Temporal evolution of measured climate forcing agents at South Pole, Antarctica

Greenhouse gas (GHG; mainly CO 2, CH 4, N 2O, CFC-11 and CFC-12) measurements for 22 years (1983-2004) have been analysed to evaluate the radiative forcing (RF) and temporal evolution at the South Pole. About 20 increase in growth rate of CO 2 has been observed during 1992-2004 compared to 1983-91. However, remarkable deceleration in the growth rate of CH 4, CFC-11 and CFC-12 has been observed. CO 2 radiative forcing has increased by ~49 during 2004 for 10 increase in CO 2 concentration during the last 22 years. RF due to CH 4 was found to be 0.47 Wm -2 in 1999 and since then has remained almost constant through 2004. The net RF has been observed to increase by 0.7 Wm -2 during 2004 compared to 1983, which corresponds to ~38 increase in the last 22 years. Growth rate of net RF decreased by ~22 during 1990-2004, compared to the growth rate during 1983-90. A global warming simulation made using the EdGCM model shows an increase in surface air temperature and sea surface temperature of about 1.7 oC and 1 oC respectively, in 2050 compared to 1958. In response to change in GHGs from 1958 to 2050, warming over the higher latitudes is greater than in the tropics and also increase in minimum temperature is greater than the increase in maximum temperature. Similarly, up to 50 change in snow-ice cover over some of the regions in the higher latitudes is observed with this simulation

Ozone in ambient air at a tropical megacity, Delhi: Characteristics, trends and cumulative ozone exposure indices

Seven year data of hourly surface ozone concentration is analyzed to study diurnal cycle, trends, excess of ozone levels above threshold value and cumulative ozone exposure indices at a tropical megacity, Delhi. The ozone levels clearly exhibit a diurnal cycle, similar to what has been found in other urban places. A sharp increase in the ozone levels during forenoon and a sharp decrease in the early afternoon can be observed. The average rate of increase in ozone concentration between 09 and 12 h has been observed to be 7.1 ppb h -1. We find that the daily maximum and daytime 8-h (10-17 h) ozone levels are increasing at a rate of about 1.7 (± 0.7) and 1.3 (± 0.56) ppb y-1, respectively. The directives on ozone pollution in ambient air provided by United Nations Economic Commission for Europe and World Health Organization for vegetation (AOT40) and human health protection were used to assess the air quality. The present surface ozone levels in the city are high enough to exceed "Critical Levels" which are considered to be safe for human health, vegetation and forest. The human health threshold was exceeded for up to ~45 days per year. The AOT40 (Accumulated exposure Over a Threshold of 40 ppb) threshold was exceeded significantly during winter (D-J-F) and pre-monsoon (M-A-M) (Rabi crop growing season) season in India. Translating AOT40 exceedances during pre-monsoon into relative yield loss we estimate yield loss of 22.7, 22.5, 16.3 and 5.5 for wheat, cotton, soybean and rice, respectively. © 2009 Springer Science+Business Media B.V

Cross platform microarray analysis for robust identification of differentially expressed genes

<p>Abstract</p> <p>Background</p> <p>Microarrays have been widely used for the analysis of gene expression and several commercial platforms are available. The combined use of multiple platforms can overcome the inherent biases of each approach, and may represent an alternative that is complementary to RT-PCR for identification of the more robust changes in gene expression profiles.</p> <p>In this paper, we combined statistical and functional analysis for the cross platform validation of two oligonucleotide-based technologies, Affymetrix (AFFX) and Applied Biosystems (ABI), and for the identification of differentially expressed genes.</p> <p>Results</p> <p>In this study, we analysed differentially expressed genes after treatment of an ovarian carcinoma cell line with a cell cycle inhibitor. Treated versus control RNA was analysed for expression of 16425 genes represented on both platforms.</p> <p>We assessed reproducibility between replicates for each platform using CAT plots, and we found it high for both, with better scores for AFFX. We then applied integrative correlation analysis to assess reproducibility of gene expression patterns across studies, bypassing the need for normalizing expression measurements across platforms. We identified 930 genes as differentially expressed on AFFX and 908 on ABI, with ~80% common to both platforms. Despite the different absolute values, the range of intensities of the differentially expressed genes detected by each platform was similar. ABI showed a slightly higher dynamic range in FC values, which might be associated with its detection system. 62/66 genes identified as differentially expressed by Microarray were confirmed by RT-PCR.</p> <p>Conclusion</p> <p>In this study we present a cross-platform validation of two oligonucleotide-based technologies, AFFX and ABI. We found good reproducibility between replicates, and showed that both platforms can be used to select differentially expressed genes with substantial agreement. Pathway analysis of the affected functions identified themes well in agreement with those expected for a cell cycle inhibitor, suggesting that this procedure is appropriate to facilitate the identification of biologically relevant signatures associated with compound treatment. The high rate of confirmation found for both common and platform-specific genes suggests that the combination of platforms may overcome biases related to probe design and technical features, thereby accelerating the identification of trustworthy differentially expressed genes.</p

