bluuebunny/crossref_metadata_2025 huggingface dataset:
Standard Albanian — linguistic controversy in post-Communist Albania
Authors: Lloshi Xhevat
Published: May 2006

The status of Albanian as a national standard has become a matter of serious debate. In 1972 Standard Albanian (SA) was adopted in public communications and in schools. But after the political changes in Albania in 1991–1992 the language question was reopened, calling into question the SA. The roots of the present-day debate are to be found in the dialectal division of Albanian, the historical establishment of a number of written varieties, and the standardization achieved during the years of the Communist regime. This article describes how Standard Albanian was established and the recent developments. For the future it poses the question: Will there be one Albanian national identity, or two Albanian national identities? The answer is that Albanians already have a good standard language, though with many problems, of course, and much work needs to be done for its enrichment and improvement, but Albanians have no need to create a new standard, or to undergo a glosso-ectomy.
The Albanian language: developments in the lexicon under the new social and political order
Authors: Thomaj Jani
Published: May 2006

In the past decade the Albanian language has undergone a period of significant change in terms of lexical development. These developments are almost entirely attributable to extralinguistic factors. The turbulent transition from a centralized socialist system to a market economy in the 1990s was accompanied by an immediate opening of Albania to the outside world. This upheaval also brought about a social and intellectual liberation, a change in mental outlook, and freedom from the weight of dictatorship and the totalitarian mindset. The transformation from collectivized property to private property and the birth of political and cultural pluralism constituted a novel variable within Albanian society.

The pluralism of press and broadcast media and the phenomenal growth in the number of political parties are two important constituents for change in the lexical norm of the Albanian language, both in a positive and negative sense. A predisposition towards direct contact with Western languages and cultures, interpreted as a sign of the “Europeanization” of Albania, led to the proliferation of many foreign words, primarily English, into the lexicon of Albanian, especially in the domains of economics, trade, jurisprudence, information technology, politics, and administration. This study concerns itself with interpretation, classification, and examples of these changes.
The First Congress phenomenon: the case of Albanian
Authors: Memushaj Rami
Published: May 2006

In one of his papers devoted to the study of the “First Congress” phenomenon, J. Fishman points out that, in order to define a sound typology, many more such congresses need to be studied. Albanian researchers have had many discussions on the topic of congresses for the standardization of the Albanian language, but the Fishman project has not concluded any study to date of the “First Congress” phenomenon as pertains specifically to the Albanian language. This article studies this phenomenon according to criteria he set out. We use as our basis for analysis, linguistic meetings, conferences, and material extrapolated from Albanian associations over the last two centuries in order to identify which of them fulfill the criteria and thus enable a robust designation as the first congress of the Albanian language.
Computational Wear Prediction of UHMWPE in Knee Replacements
Authors: Zhao D , Gregory Sawyer W , Fregly BJ
Published: May 2006

A multibody dynamic contact model predicted the damage sustained by two tibial inserts tested under different conditions on an AMTI knee simulator machine. The model required a wear factor of 7.7 × 10−7 mm3/Nm to match the wear volume measured from the first insert after 0.86 million cycles of simulated gait. The model matched the medial and lateral damage depths measured from the second insert to within 0.3 mm after 5 million cycles of simulated gait and stair (10:1 ratio). Computational models may be valuable for screening new knee implant designs rapidly and performing sensitivity studies of component positioning issues.
Assessing Human Exposure to Perchlorate Using Biomonitoring
Authors: Blount BC , Valentín-Blasini L , Ashley DL
Published: May 2006

Because of health concerns surrounding widespread exposure to perchlorate, we developed a sensitive and selective method for measuring perchlorate in human urine using ion chromatography coupled with electrospray ionization tandem mass spectrometry. This method was applied to assess perchlorate levels in urine collected from a convenience population (N=27) consuming foods reported to contain perchlorate: milk, dairy products, and green leafy vegetables. Consumption of three or more servings of these foods in the 16 hours before urine sample collection was associated with significantly higher levels of perchlorate in urine (6.13±3.59 μg/g creatinine) compared with study participants consuming one or fewer servings of these foods (3.14±0.85 μg/g creatinine). These data suggest that diet can be an important source of perchlorate exposure and underscore the important role of selective and sensitive biomonitoring methods to assess human exposure to perchlorate from multiple sources in the environment.
Effect of Microstructure on Pit-to-Crack Transition of 7075-T6 Aluminum Alloy
Authors: Jones K , Hoeppner DW
Published: May 2006

The focus of this research was to gain an increased understanding of how microstructure influences pit growth, pit-to-crack transition, and critical crack propagation to fracture. Two thicknesses of 7075-T6 aluminum alloy were etched and subjected to corrosion fatigue in a 3.5% sodium chloride environment. 7075-T6 aluminum alloy is of particular interest to the aging aircraft community, as this alloy has been used extensively on wing and fuselage structures for both military and commercial aircraft in the past. Testing was interrupted at various intervals to obtain information on pit generation, growth, and potential cracking. Results indicated that microstructure has a significant influence on pit-to-crack transition and fatigue crack propagation. Short cracks (<100 μm) in a corrosion fatigue environment were strongly influenced by grain boundaries and crystallographic grain orientation. Constituent particles competed with corrosion pits as critical crack nucleation sites. Post-fracture analysis confirmed the presence of noncritical cracks within the corroded region, related to pitting and constituent particles.
Asymptotic Stress Fields for Thermomechanically Loaded Cracks in FGMs
Authors: Jain N , Chona R , Shukla A
Published: May 2006

