cssi/SciSciGPT-SciSciNet huggingface dataset:
Accessing the Internet through the Neighbor's Wireless Internet Connection: Physical Trespass in Virtual Reality

As wireless computer networks are becoming commonplace, so also is the practice of accessing the Internet through another's wireless network. The practice raises a simple question of law: Does accessing a wireless network, without express authorization, violate the property rights of the network operator? This Article argues that it does. A neighbor who intentionally accesses the Internet through a network operator's connection appears to trespass on physical property of the operator - the operator's router. Recent Internet jurisprudence suggests that the electronic signals that the neighbor sends through the router are sufficient to find trespassory physical contact. The same jurisprudence suggests that the possibility that the neighbor could slow down the operator's Internet connection satisfies the tort's requirement of harm. Furthermore, the defense of consent does not appear to apply. Although the neighbor can raise an argument that the network operator consents to the neighbor's access when the operator fails to password protect the network, this argument is flawed. Failure to protect property does not imply consent to use property. The absence of password protection does not demonstrate consent, especially given that there is no economic reason that a network operator would want a neighbor to free ride on the operator's Internet connection. Finally, from a policy standpoint, the neighbor's conduct should be proscribed because of its negative externalities to Internet service providers. The free-riding neighbor strips Internet service providers of a return on their investment in Internet technology. To prevent this outcome, the conduct should be tortious. Trespass to chattel should lie.
CEO Equity Incentives and Audit Fees

This study examines whether CEO equity incentives have an impact on audit pricing. Prior studies investigate whether CEO equity incentives motivate executives to manage earnings for personal financial gains. Our focus is on whether auditors perceive CEO equity incentives to be associated with greater earnings manipulation risk and incorporate such risk in their pricing decisions. We find that CEO equity portfolio vega is positively related to audit fees after controlling for other determinants of audit fees, while equity portfolio delta is not significantly related to audit fees. This result holds after we account for potential endogeneity. The evidence suggests that auditors are concerned about CEOs’ incentives to manage earnings because equity holdings tie CEOs’ wealth to risk and cause CEOs to be less risk-averse. The findings in our study improve our understanding of how executive compensation affects auditors’ pricing decisions.
Humans, Computers, and Binding Commitment

Contracts in electronic commerce do not look like the traditional contract theory picture of a meeting of the minds or autonomous consent. Increasingly, deals are being made between a human and a computer, or between two computers managed only remotely by humans. This paper addresses the implications of that trend on our understanding of contractual commitment, and on the law that determines which commitments are binding. Specifically, the paper addresses (a) "click wrap" contracts, which purport to be formed by on-screen acts such as clicking on a button labeled "I agree," or even by the mere act of visiting a web site; (b) "machine-made" contracts, which are formed directly by software programs acting as "agents" for humans or for firms; and (c) "viral contracts," in which restrictions on use are built directly into a software product or other digitized information content, thereby purporting to bind all subsequent users (as well as the initial purchaser). Each of these has analogies in pre-electronic law -- for example, in contracts of adhesion; in the actions of shipping clerks in the so-called "battle of the forms;" and in covenants running with real property. But each of these pre-electronic practices is usually viewed as an exception to our "normal" picture of contract formation. The current trends in electronic contracting threaten to make those exceptions the rule. This paper distinguishes between autonomy-based theories of contract, in which all of the above practices are highly problematic, from efficiency-based theories, in which many of these practices are not (necessarily) problematic at all. It also draws an analogy to Calabresi and Melamed's distinction between property rules and liability rules: the contract-formation issue is, in many respects, a question about what one party may or must do in order to alter the legal rights of another. Finally, the paper also describes and critiques some proposed legislative solutions, including the Uniform Computer Information Transactions Act (UCITA) and the Uniform Electronic Transactions Act (UETA).
The Story of Justice: Retribution, Mercy, and the Role of Emotions in the Capital Sentencing Process

This essay examines Martha Nussbaum's prescription fortempering retribution with mercy in the capitalsentencing process. Nussbaum observes that theoperation of retribution in the ancient world resultedin harsh and indiscriminate punishment without regardto the particularities of the offender and his crime. In the interest of mercy, Nussbaum advocates the useof the novel as a model for a more compassionatesentencing process. An examination of Nussbaum's``novel prescription'' reveals that the retribution thatoperates in the modern criminal law, and in theSupreme Court's capital sentencing jurisprudence,already accommodates the values of justice –individuation, particularization, and proportionality– that are characteristic of the mercy tradition. Moreover, the rich narrative approach that Nussbaumfavors is by no means congenial to mercifulpunishment. Because the particularistic detail of thenovel form is not confined to the sympatheticportrayal of the defendant, the emotionalism thatNussbaum urges encompasses as well emotional detailsabout the characteristics of the defendant's victim. Such victim impact evidence is consistent with thenovel form, but is unlikely to promote mercifuljudgment. Instead, the details of victim impactevidence can be expected to exacerbate a sentencingauthority's inclination to judge a capital defendantharshly. The novel thus provides a poor model for thecapital sentencing process because it fosters the sortof unchecked emotionalism that undermines the rationaldecision making that the Supreme Court has sought toachieve.
The Persistence of Ecological-Economic Systems: Alternate Measures and their Properties

