bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Cause of Deafness Influence Outcome After Cochlear Implantation in Children?
Authors: Nikolopoulos Thomas P. , Archbold Sue M. , O'Donoghue Gerard M.
Published: October 2006

OBJECTIVES. The objective of this study was to evaluate long-term speech perception abilities of comparable groups of postmeningitic and congenitally deaf children after cochlear implantation.

METHODS. This prospective longitudinal study comprised 46 postmeningitic deaf children and 83 congenitally deaf children with age at implantation of ≤5.6 years. Both groups were comparable with respect to educational setting and mode of communication and included children with additional disabilities.

RESULTS. Both postmeningitic and congenitally deaf children showed significant progress after implantation. Most (73% and 77%, respectively) could understand conversation without lip-reading or use the telephone with a known speaker 5 years after implantation, whereas none could do so before implantation. At the same interval, the postmeningitic and congenitally deaf children scored a mean open-set speech perception score of 47 (range: 0–91) and 46 (range: 0–107) words per minute, respectively, on connected discourse tracking. The respective mean scores at the 3-year interval were 22 and 29 correct words per minute, respectively. None of these children could score a single correct word per minute before implantation. The progress in both groups was statistically significant. When the 2 groups were compared, there was no statistically significant difference.

CONCLUSION. Postmeningitic and congenitally deaf children showed significant improvement in their auditory receptive abilities at the 3- and 5-year intervals after cochlear implantation. There was no statistically significant difference between the outcomes of the 2 groups, suggesting that, provided that children receive an implant early, cause of deafness has little influence on outcome. Although the prevalence of other disabilities was similar in both groups, for individual children, their presence may have profound impact. The study supports the concept of implantation early in life, irrespective of the cause of deafness.
Clinical and Education Workload Measurements Using Personal Digital Assistant–Based Software
Authors: MacGregor Daune L. , Tallett Susan , MacMillan Sharon , Gerber Richard , O'Brodovich Hugh
Published: October 2006

OBJECTIVE. There are no accepted and practical measures of the relative clinical and educational activities of pediatricians who work in an academic health science center. Such measures are necessary for justification of existing and future human resource plans and evaluation of the activities and performance of physicians. The limited literature on the measurement of physician workload usually focuses on a specific subspecialty group and does not account for such issues as indirect patient care, such as telephone calls or e-mail consultations; variables that affect the delivery of clinical care, including patient acuity and complexity; and the presence of students during the patient care activities. After completing a pilot study that assessed the educational workload of faculty members, we adapted existing personal digital assistant technology and software to document clinical and educational activities.

METHODS. Twenty full-time physicians from 4 subspecialty pediatric divisions participated in a 2-week evaluation project in May through June 2005. Clinical activities, with and without trainees, and educational activities were collected with the use of personal digital assistants. Software allowed an individualized division-specific drop-down menu. Information that was collected included clinical (location of activity, diagnosis, and time requirement) and educational activities. After completion of a 2-week data collection period, each physician was asked to complete a 5-question evaluation form.

RESULTS. The project was completed successfully with capture of additional clinical and educational activities. A 5-question evaluation form was completed by 70% of the participants at the end of the 2-week data collection. Data on clinical and educational activities were analyzed qualitatively and graphed.

CONCLUSIONS. This method of workload data collection added significant information in capturing activities that are not measured in traditional workload evaluations for either clinical activities, such as e-mail, telephone, and patient information review, or educational endeavors, including mentoring and educational lectures and presentations.
Rethinking Well-Child Care in the United States: An International Comparison
Authors: Kuo Alice A. , Inkelas Moira , Lotstein Debra S. , Samson Kyra M. , Schor Edward L. , Halfon Neal
Published: October 2006

BACKGROUND. The increasing scope of health supervision recommendations challenges well-child care delivery in the United States. Comparison of the United States with other countries’ delivery systems may highlight different assumptions as well as structural approaches for consideration.

OBJECTIVE. Our goal was to describe the process of well-child care delivery in industrialized nations and compare it to the US model of child health care.

METHODS. Literature reviews and international experts were used to identify 10 countries with unique features of well-child care delivery for comparison to the United States. Key-informant interviews using a structured protocol were held with child health experts in 10 countries to delineate the structural and practice features of their systems. Site visits produced additional key informant data from 5 countries (Netherlands, England, Australia, Sweden, and France).

RESULTS. A primary care framework was adapted to analyze structural and practice features of well-child care in the 10 countries. Although well-child care content is similar, there are marked differences in the definitions of well-child care and the scope of practice of primary care professionals and pediatricians specifically who provide this care across the 10 countries. In contrast to the United States, none of the countries place all well-child care components under the responsibility of a single primary care provider. Well-child care services and care for acute, chronic, and behavioral/developmental problems are often provided by different clinicians and within different service systems.

