cssi/SciSciGPT-SciSciNet huggingface dataset:
Trans-splicing of the C. elegans let-7 primary transcript developmentally regulates let-7 microRNA biogenesis and let-7 family microRNA activity

ABSTRACT The sequence and roles in developmental progression of the microRNA let-7 are conserved. In general, transcription of the let-7 primary transcript ( pri-let- 7) occurs early in development, whereas processing of the mature let-7 microRNA arises during cellular differentiation. In Caenorhabditis elegans and other animals, the RNA-binding protein LIN-28 post-transcriptionally inhibits let-7 biogenesis at early developmental stages, but the mechanisms by which LIN-28 does this are not fully understood. Nor is it understood how the developmental regulation of let-7 might influence the expression or activities of other microRNAs of the same seed family. Here, we show that pri-let-7 is trans-spliced to the SL1 splice leader downstream of the let-7 precursor stem-loop, which produces a short polyadenylated downstream mRNA, and that this trans-splicing event negatively impacts the biogenesis of mature let-7 microRNA in cis . Moreover, this trans-spliced mRNA contains sequences that are complementary to multiple members of the let-7 seed family ( let-7fam ) and negatively regulates let-7fam function in trans . Thus, this study provides evidence for a mechanism by which splicing of a microRNA primary transcript can negatively regulate said microRNA in cis as well as other microRNAs in trans .
Facile preparation of protected benzylic and heteroarylmethyl amines via room temperature Curtius rearrangement

Abstract A step-wise, room temperature procedure for acyl azide formation and the subsequent Curtius rearrangement of phenyl and heteroaryl acetic acids is described. We have developed a protocol for room temperature Curtius rearrangement in MeOH or CHCl 3 that provides an improvement over standard conditions, avoiding the use of additives or heat. This room temperature optimization of the Curtius rearrangement prevents the formation of side products often observed with benzylic acids, allowing access to a variety of benzylic and heteroarylmethyl amines.
PERFLUOROALKYL HYPOBROMITES : SYNTHESIS AND REACTIVITY WITH SOME FLUOROALKENES

Abstract The first perfluoroalkyl hypobromites have been prepared by the reaction of bromine(I) fluorosulfate with perfluorinated tertiary alkoxides of general formula RfC (CF3)2ONa where RfCF3 or CF3CF2. These hypobromites are of lower thermal stability but they behave similarly to analogous hypochlorites and decompose rapidly above −20 °C to give CF3C(O)CF3 and either CF3Br or CF3CF2Br. New polyfluoroethers generated from the reaction of perfluoroalkyl hypobromites with fluoroalkenes have been characterized by 19F and IH NMR spectroscopy, IR spectroscopy and MS.
Catalysis by very small Au clusters

Abstract We review recent theoretical and experimental work on the catalytic properties of Au clusters that contain a few atoms and are supported on an oxide surface. The clusters are mass-selected and landed slowly on the oxide surface in ultra-high vacuum. STM measurements show that the clusters do not fragment and do not damage the surface when they are deposited nor do they coarsen after deposition. Their catalytic activity changes non-monotonically with the number of atoms and is sensitive to the nature of the support and to additives (hydroxyls, water, Na, Cl) present on the surface. Binary clusters (e.g. AunSr) can be more active than unary ones. Very recent work has managed to study catalysis by such clusters under realistic pressure conditions; their performance is very different from (and sometimes better than) that of large clusters.
Synthesis of 2-thio- and 2-oxoimidazoles via cascade addition-cycloisomerization reactions of propargylcyanamides.

A methodology to generate 2-thio- and 2-oxoimidazoles through an addition−cyclization−isomerization reaction of propargylcyanamides with thiol and alcohol nucleophiles is described. In general, the reaction sequence allows for the rapid formation of highly substituted 2-thio- and 2-oxoimidazoles in good to excellent yields.
Selective Nucleophilic Attack of Trisulfides. An ab Initio Study

The nucleophilic substitution reactions of three trisulfides by thiolate were evaluated at MP2(full)/6-31+G* and MP4SDTQ(fc)/6-311+G**//MP2(full)/6-31+G*. The results show that the gas-phase mechanism at MP2/6-31+G* is addition−elimination. Kinetically, there is a 2−5 kcal mol-1 preference for attack at a terminal sulfur over a central sulfur in the same trisulfide. This preference for the terminal sulfur is due to more steric hindrance encountered when the nucleophile attacks the central sulfur versus attacking a terminal sulfur. Hydrogen bonding between the nucleophile and the trisulfide also assists in directing attack to the terminal position. Attack at the terminal sulfur is also thermodynamically favored, a result of the thiosulfenate being a better leaving group than the thiolate. These results provide theoretical support to the findings of Myers et al. that the trigger mechanism for activation of calichaemicin and related enediyne antitumor agents occurs by a multistep process, with a displacement...
A fast and accurate method for detection of IBD shared haplotypes in genome-wide SNP data

