cssi/SciSciGPT-SciSciNet huggingface dataset:
Sovereign debt, government myopia, and the financial sector

What determines the sustainability of sovereign debt? We develop a model where myopic governments seek popularity but can nevertheless commit credibly to service external debt. They do not default when debt is low because they would lose access to debt markets and be forced to reduce spending; they do not default as debt builds up and net new borrowing becomes difficult, because of the adverse consequences from default to the domestic financial sector. More myopic governments default less often, but tax in a more distortionary way and increase the vulnerability of the domestic financial sector to future government debt default. The Author 2013. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com., Oxford University Press.
The Impact of Security Analysts' Monitoring and Marketing Functions on the Market Value of Firms

In this study, we examine the impact of security analysts' monitoring and marketing functions on firms' market value. We postulate that security analysts' monitoring of corporate performance helps motivate managers, thus reducing the agency costs associated with the separation of ownership and control. We also argue that the information intermediary function provided by security analysts helps expand the breadth of investor cognizance. Consistent with these conjectures, this study finds that analyst following exerts a significant and positive impact on firms' market value. We also find evidence that security analysts have a stronger incentive to follow stocks of high quality companies, since such stocks arc easier to market. Hence, the security analysis activities appear to be determined, in part, by the marketing considerations of brokerage companies.
Shifting corporate culture: executive stock ownership plan adoptions and incentives to meet or just beat analysts’ expectations

This paper investigates whether adoptions of executive stock ownership plans coincide with decreased incentives to meet or just beat analysts’ near-term EPS forecasts. Firms often assert that ownership plans focus executives on long-term performance. I find that the impact of these adoptions on meeting or just beating analysts’ EPS forecasts differs depending on whether the plan binds the CEO to reach ownership targets by a specified date. In particular, I find that firms that adopt plans requiring an increase in CEO ownership exhibit a lower propensity to meet or just beat earnings forecasts following plan adoptions. In contrast, firms that adopt plans that require no increase exhibit no change in the propensity to meet or just beat. The results suggest that firms use binding ownership plans to shift executives’ focus from near-term earnings benchmarks to long-term value creation.
Budgeting for Accountability: Municipal Budgeting for the 1990s

The emphasis of a public budget depends on the time and circumstances in which it is developed. During the 1990s, for example, the emphasis has increasingly been on accountability due to widespread public belief in recent years that government is uncontrollable and responds only to special interests. Over the past few years, local budgeters have begun to adapt to this new environment by improving the accountability of the budget to the public. This article summarizes some of the changes taking place and suggests some additional changes that could be adopted to make local budgeting more accountable.
I'm Losing Patience with your Site: The Impact of Information Scent and Time Constraints on Effort, Performance, and Attitudes

As competition increases in the online world, website owners will investigate ways in which they can attract more users. Additionally, many consumers suffer ever-increasing time limitations when browsing for a particular item on a website. Users can become frustrated and stressed when they are unable to find those items due to poor information scent, or semantic cues that are meant to lead to their goal. This paper presents and tests a theoretical model to predict how information scent can reduce the amount of stress that consumers experience when seeking information under time constraints. The study also demonstrates the relationships between information scent, time constraints, stress, performance and attitudes toward the website. Results indicate that while high information scent is an important design goal, scent can only be assessed by taking the user’s task into account.
The Limitations of Stock Market Efficiency: Price Informativeness and CEO Turnover

There is a tenuous link between market efficiency and economic efficiency in that stock prices are more informative when the information has less social value. We investigate this link in the context of CEO turnover. Our theoretical model predicts that, when the board’s monitoring intensity and the informed trader’s information decision are jointly endogenized, stock price informativeness is negatively related to the board’s monitoring effort. Our empirical tests provide supporting evidence for this negative effect. Moreover, using the passage of the Sarbanes–Oxley Act (SOX) as a quasi-natural experiment, we find that SOX, while strengthening corporate governance, has a negative effect on stock price informativeness, especially among firms with complex organizational structures.
Bringing African Voices into the Undergraduate African Politics Classroom

Many African politics courses rely heavily on readings authored by North American and European scholars. Scholarly and primary sources written or created by Africans are often underrepresented, and a similar problem persists across regionally focused politics courses. Yet a diversity of sources and perspectives are essential to providing students with a well-rounded understanding of African politics. This article offers a brief argument for the pedagogical benefits of increasing the number of African-authored materials in African politics courses and provides a list of suggested resources for instructors eager to diversify their own courses.
Unobserved Heterogeneity in Models of Competing Mortgage Termination Risks

