2,334 research outputs found
The Shape and Dimensionality of Phylogenetic Tree-Space Based on Mitochondrial Genomes
Phylogenetic analyses of large and diverse data sets generally result in large sets of competing phylogenetic trees. Consensus tree methods used to summarize sets of competing trees discard important information regarding the similarity and distribution of competing trees. A more fine grain approach is to use a dimensionality reduction method to project tree-to-tree distances in 2D or 3D space. In this study, we systematically evaluate the performance of several nonlinear dimensionality reduction (NLDR) methods on tree-to-tree distances obtained from independent nonparametric bootstrap analyses of genes from three mid- to large-sized mitochondrial genome alignments.

MC: Subaru and Hubble Space Telescope Weak-Lensing Analysis of the Double Radio Relic Galaxy Cluster PLCK G287.0+32.9
The second most significant detection of the Planck Sunyaev Zel'dovich
survey, PLCK~G287.0+32.9 () boasts two similarly bright radio relics
and a radio halo. One radio relic is located kpc northwest of the
X-ray peak and the other Mpc to the southeast. This large difference
suggests that a complex merging scenario is required. A key missing puzzle for
the merging scenario reconstruction is the underlying dark matter distribution
in high resolution. We present a joint Subaru Telescope and {\it Hubble Space
Telescope} weak-lensing analysis of the cluster. Our analysis shows that the
mass distribution features four significant substructures. Of the
substructures, a primary cluster of mass
$M_{200\text{c}}=1.59^{+0.25}_{-0.22}\times 10^{15} \ h^{-1}_{70} \
\text{M}_{\odot}M_{200\text{c}}=1.16^{+0.15}_{-0.13}\times 10^{14} \ h^{-1}_{70} \
\text{M}_{\odot}\sim 400\sim 2M_{200\text{c}}=1.68^{+0.22}_{-0.20}\times
10^{14} \ h^{-1}_{70} \ \text{M}_{\odot}M_{200\text{c}}=1.87^{+0.24}_{-0.22}\times 10^{14} \ h^{-1}_{70} \
\text{M}_{\odot}$, is northwest of the X-ray peak and beyond the NW radio
relic.Comment: 19 pages, 14 figures; Accepted to Ap
Stabilized Finite Elements in FUN3D
A Streamlined Upwind Petrov-Galerkin (SUPG) stabilized finite-element discretization has been implemented as a library into the FUN3D unstructured-grid flow solver. Motivation for the selection of this methodology is given, details of the implementation are provided, and the discretization for the interior scheme is verified for linear and quadratic elements by using the method of manufactured solutions. A methodology is also described for capturing shocks, and simulation results are compared to the finite-volume formulation that is currently the primary method employed for routine engineering applications. The finite-element methodology is demonstrated to be more accurate than the finite-volume technology, particularly on tetrahedral meshes where the solutions obtained using the finite-volume scheme can suffer from adverse effects caused by bias in the grid. Although no effort has been made to date to optimize computational efficiency, the finite-element scheme is competitive with the finite-volume scheme in terms of computer time to reach convergence
Wind-Reprocessed Transients from Stellar-mass Black Hole Tidal Disruption Events
Tidal disruptions of stars by stellar-mass black holes are expected to occur
frequently in dense star clusters. Building upon previous studies that
performed hydrodynamic simulations of these encounters, we explore the
formation and long-term evolution of the thick, super-Eddington accretion disks
formed. We build a disk model that includes fallback of material from the tidal
disruption, accretion onto the black hole, and disk mass losses through winds
launched in association with the super-Eddington flow. We demonstrate that
bright transients are expected when radiation from the central engine powered
by accretion onto the black hole is reprocessed at large radii by the
optically-thick disk wind. By combining hydrodynamic simulations of these
disruption events with our disk+wind model, we compute light curves of these
wind-reprocessed transients for a wide range of stellar masses and encounter
penetration depths. We find typical peak bolometric luminosities of roughly
erg/s (depending mostly on accretion physics parameters) and
temperatures of roughly K, suggesting peak emission in the
ultraviolet/blue bands. We predict all-sky surveys such as the Vera Rubin
Observatory and ULTRASAT will detect up to thousands of these events per year
in dense star clusters out to distances of several Gpc.Comment: 16 Pages, 13 figures, 2 tables. Accepted for publication in MNRA
Preventing Supply Chain Vulnerabilities in Java with a Fine-Grained Permission Manager
Integrating third-party packages accelerates modern software engineering, but
introduces the risk of software supply chain vulnerabilities. Vulnerabilities
in applications' dependencies are being exploited worldwide. Often, these
exploits leverage features that are present in a package, yet unneeded by an
application. Unfortunately, the current generation of permission managers, such
as SELinux, Docker containers, and the Java Security Manager, are too
coarse-grained to usefully support engineers and operators in mitigating these
vulnerabilities. Current approaches offer permissions only at the application's
granularity, lumping legitimate operations made by safe packages with
illegitimate operations made by exploited packages. This strategy does not
reflect modern engineering practice. we need a permission manager capable of
distinguishing between actions taken by different packages in an application's
supply chain.
In this paper, we describe Next-JSM, the first fine-grained ("supply chain
aware") permission manager for Java applications. Next-JSM supports permission
management at package-level granularity. Next-JSM faces three key challenges:
operating on existing JVMs and without access to application or package source
code, minimizing performance overhead in applications with many packages, and
helping operators manage finer-grained permissions. We show that these
challenges can be addressed through bytecode rewriting; appropriate data
structures and algorithms; and an expressive permission notation plus automated
tooling to establish default permission. In our evaluation, we report that
Next-JSM mitigates 11 of the 12 package vulnerabilities we evaluated and incurs
an average 2.72% overhead on the Dacapobench benchmark. Qualitatively, we argue
that Next-JSM addresses the shortcomings of the (recently deprecated) Java
Security Manager (JSM).Comment: 15 pages, 5 figures, 5 table
Basic Features of a Cell Electroporation Model: Illustrative Behavior for Two Very Different Pulses
Science increasingly involves complex modeling. Here we describe a model for cell electroporation in which membrane properties are dynamically modified by poration. Spatial scales range from cell membrane thickness (5 nm) to a typical mammalian cell radius (10 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\upmu\end{document}m), and can be used with idealized and experimental pulse waveforms. The model consists of traditional passive components and additional active components representing nonequilibrium processes. Model responses include measurable quantities: transmembrane voltage, membrane electrical conductance, and solute transport rates and amounts for the representative ālongā and āshortā pulses. The long pulseā1.5 kV/cm, 100 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\upmu\end{document}sāevolves two pore subpopulations with a valley at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}5 nm, which separates the subpopulations that have peaks at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}1.5 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}12 nm radius. Such pulses are widely used in biological research, biotechnology, and medicine, including cancer therapy by drug delivery and nonthermal physical tumor ablation by causing necrosis. The short pulseā40 kV/cm, 10 nsācreates 80-fold more pores, all small (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}3 nm; \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}1 nm peak). These nanosecond pulses ablate tumors by apoptosis. We demonstrate the modelās responses by illustrative electrical and poration behavior, and transport of calcein and propidium. We then identify extensions for expanding modeling capability. Structure-function results from MD can allow extrapolations that bring response specificity to cell membranes based on their lipid composition. After a pulse, changes in pore energy landscape can be included over seconds to minutes, by mechanisms such as cell swelling and pulse-induced chemical reactions that slowly alter pore behavior. Electronic supplementary material The online version of this article (doi:10.1007/s00232-014-9699-z) contains supplementary material, which is available to authorized users
- ā¦