7,496 research outputs found
Expressing the tacit knowledge of a digital library system as linked data
Library organizations have enthusiastically undertaken semantic web initiatives and in particular the data publishing as linked data. Nevertheless, different surveys report the experimental nature of initiatives and the consumer difficulty in re-using data. These barriers are a hindrance for using linked datasets, as an infrastructure that enhances the library and related information services. This paper presents an approach for encoding, as a Linked Vocabulary, the "tacit" knowledge of the information system that manages the data source. The objective is the improvement of the interpretation process of the linked data meaning of published datasets. We analyzed a digital library system, as a case study, for prototyping the "semantic data management" method, where data and its knowledge are natively managed, taking into account the linked data pillars. The ultimate objective of the semantic data management is to curate the correct consumers' interpretation of data, and to facilitate the proper re-use. The prototype defines the ontological entities representing the knowledge, of the digital library system, that is not stored in the data source, nor in the existing ontologies related to the system's semantics. Thus we present the local ontology and its matching with existing ontologies, Preservation Metadata Implementation Strategies (PREMIS) and Metadata Objects Description Schema (MODS), and we discuss linked data triples prototyped from the legacy relational database, by using the local ontology. We show how the semantic data management, can deal with the inconsistency of system data, and we conclude that a specific change in the system developer mindset, it is necessary for extracting and "codifying" the tacit knowledge, which is necessary to improve the data interpretation process
Eligible strategies of drought response to improve drought resistance in woody crops: a mini-review
Drought is the main abiotic stress that negatively affects the crop yield. Due to the rapid climate change, actual plant defence mechanisms may be less effective against increased drought stress and other related or co-occurring abiotic stresses such as salt and high temperature. Thus, genetic engineering approaches may be an important tool for improving drought tolerance in crops. This mini-review focuses on the responses to drought stress of the woody crop species Olea europaea and Citrus sp., selecting in particular five main strategies adopted by plants in response to drought stress: aquaporin (AQPs) expression, antioxidant activity, ABA signalling, and trehalose and proline accumulation. Transgenic studies on both the herbaceous Arabidopsis and woody Populus plant models showed an improvement in drought resistance with increasing expression of these drought-inducible genes. Outcomes from the present study suggest the overexpression of the gene families associated with AQPs and ABA biosynthesis, mainly involved in regulating water transport and in preventing water loss, respectively, as candidate targets for improving drought resistance; antioxidants-, trehalose- and proline-related genes remain valid candidates for resistance to a wider spectrum of abiotic stressors, including drought. However, the contribution of an increased stiffness of the modulus elasticity of leaf parenchyma cell walls to the rapid recovery of leaf water potential, delaying by this way the stress onset, is not a secondary aspect of the transgenic optimization, in particular for Olea cultivars
Root seasonal pattern, spatial distribution, and C:N ratio of matgrasspasture (Nardus stricta L.) in the Lombardy Prealps
The aim of the present study was to investigate carbon and nutrient cycling and the role of root dynamics in terrestrial
ecosystems such as large abandoned pastures and natural grasslands present in the Prealps, for which below-ground
processes are currently enigmatic. In particular, we quantified root/leaf biomass and C:N ratio throughout two growing
seasons. Additionally, root traits such as root length density (RLD), root mass density (RMD), and root diameter classes
(RDC) were also investigated with the aim of understanding the spatial distribution of roots in the soil. In our samples, we
found that the roots could be divided into three main diameter classes and hence quantified the presence of each class along
the soil profile. With regard to total root biomass, we found the occurrence of two peaks of biomass accumulation during
the growth season, and when biomass accumulation was compared with climatic data, it was impossible to obtain a clear
