cssi/SciSciGPT-SciSciNet huggingface dataset:
Synthesis and anti-HIV activity of l-β-3′-C-cyano-2′,3′-unsaturated nucleosides and l-3′-C-cyano-3′-deoxyribonucleosides

Abstract An efficient synthetic method was developed for l -β-3′- C -cyano-2′,3′-unsaturated nucleosides and l -3′- C -cyano-3′-deoxyribonucleosides. The key intermediate 11 was obtained from l -xylose, from which a series of pyrimidine and purine nucleosides were prepared in high yield by the coupling of 11 and various silyl-protected bases in the presence of TMSOTf. These nucleosides were eliminated, followed by deprotecting to give l -β-3′- C -cyano-2′,3′-unsaturated nucleosides. When selectively deprotected by hydrazine hydrate in buffered acetic acid–pyridine followed by treatment with potassium carbonate in methanol, l -3′- C -cyano-3′-deoxyribonucleosides were obtained. The synthesized nucleosides were tested for anti-HIV activity.
Middleware Building Blocks for Workflow Systems

This paper describes a building-block approach to the design of scientific workflow systems. We discuss RADICALCybertools as one implementation of building-block concept, showing how they are designed and developed in accordance with this approach. This paper offers three main contributions: (i) showing the relevance of the design principles underlying the building blocks approach to support scientific workflows on high performance computing platforms; (ii) illustrating a set of building blocks that enable multiple points of integration, “unifying” conceptual reasoning across otherwise very different tools and systems; and (iii) case studies discussing how RADICAL-Cybertools are integrated with existing workflow, workload, and general purpose computing systems, and used to develop domain-specific workflow systems.
Hypervalent iodine oxidation of 2-aryl-1,2,3,4-tetrahydro-4-quinolones: An expedient route to naturally occurring 4-alkoxy-2-arylquinolines

Abstract Easily accessible 2-aryl-1,2,3,4-tetrahydro-4-quinolones are readily oxidized to the corresponding 4-alkoxy-2-arylquinolines using a relatively safe hypervalent iodine reagent, [hydroxy (tosyloxy)iodo]benzene (HTIB), in high yields, thus providing a concise route to an important class of naturally occurring alkaloids.
Synthesis of 2‐silaoxane via 1,3‐ photocycloaddition

Irradiation of an aryl group with a silyl tethered alkene yields a tetracyclic 2-silaoxane with high regiose-lectivity. The multicyclic structure has been further modified to give an unstable tricyclic diol. Photocycloaddition between cyclopentene and phenylcyclopropane gave a single major cycloadduct without cyclopropyl ring opening, indicating that the putative radical intermediate involved in cycloaddition apparently has a very short lifetime if it exists at all.
The CuI-catalyzed exo-selective asymmetric multicomponent [C+NC+CC] coupling reaction

Abstract A novel CuI-catalyzed exo-selective asymmetric [C+NC+CC] coupling reaction is reported that provides unprecedented access to a variety of highly functionalized 4,5-trans disubstituted pyrrolidines in a single operation. The reaction complements and extends our AgI-catalyzed endo-selective [C+NC+CC] asymmetric coupling reaction.
Selective Remote Functionalization of Alkyl Side Chains in the Coupling of Fischer Carbene Complexes with Conjugated Enediynes

Abstract The reactions of various enediyne derivatives with Fischer carbene complexes has been examined. In most cases, benzofuran derivatives featuring a functionalized side chain were produced as a result of the coupling reaction. Reactions performed in chlorobenzene produced mostly this class of products. The major product was usually the alkene derivative, although in the presence of chlorine atom sources, chloride derivatives were also observed.
A novel case of cationic rearrangement involving a phenonium ion

Abstract A cationic rearrangement was observed in the intramolecular electrophilic substitution of a trioxygenated benzyl ether. The crystal structure of the product is presented.
Synthesis of the hindered N,N,N′-trisubstituted guanidine moiety of martinelline and martinellic acid

Abstract Hindered guanidines can be prepared by reaction of cyanamides with amines in hexafluoroisopropanol at 90–120°C. This sequence was used for preparing guanidinium acid 21 as a model for martinellic acid.
A remarkable ene-like reaction: Development and synthetic applications

Abstract A catalytic ene-like reaction of aldehydes with those vinyl ethers that display the oxygen functionality at the central carbon of an allylic system, e.g., 2-methoxypropene, is discussed in detail. The reaction is promoted by 0.05 equiv. of the 1:1 complex of Yb(fod)3 and acetic acid, and it is forms the centerpiece of our synthesis of chlorovulone II, mitomycinoids and phyllanthocin.
Addition of Allylindium Reagents to Aldehydes Substituted at Cα or Cβ with Heteroatomic Functional Groups. Analysis of the Modulation in Diastereoselectivity Attainable in Aqueous, Organic, and Mixed Solvent Systems

The stereochemical course of indium-promoted allylations to α- and β-oxy aldehydes has been investigated in solvents ranging from anhydrous THF to pure H2O. The free hydroxyl derivatives react with...
Synthesis of 5-Amino-9-benzyl-6-formyl-4-methoxy-2-pivaloylamino-7,8-dihydropyrimido[4,5-b]azepine. A potentially useful intermediate towards the synthesis of pyrimidoazepine based folic acid derivatives

