Cosmic rays and molecular clouds

This paper deals with the cosmic-ray penetration into molecular clouds and with the related gamma--ray emission. High energy cosmic rays interact with the dense gas and produce neutral pions which in turn decay into two gamma rays. This makes molecular clouds potential sources of gamma rays, especially if they are located in the vicinity of a powerful accelerator that injects cosmic rays in the interstellar medium. The amplitude and duration in time of the cosmic--ray overdensity around a given source depend on how quickly cosmic rays diffuse in the turbulent galactic magnetic field. For these reasons, gamma-ray observations of molecular clouds can be used both to locate the sources of cosmic rays and to constrain the properties of cosmic-ray diffusion in the Galaxy.Comment: To appear in the proceedings of the San Cugat Forum on Astrophysics 2012, 27 pages, 10 figure

PAUSED for thought? Using verbal protocol analysis to understand the situational and temporal cues in the decision-making of residential burglars

Using verbal protocol analysis (VPA) alongside semi-structured interviews, this research aimed to explicate the situational dynamics that inform the decision-making and target selection of residential burglars. Focusing on the VPA method, novel to criminological research, the paper considers the contribution of this empirical approach for studying the decision-making of offenders in situ. The findings reveal a series of cues, encapsulated in the ‘PAUSED’ model, that are drawn upon by residential burglars to assess the suitability of a target; determining whether it is profitable, accessible, uninterruptible, surveillable, escapable and/or dishonourable. The PAUSED model is unpacked to articulate a collection of visual stimuli that serve to disrupt and suspend the otherwise rapid flow of target appraisal. Discussion of the strengths and limitations of the VPA method, and how it can compliment other approaches to understanding the decision-making of residential burglars, is provided

Comparison Between BlindLogin and Other Graphical Password Authentication Systems

This pilot study was done to evaluate the picture superiority effect on the memorability and usability of BlindLogin based on the Usability-Deployability-Security (UDS) Model and to compare the results with other graphical password authentication systems found in literature. The results from this pilot study indicated that the visually impaired users generally thought that BlindLogin was better than the textual password based on all the UDS Model usability criteria. The results further indicated that BlindLogin was significantly better than textual passwords in four usability criteria (Memorywise Effortless, Infrequent Errors, Efficient to Use and Physically Effortless). For Memorywise-Effortless, BlindLogin (p < 0.012) is more significant than Image PassTiles (p < 0.013) and much more significant than Object PassTiles (p < 0.045). For Infrequent Errors, BlindLogin (p < 0.015) is almost as significant as Passpoints (p < 0.013). The security of BlindLogin was also assessed by tabulating the password space and launching a dictionary attack and a brute-force attack using the capabilities of the cloud. The results showed that it would take about 48188.59 years to brute-force a BlindLogin password using the capabilities of the cloud, which is better than DAS (541.8 years) and Grid Selection (541.8 years). As currently graphical authentication systems designed for the visually impaired have yet to be found in literature, BlindLogin has been shown to be a memorable and usable graphical authentication system for visually impaired users as compared to other graphical password systems which was designed only for sighted users on the mobile platform