CONCLUSIONS. Despite some similarities, well-child care models from other countries differ from the United States in key structural features on the basis of broad financing differences as well as specific visions for effective well-child care services. Features of these models can inform child health policy makers and providers in rethinking how desired improvements in US well-child care delivery might be sought.
Hemodynamic Changes After Low-Dosage Hydrocortisone Administration in Vasopressor-Treated Preterm and Term Neonates
Authors: Noori Shahab , Friedlich Philippe , Wong Pierre , Ebrahimi Mahmood , Siassi Bijan , Seri Istvan
Published: October 2006

OBJECTIVE. We sought to investigate whether the increase in blood pressure and decrease in vasopressor support after hydrocortisone administration are associated with changes in systemic hemodynamics in neonates who receive high-dosage dopamine to maintain blood pressure at the lowest acceptable levels.

METHODS. In this prospective, observational study, preterm and term neonates who required dopamine ≥15 μg/kg per minute to maintain minimum acceptable blood pressure received intravenous hydrocortisone 2 mg/kg followed by up to 4 doses of 1 mg/kg every 12 hours. Fifteen preterm and 5 term neonates without a patent ductus arteriosus composed the study population. Echocardiograms and vascular Doppler studies were performed immediately before the first dose of hydrocortisone and at 1, 2, 6 to 12, 24, and 48 hours thereafter.

RESULTS. In the 15 preterm infants, during the first 12 hours of hydrocortisone treatment, the 28% increase in blood pressure paralleled that in the systemic vascular resistance without changes in stroke volume or cardiac output, whereas dopamine dosage decreased. By 24 hours, the dosage of dopamine continued to decrease, whereas stroke volume increased without additional changes in systemic vascular resistance. By 48 hours, dopamine dosage decreased by 72%; blood pressure and stroke volume increased by 31% and 33%, respectively; and systemic vascular resistance and cardiac output tended to be higher (14% and 21%, respectively) compared with baseline. Contractility, global myocardial function, and Doppler indices of blood flow in the middle cerebral and renal artery remained normal and unchanged. The findings in the 5 term infants showed a similar pattern for changes in cardiac function, systemic hemodynamics, and organ blood flow after hydrocortisone administration.

CONCLUSIONS. In preterm and term neonates who require high-dosage dopamine to maintain blood pressure at the lowest acceptable levels, hydrocortisone improves blood pressure without compromising cardiac function, systemic perfusion, or cerebral and renal blood flow.
Evaluation of Potentially Common Adverse Events Associated With the First and Second Doses of Measles-Mumps-Rubella Vaccine
Authors: LeBaron Charles W. , Bi Daoling , Sullivan Bradley J. , Beck Carol , Gargiullo Paul
Published: October 2006

BACKGROUND/OBJECTIVES. In 1989, the American Academy of Pediatrics and the Advisory Committee on Immunization Practices recommended that school children receive 2 doses of measles-mumps-rubella vaccine. With measles and rubella eliminated from the United States, measles-mumps-rubella vaccine adverse events have come under scrutiny, but no study has compared the reactogenicity of the first (measles-mumps-rubella vaccine dose 1) and second (measles-mumps-rubella vaccine dose 2) doses at the most common ages of administration in the United States.

METHODS. From a health maintenance organization, 3 groups of children were recruited: (1) toddlers aged 12 to 24 months receiving measles-mumps-rubella vaccine dose 1; (2) kindergartners aged 4 to 6 years receiving measles-mumps-rubella vaccine dose 2; and (3) middle schoolers aged 10 to 12 years receiving measles-mumps-rubella vaccine dose 2. From 2 weeks before measles-mumps-rubella vaccine administration until 4 weeks afterward, families recorded in diaries the occurrence of potentially common symptoms. Postvaccination symptom rates were compared with the prevaccination baseline, with significance assessed by testing incidence rate ratios estimated by Poisson regression.

RESULTS. Of 2173 children enrolled, 373 (17%) were lost to attrition, producing a study population of 1800. Compared with the prevaccination baseline, rates of fever, diarrhea, and rash were significantly elevated postvaccination among 535 toddlers receiving measles-mumps-rubella vaccine dose 1. An estimated net 95 (18%) experienced measles-mumps-rubella vaccine-associated events (median onset 5–10 days postvaccination, duration 2–5 days), with high fever (temperature ≥39.5°C) occurring in 33 (6%). None required medical attention. For 633 kindergartners and 632 middle schoolers, symptom rates were not significantly elevated after measles-mumps-rubella vaccine dose 2 compared with baseline.

CONCLUSIONS. Vaccination-associated adverse events occur in ∼1 of every 6 toddlers receiving measles-mumps-rubella vaccine dose 1, with high fever occurring in 1 of 20. Adverse events are infrequent for measles-mumps-rubella vaccine dose 2 administered to school-aged children.
Near Elimination of Hepatitis B Virus Infections Among Hawaii Elementary School Children After Universal Infant Hepatitis B Vaccination
Authors: Perz Joseph F. , Elm Joseph L. , Fiore Anthony E. , Huggler Janice I. , Kuhnert Wendi L. , Effler Paul V.
Published: October 2006

OBJECTIVES. Hawaii implemented routine infant hepatitis B vaccination in 1992 and required it for school entry in 1997. Previously, in 1989, a serologic survey among Hawaii school children in grades 1 to 3 indicated that 1.6% had chronic hepatitis B virus infection, and 2.1% had resolved infection. We conducted a follow-up survey to examine changes in hepatitis B virus infection rates.

