cssi/SciSciGPT-SciSciNet huggingface dataset:
The intrinsic dimensionality of graphs

We resolve the following conjecture raised by Levin together with Linial, London, and Rabinovich [Combinatorica, 1995]. For a graph G, let dim(G) be the smallest d such that G occurs as a (not necessarily induced) subgraph of ℤ∞ d , the infinite graph with vertex set ℤ d and an edge (u, v) whenever ∥u − v∥∞ = 1. The growth rate of G, denoted ρ G , is the minimum ρ such that every ball of radius r > 1 in G contains at most r ρ vertices. By simple volume arguments, dim(G) = Ω(ρ G ). Levin conjectured that this lower bound is tight, i.e., that dim(G) = O(ρ G ) for every graph G. Previously, it was unknown whether dim(G) could be bounded above by any function of ρ G . We show that a weaker form of Levin’s conjecture holds by proving that dim(G) = O(ρ G log ρ G ) for any graph G. We disprove, however, the specific bound of the conjecture and show that our upper bound is tight by exhibiting graphs for which dim(G) = Ω(ρ G log ρ G ). For several special families of graphs (e.g., planar graphs), we salvage the strong form, showing that dim(G) = O(ρ G ). Our results extend to a variant of the conjecture for finite-dimensional Euclidean spaces posed by Linial and independently by Benjamini and Schramm.
In memoriam: James Earl Baumgartner (1943–2011)

James Earl Baumgartner (March 23, 1943–December 28, 2011) came of age mathematically during the emergence of forcing as a fundamental technique of set theory, and his seminal research changed the way set theory is done. He made fundamental contributions to the development of forcing, to our understanding of uncountable orders, to the partition calculus, and to large cardinals and their ideals. He promulgated the use of logic such as absoluteness and elementary submodels to solve problems in set theory, he applied his knowledge of set theory to a variety of areas in collaboration with other mathematicians, and he encouraged a community of mathematicians with engaging survey talks, enthusiastic discussions of open problems, and friendly mathematical conversations.
Improved Lower Bounds for Coded Caching

Caching is often used in content delivery networks as a mechanism for reducing network traffic. Recently, the technique of coded caching was introduced whereby coding in the caches and coded transmission signals from the central server were considered. Prior results in this area demonstrate that carefully designing the placement of content in the caches and designing appropriate coded delivery signals from the server allow for a system where the delivery rates can be significantly smaller than conventional schemes. However, matching upper and lower bounds on the transmission rate have not yet been obtained. In this paper, we derive tighter lower bounds on the coded caching rate than were known previously. We demonstrate that this problem can equivalently be posed as a combinatorial problem of optimally labeling the leaves of a directed tree. Our proposed labeling algorithm allows for significantly improved lower bounds on the coded caching rate. Furthermore, we study certain structural properties of our algorithm that allow us to analytically quantify improvements on the rate lower bound for general values of the problem parameters. This allows us to obtain a multiplicative gap of at most four between the achievable rate and our lower bound.
It must be right, GIS told me so! Questioning the infallibility of GIS as a methodological tool

While the benefits of GIS are widely touted among archaeologists today, less attention has been paid to the potential pitfalls and drawbacks of this undeniably important methodological tool. One of the greatest challenges of geospatial modeling is unbalanced data: due to the nature of the archaeological record, we can never assume that the remnants of past behavioral processes we are working with constitute a fully representative sample. Rather, our datasets are reflective of differential social and natural preservation conditions, as well as research biases. Most regional geospatial studies must collate diverse data collected over decades by researchers with varying backgrounds and goals, using assorted spatial scales and levels of technological sophistication. Such factors contribute substantial uncertainty to our models, uncertainty that should be recognized, quantified, and mitigated. If GIS techniques are to continue shifting the way we conduct archaeology and improve our abilities to answer questions regarding past behavior, then we must question the infallibility of GIS as a methodological tool and direct more attention toward developing robust geospatial applications that can meet the idiosyncratic needs of archaeological analysis. This paper explores one example of how such uncertainty investigation can be conducted.
Two-Stage Residual Inclusion Estimation in Health Services Research and Health Economics.

