bluuebunny/crossref_metadata_2025_split huggingface dataset:
Results of the United Kingdoms first pilot study for nonmedical endoscopy practitioners
Authors: Gardiner A. B. 
Published: May 2008

AbstractObjective  Spencer and Ready published the first description of nonmedically qualified endoscopists in 1977 [Dis Colon Rectum 1977; 20: 94]. Since then there has been an explosion of interest in this concept. Duthie et al. [Gut 1998; 43: 711] first described Nurse Endoscopy (NE) in the UK in 1998. In recent years, endoscopy services in England have been subject to review as a consequence of perceived inadequacies in service provision and delivery.Method  Increasing pressure on endoscopic services led the Modernisation Agency to commission a pilot study evaluating nontraditional individuals to practice flexible sigmoidoscopy (FS). A science graduate, basic grade nurse and nonclinical member of staff were successfully trained. As a result, a second pilot scheme was introduced, whereby nine nonmedically qualified individuals received education and training in FS. A curriculum was designed, developed and implemented to create an endoscopic practitioner (EP) who was both safe and competent to undertake FS. The student backgrounds included administration, health‐care assistants, phlebotomist, junior doctor assistant and clinical physiologist.Results  In the context of academic achievement, prescribed learning outcomes were achieved at a rate of 93% (101 from 108) of success in first attempt at assessment. In terms of practical achievement, each student demonstrated competency in FS.Conclusion  The curriculum designed provides a suitable framework to develop individuals with the necessary knowledge, skills and attitudes required for safe, competent practice within FS. This indicates that the curriculum provides a broad range of learning, teaching and assessment strategies befitting to a range of individuals.
Familial colorectal cancer: a concept revisited
Authors: Martellucci J. , Civitelli S. , Dhamo A. , Tanzini G. 
Published: May 2008

AbstractObjective  The family history of patients with colorectal cancer (CRC) shows an increased risk of disease although evident inherited syndromes are demonstrable in only a small percentage of patients. The purpose of this study was to identify factors that might suggest an inherited component in the transmission of CRC.Method  The study monitored 880 consecutive patients between 1980 and 2005 treated for CRC.Results  Familial adenomatous polyposis (FAP) was found in only one patient, and a classical mutation of hereditary nonpolyposis colon cancer was found in only two patients. The risk assessment was possible mainly because of factors such as early onset CRC, the presence of multiple primary tumours and a high risk family history. Considering these 36 more patients were suspected to be high risk and referred for further genetic testing. At least one first‐degree relative with CRC was reported in 140 patients. In 49 patients, CRC was diagnosed before 50 years of age. Multiple primary tumours, colonic or extra colonic, synchronous or metachronous were found in 136 patients.Conclusion  Our study suggests that if only patients with identified mutations are taken into consideration, then the percentage of evident hereditary colon cancer is very low, but this percentage quickly increases if we make marginal adjustments to the identifying criteria. It seems that it is the physician’s clinical suspicion, more than the fulfilment of rigid criteria, which plays a fundamental role in the timely identification and a subsequent focused treatment of patients with hereditary CRC.
The effect of 4% icodextrin solution on adhesiolysis surgery time at the Hartmann’s reversal: a pilot, multicentre, randomized control trial vs lactated Ringer’s solution
Authors: Kössi J. , Grönlund S. , Uotila‐Nieminen M. , Crowe A. , Knight A. , Keränen U. 
Published: May 2008

