A correction of E-model in quality estimation of packetized speech signal

This letter presents correction of E-model for the quality estimation of the packetized speech signal in the case of burst packet loss. The current estimation depends on the method of calculation, i.e. on the duration of speech signal segment, which is to be packetized by one packet. This inconsistency in estimation is described, and the correction of this imperfection is proposed. It is explained that the Packet-loss Robustness Factor is dependent, besides coder, on the duration of speech signal segment, which is packetized by one packet.     

Push-pull polarization conversion using novel asymmetric coupled quantum-well structures

A novel type of polarization conversion modulator, employing multiple repetitions of two novel InGaAlAs-InAlAs asymmetric coupled quantum-well structures, is proposed. The novelty of the proposed design is that, via the electrorefraction effect, it allows for a change in the TM mode's effective refractive index, which is opposite in sign to the change in the TE mode's effective refractive index. Numerical simulations based on the effective-mass envelope-function approximation show that the modulator provides not only an electrorefractive response similar to other quantum-well modulators but can also provide a low-chirp push-pull polarization modulation.     

Electrocatalysis for hydrogen electrode reactions in the light of fermi dynamics and structural bonding FACTORS-I. individual electrocatalytic properties of transition metals

The Brewer valence-bond theory for bonding in metals and intermetallic phases has been employed, together with Fermi dynamics, to correlate with the electrocatalytic properties of both individual and composite transition metal catalysts for the hydrogen electrode reactions (HELR). It has been inferred that the electrocatalytic activity of both individual transition metals and their intermetallic phases and alloys for both hydrogen evolution (HER) and its oxidation (HOR), primarily correlates with the electronic density of states and obeys typical laws of catalysis reflected in the first place in the existence of volcano plots along the Periodic Table. Since the bonding effectiveness of both individual and intermetallic hypo-hyper-d-electronic transition metal composite electrocatalysts correlates in a straightforward manner with their electrocatalytic activity, such evidence strongly suggests Fermi energy, as a typical elementary binding energy, which otherwise stays in the linear relation with cohesive energy, this forms the basis in investigation and correlation of electrocatalytic activity. Due to the fact that the Fermi wave-vector represents the individual and collective (alloys and intermetallic phases) bulk property of the available electronic number density (or its concentration, n, i.e., k_F = (3π²n) ), and in a straightforward manner correlates with the electronic density of states at the Fermi level, and thereby defines all metallic properties of a metal (and intermetallics) as “a solid with a Fermi surface”, including electrocatalytic features, it has been taken as the main parameter to correlate with the exchange current density in the hydrogen electrode reactions.     

Environment segregation of Er3+ emission in bulk sol–gel-derived SiO2–SnO2 glass ceramics

Er-doped (100-x) SiO₂–x SnO₂ glass–ceramic monoliths were prepared using a sol–gel method. Raman spectroscopic measurements showed the structural evolution of the silica matrix caused by the formation and the growth of SnO₂ nanocrystals. Analysis of the photoluminescence properties shows that the quantity of Er³⁺ ions embedded in the vicinity of SnO₂ nanocrystals could be controlled by the SnO₂ concentration. We give spectroscopic evidence of energy transfer to erbium ions provided by SnO₂ nanocrystals in the silica matrix. The ⁴I_13/2 level decay curves present a double-exponential profile with two lifetimes associated to rare-earth ions in two different environments.     

Chemical properties of the cultivated Sideritis raeseri Boiss. & Heldr. subsp. raeseri

Phytochemical analyses of the cultivated Sideritis raeseri subsp. raeseri in four different stages of flower development were performed. Traditionally used infusion and decoction were also prepared from aerial parts in full flowering stage, and analyses of active compounds and radical scavenging capacity were performed. The highest yield of the essential oil, obtained by hydrodistillation, was noticed in the full flowering phase (0.11%), with sesquiterpene bicyclogermacrene as the main constituent (42.5%). All examined extracts contained phenolic compounds and their amounts varied from 15.3 to 34.1 mg GAE/g DW. The amounts of total phenolics in infusion and decoction were similar (46.5 and 43.9 mg GAE/100 ml, respectively). LC–ESI-MS analyses of all samples allowed the characterisation of 22 phenolic compounds. Two dominant flavone glycosides, 4′-O-methylhypolaetin-7-O-[6?-O-acetyl-β-d-allopyranosyl (1 → 2)-β-d-glucopyranoside (17) and 4′-O-methylisoscutellarein-7-O-[6?-O-acetyl-β-d-allopyranosyl-(1 → 2)]-β-d-glucopyranoside (19) were quantified using HPLC. Moreover, the mineral content and the percent of transportation were investigated.     

