213 research outputs found
GĂȘnesis de espodossolos amazĂŽnicos: um estudo sobre a estrutura e a mobilidade da matĂ©ria orgĂąnica.
Characterization of organic matter in spodosol amazonian by fluorescence spectroscopy.
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Assessing future vent opening locations at the Somma-Vesuvio volcanic complex:1. A new information geodatabase with uncertainty characterizations
This study presents new and revised data sets about the spatial distribution of past volcanic vents, eruptive fissures, and regional/local structures of the SommaâVesuvio volcanic system (Italy). The innovative features of the study are the identification and quantification of important sources of uncertainty affecting interpretations of the data sets. In this regard, the spatial uncertainty of each feature is modeled by an uncertainty area, i.e., a geometric element typically represented by a polygon drawn around points or
lines. The new data sets have been assembled as an updatable geodatabase that integrates and
complements existing databases for SommaâVesuvio. The data are organized into 4 data sets and stored as
11 feature classes (points and lines for feature locations and polygons for the associated uncertainty areas),
totaling more than 1700 elements. More specifically, volcanic vent and eruptive fissure elements are
subdivided into feature classes according to their associated eruptive styles: (i) Plinian and subâPlinian
eruptions (i.e., largeâ or mediumâscale explosive activity); (ii) violent Strombolian and continuous ash
emission eruptions (i.e., smallâscale explosive activity); and (iii) effusive eruptions (including eruptions from
both parasitic vents and eruptive fissures). Regional and local structures (i.e., deep faults) are represented as
linear feature classes. To support interpretation of the eruption data, additional data sets are provided for
SommaâVesuvio geological units and caldera morphological features. In the companion paper, the data
presented here, and the associated uncertainties, are used to develop a first vent opening probability map for the SommaâVesuvio caldera, with specific attention focused on large or medium explosive events.Published4336-43566V. PericolositĂ vulcanica e contributi alla stima del rischioJCR Journa
Fractal behavior of humic substances evaluated by confocal laser scanning microscopy (CLSM) and fluorescence lifetime imaging.
A novel INDEL mutation in the EDA gene resulting in a distinct X- linked hypohidrotic ectodermal dysplasia phenotype in an Italian family
A novel INDEL mutation in theEDA gene resulting in a distinctX- linked hypohidroticectoder mal dysplasia phenotypein an Italian familyEditorX-Linked Hypohidrotic Ectodermal Dysplasia (XL-HED; MIM305100) is characterized by hypodontia, misshaped teeth, hypo-hidrosis, sparse hair, peculiar facial features,1,2and occurs in lessthan 1 in every 100.000 individuals.1XL-HED is caused bymutations in the Ectodysplasin-A (EDA) gene located at Xq12-q13 with more than 100 causative mutations reported todate.1,3,4The identification of disease-causing mutations con-firms the diagnosis, however, does not automatically imply agenotype\u2013phenotype correlation
Gun1 controls accumulation of the plastid ribosomal protein S1 at the protein level and interacts with proteins involved in plastid protein homeostasis
Developmental or metabolic changes in chloroplasts can have profound effects on the rest of the plant cell. Such intracellular responses are associated with signals that originate in chloroplasts and convey information on their physiological status to the nucleus, which leads to large-scale changes in gene expression (retrograde signaling). A screen designed to identify components of retrograde signaling resulted in the discovery of the so-called genomes uncoupled (gun) mutants. Genetic evidence suggests that the chloroplast protein GUN1 integrates signals derived from perturbations in plastid redox state, plastid gene expression, and tetrapyrrole biosynthesis (TPB) in Arabidopsis (Arabidopsis thaliana) seedlings, exerting biogenic control of chloroplast functions. However, the molecular mechanism by which GUN1 integrates retrograde signaling in the chloroplast is unclear. Here we show that GUN1 also operates in adult plants, contributing to operational control of chloroplasts. The gun1 mutation genetically interacts with mutations of genes for the chloroplast ribosomal proteins S1 (PRPS1) and L11. Analysis of gun1 prps1 lines indicates that GUN1 controls PRPS1 accumulation at the protein level. The GUN1 protein physically interacts with proteins involved in chloroplast protein homeostasis based on coimmunoprecipitation experiments. Furthermore, yeast two-hybrid and bimolecular fluorescence complementation experiments suggest that GUN1 might transiently interact with several TPB enzymes, including Mg-chelatase subunit D (CHLD) and two other TPB enzymes known to activate retrograde signaling. Moreover, the association of PRPS1 and CHLD with protein complexes is modulated by GUN1. These findings allow us to speculate that retrograde signaling might involve GUN1-dependent formation of protein complexes
Improved Drought Stress Response in Alfalfa Plants Nodulated by an IAA Over-producing Rhizobium Strain
The drought\u2013stress response in plant involves the cross-talk between abscisic acid
(ABA) and other phytohormones, such as jasmonates and ethylene. The auxin indole-3-
acetic acid (IAA) plays an integral part in plant adaptation to drought stress. Investigation
was made to see how the main auxin IAA interacted with other plant hormones under
water stress, applied through two different growth conditions (solid and hydroponic).
