cssi/SciSciGPT-SciSciNet huggingface dataset:
Chapter 7 – Numerical Solution of Finite Element Equations

Numerical methods of solving different types of finite element equations are presented. For solving equilibrium equations, the Gaussian elimination method and Choleski method (for symmetric matrices) are presented. For solving the matrix eigenvalue problem, first the methods of converting a general eigenvalue problem into a standard eigenvalue problem are presented. Then some of the popular methods used for solving the eigenvalue problem, including the Jacobi method, power method, and Rayleigh–Ritz subspace iteration method, are presented. For solving the equations of propagation problems, first the equations are converted into a set of simultaneous first-order differential equations with appropriate boundary conditions. Then methods for solving the first-order differential equations, including the fourth-order Runge–Kutta numerical method and the direct integration methods (finite difference method and Newmark method) as well as the mode superposition method are presented. The computational details of most of the methods are illustrated with examples. Finally, the feasibility of using parallel processing in finite element analysis is indicated.
An integrated transmission and distribution test system for evaluation of transactive energy designs

Abstract This study presents an open-source software platform specifically tailored to permit careful dynamic performance evaluation of transactive energy designs for end-to-end electric power systems. The platform models a centrally-managed wholesale power market operating over a transmission grid linked to one or more distribution systems, where each distribution system consists of a collection of grid-edge resources operating over a distribution grid. Test case findings are presented to illustrate the capabilities of the platform. The test cases implement a transmission system linked to a distribution system populated by households that have smart price-responsive appliances as well as conventional loads. Transactions at the distribution level are conducted in accordance with a well-known bid-based transactive energy design known as the PowerMatcher.
Medial orbitofrontal cortex, dorsolateral prefrontal cortex, and hippocampus differentially represent the event saliency

Two primary functions attributed to the hippocampus and prefrontal cortex (PFC) network are retaining the temporal and spatial associations of events and detecting deviant events. It is unclear, however, how these two functions converge into one mechanism. Here, we tested whether increased activity with perceiving salient events is a deviant detection signal or contains information about the event associations by reflecting the magnitude of deviance (i.e., event saliency). We also tested how the deviant detection signal is affected by the degree of anticipation. We studied regional neural activity when people watched a movie that had varying saliency of a novel or an anticipated flow of salient events. Using intracranial electroencephalography from 10 patients, we observed that high-frequency activity (50-150 Hz) in the hippocampus, dorsolateral PFC, and medial OFC tracked event saliency. We also observed that medial OFC activity was stronger when the salient events were anticipated than when they were novel. These results suggest that dorsolateral PFC and medial OFC, as well as the hippocampus, signify the saliency magnitude of events, reflecting the hierarchical structure of event associations.
Pricing Bermudan Variance Swaptions Using Multinomial Trees

In a recent study, Zhao et al. (2017) presented a tree methodology to evaluate the expected generalized realized variance in a general stochastic volatility model; it provided an efficient way of calculating the fair value of the strike for variance swaps. In this article, the authors expand the methodology to price nonlinear derivatives written on realized variance. They introduce a new option contract, a Bermudan variance swaption, defined as an option on variance swap with early exercise dates. Within the same framework they also show how to value forward-start variance swaps, VIX futures, and VIX options. Numerical tests show that the methodology is efficient and accurate.
Statistical distributions of consonant variants in infant-directed speech: evidence that /t/ may be exceptional.

Abstract Statistical distributions of phonetic variants in spoken language influence speech perception for both language learners and mature users. We theorized that patterns of phonetic variant processing of consonants demonstrated by adults might stem in part from patterns of early exposure to statistics of phonetic variants in infant-directed (ID) speech. In particular, we hypothesized that ID speech might involve greater proportions of canonical /t/ pronunciations compared to adult-directed (AD) speech in at least some phonological contexts. This possibility was tested using a corpus of spontaneous speech of mothers speaking to other adults, or to their typically-developing infant. Tokens of word-final alveolar stops – including /t/, /d/, and the nasal stop /n/ – were examined in assimilable contexts (i.e., those followed by a word-initial labial and/or velar); these were classified as canonical, assimilated, deleted, or glottalized. Results confirmed that there were significantly more canonical pronunciations in assimilable contexts in ID compared with AD speech, an effect which was driven by the phoneme /t/. These findings suggest that at least in phonological contexts involving possible assimilation, children are exposed to more canonical /t/ variant pronunciations than adults are. This raises the possibility that perceptual processing of canonical /t/ may be partly attributable to exposure to canonical /t/ variants in ID speech. Results support the need for further research into how statistics of variant pronunciations in early language input may shape speech processing across the lifespan.
Spontaneous formation of PMB esters using 4-methoxybenzyl-2,2,2-trichloroacetimidate

Abstract Carboxylic acids are converted to the corresponding 4-methoxybenzyl (PMB) esters with 4-methoxybenzyl-2,2,2-trichloroacetimidate in the absence of an acid catalyst. This operationally simple procedure is a highly effective method for the formation of PMB esters. The reaction is promoted by the carboxylic acids themselves in excellent yields (72–99%). Sterically hindered carboxylic acids, which provide lower yields with other imidates, are esterified in higher yield with the more reactive PMB imidate. No racemization is observed in the case of carboxylic acids bearing an α-stereocenter, and no isomerization is observed with Z-α,β-unsaturated acids. This method may therefore find use in the esterification of complex or sensitive substrates where more common techniques lead to decomposition.
Rapid stereoselective reduction of thermally labile 2-aminonitroalkanes.

