cssi/SciSciGPT-SciSciNet huggingface dataset:
A new sesquiterpene from Nicotiana umbratica Burbidge

Abstract A new sesquiterpene, (1 S ,2 S ,6 R ,8 R )-1-isopropyl-5-(hydroxymethyl)-8-methyltricyclo[4.4.0.0 2,R ]dec-4-ene ( 1 ), was isolated and identified from the leaf surface lipids of Nicotiana umbratica Burbidge. The structure of compound 1 , including the absolute stereochemistry, was established on the basis of its spectral data and X-ray diffraction analysis of 15- p -bromobenzoate ( 1a ).
Hetero Diels-Alder reactions of 1-amino-3-siloxy-1,3-butadienes under strictly thermal conditions.

The hetero Diels−Alder reaction of 1-amino-3-siloxy-1,3-butadiene (1a) with a range of unactivated aldehydes proceeds readily under remarkably mild conditions: at room temperature and in the absence of Lewis acid catalysts. The cycloadducts are formed in good yields and can be converted directly to the corresponding dihydro-4-pyrones using acetyl chloride. Ketones and imines are also reactive in hetero Diels−Alder reactions with this diene.
Stereoselective Synthesis of 1,2-Disubstituted β-Amino Alcohols by Nucleophilic Addition to N-tert-Butanesulfinyl α-Alkoxyaldimines

N-tert-Butanesulfinyl α-alkoxyaldimines are readily prepared from protected (S)-lactals without epimerization at the α-stereocenter. Addition of ethyl and phenyl Grignard reagents, as well as the titanium enolate of methyl acetate, to the N-tert-butanesulfinyl aldimines provides 1,2-disubstituted β-amino alcohols in good yields (73−98%) and with high diastereoselectivities. Either syn- or anti-amino alcohol products can be obtained by the appropriate choice of alcohol protecting groups and/or reaction conditions. Finally, deprotection of the addition products provides straightforward access to either syn- or anti-1,2-amino alcohols.
Toward an arsenic analogue of Hittorf's phosphorus: Mixed pnicogen chains in Cu2P1.8As1.2I2

The new compound Cu2P1.8As1.2I2, with neutral, mixed pnicogen chains, has been synthesized from a stoichiometric combination of CuI, P, and As heated in vacuo at 550 °C. Cu2P1.8As1.2I2 represents s...
Enantioselective synthesis of dihydro-1H-benzindoles

The first examples of dihydro-1H-benzindoles by enantioselective γ-lactamization reaction of naphthyl sulfilimines with trichloroacetyl chloride in the presence of ZnCu as catalyst (≥98:2 er and 65–80% yields) are described. Products are obtained by [3,3]-sigmatropic rearrangement of the azasulfonium enolate or followed by a second allylic rearrangement that transfers chirality. The absolute stereochemistry was confirmed by X-ray crystallography, which provides support for the mechanisms proposed.
Crystal structure and magnetism of Gd2MgGe2

Abstract The title compound, Gd2MgGe2, crystallizes in a ternary variant of the tetragonal U3Si2 structure type with unit cell parameters of a=7.291(1) and c=4.2826(8) A, space group P4/mbm, Z=2. Temperature (4.3–300 K) and magnetic field (0–50 kOe) dependencies of the dc magnetization, along with temperature dependence of the ac magnetic susceptibility (25 Oe, 125 Hz) of Gd2MgGe2 are presented. The behavior of both the dc magnetization and ac magnetic susceptibility above ca. 150 K indicates a disordered magnetic state for Gd atoms while below ca. 150 K, it shows the existence of antiferromagnetic order. Tight-binding electronic structure (TB–LMTO–ASA) calculations including spin-polarization are utilized to discuss the chemical bonding and provide insights for the magnetic ordering process in this compound.
Photocatalytic initiation of thiol–ene reactions: synthesis of thiomorpholin-3-ones

Abstract A mild, redox neutral photocatalytic method for alkene hydrothiolation is reported. Utilizing visible-light activation, catalytic radical initiation is achieved with the transition metal complex Ru(bpy)3Cl2, enabling rapid access to a diverse set of thiol–ene coupled products in excellent yield. On the basis of a strong observed background reaction in some cases, we have developed a solvent-free, Lewis acid-promoted tandem amidation–hydrothiolation sequence, providing thiomorpholin-3-ones in a one-pot operation from commercially available materials.
Synthesis of methyl 3‐amino‐4‐aryl(or methyl)sulfonyl‐2‐thiophenecarboxylates from 3‐alkoxy‐2‐aryl(or methyl)‐sulfonylacrylonitriles

The synthesis of a series of methyl 3-amino-4-aryl(or methyl)sulfonylthiophene-2-carboxylates by reaction of 3-alkoxy-2-aryI(or methyl)sulfonylacrylonitriles with methyl thioglycolate in the presence of triethylamine is described. Hydrolysis/decarboxylation of the ester at the 2-position and acylation of the resulting amine represents a convenient route to 4-arylsulfonyl-3-carboxamidothiophenes. Attempted acylation of a title aminothiophene under standard conditions was unsuccessful.
Ferrocenylmethylphosphines as ligands for room temperature Ni(0)-catalyzed Suzuki–Miyaura cross-coupling reactions of aryl arenesulfonates and aryl chlorides

Abstract Readily available ferrocenylmethylphosphine was found as an efficient ligand for room temperature Ni(0)-catalyzed Suzuki–Miyaura cross-couplings of aryl arenesulfonates. Ferrocenylmethylphosphine and its polymeric form were also found as useful ligands for Ni(0)-catalyzed Suzuki–Miyaura couplings of deactivated aryl chlorides.
Enantioselective synthesis of 2-substituted 2-phenylethylamines by lithiation-substitution sequences: synthetic development and mechanistic pathway.

The lithiation and asymmetric substitution of N-(2-phenylethyl)isobutyramide (2) with selected electrophiles, under the influence of (−)-sparteine, provides benzylically substituted products in 58−90% yields with enantiomeric ratios (ers) from 72:28 to 91:9. Syntheses of enantioenriched dihydroisoquinolines (S)-18 and (S)-19 and a tetrahydroisoquinoline (4S)-20 provide examples of synthetic applications. Mechanistic investigations suggest the enantiodetermining step at −78 °C is a dynamic thermodynamic resolution.
Increasing Rates of Diagnosis, Substantial Co-Occurrence, and Variable Treatment Patterns of Eosinophilic Gastritis, Gastroenteritis, and Colitis Based on 10-Year Data Across a Multicenter Consortium.

OBJECTIVES:The literature related to eosinophilic gastritis (EG), gastroenteritis (EGE), and colitis (EC) is limited. We aimed to characterize rates of diagnosis, clinical features, and initial treatments for patients with EG, EGE, and EC.METHODS:In this retrospective study, data were collected from
A mechanistically designed mono-cinchona alkaloid is an excellent catalyst for the enantioselective dihydroxylation of olefins

Abstract On the basis of ideas recently advanced regarding the origin of enantioselectivity in the OsO4-promoted dihydroxylation of olefins catalyzed by bis-cinchona alkaloid derivatives such as 1, specifically strong evidence for reaction via transition state assembly 2, the mono-quinidine derivative 3 was selected as a promising catalytic ligand. The experimental observation of high enantioselectivity promoted by 3 provides additional evidence in favor of transition-state 2.
Storyboarding of Recipes: Grounded Contextual Generation

Information need of humans is essentially multimodal in nature, enabling maximum exploitation of situated context. We introduce a dataset for sequential procedural (how-to) text generation from images in cooking domain. The dataset consists of 16,441 cooking recipes with 160,479 photos associated with different steps. We setup a baseline motivated by the best performing model in terms of human evaluation for the Visual Story Telling (ViST) task. In addition, we introduce two models to incorporate high level structure learnt by a Finite State Machine (FSM) in neural sequential generation process by: (1) Scaffolding Structure in Decoder (SSiD) (2) Scaffolding Structure in Loss (SSiL). Our best performing model (SSiL) achieves a METEOR score of 0.31, which is an improvement of 0.6 over the baseline model. We also conducted human evaluation of the generated grounded recipes, which reveal that 61% found that our proposed (SSiL) model is better than the baseline model in terms of overall recipes. We also discuss analysis of the output highlighting key important NLP issues for prospective directions.
Ti2Nb6O12, a Novel Niobium Oxide Cluster Compound with “Chevrel Phase” Intercluster Connectivity Type

The niobium oxide cluster compound Ti2Nb6O12 was synthesized from NbO, NbO2, and TiO2 in the presence of NaF melt at 950 °C. It crystallizes in an original structure type based on octahedral cluste...
Stereochemical control in intramolecular Diels-Alder reactions with carbene complexes as ester synthons

An evaluation of the intramolecular Diels-Alder reactions of Fischer carbene complexes was madefor complexes which have an all-carbon tether between the diene and dienophile. Specifically, both the cis- and trans-isomerq of the deca-2,7,9-trienyl carbene complexes (26-cis, 20-trans) and the undeca-2,8,10-trienyl carbene complexes (27-cis, 25-trans) were prepared and the rates and stereoselectivities of their intramolecular Diels-Alder reactions were in each case compared with those of the known reactions of their corresponding methyl esters
Radical additions to β,β-difluoroacrylates

Abstract Tetrahydrofuran, 1,3-dioxolane, hexanal, and benzaldehyde react readily with β,β-difluoroacrylates under free radical conditions to furnish adducts in moderate to high yield.
Clustering effects on firm exporting with productivity‐enhancing R&D in China

This paper examines the effects of regional clustering on the linkages among R&D, exporting and productivity of Chinese firms. A structural framework is employed using a set of recursive equations that is capable of correcting for most estimation issues related to selection and endogeneity. The main findings reveal that regional clustering brings about relatively trivial direct benefits to exporters after taking into account important sources of firm heterogeneity. Rather, the main benefits of clustering on exporting appear to arise indirectly through investments in innovation and productivity. The main implication of the findings suggests that a better endowed geographical area improves international competitiveness mainly by enhancing the super‐additive effects of investments in technology on productivity, which, in turn, enhances exporting performance.
BiOClO4-mediated deprotection of silyl ethers

Abstract TES- and TBS-protected alcohols undergo deprotection in good to excellent yield upon heating with 1 equiv of BiOClO 4 - x H 2 O in CH 2 Cl 2 . TBDPS- and TIPS-protected 2° alcohols are more resistant to deprotection. The use of this method in selective desilylation is, however, limited to the deprotection of alkyl silyl ethers in the presence of TBDPS-protected phenols.
Preparation and reactions of 3‐oxa‐ and 4‐oxa‐5‐hexenyllithiums

