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Carbon Sequestration Potential of the Forest Ecosystems in the Western Ghats, a Global Biodiversity Hotspot
No full textGlobal warming with the burgeoning anthropogenic greenhouse gas (GHG) emissions (400 parts per million from 280 ppm CO2 emissions of pre-industrial era) has altered climate, eroding the ecosystem productivity and sustenance of water, affecting the livelihood of people. The anthropogenic activities such as burning fossil fuel, power generation, agriculture, industry, polluting water bodies and urban activities are responsible for increasing GHG footprint of which 72% constitute CO2. GHG footprint needs to be in balance with sequestration of carbon to sustain ecosystem functions. Forests are the major carbon sinks (about 45%) that aid in mitigating global warming. The current research focusses on the carbon budgeting through quantification of emissions and sinks in the forest ecosystems and changes in climatic conditions of Western Ghats. This would help in evolving appropriate mitigation strategies toward sustainable management of forests and mitigate impacts of global warming. The land-use land-cover (LULC) dynamics are the prime driver of climate change due to the loss of carbon sequestration potential as well as emissions. The Western Ghats are one among 36 global biodiversity hotspots and forests in this region sequester atmospheric carbon, which aid in moderating the global climate and sustaining water to ensure water and food security in the peninsular India. Assessment of LULC dynamics using temporal remote sensing data shows the decline of evergreen forest by 5% with an increase in agriculture, plantations and built-up area. The interior or intact forests have declined by 10%, and they are now confined to protected areas. The simulation of likely changes indicates that the region will have only 10% evergreen cover and 17% agriculture, 40% plantations and 5% built-up. Quantification of carbon reveals that the WG forest ecosystem holds 1.23 MGg (million gigagrams or Gt) in vegetation and soils. The annual incremental carbon is about 37,507.3 Gg, (or 37.5 million tons, Mt) and the highest in the forests of Karnataka part of WG. Simulation of the likely changes in carbon content indicates the loss of 0.23 MGg (2018-2031) carbon sequestration potential under business as usual scenario. The conservation scenario depicts an increase in carbon sequestration potential of WG forests with the protection. Sequestered carbon in WG is about INR 100 billion (30) per tonne. Large-scale land-cover changes leading to deforestation has contributed to an increase in mean temperature by 0.5 degrees C and decline in rainy days, which necessitates evolving prudent landscape management strategies involving all stakeholders for conservation of ecologically fragile WG. This will enhance the ability of forests to sequester atmospheric carbon and climate moderation, with the sustenance of ecosystem goods and services
Definition of the chalcogen bond (IUPAC Recommendations 2019)
No full textThis recommendation proposes a definition for the term ``chalcogen bond''; it is recommended the term is used to designate the specific subset of inter- and intramolecular interactions formed by chalcogen atoms wherein the Group 16 element is the electrophilic site
An expanded ND2 phylogeny of the brookii and prashadi groups with the description of three new Indian Hemidactylus Oken (Squamata: Gekkonidae)
No full textWe present an expanded ND2 phylogeny of the brookii and prashadi groups of Indian Hemidactylus. While relationships within the clades are not well resolved, we recover many well supported subclades and a number of deeply divergent lineages within each clade. We use morphological data to describe three of these divergent lineages as new species; Hemidactylus kolliensis sp. nov., a member of the prashadi group from high elevation in the Kollimalai Massif in Tamil Nadu, Hemidactylus chikhaldaraensis sp. nov. and Hemidactylus sankariensis sp. nov., both members of the brookii group, are described from high elevation of the Satpuras in Maharashtra and low elevation of Tamil Nadu, respectively. The three new species exhibit > 15% divergence for the ND2 gene from their phylogenetic sisters and differ in a number of morphological characters from all Indian congeners. The discovery of three more endemic Hemidactylus species from rocky habitats suggests that many more remain to be discovered across India
Assessing predictions on fitness effects of missense variants in calmodulin
