cssi/SciSciGPT-SciSciNet huggingface dataset:
Distributed Transient Frequency Control in Power Networks

Modern power networks face increasing challenges in controlling their transient frequency behavior at acceptable levels due to low inertia and highly-dynamic units. This paper presents a distributed control strategy regulated on a subset of buses in a power network to maintain their transient frequencies in safe regions while preserving asymptotic stability of the overall system. Building on Lyapunov stability and set invariance theory, we formulate the transient frequency requirement and the asymptotic stability requirement as two separate constraints for the control input. Hereby, for each bus of interest, we synthesize a controller satisfying both constraints simultaneously. The controller is distributed and Lipschitz, guaranteeing the existence and uniqueness of the trajectories of the closed-loop system. Simulations on the IEEE 39-bus power network illustrate the results.
The carceral side of freedom

When nationalistic narratives implore citizens to recall progressive values in their history, as some American politicians have in the recent past, do we also remember the cost, and those at whose ...
Corporate Governance and Firm Survival

We explore how various aspects of corporate governance influence the likelihood of a public corporation surviving as a separate public entity, after addressing potential endogeneity that arises from competing corporate exit outcomes: acquisitions, goingâ€ private transactions, and bankruptcies. We find that some corporate governance features are more important determinants of the form of a firm's exit than many economic factors that have figured prominently in prior research. We also find evidence that outsiderâ€ dominated boards and lower restrictions on internal governance play major roles in the way firms exit public markets, particularly when a firm's industry suffers a negative shock. Overall, our results suggest that failure to recognize competing risks produces biased estimates, resulting in faulty inferences.
Spectroscopic Investigation of Yb -Doped Silica Glass for Solid-State Optical Refrigeration

$R\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}d\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n$ $b\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}g$ is a viable technique for heat mitigation in lasers and amplifiers, relying on anti-Stokes fluorescence cooling to offset heat generation in the gain medium. To achieve radiation balancing, the gain medium should be amenable to solid-state optical refrigeration. As Yb-doped silica is the gain medium of choice for most fiber lasers and amplifiers, it is important to determine whether this material can be optically cooled. The authors use optical spectroscopy to explore the possibility of solid-state optical refrigeration of Yb-doped silica, and show that cooling is in fact feasible.
Setting the transgender agenda: intermedia agenda-setting in the digital news environment

Transgender issues have recently emerged as highly salient topics of political contestation in the United States. This paper investigates one relevant factor in that ascent: intermedia agenda-setti...
Virtual, 3-Dimensional Temporal Bone Model and Its Educational Value for Neurosurgical Trainees

Objective Learning complex neuroanatomy is an arduous yet important task for every neurosurgical trainee. As technology has advanced, various modalities have been created to aid our understanding of anatomy. This study sought to assess the educational value of a virtual, 3-dimensional (3D) temporal bone model. Methods The 3D temporal bone model was created with assistance of computer graphic designers and published online. Its educational value as a teaching was tool was assessed by querying 73 neurosurgery residents at 4 institutions and was compared with that of a standard, 2-dimensional (2D) temporal bone resource. Data were collected via a survey, and significance among responses was analyzed via a univariate chi-square test. Results The survey response rate was 37%. Greater than 90% of residents preferred to study with the 3D model compared with the 2D resource and felt that the 3D model allowed them understand the anatomy more realistically (P = 0.001). Moreover, >90% of residents believed that reviewing the 3D model before an actual surgery could lead to improved operative efficiency and safety (P = 0.001). Conclusions This study demonstrates the utility of a novel, 3D temporal bone model as a teaching tool for neurosurgery residents. The model contains accurate anatomic structures and allows user interaction via a virtual, immersive environment.
Developing a Measure of Spanish Phonological Awareness for Preschool Age Children: Spanish Individual Growth and Development Indicators

Spanish speakers in the United States are a steadily increasing population, up by 233% since 1980. Given the growing population of dual language learners (DLLs) and the large numbers of Spanish-spe...
Overparameterized Nonlinear Learning: Gradient Descent Takes the Shortest Path?

Many modern learning tasks involve fitting nonlinear models to data which are trained in an overparameterized regime where the parameters of the model exceed the size of the training dataset. Due to this overparameterization, the training loss may have infinitely many global minima and it is critical to understand the properties of the solutions found by first-order optimization schemes such as (stochastic) gradient descent starting from different initializations. In this paper we demonstrate that when the loss has certain properties over a minimally small neighborhood of the initial point, first order methods such as (stochastic) gradient descent have a few intriguing properties: (1) the iterates converge at a geometric rate to a global optima even when the loss is nonconvex, (2) among all global optima of the loss the iterates converge to one with a near minimal distance to the initial point, (3) the iterates take a near direct route from the initial point to this global optima. As part of our proof technique, we introduce a new potential function which captures the precise tradeoff between the loss function and the distance to the initial point as the iterations progress. For Stochastic Gradient Descent (SGD), we develop novel martingale techniques that guarantee SGD never leaves a small neighborhood of the initialization, even with rather large learning rates. We demonstrate the utility of our general theory for a variety of problem domains spanning low-rank matrix recovery to neural network training. Underlying our analysis are novel insights that may have implications for training and generalization of more sophisticated learning problems including those involving deep neural network architectures.
Design and Implementation of Position Sensorless Starting Control in Industrial Drives With Output Filter and Transformer for Oil/Pump Applications

An open velocity loop current regulated sensorless control scheme for both induction and permanent magnetic motor drives with an output sine wave filter and transformer is designed and implemented in this paper. The proposed control scheme provides a low-voltage drive solution for driving medium-voltage motors without substantially oversizing the inverter. Sufficient starting torque is guaranteed with controlled drive and motor current. Laboratory proof-of-concept tests and experimental results on an actual deep well have validated the effectiveness of the proposed control scheme
ARM: Augment-REINFORCE-Merge Gradient for Stochastic Binary Networks.

