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Context. Blue stragglers stars (BSSs) are thought to form in globular clusters by two main formation channels: $i)$mergers induced by stellar collisions; and $ii)$coalescence or mass transfer between companions in binary systems. The detailed study of the BSS properties is therefore crucial for understanding the binary evolution mechanisms and the complex interplay between dynamics and stellar evolution in dense stellar systems.

Aims.We present a 900 s, wide-field Uimage of the inner region of the Andromeda galaxy obtained during the commissioning of the blue channel of the Large Binocular Camera mounted on the prime focus of the Large Binocular Telescope.

Context. Deep multicolour surveys are the main tool for exploring the formation and evolution of the very faint galaxies that are beyond the spectroscopic limit of present technology. The photometric properties of these faint galaxies are usually compared with current renditions of semianalytical models to provide constraints on the detailed treatment of the fundamental physical processes involved in galaxy formation and evolution, namely the mass assembly and the star formation.Aims. Galaxy counts over large sky areas in the 360?nm near-UV band are particularly difficult to obtain given the low efficiency of near-UV instrumentation, even at 8?m class telescopes. Observing in the near-UV bands can provide a first assessment of the distribution of star formation activity in distant (up to z ~ 3) galaxies. A relatively large instrumental field of view helps to minimize the biases caused by cosmic variance.Methods. We obtained deep images in the 360?nm U band provided by the blue channel of the Large Binocular Camera at the prime focus of the Large Binocular Telescope. Over an area of ?0.4 sq. deg., we derived the galaxy number counts down to U = 27 in the Vega system (corresponding to U = 27.86 in the AB system) at a completeness level of 30% reaching the faintest current limit for this wavelength and sky area.Results. The shape of the galaxy number counts in the U band can be described by a double power-law, the bright side being consistent with the shape of shallower surveys of comparable or greater areas. The slope bends over significantly at U > 23.5 ensuring the convergence of the contribution by star-forming galaxies to the extragalactic background light in the near-UV band to a value that is more than 70% of the most recent upper limits derived for this band. We jointly compared our near-UV and K band counts collected from the literature with a few selected hierarchical CDM models, concentrating on specific critical issues in the physical description of the galaxy formation and evolution.

Aims. We present the characteristics and some early scientific results of the first instrument at the Large Binocular Telescope (LBT), the Large Binocular Camera (LBC). Each LBT telescope unit will be equipped with similar prime focus cameras. The blue channel is optimized for imaging in the UV-B bands and the red channel for imaging in the VRIz bands. The corrected field-of-view of each camera is approximately 30?arcmin in diameter, and the chip area is equivalent to a 23?23?arcmin2field. In this paper we also present the commissioning results of the blue channel. Methods. The scientific and technical performance of the blue channel was assessed by measurement of the astrometric distortion, flat fielding, ghosts, and photometric calibrations. These measurements were then used as input to a data reduction pipeline applied to science commissioning data. Results. The measurements completed during commissioning show that the technical performance of the blue channel is in agreement with original expectations. Since the red camera is very similar to the blue one we expect similar performance from the commissioning that will be performed in the following months in binocular configuration. Using deep UV image, acquired during the commissioning of the blue camera, we derived faint UV galaxy-counts in a ~ 500?sq. arcmin sky area to U(Vega) = 26.5. These galaxy counts imply that the blue camera is the most powerful UV imager presently available and in the near future in terms of depth and extent of the field-of-view. We emphasize the potential of the blue camera to increase the robustness of the UGR multicolour selection of Lyman break galaxies at redshift z ~ 3.

A number of multimedia and process control applications can take advantage from the ability to adapt soft real-time load to available computational capacity. This capability is required, for example, to react to changed operating conditions as well as to ensure graceful degradation of an application under transient overloads. In this paper, we illustrate a novel adaptive scheduling technique based on rate modulation of a set of periodic tasks in a range of admissible rates. By casting constraints on rate ranges in a linear programming formulation, several adaptation policies can be considered, along with additional constraints reflecting various application requirements. The paper investigates the effectiveness of rate modulation strategies both on simulated task sets and on real experiments.

