1,187 research outputs found

    Relaxation of thermo-remanent magnetization in Fe-Cr GMR multilayers

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    The time decay of the thermo-remanent magnetization (TRM) in Fe-Cr giant magnetoresistive (GMR) multilayers has been investigated. The magnetization in these multilayers relaxes as a function of time after being cooled in a small magnetic field of 100 Oe to a low temperature and then the magnetic field is switched off. Low-field (<< 500 Oe) magnetization studies of these samples have shown hysteresis. This spin-glass-like behavior may originate from structural imperfections at the interfaces and in the bulk. We find that the magnetization relaxation is logarithmic. Here the magnetic viscosity is found to increase first with increasing temperature, then it reaches a maximum around Tg_g, and then it decreases with increasing temperature. This behavior is different from that of conventional spin glasses where the logarithmic creep rate is observed to increase with temperature. Power law also gives good fits and it is better than the logarithmic fit at higher temperatures. The dynamical effects of these multilayers are related to the relaxation of thermally blocked superparamagnetic grains and magnetic domains in the film layers.Comment: 19 page

    Comparison of genetic diversities in native and alien populations of hoary mustard (Hirschfeldia incana [L.] Lagreze-Fossat)

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    Increased selfing and inbreeding and, consequently, depauperate genetic diversities are commonly expected for alien colonies. We compared RAPDs data for native (southern Europe) and alien (British Isles) populations of hoary mustard (Hirschfeldia incana). This species is normally out-breeding, but it is capable of self- fertilization. Contrary to the common expectations, genetic diversities in native and alien populations were similar, without any strong evidence of decreased levels of genetic diversities in alien populations. A variety of factors may have contributed to this observation, including high variation in founding groups, founders originating from multiple H. incana source populations, and high rates of past and/or current gene flow. A review of other studies showed that this pattern of similar genetic diversities in native and alien populations was not unusual but has been regularly observed in other invasive plant species

    Genome-wide and Mendelian randomisation studies of liver MRI yield insights into the pathogenesis of steatohepatitis

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    Background A non-invasive method to grade the severity of steatohepatitis and liver fibrosis is magnetic resonance imaging (MRI) based corrected T1 (cT1). We aimed to identify genetic variants influencing liver cT1 and use genetics to understand mechanisms underlying liver fibroinflammatory disease and its link with other metabolic traits and diseases. Methods First, we performed a genome-wide association study (GWAS) in 14,440 Europeans in UK Biobank with liver cT1 measures. Second, we explored the effects of the cT1 variants on liver blood tests, and a range of metabolic traits and diseases. Third, we used Mendelian randomisation to test the causal effects of 24 predominantly metabolic traits on liver cT1 measures. Results We identified six independent genetic variants associated with liver cT1 that reached GWAS significance threshold (p<5x10-8). Four of the variants (rs75935921 in SLC30A10, rs13107325 in SLC39A8, rs58542926 in TM6SF2, rs738409 in PNPLA3) were also associated with elevated transaminases and had variable effects on liver fat and other metabolic traits. Insulin resistance, type 2 diabetes, non-alcoholic fatty liver and BMI were causally associated with elevated cT1 whilst favourable adiposity (instrumented by variants associated with higher adiposity but lower risk of cardiometabolic disease and lower liver fat) was found to be protective. Conclusion The association between two metal ion transporters and cT1 indicates an important new mechanism in steatohepatitis. Future studies are needed to determine whether interventions targeting the identified transporters might prevent liver disease in at risk individuals

    Performance Evaluation of 50HP Three Phase Induction Motor Drive using Vector Control

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    This paper introduces a novel technique for performance evaluation of three phase induction motor drive. A suitable value of DC supply is applied to three phase inverter, which provides controlled three phase ac supply to induction motor. Performance of this 50HP drive is considers for three cases; (a) no load condition (b) half load condition (c) Full load condition. Performance evaluation is also done for dynamic condition. Results obtained from simulation model are satisfactory and shows good dynamic performance of drive

    Determining Significant Connectivity by 4D Spatiotemporal Wavelet Packet Resampling of Functional Neuroimaging Data

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    An active area of neuroimaging research involves examining functional relationships between spatially remote brain regions. When determining whether two brain regions exhibit significant correlation due to true functional connectivity, one must account for the background spatial correlation inherent in neuroimaging data. We define background correlation as spatiotemporal correlation in the data caused by factors other than neurophysiologically based functional associations such as scanner induced correlations and image preprocessing. We develop a 4D spatiotemporal wavelet packet resampling method which generates surrogate data that preserves only the average background spatial correlation within an axial slice, across axial slices, and through each voxel time series, while excluding the specific correlations due to true functional relationships. We also extend an amplitude adjustment algorithm which adjusts our surrogate data to closely match the amplitude distribution of the original data. Our method improves upon existing wavelet-based methods and extends them to 4D. We apply our resampling technique to determine significant functional connectivity from resting state and motor task fMRI datasets

