Cluster decay half lives of trans-lead nuclei within the Coulomb and proximity potential model

Within the Coulomb and proximity potential model (CPPM) the cluster decay process in {199-226}^Fr, {206-232}^Ac, {209-237}^Th, {212-238}^Pa, {217-241}^U, {225-242}^Np, {225-244}^Pu, {231-246}^Am, {202-230}^Ra and {233-249}^Cm isotopes leading to the doubly magic 208^Pb and neighbouring nuclei are studied. The computed half lives are compared with available experimental data and are in good agreement with each other. The half lives are also computed using the Universal formula for cluster decay (UNIV) of Poenaru et al, Universal decay law (UDL) and the scaling law of Horoi et al, and their comparisons with CPPM values are found to be in agreement. The calculations for the emission of 22^O, 20^O, 20^O from the parents {209-237}^Th, {202-230}^Ra and {217-240}^U respectively were the experimental values are not available are also done. It is found that most of the decay modes are favourable for measurement, and this observation will serve as a guide to the future experiments. The odd-even staggering (OES) are found to be more prominent in the emission of odd mass clusters. The Geiger - Nuttall plots of log_10(T_1/2) vs. Q^{-1/2} for various clusters ranging from 14^C to 34^Si from different isotopes of heavy parent nuclei with atomic numbers within the range 87 \leq Z \leq 96 have been studied and are found to be linear. Our study reveals the role of doubly magic 208^Pb daughter nuclei in cluster decay process and also reveal the fact that the role of neutron shell closure is crucial than proton shell closure.Comment: 39 pages, 8 figure

Initial wave packets and the various power-law decreases of scattered wave packets at long times

The long time behavior of scattered wave packets $\psi (x,t)$ from a finite-range potential is investigated, by assuming $\psi (x,t)$ to be initially located outside the potential. It is then shown that $\psi (x,t)$ can asymptotically decrease in the various power laws at long time, according to its initial characteristics at small momentum. As an application, we consider the square-barrier potential system and demonstrate that $\psi (x,t)$ exhibits the asymptotic behavior $t^{-3/2}$, while another behavior like $t^{-5/2}$ can also appear for another $\psi (x,t)$.Comment: 5 pages, 1 figur

Incidence of arthropods in dried fish products

Arthropods have been recorded from various types of insect infested dried fish products stored in the laboratory. They have been identified as Suidesia nesbetti Hughes (Acaridae) infesting dried anchovies and dried mussel, Dermestes ater Dermestidae coleoptera) attacking wet cured sardines and smoked catfish and Stegobium panicium infesting smoked catfish and dried mussel. Incidences of Stegobium panicium in dry fish products and Suidesia nesbetti in dried mussel has been recorded for the first time

Proposal for an experiment to search for Randall-Sundrum type corrections to Newton's law of gravitation

String theory, as well as the string inspired brane-world models such as the Randall-Sundrum (RS) one, suggest a modification of Newton's law of gravitation at small distance scales. Search for modifications of standard gravity is an active field of research in this context. It is well known that short range corrections to gravity would violate the Newton-Birkhoff theorem. Based on calculations of RS type non-Newtonian forces for finite size spherical bodies, we propose a torsion balance based experiment to search for the effects of violation of this celebrated theorem valid in Newtonian gravity as well as the general theory of relativity. We explain the main principle behind the experiment and provide detailed calculations suggesting optimum values of the parameters of the experiment. The projected sensitivity is sufficient to probe the Randall-Sundrum parameter up to 10 microns.Comment: 4 pages and 5 figures, figures improved, minor clarifications and few references added, final version to appear in PRD (rapid communications

Transition region of TEC enhancement phenomena during geomagnetically disturbed periods at mid-latitudes

