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This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Munchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers.

To predict the key parameters of the solar cycle, a new method is proposed based on the empirical law describing the correlation between the maximum height of the preceding solar cycle and the entropy of the forthcoming one. The entropy of the forthcoming cycle may be estimated using this empirical law, if the maximum height of the current cycle is known. The cycle entropy is shown to correlate well with the cy- cle's maximum height and, as a consequence, the height of the forthcoming maximum can be estimated. In turn, the correlation found between the height of the maximum and the duration of the ascending branch (the Waldmeier rule) allows the epoch of the maximum, Tmax, to be estimated, if the date of the minimum is known. Moreover, using the law discovered, one can find out the analogous cycles which are similar to the cycle being forecasted, and hence, obtain the synoptic forecast of all main features of the forthcoming cycle. The estimates have shown the accuracy level of this tech- nique to be 86%. The new regularities discovered are also interesting because they are fundamental in the theory of solar cycles and may provide new empirical data. The main parameters of the future solar cycle 24 are as follows: the height of the maximum is Wmax = 95±20, the duration of the ascending branch is Ta = 4.5±0.5 yr, the total cycle duration according to the synoptic forecast is 11.3 yr.

The properties of a magnonic crystal are expected to be strongly influenced by the presence of a thermal gradient. We investigated the propagation of backward volume and surface magnetostatic spin-waves in a 1D magnonic crystal (MC) exposed to a continuous spatial temperature gradient. It is shown that the thermal gradient applied along the propagation direction leads to a frequency shift and a modification of the transmission characteristics of the spin-waves. The frequency shift is caused by a variation in saturation magnetization due to the change in absolute temperature. The altered transmission manifests itself in a broadening of MC band gaps and the corresponding narrowing of the MC passbands and is understood to be a result of a spatial transformation of the spin-waves wavelengths in a thermal gradient. Furthermore, the transmission characteristics of spin-waves in a thermal gradient have been verified by numerical calculations based on the approach of the transmission matrix. The results of the calculations demonstrate a good agreement with the experimentally measured data.

The cycling behavior of anode materials based on alloys from the Li(Al1–zZnz) continuous solid solution has been studied. The performance of the most promising composition Li(Al0.8Zn0.2) was tested in half-cells against metallic Li with three different electrolytes and in full Li-ion cells against a V2O5cathode. The underlying structure evolution during cycling and the most relevant fatigue mechanisms are elucidated by x-ray diffraction, nuclear magnetic resonance, and x-ray photoelectron spectroscopy, and reveal a loss of mobile Li due to the ongoing formation of solid electrolyte interfaces. An enhanced stability for Li(Al1–zZnz) electrodes withz˜0.2 results from a peculiar microstructure due to the decomposition of Al and Zn in the Li-poor state and their intermixing in the Li-rich state.

To aid future observations, we present the results of N-body simulations of tidal tails near the open cluster NGC 188. The simulated tidal tails stretch in both directions along the Galactic orbit of the cluster, extending to distances of at least 1 kpc. The cross-section of a tidal tail does not exceed 40-50 pc. On the sky, the number of tidal stars in the densest parts of a tail can reach a few percent of all visible stars only. The average dispersion of stellar velocities in the tidal tail is 1-3 km s -1 . In velocity space, the tidal tails have a shape of a lengthy 'cold' star flux immersed in the 'hot' Galactic disc background. We provide the predicted position of the tidal tails and the expected distribution of radial velocities along the projection. The expected distribution of tidal star radial velocities has a large range (from -46 to +49 km s -1 ), thus underscoring the importance of predictions in future searches of tidal stars in open clusters. A preliminary search for tidal stars in the Two-Micron All-Sky Survey catalogue was not successful, indicating the need for a new CCD imaging to narrow down the number of possible former members of NGC 188 within the specified range of photometric and kinematic parameters.

Radiation-induced electron paramagnetic resonance (EPR) signals were studied in samples of plastic materials of various origin: buttons, details of underwear, elements of mobile phones, etc. The following parameters were investigated: dose response curve in the range 0-25 Gy; stability of potential dosimetric signals at different temperatures of storage after exposure; and influence of solar radiation on the dosimetric properties of materials. Plastics from personal goods were found to be a potentially acceptable material for use as individual EPR dosimeters with sensitivity threshold below 5 Gy. Radiation-induced EPR signals in plastic demonstrated clear saturation for doses above 10 Gy. Fading of dosimetric signals was best described by the two-exponential decay function with fast and slow decay components. Values of slow decay constant were approximately 2 and 15 d, while the corresponding values for the fast decay component were approximately 2 and 15 h for temperatures of +25 degrees C and -18 degrees C, respectively. Strong influence of solar light radiation on EPR spectra was observed for unexposed and gamma-irradiated plastic samples, which may affect drastically the results of dose reconstruction.

