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Studies the tension between the claim that Article V of the U.S. Constitution articulates the exclusive procedure by which the Constitution may be amended and the historical commitment of the U.S. to the ideal that the people are sovereign. Background on Article V; Political positions on the resolution of Representative Thomas Corwin of Ohio to amend the U.S. Constitution; Efficacy of the Corwin amendment.

In this paper, the pure strategy subgame perfect equilibria of a general class of stopping time games are studied. It is shown that there always exists a natural class of Markov Perfect Equilibria, called stopping equilibria. Such equilibria can be computed as a solution of a single agent stopping time problem, rather than of a fixed point problem. A complete characterization of stopping equilibria is presented. Conditions are given under which the outcomes of such equilibria span the set of all possible outcomes from perfect equilibria. Two economic applications of the theory, product innovations and the timing of asset sales, are discussed. [ABSTRACT FROM AUTHOR]

The COVID-induced recession began in March 2020 for the United States. We identify this turning point by applying a Bayesian sequential quickest detection method to a real-time index of economic activity. Supporting evidence is also found from macroeconomic data releases and stock markets. [ABSTRACT FROM AUTHOR]

In recent years, advanced regularization techniques have emerged as a powerful tool aimed at stable estimation of infectious disease parameters that are crucial for future projections, prevention, and control. Unlike other system parameters, i.e., incubation and recovery rates, the case reporting rate, J, and the time-dependent effective reproduction number, Re(t), are directly influenced by a large number of factors making it impossible to pre-estimate these parameters in any meaningful way. In this study, we propose a novel iteratively-regularized trust-region optimization algorithm, combined with SuSvIuIvRD compartmental model, for stable reconstruction of J and Re(t) from reported epidemic data on vaccination percentages, incidence cases, and daily deaths. The innovative regularization procedure exploits (and takes full advantage of) a unique structure of the Jacobian and Hessian approximation for the nonlinear observation operator. The proposed inversion method is thoroughly tested with synthetic and real SARS-CoV-2 Delta variant data for different regions in the United States of America from July 9, 2021, to November 25, 2021. Our study shows that case reporting rate during the Delta wave of COVID-19 pandemic in the US is between 12% and 37%, with most states being in the range from 15% to 25%. This confirms earlier accounts on considerable under-reporting of COVID-19 cases due to the impact of "silent spreaders" and the limitations of testing. [ABSTRACT FROM AUTHOR]

In a general discrete-time market model with proportional transaction costs, we derive new expectation representations of the range of arbitrage-free prices of an arbitrary American option. The upper bound of this range is called the upper hedging price, and is the smallest initial wealth needed to construct a self-financing portfolio whose value dominates the option payoff at all times. A surprising feature of our upper hedging price representation is that it requires the use of randomized stopping times (Baxter and Chacon 1977), just as ordinary stopping times are needed in the absence of transaction costs. We also represent the upper hedging price as the optimum value of a variety of optimization problems. Additionally, we show a two-player game where at Nash equilibrium the value to both players is the upper hedging price, and one of the players must in general choose a mixture of stopping times. We derive similar representations for the lower hedging price as well. Our results make use of strong duality in linear programming. [ABSTRACT FROM AUTHOR]

Methamphetamine (METH) and 3,4‐methylenedioxymethamphetamine (MDMA) are common drugs of abuse and driving under their influence may occur in 1 million people yearly in the United States. This systematic review fills the currently unmet need in understanding the effects of METH and MDMA on motor vehicle driving performance (MVP) and provides insight into the forensic community. A PubMed search on September 24, 2020, for experimental and observational studies, which evaluated the impact of METH and MDMA on MVP was performed. After a review of 208 abstracts, 103 were considered potentially interesting and full texts were obtained. After the exclusion of non‐English articles, review articles, single case reports, and articles which did not evaluate METH or MDMA on MVP, a total of nine experimental studies, 10 traditional observational studies, and 35 case series were included. The clinical rigor of experimental studies was evaluated using the Jadad scale. Experimental studies often demonstrated no significant MVP safety signals for METH or MDMA use, which was contrary to the overwhelming MVP safety risks found in observational studies. Common driving behaviors while using METH or MDMA include: errors in judgment, traveling at high speeds, failure to stop, merging inappropriately, lane weaving, and crashes. Limitations of experimental studies that led to dissimilar MVP outcomes from observational studies include: the common use of driving simulators, as opposed to actual driving examinations, and doses of METH or MDMA administered may not be representative of blood concentrations seen in observational studies. This systematic review has no funding source and was not registered. [ABSTRACT FROM AUTHOR]

