Ultimate Constraint Research Articles

Virtue and truth in clinical science.

Since the time of Hippocrates, medical science sought to develop a practice based on "knowledge rather than opinion". However, in the light of recent alternative approaches to healing and a philosophy of science that, through thinkers like Kuhn, Rorty, and Foucault, is critical of claims to objective truth, we must reappraise the way in which medical interventions can be based on proven pathophysiological knowledge rather than opinion. Developing insights in Foucault, Lacan, and Wittgenstein, this essay argues for a recovery of the Aristotelian idea of a techne, where there is a dynamic interplay between praxis and conceptualization. The result is a post-Kuhnian epistemology for medical science that recognizes the evaluative dimension of knowledge, but that also looks to a Platonic conception of the good as the ultimate constraint on human thought, thus avoiding the radically self-contained accounts of truth found in some post-modern thinkers.

The sounds of bicolor damselfish (Pomacentrus partitus): Predictors of body size and a spectral basis for individual recognition and assessment

Evidence is provided that the ‘‘chirp,’’ a sound commonly produced by males of the bicolor damselfish (family: Pomacentridae) possesses an anatomical constraint: The peak frequency within its power spectrum reflects a clear inverse relationship to body size. For every 1-mm change in the standard length of a male (range: 50–69 mm), the peak frequency of its sounds shifts by approximately 20 Hz. The ultimate constraint appears to be the volume of an individual’s gas bladder. This provides an individualistic feature to the sounds of different sized colony members, all of whose sounds possess an otherwise extremely stereotyped temporal pattern of their included pulses. This finding may aid in clarifying the mechanism that provides the clue for the already established acoustical recognition of individuals within colonies of the species.

The State of the Public Finances

The State of the Public Finances

Impact of courtship feeding on clutch and third-egg size in glaucous-winged gulls

Gulls are usually not considered to be food-limited during the egg-laying stage. Egg-removal experiments have demonstrated the ability of gulls to lay additional eggs and to increase the size of the typically smaller third egg. Investigators in several recent studies, however, have invoked food limitation as a constraint on egg production. The relationship between courtship feeding rate, territory attendance, clutch size and third-egg size was studied in the glaucous-winged gull, Larus glaucescens. Courtship feeding rate rose steadily during the 30 days prior to laying, and peaked 2 days before the first egg was laid. Control males increased the amount of time they spent on their nesting territories and sharply decreased courtship feeding rate following the laying of the first egg. In contrast, males whose first and second eggs were removed experimentally within 12 h of laying, neither increased their territory attendance nor decreased their courtship feeding rate until after the third egg was laid. Females at experimental nests laid more eggs and heavier third eggs (relative to the weight of the first egg) than did females at control nests. Courtship feeding rate was negatively correlated with differences in weight between first and third eggs. The courtship feeding rate during egg laying appears to serve as a proximate constraint on third-egg size and may serve as either a proximate or an ultimate constraint on clutch size.

Seasonal Foraging Rates of Free-Ranging Moose

Foraging rates of free-ranging moose (Alces alces) in aspen (Populus spp.) boreal habitats were evaluated in summer, autumn, and winter. Consumption rates (g/min) increased asymptotically with biomass of potential forage, but both maximum rates and slopes varied seasonally. Maximum rates appeared related to forage quality since values declined from 23 g/minute in July to 11 g/minute in January. Slopes reflecting increments of foraging rate/unit increase in biomass seemed related to selectivity exercised by moose. The highest values were observed in winter when moose were least selective, the lowest in October when a mixture of green and cured forage offered the greatest opportunities for selective feeding. J. WILDL. MANAGE. 50(1): 143-147 Seasonal changes in the quality and availability of forage potentially limit daily food intake by moose throughout much of their biogeographical range. The ultimate constraint on dry matter intake for ruminants is rumen fill and hence rates of digestion and passage which are strongly influenced by physicochemical properties of forage. At another level, biomass and structure of vegetation influence feeding rates imposing an additional logistic constraint, particularly for large herbivores feeding in sparse habitats. Longer foraging times, higher biting rates, or greater bite sizes are tactics that herbivores can use to meet their daily forage requirements (Wickstrom et al. 1984). Total time devoted to feeding can be limited by search times and the need to ruminate while compensatory limits on bite rates and sizes are often dictated by vegetation characteristics. Following pioneering work on domestic animals (Allden and Whittaker 1970, Chacon and Stobbs 1976), several investigators have studied the intensity with which wild ungulates harvest food. The earliest of these considered feeding rates in relation to habitat type (Collins et al. 1978). This was followed by studies designed to determine how forage biomass and structure influenced feeding behavior of such species as caribou (Rangifer tarandus) (Trudell and White 1981), mule deer (Odocoileus hemionus) (Wickstrom et al. 1984), and elk (Cervus elaphus) (Nietfeld 1983, Wickstrom et al. 1984, Hudson and Nietfeld 1985). Comparable studies have not been conducted on large browsers such as moose. VivAs (in press) measured winter consumption rates of woody stems by moose in Norway, and Renecker and Hudson (1985) documented seasonal changes in dry matter intake by moose in central Alberta. But these measures have not been related to seasonal forage supplies. This study examined the logistics of foraging by moose in the aspen boreal environment and provided data on how seasonal changes in biomass of selected forages influenced feeding rates. Financial support was received from Alberta Rec., Parks and Wildl. Found., Agric. Res. Counc. Alberta, Alberta Envir. Trust, and Nat. Sci. and Eng. Res. Counc. We thank D. M. Renecker, D. M. Bayne, M. T. Nietfeld, C. D. Olsen, A. J. K ith, M. Young, and D. A. Welch for their skillful assistance in the field and R. G. Weingardt for help with statistical analysis.