Identical by descent (IBD) segments are used to understand a number of fundamental issues in genetics. IBD segments are typically detected using long stretches of identical alleles between haplotypes in phased, whole-genome SNP data. Phase or SNP call errors in genomic data can degrade accuracy of IBD detection and lead to false-positive/negative calls and to under/overextension of true IBD segments. Furthermore, the number of comparisons increases quadratically with sample size, requiring high computational efficiency. We developed a new IBD segment detection program, FISHR (Find IBD Shared Haplotypes Rapidly), in an attempt to accurately detect IBD segments and to better estimate their endpoints using an algorithm that is fast enough to be deployed on very large whole-genome SNP data sets. We compared the performance of FISHR to three leading IBD segment detection programs: GERMLINE, refined IBD, and HaploScore. Using simulated and real genomic sequence data, we show that FISHR is slightly more accurate than all programs at detecting long (>3 cm) IBD segments but slightly less accurate than refined IBD at detecting short (~1 cm) IBD segments. More centrally, FISHR outperforms all programs in determining the true endpoints of IBD segments, which is crucial for several applications of IBD information. FISHR takes two to three times longer than GERMLINE to run, whereas both GERMLINE and FISHR were orders of magnitude faster than refined IBD and HaploScore. Overall, FISHR provides accurate IBD detection in unrelated individuals and is computationally efficient enough to be utilized on large SNP data sets >60 000 individuals.
RAPID BERGMAN CYCLIZATION OF 1,2-DIETHYNYLHETEROARENES

The synthesis and cyclization of acyclic quinoxaline, pyridine, and pyrimidine enediynes (1−3) are described. These compounds were prepared using palladium(0) coupling of trimethylsilyl acetylene t...
Crystal structure of a new lead zinc acetate alkoxide, Pb2Zn2(C2H3O2)4(C3H7O2)4

In this report, the preparation and crystal structure of a heterometallic acetate alkoxide, Pb[sub 2]Zn[sub 2](C[sub 2]H[sub 3]O[sub 2])[sub 4](C[sub 3]H[sub 7]O[sub 2])[sub 4] are described. Single crystals were isolated from a lead zinc acetate based precursor solution used for the sol-gel processing of lead zinc niobate.
Regio and stereoselective conversion of Δ4-uronic acids to l-Ido- and d-glucopyranosiduronic acids

Abstract Synthesis of l -ido- and d -glucopyranosiduronic acids was performed starting from protected Δ 4 -uronic acids 3a-f . Bromination of the C-4,5 double bond provided the trans-diaxial bromohydrin derivatives 6a-d , which were converted to the corresponding epoxides 7a-d in high yields. Direct reduction of these epoxides using borane-tetrahydrofuran complex afforded the d -glucopyranosiduronic acids 9b-d , while Lewis acid rearrangment through the C-4 keto intermediate 10b-d afforded the l -idopyranosiduronic acids 11b-d .
Effect of the amine group on relative bond strengths in cubane and azacubanes

We have carried out an ab initio self-consistent-field molecular orbital study of the structures and relative bond strengths of some monoamine derivatives of cubane, azacubane, and 1,3-diazacubane. Our focus has been on the effect of the NH2 group on the strengths of the endocyclic strained bonds in these molecules, and, in particular, on the conformation dependence of this effect. Our results show a consistent bond-weakening observed in one [and only one] C-C or C-N bond adjacent to the site of NH2 substitution. We find that the particular bond that is weakened is in all cases essentially coplanar with the C-NH2 bond and the position of the most negative electrostatic potential of the amine nitrogen. This direction-specific bond-weakening is viewed as an example of the anomeric effect.
Multiple infection of cells changes the dynamics of basic viral evolutionary processes

The infection of cells by multiple copies of a given virus can impact viral evolution in a variety of ways, yet some of the most basic evolutionary dynamics remain underexplored. Using computational models, we investigate how infection multiplicity affects the fixation probability of mutants, the rate of mutant generation, and the timing of mutant invasion. An important insight from these models is that for neutral and disadvantageous phenotypes, rare mutants initially enjoy a fitness advantage in the presence of multiple infection of cells. This arises because multiple infection allows the rare mutant to enter more target cells and to spread faster, while it does not accelerate the spread of the resident wild-type virus. The rare mutant population can increase by entry into both uninfected and wild-type-infected cells, while the established wild-type population can initially only grow through entry into uninfected cells. Following this initial advantageous phase, the dynamics are governed by drift or negative selection, respectively, and a higher multiplicity reduces the chances that mutants fix in the population. Hence, while increased infection multiplicity promotes the presence of neutral and disadvantageous mutants in the short-term, it makes it less likely in the longer term. We show how these theoretical insights can be useful for the interpretation of experimental data on virus evolution at low and high multiplicities. The dynamics explored here provide a basis for the investigation of more complex viral evolutionary processes, including recombination, reassortment, as well as complementary/inhibitory interactions.
Intermolecular and intramolecular reactions of resolved 2-alkoxytetrahydrofuran-3-yl and 2-alkoxytetrahydropyran-3-yl radicals

Abstract Diastereomeric trans -2-alkoxy-3-phenylselenenyltetrahydrofuranyl acetals and trans -2-alkoxy-3-phenyl-selenenyltetrahydropyranyl acetals were prepared from dihydrofuran, dihydropyran, phenylselenenyl bromide, and the alcohols ( S )-methyl lactate, ( S )-methyl hexahydromandelate, and ( R )-pantolactone. The diastereomers were chromatographically separated and were subjected to intermolecular alkylation via generation and trapping of free radicals. Observed diastereoselectivity was higher for 2-alkoxytetrahydrofuran-3-yl radicals than for 2-alkoxytetrahydropyran-3-yl radicals, and highest for acetals involving ( R )-pantolactone. Alcohol exchanges at the anomeric carbon were highly stereocontrolled, and permitted introduction of alkenes for intramolecular trapping of free radical intermediates.
Impacts of Bisphenol A and Ethinyl Estradiol on Male and Female CD-1 Mouse Spleen

