bluuebunny/crossref_metadata_2025 huggingface dataset:
Refractory Status Epilepticus: Is EEG Burst Suppression an Appropriate Treatment Target during Drug-Induced Coma? What is the Holy Grail?
Authors: Bergey Gregory K.
Published: July 2006

Refractory Status Epilepticus: Effect of Treatment Aggressiveness on Prognosis

Rossetti AO, Logroscino G, Bromfield EB

Arch Neurol 2005;62(11):1698–1702

Background

Administration of antiepileptic drugs for coma induction in refractory status epilepticus (RSE) has not been widely studied. Moreover, the effect on outcome of electroencephalographic (EEG) burst suppression remains unclear.

Objective

To investigate whether various coma-inducing options are associated with different prognoses after RSE.

Design

Retrospectively assessed case series.

Setting

Two tertiary referral hospitals in Boston, Massachusetts.

Patients

Among 127 consecutive episodes (107 patients) of status epilepticus, we identified episodes that were refractory to first-line and second-line antiepileptic drugs, needing induced coma with barbiturates, propofol, or midazolam for clinical management.

Main Outcome Measures

Short-term mortality and prevalence of return to functional baseline after the acute episode of status epilepticus were analyzed in relation to demographic and clinical variables and to treatment option (antiepileptic agents and EEG burst suppression).

Results

Forty-nine episodes of RSE (47 patients) were found, occurring more frequently in incident than in recurrent episodes of status epilepticus ( p = .06). Mortality was 23% for patients with RSE and 8% for those without RSE ( p = .05). Return to baseline occurred more often in the non-RSE group ( p = .04). In 20 (61%) of 33 monitored episodes, EEG burst suppression was achieved. Demographic data, clinical variables, and outcome did not differ significantly with the various coma-inducing agents or between episodes with and without EEG burst suppression.

Conclusions

Refractory status epilepticus is more prevalent in incident than in recurrent status epilepticus and is associated with higher mortality; clinical status is less likely to return to baseline than with non-RSE. Outcome was independent of the specific coma-inducing agents used and the extent of EEG burst suppression, suggesting that the underlying cause represents its main determinant.
Inhibitory GABA Current Rundown in Epileptic Brain: Use-Dependent and Pathology-Specific Mechanisms
Authors: Janigro Damir
Published: July 2006

Rundown of GABA Type A Receptors Is a Dysfunction Associated with Human Drug-Resistant Mesial Temporal Lobe Epilepsy

Ragozzino D, Palma E, Di Angelantonio S, Amici M, Mascia A, Arcella A, Giangaspero F, Cantore G, Di Gennaro G, Manfredi M, Esposito V, Quarato PP, Miledi R, Eusebi F

Proc Natl Acad Sci U S A 2005;102(42):15219–15223

Pharmacotherapeutic strategies have been difficult to develop for several forms of temporal lobe epilepsy, which are consequently treated by surgical resection. To examine this problem, we have studied the properties of transmitter receptors of tissues removed during surgical treatment. We find that when cell membranes, isolated from the temporal neocortex of patients afflicted with drug-resistant mesial temporal lobe epilepsy (TLE), are injected into frog oocytes they acquire GABA type A receptors (GABAA-receptors) that display a marked rundown during repetitive applications of GABA. In contrast, GABAA-receptor function is stable in oocytes injected with cell membranes isolated from the temporal lobe of TLE patients afflicted with neoplastic, dysgenetic, traumatic, or ischemic temporal lesions (lesional TLE, LTLE). Use-dependent GABAA-receptor rundown is also found in the pyramidal neurons of TLE neocortical slices and is antagonized by BDNF. Pyramidal neurons in cortical slices of a traumatic LTLE patient did not show GABAA-receptor rundown. However, the apparent affinity of GABAA-receptor in oocytes microtransplanted with membranes from all of the epileptic patients studied was smaller than the affinity of receptors transplanted from the nonepileptic brain. We conclude that the use-dependent rundown of neocortical GABAA-receptor represents a TLE-specific dysfunction, whereas the reduced affinity may be a general feature of brains of both TLE and LTLE patients, and we speculate that our findings may help to develop new treatments for TLE and LTLE.
Age and Gender Difference in ST Height at Rest and after Double Autonomic Blockade in Normal Adults
Authors: Endres Susanne , Mayuga Kenneth A. , De Cristofaro Alessandro , Taneja Taresh , Goldberger Jeffrey J. , Kadish Alan H.
Published: July 2006

Background: ST elevation is commonly seen in young, healthy men. The exact mechanisms that cause ST height to be greater in young men are not yet completely understood. The purpose of the present study was to determine whether autonomic tone is responsible for age and gender differences in ST height.

Methods: Gender and age differences in ST height were studied at rest and after double autonomic blockade (DAB) with atropine and propranolol. Fifty healthy men and women were included (16 men, 14 women, age 23–32 years; 9 men, 11 women, age 65–79 years). Twelve‐lead ECGs were registered at rest and after DAB. Leads II and V1–V4 were chosen for analysis. ST height (in mm) was measured manually at the J‐point, and 40 ms and 80 ms after the J‐point. Values were corrected for QRS amplitude.