indication of the root turnover rate. In fact, the strong influence of grazing on the above-ground biomass could have
affected, in turn, root biomass. In future, this possible complication will be avoided by repeating the measurements within
enclosures to avoid grazing interference. We found that C:N ratio remained constant, with a single peak, suggesting a lower
root decomposition during the warmest period (August 2006). The concentration of nitrogen in roots decreased with depth
as a result of a decrease in roots with smaller diameters. The reverse was found for carbon content, which increased with
depth, probably due to an increase in roots with larger diameters. This study represents the first attempt to estimate root
turnover rates in this prealpine ecosystem, which have been analysed to date only for the above-ground biomass
Fine-root carbon and nitrogen concentration of European beech (Fagus sylvatica L.) in Italy Prealps: possible implications of coppice conversion to high forest
Fine-root systems represent a very sensitive plant compartment to environmental changes. Gaining further knowledge about their dynamics would improve soil carbon input understanding. This paper investigates C and N concentrations in fine roots in relation to different stand characteristics resulting from conversion of coppiced forests to high forests. In order to evaluate possible interferences due to different vegetative stages of vegetation, fine-root sampling was repeated six times in each stand during the same 2008 growing season. Fine-root sampling was conducted within three different soil depths (0-10; 10-20; and 20-30 cm). Fine-root traits were measured by means of WinRHIZO software which enable us to separate them into three different diameter classes (0-0.5, 0.5-1.0 and 1.0-2.0 mm). The data collected indicate that N concentration was higher in converted stands than in the coppiced stand whereas C concentration was higher in the coppiced stand than in converted stands. Consequently the fine-root C:N ratio was significantly higher in coppiced than in converted stands and showed an inverse relationship with fine-root turnover rate, confirming a significant change of fine-root status after the conversion of a coppice to high forest
Oral health of elite athletes and association with performance: a systematic review.
We aimed to systematically review the epidemiology of oral disease and trauma in the elite athlete population and to investigate the impact of oral health on sporting performance
Effect of tree density on root distribution in Fagus sylvatica stands: a semi-automatic digitising device approach to trench wall method
5Knowledge of root profiles is essential for
measuring and predicting ecosystem dynamics and function.
In the present study, the effects of management
practices on root (0.5 <= ø < 20 mm) spatial distribution
were examined in a 40-year-old coppice stand (CpS 1968)
and other two stands converted from coppice to thinned
high forest in 1994 (CvS 1994) and 2004 (CvS 2004),
respectively. The use of a semi-automatic digitising device
approach was compared with a conventional root mapping
method in order to estimate the time per person required
from fieldwork to the final digital map. In July 2009, six
trench walls per stand were established according to tree
density, i.e. as equidistant as possible from all surrounding
trees. Findings highlighted differences between the stands
with CvS 1994 showing a lower number of small roots
(2 <= ø < 5 mm), a higher mean cross-sectional area
(CSA) of coarse roots (5 <= ø < 20 mm) and different root
depth distribution as compared to CpS 1968 and CvS 2004
whose values were close to each other. The three diameter
classes selected in this study showed significant relationships
in terms of number of roots, scaling down from
coarse- to small- and fine-roots. Forest management
practices significantly affected only the number of small
roots. The number of fine roots (0.5 <= ø < 2 mm) was isometrically related to their root length density (RLD,
cm cm-3). No relationship occurred with RLD of very fine
roots (ø < 0.5 mm). In conclusion, forest management
practices in terms of conversion thinnings significantly
affected belowground biomass distribution of beech forest
in space and time. In particular, frequency of coarse roots
was related to the stand tree density, frequency of small
roots was related to the cutting age. Size of coarse roots
was related to tree density but only several years after
felling. The allometric relationship occurring between fineand
small-roots highlighted how fine root number and RLD
were only indirectly affected by forest management practices.
