cssi/SciSciGPT-SciSciNet huggingface dataset:
Detecting antagonistic and allied communities on social media

Community detection on social media has attracted considerable attention for many years. However, existing methods do not reveal the relations between communities. Communities can form alliances or engage in antagonisms due to various factors, e.g., shared or conflicting goals and values. Uncovering such relations can provide better insights to understand communities and the structure of social media. According to social science findings, the attitudes that members from different communities express towards each other are largely shaped by their community membership. Hence, we hypothesize that inter-community attitudes expressed among users in social media have the potential to reflect their inter-community relations. Therefore, we first validate this hypothesis in the context of social media. Then, inspired by the hypothesis, we develop a framework to detect communities and their relations by jointly modeling users' attitudes and social interactions. We present experimental results using three real-world social media datasets to demonstrate the efficacy of our framework.
Chord Recognition in Symbolic Music: A Segmental CRF Model, Segment-Level Features, and Comparative Evaluations on Classical and Popular Music

We present a new approach to harmonic analysis that is trained to segment music into a sequence of chord spans tagged with chord labels. Formulated as a semi-Markov Conditional Random Field (semi-CRF), this joint segmentation and labeling approach enables the use of a rich set of segment-level features, such as segment purity and chord coverage, that capture the extent to which the events in an entire segment of music are compatible with a candidate chord label. The new chord recognition model is evaluated extensively on three corpora of Western classical music and a newly created corpus of rock music. Experimental results show that the semi-CRF model performs substantially better than previous approaches when trained on a sufficient number of labeled examples and remains competitive when the amount of training data is limited.
Limits on the Power of Garbling Techniques for Public-Key Encryption

Understanding whether public-key encryption can be based on one-way functions is a fundamental open problem in cryptography. The seminal work of Impagliazzo and Rudich [STOC’89] shows that black-box constructions of public-key encryption from one-way functions are impossible. However, this impossibility result leaves open the possibility of using non-black-box techniques for achieving this goal.
GIVE: portable genome browsers for personal websites.

Growing popularity and diversity of genomic data demand portable and versatile genome browsers. Here, we present an open source programming library called GIVE that facilitates the creation of personalized genome browsers without requiring a system administrator. By inserting HTML tags, one can add to a personal webpage interactive visualization of multiple types of genomics data, including genome annotation, “linear” quantitative data, and genome interaction data. GIVE includes a graphical interface called HUG (HTML Universal Generator) that automatically generates HTML code for displaying user chosen data, which can be copy-pasted into user’s personal website or saved and shared with collaborators. GIVE is available at: https://www.givengine.org/ .
On the possible time singularities for the 3D Navier–Stokes equations

Abstract We prove a local-in-time regularity criterion for the 3D Navier–Stokes equations. In particular, it follows from the criterion that the Hausdorff dimension of possible singular times of Leray–Hopf weak solutions u ∈ L t r B s , ∞ α for some α > 0 , s > 3 and r > 2 is less than r 2 ( 3 s + 2 r − α − 1 ) . The main contribution is that we do not assume the suitability of weak solutions.
Improving estimation accuracy of aggregate queries on data cubes

In this paper, we investigate the problem of estimation of a target database from summary databases derived from a base data cube. We show that such estimates can be derived by choosing a primary database with the desired target measure but not the desired dimensions, and use a proxy database to estimate the results. This technique is common in statistics, but an important issue we are addressing is the accuracy of these estimates. Specifically, given multiple primary and multiple proxy databases, the problem is how to select the primary and proxy databases that will generate the most accurate target database estimation possible. We propose an algorithmic approach which makes use of the principles of information entropy for determining the steps to select or compute the primary and proxy databases that provide the most accurate target database. We show that the primary database with the largest number of cells in common with the target database and the proxy database provides the more accurate estimates. We prove that this is consistent with maximizing the entropy. We provide some experimental results on the accuracy of the target database estimation in order to verify our results. Furthermore, we investigate the accuracy results in cases where the dimensions are defined over a hierarchy of categories and roll-up and drill-down operations are needed to generate the desired target results.
El recurso de protección y sus innovaciones procesales

1. QUE ES EL RECURSO DE PROTECCION (R. DE P.). 1.1: Definicion. 1.2: Trascendencia. 1.3: Entorno Iberoamericano. 2. CARACTERIZACION DEL R. DE P. 2.1: Puesta en valor de determinados derechos. 2.2. Rango Constitucional. 2.3: Meritos Procesales. 2.3.1. Informalidad . 2.3.2 Inquisitoriedad. 2.3.3: Unilateralidad. 2.3.4: Brevedad y concentracion. 2.3.5: Amplitud. 2.3.6: Provisionalidad. 3. INNOVACIONES PROCESALES. 3.1: Habilitacion constitucional del A.C. No 3. 3.2: Virtual Inconstitucionalidad del A.A. de 1992. 3.3. Legitimacion del A.A.-92. 3.4: Innovaciones relevantes. 3.6.1: Computo del plazo. 3.6.2: Admisibilidad del recurso. 3.6.3: Agregacion a la tabla. 3.6.4.: Orden de no innovar. 3.6.5: El recurrido como "parte". 3.6.6: Plazo para fallar. e.6.7 : Plazo para apelar. 1.6.8: Tramitacion en 2a instancia. 3.6.9: Condena en costas. 4. LAS REFORMAS PENDIENTES. 4.1: Reformas constitucionales. 4.2: Reformas procesales. 4.3: Reforma de la competencia relativa. 5. CONCLUSIONES.
Unsupervised Learning of Syntactic Structure with Invertible Neural Projections

