Trajectories of the mount st. Helens eruption plume

The plume of the major eruption of Mount St. Helens on 18 May 1980 penetrated 10 to 11 kilometers into the stratosphere, attaining heights of 22 to 23 kilometers. Wind shears rapidly converted the plume from an expanding vertical cone to a thin, slightly inclined lamina. The lamina was extruded zonally in the stratosphere as the lower part moved eastward at jet stream velocities, while the upper part slowly moved westward in the region of nonsteady transition from the westerlies to the summer stratospheric easterlies. Trajectories computed to position the NASA U-2 aircraft for sampling in the plume are described. Plume volume after 8 hours of strong volcanic emission is estimated at 2 x 10(6) cubic kilometers. Only about 1 percent of this volume is attributed to the volcano; the rest was entrained from the environment.     

Dated rock engravings from wonderwerk cave, South Africa

Radiocarbon dates associated with engraved stones from sealed archeological deposits at Wonderwerk Cave in the northern Cape Province indicate that rock engraving in South Africa is at least 10,000 years old.     

The detection of mastitis in individual quarters using electrical conductivity or somatic cell concentration

In this investigation electrical conductivity (EC) and somatic cell concentration (SCC) were compared in 3 herds for their ability to correctly identify the infection status of quarters. For EC, thresholds of 6.0 and 6.8 mS/cm were used and comparisons were made between quarters within each cow. The method of comparison between quarters was the same as that described by the manufacturers of the AHI Mastitis Detector. For SCC a threshold of 500 x 10(3) cells/ml was used. For both EC and SCC considerable variation was found between herds for sensitivity (the proportion of quarters infected with a major pathogen and detected as abnormal), and specificity (the proportion of quarters free from infection and detected as normal). The mean sensitivity and specificity of EC for the three herds was 49% and 79% respectively, whereas for SCC the means were 71% and 81% respectively. The variation in sensitivity and specificity of EC between herds was attributed to differences in the distribution of EC for quarters of similar infection status. It was concluded that these differences in herd EC precluded the use of pre-determined EC thresholds which were applicable for detecting mastitis in all herds.     

The cayo santiago primate colony

This is an account of the vicissitudes of the monkeys on Cayo Santiago. In it is described the relationship of the establishment of that primate colony to the development of the National Regional Primate Research Center Program in the United States and the Laboratory of Perinatal Physiology in Puerto Rico. The Cayo Santiago colony opened new aspects of biomedical research and stimulated the general use of nonhuman primates in behavioral as well as physiological investigations.     

The incidence of bruising in broiler flocks

1. The amount of down‐grading due to bruising in 55 flocks of broilers was investigated.

4. Bruising was classified as light or bad bruising and it is suggested that this division represents two distinct types of bruises with different causes.

3. The incidence of bruising was greater in female flocks than in male although the bruising in the former tended to be less severe.

4. The relationships between incidence of bruising and several variables associated with the flock and the environment were examined using regression analysis. The factors shown to have a significant influence on the incidence of bruising were: the age and mean weight of the flock, and the temperature and humidity on the day of processing.     

An age-related coagulation disorder associated with experimental infection with infectious bursal disease virus

Specific-pathogen-free White Leghorn chickens were inoculated with a field strain of infectious bursal disease virus. One group (A) was inoculated at 17 days after the chicks were hatched, and the other groups (C and E) were inoculated at posthatch day 42. Blood samples were obtained for determination of clotting times (whole blood recalcification, prothrombin, and activated partial thromboplastin times), virus-neutralizing antibody, and total hemolytic complement. There were significant increases in clotting times for groups C and E at 3 and 5 days after they were inoculated. There were no significant increases in clotting times at 3 days after inoculation in the group A chickens (inoculated at 17 days after hatching). There were no significant decreases in total complement activity in any of these chickens (groups A, C, and E). This study indicates that the mortality and clinical symptoms observed in chickens experimentally infected with infectious bursal disease virus may be associated with a clotting abnormality because it was noted only in chickens that developed severe clinical disease (inoculated at 42 days after hatching) and was not noted in chickens that remained clinically normal (inoculated at 17 days).     

Preliminary description of a potyvirus from Vallota speciosa

Apotyvirus, isolated fromVallota speciosa, is tentatively designatedVallota mosaic virus (VMV). VMV was easily transmissible in sap and could be transferred byMyzus persicae in a nonpersistent manner. Infection was symptomless inNicotiana clevelandii andSpinacia oleracea, whereasHyoscyamus niger, chenopodium quinoa, C. amaranticolor, Tetragonia expansa andGomphrena globosa reacted with local lesions. Dilution end-point was 10⁴–10⁵, thermal inactivation at c. 60°C and ageing in vitro 4–8 days. With the electron microscope elongate particles with a normal length of about 750 nm could be detected in crude sap. In ultrathin sections virus particles were observed in the cytoplasm, dispersed as well as aggregated. Pinwheel and laminate aggregated inclusions were present in sectioned leaf material. The inclusions observed in negatively stained crude sap preparations exhibited fine linear striations with a periodicity of 5.3 nm.     

Insect epoxide hydrolase: Properties of a purified enzyme from the southern armyworm (Spodoptera eridania)

An epoxide hydrolase purified from midgut microsomes of southern armyworm (Spodoptera eridania) larvae exhibited high activity toward monosubstituted epoxides (1,2-epoxyoctane, 1,2-epoxypropane, and styrene oxide) and lower activity toward cis-1,2-disubstituted epoxides (cyclohexene oxide, and the cyclodienes HEOM, HCE, and chlordene epoxide). Trisubstituted epoxides (2-methyl-2,3-epoxyheptane and JH-1) as well as several cyclodiene insecticides (dieldrin, endrin, endo-epoxyaldrin, and anti-heptachlor epoxide) were refractory to enzymatic attack. It is concluded that both lipophilic and steric factors dictate the substrate specificity of the enzyme. With cyclohexene oxide the enzyme yields the 1R, 2R enantiomer of the trans-diol. The purified enzyme is inhibited by several epoxides and mixed-function oxidase inhibitors and the potency of 3,3,3-trichloro-1,2-epoxypropane and sodium picrylsulfonate suggest the importance of electronic factors in the inhibitory mechanism. Studies with specific amino acid modifiers suggest the presence of an essential lysine or histidine residue at the active site and indicate that the enzyme lacks a metal ion requirement and an essential cysteine residue. The purified enzyme has a molecular weight of 46,000 daltons and amino acid analysis and immunochemical studies show it to be very similar to, but not identical with, the epoxide hydrolase from mammalian liver microsomes.