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Purpose: After Endoscopic Enucleation of the Prostate (EEP) for benign prostatic obstruction (BPO), men remain at risk for prostate cancer (PCa). Significant PSA changes occur after enucleation, which interfere with later screening for PCa. It remains unclear which patients need further diagnostic investigations for PCa after EEP. The goal of this study was to identify an independent predictor for PCa diagnosis after Holmium Laser Enucleation of the Prostate (HoLEP) in patients whose HoLEP resection specimen did not show PCa. Methods: Data of 773 patients who underwent HoLEP for BPO between 2010 and 2018 in a referral center were analyzed. Exclusion criteria were PCa detection in the HoLEP specimen or absence of post-operative PSA values. Patients were divided in a PCa group and Control group depending on whether or not PCa was detected during follow-up after HoLEP. The predictive value for future diagnosis of PCa of different forms of PSA-change after HoLEP was analyzed by multivariate Cox regression and ROC analysis. Results: Overall, 24 (4.2%) patients developed PCa after HoLEP. At 5 year follow-up, the PCa-free survival rate was 85%. First post-operative PSA was an independent predictor of PCa diagnosis after HoLEP (HR 1.106, 95% CI 1.074–1.139, p < 0.001, ROC AUC 0.903) with an optimal cut-off value of 1.73 ng/ml (sensitivity 83.3%, specificity 82.3%). Conclusions: For patients who underwent HoLEP for BPO, post-operative PSA after HoLEP is an independent predictor for future PCa diagnosis. When PSA is > 1.73 ng/ml within the first year after HoLEP, rigorous follow-up and diagnostic investigations for PCa are indicated. [ABSTRACT FROM AUTHOR]

We present the results of combined INTEGRAL and XMM–Newton   observations of the supergiant fast X-ray transient (SFXT) IGR J17354−3255. Three XMM–Newton   observations of lengths 33.4, 32.5, and 21.9 ks were undertaken, the first an initial pointing to identify the correct source in the field of view and the latter two performed around periastron. Simultaneous INTEGRAL observations across |${\sim }66\,{\rm {per \, cent}}$| of the orbital cycle were analysed but the source was neither detected by IBIS/ISGRI nor by JEM-X. The XMM–Newton  light curves display a range of moderately bright X-ray activity but there are no particularly strong flares or outbursts in any of the three observations. We show that the spectral shape measured by XMM–Newton  can be fitted by a consistent model throughout the observation, suggesting that the observed flux variations are driven by obscuration from a wind of varying density rather than changes in accretion mode. The simultaneous INTEGRAL data rule out simple extrapolation of the simple power-law model beyond the XMM–Newton  energy range. [ABSTRACT FROM AUTHOR]

The aim of this paper is to point out that the classic seismological problem using observations and theoretical expressions for the periods and damping times of transverse standing magnetohydrodynamic waves in coronal loops is better referred to as a reduced seismological problem. "Reduced" emphasises the fact that only a small number of characteristic quantities of the equilibrium profiles can be determined. Reduced also implies that there is no unique solution to the full seismological problem. Even the reduced seismological problem does not allow a unique solution. Bayesian inference results support our mathematical arguments and offer insight into the relationship between the algebraic and the probabilistic inversions. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to evaluate the changes in maternal quality of life (QOL) from pregnancy to 6 weeks after delivery between routine labor epidural analgesia (EA) and pain relief on maternal request only.Methods: \Women delivering of a singleton in cephalic presentation beyond 36 + 0 weeks' gestation were randomly allocated to EA as a routine during labor (routine EA group), or to any kind of analgesia on request only (control group). The Short Form health survey (SF-36) was used to assess women's QOL before randomization, and 6 weeks postpartum. Data were analyzed according to the intention to treat principle.Results: A total of 488 women were included, and antepartum as well as postpartum SF-36 questionnaires were filled in by 356 (73.0%) women, 176 (49.4%) in the routine EA group, and 180 (50.6%) in the control group. Changes from the QOL antepartum to the QOL 6 weeks postpartum were comparable between both groups, also in the subgroup of women in the control group who gave birth without any pain medication (n = 41, 22.8%). Maternal age and the incidence of adverse events related to EA, which were both higher in the routine EA group, had no influence on the changes in QOL. Differences in request for pain relief were comparable with other studies.Conclusion: Routine administration of EA during labor and pain relief on maternal request only are associated with comparable changes of women's QOL antepartum to 6 weeks postpartum. [ABSTRACT FROM AUTHOR]

