Seismic Wave Propagation Characteristics and Their Effects on the Dynamic Response of Layered Rock Sites

To investigate the seismic response of layered rock sites, a multidomain analysis method was proposed. Three finite element models with infinite element boundaries for layered sites were analysed. The results of this multidomain analysis show that stratum properties and elevation have an impact on wave propagation characteristics and the dynamic response of layered sites. Compared with the rock mass, the overlying gravel soil has a greater dynamic amplification effect at the sites. A time domain analysis parameter PGA(IMF) was proposed to analyse the effects of different strata on the seismic magnification effect of layered sites, and its application was also discussed in comparison with PGA. According to the frequency domain analysis, the interface of the rock mass strata has a low impact on the Fourier spectrum characteristics of the sites, but gravel soil has a great magnification effect on the spectrum amplitude in the high-frequency band (≥30 Hz) of waves. Moreover, the stratum properties have a great influence on the shape and peak value of the Hilbert energy and marginal spectrum at layered sites. When waves propagate from hard rock to soft rock, the peak value of the Hilbert energy spectrum changes from single to multiple peaks; then, in gravelly soil, the Hilbert energy spectral peak, its nearby amplitude and the amplitude in the high-frequency band (28–36 Hz) are obviously amplified. The frequency components and amplitude of the marginal spectrum become more abundant and larger from rock to gravelly soil in the high-frequency band (28–35 Hz).

Magnification effect on fine motor skills of dental students

Objectives This study observed the effect of different magnification systems on dental students’ real and perceived fine motor skills. Methods This was a laboratory-based experimental study. Students in the fifth year of an undergraduate dentistry program (N = 92) participated in this study. The dependent variables were real motor skills, perceived motor skills and time required to complete the fine motor skills test. The independent variable was the use of a magnification system under four conditions. For each condition, the Dental Manual Dexterity Assessment was performed, which consisted of inserting the #3195FF bur into targets positioned on a Styrofoam plate. The accuracy of each penetration of the targets was scored, using a point system with a maximum possible score of 246 points. Students’ perceived fine motor skills were assessed using a visual analog scale (VAS) that ranged from zero for no skills to ten for maximum skills. A descriptive statistical analysis and the repeated measures ANOVA were performed (α = 0.05). Results The Galilean and Keplerian loupes were found to positively affect students’ real fine motor skills (p<0.01); however, perceived fine motor skills and time were significantly better (p<0.01) under the naked eye. Conclusions Dental students’ real fine motor skills were better when Galilean and Keplerian loupes were used, but the perceived fine motor skills were not.

Resolution-Enhancing Structure for the Electric Field Microsensor Chip

Electrostatic voltage is a vital parameter in industrial production lines, for reducing electrostatic discharge harms and improving yields. Due to such drawbacks as package shielding and low resolution, previously reported electric field microsensors are still not applicable for industrial static monitoring uses. In this paper, we introduce a newly designed microsensor package structure, which enhances the field strength inside the package cavity remarkably. This magnification effect was studied and optimized by both theoretical calculation and ANSYS simulation. By means of the digital synthesizer and digital coherent demodulation method, the compact signal processing circuit for the packaged microsensor was also developed. The meter prototype was calibrated above a charged metal plate, and the electric field resolution was 5 V/m, while the measuring error was less than 3 V, from −1 kV to 1 kV in a 2 cm distance. The meter was also installed into a production line and showed good consistency with, and better resolution than, a traditional vibratory capacitance sensor.

Fake dark matter from retarded distortions

We push ahead the idea developed in a previous work, that some fraction of the dark matter and the dark energy can be explained as a relativistic effect. The inhomogeneity matter generates gravitational distortions, which are general relativistically retarded. These combine in a magnification effect since the past matter density, which generated the distortion we feel now, is greater than the present one. The non negligible effect on the averaged expansion of the universe contributes both to the estimations of the dark matter and to the dark energy, so that the parameters of the Cosmological Standard Model need some corrections. In this second work we apply the previously developed framework to relativistic models of the universe. It results that one parameter remain free, so that more solutions are possible, as function of inhomogeneity. One of these fully explains the dark energy, but requires more dark matter than the Cosmological Standard Model ($$91\%$$ 91 % of the total matter). Another solution fully explains the dark matter, but requires more dark energy than the Cosmological Standard Model ($$15\%$$ 15 % more). A third noteworthy solution explains a consistent part of the dark matter ($$63\%$$ 63 % of the total matter) and also some of the dark energy ($$4\%$$ 4 % ).

Trade and Uncertainty

We offer a new explanation as to why international trade is so volatile in response to economic shocks. Our approach combines the idea of uncertainty shocks with international trade. Firms order inputs from home and foreign suppliers. In response to an uncertainty shock firms disproportionately cut orders of foreign inputs due to higher fixed costs. In the aggregate, this leads to a bigger contraction in international trade flows than in domestic activity, a magnification effect. We confront the model with newly compiled US import and industrial production data. Our results help to explain the Great Trade Collapse of 2008–2009.

