Through the release of groundwater, most mountain rivers run year‐round despite their small catchments and sporadic precipitation. This makes mountain ranges important sources of reliable freshwater ...for downstream populations in many parts of the world. However, due to a lack of ground instrumentation, little is known about groundwater dynamics in mountainous landscapes. Recent research has shown that the amount of moisture trapped in the soil and weathered rocks in the vadose zone can significantly buffer groundwater recharge and runoff but the wider recognition of this effect on major mountain systems has not been yet established. In this study, we test whether the moisture reservoir has an impact on hydrological fluxes in a steep Himalayan catchment during three monsoon seasons. We measured an array of parameters including relative seismic velocity changes from ambient noise correlations. This noninvasive technique allows us to monitor groundwater dynamics in conjunction with classical hydrological measurements. We found that the moisture saturation in the vadose zone controls the onset of groundwater recharge and runoff and therefore determines the annual water availability supplied by monsoon precipitation. We model this dynamic using a surface layer that has a finite storage capacity that controls the connectivity of surface flux to groundwater. The extension of this concept, which is thought to apply widely in flat and undulating landscapes, to steep mountain topography with thin and discontinuous soils underlain by regolith and bedrock has important implications for mountain hydrology.
Plain Language Summary
The Nepal Himalayas supply essential water resources to a large part of the population of South Asia. Most of this water drains through a mountain groundwater reservoir that is poorly constrained. In steep landscapes, this reservoir is continuously losing water due to gravitational pull. Understanding how the reservoir fills and drains is crucial to the assessment of its sustainability and projection into the future with respect to global climate change. However, the relevant subsurface processes are generally challenging to observe due to limited access to the subsurface, particularly in steep mountain landscapes. We have used seismic ambient noise, ground vibrations continuously recorded by seismometers, to monitor the groundwater dynamics on a spatially integrated scale in a Himalayan valley. We show that the moisture content of a shallow layer controls the transfer of precipitation into the deeper groundwater reservoir during the Indian monsoon seasons. Our study highlights the need to anticipate the effects of changes of land use, soil cover conditions and rainfall regime, due to climate change, to better predict the future of freshwater resources in mountain landscapes.
Key Points
Passive seismic interferometry reveals detailed insights into subsurface water storage variability in the Nepal Himalayas
Vadose zone moisture saturation controls river discharge generation in a steep mountain landscape
Freshwater delivery from high mountains is strongly dependent on subsurface conditions, which are rarely considered in these environments
Nanofibers of cobalt manganese oxide (CoMn2O4) were grown using an electrospun technique. Structural and microstructural characterizations confirm the formation of phase pure CoMn2O4 with high ...porosity. The potential application of CoMn2O4 nanofibers as an electrode material for energy storage device was studied using cyclic voltammetry and galvanostatic charge-discharge measurements. A specific capacitance of 121 F/g was observed with enhanced cyclic stability. Furthermore, an energy storage device was fabricated by sandwiching two electrodes separated by an ion transporting layer. The device showed a specific capacitance of 241 mF/cm2 in 3 M NaOH electrolyte. The effect of temperature on the charge storage properties of the device was also investigated for high temperature applications. The device showed about 75% improvement in the charge storage capacity when the temperature was increased from 10 to 70 °C. This research suggests that nanofibers of CoMn2O4 could be used for fabrication of energy storage devices which could operate in a wide temperature range with improved efficiency.
•Nanofibers of CoMn2O4 were fabricated using electrospun method.•A specific capacitance of 121 F/g was observed with enhanced cyclic stability.•A supercapacitor device showed a specific capacitance of 241 mF/cm2.•The device showed 75% improvement in charge storage on increasing temperature from 10 to 70 °C.
Amino acids (AAs) play significant roles in metal binding, antioxidant defense, and signaling in plants during heavy metal stress. In the present study, the essential amino acids (EAAs), ...non-essential amino acids (NEAAs), as well as the enzymes of proline and cysteine biosynthetic pathways were studied in contrasting arsenic accumulating rice genotypes grown in hydroponic solutions with addition of arsenate (Asⱽ) or arsenite (Asᴵᴵᴵ). Under a mild As stress, the total AAs content significantly increased in both the rice genotypes with a greater increase in a low As accumulating rice genotype (LAARG; IET-19226) than in a high As accumulating rice genotype (HAARG; BRG-12). At the equimolar concentration (10 μM), Asᴵᴵᴵ had a greater effect on EAAs than Asⱽ. Conversely, Asⱽ was more effective in inducing a proline accumulation than Asᴵᴵᴵ. Among NEAAs, As significantly induced the accumulation of histidine, aspartic acid, and serine. In contrast, a higher As concentration (50 μM) reduced the content of most AAs, the effect being more prominent during Asᴵᴵᴵ exposure. The inhibition of glutamate kinase activity was noticed in HAARG, conversely, serine acetyltransferase and cysteine synthase activities were increased which was positively correlated with the cysteine synthesis.
