cssi/SciSciGPT-SciSciNet huggingface dataset:
The Exchange Rate : Why It Matters for Structural Transformation and Growth in Ethiopia

Ethiopia has achieved sustained high growth for more than a decade. At the same time, the country has been facing several economic challenges, including falling exports, chronic foreign currency shortages, as well as a slow pace of structural transformation. In recent years, the already overvalued birr has appreciated sharply in real terms, partly driven by the appreciation of the dollar, thereby making Ethiopia’s competitiveness and industrialization drive more difficult. In response to these challenges, this paper looks at the question of why the real exchange rate is a useful policy instrument. The analysis suggests that Ethiopia needs a more flexible exchange rate policy. A competitive or undervalued exchange rate is important in bringing about productivity-enhancing structural change. There is robust evidence that a real devaluation stimulates exports in general and manufacturing exports in particular, improves the trade and current account balances, and spurs economic growth. Currency undervaluation is a second-best policy intervention that can help offset some of the key constraints to manufacturing growth prevalent in low-income countries and speed up structural transformation. However, exchange rate adjustments need to take into account the increase in the cost of capital imports and debt burden.
California Climate Change Lawsuits: Can the Courts Help with Sea-Level Rise, and Who Knew What When?

Between 1900 and 2005, sea level along the extensive California coast rose seven inches (17.8 centimeters), and sea level rise there is still accelerating. Indeed, as the U.S. Global Change Research Program reported in 2014, the California coast faces a multitude of economic and ecological challenges as a result of climate change.Small wonder, then, that the State of California and several California communities — especially those in the San Francisco Bay area — have brought a series of lawsuits against some of the biggest sources of greenhouse gas (GHG) emissions, seeking both to slow the pace of climate change and to secure financial judgments that compensate for ongoing damages and help to finance adaptation measures. This short article summarizes what has been happening in the California municipalities three consolidated sea level rise-based climate change lawsuits. It concludes that, at the moment, judges in California disagree over whether these lawsuits are based on state tort law or federal common law, whether the lawsuits should be in state or federal court, and whether the lawsuits can proceed. To add to the fun, the SEC may become involved, raising questions about the plaintiffs' and defendants' relative climate change moral culpability.
Experimental and Computational Evidence for the Formation of Iminopersulfinic Acids

An experimental and computational study of the reactions of singlet oxygen with N-substituted sulfenamides is reported. Intermediates capable of epoxidizing norbornene were observed during the phot...
Synthesis of Substituted Pyridines via Regiocontrolled [4 + 2] Cycloadditions of Oximinosulfonates

Diels−Alder cycloadditions of oximinosulfonate 8 with a variety of 1,3-dienes proceed with regiochemistry opposite to that observed with conventional imino dienophiles, providing expeditious synthetic routes to substituted pyridines, tetrahydropyridines, and pyrrolines. The oximinosulfonate 8 is prepared in one convenient synthetic operation from Meldrum's acid and reacts with conjugated dienes at −78 °C in the presence of 2 equiv of dimethylaluminum chloride to afford [4 + 2] cycloadducts in good to excellent yield. Exposure of these cycloadducts to the action of NaOMe and N-chlorosuccinimide in methanol−THF at room temperature then produces substituted pyridines. The utility of this new two-step annulation protocol is demonstrated in total syntheses of the pyridine alkaloids fusaric acid and (S)-(+)-fusarinolic acid. Heating the [4 + 2] cycloadducts derived from 8 in a mixture of acetonitrile and pH 7 phosphate buffer induces an unusual Stieglitz-type rearrangement leading to the formation of interestin...
Modular preprocessing pipelines can reintroduce artifacts into fMRI data

The preprocessing pipelines typically used in both task and resting-state functional magnetic resonance imaging (rs-fMRI) analysis are modular in nature: They are composed of a number of separate filtering/regression steps, including removal of head motion covariates and band-pass filtering, performed sequentially and in a flexible order. In this article, we illustrate the shortcomings of this approach, as we show how later preprocessing steps can reintroduce artifacts previously removed from the data in prior preprocessing steps. We show that each regression step is a geometric projection of data onto a subspace, and that performing a sequence of projections can move the data into subspaces no longer orthogonal to those previously removed, reintroducing signal related to nuisance covariates. Thus, linear filtering operations are not commutative, and the order in which the preprocessing steps are performed is critical. These issues can arise in practice when any combination of standard preprocessing steps including motion regression, scrubbing, component-based correction, physiological correction, global signal regression, and temporal filtering are performed sequentially. In this work, we focus primarily on rs-fMRI. We illustrate the problem both theoretically and empirically through application to a test-retest rs-fMRI data set, and suggest remedies. These include (a) combining all steps into a single linear filter, or (b) sequential orthogonalization of covariates/linear filters performed in series.
An efficient synthesis of 3,4-dihydropyridone via a tandem olefin isomerization–ring-closing metathesis reaction

Novel 3,4-dihydropyridones were efficiently prepared via a tandem olefin isomerization–ring-closing metathesis reaction catalyzed by the second-generation Grubbs catalyst. The products were further functionalized at the 5-position, providing an interesting structural motif to be evaluated in medicinal chemistry.
The preparation of 3-substituted 1,2-benzisothiazole 1,1-dioxides from lithiated intermediates or grignard reagents and methyl 2-(aminosulfonyl)benzoate

