AREA AND POWER-EFFICIENT RECONFIGURABLE DIGITAL DOWN CONVERTER ON FPGA

This paper presents a field-programmable gate array (FPGA)-based digital down converter (DDC) that can reduce the bandwidth from about 70 MHz to 182.292 kHz. The proposed DDC consists of a polyphase COordinate Rotation DIgital Computer (CORDIC) processor and a multirate filter. The advantage of polyphase CORDIC processor is to process with high sample rate input data and produces computational efficient noiseless baseband spectrum. The pipeline multirate filter works at a high clock speed. Moreover, the multirate filter generates a fractional sample rate factor using a cubic B-spline Farrow filter. The proposed DDC is coded with optimal hardware description language (HDL) and tested on Kintex-7 Xilinx FPGA as the target device. Experimental results indicate that the proposed design saves chip area, power consumption and operates at high speed without loss of any functionality. Additionally, the proposed design offers sufficient spurious-free dynamic range (SFDR) and produces less than 1 Hz frequency resolution at the output

A study on the insertion characteristics of rectus muscles and its relation with the axial length of eye ball in cadaveric eyes from an eastern Indian population

The primary aim was to record measurements of relevant anatomy of recti muscle insertions in relation to limbus and with each other, and also to find whether these measurements vary with the axial length of the eyeball in an eastern Indian perspective. Eye balls ( n= 64, 20 female and 44 male) from Institutional eye bank were examined, within eight hours of death of the donor, under operating microscope by a single observer between May 2009 to April 2010.The mean distance from limbus to each rectus muscle at midpoint and at each end of insertion was measured by Castroviejo caliper. Additional parameters studied were length of each rectus muscle insertion (‘width’), distance between each rectus muscle insertion and measurement of axial length using 10 MHz ultrasonic A scan probe. Data collected was entered in Microsoft Office Excel 2007 and analysed by using statistical software SPSS 10. The frequency was calculated in percentages. Criteria for significance used in the study was at p<0.05. The mean age of the donors was 71years with a range of 26-86 years. Statistically significant difference (p<0.05) was found between male and female eyes regarding distance of limbus to midpoint point of only medial rectus muscle insertion. No statistically significant (p>0.05) difference was found between male and female eyes regarding length of line of rectus muscles insertion. No statistically significant correlation (p>0.05) was observed between the axial length and various measurements of rectus muscle insertion. Results of this study might help local strabismologists in revaluation of the spiral of Tilluax based on regional (Eastern Indian) perspective.Key words: Eye ball; Rectus muscles; Rectus muscle insertion; Axial length; Indian population

Aggregate dust model to study the polarization properties of comet C/1996 B2 Hyakutake

In our present study, the observed linear polarization data of comet Hyakutake are studied at wavelengths $\lambda=0.365\mu m$, $\lambda=0.485\mu m$ and 0.684$\mu m$ through simulations using Ballistic Particle-Cluster Aggregate and Ballistic Cluster-Cluster Aggregate aggregates of 128 spherical monomers. We first investigated that the size parameter of the monomer, $x$ $\sim$ 1.56 -- 1.70, turned out to be most suitable which provides the best fits to the observed dust scattering properties at three wavelengths $\lambda = 0.365$$\mu m$, 0.485$\mu m$ and 0.684$\mu m$. Thus the effective radius of the aggregate (r) lies in the range $0.45 \mu m \le r \le 0.49 \mu m$ at $\lambda = 0.365$$\mu m$; $0.60 \mu m \le r \le 0.66 \mu m$ at $\lambda = 0.485$$\mu m$ and $0.88 \mu m \le r \le 0.94 \mu m$ at $\lambda = 0.684$$\mu m$. Now using superposition \textsc{t-matrix} code and the power-law size distribution, $n(r) \sim r^{-3}$, the best-fitting values of complex refractive indices are calculated which can best fit the observed polarization data at the above three wavelengths. The best-fitting complex refractive indices $(n,k)$ are found to be (1.745, 0.095) at $\lambda = 0.365$ $\mu m$, (1.743, 0.100) at $\lambda = 0.485$ $\mu m$ and (1.695, 0.100) at $\lambda = 0.684$ $\mu m$. The refractive indices coming out from the present analysis correspond to mixture of both silicates and organics, which are in good agreement with the \textit{in situ} measurement of comets by different spacecraft.Comment: 9 pages, 3 figure

Harnessing Neem (Azadirachta indica A. Juss): A Sustainable Approach to Natural Farming

This review explores the rich concept of natural farming and the varied usage of neem in natural farming. Neem plant holds an important position in the rich tradition of India. The various portion of neem tree are used as insecticide, fertilizer, manure, soil conditioner etc. In recent era the major challenge is to increase the food production without harming the environment. Neem is considered ecofriendly, biodegradable, least persistence and also economic. Neem based formulations forms a considerable constituent of Natural farming. Successful results of application of neem based formulations in natural farming will provide adoption of cost effective technology to the farming community

Postequatorial horizontal rectus recession in the management of congenital nystagmus

Postequatorial (12 mm) recession of all four horizontal recti was done in nine patients with congenital nystagmus. Fifteen of 18 eyes showed decreased amplitude of nystagmus while 12 eyes also showed an increase in visual acuity. Functionally, significant limitation of ocular motility was not encountered despite unconventionally large recessions

An unusual case of late ocular changes after lightning injury.

We describe a case of late ocular changes after lightning injury. One year after the injury, complete ankyloblepharon, severe dry eye, corneal opacity, healed iritis and mature cataracts were noted in both eyes of the patient

Acute bilateral central serous chorioretinopathy following intra-articular injection of corticosteroid

There is increasing evidence in the literature implicating the use of exogenous steroids through various routes as a risk factor for the development of idiopathic central serous chorioretinopathy (ICSC). We report a case of acute bilateral ICSC following intra-articular injection of corticosteroids