To backpropagate the gradients through stochastic binary layers, we propose the augment-REINFORCE-merge (ARM) estimator that is unbiased, exhibits low variance, and has low computational complexity. Exploiting variable augmentation, REINFORCE, and reparameterization, the ARM estimator achieves adaptive variance reduction for Monte Carlo integration by merging two expectations via common random numbers. The variance-reduction mechanism of the ARM estimator can also be attributed to either antithetic sampling in an augmented space, or the use of an optimal anti-symmetric "self-control" baseline function together with the REINFORCE estimator in that augmented space. Experimental results show the ARM estimator provides state-of-the-art performance in auto-encoding variational inference and maximum likelihood estimation, for discrete latent variable models with one or multiple stochastic binary layers. Python code for reproducible research is publicly available.
On the hydrodynamics of crystal clustering.

The formation of crystal clusters may influence the mechanical behaviour of magmas. However, whether clusters form largely from physical contact in a mobile state during sedimentation and stirring,...
Cyber-physical simulation and optimal mitigation for shipping port operations

Modern shipping ports require computer systems to accommodate an increasing number of port calls, larger vessel sizes, and tighter supply chains. Disruptions to assets on these networks have the potential to propagate to other critical infrastructures at great economic cost. Such disruptions may be introduced intentionally by adversaries that include nation states, organized crime, hacktivists, and insiders. Area Maritime Security Committees (AMSCs) must develop security plans to minimize disruptions' impact. This paper explores one way to couple a simulation of the flow of commodities through a shipping port with an optimization that minimizes the cost of disruptions to the port transportation system. Our intent is to enable stakeholders to run what-if scenarios, to understand the impact and effect of cyber-physical disruptions, and to optimally mitigate their effect. This research, based on ongoing fieldwork with Port Everglades and the USCG, hopes to improve security policies that integrate cyber and physical effects.
La poética ritual en lulú de ana harcha: Una trayectoria rítmica y circular

espanolLeer la obra Lulu de Ana Harcha a partir de una ritualidad poetica es entenderla como la trayectoria circular y religiosa que emprende su protagonista con el objetivo de hacer emerger una subjetividad otra, conjurando con ello las escisiones del pensamiento racional. En el contexto de la obra esta trayectoria se configura a traves de los recursos retoricos del ritmo y las imagenes mitico-circulares, recursos que despliegan un principio unificador epistemico y estetico. De este modo, la protagonista de Lulu se nos presenta como una santa pagana que establece vinculos con saberes y expresiones negados y subvalorados por el logos occidental. EnglishTo read the work Lulu of Ana Harcha from a poetic rituality, is to understand it as the circular and religious trajectory that its protagonist undertakes with the aim of making emerge another subjectivity, conjuring with it the splits of rational thought. In the context of the work, this trajectory is configured through the rhetorical resources of the rhythm and the mythical-circular images, resources that deploy an unifying epistemic and aesthetic principle. In this way, the protagonist of Lulu appears to us as a pagan saint who establishes links with knowledge and expressions denied and undervalued by the western logos.
Opposing Influence of Sensory and Motor Cortical Input on Striatal Circuitry and Choice Behavior.

Summary The striatum is the main input nucleus of the basal ganglia and is a key site of sensorimotor integration. While the striatum receives extensive excitatory afferents from the cerebral cortex, the influence of different cortical areas on striatal circuitry and behavior is unknown. Here, we find that corticostriatal inputs from whisker-related primary somatosensory (S1) and motor (M1) cortex differentially innervate projection neurons and interneurons in the dorsal striatum and exert opposing effects on sensory-guided behavior. Optogenetic stimulation of S1-corticostriatal afferents in ex vivo recordings produced larger postsynaptic potentials in striatal parvalbumin (PV)-expressing interneurons than D1- or D2-expressing spiny projection neurons (SPNs), an effect not observed for M1-corticostriatal afferents. Critically, in vivo optogenetic stimulation of S1-corticostriatal afferents produced task-specific behavioral inhibition, which was bidirectionally modulated by striatal PV interneurons. Optogenetic stimulation of M1 afferents produced the opposite behavioral effect. Thus, our results suggest opposing roles for sensory and motor cortex in behavioral choice via distinct influences on striatal circuitry.
A Navigational Approach to Health: Actionable Guidance for Improved Quality of Life

Health and well-being are shaped by how lifestyle and the environment interact with biological machines. A navigational paradigm can help users reach a specific health goal by using constantly captured measurements to estimate how their health is continuously changing and provide actionable guidance.
Studies on the Stereoselective Synthesis of the Marine Antitumor Agent Eleutherobin

