cssi/SciSciGPT-SciSciNet huggingface dataset:
A comparison of phenylboronic acid and phenyltrimethyltin in the palladium‐catalyzed arylation of 1,5‐dialkylimidazoles

A comparison of phenyltrimethyltin vs. phenylboronic acid in the palladium-catalyzed arylation of brominated 5-methyl-1(phenylmethyl)imidazoles is described.
Enantioselective syntheses of tremulenediol A and tremulenolide A

A concise entry to the skeleton of the tremulane sesquiterpenes is described that culminated in the first enantioselective syntheses of tremulenediol A and tremulenolide A. The approach features a series of efficient transition metal-catalyzed reactions commencing with an enantioselective rhodium(II)-catalyzed intramolecular cyclopropanation followed by a regioselective allylic alkylation and a diastereoselective rhodium(I)-catalyzed [5+2] cycloaddition.
Concatenated Catalytic Asymmetric Allene Diboration/Allylation/Functionalization

Palladium-catalyzed enantioselective diboration of prochiral allenes generates a reactive chiral allylboron intermediate which is a versatile reagent for the allylation of carbonyls. Experiments that improve the enantioselectivity of this process, examine the substrate scope, and are directed toward functionalization of the allylation intermediate are described.
Asymmetric Synthesis of α-Aminophosphonate Esters by the Addition of Dialkyl Phosphites to tert-Butanesulfinyl Imines

The KHMDS-mediated addition of dialkyl phosphites to N - tert -butanesulfinyl aldimines and ketimines proceeds in uniformly high yields and diastereoselectivities and thereby enables the rapid and general asymmetric synthesis of α-aminophosphonate esters.
OnACID: Online Analysis of Calcium Imaging Data in Real Time

Optical imaging methods using calcium indicators are critical for monitoring the activity of large neuronal populations in vivo. Imaging experiments typically generate a large amount of data that needs to be processed to extract the activity of the imaged neuronal sources. While deriving such processing algorithms is an active area of research, most existing methods require the processing of large amounts of data at a time, rendering them vulnerable to the volume of the recorded data, and preventing real-time experimental interrogation. Here we introduce OnACID, an Online framework for the Analysis of streaming Calcium Imaging Data, including i) motion artifact correction, ii) neuronal source extraction, and iii) activity denoising and deconvolution. Our approach combines and extends previous work on online dictionary learning and calcium imaging data analysis, to deliver an automated pipeline that can discover and track the activity of hundreds of cells in real time, thereby enabling new types of closed-loop experiments. We apply our algorithm on two large scale experimental datasets, benchmark its performance on manually annotated data, and show that it outperforms a popular offline approach.
Optimal Battery Control Under Cycle Aging Mechanisms in Pay for Performance Settings

We study the optimal control of battery energy storage under a general “pay-for-performance” setup such as providing frequency regulation and renewable integration. In these settings, batteries need to carefully balance the tradeoff between following the instruction signals and their degradation costs in real-time. Existing battery control strategies either do not consider the uncertainty of future signals, or cannot accurately account for battery cycle aging mechanism during operation. In this paper, we take a different approach to the optimal battery control problem. Instead of attacking the complexity of a battery degradation function or the lack of future information one at a time, we address these two challenges together in a joint fashion. In particular, we present an electrochemically accurate and trackable battery degradation model called the rainflow cycle-based model. We prove that the degradation cost is convex. Then, we propose an online control policy with a simple threshold structure and show that it achieves near-optimal performance with respect to an offline controller that has complete future information. We explicitly characterize the optimality gap and show that it is independent to the duration of operation. Simulation results with both synthetic and real regulation traces are conducted to illustrate the theoretical results.
SYNTHESIS OF 19-FLUORORETINAL AND 20-FLUORORETINAL

We have investigated methods to monofluorinate the methyl positions 19 and 20 in retinal, and we describe a general, mild strategy that proceeds in high yields and is compatible with current carbon-13 labeling strategies. The new sequence consists of the conversion of N-methoxy-N-methylamides via the α-chloromethyl ketone to the corresponding γ-hydroxy nitrile, which can subsequently be fluorinated by (diethylamido)sulfur trifluoride (DAST).
One ‐ pot synthesis of novel sulfur and selenium heterocycles by directed ortho‐lithiation

A procedure for the synthesis of benzo[e][1,3]thiazine-2,4-diones from benzamides by directed lithiation and sequential treatment with sulfur and phosgene is reported. Use of thiophosgene afforded 2-thioxo-2,3-dihydro-benzo[e][1,3] thiazin-4-ones. Application of this methodology to benzenesulfonamides afforded the previously unknown 1,1-dioxo-1,2-dihydro-1,4-dithia-2-aza-naphthalen-3-one ring system with phosgene and the 1,2-dioxo-2-phenyl-2,3-dihydrobenzo[e][1,4,2]dithiazine-3-one ring system with thiophosgene. Use of selenium in place of sulfur afforded the novel analogous selenium heterocycles, however in the case of benzamides the use of selenium and phosgene afforded benzo[d]isoselenazol-3-ones unexpectedly.
Far-Ultraviolet Performance of the Berkeley Spectrograph during the ORFEUS-SPAS II Mission

