482 research outputs found
Seeing deconvolution of globular clusters in M31
Seeing deconvolution of surface-brightness profiles using the regularized multi-Gaussian method is potentially a powerful method for extraction of morphological information from digital images. Here we illustrate this method by applying it to CCD images of six globular clusters in M31. We demonstrate that it is possible to make some judgments about the dynamical structure of M31 globulars, using good-seeing, deconvolved CCD images obtained from the ground; for example, whether they have post-core-collapse morphology or not. The effective resolution limit of the method is about 0.1-0.3 arcsec, for the CCD images obtained in FWHM ≃ 1 arcsec seeing, and sampling of 0.3 arcsec/pixel. We also demonstrate the robustness of the method, i.e., its insensivity to the exact choices of the functional representation of the point-spread function, details of the deconvolution technique, etc. The situation is equivalent in terms of angular resolution and sampling to observing globular clusters in the Virgo Cluster (e.g., around M87) with the Hubble Space Telescope, and the methods demonstrated here may be applied to HST data in the future. Dynamical structure of globular clusters, e.g., propensity for the post-core-collapse morphology as a function of position in the host galaxy, reflects the global dynamical evolution of a globular cluster system, as was already demonstrated for our galaxy. Similar studies of large samples of globulars in M31 and other Local Group galaxies from the ground, and out to Virgo with the HST, can provide valuable insights about the mass distribution in galaxies, and the formation and evolution of their globular cluster systems. This pilot study is a step in this direction
On the Size Difference between Red and Blue Globular Clusters
Several recent studies have reported a mean size difference of about 20%
between the metal-rich and metal-poor subpopulations of globular clusters (GCs)
in a variety of galaxies. In this paper we investigate the possibility that the
size difference might be a projection effect, resulting from a correlation
between cluster size and galactocentric distance, combined with different
radial distributions of the GC subpopulations. We find that projection effects
may indeed account for a size difference similar to the observed one, provided
that there is a steep relation between GC size and galactocentric distance in
the central parts of the GC system and that the density of GCs flattens off
near the center in a manner similar to a King profile. For more centrally
peaked distributions, such as a de Vaucouleurs law, or for shallower
size-radius relations, projection effects are unable to produce the observed
differences in the size distributions.Comment: 30 pages, including 14 figures and 2 tables. Accepted for publication
in Ap
Intensive Care and Anesthesiology
AbstractThe wide range of medical disciplines afferent to anesthesiology (anesthesia, perioperative care, intensive care medicine, pain therapy, and emergency medicine), carry a great, cross-specialty opportunity to influence safety and quality of patients' care. Operating rooms and Intensive Care Units are settings burdened with a high risk of error: surgery is evolving, while the medical staff working in ICU is expected to provide high-quality care in a stressful and complex setting. It is estimated that about 1.5% of surgical interventions are complicated by critical events, but the true incidence is likely underestimated. Across medical specialties, preventable patient harm is more prevalent in the ICU.Recommendations and good practices for the safe provision of anesthesia and critical care exist and must be known and transferred into daily practice, since one of the main duties of anesthesia and critical care providers is to provide patient safety. Strategies to reduce the occurrence of medication errors, appropriate monitoring practices, equipment care and knowledge, planification and mastery of non-technical skills during emergencies, as well as designing and sustaining a healthy work environment and adopting adequate staffing policies could have an impact on patient safety and positively influence patient outcomes in this setting. The development of simulation training and cognitive aids (e.g., checklists, emergency manuals) is also changing the approach to crises and is expected to encourage a deeper cultural change
Vitamin d and the risk of non-melanoma skin cancer: A systematic literature review and meta-analysis on behalf of the italian melanoma intergroup
We aimed to provide a comprehensive overview of the link between vitamin D and non-melanoma skin cancer (NMSC). For this purpose, we conducted a systematic literature review (updated to 3 February 2021) and meta-analysis of the studies reporting on the association between vitamin D intake (from diet and supplements) and blood concentration, polymorphisms of the vitamin D receptor (VDR) and vitamin D binding protein (VDBP) genes, and the risk of NMSC. Random effects meta-analysis models were fitted to merge study-specific risk estimates into summary relative risk (SRR) and corresponding 95% confidence intervals (CI). Twenty-four studies altogether were included. There was a suggestive association between increasing serum/plasma vitamin D concentration and NMSC risk (SRR for highest vs. lowest concentration 1.67, 95%CI 0.61–4.56), although with large heterogeneity across studies (I2 = 91%). NMSC risk was associated with highest vitamin D intake in observational studies but not in clinical trials. Finally, there was no significant association between any polymorphism of the VDR and VDBP genes and NMSC risk. In conclusion, no strong relationship between vitamin D metabolism and NMSC risk appears to exist according to our systematic review and meta-analysis, although some findings are worthy of further investigation
Seeing deconvolution of globular clusters in M31
