161 research outputs found
A Carbon/Oxygen-dominated Atmosphere Days after Explosion for the "Super-Chandrasekhar" Type Ia SN 2020esm
No full textSeeing pristine material from the donor star in a type Ia supernova (SN Ia) explosion can reveal the nature of the binary system. In this paper, we present photometric and spectroscopic observations of SN 2020esm, one of the best-studied SNe of the class of "super-Chandrasekhar" SNe Ia (SC SNe Ia), with data obtained 12 to +360 days relative to peak brightness, obtained from a variety of ground- and space-based telescopes. Initially misclassified as a type II supernova, SN 2020esm peaked at M-B = -19.9 mag, declined slowly (Delta m(15)(B) = 0.92 mag), and had particularly blue UV and optical colors at early times. Photometrically and spectroscopically, SN 2020esm evolved similarly to other SC SNe Ia, showing the usual low ejecta velocities, weak intermediate-mass elements, and the enhanced fading at late times, but its early spectra are unique. Our first few spectra (corresponding to a phase of greater than or similar to 10 days before peak) reveal a nearly pure carbon/oxygen atmosphere during the first days after explosion. This composition can only be produced by pristine material, relatively unaffected by nuclear burning. The lack of H and He may further indicate that SN 2020esm is the outcome of the merger of two carbon/oxygen white dwarfs. Modeling its bolometric light curve, we find an Ni-56 mass of 1.23(-0.14)(+0.14) M-circle dot and an ejecta mass of 1.75(-0.20)(+0.32)M(circle dot), in excess of the Chandrasekhar mass. Finally, we discuss possible progenitor systems and explosion mechanisms of SN 2020esm and, in general, the SC SNe Ia class.</p
Cooling rates of neutron stars and the young neutron star in the Cassiopeia A supernova remnant
No full textWe explore the thermal state of the neutron star in the Cassiopeia A supernova remnant using the recent result of Ho & Heinke that the thermal radiation of this star is well described by a carbon atmosphere model and the emission comes from the entire stellar surface. Starting from neutron star cooling theory, we formulate a robust method to extract neutrino cooling rates of thermally relaxed stars at the neutrino cooling stage from observations of thermal surface radiation. We show how to compare these rates with the rates of standard candles – stars with non-superfluid nucleon cores cooling slowly via the modified Urca process. We find that the internal temperature of standard candles is a well-defined function of the stellar compactness parameter x=rg/R, irrespective of the equation of state of neutron star matter (R and rg are circumferential and gravitational radii, respectively). We demonstrate that the data on the Cassiopeia A neutron star can be explained in terms of three parameters: f?, the neutrino cooling efficiency with respect to the standard candle; the compactness x; and the amount of light elements in the heat-blanketing envelope. For an ordinary (iron) heat-blanketing envelope or a low-mass (? 10?13 M?) carbon envelope, we find the efficiency f?? 1 (standard cooling) for x? 0.5 and f?? 0.02 (slower cooling) for a maximum compactness x? 0.7. A heat blanket containing the maximum mass (?10?8 M?) of light elements increases f? by a factor of 50. We also examine the (unlikely) possibility that the star is still thermally non-relaxe
XMM-Newton observation of the highly magnetised accreting pulsar Swift J045106.8-694803: evidence of a hot thermal excess