The Berkeley spectrograph aboard the ORFEUS telescope made its second flight on the 14 day ORFEUS-SPAS II mission of the Space Shuttle Columbia in 1996 November/December. Approximately half of the available observing time was dedicated to the Berkeley spectrograph, which was used by both principal and guest investigators. The spectrograph's full bandpass is 390-1218 A; here we discuss its in-flight performance at far-ultraviolet wavelengths, at which most of the observations were performed. The instrument's effective area peaks at 8.9±0.5 cm2 near 1020 A, and the mean spectral resolution is 95 km s-1 FWHM for point sources. Over most of the spectral range, the typical nighttime background event rate in each spectral resolution element was ~0.003 s-1. Simultaneous background observations of an adjacent blank field were provided through a secondary, off-axis aperture. The Berkeley spectrograph's unique combination of sensitivity and resolution provided valuable observations of approximately 105 distinct astronomical targets, which ranged in distance from the Earth's own Moon to some of the brightest active galactic nuclei.
Rhodium(II) catalyzed cyclopropanation/cycloaddition reactions of the bis(diazo)piperidin-2-one system

Abstract Bis(diazo)piperidin-2-ones that are devoid of a donor substituent in the 4-position undergo a one-pot cyclopropanation/cascade dipole formation/cycloaddition reaction to produce novel azapolycycles.
SYNTHESIS, REACTIONS, AND STRUCTURAL STUDIES OF TWO-CARBON BRIDGED SPIROPENTANES

The syntheses of three 4,5-disubstituted derivatives of tricyclo[4.1.0.01,3]heptane (3) are reported. The relative stereochemistry of the oxygen substituents in these compounds was deduced by 13C N...
1-Amino-3-siloxy-1,3-butadienes: Highly Reactive Dienes for the Diels-Alder Reaction.

1-Amino-3-siloxy-1,3-butadienes represent a novel class of heteroatom-containing dienes with several useful properties. These dienes can be prepared efficiently by deprotonation of readily available vinylogous amides with potassium hexamethylsilazide, followed by silylation of the corresponding potassium enolates. This protocol has been found to be quite general for the preparation of various dienes containing different silyl and amino groups. Amino siloxy dienes readily undergo [4 + 2] cycloadditions with a wide range of electron-deficient dienophiles. The reactions generally occur under very mild conditions to afford the corresponding [4 + 2] adducts in high yields and with complete regioselectivity. High endo selectivity is observed in the case of N-phenylmaleimide and methacrolein. Other cycloadducts are usually obtained as mixtures of endo/exo diastereomers. The cycloadducts are versatile synthetic intermediates. They can be subjected to deprotonation, reduction, and Wittig olefination without any hy...
Can Policy Affect Initiation of Addictive Substance Use? Evidence from Opioid Prescribing

Drug control policy can have unintended consequences by pushing existing users to alternative, possibly more dangerous substances. Policies that target only new users may therefore be especially promising. Using commercial insurance claims data, we provide the first evidence on a set of new policies intended to reduce opioid initiation in the form of limits on initial prescription length. We also provide the first evidence on the impact of must-access prescription drug monitoring programs (MA-PDMPs), laws that do not target new users, on initial opioid use. Although initial limit policies reduce the average length of initial prescriptions, they do so primarily by raising the frequency of short prescriptions, resulting in increases in opioids dispensed to new users. In contrast, we find that MA-PDMPs reduce opioids dispensed to new users, even though they do not explicitly set out to do so. Neither policy significantly affects extreme use such as doctor shopping among new patients, because such behavior is very rare.
Synthesis of a Series of Focally-Substituted Organothiol Dendrons

The synthesis of new organothiol-functionalized dendrons of generation 1−4 is described. Several modifications to the original method for preparation of dendrons are detailed that were found to improve the yield and aid in scale-up. A particularly advantageous method for preparation of an aromatic thiol is reported and is employed in this reaction sequence. Several uses of these dendrons are anticipated and briefly described.
Synthesis of Tetracyclic Flavonoids via Palladium-Catalyzed Intramolecular Oxidative Cyclization

Palladium-catalyzed oxidative cyclization of terminal-olefin-tethered phenols was achieved in good yields (61–90% yields). The reaction was optimized and White catalyst {[1,2-bis-(phenylsulfinyl)ethane]palladium(II)acetate} provided the best yield in the presence of benzoquinone as an oxidant. The reaction tolerated both electron-donating and electron-withdrawing substituents on the substrates, and the structure of the tetracyclic flavonoids was confirmed using single-crystal X-ray analysis. The study represents the first example of successful allylic C–H activation/ C–O bond formation using terminal-olefin-tethered phenols.
Drug concentrations in post-mortem specimens

