A numerical study of energy balances and flow planforms in earth's mantle with radioactive heating, the 660 km-depth phase boundary and continents

It is well established that the temperature gradients in the interiors of internally-heated mantle convection models are subadiabatic (e.g. Parmentier et al., 1994; Bunge et al., 1997, 2001). The subadiabatic gradients have been explained to arise due to a balance between vertical advection and internal heating, however, a detailed analysis of the energy balance in the subadiabatic regions has not been undertaken. In this research, I examine in detail the energy balance in a suite of two-dimensional convection calculations with mixed internal and basal heating, depth-dependent viscosity and continents. I find that there are three causes of subadiabatic gradients. One is the above-mentioned balance, which becomes significant when the ratio of internal heating to surface heat flux is large. The second mechanism involves the growth of the overshoot (maximum and minimum Temperatures along a geotherm) of the geotherm near the lower boundary where the dominant balance is between vertical and horizontal advection. The latter mechanism is significant even in relatively weakly internally heated calculations. For time-dependent calculations, I find that local secular cooling can be a dominant term in the energy equation and can lead to subadiabaticity. However, it does not show its signature on the shape of the time-averaged geotherm. I also compare the basal heat flux with parameterized calculations based on the temperature drop at the core-mantle boundary, calculated both with and without taking the subadiabatic gradient into account and I find a significantly improved fit with its inclusion. I also explore a wide range of parameter space to investigate the dynamical interaction between effects due to surface boundary conditions representing continental and oceanic lithosphere and the endothermic phase boundary at 660 km-depth in two-dimensional Cartesian coordinate convection calculations. I find that phase boundary induced mantle layering is strongly affected by the wavelength of convective flows and mixed surface boundary conditions strongly increase the horizontal wavelength of convection. My study shows that for mixed cases the effects of the surface boundary conditions dominate the effects of the phase boundary. I show that the calculations with complete continental coverage have the most significantly decoupled lower and upper mantle flows and substantial thermal and mechanical layering. Unlike the free-slip case where the surface heat flux decreases substantially with increasing magnitude of the Clapeyron slope, surface heat flux is shown to be almost independent of the Clapeyron slope for mixed boundary condition cases. Although very different when not layered, models with free and mixed surfaces have very similar planforms with very large aspect ratio flows when run with large magnitudes of the Clapeyron slope. I also calculate the critical boundary layer Rayleigh number as a measure of the thermal resistance of the surface boundary layer. My results show that the thermal resistance in the oceanic and the continental regions of the mixed cases are similar to fully free and no-slip cases, respectively. I find that, even for purely basally heated models, the mantle becomes significantly subadiabatic in the presence of partial continental coverage. This is due to the significant horizontal advection of heat that occurs with very large aspect ratio convection cells

Transfusion practices in obstetrics and gynaecology in a tertiary care center

Background: This study was an effort to identify and highlight existing transfusion practices in our hospital, including the indications of various blood components used and the allergic reaction encountered. Obstetric hemorrhage remains major cause of maternal mortality worldwide and Blood transfusion can be a lifesaving intervention.Methods: This was a prospective cross- sectional study conducted on 172 patients who underwent blood and blood component transfusion. Hb concentration <7g/dL was determined to be an indication for blood product transfusion.Results: In this study the most common indication for blood transfusion was antenatal patient with anemia (32.8%) followed by ruptured ectopic pregnancy (19.5%) and postpartum hemorrhage (18.8%). Amongst gynecological patients, the most common cause for transfusion was abnormal uterine bleeding (AUB) (61.4%). Majority patients were given single unit transfusion. Adverse reactions found in our study were not statistically significant.Conclusions: Therefore this study concludes that we still need to go a long way in order to train the medical fraternity at all levels to learn to identify the valid indications for transfusion and select appropriate component for management

Biomimetic synthesis of hybrid nanocomposite scaffolds by freeze-thawing and freeze-drying

The aim of this study is to biomimetically synthesize hydroxyapatite - hydrophilic polymer scaffolds for biomedical applications. This organic-inorganic hybrid has been structurally characterized and reveals a good microstructural control as seen by the SEM analysis and the nanosize of the particulates is confirmed by AFM microscopy. The characterization of such nano-structured composites would allow researchers to design new systems, tailoring properties for different applications. © Indian Academy of Sciences