No full textSeveral persistent, low luminosity (LX ~ 1034 erg s-1), long spin period (P > 100 s) High Mass X-ray Binaries have been reported with blackbody components with temperatures > 1 keV. These hot thermal excesses have correspondingly small emitting regions (< 1 km2) and are attributed to the neutron star polar caps. We present a recent XMM-Newton target of opportunity observation of the newest member of this class, Swift J045106.8-694803. The period was determined to be 168.5 ± 0.2 s as of 17 July 2012 (MJD = 56125.0). At LX ~ 1036 erg s-1, Swift J045106.8-694803 is the brightest member of this new class, as well as the one with the shortest period. The spectral analysis reveals for the first time the presence of a blackbody with temperature kTBB = 1.8 +0.2-0.3 keV and radius RBB = 0.5 ± 0.2 km. The pulsed fraction decreases with increasing energy and the ratio between the hard (> 2 keV) and soft (< 2 keV) light curves is anticorrelated with the pulse profile. Simulations of the spectrum suggest that this is caused by the pulsations of the blackbody being ~ π out of phase with those of the power law component. Using a simple model for emission from hot spots on the neutron star surface, we fit the pulse profile of the blackbody component to obtain an indication of the geometry of the system
Cataclysmic variables from a ROSAT/2MASS selection. I, Four new intermediate polars
No full textWe report the first results from a new search for cataclysmic variables (CVs) using a combined X-ray (ROSAT)/infrared (2MASS) target selection that discriminates against background active galactic nuclei. Identification spectra were obtained at the Isaac Newton Telescope for a total of 174 targets, leading to the discovery of 12 new CVs. Initially devised to find short-period low-mass-transfer CVs, this selection scheme has been very successful in identifying new intermediate polars. Photometric and spectroscopic follow-up observations identify four of the new CVs as intermediate polars: 1RXS J063631.9+353537 P(orb)similar or equal to 201 min, P-spin= 1008.3408 s or 930.5829 s), 1RXS J070407.9+262501 (P(orb)similar or equal to 250 min, P-spin= 480.708 s) 1RXS J173021.5-055933 (P-orb= 925.27 min, P-spin= 128.0 s), and 1RXS J180340.0+401214 (P-orb= 160.21 min, P-spin= 1520.51 s). RX J1730, also a moderately bright hard X-ray source in the INTEGRAL/IBIS Galactic plane survey, resembles the enigmatic AE Aqr. It is likely that its white dwarf is not rotating at the spin equilibrium period, and the system may represent a short-lived phase in CV evolution
Constraining Type Ia Supernova Progenitor Scenarios with Extremely Late-time Photometry of Supernova SN 2013aa
No full text"Disney is the Tiffany’s and I am the Woolworth's of the business": A critical re-analysis of the business philosophies, production values and studio practices of animator-producer Paul Houlton Terry
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Animator-producer Paul Houlton Terry has been portrayed as having little passion for the animation he produced and being more concerned with making a profit than producing entertaining cartoons with high production values. The purpose of the dissertation is to re-evaluate Terry‘s legacy to animated cartooning by analyzing his business philosophies, production values, and studio practices.
Application of four psychodynamic factors to the early life and career of Terry, 1887-1929, found that his economic decision making was characterized by: an external locus of control, risk-averse financial behaviour, extreme saving behaviour through precaution, and shrewd money management practices. Based on Terry‘s historical responses to twelve major economic, technological, or institutional forces of change for the period 1929-1955, the psychodynamic factors were found to provide accurate explanations for his studio practices and production decisions.
There was no evidence to support the conclusion that three early career disappointments undermined Terry‘s intrinsic motivation to create animated cartoons. Rather, Terry‘s lack of risk taking, external locus of control, tight studio production schedule, desire to compete with neighbour studio Fleischer, difficulty in separating financial rewards from creative processes in animation, and practice of undertaking surveillance measures on staff may have undermined his and his studio‘s creativity. Archival research found Terry to possess strong passions for and to have made significant creative contributions to the field of animation.
