cssi/SciSciGPT-SciSciNet huggingface dataset:
Housing Market Dynamics: Disequilibrium, Mortgage Default, and Reverse Mortgages

The mortgage market collapse which followed the burst of the housing bubble in 2007 led to unprecedented levels of mortgage default, mortgage foreclosure, and housing vacancies. The dramatic increase in mortgage terminations prompted extensive discussions among academics, industry practitioners, regulators, and policymakers. These discussions included such issues as the underlying causes of the mortgage market collapse and the impact of declining house prices on mortgage default and foreclosure. This special issue results from the 2013 FSU-UF Critical Issues Symposium entitled “Housing Market Issues: Initiatives, Policies and the Economy” where the impact of the recent market collapse was examined on topics such as the negative spillover effect of foreclosure, the determinants of mortgage default and prepayment, disequilibrium models of the housing market, and the growth of the reverse mortgage market. This introductory paper serves to set the stage by relating the papers in this special issue to the previous literature. It provides both a clear picture of the state of knowledge in these critical areas and the significant contributions of these recent studies.
The downside of good peers: how classroom composition differentially affects men's and women's STEM persistence

Abstract This paper investigates whether class composition can help explain why women are disproportionately more likely to fall out of the “STEM” pipeline. Identification comes from a standardized enrollment process at a large public university that essentially randomly assigns freshmen to different mandatory introductory chemistry lectures. Using administrative data, I find that women who are enrolled in a class with higher ability peers are less likely to graduate with a STEM degree, while men's STEM persistence is unaffected. The effect is largest for women in the bottom third of the ability distribution. I rule out that this is driven solely by grades.
Adoption of Information Technology in Small Business: Testing Drivers of Adoption for Entrepreneurs

This study reports on how small retailers are adopting IT for their entrepreneurial venture. Three antecedents are posited to influence the information technology adoption in small business environ...
Pedestrian motion direction estimation using simulated automotive MIMO radar

Micro-Doppler (MD)-based target classification capabilities of automotive radars can provide high reliability and short latency to future active safety automotive features. A large number of pedestrians surrounding a vehicle in practical urban scenarios mandate prioritization of their treatment level. Distinguishing between relevant pedestrians that are crossing the street or are within the vehicle path and those that are on the sidewalks and are moving along the vehicle route can significantly minimize the number of vehicle-to-pedestrian accidents. This work proposes a novel technique for estimating a pedestrian direction of motion that treats pedestrians as complex distributed targets and utilizes their MD radar signatures. The MD signatures are shown to be indicative of pedestrian direction of motion, and a supervised regression is used to estimate the mapping between the directions of motion and the corresponding MD signatures. In order to achieve higher regression performance, a state-of-the-art sparse dictionary learning-based feature extraction algorithm was adopted from the field of computer vision by drawing a parallel between the Doppler effect and the video temporal gradient. The performance of the proposed approach is evaluated in practical automotive scenario simulations, where a walking pedestrian is observed by a multiple-input/multiple-output automotive radar with a two-dimensional rectangular array. The simulated data was generated using the statistical Boulic-Thalman human locomotion model. Accurate direction of motion estimation was achieved by using support vector regression and multilayer perceptron-based regression algorithms. The results show that the direction estimation error is less than 10° in 95% of the tested cases for pedestrian at a range of 100 m from the radar.
Role of distribution automation in restoration of distribution systems after emergencies

Remote-controlled sectionalizers provide a simple and cost-effective way to automate distribution systems. These sectionalizers speed up isolation of faulted sections and restoration of unfaulted sections through alternate routes. They are also useful for step-by-step restoration of distribution systems following extended outages. The main focus of this presentation is to show that the order of switching has a significant influence on the total time needed to restore the system without violating the loading limits of the substation transformer. Future issues crucial for advancement of this research are also identified.
Radiation Induced Fractures of Sacrum: CT Diagnosis

Sacral insufficiency fracture due to bone atrophy may develop as a complication of irradiation of pelvic malignancies. Pain is the presenting symptom and the clinical diagnoses most often considered are recurrence of the original malignancy and metastatic disease. Computed tomography provides the most specific information helpful for the detection of these fractures and for exclusion of recurrent malignancy.
Synthesis, Characterization, and Properties of Metal Phosphide Catalysts for the Hydrogen-Evolution Reaction

Hydrogen gas obtained by the electrolysis of water has long been proposed as a clean and sustainable alternative to fossil fuels. Noble metals such as Pt are capable of splitting water at low overpotentials, but the implementation of inexpensive solar-driven water-splitting systems and electrolyzers could benefit from the development of robust, efficient, and abundant alternatives to noble metal catalysts. Transition metal phosphides (MxPy) have recently been identified as a promising family of Earth abundant electrocatalysts for the hydrogen-evolution reaction (HER) and are capable of operating with low overpotentials at operationally relevant current densities while exhibiting stability under strongly acidic conditions. In this review, we highlight the progress that has been made in this field and provide insights into the synthesis, characterization, and electrochemical behavior of transition metal phosphides as HER electrocatalysts. We also discuss strategies for the incorporation of metal phosphides ...
Crystal structure of BaMnB2O5 containing structurally isolated manganese oxide sheets.

