bluuebunny/crossref_metadata_2025 huggingface dataset:
Plate‐boundary strain partitioning along the sinistral collision suture of the Philippine and Eurasian plates: Analysis of geodetic data and geological observation in southeastern Taiwan
Authors: Lee Jian‐Cheng , Angelier Jacques , Chu Hao‐Tsu , Yu Shui‐Beih , Hu Jyr‐Ching
Published: February 2004

Crustal deformation and strain partitioning of oblique convergence between the Philippine Sea plate and the Eurasian plate in the southern Longitudinal Valley of eastern Taiwan were characterized, based on geodetic analysis of trilateration network and geological field investigation. The Longitudinal Valley fault, one of the most active faults on Taiwan, branches into two individual faults in the southern Longitudinal Valley. These two active faults bound the Plio‐Pleistocene Pinanshan Conglomerate massif between the Coastal Range (the Luzon island arc belonging to the Philippine Sea plate) and the Central Range (the metamorphic basement of the Eurasian plate). A geodetic trilateration network near the southern end of the valley shows a stable rate of the annual length changes during 1983–1990. The strain tensors for polygonal regions (including triangular regions) of the Taitung trilateration network reveal that there are two distinct zones of deformation: a zone of shortening (thrusting) between the Pinanshan massif and the Central Range on the west and a strike‐slip movement between the Pinanshan massif and the Coastal Range on the east. The analysis of a discontinuity model consisting of three rigid blocks separated by two discontinuities has been carried out. The results show that the deformation in this region can be characterized by two major faults. A reverse fault is located between the Plio‐Pleistocene Pinanshan massif and the metamorphic basement of the Central Range, with a shortening rate of about 12 mm/yr in the direction N280°E. A strike‐slip fault is located principally along the river between the Pinanshan massif and island arc system of the Coastal Range with a purely strike‐slip component of about 22 mm/yr in the direction N353°E. The analysis of the geodetic data further suggests that substantial deformation (probably strike slip in type) occurs within the Pinanshan massif. Geological evidence of deformation in the Plio‐Pliestocene Pinanshan Conglomerate includes regional folding, a conjugate set of strike‐slip fractures at the outcrop scale, and morphological lineaments related to fracturing, all indicating that the Pinanshan massif is being deformed within a transpressive stress regime. Regional kinematic data indicate that a significant portion of the 82 mm/yr of motion between the Eurasian plate and the Philippine Sea plate is absorbed in the southern Longitudinal Valley by the decoupling of two distinct major faults. The geometry of the oblique convergence and the rheology of the rock units (the well‐consolidated Plio‐Pleistocene conglomerate and the sheared mélange formation) play the two important roles in the partitioning of crust deformation.
Crustal structure of the Middle Urals: Results from the (ESRU) Europrobe seismic reflection profiling in the Urals experiments
Authors: Juhlin C. , Friberg M. , Echtler H. P. , Hismatulin T. , Rybalka A. , Green A. G. , Ansorge J.
Published: February 2004

As a contribution to Europrobe's seismic reflection profiling in the Urals (ESRU) project, three overlapping seismic reflection data sets were acquired in the Middle Urals. A 56 km long profile was registered over the Europe‐Asia suture, two 25 km long intersecting profiles were collected over the Urals superdeep borehole (SG4), and an 80 km long profile was recorded eastward extending east toward the West Siberian Basin. Reflections on the seismic sections delineate several major middle to late Paleozoic thrust zones in the upper crust. These thrust zones have a bivergent geometry with westerly vergence west of the Uralian orogenic axis and easterly vergence to the east. The principal terrane boundaries are the Main Uralian Thrust Fault in the west and the Trans‐Uralian Thrust Zone in the east. Normal faults are spatially associated with former thrust faults, or they crosscut them. The thrust and normal faults can be confidently correlated with surface geological features. Near‐vertical and wide‐angle seismic reflection profiling reveals thickening of the crust from about 45 km to approximately 53 km below the central axis of the Urals. East and west of the root zone, the lower crust is reflective, particularly toward the West Siberian Basin. We interpret the reflectivity of the crust below the East European Craton as pre‐Uralian, whereas that toward the West Siberian Basin is interpreted as late orogenic. Although the principal tectonic features imaged by the seismic sections are probably of Paleozoic age, a post‐Paleozoic origin for the lower crustal reflectivity in the east cannot be ruled out.
Contrasting Oligocene and Miocene thermal histories from the hanging wall and footwall of the South Tibetan detachment in the central Himalaya from 40Ar/39Ar thermochronology, Marsyandi Valley, central Nepal
Authors: Coleman Margaret E. , Hodges Kip V.
Published: February 2004

