Tests of time-reversal invariance in atoms, molecules, and the neutron

Sensitive experiments have been developed that search for electric dipole moments of atoms, molecules, and the neutron. These experiments play an important role in deciding which of the myriad theoretical models correctly describes violations of the principle of time-reversal invariance.     

The national system of scientific measurement

Mandated measurement methods are required by regulatory agencies and other government groups. These methods exist for measuring almost all physical, chemical, and biological phenomena. The methods have been culled from the literature, from the organizations that write voluntary standards, and some have been developed by the agencies. Few provide adequate estimates of precision, and fewer still provide any evaluation of interlaboratory bias. The societal costs of these poor measurements are large. Much needs to be done to meet the physical and statistical requirements for establishing and maintaining dependable measurements. Excepting those directly supported by the National Bureau of Standards, most of the nation's measurement systems are uncontrolled.     

The influence of transient phenomena on the biodegradation of nitrilotriacetic acid in the activated sludge process I: Variations in hydraulic loading and sewage strength

The removal of nitrilotriacetic acid (NTA) following acclimatization in an activated sludge pilot plant has been studied during transient changes in operating conditions. These changes included increases in hydraulic loading and influent chemical oxygen demand (COD) and such phenomena in combination with transient temperature reductions. Short-term increases in hydraulic loading from 1 to 2 dry weather flow (dwf) had a very limited effect on NTA removal. Increasing the influent COD had a slight effect on NTA removal. Short term increases in hydraulic loading combined with transient reductions in temperature significantly reduced NTA removal. The effect of these combined changes on NTA removal was synergistic, rather than additive. Increases in influent COD combined with transient temperature reductions also caused a significant reduction of NTA removal. The effect of such combined changes on NTA removal was at most only additive.     

Prediction of herbage intake and liveweight gain of cattle grazing tropical pastures from the composition of the diet

As a basis for calculating growth rates of cattle within a model of a beef herd, three experiments were carried out. Their purpose was to (i) develop equations to predict organic matter, digestible organic matter and metabolisable energy intakes of cattle, (ii) establish the conversion of metabolisable energy to live weight of tropical cattle, and (iii) establish the validity of these relationships for predicting the liveweight change of grazing animals.In the first experiment, Brahman × Shorthorn crossbred cattle were held either indoors in pens or in long laneways outdoors where they walked approximately 5 km per day. Organic matter intake was measured in both situations and was found to be not significantly different between the situations. Regression equations were calculated relating intake of organic matter and digestible organic matter by cattle indoors to the chemical composition of their diet. The conversion of digestible organic matter to metabolisable energy intake and finally to liveweight gain was confirmed in a second experiment. The liveweight gain of outdoor animals was predicted accurately provided the metabolism of crossbred animals was considered and an allowance made for the energy required for walking.The diet selected by oesophageally fistulated animals at pasture was chemically analysed over a four-month period following these measurements. Feed intake and liveweight gain of non-fistulated animals grazing native and improved pastures were predicted from the chemical composition of the diet selected. There was good prediction of liveweight gain in both pasture situations.