Segmented compressed sampling for analog-to-information conversion: Method and performance analysis

A new segmented compressed sampling method for analog-to-information conversion (AIC) is proposed. An analog signal measured by a number of parallel branches of mixers and integrators (BMIs), each characterized by a specific random sampling waveform, is first segmented in time into $M$ segments. Then the sub-samples collected on different segments and different BMIs are reused so that a larger number of samples than the number of BMIs is collected. This technique is shown to be equivalent to extending the measurement matrix, which consists of the BMI sampling waveforms, by adding new rows without actually increasing the number of BMIs. We prove that the extended measurement matrix satisfies the restricted isometry property with overwhelming probability if the original measurement matrix of BMI sampling waveforms satisfies it. We also show that the signal recovery performance can be improved significantly if our segmented AIC is used for sampling instead of the conventional AIC. Simulation results verify the effectiveness of the proposed segmented compressed sampling method and the validity of our theoretical studies.Comment: 32 pages, 5 figures, submitted to the IEEE Transactions on Signal Processing in April 201

Antioxidant activity in some Iranian seaweed species from Chabahar

The antioxidant activities of Ulva faciata, Nizimuddinia zanardinii and Gracilaria corticata were investigated in Chabahar, Iran. Methanol extract and n-hexane, dichloromethane and ethylacetate fractions used for antioxidative properties test by the total antioxidative activity, 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) free radical scavenging activity, reduction power, metal chelating activity and inhibition of lipid peroxidation methods. The methanolic extracts of three seaweed species showed lower antioxidative properties. The most effective antioxidant properties were observed from the EA fractions of G. corticata and U. faciata. dichloromethane (DCM), fraction of N. zanardinii showed significantly higher total antioxidative activity, DPPH radical scavenging and power reduction in comparison to its n-hexane, EA fractions and crude MeOH extract. There was a strong correlation between the reduction power (r^2=0.94) and the total phenolic content of the seaweeds extracts and fractions. The results indicate U. faciata and G. corticata can be potential sources of natural antioxidants and may be efficiently used as nutraceuticals

Using THELI pipeline in order to reduce Abell 226 multi-band optical images

In this paper we review THELI (Erben & Schrimer, 2005), an image processing pipeline developed to reduce multi-pointing optical images taken by mosaic CCD cameras. This pipeline works on raw images by removing several instrumental contaminations, implementing photometric calibration and astrometric alignment, and constructing a deep co-added mosaic image complemented by a weight map. We demonstrate the procedure of reducing NGC3923 images from raw data to the final results. We also demonstrate the quality of our data reduction strategy using mag-count and mag-error in mag plots. Emphasis is mainly placed on photometric calibration which is of great interest to us due to our scientific case. Based on the cross-association of the extracted catalogue against a reference catalogue of stellar magnitudes, zero-point calibration is performed. Our data reduction strategy and the method employed for cross-correlating large catalogues is also presented.Comment: 5 pages, 2 figure

A class of extremising sphere-valued maps with inherent maximal tori symmetries in SO(n)

In this paper we consider an energy functional depending on the norm of the gradient and seek to extremise it over an admissible class of Sobolev maps defined on an annulus and taking values on the unit sphere whilst satisfying suitable boundary conditions. We establish the existence of an infinite family of solutions with certain symmetries to the associated nonlinear Euler-Lagrange system in even dimensions and discuss the stability of such extremisers by way of examining the positivity of the second variation of the energy at these solutions

Teratogenic effects of gabapentin on the skeletal system of Balb/C mice fetuses

Objectives: To evaluate the effects of gabapentin )GBP( administration on mice fetuses. Methods: This study was carried out in Birjand University of Medical Sciences during 2008. Thirty Balb/c pregnant mice were divided randomly into 3 groups: 2 experimental groups that received 25 mg/kg )I( and 50 mg/kg )II( of GBP intraperitoneally for the first 15 days of pregnancy, and a control group that received normal saline. External observations of day 18 fetuses and skeleton double staining were performed. Results: Both experimental groups showed similar disorders that can be categorized as the following: 1( decrease of fetal body weight and increase of fetal resorption, 2( macroscopic malformations, and 3( skeletal malformations. Fetal body weights were significantly lower, and fetus resorptions were significantly higher in both treated groups compared to the control group. Macroscopic malformations included exencephaly, limbs defects, brachygnathia, vertebral column deformity, and fetuses with severe retarded growth. Skeletal malformations included delayed ossification, scoliosis, calvaria deformity, and mandibular hypoplasia. Conclusion: This study revealed that GBP can induce previously unreported severe malformations if it is used continuously during the implantation, neurulation, and organogenesis stages of pregnancy. Therefore, it is suggested that great caution should be exercised in using GBP during the early stages of pregnancy until further studies are performed to better understand these effects

Zandaqa in the early Abbasid period with special reference to the poetry

SIGLEAvailable from British Library Document Supply Centre- DSC:D65139/86 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Self-synchronization of Kerr-nonlinear Optical Parametric Oscillators

We introduce a new, reduced nonlinear oscillator model governing the spontaneous creation of sharp pulses in a damped, driven, cubic nonlinear Schroedinger equation. The reduced model embodies the fundamental connection between mode synchronization and spatiotemporal pulse formation. We identify attracting solutions corresponding to stable cavity solitons and Turing patterns. Viewed in the optical context, our results explain the recently reported $\pi$ and $\pi/2$ steps in the phase spectrum of microresonator-based optical frequency combs

Self-synchronization Phenomena in the Lugiato-Lefever Equation

The damped driven nonlinear Schr\"odinger equation (NLSE) has been used to understand a range of physical phenomena in diverse systems. Studying this equation in the context of optical hyper-parametric oscillators in anomalous-dispersion dissipative cavities, where NLSE is usually referred to as the Lugiato-Lefever equation (LLE), we are led to a new, reduced nonlinear oscillator model which uncovers the essence of the spontaneous creation of sharply peaked pulses in optical resonators. We identify attracting solutions for this model which correspond to stable cavity solitons and Turing patterns, and study their degree of stability. The reduced model embodies the fundamental connection between mode synchronization and spatiotemporal pattern formation, and represents a novel class of self-synchronization processes in which coupling between nonlinear oscillators is governed by energy and momentum conservation.Comment: This manuscript is published in Physical Review A. Copyright 2017 by the American Physical Society. arXiv admin note: text overlap with arXiv:1602.0852