bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing ozone networks using positive matrix factorization
Authors: Rizzo Michael J. , Scheff Peter A. 
Published: June 2004

AbstractIn 2001, the United States Environmental Protection Agency (USEPA) began the process of examining the national monitoring networks to assess the contribution of individual monitoring sites in providing useful information to the public and regulatory agencies. One of the first networks to be examined was ozone, with the assessment being initially completed on a national level and then further refined on a regional basis. The goal of the regional analysis was to determine which monitors may be providing redundant information and could, therefore, be removed or relocated to another area in need of additional monitoring data.One technique which was used in the regional analysis of the ozone network was positive matrix factorization (PMF). This technique is similar to classical factor analysis, which allows for a series of related variables to be grouped into a smaller set of independent factors that represent combinations of the original variables. In addition to grouping the data into factors, this novel approach also provides predicted values of the analysis variable. Comparison of the predicted to the actual values not only gave an indication of how well the model fitted the ozone concentrations, but also aided in the determination of the information value of individual monitors.Hourly ozone data were polled from the USEPA's national data archive for a total of 24 states for the prime ozone formation months of May through September for 1996 to 2000. Daily maximum 8‐hour concentrations were calculated for each site according to the methods contained in 40 CFR Part 50 Appendix H. Because PMF requires a complete data record across all sites for all days analyzed, sites that were missing data were interpolated linearly over time.The results of the PMF analysis contained 10 factors representing various areas of the country including the Lake Michigan, Atlantic Coast, North Carolina, St. Louis/Indianapolis, Upper New York State, Ohio, Pennsylvania, Kansas/Southeast Missouri/Arkansas, Minnesota/Northwest Wisconsin, and Kentucky/Tennessee areas. Actual to predicted ratios were calculated for each day at each site and the coefficients of variation (CVs) of the individual ratio distributions were utilized as a metric to determine which sites were consistently being predicted well by PMF. Sites with low CVs were interpreted as being well predicted and considered not to be providing ambient ozone information as valuable as that provided by monitors that were poorly predicted by the model. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 110–119, 2004
Planning for the future—Development of action criteria that balance regulatory risks versus market and production requirements at an opthalmic lens coating facility
Authors: Hangal Sunil P. , Hober Michael J. , Sweeney Paul 
Published: June 2004

AbstractA growing ophthalmic coating facility based in Florida must plan for the future by balancing the risks associated with environmental regulatory requirements and production requirements based on market and business conditions. The lens coating operations at this facility utilize both volatile organic compounds and hazardous air pollutants. The type and quantity of coatings utilized relative to market demands for products in the future may potentially result in the facility exceeding major source thresholds under Title V of the Clean Air Act, thus requiring permit changes and, most likely, emissions controls. A description of the facility, as well as the environmental risks is presented relative to potential “responses” available for consideration under present production variations. An in‐depth analysis of the various options for compliance and control management as well as operational flexibility in order to meet business demands is provided. The evaluation includes options in becoming a major facility under Clean Air Act Title V requirements, application of Maximum Available Control Technology requirements, and options in managing chemical inventory and production techniques to avoid major source thresholds, if it is possible to do so. This analysis will establish the framework by which company management can implement a formal program with automatic response activities that are put into effect when facility emissions exceed preestablished thresholds. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 135–140, 2004
Efficient sampling techniques for uncertainties in risk analysis
Authors: Wang Renyou , Diwekar Urmila , Grégoire Padró Catherine E. 
Published: June 2004