Abstract Samarium diiodide may be employed in the stereoselective reduction of thermally unstable 2-aminonitroalkanes to give a range of useful 1,2-diamines.
Inferring the direction of rhythmic neural transmission via inter-regional phase-amplitude coupling (ir-PAC).

Phase-amplitude coupling (PAC) estimates the statistical dependence between the phase of a low-frequency component and the amplitude of a high-frequency component of local field potentials (LFP). To date PAC has been mainly applied to one signal. In this work, we introduce a new application of PAC to two LFPs and suggest that it can be used to infer the direction and strength of rhythmic neural transmission between distinct brain networks. This hypothesis is based on the accumulating evidence that transmembrane currents related to action potentials contribute a broad-band component to LFP in the high-gamma band, and PAC calculated between the amplitude of high-gamma (>60 Hz) in one LFP and the phase of a low-frequency oscillation (e.g., theta) in another would therefore relate the output (spiking) of one area to the input (somatic/dendritic postsynaptic potentials) of the other. We tested the hypothesis on theta-band long range communications between hippocampus and prefrontal cortex (PFC) and theta-band short range communications between dentate gyrus (DG) and the Ammon’s horn (CA1) within the hippocampus. The ground truth was provided by the known anatomical connections predicting hippocampus → PFC and DG → CA1, i.e., theta transmission is unidirectional in both cases: from hippocampus to PFC and from DG to CA1 along the tri-synaptic pathway within hippocampus. We found that (1) hippocampal high-gamma amplitude was significantly coupled to PFC theta phase, but not vice versa; (2) similarly, DG high-gamma amplitude was significantly coupled to CA1 theta phase, but not vice versa, and (3) the DG high-gamma-CA1 theta PAC was significantly correlated with DG → CA1 Granger causality, a well-established analytical measure of directional neural transmission. These results support the hypothesis that inter-regional PAC (ir-PAC) can be used to relate the output of a rhythmic “driver” network (i.e., high gamma) to the input of a rhythmic “receiver” network (i.e., theta) and thereby establish the direction and strength of rhythmic neural transmission.
Absence of Genome Reduction In Diverse, Facultative Endohyphal Bacteria

Fungi interact closely with bacteria, both on the surfaces of the hyphae and within their living tissues (i.e. endohyphal bacteria, EHB). These EHB can be obligate or facultative symbionts and can mediate diverse phenotypic traits in their hosts. Although EHB have been observed in many lineages of fungi, it remains unclear how widespread and general these associations are, and whether there are unifying ecological and genomic features can be found across EHB strains as a whole. We cultured 11 bacterial strains after they emerged from the hyphae of diverse Ascomycota that were isolated as foliar endophytes of cupressaceous trees, and generated nearly complete genome sequences for all. Unlike the genomes of largely obligate EHB, the genomes of these facultative EHB resembled those of closely related strains isolated from environmental sources. Although all analysed genomes encoded structures that could be used to interact with eukaryotic hosts, pathways previously implicated in maintenance and establishment of EHB symbiosis were not universally present across all strains. Independent isolation of two nearly identical pairs of strains from different classes of fungi, coupled with recent experimental evidence, suggests horizontal transfer of EHB across endophytic hosts. Given the potential for EHB to influence fungal phenotypes, these genomes could shed light on the mechanisms of plant growth promotion or stress mitigation by fungal endophytes during the symbiotic phase, as well as degradation of plant material during the saprotrophic phase. As such, these findings contribute to the illumination of a new dimension of functional biodiversity in fungi.
Photoreaction of nitrobenzenes with hydrobromic acid

Abstract Nitrobenzene and three of its derivatives (3-CO 2 H, 3-OH, and 4-OH) react efficiently when irradiated ( λ >340 nm) in concentrated hydrobromic acid typically to give high yields of 2,4,6-tribromoanilines. The quantum yield ( Φ = 0.16 for nitrobenzene) is not changed appreciably by the electron withdrawing carboxy substituent, but is lowered by the electron donating hydroxy substituent. The reactivity suggests that electron transfer from bromide ion to the n,π* triplet is the primary process.
Total Syntheses of Epothilones A and B

Convergent, stereocontrolled total syntheses of the microtubule-stabilizing macrolides epothilones A (2) and B (3) have been achieved. Four distinct ring-forming strategies were pursued (see Scheme...
Synthesis and biophysical properties of constrained D-altritol nucleic acids (cANA).

The first synthesis of constrained altritol nucleic acids (cANA) containing antisense oligonucleotides (ASOs) was carried out to ascertain how conformationally restricting the d-altritol backbone-containing ASO (Me-ANA) would affect their ability to form duplexes with RNA. It was found that the thermal stability was reduced (cANA/RNA −1.1 °C/modification) compared to DNA/RNA, suggesting the constrained system results in a small destabilizing perturbation in the duplex structure.
Object-finding skill created by repeated reward experience