Results: Gender and age differences in ST height were seen in both rest and DAB data. Men had greater ST height compared to women at J‐point, 40 and 80 ms after the J‐point (P ≤ 0.0001), and younger subjects had greater ST height than older subjects at J‐point (P = 0.0140), 40 and 80 ms after the J‐point (P ≤ 0.0001). DAB did not change ST height at J‐point or at 40 ms, but increased ST height at 80 ms. Women had less of an increase in ST height following DAB than men did.

Conclusions: ST elevation in the absence of structural or electrical heart disease is mainly seen in young men. Age and gender difference persist after DAB and thus are not due to differences in autonomic tone.
The effect of deficiencies of calcium or of calcium and vitamin D on the rate of oral collagen synthesis in the rat
Authors: Oliver W. M. , Leaver A. G. , Scott P. G.
Published: July 2006

Eighten black and white weanling rats were divided equally into three groups, and each group received a diet which was either adequate in all respects, deficient in calcium only or in calcium and vitamin D. After 7 weeks each rat received an intra‐peritoneal injection of 3H‐proline (5μ Ci/g body weight; 578 m Ci/mM) and was sacrificed 5 hours later. The buccal mucosa and the attached gingiva were removed, the unbound labelled proline removed by dialysis and salt soluble and insoluble tissue fractions were separated by dialysis and filtration. Each fraction was gelatinised then hydrolysed and hydroxyproline estimation and tritium counting were carried out on the hydrolysate.

Larger amounts of insoluble than of salt soluble collagen were recovered. Labelled proline was incorporated in measurable amounts into the insoluble collagen in the relatively short interval before sacrifice. The specific activities of the salt soluble collagen were greater than those of the insoluble collagen and showed greater variation within each dietary group.

The rate of incorporation of labelled proline into insoluble oral collagen in rats deficient in calcium was significantly (p = 0.01) greater than normal and was significantly decreased (p = 0.01) in rats deficient in calcium and vitamin D.
Electron microscopic study of the junction between surgically denuded root surfaces and regenerated periodontal tissues
Authors: Listgarten Max A.
Published: July 2006

The ultrastructural features of the junction between regenerated periodontal tissues and surgically exposed root surfaces were investigated in monkeys. Specimens were studies at intervals of 1 to 18 months. Specimens at all time intervals demonstrated regeneration of the junctional epithelium to both dentin, as well as cementum surfaces. Epithelial reattachment was present on intact, as well as altered root surfaces. Cemental regeneration was also noted in all specimens, but ap‐ peared generally confined to the most apical portion of the wound. Cementum formed over dentin, as well as cementum. A dense, granular layer, possibly of a polysaccharide‐protein nature, was frequently noted at the interface of new cementum and the surgically exposed dentin or cementum. Artifactitious splits, apparently occurring during the demineralization phase of tissue processing, frequently involved this granular layer. It is suggested that these splits result from processing and do not reflect a lack of cohesion or adhesion within the regenerated periodontium. This investigation was supported by the United States Public Health Service, Center for Oral Health Research, University of Pennsylvania, Grant No. DE‐02623. The technical assistance of Miss Rollande Tremblay and J.P. Smith is gratefully acknowledged.
Waste Management Activities in the Atomic Energy Commission
Authors: Belter Walter G.
Published: July 2006

The technical and administrative aspects of radioactive waste management in the light of existing experience and knowledge is discussed. This discussion is related to possible future requirements for the adequate engineering, public health and administrative control of radioactive effluents from various nuclear energy activities.

The variety of radioactive wastes are categorized in a general way on the basis of their hazard potential to emphasize that the problem of radioactive waste management has numerous facets and is not amenable to a single, universal solution. The role of specific environments in waste disposal practices is summarized and the basic approaches (“dilute and disperse” and “concentrate and contain”) to effluent control are defined. Distinction is made between basic radiation protection standards or guides, and operating or performance criteria that must be established in connection with effluent control operations in order to assure the protection of public health and safety.

Examples of radioactive waste disposal practice and experience in the United States for different types of wastes are described and tentative conclusions are drawn regarding the capabilities and limitations of these practices.

The scope and objectives of the research and development program in this field are summarized. The status of work in major waste disposal development projects is noted.

Development of guides and criteria and their application in establishment of health and safety regulations and other pertinent administrative procedures is discussed. The utilization, to the maximum practicable extent, of existing laws and administrative procedures in existing agencies at various levels of government is suggested as being advantageous from an administrative and public relations standpoint.

Economic factors related to handling and disposal of radioactive wastes are noted, including relation of nuclear plant location to disposal requirements. It is pointed out that, although total costs for treatment and disposal are substantial, the cost per unit of electrical energy produced is a rather small percentage of the total cost per unit of energy.
Some Aspects of Sampling Salty Ground Water in Coastal Aquifersa
Authors: Kohout F. A. , Hoy N. D.
Published: July 2006

Investigations of the fluctuations of chloride content in wells that tap the zone of diffusion between fresh and salt water show that the salty well water behaves erratically when the well is pumped. Frequently, a static distribution of chloride content that ranges from less than 1,000 ppm at the top to more than 10,000 ppm at the bottom is present in the open‐hole part of a well. When the well is pumped, the discharge water tends to come from the upper part of the open hole because less energy is expended by removal of low‐density water from this region than by removal of high‐density water from the lower part of the open hole. Where the permeability of strata in the deep part of the open hole is greater than that in the shallow part, the tendency for natural selection of the less dense, shallow water is suppressed, and practically all the water in the blend comes from the deep part.

