Exclusive light particle measurements for the system 19^{19}F + 12^{12}C at 96 MeV

Decay sequence of hot {31}^P nucleus has been investigated through exclusive light charged particle measurements in coincidence with individual evaporation residues using the reaction {19}^F (96 MeV) + {12}^C. Information on the sequential decay chain have been extracted by confronting the data with the predictions of the statistical model. It is observed from the present analysis that such exclusive light charged particle data may be used as a powerful tool to probe the decay sequence of the hot light compound systems.Comment: 13 pages, 8 figures, Physical Review C (in press

Deformation effects in 56^{56}Ni nuclei produced in 28^{28}Si+28^{28}Si at 112 MeV

Velocity and energy spectra of the light charged particles (protons and $\alpha$-particles) emitted in the $^{28}$Si(E$_{lab}$ = 112 MeV) + $^{28}$Si reaction have been measured at the Strasbourg VIVITRON Tandem facility. The ICARE charged particle multidetector array was used to obtain exclusive spectra of the light particles in the angular range 15 - 150 degree and to determine the angular correlations of these particles with respect to the emission angles of the evaporation residues. The experimental data are analysed in the framework of the statistical model. The exclusive energy spectra of $\alpha$-particles emitted from the $^{28}$Si + $^{28}$Si compound system are generally well reproduced by Monte Carlo calculations using spin-dependent level densities. This spin dependence approach suggests the onset of large deformations at high spin. A re-analysis of previous $\alpha$-particle data from the $^{30}$Si + $^{30}$Si compound system, using the same spin-dependent parametrization, is also presented in the framework of a general discussion of the occurrence of large deformation effects in the A$_{CN}$ ~ 60 mass region.Comment: 25 pages, 6 figure

Confinement and electron correlation effects in photoionization of atoms in endohedral anions: Ne@C60^{z-}

Trends in resonances, termed confinement resonances, in photoionization of atoms A in endohedral fullerene anions A@C60^{z-} are theoretically studied and exemplified by the photoionization of Ne in Ne@C{60}^{z-}. Remarkably, above a particular nl ionization threshold of Ne in neutral Ne@C60 (I_{nl}^{z=0}), confinement resonances in corresponding partial photoionization cross sections sigma_{nl} of Ne in any charged Ne@C60^{z-} remain almost intact by a charge z on the carbon cage, as a general phenomenon. At lower photon energies, omega < I_{nl}^{z=0}, the corresponding photoionization cross sections develop additional, strong, z-dependent resonances, termed Coulomb confinement resonances, as a general occurrence. Furthermore, near the innermost 1s ionization threshold, the 2p photoionization cross section sigma_{2p} of the outermost 2p subshell of thus confined Ne is found to inherit the confinement resonance structure of the 1s photoionization spectrum, via interchannel coupling. As a result, new confinement resonances emerge in the 2p photoionization cross section of the confined Ne atom at photoelectron energies which exceed the 2p threshold by about a thousand eV, i.e., far above where conventional wisdom said they would exist. Thus, the general possibility for confinement resonances to resurrect in photoionization spectra of encapsulated atoms far above thresholds is revealed, as an interesting novel general phenomenon.Comment: 6 pages, 4 figures, Latex2e, jpconf.cls styl

Parietal Cortex Regulates Visual Salience and Salience-Driven Behavior

Chen et al. show that inactivation of parietal cortex selectively reduces salience signals within prefrontal cortex and diminishes the influence of salience on visually guided behavior. The results demonstrate a causal role of parietal cortex in regulating salience signals within the brain and in controlling salience-driven behavior

A note on q-Bernstein polynomials

In this paper we constructed new q-extension of Bernstein polynomials. Fron those q-Berstein polynomials, we give some interesting properties and we investigate some applications related this q-Bernstein polynomials.Comment: 13 page

Deformation effects in the 28^{28}Si+12^{12}C and 28^{28}Si+28^{28}Si reaction Search

