Spectrum measurements of the sun near 1 cm wavelength

The solar brightness temperature was measured at frequencies of 19.0, 21.0, 22.2, 23.5, and 25.5 GHz on 8 days in February and March, 1966. The observed average brightness temperatures were 10 800, 10 900, 11 000, 10 700, and 9 800°K, respectively. The daily values were close to these averages.Presently at the University of Maryland.     

A Sensitive and Versatile Multiplex PCR System for the Rapid Detection of Enterotoxigenic (ETEC), Enterohaemorrhagic (EHEC) and Enteropathogenic (EPEC) Strains of Escherichia coli

Although Escherichia coli is widely distributed in the marine environment, only a small percentage are pathogenic to humans. Nonetheless, the widespread occurrence of waterborne infections of E. coli origin in humans has become one of the major health problems worldwide. To date, several types of enterovirulent E. coli have been recognized as the aetiologic agents of various gastrointestinal infections in humans. The most commonly encountered are those belonging to the enterotoxigenic (ETEC), enteroinvasive (EIEC), enterohaemorrhagic (EHEC) and enteropathogenic (EPEC) subtypes. In order to better determine the health risks that are associated with exposure to some of these specific subtypes, we have developed a very sensitive multiplex PCR system for the rapid detection and typing of ETEC, EHEC and possibly EPEC strains of E. coli in the aquatic environment. The target genes chosen for this investigation included: the PHO-A housekeeping gene (present in all E. coli); the LT1, LT2 and ST1 genes of ETEC; the VT1 and VT2 verotoxin, and EAE virulence genes of EHEC and EPEC, respectively. Six pairs of oligonucleotide primers were designed to simultaneously amplify internal fragments of these genes by multiplex PCR to generate PCR products that could be analysed and confirmed with relative ease by gel electrophoresis and HincII enzyme digestion. The results showed that the six sets of PCR primers were highly specific for their target genes and produced specific amplimers of the expected size from several control strains of E. coli – ATCC 35401 (LT1+/ST1+); SA53 (LT2+/VT2+); and O157 (VT1+/VT2+/EAE+). The detection sensitivity of the multiplex PCR system for the six target genes in an E. coli cell mixture was optimized and enhanced by preincubating serially diluted cells in Luria-Bertani broth for 6 h prior to PCR analysis. The results obtained indicated a detection sensitivity of 10° CFU (of each strain) per 100 μl reaction. Multiplex PCR analysis of seawater samples collected from four sewage-polluted sites in Hong Kong indicated the presence in all four samples of E. coli bacteria that were positive for LT1, ST1, VT1 and EAE virulence genes. Overall, the data indicated that the multiplex PCR system described in this study is a potentially very useful and powerful method for routine monitoring and risk assessment of water quality.     

Effects of rainfall on oil droplet size and the dispersion of spilled oil with application to Douglas Channel,British Columbia,Canada

Raindrops falling on the sea surface produce turbulence. The present study examined the influence of rain-induced turbulence on oil droplet size and dispersion of oil spills in Douglas Channel in British Columbia, Canada using hourly atmospheric data in 2011–2013. We examined three types of oils: a light oil (Cold Lake Diluent - CLD), and two heavy oils (Cold Lake Blend - CLB and Access Western Blend - AWB). We found that the turbulent energy dissipation rate produced by rainfalls is comparable to what is produced by wind-induced wave breaking in our study area. With the use of chemical dispersants, our results indicate that a heavy rainfall (rain rate > 20 mm h^? 1) can produce the maximum droplet size of 300 μm for light oil and 1000 μm for heavy oils, and it can disperse the light oil with fraction of 22–45% and the heavy oils of 8–13%, respectively. Heavy rainfalls could be a factor for the fate of oil spills in Douglas Channel, especially for a spill of light oil and the use of chemical dispersants.     

Bayesian probabilistic damage detection of a reinforced‐concrete bridge column

A Bayesian probabilistic approach for damage detection has been proposed for the continuous monitoring of civil structures (Sohn H, Law KH. Bayesian probabilistic approach for structure damage detection. Earthquake Engineering and Structural Dynamics 1997; 26 :1259–1281). This paper describes the application of the Bayesian approach to predict the location of plastic hinge deformation using the experimental data obtained from the vibration tests of a reinforced‐concrete bridge column. The column was statically pushed incrementally with lateral displacements until a plastic hinge is fully formed at the bottom portion of the column. Vibration tests were performed at different damage stages. The proposed damage detection method was able to locate the damaged region using a simplified analytical model and the modal parameters estimated from the vibration tests, although (1) only the first bending and first torsional modes were estimated from the experimental test data, (2) the locations where the accelerations were measured did not coincide with the degrees of freedom of the analytical model, and (3) there existed discrepancies between the undamaged test structure and the analytical model. The Bayesian framework was able to systematically update the damage probabilities when new test data became available. Better diagnosis was obtained by employing multiple data sets than just by using each test data set separately. Copyright © 2000 John Wiley & Sons, Ltd.     

