Arterial Surgery in Intermittent Claudication

The results of a survey of 302 operations in 277 patients during 1959-70 are presented, and an additional 69 operations during 1971 are included in the mortality figures. Operative mortality (1968-71) was 0·9% in 113 aortoiliac operations and nil in 96 femoropopliteal operations.Immediate patency rates on dismissal from hospital exceeded 95%, and the five-year patency rate for aortoiliac operations was just over 70% and for femoropopliteal operations 60%.     

The impact of operations redesign on the safety stock investment in supply chains

This study is motivated by a real problem encountered in the manufacturing and distribution process at a local electronic manufacturer of security devices. We investigate the impact of operations redesign (i.e., operations merging) on the cost of safety stock in a supply chain. A simple safety stock method is used to derive a model for estimating safety stock levels. Our result shows that operations redesign can have a significant impact on safety stock investment. We extend and complement the existing literature in the following aspects: (i) we address the issue of safety stock deployment, i.e., we not only investigate the problem of how many operations should be delayed, but also determine which operations need to be delayed, (ii) we provide an efficient heuristic algorithm to determine which operations need to be merged, and (iii) we find the optimal operations redesign strategies under some special cases. Our analysis also reveals some important conditions and insights for better operations redesign, which enable us not only to decide when an operations redesign is appropriate, but also to suggest the scale and the format of the operations redesign.     

Testing Methods: The Evaluation of Discovery Operations in Evolutionary Biology

Scientific discovery requires both abstract, theoretically defined concepts and discovery operations formed by sets of rules that permit the empirical detection of instances of those concepts. In this paper, I examine the ontological status of discovery operations and the tests employed to evaluate them in evolutionary biology. Attention is drawn to the distinction between nomothetic (universal, predictive) and ideographic (historical, retrodictive) discovery operations, and between complementary and exclusive discovery operations. Three types of tests of discovery operations are commonly employed in evolutionary biology. Theoretical tests aim to show that a discovery operation is inconsistent with accepted, well-corroborated, empirical theories. Empirical tests evaluate the performance of competing discovery operations in terms of their results when applied to the same empirical data sets. Philosophical tests aim to show that an operation is inconsistent with logical and epistemological principles. Appropriately designed theoretical and philosophical tests of ideographic discovery operations may be scientifically valid. Empirical tests, however, are incapable of evaluating the scientific merits of competing discovery operations. Nonetheless, empirical comparisons (not tests ) of competing discovery operations may provide insight into the ways discovery operations may be misleading and therefore may play an important role in stimulating critical debate and eventually establishing a scientifically optimal operation. In practice, theoretical and philosophical tests are often combined to test competing discovery operations as rigorously as possible.     

Surgical training: an objective assessment of recent changes for a single health board.

The reduction in doctors'' hours and the introduction of specialist training have reduced general surgical training by 60%. This study assessed the implications for a single health board. A questionnaire listing 13 representative operations was sent to 44 trainees and 52 trainers to determine the number of operations a trainee should perform. The total number of operations required for training was compared against the total actually performed across the health board. Operating times for five representative operations were audited prospectively. Trainers and trainees recommended a similar and conservative number of operations. The total number of operations available for training (4913) was 38% less than the number recommended (7946). Trainees required 50-75% more operating time than consultants. To increase the proportion of operations undertaken by trainees from the current 30% to 70% would require an extra 270 theatre days (of pounds 1.3m) yearly. The minimum number of operations required for training must be defined and the proportion of supervised operations undertaken by trainees substantially increased. Service and financial implications will have to be addressed. Action is needed urgently, as the first trainees will become consultants in less than five years.     

