cssi/SciSciGPT-SciSciNet huggingface dataset:
Do Patent Rights Regimes Matter

The paper asks whether exports are affected by importers’ patent rights regimes using a gravity trade equation. US export data to 71 countries from 1970 to 1992 are used. A two-way random-effects panel indicates that patent rights regimes per se do not matter; they matter with importing countries’ imitative abilities. For a country with an “average” imitative ability, US RD a unit increase in the patent rights index leads to a drop in US non-R&D-intensive exports by about 8–11%.
Resource Availability, Commitment and Environmental Reliability & Safety: A Study of Petroleum Refineries

This paper examines the effect of resource availability and resource commitment on several important regulatory measures related to environmental risk and safety performance in petrochemical manufacturing. The research is grounded in Normal Accident Theory, and it controls for the effect of interactive complexity and a coupling on environmental reliability. The study is based on a sample (n 570) of petroleum refineries located in the United States during the five-year period, 1993‐97. A statistically significant (p 5.01) relationship between resource availability and the incidence of accidental hazardous substance releases was observed. The study also identified a significant relationship between plant safety as measured by Total Case Incident Rates (TCIR) and resource availability. Surprisingly, no significant relationships were observed between accidental hazardous substance releases or safety related performance outcomes as measured by Total Case Incident Rates and resource commitment as capital spending related to health, environmental and safety in this sample of refineries.
Equilibrium selection in common-value second-price auctions

Abstract This note considers equilibrium selection in common-value second-price auctions with two bidders. We show that for each ex post equilibrium in continuous and undominated strategies, a sequence of “almost common-value” auctions can be constructed such that each of them possesses a unique undominated and continuous equilibrium and the corresponding sequence of equilibria converges to that ex post equilibrium. As an implication, no equilibrium selection of this model based on perturbations seems to be more convincing than others.
Characterizing the structure of optimal stopping policies

This paper studies a stochastic model of optimal stopping processes, which arise frequently in operational problems (e.g., when a manager needs to determine an optimal epoch to stop a process). For such problems, we propose an effective method of characterizing the structure of the optimal stopping policy for the class of discrete-time optimal stopping problems. Using this method, we also derive a set of metatheorems that can help identify when a threshold or control-band type stopping policy is optimal. We show that our proposed method can determine the structure of the optimal policy for some stopping problems that conventional methods fail to do so. In some cases, our method also simplifies the analysis of some existing results. Moreover, the metatheorems we propose help identify sufficient conditions that yield simple optimal policies when such policies are not generally optimal. We demonstrate these benefits by applying our method to several optimal stopping problems frequently encountered in, for example, the operations, marketing, finance, and economics literatures. We note that with structural results, optimal-stopping policies are easier to follow, describe, and compute and hence implement. They also help determine how a stopping policy should be adjusted in response to changes in the operational environment. In addition, as structural results are critical for the development of efficient algorithms to solve optimal stopping problems numerically, we hope that the method and results provided in the study will contribute to that effort. [ABSTRACT FROM AUTHOR]
Nudges that hurt those already hurting – distributional and unintended effects of salience nudges*

Abstract Nudges are becoming increasingly popular policy tools. Yet, distributional effects of nudges are largely unknown. We first design an economic laboratory experiment to examine the incidence of an opportunity cost reminder nudge (a salience nudge) designed to curb spending, while accounting for heterogeneity in emotional responses – specifically the pain of paying. Pain of paying is optimal for ‘unconflicted’ consumers, but too low for ‘spendthrifts’ and too high for ‘tightwads’, causing sub-optimal spending. Our empirical results imply the nudge increases pain of paying for tightwads, thereby reducing spending by tightwads, who already spend too little, while it entirely fails to reduce the spending of those who would have benefited from a spending reduction (spendthrifts). Overall, the nudge therefore might reduce consumer welfare. We next examine if the adverse impact of the opportunity cost reminder nudge is explained by a general tendency for all nudges to exacerbate peoples’ underlying spending preferences. We specifically test whether a salience nudge designed to boost spending correspondingly adversely affects spendthrifts? We unexpectedly find that subjects perceive the spending booster nudge as a “spending reminder”, which again, reduces spending by tightwads only, while not affecting spending by the other consumer types. Our results highlight two important aspects of salience nudges – given the complexity of consumer emotions and information processing, salience nudges can have undesired welfare effects, and the direction of their impact may be the opposite of what was intended.
Evaluating the Overall Technical Efficiency of Islamic Banks operating in the MENA Region during the Financial Crisis.

