229 research outputs found

    Humus forms as a synthetic parameter for ecological investigations. Some examples in the Ligurian Alps (North-Western Italy)

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    In the Ligurian Alps, a wide range of site conditions that influence soil development and may affect humus variability is present. In this work, we wanted to evaluate the potentialities of humus forms as a synthetic indicator of both chemical properties of the humic episola and site conditions in the upper Tanaro Valley (NW Italy). Vegetation affected the C/N ratio of the least transformed organic horizons, but the effect disappeared in mineral ones, where soil pH was related to the parent material. All terrestrial humus forms were found in the area and their distribution well reflected the interactions between vegetation, lithology, elevation that shaped soil properties and affected the degradability of litter and its actual degradation by microorganisms and soil fauna. Humus forms were thus able to capture the ecological conditions, integrating the information provided by soil classifications

    Sequence-independent identification of active LTR retrotransposons in Arabidopsis

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    Detection of retrotransposons capable of contemporary transposition is hampered by the replicative nature of their movement and is usually limited to fortuitous observations of new integration events causing visible phenotypes. To circumvent this shortcoming, we developed a screening strategy for novel active retrotransposons containing long terminal repeats (LTR-TEs). Our approach is based on specific recovery of an LTR region that is part of the linear extrachromosomal DNA (ecDNA) synthetized in the reverse transcription step of the LTR-TE replication/transposition cycle. The method is inexpensive and straightforward and does not require prior knowledge of the retroelement sequence. Here we demonstrate the high sensitivity and specificity of this approach using Arabidopsis mutants with known retrotransposon activities. Using this method, we then identified a novel and mobile retroelement in the Landsberg erecta Arabidopsis ecotype that is absent in the annotated reference genome of Col-0. The cost-effective procedure presented here can be used to identify transposition-competent LTR-retrotransposons in a broad variety of biological specimens, independent of their sequence annotation.This work was supported by European Research Council (EVOBREED) [322621]; and Gatsby Fellowship [AT3273/GLE]

    One-Parameter Homothetic Motion in the Hyperbolic Plane and Euler-Savary Formula

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    In \cite{Mul} one-parameter planar motion was first introduced and the relations between absolute, relative, sliding velocities (and accelerations) in the Euclidean plane E2\mathbb{E}^2 were obtained. Moreover, the relations between the Complex velocities one-parameter motion in the Complex plane were provided by \cite{Mul}. One-parameter planar homothetic motion was defined in the Complex plane, \cite{Kur}. In this paper, analogous to homothetic motion in the Complex plane given by \cite{Kur}, one-parameter planar homothetic motion is defined in the Hyperbolic plane. Some characteristic properties about the velocity vectors, the acceleration vectors and the pole curves are given. Moreover, in the case of homothetic scale hh identically equal to 1, the results given in \cite{Yuc} are obtained as a special case. In addition, three hyperbolic planes, of which two are moving and the other one is fixed, are taken into consideration and a canonical relative system for one-parameter planar hyperbolic homothetic motion is defined. Euler-Savary formula, which gives the relationship between the curvatures of trajectory curves, is obtained with the help of this relative system

    Editorial: Interactions of Plants With Bacteria and Fungi: Molecular and Epigenetic Plasticity of the Host

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    Editorial on the Research Topic 'Interactions of Plants with Bacteria and Fungi: Molecular and Epigenetic Plasticity of the Host

    Donar, un cambio de vida: comprender la experiencia de familiares que aceptaron la donación de órganos

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    Indexación: Web of Science; Scielo.Background: Most organ donors are already death. Therefore family members become an essential link in the final decision for organ donation. Aim: To get acquainted about the life lessons of people who accepted donating an organ of a deceased family member. Material and Methods: Qualitative research, in depth interviews to eight families that accepted donating an organ of a deceased family member. The interviews were analyzed using the method proposed by Streubert et al and modified by Rivera. Results: The life lessons are described in six comprehensive categories. The painful experience changed towards the feeling that the loved one remains alive. This sensation generated a sense of pride in family members and sensitized them towards the painful experience of other people. Therefore, a desire to help and improve as humans beings was awakened. Conclusions: A compassionate approach towards families donating organs with improve organ donation and humanize the process. Key words: Family; Social values; Tissue and organ procurement

    A new algorithm for the identification of dives reveals the foraging ecology of a shallow-diving seabird using accelerometer data

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    The identification of feeding events is crucial to our understanding of the foraging ecology of seabirds. Technology has made small devices, such as time-depth recorders (TDRs) and accelerometers available. However, TDRs might not be sensitive enough to identify shallow dives, whereas accelerometers might reveal more subtle behaviours at a smaller temporal scale. Due to the limitations of TDRs, the foraging ecology of many shallow-diving seabirds has been poorly investigated to date. We thus developed an algorithm to identify dive events in a shallowdiving seabird species, the Scopoli’s shearwater, using only accelerometer data. The accuracy in the identification of dives using either accelerometers or TDRs was compared. Furthermore, we tested if the foraging behaviour of shearwaters changed during different phases of reproduction and with foraging trip type. Data were collected in Linosa Island (35°51′33″N; 12°51′34″E) from 12 June to 8 September 2015 by deploying accelerometer data loggers on 60 Scopoli’s shearwaters. Four birds were also equipped with TDRs. TDRs recorded only 17.7% of the dives detected by the accelerometers using the algorithm. A total of 82.3% of dives identified by algorithm were too short or shallow to be detected by TDRs. Therefore, TDRs were not accurate enough to detect most of the dives in Scopoli’s shearwaters, which foraged mostly close to the sea surface. Our data showed that birds performed shorter foraging trips and dived more frequently in the early chick-rearing period compared with the late chick-rearing and incubation phases. Furthermore, parents dived more frequently during short foraging trips. Our results suggest that Scopoli’s shearwaters maximised their foraging effort (e.g. number of dives, short trips) during shorter foraging trips and during early chick-rearing

    Age-related changes in anatomical and morphological leaf traits of Wollemia nobilis

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    The results highlight significant variations of Wollemia nobilis leaf traits which reflect age-related changes of the subsequent growth units along the branches. Age-related changes appear in a gradual increase of leaf size from young leaves to old leaves. The LMA increasing from 13.75 g/cm(2) in current year leaves to 24.84 g/cm(2) in 7 year leaves is associated with an increment of the number of lignified elements (vascular tissues, astrosclereids), of hypodermal and epidermal-cuticle structures (cuticle, wax layer) and of oil bodies abundance, which may increase resistance to stress factors. These characteristics highlight that W. nobilis leaves can adapt to variable environmental conditions with a return rate on a larger time-scale since leaves on a branch stay alive for a long time until the branch dies

    Landscape statistics of the low autocorrelated binary string problem

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    The statistical properties of the energy landscape of the low autocorrelated binary string problem (LABSP) are studied numerically and compared with those of several classic disordered models. Using two global measures of landscape structure which have been introduced in the Simulated Annealing literature, namely, depth and difficulty, we find that the landscape of LABSP, except perhaps for a very large degeneracy of the local minima energies, is qualitatively similar to some well-known landscapes such as that of the mean-field 2-spin glass model. Furthermore, we consider a mean-field approximation to the pure model proposed by Bouchaud and Mezard (1994, J. Physique I France 4 1109) and show both analytically and numerically that it describes extremely well the statistical properties of LABSP
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