[en] This volume provides coverage related to radiologic interpretation and the use of radiology in diagnosis. All major radiologic modalities are incorporated

[en] Sensitive SOLARC imaging spectropolarimetric observations from Haleakala reveal a diffuse coronal surface brightness in the He I 1083 nm line. A series of observations suggests that this signal originates from an 'inner source' of neutral helium atoms in the solar corona. Here, we explore the possibility that this cold coronal component originates from helium ions that are neutralized by the near-Sun dust and subsequently excited to the metastable 1s2s ³ S state, which then scatters photons from the solar disk. This picture suggests a deficit of coronal dust inside about 2-4 R_sun in order to account for both the flat radial brightness distribution and the small velocity line width of the observations. We find a strong correlation between the polarized He brightness and coronal white light brightness that supports the argument that electronic collisional excitation of the metastable helium triplet level is responsible for our polarization signal.

[en] Rocky exoplanets are expected to be eroded by space weather in a similar way as in the solar system. In particular, Mercury is one of the dramatically eroded planets whose material continuously escapes into its exosphere and further into space. This escape is well traced by sodium atoms scattering sunlight. Due to solar wind impact, micrometeorite impacts, photo-stimulated desorption and thermal desorption, sodium atoms are released from surface regolith. Some of these released sodium atoms are escaping from Mercury’s gravitational-sphere. They are dragged anti-Sun-ward and form a tail structure. We expect similar phenomena on exoplanets. The hot super-Earth 61 Vir b orbiting a G3V star at only 0.05 au may show a similar structure. Because of its small separation from the star, the sodium release mechanisms may be working more efficiently on hot super-Earths than on Mercury, although the strong gravitational force of Earth-sized or even more massive planets may be keeping sodium atoms from escaping from the planet. Here, we performed model simulations for Mercury (to verify our model) and 61 Vir b as a representative super-Earth. We have found that sodium atoms can escape from this exoplanet due to stellar wind sputtering and micrometeorite impacts, to form a sodium tail. However, in contrast to Mercury, the tail on this hot super-Earth is strongly aligned with the anti-starward direction because of higher light pressure. Our model suggests that 61 Vir b seems to have an exo-base atmosphere like that of Mercury.

[en] Brief item

[en] We propose to extract the Λ form factor by means of the radiative return method profitting from the self analyzing Λ→π^-p (anti Λ→π⁺ anti p) decays. At B-factories, due to their large luminosities, one can expect decent statistics allowing for fairly accurate analysis of that process. The analysis was performed based on the implementation of the process e⁺e^-→Λ(→π^-p) anti Λ(→π⁺ anti p)γ into the PHOKHARA event generator. Both details of the implementation and the analysis will be presented. (orig.)

[en] We present a general and mathematically simple method to control two-level systems. It is based on a piecewise time-independent procedure. We assume that some parameters of an external interaction potential can be rapidly switched at specified time instants, and then kept constant during small time intervals Δt. By properly setting the parameter values, obtained from algebraic, instead of differential or integral, equations, we can drive the time evolution of arbitrary observables. We illustrate the approach with some examples and discuss important technical aspects, relevant in real concrete situations, such as the robustness of the method to errors in the control parameter values, the influence of the switching mechanism transient times, the appropriate choice for the Δt's, and so on

[en] Cerebral cavernous malformations (CCM) are common, mostly benign vascular anomalies of the CNS. Clinical features are seizures, headache and focal neurological signs. Often they are asymptomatic. Apart from sporadically cases CCM occur as an autosomal dominant condition. Familial cases are associated with a high frequency of multiple lesions. MRI is most sensitive in the detection of cavernous malformations. The MRI findings of CCM are variable, depending on hemorrhage and calcifications. The typical appearance of CCM are heterogenous ''popcorn-like'' lesions of different size with a mixed signal core and a hypointense hemosiderin rim. Our report concerns a 22 year old man with multiple cerebral cavernous malformations whose follow-up MRI of brain showed the appearance of a new lesion. (orig.)

