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Summary. The Haemophilia Utilization Group Study (HUGS) was created 10 years ago to examine the annual utilization and cost of haemophilia-related healthcare services. Retrospective chart reviews for 336 patients with haemophilia A receiving treatment in one of five comprehensive haemophilia treatment centres (HTCs) during 1995 were completed through interview of the provider. This method provided adequate collection of data from patient charts without the abstractor having direct access to patient health information. Utilization data were used to impute the costs of different components of care (e.g. physician visits, factor VIII concentrate, emergency room, hospitalization). The total annual cost of care was $139 102 (SD $304 033). Factor VIII concentrate costs comprised the largest proportion of these costs; mean factor VIII concentrate use was 128 517 units per patient per year. Unbilled physician utilization accounted for 7.8% of the mean total physician costs per annum, while mean allied healthcare costs accounted for 33.5% of the total annual allied healthcare costs per patient. In the ordinary least-squares regression model, higher costs were associated with severe factor VIII deficiency, arthropathy, more comorbid conditions, an inhibitor to factor VIII concentrate, infusing through a port and prophylaxis. Although factor VIII concentrate is the most costly component, the treatment of haemophilia uses many healthcare resources. HUGS has demonstrated that patient clinical characteristics and physician practices predominantly drive the costs of haemophilia care. Specifically, patients with more severe arthropathy had greater healthcare costs. As future funding decisions are made, it is important to provide for all components of care.

Summary. Objective: The main objective of this study was to examine factors associated with utilization and costs for persons with haemophilia. Study design: Utilization data and patient characteristics were collected through medical record review of 336 patients receiving treatment for at least 90% of their haemophilia care at one of five comprehensive haemophilia treatment centres in California. Principal findings: The range of factor VIII deficiency in our sample was similar to the distribution among haemophilic patients in the Western United States; 215 (64%) had severe FVIII deficiency. The mean age in our sample was 21.4 (SD ¼ 16.2) years old and 114 (34%) were HIV-positive. In the multivariate model predicting the total cost of health care during 1995 (adjusted R 2 ¼ 0.40), total annual costs were significantly (P < 0.05) associated with being HIV-seropositive, infusing FVIII concentrate through a port vs. i.v. infusion, the number of comorbidities, moderate arthropathy (compared with no arthropathy), mild arthropathy, history of inhibitor to FVIII, and current prophylactic FVIII concentrate infusion. Conclusion: As expected, total health-care costs were correlated with comorbid medical conditions, such as HIV and sequelae of haemophilia such as arthropathy. Health policy should consider risk adjustment for the presence of complications such as arthropathy and HIV infection in the financing of haemophilia treatment to promote more equitable delivery of these services.

The purpose of this study was to assess the relationship between health care and utilization of that health care, and to provide a base measurement of health status in patients with haemophilia. Provider interview and retrospective chart review of 336 patients with haemophilia treated during 1995 at one of five comprehensive haemophilia treatment centres was conducted to measure patient health status characteristics and utilization of health care. Two health status scales were included. The first, the Self-Care Measure, was a four-point single item scale measuring the patient's ability for basic self-care, which was scored by a chart review and an interview with the health-care provider. The second, the Haemophilia Utilization Group Study (HUGS) Functional Status Measure, is a four-item, 10-point scale developed specifically for patients with haemophilia. Our sample represents 27% of actively treated patients in region IX. The mean score on the HUGS Functional Status Measure was 8.7 (SD=2.4). The HUGS scale exhibited a ceiling effect across all four scales: attitude (n=269, 80.1%), overall wellbeing (n=263, 78.3%), working (n=254, 75.6%) and orthopaedic status (n=195, 58.0%). Both higher total health-care costs and factor VIII annual costs were significantly associated with lower scores on the HUGS Functional Status Measure. Health status is a critical component in the assessment of the utilization and outcomes of care. In the absence of the availability of a patient interview, the HUGS Functional Status Measure can be used as one characteristic that explains the variation in the utilization of health care by patients with haemophilia.

The main objective of this study was to examine factors associated with utilization and costs for persons with haemophilia.Utilization data and patient characteristics were collected through medical record review of 336 patients receiving treatment for at least 90% of their haemophilia care at one of five comprehensive haemophilia treatment centres in California.The range of factor VIII deficiency in our sample was similar to the distribution among haemophilic patients in the Western United States; 215 (64%) had severe FVIII deficiency. The mean age in our sample was 21.4 (SD = 16.2) years old and 114 (34%) were HIV-positive. In the multivariate model predicting the total cost of health care during 1995 (adjusted R2 = 0.40), total annual costs were significantly (P0.05) associated with being HIV-seropositive, infusing FVIII concentrate through a port vs. i.v. infusion, the number of comorbidities, moderate arthropathy (compared with no arthropathy), mild arthropathy, history of inhibitor to FVIII, and current prophylactic FVIII concentrate infusion.As expected, total health-care costs were correlated with comorbid medical conditions, such as HIV and sequelae of haemophilia such as arthropathy. Health policy should consider risk adjustment for the presence of complications such as arthropathy and HIV infection in the financing of haemophilia treatment to promote more equitable delivery of these services.