Abstract (+)-Carvone has been converted into the sulfone 14 which comprises the left-hand side of the cytotoxic sesquiterpene, eleutherobin 1 . Julia coupling of 14 to the aldehyde 21 , followed by oxidation, dissolving metal reduction and stereoselective reduction of the C8 carbonyl group resulted in 29 , which has the correct stereochemistry at C8 and C9. Further conversion of 29 into 37 , and attempted intramolecular cyclization resulted in fragmentation to the furan 39 and 38 . Asymmetric epoxidation of the allylic alcohols 42 and 48 resulted in neighboring group participation from the adjacent dimethoxy acetal and formation of the rearranged oxepane derivatives 44 , 45 and 49 , respectively.
Highly Enantioselective Oxidation of cis-Cyclopropylmethanols to Corresponding Aldehydes Catalyzed by Chloroperoxidase

Chloroperoxidase (CPO) catalyzes the enantioselective oxidation of cyclopropylmethanols, such as 2-methylcyclopropylmethanol, to cyclopropyl aldehydes using tert-butyl hydroperoxide as the terminal oxidant. In all cases, CPO oxidation of cis-cyclopropanes shows much higher enantioselectivity than with the trans isomers, although CPO gives similar catalytic activity on both isomers. This presents the first example for a heme enzyme that catalyzes the enantioselective oxidation of cyclopropylmethanols. This finding enables a novel route to the synthesis of optically active cyclopropane derivatives, which occur widely in natural products and compounds of pharmaceutical interest. In addition, chiral cyclopropane molecules may be useful model substrates to investigate reaction mechanisms of CPO and the related cytochromes P450.
Bismuth trichloride catalyzed synthesis of α-aminonitriles

A simple and efficient one-pot method has been developed for the synthesis of α-aminonitriles from aldehydes, amines, and trimethylsilyl cyanide in the presence of a catalytic amount of bismuth trichloride.
Reduced Protein Expression in a Virus Attenuated by Codon Deoptimization

A general means of viral attenuation involves the extensive recoding of synonymous codons in the viral genome. The mechanistic underpinnings of this approach remain unclear, however. Using quantitative proteomics and RNA sequencing, we explore the molecular basis of attenuation in a strain of bacteriophage T7 whose major capsid gene was engineered to carry 182 suboptimal codons. We do not detect transcriptional effects from recoding. Proteomic observations reveal that translation is halved for the recoded major capsid gene, and a more modest reduction applies to several coexpressed downstream genes. We observe no changes in protein abundances of other coexpressed genes that are encoded upstream. Viral burst size, like capsid protein abundance, is also decreased by half. Together, these observations suggest that, in this virus, reduced translation of an essential polycistronic transcript and diminished virion assembly form the molecular basis of attenuation.
ASYMMETRIC CONSTRUCTION OF A QUATERNARY CARBON CENTER BY TANDEM 4 + 2/3 + 2 CYCLOADDITION OF A NITROALKENE. THE TOTAL SYNTHESIS OF (-)-MESEMBRINE

An efficient, total synthesis of the Sceletium alkaloid (−)-mesembrine is accomplished in seven steps and 19% yield from a functionalized nitroalkene (itself prepared in six steps and 34% yield from ethyl 3-bromopropionate). The construction of the octahydroindole framework of mesembrine features a tandem inter [4 + 2]/intra [3 + 2] cycloaddition of a 2,2-disubstituted 1-nitroalkene and a chiral vinyl ether derived from (1R,2S)-2-(1-methyl-1-phenylethyl)cyclohexanol as the central strategic element. The two stereogenic centers of the natural product, which include a benzylic, quaternary center, were established in 26/1 selectivity in the tandem process.
QUEST FOR THE PENTAGONAL DODECAHEDRANE

An account of two synthetic approaches to the pentagonal dodecahedrane based upon the “pincer” Diels-Alder reaction of 9,10-dihydrofulvalene and dimethyl acetylenedicarboxylate is given. In both schemes, the strategem calls for the maintenance of symmetry in all intermediates as a means of minimizing the total number of requisite synthetic manipulations and permitting maximum utilization of l3C NMR spectroscopy.
Porphyrins with β,β'-fused five-membered rings

Recent studies involving porphyrin systems bearing fused five-membered rings are reviewed, these including pyrrolo[3,4-b]porphyrins and fused metallocenoporphyrins. Diels-Alder cycloadditions between pyrroloporphyrins, to give benzoporphyrins, are discussed. The syntheses of mono-, and the two regioisomers (adj- and opp-) of bis-sulfolenoporphyrins are then discussed and their reactions with dienophiles such as dimethyl acetylenedicarboxylate are outlined.
Surface structure of quark stars with magnetic fields

We investigate the impact of magnetic fields on the electron distribution of the electrosphere of quark stars. For moderately strong magnetic fields of B ∼ 1013 G, quantization effects are generally weak due to the large number density of electrons at surface, but can nevertheless affect the photon emission properties of quark stars. We outline the main observational characteristics of quark stars as determined by their surface emission, and briefly discuss their formation in explosive events termed as quark-novae, which may be connected to the r-process.
Bergman cycloaromatization of imidazole-fused enediynes: the remarkable effect of N-aryl substitution

A series of N-aryl substituted 'imidazole-fused' (Z) 3-ene-1,5-diynes was prepared and kinetic parameters for their Bergman cycloaromatization reactivities were determined. N-Arylation enhanced rates relative to N-alkyl derivatives by up to sevenfold (ANOVA p < 0.0001). The greatest enhancement was exhibited by the N-phenyl derivative (sevenfold at 145 °C).
One-pot synthesis of unsymmetrical triarylamines from aniline precursors.