In an attempt to search for mixed alkaline-earth and transition metal pyroborates, the title compound, barium manganese(II) pyroborate, has been synthesized by employing a flux method. The structure of BaMnB2O5 is composed of MnO5 square pyramids that form Mn2O8 dimers by edge-sharing and of pyroborate units ([B2O5]4−) that are composed of two corner-sharing trigonal–planar BO3 units. These building blocks share corners to form ∞2[MnB2O5]2− layers extending parallel to (100). The Ba2+ cations reside in the gap between two manganese pyroborate slabs with a coordination number of nine. The title compound forms an inter­esting spiral framework propagating along the 21 screw axis. The structure is characterized by two alternating layers, which is relatively rare among known transition-metal-based pyroborate compounds.
Perceived Injustice Is Associated With Pain and Functional Outcomes in Children and Adolescents With Chronic Pain: A Preliminary Examination

Abstract Chronic pain is prevalent in children/adolescents and contributes to high rates of healthcare utilization. Research suggests injustice perceptions about pain are important in adult patients and a possible treatment focus. We conducted a preliminary evaluation of the psychometric properties of the Injustice Experiences Questionnaire (IEQ) and the relationship between injustice perceptions, pain, and functioning in chronic pain patients (N = 139, mean age = 15 years, 72% female) presenting to a pediatric pain clinic. Patients completed measures assessing pain intensity, injustice perceptions about pain, catastrophizing, overall functional disability, emotional functioning, social functioning, and school functioning. The IEQ showed good reliability and validity. Higher levels of perceived injustice were associated with higher levels of pain intensity, catastrophizing, and functional disability, and with poorer emotional, social, and school functioning. Additionally, perceived injustice remained significantly associated with pain intensity, functional disability, emotional functioning, social functioning, and school functioning after accounting for relevant demographic and clinical factors. This is the first study to suggest that injustice perceptions are important in the experience of pediatric chronic pain patients. Future studies should more thoroughly examine the psychometric properties of the IEQ in children/adolescents and elucidate the causal nature of these relationships, which will inform treatment efforts to improve pediatric pain care. Perspective This initial investigation suggests that injustice perceptions about pain can be reliably and validly measured and are tied to important clinical outcomes in children/adolescents. Future studies that replicate and extend these preliminary results are necessary to determine the extent to which injustice perceptions are an important target for intervention.
Market Power in International Commodity Trade: The Case of Coffee

This paper studies the impact of market power on international commodity prices. I use a standard oligopoly model and exploit historical variations in the structure of the international coffee bean market to assess the impact of a cartel treaty on coffee prices and its global welfare consequences. The results suggest that the International Coffee Agreement (ICA, 1965–89) raised its price by 75% above the Cournot-competitive level, annually transferring approximately $12 billion from consumers to exporting countries, and its lapse in 1989 explains four-fifths of the subsequent price decline, that is, the ‘coffee crisis.’
Risk of Pavement Fracture due to Eigenstresses at Early Ages and Beyond

AbstractTensile cracks significantly affect the durability of concrete pavements, leading to an increase in the costs of maintenance and rehabilitation. A model is developed that relates thermal, chemical, and hygral evolutions at small scales due to different distress mechanisms to the risk of fracture at the structural scale. The method is based on application of linear elastic fracture mechanics (LEFM) to eigenstresses that develop in infinite- and finite-length beams on an elastic foundation that represents the subgrade. Axial and bending contributions to the energy release rate are determined for a worst-case scenario of an entirely cracked pavement section in functions of material properties, structural dimensions, and eigenstress forces and moments. By way of example, the model is used to study the risk of fracture of concrete pavements due to two different mechanisms: (1) autogeneous shrinkage at early ages of placing the concrete and (2) thermal cycles at the short term and long term after a temp...
Efficiency and Budget Balance

