1,945 research outputs found
Groundwater governance in the Indo-Gangetic Basin: interplay of hydrology and socio-ecology in India. Abstract only
Groundwater irrigationGovernanceRiver basinsWellsTube wellsPumpingEnergy consumptionCosts
Assessing institutional and environmental parameters of agricultural water use in South Asia: evidences from the Indo-Gangetic Basin
River basins / Irrigation water / Water use / Economic aspects / Environmental effects / Corporate culture / Valuation / Case studies / Water market / Wells / South Asia
Tentative Appraisal of Compatibility of Small-Scale CMB Anisotropy Detections in the Context of COBE-DMR-Normalized Open and Flat CDM Cosmogonies
Goodness-of-fit statistics are used to quantitatively establish the
compatibility of CMB anisotropy predictions in a wide range of DMR-normalized,
open and spatially-flat , CDM cosmogonies with the set of all
presently available small-scale CMB anisotropy detection data. Conclusions
regarding model viability depend sensitively on the prescription used to
account for the 1 uncertainty in the assumed value of the DMR
normalization, except for low-density, -- 0.4, open models
which are compatible with the data for all prescriptions used. While large
baryon-density (\Omega_B \gap 0.0175 h^{-2}), old (t_0 \gap 15 -- 16 Gyr),
low-density ( -- 0.4), flat- models might be
incompatible, no model is incompatible with the data for all prescriptions. In
fact, some open models seem to fit the data better than should be expected, and
this might be an indication that some error bars are mildly overconservative.Comment: 15 page PostScript file, including 6 included figures. Also available
via anonymous ftp from ftp://astro.caltech.edu/users/kmg/chi.p
Valuating agricultural water use and ecological services in agrarian economies: evidences from eastern India
Irrigation water / Water use / Economic aspects / Valuation / Land ownership / India
Economic effects of water use and landholding scale to farming in South Asia: evidences from Indo-Gangetic basin
Agricultural development / Irrigation water / Water use / Water allocation / Land ownership / Economic aspects / River basins / Models / South Asia / Indo-Gangetic Basin
Understanding and managing the water-energy nexus: Moving beyond the energy debate
Groundwater irrigationEnergy
Environmental services and agricultural water in South Asia: evidence from Indo-Gangetic Basin
Irrigation water / Water use / River basins / Environmental effects / Models / South Asia / India / Pakistan / Nepal / Indo-Gangetic Basin
Window Function for Non-Circular Beam CMB Anisotropy Experiment
We develop computationally rapid methods to compute the window function for a
cosmic microwave background anisotropy experiment with a non-circular beam
which scans over large angles on the sky. To concretely illustrate these
methods we compute the window function for the Python V experiment which scans
over large angles on the sky with an elliptical Gaussian beam.Comment: 27 pages, 5 figure
Advances in Raman hyperspectral compressive detection instrumentation for fast label free classification, quantitation and imaging
Multiple prototypes of hyperspectral compressive detection (CD) Raman spectrometers have previously been constructed in the Ben-Amotz lab and have proven to be useful for fast, label-free chemical identification, quantitation and imaging. The CD spectrometer consists of a volume holographic grating (VHG) that linearly disperses the Raman photons into its component wavelengths and all wavelengths are focused onto a digital micromirror devise (DMD). The DMD is an optical modulator that consists of an array of programmable 10μm mirrors that can reflect photons in either +12° or -12° to the incoming light. The DMD is tilted such that the +12° photons go back through the focusing lens and the VHG and is focused onto a single 150μm photon counting avalanche photodiode detector(APD).
In chapter 1 of the thesis I describe the construction of a new CD Raman spectrometer capable of fast hyperspectral imaging that has better photon collection efficiency and fewer photon losses compared to its predecessors. The new spectrometer consists of a VHG and a DMD, however, the DMD is not tilted but is perpendicular to the incoming Raman photons. All the Raman photons modulated by the DMD are symmetrically detected in the +12° and -12° by two photon counting photomultiplier tube(PMT) detector modules. The new spectrometer avoids a double pass through the optics and hence has fewer losses associated due to reflection transmission of the optics. Full spectral measurements are made by consecutively scanning through columns of the DMD mirrors and measuring the intensity of photons associated with each wavelength. CD measurements are made by multiplexing wavelengths channels onto the detectors and can be done by applying optimal binary(OB) or Hadamard filters. The new optical design has a spectral window from 150cm-1 to 4000 cm-1 and the improvement in the photon collection efficiency allows classification and imaging speeds of 10μs per point with 13mW of laser power on the sample, and is significantly faster than measurements made with the previous prototype.
In chapter 2 of the thesis I describe the construction of a new instrument which is equipped with both a hyperspectral CD spectrometer as well as a traditional Czerny Turner spectrometer. A flip mirror after the Raman microscope directs the Raman scattered beam either towards the CD spectrometer (with the mirror down) or towards the Czerny Turner spectrometer. This instrument allows us to perform head to head comparisons of the two spectrometers using the same Raman scattered photons emitted by the sample. The CD spectrometer uses hardware optical filters to perform compressed chemometric measurements to classify chemicals. The traditional spectrometer uses the CCD to measure full spectral data and chemometric analysis is performed to extract lower dimensional chemical information post measurement. Chemical classification results obtained using two sets of chemicals with differing degrees of spectral overlap show that CD classification is comparable to full spectral classification in the high signal regime. However, for signals consisting of less than 1000 total photon counts, CD classification outperforms full spectral classification.
In chapter 3 of the thesis, Raman spectroscopy is used to probe changes in vibrational spectra of nucleotide solutions and hanging droplets containing RNA crystals at different pH. Self-modeling curve resolution (SMCR) applied to full Raman is used to extract solute correlated (SC) Raman spectral components that contain solute spectra with minimal interference from the surrounding solvent. The goal of these studies is to show that Raman spectroscopy can be used to study biological molecules in aqueous environments, with minimal sample preparation and without the need of labels
Are there any ‘hot’ spots and ‘bright’ spots of rice water productivity in Bangladesh? A spatio-temporal analysis of district-level data
Employing Bangladeshi district-level time series data as an empirical exploration this paper aims to: (1) estimate two measures of rice water productivity for the main crop seasons; (2) undertake a spatio-temporal analysis; and (3) identify ‘hot’ spots and ‘bright’ spots focusing on the Ganges-dependent (GDA) vis-à-vis other districts (NGDA). The paper finds that (1) kharif (wet) season rice water productivity grew much faster than for the rabi (dry) season across all districts. There was no significant correlation between seasonal growth rates although significant correlation existed between seasonal growth rates and the annual growth rate. Eight Ganges dependent districts experienced faster growth rate in kharif and overall productivity but their rabi season performance was slower relative to other districts. (2) Marginal productivity (MP) experienced fastest growth for the kharif season during 1968-1980. Up to 1990, there was no significant growth in rabi MP. Its growth declined in the 1980s but picked up since the early 1990s. (3) MPs products were slightly lower in the GDA districts for kharif and overall. The study did not find any consistent ‘hot’ spots or ‘bright’ spots in Bangladeshi rice water productivity. The process is highly groundwater intensive and is debatable whether it is sustainable.
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