329 research outputs found

    Metallicity determination of M dwarfs - Expanded parameter range in metallicity and effective temperature

    Full text link
    Context. Reliable metallicity values for M dwarfs are important for studies of the chemical evolution and advancement of planet formation theory in low-mass environments. Historically the determination of stellar parameters of low-mass stars has been challenging due to the low surface temperature, causing several molecules to form in the photospheric layers. In our work we use the fact that infrared high-resolution spectrographs have opened up a new window for investigating M dwarfs. Aims. Metallicity determination using high-resolution spectra is more accurate than the use of low-resolution spectra, but rather time-consuming. In this paper we expand our sample analyzed with this precise method both in metallicity and effective temperature in order to build up a calibration sample for a future revised empirical calibration. Methods. Because of the relatively few molecular lines in the J-band, continuum rectification is possible for high-resolution spectra, allowing the stellar parameters to be determined with greater accuracy than using optical spectra. The metallicity was determined using synthetic spectral fitting of several atomic species. Results. We have analyzed sixteen targets, with a range of effective temperature from 3350-4550 K. The resulting metallicities lie between -0.5 < [M/H] < +0.4. A few targets have previously been analyzed using low-resolution spectra, and we find a rather good agreement with our values. A comparison with available photometric calibrations shows varying agreement, and the spread within all empirical calibrations is large. Conclusions. Including the targets from our previous paper, we have analyzed 28 M dwarfs using high-resolution infrared spectra. The targets spread approximately one dex in metallicity and 1400 K in effective temperature. For individual M dwarfs we achieve uncertainties of 0.05 dex and 100 K on average.Comment: 13 page

    Metallicity determination of M dwarfs - High-resolution IR spectroscopy

    Full text link
    Context. Several new techniques to determine the metallicity of M dwarfs with better precision have been developed over the last decades. However, most of these studies were based on empirical methods. In order to enable detailed abundance analysis, standard methods established for warmer solar-like stars, i.e. model-dependent methods using fitting of synthetic spectra, still need to be used. Aims. In this work we continue the reliability confirmation and development of metallicity determinations of M dwarfs using high- resolution infrared spectra. The reliability was confirmed though analysis of M dwarfs in four binary systems with FGK dwarf companions and by comparison with previous optical studies of the FGK dwarfs. Methods. The metallicity determination was based on spectra taken in the J band (1.1-1.4 {\mu}m) with the CRIRES spectrograph. In this part of the infrared, the density of stellar molecular lines is limited, reducing the amount of blends with atomic lines enabling an accurate continuum placement. Lines of several atomic species were used to determine the stellar metallicity. Results. All binaries show excellent agreement between the derived metallicity of the M dwarf and its binary companion. Our results are also in good agreement with values found in the literature. Furthermore, we propose an alternative way to determine the effective temperature of M dwarfs of spectral types later than M2 through synthetic spectral fitting of the FeH lines in our observed spectra. Conclusions. We have confirmed that a reliable metallicity determination of M dwarfs can be achieved using high-resolution infrared spectroscopy. We also note that metallicites obtained with photometric metallicity calibrations available for M dwarfs only partly agree with the results we obtain from high-resolution spectroscopy.Comment: 18 page

    Spenarnas kondition i automatiska mjölkningssystem : en studie av två spensprayer

    Get PDF
    Two post milkning teat dips (PMTD´s) were compared in an automatic milking system at Kungsängen Research Farm, owned by SLU (Swedish University of Agriculture) in Uppsala. In the experiment an evaluation system was used where teat condition regarding skin and teat ends was graded according to a scale where 1 was the best score and 5 the worst. The evaluation period was almost six months in total devided into four minor experimental periods. The technician scoring the teats did not know which PMTD that was currently used. Statistical analysis showed a significant difference between the two PMTD´s regarding teat skin condition, but not regarding teat ends. Trends within eperimental periods also suggested that one PMTD was preferable compared to the other as teat skin condition improved the longer that period lasted.Två spensprayer har jämförts i ett automatiskt mjölkningssystem för nötkreatur på Kungsängens försöksgård som ägs av SLU (Sveriges Lantbruksuniversitet) i Uppsala. Spenarnas kondition avseende hud och spenspets poängsattes enligt en skala där 1 var bäst och 5 var sämst. Försökstiden uppgick till ca sex månader uppdelat på fyra försöksperioder. En och samma spenspray användes under en och samma försöksperiod. Poängsättaren visste inte vilken spenspray som användes under respektive försöksperiod. Statistisk analys visade en signifikant skillnad mellan de två spensprayerna beträffande spenhudskondition, men inte beträffande spenspetsar. Trender inom försöksperioderna indikerade även att den ena spensprayen var fördelaktig jämfört med den andra då spenhudskonditionen förbättrades ju lägre den perioden pågick

    Close Encounters of the Digital Kind::A Research Agenda for the Digitalization of Public Services

    Get PDF
    This paper contributes to e-government research by presenting a review and discussion on how digitalization of public services has affected the interaction between citizens and government. We argue for a conceptualization and critical reflection on the nature of the underlying interaction between citizens and public officials - the public encounter - that digital public services are developed to support. We apply a qualitative and hermeneutic approach and illustrate that digital public services change public encounters concerning when, where, and how interactions occur, what each actor does, and the skills required of them. By relating these changes to emerging digital technologies (e.g. data mining, machine learning, sensor technology, and service automation), we illustrate that while these new technologies carry the potential to further digitalize service provision and fulfill the democratic goals of digital government, authorities can apply the same technology to restrict, control, and surveil citizens. Based on a critical discussion on what digitalization might entail for society, we identify problem areas arising from this development and propose a research agenda for understanding this phenomenon further. We raise questions and ethical concerns regarding accountability and reskilling of citizens and public officials as public service provision becomes citizen self-service.Funding Agencies|Swedish Transportation Administration; Research Center for Government IT</p

    Посещение Самарского государственного медицинского университета сотрудниками ВГМУ

    Get PDF
    МЕДИЦИНСКИЕ ВУЗЫМЕЖДУНАРОДНОЕ СОТРУДНИЧЕСТВООБРАЗОВАНИЕ МЕДИЦИНСКОЕ /МЕТОДЫПРЕПОДАВАТЕЛИОБРАЗОВАТЕЛЬНЫЙ ПРОЦЕСССТОМАТОЛОГИЧЕСКОЕ ОБРАЗОВАНИЕПРОФЕССИОНАЛЬНОЕ ОБРАЗОВАНИЕВ рамках реализации программы академической мобильности профессорско-преподавательского состава, в соответствии с договором о совместном сотрудничестве между Витебским государственным медицинским университетом и Самарским государственным медицинским университетом в период с 27 по 29 декабря 2016 года сотрудники кафедры терапевтической стоматологии ВГМУ посетили СамГМУ

    Situationism, Honesty, and the Folk

    Get PDF
    This project aims at finding a widespread folk theory of honesty in order to construct an accurate account of the philosophical nature of honesty as a character trait. Our research process involves gathering responses from the folk, then combining and interpreting the responses. Our broad goal is to discover a solid case for the existence of character traits that can be used against the recent situationist attacks being seen in psychology. Proponents of situationism reject the existence of broad character traits, arguing that behaviour is driven by situational factors and that humans posess no significant character traits at all (Harmon, 1999, 2000 and Doris 1998, 2002). Research in psychology has been used to support situationism, but skepticism arises about the interpretation of study results. For example, Kamtekar notes that “[I]t is noteworthy that the experiments appealed by situationists for the most part assume that subjects share the experimenter’s construal of the situation” (2004, p. 471). Our research aims to provide a single, agreed-upon basis for evaluating action in terms of character traits