We study efficiency and budget balance for designing mechanisms in general quasi-linear domains. Green and Laffonti¾?[13] proved that one cannot generically achieve both. We consider strategyproof budget-balanced mechanisms that are approximately efficient. For deterministic mechanisms, we show that a strategyproof and budget-balanced mechanism must have a sink agent whose valuation function is ignored in selecting an alternative, and she is compensated with the payments made by the other agents. We assume the valuations of the agents come from a bounded open interval. This result strengthens Green and Laffont's impossibility result by showing that even in a restricted domain of valuations, there does not exist a mechanism that is strategyproof, budget balanced, and takes every agent's valuation into consideration--a corollary of which is that it cannot be efficient. Using this result, we find a tight lower bound on the inefficiencies of strategyproof, budget-balanced mechanisms in this domain. The bound shows that the inefficiency asymptotically disappears when the number of agents is large--a result close in spirit to Green and Laffonti¾?[13, Theorem 9.4]. However, our results provide worst-case bounds and the best possible rate of convergence. Next, we consider minimizing any convex combination of inefficiency and budget imbalance. We show that if the valuations are unrestricted, no deterministic mechanism can do asymptotically better than minimizing inefficiency alone. Finally, we investigate randomized mechanisms and provide improved lower bounds on expected inefficiency. We give a tight lower bound for an interesting class of strategyproof, budget-balanced, randomized mechanisms. We also use an optimization-based approach--in the spirit of automated mechanism design--to provide a lower bound on the minimum achievable inefficiency of any randomized mechanism. Experiments with real data from two applications show that the inefficiency for a simple randomized mechanism is 5---100 times smaller than the worst case. This relative difference increases with the number ofi¾?agents.
Plate Boundary Observatory and related networks: GPS data analysis methods and geodetic products

The Geodesy Advancing Geosciences and EarthScope (GAGE) Facility Global Positioning System (GPS) Data Analysis Centers produce position times series, velocities and other parameters for approximately two thousand continuously operating GPS receivers spanning a quadrant of Earth's surface encompassing the high Arctic, North America and Caribbean. The purpose of this review is to document the methodology for generating station positions and their evolution over time, and to describe the requisite tradeoffs involved with combination of results. GAGE GPS analysis involves formal merging within a Kalman filter of two independent, loosely-constrained solutions: one is based on precise point positioning produced with the GPS Inferred Positioning System, Orbit Analysis Simulation (GIPSY/OASIS) software at Central Washington University (CWU) and the other is a network solution based on phase and range double-differencing produced with the GPS at MIT (GAMIT) software at New Mexico Institute of Mining and Technology (NMT). The primary products generated are the position time series that show motions relative to a North America reference frame and secular motions of the stations represented in the velocity field. The position time series themselves contain a multitude of signals in addition to the secular motions. Co-seismic and post-seismic signals, seasonal signals from hydrology, and transient events, some understood and other not yet fully explained, are all evident in the time series and ready for further analysis and interpretation. We explore the impact of analysis assumptions on the reference frame realization and on the final solutions, and we compare within the GAGE solutions and with others.
Accommodation of penetrative strain during deformation above a ductile décollement

The accommodation of shortening by penetrative strain is widely considered as an important process during contraction, but the distribution and magnitude of penetrative strain in a contractional system with a ductile decollement are not well understood. Penetrative strain constitutes the proportion of the total shortening across an orogen that is not accommodated by the development of macroscale structures, such as folds and thrusts. In order to create a framework for understanding penetrative strain in a brittle system above a ductile decollement, eight analog models, each with the same initial configuration, were shortened to different amounts in a deformation apparatus. Models consisted of a silicon polymer base layer overlain by three fine-grained sand layers. A grid was imprinted on the surface to track penetrative strain during shortening. As the model was shortened, a series of box fold structures developed, with a zone of penetrative strain in the foreland. Penetrative strain in the foreland decreases away from the fold belt. Restoration of the model layers to the horizontal indicates that penetrative strain accounts for 90.5%–30.8% of total shortening in a brittle system with a ductile decollement, compared to 45.2%–3.6% within a totally brittle system. Analog model geometries were consistent with the deformation styles observed in salt-floored systems, such as the Swiss Jura. Penetrative strain has not been accounted for in previous studies of salt-floored regions and estimates of this type could help resolve concerns of missing shortening highlighted by global positioning system data.
Quantitative quasisymmetric uniformization of compact surfaces

Bonk and Kleiner showed that any metric sphere which is Ahlfors 2-regular and linearly locally contractible is quasisymmetrically equivalent to the standard sphere in a quantitative way. We extend this result to arbitrary metric compact orientable surfaces.
Performance robustness of discrete-time systems with structured uncertainty

Given an interconnection of a nominal discrete-time plant and a stabilizing controller together with structured, norm-bounded, nonlinear/time-varying perturbations, necessary and sufficient conditions for robust stability and performance of the system are provided. It is shown that performance robustness is equivalent to stability robustness in the sense that both problems can be dealt with in the framework of a general stability robustness problem. The resulting stability robustness problem is shown to be equivalent to a simple algebraic one, the solution of which provides the desired necessary and sufficient conditions for performance/stability robustness. These conditions provide an effective tool for robustness analysis and can be applied to a large class of problems. In particular, it is shown that some known results can be obtained immediately as special cases of these conditions. >
Overview of Steam Generator Tube Degradation and Integrity Issues

