bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribution of Serotonin Transporter Gene Polymorphisms to Pediatric Migraine
Authors: Szilagyi Agnes , Boor Krisztina , Orosz Iren , Szantai Eszter , Szekely Anna , Kalasz Huba , Sasvari‐Szekely Maria , Farkas Viktor
Published: March 2006

Background.—The serotonin transporter gene is a promising candidate locus for the genetic susceptibility of migraine.

Objective.—Two functional polymorphisms of the serotonin transporter gene (5‐HTTLPR and STin2) were analyzed to assess whether these variants are associated with pediatric migraine.

Methods.—Eighty‐seven Hungarian pediatric migraine patients and 464 controls were genotyped using polymerase chain reaction. Patients suffering from migraine with (n = 38) or without aura (n = 49) were interviewed regarding the clinical symptoms before or during the attacks.

Results.—There was no difference between genotype or allele distribution of 5‐HTTLPR and STin2 polymorphisms in the entire group of migraineurs and controls. Analysis of subgroups showed an association between STin2 and migraine with aura, as the 12,12 homozygote genotype was overrepresented in this group of patients. Furthermore, similar allele and genotype patterns were found in cases with severe vomiting and abdominal pain.

Conclusions.—These results confirm and extend the association between the STin2 polymorphism of 5‐HTT gene and migraine with aura using pediatric probands. Our data also suggest a novel endophenotype for pediatric migraine characterized by excessive vomiting and abdominal pain during the attack.
Endothelin Receptor A –231 G>A Polymorphism: No Linkage to Primary Pediatric Headache
Authors: Lisi Veronica , Garbo Greta , Battistella PierAntonio , Miccichè Flavia , Stecca Anna , Terrazzino Salvatore , Franzoi Malida , Tripoli Elisa , Leon Alberta , Clementi Maurizio
Published: March 2006

Objective.—To assess whether the biallelic –231 G>A polymorphism of the endothelin type A receptor (EDNRA) gene, previously shown to be a marker of increased risk for developing migraine, has a role in the susceptibility to primary pediatric headache.

Background.—Several studies suggest that endothelin has a role in migraine. A recent association study has shown that the biallelic –231 G>A polymorphism of the EDNRA gene is associated to migraine in an elderly population.

Methods.—A total of 126 consecutive unrelated pediatric patients affected by primary headache, classified according to the International Headache Society criteria in migraine (migraine with aura, n = 3; migraine without aura, n = 80), and tension‐type headache (episodic tension‐type headache, n = 36; chronic tension‐type headache, n = 7) patients, were recruited to the study. Sixty‐seven healthy blood donors were used as a control group. Genomic DNA was extracted from buccal swabs or blood samples and analyzed by polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) for the above‐mentioned polymorphism. Allele and genotype frequencies for primary headache patients were analyzed in comparison with the control group.

Results.—No significant differences were found in the distribution of the EDNRA –231 G>A polymorphic variant when considering both genotype (migraine χ2= 2.78, P= .25; tension‐type headache χ2= 3.58, P= .17) and allelic frequencies (migraine χ2= 1.48, P= .22; tension‐type headache χ2= 0.39, P= .56). Furthermore, no significant genotype‐related difference was found in relation to clinical features, such as age at onset, frequency, and length of the attacks.

Conclusions.—Our study shows that the –231 G>A polymorphism in the EDNRA gene is neither associated with primary juvenile headache nor significantly correlated with main clinical features characteristic of the headache pathology in pediatric settings.
Thunderclap Stroke: Embolic Cerebellar Infarcts Presenting as Thunderclap Headache
Authors: Schwedt Todd J. , Dodick David W.
Published: March 2006

Thunderclap headache is known to be a presenting feature of subarachnoid hemorrhage, unruptured intracranial aneurysm, cerebral venous thrombosis, cervical artery dissection, spontaneous intracranial hypotension, pituitary apoplexy, retroclival hematoma, and hypertensive reversible posterior leukoencephalopathy. We describe a case of thunderclap headache in the absence of focal, long‐tract, or lateralizing neurological findings, as the primary clinical feature of embolic cerebellar infarcts. This case expands the differential diagnosis of thunderclap headache and reinforces the need for magnetic resonance imaging in the evaluation of such patients, even when neurologic examination, brain computed tomography, and cerebrospinal fluid analysis are normal.
Hemicrania Continua: A Case in Which A Patient Experienced Complete Relief on Melatonin
Authors: Spears Roderick C.
Published: March 2006

This paper reports a case of hemicrania continua in which attacks were successfully eliminated while taking melatonin 7 mg at bedtime after the patient was no longer able to tolerate indomethacin due to gastrointestinal side effects.
Transvenous Pacemaker Lead Removal Is Safe and Effective Even in Large Vegetations: An Analysis of 53 Cases of Pacemaker Lead Endocarditis
Authors: RUTTMANN ELFRIEDE , HANGLER HERBERT B , KILO JULIANE , HÖFER DANIEL , MÜLLER LUDWIG C , HINTRINGER FLORIAN , MÜLLER SILVANA , LAUFER GÜNTHER , ANTRETTER HERWIG
Published: March 2006

Background: The aim of this study was to investigate whether transvenous lead removal is safe and effective in patients with lead vegetations greater than 1 cm in size.