Objectives Empirical analyses in health services research and health economics often require implementation of nonlinear models whose regressors include one or more endogenous variables—regressors that are correlated with the unobserved random component of the model. In such cases, implementation of conventional regression methods that ignore endogeneity will likely produce results that are biased and not causally interpretable. Terza et al. (2008) discuss a relatively simple estimation method that avoids endogeneity bias and is applicable in a wide variety of nonlinear regression contexts. They call this method two-stage residual inclusion (2SRI). In the present paper, I offer a 2SRI how-to guide for practitioners and a step-by-step protocol that can be implemented with any of the popular statistical or econometric software packages. Study Design We introduce the protocol and its Stata implementation in the context of a real data example. Implementation of 2SRI for a very broad class of nonlinear models is then discussed. Additional examples are given. Empirical Application We analyze cigarette smoking as a determinant of infant birthweight using data from Mullahy (1997). Conclusion It is hoped that the discussion will serve as a practical guide to implementation of the 2SRI protocol for applied researchers.
A social cognitive heuristic for adaptive data dissemination in mobile Opportunistic Networks

Abstract It is commonly agreed that data (and data-centric services) will be one of the cornerstones of Future Internet systems. In this context, mobile Opportunistic Networks (OppNets) are one of the key paradigms to efficiently support, in a self-organising and decentralised manner, the growth of data generated by localised interactions between users mobile devices, and between them and nearby smart devices such as IoT nodes. In OppNets scenarios, the spontaneous collaboration among mobile devices is exploited to disseminate data towards interested users. However, the limited resources and knowledge available at each node, and the vast amount of data available in the network, make it difficult to devise efficient schemes to accomplish this task. Recent solutions propose to equip each device with data filtering methods derived from human information processing schemes, known as Cognitive Heuristics. They are very effective methods used by human brains to quickly drop useless information and keep only the most relevant information. Although cognitive-based OppNet solutions proved to be efficient (with limited overheads), they can become less effective when facing dynamic scenarios or situations where nodes cannot fully collaborate with each other, as we show in this paper. One of the reasons is that the solutions proposed so far do not take into account the social structure of the environment where the nodes are moving in. In order to be more effective, the selection of information performed by each node should take into consideration not only the relevance of content for the local device, but also for other devices will encounter in the future due to mobility. To this end, in this paper we propose a social-based data dissemination scheme, based on a cognitive heuristic, known as the Social Circle Heuristic. This heuristic is an evaluation method that exploits the structure of the social environment to make inferences about the relevance of discovered information. We show how the Social Circle Heuristic, coupled with a cognitive-based community detection scheme, can be exploited to design an effective data dissemination algorithm for OppNets. We provide a detailed analysis of the performance of the proposed solution via simulation.
Clinical Research in the Era of Cost Containment

The paranoia associated with attempts to drastically contain the cost of medical care poses a serious threat to further improvements in health care through research. It is assumed that a constant flow of knowledge from the bench to the bedside is not only critical to a high standard of health care, but that it is also cost-effective. In order to fully appreciate this point of view, we must recall that many of our therapies, including those that involve operative intervention, are empiric, and at best, palliative. For example, the most common cancer, lung cancer, is incurable. The second most common gastrointestinal cancer, pancreatic cancer, is not only incurable but difficult to palliate. Trauma, the most common cause of death up to the age of 45, is not only poorly understood, but barely studied. Finally, the complications of atherosclerosis which affect the cardiovascular system occur in epidemic proportions within our aging population. These are only a few of a long list of disabling diseases that deserve further study. I would like to focus my remarks on two questions: (1) Has or will the initiatives towards cost containment in medical care influence biomedical research in an adverse way? and (2) Would an increased investment in clinically directed research result in a lessening of the financial burden shared by society for its health? There is little published evidence that prospective payment of hospitalization by diagnosis-related groups (DRGs), health maintenance organizations (HMO& individual practice associations, preferred provider organizations, for-profit medical corporations, investor-owned hospitals, or other presumed
Supporting medication discontinuation: provider preferences for interventions to facilitate deprescribing.

One approach to prevent adverse drug events is to discontinue (“deprescribe”) medications that are outdated, not indicated, or of limited benefit relative to risk for a particular patient. However, there is little guidance to clinicians about how to integrate the process of deprescribing into the workflow of clinical practice. We sought to determine clinical prescribers’ preferences for interventions that would improve their ability to appropriately and proactively discontinue medications. We conducted a national web-based survey of 2475 prescribers [physicians, nurse practitioners (NP), physician assistants (PA), and clinical pharmacy specialists] practicing in US Veterans Affairs (VA) primary care clinics. One survey question presented 15 potential changes to medication-related practices and respondents ranked their top three choices for changes that would “most improve [their] ability to discontinue medications.” We summed the weighted rankings for each of the 15 response options. Preferences were determined for the whole sample and within subgroups of respondents defined by demographic and background characteristics, medication-relevant experience, and beliefs. Among the 326 respondents who provided rankings, the top choice for a change that would help improve their ability to discontinue medications was “Requiring all medication prescriptions to have an associated ‘indication for use.’” This preference was followed by “Assistance with follow-up of patients as they taper or discontinue medications is performed by another member of the Patient Aligned Care Team (PACT)” and “Increased patient involvement in prescribing decisions.” This combination of options, albeit in varying rank order, was the most commonly selected, with 250 respondents (77%) who answered the question including at least one of these items in their three highest ranked choices, regardless of their demographics, experience, or beliefs. Continued efforts to improve clinicians’ ability to make prescribing decisions, especially around deprescribing, have many potential benefits, including decreased pharmaceutical and health care costs, fewer adverse drug events and complications, and improved patient involvement and satisfaction with their care. Future work, whether as research or quality improvement, should incorporate clinicians’ preferences for interventions, as greater buy-in from front-line staff leads to better adoption of changes.
Effects of Maternal Ritodrine Administration on Neonatal Renal Function

Because of its effects on the cardiovascular and renin-angiotensin systems and on fluid and electrolyte homeostasis, maternal administration of ritodrine to inhibit preterm labor may cause significant alterations in renal function in the newborn infant. We determined inulin clearance, plasma renin activity, urinary arginine vasopressin excretion, and serum and urine electrolyte concentrations and osmolalities at 12 to 36 hours of life and at 6 days of life in 15 infants whose mothers had received ritodrine and in 15 infants whose mothers did not (control infants). At the time of each study, plasma ritodrine concentrations were obtained in the infants whose mothers received ritodrine. The infants whose mothers had received ritodrine had significantly lower inulin clearances and higher plasma renin activity and urinary arginine vasopressin excretion on day 1 but not on day 6. Gestational age was inversely correlated with plasma ritodrine concentration, plasma renin activity, and urinary arginine vasopressin excretion. There were no overt clinical signs of renal failure in any of the infants, and no differences in serum and urine electrolyte values, osmolality, fractional sodium excretion, or urine flow rate were observed between the groups.
Hydropic Cell Variant (Clear Cell Variant) of Wilms’ Tumor

We report an unusual clear cell tumor of the kidney in infancy. The presence in our patient of a discrete mass with foci of primitive nephroblastic cells indicates the neoplastic nature of the clear cells. We discuss its distinction from clear cell sarcomas and carcinomas, and we suggest that this lesion may be inadequately separated from pediatric renal carcinomas in the literature. We recommend the term hydropic cell variant as a less confusing and more accurate descriptive designation.
Association Between Primary Hyperparathyroidism and Previous Irradiation

The association between primary hyperparathyroidism and previous irradiation was investigated in two study groups. Among 36 patients with hyperparathyroidism, 4 (11%) knew of having received radiation therapy. In the second group of 323 patients with a history of radiation exposure and nodular thyroid disease, 4 (1%), thus far, were found to have hyperparathyroidism.
Performance of Yeast Identification Systems. An Analysis of the College of American Pathologists Special Mycology Survey Data

The performance of approximately 400 participants in the CAP Special Mycology Survey in identifying 15 medically important yeasts was analyzed. With nine strains, users of the API 20C system and Uni-Yeast-Tek (UYT) systems performed comparably. With two strains (Trichosporon cutaneum and Candida guilliermondii) the UYT users performed significantly better than API users; with four strains (Cryptococcus albidus, Saccharomyces cerevisiae, and two strains of Candida tropicalis), API users significantly outperformed UYT users. Analysis of biochemical reaction patterns demonstrated, with a few exceptions, good reproducibility among laboratories with both kits. With one exception (melezitose-variable Candida albicans), the few discrepancies in biochemical reactions had little or no influence on the final identification. From this analysis, we conclude that both API and UYT perform acceptably well in routine clinical laboratories when used in conjunction with morphologic observations and, when indicated, supplemented biochemical test.
Process Routes for Low Defect-Density GaN on Various Substrates Employing Pendeo-Epitaxial Growth Techniques

GaN films have been grown on 6H-SiC substrates employing a new form of selective lateral epitaxy, namely pendeo-epitaxy. This technique forces regrowth to start exclusively on sidewalls of GaN seed structures. Both discrete pendeo-epitaxial microstructures and coalesced single crystal layers of GaN have been achieved. SEM and TEM analysis are used to evaluate the morphology of the resulting GaN films. Process routes leading to GaN pendeo-epitaxial growth using silicon substrates have also been achieved and the preliminary results are discussed.
Commentary on: Implied Cost of Equity Capital Estimates as Predictors of Accounting Returns and Stock Returns

The expected rate of equity returns is a central input into various managerial and investment decisions that affect the allocation of scarce resources. Research on capital markets has devoted significant effort to studying how and why expected returns vary over time and across firms. Cochrane (2011) called these questions the central organizing agenda in contemporary asset-pricing research. At the heart of this research agenda lies a longstanding measurement problem: ex-ante expected returns are unobservable and ex-post realized returns are noisy proxies (Campbell, 1991; Vuolteenaho, 2002). Since Botosan (1997), the accounting literature offered a promising solution to this measurement problem: the development of a novel class of expected-return proxies (ERPs), collectively known as the implied cost of equity capital (ICC).
Enhancing Kidney Supply Through Geographic Sharing in the United States

