Assessment of damage domains of the High-Temperature Engineering Test Reactor (HTTR)

This paper presents an assessment analysis of damage domains of the 30 MWth prototype High-Temperature Engineering Test Reactor (HTTR) operated by the Japan Atomic Energy Agency (JAEA). For this purpose, an in-house deterministic risk assessment computational tool was developed based on the Theory of Stimulated Dynamics (TSD). To illustrate the methodology and applicability of the developed modelling approach, assessment results of a control rod (CR) withdrawal accident during subcritical conditions are presented and compared with those obtained by the JAEA.

Infiltration of a photonic crystal fiber with cholesteric liquid crystal and blue phase

Photonic crystal fibers (PCF) have been selectively filled with a cholesteric liquid crystal (ChLC) with special interest in the blue phase (BP) of the liquid crystal. It has been observed thermal tuning of the guided light in the visible region. A dramatically enhance appears when the phase of the liquid crystal changes from cholesteric to blue phase I (BPI). When a thermal range of the blue phase I is achieved, no changes are observed while increasing temperature from BPI through BPII and to the isotropic phase.

Imaging of H217O distribution in the brain of a live rat by using proton-detected 17O MRI

Imaging of H217O has a number of important applications. Mapping the distribution of H217O produced by oxidative metabolism of 17O-enriched oxygen gas may lead to a new method of metabolic functional imaging; regional cerebral blood flow also can be measured by measuring the H217O distribution after the injection of 17O-enriched physiological saline solution. Previous studies have proposed a method for indirect detection of 17O. The method is based on the shortening of the proton T2 in H217O solutions, caused by the residual 17O-1H scalar coupling and transferred to the bulk water via fast chemical exchange. It has been shown that the proton T2 of H217O solutions can be restored to that of H216O by irradiating the resonance frequency of the 17O nucleus. The indirect 17O image thus is obtained by taking the difference between two T2-weighted spin-echo images: one acquired after irradiation of the 17O resonance and one acquired without irradiation. It also has been established that, at relatively low concentrations of H217O, the indirect method yields an image that quantitatively reflects the H217O distribution in the sample. The method is referred to as PRIMO (proton imaging of oxygen). In this work, we show in vivo proton images of the H217O distribution in a rat brain after an i.v. injection of H217O-enriched physiological saline solution. Implementing the indirect detection method in an echo-planar imaging sequence enabled obtaining H217O images with good spatial and temporal resolution of few seconds.

Retinotopic mapping of lateral geniculate nucleus in humans using functional magnetic resonance imaging

Subcortical nuclei in the thalamus, which play an important role in many functions of the human brain, provide challenging targets for functional mapping with neuroimaging techniques because of their small sizes and deep locations. In this study, we explore the capability of high-resolution functional magnetic resonance imaging at 4 Tesla for mapping the retinotopic organization in the lateral geniculate nucleus (LGN). Our results show that the hemifield visual stimulation only activates LGN in the contralateral hemisphere, and the lower-field and upper-field visual stimulations activate the superior and inferior portion of LGN, respectively. These results reveal a similar retinotopic organization between the human and nonhuman primate LGN and between LGN and the primary visual cortex. We conclude that high-resolution functional magnetic resonance imaging is capable of functional mapping of suborganizations in small nuclei together with cortical activation. This will have an impact for studying the thalamocortical networks in the human brain.

An approach to probe some neural systems interaction by functional MRI at neural time scale down to milliseconds