The endocrine disruptor bisphenol A (BPA) and the pharmaceutical 17α-ethinyl estradiol (EE) are synthetic chemicals with estrogen-like activities. Despite ubiquitous human exposure to BPA, and the wide-spread clinical use of EE as oral contraceptive adjuvant, the impact of these estrogenic endocrine disrupting chemicals (EDCs) on the immune system is unclear. Here we report results of in vivo dose response studies that analyzed the histology and microstructural changes in the spleen of adult male and female CD-1 mice exposed to 4 to 40,000 μg/kg/day BPA or 0.02 to 2 μg/kg/day EE from conception until 12–14 weeks of age. Results of that analysis indicate that both BPA and EE have dose- and sex-specific impacts on the cellular and microanatomical structures of the spleens that reveal minor alterations in immunomodulatory and hematopoietic functions. These findings support previous studies demonstrating the murine immune system as a sensitive target for estrogens, and that oral exposures to BPA and EE can have estrogen-like immunomodulatory affects in both sexes.
Phosphido Pincer Complexes of Palladium as New Efficient Catalysts for Allylation of Aldehydes

Palladium complexes supported by tridentate phosphido diphosphine ligands (P(o-C6H4PR2)2: 1, R = iPr; 2, R = Ph) have been synthesized, characterized, and tested as catalysts for the electrophilic allylation of aldehydes. The palladium complex 2 resulted in an interesting catalyst for electrophilic allylation in the presence of allyltributyltin, giving good yields under very mild reaction conditions and even in the absence of the solvent.
Regiospecific synthesis of 6‐alkyltropan‐2‐ones

A new synthetic approach for the regiospecific alkylation of the 6-position of the tropane ring system has been developed. Alkylation, desulfonylation and deprotection of tropanes 5 and 12 furnished a series of 6-endo-alkyltropan-2-one derivatives 8a-e, 15a-e and 16a-e (R = Me, Et, n-Pr, n-Bu, Bn) stereoselectively in good yields. The 6-endo isomers 15a-e and 6-exo isomers 16a-e were easily obtained as pure diastereoisomers.
Total Synthesis of (±)-Merrilactone A

The total synthesis of racemic merrilactone A (a neurotrophic agent) is described, featuring simultaneous and stereospecific creation of the C4 and C5 stereocenters via a notable silyloxyfuran Nazarov cyclization. Full details of the successful synthetic strategy are given, as well as several examples of the interesting reactivity of intermediates that were prepared and studied during the execution of the total synthesis. A detailed investigation of the Lewis acid-catalyzed Nazarov cyclization of silyloxyfurans was conducted, including a systematic study of substrate scope and limitations. In addition, experiments were conducted that suggest the participation of Lewis acidic silicon species in the Nazarov cyclization.
The C. elegans heterochronic gene lin-28 coordinates the timing of hypodermal and somatic gonadal programs for hermaphrodite reproductive system morphogenesis

C. elegans heterochronic genes determine the timing of expression of specific cell fates in particular stages of developing larvae. However, their broader roles in coordinating developmental events across diverse tissues have been less well investigated. Here, we show that loss of lin-28, a central heterochronic regulator of hypodermal development, causes reduced fertility associated with abnormal somatic gonadal morphology. In particular, the abnormal spermatheca-uterine valve morphology of lin-28(lf) hermaphrodites traps embryos in the spermatheca, which disrupts ovulation and causes embryonic lethality. The same genes that act downstream of lin-28 in the regulation of hypodermal developmental timing also act downstream of lin-28 in somatic gonadal morphogenesis and fertility. Importantly, we find that hypodermal expression, but not somatic gonadal expression, of lin-28 is sufficient for restoring normal somatic gonadal morphology in lin-28(lf) mutants. We propose that the abnormal somatic gonadal morphogenesis of lin-28(lf) hermaphrodites results from temporal discoordination between the accelerated hypodermal development and normally timed somatic gonadal development. Thus, our findings exemplify how a cell-intrinsic developmental timing program can also control proper development of other interacting tissues, presumably by cell non-autonomous signal(s). This article has an associated 'The people behind the papers' interview.
Regio‐ and stereochemistry of the photo‐ring contraction of 4‐pyrones

Irradiation of 2-ethyl-3-methyl-4-pyrone 3 in aqueous solution led to the formation of trans-4-ethyl-5-methyl-4,4-dihydroxycyclopent-2-enone 4 and trans-2-methyl-3-ethyl-4,5-dihydroxycyclopent-2-enone 5. In the latter case 1 H nmr analysis confirmed the trans-configuration at C 4 and C 5 . These results are consistent with trapping of a photochemically generated oxabicyclohexenyl zwitterion by nucleophilic attack of both sides ot the oxyally system along a path anti to the epoxide ring
Different Products from the Chemical and Electrochemical Reduction of “HgSe2”: [K(2.2.2-cryptand)]2[HgSe2] and [PPh4]2[Hg(Se4)2]·en