AbstractRisk and policy analysis involves consideration of uncertainties. A quantitative probabilistic method for uncertainty analysis includes: (1) quantifying and assigning probabilistic distributions to the input uncertainties, (2) sampling the distributions of these uncertain parameters in an iterative fashion using Monte Carlo methods, (3) propagating the effects of uncertainties through the model, and (4) predicting the outcomes in terms of probabilistic measures like mean, variance, and fractiles. However, the results of the probabilistic analysis depend on the number of samples chosen. The sample size required for a particular analysis depends on various factors such as type of model, the random number generator used, type of distributions, and the output probabilistic measure and cannot be universally defined. The general tendency is to reduce the samples as much as possible without realizing the effect on decisions. For example, the mean of the output requires a number of samples that is an order of magnitude less compared to the variance. Therefore, it is desirable to use a sampling technique that can predict the output probabilistic measure accurately with the minimum number of samples. In this work, we present new sampling techniques based on Quasi‐Monte Carlo sequences and Latin hypercube sampling. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 141–157, 2004
Walking pathways toward becoming a culturally competent evaluator: Boundaries, borderlands, and border crossings
Authors: Symonette Hazel 
Published: June 2004

AbstractThis chapter shares insights derived from one practitioner's continuing journey toward excellence in mainstreaming culturally responsive evaluation processes, practices, and products. Evaluation's intrinsic value as a self‐diagnostic resource for critical and creative reflection, empowered self‐improvement, and strategic image management is spotlighted.
A finite volume unstructured multigrid method for efficient computation of unsteady incompressible viscous flows
Authors: Tai Chin Hoe , Zhao Yong 
Published: June 2004

AbstractAn unstructured non‐nested multigrid method is presented for efficient simulation of unsteady incompressible Navier–Stokes flows. The Navier–Stokes solver is based on the artificial compressibility approach and a higher‐order characteristics‐based finite‐volume scheme on unstructured grids. Unsteady flow is calculated with an implicit dual time stepping scheme. For efficient computation of unsteady viscous flows over complex geometries, an unstructured multigrid method is developed to speed up the convergence rate of the dual time stepping calculation. The multigrid method is used to simulate the steady and unsteady incompressible viscous flows over a circular cylinder for validation and performance evaluation purposes. It is found that the multigrid method with three levels of grids results in a 75% reduction in CPU time for the steady flow calculation and 55% reduction for the unsteady flow calculation, compared with its single grid counterparts. The results obtained are compared with numerical solutions obtained by other researchers as well as experimental measurements wherever available and good agreements are obtained. Copyright © 2004 John Wiley & Sons, Ltd.
Arginine deiminase enhances dexamethasone‐induced cytotoxicity in human T‐lymphoblastic leukemia CCRF‐CEM cells
Authors: Noh Eun‐Joo , Kang Sang‐Wook , Shin Yong‐Jae , Choi Sang‐Hyun , Kim Chan‐Gil , Park In‐Sun , Wheatley Denys N. , Min Bon‐Hong 
Published: June 2004

AbstractSince arginine deiminase (ADI; EC 3.5.3.6) inhibits cell proliferation by arresting cells in the G1phase, we tested its synergistic effect on cell death induced by dexamethasone (DEX), which also induces apoptosis by G1cell cycle arrest. ADI inhibited cell proliferation and induced apoptosis in human leukemic CEM cells in a dose‐dependent manner. Simultaneous treatment with ADI and DEX showed synergistic effects on DNA fragmentation and LDH release. In addition, ADI exerted its anti‐proliferative activity against DEX‐resistant CEM cells. ADI suppressed expression of c‐myc, a potential key regulator of cell proliferation and apoptosis, and increased expression of p27Kip1cyclin‐dependent kinase inhibitor. These results suggest that ADI efficiently increases the anti‐cancer effect of DEX on human leukemic CEM cells through G1cell cycle arrest involving downregulation of c‐myc and upregulation of p27Kip1. © 2004 Wiley‐Liss, Inc.
PTEN promoter is methylated in a proportion of invasive breast cancers
Authors: Khan Salma , Kumagai Takashi , Vora Jaimini , Bose Namrata , Sehgal Indu , Koeffler Phillip H. , Bose Shikha 
Published: June 2004