A number of ecologists and some economists have commented on the significance of persistence as a stability concept for jointly determined ecological-economic systems. This notwithstanding, the economics and the regional science literatures have paid scant attention to the problem of computing an ecological-economic system's persistence. As such, this paper has two objectives. First, we derive three measures of the persistence of a jointly determined ecological-economic system whose temporal behavior is governed by the presence of thresholds. Next, we compare and contrast these three measures. Finally, we discuss their theoretical properties and their practical uses.
Cyclical unemployment and infant health.

Abstract This study provides evidence on the effect of cyclical unemployment on infant health. We match individual-level data from a detailed survey of mothers and their children in Memphis, TN, with 5-year average census-tract unemployment rates from the American Community Survey. Our findings indicate that a one percentage point increase in the local unemployment rate is associated with a statistically significant increase in the probability of having a low birthweight baby (a baby weighing less than 2500 grams). We also find evidence of a statistically significant decrease in gestational age. These effects are concentrated among infants born to mothers without a college education and into households earning less than $25,000 a year.
The rule of three: How the third event signals the emergence of a streak.

It is well established that people perceive streaks where they do not exist. However, little is known about what constitutes a streak in the mind of an observer. This paper proposes that the third repeat event in a sequence is pivotal to the subjective belief that a streak is occurring. In five studies, we find direct and indirect evidence that perceived streakiness plateaus with the third repeat outcome in a sequence. The evidence to support this rule of three comes from various domains, including: observation of randomly determined probabilistic outcomes, investment decisions in response to performance histories, and basketball shooting percentages.
Delegation and Positive-Sum Bureaucracies

I develop a formal model to investigate why Congress would choose to delegate authority to an agency whose actions can be controlled, ex post, by a President with divergent policy preferences. Because the President and the Congress might find different policies to be salient to their constituencies, I demonstrate that executive review of agency rulemaking can benefit both branches of government, relative to legislative delegation without the possibility of such review. In trying to undermine the impacts of executive oversight, agencies propose policies that could benefit Congress if the President chose not to intervene in agency policymaking. If the President does intervene, it will establish policy outcomes that can be more desirable than what would ensue absent such review. This joint-desirability of executive review is more likely when congressional and presidential policy preferences are relatively aligned and when congressional and agency policy preferences are relatively divergent. Executive review ...
Implications of power: When the CEO can pressure the CFO to bias reports

Abstract Building on archival, anecdotal, and survey evidence on managers׳ roles in accounting manipulations, I develop an agency model to examine the effects of a CEO׳s power to pressure a CFO to bias a performance measure, like earnings. This power has implications for incentive compensation, reporting quality, firm value, and information rents. Predictions from the model provide potential explanations for the differing results from recent empirical studies on the impact of regulatory interventions like SOX and the extent to which the CEO׳s or CFO׳s incentives significantly impact on earnings management. The model also identifies conditions under which either a powerful or a non-powerful CEO can extract rents, which can help explain mixed empirical results on the association between CEO power and “excessive” compensation.
Adverse selection and reputation in a world of cheap talk

Abstract Internet message boards are inherently a world of cheap talk due to the anonymity of message authors. This paper investigates whether a pecuniary reputation system influences the adverse selection problem endemic to message boards. First, we find evidence that authors with high reputation scores are less likely to voluntarily offer a buy–hold–sell sentiment in a particular message. Second, we find that authors with no reputation at stake tend to be more bearish with their sentiment but, after controlling for selection, authors with more reputation at stake tend to be bullish in their sentiment. Third, we find that high-reputation authors tend to offer more accurate sentiments on the day their message was posted, which suggests day-trading behavior by authors, but that higher-reputation authors are no more accurate than others after the day of posting. Our results suggest that reputation, coupled with a small pecuniary reward system, can materially influence the adverse selection problem in a world of cheap talk.
Legal Regulation of Health-Related Behavior: A Half Century of Public Health Law Research

