Reversals in nature and the nature of reversals

The asymmetric shape of reversals of the Earth's magnetic field indicates a possible connection with relaxation oscillations as they were early discussed by van der Pol. A simple mean-field dynamo model with a spherically symmetric $\alpha$ coefficient is analysed with view on this similarity, and a comparison of the time series and the phase space trajectories with those of paleomagnetic measurements is carried out. For highly supercritical dynamos a very good agreement with the data is achieved. Deviations of numerical reversal sequences from Poisson statistics are analysed and compared with paleomagnetic data. The role of the inner core is discussed in a spectral theoretical context and arguments and numerical evidence is compiled that the growth of the inner core might be important for the long term changes of the reversal rate and the occurrence of superchrons.Comment: 24 pages, 12 figure

Non-alcoholic beverages and risk of bladder cancer in Uruguay

BACKGROUND: Bladder cancer is the fourth most frequent malignancy among Uruguayan men. A previous study from Uruguay suggested a high risk of bladder cancer associated with maté drinking. We conducted an additional case-control study in order to further explore the role of non-alcoholic beverages in bladder carcinogenesis. METHODS: In the time period 1996–2000, 255 incident cases with transitional cell carcinoma of the bladder and 501 patients treated in the same hospitals and in the same time period were frequency matched on age, sex, and residence. Both cases and controls were face-to-face interviewed on occupation, tobacco smoking, alcohol drinking and intake of maté, coffee, tea, and soft drinks. Statistical analysis was carried out by unconditional multiple logistic regression. RESULTS: Ever maté drinking was positively associated with bladder cancer (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.2–3.9) and the risk increased for increasing duration and amount of maté drinking. Both coffee and tea were strongly associated with bladder cancer risk (OR for coffee drinking 1.6, 95% CI 1.2–2.3; OR for tea drinking 2.3, 95% CI 1.5–3.4). These results were confirmed in a separate analysis of never-smokers. CONCLUSION: Our results suggest that drinking of maté, coffee and tea may be risk factors for bladder carcinoma in Uruguay

From point cloud to BIM: a survey of existing approaches

International audienceIn order to handle more efficiently projects of restoration, documentation and maintenance of historical buildings, it is essentialto rely on a 3D enriched model for the building. Today, the concept of Building Information Modelling (BIM) is widely adoptedfor the semantization of digital mockups and few research focused on the value of this concept in the field of cultural heritage.In addition historical buildings are already built, so it is necessary to develop a performing approach, based on a first step ofbuilding survey, to develop a semantically enriched digital model. For these reasons, this paper focuses on this chain startingwith a point cloud and leading to the well-structured final BIM; and proposes an analysis and a survey of existing approacheson the topics of: acquisition, segmentation and BIM creation. It also, presents a critical analysis on the application of this chainin the field of cultural heritag

The use of the laser confocal scanning microscopy to measure resin remnants on customized lingual bracket

Background: The study aimed to evaluate the permanence of resin and enamel remains on lingual brackets at the end of orthodontic treatment and after the debonding procedure. The evaluation of resin remnants on customized lingual brackets bases has never done before in other studies because they are curved, and traditional techniques are not applicable. Methods: The sample consisted of 100 lingual brackets (25 incisors, 25 canines, 25 premolars, 25 molars) scanned with a confocal laser microscope (OLS4000). We measured the brackets' surface and the area of resin remnants with the software of the microscope. Median and quartiles were presented to describe the data. ARI calculation was indirect for each tooth, measuring the resin remnants to the total surface of the bracket. The Kruskal-Wallis test and Fisher test were applied respectively to compare the percentages of remnants and the frequencies of the ARI between the four groups. Results: After the analyses, 13 brackets had no adhesive remnants (ARI 0), 29 brackets had less than 50% of resin remnants (ARI 1), 50 brackets had more than 50% of resin remnants (ARI 2), and 8 brackets had 100% of adhesive (ARI 3). Canines brackets presented the lower amount of resin followed by premolars, incisors, and molars. Conclusion: Lingual brackets showed a high frequency of ARI = 2. The median percentage of the bracket surface covered by resin was 41%. We observed a slight tendency of more resin remnants on molar brackets, due to half-pad configuration. The authors suggest paying attention during the debonding procedure of molar brackets since a stronger connection between the adhesive and the bracket mesh means a higher risk of enamel damage

structural reliability of rc elements with electric arc furnace slag as recycled aggregates

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Eucalyptus oil to mitigate heat stress in broilers.

ABSTRACT The objective of this study was to evaluate performance, hematological parameters, leukocyte counts, and respiratory microbiota of broilers under heat stress receiving eucalyptus oil supplementation. Cobb broilers (n = 1200) were randomly distributed on the first day of life in a factorial arrangement with additional treatment (2 × 2 + 1) with two periods of oil administration via drinking water (daily, from 18 to 35 days of life) and two periods of oil administration via spray (daily, from 18 to 35 days of age) plus a control treatment, consisting of twelve replications, with 20 animals each. The birds were kept in a controlled environment with constant temperature at 32 °C to induce heat stress by infrared heaters. Eucalyptus oil was supplied by drinking water (1 L of oil to 4000 L of water) or by spray applications with a pump (1 L of oil to 200 L of water). Bird weight was recorded at 42 days of age, along with remaining feed, to determine weight gain, feed intake, and feed conversion. In addition, one blood sample from each bird repetition was collected for hematological and leucocytic evaluation. To assess respiratory microbiota, a tracheal flushing was performed for bacteria counts. There was no difference in performance, hematological parameters, and leukocyte counts, except hematocrit, which was lower in birds that received eucalyptus oil after 18 days of age. No significant differences were observed in the respiratory microbiota comparing oil-treated and -untreated groups. Although it was not possible to verify statistical difference, the birds that received eucalyptus oil via spray plus spray from 18 days old showed lower bacterial counts and absence of isolation of Gram negatives, while the control group was the one with the highest number of Gram negatives. Therefore, eucalyptus oil can be used for heat-stressed broilers without impairing their development