A meta-analysis of drug concentrations in post-mortem specimens is presented. The analysis involved 50 commonly used drugs and their concentrations in femoral blood, other blood (such as cardiac blood), vitreous humor, muscle, liver, kidney, brain, heart, lung, spleen, and bile. A total of 10 993 analytical results from 5375 post-mortem cases in 388 studies were gathered and the ratios of drug concentrations in tissue material to median femoral blood concentrations were calculated. Analytical results from the laboratory's own database (years 2000-2018) were also included. The results show that the variation of ratios between post-mortem specimens and femoral blood is highly compound dependent. This database can be utilized in interpretation of toxicological results in cases where femoral blood is not available. The specimens with similar concentrations as in femoral blood were vitreous humor, muscle, and other blood, such as cardiac blood, and the highest concentrations were generally measured from liver and bile. For these reasons we suggest the following order for biological specimens to be used for a quantitative toxicological analysis in cases where femoral blood is not available: 1. other blood, 2. muscle, 3. vitreous humor, 4. brain, 5. heart, 6. spleen, 7. kidney, 8. liver, and 9. bile.
Haystack: systematic analysis of the variation of epigenetic states and cell-type specific regulatory elements.

Motivation With the increasing amount of genomic and epigenomic data in the public domain, a pressing challenge is to integrate these data to investigate the role of epigenetic mechanisms in regulating gene expression and maintenance of cell-identity. To this end, we have implemented a computational pipeline to systematically study epigenetic variability and uncover regulatory DNA sequences. Results Haystack is a bioinformatics pipeline to identify hotspots of epigenetic variability across different cell-types, cell-type specific cis-regulatory elements, and associated transcription factors. Haystack is generally applicable to any epigenetic mark and provides an important tool to investigate the mechanisms underlying epigenetic switches during development. This software is accompanied by a set of precomputed tracks, which may be used as a valuable resource for functional annotation of the human genome. Availability and implementation The Haystack pipeline is implemented as an open-source, multiplatform, Python package called haystack_bio freely available at https://github.com/pinellolab/haystack_bio. Contact lpinello@mgh.harvard.edu or gcyuan@jimmy.harvard.edu. Supplementary information Supplementary data are available at Bioinformatics online.
Species-level bacterial community profiling of the healthy sinonasal microbiome using Pacific Biosciences sequencing of full-length 16S rRNA genes

Pan-bacterial 16S rRNA microbiome surveys performed with massively parallel DNA sequencing technologies have transformed community microbiological studies. Current 16S profiling methods, however, fail to provide sufficient taxonomic resolution and accuracy to adequately perform species-level associative studies for specific conditions. This is due to the amplification and sequencing of only short 16S rRNA gene regions, typically providing for only family- or genus-level taxonomy. Moreover, sequencing errors often inflate the number of taxa present. Pacific Biosciences’ (PacBio’s) long-read technology in particular suffers from high error rates per base. Herein, we present a microbiome analysis pipeline that takes advantage of PacBio circular consensus sequencing (CCS) technology to sequence and error correct full-length bacterial 16S rRNA genes, which provides high-fidelity species-level microbiome data. Analysis of a mock community with 20 bacterial species demonstrated 100% specificity and sensitivity with regard to taxonomic classification. Examination of a 250-plus species mock community demonstrated correct species-level classification of > 90% of taxa, and relative abundances were accurately captured. The majority of the remaining taxa were demonstrated to be multiply, incorrectly, or incompletely classified. Using this methodology, we examined the microgeographic variation present among the microbiomes of six sinonasal sites, by both swab and biopsy, from the anterior nasal cavity to the sphenoid sinus from 12 subjects undergoing trans-sphenoidal hypophysectomy. We found greater variation among subjects than among sites within a subject, although significant within-individual differences were also observed. Propiniobacterium acnes (recently renamed Cutibacterium acnes) was the predominant species throughout, but was found at distinct relative abundances by site. Our microbial composition analysis pipeline for single-molecule real-time 16S rRNA gene sequencing (MCSMRT, https://github.com/jpearl01/mcsmrt ) overcomes deficits of standard marker gene-based microbiome analyses by using CCS of entire 16S rRNA genes to provide increased taxonomic and phylogenetic resolution. Extensions of this approach to other marker genes could help refine taxonomic assignments of microbial species and improve reference databases, as well as strengthen the specificity of associations between microbial communities and dysbiotic states.
Chiral tertiary amine N-oxides in asymmetric epoxidation of α,β-unsaturated ketones

Chiral tertiary amine N-oxides have been shown to undergo stereoselective oxygen transfer reaction in the epoxidation of chalcone derivatives with modest to good enantioselectivity.
Biomass pyrolysis kinetics: A comparative critical review with relevant agricultural residue case studies