Capital structure optimization is a key aspect to ensure the success of infrastructure financing. Interest in capital structure optimization in infrastructure projects has been growing rapidly because of the prevalence of public-private partnerships in the U.S. and private finance initiative in the United Kingdom. Even though it is recognized that there are three types of financial sources (i.e., equity, mezzanine, and debt capital) in funding an infrastructure project, the traditional capital structure optimization method either did not consider the existence of mezzanine finance or treat it to be debt or equity instruments. This assumption is not valid in the new era when more and more inflows of capital into infrastructure development projects are from all kinds of institutional investors and multilateral development finance institutions through private equity-style funds. These new equity investors are willing to take advantage of mezzanine financial instruments and common shares as a vehicle to invest in infrastructure assets, which makes a huge difference with traditional equity providers. The frequent implementation of convertible security as one kind of mezzanine financial instrument makes the prediction of the evolution of capital structure impossible due to the dynamic stopping time of the contingent claim embedded in convertible security. Thus, the traditional method for capital structure optimization in the new era is not tenable any more. The principal objective of this article is to present a new model from the perspective of project promoters, which considers convertible security in infrastructure financing and identifies optimal mix of equity, debt, mezzanine capital by incorporating stochastic dynamic programming into the traditional approach. [ABSTRACT FROM AUTHOR]

In the discrete binomial model for option pricing, the price of an American option is obtained using a backward recursion algorithm. However, the currently available justification for this algorithm is long and circuitous. Similarly, the key result used in the justification for antithetic sampling is not proved in standard financial texts. The proof is relegated to an older article, where the required result is masked by general details about association of random variables. This article gives self-contained, considerably simpler, proofs for both these basic results and extends these results to more general applications. In particular, it settles the question of optimality of early shouting for the buyer of Shout call options. [ABSTRACT FROM AUTHOR]

In the United States, approximately 7000 rare diseases affect 30 million patients, and only 10% of these diseases have existing therapies. Sound study design and causal inference methods are essential to demonstrate the therapeutic efficacy, safety, and effectiveness of new therapies. In the rare diseases setting, several factors challenge the use of typical parallel control designs: the small patient population size, genotypic and phenotypic diversity, and the complexity and incomplete understanding of the disorder's progression. Repeated measures, when spaced appropriately relative to disease progression and exploited in design and analysis, can increase study power and reduce variability in treatment effect estimation. This paper reviews these longitudinal designs and draws the parallel between some new and existing randomized studies in rare diseases and their less well-known controlled observational study designs. We show that self-controlled randomized crossover and N-of-1 designs have similar considerations as the observational case series and case-crossover designs. Also, randomized sequential designs have similar considerations to longitudinal cohort studies using sequential matching or weighting to control confounding. We discuss design and analysis considerations for valid causal inference and illustrate them with examples of analyses in multiple rare disorders, including urea cycle disorder and cystic fibrosis. [ABSTRACT FROM AUTHOR]

Since 1996, the Central Bank of México issues a put option in order to buy American Dollars as a way of increasing its international reserves. This is an exotic option that gives the right to the Mexican banks to sell this currency to the Central Bank at the price of the day before the date of exercise. The option has a maturity of one month and can be exercised on any day during this period, subject to an additional condition that depends on the average price of the Dollar during the previous 20 days. In this work we study the valuation and the optimal time of exercise of this option under the Binomial and the Black--Scholes Models. The optimal time of exercise is found for the Binomial model and a rule of exercise is proposed for the Black--Scholes Model. Numerical results are included to illustrate the performance of this rule of exercise. [ABSTRACT FROM AUTHOR]

Consider a model of a financial market with a stock driven by a Lévy process and constant interest rate. A closed formula for prices of perpetual American call options in terms of the overall supremum of the Lévy process, and a corresponding closed formula for perpetual American put options involving the infimum of the after-mentioned process are obtained. As a direct application of the previous results, a Black-Scholes type formula is given. Also as a consequence, simple explicit formulas for prices of call options are obtained for a Lévy process with positive mixed-exponential and arbitrary negative jumps. In the case of put options, similar simple formulas are obtained under the condition of negative mixed-exponential and arbitrary positive jumps. Risk-neutral valuation is discussed and a simple jump-diffusion model is chosen to illustrate the results. [ABSTRACT FROM AUTHOR]

