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Relating ample and biample topological categories with Boolean restriction and range semigroups
Get PDFWe extend the equivalence by Cockett and Garner between restriction monoids and ample categories to the setting of Boolean range semigroups which are non-unital one-object versions of range categories. We show that Boolean range semigroups are equivalent to ample topological categories where the range map is open, and étale Boolean range semigroups are equivalent to biample topological categories. These results yield the equivalence between étale Boolean range semigroups and Boolean birestriction semigroups and a characterization of when a Boolean restriction semigroup admits a compatible cosupport operation. We also recover the equivalence between Boolean birestriction semigroups and biample topological categories by Kudryavtseva and Lawson. Our technique builds on the usual constructions relating inverse semigroups with ample topological groupoids via germs and slices
Strokovne podlage za pripravo strategije razvoja za trajnostno slovensko sredozemsko kmetijstvo
Get PDFStrategija razvoja temelji na štirih stebrih: trajnost, poslovno okolje, tehnološki napredek ter znanje in prenos tega. Poseben poudarek je na prilagajanju podnebnim spremembam, zaščiti tal in vodnih virov in spodbujanju lokalne samooskrbe. Zasnovana mreža znanja je ključna za povezovanje raziskovalcev, svetovalcev in kmetov ter omogoča učinkovit prenos znanja, razvoj novih praks in vključevanje mladih strokovnjakov. Njeno delovanje bo pomembno tudi za širjenje pridelave sredozemskih rastlin v druge regije Slovenije
Cryo-EM structures of a protein pore reveal a cluster of cholesterol molecules and diverse roles of membrane lipids
Get PDFThe structure and function of membrane proteins depend on their interactions with lipids that constitute membranes. Actinoporins are α-pore-forming proteins that bind preferentially to sphingomyelin-containing membranes, where they oligomerize and form transmembrane pores. Through a comprehensive cryo-electron microscopic analysis of a pore formed by an actinoporin Fav from the coral Orbicella faveolata, we show that the octameric pore interacts with 112 lipids in the upper leaflet of the membrane, reveal the roles of lipids, and demonstrate that the actinoporin surface is suited for binding multiple receptor sphingomyelin molecules. When cholesterol is present in the membrane, it forms a cluster of four molecules associated with each protomer. Atomistic simulations support the structural data and reveal additional effects of the pore on the lipid membrane. These data reveal a complex network of protein-lipid and lipid-lipid interactions and an underrated role of lipids in the structure and function of transmembrane protein complexes
A simple multiple flow regime modeling approach of induced flow in external loop airlift reactors
Get PDFAccurate treatment of heat and mass transfer processes inside airlift reactors requires accurate velocity field information. This study presents a novel one-dimensional model forecasting induced liquid flow within an external loop airlift reactor across diverse flow regimes. The approach is grounded on homogeneous flow assumption, augmented by a novel correction term derived through modeling of turbulence-induced pressure losses behind gas structures, employing the separated flow model (Lockhart-Martinelli). The model was assessed by comparing the results with purpose-provided experimental data utilizing air and demineralized water. The gas and liquid superficial velocities ranged from 0.001-0.6 m/s and 0.2–1.1 m/s, respectively. Within ± 10 %, an agreement between the novel model and experimental data was observed for both bubbly, separated, and in- termediate flow regimes. A similarly robust agreement was confirmed through comparisons with five published experimental datasets. The distinctive feature of this model is its ability to accommodate multiple flow regimes in a unified manner. It circumvents the necessity for specific regime modeling by introducing a correction term with a complexity marginally surpassing that of the conventional homogeneous flow approach. Beyond its primary application in airlift reactors, the model provides a unified framework for modeling two-phase flow hydrody- namics in thermal applications, particularly in flow boiling and bubble-induced convective heat transfer systems. The model’s simple yet effective structure also allows for integration into higher-fidelity heat transfer simula- tions, making it valuable for boiling heat transfer studies, enhanced cooling strategies, and industrial multiphase flow applications