Medicago sativa plants nodulated by the Ensifer meliloti wild type 1021 (Ms-1021) and
its IAA-overproducing RD64 derivative strains (Ms-RD64) were subjected to drought
stress, comparing their response. When the expression of nifH gene and the activity
of the nitrogenase enzyme were measured after stress treatments, Ms-RD64 plants
recorded a significantly weaker damage. These results were correlated with a lower
biomass reduction, and a higher Rubisco protein level measured for the Ms-RD64-
stressed plants as compared to the Ms-1021-stressed ones. It has been verified that the
stress response observed for Ms-RD64-stressed plants was related to the production
of greater amount of low-molecular-weight osmolytes, such as proline and pinitol,
measured in these plants. For the Ms-RD64 plants the immunoblotting analysis of
thylakoid membrane proteins showed that some of the photosystem proteins increased
after the stress. An increased non-photochemical quenching after the stress was also
observed for these plants. The reduced wilting signs observed for these plants were
also connected to the significant down-regulation of the MtAA03 gene involved in
the ABA biosynthesis, and with the unchanged expression of the two genes (Mt-
2g006330 and Mt-8g095330) of ABA signaling. When the expression level of the
ethylene-signaling genes was evaluated by qPCR analysis no significant alteration of the
key positive regulators was recorded for Ms-RD64-stressed plants. Coherently, these
plants accumulated 40% less ethylene as compared to Ms-1021-stressed ones. The
results presented herein indicate that the variations in endogenous IAA levels, triggered
by the overproduction of rhizobial IAA inside root nodules, positively affected drought
stress response in nodulated alfalfa plants
Active debris multi-removal mission concept based on hybrid propulsion
During the last 40 years, the mass of the artificial objects in orbit increased quite steadily at the rate of about 145 metric tons annually, leading to about 7000 metric tons. Most of the cross-sectional area and mass (97% in low Earth orbit) is concentrated in about 4500 intact abandoned objects plus a further 1000 operational spacecraft. Analyses have shown that the most effective mitigation strategy should focus on the disposal of objects with larger cross-sectional area and mass from densely populated orbits. Recent NASA results have shown that the worldwide adoption of mitigation measures in conjunction with active yearly removal of approximately 0.2â0.5% of the abandoned objects would stabilize the debris population. Targets would have typical masses between 500 and 1000 kg in the case of spacecraft, and of more than 1000 kg for rocket upper stages. In the case of Cosmos-3M second stages, more than one object is located nearly in the same orbital plane. This provides the opportunity of multi-removal missions, more suitable for yearly removal rate and cost reduction needs. This paper deals with the feasibility study of a mission for the active removal of large abandoned objects in low Earth orbit. In particular, a mission is studied in which the removal of two Cosmos-3M second stages, that are numerous in low Earth orbit, is considered. The removal system relies on a Chaser spacecraft which performs rendezvous maneuvers with the two targets. The first Cosmos-3M stage is captured and an autonomous de-orbiting kit, carried by the Chaser, is attached to it. The de-orbiting kit includes a Hybrid Propulsion Module, which is remotely ignited to perform stage disposal and controlled reentry after Chaser separation. Then, the second Cosmos-3M stage is captured and, in this case, the primary propulsion system of the Chaser is used for the disposal of the mated configuration. Critical mission aspects and related technologies are investigated at a preliminary level. In particular, an innovative electro-adhesive system for target capture, a mechanical system for the hard docking with the target and a hybrid propulsion system suitable for rendezvous, de-orbiting and controlled reentry operations are analyzed. This is performed on the basis of a preliminary mission profile, in which suitable rendezvous and disposal strategies have been considered and investigated by numerical analysis. A preliminary system mass budget is also performed, showing that the Chaser overall mass is about 1350 kg, including a primary propulsion system of about 300 kg and a de-orbiting kit with a mass of about 200 kg. This system is suitable to be launched with VEGA, actually the cheapest European space launcher
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