Methods: From 1991 to 2005, a total of 53 patients underwent pacemaker or ICD lead removal for vegetations. Transvenous lead removal using locking stylets and sheaths was performed in 30 patients (56.6%) and was found to be effective in 29 of those patients. In 1 patient, due to rupture of the lead, open heart removal of the ventricular lead remnant and tricuspid valve repair had to be performed due to persistent infection. In 23 of these patients, transesophageal echocardiography (TEE) verified vegetations greater than 1 cm in size. The remaining patients underwent primary lead removal using sternotomy and extracorporeal circulation (ECC). Pacemaker pocket infection was found in 16 patients (55.2%) of the transvenous study group and in 11 patients (45.8%) of the ECC group (P = 0.72).

Results: Perioperative mortality was 5.7% (3 patients); all of them underwent primary ECC removal and had severe endocarditis of the tricuspid valve.

None of the patients who underwent transvenous lead removal died and there were no further complications such as pericardial tamponade or major pulmonary embolism requiring further interventions, even in patients demonstrating large vegetations.

Conclusions: This study demonstrates that transvenous lead removal is a safe and highly effective procedure for the removal of infected pacemaker and ICD leads, even in patients with large vegetations. Embolism to the lung proceeds mainly without further complications; however, patients with vegetations that might obstruct a main stem of the pulmonary artery should undergo ECC removal.
Continuous Template Collection and Updating for Electrogram Morphology Discrimination in Implantable Cardioverter Defibrillators
Authors: COMPTON STEVEN J. , MERRILL JAMES J. , DORIAN PAUL , CAO JIAN , ZHOU DUO , GILLBERG JEFFREY M. ,   on behalf of the “Marquis VR” US/Canada Investigators
Published: March 2006

Introduction: Electrogram morphology analysis improves discrimination of supraventricular tachycardias (SVTs) from ventricular tachycardias (VTs) in implantable cardioverter defibrillators (ICDs), but electrogram morphology may change with lead maturation, drugs, or disease progression. We report the clinical performance of an automatic algorithm that creates and updates templates from non‐paced, slow rhythm and continuously checks the quality of the template used for arrhythmia discrimination.

Methods and Results: We studied this algorithm in 193 patients with single‐chamber ICDs (Marquis VR, Medtronic Inc., Minneapolis, MN, USA). Of the 112 patients who completed 6‐month follow‐up, 99.1% of the patients had ≥1 automatic template created. Match scores between template and ongoing rhythm are computed using Haar Wavelets. Of the 435 automatic templates evaluated at follow‐up, 423 (97.2%) had a median match score ≥70%. Intrinsic rhythm at 1 month had significantly higher match scores (P < 0.001) with automatic templates (90.3 ± 7.0%) than with manual templates (85.7 ± 10.9%) generated at pre‐hospital discharge (PHD). The percentage of appropriately rejected SVTs was slightly higher with the automatic template (280/339 episodes) than with the manual template at PHD (272/339 episodes) while the Wavelet detection of VT was the same (218/220 episodes).

Conclusions: In patients receiving ICDs, the automatic templates were successfully created during a 6‐month follow‐up period, and consistently matched the patients' intrinsic rhythm at the nominal match threshold. Both early (<1 month postimplant) and late (1‐ to 3‐month follow‐up period) changes in electrogram morphology were identified, confirming the need for automatic template updating.
Antiinflammatory Effects of Cardiac Resynchronization Therapy in Patients with Chronic Heart Failure
Authors: THEODORAKIS GEORGE N. , FLEVARI PANAGIOTA , KROUPIS CHRISTOS , ADAMOPOULOS STAMATIS , LIVANIS EFTHIMIOS G. , KOSTOPOULOU ANNA , KOLOKATHIS FOTIS , PARASKEVAIDIS IOANNIS A. , LEFTHERIOTIS DIONYSSIOS , KREMASTINOS DIMITRIOS TH.
Published: March 2006

Background: Cardiac resynchronization therapy (CRT) pacing has been proposed as an additional treatment to medical therapy to improve heart failure patients with left ventricular asynchrony. The aim of this study was to evaluate the influence of CRT treatment on proinflammatory cytokines in patients with heart failure.

Methods: Twenty patients, with a mean age 64 ± 2 years, with severe chronic heart failure NYHA class II–IV (mean ejection fraction 25 ± 2%), were included in the study. Patients were treated with CRT pacing, after failure of optimal therapy. Blood samples were taken at baseline, 3 months after pacing therapy, and after a subsequent 3‐month period of no pacing for the assessment of proinflammatory cytokines TNF‐α and its receptors (sTNFR‐I, sTNFR‐II), IL‐6, adhesion molecules sICAM‐1 and sVCAM‐1, and the apoptotic indices sFas and sFas‐Ligand.

Results: Levels of TNF‐α, sTNFR‐I, and sTNFR‐II were reduced at the end of 3 months of CRT therapy and further reduced at the end of the no pacing period (P < 0.05, compared to baseline). Levels of IL‐6 also declined after 3 months of CRT pacing (from 8.9 ± 2.5 pg/mL to 4.7 ± 1.3 pg/mL, P < 0.05) and this was maintained during the no pacing period (3.9 ± 1.1 pg/mL P < 0.05 compared to baseline). The adhesion molecule sICAM‐1 levels also reduced (from 265 ± 17 ng/mL to 235 ± 12, P < 0.05) after 3 months of CRT pacing and remained unchanged at the end of the no pacing period (219 ± 12 ng/mL, P < 0.05 compared to baseline values).

