A Multi-coloured survey of NGC 253 with XMM-Newton

There is a large body of work that has used the excellent Chandra observations of nearby galaxies with neglible low mass X-ray binary (LMXB) populations. This has culminated in a ``Universal'' X-ray luminosity function (XLF) for high mass X-ray binaries (HMXBs). However, a number of methods have been used to convert from source intensities to luminosities when creating these XLFs. We have taken advantage of the XMM-Newton observations of the nearby starbursting spiral galaxy NGC 253 to test some of these methods. We find the luminosities derived from these various methods to vary by a factor of $\sim$3. We also find the most influential factor in the conversion from intensity to luminosity to be the absorption. We therefore conclude that a more consistent approach is required for determining the true Universal XLF for HMXBs. Ideally, this would involve individual spectral fitting of each X-ray source. Certainly, the line-of-sight absorption should be determined from the observations rather than assuming Galactic absorption. We find the best approach for obtaining an XLF from low-count data to be the splitting of the X-ray sources into two or more intensity intervals, and obtaining a conversion from intensity to flux for each group from spectral modelling of the summed spectrum of that group.Comment: To appear in the proceedings of "X-rays from Nearby Galaxies", 4-7 Septembeer 2007, 4 page

Kinderidentiteit, ras en seksualiteit in Ons is nie almal so nie en Die reuk van appels

This article discusses the self-narration of two children, Marnus in Mark Behr's Die reuk van appels (translated as The smell of apples, 1993) and Gertie in Jeanne Goosen's Ons is nie almal so nie (1990), translated as We're not all like that (2007). These children integrate stereotypes about race and sexuality to form complex, richer narratives about their role in society. Both Gertie and Marnus take contradictory discourses (Coloureds both inferior to us and human like us) and form richer narratives. Both characters are exposed to an alternative non-racist discourse, but “choose” to stay within the dominant racist discourse because their identity as male and female respectively is bound within it. Marnus' choice involves masculinity, violence and sport, and Gertie as Little Red Riding Hood is metaphorically swallowed by the fox of Christian values about women and sex. Keywords: Afrikaans literature, child identity, Jeanne Goosen, Mark Behr, race, sexuality.Tydskrif vir Letterkunde Vol. 45 (2) 2008: pp. 87-10

Systems, interactions and macrotheory

A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors.” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI

Using a Computer Simulation Game to Teach Agri-Business Management

A computer simulation game is used to teach agri-business management to undergraduate students, agri-business managers, and agricultural lenders. A hypothetical farm supply store is used to teach cash flow budgeting, breakeven analysis, and profitability analysis. Evaluations from both undergraduate students and Extension clientele praise the benefits received from active decision-making, competition, and working as a team to facilitate sharing ideas and experiences

Far out past : Hemingway, manhood, and modernism

This dissertation investigates Ernest Hemingway\u27s authorship as an instance of international modernisms forming as sustained engagements with gender and sexuality. By focusing on four of Hemingway\u27s most experimental texts it shows how a figure of both high and popular modernism sought to occupy a heterogeneous space of cultural queerness vitalized by masculinity, national and ethnic identities, and writing.;The introduction discusses how post-war gender, sexual, and literary discourses reflected period obsessions with authenticity in the face of a rising commodity culture. It also introduces the dissertation\u27s argument that Hemingway\u27s success in becoming a valuable literary property rested on a queer authorial engagement with definitions of American masculinity.;Chapter One traces Hemingway\u27s literary career from the publication of his experimental collection of vignettes in our time in Paris (1924) to the larger New York trade edition which marked his U.S. publishing debut in 1925. The transatlantic and transgressive aspects of Hemingway\u27s times illustrate his authoritative and authorial confounding of a highbrow/lowbrow divide of cultural production and affiliations.;Chapter Two examines The Sun Also Rises as a text deeply divided against itself as the product of Jake Barnes and Hemingway\u27s authorship simultaneously. It considers the complex of conflicted desires, fears, and resentments that constitute Hemingway-cum-Barnes\u27s efforts at rendering and remembering lost manhood in the wake of WWI in ways that raise complicated gender questions involving racialized and sexualized boyhood as a promising yet problematic queer zone.;Chapter Three explores further the sexual funniness of Hemingway\u27s authorship and considers how Death in the Afternoon, his non-fiction treatise on Spanish bullfighting, constitutes a deliberately queer authorial project where Hemingway attempts to move his writing and popular authorial standing in new directions in order to assert and transcend his public identity as a man, an author, and an American.;Chapter Four examines Green Hills of Africa as a political critique of imperialism and manhood that manifests itself through Hemingway writing himself and his shortcomings as a white modern man and hunter as a self-deprecating literary joke. In writing such a joke, however, Hemingway also sought to reaffirm his own uniquely authoritative masculine authorship

The Effects of Conditioned Reinforcers on Extinction When Delivered on Schedules of Extinction

The purpose of the present research was to examine extinction of responding with regard to the rapidity and thoroughness of the process when conditioned reinforcement was available on one of five schedules during extinction. Forty-five mixed-breed pigeons served as subjects with 15 in each of three experiments. Reinforcement training schedules were as follows: Experiment 1, continuous; Experiment 2, fixed ratio 15; Experiment 3, variable-interval one-minute. After training, subjects experienced one of five extinction procedures (here called schedules of extinction) which were as follows: traditional schedule without keylight did not provide conditioned reinforcement; traditional with keylight had the keylight on continuously but withheld other conditioned reinforcement (no schedule, per se, was used); the remaining three schedules (i.e., continuous, fixed ratio 15, and variable-interval one-minute) provided the following four conditioned reinforcers: the sound of the food magazine, the hopper light, the sight of food, and the keylight. Predictions for responding were based on the discrimination hypothesis which states that the more alike training and extinction conditions are, the slower the process of extinction. In order to compare response rates among subjects, a percentage of baseline responding was computed. Four spontaneous recovery tests were conducted to measure the thoroughness of the extinction procedures. Results did not support predictions based on the discrimination hypothesis; that is, subject response rates did not appear to be affected by the similarity of the extinction condition to previous training history. The second finding was that the most rapid and thorough extinction was obtained when the extinction schedule was traditional without keylight. When conditioned reinforcement was available, the continuous extinction schedule produced the most rapid and thorough extinction. The third major finding was that the schedule of unconditioned reinforcement was more predictive of extinction responding than was the conditioned reinforcement schedule during extinction. The last finding was that a subject\u27s pattern of responding was typical of the schedule whether it was on an unconditioned or a conditioned reinforcement schedule. It is suggested that extinction-of-a-human-intervention strategies might be more effective if conditioned reinforcement was identified and controlled

Measurement Issues in Assessing Farm Profitability through Cash Tax Returns

It is widely accepted that net farm income reported on an accrual-adjusted income statement is a more appropriate profitability measure than net farm income reported on Schedule F of the federal tax return, which is prepared using cash basis accounting. However, a common practice among agricultural lenders is to use Schedule F net farm income, which uses the cash basis of accounting, as a proxy for accrual-adjusted net farm income. A study of 1,045 individual Illinois farms’ records from 2002 through 2006 found the median absolute annual percentage difference between a three-year average cash and a three-year average accrual-adjusted net farm incomes is 57 percent for farms of stable size; 43 percent for farms with annual gross revenue increasing at rates of less than 5 percent, 50 percent at rates of 5-10 percent, and 58 percent at rates over 10 percent; and 61 percent for farms with a debt-to-asset ratio greater than 40 percent.Agricultural Finance,