Unsupervised learning of syntactic structure is typically performed using generative models with discrete latent variables and multinomial parameters. In most cases, these models have not leveraged continuous word representations. In this work, we propose a novel generative model that jointly learns discrete syntactic structure and continuous word representations in an unsupervised fashion by cascading an invertible neural network with a structured generative prior. We show that the invertibility condition allows for efficient exact inference and marginal likelihood computation in our model so long as the prior is well-behaved. In experiments we instantiate our approach with both Markov and tree-structured priors, evaluating on two tasks: part-of-speech (POS) induction, and unsupervised dependency parsing without gold POS annotation. On the Penn Treebank, our Markov-structured model surpasses state-of-the-art results on POS induction. Similarly, we find that our tree-structured model achieves state-of-the-art performance on unsupervised dependency parsing for the difficult training condition where neither gold POS annotation nor punctuation-based constraints are available.
Efficient Projection onto the Perfect Phylogeny Model

Several algorithms build on the perfect phylogeny model to infer evolutionary trees. This problem is particularly hard when evolutionary trees are inferred from the fraction of genomes that have mutations in different positions, across different samples. Existing algorithms might do extensive searches over the space of possible trees. At the center of these algorithms is a projection problem that assigns a fitness cost to phylogenetic trees. In order to perform a wide search over the space of the trees, it is critical to solve this projection problem fast. In this paper, we use Moreau's decomposition for proximal operators, and a tree reduction scheme, to develop a new algorithm to compute this projection. Our algorithm terminates with an exact solution in a finite number of steps, and is extremely fast. In particular, it can search over all evolutionary trees with fewer than 11 nodes, a size relevant for several biological problems (more than 2 billion trees) in about 2 hours.
Learning Beam Search Policies via Imitation Learning

Beam search is widely used for approximate decoding in structured prediction problems. Models often use a beam at test time but ignore its existence at train time, and therefore do not explicitly learn how to use the beam. We develop an unifying meta-algorithm for learning beam search policies using imitation learning. In our setting, the beam is part of the model and not just an artifact of approximate decoding. Our meta-algorithm captures existing learning algorithms and suggests new ones. It also lets us show novel no-regret guarantees for learning beam search policies.
IotSan: fortifying the safety of IoT systems

Today's IoT systems include event-driven smart applications (apps) that interact with sensors and actuators. A problem specific to IoT systems is that buggy apps, unforeseen bad app interactions, or device/communication failures, can cause unsafe and dangerous physical states. Detecting flaws that lead to such states, requires a holistic view of installed apps, component devices, their configurations, and more importantly, how they interact. In this paper, we design IotSan, a novel practical system that uses model checking as a building block to reveal "interaction-level" flaws by identifying events that can lead the system to unsafe states. In building IotSan, we design novel techniques tailored to IoT systems, to alleviate the state explosion associated with model checking. IotSan also automatically translates IoT apps into a format amenable to model checking. Finally, to understand the root cause of a detected vulnerability, we design an attribution mechanism to identify problematic and potentially malicious apps. We evaluate IotSan on the Samsung SmartThings platform. From 76 manually configured systems, IotSan detects 147 vulnerabilities. We also evaluate IotSan with malicious SmartThings apps from a previous effort. IotSan detects the potential safety violations and also effectively attributes these apps as malicious.
A Handheld MEMS-Scanned in Vivo Optical-Sectioning Microscope for Early Detection and Surgical Guidance

A miniature line-scanned (LS) dual-axis confocal (DAC) microscope, with a 12-mm diameter distal tip, has been developed for high-speed (>15 Hz) microscopic imaging of tissue surfaces up to a depth of ∼ 150 μm.
Towards automating precision studies of clone detectors

Current research in clone detection suffers from poor ecosystems for evaluating precision of clone detection tools. Corpora of labeled clones are scarce and incomplete, making evaluation labor intensive and idiosyncratic, and limiting inter-tool comparison. Precision-assessment tools are simply lacking. We present a semiautomated approach to facilitate precision studies of clone detection tools. The approach merges automatic mechanisms of clone classification with manual validation of clone pairs. We demonstrate that the proposed automatic approach has a very high precision and it significantly reduces the number of clone pairs that need human validation during precision experiments. Moreover, we aggregate the individual effort of multiple teams into a single evolving dataset of labeled clone pairs, creating an important asset for software clone research.
Configural Frequency Analysis

Configural Frequency Analysis (CFA) is a method for the analysis of cross-classifications of categorical variables. Using CFA, one examines individual cells or groups of cells of cross-classifications with the goal of determining whether they contain more or fewer cases than expected based on some chance model. The specification of the chance model determines the interpretation of results. Depending on chance model, cells with more or fewer cases than expected can be interpreted as indicative of local associations, but also of predictor-criterion relationships; they allow one to distinguish between groups, or they reflect typical and atypical patterns of change over time. Keywords: antitype; base model; configural frequency analysis; deviation from independence; α protection; sampling scheme; type
Discrete choice under risk with limited consideration

This paper is concerned with learning decision-makers' preferences using data on observed choices from a finite set of risky alternatives. We propose a discrete choice model with unobserved heterogeneity in consideration sets and in standard risk aversion. We obtain sufficient conditions for the model's semi-nonparametric point identification, including in cases where consideration depends on preferences and on some of the exogenous variables. Our method yields an estimator that is easy to compute and is applicable in markets with large choice sets. We illustrate its properties using a dataset on property insurance purchases.
Inspection Regimes and Regulatory Compliance: How Important is the Element of Surprise?

