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Objectives We evaluated the feasibility of implementing a Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) program at our urban level 1 trauma center and evaluated early outcomes.Design A multidisciplinary committee including physicians (trauma surgery, emergency medicine, vascular surgery, and interventional radiology) and nurses created clinical practice guidelines for the placement of REBOA at our institution. All trauma surgeons and critical care board certified emergency medicine physicians were trained in placement and nurses received management training. A formal review process was implemented to identify areas for improvement. Finally, we instituted refresher training to maintain REBOA competency. Trauma patients with noncompressible torso hemorrhage from blunt or penetrating injuries who were partial or nonresponders to blood product resuscitation were included. Pregnant patients, children, or patients with significant hemothorax or suspected aortic or cardiac injury were excluded.Results Over seven months, eight catheters were successfully placed, all on the first attempt, including six in Zone 3 and two in Zone 1. All Zone 3 catheters were placed for pelvic fracture-related bleeding which were subsequently embolized. The Zone 1 catheters were placed immediately preoperatively for intraabdominal bleeding. Upon committee review, one critique was made regarding zone selection. One patient developed an arteriovenous fistula after placement which resolved without intervention. There were no other complications and all patients survived to discharge.Conclusions An REBOA program is feasible and safe following a comprehensive multidisciplinary effort. The efforts described here can be utilized by similar trauma programs for adaptation of this endovascular approach to bleeding control.

In this paper, a neural-network based driver advisory train cruise control system is considered. The controller assists the train driver with advisory signals by considering train and driver’s actual state information (attention and fatigue) measured by dedicated sensors. Considering delays in sensor measurements, this paper aims to assess closed-loop stability of driver-in-the-loop advisory train cruise control. For this purpose, the driver model is considered as a time-varying system, the train model includes rolling and aerodynamic resistance forces and the advisory control is considered to be a sampled-data based three layer multi-layer perceptron. Further, the aperiodic measurement problem is approached as stability analysis of time-varying delayed system. Based on recent developments on the design of augemented Lyapunov Krasovskii Functional (LKF) using Bessel-Legendre inequality for time-varying delays, sufficiency conditions for the existence of L2stability of the driver-train system in terms of solvable Linear Matrix Inequalities are provided. Further a case study is presented to illustrate the effectiveness of the proposed method.

Earthquake prediction has been a challenging but an unsuccessful task until now and has not provided reliable forecasting mechanism. Developments of prediction tools are limited and there is huge gap between the known post-shock data and unknown pre shock data. In the present case, an attempt is being made to develop a breakthrough for predicting earthquakes through its response on groundwater level in the Bhuj/Kachchh region, Gujarat, India. High frequency groundwater level data from 5 monitoring stations recorded the pre, co-seismic and post seismic events of the 2001 Bhuj earthquake. Pre-seismic signatures in form of sharp decline 85 days and in another station 21 days prior to the earthquake event. Although the observations are based on limited data, but if the density of the monitoring wells are increased in the seismic/active fault zones, the groundwater level have the potential to reflect the tectonically accumulated stresses and help in understanding the earthquake mechanism.

Ethionamide is part of a group of drugs used in the treatment of drug resistant TB. With the advent of increasing drug resistance in pulmonary TB cases, use of Ethionamide, a second line anti tubercular drug is increasing. Vision changes are rare with ethionamide. Cyanopsia i.e., bluish tinted vision of surroundings with ethionamide is not known in literature. Here, we report a case of DRTB patient who developed cyanopsia soon after introducing ethionamide. Although reversible, ethionamide may sometimes need withdrawal because of significant distress caused to patient.

Linezolid was approved for clinical use for methicillin resistant Staphylococcus aureusand vancomycin-resistant Enterococci. Additionally it is used in the management of drug resistant tuberculosis. It is well-tolerated however bone marrow suppression and neuropathies may occur in patients taking this antibiotic for more than 2 weeks. Black discoloration and black hairy tongue (BHT) due to linezolid is rarely reported. We report two cases of BHT.

The aim of the present study was to study microscopic colitis (MC) in children with special reference to its role in chronic diarrhea and changes in mucosal biopsies.

