Search

Present investigation was made to evaluate effect of PGRs on shoot and root length of Fagopyrum esculentum. Results revealed that there was increase in shoot length by GA at 100 mg l-1 and root length by IAA at 50 mg l-1 at 30, 60 and 90 days of plant growth. ABA at 25 mg l-1 and 100 mg l-1 decreased shoot length as well root length. BAP at 100 mg l-1 also decreased root length. In combinations, IAA+GA 100 mg l-1 treatment enhanced shoot length as well as root length. Decrease in shoot length was observed in IAA+ABA, ABA+BAP (50 and 100 mg l-1) and root length by ABA+BAP (100 mg l-1) treatment.

The Hoyle analogue state in $$^{16}$$ O was explored by inelastic scattering of 45 MeV $$\alpha $$ s on a Mylar target. The break up 4 $$\alpha $$ s of $$^{16}$$ O have been detected in coincidence with the inelastically scattered $$\alpha $$ beam particle to probe the Hoyle analogue state of $$^{16}$$ O in complete kinematics, for the first time. The data have been analysed for all possible configurations and the excitation function of $$^{16}$$ O has been reconstructed directly from 4 $$\alpha $$ as well as for specific decay channels like $$^{12}$$ C(0 $$^{+}_{2}$$ ) + $$\alpha $$ , $$^{12}$$ C(3 $$^{-}_{1}$$ ) + $$\alpha $$ and $$^{8}$$ Be + $$^{8}$$ Be. Several previously known states have been observed above the $$4\alpha $$ break-up threshold (14.44 MeV) in the above mentioned decay channels. However, the signature of the 15.1 MeV state, most preferable to be the Hoyle analogue state according to the theoretical prediction, remains inconclusive.

Background: The excitation energy dependence of the fission fragment mass and folding angle distributions for reactions with loosely bound projectiles are reported to be significantly different compared to the reactions with tightly bound nuclei. Extensive study to understand the reaction mechanism of weakly bound projectiles is required as it can simulate the mechanism of fission induced with radioactive ion beams.Purpose: The effect of loosely bound nuclei on fission fragment folding angle and mass distributions in the $^{9}\mathrm{Be}+^{238}\mathrm{U}$ reaction near the Coulomb barrier energies is investigated and the contributions of incomplete fusion fission in the total fission cross section are studied.Methods: Mass and folding angle distributions of the fission fragments have been measured near the Coulomb barrier energies using two large area multiwire proportional counters. Fragment masses were determined from the time-of-flight difference method. To understand the effect of breakup of loosely bound nuclei, the results are compared with tightly bound proton-, $\ensuremath{\alpha}$-particle-, and carbon-induced reactions, as well as with the predictions from semiempirical calculations.Results: The width of folding angle distributions is found to increase with lowering excitation energy in the $^{9}\mathrm{Be}+^{238}\mathrm{U}$ reaction. This is in contrast to the reaction $^{12}\mathrm{C}+^{232}\mathrm{Th}$ involving tightly bound projectiles, populating similar compound nuclei. The peak-to-valley ratios of the fission fragment mass distributions for all events are found to sharply increase with lowering excitation energy in the $^{9}\mathrm{Be}+^{238}\mathrm{U}$ reaction. The possible contribution of incomplete fusion into the total fission cross section could be extracted. The measured mass distributions were found to be consistent with the semiempirical calculation gef and macro-microscopic two-center shell model calculations considering the admixture of incomplete fusion fission.Conclusion: For actinide targets, mass distributions of inclusive fission are influenced by the breakup/transfer channels of the weakly bound projectiles. At the above-barrier energies, the contribution of incomplete fusion is found to be $\ensuremath{\approx}25\ifmmode\pm\else\textpm\fi{}4%$ which is similar to the reported value of the complete fusion suppression factor in reactions involving nuclei with low binding energies. The increase in the peak-to-valley ratio with lowering excitation energy in the fission fragment mass distribution could be explained by the combined analysis of folding angle and mass distributions.

