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Role of cluster structures of 7Li on reaction dynamics have been studied by performing exclusive measurements of prompt-γ rays from residues with scattered particles at energy, E/Vb = 1.6, with 198Pt target. Yields of the residues resulting after capture of t and 4,5,6He, corresponding to different excitation energies of the composite system were estimated. The results were compared with three body classical-dynamical model for breakup fusion, constrained by the measured fusion, α and t capture cross-sections. The cross-section of residues from capture of α and t agreed well with the prediction of the model showing dominance of the two step process - breakup fusion, while those from tightly bound 6He showed massive transfer to be the dominant mechanism.

The reaction mechanism of deep-inelastic multinucleon transfer processes in the 16O+27Al reaction at an incident 16O energy (Elab=134 MeV) substantially above the Coulomb barrier has been studied both experimentally and theoretically. Elastic-scattering angular distribution, total kinetic energy loss spectra, and angular distributions for various transfer channels have been measured. The Q-value- and angle-integrated isotope production cross sections have been deduced. To obtain deeper insight into the underlying reaction mechanism, we have carried out a detailed analysis based on the time-dependent Hartree-Fock (TDHF) theory. A recently developed method, TDHF+GEMINI, has been applied to evaluate production cross sections for secondary products. From a comparison between the experimental and theoretical cross sections, we find that the theory qualitatively reproduces the experimental data. Significant effects of secondary light-particle emissions are demonstrated. Possible interplay among fusion-fission, deep-inelastic, multinucleon transfer, and particle evaporation processes is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Exclusive measurements of prompt γ-rays from the heavy-residues with various light charged particles in the 7Li+ 198Pt system, at an energy near the Coulomb barrier () are reported. Recent dynamic classical trajectory calculations, constrained by the measured fusion, α- and t-capture cross-sections have been used to explain the excitation energy dependence of the residue cross-sections. These calculations distinctly illustrate a two-step process, breakup followed by fusion, in case of the capture of t and α clusters; whereas for and configurations, massive transfer is inferred to be the dominant mechanism. The present work clearly demonstrates the role played by the cluster structures of 7Li in understanding the reaction dynamics at energies around the Coulomb barrier. [Copyright &y& Elsevier]

Background: Reactions involving weakly bound projectiles with +x cluster structure are known to produce a large number of particles, where transfer-induced breakup is one of the possible origins. Detailed investigation on each of these channels is desirable to understand the underlying reaction mechanism. Purpose: Our purpose is to measure the +1p transfer-induced breakup in the 112Sn(7Li,8Bee22) reaction to understand the possible modes of 8Be breakup and their contribution to inclusive production. Methods: coincidence measurements have been carried out for the above reaction at Ebeam=30 MeV. Projectile-like fragments were detected using five sets of Si-strip-detector telescopes and five sets of single Si-detector telescopes. Optical model analysis of elastic scattering data, coupled reaction channels (CRC), and continuum discretized coupled channels (CDCC) calculations were performed to understand the measured cross sections. Results: The experimental cross sections for +1p transfer-induced breakup in (7Li,8Bee22) reaction through different resonance states of 8Be have been obtained. Relative energy distribution and Monte Carlo simulation confirm the observation of breakup of 8Be from its 4+ (11.35-MeV) resonant state for the first time along with its well-known 0+ (92-keV) and 2+ (3.12-MeV) resonances. Simultaneous description of elastic scattering, transfer, and breakup cross sections have been made using CDCC plus CRC formalism. Conclusions: Production of particles in +1p transfer-triggered breakup is found to proceed mainly through three resonance (0+,2+, and 4+) states of 8Be. [ABSTRACT FROM AUTHOR]

Direct and sequential breakups of the projectile in the 7Li+112Sn reaction have been measured at a beam energy of 30 MeV. Cross sections for sequential breakup of 7Li into α and t cluster fragments via its second resonant state of 5/2- (6.68 MeV) in the continuum have been measured for the first time along with the first resonant state (7/2-, 4.63 MeV). Probabilities of sequential breakup proceeding through -1n and -2n transfer channels, i.e., (7Li,6Li) and (7Li,5Li) reactions followed by breakup, into α+d and α+p, respectively, were found to dominate over α+t breakup. Measured cross sections for the above breakup channels and elastic scattering have been compared with coupled-channel calculations to understand the reaction mechanism involving the weakly bound projectile 7Li. Significant cross section for direct breakup of 7Li→6He+p has also been measured for the first time, indicating the importance of the new (6He+p) cluster configuration that may be necessary to understand the complete structure of 7Li and its energy levels. [ABSTRACT FROM AUTHOR]

