Coexistence of periods in a bisecting bifurcation

The inner structure of the attractor appearing when the Varley-Gradwell-Hassell population model bifurcates from regular to chaotic behaviour is studied. By algebraic and geometric arguments the coexistence of a continuum of neutrally stable limit cycles with different periods in the attractor is explained.Comment: 13 pages, 5 figure

A Novel Kind of Neutrino Oscillation Experiment

A novel method to look for neutrino oscillations is proposed based on the elastic scattering process $\bar{\nu}_{i} e^{-}\rightarrow \bar{\nu}_{i} e^{-}$, taking advantage of the dynamical zero present in the differential cross section for $\bar{\nu}_{e} e^{-}\rightarrow \bar{\nu}_{e} e^{-}$. An effective tunable experiment between the "appearance" and "disappearance" limits is made possible. Prospects to exclude the allowed region for atmospheric neutrino oscillations are given.Comment: 11 pages (+3 figures, available upon request),Standard Latex, FTUV/94-3

Families of piecewise linear maps with constant Lyapunov exponent

We consider families of piecewise linear maps in which the moduli of the two slopes take different values. In some parameter regions, despite the variations in the dynamics, the Lyapunov exponent and the topological entropy remain constant. We provide numerical evidence of this fact and we prove it analytically for some special cases. The mechanism is very different from that of the logistic map and we conjecture that the Lyapunov plateaus reflect arithmetic relations between the slopes.Comment: 26 pages, 13 figure

Generational Mass Splitting of Neutrinos in High Temperature SU(2)L⊗U(1)SU(2)_{\scriptscriptstyle{L}}\otimes U(1) Gauge Theory

We calculate the generational mass splitting of neutrinos in high temperature $SU(2)_{\scriptscriptstyle{L}}\otimes U(1)$ gauge theory when the temperature is above $250$ GeV and the gauge symmetry is restored. We consider the case of neutrinos that are massless at tree level as well as the case of neutrinos with tree-level mass and large mixing.Comment: 12 Pages, JHU-TIPAC-940008/INFNCA-TH-94-

Bifurcations in the Lozi map

We study the presence in the Lozi map of a type of abrupt order-to-order and order-to-chaos transitions which are mediated by an attractor made of a continuum of neutrally stable limit cycles, all with the same period.Comment: 17 pages, 12 figure

Emergence of hierarchical networks and polysynchronous behaviour in simple adaptive systems

We describe the dynamics of a simple adaptive network. The network architecture evolves to a number of disconnected components on which the dynamics is characterized by the possibility of differently synchronized nodes within the same network (polysynchronous states). These systems may have implications for the evolutionary emergence of polysynchrony and hierarchical networks in physical or biological systems modeled by adaptive networks.Comment: 4 pages, 4 figure

The Arabidopsis Synaptotagmin1 is enriched in endoplasmic reticulum-plasma membrane contact sites and confers cellular resistance to mechanical stresses

Eukaryotic endoplasmic reticulum (ER)-plasma membrane (PM) contact sites are evolutionarily conserved microdomains that have important roles in specialized metabolic functions such as ER-PM communication, lipid homeostasis, and Ca2+ influx. Despite recent advances in knowledge about ER-PM contact site components and functions in yeast (Saccharomyces cerevisiae) and mammals, relatively little is known about the functional significance of these structures in plants. In this report, we characterize the Arabidopsis (Arabidopsis thaliana) phospholipid binding Synaptotagmin1 (SYT1) as a plant ortholog of the mammal extended synaptotagmins and yeast tricalbins families of ER-PM anchors. We propose that SYT1 functions at ER-PM contact sites because it displays a dual ER-PM localization, it is enriched in microtubule-depleted regions at the cell cortex, and it colocalizes with Vesicle-Associated Protein27-1, a known ER-PM marker. Furthermore, biochemical and physiological analyses indicate that SYT1 might function as an electrostatic phospholipid anchor conferring mechanical stability in plant cells. Together, the subcellular localization and functional characterization of SYT1 highlights a putative role of plant ER-PM contact site components in the cellular adaptation to environmental stresses

Supernova Neutrino Oscillations

Observing a high-statistics neutrino signal from a galactic supernova (SN) would allow one to test the standard delayed explosion scenario and may allow one to distinguish between the normal and inverted neutrino mass ordering due to the effects of flavor oscillations in the SN envelope. One may even observe a signature of SN shock-wave propagation in the detailed time-evolution of the neutrino spectra. A clear identification of flavor oscillation effects in a water Cherenkov detector probably requires a megatonne-class experiment.Comment: Proc. 129 Nobel Symposium "Neutrino Physics", 19-24 Aug 2004, Swede