Seeing deconvolution of surface-brightness profiles using the regularized multi-Gaussian method is potentially a powerful method for extraction of morphological information from digital images. Here we illustrate this method by applying it to CCD images of six globular clusters in M31. We demonstrate that it is possible to make some judgments about the dynamical structure of M31 globulars, using good-seeing, deconvolved CCD images obtained from the ground; for example, whether they have post-core-collapse morphology or not. The effective resolution limit of the method is about 0.1-0.3 arcsec, for the CCD images obtained in FWHM ≃ 1 arcsec seeing, and sampling of 0.3 arcsec/pixel. We also demonstrate the robustness of the method, i.e., its insensivity to the exact choices of the functional representation of the point-spread function, details of the deconvolution technique, etc. The situation is equivalent in terms of angular resolution and sampling to observing globular clusters in the Virgo Cluster (e.g., around M87) with the Hubble Space Telescope, and the methods demonstrated here may be applied to HST data in the future. Dynamical structure of globular clusters, e.g., propensity for the post-core-collapse morphology as a function of position in the host galaxy, reflects the global dynamical evolution of a globular cluster system, as was already demonstrated for our galaxy. Similar studies of large samples of globulars in M31 and other Local Group galaxies from the ground, and out to Virgo with the HST, can provide valuable insights about the mass distribution in galaxies, and the formation and evolution of their globular cluster systems. This pilot study is a step in this direction
Development of Feline Immunodeficiency Virus ORF-A (tat) Mutants: In Vitro and in Vivo Characterization
AbstractA functional ORF-A is essential for efficient feline immunodeficiency virus replication in lymphocytes. We have characterized a series of mutants of the Petaluma strain, derived from p34TF10 and having different combinations of stop codons and increasingly long deletions in ORF-A. Six clones proved fully replicative in fibroblastoid Crandell feline kidney cells and monocyte-derived macrophage cultures but failed to replicate in T cell lines and primary lymphoblasts. Cats inoculated with three selected mutants had considerably milder infections than controls given intact ORF-A virus. In vivo, the mutants maintained growth properties similar to those in vitro for at least 7 months, except that replication in lymphoid cells was strongly reduced but not ablated. One mutant underwent extensive ORF-A changes without, however, reverting to wild-type. Antiviral immune responses were feeble in all cats, suggesting that viral loads were too low to represent a sufficiently powerful antigenic stimulus
Heart and Lungs in COPD. Close friends in real life - separate in daily medical practice?
Chronic obstructive pulmonary disease (COPD) is associated with a 2-3 times higher rate of cardiovascular disorders (CVD) which is independent of other risk factors. A low FEV1 is a specific predictor of mortality as a result of cardiac causes, even stronger than increased cholesterol: for each 10% reduction of FEV1, cardiovascular mortality increases by 28%. The main causes of death among COPD patients are of cardiovascular origin. COPD and CVD have two major risk factors in common - advanced age and tobacco smoking. The search for a pathogenetic link between the two conditions focuses mainly on systemic extension of pulmonary inflammation. Despite such a frequent association, pulmonologists and cardiologists in both the clinical and the research settings often underestimate the importance of a correct diagnosis and severity stratification of the two combined conditions. Spirometry, in particular, is largely underprescribed. Missed diagnosis and severity stratification, incomplete knowledge of adverse drug events and lack of resources lead to undertreatment of patients combining COPD and CVD, and in particular, the underuse of beta-blockers, inhaled bronchodilators and rehabilitation. Clinical studies focusing on this group of patients should be promoted in the future to test therapies and manage options. Furthermore, efforts must be made to improve the present standards of care, which falls short of recommended levels, starting from the often-neglected use of spirometry to confirm a diagnosis of COPD
Dietary total antioxidant capacity and colorectal cancer in the Italian EPIC cohort
Background
Colorectal cancer is the third most common cancer worldwide. Diet has been hypothesized as involved in colorectal cancer etiology, but few studies on the influence of total dietary antioxidant intake on colorectal cancer risk have been performed.
Methods
We investigated the association between colorectal cancer risk and the total antioxidant capacity (TAC) of the diet, and also of intake of selected antioxidants, in 45,194 persons enrolled in 5 centers (Florence, Naples, Ragusa, Turin and Varese) of the European Prospective
Investigation into Cancer and Nutrition (EPIC) Italy study. TAC was estimated by the Trolox equivalent antioxidant capacity (TEAC) assay. Hazard ratios (HRs) for developing colorectal cancer, and colon and rectal cancers separately, adjusted for confounders, were estimated for tertiles of TAC by Cox modeling, stratifying by center.
Results
Four hundred thirty-six colorectal cancers were diagnosed over a mean follow-up of 11.28 years. No significant association between dietary TAC and colorectal cancer incidence was found. However for the highest category of TAC compared to the lowest, risk of developing colon cancer was lower (HR: 0.63; 95% CI: 0.44\u20130.89, P trend: 0.008). By contrast, increasing TAC intake was associated with significantly increasing risks of rectal cancer (2nd tertile HR: 2.09; 95%CI: 1.19\u20133.66; 3rd tertile 2.48 95%CI: 1.32\u20134.66; P trend 0.007). Intakes of
vitamin C, vitamin E, and
f-carotene were not significantly associated with colorectal cancer risk. Conclusions
Further prospective studies are needed to confirm the contrasting effects of high total antioxidant intake on risk of colon and rectal cancers
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