Temporal variability in aerosol characteristics and its radiative properties over Patiala, northwestern part of India: Impact of agricultural biomass burning emissions

A comprehensive measurements of aerosol optical depth (AOD), particulate matter (PM) and black carbon (BC) mass concentrations have been carried out over Patiala, a semi-urban site in northwest India during October 2008 to September 2010. The measured aerosol data was incorporated in an aerosol optical model to estimate various aerosol optical parameters, which were subsequently used for radiative forcing estimation. The measured AOD at 500 nm (AOD₅₀₀) shows a significant seasonal variability, with maximum value of 0.81 during post-monsoon (PoM) and minimum of 0.56 during winter season. The Ångström exponent (α) has higher values (i.e. more fine-mode fraction) during the PoM/winter periods, and lower (i.e. more coarse-mode fraction) during pre-monsoon (PrM). In contrast, turbidity coefficient (β) exhibits an opposite trend to α during the study period. BC mass concentration varies from 2.8 to 13.9 μg m^-3 (mean: 6.5 ± 3.2 μg m^-3) during the entire study period, with higher concentrations during PoM/winter and lower during PrM/monsoon seasons. The average single scattering albedo (SSA at 500 nm) values are 0.70, 0.72, 0.82 and 0.75 during PoM, winter, PrM and monsoon seasons, respectively. However, inter-seasonal and inter-annual variability in measured aerosol parameters are statistically insignificant at Patiala. These results suggest strong changes in emission sources, aerosol composition, meteorological parameters as well as transport of aerosols over the station. Higher values of AOD, α and BC, along with lower SSA during PoM season are attributed to agriculture biomass burning emissions over and around the station. The estimated aerosol radiative forcing within the atmosphere is positive (i.e. warming) during all the seasons with higher values (∼60 Wm^-2) during PoM-08/PoM-09 and lower (∼40 Wm^-2) during winter-09/PrM-10. The present study highlights the role of BC aerosols from agricultural biomass burning emissions during post-monsoon season for atmospheric warming at Patiala.

Chemical characterization of rainwater at a high-altitude site "Nainital" in the central Himalayas, India

The present study investigates the chemical composition of rainwater (RW) from a high-altitude site "Nainital" (1958 m above msl) in the central Himalaya region, to understand the influence of local, regional, and long-range transport of pollutants. A total of 55 (2 in pre-monsoon and 53 in monsoon) RW samples were collected during the study period (June-September 2012) and were analyzed for major anions and cations using an ion chromatograph. The pH of precipitation events ranged from 4.95 to 6.50 (average 5.6 ± 0.3) was observed during the monsoon period (near to the acidic), whereas during the pre-monsoon, the pH was 6.25 ± 0.49 (alkaline) over the study region; it is due the mixture of anthropogenic as well as the natural chemical constituents. The average ionic concentration (sum of measured chemical constituents) was ∼3 times higher during the pre-monsoon (986 ± 101 μeq/1) compared to that in the monsoon season (373 ± 37 μeq/1). This is mainly due to the presence of more natural aerosols in the pre-monsoon season which is also reflected in the pH of rainwater (average 6.25 ± 0.50) as well as ionic concentration. The chemical composition suggests that Ca²⁺ was the major contributor (34%) among cations, followed by Na⁺ (10%), K⁺ (8%), and Mg²⁺ (9%), whereas Cl^-, NO₃^-, and SO₄^2- contributed ∼13, 11, and 9%, respectively, among anions. The average ratio of acidic species (SO₄^2-/NO₃^-) is 1.56, suggesting 61 and 39% contribution of SO₄^2- and NO₃^-, respectively, which is very close to the estimated contribution of H₂SO₄ (60-70%) and HNO₃ (30-40%) in the precipitation samples. Neutralization factors for Ca²⁺, Mg²⁺, and NH₄⁺ in RW at Nainital are 4.94, 1.21, and 0.37, respectively, indicating their crucial role in neutralization of acidic species. The non-sea-salt (NSS) contribution to total Ca²⁺, K⁺, and Mg²⁺ is estimated to be ∼98, 97, and 74%, respectively, suggesting the dominance of crustal sources for cations. In contrast, the NSS contribution to the total Cl^- and SO₄^2- is 16 and 69% indicating their anthropogenic origin, respectively. Principle component analysis also suggests that the first factor (i.e., natural sources, mainly dust, and sea-salts) accounts for ∼33% variance, whereas the second factor (i.e., fossil fuel and biomass burning) accounts for ∼18% variance of the measured ionic composition. The remaining contributions are attributed to the mixed emission sources and transport of pollutants from Indo-Gangetic Plain (IGP) and western parts of India. The results of the present study reveal a significant contribution of crustal and anthropogenic sources in the RW and neutralization processes in the central Himalaya.

