12,505 research outputs found
Design of an integrated airframe/propulsion control system architecture
The design of an integrated airframe/propulsion control system architecture is described. The design is based on a prevalidation methodology that uses both reliability and performance. A detailed account is given for the testing associated with a subset of the architecture and concludes with general observations of applying the methodology to the architecture
Minimal Interspecies Interaction Adjustment (MIIA): Inference of Neighbor-Dependent Interactions in Microbial Communities
An intriguing aspect in microbial communities is that pairwise interactions can be influenced by neighboring species. This creates context dependencies for microbial interactions that are based on the functional composition of the community. Context dependent interactions are ecologically important and clearly present in nature, yet firmly established theoretical methods are lacking from many modern computational investigations. Here, we propose a novel network inference method that enables predictions for interspecies interactions affected by shifts in community composition and species populations. Our approach first identifies interspecies interactions in binary communities, which is subsequently used as a basis to infer modulation in more complex multi-species communities based on the assumption that microbes minimize adjustments of pairwise interactions in response to neighbor species. We termed this rule-based inference minimal interspecies interaction adjustment (MIIA). Our critical assessment of MIIA has produced reliable predictions of shifting interspecies interactions that are dependent on the functional role of neighbor organisms. We also show how MIIA has been applied to a microbial community composed of competing soil bacteria to elucidate a new finding that – in many cases – adding fewer competitors could impose more significant impact on binary interactions. The ability to predict membership-dependent community behavior is expected to help deepen our understanding of how microbiomes are organized in nature and how they may be designed and/or controlled in the future
Opaque or transparent? A link between neutrino optical depths and the characteristic duration of short gamma-ray bursts
Cosmological gamma ray bursts (GRBs) are thought to occur from violent
hypercritical accretion onto stellar mass black holes, either following core
collapse in massive stars or compact binary mergers. This dichotomy may be
reflected in the two classes of bursts having different durations. Dynamical
calculations of the evolution of these systems are essential if one is to
establish characteristic, relevant timescales. We show here for the first time
the result of dynamical simulations, lasting approximately one second, of
post--merger accretion disks around black holes, using a realistic equation of
state and considering neutrino emission processes. We find that the inclusion
of neutrino optical depth effects produces important qualitative temporal and
spatial transitions in the evolution and structure of the disk, which may
directly reflect upon the duration and variability of short GRBs.Comment: Accepted for publication in ApJ Letter
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