Individual Time Periods Research Articles

Individual Time Period Analyses over the GATE Ship Array

Abstract Diagnostic moisture and dry static energy budgets for the GATE A/B-scale area are performed for individual time periods using rawinsonde and satellite data. The data are sufficiently accurate to permit quantitative analysis of that area with 3–6 h time resolution. Each budget is used to estimate the net condensation rate for every time period. The budget condensation rates slightly exceed radar rainfall estimates for the GATE master array and the radar values lag the budget condensation by 4–6 h during major rainfall episodes. Storage of liquid water and unsampled vapor in clouds can account for a large portion of the observed lag. The present results indicate that observed 3–6 h lags between, low-level mass convergence and echo growth during GATE result primarily from the lag between condensation and precipitation during convective system evolution. The release of latent heat in a tropical convective system appears to be closely related to the instantaneous mass convergence below 700 mb. Budget-...

The cyclic separation scheduling problem

AbstractThis paper deals with the problem of scheduling items (tasks, employees, equipment, etc.) over a finite time horizon so as to minimize total cost expenditures while maintaining a predefined separation between certain items. The problem is cyclic, because the same schedule will be repeated over several consecutive time periods of equal length. Thus, requirements are present to maintain the separation of items not only within the individual time periods considered, but also between items in adjoining periods. A special purpose branch‐and‐bound algorithm is developed to solve this scheduling problem by taking advantage of its cyclic nature. Computational results are given.

A simulation model for operating a multipurpose multireservoir system

This paper describes a mathematical model used for assessing alternative policies of operation for the Trent River system in Ontario, Canada. The Trent basin is characterized by numerous reservoirs (48 were represented in the model), each with a control structure(s) in its outlet channel(s). The reservoir system is used for flood control, water supply, hydropower, and augmenting flows through the canal system during the summer period. The need for assessing alternative policies arose from growing conflicts in recent years over satisfying all of the many water‐based needs of the basin. To aid in assessing the impact of alternative policies, a simulation model was developed and applied. Every reservoir was subdivided into five storage zones (which were variable in a temporal sense). A time‐based rule curve was also prescribed to represent ideal reservoir operation. Ranges were prescribed for channel flows, which were dependent on water‐based needs. The underlying concept of the model was the functional (or mathematical) representation of the chief operator's perception of ‘Optimum’ operation and the derivation of this solution using a nested optimization submodel. ‘Penalty coefficients’ were assigned to those variables which represented deviations from ideal conditions. Different operational policies were simulated by altering relative values of these coefficients. The development and use of the model were simplified by representing the entire reservoir system in ‘capacitated network’ form and deriving optimum solutions for individual time periods with the ‘out‐of‐kilter’ algorithm. Besides being computationally efficient this algorithm simplified model development and permitted flexibility in readily using the model for a wide range of reservoir configurations and operating policies.

The effects of changes in dietary protein and water availability on urinary nitrogen compounds in the rooster, Gallus domesticus—II. Diurnal patterns in urine flow rates, and urinary uric acid and ammonia concentrations

1. 1. Excretory parameters of roosters exhibit diurnal patterns of variation that are altered by changes in dietary protein, water availability and time of feeding. Patterns of urine flow rate are influenced most by changes in water availability, while patterns of urinary uric acid and ammonia concentration are altered most by changes in dietary protein content. 2. 2. Urinary flow rates and uric acid concentrations are inversely related for individual time periods. 3. 3. Changes in feeding time altered some excretory parameters but did not result in a predictable pattern of changes.

The changes in the titre of the sugar beet yellows virus in sugar beet leaves in the course of the vegetation period

Using the quantitative serological method of double diffusion in agar, the amount of sugar beet yellows virus in the leaves of sugar beet was investigated and the possibility of an accurate serological analysis was examined at certain time periods in the course of vegetation. In sugar beets infected artificially at the beginning of the vegetation period the increase of the titre has a fluctuating course at first. In August, after the intensive growth of plants is over, the virus content maintains on a relatively high degree, increasing further toward the end of vegetation. For a reliable virus analysis the sap can be diluted approximately in the ratio 1/128. The table presented enables one to determine the probable accuracy of the serological analysis at the individual time periods during the vegetation of sugar beet.

