34,254 research outputs found
Modelling the quantitative evaluation of soil nutrient supply, nutrient use efficiency, and fertilizer requirements of wheat in India
No full textWheat yields in many parts of India are stagnant. The main reason for this is conventional blanket fertilizer recommendation, lower fertilizer use efficiency, and imbalanced use of fertilizers. Estimation of fertilizer requirements based on quantitative approaches can assist in improving wheat yields and increasing nutrient use efficiency. We used the QUEFTS (QUantitative Evaluation of Fertility of Tropical Soils) model for estimation of nitrogen (N), phosphorus (P), and potassium (K) requirements and fertilizer recommendations for a target yield of wheat. The model considers the interactions of N, P, and K, and climate adjusted potential yield of the region. Published data from several field experiments dealing with N, P, and K conducted during the years 1970 to 1998 across wheat-growing environments of India, covering a wide range of soil and climatic conditions, were used to reflect the environmental variability. The relationships between indigenous N, P, and K supply and soil organic carbon, Olsen P, and ammonium acetate-extractable K, respectively, were established. The required N, P, and K accumulation in the plant for 1 tonne grain yield was 23.1, 3.5, and 28.5 kg, respectively, suggesting an average NPK ratio in the plant dry matter of about 6.6:1:8.1. The constants for minimum and maximum accumulation (kg grain kg-1) of N (27 and 60), P (162 and 390), and K (20 and 59) were derived as the standard model parameters in QUEFTS for fertilizer recommendation for irrigated wheat in the tropical and subtropical regions of India. Relationships of apparent recovery efficiencies of fertilizer N, P, and K with levels of their application were also determined. The observed yields of wheat with different amounts of these nutrients were in good agreement with the values predicted by the model, indicating that the model can be used for fertilizer recommendations
Magnetic ground states of Ce3TiSb5, Pr3TiSb5and Nd3TiSb5 determined by neutron powder diffraction and magnetic measurements
No full textThe R 3TiSb5 ternary compounds, with R a light rare earth (La to Sm) have been reported to crystallize with the anti-Hf5CuSn3-type hexagonal structure (Pearson's symbol hP18; space-group P63/mcm, N. 193). An early article that reported possible superconductivity in some of these intermetallic phases (namely those with R = La, Ce, and Nd) caught our attention. In this work, we have now refined the crystal structure of the R 3TiSb5 compounds with R = Ce, Pr and Nd by Rietveld methods using high-resolution neutron powder diffraction data. The magnetic ground states of these intermetallics have been investigated by low-temperature magnetization and high-intensity neutron diffraction. We find two different magnetic transitions corresponding to two related magnetic structures at T N1 = 4.8 K (k 1 = [0, 1/2, 1/8]) and T N2 = 3.4 K (k 2 = [0, 0, 1/8]), respectively for Ce3TiSb5. However, the magnetic ordering appears to occur following a peculiar hysteresis: the k 2-type magnetic structure develops only after the k 1-type phase fraction has first slowly ordered with time and the size of the ordered Ce3+ magnetic moment has become large enough to induce the second magnetic transition. At T = 1.5 K the maximum amplitude of the Ce moment in the coexisting phases amounts to μ Ce = 2.15 μ B. For Nd3TiSb5 an antiferromagnetic ordering below T N = 5.2 K into a relatively simpler commensurate magnetic structure with a magnetic moment of μ Nd = 2.14(3) μ B and magnetic propagation vector of k = [0, 0, 0], was determined. No evidence of superconductivity has been found in Nd3TiSb5. Finally, Pr3TiSb5 does not show any ordering down to 1.5 K in neutron diffraction while an antiferromagnetic ground state is detected in magnetization measurements. There is no sign of magnetic contribution from Ti atoms found in any of the studied compounds
Tetragonal to triclinic structural transition in the prototypical CeScSi induced by a two-step magnetic ordering: a temperature-dependent neutron diffraction study of CeScSi, CeScGe and LaScSi
No full textAn investigation on the ground state magnetism of CeScSi, CeScGe (tetragonal CeScSi-type, tI12, space group I4/mmm) by temperature-dependent powder neutron diffraction has been carried out, as debated and controversial data regarding the low temperature magnetic behaviours of these two compounds were reported. Our studies reveal that, while cooling, long-range magnetic ordering in CeScSi and CeScGe takes place by a two-step process. A first transition leads to a magnetic structure with the Ce moments aligned ferromagnetically onto two neighbouring tetragonal basal a-b planes of the CeScSi-type structure; the double layers are then antiferromagnetically coupled to each other along the c-axis. The transition temperature associated with the first ordering is T N ~ 26 K and T N ~ 48 K for the silicide and the germanide, respectively. Here the spin directions are rigorously confined to the basal plane, with values of the Ce magnetic moments of μ Ce = 0.8-1.0 μ B. A second magnetic transition, which takes place at slightly lower temperatures, results in a canting of the ordered magnetic moments out of the basal plane which is accompanied by an increase of the magnetic moment value of Ce to μ Ce = 1.4-1.5 μ B. Interestingly, the second magnetic transition leads to a structural distortion in both