cssi/SciSciGPT-SciSciNet huggingface dataset:
External optimal control of fractional parabolic PDEs

In [Antil et al. Inverse Probl. 35 (2019) 084003.] we introduced a new notion of optimal control and source identification (inverse) problems where we allow the control/source to be outside the domain where the fractional elliptic PDE is fulfilled. The current work extends this previous work to the parabolic case. Several new mathematical tools have been developed to handle the parabolic problem. We tackle the Dirichlet, Neumann and Robin cases. The need for these novel optimal control concepts stems from the fact that the classical PDE models only allow placing the control/source either on the boundary or in the interior where the PDE is satisfied. However, the nonlocal behavior of the fractional operator now allows placing the control/source in the exterior. We introduce the notions of weak and very-weak solutions to the fractional parabolic Dirichlet problem. We present an approach on how to approximate the fractional parabolic Dirichlet solutions by the fractional parabolic Robin solutions (with convergence rates). A complete analysis for the Dirichlet and Robin optimal control problems has been discussed. The numerical examples confirm our theoretical findings and further illustrate the potential benefits of nonlocal models over the local ones.
Nucleocytoplasmic Proteomic Analysis Uncovers eRF1 and Nonsense-Mediated Decay as Modifiers of ALS/FTD C9orf72 Toxicity.

Summary The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is a hexanucleotide repeat expansion in C9orf72 (C9-HRE). While RNA and dipeptide repeats produced by C9-HRE disrupt nucleocytoplasmic transport, the proteins that become redistributed remain unknown. Here, we utilized subcellular fractionation coupled with tandem mass spectrometry and identified 126 proteins, enriched for protein translation and RNA metabolism pathways, which collectively drive a shift toward a more cytosolic proteome in C9-HRE cells. Among these was eRF1, which regulates translation termination and nonsense-mediated decay (NMD). eRF1 accumulates within elaborate nuclear envelope invaginations in patient induced pluripotent stem cell (iPSC) neurons and postmortem tissue and mediates a protective shift from protein translation to NMD-dependent mRNA degradation. Overexpression of eRF1 and the NMD driver UPF1 ameliorate C9-HRE toxicity in vivo. Our findings provide a resource for proteome-wide nucleocytoplasmic alterations across neurodegeneration-associated repeat expansion mutations and highlight eRF1 and NMD as therapeutic targets in C9orf72-associated ALS and/or FTD.
Psychedelics and Psychedelic-Assisted Psychotherapy

Objective:The authors provide an evidenced-based summary of the literature on the clinical application of psychedelic drugs in psychiatric disorders.Methods:Searches of PubMed and PsycINFO via Ovid...
A Live-Cell Screen for Altered Erk Dynamics Reveals Principles of Proliferative Control.

Summary Complex, time-varying responses have been observed widely in cell signaling, but how specific dynamics are generated or regulated is largely unknown. One major obstacle has been that high-throughput screens are typically incompatible with the live-cell assays used to monitor dynamics. Here, we address this challenge by screening a library of 429 kinase inhibitors and monitoring extracellular-regulated kinase (Erk) activity over 5 h in more than 80,000 single primary mouse keratinocytes. Our screen reveals both known and uncharacterized modulators of Erk dynamics, including inhibitors of non-epidermal growth factor receptor (EGFR) receptor tyrosine kinases (RTKs) that increase Erk pulse frequency and overall activity. Using drug treatment and direct optogenetic control, we demonstrate that drug-induced changes to Erk dynamics alter the conditions under which cells proliferate. Our work opens the door to high-throughput screens using live-cell biosensors and reveals that cell proliferation integrates information from Erk dynamics as well as additional permissive cues.
Demystifying airline syncope

Syncope forms a major part of medical in-flight emergencies contributing one-in-four in-flight medical events accounting to 70% of flight diversions. In such patients, it is important to elucidate the pathophysiology of syncope prior to diversion. Postural hypotension is the most common etiology of in-flight syncopal events. However, individuals without any underlying autonomic dysfunction can still experience syncope from hypoxia also known as airline syncope. Initial steps in managing such patients include positioning followed by the airway, breathing and circulation of resuscitation. These interventions need to be in close coordination with ground control to determine decision for flight diversion. Interventions which have been tried for prevention include mental challenge and increased salt and fluid intake. The current paper enhances the understanding of airline syncope by summarizing the associated pathophysiologic mechanisms and the management medical personnel can initiate with limited resources.
A search game on a hypergraph with booby traps

