The Role of a General Safety Requirement in Canada's Health Protection Regime

This research was supported in part by a financial contribution from the Health Policy Research Program, Health Canada

Effects of Longwall Mining on Hydrogeology, Leslie County, Kentucky Part 1: Pre-Mining Conditions

An investigation of the hydrologic effects of longwall coal mining is in progress in the Eastern Kentucky Coal Field. The study area is located in a first-order watershed in southern Leslie County over Shamrock Coal Company\u27s Beech Fork Mine (Edd Fork Basin on the Helton 7.5-minute quadrangle). Longwall panels approximately 700 feet wide are separated by three-entry gateways 200 feet wide. The mine is operating in the Fire Clay coal (Hazard No. 4); overburden thickness ranges from 300 to 1,000 feet. Mining in the watershed began in late summer 1993. Undermining of the instrumented panel (panel 7) is anticipated for summer 1994. This report documents pre-mining hydrogeologic conditions. Three sites over panel 7 (ridge-top, valley-side, and valley-bottom settings) were selected for intensive monitoring. An NX core hole was drilled at each site to provide stratigraphic control for well installation, to evaluate fractures, to conduct pressure-injection tests, and to provide a borehole for installation of time domain reflectometry cables. A rain gage and flume were installed in the basin in summer 1992. Twenty-four monitoring wells, completed in July 1992, provide water-level and water-quality data on individual stratigraphic zones represented by the three well locations. Interpretation of pre-mining conditions was used to develop a conceptual model of ground-water flow in the study basin. Three ground-water zones were identified on the basis of hydraulic properties. The shallow-fracture zone, a highly conductive region parallel to the ground surface, extends to a depth of 60 to 70 feet. The elevation-head zone includes the ridge interior, mostly above drainage, where total head consists of elevation head only. The pressure head zone, largely below drainage, is the region where total head is the sum of elevation head and pressure head. Two fresh-water geochemical facies are also present. Shallow ground water is a calcium-magnesium-bicarbonatesulfate type, whereas ground water in the deeper regional system is sodium-bicarbonate type. Anticipated effects from longwall mining include a decrease in water levels in the pressure-head zone. Temporary decreases are expected in the shallow-fracture zone as newly created void spaces subsequently fill. The elevation-head zone should not be greatly affected because it is predicted to be in the aquiclude zone

Effects of Longwall Mining on Hydrogeology, Leslie County, Kentucky Part 3: Post-Mining Conditions

The effects of longwall coal mining on hydrology in the Eastern Kentucky Coal Field have been investigated since 1991. The study area is in the Edd Fork watershed in southern Leslie County, over Shamrock Coal Company\u27s Beech Fork Mine. Longwall panels approximately 700 ft wide are separated by three-entry gateways that are approximately 200 ft wide. The mine is operated in the Fire Clay (Hazard No. 4) coal; overburden thickness ranges from 300 to 800 ft. Mining began in panel 1 in September 1991 and concluded with panel 8 in September 1994. Long-term monitoring consisting of a network of piezometers and time-domain reflectometry (TDR) cables previously installed over panel 7, in conjunction with a continuously recording rain gage and flume, began after the completion of mining. Two new core holes were drilled over panel 7 approximately 1 year after mining ceased in panel 8 to determine depth of collapse and hydraulic conductivity of strata. Water levels were measured in two new monitoring wells installed after mining to complement the 11 piezometers installed prior to mining that were still functioning. Precipitation was measured through July 1996, and streamflow was measured in Edd Fork on a monthly basis using a cross-section gaging method. Physical failure of piezometers, core drilling, and the movement of air into deeper piezometers after mining indicate that extensive fracturing occurred to a height of 450 ft above the mine, which is approximately 60 times the extracted coal-seam thickness. Hydraulic conductivity values determined from pressure-injection tests were 10 to 100 times greater after mining than before mining; many values were in the range of 10-2 to 10-4 ft/min for all lithologies. At a minimum, a zone of rock approximately 200 ft above the mined coal was dewatered beneath Edd Fork. Ground-water levels in ridgetop piezometers fluctuated slightly more after mining than they did before, which indicates that the upper part of the ridge is more hydraulically connected to surface recharge from precipitation since mining took place. The existence of ground water in the shallow ridgetop piezometers suggests that an underlying aquitard zone developed during mine collapse, which retards the downward movement of shallow ground water to the mined-out area. Water level declined in a sandstone unit approximately 300 ft above the mine after mining, but recovered within a year. This indicates that the underlying regional aquitard still retards downward ground-water movement, despite the hydraulic conductivity of the unit increasing 100 times after mining. Edd Fork, approximately 375 ft above the mine in panel 7, resumed surface flow 2 months after completion of mining; however, flow diminishes downstream at about the centerline of panel 8. Mining is still active in other areas of the mine, and mechanical dewatering activities will most likely keep water levels in the deep zones artificially depressed in the study area until mining is completed and dewatering activities cease

