Chemical Identification, Emission Pattern and Function of Male-Specific Pheromones Released by a Rarely Swarming Locust, Schistocerca americana

Pheromones serve key functions in the biology of swarming locusts. However, research has focused largely on the mass-swarming desert locust, Schistocerca gregaria. We extended these investigations to the pheromonal profile of the rarely swarming American bird grasshopper, S. americana (Drury). The headspace of mature gregarious S. americana males contained three characteristic electroantennogram-active components: (Z)-3-nonen-1-ol, (Z)-2-octen-1-ol, and nonanal. These substances were accompanied by aromatics such as phenol that are also released by females and immatures. Male-specific pheromone components were released independently from epidermal gland cells, with the highest emission rate being for (Z)-3-nonen-1-ol from the abdomen and legs. The emission of the major compound, (Z)-3-nonen-1-ol, is stress-sensitive, and coincides with sexual maturity and crowding. The emission pattern strongly supports a role of (Z)-3-nonen-1-ol in the reproductive biology of S. americana. The pheromone is involved in courtship-inhibition and is used as mate assessment pheromone in cryptic female choice. In double mating experiments, females choose sperm of males with high (Z)-3-nonen-1-ol emission. Furthermore the pheromone accelerated maturation of immature adults and supports synchronization of sexual development.     

Project Tocoen. The Fate of Selected Organic Compounds in the Environment. Part XXVIII. Levels of PAHs and Some Halogenated POPs in Ambient Air in Czech Republic

Abstract

Concentrations of polyaromatic hydrocarbons (PAHs), chlorinated pesticides, polychlorinated biphenyls, dibenzo-p-dioxins and dibenzo-p-furans (PCDDs/Fs) in ambient air in Ko?etice, a background locality in the South Bohemia, have been estimated in the period from July to December 1994. The 24-hours samples have been taken by the means of a high-volume sampler. Sample analysis involved Soxhlet extraction of polyurethane foam, extract preconcentration and chromatographic clean-up procedure followed by HPLC determination of PAHs with fluorescence detection, GC/ECD determination of chlorinated pollutants, and GC/MS determination of PCDDs/Fs. The results of this first detailed study undertaken in Czech Republic are compared with the data obtained by similar projects in industrial and/or urban areas in the Czech Republic and in rural or urban areas in other European countries.     

Discrimination of axonal neuropathy using sensitivity and specificity statistical measures

In needle electromyography, general mathematical methods of pattern recognition and signal analysis can be used to detect motor unit potentials and to classify various types of muscle diseases. The goal of the paper is to contribute to various methods enabling discrimination of individuals with axonal neuropathy (a positive set) from normal cases (a control set) using signals acquired from muscle activities. Data from a control set of 104 individuals and a set of 76 patients were used to validate selected methods of their separation and classification. Different features in both the time and frequency domains were studied to obtain the most reliable results . This novel approach involves comparison of individual features based on adaptive signal thresholding, as well as their combination, using supervised sigmoidal neural networks for their classification. Specificity, sensitivity and accuracy of the features used to detect individuals with axonal neuropathy was analysed using the receiver operating characteristic curves and confusion analysis. An accuracy higher than 93 % was achieved for the given sets of individuals and the optimal criterion values. The proposed modified Willison amplitude together with statistical and spectral properties of signal components classified individuals into sets of healthy and neuropathic patients by artificial neural networks with sensitivity 96.1 % and sufficient accuracy in the wide range of criterion values.     

Functional Patterning of Biopolymer Thin Films Using Enzymes and Lithographic Methods

Two different lithographic techniques for the patterning of thin biopolymer films are developed. The first method is based on using a microstructured elastomeric mold for the structuring of thin films of regenerated cellulose. The thin films are manufactured by spin‐coating of trimethylsilyl cellulose (TMSC) and subsequent regeneration. The microchannels formed by the mold and the cellulose film are filled with a cellulase solution by capillary action. In the areas exposed to the enzyme solution, the cellulose film is digested, whereas the area in contact with the mold is protected from the enzymatic activity. Optical thickness measurements, atomic force microscopy and fluorescent staining confirm a successful patterning of cellulose on several substrates by this method. The second method is based on the structured regeneration of thin TMSC films. TMSC surfaces are protected with metal masks and exposed to vapors of hydrochloric acid. These treatments result in hydrophilic cellulose structures surrounded by hydrophobic TMSC with differing physicochemical properties. Treatments of the obtained structures with cellulases allow the selective removal of pure cellulose, whereas a TMSC pattern remains on the surface. These TMSC can be regenerated back to pure cellulose by treatments with vapors of hydrochloric acid. The developed methods allow the effective fabrication of micropatterned biopolymer thin films suitable for further functionalization and application in, e.g., bioanalytical devices. This is shown by the immobilization and detection of single‐stranded DNA on structured cellulose surfaces. Owing to the versatility of both patterning approaches the methods can be further extended to other combinations of substrates and enzymes.     

The limits of flammability of mixtures of ammonia,hydrogen and methane in mixtures of nitrogen and oxygen at elevated temperatures and pressures

As part of a program investigating the flammability characteristics of ammonia in mixtures with air, nitrogen and ammonia side-products, the flammabili The flammable regions are not as large as those found in a previous study for mixtures of ammonia and hydrogen, but are still remarkably wider than the     

Prevention of combined iron-polyvitamin deficiency in female workers in the machine-building industry]

The results have been presented of the study of ferrokinetic values and providing with ascorbic and folic acids, vitamins B2 and B12 in women with latent iron deficiency, before and after preventive measures with the use of the lactic acid product "Biolact" combined with the polyvitamin "Gendevitum". The data obtained have shown that latent iron deficiency is attended by vitamin deficiency. "Biolact" enriched with iron and ascorbic acid, combined with "Gendevitum" normalizes iron metabolism and vitamin providing.     

Self-tuning geometric semantic Genetic Programming

The process of tuning the parameters that characterize evolutionary algorithms is difficult and can be time consuming. This paper presents a self-tuning algorithm for dynamically updating the crossover and mutation probabilities during a run of genetic programming. The genetic operators that are considered in this work are the geometric semantic genetic operators introduced by Moraglio et al. Differently from other existing self-tuning algorithms, the proposed one works by assigning a (different) crossover and mutation probability to each individual of the population. The experimental results we present show the appropriateness of the proposed self-tuning algorithm: on seven different test problems, the proposed algorithm finds solutions of a quality that is better than, or comparable to, the one achieved using the best known values for the geometric semantic crossover and mutation rates for the same problems. Also, we study how the mutation and crossover probabilities change during the execution of the proposed self-tuning algorithm, pointing out an interesting insight: mutation is basically the only operator used in the exploration phase, while crossover is used for exploitation, further improving good quality solutions.     

The vitamin C, B12 and folate allowances of pregnant women in Moscow]

A dietary supply of vitamins was studied in 212 pregnant women for 11 months. Mean blood levels of vitamins were found subnormal, the percentage of the women with vitamin deficiency increased. Especially inadequate was supply of folate followed by vitamin C. Intake of 1 dragee a day of polyvitamins "Gendevitum" improved the vitamin status of the examinees with the best results obtained in the first trimester. Folate and B12 levels decreased with advance of pregnancy irrespective of polyvitamins administration. Vitamin C supply was better in summer and autumn, folate levels were higher in winter and spring. It is suggested that vitamins C, B12 and folate deficiency observed in pregnancy should be corrected.