We present optical and infrared monitoring data of SN 2012hn collected by the Public European Southern Observatory Spectroscopic Survey for Transient Objects. We show that SN 2012hn has a faint peak ...magnitude (M
R
∼ −15.65) and shows no hydrogen and no clear evidence for helium in its spectral evolution. Instead, we detect prominent Ca ii lines at all epochs, which relates this transient to previously described 'Ca-rich' or 'gap' transients. However, the photospheric spectra (from −3 to +32 d with respect to peak) of SN 2012hn show a series of absorption lines which are unique and a red continuum that is likely intrinsic rather than due to extinction. Lines of Ti ii and Cr ii are visible. This may be a temperature effect, which could also explain the red photospheric colour. A nebular spectrum at +150 d shows prominent Ca ii, O i, C i and possibly Mg i lines which appear similar in strength to those displayed by core-collapse supernovae (SNe). To add to the puzzle, SN 2012hn is located at a projected distance of 6 kpc from an E/S0 host and is not close to any obvious star-forming region. Overall SN 2012hn resembles a group of faint H-poor SNe that have been discovered recently and for which a convincing and consistent physical explanation is still missing. They all appear to explode preferentially in remote locations offset from a massive host galaxy with deep limits on any dwarf host galaxies, favouring old progenitor systems. SN 2012hn adds heterogeneity to this sample of objects. We discuss potential explosion channels including He-shell detonations and double detonations of white dwarfs as well as peculiar core-collapse SNe.
The intention of this paper it to open up debate within the environmental modelling and software (EMS) community on how best to respond to the increasing desire to evaluate the success of EMS ...projects in terms of outcomes rather than outputs. Outcomes in these regards are changes beyond the walls of the research organisation (typically to values, attitudes and behaviour). The authors recognise that outcome evaluation is essential in ensuring the relevance and effectiveness of activities. To date, however, there is a limited appreciation within the EMS community of the nature of the challenge inherent in outcome evaluations. The paper presents an exploratory analysis of the challenges that outcome assessment raises for EMS. It does so using mutually reinforcing conceptual and practical perspectives. The paper presents a conceptual framework of three loosely coupled phases – research, development and operations. The nature of activities and their interactions within these phases is outlined and the forms of evaluation associated with each stage set out. The paper notes how existing forms of evaluation (e.g. peer review, validation and relevance) underpin the delivery of outcomes but do not of themselves evaluate outcomes. The paper proposes that outcomes need conceptually to be seen as an element of complex social processes mediated by government, regulation, markets and the media rather than as simply another form of output from research and development projects. As such outcomes of EMS are: less easily tangible than are outputs; more likely to occur at a significant time lag after any intervention; more difficult to assign causality for and to be subject to significant contestation. Thus EMS activity, however well conducted technically, may only have a minor influence on outcomes and EMS practitioners will have limited control over those outcomes that do occur. The paper uses a series of linked EMS projects to populate the conceptual framework showing the role of evaluations in research, development and operations phases. The paper then presents two forms (quantitative and qualitative) of outcome evaluation used as part of an operational phase evaluation of a project communicating the consequences of climate change to remote-rural land managers in Scotland. The authors conclude that while the challenges of EMS evaluation can be met, there needs to be care from the EMS community not to raise expectations of outcomes that cannot be met.
We report extensive observational data for five of the lowest redshift Super-Luminous Type Ic Supernovae (SL-SNe Ic) discovered to date, namely, PTF10hgi, SN2011ke, PTF11rks, SN2011kf, and SN2012il. ...Photometric imaging of the transients at +50 to +230 days after peak combined with host galaxy subtraction reveals a luminous tail phase for four of these SL-SNe. A high-resolution, optical, and near-infrared spectrum from xshooter provides detection of a broad Hei X10830 emission line in the spectrum (+50 days) of SN2012il, revealing that at least some SL-SNe Ic are not completely helium-free. At first sight, the tail luminosity decline rates that we measure are consistent with the radioactive decay of super(56)Co, and would require 1-4 M sub(middot in circle) of super(56)Ni to produce the luminosity. These super(56)Ni masses cannot be made consistent with the short diffusion times at peak, and indeed are insufficient to power the peak luminosity. We instead favor energy deposition by newborn magnetars as the power source for these objects. A semi-analytical diffusion model with energy input from the spin-down of a magnetar reproduces the extensive light curve data well. The model predictions of ejecta velocities and temperatures which are required are in reasonable agreement with those determined from our observations. We derive magnetar energies of 0.4 <, ~ E(10 super(51) erg) <, ~ 6.9 and ejecta masses of 2.3 <, ~ M sub(ej)(M sub(middot in circle)) <, ~ 8.6. The sample of five SL-SNe Ic presented here, combined with SN 2010gx-the best sampled SL-SNe Ic so far-points toward an explosion driven by a magnetar as a viable explanation for all SL-SNe Ic.
