cssi/SciSciGPT-SciSciNet huggingface dataset:
How do Personal Real Estate Transactions Affect Productivity and Risk Taking? Evidence from Professional Asset Managers

Housing decisions require intensive attention from households. However, the existing housing literature has not examined the potential connection between costly and time-consuming real estate purchases and the behavior and work productivity of individuals involved in the housing search and acquisition process. In addition, micro evidence on the link between home purchase decisions and the investment/risk choices of households is limited and inconclusive. Our study fills these gaps in the literature by examining the real estate acquisitions of professional asset managers. Overall, we find evidence that major purchases, such as real estate acquisitions, lead to distractions, as evidenced by reduced performance, less active trading, and increased susceptibility to behavioral biases such as the disposition effect. We also find evidence that managers tend to increase the riskiness of their professional portfolios after real estate purchases. This increase in risk is concentrated in cases of purchases of investment properties and purchases using extensive leverage, suggesting consistent risk-taking appetites across personal and professional portfolios. These findings suggest that housing transactions may shed light on the decision making, risk taking, and work productivity of a broad set of homeowners, such as asset managers, corporate executives, and even rank and file employees.
Predicting Local Inversions Using Rectangle Clustering and Representative Rectangle Prediction

As a specific type of structural variation, inversions are enjoying particular traction as a result of their established role in evolution. Using third-generation sequencing technology to predict inversions is growing in interest, but many such methods focus on improving sensitivity, giving rise to either too many false positives or very long running times. In this paper, we propose a new framework for inversion detection based on a combination of two novel theoretical models: rectangle clustering and representative rectangle prediction. This combination can automatically filter out false positive inversion predictions while retaining correct ones, leading to a method that has both high sensitivity and high positive prediction values (PPV). Further, this new framework can run very fast on available data. Our software can be freely obtained at https://github.com/UTbioinf/RigInv .
Nanoscale Chemical Reaction Imaging at the Solid–Liquid Interface via TERS

Not all regions of optical field nanolocalization and enhancement are suitable sites for chemical transformations on plasmonic metals. We illustrate the concept using chemically functionalized monocrystalline gold platelets in aqueous solution imaged using a Au-coated tip-enhanced Raman scattering (TERS) probe. For our proof-of-principle study, we select a model plasmon-driven chemical process, namely, the dimerization of p-nitrothiophenol (NTP) to dimercaptoazobenzene. Consistent with recent observations from our group, we find that TERS maps at vibrational resonances corresponding to NTP trace the optical fields that are maximally enhanced toward the edges of the platelets. Conversely, simultaneously recorded product maps reveal that the dimerization process occurs only at specific sites on our substrate. Given the uniformity of the structures and local optical fields at the edges of the gold platelets, our results suggest that molecular crowding and steric effects play a key role in our case of plasmon-driven NTP dimerization at the gold-water interface.
Catalytic and Enantioselective Route to Medium-Ring Heterocycles. Asymmetric Zirconium-Catalyzed Ethylmagnesation of Seven- and Eight-Membered Rings

A variety of medium-ring heterocycles, prepared efficiently by the Ru-catalyzed diene metathesis method, undergo asymmetric catalytic ethylmagnesation to afford nonracemic unsaturated alcohols and ...
A distinct transcriptional profile in response to endothelial monocyte activating polypeptide II is partially mediated by JAK-STAT3 in murine macrophages

Macrophages are important responders to environmental changes such as secreted factors. Among the secreted factors in injured tissues, the highly conserved endothelial monocyte activating polypepti...
Quark enables semi-reference-based compression of RNA-seq data.

Motivation The past decade has seen an exponential increase in biological sequencing capacity, and there has been a simultaneous effort to help organize and archive some of the vast quantities of sequencing data that are being generated. Although these developments are tremendous from the perspective of maximizing the scientific utility of available data, they come with heavy costs. The storage and transmission of such vast amounts of sequencing data is expensive. Results We present Quark, a semi-reference-based compression tool designed for RNA-seq data. Quark makes use of a reference sequence when encoding reads, but produces a representation that can be decoded independently, without the need for a reference. This allows Quark to achieve markedly better compression rates than existing reference-free schemes, while still relieving the burden of assuming a specific, shared reference sequence between the encoder and decoder. We demonstrate that Quark achieves state-of-the-art compression rates, and that, typically, only a small fraction of the reference sequence must be encoded along with the reads to allow reference-free decompression. Availability and implementation Quark is implemented in C ++11, and is available under a GPLv3 license at www.github.com/COMBINE-lab/quark. Contact rob.patro@cs.stonybrook.edu. Supplementary information Supplementary data are available at Bioinformatics online.
Reactions of ethyl phosphites with β-nitrostyrenes. The role of nitrosoalkenes as intermediates

3-Phenyl-2-substituted-indoles are formed in high yields in the reaction of Ph 2 C=(R)NO 2 (R=H, Me, Ph) with (EtO) 3 P at 150 o C while reaction with (EtO) 2 PO - /(EtO) 2 P(O)H at room temperature forms the aziridines 1 with R=H, Me, Ph. 2,2-Diphenyl-3-substituted-2H-azirines formed by deoxygenation of the Michael-type adducts are postulated as intermediates
Entanglement criteria: quantum and topological

