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The weather systems that predominantly affect the eastern and northeastern parts of India during the pre-monsoon summer months (March, April and May) are severe thunderstorms, known as Nor'westers. The storms derive their names from the fact that they frequently strike cities and towns in the southern part of West Bengal in the afternoon from the north-west direction while traveling far from its place of genesis over the Bihar plateau. The storms are devastating in nature particularly due to strong (gusty) winds, heavy rains and hails associated with it. Although these storms are well known for its power of causing damages, studies on them are relatively few due to their small size and sparse network of observations. To address this important issue, the evolution of two Nor'westers of 12 March and 22 May 2003 over Kolkata is studied in detail in this paper using hourly Doppler weather radar (DWR) observations and high resolution Meteosat-5 imageries. In addition, supporting meteorological reports are used to find the large scale conditions that influence the moisture convergence and vertical wind shear. The genesis of both the storms is found to be over Bihar-Jharkhand region and beyond the range of the DWR. The satellite observations are found to be useful in identifying the location and initiation of the storms. The movements of the storms are captured by the DWR estimated vertical cross-section of reflectivities. The Doppler estimate shows that the 12 March storm had a vertical extent of about 10-12 km at the time of maturity and that of 22 May reaching up to 18 km signifying deep convection associated with these events. The genesis, maturity and dissipation are well brought out by the hourly DWR and satellite imageries. The DWR observations suggest that the systems move at a speed of 20-25m/s. The DWR estimated precipitation shows a detailed spatial distribution around Kolkata with several localized zones of heavy rain and this is found to be well supported by the nearby station observations. This study establishes that DWR observations along with hourly satellite imageries are able to capture the evolution of Nor'westers. The study also shows that the composite DWR-satellite information is a reliable tool for nowcasting the location, time and path of movement of Nor'westers. Based on these observations, a conceptual model of the Nor'wester is proposed. [ABSTRACT FROM AUTHOR]

Aims: The objective of the paper is to study the role of partogram in the outcome of spontaneous labour in primigravidae at term with singleton pregnancy and vertex as the presenting part. Methods: This prospective observational study was carried out in the labour room of the department of Gynaecology and Obstetrics of Medical College & Hospital, Kolkata, over a period of one year i.e. from June 2011 to May 2012 after obtaining approval from the institutional ethical committee. Analysis of the progress of labour was done in five hundred women with the help of modified WHO partograph. The study population was divided into three groups. Group I had a total observed duration of active stage six hours or less and their cervicograph remained on or to the left of the alert line. Group II had total observed duration of active phase between more than six hours and less than ten hours and their cervicograph remained between the alert and action line. Group III, who had the duration of observed active phase more than 10 hours, had their cervicograph crossing the action line. The different types of abnormal labor were studied. The maternal and fetal outcomes were assessed. Results: 80.8% of the women belonged to group I, 15.2% to group II and 4% to group III. Surgical interference increased as the labour curve moved to the right of the alert line. Use of partogram helped in overall reduction in the duration of labour. Timely intervention reduced the incidence of prolonged labour and its sequelae. 19.2% of the women showed abnormal labour. Severe complications were successfully averted. There were no cases of maternal death, puerperal sepsis, ruptured uterus or fresh still births. Overall neonatal mortality rate was also reduced. Conclusions: The use of modified WHO partograph significantly improves the outcome of labour in both maternal & neonatal perspective. The WHO partograph should be used in all maternity units with incorporated management guidelines. [ABSTRACT FROM AUTHOR]