Legal intervention to influence individual health behavior has increased dramatically since the 1960s. This article describes the rise of law as a tool of public health and the scientific research that has assessed and often guided it, with a focus on five major domains: traffic safety, gun violence, tobacco use, reproductive health, and obesity. These topical stories illustrate both law's effectiveness and its limitations as a public health tool. They also establish its popularity by the most apt of metrics—the willingness of legislators to enact it. The five examples demonstrate that public health law research can and does influence the development and refinement of legal interventions over time. Measuring the impact of laws can be difficult, but the field has the tools of theory and methods necessary to produce robust results. It is past time for public health research to receive institutional, professional, and funding support commensurate with its social importance.
Nonparametric Estimation of Average Treatment Effects under Exogeneity: A Review

Recently there has been a surge in econometric work focusing on estimating average treatment effects under various sets of assumptions. One strand of this literature has developed methods for estimating average treatment effects for a binary treatment under assumptions variously described as exogeneity, unconfoundedness, or selection on observables. The implication of these assumptions is that systematic (for example, average or distributional) differences in outcomes between treated and control units with the same values for the covariates are attributable to the treatment. Recent analysis has considered estimation and inference for average treatment effects under weaker assumptions than typical of the earlier literature by avoiding distributional and functional-form assump- tions. Various methods of semiparametric estimation have been proposed, including estimating the unknown regression functions, matching, meth- ods using the propensity score such as weighting and blocking, and combinations of these approaches. In this paper I review the state of this literature and discuss some of its unanswered questions, focusing in particular on the practical implementation of these methods, the plausi- bility of this exogeneity assumption in economic applications, the relative performance of the various semiparametric estimators when the key assumptions (unconfoundedness and overlap) are satise ed, alternative estimands such as quantile treatment effects, and alternate methods such as Bayesian inference.
“I Might Need a Good Lawyer, Could Be Your Funeral, My Trial”: Global Clinical Legal Education and the Right to Counsel in Civil Commitment Cases

The quality of counsel assigned to represent individuals facing involuntary civil commitment to psychiatric hospitals is, in most American jurisdictions, mediocre or worse. In many other nations, it is non-existent, or so minimal as to offer only the illusion of legal safeguards. (Perhaps) remarkably, there has been virtually no mention of this latter scandal in the legal literature. Also, there has been little attention paid to this development by the clinical education movement (domestically and globally). A variety of interrelated factors, however, may shed some light on this scandal, and may, encouragingly, lead to social change in the future: - emerging caselaw construing the European Convention on this issue - the publication of the United Nations Convention on the Rights of Persons with Disabilities which will eventually focus international attention on this issue - the first burst of professional interest in this issue, as evidenced by programs, workshops and panels at the Congress of the International Academy of Law and Mental Health, and other interdisciplinary groups that focus on questions of psychology, psychiatry and law - the focus by mental disability law-specific NGOs (e.g., Mental Disability Rights International; Mental Disability Advocacy Center) on institutional conditions in Central and Eastern Europe and in Central and South America, calling attention to this issue, and - the emergence of the Global Alliance for Justice Education as a factor in the promotion of socially relevant legal education, similarly calling attention to these issues. This paper will proceed in this manner. In Part I, I will review developments in the United States, with special focus on the Montana case of In the Matter of the Mental Health of K.G.F., without doubt the most comprehensive decision on the scope of and meaning of the right to counsel in this context from any jurisdiction in the world. In Part II, I will survey an array of other jurisdictions (common law, civil law, and mixed), and consider the range of findings (from nations in which there is no counsel, to perfunctory-at-best-counsel, to almost-adequate counsel). In Part III, I will consider other major legal, political and social developments that may, it is hoped, shine some light on these issues. In Part IV, I will examine these issues from the perspective of clinical legal education. In Part V, I will consider the impact of sanism and pretextuality on these developments. Finally, I will offer some modest conclusions. Sanism is an irrational prejudice of the same quality and character of other irrational prejudices that cause (and are reflected in) prevailing social attitudes of racism, sexism, homophobia, and ethnic bigotry. See infra Part V. Pretextuality defines the ways in which courts accept (either implicitly or explicitly) testimonial dishonesty and engage similarly in dishonest (and frequently meretricious) decisionmaking. See infra Part V.
On the Indeterminacy Crisis: Critiquing Critical Dogma

I am not thinking of these dogmas as determining men's opinions but rather as completely controlling the expression of all opinions. People will live under an absolute, palpable tyranny, though without being able to say they are not free. . . . For dogma is expressed in the form of an assertion, and is unshakable, but at the same time any practical opinion can be made to harmonize with it; admittedly more easily in some cases than in others. It is not a wall setting limits to what can be believed, but more like a brake which, however, practically serves the same purpose; it's almost as though someone were to attach a weight to your foot to restrict your freedom of movement. This is how dogma becomes irrefutable and beyond the reach of attack.
Do Property Rights Promote Investment But Cause Deforestation? Quasi-Experimental Evidence from Nicaragua