As a result of this complex interrelation of hydraulics, distribution and density of the salt water, and permeability, the depth at which the pumped water enters the well bore is indeterminate. This deficiency leads to the use of multiple‐depth‐bottle, windshield‐wiper, and electrical‐conductivity sampling techniques for collection of data used in constructing maps and cross sections that show the areal‐depth relations of salt water in the Biscayne aquifer of the Miami area, Florida.
Hydraulic Characteristics of Fractured and Jointed Rocka
Authors: Lewis D. C. , Burgy R. H.
Published: July 2006

Hydrogeologic studies in foothill watersheds have included diamond‐core drilling, installation of observation wells, and pumping tests. Detailed study of recovered cores has provided reasonable estimates of porosity. Pumping tests of the two‐inch diameter wells have given estimates of the transmissibilities ranging from 6 to 600 gallons per day per foot. Test data from several wells indicate that the hydraulics of water movement in jointed rock systems is not governed by the usual mathematical models.
Estimating Transmissibility with One Drawdown
Authors: Ogden Lawrence
Published: July 2006

In an effort to find a method of determining aquifer transmissibility with an abbreviated pumping test the basic equations governing the Theis non‐equilibrium method of determining aquifer constants were examined. They show the relationships of the coefficients of storage and transmissibility. Rearranged in terms of T (transmissibility) and equated to eliminate that parameter, the expression is rewritten as
image

The left side of the equation can be computed from existing tables. All parts of the right side of the equation can be measured during a test except S, the coefficient of storage. Assuming a value for it and measuring distance from the pumping well, drawdown, time, and pumping rate, uW(u) can be computed. The single value of u corresponding to this can be determined from tables or a curve, and the calculation of transmissibility using the available data is the simple final step.

Computations were made over a wide range of actual and hypothetical examples, and it was found that for a range in assumed values of coefficient of storage of 4,000 times, the range in coefficient of transmissibility was between 1.52 and 3.22 times. The method was tested using actual well data with the conclusion that it is reasonably reliable if used in an unconfined aquifer after about three hours of pumping and making drawdown measurements in the pumping well or in an observation well less than 25 feet from the pumping well. Calculations involving a confined aquifer suggest that the method is applicable within a shorter time and over larger distances from the pumping well
Relations of Fresh and Salty Ground Water along the Southeastern U. S. Atlantic Coasta
Authors: Wait R. L. , Callahan J. T.
Published: July 2006

Studies of the hydrogeologic environments and the dynamic and equilibrium relations of fresh and salt water in aquifers have been intensified at several places along the southeastern Atlantic Coast. Some salt‐water problems involve the coastal water‐table aquifer, and others involve parts of the artesian system.

On the sandy coastal islands of North Carolina, freshwater lenses under water‐table conditions float on salt water. Salt‐water contamination may take place by (1) lateral encroachment from the ocean and bay; (2) vertical encroachment from below; (3) overland inundation by ocean water during storms; and (4) downward percolation of salt spray and salt‐bearing precipitation.

In the Savannah, Georgia, and South Carolina area, salt‐water encroachment along two of five water‐bearing zones in the principal artesian (limestone) aquifer has been caused by the decline of artesian pressure due to pumping. Some wells in the limestone at nearby Parris Island, South Carolina, yield salty water when overpumped. From Savannah southward at least to Fernandina, Florida, connate salty water occurs in the artesian aquifer below the fresh water. At Brunswick, Georgia, connate salty water is stratified between fresh‐water bodies in the limestone aquifer above depths of 2,000 feet. Connate salty water has contaminated the aquifer between depths of 500 and 800 feet in a small area in the city.

Along the southeast Florida coast drainage canals have been the primary cause of salt‐water contamination of the highly permeable Biscayne aquifer. Criteria have been established for the operation of salinity‐control dams to prevent encroachment. The salt‐water front in the aquifer along the coast is dynamically stable under natural conditions.
Hydrogeologic Factors in Problems of Contamination in Arid Landsa
Authors: Maxey G. B. , Farvolden R. N.
Published: July 2006

The ideal hydrologic system in arid lands includes a recharge area in mountains and a discharge area in lowlands, a system modified in nature by geologic and physiographic factors. Population and agricultural activity concentrates in valleys, usually in zones of ground‐water discharge. Most water‐supply, contamination and disposal problems arise from this combination of features.

