bluuebunny/crossref_metadata_2025 huggingface dataset:
Exhumation, doming and slab retreat in the Betic Cordillera (SE Spain):in situ40Ar/39Ar ages andP–T–d–tpaths for the Nevado‐Filabride complex
Authors: AUGIER R. , AGARD P. , MONIÉ P. , JOLIVET L. , ROBIN C. , BOOTH‐REA G.
Published: July 2005

The combination of metamorphic petrology tools andin situlaser40Ar/39Ar dating on phengite (linking time of growth, compositions andP–Tconditions) enables us to identify a detailedP–T–d–tpath for the still debated tectonometamorphic evolution of the Nevado‐Filabride complex and infer new geodynamic‐scale constraints. Our data show an isothermal decompression (at 550 °C) from 20 kbar for the Bédar‐Macael unit and 14 kbar for the Calar Alto unit down toc.3–4 kbar for both units at 2.8 mm year−1. At 22–18 Ma, this first part of the exhumation is followed by a final exhumation at 0.6 mm year−1along a high‐temperature low‐pressure (HTLP) gradient ofc. 60 °C km−1. The age of the peak of pressure is not precisely known but it is shown that it is around 30 Ma and possibly older, which is at variance with recent models suggesting a younger age for high‐pressure (HP) metamorphism. Most of the exhumation is related to late‐orogenic extension fromc. 30 to 22–18 Ma. Thus the formation of the main ductile extensional shear zone, the Filabres Shear Zone (FSZ), occurred at 22–18 Ma and is clearly associated with a top‐to‐the‐west shear sense once the FSZ is well localized. The transition from ductile to brittle then occurred atc. 14 Ma. The final exhumation, accommodated by brittle deformation, occurred fromc. 14 to 9 Ma and was accompanied, from 12 to 8 Ma, by the formation of nearby extensional basins. The duration of the extensional process isc.20 Myr which argues in favour of a progressive slab retreat fromc. 30 to 9 Ma. The change in the shape of theP–Tpath at 22–18 Ma together with strain localization along the main top‐to‐the‐west shear zone suggests that this date corresponds to a change in the direction of slab retreat from southwards to westwards.
Thermal gradients in the Sri Lankan granulite terrane: a garnet–biotite thermometric approach
Authors: SAJEEV K. , OSANAI Y.
Published: July 2005

Thermal zoning of the Highland Complex, Sri Lanka has been delineated using the Fe2+–Mg distribution coefficient between garnet and biotite from garnet–biotite gneiss samples collected with wide geographical distribution. In order to minimize the potential for retrograde Fe–Mg exchange and maximize the potential for retaining peak equilibrium KD (garnet–biotite) and temperature, garnet and biotite included within feldspar and quartz without other mineral inclusions have been selected. The calculated results indicate four distinct temperature contours with KD values varying from 1.84 to 6.38 and temperature varying from 996 to 591 °C. From the present results, it is possible to divide the Highland Complex into two major metamorphic zones: a high‐temperature area in the central region and a low‐temperature area in the south‐western and north‐eastern region. In conjunction with the metamorphic pressure variations estimated from the granulites of the Highland Complex in previous studies, it is shown that the high‐ and low‐temperature areas are complemented by a high‐pressure region towards the eastern side and a low‐pressure region towards the western side of this complex. This thermal dome is interpreted to be an artifact of the different crustal levels exhumed following Pan‐African metamorphism.
Five generations of monazite in Langtang gneisses: implications for chronology of the Himalayan metamorphic core
Authors: KOHN M. J. , WIELAND M. S. , PARKINSON C. D. , UPRETI B. N.
Published: July 2005

Monazite grains from Greater Himalayan Sequence gneisses, Langtang valley, Nepal, were chemically mapped and then dated in situ via Th–Pb ion‐microprobe analysis. Correlation of ages and chemistry reveals at least five different generations of monazite, ranging from c. 9 to >300 Ma. Petrological models of monazite chemistry provide a link between these generations and the thermal evolution of these rocks, yielding an age for the melting of Greater Himalayan rocks within the Main Central Thrust sheet (c. 16 Ma), and for the timing of thrust sheet emplacement that are younger than commonly viewed. Chemical characterization of monazite is vital prior to chronological microanalysis, and many ages previously reported for monazite from the Greater Himalayan Sequence are interpretationally ambiguous.
Y‐chromosome Lineages from Portugal, Madeira and Açores Record Elements of Sephardim and Berber Ancestry
Authors: Gonçalves Rita , Freitas Ana , Branco Marta , Rosa Alexandra , Fernandes Ana T. , Zhivotovsky Lev A. , Underhill Peter A. , Kivisild Toomas , Brehm António
Published: July 2005

A total of 553 Y‐chromosomes were analyzed from mainland Portugal and the North Atlantic Archipelagos of Açores and Madeira, in order to characterize the genetic composition of their male gene pool. A large majority (78–83% of each population) of the male lineages could be classified as belonging to three basic Y chromosomal haplogroups, R1b, J, and E3b. While R1b, accounting for more than half of the lineages in any of the Portuguese sub‐populations, is a characteristic marker of many different West European populations, haplogroups J and E3b consist of lineages that are typical of the circum‐Mediterranean region or even East Africa. The highly diverse haplogroup E3b in Portuguese likely combines sub‐clades of distinct origins. The present composition of the Y chromosomes in Portugal in this haplogroup likely reflects a pre‐Arab component shared with North African populations or testifies, at least in part, to the influence of Sephardic Jews. In contrast to the marginally low sub‐Saharan African Y chromosome component in Portuguese, such lineages have been detected at a moderately high frequency in our previous survey of mtDNA from the same samples, indicating the presence of sex‐related gene flow, most likely mediated by the Atlantic slave trade.
G Protein β3 Subunit Gene Variants and Essential Hypertension in the Northern Chinese Han Population
Authors: Li Biao , Ge Dongliang , Wang Yuelan , Zhao Weiyan , Zhou Xiaoyang , Gu Dongfeng , Chen Runsheng
Published: July 2005

