The effects of gas flaring on crops in the Niger Delta,Nigeria

Flaring of associated gas from oil exploitation has several consequences on the environment. This study explores the spatial variability effects of gas flaring on the growth and development of cassava (Manihot esculenta), waterleaf (Talinum triangulare), and pepper (Piper spp.) crops commonly cultivated in the Niger Delta, Nigeria. Data was collected on soil and atmospheric temperature and moisture at a 20-m interval, starting at 40 m from the flare point to a distance of 140 m. Lengths and widths of crop leaves, height of crop plants and cassava yields were measured at the specified distances. The amino acid, ascorbic acid, starch, and sugar constituents of the cassava yields were determined. The results suggest that a spatial gradient exists in the effects of gas flares on crop development. Retardation in crop development manifests in decreased dimensions of leaf lengths and widths of cassava and pepper crops closer to the gas flare point. Statistical analysis also confirms that cassava yields are higher at locations further away from the flare point. In addition, the amount of starch and ascorbic acid in cassava decreased when the plant is grown closer to the gas flare. High temperatures around the gas flare appear to be the most likely cause of this retardation. The waterleaf crop, on the other hand, appears to thrive better around the gas flare point.     

DC resistivity and seismic refraction survey across the SE margin of Lake Ngami,NW Botswana

Seismic refraction survey and DC resistivity measurements were made across the margin of the Lake Ngami. The structure and stratigraphy at the lake were determined. High resolution aeromagnetic data showed a prominent anomaly coinciding with the Kunyere Fault. Estimated depths to magnetic sources are increasing towards the lake. Two velocity layers were mapped. The top layer (500 m/s) is thin outside the lake and thicker inside the lake. The underlying layer (3125 m/s) has undeterminable thickness. Resistivity sounding results inside the lake showed that the low velocity layer has four sub-units: dry hard clays; diatomaceous earth; soft clays interlayered with silts; and wet whitish clays interlayered with silts. Normal faults were mapped along the profile with a total displacement up to 50 m. The results of the study indicate that the formation of the Lake Ngami basin was structurally controlled and probably initiated by the tectonics of the Okavango Rift Zone.     

Geographical distribution of the Soviet-Jewish new immigrants in Israel

The State of Israel is facing now one of the most difficult absorption challenges it has ever had. About 250.000 Soviet-Jewish immigrants have arrived to the country since 1989 and another million are waiting in the Soviet Union for immigration. A direct absorption plan around an absorption basket of a few thousand dollar per family of three for the first year enables the immigrants to choose their place of habitation. They concentrate in big cities and veteran settlements along the coastal plain where employment possibilities are better. This trend is against the government's plans to direct them to peripheral regions. The current mass-immigration creates an unexpected change in the population and settlement pattern of Israel.     

Geography of alarm zoning in Israel

During the Gulf War Israel was divided into six alarm zones to enable the people to be released gradually from their shelters according to the rate of damage and danger which has been in the different regions. These zones were outlined superficially, neither according to basic geographical elements, nor to the ballistic behaviour of the Iraqi missiles. A modified division into ten alarm zones was announced in September 1992 following the blockade which the USA had laid on military aviation in southern Iraq. A different division of alarm zones, based on ballistic and geographical parameters is proposed should there be missile attacks on the country in the future.     

Industry in Israel's new development towns

Conclusions The industrialization of the development towns is one of the main factors in the creation of a modern productive economy in a new social environment. The proportion of Israel's large industrial plants that have been located in the developments town is much larger than the corresponding proportion of all the country's industries. The tendency to establish relatively large industries in the development towns will probably continue for a considerable time, and it will necessitate the chanelling of large government resources to the development regions.A more serious obstacle is the shortage of labour, and particularly of skilled labour. In contrast to the supply of capital, this difficulty cannot be solved by administrative decisions taken in accordance with an agreed economic policy. What is needed here is a revolution in vocational training, and a diversification in plant sizes, the smaller plants supplying services to the larger industries.Vocational education is one of the most important conditions for the success of the industrialization process in the development towns. Jews have no technological and industrial tradition, and when they established their state, they did not attach sufficient importance to the rapid training of a labour force that would be able to take its place in the new factories. In making up for this omission, it is important to avoid concentrating on the conservative and traditional trades, and attention should be paid to the needs of the newer and more sophisticated industries.     