PATIENTS AND METHODS. This study was performed in Oahu, Hawaii, during the 2001–2002 school year among children in grades 2 and 3. Consenting parents/guardians provided demographic information including place of birth. Participants were tested for serologic evidence of hepatitis B virus infection and their vaccination status was determined by reviewing school records. Rates of symptomatic acute hepatitis B among persons aged ≤19 years were calculated from cases reported from Hawaii to the Centers for Disease Control and Prevention between 1990 and 2004.

RESULTS. Completed hepatitis B vaccination series were documented for 83% of the 2469 participants by age 18 months and for 97% by age 5 years. Past or present hepatitis B virus infection was detected among 6 participants (0.24%), including 1 (0.04%) with chronic infection and 5 (0.20%) with resolved infections. Compared with the 1989 survey, these prevalences represent declines of 97% and 90% in chronic and resolved hepatitis B virus infections, respectively. The incidence of symptomatic acute hepatitis B in Hawaii children and adolescents aged ≤19 years decreased from 4.5 cases per 100000 in 1990 to 0.0 during 2002–2004. To date, the last reported case in a child aged <15 years in Hawaii occurred in 1996.

CONCLUSIONS.. Hepatitis B virus infection has nearly been eliminated in Hawaii children born after universal infant hepatitis B vaccination was implemented. These findings suggest that hepatitis B prevention goals are being met through routine immunization and related prevention programs among US children.
Payments to Children and Adolescents Enrolled in Research: A Pilot Study
Authors: Iltis Ana S. , DeVader Shannon , Matsuo Hisako
Published: October 2006

OBJECTIVES. The goal was to identify current payment practices in research involving children.

METHODS. A 4-page survey was mailed to the first author or corresponding author of pediatric research studies. Questions concerned whether children enrolled in research and/or their parents received any form of payment, values and types of remuneration, federal categories of pediatric research under which studies were approved, institutional policies regarding payments to children and/or their parents, institutional review board review of payment plans, factors that influenced payment decisions, prorating of payments, purposes of payments, perceived effects of payments on recruitment, and investigators' attitudes toward payments and the perceived risks and discomforts of studies.

RESULTS. Payment practices varied, and the reasons for which investigators adopted particular payment practices varied. Approximately one half offered payment. The most popular form of payment was cash. The number of institutions with policies addressing directly payments for children enrolled in research has increased, but still only approximately one half of institutions studied had such policies in place.

CONCLUSIONS. Awareness of the variations in payment practices and policies and additional study of the ethical issues surrounding payments for research participation are essential for building consensus and developing the guidelines the Institute of Medicine has said are necessary. Additional research also is needed to understand why parents enroll their children in research, how payments affect research participation decisions, and what the relationship between a study's risks and discomforts and payment should be.
The Contribution of Preterm Birth to Infant Mortality Rates in the United States
Authors: Callaghan William M. , MacDorman Marian F. , Rasmussen Sonja A. , Qin Cheng , Lackritz Eve M.
Published: October 2006

OBJECTIVE. Although two thirds of infant deaths in the United States occur among infants born preterm (<37 weeks of gestation), only 17% of infant deaths are classified as being attributable to preterm birth with the standard classification of leading causes of death. To address this apparent discrepancy, we sought to estimate more accurately the contribution of preterm birth to infant mortality rates in the United States.

METHODS. We identified the top 20 leading causes of infant death in 2002 in the US linked birth/infant death file. The role of preterm birth for each cause was assessed by determining the proportion of infants who were born preterm for each cause of death and by considering the biological connection between preterm birth and the specific cause of death.

RESULTS. Of 27970 records in the linked birth/infant death file for 2002, the 20 leading causes accounted for 22273 deaths (80% of all infant deaths). Among infant deaths attributable to the 20 leading causes, we classified 9596 infant deaths (34.3% of all infant deaths) as attributable to preterm birth. Ninety-five percent of those deaths occurred among infants who were born at <32 weeks of gestation and weighed <1500 g, and two thirds of those deaths occurred during the first 24 hours of life.

CONCLUSIONS. On the basis of this evaluation, preterm birth is the most frequent cause of infant death in the United States, accounting for at least one third of infant deaths in 2002. The extreme prematurity of most of the infants and their short survival indicate that reducing infant mortality rates requires a comprehensive agenda to identify, to test, and to implement effective strategies for the prevention of preterm birth.
Follow-up of a Randomized, Placebo-Controlled Trial of Postnatal Dexamethasone: Blood Pressure and Anthropometric Measurements at School Age
Authors: Washburn Lisa K. , Nixon Patricia A. , O'Shea T. Michael
Published: October 2006

OBJECTIVE. The purpose of this work was to evaluate the effects of a 42-day tapering course of dexamethasone on blood pressure and anthropometric measurements in school-age children who were born with very low birth weight.