Using C. elegans to discover therapeutic compounds for ageing-associated neurodegenerative diseases

Age-associated neurodegenerative disorders such as Alzheimer’s disease are a major public health challenge, due to the demographic increase in the proportion of older individuals in society. However, the relatively few currently approved drugs for these conditions provide only symptomatic relief. A major goal of neurodegeneration research is therefore to identify potential new therapeutic compounds that can slow or even reverse disease progression, either by impacting directly on the neurodegenerative process or by activating endogenous physiological neuroprotective mechanisms that decline with ageing. This requires model systems that can recapitulate key features of human neurodegenerative diseases that are also amenable to compound screening approaches. Mammalian models are very powerful, but are prohibitively expensive for high-throughput drug screens. Given the highly conserved neurological pathways between mammals and invertebrates, Caenorhabditis elegans has emerged as a powerful tool for neuroprotective compound screening. Here we describe how C. elegans has been used to model various human ageing-associated neurodegenerative diseases and provide an extensive list of compounds that have therapeutic activity in these worm models and so may have translational potential

Global distribution of tropospheric ozone and its precursors: A view from space

Satellite-borne tropospheric ozone measurements obtained from the tropospheric ozone residual (TOR) method, CO from the MOPITT (at 850 hPa level) measurements and NO2 from the SCIAMACHY measurements for the three-year period 2003-2005 have been utilized to examine the distribution of the pollutant sources and long-range transport on a global scale. Elevated tropospheric ozone columns have been observed over regions of high NO2 and CO concentrations in the northern and southern hemispheres. High levels of the tropospheric ozone column have been observed below about 5°S in the vicinity of the biomass burning regions and extend from continents out over the Atlantic during October. The seasonal distribution of tropospheric O3 and its precursors in the southern hemisphere shows the strong correlation with the seasonal variation of biomass burning in Africa and South America. Northern hemisphere summer shows the widespread ozone and CO pollution throughout the middle latitudes. The inter-hemispheric gradient of ozone and CO found to be decreased during October. Large-scale transport of the ozone and CO over the Atlantic and Pacific Oceans has been clearly identified. Strong inter-continental transport has been observed to occur from west to east along with the mid-latitude winds in the northern hemisphere

Year-to-year variation of ozone hole over Schirmacher region of East Antarctica: A synopsis of four-year measurement

During the 16th, 21st, 22nd and 23 rd Indian Antarctic expedition conducted in 1997, 2002-03 and 2004 respectively, measurement of columnar ozone have been made using MICROTOPS II Sun-photometer from the Indian station Maitri (70° 45â S, 11° 44â E). It is found that the ozone hole depth fluctuated from year-to-year. The minimum columnar ozone observed over Maitri was 135 (±9.3) DU, 185 (±12) DU, 126 (±9.7) DU and 159.8 (±8.8) DU during spring 1997, 2002, 2003 and 2004, respectively. Ozone concentration below 220 DU (nominal ozone threshold value) during Antarctic spring (day 225-365) over Maitri has been observed to be 45.1, 20.7, 62.7 and 60 in 1997, 2002, 2003 and 2004, respectively. The chemical loss of ozone (total ozone values below 220 DU) over Maitri during 2003 (day 225-365) was found to increase by a factor of 0.4 when compared to 1997, and by a factor of 2 when compared to 2002. The observations at Maitri also showed an event of major stratospheric warming during 2002. The ozone hole in the year 2002 was not found to be deep and further recovered quite early when compared to 1997, 2003 and 2004

Tropospheric ozone variability over the Indian coastline and adjacent land and sea