The deceased-donor kidney allocation system suffers from a severe shortage of available organs. We illustrate a mechanism which can increase the supply of cadaveric kidneys in the United States. This supply increase exploits the fact that under the current organ allocation policy, some kidneys remain unprocured in some procurement areas but would be highly sought in other areas. The current kidney allocation policy procures within a Donor Service Area (DSA) and offers these kidneys first to patients in the DSA; if these offers are not accepted, the kidney will be offered within the region (a cluster of DSAs); if these offers are not accepted, the kidney will be offered nationally. A deceased-donor organ is procured if there is the belief that the offered organ will be transplanted (known as “intent”). We conduct an empirical analysis of the donor and recipient data (at the DSA level) which reveals that the intent increases significantly with organ quality, the median waiting time for a transplant, and higher competition. In particular, it shows that lower quality organs are likely to be procured at a higher rate in DSAs with longer waiting times. Motivated by a new kidney allocation system, we conduct a counterfactual study which shows that geographically broader sharing the bottom 15% quality kidneys leads to stronger intent for the organ, thus increasing the supply of procured organs available for transplantation. The expected increase in procured organs ranges from 58 (an increase of 0.4% of all procured kidneys) to 174 (an increase of 1.2%), depending on regional or national sharing. This article is protected by copyright. All rights reserved.
Replication of early and recent Zika virus isolates throughout mouse brain development

Fetal infection with Zika virus (ZIKV) can lead to congenital Zika virus syndrome (cZVS), which includes cortical malformations and microcephaly. The aspects of cortical development that are affected during virus infection are unknown. Using organotypic brain slice cultures generated from embryonic mice of various ages, sites of ZIKV replication including the neocortical proliferative zone and radial columns, as well as the developing midbrain, were identified. The infected radial units are surrounded by uninfected cells undergoing apoptosis, suggesting that programmed cell death may limit viral dissemination in the brain and may constrain virus-associated injury. Therefore, a critical aspect of ZIKV-induced neuropathology may be defined by death of uninfected cells. All ZIKV isolates assayed replicated efficiently in early and midgestation cultures, and two isolates examined replicated in late-gestation tissue. Alteration of neocortical cytoarchitecture, such as disruption of the highly elongated basal processes of the radial glial progenitor cells and impairment of postmitotic neuronal migration, were also observed. These data suggest that all lineages of ZIKV tested are neurotropic, and that ZIKV infection interferes with multiple aspects of neurodevelopment that contribute to the complexity of cZVS.
U.S. War Powers and the Potential Benefits of Comparativism

There is no issue of foreign relations law more important than the allocation of authority over the use of military force. This issue is especially important for the United States given the frequency with which it is involved in military activities abroad. Yet there is significant uncertainty and debate in the United States over this issue — in particular, over whether and to what extent military actions must be authorized by Congress. Because U.S. courts in the modern era have generally declined to review the legality of military actions, disputes over this issue have had to be resolved, as a practical matter, through the political process. For those who believe that it is important to have legislative involvement in decisions to use force, the political process has not proven to be satisfactory: presidents have often used military force without obtaining congressional approval, and Congress generally has done little to resist such presidential unilateralism. The United States is not the only country to struggle with regulating the domestic authority to use military force. This issue of foreign relations law is common to constitutional democracies, and nations vary substantially in how they have addressed the issue. Whether and to what extent such comparative materials should inform the interpretation or revision of U.S. law presents a complicated set of questions that are affected in part by one’s legal methodology and also by how the comparative materials are being invoked. This Chapter begins by describing the exercise of war powers authority in the United States, both before and after World War II, as well as some of the limitations on congressional and judicial checks on presidential uses of military force. It then considers the potential value of studying the war powers law and practice of other countries, as well some of the reasons to be cautious about relying on such comparative materials.
The Effect of Housing Demolitions on Crime in Buffalo, New York:

Objectives:From 2010 through 2015, the city of Buffalo demolished over 2,000 residences. This study examines whether those demolitions resulted in crime reductions.Methods:Analysis was conducted at...
Ensemble Sampling

Thompson sampling has emerged as an effective heuristic for a broad range of online decision problems. In its basic form, the algorithm requires computing and sampling from a posterior distribution over models, which is tractable only for simple special cases. This paper develops ensemble sampling, which aims to approximate Thompson sampling while maintaining tractability even in the face of complex models such as neural networks. Ensemble sampling dramatically expands on the range of applications for which Thompson sampling is viable. We establish a theoretical basis that supports the approach and present computational results that offer further insight.
Appointments and attrition: time and executive disadvantage in the appointments process

While the importance of political appointments is a matter of consensus, theorists and empiricists generally focus on different considerations, such as ideology and confirmation duration, respectively. More recently, there have been efforts to integrate empirical and theoretical scholarship but, to date, no empirical analysis assesses theoretical expectations about the relationship between temporal concerns and nominee ideologies. We fill this gap by examining theoretical predictions and related expectations about how the passage of time affects the President’s choices of nominees. We find that executives are disadvantaged as days pass and Presidents propose nominees with whom they are less ideologically compatible over time.
Gaining Acceptance by Informing the People? Public Knowledge, Attitudes, and Acceptance of Transportation Policies:

