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

Modeling the iron oxides and oxyhydroxides for the prediction of environmentally sensitive phase transformations

Iron oxides and oxyhydroxides are challenging to model computationally as competing phases may differ in formation energies by only several kJ/mol, they undergo magnetization transitions with temperature, their structures may contain partially occupied sites or long-range ordering of vacancies, and some loose structures require proper description of weak interactions such as hydrogen bonding and dispersive forces. If structures and transformations are to be reliably predicted under different chemical conditions, each of these challenges must be overcome simultaneously, while preserving a high level of numerical accuracy and physical sophistication. Here we present comparative studies of structure, magnetization, and elasticity properties of iron oxides and oxyhydroxides using density functional theory calculations with plane-wave and locally-confined-atomic-orbital basis sets, which are implemented in VASP and SIESTA packages, respectively. We have selected hematite, maghemite, goethite, lepidocrocite, and magnetite as model systems from a total of 13 known iron oxides and oxyhydroxides; and use same convergence criteria and almost equivalent settings in order to make consistent comparisons. Our results show both basis sets can reproduce the energetic stability and magnetic ordering, and are in agreement with experimental observations. There are advantages to choosing one basis set over the other, depending on the intended focus. In our case, we find the method using PW basis set most appropriate, and combine our results to construct the first phase diagram of iron oxides and oxyhydroxides in the space of competing chemical potentials, generated entirely from first principlesComment: 46 pages - Accepted for publication in PRB (19 journal pages), January 201

The solar influence on the probability of relatively cold UK winters in the future

Recent research has suggested that relatively cold UK winters are more common when solar activity is low (Lockwood et al 2010 Environ. Res. Lett. 5 024001). Solar activity during the current sunspot minimum has fallen to levels unknown since the start of the 20th century (Lockwood 2010 Proc. R. Soc. A 466 303–29) and records of past solar variations inferred from cosmogenic isotopes (Abreu et al 2008 Geophys. Res. Lett. 35 L20109) and geomagnetic activity data (Lockwood et al 2009 Astrophys. J. 700 937–44) suggest that the current grand solar maximum is coming to an end and hence that solar activity can be expected to continue to decline. Combining cosmogenic isotope data with the long record of temperatures measured in central England, we estimate how solar change could influence the probability in the future of further UK winters that are cold, relative to the hemispheric mean temperature, if all other factors remain constant. Global warming is taken into account only through the detrending using mean hemispheric temperatures. We show that some predictive skill may be obtained by including the solar effect

Fungal dissemination by housefly (Musca domestica L.) and contamination of food commodities in rural areas of South Africa

Abstract: Several insects that act as vectors, including houseflies (Musca domestica L.), are often considered to be an important source of fungal contamination in human foods.Houseflies are also involved in the transmission of bacterial pathogens that may pose a serious hazard to human health. Thus, the rural population of South Africa, as typified by that in the Gauteng Province investigated in this study, is at high risk from fungal exposure disseminated by houseflies and it is therefore important to assess the role of flies in contaminating various food commodities. Eighty four samples of houseflies (captured fromhouseholds and pit toilets)were studied for their potential to carry fungal spores into food commodities. The fungi occurring in samples of rawmaize (15) and porridge (19)were also assessed. Fungal isolates were identified based on morphological characteristics by conventional identification methods. Fifteen genera of fungi were isolated and identified, of which Aspergillus, Fusarium, Penicillium, Cladosporium, Moniliella and Mucor were the most prevalent in all three sample types analysed. The incidence rates of fungal contamination per total fungal count isolated in houseflies, maize and porridge were recorded with mean fungal load of 2 × 108 CFU/ml, 1 × 107 CFU/g and 2 × 107 CFU/g respectively. Additionally, A. flavus, A. parasiticus, F. verticillioides, F. proliferatum, P. verrucosum, P. aurantiogriseum and M. suaveolens were the most frequent fungal isolates in houseflies with incidence rate of 34%, 11%, 27%, 21%, 22%, 17% and 32% respectively. F. verticillioides, A. flavus, A. niger and P. oslonii were the most prevalent species contaminating porridge and maize with incidence rate of 23%, 32%, 16% and 28% in maize samples,while incidence rates of 59%, 15% and 29% were recorded in porridge samples with the exception of F. verticillioides. The prevalence of these genera of fungi may pose serious health risks

