Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future energy resources and energy storage media. To develop a method for gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates. The thermal properties' m...

The aim of this study was to analyse the effect of the temperament of cows on their lifetime production efficiency. Data on milk performance, longevity and culling reasons of 11 629 Polish Holstein-Friesian cows were extracted from the SYMLEK database. Using the methodology of the Polish Federation of Cattle Breeders and Dairy Farmers, cow temperament was assessed as follows: 1 – calm; 2 – norm...

The purpose of the present work is to study and investigate the physiological behaviour of artificial synapses in excitable non-neural cells. We have supplied a numerical synapse model to a frog melanotrope cell by using either the current-clamp technique or a home-made easy-to-use application to achieve dynamic-clamp recordings in real time conditions. From results obtained with the convention...

In a modified FitzHugh—Nagumo model for excitable tissue a spiral wave is found to break up into an irregular spatial pattern. The main difference between our equations and the standard FitzHugh—Nagumo model is that we use two different time constants: one for the relative refractory period and another for the absolute refractory period. Breakup occurs when the relative refractory period is sho...

TiO2 thin films with a periodical two-dimensional close-packed hemispherical structure were prepared on Si substrates using pulsed laser deposition and close-packed monolayer polystyrene colloidal crystals as a template. Compared with conventional methods, which use a top-down approach, this route supports low-cost production of a periodic structure. Additionally, it is applicable to various ce...

The Domain Name System (DNS) is a critical component of the Internet infrastructure as it maps human-readable hostnames into the IP addresses the network uses to route traffic. Yet, the DNS behavior of individual clients is not well understood. In this paper, we present a characterization of DNS clients with an eye towards developing an analytical model of client interaction with the larger DNS...

The effect of small-amplitude noise on excitable systems with large time-scale separation is analyzed. It is found that small random perturbations of the fast excitatory variable result in the onset of a quasi-deterministic limit cycle behavior, absent without noise. The limit cycle is established at a critical value of the amplitude of the noise, and its period is nontrivially determined by th...

Using a combination of high resolution X-ray powder diffraction and X-ray Raman scattering spectroscopy at the B K- and Ca L2,3-edges, we analyzed the reaction products of Ca(BH4)2 after annealing at 350 °C and 400 °C under vacuum conditions. We observed the formation of nanocrystalline/amorphous CaB6 mainly and found only small contributions from amorphous B for annealing times larger than 2 h...

Stochastic fluctuations of voltage-gated ion channels generate current and voltage noise in neuronal membranes. This noise may be a critical determinant of the efficacy of information processing within neural systems. Using Monte-Carlo simulations, we carry out a systematic investigation of the relationship between channel kinetics and the resulting membrane voltage noise using a stochastic Mar...

It is well known that excitable media can sustain “fast” stable traveling pulses of excitation. In models for which analysis is tractable, the fast pulse solution is known to appear through a saddlenode bifurcation accompanied by a “slow” unstable traveling pulse. Furthermore, the uniform rest state is also a stable solution. It is generally assumed that the boundary between the basins of attra...