The possible occurence of highly deformed configurations is investigated in the $^{40}$Ca and $^{56}$Ni di-nuclear systems as formed in the $^{28}$Si+$^{12}$C,$^{28}$Si reactions by using the properties of emitted light charged particles. Inclusive as well as exclusive data of the heavy fragments and their associated light charged particles have been collected by using the {\sc ICARE} charged particle multidetector array. The data are analysed by Monte Carlo CASCADE statistical-model calculations using a consistent set of parameters with spin-dependent level densities. Significant deformation effects at high spin are observed as well as an unexpected large $^{8}$Be cluster emission of a binary nature.Comment: 3 pages latex, 2 eps figures, paper presented in "wokshop on physics with multidetector array (pmda2000)Calcutta, India (to be published at PRAMANA, journal of Physics, India

Highly deformed 40^{40}Ca configurations in 28^{28}Si + 12^{12}C

The possible occurrence of highly deformed configurations in the $^{40}$Ca di-nuclear system formed in the $^{28}$Si + $^{12}$C reaction is investigated by analyzing the spectra of emitted light charged particles. Both inclusive and exclusive measurements of the heavy fragments (A $\geq$ 10) and their associated light charged particles (protons and $\alpha$ particles) have been made at the IReS Strasbourg {\sc VIVITRON} Tandem facility at bombarding energies of $E_{lab} (^{28}$Si) = 112 MeV and 180 MeV by using the {\sc ICARE} charged particle multidetector array. The energy spectra, velocity distributions, and both in-plane and out-of-plane angular correlations of light charged particles are compared to statistical-model calculations using a consistent set of parameters with spin-dependent level densities. The analysis suggests the onset of large nuclear deformation in $^{40}$Ca at high spin.Comment: 33 pages, 11 figure

Diffuse versus square-well confining potentials in modelling AA@C60_{60} atoms

Attention: this version-$2$ of the manuscript differs from its previously uploaded version-$1$ (arXiv:1112.6158v1) and subsequently published in 2012 J. Phys. B \textbf{45} 105102 only by a removed typo in Eq.(2) of version-$1$; there was the erroneous factor "2" in both terms in the right-hand-side of the Eq.(2) of version-$1$. Now that the typo is removed, Eq.(2) is correct. A perceived advantage for the replacement of a discontinuous square-well pseudo-potential, which is often used by various researchers as an approximation to the actual C$_{60}$ cage potential in calculations of endohedral atoms $A$@C$_{60}$, by a more realistic diffuse potential is explored. The photoionization of endohedral H@C$_{60}$ and Xe@C$_{60}$ is chosen as the case study. The diffuse potential is modelled by a combination of two Woods-Saxon potentials. It is demonstrated that photoionization spectra of $A$@C$_{60}$ atoms are largely insensitive to the degree $\eta$ of diffuseness of the potential borders, in a reasonably broad range of $\eta$'s. Alternatively, these spectra are found to be insensitive to discontinuity of the square-well potential either. Both potentials result in practically identical calculated spectra. New numerical values for the set of square-well parameters, which lead to a better agreement between experimental and theoretical data for $A$@C$_{60}$ spectra, are recommended for future studies.Comment: 11 pages, 4 figure

The Contribution of Parietal Cortex to Visual Salience

Unique stimuli stand out. In spite of an abundance of competing sensory stimuli, the detection of the most salient ones occurs without effort, and that detection contributes to the guidance of adaptive behavior. Neurons sensitive to the salience of visual stimuli are widespread throughout the primate visual system and are thought to shape the selection of visual targets. However, the source of the salience computation has remained elusive. Among the possible candidates are areas within posterior parietal cortex, which appear to be crucial in the control of visual attention and are thought to play a unique role in representing stimulus salience. Here we show that reversible inactivation of parietal cortex not only selectively reduces the representation of visual salience within the brain, but it also diminishes the influence of salience on visually guided behavior. These results demonstrate a distinct contribution of parietal areas to vision and visual attention