The Current State of Solar Modeling

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.     

Surveillance and monitoring programmes in the control of rinderpest: A review

Tropical Animal Health and Production -     

In vitro Growth and Maturation of Caprine Oocytes

This study was conducted to culture in vitro caprine pre-antral follicles for determining the competence of growth and maturation of oocytes and establishing a suitable culture system for oocyte maturation from pre-antral follicles. Two different culture methods (microdrop and agar gel clot) were employed to culture caprine pre-antral follicles. The pre-antral follicles were isolated from prepubertal goat ovaries by treatment with collagenase and DNase. The isolated pre-antral follicles were cultured in basic culture medium for 9 days (for growth). And oocytes were cultured in maturation culture medium for another 2 days for maturation. The result demonstrated that the growth rate of oocytes cultured in microdrops was significantly (p < 0.05) higher than that in agar gel clots, whereas the viability of oocytes in microdrops was considerably (p < 0.05) lower than that in agar gel clots. The oocytes grew over 150 microm in diameter, and two of 151 oocytes cultured in microdrops yielded morphologically abnormal first polar bodies. However, the size of oocytes cultured in agar gel approached to 120 microm in diameter and no polar body was produced.     

Local Control of Microdomain Orientation in Diblock Copolymer Thin Films with Electric Fields

Local control of the domain orientation in diblock copolymer thin films can be obtained by the application of electric fields on micrometer-length scales. Thin films of an asymmetric polystyrene-polymethylmethacrylate diblock copolymer, with cylindrical polymethylmethacrylate microdomains, were spin-coated onto substrates previously patterned with planar electrodes. The substrates, 100-nanometer-thick silicon nitride membranes, allow direct observation of the electrodes and the copolymer domain structure by transmission electron microscopy. The cylinders aligned parallel to the electric field lines for fields exceeding 30 kilovolts per centimeter, after annealing at 250°C in an inert atmosphere for 24 hours. This technique could find application in nanostructure fabrication.     

Improved isolation of rinderpest virus in transformed bovine T lymphoblast cell lines.

Bovine T lymphoblast cell lines transformed by the protozoan Theileria parva were compared with bovine kidney (BK) and Vero cells for their ability to isolate various strains of rinderpest virus from tissues and infected secretions. All of the strains of rinderpest virus that were tested, including attenuated cell-culture, caprinised and lapinised vaccines, and both mild and virulent pathogenic strains, readily induced syncytial cytopathic effect (cpe) in T lymphoblasts. The cpe could often be detected within one day of inoculation of lymphoblasts, whereas it took three to 14 days to appear in Vero and BK cells. Using lymphoblasts it was possible to reisolate rinderpest virus from nine of 42 swabs collected from three cattle experimentally infected with an isolate from a recent outbreak of mild disease whereas the same swabs yielded only one reisolate on BK cells. It was also possible using the lymphoblasts to detect infectious virus in the ocular, nasal and oral secretions of goats and rabbits infected with caprinised and lapinised virus, respectively. Peste des petits ruminants virus appeared to grow as rapidly as rinderpest virus in the lymphoblasts whereas canine distemper virus readily induced cpe on first passage but less readily on subsequent passage. Measles virus induced relatively little cpe when inoculated into lymphoblasts and did not appear to passage in these cells. The lymphoblasts are easy to maintain in culture and since they rapidly recovered 11 isolates from 37 diagnostic samples could prove useful in laboratories carrying out rinderpest diagnosis.     

Use of vero cells for the isolation and propagation of malignant catarrhal fever virus

Summary Vero cells were compared with primary bovine thyroid (BTh) cultures for the isolation of malignant catarrhal fever virus from infected blood and tissues. Comparative titrations showed Vero cells detected only two-fold less infectivity in rabbit spleen suspensions than BTh cells. Twenty three of 32 bovine buffy coat cell preparations which were positive on BTh cells were all also positive on Vero cells. The cytopathic effects (CPE) of virus isolates in Vero cells consisted of syncytia and refractile cytomegalic cells which were as easy to recognise and developed as rapidly as CPE in BTh cells. Two laboratory strains of malignant catarrhal fever virus were readily adapted to and maintained by passage in Vero cells.

