Dynamic Spatial Auction Market Models with General Cost Mappings

The deregulation of electricity markets in Europe has deeply changed the organization of this sector. Vertically integrated generating companies have been unbundled to create competition and to increase the competitiveness of electricity markets. Directive 96/92/EC was issued by the European Commission to liberalize electricity markets and to pave the way for the creation of the Internal Electricity Market. In particular, this Directive aimed at promoting the competition in the activities of electricity generation and wholesale through the creation of a “marketplace” and the maximization of transparency and efficiency. Competition in European day-ahead electricity markets has been established through auction markets where electricity producers and consumers offer/bid prices and volumes. This paper suggests a dynamic equilibrium model for a system of auction markets linked by transmission lines and subject to energy balance and transmission constraints, such as those characterizing restructured electricity markets. This model is treated as a system of variational inequalities with arbitrary monotone mappings. An inexact splitting type method is proposed to find its solution. Numerical experiments are conducted on the Italian day-ahead electricity market.     

Identity and memory in the modern metropolis: elements for a discussion. The case of Sao Paulo

This article addresses the question of identity and memory in the ever-changing environment of the modern metropolis. It considers the case of Sao Paulo, focusing on a specific borough. It analyses the complex interplay of a borough, seen as a locus of resistance for the preservation of the culture and memory of a group, with the surrounding dynamism of a fast-expanding city. It points to the limited role played by architecture and the built environment in providing useful clues to interpret the metropolitan experience, underlining the need for new methods of inquiry.     

Interplay between Oxidative Stress and Metabolic Derangements in Non-Alcoholic Fatty Liver Disease: The Role of Selenoprotein P

Background: Pathogenetic mechanisms involved in the progression of non-alcoholic fatty liver disease (NAFLD) are complex and multifactorial. We investigated oxidative stress through the measurement of selenoprotein P (SeP) in serum and we explored its relation to metabolic derangements and liver damage in a group of non-diabetic NAFLD subjects. Methods: 57 NAFLD patients underwent a double-tracer oral glucose tolerance test (OGTT). Insulin resistance (IR) components were calculated at baseline as follows: hepatic-IR = (endogenous glucose production*insulin); peripheral-IR = (glucose rate of disappearance(Rd)); adipose-tissue(AT)-IR as Lipo-IR = (glycerol rate of appearance (Ra)*insulin) or AT-IR = (free fatty acids (FFAs)*insulin). The lipid and amino acid (AA) profiles were assessed by gas chromatography–mass spectrometry. SeP levels were measured by enzyme immunosorbent assay. Results: Circulating SeP correlated with insulin (r_S = 0.28), FFAs (r_S = 0.42), glucose Rd (r_S = −0.33) and glycerol Ra (r_S = −0.34); consistently, SeP levels correlated with Lipo-IR and AT-IR (r_S > 0.4). Among the AA and lipid profiles, SeP inversely correlated with serine (r_S = −0.31), glycine (r_S = −0.44) and branched chain AA (r_S = −0.32), and directly correlated with saturated (r_S = 0.41) and monounsaturated FFAs (r_S = 0.40). Hepatic steatosis and fibrosis increased in subjects with higher levels of SeP. In multivariable regression analysis, SeP was associated with the degree of hepatic fibrosis (t = 2.4, p = 0.022). Conclusions: SeP levels were associated with an altered metabolic profile and to the degree of hepatic fibrosis, suggesting a role in the pathogenesis of NAFLD.     

Assessing Blending of Non‐Newtonian Fluids in Static Mixers by Planar Laser‐Induced Fluorescence and Electrical Resistance Tomography

Planar laser‐induced fluorescence (PLIF) and electrical resistance tomography (ERT) were applied simultaneously to monitor the mixing performance of a KM static mixer for the blending of non‐Newtonian fluids of dissimilar rheologies in the laminar regime. The areal distribution method was used to obtain quantitative information from the ERT tomograms and the PLIF images. Comparison of the ERT and PLIF results demonstrates the ability of ERT to detect the mixing performance in cases of poor mixing within the resolution of the measurement, though the accuracy decreases as the condition of perfect mixing is approached. Thus, ERT has the potential to detect poor mixing within the confines of its resolution limit and the required conductivity contrast, providing potential rapid at‐line measurement for industrial practitioners.     

An FT-IR and flow reactor study of the conversion of propane on γ-Al2O3 in oxygen-containing atmosphere

The conversion of propane in the presence of oxygen over alumina has been studied using a fixed bed flow reactor. The interaction of the same catalyst with propane, propene, isopropanol and acetone has also been investigated, with additional gas-phase monitoring, in an FT-IR cell. Alumina looks active in the catalytic conversion of propane to propene, with the production of CO₂, CO, ethylene, methane as the main by-products, depending on the reaction temperature. Higher hydrocarbons such as butenes, butadiene, benzene and toluene are also found.

This reactivity is mainly attributed to the weak but not negligible Brønsted acidity of the surface OH’s of alumina, possibly activating propane in the form of isopropoxides and allowing oligomerization of propene. This shows the detrimental effect of the uncovered alumina support in the case of alumina-supported catalysts for propane oxydehydrogenation and explains the positive role of doping with basic neutralizing agents such as potassium.     

Potential of high pressure homogenization in the control and enhancement of proteolytic and fermentative activities of some Lactobacillus species

Different species of Lactobacillus involved in dairy product fermentation and ripening were considered in order to study the effect of high pressure homogenization (HPH) on: (i) fermentation kinetics of HPH treated cells inoculated in milk; (ii) metabolic profiles; (iii) release of intracellular proteolytic enzymes; and (iv) enhance of the activity of extracellular or cellular wall located proteolytic enzymes. The HPH treatments applied were 50, 100, 150 MPa, 2 cycles at 50 and at 100 MPa. The viability loss did not exceed 1.3 log cfu/ml after the higher treatments applied. The electrophoretic profiles of α- or β-casein incubated with the different cell free filtrates shown that HPH positively affected the proteolytic activity of some strains. Moreover, HPH affected the acidification rates of the milk inoculated with the processed cells and the primary metabolism of some strains. Regarding volatile compounds, ethanol, acetoin and 2-methyl butyric acid were subjected to the major changes when the inoculum had been processed.     

Big data analytics business value and firm performance: linking with environmental context

Previous studies, grounded on the resource based view, have already explored the relationship between the business value that Big Data Analytics (BDA) can bring to firm performance. However, the role played by the environmental characteristics in which companies operate has not been investigated in the literature. We inform the theory, in that direction, via the integration of the contingency theory to the resource based view theory of the firm. This original and integrative model examines the moderating influence of environmental features on the relationship between BDA business value and firm performance. The combination of survey data and secondary financial data on a representative sample of medium and large companies makes possible the statistical validation of our research model. The results offer evidence that BDA business value leads to higher firm performance, namely financial performance, market performance and customer satisfaction. More original is the demonstration that this relationship is stronger in munificent environments, while the dynamism of the environment does not have any moderating effect on the performance of BDA solutions. It means that managers working for firms in markets with a growing demand are in the best position to profit from BDA.