The degradation of steam generator tubes in pressurized water nuclear reactors, and, in particular, the stress corrosion cracking (SCC) of Alloy 600 tubes, continues to be a serious problem. Primary water SCC is commonly observed at the roll transition zone (RTZ), at U-bends and tube denting locations, and occasionally in plugs and sleeves. Outer-diameter SCC (ODSCC) and intergranular attack (IGA) commonly occur near tube support plate (TSP) crevices, near the tube sheet in crevices, or under sludge piles, and occasionally in the free span. A particularly troubling recent trend has been the increasing occurrence of axial and circumferential cracking at the RTZ on both the primary and secondary sides. Outer-diameter stress corrosion cracking in TSP crevices, commonly consisting of segmented axial cracks with interspersed uncracked ligaments, is also becoming more common. Despite recent advances in inservice inspection (ISI) technology, a clear need still exists for quantifying and improving the reliability of ISI methods with respect to the probability of detection of the various types of flaws and their accurate sizing. These improvements are necessary to permit an accurate assessment of the consequences of leaving degraded tubes in service over the next reactor operating cycle. Degradation modes such as circumferential cracking, intergranular attack, and ODSCC at the TSP have affected a large number of tubes. New regulatory guidance is being developed that requires the development and implementation of a steam generator management program that monitors tube condition against accepted performance criteria to ensure that the tubes will perform the required safety function over the next operating cycle. In formulating new guidance for the implementation of alternate repair criteria, the U.S. Nuclear Regulatory Commission is also evaluating the contribution to overall plant risk from severe accidents. Preliminary analyses are being performed for a postulated severe-accident scenario that involves station blackout and loss of primary feedwater, in order to determine the probability of failure for degraded tubes.
Sparse Control for Dynamic Movement Primitives

Abstract This paper describes the use of spatially-sparse inputs to influence global changes in the behavior of Dynamic Movement Primitives (DMPs). The dynamics of DMPs are analyzed through the framework of contraction theory as networked hierarchies of contracting or transversely contracting systems. Within this framework, sparsely-inhibited rhythmic DMPs (SI-RDMPs) are introduced to both inhibit or enable rhythmic primitives through spatially-sparse modification of the DMP dynamics. SI-RDMPs are demonstrated in experiments to manage start-stop transitions for walking experiments with the MIT Cheetah. New analytical results on the coupling of oscillators with diverse natural frequencies are also discussed.
A mixed-field type of Vidicon

A new type of Vidicon has been developed which uses magnetic focus and electrostatic deflection. Since both fields are superimposed in the same space, Focus Projection and Scanning (FPS) is accomplished simultaneously. In this way, Vidicon tubes of very compact size can be realized (typically a format of 1 inch by 4½ inches overall). The electron optics of this FPS system is outlined. It is demagnifying and yields excellent landing and edge-focus performance. Signal output is high (0.5 µA), and resolution in excess of 800 TV lines has been realized in a 1-inch envelope with 350 volts as the highest voltage. For a tube of given size, various performance factors such as resolution, shading, and deflection sensitivity can be balanced by design such as to enhance some factors at the expense of others. This mutual interdependence is briefly discussed. It is also shown that the ceiling of performance for this combination of crossed fields is inherently higher than for similar devices using sequential, rather than simultaneous, focusing and deflection.
Directional radiative characteristics of conical cavities and their relation to lunar phenomena

Directional absorptivity characteristics of conical cavities and use as thermal model for lunar meteor craters
The blessing and the curse of the multiplicative updates

Multiplicative updates multiply the parameters by nonnegative factors. These updates are motivated by a Maximum Entropy Principle and they are prevalent in evolutionary processes where the parameters are for example concentrations of species and the factors are survival rates. The simplest such update is Bayes rule and we give an in vitro selection algorithm for RNA strands that implements this rule in the test tube where each RNA strand represents a different model. In one liter of the RNA "soup" there are approximately 1020 different strands and therefore this is a rather high-dimensional implementation of Bayes rule. We investigate multiplicative updates for the purpose of learning online while processing a stream of examples. The "blessing" of these updates is that they learn very fast because the good parameters grow exponentially. However their "curse" is that they learn too fast and wipe out parameters too quickly.We describe a number of methods developed in the realm of online learning that ameliorate the curse of these updates. The methods make the algorithm robust against data that changes over time and prevent the currently good parameters from taking over. We also discuss how the curse is circumvented by nature. Some of nature's methods parallel the ones developed in Machine Learning, but nature also has some additional tricks.
Soft Information in Loan Agreements

In this study, we seek to understand whether soft information conveyed by contracting language found in private loan agreements is informative regarding borrower risk. We proxy for credit-risk-rele...
PATELLAR RESURFACING: RARELY IF EVER NECESSARY – OPPOSES