Synthesis of the title compound is described via an intramolecular 1,3-dipolar cycloaddition reaction between the pyrimidine nitrile oxide 24 and an alkyne dipolarophile tethered to the 6-position of the pyrimidine ring. The resulting isoxazolopyrimidoazepine cycloadduct 25 was treated with molybdenum hexacarbonyl to provide the titled enamino aldehyde 26.
Details associated with the bimolecular 1,4-dipolar cycloaddition reaction of cross-conjugated heteroaromatic betaines

Abstract A series of 3,3-disubstituted bicyclic anhydro-4-hydroxy-2-oxo-1,3-thiazinium hydroxides are easily prepared from the reaction of 3H-thiolactams with 1,3-bielectrophiles. These cross-conjugated heteroaromatic betaines undergo regio- and diastereospecific 1,4-dipolar cycloaddition with electron-rich and electron-deficient π-bonds to produce 1,4-cycloadducts containing a carbonyl sulfide bridge. A representative betaine dipole and a 1,4-cycloadduct were characterized by single crystal X-ray determinations. In certain cases, the initially formed cycloadduct can be induced to lose COS on further heating. The frontier orbital coefficients of the thiazinium betaine were determined by semi-empirical MOPAC calculations with the PM3 Hamiltonian. The HOMO of the 1,4-dipole is dominant for reactions with electron-deficient dipolarophiles such as N-phenylmaleimide, while the LUMO becomes important for cycloaddition to more electron-rich species such as ynamines or vinyl ethers.
An efficient synthesis of γ-amino β-ketoester by cross-claisen condensation with α-amino acid derivatives

Abstract Cross-ester condensation between N -protected amino acid ester and the lithium enolate prepared from alkyl acetate gave the corresponding β-ketoester in high yield without the formation of the tertiary alcohol that is commonly seen as by-product. This interesting reaction is applicable to the amino acid derivatives with suitable N -protecting groups, which can help to stabilize the reaction intermediates.
Is there stereoelectronic control in formation and cleavage of tetrahedral intermediates

Deslongchamps' hypothesis of stereoelectronic control states that preferential cleavage of a tetrahedral intermediate occurs when a leaving group is antiperiplanar to two lone pairs. It is argued that the evidence supporting the hypothesis is suspect. An alternative explanation is that product stabilities bias the results. A more suitable test is hydrolysis of cyclic amidines and related species. Product studies show substantial cleavage of the bond that is antiperiplanar to only one lone pair and syn to the other, especially in five- and seven-membered rings. Even in the most favorable cases, six-membered rings, antiperiplanar lone pairs provide <2 kcal/mol of transition-state stabilization.
In-House Digital Workflow for the Management of Acute Mandible Fractures

Computer-aided design and additive manufacturing are revolutionizing oral and maxillofacial surgery. Current methods use virtual surgical planning sessions and custom plate milling via third-party vendors, which is costly and time-consuming, negating the effectiveness in acute facial trauma. This technical note describes a state-of-the-art in-house expedited digital workflow for computer-aided virtual fracture reduction, 3-dimensional printing, and preoperative reconstruction plate adaptation for the management of an acute mandible fracture. This process uses the computed tomographic scan a patient receives in the emergency department or clinic. The DICOM (Digital Imaging and Communications in Medicine) data are transferred into US Food and Drug Administration–approved software, in which the fracture is segmented and virtually reduced based on condylar position, midline symmetries, and occlusion if present. The reduced mandible is then printed, which serves as a template for preoperative reconstruction plate adaptation. This method facilitates a virtually reduced fractured mandible, 3-dimensionally printed model, and ideally adapted plates ready for sterilization before surgery within 2 hours after DICOM upload.
The direct formation of H2O2 from H2 and O2 over palladium catalysts

Abstract The direct formation of H 2 O 2 from H 2 and O 2 is an attractive alternative to the current technology that involves the hydrogenation of an alkylanthroquinone to the corresponding hydroquinone, followed by the reaction of the hydroquinone with oxygen to yield H 2 O 2 . The direct reaction is generally catalyzed by palladium, although there is evidence that the addition of small amounts of platinum may enhance the yield of peroxide. The palladium may be in a supported form or it may be present as a colloid derived from PdCl 4 2− ions in solution. The reaction takes place in a three-phase system that includes the reagent gases, the palladium catalyst, and a solvent, which is usually water. Other solvents, including methanol, are also effective. The solutions contain an inorganic acid and often halide ions (Cl − or Br − ) to inhibit the decomposition of H 2 O 2 and perhaps the nonselective oxidation of H 2 to H 2 O. At sufficiently high concentrations of an acid, the dissolution of supported palladium occurs. Because of the three-phase system, the rates may be transport-limited. The solubility of H 2 in H 2 O is small; therefore, high reagent pressures are used to enhance formation rates and the ultimate yields of H 2 O 2 . Safety issues that result from having the reagents at high pressures are significant, and to avoid contact of H 2 and O 2 in the gas phase, the introduction of H 2 through a membrane has been demonstrated. A number of fundamental issues remain unresolved including the active state of the palladium and the reaction mechanism, although it has been shown that the oxygen remains in a diatomic form during the production of H 2 O 2 .
Genomic insights into multidrug-resistance, mating and virulence in Candida auris and related emerging species