No full textThis paper reports the evaluation of predictions for the ``CALM1'' challenge in the fifth round of the Critical Assessment of Genome Interpretation held in 2018. In the challenge, the participants were asked to predict effects on yeast growth caused by missense variants of human calmodulin, a highly conserved protein in eukaryotic cells sensing calcium concentration. The performance of predictors implementing different algorithms and methods is similar. Most predictors are able to identify the deleterious or tolerated variants with modest accuracy, with a baseline predictor based purely on sequence conservation slightly outperforming the submitted predictions. Nevertheless, we think that the accuracy of predictions remains far from satisfactory, and the field awaits substantial improvements. The most poorly predicted variants in this round surround functional CALM1 sites that bind calcium or peptide, which suggests that better incorporation of structural analysis may help improve predictions
Structural, optical and Mossbauer spectroscopic investigations on the environment of Fe in Fe-doped ZnO (Zn1-xFexO) ceramics synthesized by solution combustion method
No full textA series of Fe-doped ZnO (Zn1-xFexO, = 0, 0.01, 0.03, 0.05, 0.07 and 0.10) samples were synthesized by solution combustion synthesis method using metal nitrates as oxidizers and glycine as fuel. A spongy network-type microstructure is observed by the SEM micrographs of all the synthesized samples. For Fe concentration lower than 0.05 (x <= 0.05), formation of phase-pure wurtzite (hexagonal) structured Zn1-xFexO powder with P6(3)mc space group was confirmed from the X-ray diffraction results. However, for x >= 0.07, precipitation of ZnFe2O4 impurity phase was observed. Hence, the solubility limit for Fe in ZnO lattice is about x = 0.05 for the samples synthesized by solution combustion method. Two quadruple doublets observed in the Fe-57-Mossbauer spectra for each of the samples suggest that paramagnetic Fe3+ cations occupy two different lattice sites in the ZnO structure; they are the substitutional sites (1) without distortion of the surrounding structure and (2) with distortion due to the defects present in the surrounding structure. In the DRS spectra, an Urbach-like tail was observed in the band gap region, indicating that Fe-doping in the ZnO lattice modifies the electronic structure and enhances the absorption of visible light. Furthermore, the Kubelka-Munk plots suggest the presence of two different local structures validating the Mossbauer results. We studied the photocatalytic degradation of methylene blue dye using these Fe doped ZnO samples as catalysts and the studies revealed that presence of Fe could lead to the formation of carbonaceous material on the surface of the solution combustion synthesized Zn1-xFexO samples. Overall, our results demonstrate the structural characteristics of Fe in Fe-doped ZnO samples synthesized by solution combustion method
Electronic Structure of a Graphene-like Artificial Crystal of NdNiO3
No full textArtificial complex-oxide heterostructures containing ultrathin buried layers grown along the pseudocubic 111] direction have been predicted to host a plethora of exotic quantum states arising from the graphene-like lattice geometry and the interplay between strong electronic correlations and band topology. To date, however, electronic-structural investigations of such atomic layers remain an immense challenge due to the shortcomings of conventional surface-sensitive probes with typical information depths of a few angstroms. Here, we use a combination of bulk-sensitive soft X-ray angle-resolved photoelectron spectroscopy (SX-ARPES), hard X-ray photoelectron spectroscopy (HAXPES), and state-of-the-art first-principles calculations to demonstrate a direct and robust method for extracting momentum-resolved and angle-integrated valence-band electronic structure of an ultrathin buckled graphene-like layer of NdNiO3 confined between two 4-unit cell-thick layers of insulating LaAlO3. The momentum-resolved dispersion of the buried Ni d states near the Fermi level obtained via SX-ARPES is in excellent agreement with the first-principles calculations and establishes the realization of an antiferro-orbital order in this artificial lattice. The HAXPES measurements reveal the presence of a valence-band bandgap of 265 meV. Our findings open a promising avenue for designing and investigating quantum states of matter with exotic order and topology in a few buried layers
Efficient and Distributed Generalized Canonical Correlation Analysis for Big Multiview Data