International audience; A case-control study of hematological malignancies was conducted among Chernobyl liquidators (accident recovery workers) from Belarus, Russia and Baltic countries to assess the effect of low- to medium-dose protracted radiation exposures on the relative risk of these diseases. The study was nested within cohorts of liquidators who had worked around the Chernobyl plant in 1986-1987. A total of 117 cases [69 leukemia, 34 non-Hodgkin lymphoma (NHL) and 14 other malignancies of lymphoid and hematopoietic tissue] and 481 matched controls were included in the study. Individual dose to the bone marrow and uncertainties were estimated for each subject. The main analyses were restricted to 70 cases (40 leukemia, 20 NHL and 10 other) and their 287 matched controls with reliable information on work in the Chernobyl area. Most subjects received very low doses (median 13 mGy). For all diagnoses combined, a significantly elevated OR was seen at doses of 200 mGy and above. The excess relative risk (ERR) per 100 mGy was 0.60 [90% confidence interval (CI) _0.02, 2.35]. The corresponding estimate for leukemia excluding chronic lymphoid leukemia (CLL) was 0.50 (90% CI _0.38, 5.7). It is slightly higher than but statistically compatible with those estimated from A-bomb survivors and recent low-doserate studies. Although sensitivity analyses showed generally similar results, we cannot rule out the possibility that biases and uncertainties could have led to over- or underestimation of the risk in this study.

SOHO/MDI magnetograms are used to analyze the time variations in the magnetic parameters of the active region (AR) NOAA 10486, which was part of a large activity complex that passed over the solar disk from October 26 to 31, 2003, during solar cycle 23. The results are compared with X-ray flares in the AR and the parameters of coronal mass ejections associated with the AR. The time variations in the distributions of themagnetic-field strengths associated with the total magnetic flux (Fa), the flux imbalance between the northern and southern polarities (Im), the complexity of the field, as a measure of the mutual overlapping of the opposite polarities (Co), and the tilt angle of the magnetic axis (An) are considered. The time variations in the free energy accumulated in current sheets of ARs were traced using a parameter introduced for this purpose (Sh). The following results were obtained. First, the parameters Fa, Im, Co, An, and Sh quantitatively describe the current state of the AR and can be used to trace and analyze the dynamical evolution of its magnetic field. Second, variations in the magnetic-field-strength distributions and the mean values of Fa, Im, Co, An, and Sh are associated with flares and coronal mass ejections, and the variations have considerable amplitudes. Third, the parameter Sh characterizing the degree to which the magnetic field is non-potential in regions adjacent to the main neutral line increases before eruptive events, and is thus particular interest for monitoring the states of ARs in real time. Fourth, the magnetic field of the AR manifests a sort of quasi-elasticity, so that the field structure is restored after active events, on average, within 1–3 h.

Proposed is a method for better estimation of effective dose E based on readouts of personal dosemeter calibrated in terms of personal dose equivalent Hp ( 10 ) . This method uses data on anisotropy of workplace radiation fields and parameters of distributions of conversion coefficient between Hp ( 10 ) and E . Distributions of conversion coefficients for a randomly oriented phantom were obtained by stochastic simulation for several ranges of anisotropy factor introduced for classification of workplaces. The 95 percentile of the conversion coefficient distribution applied to Hp ( 10 ) is proposed as the reasonably conservative approximation of the effective dose for moderately anisotropic photon fields.

The influence of age on tooth enamel as an EPR dosimeter has been investigated using a big collection of teeth extracted from several tens of persons living in different regions of Ukraine. The study was focused on two groups of teeth. The first one represented the urban population while the second corresponded to residents of rural settlements. Age dependences of two above groups were quite different: for example, doses for the 65–75 year age group were approximately 200 mGy higher for urban population compared to habitants of rural settlements. This effect was explained by contribution of medical X-ray exposure: the comparison of corresponding lingual and buccal doses revealed the more frequent presence of X-ray dose for urban population. Another observed effect was the difference between average intensities of native signals for two studied groups. At present time, no correlation with age was seen for this effect.

Dose profiles in teeth have been experimentally and theoretically studied for different energies and geometries of incident X- and gamma-rays. The experiments were conducted with teeth inside of an Alderson phantom using monodirectional radiation beams at selected energies; they revealed two effects: an apparent lack of dose attenuation between the buccal and the lingual sides of the teeth for energies higher than 120 keV and an attenuation between first and last tooth layers for low-energy beams in the range from 0.28 to 0.57. Monte Carlo simulations confirmed the experimental data and provided dose profiles for other energies and geometries. In particular, exposure in the rotational radiation field produces pronounced dose profiles only for energies lower than 60 keV. The usefulness of these data to estimate the average energy of accidental radiation field is discussed.

