Vulnerability assessment to trihalomethane exposure in water distribution system.

Chlorination is an effective and cheap disinfectant for preventing waterborne diseases-causing microorganisms, but its compounds tend to react with the natural organic matter (NOM), forming potentially harmful and unwanted disinfection by-products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs), and others. The present paper proposes a methodology for estimating the vulnerability with respect to users' exposure to DPBs in water distribution systems (WDSs). The presented application considers total THMs (TTHMs) concentration, but the methodology can be used also for other types of DPBs. Five vulnerability indexes are adopted that furnish different kinds of information about the exposure. The methodology is applied to five case studies, and the results suggest that the introduced indexes identify different critical areas in respect to elevated concentrations of TTHMs. In this way, the use of the proposed methodology allows identifying the higher risk nodes with respect to the different kinds of exposure, whether it is a short period of exposure to high TTHMs values, or chronic exposure to low concentrations. The application of the methodology furnishes useful information for an optimal WDS management, for planning system modifications and district sectorization taking into account water quality

A Pre-screening Procedure for Pollution Source Identification in Sewer Systems

Illicit intrusions in Sewer Systems (SSs), modifying the wastewater characteristics, may create problems to the treatment plant and/or to the final recipient water body. For this reason, the source identification (SI) problem is becoming an important issue also in SSs. For large real systems, the computational burden might make the SI methodologies impractical. In this paper a prescreening procedure, based on the pollution matrix concept, is introduced and applied before the SI methodology. Selecting a group of possible candidate nodes and cutting consequently the scheme, a significant improvement both in terms of time and the accuracy is obtained

Optimal Placement of Water Quality Monitoring Stations in Sewer Systems: An Information Theory Approach

A core problem associated with the water quality monitoring in the sewer system is the optimal placement of a limited number of monitoring sites. A methodology is provided for optimally design water quality monitoring stations in sewer networks. The methodology is based on information theory, formulated as a multi-objective optimization problem and solved using NSGA-II. Computer code is written to estimate two entropy quantities, namely Joint Entropy, a measure of information content, and Total Correlation, a measure of redundancy, which are maximized and minimized, respectively. The test on a real sewer network suggests the effectiveness of the proposed methodology

EVALUATION OF LIVER PARENCHYMA AND PERFUSION USING DYNAMIC CONTRAST-ENHANCED COMPUTED TOMOGRAPHY AND CONTRAST-ENHANCED ULTRASONOGRAPHY IN CAPTIVE GREEN IGUANAS (IGUANA IGUANA) UNDER GENERAL ANESTHESIA

Background: Contrast-enhanced diagnostic imaging techniques are considered useful in veterinary and human medicine to evaluate liver perfusion and focal hepatic lesions. Although hepatic diseases are a common occurrence in reptile medicine, there is no reference to the use of contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) to evaluate the liver in lizards. Therefore, the aim of this study was to evaluate the pattern of change in echogenicity and attenuation of the liver in green iguanas (Iguana iguana) after administration of specific contrast media. Results: An increase in liver echogenicity and density was evident during CEUS and CECT, respectively. In CEUS, the mean \ub1 SD (median; range) peak enhancement was 19.9% \ub1 7.5 (18.3; 11.7-34.6). Time to peak enhancement was 134.0 \ub1 125.1 (68.4; 59.6-364.5) seconds. During CECT, first visualization of the contrast medium was at 3.6 \ub1 0.5 (4; 3-4) seconds in the aorta, 10.7 \ub1 2.2 (10.5; 7-14) seconds in the hepatic arteries, and 15 \ub1 4.5 (14.5; 10-24) seconds in the liver parenchyma. Time to peak was 14.1 \ub1 3.4 (13; 11-21) and 31 \ub1 9.6 (29; 23-45) seconds in the aorta and the liver parenchyma, respectively. Conclusion: CEUS and dynamic CECT are practical means to determine liver hemodynamics in green iguanas. Distribution of contrast medium in iguana differed from mammals. Specific reference ranges of hepatic perfusion for diagnostic evaluation of the liver in iguanas are necessary since the use of mammalian references may lead the clinician to formulate incorrect diagnostic suspicions

Hyperpolarizability and operational magic wavelength in an optical lattice clock

Optical clocks benefit from tight atomic confinement enabling extended interrogation times as well as Doppler- and recoil-free operation. However, these benefits come at the cost of frequency shifts that, if not properly controlled, may degrade clock accuracy. Numerous theoretical studies have predicted optical lattice clock frequency shifts that scale nonlinearly with trap depth. To experimentally observe and constrain these shifts in an $^{171}$Yb optical lattice clock, we construct a lattice enhancement cavity that exaggerates the light shifts. We observe an atomic temperature that is proportional to the optical trap depth, fundamentally altering the scaling of trap-induced light shifts and simplifying their parametrization. We identify an "operational" magic wavelength where frequency shifts are insensitive to changes in trap depth. These measurements and scaling analysis constitute an essential systematic characterization for clock operation at the $10^{-18}$ level and beyond.Comment: 5 + 2 pages, 3 figures, added supplementa

A dedicated protocol and environment for central venous catheter removal in pediatric patients affected by oncohematological diseases

The removal of long-term central venous catheters (CVCs) is not performed according to evidence-based guidelines, thus conveying the message that it is a procedure of secondary importance. Our study aims at comparing the experience at Bambino Gesù Pediatric Hospital before and after the implementation of a dedicated protocol and the identification of a specific area to perform such a procedure under the so-called nonoperating room anesthesia (NORA)