This paper gives a criterion for detecting the entanglement of a quantum state, and uses it to study the relationship between topological and quantum entanglement. It is fundamental to view topological entanglements such as braids as entanglement operators and to associate to them unitary operators that are capable of creating quantum entanglement. The entanglement criterion is used to explore this connection.
On toric orbits in the affine sieve

We give a detailed analysis of a heuristic model for the failure of "saturation" in instances of the Affine Sieve having toral Zariski closure. Based on this model, we formulate precise conjectures on several classical problems of arithmetic interest, and test these against empirical data.
QTLseqr: An R Package for Bulk Segregant Analysis with Next-Generation Sequencing

Next-Generation Sequencing Bulk Segregant Analysis (NGS-BSA) is efficient in detecting quantitative trait loci (QTL). Despite the popularity of NGS-BSA and the R statistical platform, no R packages are currently available for NGS-BSA. We present QTLseqr, an R package for NGS-BSA that identifies QTL using two statistical approaches: QTL-seq and G'. These approaches use a simulation method and a tricube smoothed G statistic, respectively, to identify and assess statistical significance of QTL. QTLseqr can import and filter SNP data, calculate SNP distributions, relative allele frequencies, G' values, and log (-values), enabling identification and plotting of QTL. The source code is available at .
Epitaxial rare-earth superlattices and films

Epitaxial growth of rare-earth superlattices is demonstrated to have opened important new areas of research on magnetic materials. The propagation magnetic order through non-magnetic elements, including its range and anisotropy, has been studied. The importance of magnetostriction in determining the phase diagram is demonstrated by the changes induced by epitaxial clamping. The crystallinity of epitaxial superlattices provides the opportunity to study interfacial magnetism by conventional x-ray and neutron scattering methods.
New proton-ionizable, cesium-selective calix[4]arene-bis(crown-6-ethers) with markedly enhanced extraction efficiency

The first 1,3-alternate calix[4]arene-bis(crown-6-ethers) with a proton-ionizable group located in front of one crown ether cavity are synthesized. Compared with an analog that has no proton-ionizable group, the two new ligands possess markedly higher Cs+ extraction efficiency.
Validation of the British Thoracic Society Severity Criteria for Pediatric Community-acquired Pneumonia.

Background:The British Thoracic Society (BTS) guideline for pediatric community-acquired pneumonia (CAP) outlines severity criteria to guide clinical decision-making. Our objective was to examine the predictive performance of the criteria on the need for hospitalization (NFH) and disposition.Methods
A ketal-tethered RCM strategy toward the synthesis of spiroketal related natural products

An unconventional approach to construct spiroketals and spiroaminals via ring-closing metathesis [RCM] of cyclic ketals and aminals, respectively, is described here. This method possesses a good generality with no loss of stereochemical integrity at the spirocenter under the standard RCM conditions. This approach has been applied to the synthesis of an insect pheromone to demonstrate its synthetic potential, and also to the synthesis of the C11-epi-C22-C23 fragment in spirastrellolide A. Both are proof-of-concept applications to feature a ketal-tethered RCM as an alternative strategy for construction of spiroketals.
Rainbowfish: A Succinct Colored de Bruijn Graph Representation

The colored de Bruijn graph— a variant of the de Bruijn graph which associates each edge (i.e., k-mer) with some set of colors - is an increasingly important combinatorial structure in computational biology. Iqbal et al. demonstrated the utility of this structure for representing and assembling a collection (population) of genomes, and showed how it can be used to accurately detect genetic variants. Muggli et al. introduced VARI, a representation of the colored de Bruijn graph that adopts the BOSS representation for the de Bruijn graph topology and achieves considerable savings in space over Cortex, albeit with some sacrifice in speed. The memory-efficient representation of VARI allows the colored de Bruijn graph to be constructed and analyzed for large datasets, beyond what is possible with Cortex. In this paper, we introduce Rainbowfish, a succinct representation of the color information of the colored de Bruijn graph that reduces the space usage even further. Our representation also uses BOSS to represent the de Bruijn graph, but decomposes the color sets based on an equivalence relation and exploits the inherent skewness in the distribution of these color sets. The Rainbowfish representation is compressed based on the 0th-order entropy of the color sets, which can lead to a significant reduction in the space required to store the relevant information for each edge. In practice, Rainbowfish achieves up to a 20x improvement in space over VARI. Rainbowfish is written in C++11 and is available at https://github.com/COMBINE-lab/rainbowfish.
Synthesis of Glycosyl Azides by the Addition of Phenylselenenyl Azide to Glycals

Abstract The addition of phenylselenenyl azide to glycals is carried out under conditions that give 2-deoxy-2-phenylselenoglycosyl azides. This regiochemistry is opposite to that obtained under free-radical conditions, which are known to produce 2-azido-2-deoxyselenoglycosides. The addition reaction is carried out with phenylselenenyl chloride and sodium azide in dimethylformamide, and is stereoselective for trans addition. Tri-O-benzyl-d-glucal and di-O-benzyl-l-rhamnal each gave two addition products, in which the phenylselenyl and azido groups were either trans diaxial or trans diequatorial. Tri-O-benzyl-d-galactal gave only the trans diaxial addition product.
P(RNCH2CH2)N: efficient catalysts for the cyanosilylation of aldehydes and ketones