A polylithiated β-ketoester, β-diketone, or β-ketoamide was condensed-cyclized with lithiated methyl 2-(aminosulfonyl)benzoate, to afford new 3-substituted 1,2-benzisothiazole 1,1-dioxides. Some Grignard or organolithium reagents were also condensed-cyclized with methyl 2-(aminosulfonyl)benzoate to give 3-substituted 1,2-benzisothiazole 1,1-dioxides.
Synthesis of novel porphyrin chromophores from nitroarenes: Further applications of the Barton-Zard pyrrole condensation

Abstract Porphyrins with fused nitronaphthalene and benzothiadiazole subunits have been synthesized by the “2 + 2” and “3 + 1” methodologies; the key pyrrolic intermediates were prepared by the base catalyzed condensation of dinitronaphthalenes or 4-nitro-2,1,3-benzothiadiazole with isocyanoacetates.
Synthesis of phenanthro[2,3-h]isoquinoline and phenanthro[3,2-h]isoquinoline

The suspected environmental contaminants phenanthro[2,3-h]isoquinoline 12 and phenanthro[3,2-h]isoquinoline 11 were synthesized in four steps from a common intermediate 1,4-phenanthroquinone 3, using a Diels-Alder reaction.
In vivo effects of temperature on the heart and pyloric rhythms in the crab Cancer borealis.

ABSTRACT The heart and pyloric rhythms of crustaceans have been studied separately and extensively over many years. Local and hormonal neuromodulation and sensory inputs into these central pattern generator circuits play a significant role in an animal9s response to perturbations, but are usually lost or removed during in vitro studies. To examine simultaneously the in vivo motor output of the crustacean heart and pyloric rhythms, we used photoplethysmography. In the population measured ( n =49), the heart rhythm frequency ranged from 0.3 to 2.3 Hz. The pyloric rhythm varied from 0.2 to 1.6 Hz. We observed a weak correlation between the frequencies of the heart and pyloric rhythms. During multiple hour-long recordings, many animals held at a controlled temperature showed strong inhibitory bouts in which the heart decreased in frequency or become quiescent and the pyloric rhythm decreased in frequency. We measured the simultaneous responses of the rhythms to temperature ramps by heating or cooling the saline bath while recording both the heart and pyloric muscle movements. Q 10 , critical temperature (temperature at which muscle function is compromised) and changes in frequency were calculated for each of the rhythms tested. The heart rhythm was more robust to high temperature than the pyloric rhythm.
Phosphine-Mediated [4 + 2] Annulation of Bis(enones): A Lewis Base Catalyzed “Mock Diels−Alder” Reaction

Lewis-base-catalyzed cycloisomerization of bis(enones) to decalins has been demonstrated as an alternative to the traditional Lewis acid catalyzed Diels−Alder cycloaddition. In this process, a trialkylphosphine mediates both bond formation steps in two distinct catalytic cycles. The single-pot operation generates two carbon−carbon bonds and up to five contiguous stereocenters in one step, starting from achiral, aliphatic substrates; eight examples are provided.
Reactions of TFDA with ketones. synthesis of difluoromethyl 2,2-difluorocyclopropyl ethers.

The sequential reaction of 2 equiv of difluorocarbene (generated from trimethylsilyl fluorosulfonyldifluoroacetate (TFDA) by treatment with catalytic fluoride ion) with a series of electron-rich aromatic ketones and α,β-unsaturated ketones leads to the formation of difluoromethyl 2,2-difluorocyclopropyl ethers in good yield.
Oxidative cyclization of N-alkyl-o-methyl-arenesulfonamides to biologically important saccharin derivatives

Abstract Various biologically important saccharin skeletons and their N-alkyl derivatives have been efficiently prepared by chromium(VI) oxide catalyzed H5IO6 oxidation of N-alkyl-o-methyl-arenesulfonamides in acetonitrile. N-tert-Butyl saccharin skeletons were easily prepared by H5IO6–CrO3 oxidation of N-tert-butyl-o-methyl arenesulfonamides in the presence of acetic anhydride. The method that furnished the novel fluoro and trifluoromethyl substituted saccharin skeletons is characterized by two steps, a simple work-up procedure, a single purification and good overall yields from substituted toluene derivatives.
Comparative multi-scale hierarchical structure of the tail, plantaris, and Achilles tendons in the rat.

