Experimental scheduling

Depending on the objective of a study the time and duration of calorimetric measurements have to be defined typical measurements in calorimetric chambers are about a full day or even several full days. Experimentors often use comparative methods to measure physiological, pharmacological or dietetic values. 

Daily energy expenditure can be separated into the basal metabolic rate (BMR), the postprandial thermogenesis (ppTh), also called dietary induced thermogenesis (DIT) and the energy needed for locomotor activity (LA). Locomotor 

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TABLE 82.2 Experimental Schedule for Human Performance Capacity Test Battery (HPCTB)... 

The heat content of the chamber depends under well-defined conditions only on chamber temperature. This is, however, not always balanced with the air temperature in the chamber. If the chamber temperature remains constant the heat content can be assumed to be constant, especially if the experimental schedule is comparable for different measurements. This constant heat content is than added to resulting in the nonevaporative heat loss of the subject. Most experimentors did so in the past however, there are some papers dealing with heat storage compensation in the calorimetric chamber [13,15]... 

If treatment of the experimental data used by Ehrlich (27), by Ageev, Ionov, and Ustinov (28), and by Lapujoulade (66) is employed, a mere empirical knowledge of the time-temperature dependence is sufficient (see Section I). Most authors, however, use an analytical approach to the treatment of the desorption data, where a simple analytical expression of the time-temperature function is essential. In such a case, the following two schedules are employed due to their feasibility and relative simplicity from the mathematical point of view (i) The temperature T of the adsorbent increases linearly with time t ... 

Its main features are given by the use of a stream of inert carrier gas which percolates through a bed of an adsorbent covered with adsorbate and heated in a defined way. The desorbed gas is carried off to a detector under conditions of no appreciable back-diffusion. This means that the actual concentration of the desorbed species in the bed is reproduced in the detector after a time lag which depends on the flow velocity and the distance. The theory of this method has been developed for a linear heating schedule, first-order desorption kinetics, no adsorbable component in the entering carrier gas (Pa = 0), and the Langmuir concept, and has already been reviewed (48, 49) so that it will not be dealt with here. An analysis of how closely the actual experimental conditions meet the idealized model is not available. 

Long time constants in the system and zone-to-zone interaction of the heaters complicated the controller design and tuning. The time available for experimental measurements was limited by the schedule of other experimental work to be performed by the extruder. The classic step response methods of tuning controllers would take on the order of hours to perform, and frequently disturbances in the polymer feed or in the ambient room conditions would invalidate the test. Consequently, a mathematical rather than an empirical approach was desirable. 

Surface residues of DDT on apples resulting from experimental applications applied in schedules comparable to commercial usage ranged from less than 0.5 to 2.0 p.p.m. at harvest. Schedules of application involving higher spray concentrations and greater frequency of application than are at present required in commercial practice resulted in most cases in residues of less than 7 p.p.m. Typical harvest residues are presented in Table I. 

On pears, experimental applications of DDT applied in commercial schedules resulted in surface residues ranging from less than 0.5 to approximately 3 p.p.m. Typical harvest residues are shown in Table II. 

Spray schedules applied on experimental plots at the Yakima, Wash., and Vincennes, Ind., laboratories of the United States Bureau of Entomology and Plant Quarantine were studied to determine the magnitude of parathion and DDT spray residues at harvest. The parathion sprays were prepared from 25% vet table powder and the DDT sprays from 50% wettable powder, except in one series of tests, when a 25% DDT wettable powder was used. All spray treatments were planned and made by members of the Division of Fruit Insect Investigations. Conventional hydraulic sprayers were used in this work. 

In 1948 spray schedules used experimentally in the Yakima Valley in the Pacific Northwest and in the Mississippi Valley were studied to determine the magnitude of the parathion spray residues during the interval between the last spray and harvest. DDT residues were also studied and results of analyses made at harvest are reported. 

Experimental. A second study was conducted with nine postmenopausal women age 51-65 yr. The subjects were fed standardized meals for 19 weeks. The mean composition for the 7-day menus of natural foods as % of total calories was 15% protein, 50% carbohydrate, 35% fat with a P/S ratio of 0.7, 10 g/day crude fiber, and less than 300 mg/day cholesterol. In addition, the diets supplied 1289 mg calcium, 1832 mg phosphorus, 2561 mg sodium and 5099 mg potassium daily. The diets met the RDA for all other nutrients. Calorie levels were adjusted to maintain body weight. The experimental meals were fed during the last six weeks of this 19-week period. No more than one liquid meal was consumed by each subject in one week. Fasting and postprandial samples of blood and urine were collected as in the previous study. Diuresis was induced by scheduled consumption of water. 

An experimental design approach was also used in Reference 26 for the chiral analysis of amino acid derivatives. The screening and optimization schedule followed... 

Fig. 1 Active choice of intravenous nicotine in experimentally naive squirrel monkeys, a Monkeys sat in chambers equipped with two levers and distinctly colored light stimuli above the levers. Completion of the response requirement (the ratio) on the active lever produced a brief 2-s presentation of a light stimulus and an intravenous injection of nicotine followed by a timeout (TO) period of 5-60 s. Completion of the ratio requirement on the inactive lever resulted in presentation of a brief 2-s light stimulus of a different color but no injection. The fixed-ratio (FR) response requirement was gradually increased over successive sessions from one to ten (FR 1-FR 10). b Mean percentage choice for responding on the active lever by monkeys when they were experimentally naive (first week under a FR 1 schedule) and when they had learned to self-administer nicotine under the FR 10, TO 60s schedule (first week under the FR 10 schedule). P < 0.01, compared to the first week of training. From Le FoU et al. (2007b)...

Goldberg SR, Henningfield JE (1988) Reinfordng effects of nicotine in humans and experimental animals responding under intermittent schedules of i.v. drug injection. Pharmacol Biochem Behav 30 227-234... 

In the course of our studies of iron-chloride systems, the stmcture determination of both monomeric and dimeric iron(III) chlorides are scheduled. Prior to the electron diffraction experiments, a mass spectrometric investigation of the vapor composition of iron(III) chloride was carried out as a function of the temperature under the electron diffraction experimental conditions ). It was establi ed that a nozzle temperature of 190 °C provides sufficient vapor pressure and the vapor consists of only dimeric molecules. In order to produce monomeric molecules whose relative abundance is an order of magnitude greater as regards the dimers, the chamber containing the nc e had to be heated to 450 °C while the other chamber, containing the sample was kept at about 200 °C. The analysis of the dimeric stmcture has been completed ) while that of the monomer is in progress. 

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