cssi/SciSciGPT-SciSciNet huggingface dataset:
The Minor Matrix Protein VP24 from Ebola Virus Lacks Direct Lipid-Binding Properties

Viral protein 24 (VP24) from Ebola virus (EBOV) was first recognized as a minor matrix protein that associates with cellular membranes. However, more recent studies shed light on its roles in inhibiting viral genome transcription and replication, facilitating nucleocapsid assembly and transport, and interfering with immune responses in host cells through downregulation of interferon (IFN)-activated genes. Thus, whether VP24 is a peripheral protein with lipid-binding ability for matrix layer recruitment has not been explored. Here, we examined the lipid-binding ability of VP24 with a number of lipid-binding assays. The results indicated that VP24 lacked the ability to associate with lipids tested regardless of VP24 posttranslational modifications. We further demonstrate that the presence of the EBOV major matrix protein VP40 did not promote VP24 membrane association in vitro or in cells. Further, no protein–protein interactions between VP24 and VP40 were detected by co-immunoprecipitation. Confocal imaging and cellular membrane fractionation analyses in human cells suggested VP24 did not specifically localize at the plasma membrane inner leaflet. Overall, we provide evidence that EBOV VP24 is not a lipid-binding protein and its presence in the viral matrix layer is likely not dependent on direct lipid interactions.
Psychological Resilience and Health Among Older Adults: A Comparison of Personal Resources.

OBJECTIVES Research on life course inequality and successful aging has sought to understand how events and challenges may lead to poor outcomes in later life for some individuals, while others fare well in the face of adversity. Among internalized resources, research suggests psychological resilience is protective in the face of challenges, but little is known about the predictive efficacy of this measure compared to other resources such as mastery. This paper examines connections between psychological resilience and later life health compared to other internalized resources. METHOD Standardized associations between 4 resources (resilience, mastery, optimism, hopelessness) and 5 health outcomes were tested using short-term health transitions and longer term health trajectories in a structural equation modeling (SEM) framework using the Leave Behind Questionnaire (LBQ) and linked Health and Retirement Study (HRS) between 2006/2008 and 2014/2016 (n = 11,050-12,823). RESULTS Psychological resilience had consistent and robust associations with health transitions and trajectories. Further, the effects of this resource were generally 4-10 times greater than for mastery, optimism, and hopelessness in combined models. Trajectory analyses replicate these findings and suggest the beneficial associations of resilience over time were persistent for some health outcomes, and cumulative for others. DISCUSSION The results suggest that psychological resilience is powerfully associated with health in later life, with substantially greater predictive efficacy than other commonly used resource measures. Future research should establish how this intrapersonal resource works alongside structural and interpersonal resources to promote and protect health and functioning in the face of challenges and adversity.
The Right to Be and Become: Black Home-Educators as Child Privacy Protectors

The right to privacy is one of the most fundamental rights in American jurisprudence. In 1890, Samuel D. Warren and Louis D. Brandeis conceptualized the right to privacy as the right to be let alone and inspired privacy jurisprudence that tracked their initial description. Warren and Brandeis conceptualized further that this right was not exclusively meant to protect one’s body or physical property. Privacy rights were protective of “the products and the processes of the mind” and the “inviolate personality.” Privacy was further understood to protect the ability to “live one’s life as one chooses, free from assault, intrusion or invasion except as can be justified by the clear needs of community living under a government of law.” Case law supported and extended their theorization by recognizing that privacy is essentially bound up in an individual’s ability to live a self-authored and self-curated life without unnecessary intrusions and distractions. Hence, privacy may be viewed as the right of individuals to be and become themselves. This right is well-established; however, scholars have vastly under- theorized the right to privacy as it intersects with racial discrimination and childhood. Specifically, the ways in which racial discrimination strips Black people—and therefore Black children—of privacy rights and protections, and the ways in which Black people reclaim and reshape those rights and protections remain a dynamic and fertile space, ripe for exploration yet unacknowledged by privacy law scholars. The most vulnerable members of the Black population, children, rely on their parents to protect their rights until they are capable of doing so themselves. Still, the American education system exposes Black children to racial discrimination that results in life-long injuries ranging from the psychological harms of daily racial micro-aggressions and assaults, to disproportionate exclusionary discipline and juvenile incarceration. One response to these ongoing and often traumatic incursions is a growing number of Black parents have decided to remove their children from traditional school settings. Instead, these parents provide their children with home- education in order to protect their children’s right to be and become in childhood.
Labile carbon limits late winter microbial activity near Arctic treeline

Soil microbial communities remain active during much of the Arctic winter, despite deeply frozen soils. Overwinter microbial activity affects the global carbon (C) budget, nutrient cycling, and vegetation composition. Microbial respiration is highly temperature sensitive in frozen soils, as liquid water and solute availability decrease rapidly with declining temperature. Climate warming and changes in snowpack are leading to warmer Arctic winter soils. Warmer winter soils are thought to yield greater microbial respiration of available C, greater overwinter CO2 efflux and greater nutrient availability to plants at thaw. Using field and laboratory observations and experiments, we demonstrate that persistently warm winter soils can lead to labile C starvation and reduced microbial respiration, despite the high C content of most Arctic soils. If winter soils continue to warm, microbial C limitation will reduce expected CO2 emissions and alter soil nutrient cycling, if not countered by greater labile C inputs. Soil microbial communities remain active throughout much of the Arctic winter, and Arctic winters are warming dramatically. Here, the authors show that persistently warm winter soils can lead to labile carbon starvation and reduced microbial respiration, despite the high carbon content of most Arctic soils.
Control in the presence of manipulators: cooperative and competitive cases

