513 research outputs found
Identification and evaluation of ecosystem services provided by clam (Villorita cyprinoides) fisheries in wetland
Black clam (Villorita cyprinoides), constitute a major molluscan based subsistence level fishery in Vembanadlake providing a variety of ecosystem services to the dependent populations of the ecosystem. The non-realization of the values of the services provided by clams coupled with the anthropogenic activities like dredging aggravated the non-sustainable harvest of the resource. The paper attempts to evaluate the provisioning and cultural services provided by clams in-order to highlight the importance of the management of this ecosystem service provider and various tradeoffs between anthropogenic activities and clam resource utilizations
Evaluation of Ecosystem services of Villorita cyprinoides in Vembanad
Vembanad Lake, a wetland of international importance, famous for waterfowl habitat was designated a
Ramsar site, for conservation and sustainable utilisation of the ecosystem. Millennium ecosystem assessment
(2005) emphasises that the various services provided by the ecosystem benefitting human population needs to be
identified and evaluated for judicious utilisation of the resources. Villorita cyprinoides is a major species
contributing to the molluscan fishery of Vembanad lake. The study involving Villorita sp. was taken up with the
objectives of development of a conceptual framework encompassing the different ecosystem services provided by
the clam resources, estimation of the values of selected ecosystem services using appropriate proxies and
analysis of the trade-offs between anthropogenic activities like dredging vis-a-vis clam resources utilizations
following the principles of MEA (2005). The study identified that the clam fisheries in the lake is most
acknowledged for its provisioning ecosystem services. Apart from the regulating services such as water quality
maintenance and carbon sequestration, the cultural and the linking services provided by clam fisheries to
human are also identified. In spite of the identification of the various services, the non-realisation of the value of
the services provided by clam fisheries has prompted the destruction of the resource knowingly or unknowingly
by our activities. One of the anthropogenic activities affecting the clam fisheries is the dredging of sub fossil
deposits of clamshell or white clams which are good sources of calcium carbonate for cement manufacturers.
Identifying the lacunae of non-realisation of the services of clam resources, the paper has judiciously attempted
not only to evaluate the services of the ecosystem service provider but also to externalize the internalities in the
ecosystem services evaluation process by considering the various social costs and benefits associated with the
resource
Biochemistry and Molecular Biology Developmentally Regulated Production of meso- Zeaxanthin in Chicken Retinal Pigment Epithelium/ Choroid and Retina
PURPOSE. meso-Zeaxanthin is a carotenoid that is rarely encountered in nature outside of the vertebrate eye. It is not a constituent of a normal human diet, yet this carotenoid comprises onethird of the primate macular pigment. In the current study, we undertook a systematic approach to biochemically characterize the production of meso-zeaxanthin in the vertebrate eye. METHODS. Fertilized White Leghorn chicken eggs were analyzed for the presence of carotenoids during development. Yolk, liver, brain, serum, retina, and RPE/choroid were isolated, and carotenoids were extracted. The samples were analyzed on C-30 or chiral HPLC columns to determine the carotenoid composition. RESULTS. Lutein and zeaxanthin were found in all studied nonocular tissues, but no mesozeaxanthin was ever detected. Among the ocular tissues, the presence of meso-zeaxanthin was consistently observed starting at embryonic day 17 (E17) in the RPE/choroid, several days before its consistent detection in the retina. If RPE/choroid of an embryo was devoid of mesozeaxanthin, the corresponding retina was always negative as well. CONCLUSIONS. This is the first report of developmentally regulated synthesis of mesozeaxanthin in a vertebrate system. Our observations suggest that the RPE/choroid is the primary site of meso-zeaxanthin synthesis. Identification of meso-zeaxanthin isomerase enzyme in the developing chicken embryo will facilitate our ability to determine the biochemical mechanisms responsible for production of this unique carotenoid in other higher vertebrates, such as humans
In-orbit Performance of UVIT on ASTROSAT
We present the in-orbit performance and the first results from the
ultra-violet Imaging telescope (UVIT) on ASTROSAT. UVIT consists of two
identical 38cm coaligned telescopes, one for the FUV channel (130-180nm) and
the other for the NUV (200-300nm) and VIS (320-550nm) channels, with a field of
view of 28 . The FUV and the NUV detectors are operated in the high
gain photon counting mode whereas the VIS detector is operated in the low gain
integration mode. The FUV and NUV channels have filters and gratings, whereas
the VIS channel has filters. The ASTROSAT was launched on 28th September 2015.
