bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effectiveness of Pit and Fissure Sealants
Authors: Weintraub Jane A.
Published: April 2007

This review addresses two major issues related to the use of pit and fissure sealants. First, the epidemiology of occlusal caries for children and adults is examined to determine if there is a basis for administering sealant programs to different age groups. Second, the effectiveness of pit and fissure sealants in fluoridated and non‐fluoridated communities is compared. Changes in effectiveness of sealant over time are evaluated in terms of percent effectiveness, complete retention, caries incidence, and reapplication rates. Based on epidemiologic evidence, sealant programs can be justified for children and young adults, but not for older age groups. Based on the literature reviewed, following one application of autopolymerized or visible‐light‐cured sealant, the median percent effectiveness declines from 83 percent after one year to 55 percent after seven years. Similarly, the median complete retention declines from 92 percent after one year to 66 percent after seven years. Conversely, the median percent of sealed first molars becoming carious and/or restored increases from 4 percent after one year to 31 percent after seven years. Large differences in sealant effectiveness are not apparent between studies performed in fluoridated and fluoride‐deficient communities.
Anticipating the Future and Change
Authors: Blazer Dan G.
Published: April 2007

As in all of medicine, there are basic assumptions underlying the present system of dental education and delivery. These basic assumptions are facing challenges due in part to the marked reduction in the incidence of caries and the development of more effective therapies. This current period of time is described as an era of true change, rather than the mere modification of existing technology. Changes are going to occur in a number of areas. The move will be from government to private, from small to large, from generalist to specialist. Since change is inevitable, one can learn about and prepare for the stress of change, the changes happening now, and how to adapt to change. Although many changes are beyond the individual's control, their occurrence may be beneficial.
Dental Hygienists' Knowledge and Opinions about Fluorides and Fluoridation.
Authors: Chovanec Gale K. , Majerus Georgia J. , Duffy M. Bridget , Bernet Julia K. , Frazier P. Jean , Newell Kathleen J.
Published: April 2007

This article reports results of a study of 563 practicing Minnesota and Wisconsin dental hygienists' knowledge and opinions about fluorides and water fluoridation. Two independent samples were selected randomly from the populations of licensed dental hygienists residing in the two states. Data were collected using a pretested, 42‐item, mailed questionnaire. An 84 percent response was achieved with two followup reminders. These data provide baseline information about the caries prevention knowledge and attitudes of practicing dental hygienists in two states. Respondents from both states held similar levels of knowledge about fluorides and opinions about decision making on fluoridation. Fluoride topics, especially water fluoridation, were not receiving high priority in patient education, although nearly all believed that dental hygienists should promote water fluoridation actively. Two‐thirds of respondents from both states believed fluoridation decisions should be made by health authorities, rather than by elected officials or through public vote. Greater attention to patient education about fluorides and community water fluoridation is needed by dental hygienists.
Factors Influencing Variation in Dentist Service Rates.
Authors: Grembowski David , Milgrom Peter , Flset Louis
Published: April 2007

In the previous article, we calculated dentist service rates for 200 general dentists based on a homogeneous, well‐educated, upper‐middle‐class population of patients. Wide variations in the rates were detected. In this analysis, factors influencing variation in the rates were identified. Variation in rates for categories of dental services was explained by practice characteristics, patient exposure to fluoridated water supplies, and non‐price competition in the dental market. Rates were greatest in large, busy practices in markets with high fees. Older practices consistently had lower rates across services. As a whole, these variables explained between 5 and 30 percent of the variation in the rates.
Patterns of Sealant Delivery Under Variable Third Party Requirements
Authors: Corbin Stephen B. , Clark Norman L. , McClendon B. Jerald , Snodgrass Nancy K.
Published: April 2007

Despite evidence indicating dental sealants to be effective in pre venting caries on the pit and fissure surfaces of teeth, only 8 percent of school‐aged US children had received sealants as of 1986–87. While many rationales have been suggested and scientifically answered for this low level of utilization, issues of cost and cost effectiveness remain considerable barriers to many insurers and public programs. This study reports dentist behavior when sealants were added with few restrictions as a new benefit to an existing third party system of care. Results are compared to another third party program with stricter reimbursement policies. Overall, sealants were provided in a reasonable fashion to both groups of patients, relative to teeth selected for sealing and costs. Only a small proportion of patients receiving sealants were underage sixoraboveage 19. Even under the most liberal program, sealants were predominantly targeted to teeth at highest risk to decay. Still, for both groups, a significant proportion of the sealants were placed in teeth at points in time quite distant from expected eruption patterns and, thus, their periods of highest risk to decay. Overall, dentists appeared to use sealants only minimally in their practices. These data suggest that sealants can be added to third party dental programs with little overall risk of inappropriate use or abuse. They also suggest that specific efforts are merited to educate providers as to the most effective times at which to provide sealants for preventing the maximum amount of decay in a population.
A Fluoridation Campaign: the Phoenix Experience
Authors: Smith Kathleen G. , Christen Karen A.
Published: April 2007