800x600 The present paper measured overall technical efficiency of Islamic banks operating in the MENA region during the financial crisis of 2007-2009 to address the question what are the levels of overall, pure technical and scale efficiency of Islamic banks operating in the MENA region and how they evolved during the financial crisis. This paper addresses this question technical, pure technical, and scale efficiency measures are analyzed by employing on-parametric technique, Data Envelopment Analysis (DEA). The study results suggested that Islamic banks in other MENA countries and North Africa on an average are relatively technically inefficient. This might be due to the underdeveloped banking system in those countries. In addition, the decomposition of technical efficiency into pure technical and scale efficiency shows that on average, the Islamic banks in North Africa counties and other MENA counties are having problems in the allocation of resources between their inputs and outputs mix compare to Islamic banks in GCC. Keywords: Islamic banks; DEA; Technical Efficiency; Scale Efficiency; GCC; MENA JEL Classifications: G01; G21; G24; G29 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";}
REITs and market friction

We examine differences in price delay for a sample of real estate investment trust (REIT) and non-REIT matched pairs. Results suggest an economically and statistically higher level of price delay for REIT securities, which implies heightened frictions that increase the time needed for new information to be impounded into the prices of REIT shares. The primary drivers for the observed delay differential include differences in idiosyncratic volatility, market risk, and the number of days traded. Within-REIT determinants of delay confirm findings for the pooled sample of matched pairs. Importantly, we infer find that REIT investors are not compensated for restricted information flow, as excess returns are unrelated to the price delay.
Earnings forecasting research: its implications for capital markets research

Abstract Since the early 1980s, earnings forecasting research has become much more closely aligned with capital markets research. Capital markets research requires a proxy for the (unobservable) market earnings expectation and earnings forecasting research has provided such proxy measures. Questions considered in this paper include: (1) if annual earnings follow a random walk or an IMA (1,1) model, does this mean that earnings changes cannot be predicted? (2) Do stock prices act as if quarterly earnings follow a seasonal random walk with drift process? (3) Is the predictive model which is best on the forecast accuracy dimension also best on the market association dimension? (4) How do analysts formulate their earnings expectations? (5) What is the role of earnings forecasting in ‘earnings response coefficient’ and ‘post-earnings announcement drift’ studies? (6) What is the likely role of earnings forecasting research in future capital market studies?
The Skill Content of Recent Technological Change: An Empirical Exploration

We apply an understanding of what computers do to study how computerization alters job skill demands. We argue that computer capital (1) substitutes for workers in performing cognitive and manual tasks that can be accomplished by following explicit rules; and (2) complements workers in performing nonroutine problem-solving and complex communications tasks. Provided these tasks are imperfect substitutes, our model implies measurable changes in the composition of job tasks, which we explore using representative data on task input for 1960 to 1998. We find that within industries, occupations and education groups, computerization is associated with reduced labor input of routine manual and routine cognitive tasks and increased labor input of nonroutine cognitive tasks. Translating task shifts into education demand, the model can explain sixty percent of the estimated relative demand shift favoring college labor during 1970 to 1998. Task changes within nominally identical occupations account for almost half of this impact.
Public health law: A communitarian perspective

American society has often favored individual rights disproportionately over the common good. In the aftermath of September 11, there is a need to readjust our criteria to allow for the strengthening of security, public safety, and public health policies. At the same time, we must assure that liberties are not trampled in the service of the common good. Clear criteria are needed to help determine when the proper balance has been reached. Although we should not expect that every public health policy will affect all members of society in exactly the same way, thought must be given to ways of compensating groups that are burdened more than others by a policy.
The Use of Road Infrastructure Data for Urban Transportation Planning: Issues and Opportunities.

This paper describes how, in order to maintain and improve road infrastructure in their respective jurisdictions, the state of Minnesota, the Minnesota Department of Transportation (MnDOT), the and seven counties in the Twin Cities Metropolitan area developed their respective decision making (investment) processes in which federal or local funding are periodically allocated to road projects, prioritized according to their funding needs based on measured road infrastructure conditions such as pavement quality, level of service, and safety. Including such an investment process in urban transportation planning enables forecasting changes to road infrastructure in the future. Periodic measures they adopt, for the management of road conditions. These measures, developed and maintained by engineers, however, are inconsistent with transportation planning models, causing difficulties in fully using infrastructure reports in planning practice. This paper addresses the issues encountered with regard to the use of road infrastructure reports in planning practice and identifies the opportunity to improve the inter-operability and integration of infrastructure reporting with urban transportation planning.
Pricing the US residential asset through the rent flow: A cross-sectional study

