61 research outputs found

    Indian summer monsoon precipitation climatology in a high-resolution regional climate model: Impacts of convective parameterization on systematic biases

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    In an attempt to develop a better simulation of the climatology of monsoon precipitation in climate models, this paper investigates the impacts of different convective closures on systematic biases of an Indian monsoon precipitation climatology in a high-resolution regional climate model. For this purpose, the Weather Research Forecast (WRF) model is run at 45- and 15-km (two-way nested) resolution with three convective parameterization schemes, namely the Grell-Devenyi (GD), the Betts-Miller-Janji (BMJ), and the Kain-Fritsch (KF), for the period 1 May-31 October 2001-07. The model is forced with the NCEP-NCAR reanalysis data as the initial and boundary conditions. The simulated June-September (JJAS) mean monsoon rainfall with the three convective schemes is compared with the observations. KF is found to have a high moist bias over the central and western coastal Indian region while GD shows the opposite. Among the three, BMJ is able to produce a reasonable mean monsoon pattern. In an attempt to get further insight into the seasonal bias and its evolution, the probability distribution function (PDF) of different rain-rate categories and their percentage contribution to the seasonal total are computed. BMJ and KF underestimate the observations for lighter rain rates and overestimate for rain-rate categories of more than 10 mm day -1. GD shows an overestimation for lighter rain and an underestimation of PDF for moderate categories. The seasonal patterns of evolution of PDF plots of three rain-rate categories are analyzed to determine whether the convective schemes show any systematic bias throughout the season or if they have problems during certain phases of the monsoon. This shows that the GD systematically overestimates the lighter rain rate and underestimates the moderate rain rate throughout the season, whereas BMJ and KF have problems in the initial stages. The heavy rain category is systematically overestimated by the KF compared to the other two. To further evaluate the proportionate contribution of each rain-rate bin to the total rain, the percentage contribution of each rain rate to the seasonal total is computed. Analyzing all the rain-rate simulations produced by the three schemes, it is found that KF has a moist bias and GD has a dry bias in the spatiotemporal distribution of the monsoon precipitation. Further, this paper investigates the causes behind the mean monsoon precipitation bias. It is shown that GD produces a model climate where the vertical velocity is less than that of the observations up to 500 hPa and the vertically integrated moist instability is also weaker. KF, on the other hand, shows a higher than the observed vertical velocity and a stronger moist instability. Along with this, the vertical profile of heating suggests a warmer middle level in the KF case and significantly reduced midlevel heating for GD. Thus, KF (GD) has produced a model atmosphere that has a stronger (weaker) convective instability to produce the observed bias in the model precipitation. BMJ is found to simulate a reasonable heating profile, along with the realistic moist instability and seasonal cycle of evaporation and condensation. Insight derived from the analysis is expected to help improve the convective parameterizations

    How aware are we regarding vector borne diseases? A community based study in a slum of Kolkata, India

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    Background: Vector borne diseases (VBDs) form a major part of the communicable diseases in India. Ignorance and impoverished conditions of people contribute in creating source and spread of vector borne diseases and hinder disease control strategy. Slums are more vulnerable to vector borne diseases because of poor environmental condition, standard of living, poverty and ignorance of the people. This study is a small endeavour to highlight the awareness of residents of slum area of Chetla, Kolkata, West Bengal, India regarding vector borne diseases. Objectives were to assess the awareness of the study population regarding different vector borne diseases and to find out the association of awareness with relevant demographic variables.Methods: A community based observational, cross-sectional study was conducted among adult population in a slum area of Chetla, Kolkata, West Bengal, India. Multivariate logistic analysis was done to find out association of awareness with relevant variables.Results: Awareness regarding malaria was good and that of dengue was satisfactory while awareness regarding other vector borne diseases was poor. Age, sex, caste, education and social class were found significantly associated with satisfactory awareness. Younger population i.e. age ≤35years, males, general caste people, literacy status above primary school and social class III and above had better awareness regarding vector borne diseases.Conclusions: This study uncovered the lacunae regarding awareness of the study population regarding vector borne diseases. It can be concluded that intensified efforts towards creating public awareness and mobilizing the community regarding the identified issues should be addressed