On January 31, 1989, the city council of Phoenix, Arizona, voted to approve water fluoridation. Despite a small number of campaign participants and a limited budget, profluoridationists launched a successful 16‐month effort that included novel marketing techniques, intensive collaboration with media representatives, and an aggressive challenge of the antifluoridation movement. Public support was garnered through an advisory petition effort and positive media coverage; political support resulted from a carefully orchestrated educational strategy that included expert testimony and comprehensive reference materials. With a population of approximately 1 million people, Phoenix is the ninth largest city in the country and, until the measure was implemented, the third largest nonfluoridated city.
The Prevalence of Recurrent Herpes Labialis during an Army Hot Weather Exercise
Authors: Shulman Jay D. , Carpenter William M. , Lewis David L.
Published: April 2007

A survey was performed on 1,062 of 2,500 (42%) Army personnel participating in a desert training exercise at Fort Irwin, California, in September 1983. The prevalence of recurrent herpes labialis (RHL) and chapped lips was observed during the third week of a four‐week training period. Complexion, sex, lip protectant use, age, and time spent outdoors were obtained by observation and interview. Recurrent herpes labialis was found in 46 subjects (4%). Stratified analysis and stepwise logistic regression were used to identify risk factors associated with RHL and to determine the prevalence odds ratios (POR). Risk factors with statistically significant associations with RHL were lip protectant use (POR=0.19), chapped lips (POR=2.87), being female (POR=5.00), and light complexion (POR=2.48). These findings strongly support the use of lip protectants during prolonged exposure to hot, dry climates as a prophylaxis against recurrent herpes labialis. Additional studies should focus on excitatory factors of RHL; and clinical trials of the efficacy of the lip protectants to protect against RHL and chapped lips should be undertaken.
Factors Affecting the Ingestion of Fluoride Dentifrice by Children
Authors: Naccache Hermine , Simard Paul L. , Trahan Luc , Brodeur Jean‐Marc , Demers Marie , Lachapelle Diane , Bernard Paul‐Marie
Published: April 2007

Several factors affecting the amount of fluoride ingested during toothbrushing by 2‐ to 7‐year‐old children were investigated. The specific purpose of this study was to determine the contribution of age, the amount of dentifrice used, and rinsing after brushing to the variation in the ingestion of fluoride dentifrice. Four hundred and five children brushed their teeth in front of a portable sink. The tubes of dentifrice in gel (0.24% NaF) were weighed before and after use to determine the amount of toothpaste used. The fluoride content of the collected liquids was determined with a fluoride‐ion‐specific electrode. The amount of fluoride ingested was derived by determining the difference between the amounts used and recovered. The amount of dentifrice used, the age, and the rinsing habits, entered in a multiple regression model, explained up to 66 percent of the total variation in the amount of fluoride ingested. The amount of dentifrice used accounted by itself for 60 percent of the total variation. Therefore, these results indicate that the quantity of dentifrice used was the most important factor affecting the ingestion of fluoride through toothbrushing by young children.
Opinions of Dentists on the Treatment of Elderly Patients in Long‐term Care Facilities
Authors: MacEntee Michael I. , Weiss Rachel T. , Waxier‐Morrison Nancy E. , Morrison Brenda J.
Published: April 2007

The high prevalence of disorders in the mouths of elderly residents in long‐term care (LTC) facilities suggests that the dental services available to the residents are inadequate. A questionnaire was sent to most of the dentists practicing in Vancouver (British Columbia) to solicit their opinions on treating older patients in LTC facilities, and a response was obtained from 334 (55%). It indicated that 19 percent of the respondents had treated old people within this context, although few of them felt they had been educated adequately for the service. Many reasons were offered to explain the small participation. Most respondents had never been asked to attend a facility. Many felt that it interfered with their practice and leisure, and they were concerned about the limited options available for treatment. Dentists who had attended facilities were motivated by a sense of professional or public responsibility, but they were uneasy about the limited options and about the inadequate space and equipment available. In general, the dentists were not interested in attending an institutionalized geriatric population, and they felt ill‐prepared for the service
Assessing Dental Practice Quality by Evaluating Radiology Items
Authors: Hunt Ronald J. , Fann Shen Jang , Kantor Mel L. , Morris Alvin L.
Published: April 2007

