1,721,441 research outputs found
Planting models for new olive growing
No full textThe European or Mediterranean cultivated olive (Olea europaea L., subsp. europaea, var. europaea) is an ancient crop notable for its early domestication. Today, hundreds of olive varieties are grown to produce high-quality fruit for oil and table olives for human consumption. Over the last 30 years, the olive industry has undergone profound innovation due to scientific and technical advances, particularly in genomics, breeding, orchard management, mechanization and agro-ecology. Not all these developments are currently available to smaller producers.
Outside the Mediterranean Basin, where it has been present for over 6,000 years, olive cultivation has spread to many other countries. These new olive-growing areas are helping further the expansion of the industry, due to increased awareness of the nutritional and health properties of extra virgin olive oil
Micro-arthropod communities under human disturbance: is taxonomic aggregation a valuable tool for detecting multivariate change? Evidence from Mediterranean soil oribatid coenoses
No full textAnimal communities are sensitive to environmental disturbance, and several multivariate methods have recently been developed to detect changes in community structure. The complex taxonomy of soil invertebrates constrains the use of the community level in monitoring environmental changes, since species identification requires expertise and time. However, recent literature data on marine communities indicate that little multivariate information is lost in the taxonomic aggregation of species data to high rank taxa. In the present paper, this hypothesis was tested on two oribatid mite (Oribatida, Acari) assemblages under two different kinds of disturbance: metal pollution and fires. Results indicate that data sets built at the genus and family systematic rank can detect the effects of disturbance with little loss of information. This is an encouraging result in view of the use of the community level as a preliminary tool for describing patterns of human-disturbed soil ecosystems
Determinants of Antarctic epilithic lichen distribution in northern Victoria Land (Antarctica)
No full textModelling the local probability of occurrence of the prostigmatic mite Streotydeus belli in Antarctic ice-free areas
No full textA new formulation of the geometric series with applications to oribatid (Acari, Oribatida) species assemblages from human-disturbed Mediterranean areas
No full textThe mathematical properties of the geometric series are revisited and the model is applied to oribatid mite (Acari, Oribatida) assemblages from Mediterranean areas that have been disturbed by human activity. In the past, the geometric series has been considered an ideal form of Fisher’s log model. However, in some cases data fit both models or the geometric series offers a better fit. Data presented in this paper and collected from areas heavily disturbed by human activity show that the species abundance distribution of oribatids is in almost all cases well fitted by the geometric series, indicating a common trend in the response to disturbance of this assemblage. The proposed new version of the model allows interesting applications in environmental monitoring because it is easy to outline the quantitative relationship between the abundance of the most abundant species, the total number of individuals and the total number of species in the sample
Propagation techniques and nursery management for the production of certified peach plants in Europe
No full textThe propagation of fruit trees, particularly peaches, nectarines and canning
clingstone, has reached highly specialized levels since the 1960s. Over the years, the
classic seed rootstocks have been replaced by numerous rootstocks produced in vitro,
expanding the range of technical solutions for the different soil and climatic growing
conditions of several areas. Thanks to the new genotypes from international breeding
programs, it was thus possible to renew the cultivated varietal platform several times.
Propagation techniques have also undergone an evolution, adopting solutions aimed at
shortening nurseries’ production cycles by using June budding or micrografting.
Finally, there are different types of plants available for peach growers. Bare root plants,
potted trees of different sizes with several mixture also activated by bio agents are
suitable for the different growing and training systems to be adopted. In order to
guarantee trueness to type and plant health and to counteract the introduction and
spread of dangerous harmful organisms in Europe, at EU level, production and
marketing of plant propagation materials is also regulated by mandatory standards for
peach trees, although it is possible to join to voluntary certification schemes which
ensure higher guarantee to the plants. All these issues are being discussed in the
current article
Identifying appropriate sampling and modelling approaches for analysing distributional patterns of Antarctic terrestrial arthropods along the Victoria Land latitudinal gradient
Get PDFBiotic communities in Antarctic terrestrial ecosystems are relatively simple and often lack higher trophic levels (e. g. predators); thus, it is often assumed that species' distributions are mainly affected by abiotic factors such as climatic conditions, which change with increasing latitude, altitude and/or distance from the coast. However, it is becoming increasingly apparent that factors other than geographical gradients affect the distribution of organisms with low dispersal capability such as the terrestrial arthropods. In Victoria Land (East Antarctica) the distribution of springtail (Collembola) and mite (Acari) species vary at scales that range from a few square centimetres to regional and continental. Different species show different scales of variation that relate to factors such as local geological and glaciological history, and biotic interactions, but only weakly with latitudinal/altitudinal gradients. Here, we review the relevant literature and outline more appropriate sampling designs as well as suitable modelling techniques (e. g. linear mixed models and eigenvector mapping), that will more adequately address and identify the range of factors responsible for the distribution of terrestrial arthropods in Antarctica.</p
The size and shape of shells used by hermit crabs: A multivariate analysis of Clibanarius erythropus
No full textShell attributes Such as weight and shape affect the reproduction, growth, predator avoidance and behaviour of several hermit crab species. Although the importance of these attributes has been extensively investigated, it is still difficult to assess the relative role of size and shape. Multivariate techniques allow concise and efficient quantitative analysis of these multidimensional properties, and this paper aims to understand their role in determining patterns of hermit crab shell use. To this end, a multivariate approach based on a combination of size-unconstrained (shape) PCA and RDA ordination was used to model the biometrics of southern Mediterranean Clibanarius erythropus Populations and their shells. Patterns of shell utilization and morphological gradients demonstrate that size is more important than shape, probably due to the limited availability of empty shells in the environment. The shape (e.g. the degree of shell elongation) and weight of inhabited shells vary considerably in both female and male crabs. However, these variations are clearly accounted for by crab biometrics in males only. Oil the basis of statistical evidence and findings from past studies. it is hypothesized that larger males of adequate size and strength have access to the larger, heavier and relatively more available shells of the globose Osilinus turbinatus, which cannot be used by average-sized males or by females investing energy in egg production. This greater availability allows larger males to select more Suitable Shapes. (C) 2009 Elsevier Masson SAS. All rights reserved.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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