A Quantitative Genetic Theory of Life History Evolution

Dynamic models of quantitative (polygenic) characters are more generally applicable in the analysis of life history evolution than are static optimization methods or one and two locus genetic models. A dynamic theory of life history evolution is derived by synthesizing population demography with quantitative genetics. In a population under weak selection with a nearly stable age distribution, the relative fitness of individuals with a particular life history phenotype can be approximated as an average of age—specific relative fecundity and mortality rates, weighted respectively by the present productivity and future reproductive value of each age—class. An adaptive topography is constructed showing that, with phenotype— and age—specific fecundity and mortality rates constant in time, evolution of the mean life history maximizes the intrinsic rate of increase of a population. However, the rate and direction of evolution in response to selection are strongly influenced by genetic correlations among characters. Negative genetic correlations among major components of fitness are often obscured phenotypically by positive environmental correlations, but commonly constitute the ultimate constraint on life history evolution, as illustrated by artificial selection experiments. Methods are suggested for measuring selective forces and evolutionary constraints that effect life history characters in natural populations.

Is the World Running Out of Raw Materials?*

T HE argument that the world is running out of raw materials has recently taken on a great deal of additional credibility. Oil prices have risen almost four-fold and many other commodities from wheat and sugar through to copper have also shown spectacular increases in price. In fact, the extent and ubiquity of the price increases in primary commodities has been unprecedented. One could almost say that never have so many commodities risen so far and so quickly in such a short time. There are several reasons for what has been happening, yet the proposition that the world is about to run out of raw materials is not one of them. As always in commodities, the reasons for the sharp movement in prices are due to factors on both the demand and supply sides. Had the price increases been due to resource depletion one would have expected the main factor on the supply side to have been the sheer limitation on increasing production beyond existing levels of capacity. But a closer look at the situation in most commodity markets will quickly reveal that production has not in fact been held back by an ultimate capacity constraint. On the contrary, the problems have been ones of disruption and dislocations in supply so that production has in many cases fallen well below potential capacity. This is true for agricultural commodities such as wheat, sugar and coffee where weather conditions have played havoc with the annual harvest or crop. Many metals have been hit by an unusual number of production disruptions due to strikes, political problems, as in Chile, or technical breakdowns at processing plants. This has been further aggravated by the introduction of stricter anti-pollution legislation as well as by one or two factors which have either forced the complete closure of processing plant pending the construction of new plant and equipment, or forced existing plant to operate at well below design capacities. Thus in zinc, for instance, around twenty per cent. of the non-socialist world smelting capacity has been closed down over the last three years. Even in the case of oil, where those who support the resource depletion argument can probably make out their strongest case, the price increases have also been associated with a substantial cutback in production.

Agricultural plot consolidation in the Auvergne region of Central France

Clout, H. D. 1974. Agricultural plot consolidation in the Auvergne region of Central France. Norsk geografisk Tidsskr. 28, 181–194. Plot consolidation has made great progress in the Paris Basin and has accentuated the agricultural contrast between northern innovation and southern backwardness. The Auvergne contains a wide range of agrarian structures, with environmental conditions being most favourable for farming in the lowland Limagnes. Detailed examination of Puy-de-Dôme département shows that most of the Limagnes have been consolidated, but little has been done in the uplands, which require other forms of structural change, including enlargement and re-afforestation. Plot consolidation is not a revolutionizing process since it cannot change land ownership, which is the ultimate constraint on its success.

Discussion: Firm Growth Research Opportunities and Techniques

Walker and Martin uncover a wealth of research opportunities in their widesweeping presentation. These opportunities arise on the basic premise that where growth is involved, the capital market is the ultimate constraint. Physical inputs are variable through buying and selling. A number of studies [5, bibliog.] have shown that the capital market presents a complex environment for farmers' decisions. Resource markets may be equally complex. It is under these conditions that Walker and Martin discuss opportunities and techniques for research. I propose to make additional comments on the contribution of static analyses to growth research, to expand on the three models which they present, and to suggest a potentially fruitful inductive technique which they have not covered.