The DEMCAD dental office assessment instrument was developed to evaluate practice quality using Donebedian's quality assessment model of structure, process, and outcome. This previously validated instrument takes about six hours to complete. Subsequent analysis was undertaken to determine whether an abbreviated office assessment based on the evaluation of radiology items was sufficiently sensitive, specific, and practical to be used as a screening instrument for identifying dental offices with very low evaluation scores. Data for this analysis were obtained from 300 volunteer general dental practices evaluated in the field testing of the DEMCAD instrument. The nine radiology structure items predicted very poorly the overall structure scores. How‐ever, 13 radiology process items predicted overall process scores quite accurately. Four of the 13 radiology process items (periodontal diagnoses recorded, interdental bone shown on x‐rays, caries diagnoses recorded, and current x‐rays mounted) produced a combined R2 of. 58. These four radiology variables predicted the 10 percent of the dental practices with the lowest overall process score with 87 percent sensitivity and 93 percent specificity. This analysis showed that an abbreviated dental practice process quality assessment using oral radiology items in an audit of patients' records may be feasible as a screening test for dental office assessment.
Smokeless Tobacco Habits and Oral Mucosal Lesions in Dental Patients
Authors: Little Sally Jo , Stevens Victor J. , LaChance Pierre A. , Severson Herbert H. , Bartley Murray H. , PhD Edward Lichtenstein , Leben Joseph R.
Published: April 2007

As part of a smokeless tobacco (ST) intervention study, we collected data on tobacco use habits and oral health for 245 male ST users aged 15 to 77. The study sample was identified during routine dental office visits and represents a relatively diverse population of patients. Oral health data collection included grading the clinical appearance of oral mucosal lesions using Greer and Poulson's classification system, as well as identifying and recording the primary anatomic location of ST placement. Results show that 78.6 percent of ST users had observable oral lesions, 23.6 percent of which were in the most clinically advanced category (degree III). Of the lesions noted, 85 percent were in the same location the patient identified as his primary area of smokeless tobacco placement. In a comparison sample of 223 non‐ST‐users with the same age distribution, only 6.3 percent had observable lesions. A multiple logistic regression model for ST users showed that lesion presence and severity were most significantly related to current frequency of ST use.
The Development and Practice of Social Dentistry in Germany
Authors: Nippert R. Peter
Published: April 2007

The traditions of social dentistry in Germany represent early forms of dental public health development. It was promoted in dental care facilities where salaried dentists delivered services to target groups, i.e., schoolchildren and sickness fund members. They enabled larger numbers of patients to receive dental care, especially those of lower class origin who otherwise would have remained untreated because of lack of financial resources or scar‐city of manpower. School dental clinics not only delivered dental treatment, but also distributed oral hygiene and nutritional information to school‐aged children. Social dentistry in the prefluoride era in Germany pursued an egalitarian and social‐class oriented concept of dental care delivery, aiming at compensating the detrimental effects that the private practice‐based, fee‐for‐service financed dental care system had produced in the lower classes of the population. The impact of the Nazi regime nearly abolished the institutions of social dentistry. They never were restored in West Germany after World War II. In East Germany dental care had been organized according to traditions of social dentistry, i.e., delivering services in dental treatment centers. Since the unification of the two German states, the institutions of dental care delivery in former East Germany have been restructured to fit the private practice‐based model of former West Germany, eliminating most of the social dentistry institutions in the country.
Dentists, Drugs, and Decisions: Introduction to Part I‐Therapeutic Drugs
Authors: Kula Katherine
Published: April 2007

Numerous dental therapeutic agents or drugs are available over the counter or with prescription for patient use at home or in a professional office. Knowledge of the processes by which these agents are evaluated for safety and efficacy by the FDA and ADA is necessary for dental professionals to make intelligent decisions concerning their use. Several examples of problems with drug/cosmetic evaluations are cited.
FDA's New Drug Evaluation Process: a General Overview
Authors: Walters Philip G.
Published: April 2007

A general overview of the FDA new‐drug evaluation process is presented with special emphasis on the regulatory requirements as outlined in the federal Food, Drug, and Cosmetic Act and the interpretive New Drug Regulations. Included is a description of the administrative/scientific makeup and functions of the new‐drug evaluation divisions within the Center for Drug Evaluation and Research. Some specifics relating to the investigative development of anticaries and plaque/gingivitis new drug products are discussed.
ADA Dental Product Evaluation: Case History
Authors: Barnett Michsael L.
Published: April 2007

The ADA Acceptance Programs entail a rigorous evaluation of products and offer clear benefits to manufacturers, dental professionals, and consumers alike. This paper outlines the implications of the ADA product‐evaluation programs for each of these three constituencies and concludes that while there may be an occasional downside from the manufacturer's standpoint, their net effect is to provide assurances that products are safe, efficacious, and promoted properly.
How the FDA and the ADA Affect Development of Prescription Drugs for Oral Care
Authors: Cooley William E.
Published: April 2007

