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Given m users (voters), where each user casts her preference for a single item (candidate) over n items (candidates) as a ballot, the preference aggregation problem returns k items (candidates) that have the k highest number of preferences (votes). Our work studies this problem considering complex fairness constraints that have to be satisfied via proportionate representations of different values of the group protected attribute(s) in the top- k results. Precisely, we study the margin finding problem under single ballot substitutions , where a single substitution amounts to removing a vote from candidate i and assigning it to candidate j and the goal is to minimize the number of single ballot substitutions needed to guarantee that the top-k results satisfy the fairness constraints. We study several variants of this problem considering how top- k fairness constraints are defined, (i) MFBinaryS and MFMultiS are defined when the fairness (proportionate representation) is defined over a single, binary or multivalued, protected attribute, respectively; (ii) MF-Multi2 is studied when top- k fairness is defined over two different protected attributes; (iii) MFMulti3+ investigates the margin finding problem, considering 3 or more protected attributes. We study these problems theoretically, and present a suite of algorithms with provable guarantees. We conduct rigorous large scale experiments involving multiple real world datasets by appropriately adapting multiple state-of-the-art solutions to demonstrate the effectiveness and scalability of our proposed methods. 

Supramolecular nanocages with inner cavities have attracted increasing attention due to their fascinating molecular aesthetics and vast number of potential applications. Even though a wide array of discrete supramolecular cages with precisely designed sizes and shapes have been established, the controlled assembly of higher-order supramolecular frameworks from discrete molecular entities still represents a formidable challenge. In this work, a novel metallo-organic cage [Zn12L4] was assembled based on a triphenylene-cored hexapod terpyridine ligand. Synchotron X-ray analysis revealed a pair of enantiomeric cages in the crystal with flexible ligands twisted clockwise or anticlockwise due to steric hindrance in the structure. Interestingly, due to the strong π–π intermolecular interaction between triphenylene units, a controlled hierarchical packing of sphere-like cages in the crystal was established having a sparse packing mode with huge channels of around 3.6 nm diameter. This research sheds light on the design of strong π–π interactions in supramolecular hierarchical packing and materials science. 

Peer groups leverage the presence of knowledgeable individuals in order to increase the knowledge level of other participants. The `smart' formation of peer groups can thus play a crucial role in educational settings, including online social networks and learning platforms. Indeed, the targeted groups formation problem, where the objective is to maximize a measure of aggregate knowledge, has received considerable attention in recent literature. In this paper we initiate a dynamic variant of the problem that, unlike previous works, allows the change of group composition over time while still targeting to maximize the aggregated knowledge level. The problem is studied in a principled way, using a realistic learning gain function and for two different interaction modes among the group members. On the algorithmic side, we present DyGroups, a generic algorithmic framework that is greedy in nature and highly scalable. We present non-trivial proofs to demonstrate theoretical guarantees for DyGroups in a special case. We also present real peer learning experiments with humans, and perform synthetic data experiments to demonstrate the effectiveness of our proposed solutions by comparing against multiple appropriately selected baseline algorithms. 

Abstract Background The western flower thrips, Frankliniella occidentalis (Pergande), is a globally invasive pest and plant virus vector on a wide array of food, fiber, and ornamental crops. The underlying genetic mechanisms of the processes governing thrips pest and vector biology, feeding behaviors, ecology, and insecticide resistance are largely unknown. To address this gap, we present the F. occidentalis draft genome assembly and official gene set. Results We report on the first genome sequence for any member of the insect order Thysanoptera. Benchmarking Universal Single-Copy Ortholog (BUSCO) assessments of the genome assembly (size = 415.8 Mb, scaffold N50 = 948.9 kb) revealed a relatively complete and well-annotated assembly in comparison to other insect genomes. The genome is unusually GC-rich (50%) compared to other insect genomes to date. The official gene set (OGS v1.0) contains 16,859 genes, of which ~ 10% were manually verified and corrected by our consortium. We focused on manual annotation, phylogenetic, and expression evidence analyses for gene sets centered on primary themes in the life histories and activities of plant-colonizing insects. Highlights include the following: (1) divergent clades and large expansions in genes associated with environmental sensing (chemosensory receptors) and detoxification (CYP4, CYP6, and CCE enzymes) of substances encountered in agricultural environments; (2) a comprehensive set of salivary gland genes supported by enriched expression; (3) apparent absence of members of the IMD innate immune defense pathway; and (4) developmental- and sex-specific expression analyses of genes associated with progression from larvae to adulthood through neometaboly, a distinct form of maturation differing from either incomplete or complete metamorphosis in the Insecta. Conclusions Analysis of the F. occidentalis genome offers insights into the polyphagous behavior of this insect pest that finds, colonizes, and survives on a widely diverse array of plants. The genomic resources presented here enable a more complete analysis of insect evolution and biology, providing a missing taxon for contemporary insect genomics-based analyses. Our study also offers a genomic benchmark for molecular and evolutionary investigations of other Thysanoptera species.