In the Marsyandi valley of central Nepal, a major strand of the South Tibetan detachment system, the 18–22 Ma Chame detachment, places epidote‐amphibolite to amphibolite facies calc‐silicate rocks and marbles of the Tibetan sedimentary sequence on amphibolite facies pelitic gneisses and calc‐silicate rocks of the Greater Himalayan sequence. Although the resulting metamorphic discontinuity is minor and sometimes cryptic, 40Ar/39Ar thermochronologic results from the area reveal that the hanging wall and footwall of the detachment had distinctive thermal histories. Hanging wall phlogopites and biotites yield cooling ages of 27.1 – 29.9 Ma, compared with footwall biotite ages of 14.1 – 16.6 Ma. U‐Pb monazite thermochronology demonstrates that the Greater Himalayan sequence experienced peak amphibolite facies conditions at approximately 22 Ma, but the 40Ar/39Ar results require hanging wall metamorphism to be an Oligocene (or older) phenomenon. These events are interpreted as representing the “Neohimalayan” and “Eohimalayan” metamorphic phases proposed by previous workers in the central Himalaya. Some of the dated hanging wall phlogopites grew synchronously with development of SW vergent macroscopic folds in the Tibetan sedimentary sequence, implying that Eohimalayan metamorphism was associated with an important phase of crustal shortening in this sector of the Himalaya. Despite the intensity of Neohimalayan metamorphism below the Chame detachment, evidence for Eohimalayan metamorphism and igneous activity is preserved in the footwall rocks of the Marsyandi drainage. Inherited approximately 35 Ma monazites of either metamorphic or igneous origin have been found in the upper Greater Himalayan sequence in this area, and one hornblende separate from the uppermost footwall yields a 40Ar/39Ar age of 30.0 ± 3.0 Ma. This hornblende date and a similar result from the same structural level in the nearby Kali Gandaki valley, if robust, suggest that the duration of the Neohimalayan event was extremely short, probably less than 1 million years and that peak temperatures in the upper part of the Greater Himalayan sequence were not substantially greater than about 900 K.
An evaluation of Jacob's Method for the interpretation of pumping tests in heterogeneous formations
Authors: Meier Peter M. , Carrera Jesús , Sánchez‐Vila Xavier
Published: February 2004

Most pumping tests are interpreted using the classical Theis assumption of large‐scale homogeneity with various corrections to account for early time behavior of drawdown curves. When drawdowns are plotted versus log time, late time data often delineate a straight line, which is consistent with Jacob's approximation of Theis' solution but may seem surprising in view of the heterogeneity of natural media. The aim of our work is to show that Jacob's method leads to a good approximation of the effective transmissivity of heterogeneous media when constrained to late time data. A review of several multiwell pumping tests demonstrates that when drawdown curves from each observation well are interpreted separately, they produce very similar transmissivity T estimates. However, the corresponding estimates for storativity span a broad range. This behavior is verified numerically for several models of formation heterogeneity. A very significant finding of the numerical investigation is that T values estimated using simulated drawdown from individual observation wells are all very close to the effective T value for parallel flow. This was observed even in nonmultiGaussian T fields, where high T zones are well connected and where the effective T is larger than the geometric average of point values. This implies that Jacob's method can be used for estimating effective T values in many, if not most, formations.
Parameterization of stream channel geometry in the distributed modeling of catchment dynamics
Authors: Orlandini Stefano , Rosso Renzo
Published: February 2004

A simple and efficient procedure for incorporating the effects of stream channel geometry in the distributed modeling of catchment dynamics is developed. At‐a‐station and downstream fluvial relationships are combined and the obtained laws of variability in space and time for water‐surface width and wetted perimeter are incorporated into a diffusion wave routing model based on the Muskingum‐Cunge method with variable parameters. The parameterization obtained is applied to the approximately 840‐km2 Sieve catchment (Central Italian Apennines) to test the possibility of estimating channel geometry parameters from cross‐section surveys and to assess the impact of dynamic variations in the channel geometry on catchment dynamics. The use of the estimated channel geometry in surface runoff routing produces a significant improvement in the flood hydrograph description at the catchment outlet with respect to less detailed network parameterizations. In addition, the results obtained from a “downstream” analysis of the velocity field indicate that the stream characteristics related to the locally varying cross‐section shape may have a strong control on flow velocities, and thus they should be monitored and synthesized for a comprehensive description of the distributed catchment dynamics.
Air bubble migration in a granular porous medium: Experimental studies
Authors: Roosevelt Sharon E. , Corapcioglu M. Yavuz
Published: February 2004

To provide insight into the mechanism of bubble migration in in situ air sparging in a coarse porous medium, the rise of air bubbles through a granular porous medium is studied through video photography enhanced with image analysis. The porous medium is simulated by a fully saturated cylindrical glass column filled with 4‐mm glass beads in random packing order. The experimental procedure for introducing and visualizing a single air bubble is discussed, and the average rise velocity as a function of the emerging bubble radius is directly measured. Compressed air is injected into the base of the column through the use of an electronically controlled solenoid valve. The resulting bubble motion is recorded by camcorder, and still frames are captured and enhanced from the videotape with an image analyzer. The vertical rise of a bubble through the porous medium displays a linear dependence on time. This is the first study to quantify the terminal velocity of an air bubble rising in a stationary porous medium. Comparison is made to experimental data on air bubbles in water and Soltrol obtained using the same video photography and image analysis techniques. Although a porous medium is sometimes represented as a bundle of capillary tubes, an air bubble rising in a granular porous medium is shown to exhibit significantly different behavior from a bubble rising in either a capillary tube or a tube with a diameter comparable to the equivalent diameter of the bubble. The effect of a bubble chain, a series of single bubbles separated vertically from each other by a few centimeters, on air bubble migration in a granular porous medium is also discussed.
Finite amplitude bed deformations in totally and partially transporting wide channel bends
Authors: Seminara G. , Solari L.
Published: February 2004