Recently a novel C825T polymorphism in the G protein β3 subunit gene was identified that showed an association with hypertension in a German population; the results of studies in other populations have been inconsistent. To examine the contribution of GNB3 polymorphisms to the development of hypertension in the northern Chinese Han population, we conducted a case‐control study consisting of 501 hypertensive cases and 503 controls using the G(‐350)A, C825T and C1429T polymorphisms. Genotypes of samples were determined by PCR and restriction digestion. Single locus analysis showed a significant association between G(‐350)A and hypertension (P = 0.01) but no association for C825T or C1429T. The three polymorphisms were in tight linkage disequilibrium (D′=−1 for G(‐350)A‐C825T, D′= 0.92 for C825T‐C1429T) and a total of 7 haplotypes were observed in the entire population. Haplotype A‐C‐C was found to be significantly related to hypertension (P = 0.032) and A‐C‐C carriers had a more than two‐fold higher risk of hypertension than non‐carriers, after adjustment for BMI and glucose. In conclusion, our study suggests that G(‐350)A is a potential functional polymorphism that may be related to hypertension, whereas the C825T and C1429T polymorphisms are not associated with hypertension in the northern Chinese Han population.
Nail Patella Syndrome Revisited: 50 Years After Linkage
Authors: McIntosh I. , Dunston J. A. , Liu L. , Hoover‐Fong J. E. , Sweeney E.
Published: July 2005

Nail Patella Syndrome (NPS; OMIM #161200) is a pleiotropic condition, with a classical clinical tetrad of involvement of the nails, knees, elbows and the presence of iliac horns. Kidney disease and glaucoma are now recognised as part of the syndrome. Fifty years ago, James Renwick chose NPS to develop methods of linkage analysis in humans and revealed the third linkage group identified in man – that between NPS and the ABO blood group loci. After a fallow period of some forty years, the gene mutated in NPS has been identified (LMX1B) and the condition serves as a model for understanding the complex relationships between disease loci, modifier genes and the resultant clinical phenotype.
Ultraviolet A exposure might increase metastasis of mouse melanoma: a pilot study
Authors: Pastila Riikka , Leszczynski Dariusz
Published: July 2005

Background: The major sources of long‐wave ultraviolet A radiation (UVA; 320–400 nm) exposure are extensive sunbathing and tanning in solaria. While the carcinogenic effects of mid‐wave ultraviolet B radiation (UVB; 280–320 nm) are well recognized, the potentially hazardous effects of UVA are less understood. Several studies have shown that a variety of physiological processes in the cell are modified by UVA exposure, some of which might be involved in the regulation of tumor metastasis. In this study we suggest that UVA radiation could lead to the increase of metastatic capability of melanoma cells in mice.

Method/result: A pilot in vivo study was executed using C57BL/6 mice and syngeneic B16 melanoma cell lines. Mice were intravenously (i.v.) injected with either B16‐F1 or B16‐F10 melanoma cells into the tail vein and then immediately exposed to UVA. Fourteen days after melanoma injection, lungs were collected and the quantity and quality of metastases were determined under a dissecting microscope. As an outcome of the pilot study we observed that i.v. injected melanoma cells formed more lung metastases in the UVA‐exposed mice in comparison with the control mice.

Conclusion: This result suggests that the UVA exposure of mice, with melanoma cells present in blood circulation, increases the formation of melanoma metastases in lungs. Further studies should determine whether a similar pro‐metastatic effect, as observed in mice, could occur in humans and whether other than melanoma tumors might be susceptible.
The effects of heating and cooling on ultraviolet radiation‐induced erythema and pigmentation in human skin
Authors: Youn Choon Shik , Kwon Oh Sang , Hwang Eun Ju , Jo Seong Jin , Lee Min Jeong , Lee Hyun Seung , Chung Jin Ho
Published: July 2005

Background/Purpose: As most biochemical systems are affected by temperature, thermal changes before or after ultraviolet (UV) irradiation could influence skin vascular blood flow changes and inflammatory responses. In this study, our aim was to investigate the influence of thermal changes on UV‐induced acute skin reactions, namely, erythema and pigmentation.

Methods: Our volunteers consisted of 10 males, with ages ranging from 22 to 24 years and with Fitzpatrick's skin type III or IV. Skin temperatures were changed with a 45°C heating pad or by ice pack application before or after UV irradiation (control, 1 minimal erythema dose (MED), 2 MED) and then changes in erythema and pigmentation were measured by a Minolta Spectrophotometer CM‐2002.

Results: The present study demonstrates that both heating and cooling increase skin erythema and reduce pigmentation, and that the timing of heating and cooling influences the UV‐induced skin reaction. Pre‐heating and post‐cooling groups showed more UV‐induced erythema than the post‐heating and pre‐cooling groups, respectively.