Abstract A set of n boxes, located on the vertices of a hypergraph G, contain known but different rewards. A Searcher opens all the boxes in some hyperedge of G with the objective of collecting the maximum possible total reward. Some of the boxes, however, are booby trapped. If the Searcher opens a booby trapped box, the search ends and she loses all her collected rewards. We assume the number k of booby traps is known, and we model the problem as a zero-sum game between the maximizing Searcher and a minimizing Hider, where the Hider chooses k boxes to booby trap and the Searcher opens all the boxes in some hyperedge. The payoff is the total reward collected by the Searcher. This model could reflect a military operation in which a drone gathers intelligence from guarded locations, and a booby trapped box being opened corresponds to the drone being destroyed or incapacitated. It could also model a machine scheduling problem, in which rewards are obtained from successfully processing jobs but the machine may crash. We solve the game when G is a 1-uniform hypergraph (the hyperedges are all singletons), so the Searcher can open just 1 box. When G is the complete hypergraph (containing all possible hyperedges), we solve the game in a few cases: (1) same reward in each box, (2) k = 1 , and (3) n = 4 and k = 2 . The solutions to these few cases indicate that a general simple, closed form solution to the game appears unlikely.
Do the Burdens to Being Public Affect the Investment and Innovation of Newly Public Firms

We examine how regulatory burdens affect the investment and innovation of newly public firms. To do so, we exploit the Jumpstart Our Business Startups (JOBS) Act, which eliminates certain disclosur...
16 – Moisture Stress

Publisher Summary This chapter discusses moisture stress and its effect on the health of shade trees. Under natural forest conditions, trees are able to adapt to periodic changes in soil moisture. Through natural selection, wet sites are populated by moisture-loving tree species and dry sites are populated by species preferring well-drained conditions. Shade trees, however, are usually planted trees that may not be best suited for soil moisture conditions where they are planted. Soil around roadside and backyard trees rarely receives and holds as much moisture as soil in the forest. Shade trees must compete with lawns for soil moisture. Moisture stress is a common problem in shade trees. Most moisture stress falls into one of several categories—moisture deficiency, moisture excess, erosion, and physical damage from snow and ice. Trees are subject to two kinds of water deficiency stress including short-term drought during one growing season and long-term drought that accumulates moisture stress over more than one growing season.
The Deregulation of the Private Equity Markets and the Decline in IPOs

The deregulation of securities laws—in particular the National Securities Markets Improvement Act (NSMIA) of 1996—has increased the supply of private capital to late-stage private startups, which are now able to grow to a size that few private firms used to reach. NSMIA is one of a number of factors that have changed the going-public versus staying-private trade-off, helping bring about a new equilibrium where fewer startups go public, and those that do are older. This new equilibrium does not reflect an initial public offering (IPO) market failure. Rather, founders are using their increased bargaining power vis-a-vis investors to stay private longer.
3 – COMPUTATIONAL TECHNIQUES

As one's projects grow, one will gain many files. Hence, it is important to keep these files organized in a sensible way or they will soon get out of hand. A better approach is to put all the files for a given protein in a subdirectory. Appropriate subdirectories can also be made for groups of files with a common purpose, such as phasing, refinement, or fitting. The use of subdirectories in a tree structure will allow all the files to be easily backed up. Even if one starts off with several gigabytes of space, it will eventually all be filled if files are not stored off-line and deleted occasionally. To keep track of files, a naming convention should be followed. Most files are given an extension to indicate the file type. The root of the file name should be a description of the contents.
Dose–Response Models in Risk Analysis†

Various biological insults, such as exposure to hazardous chemicals, pose a risk to human health. For various purposes, including attempting to set safe limits of exposure, it is useful to quantify the risk. Direct evidence from human exposure is seldom available and most substances are assessed through bioassays on animals. The form of the dose–response relation obtained from these studies is important, as extrapolation to doses lower than those used in the experiments is necessary to try to estimate risks at the doses encountered in human exposure. Various dose–response models are presented, including multistage and multimutation carcinogenesis models. Models for continuous data are also mentioned. Models for litters are discussed as these are important in reproduction and developmental studies. Keywords: Armitage–Doll model; bioassay; carcinogenesis; dose–response; multistage model; risk
Asymmetric FDI and Tax-Treaty Bargaining: Theory and Evidence

Abstract Tax treaties are often viewed as a mechanism for eliminating tax competition, however, this approach ignores the need for bargaining over the treaty's terms. This paper focuses on how bargaining can affect the withholding taxes set under the treaty. In a simple framework, we develop hypotheses about patterns in treaty tax rates. A key determinant for these patterns is the relative size of bilateral foreign direct investment (FDI) activity. In plausible situations, more asymmetric countries will negotiate treaties with higher tax rates. This theory is then tested using 1992 data from US and Organization for Economic Cooperation and Development (OECD) bilateral tax treaties. Overall, the data supports the prediction that greater asymmetric FDI activity increases the negotiated tax rates.
Chapter 9 – GENERAL INTERPOLATION