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El Uso De Celulas Vero Para El Aislamiento Y Propagacion Del Virus De La Fiebre Catarral Maligna

Resumen Se compararon las células Vero con cultivos de tiroides bovina primária, para el aislamiento del virus de la fiebre catarral maligna, proveniente de sangre infectada y tejidos. Titulaciones comparativas mostraron que las células Vero detectaron solamente dos factores menos de infectividad en suspensión de bazo de conejo, que las células de tiroides. Veintitres de 32 preparaciones de células buffy coat las cuales fueron positivas en células de tiroides, feuron tambien positivas en células Vero. El efecto citopático de aislamientos virales en células Vero consistió en sincitia y la aparición de células refractárias citomegálicas, las cuales fueron fáciles de reconocer y se desarrollaron tan rápidamente como el efecto citopático en células de la tiroides. Dos cepas de laboratorio del virus de la fiebre catarral maligna se adaptaron rápidamente y se mantuvieron mediante pasajes en células Vero.

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Emploi Des Cellules Vero Pour L'Isolement Et La Multiplication Du Virus Du Coryza Gangreneux (Malignant Catarrhal Fever)

Résumé Des cellules Vero ont été comparées avec des cultures primaires de thyro?de de bovin (BTh) pour isoler le virus de coryza gangréneux à partir de sang et de tissus infectés. Les titrages comparatifs ont montré que les cellules Vero n'ont pu détecter qu'une infectivité deux fois moindre dans les suspensions de rate de lapin que les cellules BTh. Sur 32 préparations de cellules de la lignée blanche obtenues par centrofixation (buffy coat), 23 étaient positives à la fois sur cellules BTh et sur cellules Vero. L'effet cytopathogène (cpe) des isolats de virus sur cellules Vero consistait en syncytium et en cellules cytomégaliques réfractiles aussi faciles à reconna?tre, et au développement aussi rapide que l'effet cytopathogène sur BTh. Deux souches de laboratoire du virus de la fièvre catarrhale maligne ont été immédiatement adaptées et mainteneues par passages sur cellules Vero.

     

The Seismic Structure of the Sun

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.     

Comparison of Different Glycerol and Egg Yolk Concentrations Added to Tris‐based Extender for the Collared Peccaries (Tayassu tajacu) Semen Freezing

This study aimed to evaluate various concentrations of egg yolk (5, 10, or 20%) in combination with different concentrations of glycerol (3% or 6%) added to a Tris‐based extender on the post‐thaw characteristics of sperm obtained from Tayassu tajacu. For this purpose, semen from 10 sexually male mature collared peccaries was collected by electroejaculation and evaluated for sperm motility, vigour, viability, morphology and functional membrane integrity. The ejaculates were initially extended in Tris‐fructose plus egg yolk (5%, 10% or 20%). After cooling, the semen was added to Tris‐egg yolk plus glycerol (6% or 12%), resulting in a final concentration of 3% or 6% glycerol of the extender. Straws were frozen using liquid nitrogen and thawed in a water bath at 37°C for 30 s. The frozen–thawed semen was evaluated as reported for fresh semen. After thawing, a significant decrease was verified for sperm motility and vigour, for all the samples in comparison with fresh semen. However, no differences were evidenced among treatments for any sperm characteristics evaluated (p > 0.05), except for the combination between 10% egg yolk and 6% glycerol, which provided the worst preservation of functional membrane integrity (p < 0.05). The interactions between higher concentrations of egg yolk (20%) and glycerol (6%) and also between lower concentrations of the same substances (5% egg yolk and 3% glycerol) added to the Tris‐based extender negatively affected the preservation of the normal sperm morphology after thawing (p < 0.05). In conclusion, the use of Tris‐based extender added to 10% or 20% egg yolk plus 3% glycerol is recommended for effective sperm cryopreservation in collared peccaries.