Channel Estimation for MIMO MC-CDMA Systems

The concepts of MIMO MC-CDMA are not new but the new technologies to improve their functioning are an emerging area of research. In general, most mobile communication systems transmit bits of information in the radio space to the receiver. The radio channels in mobile radio systems are usually multipath fading channels, which cause inter-symbol interference (ISI) in the received signal. To remove ISI from the signal, there is a need of strong equalizer. In this thesis we have focused on simulating the MIMO MC-CDMA systems in MATLAB and designed the channel estimation for them

Self-organized metal nanostructures through laser driven thermocapillary convection

When ultrathin metal films are subjected to multiple cycles of rapid melting and resolidification by a ns pulsed laser, spatially correlated interfacial nanostructures can result from a competition among several possible thin film self-organizing processes. Here we investigate self-organization and the ensuing length scales when Co films (1-8 nm thick) on SiO_{\text{2}} surfaces are repeatedly and rapidly melted by non-uniform (interference) laser irradiation. Pattern evolution produces nanowires, which eventually break-up into nanoparticles exhibiting spatial order in the nearest neighbor spacing, \lambda_{NN2}.The scaling behavior is consistent with pattern formation by thermocapillary flow and a Rayleigh-like instability. For h_{0}\leq2 nm, a hydrodynamic instability of a spinodally unstable film leads to the formation of nanoparticles.Comment: 10 pages, 3 figure

Analytical Method Development and Validation of Assay and Dissolution for Nisoldipine ER Tablets by RP-HPLC.

The present study has been undertaken in order to develop a new, simple, reproducible validatable, transferable, robust, reliable, accurate and precise individual methodology for the Assay and Dissolution of Nisoldipine in pharmaceutical dosage forms by using HPLC(Reverse phase). An attempt was made in a stepwise manner to develop a simple, rapid, selective and sophisticated Assay method, by High performance liquid chromatography (Reverse phase) for the Nisoldipine. The following stepwise protocol was followed. As a start up, literature survey was done and from the literature survey chemical profile like solubility, chemical structure, pKa value and analytical profile were obtained. From the data obtained, UV spectroscopic study was tried in the first place. Later several trials were done in RP-HPLC using a different combination of mobile phases and finally optimized. After optimization of the HPLC method, validation of the analytical method for the developed RP-HPLC method was done in accordance with the ICH guidelines. An isocratic RP- HPLC method for analysis of Nisoldipine in pharmaceutical dosage form has been developed and validated. Best separation was achieved on a PEERLESS BASIC C18 (100 × 4.6 mm) 1.8μm column using a mobile phase composition of pH 6.8 buffer: Methanol: ACN (30:30:40) at a flow rate of 1.0 mL/min. UV detection was performed at 333 nm. The method was validated for specificity, linearity, precision, accuracy, robustness, ruggedness & solution stability according ICH guidelines. The calibration plot was linear over the concentration range 12.5-75ppm with correlation coefficient 0.9998. The accuracy was good. The HPLC method developed is accurate, precise, reproducible, specific, and stability indicating. The method is linear over a wide range, economical and utilizes a mobile phase which can be easily repared. All these factors make this method suitable for quantification of Nisoldipine in bulk drugs and in pharmaceutical dosage forms without interference. It can therefore be concluded that use of the method can save much time and money and it can be used even in small laboratories with very high accuracy and precision. An isocratic RP- HPLC method for analysis of Nisoldipine in pharmaceutical dosage form has been developed and validated. Best separation was achieved on a PRONTOSIL C18 H (100 × 4.6 mm) 3μm column using a mobile phase of composition of pH 3buffer: ACN: Methanol (30:40:30) at a flow rate of 1.5mL/min. UV detection was performed at 333 nm. The method was validated for specificity, linearity, precision, accuracy, robustness, ruggedness & solution stability according ICH guidelines. The calibration plot was linear over the concentration range 10-60ppm with correlation coefficient 0.9997. The accuracy was good. . The data validation shows that the RP-HPLC method is accurate, robust and possesses excellent linearity and precision characteristics. This method can be successfully used for the quantitation of Nisoldipine as active substance, in dissolution studies and in tablet dosage forms. So it can be concluded that the developed method can be easily applied for the routine quality control analysis of Nisoldipine drug and it’s Formulation

Study on clinical profile of Paediatric HIV infection in the age group of 18 months to 12 years and to correlate with CD4 count

INTRODUCTION: World over 38.6 million people are living with HIV, follow of which 2.3 million i.e. 5.9% are children <15 years of age. • In 2007 – 4,20,000 children were newly infected. • Estimated children living with HIV / AIDS in India is 0.17 – 0.24 million (3.5-5% of people with HIV). • Prevalence of HIV in pregnant mother is 0.6% - 0.7% (National). • Adult prevalence is 0.36% (0.43% males and 0.29% females). • Children account for 18% of total deaths due in AIDS i.e. 1 in every six AIDS death every year is a child, but they are < 1 in every twenty five persons getting treatment. AIM OF THE STUDY: 1. To study the clinical profile of pediatric HIV infection in the age group of 18 month to 12 years. 2. To correlate the clinical features with the CD4 count. MATERIALS AND METHODS: Nature of Study: Descriptive study. Study population: 100 children who were registered in ART centre over a period of 1 year were taken. Period and Place of study: This study was conducted over a period of 1 year from Oct 2007-Oct 2008 at Govt. Mohan Kumaramangalam Medical College Hospital, Salem. Inclusion Criteria: Children who got registered in ART centre in the age group of 18 months to 12 years, whose diagnosis in confirmed by Rapid antigen tests or ELISA were included. Exclusion Criteria: Children <18 months were not taken as the facility for making diagnosis by PCR was not available in our centre. SUMMARY: 100 children who were infected with HIV were taken as study group. Among them, Asymptomatic were 22%, Symptomatic were 78%, PEM observed in 76% cases and severe PEM was noticed (Grade III and IV and) in 22%. Among the symptomatic HIV infected children the clinical feature that were observed, Generalised lymphadenopathy – 46%. Lymphadenopathy alone observed in 10% with average CD4 count being 25%. Lymphadenopathy associated with other features of stage II to IV HIV infection like pneumonia, skin lesions, oral lesions, severe PEM constitute about 26% and the average CD4 count in this group being 12-18%. Generalised lymphadenopathy was the most common clinical manifestation in this study. • Skin lesions were observed in 29% of children. Pruritic papular eruption being the common finding observed in 14 children with average CD4 % is bet (24 – 35%). Other lesions like scabies (CD4 11%), Herpes (CD4 7 – 31%) molluscum (CD4 11%). Extensive impetigo (CD4 11%) were also observed. These lesions were associates with low CD4 count. • Among oral lesion that were observed oral candidiasis was found in 3% and associated with low CD4 count (8-10%). • Among opportunistic infections, tuberculosis was found to be the commonest infection which was 30% (This include all forms of TB). • Severe anemia (<8g%) was found in 16% which were predominantly in the children belong to stage III a stage IV illness, who were also associated with low CD4 count. • As for as Nutritional status in concerned, children in stage IV disease belong to Grade III & IV PEM and height being <85% of the expected, where us, majority of stage I disease children have Grade IPEM. • MTC transmission accounts for 97% and being the majority one. • Only one was delivered by emergency LSCS and the rest were delivered by normal vaginal delivery. For one child mode of delivery not known. • Only one child was replaced with milk substitute and given neviripine? perinatally. Rest of the children were given either Breast milk or mixed (both BF & Cow’s milk) not received Neviripine. • Since children infected with HIV having, Asymptomatic generalised lympadenopathy, skin lesions like eczema, pruritic papular eruptions, oral lesions like glossitis and gingivostomatitis were associated with the high CD4 count, intensifying the screening for HIV infection by high suspicion will help in diagnosing HIV infected children at the earliest, and thus they can be subjected to early management and follow up periodically. Early management include – chemoprophylaxis, immunization, management of opportunistic infection, nutritional support and ARV Therapy. • Proper ART to AN mother who were identified as HIV infected, ART to mother and baby during peripartum period, Elective LSCS, proper milk substitution will definitely found to be effective in reducing MTC transmission

