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

A comparative study of low dose magnesium sulphate therapy with Pritchard’s regime in management of Eclampsia

Background: Eclampsia is one of the most common causes of maternal and perinatal mortality and morbidity in India. Amongst the principles of management of eclampsia, the first is the control of convulsions. Magnesium sulphate is the main stay of treatment in eclampsia and imminent eclampsia. Average weight of Indian women is less than the western women due to which lower dose of magnesium sulphate can be used.  The aim of the study was to compare the efficacy of low dose magnesium sulphate regimen with standard Pritchard regimen in control of eclampsia.Methods: The study was carried out at emergency labour room, GMERS Sola Civil Hospital Ahmedabad. 120 patients of eclampsia were divided randomly into study group (n=60) receiving low dose MgSO4 and control group (n=60) receiving Pritchard regimen. The recurrence of convulsion, toxicity of MgSO4 and maternal and fetal outcome was studied.Results: It was observed that with low dose MgSO4 regime, convulsions were controlled in 91.7% of the cases. With standard Pritchard’s regime convulsions were controlled in 95% of patients. The maternal and perinatal mortality and morbidity were comparable in both groups.Conclusions: Low dose magnesium sulphate therapy is as effective as Pritchard’s regime for controlling convulsions in eclampsia and can be safely given in Indian women.

The Glove-like Structure of the Conserved Membrane Protein TatC Provides Insight into Signal Sequence Recognition in Twin-Arginine Translocation

In bacteria, two signal-sequence-dependent secretion pathways translocate proteins across the cytoplasmic membrane. Although the mechanism of the ubiquitous general secretory pathway is becoming well understood, that of the twin-arginine translocation pathway, responsible for translocation of folded proteins across the bilayer, is more mysterious. TatC, the largest and most conserved of three integral membrane components, provides the initial binding site of the signal sequence prior to pore assembly. Here, we present two crystal structures of TatC from the thermophilic bacteria Aquifex aeolicus at 4.0 Å and 6.8 Å resolution. The membrane architecture of TatC includes a glove-shaped structure with a lipid-exposed pocket predicted by molecular dynamics to distort the membrane. Correlating the biochemical literature to these results suggests that the signal sequence binds in this pocket, leading to structural changes that facilitate higher order assemblies

Ethylene-propylene Diene Rubber as a Futuristic Elastomer for Insulation of Solid Rocket Motors

The study carried out so far on the application of ethylene-propylene diene rubber (EPDM)in the field of insulation of case bonded solid rocket motors has been reviewed. The variousstudies by the authors (unpublished work) have also been reported. All these findings bring outthe excellent potential of EPDM as insulator in view of its ageing resistance, low-temperatureflexibility, low erosion rate, and low specific gravity

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

Diversity of Flowering Responses in Wild Arabidopsis thaliana Strains

Although multiple environmental cues regulate the transition to flowering in Arabidopsis thaliana, previous studies have suggested that wild A. thaliana accessions fall primarily into two classes, distinguished by their requirement for vernalization (extended winter-like temperatures), which enables rapid flowering under long days. Much of the difference in vernalization response is apparently due to variation at two epistatically acting loci, FRI and FLC. We present the response of over 150 wild accessions to three different environmental variables. In long days, FLC is among those genes whose expression is most highly correlated with flowering. In short days, FRI and FLC are less important, although their contribution is still significant. In addition, there is considerable variation not only in vernalization response, but also in the response to differences in day length or ambient growth temperature. The identification of accessions that flower relatively early or late in specific environments suggests that many of the flowering-time pathways identified by mutagenesis, such as those that respond to day length, contribute to flowering-time variation in the wild. In contrast to differences in vernalization requirement, which are mainly mediated by FRI and FLC, it seems that variation in these other pathways is due to allelic effects at several different loci

Social Determinants of Health and Distance Learning in Italy in the Era of the SARS-CoV-2 Pandemic

Objectives: To investigate the experiences by distance learning (DL) method during the first wave of the SARS-CoV-2 pandemic in Italy, and to search for correlations with purported experiences and respective levels of social determinants of health (SDH). Study design and methods: Cross-sectional online survey, investigating various SDH and parents’ attitude towards DL, proposed 6 months after the beginning of the pandemic to a sample population of parents with school-aged children throughout Italy. Results: A total of 3791 questionnaires were analyzed. Non-Italian parents complained more frequently of difficulties in providing support to their children in DL due to poor digital skills (p = 0.01), lack of good-quality digital equipment (p = 0.01), problems with the Italian language (p < 0.001), and a lower level of education (p < 0.001). When parents lived apart, greater difficulties in concentration in children using DL (p = 0.05) and a lower parental capacity to support DL (p = 0.002) were reported. Adequate digital structures appeared related to living in owned compared to rented property, higher levels of parental education, and better familial financial situations. Conclusions: Students from families with financial difficulties and low levels of parental education, or even those living in houses for rent or having separated parents, may be disadvantaged in an educational context since the introduction of DL

CURRENT STATUS OF AMBEWELA RESERVOIR OF SRI LANKA WITH SPECIALREFERENCE TO WATER POLLUTION

The water pollution trends in the Ambewela reservoir at the uppermost catchment of Kotmale River was assessed through a study on chemical and bio monitoring programme that carried out from March to October 2008.The mean average value (mean ± SD) of the nitrate, nitrite, phosphate and ammonia concentrations in Ambewela reservoir were 0.780 ± 1.386 mg/l, 0.103 ± 0.223mg/l, 0.051 ± 0.061mg/l and 0.218± 0.261 mg/l whereas values for the streams selected from Dambagasthalawa Oya were 0.985 ± 0.902 mg/l, 0.099  ± 0.207mg/l, 0.038 ± 0.026 mg/l and 0.085± 0.077 mg/l respectively. Average Chlorophyll- a values of the reservoir were 17.85 ± 17.858 mg/m3 and 8.30 ± 4.686 mg/m3for other two streams accordingly. Average BOD values of the reservoir were 8.06 ± 3.494 and 4.25 ± 2.251 for other two streams correspondingly.The bio monitoring studies also clearly showed sudden records of huge colonies of  Hydra(approximately 258/cm3) in the reservoir from time to time. This phenomenon was found in relatively dry period that directly coincided with intensified use of agro chemicals. Moreover, steady population of Chironomid (average population density 208/cm3) that is commonly accepted pollution indicator was reported at Ambewela reservoir throughout the study period.Therefore, both chemical and bio monitoring studies indicate eutrophic condition in Ambewela reservoir in which long run might affect on the ecology of the entire ecosystem. Hence prompt mitigatory action should be implemented to avoid further depletion.Key Words: Ambewela Reservoir, Water Pollution, Physico-Chemical Parameters, Chlorophyll –