Crystal Phases of Charged Interlayer Excitons in van der Waals Heterostructures

Throughout the years, strongly correlated coherent states of excitons have been the subject of intense theoretical and experimental studies. This topic has recently boomed due to new emerging quantum materials such as van der Waals (vdW) bound atomically thin layers of transition metal dichalcogenides (TMDs). We analyze the collective properties of charged interlayer excitons observed recently in bilayer TMD heterostructures. We predict new strongly correlated phases - crystal and Wigner crystal - that can be selectively realized with TMD bilayers of properly chosen electron-hole effective masses by just varying their interlayer separation distance. Our results open up new avenues for nonlinear coherent control, charge transport and spinoptronics applications with quantum vdW heterostuctures.Comment: 34 pages, 8 figures, 57 reference

A Healthy and Ecologically Balanced Environment: An Argument for a Third Generation Right

Chymotrypsin-like serine proteases are found in high abundance in mast cell granules. By site-directed mutatgenesis, we have previously shown that basic amino acids in positions 143 and 192 (Arg and Lys respectively) of the human mast cell chymase are responsible for an acidic amino acid residue preference in the P2' position of substrates. In order to study the influence of these two residues in determining the specificity of chymase inhibitors, we have synthesized five different potent inhibitors of the human chymase. The inhibitory effects of these compounds were tested against the wild-type enzyme, against two single mutants Arg143Gln and Lys192Met and against a double mutant, Arg143Gln+Lys192Met. We observed a markedly reduced activity of all five inhibitors with the double mutant, indicating that these two basic residues are involved in conferring the specificity of these inhibitors. The single mutants showed an intermediate phenotype, with the strongest effect on the inhibitor by the mutation in Lys192. The Lys192 and the double mutations also affected the rate of cleavage of angiotensin I but did not seem to affect the specificity in the cleavage of the Tyr(4)-Ile(5) bond. A more detailed knowledge about which amino acids that confer the specificity of an enzyme can prove to be of major importance for development of highly specific inhibitors for the human chymase and other medically important enzymes

THE EFFECTIVENESS OF VIRTUAL MICROTEACHING CLASS IN COVID-19 PANDEMIC TIME

As a spread prevention of Covid-19 virus, schools must implement their learning process through online from Elementary School up to University including Jenderal Soedirman University. In the Covid-19 pandemic, English Education Department of Jenderal Soedirman University has already implemented Microteaching subject online or using E-Learning with the lecturer. This research uses a statistical calculation and interview data from 21 out of 31 respondents because some students have converted Microteaching credit in exchange of participation in Kampus Merdeka Program. There are 5 variables that influence Virtual Microteaching Class effectiveness. They are Enthusiasm, Learning Media, Learning Material, Task, and Lecturers’ Performance. However, the Enthusiasm variable (P=0.046) and Learning Media (P=0.020) are significant for the effectiveness of virtual Microteaching class. At the same time, other variables such as Learning Material (P=0.213), Task (P=0.166), and Lecturers’ Performance (P=0.166) are not significant for virtual Microteaching class. The effectiveness score of Virtual Microteaching Class for 6th semester students, English Education Department of Jenderal Soedirman University is 71% which means effective. The usage of Google Classroom for Virtual Microteaching Class has some disadvantages such as lack of video meeting features that most of the students need, and late notification caused by internet signal problems. As solutions to solve the problems of using Google Classroom for Virtual Microteaching class, lecturers need to explore the features of Google Classroom, and they are encouraged to use a better platform with a built-in virtual meeting and discussion features that can save large data and be downloaded at any time

Exceptional Laguerre polynomials

The aim of this paper is to present the construction of exceptional Laguerre polynomials in a systematic way, and to provide new asymptotic results on the location of the zeros. To describe the exceptional Laguerre polynomials we associate them with two partitions. We find that the use of partitions is an elegant way to express these polynomials and we restate some of their known properties in terms of partitions. We discuss the asymptotic behavior of the regular zeros and the exceptional zeros of exceptional Laguerre polynomials as the degree tends to infinity.Comment: To appear in Studies in Applied Mathematic

A Direct Method for Modeling and Simulations of Elliptic and Parabolic Interface Problems

Interface problems have many applications in fluid dynamics, molecular biology, electromagnetism, material science, heat distribution in engines, and hyperthermia treatment of cancer. Mathematically, interface problems commonly lead to partial differential equations (PDE) whose in- put data are discontinuous or singular across the interfaces in the solution domain. Many standard numerical methods designed for smooth solutions poorly work for interface problems as solutions of the interface problems are mostly non-smoothness or discontinuous. Moving interface problems depends on the accuracy of the gradient of the solution at the interface. Therefore, it became essential to derive a method for interface problems that gives second-order accuracy for both the solution and its gradients. As most applications in the real world are in 3D settings, the development of three-dimensional elliptic interface solvers and the study of their convergence is significant. We have developed a novel Direct Method for solving three-dimensional elliptic interface problems that preserve the discontinues in solution and gradient across the interface. The method uses a standard seven-point central difference scheme at regular grid points and a compact twenty-seven-point scheme only at irregular grid points by incorporating the interface\u27s jump conditions. The model was implemented using both MATLAB and FORTRAN routines and showed that the computed solution and gradient of the solution near the interface are second-order accurate in infinity norm. We also have modified the developed direct method to solve the 3D heat equation with fixed interfaces. Numerical results showed that the proposed method is unconditionally stable and is second-order accurate in both time and space.https://digitalcommons.odu.edu/gradposters2021_sciences/1007/thumbnail.jp

Social Innovation for Active Ageing (SIFAA)

Age-related loneliness is a major social issue as it is increasing alongside an upward global population trend which predicts that nearly 22% of the world population will be aged 60 years or over by 2050 (Rutherford, 2012). This ‘silver tsunami’ (Cacioppo and Patrick, 2008) represents an unprecedented growth of the elderly population and is likely to exert socio-economic pressure globally in the form of healthcare needs etc. (Dychtwald and Flower, 1989, O'Connor, 2014). Recent surveys conducted in many parts of the world such as the USA, the UK and Japan etc. reveal this plight of the elderly as many older people report feeling lonely ‘often’ (Hawkley and Cacioppo, 2007, Marsh, 2014, Kim et al., 2009). The examination of current methods and techniques aimed at combating age-related loneliness in order to recognise any ‘patterns’ (Alexander et al., 1977) reveals that the current thinking around developing such interventions predominantly adopts an incremental approach (Sharma et al., 2015). Sharma et al. highlight a gap in knowledge exemplified by the lack of radical-digital interventions, and suggest that more experimentation is required in this area to under- stand the strengths, or more to the point the limitations of radical-digital interventions (2015). In this poster, we recognise that the Activity Theory of Ageing (ATA) (Havighurst, 1961) provides a good foundation for developing effective strategies for tackling loneliness amongst older adults and we highlight its potential and restraints in this area. We propose that its fixation on the individual as the ‘unit of analysis’ (McClelland, 1982) can be eased by combining it with Social Innovation. We examine both these theoretical frameworks to discuss how a hybridisation of ATA and Social Innovation can allow for a significant movement away from the dominant incremental approach developing loneliness-interventions. We call this hybrid approach Social Innovation for Active Ageing (SIFAA)

On Making a Marriage, an Inst., or a Society

Every Mao needs a Chou En-Lai in marriages, institutes, and societies