Construction of fuzzy membership functions for urban vehicular exhaust emissions modeling

This paper presents a method for constructing a membership function (MF) for the fuzzy sets that expert systems deal with. This paper introduces a Bezier curve-based mechanism for constructing MFs of convex normal fuzzy sets. The mechanism can fit any given data set with a minimum level of discrepancy. In the absence of data, the mechanism can be intuitively manipulated by the user to construct MFs with the desired shape. MFs have been developed using the proposed mechanism for urban vehicular exhaust emission modeling. It has been observed that all meteorological and vehicular parameters have either S-shaped MFs or Z-shaped MFs. Gaussian MF has been mostly applied for modeling air quality. The present study explored the application of fuzzy MF to analyze air pollution data from vehicular emission. The study reveals that S-shaped and Z-shaped MF can be used in addition to Gaussian MF.

Placental histomorphology in unexplained foetal loss with thrombophilia

BACKGROUND & OBJECTIVES

Acquired and genetic thrombotic conditions, both organ and non organ specific, are associated with increased foetal wastage. This study was carried out to examine the placenta from women with abnormal pregnancies and a history of unexplained foetal loss, and to associate with maternal thrombophilia status.

METHODS

Placentas from eight women with history of unexplained foetal loss were analyzed for histopathological characteristics. All the women were simultaneously screened for the common acquired and genetic thrombophilia markers i.e., lupus anticoagulants ( LA), IgG / IgM antibodies for anticardiolipin (ACA), beta2 glycoprotein 1 (beta2GPI) and annexin V, protein C (PC), protein S (PS), antithrombin III (AT III), factor V Leiden ( FVL) mutation, prothrombin (PT) gene G20210A, methylene tetrahydrofolate reductase (MTHFR) C 677T, endothelial protein C receptor (EPCR) 23 bp insertion and plasminogen activator inhibitor ( PAI-1 4G/5G) polymorphisms

RESULTS

Six of eight women were positive for one or more thrombophilia markers. The placenta in all the cases except one, showed the characteristic features of infarct fibrin deposition and calcification. Among two women who were negative for thrombophilia, one showed clear evidence of thrombus in the placental sections while the other did not show any characteristic infarcts in the placental sections.

INTERPRETATION & CONCLUSION

Our findings showed that the histopathological examination of the placentas confirmed thrombophilia as the aetiological cause of thrombosis in 6 of the 8 women. The presence of thrombus in a negative thrombophilia woman suggests yet unidentified thrombophilia markers or probably non-haemostatic factors causing thrombosis.

Indoor air quality assessment in and around urban slums of Delhi city, India

The present study aims at investigating the indoor air quality (IAQ) in selected households in one of the urban slums i.e. the Nizamuddin slums in Delhi, the capital city of India. The study includes investigations and assessments on associated health effects on the occupants living in inefficiently designed houses having poor ventilation. The monitoring of indoor air pollutants e.g. the respirable suspended particulate matter (RSPM), the carbon dioxide (CO2), the carbon monoxide (CO), the sulphur dioxide (SO2) and the nitrogen dioxide (NO2) for all three seasons i.e. summer (April-June 2004), rainy (July-September 2004) and winter (December 2004-February 2005) have been conducted. In addition, the spirometry tests on the occupants, particularly the womenfolk and children have been performed to determine the incidence of acute respiratory infections (ARI). Questionnaire survey has also been conducted in the households during the study period to investigate the sick building syndrome (SBS). The study reveals maximum concentration of indoor air pollutants in households during winters (December 2004-February 2005) associated with aggravated respiratory problems like cough, phlegm, wheezing, and breathlessness among occupants particularly the women occupants. Besides, decrement in lung function indices (i.e. FVC and/or FEV1) due to increased concentrations of RSPM and CO2 indoors during winter period has also been observed in the women respondents. The study concludes that women and children indoors are most vulnerable to respiratory problems compared to other sexes. A high SBS score is observed in these 'urban poor' households because of inadequate ventilation.

PRACTICAL IMPLICATIONS

'High indoor airborne pollutants during winter are associated with respiratory problems for women and children in houses in urban slum in Delhi. The work demonstrated the need of further studies of indoor air quality for the 'urban poor' in developing countries.'

