| 1051. |
- Sun, M. D., et al.
(författare)
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New short-lived isotope 223Np and the absence of the Z = 92 subshell closure near N = 126
- 2017
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 771, s. 303-308
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Tidskriftsartikel (refereegranskat)abstract
- The N=130 short-lived isotope 223Np was produced as evaporation residue (ER) in the fusion reaction 40Ar + 187Re at the gas-filled recoil separator Spectrometer for Heavy Atom and Nuclear Structure (SHANS). It was identified through temporal and spatial correlations with α decays of 215Ac and/or 211Fr, the third and fourth members of the α-decay chain starting from 223Np. The pileup signals of ER(223Np)–α(223Np)–α(219Pa) were resolved by using the digital pulse processing technique. An α decay with half-life of T1/2=2.15(52100) μs and energy of Eα=9477(44) keV was attributed to 223Np. Spin and parity of 9/2− were tentatively proposed for the ground state of 223Np by combining the reduced α-decay width and large-scale shell-model calculations. This assignment together with the proton separation energy disprove the existence of a Z=92 subshell closure.
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| 1052. |
- Tadokoro, K., et al.
(författare)
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Problems with irradiators
- 2010
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Ingår i: Vox Sanguinis. - : Wiley. - 0042-9007 .- 1423-0410. ; 98:1, s. 78-84
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Tidskriftsartikel (refereegranskat)
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| 1053. |
- Tahir, M. J., et al.
(författare)
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Internet addiction and sleep quality among medical students during the COVID-19 pandemic : A multinational cross-sectional survey
- 2021
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 16:11 November
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Tidskriftsartikel (refereegranskat)abstract
- Background The emergence of the COVID-19 pandemic has affected the lives of many people, including medical students. The present study explored internet addiction and changes in sleep patterns among medical students during the pandemic and assessed the relationship between them. Methods A cross-sectional study was carried out in seven countries, the Dominican Republic, Egypt, Guyana, India, Mexico, Pakistan, and Sudan, using a convenience sampling technique, an online survey comprising demographic details, information regarding COVID-19, the Pittsburgh Sleep Quality Index (PSQI), and the Internet Addiction Test (IAT). Results In total, 2749 participants completed the questionnaire. Of the total, 67.6% scored above 30 in the IAT, suggesting the presence of an Internet addiction, and 73.5% scored equal and above 5 in the PSQI, suggesting poor sleep quality. Internet addiction was found to be significant predictors of poor sleep quality, causing 13.2% of the variance in poor sleep quality. Participants who reported COVID-19 related symptoms had disturbed sleep and higher internet addiction levels when compared with those who did not. Participants who reported a diagnosis of COVID-19 reported poor sleep quality. Those living with a COVID-19 diagnosed patient reported higher internet addiction and worse sleep quality compared with those who did not have any COVID-19 patients in their surroundings. Conclusion The results of this study suggest that internet addiction and poor sleep quality are two issues that require addressing amongst medical students. Medical training institutions should do their best to minimize their negative impact, particularly during the current COVID-19 pandemic.
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| 1054. |
- Tinyanont, Samaporn, et al.
(författare)
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Supernova 2020wnt : An Atypical Superluminous Supernova with a Hidden Central Engine
- 2023
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 951:1
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Tidskriftsartikel (refereegranskat)abstract
- We present observations of a peculiar hydrogen- and helium-poor stripped-envelope (SE) supernova (SN) 2020wnt, primarily in the optical and near-infrared (near-IR). Its peak absolute bolometric magnitude of −20.9 mag (Lbol, peak = (6.8 ± 0.3) × 1043 erg s−1) and a rise time of 69 days are reminiscent of hydrogen-poor superluminous SNe (SLSNe I), luminous transients potentially powered by spinning-down magnetars. Before the main peak, there is a brief peak lasting <10 days post explosion, likely caused by interaction with circumstellar medium (CSM) ejected ∼years before the SN explosion. The optical spectra near peak lack a hot continuum and O ii absorptions, which are signs of heating from a central engine; they quantitatively resemble those of radioactivity-powered hydrogen/helium-poor Type Ic SESNe. At ∼1 yr after peak, nebular spectra reveal a blue pseudo-continuum and narrow O i recombination lines associated with magnetar heating. Radio observations rule out strong CSM interactions as the dominant energy source at +266 days post peak. Near-IR observations at +200–300 days reveal carbon monoxide and dust formation, which causes a dramatic optical light-curve dip. Pair-instability explosion models predict slow light curve and spectral features incompatible with observations. SN 2020wnt is best explained as a magnetar-powered core-collapse explosion of a 28 M⊙ pre-SN star. The explosion kinetic energy is significantly larger than the magnetar energy at peak, effectively concealing the magnetar-heated inner ejecta until well after peak. SN 2020wnt falls into a continuum between normal SNe Ic and SLSNe I, and demonstrates that optical spectra at peak alone cannot rule out the presence of a central engine.
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| 1055. |
- Van Bavel, Jay J., et al.
(författare)
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National identity predicts public health support during a global pandemic
- 2022
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Ingår i: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Understanding collective behaviour is an important aspect of managing the pandemic response. Here the authors show in a large global study that participants that reported identifying more strongly with their nation reported greater engagement in public health behaviours and support for public health policies in the context of the pandemic. Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = -0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.
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| 1056. |
- Vincent, J. -B, et al.
(författare)
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Are fractured cliffs the source of cometary dust jets? : Insights from OSIRIS/Rosetta at 67P/Churyumov-Gerasimenko
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 587
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Tidskriftsartikel (refereegranskat)abstract
- Context: Dust jets (i.e., fuzzy collimated streams of cometary material arising from the nucleus) have been observed in situ on all comets since the Giotto mission flew by comet 1P/Halley in 1986, and yet their formation mechanism remains unknown. Several solutions have been proposed involving either specific properties of the active areas or the local topography to create and focus the gas and dust flows. While the nucleus morphology seems to be responsible for the larger features, high resolution imagery has shown that broad streams are composed of many smaller jets (a few meters wide) that connect directly to the nucleus surface.Aims: We monitored these jets at high resolution and over several months to understand what the physical processes are that drive their formation and how this affects the surface.Methods: Using many images of the same areas with different viewing angles, we performed a 3-dimensional reconstruction of collimated jets and linked them precisely to their sources on the nucleus.Results: We show here observational evidence that the northern hemisphere jets of comet 67P/Churyumov-Gerasimenko arise from areas with sharp topographic changes and describe the physical processes involved. We propose a model in which active cliffs are the main source of jet-like features and therefore of the regions eroding the fastest on comets. We suggest that this is a common mechanism taking place on all comets.
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| 1057. |
- Vincent, J. -B, et al.
(författare)
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Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography
- 2017
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 469, s. S329-S338
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Tidskriftsartikel (refereegranskat)abstract
- We present a statistical analysis of the distribution of large-scale topographic features on comet 67P/Churyumov-Gerasimenko. We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to -1.69 +/- 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbital erosion rate of the surface. For instance, the Northern hemisphere topography is dominated by structures on the 100 m scale, while the Southern hemisphere topography, illuminated at perihelion, is dominated by 10 m scale terrain features. Our study suggests that the current size of a cliff is controlled not only by material cohesion but also by the dominant erosional process in each region. This observation can be generalized to other comets, where we argue that primitive nuclei are characterized by the presence of large cliffs with a cumulative height-power index equal to or above -1.5, while older, eroded cometary surfaces have a power index equal to or below -2.3. In effect, our model shows that a measure of the topography provides a quantitative assessment of a comet's erosional history, that is, its evolutionary age.
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| 1058. |
- Vincent, J. -B, et al.
(författare)
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Summer fireworks on comet 67P
- 2016
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 462, s. S184-S194
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Tidskriftsartikel (refereegranskat)abstract
- During its 2 yr mission around comet 67P/Churyumov-Gerasimenko, ESA's Rosetta spacecraft had the unique opportunity to follow closely a comet in the most active part of its orbit. Many studies have presented the typical features associated with the activity of the nucleus, such as localized dust and gas jets. Here, we report on series of more energetic transient events observed during the 3 months surrounding the comet's perihelion passage in 2015 August. We detected and characterized 34 outbursts with the Rosetta cameras, one every 2.4 nucleus rotations. We identified three main dust plume morphologies associated with these events: a narrow jet, a broad fan, and more complex plumes featuring both previous types together. These plumes are comparable in scale and temporal variation to what has been observed on other comets. We present a map of the outbursts' source locations, and discuss the associated topography. We find that the spatial distribution sources on the nucleus correlate well with morphological region boundaries, especially in areas marked by steep scarps or cliffs. Outbursts occur either in the early morning or shortly after the local noon, indicating two potential processes: morning outbursts may be triggered by thermal stresses linked to the rapid change of temperature; afternoon events are most likely related to the diurnal or seasonal heat wave reaching volatiles buried under the first surface layer. In addition, we propose that some events can be the result of a completely different mechanism, in which most of the dust is released upon the collapse of a cliff.
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| 1059. |
- Wang, P. -W, et al.
(författare)
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Motivation to have covid-19 vaccination explained using an extended protection motivation theory among university students in china : The role of information sources
- 2021
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Ingår i: Vaccines. - : MDPI. - 2076-393X. ; 9:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: The aims of the present study were to examine the prediction of the threat and coping appraisal utilizing an extended protection motivation theory (PMT) for the motivation to have COVID-19 vaccination and the influence of various information sources on coping appraisal among university students in China. Methods: The sample comprised 3145 students from 43 universities in China who completed an online survey including PMT constructs as well as constructs added to PMT. The PMT constructs comprised motivation to have COVID-19 vaccination, threat appraisal, and coping appraisal. The extended PMT constructs comprised knowledge about mechanisms and information sources of COVID-19 vaccination. Results: Perceived severity of COVID-19 was positively associated with motivation to have COVID-19 vaccination. Receiving information concerning COVID-19 vaccination from medical personnel was associated with greater self-efficacy, response efficacy, and knowledge, whereas receiving information concerning COVID-19 vaccination from coworkers/colleagues was associated with less response efficacy and knowledge. Receiving online information concerning COVID-19 vaccination was associated with greater response cost of vaccination efficacy and less knowledge. Conclusions: This study supported the prediction of perceived severity in the PMT for motivation to have COVID-19 vaccination among university students in China. Vaccination information sources have different effects on students’ coping appraisal of COVID-19 vaccination.
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| 1060. |
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