cssi/SciSciGPT-SciSciNet huggingface dataset:
Prolonged Late Permian–Early Triassic hyperthermal: failure of climate regulation?

The extreme warmth associated with the mass extinction at the PermianTriassic boundary was likely produced by a rapid build-up of carbon dioxide in the atmosphere from the eruption and emplacement ...
Evidence for a Pulsar Wind Nebula in the Type Ib Peculiar Supernova SN 2012au

We present an optical spectrum of the energetic Type Ib supernova (SN) 2012au obtained at an unprecedented epoch of 6.2 years after explosion. Forbidden transition emission lines of oxygen and sulfur are detected with expansion velocities of 2300 km/s. The lack of narrow H Balmer lines suggests that interaction with circumstellar material is not a dominant source of the observed late-time emission. We also present a deep Chandra observation that reveals no X-ray emission down to a luminosity of L_X < 2 x 10^{38} erg/s (0.5-10 keV). Our findings are consistent with the notion that SN 2012au is associated with a diverse subset of SNe, including long-duration gamma-ray burst SNe and superluminous SNe, harboring pulsar/magnetar wind nebulae that influence core-collapse explosion dynamics on a wide range of energy scales. We hypothesize that these systems may all evolve into a similar late-time phase dominated by forbidden oxygen transitions, and predict that emission line widths should remain constant or broaden a few per cent per year due to the acceleration of ejecta by the pulsar/magnetar bubble.
On the Universal Approximability and Complexity Bounds of Quantized ReLU Neural Networks

Compression is a key step to deploy large neural networks on resource-constrained platforms. As a popular compression technique, quantization constrains the number of distinct weight values and thus reducing the number of bits required to represent and store each weight. In this paper, we study the representation power of quantized neural networks. First, we prove the universal approximability of quantized ReLU networks on a wide class of functions. Then we provide upper bounds on the number of weights and the memory size for a given approximation error bound and the bit-width of weights for function-independent and function-dependent structures. Our results reveal that, to attain an approximation error bound of $\epsilon$, the number of weights needed by a quantized network is no more than $\mathcal{O}\left(\log^5(1/\epsilon)\right)$ times that of an unquantized network. This overhead is of much lower order than the lower bound of the number of weights needed for the error bound, supporting the empirical success of various quantization techniques. To the best of our knowledge, this is the first in-depth study on the complexity bounds of quantized neural networks.
Xrs2 and Tel1 Independently Contribute to MR-Mediated DNA Tethering and Replisome Stability.

Summary The yeast Mre11-Rad50-Xrs2 (MRX) complex has structural, signaling, and catalytic functions in the response to DNA damage. Xrs2, the eukaryotic-specific component of the complex, is required for nuclear import of Mre11 and Rad50 and to recruit the Tel1 kinase to damage sites. We show that nuclear-localized MR complex (Mre11-NLS) catalyzes homology-dependent repair without Xrs2, but MR cannot activate Tel1, and it fails to tether DSBs, resulting in sensitivity to genotoxins, replisome instability, and increased gross chromosome rearrangements (GCRs). Fusing the Tel1 interaction domain from Xrs2 to Mre11-NLS is sufficient to restore telomere elongation and Tel1 signaling to Xrs2-deficient cells. Furthermore, Tel1 stabilizes Mre11-DNA association, and this stabilization function becomes important for DNA damage resistance in the absence of Xrs2. Enforcing Tel1 recruitment to the nuclear MR complex fully rescues end tethering and stalled replication fork stability, and suppresses GCRs, highlighting important roles for Xrs2 and Tel1 to ensure optimal MR activity.
Targeted memory reactivation during sleep to strengthen memory for arbitrary pairings

A powerful way to investigate memory consolidation during sleep utilizes acoustic stimulation to reactivate memories. In multiple studies, Targeted Memory Reactivation (TMR) using sounds associated with prior learning improved later memory, as in recalling locations where objects previously appeared. In the present experiment, we examined whether a variant of the same technique could strengthen memory for the locations of pairs of objects. Each sound was naturally connected to one object from each pair, but we hypothesized that both memories could be improved with TMR. We first asked participants to memorize each of 50 pairs of objects by associating the two objects with each other and with the sound of one of the objects (e.g., cat-meow). Next, objects were presented in unique locations on a grid. Participants learned these locations in an adaptive procedure. During an afternoon nap, 25 of the sounds were quietly presented. In memory tests given twice before and twice after the nap, participants heard the sound for each object pair and were asked to recall the name of the second object and the locations of both objects. Forgetting scores were calculated using the mean difference between pre-nap and post-nap spatial recall errors. We found less forgetting after the nap for cued compared to non-cued objects. Additionally, the extent of forgetting tended to be similar for the two members of each pair, but only for cued pairs. Results thus substantiate the potential for sounds to reactivate spatial memories during sleep and thereby improve subsequent recall performance, even for multiple objects associated with a single sound and when participants must learn a novel sound-object association.
Trust development across levels of analysis: An embedded-agency perspective

This article advances a cross-level model of trust development. Drawing upon an embedded-agency perspective from institutional theory, we combine a top-down with a bottom-up approach, reflecting th...
Ease on Down the Code: Complex Collaborative Qualitative Coding Simplified with 'Code Wizard'