METHODS. Sixty-eight children, who as neonates participated in a randomized placebo-controlled trial of a 42-day tapering course of dexamethasone (n = 38, dexamethasone; n = 30, placebo) to facilitate weaning from the ventilator, were seen at a median of 9 years of age. Participants underwent measurements of systolic blood pressure, diastolic blood pressure, mid-arm circumference, triceps skinfold thickness, height, and weight. Mann-Whitney U tests were used to compare groups, and Spearman coefficients were used to examine correlations between variables.

RESULTS. Comparing dexamethasone- and placebo-treated children, we found no differences in systolic blood pressure, mid-arm circumference, triceps skinfold thickness, height, weight, or body mass index. Twenty-nine percent of all subjects had systolic blood pressure and/or diastolic blood pressure ≥90th percentile for age and gender. Thirty percent of all subjects had body mass index ≥85th percentile for age and gender.

CONCLUSIONS. In a group of preterm very low birth-weight infants at high risk for chronic lung disease, we found no effects of dexamethasone on blood pressure or anthropometric measurements at 8 to 11 years of age. Of concern is that a high proportion in this sample had blood pressure ≥90th percentile and/or body mass index ≥85th percentile.
Prevention of Sexual Harassment in the Workplace and Educational Settings
Authors:   Committee on Pediatric Workforce
Published: October 2006

This Policy Statement was reaffirmed May 2009, October 2014, May 2017, and October 2019.

The American Academy of Pediatrics is committed to working to ensure that workplaces and educational settings in which pediatricians spend time are free of sexual harassment. The purpose of this statement is to heighten awareness and sensitivity to this important issue, recognizing that institutions, clinics, and office-based practices may have existing policies.
Child Life Services
Authors:   Child Life Council,   Committee on Hospital Care
Published: October 2006

Child life programs have become standard in most large pediatric centers and even on some smaller pediatric inpatient units to address the psychosocial concerns that accompany hospitalization and other health care experiences. The child life specialist focuses on the strengths and sense of well-being of children while promoting their optimal development and minimizing the adverse effects of children’s experiences in health care or other potentially stressful settings. Using play and psychological preparation as primary tools, child life interventions facilitate coping and adjustment at times and under circumstances that might prove overwhelming otherwise. Play and age-appropriate communication may be used to (1) promote optimal development, (2) present information, (3) plan and rehearse useful coping strategies for medical events or procedures, (4) work through feelings about past or impending experiences, and (5) establish therapeutic relationships with children and parents to support family involvement in each child’s care, with continuity across the care continuum. The benefits of this collaborative work with the family and health care team are not limited to the health care setting; it may also optimize reintegration into schools and the community.
A PRELIMINARY ANALYSIS OF TEACHING IMPROVISATION WITH THE PICTURE EXCHANGE COMMUNICATION SYSTEM TO CHILDREN WITH AUTISM
Authors: Marckel Julie M. , Neef Nancy A. , Ferreri Summer J.
Published: October 2006

Two young boys with autism who used the picture exchange communication system were taught to solve problems (improvise) by using descriptors (functions, colors, and shapes) to request desired items for which specific pictures were unavailable. The results of a multiple baseline across descriptors showed that training increased the number of improvised requests, and that these skills generalized to novel items, and across settings and listeners in the natural environment.
THE IMPACT OF HIGH‐ AND LOW‐PREFERENCE STIMULI ON VOCATIONAL AND ACADEMIC PERFORMANCES OF YOUTHS WITH SEVERE DISABILITIES
Authors: Graff Richard B. , Gibson Lenwood , Galiatsatos G. Tracey
Published: October 2006

Pictorial and tangible paired‐stimulus preference assessments were compared with 4 adolescents with developmental disabilities. In the tangible assessment, two stimuli were placed in front of the participant on each trial; in the pictorial assessment, two line drawings were placed in front of the participant on each trial. Approach responses were recorded for each assessment. The assessments generated similar preference hierarchies for all participants. Reinforcer assessments confirmed that response rates were higher when access to high‐preference items was available than when low‐preference items were available. Implications for assessing preferences and selecting items to be used in training programs are discussed.
TOWARD AN EMPIRICAL METHOD FOR IDENTIFYING MATCHED STIMULATION FOR AUTOMATICALLY REINFORCED BEHAVIOR: A PRELIMINARY INVESTIGATION
Authors: Rapp John T.
Published: October 2006

The effects of noncontingent matched stimulation (NMS) and response blocking on a boy's stereotypic behavior were evaluated using a multiple schedule that contained three 15‐min components (preintervention, intervention, and postintervention). Results showed that stereotypy was always higher after response blocking than before response blocking and was always lower after NMS than before NMS. These results suggest that response blocking may have produced deprivation for the product of stereotypy and that NMS may have provided stimulation that was similar to the product of stereotypy.
A COMPARISON OF INTERTEACHING AND LECTURE IN THE COLLEGE CLASSROOM
Authors: Saville Bryan K. , Zinn Tracy E. , Neef Nancy A. , Norman Renee Van , Ferreri Summer J.
Published: October 2006

