8,311 research outputs found

    Social science data repositories in data deluge A case study of ICPSR's workflow and practices

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    Purpose - Owing to the recent surge of interest in the age of the data deluge, the importance of researching data infrastructures is increasing. The open archival information system (OAIS) model has been widely adopted as a framework for creating and maintaining digital repositories. Considering that OAIS is a reference model that requires customization for actual practice, this paper aims to examine how the current practices in a data repository map to the OAIS environment and functional components. Design/methodology/approach - The authors conducted two focus-group sessions and one individual interview with eight employees at the world's largest social science data repository, the Interuniversity Consortium for Political and Social Research (ICPSR). By examining their current actions (activities regarding their work responsibilities) and IT practices, they studied the barriers and challenges of archiving and curating qualitative data at ICPSR. Findings - The authors observed that the OAIS model is robust and reliable in actual service processes for data curation and data archives. In addition, a data repository's workflow resembles digital archives or even digital libraries. On the other hand, they find that the cost of preventing disclosure risk and a lack of agreement on the standards of text data files are the most apparent obstacles for data curation professionals to handle qualitative data; the maturation of data metrics seems to be a promising solution to several challenges in social science data sharing. Originality/value - The authors evaluated the gap between a research data repository's current practices and the adoption of the OAIS model. They also identified answers to questions such as how current technological infrastructure in a leading data repository such as ICPSR supports their daily operations, what the ideal technologies in those data repositories would be and the associated challenges that accompany these ideal technologies. Most importantly, they helped to prioritize challenges and barriers from the data curator's perspective and to contribute implications of data sharing and reuse in social sciences

    Pulsed THz radiation due to phonon-polariton effect in [110] ZnTe crystal

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    Pulsed terahertz (THz) radiation, generated through optical rectification (OR) by exciting [110] ZnTe crystal with ultrafast optical pulses, typically consists of only a few cycles of electromagnetic field oscillations with a duration about a couple of picoseconds. However, it is possible, under appropriate conditions, to generate a long damped oscillation tail (LDOT) following the main cycles. The LDOT can last tens of picoseconds and its Fourier transform shows a higher and narrower frequency peak than that of the main pulse. We have demonstrated that the generation of the LDOT depends on both the duration of the optical pulse and its central wavelength. Furthermore, we have also performed theoretical calculations based upon the OR effect coupled with the phonon-polariton mode of ZnTe and obtained theoretical THz waveforms in good agreement with our experimental observation.Comment: 9 pages, 5 figure

    Models of Social Groups in Blogosphere Based on Information about Comment Addressees and Sentiments

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    This work concerns the analysis of number, sizes and other characteristics of groups identified in the blogosphere using a set of models identifying social relations. These models differ regarding identification of social relations, influenced by methods of classifying the addressee of the comments (they are either the post author or the author of a comment on which this comment is directly addressing) and by a sentiment calculated for comments considering the statistics of words present and connotation. The state of a selected blog portal was analyzed in sequential, partly overlapping time intervals. Groups in each interval were identified using a version of the CPM algorithm, on the basis of them, stable groups, existing for at least a minimal assumed duration of time, were identified.Comment: Gliwa B., Ko\'zlak J., Zygmunt A., Models of Social Groups in Blogosphere Based on Information about Comment Addressees and Sentiments, in the K. Aberer et al. (Eds.): SocInfo 2012, LNCS 7710, pp. 475-488, Best Paper Awar

    Optimized Formation of Benzyl Isothiocyanate by Endogenous Enzyme and its Extraction from Carica Papaya Seed