For intercomparison of methods of dose determination using electron paramagnetic resonance (EPR) spectroscopy of tooth enamel, the same sets of enamel samples were analyzed in different laboratories using similar recording parameters. The sets of samples included calibration samples irradiated in known doses, test samples irradiated to doses unknown to the participants and accidental dose samples prepared from teeth of humans affected by radioactive fallout from nuclear tests in the Semipalatinsk Nuclear Test Site in Kazakhstan. The test samples were analyzed to determine the differences in the resulting doses using different spectrometers and different spectra processing methods. The accidental dose samples were analyzed in order to test the precision of doses determined by EPR spectroscopy and to obtain more accurate values by averaging the results from different laboratories.

In order to investigate the effects of spectrum processing procedures on the results of dose determination using EPR spectroscopy of human tooth enamel, spectra of the same samples measured in different laboratories in the course of the intercomparison were processed by some of the participants using their own unique procedures. Spectra of samples irradiated to known doses (calibration samples) and of samples irradiated to doses unknown to the participants (test samples) were analyzed. By comparison of the results obtained using different spectrum processing methods, it is shown that the precision of calibration and the accuracy of dose determination may be improved by appropriate choice of spectrum processing procedure.

The determination of external dose to teeth of inhabitants of settlements near the Semipalatinsk Nuclear Test Site (SNTS) was conducted using the EPR dosimetry technique to assess radiation doses associated with exposure to radioactive fallout from the test site. In this study, tooth doses have been reconstructed for 103 persons with all studied teeth having been formed before the first nuclear test in 1949. Doses above those received from natural background radiation, termed “accident doses”, were found to lie in the range from zero to approximately 2 Gy, with one exception, a dose for one person from Semipalatinsk city was approximately 9 Gy. The variability of reconstructed doses within each of the settlements demonstrated heterogeneity of the deposited fallout as well as variations in lifestyle. The village mean external gamma doses for residents of nine settlements were in the range from a few tens of mGy to approximately 100 mGy.

The crystal structure of La 5 Ti 4 GaO 17 compound synthesized by heat-treatment of the co-precipitated hydroxy-oxalates has been determined by the X-ray powder diffraction. It was found that crystal structure of La 5 Ti 4 GaO 17 belongs to the CaLa 4 Ti 5 O 17 -type structure (space group Pmnn , a = 0.3912(1) nm, b = 3.128(1) nm, c = 0.5523(1) nm, Z = 2). The final R W value is equal to 0.081 for 169 independent reflections.

The spin wave dynamics in patterned magnetic nanostructures is under intensive study during the last two decades. On the one hand, this interest is generated by new physics that can be explored in such structures. On the other hand, with the development of nanolithography, patterned nanoelements and their arrays can be used in many practical applications (magnetic recording systems both as media and read-write heads, magnetic random access memory and spin-torque oscillators just to name a few). In the present work the evolution of spin wave spectra of an array of non-interacting Permalloy submicron circular dots for the case of magnetic field deviation from the normal to the array plane have been studied by ferromagnetic resonance technique. It is shown that such symmetry violation leads to a splitting of spin-wave modes and that the number of the split peaks depends on the mode number. A quantitative description of the observed spectra is given using a perturbation theory for small angles of field inclination from the symmetry direction. The obtained results give possibility to predict transformation of spin wave spectra depending on direction of the external magnetic field that can be important for spintronic and nanomagnetic applications.

This study aimed at investigating radiation exposure of hippocampus in interventional medical profes sionals irradiated in the operating room, and to compare doses in the hippocampus with the effective dose (protec tion quantity), as well as with the doses measured by individual dosimeter, in order to estimate probability of reach ing levels of radiation induced cognitive and other neuropsychiatric alterations during their working career, through a Monte Carlo simulation.A Monte Carlo simulation of hippocampal exposure was used by means of a hybrid voxel mathematical phantom of a doctor irradiated in typical angiographic projections and energy spectra inherent to interventional cardiology procedures.The results showed that cranial irradiation was very heterogeneous and depended on the projection: doses of left and right hippocampi may be different up to a factor of 2.5; under certain conditions, the dose of the left hippocampus may be twice the effective dose, estimated by conventional double dosimetry algorithm.The professional span doses of the irradiated hippocampus may overcome the threshold able to pro voke possible cognitive and emotional behavioral impairment. Therefore, in depth studies of the effects of brain irradiation in occupationally exposed interventional medical personnel appear urgently needed and crucial.Metoiu doslidzhennia bulo vyvchyty zakonomirnosti formuvannia doz na gipokamp v umovakh roboty likaria inter ventsiynogo kardiologa u rentgen operatsiyniy metodom Monte Karlo, a takozh vstanovyty Ikhniy zv’iazok z efek tyvnoiu dozoiu (shcho vykorystovuiet'sia u radiatsiynomu zakhysti) ta pokazanniamy indyvidual'nykh dozymetriv, shchob otsinyty ymovirnist' dosiagnennia protiagom kar’iery rivnia dozy, pry iakomu mozhut' sposterigatysia taki radiatsiyni efekty, iak kognityvni porushennia ta inshi nervovo psykhichni rozlady.Materialy i metody: modeliuvannia metodom Monte Karlo doz oprominennia gipokampiv likaria za dopomogoiu gibrydnogo voksel'no matematychnogo fantoma dlia typovykh angiografichnykh proektsiy ta energetychnykh spektriv, vlastyvykh dlia protsedur interventsiynoI kardiologiI.Rezul'taty: pokazano, shcho oprominennia golovy ie syl'no neodnoridnym i zalezhyt' vid rentgenografichnoI pro ektsiI: vidminnist' doz oprominennia livogo ta pravogo gipokampa mozhe stanovyty do dvokh z polovynoiu raziv, za pevnykh umov doza u livomu gipokampi mozhe vdvichi perevyshchuvaty efektyvnu dozu, iaku otsiniuvaly za poshyrenym algorytmom podviynoI dozymetriI.Vysnovky: dozy na gipokamp protiagom stazhu profesiynogo oprominennia mozhut' siagaty velychyn, pry iakykh mo zhut' z’iavytysia kognityvni ta emotsiyno povedinkovi porushennia, tomu glyboke vyvchennia efektiv oprominennia mozku pratsivnykiv interventsiynoI radiologiI ie vkray neobkhidnym.