Publisher Summary This chapter provides an overview of general interpolation. In a one-dimensional problem, it does not make a great deal of difference if one selects a local or global coordinate system for the interpolation equations, because the inter-element continuity requirements are relatively easy to satisfy. That is not true in higher dimensions. To obtain practical formulations, it is almost essential to utilize local coordinate interpolations. Doing this requires a small amount of additional work in relating the derivatives in the two coordinate systems. The chapter presents some of the procedures for deriving the interpolation functions in unit coordinates. It illustrates the Serendipity interpolation functions for quadrilateral elements that can be either, linear, quadratic, or cubic on any of its four sides. Such an element is often referred to as a transition element. The chapter also discusses hierarchical interpolation and quadrilateral elements or the quadrilateral faces of a solid element.
Dynamic Variable Selection with Spike-and-Slab Process Priors

We address the problem of dynamic variable selection in time series regression with unknown residual variances, where the set of active predictors is allowed to evolve over time. To capture time-varying variable selection uncertainty, we introduce new dynamic shrinkage priors for the time series of regression coefficients. These priors are characterized by two main ingredients: smooth parameter evolutions and intermittent zeroes for modeling predictive breaks. More formally, our proposed Dynamic Spike-and-Slab (DSS) priors are constructed as mixtures of two processes: a spike process for the irrelevant coefficients and a slab autoregressive process for the active coefficients. The mixing weights are themselves time-varying and depend on lagged values of the series. Our DSS priors are probabilistically coherent in the sense that their stationary distribution is fully known and characterized by spike-and-slab marginals. For posterior sampling over dynamic regression coefficients, model selection indicators as well as unknown dynamic residual variances, we propose a Dynamic SSVS algorithm based on forward-filtering and backward-sampling. To scale our method to large data sets, we develop a Dynamic EMVS algorithm for MAP smoothing. We demonstrate, through simulation and a topical macroeconomic dataset, that DSS priors are very effective at separating active and noisy coefficients. Our fast implementation significantly extends the reach of spike-and-slab methods to big time series data.
Alpha-Particles from Fission as Recorded by Photographic Emulsions

Eighty long range alpha-particles coincident with ${\mathrm{U}}^{235}$ fission have been observed in photographic plates. There is a tendency for the alpha-particles to emerge with greatest energy at an angle slightly greater than 90\ifmmode^\circ\else\textdegree\fi{} from the heavy fragment. In accordance with previous observers, it is found that most alpha-particles emerge approximately perpendicular. It is also found that the majority form an angle slightly obtuse to the heavy fragment. The energy of the alpha-particles is found to be derived largely from the kinetic energy of the fission fragments. The alpha-emitting fissions have approximately the same mass ratio as do normal fissions.
Economic Insecurity and the Globalization of Production

A central question in the international and comparative political economy literatures on globalization is whether economic integration increases worker insecurity in advanced economies. Previous research has focused on the role of international trade and has failed to produce convincing evidence that such a link exists. In this article, we argue that globalization increases worker insecurity, but that foreign direct investment (FDI) by multinational enterprises (MNEs) is the key aspect of integration generating risk. FDI by MNEs increases firms' elasticity of demand for labor. More-elastic labor demands, in turn, raise the volatility of wages and employment, all of which tends to make workers feel less secure. We present new empirical evidence, based on the analysis of panel data from Great Britain collected from 1991 to 1999, that FDI activity in the industries in which individuals work is positively correlated with individual perceptions of economic insecurity. This correlation holds in analyses accounting for individual-specific effects and a wide variety of control variables.
Constraint-Based Rule Mining in Large, Dense Databases

Constraint-based rule miners find all rules in a given data-set meeting user-specified constraints such as minimum support and confidence. We describe a new algorithm that directly exploits all user-specified constraints including minimum support, minimum confidence, and a new constraint that ensures every mined rule offers a predictive advantage over any of its simplifications. Our algorithm maintains efficiency even at low supports on data that is dense (e.g. relational tables). Previous approaches such as Apriori and its variants exploit only the minimum support constraint, and as a result are ineffective on dense data due to a combinatorial explosion of “frequent itemsets”.
A FLEXIBLE STATE SPACE MODEL AND ITS APPLICATIONS

The standard state space model (SSM) treats observations as imprecise measures of the Markov latent states. Our flexible SSM treats the states and observables symmetrically, which are simultaneously determined by historical observations and up to first-lagged states. The only distinction between the states and observables is that the former are latent while the latter have data. Despite the conceptual difference, the two SSMs share the same Kalman filter. However, when the flexible SSM is applied to the ARMA model, mixed frequency regression and the dynamic factor model with missing data, the state vector is not only parsimonious but also intuitive in that low-dimension states are constructed simply by stacking all the relevant but unobserved variables in the structural model.
Continuum Theory of Electrostatic Correlations at Charged Surfaces

The standard model for diffuse charge phenomena in colloid science, electrokinetics, and biology is the Poisson–Boltzmann mean-field theory, which breaks down for multivalent ions and large surface...
Finders keepers: Forfeiture laws, policing incentives, and local budgets ☆

