Signal processing and wavelet analysis of simultaneously registered blood pressure and laser Doppler flow signals during extremely low frequency electromagnetic field exposure in humans in vivo

Regulation of microcirculation and other physiological processes have strong non-linear character and involves complex of different processes, every process with own hierarchy in time and different frequencies. Traditional Fourier analysis does not provide sufficient power and resolution to elucidate characteristic of low vasomotor frequencies. Therefore, we apply a Time–frequency (wavelet) analysis on the signal obtained by Laser Doppler flow meter (LDF) at 25 healthy volunteers, exposed at the same time to low frequency electromagnetic fields, used for physiotherapy. Signal processing include Matlab based algorithms for digital signal processing (DSP) and Matlab Spectral analysis toolbox of simultaneous registered variations in Blood Pressure (BP), Laser Doppler Flow (LDF), and Intravital microscopy (IVM). It provides useful information about regulatory mechanisms and vegetative nervous system regulation of peripheral blood flow. Continuous changes in blood pressure variations and perfusion of extremities were measured prior and after 10, 20, and 30 min ELF-EMF (10, 16, 20, and 30 mT), exposure. After wavelet analysis of the blood flow signals and vasomotion changes signals, several frequency bands were distinguished: 0.0095–0.02 Hz; (α), 0.02–0.06 Hz; (β), 0.06–0.15 Hz; (γ), 0.15–0.4 Hz; (δ), and 0.4–1 Hz; (θ) for LDF data and 0.0095–0.4 Hz; (α), 0.4–0.75 Hz; (β), 0.75–0.9 Hz; (γ), 0.9–1.2 Hz; (δ), and 1.2–2 Hz; (θ) for IVM data. In this study, overlapping of some frequency bands between IVM and LDF data were found. Overlapping of the frequency bands has two ways of interpretation, one related with similarity of the structures and tissues and other related with output of ELF-EMF stimulation. We used also correlation and cross-correlation analysis to compare non-invasive (BP measurements and LDF) data, with invasive intravital microscopy (IVM) data (obtained on animals in vivo), during ELF-EMF stimulation. IVM data were used as a reference value, for certain information of possible mechanisms of biological response at the tissue and blood vessel level after ELF-EMF exposure with frequency in the range from 10 to 50 Hz and magnetic flux density of 20 mT. Comparative analysis of IVM and LDF, frequency bands show that they have statistical significant changes after ELF-EMF stimulation. Five subintervals were confirmed (α-, β-, γ-, δ-, and θ). The findings indicate that local ELF-EMF exposure at the constant temperature of the media increases skin blood flow at the upper extremities which have a contribution to the α-frequency band at IVM.     

Characterizing the Relative Contributions of Large Vessels to Total Ocean Noise Fields: A Case Study Using the Gerry E. Studds Stellwagen Bank National Marine Sanctuary

In 2006, we used the U.S. Coast Guard’s Automatic Identification System (AIS) to describe patterns of large commercial ship traffic within a U.S. National Marine Sanctuary located off the coast of Massachusetts. We found that 541 large commercial vessels transited the greater sanctuary 3413 times during the year. Cargo ships, tankers, and tug/tows constituted 78% of the vessels and 82% of the total transits. Cargo ships, tankers, and cruise ships predominantly used the designated Boston Traffic Separation Scheme, while tug/tow traffic was concentrated in the western and northern portions of the sanctuary. We combined AIS data with low-frequency acoustic data from an array of nine autonomous recording units analyzed for 2 months in 2006. Analysis of received sound levels (10–1000 Hz, root-mean-square pressure re 1 μPa ± SE) averaged 119.5 ± 0.3 dB at high-traffic locations. High-traffic locations experienced double the acoustic power of less trafficked locations for the majority of the time period analyzed. Average source level estimates (71–141 Hz, root-mean-square pressure re 1 μPa ± SE) for individual vessels ranged from 158 ± 2 dB (research vessel) to 186 ± 2 dB (oil tanker). Tankers were estimated to contribute 2 times more acoustic power to the region than cargo ships, and more than 100 times more than research vessels. Our results indicate that noise produced by large commercial vessels was at levels and within frequencies that warrant concern among managers regarding the ability of endangered whales to maintain acoustic contact within greater sanctuary waters. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Influence of a 1,800 MHz electromagnetic field on the EEG energy