This paper describes the design and development of a preliminary qualitative coding tool as well as a method to improve the process of achieving inter-coder reliability (ICR) in small teams. Software applications that support qualitative coding do not sufficiently assist collaboration among coders and overlook some fundamental issues related to ICR. We propose a new dimension of collaborative coding called 'coders' certainty" and demonstrate its ability to illustrate valuable code disagreements that are missing from existing approaches. Through a case study, we describe the utility of our tool, Code Wizard, and how it helped a group of researchers effectively collaborate to code naturalistic observation data. We report the valuable lessons we learned from the development of our tool and method: (1) identifying coders' certainty constitutes an important part of determining the quality of data analysis and facilitates identifying overlapping and ambiguous codes, (2) making the details of coding process visible helps streamline the coding process and leads to a sense of ownership of the research results, and (3) there is valuable information hidden in coding disagreements that can be leveraged for improving the process of data analysis.
Using a hidden Markov model to measure earnings quality

Abstract We propose and validate a new measure of earnings quality based on a hidden Markov model. This measure, termed earnings fidelity, captures how faithful earnings signals are in revealing the true economic state of the firm. We estimate the measure using a Markov chain Monte Carlo procedure in a Bayesian hierarchical framework that accommodates cross-sectional heterogeneity. Earnings fidelity is positively associated with the forward earnings response coefficient. It significantly outperforms existing measures of quality in predicting two external indicators of low-quality accounting: restatements and Securities and Exchange Commission comment letters.
Is the pen mightier than the keyboard? The effect of online testing on measured student achievement

Abstract Nearly two dozen states now administer online exams to deliver testing to K-12 students. These tests have real consequences: their results feed into accountability systems, which have been used for more than a decade to hold schools and districts accountable for their students’ learning. We examine the rollout of computer-based testing in Massachusetts over 2 years to investigate test mode effects. Crucial to the study design is the state administering the same exam (PARCC) in online and offline formats each year during the transitional period. We find an online test penalty of about 0.10 standard deviations in math and 0.25 standard deviations in English language arts (ELA), which partially but not fully fades out in the second year of online testing.
Blameworthiness in Multi-Agent Settings

We provide a formal definition of blameworthiness in settings where multiple agents can collaborate to avoid a negative outcome. We first provide a method for ascribing blameworthiness to groups relative to an epistemic state (a distribution over causal models that describe how the outcome might arise). We then show how we can go from an ascription of blameworthiness for groups to an ascription of blameworthiness for individuals using a standard notion from cooperative game theory, the Shapley value. We believe that getting a good notion of blameworthiness in a group setting will be critical for designing autonomous agents that behave in a moral manner.
Bayesian modeling of abandonments in ticket queues

Ticket queues arise often in public and private sector operations. The service providers in ticket queues have limited information on customer abandonments because abandonment time data is interval censored. The censored nature of data poses challenges in modeling and analysis of abandonments and in developing staffing policies. To alleviate such challenges, we present a Bayesian framework for analysis of abandonments in ticket queues. In doing so, we propose parametric and semi-parametric modulated Poisson process models to describe the abandonment behavior and develop their Bayesian analysis using Markov chain Monte Carlo methods. We implement our models on actual abandonment data from a bank’ s ticket queue and illustrate how the proposed Bayesian framework can be used to provide insights for operations managers in predicting abandonments and in developing server allocation policies.
Implementation of an early warning indicator and intervention system

AbstractThis study focuses on the implementation of an early warning indicator and intervention system in 20 southern high schools. This model included a team of teachers, counselors, and student s...
Using Common Value Auction In Cultural Algorithm to Enhance Robustness and Resilience of Social Knowledge Distribution Systems

In Cultural Systems there are many ways to collect and distribute problem solving knowledge within social networks. Such mechanisms include games, auctions, and various voting mechanisms. Here, a new auction mechanism, Common Value Auctions, is presented. In this paper Common Value Auctions are used to distribute problem solving knowledge within a given model of social systems. These mechanisms are compared with the other distribution mechanisms in the solution of dynamic real-valued optimization problems. Specifically, their relative abilities to support the robustness and resilience of Cultural Systems in environments that vary in their dynamic complexity from static to chaotic are assessed. The Cultural Algorithms Toolkit (CAT) is used as a vehicle to generate real-valued dynamic problem landscapes of varying complexities. The results show that using the Common Value Auction in CAT4 has significant improvements over Weighted Voting methods (CAT2) in terms of both robustness and resilience across complexities that range from static to chaotic.
Darwin: A Genomics Coprocessor

Long read sequencing is promising as it provides knowledge of a full spectrum of mutations in the human genome and generates more contiguous de novo assemblies. But high error rate in long reads imposes a computational barrier for genome assembly. Darwin, a specialized coprocessor, which provides orders of magnitude speedup over conventional processors in long read assembly, can eliminate this barrier.
Review of Sublimation Thermodynamics of Polycyclic Aromatic Compounds and Heterocycles