Forecasting 2016 US Presidential Elections Using Factor Analysis and Regression Model

The paper categorizes factors responsible for forecasting the outcome of U.S. presidential election 2016 using factor analysis, which groups the various economic and non-economic parameters based on the correlation among them. The major economic factor significant in 2016 US presidential election is the growth of the economy, and the ‘anti-incumbency factor that signifies how long the incumbent party has been controlling the White House is found to be an important non-economic factor likely to play a dominant role in the election. The dependent variables considered are the vote shares of the nominees of the incumbent and the non-incumbent majority party candidates. The forecast is calculated by running a regression of the significant factors, obtained through factor analysis technique, on the incumbent party vote share as well as on the non-incumbent party vote share. The proposed models forecast the vote share of Democrat candidate Mrs. Hillary Clinton to be 45.59% with a standard error of ±2.32% and that of Republican candidate Mr. Donald Trump to be 39.51% with a standard error of ±3.87%. Hence, the models built in the paper signal a comfortable margin of victory for the Presidential nominee of the incumbent party, Hillary Clinton. The study re-establishes the notion that the non-economic factors have a greater influence on the outcomes of election as compared to the economic factors, as some of the important economic factors such as inflation and unemployment rate failed to establish their significance

Isolation and identification of carotenoid-producing yeast and evaluation of antimalarial activity of the extracted carotenoid(s) against P. falciparum

Plasmodial resistance to a variety of plant-based antimalarial drugs has led toward the discovery of more effective antimalarial compounds having chemical or biological origin. Since natural compounds are considered as safer drugs, in this study, yeast strains were identified and compared for the production of carotenoids that are well-known antioxidants and this metabolite was tested for its antiparasitic activity. Plasmodium falciparum 3D7 strain was selected as the target parasite for evaluation of antimalarial activity of yeast carotenoids using in vitro studies. Data were analyzed by FACS (fluorescence-activated cell sorter) and counted via gold standard Giemsa-stained smears. The extracted yeast carotenoids showed a profound inhibitory effect at a concentration of 10–3 µg/µl and 10−4 µg/µl when compared to β- carotene as control. SYBR Green1 fluorescent dye was used to confirm the decrease in parasitaemia at given range of concentration. Egress assay results suggested that treated parasite remained stalled at schizont stage with constricted morphology and were darkly stained. Non-toxicity of carotenoids on erythrocytes and on human liver hepatocellular carcinoma cells (HepG2 cells) was shown at a given concentration. This report provides strong evidence for antimalarial effects of extracted yeast carotenoids, which can be produced via a sustainable and cost-effective strategy and may be scaled up for industrial application

Understanding the Role of PknJ in Mycobacterium tuberculosis: Biochemical Characterization and Identification of Novel Substrate Pyruvate Kinase A

Reversible protein phosphorylation is a prevalent signaling mechanism which modulates cellular metabolism in response to changing environmental conditions. In this study, we focus on previously uncharacterized Mycobacterium tuberculosis Ser/Thr protein kinase (STPK) PknJ, a putative transmembrane protein. PknJ is shown to possess autophosphorylation activity and is also found to be capable of carrying out phosphorylation on the artificial substrate myelin basic protein (MyBP). Previous studies have shown that the autophosphorylation activity of M. tuberculosis STPKs is dependent on the conserved residues in the activation loop. However, our results show that apart from the conventional conserved residues, additional residues in the activation loop may also play a crucial role in kinase activation. Further characterization of PknJ reveals that the kinase utilizes unusual ions (Ni2+, Co2+) as cofactors, thus hinting at a novel mechanism for PknJ activation. Additionally, as shown for other STPKs, we observe that PknJ possesses the capability to dimerize. In order to elucidate the signal transduction cascade emanating from PknJ, the M. tuberculosis membrane-associated protein fraction is treated with the active kinase and glycolytic enzyme Pyruvate kinase A (mtPykA) is identified as one of the potential substrates of PknJ. The phospholabel is found to be localized on serine and threonine residue(s), with Ser37 identified as one of the sites of phosphorylation. Since Pyk is known to catalyze the last step of glycolysis, our study shows that the fundamental pathways such as glycolysis can also be governed by STPK-mediated signaling