cssi/SciSciGPT-SciSciNet huggingface dataset:
Pricing to Maximize Revenue and Welfare Simultaneously in Large Markets

We study large markets with a single seller who can produce many types of goods, and many multi-minded buyers. The seller chooses posted prices for its many items, and the buyers purchase bundles to maximize their utility. For this setting, we consider the following questions: what fraction of the optimum social welfare does a revenue maximizing solution achieve? Are there pricing mechanisms which achieve both good revenue and good welfare simultaneously? To address these questions, we give envy-free pricing schemes which are guaranteed to result in both good revenue and welfare, as long as the buyer valuations for the goods they desire have a nice although reasonable structure, e.g., the aggregate buyer demand has a monotone hazard rate or is not too convex. We also show that our pricing schemes have implications for any solution which achieves high revenue: specifically that in many settings, prices that maximize approximately profit also result in high social welfare. Our results holds for general multi-minded buyers in large markets with production costs; we also provide improved guarantees for the important special case of unit-demand buyers.
The end of Midcontinent Rift magmatism and the paleogeography of Laurentia

Paleomagnetism of the North American Midcontinent Rift provides a robust paleogeographic record of Laurentia (cratonic North America) from ca. 1110 to 1070 Ma, revealing rapid equatorward motion of the continent throughout rift magmatism. Existing age and paleomagnetic constraints on the youngest rift volcanic and sedimentary rocks have been interpreted to record a slowdown of this motion as rifting waned. We present new paleomagnetic and geochronologic data from the ca. 1090–1083 Ma “late-stage” rift volcanic rocks exposed as the Lake Shore Traps (Michigan), the Schroeder-Lutsen basalts (Minnesota), and the Michipicoten Island Formation (Ontario). The paleomagnetic data allow for the development of paleomagnetic poles for the Schroeder-Lutsen basalts (187.8°E, 27.1°N; A 95 = 3.0°, N = 50) and the Michipicoten Island Formation (174.7°E, 17.0°N; A 95 = 4.4°, N = 23). Temporal constraints on late-stage paleomagnetic poles are provided by high-precision, 206 Pb- 238 U zircon dates from a Lake Shore Traps andesite (1085.57 ± 0.25 Ma; 2s internal errors), a Michipicoten Island Formation tuff (1084.35 ± 0.20 Ma) and rhyolite (1083.52 ± 0.23 Ma), and a Silver Bay aplitic dike from the Beaver Bay Complex (1091.61 ± 0.14 Ma), which is overlain by the Schroeder-Lutsen basalt flows. These Michipicoten Island Formation dates are the youngest yet obtained from Midcontinent Rift volcanic rocks and indicate that rift magmatism was active for at least 25 m.y. The addition of these late-stage paleomagnetic poles to the Laurentian apparent polar wander path suggests that rapid motion of Laurentia continued throughout the entirety of rift volcanism.
Equilibration in the Kac Model Using the GTW Metric d_2

We use the Fourier based Gabetta–Toscani–Wennberg metric $$d_2$$ to study the rate of convergence to equilibrium for the Kac model in 1 dimension. We take the initial velocity distribution of the particles to be a Borel probability measure $$\mu $$ on $$\mathbb {R}^n$$ that is symmetric in all its variables, has mean $$\vec {0}$$ and finite second moment. Let $$\mu _t(dv)$$ denote the Kac-evolved distribution at time t, and let $$R_\mu $$ be the angular average of $$\mu $$ . We give an upper bound to $$d_2(\mu _t, R_\mu )$$ of the form $$\min \left\{ B e^{-\frac{4 \lambda _1}{n+3}t}, d_2(\mu ,R_\mu )\right\} ,$$ where $$\lambda _1 = \frac{n+2}{2(n-1)}$$ is the gap of the Kac model in $$L^2$$ and B depends only on the second moment of $$\mu $$ . We also construct a family of Schwartz probability densities $$\{f_0^{(n)}: \mathbb {R}^n\rightarrow \mathbb {R}\}$$ with finite second moments that shows practically no decrease in $$d_2(f_0(t), R_{f_0})$$ for time at least $$\frac{1}{2\lambda }$$ with $$\lambda $$ the rate of the Kac operator. We also present a propagation of chaos result for the partially thermostated Kac model in Tossounian and Vaidyanathan (J Math Phys 56(8):083301, 2015).
On the Notions of Facets, Weak Facets, and Extreme Functions of the Gomory–Johnson Infinite Group Problem

We investigate three competing notions that generalize the notion of a facet of finite-dimensional polyhedra to the infinite-dimensional Gomory–Johnson model. These notions were known to coincide for continuous piecewise linear functions with rational breakpoints. We show that two of the notions, extreme functions and facets, coincide for the case of continuous piecewise linear functions, removing the hypothesis regarding rational breakpoints. We then separate the three notions using discontinuous examples.
Unsupervised Pretraining for Sequence to Sequence Learning

