RUNOFF VOLUME ESTIMATION USING GIS TECHNIQUES1

ABSTRACT: Rainfall runoff of six watersheds was modeled via the Soil Conservation Service runoff curve number model in two ways: conventionally (manually) and via a geographic information system (GIS). Input data (elevation, soils, and landcover) were digital for the latter method. In contrast to previous studies, the GIS was ised for all phases of the modeling process, including watershed delineation and routing of runoff. A comparison between the two methods was consistent with results reported by others and indicates that the use of a GIS is an acceptable alternative to the conventional method for watersheds lacking relatively flat terrain. Given this limitation, the GIS method may prove advantageous over manual methods when study areas are large or numerous, runoff is modeled repetitively, alternative landcover scenarios are explored, or a digital database already exists for the study area.     

The psychological effects of false-positive results in prenatal screening for fetal abnormality: A prospective study

The purpose of the study was to describe the impact of false-positive results from initial maternal serum alpha-fetoprotein (MS-AFP) screening. The analyses compared two groups of women, those receiving a negative result (n = 346) and those receiving an initial positive result (n = 26), over four time points—prior to testing, immediately after testing, later in pregnancy, and in the post-partum period. Receiving an abnormal result was associated with high levels of anxiety which were reflected in increased worry about the baby's health and a more negative attitude towards the pregnancy and the baby. Women who had an initial abnormal result were offered a variety of further tests. Those women who went on to have amniocentesis were less worried about their baby's health in the third trimester and also less anxious post-partum than those who did not have amniocentesis. In view of the increasing number of screening tests available, it is necessary to establish whether and how these levels of distress can best be reduced.     

Developmental changes in the composition of myofibrillar proteins in the swimming muscles of Atlantic herring,Clupea harengus

Changes in myofibrillar protein composition during development have been investigated in the swimming muscles of the Atlantic herring Clupea harengus L. using a range of electrophoretic techniques. The main muscle-fibre type of larvae, and the fast- and slow-muscle fibres of adult fish were found to contain distinct isoforms of myosin heavy chain (MHC) and myosin light chain 2 (LC2). Larval LC2 was present as a minor component of adult fast-muscle myosin. In contrast, larval and adult fast-muscle myosin appeared to contain identical alkali light chains. Tropomyosin and troponin C were also identical in larval and in adult fast-muscle. All three muscle-fibre types contained unique isoforms of troponin T (TNT) and troponin I (TNI). Larval muscle had multiple isoforms of TNT, some of which may correspond to embryonic forms. It was concluded that although the main muscle-fibre type in larvae shares some myofibrillar proteins with adult fast muscle, it also contains characteristic isoforms of MHC, TNI, TNT and LC2 and therefore represents a distinct fibre type. The particular combination of myofibrillar proteins present at any developmental stage was found to be dependent on the rearing temperature. For example, a higher proportion of embryonic TNT isoforms were present at hatching in larvae reared at 5°C than at either 10 or 15°C. Over a period of 7 d, there was a gradual reduction in the number of TNT isoforms, but the pattern in 5°C larvae after 7 d still did not resemble that in 1 d-old larvae reared at 15°C.     

Temperature influences muscle differentiation and the relative timing of organogenesis in herring (Clupea harengus) larvae

Eggs from spring spawning stocks of herring (Clupea harengus L.) were fertilized and reared at either 5, 8 or 12°C in 1991 and 1992. The differentiation of myotomal muscle fibres was investigated in relation to the development of other organs and tissues using light and electron microscopy. The gut, notochord, eyes and haemocoel appeared at the same relative point in development between fertilization and hatching at all temperatures. In contrast, the formation of the spinal cord, pronephros, pectoral fin buds and muscle fibres was relatively retarded at 5°C compared with 8 and 12°C. Myogenesis in the presumptive inner muscle mass occurred after 12 to 16 d at 5°C, 7 to 10 d at 8°C and 3.5 to 6 d at 12°C. Myoblasts aligned in orderly rows running from myosept to myosept prior to fusion to form myotubes. Actin and myosin filaments were synthesised throughout the cytoplasm in associated with presumptive Z-lines at the periphery of myotubes and immature muscle fibres. Differentiation of the superficial and inner muscle fibres types of larvae occurred at around the same time. Following this initial period of myogenesis, the number of myotomal muscle fibres remained constant until after hatching, so that increases in muscle bulk in the late embryo were entirely due to fibre hypertrophy. At hatching, the number of superficial muscle fibres present in myotomes just posterior to the yolk-sac was significantly less at 5°C (108±12) than at either 8°C (132±10) or 12°C (140±10) (mean±SD, 12 fish/temperature). In contrast, there were around 280 inner muscle fibres/myotome, comprising 90% of the trunk cross-sectional area, at all three temperatures. Myofibrillargenesis occurred relatively slowly at low temperatures, so that the volume density of myofibrils in the inner muscle fibres of larvae at hatching was significantly less at 5°C (39.2±9.0) than at either 8°C (49.6±8.8) or 12°C (50.2±9.8) (mean ±SD, 20 fibres/temperature from total of 5 fish). Undifferentiated myoblasts remained at hatching to form a population of presumptive myosatellite cells. The number of presumptive myosatellite cells per mm² cross-sectional area of muscle fibre was more than two times higher at 8°C (1493±335) than at either 5°C (478±102) or 12°C (924±233) (mean±SD, 5 fish/temperature). The results suggest that temperature can influence the commitment of myoblasts to differentiation at a critical stage in embryogenesis, thereby providing a potential mechanism for influencing future growth characteristics. Correspondence to: I.A. Johnston at Gatty Marine Laboratory     

