Affordances in activity theory and cognitive systems engineering

For the last decade, the Gibsonian concept of affordances has at- tracted much attention within Human-Machine Interaction (HMI) and related research communities. The application of Gibson's ideas in HMI has lead to the notion of direct manipulation of interface objects. Previously, the focus has been on design for low level interaction modalities. To incorporate the concept of affordances in the design of human computer interaction it is necessary to systematically unravel affordances that support human action possibilities. Furthermore, it is a necessity that Gibson's theory of affordances is supplemented by careful analyses of other human modalities and activities than visual perception. Within HMI two well established perspectives on HMI, Activity Theory (AT) and Cognitive Systems Engineering (CSE), have discussed such analyses and design of action possibilities focusing on providing computer support for work situations. Within these perspectives, the primary unit of analysis in HMI is human work activity and the socio-cultural context in which this activity is carried out. Thus, they emphasise the actors' purposeful activity as the most important design rationale. According to previous views in HMI, notably those that have been put forward by Norman and Gaver, affordances are in the foreground, whereas the system or work area is in the background. AT and CSE share the view that the actors' perception of foreground and background shifts dynamically according to the actors' situational context in purposeful activity. AT and CSE follow the original notion by Gibson on the actor's dynamic shifting between foreground and background of the environment. Furthermore, their work- and actor-centred approach to analysis and design of information sys..

After interaction

Interaction turns on the outmoded idea that there is a natural separation between people and things. Technologies have always been about producing dense, interconnected relationships of humans and non-humans. Seeing design as performing expansive networks of relations opens up possibilities beyond the human-computer interactions. The relations go much deeper than any discrete interactions between user and machine. Extensive investigations have also demonstrated how cognitive capacities can extend beyond the individual's mind and into the interactions between people

Optimization of Preanalytical Variables for cfDNA Processing and Detection of ctDNA in Archival Plasma Samples

DNA released from cells into the peripheral blood is known as cell-free DNA (cfDNA), representing a promising noninvasive source of biomarkers that could be utilized to manage Diffuse Large B-Cell Lymphoma (DLBCL), among other diseases. The procedure for purification and handling of cfDNA is not yet standardized, and various preanalytical variables may affect the yield and analysis of cfDNA, including the purification kits, blood collection tubes, and centrifugation regime. Therefore, we aimed to investigate the impact of these preanalytical variables on the yield of cfDNA by comparing three different purification kits DNeasy Blood & Tissue Kit (Qiagen), QIAamp Circulating Nucleic Acid Kit (Qiagen), and Quick-cfDNA Serum & Plasma Kit (Zymo Research). Two blood collection tubes (BCTs), EDTA-K2 and Cell-Free DNA (Streck), stored at four different time points before plasma was separated and cfDNA purified, were compared, and for EDTA tubes, two centrifugation regimes at 2000 × g and 3000 × g were tested. Additionally, we have tested the utility of long-term archival blood samples from DLBCL patients to detect circulating tumor DNA (ctDNA). We observed a higher cfDNA yield using the QIAamp Circulating Nucleic Acid Kit (Qiagen) purification kit, as well as a higher cfDNA yield when blood samples were collected in EDTA BCTs, with a centrifuge regime at 2000 × g. Moreover, ctDNA detection was feasible from archival plasma samples with a median storage time of nine years

Towards reusable personas for everyday design

Personas are artificial character based representations of user goals, attitudes, motivations and abilities which enable designers to focus their design efforts on key, targeted users. The success of personas in design is due to their capacity to enable designers to empathize with users and understand user goals. Persona development is rooted in the rigorous collection and analysis of data specifically related to the design project being undertaken. New design projects thus require the development of new personas. Since redevelopment is not always achievable attention has turned towards reuse of personas and the underlying data. This paper reports on ongoing research into the development of reusable personas for use by non-expert, everyday designers. Such designers are regularly faced with small scale but diverse design challenges for which they cannot carry out user research and modelling. They can, however, make use of general, reusable personas developed independently of their current design project

Painting the ideal home: using art to express visions of technologically supported independent living for older people in North East England

This paper describes the investigation of the development of future technological products to support older people in everyday living through the agency of a community art group. Recent research has identified a number of challenges facing designers seeking to use traditional participatory design approaches to gather technology requirements data from older people. Here, a project is described that sought to get a group of older people to think creatively about their needs and desires for technological support through the medium of paint. The artistic expression technique described in this article allowed the identification of issues that had also been found by previous research that used a range of different techniques. This indicates that the approach shows promise, as it allows information to be gathered in an environment that is comfortable and familiar using methods already known by the participants and which they find enjoyable. It provides a complement (or possible alternative) to standard protocols and has the potential benefit of extracting even richer information as the primary task for participants is enjoyable in its own right and is not associated with an interrogative process. Furthermore, it is argued that some of the key risks of traditional approaches are lessened or removed by the naturalistic setting of this approach

Population genomics of an outbreak of the potato late blight pathogen, <i>Phytophthora infestans</i>, reveals both clonality and high genotypic diversity

An outbreak of the potato late blight pathogen Phytophthora infestans in Denmark was characterized in order to resolve the population structure and determine to what extent sexual reproduction was occurring. A standard set of microsatellite simple sequence repeats (SSRs) and single nucleotide polymorphism (SNP) markers generated using restriction site‐associated DNA sequencing (RAD‐seq) were employed in parallel. A total of 83 individuals, isolated from seven different potato fields in 2014, were analysed together with five Danish whole‐genome sequenced isolates, as well as two Mexican individuals used as an outgroup. From a filtered dataset of 55 288 SNPs, population genomics analyses revealed no sign of recombination, implying clonality. In spite of this, multilocus genotypes were unique to individual potato fields, with little evidence of gene flow between fields. Ploidy analysis performed on the SNPs dataset indicated that the majority of isolates were diploid. These contradictory results with clonality and high genotypic diversity may suggest that rare sexual events likely still contribute to the population. Comparison of the results generated by SSRs vs SNPs data indicated that large marker sets, generated by RAD‐seq, may be advised going forward, as it provides a higher level of genetic discrimination than SSRs

An isotopic analysis of ionising radiation as a source of sulphuric acid

Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO&lt;sub&gt;2&lt;/sub&gt; through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in &lt;sup&gt;34&lt;/sup&gt;S and we find an enrichment factor (&amp;delta;&lt;sup&gt;34&lt;/sup&gt;S) of 8.7 ± 0.4&amp;permil; (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of &lt;sup&gt;33&lt;/sup&gt;S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO&lt;sub&gt;2&lt;/sub&gt; by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion