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Abstract The Anacardiaceae are a characteristic angiosperm family of the Neotropics where they comprise ~32 genera and 200 species (~80 genera and 800 species globally). Among Neotropical Anacardiaceae genera, Schinus has the greatest species richness with 42 species distributed from tropical latitudes of Brazil and Peru south to the temperate steppe, matorral, and Valdivian temperate forest communities of Patagonia. Previous studies have found some anatomical and morphological leaf traits (e.g. simple vs. compound leaf organization) useful in characterizing lineages within Schinus, but also document traits that are homoplastic within the genus (e.g. stomatal distribution) and convergent among Schinus and its close relatives Lithrea and Mauria (e.g. mesophyll arrangement). Here, we present a survey of leaf cuticular traits in 53 species of Schinus and its closest relatives Lithrea, Mauria, and Euroschinus based on characters observed with scanning electron and optical light microscopy. We use ordinated Bray–Curtis distances based on 18 characters and 2D nonmetric multidimensional scaling to show that cuticular morphology resolves the three most diverse genera, Euroschinus, Mauria, and Schinus, but does not resolve intrageneric sections of Schinus. We propose that a distinctive acuminate gland type occurring only within Euroschinus may constitute a potential synapomorphy for this genus. Within Schinus, we find inconsistency in stomatal distribution among specimens of a single species, among species of a single section, and between sections of the genus, and suggest that current evidence is insufficient to implicate either phenotypic plasticity or homoplasy as the causative mechanism of this variation. 

We present SERBERUS, the first comprehensive mitigation for hardening constant-time (CT) code against Spectre attacks (involving the PHT, BTB, RSB, STL, and/or PSF speculation primitives) on existing hardware. SERBERUS is based on three insights. First, some hardware control-flow integrity (CFI) protections restrict transient control-flow to the extent that it may be comprehensively considered by software analyses. Second, conformance to the accepted CT code discipline permits two code patterns that are unsafe in the post-Spectre era. Third, once these code patterns are addressed, all Spectre leakage of secrets in CT programs can be attributed to one of four classes of taint primitives—instructions that can transiently assign a secret value to a publicly-typed register. We evaluate SERBERUS on cryptographic primitives in the OPENSSL, LIBSODIUM, and HACL* libraries. SERBERUS introduces 21.3% runtime overhead on average, compared to 24.9% for the next closest state-of-the-art software mitigation, which is less secure. 

We consider a new class of multi-period network interdiction problems, where interdiction and restructuring decisions are decided upon before the network is operated and implemented throughout the time horizon.We discuss how we apply this new problem to disrupting domestic sex trafficking networks, and introduce a variant where a second cooperating attacker has the ability to interdict victims and prevent the recruitment of prospective victims. This problem is modeled as a bilevel mixed integer linear program (BMILP), and is solved using column-and-constraint generation with partial information. We also simplify the BMILP when all interdictions are implemented before the network is operated. Modeling-based augmentations are proposed to significantly improve the solution time in a majority of instances tested. We apply our method to synthetic domestic sex trafficking networks, and discuss policy implications from our model. In particular, we show how preventing the recruitment of prospective victims may be as essential to disrupting sex trafficking as interdicting existing participants. 

This panel will discuss the role of different knowledge artifacts in creating, maintaining, and circulating knowledge within the engineering education community. The past decade has seen a significant increase in the venues available for sharing engineering education research and as the field grows and builds more knowledge, it is equally important to also take stock of prior work and of strategies to create novelty. Within this context, what is the role of different knowledge encapsulating artifacts and why do those who engage with creating these artifacts do so? In this panel we touch upon these issues while taking stock of the knowledge base in the field. We will also discuss what the future of knowledge creation in the field might look like given the move towards open access online publications as the primary form of knowledge circulation. Finally, in the post-COVID context, what will and should be the role of in-person events in this process. In terms of equity of participation, what potential avenues are available? 

Abstract SPPARKS is an open-source parallel simulation code for developing and running various kinds of on-lattice Monte Carlo models at the atomic or meso scales. It can be used to study the properties of solid-state materials as well as model their dynamic evolution during processing. The modular nature of the code allows new models and diagnostic computations to be added without modification to its core functionality, including its parallel algorithms. A variety of models for microstructural evolution (grain growth), solid-state diffusion, thin film deposition, and additive manufacturing (AM) processes are included in the code. SPPARKS can also be used to implement grid-based algorithms such as phase field or cellular automata models, to run either in tandem with a Monte Carlo method or independently. For very large systems such as AM applications, the Stitch I/O library is included, which enables only a small portion of a huge system to be resident in memory. In this paper we describe SPPARKS and its parallel algorithms and performance, explain how new Monte Carlo models can be added, and highlight a variety of applications which have been developed within the code.