Cultivated cells from mid-trimester amniotic fluids. IV. Cell type identification via one and two-dimensional electrophoresis of clonal whole cell homogenates

Clones of cultivated amniotic fluid cells that have distinct morphologic and growth characteristics (F, AF and E-type) were examined by one-dimensional SDS polyacrylamide gel electrophoresis (SDS-PAGE) and by two-dimensional electrophoresis employing isoelectric focusing and SDS-PAGE (IEF-PAGE). No qualitative differences in band pattern were observed in SDS-PAGE between the various amniotic fluid cell types, but consistent quantitative differences in the ratios of four bands of presumed filamentous proteins provided good distinction between amniotic fluid cells and postnatal skin fibroblast-like cells. By adding separation on the basis of electrical charge to that of molecular size (IEF-PAGE), we observed reproducible qualitative differences in the protein spot patterns between F and both AF and E-type amniotic fluid cells. At least eight discrete proteins appear not to be synthesized by prenatal F-type cells in comparison with their isogenic AF and E counterparts under identical culture conditions. The two-dimensional electrophoretic patterns thus confirm that F and AF amniotic cells, in spite of their morphologic and growth kinetic similarities, are developmentally distinct cell types that retain their differentiated states in culture.     

Forest fires and environmental haze in Southeast Asia: using the 'stakeholder' approach to assign costs and responsibilities.

The 'seasonal haze' problem is one which afflicts large parts of Southeast Asia in years of drought. The major cause is forest, bush and field fires in the states of Kalimantan and Sumatra in Indonesia, and to a lesser extent in Sabah, Sarawak, and other parts of Malaysia. Almost all of these fires now seem preventable, since they are intentionally set to clear land for cultivation. Theoretically, the government authorities at central, provincial and local levels in these countries should be responsible for controlling activities in their territory. In practice, however, air pollution control through regulatory policies and practices is extraordinarily difficult to implement and maintain in a situation of this kind in developing countries, especially at a time of crippling economic setbacks. Moreover, the establishment of legal liability, through an international tribunal or otherwise, hardly seems a politically feasible course of action for the government of an affluent 'victim state' such as Singapore. Faith in the usual solutions--science, regulation, law and diplomacy--is weakened by one's sense of current realities. The purpose of this paper is to review the issues and suggested responses, the cost implications of each, the responsibilities as well as entitlements that might apply to the various stakeholders, and the special role of Singapore as an affluent 'victim state'. We also discuss the incentive mechanisms that would be needed to manage forest fires.     

Post-settlement energy reserves in <Emphasis Type="Italic">Panulirus cygnus</Emphasis>: experimental effects of starvation on survival and nutritional condition

Post-settlement survival success in rock (spiny) lobsters is likely to be influenced by the nutritional condition of the non-feeding pueruli at settlement. Consequently, we predict that survival shortly after settlement depends on food resources being replenished rapidly. In the present study the length of the starvation period on survival in post-puerulus juveniles of the western rock lobster Panulirus cygnus was investigated using laboratory experiments. All experimental pueruli were collected from Seven Mile Beach, Western Australia, using sandwich puerulus collectors. Total lipid, lipid class, fatty acid, total protein and total glycogen analyses were conducted on fed and starved post-puerulus juvenile lobsters, from moult into the first juvenile stage to 30 days post-moult. From a total of 165 samples used in this study, 15 post-puerulus juveniles were sampled initially and five post-puerulus juveniles sampled every 5 days thereafter for biochemical analysis. Post-puerulus juveniles survived up to 34 days of starvation. The maximal starvation time for post-puerulus juveniles from which recovery was observed is estimated to be in excess of 22 days. Lipids, in particular phospholipids, are shown to be the most important source of energy catabolised during the starvation period, with greater than 62% reduction in total lipid at day 30. Proteins were also catabolised during starvation, but to a much lesser extent than lipid, decreasing by 34% in total content at day 25. Carbohydrates were present always as a minor constituent, however their content did not change significantly during starvation. Our results suggest that the pueruli collected in December 2004 were generally in sufficiently good condition to survive further starvation after settlement; nutritional levels of the post-puerulus juveniles were enhanced compared to those observed in previous studies. We suggest that the high levels of energy reserves in rock lobster post-pueruli may provide an adaptive advantage to aid the transition from pelagic to benthic living by minimising stress and the consequences of failing to locate immediately suitable food resources.     

Integrated Measures of Anthropogenic Stress in the U.S. Great Lakes Basin

Integrated, quantitative expressions of anthropogenic stress over large geographic regions can be valuable tools in environmental research and management. Despite the fundamental appeal of a regional approach, development of regional stress measures remains one of the most important current challenges in environmental science. Using publicly available, pre-existing spatial datasets, we developed a geographic information system database of 86 variables related to five classes of anthropogenic stress in the U.S. Great Lakes basin: agriculture, atmospheric deposition, human population, land cover, and point source pollution. The original variables were quantified by a variety of data types over a broad range of spatial and classification resolutions. We summarized the original data for 762 watershed-based units that comprise the U.S. portion of the basin and then used principal components analysis to develop overall stress measures within each stress category. We developed a cumulative stress index by combining the first principal component from each of the five stress categories. Maps of the stress measures illustrate strong spatial patterns across the basin, with the greatest amount of stress occurring on the western shore of Lake Michigan, southwest Lake Erie, and southeastern Lake Ontario. We found strong relationships between the stress measures and characteristics of bird communities, fish communities, and water chemistry measurements from the coastal region. The stress measures are taken to represent the major threats to coastal ecosystems in the U.S. Great Lakes. Such regional-scale efforts are critical for understanding relationships between human disturbance and ecosystem response, and can be used to guide environmental decision-making at both regional and local scales.