The present study investigated the influence of electromagnetic fields (EMF), similar to that emitted by mobile phones, on brain activity. Ten women and ten men, matched for age and educational level, performed a short memory task (Wechsler test), with simultaneous Electroencephalogram (EEG) recordings at 15 scalp electrodes, both without (baseline) and with exposure to an 1,800 MHz signal. The EEG energy was found concentrated at the four basic EEG bands [α (8–13 Hz), β (14–30 Hz), δ (0–4 Hz), and θ (5–7 Hz)]. The analysis revealed that in the presence of EMF, the energy of the β band was significantly greater for females than for males at the majority of the electrodes. Since beta oscillation is associated with the shift of attention during the perception, these findings may indicate that the particular EMF (1,800 MHz signal) exerts an influence on this brain activity, which appears to be gender-related.     

Effect of modulated microwave radiation on human EEG asymmetry

This study is aimed to investigation of the effect of modulated 450 MHz microwave radiation on the EEG inter-hemispheric asymmetry. Ten cycles of the microwave exposure (1 min off and 1 min on) at fixed modulation frequency were applied on two groups of healthy volunteers. The first group of 13 subjects was exposed to microwave radiation modulated at 14 Hz and the second group of 15 subjects at 40 Hz frequency. The peak specific absorption rate (SAR) average over 1 g was 0.303 W/kg. Differences in SAR between hemispheres were up to 20 dB. Rod antenna was located from the left side of the head. Differences of relative changes in EEG energy between symmetric channels FP1–FP2, T3–T4, P3–P4 and O1–O2 in exposed and sham conditions were analysed. The results showed increase in EEG energy from the left side caused by microwave exposure. Statistical analysis done for the whole group of subjects didn’t reveal significant differences in inter-hemispheres asymmetry between exposed and sham conditions. However, statistical analysis performed for individual subjects detected significant differences in asymmetry caused by exposure for 15–35% of individuals.     

Effects of Sea-Level Rise and Anthropogenic Development on Priority Bird Species Habitats in Coastal Georgia, USA

We modeled changes in area of five habitats, tidal-freshwater forest, salt marsh, maritime shrub-scrub (shrub), maritime broadleaf forest (oak) and maritime narrowleaf (pine) forest, in coastal Georgia, USA, to evaluate how simultaneous habitat loss due to predicted changes in sea level rise (SLR) and urban development will affect priority bird species of the south Atlantic coastal plain by 2100. Development rates, based on regional growth plans, were modeled at 1% and 2.5% annual urban growth, while SLR rates, based on the Intergovernmental Panel on Climate Change’s A1B mean and maximum scenarios, were modeled at 52 cm and 82 cm, respectively. SLR most greatly affected the shrub habitat with predicted losses of 35–43%. Salt marsh and tidal forest also were predicted to lose considerable area to SLR (20–45 and 23–35%, respectively), whereas oak and pine forests had lesser impact from SLR, 18–22% and 11–15%, respectively. Urban development resulted in losses of considerable pine (48–49%) and oak (53–55%) habitat with lesser loss of shrub habitat (21–24%). Under maximum SLR and urban growth, shrub habitat may lose up to 59–64% compared to as much as 62–65% pine forest and 74–75% oak forest. Conservation efforts should focus on protection of shrub habitat because of its small area relative to other terrestrial habitats and use by Painted Buntings (Passerina ciris), a Partners In Flight (PIF) extremely high priority species. Tidal forests also deserve protection because they are a likely refuge for forest species, such as Northern Parula and Acadian Flycatcher, with the decline of oak and pine forests due to urban development.     