The ratio of the period of the fundamental mode to that of the first overtone of kink oscillations (hereafter period ratio) is a seismology tool that can be used to infer information about the spatial variation of density along solar magnetic flux tubes. The period ratio is 2 in longitudinally homogeneous thin tubes, but it differs from 2 because of longitudinal inhomogeneity. In this paper we investigate the period ratio in longitudinally inhomogeneous prominence threads and explore its implications for prominence seismology. We numerically solve the two-dimensional eigenvalue problem of kink oscillations in a model of a prominence thread. We take into account three nonuniform density profiles along the thread. In agreement with previous works that used simple piecewise constant density profiles, we find that the period ratio is larger than 2 in prominence threads. When the ratio of the central density to that at the footpoints is fixed, the period ratio depends strongly on the form of the density profile along the thread. The more concentrated the dense prominence plasma near the center of the tube, the larger the period ratio. However, the period ratio is found to be independent of the specific density profile when the spatially averaged density in the thread is the same for all the profiles. An empirical fit of the dependence of the period ratio on the average density is given and its use for prominence seismology is discussed. [ABSTRACT FROM AUTHOR]

Background Mammographic screening may reduce breast cancer mortality by about 20%, provided participation is high and women screen regularly. We quantified independent risk factors for failing to rescreen and built a model to predict how rescreening rates change if these risk factors would be modified. Methods Multivariate analysis was used to analyze data from a prospective study which included a self-administered questionnaire and rescreening status 30 months after a t0 mammogram, using a random sample of women 50-67 years (Belgium 2010-2013). Results A false positive result at the most recent past mammogram (Odds Ratio = 5.0, 95% Confidence Interval 3.6-6.8), an interval until new invitation greater than 25 months (Odds Ratio = 4.8 for > 29 months, 95% Confidence Interval 2.9-8.1), waiting times in the mammography unit > 1 h (Odds Ratio = 2.1, 95% Confidence Interval 1.2-3.7) and difficulties in reaching the unit (Odds Ratio = 2.5, 95% Confidence Interval 1.4-4.4) were the strongest independent predictors for failing to rescreen. The area under the curve of the receiver operating characteristic analysis was 0.705 for the model development stage and 0.717 for the validation stage and goodness-of-fit was good. Conclusions Maintaining an invitation cycle of maximum 25 months, limiting waiting time in the mammography unit and lowering the number of false positives could increase breast cancer screening compliance. [ABSTRACT FROM AUTHOR]

We present rare observational evidence of vertical kink oscillations in a laminar and diffused large-scale plasma curtain as observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. The X6.9-class flare in active region 11263 on 2011 August 9 induces a global large-scale disturbance that propagates in a narrow lane above the plasma curtain and creates a low density region that appears as a dimming in the observational image data. This large-scale propagating disturbance acts as a non-periodic driver that interacts asymmetrically and obliquely with the top of the plasma curtain and triggers the observed oscillations. In the deeper layers of the curtain, we find evidence of vertical kink oscillations with two periods (795 s and 530 s). On the magnetic surface of the curtain where the density is inhomogeneous due to coronal dimming, non-decaying vertical oscillations are also observed (period ≈ 763-896 s). We infer that the global large-scale disturbance triggers vertical kink oscillations in the deeper layers as well as on the surface of the large-scale plasma curtain. The properties of the excited waves strongly depend on the local plasma and magnetic field conditions. [ABSTRACT FROM AUTHOR]

Recently, a significant amount of transverse wave energy has been estimated propagating along solar atmospheric magnetic fields. However, these estimates have been made with the classic bulk Alfvén wave model which assumes a homogeneous plasma. In this paper, the kinetic, magnetic, and total energy densities and the flux of energy are computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant or continuous radial density profile. There are fundamental deviations from the properties for classic bulk Alfvén waves. (1) There is no local equipartition between kinetic and magnetic energy. (2) The flux of energy and the velocity of energy transfer have, in addition to a component parallel to the magnetic field, components in the planes normal to the magnetic field. (3) The energy densities and the flux of energy vary spatially, contrary to the case of classic bulk Alfvén waves. This last property has the important consequence that the energy flux computed with the well known expression for bulk Alfvén waves could overestimate the real flux by a factor in the range 10-50, depending on the flux tube equilibrium properties. [ABSTRACT FROM AUTHOR]