Comparison of impact between carrot and cereal 1080 baits on tomtits (

This study investigates the hypothesis that tomtits are significantly less susceptible to 1080 poison operations when cereal rather than carrot bait applications are used, both at relatively low sowing rates. We made counts of territorial male tomtits along transects during standard 1080 possum control operations in 2001 to 2003. The transects had 3?5 kg ha-1 sowing rates of either carrot or cereal baits. The case-study evidence, all from operations that reduced possum populations to below five percent residual trap-catch, indicates that cereal bait operations with low sowing rates and large bait size have little, if any, immediate impact on tomtit populations. These results should be taken into account when planning aerial 1080 operations, especially given the contrasting evidence that carrot operations, even at low sowing rates, can have a negative impact on tomtits.     

Operations upon the aged

From the point of view of the surgeon, as repeatedly emphasized in the surgical literature, the mortality rate for operations upon old persons is only slightly higher for elective surgical operations than for the same operations on younger persons when proper preoperative and postoperative precautions are taken. However, the mortality rate for emergency operations is much higher in old persons than in younger ones. Many surgeons believe, therefore, that disease for which operation is otherwise indicated should be treated surgically irrespective of the age of the patient per se. The authors' experience with operations upon old persons at the San Francisco Hospital accords with these conclusions.     

OPERATIONS UPON THE AGED

From the point of view of the surgeon, as repeatedly emphasized in the surgical literature, the mortality rate for operations upon old persons is only slightly higher for elective surgical operations than for the same operations on younger persons when proper preoperative and postoperative precautions are taken. However, the mortality rate for emergency operations is much higher in old persons than in younger ones. Many surgeons believe, therefore, that disease for which operation is otherwise indicated should be treated surgically irrespective of the age of the patient per se.The authors'' experience with operations upon old persons at the San Francisco Hospital accords with these conclusions.     

Surgery and anesthesia in Ontario.

Operative and case-fatality rates in Ontario for eight elective (discretionary) and seven nonelective (nondiscretionary) operations and the proportions of these operations and their anesthetic procedures performed by general practitioners were calculated. Cholecystectomy increased in frequency 32% from 1968 through 1973, tonsillectomy and adenoidectomy decreased 37%, and hysterectomy increased 41%. Except for colectomy the rates for nonelective operations changed only slightly over the 6 years. Case-fatality rates (hospital deaths per 10000 operations) for the discretionary operations in 1973 were as follows: extraction of lens, 23.1; tonsillectomy and adenoidectomy, 0.4 (2 deaths among 52938 operations); varicose vein stripping, 6.1; nonrecurrent inguinal herniorrhaphy, 21.9; cholecystectomy, 61.0; hemorrhoidectomy, 9.8; prostatectomy, 115.9; and hysterectomy, 9.6. In 1973 general practitioners did 32% of tonsillectomies and adenoidectomies (61% in 1971), 10 to 20% of inguinal herniorrhaphies, hemorrhoidectomies and appendectomies and 6% or less of the other operations. However, they performed 35% or more of the anesthetic procedures for these four operations as well as for varicose vein stripping, cholecystectomy and hysterectomy. Rates of general-practice surgery and anesthesia in an urban centre in Ontario were substantially less than those for the province as a whole.     

Measures of early postoperative mortality: beyond hospital fatality rates.

OBJECTIVE--To quantify the short term risk of postoperative mortality in ways which take account of deaths after discharge and the background risks of death in patients who come to operation. DESIGN--Analysis of linked abstracts of hospital admission records and death certificates for common operations. SETTING--Six health districts in the Oxford region. SUBJECTS--Records of 223,529 operations performed in 1980-6. MAIN OUTCOME MEASURES--In hospital fatality rates, case fatality rates, and standardised mortality ratios at selected time periods during the year after operation and the ratio of early (< 30 days) to late (90-364 days after operation) fatality rates. RESULTS--Fatality rates throughout the year after operations performed after emergency admissions were generally higher than those for similar operations performed after elective admissions and higher than expected from population rates. Examples were prostatectomy, hip arthroplasty, inguinal herniorrhaphy, and cholecystectomy. Common elective operations such as inguinal herniorrhaphy and cataract operations showed no early peak in mortality, but others did. These included transurethral prostatectomy (ratio of early to late mortality 2.0; 95% confidence interval 1.3 to 2.6), hysterectomy (3.2; 1.5 to 6.6), hip arthroplasty (3.8; 2.5 to 5.4), and cholecystectomy (6.9; 4.3 to 11.1). CONCLUSIONS--Temporal profiles of death rates in the year after operation show which operations have early peaks in mortality and which do not. Emergency and elective operations have very different profiles and should be analysed separately. For elective operations for conditions which pose no immediate threat to life the ratio of early to later fatality rates provides a measure of increase in mortality after operation while allowing for the background risk of death in the patient groups.     