Control and manipulation are two of the most studied types of attacks on elections. In this paper, we study the complexity of control attacks on elections in which there are manipulators. We study both the case where the “chair” who is seeking to control the election is allied with the manipulators, and the case where the manipulators seek to thwart the chair. In the latter case, we see that the order of play substantially influences the complexity. We prove upper bounds, holding over every election system with a polynomial-time winner problem, for all standard control cases, and some of these bounds are at the second or third level of the polynomial hierarchy, and we provide matching lower bounds to prove these tight. Nonetheless, for important natural systems the complexity can be much lower. We prove that for approval and plurality elections, the complexity of even competitive clashes between a controller and manipulators falls far below those high bounds, even as low as polynomial time. Yet for a Borda-voting case we show that such clashes raise the complexity unless NP = coNP.
Sequence Characterization and Molecular Modeling of Clinically Relevant Variants of the SARS-CoV-2 Main Protease.

The SARS-CoV-2 main protease (Mpro) is essential to viral replication and cleaves highly specific substrate sequences, making it an obvious target for inhibitor design. However, as for any virus, SARS-CoV-2 is subject to constant neutral drift and selection pressure, with new Mpro mutations arising over time. Identification and structural characterization of Mpro variants is thus critical for robust inhibitor design. Here we report sequence analysis, structure predictions, and molecular modeling for seventy-nine Mpro variants, constituting all clinically observed mutations in this protein as of April 29, 2020. Residue substitution is widely distributed, with some tendency toward larger and more hydrophobic residues. Modeling and protein structure network analysis suggest differences in cohesion and active site flexibility, revealing patterns in viral evolution that have relevance for drug discovery.
On Well-Dominated Graphs

A graph is well-dominated if all of its minimal dominating sets have the same cardinality. It is proved that there are exactly eleven connected, well-dominated, triangle-free graphs whose domination number is at most 3. We prove that at least one of the factors is well-dominated if the Cartesian product of two graphs is well-dominated. In addition, we show that the Cartesian product of two connected, triangle-free graphs is well-dominated if and only if both graphs are complete graphs of order 2. Under the assumption that at least one of the connected graphs G or H has no isolatable vertices, we prove that the direct product of G and H is well-dominated if and only if either $$G=H=K_3$$ or $$G=K_2$$ and H is either the 4-cycle or the corona of a connected graph. Furthermore, we show that the disjunctive product of two connected graphs is well-dominated if and only if one of the factors is a complete graph and the other factor has domination number at most 2.
Hyperbolicity and cubulability are preserved under elementary equivalence

The following properties are preserved under elementary equivalence, among finitely generated groups: being hyperbolic (possibly with torsion), being hyperbolic and cubulable, and being a subgroup of a hyperbolic group. In other words, if a finitely generated group G has the same first-order theory as a group possessing one of the previous property, then G enjoys this property as well.
Sensitive detection of Cre-mediated recombination using droplet digital PCR reveals Tg(BGLAP-Cre) and Tg(DMP1-Cre) are active in multiple non-skeletal tissues

Abstract In humans, somatic activating mutations in PIK3CA are associated with skeletal overgrowth. In order to determine if activated PI3K signaling in bone cells causes overgrowth, we used Tg(BGLAP-Cre) and Tg(DMP1-Cre) mouse strains to somatically activate a disease-causing conditional Pik3ca allele (Pik3caH1047R) in osteoblasts and osteocytes. We observed Tg(BGLAP-Cre);Pik3caH1047R/+ offspring were born at the expected Mendelian frequency. However, these mice developed cutaneous lymphatic malformations and died before 7 weeks of age. In contrast, Tg(DMP1-Cre);Pik3caH1047R/+ offspring survived and had no cutaneous lymphatic malformations. Assuming that Cre-activity outside of the skeletal system accounted for the difference in phenotype between Tg(BGLAP-Cre);Pik3caH1047R/+ and Tg(DMP1-Cre);Pik3caH1047R/+ mice, we developed sensitive and specific droplet digital PCR (ddPCR) assays to search for and quantify rates of Tg(BGLAP-Cre)- and Tg(DMP1-Cre)-mediated recombination in non-skeletal tissues. We observed Tg(BGLAP-Cre)-mediated recombination in several tissues including skin, muscle, artery, and brain; two CNS locations, hippocampus and cerebellum, exhibited Cre-mediated recombination in >5% of cells. Tg(DMP1-Cre)-mediated recombination was also observed in muscle, artery, and brain. Although we cannot preclude that differences in phenotype between mice with Tg(BGLAP-Cre)- and Tg(DMP1-Cre)-mediated PIK3CA activation are due to Cre-recombination being induced at different stages of osteoblast differentiation, differences in recombination at non-skeletal sites are the more likely explanation. Since unanticipated sites of recombination can affect the interpretation of data from experiments involving conditional alleles, we recommend ddPCR as a good first step for assessing efficiency, leakiness, and off-targeting in experiments that employ Cre-mediated or Flp-mediated recombination.
Asymptotically optimal load balancing in large-scale heterogeneous systems with multiple dispatchers

