The secret language of destiny: stress imprinting and transgenerational origins of disease

Epigenetic regulation modulates gene expression without altering the DNA sequence to facilitate rapid adjustments to dynamically changing environmental conditions. The formation of an epigenetic memory allows passing on this information to subsequent generations. Here we propose that epigenetic memories formed by adverse environmental conditions and stress represent a critical determinant of health and disease in the F3 generation and beyond. Transgenerational programming of epigenetic regulation may represent a key to understand adult-onset complex disease pathogenesis and cumulative effects of life span and familial disease etiology. Ultimately, the mechanisms of generating an epigenetic memory may become of potentially promising diagnostic and therapeutic relevance due to their reversible nature. Exploring the role of environmental factors, such as stress, in causing variations in epigenetic profiles may lead to new avenues of personalized, preventive medicine based on epigenetic signatures and interventions

Quantum jumps induced by the center-of-mass motion of a trapped atom

We theoretically study the occurrence of quantum jumps in the resonance fluorescence of a trapped atom. Here, the atom is laser cooled in a configuration of level such that the occurrence of a quantum jump is associated to a change of the vibrational center-of-mass motion by one phonon. The statistics of the occurrence of the dark fluorescence period is studied as a function of the physical parameters and the corresponding features in the spectrum of resonance fluorescence are identified. We discuss the information which can be extracted on the atomic motion from the observation of a quantum jump in the considered setup

Size-structured populations: immigration, (bi)stability and the net growth rate

We consider a class of physiologically structured population models, a first order nonlinear partial differential equation equipped with a nonlocal boundary condition, with a constant external inflow of individuals. We prove that the linearised system is governed by a quasicontraction semigroup. We also establish that linear stability of equilibrium solutions is governed by a generalized net reproduction function. In a special case of the model ingredients we discuss the nonlinear dynamics of the system when the spectral bound of the linearised operator equals zero, i.e. when linearisation does not decide stability. This allows us to demonstrate, through a concrete example, how immigration might be beneficial to the population. In particular, we show that from a nonlinearly unstable positive equilibrium a linearly stable and unstable pair of equilibria bifurcates. In fact, the linearised system exhibits bistability, for a certain range of values of the external inflow, induced potentially by All\'{e}e-effect.Comment: to appear in Journal of Applied Mathematics and Computin

Topographical disorientation after ischemic mini infarct in the dorsal hippocampus: whispers in silence

Open access journalSilent focal ischemic mini infarcts in the brain are thought to cause no clinically overt symptoms. Some populations of hippocampal cells are particularly sensitive to ischemic events, however, rendering hippocampal functions especially vulnerable to ischemiainduced deficits. The present study investigated whether an otherwise silent ischemic mini infarct in the hippocampus (HPC) can produce impairments in spatial performance in rats. Spatial performance was assessed in the ziggurat task (ZT) using a 10-trial spatial learning protocol for 4 days prior to undergoing hippocampal ischemic lesion or sham surgery. Hippocampal silent ischemia was induced by infusion of endothelin-1 (ET-1), a potent vasoconstrictor, into either the dorsal or the ventral hippocampus (dHPC and vHPC). When tested postoperatively in the ZT using a standard testing protocol for 8 days, rats with hippocampal lesions exhibited no spatial deficit. Although spatial learning and memory in the ZT were not affected by the ET-1-induced silent ischemia, rats with dHPC stroke showed more returns when navigating the ZT as opposed to the vHPC rats. Comparison of region-specific HPC lesions in the present study indicated that dorsal hippocampal function is critically required for topographic orientation in a complex environment. Topographic disorientation as reflected by enhanced return behaviors may represent one of the earliest predictors of cognitive decline after silent ischemic insult that may be potentially traced with sensitive clinical examination in humans.Ye

Real and Virtual Compton Scattering off the Nucleon

A review is given of the very recent developments in the fields of real and virtual Compton scattering off the nucleon. Both real and virtual Compton scattering reactions are discussed at low outgoing photon energy where one accesses polarizabilities of the nucleon. The real Compton scattering at large momentum transfer is discussed which is asymptotically a tool to obtain information on the valence quark wave function of the nucleon. The rapid developments in deeply virtual Compton scattering and associated meson electroproduction reactions at high energy, high photon virtuality and small momentum transfer to the nucleon are discussed. A unified theoretical description of those processes has emerged over the last few years, which gives access to new, generalized parton distributions. The experimental status and perspectives in these fields are also discussed.Comment: 25 pages, 17 figure

Precise Measurements of Beam Spin Asymmetries in Semi-Inclusive π0\pi^0 production

We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial $\sin \phi_h$ amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle $\phi_h$ of the produced neutral pion. The dependence of this amplitude on Bjorken $x$ and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.Comment: to be submitted PL