cssi/SciSciGPT-SciSciNet huggingface dataset:
African-American Grandmothers: Does the Gender-Entrapment Theory Apply? Essay Response to Professor Beth Richie

Many African-American grandmothers are entrapped by the cycle of incarceration in poor black communities. This Essay explores whether the social and economic conditions that compel battered women to commit crimes also impact their mothers - who end up raising the children they leave behind. Professor Beth Richie's theory of gender entrapment as described in her book, “Compelled to Crime,” is not limited to incarcerated women who have been victims of domestic violence. African-American grandmothers who take on the role of kinship caregivers for their grandchildren are also entrapped by a complex interplay of race, gender, and class, making them vulnerable to poverty, generational diseases, and shorter life spans. This Essay concludes by identifying potential policy and legal reforms that seek to intervene in the state's management of black family life by empowering generations of black women with emotional and economic resources.
Effects of Weight on Children's Educational Achievement

Abstract In this paper, we investigate the association between weight and children's educational achievement, as measured by scores on Peabody Individual Achievement Tests in math and reading, and grade attainment. Data for the study came from the 1979 cohort of the National Longitudinal Survey of Youth (NLSY), which contains a large, national sample of children between the ages of 5 and 12 between 1986 and 2004. We obtained estimates of the association between weight and achievement using several regression model specifications that controlled for a variety of observed characteristics of the child and his or her mother, and time-invariant characteristics of the child. Our results suggest that, in general, children who are overweight or obese have achievement test scores that are about the same as children with average weight.
BUY-IT-NOW OR TAKE-A-CHANCE: PRICE DISCRIMINATION THROUGH RANDOMIZED AUCTIONS

Increasingly detailed consumer information makes sophisticated price discrimination possible. At fine levels of aggregation, demand may not obey standard regularity conditions. We propose a new randomized sales mechanism for such environments. Bidders can “buy-it-now” at a posted price, or “take-a-chance” in an auction where the top d > 1 bidders are equally likely to win. The randomized allocation incentivizes high-valuation bidders to buy-it-now. We analyze equilibrium behavior and apply our analysis to advertiser bidding data from Microsoft Advertising Exchange. In counterfactual simulations, our mechanism increases revenue by 4.4% and consumer surplus by 14.5% compared to an optimal second-price auction. This paper was accepted by Assaf Zeevi, stochastic models and simulation.
Appellate Review of Social Facts in Constitutional Rights Cases

There is great confusion among scholars and courts about whether and when appellate courts may, or must, defer to trial courts’ findings of social fact in constitutional rights cases. The Supreme Court has never directly decided the question and indeed has addressed it only once, in passing. A common assumption, promoted by scholars and adopted as binding by some circuits, is that the deferential, clearly-erroneous standard of Federal Rule of Civil Procedure 52(a)(6) does not apply to social facts. This article challenges that assumption. There is nothing in the text of the rule that supports this conclusion. Moreover, except in certain, readily identifiable circumstances, it makes sense for appellate courts to defer to trial courts’ findings of social fact. Federal bench trials are better suited than the appellate process to vetting social facts when laws are challenged as violating constitutional rights. There is rarely a reason, other than rhetorical, for appellate courts to venture beyond the trial record to determine key social facts in such cases. In the instances when such facts are missing, a remand for further factfinding at the trial level will often be workable and appropriate. Since a court’s findings of social fact can determine whether constitutional rights claims succeed or fail, it is crucial to achieve a clearer understanding of the roles and respective authority of appellate and trial courts in factfinding in constitutional rights cases. This article sorts out the tangle of rules and precedents concerning appellate review of trial court factfinding in the constitutional rights context. It then proposes a framework for assessing whether and when appellate courts should defer to trial courts’ findings of social fact in constitutional rights cases.
Conservation without nature: the trouble with in situ versus ex situ conservation

Abstract Although understudied in academia and mostly unheard of by the general public, the in situ / ex situ dichotomy has shaped—and still very much shapes—the development of the nature conservation movement and its institutional alliances in the last few decades. Latin for “in” and “out” of place, the in / ex situ dichotomy often stands for the seemingly less scientific dichotomy between wild nature and captivity. Drawing on ethnographic engagements with zoo professionals and wildlife managers, this article explores the evolution of the in situ / ex situ dyad in nature conservation, which traverses the worlds of dead and live matter, artificilia and naturalia, and the seemingly disconnected institutions of museums and zoos, game parks, and nature reserves. Drawing on animal and relational geography, the article suggests that the assumptions underlying the in situ versus ex situ divide in conservation are anachronistic, romantic, and unsustainable and that they are incompatible with ideas of naturecultures and multinatures and with non-traditional perceptions of space. Eventually, this grounded study of conservation discourses and practices highlights the possibility of conservation management without nature.
Litigating Secrets: Comparative Perspectives on the State Secrets Privilege

