317 research outputs found
Parametrization of dark energy equation of state Revisited
A comparative study of various parametrizations of the dark energy equation
of state is made. Astrophysical constraints from LSS, CMB and BBN are laid down
to test the physical viability and cosmological compatibility of these
parametrizations. A critical evaluation of the 4-index parametrizations reveals
that Hannestad-M\"{o}rtsell as well as Lee parametrizations are simple and
transparent in probing the evolution of the dark energy during the expansion
history of the universe and they satisfy the LSS, CMB and BBN constraints on
the dark energy density parameter for the best fit values.Comment: 11 page
Biomass and carbon stocks in mangrove stands of Kadalundi estuarine wetland, south-west coast of India
Mangroves are keystone ecosystems which provide numerous environmental services. Mangroves assume significance as standing stores of sequestered atmospheric carbon and are therefore, important in the light of climate change mitigation. In this study, we attempted to assess the biomass of mangroves in the Kadalundi wetland, south-west coast of India and evaluated the potential of these mangroves to sequester and store carbon. The C-stocks of above-ground and root biomass were 83.32±11.06 t C ha-1 and 34.96±4.30 t C ha-1 respectively, while the C-stock in sediment was estimated to be 63.87±8.67 t C ha-1. The estimates of mean combined C-stocks in the mangrove biomass and sediment of Kadalundi shows that this estuarine mangrove wetland stored 182.15 t C ha-1, which was equivalent to 668.48 t CO2 ha-1. The mangroves which cover an area of 13.23 ha in the Kadalundi wetland is assumed to have a potential to sequester and store a substantial quantity of 2,409.84 t C which is equivalent to 8,844.11 t CO2. The study underscores the importance of these intertidal forests for climate change mitigation and stresses the importance of protecting the mangroves which provide many other important ecosystem services that benefit communities
Assessment of Biomass and Carbon Stocks in Mangroves of Thalassery Estuarine Wetland of Kerala, South West Coast of India
The mangrove ecosystems render many goods and services ranging from coastal protection to climate regulation. These ecosystems are also reservoirs of carbon stocks, due to their ability to sequester and store carbon in their biomass and the underlying sediment, and therefore significant in view of the climate change mitigation. The present study attempted to assess the biomass and carbon stock of mangroves of Thalassery estuarine wetland of Kerala, south-west coast of India. We assessed the carbon stocks of three carbon pools viz., above-ground, below-ground (root) and sediment. A total of eight species of mangroves were recorded from the Thalassery estuarine wetland, and of these, Avicennia officinalis was the dominant species with an average tree density of 729.37 individuals ha-1 and contributed most (45.05±23.79 t ha-1) to the total carbon. The overall mean above-ground biomass was 189.26±97.80 t ha-1, while the overall mean root biomass was 83.06±40.48 t ha-1. The estimated mean above-ground carbon was 94.63±48.90 t C ha-1, while the mean carbon stock in root and sediment were 41.53±20.24 t C ha-1 and 17.48±7.30 t C ha-1, respectively. In the present study, the estimates of mean combined C-stocks in mangrove and sediment showed that the mangroves of Thalassery estuarine wetland stored 153.64 t C ha-1 which was equivalent to 563.86 t CO2 ha-1. The mangroves of Thalassery wetland cover an area of approximately 5.8 ha and thus it can be assumed that this wetland has the potential to sequester and store 891.11 t C, equivalent to an estimated amount of 3270.37 t CO2. The study reinforces the importance of mangrove forests as useful carbon sinks and the need for protection of these critical habitats in the light of climate change mitigation
Evaluation of suitable sites for mud crab farming in Ratnagiri District of Maharashtra, India
The State of Maharashtra has vast stretches of estuaries, creeks and
mangrove swamps, which offers great potential for aquaculture,
particularly for mud crab farming. In view of the natural resources and
market potential for mud crab, the Department of Forests, Government of
Maharashtra plans to promote mud crab farming through a novel
approach, which aims at providing livelihood support to the local
communities utilizing the mangrove wetlands; thereby the local
communities also shoulder the responsibility of conservation of mangroves.