Detection of amoeba-associated Legionella pneumophila in hospital water networks of Johannesburg

Abstract: The prevalence of free-living amoeba and associated Legionella spp. in hospital water systems may pose a risk of Legionnaires’ disease to immuno-compromised patients. This study investigated the occurrence of amoeba-associated Legionella pneumophila in three South African hospital water systems. A total of 98 water and/or biofilm samples were collected from the sterilisation unit, theatres, neonatal ward and intensive care units. Amoebae were isolated from 71 (72.4%) samples. Isolated amoebae were analysed using qPCR and culture methods to test for the presence of Legionella. L. pneumophila did not grow on selective media in any of the samples. A total of 7 out of the 71 (9.9%) amoeba-positive samples showed a positive reaction for L. pneumophila using qPCR. Although relatively few samples were positive for Legionella in this preliminary study, the association with amoeba still presents a potential public health risk to immuno-compromised patients when exposed to contaminated water

Aborsie: ’n Juridiese, etiese en regsetiese vraagstuk

In die geledere van skokkende en onetiese dade in die menslike samelewing, beklee aborsie ’n besondere plek. Vir wetenskaplike doeleindes kan aborsie oor die algemeen gedefinieer word as die skeiding van of afdrywing uit die moederlyf van die „produk” van konsepsie, synde ’n fetus (Geldenhuys, 1974:11; O’Donovan 1975:2). ’n Verdere element van die definisie, wat die blote afdrywing van die vrug gewoonlik kwalifiseer, is dat die fetus, met betrekking tot nageboortelike lewe gesproke, nie lewensvatbaar moes gewees het nie. Met die byvoeging van hierdie element tot die eie definisie word tans egter vertoef ten einde eers die belangrike vraag wanneer lewe ontstaan, te beantwoord

Submerged in the mainstream? A case study of an immigrant learner in a New Zealand primary classroom

Immigrant children from diverse language backgrounds face not only linguistic challenges when enrolled in mainstream English-medium classrooms, but also difficulties adjusting to an unfamiliar learning community. The culture of primary school classrooms in New Zealand typically reflects conventions across three dimensions: interactional, instructional task performance and cognitive-academic development. All three dimensions are underpinned by the culturally specific discourse conventions involved in language socialisation. New learners may be helped by classmates or their teacher to understand and successfully use these conventions, but left on their own they may sink rather than swim. This is a case study of one Taiwanese 11-year old boy, 'John', who entered a New Zealand primary classroom midway through the school year. John's basic conversational ability was sound, but he did not possess the interactive classroom skills needed to operate in the new culture of learning. Selected from a wider study of the classroom, transcript data from audio-recorded excerpts of John's interactions over several months with his teacher and classmates are interpreted from perspectives derived from sociocultural and language socialisation theories. The article concludes with a brief consideration of the extent to which John constructed, or was constrained from constructing meaningful learning experiences, and suggestions for further research and reflection

Observational detection of eclipses of J5 Amalthea by the Galilean satellites

We carried out observations of the small jovian satellite Amalthea (J5) as it was being eclipsed by the Galilean satellites near the 2009 equinox of Jupiter in order to apply the technique of mutual event photometry to the astrometric determination of this satellite's position. The observations were carried out during the period 06/2009-09/2009 from the island of Maui, Hawaii and Siding Spring, Australia with the 2m Faulkes Telescopes North and South respectively. We observed in the near-infrared part of the spectrum using a PanStarrs-Z filter with Jupiter near the edge of the field in order to mitigate against the glare from the planet. Frames were acquired at rates >1/min during eclipse times predicted using recent JPL ephemerides for the satellites. Following subtraction of the sky background from these frames, differential aperture photometry was carried out on Amalthea and a nearby field star. We have obtained three lightcurves which show a clear drop in the flux from Amalthea, indicating that an eclipse took place as predicted. These were model-fitted to yield best estimates of the time of maximum flux drop and the impact parameter. These are consistent with Amalthea's ephemeris but indicate that Amalthea is slightly ahead of, and closer to Jupiter than, its predicted position by approximately half the ephemeris uncertainty in these directions. We argue that a ground-based campaign of higher-cadence photometry accurate at the 5% level or better during the next season of eclipses in 2014-15 should yield positions to within 0".5 and affect a corresponding improvement in Amalthea's ephemeris.Comment: Published in A&A in 2010; 6 pages, 2 figures, 3 table