Low-temperature lithium–iodine exchange between tert-butyllithium and the appropriate iodide has been used to generate 3-oxa-5-hexenyllithium and a variety of 4-oxa-5-hexenyllithiums. The 3-oxa system is inherently unstable and fragments via facile β-elimination to give the anion of allyl alcohol and ethylene. The 4-oxa-5-hexenyllithiums, in contrast, are stable at low temperatures but undergo novel isomerization upon warming to deliver the lithium salt of a 4-alken-1-ol in the formal equivalent of an unprecedented [1,4]-Wittig rearrangement. The rearrangement is most likely mediated by 5-exo-trig ring closure of the 4-oxa-5-hexenyllithium to a (2-tetrahydrofuranyl)methyllithium followed by rapid opening to the alkoxide.
Quaternary Intermetallics Grown from Molten Aluminum: The Homologous Series Th2(AuxSi1-x)[AuAl2]nSi2 (n = 1, 2, 4)

An appropriate combination of Th or ThO2 with Au and Si in liquid aluminum has resulted in the formation of three new quaternary intermetallic compounds. All three materials grow as large platelike crystals and have structure types that define a new homologous series. Th2AuAl2Si3 is tetragonal, I41/amd, with unit cell parameters a = 4.2119(4) A and c = 36.165(5) A. Th2Au3Al4Si2 and Th2Au5Al8Si2 both crystallize in the orthorhombic space group Cmmm, with cell parameters a = 4.266(1) A, b = 23.574(8) A, and c = 4.249(1) A and a = 4.2612(8) A, b = 35.661(7) A, and c = 4.2487(8) A, respectively. The Th2(AuxSi1-x)[AuAl2]nSi2 structures feature planes of parallel infinite zigzag silicon chains alternating with slabs of antifluorite type AuAl2. The AuAl2 slabs increase in thickness going from Th2AuAl2Si3 (n = 1) to Th2Au5Al8Si2 (n = 4). All three materials show temperature independent Pauli paramagnetism and metallic conductivity. Band structure calculations were carried out on each compound using density functi...
Titanium-Mediated Spirocyclization Reactions of 4-Alkylpyridines

Pyridines substituted at the 4-position with alkyl tethers containing β-dicarbonyl moieties were converted to spirocyclic 4,4-disubstituted dihydropyridines. Optimal conditions for these transformations involved N-acylation of the pyridine substrate with a chloroformate electrophile in the presence of Ti(OiPr)4. Cyclization products could be easily converted into spiro-piperidine derivatives or elaborated into more complex heterocyclic frameworks via Au-catalyzed cycloisomerization.
Novel Plasmodium falciparum metabolic network reconstruction identifies shifts associated with clinical antimalarial resistance

Malaria remains a major public health burden and resistance has emerged to every antimalarial on the market, including the frontline drug, artemisinin. Our limited understanding of Plasmodium biology hinders the elucidation of resistance mechanisms. In this regard, systems biology approaches can facilitate the integration of existing experimental knowledge and further understanding of these mechanisms. Here, we developed a novel genome-scale metabolic network reconstruction, iPfal17, of the asexual blood-stage P. falciparum parasite to expand our understanding of metabolic changes that support resistance. We identified 11 metabolic tasks to evaluate iPfal17 performance. Flux balance analysis and simulation of gene knockouts and enzyme inhibition predict candidate drug targets unique to resistant parasites. Moreover, integration of clinical parasite transcriptomes into the iPfal17 reconstruction reveals patterns associated with antimalarial resistance. These results predict that artemisinin sensitive and resistant parasites differentially utilize scavenging and biosynthetic pathways for multiple essential metabolites, including folate and polyamines. Our findings are consistent with experimental literature, while generating novel hypotheses about artemisinin resistance and parasite biology. We detect evidence that resistant parasites maintain greater metabolic flexibility, perhaps representing an incomplete transition to the metabolic state most appropriate for nutrient-rich blood. Using this systems biology approach, we identify metabolic shifts that arise with or in support of the resistant phenotype. This perspective allows us to more productively analyze and interpret clinical expression data for the identification of candidate drug targets for the treatment of resistant parasites.
Enantioselective reduction of β-keto esters

Abstract Highly enantioselective reduction of β-keto esters with BINAP-Ru catalyst can be effected at 50 psig H2 and 80°, using a Parr shaker. A simplified preparation of the BINAP-Ru catalyst is reported. Highly enantioselective reduction of β-keto esters with BINAP-Ru catalyst can be effected at 50 psig H2 and 80°, using a Parr shaker. A simplified preparation of the BINAP·Ru catalyst is reported.
Fast intensity adaptation enhances the encoding of sound in Drosophila

To faithfully encode complex stimuli, sensory neurons should correct, via adaptation, for stimulus properties that corrupt pattern recognition. Here we investigate sound intensity adaptation in the Drosophila auditory system, which is largely devoted to processing courtship song. Mechanosensory neurons (JONs) in the antenna are sensitive not only to sound-induced antennal vibrations, but also to wind or gravity, which affect the antenna's mean position. Song pattern recognition, therefore, requires adaptation to antennal position (stimulus mean) in addition to sound intensity (stimulus variance). We discover fast variance adaptation in Drosophila JONs, which corrects for background noise over the behaviorally relevant intensity range. We determine where mean and variance adaptation arises and how they interact. A computational model explains our results using a sequence of subtractive and divisive adaptation modules, interleaved by rectification. These results lay the foundation for identifying the molecular and biophysical implementation of adaptation to the statistics of natural sensory stimuli.
A DNA-Binding Protein Tunes Septum Placement during Bacillus subtilis Sporulation.