This review details sublimation vapor pressure and thermodynamic data on 85 polycyclic aromatic compounds and heterocycles from the early 1900s through 2012. These data were collected using a variety of vapor pressure measurement techniques, from effusion to gas saturation to inclined-piston manometry. A brief overview of each measurement technique is given; these methods yield reproducible sublimation vapor pressure data for low volatility organic compounds such as polycyclic aromatic compounds and heterocycles. Several conclusions can be drawn from this literature survey, specifically that there remains a dearth of data on the sublimation thermodynamics (and fusion thermodynamics) of heteroatomic high molecular weight aromatic compounds, inhibiting a holistic understanding of the effect of specific heteroatoms and substituent position on the thermodynamics of these compounds. However, we can clearly see from the data that there are a variety of potential intermolecular interactions at work that generally tend to increase the enthalpy of sublimation and decrease the vapor pressure of a substituted polycyclic aromatic compound/polycyclic heterocycles versus its parent compound.
Chiral sulfur-containing 1,2-disubstituted ferrocenes

Abstract Enantiopure 1 -t- butylsulfinyl-2-subsituted ferrocenes were synthesized in reactions of (SR,1S,2R)-1-t-butylsulfinyl-2-lithioferrocene (11) with various electrophiles in good yields. (SR,1S,2R)-1-t-Butylsulfinyl-2-formylferrocene (19), prepared this way, underwent complete stereoselective addition reactions with Grignard reagents under chelation controlled conditions with titanium tetraisopropoxide. 1,4-Addition reactions of selected α,β-unsaturated esters with cuprate reagents gave mixtures of two diastereomers. The lack of stereoselectivity in these 1,4-addition reactions is due presumably to the remote reactive site (C-3′) and the flexibility of the side chain of the ester. A stereoselective cationic displacement reaction of (1S,2R,1′S)-1-(t-butylsulfonyl)-2-[α-(2-propenoyl)oxybenzyl]ferrocene (44) with 1-acetoxy-1,3-butadiene was found to produce (1S,2R,1′S)-1-(t-butylsulfonyl)-2-(5′-oxo-1′-phenyl-3′-pentenyl)ferrocene (45).
Quantum signatures of Solar System dynamics

Let ω(i) be period of rotation of the i-th planet around the Sun (or ωj(i) be period of rotation of j-th satellite around the i-th planet). From empirical observations it is known that within margins of experimental errors Σi niω(i) = 0 (or Σj njωj(i) = 0) for some integers ni (or nj ), different for different satellite systems. These conditions, known as resonance conditions, make uses of theories such as KAM difficult to implement. The resonances in Solar System are similar to those encountered in old quantum mechanics where applications of methods of celestial mechanics to atomic and molecular physics were highly successful. With such a successes, the birth of new quantum mechanics is difficult to understand. In short, the rationale for its birth lies in simplicity with which the same type of calculations can be done using methods of quantum mechanics capable of taking care of resonances. The solution of quantization puzzle was found by Heisenberg. In this paper new uses of Heisenberg?s ideas are found. When superimposed with the equivalence principle of general relativity, they lead to quantum mechanical treatment of observed resonances in the Solar System. To test correctness of theoretical predictions the number of allowed stable orbits for planets and for equatorial stable orbits of satellites of heavy planets is calculated resulting in good agreement with observational data. In addition, the paper briefl?y discusses quantum mechanical nature of rings of heavy planets and potential usefulness of the obtained results for cosmology.
Exploring the Specificity Pockets of Two Homologous SH3 Domains Using Structure-Based, Split-Pool Synthesis and Affinity-Based Selection

Split-pool synthesis was used to prepare large numbers of spatially-separated molecules and thereby to investigate the specificity pockets of similar SH3 domains found in the tyrosine kinases Src and Hck. By taking into account the structure of the Src SH3 domain complexed to a ligand containing non-peptide-binding elements, the molecules were designed to complement the topography of the protein's binding pocket. This procedure led to the discovery of ligands having greater affinity and enhanced selectivity for the Src SH3 domain. It also yielded non-natural ligands that bind selectively to the Hck SH3 domain. Insights gained from this strategy may facilitate the discovery of molecules useful for evaluating the cellular function of SH3 domain-containing proteins.
Control of the aqueous aldol addition under Claisen-Schmidt conditions

Abstract The influence of the addition of Lewis acid (zinc nitrate-hexahydrate) and Lewis base (N,N-dimethylaminoethanol) on the aqueous Claisen-Schmidt reaction was investigated. The results demonstrate the preferential activation of the aldol addition reaction by the zinc ion under either specific or general base conditions. A protocol has been developed which selectively produces aldol addition products under aqueous conditions.
Being funny is not enough: the influence of perceived humor and negative emotional reactions on brand attitudes

Humor is a common goal of marketing communications, yet humorous advertisements do not always improve consumer attitudes towards the advertised brand. By investigating a potential downside of attem...
The oxidative dehydrogenation of ethane over chlorine-promoted lithium-magnesium oxide catalysts