∗∗∗ ∗∗∗ This article extends unobserved heterogeneity to the multinomial logit (MNL) model framework in the context of mortgages terminated by refinance, move or default. It tests for the importance of unobserved heterogeneity when borrower characteristics such as income, age and credit score are included to capture lender-observed heterogeneity. It does this by comparing the proportional hazard model to MNL with and without mass-point estimates of unobserved heterogeneous groups of borrowers. The mass-point mixed hazard (MMH) model yields larger and more significant coefficients for several important variables in the move model, whereas the MNL model without unobserved heterogeneity performs well with the refinance estimates. The MMH clearly dominates the alternative models in sample and out of sample. However, it is sometimes difficult to obtain convergence for the models estimated jointly with mass points.
Seeking a Clearer Picture: Assessing the Appropriate Regulatory Framework for Broadband Video Distribution

This Note examines the appropriate regulatory framework for the distribution of commercial video content over broadband networks. As online video providers such as Netflix and Hulu expand, they are beginning to compete directly with the video services of major cable and telecommunications companies. Frequently, these companies also serve as a customer’s Internet service provider, leaving them in the position of carrying these competitive services over their broadband networks. This conflict has led to calls for regulation that would protect nascent online video services from feared anticompetitive actions by the major providers. In April 2010, against the backdrop of this expanding conflict, the U.S. Court of Appeals for the D.C. Circuit in Comcast Corporation v. FCC dealt a blow to the Federal Communications Commission’s (FCC) ability to regulate in this arena. There, the circuit court invalidated the FCC’s jurisdictional approach to regulating broadband Internet. Although the FCC has subsequently reasserted its jurisdiction over broadband, the fallout from Comcast has rekindled debates as to whether broadband is best governed by proscriptive FCC regulation, or whether oversight of this marketplace should be left to the general antitrust authorities—the Department of Justice and the Federal Trade Commission. This Note discusses the jurisdictional challenges to broadband oversight faced by each agency, and assesses the substantive and procedural merits of FCC and antitrust governance regimes. It then argues that, given the uncertainty regarding its authority, the FCC should abandon its efforts to regulate broadband video distribution in the absence of clear market harms. Finally, this Note proposes that this dynamic and rapidly evolving marketplace should develop outside the bounds of proscriptive regulations, with antitrust serving as a backstop if market intervention proves necessary.
Nonconsensual Pornography and the First Amendment: A Case for a New Unprotected Category of Speech

Nonconsensual pornography, or the distribution of sexually graphic images of individuals without their consent, is not illegal at the federal level, nor is it illegal in the majority of states. Failure to pass laws prohibiting nonconsensual pornography, commonly referred to as “revenge porn,” leaves many victims without recourse. Opponents of legislation regulating revenge porn claim that it cannot be banned because it constitutes speech that is protected by the First Amendment. This article argues that nonconsensual pornography should be considered an unprotected category of speech, which would enable it to be prohibited without triggering First Amendment concerns. The method of regulating revenge porn (i.e., through particular torts or criminal prohibitions) is beyond the scope of this article; instead, it focuses on why this speech should be unprotected, opening the door for legislatures to regulate it as they see fit. Nonconsensual pornography should not be protected by the First Amendment because of its similarities to existing unprotected categories of speech: namely, public disclosure of private fact, defamation, and child pornography. Part I presents the three theories often articulated for why the First Amendment protects speech: to create a marketplace of ideas, facilitate participatory democracy, and promote individual autonomy. Part II explains why certain types of speech are unprotected: because their minimal value towards advancing these free speech goals is outweighed by the significant harm they cause. Part III discusses three current unprotected categories: public disclosure of private fact, defamation, and child pornography. For each, it explains why they have been found to be unprotected - balancing their contribution to promoting free speech values against the harms they cause. Part IV argues for revenge porn as a new unprotected category, first defining the parameters of the category, discussing what the category should encompass in order to ensure it is not overbroad. It then highlights nonconsensual pornography’s low free speech value and analogous harms to the existing three categories — showing it is indistinguishable from speech that has already been deemed unprotected.
Post-prandial effects of high-polyphenolic extra virgin olive oil on endothelial function in adults at risk for type 2 diabetes: A randomized controlled crossover trial.

Abstract Background Effects of olive oil on cardiovascular risk have been controversial. We compared the effects of high-polyphenolic extra virgin olive oil (EVOO) and refined olive oil without polyphenols on endothelial function (EF) in adults at risk for Type 2 diabetes mellitus (T2DM). Methods Randomized, controlled, double-blind, crossover trial of 20 adults (mean age 56.1 years; 10 women, 10 men) at risk for T2DM (i.e., as defined by either prediabetes or metabolic syndrome) assigned to one of two possible sequence permutations of two different single dose treatments (50 mL of high-polyphenolic EVOO or 50 mL of refined olive oil without polyphenols), with 1-week washout. Participants received their olive oils in a smoothie consisting of ½ cup frozen blueberries and 1 cup (8 oz) low-fat vanilla yogurt blended together. Primary outcome measure was EF measured as flow-mediated dilatation. Participants were evaluated before and 2 h after ingestion of their assigned olive oil treatment. Results EVOO acutely improved EF as compared to refined olive oil (1.2 ± 6.5% versus −3.6 ± 3.8%; p = 0.0086). No significant effects on systolic or diastolic blood pressure were observed. Conclusions High-polyphenolic EVOO acutely enhanced EF in the study cohort, whereas refined olive oil did not. Blood pressure effects were not observed. Reports on the vascular effects of olive oil ingestion should specify the characteristics of the oil. Clinical trial registration number NCT04025281
Notions of numerical Iitaka dimension do not coincide

