181 research outputs found
Ring Formation from an Oscillating Black Hole
Massive black hole (BH) mergers can result in the merger remnant receiving a
"kick", of order 200 km s or more, which will cause the remnant to
oscillate about the galaxy centre. Here we analyze the case where the BH
oscillates through the galaxy centre perpendicular or parallel to the plane of
the galaxy for a model galaxy consisting of an exponential disk, a Plummer
model bulge, and an isothermal dark matter halo. For the perpendicular motion
we find that there is a strong resonant forcing of the disk radial motion near
but somewhat less than the "resonant radii" where the BH oscillation
frequency is equal one-half, one-fourth, (1/6, etc.) of the radial epicyclic
frequency in the plane of the disk. Near the resonant radii there can be a
strong enhancement of the radial flow and disk density which can lead to shock
formation. In turn the shock may trigger the formation of a ring of stars near
. As an example, for a BH mass of and a kick velocity of
150 km s, we find that the resonant radii lie between 0.2 and 1 kpc. For
BH motion parallel to the plane of the galaxy we find that the BH leaves behind
it a supersonic wake where star formation may be triggered. The shape of the
wake is calculated as well as the slow-down time of the BH.
The differential rotation of the disk stretches the wake into ring-like
segments.Comment: 7 pages, 7 figure
Melatonin prevents chemical-induced Haemopoietic cell death
Melatonin (MEL), a methoxyindole synthesized by the pineal gland, is a powerful antioxidant in tissues as well as within cells, with a fundamental role in ameliorating homeostasis in a number of specific pathologies. It acts both as a direct radical scavenger and by stimulating production/activity of intracellular antioxidant enzymes. In this work, some chemical triggers, with different mechanisms of action, have been chosen to induce cell death in U937 hematopoietic cell line. Cells were pre-treated with 100 μM MEL and then exposed to hydrogen peroxide or staurosporine. Morphological analyses, TUNEL reaction and Orange/PI double staining have been used to recognize ultrastructural apoptotic patterns and to evaluate DNA behavior. Chemical damage and potential MEL anti-apoptotic effects were quantified by means of Tali® Image-Based Cytometer, able to monitor cell viability and apoptotic events. After trigger exposure, chromatin condensation, micronuclei formation and DNA fragmentation have been observed, all suggesting apoptotic cell death. These events underwent a statistically significant decrease in samples pre-treated with MEL. After caspase inhibition and subsequent assessment of cell viability, we demonstrated that apoptosis occurs, at least in part, through the mitochondrial pathway and that MEL interacts at this level to rescue U937 cells from death. © 2014 by the authors; licensee MDPI, Basel, Switzerland
Bond strength of self-adhesive flowable composites and glass ionomer cements to primary teeth: A systematic review and meta-analysis of in vitro studies
Background: Conventional composites are largely used in pediatric restorative dentistry and demonstrate successful clinical outcomes. However, the need for simplification of operative steps in young or uncooperative children demands reliable alternatives. Therefore, the aim of the present systematic review and meta-analysis was to evaluate the in vitro bond strength of glass ionomer cements (GICs) and self-adhesive flowable composites (SFCs) on deciduous teeth. Methods: A comprehensive literature search according to the PRISMA checklist was manually and electronically performed by two independent reviewers through the following databases: MEDLINE/PubMed, Google Scholar, Scopus, and Embase, to include in vitro studies comparing GICs and SFCs bond strength values of restorations on primary teeth. In addition, three groups of meta-analyses were conducted using random-effects models. Results: Three articles meeting the inclusion criteria were selected and subjected to both qualitative and quantitative assessment. No statistically significant difference was found between SFC versus GIC; however, both groups significantly differed with conventional flowable composites (CFs). Conclusions: Despite the absence of significant difference in bond strength values, SFCs may be considered a valid alternative to GICs in the restoration of deciduous teeth, although CFs proved better in vitro performances
Modelling Future Mobility - Scenario Simulation at Macro Level
The aim of the report is to simulate policy scenarios for passenger transport using Europe-wide transport models, estimate their potential impacts and demonstrate how do they differ from each other and from the reference scenario for 2030. In more detail, the main objectives of the deliverable can be given as follows:
- to model future multi-modal mobility scenarios for passengers formulated within the previous tasks of the project,
- to simulate impacts of identified trends and selected strategies on demand, supply and technology at macro level,
- to analyse impacts of selected policies and identified trends on mobility patterns such as in travel demand and modal split,
- to estimate potential impacts of selected policy measures on environmental indicators via transport emissions and vehicle fleet sizes,
- to compare impacts of different scenario options in quantitative terms and provide useful insights for exploring best policy scenarios and strategies for sustainable passenger transport.