Context. Magnetic twist is thought to play an important role in coronal loops. The effects of magnetic twist on stable magnetohydrodynamic (MHD) waves is poorly understood because they are seldom studied for relevant cases. Aims. The goal of this work is to study the fingerprints of magnetic twist on stable transverse kink oscillations. Methods. We numerically calculated the eigenmodes of propagating and standing MHD waves for a model of a loop with magnetic twist. The azimuthal component of the magnetic field was assumed to be small in comparison to the longitudinal component. We did not consider resonantly damped modes or kink instabilities in our analysis. Results. For a nonconstant twist the frequencies of the MHD wave modes are split, which has important consequences for standing waves. This is different from the degenerated situation for equilibrium models with constant twist, which are characterised by an azimuthal component of the magnetic field that linearly increases with the radial coordinate. Conclusions. In the presence of twist standing kink solutions are characterised by a change in polarisation of the transverse displacement along the tube. For weak twist, and in the thin tube approximation, the frequency of standing modes is unaltered and the tube oscillates at the kink speed of the corresponding straight tube. The change in polarisation is linearly proportional to the degree of twist. This has implications with regard to observations of kink modes, since the detection of this variation in polarisation can be used as an indirect method to estimate the twist in oscillating loops. [ABSTRACT FROM AUTHOR]

The propagation of nonlinear nonaxisymmetric waves along a magnetic tube in an incompressible plasma embedded in a magnetic-free plasma is studied. The plasma and magnetic parameters in the tube core as well as plasma parameters in the external plasma are constant. Between the tube core and the magnetic-free plasma there is a thin annulus where the Alfvén speed monotonically decreases to zero. In this annulus there is a cylindrical surface where the phase speed of the global wave matches the local Alfvén speed. In the vicinity of this surface there is an efficient conversion of the global wave energy in the energy of local Alfvén waves. This results in the resonant absorption of the global wave and, as a consequence, in the global wave damping. The wave amplitude is assumed to be small and used as a small parameter in the singular perturbation method that is used to derive the nonlinear governing equation for nonaxisymmetric waves. This equation accounts both for nonlinearity and wave damping due to resonant absorption. A particular class of solutions of this equation in the form of helical waves is studied numerically. The main result obtained in this study is that nonlinearity accelerates the wave damping. It also distorts the shape of the tube boundary due to nonlinear generation of fluting modes. [ABSTRACT FROM AUTHOR]

The efficacy of fast – slow MHD mode conversion in the surface layers of sunspots has been demonstrated over recent years using a number of modelling techniques, including ray theory, perturbation theory, differential eigensystem analysis, and direct numerical simulation. These show that significant energy may be transferred between the fast and slow modes in the neighbourhood of the equipartition layer where the Alfvén and sound speeds coincide. However, most of the models so far have been two dimensional. In three dimensions the Alfvén wave may couple to the magnetoacoustic waves with important implications for energy loss from helioseismic modes and for oscillations in the atmosphere above the spot. In this paper, we carry out a numerical “scattering experiment,” placing an acoustic driver 4 Mm below the solar surface and monitoring the acoustic and Alfvénic wave energy flux high in an isothermal atmosphere placed above it. These calculations indeed show that energy conversion to upward travelling Alfvén waves can be substantial, in many cases exceeding loss to slow (acoustic) waves. Typically, at penumbral magnetic field strengths, the strongest Alfvén fluxes are produced when the field is inclined 30° – 40° from the vertical, with the vertical plane of wave propagation offset from the vertical plane containing field lines by some 60° – 80°. [ABSTRACT FROM AUTHOR]

A formulation with the flow as the prime source of instability and dissipation as a triggering mechanism is presented as an alternative to the "negative energy" formulation of instabilities of parallel flows. The formulation is based on the linear wave energy equation. The apparent opposition between the "negative energy" wave formulation and the linear wave energy formulation, where the wave energy is always positive, is resolved. [ABSTRACT FROM AUTHOR]

The linear spectrum of 1-D magnetostatic and thermally conducting equilibrium plasmas is analyzed. It is found that the influence of thermal conduction is fundamentally different on the various parts of the linear spectrum of ideal magnetohydrodynamics and that it is by far the most profound for the slow magnetoacoustic part. The ideal Alfvén continuous spectrum is unaffected by thermal conduction. However, the ideal slow continuous spectrum is replaced by the isothermal slow continuous spectrum. This new continuous spectrum owes its existence to thermal conduction but is independent of κ and involves a different range of continuum frequencies. In addition to these two continuous parts, the spectrum consists of discrete slow and fast magnetoacoustic modes and thermal modes. The point eigenvalues of the fast magnetoacoustic modes are slightly distorted in proportion to κ. However, the point eigenvalues of the slow magnetoacoustic modes lie on well-defined curves in the complex plane that are independent of κ and controlled by the ideal slow and isothermal slow continua. The discrete slow magnetoacoustic spectrum hangs, as it were, on the ideal slow and isothermal slow continua and is determined by the nonuniformity of the equilibrium. The thermal modes are the result of the inclusion of the nonideal effect of thermal conduction in the energy equation. [ABSTRACT FROM AUTHOR]

Examines the interaction of sound waves with a static one-dimensional planar magnetic plasma configuration. Use of the nonlinear theory of driven magnetohydrodynamic waves in the resonant slow wave dissipative layer developed by Ruderman, Hollweg and Goossens; Configuration description.