Let $X$ be a smooth projective variety. The Iitaka dimension of a divisor $D$ is an important invariant, but it does not only depend on the numerical class of $D$. However, there are several definitions of ``numerical Iitaka dimension'', depending only on the numerical class. In this note, we show that there exists a pseuodoeffective $\mathbb R$-divisor for which these invariants take different values. The key is the construction of an example of a pseudoeffective $\mathbb R$-divisor $D_+$ for which $h^0(X,\lfloor m D_+ \rfloor+A)$ is bounded above and below by multiples of $m^{3/2}$ for any sufficiently ample $A$.
Nearly Optimal Pseudorandomness From Hardness

Existing proofs that deduce $\text{BPP} =\mathrm{P}$ from circuit lower bounds convert randomized algorithms into deterministic algorithms with a large polynomial slowdown. We convert randomized algorithms into deterministic ones with little slowdown. Specifically, assuming exponential lower bounds against randomized single-valued nondeterministic (SVN) circuits, we convert any randomized algorithm over inputs of length $n$ running in time $t\geq n$ to a deterministic one running in time $t^{2+\alpha}$ for an arbitrarily small constant $\alpha > 0$ . Such a slowdown is nearly optimal, as, under complexity-theoretic assumptions, there are problems with an inherent quadratic derandomization slowdown. We also convert any randomized algorithm that errs rarely into a deterministic algorithm having a similar running time (with pre-processing). The latter derandomization result holds under weaker assumptions, of exponential lower bounds against deterministic SVN circuits. Our results follow from a new, nearly optimal, explicit pseudorandom generator fooling circuits of size s with seed length (1 + α)log s, under the assumption that there exists a function f ∊ E that requires randomized SVN circuits of size at least 2(1−α')n, where. α=O(α'). The construction uses, among other ideas, a new connection between pseudoentropy generators and locally list recoverable codes.
Medium-Term Money Neutrality and the Effective Lower Bound

Conventional wisdom suggests that medium-term money neutrality imposes strong limitations on the effects of monetary policy. The point of this paper is that models with medium- and long-term money neutrality are prone to generate non-existence of equilibria at the effective lower bound (ELB) on interest rates. Non-existence is suggestive of sharp output contractions --- so-called contractionary black holes --- at the ELB. Paradoxically, the case for expansionary monetary policy at the ELB is even stronger in models that feature near money neutrality. The results highlight the benefits of a monetary policy regime in which the central bank temporarily overshoots its inflation target once confronted by the ELB.
Better Together: Online Probabilistic Clique Change Detection in 3D Landmark-Based Maps

Many modern simultaneous localization and mapping (SLAM) techniques rely on sparse landmark-based maps due to their real-time performance. However, these techniques frequently assert that these landmarks are fixed in position over time, known as the static-world assumption. This is rarely, if ever, the case in most real-world environments. Even worse, over long deployments, robots are bound to observe traditionally static landmarks change, for example when an autonomous vehicle encounters a construction zone. This work addresses this challenge, accounting for changes in complex three-dimensional environments with the creation of a probabilistic filter that operates on the features that give rise to landmarks. To accomplish this, landmarks are clustered into cliques and a filter is developed to estimate their persistence jointly among observations of the landmarks in a clique. This filter uses estimated spatial-temporal priors of geometric objects, allowing for dynamic and semi-static objects to be removed from a formally static map. The proposed algorithm is validated in a 3D simulated environment.
Breakup of a long-period comet as the origin of the dinosaur extinction

The origin of the Chicxulub impactor, which is attributed as the cause of the K/T mass extinction event, is an unsolved puzzle. The background impact rates of main-belt asteroids and long-period comets have been previously dismissed as being too low to explain the Chicxulub impact event. Here, we show that a fraction of long-period comets are tidally disrupted after passing close to the Sun, each producing a collection of smaller fragments that cross the orbit of Earth. This population could increase the impact rate of long-period comets capable of producing Chicxulub impact events by an order of magnitude. This new rate would be consistent with the age of the Chicxulub impact crater, thereby providing a satisfactory explanation for the origin of the impactor. Our hypothesis explains the composition of the largest confirmed impact crater in Earth’s history as well as the largest one within the last million years. It predicts a larger proportion of impactors with carbonaceous chondritic compositions than would be expected from meteorite falls of main-belt asteroids.
Time Course of Alterations in Adult Spinal Motoneuron Properties in the SOD1(G93A) Mouse Model of ALS