The “one-pot” synthesis of triarylamines from an aniline and two different aryl halides is described. A catalytic system composed of Pd2(dba)3/P(t-Bu)2-o-biphenyl (1) is used to prepare a variety of triarylamines in a single flask by the coupling of an aniline with an aryl bromide and aryl chloride. The synthesis of triarylamines containing a heterocyclic aryl group is also described by employing a one-flask, two-step method. These methods can be used to synthesize both discrete triarylamines and a triarylamine library.
Structural and spectroscopic trends in actinyl iodates of uranium, neptunium, and plutonium.

Two neptunyl(VI) iodates, NpO2(IO3)2(H2O) (1) and NpO2(IO3)2·H2O (2), have been prepared from the aqueous reactions of Np(V) in HCl with KIO4 or H5IO6 at 180 °C and have been characterized by single crystal X-ray diffraction and Raman spectroscopy. Both compounds consist of two-dimensional arrangements of pentagonal bipyramidal [NpO7] polyhedra with axial neptunyl, NpO22+, dioxocations. In 1, the neptunium centers are bound in the equatorial plane by four bridging iodate anions and one terminal water molecule. The iodate anions link the [NpO7] units into corrugated sheets that interact with one another through intermolecular IO3-···IO3- interactions as also observed in UO2(IO3)2(H2O). Compound 2 is isostructural with the recently reported PuO2(IO3)2·H2O, where oxygen atoms from bridging iodate anions occupy the five equatorial sites around the neptunyl moieties. The iodate anions occur as both μ2- and μ3-units and link the neptunyl polyhedra into sheets. Both types of iodate anions have their stereochemic...
Design of Cancer-Specific Antitumor Agents Based on Aziridinylcyclopent[b]indoloquinones

The merits of N-unsubstituted indoles and cyclopent[b]indoles as DNA-directed reductive alkylating agents are described. These systems represent a departure from N-substituted and pyrrolo[1,2-a]-fused systems such as the mitomycins and mitosenes. The cyclopent[b]indole-based aziridinylquinone system, when bearing an acetate leaving group with or without an N-acetyl group, was cytotoxic and displayed significant in vivo activity against syngeneic tumor implants. These analogues were superior to the others studied in terms of both high specificity for the activating enzyme DT-diaphorase and high percent DNA alkylation. Alkylation by a quinone methide intermediate as well as by the aziridinyl group could lead to cross-linking. The possible metabolites of the most active indole species were prepared and found to retain cytotoxicity, suggesting that in vivo activity could be sustained. The indole systems in the present study display selectivity for melanoma and, depending on the substituents present, selectivi...
New Routes to Transition Metal-Carbido Species: Synthesis and Characterization of the Carbon-Centered Trigonal Prismatic Clusters [W6CCl18]n- (n = 1, 2, 3)

Simultaneous reduction of WCl6 and CCl4 with bismuth metal at 400 °C affords a black solid, from which the new cluster [W6CCl18]2- is extracted into aqueous HCl. The cluster is isolated in 34% yield as (Bu4N)2[W6CCl18] and features a metal−metal bonded W6 trigonal prism centered by a carbon atom and surrounded by 12 edge-bridging and 6 terminal chloride ligands. A cyclic voltammogram of [W6CCl18]2- in DMF shows the cluster undergoes two reduction and two oxidation processes, suggesting five chemically accessible redox states. Consistent with this extensive electrochemistry, DFT calculations on the diamagnetic [W6CCl18]2- species reveal closely spaced frontier orbitals, with an a2‘ ‘ HOMO situated 0.61 and 0.71 eV below unoccupied e‘ ‘ and e‘ orbitals, respectively. Oxidation of the cluster by a single equivalent of NO+ gives [W6CCl18]1-, which, as expected on the basis of the [W6CCl18]2- HOMO character, possesses a less elongated W6 trigonal prism. Reduction of [W6CCl18]2- with a single equivalent of coba...
Hypervalent Ammonium Radicals. Effects of Alkyl Groups and Aromatic Substituents

Neutralization by collisional electron transfer of gaseous benzylalkylammonium ions produces transient hypervalent radicals whose dissociations depend on the substituents in the aromatic ring and at the amine nitrogen atom. Benzylammonium radical, C6H5CH2NH3•, dissociates mainly by N−H bond cleavage to give benzylamine. Dissociation of the CH2−N bond to benzyl radical and ammonia is less abundant. Benzylmethylammonium, C6H5CH2NH2CH3•, dissociates by CH2−N, N−CH3, and N−H bond cleavages to give methylamine, benzyl radical, benzylamine, and N-methylbenzylamine. Benzyldimethylammonium, C6H5CH2NH(CH3)2•, undergoes loss of dimethylamine and hydrogen, while the loss of methyl is less important. (2,3,4,5,6-Pentafluorobenzyl)dimethylammonium radical, C6F5CH2NH(CH3)2•, dissociates mainly by fission of the pentafluorophenyl ring to give CnFm fragments with CF• as the dominating product, while bond dissociations at the hypervalent nitrogen atom are less important. The relative stabilities of pentafluorobenzyl and tr...
Selective 4-arylation of pyridines by a nonmetalloorganic process.

