The strong Malthusian behavior of growth-fragmentation processes

Growth-fragmentation processes describe the evolution of systems of cells which grow continuously and fragment suddenly; they are used in models of cell division and protein polymerisation. Typically, we may expect that in the long run, the concentrations of cells with given masses increase at some exponential rate, and that, after compensating for this, they arrive at an asymptotic profile. Up to now, this question has mainly been studied for the average behavior of the system, often by means of a natural partial integro-differential equation and the associated spectral theory. However, the behavior of the system as a whole, rather than only its average, is more delicate. In this work, we show that a criterion found by one of the authors for exponential ergodicity on average is actually sufficient to deduce stronger results about the convergence of the entire collection of cells to a certain asymptotic profile, and we find some improved explicit conditions for this to occur

Probability tilting of compensated fragmentations

Fragmentation processes are part of a broad class of models describing the evolution of a system of particles which split apart at random. These models are widely used in biology, materials science and nuclear physics, and their asymptotic behaviour at large times is interesting both mathematically and practically. The spine decomposition is a key tool in its study. In this work, we consider the class of compensated fragmentations, or homogeneous growth-fragmentations, recently defined by Bertoin. We give a complete spine decomposition of these processes in terms of a L\'evy process with immigration, and apply our result to study the asymptotic properties of the derivative martingale.Comment: 41 pages, 1 figure. This revised version improves the conditions in Theorem 6.

Probabilistic aspects of critical growth-fragmentation equations

The self-similar growth-fragmentation equation describes the evolution of a medium in which particles grow and divide as time proceeds, with the growth and splitting of each particle depending only upon its size. The critical case of the equation, in which the growth and division rates balance one another, was considered by Doumic and Escobedo in the homogeneous case where the rates do not depend on the particle size. Here, we study the general self-similar case, using a probabilistic approach based on L\'evy processes and positive self-similar Markov processes which also permits us to analyse quite general splitting rates. Whereas existence and uniqueness of the solution are rather easy to establish in the homogeneous case, the equation in the non-homogeneous case has some surprising features. In particular, using the fact that certain self-similar Markov processes can enter $(0,\infty)$ continuously from either $0$ or $\infty$, we exhibit unexpected spontaneous generation of mass in the solutions.Comment: 28 pages. v2 adds an expository section 6 and fixes some error

The Impact of Experiential Augmented Reality Applications on Fashion Purchase Intention

Utilizing the stimulus-organism-response (SOR) model, the purpose of this study is to examine the effects of augmented reality (AR) (specifically augmentation) on consumers’ affective and behavioral response and to assess whether consumers’ hedonic motivation for shopping moderates this relationship. An experiment using the manipulation of AR and no AR was conducted with 162 participants aged between 18 and 35. Participants were recruited through snowball sampling and randomly assigned to the control or stimulus group. The hypothesized associations were analyzed using linear regression with bootstrapping. The paper demonstrates the benefit of using an experiential AR retail application (app) to positively impact purchase intention. The results show this effect is mediated by positive affective response. Furthermore, hedonic shopping motivation moderates the relationship between augmentation and the positive affective response. Because of the chosen research approach, the results may lack generalizability to other forms of augmentation. Therefore, researchers are encouraged to test the proposed model using different types of AR stimuli. Furthermore, replication of the study with other populations would increase the generalizability of the findings. Results of this study provide a valuable reference for retailers of the benefits of using AR when attempting to optimize experiential value in online environments. The study contributes to experiential retail and consumer purchase behavior research by deepening the conceptualization of the impact of experiential technologies, more specifically AR apps, by considering the role of hedonic shopping motivations.Peer reviewe

Roche tomography of cataclysmic variables - V. A high-latitude star-spot on RU Pegasi

We present Roche tomograms of the secondary star in the dwarf nova system RU Pegasi derived from blue and red arm ISIS data taken on the 4.2-m William Herschel Telescope. We have applied the entropy landscape technique to determine the system parameters and obtained component masses of M1 = 1.06 Msun, M2 = 0.96 Msun, an orbital inclination angle of i = 43 degrees, and an optimal systemic velocity of gamma = 7 km/s. These are in good agreement with previously published values. Our Roche tomograms of the secondary star show prominent irradiation of the inner Lagrangian point due to illumination by the disc and/or bright spot, which may have been enhanced as RU Peg was in outburst at the time of our observations.We find that this irradiation pattern is axi-symmetric and confined to regions of the star which have a direct view of the accretion regions. This is in contrast to previous attempts to map RU Peg which suggested that the irradiation pattern was non-symmetric and extended beyond the terminator. We also detect additional inhomogeneities in the surface distribution of stellar atomic absorption that we ascribe to the presence of a large star-spot. This spot is centred at a latitude of about 82 degrees and covers approximately 4 per cent of the total surface area of the secondary. In keeping with the high latitude spots mapped on the cataclysmic variables AE Aqr and BV Cen, the spot on RU Peg also appears slightly shifted towards the trailing hemisphere of the star. Finally, we speculate that early mapping attempts which indicated non-symmetric irradiation patterns which extended beyond the terminator of CV donors could possibly be explained by a superposition of symmetric heating and a large spot.Comment: 14 pages, 10 figures, 3 tables Accepted for publication in Monthly Notices of the Royal Astronomical Societ

The effects of distraction on threat-related changes in attention focus and postural control

The purpose of this thesis was to investigate whether threat-related changes in attention focus and postural control could be modified using distraction. Healthy young adults (N=21) stood without (No Threat) and with (Threat) the possibility of receiving an unpredictable anterior or posterior support surface translation under conditions in which they were required to perform or not perform a distractor task. The results of the thesis showed significant threat-related changes in attention focus and postural control independent of distraction. When performing with distraction compared to without, threat-related changes in high-frequency sway (1.0-2.5 Hz) were significantly reduced, and threat-related changes in attention focus to self-regulatory strategies tended to be reduced. These findings suggest that distraction may modify threat-related changes in attention focus and postural control

Managing an 'Army of Peoples': Identity, Command and Performance in the Habsburg Officer Corps, 1914-1918

This article examines the officers who led the Habsburg Army during the First World War. It highlights the complexity of their identities, demonstrating that this went well beyond the a-national – nationalist dichotomy in much historiography. It also argues that these officers’ identities had a profound impact on how their army functioned in the field. The article first studies the senior command in 1914–16, showing how its wartime learning processes were shaped by transnational attitudes. These officers had belonged in peace to an international military professional network. When disaster befell their army at the outset of the First World War, it was natural for them to seek lessons from foreign armies, at first from their major enemies, the Russians, and later their German allies. The second half of the article explores the changing loyalties of the reserve officers tasked with frontline command in the later war years. It contends that the officer corps’ focus on maintaining social and educational standards resulted in an influx of middle-class junior leaders whose conditional commitment to the Empire and limited language skills greatly influenced the Habsburg Army’s record of longevity but mediocre combat performance