From the womb into the world:Protecting the fetal brain from maternal stress during pregnancy

No other period in a child's life matches the speed of brain development than the first nine months in the womb. Rapid growth goes hand in hand with enormous potential, but also with great vulnerability. This policy-focused review focuses on maternal mental health as a key factor for fetal brain development. Already during pregnancy, the fetal brain wires differently when exposed to maternal stress, and children prenatally exposed to stress have a higher risk of developing neurodevelopmental disorders. Maternal prenatal stress is preventable, treatable, and tractable by policy. Research-based, policy recommends: (1) screening for maternal mental health issues throughout pregnancy, (2) encourage talking about prenatal mental health, (3) evidence-based interventions for pregnant women with mental health issues, (4) avoiding stress-inducing communication towards pregnant women, and (5) stimulating positive postnatal parenting. Investing in healthy pregnancies will improve fetal brain growth, and, ultimately lead to a healthier next generation

Properties of Deflagration Fronts and Models for Type Ia Supernovae

Detailed models of the explosion of a white dwarf, which include self-consistent calculations of the light curve and spectra, provide a link between observational quantities and the underlying explosion.These calculations assume spherical geometry and are based on parameterized descriptions of the burning front during the deflagration phase. Recently, first multi-dimensional calculations for nuclear burning fronts have been performed. Although a fully consistent treatment of the burning fronts is beyond the current state of the art, these calculations provided a new and better understanding of the physics, and new descriptions for the flame propagation have been proposed. Here, we have studied the influence on the results of previous analyses of Type Ia Supernovae, namely, the nucleosynthesis and structure of the expanding envelope. Our calculations are based on a set of delayed detonation models with parameters that give a good account of the optical and infrared light curves, and of the spectral evolution. In this scenario, the burning front propagates first in a deflagration mode and, subsequently, turns into a detonation. The explosions and light curves are calculated using a one-dimensional Lagrangian radiation-hydro code, including a detailed nuclear network.Comment: 9 pages, 4 figures, macros 'crckapb.sty'. The Astrophysical Journal (accepted

Acceleration of mass transfer in methane-producing loop reactors

Gas bubbles entrapped in methanogenic granules subjected to hydrostatic pressure oscillations during recirculation in loop reactors will induce intraparticle liq. flows and thereby enhance mass transfer in excess of diffusion. This 'breathing particle' concept was clearly demonstrated in a well defined inorg. model system. The exptl. results could be described satisfactory with a structured math. model, in which a 30% improvement is predicted for methanogenic loop reactors as compared to const. pressure systems. It is concluded that acceleration of mass transfer in gas-producing systems offers challenging perspectives for both heterogeneous catalysis and biol. fermns. [on SciFinder (R)

The host galaxy of GRB010222: The strongest damped Lyman-alpha system known

Analysis of the absorption lines in the afterglow spectrum of the gamma-ray burst GRB010222 indicates that its host galaxy (at a redshift of z=1.476) is the strongest damped Lyman-alpha (DLA) system known, having a very low metallicity and modest dust content. This conclusion is based on the detection of the red wing of Lyman-alpha plus a comparison of the equivalent widths of ultraviolet Mg I, Mg II, and Fe II lines with those in other DLAs. The column density of H I, deduced from a fit to the wing of Lyman-alpha, is (5 +/- 2) 10^22 cm^-2. The ratio of the column densities of Zn and Cr lines suggests that the dust content in our line of sight through the galaxy is low. This could be due to either dust destruction by the ultraviolet emission of the afterglow or to an initial dust composition different to that of the diffuse interstellar material, or a combination of both.Comment: Submitted to MNRAS 12 page

The Possible White Dwarf-Neutron Star Connection

The current status of the problem of whether neutron stars can form, in close binary systems, by accretion-induced collapse (AIC) of white dwarfs is examined. We find that, in principle, both initially cold C+O white dwarfs in the high-mass tail of their mass distribution in binaries and O+Ne+Mg white dwarfs can produce neutron stars. Which fractions of neutron stars in different types of binaries (or descendants from binaries) might originate from this process remains uncertain.Comment: 6 pages. To appear in "White Dwarfs", ed. J. Isern, M. Hernanz, and E. Garcia-Berro (Dordrecht: Kluwer

Precessing microblazars and unidentified gamma-ray sources

The recent discovery by Paredes et al. (2000) of a persistent microquasar that is positionally coincident with an unidentified gamma-ray source has open the possibility that other sources in the Third EGRET Catalog could be interpreted as microquasars as well. In this letter we show that some variable unidentified EGRET sources in the galactic plane could be produced by faint, otherwise undetected microquasars with precessing jets. When the jet points towards the observer, gamma-ray emission resulting from upscattered stellar photons could be detectable yielding a variable source with weak or undetectable counterpart at longer wavelengths. Strategies for detecting these``microblazars'' with forthcoming satellites are briefly discussed.Comment: 4 pages, 3 figures, Astronomy & Astrophysics Letters in press, typing errors correctio