Conclusion: Our results indicate that alteration of skin surface temperature could modulate UV‐induced erythema and pigmentation responses.
Biophysical, histological and biochemical changes after non‐ablative treatments with the 595 and 1320 nm lasers: a comparative study
Authors: Dang Yongyan , Ren Qiushi , Hoecker Sabine , Liu Huaxu , Ma Jingbo , Zhang Jinsheng
Published: July 2005

Background/Purpose: The objective was to compare the efficiencies of the 595 nm pulsed dye and the 1320 nm Nd : YAG laser non‐ablative rejuvenation.

Methods: KM mice were irradiated with the 595 nm pulsed dye and the 1320 nm Nd : YAG lasers. Histological changes were evaluated immediately, 1, 7, 21, 30 and 60 days after the two laser treatments. Skin hydration and hydroxyproline content were measured to quantify the degree of improvement of the skin's water‐holding capacity and the rate of hydroxyproline synthesis.

Results: Although not statistically significant, the 1320 nm Nd : YAG laser treatment induced 9.7% greater improvement of skin hydration than the 595 nm laser while the 595 nm pulsed dye laser treatment led to a thicker dermis and 8.7% greater increase of hydroxyproline than the 1320 nm laser. More than 50% increase of collagen type I was observed in 75% of 595 nm laser‐treated sites and 42% of 1320 nm laser‐treated sites, and more than 25% increase of collagen type III was observed in 75% of 595 nm laser‐treated sites and 50% of 1320 nm laser‐treated sites. The 595 nm laser treatment was better in increasing the amount of collagen fibers, especially collagen type I (P<0.05).

Conclusion: Our results demonstrated that the 595 nm laser appeared to be more effective in increasing new collagen formation, while the 1320 nm laser was superior to the 595 nm laser in improving the skin's water‐holding capacity.
Soluble tumor necrosis factor α receptor type 1 in psoriasis patients treated with narrowband ultraviolet B
Authors: Serwin Agnieszka Beata , Sokolowska Marianna , Chodynicka Bozena
Published: July 2005

Purpose: The purpose of this study was to examine the influence of narrowband ultraviolet (NB‐UVB) therapy on the serum concentration of soluble tumor necrosis factor receptor type 1 (sTNF‐R1) in psoriasis patients.

Methods: Twenty‐seven patients received NB‐UVB therapy three to five times a week for 4 weeks. The assessment of skin lesions using psoriasis area and severity index (PASI) and serum concentration of sTNF‐R1 was performed at the baseline, at 2, 4 and 4 weeks after treatment cessation. The sera of healthy subject were used as controls.

Results: The baseline PASI was 13.56±5.71, sTNF‐R1 concentration was 1.89±0.43 ng/ml in patients and 1.48±0.30 ng/ml in controls (P<0.05). The baseline PASI correlated to sTNF‐R1 (r=0.52, P<0.05). The decline in concentrations of sTNF‐R1 paralleled the decline of PASI achieved during therapy but still exceeded control values.

Conclusion: The results of the study confirm the role of sTNF‐R1 as a marker of psoriasis severity and efficacy of treatment. They also suggest that NB‐UVB influences the serum level of sTNF‐R1.
Changes in the awareness of oral health among new students newly enrolled at the University of Tokyo over the past 15 years
Authors: Hikiji H , Koshikiya N , Fujihara H , Hatano N , Matsuzaki M , Matsuzaki A , Ohki M , Susami T , Takato T , Toyo‐oka T
Published: July 2005

Objective:  The aim of this study was to examine changes in awareness of oral health among Japanese university students.

Methods:  Between 1990 and 2004, a total of 51 650 students newly enrolled at the University of Tokyo responded to an annual written questionnaire on oral health.

Results:  (i) Approximately 60% of the students brushed their teeth twice a day. Female students brushed more frequently than male students. (ii) The percentage of students who brushed for 2–3 min per time decreased, while the percentage who brushed four or more minutes increased. (iii) The number of students who had learned how to brush properly increased. This trend was particularly clear‐cut among male students, although the proportion of female students who had learned to brush properly remained higher than that of male students. (iv) The percentage of female students who sought treatment for malocclusion was higher than that of male students. The percentage of students who underwent orthodontic treatment increased from 11.6 to 19.7%. The percentage of female students who received orthodontic treatment was approximately twofold that of male students. (v) The percentage of students who had temporomandibular disorders was 0.7% in males and 1.5% in females. (vi) More than 40% of the students had periodontal diseases, with a higher prevalence among male students than female students. (vii) Approximately 20% of the students wanted to consult our service centre.

Conclusions:  The awareness of oral health among new undergraduates at the University of Tokyo has improved over the past 15 years.
Use of miswak versus toothbrushes: oral health beliefs and behaviours among a sample of Jordanian adults
Authors: Tubaishat RS , Darby ML , Bauman DB , Box CE
Published: July 2005

Objective:  This descriptive survey aimed at determining the perceived relationship among miswak, the toothbrush, and toothbrush‐plus‐miswak usage on oral health beliefs and behaviours of Jordanian adults, 18–60 years old, seeking dental care in the city of Irbid, northern Jordan.

Methods:  Patients (n = 138) voluntarily completed a self‐designed questionnaire prior to their dental appointments at public and private clinics.

