96 research outputs found

    A STUDY ON THE VARIATIONS OF INNER ORIENTATION PARAMETERS OF A HYPERSPECTRAL FRAME CAMERA

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    New low-cost hyperspectral frame sensors have created a new perspective for remote sensing applications. In this work, we investigate some issues related to the geometric calibration of a hyperspectral frame camera based of FPI (Fabry-Pérot Interferometer), the Rikola camera. The approach proposed in paper is to study the changes in internal optical path caused by the FPI and by the splitting prism. The aim is to model the changes in the IOPs with an analytical function and also to estimate the misalignments between sensors. Several experiments were performed. The changes in position of a specific point were analasyzed to confirm that the bundle of rays is deviated. A self-calibrating bundle adjustment was performed and the Interior Orientation Parameters (IOP) of each band were estimated. The IOPs were analysed and it was concluded that a single set of symmetrical radial distortion parameters can be used for all band. Also, the estimated parameters for each image band were analysed as a function of the air gap of the FPI interferometer. It was noticed some correlation between the focal length and the air gap, and an air-gap dependent model was estimated. Thus, instead of considering an IOP set for each band or for each sensor, a single set of distortion parameters and another set of parameters that is “air-gap dependent”, was assessed. Another important issue was the determination of the misalignment angles between the two sensors, which can explain some differences in the recovered camera trajectory when performing the bundle adjustment

    Adopting a portfolio of ultrasonic and advanced bipolar electrosurgery devices from a single manufacturer compared to currently used ultrasonic and advanced bipolar devices: a probabilistic budget impact analysis from a Spanish hospital perspective

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    Aims: Advanced energy devices are commonly used in electrosurgery, including ultrasonic and advanced bipolar (ABP) devices. Smoke evacuation and reusable dispersive electrodes are also utilized during electrosurgery to improve staff and patient safety. This study assessed the budget impact of adopting a portfolio of Ethicon energy devices compared to devices from other manufacturers from a Spanish hospital perspective. Methods: The main analysis compared the Ethicon advanced energy device portfolio (ultrasonic and ABP devices) to Non-Ethicon advanced energy devices. It was assumed that 4,000 procedures using one advanced energy device each were performed annually, and the cost impact of operating room time, length of stay, and transfusions were considered. A probabilistic budget impact analysis with 10,000 iterations was conducted for generalizability to other hospitals in Spain and Europe. Secondary analysis assessed whether cost savings from the Ethicon advanced energy device portfolio could offset costs of adopting smoke evacuation and reusable dispersive electrodes (Full Ethicon energy portfolio). Results: In the main analysis, the annual budget impact of introducing the Ethicon advanced energy device portfolio was cost saving in 79.8% of probabilistic iterations (mean: -€945,214; 95% credible interval [CrI]: -€3,242,710; €1,285,942) with a mean budget impact per procedure of -€236 (95% CrI: -€811; €321). In the secondary analysis, adding smoke evacuation and reusable dispersive electrodes was still cost saving in 75.3% of iterations compared to Non-Ethicon advanced energy devices (mean: -€778,208; 95% CrI: -€3,075,086; €1,464,728) with a mean budget impact per procedure of -€97 (95% CrI: -€384; €183). Savings resulted from differences in operating room time, length of hospital stay, and volume of disposable electrodes. Conclusions: Adopting Ethicon advanced energy devices demonstrated economic benefits compared to non-Ethicon devices. Introducing the advanced portfolio may improve surgical care quality and the full portfolio was cost saving while improving OR safety for staff and patients

    Body Mass Index, percent body fat, and regional body fat distribution in relation to leptin concentrations in healthy, non-smoking postmenopausal women in a feeding study

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    BACKGROUND: The relationship between BMI and leptin has been studied extensively in the past, but previous reports in postmenopausal women have not been conducted under carefully controlled dietary conditions of weight maintenance using precise measures of body fat distribution. The aim of the present study was to examine the association between serum leptin concentration and adiposity as estimated by BMI and dual energy x-ray absorptiometry (DEXA) measures (percent body fat, central and peripheral fat, and lean mass) in postmenopausal women. METHODS: This study was conducted as a cross-sectional analysis within the control segment of a randomized, crossover trial in which postmenopausal women (n = 51) consumed 0 (control), 15 (one drink), and 30 (two drinks) g alcohol (ethanol)/d for 8 weeks as part of a controlled diet. BMIs were determined and DEXA scans were administered to the women during the 0 g alcohol treatment, and a blood sample was collected at baseline and week 8 of each study period for leptin analysis. RESULTS AND DISCUSSION: In multivariate analysis, women who were overweight (BMI > 25 to ≤ 30 kg/m(2)) had a 2-fold increase, and obese women (BMI > 30 kg/m(2)) had more than a 3-fold increase in serum leptin concentrations compared to normal weight (BMI ≤25 kg/m(2)) women. When the models for the different measures of adiposity were assessed by multiple R(2), models which included percent body fat explained the highest proportion (approximately 80%) of the serum leptin variance. CONCLUSION: Under carefully controlled dietary conditions, we confirm that higher levels of adiposity were associated with higher concentrations of serum leptin. It appears that percent body fat in postmenopausal women may be the best adiposity-related predictor of serum leptin

    Water relations and photosynthesis as criteria for adequate irrigation management in 'Tahiti' lime trees

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    Irrigation scheduling based on soil moisture status is one of the most useful methods because of its practicality and low cost. The effects of available soil water depletion on evapotranspiration (ETc), transpiration (E), leaf water potential at predawn (psiP) and midday (psiM), stomatal conductance (gs) and net CO2 assimilation (A) in lime 'Tahiti' trees (Citrus latifolia) were evaluated to improve irrigation schedule and minimize water use without causing water stress. The trees were spaced 7 <FONT FACE=Symbol>&acute;</FONT> 4 m and drip-irrigated by four drippers with the available soil water content (AWC) depleted by suspension of irrigation (40 days). Leaf water potential was measured on a pressure chamber (psiP and psiM) and leaf gas exchange was measured by infrared gas analyzer (E, gs and A). Evapotranspiration was determined with the aid of weighing lysimeter. Water soil content and potential (psiS) were monitored with TDR probes and tensiometers, respectively, installed at 0.3, 0.6 and 0.9 m depths. Meteorological variables were monitored with an automatic weather station in the experimental area. The threshold AWC level for the onset of ETc decline was 43%, and 60% for gs, A, E and Y P. Also, psiP was more sensitive to AWC than psiM, and is therefore a better tool for irrigation. When AWC was around 60%, values of psiP and psis were -0.62 MPa and -48.8 kPa, respectively
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