The \u3ci\u3eAspergillus nidulans snt\u3c/i\u3e Genes Are Required for the Regulation of Septum Formation and Cell Cycle Checkpoints

In Aspergillus nidulans, germinating conidia undergo multiple rounds of nuclear division before forming a septum. Previous genetic results suggest that the ability to separate nuclear division and septum formation depends upon a threshold level of activity of the cyclin-dependent kinase NIMXcdk1. Mutations in nimX and nimT, the gene encoding the NIMXcdk1-activating phosphatase, have revealed that Tyr-15 phosphorylation is important for determining the timing of the formation of the first septum. Here, we describe a screen for suppressors of nimT23 (snt), designed to identify additional components of the pathway regulating septum formation. We show that a subset of the snt mutants are defective in the temporal regulation of septum formation and in cell cycle checkpoint responses. Molecular characterization of sntA shows that it is allelic to the previously described ankA gene, which encodes the NIMXcdk1 Tyr-15 kinase. Additional experiments described in this study show that nutritional conditions modulate the timing of septum formation and alter the phenotypes displayed by the snt mutants. A model that suggests that the timing of septum formation is influenced by DNA damage and glucose availability via the sntA and sntB gene products is proposed

In Defense of the Incorporation Strategy

Contract law must provide rules for interpreting the meaning of express terms and default rules for filling contractual gaps. Article 2 of the Uniform Commercial Code provides the same response to both demands: It incorporates the norms of commercial practice. This incorporation strategy has recently come under attack. Although the incorporation strategy for gap-filling seems to have survived criticism, the incorporation strategy for interpretation remains heavily criticized. Critics charge that the expected rate of interpretive error under an incorporationist interpretive regime is so excessive that almost any plain meaning regime would be preferable. The attack on the incorporation strategy for interpretation is fundamentally flawed. The best interpretive regime is one that, all else equal, minimizes the sum of interpretive error costs and the costs of specifying contract terms. Critics of the incorporation strategy have focused exclusively on the former and completely ignored the latter. Yet the chief virtue of the incorporation strategy for interpretation is its promise to yield specification costs well below that of plain meaning regimes. Even if plain meaning regimes have lower interpretive error costs, the incorporation strategy is superior if its lower specification costs outweigh its higher interpretive error costs. Moreover, most critics treat their objections to Article 2 as objections to the incorporation strategy generally. But Article 2 is just one possible institutional variant of the incorporation strategy. All of the sources of interpretive error critics identify can be substantially reduced, if not avoided, by making feasible alterations to Article 2 that nonetheless preserve its incorporationist character. This Article defends the incorporation strategy as a method of contractual interpretation. Part II analyzes the debate between incorporation and plain meaning regimes. After explaining the comparative and empirical nature of this debate, we present the intuitive case for believing that incorporationist interpretive regimes will yield significantly lower specification costs than plain meaning regimes. Part III considers recent objections to the incorporation strategy for interpretation. These objections identify several potential sources of interpretive error and offer both a priori and empirical arguments to suggest these errors are likely to be extensive in any incorporation regime. We argue that these criticisms overstate the probable extent of interpretive error under Article 2, and that all of the kinds of interpretive errors identified can be significantly reduced by feasible changes to Article 2. Part IV describes the salient features in Article 2 that implement the incorporation strategy and presents possible amendments to reduce the extent of the interpretive errors identified in Part III. Given the distinction between the incorporation strategy and its implementation, Article 2 can accommodate these amendments without abandoning the incorporation strategy. Part V concludes by summarizing the argument for favoring the incorporation strategy for interpreting contracts among a heterogeneous group of contractors: Compared to a plain meaning regime, the lower contract specification costs of a carefully designed incorporation regime will outweigh its higher interpretive errors costs

Synthesis and Testing of Compounds That Inhibit Soybean Cyst Nematode Egg Hatch

Soybean cyst nematode infestation continues to be a serious agricultural problem. As part of an interdisciplinary effort to identify a biorational solution to the problem, analogs of glycinoeclepin A, a natural hatching stimulus of the nematode, were prepared and tested. Several of the analogs were discovered to inhibit the hatching of soybean cyst nematode eggs. On the basis of the results of egg hatch tests, the minimum functionality for egg hatch inhibition appears to be a keto diacid

Testing for Majorana Zero Modes in a Px+iPy Superconductor at High Temperature by Tunneling Spectroscopy

Directly observing a zero energy Majorana state in the vortex core of a chiral superconductor by tunneling spectroscopy requires energy resolution better than the spacing between core states $\Delta^2/eF$. We show that nevertheless, its existence can be decisively tested by comparing the temperature broadened tunneling conductance of a vortex with that of an antivortex even at temperatures $T >> \Delta^2/eF$.Comment: 5 pages, 4 figure

Majorana fermions of a two-dimensional Px+iPy superconductor

To investigate Majorana fermionic excitations of a $p_x+ip_y$ superconductor, the Bogoliubov-de-Gennes equation is solved on a sphere for two cases: (i) a vortex-antivortex pair at opposite poles and (ii) an edge near the south pole and an antivortex at the north pole. The vortex cores support a state of two Majorana fermions, the energy of which decreases exponentially with the radius of the sphere, independently of a moderate disorder potential. The tunneling conductance of an electron into the superconductor near the position of a vortex is computed for finite temperature, and is compared to the case of an {\it s}-wave superconductor. The zero bias conductance peak of the antivortex is half that of the vortex. This effect can be used as a probe of the order parameter symmetry, and as a direct measurement of the Majorana fermion.Comment: 15 pages, 17 figure