cssi/SciSciGPT-SciSciNet huggingface dataset:
Some Extremal Problems for Hereditary Properties of Graphs

Given an infinite hereditary property of graphs $\mathcal{P}$, the principal extremal parameter of $\mathcal{P}$ is the value \[ \pi\left( \mathcal{P}\right) =\lim_{n\rightarrow\infty}\binom{n}{2}^{-1}\max\{e\left( G\right) :\text{ }G\in\mathcal{P}\text{ and }v\left( G\right) =n\}. \] The Erdős-Stone theorem gives $\pi\left( \mathcal{P}\right) $ if $\mathcal{P}$ is monotone, but this result does not apply to hereditary $\mathcal{P}$. Thus, one of the results of this note is to establish $\pi\left( \mathcal{P}\right) $ for any hereditary property $\mathcal{P}.$ Similar questions are studied for the parameter $\lambda^{\left( p\right)}\left( G\right)$, defined for every real number $p\geq1$ and every graph $G$ of order $n$ as \[ \lambda^{\left( p\right) }\left( G\right) =\max_{\left\vert x_{1}\right\vert^{p}\text{ }+\text{ }\cdots\text{ }+\text{ }\left\vert x_{n}\right\vert ^{p} \text{ }=\text{ }1}2\sum_{\{u,v\}\in E\left( G\right) }x_{u}x_{v}. \] It is shown that the limit \[ \lambda^{\left( p\right) }\left( \mathcal{P}\right) =\lim_{n\rightarrow \infty}n^{2/p-2}\max\{\lambda^{\left( p\right) }\left( G\right) :\text{ }G\in \mathcal{P}\text{ and }v\left( G\right) =n\} \] exists for every hereditary property $\mathcal{P}$. A key result of the note is the equality \[ \lambda^{(p)}\left( \mathcal{P}\right) =\pi\left( \mathcal{P}\right) , \] which holds for all $p>1.$ In particular, edge extremal problems and spectral extremal problems for graphs are asymptotically equivalent.
Left-invariant grauert tubes on SU(2)

Let M be a real analytic Riemannian manifold. An adapted complex structure on TM is a complex structure on a neighborhood of the zero section such that the leaves of the Riemann foliation are complex submanifolds. This structure is called entire if it may be extended to the whole of TM. We call such manifolds Grauert tubes, or simply tubes. We consider here the case of M = G a compact connected Lie group with a left-invariant metric, and try to determine for which such metrics the associated tube is entire. It is well-known that the Grauert tube of a bi-invariant metric on a Lie group is entire. The case of the smallest group SU(2) is treated completely, thanks to the complete integrability of the geodesic flow for such a metric, a standard result in classical mechanics. Along the way we find a new obstruction to tubes being entire which is made visible by the complete integrability. (New reference and exposition shortened, 11/17/2017.)
Rainbow Connectivity of Sparse Random Graphs

An edge colored graph G is rainbow edge connected if any two vertices are connected by a path whose edges have distinct colors. The rainbow connectivity of a connected graph G, denoted by rc(G), is the smallest number of colors that are needed in order to make G rainbow connected.
Data Integration and Machine Learning: A Natural Synergy

As data volume and variety have increased, so have the ties between machine learning and data integration become stronger. For machine learning to be effective, one must utilize data from the greatest possible variety of sources; and this is why data integration plays a key role. At the same time machine learning is driving automation in data integration, resulting in overall reduction of integration costs and improved accuracy. This tutorial focuses on three aspects of the synergistic relationship between data integration and machine learning: (1) we survey how state-of-the-art data integration solutions rely on machine learning-based approaches for accurate results and effective human-in-the-loop pipelines, (2) we review how end-to-end machine learning applications rely on data integration to identify accurate, clean, and relevant data for their analytics exercises, and (3) we discuss open research challenges and opportunities that span across data integration and machine learning.
Customer-Base Concentration, Investment, and Profitability: The U.S. Government as a Major Customer

ABSTRACT We examine whether customer-base concentration has a differential impact on profitability for firms contracting with major government customers versus firms contracting with major corporat...
Bean Split Ratio for Dry Bean Canning Quality and Variety Analysis

Splits on canned beans appear in the process of preparation and canning. Researchers are studying how they are influenced by cooking environment and genotype. However, there is no existing method to automatically quantify or to characterize the severity of splits. To solve this, we propose two measures: the Bean Split Ratio (BSR) that quantifies the overall severity of splits, and the Bean Split Histogram (BSH) that characterizes the size distribution of splits. We create a pixel-wise segmentation method to automatically estimate these measures from images. We also present a bean dataset of recombinant inbred lines of two genotypes, use the BSR and BSH to assess canning quality, and explore heritability of these properties.
Ramped thermal analysis for isolating biologically meaningful soil organic matter fractions with distinct residence times