Abstract The 1,2-addition of trialkylsilylcyanides to aldehydes and ketones produces the corresponding protected cyanohydrins in good to excellent yields when carried out at 0 °C to room temperature in the presence of catalytic amounts of the nonionic strong base P(RNCH2CH2)N (R = Me, i-Pr) in THF. These catalysts are easily removed from the product by hydrolysis or column filtration through silica gel.
Reactions of Cobalt-Complexed Acetylenic Aldehydes with Chiral (γ-Alkoxyallyl)boranes: Enantioselective Synthesis of 3,4-Dioxy 1,5-Enynes and Stereoselective Entry to Polyfunctional Building Blocks

Toward the goal of developing enantioselective routes to polyfunctional building blocks using Co-based technology, the reactions of (Z)- and (E)-(γ-alkoxyallyl)diisopinocampheylboranes (8, 13) with acetylenic aldehydes and their −Co2(CO)6 complexes (10a−c) have been investigated. Whereas phenylpropynal reacts with (Z)-8 with poor efficiency ( 95% de), and enantioselective (>96% ee) reactions, producing syn-(3,4-dioxy 1,5-enyne)Co2(CO)6 11a−f. Similarly, the newly prepared (E)-boranes 13 also react efficienctly with the complexed aldehydes, affording the corresponding (anti-3,4-dioxy 1,5-enyne)Co2(CO)6 complexes 15a−c with virtually complete diastereo- and enantioselectivity, while phenylpropynal itself reacts inefficiently and with lower enantioselectivity. Oxidative demetalation of the complexed adducts affords the 3,4-dioxy 1,5-enynes 17 with complete maintenance of ste...
polyRAD: Genotype calling with uncertainty from sequencing data in polyploids and diploids

Low or uneven read depth is a common limitation of genotyping-by-sequencing (GBS) and restriction site-associated DNA sequencing (RAD-seq), resulting in high missing data rates, heterozygotes miscalled as homozygotes, and uncertainty of allele copy number in heterozygous polyploids. Bayesian genotype calling can mitigate these issues, but previously has only been implemented in software that requires a reference genome or uses priors that may be inappropriate for the population. Here we present several novel Bayesian algorithms that estimate genotype posterior probabilities, all of which are implemented in a new R package, polyRAD. Appropriate priors can be specified for mapping populations, populations in Hardy-Weinberg equilibrium, or structured populations, and in each case can be informed by genotypes at linked markers. The polyRAD software imports read depth from several existing pipelines, and outputs continuous or discrete numerical genotypes suitable for analyses such as genome-wide association and genomic prediction.
High-throughput purification of solution-phase periodinane mediated oxidation reactions utilizing a novel thiosulfate resin

Abstract A simple and efficient methodology for sequestering byproducts and excess starting reagent from the solution-phase Dess-Martin and Grieco-Dess-Martin periodinane mediated oxidation of primary or secondary alcohols to aldehydes or ketones is described. The periodinane oxidations are carried out under mild conditions followed by treatment with a novel thiosulfate resin which reduces any remaining I(V) and I(III) periodinane species to an I(I) species. Quantitative removal of the I(I) species from the solution is achieved by using a base functionalized resin followed by filtration and evaporation to afford highly pure aldehyde or ketone products. Utilization of this sequestration methodology for periodinane mediated oxidations allows for the high-throughput purification and work-up of parallel reaction chambers and is highly amenable to automation procedures.
Synthesis of classical and nonclassical 2‐amino‐4‐oxo‐6‐benzylthieno‐[2,3‐d]pyrimidines as potential thymidylate synthase inhibitors

A series of seven nonclassical 2-amino-4-oxo-6-substituted thieno[2,3-d]pyrimidines 2-8 and one classical N-[4-(2-amino-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidin-6-ylmethyl)benzoyl]-L-glutamic acid 9 (Table I) were designed as the first in a series of 6-substituted 6-5 fused ring analogs as potential thymidylate synthase (TS) inhibitors and as antitumor agents. The target compounds were synthesized via a Heck coupling of appropriately substituted iodobenzenes and allyl alcohol followed by cyclization using cyanoacetate and sulfur powder to afford substituted thiophenes. The resulting thiophenes were then cyclocondensed with chloroformamidine hydrochloride to afford 2-amino-4-oxo-6-substituted thieno[2,3-d]pyrimidines 2-8 and 26. Hydrolysis of 26 followed by coupling with diethyl L-glutamate afforded 28. The classical analog 9 was obtained by hydrolysis of 28. None of the target compounds inhibited human recombinant thymidylate synthase at 23 μm except 9 for which the IC50 value was 100 μm.
A pH Study on the Chiral Ketone Catalyzed Asymmetric Epoxidation of Hydroxyalkenes

A detailed study shows that the chiral ketone catalyzed asymmetric epoxidations of hydroxyalkenes are highly pH dependent. The lower enantioselectivity obtained at low pH is attributed to the substantial contribution of the direct epoxidation by Oxone. At high pH the epoxidation mediated by chiral ketone out-competes the racemic epoxidation, leading to higher enantioselectivity. The effective substrates include allylic alcohol, homoallylic alcohol, and bishomoallylic alcohol. In most cases, over 90% ee was obtained.
Versican proteolysis predicts immune effector infiltration and post-transplant survival in myeloma

