This article focuses on reducing mutual coupling between the ports of dielectric resonator antenna (DRA) using defected ground structures (DGSs). The antenna has the dimension of 50 mm × 50 mm × 8.5 mm. The resonating element in the proposed two-port radiator consists of a cylindrical structure of alumina ceramic (ɛr = 9.8). The rectangular-shaped aperture is utilized to excite both of the resonating elements. The resonating ceramic elements acting as radiators are offset-fed to enhance the antenna’s coupling. Combining interdigital-shaped and semicircular arc-shaped DGSs improves isolation between two resonating elements, embodying the structural novelty. The measured operating frequency range of Port-1 and Port-2 is 5.19–6.7 and 5.15–6.68 GHz, resonating at 5.58 and 5.56 GHz, respectively. The measured mutual coupling between the two ports is −35.5 dB. The measured gain for Port-1 is depicted to be 5.5 dB. The presented multiple-input–multiple-output (MIMO) radiator in this article is an appropriate candidate for WLAN (5.25–5.35, 5.47–5.725, 5.725–5.85, 5.850–5.925 GHz) and WiMAX(5.5 GHz) applications. All the simulated and experimentally observed MIMO parameters of the radiator are discovered to be within optimal bounds.

We prove several results concerning the existence of surfaces of section for the geodesic flows of closed orientable Riemannian surfaces. The surfaces of section $\Sigma $ that we construct are either Birkhoff sections, which means that they intersect every sufficiently long orbit segment of the geodesic flow, or at least they have some hyperbolic components in $\partial \Sigma $ as limit sets of the orbits of the geodesic flow that do not return to $\Sigma $. In order to prove these theorems, we provide a study of configurations of simple closed geodesics of closed orientable Riemannian surfaces, which may have independent interest. Our arguments are based on the curve shortening flow.

The world is currently undergoing a technological transformation with numerous innovative concepts emerging. This shift is driven by remarkable advancements in artificial intelligence and the urgent need for decarbonisation. With this comes a growing demand for skilled engineers who can actively contribute at any stage within the life cycle of a product. This can be the generation of new concepts at low Technology Readiness Levels or contributing actively to their development and operational safety. This paper explores the integration of a 1-day practical activity to reinforce theoretical concepts learned within a classroom-based environment. Small groups of students were given the opportunity of engaging with a small helicopter engine (Rolls-Royce Gnome engine) through the disassembly and reassembly of the exhaust and power turbine section while following the manufacturer’s manual and ensuring industrial norms for safe practice. This hands-on activity included an introduction to tooling, a Gnome familiarisation activity, and an introduction to inspection techniques. Based on the feedback recorded, the students experienced a notable improvement in their basic understanding by effectively reinforcing knowledge acquired within the classroom through active engagement with an actual gas turbine engine.

Complicated option pricing models attract much attention in financial industries, as they produce relatively better accurate values by taking into account more realistic assumptions such as market liquidity, uncertain volatility and so forth. We propose a new hybrid method to accurately explore the behaviour of the nonlinear pricing model in illiquid markets, which is important in financial risk management. Our method is based on the Newton iteration technique and the Fréchet derivative to linearize the model. The linearized equation is then discretized by a differential quadrature method in space and a quadratic trapezoid rule in time. It is observed through computations that the accurate solutions for the model emerge using very few grid points and time elements, compared with the finite difference method in the literature. Furthermore, this method also helps to avoid consideration of the convergence issues of the Newton approach applied to the nonlinear algebraic system containing many unknowns at each time step if an implicit method is used in time discretization. It is important to note that the Fréchet derivative supports to enhance the convergence order of the proposed iterative scheme.

The taxonomy of the subfamily Scolytinae has traditionally been based on external morphological attributes corresponding to the elytral declivity, head, and pronotum. Some traits from the general morphology of the aedeagus and spermatheca have been proposed in scarce genera. In this study, we explore and improve a technique of endophallus inflation to apply it in Scolytinae members and to describe its morphology for the first time in 16 species from Dendroctonus Erichson, Ips DeGeer, and Phloeosinus Chapuis. These taxa display differences in the attachment types of endophallus and two distinct inflation and retraction mechanisms. Our results support the use of the internal sac as a taxonomic feature in Scolytinae because each tribe, genus, and species display a particular morphological pattern. The results also indicate use of the internal sac for Dendroctonus taxonomy supports phylogenetic inferences.

This paper proposes an innovative hybrid package integration strategy compatible with silicon-based technologies. It is evaluated beyond 200 GHz by the integration of a WR3 back-to-back waveguide-to-suspended stripline transition designed in BiCMOS technology, relying on metallic split-block package and organic laminate substrate. Simulated insertion loss below 3 dB is observed in the 220–320 GHz frequency band, competing with reported traditional solutions using III–V substrates. The achieved performances lead to promising perspectives for low-cost silicon packaging solutions beyond 200 GHz.

The change in brand from British Railways to British Rail (BR) marked an important moment in the history of Britain’s railway. Running alongside BR’s modernization was a wider process of “professionalization” within the field of marketing. This paper explores how the wider professionalization of marketing impacted BR’s own marketing practices, showing that after 1965 BR opened its doors to new methods, means, and perhaps most importantly, specialists from outside the railway industry. Such marketing efforts helped to frame the railway in terms of individual travelers’ specific economic needs: by 1968 it had effectively segmented its passengers into demographic audiences, and by 1975, BR had a much better understanding of its markets. These individual economies were often highly gendered and saw only mixed success, but ultimately demonstrated an application of research, advertising, and promotion.