Organohalogen contaminants and trace metals in North-East Atlantic porbeagle shark (Lamna nasus)

The North-East Atlantic porbeagle (Lamna nasus) population has declined dramatically over the last few decades and is currently classified as ‘Critically Endangered’. As long-lived, apex predators, they may be vulnerable to bioaccumulation of contaminants. In this study organohalogen compounds and trace elements were analysed in 12 specimens caught as incidental bycatch in commercial gillnet fisheries in the Celtic Sea in 2011. Levels of organohalogen contaminants were low or undetectable (summed CB and BDE concentrations 0.04–0.85 mg kg⁻¹ wet weight). A notably high Cd concentration (7.2 mg kg⁻¹ wet weight) was observed in one mature male, whereas the range observed in the other samples was much lower (0.04–0.26 mg kg⁻¹ wet weight). Hg and Pb concentrations were detected only in single animals, at 0.34 and 0.08 mg kg⁻¹ wet weight, respectively. These contaminant levels were low in comparison to other published studies for shark species.     

The impact of health financing and CO<Subscript>2</Subscript> emission on health outcomes in Sub-Saharan Africa: A cross-country analysis

The current paper examines the relationship between health financing (public and out-of-pocket health financing), CO₂ emission and health outcomes in 35 Sub-Saharan African countries for the period of 1995–2012. The panel unit root and cointegration tests are conducted as pre-tests, followed by the estimation of the parameters using the FM-OLS and DOLS techniques. The findings of the study show the importance of public health financing as one of the major factors that lead to better health outcomes, whereas the out-of-pocket expenditure is found to be harmful to population health since it leads to increase under-5 mortality rate. Although the results show a negative relationship between CO₂ and health outcomes, still these results remain inclusive. In addition, the findings reveal the importance of socioeconomic factors such as income and education as key determinants of health outcomes.     

The size, mass, and composition of plastic debris in the western North Atlantic Ocean

This study reports the first inventory of physical properties of individual plastic debris in the North Atlantic. We analyzed 748 samples for size, mass, and material composition collected from surface net tows on 11 expeditions from Cape Cod, Massachusetts to the Caribbean Sea between 1991 and 2007. Particles were mostly fragments less than 10 mm in size with nearly all lighter than 0.05 g. Material densities ranged from 0.808 to 1.24 g ml⁻¹, with about half between 0.97 and 1.04 g ml⁻¹, a range not typically found in virgin plastics. Elemental analysis suggests that samples in this density range are consistent with polypropylene and polyethylene whose densities have increased, likely due to biofouling. Pelagic densities varied considerably from that of beach plastic debris, suggesting that plastic particles are modified during their residence at sea. These analyses provide clues in understanding particle fate and potential debris sources, and address ecological implications of pelagic plastic debris.     

Quantitative dam break analysis on a reservoir earth dam

Mathematical simulations on dam break or failure using BOSS DAMBRK hydrodynamic flood routing dam break model were carried out to determine the extent of flooding downstream, flood travel times, flood water velocities and impacts on downstream affected residences, properties and environmental sensitive areas due to floodwaters released by failure of the dam structure. Computer simulations for one of the worse case scenarios on dam failure using BOSS DAMBRK software accounted for dam failure, storage effects, floodplains, over bank flow and flood wave attenuation. The simulated results reviewed a maximum flow velocity of 2.40 m/s with a discharge of approximately 242 mз /s occurred at 1.00 km downstream. The maximum discharge increased from 244 m³/s (flow velocity = 1.74 m/s occurred at 8^th. km) to 263 m³/s (flow velocity = 1.37 m/s occurred at 12^th. km); about a 39% drop in flow velocity over a distance of 4.00 km downstream. If the entire dam gives way instantly, some spots stretching from 0.00 km (at dam site) to approximately 3.40 km downstream of the dam may be categorized as “danger zone”, while downstream hazard and economic loss beyond 3.40 km downstream can be classified as “low” or “minimal” zones.