The problem of a stationary crack in functionally graded materials (FGM), subjected to a combination of thermal and mechanical loading is considered. An asymptotic analysis coupled with Westergaard's stress function approach is used to characterize the stress field around the crack tip. Thermal and mechanical properties (e.g., elastic modulus, coefficient of thermal expansion, and thermal conductivity) are assumed to vary exponentially. The crack is assumed to be inclined to the direction of the property gradation. The thermal loading is taken to be a uniform heat flow in a direction inclined to the crack. The principal of superposition from linear elasticity is used to solve the problem, whereby the problem is divided into a number of subproblems. The first four terms in the expansion of the stress field are derived to explicitly bring out the influence of nonhomogeneity on the structure of the stress field. It is observed that the presence of heat flow produced no additional singularity and hence the classical inverse square root singularity still prevails around the crack tip. Using these stress field contours of constant maximum shear stress are generated and the effect of thermal loading on the crack-tip stress field is discussed.
Sensitivity Evaluation in Double Wall Radiography of Pipes and Multilayer Plates by Assessment the Monte Carlo Simulation
Authors: Edalati K. , Rokrok B. , Kermani A. , Seiedi M. , Movafeghi A. , Rastkhah N.
Published: May 2006

Image quality indicator (IQI) is selected based on the single and/or double wall thickness of pipe with or without considering the radiographic techniques or applied radiation source (x ray or gamma ray), in accordance with the sensitivity requirements of reference codes. Discrepancies in the codes and standards for sensitivity evaluation and IQI selection have been investigated in the present work and some experiments have been performed to measure the gamma ray or x-ray radiographic sensitivity for pipes and plates to compare the results with sensitivity requirements of the standards. Due to the considerable effect of scattering on the sensitivity, Monte Carlo method has also been used to simulate the scattering for gamma ray radiography of pipes and plates. Experiments revealed that 2% sensitivity based on the single wall thickness was attainable for double wall exposure and single wall viewing (DWSI) technique, but it could not be easily obtained for double wall exposure and double wall viewing (DWDI) gamma ray technique. Higher sensitivity was obtained for x-ray radiography and a considerable sensitivity reduction was found for in-service radiography of pipes. Achieved sensitivities were in good agreement with measured effective attenuation coefficients and simulation results which confirmed that scattering was, respectively, higher for DWDI radiography of pipe, radiography of single layer plate, and DWSI radiography of two layer plate with identical penetrated thickness. Therefore, IQI selection was proposed to be based on the single wall thickness of component except for DWDI Gamma ray radiography, which was proposed to be based on the double wall thickness.
Structural Analysis or Cultural Analysis? Competing Perspectives on the “Standard Pattern” of West African Rhythm
Authors: AGAWU KOFI
Published: May 2006

Polyrhythmic dance compositions from West Africa typically feature an ostinato bell pattern known as a time line. Timbrally distinct, asymmetrical in structure, and aurally prominent, time lines have drawn comment from scholars as keys to understanding African rhythm. This article focuses on the best known and most widely distributed of these, the so-called standard pattern, a seven-stroke figure spanning twelve eighth notes and disposed durationally as <2212221>. Observations about structure (including its internal dynamic, metrical potential, and rotational properties) are juxtaposed with a putative African-cultural understanding (inferred from the firm place of dance in the culture, patterns of verbal discourse, and a broad set of social values) in order to further illuminate the nature of African rhythm, foster dialogue between structural and cultural perspectives, and thereby contribute implicitly to the methodology of cross-cultural analysis.
Normalizing the Abnormal: Disability in Music and Music Theory
Authors: STRAUS JOSEPH N.
Published: May 2006

The emerging interdisciplinary field of disability studies takes as its subject matter the historical, social, and cultural construction of disability. After a brief introduction to disability studies, this article explores the interconnected histories of disability and music as they are manifested in three theoretical approaches to late eighteenth- and early nineteenth-century Western art music (the musical Formenlehre and the tonal theories of Schoenberg and Schenker) and in three works by Beethoven and Schubert. Around the turn of the nineteenth century in Western Europe, disability began to be understood not as something natural and permanent but rather as a deviation from a normative standard, and thus subject to possible remediation. In the same time and place, art music also underwent a significant shift (reflected in the more recent theoretical traditions that have grown up around it), one that involved an increasing interest in rhetorically marked deviations from diatonic and formal normativity, and the possibility of their narrative recuperation. The article describes ways in which language about music and music itself may be understood both to represent and construct disability. More generally, it suggests that disability should take its place alongside nationality, ethnicity, class, gender, and sexual orientation as a significant category for cultural analysis, including the analysis of music.
Henry Cowell and John Cage: Intersections and Influences, 1933–1941
Authors: MILLER LETA E.
Published: May 2006