Mild and position-selective nucleophilic 4-arylation of pyridines has been accomplished by the use of triflic anhydride N-activation.
A shock tube study of the reactions of the hydroxyl radical with several combustion species

Reactions of the hydroxyl radical, OH, with several organic species of interest in combustion chemistry have been studied near 1200 K and 1 atm in shock tube experiments in which UV absorption was used to monitor the OH concentration. Rate coefficients were measured for the reactions of OH with 2,3-dimethylbutane, isooctane, neooctane, ethylene, propylene, acetylene, formaldehyde, methanol, and ethanol. The values were found to be (in units of 1012 cm3/mol-s): 21, 22, 18, 2.6, 9.6, 0.28, 12, 5.2, and 5.3. These measured values are compared with previous experimental results and, where appropriate, transition-state theory calculations.
Taking Other Religions Seriously: A Comparative Survey of Hindus in India

While the study of religion in political science has reemerged as a growing field of inquiry in the last few decades, most research still focuses on Judaism, Christianity, and Islam. What religion is and how it is measured has largely been conceptualized through the lens of these Abrahamic faiths. This article, by contrast, examines Hinduism, the world's oldest and third most populous religion. I randomly assigned closed-ended or open-ended surveys about Hindu religiosity across and within two demographically similar villages in the north Indian state of Bihar. A comparison of survey responses from a sample of 100 respondents suggests that many Hindus: (a) do not recognize basic analytical categories scholars use in the social scientific study of religion; (b) do not differentiate between ostensibly religious and secular categories; and (c) recognize features of everyday life, such as attire or obedience to rules about purity and auspiciousness, as religious in ways that may be different from most Western religious communities. This article productively challenges how political scientists think about what religion is and how to measure it, tasks that must precede explaining how it affects political behavior.
Genetic Regulatory Mechanisms of Smooth Muscle Cells Map to Coronary Artery Disease Risk Loci

Coronary artery disease (CAD) is the leading cause of death globally. Genome-wide association studies (GWASs) have identified more than 95 independent loci that influence CAD risk, most of which reside in non-coding regions of the genome. To interpret these loci, we generated transcriptome and whole-genome datasets using human coronary artery smooth muscle cells (HCASMCs) from 52 unrelated donors, as well as epigenomic datasets using ATAC-seq on a subset of 8 donors. Through systematic comparison with publicly available datasets from GTEx and ENCODE projects, we identified transcriptomic, epigenetic, and genetic regulatory mechanisms specific to HCASMCs. We assessed the relevance of HCASMCs to CAD risk using transcriptomic and epigenomic level analyses. By jointly modeling eQTL and GWAS datasets, we identified five genes (SIPA1, TCF21, SMAD3, FES, and PDGFRA) that may modulate CAD risk through HCASMCs, all of which have relevant functional roles in vascular remodeling. Comparison with GTEx data suggests that SIPA1 and PDGFRA influence CAD risk predominantly through HCASMCs, while other annotated genes may have multiple cell and tissue targets. Together, these results provide tissue-specific and mechanistic insights into the regulation of a critical vascular cell type associated with CAD in human populations.
On the existence of Ca2Bi-crystal and electronic structure of Ca4Bi2O

Abstract Reported are the structure refinements and the electronic structure calculations for the ternary compound Ca 4 Bi 2 O, up until now erroneously known as the binary Ca 2 Bi. Ca 4 Bi 2 O crystallizes in the body-centered tetragonal space group I 4/ mmm (no. 139), with cell parameters a = 4.719(2) A and c = 16.505(9) A at 120 K, and its structure can be regarded as built of oxygen-centered octahedra of Ca, forming infinite layers via corner sharing, i.e. as an anti-type of the perovskite-related K 2 NiF 4 . The bonding in Ca 4 Bi 2 O has been further analyzed using electronic structure calculations (LMTO-ASA), which confirm that Ca 4 Bi 2 O and related phases, as expected, are closed-shell compounds.
Aminonitropyridines and their N-oxides†

2,6-Diamino-3,5-dinitropyridine 1-oxide has been prepared by mixed acid nitration of 2,6-diaminopyridine, followed by oxidation using hydrogen peroxide in acetic acid. 3,5-Dinitro-2,4,6-triaminopyridine has been prepared by oxidative amination of 2-chloro-3,5-dinitropyridine or 2,6-diamino-3,5-dinitropyridine using potassium permanganate in liquid ammonia, or by “vicarious nucleophilic amination” of 2,6-diarnino-3,5-dinitropyridine using hydroxylamine in aqueous potassium hydroxide. 3,5-Dinitro-2,4,6-triaminopyridine 1-oxide has been prepared by oxidation of 3,5-dinitro-2,4,6-triaminopyridine using hydrogen peroxide in acetic acid, and by “vicarious nucleophilic amination” of 2,6-diamino-3,5-dinitropyridine 1-oxide. Nmr spectroscopy and single crystal X-ray diffraction studies have shown that these compounds have the planar structures and intra- and inter-molecular hydrogen bonding necessary to confer on the materials the high density, the thermal and chemical stability, and the explosive insensitivity required for new insensitive energetic materials.
Biradicals from Thermolysis of N-[2-(1-Alkynyl)phenyl]-N'-phenylcarbodiimides and Their Subsequent Transformations to 6H-Indolo[2,3-b]quinolines.