The patient‐consumer, the health professional, and the producer are all essential in the world of prescription drugs for oral care. Also essential are the Food and Drug Administration (FDA) and the American Dental Association (ADA). The FDA is charged with reviewing new‐drug applications in the United States and approving those drugs that are proved safe and effective. The FDA also controls prescription‐drug advertising and promotion. The ADA applies professional standards in judging all submitted dental drugs. Those drugs accepted by ADA's Council on Dental Therapeutics may display the ADA seal in labeling and advertising. All advertising for accepted products must be cleared by the ADA. An example of a prescription drug approved by the FDA and accepted by the ADA is 0.12 percent chlorhexidine gluconate oral rinse (Peridex). This drug followed the FDA's investigational‐drug (IND) regulations before final approval as a treatment for gingivitis.
Statistical vs Clinical Significance in Product Testing: Can They Be Designed to Satisfy Equivalence?
Authors: Kingman Albert
Published: April 2007

Statistical issues associated with demonstrating significance between treatment groups (efficacy or superiority) and nonsignificance (equivalence) are presented and discussed. Methodologies for demonstrating efficacy of a product are proposed and contrasted, incorporating clinical and statistical criteria, with emphasis on situations in which placebo groups are precluded from the study design. Distinctions are drawn between study designs for demonstrating superiority and those for equivalence, including the determination of sample sizes needed for the different approaches. The “at least as good as” criterion is proposed as a reasonable alternative to that of equivalence in active control equivalence studies for demonstrating that dental product modifications or new products are efficacious.
Dentists' Uncertainties about Materials and Devices: an Introduction to the Problem
Authors: Rule James T.
Published: April 2007

Questions concerning evaluation of dental materials and devices by the FDA and ADA are raised. Examples of several products are discussed.
The How and Why of the ADA's Evaluation of Dental Materials, Instruments, and Equipment
Authors: Fan P. L.
Published: April 2007

The evaluation program of the Council on Dental Materials, Instruments, and Equipment of the American Dental Association is described.
Effect of Regulatory and Professional Guidelines on the Development and Marketing of a Dental Device: Case History
Authors: Ross Candy B.
Published: April 2007

The FDA encourages organizations such as the ADA to develop voluntary standards for drugs and dental devices. The landmark process of gaining ADA approval of an oral irrigator as the first therapeutic device is described. The process was time consuming and expensive, and obligates the manufacturer to submit all future marketing and advertising claims for ADA review. The ADA should continue to ensure standardized guidelines for all product categories. Education of the dental profession and the consumer concerning the significance of the ADA seal of approval is encouraged.
Ethical Perspectives on the FDA and ADA Evaluation of Dental Products
Authors: Veatch Robert M.
Published: April 2007

Contemporary bioethics is concerned with qualitative decisions rather than quantitative decisions. Several examples are discussed including the role of patients as decision makers in their treatment and in their assignment within clinical trial groups.
FDA and ADA Evaluation of Dental Products—Implications for Dentists and their Patients: a View from the Practitioner
Authors: Ousborne Albert L.
Published: April 2007

A general practitioner discusses the problems clinicians encounter in trying to evaluate dental materials and devices. Numerous examples are given. The FDA and ADA should provide more information to dentists concerning their role in monitoring dental products.
The View and Responsibility of the Advertising Agency Toward Advertising Claims
Authors: Sweeney Thomas M.
Published: April 2007

Health care advertising agencies must create communication that is simultaneously creative, scientifically accurate, relevant, within fair balance, simple, motivating, within approved labeling, and approvable by the client, the dental profession, and regulatory bodies. The advertising must also stimulate sales of the product being advertised. Subjective decisions concerning these requirements place the agency and its client at risk for financial losses and embarrassment.
Legal Implications of Using Drugs and Devices in the Dental Office
Authors: Wakeen Linda M.
Published: April 2007

Choosing dental products that are FDA and/or ADA approved is a wise choice concerning their safety and efficacy for approved uses. However, the dentist must show that the product was indicated by a particular patient's needs. Uses of approved dental products in nonapproved ways or use of nonapproved products may be considered as negligence in some malpractice actions, but allowed under standards of reasonableness in other situations. The dentist must be able to justify decisions on a scientific basis. Legal ramifications of various decisions made in the context of difficult prescription choices are discussed.
Human rights and the national interest: migrants, healthcare and social justice
Authors: Cole Phillip
Published: April 2007

The UK government has recently taken steps to exclude certain groups of migrants from free treatment under the National Health Service, most controversially from treatment for HIV. Whether this discrimination can have any coherent ethical basis is questioned in this paper. The exclusion of migrants of any status from any welfare system cannot be ethically justified because the distinction between citizens and migrants cannot be an ethical one.
A qualitative study of institutional review board members’ experience reviewing research proposals using emergency exception from informed consent
Authors: McClure Katie B , Delorio Nicole M , Schmidt Terri A , Chiodo Gary , Gorman Paul
Published: April 2007

Background:Emergency exception to informed consent regulation was introduced to provide a venue to perform research on subjects in emergency situations before obtaining informed consent. For a study to proceed, institutional review boards (IRBs) need to determine if the regulations have been met.