Although ALS is an adult-onset neurodegenerative disease, motoneuron electrical properties are already altered during embryonic development. Motoneurons must therefore exhibit a remarkable capacity for homeostatic regulation to maintain a normal motor output for most of the life of the patient. In the present paper, we demonstrate how maintaining homeostasis could come at a very high cost. We studied the excitability of spinal motoneurons from young adult SOD1(G93A) mice to end-stage. Initially homeostasis is highly successful in maintaining their overall excitability. This initial success, however, is achieved by pushing some cells far above the normal range of passive and active conductances. As the disease progresses, both passive and active conductances shrink below normal values in the surviving cells. This shrinkage may thus promote survival, implying the previously large values contribute to degeneration. These results support the hypothesis that motoneuronal homeostasis may be “hyper-vigilant” in ALS and a source of accumulating stress. Significance Statement During ALS, motoneurons exhibit a remarkable ability to maintain a normal motor output despite continuous alterations of their electrophysiological properties, up to the point when overt symptoms become apparent. We show that this homeostatic process can sometimes push motoneurons beyond the normal range, which may be causing long-lasting harm.
Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

Sexual selection researchers have traditionally focused on adult sex differences; however, the schedule and pattern of sex-specific ontogeny can provide insights unobtainable from an exclusive focus on adults. Recently, it has been debated whether facial width-to-height ratio (fWHR; bi-zygomatic breadth divided by midface height) is a human secondary sexual characteristic (SSC). Here, we review current evidence, then address this debate using ontogenetic evidence, which has been under-explored in fWHR research. Facial measurements were collected from 3D surface images of males and females aged 3 to 40 (Study 1; US European-descent, n = 2449), and from 2D photographs of males and females aged 7 to 21 (Study 2; Bolivian Tsimane, n = 179), which were used to calculate three fWHR variants (which we call fWHRnasion, fWHRstomion, and fWHRbrow) and two other common facial masculinity ratios (facial width-to-lower-face-height ratio, fWHRlower, and cheekbone prominence). We test whether the observed pattern of facial development exhibits patterns indicative of SSCs, i.e., differential adolescent growth in either male or female facial morphology leading to an adult sex difference. Results showed that only fWHRlower exhibited both adult sex differences as well as the classic pattern of ontogeny for SSCs-greater lower-face growth in male adolescents relative to females. fWHRbrow was significantly wider among both pre- and post-pubertal males in the Bolivian Tsimane sample; post-hoc analyses revealed that the effect was driven by large sex differences in brow height, with females having higher placed brows than males across ages. In both samples, all fWHR measures were inversely associated with age; that is, human facial growth is characterized by greater relative elongation in the mid-face and lower face relative to facial width. This trend continues even into middle adulthood. BMI was also a positive predictor of most of the ratios across ages, with greater BMI associated with wider faces. Researchers collecting data on fWHR should target fWHRlower and fWHRbrow and should control for both age and BMI. Researchers should also compare ratio approaches with multivariate techniques, such as geometric morphometrics, to examine whether the latter have greater utility for understanding the evolution of facial sexual dimorphism.
Private Equity Buyouts and Workplace Safety

This paper presents evidence of a large, persistent decline in establishment-level workplace injury rates after private equity (PE) buyouts of publicly traded U.S. firms. We find that firms experience fewer OSHA safety violations after buyouts and that a larger decline in injury rates is associated with an increased probability of exit via IPO. Employment reductions after buyouts are concentrated in relatively low-injury-risk establishments. Overall, our results suggest that buyouts improve workplace safety and that PE acquirers benefit from this improvement. We explore possible causes of these changes through interviews with executives of companies acquired in buyouts and through cross-sectional analysis.
Reducing the complexity of finite-temperature auxiliary-field quantum Monte Carlo

Abstract The auxiliary-field quantum Monte Carlo (AFMC) method is a powerful and widely used technique for ground-state and finite-temperature simulations of quantum many-body systems. We introduce several algorithmic improvements for finite-temperature AFMC calculations of dilute fermionic systems that reduce the computational complexity of most parts of the algorithm. This is principally achieved by reducing the number of single-particle states that contribute at each configuration of the auxiliary fields to a number that is of the order of the number of fermions. Our methods are applicable for both the canonical and grand-canonical ensembles. We demonstrate the reduced computational complexity of the methods for the homogeneous unitary Fermi gas.
Association of Vitamin D Levels, Race/Ethnicity, and Clinical Characteristics With COVID-19 Test Results.

