Generation of plasmon-polaritons in epsilon-near-zero polaritonic metamaterial

In this paper, we study the generation of plasmon-polaritons in the epsilon-near-zero nanorod polaritonic metamaterial by using nonlocal effective medium approximation (EMT). The results indicate that the nonlocal EMT is the simplest and most accurate approach to describe the characteristics of plasmon-polaritons at the epsilon-near-zero regime (e ≈ 0) in the polaritonic metamaterial. In contrast, the Maxwell-Garnett effective medium approximation is considered to be the most general method to study the generated plasmon-polaritons in metamaterials. An additional plasmon-polariton is found in the polaritonic metamaterial through the nonlocal EMT, which could not be found with the Maxwell-Garnett EMT. A flat longitudinal wave-number of the excited plasmon-polariton occurs in the angle of incident light ranging from –20 to 20°, leading to the collinear group-velocity vectors, and its energy will be carried in one direction. The findings can be used in some applications in optical communication

Factores que afectan el ciclo de vida del producto en las empresas electrónicas: evidencia de un país emergente

Introduction:This paper is the product of the study “Factors affecting product life cycle in electronic enterprises – Evidence from an emerging country” developed at the Electric Power University and National Economics University between 2020 and 2022. Problem:The electronic manufacturing industry is increasingly developing in emerging markets and integrating into the global economy. The life cycle of electronic products is shorter and requires management.Objective:The paper aims to study factors that affect the product life cycle in Vietnamese electronic enterprises. The study helps managers in cost management. Methodology:The paper used a survey of non-probability sampling, and applied regression analysis to examine Vietnamese electronic enterprises. The analysis is done by SPSS and Smart PLS software. Results:The research results indicate that technology, consumer trends, and R&D are factors affecting product life cycle and post-sale service, and disposal has no impact on electronic products’ life cycle. This could be explained by the fact that electronic products are constantly updating and their life cycle is short, that post-sales service does not play a key role, and that waste treatment after sales is not taken seriously by manufacturers, customers, or other related parties. Conclusion:The results give some meaningful insights for electronics or other enterprises in Vietnam to use effective management of product life cycle. Originality:The results of this paper provide practical insights into the management of product life cycle and cost management of product life cycle for researchers and managers.Limitations:The research model should be expanded and the sample size increased to get an overview and greater insight.Introducción: Este artículo es producto del estudio “Factores que afectan el ciclo de vida del producto en empresas electrónicas – Evidencia de un país emergente” desarrollado en la Electric Power University y la National Economics University entre 2020 y 2022.Problema: La industria de fabricación electrónica se está desarrollando cada vez más en los mercados emer-gentes y se está integrando a la economía global. El ciclo de vida de los productos electrónicos es más corto y requiere gestión. Objetivo: El documento tiene como objetivo estudiar los factores que afectan el ciclo de vida del producto en las empresas electrónicas vietnamitas. El estudio ayuda a los gerentes en la gestión de costos. Metodología: El documento utilizó una encuesta de muestreo no probabilístico y aplicó un análisis de regresión para examinar las empresas electrónicas vietnamitas. El análisis se realiza mediante el software SPSS y Smart PLS. Resultados: Los resultados de la investigación indican que la tecnología, las tendencias de consumo y la I+D son factores que afectan el ciclo de vida del producto y el servicio postventa, y que el desecho no tiene impacto en el ciclo de vida de los productos electrónicos. Esto podría explicarse por el hecho de que los productos electrónicos se actualizan constantemente y su ciclo de vida es corto, que el servicio posventa no juega un papel clave y que el tratamiento de residuos posventa no es tomado en serio por los fabricantes, clientes u otras partes relacionadas. Conclusión: Los resultados brindan algunas ideas significativas para la electrónica u otras empresas en Vietnam para utilizar una gestión eficaz del ciclo de vida del producto. Originalidad: los resultados de este documento brindan información práctica sobre la gestión del ciclo de vida del producto y la gestión de costos del ciclo de vida del producto para investigadores y gerentes.Limitaciones: el modelo de investigación debe ampliarse y aumentar el tamaño de la muestra para obtener una visión general y una mayor comprensión

Norepinephrine and dopamine increase motility, biofilm formation and virulence of Vibrio harveyi

Vibrio harveyi is one of the major pathogens of aquatic organisms, affecting both vertebrates and invertebrates, and causes important losses in the aquaculture industry. In order to develop novel methods to control disease caused by this pathogen, we need to obtain a better understanding of pathogenicity mechanisms. Sensing of catecholamines increases both growth and production of virulence-related factors in pathogens of terrestrial animals and humans. However, at this moment, knowledge on the impact of catecholamines on the virulence of pathogens of aquatic organisms is lacking. In the present study, we report that in V harveyi, norepinephrine (NE) and dopamine (Dopa) increased growth in serum-supplemented medium, siderophore production, swimming motility, and expression of genes involved in flagellar motility, biofilm formation, and exopolysaccharide production. Consistent with this, pretreatment of V harveyi with catecholamines prior to inoculation into the rearing water resulted in significantly decreased survival of gnotobiotic brine shrimp larvae, when compared to larvae challenged with untreated V harveyi. Further, NE-induced effects could be neutralized by alpha-adrenergic antagonists or by the bacterial catecholamine receptor antagonist LED209, but not by beta-adrenergic or dopaminergic antagonists. Dopa-induced effects could be neutralized by dopaminergic antagonists or LED209, but not by adrenergic antagonists. Together, our results indicate that catecholamine sensing increases the success of transmission of V harveyi and that interfering with catecholamine sensing might be an interesting strategy to control vibriosis in aquaculture. We hypothesize that upon tissue and/or hemocyte damage during infection, pathogens come into contact with elevated catecholamine levels, and that this stimulates the expression of virulence factors that are required to colonize a new host

