165 research outputs found
A finer view of the conditional galaxy luminosity function and magnitude-gap statistics
The gap between first and second ranked galaxy magnitudes in groups is often
considered a tracer of their merger histories, which in turn may affect galaxy
properties, and also serves to test galaxy luminosity functions (LFs). We
remeasure the conditional luminosity function (CLF) of the Main Galaxy Sample
of the SDSS in an appropriately cleaned subsample of groups from the Yang
catalog. We find that, at low group masses, our best-fit CLF have steeper
satellite high ends, yet higher ratios of characteristic satellite to central
luminosities in comparison with the CLF of Yang et al. (2008). The observed
fractions of groups with large and small magnitude gaps as well as the Tremaine
& Richstone (1977) statistics, are not compatible with either a single
Schechter LF or with a Schechter-like satellite plus lognormal central LF.
These gap statistics, which naturally depend on the size of the subsamples, and
also on the maximum projected radius, , for defining the 2nd
brightest galaxy, can only be reproduced with two-component CLFs if we allow
small gap groups to preferentially have two central galaxies, as expected when
groups merge. Finally, we find that the trend of higher gap for higher group
velocity dispersion, , at given richness, discovered by Hearin
et al. (2013), is strongly reduced when we consider in bins of
richness, and virtually disappears when we use group mass instead of
. This limits the applicability of gaps in refining
cosmographic studies based on cluster counts.Comment: 18 pages, 13 figures, 5 tables, submitted to MNRAS, comments are
welcom
Group galaxy number density profiles far out: is the 'one-halo' term NFW out to virial radii?
While the density profiles (DPs) of CDM haloes obey the NFW law out
to roughly one virial radius, , the structure of their outer parts
is still poorly understood, since the 1-halo term describing the halo itself is
dominated by the 2-halo term representing the other haloes picked up. Using a
semi-analytical model, we measure the real-space `1-halo' number DP of groups
out to by assigning each galaxy to its nearest group with
mass above , in units of the group . If is
small (large), the outer DP of groups falls rapidly (slowly). We find that
there is an optimal for which the stacked DP resembles the NFW
model to dex accuracy out to . We find similar
long-range NFW surface DPs (out to ) in the SDSS
observations using a galaxy assignment scheme that combines the non-linear
virialized regions of groups with their linear outer parts. The optimal scales as the minimum mass of the groups that are stacked to the power
. Our results suggest that the NFW model does not solely originate
from violent relaxation. Moreover, populating haloes with galaxies using HOD
models must proceed out to larger radii than usually done.Comment: 5 pages, 4 figures. Accepted for publication in MNRAS Letters. Final
version including discussion on the backsplash radiu
Constraints on feedback processes during the formation of early-type galaxies
Galaxies are found to obey scaling relations between a number of observables.
These relations follow different trends at the low- and the high-mass ends. The
processes driving the curvature of scaling relations remain uncertain. In this
letter, we focus on the specific family of early-type galaxies, deriving the
star formation histories of a complete sample of visually classified galaxies
from SDSS-DR7 over the redshift range 0.01<z<0.025, covering a stellar mass
interval from 10^9 to 3 x 10^11 Msun. Our sample features the characteristic
"knee" in the surface brightness vs. mass distribution at Mstar~3 x 10^10 Msun.