Dental fluorosis—a case study from Nawa tehsil in Nagaur district,Rajasthan (India)

A study was carried out in Nawa tehsil of Nagaur district to assess the prevalence of dental fluorosis and its crippling effect due to ingestion and prolonged exposure of fluoride over a long period of time. During the survey of the study area, high concentration of fluoride (14.62 ppm) has been recorded. The presence of fluoride in quantities in excess of limits is a serious matter of concern from a public health point of view. Due to higher fluoride level in groundwater, several cases of dental fluorosis have appeared at alarming rate in the study area. The children’s teeth are damaged and are characterized by black and brown stains as well as cracking and pitting of the teeth have been observed. In the study area, 93.12% population suffered from dental fluorosis, and it was more prevalent in men (94.90%) than in women (90.00%). Dental fluorosis was also examined according to different grades. Out of the total 72 afflicted, in the 4–16-year age group, 41.46% were suffering from Grade I, Grade II was more prevalent in 33.85% of the 17–28-year age group and similarly Grade II was more prevalent in 39.13% of the 29–40-year age group. In the age group of above 40 years, grade III and grade IV were more prevalent. Thus, in the higher age group, the prevalence and severity of fluorosis is almost certainly due to longer exposure to fluoride. The major risk factor consistently identified for dental fluorosis was the consumption of fluoridated drinks and fluoride supplements. Ingestion of calcium, vitamin D and vitamin C is effective in protection from fluoride toxicity to certain extent.     

The frequency-dependent effect of extremely low-frequency electromagnetic field and mechanical vibration at infrasound frequency on the growth, division and motility of Escherichia coli K-12

The aim of this work was to investigate the frequency-dependent effects of extremely low-frequency electromagnetic field (ELF-EMF) and mechanical vibration at infrasound frequency (MV at IS frequency or MV) on growth and development of Escherichia coli K-12, by using classical microbiological (counting colony forming units), isotopic, spectrophotometric and electronmicroscopic methods. The frequency-dependent effects of MV and ELF-EMF were shown that they could either stimulate or inhibit the growth and the division of microbes depending on the periods following exposure. However, the mechanism through which the MV and ELF-EMF effects affect the bacteria cell is not clear yet. It was suggested that the aqua medium could serve a target through which the biological effect of MV and ELF-EMF on microbes could be realized. To check this hypothesis, the frequency-dependent effects (2, 4, 6, 8, 10 Hz) of both MV and ELF-EMF on the bacterial growth, division and their motility in cases of exposure, the preliminary treated microbes-free medium and microbes containing medium were studied. Both MV and ELF-EMF effect on microbes have frequency and post-exposure period duration-dependent characters. The [ ³ H]-thymidine involving experiments shown that EMF at 4 Hz exposure has pronounced stimulation effect on cell proliferation while 4 Hz MV has inhibition effect. But at 8–10 Hz, the both EMF and MV have inhibitory effects on cell proliferation. It is suggested that 4 and 8 Hz EMF have different biological effects on microbes.     

Deforestation Projections for Carbon-Rich Peat Swamp Forests of Central Kalimantan,Indonesia

We evaluated three spatially explicit land use and cover change (LUCC) models to project deforestation from 2005–2020 in the carbon-rich peat swamp forests (PSF) of Central Kalimantan, Indonesia. Such models are increasingly used to evaluate the impact of deforestation on carbon fluxes between the biosphere and the atmosphere. We considered both business-as-usual (BAU) and a forest protection scenario to evaluate each model’s accuracy, sensitivity, and total projected deforestation and landscape-level fragmentation patterns. The three models, Dinamica EGO (DE), GEOMOD and the Land Change Modeler (LCM), projected similar total deforestation amounts by 2020 with a mean of 1.01 million ha (Mha) and standard deviation of 0.17 Mha. The inclusion of a 0.54 Mha strict protected area in the LCM simulations reduced projected loss to 0.77 Mha over 15 years. Calibrated parameterizations of the models using nearly identical input drivers produced very different landscape properties, as measured by the number of forest patches, mean patch area, contagion, and Euclidean nearest neighbor determined using Fragstats software. The average BAU outputs of the models suggests that Central Kalimantan may lose slightly less than half (45.1%) of its 2005 PSF by 2020 if measures are not taken to reduce deforestation there. The relatively small reduction of 0.24 Mha in deforestation found in the 0.54 Mha protection scenario suggests that these models can identify potential leakage effects in which deforestation is forced to occur elsewhere in response to a policy intervention.     

