Core-Collapse Supernova Simulations including Neutrino Interactions from the Virial EOS

Core-collapse supernova explosions are driven by a central engine that converts a small fraction of the gravitational binding energy released during core collapse to outgoing kinetic energy. The suspected mode for this energy conversion is the neutrino mechanism, where a fraction of the neutrinos emitted from the newly formed protoneutron star are absorbed by and heat the matter behind the supernova shock. Accurate neutrino-matter interaction terms are crucial for simulating these explosions. In this proceedings for IAUS 331, SN 1987A, 30 years later, we explore several corrections to the neutrino-nucleon scattering opacity and demonstrate the effect on the dynamics of the core-collapse supernova central engine via two dimensional neutrino-radiation-hydrodynamics simulations. Our results reveal that the explosion properties are sensitive to corrections to the neutral-current scattering cross section at the 10-20% level, but only for densities at or above $\sim 10^{12}$ g cm$^{-3}$Comment: 6 pages, 3 figures, appears in Proc. IAU Symposium 331, SN 1987A, 30 years later - Cosmic Rays and Nuclei from Supernovae and Their Aftermath

Phase resetting reveals network dynamics underlying a bacterial cell cycle

Genomic and proteomic methods yield networks of biological regulatory interactions but do not provide direct insight into how those interactions are organized into functional modules, or how information flows from one module to another. In this work we introduce an approach that provides this complementary information and apply it to the bacterium Caulobacter crescentus, a paradigm for cell-cycle control. Operationally, we use an inducible promoter to express the essential transcriptional regulatory gene ctrA in a periodic, pulsed fashion. This chemical perturbation causes the population of cells to divide synchronously, and we use the resulting advance or delay of the division times of single cells to construct a phase resetting curve. We find that delay is strongly favored over advance. This finding is surprising since it does not follow from the temporal expression profile of CtrA and, in turn, simulations of existing network models. We propose a phenomenological model that suggests that the cell-cycle network comprises two distinct functional modules that oscillate autonomously and couple in a highly asymmetric fashion. These features collectively provide a new mechanism for tight temporal control of the cell cycle in C. crescentus. We discuss how the procedure can serve as the basis for a general approach for probing network dynamics, which we term chemical perturbation spectroscopy (CPS)

A block α\alpha-circulant based preconditioned MINRES method for wave equations

In this work, we propose an absolute value block $\alpha$-circulant preconditioner for the minimal residual (MINRES) method to solve an all-at-once system arising from the discretization of wave equations. Since the original block $\alpha$-circulant preconditioner shown successful by many recently is non-Hermitian in general, it cannot be directly used as a preconditioner for MINRES. Motivated by the absolute value block circulant preconditioner proposed in [E. McDonald, J. Pestana, and A. Wathen. SIAM J. Sci. Comput., 40(2):A1012-A1033, 2018], we propose an absolute value version of the block $\alpha$-circulant preconditioner. Our proposed preconditioner is the first Hermitian positive definite variant of the block $\alpha$-circulant preconditioner, which fills the gap between block $\alpha$-circulant preconditioning and the field of preconditioned MINRES solver. The matrix-vector multiplication of the preconditioner can be fast implemented via fast Fourier transforms. Theoretically, we show that for properly chosen $\alpha$ the MINRES solver with the proposed preconditioner has a linear convergence rate independent of the matrix size. To the best of our knowledge, this is the first attempt to generalize the original absolute value block circulant preconditioner in the aspects of both theory and performance. Numerical experiments are given to support the effectiveness of our preconditioner, showing that the expected optimal convergence can be achieved

No Peeking: Addressing Pretextual Inspection Demands by Competitor-Affiliated Shareholders

This article exposes how Delaware private companies are vulnerable to pretextual inspections under the guise of valuation by shareholders who are affiliated with competitors of the companies. The Delaware Court of Chancery’s 2020 decision in Woods v. Sahara Enterprises, Inc., which deviated from established law by switching the initial burden of proof of the shareholder’s motive to the target company, exacerbated this vulnerability. This article argues for reversing that decision and proposes changes in multiple areas of law to help companies fend off prying competitors who abuse statutory shareholder inspection rights for unfair advantages in competition

Temperature-Aware Leakage Minimization Techniques for Real-Time Systems

In this paper, we study the interdependencies between system's leakage and on-chip temperature. We show that the temperature variation caused by on-chip heat accumulation has a large impact in estimating the system's leakage energy. More importantly, we propose an online temperature-aware leakage minimization technique to demonstrate how to incorporate the temperature information to reduce energy consumption at real time. The basic idea is to run when the system is cool and the workload is high and to put the system to sleep when it is hot and the workload is light. The online algorithm has low run-time complexity and achieves significant leakage energy saving. In fact, we are able to get about 25% leakage reduction on both real life and artificial benchmarks. Comparing to our optimal offline algorithm, the above online algorithm provides similar energy savings with similar decisions on how to put the system to sleep and how to wake it up. Finally, our temperature-aware leakage minimization techniques can be combined with existing DVS methods to improve the total energy efficiency by further saving on leakage

Soto\u27s True Earth Market Optimization

Soto’s True Earth Market is a new organic market startup which is located in a historical facility in the small town of Cambria. The new owner of Soto’s Andre Ponce has a vision to create a community revolved around local organic foods and sustainability. Since Soto’s is still in the initial startup phase there is a large amount of room for optimization and redesign in order to create a solid customer foundation. Andre presented several opportunities for improvement to the team. With a time constraint of solely two quarters the project team decided to provide the following: ● Old and new deli/smoothie department layouts ● Old and new facility layouts ● Economic analysis of equipment purchases The overall objective of this project was to provide a concrete layout and operating procedure for the overall facility of Soto’s market along with an evaluation of potential equipment purchases for their food service station. The constraints of the project was anything excluded from the deliverables and any further redesign outside of the main shopping area of Soto’s market. In the following report the overall background of the project is described in more detail along with the project scope for optimizing Soto’s. Also, an in depth literature review is included to provide a greater insight on how to approach and achieve the overall goal of the project. Through all the research that the project team obtained a proposed methodology for each deliverable was created to streamline the next steps of the project. Included along with the proposed methodology is also proposed schedule to be followed in order to efficiently complete the project

Assessing the Impact of Family Status, Family Cohesion, and Acculturation on Youth Violence Among Immigrant Latinos

Background/Objectives: Latino youth violence is an emerging public health concern. The objective is to assess the impact of family status, family cohesion, and acculturation on youth violence among Latino immigrants in Langley Park, MD compared with a control community in Culmore, VA. Methods: Constructs were generated from survey questions to represent family support and cohesion, acculturation, and youth violence. Bivariate and multivariate regression analyses were modeled to evaluate the relationships between family support and cohesion, acculturation, and violence, after adjusting for confounders. Results: After controlling for covariates, family support consistently reduced victimization (PE = ‐0.02, SE = 0.01, t = ‐2.64, p‐value = 0.0085); increased non‐violence attitudes and beliefs (PE = 0.32, SE = 0.05, t = 6.17, p‐value = Conclusions: Family support is associated with reduced violence engagement and risk behaviors among Latino youth. Results will inform the development and implementation of future youth violence prevention programs among ethnic minorities and immigrants