For most animals, survival depends on rapid detection of rewarding objects, but search for an object surrounded by many others is known to be difficult and time consuming. However, there is neuronal evidence for robust and rapid differentiation of objects based on their reward history in primates (Hikosaka, Kim, Yasuda, & Yamamoto, 2014). We hypothesized that such robust coding should support efficient search for high-value objects, similar to a pop-out mechanism. To test this hypothesis, we let subjects (n = 4, macaque monkeys) view a large number of complex objects with consistently biased rewards with variable training durations (1, 5, or 30 + days). Following training, subjects searched for a high-value object (Good) among a variable number of low-value objects (Bad). Consistent with our hypothesis, we found that Good objects were accurately and quickly targeted, often by a single and direct saccade with a very short latency (<200 ms). The dependence of search times on display size reduced significantly with longer reward training, giving rise to a more efficient search (40 ms/item to 16 ms/item). This object-finding skill showed a large capacity for value-biased objects and was maintained in the long-term memory with no interference from reward learning with other objects. Such object-finding skill, and in particular its large capacity and long term retention, would be crucial for maximizing rewards and biological fitness throughout life where many objects are experienced continuously and/or intermittently.
Experimental Coordination Environment of Uranyl(VI) in Aqueous Solution

The coordination environment of a molecular UO 2 2+ ion in aqueous solution is determined with X-ray scattering and interpreted taking into account the electron redistribution around the uranyl ion. The data indicate that uranyl coordinated to five water molecules is the dominating species, although a small percentage of the uranyl ions are coordinated to four waters. We argue that our result, taken together with calculated relative stabilities of 4- and 5-coordinated UO 2 2+, are consistent with a dynamic equilibrium that favors five coordinating H 2 O. The data further indicate that electron transfer from the uranium(VI) to the uranyl-oxygen is incomplete and that the effective charge of the uranium is less than indicated by its formal valence. In addition, a partial electron transfer from the hydrating waters to the uranium takes place, further lowering the effective charge of the uranium atom. The results described herein are in agreement with recent density functional calculations for an actinyl-water cluster embedded in a dielectric continuum.
On the Continuity of Rotation Representations in Neural Networks

In neural networks, it is often desirable to work with various representations of the same space. For example, 3D rotations can be represented with quaternions or Euler angles. In this paper, we advance a definition of a continuous representation, which can be helpful for training deep neural networks. We relate this to topological concepts such as homeomorphism and embedding. We then investigate what are continuous and discontinuous representations for 2D, 3D, and n-dimensional rotations. We demonstrate that for 3D rotations, all representations are discontinuous in the real Euclidean spaces of four or fewer dimensions. Thus, widely used representations such as quaternions and Euler angles are discontinuous and difficult for neural networks to learn. We show that the 3D rotations have continuous representations in 5D and 6D, which are more suitable for learning. We also present continuous representations for the general case of the n-dimensional rotation group SO(n). While our main focus is on rotations, we also show that our constructions apply to other groups such as the orthogonal group and similarity transforms. We finally present empirical results, which show that our continuous rotation representations outperform discontinuous ones for several practical problems in graphics and vision, including a simple autoencoder sanity test, a rotation estimator for 3D point clouds, and an inverse kinematics solver for 3D human poses.
Azide and Solvent Trapping of Electrophilic Intermediates Generated during the Hydrolysis of N-(Sulfonatooxy)-N-acetyl-4-aminostilbene

Hydrolysis of the carcinogenic title compound 1a in 5 vol % CH3CN−H2O, μ = 0.5, 20 °C at pH 7.2 in 0.02 M phosphate buffer, yields the rearranged material 3-(sulfonatooxy)-N-acetyl-4-aminostilbene (4) (23 ± 1%), threo-1,2-dihydroxy-1-phenyl-2-(4-acetamidophenyl)ethane (5) (57 ± 2%), and erythro-1,2-dihydroxy-1-phenyl-2-(4-acetamidophenyl)ethane (6) (20 ± 2%) in the absence of added nucleophiles. Addition of N3- has no effect on the rate constant for decomposition of 1a (ca. 1.9 × 10-2 s-1), but generates a number of adducts that result from trapping of three different electrophilic intermediates. The ortho-N3 adduct 3-azido-N-acetyl-4-aminostilbene (7) is produced from trapping of the nitrenium ion 2. A fit of the product yield data as a function of [N3-] provides the ratio kaz/ks of 280 ± 10 M-1 for competitive trapping of 2 by N3- and H2O. The nucleophilic aromatic substitution product 7 is a minor reaction product. The predominant site of attack by N3- on 2 (ca. 85%) is at the β-vinyl carbon to produce...
Toward the Synthesis of Extra-Large-Pore MCM-41 Analogues

A new approach is proposed for the synthesis of extra-large-pore (diameter > 7 nm) MCM-41 analogues, potentially useful as hosts for the synthesis of nanowires and as model porous solids for fundam...
Expanding the Remarkable Structural Diversity of Uranyl Tellurites: Hydrothermal Preparation and Structures of K[UO2Te2O5(OH)], Tl3{(UO2)2[Te2O5(OH)](Te2O6)}·2H2O, β-Tl2[UO2(TeO3)2], and Sr3[UO2(TeO3)2](TeO3)2