To encourage anti-drug policing, the federal government and many state governments have enacted laws that allowpoliceagencies tokeepasubstantial fractionofthe assets thattheyseizeindrugarrests. Weuserich new data on police seizures and local spending to explore the reactions of both governments and police to the incentives created by these policies. We find that local governments offset police seizures by reducing their other allocations to police, partially undermining the incentives laid out in statute and diverting the earmarked funds to other purposes. Police, in turn, respond to the real net incentives for seizures, once local offsets are takenintoaccount,byincreasingthedrugarrestrate.Heroinpricesalsoincrease,suggestingthattheincreased emphasis on anti-drug policing raises the supply costs of illicit drugs. These findings highlight both the promise and pitfalls of using financial incentives to solve agency problems in a federal system: both local agents and intervening governments have sophisticated responses to financial incentives, and these responses must be taken into account in both designing effective policies and evaluating their consequences. © 2007 Elsevier B.V. All rights reserved.
Quantifying genetic effects on disease mediated by assayed gene expression levels

Disease variants identified by genome-wide association studies (GWAS) tend to overlap with expression quantitative trait loci (eQTLs), but it remains unclear whether this overlap is driven by gene expression levels ‘mediating’ genetic effects on disease. Here, we introduce a new method, mediated expression score regression (MESC), to estimate disease heritability mediated by the cis genetic component of gene expression levels. We applied MESC to GWAS summary statistics for 42 traits (average N = 323,000) and cis-eQTL summary statistics for 48 tissues from the Genotype-Tissue Expression (GTEx) consortium. Averaging across traits, only 11 ± 2% of heritability was mediated by assayed gene expression levels. Expression-mediated heritability was enriched in genes with evidence of selective constraint and genes with disease-appropriate annotations. Our results demonstrate that assayed bulk tissue eQTLs, although disease relevant, cannot explain the majority of disease heritability. Mediated expression score regression (MESC) is a new method that estimates disease heritability mediated by the cis genetic component of gene expression levels by using summary statistics from GWAS and eQTL studies.
Policy uncertainty and private investment in developing countries

A resurgence in private investment is a necessary ingredient of a sustainable recovery in heavily-indebted developing countries. Policy reforms in these countries involve a serious dilemma, especially when they include structural and microeconomic features. On the one hand, entrepreneurs, workers, and farmers must respond to the signals generated by the reform for the new policies to be successful. On the other hand, rational behavior by the private sector calls for withholding investment until much of the residual uncertainty regarding the eventual success of the reform is eliminated. This paper shows that even moderate amounts of policy uncertainty can act as a hefty tax on investment, and that otherwise sensible reforms may prove damaging if they induce doubts as to their permanence. A simple model is developed to link policy uncertainty to the private investment response.
Debt, Deficits and Inflation: An Application to the Public Finances of India

Abstract The paper studies the solvency of the Indian public sector and the eventual monetization and inflation that would be implied by stabilization of the debt-GNP ratio in the absence of changes in the primary deficit. The nonstationarity of the discounted public debt suggests that indefinite continuation of the pattern of behavior reflected in the historical time-series process is inconsistent with the maintenance of solvency. This message is reinforced by the recent behavior of the debt-GNP ratio and of the ratio to GNP of the sum of the primary budget surplus and seigniorage. Our estimates of the base money demand function suggests that even maximal use of the inflation tax would not be sufficient to restore solvency. Measures to reduce the primary deficit are therefore unavoidable.
Complement-induced Impairment of the Innate Immune System During Sepsis.

The complement system is an integral part of innate immunity and is chiefly responsible for controlling bacterial infections, especially those involving gramnegative organisms. To accomplish this task, serum proteins engage in a series of enzymatic cascades. The cleaved proteins assemble pores on membranous structures, which lead to cell lysis. During this process, powerful inflammatory mediators are produced, including the anaphylatoxins, C5a, C3a, and the membrane attack complex (MAC). Under systemic inflammatory conditions, an overactive complement system may compromise the effectiveness of innate immunity. We review the detrimental effects that are caused by uncontrolled complement activation during sepsis.
Predicting per-lesion local recurrence in locally advanced non-small cell lung cancer following definitive radiation therapy using pre- and mid-treatment metabolic tumor volume