Results:  Overall, the level of oral health knowledge was low; of 71 people who attempted to define dental plaque, only 26% knew the meaning of dental plaque. While 12% have never been to a dentist, and 12% visit the dentist on a regular basis, the majority (63.2%) of the respondents reported that they visit the dentist only when they have pain. The majority (72%) use the toothbrush, 20.5% use the toothbrush‐plus‐miswak and only 3% use miswak alone. Toothbrush users believe that using the toothbrush‐plus‐miswak is most effective in reducing mouth debris (χ2 = 32.069, d.f. = 16, P = 0.01); and level of education is significantly associated with the type of oral cleaning device used (χ2 = 25.817, d.f. = 12, P = 0.05). There was no significant difference between toothbrush users and toothbrush‐plus‐miswak users in terms of how they perceive their oral health status. About 19% of the study participants use dental floss, 60.9% use mouth rinses and 8.3% use inter‐dental brushes. Educated people (baccalaureate or associate degrees) tended to use toothbrushes and toothbrush‐plus‐miswak. The toothbrush‐plus‐miswak users are most likely to spend 1–2 min each day cleaning their teeth (χ2 = 34.9, d.f. = 20, P = 0.02) than those using other devices. Respondents who use the toothbrush are most likely to visit the dentist when they have pain (χ2 = 34.02, d.f. = 12, P = 0.00) than those using other devices.

Conclusion:  The oral health awareness level among Jordanian adults is poor and needs to be improved. Evidence‐based and community‐based dental health education and a philosophical change from disease‐oriented and pain management care to primary preventive care are highly recommended for the Jordanian population.
Temporal Changes in the Vertical Distribution of Flow and Chloride in Deep Wells
Authors: Izbicki John A. , Christensen Allen H. , Newhouse Mark W. , Smith Gregory A. , Hanson Randall T.
Published: July 2005

The combination of flowmeter and depth‐dependent water‐quality data was used to evaluate the quantity and source of high‐chloride water yielded from different depths to eight production wells in the Pleasant Valley area of southern California. The wells were screened from 117 to 437 m below land surface, and in most cases, flow from the aquifer into the wells was not uniformly distributed throughout the well screen. Wells having as little as 6 m of screen in the overlying upper aquifer system yielded as much as 50% of their water from the upper system during drought periods, while the deeper parts of the well screens yielded 15% or less of the total yield of the wells. Mixing of water within wells during pumping degraded higher‐quality water with poorer‐quality water from deeper depths, and in some cases with poorer‐quality water from the overlying upper aquifer system. Changes in the mixture of water within a well, resulting from changes in the distribution of flow into the well, changed the quality of water from the surface discharge of wells over time. The combination of flowmeter and depth‐dependent water quality data yielded information about sources of high‐chloride water to wells that was not available on the basis of samples collected from nearby observation wells. Changing well design to eliminate small quantities of poor‐quality water from deeper parts of the well may improve the quality of water from some wells without greatly reducing well yield.
Carbon Biogeochemistry of Ground Water, Guiyang, Southwest China
Authors: Li Si‐Liang , Liu Cong‐Qiang , Tao Fa‐Xiang , Lang Yun‐Chao , Han Gui‐Lin
Published: July 2005

Variations in the concentrations and isotopic compositions (δ13CDIC) of dissolved inorganic carbon (DIC) reflect contamination and biogeochemical cycling of the carbon in ground water. In order to understand contamination and biogeochemical cycling of DIC, we carried out research on the geochemistry of ground water of Guiyang, the capital city of Guizhou Province, China. Results show that ground water is mainly characterized by SO4·HCO3‐Ca·Mg and HCO3‐Ca·Mg chemical compositions. The hydrochemical characteristics of these types of water are mainly controlled by lithology of the aquifers. HCO3− is the dominant species of DIC in ground water and has lower concentrations and more negative values of δ13CDIC in the high‐flow (summer monsoon) season, as compared to the low‐flow season. This indicates that DIC is relatively enriched in carbon of biological origin in the high‐flow season as compared to the low‐flow season and that biological activities are the predominant control on shifts of stable carbon isotope values. The evidence that the δ13CDIC values of ground water decrease with increasing concentrations of anthropogenic species shows that the carbon isotopic composition of DIC can be a useful tracer of contamination, in addition to biogeochemical cycling of inorganic carbon in ground water. Results from this study show that ground water is impacted by significant levels of contamination from human activities, especially in the urban areas, as well as the northeast and west suburbs, in Guiyang city, southwest China.
Implications of Ground Water Chemistry and Flow Patterns for Earthquake Studies
Authors: Guangcai Wang , Zuochen Zhang , Min Wang , Cravotta Charles A. , Chenglong Liu
Published: July 2005

Ground water can facilitate earthquake development and respond physically and chemically to tectonism. Thus, an understanding of ground water circulation in seismically active regions is important for earthquake prediction. To investigate the roles of ground water in the development and prediction of earthquakes, geological and hydrogeological monitoring was conducted in a seismogenic area in the Yanhuai Basin, China. This study used isotopic and hydrogeochemical methods to characterize ground water samples from six hot springs and two cold springs. The hydrochemical data and associated geological and geophysical data were used to identify possible relations between ground water circulation and seismically active structural features. The data for δ18O, δD, tritium, and14C indicate ground water from hot springs is of meteoric origin with subsurface residence times of 50 to 30,320 years. The reservoir temperature and circulation depths of the hot ground water are 57°C to 160°C and 1600 to 5000 m, respectively, as estimated by quartz and chalcedony geothermometers and the geothermal gradient. Various possible origins of noble gases dissolved in the ground water also were evaluated, indicating mantle and deep crust sources consistent with tectonically active segments. A hard intercalated stratum, where small to moderate earthquakes frequently originate, is present between a deep (10 to 20 km), high–electrical conductivity layer and the zone of active ground water circulation. The ground water anomalies are closely related to the structural peculiarity of each monitoring point. These results could have implications for ground water and seismic studies in other seismogenic areas.
Isotopes and Sustainability of Ground Water Resources, North China Plain
Authors: Zongyu Chen , Zhenlong Nie , Zhaoji Zhang , Jixiang Qi , Yunju Nan
Published: July 2005