Magnification Effect of Foveal Avascular Zone Measurement Using Optical Coherence Tomography Angiography

Purpose: The aim of this study was to evaluate the foveal avascular zone (FAZ) of healthy subjects and examine the magnification effect. Methods: A total of 33 healthy volunteers were enrolled and all subjects were eligible for analysis. Optical coherence tomography angiography (OCTA) examination scanned 3 × 3 mm of the macular area. The FAZ area was measured on the superficial OCTA en face image with and without correction by axial length. The relationship between changes in the FAZ area after correction with the axial length was examined. Results: The mean age was 21.9 ± 0.6 years. The mean axial length was 24.87 ± 1.17 mm and mean spherical equivalent (SE) value was –3.64 ± 2.83 diopters (D). The FAZ area was 0.26 ± 0.10 mm2 before the axial length correction and 0.27 ± 0.10 mm2 after the correction. In the eyes that had an axial length longer than or equal to 26 mm or SE less than or equal to –6 D, the FAZ area after correction was significantly larger than that before correction (p < 0.01). The change of FAZ area after correction with axial length was significantly correlated with the axial length (R2 = 0.88, p < 0.01) or SE value (R2 = 0.55, p < 0.01). Conclusion: FAZ areas were comparable to previous reports. In high myopic cases, the magnification effect needs to be considered when evaluating the FAZ area.

A Novel Method to Calculate Objects’ Apparent Size

The angular diameter is the angle subtended by a generic object &ndash; an apple or a star &ndash; to the eye of an observer, and it describes how large the object appears from a given viewpoint. The angular diameter represents a powerful tool for distance calculations starting from directly measurable information and it finds application in several contexts varying from cosmography to architecture. In this article, the author proposes a novel equation to calculate the apparent diameter of whatever object. This equation defines a relation between the initial distance R0 at which the observed object is located and the object&rsquo;s apparent diameter. Based on the preliminary tests conducted, the model seems to faithfully portrait this relation with respect to measured values, also at the astronomical scale, thus considering the Earth-Moon distance, where, the absolute error detected is about 0.56%. The tests highlighted also a dependency between the results accuracy and the measurement conditions suggesting a high level of sensibility linked to the initial magnification effect produced by the retina or the artificial lens employed.

Prospects for cosmic magnification measurements using H i intensity mapping

ABSTRACT We investigate the prospects of measuring the cosmic magnification effect by cross-correlating neutral hydrogen intensity mapping (H i IM) maps with background optical galaxies. We forecast the signal-to-noise ratio for H i IM data from SKA1-MID and HIRAX, combined with LSST photometric galaxy samples. We find that, thanks to their different resolutions, SKA1-MID and HIRAX are highly complementary in such an analysis. We predict that SKA1-MID can achieve a detection with a signal-to-noise ratio of ∼15 on a multipole range of ℓ ≲ 200, while HIRAX can reach a signal-to-noise ratio of ∼50 on 200 &lt; ℓ &lt; 2000. We conclude that measurements of the cosmic magnification signal will be possible on a wide redshift range with foreground H i intensity maps up to z ≲ 2, while optimal results are obtained when 0.6 ≲ z ≲ 1.3. Finally, we perform a signal to noise analysis that shows how these measurements can constrain the H i parameters across a wide redshift range.

The importance of magnification effects in galaxy-galaxy lensing

Magnification changes the observed local number density of galaxies on the sky. This biases the observed tangential shear profiles around galaxies: the so-called galaxy-galaxy lensing (GGL) signal. Inference of physical quantities, such as the mean mass profile of halos around galaxies, are correspondingly affected by magnification effects. We used simulated shear and galaxy data from the Millennium Simulation to quantify the effect on shear and mass estimates from the magnified lens and source number counts. The former is due to the large-scale matter distribution in the foreground of the lenses; the latter is caused by magnification of the source population by the matter associated with the lenses. The GGL signal is calculated from the simulations by an efficient fast Fourier transform, which can also be applied to real data. The numerical treatment is complemented by a leading-order analytical description of the magnification effects, which is shown to fit the numerical shear data well. We find the magnification effect is strongest for steep galaxy luminosity functions and high redshifts. For a KiDS+VIKING+GAMA-like survey with lens galaxies at redshift zd = 0.36 and source galaxies in the last three redshift bins with a mean redshift of ¯zs = 0.79, the magnification correction changes the shear profile up to 2%, and the mass is biased by up to 8%. We further considered an even higher redshift fiducial lens sample at zd = 0.83, with a limited magnitude of 22 mag in the r-band and a source redshift of zs = 0.99. Through this, we find that a magnification correction changes the shear profile up to 45% and that the mass is biased by up to 55%. As expected, the sign of the bias depends on the local slope of the lens luminosity function αd, where the mass is biased low for αd < 1 and biased high for αd > 1. While the magnification effect of sources is rarely more than 1% of the measured GGL signal, the statistical power of future weak lensing surveys warrants correction for this effect.