Biographical research found that Terry retained a stable nucleus of highly talented artists who dedicated a significant portion of their working careers to the studio. An analysis of the cel aesthetics of a random sample of animated cartoons produced during the years 1930-1955 found that Terry created animated cartoons with above average cel aesthetics when compared to the other studios thereby supporting an inference that Terry was motivated to producing quality crafted animation. Further research is suggested into the role psychodynamic factors and economic decision-making play in the film production process and a clarification of Terry‘s legacy to the field of animated cartoons
Advancing Your Confidence as an Educator (ACE): An academic-VA partnership to enhance educator skills and improve attitudes about careers in aging [advanced online publication]
No full textPrevious research suggests some psychologists may not consider academic careers because of doubts about their teaching competency, and this is especially true for psychologists interested in aging (i.e., geropsychologists). To enhance competencies in the practice of education, we developed a webinar series, Advancing Your Confidence as an Educator, to bolster skills and attitudes toward teaching and improve attitudes about careers in aging. Seven hour-long webinars addressed key skills in developing and executing courses and professional presentations, and 2 panel sessions addressed attitudes toward teaching by featuring early- and later-career professionals discussing their paths to and satisfaction with jobs as educators. Attendance across the highly interactive sessions was robust (M = 50). Evaluation data suggest the webinar was effective in meeting educational needs. To promote sustainable impact, the webinars are archived and freely available online. Challenges in marketing and evaluation arose, but overall, this effort is one way of cultivating a more vigorous interest and self-confidence in teaching
AN OVERVIEW OF NEEDS THEORIES BEHIND CONSUMERISM
No full textWynn and Coolidge [2004] have hypothesized that one of the key reasons why the Homo Sapiens progressed to being modern man while the Neanderthal man didn�t, is that the former developed through innovation (from artefacts to advanced hunting methods) while the latter has left no trace of such evolution. Almost as if the Neanderthal man did not see the need to progress and accepted circumstances as fact. If this is true then the Homo Sapiens have not only developed psychological and objective needs but have progressively updated them as well. Maslow put it beautifully by saying �You will either step forward into growth, or you will step backward into safety�. This paper is the first part of a two part series. Here we provide an overview of needs theories and discuss them in the context of consumerism, consumption and opportunities for enterprises. In part two, needs and opportunities are linked to markets, benefits and strategies through a specific 3D model based on Maslow�s pyramid. To pave the way for this approach we also promote a model (PIE-Persons, Institutions and Enterprises) with the intent to help enterprises view consumers, institutions and their organisation as one interweaved entity. Needs theories are known to be crucial behind much of the understanding of human behaviour and in particular in the workplace and by the consumer. This paper examines the development of hierarchical needs theory from Maslow to Gough with the intent to better identify consumer needs, provide examples of current and past business opportunities and macroscopically show the progression from red to blue ocean strategies. The authors provide an overview of needs theories seeded through motivational theory also with the aim to uncover the differences in having (sometimes known as deficit needs) and being needs (sometimes known as growth needs) and then subsequently link them to enterprise strategies, improved consumer understanding and better market exploitation.Maslow, Herzberg, needs, motivation, having, being, uniformity, diversity
An Overview of Needs Theories behind Consumerism
No full textWynn and Coolidge [2004] have hypothesized that one of the key reasons why the Homo Sapiens progressed to being modern man while the Neanderthal man didn’t, is that the former developed through innovation (from artefacts to advanced hunting methods) while the latter has left no trace of such evolution. Almost as if the Neanderthal man did not see the need to progress and accepted circumstances as fact. If this is true then the Homo Sapiens have not only developed psychological and objective needs but have progressively updated them as well. Maslow put it beautifully by saying “You will either step forward into growth, or you will step backward into safety”. This paper is the first part of a two part series. Here we provide an overview of needs theories and discuss them in the context of consumerism, consumption and opportunities for enterprises. In part two, needs and opportunities are linked to markets, benefits and strategies through a specific 3D model based on Maslow’s pyramid. To pave the way for this approach we also promote a model (PIE-Persons, Institutions and Enterprises) with the intent to help enterprises view consumers, institutions and their organisation as one interweaved entity. Needs theories are known to be crucial behind much of the understanding of human behaviour and in particular in the workplace and by the consumer. This paper examines the development of hierarchical needs theory from Maslow to Gough with the intent to better identify consumer needs, provide examples of current and past business opportunities and macroscopically show the progression from red to blue ocean strategies . The authors provide an overview of needs theories seeded through motivational theory also with the aim to uncover the differences in having (sometimes known as deficit needs) and being needs (sometimes known as growth needs) and then subsequently link them to enterprise strategies, improved consumer understanding and better market exploitation.Maslow, Herzberg, Needs, Motivation, Having, Being, Uniformity. Diversity, Part A
Mathematical modeling of water management strategies in urbanizing river basins
No full textSubmitted to Office of Water Resources Research, United States Department of the Interior.AER72-72WRW-GVS25.OWRR Project no. B-071-COLO
- …
