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In this minireview, we intend to shed light on relatively recent examples related to the size and shape effects on materials at the nanoscale and their usage to test a set of quantum mechanics governed phenomena.

Caregivers play an important role for the treatment and wellbeing of the psychiatric patients. Constant caregiving role exert stress on the caregiver which is usually handled by them. This cross-sectional study aimed to assess the level of stress and coping status among conveniently selected 171 care givers of major psychiatric patients at National Institute of Mental Health (NIMH), Dhaka. Data was collected by the pre-tested semi-structure questionnaire blended with perceived stress and coping scale through face to face interview. Average coping status was found in most of the (70%) care givers; good coping status was found in more than one fifth (21%) of the caregivers and few (02%) caregivers had poor coping status. Stress and coping status was found (p

Introduction: Thalassemia is the most common congenital single gene disorder in Bangladesh. Considering the nature of the disease inherited from parents, thalassemia can effectively be prevented by premarital blood screening before marriage. The aim of the study was to assess the level of knowledge and awareness regarding premarital screening of β-thalassemia among undergraduate students. Materials and Methods: This cross sectional study was conducted among conveniently selected 156 undergraduate students of 2 universities at Dhaka University and American International University-Bangladesh (AIUB) from January to December 2019. Data were collected by pretested semi-structured questionnaire through face to face interview. Data was analyzed using SPSS software version 23. Results: It was found that about 49.5%, 43.6% and 7.1% of respondents had poor, average and good knowledge about premarital screening of β-thalassemia respectively where there was statistical significance between the level of knowledge and the parental consanguinity and the family history of thalassemia (p-value

A simple modification of the Vaisburd and Evdokimov model (VE) [Russ. Phys. J. 46 , 1160 (2003)], with a acronym MVE, embodying the relativistic effects is proposed and employed to evaluate the K -shell ionization cross sections of atomic targets with atomic numbers 6 ≤ Z ≤ 92 for incident energies E Threshold ≤ E ≤ 10 GeV. For a meaningful comparison we also revisited our earlier MUIBED model [Int. J. Q. Chemistry, 108 , 1023 (2008)] to obtain the K -shell ionization cross sections for 24 atomic targets and above mention energy range. It is found that our new results from the MVE model agrees quite well not only with available experimental data but also with other theoretical values.

The differential, total, momentum transfer and viscosity cross sections for the elastic scattering of electrons and positrons by ytterbium atoms have been calculated. We have also calculated the total inelastic and ionization cross sections. In addition, the Sherman function S(θ) and the inelastic mean free paths have been determined for the scattering of both projectiles. The critical minima in the elastic differential cross sections (DCS) were determined from the analysis of the DCS and S(θ). These investigations have been carried out within the framework of two different theoretical approaches at the impact energies 1 eV–0.5 GeV for both projectiles. In the atomic domain the solution involves a complex projectile-atom optical potential while in the nuclear domain only the nuclear potential has been employed. Both approaches employ the Dirac partial wave analysis. Our results are in reasonable agreement with available experimental data and other theoretical findings. To the best of our knowledge, for positron scattering, there are no experimental data available in the literature.

This paper reports on the differential, integral, momentum transfer and viscosity cross sections along with spin polarisation for elastically scattered electrons and positrons from iron atoms in th...

Stopping cross sections (SCS) for protons, alphas and Li ions are calculated with a modified form of our earlier work by incorporating a different electron density distribution of target materials; this involves four parameters – two projectile dependent and the rest two remain fixed. The prosed model has been tested for three stripped ion (H+, He2 + and Li3 +) projectiles and found that it describes quite satisfactorily the experimental SCS data from low energies with projectile velocities nearing v = Z1v0 (with Z1 as the atomic number and v0 the Bohr velocity) up to 100.0 MeV over a wide range of stopping media with atomic numbers Z2 =3–100.

Synopsis Vaisburd and Evdokimov proposed an empirical VE model to calculate the electron impact single ionization cross-sections of atoms and molecules. The extension of the modified VE model (MVE) has been proposed incorporating the relativistic effects. This model is applied to investigate the total L-shell as well as L1-, L2- and L3-subshells ionization cross-sections of various atomic targets with atomic numbers Z =1892 for incident energies up to 1 GeV. The results from the MVE model are compared with the available experimental data and theoretical findings.

The differential, total, and momentum transfer cross sections along with the minima in the differential cross sections (DCSs) and the Sherman function S(θ) for the elastic scattering of electrons by calcium atoms have been calculated. These calculations are done within the framework of complex electron–atom optical potential and relativistic dynamics, in the energy range 1–2000 eV. The results obtained are in good agreement with the available experimental data and are better than the previous calculations in overall assessment. In the DCSs, the energies and angular positions of five critical minima have been confirmed. In the vicinity of these critical minima, nine maximum polarization points have been found within the range −0.90 ≤ S(θ) ≤ +0.73. Near the critical minima, a strong energy dependence of maximum polarization points is found.

