Back-reaction of perturbation wave packets on gray solitons

Within the Bogoliubov-de Gennes linearization theory of quantum or classical perturbations around a background solution to the one-dimensional nonlinear Schr\"odinger equation, we study the back-reaction of wave packet perturbations on a gray soliton background. From our recently published exact solutions, we determine that a wave packet effectively jumps ahead as it passes through a soliton, emerging with a wavelength-dependent forward translation in comparison to its motion in absence of the soliton. From this and from the full theory's exact momentum conservation, we deduce that post-Bogoliubov back-reaction must include a commensurate forward advance by the soliton itself. We quantify this effect with a simple theory, and confirm that it agrees with full numerical solution of the classical nonlinear Schr\"odinger equation. We briefly discuss the implications of this effect for quantum behavior of solitons in quasi-condensed dilute gases at finite temperature.Comment: 12 pages, 2 figure

Does the Culture of Honor do well in Poland? A Replication Study on the Culture of Honor while Accounting For Gender Role Differences.

This paper deals with the issue of honor culture in Poland. In a traditional honor culture, honorable men should be sensitive to situations where their honor is defiled. They should also be ready to defend their good name (Cohen and Nisbett, 1997), even if it means using violence. In such a culture women cannot actively defend their honor. The authors checked the gender role differences (both in actor and observer perspective) in attitudes towards honorable behaviors. The paper presents two experiments, analyzed with repeated ANOVA measures. In the first study, which is a replication of the research conducted by Szmajke (1999), men and women (N=156) evaluated a letter written by an "honorable" killer and a "dishonorable" thief (in two gender versions). The second study (N=146) replicated the results of the first one.The results confirm the traditional concept of the culture of honor as a permission for aggression used by men to defend their good name, in the eyes of both women and men. The use of violence by women in an analogues situation is evaluated negatively by both genders. Results shows that the general gender roles in Polish culture of honor keeps men as active user of violence to respond for the provacation. Women are not allowed to active violent defend of their honor

Cross-border virtual teams, as seen from applied psychology & applied economy perspective. A Case study of a cross-cultural teaching program

As communication becomes easier with the proliferation of ICT (Internet Communication Technology), more companies and individuals face the need and challenge of creating and facilitating virtual teams. Those are groups of people that contact each other only by the means of the internet, with no real-world physical face-to-face contact. Despite the numerous benefits, as low-to-non monetary costs and enormous creation flexibility, there are also many (psychological) risks, often not apparent from the outside. In the current paper we discuss the teaching program that was designed to foster virtual communication skills. We describe a project conducted simultaneously between Palacký University (Olomouc, CZ) and University of Opole (Opole, PL) in the summer term of 2015. We argue that such classes have a potential for individual and business development, provided the necessary preparations are made.Podczas gdy komunikacja staje się coraz łatwiejsza dzięki rozprzestrzenianiu się technologii komunikacji przez Internet (ICT), coraz więcej firm i osób staje przed wyzwaniem (współ)tworzenia i zwiększania efektywności wirtualnych zespołów. Chodzi tutaj o grupy ludzi kontaktujące się między sobą wyłącznie przez Internet, bez kontaktów w realnym świecie. Pomimo licznych zalet, do których należą między innymi niskie lub wręcz zerowe koszty finansowe oraz niezwykła elastyczność tworzenia, przed wirtualnymi zespołami istnieje też wiele wyzwań, nie widocznych z zewnątrz. W bieżącym artykule omawiamy zalety programu zajęć, zaprojektowanego do wzmacniania umiejętności komunikacji w wirtualnych zespołach. Opisujemy projekt dydaktyczny zrealizowany jednocześnie pomiędzy Uniwersytetem Palackiego (Olomouc, CZ) i Uniwersytetem Opolskim (Opole, PL) w semestrze letnim w roku 2015. Argumentujemy, iż taki program może przynieść korzyści zarówno z perspektyw jednostkowej, jak i biznesowej, pod warunkiem podjęcia odpowiednich przygotowań

