The Hardy-Littlewood Maximal Operator on Discrete Weighted Morrey Spaces

In this paper, we introduce a discrete version of weighted Morrey spaces, and discuss the inclusion relations of these spaces. In addition, we obtain the boundedness of discrete weighted Hardy-Littlewood maximal operators on discrete weighted Lebesgue spaces by establishing a discrete Calder\'on-Zygmund decomposition for weighted $l^1$-sequences. Furthermore, the boundedness of discrete Hardy-Littlewood maximal operators on discrete weighted Morrey spaces is established

THREE ESSAYS ON THE EFFECTS AND THE STRATEGY OF TECHNOLOGY IMPROVEMENTS IN THE INTERNATIONAL TRADE FRAMEWORK

The main purpose of this study is to investigate the optimal strategy and the welfare effects of technology improvements in the open economy. The first essay, "Hicks Theorem: Effects of Technological Improvement in the Ricardian Model" studies these questions with the Ricardian model. The essay formally proves Hicks' (1953) insight into the effects of technological improvement: uniform technological improvement at home benefits all countries (or at least does not hurt); export-biased technological improvement at home benefits the foreign country (or at least does not hurt), but import-biased technological improvement at home can hurt the foreign country if the comparative advantage is not reversed.The paper then studies optimal strategies of technological improvement and shows that for a small country it is optimal to choose export-biased technological improvement. For a large country, it is optimal to improve technology in both sectors at a rate proportional to the consumers' expenditure share.The second essay, "A Two-Sector Eaton and Kortum Model: Technological Changes and International Trade" studies the effects of technological changes with a two-sector Eaton and Kortum model. This paper distinguishes two types of technology changes: changes in the technology levels (technology improvements) and changes in the dispersion of productivity of firms. The paper shows that technology improvements always increase the total trade. Technology improvements increase inter-industry trade if they originate in the comparative advantage sector, otherwise they decrease inter-industry trade. Increases in the degree of heterogeneity always increase the total trade and inter-industry trade.The essay also analyzes the welfare effects of technology improvements and yields some new results. It shows that with the Cobb-Douglas utility function technology improvements are always beneficial to the innovator. In agreement with the literature, export-biased improvements benefit the foreign country. In a departure from the literature, however, the paper shows that import-biased improvements could benefit the foreign country. The essay also shows that when the final goods are complements, immiserizing growth may occur.The theoretical model of the paper shows that the net exports of the comparative advantage sector are positive while those of the other sector are negative. This offers us a testable hypothesis about the Ricardian trade model. Using the OECD STAN databases, the paper conducts some simple tests concerning the prediction and finds strong support for it. The Ricardian model is one of the pillars of the international trade theory, but there have been few empirical tests of it. The results of this work will enrich the literature in this field.The third essay, "Hicks Path: The Optimal Strategy of Technological Improvement in the open economy" extends the Eaton and Kortum framework into a multi-sector model to analyze the innovation pattern of countries. The model shows that the R&D activities are determined by sectoral expenditure and research efficiency. The model also shows that the laissez faire R&D input level is less than the socially optimal R&D input level in autarky when there are two sectors. In the open economy the R&D input in an industry depends on the country's advantage in the industry.Using the OECD STAN database, the empirical analysis finds some support for Hicks' path, a technology improvement strategy for countries advanced by Hicks, but it also indicates that the R&D pattern in the real world might be richer than what Hicks predicted

Catching butterflies in the sky: Extended catalog of winged or X-shaped radio sources from the latest FIRST data release

We present a catalog of 290 "winged" or X-shaped radio galaxies (XRGs) extracted from the latest (2014 December 17) data release of the "Very Large Array Faint Images of the Radio Sky at Twenty centimeter." We have combined these radio images with their counterparts in the TIFR GMRT sky survey at 150 MHz, in an attempt to identify any low surface brightness radio emission present in these sources. This has enabled us to assemble a sample of 106 "strong" XRG candidates and 184 "probable" XRG candidates whose XRG designation needs to be verified by further observations. The present sample of 290 XRG candidates is almost twice as large as the number of XRGs currently known. Twenty-five of our 290 XRG candidates (9 "strong" and 16 "probable") are identified as quasars. Double-peaked narrow emission lines are seen in the optical spectra of three of the XRG candidates (two "strong" and one "probable"). Nearly 90% of the sample is located in the FR II domain of the Owen-Ledlow diagram. A few of the strong XRG candidates have a rather flat radio spectrum (spectral index alpha flatter than -0.3) between 150 MHz and 1.4 GHz, or between 1.4 and 5 GHz. Since this is not expected for lobe-dominated extragalactic radio sources (like nearly all known XRGs), these sources are particularly suited for follow-up radio imaging and near-simultaneous measurement of the radio spectrum.Comment: 22 pages, 9 figures, 3 tables, accepted for publication in ApJ

Short video marketing : what, when and how short-branded videos facilitate consumer engagement