We develop an analytic approach able to predict flow and bed topography in curved cohesionless wide channels. The novel feature of the present theory, compared with previous analytic approaches, is its ability to treat bottom perturbations of finite amplitude and situations such that sediment transport does not occur within the whole cross section. The theory is presently applied to the case of constant curvature channels though it can be extended, in principle, to channels with variable curvature. Results show that the dominant mechanism controlling the establishment of bed profile is the topographic feedback of bottom deformations on the flow field, while the role of the dispersive transverse transport of longitudinal momentum and of the metrically induced transverse variations of longitudinal slope is usually relatively small. The theory extends previous linear analyses which are shown to underpredict deeping of the cross section close to the outer bank. Also, unlike linear theories, the present approach predicts a transverse slope of the bed profile increasing towards the outer bend in agreement with experimental observations. The maximum depth is found to depend on the friction coefficient Cu of the undisturbed uniform stream and on the parameter v(θu)1/2/Cu where v is curvature ratio, that is, the ratio between channel half width and radius of curvature of the centerline, while θu is the Shields stress of the undisturbed uniform stream. Comparison with experimental observations is fairly satisfactory. The shape of the cross section is then determined also for values of θu close enough to the critical values not to allow bedload transport within the whole cross section. The threshold value of θu separating the total transport from the partial transport regime is finally determined as a function of the curvature ratio v.
Generating precipitation time series using simulated annealing
Authors: Bárdossy András
Published: February 2004

Long, high time resolution precipitation time series are often needed in hydrology. In most cases available measurements are not sufficient, because of a coarse time resolution and/or because observations are taken at differing locations. Often generated time series are used. These series are usually obtained from stochastic precipitation models that reproduce properties of the observed series. The purpose of this paper is to present a different methodology, one in which precipitation series can be generated by directly using their properties. The method uses simulated annealing, based on the Metropolis‐Hastings algorithm. An objective function including all desired properties is formulated. The method generates series with the desired properties. The advantage of this formulation is that properties of the precipitation that are important for the target application can directly be incorporated. The method can also be applied for generating precipitation series in a changed climate. For this purpose, changes of the statistical properties of the series have to be assessed.
Infiltration into crusted soils
Authors: Philip J. R.
Published: February 2004

Quasi‐analytic methods are used to analyze ponded infiltration into crusted soils. The flux‐concentration method provides accurate bridging between exact small‐time similarity and large‐time traveling wave solutions. Various studies have used one or more of the following simplifications: neglect of gravity, replacing the crust with an hydraulic resistance, and use of the Green‐Ampt model. It is shown that these approximations are unnecessary and obscure or distort the dynamics of infiltration into crusted soils. The role of the crust may be summarized as a throttle on infiltration. It reduces all four of infiltration rate, cumulative infiltration, degree of wetting, and depth of penetration. The hydrologic effects are to increase runoff and potential for erosion. Significant for irrigated and dry land agriculture is the harmful reduction of the water in the root zone available to plants.
Partitioning of hydrophobic contaminants in the vadose zone in the presence of a nonaqueous phase
Authors: Schaefer C. E. , Unger D. R. , Kosson D. S.
Published: February 2004

Partitioning behavior of organic contaminants in the vadose zone may be influenced by the presence of a nonaqueous phase liquid (NAPL). The bulk NAPL phase not only serves as a sink for hydrophobic contaminants but may also cover a significant fraction of the soil surface, reducing the surface area available for vapor‐solid adsorption. Experiments were carried out to examine the applicability of binary partitioning parameters when applied to a multiphase system. Dodecane was used as the model NAPL phase, while toluene and benzene were used as the model hydrophobic contaminants. Several soil types and water contents were examined. Results indicated that two‐phase equilibrium parameters were sufficient to predict partitioning among the various phases if fractional soil surface coverage by each phase was considered. A previously developed model was extended to account for the presence of NAPL and was used to describe the multiphase contaminant partitioning presented in this work.
Importance of biogeochemical processes in modeling stream chemistry in two watersheds in the Sierra Nevada, California
Authors: Meixner Thomas , Brown Aaron , Bales Roger C.
Published: February 2004

