927 research outputs found

    Experimental Realization of Quantum-Resonance Ratchets

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    Quantum-resonance ratchets associated with the periodically kicked particle are experimentally realized for the first time. This is achieved by using a Bose-Einstein condensate exposed to a pulsed standing light wave and prepared in an initial state differing from the usual plane wave. Both the standing-wave potential and the initial state have a point symmetry around some center and the ratchet arises from the non-coincidence of the two centers. The dependence of the directed quantum transport on the quasimomentum is studied. A detailed theoretical analysis is used to explain the experimental results.Comment: Accepted for publication in Physical Review Letters (November 2007

    Evaluation of rice–legume–rice cropping system on grain yield, nutrient uptake, nitrogen fixation, and chemical, physical, and biological properties of soil

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    To achieve higher yields and better soil quality under rice–legume–rice (RLR) rotation in a rainfed production system, we formulated integrated nutrient management (INM) comprised of Azospirillum (Azo), Rhizobium (Rh), and phosphate-solubilizing bacteria (PSB) with phosphate rock (PR), compost, and muriate of potash (MOP). Performance of bacterial bioinoculants was evaluated by determining grain yield, nitrogenase activity, uptake and balance of N, P, and Zn, changes in water stability and distribution of soil aggregates, soil organic C and pH, fungal/bacterial biomass C ratio, casting activities of earthworms, and bacterial community composition using denaturing gradient gel electrophoresis (DGGE) fingerprinting. The performance comparison was made against the prevailing farmers’ nutrient management practices [N/P2O5/K2O at 40:20:20 kg ha−1 for rice and 20:30:20 kg ha−1 for legume as urea/single super-phosphate/MOP (urea/SSP/MOP)]. Cumulative grain yields of crops increased by 7–16% per RLR rotation and removal of N and P by six crops of 2 years rotation increased significantly (P < 0.05) in bacterial bioinoculants-based INM plots over that in compost alone or urea/SSP/MOP plots. Apparent loss of soil total N and P at 0–15 cm soil depth was minimum and apparent N gain at 15–30 cm depth was maximum in Azo/Rh plus PSB dual INM plots. Zinc uptake by rice crop and diethylenetriaminepentaacetate-extractable Zn content in soil increased significantly (P < 0.05) in bacterial bioinoculants-based INM plots compared to other nutrient management plots. Total organic C content in soil declined at 0–15 cm depth and increased at 15–30 cm depth in all nutrient management plots after a 2-year crop cycle; however, bacterial bioinoculants-based INM plots showed minimum loss and maximum gain of total organic C content in the corresponding soil depths. Water-stable aggregation and distribution of soil aggregates in 53–250- and 250–2,000 μm classes increased significantly (P < 0.05) in bacterial bioinoculants-based INM plots compared to other nutrient management plots. Fungal/bacterial biomass C ratio seems to be a more reliable indicator of C and N dynamics in acidic soils than total microbial biomass C. Compost alone or Azo/Rh plus PSB dual INM plots showed significantly (P < 0.05) higher numbers of earthworms’ casts compared to urea/SSP/MOP alone and bacterial bioinoculants with urea or SSP-applied plots. Hierarchical cluster analysis based on similarity matrix of DGGE profiles revealed changes in bacterial community composition in soils due to differences in nutrient management, and these changes were seen to occur according to the states of C and N dynamics in acidic soil under RLR rotation

    AAUOKHYB -1 : An excellent Okra hybrid developed by Assam Agricultural University (AAU) suitable for diverse agro-climatic situation of North East India

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    A hybrid development programme on okra (Abelmoschus esculentus) was undertaken at the Assam Agricultural University (AAU), Jorhat. The work included collection and evaluation of okra germplasm, identification of parents for hybridization, selfing of identified parental lines, making crosses and production of hybrid seeds, testing of hybrids for yield and resistance to Yellow Vein Mosaic Virus (YVMV) disease, adaptability under diverse agro-climatic condition and testing in all India trials. The programme resulted in development and identification of excellent Okra hybrid AAUOKHYB-1 in 2017.&nbsp; The performance of the hybrid was very good under diverse agro-climatic conditions yielding about 162.0 q/ha fruit yield which is 32.5% higher than the best commercial check Arka Anamika. The hybrid showed resistant (R) reaction to YVMV disease. A wide range of heterosis upto 43% was exhibited by the hybrid in different vegetable research centers of the country as compared to the best check variety

    Sub-Fourier characteristics of a δ\delta-kicked rotor resonance

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    We experimentally investigate the sub-Fourier behavior of a δ\delta-kicked rotor resonance by performing a measurement of the fidelity or overlap of a Bose-Einstein condensate (BEC) exposed to a periodically pulsed standing wave. The temporal width of the fidelity resonance peak centered at the Talbot time and zero initial momentum exhibits an inverse cube pulse number (1/N31/N^{3}) dependent scaling compared to a 1/N21/N^{2} dependence for the mean energy width at the same resonance. A theoretical analysis shows that for an accelerating potential the width of the resonance in acceleration space depends on 1/N31/N^{3}, a property which we also verify experimentally. Such a sub-Fourier effect could be useful for high precision gravity measurements.Comment: 4 pages, 5 figure

    A Study on the Thermal Behaviours of Eri, Muga and Pat Fibres

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    Continuous Correction of Differential Path Length Factor in Near-Infrared Spectroscopy

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    In continuous-wave near-infrared spectroscopy (CW-NIRS), changes in the concentration of oxyhemoglobin and deoxyhemoglobin can be calculated by solving a set of linear equations from the modified Beer-Lambert Law. Cross-talk error in the calculated hemodynamics can arise from inaccurate knowledge of the wavelength-dependent differential path length factor (DPF). We apply the extended Kalman filter (EKF) with a dynamical systems model to calculate relative concentration changes in oxy- and deoxyhemoglobin while simultaneously estimating relative changes in DPF. Results from simulated and experimental CW-NIRS data are compared with results from a weighted least squares (WLSQ) method. The EKF method was found to effectively correct for artificially introduced errors in DPF and to reduce the cross-talk error in simulation. With experimental CW-NIRS data, the hemodynamic estimates from EKF differ significantly from the WLSQ (p\u3c0.001 ). The cross-correlations among residuals at different wavelengths were found to be significantly reduced by the EKF method compared to WLSQ in three physiologically relevant spectral bands 0.04 to 0.15 Hz, 0.15 to 0.4 Hz and 0.4 to 2.0 Hz (p\u3c0.001 ). This observed reduction in residual cross-correlation is consistent with reduced cross-talk error in the hemodynamic estimates from the proposed EKF method

    Species distribution mapping and sustainability measures for a fungus economy in the Indian Himalaya

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    This presentation was given as part of the GIS Day@KU symposium on November 16, 2016. For more information about GIS Day@KU activities, please see http://gis.ku.edu/gisday/2016/.A entomopathogenic fungus, a fungus that kills its host caterpillar to proliferate. This fungus cures a plethora of ailments. It is one of the most expensive natural resources of the world and a resource that emancipated many from poverty in the remote mountains in the Tibetan plateau and the adjoining high altitude areas of Central and Eastern Himalaya. Geographically, a fine resolution information is lacking for majority of its distribution area. We explored a small region Askot landscape in the state Uttarakhand in Western Himalaya in India. The quest culminated in an extensive questionnaire survey with the villagers and harvesters. A current distribution map based on survey and a predicted suitable zone map using MaXent was produced. The concept is based on distributional ecology of a species which cross sections into concepts of species distribution model and ecological niche modelling. The inputs included both abiotic and biotic factos, albiet complexity. After repeated calibration and manual evaluation analysis, we chose elevation, aspect, slope and 12 PCA inputs of 68 MODIS 13Q1 NDVI layers (2012-2013) as the input data. Presence only data distributed as 10 random replicate pairs is used for training data and evalutation. Occurrence data is error free as it is a primary source data. Model evaluation returned a AUC ratio > 1 values for each, indicating that Maxent curve was significantly elevated above the bull expectations. The process of generating a suitability map convinced us of a sustainable harvest approach for safeguarding direct benefit to people's livelihood and indirectly the local environment.Platinum Sponsors: KU Department of Geography and Atmospheric Science. Gold Sponsors: Enertech, KU Environmental Studies Program, KU Libraries. Silver Sponsors: Douglas County, Kansas, KansasView, State of Kansas Data Access & Support Center (DASC) and the KU Center for Global and International Studies

    DELINEATING ECO-SENSITIVE ZONES USING GEOSPATIAL METHODS – A TEST CASE OF JHILMIL JHEEL CONSERVATION RESERVE

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    Most of the protected areas (PAs) in India have a hard boundary; very rarely having a transition zone to minimise the negative human wildlife interface. With increasing anthropogenic pressures, areas surrounding PAs are becoming integral for conservation. Government of India introduced a concept of Eco-sensitive Zones (ESZ) around PAs to minimise anthropogenic pressures and regulate rapid development in these areas. However, delineation of ESZs is a complex process and may take a long time. In this paper, a novel geospatial approach has been presented to delineate ESZ using a species centric approach. A case study using Swamp deer (Rucervus duvaucelli duvaucelli) as focal species was explored for its potential to delineate ESZ around protected area Jhilmil Jheel Conservation Reserve (JJCR) located in Uttarakhand India. Maximum entropy or Maxent model was used to identify habitat suitability. Normalised difference vegetation index (NDVI), altitude, land cover and distance to roads were used as co-variates. Seasonal variations for habitat suitability were also considered. In this study habitat suitability map of swamp deer was further rationalised based on habitat fragmentation and management limitations and proposed as ESZ of JJCR. This approach for delineation of ESZ can be very useful for PAs in India which have focal species and are yet to declare their ESZ
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