The SARS-CoV-2 pandemic led to closure of nearly all K-12 schools in the United States of America in March 2020. Although reopening K-12 schools for in-person schooling is desirable for many reasons, officials understand that risk reduction strategies and detection of cases are imperative in creating a safe return to school. Furthermore, consequences of reclosing recently opened schools are substantial and impact teachers, parents, and ultimately educational experiences in children. To address competing interests in meeting educational needs with public safety, we compare the impact of physical separation through school cohorts on SARS-CoV-2 infections against policies acting at the level of individual contacts within classrooms. Using an age-stratified Susceptible-Exposed-Infected-Removed model, we explore influences of reduced class density, transmission mitigation, and viral detection on cumulative prevalence. We consider several scenarios over a 6-month period including (1) multiple rotating cohorts in which students cycle through in-person instruction on a weekly basis, (2) parallel cohorts with in-person and remote learning tracks, (3) the impact of a hypothetical testing program with ideal and imperfect detection, and (4) varying levels of aggregate transmission reduction. Our mathematical model predicts that reducing the number of contacts through cohorts produces a larger effect than diminishing transmission rates per contact. Specifically, the latter approach requires dramatic reduction in transmission rates in order to achieve a comparable effect in minimizing infections over time. Further, our model indicates that surveillance programs using less sensitive tests may be adequate in monitoring infections within a school community by both keeping infections low and allowing for a longer period of instruction. Lastly, we underscore the importance of factoring infection prevalence in deciding when a local outbreak of infection is serious enough to require reverting to remote learning. [ABSTRACT FROM AUTHOR]

Soccer exposes players to head injuries and involves repeated intentional head impacts through heading the ball. Our objective was to investigate the rate of both intentional headers and involuntary head impacts in semiprofessional male soccer players during one season. In this prospective cohort study, we followed 54 men (16–35 years) playing in two soccer clubs participating in the same regional French championship throughout the 2017–2018 season. All head impacts that occurred in competitive games were analyzed using video recordings. Player position, game exposure, referee's decision were also reported. Head impact incidence rate (IR) per 1000 player-hours, with the 95% confidence intervals (CIs) were calculated. Results: Headers IR was 3584.7 per 1000 player-hours (95% CI = 3431.9, 3737.5). Forwards and center-backs performed a higher number of headers. Involuntary head impacts IR was 44.1/1000 player-hours (95% CI = 27.1, 60.9). Just under half led the referee to stop playing time for a caregiver examination. Three concussions with a loss of consciousness after a head-to-head impact in a heading duel were recorded. Conclusions: Intentional headers were relatively common, contrary to involuntary head impacts that were however mainly due to heading duels. Head-to-head impact should lead to a systematic exit from the game for suspicion of concussion. [ABSTRACT FROM AUTHOR]

Student teachers' instructional planning requires them to regulate certain aspects of their own learning while designing lessons. The aim of this study is to support student teachers' self‐regulated learning through the convergence effect, where network‐based tutors are designed to optimize system recommendations of online resources based on information‐seeking behaviours. A total of 68 student teachers were randomly assigned to either a dynamic or static version of nBrowser, which converged a network or not towards an optimal configuration. The structural equation model suggests that student teachers spent less time during the learning session using the dynamic version of nBrowser. Although student teachers were found to be more efficient in seeking and acquiring information and reported knowledge gains, they failed to perform better than those assigned to the static condition on the lesson plan design task. We discuss the implications for the convergence effect in the context of network‐based tutors. Lay Description: What is already known about this topic: Preservice teachers require resources to plan classroom activities, for example, open educational resources available on the web.Preservice teachers may lack the prerequisite skills to regulate their own learning, in particular, to seek and acquire information from online resources in an efficient manner.Computer‐based learning environments can be designed to support self‐regulated learning while navigating hypermedia. What this paper adds: Intelligent web browsers can leverage the linguistic features and information‐seeking behaviours of preservice teachers to personalize recommendations of online resources.Recommender systems stands to improve the efficiency of teachers' self‐regulated learning, in particular, their efforts to seek and acquire online resources. Implications for practice and/or policy: Efforts should be made to make artificial intelligence tools in education broadly available to teachers, including lesson planning tools that leverage open educational resources.Tools that support teachers in seeking and acquiring information may benefit their professional development by enabling them to allocate more attentional resources to other aspects of teaching. [ABSTRACT FROM AUTHOR]

The article examines the application of obscenity law in comic books in the U.S. Topics mentioned include the legal issues associated with pornography and graphic visuals featured in comic books, the definition of obscenity, the difference between obscenity and pornography, and the interpretation of freedom of speech in the First Amendment.