Abstract. In this work, we assess whether or not ramped thermal oxidation coupled with determination of the radiocarbon content of the evolved CO2 can be used to isolate distinct thermal fractions of soil organic matter (SOM) along with direct information on the turnover rate of each thermal fraction. Using a 30-year time series of soil samples from a well-characterized agronomic trial, we found that the incorporation of the bomb spike in atmospheric 14CO2 into thermal fractions of increasing resistance to thermal decomposition could be successfully modeled. With increasing temperature, which is proportional to activation energy, the mean residence time of the thermal fractions increased from 10 to 400 years. Importantly, the first four of five thermal fractions appeared to be a mixture of fast- and increasingly slower-cycling SOM. To further understand the composition of different thermal fractions, stepped pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) experiments were performed at five temperatures ranging from 330 to 735 ∘ C. The Py-GC/MS data showed a reproducible shift in the chemistry of pyrolysis products across the temperature gradient trending from polysaccharides and lipids at low temperature to lignin- and microbe-derived compounds at middle temperatures to aromatic and unknown compounds at the highest temperatures. Integrating the 14C and Py-GC/MS data suggests the organic compounds, with the exception of aromatic moieties likely derived from wildfire, with centennial residence times are not more complex but may be protected from pyrolysis, and likely also from biological mineralization, by interactions with mineral surfaces.
Thick amorphous complexion formation and extreme thermal stability in ternary nanocrystalline Cu-Zr-Hf alloys

Abstract Building on the recent discovery of tough nanocrystalline Cu-Zr alloys with amorphous intergranular films, this paper investigates ternary nanocrystalline Cu-Zr-Hf alloys with a focus on understanding how alloy composition affects the formation of disordered complexions. Binary Cu-Zr and Cu–Hf alloys with similar initial grain sizes were also fabricated for comparison. The thermal stability of the nanocrystalline alloys was evaluated by annealing at 950 °C (>95% of the solidus temperatures), followed by detailed characterization of the grain boundary structure. All of the ternary alloys exhibited exceptional thermal stability comparable to that of the binary Cu-Zr alloy, and remained nanocrystalline even after two weeks of annealing at this extremely high temperature. Despite carbide formation and growth in these alloys during milling and annealing, the thermal stability of the ternary alloys is mainly attributed to the formation of thick amorphous intergranular films at high temperatures. Our results show that ternary alloy compositions have thicker boundary films compared to the binary alloys with similar global dopant concentrations. While it is not required for amorphous complexion formation, this work shows that having at least three elements present at the interface can lead to thicker grain boundary films, which is expected to maximize the previously reported toughening effect.
On the equivalence between graph isomorphism testing and function approximation with GNNs

Graph neural networks (GNNs) have achieved lots of success on graph-structured data. In light of this, there has been increasing interest in studying their representation power. One line of work focuses on the universal approximation of permutation-invariant functions by certain classes of GNNs, and another demonstrates the limitation of GNNs via graph isomorphism tests. Our work connects these two perspectives and proves their equivalence. We further develop a framework of the representation power of GNNs with the language of sigma-algebra, which incorporates both viewpoints. Using this framework, we compare the expressive power of different classes of GNNs as well as other methods on graphs. In particular, we prove that order-2 Graph G-invariant networks fail to distinguish non-isomorphic regular graphs with the same degree. We then extend them to a new architecture, Ring-GNN, which succeeds in distinguishing these graphs as well as for tasks on real-world datasets.
Single-cell imaging reveals unexpected heterogeneity of telomerase reverse transcriptase expression across human cancer cell lines

Telomerase is pathologically reactivated in most human cancers, where it maintains chromosomal telomeres and allows immortalization. Because telomerase reverse transcriptase (TERT) is usually the limiting component for telomerase activation, numerous studies have measured TERT mRNA levels in populations of cells or in tissues. In comparison, little is known about TERT expression at the single-cell and single-molecule level. To address this, we analyzed TERT expression across 10 human cancer lines using single-molecule RNA fluorescent in situ hybridization (FISH) and made several unexpected findings. First, there was substantial cell-to-cell variation in number of transcription sites and ratio of transcription sites to gene copies. Second, previous classification of lines as having monoallelic or biallelic TERT expression was found to be inadequate for capturing the TERT gene expression patterns. Finally, spliced TERT mRNA had primarily nuclear localization in cancer cells and induced pluripotent stem cells (iPSCs), in stark contrast to the expectation that spliced mRNA should be predominantly cytoplasmic. These data reveal unappreciated heterogeneity, complexity, and unconventionality in TERT expression across human cancer cells.
Towards the linear arboricity conjecture

Abstract The linear arboricity of a graph G, denoted by la ( G ) , is the minimum number of edge-disjoint linear forests (i.e. forests in which every connected component is a path) in G whose union covers all the edges of G. A famous conjecture due to Akiyama, Exoo, and Harary from 1981 asserts that la ( G ) ≤ ⌈ ( Δ ( G ) + 1 ) / 2 ⌉ , where Δ ( G ) denotes the maximum degree of G. This conjectured upper bound would be best possible, as is easily seen by taking G to be a regular graph. In this paper, we show that for every graph G, la ( G ) ≤ Δ 2 + O ( Δ 2 / 3 − α ) for some α > 0 , thereby improving the previously best known bound due to Alon and Spencer from 1992. For graphs which are sufficiently good spectral expanders, we give even better bounds. Our proofs of these results further give probabilistic polynomial time algorithms for finding such decompositions into linear forests.
Ending “Too Big To Fail”: Government Promises Versus Investor Perceptions