In this backdrop, a study was conducted to identify the suitable sites for
sustainable mud crab culture, in GIS environment, based on various
physical and environmental criteria including topography, soil types, landuse
systems, vegetation, water quality, water availability, salinity, risks of
flooding, infrastructure, seed resources and availability, market and
support services. The brackishwater stretches of Anjarle, Kelshi, Aade,
Velas and Ansure in the Ratnagiri district of Maharashtra were studied,
and all study stations had patchy to thick mangrove vegetation. The major
mangrove species encountered were: Avicennia marina, Avicennia
officinalis, Sonneratia caseolaris, Rhizophora mucronata and Acanthus
ilicifolius. The pH of water was near-neutral to alkaline, whereas dissolved
oxygen levels were found to be within the ideal range. The salinity of the
tidal creeks ranged from 7.24 ppt (Velas) to 35.9 ppt (Ansure) which
generally varies with the tide. The ammonia levels which ranged from 0
(Aade and Ansure) to 0.5 ppm (Kelshi), falls within the safe levels for
Available online at: www.mbai.org.in doi: 10.6024/jmbai.2017.59.2.2014-05
aquaculture. The sediment pH ranged from 6.2 to 8.32. The organic
carbon levels in sediment ranged from 0.27 to 2.94% indicating medium
to high productive nature of sediment. Samples of mud crab collected from
the study areas were processed for screening for WSSV infection. All
samples gave Negative results in primary as well as nested PCRs,
indicating the absence of WSSV in the wild mud crab population.
Integrating the analysis result along with supporting spatial data with the
aid of GIS and Remote Sensing techniques, a total of 10.063 ha have been
evaluated as suitable areas for mud crab farming along the brackishwater
stretches of Anjarle (1.91 ha), Aade (2.069 ha), Kelshi (1.77 ha), Velas
(0.538 ha) and Ansure (3.776 ha)
Near-Surface Interface Detection for Coal Mining Applications Using Bispectral Features and GPR
The use of ground penetrating radar (GPR) for detecting the presence of near-surface interfaces is a scenario of special interest to the underground coal mining industry. The problem is difficult to solve in practice because the radar echo from the near-surface interface is often dominated by unwanted components such as antenna crosstalk and ringing, ground-bounce effects, clutter, and severe attenuation. These nuisance components are also highly sensitive to subtle variations in ground conditions, rendering the application of standard signal pre-processing techniques such as background subtraction largely ineffective in the unsupervised case. As a solution to this detection problem, we develop a novel pattern recognition-based algorithm which utilizes a neural network to classify features derived from the bispectrum of 1D early time radar data. The binary classifier is used to decide between two key cases, namely whether an interface is within, for example, 5 cm of the surface or not. This go/no-go detection capability is highly valuable for underground coal mining operations, such as longwall mining, where the need to leave a remnant coal section is essential for geological stability. The classifier was trained and tested using real GPR data with ground truth measurements. The real data was acquired from a testbed with coal-clay, coal-shale and shale-clay interfaces, which represents a test mine site. We show that, unlike traditional second order correlation based methods such as matched filtering which can fail even in known conditions, the new method reliably allows the detection of interfaces using GPR to be applied in the near-surface region. In this work, we are not addressing the problem of depth estimation, rather confining ourselves to detecting an interface within a particular depth range
The inherent tensions within sustainable supply chains: a case study from Bangladesh
The complexities surrounding the supply chain logistics for perishable commodities within Bangladesh are extensive. Poor infrastructure, fragmented transportation and corruption compound the operational complexities within this emerging market. This case study analyses many of the day-to-day operational challenges and tensions inherent within Micro-Small-Medium Enterprises (MSMEs) forming the backbone of the Bangladesh socio-economic structure. The drive for transition toward greater levels of sustainability and corporate responsibility is problematic, affecting many levels within an extended and fragmented supply chain. The selected case study highlights the “lived in” geographical, environmental, economic and cultural factors that impact the ability of emerging market enterprises to remain profitable within emergency scenarios whilst transitioning toward a more sustainable model. This study, whilst detailing many of the tensions and critical issues facing MSMEs, highlights the benefits of direct Government intervention, criticality of a leaner and more efficient supply chain and reassessment of financial incentives to drive the transition to a more efficient and sustainable economy
Studies on Medium Grade Ilmenite-Depleted Beach Placer deposit of Chavakkad Ponnani Coast, Kerala