ABSTRACT Bacillus subtilis is a bacterium capable of differentiating into a spore form more resistant to environmental stress. Early in sporulation, each cell possesses two copies of a circular chromosome. A polar FtsZ ring (Z ring) directs septation over one of the chromosomes, generating two cell compartments. The smaller “forespore” compartment initially contains only 25 to 30% of one chromosome, and this transient genetic asymmetry is required for differentiation. Timely assembly of polar Z rings and precise capture of the chromosome in the forespore both require the DNA-binding protein RefZ. To mediate its role in chromosome capture, RefZ must bind to specific DNA motifs (RBMs) that localize near the poles at the time of septation. Cells artificially induced to express RefZ during vegetative growth cannot assemble Z rings, an effect that also requires DNA binding. We hypothesized that RefZ-RBM complexes mediate precise chromosome capture by modulating FtsZ function. To investigate, we isolated 10 RefZ loss-of-function (rLOF) variants unable to inhibit cell division yet still capable of binding RBMs. Sporulating cells expressing the rLOF variants in place of wild-type RefZ phenocopied a ΔrefZ mutant, suggesting that RefZ acts through an FtsZ-dependent mechanism. The crystal structure of RefZ was solved, and wild-type RefZ and the rLOF variants were further characterized. Our data suggest that RefZ’s oligomerization state and specificity for the RBMs are critical determinants influencing RefZ’s ability to affect FtsZ dynamics. We propose that RBM-bound RefZ complexes function as a developmentally regulated nucleoid occlusion system for fine-tuning the position of the septum relative to the chromosome during sporulation. IMPORTANCE The bacterial nucleoid forms a large, highly organized structure. Thus, in addition to storing the genetic code, the nucleoid harbors positional information that can be leveraged by DNA-binding proteins to spatially constrain cellular activities. During B. subtilis sporulation, the nucleoid undergoes reorganization, and the cell division protein FtsZ assembles polarly to direct septation over one chromosome. The TetR family protein RefZ binds DNA motifs (RBMs) localized near the poles at the time of division and is required for both timely FtsZ assembly and precise capture of DNA in the future spore compartment. Our data suggest that RefZ exploits nucleoid organization by associating with polarly localized RBMs to modulate the positioning of FtsZ relative to the chromosome during sporulation.
Diversity of Mycobacterium tuberculosis across Evolutionary Scales

Tuberculosis (TB) is a global public health emergency. Increasingly drug resistant strains of Mycobacterium tuberculosis (M.tb) continue to emerge and spread, highlighting adaptability of this pathogen. Most studies of M.tb evolution have relied on ‘between-host’ samples, in which each person with TB is represented by a single M.tb isolate. However, individuals with TB commonly harbor populations of M.tb numbering in the billions. Here, we use analyses of M.tb genomic data from within and between hosts to gain insight into influences shaping genetic diversity of this pathogen. We find that the amount of M.tb genetic diversity harbored by individuals with TB can vary dramatically, likely as a function of disease severity. Surprisingly, we did not find an appreciable impact of TB treatment on M.tb diversity. In examining genomic data from M.tb samples within and between hosts with TB, we find that genes involved in the regulation, synthesis, and transportation of immunomodulatory cell envelope lipids appear repeatedly in the extremes of various statistical measures of diversity. Many of these genes have been identified as possible targets of selection in other studies employing different methods and data sets. Taken together, these observations suggest that M.tb cell envelope lipids are targets of selection within hosts. Many of these lipids are specific to pathogenic mycobacteria and, in some cases, human-pathogenic mycobacteria. We speculate that rapid adaptation of cell envelope lipids is facilitated by functional redundancy, flexibility in their metabolism, and their roles mediating interactions with the host.
Variously substituted glycals are readily prepared from glycosyl bromides using (Cp2TiCl)2

Abstract Glycosyl halides, variously substituted with ether, acetal, or ester protecting groups, were converted to the corresponding glycals in high yield by reaction with (C p2 TiCl) 2 . A glycosyl chloride was less reactive than the analogous bromide.
Approaches to stable cyclopropenyl anions: Tris-1,2,3-p-nitrophenylcyclopropene

Abstract Tris-1,2,3-p-nitrophenylcyclopropene has been synthesized from the tosylhydrazone of an enone, and examined as a precursor of the corresponding cyclopropenyl anion. A precursor of the related trimethylsilylcyclopropene has also been prepared by a series of palladium-catalyzed reactions.
Synthesis of α-Necrodol: Unexpected Formation of a Cyclopropene

Significant 1,3-induction in intramolecular alkylidene C−H insertion is reported. Thus, exposure of ketone I to the lithium salt of (trimethylsilyl)diazomethane provides a 2.4:1.0 ratio of IIa and IIIa, which are deprotected to α-necrodol IIb and the epimeric IIIb. The 1,3-insertion product cyclopropene IV was also formed.
Convergence of first-order methods via the convex conjugate