Can a government credibly promise not to bailout firms whose failure would have major negative systemic consequences? Our analysis of Korea’s 1997–98 crisis suggests an answer: No. Despite a general "no bailout" policy during the crisis, the largest Korean corporate groups—facing severe financial and governance problems—could still borrow heavily from households by issuing bonds at prices implying very low expected default risk. The evidence suggests "too big to fail" beliefs were not eliminated by government promises because investors believed that this policy was not time consistent. Subsequent bailouts confirmed the market view that creditors would be protected.
Recurrent Event Data

Many lifetime data studies involve units that experience multiple-ordered events of the same nature. The resulting data is commonly termed recurrent event data. This article presents some of the important aspects that need to be considered when modeling this type of data. It surveys several of the models that are found in the literature. The models are applied to a real data set for comparative purposes. Keywords: counting processes; effective age; intensity process; mean rate function; recurrent events
Interaction of the westerlies with the Tibetan Plateau in determining the Mei-Yu termination

AbstractThis study explores how the termination of the mei-yu is dynamically linked to the westerlies impinging on the Tibetan Plateau. It is found that the mei-yu stage terminates when the maximum...
Investigating Evaluation of Open-Domain Dialogue Systems With Human Generated Multiple References.

The aim of this paper is to mitigate the shortcomings of automatic evaluation of open-domain dialog systems through multi-reference evaluation. Existing metrics have been shown to correlate poorly with human judgement, particularly in open-domain dialog. One alternative is to collect human annotations for evaluation, which can be expensive and time consuming. To demonstrate the effectiveness of multi-reference evaluation, we augment the test set of DailyDialog with multiple references. A series of experiments show that the use of multiple references results in improved correlation between several automatic metrics and human judgement for both the quality and the diversity of system output.
The l‐Alanosine Gene Cluster Encodes a Pathway for Diazeniumdiolate Biosynthesis

N-Nitroso-containing natural products are bioactive metabolites with antibacterial and anticancer properties. In particular, compounds containing the diazeniumdiolate (N-nitrosohydroxylamine) group display a wide range of bioactivities ranging from cytotoxicity to metal chelation. Despite the importance of this structural motif, knowledge of its biosynthesis is limited. Herein we describe the discovery of a biosynthetic gene cluster in Streptomyces alanosinicus ATCC 15710 responsible for producing the diazeniumdiolate natural product l-alanosine. Gene disruption and stable isotope feeding experiments identified essential biosynthetic genes and revealed the source of the N-nitroso group. Additional biochemical characterization of the biosynthetic enzymes revealed that the non-proteinogenic amino acid l-2,3-diaminopropionic acid (l-Dap) is synthesized and loaded onto a free-standing peptidyl carrier protein (PCP) domain in l-alanosine biosynthesis, which we propose may be a mechanism of handling unstable intermediates generated en route to the diazeniumdiolate. These discoveries will facilitate efforts to determine the biochemistry of diazeniumdiolate formation.
PDE acceleration: a convergence rate analysis and applications to obstacle problems

This paper provides a rigorous convergence rate and complexity analysis for a recently introduced framework, called PDE acceleration, for solving problems in the calculus of variations and explores applications to obstacle problems. PDE acceleration grew out of a variational interpretation of momentum methods, such as Nesterov’s accelerated gradient method and Polyak’s heavy ball method, that views acceleration methods as equations of motion for a generalized Lagrangian action. Its application to convex variational problems yields equations of motion in the form of a damped nonlinear wave equation rather than nonlinear diffusion arising from gradient descent. These accelerated PDEs can be efficiently solved with simple explicit finite difference schemes where acceleration is realized by an improvement in the CFL condition from $$\mathrm{d}t\sim \mathrm{d}x^2$$ for diffusion equations to $$\mathrm{d}t\sim \mathrm{d}x$$ for wave equations. In this paper, we prove a linear convergence rate for PDE acceleration for strongly convex problems, provide a complexity analysis of the discrete scheme, and show how to optimally select the damping parameter for linear problems. We then apply PDE acceleration to solve minimal surface obstacle problems, including double obstacles with forcing, and stochastic homogenization problems with obstacles, obtaining state-of-the-art computational results.
Robust control design for a class of mismatched uncertain nonlinear systems

We consider the robust control design problem for a class of nonlinear uncertain systems. The uncertainty in the system may be due to parameter variations and/or nonlinearity. It may be (possibly fast) time-varying. The system does not satisfy the so-called matching condition. Under a state transformation, which is based on the possible bound of the uncertainty, a robust control scheme can be designed. The control renders the uncertain system practically stable. Furthermore, the uniform ultimate boundedness ball and uniform stability ball can be made arbitrarily small by suitable choice of design parameters.
Modeling mammalian gastrulation with embryonic stem cells

Understanding cell fate patterning and morphogenesis in the mammalian embryo remains a formidable challenge. Recently, in vivo models based on embryonic stem cells (ESCs) have emerged as complementary methods to quantitatively dissect the physical and molecular processes that shape the embryo. Here we review recent developments in using ESCs to create both two- and three-dimensional culture models that shed light on mammalian gastrulation.
Pupil-associated states modulate excitability but not stimulus selectivity in primary auditory cortex.

