Cesium transfer in short food chains

An investigation of 25,000 samples of foodstuffs and feedstuffs in Czechoslovakia, contaminated by fall-out cesium after the accident in the Chernobyl nuclear power plant, performed from May 5, 1986 to March 31, 1988, revealed that both the values of cesium transfer-factors in food--animal tissues--milk transitions and the values of biological half-life of cesium are functions of internal and external conditions of contamination. Organism individuality as the main internal condition causes the variance of about +/- 50% of the mean value of the respective transfer-factor. Through the external conditions, mainly the environmental contamination level, type of ingested food and time of ingestion, the mean values of transfer-factors are influenced up to 500%, e.g. to the value of 0.5. But this value converges with growing up contamination of food and environment to the limit of 0.3. The first two to three biological half-lives after the last ingestion of contaminated food are up to ten-times shorter than those at stabilized state.     

Pharmacokinetics and cardiopulmonary effects of guaifenesin in donkeys

Five donkeys and three horses were given guaifenesin, intravenously, by gravity administration, until recumbency was produced. The time and dose required to produce recumbency, recovery time to sternal and standing were recorded. Blood samples were collected for guaifenesin assay at 10, 20, 30, 40, 50, 60 min, and 2, 3, 4 and 6 h after guaifenesin administration. Serum was analysed for guaifenesin using HPLC and pharmacokinetic values were calculated using a computer software package (RSTRIP). In donkeys, heart and respiratory rates and blood pressures were recorded before and at 5-min intervals during recumbency. Arterial blood samples were collected before and at 5 and 15 min intervals during recumbency for analysis of pH, CO₂, and O₂. anova was used to evaluate dynamic data, while t -tests were used for kinetic values.
Respiratory rate was decreased significantly during recumbency, but no other significant changes from baseline occurred. The mean (±SD) recumbency dose of guaifenesin was 131 mg/kg (27) for donkeys and 211 mg/kg (8) for horses. Recovery time to sternal (min) was 15 (SD, 11) for donkeys and 34 (SD, 1.4) for horses. Time to standing was 32 min for donkeys and 36 min for horses. Calculation of AUC (area under the concentration–time curve) (μg.h/mL) (dose-dependent variable) was 231 (SD, 33) for donkeys and 688 (SD, 110) for horses. The clearance ( CL ) (mL/h.kg) was 546 (SD, 73) for donkeys, which was significantly different from 313 (SD, 62) for horses. Mean residence time ( MRT ) (h) was 1.2 (SD, 0.1) for donkeys and 2.6 (SD, 0.5) for horses. Volume of distribution V _d(area) (mL/kg) was 678 (SD, 92) for donkeys and 794 (SD, 25) for horses. At the rate of administration used in this study, donkeys required less guaifenesin than horses to produce recumbency, but cleared it more rapidly.     

Characteristics of paramyxoviruses isolated from pigeons in Czechoslovakia

Nine strains of paramyxovirus isolated from racing pigeons in southern Bohemia, Moravia and western Slovakia in 1983 were identified by the haemagglutination-inhibition test with antisera to seven types of paramyxovirus and three types of influenza A virus as PMV-1, Newcastle disease virus, in all cases. The haemagglutination activity and pathogenicity of the isolates for chicken embryos, chicken fibroblast cultures, and chickens of different age were determined. The mean death time of chicken embryos (MDT/MLD) was 52.8 to 95.4 h, the average being 75.7 h. The intracerebral pathogenicity index (ICPI8) was on an average 1.42 +/- 0.10 (P = 0.95). Experimental infection of chickens at the age of one, two, three and eight weeks did not cause any clinical disease but increased the level of haemagglutination-inhibiting (HI) serum antibodies up to 1 : 256 within three weeks. The course of heat inactivation of pigeon viruses at the temperature of 56 degrees C was practically identical with the inactivation of the velogenic viscerotropic strain California/1082/71. On the basis of the results, the pigeon isolates may be considered the Newcastle disease virus of velogenic viscerotropic type whose pathogenicity for chickens has been reduced to the level of mesogenic strains by long-time passaging in pigeons.     

Physiologic requirements for casein protein and wheat gluten in 4-month-old rats

Sources of casein protein and wheat gluten were analysed for the content of proteins, fats, saccharides, water and amino acids. The chemical score of the amino acids and the ratio of essential and non-essential amino acids (E/N) were determined. In rats (males) at the age of 120 days, given the diets for 14 days, the optimal and maintenance physiological daily rations were determined from the changes of body nitrogen, body water and weight dependent on the protein intake, using the method of increasing casein protein and wheat gluten content from 0 to 40 per cent in the diet. In 120-134-day-old rats, the optimal daily dose was 1.75 g of casein protein (7.5 per cent of all proteins in the diet) and 2.46 g of wheat gluten protein (10 per cent of all proteins in the diet). As to the maintenance rations determined from the weight changes, body nitrogen and body water in dependence on the protein intake, in these rats the successive daily rations were 1216 mg, 1214 mg and 1302 mg for the casein protein, and 1731 mg, 1760 mg and 1861 mg for the wheal gluten protein.     

