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1. Role of external inputs of nutrients to aquatic ecosystems in determining prevalence of nitrogen vs. phosphorus limitation of net primary productivity

   https://doi.org/10.1007/s10533-021-00765-z  

   Howarth, R. W.; Chan, F.; Swaney, D. P.; Marino, R. M.; Hayn, M. (February 2021, Biogeochemistry)

   null (Ed.)

   Abstract Whether net primary productivity in an aquatic ecosystem is limited by nitrogen (N), limited by phosphorus (P), or co-limited by N & P is determined by the relative supply of N and P to phytoplankton compared to their elemental requirements for primary production, often characterized by the “Redfield” ratio. The supply of these essential nutrients is affected by both external inputs and biogeochemical processes within the ecosystem. In this paper, we examine external sources of nutrients to aquatic systems and how the balance of N to P inputs influences nutrient limitation. For ocean subtropical gyres, a relatively balanced input of N and P relative to the Redfield ratio from deep ocean sources often leads to near co-limitation by N and P. For lakes, the external nutrient inputs come largely from watershed sources, and we demonstrate that on average the N:P ratio for these inputs across the United States is well above that needed by phytoplankton, which may contribute to P limitation in those lake that experience this average nutrient loading. Watershed inputs are also important for estuaries and coastal marine ecosystems, but ocean sources of nutrients are also significant contributors to overall nutrient loads. The ocean-nutrient sources of N and P are very often at or below the Redfield ratio of 16:1 molar, and can be substantially so, particularly in areas where the continental shelf is wide. This large input of coastal ocean nutrients with a low N:P ratio is one factor that may make N limitation more likely in many coastal marine ecosystems than in lakes. 

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2. Catalogue of type specimens of lice (Insecta: Psocodea: Phthiraptera) held in the Field Museum of Natural History louse collection

   https://doi.org/10.1635/053.168.0105  

   Kuabara, Kamila M.; Valim, Michel P.; Weckstein, Jason D. (January 2023, Proceedings of the Academy of Natural Sciences of Philadelphia)

   This paper provides a catalogue of the type specimens of lice (Insecta: Psocodea: Phthiraptera) held in the collection of the Field Museum of Natural History (FMNH), Chicago, Illinois, USA. There are 178 nominal species, four of which are represented by holotype only; 14 by holotype, allotype and paratypes; 29 by holotype and paratypes; 127 by paratypes only; three by neoparatypes, and one by paralectotype. The main goal of this type catalog is to make the louse type specimens and their metadata more readily available to biodiversity researchers. 

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3. Relation of Gravity, Winds, and the Moment of Inertia of Jupiter and Saturn

   https://doi.org/10.3847/psj/acd2cd  

   Militzer, Burkhard; Hubbard, William B. (May 2023, The Planetary Science Journal)

   Abstract We study the relationship of zonal gravity coefficients, J 2 n , zonal winds, and axial moment of inertia (MoI) by constructing models for the interiors of giant planets. We employ the nonperturbative concentric Maclaurin spheroid method to construct both physical (realistic equation of state and barotropes) and abstract (small number of constant-density spheroids) interior models. We find that accurate gravity measurements of Jupiter’s and Saturn’s J 2 , J 4 , and J 6 by the Juno and Cassini spacecraft do not uniquely determine the MoI of either planet but do constrain it to better than 1%. Zonal winds (or differential rotation (DR)) then emerge as the leading source of uncertainty. For Saturn they are predicted to decrease the MoI by 0.4% because they reach a depth of ∼9000 km, while on Jupiter they appear to reach only ∼3000 km. We thus predict DR to affect Jupiter’s MoI by only 0.01%, too small by one order of magnitude to be detectable by the Juno spacecraft. We find that winds primarily affect the MoI indirectly via the gravity harmonic J 6 , while direct contributions are much smaller because the effects of pro- and retrograde winds cancel. DR contributes +6% and −0.8% to Saturn’s and Jupiter’s J 6 value, respectively. This changes the J 6 contribution that comes from the uniformly rotating bulk of the planet that correlates most strongly with the predicted MoI. With our physical models, we predict Jupiter’s MoI to be 0.26393 ± 0.00001. For Saturn, we predict 0.2181 ± 0.0002, assuming a rotation period of 10:33:34 hr that matches the observed polar radius. 

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4. Orthogonal deposition of Au on different facets of Ag cuboctahedra for the fabrication of nanoboxes with complementary surfaces

   https://doi.org/10.1039/c9nr08420g  

   Ahn, Jaewan; Kim, Junki; Qin, Dong (January 2020, Nanoscale)

   We report the fabrication of Ag–Au cuboctahedral nanoboxes enclosed by {100} and {111} facets, respectively, through the orthogonal deposition of Au on two different facets of Ag cuboctahedra. Specifically, we titrate aqueous HAuCl 4 into an aqueous mixture containing Ag cuboctahedra, ascorbic acid, and NaOH (under basic conditions), in the presence of poly(vinylpyrrolidone) (PVP) and cetyltrimethylammonium chloride (CTAC), respectively. In the case of PVP, the oxidation of Ag was initiated from the {111} facets of the cuboctahedra through the galvanic replacement reaction between Au( iii ) and Ag, accompanied by the deposition of Au onto the {100} facets. Because the dissolved Ag( i ) ions could react with NaOH to form Ag 2 O on the {111} facets and thus terminate the galvanic reaction, the Au( iii ) ions would be further reduced by the ascorbate monoanion (HAsc − ) to generate Au atoms for their continuing deposition on the {100} facets, converting Ag cuboctahedra to Ag@Au {100} cuboctahedra. Upon the etching of Ag from the core, we obtained Ag–Au cuboctahedral nanoboxes enclosed by {100} facets. In contrast, when CTAC was present, the oxidation of Ag through a galvanic reaction could continuously proceed on {100} facets as the dissolved Ag( i ) ions would react with the excessive amount of Cl − ions derived from CTAC to produce soluble AgCl 2 − ions rather than insoluble Ag 2 O. As a result, the dissolved Ag( i ) and Au( iii ) ions would be co-reduced by HAsc − for the generation of Ag and Au atoms, followed by their co-deposition onto {111} facets for the generation of Ag@Au {111} concave cuboctahedra. After the removal of Ag from the core by etching, we obtained Ag–Au {111} cuboctahedral nanoboxes enclosed by {111} facets. Both samples of cuboctahedral nanoboxes exhibited strong optical absorption in the infrared region. Interestingly, the cuboctahedral nanoboxes enclosed by {111} facets showed significantly enhanced catalytic activity toward the reduction of 4-nitrophenol by NaBH 4 relative to their counterparts encased by {100} facets. 

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5. Maximizers of nonlocal interactions of Wasserstein Type

   https://doi.org/10.1051/cocv/2024068  

   Burchard, Almut; Carazzato, Davide; Topaloglu, Ihsan (October 2024, ESAIM: Control, Optimisation and Calculus of Variations)

   We characterize the maximizers of a functional that involves the minimization of the Wasserstein distance between sets of equal volume. We prove that balls are the only maximizers by combining a symmetrization-by-reflection technique with the uniqueness of optimal transport plans. Further, in one dimension, we provide a sharp quantitative refinement of this maximality result. 

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