Asymmetric price transmission in EU petroleum markets

This research investigates the determinants of asymmetric price transmission (APT) in European petroleum markets. APT is the faster response of retail prices to cost increases than to cost decreases; resulting in a welfare transfer from consumers to fuel retailers. I investigate APT at 3 different levels: the EU, the UK and at the Birmingham level. First, I examine the incidence of asymmetries in the retail markets of six major EU countries; significant asymmetries are found in all countries except from the UK. The market share data suggest that asymmetries are more important in more concentrated markets; this finding supports the collusion theory. I extend the investigation to 12 EU countries and note that APT is greater in diesel markets. The cross-country analysis suggests that vertical and horizontal concentration at least partly explains the degree of asymmetry. I provide evidence justifying scrutiny over retail markets’ pricing and structure. Second daily data unveil the presence of APT in the UK fuel markets. I use break tests to identify segments with different pricing regimes. Two main types of periods are identified: periods of rising oil price exhibit significant asymmetries whilst periods of recession do not. Our results suggest that oligopolistic coordination between retailers generate excess rents during periods of rising oil price whilst the coordination fails due to price wars when oil prices are going downwards. Finally I investigate the pricing behaviour of petroleum retailers in the Birmingham (UK) area for 2008. Whilst the market structure data reveals that the horizontal concentration is higher than the national UK average, I find no evidence of APT. In contrast, I find that retail prices are sticky upwards and downwards and that firms with market power (majors and supermarkets) adjust their prices slower than other firms.

Price discrimination in asymmetric Cournot oligopoly

In this article we examine the eects of third degree price discrimination in asymmetric Cournot oligopolies. We show that the average price is not affected by the extent of price discrimination. We nd that the asymmetry between firms is reflected only by the output produced for the lowest-valuation consumers and firms produce equal quantities to the other consumer groups.

Price discrimination in asymmetric Cournot oligopoly

In this article we examine the eects of third degree price discrimination in asymmetric Cournot oligopolies. We show that the average price is not affected by the extent of price discrimination. We nd that the asymmetry between firms is reflected only by the output produced for the lowest-valuation consumers and firms produce equal quantities to the other consumer groups.

Endogenous timing of moves in an asymmetric price-setting duopoly

This paper adds to the growing literature on endogenous timing of decisions in duopolies. We show for a price-setting duopoly game with sufficiently asymmetric and strictly convex cost functions that the less efficient firm moves first while the more efficient moves second with a higher price than the less efficient firm.

Asymmetric syntheses of analogs of kainic acid

Kainic acid has been used for nearly 50 years as a tool in neuroscience due to its pronounced neuroexcitatory properties. However, the significant price increase of kainic acid resulting from the disruption in the supply from its natural source, the alga Digenea Simplex, as well as inefficient synthesis of kainic acid, call for the exploration of functional mimics of kainic acid that can be synthesized in a simpler way. Aza kainoids analog could be one of them. The unsubstituted aza analog of kainoids has demonstrates its ability as an ionotropic glutamate receptor agonist and showed affinity in the chloride dependent glutamate (GluCl) binding site. This opened a question of the importance of the presence of one nitrogen or both nitrogens in the aza kainoid analogs for binding to glutamate receptors. Therefore, two different pyrrolidine analogs of kainic acid, trans -4-(carboxymethyl)pyrrolidine-3-carboxylic acid and trans -2-carboxy-3-pyrrolidineacetic acid, were synthesized through multi-step sequences. The lack of the affinity of both pyrrolidine analogs in GluCl binding site indicated that both nitrogens in aza kainoid analogs are involved in hydrogen bonding with receptors, significantly enhancing their affinity in GluCl binding site. Another potential functional mimic of kainic acid is isoxazolidine analogs of kainoids whose skeleton can be constituted directly via a 1, 3 dipolar cycloaddition as the key step. The difficulty in synthesizing N-unsubstituted isoxazolidines when applying such common protecting groups as alkyl, phenyl and benzyl groups, and the requirement of a desired enantioselectivity due to the three chiral ceneters in kainic acid, pose great challenges. Hence, several different protected nitrones were studied to establish that diphenylmethine nitrone may be a good candidate as the dipole in that the generated isoxazolidines can be deprotected in mild conditions with high yields. Our investigations also indicated that the exo/endo selectivity of the 1, 3 dipolar cycloaddition can be controlled by Lewis acids, and that the application of a directing group in dipolarophiles can accomplish a satisfied enantioselectivity. Those results demonstrated the synthesis of isoxazoldines analogs of kainic acid is very promising.

Asymptotic Theory for Extended Asymmetric Multivariate GARCH Processes

The paper considers various extended asymmetric multivariate conditional volatility models, and derives appropriate regularity conditions and associated asymptotic theory. This enables checking of internal consistency and allows valid statistical inferences to be drawn based on empirical estimation. For this purpose, we use an underlying vector random coefficient autoregressive process, for which we show the equivalent representation for the asymmetric multivariate conditional volatility model, to derive asymptotic theory for the quasi-maximum likelihood estimator. As an extension, we develop a new multivariate asymmetric long memory volatility model, and discuss the associated asymptotic properties.