Abstract Many policymakers argue that property rights decrease deforestation. Some theoretical papers also make this prediction, arguing that property rights decrease discount rates applied to a long-term investment in forestry. However, the effect is theoretically ambiguous. The paper takes a novel instrumental variables approach based on Nicaragua's agrarian reform to test for the effect, using a new dataset—Nicaragua's 2001 agricultural census. It finds that property rights significantly increase deforestation. The model, supported by the data, suggests a likely mechanism for this relationship: property rights increase investment, increasing agricultural productivity and therefore the returns to deforestation.
Martin Luther King Jr.'s Lessons for Lawyers in a Time of Market Disruption

This essay, delivered as the 2014 Tabor Lecture at Valparaiso University Law School, argues that our conception of the lawyer’s work lacks a rich and full understanding of the human person. This absence may not only hurt the lawyer’s ability to derive meaning from her work and advance the common good, but also may contribute to a perception that lawyers are becoming expendable in a market of fungible business service providers. The failure is starkly apparent when one considers the anthropological commitments that permeated the work and worldview of Martin Luther King Jr. Though he was not a lawyer, he was an advocate for the interests of others, and he was a Christian who was able to live out his beliefs in ways that were accessible and influential to those who did not share the underlying religious premises. While King’s moral duties were not constrained by the more particular fiduciary duty that lawyers owe to their clients, I believe that lawyers overstate the degree to which their moral agency is so constrained, and in doing so, abdicate moral responsibility for their work. Lawyers who endeavor to practice with the person at the center, as King did, will act as: (1) subjects; (2) healers; (3) prophets; and (4) realists.
Earnings management and accounting income aggregation

Quarterly earnings allow aggregation into annual earnings in four different ways. Fiscal year earnings is one measure of annual earnings, the others being earnings for annual periods ending at interim quarter-ends. We investigate earnings management in fiscal year earnings relative to these alternative measures of firms’ annual earnings. We confirm prior findings in Burgstahler and Dichev (1997. Earnings management to avoid earnings decreases and losses. Journal of Accounting and Economics 24, 99–126) of discontinuities around zero and prior year earnings in histograms of earnings. Subsequent research questions whether these discontinuities are evidence of earnings management. Using histograms of our alternative annual earnings measures, we offer evidence suggesting earnings management is responsible for the discontinuities.
An Empirical Investigation on Social Media Users' Demand for Financial Information Distributed via Social Media Platforms

Managers feel significant pressure to establish a social media presence that differentiates their organization from rivals, though few managers feel confident that their organization provides social media users with the information they desire. Thus, while the supply of information provided to social media users by organizations continues to proliferate rapidly, few studies have investigated the information social media users want organizations to provide. This study explores the information desires of two social media user groups: nonprofessional investors and non-investors. We create and validate a social media information content taxonomy using data from three experiments, finding the information desires of both groups are relatively similar. Specifically, social media users primarily want organizations to provide them with information that addresses them as customers, though we find evidence that nonprofessional investors desire financial information more than non-investors. We also find some evidence...
Pensioners, Bondholders, and Unfair Discrimination in Municipal Bankruptcy

Detroit recently confirmed its plan of debt adjustment under which the city has endeavored to adjust its pension obligations. The court’s confirmation order and oral opinion on the record present what is perhaps the most significant decision regarding a key question facing any city attempting to adjust pensions in bankruptcy: can a city propose to pay its pension claimants significantly more than its other unsecured creditors? This question involves interpreting the Bankruptcy Code’s unfair discrimination rule.The Detroit bankruptcy court applied a novel interpretation of unfair discrimination, eschewing the relatively thin body of case law interpreting this rule, and suggesting that the rule should have a municipal bankruptcy-specific meaning.This article contends that there is no need for such a specialized interpretation of unfair discrimination. Many of the factors that motivated the court’s departure from the case law can actually be addressed more effectively under the case law developed for corporate reorganization. Adhering to the corporate reorganization statute has statutory and historical support. Further, such a rule would provide a more workable structure for determining when discrimination is unfair.
An empirical behavioral model of liquidity and volatility

