Differences in uptake kinetics of ammonium and nitrate in legumes and cereals

In a greenhouse experiment, influx isotherms were obtained for nitrate and ammonium from pigeonpeas cv. ICPL 87, chickpea cv. K850, groundnut cv. NCAC 17090, sorghum cv. CSH5, Pennisetum glaucum cv. WC 75 and maize cv. Ganga 5. The transition in influx isotherms for both N sources was within the concentration range (0.05-2.5 mM) tested. There were significant differences in Km and Vmax for ammonium between legumes and cereals. The difference in the kinetic properties for nitrate uptake between the 2 groups of plants only became apparent at the highest concentration tested. Legumes translocated absorbed nitrate and ammonium to shoots more rapidly than cereal

Role of the dimerized gap due to anion ordering in spin-density wave phase of (TMTSF)2_2ClO4_4 at high magnetic fields

Magnetoresistance measurements have been carried out along the highly conducting a axis in the FISDW phase of hydrogened and deuterated (TMTSF)$_2$ClO$_4$ for various cooling rates through the anion ordering temperature. With increasing the cooling rate, a) the high field phase boundary $\beta_{\rm {HI}}$, observed at 27 T in hydrogened samples for slowly cooled, is shifted towards a lower field, b) the last semimetallic SDW phase below $\beta_{\rm {HI}}$ is suppressed, and c) the FISDW insulating phase above $\beta_{\rm {HI}}$ is enhanced in both salts. The cooling rate dependence of the FISDW transition and of $\beta_{\rm {HI}}$ in both salts can be explained by taking into account the peculiar SDW nesting vector stabilized by the dimerized gap due to anion ordering.Comment: 6pages,6figures(EPS), accepted for publication in PR

Magnetic irreversibility and Verwey transition in nano-crystalline bacterial magnetite

The magnetic properties of biologically-produced magnetite nanocrystals biomineralized by four different magnetotactic bacteria were compared to those of synthetic magnetite nanocrystals and large, high quality single crystals. The magnetic feature at the Verwey temperature, $T_{V}$, was clearly seen in all nanocrystals, although its sharpness depended on the shape of individual nanoparticles and whether or not the particles were arranged in magnetosome chains. The transition was broader in the individual superparamagnetic nanoparticles for which $T_{B}<T_{V}$, where $T_{B}$ is the superparamagnetic blocking temperature. For the nanocrystals organized in chains, the effective blocking temperature $T_{B}>T_{V}$ and the Verwey transition is sharply defined. No correlation between the particle size and $T_{V}$ was found. Furthermore, measurements of $M(H,T,time)$ suggest that magnetosome chains behave as long magnetic dipoles where the local magnetic field is directed along the chain and this result confirms that time-logarithmic magnetic relaxation is due to the collective (dipolar) nature of the barrier for magnetic moment reorientation

Response Of The Pigeonpea (Cajanus Cajan (L.) Millspaugh) To Nitrogen Application And Temporary Waterlogging

Short-duration pigeonpea (Cajanus cajan (L.) Millspaugh, cv. ICPL 87)) responded to applied N by increasing its shoot and rwt growth in a Vertisol field at ICRISAT Center in India. However. growth of shoot and roots was impaired and N concentration in leaf was decreased by short-ten (three days) waterlogging. During the recovery phase pigeonpa developed new adventitious rwts around the base of tap root with new nodules. Therefore waterlogged pigeonpea had higher total nodule activity than control plants and there were no differences in N concentration in ieaf at 40 days after the termination of waterlogging

Rooting Behavior Of Intercropped Pigeonpea (Cajanus Cajan (L.) Millspaugh) And Sorghum (Sorghum Bicolor (L.) Moench)

The motlng pmnk of lndhrldual plgeonpea and sorghum plants were compared In monocmpplng and Intercmpplng, under different planting densltles, by use of a slmple dmulatlon appmach. Plgeonpea dld not show any characteristic advantages of root development over sorghum, pmbably due to the presence of a hard stony layer below 30 cm whlch consequently conflned roo1 pmllferatlon wlthln the sutfam layer of 8011. The rootlng depth was unaffected by the cropplng pattern. The root pmllfetatlon near the plant base Increased wlth plant age and was severely reduced by lntercmpplng In case of plgeonpea The lntercmpped sorghum had less mots lnltlally but attained a slmllar denslty as monocmpped sorghum at later stages. It Is demonstrated that root development Is conslderably affected by the planting denslty

Isoprene oxidation products are a significant atmospheric aerosol component

International audienceGlycolaldehyde, hydroxyacetone, and methylglyoxal, which are known isoprene oxidation products, were collected during two field experiments using an annular denuder sampling system and compared to a model calculation. The compounds in gas and aerosol phases were determined during both experiments. Global variation and distribution of the aerosol mass contribution of the compounds were predicted using the measurements, the box model results, and gas-phase concentrations and humidity simulated by a global 3-D model. Here we report the estimates of a global annual contribution of 35 (10?120) Tg of aerosol organic matter from isoprene

Molecular line mapping of the giant molecular cloud associated with RCW 106 - II. Column density and dynamical state of the clumps

We present a fully sampled C^{18}O (1-0) map towards the southern giant molecular cloud (GMC) associated with the HII region RCW 106, and use it in combination with previous ^{13}CO (1-0) mapping to estimate the gas column density as a function of position and velocity. We find localized regions of significant ^{13}CO optical depth in the northern part of the cloud, with several of the high-opacity clouds in this region likely associated with a limb-brightened shell around the HII region G333.6-0.2. Optical depth corrections broaden the distribution of column densities in the cloud, yielding a log-normal distribution as predicted by simulations of turbulence. Decomposing the ^{13}CO and C^{18}O data cubes into clumps, we find relatively weak correlations between size and linewidth, and a more sensitive dependence of luminosity on size than would be predicted by a constant average column density. The clump mass spectrum has a slope near -1.7, consistent with previous studies. The most massive clumps appear to have gravitational binding energies well in excess of virial equilibrium; we discuss possible explanations, which include magnetic support and neglect of time-varying surface terms in the virial theorem. Unlike molecular clouds as a whole, the clumps within the RCW 106 GMC, while elongated, appear to show random orientations with respect to the Galactic plane.Comment: 17 pages, to appear in MNRA

Axial-flexural coupled vibration and buckling of composite beams using sinusoidal shear deformation theory

A finite element model based on sinusoidal shear deformation theory is developed to study vibration and buckling analysis of composite beams with arbitrary lay-ups. This theory satisfies the zero traction boundary conditions on the top and bottom surfaces of beam without using shear correction factors. Besides, it has strong similarity with Euler–Bernoulli beam theory in some aspects such as governing equations, boundary conditions, and stress resultant expressions. By using Hamilton’s principle, governing equations of motion are derived. A displacement-based one-dimensional finite element model is developed to solve the problem. Numerical results for cross-ply and angle-ply composite beams are obtained as special cases and are compared with other solutions available in the literature. A variety of parametric studies are conducted to demonstrate the effect of fiber orientation and modulus ratio on the natural frequencies, critical buckling loads, and load-frequency curves as well as corresponding mode shapes of composite beams