Two small (0.22 and 0.48 ha) alpine watersheds in the Sierra Nevada of California were studied during the 1992 and 1993 snowmelt seasons to evaluate the importance of soil properties and processes on chemical concentrations in the discharges from each watershed. Watershed 1 was surveyed as having 26% soil cover, whereas watershed 2 was 10% soil covered. Watershed 2 had greater H+and nitrogen consumption than watershed 1 but similar cation and sulfate concentrations despite having one fourth the surveyed soil volume per unit area as watershed 1. Daily stream concentrations simulated with the Alpine Hydrochemical Model (AHM) matched the data well, after a systematic model calibration with a subset of the data. We found that the structure of the AHM and the hydrologic parameters developed for the nearby 1.2 km2Emerald Lake watershed could be applied to these watersheds with only small adjustments; chemical parameters required considerably more adjustment, reflecting a greater degree of chemical versus physical heterogeneity at this scale. Calibration for watershed 2 gave a higher percent base saturation (19 versus 4%) and lower streamurn:x-wiley:01480227:media:wrcr7928:wrcr7928-math-0001versus 10−2.6atm) than for watershed 1 and three times the soil reactivity (expected) of a field survey. Areas mapped as exposed bedrock in the catchments apparently contributed cations and alkalinity to stream water to a greater extent than did neighboring areas of soil. Areas of exposed bedrock were a larger nitrogen sink than the adjoining areas of soil. ThepH and acid‐neutralizing capacity of surface runoff in both catchments were less sensitive to changes in atmospheric deposition than at the nearby Emerald Lake watershed. This decreased sensitivity was due to (1) a less pronounced ionic pulse, (2) less retention of sulfate in the soil, and (3) greater nitrate retention.
A modified invasion percolation model for low‐capillary number immiscible displacements in horizontal rough‐walled fractures: Influence of local in‐plane curvature
Authors: Glass Robert J. , Nicholl Michael J. , Yarrington Lane
Published: February 2004

We develop and evaluate a modified invasion percolation (MIP) model for quasi‐static immiscible displacement in horizontal fractures. The effects of contact angle, local aperture field geometry, and local in‐plane interfacial curvature between phases are included in the calculation of invasion pressure for individual sites in a discretized aperture field. This pressure controls the choice of which site is invaded during the displacement process and hence the growth of phase saturation structure within the fracture. To focus on the influence of local in‐plane curvature on phase invasion structure, we formulate a simplified nondimensional pressure equation containing a dimensionless curvature number (C) that weighs the relative importance of in‐plane curvature and aperture‐induced curvature. Through systematic variation of C, we find in‐plane interfacial curvature to greatly affect the phase invasion structure. As C is increased from zero, phase invasion fronts transition from highly complicated (IP results) to macroscopically smooth. In addition, measurements of fracture phase saturations and entrapped cluster statistics (number, maximum size, structural complication) show differential response between wetting and nonwetting invasion with respect to C that is independent of contact angle hysteresis. Comparison to experimental data available at this time substantiates predicted behavior.
Irregular bed forms in steep, rough channels: 1. Stability analysis
Authors: Furbish David Jon
Published: February 2004

A scaling analysis of the depth‐integrated momentum equations tailored to the rough bed conditions of mountain streams suggests that certain velocity correlation terms that arise from depth integration, and which normally can be neglected in the case of smoother alluvial channels, can be a significant part of the momentum balance in these steep channels. By introducing the kinetic energy equation of the time‐averaged motion to treat these correlation terms, which involve products of local deviations in velocity components about depth‐averaged values, a flow model that suitably characterizes streamwise accelerations is obtained. A linear stability analysis using a flow model that retains the streamwise correlation terms suggests that their effect is to strengthen the initial selection of bed form wavelengths, as reflected by sharpened peaks in curves of growth rate versus bed form wavelength. Wavelengths with zero migration rate are close to wavelengths having the largest growth rate; thus selection of fixed bars is strong. Critical width‐depth ratios necessary for bed form growth are significantly less than the critical ratios that are predicted when correlation terms are neglected. Moreover, a broader band of wavenumbers can be activated at a given width‐depth ratio, and bed form modes representing midchannel bars can be activated in a narrower channel than would otherwise be predicted. Thus alternate bars can initially “compete” with midchannel bars, particularly at low sediment transport rates. This competition probably contributes to the complexity of bed topography that is typical of rough, mountain channels.
Hydrological components of a young loblolly pine plantation on a sandy soil with estimates of water use and loss
Authors: Abrahamson Deborah A. , Dougherty P. M. , Zarnoch S. J.
Published: February 2004

Fertilizer and irrigation treatments were applied in a 7‐ to 10‐year‐old loblolly pine (Pinus taeda L.) plantation on a sandy soil near Laurinburg, North Carolina. Rainfall, throughfall, stemflow, and soil water content were measured throughout the study period. Monthly interception losses ranged from 4 to 15% of rainfall. Stemflow ranged from 0.2 to 6.5% of rainfall. Rainfall, leaf area index (LAI), basal area (BA), and the interactions of rainfall with LAI or BA influenced prediction models of throughfall, but not stemflow, on a stand level. We found significant differences due to the effects of treatments in the soil water of the top 0.5‐ and 1‐m soil layers by the beginning of the second growing season and throughout the remainder of the study period. Average daily water use and loss from a 1‐m soil layer reflected the low water‐holding capacity of the sand. Soil water in a 1‐m layer was rapidly depleted to within 10% of available water during periods of little or no rainfall. Irrigation did not significantly affect productivity and created a greater potential for loss of water to drainage below 1 m. On the basis of Zahner's [1966] method of soil water depletion in a sandy soil under forest cover, total drainage to below l m was 55% of evapotranspiration in unirrigated plots and 150% of evapotranspiration in irrigated plots.
Approximate Goodness‐of‐Fit Tests of fitted generalized extreme value distributions using LH moments
Authors: Wang Q. J.
Published: February 2004

