Taylor's Law holds in experimental bacterial populations but competition does not influence the slope

Populations vary in time and in space, and temporal variation may differ from spatial variation. Yet, in the past half century, field data have confirmed both the temporal and spatial forms of Taylor's power Law, a linear relationship between log(variance) and log(mean) of population size. Recent theory predicted that competitive species interactions should reduce the slope of the temporal version of Taylor's Law. We tested whether this prediction applied to the spatial version of Taylor's Law using simple, well-controlled laboratory populations of two species of bacteria that were cultured either separately or together for 24 h in media of widely varying nutrient richness. Experimentally, the spatial form of Taylor's Law with a slope of 2 held for these simple bacterial communities, but competitive interactions between the two species did not reduce the spatial Taylor's Law slope. These results contribute to the widespread usefulness of Taylor's Law in population ecology, epidemiology and pest control.     

The role of “forensic” dendrochronology in the conservation of alerce (Fitzroya cupressoides ((Molina) Johnston)) forests in Chile

Dendrochronological techniques have proved to be an effective tool in the investigation of illegal cutting of Fitzroya because it is illegal to trade and cut wood coming from living individuals or from trees that were killed after 1976 either by natural or anthropogenic causes. Accurate cross-dating of death or burn dates provides strong evidence for prosecution in the legal enforcement of the ban and an important defense in the protection of this and other endangered species. Some examples illustrate the application of these dating techniques and discuss potential difficulties.     

National fisheries chart 2000: a new instrument for fisheries management in inland waters

Institutional and legal frameworks have a widescope and need for improving or refiningexisting fisheries management tools, and forincreasing capabilities of the public andprivate sectors to better manage thedevelopment of fisheries activities, either inmarine or freshwater ecosystems. Despite thelarge surface area covered by inland waters inMexico, its production during the last 20 yearsremained at the same level, i.e. productionused for local consumption in rural areassupports food for the poorest communities. Thepresent document deals with the most recentlegal exercise that shows that there are manyopportunities to strengthen technicalcooperation and develop policies and commercialissues related to freshwater fish in inlandwaters.The Mexican federal administration during theyears 1994 to 2000 fully endorsed policies thatbenefited the relationship between thegovernment and fisheries sector. The Code ofConduct for Responsible Fisheries (CCRF), wasadopted in 1995 as a global intergovernmentalconsensus on the promotion of sustainablefisheries and aquaculture developments.Following its basic principles and norms, theNational Fisheries Institute (INP) elaboratedthe National Fisheries Chart in 2000. This isan example of recent advances to develop legalinstruments that fit the need for fisheriesmanagement. Such efforts and theirimplementation can be seen through technicaldata sheets in the (CNP) as well as othersuggestions provided to further promote thesustainable development of inland fisheries inMexico.     

Ideologies of discrimination: personhood and the ‘genetic group’

‘Ideologies of Discrimination’ considers the implications of the new genetics for understandings of personhood and for understandings of the relationship between people in groups. In particular, the essay delineates and examines the emerging notion of a ‘genetic group’ and considers the social implications of redefining families, racial groups and ethnic groups through express, and often exclusive, reference to a shared genome. One consequence of such redefinition has been the justification and elaboration of stigmatizing images of and discrimination against such groups—especially those, such as Jews and African-Americans, that have long been identified with specific somatic characteristics. A few worrisome trends begin to emerge in the response of the American legal system to the notion of genetic groups. Among these is a shift in the locus of privacy and identity from the autonomous individual to the genetic group. This shift challenges (and threatens) long-standing Western values (including equality and liberty) that depend upon the ideological centrality of autonomous individuality.     

Between Knowledge And Technology: Patenting Methods,Rethinking Materiality

How does the law construe certain things and activities as knowledge that can become the object of intellectual property? When we look at the quantitative trends in recent patenting activities—more people patenting many more things—we tend to view that, in part, as an effect of the law's ability to construe new kinds of innovation (software, genetic sequences, etc.) in ways that conform to established legal concepts of patentable invention. The assumption is that what changes is not the shape of the box called invention, but the objects that are made to fit that box. But in fact while new technologies produce new innovations, the very concept of invention has not just expanded but undergone substantial qualitative change. The wave of inventive activity associated with the industrial revolution led to an unprecedented reliance on patenting, but as the law articulated ways to protect those inventions, it also took their emblematic form—the machine—as the template for the legal concept of invention. Analogously, the recent reinterpretations of patent law to enable the protection of living organism and biological entities have challenged and modified the traditional machine-inspired concept of invention, initiating a trend toward a more developmental one. The information-based inventions discussed here may elicit a reconceptualization of invention in yet another way.     