Conclusion: Major proinflammatory cytokines and the adhesion molecule sICAM‐1 are reduced with CRT therapy and this effect is maintained for at least 3 months after discontinuation of pacing.
X‐Ray Dose Reduction in Fluoroscopically Guided Electrophysiology Procedures
Authors: DAVIES ANDREW G. , COWEN ARNOLD R. , KENGYELICS STEPHEN M. , MOORE JANET , PEPPER CHRIS , COWAN CAMPBELL , SIVANATHAN MOHAN U.
Published: March 2006

This study assessed the efficacy of a new dose reduction regime in fluoroscopically guided electrophysiology (EP) procedures, which included diagnostic electrophysiological investigations, radiofrequency ablation, and biventricular pacing. A modified dose regime for fluoroscopy was implemented in one of our cardiac electrophysiology laboratories. The x‐ray system was programmed with a hierarchy of three fluoroscopy doses, and therefore image quality and settings. The default (lowest) dose mode was not expected to be suitable for all patient sizes or for the entirety of all procedures. Staff raised the dose level in a stepped manner as and when required to optimize the imaging requirements of the procedure. Phantom studies indicated that the low dose mode provided adequate image quality for visualizing EP catheters, while significantly lowering patient skin dose. In 52 clinical cases, questionnaires were used to assess the subjective clinical image quality. The mean image quality score for the low dose setting was rated between “adequate” and “good.” The fluoroscopy dose level was raised from the lowest level for 6% of the total fluoroscopy time. Procedural Dose Area Product (DAP) meter readings were analyzed for patients prior to (n = 85) and after (n = 150) the implementation of the low dose regime and showed an overall reduction in DAP rate of 74%. The hierarchical dose regime proved to be acceptable in routine clinical practice for EP procedures, leading to significant reductions in patient doses.
The Deleterious Consequences of Right Ventricular Apical Pacing: Time to Seek Alternate Site Pacing
Authors: MANOLIS ANTONIS S.
Published: March 2006

Background: The purpose of this article is to critically review the data accumulated to date from studies evaluating the hemodynamic and clinical effects of right ventricular apical pacing during conventional permanent cardiac pacing. The data from studies comparing the effects of right ventricular apical pacing and alternate site ventricular pacing are also reviewed.

Methods: We conducted a MEDLINE and journal search of English‐language reports published in the last decade and searched relevant papers.

Results: Although intraventricular conduction delay in the form of left bundle branch block (LBBB) has traditionally been viewed as an electrophysiologic abnormality, it has now become abundantly clear that it has profound hemodynamic effects due to ventricular dyssynchrony, especially in patients with heart failure. These deleterious effects can be significantly ameliorated by cardiac resynchronization therapy effected by biventricular or left ventricular pacing. However, not only is spontaneous LBBB harmful, but the iatrogenic variety produced by right ventricular apical pacing in patients with permanent pacemakers may be equally deleterious. In this review new evidence from recent studies is presented, which strongly suggests a harmful effect of our long‐standing practice of producing an iatrogenic LBBB by conventional right ventricular apical pacing in patients receiving permanent pacemakers. This emerging strong new evidence about the adverse hemodynamic and clinical effects of right ventricular apical pacing would dictate a reassessment of our traditional approach to permanent cardiac pacing and direct our attention to alternate sites of pacing, such as the left ventricle and/or the right ventricular outflow tract or septum, if not for all patients, at least for those with left ventricular dysfunction. Indeed, current convincing data on alternate site ventricular pacing are encouraging and this approach should be actively pursued and further investigated in future studies.

Conclusions: Not only is spontaneous permanent LBBB harmful to our patients, but the iatrogenic variety produced by right ventricular apical pacing during conventional permanent pacing may also be deleterious to some patients. The compelling evidence presented herein cannot be ignored; it may dictate a change of attitude toward right ventricular apical pacing directing our attention to alternate sites of ventricular pacing and avoidance of the right ventricular apex.
Monomorphic Ventricular Tachycardia Induced by Cardiac Resynchronization Therapy in Patient with Severe Nonischemic Dilated Cardiomyopathy
Authors: BORTONE AGUSTÍN , MACIA JEAN‐CHRISTOPHE , LECLERCQ FLORENCE , PASQUIÉ JEAN‐LUC
Published: March 2006

We report the case of a patient with severe nonischemic dilated cardiomyopathy in whom cardiac resynchronization therapy (CRT) was the source of incessant, drug‐resistant, monomorphic ventricular tachycardia (VT). VT recurrences were only resolutive with inactivation of CRT and reactivation of CRT reproduced VT occurrence. The possible pathophysiology of the VT and the potential ventricular proarrhythmic risk related to CRT are discussed. This report points out clearly that CRT can induce ventricular arrhythmias and suggests the need for CRT systematically associated with a defibrillation system.
Preparation and Optical Properties of Transparent Eu3+:Y3Al5(1−x)Sc5xO12 Ceramics
Authors: Feng Tao , Shi Jianlin , Jiang Danyu
Published: March 2006