The Article considers the history and use of the state secrets privilege in the United States and the ongoing congressional efforts to reform the use of the privilege. Although numerous articles have addressed the application of the state secrets privilege in the United States, this Article breaks new ground by examining the history and use of the privilege in other nations which confront serious national security threats. This Article considers the modern application the privilege in Scotland, England, Israel and India—an analysis which contextualizes both the current use of the U.S. privilege and the efforts at legislative reform. Such comparative analysis is necessary to fully understand the transnational implications of the U.S. application of the state secrets privilege, which have recently come to light in litigation involving both the United States and England. This Article concludes that domestic reform efforts continue to be necessary to achieve an appropriate application of the privilege which balances national security with the need to preserve the rule of law, individual rights, liberty interests and government accountability. The Article further suggests that reforms should explicitly account for alleged human rights abuses by the government in determining whether a claim of privilege should be upheld. 2009] Litigating Secrets [xx
Credit Constraints, Heterogeneous Firms, and International Trade

Financial market imperfections severely restrict international trade ‡ows because exporters require external capital. This paper identi…es and quanti…es the three mechanisms through which credit constraints aect trade: the selection of hetero- geneous …rms into domestic production, the selection of domestic manufacturers into exporting, and the level of …rm exports. I incorporate …nancial frictions into a heterogeneous-…rm model and apply it to aggregate trade data for a large panel of countries. I establish causality by exploiting the variation in …nancial development across countries and the variation in …nancial vulnerability across sectors. About 20%-25% of the impact of credit constraints on trade is driven by reductions in total output. Of the additional, trade-speci…c eect, one third re‡ects limited …rm entry into exporting, while two thirds are due to contractions in exporters'sales. Finan- cially developed economies export more in …nancially vulnerable sectors because they enter more markets, ship more products to each destination, and sell more of each product. These results have important policy implications for less developed nations that rely on exports for economic growth but suer from weak …nancial institutions.
CROSS-LISTING AND CORPORATE GOVERNANCE: BONDING OR AVOIDING?

In their seminal survey of corporate governance, Shleifer and Vishny distill the issue into a blunt question: “How do [the suppliers of finance] make sure that managers do not steal the capital they supply or invest it in bad projects?” The Enron/Arthur Andersen debacle and the ensuing waves of scandal vividly proved that American investors may face this question in the most acute form. Yet even today, many would argue that in a global comparison, American securities markets provide public investors with a more hospitable and protective environment than most other markets around the world. American markets still fare better in terms of the legal rules governing them, the legal professionals that work to enforce the regime, and a sophisticated court system that provides the necessary infrastructure for a well-functioning corporate governance system. The 2002 wave of scandal tarnished the reputation of the American market, but has not eroded it completely. The American governance environment is out for rent. Foreign firms wishing to enjoy the benefits of being subject to the American regime can readily do so by cross-listing their securities on an American market—even without raising capital in the United States. The idea that foreign firms actually engage in cross-listing with a view towards improving their corporate governance is often
Deconvolution of intermixed redox processes in Ni-based cation-disordered Li-excess cathodes

Cation-disordered rock-salt transition-metal oxides and oxyfluorides (DRX) have emerged as promising cathode materials for Li-ion batteries due to their potential to reach high energy densities and accommodate diverse, lower cost transition-metal chemistries compared to conventional layered oxide materials. However, the intricate local coordination environment in DRX also results in complex electrochemical electron transfer involving parallel mechanisms of transition-metal (TM) redox and oxygen (anionic) redox. Without decoupled and quantitative information of these intermixed redox processes, the origin of irreversibility, voltage hysteresis, and capacity fading is obscured, impeding the development of strategies to address these issues. Here we deconvolute the mixed redox processes in a Ni-based DRX, Li1.15Ni0.45Ti0.3Mo0.1O1.85F0.15, by combining 18O isotopic enrichment, differential electrochemical mass spectrometry (DEMS), and ex situ acid titration. The summation of TM-redox and oxygen-redox capacities measured through our approach agrees with the net electron transfer measured by the potentiostat. This study reveals much less Ni oxidation efficiency (59.5%) than its initially designed efficiency (100%) due to competition of oxygen redox, which can occur at potentials as low as 4.1 V (vs. Li/Li+). We propose that the chemical approach presented in this work and its future extension can resolve and quantify various mixed redox processes in different DRX, which allows clear correlations among material design, deconvoluted redox capacities, and battery performance.
On Uniform Exponential Ergodicity of Markovian Multiclass Many-Server Queues in the Halfin–Whitt Regime

We study ergodic properties of Markovian multiclass many-server queues that are uniform over scheduling policies and the size of the system. The system is heavily loaded in the Halfin–Whitt regime,...
Immune Complex Vaccine Strategies to Combat HIV-1 and Other Infectious Diseases

