280 research outputs found
Dynamic multilevel modelling of industrial energy demand in Europe
Previous studies of industry level energy demand have not accounted for the hierarchical nesting of industries within a system that also adequately allows for country specific determinants of energy demand. The principal contribution of this paper is therefore to analyse energy demand for European industries over the period 1995â2009 using a dynamic multilevel model that accounts for this hierarchical data structure. Among other things, we find, firstly, that our dynamic multilevel model suggests that if industry income and the industry energy price increase by 10%, long run energy demand will increase by 8.1% and fall by 6.8%, respectively. Secondly, we find that the corresponding long run income and price elasticities are substantially larger in a standard dynamic model of industry level energy demand which does not account for the hierarchical data structure. Our results therefore suggest that not accounting for the hierarchical data structure results in unreliable estimates of energy demand elasticities. From a policy perspective we argue that it is imperative that future industry level energy demand studies account for the hierarchical structure of the data. This is to prevent energy policy making being based on industry level evidence that substantially inflates the responsiveness of long run energy demand to income and price changes
The role of inefficiency in a productivity puzzle: regional evidence for Great Britain
From around the 2008 crisis there has been a marked slowdown in UK productivity. This has been referred to as a productivity puzzle as there is no consensus on the key explanations for this slowdown. Using data for all the 168 International Territorial Level 3 areas in Great Britain (2004â2020), we make two empirical contributions to the literature on this puzzle. First, we are the first to analyze this productivity puzzle using a stochastic frontier model to account for technical inefficiency. Second, to aid policymakers we uncover the areas that represent spatial total factor productivity (TFP) growth hubs, spokes, leaders and followers. Of the components of TFP growth (growth rates of technical change, returns to scale and efficiency), we find that Britain's productivity slowdown can be more specifically described as a rise in inefficiency
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Compound ellipsoidal focusing system for fusion lasers
Isentropic compression of laser fusion targets requires highly uniform illumination over the entire target surface, and near normal incidence. For a two beam laser, this is best achieved using a fast catadioptric system. In designing such a system, the total thickness of refracting material must be minimized, to avoid loss of optical quality through small scale self focusing. Such a system is being fabricated for use with the ARGUS laser. It consists of a pair of nested ellipsoidal reflectors, coupled with an aspheric doublet refracting element which provides uniform illumination for the specified laser beam profile. (auth
COVID-19 mortalities in England and Wales and the Peltzman offsetting effect
There are two approaches to measuring COVID-19 deathsââCOVID associated deathsâ and âexcess deathsâ. An excess deaths framework is preferable, as there is measurement error in COVID associated deaths, due to issues relating to imperfect information about deaths that are directly attributable to COVID-19. The standard measure of excess deaths (comparison of deaths to a 5-year average) is subject to an omitted variables problem, as it attributes the entirety of the variation in mortality to COVID-19. We propose a method to estimate a refined measure of COVID-19 excess deaths in England and Wales that addresses the omitted impact of the first blanket lockdown. Using the counterfactual, we obtain a first stage estimate of excess deaths. In the second stage, this is decomposed into estimates of a refined measure of COVID-19 excess deaths and the excess mortality impact of lockdown. Our results suggest: (i) a refined estimate of mean weekly COVID-19 excess deaths that is 63% of standard excess deaths; and (ii) a positive net excess mortality impact of the lockdown. We make a case that (ii) is due to the Peltzman offsetting effect, i.e. the intended mortality impact of the lockdown was more than offset by the unintended impact
Spatio-temporal patterns in the Hantavirus infection
We present a model of the infection of Hantavirus in deer mouse, Peromyscus
maniculatus, based on biological observations of the system in the North
American Southwest. The results of the analysis shed light on relevant
observations of the biological system, such as the sporadical disappearance of
the infection, and the existence of foci or ``refugia'' that perform as
reservoirs of the virus when environmental conditions are less than optimal.Comment: 6 pages, 5 inlined figures, RevTeX 4 forma
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Lens and mirror design via the principal surface