Rodent tendons are widely used to study human pathologies such as tendinopathy and repair, and to address fundamental physiological questions about development, growth, and remodeling. However, how the gross morphology and multi-scale hierarchical structure of rat tendons, such as the tail, plantaris, and Achilles tendons, compare with that of human tendons are unknown. In addition, there remains disagreement about terminology and definitions. Specifically, the definitions of fascicle and fiber are often dependent on diameter sizes, not their characteristic features, and these definitions impair the ability to compare hierarchical structure across species, where the sizes of the fiber and fascicle may change with animal size and tendon function. Thus, the objective of the study was to select a single species that is commonly used for tendon research (rat) and tendons with varying mechanical functions (tail, plantaris, Achilles) to evaluate the hierarchical structure at multiple length scales using histology, SEM, and confocal imaging. With the exception of the specialized rat tail tendon, we confirmed that in rat tendons there are no fascicles and the fiber is the largest subunit. In addition, we provided a structurally based definition of a fiber as a bundle of collagen fibrils that is surrounded by elongated cells, and this definition was supported by both histologically processed and unprocessed samples. In all rat tendons studied, the fiber diameters were consistently between 10 and 50 μm, and this diameter range appears to be conserved across larger species. Specific recommendations were made highlighting the strengths and limitations of each rat tendon as a research model. Understanding the hierarchical structure of tendon can advance the design and interpretation of experiments and development of tissue-engineered constructs.
Enantioselective rhodium(I)-triethylamine catalyzed addition of potassium isopropenyl trifluoroborate to enones

A general process is reported for the highly enantioselective 1,4-addition of isopropenyl trifluoroborate to cyclic enones under catalysis by a chiral Rh(I) complex and triethylamine at room temperature.
Pb3F5NO3, a Cationic Layered Material for Anion-Exchange

Our research involves the development of new cationic materials for anion-based applications. We report the solvothermal synthesis and characterization of Pb3F5NO3, a new layered lead fluoride material that, unlike the majority of layered and open-framework materials, is cationic in charge. The structure consists of polyhedral lead centers connected by doubly and triply bridging fluoride groups. We quantitatively exchanged the interlamellar nitrate groups of Pb3F5NO3 for dichromate, under ambient aqueous conditions. Nuclear magnetic resonance and UV−vis spectroscopy show the reaction proceeds to 61.0% completion in several days. The material is also stable to 450 °C, which is vastly superior to organic resins that are still the standard for anion-exchange. The presence of extraframework anions also opens up other potentially unique anion-based properties, such as new catalytic reactions, anion intercalation, or growth of anionic clusters within the void spaces of the cationic material.
Fold-Change Detection of NF-κB at Target Genes with Different Transcript Outputs.

Abstract The transcription factor nuclear factor (NF)-κB promotes inflammatory and stress-responsive gene transcription across a range of cell types in response to the cytokine tumor necrosis factor (TNF). Although NF-κB signaling exhibits significant variability across single cells, some target genes supporting high levels of TNF-inducible transcription exhibit fold-change detection of NF-κB, which may buffer against stochastic variation in signaling molecules. It is unknown whether fold-change detection is maintained at NF-κB target genes with low levels of TNF-inducible transcription, for which stochastic promoter events may be more pronounced. Here, we used a microfluidic cell-trapping device to measure how TNF-induced activation of NF-κB controls transcription in single Jurkat T cells at the promoters of integrated HIV and the endogenous cytokine gene IL6, which produce only a few transcripts per cell. We tracked TNF-stimulated NF-κB RelA nuclear translocation by live-cell imaging and then quantified transcript number by RNA FISH in the same cell. We found that TNF-induced transcript abundance at 2 h for low- and high-abundance target genes correlates with similar strength with the fold change in nuclear NF-κB. A computational model of TNF-NF-κB signaling, which implements fold-change detection from competition for binding to κB motifs, could reproduce fold-change detection across the experimentally measured range of transcript outputs. However, multiple model parameters affecting transcription had to be simultaneously varied across promoters to maintain fold-change detection while also matching other trends in the single-cell data for low-abundance transcripts. Our results suggest that cells use multiple biological mechanisms to tune transcriptional output while maintaining robustness of NF-κB fold-change detection.
A new method for the synthesis of substituted indeno[1,2-b]thiophene with subsequent ring expansion to form substituted thieno[3,2-c]quinoline

2-Phenacylindan-1,3-dione (3) was treated with Lawesson's reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) to form 2-phenyl-4H-indeno[1,2-b]thiophene-4-one (4). Compound 4 was subsequently reacted with hydroxyl amine to form the oxime (5), which, upon treatment with polyphosphoric acid, underwent ring expansion (Beckmann rearrangement) to give 2-phenylthieno[3,2-c]quinoline-4(5H)one.
Preparation of 1,3-dienyl organotrifluoroborates and their Diels-Alder/cross-coupling reactions

Abstract 2-BF3-substituted 1,3-butadienes with potassium and tetrabutyl ammonium counterions have been prepared in gram quantities from chloroprene via a simple synthetic procedure. The potassium salt of this new main group element substituted diene has been characterized by 1H, 13C, 11B, and 19F NMR and the tetra n-butyl ammonium salt was also characterized by X-ray crystallography. Diels–Alder reactions of these dienes with dienophiles such as ethyl acrylate, methyl vinyl ketone, and N-phenylmaleimide are reported as well as subsequent Pd-catalyzed cross-coupling reactions of those Diels–Alder adducts. 4-Phenyl-2-BF3-substituted 1,3-diene was prepared by magnesium–halogen exchange from the corresponding 2-bromo and iodo dienes. The 4-phenyl-2-bromo-1,3-butadiene was also characterized by X-ray crystallography. 4-Phenyl-2-BF3-1,3-butadiene was used in Diels–Alder/cross-coupling reactions and the product of a Diels–Alder reaction with N-phenylmaleimide followed by cross-coupling with 4-bromo-benzonitrile was also characterized by X-ray crystallography.
Modeling Epistemology: Examples and Analysis in Computational Philosophy of Science