Abstract The addition of chlorine to a Li + MgO catalyst improves considerably the ethylene yield that may be attained during the oxidative dehydrogenation (OXD) of ethane. While operating at 650°C, Li + MgO catalysts, produced via a sol-gel method or by adding HCl to an unsintered Li + MgO catalyst, promoted a C2H6 conversion of 75–79% at a C2H4 selectivity of 70% after 50 hr on stream. Even after 250 hr the ethylene yield was 45%. Chlorine was slowly lost from the catalysts as a result of reaction with H 2 O, but the evidence indicates that the improved activity and selectivity is largely a result of heterogeneous rather than homogeneous chlorine-promoted reactions. Over the modified catalysts the rate of C 2 H 6 conversion was increased relative to the rate of C 2 H 4 conversion. The presence of chlorine in the solid significantly decreased the amount of C0 2 , a poison for the OXD reaction, that was taken up by the catalyst. Thus, C0 2 formed during the OXD of C2H6 may be less effective in poisoning the active centers on a chlorine-modified catalyst. The presence of chlorine also may alter the reactive forms of oxygen on the surface (e.g., O − ions) so that they are capable of activating the weaker CH bond in ethane, but are less effective in activating the stronger CH bond in ethylene. With respect to the oxidative coupling of CH 4 , these results demonstrate that at 650°C the primary step, which includes the activation of CH 4 and reactions involving CH 3 · radicals, is responsible mainly for the CO x products, not the subsequent oxidation of CH 4 and C 2 H 6 . This would be the case even at relatively high partial pressures of C 2 H 4 and C 2 H 6 .
Recurrent Loss of APOBEC3H Activity during Primate Evolution.

ABSTRACT Genes in the APOBEC3 family encode cytidine deaminases that provide a barrier against viral infection and retrotransposition. Of all the APOBEC3 genes in humans, APOBEC3H (A3H) is the most polymorphic: some genes encode stable and active A3H proteins, while others are unstable and poorly antiviral. Such variation in human A3H affects interactions with the lentiviral antagonist Vif, which counteracts A3H via proteasomal degradation. In order to broaden our understanding of A3H-Vif interactions, as well as its evolution in Old World monkeys, we characterized A3H variation within four African green monkey (AGM) subspecies. We found that A3H is highly polymorphic in AGMs and has lost antiviral activity in multiple Old World monkeys. This loss of function was partially related to protein expression levels but was also influenced by amino acid mutations in the N terminus. Moreover, we demonstrate that the evolution of A3H in the primate lineages leading to AGMs was not driven by Vif. Our work suggests that the activity of A3H is evolutionarily dynamic and may have a negative effect on host fitness, resulting in its recurrent loss in primates. IMPORTANCE Adaptation of viruses to their hosts is critical for viral transmission between different species. Previous studies had identified changes in a protein from the APOBEC3 family that influenced the species specificity of simian immunodeficiency viruses (SIVs) in African green monkeys. We studied the evolution of a related protein in the same system, APOBEC3H, which has experienced a loss of function in humans. This evolutionary approach revealed that recurrent loss of APOBEC3H activity has taken place during primate evolution, suggesting that APOBEC3H places a fitness cost on hosts. The variability of APOBEC3H activity between different primates highlights the differential selective pressures on the APOBEC3 gene family.
Gas Phase Cucurbit[n]uril Chemistry

The chemistry of cucurbit[n]urils is commanding increasing interest because of potential applications of these molecules in supramolecular structures; in drug encapsulation, protection, and delivery; and in sensitive new analytical assays. It is widely recognized that the binding properties of cucurbit[n]urils are sensitively dependent on solvents and counterions. Hence, gas phase studies, where neither solvent nor counterion species are present, are vital to gain fundamental understanding of cucuribituril complexes and to facilitate future applications. We use Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and ion mobility techniques to investigate the gas phase chemistry of cucurbit[n]urils and related species, addressing problems such as how trapping molecules inside the cucurbit[n]uril cavity affects the binding of cations on the rims, the mechanism of exchange of bound/trapped species, and the origin of the large pKa shifts that occur for trapped guests. This paper is a review of our work.
Catalytic Asymmetric Cyclocarbonylation of Nitrogen-Containing Enynes.

The asymmetric Pauson−Khand type cyclization of nitrogen-containing enynes using carbon monoxide and a catalytic amount of (EBTHI)TiMe2 was examined. The influence of the nitrogen substituent and the concentration of the catalyst on the enantioselectivity of this cyclization was explored, and it has been found that enynes with an octyl-, benzyl-, or allylamino group, positioned β to the alkyne and the olefin, are cyclized with a high degree of enantioselectivity. Substrates with either bulky and/or electron-withdrawing nitrogen substituents are converted to products in low to moderate enantioselectivity.
Chemical production from lignocellulosic biomass: thermochemical, sugar and carboxylate platforms

Abstract: Lignocellulose is abundant, inexpensive, and renewable. Further, it can replace fossil fuels as our primary source for chemicals and energy. To transition from fossil fuels to lignocellulose-based chemicals and fuels, an economically viable commercial biorefinery must be developed. This chapter reviews three major chemical platforms for a biorefinery. The thermochemical platform thermally degrades biomass into gaseous, liquid, and solid components. The sugar platform utilizes enzymes and/or chemicals to create sugars. The carboxylate platform ferments biomass into carboxylic acids/salts. The intermediate products of these three platforms serve as a ‘biocrude’ for the production of chemicals and fuels from lignocellulose.
OH radical reaction rate constants for polycyclic alkanes : effects of ring strain and consequences for estimation methods