Focuses on multifaceted asymmetric radiation from the edge (MARFE) as a radiative thermal instability in a one-dimensional cylindrical equilibrium model. Use of magnetohydrodynamic equations for a global idea of the MARFE onset; Occurrence of perturbations of pressure and magnetic field; Relation between critical density and plasma current.

The linear magnetohydrodynamic (MHD) spectrum of an infinite straight cylinder is investigated, taking nonadiabatic terms in the energy equation into account. It is shown that in nonideal MHD, a new continuum arises. Unlike the ‘‘classical’’ Alfvén and slow continua, this thermal continuum consists of modes that are purely exponentially growing or decaying in time. Thus unstable continua can be encountered. [ABSTRACT FROM AUTHOR]

Comments on the research 'Alfven 'resonance' reconsidered: Exact equations for wave propagation across a cold inhomogeneous plasma,' by P.M. Bellan, which appeared in the journal 'Physics of Plasmas.' Bellan's statements on problems associated with Alfven's resonance in magnetohydrodynamics; Incorrect conclusion that there is no resonance in plasma.

Background: We examined 15 years of key performance indicators (KPIs) of the population-based mammography screening programme (PMSP) in Flanders, Belgium.Methods: Individual screening data were linked to the national cancer registry to obtain oncological follow-up. We benchmarked crude KPI results against KPI-targets set by the European guidelines and KPI results of other national screening programmes. Temporal trends were examined by plotting age-standardised KPIs against the year of screening and estimating the Average Annual Percentage Change (AAPC).Results: PMSP coverage increased significantly over the period of 15 years (+ 7.5% AAPC), but the increase fell to + 1.6% after invitation coverage was maximised. In 2016, PMSP coverage was at 50.0% and opportunistic coverage was at 14.1%, resulting in a total coverage by screening of 64.2%. The response to the invitations was 49.8% in 2016, without a trend. Recall rate decreased significantly (AAPC -1.5% & -5.0% in initial and subsequent regular screenings respectively) while cancer detection remained stable (AAPC 0.0%). The result was an increased positive predictive value (AAPC + 3.8%). Overall programme sensitivity was stable and was at 65.1% in 2014. In initial screens of 2015, the proportion of DCIS, tumours stage II+, and node negative invasive cancers was 18.2, 31.2, and 61.6% respectively. In subsequent regular screens of 2015, those proportions were 14.0, 24.8, and 65.4% respectively. Trends were not significant.Conclusion: Besides a suboptimal attendance rate, most KPIs in the Flemish PMSP meet EU benchmark targets. Nonetheless, there are several priorities for further investigation such as a critical evaluation of strategies to increase screening participation, organising a biennial radiological review of interval cancers, analysing the effect that preceding opportunistic screening has on the KPI for initial screenings, and efforts to estimate the impact on breast cancer mortality. [ABSTRACT FROM AUTHOR]

Generalising the Elsässer variables, we introduce the $Q$ -variables. These are more flexible than the Elsässer variables, because they also allow us to track waves with phase speeds different than the Alfvén speed. We rewrite the magnetohydrodynamics (MHD) equations with these $Q$ -variables. We consider also the linearised version of the resulting MHD equations in a uniform plasma, and recover the classical Alfvén waves, but also separate the fast and slow magnetosonic waves into upward- and downward-propagating waves. Moreover, we show that the $Q$ -variables may also track the upward- and downward-propagating surface Alfvén waves in a non-uniform plasma, displaying the power of our generalisation. In the end, we lay the mathematical framework for driving solar wind models with a multitude of wave drivers. [ABSTRACT FROM AUTHOR]