Biomass pyrolysis is a fundamental thermochemical conversion process that is of both industrial and ecological importance. From designing and operating industrial biomass conversion systems to modeling the spread of wildfires, an understanding of solid state pyrolysis kinetics is imperative. A critical review of kinetic models and mathematical approximations currently employed in solid state thermal analysis is provided. Isoconversional and model-fitting methods for estimating kinetic parameters are comparatively evaluated. The thermal decomposition of biomass proceeds via a very complex set of competitive and concurrent reactions and thus the exact mechanism for biomass pyrolysis remains a mystery. The pernicious persistence of substantial variations in kinetic rate data for solids irrespective of the kinetic model employed has exposed serious divisions within the thermal analysis community and also caused the broader scientific and industrial community to question the relevancy and applicability of all kinetic data obtained from heterogeneous reactions. Many factors can influence the kinetic parameters, including process conditions, heat and mass transfer limitations, physical and chemical heterogeneity of the sample, and systematic errors. An analysis of thermal decomposition data obtained from two agricultural residues, nutshells and sugarcane bagasse, reveals the inherent difficulty and risks involved in modeling heterogeneous reaction systems.
The stereocontrolled synthesis of orthogonally protected (R)-α-methyltryptophan

Abstract An expedient and highly stereocontrolled route to (R)-α-methyltryptophan and its orthogonally protected analogs has been developed via a four-step conversion from L-alanine in good overall yields. The stereochemistry of the products is confirmed by X-ray diffraction analysis, NMR spectroscopy and optical rotations.
Asymmetric total synthesis of (+)-fostriecin.

The title compound, a potent protein phosphatase inhibitor and anticancer agent, was prepared by an efficient, multiconvergent asymmetric synthesis. Key transformations include a ring forming olefin metathesis leading to the α,β-unsaturated lactone and creation of the triene moiety via Suzuki cross-coupling.
Diels-Alder reactions of 5-vinyl-1-acyl-2-aryl-2,3-dihydro-4-pyridones: regio- and stereoselective synthesis of octahydroquinolines.

Readily available 5-vinyldihydropyridones 2 undergo Diels−Alder cyclization with various dienophiles to afford novel octahdroquinolines. The process is highly stereoselective and provides heterocyclic products containing synthetically useful functionality.
Reliability of sequential hypothesis testing can be achieved by an almost-fixed-length test

The maximum type-I and type-II error exponents associated with the newly introduced almost-fixed-length hypothesis testing is characterized. In this class of tests, the decision-maker declares the true hypothesis almost always after collecting a fixed number of samples n; however in very rare cases with exponentially small probability the decision maker is allowed to collect another set of samples (no more than polynomial in n). This class of hypothesis tests are shown to bridge the gap between the classical hypothesis testing with a fixed sample size and the sequential hypothesis testing, and improve the trade-off between type-I and type-II error exponents.
Learning modality-invariant representations for speech and images

In this paper, we explore the unsupervised learning of a semantic embedding space for co-occurring sensory inputs. Specifically, we focus on the task of learning a semantic vector space for both spoken and handwritten digits using the TIDIGITs and MNIST datasets. Current techniques encode image and audio/textual inputs directly to semantic embeddings. In contrast, our technique maps an input to the mean and log variance vectors of a diagonal Gaussian from which sample semantic embeddings are drawn. In addition to encouraging semantic similarity between co-occurring inputs, our loss function includes a regularization term borrowed from variational autoencoders (VAEs) which drives the posterior distributions over embeddings to be unit Gaussian. We can use this regularization term to filter out modality information while preserving semantic information. We speculate this technique may be more broadly applicable to other areas of cross-modality/domain information retrieval and transfer learning.
On a nonlocal extension of differentiation

Abstract We study an integral equation that extends the problem of anti-differentiation. We formulate this equation by replacing the classical derivative with a known nonlocal operator similar to those applied in fracture mechanics and nonlocal diffusion. We show that this operator converges weakly to the classical derivative as a nonlocality parameter vanishes. Using Fourier transforms, we find the general solution to the integral equation. We show that the nonlocal antiderivative involves an infinite dimensional set of functions in addition to an arbitrary constant. However, these functions converge weakly to zero as the nonlocality parameter vanishes. For special types of integral kernels, we show that the nonlocal antiderivative weakly converges to its classical counterpart as the nonlocality parameter vanishes.
Modeling of Lead Halide Perovskites for Photovoltaic Applications

We report first-principles calculations, using the full potential linear augmented plane wave method, on six lead halide semiconductors, namely, CH3NH3PbI3, CH3NH3PbBr3, CsPbX3 (X = Cl, Br, I), and RbPbI3. Exchange is modeled using the modified Becke–Johnson potential. With an appropriate choice of the parameter that defines this potential, an excellent agreement is obtained between calculated and experimental band gaps of the six compounds.
Minimum ranks of sign patterns via sign vectors and duality

A sign pattern matrix is a matrix whose entries are from the set {+,â,0}. The minimum rank of a sign pattern matrix A is the minimum of the ranks of the real matrices whose entries have signs equal to the corresponding entries of A. It is shown in this paper that for any mAn sign pattern A with minimum rank n â 2, rational realization of the minimum rank is possible. This is done using a new approach involving sign vectors and duality. It is shown that for each integer n â¥ 9, there exists a nonnegative integer m such that there exists an m A n sign pattern matrix with minimum rank n â 3 for which rational realization is not possible. A characterization of m A n sign patterns A with minimum rank n â 1 is given (which solves an open problem in Brualdi et al. [R. Brualdi, S. Fallat, L. Hogben, B. Shader, and P. van den Driessche. Final report: Workshop on Theory and Applications of Matrices Described by Patterns. Banff International Research Station, Jan. 31 â Feb. 5, 2010.]), along with a more general description of sign patterns with minimum rank r, in terms of sign vectors of certain subspaces. Several related open problems are stated along the way.
A new biophysical metric for interrogating the information content in human genome sequence variation: Proof of concept.

