Cochin University of Science and Technology

About: Cochin University of Science and Technology is a education organization based out in Kochi, Kerala, India. It is known for research contribution in the topics: Thin film & Natural rubber. The organization has 5382 authors who have published 7690 publications receiving 103827 citations. The organization is also known as: CUSAT & Cochin University.

A difference boosting neural network for automated star-galaxy classification

Abstract: In this paper we describe the use of a new articial neural network, called the dierence boosting neural network (DBNN), for automated classication problems in astronomical data analysis. We illustrate the capabilities of the network by applying it to star galaxy classication using recently released, deep imaging data. We have compared our results with classication made by the widely used Source Extractor (SExtractor) package. We show that while the performance of the DBNN in star-galaxy classication is comparable to that of SExtractor, it has the advantage of signicantly higher speed and flexibility during training as well as classication.

Initial results from SKiYMET meteor radar at Thumba (8.5°N, 77°E): 1. Comparison of wind measurements with MF spaced antenna radar system

Abstract: [1] In the present communication, initial results from the allSKy interferometric METeor (SKiYMET) radar installed at Thumba (8.5°N, 77°E) are presented. The meteor radar system provides hourly zonal and meridional winds in the mesosphere lower thermosphere (MLT) region. The meteor radar measured zonal and meridional winds are compared with nearby MF radar at Tirunalveli (8.7°N, 77.8°E). The present study provided an opportunity to compare the winds measured by the two different techniques, namely, interferometry and spaced antenna drift methods. Simultaneous wind measurements for a total number of 273 days during September 2004 to May 2005 are compared. The comparison showed a very good agreement between these two techniques in the height region 82–90 km and poor agreement above this height region. In general, the zonal winds compare very well as compared to the meridional winds. The observed discrepancies in the wind comparison above 90 km are discussed in the light of existing limitations of both the radars. The detailed analysis revealed the consistency of the measured winds by both the techniques. However, the discrepancies are observed at higher altitudes and are attributed to the contamination of MF radar neutral wind measurements with Equatorial Electro Jet (EEJ) induced inospheric drifts rather than the limitations of the spaced antenna technique. The comparison of diurnal variation of zonal winds above 90 km measured by both the radars is in reasonably good agreement in the absence of EEJ (during local nighttime). It is also been noted that the difference in the zonal wind measurements by both the radars is directly related to the strength of EEJ, which is a noteworthy result from the present study.

Bioaccumulation and depuration of some trace metals in the mussel, Perna viridis (Linnaeus).

Abstract: Bivalves are well known for their ability to concentrate heavy metals in their tissue from environmental water. Experimental studies on the accumulation of these pollutants by molluscs have been extensively conducted. The depuration of accumulated metals in a toxicant free medium has also been studied. Bivalve molluscs may form useful tools in monitoring heavy metal pollution. However, such studies are scant in tropical species. This paper reports the bioaccumulation and depuration of Hg, Cu, Zn and Pb by the mussel Perna viridis (Linnaeus) from seawater and explores its suitability as an indicator organism for metal pollution.

Sleep quality and nocturnal hypoxaemia and hypercapnia in children and young adults with cystic fibrosis

Abstract: Objectives The aim of the study was to evaluate sleep quality and nocturnal gas exchange in patients with cystic fibrosis (CF) and to assess if sleep quality and daytime lung function could predict nocturnal hypoxaemia or hypercapnia. Study design Daytime sleepiness and objective sleep quality were evaluated by the Pittsburgh Sleep Quality Index (PSQI) and actigraphy in 25 children and 55 young adults (mean age 24±10 years, forced expiratory volume in 1 s (FEV 1 ) 41±11% predicted). Nocturnal gas exchange was assessed by pulse oximetry (SpO 2 ) and transcutaneous carbon dioxide (PtcCO 2 ) recordings. Eleven patients underwent simultaneous polysomnography (PSG). Results PSQI was 6.3±3.4 with 51% of the patients having a score >5 corresponding to significant sleep complaints. On actigraphy, sleep efficiency was impaired at 79±11% with a fragmentation index at 41±18. Mean nocturnal SpO 2 was 93±3% with 18% of the patients exhibiting >10% of night time spent with a value below 90%. Mean PtcCO 2 was 44±6 mm Hg with 47% of the patients exhibiting >10% of night time with a value >45 mm Hg. Daytime arterial blood gases correlated with nocturnal gas exchange. FEV 1 was the only lung function parameter that correlated with nocturnal SpO 2 (p 2 and PtcCO 2 accurately identified rapid eye movement sleep hypoventilation. Conclusions Patients with CF exhibit poor sleep quality that does not predict nocturnal gas exchange. Nocturnal hypoxaemia and hypercapnia can be identified by simple tools.

Formation of anoxia and denitrification in the bottom waters of a tropical estuary, southwest coast of India

Abstract: . Hydrographic characteristics of the southwest coast of India and its adjoining Cochin backwaters (CBW) were studied during the summer monsoon period. Anomalous formation of anoxia and denitrification were observed in the bottom layers of CBW, which have not been previously reported elsewhere in any tropical estuarine systems. The prevalent upwelling in the Arabian Sea (AS) brought cool, high saline, oxygen deficient and nutrient-rich waters towards the coastal zone and bottom layers of CBW during the high tide. High freshwater discharge in the surface layers brought high amount of nutrients and makes the CBW system highly productive. Intrusion of AS waters seems to be stronger towards the upstream end (~15 km), than had been previously reported, as a consequence of the lowering of river discharges and deepening of channels in the estuary. Time series measurements in the lower reaches of CBW indicated a low mixing zone with increased stratification, 3 h after the high tide (highest high tide) and high variation in vertical mixing during the spring and neap phases. The upwelled waters (O2≤40 μM) intruded into the estuary was found to lose more oxygen during the neap phase (suboxic O2≤4 μM) than spring phase (hypoxic O2≤10 μM). Increased stratification coupled with low ventilation and presence of high organic matter have resulted in an anoxic condition (O2=0), 2–6 km away from barmouth of the estuary and leads to the formation of hydrogen sulphide. The reduction of nitrate and formation of nitrite within the oxygen deficient waters indicated strong denitrification intensity in the estuary. The expansion of oxygen deficient zone, denitrification and formation of hydrogen sulphide may lead to a destruction of biodiversity and an increase of green house gas emissions from this region.