Thermolysis of the carbodiimide 9a in γ-terpinene at 138 °C produced 2-(phenylamino)quinoline (11a, 49%) and the parent 6H-indolo[2,3-b]quinoline (14a, 16%). Apparently, 11a was produced via the biradical 10a followed by hydrogen-atom abstraction from γ-terpinene. A two-step biradical pathway through 12a or a one-step intramolecular Diels−Alder reaction could furnish 13a, which then underwent tautomerization to give 14a. With the carbodiimide 9b having a trimethylsilyl substituent at the acetylenic terminus, thermolysis in refluxing p-xylene at 138 °C produced the 6H-indolo[2,3-b]quinoline 14b (86%) exclusively. Treatment of 14b with 6 N NaOH in refluxing ethanol then furnished 14a in 92% yield. Similarly, the 6H-indolo[2,3-b]quinolines 14c−f were obtained from thermolysis of the carbodiimides 9c−f. The use of the aza-Wittig reaction between 4-methoxyphenyl isocyanate and the iminophosphoranes 2d and 2f to produce the corresponding carbodiimides followed by thermolysis furnished the 6H-indolo[2,3-b]quinol...
Influence of Chemisorbed Oxygen on the Growth of Graphene on Cu(100) by Chemical Vapor Deposition

Understanding the influence that copper substrate surface symmetry and oxygen impurities have on the growth of graphene by chemical vapor deposition is important for developing techniques for producing high-quality graphene. Therefore, we have studied the growth of graphene by catalytic decomposition of ethylene in an ultrahigh-vacuum chamber on both a clean Cu(100) surface and a Cu(100) surface predosed with a layer of chemisorbed oxygen. The crystal structure of the graphene films was characterized with in situ low energy electron diffraction. By heating the clean Cu(100) substrate from room temperature to the growth temperature in ethylene, epitaxial graphene films were formed. The crystal quality was found to depend strongly on the growth temperature. At 900 °C, well-ordered two-domain graphene films were formed. Predosing the Cu(100) surface with a chemisorbed layer of oxygen before graphene growth was found to adversely affect the crystal quality of the graphene overlayer by inducing a much higher d...
Molecular mechanisms of regulation of type I collagen biosynthesis

Type I collagen is a heterotrimeric protein composed of twoα1(I) and oneα2(I) polypeptide chains, each encoded by a unique gene. Both collagen genes are coordinately regulated in response to a variety of endogenous and exogenous stimuli. Collagen genes are mainly regulated by transcriptional mechanisms, although post-transcriptional regulatory mechanisms have occasionally been documented. To understand the molecular basis of transcriptional control, we have been studying thecis-regulatory sequence motifs of human Proα1(I) collagen gene andtrans-acting factors with which these elements interact. The major elements include TATA and CCAAT boxes, Ap-1, Ap-2, NF-1 and Sp1, and a unique TGFβ1-activating element. Transcription factor Sp1 is obligatory for the activation of the Proα1(I) promoter since it failed to be activated inDrosophila SL2 cells that lack Sp1. Of the six putative Sp1 motifs in the Proα1(I) collagen promoter and the first intron, the most proximal Sp1 element located at −87 to −82 bp was sufficient for its Sp1-dependent activation. Additionalcis-acting motifs in the intron of the Proα1(I) gene, including an Ap-1 site, participated in its regulation by TGFβ1 and okadaic acid. Thus, activation of Proα1(I) promoter involves combinatorial actions of multiple ubiquitous and uniquecis-regulatory elements.
Molecular die catalysis: Hexane aromatization over Pt/KL

Abstract Pt/KL contrasts with Pt/SiO 2 in having: (1) a much greater selectivity for hexane aromatization; (2) a strong preference for cracking the terminal carbon—carbon bond as opposed to interior bonds. These properties, taken together, suggest enhanced terminal adsorption of the hexane molecule at the Pt surface. Pt/high-silica faujasite has similar characteristics. We believe the fact that Pt in both these zeolites is accessible only through portholes of ∼7.3 A is a critical feature which leads to these unusual properties.
Effect of tether position on the intramolecular reaction between rhodium stabilized carbenoids and furans

Abstract The product distribution from the intramolecular reaction between carbenoids and furans is strongly influenced by the position of the linking tether on the furan.
Deep sequencing of natural and experimental populations of Drosophila melanogaster reveals biases in the spectrum of new mutations

Mutations provide the raw material of evolution, and thus our ability to study evolution depends fundamentally on having precise measurements of mutational rates and patterns. We generate a data set for this purpose using (1) de novo mutations from mutation accumulation experiments and (2) extremely rare polymorphisms from natural populations. The first, mutation accumulation (MA) lines are the product of maintaining flies in tiny populations for many generations, therefore rendering natural selection ineffective and allowing new mutations to accrue in the genome. The second, rare genetic variation from natural populations allows the study of mutation because extremely rare polymorphisms are relatively unaffected by the filter of natural selection. We use both methods in Drosophila melanogaster, first generating our own novel data set of sequenced MA lines and performing a meta-analysis of all published MA mutations (∼2000 events) and then identifying a high quality set of ∼70,000 extremely rare (≤0.1%) polymorphisms that are fully validated with resequencing. We use these data sets to precisely measure mutational rates and patterns. Highlights of our results include: a high rate of multinucleotide mutation events at both short (∼5 bp) and long (∼1 kb) genomic distances, showing that mutation drives GC content lower in already GC-poor regions, and using our precise context-dependent mutation rates to predict long-term evolutionary patterns at synonymous sites. We also show that de novo mutations from independent MA experiments display similar patterns of single nucleotide mutation and well match the patterns of mutation found in natural populations.
Newly-born pulsars as sources of ultrahigh energy cosmic rays