In this paper, we demonstrate an approach by which some evoked neuronal events can be probed by functional MRI (fMRI) signal with temporal resolution at the time scale of tens of milliseconds. The approach is based on the close relationship between neuronal electrical events and fMRI signal that is experimentally demonstrated in concurrent fMRI and electroencephalographic (EEG) studies conducted in a rat model with forepaw electrical stimulation. We observed a refractory period of neuronal origin in a two-stimuli paradigm: the first stimulation pulse suppressed the evoked activity in both EEG and fMRI signal responding to the subsequent stimulus for a period of several hundred milliseconds. When there was an apparent site–site interaction detected in the evoked EEG signal induced by two stimuli that were primarily targeted to activate two different sites in the brain, fMRI also displayed signal amplitude modulation because of the interactive event. With visual stimulation using two short pulses in the human brain, a similar refractory phenomenon was observed in activated fMRI signals in the primary visual cortex. In addition, for interstimulus intervals shorter than the known latency time of the evoked potential induced by the first stimulus (≈100 ms) in the primary visual cortex of the human brain, the suppression was not present. Thus, by controlling the temporal relation of input tasks, it is possible to study temporal evolution of certain neural events at the time scale of their evoked electrical activity by noninvasive fMRI methodology.

Forecasting migration between the EU, V4 and Eastern Europe. Impact of visa abolition. OSW Report, July 2014

This book is the result of one year of solid work among a multinational research team assembled from seven states (Poland, Czechia, Hungary, Slovakia, Ukraine, Belarus and Moldova). It aims at a detailed analysis of migration patterns and migration forecasts from Ukraine, Belarus and Moldova to the EU/V4. In particular, the nexus between EU visa policy and migration dynamics as well as the impact of economic, political and institutional factors on migration from Eastern Europe have been investigated. The importance of migration policy must be stressed here. Together with demand for the foreign labour force (labour market needs, level of wages, existing work opportunities) and migration networks (including ethnic links), migration policy has a powerful influence on the scale, directions and characteristics of human flows.

The NSA: the impact of the wiretapping scandal on German-American relations. OSW Commentary No. 124, 14.01.2014

Edward Snowden revealed that America’s National Security Agency (NSA) had tapped Chancellor Angela Merkel’s mobile phone and had collected date en masse. This has caused the largest crisis of confidence in relations between Germany and the US since the Iraq war. Due to the technological advantage which American intelligence services have, Germany wishes to continue close co-operation with the US but is making efforts to change the legal basis of this co-operation dating back to Cold War times. Berlin would like to secure part of provisions similar to the Five Eyes alliance – agreements signed between the US, the UK, Canada, New Zealand and Australia in the second half of the 1940s, aimed at intelligence sharing and a ban mutual bugging. This could spell the end of the last (not including the military presence) relic of Germany’s dependence on the US which emerged following World War II and took shape in the shadow of the Cold War. The process of Germany’s emancipation in trans-Atlantic relations, which began after Germany’s reunification, would be complete. The US is however opposed to such far-reaching changes as it is interested in continued co-operation with Germany without limiting it. Were it not to sign agreements satisfactory for Berlin, this would lead to a protracted crisis of confidence in German-American relations.

Gagauzia: growing separatism in Moldova? OSW Commentary No. 129, 10.03.2014

On 2 February, the regional authorities in Gagauzia - an autonomous region of the Republic of Moldova - carried out two simultaneous referenda. In the first, local residents were asked to declare their support for the country’s integration either with the EU or with the Moscow-led Customs Union (CU); the second referendum sought their opinion on the draft law “On the deferred status of the Autonomous Region of Gagauzia”. Under the proposed legislation, if Moldova were to lose its sovereignty (for example, through the unification of Moldova and Romania, or even as some politicians have argued, through Moldova’s further integration with the EU), the autonomous region would automatically become the independent Republic of Gagauzia. As expected, the outcome of the vote has shown overwhelming support for both the CU and for the draft law. According to the figures released by Gagauzia’s Central Electoral Commission, 98.5% of the voters supported Moldova’s integration with the Customs Union, while 98% voted in favour of the ‘deferred independence’ bill. Support for closer integration with the EU was marginal, reaching just over 2%. Despite the one-sided outcome of the referendum, there is no reliable evidence to suggest that the ballot was rigged. It should also be noted that voter turnout was very high, reaching about 70%. Representatives of the Moldovan Central Electoral Commission, however, believe that the figure may have been artificially inflated by excluding many of the voters currently residing abroad from the count.