Introduction: Painful Diabetic Neuropathy (PDN) is known to negatively affect psychosocial functioning as expressed by enhanced levels of anxiety and depression. Objective: To specify diabetes and pain related fears, hereby identifying potential targets for intervention. Patients: This questionnaire-based cross-sectional study included 154 patients with PDN (mean age 65.7 ± 6.6 years). Methods: Linear regression analyses corrected for age, gender, pain intensity, pain duration and insulin treatment were performed to assess the associations of various fear questionnaires (Hypoglycaemia Fear Survey (HFS), Tampa Scale of Kinesiophobia (TSK), Pain Anxiety Symptom Scale (PASS-20), Falls Efficacy Scale-I (FES-I), Tampa Scale of Fatigue (TSF), Brief Fear of Negative Evaluation Scale (BFNE)) with quality of life (QoL) (Norfolk Quality of Life Questionnaire, Diabetic Neuropathy Version, QOL-DN) and disability (Pain Disability Index, PDI), respectively. Results: All fears were independently associated with QoL and disability (p < 0.001 for all variables). Stepwise backward regression models including all fear questionnaires showed that pain intensity, fear of fatigue, fear of hypoglycaemia and fear of falling were significantly associated with decreased QoL; β = 0.253; p < 0.001; β = 0.134; p = 0.045; β = 0.216; p = 0.003, and β = 0.385; p < 0.001, respectively; R2 = 0.629. Pain intensity and fear of falling were significantly associated with disability; β = 0.283; p < 0.001 and β = 0.540; p < 0.001 respectively; R2 = 0.544. Conclusion: In patients with PDN, pain intensity, fear of falling, fear of hypoglycemia and fear of fatigue were associated with decreased QoL. Pain intensity and fear of falling were associated with disability. Clinical message: Unravelling specific fears enables us to identify targets for behavioural interventions that aim to improve psychosocial well-being in patients with PDN. [ABSTRACT FROM AUTHOR]

Magnetohydrodynamic (MHD) kink waves have now been observed to be ubiquitous throughout the solar atmosphere. With modern instruments, they have now been detected in the chromosphere, interface region, and corona. The key purpose of this paper is to show that kink waves do not only involve purely transverse motions of solar magnetic flux tubes, but the velocity field is a spatially and temporally varying sum of both transverse and rotational motion. Taking this fact into account is particularly important for the accurate interpretation of varying Doppler velocity profiles across oscillating structures such as spicules. It has now been shown that, as well as bulk transverse motions, spicules have omnipresent rotational motions. Here we emphasize that caution should be used before interpreting the particular MHD wave mode/s responsible for these rotational motions. The rotational motions are not necessarily signatures of the classic axisymmetric torsional Alfvén wave alone, because kink motion itself can also contribute substantially to varying Doppler velocity profiles observed across these structures. In this paper, the displacement field of the kink wave is demonstrated to be a sum of its transverse and rotational components, both for a flux tube with a discontinuous density profile at its boundary, and one with a more realistic density continuum between the internal and external plasma. Furthermore, the Doppler velocity profile of the kink wave is forward modeled to demonstrate that, depending on the line of sight, it can either be quite distinct or very similar to that expected from a torsional Alfvén wave. [ABSTRACT FROM AUTHOR]

Observations show that propagating magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. The technique of MHD seismology uses the wave observations combined with MHD wave theory to indirectly infer physical parameters of the solar atmospheric plasma and magnetic field. Here, we present an analytical seismological inversion scheme for propagating MHD waves. This scheme uses the observational information on wavelengths and damping lengths in a consistent manner, along with observed values of periods or phase velocities, and is based on approximate asymptotic expressions for the theoretical values of wavelengths and damping lengths. The applicability of the inversion scheme is discussed and an example is given. [ABSTRACT FROM AUTHOR]

Aims: General analytical formulas for the damping rate by resonant absorption of slow sausage modes in the slow (cusp) continuum are derived and the resonant damping of the slow surface mode under photospheric conditions is investigated. Methods. The connection formula across the resonant layer is used to derive the damping rate for the slow sausage mode in the slow continuum by assuming a thin boundary. Results: It is shown that the effect of the resonant damping on the slow surface sausage mode in the slow continuum, which has been underestimated in previous interpretations, could be effcient under magnetic pore conditions. A simplified analytical formula for the damping rate of slow surface mode in the long wavelength limit is derived. This formula can be useful for a rough estimation of the damping rate due to resonant absorption for observational wave damping. [ABSTRACT FROM AUTHOR]

Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. Alfvén waves and magneto-sonic waves are particular classes of MHD waves. These wave modes are clearly different and have pure properties in uniform plasmas of infinite extent only. Due to plasma non-uniformity, MHD waves have mixed properties and cannot be classified as pure Alfvén or magneto-sonic waves. However, vorticity is a quantity unequivocally related to Alfvén waves as compression is for magneto-sonic waves. Here, we investigate MHD waves superimposed on a one-dimensional non-uniform straight cylinder with constant magnetic field. For a piecewise constant density profile, we find that the fundamental radial modes of the non-axisymmetric waves have the same properties as surface Alfvén waves at a true discontinuity in density. Contrary to the classic Alfvén waves in a uniform plasma of infinite extent, vorticity is zero everywhere except at the cylinder boundary. If the discontinuity in density is replaced with a continuous variation of density, vorticity is spread out over the whole interval with non-uniform density. The fundamental radial modes of the non-axisymmetric waves do not need compression to exist unlike the radial overtones. In thin magnetic cylinders, the fundamental radial modes of the non-axisymmetric waves with phase velocities between the internal and the external Alfvén velocities can be considered as surface Alfvén waves. On the contrary, the radial overtones can be related to fast-like magneto-sonic modes. [ABSTRACT FROM AUTHOR]

Magnetoacoustic waves in solar magnetic flux tubes may be affected by the presence of background rotational flows. Here, we investigate the behaviour of m  = 0 and m  = ±1 modes of a magnetic flux tube in the presence of linear background rotational flows embedded in a photospheric environment. We show that the inclusion of a background rotational flow is found to have little effect on the obtained eigensolutions for the axisymmetric m  = 0 sausage mode. However, solutions for the kink mode are dependent on the location of the flow resonance modified by the slow frequency. A background rotational flow causes the modified flow resonances to possess faster phase speeds in the thin-tube (TT) limit for the case m  = 1. This results in solutions for the slow body and slow surface kink modes to follow this trajectory, changing their dispersive behaviour. For a photospheric flux tube in the TT limit, we show that it becomes difficult to distinguish between the slow surface and fast surface kink (m  = 1) modes upon comparison of their eigenfunctions. 2D velocity field plots demonstrate how these waves, in the presence of background rotational flows, may appear in observational data. For slow body kink modes, a swirling pattern can be seen in the total pressure perturbation. Furthermore, the tube boundary undergoes a helical motion from the breaking of azimuthal symmetry, where the m  = 1 and m  = −1 modes become out of phase, suggesting the resulting kink wave is circularly polarized. These results may have implications for the seismology of magnetohydrodynamic waves in solar magnetic vortices. [ABSTRACT FROM AUTHOR]

Introduction: Phenotype studies still occupy a key position in the diagnosis of hemoglobin (Hb) disorders. Material and Methods: In addition to the conventional methods for diagnosis of Hb disorders which are mostly based on differences in charge of the Hb molecules, some progresses have been brought by studying other properties of the globin chains. Among those, difference in hydrophobicity that may be investigated by reversed-phase HPLC (RP-HPLC) discriminates between variants displaying identical charges. Results: In this study, we show how an update of this method allows to recognize an α-chain variant from a γ-chain variant, a problem frequently during neonatal screening. We illustrate that RP-HPLC may also unravel unclear phenotypes which are modified by the presence of an additional variant not detected by the conventional methods, and help to characterize rare mutants. Also we show that it allows a clear distinction between variants with identical electrophoretical charges as exemplified by Hb Lepore Boston-Washington and Lepore Baltimore. Conclusions: In view of our results, RP-HPLC is a technique that needs to be used as a second step in the general strategy for a correct characterization of Hb variants. [ABSTRACT FROM AUTHOR]

The objective of this study was to use satellite imagery combined with field-based spectral analysis to assess the impacts of mining-related activities on vegetation around the smelter town of Karabash, South Ural Mountains of Russia. Time series analysis of normalized difference vegetation index (NDVI) and fraction of absorbed photosynthetically active radiation (FAPAR) images derived from Système Pour l’Observation de la Terre (SPOT)-VEGETATION was combined with the analysis of vegetation stress indices calculated from 140in situspectral measurements. Correlation analyses have revealed that vegetation stress affects vegetation density and resilience, and that it impedes a gradual increase in photosynthetic activity in the most affected areas ranging up to 10 km from the smelter. The prolongation of the growing season of healthier vegetation at greater distances, showing higher vegetation density, lower variation, and a more positive trend over time, can possibly be related to climate change. Although land cover shows a concentric pattern around Karabash, the analysis revealed that both spectral and time series-derived indices are defined more by the distance to the Karabash smelter and vegetation stress, rather than by the land cover class. [ABSTRACT FROM PUBLISHER]