[PPh4]2[Hg(Se4)2]·en has been prepared from the electrochemical reduction of “HgSe2”, an intimate mixture of HgSe and Se. [K(2.2.2-cryptand)]2[HgSe2] has been isolated from the reduction of HgSe2 by K in NH3(l) in the presence of 2.2.2-cryptand. 77Se NMR experiments indicate that the difference in product formation is the result of the different reduction methods used.
The preparation of perfluoroaryl substituted isoxazoles via nucleophilic aromatic substitution with lithioalkylisoxazoles

The lithioalkylisoxazoles obtained from C-5 lateral metalation of alkylisoxazoles, 1, add to hexafluorobenzene. When the C-4 substituent was an electron withdrawing tertiary amide moiety, the yields were highest for mono-perfluoroarylation to give 5-pentafluorophenylmethylisoxazoles, 2.
A two-step, single pot procedure for the synthesis of substituted dihydropyrazolo-pyrimidines

In this study, we report a two-step, one pot tandem microwave-assisted reaction of 3-formylchromones with aminopyrazoles followed by a tin-free radical addition. A library of alkyl substituted dihydropyrazolopyrimidines was prepared using this new process.
Atom Economical, One-Pot, Three-Reaction Cascade to Novel Tricyclic 2,4-Dihydro-1H-benzo[f]isochromenes

Reaction of 6-methyl-1-phenylhept-3-yne-2,6-diol with various aldehydes under Lewis acid conditions provides an atom economical, two-component cascade reaction sequence to novel 2,4-dihydro-1H-benzo[f]isochromene compounds. Aliphatic aldehydes as well as electron-deficient and -rich aromatic aldehydes can be used.
Allenes and transition metals: a diverging approach to heterocycles.

An alkynyl allene has been converted to heterocycles possessing an α-alkylidene cyclopentenone, a 4-alkylidene cyclopentenone, or a cross-conjugated triene. Thus, a common intermediate has been converted to three structurally unique compounds by changing only the reaction conditions and, therefore, controlling various reaction pathways.
Local time variation of water ice clouds on Mars as observed by THEMIS

The move of the Odyssey spacecraft during Mars Years 31 and 32 to an orbit with local time near 7:00 AM and PM has enabled the systematic retrieval of water ice cloud optical depth using THEMIS thermal infrared images at a time of day not accessible from Mars Global Surveyor, Mars Reconnaissance Orbiter, or previous Odyssey observations. Because water ice clouds form by condensation, relatively small changes in atmospheric temperature can cause clouds to form or sublimate quickly, and there can be large changes in water ice cloud optical depth over the course of a day. Retrievals of water ice cloud optical depth using THEMIS observations show significant differences in cloud locations and optical depth as a function of local time and season. Cloud optical depth generally increases from the earliest (14:30) to latest (19:30) observations. During the aphelion season the increase from afternoon to evening is primarily associated with the thickening of existing clouds, while during the equinoctial and perihelion seasons there is a proportionally greater increase associated with the formation of clouds in the evening at locations where clouds were not present during the afternoon.
Efficient Syntheses of Secondary and Tertiary 2-Aryl- and 2-Heteroaryl-allyl Alcohols

Reactions of α-aryl-, α-heteroaryl-, and α-heteroatom-substituted masked alkenyllithiums with aldehydes and ketones provide a general method for the synthesis of allylic alcohols substituted with an aryl or heteroaryl in the β position and aryl, heteroaryl or alkyl substituents in the α position via a [1,4]-C→O silicon rearrangement. In the case of reactions with enolizable aldehydes and ketones, anhydrous CeCl3 was used as an additive. High diastereoselectivities are observed for allyl alcohols produced from α-substituted aldehydes.
The Secret Lives of Names?: Name Embeddings from Social Media

Your name tells a lot about you: your gender, ethnicity and so on. It has been shown that name embeddings are more effective in representing names than traditional substring features. However, our previous name embedding model is trained on private email data and are not publicly accessible. In this paper, we explore learning name embeddings from public Twitter data. We argue that Twitter embeddings have two key advantages: (i) they can and will be publicly released to support research community. (ii) even with a smaller training corpus, Twitter embeddings achieve similar performances on multiple tasks comparing to email embeddings. As a test case to show the power of name embeddings, we investigate the modeling of lifespans. We find it interesting that adding name embeddings can further improve the performances of models using demographic features, which are traditionally used for lifespan modeling. Through residual analysis, we observe that fine-grained groups (potentially reflecting socioeconomic status) are the latent contributing factors encoded in name embeddings. These were previously hidden to demographic models, and may help to enhance the predictive power of a wide class of research studies.
Mammalian SWI/SNF collaborates with a polycomb-associated protein to regulate male germline transcription in the mouse.

