The Resolved Outer Population of NGC6822 with WFPC2

We present F336W (U), F439W (B), F555W (V), and F675W (R) Wide Field Planetary Camera 2 (WFPC2) photometry of two outer regions of the Local Group dwarf irregular galaxy NGC6822. The NE region is ~13 arcmin from the galaxy centre, while the W region lies 10 arcmin out, and within the wispy low surface brightness outer regions of the galaxy. The fields are not crowded and contain few NGC 6822 stars. We discuss errors and uncertainties and find that the W region contains a main sequence that extends to stars of about 2 solar masses, with an age of about 200 Myr. The NE region has no main sequence or stars younger than 1 Gyr, but does contain some luminous red stars that are not matched in the W field. These stars are not clumped in the field. The results suggest that the W region may be a trace of a tidal event that triggered the current star-formation in this isolated galaxy.Comment: 12 pages including 2 tables, plus 4 figures (#1 omitted) To appear in PAS

Identifying short motifs by means of extreme value analysis

The problem of detecting a binding site -- a substring of DNA where transcription factors attach -- on a long DNA sequence requires the recognition of a small pattern in a large background. For short binding sites, the matching probability can display large fluctuations from one putative binding site to another. Here we use a self-consistent statistical procedure that accounts correctly for the large deviations of the matching probability to predict the location of short binding sites. We apply it in two distinct situations: (a) the detection of the binding sites for three specific transcription factors on a set of 134 estrogen-regulated genes; (b) the identification, in a set of 138 possible transcription factors, of the ones binding a specific set of nine genes. In both instances, experimental findings are reproduced (when available) and the number of false positives is significantly reduced with respect to the other methods commonly employed.Comment: 6 pages, 5 figure

Evolution of the disc atmosphere in the X-ray binary MXB 1659-298, during its 2015-2017 outburst

We report on the evolution of the X-ray emission of the accreting neutron star (NS) low mass X-ray binary (LMXB), MXB 1659-298, during its most recent outburst in 2015-2017. We detected 60 absorption lines during the soft state (of which 21 at more than 3 $\sigma$), that disappeared in the hard state (e.g., the Fe xxv and Fe xxvi lines). The absorbing plasma is at rest, likely part of the accretion disc atmosphere. The bulk of the absorption features can be reproduced by a high column density ($log(N_H/cm^{-2})\sim23.5$) of highly ionised ($log(\xi/erg~cm~s^{-1})\sim3.8$) plasma. Its disappearance during the hard state is likely the consequence of a thermal photo-ionisation instability. MXB 1659-298's continuum emission can be described by the sum of an absorbed disk black body and its Comptonised emission, plus a black body component. The observed spectral evolution with state is in line with that typically observed in atoll and stellar mass black hole LMXB. The presence of a relativistic Fe K$\alpha$ disk-line is required during the soft state. We also tentatively detect the Fe xxii doublet, whose ratio suggests an electron density of the absorber of $n_e>10^{13} cm^{-3}$, hence, the absorber is likely located at $<7\times10^4 r_g$ from the illuminating source, well inside the Compton and outer disc radii. MXB 1659-298 is the third well monitored atoll LMXB showcasing intense Fe xxv and Fe xxvi absorption during the soft state that disappears during the hard state.Comment: MNRAS in pres

Noxiousness of the african white stem borer, Maliarpha separatella Rag (Pyralidae: Phycitinae) in irrigated paddy fields at lake Alaotra (Madagascar)

A study of the noxiousness of the African white rice stem borer, Maliarpha separatella Rag carried out under controlled field conditions has revealed that the impact of this pest on the yield and its components is assessable. For mean infestation rates up to 68% during the period of highest sensitivity of a paddy rice culture (second half of tillering to panicle initiation), no significant decrease could be observed in the number of panicles, nor any significant increase in the number of white heads and the number of empty grains per hill. However, with increasing infestation rates, the number of immature panicles increased and the number and weight of filled grains per hill decreased. An explorative analysis of the infestation rate-yield loss relationship, showed that a sigmoid model describes this interdependence appropriately. The proposed economic injury level (EIL), is here considered more the result of an approach, which had as its goal the re-definition of the status of the pest than as an instrument of a chemical control programme with treatments based on an action threshol

Simplifying instanton corrections to N=4 SYM correlators

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited

Experimental analysis on the effects of DC arc discharges at various flow regimes

This paper addresses the control of the boundary layer on a compression ramp by means of DC electrical arc discharges. The development and realization of the control system are first described and then assessed in the wind tunnel. The objective of the research was to control the supersonic flow using the minimum amount of energy. The array of electrodes was located at the base of a ramp, where a low momentum flow develops. The electrical discharge was generated by a custom designed electronic facility based on high-voltage ignition coils. The slanted tungsten electrodes were insulated by mounting them in a ceramic support. The discharge evolution was studied through high-speed flow visualizations, while electrical measurements at the high-voltage section of the circuitry allowed to estimate the energy release. The development of a high-speed short exposure Schlieren imaging technique, based on a very short duration laser pulse illumination and a double shot CCD camera, allowed to observe the macroscopic effects associated with the arc establishment between the electrodes (glow, sound wave and heat release). Due to the long residence time, the thermal perturbation spread along the streamwise direction. Cross correlation of Schlieren images with short time separation revealed that in supersonic conditions, the discharges led to an overall acceleration of the flow field underneath the oblique shock wave

Cytotoxic Effects of Hexavalent and Trivalent Chromium on Mammalian Cells In Vitro

The cytotoxic effects of hexavalent (k2Cr2O7) and trivalent (CrCl3) chromium compounds have been studied in cultured hamster fibroblasts (BHK line) and human epithelial-like cells (HEp line)

Long-term subjective outcomes of barbed reposition pharyngoplasty for obstructive sleep apnea syndrome treatment

Background: The purpose of this study was to evaluate long-term subjective outcomes of barbed reposition pharyngoplasty for obstructive sleep apnea syndrome (OSAS) treatment using a specific questionnaire, the Palate Postoperative Problem Score (PPOPS). Methods: 140 patients who underwent barbed reposition pharyngoplasty (BRP) surgery in the Morgagni Pierantoni Hospital of Forlì, Italy were enrolled in the study. Postoperative outcomes were evaluated in a short- and long-term follow-up using the PPOPS questionnaire. The average period of follow-up was 26 months. All patients received the PPOPS questionnaire by telephone in a period between April and August 2019. Results: 51% of patients complained of swallowing problems after surgery. In 91% of cases, the problem cleared up spontaneously. At the time of the interview, only 9% of patients had a residual swallowing difficult. At the time of PPOPS evaluation, rhinolalia was observed in 8% of patients, whereas nose regurgitation was present in 2% of patients. In 20% of patients, the foreign body sensation was present during follow-up. The value of apnea-hypopnea index (AHI) reduced from the preoperative value of 31.5 to the postoperative value of 11.4. Conclusions: BRP surgery proved to be an effective technique, appreciated by the majority of patients. Use of the PPOPS questionnaire has demonstrated that the BRP technique seems to ensure efficacy and lower morbidity, with few complications after surgery