This article explores, through examination of correspondence and other primary sources, the close interaction between Henry Cowell and John Cage from 1933 to 1941 in the areas of percussion music, dance, world musics, the prepared piano, electronic sounds, micro-macrocosmic forms, sliding tones, and elastic composition. Several works are examined in detail, among them Cowell's Pulse (which anticipated Cage's micro-macrocosmic forms in the Constructions) and Cage's Imaginary Landscape No. 1 (whose electronic slides addressed Cowell's prediction that the “future of music” lay in the perfection of percussion and sliding tones). A previously unavailable recording of Imaginary Landscape No. 1 by Cage's ensemble reveals an unexpected interpretation of the score. Appendices present a chronology of events, a 1937 letter from Cowell to Cage, and a little-known set of Cage's program notes from 1940.
Visual Performance and Ocular System Structure of Kokanee and Sockeye Salmon following Strobe Light Exposure
Authors: Novales Flamarique Iñigo , Hiebert Steve , Sechrist Juddson
Published: May 2006

The use of flashing strobe lights to deter salmon from dam intakes and other hazardous underwater structures has become an appealing method for reducing salmon mortalities. However, no research has been carried out to determine how strobe light emission could affect the visual system of salmonid fishes. The present study investigated behavioral and ocular system changes after short-term (1- and 5-min) and long-term (3-h) exposure of kokanee and sockeye salmon (the lacustrine and anadromous forms of Oncorhynchus nerka). The onset of the escape response to an overhead shadow was different between treatments. Fish exposed for 1 or 5 min showed a response within 5 and 25 min of treatment, respectively, whereas the 3-h-exposed sockeye salmon responded a minimum of 64 h postexposure. All the retinas and lenses examined showed the same characteristics regardless of treatment. We conclude from these results that strobe exposure for 1 min or more induces a state of torpor in sockeye salmon, but exposure for no longer than 5 min does not induce permanent damage to the ocular system.
Repairs to River Trent navigation locks 1981–2002
Authors: Pickles J.
Published: May 2006

A series of repairs to three large concrete locks on the River Trent navigation was carried out between 1981 and 2002, involving works to counter the effects of degrading Mercia Mudstone foundation material and unsatisfactory stability of the structures. The current paper describes the history of the locks and the problems which developed, the assessments and investigation undertaken to determine the failure modes and the development of appropriate repair strategies. Significant factors included closure of the navigation, dewatering arrangements and temporary load cases, the preservation of existing stability and the effects of difficult site access. Construction activities are also briefly described. The projects originated from emergency works following a near failure at Stoke Lock (1981–1983), reactive works following monitoring at Newark Nether Lock (1993/1994) and preventative works identified through an asset inspection process at Cromwell Lock (2001/2002). The 1981–1983 works involved external sheet pile anchors and ties and a reinforced concrete trough section built in the lock chamber together with major temporary works. At Newark Nether, mini-piling was installed through the lock walls to improve stability prior to replacement of the lock floor, avoiding many of the temporary works needed at Stoke Lock. The Cromwell Lock works were similar to Nether Lock but utilised vertical mini-piling and an underfloor drainage system in a refinement of earlier designs. Use was made of British Waterways' own temporary works equipment where available.
An improvement on Magnel's diagram, and an application
Authors: Calladine C. R.
Published: May 2006

In designing the cross-section of a prestressed concrete beam that must withstand, over its history of loading, a known range of bending moments, the engineer must satisfy four inequalities which represent the allowable stress limits (+/–) at the upper and lower surfaces of the beam, respectively. Magnel described a graphical plot of these inequalities, which provided a two-dimensional ‘permissible region’ of prestressing force and thrust eccentricity in the form of a quadrilateral. Here a different way of plotting the same four inequalities is demonstrated, so that the ‘permissible region’ is always in the simpler form of a parallelogram. This ‘new’ plot is easier to deal with than Magnel's, and its advantages are listed. Also, an example is given of the use of the new plot in designing the thrust profile for a three-span bridge beam—an example originally given by Burgoyne to illustrate a point made first by Low.
Membrane action in ground-bearing concrete slabs
Authors: Eyre J. R.
Published: May 2006