No full textGeneralized canonical correlation analysis (GCCA) integrates information from data samples that are acquired at multiple feature spaces (or `views') to produce low-dimensional representations-which is an extension of classical two-view CCA. Since the 1960s, (G)CCA has attracted much attention in statistics, machine learning, and data mining because of its importance in data analytics. Despite these efforts, the existing GCCA algorithms have serious complexity issues. The memory and computational complexities of the existing algorithms usually grow as a quadratic and cubic function of the problem dimension (the number of samples / features), respectively-e.g., handling views with approximate to 1,000 features using such algorithms already occupies approximate to 10(6) memory and the per-iteration complexity is approximate to 10(9) flops-which makes it hard to push these methods much further. To circumvent such difficulties, we first propose a GCCA algorithm whose memory and computational costs scale linearly in the problem dimension and the number of nonzero data elements, respectively. Consequently, the proposed algorithm can easily handle very large sparse views whose sample and feature dimensions both exceed approximate to 100,000. Our second contribution lies in proposing two distributed algorithms for GCCA, which compute the canonical components of different views in parallel and thus can further reduce the runtime significantly if multiple computing agents are available. We provide detailed convergence analyses of the proposed algorithms and show that all the large-scale GCCA algorithms converge to a Karush-Kuhn-Tucker (KKT) point at least sublinearly. Judiciously designed synthetic and real-data experiments are employed to showcase the effectiveness of the proposed algorithms
The mammalian host protein DAP5 facilitates the initial round of translation of Coxsackievirus B3 RNA
No full textDuring enteroviral infections, the canonical translation factor eukaryotic translation initiation factor 4 ? I (eIF4GI) is cleaved by viral protease 2A. The resulting C-terminal fragment is recruited by the viral internal ribosome entry site (IRES) for efficient translation of the viral RNA. However, the 2A protease is not present in the viral capsid and is synthesized only after the initial round of translation. This presents the conundrum of how the initial round of translation occurs in the absence of the C-terminal eIF4GI fragment. Interestingly, the host protein DAP5 (also known as p97, eIF4GIII, and eIF4G2), an isoform of eIF4GI, closely resembles the eIF4GI C-terminal fragment produced after 2A protease?mediated cleavage. Using the Coxsackievirus B3 (CVB3) IRES as a model system, here we demonstrate that DAP5, but not the full-length eIF4GI, is required for CVB3 IRES activity for translation of input viral RNA. Additionally, we show that DAP5 is specifically required by type I IRES but not by type II or type III IRES, in which cleavage of eIF4GI has not been observed. We observed that both DAP5 and C-terminal eIF4GI interact with CVB3 IRES in the same region, but DAP5 exhibits a lower affinity for CVB3 IRES compared with the C-terminal eIF4GI fragment. It appears that DAP5 is required for the initial round of viral RNA translation by sustaining a basal level of CVB3 IRES activity. This activity leads to expression of 2A protease and consequent robust CVB3 IRES-mediated translation by the C-terminal eIF4GI fragment
Spatial and temporal variability in energy and water vapour fluxes observed at seven sites on the Indian subcontinent during 2017
No full textUnder the INCOMPASS project, state of the art eddy-covariance based surface flux measurement systems were installed at eight locations across India. These sites cover different climatic conditions, land use and land cover, and water management practices. Here we present the initial analysis of the measurements taken at seven sites mainly focusing on the year 2017, quantifying for the first time the remarkable contrasts in evaporative fraction across the seasons, climate zones and land management practices of the Indian subcontinent. With the exception of Jaisalmer which is the driest of the places studied, all the sites maintain values of evaporative fraction above 0.5 after the monsoon through to November. By contrast, for those sites with natural vegetation or rain-fed agriculture, evaporative fraction remains below 0.3 for the dry January-May period. In the middle Gangetic Plain area, irrigation and pre-monsoon showers together maintain evaporative fraction above 0.5 between January and June. It is also observed that different variables exhibit different intraseasonal variation characteristics even at one site. Except for Samastipur which is situated in the middle Indo-Gangetic Plains, wind speed shows spectral peak at a smaller time-scale compared to sensible and latent heat fluxes