Optimal Length Of Time Research Articles

The Impact of IMPACT: An Assessment of the Effectiveness of a Jail-Based Treatment Program

This study examined the effects of a drug treatment program in Chicago's Cook County Jail (CCJ). The program, known as the Integrated Multiphase Program of Assessment and Comprehensive Treatment (IMPACT), involves three agencies and is based on the general model of a modified therapeutic community. IMPACT significantly reduced rearrest rates and delayed time-to-rearrest for program participants. Outcomes improved as length of stay in the program increased up to 150 days, after which there were no further reductions in recidivism. In addition, community treatment significantly reduced rearrest rates even for inmates who stayed an optimal length of time in the program.

THE EVOLUTION OF FLORAL LONGEVITY: RESOURCE ALLOCATION TO MAINTENANCE VERSUS CONSTRUCTION OF REPEATED PARTS IN MODULAR ORGANISMS.

The component parts of modular organisms often show interspecific variation in their longevity. In plants, the flower is an example of such a structure. Models are developed in this paper to predict optimal floral longevity (the optimal length of time that flowers should remain open and functional) under a variety of conditions. A tradeoff involving allocation of resources to floral construction versus floral maintenance is assumed. The main model variables are the rate at which pollen and seed fitness accrue over time (fitness-accrual rates) and the daily cost of maintaining an existing flower relative to the cost of constructing a new one (floral maintenance cost). Long-lived flowers are selected when fitness-accrual rates and floral maintenance costs are low, whereas short-lived flowers are selected when fitness-accrual rates and floral maintenance costs are high. Dichogamy favors longer-lived flowers relative to homogamy, whereas nonindependence among flowers in their attractiveness to pollinators (attraction to flower clusters) selects for shorter-lived flowers. Reduction in floral maintenance costs later on in the flower's life favors longer-lived flowers. Observations on the dissemination and receipt of pollen in individual flowers over time, together with measurements of corolla respiration and nectar sugar production rate are required to test the model quantitatively. The parameters important to the evolution of optimal floral longevity (i.e., maintenance and construction costs, and fitness-accrual rates) may be general features of evolution of optimal longevities of other repeated structures.

Education programmes for fibromyalgia patients: description and evaluation

A firm theoretical basis for patient education in rheumatic disease care has been built up over the past 10 to 15 years. Education in self-management has enabled patients to control symptoms and become partners in care with their health providers. Education for fibromyalgia patients has come to the foreground during the last 5 years as health professionals have come to understand the syndrome better and recognize the role that stress plays in the exacerbation of symptoms. A few controlled trials of various strategies, such as aerobic conditioning and cognitive-behavioural techniques, have been reported recently. All have shown significant benefits to patients with fibromyalgia. Only one controlled trial has studied the effects of a self-management education programme alone. The results of this programme were positive. Self-efficacy and life quality were enhanced. This programme and an uncontrolled programme that integrated many strategies have shown some of the first positive long-term indications that patients who are treated intensively for even a short time can continue to improve as they practice self-management techniques. There is still a need for further documentation of non-drug treatment strategies and especially further research into who is helped by which strategies, the optimal length of time for a programme, and the need for ongoing treatment.

