Aerosol black carbon radiative forcing at an industrial city in northern India

During a comprehensive aerosol field campaign as part of ISRO-GBP,extensive measurements of aerosol black carbon were made during December 2004, for the first time, at Kanpur, an urban continent allocation in northern India. BC diurnal variation is associated with changes in boundary layer mixing and anthropogenic activities. BC concentration in Kanpur is comparable to those measured in other megacities of India but much higher than in similar locations of Europe,USA and Asia. High BC concentration is found both in absolute terms $(6-20 \mu g m^{-3} )$ and mass fraction (similar to 10%) yielding very low single scattering albedo (0.76). The estimated surface forcing is as high as $-62 +/- 23 W m^{-2}$ and top of the atmosphere (TOA) forcing is $+9 +/- 3 W m^{-2}$, which means the atmospheric absorption is $+71 Wm^{-2}$. The short wave atmospheric absorption translates to a lower atmospheric heating of similar to 1.8 degrees K/day. Large surface cooling and lower atmospheric heating may have impacts to regional climate

Ultrashort-Lived Non-Rydberg Doubly Excited Resonances Observed in Molecular Photoionization

The N2 1sB 2 Xd dispersed fluorescence from photon excited N2 molecules has been measured in the 19–34 eV excitation range, where our theory predicts the existence of non-Rydberg doubly excited resonances which autoionize in the sub-fs regime into the N2 1 B2S1u ionic state. The experimentally deduced vibrational branching ratios sy0 ­ 1dysy0 ­ 0d revealed five prominent features, four of which could be identified as such doubly excited resonances based on the lowest order of the many-body perturbation theory. [S0031-9007(96)00230-X]NR</p

Enhanced layer of black carbon in a north Indian industrial city

During a comprehensive aerosol field campaign as part of Indian SpaceResearch Organization Geosphere Biosphere Programme (ISRO-GBP),aircraft measurements of vertical profiles of aerosol black carbon (BC)were made during winter, for the first time, at Kanpur (80 degrees 20'Eand 26 degrees 26'N), an urban industrial location in Northern India.Two vertical profiling from the same day (morning and afternoon) of BCshowed that BC decreases with height up to similar to 600 m and thenincreases up to 900 m before becoming more or less constant withheight. Potential temperature profile, derived from concurrentmeasurements of temperature, shows a stable layer at the same altitudewhere BC shows increased concentration. This vertical structure ofboundary layer was further confirmed by separate temperature andrelative humidity profiles obtained from balloonsondes during December.The increased BC at similar to 900 m suggests the presence of enhancedBC layer, which will have significant implications to BC radiativeforcing and modifying cloud properties

NIMS: a database on nucleobase compounds and their interactions in macromolecular structures

The intense exploration of nucleotide-binding protein structures has created a whirlwind in the field of structural biology and bioinformatics. This has led to the conception and birth of NIMS. This database is a collection of detailed data on the nucleobases, nucleosides and nucleotides, along with their analogues as well as the protein structures to which they bind. Interaction details such as the interacting residues and all associated values have been made available. As a pioneering step, the diffraction precision index for protein structures, the atomic uncertainty for each atom, and the computed errors on the interatomic distances and angles are available in the database. Apart from the above, provision has been made to visualize the three-dimensional structures of both ligands and protein-ligand structures and their interactions in Jmol as well as JSmol. One of the salient features of NIMS is that it has been interfaced with a user-friendly and query-based efficient search engine. It was conceived and developed with the aim of serving a significant section of researchers working in the area of protein and nucleobase complexes. NIMS is freely available online at http://iris.physics.iisc.ernet.in/nims and it is hoped that it will prove to be an invaluable asset

Online_DPI: a web server to calculate the diffraction precision index for a protein structure

An online computing server, Online_DPI (where DPI denotes the diffraction precision index), has been created to calculate the `Cruickshank DPI' value for a given three-dimensional protein or macromolecular structure. It also estimates the atomic coordinate error for all the atoms available in the structure. It is an easy-to-use web server that enables users to visualize the computed values dynamically on the client machine. Users can provide the Protein Data Bank (PDB) identification code or upload the three-dimensional atomic coordinates from the client machine. The computed DPI value for the structure and the atomic coordinate errors for all the atoms are included in the revised PDB file. Further, users can graphically view the atomic coordinate error along with `temperature factors' (i.e. atomic displacement parameters). In addition, the computing engine is interfaced with an up-to-date local copy of the Protein Data Bank. New entries are updated every week, and thus users can access all the structures available in the Protein Data Bank. The computing engine is freely accessible online at http://cluster.physics.iisc.ernet.in/dpi/

Spatial distribution of aerosol black carbon over India during pre-monsoon season

Aerosol black carbon (BC) mass concentrations (BC), measured continuously during a mutli-platform field experiment, Integrated Campaign for Aerosols gases and Radiation Budget (ICARB, March-May 2006), from a network of eight observatories spread over geographically distinct environments of India, (which included five mainland stations, one highland station, and two island stations (one each in Arabian Sea and Bay of Bengal)) are examined for their spatio-temporal characteristics. During the period of study, BC showed large variations across the country, with values ranging from 27 μg m-3 over industrial/urban locations to as low as 0.065 μg m-3 over the Arabian Sea. For all mainland stations, BC remained high compared to highland as well as island stations. Among the island stations, Port Blair (PBR) had higher concentration of BC, compared to Minicoy (MCY), implying more absorbing nature of Bay of Bengal aerosols than Arabian Sea. The highland station Nainital (NTL), in the central Himalayas, showed low values of BC, comparable or even lower than that of the island station PBR, indicating the prevalence of cleaner environment over there. An examination of the changes in the mean temporal features, as the season advances from winter (December-February) to pre-monsoon (March-May), revealed that: (a) Diurnal variations were pronounced over all the mainland stations, with an afternoon low and a nighttime high; (b) At the islands, the diurnal variations, though resembled those over the mainlands, were less pronounced; and (c) In contrast to this, highland station showed an opposite pattern with an afternoon high and a late night or early morning low. The diurnal variations at all stations are mainly caused by the dynamics of local Atmospheric Boundary Layer (ABL). At the entire mainland as well as island stations (except HYD and DEL), BC showed a decreasing trend from January to May. This is attributed to the increased convective mixing and to the resulting enhanced vertical dispersal of species in the ABL. In addition, large short-period modulations were observed at DEL and HYD, which appeared to be episodic. An examination of this in the light of the MODIS-derived fire count data over India along with the back-trajectory analysis revealed that advection of BC from extensive forest fires and biomass-burning regions upwind were largely responsible for this episodic enhancement in BC at HYD and DEL

Hydrogen Bonds Computing Server (HBCS): an online web server to compute hydrogen-bond interactions and their precision

Hydrogen bonds in biological macromolecules play significant structural and functional roles. They are the key contributors to most of the interactions without which no living system exists. In view of this, a web-based computing server, the Hydrogen Bonds Computing Server (HBCS), has been developed to compute hydrogen-bond interactions and their standard deviations for any given macromolecular structure. The computing server is connected to a locally maintained Protein Data Bank (PDB) archive. Thus, the user can calculate the above parameters for any deposited structure, and options have also been provided for the user to upload a structure in PDB format from the client machine. In addition, the server has been interfaced with the molecular viewers Jmol and JSmol to visualize the hydrogen-bond interactions. The proposed server is freely available and accessible via the World Wide Web at http://bioserver1.physics.iisc.ernet.in/hbcs/