The reactions of UO(2)(C(2)H(3)O(2))(2).2H(2)O with K(2)TeO(3).H(2)O, Na(2)TeO(3) and TlCl, or Na(2)TeO(3) and Sr(OH)(2).8H(2)O under mild hydrothermal conditions yield K[UO(2)Te(2)O(5)(OH)] (1), Tl(3)[(UO(2))(2)[Te(2)O(5)(OH)](Te(2)O(6))].2H(2)O (2) and beta-Tl(2)[UO(2)(TeO(3))(2)] (3), or Sr(3)[UO(2)(TeO(3))(2)](TeO(3))(2) (4), respectively. The structure of 1 consists of tetragonal bipyramidal U(VI) centers that are bound by terminal oxo groups and tellurite anions. These UO(6) units span between one-dimensional chains of corner-sharing, square pyramidal TeO(4) polyhedra to create two-dimensional layers. Alternating corner-shared oxygen atoms in the tellurium oxide chains are protonated to create short/long bonding patterns. The one-dimensional chains of corner-sharing TeO(4) units found in 1 are also present in 2. However, in 2 there are two distinct chains present, one where alternating corner-shared oxygen atoms are protonated, and one where the chains are unprotonated. The uranyl moieties in 2 are bound by five oxygen atoms from the tellurite chains to create seven-coordinate pentagonal bipyramidal U(VI). The structures of 3 and 4 both contain one-dimensional [UO(2)(TeO(3))(2)](2-) chains constructed from tetragonal bipyramidal U(VI) centers that are bridged by tellurite anions. The chains differ between 3 and 4 in that all of the pyramidal tellurite anions in 3 have the same orientation, whereas the tellurite anions in 4 have opposite orientations on each side of the chain. In 4, there are also additional isolated TeO(3)(2-) anions present. Crystallographic data: 1, orthorhombic, space group Cmcm, a = 7.9993(5) A, b = 8.7416(6) A, c = 11.4413(8) A, Z = 4; 2, orthorhombic, space group Pbam, a = 10.0623(8) A, b = 23.024(2) A, c = 7.9389(6) A, Z = 4; 3, monoclinic, space group P2(1)/n, a = 5.4766(4) A, b = 8.2348(6) A, c = 20.849(3) A, beta = 92.329(1) degrees, Z = 4; 4, monoclinic, space group C2/c, a = 20.546(1) A, b = 5.6571(3) A, c = 13.0979(8) A, beta = 94.416(1) degrees, Z = 4.
Cs3AgAs4Se8 and CsAgAs2Se4: Selenoarsenates with Infinite 1∞[AsSe2]- Chains in Different Ag+ Coordination Environments

Two quaternary silver selenoarsenates Cs3AgAs4Se8 (I) and CsAgAs2Se4 (II) have been discovered by methanothermal reaction of Li3AsSe3 with AgBF4 in the presence of the respective alkali metal sources Cs2CO3 and CsCl. Orange crystals of Cs3AgAs4Se8 (I) were formed after reaction at 120 degrees C for 72 h, whereas red CsAgAs2Se4 (II) was obtained under slightly different conditions at 140 degrees C for 70 h. Both compounds possess novel two-dimensional (2D) polyanions consisting of infinite 1 infinity[AsSe2]- chains that are interconnected by Ag+ ions in different coordination patterns. In I, a double layer of 1 infinity[AsSe2]- chains is bridged by distorted trigonal planar coordinated Ag+ atoms to form a 2 infinity[AgAs4Se8]3- layer with a thickness of about 11.3 A. The nonbonding Ag...Ag distances are about 4.220 A, and large cavities within the layers accommodate for three of the four crystallographic Cs+ cations. The double amount of Ag+ atoms per AsSe2 chain unit in II leads to simple layers 2 infinity[AgAs2Se4]- [=[Ag2As4Se8]2-] in which the Ag+ atoms are arranged in rows between the 1 infinity[AsSe2]- chains, with alternating Ag...Ag distances of 3.053(3) and 3.488(3) A. Hereby the 1 infinity[AsSe2]- polyanions show a disorder within the central (-As-Seb)- chain (b = bridging), while the positions of the terminal Se atoms (Set) remain unaffected. The thermal, optical, and spectroscopic properties of the compounds are reported. Both I and II melt with decomposition and are wide band gap semiconductors with values of 2.07 and 1.79 eV, respectively. Raman spectroscopic data show typical band patterns expected for infinite [AsSe2]- chains. Crystal Data: Cs3AgAs4Se8 (I), monoclinic, C2/c, a = 25.212(2) A, b = 8.0748(7) A, c = 22.803(2) A, beta = 116.272(2) degrees, Z = 8; CsAgAs2Se4 (II), monoclinic, P2(1)/n, a = 10.9211(1) A, b = 6.5188(2) A, c = 13.7553(3) A, beta = 108.956(1) degrees, Z = 4.
Inverse electron-demand Diels–Alder chemistry in the synthesis of a regioselectively protected analogue of the staurosporine aglycone☆

Abstract Regioselective Weinreb amidation of the C1 ester of dimethyl pyridazino[4,5- b ]indole-1,4-dicarboxylate followed by an intramolecular inverse electron-demand Diels–Alder reaction and palladium-catalyzed coupling produced regioselectively protected N 6 -methylindolo[2,3- a ]pyrrolo[3,4- c ]carbazole ( N 6 -methylstaurosporinone).
BaAu2P4: layered zintl polyphosphide with infinite ∞(1)(P–) chains

