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  1. Abstract

    Over the past 35 years the Buckman wellfield near Santa Fe, New Mexico, experienced production well drawdowns in excess of 180 m, resulting in ground subsidence and surface cracks. Increased reliance on surface water diversions since 2011 has reduced pumping and yielded water level recovery. To characterize the impact of wellfield management decisions on the aquifer system, we reconstruct the surface deformation history through the European Remote Sensing Satellite, Advanced Land Observing Satellite, and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) time series analysis during episodes of drawdown (1993–2000), recovery (2007–2010), and modern management (2015–2018) in discontinuous observations over a 25‐year period. The observed deformation generally reflects changes in hydraulic head. However, at times during the wellfield recovery, the deformation signal is complex, with patterns of uplift and subsidence suggesting a compartmentalized aquifer system. Recent records of locally high geothermal gradients and an overall warming of the system (~0.5°C during the water level recovery) obtained from repeat temperature measurements between 2013 and 2018 constrain a conceptual model of convective heat transfer that requires a vertical permeable zone near an observed fault. To reproduce observed temperature patterns at monitoring wells, high basal heat flow and convective cooling associated with downward flow of water from cool shallow aquifers during the drawdown period is necessary. The fault, however, appears to die out southward or may be locally permeable, as conceptual cross‐sectional hydrologic modeling reproduces the surface deformation without such a structure. Our work demonstrates the importance of incorporating well‐constrained stratigraphy and structure when modeling near‐surface deformation induced by, for instance, groundwater production.

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  2. Summary

    High concentrations of dissolved inorganic carbon in stems of herbaceous and woody C3plants exit leaves in the dark. In the light, C3species use a small portion of xylem‐transported CO2for leaf photosynthesis. However, it is not known if xylem‐transported CO2will exit leaves in the dark or be used for photosynthesis in the light in Kranz‐type C4plants.

    Cut leaves ofAmaranthus hypochondriacuswere placed in one of three solutions of [NaH13CO3] dissolved in KCl water to measure the efflux of xylem‐transported CO2exiting the leaf in the dark or rates of assimilation of xylem‐transported CO2* in the light, in real‐time, using a tunable diode laser absorption spectroscope.

    In the dark, the efflux of xylem‐transported CO2increased with increasing rates of transpiration and [13CO2*]; however, rates of13CeffluxinA. hypochondriacuswere lower compared to C3species. In the light,A. hypochondriacusfixed nearly 75% of the xylem‐transported CO2supplied to the leaf.

    Kranz anatomy and biochemistry likely influence the efflux of xylem‐transported CO2out of cut leaves ofA. hypochondriacusin the dark, as well as the use of xylem‐transported CO2* for photosynthesis in the light. Thus increasing the carbon use efficiency of Kranz‐type C4species over C3species.

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  3. Abstract

    The rapid A‐Ciresponse (RACiR) technique alleviates limitations of measuring photosynthetic capacity by reducing the time needed to determine the maximum carboxylation rate (Vcmax) and electron transport rate (Jmax) in leaves. Photosynthetic capacity and its relationships with leaf development are important for understanding ecological and agricultural productivity; however, our current understanding is incomplete. Here, we show that RACiR can be used in previous generation gas exchange systems (i.e., the LI‐6400) and apply this method to rapidly investigate developmental gradients of photosynthetic capacity in poplar. We compared RACiR‐determined Vcmaxand Jmaxas well as respiration and stomatal conductance (gs) across four stages of leaf expansion inPopulus deltoidesand the poplar hybrid 717‐1B4 (Populus tremula × Populus alba). These physiological data were paired with leaf traits including nitrogen concentration, chlorophyll concentrations, and specific leaf area. Several traits displayed developmental trends that differed between the poplar species, demonstrating the utility of RACiR approaches to rapidly generate accurate measures of photosynthetic capacity. By using both new and old machines, we have shown how more investigators will be able to incorporate measurements of important photosynthetic traits in future studies and further our understanding of relationships between development and leaf‐level physiology.

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  4. Summary

    Traditionally, leaves were thought to be supplied withCO2for photosynthesis by the atmosphere and respiration. Recent studies, however, have shown that the xylem also transports a significant amount of inorganic carbon into leaves through the bulk flow of water. However, little is known about the dynamics and proportion of xylem‐transportedCO2that is assimilated, vs simply lost to transpiration.

    Cut leaves ofPopulus deltoidesandBrassica napuswere placed in eitherKCl or one of three [NaH13CO3] solutions dissolved in water to simultaneously measure the assimilation and the efflux of xylem‐transportedCO2exiting the leaf across light andCO2response curves in real‐time using a tunable diode laser absorption spectroscope.