Abstract The paper explores how the standard consumption-CAPM fares in pricing housing returns and regional rental income streams in a cross-section of regions. In particular, we estimate the Euler equations associated with the gross housing returns inclusive of price appreciations and rents jointly for several metropolitan areas of the US. The representative agent has a Constant Relative Risk Aversion (CRRA) utility. The rent growth is allowed to depend on the business cycle. When biannual data from 1978 to 2007 is used, the parameter estimates are reasonable, and the model is not rejected. Large standard errors indicate uninformative estimates. The implied price rent ratio time series averages are similar to the data; however the model misses the boom-bust pattern in the prices. The model significantly understates the average and the variance of the price appreciations. Results are robust to allowing housing consumption directly in the utility function or using the Epstein–Zin–Weil utility.
The Equal Employment Opportunity Commission and Structural Reform of the American Workplace

In one of its most-watched recent cases, the United States Supreme Court struck down a class action alleging that Wal-Mart stores discriminated against female employees in pay and promotion decisions. The plaintiffs alleged that Wal-Mart’s corporate culture and highly discretionary decision-making practices led to sex discrimination on a company-wide basis, and they sought injunctive relief as well as backpay for individual employees. Reversing the Court of Appeals for the Ninth Circuit, the Supreme Court held in Wal-Mart v. Dukes that the proposed class failed to meet the requirements for class action certification under Rule 23 of the Federal Rules of Civil Procedure. Although the decision
Examining the Impact of Ranking on Consumer Behavior and Search Engine Revenue

In this paper, we study the effects of three different kinds of search engine rankings on consumer behavior and search engine revenues: direct ranking effect, interaction effect between ranking and product ratings, and personalized ranking effect. We combine a hierarchical Bayesian model estimated on approximately one million online sessions from Travelocity, together with randomized experiments using a real-world hotel search engine application. Our archival data analysis and randomized experiments are consistent in demonstrating the following: 1 A consumer-utility-based ranking mechanism can lead to a significant increase in overall search engine revenue. 2 Significant interplay occurs between search engine ranking and product ratings. An inferior position on the search engine affects “higher-class” hotels more adversely. On the other hand, hotels with a lower customer rating are more likely to benefit from being placed on the top of the screen. These findings illustrate that product search engines could benefit from directly incorporating signals from social media into their ranking algorithms. 3 Our randomized experiments also reveal that an “active” personalized ranking system wherein users can interact with and customize the ranking algorithm leads to higher clicks but lower purchase propensities and lower search engine revenue compared with a “passive” personalized ranking system wherein users cannot interact with the ranking algorithm. This result suggests that providing more information during the decision-making process may lead to fewer consumer purchases because of information overload. Therefore, product search engines should not adopt personalized ranking systems by default. Overall, our study unravels the economic impact of ranking and its interaction with social media on product search engines. This paper was accepted by Lorin Hitt, information systems.
Does Aid Matter? Measuring the Effect of Student Aid on College Attendance and Completion

Does student aid increase college attendance or simply subsidize costs for infra-marginal students? Settling the question empirically is a challenge, because aid is correlated with many characteristics that influence educational investment decisions. A shift in financial aid policy that affects some youth but not others can provide an identifying source of variation in aid. In 1982, Congress eliminated the Social Security Student Benefit Program, which at its peak provided grants totaling $3.7 billion a year to one out of ten college students. Using the death of a parent as a proxy for Social Security beneficiary status, I find that offering $1,000 ($1998) of grant aid increases educational attainment by about 0.16 years and the probability of attending college by four percentage points. The elasticities of attendance and completed years of college with respect to schooling costs are 0.7 to 0.8. The evidence suggests that aid has a 'threshold effect': a student who has crossed the hurdle of college entry with the assistance of aid is more likely to continue schooling later in life than one who has never attempted college. This is consistent with a model in which there are fixed costs of college entry. Finally, a cost-benefit analysis indicates that the aid program examined by this paper was a cost-effective use of government resources.
A Second Amendment Moment: The Constitutional Politics of Gun Control

This article tracks the development of gun rights in forty-four state constitutions, chronicles the wave of state legislation mandating nondiscretionary licenses to carry concealed firearms and offers a short history of our modern debate about private firearms with attention to the rise and fall of the handgun prohibition movement.
Forecasting the Future: An Assessment of the New Delaware General Corporations Law, Section 122(17)

This article considers the impact of the recent addition of section 122(17) to the Delaware General Corporations Law. The provision enables corporations to renounce, in advance, any interest or expectancy the corporation may have in specified business opportunities or specified classes of opportunities that come to the corporation or its officers, directors or shareholders. The article concludes that the amendment represents a sensible compromise in the debate between freedom of contract and mandatory rules, that it does not eliminate all fiduciary scrutiny and that it should not be preceived as a doctrinal aberration from fiduciary principles. The amendment no doubt also approaches a more level playing field with the freedom of other limited liability entities to opt out of default rules, but the cross-entity metaphor should not be normative in corporate law. The extent to which subsection (17) will work in practice depends much on its treatment in the courts.
Liquidity-saving mechanisms ☆