Aerosol optical properties and radiative effects over Manora Peak in the Himalayan foothills: seasonal variability and role of transported aerosols

The higher altitude regions of Himalayas and Tibetan Plateau are influenced by the dust and black carbon (BC) aerosols from the emissions and long-range transport from the adjoining areas. In this study, we present impacts of advection of polluted air masses of natural and anthropogenic emissions, on aerosol optical and radiative properties at Manora Peak (~2000 m amsl) in central Himalaya over a period of more than two years (February 2006-May 2008). We used the most updated and comprehensive data of chemical and optical properties available in one of the most climatically sensitive region, the Himalaya, to estimate atmospheric radiative forcing and heating rate. Aerosol optical depth (AOD) was found to vary from 0.04 to 0.45 with significantly higher values in summer mainly due to an increase in mineral dust and biomass burning aerosols due to transport. In contrast, single scattering albedo (SSA) varied from 0.74 to 0.88 with relatively lower values during summer, suggesting an increase in absorbing BC and mineral dust aerosols. As a result, a large positive atmospheric radiative forcing (about 28 ± 5 Wm(-2)) and high values of corresponding heating rate (0.80 ± 0.14 Kday(-1)) has been found during summer. During the entire observation period, radiative forcing at the top of the atmosphere varied from -2 to +14 Wm(-2) and from -3 to -50 Wm(-2) at the surface whereas atmospheric forcing was in the range of 3 to 65 Wm(-2) resulting in a heating rate of 0.1-1.8 Kday(-1).

Characterization of carbonaceous aerosols over Delhi in Ganga basin: seasonal variability and possible sources

The mass concentration of carbonaceous species, organic carbon (OC), and elemental carbon (EC) using a semicontinuous thermo-optical EC-OC analyzer, and black carbon (BC) using an Aethalometer were measured simultaneously at an urban mega city Delhi in Ganga basin from January 2011 to May 2012. The concentrations of OC, EC, and BC exhibit seasonal variability, and their concentrations were ∼2 times higher during winter (OC 38.1 ± 17.9 μg m(-3), EC 15.8 ± 7.3 μg m(-3), and BC 10.1 ± 5.3 μg m(-3)) compared to those in summer (OC 14.1 ± 4.3 μg m(-3), EC 7.5 ± 1.5 μg m(-3), and BC 4.9 ± 1.5 μg m(-3)). A significant correlation between OC and EC (R = 0.95, n = 232) indicate their common emission sources with relatively lower OC/EC ratio (range 1.0-3.6, mean 2.2 ± 0.5) suggests fossil fuel emission as a major source of carbonaceous aerosols over the station. On average, mass concentration of EC was found to be ∼38 % higher than BC during the study period. The measured absorption coefficient (babs) was significantly correlated with EC, suggesting EC as a major absorbing species in ambient aerosols at Delhi. Furthermore, the estimated mass absorption efficiency (σabs) values are similar during winter (5.0 ± 1.5 m(2) g(-1)) and summer (4.8 ± 2.8 m(2) g(-1)). Significantly high aerosol loading of carbonaceous species emphasize an urgent need to focus on air quality management and proper impact assessment on health perspective in these regions.