What structure of scientific communication and cooperation, between what kinds of investigators, is best positioned to lead us to the truth? Against an outline of standard philosophical characteristics and a recent turn to social epistemology, this paper surveys highlights within two strands of computational philosophy of science that attempt to work toward an answer to this question. Both strands emerge from abstract rational choice theory and the analytic tradition in philosophy of science rather than postmodern sociology of science. The first strand of computational research models the effect of communicative networks within groups, with conclusions regarding the potential benefit of limited communication. The second strand models the potential benefits of cognitive diversity within groups. Examples from each strand of research are used in analyzing what makes modeling of this sort both promising and distinctly philosophical, but are also used to emphasize possibilities for failure and inherent limitations as well.
Deep Learning based multi-omics integration robustly predicts survival in liver cancer

Identifying robust survival subgroups of hepatocellular carcinoma (HCC) will significantly improve patient care. Currently, endeavor of integrating multi-omics data to explicitly predict HCC survival from multiple patient cohorts is lacking. To fill this gap, we present a deep learning (DL)-based model on HCC that robustly differentiates survival subpopulations of patients in six cohorts. We built the DL-based, survival-sensitive model on 360 HCC patients' data using RNA sequencing (RNA-Seq), miRNA sequencing (miRNA-Seq), and methylation data from The Cancer Genome Atlas (TCGA), which predicts prognosis as good as an alternative model where genomics and clinical data are both considered. This DL-based model provides two optimal subgroups of patients with significant survival differences (P = 7.13e-6) and good model fitness [concordance index (C-index) = 0.68]. More aggressive subtype is associated with frequent TP53 inactivation mutations, higher expression of stemness markers (KRT19 and EPCAM) and tumor marker BIRC5, and activated Wnt and Akt signaling pathways. We validated this multi-omics model on five external datasets of various omics types: LIRI-JP cohort (n = 230, C-index = 0.75), NCI cohort (n = 221, C-index = 0.67), Chinese cohort (n = 166, C-index = 0.69), E-TABM-36 cohort (n = 40, C-index = 0.77), and Hawaiian cohort (n = 27, C-index = 0.82). This is the first study to employ DL to identify multi-omics features linked to the differential survival of patients with HCC. Given its robustness over multiple cohorts, we expect this workflow to be useful at predicting HCC prognosis prediction. Clin Cancer Res; 24(6); 1248-59. ©2017 AACR.
The SAR of UK-78,282 : A novel blocker of human T cell Kv1.3 potassium channels

Abstract UK-78,282 was identified in a human T cell 86Rb efflux high-throughput screen of our compound libraries. This compound was found to be a potent and selective blocker of human T cell voltage-gated K+ channels and to inhibit T cell activation. The SAR around UK-78,282 and a general pharmacophore hypothesis are presented in this communication.
An RNAi screen in human cell lines reveals conserved DNA damage repair pathways that mitigate formaldehyde sensitivity

Formaldehyde is a ubiquitous DNA damaging agent, with human exposures occurring from both exogenous and endogenous sources. Formaldehyde exposure can result in multiple types of DNA damage, including DNA-protein crosslinks and thus, is representative of other exposures that induce DNA-protein crosslinks such as cigarette smoke, automobile exhaust, wood smoke, metals, ionizing radiation, and certain chemotherapeutics. Our objective in this study was to identify the genes necessary to mitigate formaldehyde toxicity following chronic exposure in human cells. We used siRNAs that targeted 320 genes representing all major human DNA repair and damage response pathways, in order to assess cell proliferation following siRNA depletion and subsequent formaldehyde treatment. Three unrelated human cell lines frequently used in genotoxicity studies (SW480, U-2 OS and GM00639) were used to identify common pathways involved in mitigating formaldehyde sensitivity. Although there were gene-specific differences among the cell lines, four inter-related cellular pathways were determined to mitigate formaldehyde toxicity: homologous recombination, DNA double-strand break repair, ionizing radiation response and DNA replication. Additional insight into cell line-specific response patterns was obtained by using a combination of exome sequencing and Cancer Cell Line Encyclopedia genomic data. The results of this DNA damage repair pathway-focused siRNA screen for formaldehyde toxicity in human cells provide a foundation for detailed mechanistic analyses of pathway-specific involvement in the response to environmentally-induced DNA-protein crosslinks and, more broadly, genotoxicity studies using human and other mammalian cell lines.
Isomerization, autoxidation and epimerization for the introduction of C-1 to C-5 functionality into the taxane ABC ring system

Abstract Treatment of 2-ketotax-3-enes with t-BuOK/t-BuOH/THF/65°C results in isomerization of the double bond into the 4,5-position and a trans-B/C ring fusion. Subsequent exposure to t-BuOK/THF/O2/P(OEt)3 introduces the C-1-hydroxyl group.
Synthesis of l,l-puromycin

Abstract l , l -Puromycin, a diastereomer of the natural peptidyl nucleoside antibiotic puromycin, has been synthesized from l -xylose in 13 steps.
Structure, bonding, and asymmetric induction in (R,R)-2,3-dimethoxy-1,4-bis(dimethylamino)butane complexes with organolithium compounds: A semiempirical computational study