Autologous stem-cell transplantation (ASCT) for multiple myeloma continues to confer benefit in the ‘novel agent’ era [1]. However, most patients relapse, risk stratification is inadequate and opti...
Oxaziridine-Mediated Ring Expansions of Substituted Cyclobutanones: Synthesis of (-)-γ-Amino-β-Hydroxybutyric Acid (GABOB)

Abstract The synthesis and photochemical rearrangement chemistry of oxaziridnes derived from 3-benzyloxy- and 3-phenylcyclobutanone were examined. The oxaziridines were prepared by condensation of the ketones with α-methylbenzylamine followed by oxidation. Photolysis at 254 nm afforded good yields of readily separable lactams; 4-benzyloxy-pyrrolidin-2-one obtained in this way was converted to 4-amino-3-hydroxybutanoic acid (GABOB) by catalytic hydrogenolysis followed by acid hydrolysis.
Remarkable metal-rich ternary chalcogenides Sc14M3Te8 (M = Ru, Os).

In this novel motif, scandium atoms define infinite parallel chains of alternate trans-face-sharing cubes and pairs of square antiprisms in which each polyhedron is also centered by an M atom (M = Ru, Os). These chains are further linked into a three-dimensional structure by Sc(Te2Te4/2) octahedra. Physical property measurements show Sc14Ru3Te8 to be metallic and Pauli-paramagnetic, consistent with the results of extended Huckel band structure calculations. Matrix effects are evident in the dimensions within the chains. The major interactions are Sc-M and Sc-Te.
Pure correlates of exploration and exploitation in the human brain

Balancing exploration and exploitation is a fundamental problem in reinforcement learning. Previous neuroimaging studies of the exploration-exploitation dilemma could not completely disentangle these two processes, making it difficult to unambiguously identify their neural signatures. We overcome this problem using a task in which subjects can either observe (pure exploration) or bet (pure exploitation). Insula and dorsal anterior cingulate cortex showed significantly greater activity on observe trials compared to bet trials, suggesting that these regions play a role in driving exploration. A model-based analysis of task performance suggested that subjects chose to observe until a critical evidence threshold was reached. We observed a neural signature of this evidence accumulation process in the ventromedial prefrontal cortex. These findings support theories positing an important role for anterior cingulate cortex in exploration, while also providing a new perspective on the roles of insula and ventromedial prefrontal cortex.
Recyclable polyisobutylene-supported pyridyl N-oxide allylation catalysts

Abstract Polyisobutylene (PIB) is a useful soluble polymer support that facilitates catalyst recovery and recycling in liquid–liquid biphasic systems because the long polyisobutylene chain confers high phase selective solubility in the nonpolar phase of polar–nonpolar liquid–liquid biphasic systems on groups attached to the polymer’s terminus. This work shows that PIB-supports that are effective with metal catalysts can also facilitate synthesis and use of organocatalysts. This is demonstrated by the use of a PIB-supported pyridyl N -oxide to promote the allylation of several aromatic aldehydes with allyltrichlorosilane. These studies show that a PIB-supported pyridyl N -oxide is a very active recyclable catalyst that promotes the allylation of aromatic aldehydes in yields of up to 99% yield. These PIB-supported pyridyl N -oxide catalysts were recovered in the hexane phase of a hexane/90% EtOH–H 2 O solvent system and were successfully recycled through 5 cycles with little effect on catalyst efficiency.
Preparation of highly porous silica gel from poly(tetramethylene oxide)/silica hybrids

Porous silica gels with high surface area were prepared by calcination of silica/poly(tetramethylene oxide) (PTMO) hybrid network materials. The variation of the surface area of these silica gels with PTMO/silica composition and molecular weight of PTMO was investigated. Surface area analysis showed that for all oligomeric molecular weights of PTMO, high values in the range 700−1000 m2 g-1 could be obtained. The optimum PTMO/TEOS weight ratio was 30−50. Pore size analysis indicated that samples with high surface areas were mesoporous, while samples with low or medium surface areas were microporous. This unusual result was obtained as a consequence of the particle size of the materials, small for the high surface area materials and large for the low surface area materials. The hysteresis in the adsorption−desorption isotherms indicated that the pores were cylindrical in shape.
Generation of N-acyl iminium ions from ionization-rearrangement reactions of N-triflyloxy amides

Abstract N-Triflyloxy amides undergo ionization in refluxing isopropanol to give N-acyliminium ions which can be trapped by addition of allyltrimethylsilane to the reaction mixture. Alternatively they can be converted to N-(isopropoxy)alkyl amides and then back to N-acyliminium ions under a variety of conditions.
Synthetic entries to 6-fluoro-7-substituted indole derivatives

Three practical synthetic entries of functionalized 6-fluoro-7-substituted indole derivatives were developed in connection with the preparation of 7-fluoro-8-substituted-1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetic acid derivatives 11. The first route, which permits group modification about position 8 of the pyranoindole skeleton, employs 2-bromo-3-fluoroaniline (18) as a key intermediate, the preparation of which was achieved by either a novel ortho metalation of 15 or via the intermediacy of 22. The second route utilizes 32 to append a terminally functionalized three carbon side chain onto the indole template and in addition leads to 43 from 40. The third route to the 7-fluoro-8-substituted-pyranoindole skeleton complements route two in that the synthetic pathway exploits 32 in a nucleophilic fashion to construct a terminally functionalized two carbon appendage onto the indole nucleus.
Complex oligosaccharide investigations: Synthesis of an octasaccharide incorporating the dimeric Lex structure of PSGL-1