Candida auris is an emergent multidrug-resistant fungal pathogen causing increasing reports of outbreaks. While distantly related to C. albicans and C. glabrata, C. auris is closely related to rarely observed and often multidrug-resistant species from the C. haemulonii clade. Here, we analyze near complete genome assemblies for the four C. auris clades and three related species, and map intra- and inter-species rearrangements across the seven chromosomes. Using RNA-Seq-guided gene predictions, we find that most mating and meiosis genes are conserved and that clades contain either the MTLa or MTLα mating loci. Comparing the genomes of these emerging species to those of other Candida species identifies genes linked to drug resistance and virulence, including expanded families of transporters and lipases, as well as mutations and copy number variants in ERG11. Gene expression analysis identifies transporters and metabolic regulators specific to C. auris and those conserved with related species which may contribute to differences in drug response in this emerging fungal clade. Candida auris is an emergent fungal pathogen that is resistant to multiple antifungals. Here, Munoz et al. analyse genomic sequences for isolates from each of the four major C. auris clades and for three related species, and identify genetic features associated with virulence, antifungal resistance and mating.
The Legend of Cosmological Homogeneity

For more than a half century cosmologists have been guided by the assumption that matter is distributed homogeneously on sufficiently large scales. On the other hand, observations have consistently yielded evidence for inhomogeneity in the distribution of matter right up to the limits of most surveys. The apparent paradox can be understood in terms of the role that paradigms play in the evolution of science.
Formation of Metal−Anion Arrays within Layered Perovskite Hosts. Preparation of a Series of New Metastable Transition-Metal Oxyhalides, (MCl)LaNb2O7 (M = Cr, Mn, Fe, Co)

A new series of transition-metal oxyhalides (MCl)LaNb2O7 (M = Cr, Mn, Fe, Co) have been prepared by a simple topochemical route. Layered perovskite hosts (ALaNb2O7, A = Li, Na, K or Rb) were reacted with the corresponding anhydrous metal halides under mild reaction conditions (<400 °C). The compounds were examined by X-ray powder diffraction; the series appears to be isostructural with (CuCl)LaNb2O7, and the layer spacings, with the exception of M = Co, follow the trend expected from transition-metal cationic radii. Thermal analysis with differential scanning calorimetry (DSC) shows the materials to be metastable where all four compounds decompose exothermically above 690 °C.
Computational investigation of the suitability of heterocyclic aromatic compounds with two heteroatoms in the 1 and 3 ring positions as dienes for the diels alder reaction

Semiempirical and density functional theory computational studies were carried out with the target determining the reactivity of five membered heterocycles with heteroatoms in the 1 and 3 positions as dienes for Diels-Alder reactions. The relative reactivity was evaluated in their reaction with acetylene, ethylene, and cyclopropene as dienophiles for cycloaddition. Qualitative criteria such as uniformity of heterocycle bond orders, change of bond orders and frontier molecular orbital energies in transformation of reactants into transition state structures were used to determine the relative reactivity in comparison with furan. These results are compared with the computed activation barriers as well as with experimental findings, where available. If cycloaddition is feasible with these heterocycles, a new synthetic transformation of simple organic compounds to valuable prostaglandin derivatives can be accomplished.
The impact of thigh and shank marker quantity on lower extremity kinematics using a constrained model.

Musculoskeletal models are commonly used to quantify joint motions and loads during human motion. Constraining joint kinematics simplifies these models but the implications of the placement and quantity of markers used during data acquisition remains unclear. The purpose of this study was to establish the effects of marker placement and quantity on lower extremity kinematics calculated using a constrained-kinematic model. We hypothesized that a constrained-kinematic model would produce lower-extremity kinematics errors that correlated with the number of tracking markers removed from the thigh and shank. Healthy-young adults (N = 10) walked on a treadmill at slow, moderate, and fast speeds while skin-mounted markers were tracked using motion capture. Lower extremity kinematics were calculated for 256 combinations of leg and shank markers to establish the implications of marker placement and quantity on joint kinematics. Marker combinations that yielded differences greater than 5 degrees were tested with paired t-tests and the relationship between number of markers and kinematic errors were modeled with polynomials to determine goodness of fit (R2). Sagittal joint and hip coronal kinematics errors were smaller than documented errors caused by soft-tissue artifact, which tends to be approximately 5 degrees, when excluding thigh and shank markers. Joint angle and center kinematic errors negatively correlated with the number of markers included in the analyses (R2 > 0.97) and typically showed the greatest error reductions when two markers were included on the thigh or shank segments. Further, we demonstrated that a simplified marker set that included markers on the pelvis, lateral knee condyle, lateral malleolus, and shoes produced kinematics that strongly agreed with the traditional marker set that included 3 tracking markers for each segment. Constrained-kinematic models are resilient to marker placement and quantity, which has implications on study design and post-processing workflows.
An efficacious method for the halogenation of β-dicarbonyl compounds under mildly acidic conditions

