Factors that influence the quality of final impressions for fixed dental prostheses in Nairobi, Kenya

Background: Good quality dental impressions free of air bubbles, voids, steps, drags, streaks and tears are a pre-requisite for the fabrication of well-fitting fixed dental prostheses (FDP). The quality of impressions is dependent on clinician and material factors. Aim: To evaluate factors that influence the quality of final impressions for FDP in Nairobi, Kenya.  Methods: In this cross-sectional study, 234 impressions received by five dental laboratories were analyzed. The study collected information on the type of tray, impression material, technique, type of prostheses, and clinically detectable errors, including voids, inadequate material at margins, tears, steps, drags, and streaks. Impression quality was the outcome assessed as good, fair, or poor by two investigators. The independent variables influencing impression quality included clinician specialty, experience, impression material, technique, and tray type. Results: Inter-rater agreement was 96.8% (p<0.001). Clinician experience ranged between 1-45yrs, median 13.5yrs and mean 8.39±11.96yrs. The majority were GPs, 80.8% while restorative dentists were 11.5% and other specialists, 7.7%. Most impressions were non-aqueous elastomers, 97.9% employing dual-viscosity technique, 75.6%. Impression trays included stock metal, 60.3%, stock plastic, 34.2%, and custom, 5.5%. Impression quality was good, 24.8%, fair, 37.2% or poor, 38.0%. Cumulatively, 74.5% impressions had bubbles/voids, 53.0% tears and 43.2% poor margins. Clarity of margins was associated with clinician specialty, (Fisher’s exact=9.372, p=0.047), and impression technique with impression quality, (Pearson’s ?2 = 6.385, p=0.041). Compared to restorative specialists, estimated odds of other specialists producing poor margins was 5.71, 95%CI 1.55,21.06, Wald ?2=5.24, p=0.009 while for GPs, the estimated odds was 2.19, 95%CI 0.88, 5.43, Wald ?2 = 2.86, p=0.09. Compared to dual viscosity, estimated odds of monophase giving a poor-quality impression was 1.52, 95%CI 0.83,2.78, Wald ?2 = 1.52, p=0.18. Conclusion: Most impressions were good or fair hence acceptable. Quality of impressions was influenced by clinician specialty and impression technique

Satellite observations for detecting and forecasting sea-ice conditions: A summary of advances made in the SPICES Project by the EU's Horizon 2020 Programme

The detection, monitoring, and forecasting of sea-ice conditions, including their extremes, is very important for ship navigation and offshore activities, and for monitoring of sea-ice processes and trends. We summarize here recent advances in the monitoring of sea-ice conditions and their extremes from satellite data as well as the development of sea-ice seasonal forecasting capabilities. Our results are the outcome of the three-year (2015-2018) SPICES (Space-borne Observations for Detecting and Forecasting Sea-Ice Cover Extremes) project funded by the EU's Horizon 2020 programme. New SPICES sea-ice products include pancake ice thickness and degree of ice ridging based on synthetic aperture radar imagery, Arctic sea-ice volume and export derived from multisensor satellite data, and melt pond fraction and sea-ice concentration using Soil Moisture and Ocean Salinity (SMOS) radiometer data. Forecasts of July sea-ice conditions from initial conditions in May showed substantial improvement in some Arctic regions after adding sea-ice thickness (SIT) data to the model initialization. The SIT initialization also improved seasonal forecasts for years with extremely low summer sea-ice extent. New SPICES sea-ice products have a demonstrable level of maturity, and with a reasonable amount of further work they can be integrated into various operational sea-ice services

Understanding earthquake hazards in southern California - the "LARSE" project - working toward a safer future for Los Angeles

The Los Angeles region is underlain by a network of active faults, including many that are deep and do not break the Earth’s surface. These hidden faults include the previously unknown one responsible for the devastating January 1994 Northridge earthquake, the costliest quake in U.S. history. So that structures can be built or strengthened to withstand the quakes that are certain in the future, the Los Angeles Region Seismic Experiment (LARSE) is locating hidden earthquake hazards beneath the region to help scientists determine where the strongest shaking will occur

Upper Crustal Structure from the Santa Monica Mountains to the Sierra Nevada, Southern California: Tomographic Results from the Los Angeles Regional Seismic Experiment, Phase II (LARSE II)

In 1999, the U.S. Geological Survey and the Southern California Earthquake Center (SCEC) collected refraction and low-fold reflection data along a 150-km-long corridor extending from the Santa Monica Mountains northward to the Sierra Nevada. This profile was part of the second phase of the Los Angeles Region Seismic Experiment (LARSE II). Chief imaging targets included sedimentary basins beneath the San Fernando and Santa Clarita Valleys and the deep structure of major faults along the transect, including causative faults for the 1971 M 6.7 San Fernando and 1994 M 6.7 Northridge earthquakes, the San Gabriel Fault, and the San Andreas Fault. Tomographic modeling of first arrivals using the methods of Hole (1992) and Lutter et al. (1999) produces velocity models that are similar to each other and are well resolved to depths of 5-7.5 km. These models, together with oil-test well data and independent forward modeling of LARSE II refraction data, suggest that regions of relatively low velocity and high velocity gradient in the San Fernando Valley and the northern Santa Clarita Valley (north of the San Gabriel Fault) correspond to Cenozoic sedimentary basin fill and reach maximum depths along the profile of ∼4.3 km and >3 km, respectively. The Antelope Valley, within the western Mojave Desert, is also underlain by low-velocity, high-gradient sedimentary fill to an interpreted maximum depth of ∼2.4 km. Below depths of ∼2 km, velocities of basement rocks in the Santa Monica Mountains and the central Transverse Ranges vary between 5.5 and 6.0 km/sec, but in the Mojave Desert, basement rocks vary in velocity between 5.25 and 6.25 km/sec. The San Andreas Fault separates differing velocity structures of the central Transverse Ranges and Mojave Desert. A weak low-velocity zone is centered approximately on the north-dipping aftershock zone of the 1971 San Fernando earthquake and possibly along the deep projection of the San Gabriel Fault. Modeling of gravity data, using densities inferred from the velocity model, indicates that different velocity-density relationships hold for both sedimentary and basement rocks as one crosses the San Andreas Fault. The LARSE II velocity model can now be used to improve the SCEC Community Velocity Model, which is used to calculate seismic amplitudes for large scenario earthquakes

Estimating Animal Abundance in Ground Beef Batches Assayed with Molecular Markers

Estimating animal abundance in industrial scale batches of ground meat is important for mapping meat products through the manufacturing process and for effectively tracing the finished product during a food safety recall. The processing of ground beef involves a potentially large number of animals from diverse sources in a single product batch, which produces a high heterogeneity in capture probability. In order to estimate animal abundance through DNA profiling of ground beef constituents, two parameter-based statistical models were developed for incidence data. Simulations were applied to evaluate the maximum likelihood estimate (MLE) of a joint likelihood function from multiple surveys, showing superiority in the presence of high capture heterogeneity with small sample sizes, or comparable estimation in the presence of low capture heterogeneity with a large sample size when compared to other existing models. Our model employs the full information on the pattern of the capture-recapture frequencies from multiple samples. We applied the proposed models to estimate animal abundance in six manufacturing beef batches, genotyped using 30 single nucleotide polymorphism (SNP) markers, from a large scale beef grinding facility. Results show that between 411∼1367 animals were present in six manufacturing beef batches. These estimates are informative as a reference for improving recall processes and tracing finished meat products back to source

Food Consumption and its Impact on Cardiovascular Disease: Importance of Solutions Focused on the Globalized Food System A Report From the Workshop Convened by the World Heart Federation

Major scholars in the field, based on a 3-day consensus, created an in-depth review of current knowledge on the role of diet in CVD, the changing global food system and global dietary patterns, and potential policy solutions. Evidence from different countries, age/race/ethnicity/socioeconomic groups suggest the health effects studies of foods, macronutrients, and dietary patterns on CVD appear to be far more consistent though regional knowledge gaps are highlighted. There are large gaps in knowledge about the association of macronutrients to CVD in low- and middle-income countries (LMIC), particularly linked with dietary patterns are reviewed. Our understanding of foods and macronutrients in relationship to CVD is broadly clear; however major gaps exist both in dietary pattern research and ways to change diets and food systems. Based on the current evidence, the traditional Mediterranean-type diet, including plant foods/emphasizing plant protein sources, provides a well-tested healthy dietary pattern to reduce CV

Commercial spruce plantations support a limited. canopy fauna: Evidence from a multi taxa comparison of native and plantation forests

Globally, the total area of plantation forest is increasing as deforestation and fragmentation of native forest continues. In some countries commercial plantations make up more than half of the total forested land. Internationally, there is growing emphasis on forestry policy for plantations to deliver biodiversity and ecosystem services. In Ireland, native forest now comprises just 1% of total land cover while non-native spruce forest makes up 60% of the plantation estate and approximately 6% of the total land cover. The majority of plantation invertebrate biodiversity assessments focus on ground-dwelling species and consequently a good understanding exists for these guilds, especially ground-active spiders and beetles. Using a technique of insecticide fogging, we examine the less well understood component of forest systems, the canopy fauna (Coleoptera, Araneae, Diptera and Hemiptera), in Irish spruce plantations (Sitka and Norway) and compare the assemblage composition, richness and abundance to that of remnant native forest (ash and oak). In addition, we examine the potential for accumulation of forest species in second rotation spruce plantations and identify indicator species for each forest type. From 30 sampled canopies, we recorded 1155 beetles and 1340 spiders from 144 species and over 142 000 Diptera and Hemiptera from 71 families. For all taxa, canopy assemblages of native forests were significantly different from closed-canopy plantation forests. No indicators for plantation forest were identified; those identified for native forest included species from multiple feeding guilds. Plantations supported approximately half the number of beetle species and half the number of Diptera and Hemiptera families recorded in native forests. Although assemblages in Norway spruce plantations were very different to those of native forest, they had consistently higher richness than Sitka spruce plantations. No differences in richness or abundance were found between first rotation and second rotation Sitka spruce plantations. Compared to other forest types, Sitka spruce plantations contained far greater total abundance of invertebrates, due to vast numbers of aphids and midges. Under current management, Sitka spruce plantations provide limited benefit to the canopy fauna typical of native forests in either first or second rotations. The large aphid populations may provide abundant food for insectivores but may also lead to reduced crop production through defoliation. Progressive forestry management should attempt to diversify the plantation canopy fauna, which may also increase productivity and resilience to pest species

The Social Dynamics of Software Development

A variety of experiences in software development processes between a public sector organisation and several software vendors over a decade-long period are described and interpreted. Three information systems histories are presented as case examples and their analysis is based on detailed insider observations. A social process model is used to describe the relationships between key actors within the client organisation while a transaction cost framework is used to explain the joint forms of the relationships between the client and the vendors. The resulting model depicts in a concise way how the relationships have evolved and stabilised over time. In this model, major encounters between the actors are those which have at least the potential to change the relationship state between the parties. The relatively stable passages between consecutive encounters are labelled episodes. By perceiving systems development as a series of encounters and episodes, it is possible to identify the critical turning points of development work and to display the dynamics of a software development trajectory. While our findings support the well-known basic software procurement principle, this is only after the trajectories have stabilised. Two of the three trajectories exhibit major changes in software procurement strategies before reaching a steady state. The paper ends with a discussion of the findings and some implications for researchers and practitioners. © 2000 Elsevier Science Ltd