This work presents a general unsupervised learning method to improve the accuracy of sequence to sequence (seq2seq) models. In our method, the weights of the encoder and decoder of a seq2seq model are initialized with the pretrained weights of two language models and then fine-tuned with labeled data. We apply this method to challenging benchmarks in machine translation and abstractive summarization and find that it significantly improves the subsequent supervised models. Our main result is that pretraining improves the generalization of seq2seq models. We achieve state-of-the-art results on the WMT English→German task, surpassing a range of methods using both phrase-based machine translation and neural machine translation. Our method achieves a significant improvement of 1.3 BLEU from th previous best models on both WMT’14 and WMT’15 English→German. We also conduct human evaluations on abstractive summarization and find that our method outperforms a purely supervised learning baseline in a statistically significant manner.
Constraints on bounded motion and mutual escape for the full 3-body problem

When gravitational aggregates are spun to fission they can undergo complex dynamical evolution, including escape and reconfiguration. Previous work has shown that a simple analysis of the full 2-body problem provides physically relevant insights for whether a fissioned system can lead to escape of the components and the creation of asteroid pairs. In this paper we extend the analysis to the full 3-body problem, utilizing recent advances in the understanding of fission mechanics of these systems. Specifically, we find that the full 3-body problem can eject a body with as much as 0.31 of the total system mass, significantly larger than the 0.17 mass limit previously calculated for the full 2-body problem. This paper derives rigorous limits on a fissioned 3-body system with regards to whether fissioned system components can physically escape from each other and what other stable relative equilibria they could settle in. We explore this question with a narrow focus on the Spherical Full Three Body Problem studied in detail earlier.
Rank Matching for Multihop Multiflow

We study the degrees of freedom (DoF) of the layered $2 \times 2 \times 2$ multiple-input-multiple-output (MIMO) interference channel where each node is equipped with arbitrary number of antennas, the channels between the nodes have arbitrary rank constraints, and subject to the rank-constraints the channel coefficients can take arbitrary values. The DoF outer bounds reveal a fundamental rank-matching phenomenon, reminiscent of impedance matching in circuit theory. It is well known that the maximum power transfer in a circuit is achieved not for the maximum or minimum load impedance but for the load impedance that matches the source impedance. Similarly, the maximum DoF in the rank-constrained $2 \times 2 \times 2$ MIMO interference network is achieved not for the maximum or minimum ranks of the destination hop, but when the ranks of the destination hop match the ranks of the source hop. In fact, for mismatched settings of interest, the outer bounds identify a DoF loss penalty that is precisely equal to the rank-mismatch between the two hops. For symmetric settings, we also provide achievability results to show that along with the min-cut max-flow bounds, the rank-mismatch bounds are the best possible, i.e., they hold for all channels that satisfy the rank-constraints and are tight for almost all channels that satisfy the rank-constraints. Limited extensions—from sum-DoF to DoF region, from 2 unicasts to $X$ message sets, from 2 hops to more than 2 hops and from 2 nodes per layer to more than 2 nodes per layer—are considered to illustrate how the insights generalize beyond the elemental $2 \times 2 \times 2$ channel model.
The interplay between free sampling and word of mouth in the online software market

Free sampling in digital format has become a common business practice in the online market offering consumers first-hand experience with products, due to its low marginal cost and extensive online distribution. At the same time, online word of mouth (WOM) has also been a prevalent strategy on the Internet for increasing product visibility and providing trustworthy product information. Those two online marketing strategies are generally considered to stand alone by marketers and prior research. Nevertheless, by drawing on integrated information response theory as well as theories for explaining online consumers' review sharing, we argue that free sampling complements WOM in the online market by amplifying its sales effect and facilitating its implementation. We provide supportive empirical evidence through a Bayesian analysis of software free sampling on CNET Download.com (CNETD) and sales and WOM from Amazon.com over a 25-week data set. Our results show that adoptions of CNETD free sampling positively interact with Amazon WOM in influencing Amazon software sales. In addition, more adoptions of CNETD free sampling lead to a larger volume of Amazon WOM, and this impact is more significant for less popular products. These findings contribute to our understanding of free sampling in the online market such that, in addition to its direct sales effect, free sampling can also potentially affect sales through influencing online WOM. Therefore, we suggest that marketers evaluate the free sampling strategy by including its interplay with online WOM and apply low-cost free sampling to facilitate the relatively more expensive online WOM marketing strategy, especially for unpopular products. Free sampling complements WOM in the online market in two ways.More adoptions of free sampling amplify sales effect of WOM in the online market.More adoptions of digital free sampling help attract more online conversations.
Association between any major discrimination and current cigarette smoking among adult African American men

ABSTRACTBackground: Findings from previous research has demonstrated a positive relationship between interpersonal discrimination and cigarette smoking. Cigarette smoking is proposed to be an externalizing coping mechanism used to alleviate discrimination. At the national level, it is unclear if discrimination is associated with cigarette smoking among African American men. Objective: The aim of the study was to examine the association between discrimination and cigarette smoking among a national sample of African American men. Methods: Using data from the National Survey of American Life (n = 1,271), multivariable logistic regression was used to examine the relationship between discrimination and cigarette smoking. Results: Thirty-two percent of the men were current smokers. Controlling for everyday discrimination, major discrimination, major stress, depressive symptoms, age, being married, household income, and education, African American men who experienced major discrimination had a higher odd of bein...
Finite sample posterior concentration in high-dimensional regression