Enrichment of vermicomposts prepared from cow dung spiked solid textile mill sludge using nitrogen fixing and phosphate solubilizing bacteria

Textile mill waste can be vermicomposted if it is mixed in the range of 20–30% with cow dung. This article reports the effect of inoculation, of nitrogen fixing Azotobacter chroococcum strain; Azospirillum brasilense strain and phosphate solubilizing Pseudomonas maltophila, on nitrogen and phosphorus content of vermicomposts prepared from cow dung (CD) and cow dung spiked textile mill sludge (CD + STMS). The CD vermicompost was more supportive to the growth and multiplication of all the three bacteria than CD + STMS vermicompost. In Azotobacter chroococcum treated vermicomposts maximum nitrogen content was recorded between 45 and 60 days [CD␣vermicompost (25.9 ± 0.45 g kg⁻¹) and CD + STMS vermicompost (20.6 ± 0.62 g kg⁻¹)] followed by Azospirillum brasilense inoculation [CD vermicompost (19.4 ± 0.60 g kg⁻¹) and CD + STMS vermicompost (18.6 ± 0.17 g kg⁻¹)]. Phosphorus content in Pseudomonas maltophila inoculated CD vermicompost was 20.8 ± 0.20 g kg⁻¹ and CD + STMS vermicompost was 13.4 ± 0.45 g kg⁻¹ after 75th day of inoculation.     

Preliminary assessment of indoor industrial noise pollution in Kuwait

Sound is considered as a pollutant when it exceeds undesirable limits for the recipient. One of the significant environmental problems associated with industries is noise pollution generated by machinery. The main objectives of this study were to measure noise levels generated by machinery that the workers were exposed to at five industrial facilities in the State of Kuwait. Also, to assess if these levels were within acceptable standards, for Kuwait lacks environmental standards for such a pollutant. To achieve the objectives of the study two food manufacturing companies, a cement-brick making plant, a furniture factory and a car washing facility were selected for the purpose of the research.The study showed that workers operating machinery at the five facilities were exposed to high noise levels without any kind of ear protection. Noise levels recorded during the study were very high and exceeded the British Noise at Work Regulations of 1989. In Kuwait there are no regulations to abate noise in the working environment and workers are not required to wear ear protective muffs. The results of the study indicate that, the concerned environmental and health organisations in Kuwait should be compelled to establish noise level standards and controls to safeguard the health of workers and the public at large.     

Dynamics of Plains Cottonwood (<Emphasis Type="Italic">Populus deltoides</Emphasis>) Forests and Historical Landscape Change along Unchannelized Segments of the Missouri River,USA

Construction of six large dams and reservoirs on the Missouri River over the last 50–75 years has resulted in major landscape changes and alterations in flow patterns, with implications for riparian forests dominated by plains cottonwood (Populus deltoides). We quantified changes in land cover from 1892–1950s and the 1950s–2006 and the current extent and age structure of cottonwood forests on seven segments (two reservoir and five remnant floodplain) comprising 1127 km (53 %) of the unchannelized upper two-thirds of the Missouri River. Riparian forest area declined by 49 %; grassland 61 %; shrubland 52 %; and sandbar habitat 96 %; while agricultural cropland increased six-fold and river/reservoir surface area doubled from 1892 to 2006. Net rates of erosion and accretion declined between the 1892–1950s and 1950s–2006 periods. Accretion exceeded erosion on remnant floodplain segments, resulting in declines in active channel width, particularly in 1950s–2006. Across all study segments in 2006, most cottonwood stands (67 %) were >50 years old, 22 % were 25–50 years old, and only 10 % were <25 years old. Among stands <50 years old, the higher proportion of 25–50 year old stands represents recruitment that accompanied initial post-dam channel narrowing; while declines in sandbar and shrubland area and the low proportion of stands <25 years old suggest declines in geomorphic dynamism and limited recruitment under recent river management. Future conservation and restoration efforts should focus both on limiting further loss of remnant cottonwood stands and developing approaches to restore river dynamics and cottonwood recruitment processes.     

