On the alpha formalism for the common envelope interaction

The {\alpha}-formalism is a common way to parametrize the common envelope interaction between a giant star and a more compact companion. The {\alpha} parameter describes the fraction of orbital energy released by the companion that is available to eject the giant star's envelope. By using new, detailed stellar evolutionary calculations we derive a user-friendly prescription for the {\lambda} parameter and an improved approximation for the envelope binding energy, thus revising the {\alpha} equation. We then determine {\alpha} both from simulations and observations in a self consistent manner. By using our own stellar structure models as well as population considerations to reconstruct the primary's parameters at the time of the common envelope interaction, we gain a deeper understanding of the uncertainties. We find that systems with very low values of q (the ratio of the companion's mass to the mass of the primary at the time of the common envelope interaction) have higher values of {\alpha}. A fit to the data suggests that lower mass companions are left at comparable or larger orbital separations to more massive companions. We conjecture that lower mass companions take longer than a stellar dynamical time to spiral in to the giant's core, and that this is key to allowing the giant to use its own thermal energy to help unbind its envelope. As a result, although systems with light companions might not have enough orbital energy to unbind the common envelope, they might stimulate a stellar reaction that results in the common envelope ejection.Comment: 17 pages, 8 figures. Accepted by MNRA

Star formation in young star cluster NGC 1893

We present a comprehensive multi-wavelength study of the star-forming region NGC 1893 to explore the effects of massive stars on low-mass star formation. Using near-infrared colours, slitless spectroscopy and narrow-band $H\alpha$ photometry in the cluster region we have identified candidate young stellar objects (YSOs) distributed in a pattern from the cluster to one of the nearby nebulae Sim 129. The $V, (V-I)$ colour-magnitude diagram of the YSOs indicates that majority of these objects have ages between 1 to 5 Myr. The spread in the ages of the YSOs may indicate a non-coeval star formation in the cluster. The slope of the KLF for the cluster is estimated to be $0.34\pm0.07$, which agrees well with the average value ($\sim 0.4$) reported for young clusters. For the entire observed mass range $0.6 < M/M_\odot \le 17.7$ the value of the slope of the initial mass function, $`\Gamma$', comes out to be $-1.27\pm0.08$, which is in agreement with the Salpeter value of -1.35 in the solar neighborhood. However, the value of $`\Gamma$' for PMS phase stars (mass range $0.6 < M/M_\odot \le 2.0$) is found to be $-0.88\pm0.09$ which is shallower than the value ($-1.71\pm0.20$) obtained for MS stars having mass range $2.5 < M/M_\odot \le 17.7$ indicating a break in the slope of the mass function at $\sim 2 M_\odot$. Estimated $`\Gamma$' values indicate an effect of mass segregation for main-sequence stars, in the sense that massive stars are preferentially located towards the cluster center. The estimated dynamical evolution time is found to be greater than the age of the cluster, therefore the observed mass segregation in the cluster may be the imprint of the star formation process. There is evidence for triggered star formation in the region, which seems to govern initial morphology of the cluster.Comment: Accepted for the publication in MNRAS, 21 pages, 26 figures, 10 table

Reframing QoL assessment in persons with neurodevelopmental disorders

AbstractThe paper reviews the international literature on quality of life (QoL) for persons withneurodevelopmental disorders (NDD) in order to define the theoretical frame for optimalassessment. The application of the QoL approach to assessment procedures shouldbe based on three main aspects: shared QoL, personal QoL and family QoL. The first aspectrefers to characteristics of individual life that are shared with other people. The secondaspect proceeds from the fact that each individual has a changing set of personal attributesthat determine the subjective experience of life. In the third aspect the previoustwo are applied to the family that includes a person with NDD. Disability impacts thewhole family and the determination of appropriate conceptualization of family outcomesrequires an understanding of the impact of members with a disability on family QoL. Atany level, it seems best to take a comprehensive approach to assessing QoL, integratingsubjective and objective aspects, self-reports and hetero-evaluations. The QoL approachis above all a way to explore the rich intricacies of personal quality of life. Such assessmentmay be used effectively with people with NDD, independently from the severityof their functioning impairment. Individuals with profound ID may express their innerstates through consistent behavioural repertoires, which can be discerned by personsclosest to them and validated by more independent others. Attention must be paid in usingnon-generic instruments, such as those that measure health-related QoL. Althoughthey do focus on the individual person, they still support a theoretical perspective ofQoL that has not departed significantly from the traditional medical approach. Currentlyavailable generic tools, although they have some common conceptual and evaluationcharacteristics, still show considerable differences in the areas to be included in “sharedQoL”, the dimensions used to evaluate “Individual QoL”, and the role attributed toindicators of QoL. QoL assessment should not represent a classification of individuals,services or systems, but it should help provide, within service systems and organizations,a value system that is consistent with those values held by people with NDD