We examine the connection between public knowledge and attitudes in the context of urban transportation policies. We categorize policy knowledge into received, subjective, and reasoned knowledge, a...
Hybrid sulfur flowsheets using PEM electrolysis and a bayonet decomposition reactor

Abstract A conceptual design is presented for a hybrid sulfur process for the production of hydrogen using a high-temperature nuclear heat source to split water. The process combines proton exchange membrane-based SO2-depolarized electrolyzer technology being developed at Savannah River National Laboratory with silicon carbide bayonet decomposition reactor technology being developed at Sandia National Laboratories. Both are part of the US DOE Nuclear Hydrogen Initiative. The flowsheet otherwise uses only proven chemical process components. Electrolyzer product is concentrated from 50 wt% sulfuric acid to 75 wt% via recuperative vacuum distillation. Pinch analysis is used to predict the high-temperature heat requirement for sulfuric acid decomposition. An Aspen Plus™ model of the flowsheet indicates 340.3 kJ high-temperature heat, 75.5 kJ low-temperature heat, 1.31 kJ low-pressure steam, and 120.9 kJ electric power are consumed per mole of H2 product, giving an LHV efficiency of 35.3% (41.7% HHV efficiency) if electric power is available at a conversion efficiency of 45%.
Sticky prices versus sticky information: Does it matter for policy paradoxes?

Abstract This paper shows that under a strict inflation targeting regime, the government spending multiplier at the zero lower bound (ZLB) is larger under sticky information than under sticky prices. Similarly, well known paradoxes, e.g., the paradox of toil and the paradox of flexibility become more severe under sticky information. For the case of sticky information it is important to assume that the fiscal policy intervention coincides with the duration of zero interest rates, while such a distinction is less important for sticky prices. We unify and clarify results that may appear to contradict each other in the literature.
Relative Measurement Theory the Unification of Experimental and Theoretical Measurements

Abstract The discontinuous, non-causal and instantaneous changes due to a measurement that appear in quantum mechanics (QM) theory are not consistent with a classical understanding of physical reality, but are completely confirmed by experiments. Relative measurement theory explains why. This paper presents the first formal development of an experimental measurement which includes the uncertainty due to calibration and resolution. The uncertainty due to calibration and resolution, previously considered experimental artifacts, is shown to be equal to the uncertainty that appears in QM theory and experiment. When the calibration to a reference and resolution effects are considered, all the QM measurement discontinuities are consistent with classical explanations.
Moral Hazard Misconceptions: The Case of the Greenspan Put

Policy discussions on financial regulation tend to assume that whenever a corrective policy is used ex post to ameliorate the effects of a crisis, there are negative side effects in terms of moral hazard ex ante. This paper shows that this is not a general theoretical prediction, focusing on the case of monetary policy interventions ex post. In particular, we show that if the central bank does not intervene by monetary easing following a crisis, an aggregate demand externality makes borrowing ex ante inefficient. If instead the central bank follows the optimal discretionary policy and intervenes to stabilize asset prices and real activity, we show examples in which the aggregate demand externality disappears, reducing the need for ex ante intervention.
How the physicality of space affects how we think about time

Time is an abstract concept that may be better understood when mapped onto space. For English speakers, typically a timeline is used that runs horizontally from left (past) to right (future) (Boroditsky, Fuhrman, & McCormick, 2011) and can be separated into regions, past and future. However, it is unclear from prior research how these regions along the timeline are differentiated. In addition, although for English speakers time is typically thought of in terms of a left–right axis, gestures and metaphors that conceptualize the past as behind and the future as ahead are prevalent, implicating the use of a front–back axis. In three experiments, participants made temporal judgments of pictures while holding their hands in various positions around their bodies, to assess whether the body or hands or both are used as anchors to differentiate regions and whether the front–back axis can be used as a timeline. In Experiment 1 we found independent influences of the body and the hands in anchoring the left–right axis. In Experiment 2 we found support for the use of the front–back axis to map time, with independent influences of the body and the hands in anchoring this axis as well. In Experiment 3 we demonstrated that the timeline must be configured in a way that is consistent with underlying conceptualizations of time, by showing that the above–below axis is not used for English speakers. Together, these results indicate that time is mapped onto space, with this mapping being constrained by underlying conceptualizations of time.
Exploiting MIT Shocks in Heterogeneous-Agent Economies: The Impulse Response as a Numerical Derivative