Abstract This paper gives a unified and succinct approach to the O ( 1 ∕ k ) , O ( 1 ∕ k ) , and O ( 1 ∕ k 2 ) convergence rates of the subgradient, gradient, and accelerated gradient methods for unconstrained convex minimization. In the three cases the proof of convergence follows from a generic bound defined by the convex conjugate of the objective function.
Gorenstein injective envelopes and covers over two sided noetherian rings

We prove that the class of Gorenstein injective modules is both enveloping and covering over a two sided noetherian ring such that the character modules of Gorenstein injective modules are Gorenste...
Linearized binary regression

Probit regression was first proposed by Bliss in 1934 to study mortality rates of insects. Since then, an extensive body of work has analyzed and used probit or related binary regression methods (such as logistic regression) in numerous applications and fields. This paper provides a fresh angle to such well-established binary regression methods. Concretely, we demonstrate that linearizing the probit model in combination with linear estimators performs on par with state-of-the-art nonlinear regression methods, such as posterior mean or maximum aposteriori estimation, for a broad range of real-world regression problems. We derive exact, closed-form, and nonasymptotic expressions for the mean-squared error of our linearized estimators, which clearly separates them from nonlinear regression methods that are typically difficult to analyze. We showcase the efficacy of our methods and results for a number of synthetic and real-world datasets, which demonstrates that linearized binary regression finds potential use in a variety of inference, estimation, signal processing, and machine learning applications that deal with binary-valued observations or measurements.
Coupled motion of asymmetrical tilt grain boundaries: Molecular dynamics and phase field crystal simulations

Abstract Previous simulation and experimental studies have shown that some grain boundaries (GBs) can couple to applied shear stresses and be moved by them, producing shear deformation of the lattice traversed by their motion. While this coupling effect has been well confirmed for symmetrical tilt GBs, little is known about the coupling ability of asymmetrical boundaries. In this work we apply a combination of molecular dynamics and phase field crystal simulations to investigate stress-driven motion of asymmetrical GBs between cubic crystals over the entire range of inclination angles. Our main findings are that the coupling effect exists for most of the asymmetrical GBs and that the coupling factor exhibits a non-trivial dependence on both the misorientation and inclination angles. This dependence is characterized by a discontinuous change of sign of the coupling factor, which reflects a transition between two different coupling modes over a narrow range of angles. Importantly, the magnitude of the coupling factor becomes large or divergent within this transition region, thereby giving rise to a sliding-like behavior. Our results are interpreted in terms of a diagram presenting the domains of existence of the two coupling modes and the transition region between them in the plane of misorientation and inclination angles. The simulations reveal some of the dislocation mechanisms responsible for the motion of asymmetrical tilt GBs. The results of this study compare favorably with existing experimental measurements and provide a theoretical ground for the design of future experiments.
Natural realizations of sparsity matroids

A hypergraph G with n vertices and m hyperedges with d endpoints each is ( k , l )-sparse if for all sub-hypergraphs G' on n' vertices and m' edges, m' ≤ kn' − l . For integers k and l satisfying 0 ≤ l ≤ dk − 1, this is known to be a linearly representable matroidal family. Motivated by problems in rigidity theory, we give a new linear representation theorem for the ( k , l )-sparse hypergraphs that is natural ; i.e., the representing matrix captures the vertex-edge incidence structure of the underlying hypergraph G .
Compressive sensing of analog signals using Discrete Prolate Spheroidal Sequences

Abstract Compressive sensing (CS) has recently emerged as a framework for efficiently capturing signals that are sparse or compressible in an appropriate basis. While often motivated as an alternative to Nyquist-rate sampling, there remains a gap between the discrete, finite-dimensional CS framework and the problem of acquiring a continuous-time signal. In this paper, we attempt to bridge this gap by exploiting the Discrete Prolate Spheroidal Sequences (DPSSʼs), a collection of functions that trace back to the seminal work by Slepian, Landau, and Pollack on the effects of time-limiting and bandlimiting operations. DPSSʼs form a highly efficient basis for sampled bandlimited functions; by modulating and merging DPSS bases, we obtain a dictionary that offers high-quality sparse approximations for most sampled multiband signals. This multiband modulated DPSS dictionary can be readily incorporated into the CS framework. We provide theoretical guarantees and practical insight into the use of this dictionary for recovery of sampled multiband signals from compressive measurements.
Frequency analysis and resonant operation for efficient capacitive deionization.

