Database Repairs and Analytic Tableaux

In this article, we characterize in terms of analytic tableaux the repairs of inconsistent relational databases, that is databases that do not satisfy a given set of integrity constraints. For this purpose we provide closing and opening criteria for branches in tableaux that are built for database instances and their integrity constraints. We use the tableaux based characterization as a basis for consistent query answering, that is for retrieving from the database answers to queries that are consistent with respect to the integrity constraints.     

Preferential CO oxidation over Pt/3A zeolite catalysts in H2-rich gas for fuel cell application

Even traces of CO in the hydrogen-rich gas fed to proton exchange membrane fuel cells (PEMFC) poison the platinum anode electrode and dramatically decrease the cell power output. In this work, several 1%Pt catalysts, all on 3A-type zeolite support, were prepared starting from different precursors and employing different methods: cation exchange (CE), wet impregnation (WI) and incipient wetness impregnation (IWI). The catalysts were characterised in terms of platinum dispersion and tested under realistic conditions in the quest of a catalyst for the removal of CO via the CO preferential oxidation (CO-PROX) reaction. The best catalytic performance was shown by the 1%Pt–3A catalyst prepared by IWI starting from Pt(NH₃)₄Cl₂ as a precursor, thanks to its highest platinum dispersion.     

Mechanism of erythrocyte accumulation of methylation inhibitor S-adenosylhomocysteine in uremia

We have recently demonstrated that methyl esterification of erythrocyte membrane proteins, a reaction involved in recognition and repair of specifically damaged proteins, is impaired in uremia. This is accompanied by a significant increase in intracellular S-adenosylhomocysteine (AdoHcy), a potent inhibitor of methyltransferases. AdoHcy accumulation is normally prevented by its enzymatic hydrolysis to homocysteine (Hcy) and adenosine, a reversible reaction catalyzed by AdoHcy hydrolase. To assess the contribution that Hcy offers in the elevation of AdoHcy, we measured plasma and red blood cell Hcy, AdoHcy, adenosine, and S-adenosylmethionine (AdoMet) intracellular concentrations, as well as RBC AdoHcy hydrolase specific activity, in standard hemodialysis patients and normal subjects. Plasma and red blood cell Hcy levels are significantly higher in the dialysis group, and are positively correlated to AdoHcy levels. Adenosine and AdoMet levels, and AdoHcy hydrolase specific activity are not significantly different between the two groups. The enzymatic formation of labeled AdoHcy from Hcy and tracer adenosine appears to be significantly increased, in vitro, in erythrocytes from both control and uremic patients, when 50 microM Hcy (concentration comparable to plasma levels actually found in vivo in uremic patients) is added to the incubation medium. When erythrocytes from uremic patients are incubated in vitro in absence of Hcy, a significant reduction of intracellular AdoHcy is observed with time compared to identical samples incubated in presence of 50 microM Hcy, with a T1/2 of approximately 270 minutes. The results allow us to conclude that plasma and red cell Hcy levels actually found in uremia can be effectively responsible for the intracellular accumulation of the toxic compound AdoHcy.     

Tableau-based characterization and theorem proving for default logic

In this paper, we present a new method for computing extensions and for deriving formulae from a default theory. It is based on the semantic tableaux method and works for default theories with a finite set of defaults that are formulated over a decidable subset of first-order logic. We prove that all extensions (if any) of a default theory can be produced by constructing the semantic tableau ofone formula built from the general laws and the default consequences. This result allows us to describe an algorithm that provides extensions if there are any, and to decide if there are none. Moreover, the method gives a necessary and sufficient criterion for the existence of extensions of default theories with finitely many defaults provided they are formulated on a decidable subset of FOL.This work was completed while the author was at CNRS, Marseille.     

Regional business cycles in Italy

There is clear evidence for differences in the structure of the Italian regional business cycle in the period 1951-2004: the relationship with the national business cycle is closer in the North than in the South. The interaction between regional cycles shows considerable variation over time. There is a change in the timing of the turning points and the strength of the relationship. In the 1950s and the early 1960s, the cycle in the North leads the cycle in the South. Comovement is strongest in the period 1965-1975. After 1975, the cycles start to drift out of phase, again with the North leading the South.     

Long-term effects of acceleration on the social-emotional adjustment of mathematically precocious youths.