Using a relative rate method, rate constants for the gas-phase reactions of the OH radical with trans-pinane [(1R, 2R)-2, 6, 6-trimethylbicyclo[3.1.1]heptane], tricyclene (1, 7, 7-trimethyltricyclo[2.2.1.02, 6]heptane), and quadricyclane (quadricyclo[2.2.1.02, 6.03, 5]heptane) of (1.34 ± 0.29) × 10−11 cm3 molecule−1 s−1, (2.86 ± 0.62) × 10−12 cm3 molecule−1 s−1 and (1.83 ± 0.41) × 10−12 cm3 molecule−1 s−1, respectively, have been determined at 296 ± 2 K. These rate constants are compared with values calculated from an empirical estimation method and used to refine this estimation technique for the calculation of OH radical reaction rate constants for polycyclic systems. © John Wiley & Sons, Inc.
Automated on-line column-switching high performance liquid chromatography isotope dilution tandem mass spectrometry method for the quantification of bisphenol A, bisphenol F, bisphenol S, and 11 other phenols in urine.

Human exposure to bisphenol A (BPA) is widespread. However, in recent years, bisphenol analogs such as bisphenol S (BPS) and bisphenol F (BPF) are replacing BPA in the production of some consumer products. Because human exposure to these alternative bisphenols may occur, biomonitoring of these bisphenol analogs is warranted. In the present study, we developed and validated a sensitive and selective method that uses on-line solid phase extraction coupled to high performance liquid chromatography-isotope dilution tandem mass spectrometry with peak focusing to measure BPA, BPF, BPS, and 11 other environmental phenols in urine. The method required a small amount of sample (100 µL) and minimal sample pretreatment. The limits of detection were 0.03 ng/mL (BPS), 0.06 ng/mL (BPF), 0.10 ng/mL (BPA), and ranged from 0.1 ng/mL to 1.0 ng/mL for the other 11 phenols. In 100 urine samples collected in 2009-2012 from a convenience group of anonymous adults in the United States, of the three bisphenols, we detected BPA at the highest frequency and median concentrations (95%, 0.72 ng/mL), followed by BPS (78%, 0.13 ng/mL) and BPF (55%, 0.08 ng/mL). This sensitive, rugged, and labor and cost-effective method could be used for the analysis of large number of samples for epidemiologic studies.
Palladium-Catalyzed Glycal Imidate Rearrangement: Formation of α- and β-N-Glycosyl Trichloroacetamides

A novel palladium(II)-catalyzed stereoselective synthesis of α- and β-N-glycosyl trichloroacetamides has been developed. The α- and β-selectivity at the anomeric carbon depends on the nature of the palladium−ligand catalyst. While the cationic palladium(II) promotes the α-selectivity, the neutral palladium(II) favors the β-selectivity.
Hypervelocity planets and transits around hypervelocity stars

The disruption of a binary star system by the massive black hole at the Galactic Centre, SgrA*, can lead to the capture of one star around SgrA* and the ejection of its companion as a hypervelocity star (HVS). We consider the possibility that these stars may have planets and study the dynamics of these planets. Using a direct N-body integration code, we simulated a large number of different binary orbits around SgrA*. For some orbital parameters, a planet is ejected at a high speed. In other instances, a HVS is ejected with one or more planets orbiting around it. In these cases, it may be possible to observe the planet as it transits the face of the star. A planet may also collide with its host star. In such cases the atmosphere of the star will be enriched with metals. In other cases, a planet is tidally disrupted by SgrA*, leading to a bright flare.
Organic iodine(V) compounds as terminal oxidants in iron(III) phthalocyanine catalyzed oxidation of alcohols

Abstract The pseudocyclic iodine(V) oxidants, such as esters of iodoxybenzoic acid (IBX-esters) and 2-iodylphenol ethers, can serve as stable and efficient sources of oxygen in catalytic oxidations, and their reactivity is similar to the commonly used thermally unstable and potentially explosive iodosylbenzene. In a specific example, primary or secondary benzylic alcohols are selectively oxidized by isopropyl IBX-ester in the presence of μ-oxo-(tetra-tert-butylphthalocyaninato)iron(III) (0.1 mol equiv) in dichloromethane at room temperature in 0.5–2 h to afford the respective carbonyl compounds in 100% conversion and preparative yields 91–95% after column chromatography.
Stable representation of sounds in the posterior striatum during flexible auditory decisions

The neuronal pathways that link sounds to rewarded actions remain elusive. For instance, it is unclear whether neurons in the posterior tail of the dorsal striatum (which receive direct input from the auditory system) mediate action selection, as other striatal circuits do. Here, we examine the role of posterior striatal neurons in auditory decisions in mice. We find that, in contrast to the anterior dorsal striatum, activation of the posterior striatum does not elicit systematic movement. However, activation of posterior striatal neurons during sound presentation in an auditory discrimination task biases the animals' choices, and transient inactivation of these neurons largely impairs sound discrimination. Moreover, the activity of these neurons during sound presentation reliably encodes stimulus features, but is only minimally influenced by the animals' choices. Our results suggest that posterior striatal neurons play an essential role in auditory decisions, and provides a stable representation of sounds during auditory tasks.
N-cadherin provides a cis and trans ligand for astrotactin that functions in glial-guided neuronal migration