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    Not AvailableA field experiment was carried out at Sardarkrushinagar Dantewada Agricultural University (SDAU), during two consecutive winter seasons of 2006-07 and 2007-08 to study effect of nitrogen, phosphorus and biofertilizer on growth dynamics, productivity and nutrient uptake of fenugreek. The experiment consisting of sixteen treatment combinations with two levels each of nitrogen (N) (10 and 20 kg N/ha) and P2O5 (20 and 40 kg P2 O5/ ha) and four levels of seed inoculation with bio-fertilizers (no seed inoculation (control), seed inoculation with Rhizobium alone, seed inoculation with phosphate solubilising bacteria (PSB) alone and seed inoculation with both Rhizobium+ PSB) was laid in factorial randoblized block design (FRBD) with three replications. Application of 20 kg N and 40 kg P2 O5/ha significantly increased dry matter accumulation per plant (DMA), crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) at all the growth stages as well as seed yield, straw yield, net return, benefit cost ratio (BCR) and, N, P and K uptake by crop over their respective lower levels. Inoculation of seed with both Rhizobium and PSB gave the highest DMA, CGR, RGR and NAR over their sole application as well as control. Seed and straw yield as well as, net return, BCR and, N, P and K uptake by crop was also recorded significantly higher with Rhizobium + PSB seed inoculation followed by Rhizobium alone. Thus, higher seed and straw yield as well as net return and BCR of fenugreek can be realised with the application of 20 kg N/ha, 40 kg P2O5 / ha and seed inoculation with Rhizobium and PSB both.Not Availabl

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    Not AvailableA field experiment was carried out at Sardarkrushinagar Dantewada Agricultural University (SDAU), during two consecutive winter seasons of 2006-07 and 2007-08 to study effect of nitrogen, phosphorus and biofertilizer on growth dynamics, productivity and nutrient uptake of fenugreek. The experiment consisting of sixteen treatment combinations with two levels each of nitrogen (N) (10 and 20 kg N/ha) and P2O5 (20 and 40 kg P2 O5/ ha) and four levels of seed inoculation with bio-fertilizers (no seed inoculation (control), seed inoculation with Rhizobium alone, seed inoculation with phosphate solubilising bacteria (PSB) alone and seed inoculation with both Rhizobium+ PSB) was laid in factorial randoblized block design (FRBD) with three replications. Application of 20 kg N and 40 kg P2 O5/ha significantly increased dry matter accumulation per plant (DMA), crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) at all the growth stages as well as seed yield, straw yield, net return, benefit cost ratio (BCR) and, N, P and K uptake by crop over their respective lower levels. Inoculation of seed with both Rhizobium and PSB gave the highest DMA, CGR, RGR and NAR over their sole application as well as control. Seed and straw yield as well as, net return, BCR and, N, P and K uptake by crop was also recorded significantly higher with Rhizobium + PSB seed inoculation followed by Rhizobium alone. Thus, higher seed and straw yield as well as net return and BCR of fenugreek can be realised with the application of 20 kg N/ha, 40 kg P2O5 / ha and seed inoculation with Rhizobium and PSB both.Not Availabl

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    Not AvailableA field experiment was conducted during 2008-09 and 2009-10 post-rainy seasons at Navsari, Gujarat to evaluate the effects of land configuration, fertilizers and farm yard manure (FYM) application on productivity, water use efficiency, nutrient uptake, soil fertility status and the economics of green gram ( Vigna radiata L.) cultivation. The raised bed method of planting was found superior as was evident from significant increase in growth and yield attributes, grain (0.93 t/ha) and stover yield (2.27 t/ha), irrigation water use efficiency (IWUE), nitrogen (N), phosphorus (P) and potassium (K) uptake, net returns ( 37.6 × 103/ha) and B:C ratio (3.9) and decrease in plant mortality percent. Application of 100% recommended dose of nitrogen (20 kg/ha) and phosphorus (40 kg P2O5/ha) recorded significantly higher growth and yield attributes, grain and stover yield, IWUE, NPK uptake, available NPK in the soil, net returns and B:C ratio over the application of 75% of recommended dose of N and P. Similarly, the application of FYM at 5t/ha recorded statistically higher growth and yield attributes, grain and stover yield, IWUE, NPK uptake, available NPK in the soil after harvest, net returns and B:C ratio and decrease in plant mortality percent over no FYM application.Not Availabl
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