Barium gold polyphosphide BaAu2P4 was synthesized from elements and structurally characterized by single crystal X-ray diffraction. BaAu2P4 crystallizes in a new structure type, in the orthorhombic space group Fddd (No. 70) with a = 6.517(1) A, b = 8.867(2) A, c = 21.844(5) A. The crystal structure of BaAu2P4 consists of Au–P layers separated by layers of Ba atoms. Each Au–P layer is composed of infinite ∞1(P–) chains of unique topology linked together by almost linearly coordinated Au atoms. According to Zintl–Klemm formalism, this compound is charge balanced assuming closed shell d10 configuration for Au: Ba2+(Au+)2(P–)4. Magnetic and solid state NMR measurements together with quantum-chemical calculations reveal diamagnetic and semiconducting behavior for the investigated polyphosphide, which is as expected for the charged balanced Zintl phase. Electron localization function and crystal orbital Hamilton population analyses reveal strong P–P and Au–P bonding and almost nonbonding Au–Au interactions in B...
Experimental Zika Virus Infection in the Pregnant Common Marmoset Induces Spontaneous Fetal Loss and Neurodevelopmental Abnormalities

During its most recent outbreak across the Americas, Zika virus (ZIKV) was surprisingly shown to cause fetal loss and congenital malformations in acutely and chronically infected pregnant women. However, understanding the underlying pathogenesis of ZIKV congenital disease has been hampered by a lack of relevant in vivo experimental models. Here we present a candidate New World monkey model of ZIKV infection in pregnant marmosets that faithfully recapitulates human disease. ZIKV inoculation at the human-equivalent of early gestation caused an asymptomatic seroconversion, induction of type I/II interferon-associated genes and proinflammatory cytokines, and persistent viremia and viruria. Spontaneous pregnancy loss was observed 16–18 days post-infection, with extensive active placental viral replication and fetal neurocellular disorganization similar to that seen in humans. These findings underscore the key role of the placenta as a conduit for fetal infection, and demonstrate the utility of marmosets as a highly relevant model for studying congenital ZIKV disease and pregnancy loss.
The power of observation

Abstract The critical role that observation can play in solving scientific problems is illustrated with several examples.
Preparation of enantioenriched tetraols and triolamines from a common epoxide

Abstract We identify a silylcyclopentene oxide that is amenable to several distinct asymmetric catalytic transformations providing access to enantio-enriched tetraol and triol-amines. The sequence employed allows for selective protection of one amine or alcohol from the four heteroatoms that are introduced into the carbon scaffold.
ANOMALY CANCELLATION: A RETROSPECTIVE FROM A MODERN PERSPECTIVE

The mechanism by which gauge and gravitational anomalies cancel in certain string theories is reviewed. The presentation is aimed at theorists who do not necessarily specialize in string theory.
Superconducting metamaterials for waveguide quantum electrodynamics

Embedding tunable quantum emitters in a photonic bandgap structure enables control of dissipative and dispersive interactions between emitters and their photonic bath. Operation in the transmission band, outside the gap, allows for studying waveguide quantum electrodynamics in the slow-light regime. Alternatively, tuning the emitter into the bandgap results in finite-range emitter–emitter interactions via bound photonic states. Here, we couple a transmon qubit to a superconducting metamaterial with a deep sub-wavelength lattice constant (λ/60). The metamaterial is formed by periodically loading a transmission line with compact, low-loss, low-disorder lumped-element microwave resonators. Tuning the qubit frequency in the vicinity of a band-edge with a group index of ng = 450, we observe an anomalous Lamb shift of −28 MHz accompanied by a 24-fold enhancement in the qubit lifetime. In addition, we demonstrate selective enhancement and inhibition of spontaneous emission of different transmon transitions, which provide simultaneous access to short-lived radiatively damped and long-lived metastable qubit states.
Microwave-assisted N-Boc deprotection under mild basic conditions using K3PO4·H2O in MeOH

Abstract A simple and efficient method for the deprotection of secondary Boc-protected amino compounds under mild basic conditions using K3PO4·H2O in MeOH assisted by microwave irradiation has been presented.
Crystal Structure and Properties of Ru-Stoichiometric LaSrMnRuO6

A stoichiometric LaSrMnRuO6 perovskite was synthesized by a modified sol−gel method. Special precautions were taken to minimize loss of ruthenium during the synthesis. LaSrMnRuO6 crystallizes with an orthorhombic perovskite structure in space group Imma determined by synchrotron powder X-ray diffraction; the Mn/Ru cations are disordered. A small amount of a Pmnb phase observed along with the major phase by electron diffraction transformed to Imma under the electron beam. X-ray absorption near-edge spectroscopy established the formal oxidation states as Mn3+ and Ru4+. Magnetic studies show ferromagnetic ordering at a Curie temperature of 225 K and an anomaly at 80 K. The magnetization, at 5 K in a field of 5 T, is not completely saturated and yields 2 μB per formula unit, much lower than the 6 μB expected. Electronic-transport measurements indicate semiconductor behavior with activation energies of 19.1 meV in the 230−380 K region and 22.7 meV in the 60−180 K region. A magnetoresistance of −6% is observed ...
New layered materials: syntheses, structures, and optical and magnetic properties of CsGdZnSe3, CsZrCuSe3, CsUCuSe3, and BaGdCuSe3.