Using a novel combustion method, Eu‐doped Eu:yttrium aluminum garnet (YAG) and Eu:YSAG powders, and transparent Eu:YSAG ceramics were fabricated. The optical properties of these transparent ceramics have been measured, and a reduced peak splitting of Eu3+ for 5D0→7F1 and 5D0→7F2 was observed when 10 at.% Al3+ was substituted by Sc3+. The enhanced symmetry of the Eu sites in YAG lattice, which resulted from the expanded YSAG lattice by Sc3+ doping, is the main reason for the reduced peak splitting.
The {111} Growth Twins in Tetragonal Barium Titanate
Authors: Wu Yu‐Chuan , Lee Che‐Chi , Lu Hong‐Yang , McCauley Daniel E. , Chu Mike S.H.
Published: March 2006

The {111} twins frequently observed in pressureless‐sintered BaTiO3 ceramics have been analyzed by the X‐ray diffractometry, scanning and transmission electron microscopy. Both the single twins and double lamellar twins are growth (or annealing) twins. The twins lying in the {111} mirror planes, which is not one of the symmetry elements of the (basic) crystal lattice's but that of the superlattice's, are therefore superlattice twins. The {111} twins, particularly the double twins, were found more frequently from samples sintered in an Ar atmosphere of lower oxygen partial pressure (pO2). Further decreasing of pO2 using the Ar‐5% H2 mixture has rendered the sintered samples entirely of hexagonal BaTiO3, the 6H‐polytype. The formation of such twins is attributed to changing of the corner‐sharing TiO6 octahedra to Ti2O9 face‐sharing octahedra, which accommodates for local oxygen deficiency in tetragonal BaTiO3. The stacking sequence alters accordingly from c‐layer (constituting the 3C‐polytype, treating tetragonal pseudo‐cubic) to h‐layer (as in (chc)1(chc)2 of 6H).
Effect of Sintering Additives on Superplastic Deformation of Nano‐Sized β‐Silicon Nitride Ceramics
Authors: Xu Xin , Nishimura Toshiyuki , Hirosaki Naoto , Xie Rong‐Jun , Yamamoto Yoshinobu , Tanaka Hidehiko
Published: March 2006

The effect of sintering additives on superplastic deformation of nano‐sized β‐Si3N4 ceramics has been studied by compression tests at 1500°C. The sintering additives were (i) Y2O3+Al2O3; (ii) Y2O3+MgO; and (iii) Y2O3. Nano‐sized Si3N4 ceramics with different sintering additives had similar microstructures. For the first two sintering additives, the stress exponents were determined to be ∼2 at a lower stress region and ∼1 at a higher stress region, where the strain rate was dependent on sintering additives only at the higher stress region, and was independent at the lower stress region. Nano‐ceramics with Y2O3 additives had only one region, which had a stress exponent of ∼1 within the stress range that we studied. The results could be explained by the different deformation mechanisms at the higher and lower stress regions and the influence of viscosity of liquid phase on the transition stress.
Computational Design for Grain‐Oriented Microstructure of Functional Ceramics Prepared by Templated Grain Growth
Authors: Itahara Hiroshi , Tani Toshihiko , Nomura Hiroshi , Matsubara Hideaki
Published: March 2006

We have developed a computational model using Monte Carlo simulation in order to design grain‐oriented microstructures of ceramics processed by templated grain growth for functional materials with anisotropic grain growth due to anisotropy in interfacial energies. The current model with plate‐like template particles expressed the development of grain‐oriented microstructures with the low interfacial energy planes well faceted. In addition, the proposed model gave a guiding principle for optimizing the initial parameters (i.e., ratio of templates to total solid particles, initial size and aspect ratio of template particles, and amount of liquid phase), leading to highly grain‐oriented ceramics with improved performances.
A Kinetic Model for Oxidation of Si–Al–O–N Materials
Authors: Chou Kuo‐Chih
Published: March 2006

In this paper a new model has been proposed to describe the oxidation of Si–Al–O–N materials in both isothermal and non‐isothermal conditions in the form of powders and pellets. All these formulae are analytic with a form of explicit function; therefore, they are not only easy to use but also enable the easy performance of a theoretical analysis. The application of these formulae to practical systems shows that this model is feasible; moreover, these formulae can not only be used to treat the oxidation for Si–Al–O–N materials but also be applied to treat reactions in other fields of materials.
Geological History, Flora, and Vegetation of Xishuangbanna, Southern Yunnan, China1
Authors: Zhu Hua , Cao Min , Hu Huabin
Published: March 2006

Xishuangbanna of southern Yunnan is biogeographically located at a transitional zone from tropical Southeast (SE) Asia to subtropical East Asia, and is at the junction of the Indian and Burmese plates of Gondwana and the Eurasian plate of Laurasia. The flora of the region consists of a recorded 3336 native seed plant species, belonging to 1140 genera in 197 families, among which 83.5 percent are tropical genera and 32.8 percent are endemic to tropical Asia, suggesting a strong affinity to tropical Asian flora. The vegetation of Xishuangbanna is organized into four forest types: tropical rain forest, tropical seasonal moist forest, tropical montane evergreen broad‐leaved forest, and tropical monsoon forest. The tropical rain forest in Xishuangbanna has the same floristic composition of families and genera as some lowland equatorial rain forests in SE Asia, and is dominated (with a few exceptions) by the same families both in species richness and stem dominance. The exceptions include some deciduous trees in the canopy layer, fewer megaphanerophytes and epiphytes, and a higher abundance of lianas and microphyllic plants. We consider the tropical rain forest of Xishuangbanna as a type of tropical Asian rain forest, based on their conspicuous similarities in ecological and floristic characteristics.
Ground‐Water Flow Systems and Stability of a Slope
Authors: Sterrett Robert J. , Edil Tuncer B.
Published: March 2006