Abstract A variety of 1,3-diketones, β-ketoesters and malonates can be chlorinated in high yields using sodium hypochlorite in a 5:2 mixture of acetone/acetic acid at 0 °C for 1 h. Similarly, bromination of these dicarbonyl substrates can be accomplished under the same conditions using sodium hypobromite.
A Facile Synthesis of 3-Substituted-2-aminothiophenes and 1,3-Disubstituted-2-methylthiopyrroles

Electron-rich 3-functionalized-2-aminothiophenes 6 and 1,3-disubstituted-2-methylthiopyrroles 10 were synthesized from substituted allyl benzotriazoles 2 and isothiocyanates 3 via condensation and subsequent heterocyclization.
Stereoselective Synthesis of Both Enantiomers of N-Aryl Indoles with Axially Chiral N−C Bonds¶

N-Aryl indoles with axially chiral N-C bonds were synthesized by stereoselective nucleophilic aromatic substitution reactions of planar chiral tricarbonyl(2,6-disubstituted-1-fluorobenzene)chromium complexes. The stereochemistry of the products is highly dependent on the position of the substituent in the indole. When indoles devoid of a substituent at the 2-position were used, N-aryl indole chromium complexes having anti orientation with respect to the tricarbonylchromium fragment were obtained diastereoselectively. In contrast, 2-substituted indoles gave the N-aryl indoles with syn orientation between the tricarbonylchromium fragment and the benzene ring of the indole. These results demonstrate that we have succeeded in synthesizing both enantiomers of N-aryl indoles utilizing an identical planar chiral arene chromium complex.
Interactive analysis and assessment of single-cell copy-number variations

We present Ginkgo (http://qb.cshl.edu/ginkgo), a user-friendly, open-source web platform for the analysis of single-cell copy-number variations (CNVs). Ginkgo automatically constructs copy-number profiles of cells from mapped reads and constructs phylogenetic trees of related cells. We validated Ginkgo by reproducing the results of five major studies. After comparing three commonly used single-cell amplification techniques, we concluded that degenerate oligonucleotide-primed PCR is the most consistent for CNV analysis.
Top quark physics

A review is presented of the current experimental status of the top quark sector of the Standard Model. The measurements summarized include searches for electroweak single top production, the latest results on the $t\bar t$ production cross-section, and searches for new physics in top quark production and decay. In addition, the recent measurement of the top quark mass to a precision of 0.7% is highlighted.
New preparation of o-aryloxyphenols via cyclohexenone oxides

Abstract Reaction of cyclohexenone oxides with phenols under basic two-phase conditions with sonication followed by oxidation represents a new, efficient two-step synthesis of o -aryloxyphenols.
Synthesis of 4,7-substituted 1,10-phenanthrolines

4-7-Dialkylated-1,10-phenanthrolines 3a-f and 4c-d have been synthesized in high yields from 4,7-dimetlyl-1,10-phenanthroline and 3,4,7,8-tetrametlyl-1,10-phenanthroline, respectively, via lithiation followed by alkylation. These substituted phenanthrolines form complexes with lithium, and salts with proton acids, containing unusual ligand : cation ratios
Synthesis of Phloroglucinol Monoaryl Ethers

A variety of novel functionalized phloroglucinol mono­aryl ethers have been synthesized using a two-step procedure. Target ethers were synthesized by coupling electron-deficient aryl fluorides with 3,5-dimethoxyphenol via nucleophilic aromatic substitution (SNAr) in N-methylpyrrolidone and cesium carbonate. Subsequent boron tribromide-mediated demethylation gave a series of phloroglucinol monoaryl ethers in good overall yields.
Endohedral Silicon Fullerenes SiN (27 ≤ N ≤ 39)

We have performed an unbiased search for the lowest-energy geometric structures of medium-sized silicon clusters SiN (27 ≤ N ≤ 39) using a genetic algorithm and nonorthogonal-tight-binding method, followed by a refining and biased search using basin-hopping method coupled with density-functional theory. We show that the carbon fullerene cages are most likely generic cage motifs (“magic cages”) to form low-lying stuffed-cage silicon clusters (beyond the size N > 27). An empirical rule that provides optimal “stuffing/cage” combinations for constructing low-energy endohedral silicon fullerenes is suggested, with a hope that it can provide guidance to future synthesis of “bucky” silicon.
NaV1-xP2S6 (x = 0.16): A New Compound with Infinite Straight (1/∞)[V0.837P2S6]- Chains that Exfoliate Forming Gels