Approximate goodness‐of‐fit tests of fitted generalized extreme value (GEV) distributions using LH moments are formulated on the basis of comparison of sample LH kurtosis estimates and theoretical LH kurtosis values of the fitted distributions. These tests are different from those that have been derived for testing the GEV distributions of which parameter values are known a priori. The tests are intended to answer the following questions: Does a fitted GEV distribution describe adequately a given data series? If not, can the GEV distribution function describe adequately the larger events in that data series for use for high quantile estimation? If so, what degree of emphasis on the larger events is needed in order that the GEV distribution becomes acceptable? The use of the GEV distribution in conjunction with the LH moment estimation method and the formulated tests should alleviate the need for finding the “correct” distribution. The tests are evaluated by Monte Carlo simulations using generated samples of both GEV and Wakeby distributions. Applications of the tests to observed annual maximum streamflow data are presented.
Seasonal streamflow forecasting in eastern Australia and the El Niño–Southern Oscillation
Authors: Piechota Thomas C. , Chiew Francis H. S. , Dracup John A. , McMahon Thomas A.
Published: February 2004

Previous studies have identified a strong link between climate variability in Australia and the El Niño–Southern Oscillation (ENSO). This paper describes the development and use of a seasonal streamflow forecast model based on an optimal linear combination of forecasts derived from climatology, persistence, the Southern Oscillation index (SOI), and equatorial Pacific sea surface temperatures (SST). The model builds on the work of the Australian Bureau of Meteorology and that of other researchers who have investigated southeast Australian rivers. The model is tested using 66 years of unimpaired streamflow data from 10 eastern Australian catchments. Results from testing the model further support the ENSO‐hydroclimate link, showing that eastern Australia generally receives below normal streamflow during El Niño conditions and above normal streamflow during La Niña conditions. In southeast Australia the SOI is a better predictor for July–September and October–December streamflow and the SST a better predictor of January–March and April–June streamflow. For many of the seasons and stations, the skill associated with the cross‐validation forecast is better than that drawn from the baseline condition of climatology.
An aggregation‐disaggregation approach to long‐term reservoir management
Authors: Turgeon André , Charbonneau Raymond
Published: February 2004

The problem is to find the monthly operating policy of Hydro‐Québec's 26 large reservoirs that maximizes the utility's expected profits over a period of several years. The problem is solved in a hierarchical way. First, the optimal operating policy of the whole system, represented by an aggregate model, is found by stochastic dynamic programming (SDP). This gives not only the hydroelectric energy to produce in a month but also, as is very important in a deregulated market, the expected marginal value of the hydroelectric energy produced. At the second level the expected marginal value of the potential energy stored in each river is determined by solving a SDP problem with two state variables: one for the energy content of the river and the other for the energy content of all the other rivers combined. These marginal values are used afterward to divide the hydroelectric production among the rivers. At the third level the production assigned to each river is distributed between the reservoirs so as to minimize the spillages first, and then the square of the deviations of the reservoir levels from the target level. The targets are adjusted to maximize the expected long‐term production of the river. The monthly inflows to the reservoirs are the only random variables in this problem.
Transport and biodegradation of solutes in stratified aquifers under enhanced in situ bioremediation conditions
Authors: Oya Shunji , Valocchi Albert J.
Published: February 2004

Understanding the effect of the heterogeneous subsurface environment upon fate and transport of biologically reactive solutes is necessary for effective field application of in situ bioremediation. We consider a scenario in which an electron acceptor is continuously input into an aquifer having initial uniform concentrations of an adsorbed pollutant and immobile microorganisms. Biodegradation is governed by dual Monod kinetics, and the aquifer is assumed to have vertical stratification of pore water velocity and retardation factor. We characterize solute transport behavior with a theoretical approach and derive a simple expression for the long‐term pollutant biodegradation rate. Our theoretical approach is based upon the observation that the balanced interactions between the biodegradation and mixing processes cause the solute and biomass concentration profiles to form traveling waves after a long elapsed time. The theoretical results indicate that the effective macrodispersion coefficients for the depth‐averaged solute fronts decrease to zero at large times and that the long‐term biodegradation rate is independent of longitudinal and transverse dispersion, the vertical variations of flow velocity and retardation factor, microbial growth kinetics, and initial biomass concentration. Numerical simulations verify the appearance of such asymptotic transport and biodegradation properties at large times but show that there is an early transient period which depends upon all these parameters and conditions. Our results demonstrate that transverse dispersion is the important process controlling the establishment of the asymptotic transport and biodegradation properties.
Effects of topical antiglaucoma drugs on apoptosis rates of conjunctival epithelial cells in glaucoma patients
Authors: Dog˘an Aysun Lanal , Orhan Mehmet , Söylemezog˘lu Figen , İrkeç Murat , Bozkurt Banu
Published: February 2004

Background: To investigate the effects of topical antiglaucoma drugs on apoptosis rates of conjunctival epithelial cells in vivo.