Importance Deficient (ie, Objective To examine whether COVID-19 test results are associated with differences in vitamin D levels of 30 ng/mL or greater, including for White individuals and for Black individuals. Design, Setting, and Participants This retrospective cohort study was conducted at an academic medical center in Chicago, Illinois. Participants included individuals with data on vitamin D level within 365 days before COVID-19 testing, which was conducted from March 3 to December 30, 2020. Data were analyzed from September 11, 2020, to February 5, 2021. Exposures The last vitamin D level before COVID-19 testing was categorized as less than 20 ng/mL (ie, deficient), 20 to less than 30 ng/mL (ie, insufficient), 30 to less than 40 ng/mL, or 40 ng/mL or greater. Treatment was defined by vitamin D type and dose 14 days before COVID-19 testing and treatment changes after last vitamin D level. Main Outcomes and Measures The main outcome was a positive result for COVID-19 in polymerase chain reaction testing. Multivariable analyses tested whether previously measured vitamin D level was associated with having test results positive for COVID-19 in White individuals and in Black individuals, controlling for months and treatment changes since the vitamin D level was measured, as well as demographic characteristics and comorbidity indicators. Results A total of 4638 individuals (mean [SD] age 52.8 [19.5] years; 3205 [69%] women) had data for a vitamin D level within 1 year before COVID-19 testing, including 2288 (49%) Black individuals, 1999 (43%) White individuals, and 351 individuals (8%) who were another race/ethnicity (eg, Asian, Mideast Indian, >1 race). Stratified by vitamin D level, 1251 individuals (27%) had less than 20 ng/mL, 1267 individuals (27%) had 20 to less than 30 ng/mL, 1023 individuals (22%) had 30 to less than 40 ng/mL, and 1097 individuals (24%) had 40 ng/mL or greater. Lower vitamin D levels were more common in Black individuals ( Conclusions and Relevance In this single-center retrospective cohort study, COVID-19 risk increased among Black individuals with vitamin D level less than 40 ng/mL compared with those with 40 ng/mL or greater and decreased with increasing levels among individuals with levels greater than 30 ng/mL. No significant associations were noted for White individuals. Randomized clinical trials should examine whether increasing vitamin D level to greater than 40 ng/mL affects COVID-19 risk.
Determining the atomic charge of calcium ion requires the information of its coordination geometry in an EF-hand motif

It is challenging to parameterize the force field for calcium ions (Ca2+) in calcium-binding proteins because of their unique coordination chemistry that involves the surrounding atoms required for stability. In this work, we observed a wide variation in Ca2+ binding loop conformations of the Ca2+-binding protein calmodulin, which adopts the most populated ternary structures determined from the molecular dynamics simulations, followed by ab initio quantum mechanical (QM) calculations on all 12 amino acids in the loop that coordinate Ca2+ in aqueous solution. Ca2+ charges were derived by fitting to the electrostatic potential in the context of a classical or polarizable force field (PFF). We discovered that the atomic radius of Ca2+ in conventional force fields is too large for the QM calculation to capture the variation in the coordination geometry of Ca2+ in its ionic form, leading to unphysical charges. Specifically, we found that the fitted atomic charges of Ca2+ in the context of PFF depend on the coordinating geometry of electronegative atoms from the amino acids in the loop. Although nearby water molecules do not influence the atomic charge of Ca2+, they are crucial for compensating for the coordination of Ca2+ due to the conformational flexibility in the EF-hand loop. Our method advances the development of force fields for metal ions and protein binding sites in dynamic environments.
Exploring topology of 1D quasiperiodic metastructures through modulated LEGO resonators

We investigate the dynamics and topology of metastructures with quasiperiodically modulated local resonances. The concept is implemented on a LEGO beam featuring an array of tunable pillar-cone resonators. The versatility of the platform allows the experimental mapping of the Hofstadter-like resonant spectrum of an elastic medium, in the form of a beam waveguide. The non-trivial spectral gaps are classified by evaluating the integrated density of states of the bulk bands, which is experimentally verified through the observation of topological edge states localized at the boundaries. Results also show that the spatial location of the edge states can be varied through the selection of the phase of the resonator's modulation law. The presented results open new pathways for the design of metastructures with functionalities going beyond those encountered in periodic media by exploiting aperiodic patterning of local resonances and suggest a simple, viable platform for the observation of a variety of topological phenomena.
The dynamics and geometry of free group endomorphisms

Abstract We prove that ascending HNN extensions of free groups are word-hyperbolic if and only if they have no Baumslag-Solitar subgroups. This extends the theorem of Brinkmann that free-by-cyclic groups are word-hyperbolic if and only if they have no free abelian subgroups of rank 2. The paper is split into two independent parts: 1) We study the dynamics of injective nonsurjective endomorphisms of free groups. We prove a canonical structure theorem that initializes the development of improved relative train tracks for endomorphisms; this structure theorem is of independent interest since it makes many open questions about injective endomorphisms tractable. 2) As an application of the structure theorem, we are able to (relatively) combine Brinkmann's theorem with our previous work and obtain the main result stated above. In the final section, we further extend the result to HNN extensions of free groups over free factors.
Stasimon Contributes to the Loss of Sensory Synapses and Motor Neuron Death in a Mouse Model of Spinal Muscular Atrophy