We find a clear difference between the age and metallicity distributions of the
stellar populations above and beyond this knee, which suggests a sudden
transition from a constant, highly efficient mode of star formation in
high-mass galaxies, gradually decreasing towards the low-mass end of the
sample. At fixed mass, our early-type sample is more efficient in building up
the stellar content at early times in comparison to the general population of
galaxies, with half of the stars already in place by redshift z~2 for all
masses. The metallicity-age trend in low-mass galaxies is not compatible with
infall of metal-poor gas, suggesting instead an outflow-driven relation.Comment: 12 pages,3 figures, accepted for publication in ApJ
Planetary nebulae and the ionization of the interstellar medium in galaxies
We discuss the role of planetary nebulae and their progeny in galaxy context in terms of ionization of the galaxy interstellar medium. This regards ionized gas outside the disk of spiral galaxies, the diffuse ionized medium in spiral galaxies, and the weak line emission of elliptical galaxies
Abundances from integrated spectra of 47 Tucanae (NGC 104)
47 Tucanae is among the most studied and observed globular clusters, given its proximity. The aim of this work is to study in detail the integrated spectrum of 47 Tucanae, as a template, in order to have a list of reliable lines that are validated for a moderate spectral resolution case. The spectrum of 47 Tucanae is reproduced by computing synthetic spectra, taking into account individual element abundances. The results are compared with other methods. We reproduce the integrated spectrum in the range 4500–9000 Å and derive abundances from individual lines of Na, Mg, Al, Si, Ca, Ti, Ba, and Eu. We report a list of lines that are suitable for abundance derivation. Adopting these abundances, we are able to fit the well-known triplets of Mg I and Ca II. Finally, the effect of multiple stellar populations through enhanced Na abundances are tested. Element abundances derived are compatible with previous literature abundances, from different methods. The method applied here to build integrated synthetic spectra can be used to derive abundances from observed integrated spectra of distant and faint clusters, that are usually observed at low or moderate spectral resolution
FEROS Abundance Analysis of 21 Bulgelike SMR Stars
We analyze a sample of 21 super-metal-rich (SMR) stars, using high-resolution échelle spectra obtained with the Fiber-fed Extended Range Optical Spectrograph at the 1.5m ESO telescope. The metallicities are in the range 0.07 ≤ [Fe/H] ≤ 0.45, 3 of them in common with Pompéia et al. (2009). Geneva photometry, astrometric data from Hipparcos, and radial velocities from CORAVEL are available for these stars. The peculiar kinematics suggests the thin disk close to the bulge as the probable birthplace of these stars (Grenon 1999). From Hipparcos data, it appears that the turnoff of this population indicates an age of 10-11 Gyr (Grenon 1999). Detailed analysis of the sample stars is carried out, and atmospheric parameters are derived from spectroscopic and photometric determinations. Oxygen abundances of these stars are derived, and [O/Fe] overabundances up to +0.35 are foun
Follow up de enfermagem ao paciente pós-transplante de células-tronco hematopoiéticas autogênico
Dissertação (mestrado profissional) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Gestão do Cuidado em Enfermagem, Florianópolis, 2016.O presente estudo teve como objetivo geral: construir e aplicar follow-up de enfermagem via telefone pós-alta hospitalar do paciente submetido ao transplante de células-tronco hematopoiéticas autogênico no Centro de Pesquisas Oncológicas, uma instituição oncológica do Estado de Santa Catarina, Brasil e, como objetivos específicos: identificar se as orientações para alta pós-transplante atendem às necessidades vivenciadas pelos pacientes e familiares; identificar as dificuldades e facilidades encontradas pelos pacientes submetidos ao transplante durante a prática de cuidados domiciliares; identificar as alterações de saúde vivenciadas no domicílio e relatadas pelos pacientes submetidos ao transplante pós-alta hospitalar. A escolha para implantação do follow-up seguiu as recomendações do Ministério da Saúde, pois esta estratégia permite o desenvolvimento de cuidado proativo. O referencial teórico escolhido para sustentação teórica foi a Teoria do Autocuidado, proposta por Dorothea Orem, que orienta a sistematização da assistência de enfermagem no cenário do estudo. Para tanto, foi realizado estudo descritivo. Para o desenvolvimento do estudo, primeiramente, foi elaborada a proposta de follow-up de enfermagem, que constituiu-se de um questionário, contendo perguntas abertas e fechadas, com aplicabilidade via ligação telefônica. A proposta foi validada pela equipe multiprofissional e cinco pacientes. Os participantes do estudo foram nove pacientes submetidos ao transplante de células-tronco hematopoiéticas, entre agosto e setembro de 2015. Para a coleta de dados, realizada entre agosto e outubro de 2015 aplicou-se o follow-up de enfermagem via ligação telefônica, realizada entre 16º e 24º dia após a alta hospitalar. Para análise, os dados coletados foram agrupados por similaridade e submetidos à medida de frequência, sendo que as perguntas abertas foram transcritas antes do agrupamento das informações, na sequência os resultados foram discutidos a partir do referencial teórico e estudos