The 21st century emergence of genomic medicine is shifting the paradigm in biomedical science from the population phenotype to the individual genotype. In characterizing the biology of disease and health disparities in population genetics, human populations are often defined by the most common alleles in the group. This definition poses difficulties when categorizing individuals in the population who do not have the most common allele(s). Various epidemiological studies have shown an association between common genomic variation, such as single nucleotide polymorphisms (SNPs), and common diseases. We hypothesize that information encoded in the structure of SNP haploblock variation in the human leukocyte antigen-disease related (HLA-DR) region of the genome illumines molecular pathways and cellular mechanisms involved in the regulation of host adaptation to the environment. In this paper we describe the development and application of the normalized information content (NIC) as a novel metric based on SNP haploblock variation. The NIC facilitates translation of biochemical DNA sequence variation into a biophysical quantity derived from Boltzmann’s canonical ensemble in statistical physics and used widely in information theory. Our normalization of this information metric allows for comparisons of unlike, or even unrelated, regions of the genome. We report here NIC values calculated for HLA-DR SNP haploblocks constructed by Haploview, a product of the International Haplotype Map Project. These haploblocks were scanned for potential regulatory elements using ConSite and miRBase, publicly available bioinformatics tools. We found that all of the haploblocks with statistically low NIC values contained putative transcription factor binding sites and microRNA motifs, suggesting correlation with genomic regulation. Thus, we were able to relate a mathematical measure of information content in HLA-DR SNP haploblocks to biologically relevant functional knowledge embedded in the structure of DNA sequence variation. We submit that NIC may be useful in analyzing the regulation of molecular pathways involved in host adaptation to environmental pathogens and in decoding the functional significance of common variation in the human genome. Key words: Information theory, entropy, genomic variation, biological information.
Multi-sensor slope change detection

We develop a mixture procedure for multi-sensor systems to monitor data streams for a change-point that causes a gradual degradation to a subset of the streams. Observations are assumed to be initially normal random variables with known constant means and variances. After the change-point, observations in the subset will have increasing or decreasing means. The subset and the rate-of-changes are unknown. Our procedure uses a mixture statistics, which assumes that each sensor is affected by the change-point with probability $$p_0$$ . Analytic expressions are obtained for the average run length and the expected detection delay of the mixture procedure, which are demonstrated to be quite accurate numerically. We establish the asymptotic optimality of the mixture procedure. Numerical examples demonstrate the good performance of the proposed procedure. We also discuss an adaptive mixture procedure using empirical Bayes. This paper extends our earlier work on detecting an abrupt change-point that causes a mean-shift, by tackling the challenges posed by the non-stationarity of the slope-change problem.
Deflecting Adversarial Attacks with Pixel Deflection

CNNs are poised to become integral parts of many critical systems. Despite their robustness to natural variations, image pixel values can be manipulated, via small, carefully crafted, imperceptible perturbations, to cause a model to misclassify images. We present an algorithm to process an image so that classification accuracy is significantly preserved in the presence of such adversarial manipulations. Image classifiers tend to be robust to natural noise, and adversarial attacks tend to be agnostic to object location. These observations motivate our strategy, which leverages model robustness to defend against adversarial perturbations by forcing the image to match natural image statistics. Our algorithm locally corrupts the image by redistributing pixel values via a process we term pixel deflection. A subsequent wavelet-based denoising operation softens this corruption, as well as some of the adversarial changes. We demonstrate experimentally that the combination of these techniques enables the effective recovery of the true class, against a variety of robust attacks. Our results compare favorably with current state-of-the-art defenses, without requiring retraining or modifying the CNN.
Large-Scale Replication Projects in Contemporary Psychological Research

Replication is complicated in psychological research because studies of a given psychological phenomenon can never be direct or exact replications of one another, and thus effect sizes vary from on...
Faster and Sample Near-Optimal Algorithms for Proper Learning Mixtures of Gaussians

We provide an algorithm for properly learning mixtures of two single-dimensional Gaussians without any separability assumptions. Given ~ O(1=" 2 ) samples from an unknown mixture, our algorithm
Equivariant unirationality of del Pezzo surfaces of degree 3 and 4

A variety X with an action of a finite group G is said to be G-unirational if there is a G-equivariant dominant rational map $$V \dasharrow X$$ where V is a faithful linear representation of G. This generalizes the usual notion of unirationality. We determine when X is G-unirational for any complex del Pezzo surface X of degree at least 3.
A purely combinatorial approach to simultaneous polynomial recurrence modulo 1

Using purely combinatorial means we obtain results on simultaneous Diophantine approximation modulo 1 for systems of polynomials with real coefficients and no constant term.
Centralized Multi-Node Repair Regenerating Codes

