Massachusetts Depth to Bedrock Project

The depth to bedrock is perhaps one of the most important surfaces that is fundamental to many practical engineering and geological problems. Yet it is not well understood everywhere. Knowing the depth to bedrock for transportation projects not only influences cost but may also affect selection of the appropriate foundation system for a particular structure. Furthermore, estimates of the bedrock depth, along with the type of overburden (e.g., glacial till, varved clay, sand and gravel) help determine the most appropriate subsurface investigation method to use during project planning, and reduces construction delays and claims brought forward by contractors. Accordingly, there is some level of uncertainty in planning subsurface investigations for any transportation project when depth to bedrock information is lacking. This project is an attempt to reduce the uncertainty in highway project planning by providing interpolated statewide data layers of the depth to bedrock and bedrock altitude at 100-meter resolution based on currently available subsurface data. In addition, maps depicting the level of confidence in the estimate of the bedrock altitude and depth are also provided. The confidence is based on both the interpolated prediction standard error as well as the measurement uncertainties associated with the input data

Lineaments: Their value in assessing groundwater availability and quality in bedrock aquifers of glaciated metamorphic terrains. A case study

A lineament analysis for Georgetown, Maine, a 44 km\sp2 island community situated on the central Maine coast, was performed to evaluate the relationship between mapped lineaments and (1) outcrop fractures, (2) well productivity (35 wells), and (3) groundwater quality determined from a sample of 87 existing bedrock wells. Lineaments were drawn by three observers using two scales of imagery (SLAR and a 1:80,000 Aerial Photograph). Rigorous reproducibility testing indicates that the ability of individual observers to reproduce lineaments at the same geographic location is low; more than 55% of all lineaments mapped by any observer were not reproducible. This casts doubt as to how many lineaments may be considered real features. In addition, when azimuthal sets of near-vertical outcrop fractures are compared with reproducible lineament domains of similar azimuth on a regional basis, distinct areas of overlap are defined across the island. The extent of this overlap is not uniform. Some lineament domains (165\sp\circ) exhibit no correlation with fracture fabric whereas other lineament domains (120\sp\circ) only show a correlation with fracture fabric in a very limited geographic area. In regard to well productivity, wells located on lineaments, specifically those lineaments showing a geographic correlation with similar-trending fracture domains, are generally more productive than non-lineament wells. If the same analysis is repeated, but is performed without considering whether or not the lineaments used in the analysis are geographically correlative with fracture domains, no differences are observed between the productivities of lineament and non-lineament wells. However, in this study, other geologic factors exhibit strong influences on high productivity in bedrock wells. Bedrock type (amphibolite) is the dominant and only statistically significant influence on well productivity followed by depth to the water table (shallow depths), proximity to lineaments (specifically those that correlate geographically with outcrop fractures), topographic position (flatter hydraulic gradients), and proximity to surface water bodies, in order of decreasing importance. Groundwater chemistry is controlled primarily by bedrock type, topographic setting, structural position, and overburden type and thickness. The chemical character of groundwater sampled from bedrock wells is generally not influenced by the proximity of a well to a lineament

Implementation Plan of the National Cooperative Geologic Mapping Program Strategy—Northeast Region of the United States: New York and New England

Complexly deformed igneous, metamorphic, and sedimentary rocks form the bedrock of the Northeast region of the United States. Variably thick unconsolidated sediments deposited by glacial, fluvial, and eolian systems locally cover the bedrock. New geologic mapping focuses on areas lacking modern, detailed studies or syntheses, and contributes to existing framework research. This report addresses plans for the continued development of regionally and nationally consistent geologic maps and map databases, efforts to answer outstanding geologic questions, and societal concerns associated with related geologic topics, such as hazards, geologic and hydrologic resources, and environmental issues

Edoxaban versus warfarin in patients with atrial fibrillation

Contains fulltext : 125374.pdf (publisher's version ) (Open Access)BACKGROUND: Edoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. METHODS: We conducted a randomized, double-blind, double-dummy trial comparing two once-daily regimens of edoxaban with warfarin in 21,105 patients with moderate-to-high-risk atrial fibrillation (median follow-up, 2.8 years). The primary efficacy end point was stroke or systemic embolism. Each edoxaban regimen was tested for noninferiority to warfarin during the treatment period. The principal safety end point was major bleeding. RESULTS: The annualized rate of the primary end point during treatment was 1.50% with warfarin (median time in the therapeutic range, 68.4%), as compared with 1.18% with high-dose edoxaban (hazard ratio, 0.79; 97.5% confidence interval [CI], 0.63 to 0.99; P<0.001 for noninferiority) and 1.61% with low-dose edoxaban (hazard ratio, 1.07; 97.5% CI, 0.87 to 1.31; P=0.005 for noninferiority). In the intention-to-treat analysis, there was a trend favoring high-dose edoxaban versus warfarin (hazard ratio, 0.87; 97.5% CI, 0.73 to 1.04; P=0.08) and an unfavorable trend with low-dose edoxaban versus warfarin (hazard ratio, 1.13; 97.5% CI, 0.96 to 1.34; P=0.10). The annualized rate of major bleeding was 3.43% with warfarin versus 2.75% with high-dose edoxaban (hazard ratio, 0.80; 95% CI, 0.71 to 0.91; P<0.001) and 1.61% with low-dose edoxaban (hazard ratio, 0.47; 95% CI, 0.41 to 0.55; P<0.001). The corresponding annualized rates of death from cardiovascular causes were 3.17% versus 2.74% (hazard ratio, 0.86; 95% CI, 0.77 to 0.97; P=0.01), and 2.71% (hazard ratio, 0.85; 95% CI, 0.76 to 0.96; P=0.008), and the corresponding rates of the key secondary end point (a composite of stroke, systemic embolism, or death from cardiovascular causes) were 4.43% versus 3.85% (hazard ratio, 0.87; 95% CI, 0.78 to 0.96; P=0.005), and 4.23% (hazard ratio, 0.95; 95% CI, 0.86 to 1.05; P=0.32). CONCLUSIONS: Both once-daily regimens of edoxaban were noninferior to warfarin with respect to the prevention of stroke or systemic embolism and were associated with significantly lower rates of bleeding and death from cardiovascular causes. (Funded by Daiichi Sankyo Pharma Development; ENGAGE AF-TIMI 48 ClinicalTrials.gov number, NCT00781391.)