A deficiency in BRG1, the catalytic subunit of the SWI/SNF chromatin remodeling complex, results in a meiotic arrest during spermatogenesis. Here, we explore the causative mechanisms. BRG1 is preferentially enriched at active promoters of genes essential for spermatogonial pluripotency and meiosis. In contrast, BRG1 is also associated with the repression of somatic genes. Chromatin accessibility at these target promoters is dependent upon BRG1. These results favor a model in which BRG1 coordinates spermatogenic transcription to ensure meiotic progression. In spermatocytes, BRG1 interacts with SCML2, a testis-specific PRC1 factor that is associated with the repression of somatic genes. We present evidence to suggest that BRG1 and SCML2 concordantly regulate genes during meiosis. Furthermore, BRG1 is required for the proper localization of SCML2 and its associated deubiquitylase, USP7, to the sex chromosomes during pachynema. SCML2-associated mono-ubiquitylation of histone H2A lysine 119 (H2AK119ub1) and acetylation of histone lysine 27 (H3K27ac) are elevated in Brg1cKO testes. Coincidentally, the PRC1 ubiquitin ligase RNF2 is activated while a histone H2A/H2B deubiquitylase USP3 is repressed. Thus, BRG1 impacts the male epigenome by influencing the localization and expression of epigenetic modifiers. This mechanism highlights a novel paradigm of cooperativity between SWI/SNF and PRC1.
Intramolecular Cyclization of Tethered Phenyl Ketones. Complementary Stereochemical Results Arising from the Indium-Promoted Ring Closure of Allyl Bromides and the Fluoride Ion-Induced Desilylation of Allylsilanes

The intramolecular indium-promoted cyclization of 4‘-substituted (Z)- and (E)-7-bromo-5-heptenophenones has been examined in aqueous tetrahydrofuran. In every instance, ring closure occurred to deliver the syn-2-vinylcyclopentanol exclusively. The corresponding allylsilanes have been prepared as well, and the course of their fluoride ion-induced cyclization was also studied. In these systems, a kinetic bias for formation of the anti-2-vinylcyclopentanol is observed, although not with the same exclusivity. Accordingly, complementarity in product diastereoselectivity can be realized in purposeful fashion. The data acquired in this investigation suggest that the indium-catalyzed reactions involve intramolecularly coordinated transition states where development of a cis 5/6-bicyclic framework is most energetically feasible. In contrast, the silanes appear to utilize open-chain antiperiplanar transition states. While the latter are not particularly sensitive to double-bond geometry, they are responsive to ster...
Element Abundances: A New Diagnostic for the Solar Wind

We examine the different element abundances exhibited by the closed loop solar corona and the slow speed solar wind. Both are subject to the first ionization potential (FIP) effect, the enhancement in coronal abundance of elements with FIP below 10 eV (e.g., Mg, Si, Fe) with respect to high-FIP elements (e.g., O, Ne, Ar), but with subtle differences. Intermediate elements, S, P, and C, with FIP just above 10 eV, behave as high-FIP elements in closed loops, but are fractionated more like low-FIP elements in the solar wind. On the basis of FIP fractionation by the ponderomotive force in the chromosphere, we discuss fractionation scenarios where this difference might originate. Fractionation low in the chromosphere where hydrogen is neutral enhances the S, P, and C abundances. This arises with nonresonant waves, which are ubiquitous in open field regions, and is also stronger with torsional Alfven waves, as opposed to shear (i.e., planar) waves. We discuss the bearing these findings have on models of interchange reconnection as the source of the slow speed solar wind. The outflowing solar wind must ultimately be a mixture of the plasma in the originally open and closed fields, and the proportions and degree of mixing should depend on details of the reconnection process. We also describe novel diagnostics in ultraviolet and extreme ultraviolet spectroscopy now available with these new insights, with the prospect of investigating slow speed solar wind origins and the contribution of interchange reconnection by remote sensing.
The prejudice first model and foreign policy values: racial and religious bias among conservatives and liberals:

Scholars who study public opinion and American foreign policy have accepted what Rathbun et al. (2016) call the “Vertical Hierarchy Model,” which says that policy attitudes are determined by more a...
Cluster-Wise Cooperative Eco-Approach and Departure Application for Connected and Automated Vehicles Along Signalized Arterials

In recent years, various versions of the eco-approach and departure (EAD) application have been developed and evaluated. This application utilizes signal phase and timing information to allow connected and automated vehicles (CAVs) to approach and depart from a signalized intersection in an energy-efficient manner. To date, most existing works have studied the EAD application from an ego-vehicle perspective (Ego-EAD) using vehicle-to-infrastructure communication, while relatively limited research takes into account cooperation among vehicles at intersections via vehicle-to-vehicle communication. In this paper, we developed a cluster-wise cooperative EAD (Coop-EAD) application for CAVs to further reduce energy consumption compared to existing Ego-EAD applications. Instead of considering CAVs traveling through signalized intersections one at a time, our approach strategically coordinates CAVs’ maneuvers to form clusters using various operating modes: initial vehicle clustering, intracluster sequence optimization, and cluster formation control. The novel Coop-EAD algorithm is applied to the cluster leader, and CAVs in the cluster follow the cluster leader to conduct EAD maneuvers. A preliminary simulation study with a given scenario shows that, compared to an Ego-EAD application, the proposed Coop-EAD application achieves 11% reduction on energy consumption, up to 18% reduction on pollutant emissions, and 50% increase on traffic throughput, respectively.
Kullback-Leibler principal component for tensors is not NP-hard

We study the problem of nonnegative rank-one approximation of a nonnegative tensor, and show that the globally optimal solution that minimizes the generalized Kullback-Leibler divergence can be efficiently obtained, i.e., it is not NP-hard. This result works for arbitrary nonnegative tensors with an arbitrary number of modes (including two, i.e., matrices). We derive a closed-form expression for the KL principal component, which is easy to compute and has an intuitive probabilistic interpretation. For generalized KL approximation with higher ranks, the problem is for the first time shown to be equivalent to multinomial latent variable modeling, and an iterative algorithm is derived that resembles the expectation-maximization algorithm. On the Iris dataset, we showcase how the derived results help us learn the model in an unsupervised manner, and obtain strikingly close performance to that from supervised methods.
How Powerful are Graph Neural Networks