The synthesis of an octasaccharide containing the dimeric Lex oligosaccharide structure found in PSGL-1 carbohydrate chains is reported. Several approaches were investigated employing regioselective and stereoselective glycosylation procedures, and a novel Lewisx trisaccharide donor, 7, was prepared and utilized as a key intermediate building block in the scheme developed for the construction of octasaccharide 3. Toward the preparation of 7, investigations into the influence of different protecting groups upon the relative reactivities of disaccharide acceptor moieties, 25 or 26, and the fucosyl donors, 10 and 11, were conducted using similar glycosylating conditions. Dramatic differences were noted between the effects of electron-donating and electron-withdrawing groups upon the reactivity of the acceptor hydroxyl. A similar effect upon the glycosylating capability of the donor molecule was, likewise, observed. The repeat use of donor 7 was instrumental in the synthesis of the desired dimeric octasacchar...
Simple Preparations of Tricyclic Orthoamides and Macrocyclic Triamines

Abstract Hexahydropyrimidopyrimidine 3 is condensed with an alkyl ditosylate 4 at room temperature in DME or toluene. The resulting tricyclic salt is reduced with sodium borohydride to provide orthoamides 6a-c. Acidic hydrolysis of these orthoamides gives the corresponding macrocyclic triamines 8a-c in high yield.
Bulk Materials Research for Thermoelectric Power Generation Applications

There are a variety of material systems employing different strategies in an effort to establish a new paradigm for thermoelectric materials performance. One approach is the PGEC, or “phonon-glass electron crystal”, approach were research towards optimization of the electrical properties of very low thermal conductivity materials is key. Other efforts focus on materials that exhibit high power factors via quantum-confinement or nano-scale affects. Still others focus on “engineering” metastable phases that possess properties that are distinct, if not unique, to solid state chemistry. All these approaches are valid and provide a fundamental knowledge base whereby present and future scientific materials discoveries will lead to new technological improvements. This paper focuses on bulk materials, in particular those material systems currently under investigation in the novel materials laboratory at the University of South Florida and the requirements and strategies for their optimization towards improved thermoelectric properties.
A consistent bootstrap procedure for the maximum score estimator

Abstract In this paper we propose a new model-based smoothed bootstrap procedure for making inference on the maximum score estimator of Manski (1975, 1985) and prove its consistency. We provide a set of sufficient conditions for the consistency of any bootstrap procedure in this problem. We compare the finite sample performance of different bootstrap procedures through simulation studies. The results indicate that our proposed smoothed bootstrap outperforms other bootstrap schemes, including the m -out-of- n bootstrap. Additionally, we prove a convergence theorem for triangular arrays of random variables arising from binary choice models, which may be of independent interest.
Probing three-dimensional collective cancer invasion with DIGME

Multicellular pattern formation plays an important role in developmental biology, cancer metastasis and wound healing. While many physical factors have been shown to regulate these multicellular processes, the role of ECM micro-to-meso scale geometry has been poorly understood in 3D collective cancer invasion. We have developed a mechanical-based strategy, Diskoid In Geometrically Micropatterned ECM (DIGME). DIGME allows easy engineering of the shape of 3D tissue organoid, the mesoscale ECM heterogeneity, and the fiber alignment of collagen-based ECM all at the same time. We have employed DIGME to study the 3D invasion of MDA-MB-231 diskoids in engineered collagen matrix. We find that the collective cancer invasion is closely regulated by the micro-to-meso scale geometry of the ECM. We conclude that DIGME provides a simple yet powerful tool to probe 3D dynamics of tissue organoids in physically patterned microenvironments.
Evolution in range expansions with competition at rough boundaries

When a biological population expands into new territory, genetic drift develops an enormous influence on evolution at the propagating front. In such range expansion processes, fluctuations in allele frequencies occur through stochastic spatial wandering of both genetic lineages and the boundaries between genetically segregated sectors. Laboratory experiments on microbial range expansions have shown that this stochastic wandering, transverse to the front, is superdiffusive due to the front's growing roughness, implying much faster loss of genetic diversity than predicted by simple flat front diffusive models. We study the evolutionary consequences of this superdiffusive wandering using two complementary numerical models of range expansions: the stepping stone model, and a new interpretation of the model of directed paths in random media, in the context of a roughening population front. Through these approaches we compute statistics for the times since common ancestry for pairs of individuals with a given spatial separation at the front, and we explore how environmental heterogeneities can locally suppress these superdiffusive fluctuations.
On local Gevrey regularity for Gevrey vectors of subelliptic sums of squares: an elementary proof of a sharp Gevrey Kotake–Narasimhan theorem