Abstract We consider the load balancing problem in large-scale heterogeneous systems with multiple dispatchers. We introduce a general framework called Local-Estimation-Driven (LED). Under this framework, each dispatcher keeps local (possibly outdated) estimates of the queue lengths for all the servers, and the dispatching decision is made purely based on these local estimates. The local estimates are updated via infrequent communications between dispatchers and servers. We derive sufficient conditions for LED policies to achieve throughput optimality and delay optimality in heavy-traffic, respectively. These conditions directly imply delay optimality for many previous local-memory based policies in heavy traffic. Moreover, the results enable us to design new delay optimal policies for heterogeneous systems with multiple dispatchers. Finally, the heavy-traffic delay optimality of the LED framework also sheds light on a recent open question on how to design optimal load balancing schemes using delayed information.
Renin-Angiotensin-Aldosterone System Inhibitor Use and Mortality in Pulmonary Hypertension: Insights From the Veterans Affairs Clinical Assessment Reporting and Tracking Database

Background The renin-angiotensin-aldosterone system (RAAS) contributes to pulmonary hypertension (PH) pathogenesis. Although animal data suggest that RAAS inhibition attenuates PH, it is unknown if RAAS inhibition is beneficial in PH patients. Research Question Is RAAS inhibitor use associated with lower mortality in a large cohort of patients with hemodynamically confirmed PH? Study Design and Methods We used the Department of Veterans Affairs Clinical Assessment Reporting and Tracking Database to study retrospectively relationships between RAAS inhibitors (angiotensin converting enzyme inhibitors [ACEIs], angiotensin receptor blockers [ARBs], and aldosterone antagonists [AAs]) and mortality in 24,221 patients with hemodynamically confirmed PH. We evaluated relationships in the full and in propensity-matched cohorts. Analyses were adjusted for demographics, socioeconomic status, comorbidities, disease severity, and comedication use in staged models. Results ACEI and ARB use was associated with improved survival in unadjusted Kaplan-Meier survival analyses in the full cohort and the propensity-matched cohort. This relationship was insensitive to adjustment, independent of pulmonary artery wedge pressure, and also was observed in a cohort restricted to individuals with precapillary PH. AA use was associated with worse survival in unadjusted Kaplan-Meier survival analyses in the full cohort; however, AA use was associated less robustly with mortality in the propensity-matched cohort and was not associated with worse survival after adjustment for disease severity, indicating that AAs in real-world practice are used preferentially in sicker patients and that the unadjusted association with increased mortality may be an artifice of confounding by indication of severity. Interpretation ACEI and ARB use is associated with lower mortality in veterans with PH. AA use is a marker of disease severity in PH. ACEIs and ARBs may represent a novel treatment strategy for diverse PH phenotypes.
Fast Execute-Only Memory for Embedded Systems

Remote code disclosure attacks threaten embedded systems as they allow attackers to steal intellectual property or to find reusable code for use in control-flow hijacking attacks. Execute-only memory (XOM) prevents remote code disclosures, but existing XOM solutions either require a memory management unit that is not available on ARM embedded systems or incur significant overhead.We present PicoXOM: a fast and novel XOM system for ARMv7-M and ARMv8-M devices which leverages ARM’s Data Watchpoint and Tracing unit along with the processor’s simplified memory protection hardware. On average, PicoXOM incurs 0.33% performance overhead and 5.89% code size overhead on two benchmark suites and five real-world applications.
Elicitation Complexity of Statistical Properties

A property, or statistical functional, is said to be elicitable if it minimizes expected loss for some loss function. The study of which properties are elicitable sheds light on the capabilities and limitations of point estimation and empirical risk minimization. While recent work asks which properties are elicitable, we instead advocate for a more nuanced question: how many dimensions are required to indirectly elicit a given property? This number is called the elicitation complexity of the property. We lay the foundation for a general theory of elicitation complexity, including several basic results about how elicitation complexity behaves, and the complexity of standard properties of interest. Building on this foundation, our main result gives tight complexity bounds for the broad class of Bayes risks. We apply these results to several properties of interest, including variance, entropy, norms, and several classes of financial risk measures. We conclude with discussion and open directions.
Building Galactic Disks in Triaxial Dark Matter Halos

We review our recent work on the formation and evolution of disks with in triaxial dark matter (DM) halos by means of numerical simulations, including star formation and feedback from stellar evolution. The growing disks are strongly in fluenced by shapes of DM halos and modify them in turn. Disk parameters are in a broad agreement with those in the local universe. Gas-rich stellar bars grow in tandem with the disk and facilitate the angular momentum redistribution in the system and radial gas inflow. Nested bars appear to form as a by-product. Interactions between various non-axisymmetric components -- bars, disks and halos lead to decay of bars or washing out of ellipticity in the inner halo.
Metamodel Based Forward and Inverse Design for Passive Vibration Suppression

