bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring operational safety in aviation
Authors: Rose Andrew 
Published: June 2006

PurposeThe paper seeks to outline the limitations and constraints in measuring operational safety in an aviation environment and provide an overview of the work being done at British Airways to overcome them.Design/methodology/approachThe paper looks at the limitations and problems of trying to measure safety and operational risk. These limitations are then discussed along with methodologies to overcome them. The paper then describes some of the methods being tried within British Airways to provide useful measures of risk whilst trying to avoid the problems identified previously.FindingsThe findings of the work are that there are potential ways to generate useful safety metrics from incident reporting data and that the best use of risk data is to focus attention within the organisation onto areas of risk that need to be addressed.Practical implicationsThe paper is based on practical work being undertaken at British Airways, and therefore, is demonstrated to be practical in an aviation environment.Originality/valueThe drive for operational efficiency in aviation means that aircraft operations are increasingly run against a backdrop of measures and targets. This in turn generates an increasing need and desire to include safety as a metric that can be tracked and monitored. This paper is focussed on meeting that desire and ensuring that any metrics developed avoid, as far as practical, the problems of measuring safety and using it to drive operational performance.
The operational efficiency of passenger aircraft
Authors: McLean Donald 
Published: June 2006

PurposeTo provide for the use of airlines and other civil aviation organizations a practical definition of operational efficiency and to show how it can be determined.Design/methodology/approachA brief account of air transport economics is used to demonstrate how bom load factors and aircraft utilization need to be considered in assessing operational efficiency. Then other efficiencies are treated briefly before an example is given of how the better of two fictitious aircraft can be chosen for a particular route. A second example involving the calculation of the operational efficiency achieved by an imaginary airline is also given to show that the typical value is lower than might be expected, particularly in view of the relatively high load factors involved.FindingsProvides performance values and economic figures which are typical of current airline operations.Practical implicationsUse of the proposed definition will allow the consistent assessment of the economic performance of airlines.Originality/valueAt present there is no definition of operational efficiency in general use although it is greatly needed by airlines. The definition proposed in this paper is practical and easy to use.
CIRSE: A solvation energy estimator compatible with flexible protein docking and design applications
Authors: Cerutti David S. , Jain Tushar , McCammon J. Andrew 
Published: June 2006

AbstractWe present the Coordinate Internal Representation of Solvation Energy (CIRSE) for computing the solvation energy of protein configurations in terms of pairwise interactions between their atoms with analytic derivatives. Currently, CIRSE is trained to a Poisson/surface‐area benchmark, but CIRSE is not meant to fit this benchmark exclusively. CIRSE predicts the overall solvation energy of protein structures from 331 NMR ensembles with 0.951 ± 0.047 correlation and predicts relative solvation energy changes between members of individual ensembles with an accuracy of 15.8 ± 9.6 kcal/mol. The energy of individual atoms in any of CIRSE's 17 types is predicted with at least 0.98 correlation. We apply the model in energy minimization, rotamer optimization, protein design, and protein docking applications. The CIRSE model shows some propensity to accumulate errors in energy minimization as well as rotamer optimization, but these errors are consistent enough that CIRSE correctly identifies the relative solvation energies of designed sequences as well as putative docked complexes. We analyze the errors accumulated by the CIRSE model during each type of simulation and suggest means of improving the model to be generally useful for all‐atom simulations.
Sequence of events in folding mechanism: Beyond the Gō model
Authors: Sutto Ludovico , Tiana Guido , Broglia Ricardo A. 
Published: June 2006

AbstractSimplified Gō models, where only native contacts interact favorably, have proven useful to characterize some aspects of the folding of small proteins. The success of these models is limited by the fact that all residues interact in the same way so that the folding features of a protein are determined only by the geometry of its native conformation. We present an extended version of a Cα‐based Gō model where different residues interact with different energies. The model is used to calculate the thermodynamics of three small proteins (Protein G, Src‐SH3, and CI2) and the effect of mutations (ΔΔGU‐N, ΔΔG‡‐N, ΔΔG‡‐U, and φ‐values) on the wild‐type sequence. The model allows us to investigate some of the most controversial areas in protein folding, such as its earliest stages and the nature of the unfolded state, subjects that have lately received particular attention.
A limited universe of membrane protein families and folds
Authors: Oberai Amit , Ihm Yungok , Kim Sanguk , Bowie James U. 
Published: June 2006