Abstract Regulatory compliance is often promoted via unannounced inspections where firms found to be in violation of environmental, health, or safety regulations face punishments. When compliance is costly to firms, a key aspect of this approach is that the timing of inspections is unannounced and difficult to anticipate, lest firms comply only when they believe an inspection is likely. With data from Los Angeles (LA) County food-service health inspections, I estimate how the (in)ability to anticipate inspection timing affects compliance using a novel approach. Many facilities such as hotels, grocery stores, or food courts, consist of multiple food-service establishments sharing a single physical location. Multiple establishments within a single facility are commonly, though not always, inspected on the same day; meaning all but one of the establishments involved likely anticipate the timing of their next inspection to a considerable extent. Within such facilities, I show that establishments perform significantly worse on days in which they receive the sole inspection conducted at their facility. These sole inspections detect 7.75% more violations, 9.1% more inspection score point deductions, and 16.3% more major critical violations (the most severe violations of the county health code).
Bush, Robert R †

This article has no abstract. Keywords: mathematical psychology; linear models; Mosteller
Long-Term Diabetic Microenvironment Augments the Decay Rate of Capsaicin-Induced Currents in Mouse Dorsal Root Ganglion Neurons

Individuals with end-stage diabetic peripheral neuropathy present with decreased pain sensation. Transient receptor potential vanilloid type 1 (TRPV1) is implicated in pain signaling and resides on sensory dorsal root ganglion (DRG) neurons. We investigated the expression and functional activity of TRPV1 in DRG neurons of the Ins2+/Akita mouse at 9 months of diabetes using immunohistochemistry, live single cell calcium imaging, and whole-cell patch-clamp electrophysiology. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence assay was used to determine the level of Reactive Oxygen Species (ROS) in DRGs. Although TRPV1 expressing neuron percentage was increased in Ins2+/Akita DRGs at 9 months of diabetes compared to control, capsaicin-induced Ca2+ influx was smaller in isolated Ins2+/Akita DRG neurons, indicating impaired TRPV1 function. Consistently, capsaicin-induced Ca2+ influx was decreased in control DRG neurons cultured in the presence of 25 mM glucose for seven days versus those cultured with 5.5 mM glucose. The high glucose environment increased cytoplasmic ROS accumulation in cultured DRG neurons. Patch-clamp recordings revealed that capsaicin-activated currents decayed faster in isolated Ins2+/Akita DRG neurons as compared to those in control neurons. We propose that in poorly controlled diabetes, the accelerated rate of capsaicin-sensitive TRPV1 current decay in DRG neurons decreases overall TRPV1 activity and contributes to peripheral neuropathy.
Price Competition with LTE-U and WiFi

LTE-U is an extension of the Long Term Evolution (LTE) standard for operation in unlicensed spectrum. LTE-U differs from WiFi, the predominant technology used in unlicensed spectrum in that it utilizes a duty cycle mode for accessing the spectrum and allows for a more seamless integration with LTE deployments in licensed spectrum. There have been a number of technical studies on the co-existence of LTE-U and WiFi in unlicensed spectrum In this paper, we instead investigate the impact of such a technology from an economic perspective. We consider a model in which an incumbent service provider (SP) deploys a duty cycle-based technology like LTE-U in an unlicensed band along with operating in a licensed band and competes with one or more entrants that only operate in the unlicensed band using a different technology like WiFi. We characterize the impact of a technology like LTE-U on the market outcome and show that the welfare impacts of this technology are subtle, depending in part on the amount of unlicensed spectrum and number of entrants. We also investigate the impact of the duty cycle and the portion of unlicensed spectrum used by the technology.
Pituitary response to early follicular-phase minidose gonadotropin releasing hormone agonist (GnRHa) therapy: evidence for a second flare.

Purpose: Our purpose was to determine the pituitary response to minidose follicular-phase GnRHa and see if a second flare can be achieved.
Decentralized smart surveillance through microservices platform

Connected societies require reliable measures to assure the safety, privacy, and security of members. Public safety technology has made fundamental improvements since the first generation of surveillance cameras were introduced, which aims to reduce the role of observer agents so that no abnormality goes unnoticed. While the edge computing paradigm promises solutions to address the shortcomings of cloud computing, e.g., the extra communication delay and network security issues, it also introduces new challenges. One of the main concerns is the limited computing power at the edge to meet the on-site dynamic data processing. In this paper, a Lightweight IoT (Internet of Things) based Smart Public Safety (LISPS) framework is proposed on top of microservices architecture. As a computing hierarchy at the edge, the LISPS system possesses high flexibility in the design process, loose coupling to add new services or update existing functions without interrupting the normal operations, and efficient power balancing. A real-world public safety monitoring scenario is selected to verify the effectiveness of LISPS, which detects, tracks human objects and identify suspicious activities. The experimental results demonstrate the feasibility of the approach.
Competitive Governance and Displacement Decisions Under Rebel Rule: Evidence from the Islamic State in Iraq:

