Fetal magnetocardiography using optically pumped magnetometers: a more adaptable and less expensive alternative?

Fetal magnetocardiography provides the requisite precision for diagnostic measurement of electrophysiological events in the fetal heart. Despite its significant benefits, this technique with current cryogenic based sensors has been limited to few centers, due to high cost of maintenance. In this study, we show that a less expensive non-cryogenic alternative, optically pumped magnetometers, can provide similar electrophysiological and quantitative characteristics when subjected to direct comparison with the current technology. Further research can potentially increase its clinical use for fetal magnetocardiography. © 2016 John Wiley & Sons, Ltd.     

The National Vegetation Classification Standard applied to the remote sensing classification of two semiarid environments

The National Vegetation Classification Standard (NVCS) was implemented at two US National Park Service (NPS) sites in Texas, the Padre Island National Seashore (PINS) and the Lake Meredith National Recreation Area (LMNRA), to provide information for NPS oil and gas management plans. Because NVCS landcover classifications did not exist for these two areas prior to this study, we created landcover classes, through intensive ground and aerial reconnaissance, that characterized the general landscape features and at the same time complied with NVCS guidelines. The created landcover classes were useful for the resource management and were conducive to classification with optical remote sensing systems, such as the Landsat Thematic Mapper (TM). In the LMNRA, topographic elevation data were added to the TM data to reduce confusion between cliff, high plains, and forest classes. Classification accuracies (kappa statistics) of 89.9% (0.89) and 88.2% (0.87) in PINS and LMNRA, respectively, verified that the two NPS landholdings were adequately mapped with TM data. Improved sensor systems with higher spectral and spatial resolutions will ultimately refine the broad classes defined in this classification; however, the landcover classifications created in this study have already provided valuable information for the management of both NPS lands. Habitat information provided by the classifications has aided in the placement of inventory and monitoring plots, has assisted oil and gas operators by providing information on sensitive habitats, and has allowed park managers to better use resources when fighting wildland fires and in protecting visitors and the infrastructure of NPS lands.     

Evaluation of aquifer vulnerability and the protective capacity in some oil producing communities of western Niger Delta

Oil spills have become a major environmental hazard constituting serious social problems in Nigeria, especially in the oil producing communities. The spills contaminate the aquifer if the subsurface layers are not protected. Geoelectric technique of geophysical investigation has been used to evaluate the protective capacity of six oil producing communities: Oleh, Olomoro, Uzere, Afiesere, Ekakpamre and Uvwiamuge in the western Niger Delta. A total of 139 vertical electrical sounding (VES) using the Schlumberger electrode configuration were occupied in these communities. The longitudinal conductance maps delineated areas with poor (<0.1 mho), weak (0.1–0.19 mho), moderate (0.2–0.69 mho) and good protective capacity (0.7–4.9 mho). The study has shown that the protective capacity of most parts of the communities studied is poor with Uvwiamuge and Ekakpamre communities not protected hence the aquifer in these oil producing communities are vulnerable to contamination by hydrocarbon in the event of pollution. Hence proper environmental protection measures have been suggested to safeguard the aquifer from pollution by hydrocarbon in the event of spillage.     

Coastal Flood Inundation Monitoring with Satellite C‐band and L‐band Synthetic Aperture Radar Data

Satellite Synthetic Aperture Radar (SAR) was evaluated as a method to operationally monitor the occurrence and distribution of storm‐ and tidal‐related flooding of spatially extensive coastal marshes within the north‐central Gulf of Mexico. Maps representing the occurrence of marsh surface inundation were created from available Advanced Land Observation Satellite (ALOS) Phased Array type L‐Band SAR (PALSAR) (L‐band) (21 scenes with HH polarizations in Wide Beam [100 m]) data and Environmental Satellite (ENVISAT) Advanced SAR (ASAR) (C‐band) data (24 scenes with VV and HH polarizations in Wide Swath [150 m]) during 2006‐2009 covering 500 km of the Louisiana coastal zone. Mapping was primarily based on a decrease in backscatter between reference and target scenes, and as an extension of previous studies, the flood inundation mapping performance was assessed by the degree of correspondence between inundation mapping and inland water levels. Both PALSAR‐ and ASAR‐based mapping at times were based on suboptimal reference scenes; however, ASAR performance seemed more sensitive to reference‐scene quality and other types of scene variability. Related to water depth, PALSAR and ASAR mapping accuracies tended to be lower when water depths were shallow and increased as water levels decreased below or increased above the ground surface, but this pattern was more pronounced with ASAR. Overall, PALSAR‐based inundation accuracies averaged 84% (n = 160), while ASAR‐based mapping accuracies averaged 62% (n = 245).     

