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- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 2. |
- Budhavant, Krishnakant B., et al.
(författare)
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Physico-chemical characterization and sink mechanism of atmospheric aerosols over South-west India
- 2020
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Ingår i: Journal of Atmospheric Chemistry. - : Springer Science and Business Media LLC. - 0167-7764 .- 1573-0662. ; 77:1-2, s. 17-33
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Tidskriftsartikel (refereegranskat)abstract
- The properties of the atmospheric aerosols depend on the source region and on the modifications that occur during their transport in the air. We have studied physical and chemical properties of aerosols along with their sink mechanism over two locations in southwest India, an urban site (Pune) and well-established climate observatory at Sinhagad (SINH), which represents rural and high altitude site. The ground-based measurements of aerosols, together with their radiative properties in this study have provided means to understand the observed variability and the impact on the aerosol radiative properties effectively over this region. The annual mean elemental carbon concentration (3.4 mu g m(- 3)) at Pune was observed about three times higher compared to SINH (1.3 mu g m(- 3)), indicating strong emissions of carbon-rich aerosols at the urban location. Aerosol optical properties were derived using the OPAC model which were used to compute the Aerosol radiative forcing (ARF) over both stations calculated using SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer) model shows pronounced seasonal variations due to changes in aerosol optical depth and single scattering albedo at both locations. The year-round ARF was 4-5 times higher over Pune (31.4 +/- 3.5 Wm(- 2)) compared to SINH (7.2 +/- 1.1 Wm(- 2)). The atmospheric heating rate due to aerosols shows a similar pattern as ARF for these locations. The heating was higher in the wintertime, similar to 0.9-1.6 K day(- 1) at Pune, and similar to 0.3-0.6 K day(- 1) at SINH. The estimated scavenging ratio was found high for NO3- and Ca.(2+). The wet deposition fluxes of Cl-, SO42-, Na+, Mg2+ were observed higher for SINH as compared to Pune, due to the high amount of rain received at SINH.
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| 3. |
- Chandrika Ranjendra Nair, Hari Ram, 1989-, et al.
(författare)
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Aerosol demasking enhances climate warming over South Asia
- 2023
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Ingår i: npj Climate and Atmospheric Science. - 2397-3722. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic aerosols mask the climate warming caused by greenhouse gases (GHGs). In the absence of observational constraints, large uncertainties plague the estimates of this masking effect. Here we used the abrupt reduction in anthropogenic emissions observed during the COVID-19 societal slow-down to characterize the aerosol masking effect over South Asia. During this period, the aerosol loading decreased substantially and our observations reveal that the magnitude of this aerosol demasking corresponds to nearly three-fourths of the CO2-induced radiative forcing over South Asia. Concurrent measurements over the northern Indian Ocean unveiled a ~7% increase in the earth’s surface-reaching solar radiation (surface brightening). Aerosol-induced atmospheric solar heating decreased by ~0.4 K d−1. Our results reveal that under clear sky conditions, anthropogenic emissions over South Asia lead to nearly 1.4 W m−2 heating at the top of the atmosphere during the period March–May. A complete phase-out of today’s fossil fuel combustion to zero-emission renewables would result in rapid aerosol demasking, while the GHGs linger on.
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| 4. |
- Chandrika Ranjendra Nair, Hari Ram, 1989-, et al.
(författare)
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Aerosol demasking enhances climate warming over South Asia
- 2023
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Ingår i: npj Climate and Atmospheric Science. - 2397-3722. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic aerosols mask the climate warming caused by greenhouse gases (GHGs). In the absence of observational constraints, large uncertainties plague the estimates of this masking effect. Here we used the abrupt reduction in anthropogenic emissions observed during the COVID-19 societal slow-down to characterize the aerosol masking effect over South Asia. During this period, the aerosol loading decreased substantially and our observations reveal that the magnitude of this aerosol demasking corresponds to nearly three-fourths of the CO2-induced radiative forcing over South Asia. Concurrent measurements over the northern Indian Ocean unveiled a ~7% increase in the earth’s surface-reaching solar radiation (surface brightening). Aerosol-induced atmospheric solar heating decreased by ~0.4 K d−1. Our results reveal that under clear sky conditions, anthropogenic emissions over South Asia lead to nearly 1.4 W m−2 heating at the top of the atmosphere during the period March–May. A complete phase-out of today’s fossil fuel combustion to zero-emission renewables would result in rapid aerosol demasking, while the GHGs linger on.
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| 5. |
- Kaushik, Swati, et al.