Interteaching is a new method of classroom instruction that is based on behavioral principles but offers more flexibility than other behaviorally based methods. We examined the effectiveness of interteaching relative to a traditional form of classroom instruction—the lecture. In Study 1, participants in a graduate course in special education took short quizzes after alternating conditions of interteaching and lecture. Quiz scores following interteaching were higher than quiz scores following lecture, although both methods improved performance relative to pretest measures. In Study 2, we also alternated interteaching and lecture but counterbalanced the conditions across two sections of an undergraduate research methods class. After each unit of information, participants from both sections took the same test. Again, test scores following interteaching were higher than test scores following lecture. In addition, students correctly answered more interteaching‐based questions than lecture‐based questions on a cumulative final test. In both studies, the majority of students reported a preference for interteaching relative to traditional lecture. In sum, the results suggest that interteaching may be an effective alternative to traditional lecture‐based methods of instruction.
ESTABLISHING AND MAINTAINING TREATMENT EFFECTS WITH LESS INTRUSIVE CONSEQUENCES VIA A PAIRING PROCEDURE
Authors: Vorndran Christina M. , Lerman Dorothea C.
Published: October 2006

The generality and long‐term maintenance of a pairing procedure designed to improve the efficacy of less intrusive procedures were evaluated for the treatment of problem behavior maintained by automatic reinforcement exhibited by 2 individuals with developmental disabilities. Results suggested that a less intrusive procedure could be established as a conditioned punisher by pairing it with an effective punisher contingent on problem behavior. Generalization across multiple therapists was demonstrated for both participants. However, generalization to another setting was not achieved for 1 participant until pairing was conducted in the second setting. Long‐term maintenance was observed with 1 participant in the absence of further pairing trials. Maintenance via intermittent pairing trials was successful for the other participant.
A DERIVED TRANSFER OF SIMPLE DISCRIMINATION AND SELF‐REPORTED AROUSAL FUNCTIONS IN SPIDER FEARFUL AND NON‐SPIDER‐FEARFUL PARTICIPANTS
Authors: Smyth Sinéad , Barnes‐Holmes Dermot , Forsyth John P.
Published: October 2006

Two experiments investigated the derived transfer of functions through equivalence relations established using a stimulus pairing observation procedure. In Experiment 1, participants were trained on a simple discrimination (A1+/A2‐) and then a stimulus pairing observation procedure was used to establish 4 stimulus pairings (A1‐B1, A2‐B2, B1‐C1, B2‐C2). Subsequently, a transfer of the simple discrimination functions through equivalence relations was observed (e.g., C1+/C2‐). These procedures were modified in Experiment 2, which demonstrated that spider‐fearful and non‐spider‐fearful participants show differing levels of a transfer of self‐reported arousal functions for stimuli used in equivalence relations with video‐based material depicting scenes with spiders. The results demonstrate that the stimulus pairing observation procedure provides a viable alternative to matching‐to‐sample, and also offer tentative support for a derived‐relations model of the acquisition of anxiety responses in at least one sub‐clinical population.
MATCHING AND CONDITIONED REINFORCEMENT RATE
Authors: Shahan Timothy A. , Podlesnik Christopher A. , Jimenez‐Gomez Corina
Published: October 2006

Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative conditioned reinforcement rate. In the absence of observing responses, unsignaled periods of food delivery on a variable‐interval 90‐s schedule alternated with extinction on a center key (i.e., a mixed schedule was in effect). Two concurrently available observing responses produced 15‐s access to a stimulus differentially associated with the schedule of food delivery (S+). The relative rate of S+ deliveries arranged by independent variable‐interval schedules for the two observing responses varied across conditions. The relation between the ratio of observing responses and the ratio of S+ deliveries was well described by the generalized matching law, despite the absence of changes in the rate of food delivery. In addition, the value of the S+ deliveries likely remained constant across conditions because the ratio of S+ to mixed schedule food deliveries remained constant. Assuming that S+ deliveries serve as conditioned reinforcers, these findings are consistent with the functional similarity between primary and conditioned reinforcers suggested by general choice theories based on the concatenated matching law (e.g., contextual choice and hyperbolic value‐added models). These findings are inconsistent with delay reduction theory, which has no terms for the effects of rate of conditioned reinforcement in the absence of changes in rate of primary reinforcement.
RAPID ACQUISITION IN CONCURRENT CHAINS: EVIDENCE FOR A DECISION MODEL
Authors: Grace Randolph C. , McLean Anthony P.
Published: October 2006

Pigeons' choice in concurrent chains can adapt to rapidly changing contingencies. Grace, Bragason, and McLean (2003) found that relative initial‐link response rate was sensitive to the immediacy ratio in the current session when one of the terminal‐link fixed‐interval schedules was changed daily according to a pseudorandom binary sequence (e.g., Schofield & Davison, 1997). The present experiment tested whether the degree of variation in delays across sessions had any effect on acquisition rate in Grace et al.‘s (2003) rapid‐acquisition procedure. In one condition (“minimal variation”), the left terminal link was always fixed‐interval 8 s and the right terminal link was either fixed‐interval 4 s or fixed‐interval 16 s. In the other condition (“maximal variation”), a unique pair of fixed‐interval values was used in each session. Responding was sensitive to the current‐session immediacy ratio in both conditions, but across subjects there was no systematic difference in sensitivity. These results challenge the view that initial‐link responding in the rapid‐acquisition procedure is determined by changes in the learned value of the terminal‐link stimuli, and suggests instead that a process resembling categorical discrimination may control performance. A decision model based on the assumption that delays are categorized as short or long relative to the history of delays provided a good account of the data and shows promise in being able to explain other choice phenomena.
Bagasse‐Assisted Bioremediation of Ammonia from Shrimp Farm Wastewater
Authors: Krishnani Kishore K. , Parimala V. , Gupta B. P. , Azad I. S. , Meng Xiaoguang , Abraham M.
Published: October 2006