Abstract We develop a behavioral model for liquidity and volatility based on empirical regularities in trading order flow in the London Stock Exchange. This can be viewed as a very simple agent-based model in which all components of the model are validated against real data. Our empirical studies of order flow uncover several interesting regularities in the way trading orders are placed and cancelled. The resulting simple model of order flow is used to simulate price formation under a continuous double auction, and the statistical properties of the resulting simulated sequence of prices are compared to those of real data. The model is constructed using one stock (AZN) and tested on 24 other stocks. For low volatility, small tick size stocks (called Group I) the predictions are very good, but for stocks outside Group I they are not good. For Group I, the model predicts the correct magnitude and functional form of the distribution of the volatility and the bid-ask spread, without adjusting any parameters based on prices. This suggests that at least for Group I stocks, the volatility and heavy tails of prices are related to market microstructure effects, and supports the hypothesis that, at least on short time scales, the large fluctuations of absolute returns | r | are well described by a power law of the form P ( | r | > R ) ∼ R - α r , with a value of α r that varies from stock to stock.
Presidents, Preemption, and the States

Early in his administration, President Obama issued a memorandum about preemption that ordered federal agencies to fully consider state interests before preempting state laws. The Obama memorandum was a rebuke to the Bush Administration, which had regularly inserted preemption provisions into federal regulations in areas affecting health, consumer safety, and the environment. As a result of preemption, state laws could not be more protective than federal standards, and corporations were spared state tort lawsuits and state regulatory regimes. Preemption not only tends to pit corporate interests against the public welfare, but it can also undermine federalism. There is currently a lively debate as to whether the best institutional actor to foster federalism is the judiciary, Congress, or agencies. Yet despite the centrality of modern Presidents to preemption policy, the role of the President is all but ignored in preemption scholarship. Accordingly, this Article adds the President to the mix. In general, congressional lawmaking about preemption is preferable to presidential preemption because states have more opportunities to influence Congress. Nevertheless, there are many situations in which Congress cannot or will not consider the preemption implications of legislation. Accordingly, this Article explores ways in which the President can effectively ensure a vibrant role for the states in federalism regimes by using his Article II powers to push federal agencies to do a better job of considering state interests when they regulate.
Testing heterogeneous-agent models: an alternative aggregation approach

Abstract Starting from the cross-sectional aggregation of marginal utilities, rather than intertemporal marginal rates of substitution, this paper develops a new heterogeneous-agent pricing kernel. A closed-form version of the new kernel depends on changes in the cross-sectional variance of log consumption, rather than the variance of changes in log consumption, as in Constantinides and Duffie [1996. Asset pricing with heterogeneous consumers. Journal of Political Economy 104, 219–237]. We implement the new kernel on household consumption data from the Consumer Expenditure Survey (CEX). At monthly and quarterly horizons, the new kernel reconciles the premium on U.S. equities with the consumption of asset holders, for reasonable values of relative risk aversion. The new kernel also fares better than kernels based on the aggregation of intertemporal marginal rates of substitution in explaining the cross-sectional variation of risk premia on stocks and bonds. Portfolios mimicking changes in the cross-sectional variance of log consumption for asset holders command significant negative Sharpe ratios.
Information Quality and Endogenous Project Outcomes

In this paper, we examine the role of information quality in a setting in which a firm needs capital injection from a perfectly-competitive debt market to fund a profitable project. A representative creditor determines the debt repayment based on a noisy public signal about the project's state to break even, and the firm can make ex-post input to improve the project outcome. We find that higher information quality of the signal discourages the firm's input and thus decreases the overall efficiency. This result is mainly driven by the nature of debt contracting: the creditor cares more about the downside risk than the upside potential of the project outcome. When the information quality becomes higher, the creditor makes asymmetric adjustments in debt terms upon good and bad signals, thereby impacting the firm's input decisions asymmetrically upon different signals. Specifically, upon a bad signal, higher information quality significantly increases the debt repayment and thus discourages the firm's input, whereas upon a good signal, higher information quality does not reduce the debt repayment much and can barely encourage the firm's input. In addition, we find that this negative effect of higher information quality is even more pronounced when there is no information asymmetry between the firm and the creditor. This is because when the firm itself does not know its state, its input decision merely depends on the signal, whereas when the firm observes its state, its input decision relies less on the signal.
Measuring business cycles: A wavelet analysis of economic time series

Abstract Multiresolution wavelet analysis is a natural way to decompose an economic time series into trend, cycle, and noise. The method is illustrated with GDP data. The business-cycle component of the wavelet-filtered series closely resembles the series filtered by the approximate bandpass filter.
An atomistic model for the Navier slip condition