We study the regularity of Gevrey vectors for Hormander operators $$\begin{aligned} P = \sum _{j=1}^m X_j^2 + X_0 + c \end{aligned}$$ where the $$X_j$$ are real vector fields and c(x) is a smooth function, all in Gevrey class $$G^{s}.$$ The principal hypothesis is that P satisfies the subelliptic estimate: for some $$\varepsilon >0, \; \exists \,C$$ such that $$\begin{aligned} \Vert v\Vert _{\varepsilon }^2 \le C\left( |(Pv, v)| + \Vert v\Vert _0^2\right) \qquad \forall v\in C_0^\infty . \end{aligned}$$ We prove directly (without the now familiar use of adding a variable t and proving suitable hypoellipticity for $$Q=-D_t^2-P$$ and then, using the hypothesis on the iterates of P on u, constructing a homogeneous solution U for Q whose trace on $$t=0$$ is just u) that for $$s\ge 1,$$ $$G^s(P,\Omega _0) \subset G^{s/\varepsilon }(\Omega _0);$$ that is, $$\begin{aligned}&\forall K\Subset \Omega _0, \;\exists C_K: \Vert P^j u\Vert _{L^2(K)}\le C_K^{j+1} (2j)!^s, \;\forall j\\&\quad \implies \forall K'\Subset \Omega _0, \;\exists \tilde{C}_{K'}:\,\Vert D^\ell u\Vert _{L^2(K')} \le \tilde{C}_{K'}^{\ell +1} \ell !^{s/\varepsilon }, \;\forall \ell . \end{aligned}$$ In other words, Gevrey growth of derivatives of u as measured by iterates of P yields Gevrey regularity for u in a larger Gevrey class. When $$\varepsilon =1,$$ P is elliptic and so we recover the original Kotake–Narasimhan theorem (Kotake and Narasimhan in Bull Soc Math Fr 90(12):449–471, 1962), which has been studied in many other classes, including ultradifferentiable functions (Boiti and Journet in J Pseudo-Differ Oper Appl 8(2):297–317, 2017). We are indebted to M. Derridj for multiple conversations over the years.
Waring’s problem for polynomial rings and the digit sum of exponents

Let $$\overline{\mathbb {F}}_p$$ F ¯ p be the algebraic closure of the finite field $$\mathbb {F}_p$$ F p . In this paper we develop methods to represent arbitrary elements of $$\overline{\mathbb {F}}_p[t]$$ F ¯ p [ t ] as sums of perfect k-th powers for any $$k\in \mathbb {N}$$ k ∈ N relatively prime to p. Using these methods we establish bounds on the necessary number of k-th powers in terms of the sum of the digits of k in its base-p expansion. As one particular application we prove that for any fixed prime $$p > 2$$ p > 2 and any $$\epsilon > 0$$ ϵ > 0 the number of $$(p^r-1)$$ ( p r - 1 ) -th powers required is $$\mathcal {O}\left( r^{(2+\epsilon )\ln (p)}\right) $$ O r ( 2 + ϵ ) ln ( p ) as a function of r.
Hecke modules based on involutions in extended Weyl groups

Let X be the group of weights of a maximal torus of a simply connected semisimple group over C and let W be the Weyl group. The semidirect product W(Q\otimes X/X) is called the extended Weyl group. There is a natural C(v)-algebra H called the extended Hecke algebra with basis indexed by the extended Weyl group which contains the usual Hecke algebra as a subalgebra. We construct an H-module with basis indexed by the involutions in the extended Weyl group. This generalizes a construction of the author and D.Vogan.
Self-triggered time-varying convex optimization

In this paper, we propose a self-triggered algorithm to solve a class of convex optimization problems with time-varying objective functions. It is known that the trajectory of the optimal solution can be asymptotically tracked by a continuous-time state update law. Unfortunately, implementing this requires continuous evaluation of the gradient and the inverse Hessian of the objective function which is not amenable to digital implementation. Alternatively, we draw inspiration from self-triggered control to propose a strategy that autonomously adapts the times at which it makes computations about the objective function, yielding a piece-wise affine state update law. The algorithm does so by predicting the temporal evolution of the gradient using known upper bounds on higher order derivatives of the objective function. Our proposed method guarantees convergence to arbitrarily small neighborhood of the optimal trajectory in finite time and without incurring Zeno behavior. We illustrate our framework with numerical simulations.
Combinatorial methods for the spectral p-norm of hypermatrices

Abstract The spectral p-norm of r-matrices generalizes the spectral 2-norm of 2-matrices. In 1911 Schur gave an upper bound on the spectral 2-norm of 2-matrices, which was extended in 1934 by Hardy, Littlewood, and Polya to r-matrices. Recently, Kolotilina, and independently the author, strengthened Schur's bound for 2-matrices. The main result of this paper extends the latter result to r-matrices, thereby improving the result of Hardy, Littlewood, and Polya. The proof is based on combinatorial concepts like r-partite r-matrix and symmetrant of a matrix, which appear to be instrumental in the study of the spectral p-norm in general. Thus, another application shows that the spectral p-norm and the p-spectral radius of a symmetric nonnegative r-matrix are equal whenever p ≥ r . This result contributes to a classical area of analysis, initiated by Mazur and Orlicz back in 1930. Additionally, a number of bounds are given on the p-spectral radius and the spectral p-norm of r-matrices and r-graphs.
Non-parametric revenue optimization for generalized second price auctions

We present an extensive analysis of the key problem of learning optimal reserve prices for generalized second price auctions. We describe two algorithms for this task: one based on density estimation, and a novel algorithm benefiting from solid theoretical guarantees and with a very favorable running-time complexity of O(nSlog(nS)), where n is the sample size and S the number of slots. Our theoretical guarantees are more favorable than those previously presented in the literature. Additionally, we show that even if bidders do not play at an equilibrium, our second algorithm is still well defined and minimizes a quantity of interest. To our knowledge, this is the first attempt to apply learning algorithms to the problem of reserve price optimization in GSP auctions. Finally, we present the first convergence analysis of empirical equilibrium bidding functions to the unique symmetric Bayesian-Nash equilibrium of a GSP.
Pinned distance problem, slicing measures, and local smoothing estimates