Reduced expression of the SMN protein causes spinal muscular atrophy (SMA) - an inherited neurodegenerative disease characterized by multiple synaptic deficits and motor neuron loss. Here, we show that AAV9-mediated delivery of Stasimon - a gene encoding an ER-resident transmembrane protein regulated by SMN - improves motor function in a mouse model of SMA through multiple mechanisms. In proprioceptive neurons of SMA mice, Stasimon overexpression prevents the loss of afferent synapses on motor neurons and enhances sensory-motor neurotransmission. In SMA motor neurons, Stasimon suppresses the neurodegenerative process by selectively reducing phosphorylation but not upregulation of the tumor suppressor p53, both of which are converging events required to trigger neuronal death. We further show that Stasimon deficiency synergizes with SMA-related mechanisms of p53 upregulation to induce phosphorylation of p53. These findings identify Stasimon dysfunction induced by SMN deficiency as an upstream driver of cellular pathways that lead to synaptic loss and motor neuron degeneration, revealing a dual contribution of Stasimon to motor circuit pathology in SMA.
TextGNN: Improving Text Encoder via Graph Neural Network in Sponsored Search

Text encoders based on C-DSSM or transformers have demonstrated strong performance in many Natural Language Processing (NLP) tasks. Low latency variants of these models have also been developed in recent years in order to apply them in the field of sponsored search which has strict computational constraints. However these models are not the panacea to solve all the Natural Language Understanding (NLU) challenges as the pure semantic information in the data is not sufficient to fully identify the user intents. We propose the TextGNN model that naturally extends the strong twin tower structured encoders with the complementary graph information from user historical behaviors, which serves as a natural guide to help us better understand the intents and hence generate better language representations. The model inherits all the benefits of twin tower models such as C-DSSM and TwinBERT so that it can still be used in the low latency environment while achieving a significant performance gain than the strong encoder-only counterpart baseline models in both offline evaluations and online production system. In offline experiments, the model achieves a 0.14% overall increase in ROC-AUC with a 1% increased accuracy for long-tail low-frequency Ads, and in the online A/B testing, the model shows a 2.03% increase in Revenue Per Mille with a 2.32% decrease in Ad defect rate.
Angiomyolipoma with minimal fat on MDCT: Can counts of negative-attenuation pixels aid diagnosis?

OBJECTIVE. The purpose of this study was to determine whether counts of pixels with subzero attenuation on CT scans can aid in the diagnosis of renal angiomyolipoma with minimal fat.MATERIALS AND METHODS. Of 33 angiomyolipomas identified among 719 renal masses resected from 702 patients over 4 years, 15 masses in 15 patients were prospectively diagnosed on the basis of the presence of fat at MDCT. The 18 patients with minimal-fat angiomyolipoma and a matched (age, sex, tumor size) cohort of patients with renal cell carcinoma were included in this study. Three radiologists independently counted the number of pixels with attenuation less than –10, –20, and –30 HU. Receiver operating characteristic analysis of the number of pixels at each cutoff was used to calculate sensitivity, specificity, and positive predictive value with the following criteria: 1, more than 10 pixels less than –20 HU; 2, more than 20 pixels less than –20 HU; 3, more than 5 pixels less than –30 HU.RESULTS. Using criterion 1, reader A id...
Active share: A blessing and a curse

We examine the implications of active mutual fund management across manager skill levels. We find that funds in the highest active share quintile outperform funds in the lowest active share quintile on a risk-adjusted basis. When sorted on both active share and capture ratio, only managers with high skill and high active share experience positive future performance. Funds with high active share and low skill experience negative future risk-adjusted returns, and these funds underperform all funds with low active share. We conclude that only funds with both high active management and high manager skill are preferable to index funds.
Bayesian Modelling of Time-Varying Conditional Heteroscedasticity

Conditional heteroscedastic (CH) models are routinely used to analyze financial datasets. The classical models such as ARCH-GARCH with time-invariant coefficients are often inadequate to describe frequent changes over time due to market variability. However, we can achieve significantly better insight by considering the time-varying analogs of these models. In this paper, we propose a Bayesian approach to the estimation of such models and develop a computationally efficient MCMC algorithm based on Hamiltonian Monte Carlo (HMC) sampling. We also established posterior contraction rates with increasing sample size in terms of the average Hellinger metric. The performance of our method is compared with frequentist estimates and estimates from the time constant analogs. To conclude the paper we obtain time-varying parameter estimates for some popular Forex (currency conversion rate) and stock market datasets.
The t-wise Independence of Substitution-Permutation Networks