Effects of Longwall Mining on Hydrology, Leslie County, Kentucky Part 2: During-Mining Conditions

The effects of longwall coal mining on hydrology in the Eastern Kentucky Coal Field are being investigated. The study area is in the Edd Fork watershed in southern Leslie County, over Shamrock Coal Company\u27s Beech Fork Mine. Longwall panels approximately 700 ft wide are separated by three-entry gateways that are approximately 200 ft wide. The mine is operated in the Fire Clay (Hazard No. 4) coal; overburden thickness ranges from 300 to 800 ft. Mining began in panel 1 in September 1991 and concluded with panel 8 in September 1994. Long-term monitoring consisting of a network of piezometers and time-domain reflectometry (TDR) cables previously installed over panel 7, in conjunction with a continuously recording rain gage and flume, is continuing after the completion of mining. Mining in panel 5 affected water levels in three of 24 piezometers installed over panel 7; the level went down in one piezometer and rose in two. Mining in panel 6 affected 16 of 24 piezometers; the level went down in 11 piezometers and rose in five. Mining in panel 7 affected water levels in 20 of 24 piezometers. Different water-level responses were recorded as the mine approached and passed by the instrumental sites. Thirteen piezometers failed as a result of undermining. These piezometers penetrated the zone of deep fracturing that extends upward approximately 450 ft (or 60 times greater than the mined thickness) above the mine. Only one piezometer showed a net increase in water level as a result of mining. Mining-induced surface fractures, observed along roads in the watershed, were generally parallel to the slope of the land surface or mining direction and probably contributed to ground-water recharge. The surface stream was unaffected until it was undermined by panel 8; then the stream went dry. TDR cables in the Hazard coal zone were deformed as mining passed by on the adjacent panel. Water levels in piezometers in the Hazard coal zone declined at the same time. TDR cables broke completely twice. The deepest complete break was in the Hazard coal zone and occurred when the active mine face was approaching, but still approximately 1,000 ft away from, the affected cable in panel 7. This corresponds to an angle of influence of 60 to 70°. Rock broke in the shallow subsurface (less than 50 ft deep) when the cable was directly undermined. Water-level responses in piezometers adjacent to mining are related to the complex flow system, rather than a defined angle of hydrologic influence. Coal beds and other conductive strata transmit water-level responses as far away as 1,450 ft, whereas nonconductive strata transmit little water-level change at closer distances. The water-level responses observed in this study support existing subsidence models. Piezometers in the zone of intensive fracturing failed as a result of rock breakage. An aquiclude zone developed in the ridge. The integrity of strata and piezometers was generally maintained. The most variable effects were observed in the zone of surface fracturing, within 50 ft of the surface

Systemic Effects of Arctic Pollutants in Beluga Whales Indicated by CYP1A1 Expression