DOCK7 (dedicator of cytokinesis 7) is a guanidine nucleotide exchange factor (GEF) for Rac1 GTPase that is involved in neuronal polarity and axon generation as well in Schwann cell differentiation and myelination. Recently, we identified DOCK7 as the binding partner of unconventional myosin VI (MVI) in neuronal-lineage PC12 cells and postulated that this interaction could be important in vivo [Majewski et al. (2012) Biochem Cell Biol., 90:565-574]. Herein, we found that MVI-DOCK7 interaction takes also place in other cell lines and demonstrated that MVI cargo domain via its RRL motif binds to DOCK7 C-terminal M2 and DHR2 domains. In MVI knockdown cells, lower Rac1 activity and a decrease of DOCK7 phosphorylation on Tyr1118 were observed, indicating that MVI could contribute to DOCK7 activity. MVI and DOCK7 co-localization was maintained during NGF-stimulated PC12 cell differentiation and observed also in the outgrowths. Also, during differentiation an increase in phosphorylation of DOCK7 as well as of its downstream effector JNK kinase was detected. Interestingly, overexpression of GFP-tagged MVI cargo domain (GFP-GT) impaired protrusion formation indicating that full length protein is important for this process. Moreover, a transient increase in Rac activity observed at 5min of NGF-stimulated differentiation of PC12 cells (overexpressing either GFP or GFP-MVI) was not detected in cells overexpressing the cargo domain. These data indicate that MVI-DOCK7 interaction could have functional implications in the protrusion outgrowth, and full length MVI seems to be important for delivery and maintenance of DOCK7 along the protrusions, and exerting its GEF activity.

The nearest neighbor distribution (Chandrasekhar 1943) is generalized to fractal stellar systems.For such systems an asymptotic distribution of the magnitude of large random forces and a formula for the effective mean interparticle spacing are derived. It is shown that in the case of a power-law distribution of conditional density the derived asymptotic fully agrees with the results obtained in terms of a general approach. It is concluded that large random forces in a fractal stellar medium are due entirely to the nearest neighbors (clumps) located inside the sphere of the effective radius determined from the generalized Holtsmark distribution., 10 pages, 2 figures

© 2015 Elsevier Inc. Background: Occupational and environmental exposure to chemicals such as benzene has been linked to increased risk of leukemia. Cigarette smoking and alcohol consumption have also been found to affect leukemia risk. Previous analyses in a large cohort of Chornobyl clean-up workers in Ukraine found significant radiation-related increased risk for all leukemia types. We investigated the potential for additional effects of occupational and lifestyle factors on leukemia risk in this radiation-exposed cohort. Methods: In a case-control study of chronic lymphocytic and other leukemias among Chornobyl cleanup workers, we collected data on a range of non-radiation exposures. We evaluated these and other potential risk factors in analyses adjusting for estimated bone marrow radiation dose. We calculated Odds Ratios and 95% Confidence Intervals in relation to lifestyle factors and occupational hazards. Results: After adjusting for radiation, we found no clear association of leukemia risk with smoking or alcohol but identified a two-fold elevated risk for non-CLL leukemia with occupational exposure to petroleum (OR=2.28; 95% Confidence Interval 1.13, 6.79). Risks were particularly high for myeloid leukemias. No associations with risk factors other than radiation were found for chronic lymphocytic leukemia. Conclusions: These data - the first from a working population in Ukraine - add to evidence from several previous reports of excess leukemia morbidity in groups exposed environmentally or occupationally to petroleum or its products.

