These notes deal with some recent assertions about truncations $f \mapsto |f|$ and compositions $f \mapsto g\circ f$ in the spaces $A^s_{p,q}(\mathbb{R}^n)$, $A \in \{B,F \}$.
Mixed fisheries refer to fishing activities that catch more than one species simultaneously, and a species may be fished using different gear. A trawl fishery shares these features to exploit multiple species simultaneously, with diverse fishing gear and strategies. The situation becomes more complex when interactions among fleet dynamics, fishing activities, and fishery resources are involved and influence each other. Information regarding the operational patterns may be hidden in a set of long-term big data. This study aims to investigate the fishery structure and fleet dynamics of trawl fisheries in Taiwan for spatial planning and management, based on a long-term dataset from a management system that collects information by using voyage data recorders (VDR) and dockside observers. We applied a two-step data mining process with a clustering algorithm to classify the main groups of fishery resources and then identified 18 catch métiers based on catch composition. The target species, operation pattern, and fishing season were determined for each métier, and associated with the relevant fishery resources and the fishing gear used. Additionally, fishing effects on target species were estimated using information on fishing grounds and trajectories from VDR. The métier-based approach was successfully applied to define the six major fishery resources targeted by trawlers. We examined the key features of fishing activity associated with catch composition and spatial-temporal fishing metrics, which could be used to provide suggestions for the spatial planning and management of the mixed trawl fishery in the offshore waters of Taiwan.
We introduce a set of operator-valued invariants for localization of operator tuples in the Cowen-Douglas class, with which a Specht-type criterion for unitary equivalence is obtained.
Let $(C(t))\in\mathbb{R}}$ be a cosine function in a unital Banach algebra. We give a simple proof of the fact that if lim sup$\_{t\to 0}\vert C(t)-1\_A\vert\textless{}2,$ then $lim sup\_{t\to 0}\Vert C(t)-1\_A\Vert=0.$
A series of porous poly(styrene-divinylbenzene) monoliths (polyHIPE) was synthesized by high internal phase emulsions (HIPE). The effects of the ethanol contents on the microstructure of the polyHIPE were characterized by scanning electron microscopy and mercury intrusion porosimeter. The adsorption and release behaviors of the polyHIPE for a monomer mixture consisting of dicyclopentadiene (DCPD) /styrene (St) (DS, mass ratio of 9/1) were investigated. The polymerization of the mixture DS within pores of the polyHIPE was studied. The results showed that the microstructure of the polyHIPE was significantly influenced by the ethanol content. The increase of ethanol in the HIPE increased the internal pore diameter and decreased the pore volume of the polyHIPE, thus decreased the DS absorption and increased the release rate. The DS monomer can enter the pores(cavities, windows) and fill the original holes after the polymerization. Compared with conventional polymerization of DCPD/St, the poly(DCPD/St) (pDS) obtained from confined spaces possess higher molecular weight, broader molecular weight distribution, and higher Tg. As the pore diameter increased, the effect of space confinement reduced, and the performances of pDS were closed to that prepared by conventional polymerization.
In this note unbounded hyperexpansive weighted composition operators are investigated. AS a consequence unbounded hyperexpansive multiplication and composition operators are characterized.