Determinants of noise annoyance in teachers from schools with different classroom reverberation times

A high proportion of school teachers report that they are disturbed by noise during teaching. The aim of the study was therefore to identify determinants of self-reported noise exposure and disturbance attributed to noise among secondary school teachers (n = 419) in 10 schools in Copenhagen, Denmark. The schools were selected to show contrasts in classroom reverberation times (RT), and were classified as “Short RT” (3 schools, mean RT 0.41–0.45 s), “Medium RT” (3 schools, mean RT 0.51–0.55 s) and “Long RT” (4 schools, mean RT 0.62–0.73 s). Significant determinants of self-reported noise exposure were a high number of children in the class, young age of the children, and low teacher seniority. “Long RT” classification was of borderline significance. Significant determinants of disturbance attributed to noise from children in the class were teacher seniority and “Long RT” acoustic classification of the school. The associations between work characteristics and noise disturbance measures were attenuated by low self-rated work capacity, suggesting that the consequences of noise and poor acoustics may not be limited to disturbance attributed to noise, but may have a wide negative impact on the perceived working environment.     

Evaluation of aquifer vulnerability and the protective capacity in some oil producing communities of western Niger Delta

Oil spills have become a major environmental hazard constituting serious social problems in Nigeria, especially in the oil producing communities. The spills contaminate the aquifer if the subsurface layers are not protected. Geoelectric technique of geophysical investigation has been used to evaluate the protective capacity of six oil producing communities: Oleh, Olomoro, Uzere, Afiesere, Ekakpamre and Uvwiamuge in the western Niger Delta. A total of 139 vertical electrical sounding (VES) using the Schlumberger electrode configuration were occupied in these communities. The longitudinal conductance maps delineated areas with poor (<0.1 mho), weak (0.1–0.19 mho), moderate (0.2–0.69 mho) and good protective capacity (0.7–4.9 mho). The study has shown that the protective capacity of most parts of the communities studied is poor with Uvwiamuge and Ekakpamre communities not protected hence the aquifer in these oil producing communities are vulnerable to contamination by hydrocarbon in the event of pollution. Hence proper environmental protection measures have been suggested to safeguard the aquifer from pollution by hydrocarbon in the event of spillage.     

Effect of stocking density and food quality on the growth and fecundity of an epigeic earthworm (<Emphasis Type="Italic">Eisenia fetida</Emphasis>) during vermicomposting

Physico-chemical characteristics of the feed and optimum worm density are important parameters for the efficient working of a vermicomposting system. Overcrowding of worms can affect the efficiency of a vermicomposting system even if all other parameters have been optimized. This article reports the effect of stocking density and feed quality on the growth and fecundity of Eisenia fetida under laboratory conditions. The feed mixtures contained cow dung and textile mill wastewater sludge in different ratios. Three feed mixtures and five stocking rates (1, 2, 4, 8, and 12) were tested for 12 weeks. The results showed that E. fetida growth rate was faster at higher stocking densities; however, biomass gain per worm was faster at lower stocking densities. Sexual maturity was attained earlier at higher stocking densities. Growth rate was highest in 100% cow dung at all the stocking densities when compared to textile mill wastewater sludge containing feed mixtures. A worm population of 27–53 worms per kg of feed was found to be the most favorable stocking density.     