The behaviour of a fluid at the interface with a solid boundary is affected, to a large extent, by the potential landscape imposed on the fluid by the solid. Fluid slip at the interface with a solid boundary is modelled here as forced Brownian motion in a periodic potential landscape. The resulting model goes beyond simple transition-state-theory approaches and uses well-defined atomistic parameters to capture the salient features of the slip process in both the linear and nonlinear forcing regimes, yielding excellent agreement with molecular dynamics simulation results, as well as previous modelling results. An explicit expression for the Navier slip coefficient in terms of molecular-level system parameters is derived.
A Responsive-Pricing Retailer Sourcing from Competing Suppliers Facing Disruptions

Problem definition: We study a problem of a retailer that orders from competing strategic suppliers subject to independent or correlated disruptions and responds by setting the retail price on deli...
Effective Proximal Methods for Non-convex Non-smooth Regularized Learning

Sparse learning is a very important tool for mining useful information and patterns from high dimensional data. Nonconvex non-smooth regularized learning problems play essential roles in sparse learning, and have drawn extensive attentions recently. We design a family of stochastic proximal gradient methods by applying arbitrary sampling to solve the empirical risk minimization problem with a non-convex and non-smooth regularizer. These methods draw mini-batches of training examples according to an arbitrary probability distribution when computing stochastic gradients. A unified analytic approach is developed to examine the convergence and computational complexity of these methods, allowing us to compare the different sampling schemes. We show that the independent sampling scheme tends to improve performance over the commonly-used uniform sampling scheme. Our new analysis also derives a tighter bound on convergence speed for the uniform sampling than the best one available so far. Empirical evaluations demonstrate that the proposed algorithms converge faster than the state of the art.
Measuring Tax Authority Monitoring

Despite growing academic interest in tax authority monitoring, the literature remains lacking a summary measure of realized tax authority monitoring that can be constructed from firms’ publicly available financial statement information. The purpose of this study is to develop such a measure. Specifically, we view unrecognized tax benefit (UTB) releases due to settlements with the tax authority to indicate greater tax authority monitoring, and UTB releases due to lapses in the statute of limitations to indicate lesser tax authority monitoring. Among other tests, we validate a new measure of tax authority monitoring utilizing data from UTB releases by documenting its positive associations with predicted determinants of tax authority monitoring and by showing that it varies across time in expected ways. We believe our measure should be useful to future researchers studying tax authority monitoring in a variety of settings.
Morse-Smale characteristic foliations and convexity in contact manifolds

We generalize a result of Giroux which says that a closed surface in a contact $3$-manifold with Morse-Smale characteristic foliation is convex. Specifically, we show that the result holds in contact manifolds of arbitrary dimension. As an application, we show that a particular closed hypersurface introduced by A. Mori is $C^{\infty}$-close to a convex hypersurface.
Automatic conjecturing and proving of exact values of some infinite families of infinite continued fractions

Inspired by the recent pioneering work, dubbed “The Ramanujan Machine” by Raayoni et al. (The Ramanujan Machine: Automatically Generated Conjectures on Fundamental Constants. arXiv preprint. arXiv:1907.00205 , 2019), we (automatically) [rigorously] prove some of their conjectures regarding the exact values of some specific infinite continued fractions, and generalize them to evaluate infinite families (naturally generalizing theirs). Our work complements their beautiful approach, since we use symbolic rather than numeric computations, and we instruct the computer to not only discover such evaluations, but at the same time to prove them rigorously.
Childlessness and Social Support in Old Age in China.

Although previous studies showed that children are the primary source of old-age support in China, much less is known about the availability and sources of social support among childless elders. Also, little research has explored how older adults’ social support transitions over time by childless status. Using the 2005 and 2011 Chinese Longitudinal Healthy Longevity Survey (N = 14,575), this study examined the transition of living arrangement and sources of social support by childless status among adults aged 65 and older. A series of multinomial logistic and linear regression models were used to analyze the data. Results show that compared to elders with children, childless elders were more likely to live alone or in an institution at baseline, but their probability of living alone decreased substantially while that of living in an institution increased modestly in the 6-year follow-up. Moreover, childless elders generally had fewer support sources, but this disadvantage became smaller over time. Although childless elders were significantly more likely to depend on nobody, the spouse, grandchildren (or other relatives), or nonrelatives for support at baseline, this pattern disappeared in the follow-up likely due to mortality selection. Findings imply that although the risk of social isolation among childless elders becomes lower as age progresses, garnering more social resources at younger ages may help reduce their premature mortality.
Inhibition of CRISPR-Cas12a DNA targeting by nucleosomes and chromatin

