Measurement of the Branching Fraction for B->eta' K and Search for B->eta'pi+

We report measurements for two-body charmless B decays with an eta' meson in the final state. Using 11.1X10^6 BBbar pairs collected with the Belle detector, we find BF(B^+ ->eta'K^+)=(79^+12_-11 +-9)x10^-6 and BF(B^0 -> eta'K^0)=(55^+19_-16 +-8)x10^-6, where the first and second errors are statistical and systematic, respectively. No signal is observed in the mode B^+ -> eta' pi^+, and we set a 90% confidence level upper limit of BF(B^+-> eta'pi^+) eta'K^+- decays is investigated and a limit at 90% confidence level of -0.20<Acp<0.32 is obtained.Comment: Submitted to Physics Letters

The variability of the black hole image in M87 at the dynamical timescale

The black hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5–61 days) is comparable to the 6 day extent of the 2017 EHT observations. Closure phases along baseline triangles are robust interferometric observables that are sensitive to the expected structural changes of the images but are free of station-based atmospheric and instrumental errors. We explored the day-to-day variability in closure-phase measurements on all six linearly independent nontrivial baseline triangles that can be formed from the 2017 observations. We showed that three triangles exhibit very low day-to-day variability, with a dispersion of ∼3°–5°. The only triangles that exhibit substantially higher variability (∼90°–180°) are the ones with baselines that cross the visibility amplitude minima on the u–v plane, as expected from theoretical modeling. We used two sets of general relativistic magnetohydrodynamic simulations to explore the dependence of the predicted variability on various black hole and accretion-flow parameters. We found that changing the magnetic field configuration, electron temperature model, or black hole spin has a marginal effect on the model consistency with the observed level of variability. On the other hand, the most discriminating image characteristic of models is the fractional width of the bright ring of emission. Models that best reproduce the observed small level of variability are characterized by thin ring-like images with structures dominated by gravitational lensing effects and thus least affected by turbulence in the accreting plasmas.https://iopscience.iop.org/article/10.3847/1538-4357/ac332e/pdfPublished versio

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Not AvailableAttempt was made to adjust three rice crops in a cropping sequence in irrigated lowland, and also to compare productivity and efficiency of rice (Oryza sativa L.)–rice–rice cropping system with rice–rice and rice–fallow. Results of the 8 years study (2001–09) revealed that rice variety ‘Chandrama’ as winter crop, followed by the same variety as summer crop and ‘Vandana’ as autumn crop could be grown in sequence. The grain yield from the 3 rice cropping sequence was 15.3 t/ha. The productivity of the summer crop (6.8 t/ha) was the highest, followed by the winter crop (5.6 t/ha). The lowest productivity was obtained from autumn crop (2.9 t/ha). Rice–rice cropping system produced the lower grain yield of 12.4 t/ha. However, considering production efficiency (48.8 kg grain/ha/day), sustainable yield index (0.98), net return (23,187/ha) and benefit: cost ratio (1.43), it was better than rice– rice–rice cropping system. Results on soil chemical properties after eight cropping cycles under rice–rice–rice cropping system revealed that soil pH and available N content were similar to the initial value. However, a buildup of organic carbon (12%), and available phosphorus (39.5%) and potassium (6.4%) in soil was noted.Not Availabl

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Journal ArticleA field experiment was carried out during early ahu (summer) season of 2013 and 2014 at the research farm of Regional Rainfed Lowland Rice Research Station, Gerua, Asom to study the influence of dates of sowing and varieties on growth and yield of direct wet sown rice during early ahu season in flood prone lowland ecosystem. The treatments consists of three dates of sowing viz., 5th Feb., 15th Feb. and 25th Feb. in main plots and two varieties viz., ‘Abhishek’ and ‘Naveen’ in sub-plots. Growth and yield attributes like days to 50% flowering, panicles per unit area, grains per panicle, test weight and grain filling percentage showed significant response to different dates of sowing. The crop sown on 15th February recorded higher grain yield of 5.41 t/ha. The high yield was due to more panicles per unit area, grains per panicle, test weight and grain filling %. Delay in sowing to 25th February resulted low grain and straw yield. This was due to poor grain filling % which in turn was due to high rain fall during flowering and grain filling stage. Among the two varieties tested, ‘Abhishek’matured early by 6 days and yielded (5.07 t/ha) compared to ‘Naveen’ (4.95t/ha). The later variety had more panicles per unit area (317.2 vs. 305.8) but less test weight of grains (20.5 vs. 22.2 g). Sowing of early ahu rice on 15th February recorded higher gross return and B:C ratio as compared to early or late sowing.Not Availabl