We study the behavior of the posterior distribution in high-dimensional Bayesian Gaussian linear regression models having p n, where p is the number of predictors and n is the sample size. Our focus is on obtaining quantitative finite sample bounds ensuring sufficient posterior probability assigned in neighborhoods of the true regression coefficient vector (β0) with high probability. We assume that β0 is approximately S-sparse and also obtain universal bounds, which provide insight into the role of the prior in controlling concentration of the posterior. Based on these finite sample bounds, we examine the implied asymptotic contraction rates for several examples, showing that sparsely structured and heavytail shrinkage priors exhibit rapid contraction rates. We also demonstrate that a stronger result holds for the sparsity(S)-Gaussian1 prior. These types of finite sample bounds provide guidelines for designing and evaluating priors for high-dimensional problems.
Keeping It in the Family: Lineage Organization and the Scope of Trust in Sub-Saharan Africa

We present evidence that the traditional structure of society is an important determinant of the scope of trust today. Within Africa, individuals belonging to ethnic groups that organized society using segmentary lineages exhibit a more limited scope of trust, measured by the gap between trust in relatives and trust in non-relatives. This trust gap arises because of lower levels of trust in non-relatives and not higher levels of trust in relatives. A causal interpretation of these correlations is supported by the fact that the effects are primarily found in rural areas where these forms of organization are still prevalent.
Max-value Entropy Search for Efficient Bayesian Optimization

Entropy Search (ES) and Predictive Entropy Search (PES) are popular and empirically successful Bayesian Optimization techniques. Both rely on a compelling information-theoretic motivation, and maximize the information gained about the $\arg\max$ of the unknown function; yet, both are plagued by the expensive computation for estimating entropies. We propose a new criterion, Max-value Entropy Search (MES), that instead uses the information about the maximum function value. We show relations of MES to other Bayesian optimization methods, and establish a regret bound. We observe that MES maintains or improves the good empirical performance of ES/PES, while tremendously lightening the computational burden. In particular, MES is much more robust to the number of samples used for computing the entropy, and hence more efficient for higher dimensional problems.
Array self calibration using multiple data sets

Existing array self-calibration techniques operate on data collected during a single time interval and require the number of active signals to be sufficiently large. This requirement can seldom be satisfied in practice. We extend self-calibration to operate across multiple time intervals which may contain different sets of signals. This makes it possible for self-calibration to work when the number of active signals per time interval is small.
q-EULERIAN POLYNOMIALS: EXCEDANCE NUMBER AND MAJOR INDEX

We derive a new q-analog of a classical formula for the exponential generating function of the Eulerian polynomials. This arose in our work on poset topology and was presented as a conjecture at the second author's FPSAC 2006 lecture. We have since proved our conjecture and a symmetric function generalization of it. Our q-Eulerian polynomials are the enumerators for the joint distribution of the excedance statistic and the major index. There is a vast literature on q-Eulerian polynomials that involves other combinations of Eulerian and Mahonian permutation statistics, but this is the first result to address the combination of excedance number and major index. Our proof involves an intriguing new class of symmetric functions and a bijection of Gessel and Reutenauer, which can be viewed as a necklace analog of Stanley's theory of P-partitions. We also discuss connections with (1) the representation of the symmetric group on the homology of a poset introduced by Bjorner and Welker, (2) the representation of the symmetric group on the cohomology of the toric variety associated with the Coxeter complex of the symmetric group, studied by Procesi, Stanley, Stembridge, Dolgachev and Lunts, (3) the enumeration of words with no adjacent repeats studied by Carlitz, Scoville and Vaughan and by Dollhopf, Goulden and Greene, and (4) Stanley's chromatic symmetric functions.
How much can CO2 emissions be reduced if fossil fuel subsidies are removed

Abstract This paper analyzes consumers' price elasticities of demand for fossil fuels, and how a reduction of fossil fuel subsidies can lead to important reduction in CO 2 emissions for various groups of countries that have relatively high fossil fuel subsidies and notably on diesel, including countries in the Middle East and North Africa (MENA). These countries continue to maintain significant levels of fuel subsidies, with Iran and Saudi Arabia being the largest contributors to CO 2 emissions. This paper illustrates that fuel price policy reforms by these countries would be an important instrument for both climate and economic policies. We estimate that a reduction in subsidies to both gasoline and diesel by about 20 US$ cents per liter will lead to significant decreases in CO 2 emissions, both in the MENA region and globally. In Iran, for example, the reductions could be up to 90% and 50% of current emissions generated from diesel and gasoline consumption, respectively, and for Saudi Arabia, approximately 70% and 40%, respectively.
Granulosa Cell-Specific Androgen Receptors Are Critical Regulators of Ovarian Development and Function.