AbstractThe PTEN protein is a negative regulator of the Akt pathway, leading to suppression of apoptosis and increased cell survival. Its role as a tumor‐suppressor gene has been adequately substantiated, and homozygous mutations have been demonstrated in familial and sporadic cancers. In breast cancers, expression of PTEN protein is lost/reduced in 38% of cases. Somatic mutations are, however, rarely found. Our study was therefore designed to determine if differential methylation of the PTEN promoter region has a role in the transcriptional inactivation of the gene in invasive breast carcinomas. A total of 44 samples of invasive human breast cancer, 5 breast cancer cell lines and 16 samples of normal human breast tissue from young and elderly women were studied for methylation of the PTEN promoter by methylation‐specific PCR and PTEN protein expression by immunohistochemistry. PTEN methylation occurred in 34% of breast cancers, and 60% of these samples were associated with loss of PTEN protein. Analyzed from a different perspective, 34% of breast cancers had reduced expression of PTEN and 60% had a methylated PTEN promoter. None of the breast cancer cell lines and normal breast tissues showed methylation. In summary, methylation of the PTEN promoter leads to PTEN inactivation in a subset of human breast cancers. © 2004 Wiley‐Liss, Inc.
An investigation of mammographic density and gene variants in healthy women
Authors: Maskarinec Gertraud , Lurie Galina , Williams Andrew E. , Le Marchand Loic 
Published: June 2004

AbstractThis cross‐sectional study examined if polymorphisms in genes that code for enzymes involved in the production and metabolism of estrogens are associated with mammographic density, a strong predictor of breast cancer risk. The study included 328 healthy women of different ethnicities who underwent mammographic screening and donated a blood or mouthwash sample for DNA analysis. After digitizing cranio‐caudal views of the mammograms, we performed computer‐assisted mammographic density assessment. Following DNA extraction, samples were analyzed for polymorphisms in theCOMT(Val158Met),CYP1A1(Ile462Val),CYP1B1(Val432Leu),CYP1A2(*1F) andCYP17(T27C) genes using PCR‐RFLP. Breast density was lower in Caucasians than in Asians. Caucasian women were less likely to carry theCYP1A1variant allele and more likely to carry the variant alleles forCYP1B1andCOMTthan women with Asian or Hawaiian ancestry. The low‐activityCOMTandCYP1A2variant alleles were weakly related to lower percent mammographic density after adjustment for age, ethnicity, body mass index and reproductive variables (pfor gene‐dosage effect = 0.08 and 0.05, respectively). These relations were observed in premenopausal women only and were similar in direction and magnitude after stratification by ethnicity. We found no significant associations between breast density and the variant alleles forCYP1A1, CYP1B1andCYP17.Our data suggest lower mammographic density for women carrying theCOMTandCYP1A2variant alleles than for women carrying the common alleles, though this is the opposite of what is commonly hypothesized from the enzyme function. © 2004 Wiley‐Liss, Inc.
Bioassessment of Selected Inland Water Bodies in Sri Lanka Using Benthic Oligochaetes with Consideration of Temporal Variations
Authors: Pathiratne Asoka , Weerasundara Ajith 
Published: June 2004

AbstractThe organic pollution status of three inland water bodies in Sri Lanka was evaluated using benthic oligochaete communities with the environmental characteristics considering temporal variation over one year period. Oligochaete species richness and abundance was consistently higher in the highly eutrophic and organically polluted Lake Beira in comparison with the less polluted water bodies. In a cluster analysis of oligochaete community compositions, the assemblages grouped by the water bodies rather than by months. Principal component analysis revealed that the structure of the oligochate community was mainly influenced by conductivity, nitrate, biochemical oxygen demand levels of water and organic carbon content of the sediment. In the ordination, the polluted Lake Beira separated from the other water bodies along the first axis. The results revealed that there could be a potential for using benthic oligochaetes for bioassessment of inland water bodies in Sri Lanka. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental Study on the Diet of Mosquitofish (Gambusia holbrooki) under Different Ecological Conditions in a Shallow Lake
Authors: Blanco Saúl , Romo Susana , Villena María‐José 
Published: June 2004

