Important Cost Components Research Articles

The Effect of Standard Metabolic Rate on Egg Production in the Acridid Grasshopper,Xanthippus corallipes

SYNOPSIS. Models of energy budgets often allocate energy between the broad categories of maintenance, growth, and reproduction. An important component of maintenance costs is standard metabolic rate, which is partially determined by body temperature. The relationship between thermoregulation, standard metabolism, and egg production was investigated in adult females of the acridid grasshopper Xanthippus corallipes from six populations along an elevation gradient. Individuals thermoregulate and maintain stable afternoon body temperatures which correlate negatively with elevation. Standard metabolic rates were calculated at each population's afternoon body temperature. These rates were then used to investigate the effect of variation in standard metabolic rate on egg production. Because of the pervasive effect of mass on standard metabolic rate and egg number, the variables were log-transformed. The effect of mass was removed by regression analyses, and residuals were calculated. An analysis of the residuals revealed that intermediate values of field standard metabolic rate correlate with high egg production, suggesting stabilizing selection on standard metabolic rate.

Optimum junction point location and inventory levels in serial hybrid push/pull production systems

The choice of a production philosophy by a manufacturing company is important. Costs for holding inventory and costs for missing due-dates on customer orders are key components of overall profitability. In this paper, an optimization model of a new, yet simple, kind of horizontally integrated push/pull hybrid production system (HIHPS) is formulated that resolves the tradeoff between these two important cost components. At optimum, it will suggest either an allpush, all-pull, or a mixed operation configuration. A mixed system would be comprised of push stations followed by a cache of semi-finished product (SFP), followed by pull stations. An exact analytical solution of HIHPS is derived for the automated (low variability) case. A modification of the simulated annealing algorithm is presented to conduct the optimization search. Results of a case study are used to demonstrate the methodology and validate the model's predictions.

Costs of water treatment due to diminished water quality: A case study in Texas

The cost of municipal water treatment due to diminished water quality represents an important component of the societal costs of water pollution. Here the chemical costs of municipal water treatment are expressed as a function of raw surface water quality. Data are used for a 3‐year period for 12 water treatment plants in Texas. Results show that when regional raw water contamination is present, the chemical cost of water treatment is increased by $95 per million gallons (per 3785 m3) from a base of $75. A 1% increase in turbidity is shown to increase chemical costs by 0.25%.

Human productivity in space and systems costs

Human productivity during assembly operations in-orbit is dependent on limits set by fatigue, metabolic rates, learning, and assembly techniques. In order to quantify these effects, tests were conducted in the NASA MSFC Neutral Buoyancy Simulator, in the NASA KC-135 in parabolic flight, and in space with the EASE program during the Shuttle Atlantis mission 61-B. A separate program attempted to relate productivity to system costs. Because of the surprisingly high productivity which had been demonstrated in orbit, it was shown that assembly operations would have only a small effect on system costs at the present level of launch costs. The results of these continuing studies have been reported in a recent paper(1). They will be briefly summarized here and the results updated to include additional cost elements and to examine the effects of reductions in transportation costs, resulting from advances in technology and from increased demand, on system costs. It is shown that, as launch costs are reduced, the assembly costs could become an increasingly important component of the total system costs.

Resource implications of head injuries on an acute surgical unit.

Head injuries are expensive and demanding in terms of resources. In the UK, most are cared for outside neurosurgical centres. In the absence of specialist rehabilitation services, patients with on-going disability add to those admitted for observation and treatment on acute surgical wards. We audited the workload pattern and financial implications related to head injuries on a general surgical unit in a central London teaching hospital. Data collected prospectively at the time of admission and derived from departmental computerized information systems included clinical outcome, hospital stay and its relationship to severity of injury and other factors. Ward, departmental (accident and emergency (A & E), intensive therapy unit (ITU), radiology, and theatre) and neurosurgical referral costs were derived. Long-term social and rehabilitation costs were not calculated. Over a 6 month period 899 patients with head injuries were treated in the A & E department, of whom 156 were admitted. Of the admitted patients 68% were classified as minor; 22% as moderate; and 10% as severe head injuries. Fifty-one per cent of adult admissions were intoxicated by alcohol. Prolonged hospital stay was related to age, severity of head injury, mechanism of injury, associated injuries and preexisting neuropsychiatric conditions (including alcoholism). Six patients died. The direct cost of these head injuries patients was estimated at 173,500 pounds, during which time they occupied 7.6% of our unit's adult inpatient capacity. Twenty-four hour observation of 76 patients with minor head injuries contributed 9700 pounds (5.6%) to this figure. Associated extracranial injuries cost a further 46,500 pounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Strikes in the Community: addressing some early questions

In post–1992 Europe, capital will tend to flow to areas of lowest unit output cost. Difference in the quality of labour-management relations, here proxied by strike activity, could be an important component of such costs. The performance of strike models for EC member states is examined, paying particular attention to the evidence for reaction equality to macroeconomic stimuli and for the existence of ‘strike waves’. Both hypotheses are rejected, meaning firstly, that there is no justification for datapooling but, secondly, that member states are free to pursue policies to improve their industrial relations environments without fear they will be undermined by developments elsewhere.