Graph Neural Networks (GNNs) are an effective framework for representation learning of graphs. GNNs follow a neighborhood aggregation scheme, where the representation vector of a node is computed by recursively aggregating and transforming representation vectors of its neighboring nodes. Many GNN variants have been proposed and have achieved state-of-the-art results on both node and graph classification tasks. However, despite GNNs revolutionizing graph representation learning, there is limited understanding of their representational properties and limitations. Here, we present a theoretical framework for analyzing the expressive power of GNNs to capture different graph structures. Our results characterize the discriminative power of popular GNN variants, such as Graph Convolutional Networks and GraphSAGE, and show that they cannot learn to distinguish certain simple graph structures. We then develop a simple architecture that is provably the most expressive among the class of GNNs and is as powerful as the Weisfeiler-Lehman graph isomorphism test. We empirically validate our theoretical findings on a number of graph classification benchmarks, and demonstrate that our model achieves state-of-the-art performance.
Revisiting RCNN: On Awakening the Classification Power of Faster RCNN

Recent region-based object detectors are usually built with separate classification and localization branches on top of shared feature extraction networks. In this paper, we analyze failure cases of state-of-the-art detectors and observe that most hard false positives result from classification instead of localization. We conjecture that: (1) Shared feature representation is not optimal due to the mismatched goals of feature learning for classification and localization; (2) multi-task learning helps, yet optimization of the multi-task loss may result in sub-optimal for individual tasks; (3) large receptive field for different scales leads to redundant context information for small objects. We demonstrate the potential of detector classification power by a simple, effective, and widely-applicable Decoupled Classification Refinement (DCR) network. DCR samples hard false positives from the base classifier in Faster RCNN and trains a RCNN-styled strong classifier. Experiments show new state-of-the-art results on PASCAL VOC and COCO without any bells and whistles.
Unit Hypercube Visibility Numbers of Trees

A visibility representation of a graph G is an assignment of the vertices of G to geometric objects such that vertices are adjacent if and only if their corresponding objects are “visible” each other, that is, there is an uninterrupted channel, usually axis-aligned, between them. Depending on the objects and definition of visibility used, not all graphs are visibility graphs. In such situations, one may be able to obtain a visibility representation of a graph G by allowing vertices to be assigned to more than one object. The visibility number of a graph G is the minimum t such that G has a representation in which each vertex is assigned to at most t objects. In this paper, we explore visibility numbers of trees when the vertices are assigned to unit hypercubes in $$\mathbb {R}^n$$ . We use two different models of visibility: when lines of sight can be parallel to any standard basis vector of $$\mathbb {R}^n$$ , and when lines of sight are only parallel to the nth standard basis vector in $$\mathbb {R}^n$$ . We establish relationships between these visibility models and their connection to trees with certain cubicity values.
Existence of approximate Hermitian-Einstein structures on semi-stable bundles

The purpose of this paper is to investigate canonical metrics on a semi-stable vector bundle $E$ over a compact Kahler manifold $X$. It is shown that if $E$ is semi-stable, then Donaldson’s functional is bounded from below. This implies that $E$ admits an approximate Hermitian-Einstein structure, generalizing a classic result of Kobayashi for projective manifolds to the Kahler case. As an application some basic properties of semi-stable vector bundles over compact Kahler manifolds are established, such as the fact that semi-stability is preserved under certain exterior and symmetric products.
log–log blow up solutions blow up at exactly m points

Abstract We study the focusing mass-critical nonlinear Schrodinger equation, and construct certain solutions which blow up at exactly m points according to the log–log law.
Periodic points and the measure of maximal entropy of an expanding Thurston map

In this paper, we show that each expanding Thurston map $f : S^2\rightarrow S^2$ has $1+ deg f$ fixed points, counted with appropriate weight, where $ deg f$ denotes the topological degree of the map $f$. We then prove the equidistribution of preimages and of (pre)periodic points with respect to the unique measure of maximal entropy $\mu_f$ for $f$. We also show that $(S^2,f,\mu_f)$ is a factor of the left shift on the set of one-sided infinite sequences with its measure of maximal entropy, in the category of measure-preserving dynamical systems. Finally, we prove that $\mu_f$ is almost surely the weak$^*$ limit of atomic probability measures supported on a random backward orbit of an arbitrary point.
Global sensitivity analysis of frequency band gaps in one-dimensional phononic crystals

Abstract Phononic crystals have been widely employed in many engineering fields, which is because of their unique feature of frequency band gaps. For example, their capability to filter out the incoming elastic waves, which include seismic waves, will have a significant impact on the seismic safety of nuclear infrastructure. To design accurately design the desired frequency band gaps, one must pay attention to how the input parameters and the interaction of the parameters can affect the frequency band gaps. Global sensitivity analysis can decompose the dispersion relationship of the phononic crystals and screen the variance attributed to each of the parameters and the interaction between them. Prior to the application in one-dimensional (1D) phononic crystals, this paper will first review the theory of global sensitivity analysis using variance decomposition (Sobol’ sensitivity analysis). Afterwards, the sensitivity analysis is applied to study a simple mathematical model with three input variables for a better understanding of the concept. Then, the sensitivity analysis is utilized to study the characteristic of the first frequency band gap in 1D phononic crystals with respect to the input parameters. This study reveals the quantified influence of the parameters and their correlation in determining the first frequency band gap. In addition, simple straight-forward design equations based on reduced Sobol’ functions are proposed to estimate easily the first frequency band gap. Finally, the error associated with the proposed design equations is also addressed.
Relaxations for inference in restricted Boltzmann machines