AbstractObjective  A pilot randomized controlled clinical multicentre trail was established to compare intraperitoneal 4% icodextrin (ID) solution with lactated Ringer’s solution (LRS) on adhesion formation after Hartmann’s procedure. The adhesiolysis surgery time during Hartman’s reversal was used as a marker of the severity of adhesions.Method  Patients scheduled for Hartmann’s resection were randomized at surgery to either of the two study solutions used as an irrigant during the operation and instilled (1000 ml) at the end of surgery. During the reversal procedure, the time for small bowel adhesiolysis was recorded.Results  On completion of 17 eligible patients, an interim analysis was performed. There were no complications following the use of 4% ID solution. The mean (SD) total adhesiolysis times in patients treated with 4% ID solution and LRS were 30.8 (18.0) min and 47.6 (45.7) min, respectively. The mean reduction of 16.8 min, although greater than expected, was not statistically significant (P = 0.33) because of the large variance in adhesiolysis times. Further statistical analysis showed that to achieve significance for the observed differences and variance, a minimum of 240 patients in each group would be required.Conclusion  Icodextrin treatment resulted in a decreasing trend in adhesiolysis time. The use of 4% ID solution in peritonitis patients seemed to be safe. Because of larger than expected variations in adhesiolysis times, this pilot study was underpowered to meet the study end‐point and further statistical modelling estimated that significance cannot be reached within a reasonable time scale. Other models should be used to evaluate the efficacy of anti‐adhesive agents.
Rhomboid excision and Limberg flap for managing pilonidal sinus: long‐term results in 411 patients
Authors: Akin M. , Gokbayir H. , Kilic K. , Topgul K. , Ozdemir E. , Ferahkose Z. 
Published: May 2008

AbstractObjective  To investigate the results of rhomboid excision and the Limberg flap procedure to treat pilonidal sinus disease.Method  The records of 411 patients with pilonidal sinus disease, who underwent rhomboid excision and Limberg flap procedure, were analysed. All sinus tracks were resected en bloc, and a Limberg flap was prepared from left or right gluteal region. A suction drain was routinely used.Results  The mean follow‐up period was 109.2 ± 4.5 months (range: 12–183 months). Recurrence occurred in 12 (2.91%) patients who were all male. In 42 (10.21%) patients, anaesthesia or hypoaesthesia of the upper portion of the flap occurred; this was temporary in 25 patients. Twelve (2.91%) patients developed a seroma and 15 (3.64%) a wound infection. The average hospital stay was 3.2 days (range: 1–10 days), and the average time of return to work was 12.4 days (range: 7–18 days). The average time to walk without pain was 13.4 days (range: 10–28 days) and the average time to sitting on the toilet without pain was 16.1 days (range: 12–28 days).Conclusion  The Limberg flap procedure is effective and has a low complication rate, short time for returning to normal activity and short hospitalization.
Semantic Interoperability through the Definition of Conceptual Model Transformations
Authors: Staub Peter , Gnägi Hans Rudolf , Morf Andreas 
Published: May 2008

AbstractThe integration of distributed geospatial data is a great issue in GI Science. Hereby, the collection of data from different systems and different structures as well as across country borders is a problem. We explain a model‐based four‐step approach to conceptual data modelling. Within this approach, we introduce a methodology to map data models on the conceptual level without touching data formats. First, we developed a conceptual mapping language called “UMLT” which is the core of our approach. Furthermore, we integrated UMLT into the Model‐Driven Architecture where a conceptual model mapping is referred to as a platform independent model mapping. Finally, the data format transformation is deduced from the model mapping automatically. This represents the implementation mapping from a platform independent model to a platform specific model. Together with transformation operations for attribute mapping, this approach is a means for effective and enhanced semantic interoperability.
A GIS‐Based Tool for Spatial and Distributed Hydrological Modelling: CLASS Spatial Analyst
Authors: Teng Jin , Vaze Jai , Tuteja Narendra K , Gallant John C 
Published: May 2008

AbstractCLASS Spatial Analyst is a GIS tool which can be used to support spatially distributed hydrological modelling. The tool generates a number of spatial layers that can be used for many practical applications. These include climate zoning, multi‐resolution DEMs, Compound Topographic Index (CTI) (also referred to as Topographic Wetness Index, TWI), lateral multiple flow paths, accumulation and dispersion of water and solutes from hazard areas, estimation of soil depth, soil material/horizon distribution and soil moisture storage capacity in different parts of the landscape. Although each of these tasks can be undertaken separately using spatial software packages such as ArcGIS, GRASS, TIME, and MapInfo, this tool puts together all these tasks into a single application which provides the user with an option of undertaking some or all of them within this application. The technology used in this tool is supported by various peer‐reviewed publications (e.g. Tarboton 1997, Gallant and Dowling 2003).
A GIS‐Based Model to Determine Site Suitability of Emergency Evacuation Shelters
Authors: Kar Bandana , Hodgson Michael E 
Published: May 2008