Are there ethnic groups in South Asia?

The question whether there are ethnic groups in South Asia is relevant to the application of international law, as when states report under the International Convention on the Elimination of All Forms of Racial Discrimination. Whether it is important to the advancement of social science is less certain. To classify certain groups as ethnic groups adds little to the explanation of the character of inter-group relations in the region.     

Theoretical considerations on the C-D effect in self-thinning plant populations

A model for describing the competition–density (C-D) effect in self-thinning populations was developed on the basis of the following three basic assumptions: (1) the growth of mean phytomass follows a general logistic equation; (2) final yield is independent of initial population density; and (3) there exists a functional relationship between actual and initial population densities at any given time. The resultant equation takes the same reciprocal form as the reciprocal equation of the C-D effect derived from Shinozaki–Kira's theory (i.e., the logistic theory of the C-D effect), which deals with the density effect in nonself-thinning populations. However, one of the two time-dependent coefficients is quite different in mathematical interpretation between the two reciprocal equations. The reciprocal equation for self-thinning populations is essentially the same as the reciprocal equation assumed in the derivation of the functional relationship between actual and initial population densities. The establishment of the reciprocal equation is supported by the empirical facts that the reciprocal relationship between mean phytomass and population density is discernible in not only nonself-thinning populations but also in self-thinning populations. The present model is expected to systematically interpret underlying mechanisms between the C-D effect, which is observed at a time constant among populations with various initial densities, and self-thinning, which is observed along a time continuum in a given population. Received: August 5, 1998 / Accepted: January 7, 1999     

Can the United States Establish the Outer Limits of Its Extended Continental Shelf Under International Law?

Although most provisions of the United Nations Convention on the Law of the Sea are regarded customary international law and the United States views most of its provisions as such, the outsider status of the United States causes problems in some areas, especially concerning the continental shelf beyond 200 nautical miles. This article asks whether it is possible for the United States to establish the outer limits of its continental shelf beyond 200 nautical miles in line with international law without becoming a state party to the convention, and if that is possible, how could the United States proceed?     

Uptake Kinetics,Species Differences,and the Determination of Equivalent Combinations of Air Concentration and Exposure Duration for Assessment of Acute Inhalation Toxicity

For acute inhalation toxicity assessment, I develop a conceptual framework for expressing combinations of intensity (air concentration) and duration that produce equivalent toxicity by examining how the shape of the body-burden uptake curve during a bout of inhalation interacts with various pharmacodynamic measures of the critical body burden needed to produce toxicity. If toxicity depends on attaining a critical tissue concentration, three existing empirical approaches—Haber's Law, the ten Berge equation, and pure air-concentration-dependence—are but local approximations to different parts of an overarching mathematical relationship. The compound-specific half-life of elimination determines the range of durations for which each applies: durations of one half-life or shorter follow Haber's Law, exposures of 4 or more half-lives follow pure air-concentration-dependence, and intermediate durations can be approximated by the ten Berge equation. Better animal-to-human extrapolation is achieved if exposure durations are expressed as number of species-specific half-lives. I consider several alternative pharmacodynamic criteria, such as the dependence of toxicity on time spent above a critical tissue concentration, or on the area under the tissue concentration curve, on the tissue concentration of a toxic metabolite, or on the imbalance of damage and repair processes.     

Stochasticity in reproductive opportunity and the evolution of egg limitation in insects

Is reproduction by adult female insects limited by the finite time available to locate hosts (time limitation) or by the finite supply of eggs (egg limitation)? An influential model predicted that stochasticity in reproductive opportunity favors elevated fecundity, rendering egg limitation sufficiently rare that its importance would be greatly diminished. Here, I use models to explore how stochasticity shapes fecundity, the likelihood of egg limitation, and the ecological importance of egg limitation. The models make three predictions. First, whereas spatially stochastic environments favor increased fecundity, temporally stochastic environments favor increases, decreases, or intermediate maxima in fecundity, depending on egg costs. Second, even when spatially or temporally stochastic environments favor life histories with less‐frequent egg limitation, stochasticity still increases the proportion of all eggs laid in the population that is laid by females destined to become egg limited. This counterintuitive result is explained by noting that stochasticity concentrates reproduction in the hands of a few females that are likely to become egg limited. Third, spatially or temporally stochastic environments amplify the constraints imposed by time and eggs on total reproduction by the population. I conclude that both egg and time constraints are fundamental in shaping insect reproductive behavior and population dynamics in stochastic environments.