AbstractWe studied the diet of the eastern mosquitofish Gambusia holbrooki with in situ experimental mesocosms located in a shallow lake. Different nutrient concentrations (phosphorus and nitrogen) and fish population densities were tested. Our results confirm that it is a planktivorous species, with also a great ingestion of algae and detritus. Nutrient fertilization caused almost no changes in this species feeding behavior, but larger mosquitofish stocks induced a shift to zooplanktivory and a decline in detritivory. When macrophytes were present, the predation effect focused on zooplankton and plant‐associated animals, otherwise predation on bottom macroinvertebrates increased. Females preyed upon almost all groups more intensely, including detritus. Males and juveniles did not overlap diet, the former being more selective on ostracods, while juveniles consumed detritus, rotifers and cladoceran. Our data support the idea that mosquitofish can cause important top‐down effects in shallow lakes under a wide variety of ecological conditions, being an important zooplanktivore in both turbid and plant‐dominated shallow lakes especially in the Mediterranean zone, where high temperatures and absence of piscivores promote maintenance of its populations during the whole year. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Effects of Zebra Mussels (Dreissena polymorpha) on the Foraging Success of Eurasian Perch (Perca fluviatilis) and Ruffe (Gymnocephalus cernuus)
Authors: Dieterich Axel , Mörtl Martin , Eckmann Reiner 
Published: June 2004

AbstractComplex habitat structures can influence the foraging success of fish. Competition for food between fish species can therefore depend on the competitors' abilities to cope with structural complexity. In laboratory experiments, we comparatively assessed effects of zebra mussels (Dreissena polymorpha Pall.) on the foraging success of Eurasian perch (Perca fluviatilis L.) and ruffe (Gymnocephalus cernuus (L.)). In single‐species and mixed‐species experiments, the fish were fed caddisfly larvae (Tinodes waeneri (L.)) over complex (mussel‐covered stones) and less‐complex (bare stones) substrates. With intraspecific competition, food consumption by perch and ruffe decreased significantly when the complex substrate was used. With interspecific competition, food consumption by perch and ruffe did not change with substrate complexity, but perch clearly out‐competed ruffe on both substrates. Zebra mussel beds provide a refuge for macrozoobenthos against predation by ruffe and probably also by perch. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental Analysis of Grazing by the Mayfly Meridialaris chiloeensis on Different Successional Stages of Stream Periphyton
Authors: Díaz Villanueva Verónica , Modenutti Beatriz 
Published: June 2004

AbstractIn this study we determined grazing effects of the South Andean endemic mayfly Meridialaris chiloeensis on periphyton at different stages of successional development. Grazing effects were studied through a two‐factor experimental design (colonization stages X grazer density) in a stream‐side channel in spring and winter. Our results showed an absence of proportionality between grazer density and periphyton decline in response to grazers at low and intermediate levels of periphytic biomass; however, when periphyton biomass was high a direct inverse relationship was observed between post‐grazing biomass and grazer density. The relationship between periphytic algae (chlorophyll a concentration) and periphyton (total periphytic ash‐free dry mass) (C/OM index) was used as an estimation of the autotrophic fraction in the total periphyton matrix. Grazing did not alter the C/OM index indicating that both autotrophic and heterotrophic fractions of the periphyton components were reduced in the same proportion. Ordination of samples using the relative abundance of diatom species showed that herbivore effect was less evident at intermediate and late stage of colonization than at early one. These results support the statement that the outcome of the herbivore‐periphyton interaction may depend on the successional stage of the periphyton community. In spring Fragilaria pinnata relative abundance, on the basis of cell counts, was reduced by grazing and Nitzschia palea was enhanced. In the winter experiment, grazing decreased Achnanthes minutissima relative abundance. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pelagic Ciliates in a Large Mesotrophic Lake: Seasonal Succession and Taxon‐Specific Bacterivory in Lake Constance
Authors: Cleven Ernst‐Josef 
Published: June 2004