Ground water in deep confined aquifers is one of the major water resources for agricultural, industrial, and domestic uses in the North China Plain. Detailed information on ground water age and recharge is vital for the proper management of these water resources, and to this end, we used carbon 14 of dissolved inorganic carbon and tritium in water to measure the age and determine the recharge areas of ground water in the North China Plain. These isotopic data suggest that most ground water in the piedmont part of the North China Plain is <40 years old and is recharged locally. In contrast, ground water in the central and littoral portions of the North China Plain is 10,000 to 25,000 years old. The δ18O (δD) values of this ground water are 1.7‰ (11‰) less than that in the piedmont plain ground water and possibly reflect water recharged during a cooler climate during the last glaciation. The temperature of this recharge, based on δ18O values, ranges from 3.7°C to 8.4°C, compared to 12°C to 13°C of modern recharge water. The isotopic data set combined indicates that ground water in the central and littoral part of the North China Plain is being mined under non–steady state conditions.
Analysis of Recharge‐Induced Geochemical Change in a Contaminated Aquifer
Authors: McGuire Jennifer T. , Long David T. , Hyndman David W.
Published: July 2005

Recharge events that deliver electron acceptors such as O2, NO3, SO4, and Fe3+ to anaerobic, contaminated aquifers are likely important for natural attenuation processes. However, the specific influence of recharge on (bio)geochemical processes in ground water systems is not well understood. The impact of a moderate‐sized recharge event on ground water chemistry was evaluated at a shallow, sandy aquifer contaminated with waste fuels and chlorinated solvents. Multivariate statistical analyses coupled with three‐dimensional visualization were used to analyze ground water chemistry data (including redox indicators, major ions, and physical parameters) to reveal associations between chemical parameters and to infer processes within the ground water plume. Factor analysis indicated that dominant chemical associations and their interpreted processes (anaerobic and aerobic microbial processes, mineral precipitation/dissolution, and temperature effects) did not change significantly after the spring recharge event of 2000. However, the relative importance of each of these processes within the plume changed. After the recharge event, the overall importance of aerobic processes increased from the fourth to the second most important factor, representing the variability within the data set. The anaerobic signatures became more complex, suggesting that zones with multiple terminal electron–accepting processes (TEAPs) likely occur in the same water mass. Three‐dimensional visualization of well clusters showed that water samples with similar chemical associations occurred in distinct water masses within the aquifer. Water mass distinctions were not based on dominant TEAPs, suggesting that the recharge effects on TEAPs occurred primarily at the interface between infiltrating recharge water and the aquifer.
Heat as a Tracer to Estimate Dissolved Organic Carbon Flux from a Restored Wetland
Authors: Burow Karen R. , Constantz Jim , Fujii Roger
Published: July 2005

Heat was used as a natural tracer to characterize shallow ground water flow beneath a complex wetland system. Hydrogeologic data were combined with measured vertical temperature profiles to constrain a series of two‐dimensional, transient simulations of ground water flow and heat transport using the model code SUTRA (Voss 1990). The measured seasonal temperature signal reached depths of 2.7 m beneath the pond. Hydraulic conductivity was varied in each of the layers in the model in a systematic manual calibration of the two‐dimensional model to obtain the best fit to the measured temperature and hydraulic head. Results of a series of representative best‐fit simulations represent a range in hydraulic conductivity values that had the best agreement between simulated and observed temperatures and that resulted in simulated pond seepage values within 1 order of magnitude of pond seepage estimated from the water budget. Resulting estimates of ground water discharge to an adjacent agricultural drainage ditch were used to estimate potential dissolved organic carbon (DOC) loads resulting from the restored wetland. Estimated DOC loads ranged from 45 to 1340 g C/(m2 year), which is higher than estimated DOC loads from surface water. In spite of the complexity in characterizing ground water flow in peat soils, using heat as a tracer provided a constrained estimate of subsurface flow from the pond to the agricultural drainage ditch.
An Analytical Solution for Ground Water Transit Time through Unconfined Aquifers
Authors: Chesnaux R. , Molson J.W. , Chapuis R.P.
Published: July 2005

An exact, closed‐form analytical solution is developed for calculating ground water transit times within Dupuit‐type flow systems. The solution applies to steady‐state, saturated flow through an unconfined, horizontal aquifer recharged by surface infiltration and discharging to a downgradient fixed‐head boundary. The upgradient boundary can represent, using the same equation, a no‐flow boundary or a fixed head. The approach is unique for calculating travel times because it makes no a priori assumptions regarding the limit of the water table rise with respect to the minimum saturated aquifer thickness. The computed travel times are verified against a numerical model, and examples are provided, which show that the predicted travel times can be on the order of nine times longer relative to existing analytical solutions.
Unconfined Linear Flow to a Horizontal Well
Authors: Wojciech Kawecki M. , Al‐Subaikhy Hassan N.
Published: July 2005