We evaluated whether pre- and mid-treatment metabolic tumor volume (MTV) predicts per lesion local recurrence (LR) in patients treated with definitive radiation therapy (RT, dose≥60 Gy) for locally advanced non-small cell lung cancer (NSCLC). We retrospectively reviewed records of patients with stage III NSCLC treated from 2006 to 2018 with pre- and mid-RT PET-CT. We measured the MTV of treated lesions on the pre-RT (MTVpre) and mid-RT (MTVmid) PET-CT. LR was defined per lesion as recurrence within the planning target volume. Receiver operating characteristic (ROC) curves, cumulative incidence rates, and uni- and multivariable (MVA) competing risk regressions were used to evaluate the association between MTV and LR. We identified 111 patients with 387 lesions (112 lung tumors and 275 lymph nodes). Median age was 68 years, 69.4% were male, 46.8% had adenocarcinoma, 39.6% had squamous cell carcinoma, and 95.5% received concurrent chemotherapy. Median follow-up was 38.7 months. 3-year overall survival was 42.3%. 3-year cumulative incidence of LR was 26.8% per patient and 11.9% per lesion. Both MTVpre and MTVmid were predictive of LR by ROC (AUC = 0.71 and 0.76, respectively) and were significantly associated with LR on MVA (P = 0.004 and P = 7.1e-5, respectively). Among lesions at lower risk of LR based on MTVpre, higher MTVmid was associated with LR (P = 0.001). Per-lesion, larger MTVpre and MTVmid predicted for increased risk of LR. MTVmid was more highly predictive of LR than MTVpre and if validated may allow for further discrimination of high-risk lesions at mid-RT informing dose painting strategies.
Some fractal thoughts about the COVID-19 infection outbreak

Abstract Some ideas are presented about a geometric motivation of the apparent capacity of generalized logistic equations to describe the outbreak of quite many epidemics, possibly including that of the COVID-19 infection. This interpretation pivots on the complex, possibly fractal, structure of the locus describing the “contagion event set”, and on what can be learnt from the models of trophic webs with “herd behaviour”. Under the hypothesis that the total number of cases, as a function of time, is fitted by a solution of the Generalized Richards Model, it is argued that the exponents appearing in that differential equation, usually determined empirically, represent the geometric signature of the non-space filling, network-like locus on which contagious contacts take place.
The Evolution of Human Cancer Gene Duplications across Mammals.

Cancer is caused by genetic alterations that affect cellular fitness, and multicellular organisms have evolved mechanisms to suppress cancer such as cell cycle checkpoints and apoptosis. These pathways may be enhanced by the addition of tumor suppressor gene paralogs or deletion of oncogenes. To provide insights to the evolution of cancer suppression across the mammalian radiation, we estimated copy numbers for 548 human tumor suppressor gene and oncogene homologs in 63 mammalian genome assemblies. The naked mole rat contained the most cancer gene copies, consistent with the extremely low rates of cancer found in this species. We found a positive correlation between a species' cancer gene copy number and its longevity, but not body size, contrary to predictions from Peto's Paradox. Extremely long-lived mammals also contained more copies of caretaker genes in their genomes, suggesting that the maintenance of genome integrity is an essential form of cancer prevention in long-lived species. We found the strongest association between longevity and copy numbers of genes that are both germline and somatic tumor suppressor genes, suggesting that selection has acted to suppress both hereditary and sporadic cancers. We also found a strong relationship between the number of tumor suppressor genes and the number of oncogenes in mammalian genomes, suggesting that complex regulatory networks mediate the balance between cell proliferation and checks on tumor progression. This study is the first to investigate cancer gene expansions across the mammalian radiation and provides a springboard for potential human therapies based on evolutionary medicine.
Rank and bias in families of hyperelliptic curves via Nagao's conjecture

Abstract Let X : y 2 = f ( x ) be a hyperelliptic curve over Q ( T ) of genus g ≥ 1 . Assume that the jacobian of X over Q ( T ) has no subvariety defined over Q . Denote by X t the specialization of X to an integer T = t , let a X t ( p ) be its trace of Frobenius, and let A X , r ( p ) = 1 p ∑ t = 1 p a X t ( p ) r be its r-th moment. The first moment is related to the rank of the jacobian J X ( Q ( T ) ) by a generalization of a conjecture of Nagao: lim X → ∞ ⁡ 1 X ∑ p ≤ X − A X , 1 ( p ) log ⁡ p = rank J X ( Q ( T ) ) . Generalizing a result of S. Arms, A. Lozano-Robledo, and S.J. Miller, we compute first moments for various families resulting in infinitely many hyperelliptic curves over Q ( T ) having jacobian of moderately large rank 4 g + 2 , where g is the genus; by Silverman's specialization theorem, this yields hyperelliptic curves over Q with large rank jacobian. Note that Shioda has the better record in this direction: he constructed hyperelliptic curves of genus g with jacobian of rank 4 g + 7 . In the case when X is an elliptic curve, Michel proved p ⋅ A X , 2 = p 2 + O ( p 3 / 2 ) . For the families studied, we observe the same second moment expansion. Furthermore, we observe the largest lower order term that does not average to zero is on average negative, a bias first noted by S.J. Miller in the elliptic curve case. We prove this bias for a number of families of hyperelliptic curves.
Pathogen reduction of SARS-CoV-2 virus in plasma and whole blood using riboflavin and UV light.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has recently been identified as the causative agent for Coronavirus Disease 2019 (COVID-19). The ability of this agent to be transmitted by blood transfusion has not been documented, although viral RNA has been detected in serum. Exposure to treatment with riboflavin and ultraviolet light (R + UV) reduces blood-borne pathogens while maintaining blood product quality. Here, we report on the efficacy of R + UV in reducing SARS-CoV-2 infectivity when tested in human plasma and whole blood products. STUDY DESIGN AND METHODS: SARS-CoV-2 (isolate USA-WA1/2020) was used to inoculate plasma and whole blood units that then underwent treatment with riboflavin and UV light (Mirasol Pathogen Reduction Technology System, Terumo BCT, Lakewood, CO). The infectious titers of SARS-CoV-2 in the samples before and after R + UV treatment were determined by plaque assay on Vero E6 cells. Each plasma pool (n = 9) underwent R + UV treatment performed in triplicate using individual units of plasma and then repeated using individual whole blood donations (n = 3). RESULTS: Riboflavin and UV light reduced the infectious titer of SARS-CoV-2 below the limit of detection for plasma products at 60-100% of the recommended energy dose. At the UV light dose recommended by the manufacturer, the mean log reductions in the viral titers were &#8805; 4.79 � 0.15 Logs in plasma and 3.30 � 0.26 in whole blood units. CONCLUSION: Riboflavin and UV light effectively reduced the titer of SARS-CoV-2 to the limit of detection in human plasma and by 3.30 � 0.26 on average in whole blood. Two clades of SARS-CoV-2 have been described and questions remain about whether exposure to one strain confers strong immunity to the other. Pathogen-reduced blood products may be a safer option for critically ill patients with COVID-19, particularly those in high-risk categories.
Breakdown of electroneutrality in nanopores