The new 1D chalcogenophosphate material NaV 0.837(6) P 2 S 6 has been synthesized and its structure determined by X-ray powder diffraction analysis. This compound crystallizes in the monoclinic space group P2 1 /n with a = 6.9677(3) A, b = 5.9059(2) A, c = 21.4537(8) A, and β = 92.962(2)° [Z = 4, V = 881.66(8) A 3 ]. The Rietveld refinement led to R p /R wp = 0.0208/ 0.0271 (for 94 parameters refined). The material is isostructural with 1D-NaCrP 2 S 6 and contains infinite ( 1 /∞)[V 0.837(6) P 2 S 6 ] - chains consisting of randomly occupied edge-sharing [VS 6 ] octahedra defining zigzag ( 1 /∞)[VS 4 ] ribbons that are capped by tetradendate [P 2 S 6 ] ethane-like groups linked to three successive [VS 6 ] polyhedra. Because of the nonstoichiometry of the phase, the charge balance can be written as Na + (V 4+ ) 0.486 (V 3+ ) 0.351 (P 4+ ) 2 (S 2- ) 6 . NaV 0.837(6) P 2 S 6 is soluble in strongly polar organic solvents such as N-methylformamide (NMF). The exfoliation of NaV 0.837(6) P 2 S 6 in NMF leads to gels or to colored colloidal solutions with complex fluid behavior that depends strongly on concentration.
Substituent effects on intramolecular dipolar cycloadditions: The gem-dicarboalkoxy effect

Abstract A gem -dicarboalkoxy effect (rel. rate >20) has been measured and good diastereoselectivity (∼9:1) has been seen for the intramolecular dipolar cycloaddition of 3-substituted 5-hexenyl nitrile oxides.
HiMAP: Robust phylogenomics from highly multiplexed amplicon sequencing.

High-throughput sequencing has fundamentally changed how molecular phylogenetic data sets are assembled, and phylogenomic data sets commonly contain 50- to 100-fold more loci than those generated using traditional Sanger sequencing-based approaches. Here, we demonstrate a new approach for building phylogenomic data sets using single-tube, highly multiplexed amplicon sequencing, which we name HiMAP (highly multiplexed amplicon-based phylogenomics) and present bioinformatic pipelines for locus selection based on genomic and transcriptomic data resources and postsequencing consensus calling and alignment. This method is inexpensive and amenable to sequencing a large number (hundreds) of taxa simultaneously and requires minimal hands-on time at the bench ( 150,000-bp concatenated alignment, ~20% missing character sites across all individuals and amplicons) contained >40,000 phylogenetically informative characters, and although some discordance was observed between analyses, it provided unparalleled resolution of many phylogenetic relationships in this group. Most notably, we found high support for the generic status of Zeugodacus and the sister relationship between Dacus and Zeugodacus. We discuss HiMAP, with regard to its molecular and bioinformatic strengths, and the insight the resulting data set provides into relationships of this diverse insect group.
Age-Optimal Transmission of Rateless Codes in an Erasure Channel

In this paper, we examine a status updating system where updates generated by the source are sent to the monitor through an erasure channel. We assume each update consists of k symbols and the symbol erasure in each time slot follows an independent and identically distributed (i.i.d.) Bernoulli process. We assume rateless coding scheme is adopted at the transmitter and an update can be successfully decoded if k coded symbols are received successfully. We assume perfect feedback available at the source, so that it knows whether a transmitted symbol has been erased instantly. Then, at the beginning of each time slot, the source has the choice to start transmitting a new update, or continue with the transmission of the previous update if it is not delivered yet. We adopt the metric &#x201C;Age of Information&#x201D; (AoI) to measure the freshness of information at the destination, where the AoI is defined as the age of the latest decoded update at the destination. Our objective is to design an optimal online transmission scheme to minimize the time-average AoI. The transmission decision is based on the instantaneous AoI, the age of the update being transmitted, as well as the number of successfully delivered symbols of the update. We formulate the problem as a Markov Decision Process (MDP) and identify the monotonic threshold structure of the optimal policy. Numerical results corroborate the structural properties of the optimal solution.
Transgenerational inheritance of ethanol preference is caused by maternal NPF repression

Rapid or even anticipatory adaptation to environmental conditions can provide a decisive fitness advantage to an organism. The memory of recurring conditions could also benefit future generations; however, neuronally-encoded behavior isn't thought to be inherited across generations. We tested the possibility that environmentally triggered modifications could allow 'memory' of parental experiences to be inherited. In Drosophila melanogaster, exposure to predatory wasps leads to inheritance of a predisposition for ethanol-rich food for five generations. Inhibition of Neuropeptide-F (NPF) activates germline caspases required for transgenerational ethanol preference. Further, inheritance of low NPF expression in specific regions of F1 brains is required for the transmission of this food preference: a maternally derived NPF locus is necessary for this phenomenon, implicating a maternal epigenetic mechanism of NPF-repression. Given the conserved signaling functions of NPF and its mammalian NPY homolog in drug and alcohol disorders, these observations raise the intriguing possibility of NPY-related transgenerational effects in humans.
Designer ideals with high Castelnuovo-Mumford regularity

The purpose of this paper is to give a simple geometric construction of ideals whose Castelnuovo-Mumford regularity is large compared to the generating degree. Moreover, our ideals have the property that the Castelnuovo-Mumford regularity is revealed as late in the resolution as desired.
GenAttack: practical black-box attacks with gradient-free optimization

