Data obtained from two experiments were used to identify and describe factors affecting crop loss due to weeds in forage stands. Timothy (Phleum pratense L. ‘Champ′) was established in presence or absence of barley (Hordeum vulgare L. ‘Bruce′), red clover (Trifolium pratense L. ‘Florex′), broadleaf weeds, and grass weeds. Botanical composition, soil water, soil nutrients, light interception, and plant cover were determined 4 and 6 weeks after seeding, and crop yield was determined at periodic forage harvest dates. Principal components analyses permitted the extraction of 12 factors and regression analyses demonstrated that these factors can be used to describe crop yield. Each factor can be estimated either by obtaining the rotated factor scores or by selecting a representative variable that can be substituted for the rotated factor scores in the regression models. The approach described in this paper should be tested with other crops and other weed complexes. It is suggested to use weed density in combination with weed and crop cover data to predict crop loss.

Introduction. Pescabivona is the name of an autochthonous peach [Prunus persica (L.) Batch] population of the central west of Sicily. In a previous work, this fruit was submitted to chemical analysis, while in this paper, sensory evaluation is considered. Materials and methods. Samples of four Pescabivona landraces were harvested throughout the harvest season. A trained panel outlined the sensory profiles and the data were processed by ANOVA and Principal Component Analysis (PCA). A correlation between sensory analysis and instrumental data was finally carried out. Results and discussion. The results demonstrated a high standard of quality for the four landraces studied, with some differences in aroma intensity and in some other parameters, with sweetness and aroma being highly correlated with overall liking. PCA did not clearly separate the different landraces as they have the same origin. Some correlations between sensory analysis and instrumental data were verified. The sensory liking was correlated with the main ripeness parameters, as well as with the pulp firmness. Conclusion. The data obtained contribute to outlining a complete fruit profile for product comparison and shelf-life monitoring. As previously verified for chemical parameters, the sensory evaluation indicates a substantial similarity among the landraces. The good agreement between sensory evaluation and composition makes sensory analysis a precious tool to assess quality of Pescabivona landraces.

Full-field electroretinograms were recorded from five normal human subjects using white light (mean luminance: 250 cd/m2) sine wave stimuli at different frequencies and contrasts. In agreement with previous studies, we found that the amplitude of the fundamental component displayed a dip at about 12 Hz, coinciding with a maximum in the second harmonic component, indicating frequency doubling of the responses. By including measurements at different contrasts, we were able to recognize two (sine-like and transient) response components. We found that the waveform of the transient response was relatively frequency independent. An algorithm to separate the two components was developed. The interaction between these two components can explain the frequency-doubled responses around 12 Hz. The sine-like component is more linear and prominent in the low-frequency region, whereas the transient seems to be more nonlinear and prominent in the high-frequency region.