5,859 research outputs found
GOES imagery fills gaps in Montserrat volcanic cloud observations
GOES satellite imagery offers great potential to lessen the risk of volcanic ash clouds to aviation, and the situation at Montserrat in the Caribbean is providing the proof. Many transatlantic, commercial, and private aircraft use airspace around Montserrat, where the Soufriere Hills Volcano has been erupting since 1995.
Worldwide over the last 15 years, more than 80 airplanes have reported encountering volcanic ash along flight paths. Encounters cannot be avoided because onboard radar cannot detect fine-grained ash particlesâthose with a radius of 15 microns or less. In recent years volcanic cloud encounters are estimated to have caused hundreds of millions of dollars worth of damage and in a few cases have caused in-flight engine failure [Casadevall et al., 1996]
The Distance to the Coma Cluster from Surface Brightness Fluctuations
We report on the first determination of the distance to the Coma Cluster
based on surface brightness fluctuation (SBF) measurements obtained from Hubble
Space Telescope WFPC2 observations of the bright E0 galaxy NGC 4881 in the Coma
Cluster and ground-based observations of the standard E1 galaxy NGC 3379 in the
Leo-I group. Relative distances based on the I-band fluctuation magnitude,
I(SBF), are strongly dependent on metallicity and age of the stellar
population. However, the radial changes in the stellar populations of the two
giant ellipticals, NGC 3379 and NGC 4881, are well described by published Mg_2
gradients, and the ground-based measurements of I(SBF) at several radial points
in NGC 3379 are used to calibrate I(SBF) in terms of the Mg_2 index. The
distance to NGC 3379, assumed to be identical to the average SBF distance of
the Leo-I group, is combined with the new SBF measurements of NGC 4881 to
obtain a Coma Cluster distance of 102+-14 Mpc. Combining this distance with the
cosmic recession velocity of Coma (7186+-428 km/s), we find the Hubble constant
to be H_0 = 71+-11 km/s/Mpc.Comment: 12 pages, LaTex, includes aaspp4.sty and 3 eps figures. To appear in
ApJ Letter
Effects of retail employees' behaviours on customers' service evaluation
Purpose â The purpose of this paper is to test a conceptual model of the effects of customer and service orientation (SO) behaviours of individual retail employees on individual customersâ perceptions of service encounter quality (SEQ), service quality (SQ), value, satisfaction, and behavioural intentions (BI). Design/methodology/approach â The sample (n ÂŒ 271) was customers of a supermarket in central India, and they completed questionnaires following mall intercept. To test the hypotheses, structural equation modelling using LISREL 8.7 was employed. Findings â It was found that: service and customer orientation (CO) behaviours are positively related to SEQ and SQ; SEQ is positively related to SQ and customer satisfaction; SQ is positively related to value perceptions and customer satisfaction; and customer satisfaction is positively related to retail customersâ BI. However, value is not related to customer satisfaction. Research limitations/implications â More research is needed on customer perceptions of value in non-Western contexts and service evaluation frameworks in other cross-cultural contexts. Practical implications â Retail managers need to train or select retail personnel who are able to perform their roles in a service-oriented and customer-oriented way, and value does not appear to be as important to Indian retail customers as it is to Western retail customers. Originality/value â This paper extends current service evaluation frameworks by including SO and CO as antecedents, and it analyses an Indian retail context. Keywords India, Retailing, Customer satisfaction, Service levels, Employee behaviour
Material Characterization and Real-Time Wear Evaluation of Pistons and Cylinder Liners of the Tiger 131 Military Tank
Material characterisation and wear evaluation of the original and replacement pistons and cylinder-liners of Tiger 131 is reported. Original piston and cylinder-liner were operative in the Tigersâ engine during WWII. The replacement piston and cylinder-liner were used as substitutes and were obtained after failure in two hours of operation in the actual engine. Material characterisation revealed that the original piston was aluminium silicon hypereutectic alloy whereas the replacement piston was aluminium copper alloy with very low silicon content. Both original and replacement cylinder-liners consisted of mostly iron which is indicative of cast iron, a common material for this application. The replacement piston average surface roughness was found to be 9.09 ÎŒm while for replacement cylinder-liner it was 5.78 ÎŒm
The utility of pulse volume waveforms in the identification of lower limb arterial insufficiency
Background: The ankle brachial index is widely
used for non-invasive assessment of lower limb
arterial status, but has recognised limitations.
The most significant limitation involves arterial
calcification, which results in artefactually raised
occlusion pressures and uninformative ankle
brachial indices.
Hypothesis: Analysis of the pulse volume waveform is useful for identification of lower limb
arterial insufficiency in the presence of arterial
calcification.
Method: Individuals (n = 1101) registered at a
Welsh general practice were invited to undergo
cardiovascular risk assessment. The ankle brachial index was measured using an automated
device utilising volume plethysmography and the
traditional Doppler ultrasound method.
Results: Eight percent of participants (30/368)
had an ankle brachial index *1.3, suggesting
possible arterial calcification; consideration of
the pulse volume waveform in these cases identified possible mild peripheral arterial disease in
three cases (10%). Furthermore, in one case, the
ankle brachial indices were within the normal
range, but the pulse volume waveforms suggested a moderate degree of arterial insufficiency; this participant was subsequently diagnosed with bilateral superficial femoral artery
stenoses and treated accordingly.
Conclusion: Pulse volume waveforms can be
easily utilised as an adjunct to ankle brachial
index measurement to identify patients who may
benefit from further vascular assessment and
interventio
Primary accumulation in the Soviet transition
The Soviet background to the idea of primary socialist accumulation is presented. The mobilisation of labour power and of products into public sector investment from outside are shown to have been the two original forms of the concept. In Soviet primary accumulation the mobilisation of labour power was apparently more decisive than the mobilisation of products. The primary accumulation process had both intended and unintended results. Intended results included bringing most of the economy into the public sector, and industrialisation of the economy as a whole. Unintended results included substantial economic losses, and the proliferation of coercive institutions damaging to attainment of the ultimate goal - the building of a communist society
Real-time deterministic power flow control through dispatch of distributed energy resources
Integration of intermittent renewable resources and mass electrification of heat and transport into the existing electricity network, with limited network asset reinforcement requires incorporation of intelligence in form of active management of flexible resources within different sections of the distribution network. A hierarchical multi-level control framework is proposed for this purpose which incorporates the appropriate optimisation and control strategies at different levels. In particular a novel deterministic control algorithm for controlling power flows at the community cell level has been developed and presented in this paper. This algorithm incorporates robustness to communication and device failure and is easily expandable to an arbitrary number of devices. The simulation results presented in this paper show that the effectiveness of the proposed control technique depends on distributed energy resources flexibility and storage capacity
GPCRTree: online hierarchical classification of GPCR function
Background: G protein-coupled receptors (GPCRs) play important physiological roles transducing extracellular signals into intracellular responses. Approximately 50% of all marketed drugs target a GPCR. There remains considerable interest in effectively predicting the function of a GPCR from its primary sequence. Findings: Using techniques drawn from data mining and proteochemometrics, an alignment-free approach to GPCR classification has been devised. It uses a simple representation of a protein's physical properties. GPCRTree, a publicly-available internet server, implements an algorithm that classifies GPCRs at the class, sub-family and sub-subfamily level. Conclusion: A selective top-down classifier was developed which assigns sequences within a GPCR hierarchy. Compared to other publicly available GPCR prediction servers, GPCRTree is considerably more accurate at every level of classification. The server has been available online since March 2008 at URL: http://igrid-ext.cryst.bbk.ac.uk/gpcrtree
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