Deep neural networks are vulnerable to adversarial examples, even in the black-box setting, where the attacker is restricted solely to query access. Existing black-box approaches to generating adversarial examples typically require a significant number of queries, either for training a substitute network or performing gradient estimation. We introduce GenAttack, a gradient-free optimization technique that uses genetic algorithms for synthesizing adversarial examples in the black-box setting. Our experiments on different datasets (MNIST, CIFAR-10, and ImageNet) show that GenAttack can successfully generate visually imperceptible adversarial examples against state-of-the-art image recognition models with orders of magnitude fewer queries than previous approaches. Against MNIST and CIFAR-10 models, GenAttack required roughly 2,126 and 2,568 times fewer queries respectively, than ZOO, the prior state-of-the-art black-box attack. In order to scale up the attack to large-scale high-dimensional ImageNet models, we perform a series of optimizations that further improve the query efficiency of our attack leading to 237 times fewer queries against the Inception-v3 model than ZOO. Furthermore, we show that GenAttack can successfully attack some state-of-the-art ImageNet defenses, including ensemble adversarial training and non-differentiable or randomized input transformations. Our results suggest that evolutionary algorithms open up a promising area of research into effective black-box attacks.
Tiny Codes for Guaranteeable Delay

Future 5G systems will need to support ultra-reliable low-latency communications scenarios. From a latency-reliability viewpoint, it is inefficient to rely on average utility-based system design. Therefore, we introduce the notion of guaranteeable delay which is the average delay plus three standard deviations of the mean. We investigate the trade-off between guaranteeable delay and throughput for the point-to-point wireless erasure links with unreliable and delayed feedback, by bringing together signal flow techniques to the area of coding. We use tiny codes, i.e., sliding window by coding with just 2 packets, and design three variations of selective-repeat ARQ protocols, by building on the baseline scheme, i.e., uncoded ARQ, developed by Ausavapattanakun and Nosratinia: (i) Hybrid ARQ with soft combining at the receiver; (ii) cumulative feedback-based ARQ without rate adaptation; and (iii) coded ARQ with rate adaptation based on the cumulative feedback. Contrasting the performance of these protocols with uncoded ARQ, we demonstrate that the HARQ performs only slightly better, the cumulative feedback-based ARQ does not provide significant throughput while it has a better average delay, and the Coded ARQ can provide gains up to about 40% in terms of throughput. The Coded ARQ also provides delay guarantees, and is robust to various challenges such as imperfect and delayed feedback, burst erasures, and round-trip time fluctuations. This feature may be preferable for meeting the strict end-to-end latency and reliability requirements of the future use cases of ultra-reliable low-latency communications in 5G, such as mission-critical communications and industrial control for critical control messaging.
On the reduction of total‐cost and average‐cost MDPs to discounted MDPs

This article provides conditions under which total-cost and average-cost Markov decision processes (MDPs) can be reduced to discounted ones. Results are given for transient total-cost MDPs with transition rates whose values may be greater than one, as well as for average-cost MDPs with transition probabilities satisfying the condition that there is a state such that the expected time to reach it is uniformly bounded for all initial states and stationary policies. In particular, these reductions imply sufficient conditions for the validity of optimality equations and the existence of stationary optimal policies for MDPs with undiscounted total cost and average-cost criteria. When the state and action sets are finite, these reductions lead to linear programming formulations and complexity estimates for MDPs under the aforementioned criteria.© 2017 Wiley Periodicals, Inc. Naval Research Logistics, 2017
Nonparametric Density Estimation under Adversarial Losses

We study minimax convergence rates of nonparametric density estimation under a large class of loss functions called ``adversarial losses'', which, besides classical L^p losses, includes maximum mean discrepancy (MMD), Wasserstein distance, and total variation distance. These losses are closely related to the losses encoded by discriminator networks in generative adversarial networks (GANs). In a general framework, we study how the choice of loss and the assumed smoothness of the underlying density together determine the minimax rate. We also discuss implications for training GANs based on deep ReLU networks, and more general connections to learning implicit generative models in a minimax statistical sense.
Diversity Gain of One-Shot Communication over Molecular Timing Channels

We study diversity in one-shot communication over molecular timing channels. In the considered channel model the transmitter simultaneously releases a large number of information particles, where the information is encoded in the time of release. The receiver decodes the information based on the random time of arrival of the information particles. We characterize the asymptotic exponential decrease rate of the probability of error as a function of the number of released particles. We denote this quantity as the system diversity gain, as it depends both on the number of particles transmitted as well as the receiver detection method. Three types of detectors are considered: the maximum-likelihood (ML) detector, a linear detector, and a detector that is based on the first arrival (FA) among all the transmitted particles. We show that for random propagation characterized by right-sided unimodal densities with zero mode, the FA detector is equivalent to the ML detector, and significantly outperforms the linear detector. Moreover, even for densities with positive mode, the diversity gain achieved by the FA detector is very close to that achieved by the ML detector and much higher than the gain achieved by the linear detector.
Influencing Flock Formation in Low-Density Settings