In depth analysis of the results of the First National Intercomparison of individual dosimetry laboratories in Ukraine has revealed energy and angular responses of the most common types of personal dosemeters and dosi metric systems. Participating laboratories use 9 different types of dosimetric systems - automatic, semi automat ic and manual. If was found that energy dependences of the most common dosemeter types in Ukraine generally correspond to the literature data on respective TLD materials (LiF:Mg,Cu,P, LiF:Mg,TiandAl2O3:С), however, due to peculiarities of holders (filters) and dose algorithms, for some dosimetry systems the energy dependences can be improved (compensated). Angular dependences proved to be more pronounced: only two systems revealed weak dependence of response on the incident angle, for other systems at large angles (α=60°) dosemeters overestimate true dose values.Poglyblenyy analiz rezul'tativ Pershogo natsional'nogo interkalibruvannia laboratoriy IDK UkraIny dozvolyv vyvchyty energetychni ta kutovi zalezhnosti naybil'sh poshyrenykh typiv indyvidual'nykh dozymetriv ta dozymetrych nykh system. Vs'ogo laboratoriI uchasnytsi interkalibruvannia vykorystovuiut' 9 riznykh typiv dozymetrychnykh sys tem – avtomatychnykh, napivavtomatychnykh ta ruchnykh. Bulo vstanovleno, shcho energetychni zalezhnosti poshyrenykh v UkraIni typiv dozymetriv v osnovnomu vidpovidaiut' literaturnym danym dlia vidpovidnykh materialiv TLD detek toriv (LiF:Mg,Cu,P, LiF:Mg,Ti ta Al2O3:S), ale, zavdiaky osoblyvostiam korpusiv (fil'triv) dozymetriv ta dozovykh al gorytmiv, dlia okremykh system tsi energetychni zalezhnosti mozhna pokrashchyty (kompensuvaty). Kutovi zalezhnosti vidguku vyiavylys' bil'sh syl'no vyrazhenymy: til'ky dvi systemy prodemonstruvaly slabku zalezhnist' vidguku vid kuta oprominennia, dlia reshty system pry velykykh kutakh padinnia (α=60°) vidmichaiet'sia zavyshchennia pokaziv indyvidual'nykh dozymetriv.

Width-modulated dynamic magnonic crystal is developed. It utilizes a spin-wave waveguide fabricated from a single-crystal Yttrium Iron Garnet film and two conducting wires attached to the film surface between modulated and unmodulated areas. Application of electric currents to the wires produces Oersted fields that provides a means for dynamic control of the effective geometry of the waveguide and results in a suppression of the magnonic band gap. The performance of the magnonic crystal as an electric current controlled spin-wave AND logic gate is demonstrated.

The dependence of the spin-pumping effect on the yttrium iron garnet $({\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$, YIG) thickness detected by the inverse spin Hall effect (ISHE) has been investigated quantitatively. Due to the spin-pumping effect driven by the magnetization precession in the ferrimagnetic insulator ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ film a spin-polarized electron current is injected into the Pt layer. This spin current is transformed into electrical charge current by means of the ISHE. An increase of the ISHE voltage with increasing film thickness is observed and compared to the theoretically expected behavior. The effective damping parameter of the YIG/Pt samples is found to be enhanced with decreasing ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ film thickness. The investigated samples exhibit a spin mixing conductance of ${g}_{\mathrm{eff}}^{\ensuremath{\uparrow}\ensuremath{\downarrow}}=(3.87\ifmmode\pm\else\textpm\fi{}0.21)\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{0.28em}{0ex}}{\mathrm{m}}^{\ensuremath{-}2}$ and a spin Hall angle between ${\ensuremath{\theta}}_{\mathrm{ISHE}}=0.013\ifmmode\pm\else\textpm\fi{}0.001$ and $0.045\ifmmode\pm\else\textpm\fi{}0.004$ depending on the used spin-diffusion length. Furthermore, the influence of nonlinear effects on the generated voltage and on the Gilbert damping parameter at high excitation powers is revealed. It is shown that for small YIG film thicknesses a broadening of the linewidth due to nonlinear effects at high excitation powers is suppressed because of a lack of nonlinear multimagnon scattering channels. We have found that the variation of the spin-pumping efficiency for thick YIG samples exhibiting pronounced nonlinear effects is much smaller than the nonlinear enhancement of the damping.

We carried out a concerted effort to determine the absolute sign of the inverse spin Hall effect voltage generated by spin currents injected into a normal metal. We focus on yttrium iron garnet (YIG)|platinum bilayers at room temperature, generating spin currents by microwaves and temperature gradients. We find consistent results for different samples and measurement setups that agree with theory. We suggest a right-hand-rule to define a positive spin Hall angle corresponding to with the voltage expected for the simple case of scattering of free electrons from repulsive Coulomb charges., Comment: incorporated additions from the published version

The damping of spin waves parametrically excited in the magnetic insulator Yttrium Iron Garnet (YIG) is controlled by a dc current passed through an adjacent normal-metal film. The experiment is performed on a macroscopically sized YIG(100nm)/Pt(10nm) bilayer of 4x2 mm^2 lateral dimensions. The spin-wave relaxation frequency is determined via the threshold of the parametric instability measured by Brillouin light scattering (BLS) spectroscopy. The application of a dc current to the Pt film leads to the formation of a spin-polarized electron current normal to the film plane due to the spin Hall effect (SHE). This spin current exerts a spin transfer torque (STT) in the YIG film and, thus, changes the spin-wave damping. Depending on the polarity of the applied dc current with respect to the magnetization direction, the damping can be increased or decreased. The magnitude of its variation is proportional to the applied current. A variation in the relaxation frequency of +/-7.5% is achieved for an applied dc current density of 5*10^10 A/m^2.