AbstractIn recent years, the increase in the number of hurricanes and other costal hazards in the US pose a tremendous threat to the residents of coastal states. According to the National Hurricane Center, Florida is the most vulnerable coastal state to hurricanes. Mitigation policies have been formulated to reduce mortality and provide emergency services by evacuating people from the hazard zone. Many of these evacuees, particularly the elderly or lower income populations, rely on evacuation shelters for temporary housing. Because of the cost and limited use, evacuation shelters are almost exclusively dual use shelters where the primary purpose of the facility is for some other public function (e.g. school, hospital, etc.). In 2000, the estimated shortage of public shelter spaces in Florida was about 1.5 million. The purpose of this study was to rank the existing and candidate shelters (schools, colleges, churches and community centers) available in the state based on their site suitability. The research questions examined in this study include: (1) How many candidate shelters are located in physically suitable areas (e.g. not in a flood prone area, not near hazardous facilities, etc.)?; (2) How many existing shelters are located in physically unsuitable areas, but in socially suitable areas (situated in areas with demand)?; (3) How many alternative existing and/or candidate shelters with high/very high physical suitability are located near physically unsuitable existing shelters and thus, may be better choices for a shelter?; and (4) How many existing shelters located in physically unsuitable areas are not near alternative existing and/or candidate shelters? A Geographic Information System‐based suitability model integrating Weighted Linear Combination (WLC) with a Pass/Fail screening technique was implemented for the 17 counties of Southern Florida. It was found that 48% of the existing shelters are located in physically unsuitable areas. Out of all the candidate shelters, 57% are located in physically unsuitable areas. For 15 of the existing shelters in unsuitable locations, no alternative candidate or existing shelter with medium to high physical suitability exists within 10 miles (16.1 km).
Using Topological Relationships to Inform a Data Integration Process
Authors: Hope Sue , Kealy Allison 
Published: May 2008

AbstractWhen spatial datasets are overlaid, corresponding features do not always coincide. This may be a result of the datasets having differing quality characteristics, being captured at different scales or perhaps being in different projections or datums. Data integration methods have been developed to bring such datasets into alignment. Although these methods attempt to maintain topological relationships within each dataset, spatial relationships between features in different datasets are generally not considered. The preservation of inter‐dataset topology is a research area of considerable current interest. This research addresses the preservation of topology within a data integration process. It describes the functional models established to represent a number of spatial relationships as observation equations. These are used to provide additional information concerning the relative positions of features. Since many topological relationships are best modelled as inequalities, an algorithm is developed to accommodate such relationships. The method, based on least squares with inequalities (LSI), is tested on simulated and real datasets. Results are presented to illustrate the optimal positioning solutions determined using all of the available information. In addition, updated quality parameters are provided at the level of the individual coordinate, enabling communication of local variation in the resultant quality of the integrated datasets.
The Development of the Chagas’ Online Data Entry System (CODES‐GIS)
Authors: Blackburn Jason K , Curtis Andrew , Mujica Frances Currin , Jones Farrell , Dorn Patricia , Coates Rosamond 
Published: May 2008

AbstractThis article describes a web‐based data entry and GIS‐driven mapping system designed for an ethnographic and entomological survey of Chagas’ disease, an emerging zoonotic disease, and Triatoma dimidiata, a primary vector, in the Los Tuxtlas region of Veracruz, Mexico. To better understand this disease in the region, a collaborative, multi‐disciplinary study was initiated to conduct a spatial investigation of T. dimidiata and a community‐by‐community survey of local perceptions of the disease. In order to facilitate such a collaborative effort the CODES‐GIS was developed. This system allows for (near) real‐time mapping, analyses, disease reporting, and results sharing. CODES‐GIS provides a framework for a research team working in a remote area with limited technology, software, or GIS expertise to benefit from (near) real‐time spatial analyses performed at collaborating institutions. The system is bi‐directional, where field personnel can upload data to the system for field‐based map production. Likewise, laboratory personnel can upload diagnostics data for viewing by field personnel. In this way, the system provides a virtual link between the field and the laboratory to increase the speed at which results are returned to the local community. The CODES‐GIS is described along with a selection of study results.
INVERSE AUTOCOVARIANCES AND A MEASURE OF LINEAR DETERMINISM FOR A STATIONARY PROCESS
Authors: Battaglia Francesco 
Published: May 2008