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Not AvailableA field experiment was conducted during the rainy (kharif) season of 2011 and 2012 at Gerua, Hajo, Asom to assess the performance of high-yielding varieties of rice (Oryza sativa L.) under double-transplanting method in rainfed lowland rice ecosystem of lower Brahmaputra Valley of Asom. The experiment consists of 10 treatment combinations, viz. 2 plant stand establishment methods (normal transplanting and double transplanting) in main plots and 5 rice varieties ‘Ranjit’, ‘Swarna’, ‘Swarna Sub 1’, ‘Sabita’ and ‘Pooja’ in subplots. Double transplanting recorded significantly increase in grain yield by 9.4% over normal transplanting. The increase in grain yield was owing to increase in number of panicles/unit area, number of grains/panicle, grain filling percentage and 1,000grain weight. Among the rice varieties ‘Swarna’ recorded significantly higher grain yield of 6.16 t/ha followed by ‘Ranjit’ (5.67 t/ha) and ‘Swarna Sub 1’ (5.65 t/ha). Under double transplanting, ‘Swarna’ recorded the highest benefit cost ratio of 2.03 and least production cost of 5.03/kg of grain, while ‘Sabita’ recorded lowest benefit: cost ratio of 1.10 due to lowest yield (4.20 t/ha) and poor market priceNot Availabl

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Not AvailableThe experiment was conducted during 2011 and 2012 to study the efficacy of liquid seaweed sap of Kappaphycus alvarezii and Gracilaria edulis on growth and yield performance of summer rice in a lowland field at Gerua, Assam. The treatments consisted of Kappaphycus (K) sap and Gracilaria(G) sap, each in four different doses viz., 2.5%, 5%, 10% and 15% in combination with recommended doses of fertilizer (RDF); and were compared with RDF in combination with water spray, and, also with the 7.5% K sap+50% RDF. A total of 10 treatments were evaluated and the results indicated that rice grain yield was increased by 13.8% and 10.3% in the treatments 5% K sap+ RDF and 5%G sap+ RDF, respectively, as compared to RDF + water spray. The increase in yield was attributed to increase in the number of panicles per unit area, number of filled grains panicle−1 and test weight. Highest net return ( 29751 ha−1) and benefit: cost ratio(1.75) was obtained under 5%K sap+RDF with 20% increase in net return as compared to RDF + water spray. Application of 5% K or G sap in combination with RDF increased grain and straw yield, net income and benefit:cost ratio of summer rice.Not Availabl

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Not AvailableA field experiment was carried out during the winter (rabi) season of 2010–11 and 2011–12 at the research farm of Regional Rainfed Lowland Rice Research Station, Gerua, Asom, to study the effect of dates of planting and mulching on growth and yield of potato (Solanum tubersoum L.) in rice fallows of rainfed shallow lowland ecosystem. The treatments consisted of 6 dates of planting, viz. 30 October, 10 November, 20 November, 30 November, 10 Decemer and 20 December in main plots and with and without mulch in subplots. Growth and yield attributes like days to emergence, plant height, leaf-area index, tubers/plants, tuber yield and dry-matter content of tubers showed significant response to different dates of planting. Planting on 30 November registered higher plant population, tubers/plant and tuber dry-matter which resulted higher tuber yield (13.91 t/ha) than early or late planting. Early planting on 30 October recorded poor tuber yield of 7.92 t/ha which was due to poor crop stand. The yield components and yield of potato were positively influenced by the use of paddy straw mulch. Mulch with paddy straw recorded 24% increase in tuber yield over no mulch. Higher yield of potato under mulch might be owing to better crop stand, higher percentage of large tubers and better tuber dry matter. Common scab affected tuber percentage was significantly less in 30 November-planted plots (20%) as compared to other planting dates. Mulch with paddy straw reduced the incidence of common scab by 16% over no mulching.Not Availabl

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Not AvailableWith increasing agricultural production after green revolution in India, generation of agricultural waste is a concern for clean agricultural production system. The purpose of the study is to recycle locally available agricultural wastes into vermicompost and apply it on crops. In this study vermicomposts prepared from combinations of four sources of each plant biomass and animal excreta were characterized and tested for yield and quality of green bell pepper (Capsicum annum L.). Vermicompost samples were analyzed for macronutrients, micronutrients and enzymatic activities at intermediate (40 d) and final (80 d) stages of decomposition. During composting, total organic carbon content of the bedding material decreased and C: N ratio was narrowed down. Zinc, Cu, and Mn contents were decreased by 6.9–177.3%, 28.5–318.5% and 0.7–207.4%, respectively, while Fe content increased by 15.4–64.3% in the matured samples. Acid phosphomonoesterase and dehydrogenase activities were reduced by 2.5–26.0% and 15.5–84.1%, respectively; while the β-glucosidase activity of vermicompost from cow dung and pig dung was increased by 2.0–30.7% at maturity. Application of vermicompost along with NPK fertilizers enhanced morphological, biochemical and yield attributes of green bell pepper which in-turn improved yield (7.1–135.7%) over the control. Vermicomposts also improved soil fertility by increasing organic C and plant-available N, P and K. Hierarchical cluster analysis revealed that the properties of mature vermicomposts were mainly determined by the animal excreta. Poultry litter along with paddy straw and Azolla pinnata proved to be superior raw material in the production of high quality vermicompost which could produce good quality and quantity of fruits. The study also suggests that production of vermicompost from locally available plant biomass and animal excreta will sustain crop harvest with quality produce and improve soil fertility.Not Availabl