How to Mix Molecules with Mathematics

In this paper we develop two methods to calculate thermodynamic properties of mixtures. Starting point are the basic assumptions that also form the basis for the COSMO-RS model. In this approach, the individual molecules are represented by their geometrical shape with an electrical charge density on their surfaces. Next, the surface is split up into surface segments each with its own charge. In COSMO-RS a strong reduction is introduced by treating the segments as if they are completely independent. In the present study we take into account that the coupling between two patches is essentially dependent on the charge distribution on neighboring segments and on the local geometrical structure of the surface. Two approaches are followed. The first one points out how the model equations, which comprise the optimization of the entropy and conservation of internal energy, can efficiently be solved in general, thus also if the dependency between segments and the local geometry is included in the expression for the coupling energy between segments. In the second method the configuration with maximal entropy and prescribed energy is sought via simulation. Successive molecular configurations of the mixture are simulated and updated via a genetic algorithm to optimize the entropy. The second method is more time consuming but very general

A new characterization of Baire class 1 functions

We give a new characterization of the Baire class 1 functions (defined on an ultrametric space) by proving that they are exactly the pointwise limits of sequences of full functions (which are particularly simple Lipschitz functions). Moreover we highlight the link between the two classical stratifications of the Borel functions by showing that the Baire class functions of some level are exactly those obtained as uniform limits of sequences of Delta functions (of a corresponding level).Comment: 16 pages; corrected typos and affiliatio

Call the celebrity: Voicing the experience of women and ageing through the distinctive vocal presence of Vanessa Redgrave

Within the field of ageing studies, ageism is being challenged by querying the ‘progress-versus-decline’ binary (Gullette, 2004) so common in film and television texts and by interrogating the predominant discourse of age, which ‘pivots on the blunt binary of young and old, as if there were only two states of age’ (Woodward, 1999, p. xvii). One of the more productive perspectives suggests that we are young and old or old and young at the same time (Moglen, 2008; Segal, 2013). Whilst contemporary screen media now presents images of ageing which are more diverse and complex than earlier stereotypes and images, the oppositional binary between old and young still remains the most prevalent mode of representing generations. In this article, we focus on the contribution of Vanessa Redgrave’s distinctive vocal presence in relation to the narration of age. As the ‘grande dame who won't conform’, the distinctiveness of Redgrave’s voice incorporates elements of her controversial celebrity persona such as her profound belief in social justice and her personal experience of loss and mourning. Her own physiological ageing is also manifest in the sonic cadences of her post-menopausal voice but her status as one of Britain’s greatest and most enduring actresses works against typical notions of the disempowered older voice to command attention through her skilled delivery of vocal frequency, intensity range and quality (Prakup, 2012). As the voice-over narrator in Call the Midwife (BBC, 2012 – ) Redgrave’s voice facilitates a rare example of female subjectivity emerging as young and old at the same time. Redgrave’s serene, measured voice suggests both a process of reliable narration and also identity integration along the life course. Her voice-over serves to link the past and present of one of the central characters (Jenny Lee). The younger Jenny is thus mediated by an older woman’s experiences and, at the same time, the late life narrative of the older Jenny is re-energized

Call the celebrity: Voicing the experience of women and ageing through the distinctive vocal presence of Vanessa Redgrave

Within the field of ageing studies, ageism is being challenged by querying the ‘progress-versus-decline’ binary (Gullette, 2004) so common in film and television texts and by interrogating the predominant discourse of age, which ‘pivots on the blunt binary of young and old, as if there were only two states of age’ (Woodward, 1999, p. xvii). One of the more productive perspectives suggests that we are young and old or old and young at the same time (Moglen, 2008; Segal, 2013). Whilst contemporary screen media now presents images of ageing which are more diverse and complex than earlier stereotypes and images, the oppositional binary between old and young still remains the most prevalent mode of representing generations. In this article, we focus on the contribution of Vanessa Redgrave’s distinctive vocal presence in relation to the narration of age. As the ‘grande dame who won't conform’, the distinctiveness of Redgrave’s voice incorporates elements of her controversial celebrity persona such as her profound belief in social justice and her personal experience of loss and mourning. Her own physiological ageing is also manifest in the sonic cadences of her post-menopausal voice but her status as one of Britain’s greatest and most enduring actresses works against typical notions of the disempowered older voice to command attention through her skilled delivery of vocal frequency, intensity range and quality (Prakup, 2012). As the voice-over narrator in Call the Midwife (BBC, 2012 – ) Redgrave’s voice facilitates a rare example of female subjectivity emerging as young and old at the same time. Redgrave’s serene, measured voice suggests both a process of reliable narration and also identity integration along the life course. Her voice-over serves to link the past and present of one of the central characters (Jenny Lee). The younger Jenny is thus mediated by an older woman’s experiences and, at the same time, the late life narrative of the older Jenny is re-energized

Effects of noise on hysteresis and resonance width in graphene and nanotubes resonators

We investigate the role that noise plays in the hysteretic dynamics of a suspended nanotube or a graphene sheet subject to an oscillating force. We find that not only the size but also the position of the hysteresis region in these systems can be controlled by noise. We also find that nano-resonators act as noise rectifiers: by increasing the noise in the setup, the resonance width of the characteristic peak in these systems is reduced and, as a result, the quality factor is increased.Comment: 15 pages, 6 figures. Sent to PRB (in revision

Searching for low mass objects around nearby dMe radio stars

Nearby M-dwarfs are best suited for searches of low mass companions. VLBI phase-referencing observations with sensitive telescopes are able to detect radio star flux-densities of tenths of mJy as well as to position the star on the sky with submilliarcsecond precision. We have initiated a long-term observational program, using EVN telescopes in combination with NASA DSN dishes, to revisit the kinematics of nearby, single M dwarfs. The precision of the astrometry allows us to search for possible companions with masses down to 1 Jupiter mass. In this contribution we report preliminary results of the first observation epochs, in which we could detect some of the radio stars included in our program.Comment: Proceedings of the 6th European VLBI Network Symposium, Ros E., Porcas R.W., Lobanov A.P., & Zensus J.A. (eds.), MPIfR, Bonn, Germany, p. 255-258 (2002). 4 pages, 3 figures, needs evn2002.cl