The interaction of dark matter cusp with the baryon component in disk galaxies

In this paper we examine the effect of the formation and evolution of the disk galaxy on the distribution of dark halo matter. We have made simulations of isolated dark matter (DM) halo and two component (DM + baryons). N-body technique was used for stellar and DM particles and TVD MUSCL scheme for gas-dynamic simulations. The simulations include the processes of star formation, stellar feedback, heating and cooling of the interstellar medium. The results of numerical experiments with high spatial resolution let us to conclude in two main findings. First, accounting of star formation and supernova feedback resolves the so-called problem of cusp in distribution of dark matter predicted by cosmological simulations. Second, the interaction of dark matter with dynamic substructures of stellar and gaseous galactic disk (e.g., spiral waves, bar) has an impact on the shape of the dark halo. In particular, the in-plane distribution of dark matter is more symmetric in runs, where the baryonic component was taken into account.Comment: 7 pages, 6 figure

The Recent Stellar Archeology of M31 - The Nearest Red Disk Galaxy

We examine the star-forming history (SFH) of the M31 disk during the past few hundred Myr. The luminosity functions (LFs) of main sequence stars at distances R_GC > 21 kpc (i.e. > 4 disk scale lengths) are matched by models that assume a constant star formation rate (SFR). However, at smaller R_GC the LFs suggest that during the past ~10 Myr the SFR was 2 - 3 times higher than during the preceding ~100 Myr. The rings of cool gas that harbor a significant fraction of the current star-forming activity are traced by stars with ages ~100 Myr, indicating that (1) these structures have ages of at least 100 Myr, and (2) stars in these structures do not follow the same relation between age and random velocity as their counterparts throughout the disks of other spiral galaxies, probably due to the inherently narrow orbital angular momentum distribution of the giant molecular clouds in these structures. The distribution of evolved red stars is not azimuthally symmetric, in the sense that their projected density along the north east segment of the major axis is roughly twice that on the opposite side of the galaxy. The north east arm of the major axis thus appears to be a fossil star-forming area that dates to intermediate epochs. Such a structure may be the consequence of interactions with a companion galaxy.Comment: To appear in The Astrophysical Journa

The efficacy of suppressive antibiotic treatment in patients managed non-operatively for periprosthetic joint infection and a draining sinus

Objectives: Patients with prosthetic joint infections (PJIs) not suitable for curative surgery may benefit from suppressive antibiotic therapy (SAT). However, the usefulness of SAT in cases with a draining sinus has never been investigated. Methods: A multicentre, retrospective observational cohort study was performed in which patients with a PJI and a sinus tract were eligible for inclusion if managed conservatively and if sufficient follow-up data were available (i.e. at least 2 years). SAT was defined as a period of > 6 months of oral antibiotic therapy. Results: SAT was initiated in 63 of 72 (87.5 %) included patients. Implant retention during follow-up was the same in patients receiving SAT vs. no SAT (79.4 % vs. 88.9 %; pCombining double low line0.68). In total, 27 % of patients using SAT experienced side effects. In addition, the occurrence of prosthetic loosening in initially fixed implants, the need for surgical debridement, or the occurrence of bacteremia during follow-up could not be fully prevented with the use of SAT, which still occurred in 42 %, 6.3 %, and 3.2 % of cases, respectively. However, the sinus tract tended to close more often (42 % vs. 13 %; pCombining double low line0.14), and a higher resolution of pain was observed (35 % vs. 14 %; pCombining double low line0.22) in patients receiving SAT. Conclusions: SAT is not able to fully prevent complications in patients with a draining sinus. However, it may be beneficial in a subset of patients, particularly in those with pain or the hindrance of a draining sinus. A future prospective study, including a higher number of patients not receiving SAT, is needed

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

How do we perceive activity pacing in rheumatology care? An international delphi survey

Background Activity pacing is a recommended non-pharmacological intervention for the management of rheumatic and musculoskeletal diseases in international clinical guidelines. In clinical practice, activity pacing aims at adapting daily activities, and is often an important component of self-management programs. However, despite its wide endorsement in clinical practice, to date activity pacing is still a poorly understood concept. Objectives To achieve consensus by means of an international Delphi exercise on the most important aspects of activity pacing as an intervention within non-pharmacological rheumatology care. Methods An international, multidisciplinary expert panel comprising 60 clinicians and/or healthcare providers experienced with activity pacing across 12 different countries participated in a Delphi survey. Over four Delphi rounds, the panelists identified and ranked the most important goals of activity pacing, behaviours of activity pacing (the actions people take to meet the goal of activity pacing), strategies to change behaviour in activity pacing (for example goal setting) and contextual factors that should be acknowledged when instructing activity pacing. Besides, topics for future research on activity pacing were formulated and prioritized. Results Of the 60 panelists, nearly two third (63%) completed all four Delphi rounds. The panel prioritized 9 goals, 11 behaviours, 9 strategies to change behaviour and 10 contextual factors of activity pacing. These items were integrated into a consensual list containing the most important aspects of activity pacing interventions in non-pharmacological rheumatology care. Furthermore, the Delphi panel prioritized 9 topics for future research on activity pacing which were included in a research agenda. This agenda highlights that future research should focus on the effectiveness of activity pacing interventions and on appropriate outcome measures to assess its effectiveness, as selected by 64% and 82% of the panelists, respectively. Conclusions The diversity and number of items included in the consensual list developed in the current study reflect the heterogeneity of the concept of activity pacing. This study is an important first step to achieve better transparency and homogeneity within the concept of activity pacing for clinical practice and research

