2,995 research outputs found
A Spectropolarimetric Comparison of the Type II-Plateau Supernovae SN 2008bk and SN 2004dj
The Type II-Plateau supernova (SN II-P) SN 2004dj was the first SN II-P for which
spectropolarimetry
data were obtained with fine temporal sampling before, during, and after its fall off of the
photometric plateau – the point that marks the transition from the photospheric to the nebular phase in
SNe II-P. Unpolarized during the plateau, SN 2004dj showed a dramatic spike in polarization during the
descent off of the plateau, and then exhibited a smooth polarization decline over the next two
hundred days. This behavior was interpreted by Leonard et al. (2006) as evidence for a strongly
non-spherical explosion mechanism that had imprinted asphericity only in the innermost ejecta. In this brief
report, we compare nine similarly well-sampled epochs of spectropolarimetry of the Type II-P SN
2008bk to those of SN 2004dj. In contrast to SN 2004dj, SN 2008bk became polarized well before the end
of the plateau and also retained a nearly constant level of polarization through the early nebular
phase. Curiously, although the onset and persistence of polarization differ between the
two objects, the detailed spectropolarimetric characteristics at the epochs of recorded maximum
polarization for the two objects are extremely similar, feature by feature. We briefly interpret the
data in light of non-Local-Thermodynamic Equilibrium, time-dependent radiative-transfer simulations
specifically crafted for SN II-P ejecta
A Spectropolarimetric Comparison of the Type II-Plateau Supernovae SN 2008bk and SN 2004dj
The Type II-Plateau supernova (SN II-P) SN 2004dj was the first SN II-P for
which spectropolarimetry data were obtained with fine temporal sampling before,
during, and after the fall off of the photometric plateau -- the point that
marks the transition from the photospheric to the nebular phase in SNe II-P.
Unpolarized during the plateau, SN 2004dj showed a dramatic spike in
polarization during the descent off of the plateau, and then exhibited a smooth
polarization decline over the next two hundred days. This behavior was
interpreted by Leonard et al. (2006) as evidence for a strongly non-spherical
explosion mechanism that had imprinted asphericity only in the innermost
ejecta. In this brief report, we compare nine similarly well-sampled epochs of
spectropolarimetry of the Type II-P SN 2008bk to those of SN 2004dj. In
contrast to SN 2004dj, SN 2008bk became polarized well before the end of the
plateau and also retained a nearly constant level of polarization through the
early nebular phase. Curiously, although the onset and persistence of
polarization differ between the two objects, the detailed spectropolarimetric
characteristics at the epochs of recorded maximum polarization for the two
objects are extremely similar, feature by feature. We briefly interpret the
data in light of non-Local-Thermodynamic Equilibrium, time-dependent
radiative-transfer simulations specifically crafted for SN II-P ejecta.Comment: 4 pages, 1 figure, to appear in AIP conference proceedings: Stellar
Polarimetry, From Birth to Death, eds. J. Hoffman, B. Whitney, and J.
Bjorkma
El regalo de los quince años: una historia de pasiones, intereses, ideologĂas y luchas
The Gift for a Fifteenth Birthday1: A Story about Passions, Special Interests, Ideologies and Struggles. Since the recovery of democracy in Argentina, the legal situation of minors has been taken into account by juridical agents. The 80’s was a period of discovery of the most flagrant violations of the human rights of children, when legal rules began to be applied that consider them objects of State actions. To incorporate into the scenario the dialogue of the human being, to put forth rights and obligations of the State, leaving behind talk of charity. The inclusion of the Convention on the Rights of Children, its reception in the National Constitution, controversies about the defense of State guardianship and building of the integral protection of rights. The 90’s, with different actors and situations influencing proposed legal modifications. The new century and the hope of achieving legal change as a consequence of new strategies of collective efforts and the conviction of politicians of the need for reform. The new legislation shows us the relationship between the State and children with a focus on respect for family life. A different role for social organizations that work with children, considering how they see and hear the new citizen. Practices conspiring against the effectiveness of the law, the gap between talk and action shows us the long distance that still needs to be covered
Anonymous subject identification and privacy information management in video surveillance
The widespread deployment of surveillance cameras has raised serious privacy concerns, and many privacy-enhancing schemes have been recently proposed to automatically redact images of selected individuals in the surveillance video for protection. Of equal importance are the privacy and efficiency of techniques to first, identify those individuals for privacy protection and second, provide access to original surveillance video contents for security analysis. In this paper, we propose an anonymous subject identification and privacy data management system to be used in privacy-aware video surveillance. The anonymous subject identification system uses iris patterns to identify individuals for privacy protection. Anonymity of the iris-matching process is guaranteed through the use of a garbled-circuit (GC)-based iris matching protocol. A novel GC complexity reduction scheme is proposed by simplifying the iris masking process in the protocol. A user-centric privacy information management system is also proposed that allows subjects to anonymously access their privacy information via their iris patterns. The system is composed of two encrypted-domain protocols: The privacy information encryption protocol encrypts the original video records using the iris pattern acquired during the subject identification phase; the privacy information retrieval protocol allows the video records to be anonymously retrieved through a GC-based iris pattern matching process. Experimental results on a public iris biometric database demonstrate the validity of our framework
On the Progenitor and Supernova of the SN 2002cx-like Supernova 2008ge
We present observations of supernova (SN) 2008ge, which is spectroscopically
similar to the peculiar SN 2002cx, and its pre-explosion site that indicate
that its progenitor was probably a white dwarf. NGC 1527, the host galaxy of SN
2008ge, is an S0 galaxy with no evidence of star formation or massive stars.