Aim:To determine IRB members’ experience reviewing research protocols using emergency exception to informed consent.

Methods:This qualitative research used semistructured telephone interviews of 10 selected IRB members from around the US in the fall of 2003. IRB members were chosen as little is known about their views of exception to consent, and part of their mandate is the protection of human subjects in research. Interview questions focused on the length of review process, ethical and legal considerations, training provided to IRB members on the regulations, and experience using community consultation and notification. Content analysis was performed on the transcripts of interviews. To ensure validity, data analysis was performed by individuals with varying backgrounds: three emergency physicians, an IRB member and a layperson.

Results:Respondents noted that: (1) emergency exception to informed consent studies require lengthy review; (2) community consultation and notification regulations are vague and hard to implement; (3) current regulations, if applied correctly, protect human subjects; (4) legal counsel is an important aspect of reviewing exception to informed-consent protocols; and (5) IRB members have had little or no formal training in these regulations, but are able to access materials needed to review such protocols.

Conclusions:This preliminary study suggests that IRB members find emergency exception to informed consent studies take longer to review than other protocols, and that community consultation and community notification are the most difficult aspect of the regulations with which to comply but that they adequately protect human subjects.
Theory and practice of informed consent in the Czech Republic
Authors: Krizova Eva , Simek Jiri
Published: April 2007

The large-scale change of Czech society since 1989 has involved the democratic transformation of the health system. To empower the patient was one important goal of the healthcare reform launched immediately after the Velvet Revolution. The process has been enhanced by the accession of the Czech Republic to the European Union and the adoption of important European conventions regulating the area. The concept of informed consent and a culture of negotiation are being inserted into a traditionally paternalistic culture. Our article describes the current situation on the issue of the communication of information on state of health and treatment, and on the question of the participation of the patient in decisions on treatment. We present empirical results of a public opinion survey on this issue. The results show a still prevailing submissive attitude towards the physicians, despite the fact that the concept of informed consent has become more and more publicly familiar (42% of respondents gave the completely correct answer regarding informed consent). The impact of age, education and sex on answers to the questionnaire was analysed. Men, younger and more educated respondents were more likely to show the autonomous attitude, whereas women, older and less educated people tended to show the traditional submissive attitude. Further, our article raises the question of the cultural and historical background within which the current ethically and legally binding norms (products of western democracies, in fact) are interpreted. The question is how far cultural modifications are tolerable in the practical implementation of universal ethical constructs (informed consent).
Characteristics of deaths occurring in hospitalised children: changing trends
Authors: Ramnarayan Padmanabhan , Craig Finella , Petros Andy , Pierce Christine
Published: April 2007

Background:Despite a gradual shift in the focus of medical care among terminally ill patients to a palliative model, studies suggest that many children with life-limiting chronic illnesses continue to die in hospital after prolonged periods of inpatient admission and mechanical ventilation.

Objectives:To (1) examine the characteristics and location of death among hospitalised children, (2) investigate yearwise trends in these characteristics and (3) test the hypothesis that professional ethical guidance from the UK Royal College of Paediatrics and Child Health (1997) would lead to significant changes in the characteristics of death among hospitalised children.

Methods:Routine administrative data from one large tertiary-level UK children’s hospital was examined over a 7-year period (1997–2004) for children aged 0–18 years. Demographic details, location of deaths, source of admission (within hospital vs external), length of stay and final diagnoses (International Classification of Diseases-10 codes) were studied. Statistical significance was tested by the Kruskal–Wallis analysis of ranks and median test (non-parametric variables), χ2test (proportions) and Cochran–Armitage test (linear trends).

Results:Of the 1127 deaths occurring in hospital over the 7-year period, the majority (57.7%) were among infants. The main diagnoses at death included congenital malformations (22.2%), perinatal diseases (18.1%), cardiovascular disorders (14.9%) and neoplasms (12.4%). Most deaths occurred in an intensive care unit (ICU) environment (85.7%), with a significant increase over the years (80.1% in 1997 to 90.6% in 2004). There was a clear increase in the proportion of admissions from in-hospital among the ICU cohort (14.8% in 1998 to 24.8% in 2004). Infants with congenital malformations and perinatal conditions were more likely to die in an ICU (OR 2.42, 95% CI 1.65 to 3.55), and older children with malignancy outside the ICU (OR 6.5, 95% CI 4.4 to 9.6). Children stayed for a median of 13 days (interquartile range 4.0–23.25 days) on a hospital ward before being admitted to an ICU where they died.