Cortical neurons vary in their response to repeated stimuli, and some portion of the variability is due to fluctuations in network state. By simultaneously recording pupil and single-neuron activit...
Large-Scale Profiling of RBP-circRNA Interactions from Public CLIP-Seq Datasets

Circular RNAs are a special type of RNA that has recently attracted a lot of research interest in studying its formation and function. RNA binding proteins (RBPs) that bind circRNAs are important in these processes, but have been relatively less studied. CLIP-Seq technology has been invented and applied to profile RBP-RNA interactions on the genome-wide scale. While mRNAs are usually the focus of CLIP-Seq experiments, RBP-circRNA interactions could also be identified through specialized analysis of CLIP-Seq datasets. However, many technical difficulties are involved in this process, such as the usually short read length of CLIP-Seq reads. In this study, we created a pipeline called Clirc specialized for profiling circRNAs in CLIP-Seq data and analyzing the characteristics of RBP-circRNA interactions. In conclusion, to our knowledge, this is one of the first studies to investigate circRNAs and their binding partners through repurposing CLIP-Seq datasets, and we hope our work will become a valuable resource for future studies into the biogenesis and function of circRNAs.
Prescribing inner parts of derivatives of inner functions

Let ℐ be the set of inner functions whose derivative lies in the Nevanlinna class. We show that up to a post-composition with a Mobius transformation, an inner function F ∈ ℐ is uniquely determined by the inner part of its derivative. We also characterize inner functions which can be represented as Inn F′ for some F ∈ ℐ in terms of the associated singular measure, namely, it must live on a countable union of Beurling–Carleson sets. This answers a question raised by K. Dyakonov.
Identifying Heteroprotein Complexes in the Nuclear Envelope.

Abstract The nucleus is delineated by the nuclear envelope (NE), which is a double membrane barrier composed of the inner and outer nuclear membranes as well as a ∼40-nm wide lumen. In addition to its barrier function, the NE acts as a critical signaling node for a variety of cellular processes, which are mediated by protein complexes within this subcellular compartment. Although fluorescence fluctuation spectroscopy is a powerful tool for characterizing protein complexes in living cells, it was recently demonstrated that conventional fluorescence fluctuation spectroscopy methods are not suitable for applications in the NE because of the presence of slow nuclear membrane undulations. We previously addressed this challenge by developing time-shifted mean-segmented Q (tsMSQ) analysis and applied it to successfully characterize protein homo-oligomerization in the NE. However, many NE complexes, such as the linker of the nucleoskeleton and cytoskeleton complex, are formed by heterotypic interactions, which single-color tsMSQ is unable to characterize. Here, we describe the development of dual-color (DC) tsMSQ to analyze NE heteroprotein complexes built from proteins that carry two spectrally distinct fluorescent labels. Experiments performed on model systems demonstrate that DC tsMSQ properly identifies heteroprotein complexes and their stoichiometry in the NE by accounting for spectral cross talk and local volume fluctuations. Finally, we applied DC tsMSQ to study the assembly of the linker of the nucleoskeleton and cytoskeleton complex, a heteroprotein complex composed of Klarsicht/ANC-1/SYNE homology and Sad1/UNC-84 (SUN) proteins, in the NE of living cells. Using DC tsMSQ, we demonstrate the ability of the SUN protein SUN2 and the Klarsicht/ANC-1/SYNE homology protein nesprin-2 to form a heterocomplex in vivo. Our results are consistent with previously published in vitro studies and demonstrate the utility of the DC tsMSQ technique for characterizing NE heteroprotein complexes.
Real effects of governmental accounting standards: Evidence from GASB statement No. 53 – Accounting and financial reporting for derivative instruments

Abstract GASB Statement No. 53, Accounting and Financial Reporting for Derivative Instruments, (GASB 53) significantly altered U.S. governmental sector accounting of derivative instruments by mandating the recognition of hitherto off-balance sheet derivative instruments in the government-wide statement of net assets and requiring that ineffective hedges be clearly identified. These requirements have an unfavorable financial statement impact for municipalities with net negative fair value derivative positions and municipalities holding ineffective hedges. Using a hand-collected, comprehensive dataset of municipal derivatives, we examine whether the level of U.S. municipal derivative holdings changed following the adoption of GASB 53. Consistent with GASB 53 affecting municipal officials’ derivative decisions, we find a significant post-GASB 53 reduction in derivative holdings for municipalities with net negative fair value derivative positions and ineffective hedges. Our findings suggest that governmental accounting regulations could affect real decisions of municipal officials and therefore could potentially have public policy implications beyond the provision of information to stakeholders.
Analyzing client behavior in a syringe exchange program

