Restorative Dentistry: Dental composite depth of cure with halogen and blue light emitting diode technology

Objectives To test the hypothesis that a blue light emitting diode (LED) light curing unit (LCU) can produce an equal dental composite depth of cure to a halogen LCU adjusted to give an irradiance of 300 mWcm–2 and to characterise the LCU's light outputs. Materials and methods Depth of cure for three popular composites was determined using a penetrometer. The Student's t test was used to analyse the depth of cure results. A power meter and a spectrometer measured the light output. Results The spectral distribution of the LCUs differed strongly. The irradiance for the LED and halogen LCUs were 290 mWcm–2 and 455 mWcm–2, when calculated from the scientific power meter measurements. The LED LCU cured all three dental composites to a significantly greater (P < 0.05) depth than the halogen LCU. Conclusions An LED LCU with an irradiance 64% of a halogen LCU achieved a significantly greater depth of cure. The LCU's spectral distribution of emitted light should be considered in addition to irradiance as a performance indicator. LED LCUs may have a potential for use in dental practice because their performance does not significantly reduce with time as do conventional halogen LCUs

Description and performance of the Langley differential maneuvering simulator

The differential maneuvering simulator for simulating two aircraft or spacecraft operating in a differential mode is described. Tests made to verify that the system could provide the required simulated aircraft motions are given. The mathematical model which converts computed aircraft motions into the required motions of the various projector gimbals is described

Scatter matrix analysis of plane waves in a layered media

The problem was the application of matrix theory to the solution of the reflection and transmission coefficients for a plane wave incident on a layered media. Background material relating to the problem was reviewed. Equations that were used in the solution of the problem were either derived or explained. The derivations for the reflection and transmission coefficients were carried out in order, starting with the simple case of normal incidence on a junction of two infinite media and progressing through the more difficult case of oblique incidence on a layer of finite thickness separating two infinite media. Scatter matrix analysis for electrical networks was reviewed and was applied to the layered media. Possible simplifications of the resulting equations were considered --Abstract, page ii

A PARTIAL EQUILIBRIUM MODEL OF THE LINKAGES BETWEEN ANIMAL WELFARE, TRADE AND THE ENVIRONMENT IN SCOTLAND

This research analyses the impacts of a scientific advance that improves animal welfare, upon the environment and trade in Scotland using partial equilibrium (PE) modelling. The science improves pig neonatal survival through improved (high fibre) sow diets used before mating. Our model simulates the effects of animal welfare changes on the pig production systems (pig meat) and further on trade flows (trade in pig meat) and environment (water and air pollution). We consider two animal welfare simulation scenarios, namely the status quo – no animal welfare change as regards pig neonatal mortality (baseline scenario) and the case of improving pig neonatal survival (alternative scenario) and compare the impacts on trade and environment between the two scenarios during the simulation horizon 2008-2015. The results show that the increase in animal welfare has a lower impact on the environment in the alternative scenario compared to the baseline scenario (by about 6% at the end of the simulation horizon) and a positive impact on net trade in the alternative scenario compared to the baseline scenario (by about 13% at the end of the simulation horizon).Pig Welfare, Trade, Environment, Scotland, Partial Equilibrium Model., Agricultural and Food Policy, Environmental Economics and Policy, Research Methods/ Statistical Methods, Q18, Q50,

Flight test evaluation of an RAF high altitude partial pressure protective assembly

A partial pressure suit was evaluated during tests in an F-104 and F-15 as a protective garment for emergency descents. The garment is an pressure jerkin and modified anti-g suit combined with an oronasal mask. The garment can be donned and doffed at the aircraft to minimize thermal buildup. The oronasal mask was favored by the pilots due to its immobility on the face during high g-loading. The garment was chosen to provide optimum dexterity for the pilot, which is not available in a full pressure suit, while protecting the pilot at altitudes up to 18,288 meters, during a cabin decompression, and subsequent aircraft descent. During cabin decompressions in the F-104 and F-15, cabin pressure altitude was measured at various aircraft angles of attack, Mach numbers, and altitudes to determine the effect of the aerodynamic slipstream on the cabin altitude

Opportunities and barriers for niche marketing of lamb in European LFAs based on consumer attitudes to product quality

With commodity prices continuing to decrease and with policy constraint that farmers cannot easily increase their incomes by increasing volumes of production, they must find alternative ways to maintain their standard of living. This can be achieved by either niche marketing of agricultural products or by environmental payments, which are paid by either the government or the consumer. The results of a consumer survey carried out in Less Favoured Areas in Scotland, Germany, Greece, France and Italy to assess consumer attitudes of what constitutes the quality of lamb and the extent to which this provides an opportunity to exploit niche marketing, are discussed. Consumers generally have much less interest in the use of regional labelling, ecologically friendly production systems or the linkage of landscape and production systems in the buying decision. It is concluded that potential exists to develop niche markets for lamb and that these niches demonstrate significant regional differences. Equally, however, it is concluded that there are only limited rewards for production systems which are sympathetic to the environment. To achieve this goal, policy intervention is required, geared directly to environmental management practices. Future policy support towards farmers in LFAs is needed as a mix of policy instruments. Nowadays, financial support of farming in LFAs is necessary to grant farmers income, but structural support (e. g. in marketing products under reliable labelling towards consumers’ requests with trust in the “added valuesâ€) can help to increase LFA-farmers income without increasing subsidies.Consumer expectations, lamb marketing, EU 2078/92 Agri-Environmental Programme, less favoured areas, local markets, Consumer/Household Economics, Demand and Price Analysis, Marketing,

The Relative Importance of Physical Versus Service Attributes with Respect to Small Business Vendor Selection

Recent literature on the topic of vendor selection has focused on a broad, macro view of the relationship between the selection and buying processes (see e.g., Dempsey, 1978; Holt, 1981). However, most of the studies have not examined such processes in the context of the small business enterprise nor have they discriminated between the importance of physical versus service attributes. A recent study by Manzer, Ireland, and Van Auken (1981) did employ the small business in a matrix approach to vendor selection. However, there appears to be a paucity of research involving the relative importance of physical versus service attributes by small businesses in their vendor selection

Noether Currents of Charged Spherical Black Holes

We calculate the Noether currents and charges for Einstein-Maxwell theory using a version of the Wald approach. In spherical symmetry, the choice of time can be taken as the Kodama vector. For the static case, the resulting combined Einstein-Maxwell charge is just the mass of the black hole. Using either a classically defined entropy or the Iyer-Wald selection rules, the entropy is found to be just a quarter of the area of the trapping horizon. We propose identifying the combined Noether charge as an energy associated with the Kodama time. For the extremal black hole case, we discuss the problem of Wald's rescaling of the surface gravity to define the entropy.Comment: 4 page

The Importance of Physical Versus Service Attributes in the Vendor Selection Process

Recent literature on the topic of vendor selection has focused on a broad, macro view of the relationship between the selection and buying processes. However, most of the studies have not examined such processes in the context of the small business enterprise nor have they discriminated between the importance of physical versus service attributes. There appears to be a paucity of research involving the relative importance of physical versus service attributes by small businesses in their vendor selection. The purpose of this research was to examine the printing needs of small businesses in terms of both physical and service attributes related to the product

A Survey of Horse Training in New England

New England no longer has a significant horse training industry. It has many small operations with no obvious and overlapping training philosophies or practices. Show and competition programs are intense and competitive at regional, national and even international levels leading to the observation that techniques employed are equally strategic and tediously designed in order to encourage the exemplary results in the show ring. This study aimed to examine the methods, routines, and strategies that are used by top tier trainers in the New England region of the United States. This information was collected both in survey form and in interview form, to maximize collection and indications of how each particular trainer, breeder, or owner was most easily contacted. The data was then compiled, analyzed for trends, outliers, and other points of interest with the end goal of giving a basic but thorough view of the methods and strategies used by trainers of prestige in the New England area. Results of this study will hold relevance both to those interested in this luxury hobby and to economy minded individuals, as horses are still a substantial percentage of livestock in the New England area. Future studies in the New England area could target a larger group of trainers and stables, while future studies could also be performed in other regions of the United States