The suitability of hydrogeologic units for any function of operations involving water supply or waste disposal depends primarily on their position within the hydrologic system and secondarily on physical properties. For example, at the Nevada Test Site the ground‐water flow system is used to good advantage, whereas at Las Vegas, 70 miles away, the methods of disposal practiced are in direct conflict with the system.
Removal of ABS and Other Sewage Components by Infiltration Through Soilsa
Authors: Page H. G. , Wayman C. H.
Published: July 2006

The nature and extent of movement of ABS (alkylben‐zenesulfonate) and other sewage components through natural soils were studied in the laboratory and in the field north of Denver, Colorado. Small amounts of ABS and bacteria pass through soils and reach the zone of saturation, where they move laterally down‐gradient several thousand feet. Total dissolved solids show little fluctuation during such movement, possibly because extracted solutes are replaced by other solutes leached from the soils during water infiltration.

In laboratory studies Denver sewage‐plant effluent was filtered through packed columns of 8 types of soils. ABS was not significantly removed by most of the soils; how‐ever, muck, greensand marl, and residual basalt soil ini‐tially removed up to 94 percent of the ABS. Some ABS was removed only after development of bacterial slime on the soils; subsequent infiltration caused leaching of the slime and its adsorbed ABS and other constituents. All soils initially removed about 90 percent of the bacteria within a few feet of travel, but a small percentage passed through the soil. Bacterial clogging occurred quickly in the fine soils but only in modest amounts in the coarse sand, even after three months of flow.

Field studies included analyses of river and irrigation water contaminated from a sewage‐plant effluent, and well water from selected sites down‐gradient between unlined irrigation ditches and the river. Concentrations of ABS and bacteria were significantly reduced during infiltration of irrigation ditch water to the water table. As noted in the laboratory the concentrations of both of these contaminants can be reduced through soil filtering action. In addition there may be some dilution of the infiltrate by the ground water. Dissolved solids showed practically no change between the ditches and the wells.
The Design and Use of Hydrogeologic Mapsa
Authors: Warman J. C. , Wiesnet D. R.
Published: July 2006

A map should treat the critical problems in a way understandable to the intended reader. Some maps appropriately show only one or two pertinent hydrogeologic parameters. Point‐data maps make little or no interpretation of the data. Four‐dimensional maps‐those that include an elapsed span of time or projection of hydrogeologic variables into the future‐represent a high degree of interpretation of data; they are most useful to the map reader. The hydro‐geologist has an obligation to his reader to design maps that are as useful as possible.
California's Stake in the Colorado Rivera
Authors: Cole D. E.
Published: July 2006

California has an enormous stake in the Colorado River. In the southern portion of the State, 80 percent of the water used is furnished by the Colorado River, and this area needs still more water in the immediate years ahead. But it cannot get more from the natural supply of the Colorado. The river is already over‐committed, and California in fact may have to cut back on its present take from that source. This is not the Colorado River in Texas; Los Angeles has gone hundreds of miles to get water, but has not reached that far east‐yet.
Use of Analog Model to Predict Streamflow Depletion, Big and Little Blue River Basin, Nebraskaa
Authors: Emery P. A.
Published: July 2006

The States of Nebraska and Kansas are negotiating a compact for apportionment of the waters of the Big and Little Blue Rivers. So that the negotiating officials could allocate the water equitably, the amount of streamflow depletion caused by ground‐water withdrawals upgradient from the State line needed to be determined. At the request of the Nebraska officials, the U. S. Geological Survey constructed an electric analog model which could be used to determine the amount of streamflow depletion expected to occur in the next 60 years.

The model simulates hydraulic conditions in an area of 7,400 square miles which includes the entire area drained by the Big and Little Blue Rivers in Nebraska. The trans‐missibility of the aquifer (Pleistocene in age) ranges from less than 1,000 to as much as 300,000 gallons per day per foot, and the storage coefficient averages about 0.20. The transmissibility values are based on examination of test‐ hole samples from more than 400 test holes in and adjacent to the basin.

Analysis of the model indicates that predicted maximum ground‐water withdrawals between 1962 and 2022 will not deplete the base flow of the Big or Little Blue Rivers by more than 5 percent.
Data Requirements and Preliminary Results of an Analog‐Model Evaluation—Arkansas River Valley in Eastern Coloradoa
Authors: Moore John E. , Wood Leonard A.
Published: July 2006

The intensively irrigated Arkansas River Valley in Colorado is underlain by a valley‐fill aquifer resting in a U‐shaped trough cut in relatively impermeable Cretaceous rocks. Ground water is pumped to supplement surface water; in the last 10 years pumping has more than doubled. Ground water is closely related to the Arkansas River; percolation from irrigation recharges the aquifer, which discharges into the river. Pumping has resulted in a reduction in streamflow because it intercepts water that ordinarily would have reached the river. The 1,500 irrigation wells in the Arkansas Valley withdrew 230,000 acre‐feet of water in 1964.