Flocking is a coordinated collective behavior that results from local sensing between individual agents that have a tendency to orient towards each other. Flocking is common among animal groups and might also be useful in robotic swarms. In the interest of learning how to control flocking behavior, recent work in the multiagent systems literature has explored the use of influencing agents for guiding flocking agents to face a target direction. The existing work in this domain has focused on simulation settings of small areas with toroidal shapes. In such settings, agent density is high, so interactions are common, and flock formation occurs easily. In our work, we study new environments with lower agent density, wherein interactions are more rare. We study the efficacy of placement strategies and influencing agent behaviors drawn from the literature, and find that the behaviors that have been shown to work well in high-density conditions tend to be much less effective in lower density environments. The source of this ineffectiveness is that the influencing agents explored in prior work tended to face directions optimized for maximal influence, but which actually separate the influencing agents from the flock. We find that in low-density conditions maintaining a connection to the flock is more important than rushing to orient towards the desired direction. We use these insights to propose new influencing agent behaviors, which we dub "follow-then-influence"; agents act like normal members of the flock to achieve positions that allow for control and then exert their influence. This strategy overcomes the difficulties posed by low density environments.
First-order interference of nonclassical light emitted spontaneously at different times

Summary form only given. It is now well known that signal or idler beams of spontaneous parametric down-conversion (SPDC) emitted from two spatially separated domains exhibit first-order interference when certain conditions are satisfied. In this letter, we report an experimental observation of a novel type of quantum interference, in which the sources of SPDC are separated not in space but in time.
Aggregate-Max Nearest Neighbor Searching in the Plane

We study the aggregate nearest neighbor searching for the Max operator in the plane. For a set P of n points and a query set Q of m points, the query asks for a point of P whose maximum distance to the points in Q is minimized. We present data structures for answering such queries for both L1 and L2 distance measures. Previously, only heuristic and approximation algorithms were given for both versions. For the L1 version, we build a data structure of O(n) size in O(nlogn) time, such that each query can be answered in O(m + logn) time. For the L2 version, we build a data structure of O(nloglogn) size in O(nlogn) time, such that each query can be answered in O(m p nlog O(1) n) time, and alternatively, we build a data structure in O(n 2+ ) time and space for any > 0, such that each query can be answered in O(mlogn) time.
Signal Reconstruction from Interferometric Measurements under Sensing Constraints

Abstract We develop a framework in which the problem of signal reconstruction from interferometric measurements amounts to one of basis analysis, with measurements that are linear in the basis coefficients. We leverage a generalized interferometry approach to enable the reconstruction of signals represented in different bases of arbitrary domains. Our framework is unifying in that it applies whether the sought-after information concerns the input signal or a sample object, as well as in settings where we have no control over the relative delays of the two paths of the interferometer. While the linear transformation underlying the measurement system has only a limited number of degrees of freedom set by the constrained sensing structure, we show that compressive signal recovery is achievable without introducing any additional randomization to the measurement setup. We establish performance guarantees under constrained sensing by proving that the transformation satisfies sufficient conditions for successful reconstruction. Also, we propose two control policies to guide the collection of informative measurements given prior knowledge about the constrained sensing structure. By minimizing the mutual coherence of the sampled measurements, the controlled approach is shown to yield further gains in sample size complexity.
Impartial achievement and avoidance games for generating finite groups

We study two impartial games introduced by Anderson and Harary and further developed by Barnes. Both games are played by two players who alternately select previously unselected elements of a finite group. The first player who builds a generating set from the jointly selected elements wins the first game. The first player who cannot select an element without building a generating set loses the second game. After the development of some general results, we determine the nim-numbers of these games for abelian and dihedral groups. We also present some conjectures based on computer calculations. Our main computational and theoretical tool is the structure diagram of a game, which is a type of identification digraph of the game digraph that is compatible with the nim-numbers of the positions. Structure diagrams also provide simple yet intuitive visualizations of these games that capture the complexity of the positions.
Markov processes conditioned on their location at large exponential times

Suppose that (Xt ) t ≥0 is a one-dimensional Brownian motion with negative drift -μ. It is possible to make sense of conditioning this process to be in the state 0 at an independent exponential random time and if we kill the conditioned process at the exponential time the resulting process is Markov. If we let the rate parameter of the random time go to 0, then the limit of the killed Markov process evolves like X conditioned to hit 0, after which time it behaves as X killed at the last time X visits 0. Equivalently, the limit process has the dynamics of the killed "bang-bang" Brownian motion that evolves like Brownian motion with positive drift +μ when it is negative, like Brownian motion with negative drift -μ when it is positive, and is killed according to the local time spent at 0. An extension of this result holds in great generality for a Borel right process conditioned to be in some state a at an exponential random time, at which time it is killed. Our proofs involve understanding the Campbell measures associated with local times, the use of excursion theory, and the development of a suitable analogue of the "bang-bang" construction for a general Markov process. As examples, we consider the special case when the transient Borel right process is a one-dimensional diffusion. Characterizing the limiting conditioned and killed process via its infinitesimal generator leads to an investigation of the h-transforms of transient one-dimensional diffusion processes that goes beyond what is known and is of independent interest.
Privacy-Guaranteed Two-Agent Interactions Using Information-Theoretic Mechanisms