Shoreline recession on the Great Lakes has caused millions of dollars worth of property damage in the lake bordering States and Canadian provinces. A variety of projects have been funded to study the erosion problem. The general conclusion of these studies is that wave action at the base of the bluff is the most important basic cause of bluff‐top retreat. The purpose of this study was to investigate the role of various physical processes in causing bluff erosion. One part of the study was to ascertain the role of ground water in bluff stability. In this study, along a certain stretch of the Lake Michigan shoreline, 9 to 10 m (27 to 30 ft) per year of bluff‐top recession that is not correlated to toe erosion was recorded. Heads were measured in 25 piezometers and a complex ground‐water flow system was defined at this site. A glacial sand unit that is under artesian pressure was found 5 m (15 ft) above the toe of the bluff. Another “perched” system was observed in a fractured till unit at the top of the bluff. Water‐table fluctuations have been recorded over a year and fluctuations of up to 13 m (39 ft) in the lower sand unit were measured. These fluctuations were found to have a significant influence on bluff stability. Pore pressures calculated from field measurements, along with the effective strength parameters of the soil units, were then used in the slope stability analysis to determine safety factors.

Ground‐water flow systems are found to be highly complex at the land‐lake interface due to the inhomogeneities of the glacial materials that compose the bluffs. Furthermore, these complex ground‐water flow systems influence the stability of the upper part of the bluffs. Because of the complexities, extrapolation of results to other stretches of the shoreline is difficult. However, methodologies and the awareness of how water‐table fluctuations and multi‐layered ground‐water flow systems affect slope stability can be of help in other field situations.
Barriers to Effective Ground‐Water Management: The California Casea
Authors: Knapp Keith , Vaux H. J.
Published: March 2006

Ground water meets 40% of California's annual water needs, yet is essentially unmanaged. Current overdrafting is of special concern because supplemental surface supplies are becoming scarcer and more expensive. A dynamic optimization model is used to show that potential benefits from management in the southern San Joaquin area may be substantial. The magnitude of these benefits is sensitive to costs of energy, interest rates, demand for water, and availability of substitute surface supplies. The distribution of benefits from management depends upon the regulatory strategy employed. Collectively, pumpers gain through quota regulation but lose with pump taxes. Individual pumpers may lose even if the collective group benefits.

Existing arrangements for ground‐water management in California appear inadequate. Statutes permit State regulation of withdrawals where water quality is threatened but only if additional surface supplies are provided. Management may be initiated in the courts at considerable cost. Historically, court action has required supplemental surface supplies. Legal authority exists for local control of withdrawals but has never been used.

Resistance to ground‐water management in California is widespread and stems from the perception that regulation may impose real losses on individual users even if the majority benefits. Individual fears of economic loss borne for the collective and uncertain gain to larger group constitutes a significant barrier to management Effective management policies will need to be simple, flexible, equitable and inexpensive to administer.
Economics of Declining Water Supplies in the Ogallala Aquifera
Authors: Warren John , Mapp Harry , Ray Daryll , Kletke Darrel , Wang Charles
Published: March 2006

A large portion of northwest Oklahoma is situated over the Ogallala Aquifer. Economic growth in the region has been tied closely to irrigated agriculture which depends on declining ground‐water resources in the Ogallala formation.

As part of an integrated six‐State study, Oklahoma researchers developed a computer model of the agricultural sector of northwestern Oklahoma and estimated irrigated and dryland cropping patterns, farm output and farm income over a 40‐year planning horizon. Projections were made for a “baseline” situation, and the sensitivity of these results to alternative assumptions on energy costs, commodity prices and technological development was also analyzed.

Preliminary results of the baseline analysis suggest a favorable outlook for irrigated agriculture in the area through the near to mid‐term, with increases in irrigated acreage, production, and returns to land and management. However, the baseline case is dependent on several relatively optimistic assumptions regarding future fuel prices, yields, and agricultural commodity prices. Even fairly large changes in fuel prices and yields are not particularly critical for model results, but if agricultural commodity prices are substantially lower than projected, the outlook for irrigated agriculture in the area is not favorable.
Ground‐Water Development in Western River Basins: Large Economic Gains with Unseen Costsa
Authors: Daubert John T. , Young Robert A.
Published: March 2006

In river basins where aquifers are closely interrelated with a stream, large‐scale ground‐water development can lower water tables near the stream and diminish stream flows. Junior surface right holders are adversely affected. A digital computer simulation of the hydrologic‐economic system on the lower South Platte River in Colorado is employed to study economic impacts of two water management policies. Open access management is found to yield high income benefits but imposes substantial costs on surface‐water users when water supplies are limited. Incorporation of ground water into the appropriation system can help avoid the losses to surface‐water users, but greatly reduces the income of ground‐water users.
Ground‐Water Management in Basaltsa
Authors: Shelton M. L.
Published: March 2006

