Taming the Non Abelian Born-Infeld Action

We show how to reduce the non abelian Born-Infeld action describing the interaction of two D-particles to the sum of elliptic integrals depending on simple kinematic invariants. This representation gives explicitly all alpha' corrections to D-particle dynamics. The alpha' corrections induce a stabilization of the classical trajectories such as the ``eikonal'' which are unstable within the Yang-Mills approximation.Comment: 17 pages, Latex, 6 figure

Large-N bounds on, and compositeness limit of, gauge and gravitational interactions

In a toy model of gauge and gravitational interactions in $D \ge 4$ dimensions, endowed with an invariant UV cut-off $\Lambda$, and containing a large number $N$ of non-self-interacting matter species, the physical gauge and gravitational couplings at the cut-off, $\alpha_g \equiv g^2 \Lambda^{D-4}$ and $\alpha_G \equiv G_N \Lambda^{D-2}$, are shown to be bounded by appropriate powers of ${1\over N}$. This implies that the infinite-bare-coupling (so-called compositeness) limit of these theories is smooth, and can even resemble our world. We argue that such a result, when extended to more realistic situations, can help avoid large-N violations of entropy bounds, solve the dilaton stabilization and GUT-scale problems in superstring theory, and provide a new possible candidate for quintessence.Comment: 8 pages, Latex, minor modifications in notations and reference

Separaxion anxiety in pediatric migraine without aura: A pilot study

Background: Separation anxiety (SA) can be defined as the fear reaction and protest manifested by children when the main caregivers move away from him/her or in front of unfamiliar person. SA near eight months may be considered as an important and normal phase of the correct and typical social neurodevelopment. Aims of the present pilot study is assessing the prevalence of separation anxiety in a population of patients with migraine without aura (MwA). Materials and methods: 119 children (69 males) suffering from MwA (mean age 1.78 ± 7:59) were consecutively recruited. The control population consisted of 231 (114 males) healthy subjects similar for age (7.64 ± 1:34; p = 0.768) and gender (p=0.987) The Screen for child anxiety related emotional disorders (SCARED) test was used to assess the prevalence of separation anxiety among MwA children. Results: Healthy individuals are on average less affected (mean 4.72 ± 0:32) of the Separation Anxiety Disorder respect of MwA children (mean 6.83 ± 0.97; p < 0.001) (Figure 1). Conclusion. MwA presents many psychiatric comorbidities and among ones separation anxiety may be considered in the clinical and therapeutic management of pediatric primary headache

PROFITING FROM CUSTOMER DATA: A PROPOSED RESEARCH AGENDA

The unprecedented volume of data captured by modern hospitality firms during the co-production of the service experience can be used to create economic value. In this article we describe two frameworks grounded in the cross-disciplinary literature in information systems, strategy and marketing, that can help in conceptualizing future research directions in this area. In the first framework, the IS cycle describes the process by which data, generated by transaction processing systems, become the basis for future analyses and initiatives. The second framework enables a disciplined industry analysis by allowing for joint evaluation of the theoretical repurchase rate, degree of customizability of products and services, and degree of unobtrusive data capture that characterizes a given firm’s value proposition. This paper focuses on setting the theoretical framework of reference. A discussion of future research directions and propositions is reserved for the conference presentation due to space limitations

From perfect to fractal transmission in spin chains

Perfect state transfer is possible in modulated spin chains, imperfections however are likely to corrupt the state transfer. We study the robustness of this quantum communication protocol in the presence of disorder both in the exchange couplings between the spins and in the local magnetic field. The degradation of the fidelity can be suitably expressed, as a function of the level of imperfection and the length of the chain, in a scaling form. In addition the time signal of fidelity becomes fractal. We further characterize the state transfer by analyzing the spectral properties of the Hamiltonian of the spin chain.Comment: 8 pages, 10 figures, published versio