Development of new economically feasible ecofriendly products from agricultural wastes or byproducts for shrimp farm wastewater treatment is the objective of our continued research. Ammonia is a nitrogenous toxicant, which is commonly found in wastewater from shrimp farms. In the present study, we explored the possibility of the use of simply and inexpensively prepared bagasse products so that this abundant crop byproduct could be used to remove ammonia from shrimp farm wastewater. Bagasse, a natural highly fibrous lignocellulosic byproduct of sugarcane, was converted into five different products. Experimental results have shown that ammonia is efficiently removed from wastewater by four bagasse products with a dose of 1 to 6 g/L within 24 hours. The effect of bagasse products on other water quality parameters and growth kinetics of biofilm bacteria onto bagasse fiber have also been studied. Efficacies of products were compared by using statistical analysis. Products developed from bagasse are useful and economical.
Computational Fluid Dynamics Analysis of the Effects of Reactor Configuration on Disinfection Efficiency
Authors: Greene Dennis J. , Haas Charles N. , Farouk Bakhtier
Published: October 2006

The efficacy of disinfection processes in water purification systems is governed by several key factors, including reactor hydraulics, disinfectant chemistry, and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics (CFD) model to predict velocity fields, mass transport, chlorine decay, and microbial inactivation in a continuous flow reactor. The CFD model was also used to evaluate disinfection efficiency in alternative reactor designs. The CFD reactor analysis demonstrates that disinfection efficiency is affected by both kinetics and mixing state (i.e., degree of micromixing or segregation). Residence time distributions (RTDs) derived from tracer analysis do not describe intrinsic mixing conditions. The CFD‐based disinfection models account for reactor mixing patterns by resolution of the reactor velocity field and thus provide a better prediction of microbial inactivation than models that use an RTD.
Treatment of Food Industry Waste by Bench‐Scale Upflow Anaerobic Sludge Blanket‐Anoxic‐Aerobic System
Authors: Gohil Alpesh , Nakhla George
Published: October 2006

An upflow anaerobic sludge blanket (UASB)‐anoxic‐aerobic system was used for treatment of tomato and bean processing wastewater. At various hydraulic retention times, ranging from 0.7 to 5 days, excellent removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), ammonia‐nitrogen (NH4‐N), and total Kjeldahl nitrogen was achieved with final effluent BOD/TSS/NH4‐N concentrations of less than 15/15/1 mg/L. Biogas yield in the UASB reactor varied from 0.33 to 0.44 m3/kgCODremoved. The kinetics of anaerobic treatment were investigated. The yield coefficient was 0.03 gVSS/gCOD; maximum specific growth rate was 0.24 day−1; Monod half velocity constant was 135 mgCOD/L; and specific substrate utilization rate was 3.25 gCOD/gVSS · d. Nitrification and denitrification kinetics were studied in batch experiments, and the rates were comparable with those in the continuous flow system.
Development of a Three‐Stage System for Wastewater Toxicity Monitoring: A Design and Feasibility Study
Authors: Ren Shijin , Frymier Paul D.
Published: October 2006

A three‐stage system was developed to automate a batchwise toxicity testing protocol designed for assessing wastewater toxicity to activated sludge. The three‐stage system used the luminescent bacterium Shk1. The three stages were cell storage, cell activation, and continuous toxicity testing. Shk1 cells were stored in a bioreactor at 4°C when the system was not in use and activated in another bioreactor for use in toxicity tests conducted in a continuous manner. The system could quickly be switched between the “off” and “on” modes, and operation of the system was easy. The stability of the system, in terms of cell density and bioluminescence in the storage and activation bioreactors, and the response of the activated cells to a metal and an organic toxicant were studied. The feasibility of the system design was demonstrated by simulating zinc toxicity episodes in synthetic wastewater. The needs for further modifications and improvements of the system were discussed.
Detection of Cryptosporidium parvum Oocysts in Sediment and Biosolids by Immunomagnetic Separation
Authors: Molloy Stephanie L. , Montgomery Annabel E. , Huffman Debra E. , Rose Joan B.
Published: October 2006

A method for the detection of Cryptosporidium parvum oocysts in sediment and wastewater biosolids has been developed using immunomagnetic separation kits that were designed for use with water. This method requires no pretreatment of the sediment or biosolids samples before the commercial kit application. Oocyst recovery efficiencies from sediment and biosolids using the modified Dynal (Lake Success, New York) and Crypto‐Scan commercial methods (Immucell Corporation, Portland, Maine) ranged from 20 to 60%. While the sensitivity of the method is dependent on the amount of sediment processed and the equivalent volume examined under the microscope, it was able to detect 0.48 oocysts per gram dry weight sediment. Using this method, Cryptosporidium parvum oocysts were found at levels as high as 97 oocysts/g of primary biosolids and at levels up to 4 oocysts/g in polluted sediment.
Recurrence of Fecal Coliforms and Salmonella Species in Biosolids Following Thermophilic Anaerobic Digestion
Authors: Iranpour Reza , Cox Huub H. J.
Published: October 2006