Asymmetric Synthesis and Absolute Configuration of (+)- and (–)-Perhexiline

Peer reviewed

Asymmetric Synthesis and Absolute Configuration of (+)- and (–)-Perhexiline

Peer reviewed

Asymmetric 3D video coding based on regions of perceptual relevance

This dissertation presents a study and experimental research on asymmetric coding of stereoscopic video. A review on 3D technologies, video formats and coding is rst presented and then particular emphasis is given to asymmetric coding of 3D content and performance evaluation methods, based on subjective measures, of methods using asymmetric coding. The research objective was de ned to be an extension of the current concept of asymmetric coding for stereo video. To achieve this objective the rst step consists in de ning regions in the spatial dimension of auxiliary view with di erent perceptual relevance within the stereo pair, which are identi ed by a binary mask. Then these regions are encoded with better quality (lower quantisation) for the most relevant ones and worse quality (higher quantisation) for the those with lower perceptual relevance. The actual estimation of the relevance of a given region is based on a measure of disparity according to the absolute di erence between views. To allow encoding of a stereo sequence using this method, a reference H.264/MVC encoder (JM) has been modi ed to allow additional con guration parameters and inputs. The nal encoder is still standard compliant. In order to show the viability of the method subjective assessment tests were performed over a wide range of objective qualities of the auxiliary view. The results of these tests allow us to prove 3 main goals. First, it is shown that the proposed method can be more e cient than traditional asymmetric coding when encoding stereo video at higher qualities/rates. The method can also be used to extend the threshold at which uniform asymmetric coding methods start to have an impact on the subjective quality perceived by the observers. Finally the issue of eye dominance is addressed. Results from stereo still images displayed over a short period of time showed it has little or no impact on the proposed method.

A long non-coding RNA targets microRNA miR-34a to regulate colon cancer stem cell asymmetric division.

The roles of long non-coding RNAs (lncRNAs) in regulating cancer and stem cells are being increasingly appreciated. Its diverse mechanisms provide the regulatory network with a bigger repertoire to increase complexity. Here we report a novel LncRNA, Lnc34a, that is enriched in colon cancer stem cells (CCSCs) and initiates asymmetric division by directly targeting the microRNA miR-34a to cause its spatial imbalance. Lnc34a recruits Dnmt3a via PHB2 and HDAC1 to methylate and deacetylate the miR-34a promoter simultaneously, hence epigenetically silencing miR-34a expression independent of its upstream regulator, p53. Lnc34a levels affect CCSC self-renewal and colorectal cancer (CRC) growth in xenograft models. Lnc34a is upregulated in late-stage CRCs, contributing to epigenetic miR-34a silencing and CRC proliferation. The fact that lncRNA targets microRNA highlights the regulatory complexity of non-coding RNAs (ncRNAs), which occupy the bulk of the genome.

Asymmetric oxidation of sulfides

This review discusses synthesis of enantiopure sulfoxides through the asymmetric oxidation of prochiral sulfides. The use of metal complexes to promote asymmetric sulfoxidation is described in detail, with a particular emphasis on the synthesis of biologically active sulfoxides. The use of non-metal-based systems, such as oxaziridines, chiral hydroperoxides and peracids, as well as enzyme-catalyzed sulfoxidations is also examined.

Ultrahigh Purcell factor in low-threshold nanolaser based on asymmetric hybrid plasmonic cavity

A low-threshold nanolaser with all three dimensions at the subwavelength scale is proposed and investigated. The nanolaser is constructed based on an asymmetric hybrid plasmonic F-P cavity with Ag-coated end facets. Lasing characteristics are calculated using finite element method at the wavelength of 1550 nm. The results show that owing to the low modal loss, large modal confinement factor of the asymmetric plasmonic cavity structure, in conjunction with the high reflectivity of the Ag reflectors, a minimum threshold gain of 240 cm−1 is predicted. Furthermore, the Purcell factor as large as 2518 is obtained with optimized structure parameters to enhance rates of spontaneous and stimulated emission.

Asymmetric electrocyclic reactions

This critical review offers an overview of asymmetric electrocyclic processes, where diastereo- or enantioselectivity is a consequence of the influence of a chiral component (be it substrate or catalyst) on the electrocyclic bond-forming process (195 references). © 2011 The Royal Society of Chemistry.

Asymmetric hydrogen flame in a heated micro-channel: role of Darrieus-Landau and thermal-diffusive instabilities

Present work examines numerically the asymmetric behavior of hydrogen/air flame in a micro-channel subjected to a non-uniform wall temperature distribution. A high resolution (with cell size of 25 μm × 25 μm) of two-dimensional transient Navier–Stokes simulation is conducted in the low-Mach number formulation using detailed chemistry evolving 9 chemical species and 21 elementary reactions. Firstly, effects of hydrodynamic and diffusive-thermal instabilities are studied by performing the computations for different Lewis numbers. Then, the effects of preferential diffusion of heat and mass transfer on the asymmetric behavior of the hydrogen flame are analyzed for different inlet velocities and equivalence ratios. Results show that for the flames in micro-channels, interactions between thermal diffusion and molecular diffusion play major role in evolution of a symmetric flame into an asymmetric one. Furthermore, the role of Darrieus–Landau instability found to be minor. It is also found that in symmetric flames, the Lewis number decreases behind the flame front. This is related to the curvature of flame which leads to the inclination of thermal and mass fluxes. The mass diffusion vectors point toward the walls and the thermal diffusion vectors point toward the centerline. Asymmetric flame is observed when the length of flame front is about 1.1–1.15 times of the channel width.