Immune complexes (ICs) made of antibody-bound antigens exhibit immunomodulatory activities exploitable in a vaccination strategy to optimize vaccine efficacy. The modulatory effects of ICs are typically attributed to the Fc fragments of the antibody components, which engage Fc receptors, complement and complement receptors on various immune cells. These Fc-mediated functions facilitate the critical interplay between innate and adaptive immune systems to impact the quality and quantity of the elicited adaptive responses. In addition to the Fc contribution, the Fab fragment also plays an immunoregulation role. The antigen-binding domains of the Fab fragment can bind their specific epitopes at high affinity to sterically occlude these antigenic sites from recognition by other antibodies. Moreover, the Fab-mediated binding has been demonstrated to induce allosteric alterations at nearby or distant antigenic sites. In this review article, we survey published studies to illuminate how the immunomodulatory functions of ICs have been investigated or utilized in a vaccination strategy to fight against an array of infectious pathogens, culminating with IC vaccine designs aimed at preventing HIV-1 infection. In particular, we highlight IC vaccine candidates that exploit Fab-mediated steric and allosteric effects to direct antibody responses away or toward the V1V2 domain, the V3 loop, and other antigenic sites on the HIV-1 envelope gp120 glycoprotein. Like other HIV-1 vaccine approaches, the path for IC-based vaccines to reach the clinic faces major hurdles yet to be overcome; however, investigations into this vaccine strategy have provided insights into the multifaceted activities of antibodies beyond their conventional roles in the host defense against HIV-1 and other microbial pathogens.
Specific PIP2 Binding Promotes Calcium Activation of TMEM16A Chloride Channels

TMEM16A is a widely expressed Ca2+-activated Cl− channel that regulates crucial physiological functions including fluid secretion, neuronal excitability, and smooth muscle contraction. There is a critical need to understand the molecular mechanisms of TMEM16A gating and regulation. However, high-resolution TMEM16A structures have failed to reveal an activated state with an unobstructed permeation pathway even with saturating Ca2+. This has been attributed to the requirement of PIP2 for preventing TMEM16A desensitization. Here, atomistic simulations show that specific binding of PIP2 to TMEM16A can lead to spontaneous opening of the permeation pathway in the Ca2+-bound state. The predicted activated state is highly consistent with a wide range of mutagenesis and functional data. It yields a maximal Cl− conductance of ~1 pS, similar to experimental estimates, and recapitulates the selectivity of larger SCN− over Cl−. The resulting molecular mechanism of activation provides a basis for understanding the interplay of multiple signals in controlling TMEM16A channel function. Chen and Jia investigate the synergistic regulating role of Ca2+ binding and the signaling lipid PIP2 in TMEM16A channel gating. Their study is significant as it provides new insights into the activated state of TMEM16A and highlights an example of functional importance of lipids in regulating membrane-associated proteins.
Distributions of restricted rotation distances

Rotation distances measure the differences in structure between rooted ordered binary trees. The one-dimensional skeleta of associahedra are rotation graphs, where two vertices representing trees are connected by an edge if they differ by a single rotation. There are no known efficient algorithms to compute rotation distance between trees and thus distances in rotation graphs. Limiting the allowed locations of where rotations are permitted gives rise to a number of notions related to rotation distance. Allowing rotations at a minimal such set of locations gives restricted rotation distance. There are linear-time algorithms to compute restricted rotation distance, where there are only two permitted locations for rotations to occur. The associated restricted rotation graph has an efficient distance algorithm. There are linear upper and lower bounds on restricted rotation distance with respect to the sizes of the reduced tree pairs. Here, we experimentally investigate the expected restricted rotation distance between two trees selected at random of increasing size and find that it lies typically in a narrow band well within the earlier proven linear upper and lower bounds.
Investigating the effect of national government physical distancing measures on depression and anxiety during the COVID-19 pandemic through meta-analysis and meta-regression.

BACKGROUND: COVID-19 physical distancing measures can potentially increase the likelihood of mental disorders. It is unknown whether these measures are associated with depression and anxiety. OBJECTIVES: To investigate meta-analytic global levels of depression and anxiety during the COVID-19 pandemic and how the implementation of mitigation strategies (i.e. public transportation closures, stay-at-home orders, etc.) impacted such disorders. DATA SOURCES: PubMed, MEDLINE, Web of Science, BIOSIS Citation Index, Current Content Connect, PsycINFO, CINAHL, medRxiv, and PsyArXiv databases for depression and anxiety prevalences; Oxford Covid-19 Government Response Tracker for the containment and closure policies indexes; Global Burden of Disease Study for previous levels of depression and anxiety. STUDY ELIGIBILITY CRITERIA: Original studies conducted during COVID-19 pandemic, which assessed categorical depression and anxiety, using PHQ-9 and GAD-7 scales (cutoff â©¾10). PARTICIPANTS AND INTERVENTIONS: General population, healthcare providers, students, and patients. National physical distancing measures. STUDY APPRAISAL AND SYNTHESIS METHODS: Meta-analysis and meta-regression. RESULTS: In total, 226 638 individuals were assessed within the 60 included studies. Global prevalence of both depression and anxiety during the COVID-19 pandemic was 24.0% and 21.3%, respectively. There were differences in the prevalence of both anxiety and depression reported across regions and countries. Asia (17.6% and 17.9%), and China (16.2% and 15.5%) especially, had the lowest prevalence of both disorders. Regarding the impact of mitigation strategies on mental health, only public transportation closures increased the prevalence of anxiety, especially in Europe. LIMITATIONS: Country-level data on physical distancing measures and previous anxiety/depression may not necessarily reflect local (i.e. city-specific) contexts. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: Mental health concerns should not be viewed only as a delayed consequence of the COVID-19 pandemic, but also as a concurrent epidemic. Our data provide support for policy-makers to consider real-time enhanced mental health services, and increase initiatives to foster positive mental health outcomes.
Single-molecule magnets: Jahn–Teller isomerism and the origin of two magnetization relaxation processes in Mn12 complexes