Basalts are a major source of ground water throughout the Columbia River Plateau region of the Pacific Northwest. Development and management of ground water in these basalts are complicated by the spatial variability of the hydrologic characteristics of the deep, stratified lava flows, but new irrigation developments and municipal and industrial water needs are placing increasingly larger demands on the ground‐water resource. Water management decisions are aided by individual basin studies that contribute to greater understanding of the regional ground‐water system. A distributed‐system multiple‐storage model for the Deschutes River Basin, Oregon, reveals the magnitude of spatial differences in ground‐water recharge, storage, and discharge for this watershed. Input‐output analysis elucidates the functional characteristics of the basin groundwater system, and it identifies the presence and magnitude of interbasin linkages in the ground‐water system. Implementation of ground‐water development strategies based on storage and transmission characteristics simulated by the model demonstrates that basin or regional perspectives are necessary to fully utilize ground‐water storage in basalts.
Cyclic Storage: A Preliminary Assessment
Authors: Lettenmaier Dennis P. , Burges Stephen J.
Published: March 2006

The performance of a simplified water resource system consisting of a single surface reservoir and adjacent aquifer storage operated as a coupled flow buffering device is investigated on an annual scale to provide insight into the most important physical and climatic (streamflow) parameters governing cyclic storage performance. The hypo thetical system is fully characterized by aquifer capacity, pumping and recharge capacity, surface storage size, annual demand, and reservoir inflow statistics, including annual mean, coefficient of variation, skew coefficient, lag one correlation coefficient, and Hurst coefficient. System performance under a range of these parameters is reviewed via Monte Carlo simulation; for the cases considered system performance is almost always limited by total system storage (sum of surface and aquifer storage). A preliminary economic analysis indicates that the cost of providing flow buffering via development of subsurface storage is about an order of magnitude less than for surface storage in the cases considered.
Sulfate‐Reducing Bacteria in Ground Water from Clogging and Nonclogging Shallow Wells in the Netherlands River Region
Authors: van Beek C.G.E.M. , van der Kooij D.
Published: March 2006

The majority of well fields in the river region in the Netherlands, where anaerobic water is withdrawn from the shallow aquifer, have problems with well clogging. In order to test the supposition that sulfate‐reducing bacteria play a role in this clogging process, sulfate‐reducing bacteria in water from wells on well fields with and without the occurrence of clogging were enumerated. In water withdrawn from nonclogging wells, the Most Probable Number of sulfate‐reducing bacteria averaged 5 per 100 ml, whereas in wells subject to clogging, the number averaged 25 per 100 ml. A statistical analysis by Wilcoxon's order test confirmed that a significant difference exists between the numbers of sulfate‐reducing bacteria in clogging and nonclogging wells. The mechanism whereby sulfate‐reducing bacteria contribute towards this type of well clogging is as yet unclear.
Analysis of Leaky Aquifer Pumping Test Data: An Automated Numerical Solution Using Sensitivity Analysis
Authors: Cobb P. M. , McElwee C. D. , Butt M. A.
Published: March 2006

The Kansas Geological Survey is pursuing an effort to automate some of the more common methods of aquifer pumping‐test analysis. This paper discusses the results of work done on the leaky artesian aquifer as defined by Hantush and Jacob (1955). The paper covers the basic theory of the aquifer type, the numerical solution of the leaky artesian‐well function, and the methodology of achieving the “best fit” parameters in the least squares' sense. Several data sets are used to demonstrate the applicability of the proposed technique. These examples indicate the generally satisfactory results produced by the automated analysis documented here.

The algorithm has good convergence properties. Initial estimates for the aquifer parameters may vary by about three orders of magnitude above or below the correct values. For typical data sets the rms fitting error should be less than a few tenths of a foot. If this is not the case, one is probably not dealing with a simple leaky aquifer. This method of pumping‐test analysis does not eliminate the role of an experienced hydrologist to define the local hydrogeology and aquifer type. However, once the decision is made as to which aquifer configuration is being observed, this program will, in a quick and unbiased fashion, give an accurate assessment of the leaky‐aquifer parameters within the limits of the theoretical approximations and the data quality.
Evaluation of Electromagnetic Methods for Rapid Mapping of Salt‐Water Interfaces in Coastal Aquifers
Authors: Stewart Mark T.
Published: March 2006

In coastal areas salt‐water intrusion represents a significant threat to water quality in coastal aquifer systems. The electromagnetic method evaluated in this study proved to be rapid, very inexpensive, and it yields results which agree well with geologic and geochemical surveys using direct sampling. The instrument reads directly in conductivity units and the depth of investigation is constant for a particular spacing and orientation of the receiver and transmitter coils. Data can be obtained and interpreted by personnel with little technical training. Data interpretation normally involves producing terrain conductivity contour maps, but quantitative solutions can be obtained where the geoelectric section can be reasonably approximated by a two‐layer section. Some problems were experienced with interference. However, interference sources usually were very localized and could be avoided.

This study, conducted in two areas of Florida, demonstrates that the EM conductivity method is very useful for rapid, inexpensive ground‐water surveys where the objective is to locate zones of conductive pore fluids at depths less than 30–40 meters. Although interpretation is indirect and qualitative, neither data aquisition nor interpretation require special training. This characteristic of the EM method makes it very suitable for use by agencies where highly‐trained technical personnel are not available.
Numerical Simulation of Thermal Energy Storage Experiment Conducted by Auburn University
Authors: Sykes J. F. , Lantz R. B. , Pahwa S. B. , Ward D. S.
Published: March 2006