Cytochrome P450 1A1 (CYP1A1) is induced by exposure to polycyclic aromatic hydrocarbons (PAHs) and planar halogenated aromatic hydrocarbons (PHAHs) such as non-ortho polychlorinated biphenyls (PCBs). In this study, we examined CYP1A1 protein expression immunohistochemically in multiple organs of beluga whales from two locations in the Arctic and from the St. Lawrence estuary. These beluga populations have some of the lowest (Arctic sites) and highest (St. Lawrence estuary) concentrations of PCBs in blubber of all cetaceans. Samples from these populations might be expected to have different contaminant-induced responses, reflecting their different exposure histories. The pattern and extent of CYP1A1 staining in whales from all three locations were similar to those seen in animal models in which CYP1A has been highly induced, indicating a high-level expression in these whales. CYP1A1 induction has been related to toxic effects of PHAHs or PAHs in some species. In St. Lawrence beluga, the high level of CYP1A1 expression coupled with high levels of contaminants (including CYP1A1 substrates, e.g., PAH procarcinogens potentially activated by CYP1A1) indicates that CYP1A1 could be involved in the development of neoplastic lesions seen in the St. Lawrence beluga population. The systemic high-level expression of CYP1A1 in Arctic beluga suggests that effects of PAHs or PHAHs may be expected in Arctic populations, as well. The high-level expression of CYP1A1 in the Arctic beluga suggests that this species is highly sensitive to CYP1A1 induction by aryl hydrocarbon receptor agonists

Leveraging Pleiotropy to Discover and interpret Gwas Results For Sleep-Associated Traits

Genetic association studies of many heritable traits resulting from physiological testing often have modest sample sizes due to the cost and burden of the required phenotyping. This reduces statistical power and limits discovery of multiple genetic associations. We present a strategy to leverage pleiotropy between traits to both discover new loci and to provide mechanistic hypotheses of the underlying pathophysiology. Specifically, we combine a colocalization test with a locus-level test of pleiotropy. In simulations, we show that this approach is highly selective for identifying true pleiotropy driven by the same causative variant, thereby improves the chance to replicate the associations in underpowered validation cohorts and leads to higher interpretability. Here, as an exemplar, we use Obstructive Sleep Apnea (OSA), a common disorder diagnosed using overnight multi-channel physiological testing. We leverage pleiotropy with relevant cellular and cardio-metabolic phenotypes and gene expression traits to map new risk loci in an underpowered OSA GWAS. We identify several pleiotropic loci harboring suggestive associations to OSA and genome-wide significant associations to other traits, and show that their OSA association replicates in independent cohorts of diverse ancestries. By investigating pleiotropic loci, our strategy allows proposing new hypotheses about OSA pathobiology across many physiological layers. For example, we identify and replicate the pleiotropy across the plateletcrit, OSA and an eQTL of DNA primase subunit 1 (PRIM1) in immune cells. We find suggestive links between OSA, a measure of lung function (FEV1/FVC), and an eQTL of matrix metallopeptidase 15 (MMP15) in lung tissue. We also link a previously known genome-wide significant peak for OSA in the hexokinase 1 (HK1) locus to hematocrit and other red blood cell related traits. Thus, the analysis of pleiotropic associations has the potential to assemble diverse phenotypes into a chain of mechanistic hypotheses that provide insight into the pathogenesis of complex human diseases

A ten-year follow-up of a study of memory for the attack of September 11, 2001: Flashbulb memories and memories for flashbulb events.