The fragment emission mechanism in the binary decay of composites formed in the reactions $^{20}\mathrm{Ne}+^{56}\mathrm{Fe}$ and $^{16}\mathrm{O}+^{58}\mathrm{Ni}$ has been studied at two different excitation energies. The inclusive energy and angular distributions of the emitted fragments $^{6,7}\text{Li}$, $^{7,8,9}\text{Be}$, $^{10,11}\text{B}$, and $^{11,12,13,14}\text{C}$ have been measured in the laboratory angles ranging from ${15}^{\ensuremath{\circ}}$ to ${35}^{\ensuremath{\circ}}$ (corresponding angles in center of mass ranging from ${20}^{\ensuremath{\circ}}$ to ${50}^{\ensuremath{\circ}}$). The energy distributions of the fragments are found to be Gaussian and peaked at energies higher than those expected from fusion-fission-type reactions. The center-of-mass angular distributions of all the fragments have been found to fall faster than $\ensuremath{\approx}1/\mathrm{sin}{\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}$-like dependence and the average $Q$ values of the fragments are found to decrease with increasing the center-of-mass angle of the emitted fragment for both the systems. The above characteristics of fragments signify that they were emitted from nonequilibrium sources, produced in a highly energy damped deep-inelastic-type reaction. The lifetimes of the dinuclear composites estimated from the angular distributions of these fragments are found to be in the range of $\ensuremath{\approx}(0.5--2.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}22}$ s, which are smaller than the respective compound-nuclear lifetimes $[\ensuremath{\approx}(1.0--2.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21} \mathrm{s}]$. The angular-momentum dissipations estimated from the average kinetic energies of the fragments are found to be, for lighter fragments in particular, greater than those predicted by the empirical sticking limit.

Background: The recent surprising experimental discovery of asymmetric fission in the nucleus $^{180}\mathrm{Hg}$ at low excitation energy has renewed interest concerning our understanding of the role of nuclear shell effects in the dynamics of the fission process. New theoretical models have been developed that claim to successfully explain the observed asymmetric fission of $^{180}\mathrm{Hg}$ and also predict the nature of mass distributions of several other preactinide nuclei for which experimental data are scarce.Purpose: We investigated fragment-mass distributions in the fission of the preactinide nucleus $^{214}\mathrm{At}$ at different excitation energies near the Coulomb barrier. The present results were compared with the predictions from a recent state-of-the-art theoretical calculation, as well as with our previous measurement for the nearby nucleus $^{210}\mathrm{Po}$.Methods: A pulsed heavy-ion beam was used in the experiment. Fission fragments were detected with two large-area position-sensitive multiwire proportional counters placed at the folding angle. Mass distributions were extracted from time-of-flight differences and position information ($\ensuremath{\theta},\ensuremath{\phi}$) for the fission fragments.Results: An asymmetry in fragment-mass distribution in the fission of $^{214}\mathrm{At}$ was observed at an excitation energy of $\ensuremath{\approx}31$ MeV, where a shell effect is found to influence the potential energy surface. At higher excitation energies, mass distributions are predominantly symmetric indicating the absence of shell effects.Conclusion: This finding is consistent with the prediction of a recent macroscopic-microscopic dynamical model. However, for the preactinides, static models with nascent fragment shell structure are likely to produce similar results.

Plants need to counter continuous threats posed by the environment, such as pathogen attacks (fungi, viruses, insects, nematodes) and harsh physical conditions (drought, salinity, temperature, exposure to UV radiation). Plants recognize the threat signals through their receptors and sensors and activate defense responses to stabilize against these stresses. The responses include accumulation of secondary metabolites. Enhanced synthesis of secondary metabolites, called elicitation ensures the survival, persistence and competitiveness of the plant. Secondary metabolites include volatile oils, flavonoids, alkaloids, glycosides, tannins, resins etc that have been successfully exploited for vital sources for food additives, flavors, and industrially important pharmaceuticals. The improved production of the secondary metabolites through elicitation has unlocked a new area of research that could have significant economic benefits for the pharmaceutical and therapeutic (including neutraceutical) industry. The present review discusses about the different elicitation methods through various biotic (proteins, carbohydrates, plant growth promoting rhizobacteria, fungus, hormones) and abiotic elicitors (heavy metals, low and high temperature, light, salt, drought) that could bring about increased yield of secondary metabolites especially in medicinal plants beneficial to the medicinal and aromatic industry.

Secondary metabolites not only play vital role in plant defense against herbivory and other interspecies defenses but also used by humans as medicines, flavorings, pharmaceuticals, agrochemicals, fragrances, colours, biopesticides, food additives and drugs. Many of the drugs retailed today are simple synthetic modifications of the naturally obtained substances. The developing commercial status of secondary metabolites in recent years has resulted in a great interest in secondary metabolism. Different strategies have been extensively studied with the objective of improving the production of secondary metabolites in plants. Based on this limelight, the focus of the present review is to study the application of plant growth regulators for the production of some essential plant secondary metabolites. This review covers brief introduction of secondary metabolites and plant growth regulators and production of secondary metabolites by using different plant growth regulators according to their classification.