Background & Aims: Capsule endoscopy (CE) is a promising diagnostic tool for the study of patients with obscure gastrointestinal bleeding. However, the diagnostic yield of this technique has not been adequately studied. We evaluated sensitivity and specificity of CE and the outcome after CE in patients with obscure gastrointestinal bleeding. Methods:One hundred consecutive patients (all with recent negative upper and lower endoscopy; 26 with ongoing overt bleeding [group A], 31 with previous overt bleeding [group B], and 43 with guaiac-positive stools and iron-deficiency anemia [group C]) underwent CE. Results: The yield of positive findings on CE was 92.3% in group A, 12.9% in group B, and 44.2% in group C (P < 0.0001, A vs. B, A vs. C). Angiodysplasia (29%) and Crohn's disease (6%) were the most common diagnoses. Sensitivity, specificity, and positive and negative predictive values of CE were 88.9%, 95%, 97%, and 82.6%, respectively. CE results led to treatments resolving the bleeding in 86.9% of patients undergoing the procedure while actively bleeding. Capsule retention because of unsuspected stenosis occurred in 5 patients and required surgery, which resolved the clinical problem, in 4 patients. Conclusions:CE is an effective diagnostic tool for patients with obscure GI bleeding. The best candidates for the procedure are those with ongoing obscure-overt bleeding or with obscure-occult bleeding. If done early in the course of the workup, CE could shorten considerably the time to diagnosis, lead to definitive treatment in a relevant proportion of patients, and spare a number of alternative investigations with low diagnostic yield.

In some uncontrolled studies, a high prevalence of Helicobacter pyloriinfection unexpectedly has been found in patients with colorectal cancer. The purpose of the study was to investigate the prevalence of H. pyloriinfection in patients with colonic polyps or cancer. We reviewed 50 consecutive patients with either colonic adenomas or cancer who entered a preliminary case-control study. For each patient, 2 age- and gender-matched control subjects were selected (72 males; mean age, 63.1 years). A further 44 consecutive patients (30 with polyps and 14 with cancer) subsequently were enrolled. The H. pyloriprevalence in patients with either polyps or cancer was compared with that in control subjects. Anti-H. pyloriimmunoglobulin G antibodies were assayed by an immunoenzymatic method. The prevalence of H. pyloriantibodies was 49 (49%) of 100 in control subjects, 40 (71.4%) of 56 in patients with polyps (p < 0.006 vs. control subjects), and 21 (55%) of 38 in patients with cancer (not significant). Among patients with colorectal cancer, H. pyloriprevalence was 9 (69.2%) of 13 for patients evaluated at the time of diagnosis and 12 (48%) of 25 for patients evaluated 1 to 9 years after surgery.

We present a detailed study of the dwarf galaxy VV124 (UGC4879), recently recognized as a remarkably isolated member of the Local Group. We have obtained deep (r≃ 26.5) wide-field (23′ × 23′) g,r photometry of individual stars with the LBC camera at the Large Binocular Telescope under sub-arcsec seeing conditions. The color–magnitude diagram suggests that the stellar content of the galaxy is dominated by an old, metal-poor population, with a significant metallicity spread. A very clean detection of the RGB tip allows us to derive an accurate distance of D= 1.3 ± 0.1 Mpc. Combining surface photometry with star counts, we are able to trace the surface brightness profile of VV124 out to  ~5′ ≃ 1.9 kpc radius (where μr≃ 30 mag/arcsec2), showing that it is much more extended than previously believed. Moreover, the surface density map reveals the presence of two symmetric flattened wings emanating from the central elongated spheroid and aligned with its major axis, resembling a stellar disk seen nearly edge-on. We also present H iobservations obtained with the Westerbork Synthesis Radio Telescope (WSRT), the first ever of this object. A total amount of  ≃ 106M⊙of H igas is detected in VV124. Compared to the total luminosity, this gives a value of MHI/LV= 0.11, which is particularly low for isolated Local Group dwarfs. The spatial distribution of the gas does not correlate with the observed stellar wings. The systemic velocity of the H iin the region superposed to the stellar main body of the galaxy is Vh=  −25 km s-1. The velocity field shows substructures typical of galaxies of this size but no sign of rotation. The H ispectra indicates the presence of a two-phase interstellar medium, again typical of many dwarf galaxies.