Abstract Different crystallographic forms of the single molecule magnet [Mn 12 O 12 (O 2 CR) 16 (H 2 O) 4 ] with a given R substituent have been isolated. X-ray structures are reported for two isomeric forms of the p -methylbenzoate complex, [Mn 12 O 12 (O 2 CC 6 H 4 - p -Me) 16 (H 2 O) 4 ]·(HO 2 CC 6 H 4 - p -Me) ( 2 ) and [Mn 12 O 12 (O 2 CC 6 H 4 - p -Me) 16 (H 2 O) 4 ]·3H 2 O ( 3 ). The Mn 12 molecules in complexes 2 and 3 are geometrical isomers differing in the positions of the H 2 O and carboxylate ligands. In complex 2 , one Mn III ion has an abnormal Jahn–Teller distortion axis oriented at an oxide ion, and thus 2 and 3 are also Jahn–Teller isomers. This reduces the symmetry of the core of complex 2 compared with that of complex 3 . Complex 2 likely has a larger tunneling matrix element and this explains why this complex shows an out-of-phase ac peak ( χ M ″) in the signal in the 2–3 K region, whereas complex 3 has its χ M ″ peak in the 4–7 K range, i.e. the rate of tunneling of magnetization is greater in complex 2 than complex 3 .
Quantum Approximate Counting with Nonadaptive Grover Iterations

Approximate Counting refers to the problem where we are given query access to a function f : [N] → {0,1}, and we wish to estimate K = #{x : f(x) = 1} to within a factor of 1+e (with high probability), while minimizing the number of queries. In the quantum setting, Approximate Counting can be done with O(min (√{N/e}, √{N/K} / e) queries. It has recently been shown that this can be achieved by a simple algorithm that only uses "Grover iterations"; however the algorithm performs these iterations adaptively. Motivated by concerns of computational simplicity, we consider algorithms that use Grover iterations with limited adaptivity. We show that algorithms using only nonadaptive Grover iterations can achieve O(√{N/e}) query complexity, which is tight.
Magnetic tweezers with magnetic flux density feedback control.

In this work, we present a single-pole magnetic tweezers (MT) device designed for integration with substrate deformation tracking microscopy and/or traction force microscopy experiments intended to explore extracellular matrix rheology and human epidermal keratinocyte mechanobiology. Assembled from commercially available off-the-shelf electronics hardware and software, the MT device is amenable to replication in the basic biology laboratory. In contrast to conventional solenoid current-controlled MT devices, operation of this instrument is based on real-time feedback control of the magnetic flux density emanating from the blunt end of the needle core using a cascade control scheme and a digital proportional–integral–derivative (PID) controller. Algorithms that compensate for a spatially non-uniform remnant magnetization of the needle core that develops during actuation are implemented into the feedback control scheme. Through optimization of PID gain scheduling, the MT device exhibits magnetization and demagnetization response times of less than 100 ms without overshoot over a wide range of magnetic flux density setpoints. Compared to current-based control, magnetic flux density-based control allows for more accurate and precise magnetic actuation forces by compensating for temperature increases within the needle core due to heat generated by the applied solenoid currents. Near field calibrations validate the ability of the MT device to actuate 4.5 μm-diameter superparamagnetic beads with forces up to 25 nN with maximum relative uncertainties of ±30% for beads positioned between 2.5 and 40 µm from the needle tip.
On Closed Shells in Nuclei

Experimental facts are summarized to show that nuclei with 20, 50, 82, or 126 neutrons or protons are particularly stable.
Advanced confocal microscopy in biophotonics and nanobiophotonics

Based on simple fiber-optic confocal approaches, we have developed some advanced biophotonics and nanobiophotonics imaging and sensing techniques which can be used as ultrahigh-resolution systems for imaging/sensing beyond the diffraction barrier in the subwavelength nanometric range at cellular, intracellular and bulk tissue level.
Application of Dispersion Relations to the Photodisintegration of the Deuteron

