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Description of a new species of Caridina H. M. Edwards from the hill streams of southern Western Ghats, Tamil Nadu, India

The paper describes a new species, Caridina mathiassi sp. nov., from the hill streams of Mahendragiri Estate, part of southern Western Ghats, Kanyakumari District, Tamil Nadu, India (8o 27’ 32.27" N and 77o 23’ 32.50" E) collected during summer months of 1999 and 2000. This species is abundant and closely related to Caridina jalihali Mariappan and Richard, 2006 and Caridina gurneyi Jalihal et al., 1984. The diagnosis of the species include: shrimps of genus Caridina having a moderately long rostrum with 11-20 dorsal (4-6 post-orbital) and 2-7 ventral teeth; telson not ending in a median spine but with 4-10 spinules at distal and 3-5 pairs of spines at dorsal regions; carpus of first pereiopod deeply excavated anteriorly; fourth pereiopod with merus having 2-4, carpus having 1 large and 3-5 small spines and dactylus ending in a sharp spine and 5-7 spinules; fifth pereiopod with merus having 2-4, carpus with 1 large and sometimes 3-4 small spines and dactylus having 30-40 spinules; endopod of first pleopod with long appendix interna subterminal, curved inwards; appendix masculina double the size of appendix interna or a little longer of male second pleopod; diaeresis of uropod with 16-22 spines; size of eggs ranging from 0.53-0.61 X 0.86-1.04 mm and fecundity ranging from 122-181

Optimal configuration of microstructure in ferroelectric materials by stochastic optimization

An optimization procedure determining the ideal configuration at the microstructural level of ferroelectric (FE) materials is applied to maximize piezoelectricity. Piezoelectricity in ceramic FEs differ significantly from that of single crystals because of the presence of crystallites (grains) possessing crystallographic axes aligned imperfectly. The piezoelectric properties of a polycrystalline (ceramic) FE is inextricably related to the grain orientation distribution (texture). The set of combination of variables, known as solution space, which dictates the texture of a ceramic is unlimited and hence the choice of the optimal solution which maximizes the piezoelectricity is complicated. Thus a stochastic global optimization combined with homogenization is employed for the identification of the optimal granular configuration of the FE ceramic microstructure with optimum piezoelectric properties. The macroscopic equilibrium piezoelectric properties of polycrystalline FE is calculated using mathematical homogenization at each iteration step. The configuration of grains characterised by its orientations at each iteration is generated using a randomly selected set of orientation distribution parameters. Apparent enhancement of piezoelectric coefficient $d_{33}$ is observed in an optimally oriented BaTiO$_3$ single crystal. A configuration of crystallites, simultaneously constraining the orientation distribution of the c-axis (polar axis) while incorporating ab-plane randomness, which would multiply the overall piezoelectricity in ceramic BaTiO$_{3}$ is also identified. The orientation distribution of the c-axes is found to be a narrow Gaussian distribution centred around ${45^\circ}$. The piezoelectric coefficient in such a ceramic is found to be nearly three times as that of the single crystal.Comment: 11 pages, 7 figure

Small-angle neutron scattering studies on water soluble complexes of poly(ethylene glycol)-based cationic random copolymer and SDS

The interaction of cationic random copolymers of methoxy poly(ethylene glycol) monomethacrylate and (3-(methacryloylamino)propyl) trimethylammonium chloride with oppositely charged surfactant, sodium dodecyl sulphate, and the influence of surfactant association on the polymer conformation have been investigated by small-angle neutron scattering. SANS data showed a positive indication of the formation of RCPSDS complexes. Even though the complete structure of the polyion complexes could not be ascertained, the results obtained give us the information on the local structure in these polymer-surfactant systems. The data were analysed using the log-normal distribution of the polydispersed spherical aggregate model for the local structure in these complexes. For all the systems the median radius and the polydispersity were found to be in the range of 20 ± 2 Å and 0.6 ± 0.05, respectively