High and medium spin structures of 130,131Xe have been studied using α-induced fusion-evaporation reaction and the Indian National Gamma Array (INGA) coupled with a digital data acquisition system. Various new band structures and near yrast levels of 131Xe have been established. The multipolarities of the observed transitions have been assigned on the basis of the DCO ratios and the polarization asymmetry measurements. Band structures based on 1-quasi-particle (qp), 3-qp configurations have been observed. A new Magnetic Rotational (MR) band based on 5-qp configuration has also been established in 131Xe. The MR band has been interpreted in terms of shears mechanism with principal axis cranking (SPAC) calculations. Shell Model calculations are carried out to describe the non yrast states of 131Xe above the 11/2− isomer. New excited states have also been identified in 130Xe, produced in the same reaction.

After publication of the paper, the authors realized that one of the references was not correct. Its correct version appears in this erratum.

The cyclotron at Variable Energy Cyclotron Centre (VECC), Kolkata, has recentlyrecently completed its 40 years of operation in 2017. During the past four decades, VECC has been able to cross several milestones in exploring the properties of nuclei with the help of low energy light as well as heavy ions accelerated by the cyclotron. In this review, we endeavour to present an overall picture of the intense research activities in various branches of nuclear physics carried out in the past four decades using cyclotron, with special emphasis on the important achievements in each field.

Background: The influence of shell effect on the dynamics of the fusion fission process and its evolution with excitation energy in the preactinide Hg-Pb region in general is a matter of intense research in recent years. In particular, a strong ambiguity remains for the neutron shell closed $^{210}\mathrm{Po}$ nucleus regarding the role of shell effect in fission around $\ensuremath{\approx}30--40\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$ of excitation energy.Purpose: We have measured the fission fragment mass distribution of $^{210}\mathrm{Po}$ populated using fusion of $^{4}\mathrm{He}+^{206}\mathrm{Pb}$ at different excitation energies and compare the result with recent theoretical predictions as well as with our previous measurement for the same nucleus populated through a different entrance channel. Mass distribution in the fission of the neighboring nuclei $^{213}\mathrm{At}$ is also studied for comparison.Methods: Two large area multiwire proportional counters (MWPC) were used for complete kinematical measurement of the coincident fission fragments. The time of flight differences of the coincident fission fragments were used to directly extract the fission fragment mass distributions.Results: The measured fragment mass distribution for the reactions $^{4}\mathrm{He}+^{206}\mathrm{Pb}$ and $^{4}\mathrm{He}+^{209}\mathrm{Bi}$ were symmetric and the width of the mass distributions were found to increase monotonically with excitation energy above 36.7 MeV and 32.9 MeV, respectively, indicating the absence of shell effects at the saddle. However, in the fission of $^{210}\mathrm{Po}$, we find minor deviation from symmetric mass distributions at the lowest excitation energy (30.8 MeV).Conclusion: Persistence of shell effect in fission fragment mass distribution of $^{210}\mathrm{Po}$ was observed at the excitation energy $\ensuremath{\approx}31\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$ as predicted by the theory; at higher excitation energy, however, the present study reaffirms the absence of any shell correction in the fission of $^{210}\mathrm{Po}$.

The fission fragment mass distributions have been measured in the reactions 16O + 184W and 19F+ 181Ta populating the same compound nucleus 200Pb? at similar excitation energies. It is found that the widths of the mass distribution increases monotonically with excitation energy, indicating the absence of quasi-fission for both reactions. This is contrary to two recent claims of the presence of quasi-fission in the above mentioned reactions., Comment: Accepted for publication as a regular article in Physical Review C

The reaction [Formula: see text]Al([Formula: see text],3He) at 25 MeV beam energy has been utilized to study the states in even–even nucleus [Formula: see text]Mg. The spectroscopic factors have been extracted for the states of [Formula: see text]Mg up to 7.50[Formula: see text]MeV excitation energy using local, zero-range distorted wave Born approximation. The extracted spectroscopic factors have been compared with the previously reported values. The present results were also compared with the predictions from a theoretical shell model and rotational model.

The reaction 27 Al(d,t) at 25 MeV was utilized to study the excited states of 26 Al. The angular distributions of the observed excited states of 26 Al were analyzed with zero range distorted wave Born approximation as well as by incorporating finite range correction parameters to extract spectroscopic factors. The two sets of extracted spectroscopic factors were compared with each other to see the effect of using finite range correction in the transfer form factor.