The aim of the present study was to study microscopic colitis (MC) in children with special reference to its role in chronic diarrhea and changes in mucosal biopsies. A total of 100 consecutive children ages 3 to 12 years, with nonbloody diarrhea (passage of =3 loose stools per day) of >12 weeks' duration were screened and 26 were enrolled in the study in which no specific etiology could be found and colonoscopy did not reveal any mucosal abnormality. Colonic biopsies were evaluated for the presence of lymphocytic colitis or collagenous colitis and those with the characteristic changes were defined to have MC (group A). Colonic biopsies from patients with MC were compared with biopsies from patients with chronic diarrhea but no evidence of MC (group B). One hundred children ages 3 to 12 years with bleeding per rectum were screened and colonic biopsies from 45 patients (group C) who had colonic mucosal changes but no vascular or polyp lesion were compared with patients with MC. Of the 26 patients with chronic diarrhea, MC was found in 5 (3 lymphocytic colitis and 2 collagenous colitis). Significantly higher polymorphonuclear infiltration was seen in group A as compared with group B (13.8 [5.4–20.6] vs 7.2 [0–19.6]; P= 0.03) or group C (13.8 [5.4–20.6] vs 4 [0–13.4]; P= 0.007). Intraepithelial lymphocytes (12 [4–32] vs 4 [0–24]; P= 0.008) and basement membrane thickening (3.5 [2.9–10.6] vs 2.5 [1.6–5.86]; P= 0.008) were also significantly higher in group A as compared with group C. MC was found to be present in children with nonbloody chronic diarrhea in children. Further multicentric studies may provide adequate data on its prevalence.

Some living kidney donors encounter difficulties obtaining life insurance, despite previous surveys of insurance companies reporting otherwise. To better understand the effect of donation on insurability, we contacted offices of life insurance companies in five major cities in Canada to obtain $100 000 of life insurance (20-year term) for 40 fictitious living kidney donors and 40 paired controls. These profiles were matched on age, gender, family history of kidney disease and presence of hypertension. The companies were blinded to data collection. The study protocol was reviewed by the Office of Research Ethics. The main study outcomes were the annual premium quoted and total time spent on the phone with the insurance agent. All donor and control profiles received a quote, with no significant difference in the premium quoted (medians $190 vs. $209, p =0.89). More time was spent on the phone for donor compared to control profiles, but the absolute difference was small (medians 9.5 vs. 7.0 min, p =0.046). Age, gender, family history of kidney disease and new-onset hypertension had no further effect on donor insurability in regression analysis. We found no evidence that kidney donors were disadvantaged in the first step of applying for life insurance. The effect donation has on subsequent phases of insurance underwriting remains to be studied.

Organized retailing is currently in a nascent stage in India. Although Organized retailing, contributes only 4% of total retail at present, will grow by 25–30% every year and become Rs.100,000 crore sector (Rs.1000 billion) by 2010, the organized retailing sector evaluation passes through the four important phases. In India, a number of barriers are found in the way of the development of organized retail market. FDI restrictions on the entry of international retailers in the country, different sales tax rates exists in different states of the country, implementation of VAT, complex cities in the tax structure, problem of funding from the banks, lack of proper infrastructure are constraints on the way of organized retailing. The three biggest challenges of the organized retail industry will be managing manpower, real estate and supply chain. This paper discusses, how Retail sector growth will help various sections of the society and country as whole and what kind of measures government should take for the growth of organized retailing in India?

Unlike the wired networks, congestion measurement in IEEE 802.11 networks is more difficult owing to factors such as time-variant channel capacity and contention among neighbouring nodes. It degrades the throughput and increases delay and packet drops. This paper presents an overview on IEEE 802.11 networks and issue of congestion in them. OPNET simulations were carried out to estimate the effect of congestion situation on the performance of the network model. Simulations were carried out at 11 Mbps data rate except congested node and total simulation time used was 900 simulations-seconds.

We followed 70 adult patients with spinal tuberculosis for a minimum of 2 years. Forty patients were treated by ambulant multi-drug chemotherapy (group A), and 30 with neurological complications (group B) were treated by antero-lateral decompression and chemotherapy. We studied the angle of spinal kyphosis as calculated on lateral spinal X-ray by the modified Konstam’s method. The angle at final follow-up was compared with the pre-treatment angle. The relationship between the amount of initial vertebral loss, the predicted kyphotic angle and the observed kyphotic angle was analysed. Mean initial vertebral loss, mean pre-treatment angle and mean observed kyphotic angle in group A were 0.77°, 24.3°and 31.75° respectively, with a mean increase in angle of 7.4°. In group B, the readings were 0.67 , 25.9° and 26.8° respectively, with a mean increase in angle of 0.9°. Kyphotic deformity continued to progress until 2 years’ follow-up. Progression was more pronounced in the non-operative group.