Productivity and profitability of multistrata organic versus conventional coffee farms in Costa Rica

In areas where traditional multistrata coffee systems have been transformed to systems with patchy or no shade at all, often dependent on high chemical inputs, ecological and socioeconomic degradation has become an increasing issue. During the 1990s, rising environmental and health concerns have promoted the interest in organic production systems and their environmental services for natural resource conservation. This study compared productivity, profitability, producer-defined constraints, and goals and research priorities between ten individually paired organic and conventional coffee farms in Costa Rica. Although five of the organic farms matched or exceeded the production of their conventional counterparts, the three-year mean yield of the organic farms as a group was 22% lower than that of the conventional farms. However, excluding organic certification costs, mean variable costs and net income (NI) were similar for both groups, mainly because organic price premiums received by the farmers compensated for lower yields. If current organic certification costs are included, the price premiums paid to organic producers would have to increase to 38% in order to equal the NI from conventional coffee. Conventional farmers indentified low and unstable prices as the main constraints to sustained production and stated further intensification of production as their main goal. In contrast, the key issues for future development of the organic group centered on farm diversification, agroecological self-sufficiency, and agronomic practices that permit organic farm management. This revised version was published online in June 2006 with corrections to the Cover Date.     

Über einige in Häusern lästige Arthropodenarten

Outbreaks of some Arthropoda species in buildings of Praha are reviewed.Cylindroiolus teutonicus (Myriap., Chilopoda) leaved grassland around and entered cellars and rooms of dwelling houses. Here they died quickly in consequence of dryness. Several observations showed that Anobiidae (Anobium punctatum) living in wooden sculptures died within short after coming into central heated rooms.Lepisma saccharina damaged textil goods in a nursery school. The miteTyrophagus putrescentiae, unknown from field hitherto was often found in spider (Meta menardi) cocoons in caves and cracks of rocks.     

Applied research on multiple land use through silvopastoral system in Southern Chile

In 1977 a silvopastoral system was started in a 8.5 há farm with the typical soil characteristics of the coastal ranges of Southern Chile, planted with Radiata pine (Pinus radiata D.Don) 2/0, with a 2.5 × 7 m spacing. The sheep management system began in June 1979.The stocking rate varied from 6 to 8 sheep per há, the ewe breeds were Romney, Suffolk × Romney, with Suffolk or Romney rams. During the 1979–1982 period ratational grazing in four paddocks with native pasture and subterranean was used. Starting from June 1982 pasture area had increased to 12 há.Forage was not conserved. Overnight, sheep were kept loose on a slatted floor sheep house.D.M./há availability, sheep and lamb weight, reproduction and growth of lambs, show that the system is feasible and practical. The 1980 production was 214 kg of live weight/há; 248kg/há in 1981; 171 for 1982, and 207 for 1983. During these years the mean wool production was between 3.5 to 4 kg per sheep.The economic results f the system are attractive as to improve farmers' income, also preventing erosion, allowing a means to promote development of an important area in Southern Chile.The research project is still in progress.     

Feeding activity and life history characteristics of the generalist predator,<Emphasis Type="Italic"> Chrysoperla carnea</Emphasis> (Neuroptera: Chrysopidae) at different prey densities

Larvae of the common green lacewing, Chrysoperla carnea (Stephens) (Neuroptera :Chrysopidae) were fed with different densities of Hyalopterus pruni (Geoffer) (Homoptera: Aphididae) in Petri dishes under laboratory conditions. Functional response, developmental time, mortality rate and fecundity of the predator were measured. Treatments were carried out at 25±1°C, 65±5% RH and a 16L:8D photoperiod in a controlled temperature cabinet. Prey was given at densities of 5, 10, 20, 40, 80, 160 and 250 aphids per larva per day and the number of consumed prey, developmental time and mortality rate of the predator were recorded daily. Larvae of C. carnea responded to increasing prey densities with increasing food consumption and older larval stages displayed a higher rate of predation than younger ones. The behaviour of each of the three larval stages matched Hollings type II functional response. Larvae were able to complete their development in each of the seven prey densities, although increased prey densities reduced developmental time and mortality rate. Increased prey consumption in immature stages resulted in a higher net reproduction rate (R ₀) and the intrinsic rate of increase (r _m) of adult females.     

Radial patterns of sap flow in woody stems of dominant and understory species: scaling errors associated with positioning of sensors

We studied sap flow in dominant coniferous (Pinus sylvestris L.) and broadleaf (Populus canescens L.) species and in understory species (Prunus serotina Ehrh. and Rhododendron ponticum L.) by the heat field deformation (HFD) method. We attempted to identify possible errors arising during flow integration and scaling from single-point measurements to whole trees. Large systematic errors of -90 to 300% were found when it was assumed that sap flow was uniform over the sapwood depth. Therefore, we recommend that the radial sap flow pattern should be determined first using sensors with multiple measuring points along a stem radius followed by single-point measurements with sensors placed at a predetermined depth. Other significant errors occurred in the scaling procedure even when the sap flow radial pattern was known. These included errors associated with uncertainties in the positioning of sensors beneath the cambium (up to 15% per 1 mm error in estimated xylem depth), and differences in environmental conditions when the radial profile applied for integration was determined over the short term (up to 47% error). High temporal variation in the point-to-area correction factor along the xylem radius used for flow integration is also problematic. Compared with midday measurements, measurements of radial variation of sap flow in the morning and evening of sunny days minimized the influence of temporal variations on the point-to-area correction factor, which was especially pronounced in trees with a highly asymmetric sap flow radial pattern because of differences in functioning of the sapwood xylem layers. Positioning a single-point sensor at a depth with maximum sap flow is advantageous because of the high sensitivity of maximum sap flow to water stress conditions and changes in micro-climate, and because of the lower random errors associated with the positioning of a single-point sensor along the xylem radius.