Inhibition of neutrophil adhesion does not prevent ischemic spinal cord injury

Paraplegia may occur after transient aortic occlusion as a consequence of primary ischemia to the spinal cord or injury during the reperfusion period. In animal models of ischemia/reperfusion there is evidence that reperfusion injury may be modulated partially by neutrophils. The efficacy of the neutrophil adherence blocking murine monoclonal antibody (MAb 60.3) was assessed in spinal cord ischemia/reperfusion in rabbits. Spinal cord ischemia was accomplished by balloon catheter occlusion of the infrarenal aorta. Neurologic assessment was graded as normal, partial neurologic deficit, or complete paralysis. Electrophysiologic monitoring with somatosensory evoked potentials was used to determine the optimal length of time of occlusion. Animals were treated randomly with 2 mg/kg of intravenous MAb 60.3 (n = 8) or saline solution (n = 9) with the investigator unaware of treatment. Mean occlusion times were no different between groups (control, 32.7 ± 3.6 minutes versus MAb, 32.4 ± 6.0 minutes). Five (55%) saline-treated and four (50%) MAb 60.3-treated animals became paraplegic. Animals with initial paraparesis all progressed to flaccid paraplegia within 24 hours. We conclude that spinal cord injury after transient aortic occlusion is independent of the CD11 / CD18 glycoprotein complex of the neutrophil. Injury in this setting may occur during ischemia and thus may not be dependent on neutrophils or reperfusion.

Predictive Factors of Long-term Compliance With Nasal Continuous Positive Airway Pressure Treatment in Sleep Apnea Syndrome

The long-term acceptability of treatment with nasal continuous positive airway pressure (CPAP) was studied prospectively in 44 patients with obstructive sleep apnea syndrome. At 14 months on the average after starting treatment with CPAP, 30 patients (68 percent) were found to be compliant (characterized by use of the apparatus every night throughout the night, for more than 5 h per night). The daily use of nasal CPAP was significantly correlated to the initial apnea/hypopnea index (p = 0.013; r = 0.37), as well as to the percentage of light sleep (p = 0.045; r = 0.30) and slow-wave sleep (p = 0.037; r = -0.31) during the initial polygraphic recording. We found a strong correlation between the daily use of nasal CPAP and the difference in the apnea/hypopnea index (p = 0.025; r = -0.34), the difference in mean oxygen saturation during sleep (p = 0.013; r = 0.38), and the difference in hypersomnia scores (p = 0.006; r = -0.40) obtained before and after treatment by nasal CPAP. Thus, patients used CPAP much more if they had an initial significant clinical handicap and if they were aware of the beneficial effects of CPAP. Under these conditions, patients tended to use the apparatus for the optimal length of time, regardless of the side effects linked to the treatment. This ensured efficacy and the maintenance of good compliance. This study confirms the importance of supervision of the time counter, as well as regular encouragement of patients to use the treatment as long as possible each night, in order to extract a maximum benefit from treatment by nasal CPAP.

OPTIMUM CYCLE TIME IN SEMI-BATCH ULTRAFILTRATION SYSTEMS

Abstract Based on the goal of maximum permeate production rate, a simple and practical method is proposed lo allow operators to determine when to stop a semi-batch ultrafiltration system and initiate the clean-in-place procedure. The method does not need previous modeling or knowledge of the way in which the permeate flux decreases with time. Simple but adequate instrumentation is required for on-line determination of the optimal length of time that the system has to operate. Although the analysis is made assuming characteristics very frequently found in the clarification or fruit juices, the application of the method could be extended to other types of operations where progressive and significant fouling obligates to frequent nonproductive cleaning periods to keep the economy of the production level.

Economics of ocean culture of giant clams, Tridacna gigas: internal rate of return analysis

The paper estimates the internal rate of return of investment in a giant clam farm involved in the ocean phase of mariculture as a function of the period of ocean growout of Tridacna gigas. The ocean farm is assumed each year to place 100 000 seed clams of approximately 1 year of age. The optimal length of time to hold them depends on the farm-gate price of clam meat and is estimated to be 11 years when they are sold at $A5 per kg. This yields an estimated internal rate of return of 18.0% and maximises the net present value or capitalised value of the farm. If 40% drip loss occurs in the meat the internal rate of return is 11.25% and the optimal period to hold batches of clams is 14 years.