Astrometrically matching late-time imaging of SN 2008ge to pre-explosion HST
imaging, we constrain the luminosity of the progenitor star. Since SN 2008ge
has no indication of hydrogen or helium in its spectrum, its progenitor must
have lost its outer layers before exploding, requiring that it be a white
dwarf, a Wolf-Rayet star, or a lower-mass star in a binary system. Observations
of the host galaxy show no signs of individual massive stars, star clusters, or
H II regions at the SN position or anywhere else, making a Wolf-Rayet
progenitor unlikely. Late-time spectroscopy of SN 2008ge show strong [Fe II]
lines with large velocity widths compared to other members of this class at
similar epochs. These previously unseen features indicate that a significant
amount of the SN ejecta is Fe (presumably the result of radioactive decay of
56Ni generated in the SN), further supporting a thermonuclear explosion.
Placing the observations of SN 2008ge in the context of observations of other
objects in the class of SN, we suggest that the progenitor was most likely a
white dwarf.Comment: 9 pages, 6 figures, accepted by A
Awareness of stress-reduction interventions on work attitudes: the impact of tenure and staff group in Australian universities
This study explored the impact of staff group role and length of organizational tenure in the relationship between the awareness of stress interventions (termed intervention awareness: IA) and the work-related attitudinal outcomes of university employees. A two-wave longitudinal study of a sample of 869 employees from 13 universities completed a psychosocial work factors and health questionnaire. Hierarchical regression analyses examined the contribution of staff role and different lengths of organizational tenure with IA and employees' reports of job satisfaction, affective organizational commitment, trust in senior management, and perceived procedural justice. Employees' length of tenure affected the relation between IA and work attitudes, and there were also differences between academic and non-academic staff groups. For non-academic employees, IA predicted job satisfaction, affective organizational commitment, trust in senior management, and perceived procedural justice. However, for academics, IA only predicted job satisfaction and trust which identifies a need to increase the visibility of organizational interventions. Across the tenure groups, IA predicted: (1) perceived procedural justice for employees with five or less years of tenure; (2) job satisfaction for employees with 0-19 years of tenure; (3) trust in senior management for employees with 6-19 years of tenure; and (4) affective organizational commitment for employees with a tenure length of 6-10 years. Employees working at the university for an intermediate period had the most positive perceptions of their organization in terms of IA, job satisfaction, trust in senior management, and affective organizational commitment, whereas employees with 20-38 years of tenure had the least positive perceptions. Results suggest that employees in the middle of their careers report the most positive perceptions of their university. The findings highlight the need to attend to contextual issues in organizational stress and wellbeing interventions and suggest that management may need to implement new strategies and/or promote existing stress-management and reduction strategies to academics, and employees whom are either new to the university or those who have been working for the organization for longer periods of time to ensure that they are aware of organizational strategies to promote employee wellbeing and morale within their work environments.Silvia Pignata, Anthony H. Winefield, Chris Provis and Carolyn M. Boy
Lead accumulation in plants grown in polluted soils. Screening of native species for phytoremediation
In the present work, we focused on soils contaminated with elevated lead concentrations in an agricultural and residential area surrounding a lead smelter plant in Bouwer, province of CĂłrdoba, Argentina. The aim of this research work was to assess the phytoextraction suitability of native plant species growing in the vicinity of a former lead smelter. The lead concentration in leaves, stems and roots was determined in ten species collected at ten sampling sites along a lead concentration gradient in soil. It was found that at circa 1,600 ÎĽg g-1 Pb HCl 0,5 M extractable concentration in soil two native species, Tagetes minuta L. and Bidens pilosa L. accumulated high values of Pb concentration in leaves (380.5 ÎĽg g-1 DW and 100.6 ÎĽg g-1 DW, respectively). Therefore, Tagetes minuta L. and Bidens pilosa L. have a considerable phytoremediation potential for lead polluted soils. At the same sampling site, Sorghum halepense (L.) Pers., a non-native species, only bioconcentrate lead in roots (1,406.8 ÎĽg g-1 DW) showing a phytostabilization potential. The results of this study should be further developed in order to confirm the potential use of these species in soil remediation programs.Fil: Salazar, MarĂa Julieta. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal (p); Argentina. Universidad Nacional de CĂłrdoba; ArgentinaFil: Pignata, MarĂa Luisa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal (p); Argentina. Universidad Nacional de CĂłrdoba; Argentin
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