Weyl collineations that are not curvature collineations

Though the Weyl tensor is a linear combination of the curvature tensor, Ricci tensor and Ricci scalar, it does not have all and only the Lie symmetries of these tensors since it is possible, in principle, that "asymmetries cancel". Here we investigate if, when and how the symmetries can be different. It is found that we can obtain a metric with a finite dimensional Lie algebra of Weyl symmetries that properly contains the Lie algebra of curvature symmetries. There is no example found for the converse requirement. It is speculated that there may be a fundamental reason for this lack of "duality".Comment: 9 page

Conformal Ricci collineations of static spherically symmetric spacetimes

Conformal Ricci collineations of static spherically symmetric spacetimes are studied. The general form of the vector fields generating conformal Ricci collineations is found when the Ricci tensor is non-degenerate, in which case the number of independent conformal Ricci collineations is \emph{fifteen}; the maximum number for 4-dimensional manifolds. In the degenerate case it is found that the static spherically symmetric spacetimes always have an infinite number of conformal Ricci collineations. Some examples are provided which admit non-trivial conformal Ricci collineations, and perfect fluid source of the matter

Callus Induction and Somatic Embryogenesis of Rice (Oryza sativa L.) Improvement with the Addition of Coconut Water

The study was conducted to determine the appropriate concentration of coconut water (CW) that enhance an efficient and cost effective protocol for rice micropropagation through callus induction and somatic embryogenesis.Seeds of a local Iraqi rice (Oryza sativa L.) cultivar Amber33, were used as explant which inoculated on basal medium consists of MS inorganic salts, Gamborg vitamins and supplemented with the auxin 2,4-Dichlorophenoxyacetic acid (2,4-D) and the cytokinin Benzyl adenine (BA). In order to evaluate the role of CW, three concentrations (10, 20 and 30 g.l-1) were added to MS inorganic salts after the exclusion of growth regulators (2.4-D and BA) and Gamborg vitamins. Results showed that adding CW especially at concentration of 30g.l-1 have minimized the callus induction period, enhanced callus fresh weight and numbers and germination percentage of somatic embryos when compared with the media enriched with growth regulators only. Keywords: Rice, callus induction, Somatic embryogenesis, coconut water.

Fluxon analogues and dark solitons in linearly coupled Bose-Einstein condensates

Two effectively one-dimensional parallel coupled Bose-Einstein condensates in the presence of external potentials are studied. The system is modelled by linearly coupled Gross-Pitaevskii equations. In particular, grey-soliton-like solutions representing analogues of superconducting Josephson fluxons as well as coupled dark solitons are discussed. Theoretical approximations based on variational formulations are derived. It is found that the presence of a magnetic trap can destabilize the fluxon analogues. However, stabilization is possible by controlling the effective linear coupling between the condensates.Comment: 14 pages, 7 figures, The paper is to appear in Journal of Physics

Prevalence of Vitamin B12 deficiency in patients of type 2 diabetes mellitus on metformin: A case control study from Pakistan

Introduction: Diabetes Mellitus is the most common endocrine disorder and metformin is the most commonly prescribed oral hypoglycemicagent. Metformin is well known to cause viamin B12 deficiency due to effect on calcium-dependent membrane action in the terminal ileum leading to malabsorption of vitamin B12. The purpose of this study is to determine prevalence and associations of Vitamin B12 deficiency in patients of type 2 diabetes mellitus treated with metformin. Methods: This case control study was carried out in department of medicine, Combined Military Hospital, Kharian from 1st Jan 2012 to 30 december 2012.We enrolled 114 outdoor patients of type 2 diabetes mellitus currently on metformin for atleast 12 months, by consecutive sampling, and 105 age and sex matched patients taken as control. Patients with vitamin B12 levels of less than 150 pg/ml were said to be B12 deficient. The results were analyzed on SPSS version 16.Results: Serum B12 levels were low in 35 patients (31%) on metformin as compared to only 9 patients (8.6%) among controls,(p value 0.002). Mean B12 levels were significantly low in metformin group 311 pg/ml (±194.4), p value 0.03. Dose of metformin had inverse correlation with B12 levels and the difference was statistically significant with pvalue < 0.001.Conclusion: Our study demonstrated significantly high prevalence of  vitamin B12 deficiency in patients treated with metformin with significant effect of dose and duration of metformin use on B12 levels. Physicians must recognize this important fact and screen diabetics on metformin therapy for underlying B12 deficiency