Multiple syringe exchange programs serve the Chicago metropolitan area, providing support for drug users to help prevent infectious diseases. Using data from one program over a ten-year period, we ...
Increased Adenine Nucleotide Degradation in Skeletal Muscle Atrophy

Adenine nucleotides (AdNs: ATP, ADP, AMP) are essential biological compounds that facilitate many necessary cellular processes by providing chemical energy, mediating intracellular signaling, and regulating protein metabolism and solubilization. A dramatic reduction in total AdNs is observed in atrophic skeletal muscle across numerous disease states and conditions, such as cancer, diabetes, chronic kidney disease, heart failure, COPD, sepsis, muscular dystrophy, denervation, disuse, and sarcopenia. The reduced AdNs in atrophic skeletal muscle are accompanied by increased expression/activities of AdN degrading enzymes and the accumulation of degradation products (IMP, hypoxanthine, xanthine, uric acid), suggesting that the lower AdN content is largely the result of increased nucleotide degradation. Furthermore, this characteristic decrease of AdNs suggests that increased nucleotide degradation contributes to the general pathophysiology of skeletal muscle atrophy. In view of the numerous energetic, and non-energetic, roles of AdNs in skeletal muscle, investigations into the physiological consequences of AdN degradation may provide valuable insight into the mechanisms of muscle atrophy.
Constrained synthesis from component libraries

Synthesis from component libraries is the problem of building a network of components from a given library, such that the network realizes a given specification. This problem is undecidable in general. It becomes decidable if we impose a bound on the number of chosen components. However, the bounded problem remains computationally hard and brute-force approaches do not scale. In this paper we study scalable methods for solving the problem of bounded synthesis from libraries, proposing a solution based on the CounterExample-Guided Inductive Synthesis paradigm. Although our synthesis algorithm does not assume a specific formalism a priori, we present a parallel implementation which instantiates components defined as Linear Temporal Logic-based Assume/Guarantee Contracts. We show the potential of our approach and evaluate our implementation by applying it to an industrial case study.
Directed aging, memory, and nature’s greed

Disordered materials are often out of equilibrium and evolve very slowly in a rugged and tortuous energy landscape. This slow evolution, referred to as aging, is deemed undesirable as it often leads to material degradation. However, we show that aging also encodes a memory of the stresses imposed during preparation. Because of inhomogeneous local stresses, the material itself decides how to evolve by modifying stressed regions differently from those under less stress. Because material evolution occurs in response to stresses, aging can be "directed" to produce sought-after responses and unusual functionalities that do not inherently exist. Aging obeys a natural "greedy algorithm" as, at each instant, the material simply follows the path of most rapid and accessible relaxation. Our experiments and simulations illustrate directed aging in examples in which the material's elasticity transforms as desired because of an imposed deformation.
Secure Communication Over Interference Channel: To Jam or not to Jam?

We consider a secure communication over a two-user Gaussian interference channel, where each transmitter sends a confidential message to its legitimate receiver. For this setting, we identify a regime where the simple scheme of using Gaussian wiretap codebook at each transmitter (without cooperative jamming) and treating interference as noise at each intended receiver (in short, GWC-TIN scheme) achieves the optimal secure sum capacity to within a constant gap. For the symmetric case, this simple scheme is optimal when the interference-to-signal ratio (all link strengths in decibel scale) is no more than 2/3. However, when the ratio is more than 2/3, we show that this simple scheme is not optimal anymore and a scheme with cooperative jamming is proposed to achieve the optimal secure sum generalized degrees-of-freedom (GDoF). Specifically, for the symmetric case, we complete the optimal secure sum GDoF characterization for all the interference regimes, for almost all channel gains (except for a set of channel gains of measure zero).
Edge expansion and spectral gap of nonnegative matrices

The classic graphical Cheeger inequalities state that if M is an n × n symmetric doubly stochastic matrix, then [MATH HERE] where [MATH HERE] is the edge expansion of M, and λ2(M) is the second largest eigenvalue of M. We study the relationship between ϕ(A) and the spectral gap 1 − Re λ2(A) for any doubly stochastic matrix A (not necessarily symmetric), where λ2(A) is a nontrivial eigenvalue of A with maximum real part. Fiedler showed that the upper bound on ϕ(A) is unaffected, i.e., [MATH HERE]. With regards to the lower bound on ϕ(A), there are known constructions with [MATH HERE] indicating that at least a mild dependence on n is necessary to lower bound ϕ(A). In our first result, we provide an exponentially better construction of n X n doubly stochastic matrices An, for which [MATH HERE] In fact, all nontrivial eigenvalues of our matrices are 0, even though the matrices are highly nonexpanding. We further show that this bound is in the correct range (up to the exponent of n), by showing that for any doubly stochastic matrix A, [MATH HERE] As a consequence, unlike the symmetric case, there is a (necessary) loss of a factor of nα for 1/2 ≤ α ≤ 1 in lower bounding ϕ by the spectral gap in the nonsymmetric setting. Our second result extends these bounds to general matrices R with nonnegative entries, to obtain a two-sided gapped refinement of the Perron-Frobenius theorem. Recall from the Perron-Frobenius theorem that for such R, there is a nonnegative eigenvalue r such that all eigenvalues of R lie within the closed disk of radius r about 0. Further, if R is irreducible, which means ϕ(R) > 0 (for suitably defined ϕ), then r is positive and all other eigenvalues lie within the open disk, so (with eigenvalues sorted by real part), Re λ2(R) r. An extension of Fiedler's result provides an upper bound and our result provides the corresponding lower bound on ϕ(R) in terms of r − Re λ2(R), obtaining a two-sided quantitative version of the Perron-Frobenius theorem.
Visual and Endocrine Recovery following Conservative and Surgical Treatment of Pituitary Apoplexy: A Meta-analysis