Abstract Semiempirical PM3 calculations were performed on several organolithium complexes with (R,R)-2,3-dimethoxy-1,4-bis(dimethylamino)butane. The calculations showed that the ligand binding mode is dependent on the aggregation state of the organolithium, and may bind via the nitrogen atoms, oxygen atoms, or both. The complex with t-butyllithium exists as a monomer, while the complexes with several other organolithium compounds exist primarily as dimers. Complexes between the various chelated forms of butyllithium and propanal were examined in order to better understand the mechanism of asymmetric induction.
A dynamical model for the low efficiency of induced pluripotent stem cell reprogramming

In the past decade, researchers have been able to obtain pluripotent stem cells directly from an organism's differentiated cells through a process called cell reprogramming. This opens the way to potentially groundbreaking applications in regenerative and personalized medicine, in which ill patients could use self-derived induced pluripotent stem (iPS) cells where needed. While the process of reprogramming has been shown to be possible, its efficiency remains so low after almost ten years since its conception as to render its applicability limited to laboratory research. In this paper, we study a mathematical model of the core transcriptional circuitry among a set of key transcription factors, which is thought to determine the switch among pluripotent and early differentiated cell types. By employing standard tools from dynamical systems theory, we analyze the effects on the system's dynamics of overexpressing the core factors, which is what is performed during the reprogramming process. We demonstrate that the structure of the system is such that it can render the switch from an initial stable steady state (differentiated cell type) to the desired stable steady state (pluripotent cell type) highly unlikely. This finding provides insights into a possible reason for the low efficiency of current reprogramming approaches. We also suggest a strategy for improving the reprogramming process that employs simultaneous overexpression of one transcription factor along with enhanced degradation of another.
The synthesis of 2-azido C-glycosyl sugars

Abstract 2-Azido C-glycosyl sugars can be prepared by the Lewis acid catalyzed addition of alkyl silanes to the nitrate glycosides of 2-azido sugars. The products are ozonized to the corresponding aldehydes for further elaboration.
The formation of bilayered nickel-iron, cadmium-iron and cadmium—silver hexacyanoferrates by an electrochemically driven insertion—substitution mechanism

Upon cyclic oxidation and reduction of a parent metal hexacyanoferrate, metal ions from the electrolyte solution can be driven into interstitial positions of the zeolitic structure of the metal hexacyanoferrate. Whereas alkali metal ions are stable on these sites, some other metal ions undergo a substitution reaction with the N-coordinated metal ions, since the latter are only weakly bonded. This results in the formation of a layer of a daughter metal hexacyanoferrate covering the parent metal hexacyanoferrate. A bilayered structure is formed which can be identified by its behaviour in cyclic voltammetry. There is no indication that the electron and ion transfer through the interface of the two layers is hindered. From this and the growth mechanism it is probable that the daughter hexacyanoferrate will form an epitaxial layer on top of the parent hexacyanoferrate, provided that the two hexacyanoferrates do not differ too much in their lattice parameters. Experimental results, for which abrasive stripping voltammetry was used, are reported for a nickel hexacyanoferrate layer on Prussian blue, for a cadmium hexacyanoferrate layer on Prussian blue, and for a cadmium hexacyanoferrate layer on silver hexacyanoferrate.
Facile selective cleavage of a myo-inositol trans-isopropylidene acetal in the presence of a cis-isopropylidene acetal

Abstract 1,2:4,5-Di-O-isopropylidene myo-inositol acetals were selectively deprotected at the 4,5-trans position using Amberlite-120 (H+) resin in CHCl3/MeOH at room temperature over 24–48 h to afford the corresponding cis-1,2-O-isopropylidene myo-inositol acetals in near quantitative yield.
Oxidation of substituted pyridines by dimethyldioxirane: kinetics and solvent effects

Abstract The oxidation of a series of substituted pyridines by dimethyldioxirane ( 1 ) produced the expected N -oxides in quantitative yields. The second order rate constants ( k 2 ) for the oxidation of a series of substituted pyridines ( 2a – g ) by dimethyldioxirane were determined in dried acetone at 23 °C. An excellent correlation with Hammett sigma values was found ( ρ = −2.91, r = 0.995). Kinetic studies for the oxidation of 4-trifluoromethylpyridine by 1 were carried out in the following dried solvent systems: acetone ( k 2 = 0.017 M −1 s −1 ), carbon tetrachloride/acetone (7:3; k 2 = 0.014 M −1 s −1 ), acetonitrile/acetone (7:3; k 2 = 0.047 M −1 s −1 ), and methanol/acetone (7:3; k 2 = 0.68 M −1 s −1 ). Kinetic studies of the oxidation of pyridine by 1 versus mole fraction of water in acetone [ k 2 = 0.78 M −1 s −1 ( χ = 0) to k 2 = 11.1 M −1 s −1 ( χ = 0.52)] were carried out. The results showed the reaction to be very sensitive to protic, polar solvents.
(Dichloroiodo)benzene and lead(II) thiocyanate as an efficient reagent combination for stereoselective 1,2-dithiocyanation of alkynes

Abstract An efficient stereoselective 1,2-dithiocyanation of various alkynes has been accomplished by using a reagent combination of (dichloroiodo)benzene and lead(II) thiocyanate in dichloromethane at 0–5°C.
Use of acid fluorides increases the scope of the reductive acylation of esters.