Aims. We study the properties of magnetic field of flare-coronal-mass-ejection (flare-CME) productive active regions and their statistic correlations with CME speed. Methods. We used a sample of 86 flare-CMEs in 55 solar active regions. Four measures, including the tilt angle (Tilt ), total flux (Ft ), length of the strong-field and strong-gradient main neutral line (Lsg ) and effective distance (d E ), are used to quantify the properties of the magnetic field of flare-CME productive active regions.Results. The results are as follows: (1) for CMEs initiating in active regions, fast CMEs tend to initiate in active regions with large Ft or large d E . (2) In flare-associated CMEs, faster CMEs tend to be accompanied by more intense flares. (3) The parameters d E , Lsg and Ft correlate well with one another, especially Ft and Lsg . (4) The occurrence of 11 slow CMEs and 1 fast CME in β type regions with Lsg far below the threshold reminds us of some exceptions to be considered when Lsg with the threshold is used to predict the CME productivity of active regions.

As compared with the Mount Wilson Magnetic Classification (MWMC), effective distance (d E) is a useful parameter because it gives a quantitative measure of magnetic configuration in active regions. We have analyzed magnetograms of 24 active regions of different types with MWMC. We have studied the evolution of magnetic fields of five active regions using d E, total flux (F t) and tilt angle (Tilt) quantitatively. Furthermore, 43 flare-associated and 25 CME-associated active regions have been studied to investigate and quantify the statistical correlation between flares/CMEs and the three parameters. The main results are as follows: (1) There is a basic agreement between d E and MWMC. (2) The evolution of magnetic fields can be described in three aspects quantitatively and accurately by the three parameters, in particular by d E on the analysis of δ-type active regions. (3) The high correlation between d E and flares/CMEs means that d E could be a promising measure to predict the flare-CME activity of active regions.

Despite the considerable improvement in accuracy in comparison with previous intercomparison programmes, the outcome of the recent 3rd International Intercomparison on EPR Tooth Dosimetry has demonstrated that performance of various protocols practised in different laboratories significantly varies. SCRM and MUG took part in this intercomparison with their own versions of EPR dosimetry protocols, demonstrating the good correlation between reconstructed and nominal doses (best result for SCRM and fourth best for MUG) and the lowest both absolute and relative mean deviations from the nominal doses. Although the general results of the 3rd Intercomparison are being discussed elsewhere in this issue by Wieser et al., this presentation is focused on the discussion of the common features of the two techniques, which may have an effect on good performance in dose reconstruction. In addition to the mthods of analysis of the intercomparison results, as used in Wieser et al., SCRM and MUG studied the influence of an additional factor--the selection of the standard of the native signal--on the quality of the dose reconstruction.

The transferability of a measurement protocol from one laboratory to another is an important feature of any mature, standardised protocol. The electron paramagnetic resonance (EPR)-tooth dosimetry technique that was developed in Scientific Center for Radiation Medicine, AMS, Ukraine (SCRM) for routine dosimetry of Chernobyl liquidators has demonstrated consistent results in several inter-laboratory measurement comparisons. Transferability to the EPR dosimetry laboratory at the National Institute of Standards and Technology (NIST) was examined. Several approaches were used to test the technique, including dose reconstruction of SCRM-NIST inter-comparison samples. The study has demonstrated full transferability of the technique and the possibility to reproduce results in a different laboratory environment.

The wave front reversal (WFR) of non-reciprocal waves has been investigated. The experiment was performed using surface magnetostatic waves (SMSW) excited by a pulsed microwave signal of the carrier frequency ∼4.7 GHz in an epitaxial yttrium–iron garnet (YIG) film. The WFR was realized by pulsed parametric pumping of a double frequency. It was shown that WFR with high efficiency can be achieved for SMSW having relatively small wavenumbers k ∼10 2 rad/cm.

The calculated (models of the ideal layered perovskite-like structures (LPS)) and experimental values of the unit cell parameters of compounds of the AnBnO3n+2 type were analyzed. The interconnection between the peculiarities of the distortion of the LPS in these compounds, the number of layers of BO6 octahedra in the perovskite-like blocks, and the limits of the morphotropic transitions were established.