Indoor air quality assessment in and around urban slums of Delhi city, India

The present study aims at investigating the indoor air quality (IAQ) in selected households in one of the urban slums i.e. the Nizamuddin slums in Delhi, the capital city of India. The study includes investigations and assessments on associated health effects on the occupants living in inefficiently designed houses having poor ventilation. The monitoring of indoor air pollutants e.g. the respirable suspended particulate matter (RSPM), the carbon dioxide (CO2), the carbon monoxide (CO), the sulphur dioxide (SO2) and the nitrogen dioxide (NO2) for all three seasons i.e. summer (April-June 2004), rainy (July-September 2004) and winter (December 2004-February 2005) have been conducted. In addition, the spirometry tests on the occupants, particularly the womenfolk and children have been performed to determine the incidence of acute respiratory infections (ARI). Questionnaire survey has also been conducted in the households during the study period to investigate the sick building syndrome (SBS). The study reveals maximum concentration of indoor air pollutants in households during winters (December 2004-February 2005) associated with aggravated respiratory problems like cough, phlegm, wheezing, and breathlessness among occupants particularly the women occupants. Besides, decrement in lung function indices (i.e. FVC and/or FEV1) due to increased concentrations of RSPM and CO2 indoors during winter period has also been observed in the women respondents. The study concludes that women and children indoors are most vulnerable to respiratory problems compared to other sexes. A high SBS score is observed in these 'urban poor' households because of inadequate ventilation.

PRACTICAL IMPLICATIONS

'High indoor airborne pollutants during winter are associated with respiratory problems for women and children in houses in urban slum in Delhi. The work demonstrated the need of further studies of indoor air quality for the 'urban poor' in developing countries.'

Artificial neural network based carbon monoxide persistence models for episodic urban air quality management

This paper describes the development of artificial neural network (ANN) based carbon monoxide (CO) persistence (ANNCOP) models to forecast 8-h average CO concentration using 1-h maximum predicted CO data for the critical (winter) period (November-March). The models have been developed for three 8-h groupings of 10 P.M. to 6 A.M., 6 A.M., to 2 P.M. and 2-10 P.M., at two air quality control regions (AQCRs) in Delhi city, representing an urban intersection and an arterial road consisting heterogeneous traffic flows. The result indicates that time grouping of 2-10 PM is dominantly affected by inversion conditions and peak traffic flow. The ANNCOP model corresponding to this grouping predicts the 8-h average CO concentrations within the accuracy range of 68-71%. The CO persistence values derived from ANNCOP model are comparable with the persistence values as suggested by the Environmental Protection Agency (EPA), USA. This work demonstrates that ANN based model is capable of describing winter period CO persistence phenomena.

Urban air quality in mega cities: a case study of Delhi City using vulnerability analysis

Air pollution is one of the major environmental problems in India, affecting health of thousands of 'urban' residents residing in mega cities. The need of the day is to evolve an 'effective' and 'efficient' air quality management plan (AQMP) encompassing the essential 'key players' and 'stakeholders.' This paper describes the formulation of an AQMP for mega cities like Delhi in India taking into account the aforementioned key 'inputs.' The AQMP formulation methodology is based on past studies of Longhurst et al., (Atmospheric Environment, 30, 3975-3985, 1996); Longhurst & Elsom, ((1997). Air Pollution-II, Vol. 2 (pp. 525-532)) and Beatti et al., (Atmospheric Environment, 35, 1479-1490, 2001). Further, the vulnerability analysis (VA) has been carried out to evaluate the stresses due to air pollution in the study area. The VA has given the vulnerability index (VI) of 'medium to high' and 'low' at urban roadways/intersections and residential areas, respectively.

Suspended particulate matter distribution in rural-industrial Satna and in urban-industrial South Delhi

