27 research outputs found

    Spin-Polarized Transport Across an La0.7_{0.7}Sr0.3_{0.3}MnO3_{3}/YBa2_{2}Cu3_{3}O7_{7} Interface: Role of Andreev Bound States

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    Transport across an La0.7_{0.7}Sr0.3MnO_{0.3}MnO_{3}/YBa2Cu_{2}Cu_{3}OO_{7}(LSMO/YBCO),interfaceisstudiedasafunctionoftemperatureandsurfacemorphology.Forcomparison,controlmeasurementsareperformedinnon−magneticheterostructuresofLaNiO(LSMO/YBCO), interface is studied as a function of temperature and surface morphology. For comparison, control measurements are performed in non-magnetic heterostructures of LaNiO_{3}$/YBCO and Ag/YBCO. In all cases, YBCO is used as bottom layer to eliminate the channel resistance and to minimize thermal effects. The observed differential conductance re ects the role of Andreev bound states in a-b planes, and brings out for the first time the suppression of such states by the spin-polarized transport across the interface. The theoretical analysis of the measured data reveals decay of the spin polarization near the LSMO surface with temperature, consistent with the reported photoemission data.Comment: 5 pages LaTeX, 3 eps figures included, accepted by Physical Review

    Vegetation dynamics under different management interventions in arid rangelands of Rajasthan

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    Watershed rangelands in Northern Afghanistan provide various ecosystem services that support the local people’s livelihoods, but they are now highly degraded essentially due to the continuous high grazing pressure and recurrent droughts. Effects of shrub establishment method enhanced by water harvesting techniques to rehabilitate degraded rangelands have not been well addressed. The main goal of this study was to evaluate the impact of direct seeding and transplanting of seedlings in combination with semi-circular bunds on growth, yield, and survival rate of four shrub species (Atriplex halimus, Atriplex nummularia, Atriplex lentiformis, and Maireana brevifolia) under semi- arid conditions of Sayyad village, Khulm watershed. Survival rate (%), plant height, width, and plant length (cm) and plant cover (%) were measured for each plant over five occasions. A non-destructive reference unit was used to estimate biomass production. The results showed that growth attributes and biomass production of shrubs were consistently greater in the transplanting compared to direct seeding. On average, the plant length, width, height, volume, cover, and biomass production of transplanted shrubs were greater than direct-seeded shrubs by 24.3%, 8.6%, 8.7%, 121.5%, 13.8% and 34.1%, respectively. Biomass production of transplanted seedlings was the highest for A. nummularia (1313.5 g DM/plant) and A. halimus (800 g DM/plant). There was a strong correlation between plant biomass production and plant volume (R2 Plant volume = 0.88) for the shrub A. nummularia, indicating that plant volume is a key variable for assessing biomass production for this species. Additionally, the survival rate of M. brevifolia was 100% in both planting methods, suggesting that based on better survival this halophytic plant has great potential when restoring degraded rangelands

    First report of Protoperidinium steinii (Dinophyceae) bloom from the coastal marine ecosystem - an observation from tropical Indian waters

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    A dense bloom of Protoperidinium steinii was observed in the backwaters adjoining the western Bay of Bengal, Kalpakkam coast, which might be the first report for the world oceans. The brownish-red bloom appeared on 2 October 2019, and it was monitored on alternate days up to 14 October. Surface water temperature was about 27.5°C and salinity was <17 PSU during the bloom. Dissolved inorganic nutrients like nitrate, ammonia, silicate, and phosphate were extremely high compared to that of the coastal waters. The chlorophyll-a maxima (20.95 mg m−3) coincided with the highest Protoperidinium density (113.9 × 104 cells l −1). The contribution of P. steinii ranged from 17−93% of the total phytoplankton population. Since P. steinii is a heterotroph and voracious grazer, low autotroph density was observed during the bloom. No mass mortality of fish or other organisms was observed, thereby indicating the nontoxic nature of the bloo
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