AN IMMUNOFLUORESCENCE DIAGNOSTIC TEST FOR AVIAN INFECTIOUS LARYNGOTRACHEITIS

An antiserum to a recent field isolate of infectious laryngotracheitis virus was conjugated with fluorescein isothiocyanate and used to detect viral antigen to infected chorioallantoic membranes and trachael epithelium by the direct fluorescent antibody technique. In experimentally infected birds, viral antigen was detected with the fluorescent antibody technique from 2 to 14 days post-inoculation but histological evidence of tracheitis was only observed from day three to day ten. The fluorescent antibody test detected 22 of 23 histologically confirmed cases of ILT and was more accurate than virus isolation when used in the diagnosis of respiratory disease from field outbreaks. It was concluded that the speed, accuracy and sensitivity of the fluorescent antibody technique make it a useful tool in the diagnosis of infectious laryngotracheitis.     

Gravity Field over Northern Eurasia and Variations in the Strength of the Upper Mantle

The correlation of long-wavelength gravity anomalies in northern Eurasia with seismic velocity anomalies in the upper mantle reverses in sign between western and eastern Eurasia. The difference between western and eastern Eurasia can be explained by the presence of a low-viscosity zone in the uppermost mantle beneath eastern Eurasia that is absent to the west. The location of the lateral change in viscosity corresponds with the geologic boundary between the older shields and platforms of the Baltics, Russia, and Siberia and the younger, geologically active mountain belts of eastern Asia. This relation provides evidence that differences in the strength of the upper mantle control the locus of intracontinental deformation.     

Web-based technology: its effects on small group "problem-based learning" interactions in a professional veterinary medical program

The objective of this investigation was to ascertain whether and how the introduction of a new technology (WebCT) influenced faculty teaching styles while facilitating small group problem-based learning (PBL) sessions in a professional veterinary medical (PVM) program. The following questions guided the study: (1) How does the use of technology affect faculty teaching behaviors? (2) Do the facilitators' interactions with WebCT technology change over the course of one semester? (3) What is the perceived impact of WebCT on facilitators' role in PBL? The study employed a combination of qualitative (case study) and semi-quantitative (survey) methods to explore these issues. Nine clinical sciences faculty members, leading a total of six PBL groups, were observed over the course of an academic semester for a total of 20 instructional sessions. The qualitative data gathered by observing faculty as they facilitated PBL sessions yielded three major themes: (1) How do PBL facilitators adapt to the addition of WebCT technology? (2) Does this technology affect teaching? and (3) How do PBL facilitators interact with their students and each other over the course of a semester? No direct evidence was found to suggest that use of WebCT affected teaching behaviors (e.g., student-centered vs. teacher-centered instruction). However, all facilitators showed a moderate increase in comfort with the technology during the semester, and one participant showed remarkable gains in technology skills. The teaching theme provided insight into how facilitators foster learning in a PBL setting as compared to a traditional lecture. A high degree of variability in teaching styles was observed, but individuals' styles tended to remain stable over the course of the semester. Nevertheless, all facilitators interacted similarly with students, in a more caring and approachable manner, when compared to the classroom or clinic atmospheres.     

Water and sediment dynamics of penoxsulam and molinate in paddy fields: field and lysimeter studies

BACKGROUND: In Chile, rice is cultivated under water‐seeded and continuously flooded conditions. Because herbicide dynamics in paddy fields and non‐flooded fields is different, 3 year experiments were performed to study the dissipation of molinate and penoxsulam in water and sediment. RESULTS: In field experiments, both herbicides dissipated by 45–55% from the initial applied amounts during the first 6 h after application in all crop seasons; in lysimeter experiments, dissipation amounts were approximately 10% for penoxsulam and 16% for molinate. Penoxsulam field water DT₅₀ values varied from 1.28 to 1.96 days during the three study seasons, and DT₉₀ values from 4.07 to 6.22 days. Molinate field water DT₅₀ values varied from 0.89 to 1.73 days, and DT₉₀ values from 2.82 to 5.48 days. Sediment residues were determined 2 days after herbicide application into the paddy water, and maximum concentrations were found 4–8 days after application. In sediment, DT₅₀ values varied from 20.20 to 27.66 days for penoxsulam and from 15.02 to 29.83 days for molinate. CONCLUSIONS: Results showed that penoxsulam and molinate losses under paddy conditions are dissipated rapidly from the water and then dissipate slowly from the sediment. Penoxsulam and molinate field water dissipation was facilitated by paddy water motion created by the wind. Sediment adsorption and degradation are considered to have a secondary effect on the dissipation of both herbicides in paddy fields. Copyright © 2011 Society of Chemical Industry     

Simazine dynamics in a vineyard soil at Casablanca valley, Chile

Field dissipation, soil movement and laboratory leaching studies were performed to elucidate the effect of two rainfall amounts in the behaviour and environmental fate of simazine under climatic conditions at Casablanca Valley, Chile. Dissipation and soil movement were studied in a field vineyard with a sandy loam soil (Inceptisol; 74.08% sand; 14.87% silt and 11.04% clay). Simazine was applied to bare soil at 2.0 kg AI ha(-1), and its concentration was measured using immunoassay (ELISA) at 0, 10, 20, 40 and 90 days after application under two rainfall amounts, natural field conditions (39 mm) and modified conditions (39 + 180 mm). Simazine leaching was studied using soil core PVC lysimeters (0.9 m height; 0.22 m diameter). Field dissipation data were adjusted with a bi-exponential model. Half-life (DT(50)) values varied between 31.3 (+/-2.5) and 19.0 (+/-4.2) days under natural and modified conditions, respectively. Simazine K(d) varied from 0.42 to 2.15 (K(oc) 32.6-216.2) in the soil profile. Simazine was detected at a 90-cm soil depth in concentrations of 0.0085 (+/-0.0043) mg kg(-1) and 0.0321 (+/-0.001) mg kg(-1) under field and modified conditions, respectively. The maximum simazine leachate concentrations were 0.013 (+/-0.00084) mg litre(-1) (0.012% of total applied simazine) and 0.0084 (+/-0.00082) mg litre(-1) (0.11% of total applied simazine) for field and modified conditions respectively. These data indicate that water quantity has a significant effect on the DT(50) and the amount of simazine that moved through the soil profile, but not on the soil depth reached by this herbicide.     

Determination of Venus Winds by Ground-Based Radio Tracking of the VEGA Balloons

A global array of 20 radio observatories was used to measure the three-dimensional position and velocity of the two meteorological balloons that were injected into the equatorial region of the Venus atmosphere near Venus midnight by the VEGA spacecraft on 11 and 15 June 1985. Initial analysis of only radial velocities indicates that each balloon was blown westward about 11,500 kilometers (8,000 kilometers on the night side) by zonal winds with a mean speed of about 70 meters per second. Excursions of the data from a model of constant zonal velocity were generally less than 3 meters per second; however, a much larger variation was evident near the end of the flight of the second balloon. Consistent systematic trends in the residuals for both balloons indicate the possibility of a solar-fixed atmospheric feature. Rapid variations in balloon velocity were often detected within a single transmission (330 seconds); however, they may represent not only atmospheric motions but also self-induced aerodynamic motions of the balloon.