Effective potential and geodesic motion in Kerr-de Sitter space-time

In the present work, geodesic trajectories in Kerr-de Sitter geometry is analyzed. From the mathematical solution of Lagrangian formalism appropriate to motions in the equatorial plane (for which 'theta' = 0 and 'theta' = (constant)= pi/2) can give potential energy of massive and massless particles for rotating axisymetric black hole. From this, for a particular value of cosmological constant, Kerr parameter, mass, angular momentum and impact parameter; variation of potential with distance can be found. Similarly, for a particular value of cosmological constant, mass and Kerr parameter; variation of velocity with distance can be found

Electric and Magnetic fields due to Dirac particles in FRW spacetime

Some solutions of the Maxwell equations with Dirac particles for the source in FRW spacetime are discussed. The Green's function of the equation for the radial component of the Maxwell fields, F_{r\eta} and F_{\theta\phi} is solved. Green's function is found to reduce to that of Minkowskian spacetime in the appropriate limit. Also, the Lienard-Wiechert type solution is derived. Also, the solutions with the Dirac particle current is also presented. It is found that the F_{r\eta} is composed of even angular momentum states while the odd states constitue F_{\theta\phi} .Comment: 8 pages including 2 figure

Involving Nepali academics in health research

JMBTO SEE JHIn a world dominated by globalization and knowledge exchange conducting research and academic publishing has become increasingly important. In this light it is important to report the findings of research conducted in Nepal as it may be relevant and useful in North Korea as in Namibia. The editorial outlines some of the barriers and opportunities that exist for academics in Nepal

The effect of mother’s educational status on early initiation of breastfeeding: further analysis of three consecutive Nepal Demographic and Health Surveys

Background: The World Health Organization recommends initiating breastfeeding within the first hour of birth. This study is aimed at assessing the effect of the mother’s education on early initiation of breastfeeding. Methods: Data from the Nepal Demographic and Health Surveys (NDHS) 2001, 2006 and 2011 were used which included 12,845 last born children born within 5 years before the surveys. Early initiation of breastfeeding was defined as the initiation of breastfeeding within the first hour after birth. Hierarchical modelling was used to ascertain the association of maternal education and early initiation of breastfeeding, after controlling for other covariates in a multiple logistic regression. Results: Maternal education was associated with a higher likelihood of early initiation of breastfeeding in each survey. Pooled data analysis revealed higher odds of early initiation of breastfeeding among the mothers with primary education (adjusted odds ratio (OR) 1.24, 95 % confidence interval (CI): 1.09, 1.42) and secondary or higher education (OR: 1.63 95 % CI: 1.42, 1.88). In the most recent NDHS 2011 survey, odds of early initiation of breastfeeding was higher among mothers with primary education (OR: 1.52; 95 % CI: 1.21, 1.91) and mothers with secondary or higher education (OR: 2.20; 95 % CI: 1.76, 2.76) compared to mothers with no education. Similarly, the odds of early initiation of breastfeeding was higher among mothers with secondary and higher education in the 2006 data (OR: 1.66; 95 % CI: 1.30, 2.12) and in 2001 (OR = 1.30; 95 % CI: 1.00, 1.67).Conclusions: As the association between a mother ’ s educational status and her likelihood of early initiation of breastfeeding increases, long-term approaches to prioritising education for women and girls should be explored. In the short term, uneducated mothers should be targeted with breastfeeding promotion strategies such as counselling and peer education

Investigation of Hot-Spots Due to Trapped Flux in Niobium Superconducting Radiofrequency Cavities

One of the significant sources of residual losses in superconducting radio-frequency cavities is magnetic flux trapped during the cool-down due to the incomplete Messier effect. If the trapped vortices are non-uniformly distributed on the cavity surface, the temperature mapping revealed the “hot-spots” at the location of high density of pinned vortices. Here, we performed a rf test on 1.3 GHz single cell cavity with the combination of the temperature mapping system. The temperature mapping reveled the development of the hot spots with the increase in rf field inside the cavity. When magnetic field is trapped locally on the surface of cavity, the hot-spots strength increase rapidly, showing the direct correlation of vortex induced hot spot and corresponding rf loss

Skin spots on ‘Cripps Pink’ and ‘Elstar’ apples are identical

Brown spots have recently been reported on the surfaces of ‘Cripps Pink’ apples, grown in Marsillargues, France. Preliminary observations suggest the symptoms on ‘Cripps Pink’ apples resemble those reported earlier on ‘Elstar’ apples and then referred to as ‘Elstar skin spots’. Elstar skin spots occur particularly in coastal production areas of northern Europe, and in rainy seasons. The objective of this study was to establish more definitively whether the skin spots observed on ‘Cripps Pink’ are identical to those reported on ‘Elstar’. Hence, the morphological and anatomical characteristics of ‘Cripps Pink’ skin spots were assessed in more detail. The skin spots on ‘Cripps Pink’ develop on the non-blush side of the fruit. High resolution scanning light microscopy revealed a network of cuticular microcracks in both symptomatic and non-symptomatic regions of an affected fruit. When fruits with microcracks were dipped in a 1:1 chloroform:methanol mixture, the width and depth of the microcracks increased, indicating that the microcracks had previously been partially filled with wax. The microcracks on a symptomatic surface were wider and deeper than those on a non-symptomatic surface. After the cuticular wax had been extracted (as above), the microcracks on the symptomatic surface were found to be partially infiltrated with the fluorescent dye acridine orange; but not so the microcracks on a non-symptomatic surface. The fruit skin of symptomatic apples had a higher rate of water loss than that of non-symptomatic apples. Microscopy revealed that the epidermal and some of the hypodermal cells beneath the microcracks within a symptomatic area were brown and their cell walls lignified. We infer from these observations that the skin spots on ‘Cripps Pink’ are identical to the well-known skin spots on ‘Elstar’ apples

Evaluation of flux expulsion and flux trapping sensitivity of srf cavities fabricated from cold work Nb sheet with successive heat treatment

The main source of RF losses leading to lower quality factor of superconducting radio-frequency cavities is due to the residual magnetic flux trapped during cool-down. The loss due to flux trapping is more pronounced for cavities subjected to impurities doping. The flux trapping and its sensitivity to rf losses are related to several intrinsic and extrinsic phenomena. To elucidate the effect of re-crystallization by high temperature heat treatment on the flux trapping sensitivity, we have fabricated two 1.3 GHz single cell cavities from cold-worked Nb sheets and compared with cavities made from standard fine-grain Nb. Flux expulsion ratio and flux trapping sensitivity were measured after successive high temperature heat treatments. The cavity made from cold worked Nb showed better flux expulsion after 800 C/3h heat treatments and similar behavior when heat treated with additional 900 C/3h and 1000 C/3h. In this contribution, we present the summary of flux expulsion, trapping sensitivity, and RF results.Comment: 21st International Conference on Radio-Frequency Superconductivity (SRF 2023