Aperiodic metamaterials represent a class of structural systems that are composed of different building blocks (cells), instead of a self-repeating chain of the same unit cells. Optimizing aperiodic cellular structural systems thus presents high-dimensional problems that are challenging to solve using purely high-fidelity structural optimization approaches. Specialized analytical modeling along with metamodel based optimization can provide a more tractable alternative solution approach. To this end, this paper presents a design automation framework applied to a 1D metamaterial system, namely a drill string, where vibration suppression is of utmost importance. The drill string comprises a set of nonuniform rings attached to the outer surface of a longitudinal rod. As such, the resultant system can now be perceived as an aperiodic 1D metamaterial with each ring/gap representing a cell. Despite being a 1D system, the simultaneous consideration of multiple DoF (i.e., torsional, axial, and lateral motions) poses significant computational challenges. Therefore, a transfer matrix method (TMM) is employed to analytically determine the frequency response of the drill string. A suite of neural networks (ANN) is trained on TMM samples (which present minute-scale computing costs per evaluation), to model the frequency response. ANN-based optimization is then performed to minimize mass subject to constraints on the gap between consecutive resonance peaks in one case, and minimizing this gap in the second case, leading to crucial improvements over baselines. Further novel contribution occurs through the development of an inverse modeling approach that can instantaneously produce the 1D metamaterial design with minimum mass for a given desired non-resonant frequency range. This is accomplished by using invertible neural networks, and results show promising alignment with forward solutions.
Radio Sources in the Nearby Universe

We identified 15,658 NVSS radio sources among the 55,288 2MASX galaxies brighter than $k_\mathrm{20fe} = 12.25$ at $\lambda = 2.16\,\mu\mathrm{m}$ and covering the $\Omega =7.016$ sr of sky defined by J2000 $\delta > -40^\circ$ and $\vert b \vert > 20^\circ$. The complete sample of 15,043 galaxies with 1.4 GHz flux densities $S \geq 2.45 \mathrm{~mJy}$ contains a 99.9% spectroscopically complete subsample of 9,517 galaxies with $k_\mathrm{20fe} \leq 11.75$. We used only radio and infrared data to quantitatively distinguish radio sources powered primarily by recent star formation from those powered by active galactic nuclei. The radio sources with $\log[L(\mathrm{W~Hz}^{-1})] > 19.3$ that we used to derive the local spectral luminosity and power-density functions account for $>99$% of the total 1.4~GHz spectral power densities $U_\mathrm{SF} = (1.54 \pm 0.20) \times 10^{19} \mathrm{~W~Hz}^{-1} \mathrm{~Mpc}^{-3}$ and $U_\mathrm{AGN} = (4.23 \pm 0.78) \times 10^{19} \mathrm{~W~Hz}^{-1} \mathrm{~Mpc}^{-3}$ in the universe today, and the spectroscopic subsample is large enough that the quoted errors are dominated cosmic variance. The recent comoving star-formation rate density indicated by $U_\mathrm{SF}$ is $\psi \approx 0.015~ M_\odot \mathrm{~yr}^{-1} \mathrm{~Mpc}^{-3}$.
Properties of H II Regions in the Centers of Nearby Galaxies

As part of an optical spectroscopic survey of nearby bright galaxies, we have identified a sample of over 200 emission-line nuclei having optical spectra resembling those of giant extragalactic H II regions. Such "H II nuclei," powered by young, massive stars, are found in a substantial fraction of nearby galaxies, especially those of late Hubble type. This paper summarizes the observational characteristics of H II nuclei, considers the variation of their properties with Hubble type, and compares the nuclear H II regions with those found in galaxy disks. Similarities and differences between H II nuclei and luminous starburst nuclei are additionally noted. Nuclei in early-type disk galaxies (S0-SBc) on average have low excitation, and hence high oxygen abundance (from ~1.1 to 3.3 times the solar value), whereas those in late-type systems (Sc-I0) have excitations spanning a wide range (corresponding to less than 0.25-3.5 times the solar oxygen abundance). The Hα luminosities of early-type nuclei greatly exceed those of later types. The enhancement of massive star formation may be linked to the higher efficiency with which bars can drive gaseous inflow in systems with prominent bulges. The early-type systems also have higher amounts of internal extinction and higher electron densities. The physical properties of H II nuclei resemble those of giant H II regions in spiral disks in some ways, but they differ in several others. The two groups emit comparable Hα luminosities and generally have similar electron densities. Because of their unique location in the galaxies, nuclear H II regions are characterized by much higher oxygen abundances. H II nuclei systematically emit stronger low-ionization forbidden lines than disk H II regions, confirming a trend recognized by Kennicutt, Keel, & Blaha. We discuss several possibilities for the origin of the spectral variations.
Spitzer Observations of Supernova Remnants. II. Physical Conditions and Comparison with HH7 and HH54