The research has been conducted under the OPTIMISM project which was received funding from the European Union's Seventh Framework Programme (FP7/2007-2013), grant agreement n° 284892. The report has been produced as the OPTIMISM project deliverable 3.4: Modelling Future Mobility - Scenario Simulation at Macro Level.JRC.J.1-Economics of Climate Change, Energy and Transpor
Constraints on cross-section and lifetime of dark matter with HAWC Observations of dwarf Irregular galaxies
It has been shown that the dynamics of dwarf Irregular (dIrr) galaxies are dominated by dark matter. It is also observed that these galaxies have low star formation rates and metallicities, and no gamma-ray emission at ultra very high energies is expected. Because of their distance, dark matter content and vast number, dIrr galaxies are good targets to perform indirect dark matter searches by ground-based and wide field of view gamma-ray experiments, like HAWC. We analyzed data at the position of 31 dIrr galaxies within the HAWC field-of-view and no significant excess was found. Here, we present the individual and combined limits on the annihilation cross-section and decay lifetime of weakly interacting massive particles with mass between 1 and 100 TeV
From shunt to recovery: A multidisciplinary approach to hydrocephalus treatment in severe acquired brain injury rehabilitation
Background: Hydrocephalus among Severe Acquired Brain Injury (SABI) patients remains overlooked during rehabilitation. Methods: A retrospective cohort study was carried out of traumatic and non-traumatic SABI patients with hydrocephalus, consecutively admitted over 9 years in a tertiary referral specialized rehabilitation hospital. Patients were treated with ventriculoperitoneal shunt before or during inpatient rehabilitation and assessed using the Level of Cognitive Functioning Scale and Disability Rating Scale. Logistic regression models were used to identify predictors of post-surgical complications. Linear regression models were used to investigate predictors of hospital length of stay (LOS), disability, and cognitive function. Results: Of the 82 patients, 15 had post-surgical complications and 16 underwent cranioplasty. Shunt placement complication risk was higher when fixed vs. when programmable pressure valves were used. A total of 56.3% achieved functional improvement at discharge and 88.7% improved in cognitive function; of the 82 patients, 56% were discharged home. In multiple regression analyses, higher disability at discharge was related to cranioplasty and longer LOS, while poorer cognitive function was associated with cranioplasty. Increase in LOS was associated with increasing time to shunt and decreasing age. Conclusions: A significant improvement in cognitive and functional outcomes can be achieved. Cranioplasty increased LOS, and fixed pressure valves were related to poorer outcomes
Searching for TeV DM evidence from Dwarf Irregular Galaxies with the HAWC Observatory
The dynamics of dwarf irregular (dIrr) galaxies are observed to be dominated by dark matter (DM). Recently, the DM density distribution has been studied for 31 dIrrs. Their extended DM halo (Burket type profile) makes these objects good candidates for DM searches. Located in Puebla (Mexico), the High Altitude Water Cherenkov (HAWC) Observatory is an optimal instrument to perform such DM searches, because of its large sky coverage (8.4 sr per day). We analyzed a set of two years of HAWC data and we found no significant DM signal from dIrr galaxies. We present the upper limits for DM annihilation cross-section with dIrr galaxies
Three-dimensional virtual anatomy as a new approach for medical student’s learning
Most medical and health science schools adopt innovative tools to implement the teaching of anatomy to their undergraduate students. The increase in technological resources for educational purposes allows the use of virtual systems in the field of medicine, which can be considered decisive for improving anatomical knowledge, a requisite for safe and competent medical practice. Among these virtual tools, the Anatomage Table 7.0 represents, to date, a pivotal anatomical device for student education and training medical professionals. This review focuses attention on the potential of the Anatomage Table in the anatomical learning process and clinical practice by discussing these topics based on recent publication findings and describing their trends during the COVID-19 pandemic period. The reports documented a great interest in and a positive impact of the use of this technological table by medical students for teaching gross anatomy. Anatomage allows to describe, with accuracy and at high resolution, organ structure, vascularization, and innervation, as well as enables to familiarize with radiological images of real patients by improving knowledge in the radiological and surgical fields. Furthermore, its use can be considered strategic in a pandemic period, since it ensures, through an online platform, the continuation of anatomical and surgical training on dissecting cadavers
Gravitomagnetic corrections to the lensing deflection angle for spiral galaxy models
We investigate the effects of the gravitomagnetic corrections to the usual
gravitational lens quantities for a specific lensing mass distribution modelled
after spiral galaxies. An exponential disk is embedded into two different
spherical halo models where disk and haloes parameters are fixed according to
the observed mass to light ratios, galaxy magnitudes and rotation curves. The
general expressions for the lensing deflection angle are given also taking into
account the orientation of the galaxy disk plane with respect to the lens
plane. It is found that the gravitomagnetic term changes the deflection angle
by a typical amount of the order of ten microarcseconds.Comment: 7 pages, 2 figures, accepted for publication on MNRA
Modeling the Mass Distribution in the Spiral Galaxy NGC 3198
We study the HI Rotation Curve of the spiral galaxy NGC 3198 in terms of mass decomposition. We model the Rotation Curve in the framework of different models for the Dark Matter distribution: the Burkert profile and NFW profile. We show that Universal Rotation Curve (Burkert halo+stellar disk+gas disk) fits data accurately. Instead, the NFW (NFW halo+stellar disk+gas disk) model gives non-physical values of NFW halo parameters. \ua9 Published under licence by IOP Publishing Ltd
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