The purpose of this study was to assess the relationship between health care and utilization of that health care, and to provide a base measurement of health status in patients with haemophilia. Provider interview and retrospective chart review of 336 patients with haemophilia treated during 1995 at one of five comprehensive haemophilia treatment centres was conducted to measure patient health status characteristics and utilization of health care. Two health status scales were included. The first, the Self-Care Measure, was a four-point single item scale measuring the patient's ability for basic self-care, which was scored by a chart review and an interview with the health-care provider. The second, the Haemophilia Utilization Group Study (HUGS) Functional Status Measure, is a four-item, 10-point scale developed specifically for patients with haemophilia. Our sample represents 27% of actively treated patients in region IX. The mean score on the HUGS Functional Status Measure was 8.7 (SD=2.4). The HUGS scale exhibited a ceiling effect across all four scales: attitude (n=269, 80.1%), overall wellbeing (n=263, 78.3%), working (n=254, 75.6%) and orthopaedic status (n=195, 58.0%). Both higher total health-care costs and factor VIII annual costs were significantly associated with lower scores on the HUGS Functional Status Measure. Health status is a critical component in the assessment of the utilization and outcomes of care. In the absence of the availability of a patient interview, the HUGS Functional Status Measure can be used as one characteristic that explains the variation in the utilization of health care by patients with haemophilia.

Mariners' judgment of minimum safe overtaking distance (MSOD) in fog varies considerably from person to person. Many are prepared to pass too close and are unaware of the risk they are taking. Others are overcautious and leave more sea-room than is necessary. This paper compares calculated values of MSOD in fog with the distances at which subjects in a radar simulator were prepared to overtake. The results are analysed, firstly to help the mariner and those responsible for his education so that the dangers may be better understood and thereby avoided, and secondly to assist the marine traffic engineer responsible for the planning of separation schemes which need to be designed to accommodate over taking.

This account of a recent simulator experiment at the City of London Polytechnic on encounter reaction times at sea will also be published as an internal National Maritime Institute report.Two ships are said to have an encounter when they pass within a certain distance of one another, say half a mile. The encounter rate bears a relation to the collision rate in a given area of sea and consequently it is desirable to minimize the encounter rate. The effect of routing in sea areas with a high density of shipping has been to reduce the total number of encounters but to increase the number of overtakings. Thus the introduction of a routing scheme greatly increases the proportion of overtaking encounters in the main lanes. For example, the routing scheme in the Dover Strait (with I per cent of through rogues) has increased the proportion of potential overtaking encounters from 27 to 95 per cent.

Two main concepts in mathematical modelling of ship encounters have been proposed by Davis. The first, the ‘domain’, was an adaptation of a concept originally introduced by Goodwin, who defined the domain as the ‘area about own-ship that a navigator wished to keep free with respect to ships and other stationary objects’. The second, the ‘arena’, conceived by Davis, is the area around the domain which when infringed causes the mariner to consider whether to make a collision-avoidance manoeuvre. Thus, in a computer model, when a vessel enters the arena the computer analyses the situation and, depending on the severity of the threat, makes a collision-avoidance manoeuvre.Goodwin's domain was divided into three sectors corresponding to the ‘giveway’, the ‘stand-on’ and the ‘overtaking’ regions as defined by the relative velocity of approach. The domain was derived from radar films of ship tracks and records of radar simulator experiments. Davis smoothed the sectored domain to a circle with own-ship off-centred astern and to port, and the weighting of each of the sectors retained. Davis's domain had a solid theoretical grounding; the arena, however, was simply a larger version of the smoothed domain. Its size and position were obtained by means of a well-distributed questionnaire. It served its purpose in the model, but lacked any real validation.One problem with the Davis arena was its inability automatically to take into account different velocities, both of own-ship and of targets.

In a previous paper a model was outlined for an encounter between two vessels using the ‘range to domain over range rate’ (RDRR) criterion. This paper shows how the model has been developed to simulate traffic flow and collision avoidance through the main south-west bound lane of the Dover Strait traffic separation scheme. B. A. Colley and C. T. Stockel are at Plymouth Polytechnic, R. G. Curtis with the Department of Trade and Industry. The paper was presented at an ordinary meeting held in London on 16 November 1983.

When measurements and observations are made using a radar simulator, the researcher assumes that mariners behave in the same way, whether they are handling a simulator or a real ship. This paper, which was presented at an Ordinary Meeting of the Institute held in London on 22 April 1980, investigates whether this is a reasonable assumption.

An application of the model to manoeuvre ships based on the range to domain over range rate (RDRR) concept is described. A simulation of a training simulator has been set up on which the target ships manoeuvre by the RDRR model in response to mariner controlled ships. Results of experiments show that the RDRR model manoeuvres targets realistically. The applications are reduced instructor work load and increased simulator reality. The method has the potential for development to manoeuvre ships at sea.B. A. Colley is now with Plessey Marine, R. G. Curtis is with the Department of Trade and Industry and C. T. Stockel is at Plymouth Polytechnic.