Conclusions:A greater proportion of hospitalised children are dying in an ICU environment. Our experience indicates that professional ethical guidance by itself may be inadequate in reversing the trends observed in this study.
Distribution of late instar Lymantria dispar cadavers killed by Entomophaga maimaiga on trunks of several tree species in southwestern Japan
Authors: Jikumaru Shota , Sano Toshikazu
Published: April 2007

Attachment of late-instar Lymantria dispar L. (Lepidoptera: Lymantriidae) cadavers killed by Entomophaga maimaiga Humber, Shimazu et Soper (Zygomycetes: Entomophthorales) on trunks of five dominant tree species was determined in a broadleaf forest in southwestern Japan. The highest numbers of cadavers were found attached to the trunk of Pasania glabra (Thunb.) Oerst., while there were moderate numbers of cadavers on the trunks of Quercus glauca Thunb. and Quercus serrata Thunb. and no cadavers were found attached to trunks of Ilex pedunculosa Miq. and Clethra barbinervis Sieb. et Zucc.. All examined cadavers contained E. maimaiga resting spores. The differences in cadaver attachment among tree species may influence density of E. maimaiga resting spores around tree bases, which act as reservoirs for fungal survival during unfavorable periods or over numerous years. Our results provide important information as to where to collect E. maimaiga resting spores for biological control of L. dispar, especially in forests containing many tree species.
The cooler side of mycorrhizas: their occurrence and functioning at low temperatures
Authors: Tibbett Mark , Cairney John W.G.
Published: April 2007

Mycorrhizal associations occur in a range of habitats in which soils are subject to low temperature (≤15 °C) for a significant part of the year. Despite this, most of our understanding of mycorrhizal fungi and their interactions with their plant hosts is based on physiological investigations conducted in the range 20–37 °C using fungi of temperate origin. Comparatively little consideration has been given to the cold edaphic conditions in which many mycorrhizas survive and prosper, and the physiological and ecological consequences of their low temperature environments. In this review, we consider the distribution and persistence of arbuscular and ectomycorrhizal mycorrhizal associations in cold environments and highlight progress in understanding adaptations to freezing resistance and nutrient acquisition at low temperature in mycorrhizal fungi.
Light- and electron-microscopic observations of Cladosporium sp. growing on basidia of Exobasidum camelliae var. gracilis
Authors: Mims C.W. , Hanlin R.T. , Richardson E.A.
Published: April 2007

Basidia of the plant-pathogenic fungus Exobasidium camelliae var. gracilis Shirai became exposed on the abaxial side of an infected leaf of Camellia sasanqua Thunb. following the sloughing of the undersurface of the leaf. Basidia were formed in tremendous numbers in a distinct hymenium that appeared as a white, felt-like layer. Subsequently, colonies of another fungus, Cladosporium sp. appeared, initially as tiny dark dots on this white layer, but quickly increased in size to form larger circular colonies that were olive-brown to dark brown in color. Adjacent colonies sometimes merged to form larger growths with irregular margins that often covered much of the hymenium on the underside of an E. camelliae-infected leaf. The hyphae that made up a young Cladosporium sp. colony were primarily confined to the surface of the E. camelliae hymenium, and we found no evidence that hyphae actually penetrated living basidia. However, E. camelliae basidia overrun by Cladosporium sp. eventually showed signs of necrosis and finally collapsed and died, creating a slightly sunken area in the hymenium. Hyphae of Cladosporium sp. grew throughout the remains of the dead basidia, but did not appear to spread into the leaf tissue above the pseudoparenchymatous layer of hyphae that gave rise to the basidia. Based upon our observations, it is clear that Cladosporium sp. is a necrotrophic mycoparasite. More specifically, it qualifies as a contact necrotrophic, since it kills basidia without first penetrating them with its hyphae.
Geology of the western margin of the Grand Forks complex, southern British Columbia: high-grade Cretaceous metamorphism followed by early Tertiary extension on the Granby fault
Authors: Laberge J D , Pattison D RM
Published: April 2007

The Grand Forks complex, in the southern Omineca belt of British Columbia, is a fault-bounded tectonic window exposing Proterozoic sediments and associated mafic rocks metamorphosed to upper amphibolite to granulite facies. Its western margin is marked by the Granby fault, an Eocene west-dipping, low-angle, normal fault characterized by brittle deformation. The metasediments of the Grand Forks complex consist of migmatitic paragneiss containing a peak metamorphic assemblage of garnet + cordierite + sillimanite + K-feldspar ± biotite + quartz. Pressure–temperature conditions for this assemblage are 800 ± 35 °C and 5.8 ± 0.6 kbar (1 kbar = 100 MPa). Resorption of garnet to cordierite ± spinel suggests nearly isothermal decompression of about 2 kbar from peak conditions, interpreted to have occurred prior to normal displacement on the Granby fault. Laser ablation U–Pb dating of monazite from the metasediments suggests a dominant episode of Late Cretaceous metamorphism at 84 ± 3 Ma, with evidence for earlier episodes of Cretaceous metamorphism at 119 ± 3 and 104 ± 3 Ma. Early Tertiary recrystallization at 51 ± 2 Ma is coeval with the emplacement of the nearby Coryell plutonic suite. In the hanging wall of the Granby fault, allochthonous sedimentary and volcanic rocks of Quesnel terrane contain mineral assemblages indicative of the upper greenschist to lower amphibolite facies. Pressure–temperature conditions are estimated at 425 ± 40 °C and 2.3 ± 0.7 kbar. The throw (vertical displacement) on the Eocene Granby fault is estimated to be on the order of 5 km. While significant, the fault cannot account for the entire amount of tectonic uplift of the core complex.
Benchmarking airport reconstruction projects
Authors: Hantziagelis Sandra , McCabe Brenda
Published: April 2007