An analog model is being used to evaluate the relation of ground water to surface water and to predict effects of changes in water management. The model, simulating a 150‐mile reach of the Arkansas Valley (Pueblo to the State line), has a resistor spacing of 8 per modeled mile. The framework for the model was a transmissibility map; transmissibility ranges from less than 50,000 to 700,000 gallons per day per foot. Specific yield averages about 0.2. Hydrologic boundaries, such as the Arkansas River, and the bedrock valley‐fill contact were simulated. Applied water, precipitation, evapotranspiration, and ground‐water pumping were the independent variables programed. The model is being verified by comparing predicted changes in water level and river discharge with observed changes.
The Influence of Ground‐Water Flow Systems on Pavement Stability in Highway Cuts
Authors: Williams R. E.
Published: July 2006

The failure or “breaking up” of pavement in cuts in glacial till is a phenomenon commonly observed in northeastern Illinois and other areas in the midwest. Failure commonly follows periods of significant ground‐water recharge, especially when such periods are concomitant with freezing and thawing conditions.

Water levels in piezometers installed in glacial till in northeastern Illinois indicate that during periods of high precipitation or rapid snow melt, the potential surface normally occurs at shallow depths. Therefore, cuts of appreciable depth intersect the zone of saturation and establish local, gravity, ground‐water flow systems with the bottom of the cut acting as a ground‐water discharge zone. Such shallow gravity flow systems may bring about pavement failure by facilitating the growth of thick ice lenses or by developing high pressure beneath the pavement due to poor drainage.
Designing Pumped Well Characteristics into Electric Analog Models
Authors: Prickett T. A.
Published: July 2006

Passive‐element electric analog models have been used for many years as a means of tudying cause and effect relationships in the regional development of ground‐water resources. Although successful use of such models has been demonstrated by several investigators, certain inherent characteristics designed into some electric analog models lead to significant error at particular boundaries of the model.

Errors that exist at the pumped well junctions of non‐steady‐state two‐dimensional flow electric analog models are analyzed. The results of the analysis indicate that practical sustained yields and water‐level data derived from pumped well junctions of electric analog models lead to overly optimistic estimates of aquifer and well yielding capabilities. This paper presents design methods for simulating pumped wells having different radii, screen lengths, partial penetrations, gravel pack sizes, and well‐loss constants.
Electric‐Analog and Digital‐Computer Model Analysis of Stream Depletion by Wellsa
Authors: Jenkins C. T.
Published: July 2006

Electric‐analog or digital‐computer models are used to compute the effect of ground‐water withdrawal or recharge on streamflow. The results can be generalized on a map showing lines of equal elapsed time. The lines indicate the time of recharging or discharging that is needed to affect the streamflow by a given fraction of the amount pumped or injected. The generalization is based on the similarity in shape of the relations between pumping time and stream depletion for (1) semi‐infinite homogeneous aquifers drained by a straight, fully penetrating stream, and (2) complex heterogeneous aquifers. Response curves from a model reflect the combined effect of stream sinuosity, irregular impermeable boundaries, areal variation in aquifer properties, and imperfect hydraulic connection between the stream and aquifer. The elapsed‐cime lines are identified by sdf (stream depletion factor) values. These values can be calculated from observations made on an electric‐analog model and then may be used in a digital‐computer program for determining the effects of ground‐water pumping or recharge on streamflow.
Well Logging in Ground‐Water Hydrologya
Authors: Keys W. Scott
Published: July 2006

In 1966 more than 50 billion gallons of water was pumped daily from an estimated 10 to 15 million water wells in the United States. This was more than one‐sixth of the national withdrawal of water. On the basis of past rates of increase, a much greater future use of ground water is suggested. Our annual investment in water wells is one‐half to three‐quarter billion dollars, not including pumps and plumbing. In 1964 approximately 436,000 new wells were drilled; however, less than 1 percent of these wells were logged by any geophysical means. The application of _ge_o.phy.sical well logging to ground‐water hydrology is comparable to its use in petroleum exploration in the 1930's; however, we can take advantage of equipment and interpretation techniques developed in the oil industry that are available now for use in ground‐water investigations.

Although most petroleum well logging techniques may be utilized in hydrology; modifications in equipment and interpretation are necessary because of basic economic and environmental differences between petroleum and ground‐water evaluation. If logging is to be widely applied to ground‐water exploration and evaluation, the expense of equipment and services must be reduced. Fortunately, this can be accomplished, because most water wells are not as deep as oil wells and the temperatures and pressures are lower.

The Water Resources Division of the U. S. Geological Survey is conducting research on the application of borehole geophysics to ground‐water hydrology. The following logging devices are utilized in the evaluation of ground‐water environments: spontaneous potential, resistivity, gamma, gamma‐gamma, neutron, radioactive tracer, flowmeter, caliper, fluid resistivity, gradient and differential temperature, and sonic velocity. Lightweight logging sondes and control modules are operated by one man, either on a vehicle‐mounted 6,000‐foot logger or on a suitcase‐mounted 500‐foot logger. An inexpensive magnetic tape system has been developed and is used routinely for log recording and playback.