Seaside operations in container terminals: literature overview,trends, and research directions

Seaside operations are considered the bottleneck operation in most container terminals around the world. This paper presents an in-depth updated overview of the seaside operations at container terminals and highlights current trends and developments. We review and classify scientific journal papers on container terminal seaside operations, published between 2004 and 2012. The paper also discusses and challenges the current operational paradigms on seaside operations. Lastly, the paper identifies new avenues for academic research based on current trends and developments in the container terminal industry.     

Use and abuse of performance indicators.

An audit was performed by this department after allegations by the regional health authority of low productivity. It was found that the health authority had underestimated the number of operations performed in 1983 by only 5%, but an inexact classification and grading of operations had led to errors in the performance indicators of 19.8% for the "weighted number of operations" and 34.5% for the "number of major operations per consultant." When the throughput of orthopaedic departments in districts was compared by the regional health authority it was found that such errors in performance indicators had been further compounded by the inconsistent use of population data and incorrect data on medical staffing. Medical practitioners and the health authorities are alerted to this amplification of inaccurate data. Other methods for assessing trauma and orthopaedic surgery are proposed, such as a simplification of the Office of Population Censuses and Surveys classification of surgical operations, grading operations based on time spent in the operating theatre, and provision of computer programs to code for diagnosis and operation when writing discharge summaries.     

Caseload or workload? Scoring complexity of operative procedures as a means of analysing workload.

OBJECTIVE--To present a more realistic assessment of surgical workload than that provided by a case count. DESIGN--Prospective study of all the operative procedures performed in one year, classified according to the British United Provident Association''s schedule of procedures and scored by the "intermediate equivalent" value (taking the recommended fee value of an intermediate operation as 1.0) compared with the number of operations performed. SETTING--General surgical unit of Taunton and Somerset Hospital, comparing four consultant surgeons and their teams. PATIENTS--Inpatients and day patients admitted under the care of general surgeons during 1989. MAIN OUTCOME MEASURE--Difference between the apparent workload represented by simple case counting (caseload) and the actual workload represented by calculation of the total "intermediate equivalent" value. RESULTS--The workload assessed in terms of intermediate equivalent values was greater than that suggested by case counting for complex operations (12% v 4%), operations at the district hospital (82% v 74%), and operations performed by consultants (53% v 35%) and was lower for minor operations (20% v 42%), operations at the community hospitals (18% v 26%), and operations performed by surgeons in training grades and clinical assistants (47% v 66%). CONCLUSIONS--The use of the intermediate equivalent values as an indicator of complexity allows a more realistic assessment of the operative workload than a simple case count of the number of different operations and is recommended for comparing workload in different hospitals and departments.     

Use of neurosurgery for psychological disorder in British Isles during 1974--6.

All 44 neurosurgical units in the British Isles replied to a postal questionnaire asking about their use of neurosurgery during 1974--6 for functional mental illness. A total of 431 operations was reported, representing a yearly rate of 3.4 operations per million population aged over 15. The numbers of operations declined from 158 in 1974 to 119 in 1976. Four units did two-thirds of the operations. Stereotactic methods for locating the site for the lesion were used in two-thirds of procedures. Mood disorders, anxiety states, and obsessive-compulsive neurosis were the conditions most commonly treated.     