Within a year or two, the thirty-eighth state is likely to ratify the Equal Rights Amendment (ERA), setting up an unprecedented constitutional challenge. The ERA was proposed with a seven-year deadline in the resolving clause, establishing the mode of ratification. That was a shift from earlier precedents in which a deadline had been placed in the text of the amendment proposal itself. Article V is annoyingly silent on the issue of congressional deadlines in amendment proposals, and the Supreme Court has never addressed the issue of a deadline that could void an otherwise properly ratified amendment. The practice of placing deadlines on amendment proposals began in 1917 with the Eighteenth Amendment, but has not been consistent since. Deadlines appear to have originated as an effort to torpedo amendments by opponents, but have since become almost pro forma. Some argue deadlines ensure finality and closure; others argue they infringe on the power of states to control the ratification process free of unconstitutional limitations imposed by the national legislature. With the 1992 ratification of the Twenty-Seventh Amendment after 203 years, and state ratifications of the ERA after 35 years, the issue of congressional deadlines is both front and center and of potentially enormous consequence. This Article examines the history, theory, and policy of amendment deadlines and argues that they are unconstitutional limitations on state power, inconsistent with the federalism guarantees of the founding. This issue will almost certainly require resolution by the Supreme Court, which needs to give the issue of congressional deadlines its most thoughtful attention. [ABSTRACT FROM AUTHOR]

We characterize the optimal mortgage contract in a continuous-time setting with stochastic growth in house price and income, costly foreclosure, and a risky borrower who requires incentives to repay his debt. We show that many features of subprime loans can be consistent with properties of the optimal contract and that, when house prices decline, mortgage modification can create value for borrowers and lenders. Our model provides a number of empirical predictions that relate the features of mortgage contracts originated in a housing boom and the extent of their modification in a slump to location and borrowers' characteristics. [ABSTRACT FROM PUBLISHER]

The value of American options depends on the exercise policy followed by option holders. Market frictions, risk aversion, or a misspecified model, for example, can result in suboptimal behavior. We study the sensitivity of American options to suboptimal exercise strategies. We show that this measure is given by the Gamma of the American option at the optimal exercise boundary. More precisely, “if B is the optimal exercise price, but exercise is either brought forward when or delayed until a price B̃ has been reached, the cost of suboptimal exercise is given by ½ × Γ(B) × (B − B̃)2, where Γ(B) denotes the American option Gamma.” Therefore, the cost of suboptimal exercise is second-order in the bias of the exercise policy and depends on Gamma. This result provides new insights on American options. [ABSTRACT FROM PUBLISHER]

Motivated by the effect on valuation of stopped or reduced debt coupon payments from a company in financial distress, we value a level-dependent annuity contract where the annuity rate depends on the value of an underlying asset process. The range of possible values of this asset is divided into a finite number of regions, with constant annuity rates within each region. We present closed-form formulas for the market value of level-dependent annuities contracts when the market value of the underlying asset is assumed to follow a geometric Brownian motion. Such annuities occur naturally in models of debt with credit risk in financial economics. Our results are applied for valuing both corporate debt with suspended interest payments under the U.S. Chapter 11 provisions and loans with contractual level-dependent interest rates. [ABSTRACT FROM AUTHOR]

This paper proposes an alternative characterization of the early exercise premium that is valid for any Markovian and diffusion underlying price process as well as for any parameterization of the exercise boundary. This new representation is shown to provide the best pricing alternative available in the literature for medium- and long-term American option contracts, under the constant elasticity of variance model. Moreover, the proposed pricing methodology is also extended easily to the valuation of American options on defaultable equity and possesses appropriate asymptotic properties. [ABSTRACT FROM AUTHOR]

We test the doubly stochastic assumption under which firms' default times are correlated only as implied by the correlation of factors determining their default intensities. Using data on U.S. corporations from 1979 to 2004, this assumption is violated in the presence of contagion or “frailty” (unobservable explanatory variables that are correlated across firms). Our tests do not depend on the time-series properties of default intensities. The data do not support the joint hypothesis of well-specified default intensities and the doubly stochastic assumption. We find some evidence of default clustering exceeding that implied by the doubly stochastic model with the given intensities. [ABSTRACT FROM AUTHOR]

Although the aggregate capital share of U.S. firms has increased, capital share at the firm‐level has decreased. This divergence is due to mega‐firms that produce a larger output share without a proportionate increase in labor compensation. We develop a model in which firms insure workers against firm‐specific shocks, with more productive firms allocating more rents to shareholders, while less productive firms endogenously exit. Increasing firm‐level risk delays exit and increases the measure of mega‐firms, raising (lowering) the aggregate (average) capital share. An increase in the level of rents magnifies this effect. We present evidence that supports this mechanism. [ABSTRACT FROM AUTHOR]