Prior studies demonstrate that astrotactin (ASTN1) provides a neuronal receptor for glial-guided CNS migration. Here we report that ASTN1 binds N-cadherin (CDH2) and that the ASTN1:CDH2 interaction supports cell–cell adhesion. To test the function of ASTN1:CDH2 binding in glial-guided neuronal migration, we generated a conditional loss of Cdh2 in cerebellar granule cells and in glia. Granule cell migration was slowed in cerebellar slice cultures after a conditional loss of neuronal Cdh2, and more severe migration defects occurred after a conditional loss of glial Cdh2. Expression in granule cells of a mutant form of ASTN1 that does not bind CDH2 also slowed migration. Moreover, in vitro chimeras of granule cells and glia showed impaired neuron–glia attachment in the absence of glial, but not neuronal, Cdh2. Thus, cis and trans bindings of ASTN1 to neuronal and glial CDH2 form an asymmetric neuron–glial bridge complex that promotes glial-guided neuronal migration.
Ecological network metrics: opportunities for synthesis

Network ecology provides a systems basis for approaching ecological questions, such as factors that influence biological diversity, the role of particular species or particular traits in structuring ecosystems, and long-term ecological dynamics (e.g., stability). Whereas the introduction of network theory has enabled ecologists to quantify not only the degree, but also the architecture of ecological complexity, these advances have come at the cost of introducing new challenges, including new theoretical concepts and metrics, and increased data complexity and computational intensity. Synthesizing recent developments in the network ecology literature, we point to several potential solutions to these issues: integrating network metrics and their terminology across sub-disciplines; benchmarking new network algorithms and models to increase mechanistic understanding; and improving tools for sharing ecological network research, in particular “model” data provenance, to increase the reproducibility of network models and analyses. We propose that applying these solutions will aid in synthesizing ecological sub-disciplines and allied fields by improving the accessibility of network methods and models.
Semiparametric mixed-scale models using shared Bayesian forests.

This paper demonstrates the advantages of sharing information about unknown features of covariates across multiple model components in various nonparametric regression problems including multivariate, heteroscedastic, and semicontinuous responses. In this paper, we present a methodology which allows for information to be shared nonparametrically across various model components using Bayesian sum-of-tree models. Our simulation results demonstrate that sharing of information across related model components is often very beneficial, particularly in sparse high-dimensional problems in which variable selection must be conducted. We illustrate our methodology by analyzing medical expenditure data from the Medical Expenditure Panel Survey (MEPS). To facilitate the Bayesian nonparametric regression analysis, we develop two novel models for analyzing the MEPS data using Bayesian additive regression trees-a heteroskedastic log-normal hurdle model with a "shrink-toward-homoskedasticity" prior and a gamma hurdle model.
Cation Substitution in Defect Thiospinels: Structural and Magnetic Properties of GaV4-xMoxS8 (0≤x≤4)

A new family of nonstoichiometric materials, GaV4-xMoxS8 (0≤x≤4), has been prepared and characterized by high-resolution neutron powder diffraction, laboratory and synchrotron X-ray powder diffraction, thermogravimetry, and SQUID magnetometery. All materials adopt a cubic (F43m) structure at ambient temperature. The end-member phases GaV4S8 and GaMo4S8 exhibit a distortion to rhombohedral (R3m) symmetry at low temperatures. High-resolution powder neutron diffraction reveals that the phase transition is incomplete and that both cubic and rhombohedral phases coexist below ca. 40 K. Magnetic susceptibility data indicate that at low temperatures, the end-member phases undergo a transition to a ferromagnetic state in which the metal−metal exchange interactions within cubic B4S4 clusters are predominantly antiferromagnetic in origin. At intermediate compositions (1≤x≤3) a cubic structure persists to 4 K, and materials remain paramagnetic to this temperature. The suppression of the rhombohedral distortion may b...
A convenient synthesis of vinyl sulfides

tert-Alkyl sulfides, with an α-(1H-benzotriazol-1-yl) group 6 and 13, are readily prepared from N-[(aryl-thio)methyl]-1H-benzotriazoles 3 and N-(11), respectively, by reaction with BuLi and then with the appropriate electrophile. The tert-alkyl sulfides 6 and 13 are smoothly converted by BF3. OEt2 into vinyl sulfides 5, 7 or 12, respectively, in satisfactory yields.
The principle of nonperfect synchronization: recent developments

Publisher Summary This chapter describes the developments regarding the principle of nonperfect synchronization (PNS). The foundations of the PNS rest mainly on a relation between two fundamental concepts of physical organic chemistry: the concept of intrinsic barriers and the concept of transition state imbalances. The benefit of determining intrinsic barriers or intrinsic rate constants as the measures of chemical reactivity is that they can be used to describe the reactivity of an entire reaction family, irrespective of the thermodynamic driving force of a particular member of that family, and to make comparisons between different families. Because the observed trends in the intrinsic barriers can plausibly be explained by assuming that charge delocalization lags behind proton transfer, this may be taken as evidence for the existence of imbalance. The higher intrinsic rate constant for 1,1-dinitroethane compared to that for CH3NO2 is open to two interpretations, but both are related to the steric hindrance of the coplanarity of the two nitro groups in the anion. Even though the intrinsic barriers of the gas-phase reactions depend on the same factors as solution-phase proton transfers—such as resonance, polar, and polarizability effects—the electrostatic effects involving the proton-in-flight constitute an important additional factor.
New cationic olefin cyclization-pinacol reactions. Ring-expanding cyclopentane annulations that directly install useful functionality in the cyclopentane ring.