The impact of redevelopment and expansion of airport operations has not received much attention in the literature. Data were collected for 22 North American airports, 26 airport projects, and 107 individual operational years (airport years) with at least 3.5 million passengers annually. Each airport undertook at least one brownfield passenger terminal project between 1991 and 2001. The study shows that some factors, such as traffic volume, air traffic movements, and cargo, may indicate impacts of airport redevelopment. It was also found that the strategic use of space is critical to operational efficiency, especially with the full range of non-aeronautical services that can be offered at airports. The cost of space may be higher, but it tended to improve overall efficiency. Reconstruction projects that were evaluated as successful tended to show operational recovery within 2 years of construction completion; this result was consistent through a wide range of project sizes, traffic levels, and services.Key words: airport terminal reconstruction, benchmarking, reconstruction impacts, airport performance measures, data envelopment analysis.
Investigation of bond between fibre-reinforced polymer bars and concrete under sustained loads
Authors: Shahidi F , Wegner L D , Sparling B F
Published: April 2007

Although the use of fibre-reinforced polymer (FRP) bars to replace steel in reinforced concrete is becoming more common, uncertainty remains concerning the long-term performance of FRP, including the effect of a sustained load on the bond between the FRP bars and the concrete. An experimental study was therefore undertaken to investigate the long-term durability of the bond for various types of bars embedded in concrete: one type of glass FRP, two types of carbon FRP, and conventional steel reinforcing bars. Pullout specimens were tested both statically to failure and under sustained loads for periods of up to 1 year while free-end slip was monitored. Results revealed lower short-term bond strengths for FRP bars relative to steel and significant variability in long-term bond-slip performance among FRP bars of different types. Post-testing investigations revealed damage to bar surfaces at the macroscopic level, as well as broken longitudinal fibres and damage to the surface coatings at the microscopic level.Key words: reinforced concrete, fibre-reinforced polymer (FRP), bond, creep, pullout, sustained loads.
Evaluation of sediment control pond performance at construction sites in the Greater Toronto Area
Authors: Gharabaghi B , Fata A , Seters T Van , Rudra R P , MacMillan G , Smith D , Li J Y , Bradford A , Tesa G
Published: April 2007

Receiving water quality concerns associated with increased construction activities in recent years in the Greater Toronto Area has prompted the Toronto and Region Conservation Authority (TRCA) to evaluate design criteria for sediment control ponds employed during the construction period. Stormwater management ponds located in the towns of Richmond Hill and Markham were monitored to obtain stormwater runoff quantity and influent-effluent quality data during site development. The ponds were designed and constructed in accordance with the Ontario Ministry of the Environment Stormwater management planning and design manual 2003 for an enhanced level of protection (i.e., 80% total suspended solids removal). A hydrodynamic and sediment-transport model was used to examine the effect of pond geometry on sediment removal efficiency under varying storm events. The monitoring data and the modelling results clearly demonstrate the importance of proper pond size and geometry design. This paper focuses on the effect of the ratio of pond length to pond width in minimizing the short-circuiting effect and improvement of the sediment removal efficiency of stormwater management ponds. The results of this study will be useful in updating the design criteria for stormwater management ponds.Key words: stormwater, management, pond, design, sediment.
A comparison of two regional seismic damage estimation methodologies
Authors: Onur Tuna , Ventura Carlos E , Finn W D. Liam
Published: April 2007

This paper presents a comparison of the two main regional damage estimation methodologies currently in use, namely the modified Mercalli intensity (MMI) based approach and the spectral parameter based approach. In the first methodology, expected damage is related to ground shaking intensity in terms of MMI through damage probability matrices. In the second methodology, the ground motion intensity is described in terms of spectral acceleration (SA), and building response in terms of spectral displacement (SD). Both methodologies were applied to buildings in Vancouver of three different construction types: single-family wood-frame houses, low-rise unreinforced masonry buildings, and high-rise concrete frame structures with concrete shear walls. The two methodologies predict damage that lies in the same general damage categories of light and moderate, which are defined by fairly broad ranges in mean damage factors. The specific mean damage factors predicted by the two methods for a given location are significantly different, however. The significant differences in mean damage factors imply significant differences in damage costs and hence in seismic risk.Key words: earthquake, damage, seismic risk, vulnerability, modified Mercalli intensity (MMI), spectral response, displacement, acceleration.
Punching shear tests of normal- and high-strength concrete flat plates
Authors: Ozden Sevket , Ersoy Ugur , Ozturan Turan
Published: April 2007

