Nonacceptability criteria and closure properties for the class of languages accepted by binary systolic tree automata

AbstractIn this paper a contribution is given to the solution of the problem of finding an inductive characterization of the class of languages accepted by binary systolic tree automata, L(BSTA), in terms of the closure of a class of languages with respect to certain operations. It is shown that L(BSTA) is closed with respect to some new operations: selective concatenation, restricted concatenation and restricted iteration. The known nonclosure of L(BSTA) with respect to classical language operations, like concatenation and Kleene iteration is proved here by using a new nonacceptability criterion

The interaction between transpolar arcs and cusp spots

Transpolar arcs and cusp spots are both auroral phenomena which occur when the interplanetary magnetic field is northward. Transpolar arcs are associated with magnetic reconnection in the magnetotail, which closes magnetic flux and results in a "wedge" of closed flux which remains trapped, embedded in the magnetotail lobe. The cusp spot is an indicator of lobe reconnection at the high-latitude magnetopause; in its simplest case, lobe reconnection redistributes open flux without resulting in any net change in the open flux content of the magnetosphere. We present observations of the two phenomena interacting--i.e., a transpolar arc intersecting a cusp spot during part of its lifetime. The significance of this observation is that lobe reconnection can have the effect of opening closed magnetotail flux. We argue that such events should not be rare

Switching from an EFV-Based STR to a RPV-Based STR is Effective, Safe and Improves HIV Patients Health Status

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Origin of molecular oxygen in Comet 67P/Churyumov-Gerasimenko

Molecular oxygen has been detected in the coma of comet 67P/Churyumov-Gerasimenko with abundances in the 1-10% range by the ROSINA-DFMS instrument on board the Rosetta spacecraft. Here we find that the radiolysis of icy grains in low-density environments such as the presolar cloud may induce the production of large amounts of molecular oxygen. We also show that molecular oxygen can be efficiently trapped in clathrates formed in the protosolar nebula, and that its incorporation as crystalline ice is highly implausible because this would imply much larger abundances of Ar and N2 than those observed in the coma. Assuming that radiolysis has been the only O2 production mechanism at work, we conclude that the formation of comet 67P/Churyumov-Gerasimenko is possible in a dense and early protosolar nebula in the framework of two extreme scenarios: (1) agglomeration from pristine amorphous icy grains/particles formed in ISM and (2) agglomeration from clathrates that formed during the disk's cooling. The former scenario is found consistent with the strong correlation between O2 and H2O observed in 67P/C-G's coma while the latter scenario requires that clathrates formed from ISM icy grains that crystallized when entering the protosolar nebula.Comment: The Astrophysical Journal Letters, in pres

A multi-satellite study of accelerated ionospheric ion beams above the polar cap

This paper presents a study of nearly field-aligned outflowing ion beams observed on the Cluster satellites over the polar cap. Data are taken at geocentric radial distances of the order of 5–9 <i>R<sub>E</sub></i>. The distinction is made between ion beams originating from the polar cusp/cleft and beams accelerated almost along the magnetic field line passing by the spacecraft. Polar cusp beams are characterized by nearly field-aligned proton and oxygen ions with an energy ratio E<sub>O+</sub> / E<sub>H+</sub>, of the order of 3 to 4, due to the ion energy repartition inside the source and to the latitudinal extension of the source. Rapid variations in the outflowing ion energy are linked with pulses/modifications of the convection electric field. Cluster data allow one to show that these perturbations of the convection velocity and the associated ion structures propagate at the convection velocity. <P style="line-height: 20px;"> In contrast, polar cap local ion beams are characterized by field-aligned proton and oxygen ions with similar energies. These beams show the typical inverted V structures usually observed in the auroral zone and are associated with a quasi-static converging electric field indicative of a field-aligned electric field. The field-aligned potential drop fits well the ion energy profile. The simultaneous observation of precipitating electrons and upflowing ions of similar energies at the Cluster orbit indicates that the spacecraft are crossing the mid-altitude part of the acceleration region. In the polar cap, the parallel electric field can thus extend to altitudes higher than 5 Earth radii. A detailed analysis of the distribution functions shows that the ions are heated during their parallel acceleration and that energy is exchanged between H<sup>+</sup> and O<sup>+</sup>. Furthermore, intense electrostatic waves are observed simultaneously. These observations could be due to an ion-ion two-stream instability

Lipid profile changings after switching from rilpivirine/tenofovir disoproxil fumarate/emtricitabine to rilpivirine/tenofovir alafenamide/emtricitabine: different effects in different patients populations. Results from a large observational study

Tenofovir alafenamide (TAF) has similar efficacy compared to tenofovir disoproxil fumarate (TDF), but a less favorable effect on lipids. Aim of this study was to evaluate the impact on lipids of switching from rilpivirine (RPV)/ emtricitabine (FTC)/TDF to RPV/FTC/TAF in a large cohort of HIV-1 infected patients

Low-level viraemia, measured as viraemia copy-years, as a prognostic factor for medium–long-term all-cause mortality: a MASTER cohort study

