2,685 research outputs found
The application of passive sampler (DGT) technology for improved understanding of metal behaviour at a marine disposal site
Metal behaviour and availability at a contaminated dredge material disposal site within UK waters has been investigated using Diffusive Gradient in Thin films (DGT) passive sampling technology. Three stations representing contrasting history and presence of maintenance dredge disposal, including a control station outside the disposal site, have been studied and depth profiles of fluxes of different metals (Fe, Mn, Pb, Cu, Cd, Cr, Ni, Zn) to the binding gel (Chelex 100) have been derived. Higher flux rates and shallower mobilisation of metals (Mn and Fe) to the binding gel were observed at the disposal stations compared to the control station. Here we describe metal mobilization at different depths, linking the remobilization of Fe2+ and Mn2+ to the sediment (re)supply of other heavy metals of interest with a focus on Cd, Ni and Pb and as they are on the Water Framework Directive (WFD) list of priority substances and OSPAR list of priority pollutants. Results showed that Cd, Pb and Ni exhibited signs of resupply at the sediment-water interface (SWI). There was a potential increased mobilisation and source to the water column of Pb and Ni at the disposal site stations, but there was no Cd source, despite higher total loadings. This information has the potential to improve our current understanding of metal cycles at disposal sites. This work can be used as an indication of likely metal bioavailability and also assist in determining whether the sites act as sources or sinks of heavy metals. This information could assist disposal site monitoring and dredge material licensing
Pengaruh Kurs, Inflasi, Libor dan PDB terhadap Foreign Direct Invesment (Fdi) di Indonesia
This study aims to determine the effect of the influence of Exchange Rates, Inflation, Libor, and GDP to the Foreign Direct Invesment (FDI) In Indonesia. The data used in this study is a time series data from 1998 to 2013 were sourced from Invesment Coordinating Board (Badan Koordinasi Penanaman Modal), Bank Indonesia, and Central Bureau of Statistics (Badan Pusat Statisitik). This study used quantitative research methods, and analyzed using multiple linear regression analysis using SPSS 20 application for Windows computers. In this study, the independent variable is Exchange Rates (X1), Inflation (X2), Libor (X3), and GDP (X4), while the dependent is realitation Foreign Direct Invesment (Y).This study tested the hypothesis of regression coefficient (coefficient of determination, a significant test concurrent / F test, and the significant individual test / t test). The result showed that the variable Exchange Rates, Inflation, libor and GDP at once / simultaneously have a significant influence on the realitation Foreign Direct Invesment (FDI). The individual test / partial showed that Gross Domestic Product variable acquired that contributes greater than the variable rate of Exchange Rates, Inflation,and Libor ont the realitation Foreign Direct Invesment (FDI).Keywords:Exchange Rate, Inflation, London Inter Bank Offering Rate (LIBOR), Gross Domestic Product (GDP), and Foreign Direct Invesment (FDI)
The structure of gravel-bed flow with intermediate submergence: a laboratory study
The paper reports an experimental study of the flow structure over an immobile gravel bed in open channel at intermediate submergence, with particular focus on the near-bed region. The experiments consisted of velocity measurements using three-component (stereoscopic) Particle Image Velocimetry (PIV) in near-bed horizontal plane and two-component PIV in three vertical planes that covered three distinctly different hydraulic scenarios where the ratio of flow depth to roughness height (i.e., relative submergence) changes from 7.5 to 10.8. Detailed velocity measurements were supplemented with fine-scale bed elevation data obtained with a laser scanner. The data revealed longitudinal low-momentum and high-momentum "strips'' in the time-averaged velocity field, likely induced by secondary currents. This depth-scale pattern was superimposed with particle-scale patches of flow heterogeneity induced by gravel particle protrusions. A similar picture emerged when considering second-order velocity moments. The interaction between the flow field and gravel-bed protrusions is assessed using cross correlations of velocity components and bed elevations in a horizontal plane just above gravel particle crests. The cross correlations suggest that upward and downward fluid motions are mainly associated with upstream-facing and lee sides of particles, respectively. Results also show that the relative submergence affects the turbulence intensity profiles for vertical velocity over the whole flow depth, while only a weak effect, limited to the near-bed region, is noticed for streamwise velocity component. The approximation of mean velocity profiles with a logarithmic formula reveals that log-profile parameters depend on relative submergence, highlighting inapplicability of a conventional "universal'' logarithmic law for gravel-bed flows with intermediate submergence
Are infestations of Cymomelanodactylus killing Acropora cytherea in the Chagos archipelago?
Associations between branching corals and infaunal crabs are well
known, mostly due to the beneficial effects of Trapezia and Tetralia
crabs in protecting host corals from crown-of-thorns starfish (e.g.,
Pratchett et al. 2000) and/or sedimentation (Stewart et al. 2006).
These crabs are obligate associates of live corals and highly prevalent
across suitable coral hosts, with 1–2 individuals per colony
(Patton 1994). Cymo melanodactylus (Fig. 1) are also prevalent in
branching corals, mostly Acropora, and are known to feed on live
coral tissue, but are generally found in low abundance (<3 per
colony) and do not significantly affect their host corals (e.g., Patton
1994). In the Chagos archipelago, however, infestations of Cymo
melanodactylus were found on recently dead and dying colonies of
Acropora cytherea
Tornado And Severe Weather Climatology And Predictability By Enso Phase In The North Central U.S.: A Compositing Study
Climatological factors, including the phase of the El Niño-Southern Oscillation (ENSO), are known predictors for parameters such as seasonal temperature and precipitation and tropical cyclone activity. ENSO phase also has a relationship to severe weather activity and may have utility in predicting anomalies in severe weather climatology, including the number of significant tornadoes and the number of tornado days. While not useful in daily severe weather operations and forecasting, determining the relationship between ENSO phase and severe weather climatology anomalies can aid preparedness for potentially active seasons among operational meteorologists, emergency managers, the media, and others with a role in preparing spotters and citizens for severe weather seasons
Synoptic-Scale Convective Environment Climatology by ENSO Phase in the North Central United States
The El Niño-Southern Oscillation (ENSO) is known to affect synoptic patterns across the continental United States, particularly by its impact on the upper tropospheric jet stream position. Global circulation patterns influence synoptic weather patterns by impacting the location of mid-tropospheric ridge and trough locations and thus areas favorable for temperature and precipitation anomalies, which in turn influence regional severe weather activity. Though it is one of several factors associated with the potential for severe weather, the synoptic environment plays a key role in severe weather potential by providing favorable ingredients for the development of severe convection (e.g. Miller 1967). While ENSO is one of many factors that influence global circulations, and by distillation may have a less distinguishable influence on the synoptic pattern, coherent signals can be uncovered in the synoptic environment, based on ENSO phase, that would influence the potential for severe convection in the north central United States. Seasonal predictions of severe weather potential are not much aid for daily operations, but they can be used by emergency managers, the media, and forecasters to increase preparedness for seasons that have the potential for above normal convective activity
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