Characteristics of VHF radiowave scintillations over a solar cycle (1983?1993) at a low-latitude station: Waltair (17.7°N, 83.3°E)

International audienceThe characteristics of VHF radiowave scintillations at 244 MHz (FLEETSAT) during a complete solar cycle (1983?93) at a low-latitude station, Waltair (17.7°N, 83.3°E), are presented. The occurrence of night-time scintillations shows equinoctial maxima and summer minima in all the epochs of solar activity, and follows the solar activity. The daytime scintillation occurrence is negatively correlated with the solar activity and shows maximum occurrence during the summer months in a period of low solar activity. The occurrence of night-time scintillations is inhibited during disturbed days of high solar activity and enhanced during low solar activity

Leukocyte- and Platelet-Derived Microvesicle Interactions following In Vitro and In Vivo Activation of Toll-Like Receptor 4 by Lipopolysaccharide

BACKGROUND: Pro-coagulant membrane microvesicles (MV) derived from platelets and leukocytes are shed into the circulation following receptor-mediated activation, cell-cell interaction, and apoptosis. Platelets are sentinel markers of toll-like receptor 4 (TLR4) activation. Experiments were designed to evaluate the time course and mechanism of direct interactions between platelets and leukocytes following acute activation of TLR4 by bacterial lipopolysaccharide (LPS). METHODOLOGY/PRINCIPAL FINDINGS: Blood from age-matched male and female wild type (WT) and TLR4 gene deleted (dTLR4) mice was incubated with ultra-pure E. coli LPS (500 ng/ml) for up to one hour. At designated periods, leukocyte antigen positive platelets, platelet antigen positive leukocytes and cell-derived MV were quantified by flow cytometry. Numbers of platelet- or leukocyte-derived MV did not increase within one hour following in vitro exposure of blood to LPS. However, with LPS stimulation numbers of platelets staining positive for both platelet- and leukocyte-specific antigens increased in blood derived from WT but not dTLR4 mice. This effect was blocked by inhibition of TLR4 signaling mediated by My88 and TRIF. Seven days after a single intravenous injection of LPS (500 ng/mouse or 20 ng/gm body wt) to WT mice, none of the platelets stained for leukocyte antigen. However, granulocytes, monocytes and apoptotic bodies stained positive for platelet antigens. CONCLUSIONS/SIGNIFICANCE: Within one hour of exposure to LPS, leukocytes exchange surface antigens with platelets through TLR4 activation. In vivo, leukocyte expression of platelet antigen is retained after a single exposure to LPS following turn over of the platelet pool. Acute expression of leukocyte antigen on platelets within one hour of exposure to LPS and the sustained expression of platelet antigen on leukocytes following a single acute exposure to LPS in vivo explains, in part, associations of platelets and leukocytes in response to bacterial infection and changes in thrombotic propensity of the blood

Marine Ecosystems Challenges and Opportunities (MECOS 09) Book of Abstracts

Marine ecosystems contain several unique qualities that set them apart from other ecosystems. Of the 89 elements occurring in nature, the presence of 80 has been confirmed in seawater. It is perhaps true that the remaining 9 elements are also present, but in concentrations too small to be detected. This wide range of substances dissolved in seawater has placed the marine organisms in a more advantageous position than their freshwater counterparts. These elements provide the essential materials required for the synthesis of all the basic nourishments of the body including the skeletal support of marine animals. In the terrestrial ecosystems, the physical boundaries are well marked and environmental variabilities are rather wide. The terrestrial organisms and ecosystems have developed internal mechanisms to cope up with variabilities. In contrast, in the marine ecosystems, the physical variability is small and extends over very long time scales due to the large thermal capacity of the oceans and the long periods of exchange between deep and near shore waters. Consequently, the marine ecosystems are more vulnerable to large-scale environmental changes because they do not have the internal adaptability inherent in the terrestrial systems