In a distributed storage system, recovering from multiple failures is a critical and frequent task that is crucial for maintaining the system’s reliability and fault-tolerance. In this paper, we focus on the problem of repairing multiple failures in a centralized way, which can be desirable in many data storage configurations; furthermore, we show that a significant repair traffic reduction is possible. First, the fundamental trade-off between the repair bandwidth and the storage size for functional repair is established. Using a graph-theoretic formulation, the optimal tradeoff is identified as the solution to an integer optimization problem, for which a closed-form expression is derived. Expressions of the extreme points, namely the minimum storage multi-node repair (MSMR) and minimum bandwidth multi-node repair (MBMR) points, are obtained. Second, we describe a general framework for converting single erasure minimum storage regenerating codes to MSMR codes. The repair strategy for $e$ failures is similar to that for a single failure; however, certain extra requirements need to be satisfied by the repairing functions for a single failure. For illustration, the framework is applied to product-matrix codes and interference alignment codes. Furthermore, we prove that the functional MBMR point is not achievable for linear exact-repair codes. We also show that the exact-repair minimum bandwidth cooperative repair codes achieve an interior point, that lies near the MBMR point, when $k \equiv 1 \mod e$ , $k$ being the minimum number of nodes needed to reconstruct the entire data. Finally, for $k> 2e, e\mid k$ , and $e \mid d$ , where $d$ is the number of helper nodes during repair, we show that the functional repair trade-off is not achievable under exact repair, except for maybe a small portion near the MSMR point, which parallels the results for single-erasure repair by Shah et al.
The Cayley-Dickson Construction in ACL2.

The Cayley-Dickson Construction is a generalization of the familiar construction of the complex numbers from pairs of real numbers. The complex numbers can be viewed as two-dimensional vectors equipped with a multiplication. The construction can be used to construct, not only the two-dimensional Complex Numbers, but also the four-dimensional Quaternions and the eight-dimensional Octonions. Each of these vector spaces has a vector multiplication, v_1*v_2, that satisfies: 1. Each nonzero vector has a multiplicative inverse. 2. For the Euclidean length of a vector |v|, |v_1 * v_2| = |v_1| |v2|. Real numbers can also be viewed as (one-dimensional) vectors with the above two properties. ACL2(r) is used to explore this question: Given a vector space, equipped with a multiplication, satisfying the Euclidean length condition 2, given above. Make pairs of vectors into "new" vectors with a multiplication. When do the newly constructed vectors also satisfy condition 2?
Objective Prism Emission-Line Searches for Active Galactic Nuclei

Objective-prism surveys for UV-excess and emission-line objects, especially the First and Second Byurakan Surveys, have been central to the study of active galactic nuclei (AGNs). We review previous line-selected surveys for AGNs and discuss their contribution to our understanding of the AGN phenomena. In addition, we present results from the KPNO International Spectroscopic Survey, a modern digital objective-prism survey for emission line objects. This survey is discovering substantial numbers of new AGNs, in particular low-luminosity AGNs and LINERs.
Analytification is the limit of all tropicalizations

We introduce extended tropicalizations for closed subvarieties of toric varieties and show that the analytification of a quasprojective variety over a nonarchimedean field is naturally homeomorphic to the inverse limit of the tropicalizations of its quasiprojective embeddings.
Models and Algorithms for Graph Watermarking

We introduce models and algorithmic foundations for graph watermarking. Our approach is based on characterizing the feasibility of graph watermarking in terms of keygen, marking, and identification functions defined over graph families with known distributions. We demonstrate the strength of this approach with exemplary watermarking schemes for two random graph models, the classic Erdős-Renyi model and a random power-law graph model, both of which are used to model real-world networks.
Uniform bounds for the Iitaka fibration

We give effective bounds for the uniformity of the Iitaka fibration. These bounds follow from an effective theorem on the birationality of some adjoint linear series. In particular we derive an effective version of the main theorem in [19].
The Effect of Data Swapping on Analyses of American Community Survey Data

edit implemented by the U.S. Census Bureau. This paper attempts to study the eect that the Census Bureau’s data swapping algorithm has on the joint distribution of a pair of categorical variables. More specically, data swapping is simulated hundreds of times per swap rate for a range of swap rates, and the Cram er’s V statistic is calculated for each table generated from the swapped data. These tables are created from Census Bureau data at a particular geography, e.g. the table of race by marital status for a certain block in Pittsburgh, Pennsylvania. There are also two kinds of data swapping performed in this analysis: non-targeted and targeted swapping, with targeted swapping being a more complex procedure than non-targeted swapping.
DOOB-MARTIN COMPACTIFICATION OF A MARKOV CHAIN FOR GROWING RANDOM WORDS SEQUENTIALLY.