If commercial well logging service is to be widely used in ground‐water exploration and development, water well contractors, and State and municipal agencies must be educated on the advantages of obtaining more information from each hole drilled. It will be necessary also to demonstrate how well logging can provide much of this information. In addition, the well logging industry must adapt their equipment and services to the requirements of ground‐water hydrology. The need for additional logging capability in this field exists at the present time and is expected to increase. Hopefully industry will be able to fill the gap.
Design of Waste Disposal Wellsa
Authors: Marsh John H.
Published: July 2006

In this paper, basic design principles for disposal wells are set out and then exemplified by discussion of two recently constructed wells for disposal of very corrosive refinery waste. One well is designed for 700 gpm of waste containing 4200 ppm hydrogen sulfide. The other is designed for 50 gpm of waste containing 32 percent hydrochloric acid. Both wells are in the Gulf Coastal Plain and are completed in a deep, unconsolidated fine sand containing salt water. Screens fabricated from exotic metals were incorporated in the design. Unique combinations of materials were used for the casing.

It is pointed out that oil field type completions are often used in disposal well construction, which usually results in low specific injection capacity, high operation and maintenance costs, and short useful life of the hydraulic structure.
The Floridan Aquifer in Northeast Floridaa
Authors: Leve G. W.
Published: July 2006

The Floridan aquifer in northeast Florida is comprised of limestone and dolomite beds of Tertiary age. These formations in ascending order are: the Cedar Keys Formation of Paleocene age; the Oldsmar Limestone, Lake City Limestone, Avon Park Limestone, and the Ocala Group, all of Eocene age; locally the Suwannee Limestone of Oligocene age; and limestone and sand beds at the base of the Hawthorn Formation of Miocene age. The top of the Ocala Group ranges in elevation from 100 feet above sea level to 550 feet below sea level throughout the area.

Except in the western part of the area where the Ocala Group is at the surface, impermeable beds in the Miocene to Recent deposits overlie the aquifer and confine the water under artesian pressure. Hard, impermeable beds within the aquifer separate the water‐bearing zones. The coefficient of transmissibility ranges from about 50,000 gpd/ft (gallons per day /foot) to more than 1,000,000 gpd/ft and the coefficient of storage ranges from 1.5 × 10−4 to 1.7 × 10−2 in areas where the water in the aquifer is under artesian conditions.

The estimated annual recharge averages one‐half mgd (million gallons per day) in the western part of northeast Florida and 45 mgd in the south central part. Limited recharge also occurs throughout the central and eastern part of northeast Florida by downward leakage of water through the overlying confining beds. The coefficient of leakance of these confining beds ranges from about 1.7 × l0−2 to 1 ×10−3 gpd/ft3.

Natural discharge occurs by perennial and intermittent springs and upward leakage through the confining beds in the areas of artesian flow. Artificial discharge by wells occurs principally in the farming, urban, and industrial areas in the eastern part of northeast Florida.

Between 1940 and 1962 artesian pressures declined from 5 to 25 feet throughout the eastern part of northeast Florida.

Seasonal declines of artesian pressure of 5 to 10 feet in the farming areas resulted in temporary increases of chloride content of water of 200 to 500 ppm (parts per million). The chloride content of water in the aquifer in the vicinity of Jacksonville and Fernandina has increased from 22 to 1400 ppm in wells more than 1,400 feet deep. Thus far, impermeable zones below the fresh water have prevented serious salt‐water contamination in shallower wells at Jacksonville and Fernandiua.
Monitoring of Changes in Quality of Ground Watera
Authors: LeGrand Harry E.
Published: July 2006

Ground water of acceptable quality is commonly interspersed with water of inferior quality. Water of inferior quality may be naturally occurring salty water commonly underlying fresh water, or it may be enclaves of contaminated water from wastes that lie in the fresh‐water bodies. Disposal of wastes on and in the ground and pumping of water from wells cause a dispersion of contaminated water; migration of contaminated water toward wells may be spontaneously induced by the natural hydraulic gradient, or it may be induced artificially by the cone of depression about one or more wells. Economic methods of determining precisely the boundary zones between contaminated and uncontaminated water are not available. Much reliance is placed on monitoring wells.

A prerequisite to monitoring is a synthetic hydrogeologic framework or model in which the behavior of the contaminated water is conceived. Such a conceptual model, using pertinent data that are available, helps to assess the need for monitoring and to guide a monitoring program for optimum results. Unplanned, indiscriminate monitoring of water from wells is expensive, inefficient, and fallible. The need for monitoring will increase in the future; yet, the proper objective is to improve the technology of determining the distribution of contaminated water so that monitoring can be minimized and conducted with optimum results.
Geophysical Logging and Hydraulic Testing, Pahute Mesa, Nevada Test Sitea
Authors: Blankennagel Richard K.
Published: July 2006

The U. S. Geological Survey, on behalf of the U. S. Atomic Energy Commission, performs a broad range of geologic and hydrologic studies related to underground nuclear explosions at the Nevada Test Site. One phase of the studies involved extensive geophysical logging and hydraulic testing in deep exploratory holes at Pahute Mesa, Nevada Test Site. Various geophysical logs and hydraulic testing techniques used in the study are described in this paper.