Methods: Specimens were obtained from the bulbar conjunctiva of 30 patients who underwent either cataract or glaucoma surgery. Of these 30 patients, 14 had glaucoma and received topical antiglaucoma drugs. The 16 patients in the control group had neither systemic nor ocular disease except cataract and they did not receive any medications. TUNEL (terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labelling) method was used to show the apoptosis of the conjunctival epithelial cells.

Results: Increased apoptosis rates were detected in specimens of patients who were on topical antiglaucoma therapy (mean ± SD 0.208 ± 0.154) when compared with the healthy subjects (mean ± SD 0.083 ± 0.102; P = 0.013). The apoptosis rates did not differ according to type, number or duration of drugs.

Conclusions: The apoptosis observed in the conjunctival epithelial cells might be due to the preservative benzalkonium chloride in the antiglaucoma medications because the apoptosis rates did not differ in patients using different types of medications.
Black eye drop bottle tips improve compliance
Authors: Stack Rebecca R , McKellar Malcolm J
Published: February 2004

Aim: To determine if dark coloured tips on eye drop bottles facilitate ocular therapy.

Methods: Eye drop bottles were modified by placing sterile black tape around the bottle tip. Patients on regular timolol therapy were asked to use bottles with the modified tip for one month. They then completed a questionnaire comparing the black tips with the standard tips on the bottle they normally use.

Results: Eighty‐eight per cent of patients found the black tipped bottles easier to use than bottles with the standard tip. Sixty‐eight per cent of patients had fewer occasions on which they needed to instil a second drop and 30% of patients touched their eyelid less when using the modified bottle tips.

Conclusion: Black coloured bottle tips aid ocular therapy. They are easier to use, result in less contact with the eye on instillation and patients note a reduction in need for a second or additional drop. This is likely to improve compliance and reduce contamination. A change in manufacturing practise should be encouraged.
Controlled trial of hyperbaric oxygen treatment for alkali corneal burn in the rabbit
Authors: Hirst Lawrence W , Summers Phillip M , Griffiths David , Bancroft Josephine , Lillicrap Gary R
Published: February 2004

Purpose: To evaluate the efficacy of hyperbaric oxygen therapy in the treatment of alkali‐induced corneal burns in an animal model.

Methods: Twenty‐four rabbits were randomized into a control group (n = 12) and hyperbaric oxygen treatment group (n = 12). After induction of anaesthesia, the alkali burn model was established by application of 1 N sodium hydroxide to one eye of each rabbit. The hyperbaric oxygen treatment group was treated each day for 21 days with hyperbaric oxygen at 2.4 Atmospheres Absolute (ATA) for 1 h. The eyes of the animals were examined daily for 2 weeks and then weekly until the end of the trial. The principal endpoint was that of perforation of the cornea at which time the animals were killed with a lethal dose of either intravenous or intraperitoneal barbiturate and the eyes immediately enucleated and fixed in 10% neutral buffered formalin. All animals in which complete healing took placed were also killed, the eyes removed, fixed and examined histologically. Photographs were taken of the rabbit's eyes at weekly intervals and the area of vascularization and epithelial defects in the hyperbaric and control groups were compared.

Results: Equal numbers (seven) of the control and hyperbaric oxygen treated groups had perforated corneas and there was no statistical difference in the mean time to perforation (control 30.1 days; treated 30 days). There was also no statistical difference between the two groups with respect to epithelial defect size.

Conclusion: Treatment with hyperbaric oxygen for 1 h daily for 21 days had no beneficial effect on alkali‐induced corneal burns.
Activation of ERK1/2 after neonatal rat cerebral hypoxia–ischaemia
Authors: Wang Xiaoyang , Zhu Changlian , Qiu Lin , Hagberg Henrik , Sandberg Mats , Blomgren Klas
Published: February 2004

Activation of extracellular signal‐related kinases (ERK1/2), also known as p42/44 mitogen‐activated protein kinase (MAPK), is considered important for neuronal survival, cell proliferation and apoptosis. In the present study, activation (phosphorylation) of ERK1/2 (P‐ERK) was investigated in brains of 7‐day‐oldrats after hypoxia‐ischaemia (HI). In damaged areas, P‐ERK‐positive neurons appeared immediately after HI and the staining remained for at least 8 h. At later time points, 24 and 72 h post‐HI, P‐ERK‐positive neurons were found in the core of the infarct and in the border zone to undamaged tissue. These cells also showed signs of DNA damage and calpain‐induced fodrin breakdown, indicative of injury. At 72 h post‐HI, P‐ERK was also observed in microglia in the border zone to the damaged area and in astrocytes and oligodendrocytes in white matter of both hemispheres. P‐ERK was strongly expressed in the subventricular zone in both hemispheres after HI at most time points, although the staining in the ipsilateral (damaged hemisphere) was stronger than in the contralateral (non‐damaged hemisphere). In summary, ERK1/2 activation occurred early in neurons after HI in the neonatal brain, and mainly in cells displaying signs of damage.
Striatal neurones show sustained recovery from severe hypoglycaemic insult
Authors: McDermott C. J. , Bradley K. N. , McCarron J. G. , Palmer A. M. , Morris B. J.
Published: February 2004