Background Pituitary apoplexy (PA) can manifest with visual and endocrine defects. The literature lacks strong support for either surgical or conservative management with respect to symptomatic improvement of these deficits. This meta-analysis compared visual and endocrine outcomes in conservative and surgical treatment of PA. Methods A systematic literature search was performed in PubMed, Cochrane, and Ovid MEDLINE for articles published between 1988 and 2018. Recovery outcomes were binarized, such that complete and partial improvements were combined as “improvement.” Primary outcome variables evaluated via a binary random-effects model were improvements in endocrine dysfunction, visual field and acuity deficits, and ophthalmoplegia or ocular nerve palsy. Results Of 483 published articles, 14 studies comprising 457 cases (259 surgical treatments and 198 conservative treatments) were included. On initial examination, 58% of patients had endocrine dysfunction, 37% had visual acuity or field deficit, and 47% had ophthalmoplegia or ocular nerve palsy. Evaluation of outcomes for surgically and conservatively treated patients yielded odds ratios of 0.609 (95% confidence interval [CI], 0.199–1.859; P = 0.383), 0.763 (95% CI, 0.307–2.374; P = 0.763), 1.167 (95% CI, 0.433–3.146; P = 0.760), and 0.801 (95% CI, 0.305–2.105; P = 0.653) for improvements in endocrine dysfunction, visual acuity dysfunction, visual field dysfunction, and ophthalmoplegia or ocular nerve palsy. Conclusions Both surgical intervention and conservative management of PA can lead to visual and endocrine recovery, although the management decision may heavily rely on severity of initial deficits. Treatment of PA can be multifaceted and tailored to the individual case and clinical judgment. Further investigation into appropriate intervention based on longitudinal outcome data is warranted.
eKTELO: A Framework for Defining Differentially Private Computations

The adoption of differential privacy is growing, but the complexity of designing private, efficient, and accurate algorithms is still high. We propose a novel programming framework and system, eKTELO for implementing both existing and new privacy algorithms. For the task of answering linear counting queries, we show that nearly all existing algorithms can be composed from operators, each conforming to one of a small number of operator classes. While past programming frameworks have helped to ensure the privacy of programs, the novelty of our framework is its significant support for authoring accurate and efficient (as well as private) programs. After describing the design and architecture of the eKTELO system, we show that eKTELO is expressive, allows for safer implementations through code reuse, and allows both privacy novices and experts to easily design algorithms. We provide a number of novel implementation techniques to support the generality and scalability of eKTELO operators. These include methods to automatically compute lossless reductions of the data representation, implicit matrices that avoid materialized state but still support computations, and iterative inference implementations that generalize techniques from the privacy literature. We demonstrate the utility of eKTELO by designing several new state-of-the-art algorithms, most of which result from simple re-combinations of operators defined in the framework. We study the accuracy and scalability of eKTELO plans in a thorough empirical evaluation.
Mobile Brain/Body Imaging of cognitive-motor impairment in multiple sclerosis: Deriving EEG-based neuro-markers during a dual-task walking study.

Abstract Objective Individuals with a diagnosis of multiple sclerosis (MS) often present with cognitive and motor deficits, and thus the ability to perform tasks that rely on both domains may be particularly impaired. Yet, dual-task walking studies yield mixed results. Individual variance in the ability to cope with brain insult and mobilize additional brain resources may contribute to mixed findings. Methods To test this hypothesis, we acquired event-related potentials (ERP) in individuals with MS and healthy controls (HCs) performing a Go/NoGo task while sitting (i.e., single task) or walking (i.e., dual-task) and looked at the relationship between task related modulation of the brain response and performance. Results On the Go/NoGo task the MS group showed dual-task costs when walking, whereas HCs showed a dual-task benefit. Further, whereas the HC group showed modulation of the brain response as a function of task load, this was not the case in the MS group. Analysis for the pooled sample revealed a positive correlation between load-related ERP effects and dual-task performance. Conclusions These data suggest a neurophysiological marker of cognitive-motor dysfunction in MS. Significance Understanding neural processes underlying dual-task walking will help identify objective brain measurements of real-world issues and may improve assessment of MS.
On degenerate sections of vector bundles

We consider the locus of sections of a vector bundle on a projective scheme that vanish in higher dimension than expected. We will find the largest components of this locus asymptotically, after applying a high enough twist to the vector bundle. We will also give an interpretation in terms of a limit in the Grothendieck ring of varieties.
Differentiation of human colon tissue in culture: Effects of calcium on trans-epithelial electrical resistance and tissue cohesive properties