We consider a Markov chain that iteratively generates a sequence of random finite words in such a way that the nth word is uniformly distributed over the set of words of length 2n in which n letters are a and n letters are b: at each step an a and a b are shuffled in uniformly at random among the letters of the current word. We obtain a concrete characterization of the Doob-Martin boundary of this Markov chain and thereby delineate all the ways in which the Markov chain can be conditioned to behave at large times. Writing N(u) for the number of letters a (equivalently, b) in the finite word u, we show that a sequence (un ) n∈ℕ of finite words converges to a point in the boundary if, for an arbitrary word ν, there is convergence as n tends to infinity of the probability that the selection of N(ν) letters a and N(ν) letters b uniformly at random from un and maintaining their relative order results in ν. We exhibit a bijective correspondence between the points in the boundary and ergodic random total orders on the set {a1, b1, a2, b2, …} that have distributions which are separately invariant under finite permutations of the indices of the a's and those of the b's. We establish a further bijective correspondence between the set of such random total orders and the set of pairs (μ, ν) of diffuse probability measures on [0,1] such that ½(μ + ν) is Lebesgue measure: the restriction of the random total order to {a1, b1,…, an, bn } is obtained by taking X1,…, Xn (resp. Y1,… ,Yn ) i.i.d. with common distribution μ (resp. ν), letting (Z1,…, Z2n) be {X1, Y1,…, Xn , Yn } in increasing order, and declaring that the kth smallest element in the restricted total order is ai (resp. bj ) if Zk = Xi (resp. Zk = Yj ).
Cycle bases of reduced powers of graphs

We define what appears to be a new construction. Given a graph G and a positive integer k , the reduced k th power of G , denoted G ( k ) , is the configuration space in which k indistinguishable tokens are placed on the vertices of G , so that any vertex can hold up to k tokens. Two configurations are adjacent if one can be transformed to the other by moving a single token along an edge to an adjacent vertex. We present propositions related to the structural properties of reduced graph powers and, most significantly, provide a construction of minimum cycle bases of G ( k ) . The minimum cycle basis construction is an interesting combinatorial problem that is also useful in applications involving configuration spaces. For example, if G is the state-transition graph of a Markov chain model of a stochastic automaton, the reduced power G ( k ) is the state-transition graph for k identical (but not necessarily independent) automata. We show how the minimum cycle basis construction of G ( k ) may be used to confirm that state-dependent coupling of automata does not violate the principle of microscopic reversibility, as required in physical and chemical applications.
Synchronization of Coupled Oscillators: The Taylor Expansion of the Inverse Kuramoto Map

Synchronization in the networks of coupled oscillators is a widely studied topic in different areas. It is well-known that synchronization occurs if the connectivity of the network dominates heterogeneity of the oscillators. Despite extensive study on this topic, the quest for sharp closed-form synchronization tests is still in vain. In this paper, we present an algorithm for finding the Taylor expansion of the inverse Kuramoto map. We show that this Taylor series can be used to obtain a hierarchy of increasingly accurate approximate tests with low computational complexity. These approximate tests are then used to estimate the threshold of synchronization as well as the position of the synchronization manifold of the network.
Periodontal health and the lifecourse approach in bioarchaeology

Healthy periodontal tissues are essential to maintaining attachment, stability, and retention of teeth. The concept of ‘health’ is problematic however and includes both physical and psycho-social characteristics. The challenge for bioarchaeologists is defining what physical expression begins to affect an individual’s well-being. Here we apply a lifecourse approach to the measurement of periodontal tissue depth (CEJ-AC) at M1 in a prehistoric sample (N = 162) from the American Southwest to test the hypothesis that age and sex differences bear the greatest impact on the expression of periodontitis. CEJ-AC at M1 increased significantly (p<.001) across age stages from 1.5 ±0.5mm (15-20yo) to 4.25 ±0.25mm in the old age group (40-50yo). Occlusal surface wear and alveolar crest (AC) resorption were considerably variable (non-significant) between sexes; however, tooth loss at M1 is more than double among females compared to males in the final decades 40-50yo and 50-60yo. Results support the hypothesis that periodontal tissue loss differentially affects females across the lifecourse. Bacterial infection, chronic gingivitis, and bony resorption cause the physical symptoms of periodontal disease but may not be accompanied by pain or altered functionality. The outcome of the disease process is tooth loss, which can affect functionality and quality of life. Periodontal ‘health’ is therefore best interpreted in bioarchaeological samples around the point that alveolar recession results in tooth loss and altered functionality.
Inertial effects on the stress generation of active fluids

Suspensions of self-propelled bodies generate a unique mechanical stress owing to their motility that impacts their large-scale collective behavior. For microswimmers suspended in a fluid with negligible particle inertia, we have shown that the virial swim stress is a useful quantity to understand the rheology and nonequilibrium behaviors of active soft matter systems. For larger self-propelled organisms such as fish, it is unclear how particle inertia impacts their stress generation and collective movement. Here we analyze the effects of finite particle inertia on the mechanical pressure (or stress) generated by a suspension of self-propelled bodies. We find that swimmers of all scales generate a unique swim stress and Reynolds stress that impact their collective motion. We discover that particle inertia plays a similar role as confinement in overdamped active Brownian systems, where the reduced run length of the swimmers decreases the swim stress and affects the phase behavior. Although the swim and Reynolds stresses vary individually with the magnitude of particle inertia, the sum of the two contributions is independent of particle inertia. This points to an important concept when computing stresses in computer simulations of nonequilibrium systems: The Reynolds and the virial stresses must both be calculated to obtain the overall stress generated by a system.
ON THE ORBIT DECOMPOSITION OF FINITE QUANDLES