Loading a ground-bearing slab at a location distant from the slab edge will inevitably incur membrane action. This membrane action can result in considerable enhancement of maximum load-carrying capacities. Although the enhancement may not be as great as for suspended slabs laterally restrained by their supports, it is nevertheless still substantial. Now that slabs are often continuously cast over large areas there may be considerable benefit from taking advantage of this load-carrying enhancement. The present paper presents a theoretical study of the effects of membrane action in these circumstances. It suggests that the inability of previous theoretical models to reproduce the failure loads from tests on slabs or to account for the considerable scatter in results may be the result of ignoring membrane action. An upper-bound plastic analysis is used to shed new light on the evolution of mechanisms and shows that, depending on stiffness, slabs on grade reach collapse loads with one of two modes. Either collapse takes place in flexure at a peak of the non-linear load–deflection behaviour or by punching through provoked by a through-depth crack at the perimeter of the loaded area. With pure flexure plastic methods, past analyses have failed to provide a non-trivial estimate of the size of the failing mechanism. Inclusion of membrane action is shown to predict the radius of the probable preferred collapse mechanism. A parametric study is provided, but further research work providing experimental scrutiny and convenient design routines is needed before this is of immediate benefit to the practitioner.
Simplified dynamic inelastic analysis of tall buildings
Authors: Ju Y. K.
Published: May 2006

Since the Kobe and Northridge earthquakes, static inelastic analysis has become an accepted and simple method for the seismic evaluation of high-rise buildings. In this method, the lateral load is monotonically increased with the same profile to find the ultimate capacity of the structure. Pushover analysis, however, has a limitation in the evaluation of a higher-mode dominant structure: for this reason, inelastic time history is used to compensate. In engineering practice, using inelastic time history analysis to evaluate the inelastic capacity of a building is impractical for tall buildings owing to the amount of computational time required and the difficulties in interpreting results. Therefore, a simplified inelastic analysis method is required for practical application. In the present paper, a simplified dynamic inelastic analysis (SDIA) method using elastic and inelastic response spectrums is introduced as a way to perform an inelastic analysis of a structure. The relative accuracy and efficiency of SDIA are explored by comparing the results with those of time history analysis software, DRAIN-2DX. The results of SDIA and DRAIN-2DX are almost identical, while with SDIA the computational time is dramatically reduced and time-consuming efforts interpreting results are saved.
On-site wastewater treatment and reuses in Japan
Authors: Gaulke L. S.
Published: May 2006

On-site wastewater treatment poses a challenging problem for engineers. It requires a balance of appropriate levels of technology and the operational complexity necessary to obtain high-quality effluent together with adequate reliability and simplicity to accommodate infrequent maintenance and monitoring. This review covers how these issues have been addressed in on-site wastewater treatment in Japan (termed johkasou). On-site systems in Japan range from outmoded designs that discharge grey water directly into the environment to advanced treatment units in high-density areas that produce reclaimed water on-site. Japan is a world leader in membrane technologies that have led to the development of on-site wastewater treatment units capable of water-reclamation quality effluent. Alternative ideas being pursued for on-site technologies also include separate waste stream collection, which would provide for more efficient treatment and reuse. Night soil treatment plants, where sludge from on-site systems is treated, are also distinctive to Japan, serving 37 million people. Japan has governmental regulations in place to ensure routine inspections of on-site units; furthermore, subsidies are available to reduce the cost of on-site systems for building owners. Lessons learned in on-site wastewater treatment in Japan have applications worldwide, from regions where water is scarce, to high-density areas in developing countries that currently lack sewer infrastructures.
Modelling sewer failure by evolutionary computing
Authors: Savic D. , Giustolisi O. , Berardi L. , Shepherd W. , Djordjevic S. , Saul A.
Published: May 2006

The sewer system is a service that is expected to function without interruptions. Continuous assessment, maintenance and rehabilitation are the key to maintaining a required level of service at an acceptable cost. An appropriate and cost effective prioritisation scheme for periodical surveys could be built based on failure data collected by sewerage companies over time. Such a scheme could be achieved using data-driven modelling techniques jointly with engineering knowledge of the failure mechanisms. This paper presents a descriptive analysis performed on a real database containing collapse and blockage incident records for a large sewer system in the UK. Starting from a statistical study of both failure types, the most important variables are identified and a classification scheme is suggested. Then, using a hybrid modelling technique, evolutionary polynomial regression, two different formulas for blockage events and collapse failures are obtained and their engineering interpretation is offered.
Analysing river bank seepage with a synthetic design hydrograph
Authors: Butera I. , Tanda M. G.
Published: May 2006

The design conditions of a river embankment are usually computed in a steady state, in a similar way to those due to the maximum river level of an assigned return period. The seepage analysis of the water pressure that stresses the embankment, with an increase in the risk of failure owing to both static instability and piping effects, results in an overly prudent evaluation that can be recognised as a non-economic design. The seepage steady state condition is, however, rarely verified in most river embankments, owing to the limited duration of floods and the poor conductivity of the soils that are usually adopted to construct river banks. Attempts to design in an unsteady regime have been made in recent years by means of mathematical models, but the selection of a design hydrograph in a river remains an ongoing problem. Over recent years, a new procedure for the identification of an efficient synthetic design hydrograph (SDH), with an assigned return period, has been developed by Maione and co-workers. This procedure has been successfully applied in the design of flood control reservoirs and in the evaluation of flood routing in rivers with large flood plain storage. In the current paper this SDH is applied in the analysis of seepage through a river embankment, as an attempt to design the river embankment in an unsteady regime; the SDHs of a given return period are applied to a levee with a simple geometry using a semi-analytical model and the main hydraulic quantities (maximum water level, time of maximum, etc.) of the seepage through the soil can be determined. All the real floods are then used as input for the model and the main hydraulic quantities of each flood are determined. The reliability of the design flood methodology has been tested by way of a comparison between the outcomes from the SDHs and the application of real floods.
Predicting runoff in ungauged UK catchments
Authors: Lee H. , McIntyre N. R. , Wheater H. S. , Young A. R.
Published: May 2006