The problem of optical design is stated as follows: Given a principal surface r(), and a maximum focal angle /sub m/, find the pair of optical surfaces for which diffraction limited focusing is achieved. It is shown that specification of r() and /sub m/ uniquely determines the lens design to within a scale factor, given the refractive index of the lens. It is further shown that one straightforward Runge-Kutta integration routine generates both surfaces for either a lens or a pair of mirror surfaces. The complete family of aplanatic lenses is described. Deviation from sphericity is discussed, as well as the possibility of realizing the specified lens designs. The family of lenses which map uniform incident intensity into uniform illumination about the focus is also described. Extension of the method to off-axis aberrations is considered. (auth
The UK productivity puzzle: a survey of the literature and expert views
Since 2008, the UKâs productivity has stagnated, leading to the widely debated âproductivity puzzleâ. Understanding this phenomenon and its drivers is crucial for managers and policymakers. This article summarises theoretical and empirical literature on the determinants of productivity in general terms, as well as their relevance to the UKâs productivity performance. It also discusses to what extent the findings from a survey of leading UK academic experts on productivity provide support for the existing theoretical and empirical evidence on this topic, and help identify and validate the most important factors explaining the UKâs productivity slowdown since 2008. The combination of our literature review and survey findings suggests that key determinants of the UKâs productivity slowdown include: insufficient investment; insufficient quality of infrastructure; limitations in human capital stock; and management quality issues
Therapeutic Hypothermia for Neonatal Encephalopathy Results in Improved Microstructure and Metabolism in the Deep Gray Nuclei
BACKGROUND AND PURPOSE: Therapeutic hypothermia has reduced morbidity and mortality and is associated with a lower burden of lesions on conventional imaging in NE. However, its effects on brain microstructure and metabolism have not been fully characterized. We hypothesized that therapeutic hypothermia improves measures of brain microstructure and metabolism. MATERIALS AND METHODS: Forty-one neonates with moderate/severe NE (29 treated with hypothermia, 12 nontreated) and 12 healthy neonates underwent MR imaging, DTI, and (1)H-MR spectroscopy. MR imaging scans were scored by the predominant pattern of brain injury: normal, watershed, and BG/thalamus. ADC, FA, Lac:NAA, and NAA:Cho values from bilateral BG and thalamus ROIs were averaged. T test and linear regression analysis were used to determine the association between hypothermia and MR imaging quantitative measures. RESULTS: Conventional MR imaging findings were normal in 41% of treated neonates; all nontreated neonates had brain injury. Values of MR imaging metrics were closer to normal in treated neonates compared with nontreated neonates: ADC was 63% higher in the BG and 116% higher in the thalamus (both P < .05), and Lac:NAA was 76% lower (P = .04) in the BG. Treated neonates with normal MR imaging findings had normal (1)H-MR spectroscopy metabolites, and ADC was higher by 35% in the thalamus (P = .03) compared with healthy neonates. CONCLUSIONS: Therapeutic hypothermia may reduce disturbances of brain metabolism and preserve its microstructure in the setting of NE, possibly by minimizing cytotoxic edema and cell death. Long-term follow-up studies are required to determine whether early post-treatment DTI and (1)H-MR spectroscopy will be useful biomarkers of treatment response
An updated analysis of NN elastic scattering data to 1.6 GeV
An energy-dependent and set of single-energy partial-wave analyses of
elastic scattering data have been completed. The fit to 1.6~GeV has been
supplemented with a low-energy analysis to 400 MeV. Using the low-energy fit,
we study the sensitivity of our analysis to the choice of coupling
constant. We also comment on the possibility of fitting data alone. These
results are compared with those found in the recent Nijmegen analyses. (Figures
may be obtained from the authors upon request.)Comment: 17 pages of text, VPI-CAPS-7/
Tilt order parameters, polarity and inversion phenomena in smectic liquid crystals
The order parameters for the phenomenological description of the smectic-{\it
A} to smectic-{\it C} phase transition are formulated on the basis of molecular
symmetry and structure. It is shown that, unless the long molecular axis is an
axis of two-fold or higher rotational symmetry, the ordering of the molecules
in the smectic-{\it C} phase gives rise to more than one tilt order parameter
and to one or more polar order parameters. The latter describe the indigenous
polarity of the smectic-{\it C} phase, which is not related to molecular
chirality but underlies the appearance of spontaneous polarisation in chiral
smectics. A phenomenological theory of the phase transition is formulated by
means of a Landau expansion in two tilt order parameters (primary and
secondary) and an indigenous polarity order parameter. The coupling among these
order parameters determines the possibility of sign inversions in the
temperature dependence of the spontaneous polarisation and of the helical pitch
observed experimentally for some chiral smectic-{\it } materials. The
molecular interpretation of the inversion phenomena is examined in the light of
the new formulation.Comment: 12 pages, 5 figures, RevTe
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