Four new quaternary selenides CsGdZnSe3, CsZrCuSe3, CsUCuSe3, and BaGdCuSe3 have been synthesized with the use of traditional high-temperature solid-state experimental methods. These compounds are isostructural with KZrCuS3, crystallizing with four formula units in the orthorhombic space group Cmcm. Cell constants (A) at 153 K are CsGdZnSe3 4.1684(7), 15.765(3), 11.0089(18); CsZrCuSe3 3.903(2), 15.841(10), 10.215(6); CsUCuSe3 4.1443(7), 15.786(3), 10.7188(18); and BaGdCuSe3 4.1839(6), 13.8935(19), 10.6692(15). The structure of these ALnMSe3 compounds (A = Cs, Ba; Ln = Zr, Gd, U; M = Cu, Zn) is composed of [LnMSe3n-] (n = 1, 2) layers separated by A atoms. The Ln atom is octahedrally coordinated to six Se atoms, the M atom is tetrahedrally coordinated to four Se atoms, and the A atom is coordinated to a bicapped trigonal prism of eight Se atoms. Because there are no Se−Se bonds in the structure, the oxidation state of A is 1+ (Cs) or 2+ (Ba), that of Ln is 3+ (Gd) or 4+ (Zr, U), and that of M is 1+ (Cu) or...
On the contribution of active galactic nuclei to reionization (Research Note)

The electron scattering optical depth constraints on reionization suggest that there may be other sources that contribute to the ionization of hydrogen aside from observable star forming galaxies. Often the calculated value of the electron scattering optical depth, τ es , falls below the measurements derived from observations of the cosmic microwave background, or an assumption about non-observable sources must be made in order to reach agreement. Here, we calculate the hydrogen ionization fraction as a function of redshift and the electron scattering optical depth from both galaxies and active galactic nuclei (AGN) factoring in the secondary collisional ionizations from the AGN X-ray emission. In this paper we use the most current determination of the evolving hard X-ray luminosity function and extrapolate its evolution beyond z = 6. The AGN spectral energy distributions include both UV and X-ray ionizing photons. To search for the largest possible effect, all AGNs are assumed to have λ Edd = 1.0 and to be completely unobscured. The results show that AGNs produce a perturbative effect on the reionization of hydrogen and they remain in agreement with current constraints. Our calculations find the epoch of reionization still ends at z ≈ 6 and only increases the electron scattering optical depth by ~2.3% under ideal conditions. This can only be moderately increased by assuming a constant black hole mass of M BH = 105 M ⊙ . As a result, we conclude that there is a need for other sources beyond observable galaxies and AGNs that contribute to the reionization of hydrogen at z > 6.
Fluctuating environments select for short-term phenotypic variation leading to long-term exploration.

Genetic spaces are often described in terms of fitness landscapes or genotype-to-phenotype maps, where each genetic sequence is associated with phenotypic properties and linked to other genotypes that are a single mutational step away. The positions close to a genotype make up its “mutational landscape” and, in aggregate, determine the short-term evolutionary potential of a population. Populations with wider ranges of phenotypes in their mutational neighborhood are known to be more evolvable. Likewise, those with fewer phenotypic changes available in their local neighborhoods are more mutationally robust. Here, we examine whether forces that change the distribution of phenotypes available by mutation profoundly alter subsequent evolutionary dynamics. We compare evolved populations of digital organisms that were subject to either static or cyclically-changing environments. For each of these, we examine diversity of the phenotypes that are produced through mutations in order to characterize the local genotype-phenotype map. We demonstrate that environmental change can push populations toward more evolvable mutational landscapes where many alternate phenotypes are available, though purely deleterious mutations remain suppressed. Further, we show that populations in environments with harsh changes switch phenotypes more readily than those in environments with more benign changes. We trace this effect to repeated population bottlenecks in the harsh environments, which result in shorter coalescence times and keep populations in regions of the mutational landscape where the phenotypic shifts in question are more likely to occur. Typically, static environments select solely for immediate optimization, at the expensive of long-term evolvability. In contrast, we show that with changing environments, short-term pressures to deal with immediate challenges can align with long-term pressures to explore a more productive portion of the mutational landscape.
Approaches to the synthesis of arisugacin A

Abstract Approaches to the synthesis of the important acetylcholinesterase inhibitor, arisugacin A, are described. Two different routes to the key AB ring system are described: the first utilizes an intramolecular Diels–Alder reaction on a furan substrate and the second a 6π-electrocyclization of a substituted triene followed by cycloaddition with singlet oxygen. The successful synthesis of a fully functionalized AB ring system of arisugacin A, the tetraol 52 from hydroxy-β-ionone 22 in 16 steps and 9.3% overall yield is described. Several useful synthetic transformations to this molecule and its analogues are reported, e.g., the formation of the furan Diels–Alder cycloadduct 14 and its conversion into the oxa-bridged structures 17 and 21 , the preparation of the dienes 25 and 26 and the conversion of the later into the endoperoxide 30 and its diol 36 , the preparation of the endoperoxide 40 and the oxa-bridged system 42 , and finally the use of the enelactone 43 and its ultimately successful conversion into 52 . In addition, several novel rearrangements are described, producing the unusual compounds 62 , 65 , and 67 . Finally, the successful coupling of the pyrone unit to the AB ring system is described to give compounds 70 and 71 . The novel reduction of these compounds to the cyclic ether 74 is described.
Behavioral Effect of Chemogenetic Inhibition Is Directly Related to Receptor Transduction Levels in Rhesus Monkeys