Managing Water to Protect Fish: A Review of California’s Environmental Water Account, 2001–2005

The Sacramento-San Joaquin Delta, the landward reach of the San Francisco Estuary, provides habitat for threatened delta smelt, endangered winter-run Chinook salmon, and other species of concern. It is also the location of huge freshwater diversion facilities that entrain large numbers of fish. Reducing the entrainment of listed fishes into these facilities has required curtailment of pumping, reducing the reliability of water deliveries. We reviewed the first 5 years (2001–2005) of the Environmental Water Account (EWA), a program instituted to resolve conflicts between protecting listed fishes and providing a reliable water supply. The EWA provided fishery agencies with control over 0.2–0.4 km³ of water to be used for fish protection at no cost to users of exported water, and fish agencies guaranteed no disruption of water supply for fish protection. The EWA was successful in reducing uncertainty in water supply; however, its contribution to the recovery of listed fishes was unclear. We estimated the effectiveness of the EWA to be modest, increasing the survival of winter-run Chinook salmon by 0–6% (dependent on prescreen mortality), adult delta smelt by 0–1%, and juvenile delta smelt by 2–4%. Allocating EWA water for a single life stage of one species could provide larger gains in survival. An optimally allocated EWA of equal size to the median of the first 5 years could increase abundance of juvenile delta smelt up to 7% in the springs of dry years. If the EWA is to become a long-term program, estimates of efficacy should be refined. If the program is to be held accountable for quantitative increases in fish populations, it will be necessary to integrate scientific, possibly experimental, approaches.     

Carbon Storage in Soil Size Fractions Under Two Cacao Agroforestry Systems in Bahia, Brazil

Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao (Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 μm, 250–53 μm, and <53 μm)—corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions—and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.     

Identifying Urban Features from LiDAR for a High‐Resolution Urban Hydrologic Model

Light Detection and Ranging (LiDAR), is relatively inexpensive, provides high spatial resolution sampling at great accuracy, and can be used to generate surface terrain and land cover datasets for urban areas. These datasets are used to develop high‐resolution hydrologic models necessary to resolve complex drainage networks in urban areas. This work develops a five‐step algorithm to generate indicator fields for tree canopies, buildings, and artificial structures using Geographic Resources Analysis Support System (GRASS‐GIS), and a common computing language, Matrix Laboratory. The 54 km² study area in Parker, Colorado consists of twenty‐four 1,500 × 1,500 m LiDAR subsets at 1 m resolution with varying degrees of urbanization. The algorithm correctly identifies 96% of the artificial structures within the study area; however, application success is dependent upon urban extent. Urban land use fractions below 0.2 experienced an increase in falsely identified building locations. ParFlow, a three‐dimensional, grid‐based hydrological model, uses these building and artificial structure indicator fields and digital elevation model for a hydrologic simulation. The simulation successfully develops the complex drainage network and simulates overland flow on the impervious surfaces (i.e., along the gutters and off rooftops) made possible through this spatial analysis process.     

C and N Content in Density Fractions of Whole Soil and Soil Size Fraction Under Cacao Agroforestry Systems and Natural Forest in Bahia,Brazil