The basic chemical parameters of berries from some gooseberry cultivars

Tato bakalářská práce se zabývá stanovením základních chemických parametrů v plodech drobného bobulovitého ovoce, angreštu srstky (Grossularia uva-crispa). V teoretické části je uvedeno taxonomické zařazení angreštu srstky a jeho botanická charakteristika. Je popsána také historie pěstování a šlechtění, vhodné podmínky, včetně nejčastějších chorob a pomologie jednotlivých odrůd. Další kapitola je věnována chemickému složení plodů angreštu srstky. V experimentální části byla provedena stanovení vybraných chemických parametrů (výtěžnost šťávy, obsah rozpustné sušiny, obsah celkové sušiny, pH, titrační kyselost, formolové číslo a obsah redukujících cukrů) v plodech několika odrůd angreštu.This bachelor thesis deals with assessment of basic chemical parameters in berries of some gooseberry cultivars. In theoretical part the taxanomy classification of gooseberry and its botanical characteristics are mentioned. The history of breeding, appropriate conditions, including the most common diseases and pomology of each cultivars are also described. Next chapter is dedicated to the chemical composition of gooseberry. In experimental part some chosen chemical parameters (yield of juice, soluble dry matter content, dry matter general content, pH, titratable acidity, formol number and reducing saccharides content) of few gooseberry cultivars were determined.

Temporal patterns of synchrony in a pyramidal-interneuron gamma (PING) network

Synchronization in neural system plays an important role in many brain functions. Synchronization in the gamma frequency band (30Hz-100Hz) is involved in a variety of cognitive phenomena; abnormalities of the gamma synchronization are found in schizophrenia and autism spectrum disorder. Frequently, the strength of synchronization is not very high and is intermittent even on short time scales (a few cycles of oscillations). That is, the network exhibits intervals of synchronization followed by intervals of desynchronization. Neural circuits dynamics may show different distributions of desynchronization durations even if the synchronization strength is fixed. In this study, we use a conductance-based neural network exhibiting pyramidal-interneuron (PING) gamma rhythm to study the temporal patterning of synchronized neural oscillations. We found that changes in the synaptic strength (as well as changes in the membrane kinetics) can alter the temporal patterning of synchrony. Moreover, we found that the changes in the temporal pattern of synchrony may be independent of the changes in the average synchrony strength. Even though the temporal patterning may vary, there is a tendency for dynamics with short (although potentially numerous) desynchronizations, similar to what was observed in experimental studies of neural activity synchronization in the brain. Recent studies suggested that the short desynchronizations dynamics may facilitate the formation and the break-up of transient neural assemblies. Thus, the results of this study suggest that changes of synaptic strength may alter the temporal patterning of the gamma synchronization as to make the neural networks more efficient in the formation of neural assemblies and the facilitation of cognitive phenomena

INSTITUTIONAL OWNERSHIP AND CAPITAL STRUCTURE: A CASE OF UK FIRMS

This study investigates the influence of institutional ownership on the target leverage and the capital structure adjustment speeds of UK firms under the framework of dynamic trade-off theory. I draw the financial data from 294 non-financial and -utility firms of FTSE All Shares Index over 2010-2019 period. To overcome endogenous problems arising from the dynamic nature and the simultaneous relationships between capital structure and other firm-specific characteristics, the main approach in this dissertation is Generalized Method of Moments. The empirical models reveal that institutional ownership is an important determinant of the desired book debt ratios in UK firms. Meanwhile, I find no evidence that institutional ownership affects the market debt ratios in these firms. The removal of institutional holdings from the initial regressions suggests that this variable should only serve as instrumental variables for the endogenous variables in the market debt ratios’ model rather than a regressor like the book-based one. At the same time, the partial adjustment models show that UK firms rapidly diminish 39.3% of the gap between the actual book debt ratios and the target levels each year, while the number for the market-based indicator is significant lower at 22.9%. Consistent with the regressions of fixed-effects models, the dynamic models expose that profitability negatively correlates with both book- and market-based indicators, whereas size positively relates to the book one only. By assuming capital structure adjustment speeds are a function of institutional holdings, I document that there is no correlation between these two factors

The Impact of Foreign Direct Investment on Economic Growth: Evidence from Vietnam

The relationship between Foreign Direct Investment (FDI) and economic growth has long been a topic of great interest in the field of international development. Although this interest has provided rich insights into the impact of FDI on growth in developing countries, there are very few empirical analyses of the linkage in Vietnam compared to other developing countries. Therefore, this study investigates the impact of FDI inflows on economic growth in Vietnam over the period from 1990 to 2013 using time series analysis techniques that address the problem of nonstationarity. Specifically, the Unit root test and Cointegration approach are applied to ensure that the regressions are not spurious. The empirical results reveal that FDI inflows, domestic investment, trade openness and secondary education have positive impacts on economic growth whereas inflation rate is found to have negative effect on economic growth. In addition, the impact of government consumption on economic growth is negative and statistically insignificant. Ultimately, this paper suggests that Vietnamese government should improve regulations governing business activities by easing the process of business start-up, controlling price, enhancing public spending on education and training, and augmenting cooperation between training centers and Foreign-invested enterprises. Keywords: Foreign Direct Investment, economic growth, time series, unit root test, cointegration, Vietnam