Abstract This paper studies the incentives of participants in a real-time gross settlement system with and without the addition of a liquidity-saving mechanism (LSM). Participants in the model face a liquidity shock and different costs for delaying payments. They trade off the cost of delaying a payment against the cost of borrowing liquidity from the central bank. The main contribution of the paper is to show that the design of an LSM has important implications for welfare. In particular, parameters determine whether the addition of an LSM increases or decreases welfare.
Adnostic: Privacy Preserving Targeted Advertising.

Online behavioral advertising (OBA) refers to the practice of tracking users across web sites in order to infer user interests and preferences. These interests and preferences are then used for selecting ads to present to the user. There is great concern that behavioral advertising in its present form infringes on user privacy. The resulting public debate — which includes consumer advocacy organizations, professional associations, and government agencies — is premised on the notion that OBA and privacy are inherently in conflict. In this paper we propose a practical architecture that enables targeting without compromising user privacy. Behavioral profiling and targeting in our system takes place in the user’s browser. We discuss the effectiveness of the system as well as potential social engineering and web-based attacks on the architecture. One complication is billing; ad-networks must bill the correct advertiser without knowing which ad was displayed to the user. We propose an efficient cryptographic billing system that directly solves the problem. We implemented the core targeting system as a Firefox extension and report on its effectiveness.
Security of property rights for whom

Property insecurity of non-elites can be compatible with or even enhance economic growth, but it also encourages conflict—which can undermine long-term growth and economic development. Using a new set of indicators which measure the property insecurity of marginalized ethno-cultural minority groups, this article demonstrates that the severity of property insecurity for the worst-off group in a country is strongly associated with the onset of armed conflict, and—once civil war is controlled for—property insecurity for marginalized minorities corresponds with higher growth rates. Economic growth can occur when the property rights of elites are secure but marginalized minorities face a high risk of expropriation, as land may be reallocated into the hands of investors with skills and access to capital. However, the potentially growth-enhancing effect of forced displacement and resettlement is reduced, because the property insecurity of minorities also increases the likelihood of armed conflict.
On Doctors and Judges

In convening the Conference on Measuring Judges and Justice and assembling this impressive Symposium, Dean David Levi and Professor Mitu Gulati urged the participating judges, political scientists, and law professors to "live in fragments no longer."1 Within that same spirit of cross-fertilization?aiming to forge dialogue across disciplines and seeking lessons from unfamiliar professions?I introduce in this Response some lessons from studying the medical profession. Relying on economics and sociology more than political science,2 I suggest that there is much to learn about judges from thinking about doctors. A superficial comparison between doctors and judges suggests that their social roles have much in common. Both wear austere
A New Era of Tax Enforcement: From 'Big Stick' to Responsive Regulation

This Article explores the economics of crime and compliance as the dominant approach to U.S. tax enforcement of the past three and a half decades. It evaluates the key advantages and disadvantages of the economic model as well as its application to tax. The Article then addresses the multiplicity of taxpayer behavior and the need and prospect of balancing the economically conceived methods of detection and punishment against other, more cooperative, means and developing a broader approach to tax enforcement more generally. The Article explores responsive regulation as a case study for an alternative method to tax enforcement that heavily draws on the economic paradigm but also supplements this approach with other theories, particularly those involving taxpayer identity, conflict escalation, and procedural justice. The Article suggests that this broader, more balanced, and closely tailored method of regulating responsively may enable regulators to draw on the advantages of the economic model while alleviating some of its drawbacks. Responsive regulation may therefore constitute a superior method for regulating tax compliance.
Comparing Predictive Accuracy

We propose and evaluate explicit tests of the null hypothesis of no difference in the accuracy of two competing forecasts. In contrast to previously developed tests, a wide variety of accuracy measures can be used (in particular, the loss function need not be quadratic and need not even be symmetric), and forecast errors can be non-Gaussian, nonzero mean, serially correlated, and contemporaneously correlated. Asymptotic and exact finite-sample tests are proposed, evaluated, and illustrated.
Economic freedom and the stability of stock prices: A cross-country analysis

Abstract This paper investigates the link between economic freedom and the price stability of individual securities in a unique setting. Using a sample of 327 American Depositary Receipts (ADRs), we find an inverse relation between the economic freedom of a ADRs' home country and the price volatility of the ADR. This negative correlation is driven primarily by certain components of economic freedom, such as property right protection, the soundness of the money, and the level of free trade in the home country. Further, we find evidence that less regulation and less government control of markets in the home country leads to more stable ADR prices.
The Highs and Lows of Wild Justice