The purpose of this study was to estimate the average angle of femoral neck anteversion in an Indian population. A total of 300 dry femora were classified by standard anatomical norms into male and female types and left-side and right-side types. They were evaluated by the Kingsley Olmsted and parallelograph methods, and the data were statistically analyzed. The average angles of anteversion obtained were 8.1° and 8.3° by the Kingsley Olmsted and parallelograph methods, respectively. The average femaletype bone showed about 3° more anteversion than the maletype bone. The average left-sided bone showed about 1.6° more anteversion than the right-sided bone. A statistically significant difference existed between the sexes and the sides. The Kingsley Olmsted and parallelograph methods were found to be comparable with a correlation coefficient of 0.99. Altogether, 42.33%, 57.66%, and 79.00% of bones had readings of 5°–10°, 0°–10°, and 0°–15°, respectively. Thus, femoral neck anteversion has been found to be less in the Indian population than in Western populations.

Abstract:  The purpose of this study was to estimate the average angle of femoral neck anteversion in an Indian population. A total of 300 dry femora were classified by standard anatomical norms into male and female types and left-side and right-side types. They were evaluated by the Kingsley Olmsted and parallelograph methods, and the data were statistically analyzed. The average angles of anteversion obtained were 8.1° and 8.3° by the Kingsley Olmsted and parallelograph methods, respectively. The average female-type bone showed about 3° more anteversion than the male-type bone. The average left-sided bone showed about 1.6° more anteversion than the right-sided bone. A statistically significant difference existed between the sexes and the sides. The Kingsley Olmsted and parallelograph methods were found to be comparable with a correlation coefficient of 0.99. Altogether, 42.33%, 57.66%, and 79.00% of bones had readings of 5°–10°, 0°–10°, and 0°–15°, respectively. Thus, femoral neck anteversion has been found to be less in the Indian population than in Western populations.

In this study of the national socio-economic system planning, we describe some of the principles, concepts and applications of a mass-energy based physical system construct for global modelling. The paper synthesizes atleast conceptually, physical, economic, social and institutional aspects of a national activity system into logically consistent theoretical and computational procedures for a coordinated multilevel analysis of mass-energy features. It also presents an illustrative prototype example.

Determining the structure of multi-dimensional data is an important problem in exploratory data analysis and pattern recognition. Clustering methods have been used extensively for this purpose. However, clustering algorithms will locate and specify clusters in data even if none are present. It is therefore appropriate to measure the clustering tendency or randomness of a data set before subjecting it to a clustering algorithm. Hopkins' method of testing for randomness is extended to high dimensions and is tested against data from clustered and hardcore processes along with the Fisher Iris data. As in two dimensions, it appears to be a powerful test for clustering tendency.

Address block location on mail pieces is an important task in postal automation. Unlike personal or business letters which have high degree of global spatial structure among a limited number of entities, mail pieces of magazines usually have an address block printed on a white label which can be pasted in an arbitrary position. Graphics and other printed text on magazine covers also make the address block location problem complicated. In this paper, we present a simple method for automatically locating the address block on color magazine covers based on both color and texture analysis. First, we use a simple color thresholding technique to extract white regions which may contain an address block. Then, a texture segmentation method based on Gabor filters is used to find text regions (including the address) inside the white regions. These text regions are candidates for the address block. Simple heuristics are used to identify the correct address block among these candidates. This method is invariant to rotation and scale of the magazine cover. Experimental results on low resolution (50 dpi) images of several magazine covers are provided to demonstrate the applicability of our method.

A microprocessor-based system for deriving variance-length curves in conjunction with Uster evenness tester has been described with particular reference to jute yams. Reliable variance-length curves can be obtained easily, and the higher CVsoften encountered in jute yarns do not pose any problem. Thick and thin portions of the yarns can also be counted without additional circuitry.