We used inhibitory DREADDs (designer receptors exclusively activated by designer drugs) to reversibly disrupt dorsolateral prefrontal cortex (dlPFC) function in male rhesus monkeys. Monkeys were tested on a spatial delayed response task to assess working memory function after intramuscular injection of either clozapine-N-oxide (CNO) or vehicle. CNO injections given before DREADD transduction were without effect on behavior. rAAV5/hSyn-hM4Di-mCherry was injected bilaterally into the dlPFC of five male rhesus monkeys, to produce neuronal expression of the inhibitory (Gi-coupled) DREADD receptor. We quantified the percentage of DREADD-transduced cells using stereological analysis of mCherry-immunolabeled neurons. We found a greater number of immunolabeled neurons in monkeys that displayed CNO-induced behavioral impairment after DREADD transduction compared with monkeys that showed no behavioral effect after CNO. Even in monkeys that showed reliable effects of CNO on behavior after DREADD transduction, the number of prefrontal neurons transduced with DREADD receptor was on the order of 3% of total prefrontal neurons counted. This level of histological analysis facilitates our understanding of behavioral effects, or lack thereof, after DREADD vector injection in monkeys. It also implies that a functional silencing of a relatively small fraction of dlPFC neurons, albeit in a widely distributed area, is sufficient to disrupt spatial working memory.SIGNIFICANCE STATEMENT Cognitive domains such as working memory and executive function are mediated by the dorsolateral prefrontal cortex (dlPFC). Impairments in these domains are common in neurodegenerative diseases as well as normal aging. The present study sought to measure deficits in a spatial delayed response task following activation of viral-vector transduced inhibitory DREADD (designer receptor exclusively activated by designer drug) receptors in rhesus macaques and compare this to the level of transduction in dlPFC using stereology. We found a significant relationship between the extent of DREADD transduction and the magnitude of behavioral deficit following administration of the DREADD actuator compound clozapine-N-oxide (CNO). These results demonstrate it will be critical to validate transduction to ensure DREADDs remain a powerful tool for neuronal disruption.
Who are they and What do they Need: Characterizing and Supporting the Early Childhood Assistant Teacher Workforce in a Large Urban District.

Scholarship and policy emphasize strengthening the early childhood education (ECE) workforce, but this work neglects a large segment of the workforce: assistant teachers. This study responds to gaps in knowledge by examining the demographic characteristics, qualifications, professional supports, and workplace experiences of assistant teachers (N = 120) in a representative sample of ECE centers (n = 35) in a large urban district. In addition to studying assistant teachers' receipt of in-service training and coaching, we draw from social network theory to investigate the professional support assistant teachers provide and receive via their collegial networks. We use a variance decomposition approach to explore how on-the-job supports, such as training, coaching, and networks, contribute to assistant teachers' work-related stress and job satisfaction-two key predictors of ECE teacher attrition. Results indicate that few ECE staff members seek assistant teachers for work-related advice. Coaching is found to be an important contributor to assistant teachers' job satisfaction; professional advice via collegial networks is a meaningful but under-examined source of support for stress and job satisfaction. We consider implications for supporting and retaining assistant teachers and propose next steps for research on this understudied segment of the teaching workforce.
(3,4)-connected zincophosphites as structural analogues of zinc hydrogen phosphate.

The synthesis and crystal structures of three new open-framework zincophosphites with helical channels are reported here in the context of the synthetic design of an open architecture from three- and four-connected polyhedral centers. These zincophosphites were prepared under hydrothermal conditions from HF-containing media in mixed water−ethylene glycol solvents. Their three-dimensional frameworks consist of alternating ZnO46- tetrahedra and HPO32- trigonal pyramids with an overall framework composition of [Zn3(HPO3)4]2-. The topology was analyzed by converting these zincophosphites from their (3,4)-connected network into a four-connected framework. The symmetry and charge density of three different structure-directing agents dictate the symmetry and framework density of resulting inorganic frameworks. These zincophosphites are structural analogues of a known hydrogen phosphate, suggesting that the bonding difference between −P−H and −P−OH plays an insignificant role in the formation of phosphite and hyd...
Dynamical Generation of Solitons in a 1 + 1 Dimensional Chiral Field Theory:. Non-Perturbative Dirac Operator Resolvent Analysis

We analyze the 1 + 1 dimensional Nambu–Jona–Lasinio model non-perturbatively. We study non-trivial saddle points of the effective action in which the composite fields and form static space dependent configurations. These configurations may be viewed as one dimensional chiral bags that trap the original fermions ("quarks") into stable extended entities ("hadrons"). We provide explicit expressions for the profiles of some of these objects and calculate their masses. Our analysis of these saddle points, and in particular, the proof that the σ(x), π(x) condensations must give rise to a reflectionless Dirac operator, appear to us simpler and more direct than the calculations previously done by Shei, using the inverse scattering method following Dashen, Hasslacher, and Neveu.
Interactive phenotyping of large-scale histology imaging data with HistomicsML

Whole-slide imaging of histologic sections captures tissue microenvironments and cytologic details in expansive high-resolution images. These images can be mined to extract quantitative features that describe tissues, yielding measurements for hundreds of millions of histologic objects. A central challenge in utilizing this data is enabling investigators to train and evaluate classification rules for identifying objects related to processes like angiogenesis or immune response. In this paper we describe HistomicsML, an interactive machine-learning system for digital pathology imaging datasets. This framework uses active learning to direct user feedback, making classifier training efficient and scalable in datasets containing 108+ histologic objects. We demonstrate how this system can be used to phenotype microvascular structures in gliomas to predict survival, and to explore the molecular pathways associated with these phenotypes. Our approach enables researchers to unlock phenotypic information from digital pathology datasets to investigate prognostic image biomarkers and genotype-phenotype associations.
Experimental Test of Setting Three Contiguous Stereogenic Centers in Water. Diastereoselective Coupling of Geometrically Biased Allylic Bromides to α-Oxy Aldehydes with Indium