An important challenge for hydrologists is to develop a capability for predicting flow time-series in ungauged catchments, where historic flow records are not available to support model calibration. Using a database of 131 well-gauged UK catchments, this paper develops regression relationships between known catchment characteristics and parameters of a conceptual rainfall–runoff model. These relationships allow predictive models to be specified without calibration. In an attempt to improve the relevance of the relationships, the catchments are grouped into more and less permeable catchment types and regression equations are identified for each group separately. Also, equations more applicable to predicting high flows are identified separately to those more applicable to predicting low flows. Physically meaningful relationships between model parameters and catchment characteristics are generally absent. Despite this, results indicate that the best regression model improves the capability of predicting the higher range of flows in the less permeable catchments; however predicting low flows in these catchments and the full range of flows in more permeable catchments remains a challenge.
Air entrainment and oxygen transfer in high-head gated conduits
Authors: Ozkan F. , Baylar A. , Ozturk M.
Published: May 2006

Air may be entrained into flowing water by design or inadvertently. Air entrained into flowing water at a hydraulic structure may be beneficial from the standpoint of oxygen recharge. When the gate of a high-head outlet conduit is partly opened, a negative pressure draws the air in through the air vent. Air that is entrained into the water is instantly forced downstream in the form of small air bubbles. The solution of oxygen into the water results from the air entrainment downstream of the high-head gated conduit. Moreover, high pressure in high-head gated conduit flow systems also facilitates the solution of oxygen into the water. Numerous model studies and a few field measurements have been conducted to determine the amount of air demand by closed conduits. The literature search did not identify any published analytical or physical studies of the dissolved oxygen levels produced in gated conduits. Therefore, experimental studies were conducted to investigate aeration efficiency of high-head gated conduit flow systems by using a simplified experimental configuration. It was observed from the results that almost full oxygen transfer, up to the saturation value, occurred at high-head gated conduits. Accordingly, it was concluded that high-head gated conduit flow systems have an extremely high efficiency for transferring oxygen from air bubbles to water.
Modelling sediment loads in the Lower Ganges, Bangladesh
Authors: Tarekul Islam G. M. , Jaman S. T.
Published: May 2006

The Ganges is one of the three major rivers in Bangladesh. It is a sediment laden, wide, meandering river. This paper deals with the stochastic modelling and prediction of sediment loads of the Lower Ganges river in Bangladesh. The annual variability of sediment loads has been examined. The annual sediment load series is trend free at 5% significance level. The means and standard deviations of monthly sediment load data show periodicity. Monthly sediment load data have been modelled and predicted using the Thomas–Fiering model for the dependent stochastic component and by taking variable month-to-month correlation structures into account. The statistical parameters of observed and predicted data fit very well and hence the predicted sediment load data may be used for future planning of water resource projects in Bangladesh. The limitations of the model have also been discussed.
Improving allocation of irrigation water in southwest India
Authors: Smout I. K. , Gorantiwar S. D.
Published: May 2006

Irrigation schemes in southwest India are heterogeneous in crops, area of irrigation units, soils and climate. The areas planned for irrigation each year under different crops and the scheduled duration of irrigation to each farmer are estimated, however, based on assumed uniform characteristics (planned schedule). In practice the schedules are not followed and users mostly over-irrigate their fields (the actual schedule). In this paper a simulation–optimisation model is used to develop two alternative (proposed) schedules based on full irrigation and on optimised deficit irrigation within the framework of area-proportionate water distribution, taking heterogeneity into account. As a case study, the allocation and water delivery plans were obtained for one irrigation scheme for the actual, planned and proposed schedules and compared using the simulation–optimisation technique. This showed that the proposed schedule for deficit irrigation had the maximum monetary productivity (total net benefits) and area productivity (irrigated area) and that the equity of both proposed schedules was much higher than those for either the planned or actual schedules. The proposed schedules can be adopted within the framework of the existing system of water distribution, which shows that there is considerable scope for improvement in the performance of existing irrigation schemes without major capital investment.
Peroxisome proliferation and antioxidant enzymes in transplanted mussels of four basque estuaries with different levels of polycyclic aromatic hydrocarbon and polychlorinated biphenyl pollution
Authors: Orbea Aamia , Cajaraville Miren P.
Published: May 2006