relacionados aos resultados encontrados. A12pesquisa foi realizada seguindo-se os termos legais para pesquisa com ser humano. Por meio deste estudo foi possível construir um produto para o cuidado de enfermagem e identificou-se as necessidades dos pacientes vivenciadas no domicílio, o que possibilitou a orientação de cuidados específicos para sanar ou reduzir as demandas de necessidades e/ou indicar encaminhamentos necessários aos pacientes e familiares no domicílio. As alterações de saúde predominantes encontradas na aplicação do follow-up foram astenia, náusea, alteração do paladar, dor e alterações psicossociais. Os participantes apontaram que as orientações para alta atendem, em geral, as necessidades vivenciadas pelos pacientes e familiares. Relataram dúvidas quanto ao uso de máscaras descartáveis, animais de estimação, receio quanto à necessidade de realização de um segundo transplante; limpeza dos talheres e roupas e os cuidados diante das alterações de saúde. Quanto às facilidades destacaram o manual educativo fornecido pelo cenário do estudo e o atendimento prestado pela equipe multiprofissional. Com a aplicação do follow-up buscou-se a redução dos riscos pós-transplante de células-tronco hematopoiéticas autogênico, a melhoria da qualidade dos cuidados de enfermagem e da equipe multiprofissional, proporcionando maior segurança e conforto ao paciente transplantado pós-alta hospitalar. Os resultados apontaram que o follow-up de enfermagem via telefone é uma tecnologia viável e acessível, que possibilita o esclarecimento de dúvidas, orienta o cuidado domiciliar pós-alta, dá suporte ao enfrentamento da nova condição de saúde, sem necessidade de deslocamento do paciente, como também, auxilia no controle das complicações e reduz os custos para o sistema de saúde. Além disto, o follow-up de enfermagem foi reconhecido pelos pacientes como uma boa prática de cuidados que deve ser mantida pós-alta do transplante.Abstract : The overall objective of this study was: to build and apply a nursing follow up via telephone after discharge from the hospital of patients who have had autogenic hematopoietic stem cell?s transplant in the Oncology Research Centre, an oncology institution of Santa Catarina State, Brazil. As specific objectives: to identify if orientations after transplant discharge meet the needs experienced by patients and their families; to identify difficulties and facilities found by transplanted patients during home care practices; to identify health modification experienced at home and reported by transplanted patients after discharge from the hospital. The follow up implementation?s choice has followed the recommendations of the Ministry of Health, once this strategy allows a proactive care development. The theoretical background chosen was the Self-care Theory, by Dorothea Orem, which leads the nursing assistance systematization in this descriptive study. To develop the study, at first it was drafted the proposed nursing follow up, which consisted of a questionnaire with open and closed questions, with applicability via phone call. The multidisciplinary team and five patients validated the proposal. The study participants were nine patients undergoing transplantation of hematopoietic stem cells, between August and September 2015. To data collection, conducted between August and October 2015 was applied to the nursing follow up via telephone call held between 16 and 24 days after hospital discharge. For analysis, data were grouped by similarity and submitted as its frequency, and the open-ended questions were transcribed before the grouping of information and then results were discussed from theoretical background and from studies related to it. Research was performed following the legal terms for human beings' research. Through this study it was possible to build a product for nursing care and to identify the patients' needs at home, allowing the guidance of specific care to remedy or reduce the needs' demands and/or indicate necessary referrals14to patients and their families at home. The predominant health changes observed in follow up application were asthenia, nausea, taste disturbance, pain and psychosocial changes. Participants pointed out that the guidelines for hospital discharge meet the needs experienced by patients and families. They have reported doubts about the use of disposable masks, pets, fear about the need to perform a second transplant; cleaning utensils and clothes and care on the health changes. As for the facilities it was highlighted the educational manual provided by the study and the care provided by the multidisciplinary team. With the follow-up implementation it has been sought the autogenic hematopoietic stem cell?s post-transplant risks reduction, improving the quality of nursing care and of the multidisciplinary team, providing greater safety and comfort to the post-discharge transplant patients. Results have indicated that the nursing follow up via telephone is a viable and affordable technology that enables answering questions, orients the post-discharge home care, supports to face a new health condition without the need for patient displacement, but also assists in controlling complications and reduces costs to the health system. Moreover, the nursing follow up has been recognized as a good practice care by patients that should be kept transplantations post-discharge
Innovare la didattica universitaria con Hybrid Blended Learning Solution: Una ricerca design-based project per la formazione iniziale degli insegnanti