Context. Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. In magnetic waveguides resonant absorption due to plasma inhomogeneity naturally transfers wave energy from large-scale motions to small-scale motions. In the cooler parts of the solar atmosphere as, e.g., the chromosphere, effects due to partial ionization may be relevant for wave dynamics and heating. Aims. We study resonant Alfvén waves in partially ionized plasmas. Methods. We use the multifluid equations in the cold plasma approximation. We investigate propagating resonant MHD waves in partially ionized flux tubes. We use approximate analytical theory based on normal modes in the thin tube and thin boundary approximations along with numerical eigenvalue computations. Results. We find that the jumps of the wave perturbations across the resonant layer are the same as in fully ionized plasmas. The damping length due to resonant absorption is inversely proportional to the frequency, while that due to ion-neutral collisions is inversely proportional to the square of the frequency. For observed frequencies in the solar atmosphere, the amplitude of MHD kink waves is more efficiently damped by resonant absorption than by ion-neutral collisions. Conclusions. Most of the energy carried by chromospheric kink waves is converted into localized azimuthal Alfvén waves that can deposit energy in the coronal medium. The dissipation of wave energy in the chromosphere due to ion-neutral collisions is only effective for high-frequency waves. The chromosphere acts as a filter for kink waves with periods shorter than 10 s. [ABSTRACT FROM AUTHOR]

Observations show the ubiquitous presence of propagating magnetohydrodynamic (MHD) kink waves in the solar atmosphere. Waves and flows are often observed simultaneously. Due to plasma inhomogeneity in the direction perpendicular to the magnetic field, kink waves are spatially damped by resonant absorption. The presence of flow may affect the wave spatial damping. Here, we investigate the effect of longitudinal background flow on the propagation and spatial damping of resonant kink waves in transversely nonuniform magnetic flux tubes. We combine approximate analytical theory with numerical investigation. The analytical theory uses the thin tube (Ti') and thin boundary (TB) approximations to obtain expressions for the wavelength and the damping length. Numerically, we verify the previously obtained analytical expressions by means of the full solution of the resistive MHD eigenvalue problem beyond the TT and TB approximations. We find that the backward and forward propagating waves have different wavelengths and are damped on length scales that are inversely proportional to the frequency as in the static case. However, the factor of proportionality depends on the characteristics of the flow, so that the damping length differs from its static analog. For slow, sub-Alfvénic flows the backward propagating wave gets damped on a shorter length scale than in the absence of flow, while for the forward propagating wave the damping length is longer. The different properties of the waves depending on their direction of propagation with respect to the background flow may be detected by the observations and may be relevant for seismological applications. [ABSTRACT FROM AUTHOR]

Heat engines provide most of our mechanical power and are essential for transportation on the macroscopic scale. However, although significant progress has been made in the miniaturization of electrostatic engines, it has proved difficult to reduce the size of liquid- or gas-driven heat engines below 107 μm3. Here we demonstrate that a crystalline silicon structure operates as a cyclic piezoresistive heat engine when it is driven by a sufficiently high d.c. current. A 0.34 μm3 engine beam draws heat from the d.c. current using the piezoresistive effect and converts it into mechanical work by expansion and contraction at different temperatures. This mechanical power drives a silicon resonator of 1.1×103 μm3 into sustained oscillation. Even below the oscillation threshold the engine beam continues to amplify the resonator's Brownian motion. When its thermodynamic cycle is inverted, the structure is shown to reduce these thermal fluctuations, therefore operating as a refrigerator. [ABSTRACT FROM AUTHOR]

The role of leaky waves in the coronal loop oscillations observed by TRACE is not yet clearly understood. In this work, the excitation of fast waves in solar coronal loops modelled as dense plasma cylindrical tubes in a uniform straight magnetic field is investigated. We study the trapped and especially leaky modes (whose energy escapes from the tube) that result from an initial disturbance by solving the time-dependent problem numerically. We find that the stationary state of the tube motion is given by the trapped normal modes. By contrast, the transient behaviour between the initial and the stationary phase is dominated by wave leakage. The so-called trig leaky modes are clearly identified since the transient behaviour shows periods and damping times that are in agreement with the values calculated from the normal-mode analysis. Consequently, these radiating modes have physical significance. However, we have not found any evidence for the excitation of other types of modes, such as the principal leaky kink mode. [ABSTRACT FROM AUTHOR]

Abstract: Electric currents across the magnetic field can occur in the solar atmosphere because of quasi-stationary magnetic shear, plasma non-uniformity, or MHD waves. We propose a new physical mechanism that can cause the anomalous dissipation of these currents and initiate energy release in solar plasmas. In the framework of linear kinetic theory, we show that the cross-field currents are unstable with respect to low-frequency perturbations. The instability growth rate is quite high, about 2% of the ion-cyclotron frequency when the differential electron/ion velocity is 0.2 of the ion thermal speed. We identify the unstable perturbations as degenerated ion-acoustic modes coupled with backward kinetic Alfvén modes. [Copyright &y& Elsevier]