An Algorithm for Project (Job) Sequencing with Resource Constraints

This paper treats the problem of project (or machine) scheduling with resource constraints to achieve minimum total duration time as a disjunctive graph. The prospective advantage of this approach is the elimination of the need to consider individual time periods over the program horizon; a feasibility check determines whether the resource constraints can be met by any particular network representation of the project. The paper gives an algorithm that uses partial enumeration for what is essentially a mixed integer program. The algorithm employs a maximum-flow computation as a check for feasibility with respect to available resources.

EFFECT OF FOUR CENTRALLY ACTING DRUGS ON HANDWRITING

Writing is a motor act which is acquired early in life and the performance thereafter remains stable over long periods of time in adult individuals. Successive samples are, thus unlikely to be affected by further practice (1). At the same time, handwriting, being a complex motor act requiring fine co-ordination should be more sensitive to the effects of psychoactive agents than simple skills (2). Further, repeated samples of handwriting can be obtained easily and quickly. In the present investigation effects of four psychoactive agents, caffeine, chlorpromazinc, methamphetamine and phenobarbitone, on handwriting have been studied. A preliminary report of the work has appeared (3).

DETERMINATION OF THE VOLUME OF THE EXTRACELLULAR FLUID OF THE BODY WITH RADIOACTIVE SODIUM

A method for measuring the volume of fluid available for the distribution of sodium (sodium space) by the use of its radioactive isotope (Na(24)) has been described and the accuracy of the method has been discussed. Simultaneous determinations of the plasma volume by means of the blue dye T-1824 and the volume of the extracellular fluid by employing radiosodium and sodium thiocyanate have been made in normal subjects. Repeated measurements were made at varying periods of time in the same individuals. In order to establish the rate of diffusion equilibrium for the radioactive isotope of sodium and thiocyanate between serum and serous effusions, simultaneous samples of both were obtained at varying intervals after the intravenous injection of these substances. Since evidence in the literature indicates that there is an excess of sodium mainly limited to bone, which cannot be attributed to the extracellular phase, experiments on dogs and man were so devised that the ratio of tissue concentration to plasma concentration for radiosodium and chemically determined chloride could be calculated. The following conclusions may be drawn from the results of this investigation: 1. Radiosodium after intravenous administration spreads rapidly during the first 3 hours from the plasma into a volume of fluid which represents approximately 25 per cent of the body weight of man. Thereafter for 6 hours it diffuses more slowly into certain tissue spaces-the central nervous system and probably the skeleton. The plasma volume and interstitial fluid represent 15 and 85 per cent of the sodium space respectively. 2. Diffusion equilibrium for both radiosodium and thiocyanate is not established between serum and transudates in edematous patients until from 9 to 12 hours after the intravenous injection of these substances. 3. Until more complete information is available, it is concluded that unless the difference between repeated observations on the same individual exceeds +/-1.38 liters there is no significant change in the sodium space providing that the activity of the standard and serum samples are in the range of 40 counts per minute per milliliter with the counting apparatus used. As the activity of the samples increases, the error becomes less because there is no correlation between the magnitude of the error and the magnitude of the activity. 4. Climatic conditions produce no significant changes in the volume of the blood or extracellular fluid. 5. In the dog, following the intravenous injection of radiosodium, the concentration of the isotope in bone reaches its maximum rapidly (3 hours). The extra sodium in the skeleton of dog is equal to about (1/4) of the total counts in the body, assuming that the chloride space of bone represents its extracellular volume. Similar amounts of excess sodium are found in the skeleton of man 12 hours after the administration of Na(24). 6. Correction of the sodium space of man for the excess sodium reduced the average value by 3.7 liters or 18.9 per cent. The average corrected volume for the normal subjects 6 hours after the injection is 15.9 liters or 21.1 per cent of the body weight compared with the thiocyanate space of 17.7 liters, representing 23.5 per cent of the body weight. 7. The most useful method for calculating the sodium space from the data obtained after intravenous administration of radiosodium is as follows: See PDF for Equation This space exceeds the volume of extracellular fluid by the amount of excess sodium in the body that cannot be attributed to the extracellular phase. 8. While neither the thiocyanate method nor the radiosodium method gives precise estimates of the extracellular fluid, the error is of the same order of magnitude in both. For clinical use, the thiocyanate method is superior because of the ready availability of the substance, and the apparatus required.