Knowledge and practice of radiation safety among invasive cardiologists

OBJECTIVE: To assess the availability, practices and knowledge of radiation safety measures among invasive cardiologists in a tertiary care hospital. METHOD: A cross sectional survey of invasive cardiologists working in academic institutions was conducted using a questionnaire. RESULTS: A total of 28 cardiologists completed the questionnaire with a mean working experience of 10.5 + 7.6 years. All were of the opinion that radiation safety is extremely important and 93% always used lead aprons. Less than half of them used other radiation protective measures including thyroid collar, lead eyeglasses and lead shields. Only 7% regularly utilized a radiation dose badge to monitor the exposure. This may be related to the availability, as lead aprons are readily available but other devices i.e. lead glasses, lead shield and radiation dose badge is available to less than a third of them. On evaluating knowledge only one fourth knew more than 60% of the answers to questions testing the basic principles of radiation safety. When working experience of cardiologists was correlated with their knowledge and practice of radiation safety surprisingly a paradoxical relationship was noted. Mean number of correct answers in those with experience of \u3e 10 years vs \u3c 10 years was 45% vs 56%, p \u3c 0.03. All of the above findings are probably because less than 50% have received any formal education in this important field. CONCLUSIONS: There is a lack of standard radiation safety measures and equipments in cardiac catheterization laboratories. Significant lapses exist in practice and lack of knowledge of radiation safety among invasive cardiologists in this part of the world. With rapid growth in the number of cardiac catheterization laboratories in developing countries significant improvement in knowledge, practice and availability of radiation safety measures is needed

Role of Salicylic Acid in the Improvement of PEG – Induced Drought Stress in Maize (Zea mays L.) cv. Baghdad

Laboratory experiment using hydroponic culture system was conducted at plant physiology laboratory, Department of Biology, College of Education for Pure  Sciences, University of Basrah, in order to study the role of seeds soaking with salicylic acid (SA) and the effect of PEG8000 induced water stress on germination and early seedling growth stages of maize (Zea mays L.) cv. Baghdad. Seeds were soaked with three concentrations of SA (0.1,0.3 and 0.5 mM) in addition to control treatment with distilled water, while PEG8000 were used at concentrations of  0% (distilled water) 1%, 2%, 3%, 6%, 9% and 12%. The data was recorded on various parameters like seeds germination percentage, seedlings roots and shoot length and seedlings roots and shoot fresh and dry weight.The experiment was designed as completely randomized factorial with three replicates for each treatment. Results indicated that SA at 0.5 mM caused a significant increase in germination percentage roots and shoot length, roots and shoots fresh and dry weight while PEG8000 caused a significant decrease especially at its high concentrations (6% and 9%) in all the previous parameters. Interaction between SA at 0.5 mM and PEG had improved significantly germination percentage, shoot and roots length, shoot and roots fresh and dry weight so it had a positive significance effect on increasing the drought tolerance in maize. Keywords: Maize, Salicylic acid, PEG8000, Hydroponic, Germination, Seedling growth.

Planck's confirmation of the M31 disk and halo rotation

Planck's data acquired during the first 15.4 months of observations towards both the disk and halo of the M31 galaxy are analyzed. We confirm the existence of a temperature asymmetry, previously detected by using the 7-year WMAP data, along the direction of the M31 rotation, therefore indicative of a Doppler-induced effect. The asymmetry extends up to about 10 degrees (about 130 kpc) from the M31 center. We also investigate the recent issue raised in Rubin and Loeb (2014) about the kinetic Sunyaev-Zeldovich effect from the diffuse hot gas in the Local Group, predicted to generate a hot spot of a few degrees size in the CMB maps in the direction of M31, where the free electron optical depth gets the maximum value. We also consider the issue whether in the opposite direction with respect to the M31 galaxy the same effect induces a minimum in temperature in the Planck's maps of the sky. We find that the Planck's data at 100 GHz show an effect even larger than that expected.Comment: 4 pages, 1 table, 2 figures, in press as a Letter in A&

Planck view of the M82 galaxy

Planck data towards the galaxy M82 are analyzed in the 70, 100 and 143 GHz bands. A substantial north-south and East-West temperature asymmetry is found, extending up to 1 degree from the galactic center. Being almost frequency-independent, these temperature asymmetries are indicative of a Doppler-induced effect regarding the line-of-sight dynamics on the halo scale, the ejections from the galactic center and, possibly, even the tidal interaction with M81 galaxy. The temperature asymmetry thus acts as a model-independent tool to reveal the bulk dynamics in nearby edge-on spiral galaxies, like the Sunyaev-Zeldovich effect for clusters of galaxies.Comment: 4 pages, 3 figures, in press on A&