Population dynamics and changes in the population structure of a polymorphic colony of northern mole voles

Long-term (1985–1999) stationary observations on a polymorphic population of northern mole voles (Ellobius talpinus Pall.) in Kurgan oblast, Russia, using a mark-recapture method yielded original data on the population dynamics and population structure of a polymorphic colony consisting of animals of three color morphs (black, brown, and intermediate or transitional). The period when the northern mole vole population dynamics was studied (15 years) consisted of five distinct three-year population phases: depression, growth, peak (stabilization), decline to depression, and the next growth phase. It was shown that the population dynamics and changes in the population structure of northern mole voles in the Kurtamysh colony are cyclic.     

Spatial assessment of climate change effects on crop suitability for major plantation crops in Sri Lanka

Climate change is the main global challenge of this century; it is therefore imperative to identify its effects on agriculture in developing countries. This research makes spatial assessment of climate change effect on major plantation crops in Sri Lanka, with emphasis on crop suitability of tea, rubber, and coconut. Geo-referenced maps of spatial and temporal changes in crop suitability and production potentials are generated and compared. Data pertaining to six agro-ecological zones under the study area are analyzed for a period of 1980–2007. Crop suitability maps are generated amalgamating yield maps and climatic factors maps using AHP in multi-criteria analysis under two time frames of 1980–1992 and 1993–2007. Percent change in crop suitability and crop yield classes is calculated based on five crop suitability and five crop yield classes during two time frames. Dynamics of climatic parameters and crop yield are recognized using geo-referenced maps. The suitability maps of the two time frames are compared to identify the changes with each crop in conjunction with changes in the prevailing climate and yield. Geographic shift of suitability, yield, and climate classes are examined. Net gain or loss in crop production is quantified. Long-term annual rainfall significantly decreased in mid-country wet zone, whereas the mean temperature of the study area increased by 1.4°C. Results clearly showed that the climate and yield can be meaningfully related to the crop suitability and management.     

Estimation of the nutrient inputs into river systems – experiences from German rivers

The nutrient discharges from point and diffuse sources in more than 200 German river basins were estimated for the periods 1983–1987 and 1993–1997 employing the MONERIS model. This model distinguishes between six diffuse pathways and point source emissions from waste water treatment plants and direct industrial discharges. It was estimated that the total nitrogen input into the German river systems amounts to about 819,000 t N year^–1 in the period 1993 to 1997. These emissions have decreased since the mid-eighties by about 266,000 t N year^–1, mainly caused by the reduction of point discharges. For phosphorus the emissions have been reduced by 56,290 t P year^–1 and amount to 37,250 t P year^–1 in the period 1993–1997. Based on emission data a retention module estimates riverine nutrient loads. The comparison of the model output with the observed loads shows a deviation as low as 30% and 50% for nitrogen and phosphorus, respectively. The regional resolution of the model indicates the relative importance of different pathways for phosphorus and nitrogen input into river systems. Electronic Publication     