The use of acyl fluorides in the Rychnovsky reductive acylation of esters allows a variety of esters to be converted to their corresponding α-acyloxy ethers in good to excellent yields, without the need to sacrifice an extra equiv of carboxylic acid functionality.
Solvent Effects on Fluorine Shielding in Fluorobenzene

Computer simulations of fluorobenzene dissolved in ten organic liquids and water have been used to explore the origins of solvent-induced changes in the fluorine chemical shielding parameter when this molecule is transferred from the gas phase to a solvent. Relying on recent theoretical calculations, it is demonstrated that short-range (van der Waals) interactions between the fluorine nucleus and solvent molecules are the predominant source of shielding parameter changes. Electric fields created by the solvent also have a detectable effect on shielding. The approaches used to estimate the van der Waals and electrostatic contributions inherently contain adjustable parameters and, if these are optimized, excellent agreement between calculated shielding effects and those found experimentally is obtained. The treatment used leads to reliable estimates of solvent-induced changes for solvents as diverse as water, hexane, and methylene iodide.
GSTR: Secure multi-hop message dissemination in connected vehicles using social trust model

Abstract The emergence of connected vehicles paradigm has made secure communication a key concern amongst the connected vehicles. Communication between the vehicles and Road Side Units (RSUs) is critical to disseminate message among the vehicles. We focus on secure message transmission in connected vehicles using multi-hop social networks environment to deliver the message with varying trustworthiness. We proposed a Geographic Social Trust Routing (GSTR) approach; messages are propagated using multiple hops and by considering the various available users in the vehicular network. GSTR is proposed in an application perspective with an assumption that the users are socially connected. The users are selected based on trustworthiness as defined by social connectivity. The route to send a message is calculated based on the highest trust level of each node by using the node's social network connections along the path in the network. GSTR determines the shortest route using the trusted nodes along the route for message dissemination. GSTR is made delay tolerant by introducing message storage in the cloud if a trustworthy node is unavailable to deliver the message. We compared the proposed approach with Geographic and Traffic Load based Routing (GTLR), Greedy Perimeter Stateless Routing (GPSR), Trust-based GPSR (T-GPSR). The performance results obtained show that GSTR ensures efficient resource utilization, lower packet losses at high vehicle densities.
A camphor-derived vinylsulfonium salt as a reagent for a cycloannulation

Abstract A chiral, non-racemic vinylsulfonium salt 6 was prepared from camphorquinone in seven steps and reacted with indole-2-carboxaldehyde to give a tricyclic azido alcohol 2 in a 35% yield and 43% e.e. and a 40% recovery of the chiral sulfide.
Characterizing highly dynamic conformational states: The transcription bubble in RNAP-promoter open complex as an example.

Bio-macromolecules carry out complicated functions through structural changes. To understand their mechanism of action, the structure of each step has to be characterized. While classical structural biology techniques allow the characterization of a few "structural snapshots" along the enzymatic cycle (usually of stable conformations), they do not cover all (and often fast interconverting) structures in the ensemble, where each may play an important functional role. Recently, several groups have demonstrated that structures of different conformations in solution could be solved by measuring multiple distances between different pairs of residues using single-molecule Forster resonance energy transfer (smFRET) and using them as constrains for hybrid/integrative structural modeling. However, this approach is limited in cases where the conformational dynamics is faster than the technique's temporal resolution. In this study, we combine existing tools that elucidate sub-millisecond conformational dynamics together with hybrid/integrative structural modeling to study the conformational states of the transcription bubble in the bacterial RNA polymerase-promoter open complex (RPo). We measured microsecond alternating laser excitation-smFRET of differently labeled lacCONS promoter dsDNA constructs. We used a combination of burst variance analysis, photon-by-photon hidden Markov modeling, and the FRET-restrained positioning and screening approach to identify two conformational states for RPo. The experimentally derived distances of one conformational state match the known crystal structure of bacterial RPo. The experimentally derived distances of the other conformational state have characteristics of a scrunched RPo. These findings support the hypothesis that sub-millisecond dynamics in the transcription bubble are responsible for transcription start site selection.
An Ab initio Study of the P-C Bond Rotation in Phosphoryl- and Thiophosphoryl-Stabilized Carbanions: Five- and Six-Membered Heterocycles

The potential energy surfaces for the P−C bond rotation in the 2-oxo- and 2-thioxo-2-methyl-1,3,2-diazaphosphorinane and -1,3,2-diazaphospholidine anions have been investigated at MP4(SDQ)/6-31+G*//HF/6-31+G* + ZPE. Four stationary points have been found for the six-membered ring species. The lowest energy structures exhibit a completely or nearly planar carbanion with its substituents parallel to the PX axis (X = O, S). The transition state (TS) structures have a strongly pyramidalized carbanion in which the lone pair (LP) is approximately perpendicular to the PX bond. Isodesmic equations, bond length comparisons, and orbital interactions indicate a superior ground state (GS) stabilization of the thioxo derivative and a favorable TS stabilization of the oxo species. Both effects cooperate to furnish the computationally and experimentally observed higher (ca. 2.5 kcal/mol in both cases) P−C rotational barrier for the 2-thioxo-1,3,2-diazaphosphorinane based anions. Coordination of a lithium cation to the c...
Technical Note—Assortment Optimization with Small Consideration Sets

