Failure of Scattering Interference in the Pseudogap State of Cuprate Superconductors

We calculate scattering interference patterns for various electronic states proposed for the pseudogap regime of the cuprate superconductors. The scattering interference models all produce patterns whose wavelength changes as a function of energy, in contradiction to the energy-independent wavelength seen by scanning tunneling microscopy (STM) experiments in the pseudogap state. This suggests that the patterns seen in STM local density of states measurements are not due to scattering interference, but are rather the result of some form of ordering.Comment: To be submitted to Phys. Rev.

Cargo Transport: Two Motors Are Sometimes Better Than One

Molecular motor proteins are crucial for the proper distribution of organelles and vesicles in cells. Much of our current understanding of how motors function stems from studies of single motors moving cargos in vitro. More recently, however, there has been mounting evidence that the cooperation of multiple motors in moving cargos and the regulation of motor–filament affinity could be key mechanisms that cells utilize to regulate cargo transport. Here, we review these recent advances and present a picture of how the different mechanisms of regulating the number of motors moving a cargo could facilitate cellular functions

Nilpotent Classical Mechanics

The formalism of nilpotent mechanics is introduced in the Lagrangian and Hamiltonian form. Systems are described using nilpotent, commuting coordinates $\eta$. Necessary geometrical notions and elements of generalized differential $\eta$-calculus are introduced. The so called $s-$geometry, in a special case when it is orthogonally related to a traceless symmetric form, shows some resemblances to the symplectic geometry. As an example of an $\eta$-system the nilpotent oscillator is introduced and its supersymmetrization considered. It is shown that the $R$-symmetry known for the Graded Superfield Oscillator (GSO) is present also here for the supersymmetric $\eta$-system. The generalized Poisson bracket for $(\eta,p)$-variables satisfies modified Leibniz rule and has nontrivial Jacobiator.Comment: 23 pages, no figures. Corrected version. 2 references adde

Studies of fluxes of dissolved iron and manganese in the Gulf of Finland

© 2004 IEEE. Metal fluxes (total dissolved iron and manganese) across the water-sediment interface were studied in situ in the Gulf of Finland in June 2002 and 2003 using an autonomous benthic lander. Distribution of these metals in the sediment and the porewater was also investigated. Focus was given to understand the behavior of the studied metals at various redox conditions and the influence when sediment resuspension is occurring. Our data indicate the importance of the redox conditions for the iron fluxes with no fluxes at oxic, intermediate at anoxic and high fluxes at suboxic conditions. The fluxes of manganese do not seem to have any correlation with the oxygen levels. Both metals were significantly affected by resuspension, which led to a rapid release

Modeling of fluid flow in pipeline and the difference scheme stability investigation

A mathematical model of viscous fluid flow in the pipeline with the presence of flow across the surface and the narrowing of pipeline section, which is based on a system of Navier-Stokes equations in two-dimensional rectangular region with a special type of boundary conditions has been designed. The geometric configuration of the leakage zone is taken into the account. It is believed that the fluid motion is under the influence of constant length of pressure difference. For the solving of this system, the numerical method of finite differences was developed by which the finite differences scheme is realized – the first step is implicit in longitudinal coordinate, and the second – on the transversal. The study on the stability of the spectral features method, stability conditions are established for the case of flow calculation with specified parameters and for the given type of the pipeline geometry. The criterion of numerical stability is presented taking to account the model’s parameters.Побудовано математичну модель течії в’язкої рідини в трубопроводі за наявності перетікання рідини через поверхню та звуження поперечного перерізу, яка базується на системі рівнянь Нав’є – Стокса в двовимірній прямокутній системі координат зі спеціальним типом граничних умов. Враховано просторову конфігурацію зон перетікання. Рух рідини здійснюється під дією постійного перепаду тиску по довжині труби. Для розв’язання задачі використано метод скінчених різниць, розроблено чисельний метод його реалізації – перший крок ітераційного процесу здійснюється по повздовжній, другий – по поперечній координатах. Вивчення стійкості проводиться за спектральною ознакою, встановлено умови стійкості для розрахунку течії зі спеціальними параметрами і для заданого типу геометрії труби. Критерії стійкості розрахунків представлено з урахуванням параметрів моделі.Построено математическую модель течения вязкой жидкости в трубопроводе при наличии перетекания жидкости через поверхность и сужения поперечного сечения, основанная на использовании двухмерной системе уравнений Навье – Стокса в прямоугольной системе координат со специальным типом граничних условий. Учтена пространственная конфигурация зон перетекания. Движение жидкости обусловлено постоянным перепадом давления по длине трубы. Для решения задачи используется метод конечних різностей, создан численный метод его реализации – первуй шаг итерационного процесса осуществляется по продольной, второй – по поперечной координатах. Изучение устойчивости проводится с использованим спектрального признака устойчивости, установлены условия устойчивости для расч.та течений со специальными параметрами и для данного типа геометрии трубы. Критерии устойчивости представлены с уч.том параметров модели

Modern means of communication in professional education

The purpose of the article is analysis of communication tools implementation in vocational education. In the course of scientific research, relevant means of communication were identified. The analysis of students' thesaurus development shows effectiveness of chosen educational tools and means in the process of professional training. Modern means of communication expand possibilities of professional training of students. Students must be ready to perform team activities, learning to conduct a professional dialogue in order to achieve the set goals

On the stability of hole crystals in layered cuprates

Recent STM measurements have revealed the existence of periodic charge modulations at the surface of certain cuprate superconductors. Here we show that the observed patterns are compatible with the formation of a three-dimensional crystal of doped holes, with space correlations extending between different Cu-O layers. This puts severe constraints on the dynamical stability of the crystallised hole structure, resulting in a close relationship between the periodicity of the electronic modulation and the interlayer distance.Comment: completed reference list, fig. 3 corrected; accepted for publication in Eur. Phys. J. B, Rapid Note

High-resolution imaging reveals indirect coordination of opposite motors and a role for LIS1 in high-load axonal transport

High-resolution particle tracking shows a specific role for the dynein regulatory factor LIS1 in high-load axonal transport of large vesicles but no evidence for mechanical activation of opposite-directed motors