The newly established intermetallic compound LiAg{sub 2}In crystallizes in the MnCu{sub 2}Al-type structure (Fm-3m, Heusler phase) with a=6.5681(5)A. The homogeneity range of this phase in the ternary Li-Ag-In phase diagram along the adjacent quasibinary cut Li{sub 0.25}(Ag{sub 1-x}In{sub x}){sub 0.75} was determined by X-ray powder diffraction and extends from x{approx}0.33, Li{sub 0.25}Ag{sub 0.50}In{sub 0.25}, up to x{approx}0.44, Li{sub 0.25}Ag{sub 0.42}In{sub 0.33}. The homogeneity ranges of Heusler- and Zintl-type phases in the Li-Ag-In system are separated from each other by a broad heterogeneous region.

Stochastic self-similarity and self-affinity in the data on the solar activity phenomena is discussed in this paper. The following results are given and discussed. Firstly, the area–perimeter method was applied to obtain the fractal dimension values of solar spot umbras and of equal-intensity field lines in solar active regions (ARs). The fractal dimension value D 0=1.35±0.03 has been obtained for sunspot umbras. Field lines of equal intensity have different values of fractal dimensions for north and south polarities. Secondly, it is shown that the fractal dimension extracted from correlation between the magnetic flux and its cross-sectional area (i.e. a photosphere) is temporally invariant for an AR, but the fractal dimensions can be considerably different for various ARs. Thirdly, the multifractal nature of ARs magnetic fields was confirmed by a study of the scaling properties of their Renyi entropy. Fourthly, the R/S analysis was used for the Wolf series with purpose of estimating the long-time ‘memory...

Variability of EPR signal parameters in retrospective dosimetry with teeth has been studied among five different oblasts (regions) of Ukraine. It was found that the native signal in enamel is region-invariant and has peak-to-peak width of 0.85±0.01 mT and intensity of 1.0±0.20 normalized units. Low-frequency background signals in the spectra of enamel, 1 expressed in terms of dose were estimated to represent 15–20 mGy. Variability of radiation sensitivity among different teeth (inter-sample variability measured using 100 mg aliquots) was ±4% while among different parts of one tooth (intra-sample variability measured using 5–10 mg aliquots)—±7%.

We present here a particular application area for EPR dosimetry with teeth—use as a source of reference dose values for validation/verification of other retrospective dosimetry techniques and existing dose records. The conditions of application of EPR dosimetry in this role as well as practical design of such studies are shown. Particular attention is given to the requirements to the techniques in terms of precision and throughput, as well as to the issue of availability of samples for analysis and practical solution of this problem. Practical application of this approach is illustrated by several examples of completed validation sub-studies, which were performed in the framework of large-scale post-Chernobyl epidemiological studies.

We have determined the characteristic features of the formation of five-layer perovskites Ca5− x SrxTiNb4O17 (x=0−5) from systems of coprecipitated hydroxocarbonates. We have established that the sequence of formation for their crystal structure depends on the composition and nature of the products obtained, and is different for the individual compounds Ca5TiNb4O17, Sr5TiNb4O17, and the phases Ca5−x SrxTiNb4O17 (x=1−4).

The reversal of two-magnon relaxation associated with linear scattering of oscillations of uniform magnetization precession from sample nonuniformities is studied theoretically and experimentally in ferrite spheres of yttrium iron garnet (YIG). Relaxation reversal is performed by parametric phase conjugation of dipole-exchange spin waves formed as a result of scattering of uniform precession from inhomogeneities. As a result of two-magnon backward scattering of dipole-exchange spin waves with a certain time delay, magnetization oscillations are renewed with an amplitude that could exceed the initial amplitude of uniform precession. The relaxation reversal is due to crystallographic anisotropy of the sample and is manifested most strongly when a YIG sphere is magnetized along the intermediate axis [110]. Experiments were carried out on YIG spheres of diameter 0.65–1.05 mm for a parallel pumping frequency ωp/2π ≈ 9.4 GHz, which is about twice the uniform precession frequency. The maximal delay time for the restored signal of uniform precession was about 2 μs, while the maximal amplitude exceeded the initial uniform precession amplitude by a factor of about 5. The “latent” relaxation parameters of ferrites, e.g., the natural ferromagnetic resonance linewidth associated with many-particle processes and the linewidth associated with two-magnon scattering at bulk nonuniformities, are determined experimentally.

The matrix method of EPR spectra decomposition is developed and adapted for routine application in retrospective EPR dosimetry with teeth. According to this method, the initial EPR spectra are decomposed (using methods of matrix algebra) into several reference components (reference matrices) that are specific for each material. Proposed procedure has been tested on the example of tooth enamel. Reference spectra were a spectrum of an empty sample tube and three standard signals of enamel (two at g =2.0045, both for the native signal and one at g ⊥ =2.0018, g || =1.9973 for the dosimetric signal). Values of dosimetric signals obtained using the given method have been compared with data obtained by manual manipulation of spectra, and good coincidence was observed. This allows considering the proposed method as potent for application in routine EPR dosimetry.