The physiological significance of androgens in female reproduction was unclear until female mice with global knockout of androgen receptor (AR) expression were found to have reduced fertility with abnormal ovarian function. However, because ARs are expressed in a myriad of reproductive tissues, including the hypothalamus, pituitary, and various ovarian cells, the role of tissue-specific ARs in regulating female fertility remained unknown. To examine the importance of ovarian ARs in female reproduction, we generated granulosa cell (GC)- and oocyte-specific AR-knockout (ARKO) mice by crossing AR-flox mice with MisRIIcre (GC-specific) or growth differentiation factor growth differentiation factor-9cre (oocyte-specific) mice. Relative to heterozygous and wild-type mice, GC-specific ARKO mice had premature ovarian failure and were subfertile, with longer estrous cycles and fewer ovulated oocytes. In addition, ovaries from GC-specific knockout mice contained more preantral and atretic follicles, with fewer antral follicles and corpus lutea. Finally, in vitro growth of follicles from GC-specific AR-null mice was slower than follicles from wild-type animals. In contrast to GC-specific AR-null mice, fertility, estrous cycles, and ovarian morphology of oocyte-specific ARKO mice were normal, although androgens no longer promoted oocyte maturation in these animals. Together, our data indicate that nearly all reproductive phenotypes observed in global ARKO mice can be explained by the lack of AR expression in GCs. These GC-specific ARs appear to promote preantral follicle growth and prevent follicular atresia; thus they are essential for normal follicular development and fertility.
Explicit determination of piezoelectric Eshelby tensors for a spheroidal inclusion

Abstract In this paper, by systematically treating the integrals involved in the piezoelectric inclusion problem, we have obtained explicit results for the piezoelectric Eshelby tensors for a spheroidal inclusion aligned along the axis of the anisotropy in a transversely isotropic piezoelectric material. This problem was first treated by Dunn and Wienecke (Int. J. Solids Struct. 34 (27), 3571–3582) using a Green's function approach, which closely follows Withers' approach (Phil. Mag. A 59 (4), 759–781) for an ellipsoidal inclusion problem in a transversely isotropic elastic medium. The same problem was recently treated by Michelitsch and Levin (Eur. Phys. J. B 14, 527–533), who also used a Green's function approach. In this paper, we also obtain the piezoelectric Eshelby tensors for a spheroidal inclusion explicitly, but using a different approach. The method is a direct extension of a more unified approach, which has been recently developed by Mikata (Int. J. Engng. Sci. 38, 608–641), which is based on Deeg's results (Ph.D. dissertation, Stanford University) on a piezoelectric inclusion problem. The main advantage of this method is that it is more straightforward and simpler than Dunn and Wienecke (1996) , or Michelitsch and Levin (2000) , and the results are a little bit more explicit than their solutions. The key step of this paper is an analytical evaluation of several integrals, which was made possible after a careful treatment of a certain bi-cubic equation.
Learning Invariant Feature Spaces to Transfer Skills with Reinforcement Learning

People can learn a wide range of tasks from their own experience, but can also learn from observing other creatures. This can accelerate acquisition of new skills even when the observed agent differs substantially from the learning agent in terms of morphology. In this paper, we examine how reinforcement learning algorithms can transfer knowledge between morphologically different agents (e.g., different robots). We introduce a problem formulation where two agents are tasked with learning multiple skills by sharing information. Our method uses the skills that were learned by both agents to train invariant feature spaces that can then be used to transfer other skills from one agent to another. The process of learning these invariant feature spaces can be viewed as a kind of "analogy making", or implicit learning of partial correspondences between two distinct domains. We evaluate our transfer learning algorithm in two simulated robotic manipulation skills, and illustrate that we can transfer knowledge between simulated robotic arms with different numbers of links, as well as simulated arms with different actuation mechanisms, where one robot is torque-driven while the other is tendon-driven.
Charitable Giving in Nonprofit Service Associations: Identities, Incentives, and Gender Differences:

Nonprofit service associations, such as the Lions Clubs, Rotaries, and Kiwanis, provide collective goods. Membership in a service association involves two essential elements: members’ shared intere...
ARE SMALLER HIP RESURFACINGS AT HIGHER RISK FOR FAILURE? A RETRIEVAL ANALYSIS

Young osteoarthritic male patients have been considered the ideal candidates for Metal-on-Metal (MoM) hip resurfacing arthroplasty (HRA), based on generally good long term results. In contrast, hip resurfacing in young female patients has become controversial. Recently, one implant manufacturer withdrew 46mm and smaller components, citing poorer than expected 10 year outcomes in females with smaller HRAs. Whether this difference is related to gender or to component size is still debated. Possible reasons for higher failure rates reported in females include higher rates of hip dysplasia, poorer bone quality and the risk of higher wear in some smaller sized implants with low cup coverage angles. We reviewed HRA revision specimens with the aim of comparing mode of failure, time to revision, femoral cement characteristics and acetabular bone attachment in specimens larger and smaller than 46mm and from male versus female patients. Methods The study included all of the MoM HRA devices in our collection. Of the 284 hip resurfacing devices with complete clinical information, 131 were from male and 153 from female patients. Femoral sizes ranged from 36 – 58mm, median and mode 46mm; median size in females was 44 and 50mm in males. Time to failure ranged from 1 to 178 months, median 24 mos. Seven designs were represented but the majority were Conserve Plus (n=105 WMT, USA) and BHR (n=78 Smith & Nephew, USA) which differ in cementing technique. 131 femoral components were sectioned and the width of the cement mantle and the amount of cement in the head were measured. Where available, the amount of bone attached to the cup porous surface (n=91), tissue ALVAL scores (n=75) and bearing wear depth (n=138) were included in the multivariate analysis. Results As a function of gender, there were no significant differences in time to revision, cement measurements or ALVAL scores. Wear depth was significantly higher in females (femoral 41um vs 21um; cup 50um vs 16um, p=0.05). As a function of size (46 and less = small), the <46mm group had a slightly shorter time to revision, 30 vs 38 months, p=0.04). Bone ingrowth ranged from 0 to 60% (Figure 1) and significantly less bone attachment was noted in both the smaller and larger components (p = 0.001). Other characteristics were similar in both groups. When wear-related failure modes (cup malposition, lysis, high ions) were compared, no differences between male and female or large vs small were found. The amount of cement in the femoral heads covered a wide range but femoral loosening or fracture rates were not different as a function of size or gender. Conclusion This review of 248 revised HRAs from multiple surgeons, designs and modes of failure found no clear evidence that smaller HRA components were at higher risk of earlier failure or for any particular failure mode. The small components in this cohort were not more likely to have wear-related failures but of note, very few of these HRAs had implants with low coverage angles in the small sizes.
Facade: Auto-generating Tactile Interfaces to Appliances

Common appliances have shifted toward flat interface panels, making them inaccessible to blind people. Although blind people can label appliances with Braille stickers, doing so generally requires sighted assistance to identify the original functions and apply the labels. We introduce Facade - a crowdsourced fabrication pipeline to help blind people independently make physical interfaces accessible by adding a 3D printed augmentation of tactile buttons overlaying the original panel. Facade users capture a photo of the appliance with a readily available fiducial marker (a dollar bill) for recovering size information. This image is sent to multiple crowd workers, who work in parallel to quickly label and describe elements of the interface. Facade then generates a 3D model for a layer of tactile and pressable buttons that fits over the original controls. Finally, a home 3D printer or commercial service fabricates the layer, which is then aligned and attached to the interface by the blind person. We demonstrate the viability of Facade in a study with 11 blind participants.
Unifying Relations for Scattering Amplitudes

We derive new amplitudes relations revealing a hidden unity among a wideranging variety of theories in arbitrary spacetime dimensions. Our results rely on a set of Lorentz invariant differential operators which transmute physical tree-level scattering amplitudes into new ones. By transmuting the amplitudes of gravity coupled to a dilaton and two-form, we generate all the amplitudes of Einstein-Yang-Mills theory, Dirac-Born-Infield theory, special Galileon, nonlinear sigma model, and biadjoint scalar theory. Transmutation also relates amplitudes in string theory and its variants. As a corollary, celebrated aspects of gluon and graviton scattering like color-kinematics duality, the KLT relations, and the CHY construction are inherited traits of the transmuted amplitudes. Transmutation recasts the Adler zero as a trivial consequence of the Weinberg soft theorem and implies new subleading soft theorems for certain scalar theories.
Deception as Competence: The Effect of Occupation on Ethical Judgment and Behavior

Existing research assumes that deception undermines a person’s trustworthiness and career prospects. Yet, in some occupations, deception persists, and deceptive individuals seem to advance. The cur...
Level 3 Assets and Credit Risk

We examine the impact of Level 3 assets held by nonfinancial companies on credit risk. Specifically, we investigate how the pricing uncertainty of Level 3 assets is reflected in credit ratings, corporate bond yield spreads, and incidences of bond covenants. We find that higher holdings of Level 3 assets are associated with lower credit ratings, higher yield spreads, especially for Level 3 assets sample, and incidences of bondholder-friendly covenants in the bond issues. Our findings are robust to the treatment of sample selection bias and the influence of macroeconomic factors. In addition, our direct test on the relation between the holdings of Level 3 assets and a firm’s distance-to-default shows that higher holdings of Level 3 assets reduce a firm’s distance-to-default. Overall, our findings support the view that Level 3 assets are perceived as increasing credit risk in the bond market.
Understanding Integer Overflow in C/C++