We study the structure of finite quandles in terms of subquandles. Every finite quandle Q decomposes in a natural way as a union of disjoint Q-complemented subquandles; this decomposition coincides with the usual orbit decomposition of Q. Conversely, the structure of a finite quandle with a given orbit decomposition is determined by its structure maps. We describe an algorithm for finding quandle structures on a disjoint union of quandles.
Massively multilingual adversarial speech recognition

We report on adaptation of multilingual end-to-end speech recognition models trained on as many as 100 languages. Our findings shed light on the relative importance of similarity between the target and pretraining languages along the dimensions of phonetics, phonology, language family, geographical location, and orthography. In this context, experiments demonstrate the effectiveness of two additional pretraining objectives in encouraging language-independent encoder representations: a context-independent phoneme objective paired with a language-adversarial classification objective.
Stable pairs and the HOMFLY polynomial

Given a planar curve singularity, we prove a conjecture of Oblomkov–Shende, relating the geometry of its Hilbert scheme of points to the HOMFLY polynomial of the associated algebraic link. More generally, we prove an extension of this conjecture, due to Diaconescu–Hua–Soibelman, relating stable pair invariants on the conifold to the colored HOMFLY polynomial of the algebraic link. Our proof uses wall-crossing techniques to prove a blowup identity on the algebro-geometric side. We prove a matching identity for the colored HOMFLY polynomials of a link using skein-theoretic techniques.
Code Diversity in Multiple Antenna Wireless Communication

The standard approach to the design of individual space-time codes is based on optimizing diversity and coding gains. This geometric approach leads to remarkable examples, such as perfect space-time block codes (?Perfect space-time block codes.? F. Oggier et al., Trans. Inf. Theory, vol. 52, no. 9, pp. 3885-3902, Sep. 2006), for which the complexity of maximum-likelihood (ML) decoding is considerable. Code diversity is an alternative and complementary approach where a small number of feedback bits are used to select from a family of space-time codes. Different codes lead to different induced channels at the receiver, where channel state information (CSI) is used to instruct the transmitter how to choose the code. This method of feedback provides gains associated with beamforming while minimizing the number of feedback bits. Thus, code diversity can be viewed as the integration of space-time coding with a fixed set of beams. It complements the standard approach to code design by taking advantage of different (possibly equivalent) realizations of a particular code design. Feedback can be combined with suboptimal low-complexity decoding of the component codes to match ML decoding performance of any individual code in the family. It can also be combined with ML decoding of the component codes to improve performance beyond ML decoding performance of any individual code. One method of implementing code diversity is the use of feedback to adapt the phase of a transmitted signal. The values of code diversity is verified in the simulations on 4 ? 4 quasi-orthogonal space-time block code (QOSTBC), multi-user detection of Alamouti signaling and the Golden code. It shows that our code diversity scheme is more robust in the case of erroneous feedback compared with other low-rate feedback schemes such as transmit antenna selection and its variations. This paper introduces a family of full rate circulant codes which can be linearly decoded by Fourier decomposition of circulant matrices within the code diversity framework.
Search-based motion planning for quadrotors using linear quadratic minimum time control

In this work, we propose a search-based planning method to compute dynamically feasible trajectories for a quadrotor flying in an obstacle-cluttered environment. Our approach searches for smooth, minimum-time trajectories by exploring the map using a set of short-duration motion primitives. The primitives are generated by solving an optimal control problem and induce a finite lattice discretization on the state space which can be explored using a graph-search algorithm. The proposed approach is able to generate resolution-complete (i.e., optimal in the discretized space), safe, dynamically feasibility trajectories efficiently by exploiting the explicit solution of a Linear Quadratic Minimum Time problem. It does not assume a hovering initial condition and, hence, is suitable for fast online re-planning while the robot is moving. Quadrotor navigation with online re-planning is demonstrated using the proposed approach in simulation and physical experiments and comparisons with trajectory generation based on state-of-art quadratic programming are presented.
An improved model of color confinement

We consider the free energy $W[J] = W_k(H)$ of QCD coupled to an external source $J_\mu^b(x) = H_\mu^b \cos(k \cdot x)$, where $H_\mu^b$ is, by analogy with spin models, an external "magnetic" field with a color index that is modulated by a plane wave. We report an optimal bound on $W_k(H)$ and an exact asymptotic expression for $W_k(H)$ at large $H$. They imply confinement of color in the sense that the free energy per unit volume $W_k(H)/V$ and the average magnetization $m(k, H) ={1 \over V} {\p W_k(H) \over \p H}$ vanish in the limit of constant external field $k \to 0$. Recent lattice data indicate a gluon propagator $D(k)$ which is non-zero, $D(0) \neq 0$, at $k = 0$. This would imply a non-analyticity in $W_k(H)$ at $k = 0$. We present a model that is consistent with the new results and exhibits (non)-analytic behavior. Direct numerical tests of the bounds are proposed.