The validity of a previously proposed but untested modification to equations for flow to a horizontal well is assessed using a specially developed finite‐difference model. This modification extends confined flow equations to allow the head in the well and the saturated depth at the well to be estimated in unconfined conditions. The study is limited to the case of two‐dimensional flow with no flow in the direction parallel to the line of the well. The results show that the modified equations for both a finite unconfined aquifer and, by inference, an infinite unconfined aquifer are adequately accurate for practical application.
High‐Permeability Layers for Remediation of Ground Water; Go Wide, Not Deep
Authors: Robertson W.D. , Yeung N. , VanDriel P.W. , Lombardo P.S.
Published: July 2005

A nitrate‐reactive porous media layer comprising wood particles with very high hydraulic conductivity (K∼ 1 cm/s) was used to successfully treat nitrate in a shallow sand‐and‐gravel aquifer in southern Ontario. Nitrate concentrations of 1.3 to 14 mg/L as N in the aquifer were attenuated to <0.5 mg/L as N in the reactive layer. Borehole dilution testing indicated that ground water velocities in the reactive layer, although variable, averaged five times higher than in the surrounding aquifer, suggesting that the layer was capturing ground water flow from deeper in the aquifer. The use of high‐K reactive media opens up the possibility of installing permeable reactive barriers as horizontal layers in the shallow water table zone that do not necessarily have to penetrate the full depth of a contaminant plume to be effective. Model simulations show that the depth of capture of a high‐K layer increases as the layer width in the direction of flow increases. Shallower emplacement could decrease barrier costs at some sites.
The Role of Ground Water in Arid/Semiarid Ecosystems, Northwest China
Authors: Cui Yali , Shao Jingli
Published: July 2005

Ground water plays an important role in water supply and the ecology of arid to semiarid areas such as Northwest China, where the landscape is fragile due to frequent drought in the past few decades. This paper discusses the role of ground water in these ecosystems, including the effect of condensation water and water table depth on the growth of plants and degree of soil salinity. The paper also discusses the controlling process for land desertification and soil salinization in Northwest China. Water table depth is a key factor controlling the water balance, ground water flow, and salt transport in the vadose zone. The suitable water table depth for vegetation growth, which can prevent land desertification and soil salinization, is within a range of 2 to 4 m; the optimal depth is ∼3 m. As examples, changes in ecosystems owing to water resources development in Tarim and Manas basins, Xinjiang, China, are discussed.
Model Parameters for Simulating Fate and Transport of On‐Site Wastewater Nutrients
Authors: McCray John E. , Kirkland Shiloh L. , Siegrist Robert L. , Thyne Geoffrey D.
Published: July 2005

This paper presents a critical review of model‐input parameters for transport of on‐site wastewater treatment system (OWS) pollutants. Approximately 25% of the U.S. population relies on soil‐based OWS for effective treatment and protection of public health and environmental quality. Mathematical models are useful tools for understanding and predicting the transport and fate of wastewater pollutants and for addressing water‐budget issues related to wastewater reclamation from site to watershed scales. However, input parameters for models that simulate fate and transport of OWS pollutants are not readily obtained. The purpose of this analysis is to illustrate an objective, statistically supported method for choosing model‐input parameters related to nitrogen (N) and phosphorus (P). Data were gathered from existing studies reported in the literature. Cumulative frequency distributions (CFDs) are provided for OWS effluent concentrations of N and P, nitrification and denitrification rates, and linear sorption isotherm constants for P. When CFDs are not presented, ranges and median values are provided. Median values for model‐input parameters are as follows: total N concentration (44 mg/L), nitrate‐N (0.2 mg/L), ammonium (60 mg/L), phosphate‐P (9 mg/L), organic N (14 mg/L), zero‐order nitrification rate (264 mg/L/d), first‐order nitrification (2.9/d), first‐order dentrification (0.025/d), maximum soil capacity for P uptake (237 mg/kg), linear sorption isotherm constant for P (15.1 L/kg), and OWS effluent flow rates (260 L/person/d).
Vertical Cross Contamination of Trichloroethylene in a Borehole in Fractured Sandstone
Authors: Sterling S.N. , Parker B.L. , Cherry J.A. , Williams J.H. , Lane J.W. , Haeni F.P.
Published: July 2005

Boreholes drilled through contaminated zones in fractured rock create the potential for vertical movement of contaminated ground water between fractures. The usual assumption is that purging eliminates cross contamination; however, the results of a field study conducted in a trichloroethylene (TCE) plume in fractured sandstone with a mean matrix porosity of 13% demonstrates that matrix‐diffusion effects can be strong and persistent. A deep borehole was drilled to 110 m below ground surface (mbgs) near a shallow bedrock well containing high TCE concentrations. The borehole was cored continuously to collect closely spaced samples of rock for analysis of TCE concentrations. Geophysical logging and flowmetering were conducted in the open borehole, and a removable multilevel monitoring system was installed to provide hydraulic‐head and ground water samples from discrete fracture zones. The borehole was later reamed to complete a well screened from 89 to 100 mbgs; persistent TCE concentrations at this depth ranged from 2100 to 33,000 μg/L. Rock‐core analyses, combined with the other types of borehole information, show that nearly all of this deep contamination was due to the lingering effects of the downward flow of dissolved TCE from shallower depths during the few days of open‐hole conditions that existed prior to installation of the multilevel system. This study demonstrates that transfer of contaminant mass to the matrix by diffusion can cause severe cross contamination effects in sedimentary rocks, but these effects generally are not identified from information normally obtained in fractured‐rock investigations, resulting in potential misinterpretation of site conditions.
MTBE and Gasoline Hydrocarbons in Ground Water of the United States
Authors: Moran Michael J. , Zogorski John S. , Squillace Paul J.
Published: July 2005

