Chemi-ionization in Solar Photosphere: Influence on the Hydrogen Atom excited States Population

In this paper, the influence of chemi-ionization processes in $H^*(n \ge 2) + H(1s)$ collisions, as well as the influence of inverse chemi-recombination processes on hydrogen atom excited-state populations in solar photosphere, are compared with the influence of concurrent electron-atom and electron-ion ionization and recombination processes. It has been found that the considered chemi-ionization/recombination processes dominate over the relevant concurrent processes in almost the whole solar photosphere. Thus, it is shown that these processes and their importance for the non-LTE modeling of the solar atmosphere should be investigated further

Electrical conductivity of plasmas of DB white dwarf atmospheres

The static electrical conductivity of non-ideal, dense, partially ionized helium plasma was calculated over a wide range of plasma parameters: temperatures $1\cdot 10^{4}\textrm{K} \lesssim T \lesssim 1\cdot 10^{5}\textrm{K}$ and mass density $1 \times 10^{-6} \textrm{g}/\textrm{cm}^{3} \lesssim \rho \lesssim 2 \textrm{g}/\textrm{cm}^{3}$. Calculations of electrical conductivity of plasma for the considered range of plasma parameters are of interest for DB white dwarf atmospheres with effective temperatures $1\cdot 10^{4}\textrm{K} \lesssim T_{eff} \lesssim 3\cdot 10^{4}\textrm{K}$. Electrical conductivity of plasma was calculated by using the modified random phase approximation and semiclassical method, adapted for the case of dense, partially ionized plasma. The results were compared with the unique existing experimental data, including the results related to the region of dense plasmas. In spite of low accuracy of the experimental data, the existing agreement with them indicates that results obtained in this paper are correct

The effect of dyadic interactions on learning rotate gesture for technology-naïve older adults

Older adults having limited experience with modern computing technology may find it difficult to learn touch gestures, especially the more complex rotate gesture. Social interactions, as implied by social constructivism, are assumed to be powerful in enabling older adults to acquire the skill of touch gestures. The social effect can be reinforced with the motivational effect of digital games. To verify the assumption, we conducted empirical studies with 59 older adults, who were divided into two groups: 17 Singles and 21 Dyads. They were asked to play a set of digital games on a multi-touch tabletop. Results show that on average Dyads have spent significantly longer time in the games and have performed a significantly higher number of correct rotate gestures than Singles. Future work focuses on analyzing the emotional aspect of social interactions and identifying further applications of social gaming to other ageing issue

Issues faced by vision-impaired users of interactive TV search facilities

This paper reports two studies of digital television users. The first study investigates the behaviour of non-impaired users to understand typical usage patterns and problem-solving, attempting three representative tasks using a digital television terrestrial receiver. Videos were analysed to identify problem incidents and attempts at recovery. Patterns observed included misidentifying handset menu options leading to extended guessed action, repeated misspecification of task and repeated re-performance to confirm actions. The results show that interaction with Digital TV in its current handset-based form involves considerable reactive action specification and corrective action, suggesting that interaction endemically difficult for those with various levels of low vision. The second study, a less formal probe of users with visual impairments, suggests that even users with relatively mild visual impairments may struggle with current two-device interaction. However, suitable strategies for supporting vision impaired users may as much to do with user preferences rather than simply accessibility. We conclude by discussing the efficacy of current two-device interaction support and possible future directions

The ion-atom absorption processes as one of the factors of the influence on the sunspot opacity

As a continuation of the previous investigations of the symmetric and strongly non-symmetric ion-atom absorption processes in the far UV region within the models of the quiet Sun photosphere, these processes are studied here within a model of the sunspot. Here we mean the absorption processes in the H$(1s)$+H$^{+}$ and H$(1s)+X^{+}$ collisions and the processes of the photo-dissociation of the H$_{2}^{+}$ and H$X^{+}$ molecular ions, where $X$ is one of the metal atoms: $X=$Na, Ca, Mg, Si and Al. Obtained results show that the influence of the considered ion-atom absorption processes on the opacity of sunspots in the considered spectral region (110 nm $\lesssim \lambda \lesssim$ 230 nm) is not less and in some parts even larger than the influence of the referent electron-atom processes. In such a way, it is shown that the considered ion-atom absorption processes should be included \emph{ab initio} in the corresponding models of sunspots of solar-type and near solar-type stars. Apart of that, the spectral characteristics of the considered non-symmetric ion-atom absorption processes (including here the case $X$ = Li), which can be used in some further applications, have been determined and presented within this work.Comment: Accepted in Monthly Notices of the Royal Astronomical Societ