We have studied the shock-excited molecular regions associated with four supernova remnants (SNRs)—IC443C, W28, W44, and 3C391—and two Herbig-Haro objects—HH7 and HH54—using Spitzer's Infrared Spectrograph (IRS). The physical conditions within the observed areas (roughly ~1' × 1' in size) are inferred from spectroscopic data obtained from IRS and from the Short and Long Wavelength Spectrometers on board the Infrared Space Observatory (ISO), together with photometric data from Spitzer's Infrared Array Camera. Adopting a power-law distribution for the gas temperature in the observed region, with the mass of gas at temperature T to T+dT assumed proportional to T –b dT, the H2 S(0) to S(7) spectral line maps obtained with IRS were used to constrain the gas density, yielding estimated densities n(H2) in the range of ~ (2-4)×103 cm–3. The excitation of H2 S(9) to S(12) and high-J CO pure rotational lines, however, require environments several times denser. The inconsistency among the best-fit densities estimated from different species can be explained by density fluctuations within the observed regions. The best-fit power-law index b is smaller than the value 3.8 predicted for a paraboloidal C-type bow shock, suggesting that the shock front has a "flatter" shape than that of a paraboloid. The best-fit parameters for SNRs and Herbig-Haro objects do not differ significantly between the two classes of sources, except that for the SNRs the ortho-to-para ratio (OPR) of hot gas (T> 1000 K) is close to the local thermal equilibrium value 3, while for HH7 and HH54 even the hottest gas exhibits an OPR smaller than 3; we interpret this difference as resulting from environmental differences between these classes of sources, molecular material near SNRs being subject to stronger photodissociation that results in faster para-to-ortho conversion. Finally, we mapped the physical parameters within the regions observed with IRS and found that the mid-lying H2 emissions—S(3) to S(5)—tend to trace the hot component of the gas, while the intensities of S(6) and S(7) are more sensitive to the density of the gas compared to S(3) to S(5).
Quasi-alternating links with small determinant

Quasi-alternating links of determinant 1, 2, 3 and 5 were previously classified by Greene and Teragaito, who showed that the only such links are two-bridge. In this paper, we extend this result by showing that all quasi-alternating links of determinant at most 7 are connected sums of two-bridge links, which is optimal since there are quasi-alternating links not of this form for all larger determinants. We achieve this by studying their branched double covers and characterising distance-one surgeries between lens spaces of small order, leading to a classification of formal L-spaces with order at most 7.
Correlation clustering based coalition formation for multi-robot task allocation

Due to the inherent complexity of many real world tasks and the limited capabilities of currently available robots in the market, it is almost impossible for a single robot to finish a complex task. Therefore several robots may need to form coalitions to complete such tasks. In this paper, we study the multi-robot coalition formation problem for instantaneous task allocation (IA) where a group of robots needs to be allocated to a set of tasks so that the tasks can be finished optimally. This is a well-known NP-hard problem. To tackle this notoriously difficult problem, we use a correlation clustering technique that enables us to bring similar robots together to form coalitions. This clustering is achieved by using a Linear Programming-based graph partitioning approach along with a region growing strategy. The algorithm presented in this paper is fast and efficient in allocating (near) optimal robot coalitions to tasks.
Amplitude equations for coupled electrostatic waves in the limit of weak instability

We consider the simplest instabilities involving multiple unstable electrostatic plasma waves corresponding to four-dimensional systems of mode amplitude equations. In each case, the coupled amplitude equations are derived up to third-order terms. The nonlinear coefficients are singular in the limit in which the linear growth rates vanish together. These singularities are analysed using techniques developed in previous studies of a single unstable wave. In addition to the singularities familiar from the single-mode problem, there are new singularities in coefficients coupling the modes. The new singularities are most severe when the two waves have the same linear phase velocity and satisfy the spatial resonance condition k 2 = 2k 1 . As a result, the short-wave mode saturates at a dramatically smaller amplitude than that predicted for the weak-growth-rate regime on the basis of single-mode theory. In contrast, the long-wave mode retains the single-mode scaling. If these resonance conditions are not satisfied then both modes retain their single-mode scaling and saturate at comparable amplitudes.
Evaluating and Rewarding Teamwork Using Cooperative Game Abstractions

Can we predict how well a team of individuals will perform together? How should individuals be rewarded for their contributions to the team performance? Cooperative game theory gives us a powerful set of tools for answering these questions: the Characteristic Function (CF) and solution concepts like the Shapley Value (SV). There are two major difficulties in applying these techniques to real world problems: first, the CF is rarely given to us and needs to be learned from data. Second, the SV is combinatorial in nature. We introduce a parametric model called cooperative game abstractions (CGAs) for estimating CFs from data. CGAs are easy to learn, readily interpretable, and crucially allow linear-time computation of the SV. We provide identification results and sample complexity bounds for CGA models as well as error bounds in the estimation of the SV using CGAs. We apply our methods to study teams of artificial RL agents as well as real world teams from professional sports.
Multilinear spherical maximal function

In dimensions $n\ge 2$ we obtain $L^{p_1}(\mathbb R^n) \times\dots\times L^{p_m}(\mathbb R^n)$ to $L^p(\mathbb R^n)$ boundedness for the multilinear spherical maximal function in the largest possible open set of indices and we provide counterexamples that indicate the optimality of our results. Moreover, we obtain weak type and Lorentz space estimates as well as counterexamples in the endpoint cases.
Symmetry analysis and exact solutions of one class of (1 + 3)-dimensional boundary-value problems of the Stefan type

