Data on the occurrence and accumulation profiles of butyltins (BTs), including tributyltin (TBT), in marine mammals are scarce. This is the first study to investigate residue levels and accumulation patterns of BTs in cetaceans from Korean coastal waters. The total concentrations of BTs (sum of mono- to tri-butyltins) in minke whales (Balaenoptera acutorostrata) and long-beaked common dolphins (Delphinus capensis) ranged from 15.7 to 297 ng/g wet weight (mean: 100 ng/g wet weight) and from 59.0 to 412 ng/g wet weight (mean: 228 ng/g wet weight), respectively. Dibutyltin (DBT) accounted for 63% of the total BTs in all cetacean samples. Significant species-specific differences in BT concentrations, possibly due to the differences in their habitat and diet, were found between the two cetacean species. The concentrations of DBT and TBT in most cetacean samples exceeded the threshold value for cytotoxic effects in cetaceans, implying potentially adverse health risks from exposure to BTs. 相似文献
Natural oyster shells (NOS) and calcined oyster shells (COS) were used to immobilize arsenic (As) from contaminated mine tailings.
In addition, a blend of Portland cement (PC)/cement kiln dust (CKD) was used as a stabilizing agent. The Korean Standard Test
(KST) method (1 N HCl extraction) was used to evaluate the effectiveness of the treatment. The experimental results showed
that COS effectively immobilized As in treated mine tailings. Specifically, an As concentration less than 1 mg L−1 was obtained following COS treatment at 25 and 30 wt%. However, all the samples subjected to NOS treatments failed the Korean
warning standard of 1.2 mg L−1 after 28 days of curing. All of the COS-PC treatments were successful meeting the Korean warning standard after 7 days of
curing. However, the PC-only treatment failed to meet the Korean warning standard. Similarly, the CKD-only treatment was failed
to meet the Korean warning standard after 7 days of curing. However, the COS-CKD treatment showed that when the COS content
was greater than 20 wt%, less than 1 mg L−1 of As leachability was obtained. Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX) showed needle-like
and torpedo-like Ca–As phases in the COS-treated samples suggesting that As was strongly associated with Ca and O. X-ray absorption
near edge structure (XANES) analyses confirmed that As(V) was prevalent in the tailings and that there were no changes in
As speciation following NOS or COS treatment. 相似文献
Theoretical and Applied Climatology - The studies on poleward expansion of the Hadley circulation have mainly concentrated on linear trends with global warming. There is no consensus on how the... 相似文献
Recently, the estimation of coronal magnetic field using new methods, such as standoff distance method or density compression ratio method has been reported. In the present work, we utilized the density compression ratio of CME-driven shocks for 10 events at 29 different locations in the upper solar corona (10–26R⊙) and determined the coronal magnetic field for two different adiabatic indices (γ=4/3 and 5/3). In addition, radial dependence of shock parameters in the corona is studied. It is found that the magnetic field estimated in the above range agree with the general trend. In addition, we obtained a radial profile of magnetic field [B(R)=623R?1.4] in the entire upper corona (3–30R⊙) by combining the magnetic field estimated by Kim et al. (Astrophys. J. 746:118, 2012) in the range 3–15R⊙ and that estimated in the present study in the range (10–26R⊙). The power-law indices are nearly in agreement with recent results of CME-driven shocks reported in the literature. The results are discussed with the comparison of newly reported coronal magnetic field values obtained by different techniques and found that the power-law relation closely follow the literature values. 相似文献
This paper discusses a near real-time approach to solar active-region monitoring and flare prediction using the Big Bear Solar
Observatory Active Region Monitor (ARM). Every hour, ARM reads, calibrates, and analyses a variety of data including: full-disk
Hα images from the Global Hα Network; EUV, continuum, and magnetogram data from the Solar and Heliospheric Observatory (SOHO);
and full-disk magnetograms from the Global Oscillation Network Group (GONG). For the first time, magnetic gradient maps derived
from GONG longitudinal magnetograms are now available on-line and are found to be a useful diagnostic of flare activity. ARM
also includes a variety of active-region properties from the National Oceanic and Atmospheric Administration's Space Environment
Center, such as up-to-date active-region positions, GOES 5-min X-ray data, and flare-to-region identifications. Furthermore,
we have developed a Flare Prediction System which estimates the probability for each region to produce C-, M-, or X-class
flares based on nearly eight years of NOAA data from cycle 22. This, in addition to BBSO's daily solar activity reports, has
proven a useful resource for activity forecasting.
Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1023/A:1020950221179 相似文献
We present an analysis of all the events (around 400) of coronal shocks for which the shock-associated metric type IIs were
observed by many spectrographs during the period April 1997– December 2000. The main objective of this analysis is to give
evidence for the type IIs related to only flare-blast waves, and thus to find out whether there are any type II-associated
coronal shocks without mass ejections. By carefully analyzing the data from multi-wavelength observations (Radio, GOES X-ray,
Hα, SOHO/LASCO and SOHO/EIT-EUV data), we have identified only 30 events for which there were actually no reports of CMEs.
Then from the analysis of the LASCO and EIT running difference images, we found that there are some shocks (nearly 40%, 12/30)
which might be associated with weak and narrow mass ejections. These weak and narrow ejections were not reported earlier.
For the remaining 60% events (18/30), there are no mass ejections seen in SOHO/LASCO. But all of them are associated with
flares and EIT brightenings. Pre-assuming that these type IIs are related to the flares, and from those flare locations of
these 18 cases, 16 events are found to occur within the central region of the solar disk (longitude ≤45^∘). In this case,
the weak CMEs originating from this region are unlikely to be detected by SOHO/LASCO due to low scattering. The remaining
two events occurred beyond this longitudinal limit for which any mass ejections would have been detected if they were present.
For both these events, though there are weak eruption features (EIT dimming and loop displacement) in the EIT images, no mass
ejection was seen in LASCO for one event, and a CME appeared very late for the other event. While these two cases may imply
that the coronal shocks can be produced without any mass ejections, we cannot deny the strong relationship between type IIs
and CMEs. 相似文献
Summary The linearized equation of motion for the slightly elliptical rotating earth is obtained and using Phinney & Burridge's generalized spherical harmonics, the variational principle is derived for the normal mode oscillations of the Earth. The numerical solutions of two earth models 1066B and B1S6 are searched by minimizing the energy functional for the terrestrial spectral range longer than the lowest order free oscillation. The periods of core modes computed for the earth model B1S6, with stably stratified outer core, ranges from about 4 to 13hr and the periods for the 1066B are much more spread without clustering around the periods of 6 and 12 hr as in B1S6. The results for the earth model 1066B indicate that an outer core can support long-period oscillations even when it is not stably stratified. The Chandler wobble periods obtained are 402.3 day for B1S6 and 402.7 day for 1066B. 相似文献
Hydrogeological responses to earthquakes such as changes in groundwater level, temperature, and chemistry, have been observed for several decades. This study examines behavior associated with ML 5.8 and ML 5.1 earthquakes that occurred on 12 September 2016 near Gyeongju, a city located on the southeast coast of the Korean peninsula. The ML 5.8 event stands as the largest recorded earthquake in South Korea since the advent of modern recording systems. There was considerable damage associated with the earthquakes and many aftershocks. Records from monitoring wells located about 135 km west of the epicenter displayed various patterns of change in both water level and temperature. There were transient-type, step-like-type (up and down), and persistent-type (rise and fall) changes in water levels. The water temperature changes were of transient, shift-change, and tendency-change types. Transient changes in the groundwater level and temperature were particularly well developed in monitoring wells installed along a major boundary fault that bisected the study area. These changes were interpreted as representing an aquifer system deformed by seismic waves. The various patterns in groundwater level and temperature, therefore, suggested that seismic waves impacted the fractured units through the reactivation of fractures, joints, and microcracks, which resulted from a pulse in fluid pressure. This study points to the value of long-term monitoring efforts, which in this case were able to provide detailed information needed to manage the groundwater resources in areas potentially affected by further earthquakes.