Rapid evolution of a native species following invasion by a congener.

In recent years, biologists have increasingly recognized that evolutionary change can occur rapidly when natural selection is strong; thus, real-time studies of evolution can be used to test classic evolutionary hypotheses directly. One such hypothesis is that negative interactions between closely related species can drive phenotypic divergence. Such divergence is thought to be ubiquitous, though well-documented cases are surprisingly rare. On small islands in Florida, we found that the lizard Anolis carolinensis moved to higher perches following invasion by Anolis sagrei and, in response, adaptively evolved larger toepads after only 20 generations. These results illustrate that interspecific interactions between closely related species can drive evolutionary change on observable time scales.

Knowledge-based function optimization using fuzzy cultural algorithms with evolutionary programming.

In this paper, the advantages of a fuzzy representation in problem solving and search is investigated using the framework of Cultural algorithms (CAs). Since all natural languages contain a fuzzy component, the natural question is "Does this fuzzy representation facilitate the problem-solving process, within these systems". In order to investigate this question we use the CA framework of Reynolds (1996), CAs are a computational model of cultural evolution derived from and used to express basic anthropological models of culture and its development. A mathematical model of a full fuzzy CA is developed there. In it, the problem solving knowledge is represented using a fuzzy framework. Several theoretical results concerning its properties are presented. The model is then applied to the solution of a set of 12 difficult, benchmark problems in nonlinear real-valued function optimization. The performance of the full fuzzy model is compared with 8 other fuzzy and crisp architectures. The results suggest that a fuzzy approach can produce a statistically significant improvement in search efficiency over nonfuzzy versions for the entire set of functions, the then investigate the class of performance functions for which the full fuzzy system exhibits the greatest improvements over nonfuzzy systems. In general, these are functions which require some preliminary investigation in order to embark on an effective search.

A hierarchical model of the evolution of cooperation in cultural systems.

In this paper the following problem is addressed: "Under what conditions can a collection of individual organisms learn to cooperate when cooperation appears to outwardly degrade individual performance at the outset. In order to attempt a theoretical solution to this problem, data from a real world problem in anthropology is used. A distributed simulation model of this system was developed to assess its long term behavior using using an approach suggested by Zeigler (Zeigler, B.P., 1984, Multifaceted Modelling and Discrete Event Simulation (Academic Press, London)). The results of the simulation are used to show that although cooperation degrades the performance potential of each individual, it enhances the persistence of the individual's partial solution to the problem in certain situations."

Lead-erythrocyte protoporphyrin correlation in blood of exposed workers.

A systematic survey of blood samples from 174 industrial workers occupationally exposed to lead fumes and lead dust, revealed some poor correlations between the lead (Pb) level and the free erythrocyte protoporphyrin (FEP) level. In addition to those workers who had an expected correlation (normal Pb-normal FEP or elevated Pb-elevated FEP) there were two groups with atypical correlations. In one group a normal Pb level was associated with an elevated FEP level and in the other group an elevated Pb level was associated with a normal FEP level. This shows that neither the Pb nor the FEP test can substitute for the other. Since the individual FEP response to Pb absorption is unpredictable, both tests should be carried out routinely. This would make it possible to determine simultaneously the degree of absorption (Pb level) and the degree of intoxication (FEP level) and would improve significantly the assessment of undue lead absorption of occupationally exposed workers. If, however, only one of these tests is used for screening the other test should always be carried out as a confirmatory test when the screening detects an elevated Pb or FEP level.

Quantitative analysis of human serum cholesterol by thin-layer chromatographic spot test.

A fast, inexpensive, simple method is described for the determination of the total cholesterol concentration in human serum. The cholesterols (free and esterified) are extracted from serum by a double extraction procedure, using isopropanol-water-10 N sodium hydroxide (250:125:10) and then n-octane. An aliquot of the octane extract is spotted on a thin-layer plate and the cholesterol in the spot is rendered visible using an aqueous phosphomolybdic acid staining solution and a heat treatment for the color development. The colored spot is scanned with a densitometer.

N-nitrosomorpholine and N-nitrosobutylamine-stimulated DNA synthesis in BHK-21/C13 cells.

Non-semiconservative DNA synthesis was examined in BHK-21/C13 cells after treatment with the aliphatic N-nitrosobutylamine (NB) and the heterocyclic N-nitrosomorpholine (NM). The extent of repair synthesis after alkylation was compared quentitatively and calculations were made of the amount of DNA damage per cell and number of bases inserted per damaged site. Of the chromosome aberrations caused by NM the most predominant were dicentrics. Other aberrations included fragments, gaps, breaks and exchanges of both the chromatid and chromosome type. Unlike NM, NB elicted a higher frequency of chromatid breaks.