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,

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

Predicting space climate change

The recent decline in the open magnetic flux of the Sun heralds the end of the Grand Solar Maximum (GSM) that has persisted throughout the space age, during which the largest‐fluence Solar Energetic Particle (SEP) events have been rare and Galactic Cosmic Ray (GCR) fluxes have been relatively low. In the absence of a predictive model of the solar dynamo, we here make analogue forecasts by studying past variations of solar activity in order to evaluate how long‐term change in space climate may influence the hazardous energetic particle environment of the Earth in the future. We predict the probable future variations in GCR flux, near‐Earth interplanetary magnetic field (IMF), sunspot number, and the probability of large SEP events, all deduced from cosmogenic isotope abundance changes following 24 GSMs in a 9300‐year record

XMM-Newton reveals ~100 new LMXBs in M31 from variability studies

We have conducted a survey of X-ray sources in XMM-Newton observations of M31, examining their power density spectra (PDS) and spectral energy distributions (SEDs). Our automated source detection yielded 535 good X-ray sources; to date, we have studied 225 of them. In particular, we examined the PDS because low mass X-ray binaries (LMXBs) exhibit two distinctive types of PDS. At low accretion rates, the PDS is characterised by a broken power law, with the spectral index changing from ~0 to ~1 at some frequency in the range \~0.01--1 Hz; we refer to such PDS as Type A. At higher accretion rates, the PDS is described by a simple power law; we call these PDS Type B. Of the 225 sources studied to date, 75 exhibit Type A variability, and are almost certainly LMXBs, while 6 show Type B but not Type A, and are likely LMXBs. Of these 81 candidate LMXBs, 71 are newly identified in this survey; furthermore, they are mostly found near the centre of M31. Furthermore, most of the X-ray population in the disc are associated with the spiral arms, making them likely high mass X-ray binaries (HMXBs). In general these HMXBs do not exhibit Type A variability, while many central X-ray sources (LMXBs) in the same luminosity range do. Hence the PDS may distinguish between LMXBs and HMXBs in this luminosity range.Comment: 4 pages, 2 figures. To appear in proceedings of IAUS230: "Populations of High Energy Sources in Galaxies", 14-19 August 2005, Dublin, Eds E.J.A. Meurs and G. Fabbian

Ion charge states and potential geoeffectiveness: the role of coronal spectroscopy for space-weather forecasting

Severe space-weather is driven by interplanetary coronal mass ejections (ICMEs), episodic eruptions of solar plasma and magnetic flux that travel out through the heliosphere and can perturb the Earth’s magnetosphere, ionosphere and upper atmosphere. In order for space-weather forecasts to allow effective mitigating action, forecasts must be made as early as possible, necessitating identification of potentially “geoeffective” ICMEs close to the Sun. This presents two challenges. Firstly, geoeffectiveness is primarily determined by the magnetic field intensity and orientation, both of which are difficult to measure close to the Sun. Secondly, the magnetic field evolves in transit between the Sun and the Earth, sometimes in a highly non-linear way. Conversely, solar wind ion charge states, such as the ratio of O7+ to O6+, can be observed near the Sun through coronal spectroscopy and are fixed by the electron temperature at the coronal height where ion-electron collisions are last possible as the ICME erupts. After this point, they are said to be “frozen in” as they do not evolve further as the ICME propagates through the solar wind. In this study we show that ions charge states, while not geoeffective in and of themselves, act as strong markers for the geoeffectiveness of the ICME. The probability of severe space weather is around seven times higher in “hot” ICMEs than “cold” ICMEs, as defined by O7+/O6+. We suggest that coronal spectroscopy of ICMEs could complement current forecasting techniques, providing valuable additional information about potential geoeffectiveness

The seminal legacy of the Southern African Bird Atlas Project

The first Southern African Bird Atlas Project was launched in 1986 and gathered bird distribution data from six countries of southern Africa. The project culminated with the publication of The Atlas of Southern African Birds in 1997. The database generated by the project, seven million bird distribution records, has been widely used by four groups: environmental consultants (for example, to locate electricity transmission lines), conservationists (planning conservation strategies), research scientists (especially macro-ecologists and biogeographers) and birders (ecotourism materials). By 2007, the database had spawned 50 research publications and eight Ph.D.s and master's degrees. These products are a tribute to the more than 5000 'citizen scientists', who gathered the bulk of the data. The atlas concept has been extended to frogs, reptiles, spiders and butterflies; a second bird atlas started in 2007 and will, for example, facilitate knowledge of the impact of environmental change on birds. The South African National Biodiversity Institute is playing a lead role in initiating these new projects

Interplay of Peltier and Seebeck effects in nanoscale nonlocal spin valves

We have experimentally studied the role of thermoelectric effects in nanoscale nonlocal spin valve devices. A finite element thermoelectric model is developed to calculate the generated Seebeck voltages due to Peltier and Joule heating in the devices. By measuring the first, second and third harmonic voltage response non locally, the model is experimentally examined. The results indicate that the combination of Peltier and Seebeck effects contributes significantly to the nonlocal baseline resistance. Moreover, we found that the second and third harmonic response signals can be attributed to Joule heating and temperature dependencies of both Seebeck coefficient and resistivity.Comment: 4 pages, 4 figure