This essay is a book review of Evan Mandery’s A Wild Justice: The Death and Resurrection of Capital Punishment in America, and Thane Rosenbaum’s Payback: The Case for Revenge. Mandery’s book is the story of the Supreme Court abolishing the death penalty in 1972’s Furman v. Georgia, and then legitimizing it four years later in Gregg v. Georgia. Rosenbaum’s book is an argument for revenge as an operative principle in our criminal justice system. In this review, I consider each book on its own terms. Mandery sets out to tell a story, and does it exceedingly well. Rosenbaum sets out to make an argument, and falls short by that criterion. Together, these two books — one named Wild Justice, and the other about wild justice — offer an opportunity to contemplate the retributivist viewpoint that anchors capital punishment today.
Alien Land Restrictions in the American Common Law: Exploring the Relative Autonomy Paradigm

This paper explores the judicial origins of alien land restrictions in the United States. Alien land restrictions originated in judge-made law, and until the later part of the nineteenth century continued to be dominated by the common law. Legislators and framers of Constitutions in the early American republic left to judges the task of enumeration of rights to accompany the status of "citizen". The gap in our understanding of this process is widened by the failure thus far to explore the importance of judicial decisions that restricted fee simple ownership of land to citizens. As a source of law, state and federal courts in the United States adopted an English common-law rule, seemingly oblivious to the incongruity of applying a rule by which a monarch governed subjects to the political context of the newly formed United States. Among other restrictions, the common law rule required that real property held by an alien automatically escheated to the state upon his death, even if his or her heirs were American citizens. Courts frequently enforced escheat of land following an alien's death, sometimes decades later, and often to the detriment of citizens who claimed title to the property. Judges continued to protect the common-law doctrine in the face of attempts to construct alternative landholding mechanisms, becoming stalwart protectors of their presumed ideal that all landholders should be citizens. This study of judicial enforcement of the common law of alien land rights leads to both general and specific observations about the nature and effect of judicial method in the nineteenth century. Among the general observations, I argue that these cases provide important evidence of the controversial paradigm of the "relative autonomy of law". Judges in this period were largely unconcerned that forfeitures could result in a chaotic market economy for land, especially in periods in which large percentages of the inhabitants were foreign-born. I suggest that the tenacity of a taught legal tradition helps to explain the staying power of legal doctrine in the face of social forces we might expect to lead to change; namely, that the underlying doctrine withstood social forces that tended toward rationalization of property law in other contexts.
Better financial reporting: Meanings and means

Abstract What is the meaning of better corporate financial reporting? How can financial reporting be improved? There are many claims of shortcomings of financial reporting. Conflicts among these claims point to the political elements of the problem inherent in collective choice in a society. Since “better” depends on the interest group whose perspective is chosen for analysis, politics lies at the heart of accounting policy. The set of possible means of arriving to any agreed upon meaning of “better” includes not only regulation, but also social norms and market competition. Judiciously combining all three approaches, instead of relying on any one alone, may help us improve financial reporting. This paper examines the meaning and means of better financial reporting.
Do the size, value, and momentum factors drive stock returns in emerging markets?

Abstract This paper investigates the size, value, and momentum effects in 18 emerging stock markets during the period 1990–2013. We find that size and momentum strategies generally fail to generate superior returns in emerging markets. The value effect exists in all markets except Brazil, and it is robust to different periods and market conditions. Value premiums tend to move positively together across different markets, and such inter-market comovements increase overtime and during the global financial crisis.
Minorities and Storable Votes

The paper studies a simple voting system that can increase the power of minorities without sacrificing aggregate efficiency or treating voters asymmetrically. Storable votes grant each voter a stock of votes to spend as desired over a series of binary decisions and thus elicit voters’ strength of preferences. The potential of the mechanism is particularly clear in the presence of systematic minorities: by accumulating votes on issues that it deems most important, the minority can win occasionally. But because the majority typically can outvote it, the minority wins only if its strength of preference is high and the majority’s strength of preference is low. The result is that the minority’s preferences are represented, while aggregate efficiency either falls little or in fact rises, relative to simple majority voting. The theoretical predictions of our model are confirmed by a series of experiments: the frequency of minority victories, the relative payoff of the minority versus the majority, and the aggregate payoffs all match the theory.
The role of the media in corporate governance: Do the media influence managers' capital allocation decisions?