The Effect of Different Type Ia Supernova Progenitors on Galactic Chemical Evolution

Our aim is to show how different hypotheses about Type Ia supernova progenitors can affect Galactic chemical evolution. We include different Type Ia SN progenitor models, identified by their distribution of time delays, in a very detailed chemical evolution model for the Milky Way which follows the evolution of several chemical species. We test the single degenerate and the double degenerate models for supernova Ia progenitors, as well as other more empirical models based on differences in the time delay distributions. We find that assuming the single degenerate or the double degenerate scenario produces negligible differences in the predicted [O/Fe] vs. [Fe/H] relation. On the other hand, assuming a percentage of prompt (exploding in the first 100 Myr) Type Ia supernovae of 50%, or that the maximum Type Ia rate is reached after 3-4 Gyr from the beginning of star formation, as suggested by several authors, produces more noticeable effects on the [O/Fe] trend. However, given the spread still existing in the observational data no model can be firmly excluded on the basis of only the [O/Fe] ratios. On the other hand, when the predictions of the different models are compared with the G-dwarf metallicity distribution, the scenarios with very few prompt Type Ia supernovae can be excluded. Models including the single degenerate or double degenerate scenario with a percentage of 10-13% of prompt Type Ia supernovae produce results in very good agreement with the observations. A fraction of prompt Type Ia supernovae larger than 30% worsens the agreement with observations and the same occurs if no prompt Type Ia supernovae are allowed. In particular, two empirical models for the Type Ia SN progenitors can be excluded: the one without prompt Type Ia supernovae and the one assuming delay time distribution going like t^{-0.5}.Comment: Accepted by A&

Science Frontiers In Galaxy Evolution: Deep-Wide Surveys

Astro2010: The Astronomy and Astrophysics Decadal Survey : Science White Papers no 79. Available online : http://www8.nationalacademies.org/astro2010/DetailFileDisplay.aspx?id=24

The Age-Metallicity Relation in the Thin Disk of the Galaxy

HST trigonometric distances, photometric metallicities, isochronic ages from the second revised version of the Geneva--Copenhagen survey, and uniform spectroscopic Fe and Mg abundances from our master catalog are used to construct and analyze the age--metallicity and age-relative Mg abundance relations for stars of the thin disk. The influences of selection effects are discussed in detail. It is demonstrated that the radial migration of stars does not lead to appreciable distortions in the age dependence of the metallicity. During the first several billion years of the formation of the thin disk, the interstellar material in this disk was, on average, fairly rich in heavy elements ( ~-0.2) and poorly mixed. However, the metallicity dispersion continuously decreased with age, from \sigma_{[Fe/H]}~0.22 to ~0.13. All this time, the mean relative abundance of Mg was somewhat higher than the solar value (~0.1). Roughly four to five billion years ago, the mean metallicity began to systematically increase, while retaining the same dispersion; the mean relative Mg abundance began to decrease immediately following this. The number of stars in this subsystem increased sharply at the same time. These properties suggest that the star-formation rate was low in the initial stage of formation of the thin disk, but abruptly increased about four to five billion years ago.Comment: 16 page, 7 figures, accepted 2011, Astron. Rep., v.55, No.8, p.667-68

Drug suicide: a sex-equal cause of death in 16 European countries

Background: There is a lack of international research on suicide by drug overdose as a preventable suicide method. Sex- and age-specific rates of suicide by drug self-poisoning (ICD-10, X60-64) and the distribution of drug types used in 16 European countries were studied, and compared with other self-poisoning methods (X65-69) and intentional self-injury (X70-84).Methods: Data for 2000-04/05 were collected from national statistical offices. Age-adjusted suicide rates, and age and sex distributions, were calculated.Results: No pronounced sex differences in drug self-poisoning rates were found, either in the aggregate data (males 1.6 and females 1.5 per 100,000) or within individual countries. Among the 16 countries, the range (from some 0.3 in Portugal to 5.0 in Finland) was wide. 'Other and unspecified drugs' (X64) were recorded most frequently, with a range of 0.2-1.9, and accounted for more than 70% of deaths by drug overdose in France, Luxembourg, Portugal and Spain. Psychotropic drugs (X61) ranked second. The X63 category ('other drugs acting on the autonomic nervous system') was least frequently used. Finland showed low X64 and high X61 figures, Scotland had high levels of X62 ('narcotics and hallucinogens, not elsewhere classified') for both sexes, while England exceeded other countries in category X60. Risk was highest among the middle-aged everywhere except in Switzerland, where the elderly were most at risk.Conclusions: Suicide by drug overdose is preventable. Intentional self-poisoning with drugs kills as many males as females. The considerable differences in patterns of self-poisoning found in the various European countries are relevant to national efforts to improve diagnostics of suicide and appropriate specific prevention. The fact that vast majority of drug-overdose suicides came under the category X64 refers to the need of more detailed ICD coding system for overdose suicides is needed to permit better design of suicide-prevention strategies at national level