(författare)
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Rapid and enhanced remote homology detection by cascading hidden Markov model searches in sequence space
- 2016
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Ingår i: Bioinformatics. - : Oxford University Press. - 1367-4803 .- 1367-4811. ; 32:3, s. 338-344
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Tidskriftsartikel (refereegranskat)abstract
- Motivation: In the post-genomic era, automatic annotation of protein sequences using computational homology-based methods is highly desirable. However, often protein sequences diverge to an extent where detection of homology and automatic annotation transfer is not straightforward. Sophisticated approaches to detect such distant relationships are needed. We propose a new approach to identify deep evolutionary relationships of proteins to overcome shortcomings of the availablemethods. Results: We have developed a method to identify remote homologues more effectively from any protein sequence database by using several cascading events with Hidden Markov Models (C-HMM). We have implemented clustering of hits and profile generation of hit clusters to effectively reduce the computational timings of the cascaded sequence searches. Our C-HMM approach could cover 94, 83 and 40% coverage at family, superfamily and fold levels, respectively, when applied on diverse protein folds. We have compared C-HMM with various remote homology detection methods and discuss the trade-offs between coverage and false positives.
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| 6. |
- Nair, Hari, 1989-
(författare)
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Absorption enhancement of black carbon aerosols and the aerosol-induced masking effect on warming over South Asia
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines the effects of black carbon (BC) and other aerosols on the regional climate, focusing on their climate-relevant optical properties and implications for radiative effects. We focus on South Asia, home to one-third of the worldwide population. The abrupt societal changes during the COVID-19 pandemic led to an unprecedented reduction in anthropogenic emissions and provided a unique opportunity to study the impact of aerosol demasking on global warming. The thesis revolves around insights obtained from three atmospheric receptor observatories intercepting the outflow from South Asia, complemented by remote sensing data and aerosol modeling. These are: Bangladesh Climate Observatory at Bhola (BCOB), positioned at the exit of the highly polluted Indo-Gangetic Plain (IGP), Maldives Climate Observatory at Hanimaadhoo (MCOH) in the Northern Indian Ocean, and Maldives Climate Observatory at Gan (MCOG) near the equator in the Indian Ocean. These observatories hence facilitate the measurements of aerosol properties from source regions to distant receptor environments and provide a comprehensive framework for assessing BC's regional climate impacts.The thesis offers insights into the changes in the sources of BC and the resultant climatic impact. The thesis quantifies the changes in the regional aerosol properties resulting from reduced anthropogenic emissions during the COVID-19 pandemic societal shutdown. The study reveals a substantial decrease in atmospheric aerosol loading, resulting in a reduction of the aerosol forcing roughly three-fourths of the magnitude of CO2-induced radiative forcing at the top of the atmosphere and a ~7% increase in surface-reaching solar radiation. This work also demonstrates a notable shift in relative contribution of BC sources at BCOB during the COVID period: fossil fuel contributions decreased from 49% to 35%, while C3 biomass burning increased from 31% to 55%, with C4 biomass remaining a minor source. Similarly, for MCOH, reflecting the outflow from the greater South Asian subcontinent, the contribution from fossil combustion decreased while C3 combustion increased.Further, the thesis explores the optical properties of BC, coating effects, and changes in mass absorption cross section (MAC) during long-range transport. The study shows a uniform MAC enhancement from water-soluble coatings of 1.6±0.5 across sites BCOB, MCOH and MCOG. However, the BC MAC increased by 80% in two separate studies from the IGP outflow at BCOB to the Indian Ocean receptor stations, suggesting a common underlying phenomenon. This mechanism is likely linked to scavenging fractionation occurring during the long-range transport of BC, which selectively filters out larger, lower BC MAC particles. This results in a residual population of finer, hydrophobic BC particles characterized by a notably higher MAC678 at the receptor observatories in Northern Indian Ocean. Additionally, throughout the transport from the BCOB to the MCOH, BC particles undergo a transformation, becoming more absorbent—akin to becoming "darker." This transformation is facilitated by the photochemical bleaching of organic carbon (OC) and in-cloud processes, which further contribute to the increase in BC- BC-MAC678. On the other hand, BrC-MAC decreased due to photochemical bleaching.The findings of this thesis, based on observations, enhance our understanding of the constantly changing optical and radiative impact of human-made aerosols in the highly significant South Asian emission region. This, in turn, enables better descriptions of the evolving aerosol characteristics in climate models and offers guidance for informed policy-making and the development of effective climate mitigation strategies.
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