Lorentz Transformation from Symmetry of Reference Principle

The Lorentz Transformation is traditionally derived requiring the Principle of Relativity and light-speed universality. While the latter can be relaxed, the Principle of Relativity is seen as core to the transformation. The present letter relaxes both statements to the weaker, Symmetry of Reference Principle. Thus the resulting Lorentz transformation and its consequences (time dilatation, length contraction) are, in turn, effects of how we manage space and time.Comment: 2 page

Plasma and PBMC miRNA profile in sexually HIV-1 exposed seronegative individuals

Background: MicroRNAs (miRNAs) are small 20- to 24-nt non-coding RNAs involved in the post-transcriptional regulation of gene expression which play important defensive roles in several viral infections. Global expression profiles of cellular miRNAs have identified alterations of specific miRNAs post-HIV-1 infection both in vitro and in different patient cohorts suggesting potential roles for miRNA in pathogenesis and disease progression. We therefore decided to verify if natural resistance to HIV-1 infection observed in seronegative individuals repeatedly exposed to HIV-1 (HESN) through unprotected sexual intercourse could be secondary to a different expression of their miRNA profile. Methods: Expression levels of 25 miRNAs selected according to their proven anti-HIV-1 properties were analyzed in plasma, basal PBMC and in in vitro HIV-1 infected macrophages isolated from 30 HESN, 30 HIV seropositive subjects (HIV + ) and 30 healthy controls (HC).Results: In plasma the expression of mir-155, mir-382, mir-28 and mir-198 was significantly augmented in both HIV + and HESN compared to HC probably as a consequence of viral exposure. Conversely the expression of mir-223 and mir-150 in plasma was significantly increased only in HESN and this result was also confirmed in basal PBMC suggesting a protective effect for these miRNAs in resistance to HIV-1 infection. Furthermore, the expression of mir-150 was significantly increased in HESN macrophages following HIV-1 infection. Conclusions: mir-223 and mir-150 can target the 3\ua2UTR of HIV-1 transcripts, and they have already been identified as anti-HIV-1 miRNAs. The higher expression of these miRNA in HESN samples could therefore represent a key protection mechanism against HIV infection

Relativity principles in 1+1 dimensions and differential aging reversal

We study the behavior of clocks in 1+1 spacetime assuming the relativity principle, the principle of constancy of the speed of light and the clock hypothesis. These requirements are satisfied by a class of Finslerian theories parametrized by a real coefficient $\beta$, special relativity being recovered for $\beta=0$. The effect of differential aging is studied for the different values of $\beta$. Below the critical values $|\beta| =1/c$ the differential aging has the usual direction - after a round trip the accelerated observer returns younger than the twin at rest in the inertial frame - while above the critical values the differential aging changes sign. The non-relativistic case is treated by introducing a formal analogy with thermodynamics.Comment: 12 pages, no figures. Previous title "Parity violating terms in clocks' behavior and differential aging reversal". v2: shortened introduction, some sections removed, pointed out the relation with Finsler metrics. Submitted to Found. Phys. Let