Inflation, the Payments Period and the Demand for Money

Part I of this paper develops a model of economic response to inflation. Sections A, B, and C consider the maximizing behavior of employers and employees in the context of a steady rate of inflation. Since the rate of price change can be translated into an effective cost of holding money, a higher rate provides increased incentive for economizing on cash balances. Two methods of economizing are considered: first, (Sections A and B), reductions of the time interval between various types of payments (increases in and, second (Section C), decreases in the fraction of transactions. With a given fraction of monetized transactions, the selection of the optimal length of time between (wage and other types of) payments involves a tradeoff of the inventory type. Given some fixed (real) cost of making payments, a higher rate of price change reduces the optimalpayment interval (increases velocity) and produces a corresponding reduction in average real holdings. The demand-for-money function which is implied by optimal-payments period selection approaches an inflation-rate elasticity of 1/2 as the rate of inflation becomes large (relative to real rates of return in the economy). However, this formulation assumes that the fraction of monetized transactions is unaffected by changes in the inflation rate. In fact, money may be viewed as a medium which provides certain transactions benefits (in terms of physical convenience, general acceptability, et cetera) in comparison with alternative media. At a higher rate of price change, the cost of retaining as a payments medium is increased (relative to

Inflation, the Payments Period, and the Demand for Money

Part I of this paper develops a model of economic response to inflation. Sections A, B, and C consider the maximizing behavior of employers and employees in the context of a steady rate of inflation. Since the rate of price change can be translated into an effective cost of holding money, a higher rate provides increased incentive for economizing on cash balances. Two methods of economizing are considered: first, (Sections A and B), reductions of the time interval between various types of payments (increases in and, second (Section C), decreases in the fraction of transactions. With a given fraction of monetized transactions, the selection of the optimal length of time between (wage and other types of) payments involves a tradeoff of the inventory type. Given some fixed (real) cost of making payments, a higher rate of price change reduces the optimalpayment interval (increases velocity) and produces a corresponding reduction in average real holdings. The demand-for-money function which is implied by optimal-payments period selection approaches an inflation-rate elasticity of 1/2 as the rate of inflation becomes large (relative to real rates of return in the economy). However, this formulation assumes that the fraction of monetized transactions is unaffected by changes in the inflation rate. In fact, money may be viewed as a medium which provides certain transactions benefits (in terms of physical convenience, general acceptability, et cetera) in comparison with alternative media. At a higher rate of price change, the cost of retaining as a payments medium is increased (relative to

EFFECT OF RETROBULBAR ANESTHESIA UPON INTRAOCULAR PRESSURE. PRELIMINARY REPORT ON ITS IMPORTANCE IN CATARACT SURGERY.

The application of digital pressure to the eye and orbit following retrobulbar injection of local anesthetics prior to cataract surgery has become a routine procedure to many ophthalmic surgeons. The studies of Kirsch 1,2 established the efficacy of this maneuver and suggested that the optimal length of time for the application of digital pressure is five minutes. Possibly because of the very fact that this maneuver has become routine, it is often assumed without reservation that ocular hypotony has occurred, unless there is visible evidence of retrobulbar hemorrhage. The present study of ocular tension following retrobulbar injection of an anesthetic and during the period of digital pressure to the orbit clearly indicates that such an assumption is unwarranted. This evidence is so conclusive that it is felt that an incision in cataract surgery should never be made, even after five minutes of digital pressure, until hypotony has been proven by

Further studies on the use of digital pressure in cataract surgery. I. Optimal length of time for applications of digital pressure.

In a previous communication 1 it was shown that application of five minutes of digital pressure after the retrobulbar injection, following the ideas of Atkinson 2-5 and Chandler, 6 constitutes a very definite clinical safeguard against the loss of vitreous during cataract surgery. It was further shown that, thus far, the best experimental criterion for judging this safeguarding action of digital pressure lay in the depth and duration of the accompanying ocular hypotony. It has accordingly now become desirable to determine the optimal length of time for application of digital pressure; for, in an operation already considerably lengthened by the use of modern corneoscleral suture techniques, it becomes important to know if the same safety may be achieved in less than five minutes or, conversely, if even greater safety is induced by more than five minutes of digital pressure. Materials and Methods The material for this study consisted of 60