Antimicrobial use contributes to the growing public health challenge of infectious diseases that are resistant to all but a few remaining treatments via natural selection. When few treatment options remain, should the last effective treatment be reserved for controlling larger outbreaks in the future? In "Dynamics of Drug Resistance: Optimal Control of an Infectious Disease," N. Chehrazi, L. E. Cipriano, and E. A. Enns formulate this important policy question as a control problem with two state variables—disease prevalence and the level of treatment resistance—for an established family of SIS infectious disease models with resistance. They prove that when the disease transmission rate is constant, it is optimal to treat everyone until the level of resistance is so high that it is no longer economical to treat anyone. Public health policies and social distancing can cause a nonconstant disease transmission rate; in these cases, it may be optimal to preserve the drug for relatively larger outbreaks or to use the drug to treat some, but not all, infected individuals. Antimicrobial resistance is a significant public health threat. In the United States alone, two million people are infected, and 23,000 die each year from antibiotic-resistant bacterial infections. In many cases, infections are resistant to all but a few remaining drugs. We examine the case in which a single drug remains and solve for the optimal treatment policy for a susceptible–infected–susceptible infectious disease model, incorporating the effects of drug resistance. The problem is formulated as an optimal control problem with two continuous state variables: the disease prevalence and drug's "quality" (the fraction of infections that are drug-susceptible). The decision maker's objective is to minimize the discounted cost of the disease to society over an infinite horizon. We provide a new generalizable solution approach that allows us to thoroughly characterize the optimal treatment policy analytically. We prove that the optimal treatment policy is a bang-bang policy with a single switching time. The action/inaction regions can be described by a single boundary that is strictly increasing when viewed as a function of drug quality, indicating that, when the disease transmission rate is constant, the policy of withholding treatment to preserve the drug for a potentially more serious future outbreak is not optimal. We show that the optimal value function and/or its derivatives are neither C1 nor Lipschitz continuous, suggesting that numerical approaches to this family of dynamic infectious disease models may not be computationally stable. Furthermore, we demonstrate that relaxing the standard assumption of a constant disease transmission rate can fundamentally change the shape of the action region, add a singular arc to the optimal control, and make preserving the drug for a serious outbreak optimal. In addition, we apply our framework to the case of antibiotic-resistant gonorrhea. [ABSTRACT FROM AUTHOR]

We study whether default options are mispriced in equity values by employing a structural equity valuation model that explicitly takes into account the value of the option to default (or abandon the firm) and uses firm‐specific inputs. We implement our model on the entire cross section of stocks and identify both over‐ and underpriced equities. An investment strategy that buys undervalued stocks and shorts overvalued stocks generates an annual four‐factor alpha of about 11% for U.S. stocks. The model's performance is stronger for stocks with a higher value of the default option, such as distressed or highly volatile stocks. [ABSTRACT FROM AUTHOR]

This paper analyses the impact of parametric timing portfolio strategies on the U.S. stock market. In particular, we assume that the log-returns follow a given parametric Lévy process and we describe a methodology to approximate the distributions of stopping times using the underlying Markov transition matrix. Therefore, we propose the use of portfolio strategies based on the maximization of the ratio between the expected first passage time to reach a low level of wealth and the expected first passage time to reach a high level of wealth. Finally, we compare the ex-post wealth obtained maximizing the ratio of proper expected stopping times under different distributional assumptions. [ABSTRACT FROM AUTHOR]

The article presents an edited transcript of a speech that Northwestern University School of Law Professor John O. McGinnis delivered at the Federalist Society for Law & Public Policy Studies' Student Symposium at Georgetown University, and it mentions his views about the originalism constitutional interpretation principle. The original meaning of the U.S. Constitution and the constitutional amendment process under Article V of America's Constitution are assessed.

Sender, who is either good or bad, wishes to look good at an exogenous deadline. Sender privately observes if and when she can release a public flow of information about her private type. Releasing information earlier exposes to greater scrutiny, but signals credibility. In equilibrium bad Sender releases information later than good Sender. We find empirical support for the dynamic predictions of our model using data on the timing of U.S. presidential scandals and U.S. initial public offerings. In the context of elections, our results suggest that October Surprises are driven by the strategic behaviour of bad Sender. [ABSTRACT FROM AUTHOR]

In this paper we consider the pricing of American options, governed by a partial differential complementarity problem. The differential problem is first approximated by a semi-linear PDE using two distinct penalty approaches which are well known in computational finance. We then initiate the two-grid algorithm by solving the nonlinear problem on a coarse grid and further the linearized in the interpolated coarse-grid solution problem on a fine grid. By means of the maximum principle the algorithm is shown to be of fourth order convergence rate in space. Numerical experiments verify the presented two-grid approach where we draw some interesting conclusions. [ABSTRACT FROM AUTHOR]

