Stability of vertical coherence of ambient noise in shallow waters off the Indian coast

140-143<span style="font-size:9.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-US">Ambient noise field in shallow waters is very complicated due to wave guide nature of the environment and multiple reflections between the sea surface and the sea bottom. Vertical coherence for high sea state is estimated for different coastal sites with dissimilar sound speed profiles, and the effect of wind forcings on coherence pattern is addressed here. Time averaged coherence for wind generated noise is a relatively stable feature and is independent of the temporal variations in the ocean environment.  This has been demonstrated using estimates spread over a period of time for wind forcings above 4 beau fort. Coherence for sandy site (off Cuddalore) with reflective seabed is mostly positive, due to noise field that is fairly symmetric around the horizontal whereas for silty site (off Cochin), the absorbing seabed gives rise to an asymmetric field. Off Vizag, the upward refracting sound speed profile that leads to a surface duct makes coherence more symmetric than the other sites.</span

Application of wavelets for analysing ship noise from shallow water ambient noise measurements

11-16Time series measurements of shallow water ambient noise have been made for a week, off Tuticorin by deploying an autonomous ambient noise measurement system. Preliminary analysis of measurements showed that predominantly the noise field is due to ship crossing other than the wind noise. This paper presents the work carried out in extraction of specific ship noise sources by application of wavelet transforms as wavelet denoising algorithm has finer decomposition and reconstruction properties in the frequency domain. Frequency localization of wavelet denoising technique is used to efficiently localize the ship noise. Methodology involves study of spectrogram of the noise measurements initially and then application of wavelet decomposition (down sampling). Optimal threshold value for the wavelet coefficients is calculated and this yields 2(2n-1) levels to denoise the signal. From the wavelet coefficients, reconstruction (up sampling) of the decomposed signal is performed. Finally the spectrogram of the reconstructed signal is studied. Results show clearly the narrow band frequency components of shipping noise present. This has applications in finding different types of boats/ship noise and the technique is applied to different data sets for finding such sources

A new species of the genus Tonoscolex Gates, 1933 (Clitellata: Megascolecidae) from India

Ahmed, Shakoor, Emiliyamma, K. G., Marimuthu, Nithyanandam, Sajan, Sheikh, Julka, J. M. (2022): A new species of the genus Tonoscolex Gates, 1933 (Clitellata: Megascolecidae) from India. Zootaxa 5124 (3): 375-382, DOI: https://doi.org/10.11646/zootaxa.5124.3.

Evidence for lower CD4 + T cell and higher viral load in asymptomatic HIV-1 infected individuals of India: Implications for therapy initiation

Purpose: We have earlier documented that the south Indian population had lower CD4 counts. The aim of this study was to investigate a previous suggestion on a new CD4+ T cell cut off and association with HIV-1 RNA levels for decision on anti retroviral therapy in India (south). Methods: We evaluated a new methodology i.e., artus real-time PCR and CD4+ T cell count by Guava EasyCD4™ system. From 146 HIV infected individuals seen at a tertiary care centre, blood was collected for CD4+ T cell and HIV-1 RNA estimation. Results: The receiver operating characteristic curve cut off value for the CD4 counts to distinguish between CDC clinical categories A and B was 243 cells/μL, and to distinguish B and C was 153 cells/μL. The RNA level that differentiated CDC A and B was 327473 RNA copies/mL, while for CDC B and C was 688543 copies/mL. There was a significant negative correlation (r = -0.55, P < 0.01) between the RNA estimated and CD4+ T cell counts in HIV infected individuals. Conclusions: A majority with CD4 counts of 201-350 cells/μL in our population had higher viral load than the treatment threshold suggested by the International AIDS society and the above two methodologies are useful in monitoring HIV infections

Comparison of Microcapillary Cytometry Technology and Flow Cytometry for CD4(+) and CD8(+) T-Cell Estimation

An alternative technology for the estimation of T cells based on a microcapillary technique (Guava Technologies, Hayward, CA) was compared to FACSCount (Becton Dickinson, San Jose, CA). Samples from 51 human immunodeficiency virus-infected and 21 healthy individuals were tested. The correlation (r) of the two systems for CD4(+) T cells was 0.994, and the coefficient of variation was 6.5%, establishing equable performance between the two technologies