Abstract We propose a new method for computing equilibria in heterogeneous-agent models with aggregate uncertainty. The idea relies on an assumption that linearization offers a good approximation; we share this assumption with existing linearization methods. However, unlike those methods, the approach here does not rely on direct derivation of first-order Taylor terms. It also does not use recursive methods, whereby aggregates and prices would be expressed as linear functions of the state, usually a very high-dimensional object (such as the wealth distribution). Rather, we rely merely on solving nonlinearly for a deterministic transition path: we study the equilibrium response to a single, small “MIT shock” carefully. We then regard this impulse response path as a numerical derivative in sequence space and hence provide our linearized solution directly using this path. The method can easily be extended to the case of many shocks and computation time rises linearly in the number of shocks. We also propose a set of checks on whether linearization is a good approximation. We assert that our method is the simplest and most transparent linearization technique among currently known methods. The key numerical tool required to implement it is value-function iteration, using a very limited set of state variables. This article is part of a Special Issue entitled “Fiscal and Monetary Policies”.
Verifying chemical reaction network implementations: A bisimulation approach

Efforts in programming DNA and other biological molecules have recently focused on general schemes to physically implement arbitrary Chemical Reaction Networks. Errors in some of the proposed schemes have driven a desire for formal verification methods. We show that by interpreting each implementation species as a set of formal species, the concept of weak bisimulation can be adapted to CRNs in a way that agrees with an intuitive notion of a correct implementation. We give examples of how to use bisimulation to prove the correctness of an implementation or detect subtle problems. We examine the complexity of finding a valid interpretation between two CRNs if one exists, and that of checking whether an interpretation is valid. We show that both are PSPACE-complete in the general case, but are NP-complete and polynomial-time respectively under an assumption that holds in many practical cases. We give algorithms for both of those problems.
Can and Should the New Third-Party Litigation Financing Come to Class Actions?

In the United States, there has been tremendous growth in a form of third-party litigation nancing where investors buy pieces of lawsuits from plaintiffs. Many scholars believe that this new nancing helps to balance the risk tolerance of plaintiffs and defendants and thereby facilitates the resolution of litigation in a way that more closely tracks the goals of the substantive law. In this Article, I ask whether these risk-balancing virtues of claim investing carry over into class action cases. This is a question that has not yet been addressed by scholars because many think it is not possible for nanciers to buy pieces of class action lawsuits in the United States. But I show that such investments are neither impractical nor unethical; indeed, it appears that they are already here. It is therefore worth considering whether the investments confer the same social bene ts they do in other cases. I argue that although class members do not need a risk transfer device in class action cases because they are almost always risk-neutral in light of their small losses, their lawyers do need such a device. Although this does not necessarily mean that claim investing is socially desirable overall in class actions, the social costs that have thus far been identi ed with claim investing seem modest compared to the bene ts.
Metalevel algorithms for variant satisfiability

Abstract Variant satisfiability is a theory-generic algorithm to decide quantifier-free satisfiability in an initial algebra T Σ / E when the theory ( Σ , E ) has the finite variant property and its constructors satisfy a compactness condition. This paper: (i) gives a precise definition of several meta-level sub-algorithms needed for variant satisfiability; (ii) proves them correct; and (iii) presents a reflective implementation of variant satisfiability checking using these sub-algorithms in Maude 2.7.1.
Evaluating the Flipped Classroom: A Randomized Controlled Trial.

ABSTRACTDespite recent interest in flipped classrooms, rigorous research evaluating their effectiveness is sparse. In this study, the authors implement a randomized controlled trial to evaluate the effect of a flipped classroom technique relative to a traditional lecture in an introductory undergraduate econometrics course. Random assignment enables the analysis to eliminate other potential explanations of performance differences between the flipped and traditional classrooms, while assignment of experimental condition by section and lesson enables improved statistical precision. The authors find that the flipped classroom increases scores on medium-term, high-stakes assessments by 0.16 standard deviation, with similar long-term effects for high-performing students. Estimated impacts are robust to alternative specifications accounting for possible spillover effects arising from the experimental design.
Identifying and treating the prodromal phases of bipolar disorder and schizophrenia.

The goal of this paper is to review recent research on the identification and treatment of prodromal periods that precede bipolar and psychotic disorders. We also sought to provide information about current best clinical practices for prodromal youth. Research in the areas of identifying prodromal periods has rapidly advanced. Calculators that can predict risk are now available for use during both bipolar and psychotic disorder prodromes. Cognitive behavior therapies have emerged as the gold standard psychosocial interventions for the psychosis prodrome, while several other types of therapies hold promise for treatment during the bipolar prodrome. Due to safety and efficacy concerns, pharmacologic treatments are not currently recommended during either prodromal periods. While additional research is needed to develop useful clinical tools to screen and diagnose during prodromal phases, existing literature has identified constellations of symptoms that can be reliably identified in research settings. Specialized psychotherapies are currently recommended to treat prodromal symptoms in clinical settings. They may also be useful to curtail future episodes, although further research is needed.
Semantic sentence embeddings for paraphrasing and text summarization