The occurrence of methyl tert‐butyl ether (MTBE) and gasoline hydrocarbons was examined in three types of studies of ground water conducted by the U.S. Geological Survey: major aquifer surveys, urban land‐use studies, and agricultural land‐use studies. The detection frequency of MTBE was dependent on the study type, with the highest detection frequency in urban land‐use studies. Only 13 ground water samples from all study types, or 0.3%, had concentrations of MTBE that exceeded the lower limit of the U.S. EPA's Drinking‐Water Advisory. The detection frequency of MTBE was highest in monitoring wells located in urban areas and in public supply wells. The detection frequency of any gasoline hydrocarbon also was dependent on study type and generally was less than the detection frequency of MTBE. The probability of detecting MTBE in ground water was strongly associated with population density, use of MTBE in gasoline, and recharge. Ground water in areas with high population density, in areas where MTBE is used as a gasoline oxygenate, and in areas with high recharge rates had a greater probability of MTBE occurrence. Also, ground water from public supply wells and shallow ground water underlying urban land‐use areas had a greater probability of MTBE occurrence compared to ground water from domestic wells and ground water underlying rural land‐use areas. The probability of detecting MTBE in ground water was weakly associated with the density of leaking underground storage tanks, soil permeability, and aquifer consolidation, and only concentrations of MTBE >0.5 μg/L were associated with dissolved oxygen.
NMR OBSERVATION OF THE SPIN-LATTICE AND SPIN-SPIN RELAXATION IN SOME POLIBUTADIENES WITH DIFFERENT VINYL CONTENTS
Authors: TODICA M.
Published: July 2005

Some polybutadienes with different vinyl contents were observed by NMR methods in order to disclose the influence of the microstructure of the polymeric chains on the relaxation of the longitudinal and transverse magnetization. The relaxation process is correlated with the dynamic properties of the polymeric chains. The residual dipolar interaction determined by the rigidity of the polymeric chains is observed by the pseudo-solid echo method and is associated with the vinyl contents of the samples.
STRUCTURAL PHASE DIAGRAM FOR THE THERMAL CONTROLLED DISTORTION BY Gd IONS IN THE (Nd1-yGdy)1.85Ce0.15CuO4 HTS SYSTEM
Authors: PELSHENKE C. , POP A. V. , COZAR O.
Published: July 2005

The influence of partial substitution of Nd by Gd on the temperature dependence of the lattice parameters of the optimal doped Nd 1.85 Ce 0.15 CuO 4n-type superconductor (maximum value of Tc) was studied by using X-ray diffraction measurements function of temperature.

The transition from the structural normal phase (I4/mmm) to the distortion phase (Acam) was evidenced above y = 0.65 Gd substitution level in ( Nd 1-y Gd y)1.85 Ce 0.15 CuO 4. The structural phase transition temperature TI-A from undistorted phase to the distorted phase changes function of Gd concentration.

The structural phase diagram for thermal controlled distortion by Gd ions, TI-A = f(y) was obtained, and compared by the superconducting phase diagram Tc(y).
REAL-SPACE RENORMALIZATION-GROUP APPROACH TO THE INTEGER QUANTUM HALL EFFECT
Authors: CAIN PHILIPP , RÖMER RUDOLF A.
Published: July 2005

We review recent results based on an application of the real-space renormalization group (RG) approach to a network model for the integer quantum Hall (QH) transition. We demonstrate that this RG approach reproduces the critical distribution of the power transmission coefficients, i.e., two-terminal conductances, Pc(G), with very high accuracy. The RG flow of P(G) at energies away from the transition yields a value of the critical exponent ν that agrees with most accurate large-size lattice simulations. A description of how to obtain other relevant transport coefficients such as RLand RHis given. From the non-trivial fixed point of the RG flow we extract the critical level-spacing distribution (LSD). This distribution is close, but distinctively different from the earlier large-scale simulations. We find that the LSD obeys scaling behavior around the QH transition with ν = 2.37±0.02. Away from the transition it crosses over towards the Poisson distribution. We next investigate the plateau-to-insulator transition at strong magnetic fields. For a fully quantum coherent situation, we find a quantized Hall insulator with RH≈h/e2up to RL~20h/e2when interpreting the results in terms of most probable value of the distribution function P(RH). Upon further increasing RL→∞, the Hall insulator with diverging Hall resistance [Formula: see text] is seen. The crossover between these two regimes depends on the precise nature of the averaging procedure for the distributions P(RL) and P(RH). We also study the effect of long-ranged inhomogeneities on the critical properties of the QH transition. Inhomogeneities are modeled by a smooth random potential with a correlator which falls off with distance as a power law r-α. Similar to the classical percolation, we observe an enhancement of ν with decreasing α. These results exemplify the surprising fact that a small RG unit, containing only five nodes, accurately captures most of the correlations responsible for the localization-delocalization transition.
MAGNETORESISTANCE IN METALS WITH EMBEDDED MAGNETIC NANOCLUSTERS
Authors: TSYPLYATYEV O. , FAL'KO VLADIMIR I.
Published: July 2005

