iTRAQ-based proteomic profiling of the marine medaka (Oryzias melastigma) gonad exposed to BDE-47

A recent study demonstrated that 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) may have an adverse effect on the reproduction in marine medaka (Oryzias melastigma), but the molecular mechanisms remain largely unknown. In this study, we investigated the protein expression profiles of male and female gonads of O. melastigma exposed to dietary BDE-47 at two dosages (0.65 and 1.30 μg/g/day, respectively) for 21 days. Extracted proteins were labeled with iTRAQ and analyzed on a MALDI TOF/TOF analyzer, as results, 133 and 144 unique proteins were identified in testis and ovary, respective, and they exerted dose- and sex-dependent expression patterns. In testis, among the 42 differentially expressed proteins; down-regulation of histone variants and parvalbumins implicated BDE-47 may disrupt the spermatogenesis and induce sterility in fishes. In ovary, 38 proteins were differentially expressed; the elevation of vitellogenins and apolipoprotein A–I expression indicated BDE-47 acts as an estrogen-mimicking compound and led to reproductive impairment in O. melastigma.     

Pre-Breakdown Processes in the Hollow Cathode Region of a Transient Hollow Cathode Discharge

Discharge formation in the A–K space of transient hollow cathode discharge (THCD) is causally linked with the emission of high energy electron beams originating in the hollow cathode region (HCR). Ionization in the A–K gap proceeds through the formation of a moving virtual anode, whose time evolution is strongly correlated with different periods in the electron beam activity. Here, we report on time and space resolved observations of different ionization events inside the HCR, which are time correlated with ionization processes inside the A–K gap. The experiments have been performed in Hydrogen, at pressures between 50 and 400 mTorr. A statistical study of the characteristic times associated with the different ionization events, based on von Laue plots, shows that the time distribution of events is well described by a single Gaussian distribution.     

Resonant Compton upscattering in anomalous X-ray pulsars

A significant new development in the study of Anomalous X-ray Pulsars (AXPs) has been the recent discovery by INTEGRAL and RXTE of flat, hard X-ray components in three AXPs. These non-thermal spectral components differ dramatically from the steeper quasi-power-law tails seen in the classic X-ray band in these sources. A prime candidate mechanism for generating this new component is resonant, magnetic Compton upscattering. This process is very efficient in the strong magnetic fields present in AXPs. Here an introductory exploration of an inner magnetospheric model for upscattering of surface thermal X-rays in AXPs is offered, preparing the way for an investigation of whether such resonant upscattering can explain the 20–150 keV spectra seen by INTEGRAL. Characteristically flat emission spectra produced by non-thermal electrons injected in the emission region are computed using collision integrals. A relativistic QED scattering cross section is employed so that Klein–Nishina reductions are influential in determining the photon spectra and fluxes. Spectral results depend strongly on the magnetospheric locale of the scattering and the observer’s orientation, which couple directly to the angular distributions of photons sampled.     

TOWARD A STATUS-OF-WOMEN INDEX

A useful index of the status of women should be mappable, in order to allow global and regional comparisons. Ideally, such an index should include political, economic, and social components. In actuality, data that measure political and economic equality are available only in Western societies. An index that measures the general well-being of women, however, can be mapped and used crossculturally. An index is proposed that includes indicators from the areas of health, education and fertility.     

Towards identifying sources of subsurface flow: A comparison of components identified by a physically based runoff model and those determined by chemical mixing techniques

A physically-based semidistributed model, TOPMODEL, is applied to a 340 hectare spruce forested catchment in mid-Wales. the model is calibrated to runoff and the subsurface flow is divided into components of flow identified by depth of origin. in addition, chemical mixing techniques are used to provide a hydrograph separation between acidic soil waters and well buffered deep waters. the short-term variations in the components of flow identified by these two approaches compare well.     