The experimentally observed energy levels for odd–odd normal-deformed, reflection-asymmetric-deformed, and superdeformed nuclei with 57 ≤Z≤ 81 and 87 ≤N≤ 117 are classified according to their intrinsic structures and associated rotational bands. Our literature cutoff date for the data table is August 1995. The article following this one, by B. Singh et al., updates the literature cutoff to March 1998.

In image processing, we often encounter large vector AR models whose coefficient matrices are usually sparse and have a Toeplitz structure.

Short courses of cyproterone acetate, a compound with progestational and antiandrogenic activities, were administered to normally menstruating women during different phases of the menstrual cycle to suppress growth and maturation of the follicles and corpus luteum function.

A multi-view representation scheme and a multi-matching strategy for 3D object recognition are described; 3D objects are represented in terms of their 2D appearances so that 2D techniques can be applied to 3D recognition. Appearances of objects in the representation scheme are further organized in a hierarchical manner so that the matching process can reduce its search space by examining only the optimal view at every level of the representation scheme. In our multi-matching strategy, the matching module is composed of four components: point matcher, string matcher, vector matcher, and chamfer matcher. Each matcher is associated with a termination rule so that impossible views can be rejected at the early stages of the matching process. Experimental results reveal that the proposed strategies are feasible for 3D object recognition.

We describe a system for obtaining a "generic" parts-based 3D object representation. We use range image data as the input, obtaining a 3D object representation based on 12 geon-like 3D part primitives as the output. The 3D parts-based representation consists of parts detected in the image and their identities. Unlike previous work, we do not make simplifying assumptions such as the availability of perfect line drawings, perfect segmentation, or manual segmentation.We propose a novel method of specifying "generic" 3D parts, i.e., by means of surface adjacency graphs (SAGs). Using the SAGs, we derive an extremely compact multi-view representation of the part primitives, consisting of a total of only 74 views for all 12 primitives. Based on the multi-view representation of parts, we present a method of performing part segmentation from range images, given a good surface segmentation. This method for partsegmentation is more general than common approaches based on Hoffman and Richards' "principle of transversality." We present two approaches for identifying the parts as one of the 12 3D part primitives. The first approach applies statistical pattern classification methods using parameters estimated by superquadric fitting. Five features derived from the estimated superquadric parameters are used to distinguish between the 12 part primitives. Classification error rates are estimated for k-nearest-neighbor and binary tree classifiers, for real as well as for synthetic range images. The second approach for part identification draws inferences from the distribution of angles between surface normals and the principal axis of a part.We show that intensity data can be used to recover from some misclassifications yielded by the purely range-based methods of part identification. A simple test is applied to check the concavity or convexity of the part silhouette in the intensity image. This serves as a reliable test of whether the part axis is straight orcurved.Results of part segmentation and identification are presented for real range images of several multi-part objects. Our system successfully performs part segmentation and identifies the parts.Copyright 1994, 1999 Academic Press, Inc.

The preceding article, “Intrinsic Structures and Associated Rotational Bands in Medium-Heavy Deformed Odd–Odd Nuclei, I,” by D. M. Headly et al., presents the experimentally observed energy levels of odd–odd nuclei with 57 ≤Z≤ 81 and 87 ≤N≤ 117 with a literature cutoff date of August 1995. This supplement updates the experimental data specifically dealing with level structures of these nuclei through March 1998.

Model-based 3D object recognition systems using range imagery typically employ entirely data-driven procedures for segmentation and surface classification. However, some recognition environments may contain only objects whose surface types and parameters are known a priori and can therefore be exploited by the early-processing steps used in the recognition system. We propose a new suite of model-driven techniques for identification of quadric surfaces (cones, cylinders, and spheres) in segmented range imagery. The methods employ surface positions and surface normal estimates in combination with the known parameters of surfaces in a database of object models. Second-derivative quantities (i.e., surface curvatures) are not used. The free parameters of cylinders and spheres are accumulated using a Hough transform, and free parameters of cones are estimated using a regression procedure. Experiments are presented for numerous scenes of both real and synthetic objects including part jumbles, objects in many poses, objects containing concave and convex surfaces, and noiseless and noisy synthetic range images of objects. Our experimental results show that the proposed surface classification methods can accurately recover surface parameters from both synthetic and real images, making them viable for environments with partial knowledge of surface type and parameters.Copyright 1993, 1999 Academic Press