A COMBINED OPTIMIZATION AND SIMULATION APPROACH FOR DESIGNING AUTOMATED STORAGE/RETRIEVAL SYSTEMS

The study of Automated Storage/Retrieval Systems (AS/RS) in warehouses has developed along two main lines: One seeks to minimize total cost of an AS/RS, while the other explores the dynamic behavior of such a system. This study addressing the two issues simultaneously, obtains design parameters for a system that complies with desired levels of performance. To this end, a heuristic recursive optimization/simulation procedure is developed. It is also assumed that the number of stacker cranes (an important cost component of AS/RS) can be less than or equal to the number of aisles. The proposed procedure was applied to several situations, and converged within a few iterations.

Effects of Turning Forging Steels Which Lead to Discontinuous Cutting Conditions

An important component of the total production costs of forged parts are the costs for finish turning. During the last few years near-net - shape technology has been advanced, so that the realizable accuracy by chipless forming has been enhanced and cutting operations are necessary at connection surfaces. This can lead to discontinuous cutting processes caused by the varying depth of cut or interrupted cut. Results obtained from turning tests with continuous cutting cannot be used as a base for the machining of those forged parts. For a reduction of production costs of near-net-shape forged parts further investigations on machinability are necessary by adapted testing methods.

A mixed-integer programming approach to the machine loading and process planning problem in a process layout environment

SUMMARY A mixed-integer programming (MIP) model for the machine loading and process planning problem has been developed for a process layout environment. This model relaxes the most commonly used assumption that each operation can be assigned to only one machine. In this model, the most important production cost components: machining cost, material handling (MH) cost, setup cost and machine idle cost are considered. In addition, by assigning penalty cost for long makespans, the optimal process routes for each part and optimal load for each machine in terms of minimum production cost can be obtained with lower makespan. An example problem is solved, followed by discussions with regard to the impact of batch splitting, setup cost and demand change on optimal solution.

Machinability of forged steels in interrupted cutting

An important component of the production costs of forged parts is the cost resulting from the cutting process: the improvement of the machinability of the workpiece material leads to a reduction of this cost. Machinability tests are carried out often by continuous cutting, but results obtained under these conditions cannot be transferred to interrupted cutting. However, the machining of drop-forged parts very often includes interrupted cutting, for example during milling and turning. In this paper the two procedures are examined and compared under similar conditions, with the aim of enabling a transfer of machinability test results.

Economic aspects of cervical cancer screening

The results of a cost-effectiveness analysis of cervical cancer screening in The Netherlands are reported, emphasizing the analysis of the costs of screening and consequent diagnosis and treatment. Many organized screening policies are evaluated, differing in age-range and interval between screens. The cost estimates are based on organization charts, file studies and tariffs. The costs of screening itself are by far the most important cost component. Screening increases the costs of diagnosis. Costs for primary treatment only rise for large screening policies. Screening causes savings in costs of terminal treatment, but these are small compared with the costs of screening. The costs per life-year gained for the most efficient policies amount to DFL 24,000 for the policy with 7 invitations per woman in a lifetime and rise considerably in case of more than 10 invitations. Cervical cancer screening appears to be less cost-effective than breast cancer screening, but compared with other services the results are comparatively good. Implementing one of the efficient organized screening policies and discouraging spontaneous screening beyond that schedule leads to considerable savings. Moreover, many organized policies which are not efficient are still superior to spontaneous screening.

The optimization of hybrid energy conversion systems using the dynamic programming model—Rapsody

The paper describes a stochastic, dynamic programming model, RAPSODY, which is designed to analyse and determine optimal operating strategies for a hybrid electricity generating system comprising up to three diesel sets with optional battery storage and augmented by variable wind or photo-voltaic power. The model takes capital, operating and maintenance, and fuel costs into account to assess the optimal operating strategy for the auxiliary and to calculate the average daily cost of satisfying an electrical load profile which may also contain a stochastic element. In doing so, the decreased fuel efficiency and lifetime of the diesel set as it is operated below full capacity is explicitly taken into consideration as is a further important cost component attributable to switching on. The model is provided with an efficient optimizing routine which allows the user to obtain optimal component sizes for a particular load profile and wind or solar resource. An example is given in which a hybrid wind power system incorporating battery storage and an auxiliary diesel generator is optimized. For the case studied, the auxiliary switching cost and the shape of its operating cost function were important in defining the optimal operating strategy which was a significant factor in minimizing generating costs.