A multidimensional, finite‐difference model for ground‐water flow and heat transport is used to analyze the thermal energy storage experiment conducted by Auburn University in Mobile, Alabama. The experiment consisted of three stages–namely, injection, storage and recovery occurring for 80, 51 and 41 days, respectively. This application demonstrates the validation evidence that the model adequately and accurately simulates the field experiment. The numerical model includes the effects of: hydraulic anisotropy, thermal convection and conduction, and heat loss to the adjacent confining strata. Observed aquifer isotherms at the end of each stage are compared with predicted values on a cylindrical grid situated about the well. The degree of vertical discretization used in the model is shown to impact the predicted temperature profiles at each stage, but has minimal effect on the recovery water temperature.
In‐Situ Determination of Three‐Dimensional Aquifer Permeabilities
Authors: Way Shao‐Chih , McKee Chester R.
Published: March 2006

In conventional methods of aquifer tests, homogeneous and isotropic formations are assumed. In many instances, however, aquifers are anisotropic. To resolve this problem, three‐dimensional flow equations in homogeneous, anisotropic and leaky aquifers are derived. With the equation and method outlined in the report, we can determine the three components of directional permeability (x, y, and z) in the presence of leakage, and determine the statistical distribution of fractures and stream channels. Field tests that verify our theory are presented.
Nitrate Distribution in the Ground Water of the Alliston Region of Ontario, Canada
Authors: Hill A. R.
Published: March 2006

Nitrate‐N concentrations during the Summers of 1980 and 1981 exceeded 10 mg/1 in 68 of the 164 ground‐water samples collected from a shallow water‐table aquifer underlying a sand plain near Alliston, Ontario. Three extensive zones of nitrate contamination were associated with major potato‐growing areas on the sand plain. Nitrate concentrations were positively correlated with both the percentage area of heavily fertilized crops (potatoes, corn, sod and asparagus) and nitrogen fertilizer application rates in the vicinity of ground‐water sampling sites. Chloride levels in ground water exhibited a positive association with KCl fertilizer application rates. Ground water under potato fields had relatively consistent C1/NO3‐N ratios despite considerable variations in nitrate‐N and chloride concentrations. Ground water with a low nitrate content was found beneath forest and permanent pasture. These data suggest that the use of commercial nitrogen fertilizer is a major source of nitrate in the aquifer.
Degradation of Phenolic Contaminants in Ground Water by Anaerobic Bacteria: St. Louis Park, Minnesota
Authors: Ehrlich G. G. , Goerlitz D. F. , Godsy E. M. , Hult M. F.
Published: March 2006

Coal‐tar derivatives from a coal‐tar distillation and wood‐treating plant that operated from 1918 to 1972 at St. Louis Park, Minnesota contaminated the near‐surface ground water. Solutions of phenolic compounds and a water‐immiscible mixture of polynuclear aromatic compounds accumulated in wetlands near the plant site and entered the aquifer. The concentration of phenolic compounds in the aqueous phase under the wetlands is about 30 mg/1 but decreases to less than 0.2 mg/1 at a distance of 430 m immediately downgradient from the source. Concentrations of naphthalene (the predominant polynuclear compound in the ground water) and sodium (selected as a conservative tracer) range from about 20 mg/1 and 430 mg/1 in the aqueous phase at the source to about 2 mg/1 and 120 mg/1 at 430 m downgradient, respectively. Phenolic compounds and naphthalene are disappearing faster than expected if only dilution were occurring. Sorption of phenolic compounds on aquifer sediments is negligible but naphthalene is slightly sorbed. Anaerobic biodegradation of phenolic compounds is primarily responsible for the observed attenuation. Methane was found only in water samples from the contaminated zone (2‐20 mg/1). Methane‐producing bacteria were found only in water from the contaminated zone. Methane was produced in laboratory cultures of contaminated water inoculated with bacteria from the contaminated zone. Evidence for anaerobic biodegradation of naphthalene under either field or laboratory conditions was not obtained.
Approximating Pollutant Transport to Ground Watera
Authors: Enfield Carl G. , Carsel Robert F. , Cohen Stuart Z. , Phan To , Walters David M.
Published: March 2006

Three simplistic models are developed for evaluating the transport of organic pollutants through soil to ground water. The models consider mobility and first‐order degradation. The first calculates linear sorption/desorption of the pollutant and first‐order degradation without considering dispersion. The second is similar to the first but also considers dispersion. The third considers nonlinear sorption following a Freundlich equation and first‐order degradation but does not consider dispersion. The models are compared to field data for the pesticides aldicarb and DDT. The models projected a lower mobility for DDT than was observed in the field.
GROUND‐WATER DISPERSION CALCULATIONS WITH A PROGRAMMABLE CALCULATOR
Authors: Kelly William E.
Published: March 2006

Abstract. A simple and convenient method for calculating two‐dimensional dispersion on a TI 58 or 59 programmable calculator utilizing the normal distribution program available in the Solid State Software Master Library module as a subroutine is presented with an example.
ISOTOPES IN GROUND‐WATER INVESTIGATIONS
Authors: Toran Laura
Published: March 2006

During the past 20 years, hydrologists have made increasing use of isotopes to obtain a better theoretical and practical understanding of ground water. The distribution of isotopic species in water provides information on sources of ground water, on flow paths and mixing, and on physical and chemical characteristics of aquifers.

