Broadband modulation of light by using an electro-optic polymer

A major challenge to increasing bandwidth in optical telecommunications is to encode electronic signals onto a lightwave carrier by modulating the light up to very fast rates. Polymer electro-optic materials have the necessary properties to function in photonic devices beyond the 40-GHz bandwidth currently available. An appropriate choice of polymers is shown to effectively eliminate the factors contributing to an optical modulator's decay in the high-frequency response. The resulting device modulates light with a bandwidth of 150 to 200 GHz and produces detectable modulation signal at 1.6 THz. These rates are faster than anticipated bandwidth requirements for the foreseeable future.     

Hematological and pathological effects of chromium toxicosis in the freshwater fish,Barbus conchonius Ham

Experimental exposure to Cr(VI) induced anomalies in the peripheral blood and tissues of a freshwater fish, Barbus conchonius. Clinical findings in the blood corpuscles included swelling of erythrocytes, numerous circulating polychromatophils, and vacuolation of large lymphocytes during acute exposure. Poikilocytosis, severe cytoplasmic vacuolation and deterioration of cytoplasmic membrane in erythrocytes occurred following chronic exposure. Significant polycythemia with collateral rise in Hb and Hct were manifest in the acutely intoxicated fish. By contrast, chronic exposure caused marked erythropenia and an accompanying reduction in Hb and Hct values. Leucocyte subpopulations showed an initial rise and then a fall in the thrombocytes together with a significant lymphocytosis, neutropenia, and basophilia. Pathological changes were observed in the gills, kidneys, and liver of Cr-exposed fish.     

Heterotic effects of wheat-rye chromosomal translocations on agronomic traits of hybrid wheat (Triticum aestivum L.) under an adequate moisture regime

Translocated chromosomes T1BL⋅1RS and T1AL⋅1RS have been widely used in many wheat (Triticum aestivum L.) breeding programs to develop high yielding cultivars. The objective of this study was to evaluate the heterotic effects of T1BL⋅1RS + T1AL⋅1RS, T1BL⋅1RS, and T1AL⋅1RS on yield and yield components of hybrid wheat grown under adequate moisture regimes. Thirteen hybrid wheats and seven parents with different chromosome constitutions relative to T1AL⋅1RS and T1BL⋅1RS were evaluated in a randomized complete block design. Variable performance was observed among the hybrids tested. Two of the three hybrids with T1BL⋅1RS + T1AL⋅1RS, produced 25.26% and 44.64% more grain than the hybrids with only T1BL⋅1RS. This was due to increased biomass, harvest index (HI) and spike density. However, the combination of these two translocations resulted in reduced kernels/spike, spikelets/spike and spike length compared to the T1BL⋅1R Stranslocation alone. When comparing closely related parents, the parent with T1AL⋅1RS produced 23.51% more grain yield than the non-translocated parent. The presence of T1AL⋅1RS resulted in 10.37% heterotic advantage for yield due to increased biomass, KW, and spike density. When the two wheat-rye translocated chromosomes are present in the same hybrid, T1AL⋅1RS seems to have a positive effect on yield through spike density and HI, but masks the effects of T1BL⋅1RS for some agronomic traits. This revised version was published online in August 2006 with corrections to the Cover Date.     

Quantitative and molecular characterization of heat tolerance in hexaploid wheat

Understanding the genetic basis of tolerance to high temperature is important for improving the productivity of wheat (Triticum aestivum L.) in regions where the stress occurs. The objective of this study was to estimate inheritance of heat tolerance and the minimum number of genes for the trait in bread wheat by combining quantitative genetic estimates and molecular marker analyses. Two cultivars, Ventnor (heat-tolerant) and Karl92 (heat-susceptible), were crossed to produce F₁, F₂, and F₃populations, and their grain-filling duration (GFD) at 30/25 ^°C 16/8 h day/night was determined as a measure of heat tolerance. Distribution of GFD in the F₁ and F₂ populations followed the normal model (χ², p > 0.10). A minimum of 1.4 genes with both additive and dominance effects, broad-sense heritability of 80%, and realized heritability of 96%for GFD were determined from F₂ and F₃ populations. Products from 59primer pairs among 232 simple sequence repeat (SSR) pairs were polymorphic between the parents. Two markers, Xgwm11 andXgwm293, were linked to GFD by quantitative trait loci (QTL) analysis of the F₂ population. The Xgwm11-linked QTL had only additive gene action and contributed 11% to the total phenotypic variation in GFD in the F₂population, whereas the Xgwm293-linked QTL had both additive and dominance action and contributed 12% to the total variation in GFD. The results demonstrated that heat tolerance of common wheat is controlled by multiple genes and suggested that marker-assisted selection with microsatellite primers might be useful for developing improved cultivars. This revised version was published online in August 2006 with corrections to the Cover Date.     

Brucellosis in India: results of a collaborative workshop to define One Health priorities

Tropical Animal Health and Production - Brucellosis is an important zoonosis worldwide. In livestock, it frequently causes chronic disease with reproductive failures that contribute to production...