Purpose This study explores whether and how four main factors of short-branded video content (content matching, information relevance, storytelling and emotionality) facilitate consumer engagement (likes, comments and shares), as well as the moderating effect of the release time (morning, afternoon and evening) in such relationships. Design/methodology/approach This study uses Python to write programs to crawl relevant data information, such as consumer engagement and short video release time. It combines coding methods to empirically analyze the impact of short-branded video content characteristics on consumer engagement. A total of 10,240 Weibo short videos (total duration: 238.645 h) from 122 well-known brands are utilized as research objects. Findings Empirical results show that the content characteristics of short videos significantly affected consumer engagement. Furthermore, the release time of videos significantly moderated the relationship between the emotionality of short videos and consumer engagement. Content released in the morning enhanced the positive impact of warmth, excitement and joy on consumer engagement, compared to that released in the afternoon. Practical implications The findings provide new insights for the dissemination of products and brand culture through short videos. The authors suggest that enterprises that use brand videos consider content matching, information relevance, storytelling and emotionality in their design. Originality/value From a broader perspective, this study constructs a new method for comprehensively evaluating short-branded video content, based on four dimensions (content matching, information relevance, storytelling and emotionality) and explores the value of these dimensions for creating social media marketing success, such as via consumer engagement.© 2023 Emerald Publishing Limited. This manuscript version is made available under the Creative Commons Attribution–NonCommercial 4.0 International (CC BY–NC 4.0) license, https://creativecommons.org/licenses/by-nc/4.0/fi=vertaisarvioitu|en=peerReviewed

Enzymatic Transesterification of Ethyl Ferulate with Fish Oil and Reaction Optimization by Response Surface Methodology

Ispitana je enzimska transesterifikacija ulja dobivenog iz jetre bakalara etil ferulatom (EF), primjenom katalizatora Novozym® 435. Svrha je rada bila istražiti mogućnost primjene ove sinteze u industrijskoj proizvodnji feruloil ribljeg ulja. Produkti reakcije karakterizirani su modificiranom HPLC-ESI-TOF-MS metodom. Ispitan je utjecaj dodatka glicerola na sastav nastalih feruloil acilglicerola. Biokonverzija EF bila je kudikamo veća u prisutnosti glicerola, a osobito s povećanjem udjela nastalog feruloil ribljeg ulja. Stoga je radi optimiranja reakcije u sustav dodana ekvimolarna količina glicerola. Ispitan je zajednički utjecaj temperature (od 40 do 70 °C), vremena reakcije (1-5 dana), udjela enzima (2-20 %) i molarnog omjera ribljeg ulja i EF (1-5). Primjenom metode odzivnih površina određeni su najpogodniji parametri za maksimalni prinos feruolil ribljeg ulja, i to: temperatura od 70 °C, udjel enzima od 4,3 %, molarni omjer supstrata od 4,7 i vrijeme reakcije od 5 dana. Pri tim je uvjetima postignut udjel EF od 92,4 %, feruloil ribljeg ulja od 80,4 %, a smanjen udjel nusprodukata na samo 11,4 %.The enzymatic transesterification of ethyl ferulate (EF) with fish oil from cod liver was investigated with Novozym® 435 as catalyst under solvent-free conditions. The purpose of the study is to evaluate the synthesis system for the production of feruloyl fish oil in industry. The modified HPLC method was first set up to characterise the reaction products together with liquid chromatography electrospray time-of-flight mass spectrometry (HPLC-ESI-TOF-MS). The influence of the addition of glycerol to the system on the feruloyl acylglycerol profile was investigated in terms of transesterification performance. The bioconversion rate of EF can be significantly increased with the increased formation of feruloyl fish oil products when appropriate amount of glycerol is present in the reaction. Therefore, an equivalent molar amount of glycerol was added to EF for the practical optimization of the system. The mutual effects of temperature (40 to 70 °C), reaction time (1 to 5 days), enzyme load (2 to 20 %) and molar ratio of fish oil and EF in the substrate (1 to 5) were thus studied with the assistance of response surface methodology (RSM) for the purpose of maximizing the formation of feruloyl fish oil. The models were well fitted and verified. The optimized conditions were found to be: temperature 70 °C, enzyme load 4.3 %, substrate ratio 4.7, and reaction time 5 days. Under these conditions, the maximum conversion of EF reached 92.4 %, and the formation of feruloyl fish oil reached 80.4 %, but the formation of by-product was minimized to 11.4 % only

Optimization Analysis of Permanent-Magnet Direct-Drive Wind Turbine Elbow Shape Nacelle

[Introduction] In view of the irregular geometric shape, complex load and heavy weight of the nacelle of a permanent magnet direct drive wind turbine, it is necessary to optimize the analysis and design. [Method] Based on the finite element analysis of the geometric parameters of the nacelle and the calculation results of the shape of the elbow, the finite element analysis was established. [Result] After optimization, the maximum von Mises stress of the nacelle is reduced from 181 MPa to 173 MPa, and the stress is reduced by 4.4%, which meets the strength requirements. The weight of the nacelle is reduced by 14.2% from 52.7 tons to 45.2 tons. [Conclusion] The research shows that the optimization effect is obvious, which provides a reference for the design and optimization method of such nacelle of wind turbine

Edge-Mediated Skyrmion Chain and Its Collective Dynamics in a Confined Geometry

The emergence of a topologically nontrivial vortex-like magnetic structure, the magnetic skyrmion, has launched new concepts for memory devices. There, extensive studies have theoretically demonstrated the ability to encode information bits by using a chain of skyrmions in one-dimensional nanostripes. Here, we report the first experimental observation of the skyrmion chain in FeGe nanostripes by using high resolution Lorentz transmission electron microscopy. Under an applied field normal to the nanostripes plane, we observe that the helical ground states with distorted edge spins would evolves into individual skyrmions, which assemble in the form of chain at low field and move collectively into the center of nanostripes at elevated field. Such skyrmion chain survives even as the width of nanostripe is much larger than the single skyrmion size. These discovery demonstrates new way of skyrmion formation through the edge effect, and might, in the long term, shed light on the applications.Comment: 7 pages, 3 figure