David D. (January 2020, Viruses)

   Chloroviruses are large dsDNA, plaque-forming viruses that infect certain chlorella-like green algae; the algae are normally mutualistic endosymbionts of protists and metazoans and are often referred to as zoochlorellae. The viruses are ubiquitous in inland aqueous environments throughout the world and occasionally single types reach titers of thousands of plaque-forming units per ml of native water. The viruses are icosahedral in shape with a spike structure located at one of the vertices. They contain an internal membrane that is required for infectivity. The viral genomes are 290 to 370 kb in size, which encode up to 16 tRNAs and 330 to ~415 proteins, including many not previously seen in viruses. Examples include genes encoding DNA restriction and modification enzymes, hyaluronan and chitin biosynthetic enzymes, polyamine biosynthetic enzymes, ion channel and transport proteins, and enzymes involved in the glycan synthesis of the virus major capsid glycoproteins. The proteins encoded by many of these viruses are often the smallest or among the smallest proteins of their class. Consequently, some of the viral proteins are the subject of intensive biochemical and structural investigation. 

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2. Construction of Chiral, Helical Nanoparticle Superstructures: Progress and Prospects

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   Mokashi‐Punekar, Soumitra; Zhou, Yicheng; Brooks, Sydney_C; Rosi, Nathaniel_L (December 2019, Advanced Materials)

   Abstract Chiral nanoparticle (NP) superstructures, in which discrete NPs are assembled into chiral architectures, represent an exciting and growing class of nanomaterials. Their enantiospecific properties make them promising candidates for a variety of potential applications. Helical NP superstructures are a rapidly expanding subclass of chiral nanomaterials in which NPs are arranged in three dimensions about a screw axis. Their intrinsic asymmetry gives rise to a variety of interesting properties, including plasmonic chiroptical activity in the visible spectrum, and they hold immense promise as chiroptical sensors and as components of optical metamaterials. Herein, a concise history of the foundational conceptual advances that helped define the field of chiral nanomaterials is provided, and some of the major achievements in the development of helical nanomaterials are highlighted. Next, the key methodologies employed to construct these materials are discussed, and specific merits that are offered by each assembly methodology are identified, as well as their potential disadvantages. Finally, some specific examples of the emerging applications of these materials are discussed and some areas of future development and research focus are proposed. 

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3. Direct serendipity finite elements on cuboidal hexahedra

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   Arbogast, Todd; Wang, Chuning (January 2025, Computer Methods in Applied Mechanics and Engineering)

   We construct direct serendipity finite elements on general cuboidal hexahedra, which are 𝐻1-conforming and optimally approximate to any order. The new finite elements are direct in that the shape functions are directly defined on the physical element. Moreover, they are serendipity by possessing a minimal number of degrees of freedom satisfying the conformity requirement. Their shape function spaces consist of polynomials plus (generally nonpolynomial) supplemental functions, where the polynomials are included for the approximation property and supplements are added to achieve 𝐻1 -conformity. The finite elements are fully constructive. The shape function spaces of higher order 𝑟 ≥ 3 are developed first, and then the lower order spaces are constructed as subspaces of the third order space. Under a shape regularity assumption, and a mild restriction on the choice of supplemental functions, we develop the convergence properties of the new direct serendipity finite elements. Numerical results with different choices of supplements are compared on two mesh sequences, one regularly distorted and the other one randomly distorted. They all possess a convergence rate that aligns with the theory, while a slight difference lies in their performance. 

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4. Direct serendipity finite elements on cuboidal hexahedra

   Arbogast, Todd; Wang, Chuning (October 2024, Computer methods in applied mechanics and engineering)

   We construct direct serendipity finite elements on general cuboidal hexahedra, which are H1-conforming and optimally approximate to any order. The new finite elements are direct in that the shape functions are directly defined on the physical element. Moreover, they are serendipity by possessing a minimal number of degrees of freedom satisfying the conformity requirement. Their shape function spaces consist of polynomials plus (generally nonpolynomial) supplemental functions, where the polynomials are included for the approximation property and supplements are added to achieve H1-conformity. The finite elements are fully constructive. The shape function spaces of higher order 𝑟 ≥ 3 are developed first, and then the lower order spaces are constructed as subspaces of the third order space. Under a shape regularity assumption, and a mild restriction on the choice of supplemental functions, we develop the convergence properties of the new direct serendipity finite elements. Numerical results with different choices of supplements are compared on two mesh sequences, one regularly distorted and the other one randomly distorted. They all possess a convergence rate that aligns with the theory, while a slight difference lies in their performance. 

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5. Identifying the Dominant Drivers of Hydrological Change in the Contiguous United States

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   Li, Zhiying; Quiring, Steven M. (May 2021, Water Resources Research)

   Abstract Understanding the dominant drivers of hydrological change is essential for water resources management. Watersheds in the United States are experiencing different types of changes (e.g., wet gets wetter and dry gets drier); however, few studies have analyzed what drivers are responsible for these changes, and how the dominant drivers vary over time and as a function of the climate/water regime and land cover. This study uses a time‐varying Budyko framework to quantify the relative importance of precipitation, potential evapotranspiration, and other factors (e.g., climate seasonality, agricultural drainage, and urbanization) in 889 watersheds in the contiguous United States from 1950 to 2009. Results show that watersheds that are getting wetter are primarily due to increases in precipitation. However, watersheds in dry climates that are getting drier are primarily due to other factors, while watersheds in wet climates that are getting drier are primarily due to precipitation. The drivers causing statistically significant streamflow trends vary depending on dominant land‐use types. Temporally, the increasing effects of other factors are more pronounced after the 1980s in the Midwest. The dominant drivers of streamflow in the United States are time‐varying instead of constant. This is consistent with non‐stationary patterns of streamflow. The time‐varying drivers provide information on the processes that are increasingly important and require the most attention in water resources management. 

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