Observations on the use of a long-acting oxytetracycline for in-contact prophylaxis of undifferentiated bovine respiratory disease in feedlot steers under Canadian conditions

Respiratory diseases are the most common causes of mortality in the feedlot. Often, mortality alone is not the most important component of health costs but added to this must be the cost of morbidity (treatments, prophylaxis and reduced feed efficiency). Traditionally, the cattle marketing system in Canada mixes cattle with different levels of stress, different micro-organisms in number and amount and different nutritional backgrounds. Unless significant changes in patterns of cattle marketing occur, the incidence of respiratory disease will still remain the feedlot industry's most costly health problem. The purpose of this project was to study an outbreak of naturally occurring undifferentiated respiratory disease in feedlot steers under feedlot management conditions which was curtailed by using the principle of mass individual treatment.

A rapid heuristic algorithm for the approximate solution of the traveling salesman problem

In this article we put forward a simple algorithm for the rapid approximate solution of the single terminal traveling salesman problem. The focus of application of the algorithm is an environment wherein the cost of computation is an important component of the total cost of generating and using a solution. A comparison of several heuristic algorithms is made using three classical problems. The cost of computing and using these solutions is shown to be dependent on the scale of measurement of the problem. Our algorithm is shown to be least costly when computation cost dominates the total cost. The results also give some indications as to when more accurate algorithms should be used.

Impact of 'Prescription Audit & Feedback' on Pattern of Prophylactic Antimicrobials in Cesarean Section: a Cost Reduction Perspective

Cesarean section is a common operative procedure in obstetrics. Prophylactic uses of antimicrobials in different categories of surgeries are irrational in general, which is also observed in cesarean section. Cost of antimicrobial imposes an enormous burden on the patient or the system and considered as an important cost component of cesarean section.A cross-sectional study was conducted from August 2002 to July 2003 in 8 units of the Departments of Gynecology & Obstetrics of Bangabandhu Sheikh Mujib Medical University, Sir Salimullah Medical College & Mitford Hospital and Sher-E-Bangla Medical College & Hospital. Basleline data were collected both retrospective and prospective. After collection of baseline data, result of prescription audit was disseminated among the prescribers through face-to-face discussion and workshop in one unit with particular emphasis on cost perspective.Quality of record keeping was found satisfactory as there was no significant difference between prospective and retrospective data. Seven different treatment plans were used for prophylaxis. Highest patients were treated with plan-A (46.46%), followed by plan-B (35.42%) and lowest with the single dose, plan-F (1.04%). Average duration of antimicrobial therapy was highest in plan-D (10.00 ± 1.55 days) and lowest in plan-F (6.40 ± 0.40). Average cost of antimicrobial during hospital stay was highest in plan-B (1497.25 ± 18.80 taka) and lowest in plan-F (90.00 ± 0.00 taka). The difference between percentages of patients with different condition of the amniotic membrane receiving same treatment plan was not statistically significant. The difference in patients receiving same treatment plan for different indications was not statistically significant except in treatment plan-F, where patients with relative indications received plan-F significantly higher (p < 0.001) than patients presented with absolute indications. Significant relationship was observed with economic status of patient and choice of treatment plan. The average duration of antimicrobial therapy of patients having infection after cesarean section, was 12.16 ± 0.42 days and those of patients having no infection after cesarean section, was 7.19 ± 0.08 days and this difference was highly significant (p < 0.001).After intervention with 'prescription audit & feedback', the expensive treatment plan, plan B reduced from 93.33% to 0.00% and the difference was highly significant (p<0.001). 'Prescription audit & feedback' was found to be effective in reducing the infection rate from 16.67% to 0.00% and the difference was significant (p<0.05). Average duration of antimicrobial therapy in hospital was reduced from 8.60 ± 0.22 days to 7.62 ± 0.06 days and the difference was significant (p<0.05). Average cost of antimicrobial therapy was reduced from 1693.11 ± 30.82 taka to 511.00 ± 2.35 taka and the difference was highly significant (p<0.001).The initial success of 'prescription audit & feedback' in improving cost-effective prescribing generated opportunity for partnership between pharmacologist and clinicians in the field of promotion of rational prescribing. The cost-effectiveness of 'prescription audit & feedback' and its' reproducibility in other clinical situations should be investigated by the future researchers to make this particular intervention acceptable to the policy makers. DOI: 10.3329/bjpp.v23i1.5723Bangladesh J Physiol Pharmacol 2007; 23(1&2) : 1-9