Electron transport through multilevel quantum dot

Quantum transport properties through some multilevel quantum dots sandwiched between two metallic contacts are investigated by the use of Green's function technique. Here we do parametric calculations, based on the tight-binding model, to study the transport properties through such bridge systems. The electron transport properties are significantly influenced by (a) number of quantized energy levels in the dots, (b) dot-to-electrode coupling strength, (c) location of the equilibrium Fermi energy $E_F$ and (d) surface disorder. In the limit of weak-coupling, the conductance ($g$) shows sharp resonant peaks associated with the quantized energy levels in the dots, while, they get substantial broadening in the strong-coupling limit. The behavior of the electron transfer through these systems becomes much more clearly visible from our study of current-voltage ($I$-$V$) characteristics. In this context we also describe the noise power of current fluctuations ($S$) and determine the Fano factor ($F$) which provides an important information about the electron correlation among the charge carriers. Finally, we explore a novel transport phenomenon by studying the surface disorder effect in which the current amplitude increases with the increase of the surface disorder strength in the strong disorder regime, while, the amplitude decreases in the limit of weak disorder. Such an anomalous behavior is completely opposite to that of bulk disordered system where the current amplitude always decreases with the disorder strength. It is also observed that the current amplitude strongly depends on the system size which reveals the finite quantum size effect.Comment: 12 pages, 7 figure

A mesoscopic ring as a XNOR gate: An exact result

We describe XNOR gate response in a mesoscopic ring threaded by a magnetic flux $\phi$. The ring is attached symmetrically to two semi-infinite one-dimensional metallic electrodes and two gate voltages, viz, $V_a$ and $V_b$, are applied in one arm of the ring which are treated as the inputs of the XNOR gate. The calculations are based on the tight-binding model and the Green's function method, which numerically compute the conductance-energy and current-voltage characteristics as functions of the ring-to-electrode coupling strength, magnetic flux and gate voltages. Our theoretical study shows that, for a particular value of $\phi$ ($=\phi_0/2$) ($\phi_0=ch/e$, the elementary flux-quantum), a high output current (1) (in the logical sense) appears if both the two inputs to the gate are the same, while if one but not both inputs are high (1), a low output current (0) results. It clearly exhibits the XNOR gate behavior and this aspect may be utilized in designing an electronic logic gate.Comment: 8 pages, 5 figure

Stochastic Simulations of the Repressilator Circuit

The genetic repressilator circuit consists of three transcription factors, or repressors, which negatively regulate each other in a cyclic manner. This circuit was synthetically constructed on plasmids in {\it Escherichia coli} and was found to exhibit oscillations in the concentrations of the three repressors. Since the repressors and their binding sites often appear in low copy numbers, the oscillations are noisy and irregular. Therefore, the repressilator circuit cannot be fully analyzed using deterministic methods such as rate-equations. Here we perform stochastic analysis of the repressilator circuit using the master equation and Monte Carlo simulations. It is found that fluctuations modify the range of conditions in which oscillations appear as well as their amplitude and period, compared to the deterministic equations. The deterministic and stochastic approaches coincide only in the limit in which all the relevant components, including free proteins, plasmids and bound proteins, appear in high copy numbers. We also find that subtle features such as cooperative binding and bound-repressor degradation strongly affect the existence and properties of the oscillations.Comment: Accepted to PR

Measuring the sequence-affinity landscape of antibodies with massively parallel titration curves

Despite the central role that antibodies play in the adaptive immune system and in biotechnology, much remains unknown about the quantitative relationship between an antibody's amino acid sequence and its antigen binding affinity. Here we describe a new experimental approach, called Tite-Seq, that is capable of measuring binding titration curves and corresponding affinities for thousands of variant antibodies in parallel. The measurement of titration curves eliminates the confounding effects of antibody expression and stability that arise in standard deep mutational scanning assays. We demonstrate Tite-Seq on the CDR1H and CDR3H regions of a well-studied scFv antibody. Our data shed light on the structural basis for antigen binding affinity and suggests a role for secondary CDR loops in establishing antibody stability. Tite-Seq fills a large gap in the ability to measure critical aspects of the adaptive immune system, and can be readily used for studying sequence-affinity landscapes in other protein systems