Indium-promoted additions of (Z)-2-(bromomethyl)-2-butenoate to several α-(tert-butyldimethylsiloxy) and α-(benzyloxy) aldehydes in water have been examined in order to assess the direction and sense of asymmetric induction in these coupling reactions. High levels of the 3,4-syn;4,5-anti diastereomers were produced, reflecting the promising synthetic potential of this chemistry. This stereodifferentiation has been attributed to the strong geometric bias exercised by this allylindium reagent and adherence to a Felkin−Ahn transition-state alignment. Support for this interpretation was gained by comparing the fate of (E)-cinnamyl bromide under comparable circumstances. In this case, the 3,4-anti;4,5-anti diastereomer predominated as expected.
Partitioned coalescence support reveals biases in species-tree methods and detects gene trees that determine phylogenomic conflicts

Abstract Genomic datasets sometimes support conflicting phylogenetic relationships when different tree-building methods are applied. Coherent interpretations of such results are enabled by partitioning support for controversial relationships among the constituent genes of a phylogenomic dataset. For the supermatrix (=concatenation) approach, several methods that measure the distribution of support and conflict among loci were introduced over 15 years ago. More recently, partitioned coalescence support (PCS) was developed for phylogenetic coalescence methods that account for incomplete lineage sorting and use the summed fits of gene trees to estimate the species tree. Here, we automate computation of PCS to permit application of this index to genome-scale matrices that include hundreds of loci. Reanalyses of four phylogenomic datasets for amniotes, land plants, skinks, and angiosperms demonstrate how PCS scores can be used to: (1) compare conflicting results favored by alternative coalescence methods, (2) identify outlier gene trees that have a disproportionate influence on the resolution of contentious relationships, (3) assess the effects of missing data in species-tree analysis, and (4) clarify biases in commonly-implemented coalescence methods and support indices. We show that key phylogenomic conclusions from these analyses often hinge on just a few gene trees and that results can be driven by specific biases of a particular coalescence method and/or the differential weight placed on gene trees with high versus low taxon sampling. The attribution of exceptionally high weight to some gene trees and very low weight to other gene trees counters the basic logic of phylogenomic coalescence analysis; even clades in species trees with high support according to commonly used indices (likelihood-ratio test, bootstrap, Bayesian local posterior probability) can be unstable to the removal of only one or two gene trees with high PCS. Computer simulations cannot adequately describe all of the contingencies and complexities of empirical genetic data. PCS scores complement simulation work by providing specific insights into a particular dataset given the assumptions of the phylogenetic coalescence method that is applied. In combination with standard measures of nodal support, PCS provides a more complete understanding of the overall genomic evidence for contested evolutionary relationships in species trees.
Multiplex RNA single molecule FISH of inducible mRNAs in single yeast cells

Transcript levels powerfully influence cell behavior and phenotype and are carefully regulated at several steps. Recently developed single cell approaches such as RNA single molecule fluorescence in-situ hybridization (smFISH) have produced advances in our understanding of how these steps work within the cell. In comparison to single-cell sequencing, smFISH provides more accurate quantification of RNA levels. Additionally, transcript subcellular localization is directly visualized, enabling the analysis of transcription (initiation and elongation), RNA export and degradation. As part of our efforts to investigate how this type of analysis can generate improved models of gene expression, we used smFISH to quantify the kinetic expression of STL1 and CTT1 mRNAs in single Saccharomyces cerevisiae cells upon 0.2 and 0.4 M NaCl osmotic stress. In this Data Descriptor, we outline our procedure along with our data in the form of raw images and processed mRNA counts. We discuss how these data can be used to develop single cell modelling approaches, to study fundamental processes in transcription regulation and develop single cell image processing approaches. Machine-accessible metadata file describing the reported data (ISA-Tab format)
A New Superstructure for the BaAl4-Structure Type: An Experimental and Theoretical Study of La2NiAl7

A new ternary aluminide, La2NiAl7, has been synthesized from the elements in sealed silica tubes. The crystal structure of La2NiAl7 was determined by single-crystal X-ray diffraction and crystalliz...
SURFACE MAGNETISM OF GADOLINIUM

The surface magnetism of Gd exhibits a variety of unusual phenomena. This is not to say the book has been closed on the bulk properties. Indeed, characterization of the single crystal critical behavior is an ongoing field. In this light, it is not surprising that studies of the surface magnetic properties of Gd have lagged those of the transition metal magnets. The delay has primarily been due to the difficulty in obtaining a sufficiently pure sample. We report on the methods available for creating an atomically clean surface, the newly measured surface structure, the hows and whys of the surface enhanced magnetic order displayed by Gd and finally lay to rest the possibility of antiparallel coupling of the surface layer to the bulk.
Mechanism of Dihydrogen Formation in the Magnesium−Water Reaction⊥

The thermodynamically favored reaction between water and magnesium, Mg + 2H2O → Mg(OH)2 + H2, is normally sluggish, but it becomes reasonably rapid when a milled composite of powdered magnesium met...