A forecast analysis on world population and urbanization process

The continuous growth of world population and the intensification of urbanization process create a challenge to environment quality and sustainable development around the world. In this paper I tried to conduct a forecast analysis of near-future urbanization related population growth worldwide, based on recent demographic trends. Such an analysis can provide important insights into the prospects for changes in the size and composition of world population and in urbanization process. Optimal polynomial functions were used to fit historical trajectories of population dynamics, and the detailed forecasts of the population mainly over the period 2010–2030 were conducted and analyzed. If the past pattern continues, world total population would increase to 7.94–8.33 billion in 2030 and the annual growth is expected to continually decline in the forecast period. Global total population would stop increasing during the period 2050–2060 and would not exceed 9.5 billion in the future. The total population of Africa, Asia, Oceania, South America, North & Central America would separately increase to 1.35–1.41, 4.86–5.65, 0.04–0.05, 0.44–0.45, and 0.71–0.72 billion in 2030. Europe’s total population is forecast to decline to 0.64–0.67 billion in 2030. World’s rural population is expected to grow to the maximum during the period 2015–2020 and would greatly decline after that period. Global rural population would reach 3.12–3.41 billion in 2030. Rural population in Asia and Africa is estimated to increase and achieve the maximum around 2025 and decline thereafter. For other regions, the rural population would continually decline in the forecast period. Urban population in the world would continually grow and reach 4.72–5.00 billion in 2030, an increase of 48.6–57.8%. However the annual growth of urban population is expected to increase to the maximum (6.86 million/year) during the period 2020–2025 and then decline in the following years. Urban population is projected to continually grow in all regions excepting Europe. Europe’s urban population is expected to decline in the period 2010–2030. Urbanization process worldwide, represented by the ratio urban population versus total population (RUT) and the ratio rural population versus urban population, is expected to continue during the period 2010–2030. The RUT of the world is projected to reach 0.5 before 2010 and would continue to increase in the forecast period. Global RUT is estimated to reach 0.56 in 2030. However, the regional patterns of urbanization process would be diverse. Europe’s RUT is estimated to continually decline in the forecast period and reach 0.68 in 2030. The RUT for Africa and Caribbean would continually increase before 2030, while the RUTs for Asia and South America are estimated to achieve their maximums around 2025 and decline in the following years. Oceania and North & Central America would thoroughly realize urbanization (≈1) during the periods 2020–2025 and 2025–2030. The expansion of world population and urbanization will continually exert a stronger stress to environment quality and sustainable development in a near future. However we may expect this situation would start to change from mid-21st century after total population has achieved its maximum. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.     

Impacts of climate change on lakes and reservoirs dynamics and restoration policies

Meteorological-driven processes exert large and diverse impacts on lakes and their water quality; these impacts can be hydrologic, thermal, hydraulic, chemical, biochemical, or ecological. The impact of climate change on Lake Tahoe (California–Nevada) was investigated here as a case study of climate change effects on the physical processes occurring within lakes. The already published trends of meteorological variables were used to assess the effects of global warming on Lake Tahoe dynamics. Records from the period 1969–2002 show that Lake Tahoe has became warmer and more stable. A series of simulation years into the future (i.e., 2000–2040) was established using flows, loads, and meteorology data sets for the period 1994–2004. Results of 40-year simulations show that the lake continues to become warmer and more stable, and mixing is reduced. Possible changes in water quality because of global warming are discussed through inference, although these are not specifically simulated. Many existing problems may be exacerbated due to climate change, yet extreme uncertainty depends on the rate and magnitude of climate change. Therefore, shifts in water quality and quantity due to climate change should be integrated into contemporary planning and management in an adaptive manner, and the research and development of impact assessment methodology should focus on approaches that can handle extreme uncertainty. The general alternatives for lake management due to climate change are discussed. Depending on the specific case, further intensive research is suggested to restore lake water quality.     

Detecting spatiotemporal change of land use and landscape pattern in a coastal gulf region,southeast of China

Geographic information system (GIS), remote sensing (RS), gradient analysis, and landscape pattern metrics were coupled to quantitatively characterize the spatiotemporal change of land use and landscape pattern over the period 1988–2007 in a coastal gulf region, southeast China. The results obtained show an increase in cropland, buildup land, and aquiculture area and decrease in orchard, woodland, and beach area during 1988–2007. Landscape fragmented processes were strengthened and landscape pattern structure became more complicated in the last two decades in Luoyuan gulf region. The dynamics intensity of landscape pattern is stronger during 2002–2007 than that during 1988–2002. Spatial difference of urban–rural landscape pattern can be detected distinctively in two transects in terms of landscape metrics. Urbanization processes and the policy developed to transfer seawater into buildup land are two driving forces leading to the spatiotemporal change of landscape pattern in Luoyuan gulf region in the last two decades.     

Soil organic carbon dynamics of croplands in European Russia: estimates from the “model of humus balance”

The Model of Humus Balance was used to estimate the influence of climate effects and changing agricultural practices on carbon (C) levels in soddy–podzolic soils in the Russian Federation for the years 2000–2050. The model was linked with a spatial database containing soil, climate and farming management layers for identification of spatial change of C sequestration potential. Analysis of relationships between C, soil texture and climate indicated that compared with a business-as-usual scenario, adaptation measures could increase the number of polygons storing soil organic carbon (SOC) by 2010–2020. The rate of possible C loss is sensitive to the different climate scenarios, with a maximum potential for SOC accumulation expected in 2030–2040, thereafter decreasing to 2050. The effect is most pronounced for the arid part of the study area under the emission scenario with the highest rate of increase in atmospheric CO₂ concentration, supporting findings from the dynamic SOC model, RothC. C sequestration during the study period was permanent for clay and clay loam soils with a C content of more than 2%, suggesting that C sequestration should be focused on highly fertile, fine-textured soils. We also show that spatial heterogeneity of soil texture can be a source of uncertainty for estimates of SOC dynamics at the regional scale. Figures in color are available at     

