Measurement of Rotational Events in Regions Prone to Seismicity: A Review

On the basis of the explanation of rotational seismology as an area of study, a modern approach to the seismic rotation in various continuum models is summarized. The aim of this chapter is to formulate the fundamental requirements for rotational seismometer. Consequently, a review of all existing technologies of rotational seismometers including mechanical, electrochemical, magnetohydrodynamical, as well as optical type solutions is discussed. The analysis of their parameters that considers technical requirements enforced by rotational seismology has indicated an optical instrument using a Sagnac interferometer as the best solution. Fibre-Optic System for Rotational Events & phenomena Monitoring (FOSREM) with its main parameters and features is described as an example of such solution. Moreover, the example of rotational events recorded in Książ observatory, Poland, using mechanical rotational seismometers and FOSREM is presented. There are data for M = 3.8 earthquake near Jarocin, Poland on the 2012.01.06 at 15:37:56 at a distance of about 200 km from Książ. Although the used devices have totally different designs, the results obtained using FOSREM and the results calculated by mechanical devices show compatibility in rotational signals

Talbot effect for the periodical object limited by a finite aperture

ABSTRACT: The communicate presents a new interpretation of the Talbot effect for periodical objects limited by finite apertures. According to the proposed approach, a self-image of a real, finite object is a superposition of deformed images of an elementary cell. The singular elementary cell image is equivalent to that formed in a proper optical system. The theoretical description makes possible to define a structure of self-images. Particularly, the approach enables a determination of apertures' dimensions which lead to self-images of a reasonable quality in a desired region of an image plane. The theory is illustrated and verified by numerical simulations

Equilateral hyperbolic moiré zone plates with variable focus obtained by rotations

We present equilateral hyperbolic zone plates with variable focal length, which are formed as moiré patterns by a mutual rotation of two identical basic grids. Among others, all principal zone plates, except of the spherical one, can be used as these basic transmittances. Three most important advantages of the proposed moiré zone plates are: a constant aperture of the created element during the mutual movement of basic grids, lack of aberrations due to their undesired mutual lateral displacements and high diffraction efficiency of the binary phase version. To obtain clearer moiré fringe pattern, a radial carrier frequency can be added additionally to the transmittances of basic grids. The destructive interference between both arms of the focal cross of the equilateral hyperbolic moiré zone plate can be obtained by a constant phase shift introduced in the transmittances of the basic grids. Potential applications of discussed elements are indicated, including the most promising one in the three-point alignment techniqueThis work was supported by the Network of Excellence on Micro-Optics (NEMO) and the programme CODI of the University of Antioquia, Medellin, ColombiaS

Intrapartum PCR assay is a fast and efficient screening method for Group B Streptococcus detection in pregnancy

Objectives: The aim of the study is to verify the usefulness of a real-time polymerase chain reaction versus the culture forante- and intrapartum group B Streptococcus maternal colonization (GBS) and prevalence of discordance during the periodbetween an antepartum screening and delivery.Material and methods: The study involved 106 pregnant women aged 18 to 39 years. Rectovaginal samples were collectedaccording to CDC guidelines at 35–37 weeks of gestation as well as in the first stage of labour, during physical examinationand were analyzed using two independent diagnostic methods: microbiological culture with standard culture andpolymerase chain reaction with real-time assay.Results: The discordance between antenatal and intrapartum GBS prevalence has been demonstrated as well as differencesassociated with diagnostic strategies, culture and PCR.Conclusions: Intrapartum detection of GBS colonization using culture or Real-Time PCR assay as well, regardless of antenatalscreening test for GBS, is very useful in identifying women who require implementation or withdrawal from prophylacticintrapartum antibiotic therapy. Real-Time PCR is a quick efficient method for GBS screening in pregnant women, whichcan be even applied during labor due to its short time of analyzing and high sensitivity and specificity. The above fact mayindicate the need to perform the GBS test in the intrapartum period in all pregnant GBS negative women using PCR assayas a more adequate diagnostic method as the procedure could reduce the risk of a neonatal GBS infection subsequentlyto a prophylactic antibiotic therapy in women with an intrapartum positive GBS

Talbot effect for periodical objects limited by finite apertures : a new interpretation

ABSTRACT: The paper presents a new interpretation of the Talbot effect for periodical objects limited by finite apertures. According to the proposed approach, a self-image of a real, finite object is a superposition of deformed images of an elementary cell. The singular elementary cell image is equivalent to that formed in a proper optical system. Two possible optical arrangements are discussed. The theoretical description makes possible to define a structure of selfimages. Particularly, the approach enables a determination of apertures’ dimensions, which lead to self-images of a reasonable quality in a desired region of an image plane. The theory is illustrated and verified by numerical simulations