In the paper “Assortment Optimization with Consideration Sets,” we study a customer choice model that captures purchasing behavior when there is a limit on the number of times that a customer will ...
Spin 2 operators in holographic 4d $\mathcal N=2$ SCFTs

A broad class of holographic duals for 4d $$ \mathcal{N}=2 $$ SCFTs is based on the general half-BPS AdS5 solutions to M-theory constructed by Lin, Lunin and Maldacena, and their Kaluza-Klein reductions to Type IIA. We derive the equations governing spin 2 fluctuations around these solutions. The resulting partial differential equations admit families of universal solutions which are constructed entirely out of the generic data characterizing the background. This implies the existence of families of spin 2 operators in the dual SCFTs, in short superconformal multiplets which we identify.
Rational explanation for rule-of-thumb practices in asset allocation

Naive asset allocation and other ad-hoc techniques are commonly practiced by fund managers in the industry. Such strategies, however, are deemed mean-variance (MV) sub-optimal according to modern p...
Decision Usefulness and Accelerated Filing Deadlines

In this study we examine the impact of the Securities and Exchange Commission's (SEC) decision to accelerate the filing of 10-Ks. The SEC argued that the accelerated deadline would increase the relevance of the disclosures, making the reports more useful. Opponents countered that the accelerated deadline would decrease the representational faithfulness of the disclosures, especially for smaller firms. We document a significant decrease in the 10-K market reaction for smaller firms as they accelerate from 90 to 75 days. For larger firms we find no significant change in the market reaction from 90 to 75 days. However, as these larger firms accelerate their 10-K deadline to 60 days, we find a significant increase in the market reaction. We also examine changes in reporting quality, shifts in information content, and changes in 10-K filing order and clustering and find results that are consistent with accelerated filing having significant impacts on representational faithfulness and relevance.
Sonographic appearance of the late gestation equine fetal intestine.

Abstract Variable gestation length in the mare poses a challenge for determination of fetal readiness for birth. The objectives of this study were to describe sonographic characteristics of the fetal GI tract in the late gestation mare and identify changes that occur with progressing fetal maturity. Based on these characteristics, a grading scale modeled after the existing human and canine scoring system was developed. Weekly sonographic examination of the fetus by one observer beginning 2–3 weeks prior to a calculated due date of 330 days was performed. Fetal assessment included; presence of stomach rugae, bowel segment definition (uniform echogenic, some defined, clearly defined), bowel segment dilation (none, segmental dilation), intestinal contents (none, mixed echogenicity) and peristalsis (none, occasional, every 3 s, continuous). Based on these characteristics a phase was assigned to the GI tract (1–5). Phase 1 was defined as a uniform echogenic grey area caudal to the diaphragm. The differentiation of Phase 2–5 was based primarily on the frequency of peristalsis, with Phase 2 exhibiting no peristalsis, Phase 3 exhibiting occasional peristalsis, Phase 4 exhibiting peristalsis every 3 s and Phase 5 exhibiting continuous peristalsis. Only data from mares with a normal parturition and healthy foals were included in the statistics (N = 10). Associations amongst sonographic fetal GI characteristics and days prepartum were validated using a simulation-based bootstrap approach with 1000 replicates using Stata 14. Stomach rugae, peristalsis, intestinal contents, tail head relaxation and udder development were all highly correlated with days prepartum. Using a multiple linear regression model, tail head relaxation and peristalsis predicted days prepartum with a 95% CI ± 6 days. The same model predicted days prepartum with a 95% CI ± 4 days when day of gestation, tail head relaxation and peristalsis were included as variables. Based on these findings, characterization of the fetal GI tract could provide valuable information concerning the maturity of the equine fetus. Further studies are needed comparing high risk mares to normal mares before this information could be used with confidence in the clinical setting.
Efficient Beam Alignment in Millimeter Wave Systems Using Contextual Bandits

In this paper, we investigate the problem of beam alignment in millimeter wave (mmWave) systems, and design an optimal algorithm to reduce the overhead. Specifically, due to directional communications, the transmitter and receiver beams need to be aligned, which incurs high delay overhead since without a priori knowledge of the transmitter/receiver location, the search space spans the entire angular domain. This is further exacerbated under dynamic conditions (e.g., moving vehicles) where the access to the base station (access point) is highly dynamic with intermittent on-off periods, requiring more frequent beam alignment and signal training. To mitigate this issue, we consider an online stochastic optimization formulation where the goal is to maximize the directivity gain (i.e., received energy) of the beam alignment policy within a time period. We exploit the inherent correlation and unimodality properties of the model, and demonstrate that contextual information improves the performance. To this end, we propose an equivalent structured Multi-Armed Bandit model to optimally exploit the exploration-exploitation tradeoff. In contrast to the classical MAB models, the contextual information makes the lower bound on regret (i.e., performance loss compared with an oracle policy) independent of the number of beams. This is a crucial property since the number of all combinations of beam patterns can be large in transceiver antenna arrays, especially in massive MIMO systems. We further provide an asymptotically optimal beam alignment algorithm, and investigate its performance via simulations.
Boundary torsion and convex caps of locally convex surfaces