The U.S. Environmental Protection Agency (U.S. EPA) Part 503 Biosolids Rule requires the fecal coliform (indicator) or Salmonella species (pathogen) density requirements for Class A biosolids to be met at the last point of plant control (truck‐loading facility and/or farm for land application). The three Southern Californian wastewater treatment plants in this study produced biosolids by thermophilic anaerobic digestion and all met the Class A limits for both fecal coliforms and Salmonella sp. in the digester outflow biosolids. At two plants, however, a recurrence of fecal coliforms was observed in postdigestion biosolids, which caused exceedance of the Class A limit for fecal coliforms at the truck‐loading facility and farm for land application. Comparison of observations at the three plants and further laboratory tests indicated that the recurrence of fecal coliforms can possibly be related to the following combination of factors: (1) incomplete destruction of fecal coliforms during thermophilic anaerobic digestion, (2) contamination of Class A biosolids with fecal coliforms from external sources during postdigestion, (3) a large drop of the postdigestion biosolids temperature to below the maximum for fecal coliform growth, (4) an unknown effect of biosolids dewatering in centrifuges. At Hyperion Treatment Plant (City of Los Angeles, California), fecal coliform recurrence could be prevented by the following: (1) complete conversion to thermophilic operation to exclude contamination by mesophilically digested biosolids and (2) insulation and electrical heat‐tracing of postdigestion train for maintaining a high biosolids temperature in postdigestion.
Toxicity and biodegradation of chlorophenols in anaerobic propionate enrichment culture
Authors: Jin Peikang , Bhattacharya Sanjoy K.
Published: October 2006

The fate of four trichlorophenols (TCP), six dichlorophenols (DCP), and three monochlorophenols (CP), were studied in anaerobic propionate enrichment systems. TCPs were more toxic than DCPs and CPs; 2,4,5‐TCP was most toxic to the propionate users among the 13 chlorophenols studied in this research. Most chlorophenols were dechlorinated reductively to less chlorinated compounds and/or phenol. Dechlorination at the ortho position was observed most frequently. The overall removal of the selected chlorophenols by anaerobic propionate enrichment systems were in the following order: 2,3,5‐TCP > 2,3,6‐TCP > 3,5‐DCP > 2,4‐DCP > 2‐CP > 3,4‐DCP; 2,3‐DCP; 2,5‐DCP > 3‐CP > 2,4,5‐TCP > 2,6‐DCP > 2,4,6‐TCP > 4‐CP.
A model of alternative ways to meet dissolved oxygen standards
Authors: Houck Carl P. , Thornton Richard J. , Brooks Joan , Saunders J.F.
Published: October 2006

Existing in‐stream dissolved oxygen (DO) standards in portions the South Platte River below Denver are not being met. In the summer, the river is effluent dominated and in‐stream oxidation (nitrification of ammonia) is a significant cause of DO depletion. Facilities were installed to remove ammonia from a portion of treatment plant effluent; while improving water quality, these facilities did not solve the low DO problem. A sophisticated water quality model was used to investigate alternatives to traditional in‐plant treatment. Extensive water quality, fisheries, and aquatic habitat data also were assembled, and a site‐specific DO standard was proposed that protects aquatic life. Modeling indicated that, even if essentially complete ammonia removal were achieved, the DO problem would not be solved. Various combinations of stream reaeration, channel modifications, effluent diversion, and other techniques were examined with the model, and the six preferred alternatives were subjected to model evaluation for each of 4 summer months to meet both acute and chronic DO criteria. Capital and operation and maintenance costs were estimated, and a subjective risk and benefit evaluation was performed. Modeling and refinement of alternatives finally resulted in a recommended alternative involving installation of both passive and active in‐stream reaeration structures that could potentially save $25 to 65 million in capital costs, with substantial savings in annual operating costs as well.
Repair of wastewater microorganisms after ultraviolet disinfection under seminatural conditions
Authors: Baron Jérôme
Published: October 2006

Repair of wastewater microorganisms after ultraviolet (UV) disinfection was studied by incubating secondary effluent previously irradiated to UV doses of 40 to 60 mW·s/cm2 in diffusion chambers for 2 to 24 hours. For somatic coliphage repair estimations, the effluent was incubated in flasks for 2 hours. There was only slight repair of fecal streptococci, and it did not depend on the UV irradiation dose. Repair of the thermotolerant coliforms was a function of the UV dose. Repair corresponded to a maximum increase of 1 log unit after irradiation to 40 mW·s/cm2, and to smaller increases after 50 or 60 mW·s/cm2. No relationship was observed between repair and suspended solids content of the effluent in the range of 4 to 12 mg/L. For the Salmonella, no repair was observed after a 60‐mW·s/cm2 irradiation and a 24‐hour incubation. No repair was observed for the viruses in nine in‐flask incubations, with coliforms showing increases between 1 and 2 log units in the same flasks. Compared with the coliforms, this absence of repair of microorganisms that cause the greatest health risk in bathing and shellfish‐breeding zones brings interesting perspectives in the debate of post‐UV‐irradiation repair.
Secondary clarifier analysis using data from the Clarifier Research Technical Committee protocol
Authors: Vitasovic Zdenkô Cello , Zhou Siping , McCorquodale John A. , Lingren Kong
Published: October 2006