    Patients in a private hospital in India leave the emergency department against medical advice for financial reasons

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    BACKGROUND: Some reports indicate financial concerns as a factor affecting ED patients leaving the acute care setting against medical advice (AMA). In India, no person is supposed to be denied urgent care because of inability to pay. Since a large proportion of the Indian health care system is financed by out-of-pocket expenses, we investigate the role of financial constraints for ED patients at a private hospital in India in leaving AMA. METHODS: A prospective ED-based cross-sectional survey of patients leaving AMA was conducted at a private hospital in India from 1 October 2010 to 31 December 2010. Descriptive statistics and the chi-square test were used to identify associations between financial factors and the decision to leave the hospital AMA. RESULTS: Overall, 55 (3.84%) ED patients left AMA, of which 46 (84%) reported leaving because of financial restrictions. Thirty-nine (71%) respondents indicated the medical bill would represent more that 25% of their annual income. Females (19/19) were more likely to leave AMA for financial reasons compared to males (27/36, p = 0.017). Among females who signed out AMA, the decision was never made by the female herself. CONCLUSION: The number of people leaving the ED AMA in a private Indian hospital is relatively high, with most leaving for financial reasons. In most cases, women did not decide to leave the ED AMA for themselves, whereas males did. This survey suggests that steps are needed to ensure that the inability to pay does not prevent emergent care from being provided

    Growth Inhibition of Human Gynecologic and Colon Cancer Cells by Phyllanthus watsonii through Apoptosis Induction

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    Phyllanthus watsonii Airy Shaw is an endemic plant found in Peninsular Malaysia. Although there are numerous reports on the anti cancer properties of other Phyllanthus species, published information on the cytotoxicity of P. watsonii are very limited. The present study was carried out with bioassay-guided fractionation approach to evaluate the cytotoxicity and apoptosis induction capability of the P. watsonii extracts and fractions on human gynecologic (SKOV-3 and Ca Ski) and colon (HT-29) cancer cells. P. watsonii extracts exhibited strong cytotoxicity on all the cancer cells studied with IC50 values of ≤ 20.0 µg/mL. Hexane extract of P. watsonii was further subjected to bioassay-guided fractionation and yielded 10 fractions (PW-1→PW-10). PW-4→PW-8 portrayed stronger cytotoxic activity and was further subjected to bioassay-guided fractionation and resulted with 8 sub-fractions (PPWH-1→PPWH-8). PPWH-7 possessed greatest cytotoxicity (IC50 values ranged from 0.66 – 0.83 µg/mL) and was selective on the cancer cells studied. LC-MS/MS analysis of PPWH-7 revealed the presence of ellagic acid, geranic acid, glochidone, betulin, phyllanthin and sterol glucoside. Marked morphological changes, ladder-like appearance of DNA and increment in caspase-3 activity indicating apoptosis were clearly observed in both human gynecologic and colon cancer cells treated with P. watsonii especially with PPWH-7. The study also indicated that P. watsonii extracts arrested cell cycle at different growth phases in SKOV-3, Ca Ski and HT-29 cells. Cytotoxic and apoptotic potential of the endemic P. watsonii was investigated for the first time by bioassay-guided approach. These results demonstrated that P. watsonii selectively inhibits the growth of SKOV-3, Ca Ski and HT-29 cells through apoptosis induction and cell cycle modulation. Hence, P. watsonii has the potential to be further exploited for the discovery and development of new anti cancer drugs

    Lidar investigation of tropical nocturnal boundary layer aerosols and cloud macrophysics

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    Observational evidence of two-way association between nocturnal boundary layer aerosols and cloud macrophysical properties over a tropical urban site is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary layer aerosols and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary layer clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the aerosol mixing height associated with the nocturnal boundary layer. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship
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