An approximate method of obtaining the surface‐wave reflection coefficient of a step is developed. Numerical results are presented for Bleustein‐Gulyaev and Rayleigh waves reflected at normal incidence from electrodes of aluminum and gold on a piezoelectric ceramic. The results show good agreement with results previously obtained using a more exact but much longer method. The method is easily extended to any crystal symmetry.

A theoretical analysis of the reflection, transmission, and bulk wave scattering of Bleustein‐Gulyaev waves by an electrode of finite thickness and finite length is conducted. The surface region outside the electrode is assumed to be coated with an infinitely thin perfectly conducting metal layer, since without this layer the surface wave would be so deeply penetrating that it would be of little interest. The theory uses Green’s function and Fourier transform techniques and does not involve any physical approximations; the near‐field part of the Green’s function being evaluated numerically after simplification by contour integration. The method could be extended to deal with a general surface wave. Numerical results are presented for aluminum and gold layers on PZT‐4 ceramic. A series of such reflectors cascaded together is also considered.

Theory of the propagation of a surface wave related both to Bleustein‐Gulyaev waves and Love waves is developed. The wave has unidirectional particle motion perpendicular to the direction of propagation and parallel to the surface of a piezoelectric material which is covered with a finite‐thickness layer of an isotropic conducting material. An equation relating phase velocity to material costants is solved in closed form for a piezoelectric material of class 6mm, and conditions for the existence of various modes are presented. Piezoelectricity allows a nonleaky but dispersive wave to exist under conditions is which no love wave is possible, namely, when the shear wave velocity in the layer is greater than that in the substrate. Numerical results are presented for aluminium, gold, and zinc layers on PZT 4 ceramic.

A number of metallic oxides and carbonates may be used as catalysts for the preparation of dialkyl ketones from higher fatty acids in the liquid phase. All cause violent frothing which can be controlled by adding the fatty acid gradually to the catalyst at the reaction temperature. The various metallic oxide and carbonate catalysts are compared and magnesium oxide is selected as most suited for the commercial preparation of ketones. The most suitable reaction temperature range is 330—360°. The crude ketone is greasy, but its properties arc greatly improved by pressing. During the reaction carbon dioxide is evolved in an amount equal to 94% of that required for complete ketonisation. Small amounts of carbon monoxide and other gases arc also formed. The progress of the reaction has been followed by measurement of the rate of liberation of carbon dioxide and the results arc shown to agree with the supposition that a keto-acid arises as an intermediate in the formation of ketones. Interruption of the reaction and estimation of the unchanged acid present, together with a knowledge of the amount of carbon dioxide then liberated, allows the amount of keto-acid present in the reaction mixture to be calculated. This is found to be constant during the early stages of the reaction, but increases greatly when the reaction becomes violent. It is suggested that formation of the salt of the keto-acid is the rate-determining reaction and that this reaction is catalysed by the metallic oxide used.

RECENTLY, the molecular structure of lanostadienol (lanosterol), C30H50O, an important ‘triterpenoid’ constituent of wool-wax, has been studied intensively. Ruzicka et al.1 and Barton, McGhie et al.2 have suggested three possible formulae and, considering the evidence available, were unable to decide between them. Earlier, We had begun an X-ray structure analysis to provide unequivocal proof of the molecular structure of lanostadienol. This investigation has provided, in addition, a complete description of the stereochemistry of the molecule, avoiding the complex orthodox methods of stereochemistry. From earlier Work, lanostadienol is known to contain four rings, one inert double-bond and one active double bond in the terminal isopropylidene group of the long side-chain. Hydrogenation of the active double-bond yields lanostenol, and the iodoacetate of this compound3 was selected as a suitable ‘heavy-atom’ derivative for the structure analysis.

Liquid-vapour equilibrium data are reported for the furfural-water system at pressures of 6.17, 7.85, and 9.83 kg. per cm2. Under these pressures the system forms a homoazeotropic mixture differing only slightly in composition from the heteroazeotropic mixture formed at normal pressures. The data are checked by the calculation of activity coefficients. Abnormal activity coefficients are found for water in mixtures of high furfural content. The equation log10 P= -2209/T + 7.959 fits published data and that now reported for t'he vapour pressure of furfural over the range of pressures 100 to 6,000 mm. Hg. Changes in the mutual solubilities of furfural and water caused by the addition of metallic sulphates are determined. All the sulphates examined raised the critical solution temperat'ure, sodium sulphate being most effective. With magnesium sulphate there was a region of discontinuity, which may possibly be attributed to a change of phase or of hydration of magnesium sulphate. The velocities of reaction (decomposition or polymerization) of furfural in aqueous and in aqueous acidic medium at 180°C. are reported. The data are used to estimate the amount of furfural lost by such reactions in a commercial process for the production of furfural. It is considered that the use of metallic sulphat'es in the commercial prociuotion of furfural should not influence the yield appreciably.