Background and aims Human colonoid cultures maintained under low-calcium (0.25 mM) conditions undergo differentiation spontaneously and, concomitantly, express a high level of tight junction proteins, but not desmosomal proteins. When calcium is included to a final concentration of 1.5–3.0 mM (provided either as a single agent or as a combination of calcium and additional minerals), there is little change in tight junction protein expression but a strong up-regulation of desmosomal proteins and an increase in desmosome formation. The aim of this study was to assess the functional consequences of calcium-mediated differences in barrier protein expression. Methods Human colonoid-derived epithelial cells were interrogated in transwell culture under low- or high-calcium conditions for monolayer integrity and ion permeability by measuring trans-epithelial electrical resistance (TEER) across the confluent monolayer. Colonoid cohesiveness was assessed in parallel. Results TEER values were high in the low-calcium environment but increased in response to calcium. In addition, colonoid cohesiveness increased substantially with calcium supplementation. In both assays, the response to multi-mineral intervention was greater than the response to calcium alone. Consistent with these findings, several components of tight junctions were expressed at 0.25 mM calcium but these did not increase substantially with supplementation. Cadherin-17 and desmoglein-2, in contrast, were weakly-expressed under low calcium conditions but increased with intervention. Conclusions These findings indicate that low ambient calcium levels are sufficient to support the formation of a permeability barrier in the colonic epithelium. Higher calcium levels promote tissue cohesion and enhance barrier function. These findings may help explain how an adequate calcium intake contributes to colonic health by improving barrier function, even though there is little change in colonic histological features over a wide range of calcium intake levels.
Peers’ parents and educational attainment: The exposure effect

Abstract This paper discusses the ‘exposure effect’ in child development by investigating the extent to which the educational background of peers’ parents is related to a child’s future college attainment. I analyze the friendship networks of a nationally representative sample of high-school students in the US. To address endogenous friendship formation, I adopt two distinct strategies: a selection correction approach and exploiting within-school cohort variations in parental compositions. I find that peers’ academic performance and other observed characteristics, with a rich set of control variables and network fixed effect, do not fully explain the spillover from peers’ parents of the same gender. Effects are more prominent for students with a disadvantaged background - less-educated parents, single-mother households, and less caring fathers. Suggestive evidence is provided to support the role model effect as a plausible channel.
Deep Sequencing Reveals Compartmentalized HIV-1 in the Semen of Men with and without Sexually Transmitted Infection-Associated Urethritis.

Concurrent sexually transmitted infections (STI) can increase the probability of HIV-1 transmission primarily by increasing the viral load present in semen. In this study, we explored the relationship of HIV-1 in blood and seminal plasma in the presence and absence of urethritis and after treatment of the concurrent STI. Primer ID deep sequencing of the V1/V3 region of the HIV-1 env gene was done for paired blood and semen samples from antiretroviral therapy (ART)-naive men living in Malawi with (n = 19) and without (n = 5) STI-associated urethritis; for a subset of samples, full-length env genes were generated for sequence analysis and to test entry phenotype. Cytokine concentrations in the blood and semen were also measured, and a reduction in the levels of proinflammatory cytokines was observed following STI treatment. We observed no difference in the prevalence of diverse compartmentalized semen-derived lineages in men with or without STI-associated urethritis, and these viral populations were largely stable during STI treatment. Clonal amplification of one or a few viral sequences accounted for nearly 50% of the viral population, indicating a recent bottleneck followed by limited viral replication. We conclude that the male genital tract is a site where virus can be brought in from the blood, where localized sustained replication can occur, and where specific genotypes can be amplified, perhaps initially by cellular proliferation but further by limited viral replication.IMPORTANCE HIV-1 infection is a sexually transmitted infection that coexists with other STI. Here, we examined the impact of a concurrent STI resulting in urethritis on the HIV-1 population within the male genital tract. We found that viral populations remain largely stable even with treatment of the STI. These results show that viral populations within the male genital tract are defined by factors beyond transient inflammation associated with a concurrent STI.
OAT: Attesting Operation Integrity of Embedded Devices

Due to the wide adoption of IoT/CPS systems, embedded devices (IoT frontends) become increasingly connected and mission-critical, which in turn has attracted advanced attacks (e.g., control-flow hijacks and data-only attacks). Unfortunately, IoT backends (e.g., remote controllers or in-cloud services) are unable to detect if such attacks have happened while receiving data, service requests, or operation status from IoT devices (remotely deployed embedded devices). As a result, currently, IoT backends are forced to blindly trust the IoT devices that they interact with.To fill this void, we first formulate a new security property for embedded devices, called "Operation Execution Integrity" or OEI. We then design and build a system, OAT, that enables remote OEI attestation for ARM-based bare-metal embedded devices. Our formulation of OEI captures the integrity of both control flow and critical data involved in an operation execution. Therefore, satisfying OEI entails that an operation execution is free of unexpected control and data manipulations, which existing attestation methods cannot check. Our design of OAT strikes a balance between prover’s constraints (embedded devices’ limited computing power and storage) and verifier’s requirements (complete verifiability and forensic assistance). OAT uses a new control-flow measurement scheme, which enables lightweight and space-efficient collection of measurements (97% space reduction from the trace-based approach). OAT performs the remote control-flow verification through abstract execution, which is fast and deterministic. OAT also features lightweight integrity checking for critical data (74% less instrumentation needed than previous work). Our security analysis shows that OAT allows remote verifiers or IoT backends to detect both controlflow hijacks and data-only attacks that affect the execution of operations on IoT devices. In our evaluation using real embedded programs, OAT incurs a runtime overhead of 2.7%.
Allocative Efficiency in Online Auctions: Improving the Performance of Multiple Online Auctions Via Seek-and-Protect Agents