When rebel groups with state-building ambitions capture territory, who stays and why? Through semi-structured interviews and an original household survey in the Iraqi city of Mosul, which was contr...
Lipid-shelled microbubbles for ultrasound-triggered release of bioactive gases to treat stroke and cardiovascular disease

Ischemia-reperfusion-induced neurological injury is a primary cause of stroke disability. Xenon (Xe), a bioactive gas, has potential as an effective and nontoxic neuroprotectant for the treatment of ischemic stroke. Nitric oxide (NO) is a potent bioactive gas capable of inducing vasodilatory, anti-inflammatory, neuroprotectant and bactericidal effects. The goal of this work was to develop lipid-shelled microbubbles for site-specific release of Xe or NO upon pulsed ultrasound exposure. Gas-loaded microbubbles were synthesized by high-shear mixing of a lipid dispersion in a vial that contained, Xe or NO, and octafluoropropane (OFP) in combination. Attenuation spectroscopy measurements demonstrate the feasibility of 6-MHz pulsed Doppler ultrasound-triggered release of Xe or NO from microbubbles. The addition of OFP in the lipid-shelled microbubbles increased the number density, size, and stability of the microbubbles, particularly in undersaturated saline. Gas chromatography mass spectrometry was employed to measure Xe dose (127 ± 29 μl Xe/mg lipid). The payload of NO in the microbubbles (97 ± 12 μl NO/mg lipid) was assessed using an amperometric sensor. Intravenous administration of microbubbles carrying a neuroprotective or a vasodilatory gas in combination with ultrasound exposure has potential as a novel noninvasive strategy for local therapeutic delivery to modulate the effects or duration of cerebral ischemia.Ischemia-reperfusion-induced neurological injury is a primary cause of stroke disability. Xenon (Xe), a bioactive gas, has potential as an effective and nontoxic neuroprotectant for the treatment of ischemic stroke. Nitric oxide (NO) is a potent bioactive gas capable of inducing vasodilatory, anti-inflammatory, neuroprotectant and bactericidal effects. The goal of this work was to develop lipid-shelled microbubbles for site-specific release of Xe or NO upon pulsed ultrasound exposure. Gas-loaded microbubbles were synthesized by high-shear mixing of a lipid dispersion in a vial that contained, Xe or NO, and octafluoropropane (OFP) in combination. Attenuation spectroscopy measurements demonstrate the feasibility of 6-MHz pulsed Doppler ultrasound-triggered release of Xe or NO from microbubbles. The addition of OFP in the lipid-shelled microbubbles increased the number density, size, and stability of the microbubbles, particularly in undersaturated saline. Gas chromatography mass spectrometry was employed to...
Democracy in America? Partisanship, Polarization, and the Robustness of Support for Democracy in the United States

Is support for democracy in the United States robust enough to deter undemocratic behavior by elected politicians? We develop a model of the public as a democratic check and evaluate it using two empirical strategies: an original, nationally representative candidate-choice experiment in which some politicians take positions that violate key democratic principles, and a natural experiment that occurred during Montana’s 2017 special election for the U.S. House. Our research design allows us to infer Americans’ willingness to trade-off democratic principles for other valid but potentially conflicting considerations such as political ideology, partisan loyalty, and policy preferences. We find the U.S. public’s viability as a democratic check to be strikingly limited: only a small fraction of Americans prioritize democratic principles in their electoral choices, and their tendency to do so is decreasing in several measures of polarization, including the strength of partisanship, policy extremism, and candidate platform divergence. Our findings echo classic arguments about the importance of political moderation and cross-cutting cleavages for democratic stability and highlight the dangers that polarization represents for democracy.
Interim Effective Tax Rate Estimates and Internal Control Quality

This study examines whether the volatility of interim estimates of the annual effective tax rate (ETR) provides ex ante information about the quality of firms' internal control environments. Recent research suggests that some firms selectively disclose internal control weaknesses (ICWs). Given the negative consequences associated with ICWs, it is important for capital market participants to be able to identify firms with ineffective internal controls in a timely manner. We find that firms with more volatile annual ETR estimates are more likely to report both tax‐ and nontax‐related ICWs in the current year. Our results also indicate that the volatility of annual ETR estimates declines following the remediation of tax‐related ICWs, but not following the remediation of nontax‐related ICWs. In addition, we find that ETR volatility in the current year is associated with the likelihood that a firm will report an ICW in the following year. Finally, we provide evidence that the volatility of annual ETR estimates is associated with the likelihood that a firm has an undisclosed ICW. In combination, our results suggest that the volatility of interim estimates of the annual ETR provides an ex ante signal of the likelihood that a firm's internal controls are ineffective. Estimations provisoires du taux d'imposition effectif et qualite du controle interne Les auteurs se demandent si la volatilite des estimations provisoires du taux d'imposition effectif (TIE) annuel fournit de l'information anticipee au sujet de la qualite de l'environnement de controle interne des societes. Selon de recentes etudes, certaines societes communiquent de maniere selective l'information relative aux faiblesses du controle interne. Compte tenu des repercussions negatives associees a ces faiblesses, il importe pour les participants aux marches de capitaux de pouvoir reperer rapidement les societes dont le controle interne est inefficace. Les auteurs constatent que les societes dont les estimations du TIE annuel sont plus volatiles sont davantage susceptibles de faire etat de faiblesses du controle interne, que ces faiblesses soient liees ou non a l'impot, dans l'annee courante. Les resultats qu'obtiennent les auteurs indiquent egalement que la volatilite des estimations du TIE annuel decline une fois corrigees les faiblesses du controle interne lorsque ces faiblesses sont liees a l'impot mais non lorsqu'elles ne le sont pas. Ils relevent en outre que la volatilite du TIE dans l'annee courante est associee a la probabilite qu'une societe fasse etat d'une faiblesse du controle interne l'annee suivante. Enfin, ils demontrent que la volatilite des estimations du TIE annuel est associee a la probabilite qu'une societe ait une faiblesse du controle interne dont elle n'a pas fait etat. Dans l'ensemble, les resultats de l'etude paraissent indiquer que la volatilite des estimations provisoires du TIE annuel donne un signal precurseur de la probabilite que le controle interne d'une societe soit inefficace.
Synthesis and characterization of two crystallographic forms of Ag0.79VS2

A previously unreported compound, Ag{sub 0.79}VS{sub 2}, has been synthesized; its structure and elementary properties are reported. Ag{sub 0.79}VS{sub 2} crystallizes in two forms, designated as the α and β, related to the 1s-InTaS{sub 2} structure. Single crystal x-ray diffraction shows the α form to have a single layer hexagonal structure with a unit cell of 3.213(3) A×7.809(6) A, consisting of layers of edge-shared VS{sub 6} triangular prisms separated by layers of Ag. The β form is similar but has an a{sub o}√((3)) supercell in the basal plane, yielding a unit cell of 5.573(5) A×7.822(6) A. Both forms have disordered and displaced silver in the basal plane, but the β form has partial ordering of its silver sublattice and in-plane vanadium trimers. Resistivity measurements show metallic temperature dependence with an unusual hysteresis between 210 K and 130 K. Magnetic susceptibility measurements show Pauli Paramagnetic behavior. The Seebeck coefficient at 300 K is 42 µV/K. - Graphical abstract: Red=Vanadium, Gray=Silver, Yellow=Sulfur. Top left is α-Ag{sub 0.79}VS{sub 2} in the 1s-InTaS{sub 2} structure type. Top right: 2a×2b projection down the c-axis with displacement ellipsoids (50% probability) of atoms drawn to illustrate the split silver model. Bottom left is β-Ag{sub 0.79}VS{sub 2} havingmore » the a{sub o}√((3)) supercell. Bottom right: projection along the c-axis, displacement ellipsoids of atoms drawn. - Highlights: • Two crystallographic forms of Ag{sub 0.79}VS{sub 2}, designated α and β, are reported. • They are found to crystallize in the 1s-InTaS{sub 2} structure type. • β-Ag{sub 0.79}VS{sub 2} has partial ordering of the Ag sublattice and vanadium trimers. • Ag{sub 0.79}VS{sub 2} shows Pauli Paramagnetic behavior, a Seebeck coefficient of 42 µV/K at 300 K. • Ag{sub 0.79}VS{sub 2} shows metallic resistivity with an unusual hysteresis between 210 K and 130 K.« less
B-(2-Azido-2-propenyl)-1,3,2-dioxaborinane: A novel reagent for allylboration

Abstract A new allylborating agent, B -(2-azido-2-propenyl)-1,3,2-dioxaborinane, has been synthesized by the reaction of iodine azide with B-allyl-1,3,2-dioxaborinane, followed by dehydroiodination with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This reagent allylborates representative aldehydes to provide, after hydrogen peroxide oxidation, the corresponding 2-azido-1-alken-4-ols in 64–75% isolated yields.
N4H9Cu7S4: a hydrazinium-based salt with a layered Cu7S4- framework.

Crystals of a hydrazinium-based copper(I) sulfide salt, N4H9Cu7S4 (1), have been isolated by an ambient temperature solution-based process. In contrast to previously reported hydrazinium salts of main-group metal chalcogenides, which consist of isolated metal chalcogenide anions, and ACu7S4 (A = NH4+, Rb+, Tl+, K+), which contains a more three-dimensional Cu7S4- framework with partial Cu-site occupancy, the structure of 1 [P21, a = 6.8621(4) A, b = 7.9851(4) A, c = 10.0983(5) A, β = 99.360(1)°, Z = 2] is composed of extended two-dimensional Cu7S4- slabs with full Cu-site occupancy. The Cu7S4- slabs are separated by a mixture of hydrazinium and hydrazine moieties. Thermal decomposition of 1 into copper(I) sulfide proceeds at a significantly lower temperature than that observed for analogous hydrazinium salts of previously considered metal chalcogenides, completing the transition at temperatures as low as 120 °C. Solutions of 1 may be used in the solution deposition of a range of Cu-containing chalcogenide ...
Effects of reaction conditions on quinone/diquinone product ratios in the oxidation of 1,4-dimethoxybenzene derivatives with ceric ammonium nitrate

Abstract Proper choice of reaction conditions allows formation of either the quinone or corresponding diquinone as the major product upon treatment of 2-alkyl-1,4-dimethoxybenzenes with ceric ammonium nitrate.
Synthesis of phakellistatin 13 and oxidation to phakellistatin 3 and isophakellistatin 3.