Agroforestry systems (AFSs) have an important role in capturing above and below ground soil carbon and play a dominant role in mitigation of atmospheric CO₂. Attempts has been made here to identify soil organic matter fractions in the cacao-AFSs that have different susceptibility to microbial decomposition and further represent the basis of understanding soil C dynamics. The objective of this study was to characterize the organic matter density fractions and soil size fractions in soils of two types of cacao agroforestry systems and to compare with an adjacent natural forest in Bahia, Brazil. The land-use systems studied were: (1) a 30-year-old stand of natural forest with cacao (cacao cabruca), (2) a 30-year-old stand of cacao with Erythrina glauca as shade trees (cacao + erythrina), and (3) an adjacent natural forest without cacao. Soil samples were collected from 0-10 cm depth layer in reddish-yellow Oxisols. Soil samples was separated by wet sieving into five fraction-size classes (>2000 μm, 1000–2000 μm, 250–1000 μm, 53–250 μm, and <53 μm). C and N accumulated in to the light (free- and intra-aggregate density fractions) and heavy fractions of whole soil and soil size fraction were determined. Soil size fraction obtained in cacao AFS soils consisted mainly (65 %) of mega-aggregates (>2000 μm) mixed with macroaggregates (32–34%), and microaggregates (1–1.3%). Soil organic carbon (SOC) and total N content increased with increasing soil size fraction in all land-use systems. Organic C-to-total N ratio was higher in the macroaggregate than in the microaggregate. In general, in natural forest and cacao cabruca the contribution of C and N in the light and heavy fractions was similar. However, in cacao + erythrina the heavy fraction was the most common and contributed 67% of C and 63% of N. Finding of this study shows that the majority of C and N in all three systems studied are found in macroaggregates, particularly in the 250–1000 μm size aggregate class. The heavy fraction was the most common organic matter fraction in these soils. Thus, in mature cacao AFS on highly weathered soils the main mechanisms of C stabilization could be the physical protection within macroaggregate structures thereby minimizing the impact of conversion of forest to cacao AFS.     

50 Hz alternating extremely low frequency magnetic fields affect excitability,firing and action potential shape through interaction with ionic channels in snail neurones

In spite of growing concern about the influence of magnetic fields on biological systems, the interaction between extremely low frequency magnetic field (ELF magnetic fields) and biological structures at the cellular level remains obscure. The aim of this study was to investigate if 50 Hz magnetic fields could have an effect on the neuronal excitability and firing responses. Under Current-Clamp condition, exposure to 50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities resulted in an increase in the peak amplitude of action potential and after hyperpolaization potential in a time dependent manner. Both magnetic field intensities decreased also the firing frequency and the duration of action potential. Taken together, these data suggest that 50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities may change the electrophysiological behavior of neuronal cells and underlying ion channel currents.     

Investigating efficiency of <Emphasis Type="Italic">Lampito mauritii</Emphasis> (Kinberg) and <Emphasis Type="Italic">Perionyx ceylanensis</Emphasis> Michaelsen for vermicomposting of different types of organic substrates

The vermicomposting ability of Lampito mauritii (Kinberg) and Perionyx ceylanensis Michaelsen was evaluated by using three different types of organic substrates such as leaf litter of Polyalthia longifolia, Pennisetum typhoides cobs (pearl millet) and a weed, Rottboellia exaltata (whole plant except the roots) in combination with cowdung (1:1). Vermicomposting studies (120 days) conducted to optimize the number of worms required for efficient conversion based on the reduction of C/N ratio, percentage decomposition of organic substrates, total number and biomass of earthworms recovered from the vermibed substrates clearly showed that vermibeds with 4 kg of organic materials can hold about 60–80 L. mauritii and about 90–120 P. ceylanensis for efficient decomposition. The percentage decomposition of each organic substrate treated with different numbers of L. mauritii (20, 40, 60, 80 and 100 earthworms) and P. ceylanensis (30, 60, 90, 120 and 150) showed significant difference (P < 0.001) between numbers of worms introduced per vermibed but the difference between substrates was not significant within the treatments. Vermicomposting resulted in significant increase in electrical conductivity (28.54–49.82%), total nitrogen (43.96–90.83%), total phosphorus (27.42–68.10%) and total potassium (27.42–113.18%), whereas decrease in organic carbon (35.05–49.74%), C/N ratio (55.48–73.18%) and C/P ratio (50.46–66.90%) in different vermibeds introduced with L. mauritii and P. ceylanensis. Both the earthworm species can be used for vermicomposting different organic substrates; however, duration of vermicomposting with P. ceylanensis is not as much of L. mauritii. The use of L. mauritii for vermicomposting of other substrates has been well established by other workers also but standardization of P. ceylanensis, a locally available species, for vermicomposting of different organic substrates is a new finding and the species could be useful for vermiconversion of organic substrates under local conditions.