This study describes three types of digital wage theft, as depicted in 330 cases litigated in federal and state court. The first, known as “rounding,” occurs when employers set their timekeeping software to alter employee punch time in a preset increment (typically moving punches to the nearest quarter hour). The second, “automatic break deductions,” involves subtracting a preset increment of time (usually thirty minutes) from employee hours to reflect their scheduled meal break, regardless of whether the break is taken. Both such practices occupy a legal gray zone under the Fair Labor Standards Act (FLSA). The third, known as “time shaving,” occurs when supervisors alter employee time records to reduce recorded hours. Although more clearly prohibited under existing rules, time shaving cases can be difficult to certify as collective actions beyond a single worksite. Plaintiffs seeking to recover lost wages in these cases face highly uncertain prospects in litigation. Outcomes depend on complex questions of fact and unpredictable judicial rulings that turn on implied notions of fairness. Even in successful cases, employers keep most of the lost wages because damages are only awarded to the small fraction of employees who opted in to the litigation. In sum, this article illustrates how federal rules fail to deter employers from adopting these practices. It concludes by recommending several changes to federal law. [ABSTRACT FROM AUTHOR]

As tourism and visitation increases to parks and protected areas worldwide, concerns regarding degradation of natural resources and visitor experiences also increase. As such, understanding visitor use patterns and spatial characteristics is important for better management of social and ecological resources. In many parks and protected areas, transportation systems (including park roads, parking lots, personal vehicles, public transit services, bicycle and/or pedestrian paths, and Intelligent Transportation Systems (ITS) that help deliver visitors to their destinations within parks) are a primary way for tourists and visitors to interact with and experience natural environments. Transportation systems designed with visitor use patterns in mind can both provide a positive experience for tourists as well as minimize impacts to natural resources within parks and protected areas. Our research used Global Positioning System (GPS)-based technology and a statistical classification procedure to examine spatial and temporal patterns of vehicular visitation in the Moose-Wilson corridor of Grand Teton National Park. While GPS-based technology has been used in parks and protected areas to study the spatial behavior of hikers and bikers, it has not been widely utilized to study the spatial behavior patterns of visitors travelling in vehicles to park destinations. Similarly, statistical classifications have been used to understand visitor behavior patterns in parks and protected areas, but are rarely applied to spatial data such as GPS tracks of visitor spatial movements. This classification based on spatial behavior resulted in the categorization of visitors into three types: Opportunistic Commuters, Wildlife/Scenery Viewers, and Hikers. These results expand existing literature suggesting that interpretable patterns of visitor spatial movements can result from classification studies using GPS-based collection of visitor behavior data. Understanding these patterns of visitor behavior is important for the management of social and natural resource conditions at park destinations as well as visitor experiences within the transportation corridor, as different types of visitors often exhibit different spatial behavior patterns. The classification and associated patterns of visitor behavior have important implications for managers of parks and protected area as different types of visitors may require different transportation and information needs in order to achieve their desired experience and minimize ecological impacts. [ABSTRACT FROM AUTHOR]

This paper examines the hypothesis that, during merger waves, a bidder's actions provide information for other bidders and the market. I develop a real options model to explore the interplay between acquisition timing and the market reaction to these events. The model predicts a pattern of declining announcement returns along the merger wave and various forms of contagion returns. Consistent with the model's predictions, in a sample of U.S. mergers, I find that the dispersion in bidders' post-acquisition performance declines along the merger wave and that the start of a merger wave is associated with an increase in the conditional correlation of a bidder's stock returns and the stock returns of other bidders. [ABSTRACT FROM AUTHOR]

Composite materials are already being used in the mass production of structural components in the automotive industry, particularly at the BMW Group. Adhesive bonding is generally considered to be the best technique for joining CFRP (carbon fiber reinforced plastic) light-weight structures. The conventional NDT (nondestructive testing) methods currently being used focus on the detection of material defects, e.g. debonding. These methods give little information about the surface properties or bond quality. A new ENDT (extended nondestructive testing) method is the BonNDTinspect system, based on a patent held by the Fraunhofer IFAM. An ultrasonic atomizer nozzle creates a water-aerosol and the small water droplets are sprayed onto the surface. Depending on the surface properties (surface energy or contamination state), the aerosol will form wide or narrow drops on the surface. We determined a test for certain contaminations, including release agents, oil, and fingerprints, the detection of which is critical to ensure the performance of adhesively joined CFRP structures. The BonNDTinspect system is an inline-capable NDT technique that is suitable for distinguishing surface states for adhesive bonding of CFRP. We verify this statement with destructive tests, including the single-lap shear test. It was found by using an extension of the evaluation criteria that it is possible to detect contamination such as water-soluble release agent, CFRP dust and fingerprints. The investigated contamination with hydraulic oil allows only a clear differentiation between cleaned and contaminated. A contamination with corundum is not detectable by the BonNDTinspect system alone. [ABSTRACT FROM AUTHOR]