The decision to resurface the patella has been well studied. While regional differences exist, the overwhelming choice by most surgeons in the United States is to resurface the patella. Data supports that this is the correct choice. Articular cartilage on metal has not been shown to be a good long term bearing surface. Cushner et al has also shown that cartilage in the arthritic knee has significant pathologic abnormalities. Patella surfacing has excellent long-term results with a low complication rate. Anterior knee pain is a common complaint after knee replacement and is even more common in TKA with unresurfaced patella. Pakos et al had more reoperations and greater anterior knee pain when the patella was NOT resurfaced. Parvizi et al also found less patient satisfaction with unresurfaced patellas. Meta-analysis results indicate higher revision rates with unresurfaced patellas. Bilateral knee studies also favor resurfaced patella. Higher revision rates were also confirmed in the Swedish Registry with a 140% higher revision rate in TKA with unresurfaced patellas. In addition second operations to resurface the patella often are unsuccessful at alleviating pain. Surgeons who choose not to resurface the patella must accept that their patients will have the same or greater degree of anterior knee pain and a significantly greater risk for reoperation.
The Learning Curve in Endoscopic Endonasal Resection of Craniopharyngiomas

OBJECTIVE There is a paucity of literature regarding the learning curve associated with performing endoscopic endonasal cranial base surgery. The purpose of this study was to determine to what extent a learning curve might exist for endoscopic endonasal resection in cases of craniopharyngiomas. METHODS A retrospective review was performed for all endoscopic endonasal craniopharyngioma resections performed at Thomas Jefferson University from 2005 to 2015. To assess for a learning curve effect, patients were divided into an early cohort (2005-2009, n = 20) and a late cohort (2010-2015, n = 23). Preoperative demographics, clinical presentation, imaging characteristics, extent of resection, complications, tumor control, and visual and endocrine outcomes were obtained. Categorical variables and continuous variables were compared using a 2-sided Fisher's exact test and t-test, respectively. RESULTS Only the index operation performed at the authors' institution was included. There were no statistically significant differences between early and late cohorts in terms of patient age, sex, presenting symptoms, history of surgical or radiation treatment, tumor size or consistency, hypothalamic involvement, or histological subtype. The rate of gross-total resection (GTR) increased over time from 20% to 65% (p = 0.005), and the rate of subtotal resection decreased over time from 40% to 13% (p = 0.078). Major neurological complications, including new hydrocephalus, meningitis, carotid artery injury, or stroke, occurred in 6 patients (15%) (8 complications) in the early cohort compared with only 1 (4%) in the late cohort (p = 0.037). CSF leak decreased from 40% to 4% (p = 0.007). Discharge to home increased from 64% to 95% (p = 0.024). Visual improvement was high in both cohorts (88% [early cohort] and 81% [late cohort]). Rate of postoperative panhypopituitarism and permanent diabetes insipidus both increased from 50% to 91% (p = 0.005) and 32% to 78% (p = 0.004), which correlated with a significant increase in intentional stalk sacrifice in the late cohort (from 0% to 70%, p < 0.001). CONCLUSIONS High rates of near- or total resection and visual improvement can be achieved using an endoscopic endonasal approach for craniopharyngiomas. However, the authors did find evidence for a learning curve. After 20 cases, they found a significant decrease in major neurological complications and significant increases in the rates of GTR rate and discharge to home. Although there was a large decrease in the rate of postoperative CSF leak over time, this was largely attributable to the inclusion of very early cases prior to the routine use of vascularized nasoseptal flaps. There was a significant increase in new panhypopituitarism and diabetes insipidus, which is attributable to increase rates of intentional stalk sacrifice.
Zero modes in the light-front coupled-cluster method

The light-front coupled-cluster (LFCC) method is a technique for solving Hamiltonian eigenvalue problems in light-front-quantized field theories. Its primary purpose is to provide a systematic sequence of solvable approximations to the original eigenvalue problem without the truncation of Fock space. Here we discuss the incorporation of zero modes, modes of zero longitudinal momentum, into the formalism of the method. Without zero modes, the light-front vacuum is trivial, and the vacuum expectation value of the field is always zero. The LFCC method with zero modes provides for vacuum structure, in the form of a generalized coherent state of zero modes, as is illustrated here in two-dimensional model field theories.
Capacity of Systems with Queue-Length Dependent Service Quality

We study the information-theoretic limit of reliable information processing by a server with queue-length dependent quality of service. We define the capacity for such a system as the number of bits reliably processed per unit time, and characterize it in terms of queuing system parameters. We also characterize the distributions of the arrival and service processes that maximize and minimize the capacity of such systems in a discrete-time setting. For arrival processes with at most one arrival per time slot, we observed a minimum around the memoryless distribution. We also studied the case of multiple arrivals per time slot, and observed that burstiness in arrival has adverse effects on the system. The problem is theoretically motivated by an effort to incorporate the notion of reliability in queuing systems, and is applicable in the contexts of crowdsourcing, multimedia communication, and stream computing.
Gender differences in interpersonal and intrapersonal competitive behavior