Glucose deprivation provides a reliable model to investigate cellular responses to metabolic dysfunction, and is reportedly associated with permanent cell death in many paradigms. Consistent with previous studies, primary cultures of rat striatal neurones exposed to 24‐h hypoglycaemia showed dramatically decreased sodium 2,3‐bis(2‐methoxy‐4‐nitro‐5‐sulfophenyl)‐2H‐tetrazolium‐5‐carboxanilide (XTT) metabolism (used as a marker of cell viability) and increased TUNEL staining, suggesting widespread DNA damage typical of apoptotic cell death. Remarkably, restoration of normal glucose levels initiated a sustained recovery in XTT staining, along with a concomitant decrease in TUNEL staining, even after 24 h of hypoglycaemia, suggesting recovery of damaged neurones and repair of nicked DNA. No alterations in the levels of four DNA repair proteins could be detected during hypoglycaemia or recovery. A reduction in intracellular calcium concentration was seen in recovered cells. These data suggest that striatal cells do not die after extended periods of glucose deprivation, but survive in a form of suspended animation, with sufficient energy to maintain membrane potential.
Amyloid‐beta increases acetylcholinesterase expression in neuroblastoma cells by reducing enzyme degradation
Authors: Hu William , Gray Noah W. , Brimijoin Stephen
Published: February 2004

Amyloid‐beta (Aβ) is the principal protein constituent of ‘senile plaques’ and is a suspected mediator in Alzheimer's disease (AD). Senile plaques also contain acetylcholinesterase (AChE; EC 3.1.1.7), which may have a role in promoting Αβ‐toxicity. We have found that Αβ can affect AChE expression in a neuron‐like line, the N1E.115 neuroblastoma cell. When 1 µmΑβ 1–42 or 25–35 was added for 24 h to differentiating N1E.115 in culture, AChE activity increased 30–40% in adherent cells, and 100% or more in nonadherent cells. The changes in both tetrameric (G4) and monomeric (G1) AChE forms were comparable. Turnover studies indicated that the elevation of AChE activity reflected slowed AChE degradation rather than accelerated synthesis. With a similar time course, Αβ also increased the quantity of muscarinic receptors on the plasma membrane. Immunocytochemistry for a lysosomal membrane protein (LAMP‐1) indicated no change in abundance or localization of lysosomes in treated cells. But decreased labeling by pH‐sensitive fluorescent dye pointed to an impairment of lysosomal acidification. We consider that the alteration of AChE expression after Αβ‐exposure could reflect lysosomal dysfunction, and might itself enhance Αβ‐toxicity.
Interaction of 14‐3‐3 with Bid during seizure‐induced neuronal death
Authors: Shinoda Sachiko , Schindler Clara K. , Quan‐Lan Jing , Saugstad Julie A. , Taki Waro , Simon Roger P. , Henshall David C.
Published: February 2004

Seizure‐induced neuronal death may involve coordinated intracellular trafficking and protein–protein interactions of members of the Bcl‐2 family. The 14‐3‐3 proteins are known to sequester certain pro‐apoptotic members of this family. BH3‐interacting domain death agonist (Bid) may contribute to seizure‐induced neuronal death, although regulation by 14‐3‐3 has not been reported. In this study we examined whether 14‐3‐3 proteins interact with Bid during seizure‐induced neuronal death. Brief seizures were evoked in rats by intraamygdala microinjection of kainic acid to elicit unilateral hippocampal CA3 neuronal death. Coimmunoprecipitation analysis demonstrated that although Bcl‐2‐associated death promoter (Bad) constitutively bound 14‐3‐3, there was no interaction between Bid and 14‐3‐3 in control brain. Seizures triggered Bid cleavage and a commensurate increase in binding of Bid to 14‐3‐3 within injured hippocampus. Casein kinases I and II, which can inactivate Bid by phosphoserine/threonine modification, did not coimmunoprecipitate with Bid. The largely uninjured contralateral hippocampus did not exhibit Bid cleavage or binding of 14‐3‐3 to Bid. In vitro experiments confirmed that 14‐3‐3β is capable of binding truncated Bid, likely in the absence of phosphoserine/threonine modification. These data suggest 14‐3‐3 proteins may target active as well as inactive conformations of pro‐apoptotic Bcl‐2 death agonists, highlighting novel targets for intervention in seizure‐induced neuronal death.
On the peculiarities of the diabatic framework: New insight
Authors: Ve’rtesi T. , Vibók Á. , Halász G. J. , Baer M.
Published: February 2004