These findings suggest that future investigations on
the effect of forest thinning practices on fine-root traits like
number, length and biomass several years after felling
cannot ignore those on small roots.openDi Iorio, A.; Montagnoli, A.; Terzaghi, M.; Scippa, G.S.; Chiatante, D.DI IORIO, Antonino; Montagnoli, A.; Terzaghi, M.; Scippa, G. S.; Chiatante, Donat
Fine-root seasonal pattern, production and turnover rate of European beech (Fagus sylvatica L.) stands in Italy Prealps: Possible implications of coppice conversion to high forest
The aim of this study was to investigate the possible effects of coppice conversion to high forest on the beech fine-root
systems. We compared the seasonal pattern of live and dead fine-root mass (d<2 mm), production and turnover in three
beech stands that differed in management practices. Tree density was higher in the 40-year-old coppice stand than in the
stands that were converted from coppice to high forest in 1994 and 2004, respectively. We found that a reduction in tree
density reduced the total fine-root biomass (Coppice stand, 353.8 g m-2; Conversion 1994 stand, 203.6 g m-2;
Conversion 2004 stand, 176.2 g m-2) which continued to be characterised by a bimodal pattern with two major peaks,
one in spring and one in early fall. Conversion to high forest may also affect the fine-root soil depth distribution. Both
fine-root production and turnover rate were sensitive to management practices. They were lower in the Coppice stand
(production 131.5 g m-2 year-1; turnover rate 0.41 year-1) than in the converted stands (1994 Conversion stand:
production 232 g m-2 year-1, turnover rate 1.06 year-1; 2004 Conversion stand: production 164.2 g m-2 year-1,
turnover rate 0.79 year-1)
Influence of soil temperature and water content on fine-root seasonal growth of European beech natural forest in Southern Alps, Italy
In tree species, fine-root growth is influenced by the interaction between environmental factors such as soil temperature (ST) and soil moisture. Evidences suggest that if soil moisture and nutrient availability are adequate, rates of root growth increase with increasing soil temperature up to an optimum and then decline at supraoptimal temperatures. These optimal conditions vary between different taxa, the native environment and the fine-root diameter sub-classes considered. We investigated the effects of seasonal changes of both ST and soil water content (SWC) on very fine (d < 0.5 mm) and fine-root (0.5 < d < 2 mm) mass (vFRM, FRM) and length (vFRL, FRL) in Italian Southern Alps beech forests (Fagus sylvatica L.). Root samples were collected by soil core method. Turnover rate was higher for the very fine (0.51) than for the fine (0.36) roots. vFRM, FRM, vFRL and FRL displayed a complex seasonal pattern peaking in summer when SWC was around 40 % and ST was around 14 \ub0C. Above this temperature, under almost constant SWC, all above mentioned root traits decreased. vFRM, FRM, vFRL and FRL showed significant second-order polynomial relationship (p < 0.05) with SWC for both diameter classes, with the only exception of SRL. ST showed the same kind of relationship significant only with vFRM and vFRL, the latter within the 12-16 \ub0C smaller range. Interpolation analysis between root mass and length for both diameter classes and investigated soil environmental characteristics (ST and SWC) showed a clear roundish delineation only for vFRM. In conclusion, these findings clarified the occurrence of a bimodal fine-root growth seasonal pattern for our beech forest. The optimal growth ST and SWC ranges were delineated only for very fine roots, giving further evidence on this root category as the more responsiveness to soil environmental changes. Furthermore, F. sylvatica seems to adopt an intensive strategy to cope with decreasing SWC. Finally, fine-root growth, mainly radial type, seems to be driven by SWC, whereas very fine-root growth, mainly longitudinal type, seems to be driven by ST
Strategies to improve the postharvest management of flat oyster (Ostrea edulis) from aquaculture using the short-term storage and package in an innovative closed-circuit system
This study aimed to improve postharvest management of flat oysters reared in a longline system in the mid Adriatic Sea, using short-term storage and package in an innovative closed-circuit system. For the trial, 870 oysters were employed, divided into three experimental groups (A, B, and C), N = 270 oysters each group, whereas the remaining 60 oysters were used for the 2 controls. Each group differed in relation to the time spent in the depuration tank and the time of packaging: group A was packed and immediately transferred to the cell; group B was depurated in a tank for 48 h, then packed and transferred to the cell; group C was depurated in a tank for 48 h and then packed, depurated for another 24 h and transferred to a cell. Samples of each group were sampled at different times of permanence in cell (t0) up until 12 days (t12) for biomorphometric, sensorial, nutritional, and microbiological analysis. Although the nutritional and sensorial quality of the oysters was more pronounced in group A, B and C groups also showed good results. In these two groups, thanks to the use of the modern water recirculation system the quality and safety of oysters was improved by reducing the presence of sludge and eliminating fecal contaminants completely than A treatment and seawater control. These results were also confirmed by the tank control, where a more extended depuration period positively influenced the same parameters emphasizing the importance of the adequate depuration processes in oyster productio
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