Genome engineering nucleases must access chromatinized DNA. Here, we investigate how AsCas12a cleaves DNA within human nucleosomes and phase-condensed nucleosome arrays. Using quantitative kinetics approaches, we show that dynamic nucleosome unwrapping regulates target accessibility to Cas12a and determines the extent to which both steps of binding—PAM recognition and R-loop formation—are inhibited by the nucleosome. Relaxing DNA wrapping within the nucleosome by reducing DNA bendability, adding histone modifications, or introducing target-proximal dCas9 enhances DNA cleavage rates over 10-fold. Unexpectedly, Cas12a readily cleaves internucleosomal linker DNA within chromatin-like, phase-separated nucleosome arrays. DNA targeting is reduced only ~5-fold due to neighboring nucleosomes and chromatin compaction. This work explains the observation that on-target cleavage within nucleosomes occurs less often than off-target cleavage within nucleosome-depleted genomic regions in cells. We conclude that nucleosome unwrapping regulates accessibility to CRISPR-Cas nucleases and propose that increasing nucleosome breathing dynamics will improve DNA targeting in eukaryotic cells.
Social media engagement for global influencers

Consumers use social media to create content, generate online word-of-mouth, and communicate with brands and other consumers. Consumers engage with influencers who deliver content that is timely, e...
Stability and Robustness Analysis of Commensurate Fractional-Order Networks

Motivated by biochemical reaction networks, a generalization of the classical secant condition for the stability analysis of cyclic interconnected commensurate fractional-order systems is provided. The main result presents a sufficient condition for the stability of networks of cyclic interconnection of fractional-order systems when the digraph describing the network conforms to a single circuit. The condition becomes necessary under a special situation where coupling weights are uniform. We then investigate the robustness of fractional-order linear networks. Robustness performance of a fractional-order linear network is quantified using the $\mathcal H_2$ -norm of the dynamical system. The theoretical results are confirmed via some numerical illustrations.
Weight Prediction for Variants of Weighted Directed Networks

A weighted directed network (WDN) is a directed graph in which each edge is associated to a unique value called weight. These networks are very suitable for modeling real-world social networks in which there is an assessment of one vertex toward other vertices. One of the main problems studied in this paper is prediction of edge weights in such networks. We introduce, for the first time, a metric geometry approach to studying edge weight prediction in WDNs. We modify a usual notion of WDNs, and introduce a new type of WDNs which we coin the term almost-weighted directed networks (AWDNs). AWDNs can capture the weight information of a network from a given training set. We then construct a class of metrics (or distances) for AWDNs which equips such networks with a metric space structure. Using the metric geometry structure of AWDNs, we propose modified k nearest neighbors (kNN) methods and modified support-vector machine (SVM) methods which will then be used to predict edge weights in AWDNs. In many real-world datasets, in addition to edge weights, one can also associate weights to vertices which capture information of vertices; association of weights to vertices especially plays an important role in graph embedding problems. Adopting a similar approach, we introduce two new types of directed networks in which weights are associated to either a subset of origin vertices or a subset of terminal vertices. We, for the first time, construct novel classes of metrics on such networks, and based on these new metrics propose modified kNN and SVM methods for predicting weights of origins and terminals in these networks. We provide experimental results on several real-world datasets, using our geometric methodologies.
Contributions from resting state functional connectivity and familial risk to early adolescent-onset MDD: Results from the Adolescent Brain Cognitive Development study.

Abstract Background Family history of Major Depressive Disorder (MDD) is a robust predictor of MDD onset, especially in early adolescence. We examined the relationships between familial risk for depression and alterations to resting state functional connectivity (rsFC) within the default mode network (wDMN) and between the DMN and the left/right hippocampus (DMN-LHIPP/DMN-RHIPP) to the risk for early adolescent MDD onset. Methods We examined 9403 youth aged nine to eleven from the Adolescent Brain Cognitive Development study. Depressive symptoms were measured with the parent-reported Child Behavior Checklist. Both youth and their parents completed the Kiddie Schedule for Affective Disorders and Schizophrenia, which provided MDD diagnoses. A family history screen was administered to determine familial risk for depression. Youth underwent a resting state functional magnetic resonance imaging scan, providing us with rsFC data. Results Negative wDMN rsFC was associated with child-reported current depression, both child- and parent-reported past depression, and parent-reported current depressive symptoms. No difference was found in wDMN, DMN-LHIPP or DMN-RHIPP rsFC in children with or without familial risk for depression. Familial risk for depression interacted with wDMN rsFC in association with child-reported past MDD diagnosis and parent-reported current depressive symptoms. Limitations Information such as length of depressive episodes and age of onset of depression was not collected. Conclusions Altered wDMN rsFC in youth at familial risk for depression may be associated with increased risk for MDD onset in adolescence, but longitudinal studies are needed to test this hypothesis.
Approximating the two-level facility location problem via a quasi-greedy approach