Large-scale TEC perturbations/enhancements observed during the day sectors of major storm periods, 12-13 February 2000, 23 September 1999, 29 October 2003, and 21 November 2003, were studied using a high resolution GPS network over Japan. TEC enhancements described in the present study have large magnitudes (≥25×10<sup>16</sup> electrons/m<sup>2</sup>) compared to the quiet-time values and long periods (≥120 min). The sequential manner of development and the propagation of these perturbations show that they are initiated at the northern region and propagate towards the southern region of Japan, with velocities >350 m/s. On 12 February 2000, remarkably high values of TEC and background content are observed at the southern region, compared to the north, because of the poleward expansion of the equatorial anomaly crest, which is characterized by strong latitudinal gradients near 35° N (26° N geomagnetically). When the TEC enhancements, initiating at the north, propagate through the region 39-34° N (30-25° N geomagnetically), they undergo transitions characterized by a severe decrease in amplitude of TEC enhancements. This may be due to their interaction with the higher background content of the expanded anomaly crest. However, at the low-latitude region, below 34° N, an increase in TEC is manifested as an enhanced ionization pattern (EIP). This could be due to the prompt penetration of the eastward electric field, which is evident from high values of the southward Interplanetary Magnetic Field component (IMF <i>B<sub>z</sub></i>) and AE index. The TEC perturbations observed on the other storm days also exhibit similar transitions, characterized by a decreasing magnitude of the perturbation component, at the region around 39-34° N. In addition to this, on the other storm days, at the low-latitude region, below 34° N, an increase in TEC (EIP feature) also indicates the repeatability of the above scenario. It is found that, the latitude and time at which the decrease in magnitude of the perturbation component/amplitude of the TEC enhancement are matching with the latitude and time of the appearance of the high background content. In the present study, on 12 February 2000, the F-layer height increases at Wakkanai and Kokubunji, by exhibiting a typical dispersion feature of LSTID, or passage of an equatorward surge, which is matching with the time of occurrence of the propagating TEC perturbation component. Similarly, on 29 October 2003, the increase in F-layer heights by more than 150km at Wakkanai and 90 km at Kokubunji around 18:00 JST, indicates the role of the equatorward neutral wind. On that day, TEC perturbation observed at the northern region, after 18:30 JST, which propagates towards south, could be caused mainly by the equatorward neutral wind, leading to an F-layer height increase. These observations imply the role of the equatorward neutral wind, which increases the F-layer height, by lifting the ionization to the regions of lower loss during daytime, when production is still taking place, which, in turn, increases the TEC values. <P style="line-height: 20px;"> Large-scale traveling ionospheric disturbances (LSTIDs) are considered as ionospheric manifestations of the passage of Atmospheric Gravity Waves (AGWs) that are generated at the high latitude by energy input from the magnetosphere to the low-latitude ionosphere. This study shows that large-scale TEC perturbations observed here are produced at the northern region due to the combined effects of the equatorward neutral wind, the subsequent F-layer height increase, and LSTIDs. When these perturbation components propagate through the region, 39-34° N, they undergo transitions characterised by a decrease in magnitude. Also, at the low-latitude region, below 34° N, an increase in the TEC exhibits EIP feature, due to the prompt penetration of the eastward electric field

Squilloides leptosquilla, a deepsea stomatopod landed at Kalamukku Fishing Harbour, Kochi

The mantis shrimp, Squilloides leptosquilla (Brooks, 1886) was obtained from deepsea trawl operations along with the deepsea shrimps, Plesionika spinipes, Heterocarpus gibbosus and Metapenaeopsis andamanensis from the Kalamukku Fishing Harbour during September, 2008

Free initial wave packets and the long-time behavior of the survival and nonescape probabilities

The behavior of both the survival S(t) and nonescape P(t) probabilities at long times for the one-dimensional free particle system is shown to be closely connected to that of the initial wave packet at small momentum. We prove that both S(t) and P(t) asymptotically exhibit the same power-law decrease at long times, when the initial wave packet in momentum representation behaves as O(1) or O(k) at small momentum. On the other hand, if the integer m becomes greater than 1, S(t) and P(t) decrease in different power-laws at long times.Comment: 4 pages, 3 figures, Title and organization changed, however the results not changed, To appear in Phys. Rev.

The Chandrayaan-2 Large Area Soft X-ray Spectrometer (CLASS)

The CLASS experiment on Chandrayaan-2, the second Indian lunar mission, aims tomap the abundance of the major rock forming elements on the lunar surface using the technique of X-ray fluorescence during solar flare events. CLASS is a continuation of the successful C1XS [1] XRF experiment on Chandrayaan-1. CLASS is designed to provide lunar mapping of elemental abundances with a nominal spatial resolution of 25 km (FWHM) from a 200 km polar, circular orbit of Chandrayaan-2

Standard and derived Planck quantities: selected analysis and derivations

We provide an overview of the fundamental units of physical quantities determined naturally by the values of fundamental constants of nature. We discuss a comparison between the 'Planck units', now widely used in theoretical physics and the pre-quantum 'Stoney units' in which, instead of the Planck constant, the charge of the electron is used with very similar quantitative results. We discuss some of the physical motivation for these special units, attributed much after they were introduced, and also put forth a summary of the arguments supporting various cases for making specific physical interpretations of the meanings of some of these units. The new aspects we discuss are a possible physical basis for the Stoney units, their link to the Planck units, and also the importance of Planck units for thermodynamical quantities in the context of quantum gravity.Comment: 22 pages, 1 tabl