A parametric study is conducted to investigate the influence of some of the nonlinear effects produced by the variable submergence and the methods used for calculating hydro-dynamic forces, on the dynamic response of Tension Leg Platforms. The nonlinear effects included in the study are the variable added mass and the tension fluctuation in the tethers produced due to the variable buoyancy and the vertical wave forces. In addition, the nonlinearity due to relative-velocity squared drag force is considered. Hydrodynamic forces on the large diameter members of the super structure are obtained by means of modified Morison’s equation using (i) average water particle kinematics across the diameter of the members, (ii) water particle kinematics calculated at the centre of the cross-section, and (iii) water particle kinematics same as (ii) above, but the inertia coefficient is modified to take into account any diffraction effect. The effect of variable submergence on the water particle kinematics is included by both Chakrabarti’s [1] and Hogben’s [2] approaches. The nonlinear equation of motion is solved in time domain by using iterative step by step integration procedure. Two integration algorithms namely. Newmark’s – beta-method and Argyris 3rd order integration scheme have been used. Relative efficiencies of the two integration schemes have been examined in relation to obtaining the steady-state surge response of the T.L.P.

Determination of the fault-plane solution of the Kinnaur earthquake by first motion and amplitude data of P waves, along with other geological and geophysical data, indicates a N–S-trending and westward-dipping fault plane with purely dip-slip displacement. This plane coincides with the N–S extending zone of aftershocks, ground fissures and faults observed in the epicentral tract following the earthquake. The cumulative strain release pattern displays a characteristic release of logarithmic recovery followed by exponential recovery. The aftershocks display a notable migration in space. They also show two distinct phases of seismic activity. The main earthquake is estimated to have a fault length of 25 km, fault area of 575 km 2, volume of strain of ~2900 km 3, displacement of 59 cm, stress drop of 36 bars, and strain release of 5.9 · 10 −5.

We propose a new texture-based language-free page segmentation algorithm which automatically extracts the text, halftone, and line-drawing regions from input greyscale document images. This approach utilizes a neural network to train a set of masks which is optimal for discriminating the three main texture classes in the page segmentation problem: halftone, background, and text and line-drawing regions. The text and line-drawing regions are further discriminated based on connectivity analysis. We have applied the algorithm to successfully segment English and Chinese document images. We also demonstrate that the masks can perform language separation (English/Chinese) when appropriately trained.

Soft-sediment deformational structures from the Himalayan Arc, caused by episodic earthquake recurrences during the Holocene (Recent), are produced by the ongoing tectonic processes. These small-scale, subtle structures occur along some major thrusts in the Garhwal Himalaya and vary from normal faults in the lower zone to compressional structures in the middle zone along the Main Central Thrust in the Tons Valley. The latter includes isoclinal, angular, kink and disharmonic folds (with discrete displacements along their axial surfaces), thrusts with décollement, listric and overstep thrusts in duplex style, and load slumping. The upper zone is marked by very low-angle thrusts with left-lateral displacement and associated displacement shears (D), Riedel shears (R) and thrust shears (P) as well as small-scale sporadic kinks. Three zones reveal changing tectonic character from gravity tectonics in the lower zone to compression in both the middle and upper zones with the maximum principal stress σ 1oriented N60° to N110° respectively. Along the Tons Thrust, post-depositional structures include drag along normal fault zone characterized by D-, R- and P-shears and conjugate fractures that provide localized orientation of stresses: σ 1at 75/N60°, σ 2at 12/N280° and σ 3at 12/N290°.

A solid membrane sensor has been fabricated using basic lead sulphate as an elecroactive phase. Preliminary investigations with the membrane exhibit promising selectivity for chromate ions, which can be estimated in the concentration range 2×10−51×10−1M at pH 7−10. The potential generated across the membrane is reproducible and the response time is 20 s. The electrode also works well in a partially non-aqueous medium. The Electrode is selective over a number of monovalent, bivalent and polyvalent anions. It can be used for the estimation of CrO42−by potentiometric titrations with Pb2+ions. Estimation of chromium in the waste from the electroplating industry has successfully been achieved with this membrane sensor.