This paper introduces a sentence to vector encoding framework suitable for advanced natural language processing. Our latent representation is shown to encode sentences with common semantic information with similar vector representations. The vector representation is extracted from an encoderdecoder model which is trained on sentence paraphrase pairs. We demonstrate the application of the sentence representations for two different tasks — sentence paraphrasing and paragraph summarization, making it attractive for commonly used recurrent frameworks that process text. Experimental results help gain insight how vector representations are suitable for advanced language embedding.
Evidence of directional price discrimination in the U.S. airline industry

Abstract This paper explores possible determinants that may affect an airline’s decision to charge passengers different roundtrip fares depending on trip origin, a case of directional price discrimination. Such fare differences cannot be the result of differences in cost, as the cost of flying a roundtrip passenger does not significantly differ depending on direction. It is argued that directional fare differences result from airlines recognizing that passenger price elasticities differ between route endpoints. A price discriminating airline will then charge a higher roundtrip fare at the endpoint where the passenger price elasticity of demand is comparatively lower. Evidence is found suggesting that airlines do use differences in income to price discriminate when setting roundtrip fares. Fares are found to be $0.18-$0.43 higher on average for each $1000 difference in average per capita income between origin and destination metro areas. This finding is sensible assuming that higher incomes reduce the price elasticity of demand for air travel, with richer passengers being less sensitive to the cost of travel.
Bespoke Processors for Applications with Ultra-Low Area and Power Constraints

This article makes the case for bespoke processor design, an automated approach that tailors a general-purpose processor IP to a target application by removing all gates from the design that can never be used by the application. The resulting processors are more area- and energy-efficient without sacrificing performance.
Prediction of Ischemic Events after Percutaneous Coronary Intervention: Thrombelastography Profiles and Factor XIIIa Activity

Background High plasma fibrin clot strength (MA) measured by thrombelastography (TEG) is associated with increased risk of cardiac events after percutaneous coronary interventions (PCIs). Factor XIIIa (FXIIIa) cross-links soluble fibrin, shortens clot formation time (TEG-K), and increases final clot strength (MA). Methods We analyzed platelet-poor plasma from patients with previous PCI. Kaolin-activated TEG (R, K, MA) in citrate platelet-poor plasma and FXIIIa were measured (n = 257). Combined primary endpoint was defined as recurrent myocardial infarction (MI) or cardiovascular death (CVD). Relationship of FXIIIa and TEG measurements on cardiac risk was explored. Results FXIIIa correlated with TEG-MA (p = 0.002) and inversely with TEG-K (p Conclusion FXIIIa is associated with higher plasma TEG-MA and low TEG-K. High FXIIIa activity is associated with a modest increase in cardiovascular risk after PCI, but is less sensitive and specific than TEG-MA. Addition of FXIIIa does not provide additional risk stratification beyond risk associated with high fibrin clot strength phenotype measured by TEG.
Relative plausibility and its critics

Within legal scholarship there is a tendency to use (perhaps overuse) “paradigm shift” in ways far removed from the process famously described by Thomas Kuhn. Within the field of evidence, however,...
Spt6 Is Required for the Fidelity of Promoter Selection

Summary Spt6 is a conserved factor that controls transcription and chromatin structure across the genome. Although Spt6 is viewed as an elongation factor, spt6 mutations in Saccharomyces cerevisiae allow elevated levels of transcripts from within coding regions, suggesting that Spt6 also controls initiation. To address the requirements for Spt6 in transcription and chromatin structure, we have combined four genome-wide approaches. Our results demonstrate that Spt6 represses transcription initiation at thousands of intragenic promoters. We characterize these intragenic promoters and find sequence features conserved with genic promoters. Finally, we show that Spt6 also regulates transcription initiation at most genic promoters and propose a model of initiation site competition to account for this. Together, our results demonstrate that Spt6 controls the fidelity of transcription initiation throughout the genome.
DOES PRENATAL WIC PARTICIPATION IMPROVE CHILD OUTCOMES

A large body of literature documents positive effects of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on birth outcomes, and separately connects health at birth and future outcomes. But little research investigates the link between prenatal WIC participation and childhood outcomes. We explore this question using a unique data set from South Carolina that links administrative birth, Medicaid, and education records. We find that relative to their siblings, prenatal WIC participants have a lower incidence of ADHD (attention-deficit/hyperactivity disorder) and other common childhood mental health conditions and a lower incidence of grade repetition. These findings demonstrate that a "WIC start" results in persistent improvements in child outcomes across a range of domains.
Metric Sublinear Algorithms via Linear Sampling

We provide a new technique to design fast approximation algorithms for graph problems where the points of the graph lie in a metric space. Specifically, we present a sampling approach for such metric graphs that, using a sublinear number of edge weight queries, provides a linear sampling, where each edge is (roughly speaking) sampled proportionally to its weight. For several natural problems, such as densest subgraph and max cut, we show that by sparsifying the graph using this sampling process, we can run a suitable approximation algorithm on the sparsified graph and the result remains a good approximation for the original problem. Our results have several interesting implications, such as providing the first sublinear time approximation algorithm for densest subgraph in a metric space, and improving the running time of estimating the average distance.
Sox4 Promotes Atoh1-Independent Intestinal Secretory Differentiation Toward Tuft and Enteroendocrine Fates.