The calculation of the matrix element of the process gamma + d - n + p by dispersion techniques is considered. There are twelve invariant amplitudes; the covariant form of the transition amplitude is related to the noncovariant (Pauli matrix) form, and this is further related to partial wave amplitudes, keeping however only the dipole amplitudes. The Born terms of the dipole amplitudes are derived, and the dispersion relations for the dipole amplitudes are written down and solved in a low energy approximation in which the n-p final state rescattering is taken into account, but no other higher order effects. In an appendix these calculations are performed directly in the nonrelativistic limit to illustrate the essential simplicity of the technique. No light is shed on the well known discrepancy between theory and experiment for the threshold M1 amplitude; the nearest (anomalous) singularities, at least, will have to be included in order for the dispersion calculation to be sufficiently accurate. But we remark that the form of the amplitude implies a correlation between the threshold value of the amplitude and its energy dependence, a correlation that would be interesting to check experimentally. (auth)
Local and global homogeneity for three obstinate spheres

Abstract In this note we complete a study of globally homogeneous Riemannian quotients Γ \ ( M , d s 2 ) in positive curvature. Specifically, M is a homogeneous space G / H that admits a G–invariant Riemannian metric of strictly positive sectional curvature, and d s 2 is a G–invariant Riemannian metric on M, not necessarily normal and not necessarily positively curved. The Homogeneity Conjecture is that Γ \ ( M , d s 2 ) is (globally) homogeneous if and only if ( M , d s 2 ) is homogeneous and every γ ∈ Γ is of constant displacement on ( M , d s 2 ) . In an earlier paper we verified that conjecture for all homogeneous spaces that admit an invariant Riemannian metric of positive curvature — with three exceptions, all of them odd dimensional spheres, which surprisingly did not yield to the earlier approaches. In this note we deal with those exceptions: we develop some methods that let us verify the Homogeneity Conjecture for those three obstinate spheres. That completes verification of the Homogeneity Conjecture in positive curvature.
Metastasis is altered through multiple processes regulated by the E2F1 transcription factor.

The E2F family of transcription factors is important for many cellular processes, from their canonical role in cell cycle regulation to other roles in angiogenesis and metastasis. Alteration of the Rb/E2F pathway occurs in various forms of cancer, including breast cancer. E2F1 ablation has been shown to decrease metastasis in MMTV-Neu and MMTV-PyMT transgenic mouse models of breast cancer. Here we take a bioinformatic approach to determine the E2F1 regulated genomic alterations involved in the metastatic cascade, in both Neu and PyMT models. Through gene expression analysis, we reveal few transcriptome changes in non-metastatic E2F1−/− tumors relative to transgenic tumor controls. However investigation of these models through whole genome sequencing found numerous differences between the models, including differences in the proposed tumor etiology between E2F1−/− and E2F1+/+ tumors induced by Neu or PyMT. For example, loss of E2F1 within the Neu model led to an increased contribution of the inefficient double stranded break repair signature to the proposed etiology of the tumors. While the SNV mutation burden was higher in PyMT mouse tumors than Neu mouse tumors, there was no statistically significant differences between E2F WT and E2F1 KO mice. Investigating mutated genes through gene set analysis also found a significant number of genes mutated in the cell adhesion pathway in E2F1−/− tumors, indicating this may be a route for disruption of metastasis in E2F1−/− tumors. Overall, these findings illustrate the complicated nature of uncovering drivers of the metastatic process.
GHG Mitigation Potential and Cost in Tropical Forestry - Relative Role for Agroforestry

This paper summarizes studies of carbon mitigation potential (MP) and costs of forestry options in seven developing countries with a focus on the role of agroforestry. A common methodological approach known as comprehensive mitigation assessment process (COMAP) was used in each study to estimate the potential and costs between 2000 and 2030. The approach requires the projection of baseline and mitigation land-use scenarios derived from the demand for forest products and forestland for other uses such as agriculture and pasture. By using data on estimated carbon sequestration, emission avoidance, costs and benefits, the model enables one to estimate cost effectiveness indicators based on monetary benefit per t C, as well as estimates of total mitigation costs and potential when the activities are implemented at equilibrium level. The results show that about half the MP of 6.9 Gt C (an average of 223 Mt C per year) between 2000 and 2030 in the seven countries could be achieved at a negative cost, and the other half at costs not exceeding $100 per t C. Negative cost indicates that non-carbon revenue is sufficient to offset direct costs of about half of the options. The agroforestry options analyzed bear a significant proportion ofmore » the potential at medium to low cost per t C when compared to other options. The role of agroforestry in these countries varied between 6% and 21% of the MP, though the options are much more cost effective than most due to the low wage or opportunity cost of rural labor. Agroforestry options are attractive due to the large number of people and potential area currently engaged in agriculture, but they pose unique challenges for carbon and cost accounting due to the dispersed nature of agricultural activities in the tropics, as well as specific difficulties arising from requirements for monitoring, verification, leakage assessment and the establishment of credible baselines.« less
Observations of Hawking radiation: the Page curve and baby universes