The vertical structure of planet-induced gaps in protoplanetary discs

Giant planets embedded in circumstellar discs are expected to open gaps in these discs. We examine the vertical structure of the gap edges. We find that the planet excites spiral arms with significant (Mach number of a half) vertical motion of the gas, and discuss the implications of these motions. In particular, the spiral arms will make the edge appear 'puffed up' relative to the bulk of the disc. Infrared observations (sensitive to dust) would be dominated by the light from the thick inner edge of the disc. Submillimetre observations (sensitive to gas velocities) would appear to be hot in 'turbulent' motions (actually the ordered motion caused by the passage of the spiral arms), but cold in chemistry. Resolved submillimetre maps of circumstellar discs might even be able to detect the spiral arms directly.     

Reducing the probability of capture into resonance

A migrating planet can capture planetesimals into mean motion resonances. However, resonant trapping can be prevented when the drift or migration rate is sufficiently high. Using a simple Hamiltonian system for first- and second-order resonances, we explore how the capture probability depends on the order of the resonance, drift rate and initial particle eccentricity. We present scaling factors as a function of the planet mass and resonance strength to estimate the planetary migration rate above which the capture probability drops to less than half. Applying our framework to multiple extrasolar planetary systems that have two planets locked in resonance, we estimate lower limits for the outer planet's migration rate, allowing resonance capture of the inner planet.
Mean motion resonances are comprised of multiple resonant subterms. We find that the corotation subterm can reduce the probability of capture when the planet eccentricity is above a critical value. We present factors that can be used to estimate this critical planet eccentricity. Applying our framework to the migration of Neptune, we find that Neptune's eccentricity is near the critical value that would make its 2 : 1 resonance fail to capture twotinos. The capture probability is affected by the separation between resonant subterms and so is also a function of the precession rates of the longitudes of periapse of both planet and particle near resonance.     

Arecibo radar observations of Phobos and Deimos

In November 2005, we observed the moons of Mars using the Arecibo 2380-MHz (13-cm) radar, obtaining a result for the OC radar albedo of Phobos (0.056±0.014) consistent with its previously reported radar albedo and implying an upper bound on its near-surface bulk density of . We detected Deimos by radar for the first time, finding its OC radar albedo to be 0.021±0.006, implying an upper bound on its near-surface density of , consistent with a high-porosity regolith. We briefly discuss reasons for these low radar albedos, Deimos' being possibly the lowest of any Solar System body yet observed by radar.     

Radar observations of Itokawa in 2004 and improved shape estimation

Abstract— We present June 2004 radar images of asteroid 25143 Itokawa (1998 SF36) that improve upon the longitude‐latitude coverage of images obtained in 2001 by Ostro et al. (2004) and use the 2001–2004 data to refine that paper's constraints on Itokawa's shape. The 2004 images, the first of the asteroid's southern side, look distinctly different from the 2001 images, revealing leading edges that are much more curved and rugged than the nearly convex leading edges seen at northern latitudes in 2001. Itokawa is shaped like a slightly asymmetrical, bent, lumpy ellipsoid with dimensions along the principal axes within 10% of 594 times 320 times 288 m. To illustrate the uncertainty space associated with shape reconstruction from images with suboptimal orientational coverage, we present two alternative three‐dimensional models of the object.     

The α-effect in 2D fast dynamos

We look at the large-scale dynamo properties of spatially periodic, time dependent, helical 2D flows of the form u(x, t)?=?(? _y ?ψ?(x, y, t), ?? _x ?ψ?(x, y, t), ?ψ (x, y, t). These flows act as kinematic fast dynamos and are able to generate a mean magnetic field uniform and constant in the xy-plane but whose direction varies periodically along z with wavenumber k. Using Mean Field Electrodynamics, the generation mechanism can be understood in terms of a k-dependent α-effect, which depends on the magnetic Reynolds number, R _m . We calculate this effect for different motions and investigate how its limit as k?→?0 depends on R _m and on the properties of the flows such as their spatial structure or correlation time. This work generalises earlier studies based on 2D steady flows to motions with time dependence.