Azotobacter vinelandii strains lacking the nitrogenase-protective Shethna protein lost viability upon carbon-substrate deprivation in the presence of oxygen. This viability loss was dependent upon the N(2)-fixing status of cultures (N(2)-fixing cells lost viability, while non-N(2)-fixing cells did not) and on the ambient O(2) level. Supra-atmosheric O(2) tensions (40% partial pressure) decrease...

The topic of this paper are integer programming models in which a subset of 0/1-variables encode a partitioning of a set of objects into disjoint subsets. Such models can be surprisingly hard to solve by branch-and-cut algorithms if the order of the subsets of the partition is irrelevant. This kind of symmetry unnecessarily blows up the branchand-cut tree. We present a general tool, called orbi...

Trenchless technologies lie in the deposition, fixing or renovation of underground infrastructure with a little or even zero digging operations. Fixing operations are a special case of renovation, when the technical capacity of the pipelines is restored through sealing or local repairs. A sealing up operation lies in filling undug or leaking places with a sealing material or injecting liquid se...

Gauge fixing may be done in different ways. We show that using the chain structure to describe a constrained system, enables us to use either a perfect gauge, in which all gauged degrees of freedom are determined; or an imperfect gauge, in which some first class constraints remain as subsidiary conditions to be imposed on the solutions of the equations of motion. We also show that the number of...

Microorganisms decompose herbicides and they may serve as bioindicators of soil changes following herbicide application. Certain microbial species may be used as bioherbicides. This study has shown that Azotobacter is most sensitive to herbicide application; it is, therefore, a reliable indicator of the biological value of soil. The numbers of this group of nitrogen-fixing bacteria decrease con...

We parametrize the gauge-fixing freedom in choosing the Lagrangian of a topological gauge theory. We compute the gauge-fixing dependence of correlators of equivariant operators when the compactified moduli space has a non-empty boundary and verify that only a subset of these has a gauge independent meaning. We analyze in detail a simple example of such anomalous topological theories, 4D topolog...

Blue Green Algae (BGA) have the capacity to self generate photosynthates from CO and 2 water. It is gratifying to note that Aulosira is the most important alga of the rice fields of India. Algalization has been found to benefit all the growth parameters. The propagation of BGA enriches the N status of soil and also provides organic matter and biological quotient 2 substances for plant growth. T...