Abstract Using 636 large acquisition attempts that are accompanied by a negative stock price reaction at their announcement (“value-reducing acquisition attempts”) from 1990 to 2010, we find that, in deciding whether to abandon a value-reducing acquisition attempt, managers' sensitivity to the firm's stock price reaction at the announcement is influenced by the level and the tone of media attention to the proposed transaction. We interpret the results to imply that managers have reputational capital at risk in making corporate capital allocation decisions and that the level and tone of media attention heighten the impact of a value-reducing acquisition on the managers' reputational capital. To the extent that value-reducing acquisition attempts are more likely to be abandoned, the media can play a role in aligning managers' and shareholders' interests.
The Great and Mighty Tax Law: How the Roberts Court Has Reduced Constitutional Scrutiny of Taxes and Tax Expenditures

This article compares National Federation of Independent Business v. Sebelius – the Supreme Court’s decision upholding the individual mandate in Obamacare as a tax, with Arizona Christian Schools v. Winn – the Supreme Court’s decision denying standing to taxpayers with an Establishment Clause challenge to a state tax credit. It argues that these cases aggravate a growing tension between the economic and legal analyses of taxation by reducing the legal significance of economic analysis in constitutional cases. It suggests that Arizona Christian Schools was a truly radical decision because it conceptualized tax expenditures as private action immune from constitutional attack, rather than state action subject to constitutional limitations, making tax expenditures legally invisible. The article parses the Court’s economic and legal approach, and contends that the Court misunderstood the important issues. It explains how tax cuts are distinguishable from spending through the tax law, and why tax expenditures – in the aggregate – should be legally important. It argues that the Court’s approach to tax expenditures not only reduces the fundamental protection that the Constitution guarantees individuals, but also has other troubling legal and policy implications. These decisions weaken the revenue-raising role of taxation, blur the conceptual structure of the tax law, and undermine the tax reform efforts of other branches of government. They jeopardize established legal doctrine by destabilizing the precedents on unconstitutional conditions attached to tax benefits, which depend on conceiving tax benefits as government subsidies or privileges. These decisions encourage legislatures to adopt provisions that favor high-income taxpayers, while discouraging transparent and equitable government. They make the tax law uniquely powerful.
Data-driven prediction of the equivalent sand-grain height in rough-wall turbulent flows

This paper investigates a long-standing question about the effect of surface roughness on turbulent flow: What is the equivalent roughness sand-grain height for a given roughness topography? Deep neural network (DNN) and Gaussian process regression (GPR) machine learning approaches are used to develop a high-fidelity prediction approach of the Nikuradse equivalent sand-grain height with an average error of less than 10 % and a maximum error of less than 30 %, which appears to be significantly more accurate than existing prediction formulae. They also identified the surface porosity and the effective slope of roughness in the spanwise direction as important factors in drag prediction.
Investigation of BERT Model on Biomedical Relation Extraction Based on Revised Fine-tuning Mechanism

With the explosive growth of biomedical literature, designing automatic tools to extract information from the literature has great significance in biomedical research. Recently, transformer-based BERT models adapted to the biomedical domain have produced leading results. However, all the existing BERT models for relation classification only utilize partial knowledge from the last layer. In this paper, we will investigate the method of utilizing the entire layer in the fine-tuning process of BERT model. To the best of our knowledge, we are the first to explore this method. The experimental results illustrate that our method improves the BERT model performance and outperforms the state-of-the-art methods on three benchmark datasets for different relation extraction tasks. In addition, further analysis indicates that the key knowledge about the relations can be learned from the last layer of BERT model.
Climate change and the impact of extreme temperatures on aviation

Temperature and airport elevation significantly influence the maximum allowable takeoff weight of an aircraft by changing the surface air density and thus the lift produced at a given speed. For a given runway length, airport elevation, and aircraft type, there is a temperature threshold above which the airplane cannot take off at its maximum weight and thus must be weight restricted. The number of summer days necessitating weight restriction has increased since 1980 along with the observed increase in surface temperature. Climate change is projected to increase mean temperatures at all airports and to significantly increase the frequency and severity of extreme heat events at some. These changes will negatively affect aircraft performance, leading to increased weight restrictions, especially at airports with short runways and little room to expand. For a Boeing 737-800 aircraft, it was found that the number of weight-restriction days between May and September will increase by 50%-200% at four major airports in the United States by 2050-70 under the RCP8.5 emissions scenario. These performance reductions may have a negative economic effect on the airline industry. Increased weight restrictions have previously been identified as potential impacts of climate change, but this study is the first to quantify the effect of higher temperatures on commercial aviation. Planning for changes in extreme heat events will help the aviation industry to reduce its vulnerability to this aspect of climate change.
Tau Forms Oligomeric Complexes on Microtubules that are Distinct from Pathological Oligomers in Disease