An integrated geological analysis of the Himalaya and Indo-Gangetic Plains demonstrates that the Great Vindhyan Basin incorporating large parts of these morphotectonic units were uplifted into an uneven landmass due to the Pre-Mesozoic orogenic cycle. This uneven landmass was eroded off largely during a considerable part of the Devonian and Carboniferous thereby causing partial absence of sedimentary sequences of these periods except in parts of the Tethys Himalaya. The Late Paleozoic epeirogenic movements brought about renewed sedimentation in the Lesser and Tethys Himalayas in the Krol and Tethys Basins, respectively, which was terminated by the Himalayan Orogeny during Late Cretaceous—Early Eocene.

A technique for generating independent transform coefficients from any p-dependent signal has been developed. Since these coefficients are independent, the Lloyd-Max quantization efficiency is improved. In addition, these coefficients are shown to be Gaussian distributed. Therefore, the probability density function estimate is bypassed during the quantizer design. An all-pass (encryption) pre-filter is required by the proposed technique, and the filtered signal is obtained efficiently by an algorithm developed in this paper. An added benefit of this technique is the compatibility and higher security with respect to the conventional transform coding (TC), and the method is called the transform encryption coding(TEC). In addition, a post-filter is necessary for signal reconstruction. Due to the all-pass nature of the pre/post-filtering process, the mean-square quantization error for the complete process is equal to that for the intermediate independent Gaussian transform coefficients. Simulation results show TEC achieves about 1 dB coding gain compared with TC. Coded images without blocking effects are obtained at 0.5 bit/pixel (bpp) using TEC. The image quality is similar to that obtained by TC at 1 bpp. Even at 0.35 bpp, TEC performs in the same way as the recent ‘DCT/DST’ technique of Rose et al. (1990) and shows no blocking effects. Most significantly, TEC encoded image is insensitive and robust to the channel noise.

cutaneous involevemtn is an important extrapulmonary manifestation of tuberculosis. It is a paucibacillary condition and has diverse clinical presentations. Sufficient data is not available regarding role of GeneXpertMTB/RIF in cutanoues tuberculosis.

The Global Carbon Budget 2018 (GCB2018) estimated by the atmospheric CO 2growth rate, fossil fuel emissions, and modeled (bottom‐up) land and ocean fluxes cannot be fully closed, leading to a “budget imbalance,” highlighting uncertainties in GCB components. However, no systematic analysis has been performed on which regions or processes contribute to this term. To obtain deeper insight on the sources of uncertainty in global and regional carbon budgets, we analyzed differences in Net Biome Productivity (NBP) for all possible combinations of bottom‐up and top‐down data sets in GCB2018: (i) 16 dynamic global vegetation models (DGVMs), and (ii) 5 atmospheric inversions that match the atmospheric CO 2growth rate. We find that the global mismatch between the two ensembles matches well the GCB2018 budget imbalance, with Brazil, Southeast Asia, and Oceania as the largest contributors. Differences between DGVMs dominate global mismatches, while at regional scale differences between inversions contribute the most to uncertainty. At both global and regional scales, disagreement on NBP interannual variability between the two approaches explains a large fraction of differences. We attribute this mismatch to distinct responses to El Niño–Southern Oscillation variability between DGVMs and inversions and to uncertainties in land use change emissions, especially in South America and Southeast Asia. We identify key needs to reduce uncertainty in carbon budgets: reducing uncertainty in atmospheric inversions (e.g., through more observations in the tropics) and in land use change fluxes, including more land use processes and evaluating land use transitions (e.g., using high‐resolution remote‐sensing), and, finally, improving tropical hydroecological processes and fire representation within DGVMs. Top‐down and bottom‐up estimates of net land‐atmosphere CO 2fluxes agree well globally but show important mismatches at regional scalesRegional mismatches are dominated by differences between inversions and interannual variability in CO 2fluxesMismatches between top‐down and bottom‐up data sets are explained by sensitivity to climate and by uncertainty in land use change forcing

Transmission electron microscopy (TEM) at high magnification of thin cross-sections of drawn multifilament poly (ethylene terephthalate) yarn and of this yarn after heat-setting in the slack state at 250°C and in the taut state at 258°C is shown to provide evidence for the existence of crystallites whose lateral dimensions are consistent with those measured from wide-angle X-ray diffraction (WAXD). The denser, crystalline microfibrils appear to be separated by interfibrillar material of lower density in all the samples examined. The electron micrographs bring out the important differences in the morphologies of the three samples, the implications of which are critically examined. © 1997 Elsevier Science Ltd.