The Academy of Dental Materials: Providing roots and wings.

ObjectivesThe long history of the Academy of Dental Materials (ADM) is documented with its strategies (a) to rapidly communicate science among its members, (b) to establish special awards to stimulate new science, and (c) to develop new dental materials scientists.MethodsWe searched the history of the last 35 years of the ADM newsletters, transactions, journals, and officer notes. We document the (a) presidents, (b) meeting history, (c) membership growth, and (d) development of special awards through 2019 with the recent creation of the ADM Marshall Post-Doctoral Award.ResultsThere are 36 years of recent ADM history, 42 international meetings, membership growth to 400 individuals from 15 countries, service of 19 presidents, Paffenbarger annual Awardees since 1989, induction of >200 fellows, and recognition of the first winner of Marshall Post-Doctoral Award in 2018. New directions for recruiting members are suggested. Three potential new thrusts for the organization are presented: artificial intelligence, genetic engineering, and intensive member mentoring.SignificanceThese suggestions for the ADM provide a path for the ADM to continue to adapt to the ever changing scientific landscape

Power for tests of interaction: effect of raising the Type I error rate

Abstract Background Power for assessing interactions during data analysis is often poor in epidemiologic studies. This is because epidemiologic studies are frequently powered primarily to assess main effects only. In light of this, some investigators raise the Type I error rate, thereby increasing power, when testing interactions. However, this is a poor analysis strategy if the study is chronically under-powered (e.g. in a small study) or already adequately powered (e.g. in a very large study). To demonstrate this point, this study quantified the gain in power for testing interactions when the Type I error rate is raised, for a variety of study sizes and types of interaction. Methods Power was computed for the Wald test for interaction, the likelihood ratio test for interaction, and the Breslow-Day test for heterogeneity of the odds ratio. Ten types of interaction, ranging from sub-additive through to super-multiplicative, were investigated in the simple scenario of two binary risk factors. Case-control studies of various sizes were investigated (75 cases & 150 controls, 300 cases & 600 controls, and 1200 cases & 2400 controls). Results The strategy of raising the Type I error rate from 5% to 20% resulted in a useful power gain (a gain of at least 10%, resulting in power of at least 70%) in only 7 of the 27 interaction type/study size scenarios studied (26%). In the other 20 scenarios, power was either already adequate (n = 8; 30%), or else so low that it was still weak (below 70%) even after raising the Type I error rate to 20% (n = 12; 44%). Conclusion Relaxing the Type I error rate did not usefully improve the power for tests of interaction in many of the scenarios studied. In many studies, the small power gains obtained by raising the Type I error will be more than offset by the disadvantage of increased "false positives". I recommend investigators should not routinely raise the Type I error rate when assessing tests of interaction

Interrogation of fibre Bragg gratings through a fibre optic rotary joint on a geotechnical centrifuge

The monitoring of an array of fibre Bragg gratings (FBGs) strain sensors was performed through a single channel, single mode fibre optic rotary joint (FORJ) mounted on a geotechnical centrifuge. The array of three FBGs was attached to an aluminum plate that was anchored at the ends and placed on the model platform of the centrifuge. Acceleration forces of up to 50g were applied and the reflection signal of the monitored FBGs recorded dynamically using a 2.5kHz FBG interrogator placed outside the centrifuge. The use of a FORJ allowed the monitoring of the FBGs without submitting the FBG interrogator to the high g-forces experienced in the centrifuge. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

ENVIRONMENTAL POLICY INFLUENCES ON LIVESTOCK STOCKING AND LOCATION DECISIONS

This paper explores the relationship between state level environmental regulations and stocking and location decisions in the U.S livestock and poultry industry (beef, chicken, dairy and hogs). Rather than conduct this analysis on a species-by-species basis, we choose to focus upon the overall size of the livestock industry (expressed in animal units) and the size of industry found on large, medium and small operations by state (48) and over time (28 yrs). Results indicate that industry may drive policy rather than the converse. However, since we also find that existing policy rules have differential impacts on the industry by operation size, we conclude that structural change in the industry may be driven in part by size or legal structure discriminating regulations.Demand and Price Analysis, Livestock Production/Industries,

Association between fire-safe cigarette legislation and residential fire deaths in the United States

Abstract: Background: Cigarettes and other tobacco-related smoking products have traditionally been a major ignition source for residential fire deaths. In the United States, all 50 states and the District of Columbia have passed laws requiring that cigarettes self-extinguish if they are not being smoked (so-called fire-safe cigarette laws). The purpose of this study was to quantify the association between state-level implementation of fire-safe cigarette legislation and the rate of residential fire death. Methods: Poisson regression was used to analyze state-years data. Main intervention: Implementation dates for fire-safe cigarette legislation in each state. Outcome: Residential fire mortality rate. Results: Implementation of fire-safe cigarette legislation was associated with a 19% reduction in overall residential fire mortality rates, adjusted for demographic differences between states (rate ratio = 0.81, 95% confidence interval: 0.79, 0.84). This is approximately similar to the estimated proportion of residential fire deaths in which smoking materials are an ignition source (23%). Legislation implementation was associated with a protective effect for every age, sex, race, and ethnicity strata that we examined. State-specific residential fire mortality death rates decreased (defined as a drop of at least 5%) in 32 states after fire-safe cigarette legislation was implemented. In 12 states there was either less than a 5% decrease or an increase, and seven states had insufficient deaths to evaluate state-level changes. Conclusions: Implementation of fire-safe cigarette is associated with reductions in residential fire mortality rates

Restorative Dental Materials: Scanning Electron Microscopy and X-Ray Microanalysis

Restorative dental materials include the materials used to repair damaged teeth and/or replace missing teeth. The definition could be extended to include a much broader group of dental materials, but this paper concentrates only on those materials used to restore the crown portion of damaged teeth. Auxiliary materials, materials for removable denture prostheses, and root canal materials are excluded. Progress and recent research utilizing SEM (Scanning Electron Microscopy), EDS (Energy Dispersive Spectroscopy), and some related methods are presented for the following dental materials: dental amalgam, enamel and dentin bonding agents, dental composites, dental cements, casting alloys for crowns and bridges, and ceramic-metal and ceramic restorative materials. In addition to the basic characterization of these materials by SEM/EDS techniques, examples of replication methods for SEM study of restorative materials in situ are discussed. Some examples are also presented in the direct use of SEM/EDS for characterization of changes and degradation of restorative materials which occur during clinical use

VARIABLE GROWTH IMPACTS ON OPTIMAL MARKET TIMING IN ALL-OUT PRODUCTION SYSTEMS

This paper addresses the economic impacts of growth variability on market timing decisions in an all-in, all-out production system. Marketing decisions based on the pen average are determined to be different than those based on the entire distribution of output levels. A case study data set of 350 swine provides verification of our theoretical construct.Production Economics,

Early head injury and attention deficit hyperactivity disorder: retrospective cohort study

Objective To explore the hypothesis that medically attended head injury in young children may be causal in the later development of attention deficit hyperactivity disorder

Exploration of the effects of classroom humidity levels on teachers’ respiratory symptoms

Previous studies indicate that teachers have higher asthma prevalence than other non-industrial worker groups. Schools frequently have trouble maintaining indoor relative humidity (RH) within the optimum range (30-50%) for reducing allergens and irritants. However, the potential relationship between classroom humidity and teachers’ health has not been explored. Thus, we examined the relationship between classroom humidity levels and respiratory symptoms among North Carolina teachers

Predicting Recovery Patterns After Sport-Related Concussion

Clinicians sometimes treat concussed individuals who have amnesia, loss of consciousness (LOC), a concussion history, or certain symptom types more conservatively, but it is unclear whether recovery patterns differ in individuals with these characteristics