We present the group classification of one class of (1 + 3)-dimensional nonlinear boundary-value problems of the Stefan type that simulate the processes of melting and evaporation of metals. The results obtained are used for the construction of the exact solution of one boundary-value problem from the class under study.
The High-Resolution X-Ray Spectrum of SS 433 Using the Chandra HETGS

We present observations of SS 433 using the Chandra High Energy Transmission Grating Spectrometer. Many emission lines of highly ionized elements are detected with relativistic blue and red Doppler shifts. The lines are measurably broadened to 1700 km s-1 (FWHM), and the widths do not depend significantly on the characteristic emission temperature, suggesting that the emission occurs in a freely expanding region of constant collimation with an opening angle of 123 ± 006. The blueshifts of lines from low-temperature gas are the same as those of high-temperature gas within the uncertainties, again indicating that the hottest gas we observe to emit emission lines is already at terminal velocity. This velocity is 0.2699 ± 0.0007c, which is larger than the velocity inferred from optical emission lines by 2920 ± 440 km s-1. Fits to the emission-line fluxes give a range of temperatures in the jet from 5 × 106 to 1 × 108 K. We derive the emission measure as a function of temperature for a four-component model that fits the line flux data. Using the density-sensitive Si XIII triplet, the characteristic electron density is 1014 cm-3, where the gas temperature is about 1.3 × 107 K. Based on an adiabatic expansion model of the jet and a distance of 4.85 kpc, the electron densities drop from ~2 × 1015 to 4 × 1013 cm-3 at distances of (2-20) × 1010 cm from the apex of the cone that bounds the flow. The radius of the base of the visible jet is estimated to be ~108 cm, and the mass outflow rate is 1.5 × 10-7 M☉ yr-1. The kinetic power is 3.2 × 1038 ergs s-1, which is 1000 times larger than the unabsorbed 2-10 keV X-ray luminosity. The bremsstrahlung emission associated with the lines can account for the entire continuum; we see no direct evidence for an accretion disk. The image from zeroth order shows extended emission at a scale of ~2'', aligned in the general direction of the radio jets.
HIGH-ENERGY FACTORIZATION AND EVOLUTION WITH IMPROVED KINEMATICS

The high-energy factorization and the associated B-JIMWLK or BK evolution equations are presented, using the example of DIS structure functions. The necessity of taking gluon saturation into account is discussed, and also the various approximations underlying high-energy factorization. The appearance of large NLL corrections in such a framework with or without gluon saturation is recalled, and their physical origin is explained. Finally, old and new results are presented about the resummation of some of those large corrections, related to kinematical approximations.
Light-cone quantization of gauge fields

Light-cone quantization of gauge field theory is considered. With a careful treatment of the relevant degrees of freedom and where they must be initialized, the results obtained in equal-time quantization are recovered, in particular the Mandelstam-Leibbrandt form of the gauge field propagator. Some aspects of the “discretized” light-cone quantization of gauge fields are discussed.
A new formula describing the scaffold structure of spiral galaxies

We describe a new formula capable of quantitatively characterizing the Hubble sequence of spiral galaxies including grand design and barred spirals. Special shapes such as ring galaxies with inward and outward arms are also described by the analytic continuation of the same formula. The formula is r(φ) =A/log [B tan (φ/2N)]. This function intrinsically generates a bar in a continuous, fixed relationship relative to an arm of arbitrary winding sweep. A is simply a scale parameter while B, together with N, determines the spiral pitch. Roughly, greater N results in tighter winding. Greater B results in greater arm sweep and smaller bar/bulge, while smaller B fits larger bar/bulge with a sharper bar/arm junction. Thus B controls the ‘bar/bulge-to-arm’ size, while N controls the tightness much like the Hubble scheme. The formula can be recast in a form dependent only on a unique point of turnover angle of pitch – essentially a one-parameter fit, aside from a scalefactor. The recast formula is remarkable and unique in that a single parameter can define a spiral shape with either constant or variable pitch capable of tightly fitting Hubble types from grand design spirals to late-type large barred galaxies. We compare the correlation of our pitch parameter to Hubble type with that of the traditional logarithmic spiral for 21 well-shaped galaxies. The pitch parameter of our formula produces a very tight correlation with ideal Hubble type suggesting it is a good discriminator compared to logarithmic pitch, which shows poor correlation here similar to previous works. Representative examples of fitted galaxies are shown.
Formulas for Radial Transport in Protoplanetary Disks

The quantification of the radial transport of gaseous species and solid particles is important to many applications in protoplanetary disk evolution. An especially important example is determining the location of the water snow lines in a disk, which requires computing the rates of outward radial diffusion of water vapor and the inward radial drift of icy particles; however, the application is generalized to evaporation fronts of all volatiles. We review the relevant formulas using a uniform formalism. This uniform treatment is necessary because the literature currently contains at least six mutually exclusive treatments of radial diffusion of gas, only one of which is correct. We derive the radial diffusion equations from first principles using Fick's law. For completeness, we also present the equations for radial transport of particles. These equations may be applied to studies of diffusion of gases and particles in protoplanetary and other accretion disks.
VIBRATIONALLY EXCITED MOLECULAR HYDROGEN NEAR HERSCHEL 36

