Anxiety-like behavioural effects of extremely low-frequency electromagnetic field in rats

In recent years, extremely low-frequency electromagnetic field (ELF-EMF) has received considerable attention for its potential biological effects. Numerous studies have shown the role of ELF-EMF in behaviour modulation. The aim of this study was to investigate the effect of short-term ELF-EMF (50 Hz) in the development of anxiety-like behaviour in rats through change hypothalamic oxidative stress and NO. Ten adult male rats (Wistar albino) were divided in two groups: control group—without exposure to ELF-EMF and experimental group—exposed to ELF-EMF during 7 days. After the exposure, time open field test and elevated plus maze were used to evaluate the anxiety-like behaviour of rats. Upon completion of the behavioural tests, concentrations of superoxide anion (O₂·^?), nitrite (NO₂ ^?, as an indicator of NO) and peroxynitrite (ONOO^?) were determined in the hypothalamus of the animals. Obtained results show that ELF-EMF both induces anxiety-like behaviour and increases concentrations of O₂·^? and NO, whereas it did not effect on ONOO^? concentration in hypothalamus of rats. In conclusion, the development of anxiety-like behaviour is mediated by oxidative stress and increased NO concentration in hypothalamus of rats exposed to ELF-EMF during 7 days.     

Effects of composted sewage sludge on microbial biomass, activity and pine seedlings in nursery forest

The investigation was carried out in a 2 year experiment to evaluate the benefits and hazards of the use of composted sewage sludge as a restoration agent for the soil of the nursery forest intended for growing Pinus sylvestris seedlings. The grey forest soil (Haplic Greyzem) was amended with compost at the 25, 50, 75, 100, 150 and 175 t ha(-1) application rates on a dry matter basis. The organic matter content increased with the increase in sludge amendment as well as the metal content. However, the concentrations of individual metals were below the current limits established for Russia and European countries. Sludge amendments enhanced the germination and decreased the mortality of the seedlings. The effects were more obvious for the soil with the highest sludge treatment. The beneficial effects on the biomass of seedlings and the height of the shoots as well as on the length of the roots of the pine seedlings were greater in plots with the highest rates of composted sludge. The application of composted sludge to soil was followed by an increase in microbial biomass and to a lesser extent in basal respiration. In the absence of any detrimental effect on microorganisms, this study lends support to using composted sewage sludge as the organo-mineral fertilizer for the soil of nursery forest.     

The Effects of Ammonia on SO2 Emissions in a Fluidized Bed Combustor Under Pseudo-Staged Combustion

The reduction of SO₂ by ammonia gas additionduring staged combustion of bituminous coal has beenstudied in a 2 m high fluidized bed combustor of 30 cmstatic bed height and a freeboard height of 100 cm.The coal was introduced to the combustor at 42 cmabove the distributor and the ammonia gas was injectedat 52 cm above the distributor by an uncooledstainless steel injector. Experiments were carriedout to investigate effects of ammonia gas injection onSO₂ emissions of (i) air staged levels, (ii) excess air levels, (iii) primary air factor, PAF(ratio of primary to stoichiometric air), (iv) NH₃:SO₂ molar ratio, and (v) fluidizingvelocity. Experiments were carried out under a newtechnique of air staging called Pseudo-stagedCombustion, maintaining the excess air level andfluidizing velocity between 17 and 70% and between0.7 and 2.0 m sec^-1, respectively. A maximum reduction of92% was obtained at 37% excess air, at NH₃:SO₂ molar ratio of 5.5. The effective NH₃:SO₂ molar ratio was found to be between 3.0 and5.5, which is true for all staging and excess air levels.A greater removal of SO₂ with NH₃ injectionduring staged combustion is probably due to this newstaging technique. The Pseudo-staging reducestemperature through the freeboard and flue for theoccurance of as NH₃ + SO₂ reactions. Thesereactions are reported to be low temperaturereactions. The NH₃ carry over was less than 83 ppm for all operating conditions. The present studydemonstrates that staged combustion coupled withammonia injection can reduce SO₂ emissions.     

An experimental method to verify soil conservation by check dams on the Loess Plateau, China

A successful experiment with a physical model requires necessary conditions of similarity. This study presents an experimental method with a semi-scale physical model. The model is used to monitor and verify soil conservation by check dams in a small watershed on the Loess Plateau of China. During experiments, the model–prototype ratio of geomorphic variables was kept constant under each rainfall event. Consequently, experimental data are available for verification of soil erosion processes in the field and for predicting soil loss in a model watershed with check dams. Thus, it can predict the amount of soil loss in a catchment. This study also mentions four criteria: similarities of watershed geometry, grain size and bare land, Froude number (Fr) for rainfall event, and soil erosion in downscaled models. The efficacy of the proposed method was confirmed using these criteria in two different downscaled model experiments. The B-Model, a large scale model, simulates watershed prototype. The two small scale models, D_a and D_b, have different erosion rates, but are the same size. These two models simulate hydraulic processes in the B-Model. Experiment results show that while soil loss in the small scale models was converted by multiplying the soil loss scale number, it was very close to that of the B-Model. Obviously, with a semi-scale physical model, experiments are available to verify and predict soil loss in a small watershed area with check dam system on the Loess Plateau, China.     

