Sang-Il Lee

Prescribed burning is a significant source of fine particulate matter (PM2.5) in the southeastern United States. However, limited data exist on the emission characteristics from this source. Various organic and inorganic compounds both in the gas and particle phase were measured in the emissions of prescribed burnings conducted at two pine-dominated forest areas in Georgia. The measurements of volatile organic compounds (VOCs) and PM2.5 allowed the determination of emission factors for the flami

Much effort has been applied in estimating the concentrations of chlorophyll-a (Chl a) in lakes. The optical complexity and lack of in situ data complicate estimating Chl a in such water bodies. We compared four established satellite reflectance algorithms—the two-band and three-band algorithms (2BDA, 3BDA), fluorescence line height (FLH), and normalized difference chlorophyll index (NDCI)—to estimate Chl a concentration in Lake Chad. We evaluated the performance and applicability of Landsat-8 (

An unanticipated wind shift led to the advection of plumes from two prescribed burning sites that impacted Atlanta, GA, producing a heavy smoke event late in the afternoon on February 28, 2007. Observed PM2.5 concentrations increased to over 140 microg/m3 and O3 concentrations up to 30 ppb in a couple of hours, despite the late hour in February when photochemistry is less vigorous. A detailed investigation of PM2.5 chemical composition and source apportionment analysis showed that the increase i

Most study participants showed more favorable attitudes toward vaginal delivery than cesarean delivery. This result does not support the assumption that the upsurge of cesarean section rates in South Korea is associated with women's positive attitudes toward cesarean section. The main cause of the rapid rise of cesarean section rates in South Korea during the past two decades have its origins in health care practitioners and the health care system in which they work.

Here we demonstrate an unconventional fabrication of highly transparent supercapacitors and electrodes using random networks of nanostructured metallic glass nanotroughs for their integrations as wirelessly rechargeable and invisible, skin heat patches. Transparent supercapacitors with fine conductive patterns were printed using an electrohydrodynamic jet-printing. Also, transparent and stretchable electrodes, for wireless antennas, heaters and interconnects, were formed using random network bas

Consistent observations of lakes and reservoirs that comprise the majority of surface freshwater globally are limited, especially in Africa where water bodies are exposed to unfavorable climatic conditions and human interactions. Publicly available satellite imagery has increased the ability to monitor water bodies of various sizes without much financial hassle. Landsat 7 and 8 images were used in this study to estimate area changes around Lake Chad. The Automated Water Extraction Index (AWEI),

Recent work has shown that the brain's default mode network (DMN) is active when people imagine the future. Here, we test in human participants (both sexes) whether future imagination can be decomposed into two dissociable psychological processes linked to different subcomponents of the DMN. While measuring brain activity with fMRI as subjects imagine future events, we manipulate the vividness of these events to modulate the demands for event construction, and we manipulate the valence of these

We consider digital predistortion (DPD) for linearizing power amplifiers (PAs) of hybrid MIMO systems with subarrays. Designing such a DPD scheme is difficult because one DPD should linearize all PAs of a subarray whose beamforming coefficients are time-varying. We develop an adaptive DPD technique for each subarray based on direct learning method minimizing the sum of squared errors between the input and output signals of PAs. Use of the least mean square (LMS) Newton algorithm is proposed to a

Abstract. Extensive forest fires occurred during late July 2014 across the forested region of Siberia, Russia. Smoke plumes emitted from Siberian forest fires underwent long-range transport over Mongolia and northeast China to the Korean Peninsula, which is located ∼ 3000 km south of the Siberian forest. A notably high aerosol optical depth of ∼ 4 was observed at a wavelength of 500 nm near the source of the Siberian forest fires. Smoke plumes reached 3–5 km in height near the source and fell be

Particulate matter (PM) less than 2.5 microm in size (PM2.5) source apportionment by chemical mass balance receptor modeling was performed to enhance regional characterization of source impacts in the southeastern United States. Secondary particles, such as NH4HSO4, (NH4)2SO4, NH4NO3, and secondary organic carbon (OC) (SOC), formed by atmospheric photochemical reactions, contribute the majority (>50%) of ambient PM2.5 with strong seasonality. Source apportionment results indicate that motor vehi

Vesicular traffic in the Drosophila melanogaster oocyte occurs actively during vitellogenesis. Although endocytosis in the oocyte has been well characterized, exocytic vesicular traffic is less well understood. We show that the oocyte endoplasmic reticulum (ER) becomes concentrated into subcortical clusters during vitellogenesis. This ER reorganization requires Jagunal, which is an evolutionarily conserved ER membrane protein. Loss of Jagunal reduces vesicular traffic to the oocyte lateral membr