Abstract Capacitive deionization (CDI) performance metrics can vary widely with operating methods. Conventional CDI operating methods such as constant current and constant voltage show advantages in either energy or salt removal performance, but not both. We here develop a theory around and experimentally demonstrate a new operation for CDI that uses sinusoidal forcing voltage (or sinusoidal current). We use a dynamic system modeling approach, and quantify the frequency response (amplitude and phase) of CDI effluent concentration. Using a wide range of operating conditions, we demonstrate that CDI can be modeled as a linear time invariant system. We validate this model with experiments, and show that a sinusoid voltage operation can simultaneously achieve high salt removal and strong energy performance, thus very likely making it superior to other conventional operating methods. Based on the underlying coupled phenomena of electrical charge (and ionic) transfer with bulk advection in CDI, we derive and validate experimentally the concept of using sinusoidal voltage forcing functions to achieve resonance-type operation for CDI. Despite the complexities of the system, we find a simple relation for the resonant time scale: the resonant time period (frequency) is proportional (inversely proportional) to the geometric mean of the flow residence time and the electrical (RC) charging time. Operation at resonance implies the optimal balance between absolute amount of salt removed (in moles) and dilution (depending on the feed volume processed), thus resulting in the maximum average concentration reduction for the desalinated water. We further develop our model to generalize the resonant time-scale operation, and provide responses for square and triangular voltage waveforms as two examples. To this end, we develop a general tool that uses Fourier analysis to construct CDI effluent dynamics for arbitrary input waveforms. Using this tool, we show that most of the salt removal (∼95%) for square and triangular voltage forcing waveforms is achieved by the fundamental Fourier (sinusoidal) mode. The frequency of higher Fourier modes precludes high flow efficiency for these modes, so these modes consume additional energy for minimal additional salt removed. This deficiency of higher frequency modes further highlights the advantage of DC-offset sinusoidal forcing for CDI operation.
Exact analysis of k-connectivity in secure sensor networks with unreliable links

The Eschenauer-Gligor (EG) random key predistri-bution scheme has been widely recognized as a typical approach to secure communications in wireless sensor networks (WSNs). However, there is a lack of precise probability analysis on the reliable connectivity of WSNs under the EG scheme. To address this, we rigorously derive the asymptotically exact probability of k-connectivity in WSNs employing the EG scheme with unreliable links represented by independent on/off channels, where k-connectivity ensures that the network remains connected despite the failure of any (k−1) sensors or links. Our analytical results are confirmed via numerical experiments, and they provide precise guidelines for the design of secure WSNs that exhibit a desired level of reliability against node and link failures.
AudExpCreator: A GUI-based Matlab tool for designing and creating auditory experiments with the Psychophysics Toolbox

Abstract We present AudExpCreator, a GUI-based Matlab tool for designing and creating auditory experiments. AudExpCreator allows users to generate auditory experiments that run on Matlab’s Psychophysics Toolbox without having to write any code; rather, users simply follow instructions in GUIs to specify desired design parameters. The software comprises five auditory study types, including behavioral studies and integration with EEG and physiological response collection systems. Advanced features permit more complicated experimental designs as well as maintenance and update of previously created experiments. AudExpCreator alleviates programming barriers while providing a free, open-source alternative to commercial experimental design software.
Concentration of the empirical level sets of Tukey’s halfspace depth

Tukey’s halfspace depth has attracted much interest in data analysis, because it is a natural way of measuring the notion of depth relative to a cloud of points or, more generally, to a probability measure. Given an i.i.d. sample, we investigate the concentration of upper level sets of the Tukey depth relative to that sample around their population version. We show that under some mild assumptions on the underlying probability measure, concentration occurs at a parametric rate and we deduce moment inequalities at that same rate. In a computational prospective, we study the concentration of a discretized version of the empirical upper level sets.
Mitigating the Risk of Voltage Collapse Using Statistical Measures From PMU Data

With the continued deployment of synchronized phasor measurement units (PMUs), high sample rate data are rapidly increasing the real time observability of power systems. Prior research has shown that the statistics of these data can provide useful information regarding network stability, but it is not yet known how this statistical information can be actionably used to improve power system stability. To address this issue, this paper presents a method that gauges and improves the voltage stability of a system using the statistics present in PMU data streams. Leveraging an analytical solver to determine a range of “critical” bus voltage variances, the presented methods monitor raw statistical data in an observable load pocket to determine when control actions are needed to mitigate the risk of voltage collapse. A simple reactive power controller is then implemented, which acts dynamically to maintain an acceptable voltage stability margin within the system. Time domain simulations on 3-bus and 39-bus test cases demonstrate that the resulting statistical controller can outperform more conventional feedback control systems by maintaining voltage stability margins while loads simultaneously increase and fluctuate.
A family of Bell transformations

Abstract We introduce a family of sequence transformations, defined via partial Bell polynomials, that may be used for a systematic study of a wide variety of problems in enumerative combinatorics. This family includes some of the transformations listed in the paper by Bernstein & Sloane, now seen as transformations under the umbrella of partial Bell polynomials. Our goal is to describe these transformations from the algebraic and combinatorial points of view. We provide functional equations satisfied by the generating functions, derive inverse relations, and give a convolution formula. While the full range of applications remains unexplored, in this paper we show a glimpse of the versatility of Bell transformations by discussing the enumeration of several combinatorial configurations, including rational Dyck paths, rooted planar maps, and certain classes of permutations.
Controller synthesis with inductive proofs for piecewise linear systems: An SMT-based algorithm

We present a controller synthesis algorithm for reach-avoid problems for piecewise linear discrete-time systems. Our algorithm relies on SMT solvers and in this paper we focus on piecewise constant control strategies. Our algorithm generates feedback control laws together with inductive proofs of unbounded time safety and progress properties with respect to the reach-avoid sets. Under a reasonable robustness assumption, the algorithm is shown to be complete. That is, it either generates a controller of the above type along with a proof of correctness, or it establishes the impossibility of the existence of such controllers. To achieve this, the algorithm iteratively attempts to solve a weakened and strengthened versions of the SMT encoding of the reach-avoid problem. We present preliminary experimental results on applying this algorithm based on a prototype implementation.
Linear–quadratic stochastic two-person nonzero-sum differential games: Open-loop and closed-loop Nash equilibria

