22 research outputs found
Polarimetric radar observations and interpretation of co-cross-polar correlation coefficients
Includes bibliographical references (page 354).Preliminary analysis of all components of the polarimetric radar covariance matrix for precipitation measured with the NCAR S-band dual-polarization Doppler radar (S-Pol) and the Colorado State University-University of Chicago-Illinois State Water Survey (CSU-CHILL) radars is presented. Radar reflectivity at horizontal polarization Zh, differential reflectivity ZDR, linear depolarization ratio LDR, specific differential phase KDP, crosscorrelation coefficient | ρhv | , and two co-cross-polar correlation coefficients, ρxh and ρxv, have been measured and examined for two rain events: the 14 August 1998 case in Florida and the 8 August 1998 case in Colorado. Examination of the coefficients ρxh and ρxv is the major focus of the study. It is shown that hydrometeors with different types of orientation can be better delineated if the coefficients ρxv and ρxv are used. Rough estimates of the raindrop mean canting angles and the rms width of the canting angle distribution are obtained from the co-cross-polar correlation coefficients in combination with other polarimetric variables. Analysis of the two cases indicates that the raindrop net canting angles averaged over the propagation paths near the ground in typical convective cells do not exceed 2.5°. Nonetheless, the mean canting angles in individual radar resolution volumes in rain can be noticeably higher. Although the net canting angle for individual convective cells can deviate by a few degrees from zero, the average over a long propagation path along several cells is close to zero, likely because canting angles in different cells vary in sign. The rms width of the canting angle distribution in rain is estimated to vary mainly between 5° and 15° with the median value slightly below 10°
Modelling of dynamic interaction between structure and trolley for mega container cranes
Multi-PRI Signal Processing for the Terminal Doppler Weather Radar. Part II: Range–Velocity Ambiguity Mitigation
An Examination of Propagation Effects in Rainfall on Radar Measurements at Microwave Frequencies
Multi-PRI Signal Processing for the Terminal Doppler Weather Radar. Part I: Clutter Filtering
On the Automation of Ports and Logistics Chains in the Adriatic Region
Recently, automation is gaining an even more important role in the port and maritime industry. In particular, several technological innovations are changing both the freight and passenger transport sector. The introduction of these technologies in port terminals (smart ports) require involved stakeholders to adapt their asset and organisations in order to improve the economic competi-tiveness in global markets. The geographical context where new technologies are put in place can also influence their deployment and foreseen impacts. Hence, in order to take the proper decisions at a strategic level and maximize the positive effects in a selected scenario, a feasibility analysis is essential. In the present study, this challenge is addressed for the Adriatic region by proposing a proce-dure for evaluating and selecting the most promising innovations. Several rele-vant stakeholders from the selected area are inquired to assess the relevance and deployment difficulties for a set of new technologies dealing with automation in port areas. Then, the impacts on technical operation and labour market are as-sessed, thus, providing valuable information to support the regional organisations in facing the change and deploying procedures to be potentially replicated in other geographical areas
Small intestinal bacterial overgrowth and nonalcoholic fatty liver disease diagnosed by transient elastography and liver biopsy
Background: We aimed to determine if there was a higher incidence of small intestinal bacterial overgrowth (SIBO) in nonalcoholic fatty liver disease (NAFLD) than in patients without NAFLD. Moreover, we assessed whether patients with significant fibrosis (SF) had a higher incidence of SIBO compared to patients with non-significant or no liver fibrosis.
Methods: NAFLD was diagnosed in 117 patients by using Fibroscan with a controlled attenuation parameter (CAP) as well as liver biopsy (LB). SIBO was defined by esophagogastroduodenoscopy with an aspiration of the descending duodenum.
Results: Patients with nonalcoholic steatohepatitis (NASH) and those with SF on LB had a significantly higher incidence of SIBO than patients without NASH and those without SF, respectively (p<0.05). According to histological characteristics, there was a higher proportion of patients in the SIBO group with higher steatosis and fibrosis grade, lobular and portal inflammation, and ballooning grade (p<0.001). In multivariate analysis, significant predictors associated with SF and NASH were type 2 diabetes mellitus (T2DM) and SIBO. Moreover, in multivariate analysis, significant predictors that were independently associated with SIBO were T2DM, fibrosis stage, and ballooning grade (OR 8.80 (2.07-37.37), 2.50 (1.16-5.37) and 27.6 (6.41-119), respectively). The most commonly isolated were gram-negative bacteria, predominantly Escherichia coli and Klebsiella pneumoniae.
Conclusion: In this relatively large population of patients, we used a gold standard for both SIBO (quantitative culture of duodenum's descending part aspirate) and NAFLD (LB), and we demonstrated that NASH patients and those with SF had a higher incidence of SIBO. Moreover, significant predictors independently associated with SIBO were T2DM, fibrosis stage, and ballooning grade. Although TE is a well-investigated method for steatosis and fibrosis detection, in our study, independent predictors of SIBO were histological characteristics of NAFLD, while elastographic parameters did not reach statistical significance
Science Applications of Phased Array Radars
Abstract
Phased array radars (PARs) are a promising observing technology, at the cusp of being available to the broader meteorological community. PARs offer near-instantaneous sampling of the atmosphere with flexible beam forming, multifunctionality, and low operational and maintenance costs and without mechanical inertia limitations. These PAR features are transformative compared to those offered by our current reflector-based meteorological radars. The integration of PARs into meteorological research has the potential to revolutionize the way we observe the atmosphere. The rate of adoption of PARs in research will depend on many factors, including (i) the need to continue educating the scientific community on the full technical capabilities and trade-offs of PARs through an engaging dialogue with the science and engineering communities and (ii) the need to communicate the breadth of scientific bottlenecks that PARs can overcome in atmospheric measurements and the new research avenues that are now possible using PARs in concert with other measurement systems. The former is the subject of a companion article that focuses on PAR technology while the latter is the objective here.Department of Defense (DoD)Department of Energy (DOE)National Aeronautics and Space Administration (NASA)National Ocean and Atmospheric Administration (NOAA)National Science Foundation (NSF