Israel's map of inequality in spatial development

The objectives of the paper are to indicate, on a national and regional level, the areas of geographical inequality in Israel, which create economic and social gaps in the development of the country. Geographical inequality in this study has been analyzed through eleven different criteria, relevant to economic and social welfare situations, as: distance from the nearest big city, road accessibility, rate of population density, natural economic potential, spatial security, distance from the central plain and centers of economic activity, climatic index of discomfort, topography, oldness of the settlements in the surroundings, etc. Each element of inequality has been plotted on a map indicating its quantitative values,on the basis of square units, comprising 25 km² each. A weighting of all the squares according to qualitative criteria enabled to prepare a comprehensive and compilative map with isolines showing the different spatial and inequality degrees.The map which has been elaborated from the data shows districts and localities in a range of different spatial degrees of deprivation. The history of settlement in Israel since the end of the 19th century, the planning guidelines since the establishment of the State in 1948, and the main geographic features of the country are the reasons of regional disparities.     

Random walk, zonation and the food searching strategy of Terebralia palustris (Mollusca, Potamididae) in Kenya

Terebralia palustris is a common mud-whelk present at a particularly high density in all Indo-West Pacific mangroves. Young snails feed on nothing but mud while larger specimens are able to feed on fallen leaves too. In Kenya (Mida Creek) under the canopy, competition for mangrove leaves can be very high due to the high density of Sesarmidae crabs. On open exposed muddy platforms, no Sesarmidae occur but the leaf density is very low because the leaves are only randomly present as they are deposited and removed twice a day by the tide. However, the snail density is always very high, raising the question as to whether the snails use a special searching strategy to optimize their resource finding rather than a purely random movement. By analyzing the snails' movements on a uniform area at different levels and comparing them with simulated random paths, we could show that the snails' movements are not purely random. The distribution of different size classes of T. palustris in Mida Creek was known to be quite odd: the same simulation approach suggests that the zonation asymmetry could reasonably be due to the stochastic recruitment of juveniles in space and time and maintained by a substantial long-lasting spatial inertia.     

Paleolimnological features of a mega-lake phase in the Makgadikgadi Basin (Kalahari,Botswana) during Marine Isotope Stage 5 inferred from diatoms

The Makgadikgadi–Okavango–Zambezi basin (MOZB) is a structural depression in the south-western branch of the East African Rift System of the northern and middle Kalahari, central southern Africa. In the present day, the mainly dry subbasins of the MOZB are part of a long-lived lacustrine system that has likely existed since Early Pleistocene and from which an extant freshwater fish radiation emerged seeding all major river systems of southern Africa. During hydrologically favourable periods the subbasins were connected as a single mega-lake termed Lake Palaeo-Makgadikgadi. Previous geomorphological studies and OSL dates have provided evidence for repeated mega-lake periods since approximately 300 ka. The environmental and climatic implications of such large scale late Quaternary lake-level fluctuations are controversial, with the duration of mega-lake phases poorly constrained. Here, we present the first evidence for a Marine Isotope Stage (MIS) 5 mega-lake period (about 935–940 m a.s.l.) reconstructed from a diatom-rich, 30-cm-thick lacustrine sediment section, exposed close to a palaeo-shoreline of the Makgadikgadi Basin. Based upon the environmental setting and in comparison with sedimentation rates of other similar lake environments, we tentatively estimated that the highstand lasted approximately 1 ka during MIS 5d–b. The 30-cm section was sampled in 0.5-cm steps. Diatom species diversity ranges from 19 to 30 through the section. The dominant species are Pseudostaurosira brevistriata, Rhopalodia gibberula, Cyclotella meneghiniana and Epithemia sorex. The total of 60 sediment samples provide us with a record at decadal to bi-decadal resolution. Based on diatom assemblages and their oxygen isotope composition (δ¹⁸O) we infer an alkaline and mostly oligohaline lake with shallow water conditions prevailing in MIS 5, and is potentially analogous to a Heinrich event. The climate over southern Africa during MIS 5 has been considered very arid but the hydromorphological context of our sediment section indicates that we captured a mega-lake period providing evidence that short-term excursions to significantly higher humidity existed. A hydrologically more favourable environment during MIS 5 than formerly presumed is in line with the early human occupation of the Kalahari.