AbstractThe taxonomic composition of the ciliate assemblage and their taxon‐specific bacterial grazing rates in Lake Constance were investigated over the course of one year. Bacterial grazing rates were measured using natural fluorescently labelled bacteria (FLB) and compared to bacterial production. Small species such as Balanion planctonicum/Urotricha furcata and Rimostrombidium spp./Halteria sp. were the most numerous ciliates on the annual average. Larger ciliates such as Rimostrombidium lacustris and Limnostrombidium spp. contributed significantly to total ciliate biomass, but were relatively unimportant as bacterial grazers. Per capita ingestion rates ranged from 0–194 bacteria ciliate−1 h−1 and changed seasonally up to a hundredfold within a given taxon. Approximately 1% of the bacterial production were removed by the ciliate community on the annual average. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Colonization by Macroinvertebrates of Experimentally Disturbed Stones in Three Tropical Streams Differing in Size
Authors: Melo Adriano Sanches , Froehlich Claudio Gilberto 
Published: June 2004

AbstractWe experimentally disturbed stones in three streams of different sizes and followed the macroinvertebrate colonization process in terms of abundance, species richness and similarity over 64 days. We hypothesized that colonization in the smallest and in the largest streams would be slower than in the medium‐sized stream. The small upstream pool of colonists available in the smallest stream could restrict colonization, while in the largest stream predation by the diverse fish assemblage could restrict drifting colonists. The medium‐sized stream did not have these two constraints. We found similar colonization patterns in all three streams, leading to the rejection of the stated hypotheses. Lack of support of the original hypothesis might be due to the weakness of the two hypothesized restrictions on colonization. In addition, colonization by crawling species from undisturbed nearby patches might be of significant importance. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diel Variations in the Vertical Distribution of Crustacean Zooplankton and Food Selection by Planktivorous Fish in a Shallow Turbid Lake
Authors: Alajärvi Erika , Horppila Jukka 
Published: June 2004

AbstractThe variations in the vertical migrations by zooplankton and food composition of fish in the shallow, clay‐turbid Mustionselkä basin of Lake Hiidenvesi were studied (water depth 3 m). Daphnids showed signs of reverse migration, their density in the surface layer being highest during the day. The reverse migration was probably due to predation threat by the predatory cladoceran Leptodora kindtii. Chydorus sphaericus, which was consumed especially by the day active bleak (Alburnus alburnus), showed normal vertical migration. Copepods showed no clear vertical movements. Leptodora kindtii, as well as the large herbivore Limnosida frontosa, showed no vertical migrations, but their overall abundance increased considerably during the night, indicating horizontal movement towards the open water at night. Due to the shallowness of the water, vertical migrations may not be a good predator‐avoidance strategy for the largest cladocerans, which may be able to perform horizontal migrations. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bone response to a novel highly porous surface in a canine implantable chamber
Authors: Frenkel Sally R. , Jaffe William L. , Dimaano Fred , Iesaka Kazuho , Hua Tian 
Published: June 2004

AbstractLong‐term survival of uncemented hip components is dependent upon successful biological fixation. This study examined a new prosthetic surface treatment consisting of a highly porous open structure of commercially pure titanium, Tritanium™ Dimensionalized Metal; its overall porosity is approximately 65–70%. With the use of an implantable chamber in dogs, the effects of this treatment on bone ingrowth and strength of attachment were compared to both titanium (overall porosity of 30–35%) and cobalt chrome beads (overall porosity of 35–40%), with and without hydroxyapatite coating. At 6 and 12 weeks, chambers were explanted and specimens underwent high‐resolution radiographic imaging and mechanical testing. At 12 weeks, Tritanium surfaces had greater bone penetration and tensile strength than remaining surface types. Over 40% of the Tritanium specimens had a tensile strength greater than 500 N, exceeding the testing capability of the servohydraulic equipment. The highly porous Tritanium surfaces allow for a far greater amount of bone ingrowth than beaded surfaces, and may create a geometry that enhances mechanical strength. Tritanium™ Dimensionalized Metal surface treatment may result in a clinically valuable implant fixation surface to induce rapid ingrowth and a strong bone–implant interface, contributing to increased implant survivorship. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 387–391, 2004