Abstract Ion transport in extremely narrow nanochannels has gained increasing interest in recent years due to unique physical properties at the nanoscale and the technological advances that allow us to study them. It is tempting to approach this confined regime with the theoretical tools and knowledge developed for membranes and microfluidic devices, and naively apply continuum models, such as the Poisson-Nernst-Planck and Navier-Stokes equations. However, it turns out that some of the most basic principles we take for granted in larger systems, such as the complete screening of surface charge by counter-ions, can break down under extreme confinement. We show that in a truly one-dimensional system of ions interacting with three-dimensional electrostatic interactions, the screening length is exponentially large, and can easily exceed the macroscopic length of a nanotube. Without screening, electroneutrality breaks down within the nanotube, with fundamental consequences for ion transport and electrokinetic phenomena. In this work, we build a general theoretical framework for electroneutrality breakdown in nanopores, focusing on the most interesting case of a one-dimensional nanotube, and show how it provides an elegant interpretation for the peculiar scaling observed in experimental measurements of ionic conductance in carbon nanotubes.
The Distributional Impact of Recessions: the Global Financial Crisis and the Pandemic Recession

Using the U.S. Current Population Survey data, this paper compares the distributional impacts of the Pandemic Crisis and those of the Global Financial Crisis in terms of (i) worker characteristics, (ii) job characteristics–“social” (where individuals interact to consume goods), “teleworkable” (where individuals have the option of working at home), and “essential” jobs (which were not subject to government mandated shut-downs during the recent recession), and (iii) wage distributions. We find that young and less educated workers have always been affected more in recessions, while women and Hispanics were more severely affected during the Pandemic Recession. Surprisingly, teleworkable, social and essential jobs have been historically less cyclical. This historical acyclicality of teleworkable occupations is attributable to its higher share of skilled workers. Unlike during the Global Financial Crisis, however, employment in social industries fell more whereas employment in teleworkable and essential jobs fell less during the Pandemic Crisis. Lastly, during both recessions, workers at low-income earnings have suffered more than top-income earners, suggesting a significant distributional impact of the two recessions.
The ability of dual whitening anti-caries mouthrinses to remove extrinsic staining and enhance caries lesion remineralization - An in vitro study.

OBJECTIVES This laboratory study investigated the ability of dual whitening anti-caries mouthrinses to remove extrinsic staining from artificially stained caries lesions and to enhance their remineralization and fluoridation. MATERIALS AND METHODS Early caries lesions were created in bovine enamel specimens. The lesions were artificially stained and pH cycled for 10 days with the daily cycling regimen consisting of twice daily 60s-treatments with one of 11 mouthrinses, a 4-h demineralization period and artificial saliva treatments in between. Mouthrinses were eight commercially available products, all containing 100ppm fluoride but utilizing hydrogen peroxide, pyro-, tri- or hexametaphosphate salts and/or sodium bicarbonate. The three control mouthrinses were 100ppm fluoride, 30 % hydrogen peroxide and deionized water. Enamel color changes (ΔE) were determined spectrophotometrically. Vickers surface microhardness (VHN) was used to determine lesion remineralization. Enamel fluoride content (EFC) was determined using the microbiopsy technique. Data were analyzed using ANOVA. RESULTS ΔE was significantly different among groups (p=0.0045). Thirty percent hydrogen peroxide was superior to all other mouthrinses, while there were no differences between commercial mouthrinses and deionized water. There were small, directional but non-significant differences between commercial mouthrinses with those containing hydrogen peroxide providing better whitening. There were no significant differences between mouthrinses in their ability to remineralize caries lesions (p=0.2898). EFC differed among groups (p<0.0001), with the two mouthrinses containing pyrophosphate salts having lower EFC than all but the deionized water group. CONCLUSIONS Artificially stained caries lesions show reduced susceptibility to fluoride remineralization and whitening effects of commercial whitening and anti-caries mouthrinses. CLINICAL RELEVANCE Artificially stained caries lesions appear to require stronger than over-the-counter interventions to successfully whiten and remineralizing them.
A clinically and genomically annotated nerve sheath tumor biospecimen repository

