An integral equation approach to measuring turnover in nonsteady compartmental and distributed systems

Physiological systems are often modelled by a set of compartments. Alternatively they can be described by the diffusion-convection-reaction equations governing distributed systems. The problem considered here is that of identifying a continuously changing input of some metabolite )tracee), endogenous to the system and hence inaccessible, when a nonlinear or time-varying component is also introduced into the loss parameter, as for example through feedback mechanisms. A tracer is used to determine the steady-state impulse response under time-invariant, linear conditions. A known input of tracer is also administered when the system is driven out of steady state. The integral equations developed utilize the predetermined impulse response, the measured concentrations of both tracer and tracee (output) in some region of the system to estimate the changing loss parameter and the unknown input in a continuous fashion.     

Epidemiological approach to surgical management of the casualties of war.

The nature of modern conflicts precludes adequate medical care for most people wounded in wars. The traditional military approach of echeloned care for those wounded on the battlefield has limited relevance. I present an alternative, epidemiological approach whereby some effective care may reach many more. For a surgical facility to have a positive impact by using surgical and anaesthetic competence there must be access to the wounded; security for staff and patients; and a functioning hospital infrastructure. These all depend on respect for the first Geneva convention. Early hospital admission for urgent surgery is not so important if there is adequate first aid beforehand. The hospitals of the International Committee of the Red Cross have provided surgical care for thousands of wounded people by fulfilling these conditions. People wounded in modern conflicts would fare better if these priorities were recognised and less emphasis was placed on the more spectacular aspects of surgical care that benefit only a few.     

An airtight approach to the inebriometer

The mechanism by which inhaled anesthetics work is not fully understood, although they have been extensively used. Much research has been done showing the likelihood that there is more than one pathway or mechanism of action. A long-term goal of our laboratory is to decipher these mechanisms using Drosophila melanogaster, an excellent model organism for this purpose. In order to do this, we have modified and constructed an apparatus called the inebriometer to quantitatively analyze the response of flies to inhaled anesthetics. While the inebriometer is not new to the fly community, our updated design provides a relatively low-labor, high-throughput means for performing screens in search of genes involved in the anesthetic mechanism. Here we describe our construction of an airtight inebriometer that we have designed for this purpose. We also provide data that validates this apparatus and establishes a procedure for its use.     

An approach to the chemosystematics of the zygophyllaceae

The Zygophyllaceae occur in arid zones and have been reported to contain, among other compounds, flavonoids and alkaloids. The flavonoids in representatives of three of the seven subfamilies have been studied and their distribution is discussed with respect to their chemosystematic significance. The aglycones identified were kaempferol, quercetin, isorhamnetin, herbacetin and herbacetin-8-O-methyl ether. Glycosidic patterns elucidated range from mono- to tri-glycosides, five of which are novel in plants. Alkaloids were also shown to be present, and the importance of those cited in the literature has been surveyed in relation to the chemosystematics of the Zygophyllaceae.     

An approach to chemotaxonomy of the Asarum subgenus

A survey of chemical composition of 23 species of Asarum subgenus Heterotropa showed that the five groups could be distinguished on the basis of the presence or absence of asatone, phenol ethers and terpenes.     

An approach to the biometeorology of decomposer organisms

A search for surrogate variables of weather's control over rate of decay by decomposer organisms has revealed that Actual Evapotranspiration (AE), a water budget term, correlates well (r = 0.976) with measured values of litter decomposition rate. Using data from many biomes of the earth, a curve-fit of AE with measured decomposition rate has been formulated. This curve-fit has been used to prepare a map which displays the geography of predicted decay rate for North America. The physical properties of the litter also controls decomposition rates. Work is in progress to refine the AE to decomposer relationship by considering the lignin content of decomposing litter. Preliminary results suggest that control of decomposition rates by lignin increases with AE so that in high AE environments small changes in lignin concentration result in large changes in litter decay rates. This relationship perhaps explains the great variability in decay rates reported in tropical ecosystems.     

An anthropometric approach to the study of evolution

The study of human evolution has always been a major issue in physical anthropology. Since computers became available this study became a new dimension in that it became feasible to apply advanced mathematical multivariate methods which make use of morphometric data. However, looking back on what has been achieved so far with these methods, it must be admitted that the results obtained are often unsatisfactory. This has led to a certain lack of acceptance of these methods. In the present paper it is argued that very useful results may be obtained by applying more sophisticated multivariate methods which are specifically designed for the anthropological problems at issue. Three examples are given. The first deals with the controversy between "Creationism" on the one hand and "Evolutionism" on the other. Our results strongly support the Evolutionists' point of view. The second example deals with the reconstruction of human phylogeny. An investigation is discussed which has led to a startling new hypothesis concerning the evolution of man. The last example concerns a preliminary investigation of trends in human sexual dimorphism. The results obtained so far seem to support the opinion expressed by other workers that tendencies exist in our modern society which lead to changes in the present dimorphism.