[en] The G0 parity violation experiment at Jefferson Lab is based on time-of-flight measurements, and is sensitive to timing effects between the two electron helicity states of the beam. Photon counters triggered by time-of-arrival at the target mandate that timing must be independent of delays associated with different orbits taken by the two helicity states. In addition, the standard 499 MHz beam structure is altered such that 1 of every 16 microbunches are filled, resulting in an arrival frequency of 31.1875 (31) MHz, and an average current of 40 μA. Helicity correction involves identifying and tracking the 31 MHz sub-harmonic, applying a fast/fine phase correction, and finally producing a clean 31 MHz trigger and a 499 MHz clock train. These signals are phase-matched to the beam arrival at the target on the order of femtoseconds. The 10 kHz output bandwidth is sufficiently greater than the 30 Hz helicity flip settling time (500 μs). This permits the system to correct each helicity bin for any orbit-induced timing inequalities. A sampling phase detection scheme is used in order to eliminate the unavoidable 2n/n phase shifts associated with frequency dividers. Conventional receiver architecture and DSP techniques are combined for maximum sensitivity, bandwidth, and flexibility. Results of bench tests, commissioning and production data will be presented

[en] The European XFEL project is a 4. generation light source. The first beam will be delivered in the beginning of 2015 and will produce spatially coherent ≤ 80 fs short photon pulses with a peak brilliance of 10³²-10³⁴ photons/s/mm²/mrad²/0.1% BW in the energy range from 0.26 to 29 keV at electron beam energies 10.5 GeV, 14 GeV or 17.5 GeV. Three undulator systems SASE 1, SASE 2 and SASE 3 are used to produce photon beams. Each undulator system consists of an array of undulator cells installed in a row along the electron beam. A single undulator cell itself consists of a planar undulator, a phase shifter, magnetic field correction coils and a quadrupole mover. The local control system of the undulator cell is based on industrial components produced by Beckhoff Automation GmbH and a PLC implemented in the TwinCAT system. Four servo motors control the gap between the girders on each undulator with micrometer accuracy. One stepper motor is used for phase shifter control, and two other stepper motors control the position of the quadrupole magnet. The current of magnetic field correction coils as well as the gap of the phase shifter are adjustable as a function of the undulator gap. The high level of synchronization (1 μs) for the complete undulator system (for instance SASE 2 with 35 undulator cells in total) can be achieved due to the implementation of a fast EtherCAT field-bus system in the local control. (authors)

[en] We show here that the absorptive Hα polarized line profile previously seen in many Herbig Ae/Be (HAeBe) stars is a nearly ubiquitous feature of other types of embedded or obscured stars. This characteristic 1% linear polarization variation across the absorptive part of the Hα line is seen in post-AGB stars as well as RV Tau, δ Scuti, and other types. Each of these stars shows evidence of obscuration by intervening circumstellar hydrogen gas and the polarization effect is in the absorptive component, consistent with an optical pumping model. We present ESPaDOnS spectropolarimetric observations of nine post-AGB and RV Tau types in addition to many multi-epoch HiVIS observations of these targets. We find significant polarization changes across the Hα line in 8/9 stars with polarization amplitudes of 0.5% to over 3% (5/6 post-AGB and 3/3 RV Tau). In all but one of these, the polarization change is dominated by the absorptive component of the line profile. There is no evidence that subclasses of obscured stars showing stellar pulsations (RV Tau for post-AGB stars and δ Scuti for Herbig Ae/Be stars) show significant spectropolarimetric differences from the main class. Significant temporal variability is evident from both HiVIS and ESPaDOnS data for several stars presented here: 89 Her, AC Her, SS Lep, MWC 120, AB Aurigae, and HD144668. The morphologies and temporal variability are comparable to existing large samples of Herbig Ae/Be and Be type stars. Since post-AGB stars have circumstellar gas that is very different from Be stars, we discuss these observations in the context of their differing environments.