Atomic and electronic structure of the cleaved non-polar 6H-SiC(11-20) and GaN(1-100) surfaces

Der Titel dieser Doktorarbeit lautet Atomic and electronic structure of the cleaved non-polar 6H-SiC(11-20) and GaN(1-100) surfaces (Atomare und elektronische Struktur der gespaltenen nicht-polaren 6H-SiC(11-20) und GaN(1-100) Oberflächen). Sie enthält die Ergebnisse von einer kombinierten experimentellen und theoretischen Studie die im Rahmen einer Kooperation zwischen dem IV. Physikalischen Institut der Georg-August Universität Göttingen (Deutschland) und dem Physikalischen Institut der Universität Modena und Reggio Emilia und dem National Research Center (CNR) in Parma (Italien) durchgeführt wurde. Das Ziel dieser Studie war es, die physikalischen Eigenschaften der gespaltenen nicht-polaren Silizium-Carbid (6H-SiC) und Gallium-Nitrid (GaN) Halbleiter Oberflächen, die ein hohes Potential für Leucht- und Laserdioden hoher Effizienz im grünen Bereich besitzen, zu verstehen. Das Ziel ist es die so genannte grüne Bandlücke von Nitrid-Leuchtdioden zu schließen. Wegen den vielversprechenden industriellen Anwendungen und dem Fehlen von experimentellen Messungen auf den sauberen nicht-polaren 6H-SiC und GaN Oberflächen haben wir beschlossen diese Oberflächen mittels Querschnitts-Rastertunnelmikroskopie und -spektroskopie (X-STM/STS) zu untersuchen. Die Doktorarbeit enthält die ersten publizierten experimentellen Daten auf den gespaltenen nicht-polaren 6H-SiC(11-20) und GaN(1-100) Oberflächen. Die Ergebnisse über das SiC System wurden im Physical Review B publiziert (75, 165312, 2007) und die Ergebnisse über das GaN System wurden bei der gleichen Zeitschrift für die Veröffentlichung akzeptiert (2009)

Intermediate mass stars: updated models

A new set of stellar models in the mass range 1.2 to 9 $M_{\odot}$ is presented. The adopted chemical compositions cover the typical galactic values, namely $0.0001 \le Z \le 0.02$ and $0.23 \le Y \le 0.28$. A comparison among the most recent compilations of similar stellar models is also discussed. The main conclusion is that the differencies among the various evolutionary results are still rather large. For example, we found that the H-burning evolutionary time may differ up to 20 %. An even larger disagreement is found for the He-burning phase (up to 40-50 %). Since the connection between the various input physics and the numerical algorithms could amplify or counterbalance the effect of a single ingredient on the resulting stellar model, the origin of this discrepancies is not evident. However most of these discrepancies, which are clearly found in the evolutionary tracks, are reduced on the isochrones. By means of our updated models we show that the ages inferred by the theory of stellar evolution is in excellent agreement with those obtained by using other independent methods applied to the nearby Open Clusters. Finally, the theoretical initial/final mass relation is revised.Comment: 35 pages, 24 figures, 4 tables, accepted for publication in the Astrophisycal Journa

Stellar physical parameters from Str ömgren photometry. Application to the young stars in the Galactic anticenter survey