Experimental research was conducted to investigate the punching shear performance of flat plates. A large number of slab specimens of normal- and high-strength concrete were tested under concentric and eccentric loads. The effects of flexural reinforcement and the use of steel fiber reinforcement were investigated. Experimental expressions were developed for the computation of residual slab strength. Experimentally observed punching shear capacities were compared with those from the provisions of Canadian Standards Association (CSA) standard CSA-A23.3-04. The results indicate that concrete strength plays an important role in punching capacity and slab rigidity. Slabs with a higher percentage of flexural reinforcement show an increase in punching capacity. The use of steel fibers results in improved strength and stiffness while also enhancing the postpeak deformability and residual strength. The empirical expressions developed provide reasonably good predictions of residual slab capacities. CSA-A23.3-04 expressions result in conservative punching shear capacity predictions for concentrically loaded slabs and provide good agreement with the experimentally observed punching shear capacities for eccentrically loaded slabs.Key words: reinforced concrete, flat plate, punching shear, strength, high-strength concrete, eccentric loading, slab re inforcement ratio, steel fiber reinforced concrete.
Mobile multimodal extensions to collaborative Web-based systems
Authors: Rankin Jeff H , Kondratova Irina
Published: April 2007

The development of leading-edge multimodal (e.g., concurrent text, voice, and video capabilities) mobile applications as a technology that holds promise for the construction industry is described. Because of the complexity of the products, the relatively short execution time frame, and the number of parties involved, the information exchanged throughout an architectural, engineering, and construction (AEC) project is extensive. Efficiently managing this information exchange is a significant impediment to increasing the overall productivity of the industry. The technology focus of this paper extends today's tools by addressing one of the unique characteristics of the industry: the need for mobility of real-time information in an integrated and collaborative environment. Mobile computing devices have the capabilities and characteristics for wide use in real-time communication of project information to project repositories or between project participants. As the industry moves away from the desktop and laptop Web paradigms toward the mobile Web paradigm, the availability of real-time complete information exchange with the project information repository presents new opportunities for decision-making in the AEC industry. To facilitate more widespread use of the solution applications described, extensive usability research in light of the various processes in the AEC industry is needed; a preliminary framework for this purpose is presented.Key words: project information management, collaborative information systems, mobile computing, multimodal functionality.
Prediction of pressure fluctuations on sloping stilling basins
Authors: Güven A , Günal M , Çevik A
Published: April 2007

Various types of hydraulic jump occurring on horizontal and sloping channels have been analyzed experimentally, theoretically, and numerically and the results are available in the literature. In this study, artificial neural network models were developed to simulate the mean pressure fluctuations beneath a hydraulic jump occurring on sloping stilling basins. Multilayers feed a forward neural network with a back-propagation learning algorithm to model the pressure fluctuations beneath such a type of hydraulic jump (B-jump). An explicit formula that predicts the mean pressure fluctuation in terms of the characteristics that contribute most to the hydraulic jump occurring on the sloping basins is presented. The proposed neural network models are compared with linear and nonlinear regression models that were developed using considered physical parameters. The results of the neural network modelling are found to be superior to the regression models and are in good agreement with the experimental results due to relatively small values of error (mean absolute percentage error).Key words: neural networks, pressure fluctuation, hydraulic jump, sloping stilling basin, explicit NN formulation, regression analysis.
Modeling and coordinating building systems in three dimensions: a case study
Authors: Tabesh A Reza , Staub-French Sheryl
Published: April 2007

This paper presents a case study that investigated a building system coordination process used three-dimensional (3-D) models during design and construction of a complex research facility. We modeled and coordinated a variety of building systems in three dimensions, including architectural, structural, mechanical, electrical, and plumbing systems. We documented the 3-D modeling and coordination process, evaluated existing software tools support of this process, documented the resources required to execute this process, and assessed the impact of the 3-D models on the coordination process. We also identified the design and construction knowledge used to create a coordinated and constructible design. We classified this knowledge in a framework instantiated by examples and concepts found in this study. The framework associates the design and construction constraints that govern the modeling and coordination process with the knowledge domain, the domain context, and the specific modeling and coordination task. The main contributions of the paper are the evaluation of the 3-D coordination process and the identification and classification of building system coordination knowledge.Key words: 3-D modeling, mechanical, electrical, and plumbing (MEP) coordination, building systems, knowledge framework, product and process modeling, constructability.