We propose a quasi-greedy algorithm for approximating the classical uncapacitated 2-level facility location problem (2-LFLP). Our algorithm, unlike the standard greedy algorithm, selects a sub-optimal candidate at each step. It also relates the minimization 2-LFLP problem, in an interesting way, to the maximization version of the single level facility location problem. Another feature of our algorithm is that it combines the technique of randomized rounding with that of dual fitting.This new approach enables us to approximate the metric 2-LFLP in polynomial time with a ratio of 1.77, a significant improvement on the previously known approximation ratios. Moreover, our approach results in a local improvement procedure for the 2-LFLP, which is useful in improving the approximation guarantees for several other multi-level facility location problems. An additional result of our approach is an O(ln (n))-approximation algorithm for the non-metric 2-LFLP, where n is the number of clients. This is the first non-trivial approximation for a non-metric multi-level facility location problem.
Evaluating Appointment Postponement in Scheduling Patients at a Diagnostic Clinic

Diagnostic clinics are among healthcare facilities that suffer from long waiting times which can cause medical issues and lead to increases in patient no-shows. Reducing waiting times without significant capital investments is a challenging task. We tackle this challenge by proposing a new appointment scheduling policy for such clinics that does not require significant investments. The clinic in our study serves outpatients, inpatients, and emergency patients. Emergency patients must be seen on arrival, and inpatients must be given next day appointments. Outpatients, however, can be given later appointments. The proposed policy takes advantage of this by allowing the postponement of the acceptance of appointment requests from outpatients. The appointment scheduling process is modeled as a two-stage stochastic programming problem where a portion of the clinic capacity is allocated to inpatients and emergency patients in the first stage. In the second stage, outpatients are scheduled based on their priority classes. After a detailed analysis of the solutions obtained from the two-stage stochastic model, we develop a simple, non-anticipative policy for patient scheduling. We evaluate the performance of this proposed, easy-to-implement policy in a simulation study which shows significant improvements in outpatient indirect waiting times.
Spanner: Google’s Globally Distributed Database

Spanner is Google’s scalable, multiversion, globally distributed, and synchronously replicated database. It is the first system to distribute data at global scale and support externally-consistent distributed transactions. This article describes how Spanner is structured, its feature set, the rationale underlying various design decisions, and a novel time API that exposes clock uncertainty. This API and its implementation are critical to supporting external consistency and a variety of powerful features: nonblocking reads in the past, lock-free snapshot transactions, and atomic schema changes, across all of Spanner.
Calculation of therapeutic antibody viscosity with coarse-grained models, hydrodynamic calculations and machine learning-based parameters

High viscosity presents a challenge for manufacturing and drug delivery of therapeutic antibodies. The viscosity is determined by protein-protein interactions among many antibodies. Molecular simulation is a promising method to study protein-protein interactions; however, all-atom models do not allow the simulation of multiple molecules, which is necessary to compute viscosity directly. Coarse-grained models, on the other hand can do this. In this work, a 12-bead coarse-grained model based on Swan and coworkers (J. Phys. Chem. B 2018, 122, 2867-2880) was applied to study antibody interactions. Two adjustable parameters related to the short-range interactions on the variable and constant regions were determined by fitting experimental data of 20 IgG1 monoclonal antibodies at 150 mg/mL. The root-mean-square deviation improved from 1 to 0.68, and the correlation coefficient improved from 0.63 to 0.87 compared to that of a previous model that assumed the short-range interactions were the same for all the beads. Our model is also able to calculate the viscosity over a wide range of concentrations without additional parameters. A tabulated viscosity based on our model is provided to facilitate antibody screening in early-stage design.
Advantages of Bilinear Koopman Realizations for the Modeling and Control of Systems With Unknown Dynamics

Nonlinear dynamical systems can be made easier to control by lifting them into the space of observable functions, where their evolution is described by the linear Koopman operator. This letter describes how the Koopman operator can be used to generate approximate linear, bilinear, and nonlinear model realizations from data, and argues in favor of bilinear realizations for characterizing systems with unknown dynamics. Necessary and sufficient conditions for a dynamical system to have a valid linear or bilinear realization over a given set of observable functions are presented and used to show that every control-affine system admits an infinite-dimensional bilinear realization, but does not necessarily admit a linear one. Therefore, approximate bilinear realizations constructed from generic sets of basis functions tend to improve as the number of basis functions increases, whereas approximate linear realizations may not. To demonstrate the advantages of bilinear Koopman realizations for control, a linear, bilinear, and nonlinear Koopman model realization of a simulated robot arm is constructed from data. In a trajectory following task, the bilinear realization exceeds the prediction accuracy of the linear realization and the computational efficiency of the nonlinear realization when incorporated into a model predictive control framework.