We propose a randomized relax-and-round inference algorithm that samples near-MAP congurations of a binary pairwise Markov random eld. We experiment on MAP inference tasks in several restricted Boltzmann machines. We also use our underlying sampler to estimate the log-partition function of restricted Boltzmann machines and compare against other sampling-based methods.
Gene expression time course clustering with countably infinite hidden Markov models

Most existing approaches to clustering gene expression time course data treat the different time points as independent dimensions and are invariant to permutations, such as reversal, of the experimental time course. Approaches utilizing HMMs have been shown to be helpful in this regard, but are hampered by having to choose model architectures with appropriate complexities. Here we propose for a clustering application an HMM with a countably infinite state space; inference in this model is possible by recasting it in the hierarchical Dirichlet process (HDP) framework (Teh et al. 2006), and hence we call it the HDP-HMM. We show that the infinite model outperforms model selection methods over finite models, and traditional time-independent methods, as measured by a variety of external and internal indices for clustering on two large publicly available data sets. Moreover, we show that the infinite models utilize more hidden states and employ richer architectures (e.g. state-to-state transitions) without the damaging effects of overfitting.
Stochastic Frank-Wolfe methods for nonconvex optimization

We study Frank-Wolfe methods for nonconvex stochastic and finite-sum optimization problems. Frank-Wolfe methods (in the convex case) have gained tremendous recent interest in machine learning and optimization due to their projection-free property and their ability to exploit structured constraints. However, our understanding of these algorithms in the nonconvex setting is fairly limited. In this paper, we propose nonconvex stochastic Frank-Wolfe methods and analyze their convergence properties. Furthermore, for objective functions that decompose into a finite-sum, we leverage ideas from variance reduction for convex optimization to obtain new variance reduced nonconvex Frank-Wolfe methods that have provably faster convergence than the classical Frank-Wolfe method.
Water's Interfacial Hydrogen Bonding Structure Reveals the Effective Strength of Surface-Water Interactions.

The interactions of a hydrophilic surface with water can significantly influence the characteristics of the liquid water interface. In this manuscript, we explore this influence by studying the molecular structure of liquid water at a disordered surface with tunable surface−water interactions. We combine all-atom molecular dynamics simulations with a mean field model of interfacial hydrogen bonding to analyze the effect of surface−water interactions on the structural and energetic properties of the liquid water interface. We find that the molecular structure of water at a weakly interacting (i.e., hydrophobic) surface is resistant to change unless the strength of surface−water interactions is above a certain threshold. We find that below this threshold water’s interfacial structure is homogeneous and insensitive to the details of the disordered surface, however, above this threshold water’s interfacial structure is heterogeneous. Despite this heterogeneity, we demonstrate that the equilibrium distribution...
Efficient Algorithms for Computing a Minimal Homology Basis

Efficient computation of shortest cycles which form a homology basis under \(\mathbb {Z}_2\)-additions in a given simplicial complex \(\mathcal {K}\) has been researched actively in recent years. When the complex \(\mathcal {K}\) is a weighted graph with n vertices and m edges, the problem of computing a shortest (homology) cycle basis is known to be solvable in \(O(m^2n/\log n+ n^2m)\)-time. Several works [1, 2] have addressed the case when the complex \(\mathcal {K}\) is a 2-manifold. The complexity of these algorithms depends on the rank g of the one-dimensional homology group of \(\mathcal {K}\). This rank g has a lower bound of \(\varTheta (n)\), where n denotes the number of simplices in \(\mathcal {K}\), giving an \(O(n^4)\) worst-case time complexity for the algorithms in [1, 2]. This worst-case complexity is improved in [3] to \(O(n^\omega + n^2g^{\omega -1})\) for general simplicial complexes where \(\omega < 2.3728639\) [4] is the matrix multiplication exponent. Taking \(g=\varTheta (n)\), this provides an \(O(n^{\omega +1})\) worst-case algorithm. In this paper, we improve this time complexity. Combining the divide and conquer technique from [5] with the use of annotations from [3], we present an algorithm that runs in \(O(n^\omega +n^2g)\) time giving the first \(O(n^3)\) worst-case algorithm for general complexes. If instead of minimal basis, we settle for an approximate basis, we can improve the running time even further. We show that a 2-approximate minimal homology basis can be computed in \(O(n^{\omega }\sqrt{n \log n})\) expected time. We also study more general measures for defining the minimal basis and identify reasonable conditions on these measures that allow computing a minimal basis efficiently.
Confidence bands for the logistic and probit regression models over intervals