Soil Quality Evolution After Land Use Change From Paddy Soil to Vegetable Land

A survey was done in 15 typical villages, 150 soil and 86 vegetable plant samples were taken in Jiaxin prefecture of the Taihu Lake region, northern Zhejian province. Results indicate that after 15–20 years land use changed from the paddy rice–wheat (or oilseed rape) double cropping system, to a continuous vegetable land has caused soil quality dramatic change. (1) Acidification: average soil pH was 5.4; about 61% of total samples were pH < 5.5. It was 0.9 units lower than 10 years ago with same upland vegetable cultivation and was 1.2 units lower than soil pH of paddy rice–wheat (or oilseed rape) rotation. (2) Fertilizer salt accumulation: the average salt content was 0.28%, among these about 36.2% of the total samples contained more than 0.3%. (3) Nitrate N and available phosphorus (P) over accumulation: on average it was 279 mg NO₃-N/kg, and 45–115 mg P/kg. Nitrate N four times higher and available P 4–10 times more than it is in present paddy rice–wheat rotation soils respectively. This has caused wide concern because of possible groundwater and well drinking water pollution by leached nitrate N and the P losses to water by runoff from vegetable lands induce surface water eutrophication.     

Heavy metal concentrations in soils and plant accumulation in a restored manganese mineland in Guangxi, South China

Heavy metal contamination of metal-mined soils is a widespread problem in China. In the restored (over 20 years) Lipu manganese mineland, 36 plant species from 22 families were found colonizing, some of which were planted agronomic ones. Heavy metal concentrations in tailings were very high. Minesoils were basically unpolluted, but soils in the remaining mining area and in the vicinity of tailings dumps were polluted by Cd and Mn. Measurements of metal contents in dominant plants showed they were close to those of other mineland plants. Plants tended to have a higher Cd accumulation (as reflected by Biological Accumulation Coefficient) from soil, but have a higher Mn translocation (as indicated by Biological Transfer Coefficient) to aboveground parts. The Chinese chestnut and sugarcane cultivated on the reclaimed mineland were not safe for human consumption, and this agricultural restoration pattern should be carefully reconsidered.     

The individual and combined effects of ozone and simulated acid rain on growth, gas exchange rate and water-use efficiency of Pinus armandi Franch

The seedlings of Pinus armandi Franch. were exposed to ozone (O(3)) at 300 ppb for 8 h a day, 6 days a week, and simulated acid rain of pH 3.0 or 2.3, 6 times a week, alone or in combination, for 14 weeks from 15 June to 20 September 1993. The control seedlings were exposed to charcoal-filtered air and simulated rain of pH 6.8 during the same period. Significant interactive effects of O(3) and simulated acid rain on whole plant net photosynthetic rate were observed, but not on other determined parameters. The exposure of the seedlings to O(3) caused the reductions in the dry weight growth, root dry weight relative to the whole plant dry weight, net photosynthetic rate, transpiration rate in light, water-use efficiency and root respiration activity, and increases in shoot/root ratio, and leaf dry weight relative to the whole plant dry weight without an appearance of acute visible foliar injury, but did not affect the dark respiration rate and transpiration rate in the darkness. The decreased net photosynthetic rate was considered to be the major cause for the growth reduction of the seedlings exposed to O(3). On the other hand, the exposure of the seedlings to simulated acid rain reduced the net photosynthetic rate per unit chlorophyll a + b content, but did not induce the significant change in other determined parameters.     

Failure case studies of SA213-T22 steel tubes of boiler through computer simulations

Increased temperature and decreased hardness values of the tube metal and development of oxide scale on the inner surface of boiler tubes over prolonged period of time are typical problems in power plants. Appropriate life assessments or condition monitoring of boiler tube should be carried out from time to time. Computer simulations may economically support the post-failure assessment method, i.e. visual inspections, metallurgical examinations and mechanical strength measurements. However, estimations obtained from the simulations may provide an advanced warning to take preventive actions prior to failure. In this work two failure cases of the reheater and superheater tubes made of a typical material of SA213-T22 steel are evaluated. As the oxide scales are increasingly developed on the inner surface, the increasing of temperature and decreasing of hardness value in tube metal for both cases are determined. The remnant life estimations are then made in the form of creep cumulative damages.     

Functional Ecosystems and Biodiversity Buzzwords

Abstract: Several increasingly popular paradigms in conservation remove organismal information and life-history requirements from management planning with claims that species-specific information is not necessary to the understanding and management of "ecosystem function" and may therefore be discarded. Although several authors have called attention to the fact that ecosystem management has not yet been articulated sufficiently to comprise an adequate paradigm for wildlife protection, there has been a series of suggestions paralleling ecosystem management's popularity that the perceived or imagined emergent properties of communities should be at the root of conservation planning. Such reductions most commonly take the form of abstracted species diversity measures that may be irrelevant or misleading with respect to site-specific planning and to the monitoring of specific management treatments. Following earlier examinations of ecosystem management, I emphasize that several of its apparent outgrowths may be too vague to inform specific recommendations, that the historical mechanics of "ecosystem processes" are essentially unknowable, and that anecdotal definitions of ecosystems allow one to justify virtually any protocol as management. The primacy of process-dependent, landscape-functional considerations in conservation planning is specious in the absence of species- and population-specific information, which should form the foundation for understanding such processes in the first place. Only by viewing nature in terms of the relationships between processes and organisms, rather than in terms of emergent properties of organismal assemblages or abiotic factors divorced from organismal data, can conservation plans claim to protect biological elements.