Abstract In this paper, we consider a linear–quadratic stochastic two-person nonzero-sum differential game. Open-loop and closed-loop Nash equilibria are introduced. The existence of the former is characterized by the solvability of a system of forward–backward stochastic differential equations, and that of the latter is characterized by the solvability of a system of coupled symmetric Riccati differential equations. Sometimes, open-loop Nash equilibria admit a closed-loop representation, via the solution to a system of non-symmetric Riccati equations, which could be different from the outcome of the closed-loop Nash equilibria in general. However, it is found that for the case of zero-sum differential games, the Riccati equation system for the closed-loop representation of an open-loop saddle point coincides with that for the closed-loop saddle point, which leads to the conclusion that the closed-loop representation of an open-loop saddle point is the outcome of the corresponding closed-loop saddle point as long as both exist. In particular, for linear–quadratic optimal control problem, the closed-loop representation of an open-loop optimal control coincides with the outcome of the corresponding closed-loop optimal strategy, provided both exist.
Counting Trees in Supersymmetric Quantum Mechanics

We study the supersymmetric ground states of the Kronecker model of quiver quantum mechanics. This is the simplest quiver with two gauge groups and bifundamental matter elds, and appears universally in four-dimensional N = 2 systems. The ground state degeneracy may be written as a multi-dimensional contour integral, and the enumeration of poles can be simply phrased as counting bipartite trees. We solve this combinatorics problem, thereby obtaining exact formulas for the degeneracies of an innite class of models. We also develop an algorithm to compute the angular momentum of the ground states, and present explicit expressions for the rened indices of theories where one rank is small.
Connotation Frames: A Data-Driven Investigation

Through a particular choice of a predicate (e.g., "x violated y"), a writer can subtly connote a range of implied sentiments and presupposed facts about the entities x and y: (1) writer's perspective: projecting x as an "antagonist"and y as a "victim", (2) entities' perspective: y probably dislikes x, (3) effect: something bad happened to y, (4) value: y is something valuable, and (5) mental state: y is distressed by the event. We introduce connotation frames as a representation formalism to organize these rich dimensions of connotation using typed relations. First, we investigate the feasibility of obtaining connotative labels through crowdsourcing experiments. We then present models for predicting the connotation frames of verb predicates based on their distributional word representations and the interplay between different types of connotative relations. Empirical results confirm that connotation frames can be induced from various data sources that reflect how people use language and give rise to the connotative meanings. We conclude with analytical results that show the potential use of connotation frames for analyzing subtle biases in online news media.
Enumeration of Commuting Pairs in Lie Algebras over Finite Fields

Feit and Fine derived a generating function for the number of ordered pairs of commuting $$n{\times}n$$ matrices over the finite field $${\mathbb{F}_{q}}$$ . This has been reproved and studied by Bryan and Morrison from the viewpoint of motivic Donaldson-Thomas theory. In this note, we give a new proof of the Feit-Fine result, and generalize it to the Lie algebra of finite unitary groups and to the Lie algebra of odd characteristic finite symplectic groups. We extract some asymptotic information from these generating functions. Finally, we derive generating functions for the number of commuting nilpotent elements for the Lie algebras of the finite general linear and unitary groups, and of odd characteristic symplectic groups.
SignProx: One-bit Proximal Algorithm for Nonconvex Stochastic Optimization

Stochastic gradient descent (SGD) is one of the most widely used optimization methods for parallel and distributed processing of large datasets. One of the key limitations of distributed SGD is the need to regularly communicate the gradients between different computation nodes. To reduce this communication bottleneck, recent work has considered a one-bit variant of SGD, where only the sign of each gradient element is used in optimization. In this paper, we extend this idea by proposing a stochastic variant of the proximal-gradient method that also uses one-bit per update element. We prove the theoretical convergence of the method for non-convex optimization under a set of explicit assumptions. Our results indicate that the compressed method can match the convergence rate of the uncompressed one, making the proposed method potentially appealing for distributed processing of large datasets.
On the numerology of ramification data for power series in characteristic p

Abstract Let k be a perfect field of characteristic p and set K = k ( ( t ) ) . In this paper we study the ramification properties of elements of Aut k ( K ) . By choosing a uniformizer for K we may interpret our theorems in terms of power series over k. The most important tool that we use is the field of norms construction of Fontaine and Wintenberger.
Convex sets associated to C⁎-algebras

Abstract For a separable unital C ⁎ -algebra A and a separable McDuff II 1 -factor M , we show that the space H om w ( A , M ) of weak approximate unitary equivalence classes of unital ⁎-homomorphisms A → M may be considered as a closed, bounded, convex subset of a separable Banach space – a variation on N. Brown's convex structure H om ( N , R U ) . Many separable unital C ⁎ -algebras, including all (separable unital) nuclear C ⁎ -algebras, have the property that for any McDuff II 1 -factor M , H om w ( A , M ) is affinely homeomorphic to the trace space of A . In general H om w ( A , M ) and the trace space of A do not share the same data (several examples are provided). We characterize extreme points of H om w ( A , M ) in many cases, and we give two different conditions – one necessary and the other sufficient – for extremality in general. The universality of C ⁎ ( F ∞ ) is reflected in the fact that for any unital separable A , H om w ( A , M ) may be embedded as a face in H om w ( C ⁎ ( F ∞ ) , M ) . We also extend Brown's construction to apply more generally to H om ( A , M U ) .
Towards understanding the invertibility of convolutional neural networks