We prove that the torsion of any closed space curve which bounds a simply connected locally convex surface vanishes at least $4$ times. This answers a question of Rosenberg related to a problem of Yau on characterizing the boundary of positively curved disks in Euclidean space. Furthermore, our result generalizes the $4$ vertex theorem of Sedykh for convex space curves, and thus constitutes a far reaching extension of the classical $4$ vertex theorem. The proof involves studying the arrangement of convex caps in a locally convex surface, and yields a Bose type formula for these objects.
Quantum prisoners’ dilemma under enhanced interrogation

In the quantum version of prisoners’ dilemma, each prisoner is equipped with a single qubit that the interrogator can entangle. We enlarge the available Hilbert space by introducing a third qubit that the interrogator can entangle with the other two. We discuss an enhanced interrogation technique based on tripartite entanglement and analyze Nash equilibria. We show that for tripartite entanglement approaching a W-state, we calculate the Nash equilibria numerically and show that they coincide with the Pareto-optimal choice where both prisoners cooperate. Upon continuous variation between a W-state and a pure bipartite entangled state, the game is shown to have a surprisingly rich structure. The role of bipartite and tripartite entanglement is explored to explain that structure. As an application, we consider an evolutionary game based on our quantum game with a network of agents on a square lattice with periodic boundary conditions and show that the strategy corresponding to Nash equilibrium completely dominates without placing any restrictions on the initial set of strategies.
A computationally efficient approach to modeling contact problems and fracture closure using superposition method

Abstract The shape of fractures in an elastic medium under different stress distributions have been well studied in the literature, however, the fracture closure process during unloading has not been investigated thoroughly. The fracture surface is normally assumed to be perfectly smooth so that only the width and stress intensity at the fracture tip are critical in the analysis. In reality, the creation of a fracture in a rock seldom produces smooth surfaces and the resulting asperities on the fracture surfaces can impact fracture closure. Correctly modeling this fracture closure behavior has numerous applications in structural engineering and earth sciences. In this article, we present an approach to model fracture closure behavior in a 2D and 3D elastic media. The fracture surface displacements under arbitrary normal load are derived using superposition method. The contact stress, deformation, and fracture volume evolution are estimated in a computationally efficient manner for various fracture surface properties. When compared with the traditional integral transform methods used to model fracture closure, the superposition method presented in this study produces comparable results with significant less computation time. In addition, with the aid of parallel computation, large scale fracture closure and contact problems can be successfully simulated using our proposed dynamic fracture closure model (DFCM) with very modest computation times.
A lower bound for higher topological complexity of real projective space

Abstract We obtain an explicit formula for the best lower bound for the higher topological complexity, TC k ( R P n ) , of real projective space implied by mod 2 cohomology.
Integrative Analysis of Patient Health Records and Neuroimages via Memory-Based Graph Convolutional Network

With the arrival of the big data era, more and more data are becoming readily available in various real-world applications and those data are usually highly heterogeneous. Taking computational medicine as an example, we have both Electronic Health Records (EHR) and medical images for each patient. For complicated diseases such as Parkinson's and Alzheimer's, both EHR and neuroimaging information are very important for disease understanding because they contain complementary aspects of the disease. However, EHR and neuroimage are completely different. So far the existing research has been mainly focusing on one of them. In this paper, we proposed a framework, Memory-Based Graph Convolution Network (MemGCN), to perform integrative analysis with such multi-modal data. Specifically, GCN is used to extract useful information from the patients' neuroimages. The information contained in the patient EHRs before the acquisition of each brain image is captured by a memory network because of its sequential nature. The information contained in each brain image is combined with the information read out from the memory network to infer the disease state at the image acquisition timestamp. To further enhance the analytical power of MemGCN, we also designed a multi-hop strategy that allows multiple reading and updating on the memory can be performed at each iteration. We conduct experiments using the patient data from the Parkinson's Progression Markers Initiative (PPMI) with the task of classification of Parkinson's Disease (PD) cases versus controls. We demonstrate that superior classification performance can be achieved with our proposed framework, compared with existing approaches involving a single type of data.
A Spiking Neural Dynamical Drift-Diffusion Model on Collective Decision Making with Self-Organized Criticality

This article proposes a novel collective decision-making scheme to solve the multi-agent drift-diffusion model problem with the help of spiking neural networks. The exponential integrate-and-fire model is used here to capture the individual dynamics of each agent in the system, and we name this new model the Exponential Decision Making (EDM) model. We demonstrate analytically and experimentally that the gating variable for instantaneous activation follows Boltzmann probability distribution, and the collective system reaches meta-stable critical states under the Markov chain premise. With mean field analysis, we derive the global criticality from local dynamics and achieve a power-law distribution. Critical behavior of EDM exhibits the convergent dynamics of Boltzmann distribution, and we conclude that the EDM model inherits the property of self-organized criticality, i.e., the system will eventually evolve toward criticality.