AbstractOne of the goals of structural genomics is to obtain a structural representative of almost every fold in nature. A recent estimate suggests that 70%–80% of soluble protein domains identified in the first 1000 genome sequences should be covered by about 25,000 structures—a reasonably achievable goal. As no current estimates exist for the number of membrane protein families, however, it is not possible to know whether family coverage is a realistic goal for membrane proteins. Here we find that virtually all polytopic helical membrane protein families are present in the already known sequences so we can make an estimate of the total number of families. We find that only ∼700 polytopic membrane protein families account for 80% of structured residues and ∼1700 cover 90% of structured residues. While apparently a finite and reachable goal, we estimate that it will likely take more than three decades to obtain the structures needed for 90% residue coverage, if current trends continue.
Structural studies of human alkaline phosphatase in complex with strontium: Implication for its secondary effect in bones
Authors: Llinas Paola , Masella Michel , Stigbrand Torgny , Ménez André , Stura Enrico A. , Le Du Marie Hélène 
Published: June 2006

AbstractStrontium is used in the treatment of osteoporosis as a ranelate compound, and in the treatment of painful scattered bone metastases as isotope. At very high doses and in certain conditions, it can lead to osteomalacia characterized by impairment of bone mineralization. The osteomalacia symptoms resemble those of hypophosphatasia, a rare inherited disorder associated with mutations in the gene encoding for tissue‐nonspecific alkaline phosphatase (TNAP). Human alkaline phosphatases have four metal binding sites—two for zinc, one for magnesium, and one for calcium ion—that can be substituted by strontium. Here we present the crystal structure of strontium‐substituted human placental alkaline phosphatase (PLAP), a related isozyme of TNAP, in which such replacement can have important physiological implications. The structure shows that strontium substitutes the calcium ion with concomitant modification of the metal coordination. The use of the flexible and polarizable force‐field TCPEp (topological and classical polarization effects for proteins) predicts that calcium or strontium has similar interaction energies at the calcium‐binding site of PLAP. Since calcium helps stabilize a large area that includes loops 210–228 and 250–297, its substitution by strontium could affect the stability of this region. Energy calculations suggest that only at high doses of strontium, comparable to those found for calcium, can strontium substitute for calcium. Since osteomalacia is observed after ingestion of high doses of strontium, alkaline phosphatase is likely to be one of the targets of strontium, and thus this enzyme might be involved in this disease.
Platelet‐dependent thrombography: a method for diagnostic laboratories
Authors: Dargaud Yesim , Luddington Roger , Baglin Trevor 
Published: June 2006

SummaryThe thrombin‐platelet feedback loop was examined at low concentration tissue factor using calibrated automated thrombography in combination with the elimination of contact factor activation by corn trypsin inhibitor. The results indicated that, when contact factor activation was eliminated, the thrombin‐platelet feedback loop was a major determinant of thrombin generating capacity and that platelets had a greater role in regulating the propagation of thrombin generation than its initiation. This method has potential application to the measurement of platelet‐dependent thrombin generation in clinical diagnostic laboratories and hence the investigation of patients with apparent hypo‐ or hypercoagulable phenotypes.
Self‐potential data interpretation using standard deviations of depths computed from moving‐average residual anomalies
Authors: Abdelrahman E.M. , Essa K.S. , Abo‐Ezz E.R. , Soliman K.S. 
Published: June 2006