Understanding deforestation in the southern Yucatán: insights from a sub-regional, multi-temporal analysis

The southern Yucatán has been identified as a deforestation hot spot. Land-change studies document the extent of forest loss at a regional scale, and case studies provide insights into the drivers of deforestation at the household level. Those studies have paid minimal attention to sub-regional analysis, especially to discrete land-management units above the household level. This analysis of upland forest change addresses the range of variation in deforestation among 96 ejidos (communal lands) and the Calakmul Biosphere Reserve, the two dominant land-tenure and land-management units in the region. Satellite imagery, census, and land-tenure data are used to establish the extent and location of deforestation patterns, and multivariate techniques are employed to identify biophysical and socioeconomic variables that explain such patterns. Results show that, for the 1984–1993 period, deforestation in the southern Yucatán was not as prevalent as implied by its hot spot designation. Three clusters of deforestation are identified. A logistic regression analysis establishes that size of forest holdings, population growth, and location in the precipitation gradient correlate with ejidos that experienced higher deforestation rates than the rest of the land-tenure units. For the 1993–2000 period, conservation programs and changes in the economic context of this “hollow frontier” contributed to reduce deforestation rates and extent. This analysis illustrates the spatio-temporal heterogeneity of much tropical forest change and caution that it should bring to simple formulations of modeling this change and prescribing policies to control it.     

Consequences of changed wetness on riverine nitrogen – human impact on retention vs. natural climatic variability

The HBV-N model was used for a scenario analysis of changes in nitrogen retention and transport caused by alterations of wetness due to land drainage, lowering of lakes, building of dams and climatic variability in a river basin in south-central Sweden (1885–1994). In general, dams were situated in locations more favourable for retention, compared to the lowered lakes. Rather modest conversions of water bodies only changed nitrogen transport by about 3%. The 180-times-larger increase of (mainly) tile-drained agricultural land had, according to simulations, increased the nitrogen transport by 17%, due to reduced retention. However, compared to human-induced alteration of the landscape N retention, the choice of 10-year periods of climatological data had the overriding effect on the calculated nitrogen transport. Weather-induced variations resulted in a 13% difference in nitrogen retention between various 10-year periods. When the model was driven by climatological data from the driest 10-year period (1905–1914), the estimated average annual load was only half of that obtained with climatological data from the wettest 10-year period (1975–1984). Electronic Publication     

Irregularity in frequency of mast seed years in <Emphasis Type="Italic">Quercus floribunda</Emphasis> a late successional species of Central Himalaya

The mid altitudinal oak, Quercus floribunda forms predominantly evergreen forest in Central Himalaya between 2000–2400 m. It is late successional, mature phase species that has limited regeneration on disturbance prone sites. This oak produces mast seed crops at an interval of 2–3 years. During masting in Q. floribunda the seed fall and germination is upto ten times greater than in normal years, emphasizing the importance of mast year crop in forest maintenance. However, no mast year in this species since the last nine years (1997–2005) is a matter of serious concern. The rise in the summer and winter temperature over a period of 15 years appear to have affected the frequency of masting in this oak. The importance of masting can be adjudged from the fact that 97% of the surviving seedlings m⁻² are of the mast year crop.     