A reduced self-consistent kinetic approach is developed for the study of nonlinear plasma electrodynamics near weakly magnetized regions in a current carrying collisionless plasma. In these regions in addition to quasineutral we have quasi-current-free dynamics. Quasi-current free nonlinear plasma dynamics is realized when the diamagnetic spatial dispersion parameter originating from the diamagnetic current is small compared to the plasma and field dynamic scales. In this case, the eddy currents consisting of diamagnetic and resistive parts are mutually compensated. We illustrate this effect in a liner approach to plasma electrodynamics. A quasi MHD beam-like approach to the accelerated electrons forming resistivity and a kinetic approach to the diamagnetic plasma particles allows us to develop an analytical self-similar solution to the one dimensional magnetic annihilation problem. [Copyright &y& Elsevier]

Focuses on the nonlinear behavior of driven magnetohydrodynamic waves in the slow wave dissipative layer. Use of the method of matched asymptotic expansions; Generation of a shear flow parallel to the magnetic surfaces.

We report a study of light amplification in dilute solutions of the semiconducting polymer poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT). The operating characteristics of the F8BT solution amplifier are investigated in detail, and we show that it provides a large optical gain (>40 dB/cm) across a wide (>48 nm) spectral bandwidth in the green. The saturation characteristics of the amplifier are found to be in excellent agreement with theoretical predictions, allowing an estimate of the F8BT stimulated emission cross-section, σ. We find σ∼1.7×10-16 cm2, comparable with the reported values for established laser dyes and other high-gain conjugated polymers. [ABSTRACT FROM AUTHOR]

Highlights from the article: Magnetohydrodynamics (MHD), Sun: photosphere, Sun: oscillations, errata, addenda.

We present the results of a 30 ks XMM-Newton observation of the supergiant fast X-ray transient (SFXT) SAX J1818.6-1703 - the first in-depth soft X-ray study of this source around periastron. INTEGRAL observations shortly before and after the XMM-Newton observation show the source to be in an atypically active state. Over the course of the XMM-Newton observation, the source shows a dynamic range of ⊙100 with a luminosity greater than 1 1035 erg s-1 for the majority of the observation. After an ⊙6 ks period of low-luminosity (⊙1034 erg s-1) emission, SAX J1818.6-1703 enters a phase of fast flaring activity, with flares ⊙250 s long, separated by ⊙2 ks. The source then enters a larger flare event of higher luminosity and ⊙8 ks duration. Spectral analysis revealed evidence for a significant change in spectral shape during the observation with a photon index varying from Γ ⊙2.5 during the initial low-luminosity emission phase, to Γ ⊙1.9 through the fast flaring activity, and a significant change to Γ ⊙0.3 during the main flare. The intrinsic absorbing column density throughout the observation (nH ⊙5 1023 cm-2) is among the highest measured from an SFXT, and together with the XMM-Newton and INTEGRAL luminosities, consistent with the neutron star encountering an unusually dense wind environment around periastron. Although other mechanisms cannot be ruled out, we note that the onset of the brighter flares occurs at 3 1035erg s-1, a luminosity consistent with the threshold for the switch from a radiativedominated to Compton cooling regime in the quasi-spherical settling accretion model. [ABSTRACT FROM AUTHOR]

Aims. We aim to calculate the kinetic, magnetic, thermal, and total energy densities and the flux of energy in axisymmetric sausage modes. The resulting equations should contain as few parameters as possible to facilitate applicability for different observations. Methods. The background equilibrium is a one-dimensional cylindrical flux tube model with a piecewise constant radial density profile. This enables us to use linearised magnetohydrodynamic equations to calculate the energy densities and the flux of energy for axisymmetric sausage modes. Results. The equations used to calculate the energy densities and the flux of energy in axisymmetric sausage modes depend on the radius of the flux tube, the equilibrium sound and Alfvén speeds, the density of the plasma, the period and phase speed of the wave, and the radial or longitudinal components of the Lagrangian displacement at the flux tube boundary. Approximate relations for limiting cases of propagating slow and fast sausage modes are also obtained. We also obtained the dispersive first-order correction term to the phase speed for both the fundamental slow body mode under coronal conditions and the slow surface mode under photospheric conditions. [ABSTRACT FROM AUTHOR]