In this article we consider the electronic diabatic presentation of a two-state system with the aim of earning insight regarding the distribution of conical intersections in a given region. In this process we revealed explicit relationship between the diabatic potentials and the locations of conical intersections. The study is accompanied with numerical examples as worked out for a model and ab initio potential energy surfaces of the Na+H2 system.
Thermodynamic manifestations of structure fluctuations in liquids
Authors: Patashinski Alexander Z. , Ratner Mark A.
Published: February 2004

Fluctuations of pressure and internal energy in a low-temperature liquid, generated by structure fluctuations, are related in a general and straightforward way to the differences between the long- and short-time thermodynamic susceptibilities. The relations are similar to, but not identical with, those between thermodynamic fluctuations and susceptibilities in classical statistical mechanics. The derivation is general and straightforward, and based on the assumption that the local structure is a slow-relaxing mode in low-temperature liquids and may be characterized by an order parameter.
Quantum-mechanical calculations on pressure and temperature dependence of three-body recombination reactions: Application to ozone formation rates
Authors: Charlo David , Clary David C.
Published: February 2004

A quantum-mechanical model is designed for the calculation of termolecular association reaction rate coefficients in the low-pressure fall-off regime. The dynamics is set up within the energy transfer mechanism and the kinetic scheme is the steady-state approximation. We applied this model to the formation of ozone O+O2+M→O3+M for M=Ar, making use of semiquantitative potential energy surfaces. The stabilization process is treated by means of the vibrational close-coupling infinite order sudden scattering theory. Major approximations include the neglect of the O3 vibrational bending mode and rovibrational couplings. We calculated individual isotope-specific rate constants and rate constant ratios over the temperature range 10–1000 K and the pressure fall-off region 10−7–102 bar. The present results show a qualitative and semiquantitative agreement with available experiments, particularly in the temperature region of atmospheric interest.
Absolute surface coverage measurement using a vibrational overtone
Authors: Pipino Andrew C. R. , Hoefnagels Johan P. M. , Watanabe Noboru
Published: February 2004

Determination of absolute surface coverage with sub-monolayer sensitivity is demonstrated using evanescent-wave cavity ring-down spectroscopy (EW-CRDS) and conventional CRDS by employing conservation of the absolute integrated absorption intensity between gas and adsorbed phases. The first C–H stretching overtones of trichloroethylene (TCE), cis-dichloroethylene, and trans-dichloroethylene are probed using the idler of a seeded optical parametric amplifier having a 0.075 cm−1 line width. Polarized absolute adsorbate spectra are obtained by EW-CRDS using a fused-silica monolithic folded resonator having a finesse of 28 500 at 6050 cm−1, while absolute absorption cross sections for the gas-phase species are determined by conventional CRDS. A measure of the average transition moment orientation on the surface, which is utilized for the coverage determination, is derived from the polarization anisotropy of the surface spectra. Coverage measurement by EW-CRDS is compared to a mass-spectrometer-based surface-uptake technique, which we also employ for coverage measurements of TCE on thermally grown SiO2 surfaces. To assess the potential for environmental sensing, we also compare EW-CRDS to optical waveguide techniques developed previously for TCE detection.
Semiclassical initial value treatment of correlation functions
Authors: Sklarz Temira , Kay K. G.
Published: February 2004

Two semiclassical, initial value representation (IVR) treatments are presented for the correlation function 〈ψ(f )|e−iĤt/ℏ|ψ(i)〉, where ψ(i) and ψ(f ), are energy eigenfunctions of a “zero-order” Hamiltonian describing an arbitrary, integrable, vibrational system. These wave functions are treated semiclassically so that quantum calculations and numerical integrations over these states are unnecessary. While one of the new approximations describes the correlation function as an integral over all phase space variables of the system, in a manner similar to most existing IVR treatments, the second approximation describes the correlation function as an integral over only half of the phase space variables (i.e., the angle variables for the initial system). The relationship of these treatments to the conventional Herman-Kluk approximation for correlation functions is discussed. The accuracy and convergence of these treatments are tested by calculations of absorption spectra for model systems having up to 18 degrees of freedom, using Monte Carlo techniques to perform the multidimensional phase space integrations. Both treatments are found to be capable of producing spectra of excited, anharmonic states that agree well with quantum results. Although generally less accurate than full phase space or Herman-Kluk treatments, the half phase space method is found to require far fewer trajectories to achieve convergence. In addition, this number is observed to increase much more slowly with the system size than it does for the former methods, making the half-phase space technique a very promising method for the treatment of large systems.
A theoretical study of small copper oxide clusters: Cu2Ox (x=1–4)
Authors: Dai Bing , Tian Li , Yang Jinlong
Published: February 2004

Density functional theory (DFT) calculations are performed to study Cu2Ox (x=1–4) clusters in their neutral, anionic and cationic states. The ground state structures are obtained and found to exhibit linear or near linear structures, which are different from the two- or three-dimensional ones suggested by the previous theoretical calculations. The calculated electron affinities of the clusters are in good agreement with the experimental ones. The low-lying excited states for the clusters are calculated using time-dependent DFT and used to assign the features in the photoelectron spectra. Our results compare well with the available experimental data.