Ground-Motion Prediction Equations for Central and Eastern North America (CENA)

First, a new path model, including the geometrical spreading and the quality factor functions, is developed for the New Madrid seismic zone (NMSZ) using recorded small and moderate earthquakes. The database consists of 500 broadband seismograms from 63 events of magnitude Mw 2.5 to 5.2. All the broadband stations are located within the Mississippi embayment. The vertical components of the records are processed and used to define the path effect term in the frequency range of 0.2 to 30 Hz. At distances less than 70 km, the spectral amplitudes decay as R-1; between 70 and 140 km, spectral amplitudes increase with distance and the geometric spreading is defined as R+0.25; beyond 140 km, the attenuation is described by R-0.5. The quality factor function is expressed as Q=614f0.32for frequencies greater than 1 Hz.Second, the horizontal-to-vertical component (H/V) spectral ratio is used as an estimation of the site response in the NMSZ. The observed average H/V ratios suggest site amplification between 2 and 4 in the low-frequency range (f\u3c5 Hz) for stations located on the lower shear-wave velocity deposits (Lowlands). The higher shear-wave velocity deposits (Uplands) indicate low-frequency amplification between 1.5 and 3 Hz. Comparison of the observed H/V ratios with the theoretical amplification factors suggest that the H/V ratios can be a first estimate of the site amplifications. Afterward, the variability of the H/V ratios with distance is examined and no discernible trends are found; therefore, the path effect model developed for the vertical ground motions in NMSZ using the database of this study is also applicable for the horizontal ground motions.Finally, a hybrid empirical method is used to develop a new ground-motion prediction equation (GMPE), for eastern North America (ENA), using five new GMPEs developed for western North America (WNA). A new GMPE is derived for a magnitude range of 5 to 8 and closest distances to the fault rupture up to 1000 km for hard-rock sites in ENA. The new GMPE is compared with two GMPEs used in the 2008 national seismic hazard maps as well as with available observed data for ENA

Pulmonary tuberculosis (TB) in pregnancy

Date of publication unknownIncludes bibliographical references.Date of publication unknownThis issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of pulmonary tuberculosis in pregnant women

Everyday Examples in Linear Algebra: Individual and Collective Creativity

This paper investigates creativity in students’ constructions of everyday examples about basis in Linear Algebra. We analyze semi-structured interview data with 18 students from the U.S. and Germany with diverse academic and social backgrounds. Our analysis of creativity in students’ everyday examples is organized into two parts. First, we analyze the range of students’ creative products by investigating the mathematical variability in the more commonly mentioned examples. Second, we unpack some of the collective processes in the construction of students’ examples. We examine how creativity was distributed through the interactions among the student, the interviewers, and other artifacts and ideas. Thus, in addition to contributing to the process vs. product discussion of creativity, our work also adds to the few existing studies that focus on collective mathematical creativity. The paper closes with connections to anti-deficit perspectives in mathematics education and some recommendations for individual and collective creativity in the classroom