This paper introduces a multi-round interaction problem with privacy constraints between two agents that observe correlated data. The data are assumed to have both public and private features, and the goal of the interaction is to share the public data subject to utility constraints (bounds on the distortion of public feature) while ensuring bounds on the information leakage of the private data at the other agent. The agents alternately share data with one another for a total of $K$ rounds such that each agent initiates sharing over $K/2$ rounds. The interactions are modeled as a collection of $K$ random mechanisms (mappings), one for each round. The goal is to jointly design the $K$ private mechanisms to determine the set of all achievable distortion-leakage pairs at each agent. Arguing that a mutual information-based leakage metric can be appropriate for streaming data settings, this paper: 1) determines the set of all achievable distortion-leakage tuples; 2) shows that the $K$ mechanisms allow for precisely composing the total privacy budget over $K$ rounds without loss; and 3) develops conditions under which interaction reduces the net leakage at both agents and illustrates it for a specific class of sources. The paper then focuses on log-loss distortion to better understand the effect on leakage of using a commonly used utility metric in learning theory. The resulting interaction problem leads to a non-convex sum-leakage-distortion optimization problem that can be viewed as an interactive version of the information bottleneck problem. A new merge-and-search algorithm that extends the classical agglomerative information bottleneck algorithm to the interactive setting is introduced to determine a provable locally optimal solution. Finally, the benefit of interaction under log-loss is illustrated for specific source classes, and the optimality of one-shot is proved for Gaussian sources under both mean-square and log-loss distortions constraints.
Frame Scalings: A Condition Number Approach

Abstract Scaling frame vectors is a simple and noninvasive way to construct tight frames. However, not all frames can be modified to tight frames in this fashion, so in this case we explore the problem of finding the best conditioned frame by scaling, which is crucial for applications like signal processing. We conclude that this problem is equivalent to solving a convex optimization problem involving the operator norm, which is unconventional since this problem was only studied in the perspective of Frobenius norm before. We also further study the Frobenius norm case in relation to the condition number of the frame operator, and the convexity of optimal scalings.
The entropic barrier: a simple and optimal universal self-concordant barrier

We prove that the Fenchel dual of the log-Laplace transform of the uniform measure on a convex body in R is a (1 + o(1))n-self-concordant barrier, improving a seminal result of Nesterov and Nemirovski. This gives the first explicit construction of a universal barrier for convex bodies with optimal self-concordance parameter. The proof is based on basic geometry of log-concave distributions, and elementary duality in exponential families. The result also gives a new perspective on the minimax regret for the linear bandit problem. c © 2015 S. Bubeck & R. Eldan.
The Riemann hypothesis over finite fields: from Weil to the present day

The statement of the Riemann hypothesis makes sense for all global fields, not just the rational numbers. For function fields, it has a natural restatement in terms of the associated curve. Weil’s work on the Riemann hypothesis for curves over finite fields led him to state his famous “Weil conjectures”, which drove much of the progress in algebraic and arithmetic geometry in the following decades. In this article, I describe Weil’s work and some of the ensuing progress. It is my contribution to the book “The legacy of Bernhard Riemann after one hundred and fifty years”, edited by S.T. Yau et al.
Geometry and Physics of Null Infinity

In asymptotically Minkowski space-times, one finds a surprisingly rich interplay between geometry and physics in both the classical and quantum regimes. On the mathematical side it involves null geometry, infinite dimensional groups, symplectic geometry on the space of gravitational connections and geometric quantization via Kahler structures. On the physical side, null infinity provides a natural home to study gravitational radiation and its structure leads to several interesting effects such as an infinite dimensional enlargement of the Poincare group, geometrical expressions of energy and momentum carried by gravitational waves, emergence of non-trivial ‘vacuum configurations’ and an unforeseen interplay between infrared properties of the quantum gravitational field and the enlargement of the asymptotic symmetry group. The goal of this article is to present a succinct summary of this subtle and beautiful interplay.
Random Access Channel Coding in the Finite Blocklength Regime

Consider a random access communication scenario over a channel whose operation is defined for any number of possible transmitters. Inspired by the model recently introduced for the Multiple Access Channel (MAC) with a fixed, known number of transmitters by Polyanskiy, we assume that the channel is invariant to permutations on its inputs, and that all active transmitters employ identical encoders. Unlike Polyanskiy, we consider a scenario in which neither the transmitters nor the receiver know which or how many transmitters are active. We refer to this agnostic communication setup as the Random Access Channel, or RAC. Limited feedback is used to ensure that the collection of active transmitters remains fixed during each epoch. The decoder is tasked with determining from the channel output the number of active transmitters (k) and their messages but not which transmitter sent which message. The central result of this work demonstrates the achievability on a RAC of performance that is first-order optimal for the MAC in operation during each coding epoch. While prior multiple access schemes for a fixed number of transmitters require 2k – 1 simultaneous threshold rules, the proposed scheme uses a single threshold rule and achieves the same dispersion.
Cryogenic System for the Cryomodule Test Stand at Fermilab

This paper describes the cryogenic system for the Cryomodule Test Stand (CMTS) at the new Cryomodule Test Facility (CMTF) located at Fermilab. CMTS is designed for production testing of the 1.3 GHz and 3.9GHz cryomodules to be used in the Linac Coherent Light Source II (LCLSII), which is an upgrade to an existing accelerator at Stanford Linear Accelerator Laboratory (SLAC). This paper will focus on the cryogenic system that extends from the helium refrigeration plant to the CMTS cave. Topics covered will include component design, installation and commissioning progress, and operational plans. The paper will conclude with a description of the heat load measurement plan.