Two new tandem cationic olefin cyclization−pinacol reactions that provide cyclopentane-fused cycloalkanone products are described. Treatment of cis-1-[2-alkenyl-2-(triethylsiloxy)cycloalkyl]but-3-en-2-ol derivatives 21−24 with triflic anhydride at −78 °C affords cycloalkanones 31−34 in 54−90% yields with diastereoselectivities of typically >20:1. In this unusual transformation, the starting cycloalkanone is ring-expanded and fused to a 2-alkenylcyclopentane fragment. Reaction of cis-(2-siloxy-2-alkenylcycloalkyl)pyrrolidin-1-ylethanones 15−17 with triflic anhydride and 2,6-di-tert-butyl-4-methylpyridine (DTBMP) at −20 to +65 °C followed by hydrolysis of the intermediate iminium salts 64 with aqueous KHCO3 affords cycloalkanediones 46−48 in moderate yield and high diastereoselectivity (>20:1). These are the first examples of ring-expanding cyclopentane annulations that directly introduce a carbon side chain or carbonyl functionality at the cyclopentane C2 position. The high diastereoselectivities observed ...
Thermodynamic Properties of Molecular Borane Phosphines, Alane Amines, and Phosphine Alanes and the [BH4-][PH4+], [AlH4-][NH4+], and [AlH4-][PH4+] Salts for Chemical Hydrogen Storage Systems from ab Initio Electronic Structure Theory

The heats of formation for the molecules BH3PH3, BH2PH2, HBPH, AlH3NH3, AlH2NH2, HAlNH, AlH3PH3, AlH2PH2, HAlPH, AlH4-, PH3, PH4, and PH4+, as well as the diatomics BP, AlN, and AlP, have been calculated by using ab initio molecular orbital theory. The coupled cluster with single and double excitations and perturbative triples method (CCSD(T)) was employed for the total valence electronic energies. Correlation consistent basis sets were used, up through the augmented quadruple-ζ, to extrapolate to the complete basis set limit. Additional d core functions were used for Al and P. Core/valence, scalar relativistic, and spin−orbit corrections were included in an additive fashion to predict the atomization energies. Geometries were calculated at the CCSD(T) level up through at least aug-cc-pVTZ and frequencies were calculated at the CCSD(T)/aug-cc-pVDZ level. The heats of formation of the salts [BH4-][PH4+](s), [AlH4-][NH4+](s), and [AlH4-][PH4+](s) have been estimated by using an empirical expression for the ...
Modeling Marek's disease virus transmission: A framework for evaluating the impact of farming practices and evolution

Marek's disease virus (MDV) is a pathogen of chickens whose control has twice been undermined by pathogen evolution. Disease ecology is believed to be the main driver of this evolution, yet mathematical models of MDV disease ecology have never been confronted with data to test their reliability. Here, we develop a suite of MDV models that differ in the ecological mechanisms they include. We fit these models with maximum likelihood using iterated filtering in 'pomp' to data on MDV concentration in dust collected from two commercial broiler farms. We find that virus dynamics are influenced by between-flock variation in host susceptibility to virus, shedding rate from infectious birds, and cleanout efficiency. We also find evidence that virus is reintroduced to farms approximately once per month, but we do not find evidence that virus sanitization rates vary between flocks. Of the models that survive model selection, we find agreement between parameter estimates and previous experimental data, as well as agreement between field data and the predictions of these models. Using the set of surviving models, we explore how changes to farming practices are predicted to influence MDV-associated condemnation risk (production losses at slaughter). By quantitatively capturing the mechanisms of disease ecology, we have laid the groundwork to explore the future trajectory of virus evolution.
Discovering Conditionally Salient Features with Statistical Guarantees

The goal of feature selection is to identify important features that are relevant to explain an outcome variable. Most of the work in this domain has focused on identifying globally relevant features, which are features that are related to the outcome using evidence across the entire dataset. We study a more fine-grained statistical problem: conditional feature selection, where a feature may be relevant depending on the values of the other features. For example in genetic association studies, variant $A$ could be associated with the phenotype in the entire dataset, but conditioned on variant $B$ being present it might be independent of the phenotype. In this sense, variant $A$ is globally relevant, but conditioned on $B$ it is no longer locally relevant in that region of the feature space. We present a generalization of the knockoff procedure that performs conditional feature selection while controlling a generalization of the false discovery rate (FDR) to the conditional setting. By exploiting the feature/response model-free framework of the knockoffs, the quality of the statistical FDR guarantee is not degraded even when we perform conditional feature selections. We implement this method and present an algorithm that automatically partitions the feature space such that it enhances the differences between selected sets in different regions, and validate the statistical theoretical results with experiments.
The application of vinamidinium salts to the synthesis of 2,4-disubstituted thiophenes