Abstract Gender differences in competitive behavior continue to be documented by economists and other social scientists; however, the bulk of the research addresses competition with others and excludes other economically relevant contests. In this paper, we ask: how does gender affect how individuals react to competing against themselves? In a laboratory experiment in which some subjects compete against others and some compete against themselves, we find women select into intrapersonal competition at significantly higher rates than interpersonal competition and comparatively more than men. In addition, we find that while perseverance or “grit” does not explain the gender difference in behavior, risk attitudes have some explanatory power.
Consumer Willingness to Pay for Tennessee Certified Beef

Although Tennessee has Advanced Master Beef Producer (AMBP) and Beef Quality Assurance (BQA) certifications for cattle producers, currently there is no state-certified beef labeling program. A choice experiment was administered to Tennessee consumers to determine their willingness to pay for Tennessee Certified Beef (TCB) and other attributes such as labels indicating producer participation in AMBP and BQA. Random parameter logit model results indicate consumers most valued TCB steak and no-hormones-administered ground beef. Consumers also valued many labels when appearing alongside the TCB label. The impact of providing participants label definitions prior to the choice experiment was examined.
Opacity of the Universe to High-Energy Photons

Based on observational data, the spectra of cosmic radio, microwave, infrared, optical, and x-ray photons are estimated. The absorption probability per unit path length by the process of pair production in photon-photon collisions is then computed as a function of energy for high-energy photons traversing this photon gas, using the results of the previous paper. These calculations show that there should be a dip in the intensity of the high-energy cosmic photon spectrum by about a factor of 10 between ${10}^{12}$ and ${10}^{13}$ eV due to absorption by optical (\ensuremath{\sim} a few eV) photons. Above ${10}^{14}$ eV, the high-energy cosmic photon spectrum should essentially cut off because of the strong absorption by the cosmic 3\ifmmode^\circ\else\textdegree\fi{}K blackbody photons, and at higher energies by the cosmic radio photons.
COMORBIDITY EFFECTS ON SHOULDER ARTHROPLASTY COSTS: ANALYSIS OF A NATIONWIDE PRIVATE PAYER INSURANCE DATASET

Purpose The purpose of this study was to evaluate the effect of common medical comorbidities on the reimbursements of different shoulder arthroplasty procedures Methods We conducted a retrospective query of a private payer insurance claims database of prospectively collected data (PealDiver). Our search included the Current Procedural Terminology Codes (CPT) and International Classification of Disease (ICD) ninth edition codes for Total Shoulder Arthroplasty (TSA), Hemiarthroplasty (HA) and Reverse Shoulder Arthroplasty (RSA). Medical comorbidities were also searched for through ICD codes. The comorbidities selected for analysis were obesity, morbid obesity, hypertension, smoking, diabetes mellitus, hyperlipidemia, atrial fibrillation, chronic obstructive pulmonary disease (COPD), cirrhosis, depression and chronic kidney disease (CKD) (excluding end stage renal disease). The study period comprised claims from 2010 to 2014. The reimbursement charges of the day of surgery, 90-day global period and 90-day period excluding the initial surgical day of each comorbidity were analyzed and compared. Statistical analysis was conducted trough analysis of variance (ANOVA) when the data was normally distributed or through Kruskal-Wallis comparison when it was not. An alpha value of less than 0.05 was deemed as significant. Results Comorbidities did not have a significant effect on same day reimbursements (Figure 1), but instead caused a significant effect on the 90-day global period reimbursements in the TSA and RSA cohorts (figure 2). For TSA and RSA the highest reimbursed patients at the 90-day period following surgery were the ones that had a diagnosis of Hepatitis C followed by atrial fibrillation and later COPD. For HA the same was true in the following order: Hepatitis C, Cirrhosis and atrial fibrillation (Figure 3). Conclusion Shoulder arthroplasty reimbursements are significantly affected by comorbidities at time intervals following the initial surgical day. For figures/tables, please contact authors directly.
Sacral Variability in Tailless Species: Homo sapiens and Ochotona princeps

Homo sapiens is variable in number of sacral vertebrae, and this variability can lead to obstetrical complication. This study uses the comparative method to test the hypothesis that sacral variability in H. sapiens is associated with absence of a tail. Three species of lagomorphs are studied: Ochotona princeps (N = 271), which is tailless, and Lepus californicus (N = 212) and Sylvilagus audubonii (N = 206), which have tails. Results show that O. princeps has (1) higher diversity index for number of sacral vertebrae (0.49) compared to L. californicus (0.25) and S. audubonii (0.26) and (2) significantly higher percentage of individuals with the species-specific nonmodal number of sacral vertebrae (43.9%) compared to L. californicus (14.2%) and S. audubonii (15.5%). Comparison of H. sapiens (N = 1,030; individuals of age 20-39 years) with O. princeps shows similarities between the species in diversity index (also 0.49 in H. sapiens) and percentage of individuals with nonmodal number of sacral vertebrae (37.3% in H. sapiens). Homeotic transformation best explains the results. H. sapiens and O. princeps show propensity for caudal shift at the sacral-caudal border (i.e., homeotic transformation of the first caudal vertebra to a sacral vertebra). Caudal and cranial shift among presacral vertebrae increases or decreases this propensity, respectively. Increase in number of sacral vertebrae in H. sapiens by homeotic transformation reduces pelvic outlet capacity and can be obstetrically hazardous. Anat Rec, 300:798-809, 2017. © 2017 Wiley Periodicals, Inc.
Strategies of Election Rigging: Trade-Offs, Determinants, and Consequences