The performance verification of UVIT was carried out after the opening of the
UVIT doors on 30th November 2015, till the end of March 2016 within the
allotted time of 50 days for calibration. All the on-board systems were found
to be working satisfactorily. During the PV phase, the UVIT observed several
calibration sources to characterise the instrument and a few objects to
demonstrate the capability of the UVIT. The resolution of the UVIT was found to
be about 1.4 - 1.7 in the FUV and NUV. The sensitivity in various
filters were calibrated using standard stars (white dwarfs), to estimate the
zero-point magnitudes as well as the flux conversion factor. The gratings were
also calibrated to estimate their resolution as well as effective area. The
sensitivity of the filters were found to be reduced up to 15\% with respect to
the ground calibrations. The sensitivity variation is monitored on a monthly
basis. UVIT is all set to roll out science results with its imaging capability
with good resolution and large field of view, capability to sample the UV
spectral region using different filters and capability to perform variability
studies in the UV.Comment: 10 pages, To appear in SPIE conference proceedings, SPIE conference
paper, 201
Length-weight relationship and condition factor of Dawkinsia filamentosa (Valenciennes, 1844) in different aquatic habitats
The growth rate of a species in any aquatic environment is an indicator of
the water quality of the system. In the current study, the Length-weight
relationship (LWR) and the condition factor of Dawkinsia filamentosa from
various aquatic ecosystems especially lotic, lentic and brackish lentic
systems were compared. It was observed that growth rate of the fish was
more in brackish lentic systems. The study showed that already reported
growth rate (b) of the species in brackish lentic systems is around 3.273
indicating proximity towards the isometric growth pattern as compared to
the growth rate in reservoirs (2.3184) and that in lentic systems
(3.116) obtained from present study. Similar studies supplemented with
environmental variables can be used to study the health status of the
ecosystem. The best system suitable for the adaptive growth of the
species can be ascertained only after a holistic approach involving
environmental variables
Customizing hybrid products
We explore how the convergence of the digital and physical into hybrid products leads to new possibilities for customization. We report on a technology probe, a hybrid advent calendar with both paper form and digital layers of content, both of which were designed to be customizable. We reveal how over two hundred active users adapted its physical and digital aspects in various ways, some anticipated and familiar, but others surprising. This leads us to contribute concepts to help understand and design for hybrid customization – the idea of broad customization spanning physical and digital; end-to-end customization by different stakeholders along the value chain for a product; and the combination of these into customization maps
Evaluation of the performance of high phosphorous with germanium codoped multimode optical fiber for use as a radiation sensor at low dose rates
We propose a GeO(2)-P(2)O(5)-codoped step index multimode (SIMM) fiber having a core diameter of around 50 mu m with numerical aperture of around 0.21-0.22. The proposed SIMM fiber shows excellent linear radiation response behavior with sensitivity of around 0.69-0.97 dB/m/100 rad at a 505 nm wavelength within the dose rate range of 10-100 rad/h, as well as very low recovery at room temperature using a (60)Co gamma radiation source. This enables its practical application in fiber optic personal dosimeters for measurement of low dose gamma radiation. (C) 2011 Optical Society of Americ
‘It Takes Two Hands to Clap’: How Gaddi Shepherds in the Indian Himalayas Negotiate Access to Grazing
This article examines the effects of state intervention on the workings of informal institutions that coordinate the communal use and management of natural resources. Specifically it focuses on the case of the nomadic Gaddi
shepherds and official attempts to regulate their access to grazing pastures in the Indian Himalayas. It is often predicted that the increased presence of the modern state critically undermines locally appropriate and community-based resource management arrangements. Drawing on the work of Pauline Peters and Francis Cleaver, I identify key instances of socially embedded ‘common’ management institutions and explain the evolution of these arrangements
through dynamic interactions between individuals, communities and the agents of the state. Through describing the ‘living space’ of Gaddi shepherds across the annual cycle of nomadic migration with their flocks I explore the
ways in which they have been able to creatively reinterpret external interventions, and suggest how contemporary arrangements for accessing pasture at different moments of the annual cycle involve complex combinations of the
formal and the informal, the ‘traditional’ and the ‘modern’
Production of Lambda and Sigma^0 hyperons in proton-proton collisions
This paper reports results on simultaneous measurements of the reaction
channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239,
and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and
differential cross sections are given for both reactions. It is concluded from
the measured total cross sections that the high energy limit of the cross
section ratio is almost reached at an excess energy of only about 200 MeV. From
the differential distributions observed in the overall CMS as well as in the
Jackson and helicity frames, a significant contribution of interfering nucleon
resonances to the \Lambda production mechanism is concluded while resonant
\Sigma^0-production seems to be of lesser importance and takes place only
through specific partial waves of the entrance channel. The data also indicate
that kaon exchange plays a minor role in the case of \Lambda- but an important
role for \Sigma^0-production. Thus the peculiar energy dependence of the
\Lambda-to-\Sigma^0 cross section ratio appears in a new light as its
explanation requires more than mere differences between the p\Lambda and the
p\Sigma^0 final state interaction. The data provide a benchmark for theoretical
models already available or yet to come.Comment: 18 pages, 10 figures; accepted by The European Physical Journal A
(EPJ A
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