An air quality sampling program was designed and implemented to collect the baseline concentrations of respirable suspended particulates (RSP = PM10), non-respirable suspended particulates (NRSP) and fine suspended particulates (FSP = PM2.5). Over a three-week period, a 24-h average concentrations were calculated from the samples collected at an industrial site in Southern Delhi and compared to datasets collected in Satna by Envirotech Limited, Okhla, Delhi in order to establish the characteristic difference in emission patterns. PM2.5, PM10, and total suspended particulates (TSP) concentrations at Satna were 20.5 +/- 6.0, 102.1 +/- 41.1, and 387.6 +/- 222.4 microg m(-3) and at Delhi were 126.7 +/- 28.6, 268.6 +/- 39.1, and 687.7 +/- 117.4 microg m(-3). Values at Delhi were well above the standard limit for 24-h PM2.5 United States National Ambient Air Quality Standards (USNAAQS; 65 microg m(-3)), while values at Satna were under the standard limit. Results were compared with various worldwide studies. These comparisons suggest an immediate need for the promulgation of new PM2.5 standards. The position of PM10 in Delhi is drastic and needs an immediate attention. PM10 levels at Delhi were also well above the standard limit for 24-h PM10 National Ambient Air Quality Standards (NAAQS; 150 microg m(-3)), while levels at Satna remained under the standard limit. PM2.5/PM10 values were also calculated to determine PM2.5 contribution. At Satna, PM2.5 contribution to PM10 was only 20% compared to 47% in Delhi. TSP values at Delhi were well above, while TSP values at Satna were under, the standard limit for 24-h TSP NAAQS (500 microg m(-3)). At Satna, the PM10 contribution to TSP was only 26% compared to 39% in Delhi. The correlation between PM10, PM2.5, and TSP were also calculated in order to gain an insight to their sources. Both in Satna and in Delhi, none of the sources was dominant a varied pattern of emissions was obtained, showing the presence of heterogeneous emission density and that nonrespirable suspended particulate (NRSP) formed the greatest part of the particulate load.

Compensating for provider nonresponse using response propensities to form adjustment cells: the National Immunization Survey

OBJECTIVES

The National Immunization Survey (NIS) uses two phases of data collection to obtain vaccination information from a sample of young children: a random-digit-dialing (RDD) survey for identifying households with children 19-35 months of age, followed by a mail survey for obtaining provider-reported vaccination histories about these children. Provider-reported vaccination histories are used to estimate vaccination coverage rates. In 1998, provider-reported vaccination histories were not obtained for 32.9% of children with a completed RDD interview. This report describes the statistical methods adopted in 1998 to reduce the bias in vaccination coverage estimates that could result from "vaccination history nonresponse," that is, differences between children for whom provider data was obtained and those for whom it was not obtained.

METHODS

In the methods adopted in 1998, children with completed NIS RDD interviews are grouped into adjustment cells defined by their propensity to have adequate provider data. Sampling weights of children with adequate provider data are divided by the cell-specific weighted response rate to allow these children to represent all children in the cell.

RESULTS

Using an "optimal" number of cells, the overall extent of bias reduction was 0.5%, suggesting that provider nonresponse bias was small. Authoritative literature suggests using five cells. No statistically significant differences were observed in vaccination coverage estimates when comparing estimates based on the "optimal" number of cells with five cells. Thus, five adjustment cells are used to reduce provider nonresponse bias in the NIS vaccination coverage estimates. No substantively important differences were observed between estimates based on the methodology used prior to 1998 and the methodology adopted in 1998.

The role of ultrasound in the expectant management of early pregnancy loss

OBJECTIVE

To define the sonographic criteria which best determine the likelihood of successful expectant management of early pregnancy failure (EPF).

METHODS

Women with an ultrasound diagnosis of EPF at 7-14 weeks' gestation were offered the option of expectant management or surgical evacuation.

RESULTS

Five hundred and forty-five women had a diagnosis of EPF; 298 with incomplete miscarriage and 247 with missed miscarriage or an embryonic pregnancy. A total of 305 women opted for expectant management, with an overall success rate of 86%. The success rate for incomplete miscarriage (96%) was significantly better than that for missed miscarriage (62%).

CONCLUSION

This study demonstrates that EPF can be safely managed expectantly. Ultrasound has an invaluable role in predicting the likelihood of successful expectant management enabling patients to make an informed choice about their medical care.

Overview of the sampling design and statistical methods used in the National Immunization Survey

Abstract: The National Immunization Survey (NIS) is a large federally funded survey designed to estimate vaccination coverage rates for children residing in the United States aged 19 to 35 months. In 1999, over 8 million telephone call attempts were made to obtain provider-reported vaccination histories on 22,521 children in the age range of interest.

Food intake patterns and gallbladder disease in Mexican Americans

OBJECTIVE

Results of previous studies on diet and gallbladder disease (GBD), defined as having gallstones or having had surgery for gallstones, have been inconsistent. This research examined patterns of food intake in Mexican Americans and their associations with GBD.

DESIGN

Cross-sectional.

