1,748 research outputs found
Data-driven optimal control via linear programming: boundedness guarantees
The linear programming (LP) approach is, together with value iteration and
policy iteration, one of the three fundamental methods to solve optimal control
problems in a dynamic programming setting. Despite its simple formulation,
versatility, and predisposition to be employed in model-free settings, the LP
approach has not enjoyed the same popularity as the other methods. The reason
is the often poor scalability of the exact LP approach and the difficulty to
obtain bounded solutions for a reasonable amount of constraints. We mitigate
these issues here, by investigating fundamental geometric features of the LP
and developing sufficient conditions to guarantee finite solutions with minimal
constraints. In the model-free context, we show that boundedness can be
guaranteed by a suitable choice of dataset and objective function
A study on organogenic potential in the Vitis genus
In order to increase the number of grape genotypes adapted to in vitro manipulation studies, an investigation on the regenerative potentiality in the Vitis genus was conducted on cultivars of Vitis vinifera L., (Barbera, Cabernet franc, Cabernet Sauvignon, Canner Seedless bianco, Chardonnay, Enantio, Moscato bianco, Riesling, Sultana moscato bianco and Sultanina rouge), V. vinifera silvestris G., V. amurensis R., V. armata D. and G., V. riparia M., V. simpsonii M., as well as the rootstocks 110 Richter and Schwarzmann, and the interspecific variety Staufer. Regeneration was induced via direct organogenesis from young leaves, and a relevant genotypic influence on the morphogenic potentiality was observed. Among the 18 different genotypes tested, regeneration occurred with different efficiencies and precocity. Agreeable efficiencies were obtained for Sultana moscato, Riesling, Chardonnay and Cabernet franc, while Enantio and Cabernet Sauvignon were recalcitrant to shoot regeneration. V. armata was the most favourable to this regeneration system
Indagine fitosanitaria nel comprensorio di Sarroch, Villa S. Pietro e Pula (prov. di Cagliari) in relazione all'attività di uno stabilimento petrolifero
A five-year investigation (1988-92) of the phytosanitary situation in the Sarroch, Villa S. Pietro
and Pula areas, belonging to the Cagliari district, where the SARAS-oil company has been operating
for a long time, was carried out.
Various degrees of damage caused by fungi, bacteria, viruses, insects, acari and by abiotic agents
(edaphic and climatic) were detected on trees and herbaceous plants.
Investigations on possible S02 damages by means of phytosanitary observations and chemical
analysis, clearly showed no noxious effects of this gas on both cultivated and spontaneous plants
Imitation and communication skills development in children with pervasive developmental disorders
This study evaluates the correlation between failure to develop spontaneous
imitation and language skills in pervasive developmental disorders. Sixty-four
children between the age of 3 and 8 years were assessed using the Autism
Diagnostic Interview-Revised (ADI-R), the Childhood Autism Rating Scale (CARS),
and the Autism Diagnostic Observation Schedule (ADOS), as well as direct
observation of imitation. The sample was subdivided into a verbal and a
nonverbal group. Analysis of mean scores on the CARS
“imitation” items and of ADI-R “spontaneous
imitation” and “pointing to express
interest” revealed a statistically significant difference between
verbal and nonverbal groups, with more severe impairment/higher scores in the
nonverbal than the verbal group. These results suggest that nonverbal children
have specifically impaired imitation and pointing skills
The Unusually Stable Quaternary Structure of Human Cu,Zn-Superoxide Dismutase 1 Is Controlled by Both Metal Occupancy and Disulfide Status
The eukaryotic copper,zinc superoxide dismutases are remarkably stable dimeric proteins that maintain an intrasubunit disulfide bond in the reducing environment of the cytosol and are active under a variety of stringent denaturing conditions. The structural interplay of conserved disulfide bond and metal-site occupancy in human copper,zinc superoxide dismutase (hSOD1) is of increasing interest as these post-translational modifications are known to dramatically alter the catalytic chemistry, the subcellular localization, and the susceptibility of the protein to aggregation. Using biophysical methods, we find no significant change in the gross secondary or tertiary structure of the demetallated form upon reduction of the disulfide. Interestingly, reduction does lead to a dramatic change in the quaternary structure, decreasing the monomer-to-dimer equilibrium constant by at least four orders of magnitude. This reduced form of hSOD1 is monomeric, even at concentrations well above the physiological range. Either the addition of Zn(II) or the formation of the disulfide leads to a shift in equilibrium that favors the dimeric species, even at low protein concentrations (i.e. micromolar range). We conclude that only the most immature form of hSOD1, i.e. one without any post-translational modifications, favors the monomeric state under physiological conditions. This finding provides a basis for understanding the selectivity of mitochondrial SOD1 import and may be relevant to the toxic properties of mutant forms of hSOD1 that can cause the familial form of amyotrophic lateral sclerosis
Composite nafion-catio3-δ membranes as electrolyte component for pem fuel cells
Manufacturing new electrolytes with high ionic conductivity has been a crucial challenge in the development and large-scale distribution of fuel cell devices. In this work, we present two Nafion composite membranes containing a non-stoichiometric calcium titanate perovskite (CaTiO3−δ ) as a filler. These membranes are proposed as a proton exchange electrolyte for Polymer Electrolyte Membrane (PEM) fuel cell devices. More precisely, two different perovskite concentrations of 5 wt% and 10 wt%, with respect to Nafion, are considered. The structural, morphological, and chemical properties of the composite membranes are studied, revealing an inhomogeneous distribution of the filler within the polymer matrix. Direct methanol fuel cell (DMFC) tests, at 110◦ C and 2 M methanol concentration, were also performed. It was observed that the membrane containing 5 wt% of the additive allows the highest cell performance in comparison to the other samples, with a maximum power density of about 70 mW cm−2 at 200 mA cm−2 . Consequently, the ability of the perovskite structure to support proton carriers is here confirmed, suggesting an interesting strategy to obtain successful materials for electrochemical devices
Legal issues in governing genetic biobanks : the Italian framework as a case study for the implications for citizen’s health through public-private initiatives
Deborah Mascalzoni is funded by RD-Connect under grant agreement number 30544.Peer reviewedPublisher PD
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