Search results for "Tree"
showing 10 items of 1841 documents
Recurrent deficit irrigation and fruit harvest affect tree water relations and fruitlet growth in ‘valencia’ orange
2019
Background – Partial rootzone drying is an irrigation strategy known for increasing water use efficiency without significantly affecting tree water status. ‘Valencia’ oranges have a very long development period and nearly mature fruit and new fruitlets may be present at the same time on the tree, competing for water and assimilates. Objectives – The present study investigates the effect of recurrent deficit irrigation and fruit harvest on tree water status and fruitlet growth of ‘Valencia’ orange. Methods – Forty-eight adult trees were exposed to three irrigation treatments for seven years (2007–2013): irrigation with 100% of ETc (CI), continuous deficit irrigation (DI, 50% of CI) and parti…
Incidence and epidemiology of Citrus tristeza virus in the Valencian Community of Spain
2000
Abstract The first outbreak of citrus tristeza disease in Spain caused by Citrus tristeza virus (CTV) was recorded in 1957 in the Valencian Community (VC). In total c. 40 million trees, mainly of sweet orange and mandarin grafted on sour orange rootstocks, declined due to CTV. Large-scale surveys in different municipalities of the VC indicated that the disease spread very fast. Incidence increased from 11% in 1989 to 53% in 1998. Toxoptera aurantii and Aphis spiraecola (inefficient aphid vectors of CTV) predominated before 1985–87. Since then the relatively efficient vector Aphis gossypii has become dominant and induced an epidemic that has been modelled. The large number of A.gossypii that…
Wellfounded Trees and Dependent Polynomial Functors
2004
We set out to study the consequences of the assumption of types of wellfounded trees in dependent type theories. We do so by in- vestigating the categorical notion of wellfounded tree introduced in [16]. Our main result shows that wellfounded trees allow us to define initial algebras for a wide class of endofunctors on locally cartesian closed cat- egories.
Recursive partitioning: an approach based on the weighted kemeny distance
2015
In the framework of preference rankings, the interest can lie in finding which predictors and which interactions are able to explain the observed preference structures. The possibility to derive consensus measures using a classification tree represents a novelty and an important tool, given its easy interpretability. This work proposes the use of a univariate decision tree for ranking data based on the weighted Kemeny distance. The performance of the methodology will be shown by using a real dataset about university rankings.
Positive selection in development and growth rate regulation genes involved in species divergence of the genus Radix
2015
AbstractBackgroundLife history traits like developmental time, age and size at maturity are directly related to fitness in all organisms and play a major role in adaptive evolution and speciation processes. Comparative genomic or transcriptomic approaches to identify positively selected genes involved in species divergence can help to generate hypotheses on the driving forces behind speciation. Here we use a bottom-up approach to investigate this hypothesis by comparative analysis of orthologous transcripts of four closely related EuropeanRadixspecies.ResultsSnails of the genusRadixoccupy species specific distribution ranges with distinct climatic niches, indicating a potential for natural …
Evolutionary analysis of G-proteins in early metazoans: Cloning of α- and β-subunits from the sponge Geodia cydonium1The sequences reported here have…
1998
G-protein-coupled (seven-transmembrane segment)-receptors represent a major group of metazoan receptors, involved in transduction of extracellular signals. The G-proteins, which are made up of Galpha/beta/gamma-subunits, link the receptors to the effector system(s). To analyze the phylogenetic relationships among the metazoan alpha-subunits of G-proteins, cDNAs of alpha-subunits were isolated from Geodia cydonium, a marine sponge belonging to the lowest metazoan phylum, Porifera. One encodes a putative isotype of a stimulator of the adenylyl cyclase (Galpha s), another one a putative inhibitor of the adenylyl cyclase (Galpha i/o) and the third one a putative activator of phospholipase C (Ga…
Cloning of sponge heat shock proteins: evolutionary relationships between the major kingdoms
2009
In the present study we have cloned from sponges (Porifera) those molecules which are involved in the protection of organisms against physiological and stress conditions; the inducible heat shock protein Mr 70,000, hsp70, from the marine sponge Geodia cydonium, its interacting hsp40, a DnaJ-like protein (from G. cydonium) and the constitutively expressed counterpart the glucose-regulated protein Mr 78,000, GRP78 from Suberites domuncula. Alignments of the sequences revealed that the deduced aa sequences of all sponge hsp's share high homology to other metazoan sequences, and are separated from related sequences from plants and fungi (hsp70, GRP78, DnaJ) as well as Bacteria (DnaK, the hsp70 …
Receptor Tyrosine Kinase, an Autapomorphic Character of Metazoa: Identification in Marine Sponges
1999
In the present review we summarize sequence data obtained from cloning of sponge receptor tyrosine kinases [RTK]. The cDNA sequences were mainly obtained from the marine sponge Geodia cydonium. RTKs (i) with immunoglobulin [Ig]-like domains in the extracellular region, (ii) of the type of insulinlike receptors, as well as (iii) RTKs with one extracellular speract domain, have been identified. The analyses revealed that the RTK genes are constructed in blocks [domains], suggesting a blockwise evolution. The phylogenetic relationships of the sequences obtained revealed that all sponge sequences fall into one branch of the evolutionary tree, while related sequences from higher Metazoa, human, …
A local complexity based combination method for decision forests trained with high-dimensional data
2012
Accurate machine learning with high-dimensional data is affected by phenomena known as the “curse” of dimensionality. One of the main strategies explored in the last decade to deal with this problem is the use of multi-classifier systems. Several of such approaches are inspired by the Random Subspace Method for the construction of decision forests. Furthermore, other studies rely on estimations of the individual classifiers' competence, to enhance the combination in the multi-classifier and improve the accuracy. We propose a competence estimate which is based on local complexity measurements, to perform a weighted average combination of the decision forest. Experimental results show how thi…
A reappraisal of the Pleurotus eryngii complex – New species and taxonomic combinations based on the application of a polyphasic approach, and an ide…
2014
The Pleurotus eryngii species-complex comprises choice edible mushrooms growing on roots and lower stem residues of Apiaceae (umbellifers) plants. Material deriving from extensive sampling was studied by mating compatibility, morphological and ecological criteria, and through analysis of ITS1-5.8S-ITS2 and IGS1 rRNA sequences. Results revealed that P. eryngii sensu stricto forms a diverse and widely distributed aggregate composed of varieties elaeoselini, eryngii, ferulae, thapsiae, and tingitanus. Pleurotus eryngii subsp. tuoliensis comb. nov. is a phylogenetically sister group to the former growing only on various Ferula species in Asia. The existence of Pleurotus nebrodensis outside of S…