Robust nanopatterning by laser-induced dewetting of metal nanofilms

We have observed nanopattern formation with robust and controllable spatial ordering by laser-induced dewetting in nanoscopic metal films. Pattern evolution in Co film of thickness 1\leq h\leq8 nm on SiO_{2} was achieved under multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the formation of cellular patterns which evolve into polygons that eventually break up into nanoparticles with monomodal size distribution and short range ordering in nearest-neighbour spacing R. Spatial ordering was attributed to a hydrodynamic thin film instability and resulted in a predictable variation of R and particle diameter D with h. The length scales R and D were found to be independent of the laser energy. These results suggest that spatially ordered metal nanoparticles can be robustly assembled by laser-induced dewetting

Maximizing the Number of Spatial Nulls with Minimum Sensors

In this paper, we attempt to unify two array processing frameworks viz, Acoustic Vector Sensor (AVS) and two level nested array to enhance the Degrees of Freedom (DoF) significantly beyond the limit that is attained by a Uniform Linear Hydrophone Array (ULA) with specified number of sensors. The major focus is to design a line array architecture which provides high resolution unambiguous bearing estimation with increased number of spatial nulls to mitigate the multiple interferences in a deep ocean scenario. AVS can provide more information about the propagating acoustic field intensity vector by simultaneously measuring the acoustic pressure along with tri-axial particle velocity components. In this work, we have developed Nested AVS array (NAVS) ocean data model to demonstrate the performance enhancement. Conventional and MVDR spatial filters are used as the response function to evaluate the performance of the proposed architecture. Simulation results show significant improvement in performance viz, increase of DoF, and localization of more number of acoustic sources and high resolution bearing estimation with reduced side lobe level

Cancellation of Towing Ship Interference in Passive SONAR in a Shallow Ocean Environment

Towed array sonars are preferred for detecting stealthy underwater targets that emit faint acoustic signals in the ocean, especially in shallow waters. However, the towing ship being near to the array behaves as a loud target, introducing additional interfering signals to the array, severely affecting the detection and classification of potential targets. Canceling this underlying interference signal is a challenging task and is investigated in this paper for a shallow ocean operational scenario where the problem is more critical due to the multipath phenomenon. A method exploiting the eigenvector analysis of spatio-temporal covariance matrix based on space time adaptive processing is proposed for suppressing tow ship interference and thus improving target detection. The developed algorithm learns the interference patterns in the presence of target signals to mitigate the interference across azimuth and to remove the spectral leakage of own-ship. The algorithm is statistically analyzed through a set of relevant metrics and is tested on simulated data that are equivalent to the data received by a towed linear array of acoustic sensors in a shallow ocean. The results indicate a reduction of 20-25dB in the tow ship interference power while the detection of long-range low SNR targets remain largely unaffected with minimal power-loss. In addition, it is demonstrated that the spectral leakage of tow ship, on multiple beams across the azimuth, due to multipath, is also alleviated leading to superior classification capabilities. The robustness of the proposed algorithm is validated by the open ocean experiment in the coastal shallow region of the Arabian Sea at Off-Kochi area of India, which produced results in close agreement with the simulations. A comparison of the simulation and experimental results with the existing PCI and ECA methods is also carried out, suggesting the proposed method is quite effective in suppressing the tow ship interference and is immensely beneficial for the detection and classification of long-range targets

Assessment of Farm Financial Literacy among Jasmine Growers in Tamilnadu, India

The unique nature of farm financial management calls for farmer to act as an entrepreneur. Being an farm entrepreneur the farmer should have enough financial literacy for effective financial management. Apart from training on production, post-harvest and marketing NAIP had given some information on farm financial management. A study was conducted to assess the financial literacy of jasmine farmers. Standardized knowledge test was employed to assess the financial literacy of farmers. For that, 100 farmers from Erode and 100 famers from Madurai district was surveyed. The collected data were analyzed using percentage analysis, multiple regression and factor analysis. It was concluded that, Erode farmers has high financial literacy than Madurai farmers. The results revealed that, age, education, experience, farm income, years of relationship with the bank, size of landholding, frequency of bank visit and bank account were significantly influenced the financial literacy of farmer. Key words: Financial literacy, NAIP, knowledge test and factor analysi