We present the first high resolution UV spectra toward Herschel 36, a Trapezium-like system of high-mass stars contained within the Lagoon Nebula (M8, NGC 6523). The spectra reveal extreme rovibrational excitation of molecular hydrogen in material at a single velocity or very small range of velocities, with this component presumably lying near the star system and undergoing fluorescent excitation. The overall H2 excitation is similar to, but apparently larger than, that seen toward HD 37903 which previously showed the largest vibrationally excited H2 column densities seen in UV absorption spectra. While the velocities of the highly excited H2 lines are consistent within each observation, it appears that they underwent a ~60 km s–1 redshift during the 3.6 yr between observations. In neither case does the velocity of the highly excited material match the velocity of the bulk of the line-of-sight material which appears to mostly be in the foreground of M8. Recent work shows unusually excited CH and CH+ lines and several unusually broad diffuse interstellar bands toward Herschel 36. Along with the H2 excitation, all of these findings appear to be related to the extreme environment within ~0.1 pc of the massive young stellar system.
Simplicial Ricci Flow

We construct a discrete form of Hamilton’s Ricci flow (RF) equations for a d-dimensional piecewise flat simplicial geometry, $${{\mathcal S}}$$ . These new algebraic equations are derived using the discrete formulation of Einstein’s theory of general relativity known as Regge calculus. A Regge–Ricci flow (RRF) equation can be associated to each edge, l, of a simplicial lattice. In defining this equation, we find it convenient to utilize both the simplicial lattice $${{\mathcal S}}$$ and its circumcentric dual lattice, $${{\mathcal S}^*}$$ . In particular, the RRF equation associated to l is naturally defined on a d-dimensional hybrid block connecting l with its (d−1)-dimensional circumcentric dual cell, l *. We show that this equation is expressed as the proportionality between (1) the simplicial Ricci tensor, Rc l , associated with the edge $${\ell\in{\mathcal S}}$$ , and (2) a certain volume weighted average of the fractional rate of change of the edges, $${\lambda\in \ell^*}$$ , of the circumcentric dual lattice, $${{\mathcal S}^*}$$ , that are in the dual of l. The inherent orthogonality between elements of $${\mathcal S}$$ and their duals in $${{\mathcal S}^*}$$ provide a simple geometric representation of Hamilton’s RF equations. In this paper we utilize the well established theories of Regge calculus, or equivalently discrete exterior calculus, to construct these equations. We solve these equations for a few illustrative examples.
Predictive analysis for social processes II: Predictability and warning analysis

This two-part paper presents a new approach to predictive analysis for social processes. Part I identifies a class of social processes, called positive externality processes, which are both important and difficult to predict, and introduces a multi-scale, stochastic hybrid system modeling framework for these systems. In Part II of the paper we develop a systems theory-based, computationally tractable approach to predictive analysis for these systems. Among other capabilities, this analytic methodology enables assessment of process predictability, identification of measurables which have predictive power, discovery of reliable early indicators for events of interest, and robust, scalable prediction. The potential of the proposed approach is illustrated through case studies involving online markets, social movements, and protest behavior.
LOCO Codes: Lexicographically-Ordered Constrained Codes

Line codes make it possible to mitigate interference, to prevent short pulses, and to generate streams of bipolar signals with no direct-current (DC) power content through balancing. They find application in magnetic recording (MR) devices, in Flash devices, in optical recording devices, and in some computer standards. This paper introduces a new family of fixed-length, binary constrained codes, named lexicographically-ordered constrained codes (LOCO codes), for bipolar non-return-to-zero signaling. LOCO codes are capacity-achieving, the lexicographic indexing enables simple, practical encoding and decoding, and this simplicity is demonstrated through analysis of circuit complexity. LOCO codes are easy to balance, and their inherent symmetry minimizes the rate loss with respect to unbalanced codes having the same constraints. Furthermore, LOCO codes that forbid certain patterns can be used to alleviate inter-symbol interference in MR systems and inter-cell interference in Flash systems. Numerical results demonstrate a gain of up to 10% in rate achieved by LOCO codes with respect to other practical constrained codes, including run-length-limited codes, designed for the same purpose. Simulation results suggest that it is possible to achieve a channel density gain of about 20% in MR systems by using a LOCO code to encode only the parity bits, limiting the rate loss, of a low-density parity-check code before writing.
The Highly Eccentric Pre-Main-Sequence Spectroscopic Binary RX J0529.3+1210

