University of Pavia

About: University of Pavia is a education organization based out in Pavia, Italy. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 21173 authors who have published 52524 publications receiving 1610492 citations. The organization is also known as: Università degli Studi di Pavia & Università di Pavia.

Continuous-spontaneous-reduction model involving gravity

Abstract: A continuous-reduction model implying the dynamical suppression of linear superpositions of macroscopically distinguishable states, presented recently by Di\`osi [Phys. Rev. A 40, 1165 (1989)], is investigated. The model exhibits appealing features; in particular, it relates reduction to gravity and contains no constants besides Newton's gravitational constant G. It turns out, however, that the model is not fully consistent. A slight modification of this model is proposed, which overcomes the difficulties and retains partially its appealing features. The resulting model deals with systems containing distinguishable or identical constituents, allows the derivation from microdynamics of wave-packet reduction, and accounts for the emergence of definite macroscopic properties for macro-objects. Reduction is related to gravity in the same way as in Di\`osi's model, but a fundamental length must be introduced to avoid inconsistencies.

The DNA binding site of HMG1 protein is composed of two similar segments (HMG boxes), both of which have counterparts in other eukaryotic regulatory proteins.

Abstract: The mammalian nuclear protein HMG1 contains two segments that show a high sequence similarity to each other. Each of the segments, produced separately from the rest of the protein in Escherichia coli, binds to DNA with high specificity: four-way junction DNA of various sequences is bound efficiently, but linear duplex DNA is not. Both isolated segments exists as dimers in solution, as shown by gel filtration and chemical crosslinking experiments. HMG1-like proteins are present in yeast and in protozoa: they consist of a single repetition of a motif extremely similar to the DNA binding segments of HMG1, suggesting that they too might form dimers with structural specificity in DNA binding. Sequences with recognizable similarity to either of the two DNA binding segments of HMG1, called HMG boxes, also occur in a few eukaryotic regulatory proteins. However, these proteins are reported to bind to specific sequences, suggesting that the HMG box of proteins distantly related to HMG1 might differ significantly from the HMG box of HMG1-like proteins.

Measurement of the linewidth enhancement factor of semiconductor lasers based on the optical feedback self-mixing effect

Abstract: A new method for the measurement of the linewidth enhancement factor of semiconductor lasers is presented, based on the interferometric self-mixing effect. It is a fast and easy to perform method that does not require radio frequency nor optical spectrum measurements. A small fraction of the emitted light is backreflected into the laser cavity by a remote target driven by a sine waveform. The mixing of the returned and the lasing fields generates a modulation of the optical output power in the form of an interferometric waveform, with a shape that depends on the optical feedback strength and the linewidth enhancement factor /spl alpha/, according to the well-known Lang-Kobayashi theory. We show that the value of /spl alpha/ can be retrieved from a simple measurement of two characteristic time intervals of the interferometric waveform. Experimental results obtained on different laser diodes show an accuracy of /spl plusmn/6.5%.

Prognostic factors for thrombosis, myelofibrosis, and leukemia in essential thrombocythemia: a study of 605 patients

Abstract: Background Essential thrombocythemia is a chronic myeloproliferative disorder; patients with this disorder have a propensity to develop thrombosis, myelofibrosis, and leukemia. Design and Methods We studied 605 patients with essential thrombocythemia (follow-up 4596 person-years) with the aim of defining prognostic factors for thrombosis, myelofibrosis, and leukemia during follow-up. Results Sixty-six patients (11%) developed thrombosis with a 10-year risk of 14%. Age >60 years ( p 60 years ( p =0.02) was significantly correlated with the development of leukemia. Cytotoxic treatment did not imply a higher risk of leukemia. At the time of the analysis, 64 of the 605 patients (10.6%) had died. The 10-year probability of survival was 88%, with a median survival of 22.3 years. Age >60 years ( p <0.001) and history of thrombosis ( p =0.001) were independent risk factors for survival. Conclusions The findings from this study on a large series of patients treated according to current clinical practice provide reassurance that essential thrombocythemia is an indolent disorder and affected patients have a long survival. The main risk is thrombosis, while myelofibrosis and leukemia are rare and late complications.