The synthesis of 2,4-disubstituted thiophenes by the condensation of symmetrical vinamidinium salts with methyl thioglycolate has been accomplished for the first time. Simple experimental conditions were used to prepare seven different methyl 4-aryl-2-thiophenecarboxylates, three of which are new compounds.
Arylsulfur trifluorides: Improved method of synthesis and use as in situ deoxofluorination reagents

Abstract Building on recent results of Umemoto and Winter, an improved method of synthesis of arylsulfur trifluorides, including the excellent, new deoxofluorination reagent Fluolead, is hereby reported. The method utilizes Br2 and KF as oxidizing and fluorinating reagents for efficient, high yield conversion of aryl disulfides and mercaptans to arylsulfur trifluorides. It has also been shown that both Fluolead and mesitylsulfur trifluoride may be generated in acetonitrile and used as in situ deoxofluorination reagents for conversion of either aldehydes or ketones to their respective gem-difluoro compounds. An analysis of the probable mechanism of action, including computational efforts, allows postulation of a rationale for the highly variable reactivities of different arylsulfur trifluorides as deoxofluorination reagents.
1-methylcyclopropyl (MCP) ethers as protecting groups

Abstract Terminal 1,2- or 1,3-diol acetonides can be converted regioselectively into secondary 1-methylcyclopropyl (MCP) ether or primary triethylsilyl ethers under mild conditions. MCP ethers are stable to a variety of conditions and can be removed by treatment with NBS or DDQ.
Synthesis of Dihydrofurocoumarins via Palladium-Catalyzed Annulation of 1,3-Dienes by o-Iodoacetoxycoumarins

A variety of biologically interesting dihydrofurocoumarins have been synthesized in high yields by the palladium-catalyzed annulation of 1,3-dienes by o-iodoacetoxycoumarins. This reaction is very general and regioselective, and a wide variety of terminal, cyclic, and internal 1,3-dienes can be utilized.
Construction of the A-ring of cylindrospermopsin via an intramolecular oxazinone-N-oxide dipolar cycloaddition

Abstract The efficient synthesis of an A-ring synthon for the marine hepatatoxin cylindrospermopsin has been achieved. The key step features an intramolecular oxazinone N-oxide/alkene dipolar cycloaddition resulting in the establishment of the three contiguous stereogenic centers in the A-ring from one pre-existing stereogenic center in a single step.
A convenient biphasic process for the monosilylation of symmetrical 1,n-primary diols

Abstract A simple and mild biphasic process was developed for the selective protection of one of two chemically equivalent primary hydroxyl groups in 1,n-diols using t-butyldiphenyl silyl chloride in diisopropyl ethyl amine and dimethyl formamide.
Strongly fluorescent dipyrrinones - substituent effects

Bright yellow N,N'-carbonyl-bridged dipyrrinones (substituted 3H,5H-dipyrrolo[1,2-c:2′,1′-f]pyrimidine-3,5-diones) were synthesized by reaction of the parent dipyrrinone with carbonyldiimidazole. Their solutions in organic solvents fluoresced strongly, with fluorescent quantum yields (ϕF)0.32-0.92.
Unfortunate Moms and Unfortunate Children : Impact of the Nepali Civil War on Women's Stature and Intergenerational Health

This paper analyzes the long-term health impacts of Nepal's 1996-2006 civil conflict. It exploits the heterogeneity in conflict intensity across villages and birth cohorts to document long-term health and intergenerational impacts. The analysis finds that childhood exposure to conflict and, in particular, exposure starting in infancy, negatively impacts attained adult height. Each additional month of exposure decreases a women's adult height by 1.36 millimeters. The impacts are not limited to first-generation. The analysis also finds that a mother's exposure to conflict in her childhood is detrimental to her child's health. Mothers exposed to conflict during their childhood have more children and live in less wealthy households, likely reducing their ability to invest during their children’s critical period of physical development. The finding points to a potential trade-off between the quantity and quality of children. The paper uses information on monthly conflict incidents at the village level, which allows identifying identify the effects of exposure to conflict more accurately than prior studies.
HOW RESEARCH GOES ASTRAY: PATHS AND EQUILIBRIA

Some research disciplines persist for long periods despite contributing very little to our understanding of the world. In the presence of imperfect information about the quality of research, multiple equilibria can exist in which path dependence leads to disciplines going astray because researchers are incentivized to invest in low value lines of research. Research fields which have high social value are more likely to thrive, as are fields in which results are subject to evidence. Survivorship bias can lead to a distribution across disciplines in which weak disciplines have more talented researchers than do stronger disciplines. (JEL A11, A12, B40)
Some surfaces with non-polyhedral nef cones

Over algebraically closed fields of positive characteristic, C×C contains the family of curves cut out as graphs of iterates of the Frobenius morphism. Their self-intersection tends to negative infinity; hence C × C fails the bounded negativity conjecture in positive characteristic. This work arises as part of the broader question of whether C×C where C has genus ≥ 2 satisfies the bounded negativity conjecture in characteristic 0. When a surfaceX has a polyhedral nef cone, it automatically satisfies bounded negativity since all negative curves are extremal and polyhedral cones have finitely many extremal rays. We establish that this naive approach to bounded negativity fails for C×C. The original question remains open.