Abstract. The inverse autocorrelations and autocovariances of a stationary stochastic process are generally used in the identification of ARMA models and linear systems, but they are also useful for studying linear relations inside the process as a whole.Using inverse autocovariances, for any stationary process an ‘inverse process’ may be defined which may be considered a minimum variance linear filter, and turns out to be the best linear two‐sided interpolator for one unknown value.Basing on these results an index of linear determinism is introduced to measure to what degree a stationary process satisfies a linear deterministic constraint. The behaviour of the index for ARMA processes is finally examined.
A UNIFIED APPROACH TO ARMA MODEL IDENTIFICATION AND PRELIMINARY ESTIMATION
Authors: Piccolo D. , Wilson G. Tunnicliffe 
Published: May 2008

Abstract.This paper reviews several different methods for identifying the orders of autoregressive‐moving average models for time series data. The case is made that these have a common basis, and that a unified approach may be found in the analysis of a matrix G, defined to be the covariance matrix of forecast values.The estimation of this matrix is considered, emphasis being placed on the use of high order autoregression to approximate the predictor coefficients. Statistical procedures are proposed for analysing G, and identifying the model orders.A simulation example and three sets of real data are used to illustrate the procedure, which appears to be a very useful tool for order identification and preliminary model estimation.
WALSH‐FOURIER ANALYSIS OF DISCRETE‐VALUED TIME SERIES
Authors: Stoffer David S. 
Published: May 2008

Abstract.An approach to the analyses of discrete‐valued time series is discussed. The analyses are accomplished in the spectral domain using the Walsh‐Fourier transform which is based on Walsh functions. This approach will enable an investigator of discrete systems to analyse the data in terms of square waveforms and sequency rather than sine waves and frequency.We develop a general signal‐plus‐noise type model for discrete‐valued time series in which Walsh‐Fourier spectral analysis is of interest. We consider the problems of detecting whether a common signal exists in repeated measures on discrete‐valued time series and in discrete‐valued processes collected in an experimental design. We show that these models may depend on unknown regression parameters and we develop consistent estimates of these parameters based on the finite Walsh‐Fourier transform. Applications to certain Markov models are given; however, the methods presented also apply to non‐Markov cases.
ON THE THIRD‐ORDER MOMENT STRUCTURE AND BISPECTRAL ANALYSIS OF SOME BILINEAR TIME SERIES
Authors: Gabr M. M. 
Published: May 2008

AbstractFor the bilinear time series modelXt=βXt‐ket‐t+et, k > l, k = l andk<lformulae for the third‐order theoretical moments and an expression for the bispectral density function are obtained. These results can be used to distinguish between bilinear models and white noise and, in general, linear models. Furthermore, they give an indication of the type combination (k, l) in the above model. The modulus of the bispectral density function of the above bilinear time series model for different combinations of (k, l) and values ofβare computed and the properties are studied.
TIME DELAY ESTIMATION
Authors: Hannan E. J. , Thomson P. J. 
Published: May 2008

AbstractThe problem considered is that of estimating the delays that arise when a waveform propagates across an array. Problems that arise in previous estimation techniques when the signal‐to‐noise ratio is low are reduced by introducing an improved weighting of frequencies into the formulae and by using finite parameter models to estimate this weight function. The virtues of the various procedures are checked by simulations.
PREDICTION ERROR OF MULTIVARIATE TIME SERIES WITH MIS‐SPECIFIED MODELS
Authors: Lewis Richard A. , Reinsel Gregory C. 
Published: May 2008