Within the framework of the complex optical potential, the critical minima (CM) in the differential cross sections and the spin polarization in the elastic scattering of electrons by the Sr atom are studied in the energy range E i = 1–1000 eV using the Dirac and Schrödinger partial wave methods. The two methods are, respectively, termed as the optical potential method of Dirac (OPMD) and optical potential method of Schrödinger (OPMS). The differential cross sections (DCSs), total cross sections (TCSs), momentum transfer cross sections (MTCSs), integral elastic cross sections (IECSs), viscosity cross sections (VCSs) and inelastic cross sections (INCSs) for e–Sr scattering are also calculated for the same energy range. In OPMD, the complex optical potential is composed of the static, exchange, polarization and absorption potentials. The OPMS potential, on the other hand, comprises the static, local exchange, polarization, spin-orbit, and absorption components. The number of CM points has been found to be respectively 7 and 5 with OPMD and OPMS methods in the DCSs of e–Sr scattering. The number of maximum spin polarization points observed is 13 and 10 for the OPMD and OPMS respectively. The energy dependence of TCS, MTCS, IECS, VCS, and INCS, studied in this work, show a non-monotonous pattern for energies beyond about 50 eV. So far as we are concerned, this is the first work for the study of CM in the DCSs of the e–Sr scattering as there are neither experimental nor theoretical studies published in the literature for the same.

Absolute angular differential, integrated elastic and momentum transfer cross-sections for elastically scattered electrons from the ions () of argon isonuclear series, over the energy range 3.3–100 eV, are calculated employing a complex electron-ion optical potential within the framework of Dirac relativistic partial wave analysis. The cross sections are analyzed in terms of the contributions from pure Coulomb filed and the short range electron-ion complex optical potential comprising static, exchange, correlation-polarization and absorption potentials. Comparison of our calculations with the available experimental data and other theoretical calculations shows a satisfactory agreement.

The model of Cengiz (2002) [Approximate inelastic scattering cross sections of electrons. Rad. Phys. Chem. 65, 33–44] has been modified by incorporating both the ionic and relativistic corrections due to Uddin et al. (2006) [Modified Kolbensvedt model for the electron impact K-shell ionization cross-sections of atoms and ions. Eur. Phys. J. D 37, 361–369.] to investigate the electron impact s-orbital ionization in the K- and L-shells. With a single set of species independent parameters our evaluated inner shell ionization cross section of atomic targets from H to U over incident energies up to 2 GeV and of H- to Be-isoelectronic series reproduce the experimental findings nicely.

The elastic, differential and integrated, and total cross sections for the scattering of electrons and positrons by magnesium atom have been calculated. These calculations are done within the framework of complex electron/positron-atom optical potential and relativistic Dirac partial wave analysis at the impact energies 0.1–1000 eV for both the projectiles. The present results are compared with available experimental data and some other theoretical calculations.

The spin-polarization S and the spin-polarization parameters U and T of the elastically scattered electrons from Hg atoms have been computed for scattering angles 0°–180° in the energy range 1 eV . An optical model approach is employed using a complex optical potential within the framework of the Dirac relativistic partial wave analysis. We compare our results with recent experiments and available theoretical calculations and find a reasonable agreement with experiments over a wide range of energies.

This paper presents a detailed study of integral four- and five-count filter methods for the measurement of mixed radon and thoron daughter concentrations in air. The four-count method utilizes beta activity measurement while the five-count method is based on alpha activity measurement with plastic track detectors. A good correlation between the two independent detection techniques has been observed. An adequate theoretical framework is provided by interpreting the observed data.

CR-39 solid state nuclear track detectors were used to determine the indoor and underground radon activity at three locations in the northern part of Bangladesh. The indoor radon activity at Naogaon was found to be higher than that at Rajshahi and Ruppur. Radon concentration in the mud-built houses at Naogaon was estimated to be ∼500 Bq m -3 (14pCil -1 ) which is more than three times the recommended limit. The underground radon emanation at Naogaon was found to be one order of magnitude higher than that at the other two places.

Electron impact ionization cross sections for E ≤ 10 keV are presented for O and its isoelectronic series (F+, Ne2+ and Si6+ ions) and compared with experimental and other theoretical results.

We propose an extension of our recently modified simplified-improved-binary-encounter dipole (MUIBED) model [1] suitable even for relativistic energies. This new model (XMUBED) is applied to calculate the electron impact single M-subshell ionization cross-sections for atomic targets with various charges Z (79 ≤ Z ≤ 92). The parameters of the MUIBED model for the M-shell ionization calculations are modified to account well for fourteen atomic targets (between Au and U) for the inner M-subshell ionization cross sections.

The recently proposed generalized Kolbenstvedt model (GKLV) of Haque et al (2007 Eur. Phys. J. D 42 203), for the electron impact ionization (EII) of atoms, was applied to a wide range of K-, L- and M-shell electrons of ionic targets from threshold to 1 MeV incident energy. The set of species-independent parameters, two for each of the ionized orbits, is the same as that for neutral targets, and provides an excellent account of the EII cross-sectional data for 36 ions, including those belonging to Li, Be, B, C, N, O and Ne electronic sequences as well as those having 3s-, 3p- and 3d-configurations of the M-shell in a consistent manner. The performance of GKLV is found to be better than that of the modified version of the BELL model (Haque et al 2006 Phys. Rev. A 73 052703, Haque et al 2006 Phys. Scr. 74 377).