Migration and reclamation in Northeast China in response to climatic disasters in North China over the past 300?years

Climatic disaster-induced migration and its effects on land exploitation of new settlements is a crucial topic that needs to be researched to better understand the impact of climate change and human adaptation. This paper focuses on the process and mechanism of migrant–reclamation in Northeast China in response to climatic disasters over the past 300 years. The research used comparative analysis of key interlinked factors in this response involving drought/flood events, population, cropland area, farmer revolts, administrations establishment, and land reclamation policies. It draws the following conclusions: (1) seven peaks of migrants–reclamation in Northeast China were evident, most likely when frequent climatic disasters happened in North China, such as the drought–flood in 1851–1859, drought in 1875–1877, and drought 1927–1929; (2) six instances of policy transformation adopted to cope with extreme climatic events, including distinctive examples like changing to a firm policy prohibiting migration in 1740 and a subsequent lifting of that prohibition in 1860; and (3) the fast expansion of the northern agricultural boundary since the middle of the nineteenth century in this area benefited from a climate change trend from a cold period into a warm period. Altogether, over the past 300 years, extreme climatic disasters in North China have deepened the contradiction between the limited land resources and the rapidly increasing population and have resulted in migration and reclamation in Northeast China. Climate, policy, and reclamation constructed an organic chain of response that dominated the land use/cover change process of Northeast China.     

Spatial identification by satellite imagery of the crop–fallow rotation cycle in northern Laos

In the mountainous regions of northern Laos, shifting cultivation, or slash-and-burn agriculture, is widely practiced. However, the crop–fallow rotation cycle is becoming shorter owing to forest conservation policies and population pressure, causing loss of productivity that deleteriously affects farmers’ livelihoods in the region. To investigate regional land use conditions, we have developed a method of identifying the crop–fallow rotation cycle from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper+ (ETM+) data. We assessed the impact of the identified cycle on plant production measured by Normalized Difference Vegetation Index (NDVI). The study site was an area in Luang Prabang Province. Using eight TM and ETM+ images acquired annually from 1995 to 2003, except for 1998, when cloud-free data were not collected, we classified land use in each year as crop or fallow by the presence of vegetation in the late dry season. Conformity with fallow age determined by field investigation was 69.1%. The cultivation frequency from 1995 to 2002 showed that 77,000 ha (17.3% of the study site) had not been used for cropping during the period, but 41,000 ha (9.2%) had been used every year. Of the study site, 129,000 ha (29.1%) was cultivated one or two times, 83,000 ha (18.7%) was three or four times, and 54,000 ha (12.2%) was five or six times. The NDVI of crops in November did not provide sufficient evidence to prove the assumption that a longer fallow period would result in better crop yields. Instead, the regeneration of fallow vegetation was evidenced by the higher NDVI values after longer fallow. More than 8 years would be needed to reach the same NDVI as forest. From the produced maps indicating fallow age and cultivation frequency, we found that areas with high potential for regeneration decreased as cultivation frequency increased. Areas near rivers were intensively used, and fallow length was accordingly short. Low-potential areas were found in the western basin of the Mekong River. This spatial information can be used to detect areas where biomass productivity is at high risk of deteriorating. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Comparative analysis of the population structure of social vole (Microtus socialis Pall., 1773, cricetidae, rodentia) in different areas of its range

A comparative analysis of the spatial-ethological structure of social vole (Microtus socialis Pall.) colonies was made on the basis of studies performed in Dagestan (1987–1991) and the southern Kalmyk Republic (1993–1998). Notwithstanding differences in environmental conditions and the extent and forms of anthropogenic impact, the population structure of the species proved to be similar and stable. Irrespective of population density, its core consists of family groups. Specific features of social behavior (aggressiveness toward unfamiliar animals) provide for the protection of home ranges and help to maintain a stable population structure.     

Energy futures and green chemistry: competing for carbon

Global energy demand is expected to increase from the current 400 ExaJ per year to as much as 700–1,000 ExaJ per year by the middle of this century. If fossil carbon resources continue to make up the bulk of the energy supply, not only will atmospheric carbon dioxide increase to levels not seen for the past 30–35 million years, but depleting fossil carbon resources will become increasingly less available for other purposes, particularly the production of chemicals on which society now depends. The chemical process industries are heavily dependent on the availability of low-price petroleum as a feedstock. Recent life-cycle analyses suggest that pursuing both strategies of renewable energy sources and renewable feedstocks (i.e. biomass) will be required to meet these competing demands. Reducing the global use of both energy and manufactured chemicals will be a challenge for sustainable development. Education of the next generation of chemists and chemical engineers will have to change significantly from its current emphasis on petrochemical-based manufacturing to include a much greater emphasis on renewable resources and bio-based processes.Brief accounts of this work were presented at the 7th International Symposium on Green Chemistry in China (Zhuhai, People’s Republic of China, May 2005) and at the Joint US–China Green Chemistry Workshop (Beijing, People’s Republic of China, May 2005; this workshop was supported by US National Science Foundation grant CHE-0522369).     

