3,630 research outputs found

    The supermassive black hole mass - S\'ersic index relations for bulges and elliptical galaxies

    Full text link
    Scaling relations between supermassive black hole mass, M_BH, and host galaxy properties are a powerful instrument for studying their coevolution. A complete picture involving all of the black hole scaling relations, in which each relation is consistent with the others, is necessary to fully understand the black hole-galaxy connection. The relation between M_BH and the central light concentration of the surrounding bulge, quantified by the S\'ersic index n, may be one of the simplest and strongest such relations, requiring only uncalibrated galaxy images. We have conducted a census of literature S\'ersic index measurements for a sample of 54 local galaxies with directly measured M_BH values. We find a clear M_BH - n relation, despite an appreciable level of scatter due to the heterogeneity of the data. Given the current M_BH - L_sph and the L_sph - n relations, we have additionally derived the expected M_BH - n relations, which are marginally consistent at the 2 sigma level with the observed relations. Elliptical galaxies and the bulges of disc galaxies are each expected to follow two distinct bent M_BH - n relations due to the S\'ersic/core-S\'ersic divide. For the same central light concentration, we predict that M_BH in the S\'ersic bulges of disc galaxies are an order magnitude higher than in S\'ersic elliptical galaxies if they follow the same M_BH - L_sph relation.Comment: 12 pages, 6 figures, 5 tables, accepted for publication in MNRA

    High-precision RF voltage measurements using longitudinal phase-space tomography in CERN PSB and SPS

    Full text link
    Precisely determining the gap voltage and phase in an RF cavity is essential for the calibration of the LLRF feedbacks. Following the conventional approach, measured RF power is converted into gap voltage, assuming a given shunt impedance. However, power and impedance evaluations can both have large uncertainties. Alternatively, the voltage can be obtained precisely with a technique based on longitudinal phase-space tomography. From a set of bunch profiles, tomography reconstructs the bunch distribution in the longitudinal phase-space. The quality of the reconstruction strongly depends on the RF voltage and therefore allows to derive its absolute value. In this paper we describe the tomography-based voltage measurements performed in the CERN PSB and SPS, where this method allowed to detect significant voltage errors for the main RF systems. After applying the correction factors in the LLRF, 1\% accuracies were reached. We report here also the remarkable results achieved by using this technique to calibrate the voltage of the SPS higher-harmonic cavities at 800 MHz, as well as their relative phases with respect to the 200 MHz cavities.Comment: Talk presented at LLRF Workshop 2023 (LLRF2023, arXiv: 2310.03199

    Challenges recruiting to a proof-of-concept pharmaceutical trial for a rare disease: The trigeminal neuralgia experience

    Get PDF
    Background: This study aimed to describe recruitment challenges encountered during a phase IIa study of vixotrigine, a state and use-dependent Nav1.7 channel blocker, in individuals with trigeminal neuralgia. Methods: This was an international, multicenter, placebo-controlled, randomized withdrawal study that included a 7-day run-in period, a 21-day open-label phase, and a 28-day double-blind phase in which patients (planned n = 30) were randomized to vixotrigine or placebo. Before recruitment, all antiepileptic drugs had to be stopped, except for gabapentin or pregabalin. After the trial, patients returned to their original medications. Patient recruitment was expanded beyond the original five planned (core) centers in order to meet target enrollment (total recruiting sites N = 25). Core sites contributed data related to patient identification for study participation (prescreening data). Data related to screening failures and study withdrawal were also analyzed using descriptive statistics. Results: Approximately half (322/636; 50.6%) of the patients who were prescreened at core sites were considered eligible for the study and 56/322 (17.4%) were screened. Of those considered eligible, 26/322 (8.1%) enrolled in the study and 6/322 (1.9%) completed the study. In total, 125 patients were screened across all study sites and 67/125 (53.6%) were enrolled. At prescreening, reasons for noneligibility varied by site and were most commonly diagnosis change (78/314; 24.8%), age > 80 years (75/314; 23.9%), language/distance/mobility (61/314; 19.4%), and noncardiac medical problems (53/314; 16.9%). At screening, frequently cited reasons for noneligibility included failure based on electrocardiogram, insufficient pain, and diagnosis change. Conclusions: Factors contributing to recruitment challenges encountered in this study included diagnosis changes, anxiety over treatment changes, and issues relating to distance, language, and mobility. Wherever possible, future studies should be designed to address these challenges. Trial registration: ClinicalTrials.gov, NCT01540630. EudraCT, 2010-023963-16. 07 Aug 2015

    Addressing Patient Safety Hazards Using Critical Incident Reporting in Hospitals: A Systematic Review

