Crosshole Seismic Tomography and Borehole Logging for Engineering Site Characterization in Sikeston, MO, USA

This paper presents a geophysical investigation performed in the median separating the east and west bound lanes of U.S. Highway 60, approximately 15 km west from the town of Sikeston, MO, USA. Two boreholes, drilled at depth of 45 m, approximately located 6 m from the Wahite Ditch Bridge in U.S. Highway 60, were used to carry out the geophysical tests. The objective of the survey was to obtain the density distribution of soil materials and high-resolution compressional and shear wave velocities of the shallow subsurface for computation of elastic engineering properties of the unconsolidated material interposed between the two investigated boreholes. The studied site is located in the New Madrid Seismic Zone (NMSZ), one of the major seismic source zones in the eastern United States. Although no major seismic events have occurred in the New Madrid area since the catastrophic earthquakes of 1811-1812, more intensive studies in this area are required to better understand the local soil effects and the liquefaction potential of unconsolidated earth materials on strong ground motion. Joint interpretation of borehole logs and velocity images obtained by P- and S-wave traveltime inversions outlined shallow anomalies, which were interpreted as caused by variation in relative porosity and compactness of saturated unconsolidated soil materials. In the interval between 17 and 19 m of depth, a velocity anomaly with distinct characteristics is recognized. Analysis of traveltimes of P-wave energy propagated from common source-receiver depth positions at that depth interval delineated a low velocity zone (lower than estimated P-wave velocity in water) in which propagated S-wave energy was negligible. Analysis of porosity logs did not outline any porosity anomaly for that region. The anomaly is interpreted as caused by the presence of a gas-bearing zone extending for 1.5 m (+0.76 m from the top and the bottom of the depth interval), through which propagation of shear energy was almost prevented and compressional energy traveled a very low speed. Relative lower values of shear modulus were computed for the gas-bearing zone; the same depth interval also exhibited relative lower values of bulk modulus, relative higher values of compressibility and relative high porosity. However, the low velocity anomaly is not caused by relative increased porosity but rather to replacement of water by gas in the pore volumes of this zone. The presence of a shallow thin gas-bearing zone is interpreted as hazardous in the occurrence of strong motion in the New Madrid Seismic Zone. Shallow water table, as detected by seismic and log measurements in the area, increases the risk of liquefaction of the sampled soil under strong ground motions

Abstracts from the 23rd Italian congress of Cystic Fibrosis and the 13th National congress of Cystic Fibrosis Italian Society

Cystic Fibrosis (CF) occurs most frequently in caucasian populations. Although less common, this disorder have been reported in all the ethnicities. Currently, there are more than 2000 described sequence variations in CFTR gene, uniformly distributed and including variants pathogenic and benign (CFTR1:www.genet.sickkids.on.ca/). To date,only a subset have been firmily established as variants annotated as disease-causing (CFTR2: www.cftr2.org). The spectrum and the frequency of individual CFTR variants, however, vary among specific ethnic groups and geographic areas. Genetic screening for CF with standard panels of CFTR mutations is widely used for the diagnosis of CF in newborns and symptomatic patients, and to diagnose CF carrier status. These screening panels have an high diagnostic sensitivity (around 85%) for CFTR mutations in caucasians populations but very low for non caucasians. Developed in the last decade, Next-Generation Sequencing (NGS) has been the last breakthrough technology in genetic studies with a substantial reduction in cost per sequenced base and a considerable enhancement of the sequence generation capabilities. Extended CFTR gene sequencing in NGS includes all the coding regions, the splicing sites and their flankig intronic regions, deep intronic regions where are localized known mutations,the promoter and the 5'-3' UTR regions. NGS allows the analysis of many samples concurrently in a shorter period of time compared to Sanger method . Moreover, NGS platforms are able to identify CFTR copy number variation (CNVs), not detected by Sanger sequencing. This technology has provided new and reliable approaches to molecular diagnosis of CF and CFTR-Related Disorders. It also allows to improve the diagnostic sensitivity of newborn and carrier screeningmolecular tests. In fact, bioinformatics tools suitable for all the NGS platforms can filter data generated from the gene sequencing, and analyze only mutations with well-established disease liability. This approach allows the development of targeted mutations panels with a higher number of frequent CF mutations for the target populationcompared to the standard panels and a consequent enhancement of the diagnostic sensitivity. Moreover, in the emerging challenge of diagnosing CF in non caucasians patients, the possibility of customize a NGS targeted mutations panel should increase the diagnostic sensitivity when the target population has different ethnicities