Oxygen isotopic variations of snowfall from winter storms in the central Sierra Nevada; Relation to ice growth microphysics and mesoscale structure

Observations have been made of the ice-crystal morphology of snow which fell at two sampling sites during a warm front followed by a cold front in the Sierra Nevada of the western United States. The snow sampling and ice crystal observations were conducted at Kingvale (KV) and Hobart Mills (HM), California, which are located at almost identical elevations on the upwind and down wind sides of the Sierra Nevada crest, respectively.These observations and several mesoscale features of one of the storms, have been used to study the substantial changes which occurred in the stable oxygen isotopic composition (δ¹⁸O) of the precipitation at the two sites.At the beginning of the period of observation, a low level warm front lay across the region and its elevation lowered with time from 2.5 km to 1.7 km. This decrease of the frontal surface height was accompanied by a steady increase in the δ¹⁸O values.In the pre-cold frontal passage time periods, the δ¹⁸O values at the upwind site signified warmer origin ice crystal morphology than the downwind site. This is explained by orographic effects and the production of supercooled liquid water at low elevations on the upslope side of the Sierra Nevada.During the passage of the surface cold front, the differences in δ¹⁸O at the two sites were quite small probably because the orography plays a less significant role in the precipitation production process during such events.The δ¹⁸O peaked around −13% which translates to an “equivalent temperature” of −10.7°C for ice phase water capture at the upwind site KV. At site HM downwind of the Sierra crest, and 25 km east of KV, the weighted mean ice phase water capture occurred at elevations some 5 to 6°C colder than at KV, because of subsidence and loss of supercooled liquid water in the lower elevations on the lee side.     

Heat flow in the Ozark Plateau, Arkansas and Missouri: relationship to groundwater flow

Heat flow values were calculated from direct measurements of temperature and thermal conductivity at thirteen sites in the Arkansas-Missouri Ozark Plateau region. These thirteen values are augmented by 101 estimates of heat flow, based on thermal conductivity measurements and temperature gradients extrapolated from bottom-hole temperatures. The regional heat flow profile ranges from 9 mW m⁻² to over 80 mW m⁻², but at least two distinct thermal regimes have been identified. Seven new heat flow determinations are combined with three previously published values for the St. Francois Mountains (SFM), a Precambrian exposure of granitic and rhyolitic basement rocks, average 47 mW m⁻². Radioactive heat production of 76 samples of the exposed rocks in the SFM averages 2.4 μW m⁻² and a typical continental basement contribution of 14 mW m⁻² is implied. Conversely, the sedimentary rock sequence of the plateau is characterized by an anomalously low heat flow, averaging approximately 27 mW m⁻². Groundwater transmissivity values that are based on data from 153 wells in deep regional aquifers demonstrate an inverse relationship to the observed heat flow patterns. The areas of high transmissivity that correspond to areas of low total heat flux suggest that the non-conservative vertical heat flow within the Ozark sedimentary sequence can be attributed to the effects of groundwater flow.     

Spatial Accessibility to Health Care Facilities in Suhum District,Ghana

To improve geographical accessibility to health facilities in rural Ghana, it has been recommended that additional health facilities be built. Resource constraints make this recommendation infeasible. Using location-allocation models, this paper demonstrates that in the Suhum District of Ghana substantial improvements in accessibility can be achieved with better locational choices and without additional facilities. Also, additional facilities will produce little improvement in accessibility if location is not explicitly considered. The paper demonstrates the utility of location-allocation models for improving accessibility to services in the Third World.     

Eccentric geomagnetic dipole drift

A recalculation of the rate of westward drift of the eccentric geomagnetic dipole since 1900 has confirmed its correlation with irregularities in the excess length-of-day (LOD) as originally reported by Vestine. The major changes in the LOD curve since 1900 are shown to be well correlated with the westward drift rate from a number of magnetic models covering the interval. A new Magsat model of secular variation for 1980.0 shows no increase in the drift rate which dropped by a factor of three in the interval 1965–1970.     

Emission spectrographic estimation of gold

A procedure for estimating minute quantities (parts per billion) of gold is described, based on dissolution of the sample in aqua regia, adsorption on activated charcoal, arcing of the charcoal ash, and measurement of the intensity of the emitted spectra.     

Field and Laboratory Analyses of Water from the Columbia Aquifer in Eastern Maryland

Field and laboratory analyses of pH, alkalinity, and specific conductance from water samples collected from the Columbia aquifer on the Delmarva Peninsula in eastern Maryland were compared to determine if laboratory analyses could be used for making regional water-quality interpretations. On the basis of 170 field pH and specific conductance measurements, 165 laboratory pH and specific conductance measurements, and 86 field and 135 laboratory alkalinity measurements, a significant difference at the 0.1-percent level was found between laboratory and field analyses of pH and specific conductance. No significant difference was found between laboratory and field analyses of alkalinity. In most samples, laboratory pH was greater than field pH, laboratory specific conductance was less than field specific conductance, and laboratory alkalinity was equally likely to be less than, the same as, or greater than field alkalinity. Kruskal-Wallis tests of field and laboratory data grouped by north-south and east-west coordinates and by land use indicate that the difference between field and laboratory values is usually not enough to affect the outcome of the statistical tests. Thus, laboratory measurements of these constituents may be adequate for making certain regional water-quality interpretations, although they may result in errors if used for geochemical interpretations.     

Comparative growth of juvenile white sturgeon and striped bass: Effects of temperature and hypoxia

The influences of temperature and environmental hypoxia on the growth rates of two California anadromous fishes, white sturgeon (Acipenser transmontanus) and striped bass (Morone saxatilis) were examined. Fish (0.5–0.6 g initial weight) were fedad libitum rations ofArtemia in flow-through aquaria regulated for temperature (15, 20, and 25°C) and oxygen tension (130 and 90 torr P_{o 2}). Growth of sturgeon was significantly greater at 20 °C compared with 15 °C, but there was no difference between 20 and 25 °C. Striped bass growth increased with each 5° increment of temeprature elevation to 3.2% body weight per d at 25 °C, the fastest growth rate measured. The temperature of maximum growth reflected the temperature of the native estuarine rearing area. Environmental hypoxia (90 torr P_{o 2}) reduced growth of sturgeon within each temperature level, whereas striped bass growth was reduced by hypoxia only at the upper two temperatures. Sturgeon were much more active in the growth chambers than striped bass. Sturgeon activity increased with each 5 °C temperature increase under normoxia and hypoxia, except at 25 °C (hypoxia) where activity was insignificantly different from that at 20 °C (hypoxia).     

Recent developments in technological forecasting

Technological forecasting means the prediction of characteristics or use of technology. The methods used by technological forecasters are in principle no different from those used by forecasters in other application areas. However, the unique problems of the field require that the methods be adapted to those problems. This paper discusses recent developments involving refinements in the methods which have been in use for the past several decades. It also describes some important recent work on estimating upper limits to the progress of technologies, and on quantitative measures of multi-attribute technologies. Finally, it discusses several issues common to all forecasting application areas, as they are dealt with in technological forecasting. These issues include validation, disasters of forecasting, determinism in forecasting, and some examples of forecasts with practical applications.