Block ciphers such as the Advanced Encryption Standard (Rijndael) are used extensively in practice, yet our understanding of their security continues to be highly incomplete. This paper promotes and continues a research program aimed at proving the security of block ciphers against important and well-studied classes of attacks. In particular, we initiate the study of (almost) t-wise independence of concrete block-cipher construction paradigms such as substitution-permutation networks and key-alternating ciphers. Sufficiently strong (almost) pairwise independence already suffices to resist (truncated) differential attacks and linear cryptanalysis, and hence this is a relevant and meaningful target. Our results are two-fold.
Barnacles and gravity

Theories with more than one vacuum allow quantum transitions between them, which may proceed via bubble nucleation; theories with more than two vacua posses additional decay modes in which the wall of a bubble may further decay. The instantons which mediate such a process have O(3) symmetry (in four dimensions, rather than the usual O(4) symmetry of homogeneous vacuum decay), and have been called ‘barnacles’; previously they have been studied in flat space, in the thin wall limit, and this paper extends the analysis to include gravity. It is found that there are regions of parameter space in which, given an initial bubble, barnacles are the favoured subsequent decay process, and that the inclusion of gravity can enlarge this region. The relation to other heterogeneous vacuum decay scenarios, as well as some of the phenomenological implications of barnacles are briefly discussed.
Motexafin gadolinium, a redox mediator, induces apoptosis in chronic lymphocytic leukemia B-cells and is additive or synergistic with fludarabine

5120 Motexafin gadolinium (MGd, (Xcytrin®) is a tumor-selective redox mediator that oxidizes intracellular reducing metabolites and protein thiols, thereby generating reactive oxygen species (ROS) through a process known as redox cycling. B-cell chronic lymphocytic leukemia (CLL) has elevated levels of the antioxidant ascorbate, and is known to be sensitive to redox stress. Since MGd can generate ROS through oxidation of ascorbate, we reasoned that MGd would be cytotoxic to CLL cells. Mononuclear cells were isolated from the blood of CLL patients (n=15) characterized by Rai Stage, CD38, FISH and immunoglobulin heavy chain variable (Ig VH) mutational status. CLL cells were incubated in vitro over 2-5 days with MGd at concentrations ranging from 0-50 μM. Cytotoxicity was assessed by flow cytometry using annexin V binding/propidium iodide uptake. Accumulation of MGd in CLL cells was demonstrated by flow cytometry using drug fluorescence (>650nm). MGd-induced cytotoxicity was found to be dose-dependent over a range of 2.5 to 50 μM in cells from 11 of 15 CLL patients. CLL cells from 11/15 patients treated with 50 μM MGd and 4/15 patients treated with 10 μM MGd had cytotoxicity levels at least 2 fold above baseline. MGd uptake was similar in sensitive and resistant CLL cells, implying that mechanisms other than uptake are responsible for the differential responses. CLL cells that were sensitive to MGd treatment showed an increase in caspase-3 activity and cleavage of the caspase substrate PARP was found by immunoblot suggesting that MGd induced apoptosis. The induction of apoptosis was found to be exclusive of Rai stage, CLL FISH defects, CD38 expression or Ig VH mutational status. Cells from 5 CLL patients were studied for drug synergy using seven concentrations of MGd (7.5 μm - 50 μM) and the active moiety F-ara-A of fludarabine (0.25 μm-2.0 μM). The cells were treated with each drug individually or both drugs for 48 hours prior to analysis for cytotoxicity. MGd was found to exhibit additive activity (N=4) or synergistic (N=1) effects on CLL B cytotoxicity when combined with fludarabine. Thus, our pre-clinical results reveal that MGd is cytotoxic to CLL cells in vitro through induction of apoptosis. Furthermore, MGd shows additive or synergistic activity when combined with fludarabine. These results support the evaluation of MGd in ongoing CLL clinical trials utilizing this agent alone or in combination with fludarabine.
Bond-selective interferometric scattering microscopy

Interferometric scattering microscopy has been a very promising technology for highly sensitive label-free imaging of a broad spectrum of biological nanoparticles from proteins to viruses in a high-throughput manner. Although it can reveal the specimen's size and shape information, the chemical composition is inaccessible in interferometric measurements. Infrared spectroscopic imaging provides chemical specificity based on inherent chemical bond vibrations of specimens but lacks the ability to image and resolve individual nanoparticles due to long infrared wavelengths. Here, we describe a bond-selective interferometric scattering microscope where the mid-infrared induced photothermal signal is detected by a visible beam in a wide-field common-path interferometry configuration. A thin film layered substrate is utilized to reduce the reflected light and provide a reference field for the interferometric detection of the weakly scattered field. A pulsed mid-IR laser is employed to modulate the interferometric signal. Subsequent demodulation via a virtual lock-in camera offers simultaneous chemical information about tens of micro- or nano-particles. The chemical contrast arises from a minute change in the particle's scattered field in consequence of the vibrational absorption at the target molecule. We characterize the system with sub-wavelength polymer beads and highlight biological applications by chemically imaging several microorganisms including Staphylococcus aureus, Escherichia coli, and Candida albicans. A theoretical framework is established to extend bond-selective interferometric scattering microscopy to a broad range of biological micro- and nano-particles.
Refining Targeted Syntactic Evaluation of Language Models