AbstractWe consider the situation in which an incorrectly specified autoregressive moving‐average model is used to predict future values of a stationary multivariate time series. The use of an incorrect model for prediction results in an increase in mean‐square prediction error over that of the optimal predictor, and an expression for this increase is first given for fixed values of the parameters in the incorrect model. For the case in which the incorrect model is an autoregression, we also take into account parameter estimation error by first deriving the asymptotic distribution and limiting moment properties of the least‐squares estimator of the parameters in the mis‐specified model. An asymptotic approximation to the increase in mean‐square prediction error is then obtained. Numerical examples are provided to demonstrate the accuracy of the asymptotic approximation in finite samples. Our results are consistent with those obtained in the univariate case, indicating that fitted autoregressions of high order can yield substantially sub‐optimal forecasts.
AN EXACT TEST FOR A STOCHASTIC COEFFICIENT IN A TIME SERIES REGRESSION MODEL
Authors: Shively Thomas S. 
Published: May 2008

AbstractAn exact small‐sample test is developed for testing the hypothesis that a regression coefficient is constant against the alternative that it is generated by a random walk process. The test is mean‐ and scale‐invariant and approximates the most powerful invariant test against any specific alternative. It thus outperforms tests previously given in the literature. Computationally efficient algorithms are given to compute the test statistic and its distribution using a modified version of the Kalman filter.
ESTIMATION FOR NON‐LINEAR TIME SERIES MODELS USING ESTIMATING EQUATIONS
Authors: Thavaneswaran A. , Abraham B. 
Published: May 2008

AbstractGodambe's (1985) theorem on optimal estimating equations for stochastic processes is applied to non‐linear time series estimation problems. Examples are considered from the usual classes of non‐linear time series models. A recursive estimation procedure based on optimal estimating equations is provided. It is also shown that pre‐filtered estimates can be used to obtain the optimal estimate from a non‐linear state‐space model.
STATIONARITY AND CENTRAL LIMIT THEOREM ASSOCIATED WITH BILINEAR TIME SERIES MODELS
Authors: Chanda Kamal C. 
Published: May 2008

Abstract. Consider the general bilinear times series model
image
where {Xt; t= 0, L1, …} is a p‐variate process, C(p x (s+ 1)), A(p x p). Bt(p x p) (1 ≤j≤q) are arbitrary matrices of constants, εT=[εt,…εt‐q+1] and {εt; t=0, ±1, …} is a strictly stationary ergodic sequence of random variables. We investigate a set of minimal regularity conditions (on C, A, Bj and {εt}) under which we can establish the existence and causality of Xt and the asymptotic normality of the sample mean derived from {Xt}.
KERNEL REGRESSION SMOOTHING OF TIME SERIES
Authors: Härdle Wolfgang , Vieu Philippe 
Published: May 2008

Abstract. A class of non‐parametric regression smoothers for times series is defined by the kernel method. The kernel approach allows flexible modelling of a time series without reference to a specific parametric class. The technique is applicable to detection of non‐linear dependences in time series and to prediction in smooth regression models with serially correlated observations.In practice these estimators are to be tuned by a smoothing parameter. A data‐driven selector for this smoothing parameter is presented that asymptotically minimizes a squared error measure. We prove asymptotic optimality of this selector. We illustrate the technique with a simulated example and by constructing a smooth prediction curve for the variation of gold prices. In both cases the non‐parametric method proves to be useful in uncovering non‐linear structure.
TESTING FOR WHITE NOISE AGAINST MULTIMODAL SPECTRAL ALTERNATIVES
Authors: Reschenhofer E. , Bomze I. M. 
Published: May 2008

Abstract.The test for white noise proposed by Reschenhofer (Biometrika76 (1989) 629–32) is adaptive in that the form of its test statistic depends on the data. It proceeds (i) by using the real part of the finite Fourier transform of the data for the selection of the form of the test statistic and (ii) by applying the selected test statistic to the imaginary part.In this paper it is shown that independently of using information contained in the real part to construct a test statistic for the imaginary part, information contained in the imaginary part can be used to construct a test statistic for the real part. Because of the independence of these tests, they can easily be combined.Then a further test is proposed which again is adaptive but where both the real and imaginary parts contribute simultaneously to a single test statistic.