Estimating butterfly numbers

While various experimental methods may show the number of butterflies in a given area, this, of itself, is no pointer either to general scarcity or to the reverse. Even less can it be taken as being the result of a particular set of outside influences. However, low levels in certain (otherwise plentiful) species may be taken as indicating unsuitable management trends.     

Phase chemistry, structure, and radiation effects in lunar samples

Phase chemistry, structure, and radiation effects were studied in rock, breccia, and soil samples. The regolith apparently developed in the final stages of accretion and was modified by later impact processes and radiation weathering. Exposure ages indicate transfer of buried igneous rock fragments to the near surface late in lunar history. With a few exceptions igneous rock fragments, soil, and breccia share the same distinctive chemistry, probably acquired before accretion of the moon. The igneous rocks texturally resemble basaltic achondrites, and the soil and breccias contain glassy spheres analogous to chondrules.     

Simultaneous identification of soyasaponins and isoflavones and quantification of soyasaponin Bb in soy products,using liquid chromatography/electrospray ionization-mass spectrometry

A method has been developed for simultaneous identification of soyasaponins and soy isoflavones in soy products, based on liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS). Soy-based nutraceutical products were analyzed by LC/ESI-MS with detection of protonated and sodiated molecular ions, as well as characteristic fragment ions for these compounds. Soy isoflavones were characterized by a strong protonated molecular ion in addition to corresponding [aglycone + H](+) ions. Monitoring the soyasaponin-specific protonated aglycone and dehydrated aglycone ions throughout the chromatogram provided a unique fingerprint for soyasaponin content in the samples. This mass spectrometric fingerprint also allowed immediate classification of the soyasaponin analytes as group A or B soyasaponins, based on the unique masses of aglycone ions observed for each class. Quantification of soyasaponin B(b) in soy-derived materials, based on the use of a purified soyasaponin B(b) standard and a glycyrrhizin internal standard, has been accomplished.     

GASTRIC EMPTYING OF SOLID RADIOPAQUE MARKERS IN HEALTHY DOGS

The gastric emptying of 1.5 mm diameter (small) and 5.0 mm diameter (large) radiopaque markers (BIPS) was assessed in 20 dogs. The markers were fed to the dogs in a test meal and abdominal radiographs were made hourly thereafter. Studies were repeated three times in each dog. The variation between two veterinarians interpreting the radiographs was low. The sex, age and day of the study did not have a significant effect on the lag phase or the time taken to empty 25%, 50% and 75% of the markers (T₂₅, T₅₀ and T₇₅ respectively). There was a weak but significant positive correlation between the body weight and T₅₀. There was no significant difference in gastric emptying parameters between the large and small markers.
The mean gastric emptying versus time curve of the small markers on day one was chosen to represent the reference curve for healthy dogs. The lag phase of the small markers on day one was 2.45 ± 2.04 hours, the T₂₅ was 4.85 ± 2.15 hours, the T₅₀ was 6.05 ± 2.99 hours and the T₇₅ was 8.32 ± 2.72 hours (mean ± SD).     

Influence of landscape structure on reef fish assemblages

Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape.

     

Evaluation of a contract breeding management program in selected Ohio dairy herds with event-time analysis I. Cox proportional hazards models

An observational study was conducted in order to assess the impact of a contract breeding program on the reproductive performance in a selected group of Ohio dairies using event-time analysis. The contract breeding program was offered by a breeding co-operative and featured tail chalking and daily evaluation of cows for insemination by co-operative technicians. Dairy employees no longer handled estrus detection activities. Between early 2002 and mid-2004, test-day records related to production and reproduction were obtained for 16,453 lactations representing 11,398 cows in a non-random sample of 31 dairies identified as well-managed client herds of the breeding co-operative. Of the 31 herds, 15 were using the contract breeding at the start of the data acquisition period, having started in the previous 2 years. The remaining 16 herds managed their own breeding program and used the co-operative for semen purchase.

Cox proportional hazards modeling techniques were used to estimate the association of the contract breeding, as well as the effect of other significant predictors, with the hazard of pregnancy. Two separate Cox models were developed and compared: one that only considered fixed covariates and a second that included both fixed and time-varying covariates. Estimates of effects were expressed as the hazard ratio (HR) for pregnancy.

Results of the fixed covariates model indicated that, controlling for breed, herd size, use of ovulation synchronization protocols in the herd, whether somatic cell score exceeded 4.5 prior to pregnancy or censoring, parity, calving season, and maximum test-day milk prior to pregnancy or censoring, the contract breeding program was associated with an increased hazard of pregnancy (HR = 1.315; 95% CI 1.261–1.371). The results of the time-varying covariates model, which controlled for breed, herd size, use of ovulation synchronization protocols, somatic cell score above 4.5, parity, calving season, and testing season also found that the program was associated with an increased hazard of pregnancy (HR = 1.387; 95% CI 1.327–1.451).

The fixed and time-varying covariates models both found similar sets of predictors when analyzing the association of the contract breeding program with hazard of pregnancy. Both models identified a 30% or greater increase in hazard of pregnancy associated with use of the contract breeding program, suggesting that herds subscribing to the program achieved pregnancies in a more timely fashion.