Targeted syntactic evaluation of subject-verb number agreement in English (TSE) evaluates language models’ syntactic knowledge using hand-crafted minimal pairs of sentences that differ only in the main verb’s conjugation. The method evaluates whether language models rate each grammatical sentence as more likely than its ungrammatical counterpart. We identify two distinct goals for TSE. First, evaluating the systematicity of a language model’s syntactic knowledge: given a sentence, can it conjugate arbitrary verbs correctly? Second, evaluating a model’s likely behavior: given a sentence, does the model concentrate its probability mass on correctly conjugated verbs, even if only on a subset of the possible verbs? We argue that current implementations of TSE do not directly capture either of these goals, and propose new metrics to capture each goal separately. Under our metrics, we find that TSE overestimates systematicity of language models, but that models score up to 40% better on verbs that they predict are likely in context.
Control Protocol Design and Analysis for Unmanned Aircraft System Traffic Management

Due to the rapid development of technologies for small unmanned aircraft systems (sUAS’s), the supply and demand market for sUAS’s is expanding globally. With the great number of sUAS’s ready to fly in civilian airspace, an sUAS aircraft traffic management system that can guarantee the safe and efficient operation of sUAS’s is still absent. In this paper, we propose a control protocol design and analysis method for sUAS traffic management (UTM) which can safely manage a large number of sUAS’s. The benefits of our approach are two-fold: at management level, the effort for monitoring sUAS traffic (authorities) and control/planning for each sUAS (operator/pilot) are both greatly reduced under our framework; and at operational level, the behavior of individual sUAS is guaranteed to follow the restrictions. Mathematical proofs and numerical simulations are presented to demonstrate the proposed method.
Accessibility Measure for Eternal Inflation: Dynamical Criticality and Higgs Metastability

We propose a new measure for eternal inflation, based on search optimization and first-passage statistics. This work builds on the dynamical selection mechanism for vacua based on search optimization proposed recently by the author and Parrikar. The approach is motivated by the possibility that eternal inflation has unfolded for a finite time much shorter than the exponentially long mixing time for the landscape. The proposed accessibility measure assigns greater weight to vacua that are accessed efficiently under time evolution. It is the analogue of the closeness centrality index widely used in network science. The proposed measure enjoys a number of desirable properties. It is independent of initial conditions and oblivious to physical vs comoving weighing of pocket universes. Importantly, the proposed measure makes concrete and testable predictions that are largely independent of anthropic reasoning. Firstly, it favors vacua residing in regions of the landscape with funnel-like topography, akin to the energy landscape of naturally-occurring proteins. Secondly, it favors regions of the landscape that are tuned at dynamical criticality, with vacua having an average lifetime of order the de Sitter Page time. Thus the predicted lifetime of our universe is of order its Page time, ~ 10130 years, which is compatible with Standard Model estimates for electroweak metastability. Relatedly, the supersymmetry breaking scale should be high, at least 1010 GeV. The discovery of beyond-the-Standard Model particles at the Large Hadron Collider or future accelerators, including low-scale supersymmetry, would rule out the possibility that our vacuum lies in an optimal region of the landscape. The present framework suggests a correspondence between the near-criticality of our universe and dynamical critical phenomena on the string landscape.
AMReX: Block-structured adaptive mesh refinement for multiphysics applications:

Block-structured adaptive mesh refinement (AMR) provides the basis for the temporal and spatial discretization strategy for a number of Exascale Computing Project applications in the areas of accel...
Installation Effects on Performance of Multiple Model V/STOL Lift Fans

An experimental program was performed in which the individual performance of multiple VTOL model lift fans was measured. The model tested consisted of three 5.5 in. diameter tip-turbine driven model VTOL lift fans mounted chordwise in a two-dimensional wing to simulate a pod-type array. The performance data provided significant insight into possible thrust variations and losses caused by the presence of cover doors, adjacent fuselage panels, and adjacent fans. The effect of a partial loss of drive air supply (simulated gas generator failure) on fan performance was also investigated. The results of the tests demonstrated that lift fan installation variables and hardware can have a significant effect on the thrust of the individual fans.
A ROSAT observation of the supernova remnant Kes 79

Kes 79 was observed with the ROSAT Position Sensitive Proportional Counter (PSPC) and High Resolution Imager (HRI). Some X-ray emission comes from a faint outer region, well correlated with the outer shell. Most emission is from a bright diffuse inner region where there are also bright radio filaments. The X-ray spectrum is fitted with a thermal model with temperature 1.3 keV. Variations in spectra from different regions arew small. There is no X-ray evidence for an internal neutron star. Remnant characteristics are derived using a simple blast-wave model. The observed X-ray absorption is less than expected. It is possible that the remnant is closer than the published distance of 10 kpc.