compounds from the higher-symmetry tetragonal space group I4/mmm to the lower-symmetry and triclinic I-1 (non-standard triclinic). Magnetic symmetry analysis shows that the canted structure would not be allowed in the I4/mmm space group; this result further confirms the structural transition. The transition temperatures T S from I4/mmm to I-1 are about 22 K in CeScSi and 36 K in CeScGe, i.e. well below the temperature of the first onset of antiferromagnetic order observed in this work (or below the ordering temperature, previously reported as either T C or T N). This result, along with the synchronism of the magnetic and structural transitions, suggests a magnetostructural origin of this structural distortion. We have also carried out powder neutron diffraction for LaScSi as a non-magnetically-ordering reference compound and compared the results with those of CeScSi and CeScGe compounds
Fixed and coincidence points of hybrid mappings
No full textsummary:The purpose of this note is to provide a substantial improvement and appreciable generalizations of recent results of Beg and Azam; Pathak, Kang and Cho; Shiau, Tan and Wong; Singh and Mishra
In vitro comparison of K-file, Mtwo, and WaveOne in cleaning efficacy and instrumentation time in primary molars
No full textAim: The aim of this study was to compare instrumentation time and cleaning efficacy of manual instrumentation and two rotary systems in the preparation of primary molar root canals. Materials and Methods: The teeth were randomly divided into three experimental groups, Group 1 K-file (n = 30), Group 2 Mtwo (n = 30), Group 3 WaveOne (n = 30), and one control group (n = 30). The root canals were prepared using one of the three file systems followed by clearing the teeth with different demineralizing solutions. The instrumentation time in each root canal was measured by a chronometer. The results were statistically evaluated using Kruskal–Wallis tests.Results: In the coronal third, WaveOne showed more ink removal and the difference found was highly significant (P < 0.0001). In the middle third of the root canal, WaveOne performed better than Mtwo and K-file (P < 0.005). At the apical level, there was no statistical difference between the three systems. WaveOne was found to take significantly (P < 0.0001) less time than Mtwo and K-file. Conclusion: WaveOne took less time and showed better cleaning efficacy when compared to other instrumentation techniques, especially in coronal and middle one-third
Catheter ablation of atrial fibrillation in patients with concomitant left ventricular impairment: a systematic review of efficacy and effect on ejection fraction
No full textAbstract not availableAnand N. Ganesan, Savvy Nandal, Jakob Lüker, Rajeev K. Pathak, Rajiv Mahajan, Darragh Twomey, Dennis H. Lau, Prashanthan Sander
Obesity and the risk of incident, post-operative, and post-ablation atrial fibrillation: a meta-analysis of 626,603 individuals in 51 studies
No full textAbstract not availableChristopher X. Wong, Thomas Sullivan, Michelle T. Sun, Rajiv Mahajan, Rajeev K. Pathak, Melissa Middeldorp, Darragh Twomey, Anand N. Ganesan, Geetanjali Rangnekar, Kurt C. Roberts-Thomson, Dennis H. Lau, Prashanthan Sander
The shannon capacity on C(n,k)
No full textThis thesis focuses on a problem formulated by Claude Shannon named the Shannon capacity. This problem is about information rate per time unit over a noisy channel. The noisy channel is here represented by a graph. We specifically focus on a class of circulant graphs that are denoted by C(n,k) with vertex set z/nz, where all vertices are connected with the k-1 vertices before and after it. We will discuss upper bounds that were found for the Shannon capacity and how C(n,k) behaves with these upper bounds. After that we will focus on multiple ways to calculate lower bounds for the Shannon capacity of . For these three search methods will be used. These are exhaustive searching for optimal values, optimal ways to make packagings and solutions created by using a special form. As last the answers will be discussed by combining the upper and lower bounds for C(n,k). From this conclusions are drawn after which some possibilities will be given for further research. Applied Mathematic
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
Flip Distance Is in FPT Time O(n+ k * c^k)
No full textLet T be a triangulation of a set P of n points in the plane, and let e be an edge shared by two triangles in T such that the quadrilateral Q formed by these two triangles is convex. A flip of e is the operation of replacing e by the other diagonal of Q to obtain a new triangulation of P from T. The flip distance between two triangulations of P is the minimum number of flips needed to transform one triangulation into the other. The Flip Distance problem asks if the flip distance between two given triangulations of P is k, for some given k \in \mathbb{N}. It is a fundamental and a challenging problem.
In this paper we present an algorithm for the Flip Distance problem that
runs in time O(n + k \cdot c^{k}), for a constant c \leq 2 \cdot
14^11, which implies that the problem is fixed-parameter tractable. The
NP-hardness reduction for the Flip Distance problem given by Lubiw
and Pathak can be used to show that, unless the exponential-time hypothesis (ETH) fails, the Flip Distance problem cannot be solved in time O^*(2^o(k)). Therefore, one cannot expect an asymptotic improvement in the exponent of the running time of our algorithm
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