Within a week of the attack of September 11, 2001, a consortium of researchers from across the United States distributed a survey asking about the circumstances in which respondents learned of the attack (their flashbulb memories) and the facts about the attack itself (their event memories). Follow-up surveys were distributed 11, 25, and 119 months after the attack. The study, therefore, examines retention of flashbulb memories and event memories at a substantially longer retention interval than any previous study using a test-retest methodology, allowing for the study of such memories over the long term. There was rapid forgetting of both flashbulb and event memories within the first year, but the forgetting curves leveled off after that, not significantly changing even after a 10-year delay. Despite the initial rapid forgetting, confidence remained high throughout the 10-year period. Five putative factors affecting flashbulb memory consistency and event memory accuracy were examined: (a) attention to media, (b) the amount of discussion, (c) residency, (d) personal loss and/or inconvenience, and (e) emotional intensity. After 10 years, none of these factors predicted flashbulb memory consistency; media attention and ensuing conversation predicted event memory accuracy. Inconsistent flashbulb memories were more likely to be repeated rather than corrected over the 10-year period; inaccurate event memories, however, were more likely to be corrected. The findings suggest that even traumatic memories and those implicated in a community's collective identity may be inconsistent over time and these inconsistencies can persist without the corrective force of external influences.This is the author accepted manuscript. The final version is available from the American Psychological Association via http://dx.doi.org/10.1037/xge000005

Association of Genetic Loci with Sleep Apnea in European Americans and African-Americans: The Candidate Gene Association Resource (CARe)

Although obstructive sleep apnea (OSA) is known to have a strong familial basis, no genetic polymorphisms influencing apnea risk have been identified in cross-cohort analyses. We utilized the National Heart, Lung, and Blood Institute (NHLBI) Candidate Gene Association Resource (CARe) to identify sleep apnea susceptibility loci. Using a panel of 46,449 polymorphisms from roughly 2,100 candidate genes on a customized Illumina iSelect chip, we tested for association with the apnea hypopnea index (AHI) as well as moderate to severe OSA (AHI≥15) in 3,551 participants of the Cleveland Family Study and two cohorts participating in the Sleep Heart Health Study. Among 647 African-Americans, rs11126184 in the pleckstrin (PLEK) gene was associated with OSA while rs7030789 in the lysophosphatidic acid receptor 1 (LPAR1) gene was associated with AHI using a chip-wide significance threshold of p-value<2×$10^{−6}$. Among 2,904 individuals of European ancestry, rs1409986 in the prostaglandin E2 receptor (PTGER3) gene was significantly associated with OSA. Consistency of effects between rs7030789 and rs1409986 in LPAR1 and PTGER3 and apnea phenotypes were observed in independent clinic-based cohorts. Novel genetic loci for apnea phenotypes were identified through the use of customized gene chips and meta-analyses of cohort data with replication in clinic-based samples. The identified SNPs all lie in genes associated with inflammation suggesting inflammation may play a role in OSA pathogenesis

Long-Term Memory for the Terrorist Attack of September 11: Flashbulb Memories, Event Memories, and the Factors That Influence Their Retention

More than 3,000 individuals from 7 U.S. cities reported on their memories of learning of the terrorist attacks of September 11, as well as details about the attack, 1 week, 11 months, and/or 35 months after the assault. Some studies of flashbulb memories examining long-term retention show slowing in the rate of forgetting after a year, whereas others demonstrate accelerated forgetting. This article indicates that (a) the rate of forgetting for flashbulb memories and event memory (memory for details about the event itself) slows after a year, (b) the strong emotional reactions elicited by flashbulb events are remembered poorly, worse than nonemotional features such as where and from whom one learned of the attack, and (c) the content of flashbulb and event memories stabilizes after a year. The results are discussed in terms of community memory practices.James S. McDonnell FoundationNational Institutes of Health (U.S.) (grant R01- MH0066972

Heliogyro Solar Sail Research at NASA

The recent successful flight of the JAXA IKAROS solar sail has renewed interest within NASA in spinning solar sail concepts for high-performance solar sailing. The heliogyro solar sail, in particular, is being re-examined as a potential game-changing architecture for future solar sailing missions. In this paper, we present an overview of ongoing heliogyro technology development and feasibility assessment activities within NASA. In particular, a small-scale heliogyro solar sail technology demonstration concept will be described. We will also discuss ongoing analytical and experimental heliogyro structural dynamics and controls investigations and provide an outline of future heliogyro development work directed toward enabling a low cost heliogyro technology demonstration mission ca. 2020