Objective: Bicycling is an affordable way to increase access to employment, schooling, and services and an effective measure against obesity. Bikeshare programs can make bicycling accessible to diverse populations, but little evidence exists on their adoption in low-resource neighborhoods. Our study examined factors associated with bikeshare use in a metropolitan area in the southern United States.Methods: We performed a retrospective cross-sectional analysis of a database of clients (N=815) who rented a bicycle from Zyp Bikeshare in Birmingham, Alabama between October 2015 and November 2016. Individual-level variables included bike use frequency, average speed, total miles traveled, total minutes ridden, bike type (traditional vs electricity-assisted pedelec), membership type, sex, and age. Area-level data aggregated to Census tracts, proxies for neighborhoods, were obtained from the 2010 US Census after geocoding clients' billing addresses. Using exploratory factor analysis, a neighborhood socioeconomic disadvantage index (SDI) was constructed. Bikeshare station presence in a tract was included as a covariate. Multivariate linear regression models, adjusted for clustering on Census tracts, were estimated to determine predictors of bikeshare use.Results: In a multivariate regression model of individual and neighborhood characteristics adjusted for clustering, each decile increase in the SDI was associated with a 9% increase in bikeshare use (P<.001). Bikeshare use was also positively associated with speed (.1, P<.001), total miles (.008, P<.001), and pedelec use (1.02, P<.01).Conclusion: Higher neighborhood socioeconomic disadvantage is associated with higher bikeshare use. Bikeshare is a viable transportation option in low-resource neighborhoods and may be an effective tool to improve the connectivity, livability, and health of urban communities. [ABSTRACT FROM AUTHOR]

This article introduces and analyzes a Walrasian model of worker flows, job flows, vacancies, and unemployment. Calibrating the model to U.S. data, the article finds that all variables comove with output quite well but that they fluctuate too little. However, the failure is not as bad as in 'Shimer's puzzle.' Interestingly, the article also finds that introducing establishment dynamics into the model, while realistic, is irrelevant for understanding unemployment and vacancy fluctuations: The business cycles of the model with establishment dynamics are virtually the same as those of a version with a representative firm. [ABSTRACT FROM AUTHOR]

We study the profit-maximizing price path of a monopolist selling a durable good to buyers who arrive over time and whose values for the good evolve stochastically. The setting is completely stationary with an infinite horizon. Contrary to the case with constant values, optimal prices fluctuate with time. We argue that consumers' randomly changing values offer an explanation for temporary price reductions that are often observed in practice. (JEL D82) [ABSTRACT FROM AUTHOR]

Rescue activities in US acute care settings reaffirm an unspoken belief in an unlimited future for patients, families, clniicians, and the public at large. Reaching for that future erases the patient's experiences in the present, which can be detrimental to her welfare. A case study is used to illustrate how clinicians' urgency to reify their faith in the patient's unlimited future violated her real-world existence. [ABSTRACT FROM AUTHOR]

This paper empirically studies firm's strategic exit decisions in an environment where demand is declining. Specifically, I quantify the extent to which the exit process generated by firms' strategic interactions deviates from the outcome that maximizes industry profits. I develop and estimate a dynamic exit game using data from the US movie theater industry in the 1950s, when the industry faced demand declines. Using the estimated model, I quantify the magnitude of strategic delays and find that strategic interactions cause an average delay of exit of 2.7 years. I calculate the relative importance of several components of these strategic delays. (JEL D92, L11, L82, N72) [ABSTRACT FROM AUTHOR]

Over time, there have been considerable changes in the variety, availability, production, distribution, and use and user(s) of psychoactive substances, the meaning of substance use and its impact on users and their social or physical environment(s). This article reviews the mechanisms of introduction of psychoactive substances such as alcohol, tobacco, coffee, tea and cannabis to populations and communities that did not have them before. It considers the historical tension between early adopters who greet new substances with various levels of enthusiasm in their eagerness to enjoy what they believe to be the benefits of using these substances, and those focused on what they believe to be the negative aspects of use, who decry these new substances with horror. With more nonusers than users in the population, social policies tend to be directed at preventing, restricting, or punishing selected use, users and .drugs., using controls and interventions such regulation, incarceration, death sentence, treatment, prevention, legalization, taxation, among others. Whatever their intent or wished-for impact, all had consequences that produced additional, unplanned for, and (often) negative effects. This paper will consider some of these sequences as they occurred historically with other substances in light of the current shift to legalization and normalization of cannabis, noting the mechanisms of use, controls, and consequences of some types of formal interventions and give some attention to how and what we can learn from our experiences in order to plan ahead and become better prepared to successfully deal with the ‘unexpecteds’ of that well-known ‘hell’ paved with good intentions. [ABSTRACT FROM PUBLISHER]

