CMB anisotropies in the presence of a stochastic magnetic field

Primordial magnetic fields present since before the epoch of matter-radiation equality have an effect on the anisotropies of the cosmic microwave background. The CMB anisotropies due to scalar perturbations are calculated in the gauge invariant formalism for magnetized adiabatic initial conditions. Furthermore the linear matter power spectrum is calculated. Numerical solutions are complemented by a qualitative analysis.Comment: 26 pages, 21 figures; sections 2 and 4 expanded; matches version published in PR

The Slowdown in Productivity Growth: Analysis of Some Contributing factors

macroeconomics,product growth

Electronic transport properties through thiophenes on switchable domains

The electronic transport of electrons and holes through stacks of $\alpha$,\ome ga-dicyano-$\beta$,$\beta$'-dibutyl- quaterthiophene (DCNDBQT) as part of a nov el organic ferroic field-effect transistor (OFFET) is investigated. The novel ap plication of a ferroelectric instead of a dielectric substrate provides the poss ibility to switch bit-wise the ferroelectric domains and to employ the polarizat ion of these domains as a gate field in an organic semiconductor. A device conta ining very thin DCNDBQT films of around 20 nm thickness is intended to be suitab le for logical as well as optical applications. We investigate the device proper ties with the help of a phenomenological model called multilayer organic light-e mitting diodes (MOLED), which was extended to transverse fields. The results sho wed, that space charge and image charge effects play a crucial role in these org anic devices

Cavity Reactor Engineering Mockup Critical Experiment

Critical mass of uranium 235 for stainless steel lined cavities in nuclear research and test reactors with heavy water reflecto

Effect of Drying on Grain Quality -- Moisture Readsorption Causes Fissured Rice Grains

Among others, drying can affect the quality of rice or other cereal grains (with a hard vitreous endosperm) in three prevalent and distinctive ways. These are:1. Through Moisture Readsorption by Dry Rice Grains: Rice, as well as other cereal grains, is hygroscopic. The low-moisture (dried) grain readsorbs moisture from any source to which it is exposed. Moisture adsorbed through the grain surface causes the starch cells to expand and produce compressive stresses. Since the grain is a "free body", compressive stresses are countered by equal but opposite tensile stresses at the grain centre. When the compressive stresses at the surface exceed the tensile strength of the grain at its centre, a fissure develops. Fissured grains usually break during milling. Sources for grain moisture readsorption are discussed.2. Through Moisture Readsorption by Field Rice Grains:  When rice grains in the field reach harvest moisture (22%), the field sample may contain grains with moisture contents (MC) between 15 and 45%.  Many individual grains may dry to below 15% MC during the day.  Such grains can fissure on the stalk when they readsorb moisture at night.3. Through Rapid Drying (To near storage moisture): Rapid drying produces a steep moisture gradient in the grain. As this gradient reclines after drying, the grain surface receives moisture from the interior and expands while the grain interior loses moisture and contracts. As this combination of stresses (compressive at the surface and tensile at the centre) develops with time, the grain fails in tension by pulling itself apart at its centre. The rheological aspects (stress, strain and time) that cause the grain failure are discussed.Most breakage in rice processing can be attributed to grains which were fissured before milling.  Moisture readsorption by low-moisture grains in the field before harvest is the most prevalent cause of fissured grains.  Mechanical harvesting at a higher moisture content can minimize this type of grain failure. -- Fissuring of the rice grain after drying can be controlled by the drying procedure.  Rapid drying which leaves a steep moisture gradient in the grain at the end of drying will cause the grain to fissure after drying.  With time the grain fails in tension.  Rice drying should not be terminated with a steep moisture gradient in the grain

Life-cycle patterns in male/female differences in job search

We investigate whether women search longer for a job than men and whether these differences change over the life cycle. Our empirical analysis exploits German register data on highly attached displaced workers. We apply duration models to analyze gender differences in job search taking into account observed and unobserved worker heterogeneity and censoring. Simple survival functions show that displaced women take longer to find a new job than comparable men. Disaggregation by age groups reveals that these differences are driven by differential behavior of prime age women. There is no significant difference in job search duration among the very young and older workers. These differential outcomes remain even after we control for differences in human capital, and when time dependence and unobserved heterogeneity are incorporated into the model