130,481 research outputs found
Intercepted photosynthetically active radiation (Par) and spatial and temporal distribution of transmitted par under high-density and super high-density olive orchards
No full textWe quantified the photosynthetically active radiation (PAR) interception in a high-density (HD) and a super high-density (SHD) or hedgerow olive system, by measuring the PAR transmitted under the canopy along transects at increasing distance from the tree rows. Transmitted PAR was measured every minute, then cumulated over the day and the season. The frequencies of the different PAR levels occurring during the day were calculated. SHD intercepted significantly but slightly less overall PAR than HD (0.57 ± 0.002 vs. 0.62 ± 0.03 of the PAR incident above the canopy) but had a much greater spatial variability of transmitted PAR (0.21 under the tree row, up to 0.59 in the alley center), compared to HD (range: 0.34-0.43). This corresponded to greater variability in the frequencies of daily PAR values, with the more shaded positions receiving greater frequencies of low PAR values. The much lower PAR level under the tree row in SHD, compared to any position in HD, implies greater self-shading in lower-canopy layers, despite similar overall interception. Therefore, knowing overall PAR interception does not allow an understanding of differences in PAR distribution on the ground and within the canopy and their possible effects on canopy radiation use efficiency (RUE) and performance, between different architectural systems
Maturazione ed epoca di raccolta delle olive
No full textVengono illustrati i principali fattori fisiologici e tecnici che influiscono sulla raccolta
Evaluation of different mechanical fruit harvesting systems and oil quality in very large size olive trees
No full textIn 2006 and 2009, trials were carried out in the Apulia region in Southern Italy to evaluate the possibility of mechanizing olive harvesting in groves of old and very large trees. The trees belonged to the cultivars ‘Cellina di Nardò’ and ‘Ogliarola Salentina’. They were 60-100 years old and 7-9 m tall with a canopy volume of 140-360 m3. In the first half of November 2006, with a mechanical beater mounted on a tractor plus hand-held pneumatic combs, the harvesting yield was close to 90% of the total olives present in the canopy, and the harvesting working productivity was around 60 kg of harvested olives h–1 worker–1. With a self-propelled shaker attached to the main branches the harvesting yield was about 73% in ‘Cellina di Nardò’, and 40% in ‘Ogliarola Salentina’, while the harvesting working productivities were around 103 and 85 kg of harvested olives h–1worker–1, respectively. In the second half of November 2009, in ‘Cellina di Nardò’, with a mechanical beater mounted on a tractor plus nets on the ground or a catching frame (reversed umbrella) mounted on another tractor, the harvesting yield was about 97%. The working productivity was about 98 kg of harvested olives h–1 worker–1 with the mechanical beater plus nets and around 133 kg of harvested olives h–1 worker–1 when the mechanical beater was combined with a reversed umbrella. The oil obtained from the mechanically harvested olives was always of high quality. A basic economic evaluation of the harvesting costs is also reported
Raccolta agevolata e meccanizzata
No full textVengono passati in rassegna i correnti metodi e tecnologia per la raccolta delle olive. La raccolta agevolata avviene con attrezzi di costo contenuto utilizzati direttamente dall'operatore, mentre la raccolta meccanica richieda l'impiego di macchinari anche molto costosi. dal punto di vista dell'efficienza e dell'economia di gestione della raccolta, l'organizzazione del cantiere è estrememente importante. Ve ngono illustrate le principali macchine disponibili per l araccolta delle olive
Gestione della chioma
No full textBayer CrpScience - Collana Coltura & Cultura. Coordinamento generale Renzo Angelini. Coordinamento scientifico Michele Pisante, Paolo Inglese, Giovanni Lercke
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Time and type of pruning affect tree growth and yield in high-density olive orchards
No full textThe effect of different strategies and the time of pruning on olive vegetative-reproductive behavior was studied in a 5-year-old high-density orchard (1,250 trees ha− 1, cv. ‘Ascolana tenera’). The treatments were: a) winter lateral pruning and topping, b) summer lateral pruning and winter topping, c) winter lateral pruning and summer topping and d) summer lateral pruning and topping. Selective spring pruning maintaining a conical shape of the canopy was used as the Control. Topping significantly maintained tree height recorded at the end of the 3-year trial in comparison to the Control (3.84 ± 0.45 m), in particular summer treatments maintained the final tree height at 3.0 ± 0.26 m. Summer topping and lateral pruning significantly reduced canopy volume compared to winter pruning and the Control. There was less vegetative re-sprouting in the control and, on the average, less for summer than for winter pruning in the same year of pruning. There were no significant differences between the treatments regarding the seasonal vegetative growth of 1-year-old mixed shoots. Fruit yield per tree was significantly higher with time-split pruning (part in winter and part in summer) with respect to conical-shape pruning of the canopy. Results suggest that the proposed management of pruning with winter lateral pruning and summer topping contributes to good vegetative-reproductive balance of young trees with high yield and a more compact shape
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Effects of summer pruning on the water status and physiology of olive trees and on fruit characteristics and oil quality
No full textAn investigation was carried out in 2017 in central Italy, in an adult olive orchard with trees of the cultivar Leccino, spaced 5 x 5 m, trained to a vase and pruned biennially. The aim was to evaluate the effects of summer pruning (i.e. eliminating suckers, in the central part of the canopy, in the non-pruning year), on the water status and physiology of the leaves, on the yield/tree, and on fruit characteristics and oil quality. Unpruned trees were used as the control. During the investigation (July-October), rainfall was low (less than 100 mm) and the orchard was not irrigated. During the summer, the leaves of summer-pruned trees had higher relative water content (RWC) and greater photosynthetic activity than those of control trees. Summer-pruned trees had similar yield, but higher oil content on a dry-weight basis. Oil qualitative parameters (free acidity, peroxide value and spec-trophotometric absorbances in the ultra-violet) were similar, whereas the total content of phenolic compounds was higher in control trees. The oils from summer-pruned trees were more herbaceous and fruity, and less bitter and spicy than oils from control trees. The results show that in situations where there is considerable formation of suckers, such as in the case of biennial, triennial or plurennial pruning, summer pruning can contribute to improving tree water status and the physiological condition, favoring photosynthetic activity. This practice also has effects on fruit oil content and oil quality, producing more aromatic and less bitter and spicy oil. Overall, the results indicate that summer pruning can have effects similar to irrigation
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