Optimum Supportable Global Population: Water Accounting and Dietary Considerations

In this paper we develop a novel, comprehensive method for estimating the global human carrying capacity in reference to food production factors and levels of food consumption. Other important interrelated dimensions of carrying capacity such as energy, non-renewable resources, and ecology are not considered here and offer opportunities for future work. Use of grain production (rain-fed/irrigated), animal product production (grazing/factory farm), diet pattern (grain/animal products), and a novel water accounting method (demand/supply) based on actual water consumption and not on withdrawal, help resolve uncertainties to find better estimates. Current Western European food consumption is used as a goal for the entire world. Then the carrying capacity lies in the range of 4.5–4.7 billion but requiring agricultural water use increase by 450–530% to 4725–5480 km³, the range based on different estimates of available water. The cost of trapping and conveying such water, will run 4.5–13.5 trillion over 50 years requiring an annual spending increase of 150–400%, straining the developing world where most of the population increase is expected. We reconfirm estimates in the literature using a dynamic model. ‘Corner scenarios’ with extreme optimistic assumptions were analyzed using the reasoning support software system GLOBESIGHT. With a hypothetical scenario with a mainly vegetarian diet (grazing only with 5% animal product), the carrying capacity can be as high as 14 billion. Ecological deterioration that surely accompanies such a population increase would negatively impact sustainable population. Using our approach the impact of ecological damage could be studied. Inter- and intra-regional inequities are other considerations that need to be studied.     

Soil carbon dynamics in a Mediterranean forest during the Kyoto Protocol commitment periods

The purpose of the present work is to asses the possibility of detecting changes in soil organic carbon (SOC) at the end of the 5-years of the first Commitment Period (CP) of the Kyoto Protocol of the United Nation’s Framework Convention on Climate Change (1 January, 2008–31 December, 2012), by both direct measurement and the use of an opportunely evaluated SOC model, CENTURY. The investigated soil is young, developed since 28 years on virtually C-free spoil banks and under the influence of two managed forest stands, one a mix of English oak (Quercus robur L.) and Italian alder (Alnus cordata Loisel.) and the other pure English oak. The SOC stock of either stand was monitored since the time the stands were planted in 1981, and it was used together with other parameters for the model evaluation, while the future projections for the end of the first (2012) and second (2017) CP were made according to two extreme IPCC climatic scenarios: A1F1, the most dramatic, and B2, among the less impacting. Direct SOC measurements performed at the beginning and at the end of a time frame equivalent to a commitment period (2004–2008) had not shown significant variations in either stands. Compared to the 2008 SOC stock, in both stands the model shows variations at the end of the first CP from 0.7 to 1.8 Mg C ha⁻¹ for the A1F1 scenario and from 0.3 to 1.7 Mg C ha⁻¹ for the B2. These variations are within the standard deviations of the C stocks measured in 2008. On the contrary, at the end of the second CP, the modelled SOC increments range from 2.5 to 3.6 Mg C ha⁻¹ (A1F1) or from 1.9 to 3.4 Mg C ha⁻¹ (B2), indicating the possibility to detect the SOC changes by direct measurement, since the values well agree with the minimum detectable variation estimated for both sites in 3.3–4.5 Mg C ha⁻¹. This work shows that SOC stock changes measured directly in the field can be minimal at the end of both CPs, and that CENTURY well simulates the SOC dynamics of the stands. The use of such a model, validated at long-term experimental sites, hence represents an effective tool for estimating future changes in SOC amounts in support of direct measurements when a short period of time, such as the CP, is considered.     

Mutagenicity of atmospheric air and snow cover in the city of Syktyvkar estimated by the somatic mutation test inTradescantia (Clone 02) stamen hairs

Genotoxicity of atmospheric air was studied in Syktyvkar for three years (1995–1997) using the test of somatic mutations inTradescantia (clone 02) stamen hairs. The data obtained indicate local air pollution in the city. The tested samples of snowmelt, where Ni⁺ and Zn²⁺ ions were the main pollutants, had a high teratogenic effect on stamen hairs. The somatic mutation rate similar to that in the control group was obtained in the experiment with only one sample, in which the total content of metal ions was the lowest.     

