In this work, BVRI light curves of 55 Type II supernovae (SNe II) from the Lick Observatory Supernova Search programme obtained with the Katzman Automatic Imaging Telescope and the 1 m Nickel ...telescope from 2006 to 2018 are presented. Additionally, more than 150 spectra gathered with the 3 m Shane telescope are published. We conduct an analyse of the peak absolute magnitudes, decline rates, and time durations of different phases of the light and colour curves. Typically, our light curves are sampled with a median cadence of 5.5 d for a total of 5093 photometric points. In average, V-band plateau declines with a rate of 1.29 mag (100 d)(exp −1), which is consistent with previously published samples. For each band, the plateau slope correlates with the plateau length and the absolute peak magnitude: SNe II with steeper decline have shorter plateau duration and are brighter. A time-evolution analysis of spectral lines in term of velocities and pseudo-equivalent widths is also presented in this paper. Our spectroscopic sample ranges between 1 and 200 d post-explosion and has a median ejecta expansion velocity at 50 d post-explosion of 6500 km s(exp −1) (H α line) and a standard dispersion of 2000 km s(exp −1). Nebular spectra are in good agreement with theoretical models using a progenitor star having a mass <16M⨀. All the data are available to the community and will help to understand SN II diversity better, and therefore to improve their utility as cosmological distance indicators.
Structures in the Outer Solar Atmosphere Fletcher, L.; Cargill, P. J.; Antiochos, S. K. ...
Space science reviews,
05/2015, Letnik:
188, Številka:
1-4
Journal Article
Recenzirano
Odprti dostop
The structure and dynamics of the outer solar atmosphere are reviewed with emphasis on the role played by the magnetic field. Contemporary observations that focus on high resolution imaging over a ...range of temperatures, as well as UV, EUV and hard X-ray spectroscopy, demonstrate the presence of a vast range of temporal and spatial scales, mass motions, and particle energies present. By focusing on recent developments in the chromosphere, corona and solar wind, it is shown that small scale processes, in particular magnetic reconnection, play a central role in determining the large-scale structure and properties of all regions. This coupling of scales is central to understanding the atmosphere, yet poses formidable challenges for theoretical models.
In this paper, a methodology for the ongoing diagnosis and facilitation (when required) of organizational change management programmes in an Australian University is described. The application of ...this methodology on an annual basis requires the assessment of research attitudes and behaviour, areas that have assumed considerable importance within universities around the world in the last decade. This increasing importance associated with research stems in part (a significant part) from the linkage of research quantum (output) of universities to their funding from government. The methodology developed in this paper embraces a wide range of OR-type techniques as well as a range of change management tools from human resources management. These two sets of techniques and tools work together as tools in their own right as well as providing the infrastructure to achieve the objectives. The developed methodology is an interesting blend of hard techniques and 'soft' approaches implemented through a soft heuristic, indeed this application is an example of mixed-mode modelling. The OR techniques (conventional in both their nature and application) are comprised of social judgement theory (for bench-marking research attitudes) and integer linear programming (for setting research targets). The results of the application of the developed methodology are discussed in terms of the effect on research quantum over a 5-year period. A similar methodology could be developed for a change process covering aspects of an organization other than research output in a number of countries.
Molecular phylogenetic analyses of hornworts were performed on a nucleotide data set consisting of mitochondrial nad5, chloroplast rbcL and nuclear 18S gene regions. Thirty-seven hornworts ...representing most of the named generic segregates and morphological diversity in the group were sampled for the three gene analysis while an additional 25 samples were included in an analysis of rbcL alone. Results of these analyses confirm the relationships observed in prior molecular studies but also reveal a number of previously unrecognized yet highly supported clades. On the basis of this and continued morphological and ultrastructural investigations we propose a revised classification of the hornworts. At the highest levels, five well-supported clades are demonstrated and they include: 1) Leiosporoceros, which in most analyses is sister to the remaining hornworts; 2) Anthoceros, Folioceros and Sphaerosporoceros; 3) Notothylas and Phaeoceros; 4) Phymatoceros, a recently described genus that contains two species previously included in Phaeoceros; and 5) the remaining hornwort genera: Megaceros, Dendroceros, Nothoceros and a new genus, Phaeomegaceros. Challenges for continued studies that focus on hornwort systematics include obtaining live specimens worldwide and sorting through the chaotic taxonomy within the group. Morphological studies are hindered by poor preservation of existing collections, and the lack of background data and expertise in hornwort biology. Likewise, molecular sequence data are challenged by the deep divergences and potential effects of extensive RNA editing on phylogenetic reconstruction. Future directions for hornwort systematic studies include accumulating gene sequence data that resolve interspecific relationships and comparative anatomical/ultrastructural work that further elucidates biodiversity in the group. Our ongoing, interdisciplinary studies will culminate in a comprehensive analysis that combines molecular and morphological data for a total evidence approach.