Interpretations of logs and logging techniques depend on factors such as rock characteristics in a particular area, drilling methods, and the objectives of the hydrologic investigations. From experience gained at Pahute Mesa, some qualitative data on rock lithologies and hydraulic conditions in the borehole may be determined by electric, caliper, temperature, and fluid resistivity logs. Quantitative data on the major water‐yielding intervals in the borehole are obtained from radioactive tracer or spinner surveys. Interpretations of the geophysical logs have been verified by isolating specific zones in the drill holes with inflatable packers and spacers. These intervals were tested by injection or swabbing of fluid and measuring the resultant change in water level caused by fluid outflow from or inflow to the interval of rock isolated by the packers.
Volume of Aquifer Tested for Permeability During a One‐Well Pumping Test
Authors: Strausberg Sanford I.
Published: July 2006

Pumping test data from a single well were used to estimate aquifer volume affecting drawdown. After four days of pumping from a 240 feet thick welded tuff aquifer in southern Nevada, the volume of the wedge‐shaped mass tested was estimated to be about 15.6 billion cubic feet (440 million cubic meters). The field coefficient of permeability of the aquifer is 275 gallons per day per square foot.
Cones of Influence Developed in the Silurian‐Devonian Aquifer, Maumee River Basin, Ohio
Authors: Rowland Mark R. , Kunkle George R.
Published: July 2006

In the Maumee River Basin of northwestern Ohio the principal source of ground water is the Silurian‐Devonian carbonate aquifer. The use rate of ground water from this aquifer could rapidly increase many fold in the near future. This situation demands quantitative information on the resource potential of the aquifer, if proper development is to be encouraged.

A relationship between ground‐water use and recharge rates through an analysis of the cones of influence is demonstrated in this paper. Computed recharge rates for the cones of influence vary from 6,800 to 75,300 gpd/sq mi, and the variation is systematic in that the higher recharge rates correlate with the higher pumpage rates. Recharge rates appear to have an upper limit of approximately 100,000 gpd/ sq mi, which corresponds to a maximization of the vertical hydraulic gradient. Although maximization of the vertical hydraulic gradient is impossible to achieve for a given cone of influence, it can be approached by lowering the piezometric surface of the aquifer by increasing the pumpage rate.

Assuming that the safe yield of an aquifer is equivalent to the rate of recharge, this study demonstrates that development of an aquifer can increase many times its potential.
Electric Well Logging of Hawaiian Basaltic Aquifers
Authors: Peterson Frank L. , Lao Chester
Published: July 2006

An extensive program of electric well logging has been conducted in Hawaii during the past three years to determine the applicability of this tool to the volcanic environment which exists in Hawaii. Electric well logging techniques were found to be useful in Hawaiian basaltic aquifers; however interpretation of both spontaneous potential logs and resistivity logs varies from the conventional interpretation of electric logs in sediments. The interpretation of fluid conductivity logs in Hawaii follows conventional water well techniques.

The analysis of spontaneous potential and resistivity well logging in basalts, which constitute most of the Hawaiian aquifers, poses problems because of the relatively uniform composition of the basalts and the complex relation of porosity to resistivity in basaltic aquifers, and because logging usually is performed in water‐filled boreholes. Spontaneous potentials are thought to result primarily from fluid flow rather than from electrochemical potential, and positive SPs generally indicate zones with flow from the aquifers into the well, and negative SPs generally indicate zones with little flow or flow from the well into the aquifer. Resistivity logs indicate the location, number, individual thickness, and total thicknesses of permeable and less permeable formations, and are useful as indicators of water‐yielding zones. High resistivities generally are indicative of dense impermeable basalts and low resistivities are indicative of porous permeable zones most likely to contribute water to the borehole. Both resistivity and spontaneous potential logs provide a direct measurement of depth to water, depth of casing, and depth of hole.
Type‐Curve Solution of Step‐Drawdown Test
Authors: Sheahan N. Thomas
Published: July 2006

A set of type‐curves is presented which simplifies and quickens the solution of the Rorabaugh equation for drawdown in a pumping well by eliminating the trial‐and‐error computations. Type‐curve analysis of test data in the field, before pumping is discontinued, provides an indication of the accuracy and adequacy of test data points. For optimum accuracy, test data should cover the portion of maximum curvature of the curve, and the range between the lowest and the highest pumping rates used in the step‐drawdown test should be great enough to define a unique curve.
Recharge Characteristics of a Watercourse Aquifer System at Springfield, Ohioa
Authors: Norris Stanley E. , Eagon Herbert B.
Published: July 2006

An investigation was made of infiltration conditions in the alluvial‐filled Mad River valley in the vicinity of the Springfield municipal wells. The study shows that most recharge to the 100‐foot thick sand and gravel aquifer is from induced infiltration from the Mad River. Local precipitation and natural, down‐valley underflow also are important in sustaining the 14 mgd (million gallons per day) pumping rate.

The investigation was designed to learn more about rates of streambed infiltration. Gaging stations were established at points above and below the well field in the expectation that infiltration losses could be measured directly. The attempt was unsuccessful because infiltration losses proved too small to measure accurately by ordinary stream gaging methods. The investigation has, nevertheless, provided much new data about this important watercourse aquifer system.

