413 research outputs found
Reactions of ethanol over CeO2 and Ru/CeO2 catalysts
The reaction of ethanol has been investigated on Ru/CeO2 in steady state conditions as well as with temperature programmed desorption (TPD). High resolution transmission electron microscopy (HRTEM) images indicated that the used catalyst contained Ru particles with a mean size of ca. 1.5 nm well dispersed on CeO2 (of about 12–15 nm in size). Surface uptake of ethanol was measured by changing exposure to ethanol followed by TPD. Saturation coverage is found to be between 0.25 and 0.33 of a monolayer for CeO2 that has been prior heated with O2 at 773 K. The main reactions of ethanol on CeO2 during TPD are: re-combinative desorption of ethanol; dehydrogenation to acetaldehyde; and dehydration to ethylene. The dehydration to ethylene occurs mainly in a small temperature window at about 700 K and it is attributed to ethoxides adsorbed on surface-oxygen defects. The presence of Ru considerably modified the reaction of ceria towards ethanol. It has switched the desorption products to CO, CO2, CH4 and H2. These latter products are typical reforming products. Ethanol steam reforming (ESR) conducted on Ru/CeO2 indicated that optimal reaction activity is at about 673 K above which CO2 production declines (together with that of H2) due to reverse water gas shift. This trend was well captured during ethanol TPD where CO2 desorbed about 50 K below than CO on both oxidized and reduced Ru/CeO2 catalysts.Peer ReviewedPostprint (author's final draft
Home Values and Firm Behavior
The homes of firm owners are an important source of finance for ongoing businesses. We use UK microdata to show that a ÂŁ1 increase in the value of the homes of a firm's directors increases the firm's investment by ÂŁ0.03. This effect is concentrated among firms whose directors' homes are valuable relative to the firm's assets, that are financially constrained, and that have directors who are personally highly levered. An aggregation exercise shows that directors' homes are as important as corporate property for collateral driven fluctuations in aggregate investment demand
Home values and firm behaviour
The homes of those in charge of firms are an important source of finance for ongoing businesses. We use firm level accounting data, transaction level house price data and loan level residential mortgage data from the UK to show that a £1 increase in the value of the residential real estate of a firm’s directors increases the firm’s investment and wage bill by £0.03 each. These effects run through smaller firms and are similar in booms and busts. In aggregate, the homes of firm directors are worth 80% of GDP. Using this, a back of the envelope calculation suggests that a 1% increase in real estate prices leads, through this channel, to up to a 0.28% rise in business investment and a 0.08% rise in total wages paid. We complement this with evidence on how a firm responds to changes in the value of its own corporate real estate; we find that, in aggregate, the residential real estate of directors is at least as important for activity. We use an estimated general equilibrium model to quantify the importance of both types of real estate for the propagation of shocks to the macroeconomy
Type-Decomposition of a Pseudo-Effect Algebra
The theory of direct decomposition of a centrally orthocomplete effect
algebra into direct summands of various types utilizes the notion of a
type-determining (TD) set. A pseudo-effect algebra (PEA) is a (possibly)
noncommutative version of an effect algebra. In this article we develop the
basic theory of centrally orthocomplete PEAs, generalize the notion of a TD set
to PEAs, and show that TD sets induce decompositions of centrally orthocomplete
PEAs into direct summands.Comment: 18 page
The residential collateral channel
We present evidence on a new macroeconomic channel which we call the residential collateral channel. Through this channel, an increase in real estate prices expands firm activity by enabling company directors to utilise their residential property as a source of funds for their business. This channel is a key determinant of investment and job creation, with a £1 increase in the combined residential collateral of a firm’s directors estimated to increase the firm’s investment by £0.02 and total wage costs by £0.02. To show this, we use a unique combination of UK datasets including firm-level accounting data matched with transaction-level house price data and loan-level residential mortgage data. The aggregate value of residential collateral held by company directors (around 70% of GDP) suggests that this channel has important macroeconomic effects. We complement this with further evidence on the corporate collateral channel whereby an increase in real estate prices directly expands firm activity by enabling businesses to borrow more against their corporate real estate. An estimated general equilibrium model with collateral constrained firms is used to quantify the aggregate effects of both channels
Prevalent low-grade dysplasia: the strongest predictor of malignant progression in Barrett's columnar-lined oesophagus
No abstract
Topological Test Spaces
A test space is the set of outcome-sets associated with a collection of
experiments. This notion provides a simple mathematical framework for the study
of probabilistic theories -- notably, quantum mechanics -- in which one is
faced with incommensurable random quantities. In the case of quantum mechanics,
the relevant test space, the set of orthonormal bases of a Hilbert space,
carries significant topological structure. This paper inaugurates a general
study of topological test spaces. Among other things, we show that any
topological test space with a compact space of outcomes is of finite rank. We
also generalize results of Meyer and Clifton-Kent by showing that, under very
weak assumptions, any second-countable topological test space contains a dense
semi-classical test space.Comment: 12 pp., LaTeX 2e. To appear in Int. J. Theor. Phy
Unified Framework for Correlations in Terms of Local Quantum Observables
We provide a unified framework for nonsignalling quantum and classical
multipartite correlations, allowing all to be written as the trace of some
local (quantum) measurements multiplied by an operator. The properties of this
operator define the corresponding set of correlations.We then show that if the
theory is such that all local quantum measurements are possible, one obtains
the correlations corresponding to the extension of Gleason's Theorem to
multipartite systems. Such correlations coincide with the quantum ones for one
and two parties, but we prove the existence of a gap for three or more parties.Comment: 4 pages, final versio
- …