We improve the Peres-Schlag result on pinned distances in sets of a given Hausdorff dimension. In particular, for Euclidean distances, with $$\Delta^y(E) = \{|x-y|:x\in E\},$$ we prove that for any $E, F\subset{\Bbb R}^d$, there exists a probability measure $\mu_F$ on $F$ such that for $\mu_F$-a.e. $y\in F$, (1) $\dim_{\mathcal H}(\Delta^y(E))\geq\beta$ if $\dim_{\mathcal H}(E) + \frac{d-1}{d+1}\dim_{\mathcal H}(F) > d - 1 + \beta$; (2) $\Delta^y(E)$ has positive Lebesgue measure if $\dim_{\mathcal H}(E)+\frac{d-1}{d+1}\dim_{\mathcal H}(F) > d$; (3) $\Delta^y(E)$ has non-empty interior if $\dim_{\mathcal H}(E)+\frac{d-1}{d+1}\dim_{\mathcal H}(F) > d+1$. We also show that in the case when $\dim_{\mathcal H}(E)+\frac{d-1}{d+1}\dim_{\mathcal H}(F)>d$, for $\mu_F$-a.e. $y\in F$, $$ \left\{t\in{\Bbb R} : \dim_{\mathcal H}(\{x\in E:|x-y|=t\}) \geq \dim_{\mathcal H}(E)+\frac{d+1}{d-1}\dim_{\mathcal H}(F)-d \right\} $$ has positive Lebesgue measure. This describes dimensions of slicing subsets of $E$, sliced by spheres centered at $y$. In our proof, local smoothing estimates of Fourier integral operators (FIO) plays a crucial role. In turn, we obtain results on sharpness of local smoothing estimates by constructing geometric counterexamples.
Structure Formulas for Wave Operators Under a Small Scaling Invariant Condition

We obtain structure formulas for the intertwining wave operators of a Schroedinger operator with potential V in R^3. The difference from our previous submission arXiv:1612.07304 lies with the fact that here we impose a scaling invariant condition on the potential, albeit with a smallness requirement.
The Carleson Embedding Theorem with Matrix Weights

In this paper we prove the weighted martingale Carleson Embedding Theorem with matrix weights both in the domain and in the target space.
Limiting the reconstruction capability of generative neural network using negative learning

Generative models are widely used for unsupervised learning with various applications, including data compression and signal restoration. Training methods for such systems focus on the generality of the network given limited amount of training data. A less researched type of techniques concerns generation of only a single type of input. This is useful for applications such as constraint handling, noise reduction and anomaly detection. In this paper we present a technique to limit the generative capability of the network using negative learning. The proposed method searches the solution in the gradient direction for the desired input and in the opposite direction for the undesired input. One of the application can be anomaly detection where the undesired inputs are the anomalous data. We demonstrate the features of the algorithm using MNIST handwritten digit dataset and latter apply the technique to a real-world obstacle detection problem. The results clearly show that the proposed learning technique can significantly improve the performance for anomaly detection.
Lyubeznik numbers in mixed characteristic

This manuscript defines a new family of invariants, analogous to the Lyubeznik numbers, associated to any local ring whose residue field has prime characteristic. In particular, as their nomenclature suggests, these "Lyubeznik numbers in mixed characteristic" are defined for all local rings of mixed characteristic. Some properties similar to those in equal characteristic hold for these new invariants. Notably, the "highest" Lyubeznik number in mixed characteristic is a well-defined notion. Although the Lyubeznik numbers in mixed characteristic and their equal-characteristic counterparts are the same for certain local rings of equal characteristic p>0, we also provide an example where they differ.
Sampling for data freshness optimization: Non-linear age functions

In this paper, we study how to take samples at a data source for improving the freshness of received data samples at a remote receiver. We use non-linear functions of the age of information to measure data freshness, and provide a survey of non-linear age functions and their applications. The sampler design problem is studied to optimize these data freshness metrics, even when there is a sampling rate constraint. This sampling problem is formulated as a constrained Markov decision process (MDP) with a possibly uncountable state space. We present a complete characterization of the optimal solution to this MDP: The optimal sampling policy is a deterministic or randomized threshold policy, where the threshold and the randomization probabilities are characterized based on the optimal objective value of the MDP and the sampling rate constraint. The optimal sampling policy can be computed by bisection search, and the curse of dimensionality is circumvented. These age optimality results hold for (i) general data freshness metrics represented by monotonic functions of the age of information, (ii) general service time distributions of the queueing server, (iii) both continuous-time and discrete-time sampling problems, and (iv) sampling problems both with and without the sampling rate constraint. Numerical results suggest that the optimal sampling policies can be much better than zero-wait sampling and the classic uniform sampling.
The Sato-Tate law for Drinfeld modules