We propose a kinetic theory of transport in metals embedded with ferromagnetic nanoclusters, predicting a quadratic low-field magnetoresistance in an ensemble of clusters in thermodynamic equilibrium. We show that this effect is strongest when all the clusters have the same intrinsic easy-axis anisotropy.
TRAVELLING WAVE SOLUTIONS TO THE COUPLED DISCRETE NONLINEAR SCHRÖDINGER EQUATIONS
Authors: DAI CHAO-QING , ZHANG JIE-FANG
Published: July 2005

In this paper, we have utilized the extended Jacobian elliptic function approach to construct seven families of new Jacobian elliptic function solutions for the coupled discrete nonlinear Schrödinger equations. When the modulus m → 1 or 0, some of these obtained solutions degenerate to the soliton solutions (the moving bright-bright and dark-dark solitons), the solitonic solutions and the trigonometric function solutions. This integrable model possesses the moving solitons because there is no PN barrier to block their motion in the lattice. We also find that some solutions in differential-difference equations (DDEs) are essentially identical to the continuous cases, while some solutions such as sec-type and tan-type in differential-difference models present different properties.
INCOMMENSURATE SPIN DYNAMICS IN UNDERDOPED CUPRATE PEROVSKITES
Authors: SHERMAN A. , SCHREIBER M.
Published: July 2005

The incommensurate magnetic response observed in normal-state cuprate perovskites is interpreted based on the projection operator formalism and the t–J model of Cu-O planes. In agreement with experiment the calculated dispersion of maxima in the susceptibility has the shape of two parabolas with upward and downward branches which converge at the antiferromagnetic wave vector. The maxima are located at the momenta (½, ½ ± δ), (½ ± δ, ½) and at (½ ± δ, ½ ± δ), (½ ± δ, ½ ∓ δ) in the lower and upper parabolas, respectively. The upper parabola reflects the dispersion of magnetic excitations of the localized Cu spins, while the lower parabola arises due to a dip in the spin-excitation damping at the antiferromagnetic wave vector. For moderate doping this dip stems from the weakness of the interaction between the spin excitations and holes near the hot spots. The frequency dependence of the susceptibility is shown to depend strongly on the hole bandwidth and damping and varies from the shape observed in YBa 2 Cu 3 O 7-y to that inherent in La 2-x Sr x CuO 4.
A COMPARISON OF THE EFFECTIVENESS OF USING THE MESHLESS METHOD AND THE FINITE DIFFERENCE METHOD IN GEOSTATISTICAL ANALYSIS OF TRANSPORT MODELING
Authors: VRANKAR LEOPOLD , TURK GORAN , RUNOVC FRANC
Published: July 2005

Disposal of radioactive waste in geological formations is a great concern with regards to nuclear safety. The general reliability and accuracy of transport modeling depends predominantly on input data such as hydraulic conductivity, water velocity, radioactive inventory, and hydrodynamic dispersion. The most important input data are obtained from field measurements, but they are not always available. One way to study the spatial variability of hydraulic conductivity is geostatistics. The numerical solution of partial differential equations (PDEs) has usually been obtained by finite difference methods (FDM), finite element methods (FEM), or finite volume methods (FVM). These methods require a mesh to support the localized approximations. The multiquadric (MQ) radial basis function method is a recent meshless collocation method with global basis functions. Solving PDEs using radial basis function (RBF) collocations is an attractive alternative to these traditional methods because no tedious mesh generation is required. We compare the meshless method, which uses radial basis functions, with the traditional finite difference scheme. In our case we determine the average and standard deviation of radionuclide concentration with regard to spatial variability of hydraulic conductivity that was modeled by a geostatistical approach.
A REDUCTION OF THE BOLTZMANN-PEIERLS EQUATION
Authors: KUNIK MATTHIAS , QAMAR SHAMSUL , WARNECKE GERALD
Published: July 2005

This paper deals with the solutions of initial value problems of the Boltzmann-Peierls equation (BPE). This integro-differential equation describes the evolution of heat in crystalline solids at very low temperatures. The BPE describes the evolution of the phase density of a phonon gas. The corresponding entropy density is given by the entropy density of a Bose-gas. We derive a reduced three-dimensional kinetic equation which has a much simpler structure than the original BPE. By using special coordinates in the one-dimensional case, we can perform a further reduction of the kinetic equation. By assuming one-dimensionality on the initial phase density one can show that this property is preserved for all later times. We derive kinetic schemes for the kinetic equation as well as for the derived moment systems. Several numerical test cases are presented to validate the theory.
AN AUGMENTED PROJECTION METHOD FOR THE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS IN ARBITRARY DOMAINS
Authors: KIM JUNSEOK
Published: July 2005

A Cartesian grid method for computing flows with complex immersed, stationary and moving boundaries is presented in this paper. We introduce an augmented projection method for the numerical solution of the incompressible Navier-Stokes equations in arbitrary domains. In a projection method an intermediate velocity field is calculated from the momentum equations, which is then projected onto the space of divergence-free vector fields. In the proposed augmented projection method, we add one more step, which effectively eliminates spurious velocity field caused by complex immersed moving boundaries. The methodology is validated by comparing it with analytic, previous numerical and experimental results.