We prove that the Center Conjecture passes to the Artin groups whose defining graphs are cones, if the conjecture holds for the Artin group defined on the set of the cone points. In particular, it holds for every Artin group whose defining graph has exactly one cone point.

While much of the scholarship on gender and corruption suggests that women in political office are, or are perceived to be, less corrupt than men, in just the past few years corruption accusations against Brazil's Dilma Rousseff and South Korea's Park Geun-hye have made headlines and led to their impeachment. In this article, we argue women heads of government are actually more likely to be charged with corruption due to pervasive beliefs that women, by their very presence, corrupt public office. Using cross-national data, we first demonstrate that women executives are significantly more likely to be formally accused of corruption than their male counterparts. We then present case studies of Brazilian President Rousseff and Turkish Prime Minister Çiller to demonstrate the powerful role of gendered discourse in motivating suspicion and inflaming elite and public sentiment and thereby driving corruption charges. These findings make a substantial contribution to the literature on gender, leadership and the politics of corruption.

Temperature increase may cause some regions in the world to become marginal or unsuitable for Arabica coffee cultivation, due to either heat and/or marked water deficit. The feasibility of sustainable coffee production in these regions promotes good opportunity of income and value addition for rural producers within an expanding market. This study aimed to identify short-stature Arabica coffee cultivars with the best agronomic and qualitative performance in a low-altitude region. The experiment was located in northeastern São Paulo state, Brazil, at 565 m above sea level. During the experimental period (2014–2018) the average annual and November temperatures were 23.0 and 24.3°C, respectively, with an average annual water deficit of 109 mm. The experimental design was randomized blocks, with four replicates, and the treatments consisted of 17 short-stature cultivars. The cultivars Catuaí Amarelo IAC 62, Catuaí Vermelho IAC 99, IAC Ouro Amarelo, Obatã IAC 1669-20, Obatã IAC 4739, Tupi IAC 1699-33, IAC 125 RN and IPR 100 stood out in terms of yield, reaching approximately 50 bags/ha. The appropriate choice of Arabica coffee cultivar in a low-altitude region may result in yield increment of up to 74%. The cultivars Catuaí Vermelho IAC 99, Tupi IAC 1699-33 and IAC 125 RN produced grains with the best quality and highest hundred-grain weight, processing yield and percentage of grains retained on sieve 17. Therefore, it is possible for an Arabica coffee cultivar to have high yield and high grain and beverage quality in a low-altitude region, promoting production alternatives for farmers.

Cyprus, an island nation situated in the Eastern Mediterranean Sea, counts among the states that elected not to adopt the 2001 UNESCO Convention on the Protection of Underwater Cultural Heritage (henceforth: the 2001 UNESCO Convention), although recognizing its merits. With a coastline of 648 km, Cyprus’ seafloor holds an abundance of underwater cultural heritage. Despite that wealth, one searches in vain for a comprehensive study on the legal protection of its underwater cultural heritage. Instead, sporadic references to some of its provisions can be traced throughout the scholarly research surrounding the legal protection of underwater cultural heritage1 and maritime archaeology.2 Against this background, this article stands as the first thorough effort to reflect on Cyprus’ legal protection of its underwater cultural heritage.

Recent years have seen an increased focus on the implementation of Preferential Trade Agreements (PTAs). While the number of PTAs has risen remarkably since early 2000, data on the utilization of preferential tariffs under these agreements point out that some businesses have not gained access to all the benefits that PTAs can provide. When utilization rates are low, the impact of the agreement will likely differ from what was anticipated by ex-ante economic research. This paper conducts a dynamic Computable General Equilibrium (CGE) analysis of the expected impact of the EU–Japan Economic Partnership Agreement and compares a scenario that includes realistic preference utilization data with a standard scenario where all tariff liberalization is assumed to be fully utilized by businesses. The results show considerable differences between the two scenarios and illustrate the need to make the inclusion of credible utilization data standard practice in the modelling of international trade.

For $r\in(0,1)$, let $\mu \left( r\right) $ be the modulus of the plane Grötzsch ring $\mathbb{B}^2\setminus[0,r]$, where $\mathbb{B}^2$ is the unit disk. In this paper, we prove that

\begin{equation*}\mu \left( r\right) =\ln \frac{4}{r}-\sum_{n=1}^{\infty }\frac{\theta _{n}}{2n}r^{2n},\end{equation*}

with $\theta _{n}\in \left( 0,1\right)$. Employing this series expansion, we obtain several absolutely monotonic and (logarithmically) completely monotonic functions involving $\mu \left( r\right) $, which yields some new results and extend certain known ones. Moreover, we give an affirmative answer to the conjecture proposed by Alzer and Richards in H. Alzer and K. Richards, On the modulus of the Grötzsch ring, J. Math. Anal. Appl. 432(1): (2015), 134–141, DOI 10.1016/j.jmaa.2015.06.057. As applications, several new sharp bounds and functional inequalities for $\mu \left( r\right) $ are established.

Uncaria rhynchophylla (Rubiaceae), a woody liana with significant medicinal value, has been used as a traditional Japanese and Chinese medicine. While effective seed production is required for breeding and efficient seedling production, the physiology of sexual reproduction remains largely unknown in this species. Therefore, we first observed the flowering behaviour, and next attempted artificial pollination using flowering individuals in a greenhouse. In this study it became clear that this species sets seeds by allogamy, but not by autogamy. The obtained seeds showed about a 90% germination rate. We also examined seed desiccation tolerance and storage conditions which are important to preserve the genetic resources. Seeds of this species were found to have a characteristic of the orthodox type, having high desiccation tolerance. Seeds after 6 months of storage at + 22, −20 and −160°C showed comparable germination rates to the seeds before storage.