The effects of breed,sex, intramuscular fat and ultimate pH on pork tenderness

A study was conducted to evaluate the influence of breed and sex of animals on tenderness of pork. For evaluation, carcasses of pure breed barrows and gilts of Large White, Czech pig meat, Landrace and Duroc were used. For laboratory investigations, the samples of musculus longissimus lumborum et thoracis (20 mm thick) were taken from the same place, at the first cruciate vertebra 48 h post mortem. Seven days post mortem, the texture of heat-processed meat was measured objectively by the shear method on Instron equipped with Warner–Bratzler shear device. Meat tenderness and juiciness were also evaluated sensorially. It was observed that the tenderness of cooked meat is influenced by breed (the tenderest meat was from Duroc breed). The sex of animals has significant effect on meat tenderness too. At the same time, the effects of pH 45 minutes (pH₄₅) and 24 hours (pH₂₄) post mortem and intramuscular fat content on meat tenderness were evaluated. Correlations were found between shear force (tenderness) and intramuscular fat content and also between shear force and pH value 45 min post mortem. The shear force decreased with increasing intramuscular fat content and with increasing pH₄₅ value. Sensory evaluation of tenderness confirmed the objectively measured data.     

Development,construction, and use of pneumometric tubes for measurement of steam flow in the steam lines of PVG-1000 at NPP

A system for the direct measurement of steam flow in steam lines after a steam generator, which utilizes a special design of pneumometric tubes and a computing unit that accounts for variation in steam pressure, has been developed to improve the quality of water-level regulation in the steam generators of VVéR-1000 power-generating units in the stationary and transitional modes. The advantage of the pneumometric tubes consists in their structural simplicity, high erosion resistance, and absence of irrevocable losses during measurement of steam flow. A similar measurement system is used at foreign NPP. The measurement system in question has been placed in experimental service at the No. 3 unit of the Balakovo NPP, and has demonstrated its worthiness. This measurement system can also be used to determine steam flow in the steam lines of NPP units with VVéR-1000 and VVéR-440 reactors, and PBMK-1000 power-generating units. __________ Translated from élektricheskie Stantsii, No. 3, March 2007, pp. 23–26.     

Prevalence of thermotolerant Campylobacter spp. in broilers at retail in the Czech Republic and their antibiotic resistance

Infections caused by thermotolerant Campylobacter spp. are among the most frequent bacterial diseases from food in Europe. An important source of infection is poultry. The aim was to perform the first nationwide study on the prevalence of Campylobacter spp. at retail in the Czech Republic. Samples of chilled and frozen broiler chickens were obtained from supermarkets localized in the eight largest cities in the Czech Republic. From February to November 2009, a total of 120 samples of chilled and 120 samples of frozen poultry were collected and assessed. Qualitative and quantitative analyses were performed according to the ISO 10272-1:2006 and ISO 10272-2:2006 methods. The microdilution method was used to test the resistance of Campylobacter spp. isolates to selected antibiotics. High prevalence of Campylobacter spp. was detected in chilled poultry (75%). The prevalence was significantly lower (37%) in frozen poultry. The most prevalent species was Campylobacter jejuni detected in 70% of positive findings, followed by Campylobacter coli (18%). In 12% of cases, the samples were contaminated by both C. jejuni and C. coli. The species Campylobacter lari and Campylobacter upsaliensis were not detected. The highest resistance rates were to quinolone antibiotics and ampicillin.     

Study of fatty acid composition of cell membranes during the use of soya oil in diet therapy of patients with cardiovascular diseases

Anti-atherogenic diet supplemented with 20 g soy oil has been analyzed in patients with coronary artery disease and high blood pressure. The vegetable PUFA omega-3 and omega-6 from soy oil have been found to change physical, biological and chemical property of membranes; improved clinical condition as well as to modify erythrocyte membrane fatty acid composition.     

Impacts of Climate Variables on Residential Water Consumption in the Czech Republic

The paper investigates whether there is a statistically significant impact of short-term climate variables (specifically air temperature and rainfall) on residential water consumption at two selected case sites in the Czech Republic. The analysis is based on a unique time series of daily data from 2004–2009. The statistical methods used are CART methodology and a decomposition of these time series based on a locally weighted regression method. Apart from the data analysis results, the investigation raises several methodological questions regarding the use of daily data and the scope of analysis based on such data sets.     

1/<Emphasis Type="Italic">f</Emphasis> noise in metal insulator semiconductor transistors with different conductivity types and different topological dimensions of the channel

An experimental investigation of 1/f noise in metal insulator semiconductor transistors with different types of channel conductivity and different topological sizes of the gate region is presented. The transistors are produced on the basis of the standard 1.2-μm complementary metal oxide semiconductor technology and can be used as reading elements in 2D multielement detectors of infrared radiation. The level of 1/f noise is determined in relation with the channel conductivity type. It is shown that the p-channel transistors exhibit a lower level of 1/f noise compared to that of the n-channel transistors (by about one order of magnitude). The dependence of 1/f noise on the topological size of the gate region is obtained. The transistors with the smallest channel width are found to produce the highest noise level.     

A layer radiowave absorber based on double-period lattices of resistive squares

A radiowave-absorbing composite material based on double-period lattices of resistive squares is considered. Methods of the electric circuit and long line theories are applied to obtain expressions for the estimate of the effective permittivity of such a composite. It is shown that the frequency dependence of the effective permittivity of the realized composite is close to the relaxation value. The reflection characteristics of a radiowave absorber based on a composite with double-period lattices of resistive squares are investigated. It is found that, for such a radiowave absorber, the ratio of the difference of the extreme wavelengths of its operating band (corresponding to the minus-10-dB reflection level) to the thickness of the radiowave absorber is within an interval of 4.2–4.5.     

The electronic educational resource “Dynamics of Systems for Controlling Thermal Processes”

We present the results from the development of a cycle of tutorial laboratory works for remote education under the general title “Dynamics of Systems for Controlling Thermal Process” for students specializing in the discipline of automation of technological processes and production facilities worked out on the basis of the Matlab software package and the Simulink environment for development of simulation models.     

Finning efficiency of a metal-hydride reactor’s active volume

The results of numerical simulation of hydrogen sorption/desorption processes in the metal-hydride device intended for hydrogen storage has been presented. It is shown that it is possible to improve sufficiently the dynamics of sorption/desorption process using relatively “dense” finning. In this case an active volume of the reactor decreases considerably.