1,322 research outputs found
A Minimal Poset Resolution of Stable Ideals
We use the theory of poset resolutions to construct the minimal free
resolution of an arbitrary stable monomial ideal in the polynomial ring whose
coefficients are from a field. This resolution is recovered by utilizing a
poset of Eliahou-Kervaire admissible symbols associated to a stable ideal. The
structure of the poset under consideration is quite rich and in related
analysis, we exhibit a regular CW complex which supports a minimal cellular
resolution of a stable monomial ideal.Comment: 25 pages, 2 figure
The Betti poset in monomial resolutions
Let be a finite partially ordered set with unique minimal element
. We study the Betti poset of , created by deleting elements for which the open interval is acyclic. Using basic
simplicial topology, we demonstrate an isomorphism in homology between open
intervals of the form and corresponding open intervals
in the Betti poset. Our motivating application is that the Betti poset of a
monomial ideal's lcm-lattice encodes both its -graded Betti
numbers and the structure of its minimal free resolution. In the case of rigid
monomial ideals, we use the data of the Betti poset to explicitly construct the
minimal free resolution. Subsequently, we introduce the notion of rigid
deformation, a generalization of Bayer, Peeva, and Sturmfels' generic
deformation
Industrial Aquaculture: History, Problems, Potential - Political Economic Review and Analysis of Socioecological Issues in Global Industrial Aquaculture Supply Chains
*This report highlights characteristics of global industrial aquaculture value chains. For example: Most producers are located in global South countries, but rely on input (e.g. feed, pest control agents) that are often in the hands of wealthy corporations in the EU and U.S. Global supply chains are buyer-driven, with massive grocery and retail food conglomerates based in the global North being the most powerful buyers. *Several key concerns related to feed are emphasized. For example: Social concerns of worker exploitation and forced labor to capture wild fish to feed farmed fish. Marine ecological concerns as wild fish stock suffers as a result of pressures to obtain "trash fish" as aquafeed. Concerns with impacts on terrestrial environment such as cutting down forests to cultivate soybean to feed farmed fish.*The prevalence of pests and diseases and the heavy use of antibiotics in industrial aquaculture operations is another concern. Intensive aquaculture also raises ethical concerns with regard to the welfare of the farmed aquatic animals.*The "displacement paradox" and the "Jevons paradox" in industrial aquaculture is explained.*The report cautions against the use of regulations that emphasize market mechanisms and new technologies as key solutions to industrial aquaculture with global value chains. It recommends instead the promotion of small-scale local supply chains, the production of species that are less reliant on intensive inputs, more in-tune with their ecological surroundings, and lower on the food chain (e.g. mussels, oysters)
Comparative profiling of the transcriptional response to infection in two species of Drosophila by short-read cDNA sequencing
<p>Abstract</p> <p>Background</p> <p>Homology-based comparisons of the genes involved in innate immunity across many insect taxa with fully sequenced genomes has revealed a striking pattern of gene gain and loss, particularly among genes that encode proteins involved in clearing pathogens (effectors). However, limited functional annotation in non-model systems has hindered understanding of evolutionary novelties in the insect innate immune system.</p> <p>Results</p> <p>We use short read sequencing technology (Illumina/Solexa) to compare the transcriptional response to infection between the well studied model system <it>Drosophila melanogaster </it>and the distantly related drosophilid <it>D. virilis</it>. We first demonstrate that Illumina/Solexa sequencing of cDNA from infected and uninfected <it>D. melanogaster </it>recapitulates previously published microarray studies of the transcriptional response to infection in this species, validating our approach. We then show that patterns of transcription of homologous genes differ considerably between <it>D. melanogaster </it>and <it>D. virilis</it>, and identify potential candidates for novel components of the <it>D. virilis </it>immune system based on transcriptional data. Finally, we use a proteomic approach to characterize the protein constituents of the <it>D. virilis </it>hemolymph and validate our transcriptional data.</p> <p>Conclusion</p> <p>These results suggest that the acquisition of novel components of the immune system, and particularly novel effector proteins, may be a common evolutionary phenomenon.</p
The Technology Bias in Entrepreneur-Investor Negotiations
Entrepreneur-investor negotiations are pivotal for ventures in need of funding. Yet, to date, little is known about the dynamics of these negotiations. We investigate a critical feature of this phenomenon by examining the role of technology, via cognitive heuristics, in shaping entrepreneur and investor perceptions as well as subsequent negotiation outcomes. In a controlled laboratory setting, we simulated 103 negotiations between entrepreneurs and investors. We hypothesize and find that there is a pervasive technology bias that influences the perceptions of both parties of the negotiation, and consequently negotiation outcomes. Our findings offer unique insights into the relationships of technology, cognitive heuristics, and negotiations. We discuss the implications for both practitioners and theoreticians in the areas of technology, decision making, negotiations, and entrepreneurial financing
Copper-catalyzed enantioselective synthesis of β-Boron β-Amino Esters
In this report, the enantioselective, copper-catalyzed borylation of β-amidoacrylates is disclosed. A broad variety of biologically important α-aminoboronates has been prepared with consistently high levels of enantiocontrol using an inexpensive copper catalyst and a commercially available chiral ligand. The method can be applied to the synthesis of novel boron-containing dipeptides and hemiboronatesWe thank the European Research Council (ERC-337776),
MINECO (CTQ2016-78779-R), National Science Foundation
(1151092 and 1543699) for financial support. M. T. thanks
MICINN for RyC contrac
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