Tau is a microtubule-associated protein, which facilitates the assembly and stability of neuronal microtubules in humans. Accumulation of tau into insoluble aggregates known as neurofibrillary tangles (NFTs) is a pathological hallmark of several neurodegenerative diseases. The current hypothesis is that small, soluble oligomeric tau species preceding NFT formation could be causing loss of tau function and toxicity. Here, using single molecule localization microscopy (SMLM), we show that, in vivo, tau forms small oligomers on microtubules under physiological conditions. These physiological oligomers are distinct from pathological oligomers and could be pre-cursors of aggregation in pathology. Further, using SMLM and an unsupervised shape classification algorithm that we developed, we show that different tau phosphorylation states are associated with distinct higher order aggregate species in pathology. Our work elucidates tau9s nanoscale composition under physiological and pathological conditions in vivo.
{REMIX}: Efficient Range Query for LSM-trees

LSM-tree based key-value (KV) stores organize data in a multi-level structure for high-speed writes. Range queries on traditional LSM-trees must seek and sort-merge data from multiple table files on the fly, which is expensive and often leads to mediocre read performance. To improve range query efficiency on LSM-trees, we introduce a space-efficient KV index data structure, named REMIX, that records a globally sorted view of KV data spanning multiple table files. A range query on multiple REMIX-indexed data files can quickly locate the target key using a binary search, and retrieve subsequent keys in sorted order without key comparisons. We build RemixDB, an LSM-tree based KV-store that adopts a write-efficient compaction strategy and employs REMIXes for fast point and range queries. Experimental results show that REMIXes can substantially improve range query performance in a write-optimized LSM-tree based KV-store.
Visual Aware Hierarchy Based Food Recognition.

Food recognition is one of the most important components in image-based dietary assessment. However, due to the different complexity level of food images and inter-class similarity of food categories, it is challenging for an image-based food recognition system to achieve high accuracy for a variety of publicly available datasets. In this work, we propose a new two-step food recognition system that includes food localization and hierarchical food classification using Convolutional Neural Networks (CNNs) as the backbone architecture. The food localization step is based on an implementation of the Faster R-CNN method to identify food regions. In the food classification step, visually similar food categories can be clustered together automatically to generate a hierarchical structure that represents the semantic visual relations among food categories, then a multi-task CNN model is proposed to perform the classification task based on the visual aware hierarchical structure. Since the size and quality of dataset is a key component of data driven methods, we introduce a new food image dataset, VIPER-FoodNet (VFN) dataset, consists of 82 food categories with 15k images based on the most commonly consumed foods in the United States. A semi-automatic crowdsourcing tool is used to provide the ground-truth information for this dataset including food object bounding boxes and food object labels. Experimental results demonstrate that our system can significantly improve both classification and recognition performance on 4 publicly available datasets and the new VFN dataset.
Unraveling excitation energy transfer assisted by collective behaviors of vibrations

We investigate how collective behaviors of vibrations such as cooperativity and interference can enhance energy transfer in a nontrivial way, focusing on an example of a donor-bridge-acceptor trimeric chromophore system coupled to two vibrational degrees of freedom. Employing parameters selected to provide an overall uphill energy transfer from donor to acceptor, we use numerical calculations of dynamics in a coupled exciton-vibration basis, together with perturbation-based analytics and calculation of vibronic spectra, we identify clear spectral features of single- and multi-phonon vibrationally-assisted energy transfer (VAET) dynamics, where the latter include up to six-phonon contributions. We identify signatures of vibrational cooperation and interference that provide enhancement of energy transfer relative to that obtained from VAET with a single vibrational mode. We observe a phononic analogue of two-photon absorption, as well as a novel heteroexcitation mechanism in which a single phonon gives rise to simultaneous excitation of both the trimeric system and the vibrational degrees of freedom. The impact of vibrations and of the one- and two-phonon VAET processes on the energy transfer are seen to be quite different in the weak and strong site-vibration coupling regimes. In the weak coupling regime, two-phonon processes dominate, whereas in the strong coupling regime up to six-phonon VAET processes can be induced. The VAET features are seen to be enhanced with increasing temperature and site-vibration coupling strength, and are reduced in the presence of dissipation. We analyze the dependence of these phenomena on the explicit form of the chromophore-vibration couplings, with comparison of VAET spectra for local and non-local couplings.
1I/‘Oumuamua as an N2 Ice Fragment of an exo-Pluto Surface: I. Size and Compositional Constraints

The origin of the interstellar object 1I/'Oumuamua has defied explanation. We perform calculations of the non-gravitational acceleration that would be experienced by bodies composed of a range of different ices and demonstrate that a body composed of N2 ice would satisfy the available constraints on the non-gravitational acceleration, size and albedo, and lack of detectable emission of CO or CO2 or dust. We find that 'Oumuamua was small, with dimensions 45 m x 44 m x 7.5 m at the time of observation at 1.42 au from the Sun, with a high albedo of 0.64. This albedo is consistent with the N2 surfaces of bodies like Pluto and Triton. We estimate 'Oumuamua was ejected about 0.4-0.5 Gyr ago from a young stellar system, possibly in the Perseus arm. Objects like 'Oumuamua may directly probe the surface compositions of a hitherto-unobserved type of exoplanet: "exo-plutos". In a companion paper (Desch & Jackson, 2021) we demonstrate that dynamical instabilities like the one experienced by the Kuiper belt, in other stellar systems, plausibly could generate and eject large numbers of N2 ice fragments. 'Oumuamua may be the first sample of an exoplanet brought to us.
Atypical exit events near a repelling equilibrium

We consider exit problems for small, white noise perturbations of a dynamical system generated by a vector field and a domain containing a critical point with all positive eigenvalues of linearization. We prove that, in the vanishing noise limit, the probability of exit through a generic set on the boundary is asymptotically polynomial in the noise strength with exponent depending on the mutual position of the set and the flag of the invariant manifolds associated with the top eigenvalues. Furthermore, we compute the limiting exit distributions conditioned on atypical exit events of polynomially small probability and show that the limits are Radon–Nikodym equivalent to volume measures on certain manifolds that we construct. This situation is in sharp contrast with the large deviation picture where the limiting conditional distributions are point masses.
Generating Cryptographically-Strong Random Lattice Bases and Recognizing Rotations of $\mathbb {Z}^n$.

Lattice-based cryptography relies on generating random bases which are difficult to fully reduce. Given a lattice basis (such as the private basis for a cryptosystem), all other bases are related by multiplication by matrices in \(GL(n,\mathbb {Z})\). We compare the strengths of various methods to sample random elements of \(GL(n,\mathbb {Z})\), finding some are stronger than others with respect to the problem of recognizing rotations of the \(\mathbb {Z}^n\) lattice. In particular, the standard algorithm of multiplying unipotent generators together (as implemented in Magma’s RandomSLnZ command) generates instances of this last problem which can be efficiently broken, even in dimensions nearing 1,500. Likewise, we find that the random basis generation method in one of the NIST Post-Quantum Cryptography competition submissions (DRS) generates instances which can be efficiently broken, even at its 256-bit security settings. Other random basis generation algorithms (some older, some newer) are described which appear to be much stronger.
Computationally efficient likelihood inference in exponential families when the maximum likelihood estimator does not exist

In a regular full exponential family, the maximum likelihood estimator (MLE) need not exist in the traditional sense. However, the MLE may exist in the completion of the exponential family. Existing algorithms for finding the MLE in the completion solve many linear programs; they are slow in small problems and too slow for large problems. We provide new, fast, and scalable methodology for finding the MLE in the completion of the exponential family. This methodology is based on conventional maximum likelihood computations which come close, in a sense, to finding the MLE in the completion of the exponential family. These conventional computations construct a likelihood maximizing sequence of canonical parameter values which goes uphill on the likelihood function until they meet a convergence criteria. Nonexistence of the MLE in this context results from a degeneracy of the canonical statistic of the exponential family, the canonical statistic is on the boundary of its support. There is a correspondance between this boundary and the null eigenvectors of the Fisher information matrix. Convergence of Fisher information along a likelihood maximizing sequence follows from cumulant generating function (CGF) convergence along a likelihood maximizing sequence, conditions for which are given. This allows for the construction of necessarily one-sided confidence intervals for mean value parameters when the MLE exists in the completion. We demonstrate our methodology on three examples in the main text and three additional examples in an accompanying technical report. We show that when the MLE exists in the completion of the exponential family, our methodology provides statistical inference that is much faster than existing techniques.
Optimal Sensing Precision in Ensemble and Unscented Kalman Filtering

Abstract We consider the problem of selecting an optimal set of sensor precisions to estimate the states of a non-linear dynamical system using an Ensemble Kalman filter and an Unscented Kalman filter, which uses random and deterministic ensembles respectively. Specifically, the goal is to choose at run-time, a sparse set of sensor precisions for active-sensing that satisfies certain constraints on the estimated state covariance. In this paper, we show that this sensor precision selection problem is a semidefinite programming problem when we use l1 norm over precision vector as the surrogate measure to induce sparsity. We formulate a sensor selection scheme over multiple time steps, for certain constraints on the terminal estimated state covariance.