Computation of torsional vibration modes of Ranger and Surveyor space vehicles

Mathematical model for calculating free torsion modes of Atlas Agena Ranger and Atlas Centaur Surveyor spacecraft

Transient Elevation of Corticosterone Alters Begging Behavior and Growth of White-Crowned Sparrow Nestlings

Developing animals may face a cost–benefit tradeoff during growth mediated through hormones such as glucocorticoids, as the hormone is essential for development but can have detrimental consequences. To investigate potential tradeoffs caused by brief, moderate elevations of corticosterone in avian young, we artificially elevated the hormone levels in two ways: feeding corticosterone-containing worms and applying corticosterone dermal patches. The former experiment tested the effects of an acute corticosterone elevation (25 min) on begging behavior, whereas the latter explored the effects of artificially elevated corticosterone for 24 to 48 h on growth. Corticosterone altered both begging behavior and growth of white-crowned sparrow nestlings. It increased latency to beg immediately after the treatment and suppressed growth as early as 24 h after the patch application. These experiments also showed that the effects depended on the age or types of development (e.g. gaining mass or growing feathers) that the nestlings were going through

Time-resolved infrared emission from radiation-driven central obscuring structures in Active Galactic Nuclei

The central engines of Seyfert galaxies are thought to be enshrouded by geometrically thick gas and dust structures. In this article, we derive observable properties for a self-consistent model of such toroidal gas and dust distributions, where the geometrical thickness is achieved and maintained with the help of X-ray heating and radiation pressure due to the central engine. Spectral energy distributions (SEDs) and images are obtained with the help of dust continuum radiative transfer calculations with RADMC-3D. For the first time, we are able to present time-resolved SEDs and images for a physical model of the central obscurer. Temporal changes are mostly visible at shorter wavelengths, close to the combined peak of the dust opacity as well as the central source spectrum and are caused by variations in the column densities of the generated outflow. Due to the three-component morphology of the hydrodynamical models -- a thin disc with high density filaments, a surrounding fluffy component (the obscurer) and a low density outflow along the rotation axis -- we find dramatic differences depending on wavelength: whereas the mid-infrared images are dominated by the elongated appearance of the outflow cone, the long wavelength emission is mainly given by the cold and dense disc component. Overall, we find good agreement with observed characteristics, especially for those models, which show clear outflow cones in combination with a geometrically thick distribution of gas and dust, as well as a geometrically thin, but high column density disc in the equatorial plane.Comment: 16 pages, 12 figures, accepted for publication in MNRA

outlook for fish to 2020

Fish trade ,Fisheries Economic aspects Developing countries ,Fisheries Environmental aspects ,

Fish as food

"This paper reports results of incorporating fish into IMPACT, a global model of food supply and demand that estimates market-clearing prices to 2020 for 32 commodities in 36 regions. It summarizes results for production, consumption, net exports and real price changes for 10 economic categories of fisheries items, disaggregated into 15 geographic regions of the world. Under the medium-variant scenario for the uncertain capture fisheries sectors, global production of food fish is projected to rise by 1.5% annually through 2020, with two-thirds of this from aquaculture, whose share in total food fish production rises to 41%. Global per capita fish consumption is projected to be 17.1 kg in 2020, with sensitivity analysis indicating a margin of 2 kg/capita either way based on extreme scenarios for capture and aquaculture. Most growth will occur in developing countries, which will account for 79% of food fish production in 2020. China's share of world production will continue to expand, while that of Japan, the EU, and former USSR will continue to contract. Real fish prices will rise 4 to 16% by 2020, while meat prices will fall 3%. Fishmeal and oil prices will rise 18%; use of these commodities will increasingly be concentrated in carnivorous aquaculture. Growing domestic demand will dampen fish exports from developing countries. Sensitivity analysis incorporating a very pessimistic view of capture fisheries leads to escalating food fish prices (+69% for high-value finfish) and soaring fishmeal prices (+134%), whereas an optimistic view of increased investment in aquaculture lowers real prices of low value food fish (-12%), and raises fishmeal prices (+42%)." Authors' AbstractFishery production Forecasting ,Food supply ,

Two Phase Collective Modes in Josephson Vortex Lattice in Intrinsic Josephson Junction Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta}

Josephson plasma excitations in the high $T_c$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ have been investigated in a wide microwave frequency region (9.8 -- 75 GHz), in particular, in magnetic field applied parallel to the $ab$ plane of the single crystal. In sharp contrast to the case for magnetic fields parallel to the c axis or tilted from the $ab$ plane, it was found that there are two kinds of resonance modes, which are split in energy and possess two distinctly different magnetic field dependences. One always lies higher in energy than the other and has a shallow minimum at about 0.8 kOe, then increases linearly with magnetic field. On the other hand, another mode begins to appear only in a magnetic field (from a few kOe and higher) and has a weakly decreasing tendency with increasing magnetic field. By comparing with a recent theoretical model the higher energy mode can naturally be attributed to the Josephson plasma resonance mode propagating along the primitive reciprocal lattice vector of the Josephson vortex lattice, whereas the lower frequency mode is assigned to the novel phase collective mode of the Josephson vortex lattice, which has never been observed before.Comment: 11 pages and 10 figure