Numerous examples in the literature illustrate the techniques and applications of isotopes to ground‐water studies. Isotopes have helped solve problems as diverse as what is a fair tax rate for people using imported water in a California water district, and why Venice is sinking. Demands are increasing for better understanding of hydrologic systems to facilitate management of water as a resource, and to evaluate environmental problems. Thus, we can anticipate isotopes will be used more and more in hydrologic studies.
The Use of Microorganisms as Ground‐Water Tracers: A Review
Authors: Keswick Bruce H. , Wang De‐Shin , Gerba Charles P.
Published: March 2006

Microbial contamination of ground water results in numerous disease outbreaks each year. Tracing their movement in ground water is therefore essential. Bacteria, viruses, yeasts and spores have been used for this purpose and to trace underground movement of water in much the same manner as chemical tracers are used. Chemical tracers do not always reflect the movement of microorganisms in ground water. The use of certain bacteria and animal viruses is undesirable due to their pathogenic potential and difficulties in their differentiation from background, naturally‐occurring organisms. Bacterial viruses appear to be the microorganisms most suited as a microbial tracer because of their size, ease of assay and lack of pathogenicity. Bacteriophages have been used to trace ground‐water movement over distances of 1,600 meters and can be used under a variety of conditions.
Hydraulic Conductivity of a Glacial Till in Albertaa
Authors: Hendry M. James
Published: March 2006

Soils underlain at shallow depths (less than 1 m, 3 ft) by glacial till are generally considered undesirable for irrigation because of their unfavourable internal drainage characteristics. In some areas of southern Alberta, Canada, soils developed upon shallow tills have been irrigated successfully for over 60 years with no adverse effects on the soil. An investigation was conducted to describe the hydro‐geologic properties of till under one of these areas and to assess the properties with regard to drainage. Study techniques consisted of detailed test drilling and sampling, excavation of test pits, installation and monitoring of ground‐water instrumentation, field and laboratory hydraulic conductivity testing and tritium analyses of ground‐water samples. Two fracture sets were found in this till. Both sets of fractures produce secondary permeabilities which mask the low hydraulic conductivity of the till matrix (10−10m·s−1). Small‐scale fractures which have a fracture spacing of approximately 10 mm (0.4 in.) have an apparent mean hydraulic conductivity of 5 × 10−9m·s−1, whereas large‐scale fractures which have fracture spacings from 20 mm (0.8 in.) to over 630 mm(2 ft) have an apparent mean hydraulic conductivity of approximately 2 × 10−7m·s−1. The high hydraulic conductivity of the large‐scale fractures was corroborated by tritium analyses of ground‐water samples. Tritium analyses also indicate the presence of recent water at depth in the till. The large‐scale fractures, which control the bulk hydraulic conductivity of this till, provide conduits through which infiltrating water can be transmitted to the ground‐water regime. These fractures are believed to be the reason why this land has remained irrigable for over 60 years.
Determining Hydraulic Conductivity Distributions in a Mountainous Area Using Mathematical Modeling
Authors: Jamieson Gordon R. , Freeze R. Allan
Published: March 2006

Meager Mountain is a recently‐active andesite‐dacite volcano situated 160 km NNW of Vancouver, British Columbia. The mountain is presently being jointly evaluated by the Geological Survey of Canada and the British Columbia Hydro and Power Authority as a potential geo‐thermal resource. Limited existing and field‐generated geological and hydrogeological data were employed to evaluate the ground‐water flow regime at the study area. Mathematical modeling was carried out to determine the feasible range of ground‐water‐flow characteristics in the area. Field observations indicate that the water table is located at an intermediate elevation in the mountain system with the discharge area confined to the portion of the valley covered by unconsolidated deposits. Water balance calculations for the Lillooet River basin and baseflow determinations in the Meager Creek basin indicate that 14 to 17% of the total precipitation recharges the ground‐water system. Various possible geological configurations were mathematically modeled with the water‐table configuration and recharge rates restricted to the above ranges. The model results were used to predict the variations in the hydraulic conductivity in each geological formation. The results fell into a discrete range of values thought to be within an order of magnitude of the actual values.
Lower Hawthorn Aquifer on Sanibel Island, Florida
Authors: Motz Louis H.
Published: March 2006

In 1977, the Island Water Association (IWA) on Sanibel Island, Florida, was concerned that the total dissolved solids concentrations in several wells in its well field were increasing and might cause the blended raw water to exceed the design capacity of its electrodialysis plant. Test wells were drilled several miles west of the existing well field, and two pumping tests, one at the site of the test wells and the other in the existing well field, were run. Average values for the transmissivity (T), storage coefficient (S), and leakance (K′/b′) of the lower Hawthorn aquifer were determined to be T = 1,290 ft2/d (119 m2/d), S = 2.7 × 10−5, and K′/b′= 7.47 × 10−6 (1/d). The results of the pumping tests and other findings indicated that pumpage from the lower Hawthorn aquifer was being derived from artesian storage in the aquifer and from vertical leakage into the aquifer from adjacent formations. It was estimated that the IWA would be able to recover usable water from the lower Hawthorn aquifer for about 5 more years by drilling new wells in the vicinity of the test wells and in other nearby areas that might be determined to yield usable water. After this period of time, it likely would become increasingly difficult, if not impossible, to obtain large quantities of usable water from the lower Hawthorn aquifer, unless significant quantities of water could be found in areas in which few data were then available. The principal recommendations, which subsequently were acted upon by the IWA, were to conduct drilling and testing in the lower Hawthorn aquifer several miles west of the test wells and to investigate the underlying Suwannee aquifer and deeper zones as possible sources of large quantities of brackish water.