Further results on non-diagonal Bianchi type III vacuum metrics

We present the derivation, for these vacuum metrics, of the Painlev\'e VI equation first obtained by Christodoulakis and Terzis, from the field equations for both minkowskian and euclidean signatures. This allows a complete discussion and the precise connection with some old results due to Kinnersley. The hyperk\"ahler metrics are shown to belong to the Multi-Centre class and for the cases exhibiting an integrable geodesic flow the relevant Killing tensors are given. We conclude by the proof that for the Bianchi B family, excluding type III, there are no hyperk\"ahler metrics.Comment: 21 pages, no figure

Improved Vectors for Selecting Resistance to Hygromycin

Resistance to hygromycin B is an important dominant selectable marker in fungal transformation. Our goal was to improve vectors for hygromycin selection by making the gene more compact, by eliminating sites for commonly used restriction enzymes, and by subcloning the modified gene into convenient vectors. These improvements were made by modifying pCSN43 (Staben et al. 1989 Fungal Genetics Newsl. 36:79-81) through three rounds of megaprimer mutagenesis (Aiyar and Leis, 1993 Biotechniques 14:366-368 ), a technique based on polymerase chain reaction amplification. Plasmid pCSN43 has a 2.4 kb SalI fragment containing the bacterial hph gene (Gritz and Davies, 1983 Gene 25:179-188), encoding hygromycin B phosphotransferase, under control of the Aspergillus nidulans trpC promoter and terminator (Mullaney et al. 1985 MGG 199:37-45

A series of vectors for fungal transformation

We report a new fungal selectable marker that confers resistance to chlorimuron ethyl, a sulfonylurea herbicide. This gene as well as genes that confer resistance to hygromycin and bialaphos have been engineered to be compact and to eliminate sites for most common restriction enzymes. These three selectable markers have been used to construct a series of vectors for fungal transformation

Slowly Rotating Homogeneous Stars and the Heun Equation

The scheme developed by Hartle for describing slowly rotating bodies in 1967 was applied to the simple model of constant density by Chandrasekhar and Miller in 1974. The pivotal equation one has to solve turns out to be one of Heun's equations. After a brief discussion of this equation and the chances of finding a closed form solution, a quickly converging series solution of it is presented. A comparison with numerical solutions of the full Einstein equations allows one to truncate the series at an order appropriate to the slow rotation approximation. The truncated solution is then used to provide explicit expressions for the metric.Comment: 16 pages, uses document class iopart, v2: minor correction

Bianchi type II,III and V diagonal Einstein metrics re-visited

We present, for both minkowskian and euclidean signatures, short derivations of the diagonal Einstein metrics for Bianchi type II, III and V. For the first two cases we show the integrability of the geodesic flow while for the third case a somewhat unusual bifurcation phenomenon takes place: for minkowskian signature elliptic functions are essential in the metric while for euclidean signature only elementary functions appear

Gobierno y eficiencia de las cajas de ahorro espa¤olas

El presente trabajo analiza la relaci¢n existente entre la composici¢n y estructura de los ¢rganos de gobierno de las cajas de ahorros espa¤olas y su eficiencia en el a¤o 1999. Utilizando ecuaciones tobit los resultados del estudio constatan la existencia de una relaci¢n negativa entre la participaci¢n de las administraciones p£blicas en el consejo de administraci¢n de las cajas y su eficiencia en costes calculada, alternativamente, a trav‚s de un modelo de frontera eficiente y de la ratio gastos de explotaci¢n entre margen ordinario. Asimismo se evidencia una relaci¢n positiva entre la participaci¢n de pol¡ticos en el consejo y la canalizaci¢n de mayores recursos financieros hacia obras sociales.Teor¡a de la agencia; gobierno corporativo; consejo de administraci¢n; cajas de ahorros; eficiencia

Late-time phenomenology required to solve the H0H_0 tension in view of the cosmic ladders and the anisotropic and angular BAO data sets

The $\sim 5\sigma$ mismatch between the value of the Hubble parameter measured by SH0ES and the one inferred from the inverse distance ladder (IDL) constitutes the biggest tension afflicting the standard model of cosmology, which could be pointing to the need of physics beyond $\Lambda$CDM. In this paper we study the background history required to solve the $H_0$ tension if we consider standard prerecombination physics, paying special attention to the role played by the data on baryon acoustic oscillations (BAO) employed to build the IDL. We show that the anisotropic BAO data favor an ultra-late-time (phantom-like) enhancement of $H(z)$ at $z\lesssim 0.2$ to solve the tension, accompanied by a transition in the absolute magnitude of supernovae of Type Ia $M(z)$ in the same redshift range. The effective dark energy (DE) density must be smaller than in the standard model at higher redshifts. Instead, when angular BAO data (claimed to be less subject to model dependencies) is employed in the analysis, we find that the increase of $H(z)$ starts at much higher redshifts, typically in the range $z\sim 0.6-0.9$. In this case, $M(z)$ could experience also a transition (although much smoother) and the effective DE density becomes negative at $z\gtrsim 2$. Both scenarios require a violation of the weak energy condition (WEC), but leave an imprint on completely different redshift ranges and might also have a different impact on the perturbed observables. They allow for the effective crossing of the phantom divide. Finally, we employ two alternative methods to show that current data from cosmic chronometers do not exclude the violation of the WEC, but do not add any strong evidence in its favor neither. Our work puts the accent on the utmost importance of the choice of the BAO data set in the study of the possible solutions to the $H_0$ tension.Comment: 20 pages, 13 figures, 3 table

Identification of nonlinearity in conductivity equation via Dirichlet-to-Neumann map

We prove that the linear term and quadratic nonlinear term entering a nonlinear elliptic equation of divergence type can be uniquely identified by the Dirichlet to Neuman map. The unique identifiability is proved using the complex geometrical optics solutions and singular solutions

A miniprep procedure for isolating genomic DNA from Magnoporthe grisea

We have developed a simple miniprep procedure for the isolation of genomic DNA from the ascomycete Magnaporthe grisea. This pathogen of many grasses, including rice, has a moderate growth rate and produces intermediate to low numbers of conidia when grown in culture. Thus, in our previous DNA preparation procedure we inoculated swirling liquid cultures with mycelium that had been fragmented in a blender rather than with conidia. The mycelium obtained from these cultures was ground in liquid nitrogen for DNA extraction. Though the quantity and quality of DNA obtained by this method is satisfactory, the technique is too laborious for analysis of many strains. We developed the procedure described below to eliminate the need to fragment mycelium in a blender to inoculate cultures and to eliminate the need to grind mycelium in liquid nitrogen for DNA extraction. The new procedure, which relies on the enzymatic removal of cell walls and the lysis of protoplasts, should be readily adaptable to other filamentous fungi with growth characteristics similar to those of M. grisea