The natural product phakellistatin 13 cyclo-(TrpProPheGlyProThrLeu) was synthesized. Photosensitized oxidation of phakellistatin 13 gave the natural products phakellistatin 3 and isophakellistatin 3, demonstrating for the first time that a tryptophan residue can be directly converted to the corresponding 3a-hydroxypyrrolo[2,3-b]indoline in a full length peptide. Competitive oxidation of the indoline product was identified as the cause of low mass balance and is probably the source of low mass balance in the oxidative cyclization of all tryptamine derivatives.
Synthesis and Crystal Structure of a New Vanadyl Phosphate [H0.6(VO)3(PO4)3(H2O)3]·4H2O and Its Conversion to Porous Products

Yellow layered VOPO4·2H2O was found to spontaneously, but slowly, convert to a green phase [H0.6(VO)3(PO4)3(H2O)3]·4H2O upon standing in air. This phase could be prepared hydrothermally from V2O5 +...
Mechanisms and kinetics models for hydrocarbon pyrolysis

Abstract Kinetics models based on the governing mechanism for a multi-step chemical reaction provide insight into the underlying chemistry and they can be extrapolated more confidently than can empirical kinetics models. The field of thermal hydrocarbon chemistry is sufficiently mature that the types of free-radical reactions that are important have been reasonably well elucidated. Moreover, rate constants for many elementary reactions have been measured experimentally, and rate constants for other reactions can be estimated from thermochemical kinetics considerations. These circumstances facilitate the development of quantitative mechanism-based mathematical models for hydrocarbon pyrolysis. This paper provides an overview of the current approaches for mechanistic modeling of hydrocarbon pyrolysis. The steps involved in developing both analytical and numerical models are described and illustrated with examples from the literature.
High-resolution ISR amplicon sequencing reveals personalized oral microbiome.

Sequencing of the 16S rRNA gene has been the standard for studying the composition of microbial communities. While it allows identification of bacteria at the level of species, this method does not usually provide sufficient information to resolve communities at the sub-species level. Species-level resolution is not adequate for studies of transmission or stability or for exploring subspecies variation in disease association. Strain level analysis using whole metagenome shotgun sequencing has significant limitations that can make it unsuitable for large-scale studies. Achieving sufficient depth of sequencing can be cost-prohibitive, and even with adequate coverage, deconvoluting complex communities such as the oral microbiota is computationally very challenging. Thus, there is a need for high-resolution, yet cost-effective, high-throughput methods for characterizing microbial communities. Significant improvement in resolution for amplicon-based bacterial community analysis was achieved by combining amplicon sequencing of a high-diversity marker gene, the ribosomal 16-23S intergenic spacer region (ISR), with a probabilistic error modeling based denoising algorithm, DADA2. The resolving power of this new approach was compared to that of both standard and high-resolution 16S-based approaches using a set of longitudinal subgingival plaque samples. The ISR strategy resulted in a 5.2-fold increase in community resolution compared to reference-based 16S rRNA gene analysis and showed 100% accuracy in predicting the correct source of a clinical sample. Individuals’ microbial communities were highly personalized, and although they exhibited some drift in membership and levels over time, that difference was always smaller than the differences between any two subjects, even after 1 year. The construction of an ISR database from publicly available genomic sequences allowed us to explore genomic variation within species, resulting in the identification of multiple variants of the ISR for most species. The ISR approach resulted in significantly improved resolution of communities and revealed a highly personalized human oral microbiota that was stable over 1 year. Multiple ISR types were observed for all species examined, demonstrating a high level of subspecies variation in the oral microbiota. The approach is high-throughput, high-resolution yet cost-effective, allowing subspecies-level community fingerprinting at a cost comparable to that of 16S rRNA gene amplicon sequencing. It will be useful for a range of applications that require high-resolution identification of organisms, including microbial tracking, community fingerprinting, and potentially for identification of virulence-associated strains.
Proximity effects in the palladium-catalyzed substitution of aryl fluorides.

The aryl fluoride bond has long been considered inert toward Pd-catalyzed insertion reactions. This paper reports for the first time that aryl fluorides bearing an o-carboxylate group can undergo P...
n‐Butyl by‐products in the syntheses of 2‐(1‐ and 2‐naphthyl)pyridines via lithiation

By-products in the syntheses of 2-(1- and 2-naphthyl)pyridines by successive treatments of 1- and 2-bromonaphthalenes with (a) n-butyllithium in ether and (b) pyridine are identified as 5-butyl-2-(1-naphthyl)pyridine and, tentatively, 5-butyl-2-(2-naphthyl)pyridine, respectively. It is proposed that these by-products result from reaction of intermediate compounds 1-lithio-2-naphthyl-1,2-dihydropyridines and 1-bromobutane.
Stereoselective construction of quaternary carbon centers by three component coupling reactions.

TiCl4 promoted coupling reactions of pyruvates with vinyl ethers such as 3,4-dihydro-2H-pyran or 2,3-dihydrofuran constructed quaternary carbon centers stereoselectively.
A convenient racemic synthesis of two isomeric tetrahydropyridyl alkaloids: Isoanatabine and anatabine

The procedure for the synthesis of isoanatabine (VI) is extended to the synthesis of anatabine (XI).
Synthesis of polyhydroxylated pyrrolizidine alkaloids of the alexine family by tandem ring-closing metathesis-transannular cyclization. (+)-Australine.