Ideally, elections should peacefully allocate political power and remove bad leaders from office. We study how the electoral mechanism performs when the government can rig elections by manipulating the electoral process ex ante and by falsifying election returns ex post. The extent to which elections contribute to peace and accountability depends on how incumbents trade-off between the two strategies given the institutional constraints. An option to falsify election results without being exposed increases the risk of conflict even if that option is not realized in equilibrium, but an option to use ex-ante manipulation reduces the risk of conflict. Imposing constraints on one strategy of election rigging when the incumbent can substitute it with another leads to perverse trade-offs: Constraining ex-ante manipulation raises the risk of conflict, but may improve accountability. Making ex-post falsification more difficult to hide improves the prospect of peace, but worsens accountability.
Earnings volatility and 401(k) contributions

Using longitudinal Survey of Income and Program Participation data linked to Social Security Administration administrative records from 2009 and 2012, we find negative economic shocks cause 401(k) contribution behavior to react in ways consistent with reactions to fear and past trauma. If employees participating in 401(k) plans did not experience real earnings declines or unemployment spells between 2009 and 2012, then their contribution rates would have been 5% higher and each person would have contributed US $193 more toward their defined contribution plan accounts. We conclude that previous studies may have swung too far in emphasizing inertia as a primary behavior trait explaining workers’ 401(k) plan engagement. Reactive behavior to protect living standards by reducing retirement savings is also important.
Worth the wait? Delay in CEO succession after unplanned CEO departures

Abstract This paper analyzes changes in shareholder value and firm performance in relation to the delay (or lack thereof) in CEO succession. I find that, on average, delay in succession is associated with stronger performance after an unplanned CEO departure. However, the value effect of delay varies and not all firms benefit from long delay. Firms with higher stock price volatility and those whose CEO is hired away experience lower performance. These results suggest that delay affects frictions in the CEO labor market. The impact of delay is particularly important when firms have no succession plan in place.
Extending Hypermedia Conceptual Models to Support Hyperknowledge Specifications

Most multimedia documents available today are agnostic to data semantics. Moreover, their specification language offers little to ease authoring of meaningful content. In this paper, we present the main entities of a new version (3.1) of the Nested Context Model (NCM), which concentrate efforts at integrating support for enriched concept description to the model. These extensions enable the specification of relationships between concept descriptions and multimedia content in the hypermedia way, composing what we call hyperknowledge in this paper. NCM previous version (3.0) is a hypermedia conceptual model. NCL (Nested Context Language), which is part of international standards and ITU recommendations, was engineered according to NCM 3.0 definitions. The extensions discussed in this paper contribute not only for advances in the NCL, but mainly as a conceptual model for hyperknowledge document engineering.
Bringing the Internet to Your Database: Using SQL Server 2000 and XML to Build Loosely-Coupled Systems

Abstract: Loosely-coupled, distributed system architectures need to be flexible enough to allow individual components to join or leave the heterogeneous conglomerate of services and components and to change their internal design and data models without jeopardizing the whole architecture. A well-established approach is to use XML as the lingua franca for the integration layer that hides the heterogeneity among the components and provides the glue that allows the individual components to take part in the loosely integrated system. This presentation focuses on how to provide the basic technology to enable a relational database to become a component in such loosely-coupled systems and it will provide an overview over the features that are needed to provide access via HTTP and XML.
Candidate entry and political polarization: An experimental study

We report the results of a laboratory experiment based on a citizen–candidate model with private information about ideal points. Inefficient political polarization is observed in all treatments; that is, citizens with extreme ideal points enter as candidates more often than moderate citizens. Second, less entry occurs, with even greater polarization, when voters have directional information about candidates’ ideal points, using ideological party labels. Nonetheless, this directional information is welfare enhancing because the inefficiency from greater polarization is outweighed by lower entry expenses and better voter information. Third, entry rates are decreasing in group size and the entry cost. These findings are all implied by properties of the unique symmetric Bayesian equilibrium cutpoint pair of the entry game. Quantitatively, we observe too little (too much) entry when the theoretical entry rates are high (low). This general pattern of observed biases in entry rates is implied by logit quantal response equilibrium.
An algorithm for the rapid numerical evaluation of Bessel functions of real orders and arguments

