Coherent Flow Structures over Scour Marks Generated by Obstacles of Different Shapes

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Endozoochorus Seed Dispersal by Jalauni Sheep in Tropical Climate: Recovery and Germinability under Natural Pasture Grazing

Herbivores can play an important role in seed dispersal. Climate, available vegetation for grazing, pasture situation can determine the seed dispersal trends by the grazing animals. Tropical climate of India with wide climatic variation leads to fluctuating herbage quality and available biomass. Ruminants spread plants through fecal pellets after grazing at one place and fecal voiding at another. Herbivores can play an important role in seed dispersal. Climate, available vegetation for grazing, pasture situation can determine the seed dispersal trends by the grazing animals. Tropical climate of India with wide climatic variation leads to fluctuating herbage quality and available biomass. Ruminants spread plants through fecal pellets after grazing at one place and fecal voiding at another. Sheep have narrow mouths and flexible lips than other ruminants that lead them selective grazing on palatable forage (Grande et al., 2013). During dry season and hearse climate they are forced to graze on dried up grasses and twigs and thereby consume mature seed and seed those not digested passes through fecal pellets that has endozoochorus characteristics. Herbivores can affect vegetation by driving dispersal patterns of plants or zoochory (Fenner and Thompson, 2005). For grazing animal, germination success of seed from fecal pellets determined by the eating rate of animal under grazing along with palatable plants (Pakeman et al., 2002) and the solvability of seed in the digestive system. Tropical climate pasture dominated by different grass species along with weeds has bushes too for browsing. During late winter to dry season between January to May, animal compelled to graze on available dry grasses and weeds and those seed disperse through pelleting in other areas. Information on this regard is very rare to compare and present studies conducted at tropical climate of India during January to May

Observable signals in a string inspired axion-dilaton background and Randall-Sundrum scenario

Rotation angle of the plane of polarization of the distant galactic radio waves has been estimated in a string inspired axion-dilaton background. It is found that the axion,dual to the field strength of the second rank antisymmetric massless Kalb-Ramond field in the string spectrum, produces a wavelength independent optical rotation which is much larger than that produced by the dilaton. Detection of such rotation has been reported in some recent cosmological experiments. The observed value has been compared with our estimated theoretical value following various cosmological constraints. The effects of warped extra dimensions in a braneworld scenario on such an optical rotation have been investigated.Comment: 17 Pages, Latex, article revised, To appear in Physical Review

Production of Aluminium-Silicon Carbide Cast Particle Composites Without Magnesium

To produce Al matrix cast particle composites, wettability of the ceramic particles by liquid Al is essential. To improve wettability, elements such as Mg, Ce etc. are added into Al alloy prior to incorporation of the ceramic particles. In other methods,ceramic particles are incorporated into solid-liquid slurry of Al alloy: metalceramic powder compacts are slowly dissolved into the Al alloy or particles are preheated before incorporation into Al alloy.In the present study, silicon carbide and alumina particles were mixed with Al-Cu (50:50) piaster alloy powder in a required proportion to produce Al-4.5 Cu alloy- 15 wt% particle composites by vortex method. Success was achieved to incorporate SiC particles in an Al melt without Mg. whereas in case of alumina particles, the viscosity of the melt was too high after addition of about half of the required amount of particles. The fluidity of the Al alloy-SIC composite melt was sufficient to pour in graphite moulds. The mechanism of this novel approach of production of cast ceramic particle composites by vortex method without Mg is discussed

Constraining the Randall-Sundrum modulus in the light of recent PVLAS data

Recent PVLAS data put stringent constraints on the measurement of birefringence and dichroism of electromagnetic waves travelling in a constant and homogeneous magnetic field. There have been theoretical predictions in favour of such phenomena when appropriate axion-electromagnetic coupling is assumed. Origin of such a coupling can be traced in a low energy string action from the requirement of quantum consistency. The resulting couplings in such models are an artifact of the compactification of the extra dimensions present inevitably in a string scenario. The moduli parameters which encode the compact manifold therefore play a crucial role in determining the axion-photon coupling. In this work we examine the possible bounds on the value of compact modulus that emerge from the experimental limits on the coupling obtained from the PVLAS data. In particular we focus into the Randall-Sundrum (RS) type of warped geometry model whose modulus parameter is already restricted from the requirement of the resolution of gauge hierarchy problem in connection with the mass of the Higgs. We explore the bound on the modulus for a wide range of the axion mass for both the birefringence and the dichroism data in PVLAS. We show that the proposed value of the modulus in the RS scenario can only be accommodated for axion mass \gsim 0.3 eV.Comment: 26 pages, 1 figure, LaTex; added references, typos corrected. Minor changes in the text, a comment added in the Conclusio

Effect of Sublethal Concentration of Malathion Insecticide on Innate Immune System, Immune Function and Hemocytes of Adult Drosophila melanogaster

Invertebrate organisms mostly have innate immune system. Hemocytes are the immune cells of the innate immunity in invertebrates. Our study was designed to observe the effect of malathion insecticide on the innate immune system, immune function and hemocytes of Drosophila melanogaster. A hemocytometer was used for total count of hemocytes which showed a reduced percentage of live cells (from 91.63% to 44.57%) due to the treatment. For differential count, the hemolymph was spread as a smear on a clean grease free slide. It was observed that the plasmatocyte count considerably decreased under the effect of malathion (from 78% to 44.66%). Lamellocytes also showed a decline in their number (from 18.33% to 12.61%). But, a trivial increase (from 3.67% to 3.98%) in crystal cell count was recorded. Our result suggests that malathion has mostly negative effect on hemocytes. This study could help in understanding of insect defense mechanism against such hazardous chemicals. Additionally, the function of human macrophages is analogous to the function of plasmatocytes. Hence, this work could possibly aid us in studying the response of human immune cells against organophosphates like malathion