Cepheid theoretical models and observations in HST/WFC3 filters: the effect on the Hubble constant Ho

We present a complete theoretical scenario for classical Cepheids in the most commonly used HST/WFC3 filters, going from optical (F555W, F606W and F814W) to near-infrared (F160W) bands. The importance of such a study is related to the recent release of new classical Cepheids observed with HST/WFC3 in 8 distant galaxies where SNIa are hosted. These observations have posed sound constraints to the current distance scale with uncertainties on the Hubble constant Ho smaller than 3%. Our models explore a large range of metallicity and Helium content, thus providing a robust and unique theoretical tool for describing these new and future HST/WFC3 observations. As expected, the Period-Luminosity (PL) relation in F160W filter is linear and slightly dependent on the metallicity when compared with optical bands, thus it seems the most accurate tool to constrain extragalactic distances with Cepheids. We compare the pulsation properties of Cepheids observed with HST/WFC3-IR with our theoretical scenario and we discuss the agreement with the predicted Instability Strip for all the investigated galaxy samples including the case of NGC4258. Finally, adopting our theoretical F160W PL relation for Z=0.02 and log P>1.0, we derive new distance moduli. In particular, for NGC 4258, we derive a distance modulus mu0 = 29.345 +- 0.004 mag with a sigma = 0.34 mag, which is in very good agreement with the geometrical maser value. Moreover, using the obtained distance moduli, we estimate the Hubble constant value, Ho=76.0 +- 1.9 km s-1 Mpc-1 in excellent agreement with the most recent literature values.Comment: 13 pages, 9 figures, 4 tables, MNRAS, accepte

Secure self-calibrating quantum random bit generator

Random bit generators (RBGs) are key components of a variety of information processing applications ranging from simulations to cryptography. In particular, cryptographic systems require "strong" RBGs that produce high-entropy bit sequences, but traditional software pseudo-RBGs have very low entropy content and therefore are relatively weak for cryptography. Hardware RBGs yield entropy from chaotic or quantum physical systems and therefore are expected to exhibit high entropy, but in current implementations their exact entropy content is unknown. Here we report a quantum random bit generator (QRBG) that harvests entropy by measuring single-photon and entangled two-photon polarization states. We introduce and implement a quantum tomographic method to measure a lower bound on the "min-entropy" of the system, and we employ this value to distill a truly random bit sequence. This approach is secure: even if an attacker takes control of the source of optical states, a secure random sequence can be distilled.Comment: 5 pages, 2 figure

TOXICITY OF PREDNISOLONE, DEXAMETHASONE AND THEIR PHOTOCHEMICAL DERIVATIVES ON AQUATIC ORGANISMS

Light exposure of aqueous suspensions of prednisolone and dexamethasone causes their partial phototransformation. The photoproducts, isolated by chromatographic techniques, have been identified by spectroscopic means. Prednisolone, dexamethasone and their photoproducts have been tested to evaluate their acute and chronic toxic effects on some freshwater chain organisms. The rotifer Brachionus calyciflorus and the crustaceans Thamnocephalus platyurus and Daphnia magna were chosen to perform acute toxicity tests, while the alga Pseudokircheneriella subcapitata (formerly known as Selenastrum capricornutum) and the crustacean Ceriodaphnia dubia to perform chronic tests. The photochemical derivatives are more toxic than the parent compounds. Generally low acute toxicity was found. Chronic exposure to this class of pharmaceuticals caused inhibition of growth population on the freshwater crustacean C. dubia while the alga P. subcapitata seems to be less affected by the presence of these drugs

The Ecoremed protocol for an integrated agronomic approach to characterization and remediation of contaminated soils

Definition of a site as contaminated: Problems related to agricultural soils Massimo Fagnano.......... pp. 1-5 Geography of soil contamination for characterization and precision remediation of potentially contaminated sites Giuliano Langella, Antonietta Agrillo, Angelo Basile, Roberto De Mascellis, Piero Manna, Pierpaolo Moretti, Florindo Antonio Mileti, Fabio Terribile, Simona Vingiani.......... pp. 6-15 Assessing the bioavailability of potentially toxic elements in soil: A proposed approach Claudia Rocco, Diana Agrelli, Maria Tafuro, Antonio Giandonato Caporale, Paola Adamo.......... pp. 16-22 Use of the native vascular flora for risk assessment and management of an industrial contaminated soil Donato Visconti, Nunzio Fiorentino, Adriano Stinca, Ida Di Mola, Massimo Fagnano.......... pp. 23-33 Assisted phytoremediation for restoring soil fertility in contaminated and degraded land Nunzio Fiorentino, Mauro Mori, Vincenzo Cenvinzo, Luigi Giuseppe Duri, Laura Gioia, Donato Visconti, Massimo Fagnano.......... pp. 34-44 Bioassays for evaluation of sanitary risks from food crops cultivated in potentially contaminated sites Luigi Giuseppe Duri, Nunzio Fiorentino, Eugenio Cozzolino, Lucia Ottaiano, Diana Agrelli Massimo Fagnano.......... pp. 45-52 Responses of bacterial community structure and diversity to soil eco-friendly bioremediation treatments of two multi-contaminated fields Valeria Ventorino, Vincenza Faraco, Ida Romano, Olimpia Pepe.......... pp. 53-58 Monitoring and modelling the role of phytoremediation to mitigate non-point source cadmium pollution and groundwater contamination at field scale Mario Palladino, Paolo Nasta, Alessandra Capolupo, Nunzio Romano.......... pp. 59-6