Descriptions of the ambivalent role that tourism plays in sustaining fragile environments, communities and cultures are well rehearsed in the tourism literature. Tourism indicators are increasingly ...seen as a way to measure and monitor impacts (both positive and negative) in order to practice adaptive management. Responsible tourism focuses on the choices made by visitors and their hosts, emphasising changing behaviour in order to change tourism outcomes. Thus, responsible tourism provides a particular lens by which to consider how to improve the sustainability of tourism. This paper explores whether a draft sustainable tourism indicator set for one of Scotland's new National Parks measures responsible behaviour (by both tourists and the host communities) and responsible tourism practices. Therefore, the analysis focuses on issues of responsibility for what, by whom and whether the tourism strategy in question will result in responsible tourism. The paper reports our findings and reflects on how the lens of responsible tourism might provide a useful perspective from which to appraise tourism indicators in the future.
The men and women who enter the nation's universities each year are, for that year, the pool of candidates from which Oxford and Cambridge draw undergraduates. This pool is sliced into tranches ...according to A-level score. Oxbridge's achievement in drawing from the pool is measured by its penetration rate (P) of the AAA tranche: this is the number taken from the AAA tranche divided by the total number in the tranche. The Oxbridge mean penetration of the AAA tranche in 1974 was 0.51, and in 1993, 0.38. This drop in the mean value is due to growth of the national AAA tranche by grade inflation at A-level. The significant parameter measuring inequality in Oxbridge admissions is the distribution of cohort penetrations around the mean. In 1974, for the AAA tranche, the extremes were men from independent schools (P = 0.84) and women from state schools (P= 0.30), an indication of extraordinary social and gender inequality. In 1993 gender inequality was essentially nil, and the extremes were men and women from independent schools (P∼ 0.50) and men and women from state schools (P∼0.30). The tranche model for identifying an equality distribution of cohort numbers is based on the principle of equal cohort penetration: this implies that a score of AAA, for example, from a comprehensive school, is as valid for entry to Oxbridge as a score of AAA from an independent school. The equality target numbers for Oxbridge are calculated for each A-level tranche and for each cohort, by multiplying the national cohort numbers in the tranche by the mean tranche penetration. These numbers are then summed over each tranche to yield the equality target numbers for each cohort. The result of this computation is an equality distribution of numbers with the same overall total and the same mean A-level score as the status quo distribution of numbers. The percent change for each cohort from the status quo distribution to achieve equality is then known. In 1974 the only significant changes required were a contraction of ∼ 20% in the independent male cohort numbers to be transferred to state school females. In 1993 the contractions required were of order 8% in both independent school cohorts to be transferred to the state cohorts. The penetration rate is equal to the product of the application rate and the acceptance rate as defined by Robbins. The available data permit a precise calculation of penetration rate but not application rate or acceptance rate. Two steps are proposed to kick-start a rapid increase in the state cohort penetration: (1) the elimination of the interview; (2) the identification of a target for the state entry based on the tranche model to be achieved within a specified period of time.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The academic efficiency and social justice of entry procedures at Oxford and Cambridge Universities are examined over the past quarter of a century. For each major subject the mean A-level scores of ...males and females entering from state and independent schools are compared with mean final examination scores in the major subjects. In any comparison of state and independent cohorts of the same gender, within the bounds of normal statistical fluctuation, the difference in A-level score is a good predictor of the difference in finals score. For example, when between state men and independent men the difference in A-level score is zero, the difference between mean finals score is zero also. The origin of female under-achievement is examined. In most subjects there is pronounced gender inequality due to the following chain of circumstances: (1) to break-even in finals women require at entry better grades at Advanced Level than men; (2) women used to have much the better A-levels and so, in finals a quarter of a century ago, they matched and even - in some subjects - surpassed the men; (3) the A-levels of women entering Oxford and Cambridge Universities fell off during the 1970s; (4) today female A-level scores are slightly worse than male A-level scores, and so female finals scores are much worse, in most subjects, than male finals scores. The concept of an ideal subject is defined; this is a subject in which zero difference in A-level score between male and female yields zero difference in finals score. Law at Cambridge and chemistry at Oxford are ideal subjects. Ideal subjects are rare at Oxbridge: most subjects exhibit a significant male lead in finals when male and female have equal A-level scores. The most non-ideal subject at Oxford is mathematics, in which zero difference in A-level score between males and females yields a male lead in finals score of 13%: at Oxford the other non-ideal subjects are physics (male lead at equal A-levels 11%), philosophy, politics and economics (9%), history (8%), modem languages (8%) and English (5%). An ideal subject is a paradigm which requires even-handedness between male and female cohorts in the following parameters: (1) efficiency of course selection from school; (2) efficiency of teaching; (3) efficiency of finals assessment; (4) latent ability. A pronounced relative decline in the A-level scores of girls educated in state maintained schools entering English and Welsh universities occurred in the 1970s; it is attributed to the reform of the state school system, particularly the growth in mixed-sex comprehensive schools and the decline in the number of female single-sex grammar schools. A peculiar aspect of the admissions filters at both Oxford and Cambridge ensures that state-school educated men gaining entry do so with A-level scores markedly superior to those of the other three cohorts.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The origins of the superior academic performance of men compared with women at Oxford and Cambridge are examined for the years 1987 to 1991, and compared with performance at UK universities excluding ...Oxford and Cambridge over the same years. A Norrington scale (5 for Class 1, 3 for Class 2:1, 2 for Class 2:2, 1 for Class 3) was used to obtain an average score for four cohorts (men and women educated in state schools, men and women educated in independent schools) in each of the major subjects. For UK universities men and women performed roughly equally (men superior in seven subjects, women in six), in good agreement with the observations of Clarke for the years 1976 to 1979. At Oxford men excelled in History, Engineering, Chemistry, Mathematics, Physics, PPE, Law and English: women excelled in no subject: state-school men performed better than independent-school men: independent-school women performed better than state-school women. The abrupt drop in the performance of women, which coincided with the mixing of the colleges at Oxford and Cambridge, is attributed to: (1) lowered efficiency of female selection at admissions (McCrum, 1992); (2) insensitive teaching (Stewart, 1988); (3) the uncongenial undergraduate academic culture of a mixed, formerly male, college (Spurting, 1990). Premenstrual syndrome is considered to have a significant effect on the gender deficit, particularly when the examination schedule is intensive.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The focus of this thesis is the study of superluminous supernovae (SLSNe) within the Pan- STARRSI Medium Deep Survey (PSI MDS). Previous work on SLSNe has displayed a trend in their host ...environments, in that they seem to preferentially occur in low luminosity or dwarf galaxies. This presented the motivation to search for supernovae in faint host galaxies in the hope of finding new SLSNe. The PS 1 MDS offered an ideal experiment for such a search, in the redshift range z = 0.3 - 1.5. During the 3 year period of study, approximately 400 PSI MDS hostless transients were catalogued and around half classified. Of the 22 spectroscopically confirmed supernovae which were not of Type la, over 50% have been classified as likely SLSNe. This led to the discovery and detailed study of PS1-11ap (in a faint host galaxy at z = 0.524). The object was discovered at the start of an observing season resulting in a superbly sampled light curve. Rest frame UV and optical spectra were obtained throughout its observing season, including a host spectrum. From comparisons with known SLSNe and modelling of a composite bolometric light curve a confident classification of PS 1-11ap as a rare, slowly evolving SLSNe-Ic is made. PSI-lOpm and PSI-I0ahf, at z = 1.206 and z = 1.158, were also discovered. Spectroscopic and photometric comparisons of PSI-lOpm with SLSNe-Ic place it comfortably within this class . PSI-lOahf sits better as a slowly evolving SLSN-Ic, however alternative progenitor possibilities are presented. A single spectrum and appropriate photometric magnitude for PS1-11acn (z = 0.61) offer limited evidence for SLSN typing. Rates for the two SLSNe-Ic classes are also estimated using Monte-Carlo simulations, at around 10"-4 and 10"-5 that of the normal CCSNe rate.
PDF