Nerve sheath tumors occur as a heterogeneous group of neoplasms in patients with neurofibromatosis type 1 (NF1). The malignant form represents the most common cause of death in people with NF1, and even when benign, these tumors can result in significant disfigurement, neurologic dysfunction, and a range of profound symptoms. Lack of human tissue across the peripheral nerve tumors common in NF1 has been a major limitation in the development of new therapies. To address this unmet need, we have created an annotated collection of patient tumor samples, patient-derived cell lines, and patient-derived xenografts, and carried out high-throughput genomic and transcriptomic characterization to serve as a resource for further biologic and preclinical therapeutic studies. In this work, we release genomic and transcriptomic datasets comprised of 55 tumor samples derived from 23 individuals, complete with clinical annotation. All data are publicly available through the NF Data Portal and at http://synapse.org/jhubiobank.
Gromov-Wasserstein Averaging in a Riemannian Framework

We introduce a theoretical framework for performing statistical tasks-including, but not limited to, averaging and principal component analysis-on the space of (possibly asymmetric) matrices with arbitrary entries and sizes. This is carried out under the lens of the Gromov-Wasserstein (GW) distance, and our methods translate the Riemannian framework of GW distances developed by Sturm into practical, implementable tools for network data analysis. Our methods are illustrated on datasets of letter graphs, asymmetric stochastic blockmodel networks, and planar shapes viewed as metric spaces. On the theoretical front, we supplement the work of Sturm by producing additional results on the tangent structure of this "space of spaces", as well as on the gradient flow of the Frechet functional on this space.
Fair Correlation Clustering

In this paper, we study correlation clustering under fairness constraints. Fair variants of $k$-median and $k$-center clustering have been studied recently, and approximation algorithms using a notion called fairlet decomposition have been proposed. We obtain approximation algorithms for fair correlation clustering under several important types of fairness constraints. Our results hinge on obtaining a fairlet decomposition for correlation clustering by introducing a novel combinatorial optimization problem. We define a fairlet decomposition with cost similar to the $k$-median cost and this allows us to obtain approximation algorithms for a wide range of fairness constraints. We complement our theoretical results with an in-depth analysis of our algorithms on real graphs where we show that fair solutions to correlation clustering can be obtained with limited increase in cost compared to the state-of-the-art (unfair) algorithms.
Analysis of a spatially inhomogeneous stochastic partial differential equation epidemic model

This work proposes and analyzes a family of spatially inhomogeneous epidemic models. This is our first effort to use stochastic partial differential equations (SPDEs) to model epidemic dynamics with spatial variations and environmental noise. After setting up the problem, the existence and uniqueness of solutions of the underlying SPDEs are examined. Then, definitions of permanence and extinction are given, and certain sufficient conditions are provided for permanence and extinction. Our hope is that this paper will open up windows for investigation of epidemic models from a new angle.
Degrees of iterates of rational maps on normal projective varieties

Let X be a normal projective variety defined over an algebraically closed field of arbitrary characteristic. We study the sequence of intermediate degrees of the iterates of a dominant rational selfmap of X, recovering former results by Dinh, Sibony [DS05b], and by Truong [Tru16].Precisely, we give a new proof of the submultiplicativity properties of these degrees and of its birational invariance. Our approach exploits intensively positivity properties in the space of numerical cycles of arbitrary codimension. In particular, we prove an algebraic version of an inequality first obtained by Xiao [Xia15] and Popovici [Pop16], which generalizes Siu's inequality (see [Trap95]) to algebraic cycles of arbitrary codimension. This allows us to show that the degree of a map is controlled up to a uniform constant by the norm of its action by pull-back on the space of numerical classes in X.
Direct Synthesis of Iterative Algorithms With Bounds on Achievable Worst-Case Convergence Rate.

Iterative first-order methods such as gradient descent and its variants are widely used for solving optimization and machine learning problems. There has been recent interest in analytic or numerically efficient methods for computing worst-case performance bounds for such algorithms, for example over the class of strongly convex loss functions. A popular approach is to assume the algorithm has a fixed size (fixed dimension, or memory) and that its structure is parameterized by one or two hyperparameters, for example a learning rate and a momentum parameter. Then, a Lyapunov function is sought to certify robust stability and subsequent optimization can be performed to find optimal hyperparameter tunings. In the present work, we instead fix the constraints that characterize the loss function and apply techniques from robust control synthesis to directly search over algorithms. This approach yields stronger results than those previously available, since the bounds produced hold over algorithms with an arbitrary, but finite, amount of memory rather than just holding for algorithms with a prescribed structure.
Handover-Count based Velocity Estimation of Cellular-Connected UAVs

Cellular-connected unmanned aerial vehicles (UAVs) are expected to play a major role in various civilian and commercial applications in the future. While existing cellular networks can provide wireless coverage to UAV user equipment (UE), such legacy networks are optimized for ground users which makes it challenging to provide reliable connectivity to aerial UEs. To ensure reliable and effective mobility management for aerial UEs, estimating the velocity of cellular-connected UAVs carries critical importance. In this paper, we introduce an approximate probability mass function (PMF) of handover count (HOC) for different UAV velocities and different ground base station (GBS) densities. Afterward, we derive the Cramer-Rao lower bound (CRLB) for the velocity estimate of a UAV, and also provide a simple unbiased estimator for the UAV's velocity which depends on the GBS density and HOC measurement time. Our simulation results show that the accuracy of velocity estimation increases with the GBS density and HOC measurement window. Moreover, the velocity of commercially available UAVs can be estimated efficiently with reasonable accuracy.
Balance Transfers and Bailouts in Credit Networks using Blockchains

In this paper, we propose a technique for rebalancing link weights in decentralized credit networks. Credit networks are peer-to-peer trust-based networks that enable fast and inexpensive cross-currency transactions compared to traditional bank wire transfers. Although researchers have studied security of transactions and privacy of users of such networks, and have invested significant efforts into designing efficient routing algorithms for credit networks, comparatively little work has been done in the area of replenishing credit links of users in the network. This is achieved by a process called rebalancing that enables a poorly funded user to create incoming as well as outgoing credit links. We propose a system where a user with zero or no link weights can create incoming links with existing, trusted users in the network, in a procedure we call balance transfer, followed by creating outgoing links to existing or new users that would like to join the network, a process we call bailout. Both these processes together constitute our proposed rebalancing mechanism.
Close evaluation of layer potentials in three dimensions

Abstract We present a simple and effective method for evaluating double- and single-layer potentials for Laplace's equation in three dimensions close to the boundary. The close evaluation of these layer potentials is challenging because they are nearly singular integrals. The method we propose is based on writing these layer potentials in spherical coordinates where the point at which their kernels are peaked maps to the north pole. An N-point Gauss-Legendre quadrature rule is used for integration with respect to the polar angle rather than the cosine of the polar angle. A 2N-point periodic trapezoid rule is used to compute the integral with respect to the azimuthal angle which acts as a natural and effective averaging operation in this coordinate system. The numerical method resulting from combining these two quadrature rules in this rotated coordinate system yields results that are consistent with asymptotic behaviors of the double- and single-layer potentials at close evaluation distances. In particular, we show that the error in computing the double-layer potential, after applying a subtraction method, is quadratic with respect to the evaluation distance from the boundary, and the error is linear for the single-layer potential. We improve upon the single-layer potential by introducing an alternate approximation based on a perturbation expansion and obtain an error that is quadratic with respect to the evaluation distance from the boundary.
Product sequencing and pricing under cascade browse model

Abstract We study the assortment optimization problem under the newly proposed cascade browse model. We propose a constant approximate solution to this problem. As a byproduct, we propose the first fully polynomial-time approximation scheme (FPTAS) for the classic assortment optimization problem subject to one capacity constraint and one cardinality constraint. We also studied a joint pricing and sequencing problem under the above model and develop a constant approximate solution to this problem.
Risk and Trouble: Adam Smith on Profit and the Protagonists of Capitalism

To better account for deepening global inequalities, political theory could greatly enhance empirical and normative work by answering a fundamental question: What is profit? When engaging political‐economic questions, however, theorists often begin thinking from the concept of private property. This, I argue, has obscured the central role of profit as an organizing category for capitalist societies since the eighteenth century. Grounded in the dynamic and uncertain processes of production and accumulation, profit displaces the proprietary citizen and subject of natural rights and gives rise to new social protagonists, who lay claim to increasingly asymmetric rewards. In particular, the article calls attention to a dangerous contemporary sensibility, which sees profit as inherently unlimited. As a viable, robust alternative, it presents Adam Smith's idea of profit as a regular, uniform rate that acts as a productive constraint on business activity, shapes character, and safeguards against risk by widely distributing its costs.