We reformulate recent insights into black hole information in a manner emphasizing operationally-defined notions of entropy, Lorentz-signature descriptions, and asymptotically flat spacetimes. With the help of replica wormholes, we find that experiments of asymptotic observers are consistent with black holes as unitary quantum systems, with density of states given by the Bekenstein-Hawking formula. However, this comes at the cost of superselection sectors associated with the state of baby universes. Spacetimes studied by Polchinski and Strominger in 1994 provide a simple illustration of the associated concepts and techniques, and we argue them to be a natural late-time extrapolation of replica wormholes. The work aims to be self-contained and, in particular, to be accessible to readers who have not yet mastered earlier formulations of the ideas above.
A Stochastic Homotopy Tracking Algorithm for Parametric Systems of Nonlinear Equations

The homotopy continuation method has been widely used in solving parametric systems of nonlinear equations. But it can be very expensive and inefficient due to singularities during the tracking even though both start and end points are non-singular. The current tracking algorithms focus on the adaptivity of the stepsize by estimating the distance to the singularities but cannot avoid these singularities during the tracking. We present a stochastic homotopy tracking algorithm that perturbs the original parametric system randomly each step to avoid the singularities. We then prove that the stochastic solution path introduced by this new method is still closed to the original solution path theoretically. Moreover, several homotopy examples have been tested to show the efficiency of the stochastic homotopy tracking method.
Blessing or curse? Institutional investment in leveraged ETFs

Abstract We document the increasing role leveraged exchange traded funds (ETFs) play in institutional portfolios over time. A subset of independent investment advisors, quasi-indexers, and transient portfolio managers all make substantive use of these tools. Leveraged ETFs can be used for diversification or to implement strategic bets. Empirical tests suggest that institutional holders of leveraged ETFs predict weak portfolio performance in aggregate, consistent with manager hubris, especially among the set of institutional managers most likely to lack management skill. Interestingly, managers appear to reduce positions in leveraged ETFs following good past performance, potentially to lock in good returns, consistent with compensation-based incentives.
A self-stabilizing algorithm for the maximum flow problem

The maximum flow problem is a fundamental problem in graph theory and combinatorial optimization with a variety of important applications. Known distributed algorithms for this problem do not tolerate faults or adjust to dynamic changes in network topology. This paper presents a distributed self-stabilizing algorithm for the maximum flow problem. Starting from an arbitrary state, the algorithm computes the maximum flow in an acyclic network in finitely many steps. Since the algorithm is self-stabilizing, it is inherently tolerant to transient faults. It can automatically adjust to topology changes and to changes in other parameters of the problem. The paper presents results obtained by extensively experimenting with the algorithm. Two main observations based on these results are (1) the algorithm requires fewer than n2 moves for almost all test cases and (2) the algorithm consistently performs at least as well as a distributed implementation of the well-known Goldberg-Tarjan algorithm for almost all test cases. The paper ends with the conjecture that the algorithm correctly computes a maximum flow even in networks that contain cycles.
Spontaneous neural synchrony links intrinsic spinal sensory and motor networks during unconsciousness.

Non-random functional connectivity during unconsciousness is a defining feature of supraspinal networks. However, its generalizability to intrinsic spinal networks remains incompletely understood. Previously, Barry et al. (2014) used fMRI to reveal bilateral resting state functional connectivity within sensory-dominant and, separately, motor-dominant regions of the spinal cord. Here, we record spike trains from large populations of spinal interneurons in vivo in rats and demonstrate that spontaneous functional connectivity also links sensory- and motor-dominant regions during unconsciousness. The spatiotemporal patterns of connectivity could not be explained by latent afferent activity or by populations of interconnected neurons spiking randomly. We also document connection latencies compatible with mono- and di-synaptic interactions and putative excitatory and inhibitory connections. The observed activity is consistent with the hypothesis that salient, experience-dependent patterns of neural transmission introduced during behavior or by injury/disease are reactivated during unconsciousness. Such a spinal replay mechanism could shape circuit-level connectivity and ultimately behavior.
Improved Corruption Robust Algorithms for Episodic Reinforcement Learning

We study episodic reinforcement learning under unknown adversarial corruptions in both the rewards and the transition probabilities of the underlying system. We propose new algorithms which, compared to the existing results in (Lykouris et al., 2020), achieve strictly better regret bounds in terms of total corruptions for the tabular setting. To be specific, firstly, our regret bounds depend on more precise numerical values of total rewards corruptions and transition corruptions, instead of only on the total number of corrupted episodes. Secondly, our regret bounds are the first of their kind in the reinforcement learning setting to have the number of corruptions show up additively with respect to $\min\{\sqrt{T}, \text{PolicyGapComplexity}\}$ rather than multiplicatively. Our results follow from a general algorithmic framework that combines corruption-robust policy elimination meta-algorithms, and plug-in reward-free exploration sub-algorithms. Replacing the meta-algorithm or sub-algorithm may extend the framework to address other corrupted settings with potentially more structure.
The Restoration of Obliterated Stamped Serial Numbers by Ultrasonically Induced Cavitation in Water

