Resolution of singularities of surfaces by P. Del Pezzo. A mathematical controversy with C. Segre

We examine in some detail a series of papers published by P. Del Pezzo and C. Segre on the resolution of singularities of algebraic surfaces, trying to point out the main ideas.In 1888 P. Del Pezzo published a proof of the resolution of singularities of algebraic surfaces using birational transformations. He introduced the notion of equisingularity of two surfaces at a point or along a curve. This notion is made specific in a paper of 1889. C. Segre in his famous paper on infinitely near multiple points on a surface published in 1896 shows that Del Pezzo's method does not always produce a smooth surface. During 1897 each author reasserts his point of view in several papers which contain interesting remarks, regardless of their increasingly polemic style.     

The 'solar model problem' solved by the abundance of neon in nearby stars

The interior structure of the Sun can be studied with great accuracy using observations of its oscillations, similar to seismology of the Earth. Precise agreement between helioseismological measurements and predictions of theoretical solar models has been a triumph of modern astrophysics. A recent downward revision by 25-35 per cent of the solar abundances of light elements such as C, N, O and Ne (ref. 2) has, however, broken this accordance: models adopting the new abundances incorrectly predict the depth of the convection zone, the depth profiles of sound speed and density, and the helium abundance. The discrepancies are far beyond the uncertainties in either the data or the model predictions. Here we report neon-to-oxygen ratios measured in a sample of nearby solar-like stars, using their X-ray spectra. The abundance ratios are all very similar and substantially larger than the recently revised solar value. The neon abundance in the Sun is quite poorly determined. If the Ne/O abundance in these stars is adopted for the Sun, the models are brought back into agreement with helioseismology measurements.     

A functional variant of lymphoid tyrosine phosphatase is associated with type I diabetes

We report that a single-nucleotide polymorphism (SNP) in the gene (PTPN22) encoding the lymphoid protein tyrosine phosphatase (LYP), a suppressor of T-cell activation, is associated with type 1 diabetes mellitus (T1D). The variants encoded by the two alleles, 1858C and 1858T, differ in a crucial amino acid residue involved in association of LYP with the negative regulatory kinase Csk. Unlike the variant encoded by the more common allele 1858C, the variant associated with T1D does not bind Csk.     

Singolarità e geometria sopra una superficie nella corrispondenza di C. Segre a G. Castelnuovo

Memoria presentata da U. Bottazzini     

Electrolyte content of the cerebral cortex in developing rats after prenatal X-radiation

Zusammenfassung Bei in utero röntgenbestrahlten Rattenembryonen wurden die Elektrolyte im Gehirncortex bestimmt. Während der K-Gehalt unverändert blieb, war derjenige von Na und Cl bei 9 Tage alten Tieren erniedrigt. Zytologische Veränderungen, durch pränatale Bestrahlung verursacht, waren mit diesen Befunden korreliert.

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This work was supported by contract AT(11-1)-34, Project 82, from the U.S. Atomic Energy Commission.     

Cocci and diphtheroids in blood cultures from patients in various pathological situations

Summary The evolution of cocci and diphtheroids taking origin from cell-wall-deficient forms seems not to be related to a particular state of illness, but to be the consequence of a generalized crypto-infection.