We prove an analogue of the Sato-Tate conjecture for Drinfeld modules. Using ideas of Drinfeld, J.-K. Yu showed that Drinfeld modules satisfy some Sato-Tate law, but did not describe the actual law. More precisely, for a Drinfeld module φ defined over a field L, he constructs a continuous representation ρ∞ : WL → D× of the Weil group of L into a certain division algebra, which encodes the Sato-Tate law. When φ has generic characteristic and L is finitely generated, we shall describe the image of ρ∞ up to commensurability. As an application, we give improved upper bounds for the Drinfeld module analogue of the Lang-Trotter conjecture.
Bounds on the Effective-length of Optimal Codes for Interference Channel with Feedback

In this paper, we investigate the necessity of finite blocklength codes in distributed transmission of independent message sets over channels with feedback. We provide two examples of three user interference channels with feedback where codes with asymptotically large effective lengths are sub-optimal. As a result, we conclude that coded transmission using finite effective length codes is necessary to achieve optimality. We argue that the sub-optimal performance of large effective length codes is due to their inefficiency in preserving the correlation between the inputs to the distributed terminals in the communication system. This correlation is made available by the presence of feedback at the terminals and is used as a means for coordination between them when using finite effective length coding strategies.
Magnetic Avalanches in Molecular Magnets

The reversal of the magnetization of crystals of molecular magnets that have a large spin and high anisotropy barrier generally proceeds below the blocking temperature by quantum tunneling. This is manifested as a series of controlled steps in the hysteresis loops at resonant values of the magnetic field where energy levels on opposite sides of the barrier cross. An abrupt reversal of the magnetic moment of the entire crystal can occur instead by a process commonly referred to as a magnetic avalanche, where the molecular spins reverse along a deflagration front that travels through the sample at subsonic speed. In this chapter, we review experimental results obtained to date for magnetic deflagration in molecular nanomagnets.
Static data structure lower bounds imply rigidity

We show that static data structure lower bounds in the group (linear) model imply semi-explicit lower bounds on matrix rigidity. In particular, we prove that an explicit lower bound of t ≥ ω(log2n) on the cell-probe complexity of linear data structures in the group model, even against arbitrarily small linear space (s= (1+)n), would already imply a semi-explicit (PNP) construction of rigid matrices with significantly better parameters than the current state of art (Alon, Panigrahy and Yekhanin, 2009). Our results further assert that polynomial (t≥ nδ) data structure lower bounds against near-optimal space, would imply super-linear circuit lower bounds for log-depth linear circuits (a four-decade open question). In the succinct space regime (s=n+o(n)), we show that any improvement on current cell-probe lower bounds in the linear model would also imply new rigidity bounds. Our results rely on a new connection between the “inner” and “outer” dimensions of a matrix (Paturi and Pudlak, 2006), and on a new reduction from worst-case to average-case rigidity, which is of independent interest.
A Study of Clustering Techniques and Hierarchical Matrix Formats for Kernel Ridge Regression

We present memory-efficient and scalable algorithms for kernel methods used in machine learning. Using hierarchical matrix approximations for the kernel matrix the memory requirements, the number of floating point operations, and the execution time are drastically reduced compared to standard dense linear algebra routines. We consider both the general H matrix hierarchical format as well as Hierarchically Semi-Separable (HSS) matrices. Furthermore, we investigate the impact of several preprocessing and clustering techniques on the hierarchical matrix compression. Effective clustering of the input leads to a ten-fold increase in efficiency of the compression. The algorithms are implemented using the STRUMPACK solver library. These results confirm that — with correct tuning of the hyperparameters — classification using kernel ridge regression with the compressed matrix does not lose prediction accuracy compared to the exact — not compressed — kernel matrix and that our approach can be extended to O(1M) datasets, for which computation with the full kernel matrix becomes prohibitively expensive. We present numerical experiments in a distributed memory environment up to 1,024 processors of the NERSC's Cori supercomputer using well-known datasets to the machine learning community that range from dimension 8 up to 784.
Variational inference for Monte Carlo objectives

Recent progress in deep latent variable models has largely been driven by the development of flexible and scalable variational inference methods. Variational training of this type involves maximizing a lower bound on the log-likelihood, using samples from the variational posterior to compute the required gradients. Recently, Burda et al. (2016) have derived a tighter lower bound using a multi-sample importance sampling estimate of the likelihood and showed that optimizing it yields models that use more of their capacity and achieve higher likelihoods. This development showed the importance of such multisample objectives and explained the success of several related approaches. We extend the multi-sample approach to discrete latent variables and analyze the difficulty encountered when estimating the gradients involved. We then develop the first unbiased gradient estimator designed for importance-sampled objectives and evaluate it at training generative and structured output prediction models. The resulting estimator, which is based on low-variance per-sample learning signals, is both simpler and more effective than the NVIL estimator (Mnih & Gregor, 2014) proposed for the single-sample variational objective, and is competitive with the currently used biased estimators.
On the Achievability Region of Regenerating Codes for Multiple Erasures

We study the problem of centralized exact repair of multiple failures in distributed storage. We describe constructions that achieve a new set of interior points under exact repair. The constructions build upon the layered code construction by Tian et al in [1], designed for exact repair of single failure. We firstly improve upon the layered construction for general system parameters. Then, we extend the improved construction to support adaptive repair for a flexible number of failures, and a flexible number of helpers. In particular, we prove the optimality of one point on the functional repair tradeoff of multiple failures for some parameters. Finally, considering minimum bandwidth cooperative repair (MBCR) codes as centralized repair codes, we determine explicitly the best achievable region obtained by space-sharing among all known points, including the MBCR point.