The young system RX J0529.3+1210 was initially identified as a single-lined spectroscopic binary. Using high-resolution infrared spectra, acquired with NIRSPEC on Keck II, we measured radial velocities for the secondary. The method of using the infrared regime to convert single-lined spectra into double-lined spectra, and derive the mass ratio for the binary system, has been successfully used for a number of young, low-mass binaries. For RX J0529.3+1210, a long-period (462 days) and highly eccentric (0.88) binary system, we determine the mass ratio to be 0.78 ± 0.05 using the infrared double-lined velocity data alone, and 0.73 ± 0.23 combining visible light and infrared data in a full orbital solution. The large uncertainty in the latter is the result of the sparse sampling in the infrared and the high eccentricity: the stars do not have a large velocity separation during most of their ~1.3 yr orbit. A mass ratio close to unity, consistent with the high end of the 1σ uncertainty for this mass ratio value, is inconsistent with the lack of a visible light detection of the secondary component. We outline several scenarios for a color difference in the two stars, such as one heavily spotted component, higher-order multiplicity, or a unique evolutionary stage, favoring detection of only the primary star in visible light, even in a mass ratio ~1 system. However, the evidence points to a lower ratio. Although RX J0529.3+1210 exhibits no excess at near-infrared wavelengths, a small 24 μm excess is detected, consistent with circumbinary dust. The properties of this binary and its membership in λ Ori versus a new nearby stellar moving group at ~90 pc are discussed. We speculate on the origin of this unusual system and on the impact of such high eccentricity, the largest observed in a pre-main-sequence double-lined system to date, on the potential for planet formation.
143 GHz BRIGHTNESS MEASUREMENTS OF URANUS, NEPTUNE, AND OTHER SECONDARY CALIBRATORS WITH BOLOCAM BETWEEN 2003 AND 2010

Bolocam began collecting science data in 2003 as the long-wavelength imaging camera at the Caltech Submillimeter Observatory. The planets, along with a handful of secondary calibrators, have been used to determine the flux calibration for all of the data collected with Bolocam. Uranus and Neptune stand out as the only two planets that are bright enough to be seen with high signal-to-noise in short integrations without saturating the standard Bolocam readout electronics. By analyzing all of the 143 GHz observations made with Bolocam between 2003 and 2010, we find that the brightness ratio of Uranus to Neptune is 1.027 ± 0.006, with no evidence for any variations over that period. Including previously published results at ≃ 150 GHz, we find a brightness ratio of 1.029 ± 0.006 with no evidence for time variability over the period 1983-2010. Additionally, we find no evidence for time variability in the brightness ratio of either Uranus or Neptune to the ultracompact H II region G34.3 or the protostellar source NGC 2071IR. Using recently published Wilkinson Microwave Anisotropy Probe results we constrain the absolute 143 GHz brightness of both Uranus and Neptune to ≃ 3%. Finally, we present ≃ 3% absolute 143 GHz peak flux density values for the ultracompact H II regions G34.3 and K3-50A and the protostellar source NGC 2071IR.
An EL-labeling of the subgroup lattice

In a 2001 paper, Shareshian conjectured that the subgroup lattice of a finite, solvable group has an EL-labeling. We construct such a labeling and verify that our labeling has the expected properties.
Evaluating Single-Cell Cluster Stability Using The Jaccard Similarity Index.

Motivation One major goal of single-cell RNA sequencing (scRNAseq) experiments is to identify novel cell types. With increasingly large scRNAseq datasets, unsupervised clustering methods can now produce detailed catalogues of transcriptionally distinct groups of cells in a sample. However, the interpretation of these clusters is challenging for both technical and biological reasons. Popular clustering algorithms are sensitive to parameter choices, and can produce different clustering solutions with even small changes in the number of principal components used, the k nearest neighbor, and the resolution parameters, among others. Results Here, we present a set of tools to evaluate cluster stability by subsampling, which can guide parameter choice and aid in biological interpretation. The R package scclusteval and the accompanying Snakemake workflow implement all steps of the pipeline: subsampling the cells, repeating the clustering with Seurat, and estimation of cluster stability using the Jaccard similarity index and providing rich visualizations. Availability R package scclusteval: https://github.com/crazyhottommy/scclusteval Snakemake workflow: https://github.com/crazyhottommy/pyflow_seuratv3_parameter Tutorial: https://crazyhottommy.github.io/EvaluateSingleCellClustering/. Supplementary information Supplementary data are available at Bioinformatics online.
Key role of lattice symmetry in the metal-insulator transition of NdNiO3 films

Bulk NdNiO3 exhibits a metal-to-insulator transition (MIT) as the temperature is lowered that is also seen in tensile strained films. In contrast, films that are under a large compressive strain typically remain metallic at all temperatures. To clarify the microscopic origins of this behavior, we use position averaged convergent beam electron diffraction in scanning transmission electron microscopy to characterize strained NdNiO3 films both above and below the MIT temperature. We show that a symmetry lowering structural change takes place in case of the tensile strained film, which undergoes an MIT, but is absent in the compressively strained film. Using space group symmetry arguments, we show that these results support the bond length disproportionation model of the MIT in the rare-earth nickelates. Furthermore, the results provide insights into the non-Fermi liquid phase that is observed in films for which the MIT is absent.
Optimal Correlation Estimators for Quantized Signals

Using a maximum-likelihood criterion, we derive optimal correlation strategies for signals with and without digitization. We assume that the signals are drawn from zero-mean Gaussian distributions, as is expected in radio-astronomical applications, and we present correlation estimators both with and without a priori knowledge of the signal variances. We demonstrate that traditional estimators of correlation, which rely on averaging products, exhibit large and paradoxical noise when the correlation is strong. However, we also show that these estimators are fully optimal in the limit of vanishing correlation. We calculate the bias and noise in each of these estimators and discuss their suitability for implementation in modern digital correlators.