M. Monguió, F. Figueras, and P. Grosbøl, “Stellar physical parameters from Strömgren photometry. Application to the young stars in the Galactic anticenter survey”, Astronomy & Astrophysics, Vol. 568, September 2014. Thhis version of record is available online at: https://doi.org/10.1051/0004-6361/201423703 Reproduced with Permission from Astronomy and Astrophysics, © ESO 2016.Aims. The aim is to derive accurate stellar distances and extinctions for young stars of our survey in the Galactic anticenter direction using the Str\"omgren photometric system. This will allow a detailed mapping of the stellar density and absorption toward the Perseus arm. Methods. We developed a new method for deriving physical parameters from Str\"omgren photometry and also implemented and tested it. This is a model-based method that uses the most recent available stellar atmospheric models and evolutionary tracks to interpolate in a 3D grid of the unreddened indexes [m1], [c1] and Hbeta. Distances derived from both this method and the classical pre-Hipparcos calibrations were tested against Hipparcos parallaxes and found to be accurate. Results. Systematic trends in stellar photometric distances derived from empirical calibrations were detected and quantified. Furthermore, a shift in the atmospheric grids in the range Teff=[7000,9000]K was detected and a correction is proposed. The two methods were used to compute distances and reddening for about 12000 OBA-type stars in our Str\"omgren anticenter survey. Data from the IPHAS and 2MASS catalogs were used to complement the detection of emission line stars and to break the degeneracy between early and late photometric regions. We note that photometric distances can differ by more than 20%, those derived from the empirical calibrations being smaller than those derived with the new method, which agree better with the Hipparcos data.Peer reviewe

Ethical prescribing of psychotropic medications for people with neurodevelopmental disorders

Objectives People with neurodevelopmental disorders (NDDs) such as intellectual and developmental disabilities (IDD) and autism are subjected to restrictive practices like physical restraint and the overuse of psychotropic medications for challenging behaviour in the absence of a psychiatric disorder. This practice may lead to human rights violations. Rational and evidence-based shared decision-making for person-centred planning will help reduce this practice. Methods We have discussed in this paper the issue of the overmedication of people with NDD, explaining how this practice may violate the United Nations (UN) Convention on the Rights of Persons with Disabilities (CRPD). Results We have discussed how the following UN CRPD Articles may be affected by overmedication, including Article 15 (degrading treatment or punishment), 16 (abuse), 17 (the integrity of the person), and 25 (health). The other Articles that may be indirectly affected by this practice are 5 (equality and non-discrimination), 9 (accessibility), 19 (independent living and community inclusion), 21 (access to information), 24 (education), 26 (rehabilitation), 27 (work and employment), 28 (adequate living standard), and 30 (participation in recreation and leisure). Conclusions Overmedication of people with NDD, particularly the off-licence use of psychotropics for challenging behaviour, the side effects of these medications impacting the person’s quality of life are likely to violet several UN Articles on Rights of Persons with Disabilities. Following the right guidelines may help reduce these human rights violations

The Person-Centered Health model in Intellectual Developmental Disorders/Intellectual Disability

Background and Objectives: This paper analyses the different aspects related to the conceptualization and assessment of Intellectual Developmental Disorders / Intellectual Disability (IDD/ID) following the Person-centered Integrative Diagnostic (PID) model of the International Network for Person-centered Medicine, with a main emphasis on the health status and health self-perception. Methods: Conceptual paper, including expert opinions based on literature review. Results: The conceptualization of IDD/ID should shift the traditional over-reliance on the intelligence (IQ) score in favour of the daily life expression of specific cognitive functions and the determination of the levels of severity of intellectual functioning, that is currently based on the person's IQ score, should be reached through a system that is predicated on the person's satisfaction attainment towards life. The assessment of cognition should be aimed at identifying those dysfunctions that have the highest impact on individual behaviour, skills, adaptation, autonomy, and quality of life across the life span, highlighting personal cognitive strengths and weaknesses that can be worthwhile for the planning of effective interventions. Conclusions: Authors conclude that the application of the PID model to IDD/ID represents a prototypical example of how this approach can be useful for understanding complex constructs in health care. An overview of the main factors related to the implementation of the person-centered care model by health systems and services is also provided

An experimental approach to the cleaning of a polymateric textile weave: set-up of the alternative methodology and instrumentation

Aim of the present research is the setup of an alternative methodology and instrumentation to be applied for cleaning ancient tapestries which need restoration. A new instrument based on the simultaneous dispensing and aspiration of water (hydro-aspiration method) and capable of removing the deposited particulate matter (DPM), has been developed and its performances tested on an ancient polymateric tapestry belonging a precious series called “Ulysses Stories”, stored at the Quirinale Palace (Rome). This innovative system has been compared to traditional methodologies commonly employed by restores for tapestries cleaning operations. At this purpose, the quantity and the chemical composition of the particulate matter removed by the different systems and collected on quartz fibre filters, have been estimated. Different analytical techniques have been applied to this purpose. The hydro-aspiration method resulted to be more efficient in removing the dirt and also in preserving the structure of these precious metallic yarns