Dienes 23 and 54, prepared from epoxy alcohol 9 via oxazolidinones 15 and 51, respectively, underwent ring-closing metathesis with Grubbs's catalyst to give azacyclooctenes 26 and 55. Treatment of each azacyclooctene with m-chloroperoxybenzoic acid afforded β-epoxide 28 from 26 and α-epoxide 61 from 60. Basic hydrolysis of each of these oxazolidinones was accompanied by transannular attack at the epoxide by nitrogen, resulting in 2-(O-benzyl)-7-deoxyalexine (29) and 1,2-di-(O-benzyl)australine (62). The latter was converted to the alkaloid australine (3) upon hydrogenolysis. Attempts to effect ring-closing metathesis of dienes 37, 38, and 46 were unsuccessful, suggesting that, while one allylic oxygen substituent can be tolerated by Grubbs's catalyst, two cannot.
Development of a Method for the Reductive Cyclization of Enones by a Titanium Catalyst

An effective protocol in which bis(trimethylphosphine)titanocene is used to catalyze the reductive cyclization of enones to cyclopentanols via a metallacyclic intermediate has been developed. The key step in the process is the cleavage of the titanium−oxygen bond in the metallacycle by a silane to regenerate the catalyst. Mechanistic aspects of the reaction are discussed and the diastereoselectivity of the transformation is studied using both achiral and chiral substrates. The scope and limitations of the procedure are described. An in situ protocol for the generation of the air- and moisture-sensitive catalyst has also been developed. This work demonstrates, for the first time, the viability of using an early transition metal complex to catalyze the reductive cyclization of an alkene with a heteroatom-containing functional group.
Low base-substitution mutation rate in the germline genome of the ciliate Tetrahymena thermophila

Mutation is the ultimate source of all genetic variation and is, therefore, central to evolutionary change. Previous work on Paramecium tetraurelia found an unusually low germline base-substitution mutation rate in this ciliate. Here, we tested the generality of this result among ciliates using Tetrahymena thermophila. We sequenced the genomes of 10 lines of T. thermophila that had each undergone approximately 1,000 generations of mutation accumulation (MA). We applied an existing mutation-calling pipeline and developed a new probabilistic mutation detection approach that directly models the design of an MA experiment and accommodates the noise introduced by mismapped reads. Our probabilistic mutation-calling method provides a straightforward way of estimating the number of sites at which a mutation could have been called if one was present, providing the denominator for our mutation rate calculations. From these methods, we find that T. thermophila has a germline base-substitution mutation rate of 7.61 × 10 - 12 per-site, per cell division, which is consistent with the low base-substitution mutation rate in P. tetraurelia. Over the course of the evolution experiment, genomic exclusion lines derived from the MA lines experienced a fitness decline that cannot be accounted for by germline base-substitution mutations alone, suggesting that other genetic or epigenetic factors must be involved. Because selection can only operate to reduce mutation rates based upon the "visible" mutational load, asexual reproduction with a transcriptionally silent germline may allow ciliates to evolve extremely low germline mutation rates.
Reaction of (t‐BuGaCl2)2 with Ar′PHLi (Ar′ = 2,4,6‐t‐Bu3C6H2): Preparation of the chloride‐bridged dimer (t‐BuGa(Cl)P(H)Ar′)2

The reaction of (t-BuGaCl2)2 with Ar′P(H)Li (AR′ = 2,4,6-t-Bu3C6H2) affords the chloride-bridged dimer [t-BuGa(Cl)P(H)Ar′]2 (1). The structure of 1 has been established by X-ray crystallography. Compound 1, C44H78Cl2Ga2P2, crystallizes in the monoclinic space group P21/n with Z = 2, a = 10.468(1), b = 14.967(1), c = 16.182(2) A, and A = 94.48(1)β. The reaction of 1 with t-BuLi is described.
Noncentrosymmetric salt inclusion oxides: Role of salt lattices and counter ions in bulk polarity

The synthesis and structural features of a newly emerged class of salt-inclusion solids (SISs) are reviewed. The descriptive chemistry with respect to the role of ionic salt and its correlation with bulk noncentrosymmetricity and polarity of the covalent oxide lattice in question is discussed by means of structure analysis. These unprecedented discoveries have opened doors to novel materials synthesis via the utilities of salt-inclusion chemistry (SIC) that are otherwise known as the molten-salt approach. The result of these investigations prove that the bulk acentricity, or cancellation of which, can be accounted for from the perspective of ionic and/or salt lattices. Highlights: Black-Right-Pointing-Pointer Synthesis and structure of newly emerged salt-inclusion solids are reviewed. Black-Right-Pointing-Pointer Salt lattice and its symmetry correlation with polar framework are discussed. Black-Right-Pointing-Pointer Preservation of acentricity is accounted for from the perspective of ionic and salt lattices.
Social context modulates idiosyncrasy of behaviour in the gregarious cockroach Blaberus discoidalis