Data obtained through the application of the Clarifier Research Technical Committee (CRTC) protocol were used to perform simulations using a mechanistic dynamic model of the secondary clarifier. The model is verified against field data, and the simulation results are used to analyze clarifier behavior. The information from the CRTC protocol provides a foundation for model‐based analysis. Limitations of clarifier analysis based solely on empirical observation are discussed.
Retardation of volatile organic compound movement by a soil‐bentonite slurry cutoff wall amended with ground tires
Authors: Park Jae K. , Kim Jae Y. , Madsen Curtis D. , Edil Tuncer B.
Published: October 2006

Laboratory‐scale column tests were conducted to investigate the retardation of volatile organic compound (VOC) movement through a soil–bentonite (SB) slurry cutoff wall material amended with ground tires, which was found to sorb a significant amount of VOCs. The hydraulic conductivity of the SB slurry cutoff wall backfill material was not affected by the addition of ground tires. The hydraulic conductivity of the ground‐tire‐amended SB backfill specimen increased 1.1 to 1.2 times after the spiking with VOCs; however, that of the conventional SB backfill specimen increased 1.7 to 1.8 times. The effective porosity of the backfill specimens tested was in the range of 70 to 100%. The partition coefficient of trichloroethylene (TCE) increased from 0.96 to 13.41 L/kg when 15% by weight of ground tires was added. As a result, the time for TCE to break through to 10% of the influent concentration became approximately 10 times longer by the addition of 15% ground tires by weight. Ground tire addition to the SB slurry cutoff wall appears to provide a significant amount of VOC retardation capacity without deteriorating the performance of the slurry cutoff wall.
Preparation of basic yttrium carbonate for phosphate removal
Authors: Haran M.J. , Wasay S.A. , Tokunaga S.
Published: October 2006

Removal of phosphate ions from aqueous solutions has been studied with basic yttrium carbonate (BYC) of different compositions prepared by homogeneous precipitation with yttrium chloride and urea. Higher carbonate content was obtained with higher concentration of urea. Removal of phosphate was significant at pH less than 12 and dependent on the composition of BYC. The possible mechanism for removal is ion exchange with carbonate or hydroxide groups between pH 7 and 12 and through complex formation of phosphate with yttrium ions and ion exchange between pH 2 and 6. The phosphate adsorption capacity of BYC prepared with a higher concentration of urea was higher than that of BYC prepared with a lower urea concentration. The removal of phosphate followed a Langmuir model. The BYC of higher carbonate content gave higher percentage removal in the pH range of 6 to 11. The high phosphate adsorption capacity of the compound can be attributed to its carbonate group content and surface area. The phosphate adsorption was not affected by F−, SO42−, NO3−, Br−, and I− in the basic pH range.
Trichloroethylene and methane feeding strategies to sustain degradation by methanotrophic enrichments
Authors: Walter Gunter A. , Strand Stuart E. , Herwig Russell P. , Treat Tanya P. , Stensel David H.
Published: October 2006

Metabolite toxicity production during trichloroethylene (TCE) degradation by methanotrophic bacteria can lead to partial or complete inactivation of the TCE‐degrading enrichment. The general objectives of this research were to determine if TCE and methane feeding strategies could be selected that would reduce metabolite toxicity effects and determine operating conditions that would sustain TCE‐degrading methanotrophic enrichments. In batch treatment of TCE with and without methane, the presence of methane doubled the amount of TCE degraded per unit biomass (0.051 mg TCE/mg biomass). In a closed complete‐mix methanotrophic enrichment reactor continuously fed TCE and methane, reactor failure occurred at a loading of only 0.005 mg TCE/mg volatile suspended solids (VSS) · d. In the same type of reactor operation with intermittent TCE feeding and continuous methane feeding, TCE degradation was sustained at daily loadings of 0.03 mg TCE/mg VSS · d. The intermittent TCE‐fed reactor could produce an effluent TCE concentration below the drinking water standard (0.005 mg/L) at a higher TCE loading than the continuous‐fed system (0.03 versus 0.0025 mg TCE/mg VSS · d). The system with intermittent TCE feeding provided more efficient use of methane relative to TCE degradation. The amount of methane consumed per unit of TCE degraded was 33 and 167 mg methane/mg TCE for the intermittent and continuous TCE‐fed operations, respectively. With continuous TCE exposure, the methanotrophic population in the continuous TCE‐fed reactor changed to a type that is characterized by having less soluble TCE‐oxidizing enzymes and slower TCE oxidation rates.