Simulated pot experiments were conducted on four rice (Oryza sativa L.) genotypes (Triguna, IR-36, PNR-519, and IET-4786) to examine the effects of As(V) on amino acids and mineral nutrient status in ...grain along with antioxidant response to arsenic exposure. Rice genotypes responded differentially to As(V) exposure in terms of amino acids and antioxidant profiles. Total amino acid content in grains of all rice genotypes was positively correlated with arsenic accumulation. While, most of the essential amino acids increased in all cultivars except IR-36, glutamic acid and glycine increased in IET-4786 and PNR-519. The level of nonprotein thiols (NPTs) and the activities of superoxide dismutase (SOD; EC 1.15.1.1), glutathione reductase (GR; EC 1.6.4.2) and ascorbate peroxidase (APX; EC 1.11.1.11) increased in all rice cultivars except IET-4786. A significant genotypic variation was also observed in specific arsenic uptake (SAU; mg kg(-1)dw), which was in the order of Triguna (134) > IR-36 (71) > PNR-519 (53) > IET-4786 (29). Further, application of As(V) at lower doses (4 and 8 mg L(-1) As) enhanced the accumulation of selenium (Se) and other nutrients (Fe, P, Zn, and S), however, higher dose (12 mg L(-1) As) limits the nutrient uptake in rice. In conclusion, low As accumulating genotype, IET-4786, which also had significantly induced level of essential amino acids, seems suitable for cultivation in moderately As contaminated soil and would be safe for human consumption.
Moyna of Purba Medinipur district is widely known as an aquaculture hub of West Bengal, India. Though very good production is achievable from this fish culture system, management practices are ...inappropriate, which could create the sustainability problem of this culture system. The present study was thus undertaken for the estimation of plankton population, water quality, carbon footprint and carbon sequestration of this intensive aquaculture practices. Information on spawn to fry, fry to fingerlings and grow-out culture were collected through the structured questionnaire from the fish farmers. The plankton density, primary productivity, carbon footprint and carbon sequestration were analyzed using standard procedures. The phytoplankton, zooplankton and primary productivity were maximum at the stocking period and minimum during the middle of culture period. The lowest feed conversion ratio (FCR) was noticed with the minimum amount of feed applied in the pond. The CO
2
-e emission ranged from 0.56 to 4.89 kg CO
2
-e/kg fish (av. 2.13) for the production levels of 5.0 to 10.7 t/ha/yr. The pond water developed salinity and ammonium-N increased from 0.01 to 0.50 mg/l. The ponds with high feed loading (28 to 32 t/ha/yr) had the highest average sediment accumulation rate (11.0 ± 3.0 cm/yr) and carbon sequestration (704 ± 30 g C/m
2
/yr).
Classifying land use/land cover (LULC) with sufficient accuracy in heterogeneous landscapes is challenging using only satellite imagery. To improve classification accuracy inclusion of features from ...auxiliary geospatial datasets in classification models is applied since 1980s. However, the method is mostly limited to pixel-based classifications, and the coverage, accuracy and resolution of free and open-access auxiliary datasets have been poor until recent years.
We evaluated how recent global coverage open-access geospatial datasets improve object-based LULC classification accuracy compared to using only spectral and texture features from satellite images. We applied feature sets topography, population, soil, canopy cover, distance to watercourses and spectral-temporal metrics from Landsat-8 time series on the southern foothills and savanna of Mt. Kilimanjaro, Tanzania, where the landscape is characterized by heterogeneous and fragmented mosaic of disturbed savanna vegetation, croplands, and settlements.
The classification was based on image objects (groups of spectrally similar pixels) derived from segmentation of four Formosat-2 scenes with 8 m spatial resolution using 1370 ground reference points for training, validation, and for defining 17 LULC classes. We built six Random Forest classification models with different sets of object features in each. The baseline model having only spectral and texture features was compared with five other models supplemented with auxiliary features.
Inclusion of auxiliary features significantly improved classification overall accuracy (OA). The baseline model gave a median OA of 60.7%, but auxiliary features in other models increased median OA between 6.1 and 16.5 percentage points. The best OA was achieved with a model including all features of which elevation was the most important auxiliary feature followed by Enhanced Vegetation Index temporal range and slope degree.
Applying object-based classification to geospatial information on topography, soil, settlement patterns and vegetation phenology, the discriminatory potential of challenging LULC classes can be significantly improved. We demonstrated this for the first time, and the technique shows good potential for improving LULC mapping across a multitude of fragmented landscapes worldwide.