Some recent advance in thoracic surgery

In this brief presentation of some recent advances in thoracic surgery a number of miscellaneous topics which deserve consideration at this time are discussed. Among these are acidosis during anesthesia for thoracic operations, the problem of esophagitis in relation to surgery, recent improvements and reorientations in pulmonary operations, and some comments on operations upon the heart and great vessels.     

SOME RECENT ADVANCES IN THORACIC SURGERY

In this brief presentation of some recent advances in thoracic surgery a number of miscellaneous topics which deserve consideration at this time are discussed. Among these are acidosis during anesthesia for thoracic operations, the problem of esophagitis in relation to surgery, recent improvements and reorientations in pulmonary operations, and some comments on operations upon the heart and great vessels.     

Effects of handling and electrofishing on plasma glucose and whole blood lactate of Leuciscus cephalus

Chub Leuciscus cephalus exposed to simulated pulsed direct current electrofishing operations exhibited rapid elevations in plasma glucose and blood lactate levels. Plasma glucose levels were significantly higher 0·5 h after simulated electrofishing operations, and peaked 2 h after treatment. Glucose levels remained high for up to 4 h. No changes in plasma glucose were evident following handling. Simulated electrofishing operations and handling induced an immediate lactacidosis in chub. Initial responses to both treatments were similar except that blood lactate was significantly higher in fish exposed to simulated electrofishing operations than in handled fish 5 and 15 min after treatment. Blood lactate remained elevated in fish exposed to simulated electrofishing operations for 2 h, while blood lactate of handled fish returned to levels similar to those in the control fish within 0·5 h post‐treatment.     

DNA databases

This paper presents DNA algorithms for five relational algebra database operations, selection, projection, union, set difference, and Cartesian product on so-called DNA databases. A DNA database is a database where data records are encoded as DNA strands. The five operations mentioned before are fundamental in the field of databases and perform most of the data retrieval operations on current databases.     

Socioeconomic variations in the use of common surgical operations.

The surgical experience of a sample of people aged 40-64 randomly selected from general practice lists was elicited by means of a postal questionnaire and the results examined in relation to two indicators of socioeconomic status. Eighty per cent of the sample had had one or more surgical operations and women had a higher mean number of operations than men. Those in the more advantaged groups had a higher mean number of operations than those in the less advantaged groups. This difference was, however, mainly accounted for by operations carried out in childhood before the establishment of the National Health Service and by private sector surgery.     

Quantifying life cycle inventories of agricultural field operations by considering different operational parameters

Purpose

The ability to estimate fuel and lubricant consumption as well as depreciated weight of agricultural machinery used for field operations is very useful for energy and environmental analyses. In this study, life cycle inventory data of agricultural field operations were established by considering different parameters of such operations.

Methods

Agricultural operations considered in this study include tillage, cultivation, planting, harvesting and post-harvest operations. For these operations, the fuel and lubricant consumption as well as depreciated weight of tractors, combine harvesters and agricultural implements was estimated by considering different operational parameters such as tractor power, field condition, depth of operation, soil condition, tractor type, operational capacity of machine, width of operation and speed. Technical standards were used to estimate different types of power required for most agricultural operations (drawbar power, rotary power and motion power). The standards were then used to evaluate the variability of the fuel and lubricant consumption as well as depreciated weight of the implements by varying the aforementioned parameters.

Results and discussion

The results were compared to those that can be calculated with other approaches for life cycle inventory analysis of agricultural operations. Such comparison indicates that by using different parameters, representing the diverse local conditions of different field operations, a great variability of the results is obtained. For instance, diesel fuel consumption of tillage operations ranges from 12.6 to 76.0 L ha^?1, with an average of 34.15 L ha^?1 and standard deviation of 11.7 L ha^?1. Such representativeness of the different conditions of each field operation cannot be modelled with other tools or via the use of standard LCI datasheets.

Conclusions

The final result of this study is a novel approach for the life cycle inventory analysis of agricultural operations, in terms of fuel and lubricant consumption and of depreciated weight of the machines, which are estimated by simply selecting the operational parameters which best represent the effect of local conditions.