    Get PDF
    Critical incident reporting systems (CIRS) are in use worldwide. They are designed to improve patient care by detecting and analyzing critical and adverse patient events and by taking corrective actions to prevent reoccurrence. Critical incident reporting systems have recently been criticized for their lack of effectiveness in achieving actual patient safety improvements. However, no overview yet exists of the reported incidents' characteristics, their communication within institutions, or actions taken either to correct them or to prevent their recurrence. Our main goals were to systematically describe the reported CIRS events and to assess the actions taken and their learning effects. In this systematic review of studies based on CIRS data, we analyzed the main types of critical incidents (CIs), the severity of their consequences, their contributing factors, and any reported corrective actions.; Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we queried MEDLINE, Embase, CINAHL, and Scopus for publications on hospital-based CIRS. We classified the consequences of the incidents according to the National Coordinating Council for Medication Error Reporting and Prevention index, the contributing factors according to the Yorkshire Contributory Factors Framework and the Human Factors Classification Framework, and all corrective actions taken according to an action hierarchy model on intervention strengths.; We reviewed 41 studies, which covered 479,483 CI reports from 212 hospitals in 17 countries. The most frequent type of incident was medication related (28.8%); the most frequent contributing factor was labeled "active failure" within health care provision (26.1%). Of all professions, nurses submitted the largest percentage (83.7%) of CI reports. Actions taken to prevent future CIs were described in 15 studies (36.6%). Overall, the analyzed studies varied considerably regarding methodology and focus.; This review of studies from hospital-based CIRS provides an overview of reported CIs' contributing factors, characteristics, and consequences, as well as of the actions taken to prevent their recurrence. Because only 1 in 3 studies reported on corrective actions within the healthcare facilities, more emphasis on such actions and learnings from CIRS is required. However, incomplete or fragmented reporting and communication cycles may additionally limit the potential value of CIRS. To make a CIRS a useful tool for improving patient safety, the focus must be put on its strength of providing new qualitative insights in unknown hazards and also on the development of tools to facilitate nomenclature and management CIRS events, including corrective actions in a more standardized manner

    Implementing human factors in clinical practice

    Get PDF
    OBJECTIVES: To understand whether aviation-derived human factors training is acceptable and useful to healthcare professionals. To understand whether and how healthcare professionals have been able to implement human factors approaches to patient safety in their own area of clinical practice. METHODS: Qualitative, longitudinal study using semi-structured interviews and focus groups, of a multiprofessional group of UK NHS staff (from the emergency department and operating theatres) who have received aviation-derived human factors training. RESULTS: The human factors training was evaluated positively, and thought to be both acceptable and relevant to practice. However, the staff found it harder to implement what they had learned in their own clinical areas, and this was principally attributed to features of the informal organisational cultures. CONCLUSIONS: In order to successfully apply human factors approaches in hospital, careful consideration needs to be given to the local context and informal culture of clinical practice

    A genome-wide linkage analysis of alcoholism on microsatellite and single-nucleotide polymorphism data, using alcohol dependence phenotypes and electroencephalogram measures

    Get PDF
    The Collaborative Study on the Genetics of Alcoholism (COGA) is a large-scale family study designed to identify genes that affect the risk for alcoholism and alcohol-related phenotypes. We performed genome-wide linkage analyses on the COGA data made available to participants in the Genetic Analysis Workshop 14 (GAW 14). The dataset comprised 1,350 participants from 143 families. The samples were analyzed on three technologies: microsatellites spaced at 10 cM, Affymetrix GeneChip(® )Human Mapping 10 K Array (HMA10K) and Illumina SNP-based Linkage III Panel. We used ALDX1 and ALDX2, the COGA definitions of alcohol dependence, as well as electrophysiological measures TTTH1 and ECB21 to detect alcoholism susceptibility loci. Many chromosomal regions were found to be significant for each of the phenotypes at a p-value of 0.05. The most significant region for ALDX1 is on chromosome 7, with a maximum LOD score of 2.25 for Affymetrix SNPs, 1.97 for Illumina SNPs, and 1.72 for microsatellites. The same regions on chromosome 7 (96–106 cM) and 10 (149–176 cM) were found to be significant for both ALDX1 and ALDX2. A region on chromosome 7 (112–153 cM) and a region on chromosome 6 (169–185 cM) were identified as the most significant regions for TTTH1 and ECB21, respectively. We also performed linkage analysis on denser maps of markers by combining the SNPs datasets from Affymetrix and Illumina. Adding the microsatellite data to the combined SNP dataset improved the results only marginally. The results indicated that SNPs outperform microsatellites with the densest marker sets performing the best

    Use of a miniature diamond-anvil cell in a joint X-ray and neutron high-pressure study on copper sulfate pentahydrate

    Get PDF
    Single-crystal X-ray and neutron diffraction data are usually collected using separate samples. This is a disadvantage when the sample is studied at high pressure because it is very difficult to achieve exactly the same pressure in two separate experiments, especially if the neutron data are collected using Laue methods where precise absolute values of the unit-cell dimensions cannot be measured to check how close the pressures are. In this study, diffraction data have been collected under the same conditions on the same sample of copper(II) sulfate pentahydrate, using a conventional laboratory diffractometer and source for the X-ray measurements and the Koala single-crystal Laue diffractometer at the ANSTO facility for the neutron measurements. The sample, of dimensions 0.40 × 0.22 × 0.20 mm(3) and held at a pressure of 0.71 GPa, was contained in a miniature Merrill–Bassett diamond-anvil cell. The highly penetrating diffracted neutron beams passing through the metal body of the miniature cell as well as through the diamonds yielded data suitable for structure refinement, and compensated for the low completeness of the X-ray measurements, which was only 24% on account of the triclinic symmetry of the sample and the shading of reciprocal space by the cell. The two data-sets were combined in a single ‘XN’ structure refinement in which all atoms, including H atoms, were refined with anisotropic displacement parameters. The precision of the structural parameters was improved by a factor of up to 50% in the XN refinement compared with refinements using the X-ray or neutron data separately
    • …
    corecore