In the present paper, characterization, beneficiation and further value addition studies carried out with samples collected from unexploited Chavakkad ponnani (CP) area of Kerala coast have been reported. Characterization studies involve size and chemical analyses, sink and float studies and optical microscopy. total 21 samples were collected from 18 km. stretch of CP area at almost 1 km. apart. While sink and float studies and optical microscopy were carried on with all individual samples, detail characterization and beneficiation studies were undertaken with composite samples-one prepared from all 21 samples and the second from few selected samples. Pre-concentration followed by high tension separation and magnetic separation yielded product containing more than 95% THM with around 90% recovery. Further value addition studies with generated ilmenite concentrate was found to produce synthetic rutile, through reduction followed by oxidation and leaching, containing more than 94% TiO2
Changes in extreme sea-levels in the Baltic Sea
In a climate change context, changes in extreme sea-levels rather than changes in the mean are of particular interest from the coastal protection point of view. In this work, extreme sea-levels in the Baltic Sea are investigated based on daily tide gauge records for the period 1916–2005 using the annual block maxima approach. Extreme events are analysed based on the generalised extreme value distribution considering both stationary and time-varying models. The likelihood ratio test is applied to select between stationary and non-stationary models for the maxima and return values are estimated from the final model. As an independent and complementary approach, quantile regression is applied for comparison with the results from the extreme value approach. The rates of change in the uppermost quantiles are in general consistent and most pronounced for the northernmost stations
Chromosomal-level assembly of the Asian Seabass genome using long sequence reads and multi-layered scaffolding
We report here the ~670 Mb genome assembly of the Asian seabass (Lates calcarifer), a tropical marine teleost. We used long-read sequencing augmented by transcriptomics, optical and genetic mapping along with shared synteny from closely related fish species to derive a chromosome-level assembly with a contig N50 size over 1 Mb and scaffold N50 size over 25 Mb that span ~90% of the genome. The population structure of L. calcarifer species complex was analyzed by re-sequencing 61 individuals representing various regions across the species' native range. SNP analyses identified high levels of genetic diversity and confirmed earlier indications of a population stratification comprising three clades with signs of admixture apparent in the South-East Asian population. The quality of the Asian seabass genome assembly far exceeds that of any other fish species, and will serve as a new standard for fish genomics
Glimpses of biodiversity in the Kadalundi-Vallikunnu Community Reserve, the first Community Reserve of Kerala
Biodiversity is the mainstay of ecosystem services and functions
and supports the livelihood of millions of people. Sustainable
utilization and conservation of our rich biological diversity is a prerequisite
for human survival. India is a megadiverse country and with
only 2.4% of the world’s geographical area, it accounts for 7 to 8% of all
recorded species. Our country is a signatory to various international
instruments focussing on matters of biodiversity, including the
Convention on Biological Diversity (CBD). The country has an obligation
to protect our rich biological diversity and is one of the leaders in having
established a comprehensive legal and institutional system to achieve
the objectives of the CBD. Expansion of India’s Protected Area (PA)
network, including ‘Conservation and Community Reserves’ is one of
the important action points of the National Biodiversity Action Plan of
our country.
The Kadalundi-Vallikunnu Community Reserve which lies in the
Malabar region is the first Community Reserve of Kerala and is known
for its rich biological diversity. Endowed with dense mangrove forests
and mudflats, the Community Reserve is an abode to a large number
of avian fauna, including many migratory species. Fishing and ecotourism
have been the mainstay of income generation for many local
inhabitants of the Community Reserve. Considering the ecological
significance, diversity of wetland avian fauna and the burden of heavy
anthropogenic pressures, the Kadalundi estuary was officially declared
as the ‘Kadalundi-Vallikunnu Community Reserve’ in October, 2007. Bio-inventorying and documentation of biodiversity is invaluable
for the wise use of our ecosystems and the sustainability of biological
resources. This publication is an outcome of a detailed study
conducted by the ICAR-Central Marine Fisheries Research Institute in
collaboration with the Kerala State Biodiversity Board to document the
rich biodiversity of the Kadalundi-Vallikunnu Community Reserve and
to assess the economic value of the various ecosystem services rendered
by the Community Reserve. The publication provides an insight in to
the diversity of plankton, seagrass, mangroves, mangrove associates,
avian fauna, molluscs, crustaceans and finfishes of the Community
Reserve with an overview of the economic value of the ecosystem
services. The various threats faced by the Community Reserve and
meaningful options for the conservation and sustainable management
of the Reserve is also highlighted in this document
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