Aetiology and histopathology of bovine mastitis of espontaneous occurrence

Infectious bovine mastitis is responsible for serious economic losses in dairy cattle breeding. Information about the damages caused by micro-organisms is of great interest and importance. The purpose of the present study was to report on the microbiological and histopathological aspects of the mammary parenchymas of slaughtered dairy cows. A total of 184 mammary glands were examined and samples of mammary parenchyma were collected for microbiological and histopathological examinations. Micro-organisms were isolated from 69.6% samples; 23 (12.5%) of the 184 samples did not show histological changes; inflammatory response was observed in 56 (30.4%) samples; inflammatory response and repair were present in 82 (44.6%) samples; repair process was verified in 23 (12.5%) of the mammary glands. Coagulase-negative Staphylococci were observed in 53.8% of the samples followed by coagulase-positive Staphylococci (7.6%), Prototheca sp. (2.2%) and Streptococcus dysgalactiae (1.6%). Coagulase-negative Staphylococci and coagulase-positive Staphylococci were associated mainly to chronic inflammatory response and chronic inflammatory response and repair. Samples from which no micro-organisms were isolated (n = 56) had no histological changes in 82.6% of the cases. These results were higher (P < 0.05) when compared to the samples with micro-organisms and without histological changes (17.4%).     

GONG Observations of Solar Surface Flows

Doppler velocity observations obtained by the Global Oscillation Network Group (GONG) instruments directly measure the nearly steady flows in the solar photosphere. The sun's differential rotation is accurately determined from single observations. The rotation profile with respect to latitude agrees well with previous measures, but it also shows a slight north-south asymmetry. Rotation profiles averaged over 27-day rotations of the sun reveal the torsional oscillation signal-weak, jetlike features, with amplitudes of 5 meters per second, that are associated with the sunspot latitude activity belts. A meridional circulation with a poleward flow of about 20 meters per second is also evident. Several characteristics of the surface flows suggest the presence of large convection cells.     

Domain dynamics during ferroelectric switching

The utility of ferroelectric materials stems from the ability to nucleate and move polarized domains using an electric field. To understand the mechanisms of polarization switching, structural characterization at the nanoscale is required. We used aberration-corrected transmission electron microscopy to follow the kinetics and dynamics of ferroelectric switching at millisecond temporal and subangstrom spatial resolution in an epitaxial bilayer of an antiferromagnetic ferroelectric (BiFeO(3)) on a ferromagnetic electrode (La(0.7)Sr(0.3)MnO(3)). We observed localized nucleation events at the electrode interface, domain wall pinning on point defects, and the formation of ferroelectric domains localized to the ferroelectric and ferromagnetic interface. These results show how defects and interfaces impede full ferroelectric switching of a thin film.     

Integration of environmental, agronomic, and economic aspects of fertilizer management

Nitrogen fertilization is a substantial source of nitrogen-containing trace gases that have both regional and global consequences. In the intensive wheat systems of Mexico, typical fertilization practices lead to extremely high fluxes of nitrous oxide (N2O) and nitric oxide (NO). In experiments, lower rates of nitrogen fertilizer, applied later in the crop cycle, reduced the loss of nitrogen without affecting yield and grain quality. Economic analyses projected this alternative practice to save 12 to 17 percent of after-tax profits. A knowledge-intensive approach to fertilizer management can substitute for higher levels of inputs, saving farmers money and reducing environmental costs.