SUBJECTS

The study population included 4641 Mexican Americans aged 20-74 years who participated in the 1988-94 third National Health and Nutrition Examination Survey (NHANES III). GBD was diagnosed by ultrasound. Food intake patterns were identified by principal components analysis based on food frequency questionnaire responses. Component scores representing the level of intake of each pattern were categorized into quartiles, and prevalence odds ratios (POR) were estimated relative to the lowest quartile along with 95% confidence intervals (CI).

RESULTS

There were four distinct patterns in women (vegetable, high calorie, traditional, fruit) and three in men (vegetable, high calorie, traditional). After age adjustment, none were associated with GBD in women. However, men in the third (POR = 0.42, 95%CI 0.21-0.85) and fourth (POR = 0.53, 95%CI 0.28-1.01) quartiles of the traditional intake pattern were half as likely to have GBD as those in the lowest quartile.

CONCLUSIONS

These findings add to a growing literature suggesting dietary intake patterns can provide potentially useful and relevant information on diet-disease associations. Nevertheless, methods to do so require further development and validation.

Country of birth and prevalence of gallbladder disease in Mexican Americans

OBJECTIVES

This research sought to describe the association between country of birth and gallbladder disease (GBD) in Mexican Americans, identify subgroups at especially high risk, and identify risk factors that may mediate a birthplace-GBD association.

DESIGN

Cross-sectional.

METHODS

Our study population included 4157 Mexican Americans aged 20-74 who participated in the 1988-94 third National Health and Nutrition Examination Survey. GBD was diagnosed by ultrasound. Information on country of birth, education, income, and selected GBD risk factors was obtained from interviews. Prevalence odds ratios (POR) for GBD in Mexico- vs. US-born Mexican Americans were estimated by unconditional logistic regression, along with 95% confidence intervals (CI). To evaluate the extent to which GBD risk factors mediated the birthplace-GBD association, PORs for country of birth were compared in models with and without additional covariates.

RESULTS

Age-adjusted GBD prevalence was lower in Mexico- than in US-born Mexican-American women (POR = 0.70, 95% CI 0.50, 0.98) and men (POR = 0.63, 95% CI 0.40, 0.97). The difference was especially pronounced among subjects of lower socioeconomic status. Despite substantial differences in GBD risk factor distributions by birthplace, none could completely explain the prevalence difference.

CONCLUSIONS

The observation that GBD prevalence is higher among US-born Mexican Americans is consistent with research showing poorer health in this group. Further research is needed to identify strategies for reducing morbidity from GBD in Mexican Americans.

Prevalence and ethnic differences in gallbladder disease in the United States

BACKGROUND & AIMS

Gallbladder disease is one of the most common conditions in the United States, but its true prevalence is unknown. A national population-based survey was performed to determine the age, sex, and ethnic distribution of gallbladder disease in the United States.

METHODS

The third National Health and Nutrition Examination Survey (NHANES III) conducted gallbladder ultrasonography among a representative U.S. sample of more than 14, 000 persons. The diagnosis of gallbladder disease by detection of gallstones or cholecystectomy was made with excellent reproducibility.

RESULTS

An estimated 6.3 million men and 14.2 million women aged 20-74 years had gallbladder disease. Age-standardized prevalence was similar for non-Hispanic white (8. 6%) and Mexican American (8.9%) men, and both were higher than non-Hispanic black men (5.3%). These relationships persisted with multivariate adjustment. Among women, age-adjusted prevalence was highest for Mexican Americans (26.7%) followed by non-Hispanic whites (16.6%) and non-Hispanic blacks (13.9%). Among women, multivariate adjustment reduced the risk of gallbladder disease for both Mexican Americans and non-Hispanic blacks compared with non-Hispanic whites.

CONCLUSIONS

More than 20 million persons have gallbladder disease in the United States. Ethnic differences in gallbladder disease prevalence differed according to sex and were only partly explained by known risk factors.

Influence of ethnic origin on nuchal translucency screening for Down's syndrome

OBJECTIVE

To determine the influence of ethnic origin on access to and equity of nuchal translucency screening for Down's syndrome in a multiethnic population.

DESIGN

An observational study in a district general hospital with a large multiethnic population.

SUBJECTS

1944 women attending at a hospital antenatal clinic.

MAIN OUTCOME MEASURES

First-trimester fetal nuchal translucency measurements at 10-14 weeks in women from different ethnic groups.