Serial numbers on stolen property or guns are often removed by filing or grinding. On recovered property it is necessary to restore the numbers sufficiently so that they may be read or photographed before they can serve as evidence. In recent years aluminum and metals other than iron and steel have been increasingly used for vehicles, tools, firearms, etc [1]. Several restoration methods exist for each of these types of metals, but they involve chemical [2], magnetic, dye penetrant, or heat treatment methods. Also, each method is usually unique for the type of metal being examined, and many of these methods allow the numbers to show up only temporarily, with great skill being required to gain the needed photographic evidence. Furthermore, the specimen usually requires a series of mechanical and chemical treatments such as grinding, polishing, and etching, before the numbers can be seen. These treatments all run the risk of losing any residual traces of the numbers due to the restoration technique itself.
An experimental investigation of resilience decision making in repeated disasters

Given the growing prevalence of catastrophic events and health epidemics, policymakers are increasingly searching for effective strategies to encourage firms to invest in resilience rather than relying on insurance or government assistance. Too often, however, resilience research focuses on decisions made by firms and emergency planners in the context of "one-off" events. We extend this research by examining resilience decision making in the more realistic context of repeated catastrophic events. Using a population of professional managers of middle market firms and a university experimental economics subject pool, we conduct a series of controlled experiments on the decision to invest in inventories to improve firm resilience to repeated catastrophic events. While existing economic and supply chain resilience research has focused on resilience in terms of avoiding some magnitude of economic losses, existing research omits a focus on the probability of those losses. Controlled experiments can evaluate the influence of probability more effectively than observational data by better controlling for magnitude and more easily accounting for repeated events. We find that decision makers are less likely to make resilience investments when a disaster has recently occurred. We further find that advisory information alone is insufficient to motivate resilience investments by firms. It must be substantiated by a history of advisory accuracy. However, we find that this effect is heavily moderated by the type of advisory information provided; we find that firm managers are much more likely to trust precautionary advice.
Off-Policy Confidence Sequences

We develop confidence bounds that hold uniformly over time for off-policy evaluation in the contextual bandit setting. These confidence sequences are based on recent ideas from martingale analysis and are non-asymptotic, non-parametric, and valid at arbitrary stopping times. We provide algorithms for computing these confidence sequences that strike a good balance between computational and statistical efficiency. We empirically demonstrate the tightness of our approach in terms of failure probability and width and apply it to the "gated deployment" problem of safely upgrading a production contextual bandit system.
Observations of DC shift and chugging in a pressurized rotating detonation combustor

Abstract Rotating detonation combustors are prone to a wide range of off-design behaviors during both atmospheric and pressurized operation. The current manuscript deals with the transient mean pressure change seen in back-pressurized combustors after ignition. Using experimental high-speed pressure data acquired during this transience, we report two distinct, but overlapping, mechanisms that are well-known in deflagrative rocket combustors, but are not currently considered in rotating detonation combustors: DC shift and chugging. The former is characterized by sudden and seemingly random alterations of the time-averaged chamber pressure during operation, not unlike the same behavior observed in conventional rockets during instability onset. The latter is a low frequency instability that is inherently coupled to the reactants feed, causing significant oscillations of the mean chamber pressure. We show that these phenomena are strongly linked, where onset of chugging oscillations alter the frequency and pressure of the operating mode, which in turn produces a DC shift of the mean chamber pressure. To discern this complex interaction, we use multivariate polynomial curve-fitting, considering all the appropriate parameters to arrive at an empirical formulation that is seen to reasonably match the observed pressure transience after ignition.
Properties of the quantum vacuum calculated from its structure

Physicists have speculated about the properties of the quantum vacuum for at least 85 years; however, only recently have they understood the quantum vacuum sufficiently well to begin making testable predictions. Specifically, using Maxwell's equations to describe the interaction of the electromagnetic field with charged lepton - antilepton vacuum fluctuations, it has been possible to calculate the permittivity of the vacuum, the speed of light in the vacuum, and the fine structure constant. Physicists are now also beginning to successfully address problems in cosmology based on properties of the quantum vacuum. The terms ``vacuum catastrophe'' and ``old cosmological problem'' refer, respectively, to the predictions that the vacuum energy density and the cosmological constant are both approximately 120 orders of magnitude larger than the observed values. Using properties of the quantum vacuum and well-established physics, it is possible to demonstrate that the huge vacuum energy cannot transfer energy to normal matter; accordingly, vacuum energy contributes neither to the observed energy density of the universe nor to the cosmological constant, which plays a central role in the accelerating expansion of the universe.
Elephant seal muscle cells adapt to sustained glucocorticoid exposure by shifting their metabolic phenotype.