In this work, BV RI light curves of 55 Type II supernovae (SNe II) from the Lick Observatory Supernova Search program obtained with the Katzman Automatic Imaging Telescope and the 1 m Nickel ...telescope from 2006 to 2018 are presented. Additionally, more than 150 spectra gathered with the 3 m Shane telescope are published. We conduct an analyse of the peak absolute magnitudes, decline rates, and time durations of different phases of the light and colour curves. Typically, our light curves are sampled with a median cadence of 5.5 days for a total of 5093 photometric points. In average V-band plateau declines with a rate of 1.29 mag (100 days)-1, which is consistent with previously published samples. For each band, the plateau slope correlates with the plateau length and the absolute peak magnitude: SNe II with steeper decline have shorter plateau duration and are brighter. A time-evolution analysis of spectral lines in term of velocities and pseudoequivalent widths is also presented in this paper. Our spectroscopic sample ranges between 1 and 200 days post-explosion and has a median ejecta expansion velocity at 50 days post-explosion of 6500 km/s (Halpha line) and a standard dispersion of 2000 km/s. Nebular spectra are in good agreement with theoretical models using a progenitor star having a mass <16 Msol. All the data are available to the community and will help to understand SN II diversity better, and therefore to improve their utility as cosmological distance indicators.
Australia's 2019-2020 'Black Summer' bushfires burnt more than 8 million hectares of vegetation across the south-east of the continent, an event unprecedented in the last 200 years. Here we report ...the impacts of these fires on vascular plant species and communities. Using a map of the fires generated from remotely sensed hotspot data we show that, across 11 Australian bioregions, 17 major native vegetation groups were severely burnt, and up to 67-83% of globally significant rainforests and eucalypt forests and woodlands. Based on geocoded species occurrence data we estimate that >50% of known populations or ranges of 816 native vascular plant species were burnt during the fires, including more than 100 species with geographic ranges more than 500 km across. Habitat and fire response data show that most affected species are resilient to fire. However, the massive biogeographic, demographic and taxonomic breadth of impacts of the 2019-2020 fires may leave some ecosystems, particularly relictual Gondwanan rainforests, susceptible to regeneration failure and landscape-scale decline.
Drawing on empirical research, clinical case material and vivid examples from modern culture, The Psychology of Overeating demonstrates that overeating must be understood as part of the wider ...cultural problem of consumption and materialism. Highlighting modern society’s pathological need to consume, Kima Cargill explores how our limitless consumer culture offers an endless array of delicious food as well as easy money whilst obscuring the long-term effects of overconsumption. The book investigates how developments in food science, branding and marketing have transformed Western diets and how the food industry employs psychology to trick us into eating more and more – and why we let them. Drawing striking parallels between ‘Big Food’ and ‘Big Pharma’, Cargill shows how both industries use similar tactics to manufacture desire, resist regulation and convince us that the solution to overconsumption is further consumption. Real-life examples illustrate how loneliness, depression and lack of purpose help to drive consumption, and how this is attributed to individual failure rather than wider culture. The first book to introduce a clinical and existential psychology perspective into the field of food studies, Cargill’s interdisciplinary approach bridges the gulf between theory and practice. Key reading for students and researchers in food studies, psychology, health and nutrition and anyone wishing to learn more about the relationship between food and consumption.
ABSTRACT For the first time, we demonstrate how an MHD avalanche might occur in a multithreaded coronal loop. Considering 23 non-potential magnetic threads within a loop, we use 3D MHD simulations to ...show that only one thread needs to be unstable in order to start an avalanche even when the others are below marginal stability. This has significant implications for coronal heating in that it provides for energy dissipation with a trigger mechanism. The instability of the unstable thread follows the evolution determined in many earlier investigations. However, once one stable thread is disrupted, it coalesces with a neighboring thread and this process disrupts other nearby threads. Coalescence with these disrupted threads then occurs leading to the disruption of yet more threads as the avalanche develops. Magnetic energy is released in discrete bursts as the surrounding stable threads are disrupted. The volume integrated heating, as a function of time, shows short spikes suggesting that the temporal form of the heating is more like that of nanoflares than of constant heating.
We performed a multitiered, case-control association study of psoriasis in three independent sample sets of white North American individuals (1,446 cases and 1,432 controls) with 25,215 genecentric ...single-nucleotide polymorphisms (SNPs) and found a highly significant association with an
IL12B 3′-untranslated-region SNP (
rs3212227), confirming the results of a small Japanese study. This SNP was significant in all three sample sets (odds ratio OR
common 0.64, combined
P P
comb=7.85×10
−10). A Monte Carlo simulation to address multiple testing suggests that this association is not a type I error. The coding regions of
IL12B were resequenced in 96 individuals with psoriasis, and 30 additional
IL12B-region SNPs were genotyped. Haplotypes were estimated, and genotype-conditioned analyses identified a second risk allele (
rs6887695) located ∼60 kb upstream of the
IL12B coding region that exhibited association with psoriasis after adjustment for
rs3212227. Together, these two SNPs mark a common
IL12B risk haplotype (OR
common 1.40,
P
comb=8.11×10
−9) and a less frequent protective haplotype (OR
common 0.58,
P
comb=5.65×10
−12), which were statistically significant in all three studies. Since
IL12B encodes the common IL-12p40 subunit of IL-12 and IL-23, we individually genotyped 17 SNPs in the genes encoding the other chains of these cytokines (
IL12A and
IL23A) and their receptors (
IL12RB1, IL12RB2, and
IL23R). Haplotype analyses identified two
IL23R missense SNPs that together mark a common psoriasis-associated haplotype in all three studies (OR
common 1.44,
P
comb=3.13×10
−6). Individuals homozygous for both the
IL12B and the
IL23R predisposing haplotypes have an increased risk of disease (OR
common 1.66,
P
comb=1.33×10
−8). These data, and the previous observation that administration of an antibody specific for the IL-12p40 subunit to patients with psoriasis is highly efficacious, suggest that these genes play a fundamental role in psoriasis pathogenesis.
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