The university experience of the pandemic period was fraught with critical issues, but it was also an opportunity to experience digital didactics and learn about its potential. This paper presents a research carried out in academic year 2021-22 in relation to the Teaching Innovation Project for the adoption of a Hybrid Blended Learning Solution (HBLS) model in the master’s degree Course in Primary Education Sciences. Two semi-structured questionnaires were administered to higher education (HE) teachers and students investigating their perceptions of both the HBLS’ effectiveness/quality and its sustainability. Overall, 19 HE teachers (100%) and 364 students (54%) responded to the questionnaire. In both groups, data showed a positive trend of appreciation of the HBLS experience, both in relation to educational quality and sustainability. In a comparative analysis, the perceptions of both samples on sustainability and quality of ICT integration in HBLS aligned. On the other hand, differing perceptions emerge regarding HBLS' impact on educational quality.L’esperienza universitaria del periodo pandemico ha rappresentato una situazione irta di criticità, ma è stata anche un’occasione per fare esperienza di didattica digitale e conoscerne le potenzialità. Questo articolo presenta una ricerca condotta nell'anno accademico 2021-22 in relazione al Progetto di Innovazione didattica per l'adozione di un modello di Hybrid Blended Learning Solution (HBLS) nel corso di laurea magistrale in Scienze della Formazione Primaria. Sono stati somministrati due questionari semi-strutturati a docenti e componente studentesca per indagare le loro percezioni sull'efficacia/qualità HBLS e sulla sua sostenibilità. Complessivamente, hanno risposto al questionario 19 docenti universitari (100%) e 364 studenti (54%). Entrambi i campioni hanno mostrato un trend positivo di apprezzamento dell'esperienza HBLS, sia in relazione alla qualità che alla sua sostenibilità. In un'analisi comparativa, le percezioni di entrambi i campioni su sostenibilità e qualità dell'integrazione delle tecnologie nelle HBLS sono risultate allineate. D'altro canto, emergono percezioni diverse per quanto riguarda l'impatto degli HBLS sulla qualità dell’offerta
Ripensare la didattica in periodo emergenziale: progettualità e sostenibilità dell’integrazione delle tecnologie nella Scuola Primaria e dell’Infanzia
The pandemic represents an unprecedented circumstance, characterized by uncertainty, complexity, and ambiguity that, in its persistence, is triggering scenarios of deep rethinking on the sustainability of the integration of technologies in the school world. Never before has the hoped-for innovation attracted so much attention, even though there is a risk that the many technical difficulties may lead to a widespread failure to grasp the potential and opportunities, reducing the quality of teaching to a mere physical presence. Central is the role of teachers, whose competent action has always been the strategic element to support the meaningfulness of learning, regardless of digital technologies. In this perspective, the article presents an empirical study with a qualitative background aimed at investigating the perceptions of a group of 117 primary and nursery school teachers in the Veneto region on some specific aspects of their ability to reshape teaching. In addition to the perception of critical aspects regarding infrastructural deficiencies and their own preparation, despite the fact that the majority had done specific training even before the emergency, positive signs also emerged from the open-ended responses. The intensive experience of DaD, though extremely complex, was also seen as an opportunity to build relationships with families and the community and to reflect on the importance of methodological renewal to be valued also in the future for the design of integrated digital learning environments.La pandemia rappresenta una circostanza inedita, caratterizzata da incertezza, complessità e ambiguità che, nel suo perdurare, sta innescando scenari di profondo ripensamento sulla sostenibilità dell’integrazione delle tecnologie nel mondo della scuola. Mai come ora l’auspicata innovazione ha sortito attenzione, seppur con il rischio che le molte difficoltà tecniche inducano diffusamente a non coglierne potenzialità e opportunità, riducendo la qualità della didattica alla mera presenza fisica. Centrale è il ruolo degli insegnanti la cui azione competente, da sempre, costituisce l’elemento strategico per supportare la significatività dell’apprendimento, indipendentemente dalle tecnologie digitali. In questa prospettiva, l’articolo presenta uno studio empirico a sfondo qualitativo volto ad indagare le percezioni di un gruppo di 117 docenti di Scuola Primaria e dell’Infanzia del Veneto su alcuni aspetti specifici delle proprie abilità di rimodulazione della didattica. Oltre alla percezione di aspetti critici in merito a carenze infrastrutturali e alla propria preparazione, nonostante la maggioranza abbia fatto formazione specifica anche prima dell'emergenza, dalle risposte aperte sono emersi anche segnali positivi. L'esperienza intensiva della DaD, seppur estremamente complessa, è stata vista anche come occasione per costruire relazioni con le famiglie e la comunità e per riflettere sull'importanza del rinnovamento metodologico da valorizzare anche in futuro per la progettazione di ambienti di apprendimento digitali integrati. 
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