•Auxiliary open datasets were evaluated for improving object-based land cover mapping.•Six random forest models with and without auxiliary features were compared.•Including auxiliary features significantly improved classification overall accuracy.•Topographic and spectral-temporal metrics were most important.•Open datasets are valuable data source for mapping heterogeneous savanna landscapes.
We report here the studies on third-order nonlinear optical properties of two novel polythiophene composite films investigated using the Z-scan technique. The measurements were carried out using a ...Q-switched, frequency doubled Nd:YAG laser producing 7 nanosecond laser pulses at 532 nm. Z-scan results reveal that the composite films exhibit self-defocusing nonlinearity. The real and imaginary parts of the third-order nonlinear optical susceptibility were of the order 10
−12
esu. The effective excited-state absorption cross section was found to be larger than the ground state absorption cross section, indicating that the operating nonlinear mechanism is reverse saturable absorption (RSA). The polythiophene composite films also exhibit good optical power limiting of the nanosecond laser pulses. The nonlinear optical parameters are found to increase on increasing the strength of the electron-donor group, indicating the dependence of
χ
(3)
on the electron-donor/acceptor units of polythiophenes.
Abstract
Kali-Gandaki “A” is a medium head Francis turbine site located in Syangja District of Nepal. The dimensionless specific speed number for this site falls in the range suitable for generating ...meridional profile from Bovet Method. In this paper, the meridional profile of the actual runner currently deployed is extracted from CAD drawings and another meridional profile is generated using empirical relations of the Bovet Method. Meridional area of profile from Bovet Method is significantly larger in comparison to CAD-based profile. Both of these profiles are imported in commercial software ANSYS BLADEGEN, using linear blade angle distribution with no lean runner’s 3D model is generated for both cases. Both designs are meshed in Turbo-Grid and simulated in ANSYS CFX with k-epsilon turbulence model. Simulation reveals the CAD-based runner has 91.11% efficiency in comparison to Bovet based runner which has only 85.6% efficiency. Also, Simulation results reveal Bovet-based runner is more susceptible towards erosion and cavitation which suggests there is room for improvement and optimization of design obtained from Bovet Method.
Micronutrient deficiencies during pregnancy may be linked to poor newborn health and poor host defences against infection. We assessed newborn morbidity to determine the effect of four combinations ...of antenatal micronutrient supplements.
Cluster-randomised, double-masked, controlled trial.
Rural community in Nepal.
Women received daily supplements from early pregnancy through to 3 months postpartum of vitamin A alone (control) or vitamin A with folic acid, folic acid plus iron, folic acid plus iron plus zinc or a multiple micronutrient supplement containing these and 11 other nutrients.
Infants were visited in their home at birth (n = 3927) and for each of 9 days thereafter to elicit a 24-h history of nine infant morbidity symptoms, measure infant respiratory rate and axial temperature, and assess the infant for chest indrawing. At 6 weeks of age, infants were visited again in their homes to elicit a 30-day and 7-day history of 10 morbidity symptoms using parental recall.
Maternal micronutrient supplementation had no effect on 10-day morbidity or morbidity 30-day and 7-day morbidity assessed at 6 weeks of age all relative risks were close to 1. Symptoms of birth asphyxia increased by about 60% (p<0.05) in infants of women who received the multiple micronutrient supplement compared with the control. Symptoms of combinations of sepsis, preterm and birth asphyxia were associated with 8- to 14-fold increased odds of 6-month infant mortality.
None of the combinations of antenatal micronutrient supplements tested improved symptoms of neonatal morbidity in the first 10 days of life or at 6 weeks of age. Further research is needed to elucidate the association and mechanism of increased risk of birth asphyxia following maternal multiple micronutrient supplementation.
NCT00115271.
The exposure of paddy fields to arsenic (As) through groundwater irrigation is a serious concern that may not only lead to As accumulation to unacceptable levels but also interfere with mineral ...nutrients in rice grains. In the present field study, profiling of the mineral nutrients (iron (Fe), phosphorous, zinc, and selenium (Se)) was done in various rice genotypes with respect to As accumulation. A significant genotypic variation was observed in elemental retention on root Fe plaque and their accumulation in various plant parts including grains, specific As uptake (29-167 mg kg⁻¹ dw), as well as As transfer factor (4-45%). Grains retained the least level of As (0.7-3%) with inorganic As species being the dominant forms, while organic As species, viz., dimethylarsinic acid and monomethylarsonic acid, were non-detectable. In all tested varieties, the level of Se was low (0.05-0.12 mg kg⁻¹ dw), whereas that of As was high (0.4-1.68 mg kg⁻¹ dw), considering their safe/recommended daily intake limits, which may not warrant their human consumption. Hence, their utilization may increase the risk of arsenicosis, when grown in As-contaminated areas.
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