ABSTRACTWe have developed a least‐squares minimization approach to determine simultaneously the shape (shape factor) and the depth of a buried structure from self‐potential (SP) data. The method is based on computing the standard deviation of the depths determined from all moving‐average residual anomalies obtained from SP data, using filters of successive window lengths for each shape factor. The standard deviation may generally be considered a criterion for determining the correct depth and shape factor of the buried structure. When the correct shape factor is used, the standard deviation of the depths is less than the standard deviations computed using incorrect shape factors. This method is applied to synthetic data with and without random errors, complicated regionals and interference from neighbouring sources, and is tested on a known field example from Turkey. In all cases, the shape and depth solutions obtained are in a good agreement with the actual values.
Linear demultiple solution based on the concept of bottom‐multiple‐generator (BMG) approxiamtion: some new results
Authors: Oladeinde Abiola O. , Ikelle Luc T. 
Published: June 2006

ABSTRACTRecent advances in the demultiple technique have shown that a multidimensional convolution of a portion of data containing only primaries with the whole data (containing both primaries and multiples) can allow us to predict and attenuate all orders of free‐surface multiples that are relevant for practical purposes. One way of constructing the portion of the data containing only primaries is by muting the actual data just above the first free‐surface multiple to arrive. The location of the mute is generally known as the bottom‐multiple‐generator (BMG) reflector; the portion of the data containing only primaries required for constructing the free‐surface multiples is located above the BMG. The outstanding question about this method is how effective can the technique be when the BMG cuts through several seismic events, as is the case in long‐offset data or in very complex shallow geology. We present new results which demonstrate the fact that the BMG location may cut through several seismic events without affecting the accuracy or the cost of demultiple.
Electromagnetic fields in a non‐uniform steel‐cased borehole
Authors: Kim Hee Joon , Lee Ki Ha 
Published: June 2006

ABSTRACTSince most oil wells are cased in steel, electromagnetic (EM) signals undergo severe attenuation as they diffuse across the casing. This paper examines an effect of non‐uniform casing properties on EM fields measured in a steel‐cased well embedded in a layered formation. We use a finite‐element method for computing secondary azimuthal electric fields in a cylindrically symmetric model, and analytically obtain primary fields for a homogeneous casing in a homogeneous whole space. Although steel casing largely masks EM signals induced into a layered formation, the induced signal is more pronounced in phase than in amplitude. The effect of casing non‐uniformity is quite large in measured fields but is highly localized. When electrical conductivity varies rapidly in the casing wall, the resulting EM fields also vary rapidly. A cross‐correlation function of these variations has strong peaks at two points, the interval between them being equal to the source–receiver distance. The high‐frequency coherent noise event caused by the non‐uniform casing can be greatly suppressed by low‐pass filtering to enhance EM signals indicating formation conductivity.
Theory and seismic applications of the eigenimage discrete wavelet transform
Authors: Droujinine Alexander 
Published: June 2006

ABSTRACTDiscrete wavelet transforms are useful in a number of signal processing applications. To improve the scale resolution, a joint function of time, scale and eigenvalue that describes the energy density or intensity of a signal simultaneously in the wavelet and eigenimage domains is constructed. A hybrid method, which decomposes eigenimages in the wavelet domain, is developed and tested on field data with a variety of noise types. Several illustrative examples examine the ability of wavelet transforms to resolve features at several scales. Successful applications to time‐lapse seismic reservoir monitoring are presented. In reservoir monitoring, the scale‐dependent properties of the eigenstructure of the 4D data covariance matrix enable us to extract the low‐frequency time‐lapse signal that is the result of internal diffusive losses caused by fluid flow.
Theoretical development of the differential scattering decomposition for the 3D resistivity experiment
Authors: Oldenborger Greg A. , Routh Partha S. 
Published: June 2006