The recent U.S. house price bubble and the subsequent deep financial crisis have renewed the interest in reliable identification methods for asset price bubbles. While there is a growing number of studies focussing on the detection of U.S. regional bubbles, estimations of the likely starting points in different local U.S. markets are still rare. Using regional data from 1990 to 2010 methods of Statistical Process Control (SPC) are used to test for house price bubbles in 17 major U.S. cities. Based on the EWMA control chart we also present estimations of the likely starting point of the regional bubbles. As a result, we find indications of house price bubbles in all 17 considered cities. Interestingly enough, the recent bubble was not a homogeneous event since regional starting points range from 1996 to 2002. [ABSTRACT FROM AUTHOR]

We consider the optimal exercise of a portfolio of American call options in an incomplete market. Options are written on a single underlying asset but may have different characteristics of strikes, maturities, and vesting dates. Our motivation is to model the decision faced by an employee who is granted options periodically on the stock of her company, and who is not permitted to trade this stock. The first part of our study considers the optimal exercise of single options. We prove results under minimal assumptions and give several counterexamples where these assumptions fail-describing the shape and nesting properties of the exercise regions. The second part of the study considers portfolios of options with differing characteristics. The main result is that options with comonotonic strike, maturity, and vesting date should be exercised in order of increasing strike. It is true under weak assumptions on preferences and requires no assumptions on prices. Potentially the exercise ordering result can significantly reduce the complexity of computations in a particular example. This is illustrated by solving the resulting dynamic programming problem in a constant absolute risk aversion utility indifference model. [ABSTRACT FROM AUTHOR]

This research proposes a new non-parametric approach to pairs trading based on renko and kagi constructions which originated from Japanese charting indicators and were introduced to academic studies by Pastukhov. The method exploits statistical information about the variability of the tradable process. The approach does not find a long-run mean of the process and trade towards it like other methods of pairs trading. The only assumption we need is that the statistical properties of the spread process volatility remain reasonably constant. The theoretical profitability of the method has been demonstrated for the Ornstein–Uhlenbeck process. Tests on the daily market data of American and Australian stock exchanges show statistically significant average excess returns ranging from 1.4 to 3.6% per month and annualized Sharpe ratio from 1.5 to 3.4. [ABSTRACT FROM AUTHOR]

The present article deals with the performance of the American avangard theater Nature Theater of Oklahoma, looking at the texts created with a documentary technique, documenting a special function of memory, or rather oblivion. Cultural oblivion is a key for interpreting the texts of this group. [ABSTRACT FROM AUTHOR]

The Food and Drug Administration (FDA) guidance for evaluating cardiovascular (CV) risk in new antidiabetic therapies to treat type 2 diabetes released in December 2008 recommends that sponsors conduct appropriate data analysis to rule out CV safety concerns for drugs treating type 2 diabetes. CV trials of antidiabetic drugs and drugs of other indications for chronic conditions are usually large-scale/long-term trials and can be designed as adaptive noninferiority/superiority trials. In these trials, treatment effect may not manifest immediately after patients take study medication and there will be a dilution in treatment effect after treatment discontinuation. These factors should be taken into account for more precise planning of study sample size and timeline. In this paper, we first derive closed-form formulas for the number of events and total exposure as functions of many other trial parameters. We then outline some considerations for the design of an adaptive noninferiority/superiority CV trial based on ideas of other authors. We also use an example to illustrate the application of the methods. [ABSTRACT FROM AUTHOR]

This paper considers the problem of pricing options with early-exercise features whose pay-off depends on several sources of uncertainty. We propose a stochastic grid method for estimating the optimal exercise policy and use this policy to obtain a low-biased estimator for high-dimensional Bermudan options. The method has elements of the least-squares method (LSM) of Longstaff and Schwartz [Valuing American options by simulation: A simple least-squares approach, Rev. Finan. Stud. 3 (2001), pp. 113–147], the stochastic mesh method of Broadie and Glasserman [A stochastic mesh method for pricing high-dimensional American option, J. Comput. Finance 7 (2004), pp. 35–72], and stratified state aggregation along the pay-off method of Barraquand and Martineau [Numerical valuation of high-dimensional multivariate American securities, J. Financ. Quant. Anal. 30 (1995), pp. 383–405], with certain distinct advantages over the existing methods. We focus on the numerical results for high-dimensional problems such as max option and arithmetic basket option on several assets, with basic error analysis for a general one-dimensional problem. [ABSTRACT FROM PUBLISHER]