Newly born pulsars offer favorable sites for the injection of heavy nuclei, and for their further acceleration to ultrahigh energies. Once accelerated in the pulsar wind, nuclei have to escape from the surrounding supernova envelope. We examine this escape analytically and numerically and discuss the pulsar source scenario in light of the latest ultrahigh energy cosmic ray (UHECR) data. Our calculations show that, at early times, when protons can be accelerated to energies E > 10^(20) eV, the young supernova shell tends to prevent their escape. In contrast, because of their higher charge, iron-peaked nuclei are still accelerated to the highest observed energies at later times, when the envelope has become thin enough to allow their escape. Ultrahigh energy iron nuclei escape newly born pulsars with millisecond periods and dipole magnetic fields of ~10^(12)-10^(13) G, embedded in core-collapse supernovae. Due to the production of secondary nucleons, the envelope crossing leads to a transition of composition from light to heavy elements at a few EeV, as observed by the Auger Observatory. The escape also results in a softer spectral slope than that initially injected via unipolar induction, which allows for a good fit to the observed UHECR spectrum. We conclude that the acceleration of iron-peaked elements in a reasonably small fraction (≾ 0.01%) of extragalactic rotation-powered young pulsars would reproduce satisfactorily the current UHECR data. Possible signatures of this scenario are also discussed.
Feature-coding transitions to conjunction-coding with progression through human visual cortex.

We use a novel analysis of neuroimaging data to assess representations throughout visual cortex, revealing a transition from feature-coding to conjunction-coding along both ventral and dorsal pathw...
Multiplane and Spectrally-Resolved Single Molecule Localization Microscopy with Industrial Grade CMOS cameras

This work explores the use of industrial grade CMOS cameras for single molecule localization microscopy (SMLM). We show that industrial grade CMOS cameras approach the performance of scientific grade CMOS cameras at a fraction of the cost. This makes it more economically feasible to construct high-performance imaging systems with multiple cameras that are capable of a diversity of applications. In particular we demonstrate the use of industrial CMOS cameras for biplane, multiplane and spectrally resolved SMLM. We also provide open-source software for simultaneous control of multiple CMOS cameras and for the reduction of the movies that are acquired to super-resolution images.
Flux growth and magnetic properties of rare earth cobalt germanide, RE6Co5Ge1+xAl3−x (RE=Pr, Nd; x≈0.8)

Abstract The intermetallic compounds RE 6 Co 5 Ge 1+x Al 3−x (RE=Pr , Nd) were synthesized from the reaction of germanium and aluminum in RE/Co eutectic flux. These phases crystallize with the Nd 6 Co 5 Ge 2.2 structure type in hexagonal space group P -6 m 2 ( a =9.203(2)A, c =4.202(1) A, R 1 =0.0109 for Pr 6 Co 5 Ge 1.80 Al 2.20 ; and a =9.170(3) A, c =4.195(1) A, R 1 =0.0129 for Nd 6 Co 5 Ge 1.74 Al 2.26 ). The structure features chains of face-sharing Ge@RE 9 clusters intersecting hexagonal cobalt nets linked by aluminum atoms. Magnetic susceptibility measurements indicate that both phases exhibit ferromagnetic ordering of the cobalt layers with T C in the range of 130–140 K. The magnetic moments of the rare earth ions order at lower temperature (30–40 K). Magnetic measurements on oriented crystals of Nd 6 Co 5 Ge 1.74 Al 2.26 show a strong preference of the moments to order along the c -axis.
Acid-promoted olefination of ketones by an iron(III) porphyrin complex

The acid-promoted olefination of unactivated ketones with diazo reagents in the presence of triphenylphosphine can be catalyzed by the commercially available iron(III) porphyrin complex Fe(TPP)Cl. The reactions were effectively carried out under mild conditions in a one-pot fashion with the use of a stoichiometric diazo reagents and substoichiometric benzoic acid. Examples include aromatic, aliphatic, cyclic, and unsaturated ketones with ethyl diazoacetate or tert-butyl diazoacetate.
Rearrangement of Alkynyl Sulfoxides Catalyzed by Gold(I) Complexes

A series of gold(I)-catalyzed rearrangement reactions of alkynyl sulfoxides are reported. Homopropargylsulfoxides are rearranged to benzothiepinones or benzothiopines, while α-thioenones are formed in the reaction of propargylsulfoxides. The proposed mechanism proceeds via an α-carbonyl gold−carbenoid intermediate formed through gold-promoted oxygen atom transfer from the sulfoxide to the alkyne.
First Rb silicotitanate phase and its K-structural analogue: New members of the SNL-A family (Cc-A2TiSi6O15; A = K, Rb, Cs)

Alkali silicotitanate ternary phases have been studied for a wide variety of applications including catalysis, selective ion exchange, and ceramic nuclear waste form materials. We report here the synthesis and structural characterization of Rb2TiSi6O15 and K2TiSi6O15, structural analogues to SNL-A (Cc-Cs2TiSi6O15). The Rb analogue is the first reported ternary oxide, the rubidium silicotitanate phase. Both the Rb and the K analogues were synthesized nearly pure by hydrothermal treatment of oxide precursor mixtures seeded with SNL-A and could not be synthesized without the addition of the seed. Rietveld refinement gave good structural models in the Cc space group with unit cell parameters: Rb2TiSi6O15, V = 1357.9 A3, a = 12.736(2) A, b = 7.3392(3) A, c = 15.061(3) A, β = 105.29(2)° and K2TiSi6O15, V = 1318.5 A3, a = 12.570(2) A, b = 7.2534(3) A, c = 15.082(3) A, β = 106.49(3)°. The two isostructural phases were also characterized by thermogravimetry and 29Si NMR. Unit cell parameters, melting temperatures...
Head and Tail Speeds of Mean Curvature Flow with Forcing