ABSTRACTThis article presents methods for the construction of two-sided and one-sided simultaneous hyperbolic bands for the logistic and probit regression models when the predictor variable is restricted to a given interval. The bands are constructed based on the asymptotic properties of the maximum likelihood estimators. Past articles have considered building two-sided asymptotic confidence bands for the logistic model, such as Piegorsch and Casella (1988). However, the confidence bands given by Piegorsch and Casella are conservative under a single interval restriction, and it is shown in this article that their bands can be sharpened using the methods proposed here. Furthermore, no method has yet appeared in the literature for constructing one-sided confidence bands for the logistic model, and no work has been done for building confidence bands for the probit model, over a limited range of the predictor variable. This article provides methods for computing critical points in these areas.
Arbitrarily small perturbations of Dirichlet Laplacians are quantum unique ergodic

Given an Euclidean domain with very mild regularity properties, we prove that there exist perturbations of the Dirichlet Laplacian of the form $-(I+S_\epsilon)\Delta$ with $\|S_\epsilon\|_{L^2\to L^2}\leq \epsilon$ whose high energy eigenfunctions are quantum uniquely ergodic (QUE). Moreover, if we impose stronger regularity on the domain, the same result holds with $\|S_\epsilon\|_{L^2\to H^\gamma}\leq \epsilon$ for $\gamma>0$ depending on the domain. We also give a proof of a local Weyl law for domains with rough boundaries.
The spectrum of the wavelet Galerkin operator

We give a complete description of spectrum of the wavelet Galerkin operator $$ R_{m_0 ,{\kern 1pt} m_0 } f(z) = \frac{1} {N}\sum\limits_{w^N = z} {|m_0 |^2 (w)f(w),\quad (z \in \mathbb{T})} $$ associated to a low-pass filter m0 and a scale N, in the Banach spaces \(C(\mathbb{T})\) and \(L^P (\mathbb{T}),{\kern 1pt} \,1 \leq p \leq \infty .\)
Distributed Estimation of Graph 4-Profiles

We present a novel distributed algorithm for counting all four-node induced subgraphs in a big graph. These counts, called the 4-profile, describe a graph's connectivity properties and have found several uses ranging from bioinformatics to spam detection. We also study the more complicated problem of estimating the local 4-profiles centered at each vertex of the graph. The local 4-profile embeds every vertex in an 11-dimensional space that characterizes the local geometry of its neighborhood: vertices that connect different clusters will have different local 4-profiles compared to those that are only part of one dense cluster. Our algorithm is a local, distributed message-passing scheme on the graph and computes all the local 4-profiles in parallel. We rely on two novel theoretical contributions: we show that local 4-profiles can be calculated using compressed two-hop information and also establish novel concentration results that show that graphs can be substantially sparsified and still retain good approximation quality for the global 4-profile. We empirically evaluate our algorithm using a distributed GraphLab implementation that we scaled up to 640 cores. We show that our algorithm can compute global and local 4-profiles of graphs with millions of edges in a few minutes, significantly improving upon the previous state of the art.
Evaluating the Contextual Integrity of Privacy Regulation: Parents' IoT Toy Privacy Norms Versus {COPPA}

Increased concern about data privacy has prompted new and updated data protection regulations worldwide. However, there has been no rigorous way to test whether the practices mandated by these regulations actually align with the privacy norms of affected populations. Here, we demonstrate that surveys based on the theory of contextual integrity provide a quantifiable and scalable method for measuring the conformity of specific regulatory provisions to privacy norms. We apply this method to the U.S. Children's Online Privacy Protection Act (COPPA), surveying 195 parents and providing the first data that COPPA's mandates generally align with parents' privacy expectations for Internet-connected "smart" children's toys. Nevertheless, variations in the acceptability of data collection across specific smart toys, information types, parent ages, and other conditions emphasize the importance of detailed contextual factors to privacy norms, which may not be adequately captured by COPPA.
Gender aware spoken language translation applied to English-Arabic

Spoken Language Translation (SLT) is becoming more widely used and becoming a communication tool that helps in crossing language barriers. One of the challenges of SLT is the translation from a language without gender agreement to a language with gender agreement such as English to Arabic. In this paper, we introduce an approach to tackle such limitation by enabling a Neural Machine Translation system to produce gender-aware unbiased translation. We show that NMT system can model the speaker/listener gender information to produce gender-aware translation that reduces the bias effect resulting from having training data dominated by particular gender forms. We propose a method to generate data used in adapting a NMT system to produce gender-aware and unbiased translation. The proposed approach can achieve significant improvement of the translation quality by 2 BLEU points.
Towards on-chip mid infrared photonic aerosol spectroscopy

We propose an on-chip mid-infrared (MIR) photonic spectroscopy platform for aerosol characterization to obtain highly discriminatory information on the chemistry of aerosol particles. Sensing of aerosols is crucial for various environmental, climatic, warfare threat detection, and pulmonary healthcare applications. Currently, chemical characterization of aerosols is performed using FTIR spectroscopy, yielding chemical fingerprinting because most of the vibrational and rotational transitions of chemical molecules fall in the IR range, and Raman spectroscopy. Both techniques use free space bench-top geometries. Here, we propose miniaturized on-chip MIR photonics-based aerosol spectroscopy consisting of a broadband spiral-waveguide sensor that significantly enhances the particle-light interaction to improve sensitivity. The spiral waveguides are made of a chalcogenide glass material (Ge23Sb7S70) which shows a broad transparency over the IR range (1–10 μm). We demonstrate the sensing of N-methyl aniline-based aerosol particles with the device. We anticipate that the sensor will readily complement existing photonic resonator-based particle sizing and counting techniques to develop a unified framework for on-chip integrated photonic aerosol spectroscopy.