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    Purpose: To use endogenous myrosinase in Carica papaya seed to convert benzyl glucosinolate (BG) to benzyl isothiocyanate (BITC) and then extract it for further studies.Methods: Process variables including seed powder particle size, sample-to-solvent ratio, pH of buffer solution, enzymolysis temperature, enzymolysis time were investigated using single-factor experiments and response surface methodology coupled with Box-Behnken design for further optimization of conversion conditions. The formed benzyl  isothiocyanate was extracted by steam distillation method and purified by thin-layer chromatography (TLC). Relevant process variables were also studied. Finally, the purified benzyl isothiocyanate was analyzed by gas chromatography-mass spectrometer (GC-MS) and compared to BITC standard.Results: Optimum enzymolysis conditions were seed powder particle size, 90 - 120 µm; sample-tosolvent ratio, 1:20; pH of buffer solution, 4.8; enzymolysis temperature, 40 0C; and enzymolysis time, 27 min.  Enzymolysis liquid was steam-distilled for 2 h, extracted twice using  dichloromethane (DCM) (using 3 times the volume of distillate each time) as extractant. Finally, 1:20 was adopted as the optimal dichloromethane-petroleum ether (DCM-PE) elution proportion to wash out the unnecessarycompounds.Conclusion: The result showed that benzyl isothiocyanate was formed under the optimized conditions and was no doubt the basic component of the extraction.Keywords: Carica papaya, Benzyl isothiocyanate, Endogenous myrosinase, Enzymolysis, Extractio

    UTJECAJ RELIGIOZNOSTI I DUHOVNOSTI NA SVAKODNEVNU PRAKSU SOCIJALNIH RADNIKA

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    Although social work can trace the roots of its establishment as a profession to religion/spirituality, the relationship between social work and religion/spirituality has deteriorated due to the former’s professionalisation and secularisation. Nevertheless, religious/spiritual values are important for many social work services and for the practice of the profession. It is, hence, worth demarcating the role of religion/spirituality for frontline social workers. In the current qualitative study, repeated interviews were conducted with 11 Chinese social workers from diverse social work settings. It was noted that Eastern and Western religion/spirituality can instil meaning and value in the profession’s nature.Iako se uspostavljanje socijalnog rada kao profesije temelji na religIoznosti/duhovnosti, odnos između socijalnog rada i religioznosti/duhovnosti narušen je zbog profesionalizacije i sekularizacije socijalnog rada. Usprkos tome, religiozne/duhovne vrijednosti važne su za mnoge usluge socijalnog rada i za praksu socijalnog rada kao profesije. Stoga je važno utvrditi ulogu religioznosti/duhovnosti za najizloženije socijalne radnike. U ovom kvalitativnom istraživanju provedeni su ponovljeni razgovori s 11 kineskih socijalnih radnika iz različitih područja socijalnog rada. Uočeno je da istočnjačka i zapadnjačka religioznost/duhovnost mogu unijeti značenje i vrijednost u prirodu profesije

    Robust pinning of magnetic moments in pyrochlore iridates

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    Pyrochlore iridates A2Ir2O7 (A = rare earth elements, Y or Bi) hold great promise for realizing novel electronic and magnetic states owing to the interplay of spin-orbit coupling, electron correlation and geometrical frustration. A prominent example is the formation of all-in/all-out (AIAO)antiferromagnetic order in the Ir4+ sublattice that comprises of corner-sharing tetrahedra. Here we report on an unusual magnetic phenomenon, namely a cooling-field induced shift of magnetic hysteresis loop along magnetization axis, and its possible origin in pyrochlore iridates with non-magnetic Ir defects (e.g. Ir3+). In a simple model, we attribute the magnetic hysteresis loop to the formation of ferromagnetic droplets in the AIAO antiferromagnetic background. The weak ferromagnetism originates from canted antiferromagnetic order of the Ir4+ moments surrounding each non-magnetic Ir defect. The shift of hysteresis loop can be understood quantitatively based on an exchange-bias like effect in which the moments at the shell of the FM droplets are pinned by the AIAO AFM background via mainly the Heisenberg (J) and Dzyaloshinsky-Moriya (D) interactions. The magnetic pinning is stable and robust against the sweeping cycle and sweeping field up to 35 T, which is possibly related to the magnetic octupolar nature of the AIAO order.Comment: 16 pages, 4 figure
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