We describe a method for the rapid numerical evaluation of the Bessel functions of the first and second kinds of nonnegative real orders and positive arguments. Our algorithm makes use of the well-known observation that although the Bessel functions themselves are expensive to represent via piecewise polynomial expansions, the logarithms of certain solutions of Bessel’s equation are not. We exploit this observation by numerically precomputing the logarithms of carefully chosen Bessel functions and representing them with piecewise bivariate Chebyshev expansions. Our scheme is able to evaluate Bessel functions of orders between 0 and 1,000,000,000 at essentially any positive real argument. In that regime, it is competitive with existing methods for the rapid evaluation of Bessel functions and has at least three advantages over them. First, our approach is quite general and can be readily applied to many other special functions which satisfy second order ordinary differential equations. Second, by calculating the logarithms of the Bessel functions rather than the Bessel functions themselves, we avoid many issues which arise from numerical overflow and underflow. Third, in the oscillatory regime, our algorithm calculates the values of a nonoscillatory phase function for Bessel’s differential equation and its derivative. These quantities are useful for computing the zeros of Bessel functions, as well as for rapidly applying the Fourier-Bessel transform. The results of extensive numerical experiments demonstrating the efficacy of our algorithm are presented. A Fortran package which includes our code for evaluating the Bessel functions is publicly available.
Aeroelastic Wingbox Stiffener Topology Optimization

This work considers a metallic aeroelastic wingbox model seeded with runout blade stiffeners along the skins. Topology optimization is conducted within the shell webs of the stiffeners in order to ...
The Trial of Joseph Dotterweich: The Origins of the “Responsible Corporate Officer” Doctrine

This article analyzes the origins of the “responsible corporate officer” doctrine: the trial of Joseph Dotterweich. That doctrine holds that an officer may be personally liable for the criminal act of a subordinate if the officer was, in some indefinite way, able to prevent the violation. Applying this doctrine, the prosecution of Dotterweich entailed strict liability for a strict liability offense. The underlying offenses—the interstate sale of one misbranded and adulterated drug and one misbranded drug—were said to be strict liability offenses. And then, with respect to Dotterweich as the corporation’s general manager, the government argued that he was strictly liable because he stood in “responsible relation” to the company’s acts. The government never tried to prove that the company, Buffalo Pharmacal, was negligent, nor did it try to prove that Dotterweich was negligent in his supervision of the employees of Buffalo Pharmacal. The prosecutor and judge were candid about this theory throughout the trial, although the judge conceded that it seemed bizarre and unfair. The defense lawyer repeatedly sought to inject what became known throughout the trial as the “question of good faith,” but was circumvented at almost every turn. What would thus seem to be the crux of any criminal trial—the personal fault of the defendant—was carefully shorn from the jury’s consideration. The government’s theory was so at odds with intuitive notions of liability and blame that, as one probes into the case, and looks at the language used in the government’s appellate briefs, imputations of moral fault inevitably crept in. Yet the government was not entitled to make such accusations, as it had pruned moral considerations from the trial. The article argues that the responsible corporate officer doctrine can never enjoy a secure place in our legal system. First, the doctrine is at a minimum in tension with, and often in direct opposition to, basic principles of the criminal law; and second, the doctrine fails, when followed to its logical conclusions, to accord with basic notions of fair play. The article concludes that the responsible corporate officer doctrine is either unnecessary, in cases in which the evidence establishes personal fault, or unjust, in cases in which it creates liability in the absence of personal fault through the unspecified notion of “responsibility.” The Dotterweich case illustrates what is contemplated by the latter possibility, and why it is problematic in any judicial system that purports, in the words of the Model Penal Code, “to safeguard conduct that is without fault from condemnation as criminal.”
General Analysis on the Impact of Phase-Skew in Time-Interleaved ADCs

Time-interleaved analog-to-digital converters (TIADCs) are sensitive to various mismatches that distort the sampled signal. Standard TIADC analysis assumes a narrowband sinusoidal input, which may result in pessimistic matching constraints for system-specific ADCs used with wideband input signals. Closed-form expressions bounding the acceptable phase-skew for wideband systems are derived and are validated through simulations. In one of the examples presented, it is shown that standard analysis can overconstrain the bound on acceptable phase-skew variance by a factor of three.
The Effects of an Activist Policy on Macroeconomic Stability

Abstract This paper investigates the consequences of activist policy in a small, aggregate macroeconomic model which embodies traditional hypotheses of price and output determination. It is shown that deterministic control problems with inflation and full employment as objectives may be solved, but multiple-target stochastic control problems will lead to instability in both the targets and the policy instrument. These propositions result from the characteristics of the stochastic disturbances in inflation and output equations. A small model is estimated, and its error processes analyzed, to determine that these characteristics may reasonably be replicated in an empirical model. The instability propositions thus appear to have relevance to the formulation of current activist policy.
TRIM9-dependent ubiquitination of DCC constrains kinase signaling, exocytosis, and axon branching.

In the presence of netrin, tripartite motif protein 9 (TRIM9) promotes deleted in colorectal cancer (DCC) clustering, but TRIM9-dependent ubiquitination of DCC is reduced. Loss of ubiquitination pr...