A tropospheric ozone variability study is carried out to investigate the spatial and temporal distribution over the coastline of the Indian peninsula and adjacent land and sea using NASA Langley Tropospheric Ozone Residual data set for the period 1979-2005.Astrong seasonal cycle has been observed with large variation (~ 55) over the upper eastern coast, followed by the upper and lower western coast, compared to the lower eastern coast (~ 33). A negative gradient in ozone concentration is observed along eastern and western coasts during summer (slope ~ -0.78 and -0.65) and a positive gradient (slope ~ 0.16 and 0.21) during winter. The same is observed over the adjacent land and sea along the coastline with slight variation. This change in gradient can be attributed to the anthropogenic emission of precursor gases that reinforce localized photochemical production of ozone. In addition, topography, transport, seasonality of emission of precursor gases and the solar insolation cycle play a vital role

Temporal and spatial variability of surface ozone at Delhi and Antarctica

This study deals with the temporal and spatial variability of 365 days; hourly mean surface ozone data for three different locations, New Delhi (a site of intense anthropogenic activity), Syowa and McMurdo stations in Antarctica (sites of clean background air). The analysis not only shows the seasonal and diurnal variation of O3 over New Delhi and Antarctica, but also provides statistics of means and variability on a temporal scale. Eight-hour (9-17 h) surface O3 concentration at New Delhi (2001) was recorded, which was 59 of the WHO (80 ppb) ambient air quality standard for ozone. Likewise, the monthly mean of daily maximum O3 during April and November (2001) was observed, which was 97 of the WHO ambient air quality standard for ozone that indicates the serious ozone pollution in New Delhi. Mean rate of daytime photochemical production of surface O3 at Delhi (2001) has been observed around 7.1 ppb h-1 between 6 and 12 h, while, Syowa and McMurdo stations showed photochemical loss of surface O3 during daylight hours of about 1 ppb and 0.2 ppb, respectively. The diurnal trend observed during summer at Syowa station shows a sign of daytime photochemical depletion. The photochemical loss of surface O3 during summer months with respect to the winter maximum ozone was observed to be about 56 and 64 at Syowa and McMurdo stations, respectively. The day-to-day variability at Syowa and McMurdo station suggests that the major loss term is a process in the sea ice zone

Altitudinal variation of surface aerosol with change in site: A comparative study

he study of size distribution of atmospheric aerosols is an important tool in understanding and managing aerosol effects on health, visibility and climate. The measurements of surface aerosols, both mass-size distribution and mass concentration, were carried out in the campaign mode at Leh (34°09'N, 77°34'E, 3441 m asl), Hanle (32°47'N, 78°58'E, 4517 m asl) and Delhi (28°39'N, 77°13'E, 220 m asl) during July 2003 to examine their variation with altitudinal and anthropogenic activity. A 15 channel portable particle size aerosol spectrometer GRIMM was used for carrying out the experiment. The aerosol spectrometer is equipped with class 3-B laser as the light source and uses a light scattering technology for single particle counts in the range > 0.3 µm to > 20.0 µm. During the period of observation at all three sites, the pattern of total mass concentration was found to be influenced by supermicron range mass concentration. The higher values of aerosol mass concentration observed at Delhi as compared with those observed at Leh and Hanle on all the channels show a large amount of anthropogenic activity taking place around Delhi vis-à-vis the other two sites. It is further observed that the mass-size distribution changes with the change in altitude and anthropogenic activit

Not Available

Not AvailableThis study describes the first confirmed report of contagious ecthyma in Black Bengal goats from Tripura state, a North-Eastern state of India situated at the Indo-Bangladesh border. Outbreaks were characterized by the high rates of morbidity (58-67%), low mortality (8-10%) and case fatality (11-15%). The etiology of the outbreaks was confirmed as orf virus (ORFV) by standard virological/serological and molecular techniques including sequence analysis of B2L, a major envelop protein gene of genus Parapoxvirus. Sequence and phylogenetic analysis based on B2L gene of ORFV isolates from Tripura revealed that they were closely related to each other and also to other Indian isolates, in particular to ORFV-Shahjahanpur 82/04 isolate from North India. They revealed several specific nucleotide/amino acid substitutions, namely G299A (G100D), G660A, C705T, C795T (N267D) and G872A (R291H) which may be of notable epidemiological significance. This report necessitates the systematic investigation of orf outbreaks in susceptible populations including wild species particularly at transboundary regions by use of rapid diagnostics to control the infection by deploying an effective vaccine/therapeutics and better managemental practices.Not Availabl