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dark energy with c ≥ 1 can be effectively described by a quintessence scalar-field. However, the variation of the quintessence scalar-field should be less than the Planck mass, which would give theoretic constraints on the parameters c and Ωm0. Therefore, we get the theoretical limits on the parameter

ABSTRACT Van der Pol's equation for a relaxation oscillator is generalized by the addition of terms to produce a pair of non-linear differential equations with either a stable singular point or a limit cycle. The resulting "BVP model " has two variables of state, representing

an upper-envelope NPP unconstrained by resource limitations. This theoretical maximum NPP approached 200 tC ha−1 yr−1 at point locations, roughly 2 orders of magnitude higher than most current managed or natural ecosystems. Recalculating the upper envelope estimate of NPP limited by available water reduced

University’s Lady Mar-garet Hall on the occasion of the Econometric Society World Congress in Cambridge. After the speech there were questions. First the late Professor Joan Robinson asked whether monetarism had any theoretical foundation. Professor Friedman answered that monetarism was an empirical matter

Antibiotic resistance can result either from mutations within a chromosomal gene or from mobile genes imported from outside. In the last 15 years, some of these mobile genes have shown a propensity to adapt to successive antibiotic challenges, the most versatile being the class A b-lactamases. The TEM and SHV b-lactamase nuclei, usually after one initial critical mutation, allow a series of successive mutations that increase the spectrum to hydrolyze most cephalosporins. The class C b-lactamases also show some versatility; while it migrates from the chromosome, subtle changes can occur in the gene to broaden the spectrum. Trimethoprim resistance has shown less adaptability in gram-negative bacteria, but in gram-positive organisms the plasmid has captured the chromosomal dihydrofolate reductase of Staphylococcus epidermidis, and a minimal number of changes have occurred that decrease the binding of trimethroprim. Other resistance mechanisms appear less adaptable, relying rather on the importation of new genes to cope with new challenges. The introduction of molecular biological techniques to the replication because there is no replication of the transposon during the transposition process [6, 7]. On the other hand,study of antibiotic resistance genes has enabled us to follow the spread and evolution of these genes through the clinical class II transposons contain a transposase, which sets up a co-integrate intermediate between the transposon-containing repli-population. What is the most significant factor in the diversifi-

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Abstract not found

An attempt is made to apply information-theoretic computational complexity to metamathematics. The paper studies the number of bits of instructions that must be a given to a computer for it to perform finite and infinite tasks, and also the amount of time that it takes the computer to perform

analytically derive the average size of the contention window that maximizes the throughput, hereafter theoretical throughput limit, and we show that: 1) depending on the network configuration, the standard can operate very far from the theoretical throughput limit; and 2) an appropriate tuning of the backoff