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Rapidly Rising Transients in the Supernova - Superluminous Supernova Gap
Full text linkThe American Astronomical Society. All rights reserved..We present observations of four rapidly rising (trise ≈ 10 days) transients with peak luminosities between those of supernovae (SNe) and superluminous SNe (Mpeak ap; -20) - one discovered and followed by the Palomar Transient Factory (PTF) and three by the Supernova Legacy Survey. The light curves resemble those of SN 2011kl, recently shown to be associated with an ultra-long-duration gamma-ray burst (GRB), though no GRB was seen to accompany our SNe. The rapid rise to a luminous peak places these events in a unique part of SN phase space, challenging standard SN emission mechanisms. Spectra of the PTF event formally classify it as an SN II due to broad Hα emission, but an unusual absorption feature, which can be interpreted as either high velocity Hα (though deeper than in previously known cases) or Si ii (as seen in SNe Ia), is also observed. We find that existing models of white dwarf detonations, CSM interaction, shock breakout in a wind (or steeper CSM), and magnetar spin down cannot readily explain the observations. We consider the possibility that a "Type 1.5 SN" scenario could be the origin of our events. More detailed models for these kinds of transients and more constraining observations of future such events should help to better determine their nature. © 2016
The psychological and physiological effects of physical activity and fitness in children with type 1 diabetes
No full textMaintenance of blood glucose control and psychological well being are both important health outcomes for children with Type I diabetes. Diabetes management, the balance of insulin, diet and exercise, interacts with all aspects of these children's health, however, to date the effects of exercise in this interaction are poorly understood. This is particularly so with regard to the effects of exercise on psychological health. The aims of the present study were to investigate the effects of physical activity and fitness on the psychological and physiological health of children with Type I diabetes. The hypotheses were 1) that higher levels of physical activity and fitness would be positively associated with both greater psychological well-being and lower HbA,,, 2) that increasing physical activity would increase psychological health and lower HbA,,. Participants were aged 9-15 years, diabetes duration more than 2 years. There were 39 participants in phase one. Physiological data collected were physical activity, aerobic fitness, sum of skinfolds, BMI and HbAjc. Psychological questionnaires used were the physical self perception profile for children, the self efficacy for diabetes scale and the diabetes quality of life for youths questionnaire. Physical self esteem and quality of life were significantly associated with both greater fitness and higher physical activity. There were no significant associations between HbAjc and either fitness or physical activity. Phase two was a randomised controlled trial to evaluate a 12 week physical activity intervention. Thirty-nine children were recruited to this phase, 27 experimental and 12 control, of these 14 experimental and 7 control children completed the study. Data were collected as in phase one. When differences between the groups at time I were taken into account the only significant effect of the intervention was an increase in the BMI of the experimental group. There were increases in the hypothesised direction for aerobic fitness, perceived sports competence and perceived condition competence. Skinfold thickness and self efficacy for diabetes decreased significantly in both groups, strength competence increased significantly in both groups. There was no significant effect on HbA,,. Sample size was small and therefore the results must be treated cautiously due to the possibility of Type 2 error. iii It was concluded that both physical activity and fitness showed positive associations with psychological variables but that a physical activity intervention programme did not lead to significant increases in these variables. It is suggested that an intervention programme that incorporated physical activity and an educational or cognitive component would have a greater effect on the outcomes studied. I
Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material Around <10-Day-Old Type II Supernovae
Full text linkThe American Astronomical Society. All rights reserved.Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude MR = -18.2 belong to the FI or BF groups, and that all FI events peaked above MR = -17.6 mag, significantly brighter than average SNe II
Dendroclimatology of Pinus sylvestris L. in the British Isles
No full textA study of the properties of tree-ring density and ring-width chronologies from five sites in the British Isles, two in Sweden and two sub-fossil sites in Northern Ireland is described. The technique of x-ray densitometry is used to measure density. It is shown that it is possible to use x-ray densitometry on well preserved sub-fossil pine. Chronologies have been constructed for parameters of earlywood and latewood widths, ring-width, maximum and minimum densities for all sites. The statistical properties of chronologies are related to the latitude and altitude of the sites. Sub-fossil chronologies behave differently to any of the living tree chronologies. Response functions on monthly temperature and precipitation data are calculated for the five tree-ring parameters for the living tree chronologies. A principal component analysis involving 25 ring-width chronologies from northwestern Europe is used to examine the spatial relationship between British and European ring-width chronologies. The continuous pattern of density variation across the annual ring is measured for trees from two scottish sites, at Glen Derry and Glen Affric from 1900 to 1979. A method of constructing and comparing annual density profiles by fitting cubic spline functions to the density data is described. This has enabled the effects of growing season climate on density to be examined. The importance of temperature in governing tree-ring density is demonstrated. The use of image analysis techniques to measure the continuous variation in cell dimensions across the annual ring is described. Variations in ring density are explained in terms of changes in wall thickness and lumen diameter. A comprehensive literature review on the physiological mechanisms controlling the response of tree-ring width and density in P. sylvestris to climate is described. The physiological causes-for the climate-growth response in earlywood and latewood widths and densities are summarised seperately. It has been possible to explain some of the results of the response function analysis and the density profile study in terms of physiological processes
Detection of Broad H alpha Emission Lines in the Late-Time Spectra of a Hydrogen-Poor Superluminous Supernova
Full text linkiPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83–148 days to reach a peak bolometric luminosity of ~1.3 × 1044 erg s−1, then decays slowly at 0.015 mag day−1. The measured ejecta velocity is ~ 13,000 km s−1. The inferred explosion characteristics, such as the ejecta mass (70–220 M⊙), and the total radiative and kinetic energy (Erad ~ 1051 erg, Ekin ~ 2 × 1053 erg), are typical of slow-evolving H-poor SLSN events. However, the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmer Hα emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ~4500 km s−1 and a ~300 km s−1 blueward shift relative to the narrow component. We interpret this broad Hα emission with a luminosity of ~2 × 1041 erg s−1 as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ~4 × 1016 cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M⊙. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M⊙ H-shell, ejected from a progenitor star with an initial mass of (95–150) M⊙ about 40 years ago. We estimate that at least ~15% of all SLSNe-I may have late-time Balmer emission lines
DIP Merseyside Drug Testing Report (April 2013 - March 2014)
No full textThe Drug Interventions Programme (DIP) is an initiative set up by the Home Office in 2003 with an overarching aim to break the cycle of drug misuse and crime and as a result reduce acquisitive crime in communities within England and Wales. The DIP process is seen as an important early engagement opportunity, via drug testing, as many of the clients who are assessed for DIP can be some of the most difficult to reach problematic drug users. This report focuses on the seven Merseyside custody suites which carried out drug tests between April 2013 and March 2014, the demographic details captured during the drug testing process and the times at which drug tests were carried out. This report aims to complement the findings from previous reports on this topic in order to provide Merseyside police and local Drug (Alcohol) Action Teams (D(A)AT) with up to date information regarding the clients who are arrested and drug tested, the times of these presentations and outcomes of drug tests carried out in these custody suites
An Evaluation of DIP's impact on offending in Merseyside
Full text linkThis report aimed to provide the Merseyside teams with an assessment of offending outcomes for clients who tested positive between May and July 2011 as part of the Drug Interventions Programme (DIP) and also investigate what critical factors relating to client attributes may have influenced this offending. Findings illustrated in the first instance that across Merseyside, contact with the DIP process as a whole has an extremely positive impact on offending. The client group we examined saw a reduction of 33% in their volume of offending in the 12 months post contact with DIP compared to the 12 months pre. The findings also suggest however that these levels of reduction are not dependent on the level of DIP involvement with the highest reductions seen among those clients who had no further DIP contact following their initial arrest and positive drug test. Nevertheless the data does show the benefits of clients receiving a care plan as a result of their DIP contact, with these clients significantly less likely either re-present to DIP or go to prison in the future than those who were not care planned. Furthermore, clients who had meaningful contact with DIP teams post positive test (i.e. undergoing assessments with DIP workers) were significantly less likely to offend in the future than those without DIP contact. Overall, the report shows that the DIP process and contact with both Merseyside Police and DIP teams contributes substantially to reducing offending and demonstrates the worth of both Test on Arrest and DIP to the overall criminal justice system. Findings were not the same in all areas and teams should consult the discussion chapter in this report for outcomes for their specific area and recommendations where applicable. It should be noted that this piece of work is focused on one of the primary aims of DIP; to reduce offending. It is not the intention of the report to make any suggestion about the impact of DIP intervention on the health or drug use of clients
A tool for integrating time, cost and quality perspectives in Probability Impact (P-I) Tables
No full textOne widely documented tool for project risk analysis is the Probability-Impact (P-I) Table, which assesses the probability of occurrence of a risky event and its likely impact on the project objectives, which are typically articulated in terms of cost, time and quality. Whilst there are numerous adaptations of the P-I Table, they are all consistent in treating the project objectives as independent and unrelated variables. This is a major limitation of the tool and reduces the P-I Table’s practical applicability, as in most project contexts the probabilities and impacts of a risky event on the project objectives will be inter-related. To address this limitation, this paper presents a new tool that uses vector theory to enable a single calculation of the overall probability and impact, incorporating the perspective of all three objectives. The tool is illustrated through a practical application to a real case construction project
Exploring the spectroscopic diversity of type Ia supernovae with DRACULA: a machine learning approach
No full textThe existence of multiple subclasses of type Ia supernovae (SNeIa) has been the subject of great debate in the last decade. One major challenge inevitably met when trying to infer the existence of one or more subclasses is the time consuming, and subjective, process of subclass definition. In this work, we show how machine learning tools facilitate the automatic discovery of sub-populations of SNIa; to that end we introduce the DRACULA Python package (Dimensionality Reduction And Clustering for Unsupervised Learning in Astronomy). Our approach is divided in three steps: (i) Transfer Learning, which takes advantage of all available spectra (even those without an epoch estimate) as an information source, (ii) dimensionality reduction through Deep Learning and (iii) unsupervised learning (clustering) using K-Means. Results match a previously suggested classification scheme, showing that the proposed method is able to grasp the main spectral features behind the definition of such subclasses. Moreover, our methodology is capable of automatically identifying a hierarchical structure of spectral features. This allows the confirmation of the velocity of lines as a first order effect in the determination of SNIa sub-classes, followed by 91bg-like events. In this context, SNIa spectra are described by a space of 4 dimensions + 1 for the time evolution of objects. We interpreted this as evidence that the progenitor system and the explosion mechanism should be described by a small number of initial physical parameters. Given the expected data deluge in the forthcoming years, our proposed approach is essential to allow a quick and statistically coherent identification of subclasses (and outliers). DRACULA is publicly available within COINtoolbox (https://github.com/COINtoolbox/DRACULA)
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