Background & Aims The intestinal epithelium is maintained by intestinal stem cells (ISCs), which produce postmitotic absorptive and secretory epithelial cells. Initial fate specification toward enteroendocrine, goblet, and Paneth cell lineages requires the transcription factor Atoh1, which regulates differentiation of the secretory cell lineage. However, less is known about the origin of tuft cells, which participate in type II immune responses to parasite infections and appear to differentiate independently of Atoh1. We investigated the role of Sox4 in ISC differentiation. Methods We performed experiments in mice with intestinal epithelial-specific disruption of Sox4 (Sox4fl/fl:vilCre; SOX4 conditional knockout [cKO]) and mice without disruption of Sox4 (control mice). Crypt- and single-cell–derived organoids were used in assays to measure proliferation and ISC potency. Lineage allocation and gene expression changes were studied by immunofluorescence, real-time quantitative polymerase chain reaction, and RNA-seq analyses. Intestinal organoids were incubated with the type 2 cytokine interleukin 13 and gene expression was analyzed. Mice were infected with the helminth Nippostrongylus brasiliensis and intestinal tissues were collected 7 days later for analysis. Intestinal tissues collected from mice that express green fluorescent protein regulated by the Atoh1 promoter (Atoh1GFP mice) and single-cell RNA-seq analysis were used to identify cells that coexpress Sox4 and Atoh1. We generated SOX4-inducible intestinal organoids derived from Atoh1fl/fl:vilCreER (ATOH1 inducible knockout) mice and assessed differentiation. Results Sox4cKO mice had impaired ISC function and secretory differentiation, resulting in decreased numbers of tuft and enteroendocrine cells. In control mice, numbers of SOX4+ cells increased significantly after helminth infection, coincident with tuft cell hyperplasia. Sox4 was activated by interleukin 13 in control organoids; SOX4cKO mice had impaired tuft cell hyperplasia and parasite clearance after infection with helminths. In single-cell RNA-seq analysis, Sox4+/Atoh1− cells were enriched for ISC, progenitor, and tuft cell genes; 12.5% of Sox4-expressing cells coexpressed Atoh1 and were enriched for enteroendocrine genes. In organoids, overexpression of Sox4 was sufficient to induce differentiation of tuft and enteroendocrine cells—even in the absence of Atoh1. Conclusions We found Sox4 promoted tuft and enteroendocrine cell lineage allocation independently of Atoh1. These results challenge the longstanding model in which Atoh1 is the sole regulator of secretory differentiation in the intestine and are relevant for understanding epithelial responses to parasitic infection.
Boundary lipids of the nicotinic acetylcholine receptor: Spontaneous partitioning via coarse-grained molecular dynamics simulation.

Abstract Reconstituted nicotinic acetylcholine receptors (nAChRs) exhibit significant gain-of-function upon addition of cholesterol to reconstitution mixtures, and cholesterol affects the organization of nAChRs within domain-forming membranes, but whether nAChR partitions to cholesterol-rich liquid-ordered (“raft” or lo) domains or cholesterol-poor liquid-disordered (ldo) domains is unknown. We use coarse-grained molecular dynamics simulations to observe spontaneous interactions of cholesterol, saturated lipids, and polyunsaturated (PUFA) lipids with nAChRs. In binary Dipalmitoylphosphatidylcholine:Cholesterol (DPPC:CHOL) mixtures, both CHOL and DPPC acyl chains were observed spontaneously entering deep “non-annular” cavities in the nAChR TMD, particularly at the subunit interface and the β subunit center, facilitated by the low amino acid density in the cryo-EM structure of nAChR in a native membrane. Cholesterol was highly enriched in the annulus around the TMD, but this effect extended over (at most) 5–10 A. In domain-forming ternary mixtures containing PUFAs, the presence of a single receptor did not significantly affect the likelihood of domain formation. nAChR partitioned to any cholesterol-poor ldo domain that was present, regardless of whether the ldo or lo domain lipids had PC or PE headgroups. Enrichment of PUFAs among boundary lipids was positively correlated with their propensity for demixing from cholesterol-rich phases. Long n-3 chains (tested here with Docosahexaenoic Acid, DHA) were highly enriched in annular and non-annular embedded sites, partially displacing cholesterol and completely displacing DPPC, and occupying sites even deeper within the bundle. Shorter n-6 chains were far less effective at displacing cholesterol from non-annular sites.