3,848 research outputs found
Alterations in sperm characteristics of follicle-stimulating hormone (FSH)-immunized men are similar to those of FSH-deprived infertile male bonnet monkeys
The quality of sperm ejaculated by bonnet monkeys and normal, healthy proven fertile volunteer men, both actively immunized with ovine follicle-stimulating hormone (oFSH), was examined at different times of study for chromatin packaging and acrosomal glycoprotein concentration by flow cytometry. Susceptibility of sperm nuclear DNA to dithiothreitol (DTT)-induced decondensation, as measured by ethidium bromide binding, was markedly high compared with values at day 0 in men and monkeys during periods when FSH antibody titer was high. Sperm chromatin structure assay yields alphat values, which is another index of chromatin packaging. Higher alphat values, signifying poor packaging, occurred in both species following immunization with heterologous pituitary FSH. The binding of fluorosceinated pisum sativum agglutinin (PSA-FITC) to acrosome of sperm of monkeys and men was significantly low, compared with values at day 0 (control) during periods when cross-reactive FSH antibody titer was high and endogenous FSH was not detectable. Blockade of FSH function in monkeys by active immunization with a recombinant oFSH receptor protein corresponding to a naturally occurring messenger RNA (mRNA) also resulted in production of sperm with similar defects in chromatin packaging and reduced acrosomal glycoprotein concentration. Thus, it appears that in monkeys and men, lack of FSH signaling results in production of sperm that exhibit defective chromatin packaging and reduction in acrosomal glycoprotein content. These characteristics are similar to that exhibited by sperm of some class of infertile men. Interestingly, these alterations in sperm quality occur well ahead of decreased sperm counts in the ejaculate
A Comparison of Corrosion Behavior of Copper and Its Alloy in Pongamia pinnata Oil at Different Conditions
Vegetable oils are promising substitutes for petrodiesel as they can be produced from numerous oil seed crops that can be cultivated anywhere and have high energy contents, exhibiting clean combustion behavior with zero CO2 emission and negligible SO2 generation. The impact of biofuel on the corrosion of various industrial metals is a challenge for using biofuel as automotive fuel. Fuel comes in contact with a wide variety of metallic materials under different temperatures, velocities, and loads thereby causing corrosion during storage and flow of fuel. Hence, the present investigation compares the corrosion rates of copper and brass in Pongamia pinnata oil (O100), 3% NaCl, and oil blend with NaCl (O99) obtained by static immersion test and using rotating cage. The corrosivity and conductivity of the test media are positively correlated. This study suggested that the corrosivity of copper is higher than brass in Pongamia pinnata oil (PO)
Coulomb Interactions and Nanoscale Electronic Inhomogeneities in Manganites
We address the issue of endemic electronic inhomogeneities in manganites
using extensive simulations on a new model with Coulomb interactions amongst
two electronic fluids, one localized (polaronic), the other extended
(band-like), and dopant ions. The long range Coulomb interactions frustrate
phase separation induced by the strong on site repulsion between the fluids. A
single quantum phase ensues which is intrinsically and strongly inhomogeneous
at a nano-scale, but homogeneous on meso-scales, with many characteristics
(including colossal responses)that agree with experiments. This, we argue, is
the origin of nanoscale inhomogeneities in manganites, rather than phase
competition and disorder related effects as often proposed.Comment: 4 pages, 3 figure
Studies on site specific nutrient management (SSNM) on hybrid sunflower seed production in Southern Karnataka
A field experiment was conducted at the Main Research Station, University of Agricultural Sciences, Hebbal, Bangalore, to know the effect of Site Specific Nutrient Management (SSNM) on growth (plant height (cm), Leaf area (cm2 ), leaf area index (LAI) and dry matter production (g plant1 ) and yield (capitulum diameter (cm), No. of filled seeds, 1000 seed weight (g) and seed yield (kg ha-1 ) of hybrid sunflower seed production. The study indicated that significantly higher growth parameters viz., plant height (155.4 cm), leaf area (1293.10cm-2 ), leaf area index (0.69) and total dry matter accumulation (88.16 g plant-1 ) were recorded with SSNM for 1.2 tons ha-1 + Farm Yard Manure (FYM) as compared to recommended practice (Recommended Dose of Fertilizer 62.50:75:62.50 kg NPK ha-1 ). The application of fertilizers based on SSNM for a target yield of 1.2 t ha-1 + FYM resulted in significantly higher yield and yield attributes compared to the only application of RDF + FYM. The important yield parameters recorded that were significantly higher were viz., head diameter (19.89 cm) number of filled seeds per head (353.24), seed weight per plant (19.76 g), 1000 seed weight (43.72 g), hybrid seed yield (1003 kg ha-1 )
"Exhaustion" Physics in the Periodic Anderson Model using Iterated Perturbation Theory
We discuss the "exhaustion" problem in the context of the Periodic Anderson
Model using Iterated Perturbation Theory(IPT) within the Dynamical Mean Field
Theory. We find that, despite its limitations, IPT captures the exhaustion
physics, which manifests itself as a dramatic, strongly energy dependent
suppression of the effective Anderson impurity problem. As a consequence, low
energy scales in the lattice case are strongly suppressed compared to the
"Kondo scale" in the single-impurity picture. The IPT results are in
qualitative agreement with recent Quantum Monte Carlo results for the same
problem.Comment: 13 preprint pages including 1 table and 4 eps figures, replaced by
revised version, accepted for publication in Europhysics Letters, added
references and conten
Sound Velocity Anomaly at the Mott Transition: application to organic conductors and V2O3
Close to the Mott transition, lattice degrees of freedom react to the
softening of electron degrees of freedom. This results in a change of lattice
spacing, a diverging compressibility and a critical anomaly of the sound
velocity. These effects are investigated within a simple model, in the
framework of dynamical mean-field theory. The results compare favorably to
recent experiments on the layered organic \kappa-(BEDT-TTF)_2Cu[N(CN)_2]Cl
conductor . We predict that effects of a similar magnitude are expected for
V2O3, despite the much larger value of the elastic modulus of this material.Comment: New discussion of the relation between the sound-velocity and the
compressibility has been adde
Finite-temperature effects on the superfluid Bose-Einstein condensation of confined ultracold atoms in three-dimensional optical lattices
We discuss the finite-temperature phase diagram in the three-dimensional
Bose-Hubbard (BH) model in the strong correlation regime, relevant for
Bose-Einstein condensates in optical lattices, by employing a quantum rotor
approach. In systems with strong on site repulsive interactions, the rotor U(1)
phase variable dual to the local boson density emerges as an important
collective field. After establishing the connection between the rotor
construction and the the on--site interaction in the BH model the robust
effective action formalism is developed which allows us to study the superfluid
phase transition in various temperature--interaction regimes
Studies on the ontogenetic changes in the isozymes in Drosophila nasuta nasuta and Drosophila sulfurigaster neonasuta
Ontogenetic manifestations of four isozymes namely, acid phosphatase, alkaline phosphatase, α-esterase and β-esterase have been analysed in two closely related species- D. nasuta nasuta and D. sulfurigaster neonasuta. By adopting polyacrylamide gel electrophoretic technique 15 different developmental stages have been assayed. Electrophoretically homologous and distinct enzyme phenotypes for each enzyme system have been recognised in the two species under study. The implications of these findings are discussed
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