Integer overflow bugs in C and C++ programs are difficult to track down and may lead to fatal errors or exploitable vulnerabilities. Although a number of tools for finding these bugs exist, the situation is complicated because not all overflows are bugs. Better tools need to be constructed, but a thorough understanding of the issues behind these errors does not yet exist. We developed IOC, a dynamic checking tool for integer overflows, and used it to conduct the first detailed empirical study of the prevalence and patterns of occurrence of integer overflows in C and C++ code. Our results show that intentional uses of wraparound behaviors are more common than is widely believed; for example, there are over 200 distinct locations in the SPEC CINT2000 benchmarks where overflow occurs. Although many overflows are intentional, a large number of accidental overflows also occur. Orthogonal to programmers' intent, overflows are found in both well-defined and undefined flavors. Applications executing undefined operations can be, and have been, broken by improvements in compiler optimizations. Looking beyond SPEC, we found and reported undefined integer overflows in SQLite, PostgreSQL, SafeInt, GNU MPC and GMP, Firefox, LLVM, Python, BIND, and OpenSSL; many of these have since been fixed.
Stateless Puzzles for Real Time Online Fraud Preemption

The profitability of fraud in online systems such as app markets and social networks marks the failure of existing defense mechanisms. In this paper, we propose FraudSys, a real-time fraud preemption approach that imposes Bitcoin-inspired computational puzzles on the devices that post online system activities, such as reviews and likes. We introduce and leverage several novel concepts that include (i) stateless, verifiable computational puzzles, that impose minimal performance overhead, but enable the efficient verification of their authenticity, (ii) a real-time, graph based solution to assign fraud scores to user activities, and (iii) mechanisms to dynamically adjust puzzle difficulty levels based on fraud scores and the computational capabilities of devices. FraudSys does not alter the experience of users in online systems, but delays fraudulent actions and consumes significant computational resources of the fraudsters. Using real datasets from Google Play and Facebook, we demonstrate the feasibility of FraudSys by showing that the devices of honest users are minimally impacted, while fraudster controlled devices receive daily computational penalties of up to 3,079 hours. In addition, we show that with FraudSys, fraud does not pay off, as a user equipped with mining hardware (e.g., AntMiner S7) will earn less than half through fraud than from honest Bitcoin mining.
Biased Anisotropic Diffusion - A Unified Regularization and Diffusion Approach to Edge Detection

We present a global edge detection algorithm based on variational regularization. The algorithm can also be viewed as an anisotropic diffusion method. We thereby unify these two from the original outlook quite different methods. The algorithm to be presented moreover has the following attractive properties: 1) It only requires the solution of a single boundary value problem over the entire image domain—almost always a very simple (rectangular) region. 2) It converges to a solution of interest.
Nanophotonics technology and applications

This paper explores the role of nanotechnology with focus on nanophotonics in dielectric, metal, and semiconductor inhomogeneous composition materials, devices and subsystems for optical communications, information and signal processing, and sensing.
Clinical Significance of the Elevated Anion Gap

To determine the clinical significance of a high anion gap (more than 16 meq/liter), consecutive patients in whom electrolyte determinations were made in an emergency room and who had either a normal (8 to 16 meq/liter) (n = 571) or a high (n = 100) anion gap were contrasted. No differences were noted between the groups with regard to age or length of stay in the hospital, but in the group with a high anion gap, there was an increased severity and frequency of multiple electrolyte disorders, and higher general admission rates (66 percent with high anion gap versus 51 percent with normal anion gap, p less than 0.02), rates of admission to an intensive care unit (25 percent with high anion gap versus 14 percent with normal anion gap, p less than 0.03), and mortality within one week of admission (12 percent with high anion gap versus 0.5 percent with normal anion gap, p less than 0.001) as compared with the group with a normal anion gap. Notably, patients without severe electrolyte abnormalities and a high anion gap had higher admission rates and a 50-fold increased mortality rate as compared with the group without severe electrolyte disturbances and a normal anion gap. Thus, an elevated anion gap is associated with an increased severity of illness that is independent of concomitant severe electrolyte abnormalities. Patients with a normal or high anion gap that survived the first week of hospitalization were shown to have an extremely low risk for mortality.
Aspergillosis in 25 Renal Transplant Patients: Epidemiology, Clinical Presentation, Diagnosis, and Management

In immunocompromised renal transplant patients, aspergillosis can be a life-threatening opportunistic infection. During an 8-year period, 25 renal transplant recipients at the University of Minnesota Hospitals developed unequivocal invasive aspergillosis that occurred in epidemic-like patterns in immunocompromised patients throughout the hospital. The premortem diagnosis was made in only 14 of the 25 patients. Seventeen patients died, and three of the eight survivors lost their allografts. The prognosis was dependent upon the clinical pattern of illness: three clinical patterns emerged: (1) cavitary lung disease, (2) diffuse pulmonary disease, and (3) central nervous system disease. All patients in the latter two categories died. The best results were with those patients treated with both amphotericin B and excision of cavitary lung lesions. All three patients treated in this manner survived with functioning grafts. Traditionally, sputum cultures have been thought to be unreliable because Aspergillus is a common colonizer of the upper respiratory tract and a contaminant in laboratories. In this study, false positive sputum cultures were common. A positive sputum culture can be helpful, however, all patients with two positive sputum cultures proved to have invasive aspergillosis. In addition, 86% of patients with positive sputum cultures who were clinically ill proved to have invasive infection. Bronchoscopy is a useful technique to follow up a positive sputum culture or investigate negative sputum cultures with typical clinical patterns. Routine bronchoscopy, unfortunately, also yields a high incidence of false positive cultures. Since the use of covered brush bronchoscopy technique, however, no false positive transbronchial cultures have been found. Transbronchial biopsy is a useful adjunct and is proof of the presence of invasive disease when the results are positive. However, false negative results are also found. Overall, the highest diagnostic yield is obtained both with transbronchial lung biopsy and covered brush bronchoscopy culture. All eight patients with both these procedures were correctly identified as having invasive pulmonary aspergillosis.
Adaptive hierarchical clustering using ordinal queries

In many applications of clustering (for example, ontologies or clusterings of animal or plant species), hierarchical clusterings are more descriptive than a flat clustering. A hierarchical clustering over n elements is represented by a rooted binary tree with n leaves, each corresponding to one element. The subtrees rooted at interior nodes capture the clusters. In this paper, we study active learning of a hierarchical clustering using only ordinal queries. An ordinal query consists of a set of three elements, and the response to a query reveals the two elements (among the three elements in the query) which are "closer" to each other than to the third one. We say that elements x and x' are closer to each other than x" if there exists a cluster containing x and x', but not x". When all the query responses are correct, there is a deterministic algorithm that learns the underlying hierarchical clustering using at most n log2 n adaptive ordinal queries. We generalize this algorithm to be robust in a model in which each query response is correct independently with probability [Equation], and adversarially incorrect with probability 1 − p. We show that in the presence of noise, our algorithm outputs the correct hierarchical clustering with probability at least 1 − Δ, using O(n log n + n log(1/Δ)) adaptive ordinal queries. For our results, adaptivity is crucial: we prove that even in the absence of noise, every non-adaptive algorithm requires Ω(n3) ordinal queries in the worst case.
Infants With Congenital Adrenal Hyperplasia Are at Risk for Hypercalcemia, Hypercalciuria, and Nephrocalcinosis

Context Hypercalcemia is reported as a rare finding in adrenal insufficiency, but is not well described in congenital adrenal hyperplasia (CAH). Methods A retrospective chart review was conducted of patients with CAH diagnosed before the age of 2 years who had at least one recorded serum calcium measurement. Data from birth to 6 years of age were reviewed. Results Of the 40 patients who met inclusion criteria, 33 (82.5%) had at least one elevated calcium concentration and 21 (53%) had two or more elevated calcium concentrations. Of the 126 elevated serum calcium concentrations, the median was 10.9 mg/dL (range, 10.6 to 14.2 mg/dL). Median age at the last elevated calcium measurement was 5 months (range, 0.3 to 46 months). Serum calcium concentration was inversely related to age (r = -0.124; P = 0.004). Overall, calcium level positively correlated with 17-hydroxyprogesterone (17OHP) concentration (r = 0.170; P = 0.003), and this remained significant after adjusting for age (P < 0.05). However, patients had hypercalcemia with both high and low 17OHP concentrations. Serum calcium concentration also was positively related to glucocorticoid (r = 0.196; P = 0.012) and fludrocortisone (r = 0.229; P = 0.003) doses, and remained significant after age adjustment. Only seven patients were evaluated for hypercalciuria. Of these, six had at least one period of documented hypercalciuria. Three patients had nephrocalcinosis on renal ultrasound. Conclusion Children with CAH are at risk for developing hypercalcemia, hypercalciuria, and nephrocalcinosis. Further studies are needed to determine the broader prevalence and the etiology of hypercalcemia in CAH.
Studying the effect of multi-query functionality on a correlation-aware SQL-to-mapreduce translator

The advent of Big Data has prompted numerous solutions that aim to meet the needs pertaining to data with high volume, veracity, velocity and variety properties. The exponential growth in data has dictated a simpler and more scalable environment with high fault tolerance and control over availability. With this motivation in mind and as an alternative to relational databases, numerous Not-Only Structured Query Language (NoSQL) databases were conceived. Nonetheless, relational databases and their de facto language, Structured Query Language (SQL), are still prominent among wider user groups. This project ventures into bridging the gap between Hadoop and relational databases through allowing multi-query functionality to a SQL-to-MapReduce translator. This study includes an analysis of the modified translator's behavior under different sets of conditions. Our results suggest that the modified translator scales linearly as the data size increases.
Theory and Evidence on Employer Collusion in the Franchise Sector

In this paper we study the role of covenants in franchise contracts that restrict the recruitment and hiring of employees from other units within the same franchise chain in suppressing competition for workers. Based on an analysis of 2016 Franchise Disclosure Documents, we find that "no-poaching of workers agreements" are included in a surprising 58 percent of major franchisors' contracts, including McDonald's, Burger King, Jiffy Lube and H&R Block. The implications of these no-poaching agreements for models of oligopsony are also discussed. No-poaching agreements are more common for franchises in low-wage and high-turnover industries.
Design and Pricing of Discretionary Service Lines