Particulates and carbon monoxide pollution on production floor of steel recycling plant

For this study, particulates or particulate matter (PM) and carbon monoxide (CO) levels were monitored at different sections on the production floor of a scrap metal recycling factory. A Met‐One GT331 dust monitor and A Toxi‐Rae gas monitor were used to measure PM and CO concentrations, respectively. The 24‐hr averaging period concentrations of particulate matter having diameters of 2.5 microns or less in diameter (PM_2.5), particulate matter having diameters of 10 microns or less in diameter (PM₁₀), and total suspended particulates (TSP) within the plant ranged between 8.3 and 50.4 μg/m³, 12.0 and 151.3 μg/m³, and 30.0 and 285.0 μg/m³, respectively, while the maximum 8‐hr concentration of CO within the plant was 20.5 parts per million (ppm). The United States’ Environmental Protection Agency (US EPA) limits for PM_2.5, PM₁₀, and CO were exceeded only in the area around the furnace. Nigeria's Federal Ministry of Environment (FMENV), the World Health Organization (WHO), and the World Bank statutory limit for TSP were also exceeded in the area around the furnace. Toxicity potentials (TP) of the investigated pollutants were greater than 1.0 around the furnace, indicating that work spaces in proximity to the furnace could expose workers to adverse health conditions.     

Assessment of chlorophyll-a variations in high- and low-flow seasons in Apalachicola Bay by MODIS 250-m remote sensing

Chlorophyll-a (chl-a) is considered as a primary indicator for water quality and foods for oyster growth in Apalachicola estuarine ecosystem. Assessment of chl-a concentration variation in response to river inflow is important for estuarine environmental research and management. In this study, remote sensing analysis has been conducted to evaluate the effects of river inflow on chlorophyll concentrations in Apalachicola Bay of Florida in the northeast Gulf of Mexico. A remote sensing model for chl-a was improved and applied to map spatial distributions of chl-a by using Moderate Resolution Imaging Spectroradiometer (MODIS) 250-m resolution imageries in high-flow and low-flow seasons in 2001 and 2008. Chl-a values approximately ranged from the minimum 6 μg/l to the maximum 29 μg/l in the study period. Maximum chl-a concentration in high-flow season was almost twice above that in low-flow season. The averaged mean and minimum chl-a level in the high-flow season were approximately 42 and 28 % higher than those in low-flow season, respectively. The remote sensing mapping of chl-a was able to show spatial variations of chl-a in the entire bay under different flow conditions, which indicated its advantage over the traditional field data sampling for monitoring water quality over a large area of estuary. The MODIS 250-m remote sensing regression model presented from this study can be used to support monitoring and assessment of the spatial chl-a distribution in the bay for environmental research and management in Apalachicola Bay.     

Diel patterns of planktonic bioluminescence in the northern Sargasso Sea

Day-night changes in the vertical distribution, intensity, and size of bioluminescence flashes were investigated during a series of cruises to the northern Sargasso Sea in 1987 and 1988. Overall, depth integrated bioluminescence potential and flash density estimated from in situ measurements with a pumping bathyphotometer were 2 to 5 x higher at midnight than at midday. Depths from 50 to 100 m exhibited the most substantial day to night increases in bioluminescence potential and flash density. When classified by flash size (photon output per flash event), the increase from day to night was significant for all flash sizes, but was most dramatic for small flashes producing <7 x 10⁸ photons flash^-1. Bioluminescence potential and flash density increased 2 to 3 x during bathyphotometer measurements made at dusk. Bioluminescent light budgets estimated from day and night net collections in May and August 1987 also predicted 2.5 x higher nighttime than daytime mesoplankton bioluminescence. However, large bioluminescent taxa (mesoplankton) capable of significant vertical migrations only contributed on the order of 15% of the total bioluminescence in surface waters. Our results do not support the idea that most of the nightly increase in bioluminescence potential and flash density are due to vertical migration of bioluminescent organisms; rather they are consistent with an alternate view that photoinhibition of bioluminescent flashing by dinoflagellates may be primarily responsible for the diel patterns.     

Response and resilience of <Emphasis Type="Italic">Spartina alterniflora</Emphasis> to sudden dieback

We measured an array of biophysical and spectral variables to evaluate the response and recovery of Spartina alterniflora to a sudden dieback event in spring and summer 2004 within a low marsh in coastal Virginia, USA. S. alterniflora is a foundation species, whose loss decreases ecosystem services and potentiates ecosystem state change. Long-term records of the potential environmental drivers of dieback such as precipitation and tidal inundation did not evidence any particular anomalies, although Hurricane Isabel in fall 2003 may have been related to dieback. Transects were established across the interface between the dieback area and apparently healthy areas of marsh. Plant condition was classified based on ground cover within transects as dieback, intermediate and healthy. Numerous characteristics of S. alterniflora culms within each condition class were assessed including biomass, morphology and spectral attributes associated with photosynthetic pigments. Plants demonstrated evidence of stress in 2004 and 2005 beyond areas of obvious dieback and resilience at a multi-year scale. Resilience of the plants was evident in recovery of ground cover and biomass largely within 3 y, although a small remnant of dieback persisted for 8 y. Culms surviving within the dieback and areas of intermediate impact had modified morphological traits and spectral response that reflected stress. These morphometric and spectral differences among plant cover condition classes serve as guidelines for monitoring of dieback initiation, effects and subsequent recovery. Although a number of environmental and biotic parameters were assessed relative to causation, the reason for this particular dieback remains largely unknown, however.