We aimed to determine the effects of changes in polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) bioavailability on peroxisome proliferation and antioxidant enzymes to assess their potential use as pollution biomarkers. For this, mussels (Mytilus galloprovincialis) were sampled in Txatxarramendi and transplanted to Arriluze, Muskiz, and Plentzia (northern Spain), and vice versa. Arriluze was the most heavily polluted site, followed by Plentzia, Txatxarramendi, and Muskiz. Animals transplanted from a polluted station to a cleaner station lost contaminant load in three to six weeks, and when transplanted to a more polluted station, they accumulated PAHs and PCBs accordingly. Peroxisomal acyl-A oxidase (AOX) activity was the highest in animals from Arriluze, and animals transplanted to Arriluze showed increased AOX activity, reaching the levels of native mussels. Mussels from Txatxarramendi showed the lowest peroxisomal volume density (Vvp). Among mussels from Txatxarramendi, only those transplanted to Plentzia showed increased Vvp, whereas animals from Arriluze and Muskiz transplanted to Txatxarramendi after 2 d and six weeks, respectively, had decreased Vvp. Two days after transplant, superoxide dismutase and glutathione peroxidase activities were significantly lower in mussels from Arriluze and Muskiz, respectively, than in those from Txatxarramendi and than in animals transplanted to Txatxarramendi from these stations. In conclusion, transplant experiments with mussels are useful to assess the effects of pollution. Peroxisome proliferation, measured as induction of AOX or increased Vvp, shows great potential as a biomarker of pollution to be included in pollution monitoring programs. In the present work, we have demonstrated that peroxisome proliferation is a reversible phenomenon in mussels.
Accumulation of polychlorinated biphenyls from floodplain soils by passerine birds
Authors: Neigh Arianne M. , Zwiernik Matthew J. , Bradley Patrick W. , Kay Denise P. , Jones Paul D. , Holem Ryan R. , Blankenship Alan L. , Strause Karl D. , Newsted John L. , Giesy John P.
Published: May 2006

Eggs, nestlings, and adults of the eastern bluebird (Sialia sialis) and house wren (Troglodytes aedon) were collected at a polychlorinated biphenyl (PCB)-contaminated site and a reference location on the Kalamazoo River (MI, USA). Eggs and nestlings of eastern bluebirds at the more contaminated location contained concentrations of 8.3 and 1.3 mg/kg, respectively, of total PCBs and 77 and 6.3 ng/kg, respectively, of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs). Eggs, nestlings, and adults of house wrens from the contaminated location contained 6.3, 0.77, and 3.2 mg/kg, respectively, of PCBs and 400, 63, and 110 ng/kg, respectively, of TEQs. Concentrations of total PCBs and TEQs in tissues at the more contaminated location were significantly greater than concentrations in tissues at the reference site for all tissue types of both species. Exposures of the two species studied were different, which suggests that terrestrial-based insectivorous passerine species, foraging in the same area, may have differential exposure to PCBs depending on specific foraging techniques and the insect orders that are targeted. Despite the greater accumulation of PCBs at the more contaminated location, the risk of exposure to PCBs did not exceed the threshold for adverse effects at either location.
Concentration of contaminants in breeding bird eggs from the Colorado River Delta, Mexico
Authors: García-Hernández Jaqueline , Sapozhnikova Yelena V. , Schlenk Daniel , Mason Andrew Z. , Hinojosa-Huerta Osvel , Rivera-Díaz Juan José , Ramos-Delgado Norma Alicia , Sánchez-Bon Gerardo
Published: May 2006

Organic contaminants (organochlorine [OC], organophosphorus [OP] pesticides and polychlorinated biphenyls [PCBs]), and metals (As, Cd, Hg, Pb, and Se) are a concern to avian health in the Colorado River delta, Mexico. We determined concentrations of contaminants in eggs of three breeding species of birds from the delta (mourning doves [Zenaida macroura], burrowing owls [Athene cunicularia], and marsh wrens [Cistothorus palustris]). We collected 27 eggs of mourning doves, eight eggs of burrowing owls, and 18 eggs of marsh wrens for analyses. Polychlorinated biphenyls, OC, and OP pesticides were analyzed by gas chromatography equipped with an electron capture detector, and metals were analyzed by inductively coupled plasma mass spectrometry. The non-ortho PCB congeners (PCB 77 and 126) were found in mourning dove and burrowing owl eggs at concentrations in which hatchability can be affected. Mean selenium concentration found in marsh wren eggs (5.6 μg/g dry wt) exceeded the level of concern. Arsenic and Cd were found at higher than normal concentrations, Hg concentrations did not exceed the level of concern in any of the species, and Pb concentrations were higher in eggs of species subject to hunting. With the exception of lead, marsh wren eggs contained the highest metal concentrations.
Dynamics of cadmium accumulation and effects in common carp (Cyprinus carpio) during simultaneous exposure to water and food (Tubifex tubifex)
Authors: Reynders Hans , Van Campenhout Karen , Bervoets Lieven , De Coen Wim M. , Blust Ronny
Published: May 2006