Using diatoms to assess the impacts of prehistoric, pre-industrial and modern land-use on Danish lakes

The impact of contemporary agriculture on Danish lakes is acknowledged to be extreme. In particular, high loading of nutrients from agricultural soils contributes to the eutrophic conditions found in many of Denmark’s lakes. Palaeolimnological studies have shown that human disturbance of the Danish landscape since the introduction of agriculture around 6,000 years ago has had a major impact on lake ecosystems. The European Union’s Water Framework Directive requires an evaluation of reference conditions for lakes, the conditions expected with only minimal human impact. Monitoring data and palaeolimnological studies of Danish lakes demonstrate that many of the most detrimental effects of eutrophication have been experienced in recent decades. A new study has suggested that the reference status for Danish lakes may be set to the status in ad 1850–1900, probably providing attainable, realistic restoration targets for many sites. The aims of this study were to explore the impacts of past and contemporary land-use on Danish lakes, and to consider how appropriate the use of 1850 as a date to define reference status is for these sites. Catchment land-cover data for ad 1800, taken from historical maps, and sedimentary diatom assemblages of the same age, from dated sediment cores, were used to assess the impact of pre-industrial land-use on 20 Danish lakes. Analysis of contemporary land-cover data and surface-sediment diatom assemblages for the 20 sites was also made. In-lake total phosphorus (TP) concentrations were estimated using the sedimentary diatom assemblages and an existing calibration dataset for Danish lakes. The percentage of the lake catchment that was agricultural land in ad 1800 explained 8.8% of the total variation in the diatom data. The land-cover variables ‘built-up areas’ and ‘plantations’, together explained 16.9% of the variation in the diatom data for the modern samples. Diatom-inferred TP concentrations were high for both ad 1800 (mean 112 μg TP L⁻¹) and the present (mean 122 μg TP L⁻¹), the latter estimates reflecting efforts in recent decades to reduce nutrient loading to Danish lakes following very high levels of nutrient enrichment post-1950. The data presented highlight the impact that human activities 200 years ago, particularly agriculture, had on Danish lake systems. The long cultural history and major anthropogenic disturbance of the Danish landscape mean that true reference conditions for lakes (or ‘baseline’ conditions, those found prior to human impacts) can be found only by considering century to millennial timescales.     

The narrow-skulled vole (<Emphasis Type="Italic">Microtus gregalis</Emphasis> Pall.) in the dynamics of zonal rodent communities of northern Eurasia

On the basis of abundant fossil and subfossil bone remains, the ecological and faunal role of the narrow-skulled vole in zonal rodent communities of northern Eurasia is analyzed over the period from the Late Pleistocene to the present time. Special attention is given to the correlated dynamics of relative abundance of Microtus gregalis and other rodent species in the course of transition from one zonal type to another and to specific features of this correlation in the southern, middle, and northern parts of the species range. It is shown that distinctive dimensional and morphotypic features of the two currently existing subspecies, Microtus gregalis major Ogn. and M. g. gregalis Pall., are the product of concordant development of the species and environmental conditions in the past 3000–4000 years (transition from the Holocene optimum to the present-day climate and state of the natural environment). Published in Russian in Ekologiya, 2007, Vol. 38, No. 2, pp. 117–123. The article was translated by the authors.     

Farming dynamics and social capital: A case study in the urban fringe of Mexico City

Urban development has important implications for farmland preservation and natural resource management in local peri-urban communities. Social science research on recent changes in rural landscape of mega-cities tends to be limited to case studies in Latin-American nations. This study analyses the socioecomic dynamics of farming land use and the interactions between multiple cultural variables and the environment. Fieldwork was carried out during the 2002–2003 period in rural livelihoods of the five high mountain towns of south Mexico City. Data obtained from participatory survey and ethnographic techniques were integrated to assess changes in rural landscape and resource management and how urbanization, deforestation and market oriented agricultural production result in different livelihoods within a similar urban fringe context. The dynamic of mixture of urban and rural landscapes is based on farm productivity and social capital factors. The study concludes that policy support for regional agricultural production systems through enhancing ecosystems services, environmental protection and economic development is needed for sustainable development of local communities. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue