873 resultados para National Measurement System for Time and Frequency.


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OBJECTIVES: (1) To evaluate the changes in surface roughness and gloss after simulated toothbrushing of 9 composite materials and 2 ceramic materials in relation to brushing time and load in vitro; (2) to assess the relationship between surface gloss and surface roughness. METHODS: Eight flat specimens of composite materials (microfilled: Adoro, Filtek Supreme, Heliomolar; microhybrid: Four Seasons, Tetric EvoCeram; hybrid: Compoglass F, Targis, Tetric Ceram; macrohybrid: Grandio), two ceramic materials (IPS d.SIGN and IPS Empress polished) were fabricated according to the manufacturer's instructions and optimally polished with up to 4000 grit SiC. The specimens were subjected to a toothbrushing (TB) simulation device (Willytec) with rotating movements, toothpaste slurry and at three different loads (100g/250g/350g). At hourly intervals from 1h to 10h TB, mean surface roughness Ra was measured with an optical sensor and the surface gloss (Gl) with a glossmeter. Statistical analysis was performed for log-transformed Ra data applying two-way ANOVA to evaluate the interaction between load and material and load and brushing time. RESULTS: There was a significant interaction between material and load as well as between load and brushing time (p<0.0001). The microhybrid and hybrid materials demonstrated more surface deterioration with higher loads, whereas with the microfilled resins Heliomolar and Adoro it was vice versa. For ceramic materials, no or little deterioration was observed over time and independent of the load. The ceramic materials and 3 of the composite materials (roughness) showed no further deterioration after 5h of toothbrushing. Mean surface gloss was the parameter which discriminated best between the materials, followed by mean surface roughness Ra. There was a strong correlation between surface gloss and surface roughness for all the materials except the ceramics. The evaluation of the deterioration curves of individual specimens revealed a more or less synchronous course suspecting hinting specific external conditions and not showing the true variability in relation to the tested material. SIGNIFICANCE: The surface roughness and gloss of dental materials changes with brushing time and load and thus results in different material rankings. Apart from Grandio, the hybrid composite resins were more prone to surface changes than microfilled composites. The deterioration potential of a composite material can be quickly assessed by measuring surface gloss. For this purpose, a brushing time of 10h (=72,000 strokes) is needed. In further comparative studies, specimens of different materials should be tested in one series to estimate the true variability.

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Purpose: To describe the evolution of retinal thickness in eyes affected with acute anterior uveitis (AAU) in the course of follow-up and to assess its correlation with severity of inflammatory activity in the anterior chamber. Methods: Design: Prospective, cohort study Setting: Institutional study Patient population: 72 eyes (affected and fellow eyes) of 36 patients Observation procedure: Patients were followed daily until beginning of resolution of inflammatory activity and weekly thereafter. Optical coherence tomography and laser flare photometry were performed at each visit. Treatment consisted of topical corticosteroids Main outcome measures: Retinal thickness of affected eyes, difference in retinal thickness between affected and fellow eyes and their evolution in time, association between maximal retinal thickness and initial laser flare photometry. Results: Difference in retinal thickness between affected and fellow eyes became significant on average seven days from baseline and remained so through-out follow-up (p<0.001). There was a steep increase in retinal thickness of affected eyes followed by a progressive decrease after reaching a peak value. Maximal difference in retinal thickness between affected and fellow eyes was observed between 17 and 25 days from baseline and exhibited a strong, positive correlation with initial laser flare photometry values (p=0.015). Conclusions: Retinal thickness in eyes affected with AAU presents a steep increase over 3 to 4 weeks and then gradually decreases. Severity of inflammation at baseline predicts the amount of retinal thickening in affected eyes. A characteristic pattern of temporal response of retinal anatomy to inflammatory stimuli seems to arise.

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This paper has two main objectives. First, it provides a stylised descriptionof the Catalan industrial path of the period 1830-1861. Second, it reviewsthe evolution of the Catalan industry in the Spanish context and, thus, canserve to describe the relative importance of the Catalan industrialexperience. Consequently, it is mainly devoted to computing and analysing thegrowth rates of Catalan industries during the early phase of industrialisation.The results show that Catalonia experienced a true process ofindustrialisation during the period 1830 to 1861, but that its contributionin rapid increase in Spanish GDP was relatively small.

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The biology of nymphs and adults of the neotropical pentatomid, Dichelops melacanthus (Dallas), feeding on the natural foods, soybean, Glycine max (L.) Merrill immature pods, and corn, Zea mays L. immature seeds, and on an artificial dry diet, was studied in the laboratory. Nymph developmental time was shorter on the natural foods (ca. 21-22 days) than on the artificial diet (28 days), and most nymphs reached adulthood on the food plants (55% on soybean and 73% on corn) than on the artificial diet (40%). Fresh body weight at adult emergence was similar and higher for females raised as nymphs on the natural foods, compared to females from nymphs raised on the artificial diet; for males, weights were similar on all foods. Mean (female and male) survivorship up to day 20, decreased from 55% on soybean to 40% on corn, down to 0% on the artificial diet. Total longevity for females was higher on soybean, while for males was similar on all foods. About three times more females oviposited on soybean than on corn, but fecundity/female was similar on both foods. On the artificial diet, only one out of 30 females oviposited. Fresh body weight of adults increased significantly during the first week of adult life, and at the end of the 3rd week, weight gain was similar on all foods.

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A total of 357 house mice (Mus domesticus) from 83 localities uniformly distributed throughout Switzerland were screened for the presence of a homogenously staining region (HSR) on chromosome 1. Altogether 47 mice from 11 localities were HSR/+ or HSR/HSR. One sample of 11 individuals all had an HSR/HSR karyotype. Almost all mice with the variant were collected from the Rhone valley (HSR frequency: 61%) and Val Bregaglia (HSR frequency: 81%). For samples from most of the area of Switzerland, the HSR was absent. There was no strong association between the geographic distribution of the HSR and the areas of occurrence of metacentrics. However, at Chiggiogna the HSR was found on Rb (1.3). Possible explanations for the HSR polymorphism are discussed.

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Audit report of Iowa Public Employees’ Retirement System as of and for the year ended June 30, 2008

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BACKGROUND/PURPOSE: A new coordinated interdisciplinary unit was created in the acute section of the department of clinical neurosciences, the Acute NeuroRehabilitation (NRA) unit. The objective was to evaluate the impact of the unit and its neurosensory programme on the management of tracheostomy patients in terms of reduction in the average time taken for weaning, weaning success rate and therapeutic efficiency. METHODS: This 49-month retrospective study compares 2 groups of tracheostomy patients before (n = 34) and after (n = 46) NRA intervention. The outcome measures evaluate the benefits of the NRA unit intervention (time to decannulation, weaning and complication rates) and the benefits of the coordination (time to registration in a rehabilitation centre and rate of non-compliance with standards of care). RESULTS: Weaning failure rate was reduced from 27.3% to 9.1%, no complications or recannulations were observed in the post-intervention group after weaning and time to decannulation following admission to our unit decreased from 19.13 to 12.75 days. The rate of non-compliance with patient standards of care was significantly reduced from 45% to 30% (Mann-Whitney p = 0.003). DISCUSSION/CONCLUSIONS: This interdisciplinary weaning programme helped to reduce weaning time and weaning failure, without increased complications, in the sample studied. Coordination improved the efficiency of the interdisciplinary team in the multiplicity and complexity of the different treatments.

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Aim: To describe changes in leisure time and occupational physical activity status in an urban Mediterranean population-based cohort, and to evaluate sociodemographic, health-related and lifestyle correlates of such changes. Methods: Data for this study come from the Cornellè Health Interview Survey Follow-Up Study, a prospective cohort study of a representative sample (n¿=¿2500) of the population. Participants in the analysis reported here include 1246 subjects (567 men and 679 women) who had complete data on physical activity at the 1994 baseline survey and at the 2002 follow-up. We fitted Breslow-Cox regression models to assess the association between correlates of interest and changes in physical activity. Results: Regarding leisure time physical activity, 61.6% of cohort members with ¿sedentary¿ habits in 1994 changed their status to ¿light/moderate¿ physical activity in 2002, and 70% who had ¿light/moderate¿ habits in 1994 did not change their activity level. Regarding occupational physical activity, 74.4% of cohort members who were ¿active¿ did not change their level of activity, and 64.3% of participants with ¿sedentary¿ habits in 1994 changed to ¿active¿ occupational physical activity. No clear correlates of change in physical activity were identified in multivariate analyses. Conclusion: While changes in physical activity are evident in this population-based cohort, no clear determinants of such changes were recognised. Further longitudinal studies including other potential individual and contextual determinants are needed to better understand determinants of changes in physical activity at the population level.

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Abstract Background and aims. Limited data from large cohorts are available on tumor necrosis factor (TNF) antagonists (infliximab, adalimumab, certolizumab pegol) switch over time. We aimed to evaluate the prevalence of switching from one TNF antagonist to another and to identify associated risk factors. Methods. Data from the Swiss Inflammatory Bowel Diseases Cohort Study (SIBDCS) were analyzed. Results. Of 1731 patients included into the SIBDCS (956 with Crohn's disease [CD] and 775 with ulcerative colitis [UC]), 347 CD patients (36.3%) and 129 UC patients (16.6%) were treated with at least one TNF antagonist. A total of 53/347 (15.3%) CD patients (median disease duration 9 years) and 20/129 (15.5%) of UC patients (median disease duration 7 years) needed to switch to a second and/or a third TNF antagonist, respectively. Median treatment duration was longest for the first TNF antagonist used (CD 25 months; UC 14 months), followed by the second (CD 13 months; UC 4 months) and third TNF antagonist (CD 11 months; UC 15 months). Primary nonresponse, loss of response and side effects were the major reasons to stop and/or switch TNF antagonist therapy. A low body mass index, a short diagnostic delay and extraintestinal manifestations at inclusion were identified as risk factors for a switch of the first used TNF antagonist within 24 months of its use in CD patients. Conclusion. Switching of the TNF antagonist over time is a common issue. The median treatment duration with a specific TNF antagonist is diminishing with an increasing number of TNF antagonists being used.

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The critical behavior of a system constituted by molecules with a preferred symmetry axis is studied by means of a Monte Carlo simulation of a simplified two-dimensional model. The system exhibits two phase transitions, associated with the vanishing of the positional order of the center of mass of the molecules and with the orientational order of the symmetry axis. The evolution of the order parameters and the specific heat is also studied. The transition associated with the positional degrees of freedom is found to change from a second-order to a first-order behavior when the two phase transitions are close enough, due to the coupling with the orientational degrees of freedom. This fact is qualitatively compared with similar results found in pure liquid crystals and liquid-crystal mixtures.

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Report on a review of selected general and application controls over the Iowa Public Employees’ Retirement System (IPERS) Legacy and I-Que Pension Administration Systems for the period May 16, 2011 through June 16, 2011

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We consider noncentered vortices and their arrays in a cylindrically trapped Bose-Einstein condensate at zero temperature. We study the kinetic energy and the angular momentum per particle in the Thomas-Fermi regime and their dependence on the distance of the vortices from the center of the trap. Using a perturbative approach with respect to the velocity field of the vortices, we calculate, to first order, the frequency shift of the collective low-lying excitations due to the presence of an off-center vortex or a vortex array, and compare these results with predictions that would be obtained by the application of a simple sum-rule approach, previously found to be very successful for centered vortices. It turns out that the simple sum-rule approach fails for off-centered vortices.