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Lipid profile changings after switching from rilpivirine/tenofovir disoproxil fumarate/ emtricitabine to rilpivirine/tenofovir alafenamide/emtricitabine: Different effects in patients with or without baseline hypercholesterolemia

open10noTenofovir alafenamide (TAF) has similar efficacy compared to tenofovir disoproxil fumarate (TDF), but a less favorable effect on lipids. Aim of this retrospective multicentre study was to evaluate the impact on lipids of switching from rilpivirine (RPV)/ emtricitabine (FTC)/TDF to RPV/FTC/TAF in a cohort of HIV-1 infected patients. Total cholesterol (TC), high density lipoproteins (HDL) and low density lipoproteins (LDL) were compared at the moment of the switch and at the first following evaluation, by using paired t-test. Overall, 573 patients were considered, 99% with HIV-RNA <50 copies/ml, with mean age of 49.7 (±0.4) years and median 13.4 (6.9-22.5) years of HIV infection. In the study population with available data (431/573, 75%), mean TC changed from 173 ±1.7 to 188 ±1.8 mg/dl; mean HDL from 46 ±0.7 to 51± 0.7 mg/dl; mean LDL from 111 ±1.5 to 120 ±1.8 mg/dl (p<0.0001 for all). Neither LDL/HDL nor TC/HDL ratio changed significantly, with LDL/HDL from 2.6 ±0.5 to 2.5 ±0.5 (p = 0.12) and TC/HDL from 4.0 ±0.6 to 3.9 ±0.6 (p = 0.11). In patients with baseline diagnosis of hypercholesterolemia (TC>200 mg/dl, N = 87), there was no significant change in TC (224 ±2.2 to 228 ±3.4 mg/dl, p = 0.286) or LDL (150±2.5 to 151±3.2 mg/dl, p = 0.751), while HDL increased from 51 ±1.6 to 55 ±1.7 mg/dl (p<0.0001) and both LDL/HDL and TC/HDL ratio decreased significantly, from 3.2±0.1 to 3.0 ±0.1 (p = 0.025) and from 4.7±0.1 to 4.4 ±0.1 (p = 0.004). In this real life study, a slight increase in lipids was found after switching from RPV/FTC/TDF to RPV/FTC/TAF, but these results were not confirmed in people with hypercholesterolemia, in which lipids did not change and LDL/HDL and TC/HDL ratio decreased.openTaramasso L.; Di Biagio A.; Riccardi N.; Briano F.; Di Filippo E.; Comi L.; Mora S.; Giacomini M.; Gori A.; Maggiolo F.Taramasso, L.; Di Biagio, A.; Riccardi, N.; Briano, F.; Di Filippo, E.; Comi, L.; Mora, S.; Giacomini, M.; Gori, A.; Maggiolo, F

Dasabuvir and Ombitasvir/Paritaprevir/Ritonavir with or without Ribavirin in Patients with HIV-HCV Coinfection. Real Life Interim Analysis of an Italian Multicentre Compassionate Use Program

Background and Aims: An HCV cure is now possible in a large proportion of HIV-HCV patient. We present real life results of a compassionate use program promoted by SIMIT (Infectious and Tropical Diseases Italian Society) of Dasabuvir and Ombitasvir/Paritaprevir/Ritonavir ± Ribavirin for 12 weeks in 213 HIV-HCV genotype 1 patients. Data on efficacy and tolerability of this strategy in HIV patients have been reported until now only in 43 non cirrhotic HIV subjects

Time spent with HIV-RNA ≤ 200 copies/ml in a cohort of people with HIV during the U=U era

Objective: Zero risk of linked HIV transmission in sero-discordant couples when the HIV-infected partner had viral load (VL) <200 copies/mL (‘U status’) was found in observational studies. We aimed at estimating the proportion of time in which ‘U status’ was maintained and identifying factors associated with the risk of losing it. / Design: Observational cohort study. / Methods: We included participants in the ICONA cohort who had reached an established ‘U status’ (VL≤200 copies/mL for >6 months) as of December 2010. The outcome was the number of person-days of follow up (PDFU) above a VL>200 copies/ml, relative to the total number of PDFU observed. A logistic regression model was used to identify factors independently associated with the risk of losing ‘U status’. / Results: 8,241 persons living with HIV were included in the analysis who contributed 12,670,888 PDFU. Of these, 1,648 (20%) were female, 768 (9%) were people who inject drugs (PWID), and 2,066 (25%) were foreing-born. The median of VL measurements was 9 (IQR: 4–15). Overall, only 3.1% of PDFU were observed when VL was >200 copies/mL. The proportion of PDFU with VL>200 cp/ml was higher than average in females (5.3%), unemployed (5.4%), PWID (4.7%), and in people with>3 previous virologic failures (6.3%). These variables were significant predictors of losing ‘U status’ in the multivariable logistic regression. / Conclusions: Our results reinforce the validity of the U=U message in real-world setting. However, we identified subsets of our study population at higher risk of losing the ‘U status’ for whom additional efforts are needed