In the paper the results of investigations on ten solar active regions are presented. The main results are as follows: firstly, the total down-flow velocity exceeds the up-flow velocity by about two orders of magnitude in all the active regions; secondly, no correlation was found between the mean integral velocity flux and the mean integral magnetic flux for all the active regions; thirdly, it was found that, besides a direct correlation between the total sunspot area and the total magnetic flux in active regions, occasionally there is an inverse correlation between these parameters, and the inverse correlation times often corresponded to the structural and topological rebuilding of magnetic flux in the active regions; fourthly, a good correlation was found between some parameters of integral fluxes (magnetic and velocity) and X-ray flux variations.

We present a study of the relationship between integral area and corresponding total magnetic flux for solar active regions. It is shown that some of these relationships are satisfied to simple power laws. Fractal examination showed that some of these power laws can not be justified inside the simple models of stationary magnetic flux tube aggregation. All magnetic fluxes and corresponding areas were calculated using the data measured with the Solar Magnetic Field Telescope of the Huairou Solar Observing Station in Beijing.

In this paper, several integral parameters of solar active regions are defined. The values of these parameters can be calculated from observational data. It is shown that only five of them are inde...

A method for evaluating the overall uncertainty of alanine EPR transfer dosimetry in the therapeutic dose range is described. The method uses experimental data on EPR signal reproducibility from replicate dosimeters irradiated to low doses (1–5 Gy), estimates of Type B uncertainties, and Monte Carlo simulations of heteroscedastic orthogonal linear regression. A Bruker ECS106 spectrometer and Bruker alanine dosimeters have been used for this evaluation. The results demonstrate that alanine dosimetry can be used for transfer dosimetry in that range with the overall uncertainty 1.5–4% (1σ) depending on the dose, the number of replicate dosimeters, and the duration of the calibration session (the session should not exceed one working day).

Magnons - the quanta of spin waves - propagating in magnetic materials with wavelengths at the nanometer-scale and carrying information in the form of an angular momentum, can be used as data carriers in next-generation, nano-sized low-loss information processing systems. In this respect, artificial magnetic materials with properties periodically varied in space, known as magnonic crystals, are especially promising for controlling and manipulating the magnon currents. In this article, different approaches for the realization of static, reconfigurable, and dynamic magnonic crystals are presented along with a variety of novel wave phenomena discovered in these crystals. Special attention is devoted to the utilization of magnonic crystals for processing of analog and digital information., Comment: 37 pages, 9 figures, 2 tables

An attractive direction in next-generation information processing is the development of systems employing particles or quasiparticles other than electrons—ideally with low dissipation—as information carriers. One such candidate is the magnon: the quasiparticle associated with the eigen-excitations of magnetic materials known as spin waves. The realization of single-chip all-magnon information systems demands the development of circuits in which magnon currents can be manipulated by magnons themselves. Using a magnonic crystal—an artificial magnetic material—to enhance nonlinear magnon–magnon interactions, we have succeeded in the realization of magnon-by-magnon control, and the development of a magnon transistor. We present a proof of concept three-terminal device fabricated from an electrically insulating magnetic material. We demonstrate that the density of magnons flowing from the transistor’s source to its drain can be decreased three orders of magnitude by the injection of magnons into the transistor’s gate., A disturbance in the local magnetic order can propagate across a material just like a wave. Chumak et al. now demonstrate a transistor operating on a single quantum of these so-called spin waves, known as a magnon, which could be a central element for magnetic-material-based information processing.

We present the temporal evolution of the longitudinal spin Seebeck effect in a YIG$|$Pt bilayer system. Our findings reveal that this effect is a submicrosecond fast phenomenon governed by the thermal-magnon diffusion along the thermal gradient inside the magnetic material. A comparison of experimental results with the thermal-driven magnon-diffusion model demonstrates that the temporal behavior of this effect depends on the time development of the temperature gradient in the magnetic material close to the interface. The effective thermal-magnon diffusion length for the YIG$|$Pt system is estimated to be around 500 nm.

Single phase Ba5KNb5O18 (I) is prepared by solid state reaction of Ba5Nb4O15 and KNbO3 (1370 K, 2 h), while Sr6Nb4SnO18 (II) results from calcination of the coprecipitated metal hydroxycarbonates (1570 K, 2 h).

Bose-Einstein condensation of quasi-particles such as excitons, polaritons, magnons and photons is a fascinating quantum mechanical phenomenon. Unlike the Bose-Einstein condensation of real particles (like atoms), these processes do not require low temperatures, since the high densities of low-energy quasi-particles needed for the condensate to form can be produced via external pumping. Here we demonstrate that such a pumping can create remarkably high effective temperatures in a narrow spectral region of the lowest energy states in a magnon gas, resulting in strikingly unexpected transitional dynamics of Bose-Einstein magnon condensate: the density of the condensate increases immediately after the external magnon flow is switched off and initially decreases if it is switched on again. This behaviour finds explanation in a nonlinear 'evaporative supercooling' mechanism that couples the low-energy magnons overheated by pumping with all the other thermal magnons, removing the excess heat, and allowing Bose-Einstein condensate formation.