In this study, the influence of exposure time and concentration on the accumulation of cadmium and the occurrence of adverse effects was investigated when carp were simultaneously exposed through contaminated water and food. As exposure concentrations increased (9, 105, and 480 μg/L through water and 9.5, 122, and 141 μg/g dry weight through food) the accumulation pattern of cadmium changed, with progressively more cadmium being accumulated in the liver and especially the kidney and less in the gills and the intestine. A strong concentration- and time-dependent effect of cadmium exposure on plasma calcium concentrations was observed, leading to a decrease, with approximately 16% in the mid group and up to 50% in the group exposed to the highest cadmium concentration. Also at the highest exposure concentrations, sodium and chloride levels as well as plasma osmolality were significantly reduced, indicating a disturbed ion homeostasis. Furthermore, an increase in plasma alanine transaminase activity indicated liver damage caused by the cadmium accumulation in this organ. At the end of the experiment, general stress responses such as decreased hematocrit, growth, and mortality (17%) also were observed. All together, these results suggest that plasma hypocalcemia as an ion-disruptive phenomenon is the most sensitive effect during cadmium exposure, although the occurrence and magnitude both depend on exposure time and concentration.
Detoxifying toxicants: Interactions between sulfide and iron toxicity in freshwater wetlands
Authors: van der Welle Marlies Elizabeth Wilhelmina , Cuppens Mieke , Lamers Leon Peter Maria , Roelofs Jan Gisbert Maria
Published: May 2006

In many Dutch freshwater wetlands, concentrations of sulfate in the surface water and groundwater have increased. It is especially in peaty areas that this can lead to problems, including the reduction of sulfate to toxic sulfide. Our aquarium experiments showed that even low sulfide concentrations of 50 μmol/L are toxic to the freshwater macrophyte Nitella flexilis and the freshwater oligochaete Ophidonais serpentina. Sulfide toxicity can be modified by the availability of free iron in soil moisture or sediment from iron-rich groundwater discharge. The iron precipitates the sulfide, thereby immobilizing it and decreasing its toxicity. However, iron itself can be a toxicant as well. We found a detoxifying effect of moderate iron concentrations on sulfide toxicity, as well as a toxic effect of high iron concentrations on the growth of Potamogeton acutifolius. At the intermediate range, the formation of metal sulfides can simultaneously decrease metal and sulfide toxicity. Results of the experiments are discussed in relation to hydrological changes in freshwater wetlands.
Chronic toxicity of silver to the sea urchin (Arbacia punctulata)
Authors: Ward Timothy J. , Kramer James R. , Boeri Robert L. , Gorsuch Joseph W.
Published: May 2006

The chronic toxicity of silver to the seaurchin (Arbacia punctulata) was determined in 30%o salinity seawater during a three-part study: A fertilization test (1-h sperm exposure), a 48-h embryo test, and a 30-d adult test. Combined data from the three tests resulted in a lowest-observed-effect concentration of 19 μg/L, a no-observed-effect concentration of 8.6 μg/L, and a maximum acceptable toxicant concentration of 13 μg/L, based on measured concentrations of dissolved silver. The 96-h median effective concentration was 40 μg/L, and the acute to chronic toxicity ratio was 3.1. During the tests, measured concentrations of free ionic silver (Ag+) were only 0.0027 to 0.0046% of dissolved silver concentrations, as predicted by ion-speciation theory. Some measured Ag+ concentrations were lower than predicted, indicating the presence of other ligands in the seawater test media. These strong sulfide ligands were exuded by the exposed sea urchins into the seawater (where Ag-sulfide complexes formed) in amounts that increased in direct proportion to the silver concentration during the toxicity test. This suggests a toxicity-defense mechanism that functioned by modifying the chemistry of the surrounding external medium.
The fate of chiral organochlorine compounds and selected metabolites in intraperitoneally exposed arctic char (Salvelinus alpinus)
Authors: Wiberg Karin , Andersson Patrik L. , Berg Håkan , Olsson Per-Erik , Haglund Peter
Published: May 2006

The fate of chiral organochlorine compounds (OCs) and selected metabolites in exposed Arctic char (Salvelinus alpinus) was investigated. The contaminants α-hexachlorocyclohexane (α-HCH), cis-chlordane, 13C4-heptachlor, o,p′-DDT, and the atropisomeric chlorinated biphenyls (CBs) 95, 132, 136, 149, and 174 were solved in peanut oil and injected into the peritoneal cavity. The exposed fish were sampled three times during a five-week period, and the OC residues and detected metabolites (heptachlor-exo-epoxide) were quantified in muscle and liver tissues by chiral and achiral gas chromatography-mass spectrometry and gas chromatography-electron-capture detection. Peak concentrations were reached after one to two weeks, and thereafter, the levels declined. At the end of the experiment, liver concentrations had decreased 76 to 92% relative to peak concentrations, whereas muscle concentrations showed a moderate decline (5–38%), with the exception of α-HCH (91%). Hydrophobicity and steric hindrance were shown to influence the assimilation process, and a significant linear relationship between the product of the steric hindrance coefficients and the inverse of the octanol-water partition coefficients (Kow) versus peak concentration was found for the CBs (r2 = 0.86, p = 0.02). The assimilation of the contaminants into muscle and liver tissues generally resulted in racemic mixtures, whereas elimination was enantioselective for α-HCH, cis-chlordane, o,p′-DDT, CB-132, and CB-136. The chiral heptachlor metabolite 13C4-heptachlor-exo-epoxide was formed in the fish. The enantiomeric composition of the formed metabolite indicated racemic formation, whereas the elimination process appeared to be enantioselective.
Spatial trends and associated biological responses of organochlorines and brominated flame retardants in hatchlings of North Atlantic kittiwakes (Rissa tridactyla)
Authors: Murvoll Kari Mette , Skaare Janneche Utne , Moe Børge , Anderssen Endre , Jenssen Bjorn Munro
Published: May 2006

Persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), some organochlorinated pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCD), were analyzed in yolk sacs of kittiwake (Rissa tridactyla) hatchlings from Kongsfjorden at Svalbard (Norwegian Arctic; 79°N) and from Runde, an island on the coast of Norway (62°N). Retinol (vitamin A), retinyl palmitate, and α-tocopherol (vitamin E) were measured in plasma and liver of the hatchlings to examine whether these vitamins were associated with the POPs. Higher levels of PCBs and OCPs were found in hatchlings from Kongsfjorden than in hatchlings from Runde. However, HBCD levels were significantly lower in hatchlings from Kongsfjorden compared to those in hatchlings from Runde. No differences between the two populations of kittiwake hatchlings were found regarding levels of PBDEs. In comparison with seabirds from other European waters and the Canadian Arctic, the kittiwakes seemed to have relatively high levels of PBDEs and HBCD. No effects on morphological variables or vitamin levels by the POPs were revealed, but multivariate regression indicated that liver tocopherol levels may be influenced by POPs.
Uptake and elimination of ionizable organic chemicals at fish gills: I. Model formulation, parameterization, and behavior
Authors: Erickson Russell J. , McKim James M. , Lien Gregory J. , Hoffman Alex D. , Batterman Sharon L.
Published: May 2006

A mechanistic model for the uptake and elimination of ionizable organic chemicals at fish gills is presented. This model is a modification of a previous model for nonionizable organic chemicals that addressed the transport of chemical to and from gill surfaces in water and blood, diffusion of chemical across epithelial cells, and binding of chemical to components in water and blood. For ionizable chemicals, three additional processes are included. First, excretory products alter the pH at gill surfaces, affecting the relative amounts of neutral and ionized molecules compared with that in the bulk exposure water. Second, ionized molecules support chemical flux to and from epithelial cell membranes and help maintain high diffusion gradients of neutral molecules across these membranes, thereby contributing to uptake and elimination even if the membranes are impermeable to ionized molecules. Third, membrane barriers are not completely impermeable to ionized molecules, and even limited permeability can have appreciable effects on chemical flux. Approaches for model parameterization are discussed. Model-predicted relationships of uptake and elimination rates to exposure water pH, alkalinity, and chemical properties are presented and discussed in terms of model processes. The model is shown to predict important features of reported effects of pH on uptake rates of weak organic acids.
Uptake and elimination of ionizable organic chemicals at fish gills: II. Observed and predicted effects of pH, alkalinity, and chemical properties
Authors: Erickson Russell J. , McKim James M. , Lien Gregory J. , Hoffman Alex D. , Batterman Sharon L.
Published: May 2006

Effects of exposure-water pH on chemical uptake at rainbow trout (Oncorhynchus mykiss) gills were investigated for nine weakly acidic, chlorinated phenols with different ionization constants and hydrophobicities and for a moderately hydrophobic, nonionizable reference chemical (1,2,4-trichlorobenzene). Uptake rates for all chemicals varied little from pH 6.3 to 8.4, despite ionization of the chlorinated phenols ranging from less than 1 to greater than 99.9% among these pH values and chemicals. At pH 9.2, uptake rates were reduced substantially for the chlorinated phenols but not for the reference chemical. These results indicate greater bioavailability of neutral chemical forms but also considerable bioavailability of ionized forms that varies with pH. Three mechanisms were evaluated regarding such ionized chemical bioavailability. First, reduced pH at the gill surface causes net conversion of ionized molecules to more readily absorbed neutral molecules. This mechanism was tested by increasing exposure-water alkalinity, which increased gill surface pH and reduced uptake of the chlorinated phenols but not of the reference chemical. Magnitudes of these effects were close to predictions from a mathematical model for chemical exchange at fish gills that incorporated this mechanism. Second, ionized molecules contribute to uptake by maintaining high gradients of neutral molecules across epithelial membrane barriers, even if the barriers are impermeable to these ions. This mechanism was demonstrated to explain the similarity of uptake among pH values and chemicals at pH less than 8.4 and the degree to which uptake declined at pH 9.2. Third, membrane barriers can have some permeability to the ionized forms, but this was not important for the chemicals and conditions of the present study. Increased exposure-water pH also was demonstrated to increase elimination rates of these chemicals, which also was in accord with model expectations.