    The rates of assimilation and efflux of xylem‐transportedCO2increased with increasing xylem [13CO2*] and transpiration. Under saturating irradiance, rates of assimilation using xylem‐transportedCO2accounted forc.2.5% of the total assimilation in both species in the highest [13CO2*].

    The majority of xylem‐transportedCO2is assimilated, and efflux is small compared to respiration. Assimilation of xylem‐transportedCO2comprises a small portion of total photosynthesis, but may be more important whenCO2is limiting.

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  5. The title three-dimensional metal–organic framework (MOF) compound, {(NH 4 ) 2 [Zn 2 (C 9 H 3 O 6 ) 2 ]·2C 5 H 9 NO} n , features an anionic framework constructed from Zn 2+ cations and benzene-1,3,5-tricarboxylate (BTC) organic anions. Charge balance is achieved by outer sphere ammonium cations formed by degradation of di- n -butylamine in the solvothermal synthesis of the compound. Binuclear {Zn 2 (COO) 2 } entities act as the framework's secondary building units. Each Zn II atom has a tetrahedral coordination environment with an O 4 set of donor atoms. The three-dimensional framework adopts a rutile-type topology and channels are filled in an alternating fashion with ordered and disordered 1-methylpyrrolidin-2-one solvent molecules and ammonium cations. The latter are held in the channels via four N—H...O hydrogen bonds, including three with the benzene-1,3,5-tricarboxylate ligands of the anionic framework and one with a 1-methylpyrrolidin-2-one solvent molecule. 
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  6. In the title compound, C 12 H 13 NO 2 , the five-membered ring has an envelope conformation; the disubstituted C atom lies out of the mean plane through the four other ring atoms (r.m.s. deviation = 0.0038 Å) by 0.1877 (18) Å. The plane of the phenyl substituent is practically perpendicular to that of the planar part of the five-membered ring, with a dihedral angle of 87.01 (5)°. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming inversion dimers. The dimers are linked by further C—H...O hydrogen bonds, as well as carbonyl–carbonyl attractive interactions [O...C = 3.2879 (19) Å], forming a three-dimensional framework structure. 
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  7. In an attempt to grow 8-hydroxyquinoline–acetaminophen co-crystals from equimolar amounts of conformers in a chloroform–ethanol solvent mixture at room temperature, the title compound, C 9 H 7 NO, was obtained. The molecule is planar, with the hydroxy H atom forming an intramolecular O—H...N hydrogen bond. In the crystal, molecules form centrosymmetric dimers via two O—H...N hydrogen bonds. Thus, the hydroxy H atoms are involved in bifurcated O—H...N hydrogen bonds, leading to the formation of a central planar four-membered N 2 H 2 ring. The dimers are bound by intermolecular π–π stacking [the shortest C...C distance is 3.2997 (17) Å] and C—H...π interactions into a three-dimensional framework. The crystal grown represents a new monoclinic polymorph in the space group P 2 1 / n . The molecular structure of the present monoclinic polymorph is very similar to that of the orthorhombic polymorph (space group Fdd 2) studied previously [Roychowdhury et al. (1978). Acta Cryst. B 34 , 1047–1048; Banerjee & Saha (1986). Acta Cryst. C 42 , 1408–1411]. The structures of the two polymorphs are distinguished by the different geometries of the hydrogen-bonded dimers, which in the crystal of the orthorhombic polymorph possess twofold axis symmetry, with the central N 2 H 2 ring adopting a butterfly conformation. 
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  8. Surface depletion field would introduce the depletion region near surface and thus could significantly alter the optical, electronic and optoelectronic properties of the materials, especially low-dimensional materials. Two-dimensional (2D) organic—inorganic hybrid perovskites with van der Waals bonds in the out-of-plane direction are expected to have less influence from the surface depletion field; nevertheless, studies on this remain elusive. Here we report on how the surface depletion field affects the structural phase transition, quantum confinement and Stark effect in 2D (BA)2PbI4 perovskite microplates by the thickness-, temperature- and power-dependent photoluminescence (PL) spectroscopy. Power dependent PL studies suggest that high-temperature phase (HTP) and low-temperature phase (LTP) can coexist in a wider temperature range depending on the thickness of the 2D perovskite microplates. With the decrease of the microplate thickness, the structural phase transition temperature first gradually decreases and then increases below 25 nm, in striking contrast to the conventional size dependent structural phase transition. Based on the thickness evolution of the emission peaks for both high-temperature phase and low-temperature phase, the anomalous size dependent phase transition could probably be ascribed to the surface depletion field and the surface energy difference between polymorphs. This explanation was further supported by the temperature dependent PL studies of the suspended microplates and encapsulated microplates with graphene and boron nitride flakes. Along with the thickness dependent phase transition, the emission energies of free excitons for both HTP and LTP with thickness can be ascribed to the surface depletion induced confinement and Stark effect. 
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