ABSTRACTIn any numerical solution of the DC resistivity experiment, care must be taken to deal with strong heterogeneity of electrical conductivity. In order to examine the importance of conductivity contrasts, we develop a scattering decomposition of the DC resistivity equation in the sparse differential domain as opposed to the traditional dense integral formulation of scattering‐type equations. We remove the singularity in the differential scattered series via separation of primary and secondary conductivity, thereby avoiding the need to address the singularity in a Green's function. The differential scattering series is observed to diverge for large conductivity contrasts and to converge for small contrasts. We derive a convergence criterion, in terms of matrix norms for the weak‐form finite‐volume equations, that accounts for both the magnitude and distribution of heterogeneity of electrical conductivity. We demonstrate the relationship between the differential scattering series and the Fréchet derivative of the electrical potential with respect to electrical conductivity, and we show how the development may be applied to the inverse problem. For linearization associated with the Fréchet derivative to be valid, the perturbation in electrical conductivity must be small as defined by the convergence of the scattered series. The differential scattering formulation also provides an efficient tool for gaining insight into charge accumulation across contrasts in electrical conductivity, and we present a derivation that equates accumulated surface charge density to the source of scattered potential.
The human renal lymphatics under normal and pathological conditions
Authors: Ishikawa Y , Akasaka Y , Kiguchi H , Akishima‐Fukasawa Y , Hasegawa T , Ito K , Kimura‐Matsumoto M , Ishiguro S , Morita H , Sato S , Soh S , Ishii T 
Published: June 2006

Aims:  The renal lymphatics have not been fully documented in humans. The aim of this study was to clarify the morphology of the human renal lymphatic system under normal and pathological conditions by immunohistochemistry using anti‐D2‐40 antibody.Methods and results:  Normal and pathological renal tissues obtained at autopsy as well as nephrectomy specimens with renal cell carcinoma (RCC) were used. Thin sections were immunostained with antibodies against D2‐40 and CD31. In normal kidney, D2‐40+ lymphatics were abundant in the interstitium around the interlobar and arcuate arteries/veins but sporadic in those around the glomeruli or between the tubules in the cortex. A few lymphatics contained erythrocytes in their lumina. Lymphatics were seldom present in the medulla. In RCC cases, lymphatics were evident at the tumour margin, whereas CD31+ capillaries were abundant throughout the tumour and lymphatics were increased in the fibrous interstitium around the tumour. Lymphatic invasion by RCC cells was also detectable. D2‐40+ lymphatics were evident in other pathological conditions and end‐stage kidney had a denser lymphatic distribution than normal kidney.Conclusions:  Lymphatics are abundant around the arteries/veins and are also present in the renal cortex and medulla. D2‐40 immunostaining is helpful for investigating the pathophysiological role of renal lymphatics.
Low‐grade fibrosarcoma—report on 39 not otherwise specified cases and comparison with defined low‐grade fibrosarcoma types
Authors: Hansen T , Katenkamp K , Brodhun M , Katenkamp D 
Published: June 2006

Aims:  Low‐grade fibrosarcomas are tumours that mainly affect the extremities and trunk of adults of either sex. Among these, low‐grade fibromyxoid sarcoma (FMS), hyalinizing spindle cell tumour with giant collagen rosettes (HST) and sclerosing epithelioid fibrosarcoma (SEF) are well‐established entities. In this study, our aim was to describe a group of low‐grade fibrosarcomatous tumours, which could not be encompassed by these entities. These low‐grade fibrosarcomas, not otherwise specified (FNOS) were provisionally designated as ‘fibrosarcoma, low‐grade fibroblastic type’.Methods and results:  In the soft tissue tumour registry we found 39 FNOS (46%), 31 FMS (36%), 11 SEF (13%) and four HST (5%). FNOS occurred in older patients than FMS (mean age 56.3 years versus 33.7 years). They mainly showed fibrous features, but myxoid areas could also be seen. While cells tended to be loosely arranged in the myxoid areas, densely packed sheets with a storiform pattern, fascicular arrangements or regions without a defined growth pattern were observed in the fibrous areas. However, neither whirling nor swirling patterns were found. Arcade‐like vessels were not visible; pseudolipoblasts did not occur. FNOS exhibited increased atypia and mitotic count compared with the other sarcomas studied [FNOS, mean value 4.6 mitoses/10 high‐power field (HPF); FMS, 0.7/10 HPF). Follow‐up data were available in 21 FNOS patients. In seven cases (33.3%), local recurrences were reported. Three patients (14.3%) developed metastases and all of them died of tumour.Conclusions:  The term ‘fibrosarcoma, low‐grade fibroblastic type’ should be used as a diagnosis of exclusion. Further studies should elucidate whether it represents a distinct fibrosarcoma type.
Indigenous children and receipt of hospital dental care in Australia
Authors: JAMIESON L. M. , ROBERTS‐THOMSON K. F. 
Published: June 2006