Much of the prominent literature describing behavior in eBay‐like marketplaces emphasizes the successful use of “sniping” agents that wait until the last moments of an auction to bid (truthfully) on behalf of a human user. These agents fare well against “naive” agents (typically assumed to be those who bid incrementally on the most profitable open auction) who do not get the chance to respond to the snipe‐bid placed in the final seconds. This reasoning, however, tends to ignore the effect of the poor coordination that occurs as more and more players attempt the sniping agent strategy, thereby raising prices above their minimum possible competitive equilibrium levels. Using proprietary data purchased from eBay, encompassing all bids submitted on four specific product types over a 3‐month period, we analyze the allocative efficiency, price, and bidder surplus using a software agent and compare this to the historical performance. After showing a significant amount of “money left on the table” in the historical record, we proceed to demonstrate how bidders can significantly improve their surplus (i.e., observed profit) by adopting a “seek‐and‐protect” agent. If bidders go further and implement sequential‐auction shading strategies, they can incrementally improve their surplus, but sometimes at the expense of allocative efficiency. Acknowledging that each bidder’s time window of interest is inherently unobservable, we vary the length of bidders’ consumption windows and find similar results.
Muscarinic Acetylcholine Receptors

Muscarinic acetylcholine receptors are members of the G-protein-coupled receptor superfamily. There are five genes encoding the muscarinic receptors, which are expressed to different extents in a variety of tissues, including cardiac and smooth muscle, secretory glands, and neurons and glial cells in the central and peripheral nervous systems. Muscarinic receptors regulate the activity of enzymes such as adenylyl cyclase and phospholipase C which produce intracellular second messengers, and also regulate the activity of ion channels. Muscarinic receptors regulate a variety of physiological processes.
Capital Markets Integration, Volatility, and Persistence

Abstract This paper shows that volatility induces adverse first-order welfare effects in countries excluded from the global capital market. This result is illustrated in a model characterized by gains from a greater division of activities, where shocks are persistent. We show that non-linearities attributed to financial autarky explain the adverse welfare effects of volatility. We identify the parameters determining the magnitude of the loss — it is proportional to the autocorrelation of shocks, to volatility (as measured by the standard deviation of shocks), and to the degree of product differentiation (as measured by the substitutability among intermediate products).
A uniform approach to inductive posets and inductive closure

Abstract The definition scheme, “A poset P is Z-inductive if it has a subposet B of Z-compact lements such that for every element of p of P there is a Z-set S in B such that p = ⨆S , becomes meaningful when we replace the symbol of Z by such adjectives as “sirected”, “chain”, “pairwise compatible”, “singleton”, etc. Furthermore, several theorems have been proved that seem to differ only in their instantiations of Z. A simialr phenomena occurs when we comsider concepts such as Z-completeness of Z-comtinuity. This suggests that in all these different cases we are really talking about Z same thing. In this paper we show that this is indeed the case by abstracting out the essential common properties of the different instantiations of Z and proving common theorems within the resulting abstract framework.
Coordinatizing Data With Lens Spaces and Persistent Cohomology

We introduce here a framework to construct coordinates in \emph{finite} Lens spaces for data with nontrivial 1-dimensional $\mathbb{Z}_q$ persistent cohomology, $q\geq 3$. Said coordinates are defined on an open neighborhood of the data, yet constructed with only a small subset of landmarks. We also introduce a dimensionality reduction scheme in $S^{2n-1}/\mathbb{Z}_q$ (Lens-PCA: $\mathsf{LPCA}$), and demonstrate the efficacy of the pipeline $PH^1(\;\cdot\; ; \mathbb{Z}_q)$ class $\Rightarrow$ $S^{2n-1}/\mathbb{Z}_q$ coordinates $\Rightarrow$ $\mathsf{LPCA}$, for nonlinear (topological) dimensionality reduction.
The American frontier: Technology versus immigration

How important was international immigration for the US and its demography during the nineteenth century? This paper investigates, quantitatively, its effect on the westward movement of population and the regional and secular changes in fertility. Beside immigration, two alternative forces are considered: technological progress and the land policy (the Homestead Act). An optimal growth model with endogenous fertility and migration is calibrated, and counterfactual experiments reveal that the main driving forces were productivity growth and the declining cost of transportation. International immigration played a lesser role.