The study of Mathematically Precocious Youth (SMPY) identified over 2,000 12–14 year-olds who scored as well as a random sample of high school females on the Scholastic Aptitude Test. SMPY encouraged these students to accelerate their education; over 50% did. Their social development at age 18 and at age 23 was then assessed. We investigated the effects of amount and type of educational acceleration (grade skipping and subject matter) on psychosocial indices (self-esteem, locus of control, self-acceptance/identity, and social interaction). No gender differences were significant. Accelerants as well as nonaccelerants reported high self-esteem and internal locus of control. Acceleration did not affect social interactions or self-acceptance/identity and it also did not relate to social and emotional difficulties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mating Disruption of Plodia interpunctella in Small-Scale Plots: Effects of Pheromone Blend, Emission Rates, and Population Density

An indoor mating disruption experiment was performed on the stored-product pest Plodia interpunctella. The female of this species emits a four-component pheromone blend consisting of Z9,E12–14 : OAc, Z9,E12–14 : OH, Z9,E12–14 : Ald, and Z9–14 : OAc. Mating of Plodia interpunctella was disrupted up to 93% by using synthetic pheromone in small-scale plot experiments. The study was performed in 2.5 m × 2.5 m × 2.5 m polythene cubicles housed in a greenhouse, and pheromones were released by MSTRS spraying every 15~min. The disruption effect was tested at different doses 0.075, 0.75, and 3.75 mg/spray (corresponding to 5, 50, and 250 g/min), different pheromone formulas (one-component (Z9,E12–14 : OAc) and four-component), and at different population densities (10, 20, and 30 individuals, equivalent to 0.32, 0.64, and 0.96 individuals/m²). The moths were released into the cubicles and recaptured 24 hr later. The females were checked for spermatophore presence indicating successful mating. The mating was significantly suppressed in all treatments compared to the control. There was, however, no difference in mating activity between the one-component and four-component disruptants. In addition, EAG measurements were conducted with a portable device to keep track of aerial concentrations of pheromone. The results show that the one-component formula disrupts mating as efficiently as the more complete four-component blend at doses applied in this study. This fact improves the prospects for mating disruption of indoor pyralids, since many pyralid species share the major component in their pheromones, and, thus, can probably be controlled simultaneously by using this compound only.     

Agricultural investment and international land deals: evidence from a multi-country study in Africa

Recent spikes in world food and energy prices have fostered renewed momentum for agricultural investment in lower and middle-income countries. Governments in some food-importing countries are promoting the acquisition of land overseas as a means to ensure long-term national food security. Businesses are recognizing new opportunities for strong returns from international investments in agriculture for food, fuel and other agricultural commodities. Dubbed ‘land grabs’ in the media, land-based investments have kindled much international debate, in which strong positions are taken on the impacts of such investments on environment, rights, sovereignty, livelihoods, development and conflict at local, national and international levels. Depending on how they are structured, agricultural investments may deliver local benefits and include small-scale producers in value chains, or carry environmental and social risks that fall disproportionately on local people. Vigorous public debate in recipient countries, effective screening of proposed investments, including robust environmental and social impact assessments, secure local land and resource rights, local voice in decision-making, skillfully negotiated and regulated contracts and effective policy incentives for business models that favor working with local farmers over large plantations can help make the renewed momentum in agricultural investment work for development.     

Mitochondrial Aminoacyl-tRNA Synthetase and Disease: The Yeast Contribution for Functional Analysis of Novel Variants

In most eukaryotes, mitochondrial protein synthesis is essential for oxidative phosphorylation (OXPHOS) as some subunits of the respiratory chain complexes are encoded by the mitochondrial DNA (mtDNA). Mutations affecting the mitochondrial translation apparatus have been identified as a major cause of mitochondrial diseases. These mutations include either heteroplasmic mtDNA mutations in genes encoding for the mitochondrial rRNA (mtrRNA) and tRNAs (mttRNAs) or mutations in nuclear genes encoding ribosomal proteins, initiation, elongation and termination factors, tRNA-modifying enzymes, and aminoacyl-tRNA synthetases (mtARSs). Aminoacyl-tRNA synthetases (ARSs) catalyze the attachment of specific amino acids to their cognate tRNAs. Differently from most mttRNAs, which are encoded by mitochondrial genome, mtARSs are encoded by nuclear genes and then imported into the mitochondria after translation in the cytosol. Due to the extensive use of next-generation sequencing (NGS), an increasing number of mtARSs variants associated with large clinical heterogeneity have been identified in recent years. Being most of these variants private or sporadic, it is crucial to assess their causative role in the disease by functional analysis in model systems. This review will focus on the contributions of the yeast Saccharomyces cerevisiae in the functional validation of mutations found in mtARSs genes associated with human disorders.