Checklists and crisis management in surgical emergencies

Using checklists to improve clinical outcomes

Surgical safety

Clinician led

A high-performance liquid chromatography-tandem mass spectrometric method for the determination of pharmacokinetics of ganaxolone in rat, monkey, dog and human plasma

A method for determining concentration levels of ganaxolone in rat, monkey, dog and human plasma was validated in the range of 5-1500 ng/ml using a 200-microl plasma sample volume. This validation report describes the linearity, specificity. sensitivity, reproducibility, accuracy, recovery and stability of the analytical method. The inter-day C.V. ranged from 0.5 to 9.2%, intra-day C.V. from 0.7 to 8.8% and intra-day accuracy (mean absolute percentage difference) ranged from 0.0 to 14.0% for rat, monkey, dog and human plasma. The method was used for the routine analysis of ganaxolone in rat, monkey, dog and human plasma and summary of the pharmacokinetic data are presented.

Mixing in process vessels used in biopharmaceutical manufacturing

The use of nonbaffled vessels for mixing applications is becoming common in the biopharmaceutical industry but is not sufficiently well studied. Orientation of the impellers off-centered and/or at an angle is necessary to enhance mixing and eliminate swirling that would result without a baffle in a standard tank. This study focuses on characterizing mixing in vessels with the hydrofoil axial flow impellers mounted off-center at 10 degrees to the vertical. Geometrically similar vessels ranging from 100 to 5000 L working volume were used in this study. Mixing performance was successfully correlated to vessel geometric factors.

Energy expenditure and ventilatory responses during Siddhasana--a yogic seated posture

Reports of energy expenditure and ventilatory responses to yogic seated posture of Siddhasana are lacking in literature. Various cardio-ventilatory responses were studied in states of the horizontal supine, chair-sitting and Siddhasana. It was observed that sitting in Siddhasana posture was characterised by greater minute ventilation, larger tidal volume, higher oxygen consumption, greater CO2 elimination, higher heart frequency greater oxygen pulse and lesser as compared with other two postures. These observations suggest that Siddhasana is a mild type of exercise and may have its application in conditions of low cardio-respiratory reserves especially in individuals in whom heavy exercises are contra-indicated.

Energy expenditure and ventilatory responses during Virasana--a yogic standing posture

Energy expenditure and ventilatory responses to yogic standing posture of Virasana were studied on 10 healthy men (25-37 years of age). The results of various responses respectively to the horizontal supine, Chair-sitting and Virasana were: Minute Ventilation (VE) 7.64, 8.61 and 18.67 L/min; Respiratory Frequency (FR) 15.71, 15.70 and 21.45 Breath/min; Tidal Volume (VT) 0.496, 0.544 and 0.827 L/min; Oxygen consumption (VO2) 0.127, 0.234 and 0.573 L/min; Carbondioxide Elimination (VCO2) 0.127, 0.134 and 0.420 L/min; Respiratory Exchange Ratio (RER) 0.58, 0.57 and 0.69; Heart Frequency (FH) 65.2, 74.5 and 104.4 beats/min; Oxygen Pulse (O2P) 3.32, 3.17 and 5.45 ml/beat; Ventilatory Equivalent (VE-EQ) 36.78, 37.12 and 33.85; Multiple of Resting VO2 (METS) 0.96, 1.05 and 2.53 and Metabolic Cost (MC) 1.04, 1.13 and 2.76 Cal/min. Virasana posture was characterised by higher VE, FR, VT, VO2, VCO2, FH and O2P with lesser VE-EQ. The observations suggest that Virasana induces temporarily a hypermetabolic state characterised by enhanced sympathetic nervous system activity which gets inhibited during the adoption of resting supine shavasana posture.

Effect of yoga training on exercise tolerance in adolescents with childhood asthma

Forty six young asthmatics with a history of childhood asthma were admitted for yoga training. Effects of training on resting pulmonary functions, exercise capacity, and exercise-induced bronchial lability index were measured. Yoga training resulted in a significant increase in pulmonary function and exercise capacity. A follow-up study spanning two years showed a good response with reduced symptom score and drug requirements in these subjects. It is concluded that yoga training is beneficial for young asthmatics.