In this paper, we investigate the large time behavior of interfaces moving with motion law $$V = -\,\kappa + g(x)$$, where g is positive, Lipschitz and $${\mathbb {Z}}^n$$-periodic. We show that the behavior of the interface can be characterized by its head and tail speeds $${\bar{s}}$$ and $$\underline{s}$$, which only depend on its overall direction of propagation $$\nu $$. We discuss the large time behavior of the moving interface in terms of $${\bar{s}}$$ and $$\underline{s}$$, which is shown to vary continuously in $$\nu $$. In the laminar setting we show that when $${\bar{s}}>\underline{s}$$ there exists an unbounded stationary solution as well as localized traveling waves with different speeds.
Lyapunov exponents of free operators

Abstract Lyapunov exponents of a dynamical system are a useful tool to gauge the stability and complexity of the system. This paper offers a definition of Lyapunov exponents for a sequence of free linear operators. The definition is based on the concept of the extended Fuglede–Kadison determinant. We establish the existence of Lyapunov exponents, derive formulas for their calculation, and show that Lyapunov exponents of free variables are additive with respect to operator product. We illustrate these results using an example of free operators whose singular values are distributed by the Marchenko–Pastur law, and relate this example to C.M. Newman's “triangle” law for the distribution of Lyapunov exponents of large random matrices with independent Gaussian entries. As an interesting by-product of our results, we derive a relation between the extended Fuglede–Kadison determinant and Voiculescu's S -transform.
Shortcut-Stacked Sentence Encoders for Multi-Domain Inference

We present a simple sequential sentence encoder for multi-domain natural language inference. Our encoder is based on stacked bidirectional LSTM-RNNs with shortcut connections and fine-tuning of word embeddings. The overall supervised model uses the above encoder to encode two input sentences into two vectors, and then uses a classifier over the vector combination to label the relationship between these two sentences as that of entailment, contradiction, or neural. Our Shortcut-Stacked sentence encoders achieve strong improvements over existing encoders on matched and mismatched multi-domain natural language inference (top single-model result in the EMNLP RepEval 2017 Shared Task (Nangia et al., 2017)). Moreover, they achieve the new state-of-the-art encoding result on the original SNLI dataset (Bowman et al., 2015).
Spectral Approximation for Quasiperiodic Jacobi Operators

Quasiperiodic Jacobi operators arise as mathematical models of quasicrystals and in more general studies of structures exhibiting aperiodic order. The spectra of these self-adjoint operators can be quite exotic, such as Cantor sets, and their fine properties yield insight into the associated quantum dynamics, that is, the one-parameter unitary group that solves the time-dependent Schrodinger equation. Quasiperiodic operators can be approximated by periodic ones, the spectra of which can be computed via two finite dimensional eigenvalue problems. Since long periods are necessary for detailed approximations, both computational efficiency and numerical accuracy become a concern. We describe a simple method for numerically computing the spectrum of a period-K Jacobi operator in O(K 2) operations, then use the algorithm to investigate the spectra of Schrodinger operators with Fibonacci, period doubling, and Thue–Morse potentials.
Demixing sines and spikes: Robust spectral super-resolution in the presence of outliers

We consider the problem of super-resolving the line spectrum of a multisinusoidal signal from a finite number of samples, some of which may be completely corrupted. Measurements of this form can be modeled as an additive mixture of a sinusoidal and a sparse component. We propose to demix the two components and super-resolve the spectrum of the multisinusoidal signal by solving a convex program. Our main theoretical result is that-- up to logarithmic factors-- this approach is guaranteed to be successful with high probability for a number of spectral lines that is linear in the number of measurements, even if a constant fraction of the data are outliers. The result holds under the assumption that the phases of the sinusoidal and sparse components are random and the line spectrum satisfies a minimum-separation condition. We show that the method can be implemented via semidefinite programming and explain how to adapt it in the presence of dense perturbations, as well as exploring its connection to atomic-norm denoising. In addition, we propose a fast greedy demixing method which provides good empirical results when coupled with a local nonconvex-optimization step.
Hankel Operators on the Bergman spaces of Reinhardt Domains and Foliations of Analytic Disks

Let $$\Omega \subset \mathbb {C}^2$$ be a bounded pseudoconvex complete Reinhardt domain with a smooth boundary. We study the behavior of analytic structure in the boundary of $$\Omega $$ and obtain a compactness result for Hankel operators on the Bergman space of $$\Omega $$.
Targeted Kernel Networks: Faster Convolutions with Attentive Regularization.

We propose Attentive Regularization (AR), a method to constrain the activation maps of kernels in Convolutional Neural Networks (CNNs) to specific regions of interest (ROIs). Each kernel learns a location of specialization along with its weights through standard backpropagation. A differentiable attention mechanism requiring no additional supervision is used to optimize the ROIs. Traditional CNNs of different types and structures can be modified with this idea into equivalent Targeted Kernel Networks (TKNs), while keeping the network size nearly identical. By restricting kernel ROIs, we reduce the number of sliding convolutional operations performed throughout the network in its forward pass, speeding up both training and inference. We evaluate our proposed architecture on both synthetic and natural tasks across multiple domains. TKNs obtain significant improvements over baselines, requiring less computation (around an order of magnitude) while achieving superior performance.