RESULTS

The racial origin of the screened population was not significantly different from that of the population attending for initial antenatal examination. Multiple regression analysis showed a small but significant difference in nuchal translucency measurement between fetuses of different ethnic origin.

CONCLUSION

Nuchal translucency screening can be effectively and equitably delivered to a multiethnic population. Although there are significant differences in nuchal translucency measurement between ethnic groups, these differences are too small to require correction when nuchal translucency is used to screen for Down's syndrome.

The current status of methods for estimating the prevalence of human immunodeficiency virus in the United States of America

The prevalence of human immunodeficiency virus (HIV) infection can be estimated by two distinct methods. One method, back-calculation, is a complex statistical procedure that estimates the HIV epidemic curve. The second method is based on data from population-based surveys, which provide estimates of the proportion of persons infected with HIV within subgroups, and on the known or estimated population totals for these subgroups. Estimates from these methods are subject to substantial uncertainty and bias, both of which are difficult to quantify. We review recent use of these procedures to estimate HIV prevalence in the United States of America. We also summarize new data on the uncertainty and the bias in these estimates. Reliable estimates of HIV prevalence can be made only by synthesizing estimates from several procedures and by a comprehensive evaluation of relevant data. Future estimates of HIV prevalence will require modifications of these methods or the development of new methods.

Internalization of dengue virus-induced suppressor cytokine during transmission of the suppressor signal via macrophage

In dengue type 2 virus (DV)-induced suppressor T cell cascade TS1 cells secrete a suppressor cytokine (SF) which acts via syngeneic macrophages (M phi) to recruit TS2 cells. SF binds to both high and low affinity receptors (SF-R) on M phi. In the present study the fate of SF in M phi during transmission of suppressor signal is investigated. It was observed that SF bound to high affinity receptors internalized through receptor mediated endocytosis. This was inhibited by pretreatment of M phi with anti-SF-R-antiserum and didansylcadaverine, a potent inhibitor of endocytosis. Internalized SF was degraded by lysosomal activity as shown by inhibition of suppressor activity by pretreatment of M phi with monensin and NH4Cl. Degraded SF was transported to a site other than SF-R on M phi membrane for recruitment of TS2 cells. This was inhibited by anti-SF-antiserum. Transmission of suppressor signal is inhibited if M phi are treated first with H-2K-mAb and then with SF (shown earlier) but when M phi were treated first with SF and after 1 hr with H-2K-monoclonal antibody, the inhibition did not occur. As SF requires binding to H-2K and SF-R for mediation of suppression, the binding of H-2K occurred with degraded SF within the cell. Thus SF is internalized, degraded and binds to H-2K antigen before its recognition by native T cells.

Role of nitric oxide in transmission of dengue virus specific suppressor signal

Production of NO2- was maximum when peritoneal M phi was incubated with SF (40 mg) for 45 min. Pretreatment of M phi with anti-SF-antisera inhibited production of NO2- Pretreatment of M phi with NG monomethyl L-arginine (L-NMA) or arginase, an inhibitor of L-arginine dependent pathway, inhibited production of NO2- and transmission of suppressor signal in a dose-dependent manner. This indicates that NO and Ca2+ serve as intracellular signal in transmission of DV-induced suppressor signal.

Update on the seroepidemiology of human immunodeficiency virus in the United States household population: NHANES III, 1988-1994

To update the estimate of seroprevalence of HIV from the third National Health and Nutrition Examination Survey (NHANES III), data from the second phase of the survey were combined with previously published data to produce a more precise estimate. The testing was performed anonymously on 11,203 individuals 18-59 years of age examined from 1988 to 1994. Fifty-nine individuals were HIV positive, for an overall prevalence of 0.32%. The number of individuals living in households with HIV infection based on this estimate was 461,000, with a 95% confidence interval of 290,000-733,000. Analysis of nonresponse demonstrated that white and black men 40-59 years of age were least likely to participate in the survey. A sensitivity analysis demonstrated that this nonresponse may have biased the NHANES III estimate downward by 190,000 persons. Data from the second phase of the survey were used to analyze the association between drug use and HIV infection. Black women who used cocaine were 12 times more likely to be HIV positive compared with all tested black women (6.5% vs. 0.55%). This survey provides an estimate of HIV prevalence for individuals who reside in households but excludes some persons who are at higher risk for HIV infection, including prisoners and the homeless not residing in shelters.