For discretionary services, longer service duration implies higher service quality. We study the optimal design and pricing of discretionary service lines, a range of services that are vertically d...
Risk Comparison of Transporting Hazardous Materials in Unit Trains Versus Mixed Trains

This research developed an integrated, generalized risk analysis methodology for comparing hazardous materials transportation risk in unit trains versus mixed trains for the same amount of traffic demand. The risk methodology accounted for FRA track class, method of operation, annual traffic density, train length, speed, point of derailment, the number and placement of tank cars in a train, tank car placement, tank car safety design, and population density along the rail line. With these inputs, the methodology estimates train derailment rate, the probability of tank car derailment and release, and release consequence by train configuration. The analysis showed that tank car positions could affect the risk comparison between unit trains and mixed trains in transporting hazardous materials. In particular, if all tank cars were in positions that were least prone to derailment, distributing tank cars to many unit trains could reduce the overall risk. Otherwise, consolidating tank cars into unit trains could ...
Long-Term Survival of Good-Risk Germ Cell Tumor Patients After Postchemotherapy Retroperitoneal Lymph Node Dissection: A Comparison of BEP × 3 vs. EP × 4 and Treating Institution.

Abstract Background Patients with International Germ Cell Cancer Collaborative Group (IGCCCG) good-risk testicular cancer might receive either 4 cycles of etoposide and cisplatin (EP × 4) or 3 cycles of bleomycin, etoposide, and cisplatin (BEP × 3). We sought to examine differences in survival after retroperitoneal lymph node dissection (PC-RPLND) between patients who received EP × 4 compared with BEP × 3. Patients and Methods The Indiana University Testis Cancer database was queried to identify IGCCCG good-risk PC-RPLND patients who received either EP × 4 or BEP × 3 induction chemotherapy. The primary outcome was overall survival (OS). Kaplan–Meier plots were generated for the EP × 4 and BEP × 3 groups and compared using the log rank test. Cox regression analysis was used to determine risk of mortality. Results A total of 223 patients met inclusion criteria between 1985 and 2011. Induction chemotherapy consisted of EP × 4 in 45 (20%) patients and BEP × 3 in 178 (80%). Most patients (78%) received their chemotherapy at outside institutions and were subsequently referred for PC-RPLND. The location of treating institution did not influence outcomes significantly when similar chemotherapy regimens were compared in this good-risk cohort. The 10-year OS for the EP × 4 and BEP × 3 groups were 91% and 98%, respectively (log rank P Conclusion The regimen of BEP × 3 resulted in a trend toward improved survival, however, this did not reach statistical significance. The location of treating institution seems less important in this risk group of patients.
International isolation and regional inequality: Evidence from sanctions on North Korea

Abstract This paper examines how the spatial distribution of economic activity evolved within North Korea during a period of economic sanctions. Countries have used economic sanctions to isolate North Korea from the benefits of international trade and finance. China, however, has not imposed the sanctions, and consequentially has offset the trade restrictions imposed by other countries. I hypothesize three channels by which North Korea could have responded in this context: regional favoritism by the ruling elites, reallocation of commerce that reflects the trade diversion to China, and import substitution. Using nighttime lights from North Korea, I find that the capital city, trade hubs near China, and manufacturing cities become relatively brighter when sanctions increase. However, production shifts away from capital-intensive goods, potentially deterring industrial development. The results imply that despite the intention to target the ruling elites, sanctions may increase regional inequality at a cost to the already marginalized hinterlands.
The Energizing Nature of Work Engagement: Toward a New Need-Based Theory of Work Motivation

Abstract We present theory suggesting that experiences at work that meet employees’ expectations of need fulfillment drive work engagement. Employees have needs (e.g., a desire to be authentic) and they also have expectations for how their job or their organization will fulfill them. We argue that experiences at work that confirm employees’ need fulfillment expectations yield a positive emotional state that is energizing, and that this energy is manifested in employees’ behaviors at work. Our theorizing draws on a review of the work engagement literature, in which we identify three core characteristics of work engagement: (a) a positive emotional state that (b) yields a feeling of energy and (c) leads to positive work-oriented behaviors. These key themes provide the foundation for further theorizing suggesting that interactions at work confirm or disconfirm employees’ need fulfillment expectations, leading to different levels of engagement. We extend our theorizing to argue that confirmation, or disconfirmation, of different need expectations will yield emotional experience of varying magnitudes, with confirmation of approach-oriented need expectations exerting stronger effects than the confirmation of avoidance-oriented need expectations. We close with a review suggesting that organizational contextual features influence the expression of these needs, sustaining or undermining the positive emotional experiences that fuel work engagement.
The chinese saving rate: Long-term care risks, family insurance, and demographics

Abstract A general equilibrium model that properly captures the risks in old age, the role of family insurance, changes in demographics, and the productivity growth rate is capable of generating changes in the national saving rate in China that mimic the data well. Our findings suggest that the combination of the risks faced by the elderly and the deterioration of family insurance due to the one-child policy may account for approximately half of the increase in the saving rate between 1980 and 2010. Changes in the productivity growth rate account for the fluctuations in the saving rate during this period.