Summary.  Objective.  The aim of this study was to investigate dental procedures received under hospital general anaesthetic by indigenous and non‐indigenous Australian children in 2002–2003.Methods.  Separation data from 1297 public and private hospitals were obtained from the Australian Institute of Health and Welfare National Hospital Morbidity Database for 2002–2003. The dependant variable was the admission rate of children receiving four categories of dental care (i.e. extraction, pulpal, restoration or other). The explanatory variables included sex, age group, indigenous status and location (i.e. major city, regional or remote). Rates were calculated using estimated resident population counts.Results.  The sample included 24 874 children aged from 2 to 14 years. Some 4·3% were indigenous (n = 1062). Admission rates for indigenous and non‐indigenous children were similar, with indigenous males having 1·2 times the admission rate of indigenous females (P < 0·05). Indigenous children aged < 5 years had 1·4 times the admission rate of similarly aged non‐indigenous children (P < 0·001) and 5·0 times the admission rate of 10–14‐year‐old indigenous children (P < 0·001). Remote‐living indigenous children had 1·5 times the admission rate of their counterparts in major cities or regional areas (P < 0·001), and 1·4 times the admission rate of remote‐living non‐indigenous children (P < 0·01). The extraction rate of indigenous males was 1·3 times that of non‐indigenous males (P < 0·01), and 1·2 times that of indigenous females (P < 0·05). Pre‐school indigenous children had 2·2 times the extraction rate of similarly aged non‐indigenous children (P < 0·001), and 5·3 times that of indigenous 10–14‐year‐olds (P < 0·001). The extraction rate of remotely located indigenous children was 1·5 times that of indigenous children in major cities (P < 0·01), and 1·8 times that of remote‐living non‐indigenous children (P < 0·001).Conclusions.  In certain strata – particularly males, the very young and those in remote locations – indigenous children experienced higher rates of extractions than non‐indigenous children when undergoing care in a hospital dental general anaesthetic setting.
A qualitative look at parents' experience of their child's dental general anaesthesia
Authors: AMIN M. S. , HARRISON R. L. , WEINSTEIN P. 
Published: June 2006

Summary.  Objectives.  Caries relapse after treatment of early childhood caries (ECC) under general anaesthesia (GA) has been frequently reported. This research used a qualitative method of inquiry to explore parents’ experience of their child's treatment under GA, and their perception of the impact of this treatment on their child.Methods.  The participants were parents whose children had recently undergone dental rehabilitation under GA. Data was collected by semistructured, open‐ended interviews scheduled at the postoperative appointment. Interviews were audio‐taped, transcribed, checked and coded into a qualitative computer software program for analysis. Data collection and analysis were done simultaneously, and the interview guide was modified based on responses.Results.  Parents were troubled that their child needed a GA and appeared aware of the complications. While some parents felt ‘guilty’ and struggled to accept this mode of treatment for their child, others felt ‘blameless’, and were convinced that the GA was ‘preferable’ for their child and superior to conventional treatment. Nonetheless, all parents reported some levels of anxiety during the GA; they expressed their emotions with ‘fear’, ‘worry’ and ‘concern’. After the GA, improvement was reported by most parents in their child's amount of dental pain, sleeping pattern, eating habits and acceptance of parental toothbrushing. The most common changes in their child's behaviour mentioned by parents were increased toothbrushing and decreased consumption of sugary foods. Several children who had had primary teeth extracted were distressed as a result of this ‘loss’.Conclusion.  The general anaesthetic experience was troubling in a variety of ways for both parents and children. However, an ‘early’ and positive outcome of the GA was a reported improvement in dental health practices. Parents were more positive about maintaining the health of primary teeth and now knew how to take care of their child's teeth. Future exploration is required to reveal if and how the GA experience will affect long‐term preventive behaviours.