Individuals are different, but they can work together to perform adaptive collective behaviours. Despite emerging evidence that individual variation strongly affects group performance, it is less clear to what extent individual variation is modulated by participation in collective behaviour. We examined light avoidance (negative phototaxis) in the gregarious cockroach Blaberus discoidalis, in both solitary and group contexts. Cockroaches in groups exhibited idiosyncratic light-avoidance performance that persisted across days, with some individual cockroaches avoiding a light stimulus 75% of the time, and others avoiding the light just above chance (i.e. ∼50% of the time). These individual differences were robust to group composition. Surprisingly, these differences did not persist when individuals were tested in isolation, but returned when testing was once again done in groups. During the solo testing phase cockroaches exhibited individually consistent light-avoidance tendencies, but these differences were uncorrelated with performance in any group context. Therefore, we have observed not only that individual variation affects group-level performance, but also that whether or not a task is performed collectively can have a significant, predictable effect on how an individual behaves. That individual behavioural variation is modulated by whether a task is performed collectively has major implications for understanding variation in behaviours that are facultatively social, and it is essential that ethologists consider social context when evaluating individual behavioural differences.
Intramolecular [2+2] photocycloaddition of juxtaposed 4-pyridone moieties

Abstract Refluxing 4-hydroxypyridine and α,α′-dibromo-o-xylene in an ethanolic sodium ethoxide solution affords α,α′-di-(4-pyridon-1-yl)-o-xylene (1) which undergoes a novel [2+2] photocycloaddition reaction in 3:7 ethanol-ether giving cis,syn,cis-12,13-benzo-1,10-diazatetracyclo[8.4.2.05,15.06,16] hexadeca-2,8-diene-4,7-dione (2). The structure of 2 was determined by x-ray crystallographic analysis.
Synthesis of Methyl 7,9-Dimethyl-5-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-1-carboxylate and Its Analogues

A high-yielding five-step synthesis of the title compound, methyl 7,9-dimethyl-5-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-1-carboxylate, starting from 2,4-dimethylaniline was developed. This synthesis involved N-alkylation of 2,4-dimethyl­aniline with ethyl 4-bromobutyrate to obtain ethyl 4-[(2,4-dimethylphenyl)amino]butanoate. Carbamoylation of the latter followed by hydrolysis of the resulting ester provided 4-[(2,4-dimethylphenyl)(methoxycarbonyl)amino]butanoic acid. Activation of the carboxylic acid using thionyl chloride followed by intramolecular cyclization via a Friedel–Crafts reaction using aluminum trichloride provided the title compound in good yield. Analogues of the title compound were also prepared similarly.
Nucleon-nucleon interaction and isospin violation

The application of the chiral effective theory to processes with two or more nucleons is discussed. We gain a qualitative understanding of the gross features of nuclear physics and quantitative, testable postdictions and predictions involving photons and pions.
A convenient synthesis of 1-aryl-3-methyl-1,2,4-triazolin-5-ones from the reaction between acetone arylhydrazones and acetyl isocyanate

The reaction of acetone arylhydrazones with acetyl isocyanate gave the corresponding 4-acetyl-1-aryl-3,3-dimethyl-1,2,4-triazolidin-5-ones which eliminated acetone upon acidic hydrolysis to give 1-aryl-3-methyl-1,2,-4-triazolin-5-ones. The above transformation can be achieved in one pot by a simple solvent swap.
Solid-State NMR Spectroscopy

Due to the development of new techniques and further increase of magnetic field strength available for commercial applications, solid-state NMR spectroscopy became a routine method for the characterization of zeolites. As an important advantage, solid-state NMR spectroscopy allows the investigation of the local structure of nuclei in the solids under study. The specific behavior of zeolites often depends on local effects, such as framework defects, the substitution of framework atoms, guest compounds etc. Therefore, solid-state NMR spectroscopy is a widely applied analytical method for delivering structure data, which are complementary to those of diffraction methods suitable for investigating the long-range order. While early solid-state NMR spectroscopic studies often focused on the characterization of the zeolite framework in the as-synthesized and hydrated state, an increasing number of recent works is dealing with the investigation of the framework of dehydrated and calcined zeolites and of surface sites, i.e., on the determination of their concentration, strength, and accessibility. In all these applications, the advantage of solid-state NMR spectroscopy to be a quantitative method is utilized. The present chapter demonstrates the fundamentals, various techniques, and most important applications of solid-state NMR spectroscopy making this method to an important tool of research in zeolite science.
Efficient Two-Dimensional Line Spectrum Estimation Based on Decoupled Atomic Norm Minimization

Abstract This paper presents an efficient optimization technique for gridless 2-D line spectrum estimation, named decoupled atomic norm minimization (D-ANM). The framework of atomic norm minimization (ANM) is considered, which has been successfully applied in 1-D problems to allow super-resolution frequency estimation for correlated sources even when the number of snapshots is highly limited. The state-of-the-art 2-D ANM approach vectorizes the 2-D measurements to their 1-D equivalence, which incurs huge computational cost and may become too costly for practical applications. We develop a novel decoupled approach of 2-D ANM via semi-definite programming (SDP), which introduces a new matrix-form atom set to naturally decouple the joint observations in both dimensions without loss of optimality. Accordingly, the original large-scale 2-D problem is equivalently reformulated via two decoupled one-level Toeplitz matrices, which can be solved by simple 1-D frequency estimation with pairing. Compared with the conventional vectorized approach, the proposed D-ANM technique reduces the computational complexity by several orders of magnitude with respect to the problem size, at no loss of optimality. It also retains the benefits of ANM in terms of precise signal recovery, small number of required measurements, and robustness to source correlation. The complexity benefits are particularly attractive for large-scale antenna systems such as massive MIMO, radar signal processing and radio astronomy.