Several recent works have empirically observed that Convolutional Neural Nets (CNNs) are (approximately) invertible. To understand this approximate invertibility phenomenon and how to leverage it more effectively, we focus on a theoretical explanation and develop a mathematical model of sparse signal recovery that is consistent with CNNs with random weights. We give an exact connection to a particular model of model-based compressive sensing (and its recovery algorithms) and random-weight CNNs. We show empirically that several learned networks are consistent with our mathematical analysis and then demonstrate that with such a simple theoretical framework, we can obtain reasonable re- construction results on real images. We also discuss gaps between our model assumptions and the CNN trained for classification in practical scenarios.
Count-based exploration with neural density models

Bellemare et al. (2016) introduced the notion of a pseudo-count, derived from a density model, to generalize count-based exploration to non-tabular reinforcement learning. This pseudo-count was used to generate an exploration bonus for a DQN agent and combined with a mixed Monte Carlo update was sufficient to achieve state of the art on the Atari 2600 game Montezuma's Revenge. We consider two questions left open by their work: First, how important is the quality of the density model for exploration? Second, what role does the Monte Carlo update play in exploration? We answer the first question by demonstrating the use of PixelCNN, an advanced neural density model for images, to supply a pseudo-count. In particular, we examine the intrinsic difficulties in adapting Bellemare et al.'s approach when assumptions about the model are violated. The result is a more practical and general algorithm requiring no special apparatus. We combine PixelCNN pseudo-counts with different agent architectures to dramatically improve the state of the art on several hard Atari games. One surprising finding is that the mixed Monte Carlo update is a powerful facilitator of exploration in the sparsest of settings, including Montezuma's Revenge.
MobileNetV2: Inverted Residuals and Linear Bottlenecks

In this paper we describe a new mobile architecture, MobileNetV2, that improves the state of the art performance of mobile models on multiple tasks and benchmarks as well as across a spectrum of different model sizes. We also describe efficient ways of applying these mobile models to object detection in a novel framework we call SSDLite. Additionally, we demonstrate how to build mobile semantic segmentation models through a reduced form of DeepLabv3 which we call Mobile DeepLabv3. is based on an inverted residual structure where the shortcut connections are between the thin bottleneck layers. The intermediate expansion layer uses lightweight depthwise convolutions to filter features as a source of non-linearity. Additionally, we find that it is important to remove non-linearities in the narrow layers in order to maintain representational power. We demonstrate that this improves performance and provide an intuition that led to this design. Finally, our approach allows decoupling of the input/output domains from the expressiveness of the transformation, which provides a convenient framework for further analysis. We measure our performance on ImageNet [1] classification, COCO object detection [2], VOC image segmentation [3]. We evaluate the trade-offs between accuracy, and number of operations measured by multiply-adds (MAdd), as well as actual latency, and the number of parameters.
Distributed communication-aware motion planning for multi-agent systems from STL and SpaTeL specifications

In this paper, we study the control and communication co-design for networked vehicles that coordinate with each other to achieve safe operations. We propose a control-theoretical framework for distributed motion planning for multi-agent such that complex and high-level specifications are satisfied while communication quality is optimized. The desired motion specifications and communication performance are specified as signal temporal logic (STL) and spatial-temporal logic (SpaTeL) formulas, respectively. We encode the formulas as the constraints in mixed integer linear programs (MILP), and upon which control strategies satisfying both STL and SpaTeL specifications are generated locally by employing a distributed model predictive control (MPC) framework. The effectiveness of the proposed framework is validated by simulation.
Bigeometric organization of deep nets

Abstract In this paper, we build an organization of high-dimensional datasets that cannot be cleanly embedded into a low-dimensional representation due to missing entries and a subset of the features being irrelevant to modeling functions of interest. Our algorithm begins by defining coarse neighborhoods of the points and defining an expected empirical function value on these neighborhoods. We then generate new non-linear features with deep net representations tuned to model the approximate function, and re-organize the geometry of the points with respect to the new representation. Finally, the points are locally z-scored to create an intrinsic geometric organization which is independent of the parameters of the deep net, a geometry designed to assure smoothness with respect to the empirical function. We examine this approach on data from the Center for Medicare and Medicaid Services Hospital Quality Initiative, and generate an intrinsic low-dimensional organization of the hospitals that is smooth with respect to an expert driven function of quality.
Optimization on sparse random hypergraphs and spin glasses

We establish that in the large degree limit, the value of certain optimization problems on sparse random hypergraphs is determined by an appropriate Gaussian optimization problem. This approach was initiated in Dembo et al. (2016) for extremal cuts of graphs. The usefulness of this technique is further illustrated by deriving the optimal value for Max q-cut on graphs, Max XORSAT on Erdős–Renyi hypergraphs, and the min-bisection the min-bisection for the Stochastic Block Model.