Elephant seals experience natural periods of prolonged food deprivation while breeding, molting, and undergoing postnatal development. Prolonged food deprivation in elephant seals increases circula...
Somatic aging pathways regulate reproductive plasticity in Caenorhabditis elegans

In animals, early-life stress can result in programmed changes in gene expression that can affect their adult phenotype. In C. elegans nematodes, starvation during the first larval stage promotes entry into a stress-resistant dauer stage until environmental conditions improve. Adults that have experienced dauer (postdauers) retain a memory of early-life starvation that results in gene expression changes and reduced fecundity. Here, we show that the endocrine pathways attributed to the regulation of somatic aging in C. elegans adults lacking a functional germline also regulate the reproductive phenotypes of postdauer adults that experienced early-life starvation. We demonstrate that postdauer adults reallocate fat to benefit progeny at the expense of the parental somatic fat reservoir and exhibit increased longevity compared to controls. Our results also show that the modification of somatic fat stores due to parental starvation memory is inherited in the F1 generation and may be the result of crosstalk between somatic and reproductive tissues mediated by the germline nuclear RNAi pathway.
Modeling and Optimization of Latency in Erasure-coded Storage Systems

The advent of Big Data analytics and cloud computing has resulted in an unprecedented increase in the demand for distributed data storage demand. Companies are constantly on the lookout for ways of reducing this cost and improving reliability. Erasure coding has emerged as a promising technique to achieve these goals and most major tech companies have adopted it. However, one major issue in such systems is the characterization and optimization of access latency when data objects are erasure coded in distributed storage. In this monograph, the authors provide a review of recent theoretical and practical progress on systems that employ erasure codes for distributed storage. Starting with an overview the key challenges and research problems, the authors give an overview of different models and approaches that have been developed to quantify latency of erasure-coded storage. They also extend the discussions to video streaming from erasure-coded distributed storage systems. Practical implementations of erasure-coded storage are then discussed in real-world storage systems such as in content delivery and caching. This monograph is aimed at students, researchers and practitioners in information theory active in the research and development of modern day distributed storage systems.
Foreign aid, public investment, and the informal economy

This paper uses a two-sector open economy model to examine the dynamic absorption of foreign aid in the presence of both formal and informal production. Calibrating the model to yield a long-run equilibrium consistent with sample averages for 72 aid-recipient developing countries for the period 1990-2017, we show that an increase in foreign aid impacts the sectoral composition of the recipient economy, driving resources into the informal sector, and away from the formal sector. Further, if aid is untied (say, provided for general budget support), then the expansion of the informal sector can lead to a contraction of the aggregate economy through the Dutch Disease effect. If the recipient government’s objective is to drive an economic expansion by increasing the share of formal production, then re-allocating existing aid to public investment is more effective than an increase in the aggregate level of aid.
Fair Machine Learning Under Partial Compliance

Typically, fair machine learning research focuses on a single decision maker and assumes that the underlying population is stationary. However, many of the critical domains motivating this work are characterized by competitive marketplaces with many decision makers. Realistically, we might expect only a subset of them to adopt any non-compulsory fairness-conscious policy, a situation that political philosophers call partial compliance. This possibility raises important questions: how does partial compliance and the consequent strategic behavior of decision subjects affect the allocation outcomes? If k% of employers were to voluntarily adopt a fairness-promoting intervention, should we expect k% progress (in aggregate) towards the benefits of universal adoption, or will the dynamics of partial compliance wash out the hoped-for benefits? How might adopting a global (versus local) perspective impact the conclusions of an auditor? In this paper, we propose a simple model of an employment market, leveraging simulation as a tool to explore the impact of both interaction effects and incentive effects on outcomes and auditing metrics. Our key findings are that at equilibrium: (1) partial compliance by k% of employers can result in far less than proportional (k%) progress towards the full compliance outcomes; (2) the gap is more severe when fair employers match global (vs local) statistics; (3) choices of local vs global statistics can paint dramatically different pictures of the performance vis-a-vis fairness desiderata of compliant versus non-compliant employers; (4) partial compliance based on local parity measures can induce extreme segregation. Finally, we discuss implications for auditors and insights concerning the design of regulatory frameworks.
The Inductive Graph Dimension from the Minimum Edge Clique Cover

In this paper we prove that the inductively defined graph dimension has a simple additive property under the join operation. The dimension of the join of two simple graphs is one plus the sum of the dimensions of the component graphs: $$\mathrm {dim\,} (G_1+ G_2) = 1 +\mathrm {dim\,} G_1+ \mathrm {dim\,} G_2$$ . We use this formula to derive an expression for the inductive dimension of an arbitrary finite simple graph from its minimum edge clique cover. A corollary of the formula is that any arbitrary finite simple graph whose maximal cliques are all of order N has dimension $$N{-}1$$ . We finish by finding lower and upper bounds on the inductive dimension of a simple graph in terms of its clique number.