Heralding Single Photons Without Spectral Factorability

Recent efforts to produce single photons via heralding have relied on creating spectrally factorable two-photon states in order to achieve both high purity and high production rate. Through a careful multimode analysis, we find, however, that spectral factorability is not necessary. Utilizing single-mode detection, a similar or better performance can be achieved with non-factorable states. This conclusion rides on the fact that even when using a broadband filter, a single-mode measurement can still be realized, as long as the coherence time of the triggering photons exceeds the measurement window of the on/off detector.Comment: 7 pages, 5 figure

Association between noninvasive fibrosis markers and cardio-vascular organ damage among adults with hepatic steatosis

Evidence suggests that advanced fibrosis, as determined by the noninvasive NAFLD fibrosis score (NFS), is a predictor of cardiovascular mortality in individuals with ultrasonography-diagnosed NAFLD. Whether the severity of histology (i.e., fibrosis stage) is associated with more pronounced cardiovascular organ damage is unsettled. In this study, we analyzed the clinical utility of NFS in assessing increased carotid intima-media thickness (cIMT), and left ventricular mass index (LVMI). In this cross-sectional study NFS, cIMT and LVMI were assessed in 400 individuals with ultrasonography-diagnosed steatosis. As compared with individuals at low probability of liver fibrosis, individuals both at high and at intermediate probability of fibrosis showed an unfavorable cardio-metabolic risk profile having significantly higher values of waist circumference, insulin resistance, high sensitivity C-reactive protein (hsCRP), fibrinogen, cIMT, and LVMI, and lower insulin-like growth factor-1 (IGF-1) levels. The differences in cIMT and LVMI remained significant after adjustment for smoking and metabolic syndrome. In a logistic regression model adjusted for age, gender, smoking, and diagnosis of metabolic syndrome, individuals at high probability of fibrosis had a 3.9-fold increased risk of vascular atherosclerosis, defined as cIMT.0.9 mm, (OR 3.95, 95% CI 1.12–13.87) as compared with individuals at low probability of fibrosis. Individuals at high probability of fibrosis had a 3.5-fold increased risk of left ventricular hypertrophy (LVH) (OR 3.55, 95% CI 1.22–10.34) as compared with individuals at low probability of fibrosis. In conclusion, advanced fibrosis, determined by noninvasive fibrosis markers, is associated with cardiovascular organ damage independent of other known factors

Agronomic approaches for the remediation of contaminated soils

Contaminated soils can only be efficiently managed if proper procedures are adopted for evaluating the risks due to contamination as well as the actual volume of contaminated soil [...

Blue Straggler masses from pulsation properties. I. The case of NGC6541

We used high-spatial resolution images acquired with the WFC3 on board HST to probe the population of variable blue straggler stars in the central region of the poorly studied Galactic globular cluster NGC 6541. The time sampling of the acquired multi wavelength (F390W, F555W and F814W) data allowed us to discover three WUma stars and nine SX Phoenicis. Periods, mean magnitudes and pulsation modes have been derived for the nine SX Phoenicis and their masses have been estimated by using pulsation equations obtained from linear non adiabatic models. We found masses in the range 1.0-1.1Mo, with an average value of 1.06+-0.09 Mo (sigma = 0.04), significantly in excess of the cluster Main Sequence Turn Off mass (~ 0.75Mo). A mild trend between mass and luminosity seems also to be present. The computed pulsation masses turn out to be in very good agreement with the predictions of evolutionary tracks for single stars, indicating values in the range ~ 1.0-1.2 Mo for most of the BSS population, in agreement with what discussed in a number of previous studies.Comment: 8 pages, 9 figures, ApJ, accepte

On the central helium-burning variable stars of the LeoI dwarf spheroidal galaxy

We present a study of short period, central helium-burning variable stars in the Local Group dwarf spheroidal galaxy LeoI, including 106 RR Lyrae stars and 51 Cepheids. So far, this is the largest sample of Cepheids and the largest Cepheids to RR Lyrae ratio found in such a kind of galaxy. The comparison with other Local Group dwarf spheroidals, Carina and Fornax, shows that the period distribution of RR Lyrae stars is quite similar, suggesting similar properties of the parent populations, whereas the Cepheid period distribution in LeoI peaks at longer periods (P \sim 1.26d instead of ~0.5d) and spans over a broader range, from 0.5 to 1.78d. Evolutionary and pulsation predictions indicate, assuming a mean metallicity peaked within -1.5<= [Fe/H]<=-1.3, that the current sample of LeoI Cepheids traces a unique mix of Anomalous Cepheids (blue extent of the red--clump, partially electron degenerate central helium-burning stars) and short-period classical Cepheids (blue-loop, quiescent central helium-burning stars). Current evolutionary prescriptions also indicate that the transition mass between the two different groups of stars is MHeF \sim 2.1 Mo, and it is constant for stars metal-poorer than [Fe/H]\sim-0.7. Finally, we briefly outline the different implications of the current findings on the star formation history of LeoI.Comment: 5 Pages, 4 Figures, ApJ letter, accepte

Strong low-frequency quantum correlations from a four-wave mixing amplifier

We show that a simple scheme based on nondegenerate four-wave mixing in a hot atomic vapor behaves like a near-perfect phase-insensitive optical amplifier, which can generate bright twin beams with a measured quantum noise reduction in the intensity difference of more than 8 dB, close to the best optical parametric amplifiers and oscillators. The absence of a cavity makes the system immune to external perturbations, and the strong quantum noise reduction is observed over a large frequency range.Comment: 4 pages, 4 figures. Major rewrite of the previous version. New experimental results and further analysi