Observation‐well records covering the 4‐year period 1965 through 1968 show that ground‐water levels follow an annual cycle, typically rising in the period February through June, when recharge exceeds depletion, and falling during the remainder of the year. The rate of induced stream infiltration is not sufficient to prevent perennial dewatering of the aquifer beneath the streambed. The water table beneath the center of the losing reach ranges in depth from about 17 feet in January to about 6 feet in June in the average year. Bedrock highs beneath the stream, which result in local thinning of the aquifer upstream and downstream from the well field, essentially limit infiltration to a reach about 2½ miles long having an area of approximately 24 acres. During the 7‐month depletion period average infiltration is estimated at 9 mgd and during the 5‐month accretion period estimated infiltration is 12 mgd. On the basis of these estimates the infiltration rate for the respective periods is 0.37 and 0.50 mgd per acre, or about 0.35 mgd per acre per foot of depth.
Observations on Water Content Changes in Stratified Sediments During Pit Rechargea, b
Authors: Wilson L. G.
Published: July 2006

Two pit recharge tests were conducted at an instrumented research site near Tucson, Arizona using cooling tower blowdown effluent from a nearby power plant. The first trial in 1966 consisted of 142 days of continuous inundation. The second test in 1968, comprised 15 wet‐dry cycles with a total inundation time of 80 days. Quantities recharged by the two management techniques were contrasted. Water content profiles, obtained via a “moisture logger” in 14 access wells, clearly delineated two principal zones of water transmission on mounds within stratified materials of the 80 ft zone of aeration at the site. During the continuous inundation test three stages were apparent in the history of these mounds: growth stage, equilibrium stage and drainage stage. It was possible to relate these various stages to intake characteristics of the pit. The development of models to characterize recharge within the zone of aeration in areas of the Tucson basin with geological controls similar to those at the recharge site, should accommodate the three stages in the history of mound development and dissipation.
Replenishment Sources of the Alluvial Aquifers of the Peruvian Coast
Authors: Gilboa Yaakov
Published: July 2006

Ground water in the arid coastal area of Peru occurs in more than fifty alluvial aquifers. The aquifers are limited to river valleys and to nearby sedimentary plains.

The coast is rainless and the river valleys serve as the drainage outlet of the western slopes of the Andes. The coastal alluvial aquifers are located below the lower limit of the active catchment areas, and are not recharged directly by precipitation.

The long igneous batholith and the volcanic formations of the Andean Cordillera form an impermeable barrier which prevents the replenishment of the aquifers by underflow from the Andes.

The main source of replenishment of the aquifers in the Peruvian coastal zone is river water. The water infiltrates through the river beds and irrigation canals and migrates laterally within the alluvial deposits. Another important source of recharge is return flow from irrigation. Water also enters the aquifers through boundary faults.
Factors Affecting the Validity of Chemical Analyses of Natural Water
Authors: Summers W. K.
Published: July 2006

Chemical analyses of natural water may be inadequate because of inadvertent human errors and sample aging. Characteristic deficiencies can be demonstrated by multiple chemical analyses of the same sample by different laboratories, multiple analyses of the same sample by one laboratory, repeated analyses of one sample as a function of time, and a simple laboratory experiment in rock‐water chemistry. Whenever possible, complete chemical analyses should be made. The most reliable analyses are those in which combining weights of the cation equal the combining weight of the anion and in which the sum of the individually measured constituents equals the observed residue on evaporation at 180°C (total dissolved solids).
Application of Nonparametric Statistical Tests in Hydrogeology
Authors: Siddiqui S. H. , Parizek R. R.
Published: July 2006

Appropriate nonparametric or distribution free statistical techniques are useful tools when data do not satisfy the conditions required by parametric statistical tests, and may be applied to a variety of hydrogeological problems. Two nonparametric tests, Krusk‐Wallis One‐Way Analysis of Variance and Mann‐Whitney U Test, were used to test the significance of observed differences in well yields with respect to variation in controlling hydrogeologic factors. This paper presents the steps involved in performing these two tests with one example for each and suggests other applications to water‐related problems. To avoid computational errors and save time, a computer program was written for calculating the statistics used in these tests.
Infill of Nuclear Rubble Chimneys by Ground Watera
Authors: Fenske Paul R. , Charnell Robert L.
Published: July 2006

This paper presents some of the preliminary results of a theoretical analysis of the ground‐water infill rate of a rubble chimney produced by an underground nuclear explosion. The study was conducted to evaluate effects that various features of the hydrogeology regime have on rate of infill. This model for infill is based on the analogy of a rubble chimney to a small diameter gravity well. The infill history is approximated by integrating production from a series of steady state infill rates based on Dupuit‐Forchheimer assumptions. The model has been used for parameter sensitivity analysis. Of the aquifer characteristics, changes of the hydraulic conductivity have the greatest effect on infill; the radius of influence is most sensitive to changes in the specific yield. The effect of infill rate of using a rubble porosity that decreases with depth is small, although initial infill is more rapid. The hydrogeology data from two events where infill data are available have been used with this model for verification. For both BILBY and GREELEY events, agreement between measured and calculated infill data are good. BILBY data suggest that substantial dewatering of the rubble in the chimney occurred before much ground water entered the chimney. Comparison of the GREELEY data indicates that dewatering of the rubble is minimal but that porosity of the rubble near the surface was higher than originally anticipated.