Background: Experimental anisotropy in fission-fragment (FF) angular distribution in reactions involving weakly bound stable projectiles with actinide targets are enhanced compared to statistical saddle-point model (SSPM) predictions. Contributions from breakup- or transfer-induced fission to total fission are cited as possible reasons for such enhancement. Purpose: To identify the breakup- or transfer-induced fission channels in 6Li+ 232Th reaction and to investigate their effects on FF angular anisotropy. Methods: The FF angular distributions have been measured exclusively at three beam energies (28, 32, and 36 MeV) around the Coulomb barrier in coincidence with projectile breakup fragments like α, d, and p using Si strip detectors. The angular anisotropy obtained for different exclusive breakup- or transfer-induced fission channels are compared with that for total fission. SSPM and pre-equilibrium fission models have been employed to obtain theoretical FF angular anisotropy. Results: Angular anisotropy of the fission fragments produced by different transfer- or breakup-induced fission reactions have been obtained separately in the rest frame of respective recoiling nuclei. Some of these anisotropies were found to be stronger than those of the inclusive fission. Overall angular distributions of transfer or breakup fission, integrated over all possible recoil angles with weight factor proportional to differential cross section of the complementary breakup fragment emitted in coincidence in all possible directions, were obtained. It was observed that the overall FF angular anisotropy for each of these fission channels is less than or equal to the anisotropy of total fission at all the measured energies. Assuming isotropic out-of-plane correlations between the fission fragments and light-charged particles, the overall breakup- or transfer-induced fission fragment angular distributions do not explain the observed enhancement in FF anisotropy of total fission. Pre-equilibrium fission model provides a reasonable explanation of the enhanced experimental anisotropy of total fission. Conclusions: Angular anisotropies for different breakup or transfer fission channels involving emission of α, d, and p in the reaction plane have been measured for the 6Li + 232Th reaction. The overall FF angular anisotropies of breakup- or transfer-induced fissions do not explain the enhanced anisotropy of total fission at near-barrier energies. A measurement of out-of-plane correlation is necessary to confirm the above observation and obtain a complete picture on the effect of transfer or breakup on total fission. [ABSTRACT FROM AUTHOR]

We present a biologically inspired recurrent neural network (RNN) that efficiently detects changes in natural images. The model features sparse, topographic connectivity (st-RNN), closely modeled on the circuit architecture of a "midbrain attention network." We deployed the st-RNN in a challenging change blindness task, in which changes must be detected in a discontinuous sequence of images. Compared with a conventional RNN, the st-RNN learned 9x faster and achieved state-of-the-art performance with 15x fewer connections. An analysis of low-dimensional dynamics revealed putative circuit mechanisms, including a critical role for a global inhibitory (GI) motif, for successful change detection. The model reproduced key experimental phenomena, including midbrain neurons' sensitivity to dynamic stimuli, neural signatures of stimulus competition, as well as hallmark behavioral effects of midbrain microstimulation. Finally, the model accurately predicted human gaze fixations in a change blindness experiment, surpassing state-of-the-art saliency-based methods. The st-RNN provides a novel deep learning model for linking neural computations underlying change detection with psychophysical mechanisms. SIGNIFICANCE STATEMENT For adaptive survival, our brains must be able to accurately and rapidly detect changing aspects of our visual world. We present a novel deep learning model, a sparse, topographic recurrent neural network (st-RNN), that mimics the neuroanatomy of an evolutionarily conserved "midbrain attention network." The st-RNN achieved robust change detection in challenging change blindness tasks, outperforming conventional RNN architectures. The model also reproduced hallmark experimental phenomena, both neural and behavioral, reported in seminal midbrain studies. Lastly, the st-RNN outperformed state-of-the-art models at predicting human gaze fixations in a laboratory change blindness experiment. Our deep learning model may provide important clues about key mechanisms by which the brain efficiently detects changes., (Copyright © 2022 the authors.)

Among neurological complications associated with dengue, posterior reversible encephalopathy syndrome (PRES) has not been reported in pediatric population. We report a 10-year-old girl with severe dengue who developed PRES. The patient presented with hemorrhagic shock that required fluid resuscitation and inotropic support. She developed seizures with encephalopathy 2 days after recovering from the shock. Cerebrospinal fluid (CSF) examination was negative for dengue (no white blood cells in CSF with negative polymerase chain reaction for dengue). Her clinical features and magnetic resonance imaging (MRI) findings showed typical changes associated with posterior encephalopathy that reverted after resolution of hypertension. Repeat MRI after a month was normal. PRES should be considered as a possible differential diagnoses of dengue associated encephalopathy, especially in cases with normal CSF examination and characteristic MRI changes., (© The Author(s) [2019]. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Ischaemic heart disease (IHD) is a major health problem today. However the focus has shifted primarily to angiographically detecting epicardial vessel stenoses, and ways and means of surgically correcting the blocks. Patients are often not fully evaluated for cardiac function, and diastolic dysfunction of heart, which is often an earlier manifestation than systolic dysfunction, goes undetected., Methods: Recent gamma cameras have better imaging quality due to attenuation correction with SPECT-CT. 121 patients underwent gated myocardial perfusion imaging (MPI) for suspected coronary artery disease (CAD). We studied the diastolic function of these patients by 16-gated SPECT MPI., Results: 60% patients showed absence of inducible ischaemia on MPI, and hence further invasive procedures like angiography were prevented, 40% showed inducible ischaemia and had to be further evaluated and required intervention. Of all 121 patients, 10% had LV systolic and diastolic dysfunction whereas 66% had isolated diastolic dysfunction. 40% patients had no ischaemia, normal systolic function and only diastolic dysfunction. 40% of these cases had symptoms of chest heaviness/angina equivalent., Conclusion: Myocardial perfusion imaging is a useful modality for evaluating patients of suspected CAD and in addition to perfusion data, also provides functional assessment of systolic and diastolic function, which provides comprehensive information regarding patients' symptomatology and can guide further management.