Chemical composition and antimicrobial activity of Vitex agnus-castus L. fruits and leaves essential oils

The following study deals with the chemical composition, antimicrobial activity of essential oils of Vitex agnus-castus L. and their main constituents in vitro and in vivo. The main compounds in the oil of unripe fruits were sabinene (17.8%) and 1,8-cineole (17.5%), while in the oil of the ripe fruits dominant compounds were 1,8-cineole (16.3%) and sabinene (13.4%). The leaves oil contained an abundance of 1,8-cineole (22.0%), as well. All of the oils tested were rich sources of α-pinene (12.2%, 9.4% and 9.4%, respectively). Antimicrobial activity was tested using bacterial and fungal strains by the microdilution method. Using the same technique 1,8-cineole and α-pinene showed very high antimicrobial potency as well. As 1,8-cineole was the predominant constituent of the oils, we have chosen to test it further in an in vivo experiment. Randomly chosen apples were treated with 1,8-cineol solution and infected with Aspergillus niger in order to provoke Aspergillus rot in apples. Disease incidence was recorded.     

A brine mixing mobile unit in oil and gas industry—An example of a cost-effective,efficient, and environmentally justified technical solution

The present work shows the technical solution for a mobile unit used for brine mixing in oil and gas industry. Brine is widely used as a fluid when servicing oil and gas wells and pipelines. The use of brine in the process of pipeline overhaul allows safe operation of clogged parts of petroleum wells. In this study, we suggest a technical solution for automated production, storage, and shipping of mentioned brine. The process, methodology, equipment, and implemented “touch panel” application are innovative because they allow cost-effective, efficient, and environmentally safe preparation of brine. The primary goal of the research is to illustrate the use of the mobile unit, as well as innovative importance and usefulness of the process of mixing brine. Furthermore, its aim is to highlight the critical points and possible improvements of described technical solution.     

In vitro control of multiplication of some food-associated bacteria by thyme, rosemary and sage isolates

Antibacterial activity of thyme, rosemary and sage isolates obtained by supercritical fluid extraction and hydrodistillation was investigated on Geobacillus stearotermophillus, Bacillus cereus, Bacillus subtilis var. niger, Enterococcus faecium, Salmonella enteritidis and Escherichia coli strains. Bacillus species were the most susceptible to all tested isolates. The thyme isolates showed the strongest antibacterial activity against tested bacteria with MIC values of 40-640 μg/ml, followed by rosemary (MIC = 320-1280 μg/ml) and sage (MIC = 160-2560 μg/ml) isolates. Therefore, the antibacterial activity of the most abundant components found in the thyme isolates, thymol, p-cymene and their mixture was investigated as well. The thyme isolates, especially supercritical extract, showed stronger antibacterial activity against Bacillus strains compared to the single components and their mixture, which indicated synergetic effect of the other components. Results of this study indicated thyme as a valuable source of natural antibacterial agents and supercritical fluid extraction as an efficient isolation method.     

Comments on 'Cramer?Rao lower bound for tracking multiple targets'

In a recent paper, Ristic et al., 2004, proposed a simple and exact derivation of the theoretical Cramer-Rao lower bound (CRLB) for tracking multiple targets using intensity maps as measurements. Although the formulation and the theoretical derivations presented in their work are indeed correct, the analysis of the proposed bound and the conclusions that follow are wrong. Here, a correct analysis is presented with the key observation that [as opposed to the claim made in the work of Ristic et al. (2004)], the proposed CRLB reflects the interaction between the targets, even if their motion is independent. The multi-target CRLB is also compared with the error performance of a multi-target state maximum likelihood estimator; a remarkable agreement is observed for high signal-to-noise ratio